The present invention relates to a vehicle body frame and its component members, and in particular the present invention relates to a vehicle side frame preform, a method for manufacturing a vehicle side frame and a vehicle side frame used particularly as a structural member of a vehicle frame, being a load-bearing member. The present invention relates to also a vehicle floor member preform, a vehicle floor member manufacturing method, a vehicle floor member and a vehicle floor system used particularly as a structural member of a vehicle frame being a load-bearing member and a member for mounting the vehicle suspension and the propulsion means. The present invention relates to a vehicle frame longitudinal component member preform, a method for manufacturing a vehicle frame side member, and a frame longitudinal member used particularly as a structural member of a vehicle frame being a member improving vehicle rigidity and providing vehicle controlled crumple zones. The present invention is applied in the automotive industry, and particularly in the construction of unibody structures.

The dynamic development of electric motor vehicles entails increasingly stricter requirements related to individual structural components of vehicles. Due to the relatively high weight of the power supply sources for electric motors used in vehicles, one ofthe key requirements for electric motorvehicles is to maintain low curb weight. Structures which ensure low vehicle curb weight and also the required vehicle rigidity and adequate protection of the passengers include such body types as unibody structures, sometimes also referred to as "monocoque chassis." The unibody has low curb weight, while it also presents adequately designed controlled crumple zones which disperse the forces acting on the body during collision and ensure an appropriate protection of the passenger compartment. In unibody structures, its individual component members, such as pillars, side sills, longitudinal frame members, beams, are connected to each other by welding or pressure welding. The unibody is provided with all the necessary connection elements for mounting inter alia the steering and the drive mechanisms. An important structural member of unibody frames is the side frame, which extends along the side part of the vehicle and is responsible for the rigidity of the structure and for the safety of the car body. Another important structural member of unibody frames is the floor member, which is a support element for the vehicle suspension components and which supports the necessary propulsion means, being responsible for the rigidity of the structure and for the safety of the car body. Another important structural member of unibody frames is the frame longitudinal member, i.e. the longitudinal part of the vehicle frame structure. The purpose of frame longitudinal members is to increase the rigidity of the car body and to partially absorb the energy of an impact from the front or from the back of the vehicle. Document WO2018115827A1 discloses a vehicle comprising a monocoque or a semi-monocoque body formed of a composite and forming the central body of the vehicle. Additionally, the body comprises two support members mounted externally for distributing forces around the vehicle. The first and the second support member are attached to each other for transferring forces between the two support members, wherein either the body, or the support members or all of these components are provided with a region of increased strength, and the two externally mounted support members are configured to transfer forces to this region. The patent also discloses support members which are hollow tubular components recesses formed inside. The recesses may accommodate additional reinforcements as well as foam cores. The support members may be manufactured of metal, appropriate fiber reinforced plastics, by for example molding or 3D printing.

European patent EP2895381B1 discloses a motor vehicle bodywork comprising a lateral roof frame, which is of monocoque design and which has an inner shell and an outer shell formed of sheet metal. The inner shell and the outer shell are interconnected via two flanges, enclosing a common cavity. In the cavity, there is arranged a tube, which is a reinforcement for the lateral roof frame. The reinforcing tube is made of fiber-reinforced plastic, which provides advantages in the production by allowing any shape to be formed and influencing the cost of the manufacturing process.

Document DE102005045781B4 discloses a frame structure for vehicle bodies, wagons, ships or aircraft, which has annular, self-supporting frame elements together forming the frame structure. The annular elements are connected to each other and made of multiple semi-finished products for easier transport, wherein the semi-finished products are manufactured of various materials and/or have regions of varying material thickness and/or regions of varying cross- sectional area for matching a particular desired load. Individual semi-finished products are connected with each other forming annular structural components. The connections can be made by press fitting and by other joining methods known in the art. In the disclosed document, the semi-finished products may be manufactured by bending or rolling.

European patent application EP2729348A1 discloses an understructure for a vehicle comprising elements for accommodating energy storage modules. The elements comprise at least two longitudinal members and at least two transverse members. Additionally, the cited patent document discloses a motor vehicle comprising such an understructure and an electric motor and/or an internal combustion engine. The disclosed understructure provides improved battery protection in the event of side impacts with no negative effect on the total weight or the costs. The elements for accommodating energy storage modules have at least one deformation zone having a defined deformation behavior between the energy storage modules. Known from U.S. patent US8814255B2 is a vehicle floor structure in which a main structure of the vehicle floor structure is a double deck structure including two sheets of panels formed from a fiber-reinforced thermoplastic composite material. In a region including the double deck structure, each of the panels includes two continuous reinforcing structures having a convex open cross- sectional shape, wherein recesses are provided in at least two places of the reinforcing structures. The panels are connected in such a manner that the reinforcing structures of the respective panels intersect with each other and that the recesses provided in the reinforcing structures of the respective panels are fitted to each other. The object of U.S. patent application US2017001507A1 is an underbody structure for motor vehicles configured to form a hybrid uni-body with an upper body. The underbody structure provides a configurable platform for use in multiple motor vehicle product lines, accommodating vehicles of various sizes having various upper bodies. The underbody structure comprises an outer peripheral frame which defines the battery cover and the body receiving a battery pack. The underbody structure also comprises a front bumper constructed from a cold rolled metal such as aluminum. The front bumper has a substantially tubular cross sectional area and an arcuate shape. The front bumper is coupled with a pair of rails which form the so-called crash cans. The underbody structure additionally comprises frame transition sections which are complementary components providing a narrowing connection between the left center frame section and the right center frame section. European patent application EP1671872A1 discloses a ladder-type body frame which comprises a pair of a pair of side frames extending longitudinally on both left and right sides of the body and a plurality of cross members extending crosswise between the side frames. The underbody frame of the vehicle is provided with a body reinforcement device which is attached to mounting seats located on the side frames, wherein the reinforcement device extends in a lateral direction of the body frame and comprises a means for generating hydraulic damping force which acts against deformation in the case of a collision.

Polish utility model PL69477Y1 discloses a body frame longitudinal member particularly for heavy vehicles and trailers. In its lower portion, the profile of the body frame longitudinal member comprises two U-shape chambers situated next to each other on one level, with an opening in their base, wherein the sidewalls of the U-shape chambers are connected in their profile with a flat-race base via a guiding wall inclined at an angle to the race. Parallel to both chambers, there adjoins a sidewall which protrudes below the edge of the race, and parallel to it there is a reinforcing protrusion forming an open chamber with a profiled recess on the sidewall. In the upper part of the profile, above the open chamber, there is a channel with a cylindrical cross-section, open along a part of its circumference, and it is in turn surrounded by a closed chamber, adjoined by a closed rectangular chamber and a closed triangular chamber, located respectively above the U-shape chambers in the lower part of the profile.

European patent EP3464033B1 discloses a longitudinal member for a heavy goods vehicle structure comprising a front end, intended to be oriented towards the front of the heavy goods vehicle structure, wherein the front end is provided with a hinge element for attaching the longitudinal member in an articulated manner to a heavy goods vehicle body. The longitudinal member additionally comprises a rear end, intended to be oriented towards the rear of the heavy goods vehicle, wherein the rear end comprises an attachment element for non-permanently attaching the longitudinal member to the heavy goods vehicle body. The product of the wall thickness of the front part and the yield strength of the material of the front part is greaterthan the product of the wall thickness of the rear part and the yield strength of the material of the rear part. As a result, the longitudinal member ensures energy absorption of an impact by the deformation of the rear part of the longitudinal member so that the space where the occupants of the vehicle are seated remains protected by the front part of the longitudinal member, which is substantially not deformed during the impact.

European patent EP2143621B1 discloses a car-body reinforcing member, which is manufactured by carrying out bending in which the bending direction varies two- dimensionally (in two planes) such as S-bending or bending in which the bending direction varies three-dimensionally (in three planes). The object of the cited patent is also a front frame side member which is a reinforcing member of an automobile body, and a side structure of an automobile body, and specifically a side structure of an automobile body having an A-pillar of the body, a B-pillar of the body, and a roof rail side member. The said car-body reinforcing member is a single, axially situated element which locally has a portion of high strength, which was subjected to induction hardening with high-frequency electric current and which has a tubular body with a closed cross-section. As a result, a reinforcing element was obtained having low weight, high strength, excellent impact absorbing properties, and with a reduced number of parts, and therefore with reduced manufacturing costs.

The object of European patent EP2691287 is a utility vehicle chassis and a method for manufacturing a profile longitudinal beam for such a utility vehicle chassis. The utility vehicle chassis has at least one profile longitudinal beam having a longitudinal profile extending in the longitudinal direction of the profile longitudinal beam which is coated with a corrosion prevention layer and having a web, wherein a reinforcement plate is non-detachably fastened at least to one part of the longitudinal profile. The longitudinal profile of the profile longitudinal beam is formed from a sheet-metal material by means of deformation process. The reinforcement plate is connected to the longitudinal profile exclusively by form-fitting or interference fitting, without the use of welded joints or other joints in which heat is supplied.

The technical problem of the present invention is to provide such a method for manufacturing vehicle body frame component members, including a vehicle side frame, a vehicle floor member and a vehicle frame longitudinal member, which will allow the manufacturing of the said vehicle body frame component members having desired properties, particularly with respect to the strength and the curb weight, for use as a structural member of a vehicle unibody, while maintaining a desired dimensional accuracy. It is desirable that the method for manufacturing vehicle body frame component members has a limited number of technological steps and is realized without the use of specialist and complicated apparatus, so as to directly provide economic benefits of a simplified, less time-consuming and thus cheaper manufacturing process of the vehicle body frame component members. It is also desirable that the method for manufacturing vehicle body frame component members is characterized by low material-consumption and allows the manufacturing of the vehicle body frame component members having a wide range of geometrical parameters, thus allowing the geometry and strength of the body frame component members to be adjusted to the remaining structural members of the vehicle unibody. It is also important to provide a method for manufacturing vehicle body frame component members which would allow the shape of the vehicle body frame component members to be easily modified within a wide range of geometrical parameters and without the need to rearrange the apparatus used in the manufacturing process. The technical problem of the present invention is to also provide body frame component members, including a vehicle side frame, a vehicle floor member and a vehicle frame longitudinal member, having the said properties and desired technical parameters for use in motor vehicles, particularly in vehicles provided with electric or hydrogen propulsion means.

The first object of the invention is a vehicle side frame preform, having in its side view a substantially annular structure defining an access opening to the vehicle, including a front pillar portion, a roof frame portion, a rear pillar portion and a sill portion, characterized in that the vehicle side frame preform comprises an inner wall and an outer wall made of a metal sheet, arranged with respect to each other while providing a gap forming a closed empty inner space of the vehicle side frame preform, wherein a valve element is arranged on at least one of the walls. Preferably, the vehicle side frame preform furthermore comprises at least one central pillar portion extending between the roof frame portion and the sill portion and dividing the access opening to the vehicle.

Preferably, the vehicle side frame preform has innerwall regions and/or outerwall regions having an increased thickness of the metal sheet. Preferably, the vehicle side frame preform has at least one inner pocket arranged in the gap between the inner wall and the outer wall.

Preferably, the inner pocket is in fluid communication with the valve element. Preferably, a filler is present in the inner pocket.

Preferably, the filler is a one-, two- or three-component foam or non-Newtonian fluid.

Preferably, the outer edges and/or the inner edges of the vehicle side frame preform are sealed with a seal, forming a closed hermetic empty inner space of the vehicle side frame preform.

Preferably, the seal is a fusion weld, a pressure weld, a layer of adhesive or a lap joint. Preferably, the valve element is a pneumatic or a hydraulic connection.

