Cross-Reference to Related Applications

This Patent Appl ication claims priority from Italian Patent Application No . 102022000013108 filed on June 21 , 2022 , the entire disclosure of which is incorporated herein by reference .

Technical Field

The present invention relates to a vehicle provided with a moving system for varying the distance in the vertical direction between the rear wheels and the bodywork when the vehicle is stationary .

In particular, the following description refers to a vehicle provided with a rigid axle rear suspension, without thereby losing its generality .

Background

As known, this type of rear suspension comprises a cross member usually de fined by a pipe , the lateral ends of which, also called "hub holders" , support respective hubs for the wheels and are coupled to the motor vehicle bodywork by means of respective springs and respective shock absorbers . Generally, the springs are leaf springs , and generally the ends of the cross member do not need arms or other mechanical elements to be connected to the bodywork . Some solutions of this type , however, involve the use of a Panhard bar to limit the lateral deviations of the transverse itsel f and/or the use of a stabili zer bar to reduce the roll of the vehicle during operation .

In the known solutions of the type j ust described, some types of rigid axles have the wheels coaxial with the cross member . In this way, the transmission hal f shafts can be housed in the cross member itsel f , to drive the two rear wheels , in case the latter are driven .

In the case where the two rear wheels are not driven (with the passage of the transmission line ) , there is theoretically greater freedom in the design of the suspension . In this context , there is a need to enhance the known solutions in order to provide a moving system that can vary the relative position between the wheels and the bodywork of the motor vehicle , when the latter is stationary, stopped or parked, in order to be able to approach and/or move the rear of the motor vehicle away from the ground . A function of this type can be useful , in particular, for adj usting the height position of a rear loading floor of the vehicle , depending on the speci fic needs that occur during normal loading and unloading operations , for example in the case of commercial vehicles with one or more rear doors .

In particular, a lowering of the rear loading floor facilitates loading and unloading operations with respect to users operating on the ground; and/or a lifting thereof can facilitate loading and unloading operations with respect to users operating on a raised platform, for example by aligning the rear loading floor with said platform .

In any case , adj usting the height of the rear loading floor to a stationary vehicle can have other advantages or other uses : for example , a lowering of the rear loading floor could be used to facilitate an electrical connection with respect to a charging station provided on the ground to recharge a battery pack on board the vehicle .

In known solutions , these requirements are met by active-controlled suspensions . This type of suspension, however, is relatively complex : in fact , it is preferable to adopt a traditional suspension, which is not an active type , to limit costs , simplify the layout of the systems , avoiding underbody air/oil circuits , and not to vary excessively the design and standard production lines . In the field of non-active type suspensions, solutions are known where the axes of the rear wheels are oscillating with respect to the suspension, in a free manner, which is without a motorized drive. Purely by way of example, consider documents EP1375202 and EP3912835A1.

These solutions, however, achieve a completely different purpose from that of the present invention, i.e., they compensate in the longitudinal direction (i.e., along the direction of travel of the motor vehicle) the road roughness, bumps and steps possibly encountered by the wheels during driving and/or during parking manoeuvres (in order to improve the feeling of comfort) . Thus, these known solutions do not provide suggestions for the present invention.

Summary

The object of the present invention is to provide a vehicle provided with a moving system for varying the relative position between the rear wheels and the stationary vehicle bodywork, which allows to satisfy in a simple and economical way the above requirements.

According to the present invention there is provided a vehicle, as defined in claim 1. Preferred embodiments are then the subject of the attached dependent claims.

Brief Description of the Drawings

The invention will now be described with reference to the appended drawings, which illustrate a non-limiting embodiment thereof, in which:

• Fig. 1 is a perspective view partially showing a preferred embodiment of the vehicle provided with a moving system for varying the distance in the vertical direction between rear wheels and bodywork, when the vehicle is stationary, according to the subject matter of the present invention;

• Fig. 2 illustrates, on an enlarged scale, the moving system seen in Fig . 1 for one of the two rear wheels ;

• Fig . 3 is similar to Fig . 2 and illustrates the moving system in a di f ferent conf iguration/position; and

• Fig . 4 is an enlarged top perspective with exploded parts of the moving system visible in Fig . 2 and 3 ; and

• Fig . 5 shows , on a further enlarged scale , a detail of the moving system with parts removed for clarity .

