Improvements in and relating to anti-roll bar assemblies for road vehicles

Abstract: An anti-roll bar assembly (10) for a motor vehicle having an anti-roll bar (12) with a pair of end portions (16) extending generally longitudinally of the vehicle interconnected by a central portion (14) extending transversely of the vehicle, is mounted with respect to the vehicle by means of a pair of bearing assemblies (30) which engage the end portions (16) of the anti-roll bar (12) intermediate of the ends of the end portions (16), the bearing assemblies (30) permitting pivotal movement of the end portions (16) about a common axis transverse to the longitudinal axis of the vehicle.

Description: The present invention relates to anti-roll bar assemblies for road vehicles. In conventional road vehicles, it is normal practice to interconnect the suspensions of the wheels on a common axle by means of an anti-roll bar, which works in torsion to restrict relative vertical movement of the wheels, thereby reducing the roll of the vehicle, particularly on cornering. Conventional anti-roll bars have a pair of end portions one connected to each wheel of the vehicle, the end portions extending substantially longitudinally of the vehicle and being connected by a central portion extending transversely of the longitudinal axis of the vehicle. The anti-roll bar is mounted to the vehicle by means of one or more compliant mountings which engage the central transverse portion of the bar, for example as disclosed in EP0044579 and US3033587. The anti-roll bar is thereby permitted to rotate freely about the axis of its central portion. With conventional anti-roll bars, because of space constraints, it is possible that the longitudinally extending portions of the bar are of a significant length. In order to prevent flexing of these longitudinal extending portions, the bar has to be of a substantial cross-section with consequent weight penalties. FR-A-2466358 (on which the preamble of claim 1 is based) discloses an anti-roll bar assembly in which bearing assemblies engage the longitudinally extending portions of the bar to permit the pivoting of the end portions about a common transverse axis. While assemblies of this construction provide significant advantages as disclosed below, serious build problems result from tolerance build-up in the support structure, particularly where the longitudinal end portions are relatively short. The present invention provides a modified anti-roll bar assembly which will permit a reduction in the diameter of the bar that may be used, with a consequent weight saving while overcoming the disadvantages of previously known assemblies. According to one aspect of the present invention an anti-roll bar assembly for a motor vehicle comprises; an anti-roll bar with a pair of end portions interconnected by a central portion, each end portion extending substantially longitudinally of the vehicle and being connected at its free end to one of a pair of wheels mounted on a common axle of the vehicle, the central portion of the bar extending transversely to the longitudinal axis of the vehicle, each of the end portions of the anti-roll bar being mounted, intermediate of its free end and the central portion of the bar, with respect to the vehicle by means of a bearing assembly, the bearing assemblies being mounted on a common axis transverse to the longitudinal axis of the vehicle to permit pivotal movement of the end portions of the anti-roll bar about the common axis; characterised in that the bearing assemblies are adjustable transverse of the longitudinal axis of the vehicle. With the above described assembly, when the suspensions of the wheels are moving up or down together, the bearing assemblies will permit the bar to pivot about the common transverse axis. However, differential movement of the wheels will be opposed by torsion of the anti-roll bar and also flexing of the portions of the bar between the bearings and the wheels. As the bar is mounted part way along the longitudinally extending end portions of the bar, the length between the supported part of the bar and the wheel may be reduced, so that the diameter of the bar and thus its weight may also be reduced. Adjustment of the bearing assemblies transverse to the longitudinal axis of the vehicle will accommodate tolerance build-up in the support structure of the vehicle to which the bearings are secured. According to a further preferred embodiment, the anti-roll bar is mounted by means of spherical bearings. The invention is now described, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is an isometric view of one side of an anti-roll bar assembly in accordance with the present invention; Figure 2 is a sectional isometric view of a spherical bearing assembly used in the assembly illustrated in Figure 1; Figure 3 shows a sectional side elevation of a modification to the bearing illustrated in Figure 2; Figure 4 shows a part sectional front elevation of the bearing assembly illustrated in Figure 3; Figure 5 illustrates a modification to the bearing assembly illustrated in Figure 3; and Figure 6 is a sectional side elevation of an alternative form of bearing for use in the assembly illustrated in Figure 1. Figure 1 shows one side of an anti-roll bar assembly 10, the other side being a mirror image of that shown. The anti-roll bar assembly 10 comprises an anti-roll bar 12 having a central portion 14 which extends transversely of a longitudinal axis of the vehicle. An end portion 16 is provided at each end of the central portion 14, the end portion 16 extending longitudinally of the vehicle. The free end 18 of each end portion 16 is connected to a suspension arm 20 of one of the wheels on a common axle of the vehicle. The suspension arms 20 are pivotally mounted to opposite sides of a crossbeam 24 which is secured transversely of the longitudinal axis of the vehicle. The ends 18 of the bar 12 are connected to the suspension arms 20 by means of bushes, ball joints or other similar means 26 which will permit relative pivotal movement therebetween, as the suspension arm 20 moves upwards and downwards. The