TECHNICAL FIELD

[0001] The present subject matter relates to a mounting assembly. More particularly, it relates to a mounting assembly for a structural member of a vehicle.

BACKGROUND [0002] Typically, a structural member is designed to bear all applied loads without failure during its intended life. Thus, strength and rigidity are important parameters in a structural design of the structural member. The structural member has varied applications including automobiles, architecture etc. Based on application and its requirements the dimensions, connections can vary. It is observed that improperly designed or fabricated structural member tend to fail with possible serious consequences.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The detailed description is described with reference to an embodiment of a load deck for a multitrack light commercial vehicle with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.

[0004] Fig. 1 illustrates perspective view of the load deck as per embodiment of the present invention.

[0005] Fig. 2 illustrates the bottom view of the load deck and localized perspective view of the primary mount structure and secondary mount structure where few parts are omitted as per embodiment of the present invention.

[0006] Fig. 3 illustrates a partial side view of the multitrack light commercial vehicle and localized exploded perspective view of the multitrack light commercial vehicle respectively where few parts are omitted as per embodiment of the present invention.

[0007] Fig. 4 illustrates the side view of the fabricated unfolded mount structure respectively as per embodiment of the present invention. [0008] Fig. 5 illustrates the flowchart depicting method of fabrication and method of bending of the primary mount structure and secondary mount structure as per embodiment of the present invention.

[0009] Fig. 6 illustrates the perspective view of the primary mount structure and secondary mount structure as per embodiment of the present invention.

[00010] Fig. 7 illustrates a graphical representation showing comparison of proposed mount structure with conventional mount structure.

DETAILED DESCRIPTION

[00011] It is contemplated that the concepts of the present invention may be applied to any type of vehicle employing the similar configuration within the spirit and scope of this invention. Further "front" and "rear", and "left" and "right" referred to in the ensuing description of the illustrated embodiment refer to front and rear, and left and right directions as seen from a rear portion of the load deck and looking forward. Furthermore, a longitudinal axis unless otherwise mentioned, refers to a front to rear axis relative to the load deck, while a lateral axis unless otherwise mentioned, refers generally to a side to side, or left to right axis relative to the load deck. The detailed explanation of the constitution of parts other than the present subject matter which constitutes an essential part has been omitted at suitable places.

[00012] Generally, structural members have varied applications. Based on the applications the structural members experience different stresses. Thus, structural member can have various embodiments based on application, for sake brevity the preferred embodiment i.e. application of structural member in multitrack light commercial vehicle will be discernible from the following further description thereof, set out hereunder.

[00013] As per preferred embodiment, the multitrack light commercial vehicles include vehicles configured to have load deck. The load deck used in general to transport various materials including perishable goods or bulky materials. The multitrack light commercial cargo vehicles are popular because of their multiutility features and less operating cost. As, it is affordable and providing profitable business to buyers in both urban and rural areas. Further, the light commercial trucks provide easy navigation in narrow areas and heavy traffic because of small turning radius.

[00014] It is observed that operator tend to customize the load deck to increase the load deck area which is subject to frequent loading and unloading. This customization affects the vehicles performance and durability of the associated parts. As increased load deck area affects vehicles dynamics and allows overloading beyond prescribed limit. Hence improving the safety of vehicle is always a big challenge for automobile manufacturers.

[00015] It is further observed that the load deck should be mounted at an optimum height from the powertrain assembly for passive cooling of the powertrain and ease of serviceability. Thus, it is important to maintain a higher mounting height of the load deck for such a vehicle.

[00016] Typically, a structural member is sandwiched between the chassis frame structure and load deck. However, the structural member tends to buckle due to increased height which affects the vehicle dynamics. Furthermore, the load deck is subjected to dynamic loading because of forces coming from the wheel assembly. These forces are transferred to the structural member through chassis frame structure. Generally, the chassis frame structure has higher stiffness and strength than the load deck and its associated parts. Thus, the load deck and its associated parts tend to fails under cyclic loading specifically in rugged or unmetalled roads. This is further aggravated in customized load deck usage etc. as opposite reaction forces is experienced by the load deck and its associated parts including the structural member affixed to the load deck. Forces are transferred from the load deck to the chassis frame structure through the structural member.

[00017] In addition to above, different stresses act on the structural member between the load deck and the chassis frame structure. These stresses are developed due to various forces like gravitational acceleration, acceleration caused by transport conditions like sudden braking etc.