Description of Embodiments

In Fig . 1 , the reference numeral 1 indicates , as a whole , a vehicle 1 , partially illustrated, comprising a rear suspension la, in particular a suspension of the interlocking-wheel type . More particularly, the suspension la is of the rigid axle type .

The suspension la comprises a cross member 2 (partially illustrated) , which extends along a transverse axis 3 , which is orthogonal to a longitudinal direction of advancement 3a . The cross member 2 is designed and constructed so as to be rigid in bending and twisting and has two lateral ends 4 ( only one of which is illustrated) , opposite and coaxial with each other along the axis 3 : said ends 4 are coupled to a bodywork of the vehicle 1 , in particular they are coupled to respective longitudinal members or spars 4a of said bodywork, only one of which is illustrated .

On each side , this coupling is obtained by means of a relative spring 5 and a relative shock absorber 6 , of a known type and not described in detail : this section refers only to one side of the vehicle 1 , it being understood that the opposite side is symmetrical with respect to a vertical centreline plane , on which the direction 3a lies .

In the speci fic case illustrated, the spring 5 consists of one or more leaf springs and comprises an intermediate portion that is superimposed on the end 4 of the cross member 2 and is fixed to the latter by means of so-called struts . This intermediate portion of the spring 5 and the end 4 of the cross member 2 together define a support portion 5a forming part of the suspension la, for supporting a wheel hub 7 . In particular, the end 4 of the cross member 2 is connected to the hub 7 via a connection member 8 . At the same time , the hub 7 supports a corresponding rear wheel 9 ( illustrated in dotted line ) , rotatably about a rotation axis 10 , which preferably is parallel to and spaced apart from the axis 3 .

The member 8 and the hub 7 are connected to each other in a known manner and not described in detail , for example by threaded couplings which fix two flanges of these components ; at the same time , a portion of the member 8 is fixed to the support portion 5a in a known manner and not described in detail .

The shock absorber 6 has a lower end which is hinged to the member 8 and an upper end hinged to the spar 4a, in a known manner and not described in detail . Preferably, the suspension la further comprises a stabili zer bar 13 , the ends of which are coupled via respective connecting rods (visible in Fig . 4 ) to the members 8 . According to variations not illustrated, the coupling mode of the stabili zer bar 13 and/or of the shock absorbers 6 and/or of the springs 5 and/or of the hubs 7 and/or of the cross member 2 could be di f ferent from what is illustrated .

In the particular solution illustrated, for each side of the motor vehicle , the suspension la further comprises a limit switch damping element , which is indicated by the reference numeral 15 , is generally referred to as a "buf fer" , is disposed on a lower face of the spar 4a, is fixed to the latter in a known manner and not described in detail and protrudes downward along a vertical axis that is aligned with the support portion 5a .

According to one aspect of the present invention, the vehicle 1 comprises a moving system 20 for varying the vertical distance between the rotation axes 10 of the wheels 9 and the bodywork, i . e . , the vertical distance between the rotation axes 10 and the spars 4 a in the illustrated case , for example in order to adj ust the height with respect to the ground of a rear load plane (not illustrated) of the vehicle 1 .

With reference to Fig . 2 , according to one aspect of the present invention, the system 20 is operable with the vehicle stationary independently of the suspension la, i . e . , it does not use the springs 5 and/or the shock absorbers 6 as actuators for adj ustment , but includes at least one additional dedicated actuator 21 for performing this adj ustment . Preferably, the system 20 comprises two actuators 21 , each associated to a relative side of the vehicle 1 , i . e . , each for adj usting the height from the ground of a corresponding side of said rear load table .

The system 20 comprises at least one control element 21a ( schematically illustrated) that is manually operated and is available for the driver, for example in the cockpit control panel (not illustrated) of the vehicle 1 , to control the actuators 21 .

Appropriate inhibition systems 21b ( of software type and/or of mechanical type ) are provided on the vehicle 1 and operate automatically so that the system 20 is active and/or can operate and/or can be controlled only when the vehicle 1 is stationary, in particular in a stationary or parking condition .