The second object of the invention is a method for manufacturing the vehicle side frame characterized in that the method comprises the following steps: a) a vehicle side frame preform, as defined in the first object of the invention, is provided, b) the unconnected edges of the vehicle side frame preform are sealed with a seal for forming a closed hermetic empty inner space of the vehicle side frame preform, c) a fluid under pressure is introduced through the valve element into the inner space of the vehicle side frame preform for forming a deformed vehicle side frame.

Preferably, the method for manufacturing the vehicle side frame comprises an additional step in which a fluid under pressure is introduced, through the valve element, into the inner pocket.

Preferably, step c) is performed after at least a portion of the vehicle side frame preform is introduced between pressure plates so that the pressure plates are in contact with the walls of the vehicle side frame preform for introducing at least one flattened region on a portion of the vehicle side frame preform.

Preferably, during step c) a force is applied to the pressure plates in the direction of the vehicle side frame preform. Preferably, step c) is performed by connecting a source of fluid under pressure to the valve element.

Preferably, step b) is realized by fusion welding, pressure welding, gluing or crimping.

Preferably, the fluid is air, water, oil, fluid concrete or fluid plastic. Preferably, step c) is performed in a room temperature or in an elevated temperature.

Preferably, the pressure of the fluid introduced into the vehicle side frame preform is at least 5 bars. The third object of the invention is a vehicle side frame, having in its side view a substantially annular structure defining an access opening to the vehicle, including a front pillar portion, a roof frame portion, a rear pillar portion and a sill portion, characterized in that the vehicle side frame is deformed by a fluid under pressure introduced into its hermetic empty space formed from the inner wall and the outer wall connected to each other with the corresponding seals, wherein a valve element is arranged on at least one of the walls.

Preferably, the vehicle side frame furthermore comprises at least one central pillar portion extending between the roof frame portion and the sill portion and dividing the access opening to the vehicle, wherein the central pillar portion is deformed by a fluid under pressure.

Preferably, the vehicle side frame has inner wall regions and/or outer wall regions having an increased thickness of the metal sheet.

Preferably, the vehicle side frame has at least one inner pocket arranged in the space between the inner wall and the outer wall. Preferably, the inner pocket is in fluid communication with the valve element and is deformed by a fluid under pressure introduced into the interior of the inner pocket.

Preferably, a filler is present in the inner pocket.

Preferably, the filler is a one-, two- or three-component foam or non-Newtonian fluid. Preferably, the seal is a fusion weld, a pressure weld, a layer of adhesive or a lap joint.

Preferably, the valve element is a pneumatic or a hydraulic connection.

Preferably, the fluid is air, water, oil, fluid concrete or fluid plastic. Preferably, the vehicle side frame has at least one flattened region on the inner wall and/or on the outer wall.

The fourth object of the invention is a vehicle floor member preform, having in its top view a substantially annular structure defining a storage opening, including a front frame portion, a rear frame portion, side frame portions, a front bumper portion extending from the front frame portion and a rear bumper portion extending from the rear frame portion, characterized in that the vehicle floor member preform comprises an inner wall and an outer wall made of a metal sheet, arranged with respect to each other while providing a gap forming a closed empty inner space of the vehicle floor member preform, wherein a valve element is arranged on at least one of the walls.

Preferably, the vehicle floor member preform furthermore comprises at least one frame longitudinal rib extending between the front frame portion and the rear frame portion and dividing the storage opening.

Preferably, the vehicle floor member preform furthermore comprises at least one frame transverse rib extending substantially perpendicular to the side frame portion.

Preferably, the frame longitudinal rib and/or the frame transverse rib is a member separate with respect to the substantially annular structure of the vehicle floor member. Preferably, the vehicle floor member preform furthermore comprises at least a reinforcing pillar in the region of the front bumper portion and/or in the region of the rear bumper portion.

Preferably, the reinforcing pillar is a member separate with respect to the front bumper portion and/or the rear bumper portion.

Preferably, the floor member preform has inner wall regions and/or outer wall regions having an increased thickness of the metal sheet.

Preferably, the floor member preform has inner wall regions and/or outer wall regions made of different materials.

Preferably, the vehicle floor member preform has at least one inner pocket arranged in the gap between the inner wall and the outer wall.

Preferably, the inner pocket is in fluid communication with the valve element.

Preferably, a filler is present in the inner pocket.

Preferably, the filler is a one-, two- or three-component foam or non-Newtonian fluid.

Preferably, the outer edges and/or the inner edges of the vehicle floor member preform are sealed with a seal, forming a closed hermetic empty inner space of the vehicle floor member preform.

Preferably, the seal is a fusion weld, a pressure weld, a layer of adhesive or a lap joint.

Preferably, the valve element is a pneumatic or hydraulic connection.

The fifth object of the invention is a method for manufacturing the vehicle floor member characterized in that the method comprises the following steps: a) a vehicle floor member preform, as defined in the fourth object of the invention, is provided, b) the unconnected edges of the vehicle floor member preform are sealed with a seal for forming a closed hermetic empty inner space of the vehicle floor member preform, c) a fluid under pressure is introduced through the valve element into the inner space of the vehicle floor member preform for forming a deformed vehicle floor member.

Preferably, the method for manufacturing the vehicle floor member comprises an additional step in which a fluid under pressure is introduced, through the valve element, into the inner pocket. Preferably, step c) is performed after at least a portion of the vehicle floor member preform is introduced between pressure plates so that the pressure plates are in contact with the walls of the vehicle floor member preform for introducing at least one flattened region on the portion of the vehicle floor member preform.

Preferably, during step c) a force is applied to the pressure plates in the direction of the vehicle floor member preform.

Preferably, step c) is performed by connecting a source of fluid under pressure to the valve element.

Preferably, step b) is realized by fusion welding, pressure welding, gluing or crimping. Preferably, the fluid is air, water, oil, fluid concrete, fluid plastic or flowable natural material.

Preferably, step c) is performed in a room temperature or in an elevated temperature.

Preferably the pressure of the fluid introduced into the vehicle floor member preform is at least 2 bars. The sixth object of the invention is a vehicle floor member, having in its top view a substantially annular structure defining a storage opening, including a front frame portion, a rear frame portion, side frame portions, a front bumper portion extending from the front frame portion and a rear bumper portion extending from the rearframe portion, characterized in that the vehicle floor member is deformed by a fluid under pressure introduced into its hermetic empty space formed from the inner wall and the outer wall connected to each other with the corresponding seals, wherein a valve element is arranged on at least one of the walls.

Preferably, the vehicle floor member furthermore comprises at least one frame longitudinal rib extending between the front frame portion and the rear frame portion and dividing the storage opening, wherein preferably the frame longitudinal rib is deformed by a fluid under pressure.

Preferably, the vehicle floor member furthermore comprises at least one frame transverse rib extending substantially perpendicular to the side frame portion, wherein preferably the frame transverse rib is deformed by a fluid under pressure.

Preferably, the frame longitudinal rib and/or the frame transverse rib is a member separate with respect to the substantially annular structure of the vehicle floor member and is connected thereto.

Preferably, the vehicle floor member furthermore comprises at least one reinforcing pillar in the region of the front bumper portion and/or in the region of the rear bumper portion, wherein preferably the reinforcing pillar is deformed by a fluid under pressure.

Preferably, the reinforcing pillar is a member separate with respect to the front bumper portion and/or the rear bumper portion and is connected thereto.

Preferably, the vehicle floor member has inner wall regions and/or outer wall regions having an increased thickness of the metal sheet. Preferably, the vehicle floor member has inner wall regions and/or outer wall regions made of different materials.

Preferably, the vehicle floor member has at least one inner pocket arranged in the space between the inner wall and the outer wall. Preferably, the inner pocket is in fluid communication with the valve element and is deformed by a fluid under pressure introduced into the interior of the inner pocket.

Preferably, a filler is present in the inner pocket.

Preferably, the filler is a one-, two- or three-component foam or non-Newtonian fluid.

Preferably, the seal is a fusion weld, a pressure weld, a layer of adhesive or a lap joint.

Preferably, the valve element is a pneumatic or hydraulic connection.

Preferably, the fluid is air, water, oil, fluid concrete, fluid plastic or flowable natural material.

Preferably, the vehicle floor member has at least one flattened region on the inner wall and/or on the outer wall.

The seventh object of the invention is a vehicle floor system, characterized in that the vehicle floor system comprises at least two vehicle floor members as defined in the sixth object of the invention, wherein the at least two vehicle floor members are arranged in a stack one on top of another.

Preferably, the vehicle floor system has at least one side plate which is connected with the corresponding edges of individual vehicle floor members and which ensures that the vehicle floor members are kept at a defined distance with respect to each other. Preferably, the side plate is located in the region of the side frame portion, the front bumper portion and/or the rear bumper portion.

Preferably, the side plate is a member deformed by a fluid under pressure introduced into the interior of the inner pocket.

The eighth object of the invention is a vehicle frame longitudinal member preform having in its side view a longitudinal structure comprising a front portion for being oriented towards the front of the vehicle frame and a central portion for being arranged in the central portion of the vehicle frame, characterized in that the vehicle frame longitudinal member preform comprises an inner wall and an outer wall made of a metal sheet, arranged with respect to each other while providing a gap forming a closed empty inner space of the vehicle frame longitudinal member preform, wherein a valve element is arranged on at least one of the walls.

Preferably, the vehicle frame longitudinal member preform furthermore comprises a rear portion for being oriented towards the rear of the vehicle frame.

Preferably, the central portion is offset towards the bottom of the vehicle frame with respect to the front portion.

Preferably, the front portion and/or the rear portion comprises an end annular structure.

Preferably, the transition region between the front portion and the central portion comprises a transition annular structure.

Preferably, the central portion comprises a central annular structure.

Preferably, the central portion comprises at least one reinforcing rib extending through an opening defined by the central annular structure.

Preferably, the vehicle frame longitudinal member preform has inner wall regions and/or outer wall regions having an increased thickness of the metal sheet. Preferably, the vehicle frame longitudinal member preform has inner wall regions and/or outer wall regions made of different materials.

Preferably, the outer and/or the inner edges of the vehicle frame longitudinal member preform are sealed with a seal, forming a closed hermetic empty inner space of the vehicle frame longitudinal member preform.

Preferably, the seal is a fusion weld, a pressure weld, a layer of adhesive or a lap joint.

The ninth object of the invention is a method for manufacturing the vehicle frame longitudinal member characterized in that the method comprises the following steps: a) a vehicle frame longitudinal member preform, as defined in the eighth object of the invention, is provided, b) the unconnected edges of the vehicle frame longitudinal member preform are sealed with a seal for forming a closed hermetic empty inner space of the vehicle frame longitudinal member preform, c) a fluid under pressure is introduced through the valve element into the inner space of the vehicle frame longitudinal member preform for forming a deformed vehicle frame longitudinal member.

Preferably, step c) is performed after at least a portion of the vehicle frame longitudinal member preform is introduced between pressure plates so that the pressure plates are in contact with the walls of the vehicle frame longitudinal member preform for introducing at least one flattened region on the portion of the vehicle frame longitudinal member preform.

Preferably, during step c) a force is applied to the pressure plates in the direction of the vehicle frame longitudinal member preform. Preferably, step b) is realized by fusion welding, pressure welding, gluing or crimping.

Preferably, the fluid is air, water, oil, fluid concrete, fluid plastic or flowable natural material.

The tenth object of the invention is a vehicle frame longitudinal member having in its side view a longitudinal structure comprising a front portion for being oriented towards the front of the vehicle frame and a central portion for being arranged in the central portion of the vehicle frame, characterized in that the vehicle frame longitudinal member is deformed by a fluid under pressure introduced into its hermetic empty space formed from the inner wall and the outer wall connected to each other with the corresponding seals, wherein a valve element is arranged on at least one of the walls.

Preferably, the vehicle frame longitudinal member furthermore comprises a rear portion for being oriented towards the rear of the vehicle frame.