[00018] Increased vehicle load and load distribution have significant influence on vehicle performance because they change the centre of gravity towards individual axle which further affects the noise, vibration and harshness performance of the vehicle, also known as NVH performance. Further, frequent high loading beyond engineered payload affects the durability of the structural members between the load deck and the chassis frame structure. Furthermore, the movement of the load on rugged, rough, unmetalled roads in rural areas or during climbing a gradient on the road adds more noise and vibration in the vehicle.

[00019] It is further observed that because of above factors the structural member is subject to deformation. The structure member deformation results into oscillation of load deck. The oscillation of load deck is caused due to deformed structural member. Therefore, the load deck is supported to chassis frame structure in the inclined posture which tend to make it unstable. Thus, accommodated goods may collapse or may fall or fly away in the case where the load deck is provided with no cover or goods are improperly secured.

[00020] To improve stiffness of the structural member and associated NVH performance it is known in the prior arts to add separate reinforcement structures in the structure member. The reinforcement structure includes reinforcement bracket which adds more mass in the structure member. The reinforcement structures improve the stiffness and strength of the structure member but albeit at more cost and weight. Further, the complex design of the structural member includes plurality of brackets or structural members followed by complex manufacturing operation which increases manufacturing time and cost. Complex manufacturing requires special purpose machine (SPM) configured to have customized tools including customized punch and die. Specifically different tools for different profile of brackets or structural member. Further, increased manufacturing time reduces the production rate of the vehicle due to increased assembly time. The reduced production rate further increases the man power cost per vehicle. Consequentially increased manufacturing cost including tooling cost increases overall manufacturing cost of the vehicle.

[00021] In addition to manufacturing cost, the added weight increases overall weight of the load deck assembly and the multitrack light commercial cargo vehicle. [00022] At the same time, it is critical for the multitrack light commercial cargo vehicles to deliver high efficiency in form of the fuel economy/mileage/range. Because increased weight affects the vehicle performance including fuel economy/ mileage/range. So, to reduce the fuel consumption/ current drawn from the battery or fuel cell stack one of the ways is to reduce the structural weight of the vehicle. Thus, overall the design challenge becomes an endless moving target to achieve and a trade-off becomes imminent. Designing a structural member with a right trade-off and selecting the factors to trade-off is where lies the challenge for a design engineer.

[00023] At the same time the automobile manufacturers need to cater to different market segments and users with product offerings and variants meeting demands of respective users. These could involve variants in form of size, capacity of vehicle, range of usage, cost, ease of manufacturing, etc. From manufacturer’s points of view, once a platform product is designed, the product economics would be viable based on the numbers sold. Therefore, it is always a challenge for automobile manufacturer to have vehicle layout and design which can be flexible to cater to the variants and the demands and enable modified versions with minimum changes in the vehicle layout, assembly time, manufacturing set-up etc. Additionally, from convenience of usage and utility space point of view, multi wheel light commercial vehicles with more load deck space have become more popular rather than conventional multi wheeled type configuration. The challenge is further complicated when the vehicle architecture / platform requirement needs to cater to different powertrains like Internal combustion engine (ICE) to an Electric Powertrain or a Hybrid powertrain. Further, to create any alternate variant or upgrades etc.

[00024] So, it is always a challenge for the automobile designer to design a structure member which is more reliable, effective and compact meeting various challenges outlined above and at same time be less costly. As, it is counterintuitive in nature to improve safety of the vehicle without increasing its overall weight of the vehicle. Therefore there is a need for an improved design of a structural member for a vehicle overcoming all above problems & trade-offs as well as overcoming problems of known art.

[00025] Hence, it is an object of the invention to provide an improved and simplified design of the structural member which is also easy to fabricate. [00026] It is yet another objective is to reduce the tooling cost for the manufacturing of the structural member.

[00027] It is yet another object of the present invention to provide the structure member which ensure that a higher pay load & sometimes over rated payload can be transported within the available power. [00028] It is an object of the invention is to provide the structure member adapted to distribute and absorb stresses received at wheels and the load deck.

[00029] Therefore, the present invention relates to a load deck for a multitrack light commercial vehicle. The load deck comprising one or more mount structure. The mount structure is attached between said load deck and a chassis frame structure of said vehicle. Further, the mount structure is configured to have an opening adapted to receive an attachment means to secure said load deck to said chassis frame structure.

[00030] As per one implementation of the invention, said mount structures are attached to the chassis frame structure such that a cushion member is sandwiched between them to isolate the shocks.

[00031] As per one implementation of the invention, said mount structure) comprises a primary mount structure and a secondary mount structure.

