DE102011077751A1 - Wheel suspension device for steerable rear wheel of two-track vehicle, has pivot bearing that is connected via track rod joint to actuating element for both rear wheels of vehicle - Google Patents

Abstract

The suspension device has a pivot bearing (2) that is provided over joints when viewed in the vehicle longitudinal direction located at different height joints (6) so as to connect trailing arm (1) with bearings or joints. The longitudinal arms (21,22) are attached with steering axis of wheel (20). A tie rod (8) is articulated with pivot bearing. The pivot bearing is connected via a track rod joint (10) to an actuating element (9) for both rear wheels of the vehicle. An actuator is located in plan view approaching instantaneous axis (11) of the suspension portion.

Description

The invention relates to an independent suspension of an at least slightly steerable by means of an actuator rear wheel of a two-lane vehicle, the wheel bearing pivot bearing by extending substantially in the vehicle longitudinal direction trailing arm and two extending predominantly in the vehicle transverse direction and when viewed in the vehicle longitudinal direction in lying at different levels and not cutting in this view wishbone is guided, the opposite ends of the pivot bearing are at least slightly articulated directly or indirectly connected to the vehicle body. The state of the art is in addition to the DE 41 29 643 C2 especially on the DE 38 27 039 A1 directed.

In the first-mentioned document, an example of what is also known in the art as a so-called central link axle is described, which is characterized in particular by driven wheels by a favorable kinematic behavior and is more advantageous than the known so-called oblique link axles. In the second-mentioned document, a way is shown how such a guided wheel can be slightly steered. In this case, the toe angle of this wheel is adjustable by means of an actuator on the vehicle body-side bearing of the trailing arm suitable attacking. This known arrangement requires not only in the area of the vehicle body-side trailing arm bearing but also in the vicinity of the trailing arm for its horizontal pivoting (in the vehicle transverse direction) additional space, which may not be available depending on the design of the vehicle body in this area , Furthermore, it is disadvantageous that two actuators for steering the two rear wheels are required on a two-lane vehicle, which is not only expensive, but also difficult to represent control technology.

In the present case, an improved in this respect independent suspension or vehicle axle with the features listed in the preamble of claim 1 while maintaining their advantageous basic kinematic and elastokinematischen properties and essential dimensions are shown (= object of the present invention).

The solution to this problem is characterized in that the pivot bearing is connected in such a way articulated to the trailing arm via two bearings or joints lying at different heights when viewed in the vehicle longitudinal direction, that these bearings or joints describe a predominantly vertically extending steering axis of rotation for the wheel, and in that each wishbone is fastened to the trailing arm via a rubber bearing or a joint having at least a low degree of freedom of rotation, wherein a tie rod is articulated to the pivot bearing, which has a tie rod joint with an actuator of the substantially centrally arranged and effective for both rear wheels of the vehicle actuator is connected, which is at least approximately on or very close to the instantaneous axis of the suspension at least in plan view (ie in a direction perpendicular to the roadway projection). Advantageous developments are content of the dependent claims.

According to the invention is different from the aforementioned DE 38 27 039 A1 one of the joints of the control arm independent steering axis formed and it is created so created additional degree of freedom by a tie rod which engages the wheel, which is now called a pivot bearing but functionally nothing more than a steering axis formed about this pivotable wheel carrier. The now added tie rod of the first rear wheel of the vehicle is connected to an actuator of a further so-called. Also steering actuator and also the other second rear wheel of the vehicle via the tie rod is also connected to an actuating element of the same (steering) actuation. In this actuator or possibly two actuators of the present invention and provided for both rear wheels substantially centrally located actuator may be, for example, a displaceable in the vehicle transverse direction bar, similar to a rack in the front-wheel steering of a car act.