Preferably, the central portion is offset towards the bottom of the vehicle frame with respect to the front portion.

Preferably, the front portion and/or the rear portion comprises an end annular structure.

Preferably, the transition region between the front portion and the central portion comprises a transition annular structure.

Preferably, the central portion comprises a central annular structure.

Preferably, the central portion comprises at least one reinforcing rib extending through an opening defined by the central annular structure.

Preferably, the vehicle frame longitudinal member has inner wall regions and/or outer wall regions having an increased thickness of the metal sheet. Preferably, the vehicle frame longitudinal member has inner wall regions and/or outer wall regions made of different materials.

Preferably, the seal is a fusion weld, a pressure weld, a layer of adhesive or a lap joint. Preferably, the fluid is air, water, oil, fluid concrete, fluid plastic or flowable natural material.

Preferably, the vehicle frame longitudinal member has at least one flattened region on the inner wall and/or on the outer wall.

The eleventh object of the invention is a vehicle body frame comprising the component members connected with each other, characterized in that the component members are at least one side frame as defined in the third object of the invention, at least one floor member as defined in the sixth object of the invention and at least one frame longitudinal member as defined in the tenth object of the invention. It should be stressed that the technical characteristics listed in the preferred embodiments of the invention can be freely combined with each other unless specifically indicated otherwise. The embodiments presented below are only illustrative of the objects of this invention and are not a limitation to the scope of the invention, which was defined in the appended patent claims. The method for manufacturing the vehicle body frame component members according to the present invention allows the manufacturing of vehicle body frame component members, including the vehicle side frame, the vehicle floor member and the vehicle frame longitudinal member, having desired properties, particularly with respect to forming controlled crumble zones, to the rigidity and strength of a particular vehicle body frame component member and to low curb weight. In particular, owing to the extensive use of a relatively thin metal sheet in the manufacturing of the vehicle body frame component members, the vehicle body frame component members manufactured with the method according to the invention allow a significantly decreased curb weight in comparison to classic solutions known in the art. Furthermore, the method for manufacturing the vehicle body frame component members according to the invention is realized with the use of uncomplicated machinery park, which translates into economic benefits and a significantly simplified manufacturing process of the vehicle body frame component members. A small number of seals improves the speed and lowers the labor-intensity of the vehicle body frame component members manufacturing process. Moreover, the manufacturing of the vehicle body frame component members, being structural members of the vehicle unibody, based on introducing fluid under pressure into the hermetically closed, inner space of the vehicle body frame component members preform allows the parameters of the manufactured vehicle body frame component members, and thus of the final vehicle unibody, to be modified within a wide range, in particular with respect to its final geometry, to the strength of individual zones of the vehicle body frame component members, to forming controlled crumble zones and to the rigidity of the structure.

The solution according to the present invention has been shown in the embodiments below and illustrated in the drawing, in which: Fig. 1 is an axonometric view of a vehicle unibody frame in which two vehicle side frames were used, according to one of the embodiments of the invention;

Fig. 2 is a side view of a vehicle side frame preform according to one embodiment of the invention;

Fig. 3 is a side view of a side frame according to a further embodiment of the invention; Fig. 4 is a cross-sectional view of a vehicle side frame preform during one of the steps of the method for manufacturing the vehicle side frame according to one embodiment of the invention;

Fig. 5 is a cross-sectional view of a vehicle side frame preform during one of the steps of the method for manufacturing the vehicle side frame according to a further embodiment of the invention;

Fig. 6 is a cross-sectional view of a vehicle side frame according to an embodiment of the invention;

Fig. 7 is a cross-sectional view of a vehicle side frame according to an embodiment of the invention;

Fig. 8 is a side view of a vehicle side frame according to a further embodiment of the invention, without the outer wall and showing the inner structures of the vehicle side frame;

Fig. 9 is a cross-sectional view of the vehicle side frame of fig. 8; Fig. 10 is a side view of a side frame according to a further embodiment of the invention, without the outer wall and showing the inner structures of the vehicle side frame;

Fig. 11 is a cross-sectional view of the vehicle side frame of fig. 10;

Fig. 12 is a side view of a side frame according to a further embodiment of the invention, without the outer wall and showing the inner structures of the vehicle side frame;

Fig. 13 is a cross-sectional view of the vehicle side frame of fig. 12;

Fig. 14 is a side view of a vehicle side frame manufactured in the state-of-the-art technology with indicated evaluation conditions for the strength parameter in the form of: A) compression in the vertical axis Z, B) compression in the horizontal axis X;

Fig. 15 is a side view of a vehicle side frame according to one embodiment of the invention with indicated evaluation conditions for the strength parameter in the form of: A) compression in the vertical axis Z, B) compression in the horizontal axis X;

Fig. 16 is a side view of a vehicle side frame known in the art with indicated evaluation conditions for the strength parameter in the form of: A) compression in the vertical axis Z, B) compression in the horizontal axis X; Fig. 17 is an axonometric view of a vehicle unibody frame in which a vehicle floor member was used, according to one of the embodiments of the invention;

Fig. 18 is an axonometric view of a vehicle floor member according to one embodiment of the invention;

Fig. 19 - 28 are top views of vehicle floor member preforms according to further embodiments of the invention;

Fig. 29 - 31 are axonometric views of vehicle floor systems according to further embodiments of the invention;

Fig. 32A-B is a cross-sectional view of a vehicle floor member according to an embodiment of the invention; Fig. 33 is a cross-sectional view of a vehicle floor member according to an embodiment of the invention;

Fig. 34 is a cross-sectional view of the vehicle floor member of fig. 27;

Fig. 35 is a cross-sectional view of the vehicle floor member of fig. 26;

Fig. 36 and 37 are displacement maps made for a floor member according to the invention; Fig. 38 and 39 are displacement maps made for a floor member manufactured in the state-of-the-art technology;

Fig. 40 is an axonometric view of a vehicle unibody frame with a vehicle frame longitudinal member according to one embodiment of the invention; Fig. 41 is a side view of a vehicle frame longitudinal member preform according to an embodiment of the invention;

Fig. 42 is a side view of a vehicle frame longitudinal member according to a further embodiment of the invention;

Fig. 43 is an axonometric view of frame longitudinal members according to an embodiment of the invention, mounted in the vehicle unibody frame;

Fig. 44 is a cross-sectional view of a vehicle frame longitudinal member according to an embodiment of the invention;

Fig. 45 is a side view of a vehicle frame longitudinal member preform according to a further embodiment of the invention; Fig. 46 is a side view of a vehicle frame longitudinal member according to a further embodiment of the invention;

Fig. 47 is an axonometric view of vehicle frame longitudinal members according to a further embodiment of the invention, mounted in the vehicle unibody frame;

Fig. 48 is a cross-sectional view of a vehicle frame longitudinal member according to a further embodiment of the invention;

Fig. 49 is a side view of a vehicle frame longitudinal member preform according to a further embodiment of the invention;

Fig. 50 is a side view of a vehicle frame longitudinal member according to a further embodiment of the invention; Fig. 51 is an axonometric view of vehicle frame longitudinal members according to a further embodiment of the invention, mounted in the vehicle unibody frame;

Fig. 52 is a cross-sectional view of a vehicle frame longitudinal member according to a further embodiment of the invention; Fig. 53 is a side view of a vehicle frame longitudinal member preform according to a further embodiment of the invention;

Fig. 54 and 55 are side views of a vehicle frame longitudinal member according to a further embodiment of the invention;

Fig. 56 is an axonometric view of vehicle frame longitudinal members according to a further embodiment of the invention, mounted in the vehicle unibody frame;

Fig. 57 is a cross-sectional view of a vehicle frame longitudinal member according to a further embodiment of the invention;

Fig. 58 is an axonometric view of a comparative frame model based on vehicle frame longitudinal members known in the art; Fig. 59 is an axonometric view of a frame model based on vehicle frame longitudinal members according to one embodiment of the invention;

Fig. 60 is an axonometric view of numerical simulation results presenting a stress distribution map for the structure at torsion testing;

Fig. 61 is an axonometric view of a vehicle body frame according to an embodiment of the invention.

Example 1

Fig. 1 shows an axonometric view of a vehicle unibody frame in which two vehicle side frames were used, according to the first embodiment of the invention. The first embodiment of the invention being a vehicle side frame preform is shown in a side view in Fig. 2. As depicted in Fig. 2, the vehicle side frame preform is a structure resembling an annular structure with an irregular shape. The vehicle side frame preform comprises an access opening to the vehicle, as best illustrated in the axonometric view of the vehicle unibody in Fig. 1. The vehicle side frame preform shown in Fig. 2 comprises a front pillar portion 1, a roof frame portion 2, a rear pillar portion 3 and a sill portion 4. The above listed components of the vehicle side frame preform are connected with each other and form an integral portion made of a metal sheet such as steel sheet, defining an inner wall 6 and an outer wall 7. In this embodiment, the metal sheet does not have a uniform thickness across the entire surface area of the vehicle side frame preform, but rather it has regions of various thicknesses, connected with each other and forming a "patchwork" type structure.

As shown in Fig. 2, the side frame preform is made of three regions having various thicknesses of the material sheet (in this embodiment it is a stainless steel sheet), schematically indicated with respective section lines. In this embodiment, the region having a first thickness being 1.2 mm is indicated with horizontal lines and includes the lower fragment of the front pillar portion 1, the region having a second thickness being 1.0 mm is indicated with diagonal lines and includes the sill portion 4 and the lower fragment of the rear pillar portion 3, while the region having a third thickness being 0.8 mm is indicated with vertical lines and includes the upper fragment of the front pillar portion 1, the roof frame portion 2 and the upper fragment of the rear pillar portion 3.

As a result, the inner wall 6 and the outer wall 7 are metal sheets which have varying thicknesses in individual parts of the vehicle side frame (as well as of the corresponding vehicle side frame preform). Owing to the use of the patchwork- type structure, the final vehicle side frame was given desired functional characteristics manifested in the increased strength and rigidity in the regions having increased sheet thickness. Importantly, the structure of the inner wall 6 and of the outer wall 7 is an integrated structure including regions of smaller and greater thickness of the metal sheet. The inner wall 6 and or the outer wall 7 having regions of various thickness may be obtained with any method known in the art, comprising in a non-limiting manner selective press forming, rolling and joining of sheets having different thickness, for example by welding.

However, it should be emphasized that the sheet thickness, as well as its variability in different regions of the vehicle side frame preform according to the invention is not a limitation to the scope of the invention, and in alternative embodiments of the invention it is possible to use a metal sheet having a different thickness and made of a different material, as well as "patchwork" type structures having various geometries and thicknesses, as well as numbers of regions of varying thickness. The notions of the inner wall 6 and the outer wall 7 are conventional and are intended to denote, respectively, the inner side and the outer side of the vehicle in which the vehicle side frame of the invention is used. The inner wall 6 and the outer wall 7 are arranged in alignment (on a plane) with respect to each other while providing a gap forming a closed empty inner space of the vehicle side frame preform. On one of the walls 6, 7, there is a valve element 8 arranged, which allow fluid communication with the inner space formed between the walls 6, 7 of the vehicle side frame preform.

The valve element 8 is a pneumatic or hydraulic connection and allows a leakproof fastening of a supply duct from an external source of pressurized fluid. In some embodiments of the invention, the valve element 8 may be a valve, particularly a non-return valve. The location of the valve element 8 is not a limitation to the scope of the present invention, and thus the valve element 8 may be arranged in any location on the metal sheet, on condition that a connection with the inner space of the vehicle side frame preform is allowed. In this embodiment, the outer edges and the inner edges (from the side of the access opening) of the side frame preform are sealed with a seal 12, forming a closed hermetic empty inner space of the vehicle side frame preform.

