DE3934238A1 - Vehicle wheel suspension with elastically mounted guide - has variable vol. chamber, acted on by lateral wheel forces, pressurising under-steer effecting chamber in elastic mount - Google Patents

Abstract

A vehicle wheel suspension has a wheel guide (18), linked to the vehicle body by an elastic mount (12). A first variable vol. chamber (60,62), when pressurised creates an under-steer effect on the wheel. The first chamber is connected to and pressurised by a second variable vol.chamber (56,58), operated by the lateral wheel forces. ADVANTAGE - The two chambers can be incorporated into one unit with no separate components needed.

Description

The invention relates to a wheel suspension for motor vehicles, according to the Preamble of claim 1.

Such a wheel suspension is, for example, EP-A 2 21 547 ent acceptable. Here is a Querlen serving as a wheel guide element ker, which is attached to the body of the motor vehicle via two elastic bearings steers, a bearing is provided with two variable-volume chambers, the one hydraulic unit with one pump and several control valves can be acted upon. Hydraulically adjusted via this Bare bearings should have a defined self-steering behavior of the wheel suspension be effected. There is an electronic control unit with means that the control valves are actuated in certain driving conditions will.

Furthermore, DE-OS 37 32 088 has a wheel suspension with a Ver Bundlenkerachse known as a wheel guide element, in which the two between the longitudinal links and the structure provided elastic bearings each have a volume-variable chamber with a line are connected. A shut-off valve is arranged in the line, which is connected to the braking system of the motor vehicle and connects the two chambers only when the brake is applied. By arranging the two volume-variable chambers in the elastic bearings should then be self-steering behavior, if there are different coefficients of friction between the wheels and the driver when braking path occur. In the rest of driving, especially in curves, that is Control valve closed so that no influence on driving behavior or a targeted self-steering occurs. In a structurally simple way the self-steering caused when braking is not by means of a hydraulic mixing device with a pump, with valves and an electronic  control unit with the appropriate sensors, but via the Reaction forces occurring when braking due to volume displacement in one chamber.

A rubber-metal bearing is also known from DE-OS 27 48 193 such an asymmetrical design that the inner and outer me Tall bushing of the bearing when introducing axial forces in a targeted predetermined direction are displaced radially against each other. When on Construction of such rubber-metal bearings for example in a compound kerachse can self-steer in the direction when driving through curves Toe-in or understeer can be effected. The effect of such bearings however, there are limits set by structural and constructive requirements such as Torsional stiffness, degree of elasticity, available space, Etc.

The object of the invention is a wheel suspension of the generic type Kind in such a way that a ge without external pressure medium source targeted, effective self-steering behavior, especially when passing through driving curves (with lateral forces), is achievable and / or that Use of the suspension and roll comfort to improve, lengthways elastic bearings undesirable self-steering movements can be avoided.

This object is achieved with the characterizing features of claim 1 solved. Advantageous and expedient training The invention can be found in the other claims.

According to the invention it is proposed to be one by side forces on the wheel provided volume-variable chamber to be provided, which constantly with the pressurizable chamber connected within the elastic bearing is. This provides several advantages in a surprisingly simple way achieved. First of all, it is possible to control self-steering without external To cause pressure medium source, in particular a hydraulic pump, by side forces acting on the wheel in one volu variable chamber generate an increase in pressure on the other volume-variable chamber in the sense of a self-steering behavior effects by shifting the wheel guide element accordingly  becomes. The degree of self-steering can be determined by dimensioning the volume-variable chambers (hydraulic translation) in the desired Dimensions are determined. In addition, the permanent connection a higher bearing between the two volume-changing chambers elasticity combined with improved hydraulic damping. The damping can, if necessary, by a suitable design of the Connection between the chambers causing overflow openings or Lines and / or can be set by a throttle.

According to the features of claims 2 and 3, the volumenve marginal chambers formed in total in the elastic bearing be and interact according to the invention through overflow openings. At lateral forces acting on the wheel guide element, in particular when Driving through curves becomes a volume-variable chamber compressed and the hydraulic fluid into the other, self-steering acting chamber displaced. Ent can be particularly advantageous speaking claim 3 four volume-variable chambers in the elastic bearings can be provided so that with lateral forces different signs also corresponding self-steering movements be initiated.

