Abstract:
A suspension system for a vehicle includes two laterally spaced front and rear wheel assemblies, each assembly including a wheel and a wheel mounting, permitting movement of the wheel in a generally vertical direction, bounce support devices supporting the vehicle body, and roll control devices controlling roll attitude. The roll control devices include respective second coupling devices interconnecting the longitudinally adjacent wheel assemblies, and further include transfer devices interconnecting the second coupling devices of each pair of longitudinally adjacent wheel assemblies.

Description:
This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/AU98/000478 which has an International filing date of Jun. 22, 1998, which designated the United States of America. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed to vehicle suspension system for use in automobiles, trucks and other vehicles. 
     2. Description of the Related Art 
     In the applicant&#39;s earlier Australian patent application No. 19420/95, there is shown a vehicle suspension system including two laterally spaced front wheel assemblies and two laterally spaced rear wheel assemblies. In each of the arrangements described in the above noted patent application, a first coupling means for interconnecting laterally spaced wheel assemblies is respectively provided at the front and the rear ends of the vehicle. Second coupling means for respectively interconnecting the longitudinally adjacent wheel assemblies are provided on each side of the vehicle. The first coupling means primarily support the weight of the vehicle body and provide four wheel bounce resilience whereas the second coupling means provides roll attitude control for the vehicle. In the arrangements described in this patent application, the first coupling means are generally provided by a pair of contra-rotational torsion bars respectively located at the front and rear of the vehicle. The second coupling means are also provided by a pair of contra-rotational torsion bars respectively provided on each side of the vehicle. A lateral roll control arrangement links the second coupling means. This suspension system provides for movement of one wheel in one direction resulting in the longitudinally adjacent and laterally adjacent wheels being respectively urged in the opposite direction. Furthermore movement of both wheels on one side of the vehicle in one direction during roll movement of the vehicle will urge movement of both the wheels on the other side of the vehicle in the same direction to thereby control vehicle roll; Details of the vehicle suspension system described in the above noted patent application are incorporated herein by reference. 
     It has been found in practice that it is difficult to accommodate a vehicle suspension system of the above noted type into existing vehicles because of the limited space provided under these vehicles and the configuration of the components of the vehicle as they have not been specifically designed to allow for such a vehicle suspension system. More particularly, these above noted types of suspension system may input suspension loads into the body structure at different points to conventional suspension systems. Due to the mechanical advantage (or motion ratio) of some elements of the suspension linkages to the wheel, these suspension loads may cause deflection and therefore noise if input directly into the lightweight structures of modern monocoque (or unitary) construction vehicle body shells. 
     Additionally, in the suspension system described in the aforementioned Australian application, only one form of low roll stiffness bounce support means is disclosed. It may be advantageous to use alternative arrangements of low roll stiffness bounce support, to facilitate packaging of the suspension system on a wider range of vehicles. Alternatively, it may be advantageous for the roll control arrangement be used in conjunction with conventional independent support arrangements for each wheel, which may provide a roll stiffness and therefore a warp (or cross-axle articulation) stiffness. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is therefore to provide a vehicle suspension system of the above noted type that can be accommodated under existing vehicles, preferably without inputting large loads into the body structure of the vehicle. 
     With this in mind, according to one aspect of the present invention provides a suspension system for a vehicle, the suspension system including: 
     two laterally spaced front wheel assemblies and two laterally spaced rear wheel assemblies, each wheel assembly including a wheel and a wheel mounting supporting the wheel to permit movement of the wheel in a generally vertical direction relative to a body of the vehicle; 
     bounce support means for supporting the vehicle body above the wheels and roll control means for controlling a roll attitude of the vehicle body with respect to the wheels; 
     said roll control means including respective second coupling means interconnecting each wheel assembly to the longitudinally adjacent wheel assembly, and further including transfer means interconnecting the second coupling means of each said pair of longitudinally adjacent wheel assemblies; 
     said second coupling means being adapted to urge in response to a movement of the wheel of one said wheel assembly in a substantially vertical direction a movement of the wheel of another said wheel assembly connected to said same second coupling means in an opposing direction relative thereto; 
     said second coupling means also including average movement generating means arranged to generate a movement therein substantially proportional to the average movement of the two wheels connected thereto on one side of the vehicle, said generated average including a factor for the roll moment distribution of the roll control means, the transfer means transferring said generated average movement of said second coupling means to the other said second coupling means on the opposite side of the vehicle; 
     wherein the loads generated in the average movement generation means and the transfer means are resolved in a localised structural area of the suspension system, and 
     wherein the bounce support means and roll control means respectively provide separate bounce and roll stiffness for the vehicle. 