The sealing is performed on the edges of the metal sheet forming the walls 6, 7 of the vehicle side frame preform after they have been matched with each other. In this embodiment, the sealing is thus performed on all the circumferential edges of the matched walls 6, 7 of the vehicle side frame preform. In this embodiment, the sealing was performed by means of welding the corresponding edges together, forming inter alia circumferential welds. By sealing all of the above-listed edges, a leakproof hermetic inner space is formed in the vehicle side frame preform. The type of seal 12 is in this case not a limitation to the scope of the invention, and it is possible in alternative embodiments to use any type of seal 12, on condition that a leakproof inner space is formed in the vehicle side frame preform, by means for example of pressure welding, soldering, gluing, bending or pressing.

The method for manufacturing the vehicle side frame according to one of the embodiments of the invention comprises a step in which a vehicle side frame preform, as defined in this embodiment, is provided. In the case when the provided vehicle side frame preform does not have all of its circumferential edges connected and sealed, the next step comprises the sealing of the unconnected edges of the vehicle side frame preform with the seal 12 for forming a closed hermetic empty inner space of the vehicle side frame preform. As mentioned above, the seal 12 may be realized in any known fashion which ensures that a leakproof inner space is formed.

In the next step, an external source of fluid under pressure is connected to the valve element 8 through the supply duct. In this embodiment, the fluid is air, the source of fluid under pressure is a compressor, and the supply duct together with the valve element 8 form a pneumatic connection. The type of the external source of fluid under pressure and of the connection equipment is not a limitation to the scope of this invention and in alternative embodiments it is possible to use fluid in the form of water, fluid cement, machine oil, fluid plastic such as a one-, two- or three-component foam (e.g. a flex 140 type), etc. together with the connection equipment and the source of fluid under pressure appropriate forthose fluids. The less compressible the fluid is, the more controlled the deformation conditions of the vehicle side frame preform are.

In the next step of the method for manufacturing the vehicle side frame according to the invention, fluid under a defined pressure is delivered to the sealed inner space of the vehicle side frame preform. The technology of introducing fluid under pressure into closed sealed chamber elements made of sheet metal for their deformation and providing them with the final form is known inter alia from patent application No. EP2110189A1. As a result of delivering fluid under pressure into the inner space of the vehicle side frame preform, the walls 6, 7 of the vehicle side frame preform are deformed, as best illustrated in Fig. 7, which shows the cross-section of the vehicle side frame manufactured from the vehicle side frame preform. As can be observed, the walls 6, 7 of the vehicle side frame preform are significantly deformed. Importantly, the vehicle side frame according to the present embodiment of the invention has various geometrical dimensions in the front pillar portion 1, in the roof frame portion 2, in the rear pillar portion 3 and in the sill portion 4. The selection of these geometrical dimensions is dictated by the requirements used with respect both to the safety parameters, i.e. the rigidity and the strength of the structure, and forming of controlled crumble zones, and to the geometrical dimensions for the body structure. These geometrical dimensions may be freely changed as necessary and adjusted to particular applications. Note should be taken that although the introduction of fluid under pressure into the inner space of the vehicle side frame preform is performed in cold technology (i.e. in room temperature), it is not a limitation to the scope of this invention, and in alternative embodiments the process may be performed in elevated or high temperatures.

In one embodiment of the invention, the step of introducing fluid under pressure was performed with the following process parameters: - process temperature: 20 °C,

-working pressure: 5 bars,

- deformation time: 1 minute until pressure is equalized in the vehicle side frame preform,

- pressure hold time: 30 seconds, - total deformation time: 1.5 minute.

Example 2

Another embodiment of this invention is illustrated in a side view in Fig. 3, which shows the vehicle side frame.

In general, the vehicle side frame preform, as well as the vehicle side frame manufactured therefrom, is a structure substantially similarto the structure of the vehicle side frame preform and to the structure of the vehicle side frame shown in Example 1, and therefore similar structural elements will not be repeated for the clarity of this disclosure.

Importantly, the vehicle side frame shown in Fig. 3 (as well as the corresponding vehicle side frame preform) has flattened regions 9 on the inner wall 6 and on the outer wall 7, wherein the flattened regions 9 have a substantially flat outer surface. The flattened regions 9 allow an additional adjustment of the technical parameters of individual vehicle side frame portions and also are mounting regions for additional final equipment of the vehicle. The flattened regions 9 can be obtained by using the method for manufacturing the vehicle side frame according to another embodiment of the invention. Unlike in the method for manufacturing the vehicle side frame shown in Example 1, in this embodiment of the method for manufacturing the side frame, the step of introducing fluid under pressure into the inner space of the vehicle side frame preform is preceded by placing the vehicle side frame preform between the pressure plates 13 so that the pressure plates 13 are in contact with the walls 6, 7 of the vehicle side frame preform, as illustrated in Fig. 4. The pressure plates 13 may be the working elements of a mechanical press. In this case, a controlled force may be applied to the pressure plates 13, particularly in the direction towards the vehicle side frame preform. In the step of delivering fluid under pressure into the sealed inner space of the vehicle side frame preform, the vehicle side frame preform is kept between the pressure plates 13. As a result, the vehicle side frame parts manufactured with this method have flattened regions 9 in the desired vehicle side frame regions (where the linings of the pressure plates 13 were applied). The cross section of Fig. 6 shows the vehicle side frame with a region deformed in a free manner (without the use of the pressure plates 13 - on the left side) and with a region deformed with the use of the pressure plates 13 (on the right side), having flattened regions 9. Such a manufacturing method is realized in a system shown in Fig. 5, where one (left) vehicle side frame portion is not in contact with the linings of the pressure plates 13 and may be deformed in a free manner, while the second (right) vehicle side frame portion comprises walls being in contact with the pressure plates 13. It is thus possible to provide desired locations with mounting areas for vehicle functional equipment and to locally modify the technical characteristics of the vehicle side frame, such as the rigidity, the strength of the structure, or to form controlled crumble zones. In turn Fig. 7 shows a cross section of the vehicle side frame with regions deformed in a free manner (without the use of the pressure plates 13), the shown regions having different geometry, including different wall 6, 7 thickness and, after the deformation, also different vehicle side frame region thickness.

Example 3

Another embodiment of this invention is illustrated in Fig. 8, which shows a side view of the vehicle side frame without the outer wall 7 and showing the inner structures of the vehicle side frame.

In general, the vehicle side frame and the corresponding vehicle side frame preform is a structure substantially similar to the structure of the side frame and to the structure of the vehicle side frame preform shown in Example 1, the difference being that the vehicle side frame of this embodiment additionally comprises a central pillar portion 5 extending between the roof frame portion 2 and the sill portion 4 and dividing the access opening to the vehicle. The inner wall 6 and the outer wall 7 are a single integrated sheet of metal material also including a region in which the central pillar portion 5 is present. In the side view, the vehicle side frame according to the present embodiment is also an annular structure having a different spatial shape dictated by the planned application.

As depicted in Fig. 8, unlike in the vehicle side frame preform and in the corresponding vehicle side frame of Example 1, the vehicle side frame according to this embodiment comprises additional inner structures in the form of inner pockets 10. The inner pockets 10 are arranged in the gap between the inner wall 6 and the outer wall 7, as best illustrated in the cross section of Fig. 9. The inner pocket 10 is a leakproof hermetic structure with fluid communication through the valve element 8 which passes through the inner wall 6 or through the outer wall 7 of the vehicle side frame while the inner space of the vehicle side frame itself is kept sealed. The inner pocket 10 may be formed analogically to the side frame preform, i.e. from metal sheets connected with each other and sealed on the edges. In alternative embodiments, the inner pocket 10 may be formed from other materials which provide hermetic tightness to the container formed inside and which include, in a non-limiting manner, textile materials.

The embodiment of the vehicle side frame illustrated in Fig. 8 shows one inner pocket 10 comprising four regions, wherein the first region of the inner pocket 10 is in the lowerfragment of the front pillar portion 1, the second region of the inner pocket 10 is in the region of the sill portion 4, the third region of the inner pocket 10 is in the lower fragment of the central pillar portion 5, and the fourth region of the inner pocket 10 is in the lower fragment of the rear pillar portion 3.

The inner pocket 10 used in the vehicle side frame produces different results, depending on its purpose. In this embodiment, the inner pocket 10 is made from a sheet of carbon steel, wherein the entire structure of the vehicle side frame is made from a sheet of stainless steel. Carbon steel has greater hardness and strength than stainless steel, and therefore the inner pocket 10 made therefrom is an element which increases the strength of the vehicle side frame, providing it with desired technical properties. Additionally, the inner pocket 10 is deformed by fluid (air) introduced into its hermetic inner space after the vehicle side frame has been formed (by deforming the preform), allowing additional local deformations to be made in the already formed vehicle side frame and allowing the geometry of the vehicle side frame to be adjusted to a desired shape.

In another embodiment, illustrated in Fig. 10 and in Fig. 11, the inner pocket 10 is without a portion comprising the lowerfragment of the central pillar portion 5 and is made from a textile material (for example kevlar), forming a compartment in which a filler 11 is present. In this embodiment, the filler 11 is non-Newtonian fluid which allows the formation of adequately adjusted shock-absorbing zones. The inner pocket 10 with the non-Newtonian fluid may be a separate structure introduced into the vehicle side frame preform, or the inner pocket 10 may be filled with the non-Newtonian fluid after the vehicle side frame has been formed. In the latter case, the inner pocket 10 requires a valve element 8 which will serve to introduce the filler 11.

Importantly, the type of the filler 11 present in the inner pocket 10 is not limited to the non-Newtonian fluid, and in alternative embodiments the fillers 11 may be such that ensure desired technical properties (for example soundproofing level), and may include a one-, two- or three-component foam.

Example 4

Another embodiment of this invention is illustrated in Fig. 12, which shows a side view of the vehicle side frame, and in Fig. 13, which shows a cross section of the vehicle side frame of Fig. 12.

In general, the vehicle side frame and the corresponding vehicle side frame preform is a structure substantially similar to the structure of the side frame and to the structure of the vehicle side frame preform shown in Example 1, the difference being that the vehicle side frame of this embodiment additionally comprises two central pillar portions 5 extending between the roof frame portion 2 and the sill portion 4 and dividing the access opening to the vehicle. The inner wall 6 and the outer wall 7 are a single integrated sheet of metal material also including a region in which the central pillar portions 5 are present. In the side view, the vehicle side frame according to the present embodiment is also an annular structure having a different spatial shape dictated by the planned application.

In the embodiment shown in Figs. 12 and 13, the vehicle side frame comprises two inner pockets 10 being in fluid communication with the valve element 8. The front inner pocket 10 is located in the lower fragment of the front pillar portion 1 and in the front fragment of the sill portion 4, while the rear inner pocket 10 is located in the rear fragment of the sill portion 4 and extends through the region of the rear central pillar portion 5 and through the rear pillar portion 3. In this embodiment, both inner pockets 10 comprise a filler in the form of an acoustic foam, providing the vehicle side frame with desired soundproofing properties and increasing the strength parameters.

Example 5 The vehicle side frame manufactured using the method according to the invention was subjected to comparative tests (based on numerical calculations) with a vehicle side frame manufactured using traditional technology. Fig. 14 is a side view of a vehicle side frame manufactured in the state-of-the-art technology with indicated evaluation conditions for the strength parameter in the form of: A) compression in the vertical axis Z, B) compression in the horizontal axis X. The geometry of the traditional side frame corresponded to the geometry of the side frame of this invention, shown for reference in Fig. 15 A-B.

