Independent suspension and motor vehicle

Abstract

The present invention relates to an independent suspension (1) for a motor vehicle (2), comprising a wheel carrier (3) with a wheel axis (4) and comprising a semi-trailing arm (5). Here, it is essential to the invention - that the wheel carrier (3) comprises a first rubber–metal bearing (6), a second rubber–metal bearing (7) and a third rubber–metal bearing (8), via which bearings the wheel carrier (3) is connected to the semi-trailing arm (5), - that the first rubber–metal bearing (6) is situated in front of the wheel axis (4) of the wheel carrier (3) in the direction of travel (9) and the second rubber–metal bearing (7) is situated behind and below the wheel axis (4) of the wheel carrier (3) in the direction of travel (9), - that the third rubber–metal bearing (8) is situated behind and above the wheel axis (4) of the wheel carrier (3) in the direction of travel (9), - that the first rubber–metal bearing (6) is softer in the radial direction than the second rubber–metal bearing (7) in the radial direction and the third rubber–metal bearing (8) in the radial direction. As a result, significantly improved driving behaviour can be achieved.

Description

[0001] Independent suspension and motor vehicle

[0002] The present invention relates to an independent wheel suspension for a motor vehicle having a wheel carrier with a wheel axle and with a semi-trailing arm, according to the preamble of claim 1. The invention also relates to a motor vehicle having such an independent wheel suspension.

[0003] DE 103 21 878 A1 discloses a generic independent wheel suspension for a motor vehicle, comprising a wheel carrier with a wheel axle and a semi-trailing arm, which has a first bearing, a second bearing, and a third bearing, via which the semi-trailing arm can be mounted on a body of the motor vehicle. The first bearing and the second bearing are arranged in front of the wheel axle of the wheel carrier in the direction of travel. The use of elastic rubber-metal bearings, which consist at least partially of two concentric rings or a ring and a bolt, between which an elastomer body is permanently integrated at least partially, is intended to enable greater driving comfort, particularly in the presence of lateral, longitudinal, and vertical forces.

[0004] DE 103 21 877 A1 discloses an independent wheel suspension with a wheel-guiding, longitudinal, or twist link mounted on a vehicle body, which has a wheel carrier mounted in several elastic pivot bearings. The elastic pivot bearings consist, at least in some areas, of two concentric rings or a ring and a bolt, in which an elastomer body is permanently integrated, at least in some areas. For this purpose, the wheel carrier is supported on the control arm in front of the wheel axle via at least one elastic control bearing and behind the wheel axle by means of a pendulum plate. This pendulum plate, in turn, incorporates four elastic pivot bearings, the fastening elements of which are fastened half to the control arm and half to the wheel carrier. This is also intended to enable greater driving comfort.

[0005] DE 198 16 804 A1 discloses an independent wheel suspension in a semi-trailing arm design with a wheel-guiding wishbone elastically mounted at at least two points on the vehicle body and a rod link that is laterally offset from the wishbone and the vehicle body toward the center of the vehicle. The rod link is mounted on both sides between the vehicle body and the wishbone in rigid ball joints and is a maximum of half the length of the mean length of the wishbone. Both links lie approximately in the same plane, creating an independent wheel suspension that, despite the elastic rubber-metal mounting of the semi-trailing arm, does not oversteer due to lateral forces.

[0006] DE 10 2015 201 338 A1 discloses a semi-trailing arm axle for suspending a wheel on a motor vehicle body. It includes a semi-trailing arm that can be articulated to a wheel carrier and a tie rod, particularly an active one, for pivoting the wheel carrier and supported on the semi-trailing arm. This is intended to improve ride comfort and reduce noise propagation to the passenger compartment.

[0007] DE 10 2016220 925 A1 discloses a wheel carrier comprising a base element supporting a wheel bearing, a first linkage connection area having at least one rubber-metal bearing for detachable connection to a link, and a second linkage connection area having at least one bearing point for detachable connection to a link. The two linkage connection areas are designed as separate components and are detachably connected to the base element via fastening means. This is intended to create a wheel carrier that, on the one hand, requires little installation space and, on the other hand, provides modularity and reduces the variance of components.

[0008] The disadvantage of the independent wheel suspensions known from the state of the art is that the driving characteristics of the independent wheel suspensions used can be improved.

[0009] The present invention addresses the problem of providing an improved or at least an alternative embodiment for an independent wheel suspension of the generic type, which in particular shows improved driving behavior.