     The suspension system can take advantage of spaces located under the vehicle to locate components which resolve the transverse suspension loads (generated in the roll control means) by suitable location of the structural area(s). 
     The second coupling means may be used on a vehicle provided with conventional independent supports (which provide additional roll stiffness). 
     However it may be preferable to provide bounce support means including respective first coupling means interconnecting each said wheel assembly to the laterally adjacent wheel assembly to provide a complete suspension system with substantially zero warp (or cross-axle articulation) stiffness. 
     Alternatively a compromise between conventional independent supports and the preferred interconnected supports may be chosen. The bounce support means for at least one pair of laterally spaced wheel assemblies may include at least a first coupling means interconnecting each said wheel assembly, said first coupling means supporting at least a portion of the load on the associated wheel assemblies whilst providing substantially no roll stiffness. 
     Where at least one first coupling means is provided, a height adjustment means may also be included to vary the average height of the body with respect to the associated wheels. 
     The substantially transverse suspension loads generated by the suspension arrangement may be resolved in at least one subframe upon which the vehicle body is supported. The front and rear wheel mountings may be respectively located on separate subframes, the roll control loads being resolved on at least one of the subframes. Alternatively, the roll control loads may be resolved on a further subframe. It is also envisaged that the transverse suspension loads be resolved in at least one reinforced structural area of the vehicle body. 
     The use of suspension subframes is advantageous for assembly of the vehicle on a production line. Parts or all of the suspension system may be produced as one or more sub-assemblies which are easily attached onto the vehicle body during whole vehicle assembly on a production line. One subframe could be provided with the suspension system attached to allow easy assembly and resolve all the loads. 
     Each second coupling means may include a roll lever arm for each said wheel assembly, the load in each roll lever arm varying in response to the warp and roll displacements of the wheels with respect to the body, and each second coupling means may include a linkage arrangement interconnecting the roll lever arms, the linkage arrangement of adjacent second coupling means being interconnected by the transfer means, the position of the connection of the transfer means to the linkage arrangements determining the roll moment distribution of the roll control means. 
     Each second coupling means may include at least one elongate torsion member connected to a said wheel mounting, the associated said roll lever arm extending from each torsion member. 
     The second coupling means may include a pair of elongate torsion members, one end of each torsion member being connected to and extending from a said wheel mounting, the other end of each torsion member including a roll lever arm extending from the torsion member, the roll lever arms being interconnected to by a linkage arrangement, the linkage arrangement of adjacent second coupling means being interconnected by the transfer means. 
     It is however also envisaged that the torsion members on both sides of the vehicle be aligned in an “X” configuration, with the transfer means located at a central location between the four wheel assemblies. In this configuration, the major rotational axes of the components of the first and second coupling means (ie the torsion members) are generally aligned towards a said structural area where loads from the first and second coupling means are resolved. 
     There are different methods which may be used to achieve the desired results from the transfer means. For example, the transfer means may include a Watts link. 
     Alternatively, if the roll lever arms of one said second coupling means are arranged to point substantially upwards and the roll lever arms of the other second coupling means on the opposite side of the vehicle point substantially downwards, then the transfer means interconnecting the linkage means may be a member which is substantially aligned with a transverse axis across the vehicle. This arrangement is a lever analogy of the gear arrangement shown in FIG. 3 of the Applicant&#39;s above-mentioned Australian patent application No. 19420/95, which could also be used. 
