The invention relates to a wheel suspension for a motor vehicle and to a wheel-guiding control arm.
Wheel suspensions for motor vehicles are known from the prior art. In this connection reference should be made to DE 10 2013 211 535 A1, which discloses a steerable rear-wheel suspension for a motor vehicle. The wheel suspension described therein comprises, among other things, a wheel-guiding control arm with a longitudinal control arm section and a transverse control arm section, wherein the longitudinal control arm section is provided with a forward bearing on the body side and the transverse control arm section is provided with a rear bearing farther inside in relation thereto on the body side. The essentially L-shaped wheel-guiding control arm so formed can pivot relative to the vehicle body about a rotational axis that extends through the forward body-side bearing and the rear body-side bearing. As can be seen for example in
A purpose of the present invention is to indicate a wheel suspension of the type described to begin with, by virtue of which on the one hand sufficient longitudinal comfort can be obtained and in addition the secondary spring rate is reduced.
The objective is achieved by a wheel suspension having the characteristics specified in the independent claims. According to the invention, a wheel suspension for a vehicle is described, which comprises a wheel carrier fitted so that it can pivot relative to a wheel-guiding control arm, such that the wheel-guiding control arm has a longitudinal control arm section with a forward body-side bearing and a transverse control arm section with a rear body-side bearing, wherein the rear body-side bearing is axially orientated parallel to a rotational axis of the wheel-guiding control arm that extends through the body-side bearings.
To achieve sufficient longitudinal comfort it is generally known to connect longitudinal control arms to the body by means of a rubber bearing so that, for example during a braking process, the longitudinal control arm will have a degree of compliance in the longitudinal direction of the vehicle relative to the vehicle body. To enable such longitudinal compliance, for example in the wheel suspensions known from DE 10 2103 211 535 A1 the transverse section of the wheel-guiding control arm is in the form of a sheet that can bend in the longitudinal direction of the vehicle (also called a “blade”), so that it can deform in the longitudinal direction of the vehicle when the vehicle is braked. Since in addition the longitudinal control arm section is connected to the body by means of a rubber bearing, when the transverse control arm section is deformed, at least the longitudinal control arm section of the wheel-guiding control arm is slightly compliant in the longitudinal direction of the vehicle, and this contributes toward increasing the driving comfort of the vehicle.
According to the invention it was considered advantageous to axially orientate the rear body-side bearing of the transverse control arm section so that it is parallel to the rotational axis that extends through the forward body-side bearing of the longitudinal control arm section and the rear body-side bearing of the transverse control arm section. From the practical standpoint the bearing axis of the rear body-side bearing, in other words in which the bearing offers least resistance against twisting, coincides with the rotational axis of the wheel-guiding control arm. One effect of this arrangement is that the rear body-side bearing, which according to an advantageous further development of the invention is in the form of an elastomer bearing, is stressed only to a small extent during a spring movement of the wheel-guiding control arm so that the secondary spring rate (i.e. the rigidity that opposes a spring movement of the wheel-guiding control arm, disregarding the elastic rigidity of the vehicle body) of the wheel suspension is particularly small. This is because during the spring movement of the wheel-guiding control arm the rear body-side bearing twists about its bearing axis—i.e. with very little resistance and wear. Largely independently of this, the longitudinal comfort of the wheel suspension is advantageously ensured by elastic deformability of the transverse control arm section of the wheel-guiding control arm. Thus, the secondary spring rate can be kept small with no negative influence on the longitudinal comfort.
In a preferred further development of the wheel suspension, the wheel-guiding control arm is essentially L-shaped, in that its longitudinal control arm section forms the longer arm and the transverse control arm section forms the shorter arm of an “L”. It should be pointed out that in this context the expression “essentially L-shaped” can be interpreted broadly, in particular meaning that the longitudinal control arm section and the transverse control arm section are each of a certain length and are connected approximately at right-angles to one another. The longitudinal control arm section or the transverse control arm section do not necessarily have to be straight over their full length but, for example to suit fitting-space requirements, can also deviate from a purely rectilinear shape. Due to the overall approximately L-shaped form of the wheel-guiding control arm it can also be called a trapezoidal control arm.
As already explained, the longitudinal control arm section of the wheel-guiding control arm is provided with a forward bearing on the body side and the transverse control arm section with a rear bearing on the body side. According to a preferred design feature the rear body-side bearing of the wheel-guiding control arm is arranged closer to the middle of the vehicle, in relation to a transverse direction of the vehicle, than is the forward body-side bearing, which in particular produces an arrangement in which the rotational axis of the wheel-guiding control arm is inclined at an angle relative to the longitudinal direction of the vehicle. Thus, from the kinematic standpoint the wheel-guiding control arm is a so-termed “oblique control arm”.