anti-roll bar 12 is mounted with respect to the cross beam 24 by means of a pair of bearing assemblies 30, the bearing assemblies 30 engaging the longitudinally extended end portions 16 of the bar 12 on a common axis transverse to the longitudinal axis of the vehicle, one bearing assembly 30 on either side of the cross beam 24. In order to accommodate tolerance variations in the build of the cross beam 24, the bearing assemblies 30 are preferably provided with means for transverse adjustment. As illustrated in greater detail in Figure 2, the bearing assemblies 30 comprise a two-part housing 32, the parts 34 and 36 of the housing 32 being clamped together and to the cross beam 24, by means of a pair of bolts which engage through holes 38 in the parts 34 and 36. A housing 32 defines a central aperture 40 of square configuration with rounded corners. Square grooves 42, 44 are provided in the edges of the housing 32 defining the aperture 40. The grooves 42 in the edges of the housing defining the sides of aperture 40 perpendicular to the holes 38, are deeper than the grooves 44 lying parallel to the holes 38. A bearing block 50 of square section is located in the grooves 42 and 44, the bearing block 50 slidably engaging the bases of grooves 44, the deeper grooves 42 permitting the bearing block 50 to move transversely to the longitudinal axis of the vehicle. Preferably, the grooves 42 permit up to 6 mm of movement of the bearing block 50 from one extreme to the other, in order to accommodate tolerance build-up of ± 3mm in the build of the cross beam 24. The bearing block 50 is made of glass reinforced nylon and defines a part spherical bearing aperture 54. The bearing block 50 is formed in two halves 56, 58, the halves being assembled together with the split 59 parallel to the bases of grooves 44. A collar 60 is secured on each of the longitudinally extending end portions 16 of the bar 12 intermediate of their connection to the suspension arms 20 and the central portion 14. The outer diameter of the collar 60 defines a part spherical bearing formation 62 which corresponds to the bearing aperture 54 of the bearing block 50. The collar 60 is located longitudinally of the end portion 16 of the bar 12 in any suitable manner, for example by swaging, heat shrinking or bonding. The spherical bearing formations 62 will thus permit the anti-roll bar 12 to pivot around the common axis of the bearing assemblies 30, from the full bump position shown in dashed line in Figure 1 to the full rebound position illustrated in broken line in Figure 1, when the suspension arms 20 on either side of the vehicle move upwardly and downwardly together, thus permitting full movement of the vehicle suspension. However, when one suspension arm 20 moves relative to the other, the torsional rigidity of the bar 12 and reaction of the forces at the bearing assemblies 30, will oppose relative movement of the suspensions arms 20, thereby reducing roll of the vehicle. In the modification illustrated in Figures 3 and 4, the nylon block 50 is replaced by an elastomeric bush 150. The elastomeric bush 150 has a pair of nylon inserts 151, each insert 151 being secured to an opposite edge of the elastomeric block 150. The nylon inserts 151 engage in the grooves 44 or the two-part housing 32, to permit sliding of the elastomeric bush 150 transversely of the longitudinal axis of the vehicle. The elastomeric bush 150 defines a bearing aperture 154 which engages about the anti-roll bar 12. An upset portion 160 on the anti-roll bar 12 engages an arcuate recess 155 on the internal diameter of the bearing aperture 154, to locate the bearing assembly 30 longitudinally of the anti-roll bar 12. The elastomeric bush 150 is designed to permit relatively free pivoting of the anti-roll bar in the bearing assembly 30, as the two sides of the suspension move upwards and downwards together. Such pivoting movement is permitted by differential compression of the two sides of the bush 150, that is the upper part of a first side and the lower part of a second side of the bush 150 will be in compression while the lower part of the first side and the upper part of the second side of the bush 150 are in extension. The bush 150 will however oppose parallel movement of the anti-roll bar 12 in the bearing assembly 30, when the two sides of the suspension move relative to one another. Rigid plastics or metal reinforcing elements may be embedded in the elastomeric bush 150, in order to provide the desired characteristics. While in the above embodiment nylon inserts are provided on the elastomeric bush 150 for sliding engagement of the housing 32, any suitable rigid plastics or metal inserts may be used. In accordance with a further modification illustrated in Figure 5, the elastomeric bush 150 may be located longitudinally of the anti-roll bar 12 between a pair of upset portions 260, the upset portions 260 being spaced axially of one another. In the modification illustrated in Figure 6, a bearing assembly 70 is clamped to each of the longitudinally extending portions 16 of the bar 12, by means of a clamping assembly 72 comprising a pair of shells 74, 76 which are clamped together by means of bolts 78. A spigot 80 is secured to the clamping assembly 72, so that it extends transversely to the axis of the bar 12. The spigot 80 is pivotally located in a bush 82 which in turn is mounted by means of a housing 84 to the cross beam 24 of the vehicle. In similar manner to the bearing assemblies 30 described above, the bearing assemblies 70 on either side of the vehicle are mounted on the cross beam 24, so that the spigots 80 have a common axis of rotation transverse to the longitudinal axis of the vehicle. The bearing assemblies 70 will thereby permit pivoting of the anti-roll bar 12 about the transverse axis, as the suspension arms 20 move upwardly and downwardly together and will oppose relative movement of the suspension arms 20 in similar manner to the bearing assemblies 30 disclosed above. Axial movement of the spigots 80 in the bushes 82 will also accommodate transverse tolerance variations in the build of the cross beam 24.