     The linkage arrangement may include a flexible connection means at each end thereof for providing the respective connection to each roll lever arm. 
     According to a first possible arrangement, the first coupling means of at least one pair of laterally adjacent wheel assemblies may include a bounce lever arm for each wheel assembly, the load in each bounce lever arm varying in response to the bounce displacements and loads on the associated wheel assemblies. The first coupling means may further include a connection means interconnecting the bounce lever arm of one wheel assembly with the bounce lever arm of the laterally adjacent wheel assembly. 
     At least one of the first coupling means may include at least one torsion bar interconnected between at least one wheel mounting and the associated bounce lever arm. 
     The torsion members of at least one second coupling means may be hollow, a said torsion bar of the first coupling means being located within each said torsion member, with one end of the torsion bar being fixedly connected to the torsion member. 
     The bounce lever arm may extend from the end of the torsion bar opposite to the fixed end thereof. Alternatively, an aperture may be provided through the wall of the torsion member to provide clearance for the bounce lever arm to extend from the torsion bar. This provides a relatively compact arrangement which can more readily be positioned into a vehicle. 
     At least one of the torsion members of the second coupling means may include a bar extension from the torsion member, the bar extension forming part of the first coupling means. The bar extension may be integral with or fixedly secured to the torsion member. The bar extension may include a bounce lever arm extending therefrom. The first coupling means may also include a resilient means coupled at each end thereof to the bounce lever arms of laterally spaced bar extensions of the torsion members. 
     The connection means of the bounce supports may be a relatively rigid member interconnecting the bounce lever arms of laterally adjacent torsion bars. 
     Alternatively, the connection means interconnecting the bounce lever arms of laterally adjacent torsion bars may include a resilient means. 
     The resilient means may include a spring member and/or an hydraulic ram in fluid communication with an accumulator. 
     According to a second aspect of the invention, the first coupling means of at least one pair of said laterally adjacent wheel assemblies may include a pair of fluid rams, the fluid rams being respectively connected to the wheel mounts of laterally adjacent wheel assemblies, the hydraulic rams being connected by a fluid conduit to provide fluid communication therebetween, and an accumulator located on the fluid conduit. 
     According to yet another aspect of the present invention, there is provided an elongate suspension member for a vehicle suspension system including a tubular member, and a torsion bar accommodated within the tubular member, one end of the tubular member being fixedly secured to a wheel assembly, the other end being connected to one end of the torsion bar. A lever arm may extend from the other end of the torsion bar, the lever arm being connected to the lever arm associated with the laterally adjacent wheel assembly. 
     According to yet another alternative, one end of the vehicle may include different types of the first coupling means described above at different ends of the vehicle. 
     According to another aspect of the invention, there is provided a vehicle incorporating a suspension system including any aspects of the above described invention. 
     It will be convenient to further describe the invention by reference to the accompanying drawings which illustrate preferred embodiments of the invention. Other embodiments of the invention are possible, and consequently the particularity of the accompanying drawings is not to be understood as superseding the generality of the proceeding description of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a perspective view of a first preferred embodiment of a vehicle suspension system according to the present invention; 
     FIG. 2 is a detailed cross-sectional view of a part of the vehicle suspension system of FIG. 1 showing a torsion member accommodating a torsion bar; 
     FIG. 3 is a perspective view of a second preferred embodiment of a vehicle suspension system according to the present invention; 
     FIG. 4 is a perspective view of a third preferred embodiment of a vehicle suspension system according to the present invention; 
     FIG. 5 is a perspective view of a fourth preferred embodiment of a vehicle suspension system according to the present invention; 
     FIG. 6 is a perspective view of a fifth preferred embodiment of a suspension system according to the present invention; and 
     FIG. 7 is a side cross-sectional view of the suspension system of FIG. 6 mounted on a vehicle; 
     FIG. 8 is a perspective view of a sixth preferred embodiment of a vehicle suspension system according to the present invention; and 
     FIG. 9 is a perspective view of an alternative support means for use on a suspension system according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring initially to FIG. 1, there is shown a vehicle suspension system including a front, middle and rear subframe  1   a ,  1   b ,  1   c . A pair of laterally adjacent front A-frames  2 ,  3  are pivotally mounted on the front subframe  1   a  and a pair of laterally adjacent rear A-frames  4 ,  5  are pivotally mounted on the rear subframe  1   c  on brackets  9  extending from the respective subframes  1   a ,  1   c . The A-frames  2 ,  3 ,  4 ,  5 , also known as “wishbones” carry the wheels (not shown) which support the vehicle. The wheels are able to move in a generally vertical direction relative to the subframes. 