[0010] This problem is solved according to the invention by the subject matter of independent claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0011] The present invention is based on the general idea of ​​designing an independent wheel suspension for a motor vehicle for the first time with a wheel carrier separate from a semi-trailing arm and mounting this wheel carrier on the semi-trailing arm via three specially designed and arranged rubber-metal bearings, thereby achieving significantly increased ride comfort and significantly improved driving dynamics. The independent wheel suspension for a motor vehicle according to the invention has the aforementioned wheel carrier with a wheel axle and a semi-trailing arm, wherein the wheel carrier according to the invention has a first rubber-metal bearing, a second rubber-metal bearing and a third rubber-metal bearing, via which the wheel carrier is connected to the semi-trailing arm. The first rubber-metal bearing is arranged in front of the wheel axle of the wheel carrier in the direction of travel, while the second rubber-metal bearing is arranged behind and below the wheel axle of the wheel carrier in the direction of travel.The third rubber-metal bearing, in turn, is arranged behind and above the wheel axle of the wheel carrier in the direction of travel. The first rubber-metal bearing is softer in the radial direction than the second rubber-metal bearing and the third rubber-metal bearing. In this case, "softer" means that the first rubber-metal bearing has a lower modulus of elasticity than the third rubber-metal bearing and the second rubber-metal bearing. The second and third bearings are radially very stiff compared to the first rubber-metal bearing, which ensures good camber rigidity. Until now, the wheel carrier, wheel axle, and semi-trailing arm were formed as a single piece, preventing any relative movement of the wheel carrier to the semi-trailing arm. This had a negative impact on handling and driving dynamics.By decoupling the wheel carrier from the semi-trailing arm by means of the three aforementioned rubber-metal mounts and by the selected positions of the individual rubber-metal mounts as well as the reduced rigidity of the first rubber-metal mount compared to the second and third rubber-metal mounts, improved driving dynamics can be achieved, in particular reducing understeering behavior when cornering and braking. The provided positive toe-in change makes it easier to bring the vehicle back under control even if it skids by releasing the throttle and correcting the steering. The increased toe-in on the rear axle of the vehicle due to the independent wheel suspension according to the invention makes it possible to achieve overall smoother handling of the vehicle, with the rear of the vehicle having more grip during acceleration and rapid load changes.

[0012] In an advantageous development of the independent wheel suspension according to the invention, the first rubber-metal bearing is arranged in a closed bearing eye of the semi-trailing arm. Such an arrangement of the first rubber-metal bearing in a corresponding bearing eye allows for particularly precise mounting of the first rubber-metal bearing, whereby an axis of the first rubber-metal bearing or the bearing eye can also be aligned deviating from a horizontal plane, thus exhibiting a Z-shaped alignment. This allows for a slightly inclined alignment around the vertical and transverse axes, which offers the possibility of selecting an optimal position for the bearing with regard to assembly and functionality. Furthermore, the first rubber-metal bearing can be pressed into the bearing eye and thus fixed.

[0013] In a particularly preferred embodiment of the independent wheel suspension according to the invention, the semi-trailing arm has a first upper arm and a second upper arm arranged separately therefrom, which touch at their free ends in an area where the third rubber-metal bearing is also arranged. This makes it possible to arrange the third rubber-metal bearing according to the invention behind and above the wheel axle of the wheel carrier, whereby the softer first rubber-metal bearing with respect to the second and third rubber-metal bearings - in each case in the radial direction - can improve the driving dynamics and general handling of a motor vehicle equipped with such an independent wheel suspension. The first upper arm and the second upper arm are formed integrally with the semi-trailing arm, for example by casting.

[0014] The second rubber-metal bearing is expediently arranged on a lower section of the semi-trailing arm. The first, second and third rubber-metal bearings of the wheel carrier are connected to the semi-trailing arm in a forward direction in the direction of travel, which enables comparatively simple assembly. The wheel carrier is thus attached to the semi-trailing arm from behind. The second rubber-metal bearing is thus placed from behind on the lower section of the semi-trailing arm, while the third rubber-metal bearing is placed from behind on the area where the free ends of the two upper arms touch. The closed bearing eye, in which the first rubber-metal bearing is arranged, is arranged at a transition between the first upper arm and the lower section, wherein the bearing eye can be formed by a lateral formation. The closed bearing eye, i.e.its border is also formed in one piece with the semi-trailing arm.

[0015] In a particularly preferred embodiment of the independent wheel suspension according to the invention, the rubber-metal bearings are aligned with their respective axes substantially in the longitudinal direction of the vehicle. The axial stiffness of all three rubber-metal bearings is selected such that this results in longitudinal flexibility of the wheel carrier in relation to the semi-trailing arm, which was previously not possible with a one-piece semi-trailing arm and wheel carrier. This additional, soft decoupling brings significant advantages in driving comfort, particularly when driving over obstacles and on uneven roads. The individual rubber-metal bearings can also enable a relative movement between the wheel carrier and the semi-trailing arm that deviates from the respective bearing axis, which can further improve driving behavior.