The evaluation was performed for the strength parameter in the form of compression in the vertical axis Z and in the horizontal axis X, expressed in N/mm. In the case of the traditional frame, the tests were performed for two implementations based on tubular profiles (which the individual component members of the side frame are made of) with a diameter of 32 mm and with the material thickness of 1.5 mm, and on a rectangular profile with the dimensions of 45 mm x 20 mm and with the material thickness of 1.2 mm. The results of the evaluations were compared against the corresponding strength parameters for the side frame of this invention, manufactured from sheets 0.8 mm in thickness. The calculated strength parameters are presented in Table 1. Table 1 - Comparison of side frame strength parameters

As seen from Table 1, the side frame according to the present invention is lighter than the side frames manufactured in the traditional technology with consideration to the tubular profile and the rectangular profile. The side frame of this invention (made from a 0.8 mm thick sheet) also demonstrated higher compressive rigidity parameters in both the vertical axis Z and the horizontal axis X.

Analogical comparative tests (based on numerical calculations) were performed for the vehicle side frame manufactured with the method of the invention in relation to a vehicle side frame known in the art, i.e. with the Renault Twizy (model 45 of 2015). In this case, the side frame of this invention was made from a 1.2 mm thick sheet, and the state-of-the-art side frame reflected the geometry and construction of a side frame known from the Renault Twizy (Fig. 16). The calculated strength parameters are presented in Table 2. Table 2 - Comparison of side frame strength parameters

As seen from Table 2, the side frame according to the present invention is lighter than the side frame corresponding to the frame of the vehicle known in the art. The side frame of this invention (made from a 1.2 mm thick sheet) also demonstrated higher compressive rigidity parameters in both the vertical axis Z and the horizontal axis X.

Example 6

Fig. 17 shows an axonometric view of a vehicle unibody frame in which a vehicle floor member was used, according to one embodiment of the invention. The embodiment of the invention being the vehicle floor member preform is shown in a top view in Fig. 19 and as a floor member manufactured therefrom in an axonometric view in Fig. 18.

As depicted in Fig. 19, in its top view the vehicle floor member preform is a structure resembling an annular structure, made from a front frame portion 101, a rear frame portion 102 arranged opposite, and from two side frame portions 103 extending between the front frame portion 101 and the rear frame portion 102. The annular structure thus made defines a storage opening which in final realizations of electric vehicles is typically a place for storing electric vehicle batteries. As can be seen in Fig. 19, a front bumper portion 104 extends from the front frame portion 101 and a rear bumper portion 105 extends from the rear frame portion 102. In this embodiment, both the front bumper portion 104 and the rear bumper portion 105 are annular structures defining rectangular inner openings. Although in this embodiment the front bumper portion 104 and the rear bumper portion 105 are identical in terms of their construction and geometry, it is not a limitation to the scope of the invention and in alternative embodiments both the front bumper portion 104 and the rear bumper portion 105 may have different constructions.

The above listed components of the vehicle floor member preform are connected with each other and form an integral portion made of a metal sheet such as steel sheet, defining an inner wall 106 and an outer wall 107 (see for example Fig. 33, which is a longitudinal cross section of this embodiment of the vehicle floor member).

However, it should be emphasized that the sheet thickness of the vehicle floor member preform is not a limitation to the scope of the invention, and in alternative embodiments of the invention it is possible to use a metal sheet having a different thickness and made of a different material. The notions of the inner wall 106 and the outer wall 107 are conventional and are intended to denote, respectively, the inner side and the outer side of the vehicle in which the vehicle floor member of the invention is used. The inner wall 106 and the outer wall 107 are arranged in alignment (on a plane) with respect to each other while providing a gap forming a closed empty inner space of the vehicle floor member preform. On one of the walls 106, 107, there is a valve element 108 arranged, which allow fluid communication with the inner space formed between the walls 106, 107 of the vehicle floor member preform.

The valve element 108 is a pneumatic or hydraulic connection and allows a leakproof fastening of a supply duct from an external source of pressurized fluid. In some embodiments of the invention, the valve element 108 may be a valve, particularly a non-return valve. The location of the valve element 108 is not a limitation to the scope of the present invention, and thus the valve element 108 may be arranged in any location on the metal sheet, on condition that a connection with the inner space of the vehicle floor member preform is allowed.

In this embodiment, the outer edges and the inner edges (from the side of the storage opening) of the floor member preform are sealed with a seal 112, forming a closed hermetic empty inner space of the vehicle floor member preform.

The sealing is performed on the edges of the metal sheet forming the walls 106, 107 of the vehicle floor member preform after they have been matched with each other. In this embodiment, the sealing is thus performed on all the circumferential edges of the matched walls 106, 107 of the vehicle floor member preform. In this embodiment, the sealing was performed by means of welding the corresponding edges together, forming inter alia circumferential welds. By sealing all of the above-listed edges, a leakproof hermetic inner space is formed in the vehicle floor member preform. The type of seal 112 is in this case not a limitation to the scope of the invention, and it is possible in alternative embodiments to use any type of seal 112, on condition that a leakproof inner space is formed in the vehicle floor member preform, by means for example of pressure welding, soldering, gluing, bending or pressing.

The method for manufacturing the vehicle floor member according to one of the embodiments of the invention comprises a step in which a vehicle floor member preform, as defined in this embodiment, is provided. In the case when the provided vehicle floor member preform does not have all of its circumferential edges connected and sealed, the next step comprises the sealing of the unconnected edges of the vehicle floor member preform with the seal 112 for forming a closed hermetic empty inner space of the vehicle floor member preform. As mentioned above, the seal 112 may be realized in any known fashion which ensures that a leakproof inner space is formed.

In the next step, an external source of fluid under pressure is connected to the valve element 108 through the supply duct. In this embodiment, the fluid is air, the source of fluid under pressure is a compressor, and the supply duct together with the valve element 108 form a pneumatic connection. The type of the external source of fluid under pressure and of the connection equipment is not a limitation to the scope of this invention and in alternative embodiments it is possible to use fluid in the form of water, fluid cement, machine oil, fluid plastic such as a one-, two- or three-component foam (e.g. a flex 140 type), flowable natural material (such as liquid rubber) etc. together with the connection equipment and the source of fluid under pressure appropriate for those fluids. The less compressible the fluid is, the more controlled the deformation conditions of the vehicle floor member preform are.

In the next step of the method for manufacturing the vehicle floor member according to the invention, fluid under a defined pressure is delivered to the sealed inner space of the vehicle floor member preform. The technology of introducing fluid under pressure into closed sealed chamber elements made of sheet metal for their deformation and providing them with the final form is known inter alia from patent application No. EP2110189A1. As a result of delivering fluid under pressure into the inner space of the vehicle floor member preform, the walls 106, 107 of the vehicle floor member preform are deformed, as best illustrated in Fig. 33, which shows the longitudinal cross-section of the vehicle floor member manufactured from the vehicle floor member preform. As can be observed, the walls 106, 107 of the vehicle floor member preform are significantly deformed. Importantly, the vehicle floor member according to the present embodiment of the invention has various geometrical dimensions in the front bumper portion 104, in the front frame portion 101, in the rear frame portion 102 and in the rear bumper portion 105. The selection of these geometrical dimensions is dictated by the requirements used with respect both to the safety parameters, i.e. the rigidity and the strength of the structure, and forming of controlled crumble zones, and to the geometrical dimensions for the monocoque body structure. These geometrical dimensions may be freely changed as necessary and adjusted to particular applications.

Note should be taken that although the introduction of fluid under pressure into the inner space of the vehicle floor member preform is performed in cold technology (i.e. in room temperature), it is not a limitation to the scope of this invention, and in alternative embodiments the process may be performed in elevated or high temperatures.

In one embodiment of the invention, the step of introducing fluid under pressure was performed with the following process parameters:

- process temperature: 20 °C,

-working pressure: 2 bars,

- deformation time: 1 minute until pressure is equalized in the vehicle side frame preform,

- pressure hold time: 30 seconds,

- total deformation time: 1.5 min.

Example 7

A further embodiment of this invention is illustrated in a top view in Fig. 20, which shows the vehicle floor member preform.

In general, the vehicle floor member preform, as well as the vehicle floor member manufactured therefrom, is a structure substantially similarto the structure of the vehicle floor member preform and to the structure of the vehicle floor member shown in Example 6, and therefore similarstructural elements will not be repeated for the clarity of this disclosure.

Importantly, unlike in Example 6, the vehicle floor member preform shown in Fig. 20 (as well as the corresponding vehicle floor member) is manufactured from a metal sheet, which does not have a uniform thickness across the entire surface area of the vehicle floor member preform, but rather it has regions of various thicknesses, connected with each other and forming a "patchwork" type structure.

As shown in Fig. 20, the floor member preform is made of three regions having various thicknesses of the material sheet (in this embodiment it is a stainless steel sheet), schematically indicated with respective section lines. In this embodiment, the region having a first thickness being 2 mm is indicated with horizontal lines and includes the front bumper portion 104 and the rear bumper portion 105, the region having a second thickness being 1.5 mm is indicated with diagonal lines and includes the side frame portion 103, while the region having a third thickness being 1.2 mm is indicated with vertical lines and includes the front frame portion 101, the rear frame portion 102 and frame longitudinal ribs 114.

As a result, the inner wall 106 and the outer wall 107 are metal sheets which have varying thicknesses in individual parts of the vehicle floor member (as well as of the corresponding vehicle floor member preform). Owing to the use of the patchwork-type structure, the final vehicle floor member was given desired functional characteristics manifested in the increased strength and rigidity in the regions having increased sheet thickness. Importantly, the structure of the inner wall 106 and of the outer wall 107 is an integrated structure including regions of smaller and greater thickness of the metal sheet. The inner wall 106 and or the outer wall 107 having regions of various thickness may be obtained with any method known in the art, comprising in a non-limiting manner selective press forming, rolling and joining of sheets having different thickness, for example by welding. Moreover, unlike in Example 6, the vehicle floor member preform of this embodiment comprises at least frame longitudinal ribs 114 extending between the front frame portion 101 and the rear frame portion 102 and dividing the storage opening. The frame longitudinal ribs 114 extend substantially parallel with respect to the corresponding side frame portions 103 and in this embodiment they are members integrated with the material of the remaining portions of the vehicle floor member preform. However, it should be noted that in alternative embodiments the longitudinal ribs 114 may be structures independent with respect to the remaining portions of the vehicle floor member preform, which are mounted to the respective regions of the front frame portion 101 and of the rear frame portion 102 (as illustrated for example in Figs. 21, 23 and 25), being simultaneously additional reinforcements for the structure of the final vehicle floor member. The type of the connection between the frame longitudinal rib 114 and the corresponding portions of the floor member preform is not a limitation to the scope of the invention and may be any connection technology known in the art, such as pressure welding, welding, bolting, crimping, gluing, etc. Importantly, the number of the used frame longitudinal ribs 114 is not limited to two either and in alternative embodiments it is possible to use a smaller or a greater number of longitudinal ribs 114 for obtaining desired technical properties of the vehicle floor member. For example Fig. 26 shows a floor member preform comprising three frame longitudinal ribs 114.

In the case when the longitudinal rib 114 is a member separate with respect to the other portions of the floor member preform, it may be a member which copies the structure of the other structural members of the floor member and which is provided with a separate valve element 108 for introducing fluid under pressure into its inner space.

In a further alternative embodiment of the invention, shown in Fig. 26 and in the corresponding cross section of Fig. 35, the vehicle floor member preform (as well as the corresponding vehicle floor member) is manufactured, unlike in Example 6, from a metal sheet, which has regions made of various materials, connected with each other and forming a "material patchwork" type structure. As shown in Fig. 26, the floor member preform is manufactured from three regions made of different materials (in this embodiment it is a stainless steel sheet, a carbon steel sheet and a black steel sheet), schematically indicated with respective line patterns. In this embodiment, the region made of the first material (material 1) is indicated with diagonal lines and includes the front bumper portion 104, the rear bumper portion 105 and the side frame portions 103, the region made of the second material (material 2) is indicated with checkered lines and includes the central frame longitudinal rib 114, the front frame portion 101 and the rear frame portion 102, while the region made of the third material (material 3) is indicated with dots and includes the outer frame longitudinal ribs 114.