Since at least the rear body-side bearing and preferably also the forward body-side bearing are in the form of elastomer bearings, the wheel suspension provides particularly great driving comfort. In particular the design of the forward body-side bearing as an elastomer bearing enables the wheel-guiding control arm to be at least slightly movable (compliant) in the longitudinal direction of the vehicle relative to the vehicle body. Besides the mechanical elasticity, the use of elastomer bearings advantageously enables an acoustic decoupling of the wheel-guiding control arm relative to the axle carrier or the vehicle body.
The wheel-guiding control arm can be connected to the vehicle body in various ways. A preferred further development of the invention provides that the wheel-guiding control arm is connected via the rear body-side bearing to an axle carrier and via the forward body-side bearing to the vehicle body. Alternatively, the forward body-side bearing could also be connected to the axle carrier, whereby the fitting of the wheel suspension as a complete assembly to the vehicle body can be simplified. On the other hand, a connection of the forward body-side bearing directly to the vehicle body has the advantage that the axle carrier can be made smaller, so that it may be possible to use already existing connection points to the vehicle body. A further conceivable alternative is to connect both the rear body-side bearing and also the forward body-side bearing directly to the vehicle body.
To achieve sufficient longitudinal comfort of the wheel suspension, it is advantageously provided that the transverse control arm section of the wheel-guiding control arm has a substantially greater elasticity in relation to the driving direction than in the vertical or transverse directions of the vehicle. In particular this can be achieved by making the transverse control arm section of the wheel-guiding control arm in the form of a metal sheet that can bend in the longitudinal direction of the vehicle (also called a “blade”).
As a general design feature of the wheel suspension, the wheel carrier is generally mounted so that it can pivot relative to the wheel-guiding control arm. A preferred further development of the wheel suspension provides that the wheel carrier is connected to the wheel-guiding control arm in a first connection area directly, in particular by a ball joint, and in a second connection area indirectly via an integral joint. Thus, the wheel carrier and the wheel-guiding control arm are connected to one another in two connection areas such that in the first connection area the connection is direct and in the second connection area the connection is indirect. For example, in the first connection area a ball joint or a rubber mounting could be used, whereby three rotational degrees of freedom can be realized between the wheel carrier and the wheel-guiding control arm. In the second connection area an integral joint is used, this being in particular a link component, for example a two-point link one end of which is connected by a hinge to the wheel carrier and the other end via a hinge to the wheel-guiding control arm. With an appropriate design and arrangement of the connection areas the effect can be produced that the wheel carrier can pivot about an imaginary pivoting axis relative to the wheel-guiding control arm.
Expediently, the two connection areas are in this case a distance apart in the longitudinal direction of the vehicle, preferably with one of the areas in front of the middle of the wheel and the other behind the middle of the wheel. In that way a sufficiently large distance between the first and second connection areas can be provided, whereby the supporting forces acting upon the integral joint can be reduced.
The wheel suspension can be made particularly compact if, in the undeflected state of the wheel carrier, the integral joint extends essentially in the vertical direction of the vehicle. Furthermore, this enables an approximately equally sized maximum positive or negative steering angle to be produced.
To achieve the smallest possible secondary spring rate of the wheel suspension, according to an advantageous further development the axes of the link of the integral joint, as the wheel suspension is viewed from above, are orientated approximately parallel to the rotational axis of the wheel-guiding control arm.
Also in order to reduce the secondary spring rate, according to another advantageous design of the wheel suspension the axes of the hinge of the integral joint, when the wheel suspension is viewed from the side, are orientated so that they intersect at a point forward of the middle of the wheel in relation to the longitudinal direction of the vehicle, so that the axis of the joint-side hinge of the integral joint, when the wheel suspension is viewed from the side, is orientated preferably approximately parallel to the rotational axis of the wheel-guiding control arm.
The result of the orientation described for the hinge axes of the integral joint is that the mountings of the integral joint, preferably elastomer mountings, are hardly stressed at all in a cardanic manner, and this too contributes toward reducing the secondary spring rate of the wheel suspension. In addition this also prolongs the useful life of the elastomer mountings. Moreover, thanks to the lower secondary spring rate the vehicle can be better controlled.
Expediently, the wheel carrier is also connected to an axle carrier and/or the body by way of a camber link, such that the camber link is associated with an upper link plane and the wheel-guiding control arm with a link plane lower down. In that way the wheel suspension as a whole can be made more compact.
To steer the wheel carrier about a steering axis, it is advantageous for steering means to be associated with the wheel suspension, which is advantageously connected to the wheel carrier behind the middle of the wheel. Basically, this can be steering means of various types.