     A first coupling means  50  interconnects the two laterally adjacent front wishbones  2 ,  3 . A further first coupling means  50  interconnects the laterally adjacent rear wishbones  4 ,  5 . Furthermore, the wishbones  2 ,  4  on the left side of the vehicle are interconnected by means of a second coupling means  60 . The wishbones  3 ,  5  on the right hand side of the vehicle are similarly interconnected by a second coupling means  60 . 
     The second coupling means  60  includes a pair of torsion members  7 , or “roll tubes”, located on each side of the subframes. Each roll tube  7  is fixed to or integral with an adjacent wishbone. A roll lever arm  11  extends from each roll tube  7 . A linkage member  12  interconnects adjacent roll tubes  7 . The linkage member  12  is coupled via a flexible junction  13  to the roll lever arm  11  of each roll tube  7 . The linkage members  12  are interconnected by a transfer means  10 , shown here in the form of a “Watts” linkage including a central Watts link  15  pivotally mounted on the middle subframe  1   b . Extension arms  16  extend from each end of the Watts link  15  to connect the Watts link  15  to each link member  12 . Each extension arm  16  are hingedly connected at opposing ends thereof to the Watts link  15  and to pivot point  12   a  on the link member  12  respectively. The above arrangement of the roll tubes  7  and the Watts linkage  10  provide roll attitude control for the vehicle suspension system. 
     The central roll load transfer means  10 , may be accomplished using other arrangements, such as a linkage version of the gear arrangement shown in FIG. 3 of the Applicant&#39;s aforementioned Australian patent application No. 19420/95. For example, the roll lever arms  11  may extend from the roll tubes  7  in a generally upwards direction on one side of the vehicle, and in a generally downwards direction on the opposite side on the vehicle. The linkage means  12  interconnecting the roll lever arms of adjacent roll tubes may then be interconnected by a simplified transfer means in the form of a beam member. In this arrangement it may be preferable to run the roll tubes on one side of the vehicle upwards towards the transfer means (with respect to the lines of the roll tubes on the other side of the vehicle) such that the roll lever arms of both second coupling means and the transfer means may be packaged into a volume of reduced overall height. 
     The first coupling means  50  includes a torsion bar  8  accommodated within each roll tube  7  as best shown in FIG.  2 . The torsion bar  8  has a fixed end  20  fixedly secured to the roll tube  7 . The torsion bar  8  also has a free end  21  extending from the roll tube  7 . A bounce lever arm  22  extends from the torsion bar free end  21 . A locating bearing  23  locates the torsion bar  8  within the roll tube  7 . 
     The torsion bar free end  21  is pivotally supported within a bracket  17  extending from the vehicle frame  1 . 
     Each laterally adjacent pair of torsion bars  8  are interconnected by means of a transverse bounce bar  24 . The bounce bar  24  is connected at each end of by means of a flexible connection  25  to the bounce lever arm  22  of each torsion bar  8 . 
     Because the torsion bars  8  are fixedly connected to the roll tubes  7  which in turn is fixedly connected to the wishbones  2 ,  3 ,  4 ,  5 , the interconnected torsion bars  8  act to support the weight of the vehicle and provide four wheel bounce resilience. However, as the torsion bars  8  are not mechanically resolved directly to the vehicle frame  1  and are only joined transversely to one another, they do not afford any roll attitude support themselves. It should also be noted that although the roll tubes  7  are hollow, they are still torsionally relatively rigid. There is only sufficient torsional flexibility to allow for any roll bounce requirements. 