As a result, the inner wall 106 and the outer wall 107 are metal sheets which have varying materials in individual parts of the vehicle floor member (as well as of the corresponding vehicle floor member preform). Owing to the use of the material patchwork-type structure, the final vehicle floor member was given desired functional characteristics manifested in the increased strength and rigidity in the regions in which a material of such characteristics is present. Importantly, the structure of the innerwall 106 and of the outer wall 107 is an integrated structure including regions made of different material. The inner wall 106 and/or the outer wall 107 having regions made of different material may be obtained with any method known in the art, comprising in a non-limiting manner joining of sheets made of different material for example by welding, pressure welding, soldering or gluing.

Example 8

A further embodiment of this invention is illustrated in Fig. 21, which shows a top view of the floor member.

In general, the vehicle floor member preform, as well as the vehicle floor member manufactured therefrom, is a structure substantially similarto the structure of the vehicle floor member preform and to the structure of the vehicle floor member shown in Examples 6 and 7, and therefore similar structural elements will not be repeated for the clarity of this disclosure.

Unlike in Examples 6 and 7, in the embodiment illustrated in Fig. 21 the floor member additionally comprises a reinforcing pillar 116 in the region of the front bumper portion 104 and of the rear bumper portion 105. The first reinforcing pillar 116 extends from the outer portion of the front bumper portion 104 to the front frame portion 101, and the second reinforcing pillar 116 extends from the outer portion of the rear bumper portion 105 to the rear frame portion 102. The number and the geometry, as well as the arrangement of the reinforcing pillars 116 within the front bumper portion 104 and/or the rear bumper portion 105 are not a limitation to the scope of this invention, and in alternative embodiments it is possible to use a greater or a smaller number of reinforcing pillars 116, arranged in different geometries. Analogical structures of reinforcing pillars 116 are shown in embodiments illustrated in Figs. 22, 23 and 28, the pillars being members integrated with the material of the other portions of the vehicle floor member preform. However, it should be noted that in alternative embodiments the reinforcing pillars 116 may be structures independent with respect to the remaining portions of the vehicle floor member preform, which are mounted to the respective regions of the front frame portion 101 and the outer portion of the front bumper portion 104and/orthe rearframe portion 102 and the outer portion of the rear bumper portion 105 (as illustrated for example in Figs.24 and 25), being simultaneously additional reinforcements for the structure of the final vehicle floor member. The type of the connection between the reinforcing pillar 116 and the corresponding portions of the floor member preform is not a limitation to the scope of the invention and may be any connection technology known in the art, such as pressure welding, welding, bolting, crimping, gluing, etc. Importantly, the number of the used reinforcing pillars 116 is not limited to that shown in the embodiments and illustrated in the figures either and in alternative embodiments it is possible to use a smaller or a greater number of reinforcing pillars 116 for obtaining desired technical properties of the vehicle floor member.

In the case when the reinforcing pillar 116 is a member separate with respect to the other portions of the floor member preform, it may be a member which copies the structure of the other structural members of the floor member and which is provided with a separate valve element 108 for introducing fluid under pressure into its inner space.

Importantly, the floor member shown in Fig. 21 has flattened regions 109 on the inner wall 106 and on the outer wall 107, wherein the flattened regions 109 have a substantially flat outer surface. The flattened regions 109 allow an additional adjustment of the technical parameters of individual vehicle floor member portions and also are mounting regions for additional final equipment of the vehicle.

The flattened regions 109 can be obtained by using the method for manufacturing the vehicle floor member according to another embodiment of the invention. Unlike in the method for manufacturing the vehicle floor member shown in Example 6, in this embodiment of the method for manufacturing the floor member, the step of introducing fluid under pressure into the inner space of the vehicle floor member preform is preceded by placing the vehicle floor member preform between the pressure plates 113 so that the pressure plates 113 are in contact with the walls 106, 107 of the vehicle floor member preform, as illustrated in Fig. 4. The pressure plates 113 may be the working elements of a mechanical press. In this case, a controlled force may be applied to the pressure plates 113, particularly in the direction towards the vehicle floor member preform. In the step of delivering fluid under pressure into the sealed inner space of the vehicle floor member preform, the vehicle floor member preform is kept between the pressure plates 113. As a result, the vehicle floor member parts manufactured with this method have flattened regions 109 in the desired vehicle floor member regions (where the linings of the pressure plates 113 were applied). The cross section of Fig. 32A shows the vehicle floor member with a region deformed in a free manner (without the use of the pressure plates 113 - the central members) and with a region deformed with the use of the pressure plates 113 (the outer members), having flattened regions 109. In turn, the cross section of Fig. 32B shows the vehicle floor member with a region deformed with the use of the pressure plates 113. The manufacturing method leading to obtaining a structure as illustrated in Fig. 32A is realized in a system shown in Fig. 5 (for simplification, only half of the vehicle floor member is shown), where one (left) vehicle floor member portion is not in contact with the linings of the pressure plates 113 and may be deformed in a free manner, while the second (right) vehicle floor member portion comprises walls being in contact with the pressure plates 113. It is thus possible to provide desired locations with mounting areas for vehicle functional equipment and to locally modify the technical characteristics of the vehicle floor member, such as the rigidity, the strength of the structure, or to form controlled crumble zones. In turn Fig. 33 shows a longitudinal cross section of the vehicle floor member with regions deformed in a free manner (without the use of the pressure plates 113), the shown regions having different geometry, including different wall 106, 107 thickness and, after the deformation, also different vehicle floor member region thickness. The longitudinal cross section of Fig. 33 corresponds to the vehicle floor member formed from the vehicle floor member preform shown in Fig. 19.

Example 9

A further embodiment of this invention is illustrated in Fig. 27, which shows a top view of the vehicle floor member without the outer wall 107 and showing the inner structures of the vehicle floor member.

In general, the vehicle floor member preform, as well as the vehicle floor member manufactured therefrom, is a structure substantially similarto the structure of the vehicle floor member preform and to the structure of the vehicle floor member shown in Examples 6, 7 and 8, and therefore similar structural elements will not be repeated for the clarity of this disclosure.

Unlike in the previous embodiments, the floor member shown in the embodiment illustrated in Fig. 27 additionally comprises a frame transverse rib 115 extending between the frame longitudinal ribs 114 located in the vicinity of the side frame portion 103. The frame transverse rib 115 extends substantially perpendicular with respect to the corresponding frame longitudinal ribs 114 and in this embodiment it is a member integrated with the material of the remaining portions of the vehicle floor member preform. However, it should be noted that in alternative embodiments the transverse rib 115 may be a structure independent with respect to the remaining portions of the vehicle floor member preform (not shown), being mounted to the respective regions of the longitudinal ribs 114 or the side frame portion 103, and being simultaneously an additional reinforcement for the structure of the final vehicle floor member. The type of the connection between the frame transverse rib 115 and the corresponding portions of the floor member preform is not a limitation to the scope of the invention and may be any connection technology known in the art, such as pressure welding, welding, bolting, crimping, gluing, etc. Importantly, the number of the used frame transverse ribs 115 is not limited to one either and in alternative embodiments it is possible to use a smaller or a greater number of transverse ribs 115 for obtaining desired technical properties of the vehicle floor member. For example Fig. 28 shows a floor member comprising four frame transverse ribs 115, wherein the frame transverse ribs 115 extend between the side frame portion 103 and the frame longitudinal rib 114 located in the vicinity. In the case when the transverse rib 115 is a member separate with respect to the other portions of the floor member preform, it may be a member which copies the structure of the other structural members of the floor member and which is provided with a separate valve element 108 for introducing fluid under pressure into its inner space.

As depicted in Fig. 27, unlike in the vehicle floor member preform and in the corresponding vehicle floor member according to the previous embodiments, the vehicle floor member according to this embodiment comprises additional inner structures in the form of inner pockets 110. The inner pockets 110 are arranged in the gap between the inner wall 106 and the outer wall 107, as best illustrated in the cross section of Fig. 34. The inner pocket 110 shown in Fig. 27 is a leakproof hermetic structure with fluid communication through the valve element 108 which passes through the inner wall 106 or through the outer wall 107 of the vehicle floor member while the inner space of the vehicle side frame itself is kept sealed. The inner pocket 110 may be formed analogically to the floor member preform, i.e. from metal sheets connected with each other and sealed on the edges. In alternative embodiments, the inner pocket 110 may be formed from other materials which provide hermetic tightness to the container formed inside and which include, in a non-limiting manner, textile materials.

The embodiment of the vehicle floor member illustrated in Fig. 27 shows two inner pockets 110, wherein the first inner pocket 110 extends partially through the front bumper portion 104, the side frame portion 103 and partially through the rear bumper portion 105. The second inner pocket 110 is arranged on the opposite side of the vehicle floor member, being a mirror reflection of the first inner pocket 110.

The inner pocket 110 used in the vehicle floor member produces different results, depending on its purpose. In this embodiment, the right inner pocket 110 is made from a sheet of carbon steel, wherein the entire structure of the vehicle floor member is made from a sheet of stainless steel. Carbon steel has greater hardness and strength than stainless steel, and therefore the inner pocket 110 made therefrom is an element which increases the strength of the vehicle floor member, providing it with desired technical properties. Additionally, the right inner pocket 110 is deformed by fluid (air) introduced into its hermetic inner space after the vehicle floor member has been formed (by deforming the preform), allowing additional local deformations to be made in the already formed vehicle floor member and allowing the geometry of the vehicle floor member to be adjusted to a desired shape.

In the embodiment shown in Fig. 27, the left inner pocket 110 is made of a textile material (for example kevlar), forming a compartment in which a filler 111 is present (as illustrated in Fig. 34). In this embodiment, the filler 111 is non- Newtonian fluid which allows the formation of adequately adjusted shock- absorbing zones. The inner pocket 110 with the non-Newtonian fluid may be a separate structure introduced into the vehicle floor member preform. Alternatively, the inner pocket 110 may be filled with the non-Newtonian fluid after the vehicle floor member has been formed. In the latter case, the inner pocket 110 requires a valve element 108 which will serve to introduce the filler 111.

Importantly, the type of the filler 111 present in the inner pocket 110 is not limited to the non-Newtonian fluid, and in alternative embodiments the fillers 111 may be such that ensure desired technical properties (for example soundproofing level), and may include a one-, two- or three-component foam. Example 10

A further embodiment of this invention is illustrated in Fig. 29, which shows an axonometric view of the vehicle floor system. In this embodiment, the vehicle floor system comprises two vehicle floor members of the invention, disclosed in the previous embodiments. The vehicle floor members are arranged in a stack one on top of another, with an appropriate gap retained between them. In the embodiment illustrated in Fig. 29, the lower vehicle floor member is a vehicle floor member shown in Fig. 20, and the upper vehicle floor member is a vehicle floor member shown in Fig. 21. It should be noted, however, that the vehicle floor system is not limited to the structure shown in Fig. 29 and in alternative embodiments it may be a combination of any of the vehicle floor members according to the present invention, especially of the members presented in the previous embodiments, as well as of more than two members. One of the alternative embodiments of the vehicle floor system is shown in Fig. 30, wherein the lower vehicle floor member is a vehicle floor member shown in Fig. 24, and the upper vehicle floor member is a vehicle floor member shown in Fig. 19. Unlike in the vehicle floor system shown in Fig. 29, the embodiment of Fig. 30 additionally comprises side plates 117 connected with the corresponding edges of individual vehicle floor members and ensuring that the vehicle floor members are kept at a defined distance with respect to each other. In the embodiment shown in Fig. 30, there are six side plates 117, two of them being located on the opposite sides of the corresponding front bumper portions 104, two of them being located on the opposite sides of the corresponding side frame portions 103, and the remaining two being located on the opposite sides of the corresponding rear bumper portions 105.