[0016] In a further advantageous embodiment, two further rubber-metal bearings are arranged on the semi-trailing arm in front of the wheel axle in the direction of travel, which can be connected to a vehicle body of a motor vehicle, wherein a bearing point for supporting a coil spring is also arranged behind the wheel axle in the direction of travel. The two further rubber-metal bearings located in front of the wheel axle in the direction of travel also enable at least slight relative movement of the semi-trailing arm to the vehicle body, while the coil spring enables suspension of the vehicle body in the vertical direction relative to the semi-trailing arm. The present invention is further based on the general idea of ​​specifying a motor vehicle with an independent wheel suspension described in the previous paragraphs, whereby the advantages described with regard to the independent wheel suspension according to the invention can be transferred to the motor vehicle.Specifically, these advantages lie in significantly improved driving dynamics and ride comfort, since the independent wheel suspension according to the invention exhibits multiple times greater longitudinal compliance than conventional semi-trailing arms when subjected to longitudinal forces in the direction of travel. This multiple longitudinal compliance results from the longitudinal compliance of the three rubber-metal mounts between the wheel carrier and semi-trailing arm and the two additional rubber-metal mounts between the semi-trailing arm and the vehicle body.

[0017] In a further advantageous embodiment of the motor vehicle according to the invention, a shock absorber is provided, which is connected on one side to the semi-trailing arm and on the other side to a vehicle body and is guided through the two upper arms. This allows for a space-optimized and simultaneously protected arrangement of the shock absorber.

[0018] Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures based on the drawings.

[0019] It is understood that the features mentioned above and those to be explained below can be used not only in the respective combination specified, but also in other combinations or on their own, without departing from the scope of the invention defined by the claims. Components mentioned above and to be mentioned below of a higher-level unit, such as a device, apparatus, or arrangement, which are designated separately, may form separate parts or components of this unit or be integral areas or sections of this unit, even if this is shown differently in the drawings.

[0020] Preferred embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0021] They show, schematically,

[0022] Figure 1 is a view of an independent wheel suspension according to the invention,

[0023] Figure 2 is a representation as in Figure 1 , but additionally with disc brake, shock absorber, coil spring and stabilizer,

[0024] Figure 3 is a representation similar to Figure 2, but from a different perspective and with a rim.

[0025] According to Figures 1-3, an independent wheel suspension 1 according to the invention for a motor vehicle 2 has a wheel carrier 3 with a wheel axle 4 and a semi-trailing arm 5. In independent wheel suspensions previously known from the prior art, the wheel carrier 3 and the semi-trailing arm 5 were designed as a single piece. This is achieved differently in the independent wheel suspension 1 according to the invention, wherein the wheel carrier 3 has a first rubber-metal bearing 6, a second rubber-metal bearing 7 and a third rubber-metal bearing 8, via which the wheel carrier 3 is connected to the semi-trailing arm 5. The first rubber-metal bearing 6 is arranged in front of the wheel axle 4 of the wheel carrier 3 in the direction of travel 9, while the second rubber-metal bearing 7 is arranged behind and below the wheel axle 4 of the wheel carrier 3 in the direction of travel 9. The third rubber-metal bearing 8 is arranged in the direction of travel 9 behind and at the same time above the wheel axle 4 of the wheel carrier 3.The first rubber-metal bearing 6 is also softer in the radial direction, i.e. with lower spring stiffness, than the third rubber-metal bearing 8 and the second rubber-metal bearing 7.

[0026] The elastic rubber-metal bearings 6, 7, 8 can have two concentric sleeves or a sleeve and a bolt, into which an elastomer body is permanently integrated, at least in certain areas. This allows for significantly improved driving dynamics and a positive toe-in change, which leads to understeering behavior when cornering and braking. The increased toe-in allows for smoother driving behavior overall, with the rear of the vehicle having more roadholding during acceleration and rapid load changes. The independent wheel suspension 1 is arranged on the rear wheels of the vehicle 2.

[0027] The first rubber-metal bearing 6 is, as can be seen from Figure 1, arranged, in particular pressed, in a closed bearing eye 10 of the semi-trailing arm 5. This enables radial fixation of the first bearing 6 in the bearing eye 10. As can be clearly seen in particular from Figure 1, the bearing eye 10 is arranged at a transition between a first upper arm 11 and a lower section 14 of the semi-trailing arm 5, with the second rubber-metal bearing 7 being connected to the lower section 14 at the same time. The entire semi-trailing arm 5 is preferably formed in one piece.

[0028] The semi-trailing arm 5 also has the aforementioned first upper arm 11 and a second upper arm 12, which touch at their free ends, ie at their ends facing away from the semi-trailing arm 5, in an area 13 in which the third rubber-metal bearing 8 is also arranged.

[0029] The rubber-metal bearings 6, 7, and 8 are preferably aligned parallel with respect to their axes, although it is also conceivable for the first rubber-metal bearing 6 to be adjusted in the Z direction. Furthermore, the individual rubber-metal bearings 6, 7, and 8 are aligned with their respective axes essentially in the longitudinal direction of the vehicle.