Claims: An anti-roll bar assembly (10) for a motor vehicle comprising an anti-roll bar (12) with a pair of end portions (16) interconnected by a central portion (14), each end portion (16) extending substantially longitudinally of the vehicle and being connected at its free end (18) to one of a pair of wheels mounted on a common axle of the vehicle, the central portion (14) of the bar (12) extending transversely to the longitudinal axis of the vehicle, each of the end portions (16) of the anti-roll bar (12) being mounted, intermediate of its free end (18) and the central portion (14) of the bar (12), with respect to the vehicle by means of a bearing assembly (30), the bearing assemblies (30) being mounted on a common axis transverse to the longitudinal axis of the vehicle, to permit pivotal movement of the end portions (16) of the anti-roll bar (12) about the common axis; characterised in that the bearing assemblies (30) are adjustable transverse of the longitudinal axis of the vehicle. An anti-roll bar assembly (10) according to Claim 1 characterised in that the bearing assemblies (30) comprise a housing (32) in which a bearing block (50) is mounted, the bearing block (50) being slidable with respect to the housing (32) in a direction transverse to the longitudinal axis of the vehicle. An anti-roll bar assembly (10) according to Claim 2 characterised in that said housing (32) is of two-part construction, the parts (34, 36) being clamped together and to a support structure (24) of the vehicle to define a central aperture (40), the edges of the housing defining the aperture (40) being grooved, the bearing block (50) being slidably located in said grooves (42, 44). An anti-roll bar assembly (10) according to any one of Claims 2 or 3 characterised in that the bearing block (50) is formed in two parts (56, 58) split normal to the sliding axis of the bearing block (50). An anti-roll bar assembly (10) according to any one of the preceding claims characterised in that the bearing assemblies (30) provide spherical bearings. An anti-roll bar assembly (10) according to Claim 5 characterised in that a bearing block (50) defines a central bearing aperture (54), the aperture (54) being of part spherical configuration. An anti-roll bar assembly (10) according to Claim 6 characterised in that a collar (60) is mounted on each end portion (16) of the anti-roll bar (12) intermediate of the end (18) thereof connected to the wheel and the central portion (14) of the anti-roll bar (12), the external diameter of the collar (60) defining a spherical bearing formation (62) corresponding to the bearing formation of the bearing assembly (30). An anti-roll bar assembly (10) according to Claim 7 characterised in that the collar (60) is swaged, heat shrunk or bonded to the end portion (16) of the anti-roll bar (12). An anti-roll bar assembly (10) according to any one of Claims 1 to 4 characterised in that the bearing assembly (30) includes an elastomeric bush (150). An anti-roll bar assembly (10) according to Claim 9 characterised in that the elastomeric bush (150) has rigid inserts (151) for slidably engaging a housing (32). An anti-roll bar assembly (10) according to Claim9 or 10 characterised in that the elastomeric bush (150) is located longitudinally of the anti-roll bar (12) by one or more upset portions (160; 260) on the anti-roll bar (12). An anti-roll bar assembly (10) according to Claim 1 characterised in that the bearing assembly (72) is clamped to the end portion (16) of the anti-roll bar (12) intermediate of its end (18) connected to the wheel and the central portion (14) of the anti-roll bar (12), the bearing assembly (72) having a spigot (80) which extends transverse to the axis of the anti-roll bar (12), the spigot (80) rotatably engaging a bearing formation (82) mounted on a support structure (24) of the vehicle, said spigots (80) of the bearing assemblies (72) mounted on each end portion (16) of the anti-roll bar (12) having a common axis of rotation, said axis being transverse to the longitudinal axis of the vehicle. An anti-roll bar assembly (10) according to Claim 12 characterised in that at least one of the spigots (80) is slidable axially in its associated bearing (82).

Inventors: ADKINS DAVID PAUL, GRIFFITHS TREVOR JOHN, POVEY ROBERT DAVID, ADKINS, DAVID PAUL, GRIFFITHS, TREVOR JOHN, POVEY, ROBERT DAVID
Applicants: JAGUAR CARS, JAGUAR CARS LIMITED
Application year: 1996
Main classification: B60G21
IPC codes: B60G21, F16C11