In the embodiment shown in Fig. 30, the side plates 117 are members deformed by a fluid under pressure introduced into their inner spaces, i.e. they are manufactured in the technology of the other portions of the vehicle floor member according to the invention. Fig. 31 shows the vehicle floor system of Fig. 30 with the installed suspension components.

Example 11

The vehicle floor member manufactured using the method according to the invention was subjected to comparative tests (based on numerical calculations) with a vehicle floor member manufactured using traditional technology.

Figs. 36 - 39 show displacement maps (in the Z axis for the case of bending and rotation in the X axis for the case of torsion) in the vehicle floor members in two load states. The analysis was performed for the cases of twisting and bending the vehicle floor members. Identical boundary conditions were kept for all of the numerical models. In the case of twisting, all floor members were secured in the rear portion (in the center of the rear bumper portion 105), and the front was twisted by an angle equal to 1°. In the case of bending, all frames were supported in two points (in the center of the front bumper portion 104 and of the rear bumper portion 105), and a force corresponding to the mass of 100 N was applied in the central portion (in the center of the side frame portion 103). In the stress distribution maps, the legend for the corresponding load cases (twisting/bending) is presented in an identical scale. The values of rotation at twisting, expressed in degrees, correspond to the loading with the twisting moment M = 100 Nm. The material used in the simulations was steel, Young's modulus E = 206.94 GPa, Poisson ratio v = 0.288, density p = 7829 kg/m ³ .

Figs. 36 and 37 are displacement maps made for a floor member according to the invention. Figs. 38 and 39 are displacement maps made for a floor member manufactured in the traditional technology, using classic rectangular profiles.

The calculated strength parameters are presented in Table 3.

Table 3 - Comparison of vehicle floor member strength parameters As demonstrated in Table 3, the floor member according to the invention is lighter than the floor member made from standard profiles (for the sheet thickness of 1.0 mm regarding the 60x20x1.5 mm rectangular profile and for the sheet thickness of 1.2 mm regarding the 70x20x1.5 mm rectangular profile) while showing similar torsional rigidity parameters and significantly higher bending rigidity parameters.

Example 12

Fig. 40 shows an axonometric view of a vehicle unibody frame in which two vehicle frame longitudinal members were used, according to the embodiment of the invention. The embodiment in the form of a vehicle frame longitudinal member preform is shown in a side view in Fig. 41 and is also shown in the form of a vehicle frame longitudinal member manufactured therefrom in a side view in Fig. 42, in an axonometric view in Fig. 43 and in a cross-sectional view in Fig. 44.

As illustrated in Fig. 41, the vehicle frame longitudinal member preform is in its side view a longitudinal structure comprising a front portion 201 configured to to be arranged in the front portion of the vehicle body frame, a central portion 202, arranged in the central region of the vehicle body frame, and the rear portion 203, configured to be arranged in the rear portion of the vehicle body frame. A schematic arrangement of the vehicle frame longitudinal member according to the embodiment with respect to the vehicle body frame is shown in Fig. 42 and in Fig. 43. The vehicle frame longitudinal member preform shown in Fig. 41 comprises the central portion 202, which is moved towards the bottom of the vehicle body frame with respect to the front portion 201. In this embodiment, the rear portion 203 is substantially aligned with the front portion 201. Between the front portion 201 and the central portion 202, there may be defined a transition region with a portion of the vehicle frame longitudinal member preform inclined in the bottom direction. Analogically, between the rear portion 203 and the central portion 202, there may be defined a transition region with a portion of the vehicle frame longitudinal member preform inclined in the bottom direction. In the vicinity of the ends of the central portion 202, there are also located two bottom protrusions being depressions in longitudinal direction of the vehicle frame longitudinal member preform. The bottom protrusions are regions protruding lowermost of the vehicle frame longitudinal member preform and they function as connection members for connecting the floor members being part of the vehicle floor member system.

The above listed components of the vehicle frame longitudinal member preform are connected with each other and form an integral portion made of a metal sheet such as steel sheet 2 mm in thickness, defining an inner wall 206 and an outer wall 207 (see for example Fig. 44, which is a cross section of the vehicle frame longitudinal member manufactured from the said vehicle frame longitudinal member preform of Fig. 41). The thickness of the metal sheet is not limited to the value provided above and in alternative embodiments it is possible to use metal sheets having thicknesses within the range from 1 mm to 5 mm, depending on the structural and strength requirements of the final vehicle frame longitudinal member.

It should be emphasized that the sheet thickness of the vehicle frame longitudinal member preform is not a limitation to the scope of the invention, and in alternative embodiments of the invention it is possible to use a metal sheet having a different thickness and made of a different material. The notions of the inner wall 206 and the outer wall 207 are conventional and are intended to denote, respectively, the inner side and the outer side of the vehicle in which the vehicle frame longitudinal member of the invention is used. The inner wall 206 and the outer wall 207 are arranged in alignment (on a plane) with respect to each other while providing a gap forming a closed empty inner space of the vehicle frame longitudinal member preform. On one of the walls 206, 207, there is a valve element 208 arranged, which allow fluid communication with the inner space formed between the walls 206, 207 of the vehicle frame longitudinal member preform.

The valve element 208 is a pneumatic or hydraulic connection and allows a leakproof fastening of a supply duct from an external source of pressurized fluid. In some embodiments of the invention, the valve element 208 may be a valve, particularly a non-return valve. The location of the valve element 208 is not a limitation to the scope of the present invention, and thus the valve element 208 may be arranged in any location on the metal sheet, on condition that a connection with the inner space of the vehicle frame longitudinal member preform is allowed.

In this embodiment, the outer edges of the vehicle frame longitudinal member preform are sealed with a seal 212, forming a closed hermetic empty inner space of the vehicle frame longitudinal member preform.

The sealing is performed on the edges of the metal sheet forming the walls 206, 207 of the vehicle frame longitudinal member preform after they have been matched with each other. In this embodiment, the sealing is thus performed on all the circumferential edges of the matched walls 206, 207 of the vehicle frame longitudinal member preform. In this embodiment, the sealing was performed by means of welding the corresponding edges together, forming inter alia circumferential welds. By sealing all of the above-listed edges, a leakproof hermetic inner space is formed in the vehicle frame longitudinal member preform. The type of seal 212 is in this case not a limitation to the scope of the invention, and it is possible in alternative embodiments to use any type of seal 212, on condition that a leakproof inner space is formed in the vehicle frame longitudinal member preform, by means for example of pressure welding, soldering, gluing, bending or pressing.

The method for manufacturing the vehicle frame longitudinal member according to one of the embodiments of the invention comprises a step in which a vehicle frame longitudinal member preform, as defined in this embodiment, is provided. In the case when the provided vehicle frame longitudinal member preform does not have all of its circumferential edges connected and sealed, the next step comprises the sealing of the unconnected edges of the vehicle frame longitudinal member preform with the seal 212 for forming a closed hermetic empty inner space of the vehicle frame longitudinal member preform. As mentioned above, the seal 212 may be realized in any known fashion which ensures that a leakproof inner space is formed.

In the next step, an external source of fluid under pressure is connected to the valve element 208 through the supply duct. In this embodiment, the fluid is air, the source of fluid under pressure is a compressor, and the supply duct together with the valve element 208 form a pneumatic connection. The type of the external source of fluid under pressure and of the connection equipment is not a limitation to the scope of this invention and in alternative embodiments it is possible to use fluid in the form of water, fluid cement, machine oil, fluid plastic such as a one-, two- or three-component foam (e.g. a flex 140 type), flowable natural material (such as liquid rubber) etc. together with the connection equipment and the source of fluid under pressure appropriate for those fluids. The less compressible the fluid is, the more controlled the deformation conditions of the vehicle frame longitudinal member preform are.

In the next step of the method for manufacturing the vehicle frame longitudinal member according to the invention, fluid under a defined pressure is delivered to the sealed inner space of the vehicle frame longitudinal member preform. The technology of introducing fluid under pressure into closed sealed chamber elements made of sheet metal for their deformation and providing them with the final form is known inter alia from patent application No. EP2110189A1. As a result of delivering fluid under pressure into the inner space of the vehicle frame longitudinal member preform, the walls 206, 207 of the vehicle frame longitudinal member preform are deformed, as best illustrated in Fig. 44, which shows the cross-section of the vehicle frame longitudinal member manufactured from the vehicle frame longitudinal member preform. As can be observed, the walls 206, 207 of the vehicle frame longitudinal member preform are significantly deformed. Importantly, the vehicle frame longitudinal member according to the present embodiment of the invention has different geometrical dimensions in the front portion 201, in the central portion 202 and in the rear portion 203. The selection of these geometrical dimensions is dictated by the requirements used with respect both to the safety parameters, i.e. the rigidity and the strength of the structure, and forming of controlled crumble zones, and to the geometrical dimensions for the monocoque body structure. These geometrical dimensions may be freely changed as necessary and adjusted to particular applications.

Note should be taken that although the introduction of fluid under pressure into the inner space of the vehicle frame longitudinal member preform is performed in cold technology (i.e. in room temperature), it is not a limitation to the scope of this invention, and in alternative embodiments the process may be performed in elevated or high temperatures.

In one embodiment of the invention, the step of introducing fluid under pressure was performed with the following process parameters: - process temperature: 20 °C,

-working pressure: 2 bars,

- deformation time: 1 minute until pressure is equalized in the vehicle side frame preform,

- pressure hold time: 30 seconds, - total deformation time: 1.5 min. Example 13

A further embodiment in the form of a vehicle frame longitudinal member preform is shown in a side view in Fig. 45 and is also shown in the form of a vehicle frame longitudinal member manufactured therefrom in a side view in Fig. 46, in an axonometric view in Fig. 47 and in a cross-sectional view in Fig. 48.

In general, the vehicle frame longitudinal member preform, as well as the vehicle frame longitudinal member manufactured therefrom, is a structure substantially similar to the structure of the vehicle frame longitudinal member preform and to the structure of the vehicle frame longitudinal member shown in Example 12, and therefore similar structural elements will not be repeated for the clarity of this disclosure.

Importantly, unlike in Example 12, the vehicle frame longitudinal member preform shown in Fig. 45 (as well as the corresponding vehicle frame longitudinal member) is manufactured from a metal sheet, which does not have a uniform thickness across the entire surface area of the vehicle frame longitudinal member preform, but rather it has regions of various thicknesses, connected with each other and forming a "patchwork" type structure.

As shown in Fig. 45, the vehicle frame longitudinal member preform is made of three regions having various thicknesses of the material sheet (in this embodiment it is a stainless steel sheet), schematically indicated with respective section lines. In this embodiment, the region having a first thickness being 2 mm is indicated with diagonal lines and includes the front portion 201 and a transition portion between the front portion 201 and the central portion 202, the region having a second thickness being 1.5 mm is indicated with dots and includes the front fragment of the central portion 202, while the region having a third thickness being 1.2 mm is indicated with vertical lines and includes the rear fragment of the central portion 202. As a result, the inner wall 206 and the outer wall 207 are metal sheets which have varying thicknesses in individual parts of the vehicle frame longitudinal member (as well as of the corresponding vehicle frame longitudinal member preform). Owing to the use of the patchwork-type structure, the final vehicle frame longitudinal member was given desired functional characteristics manifested in the increased strength and rigidity in the regions having increased sheet thickness. Importantly, the structure of the inner wall 206 and of the outer wall 207 is an integrated structure including regions of smaller and greater thickness of the metal sheet. The inner wall 206 and orthe outer wall 207 having regions of various thickness may be obtained with any method known in the art, comprising in a non limiting manner selective press forming, rolling and joining of sheets having different thickness, for example by welding.