In particular, once the system 20 is activated, the actuators 21 change the wheel-bodywork distance , from a starting value (which is variable depending on the speci fic situation, i . e . , depending on road conditions , slope, presence of steps , etc..., and depending on the weight on the rear loading plane of the vehicle 1 ) to a final value which can be fixed and predetermined, or variable depending on the driver ' s settings . This final distance value may reach a limit value which depends essentially on the construction characteristics of the suspension la and/or on the construction characteristics of the system 20 .

In the speci fic case under consideration, when the system 20 is activated, the actuators 21 lower the aforementioned rear loading floor, with the vehicle stationary, in order to be able to reach a minimum value of the wheel-bodywork distance .

In particular, the actuators 21 are supported in fixed positions by the cross member 2 .

According to the present invention, the system 20 comprises , for each side of the vehicle 1 , i . e . , for each wheel 9 , a relative transmission 22 , in particular of the screw and nut-screw type , which is integrated in the member 8 and is actuated by the actuator 21 to adj ust the relative position of the wheel 9 with respect to the support portion 5a and therefore the height position of the rear loading plane on that side , with respect to the ground .

Preferably, the transmission 22 on each side of the vehicle 1 is operated independently from the other side of the vehicle 1 . In this manner, the independent operation of the two actuators 21 can perform a levelling function of the rear load plane between the left side and the right side .

In particular, the two actuators 21 are housed inside the cross member 2 . According to variants not illustrated, the two actuators 21 may be arranged outside the cross member 2 ; in general , they are fixed to the support portions 5a of the rear suspension, even when the type of the latter does not provide for any cross member . On each side of the vehicle 1, the corresponding transmission 22 comprises a screw 24 and a nut-screw 25 (Fig. 4) , which is translatable along an axis 26 of the screw 24 in response to rotations of the latter, in turn caused by the actuation of the actuator 21. The axis 26 is vertical, or in any case is oriented so as to provide the nut-screw 25 with a vertical movement component, during translation.

In the specific example, the screw 24 is housed in a half-shell 27 that forms part of the member 8 and is connected to the half-shell 27 so as to be axially fixed and angularly rotatable about the axis 26.

At the same time, with reference to Fig. 4, the nutscrew 25 is fixed to an attachment element which is part of the member 8 and, in turn, is fixed to the hub 7. In the specific example illustrated, said attachment element is defined by a flange 28 which is preferably vertical and parallel to the direction 3a.

As can be deduced from the comparison of Figures 2 and 3, the nut-screw 25 and the flange 28 translate between two end-of-stroke positions, i.e., an upper position and a lower position .

In particular, during normal driving conditions of the vehicle 1, the system 20 is deactivated and the nut-screw 25 with the flange 28 is in the lower position (Fig. 3) with respect to the half-shell 27.

When the vehicle 1 is stationary, the system 20 may be activated. Here, the actuator 21 drives the screw 24 of the transmission 22. The nut-screw 25 therefore translates to the upper position, i.e., towards the bodywork (Fig. 2) .

This translation causes an approach of the bodywork towards the rotation axes 10 of the wheels 9 (and towards the cross member 2) , without causing any deformation of the spring 5 and/or the buffer 15 and any shortening of the shock absorber 6. In the upper position of the nut-screw 25 with respect to the hal f-shel l 27 of the member 8 ( Fig . 2 ) , the wheelbodywork distance reaches a minimum value .

Due to this vertical wheel and bodywork approach, caused by the system 20 , the ground clearance of the rear loading floor of the vehicle 1 can be adj usted and reduced to a limit value . This possibility of lowering allows the rear loading floor to be positioned at a desired height , up to this limit value , to facilitate loading and unloading operations or for other purposes , without necessarily having to adopt an active rear suspension .

Alternatively, the upper position of the nut-screw 25 ( Fig . 2 ) could correspond to the configuration of the system 20 in the normal driving conditions of the vehicle 1 , and the lower position could be adopted with the vehicle stationary to li ft the rear loading floor i f the need arises ( for example to facilitate loading/unloading with respect to a raised platform) . Or the transmission 22 could have an intermediate reference position for the nut-screw 25 , corresponding to the configuration in normal running conditions , with it being possible to li ft and lower the same nut-screw 25 ( and therefore the rear load table ) in opposite vertical directions , with the vehicle stationary .

