The invention relates to an independent wheel suspension for powered rear axles of motor vehicles, having a wheel carrier with an upper and lower linkage formed by individual links wherein, with respect to the forward driving direction of the vehicle, the lower linkage has a rear transverse link, as the spring link carrying the spring damper and/or the shock absorber, and a front longitudinal link extending diagonally toward the front inside, as the compression strut; and the upper linkage is formed by a rear transverse link, as the camber strut, and a longitudinal link extending toward the front, as the tension strut. The linking points of these struts to the wheel carrier are offset and toward the inside, with respect to the longitudinal plane of the wheel center. A tie rod is provided which extends in transverse direction of the vehicle and is offset with respect to the transverse plane of the wheel center.
Wheel suspensions of the above-described type are known from German Patent No. DE-PS 30 48 794. They have also proven themselves in practice and distinguish themselves in that, while having a small overall size, they ensure an extremely precise wheel guidance and, at the same time, a good comfort behavior of the axle.
The invention is based on the object of developing such wheel suspensions without any loss of comfort with respect to high axle stiffness with a small overall size, as required particularly for use in heavy passenger cars.
In the case of the wheel suspension of the initially mentioned type, this is achieved in that the tension strut and the camber strut of the upper linkage cross one another in the wheel side area in such a manner that the linking point of the camber strut at the wheel carrier is located in front of the corresponding linking point of the tension strut on the wheel side, and both linking points are located on different sides of the transverse plane of the wheel center. Also in plan view, the camber strut and the spring link as well as the tension strut and the compression strut extend approximately in parallel. The angle between the tension strut and the camber strut of the upper linkage is open toward the vehicle center, in plan view, and is located inside the angle between the compression strut and the spring link of the lower linkage.
By the crossed arrangement of the two struts of the upper linkage, a stiffening of the whole linkage system is obtained. Thus, not only the upper linkage is stiffened, but the crossing of these struts also has the result that the struts of the lower linkage, with respect to the upper linkage, with their linking points on the wheel carrier side, are disposed in a crossed position with respect to the transverse plane of the wheel center. This, while the construction is narrow, it still results in high stability with respect to the alignment of the wheel carrier because swivel movements of the wheel carrier are counteracted by the crossed arrangement of the struts and the crossed bearings of the linking points on the wheel carrier side and by corresponding bracings. The increased axle stiffness has an advantageous effect with respect to a precise wheel guidance during starting and braking. In addition, lateral forces can also be absorbed well. All these effects are achieved without any additional space requirements, and with respect to the same axle stiffnesses, a wheel suspension constructed according to the invention may be even narrower than previously known systems.
The crossed struts forming the upper linkage, in the crossing area, may be guided freely past one another, or one of the struts, if the other strut has a corresponding recess, may be guided through the other strut. Finally, it is even possible to connect the struts elastically in the crossing area, thus, for example, by a rubber link joint of the like, whereby the stiffness of the linkage system can be further improved.
Wheel suspensions having crossed struts are known (Japanese Patent No. 59/223507). In this known wheel suspension, the steered front wheels of a motor vehicle have an upper and a lower linkage for a wheel carrier. One of the linkages is formed by a wishbone, while the other linkage consists of two crossed struts. Since it is known that, in the case of linkages constructed of individual links, the respective imaginary intersecting point of the struts forms an imaginary linking point, in this known construction, the steering axle, with respect to its position, on the one side, is determined by the imaginary point of intersection and, on the other side, by the linking point of the wishbone. By using crossed struts for a linkage, particularly for the upper linkage, certain constructive liberties are therefore obtained with respect to the position of the steering axle which is significant for front wheel suspensions, but plays no particular role in the case of rear wheel suspensions. The known construction has no significant influence on the stability because the second linkage is formed only by a wishbone having a linking point on the wheel carrier side.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.