Moreover, unlike in Example 12, the vehicle frame longitudinal member preform of this embodiment is without the rear portion, and thus comprises only the front portion 201 and the central portion 202. A frame longitudinal member manufactured from such a preform is intended for installation in the front and central portions of the vehicle body frame, as best illustrated in a side view of Fig. 46.

Additionally, in its front portion 201, the vehicle frame longitudinal member preform of this embodiment, as well as the vehicle frame longitudinal member manufactured therefrom, have an annular structure 204, which provides connection surfaces for connecting the floor members as well as increased strength and stability of the structure in this region, especially to withstand deformations resulting from an impact from the front. Additionally, by providing annular structures 204 in place of full structures (without an opening), it is possible to reduce the mass of the final vehicle frame longitudinal member.

Moreover, unlike in Example 12, the vehicle frame longitudinal member preform of this embodiment, as well as the vehicle frame longitudinal member manufactured therefrom comprises a transition annular structure 205 in a transition region between the front portion 201 and the central portion 202, as best illustrated in Fig. 45. The purpose of the transition annular structure 205 is to provide connection surfaces for connecting the floor members, as well as increased strength and stability of the structure and reduced mass.

Example 14

A further embodiment in the form of a vehicle frame longitudinal member preform is shown in a side view in Fig. 49 and is also shown in the form of a vehicle frame longitudinal member manufactured therefrom in a side view in Fig. 50, in an axonometric view in Fig. 51 and in a cross-sectional view in Fig. 52.

In general, the vehicle frame longitudinal member preform, as well as the vehicle frame longitudinal member manufactured therefrom, is a structure substantially similar to the structure of the vehicle frame longitudinal member preform and to the structure of the vehicle frame longitudinal member shown in Example 12, and therefore similar structural elements will not be repeated for the clarity of this disclosure.

Unlike in Example 12, in the embodiment illustrated in Fig. 49, the vehicle frame longitudinal member preform additionally comprises a central annular structure

209 located in the region of the central portion 202. Moreover, in the central portion 202 there are located two reinforcing ribs 210 extending through the opening defined by the central annular structure 209 and connecting the opposite longitudinal regions of the central annular structure 209.

The number and the geometry, as well as the arrangement of the reinforcing ribs

210 within the central annular structure 209 are not a limitation to the scope of this invention, and in alternative embodiments it is possible to use a greater or a smaller number of reinforcing ribs 210, arranged in different geometries. However, it should be also noted that in alternative embodiments the reinforcing ribs 210 may be structures independent with respect to the remaining portions of the vehicle frame longitudinal member preform, being mounted to the respective regions of the central annular structure 209, and being simultaneously an additional reinforcement for the structure of the final vehicle frame longitudinal member. The type of the connection between the reinforcing rib 210 and the corresponding portions of the vehicle frame longitudinal member preform is not a limitation to the scope of the invention and may be any connection technology known in the art, such as pressure welding, welding, bolting, crimping, gluing, etc. Importantly, the number of the used reinforcing ribs 210 is not limited to that shown in the embodiments and illustrated in the figures either and in alternative embodiments it is possible to use a smaller or a greater number of reinforcing ribs 210 for obtaining desired technical properties of the vehicle frame longitudinal member.

In the case when the reinforcing rib 210 is a member separate with respect to the other portions of the vehicle frame longitudinal member preform, it may be a member which copies the structure of the other structural members of the vehicle frame longitudinal member and which is provided with a separate valve element 208 for introducing fluid under pressure into its inner space.

In a further alternative embodiment of the invention, shown in Figs. 50 and 51 and in the corresponding cross section of Fig. 52, the vehicle frame longitudinal member preform (as well as the corresponding vehicle frame longitudinal member) is manufactured, unlike in Example 12, from a metal sheet, which has regions made of various materials, connected with each other and forming a "material patchwork" type structure. As shown in Fig. 49, the vehicle frame longitudinal member preform is manufactured from three regions made of different materials (in this embodiment it is a stainless steel sheet, a carbon steel sheet and a black steel sheet), schematically indicated with respective line patterns. In this embodiment, the region made of the first material (material 1) is indicated with diagonal lines and includes the front portion 201, the region made of the second material (material 2) is indicated with dots and includes the central portion 202, while the region made of the third material (material 3) is indicated with horizontal lines and includes the rear portion 203.

As a result, the inner wall 206 and the outer wall 207 are metal sheets which have varying materials in individual parts of the vehicle frame longitudinal member (as well as of the corresponding vehicle frame longitudinal member preform). Owing to the use of the material patchwork-type structure, the final vehicle frame longitudinal member was given desired functional characteristics manifested in the increased strength and rigidity in the regions in which a material of such characteristics is present. Importantly, the structure of the inner wall 206 and of the outer wall 207 is an integrated structure including regions made of different material. The inner wall 206 and/or the outer wall 207 having regions made of different material may be obtained with any method known in the art, comprising in a non-limiting manner joining of sheets made of different material for example by welding, pressure welding, soldering or gluing.

Example 15

A further embodiment in the form of a vehicle frame longitudinal member preform is shown in a side view in Fig. 53 and is also shown in the form of a vehicle frame longitudinal member manufactured therefrom in a side view in Fig. 54 and 55, in an axonometric view in Fig. 56 and in a cross-sectional view in Fig. 57.

In general, the vehicle frame longitudinal member preform, as well as the vehicle frame longitudinal member manufactured therefrom, is a structure substantially similar to the structure of the vehicle frame longitudinal member preform and to the structure of the vehicle frame longitudinal member shown in Example 12, and therefore similar structural elements will not be repeated for the clarity of this disclosure. Unlike in Example 12, in the embodiment illustrated in Fig. 53, the vehicle frame longitudinal member preform comprises two end annular structures 204 located respectively in the front portion 201 and in the rear portion 203. The purpose of the end annular structures 204 is to provide connection surfaces for connecting the floor members, as well as increased strength and stability of the structure and reduced mass.

Importantly, the frame longitudinal member shown in Figs. 54 - 57 has flattened regions 211 on the innerwall 206 and on the outer wall 207, wherein the flattened regions 211 have a substantially flat outer surface. The flattened regions 211 allow an additional adjustment of the technical parameters of individual vehicle frame longitudinal member portions and also are mounting regions for additional final equipment of the vehicle. In particular it is possible to control (especially to reduce) the width dimension of the vehicle frame longitudinal member to meet particular structural needs. The flattened regions 211 can be obtained by using the method for manufacturing the vehicle frame longitudinal member according to a further embodiment of the invention. Unlike in the method for manufacturing the vehicle frame longitudinal member shown in Example 12, in this embodiment of the method for manufacturing the frame longitudinal member, the step of introducing fluid under pressure into the inner space of the vehicle frame longitudinal member preform is preceded by placing the vehicle frame longitudinal member preform between the pressure plates 213 so that the pressure plates 213 are in contact with the walls 206, 207 of the vehicle frame longitudinal member preform, as illustrated in Fig. 4. The pressure plates 213 may be the working elements of a mechanical press. In this case, a controlled force may be applied to the pressure plates 213, particularly in the direction towards the vehicle frame longitudinal member preform. In the step of delivering fluid under pressure into the sealed inner space of the vehicle frame longitudinal member preform, the vehicle frame longitudinal member preform is kept between the pressure plates 213. As a result, the vehicle frame longitudinal member parts manufactured with this method have flattened regions 211 in the desired vehicle frame longitudinal member regions (where the linings of the pressure plates 213 were applied). The cross section of Fig. 57 shows the vehicle frame longitudinal member, with a region deformed with the use of the pressure plates 213, having flattened regions 211. The manufacturing method leading to obtaining a structure as illustrated in Fig. 57 is realized in a system shown in Fig. 5, where one vehicle frame longitudinal member portion is not in contact with the linings of the pressure plates 213 and may be deformed in a free manner, while the second vehicle frame longitudinal member portion comprises walls being in contact with the pressure plates 213. It is thus possible to provide desired locations with mounting areas for vehicle functional equipment and to locally modify the technical characteristics of the vehicle frame longitudinal member, such as the rigidity, the strength of the structure, or to form controlled crumble zones.

Example 16

The vehicle frame longitudinal member manufactured using the method according to the invention was subjected to comparative tests (based on numerical calculations) with a vehicle frame longitudinal member manufactured using traditional technology. For the purpose of performing the comparative tests, a frame structure comprising frame longitudinal members for the Chevrolet Silverado 1500 (production year 2014) was selected. A model of the vehicle frame based on the Chevrolet Silverado 1500 frame longitudinal members manufactured from components according to traditional technology is shown in Fig. 58, while an analogical model of the vehicle frame based on the frame longitudinal members according to the present invention, manufactured with the method of this invention, is shown in Fig. 59. In turn, Fig. 60 shows a stress distribution map for the structure being the result of torsion testing of the frame modeled in Fig. 59. Identical boundary conditions were kept for all of the numerical models. The applied values of rotation at twisting, corresponded to the loading with the twisting moment M = 100 Nm. The material used in the simulations was steel, Young's modulus E = 206.94 GPa, Poisson ratio = v = 0.288, density p = 7829 kg/m ³ . The individual component members of the frame based on the frame longitudinal members of this invention were made from a metal material sheet having a thickness from 0.8 mm to 2 mm.

The calculated strength parameters are presented in Table 4.

Table 4 - Comparison of the strength parameters of the vehicle frame manufactured from the vehicle frame longitudinal members

As demonstrated in Table 4, the frame based on frame longitudinal members of this invention is lighter than the frame based on frame longitudinal members manufactured from standard profiles while showing more favorable torsional rigidity parameters. In the case of the traditional technology, the frame was constructed from 62 component members, while in the case of the technology of this invention the frame was constructed from 74 component members, 58 of which were members manufactured in the technology consisting in introducing fluid under pressure into closed sealed chamber elements made of sheet metal for their deformation and providing them with the final form.

The LWI (Light Weight Index) parameter shown in Table 4 is a parameter used in the art for comparison purposes and defines the structural efficiency of a structure. Its lower value indicates that a more favorable structural efficiency was obtained. The LWI parameter was defined interalia in Singh, Harry. (2012, August). Mass Reduction for Light-Duty Vehicles for Model Years 2017-2025. (Report No. DOT HS 811666). Example 17

Fig. 61 is an axonometric view of a vehicle body frame being an embodiment of the invention. The shown vehicle body frame was manufactured by connecting two vehicle side frames shown in the previous embodiments in Fig. 2, from two floor members shown in the previous embodiments in Figs. 19 and 20 and from two vehicle frame longitudinal members shown in previous embodiments in Fig. 42. In alternative embodiments, the vehicle body frame may be manufactured from a smaller or greater number of vehicle body frame component members comprising any of the members shown in the previous embodiments of the vehicle side frames, vehicle floor members and vehicle frame longitudinal members.

List of reference numerals:

1- front pillar portion

2 - roof frame portion

3 - rear pillar portion 4 -sill portion

5 - central pillar portion 6-innerwall

7 -outer wall

8 -valve element 9 -flattened region

10- inner pocket

11 - filler

12 - seal 13 - pressure plate

101 - front frame portion

102 - rear frame portion

103 - side frame portion

104 - front bumper portion 105 - rear bumper portion

106- innerwall

107 -outer wall

108 - valve element

109 - flattened region 110- inner pocket

111 -filler

112 -seal

113 - pressure plate 114 -frame longitudinal rib 115 - frame transverse rib

116 - reinforcing pillar 117 - side plate

201 - front portion

202 - central portion

203 - rear portion 204 -end annular structure

205 - transition annular structure

206- innerwall

207 -outer wall 208 - valve element 209 - central annular structure

210- reinforcing rib 211 - flattened region

212 -seal

213 - pressure plate