There should be a steering movement or rotational movement of each rear wheel about the steering axis of rotation primarily by an actuator initiated by the said shift of the wheel associated track rod, but not due to substantially vertical compression or rebound movements of the respective wheel relative to the vehicle body, which in any case are of influence or can be, if the actuator is at least in comparison with the wheels mounted relatively rigidly on the vehicle body. Namely, since a central steering actuator effective for both rear wheels of the vehicle is provided, it can not be arranged to follow a compression or rebounding movement of the respective wheel; Rather, such a central steering actuator is attached either directly to the vehicle underbody or to a rear axle. But then could change from a jounce or rebound movement of a wheel through their ultimately fixed to the actuator track rod a toe angle change for this wheel, which is of course not desired.

As a remedy for this problem mentioned is to arrange the hinge point in which the tie rod to the actuator or the actuator of the same, near the so-called. Momentanachse the suspension to which the suspension or its wishbone during compression or rebound of the Move or move the wheel relative to the vehicle body. This instantaneous axis is in a momentary consideration that axis about which the wheel or the wheel center is pivoted during compression or rebounding, but this instantaneous axis is not stationary, but is slightly displaced over a jounce or rebound movement of the wheel. Geometrically, this instantaneous axis represents the cutting line of the upper and lower wishbone plane, each transverse link plane being defined by the longitudinal axis of the respective transverse link extending through the two pivot centers of the respective transverse link and the center of the articulation point of said trailing link on the vehicle ,

In the independent claim is now given that the one hinge point in which the tie rod with the actuator or the actuator is connected to the same (= "tie rod joint") at least in plan view, d. H. lying in a direction perpendicular to the roadway projection at least approximately or very close to the running through the virtual intersection of the two control arms and the pivot point of the trailing arm on the vehicle body instantaneous axis of the suspension. It has been recognized that even hereby an acceptable stability or constancy of the toe angle can be achieved in a compression or rebound movement of the wheel, although it is of course even cheaper if the tie rod joint also considered in the vertical direction (ie in side view or in a view in the direction of travel of the vehicle) is at least approximately at or very close to said instantaneous axis of the suspension (= claim 2). For both views or projections or for both claims is true that the said pivot point of the tie rod can of course only in a certain actuating position of the steering actuator, for example, directly on the said instantaneous axis (for example, on that of the wheel in construction position) where appropriate as such actuator-actuating position that of the neutral position ("center position" without imprinting a present in addition to the wheel basic setting wheel toe angle) of the steering actuator is selected.

Not only because of the displacement of the tie rod joint by the (steering) actuator but also due to displacement of the instantaneous axis in conjunction with a jounce or rebound motion of the wheel of course, this tie rod joint under all circumstances, at least approximately on the said instantaneous axis lie; However, it is recommended that this condition is met in the so-called "design situation" of the wheel. The term "at least approximately" is intended to clarify that the center of said tie rod joint should be very close to the instantaneous axis. "Very close" means that this joint center should, for example, be no further than the 0.1-fold measure of the distance measured on the instantaneous axis between its vertical projection on the instantaneous axis and the center of the articulation point of the trailing arm on the vehicle from the instantaneous axis , The term "constructive position" should be well known and commonplace; This is the position of the wheel, which occupies this at target height level with respect to the vehicle body and in the neutral position of the steering actuator.

In principle, the tie rod can be articulated in the vicinity of the wheel center on the pivot bearing or wheel carrier, but could thus collision problems with other components, such as a spring-damper unit, supported by the vehicle body proportionally to the suspension is, surrendered. Therefore, in view of a space-optimized arrangement of a the steering axis describing bearing or joints bearing and lying substantially within the wheel of the wheel pivot bearing section protrude a toggle both in the vehicle transverse direction and in the direction of travel forward over the wheel bowl out to which the tie rod is articulated with its said tie rod joint opposite end.

An advantageous design of the trailing arm of a suspension according to the invention, on which both the steering axis forming joints and the wheel-side joints of the control arm are attached, is finally specified in claim 4.

In the following the invention will be further explained with reference to an embodiment, wherein the attached 1 almost the top view and thus a vertical projection on the roadway of a suspension according to the invention without drive shaft for the illustrated rear wheel of the two-lane vehicle shows, with the hatched elements shown in the corresponding section. 2 shows a view in the direction of travel from behind with a drive shaft, while in 3 a side view (viewed in the vehicle transverse direction) substantially only the trailing arm with a spring-damper unit attached thereto and the end portion of a toggle lever, which is part of the pivot bearing, not shown in this figure, is shown.