According to claim 4, the volu operated by the side forces variable chamber also in the form of an actuator with a Coupling rod between the wheel carrier and body of the motor vehicle arranges and via a corresponding line to the other chamber be closed. As a result, the side forces or those associated with it which elastokinematic displacements of the wheel guide element telbar removed and converted into a corresponding self-steering. Due to the spatial separation of the two variable-volume chambers the structure of the elastic bearing is simplified or its required installation space reduced. For wheel guide elements with two elastic bearings, for example a torsion beam axle executed according to the features of claim 5 and with be connected. By correspondingly addressing the Both bearings will be a particularly good, effective self-steering behavior realized. The same applies according to claim 6 for  Wheel suspensions with elastic bearings in which the volumenver changeable chambers are integrated as a whole.

A structurally particularly advantageous embodiment of the elastic La gers can be found in the features of claims 7 and 8. Further can according to claim 9 in a particularly inexpensive and operational safer ge the actuator by a rubber-elastic bellows be educated.

Two embodiments of the invention are described below with others Details explained in more detail. The schematic drawing shows in

Figure 1 is a plan view of a wheel suspension with a torsion beam axle, which is articulated with two elastic bearings on the structure of the motor vehicle.

FIG. 2 shows an elastic bearing according to FIG. 1 in a horizontal section, with tegged variable-volume chambers;

Fig. 3 shows a wheel suspension with a torsion beam axle with two ela-elastic bearings and two actuators connected to the wheel carriers via coupling rods.

Fig. 1 shows schematically a wheel suspension for the rear wheels of a motor vehicle with a torsion beam axle 10 , which is connected via two elastic bearings 12 , 14 in mirror image identical construction to the construction 16 of the motor vehicle. The torsion beam axle 10 is composed essentially of two trailing arms 18 , 20 , which are connected to one another in a corner-rigid manner via a torsionally flexible, rigid cross strut 22 . Attached to the trailing arms at their free ends are each a wheel carrier 24 , 26 on which the rear wheels 32 , 34 of the motor vehicle are mounted via journals 28 , 30 .

Passes the motor vehicle, the forward direction of travel is indicated by the arrow 36 , a right turn, so acts on the wheel guide element or the torsion beam axis 10, a lateral force F _S , which generates longitudinal forces in the elastic bearings 12 , 14 , which the wheel suspension in the elastokinematic Tension the area to an undesired self-steering movement in the sense of oversteer.

In order to counteract this, the elastic bearings 12 , 14 are designed as shown in FIG. 2. So the elastic bearing 12 consists of an inner sleeve 37 with two end flanges 38 , 40 , on which the trailing arm 18 is fastened by means of a screw bolt 42 and a threaded nut 44 . Vulcanized onto the sleeve 37 are two ring-shaped, rubber-elastic partition walls 46 , 48 , which are firmly connected on their outer circumference to a metallic bearing ring 50 . The bearing ring 50 is welded to a bracket 52 , not shown, which is screwed to the body of the motor vehicle.

Between the annular partition walls 46 , 48 , an annular space is formed, which is divided into two volume-variable chambers 56 , 58 by two partition walls 54 running parallel to the screw bolt 42 (only one partition wall 54 is visible on the cross-sectional drawing in FIG. 2). Each chamber 56 , 58 extends over a circumferential section of approximately 170 °. The partitions 54 are formed directly on the ring-shaped partitions 46 , 48 and connected to the bearing ring 50 or the inner sleeve 37 in a liquid-tight manner.

A further volume-variable chamber 60 , 62 is formed between the partition walls 46 , 48 and their adjacent end flange 38 , 40 , each of which is delimited by a fabric-reinforced membrane ring 64 , 66 . The membrane rings 64 , 66 are liquid-tightly attached to the flanges 38 , 40 and to ring collars 68 , 70 of the bearing ring 50 .