With particular reference to Fig . 5 , the proposed solution has relatively small dimensions and is relatively simple to install . In particular, the screw 24 is driven in rotation by a helical sprocket , not shown, which rotates about an axis 30 orthogonal and spaced with respect to the axis 26 and meshes with the screw 24 to define a worm drive and helical wheel . In particular, said sprocket is protected or covered by a relative housing 31 , distinct from the hal fshell 27 and fixed with respect to the latter .

Preferably, the axis 30 is parallel to and spaced from the axis 3 . Preferably, the actuator 21 is defined by an electric rotary motor, and the axis 30 coincides with the axis of rotation of said electric motor .

Again, with reference to Fig . 5 , preferably, the lower end of the shock absorber 6 is hinged to an attachment flap that protrudes longitudinally outwardly from the hal f-shell 27 .

Referring to Fig . 4 , preferably, the hal f-shell 27 has at least one guide , which is parallel to the axis 2 for axially driving the f lange 28 and/or the nut-screw 25 . For example , such a guide is defined by two straight grooves 35 arranged on opposite parts of the screw 24 . In cross-section, the shape of the grooves 35 may be of various type , for example circular ( as in the illustrated example ) , prismatic, dovetail . The grooves 35 are slidably engaged by respective proj ections 36 of the flange 28 , in particular having a shape complementary to that of the grooves 35 , in cross section, to drive the translation along the axis 26 and prevent rotations of the same flange 28 about the axis 10 .

According to a variant not illustrated, the transmission 22 is of the reel and rack type , where the rack performs the function of a sliding element ( along the axis 26 ) for varying the position of the rotation axis 10 , in place of the nut-screw 25 ; and the toothed reel performs the function of a rotating element , driven directly or indirectly by the actuator 21 , in place of the screw 24 .

From the above , it is clear that the system 20 gives the vehicle 1 an additional possibility of adj ustment compared to those known solutions that are not equipped with active suspensions , to be used exclusively when the vehicle 1 is static, in particular with the engine of f . At the same time , the function of the suspension la is not compromised, as the transmissions 22 do not intervene in normal wheelbodywork oscillations during running . The proposed solution also appears relatively compact , while presenting suf ficient resistance characteristics and suf ficient li f ting/ lowering force to move the wheels 9 away/closer to the bodywork .

It is then evident that the solution with two separate actuators 21 allows to independently adj ust the two sides of the vehicle 1 and therefore also allows to position hori zontally the aforementioned rear loading floor, for example when the weight on said rear loading floor is not evenly distributed between the two sides or when one of the two rear wheels 9 is on a step . For example , an automatic adj ustment system could possibly be provided that maintains the loading floor, or a rear edge thereof , hori zontal during user loading and unloading operations ( sel f-levelling function of the rear loading floor ) , by actuating the actuators 21 independently of each other as a function of signals emitted by sensors that are configured so as to detect quantities indicative of the orientation and/or absolute angle around the direction 3a of the loading floor .

Further, as alluded to above , the system 20 does not intervene on the configuration of the suspension la, since the transmissions 22 are interposed between the support portions 5a and the hubs 7 .

Finally, from the foregoing, it is clear that modi fications and variants can be made to the vehicle 1 described with reference to the attached figures which do not fall outside the scope of protection of the present invention, as defined in the appended claims .

In particular, the type of rear suspension installed on the vehicle 1 could be di f ferent from the suspension la shown in the preferred embodiment ; for example , a twisting-bridge rear suspension, or of the independent-wheel type , could be provided; in these cases , the support portions 5a and their mode of coupling to the system 20 would be di f ferent from that shown by way of example for the suspension la .

Further, the rear suspension la could support a larger number of wheels , for example twin wheels .

Finally, the command to activate the actuators 21 of the system 20 could be arranged remotely, for example it could be provided via an application on a portable electronic device ( tablet , telephone , etc... ) , possibly without any control element on the instrument panel of the vehicle 1 .