With the reference number 1 is a trailing arm referred to, along with two wishbones 21 and 22 the wheel 20 opposite the vehicle body, not shown, which in the usual way a wheel disc 20a or the like. Has a rim 20b carries on which a tire 20c is raised. About the wheel disc 20a is this wheel 20 together with a brake disc 23 on a wheel hub 4 fastened over a wheel bearing 3 in a pivot bearing 2 , which also as a wheel carrier 2 can be designated, is rotatably mounted. evidenced 2 can this wheel hub 4 from a drive shaft 24 driven, that are offset in rotation about the wheel rotation axis.

The extending substantially in the vehicle longitudinal direction trailing arm 1 is with its front end in a pivot point 12 hinged so articulated on the vehicle body, not shown, that jounce and rebound movements of the wheel 20 be enabled in the vertical direction and low desired changes to the track on the wheel 20 under influence of on the wheel 20 acting lateral forces and / or longitudinal forces.

In his wheel-side end is on the trailing arm 1 an angled baffle structure 1a provided, which extends so far in the vertical direction that on this baffle structure 1a two bearings or joints 6 . 7 above and below the center of the wheel M are fixed, which determine a still further explained steering axis of rotation S, and at the continue on tabs 1b coming from the baffle structure 1a are worked out, including the wheel-side joints 21a . 22a the two wishbones 21 . 22 are fastened above or below the wheel center M. These two wishbones 21 . 22 Although they extend predominantly in the vehicle transverse direction, they are slightly inclined forward when viewed in plan view. As usual in the case of central link axles, the two transverse links overlap in plan view 21 . 22 nearly. As usual with central link axles are the two wishbones 21 . 22 when viewed in the vehicle longitudinal direction (see. 2 ) in different levels and thereby above (wishbone 21 ) or below (wishbone 22 ) of the wheel center M, wherein the wishbone 21 . 22 extend only so far to the vehicle center that they do not intersect, but in the present case only in the view of 2 whose over the wishbones 21 . 22 also extended handlebar axles 21 * . 22 * passing through the two end wishbone hinges.

In the 1 . 3 is the instantaneous axis 11 This suspension is registered by the position of the two wishbones 21 . 22 and the trailing arm 1 is determined. As you know, this instantaneous axis arises 11 to the the wheel 20 is pivoted against the vehicle body during compression or rebound, as a straight line of the handlebars levels of the two wishbones 21 . 22 which, in each case by the respective handlebar axis 21 * respectively. 22 * and the pivot point 12 of the trailing arm 1 are defined.

At the beginning of the previous paragraph were already briefly two joints 6 . 7 , in place of which also suitable rubber bearings or the like. May be provided, mentioned, on the one hand to the support plate structure 1a and thus on the trailing arm 1 are attached. On the other hand, each of these two joints 6 . 7 namely, the joint lying above the center of the wheel M. 6 and the approximately in the vertical direction below this and below the Radmitte M lying joint 7 at the pivot bearing 2 attached. So describe these two joints 6 . 7 a steering axis of rotation S, around which the pivot bearing 2 opposite the trailing arm 1 at least slightly pivotable. This steering axis of rotation S runs predominantly in the vertical direction, but can in the vehicle transverse direction (see. 2 ) and / or in vehicle longitudinal direction (like 3 shows) to be slightly inclined to specifically represent steering-related axis parameters, such as caster / delay line, caster / lead angle, steering roller radius, Störkrafthebelarm by appropriate inclination.

Of course, the additional degree of freedom of this wheel suspension created by the steering axis of rotation S relative to a conventional central link axis must be bound, for which purpose a tie rod 8th is provided, the present one hand to a rigid on the pivot bearing 2 attached and thus virtually a part of the same forming track lever 13 and at the other end to an actuator 9 a steering actuator not shown, also called actuator, is hinged, with which the wheel 20 directed by suitable control, ie a desired toe angle of the wheel 20 can be adjusted. For this purpose, the actuator 9 in vehicle transverse direction according to arrow 26 in 1 relocated.