[00032] As per one implementation of the invention, said primary mount structure and secondary mount structure configured to have a base portion, said base portion configured to have the opening adapted to receive attachment means e.g. a threaded fastener.

[00033] As per one implementation of the invention, said primary mount structure and secondary mount structure is configured to have at least three side walls extending in vertical direction from the base portion. [00034] As per one implementation of the invention, one of said side walls configured to have side flanges, said side flanges are extending from the peripheral edges of sidewall.

[00035] As per one implementation of the invention, each one of said wall is configured to have an end flange.

[00036] As per one implementation of the invention, said primary mount structure comprises of at least one end flange extending vertically such that it is substantially perpendicular to the base portion.

[00037] As per one implementation of the invention, said secondary mount structure configured to have at least three end flanges parallel to the base portion. [00038] Further, the present invention describes a method of manufacturing of mount structure including fabrication and bending operation.

[00039] In this detailed description we will be briefing on parts that are necessary for complete understanding of this invention.

[00040] Figure 1 illustrates a perspective view of a load deck. The multitrack light commercial cargo vehicle configured to have a front user cabin (not shown), and an open top rear load deck (101). The load deck (101) and passenger cabin (not shown) are mounted on a chassis frame structure (301) (as shown in figure 3) as separate assemblies. The load deck (101) has a flatbed (101a) surrounded by two sidewalls (101b) and a tail gate (101c). The tail gate (101c) is hinged at the rear edge of the flatbed (101a) which is closeable to provide a wall for the cargo area. In preferred embodiment, the side walls (101b) are hinged to the flat bed side edges. [00041] Figure 2 illustrates a bottom view of the load deck (101) with the localized views of mount structures (204, 205). The load deck (101) is configured to have at least two long members (201). The long members (201) are fixedly attached to the lower surface (101L) of the load deck (101). The pair of long members (201) are parallel to each other and extending in a longitudinal direction (Y-Y’) of the load deck (101). Further, the load deck is configured to have first cross members and second cross members. The first cross members (202F) and second cross members (202S) are extending in the lateral direction (C-C’) of the load deck (101). Further, the first cross member (202F) and second cross member (202S) are attached to the lower surface (101L) of the load deck (101) and the long members (201). The first cross member (202F) extends between a peripheral side edges (101LS) of the lower surface (101L) of the load deck (101) and passing through a pair of the long members (201). However, the second cross member (202S) extends between long members (201) and the peripheral side edge (101LS) of the lower surface (101L) of the load deck (101). The second cross members (202S) are fixedly attached to the long members (201) and the lower surface (101L) of the load deck (101). As per preferred embodiment the cross members (202) and the long members (201) are spot welded to the load deck (101).

[00042] Moreover, as per alternative embodiment, the number of long members (201) and cross members (202) can be varied based on application, requirement of load, safety consideration and architecture of the vehicle etc.

[00043] The load deck (101) is mounted to the chassis frame structure (as shown in figure 3) through a plurality of mount structures (204, 205). The mount structures (204, 205) are fixedly attached to the load deck (101). As per preferred embodiment the mount structures (204, 205) are spot welded to the mount structures (204, 205). The mount structures (204, 205) includes primary mount structures (205) and secondary mount structures (204). The primary mount structures (205) are spot welded to the long member (201). However, the secondary mount members (204) are welded to both cross member (202) and long member (201). Further, the load deck (101) is provided with a service window (203) for ease of doing service without dismounting the load deck (101).

[00044] Figure 3 illustrates a partial side view of the multitrack light commercial cargo vehicle and localized exploded perspective view of body structure of a multitrack light commercial cargo vehicle. The chassis frame structure (301) of the multitrack light commercial cargo vehicle is configured to have a plurality of brackets (302). The brackets (302) are fixedly attached to the chassis frame structure (301). Each one of said brackets (302) is configured to have hole (302h) for receiving an attachment means (305).

[00045] The mount structure (204, 205) is sandwiched between the chassis frame structure (301) and the load deck (101). Since the lower portion of the primary mount structure (205) and secondary mount structure (204) are identical in construction, reference would be made to only one of them for the purposes of brevity. As shown in the localized view the primary mount structure (205) is detachably attached to the chassis frame structure (301) through an attachment means (305) to secure the load deck (101) to the chassis frame structure (301). The attachment means (305) includes nut and bolt with washer (304). Further, a cushion member (303) is disposed between the primary mount structure (205) and the chassis frame structure (301). The cushion member (303) configured to have a hole (303h) to receive the attachment means (305). The cushion member (303) configured to have predetermined profile. The predetermined profile includes rectangular shape. The cushion member (303) isolates the vibration coming from the engine or wheels to the load deck (101) and the opposite reaction forces coming from the load deck (101) to the chassis frame structure (301).