[0030] Looking further at the semi-trailing arm 5, it can be seen that two further rubber-metal bearings 15, 16 are arranged in front of the wheel axle 4 in the direction of travel 9 and also in front of the first rubber-metal bearing 6, via which the semi-trailing arm 5 can be connected to a vehicle body (not shown in detail). The axes of the further rubber-metal bearings 15, 16 are aligned obliquely to the axes of the rubber-metal bearings 6, 7 and 8. A bearing point 17 for supporting a coil spring 18 (see Figure 3) is arranged behind the wheel axle 4 in the direction of travel 9, wherein the bearing point 17 is also formed integrally with the semi-trailing arm 5. A shock absorber 19 is also provided, which is connected on the one hand to the semi-trailing arm 5 and on the other hand to a body (not shown in detail) of the motor vehicle 2 and is also guided through the two upper arms 11, 12.

[0031] Furthermore, a connection point 20 for connecting a stabilizer 21 is arranged on the semi-trailing arm 5, wherein the stabilizer 21 is connected to the connection point 20 of the semi-trailing arm 5 via a pendulum support 22 and thus cannot transmit any moments to the semi-trailing arm 5.

[0032] All in all, significantly improved handling can be achieved with the independent wheel suspension according to the invention, wherein the connection points for connecting the independent wheel suspension 1 according to the invention to the motor vehicle 2 or its vehicle body are unchanged from previous independent wheel suspensions from the prior art, in which the wheel carrier 3 and the semi-trailing arm 5 were formed as a single piece. In particular, the multiple longitudinal compliance present in the independent wheel suspension 1 according to the invention for longitudinal forces occurring in the direction of travel 9 can significantly improve handling. The multiple longitudinal compliance results from the longitudinal compliance of the three rubber-metal bearings 6, 7, 8 between the wheel carrier 3 and the semi-trailing arm 5 and the two additional rubber-metal bearings 15, 16 between the semi-trailing arm 5 and the vehicle body.

Claims

Patent claims 1 . Independent wheel suspension (1 ) for a motor vehicle (2), - with a wheel carrier (3) with a wheel axle (4), - with a semi-trailing arm (5), characterized in - that the wheel carrier (3) has a first rubber-metal bearing (6), a second rubber-metal bearing (7) and a third rubber-metal bearing (8), via which the wheel carrier (3) is connected to the semi-trailing arm (5), - that the first rubber-metal bearing (6) is arranged in front of the wheel axle (4) of the wheel carrier (3) in the direction of travel (9) and the second rubber-metal bearing (7) is arranged behind and below the wheel axle (4) of the wheel carrier (3) in the direction of travel (9), - that the third rubber-metal bearing (8) is arranged in the direction of travel (9) behind and above the wheel axle (4) of the wheel carrier (3), - that the first rubber-metal bearing (6) is softer in the radial direction than the second rubber-metal bearing (7) in the radial direction and the third rubber-metal bearing (8) in the radial direction.

2. Independent wheel suspension (1) according to claim 1, characterized in that the first rubber-metal bearing (6) is arranged in a closed bearing eye (10) of the semi-trailing arm (5).

3. Independent wheel suspension (1) according to claim 1 or 2, characterized in that the semi-trailing arm (5) has a first upper arm (11) and a second upper arm (12) which touch at their free ends in a region (13) in which the third rubber-metal bearing (8) is arranged.

4. Independent wheel suspension (1) according to one of the preceding claims, characterized in that the second rubber-metal bearing (7) is arranged on a lower section (14) of the semi-trailing arm (5).

5. Independent wheel suspension (1) according to claim 2, 3 and 4, characterized in that the bearing eye (10) is arranged at a transition between the first upper arm (11) and the lower section (14).

6. Independent wheel suspension (1) according to one of the preceding claims, characterized in that the rubber-metal bearings (6, 7, 8) are aligned with their respective axes substantially in the longitudinal direction of the vehicle.

7. Independent wheel suspension (1) according to one of the preceding claims, characterized in that two further rubber-metal bearings (15, 16) are arranged on the semi-trailing arm (5) in the direction of travel (9) in front of the wheel axle (4), which can be connected to a vehicle body.

8. Independent wheel suspension (1) according to one of the preceding claims, characterized in that a bearing point (17) for supporting a coil spring (18) is arranged on the semi-trailing arm (5) in the direction of travel (9) behind the wheel axle (4).

9. Motor vehicle (2) with an independent wheel suspension (1) according to one of the preceding claims.

10. Motor vehicle (2) according to claim 9 with an independent wheel suspension (1) at least according to claim 3, characterized in that a shock absorber (19) is provided which is connected on the one hand to the semi-trailing arm (5) and on the other hand to a vehicle body and is guided through the two upper arms (11, 12).

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