     FIG. 3 shows an alternative possible arrangement according to the present invention and integers corresponding to integers in FIG. 1 are provided with the same reference numeral for clarity purposes. The vehicle frame  1  of FIG. 1 is replaced by a front vehicle sub frame  30  and a rear vehicle sub frame  31 . The front vehicle sub frame  30  supports the front wishbones  2 ,  3  while the rear vehicle sub frame  31  supports the rear wishbones  4 ,  5 . The wishbones are supported for pivotal movement on brackets  90  extending from the front and rear sub frames  30 ,  31  respectively. 
     This arrangement also provides a first coupling means  50 ,  51  and a second coupling means  60  according to the present invention. The second coupling means  60  includes a long torsion member  32  and a short torsion member  33  respectively located on each side of the vehicle. These torsion members  32 ,  33  are solid and not hollow as shown in FIG.  1 . The torsion members  32 ,  33  are however also interconnected by a Watts linkage  10  in a similar manner as in FIG. 1.. The difference is that the Watts linkage  10  has been moved away from the centre of the vehicle as shown in FIG. 1 towards the rear of the vehicle as shown in FIG.  3 . This arrangement is preferable because there is generally a greater amount of floor height and space towards the rear of the vehicle. This is clearly shown in FIG.  7 . The location of many of the components of the suspension system towards the rear of the vehicle facilitates packaging of the vehicle suspension system within the vehicle. Also, as the Watts linkage  10  transmits roll forces between the torsion members  32 ,  33  on either side of the vehicle, this resolves all the high roll forces within the rear sub frame  31 . 
     FIG. 3 shows the torsion members  32 ,  33  being integral or fixedly secured to the respective wishbones  2 ,  3 ,  4 ,  5 . It is however to be appreciated that the torsion members  32 ,  33  may alternatively be connected to the wishbones by way of drop links. The first coupling means  50 ,  51  is provided at the front end of the vehicle by a front bar extension  34  which is integral with or fixedly secured to the long torsion member  32  and front wishbone  2 ,  3 . A bounce lever arm  35  extends from the front bar extension  34 . A resilient means  36  interconnects the bounce lever arms  35  of the laterally adjacent front bar extensions  34 . The resilient means  36  includes a hydraulic ram  37  and associated accumulator  38 . The ends of the hydraulic ram  37  are respectively coupled to the bounce lever arms  35  by a piston rod  39  extending from one end of the hydraulic ram  37  and a connection arm  39   a  extending from the other end of the hydraulic ram  37 , the peripheral end of the piston rod  39  and the connection arm  39 a being coupled to the respective bounce lever arm  35  by means of a resilient connector  40 . 
     The first coupling means of the rear vehicle sub frame  31  is similar to that of the front vehicle sub frame  30  in that each short torsion member  33  of the second coupling means is respectively integral with or fixedly coupled to a rear bar extension  41  for the first coupling means  51 . The rear bar extension  41  is integral with or fixedly coupled to a respective rear wishbone  4 ,  5 . Each bar extension  41  includes a bounce lever arm  42  with a resilient means  43  interconnecting the bounce lever arms  42  of the laterally adjacent rear bar extensions  41 . The first coupling means  51  of the rear vehicle sub frame  31  differs from the first coupling means  50  of the front vehicle sub frame  30  in that the resilient means  43  is provided by a coil spring in place of a hydraulic ram  37 . The first coupling means  51  of the rear vehicle sub frame  31  otherwise operates in the same manner. 