[00046] Figure 4 illustrates a side view of a fabricated unfolded (commonly referred to as strip layout or blank layout) mount structure (401). The fabricated unfolded mount structure (401) is configured to have a predetermined shape. The predetermined shape of the fabricated unfolded mount structure (401) is configured to have a first portion (401b). The first portion (401b) configured to have an opening (401i), at least one second portion (401c), at least one third portion (401a) and at least one fourth portion (40 Id). Each one of said second portion (401c) is extending from opposite edges of said first portion (401b). Further, each one of said third portion (401a) and said fourth portion (40 Id) extends from at least one side edge of said first portion (401b). The fourth portion (401d) is configured to have a fifth portion (40 le). The fifth portion (40 le) is extending from opposite edges of said fourth portion (401d). Furthermore, the fifth portion (401e) has at least one sixth portion (40 If). The sixth portion (40 If) extending from at least one edge of one of said fifth portion (40 le). Moreover, the fourth portion (40 Id) is provided with at least one seventh portion (40 lg). The seventh portion (40 lg) is extending from at least one edge of said fourth portion (401d). The seventh portion (401g) configured to have an opening (40 lh) of predetermined shape. As per an embodiment, the predetermined shape includes rectangular configuration. [00047] Figure 5 illustrates a flow chart depicting method of fabrication and method of bending forming primary mount structure (205) and secondary mount structure (204). A blank of predetermined physical property E - modulus and yield strength is processed. The blank is loaded on a table of cutting machine which is subject to material removal process at first step (S101). The material removal process is carried out in a laser cutting machine. In an alternative embodiment, the cutting operation can be performed by using method applying shear force to separate the material. The excess material is removed by using heat of laser instead of shearing force. Thus, material removal process creates the openings and cutout in blank of predetermined thickness. Thus, a predetermined profile of fabricated unfolded mount structure is obtained at second step (SI 02). Further, the fabricated unfolded mount structure is unloaded from the cutting machine at third step (SI 03). The cutting operation is followed by the bending operation. The bending operation of unfolded fabricated mount structure constitutes basic straight-line bends. As per preferred embodiment, the bending along a straight line is performed in press brake machine at fourth step (SI 04). The press brake machine involves a punch which moves the blank down into vee- die under high loading. The method of bending comprises several bending steps at predetermined bend angles at fifth step (SI 05) on fabricated unfolded mount structure until its desired cross section geometry is obtained. As per preferred embodiment the unfolded mount structure is placed on the die as punch moves downwards to a make a straight-line bend such that pair of fifth portion (40 le) is bend towards fourth portion (40 Id) at a predetermined angle at sixth step (S105A). Further followed by, bending of fourth portion (40 Id) at a predetermined angle towards first portion (401b) at seventh step (S105B). Subsequent to that, the second portion (401c) is bend at a predetermined angle towards first portion (401b) at eighth step (S105C). subsequent to that, the sixth portion (40 If) is bend at a predetermined angle away from first portion (401b) at ninth step (S105D). The sixth portion (40 If) acts as an attachment flanges on the long member (201) (as shown in figure 2). Further, peripheral sidewall of fifth portion (40 le) is bend at predetermined angle away from first portion (401b) at tenth step (S105E). These peripheral side wall acts like side flanges. Further, the primary mount structure (205) is unloaded from the press brake machine at eleventh step (S106). However, in addition to above, an additional bending step is performed to get desired geometry of secondary mount structure (204). The seventh portion (40 lg) is bend away at a predetermined angle from the first portion (401b) at twelfth step (S105F) followed by unloading of secondary mount structure (204) from the press brake machine at thirteenth step (S107).

[00048] Figure 6 illustrates perspective view of the primary mount structure (205) and secondary mount structure (204). Since the lower portion of the primary mount structure (205) and secondary mount structure (204) are identical in construction, reference would be made to only one of them for the purposes of brevity. The primary mount structure (205) and secondary mount structure (204) are configured to have substantially U - shaped profile with a partially enclosed section. The primary mount structure (205) is configured to have a base portion (205a) and at least three side walls (205b) extending in vertical direction from the base portion (205a). The base portion (205a) is configured to have an opening (401i) to receive an attachment means (305) (as shown in figure 3). At least one of said side walls (205b) is configured to have at least one side flange (205c). The side flanges (205c) are extending from the peripheral edges of said side wall (205b). Further, each one of said sidewall (205b) is configured to have an end flange (205d).