In this case, the actuator, not shown, is substantially centrally between the two rear wheels 20 arranged for the vehicle and can for example for both wheels 20 the vehicle or its rear axle effective control element 9 envelop in sections.

As can be seen, the so-called. Tie rod joint 10 over which the tie rod 8th with the actuator actuator displaceable by the said actuator in the vehicle transverse direction 9 is connected, at least in the figuratively illustrated construction position of the wheel 20 in plan view (according to 1 ) very close to said momentary axis 11 and in side view ( 3 ) even looks at this, with the front of the figure description explained advantages or consequences. It is in 1 in addition to the center 10 of the tie rod joint 10 the vertical projection 10 ' this joint center 10 on the momentary axis 11 shown. The distance between the points 10 and 10 ' should not be appreciably larger than 0.1 times the distance between the points 10 ' and 12 on the instant axis 11 to meet the said criterion of "very close lying".

Especially for reasons of space is the toggle lever 13 as shown figuratively and shaped described above, namely from the wheel RS of the wheel 20 protruding while the pivot bearing 2 completely within the rim 20b defined Radschüssel RS is located. This also results in no collision with the illustrated spring-damper unit 25 , about which the vehicle body proportionally to the trailing arm 1 is supported, it should be noted that quite a variety of details may be designed differently from the described embodiment, without departing from the content of the claims.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 4129643 C2 [0001]
• DE 3827039 A1 [0001, 0005]

Claims (4)

Independent suspension of an at least slightly steerable by means of an actuator rear wheel of a two-lane vehicle, the wheel ( 20 ) bearing pivot bearing ( 2 ) by a substantially in the vehicle longitudinal direction extending trailing arm ( 1 ) and two wishbones extending predominantly in the vehicle transverse direction and lying in different planes when viewed in the vehicle longitudinal direction and not cutting in this view ( 21 . 22 ) is guided, whose the pivot bearing ( 2 ) opposite ends are at least slightly articulated directly or indirectly connected to the vehicle body, characterized in that the pivot bearing ( 2 ) over two bearings or joints (as viewed in vehicle longitudinal direction at different levels) ( 6 . 7 ) so articulated with the trailing arm ( 1 ), that these bearings or joints ( 6 . 7 ) a predominantly perpendicular steering axis of rotation (S) for the wheel ( 20 ), and that each control arm ( 21 . 22 ) via a rubber bearing or at least a low rotational degree of freedom having joint ( 21a . 22a ) on the trailing arm ( 1 ), wherein further at the pivot bearing ( 2 ) a tie rod ( 8th ) which is articulated via a tie rod joint ( 10 ) with an actuating element ( 9 ) is connected to the substantially centrally arranged and effective for both rear wheels of the vehicle actuator which at least approximately in plan view (ie in a direction perpendicular to the roadway projection) at least approximately or very close to the instantaneous axis ( 11 ) of the suspension is located. Independent wheel suspension according to claim 1, characterized in that the tie rod joint ( 10 ) also viewed in the vertical direction at least approximately on or very close to said instantaneous axis ( 11 ) of the suspension is located. Independent wheel suspension according to claim 1 or 2, characterized in that of a the steering axis of rotation (S) descriptive bearing or joints ( 6 . 7 ) and essentially within the wheel disc (RS) of the wheel ( 20 ) lying portion of the pivot bearing ( 2 ) a track lever ( 13 ) protrudes in the vehicle transverse direction as well as in the direction of travel forward beyond the wheel disc (RS) on which the tie rod ( 8th ) with her said tie rod joint ( 10 ) is hinged opposite end. Independent wheel suspension according to one of the preceding claims, characterized in that in the wheel-side end region of the trailing arm ( 1 ) a hitherto extending in vertical direction baffle structure ( 1a ) is provided that at this not only the two the steering axis of rotation (S) descriptive bearing or joints ( 6 . 7 ) above and below the wheel center (M), but via tabs ( 1b ) for receiving joints ( 21a . 22a ) also the two wishbones ( 21 . 22 ) above and below the wheel center (M) are attached.

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