According to a preferred further development of the wheel suspension the steering means are in the form of a track control link which for active steering can be actuated by an actor. The actuation by means of an actor then brings about in particular a translation movement of the track control link in the transverse direction of the vehicle, in order to produce by means of the movement of the track control link a steering movement of the wheel carrier and the wheel fitted onto it.
Alternatively, it is conceivable for the steering means to be a track rod for passive steering by way of the wheel stroke. In this way the wheel suspension can be designed particularly inexpensively.
The wheel suspension can be made particularly compactly if the steering means are connected, in particular directly, to the wheel carrier. In that way, by virtue of a direct engagement of the steering means with the wheel carrier, particularly precise steering of the wheel carrier about its steering axis can take place. In this case the steering means are advantageously arranged behind the middle of the wheel, whereby sufficient structural space for driving the wheels is provided. Alternatively the steering means can co-operate indirectly with the wheel carrier, for example if the steering means are connected to the integral joint.
Since the transverse control arm section of the wheel-guiding control arm is preferably positioned behind the middle of the wheel, sufficient structural space for possible drive means can be provided in the area of the middle of the wheel. Advantageously, the longitudinal control arm section of the wheel-guiding control arm extends as far as in front of the middle of the wheel. By virtue of the longitudinal control arm section, in particular braking torques and acceleration torques or forces that occur can be supported.
Besides the wheel suspension described, the invention also relates to a wheel-guiding control arm according to the characteristics specified in the independent claims. This wheel-guiding control arm is particularly suitable for mounting a wheel carrier of a wheel suspension as described earlier. The wheel-guiding control arm according to the invention has a longitudinal control arm section and a transverse control arm section, each with a bearing at its end, and is characterized in that the bearings at the ends are orientated parallel to a rotational axis that extends through the bearings. To avoid repetition, for the other advantageous features of the wheel-guiding control arm reference should be made to the rest of the description.
Below, the invention is explained in greater detail with reference to an example embodiment illustrated in the drawings, from which further advantageous effects of the invention emerge. The drawings below show:
The wheel suspension 1 shown comprises a wheel carrier 3 mounted so that it can pivot relative to a wheel-guiding control arm 4. The wheel-guiding control arm 4 is an essentially L-shaped component comprising a longitudinal control arm section 4a and a transverse control arm section 4b. In this connection reference should be made to
As can also be seen in
Referring again to
As can be seen in
In the example embodiment described here the wheel-guiding control arm 4 is connected to the axle carrier 2 by the rear body-side bearing 12, whereas the forward body-side bearing 11 is connected directly to the vehicle body (not shown). According to a conceivable alternative design, the axle carrier 2 could also be designed such that the forward body-side bearing 11 too is connected to the axle carrier. The kinematics of the mounting of the wheel-guiding control arm 4 would not be influenced by this.
As already mentioned in connection with
As already mentioned earlier, the wheel carrier 3 is mounted so that it can pivot relative to the wheel-guiding control arm 4. For that purpose, in the example embodiment of the wheel suspension 1 illustrated, the wheel carrier 3 is connected to the wheel-guiding control arm 4 at two connection areas, so that the wheel carrier 3 can pivot about an imaginary pivoting axis relative to the wheel-guiding control arm 4. An imaginary connection line between a hinge holder 19 and a hinge 14 of a camber link on the wheel carrier side in this case represents the imaginary pivoting axis of the wheel carrier 3.
As already mentioned in connection with
From
According to the representation shown in
The two (first and second) connection areas where the wheel carrier is connected to the wheel-guiding control arm are a distance apart from one another in the longitudinal direction x of the vehicle, as can be seen in
As can be seen most clearly in
The described indirect and direct coupling of the wheel carrier to the wheel-guiding control arm 4, together with the connection by way of the camber link 8, enable the wheel carrier 3 to pivot relative to the wheel-guiding control arm 4 about a virtual steering axis that passes through the points 19 and 14. When such a steering movement takes place the integral link 5 pivots about the axis 22 of the control-arm-side hinge 16, and to control this steering movement of the wheel suspension 1 steering means 9 are provided. In the example embodiment shown these means consist of a track control link 9 which, for active steering, can be actuated by an actor (not illustrated further). The track control link 9 is a two-point link component, which at its end on the outside of the vehicle is articulated by way of a track hinge 17 positioned behind the wheel center 23. Alternatively, in accordance with a different design (not shown here) the track control link 9 could engage directly with the integral link 5 a distance away from its hinge 16 on the control-arm side.
As can be seen from
Number | Date | Country | Kind |
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10 2016 200 095.0 | Jan 2016 | DE | national |
This application is a National Stage completion of PCT/EP2016/080214 filed Dec. 8, 2016, which claims priority from German patent application serial no. 10 2016 200 095.0 filed Jan. 7, 2016.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2016/080214 | 12/8/2016 | WO | 00 |