The front in the vehicle longitudinal direction chamber 58 is connected via an overflow opening 72 with the variable volume, in the vehicle transverse direction inside, chamber 62 , while the rear chamber in the vehicle longitudinal direction 56 via an overflow opening 74 with the outside in the vehicle transverse direction chamber 60 a related party is. The chambers 56 , 58 , 60 , 62 are filled with a hydraulic fluid.

When driving through a right-hand bend, as described above, it generates the lateral force F _S, a force component which acts on the elastic bearing 12 in the direction of arrow 76 against the direction of travel 36 . The elasticity of the bearing compresses the volume-changing chamber 58 and displaces part of the hydraulic fluid contained therein via the overflow opening 72 into the chamber 62 . This causes a displacement of the trailing arm 18 in the region of its articulation point in the direction of arrow 78 , which corresponds to a countersteering or an understeering tendency. This counter-steering effect is supported by the fact that at the same time the chamber 56 located at the rear in the direction of travel increases in volume, hydraulic fluid being drawn off from the chamber 60 opposite the chamber 62 .

The same counter-steering effect in the direction of arrow 78 also occurs on the mirror-image of the same elastic bearing 14 , in which a force component acting in the direction of travel in the chamber 56 causes an increase in pressure, which, however, due to the mirror-image arrangement on the overflow opening 74, a pressure increase in volume variable chamber 60 causes. Here too, the bearing point of the trailing arm 20 is shifted in the direction of the arrow 78 at the lateral force F _S. Overall, this corresponds to self-steering in the direction of understeering. When driving through a left-hand curve, the forces act with the opposite sign (opposite to the directions of force shown), which causes a self-steering movement in the opposite direction.

Fig. 3 shows a further embodiment with a composite handlebar axis 80 corresponding to the construction described in Fig. 1, with elastic bearings 82 , 84 which are connected to the structure, not shown, via horizontal and transverse screws 86 , 88 . The elastic bearings 82 , 84 each have a volume-changeable chamber 90 , 92 lying in the front in the vehicle longitudinal direction and a volume-changing chamber 94 , 96 located at the rear, which are delimited by lateral rubber-elastic ring walls. The respective chambers 90 , 94 and 92, 96 are separated from one another by axially extending partition walls, not shown.

On the attached to the trailing arms of the torsion beam wheel carriers 98 , 100 each have a substantially transverse coupling rod 102 , 104 is articulated, which is connected to a rigid bellows 106 , 108 each. The bellows 106 , 108 are attached to another at a fixed to the structure of the motor vehicle retaining flange 110 be. The bellows as control elements form variable-volume chambers 112 , 114 , which are connected via lines 116 , 118 and 120 , 122 to the variable-volume chambers 90 , 92 , 94 , 96 . The left-hand chamber 112 seen in the direction of travel is connected via the line 116 to the chamber 90 of the left elastic bearing 82 lying in the front in the vehicle longitudinal direction and via the branch line 118 to the rear chamber 96 of the elastic bearing 84 in the vehicle longitudinal direction on the right-hand side of the vehicle . Likewise, the right-hand chamber 114 is connected via line 120 to the front chamber 92 of the right bearing 84 and the rear chamber 94 of the left bearing 82 . The chambers 90 , 92 , 94 , 96 and the bellows 106 , 108 are in turn filled with hydraulic fluid.

When driving through a right-hand bend, for example, a side force F _S in turn acts on the torsion beam axle 80 as a wheel guiding element, a pressure increase being caused by the force components acting in the axial direction and due to the elasticity of the bearings 82, 84 in the volume-variable chambers 90 , 96 , which lines on the cables 116 , 118 propagates to the control element or the chamber 112 and now causes a counter-steering torque via the coupling rod 102 , which leads to an understeering tendency of the twist beam axle. With an opposite sign acting side force F _S , the chambers 92 , 94 are pressurized, whereby the rubber-elastic bellows 108 is actuated via the lines 120 , 122 and a counter steering torque is generated via the coupling rod 104 .