     The vehicle suspension system shown in FIG. 4 is generally the same as the system shown in FIG. 3 except that the first coupling means  50  of the front vehicle sub frame  30  is provided by a pair of hydraulic rams  70 , each hydraulic ram  70  being provided between a front wishbone  2 ,  3  and the vehicle chassis (not shown). The hydraulic rams  70  are joined by a transverse conduit  71  to allow fluid communication between the rams  70 . An accumulator  72  is provided in the transverse conduit  71 . The long torsion members  32  of the second coupling means  60  are integral with or fixedly secured to the respective front wishbones  2 ,  3 . There is however no bar extension  34  as shown in FIG.  3 . The arrangement of the first coupling means  51  on the rear vehicle sub frame  31  is however identical to that shown in FIG.  3 . 
     In FIG. 5, the second coupling means is provided with a roll tube  80  fixedly coupled to a front wishbone  2 ,  3  and a rear torsion member  81  fixedly coupled to a respective rear wishbone  4 ,  5 . The first coupling means  50  of the front vehicle sub frame  30  includes a torsion bar  82  located within tubular member  80  in the same manner as shown in FIG. 2. A bounce lever arm  83  extends from the end of the roll bar  82  extending from the end of the roll tube  80 . The lever arms  83  of the laterally adjacent torsion bars  82  are interconnected by means of a rigid link member  84 . The resilience of the first coupling means  50  is provided by the torsion bars  82  which normally or beneficially extend greater than one half the length of the vehicle to provide sufficient resilience whilst not diminishing the longevity of the torsion bars  82 . 
     The first coupling means  51  of the rear vehicle sub frame  31  has a similar arrangement to that shown in FIGS. 3 and 4 except that only a short rear bar extension  85  extends from the torsion member  81 . A bounce lever arm  86  extends from each rear bar extension  85 , with the bounce lever arms  86  being interconnected by a resilient means  51  in the same manner as shown in FIGS. 3 and 4. Additionally, the subframe  31  incorporates extra members  31   a  which extend laterally across the vehicle and include mounting points for the torsion members  80  and  81 . These extra members resolve the lateral forces generated in the torsion members and their interconnecting linkage arrangement, and include mounts at their ends to help input roll forces into the body structure. This is an example of how a roll load subframe may be incorporated into one of the front or rear suspension mounting subframes to resolve suspension loads within localised structures, thereby limiting the loads input into the body shell. Although these extra members  31   a  are only shown in FIG. 5, they may also be used in any of the arrangements shown in FIGS. 3 to  7 . 
     The vehicle suspension system shown in FIG. 6 is generally the same as the suspension system shown in FIG.  5 . The various components on the rear vehicle sub frame  31  is identical in both arrangements. The primary difference is in the layout of the components on the front vehicle sub frame  30 . In particular, the roll tubes  100  fixedly coupled to the front wishbones  2 ,  3  include an aperture  103  passing through the side of each roll tube  100 . A torsion bar (not shown) is accommodated within each roll tube  100 . A bounce lever arm  101  extends from each torsion bar through the aperture  103 . The bounce lever arms  101  are then joined by a rigid link member  102  to thereby provide the first coupling means  50  for this arrangement. The first coupling means  50  of this arrangement operates in the same manner as the first coupling means shown in FIG.  5 . 
     This vehicle suspension system arrangement can therefore move all of the components that take up vertical space towards the rear of the vehicle. This arrangement facilitates packaging of the vehicle suspension in a vehicle. Referring to FIG. 7, the suspension system of FIG. 6 is shown mounted on a vehicle  200 . The typical shape of the vehicle floor  201  is such that clearance for the various components of the vehicle suspension system can be provided to the rear of the vehicle in a standard cavity  202  under the floor  201  of the vehicle. 
     Alternatively, it may be useful to arrange the components of the vehicle suspension system in an “X” configuration for packaging and other reasons as shown in FIG.  8 . This arrangement has similarities with the arrangement shown for the front vehicle subframe  30 ,in FIG. 6 in that the vehicle front subframe  30  supports the front wishbones  2 ,  3  which are each connected to a roll tube  200 , each roll tube  200  accommodating a torsion bar (not shown) therein. A bounce lever arm  202  extends from each torsion bar through an aperture  201  provided through the wall of the roll tube  200 , and the laterally adjacent bounce lever arms  202  are joined by a rigid link member  202  in a similar manner to FIG.  6 . 