[00049] The architecture of secondary mount structure (204) is configured to have at least three end flanges (204d) parallel to the base portion (204a). As per preferred embodiment at least one of said end flange (204d) is configured to have opening (40 lh). Further, the architecture of primary mount structure (205) comprises at least one end flange (205d) extending vertically such that it is substantially perpendicular to the base portion (205a).

[00050] Figure 7 illustrates a graphical representation showing the buckling analysis of the proposed mount structure and conventional mount structure. The X- axis represent the load applied on the mount structures and Y - represents the deflection or deformation in the mount structure. Further, the curve A denotes the proposed mount structure and curve B denotes the conventional mount structure. It is evident from the graph that the deformation value (Y axis) of conventional mount structure is more for given load (X axis) as compared to the proposed bracket under proper loading. Thus, load carrying capacity of proposed bracket is greater than conventional bracket.

[00051] According to above architecture, the primary efficacy of the present invention is that the vertical walls are configured to uniformly distribute the load when vehicle accelerates or decelerates as weight is transferred from front to back during acceleration and back to front during deceleration results in reaction forces coming from the wheels in the longitudinal direction of the vehicle. Further while taking turns the side flanges are configured to uniformly distribute the loads. Thus, lateral or longitudinal weight transferred from wheels to the load deck area is uniformly distributed by mount structure without buckling and without any additional reinforcement bracket. This ensures reduction in manufacturing cost and time.

[00052] According to above architecture, the second efficacy of the present invention is that, the mount structure economically meets different requirements on strength, reliability. The lateral or longitudinal weight transferred from wheels to the chassis further to the load deck area through the mount structure. The mount structures are configured to uniformly distribute the load during lateral or longitudinal weight transfer to the load deck area from the chassis frame structure. This is enabled since more loading area is available for the load distribution near load deck. In addition to that, mount structure is spot welded to the load deck which increases capacity to take shear stresses thus, improving the reliability of the mount structure.

[00053] According to above architecture, the third efficacy of the present invention is that, the mount structure is configured to have multiple extended portion which are oriented in predetermined way to increase its strength and stiffness to bear load without buckling.

[00054] According to above architecture, the fourth efficacy of the present invention, the side flanges carry high stress levels and contribute large area moment of inertia. [00055] According to above architecture, the fifth efficacy of present invention is that, the load or goods are held securely on the load deck due to rigid and reliable mount structure, thus, stability of the load deck on rough and unmetalled roads is ensured. [00056] According to above architecture, the sixth efficacy of the present invention is that the load deck is mounted at a predetermined higher height enabled by incorporating the mount structure as per the present invention and this predetermined height enables incoming natural air to pass through the engine assembly or electric motor. Thus, performance of engine assembly or electric motor is improved due to effective cooling.

[00057] According to above architecture, the seventh efficacy of the present invention is that two different types of mount structures are manufactured using single blank and without use of customized punch and die. Thus, it reduces the tooling cost and further improves the production rate of the vehicle. [00058] According to above architecture, the eight efficacy of the present invention, that mount structure is a partially enclosed section which is oriented in an outward direction of the vehicle. This ensures easy access to the attachment means while assembly or servicing of the vehicle. Hence, dismounting or mounting of load deck is single handed or single user operation is enabled. [00059] While the present invention has been shown and described with reference to the foregoing preferred embodiments, it will be apparent to those skilled in the art that changes in form, connection, and detail may be made therein without departing from the spirit and scope of the invention. List of references:

Longitudinal axis (YY’) 30 Frame assembly (F) Lateral axis (LL’) 101 Load deck

Upward direction (Up) 101a Flatbed Downward direction (Dw) 101b Side walls 101c Tail gate 300 Multi track light commercial vehicle

101L Lower surface of the load deck 301 Chassis frame structure

101LS Side edges of lower surface 302 Plurality of brackets of load deck.

25 302h Hole in the bracket

201 Long members

303 Cushion member

202 Cross members

303h Hole in the cushion 202F First cross member member 202S Second cross member 304 Washer 203 Service window 30 305 Attachment means

204 Secondary mount structure 401 Fabricated unfolded mount structure

204a Base portion

401a Third portion

204b Side walls

401b First portion

204c Side flange

35 401c Second portion 204d End flanges

401d Fourth portion

205 Primary mount structure

40 le Fifth portion

205a Base portion

40 If Sixth portion

205b Side walls

40 lg Seventh portion

205c Side flange

40 40 lh Opening in seventh portion 205d End flanges