The invention is not limited to the exemplary embodiments shown. So can be used as a wheel guide, a wishbone or a single link, the elastic or the rule's bearings are aligned according to the force components occurring from the side forces F _S. Possibly. In a manner known per se, check valves could be provided in lines 116 , 120 or 118 , 122 , which also contribute to targeted self-steering through appropriate control (e.g. when braking or accelerating) (similar to DE-OS 37 32 088) .

Regarding the proposed bearings 12 , 14 ( FIGS. 1 and 2) and 82, 84 ( FIG. 3) with the actuating elements or bellows 106 , 108, it can generally be stated that the variable-volume chambers or their boundary walls are to be designed so that they are volume-rigid the required pressure increases will be sufficient. For example, these boundary walls can be fabric-reinforced, fiber-reinforced, or even made of metal (e.g. bellows 106 , 108 ).

Claims (9)

1. Wheel suspension for motor vehicles, with at least one wheel-guiding element which is directed to the body via at least one elastic bearing and the bearing has a volume-variable, pressurizable chamber which can be connected to a pressure medium source to achieve a self-steering movement, characterized in that that the pressure medium source is a volume-variable chamber ( 56 , 58 ; 90 , 92 , 94 , 96 ) actuated by side forces on the wheel, which is connected to the pressurizable chamber ( 60 , 62 ; 112 , 114 ). 2. Wheel suspension according to claim 1, characterized in that the elastic bearing ( 12 , 14 ) has at least two interconnected chambers ( 56 , 60 and 58 , 62 ), of which essentially one in the vehicle longitudinal direction and the other in the vehicle transverse direction (side forces F _S ) is exposed to acting forces. 3. Wheel suspension according to claims 1 and 2, characterized in that the elastic bearing ( 12 , 14 ) has four chambers ( 56 , 58 , 60 , 62 ), of which two essentially act in the vehicle longitudinal direction and two in the vehicle transverse direction Forces - but with opposite signs - are exposed, whereby two non-unidirectional chambers ( 56 , 60 and 58 , 62 ) are connected to each other. 4. Wheel suspension according to claim 1, characterized in that the volume-variable chamber ( 112 , 114 ) in the form of an actuating element ( 106 , 108 ) with an articulated coupling rod ( 102 , 104 ) between the wheel carrier ( 98 , 100 ) and the structure ( 110 ) is arranged. 5. Wheel suspension according to claim 4, with a wheel guide element (Ver bundlenkerachse) with at least two elastic bearings, characterized in that the two elastic bearings ( 82 , 84 ) one in the direction of travel in front and one in the direction of travel rear volume variable chamber ( 90 , 94 and 92 , 96 ), that each wheel carrier ( 98 , 100 ) is coupled to an adjusting element ( 106 , 108 ) and that each adjusting element is connected to the front chamber ( 90 , 92 ) of the same wheel side and the rear chamber ( 94 , 96 ) of the other wheel side is connected. 6. Wheel suspension according to one or more of claims 1 to 3, with a wheel guiding element with at least two elastic bearings, characterized in that volume in both elastic bearings variable chambers are formed. 7. Wheel suspension according to one or more of the preceding Ansprü surface, characterized in that the elastic bearing ( 12 ) has two annular, rubber-elastic partitions ( 46,48 ) which comprise a sleeve ( 37 ) with end flanges ( 38 , 40 ) and whose outer peripheral regions are connected to a bearing ring ( 50 ) and that between the end flanges ( 38 , 40 ) and the bearing ring ( 50 ) arranged membrane rings ( 64 , 66 ) limit the volume-variable chambers ( 60 , 62 ). 8. Wheel suspension according to claim 7, characterized in that the annular chamber lying between the partition walls ( 46 , 48 ) is divided into two volu-variable chambers ( 56 , 58 ) which are diametrically opposed and that in the partition walls ( 46 , 48 ) overflow openings gene ( 72 , 74 ) are provided, each connecting a semi-annular chamber ( 56 , 58 ) with a chamber ( 60 , 62 ) bounded by the membrane rings ( 64 , 66 ). 9. Wheel suspension according to one or more of the preceding Ansprü surface, characterized in that the actuating element ( 106 , 108 ) is formed by a rigid bellows.