     The primary differences are that the roll tubes  200  are connected by drop links  204  to their associated wishbone  2 ,  3  and that the roll tubes  200  are angled inwardly from the wishbones  2 ,  3  towards a generally central location of the vehicle. This location may for example be the hump provided under and between the front seats of a vehicle and above the drive shaft of the vehicle. The rear vehicle subframe  31  is also provided with a similar suspension arrangement to the arrangement provided for the front vehicle subframe  30 . Therefore, roll tubes  200  are also connected by drop links  204  to the rear wishbones  4 ,  5 , with the roll tubes  200  being angled inwardly to the said central location. The roll tubes  200  are therefore configured in an “X” configuration. 
     The roll tubes  200  are interconnected by link members  230  which are in turn connected by a Watts linkage  250  at the central location in a similar manner as in the earlier described arrangements. Furthermore, the bounce lever arms  202  and the rigid link members  203  are all located at the central location. This provides a compact arrangement for the various connection components of the suspension system within one location. Furthermore, this arrangement has mechanical advantages in that the load applied to the connection components are relatively lower than for other arrangements. Also most of the roll forces are resolved within this central location. 
     It is noted that the “Roll Split” or roll moment distribution for the suspension system can be altered by changing the attachment point of the transfer means with the link members in any of the above described arrangements. Also the transfer means can include resilient members to provide roll resilience. 
     In all of the above arrangements, the components of the suspension system are conveniently located away from the front and rear ends of the vehicle as required. This ensures that the suspension system does not interfere with the crumple zones of the vehicle. Furthermore, the various possible arrangements of the vehicle suspension system facilitate packaging of the system in conventional vehicles. This therefore facilitates the minimum number of design changes which need to be made to existing vehicle platforms. 
     Referring now to FIG. 9, an alternative mechanical bounce support arrangement is illustrated applied to the rear pair of transversely adjacent of wheels with the vehicle chassis and the roll attitude control components omitted for clarity. The back right wishbone  5  has a first bounce lever arm  155  rigidly attached close to the axis of the rotation of the wishbone, a bounce tube  174  is rigidly attached close to the axis of rotation of the wishbone. A bounce tube  174  is rigidly attached to the back left wishbone  4  with the bounce torsion bar  173  attached to the tube at one end  175  by any known means such as a spline and extending back up inside the tube. The other end of the bounce torsion bar  173  back at the wheel end is connected to the second bounce lever arm  156 . The first and second bounce lever arms are interconnected as before by the support connecting link  157 . 
     Thus the torsion bar is loaded by the left wheel at its forward end  175  and loaded in the opposite direction by the right wheel at its rearward end providing resilient bounce support of the vehicle body. As the vehicle wheels move with respect to the body in roll or cross-axle articulation motions, the bounce lever arms, tube and torsion bar rotate, the support connecting link moves in a substantially lateral direction thereby substantially maintaining the same torque in the bounce torsion bar and consistent loading on the vehicle wheels. 
     Alternative height control means are also shown in FIG. 9 in the form of self-levelling dampers  176  are shown to help maintain vehicle ride height under differing load conditions. 
     The torsion bar arrangement has particular application on the rear suspension of vehicles as it may be possible to package the bounce torsion bar on one side of the vehicle only, the remainder of the space often being occupied by fuel tanks and exhaust system components. It is not necessary to rigidly fix the first bounce lever arm and the bounce tube to the respective wishbones, they being driven by intermediate linkages if desired. 
     The above “torsion bar within a tube” design may be used on both sides of the vehicle, with optionally, different length torsion bars from side to side if required. 
     In all of the above embodiments, it is possible to dampen roll motion if required by locating an external damper such as a conventional linear hydraulic cylinder damper between the vehicle body and each wheel mount.