DE102020114437A1 - Wheel suspension for a vehicle rear axle - Google Patents

Abstract

The invention relates to a wheel suspension for the rear axle of a two-track vehicle, in which a wheel carrier (9) for a deflected rear wheel is articulated to a vehicle subframe (1) via a link assembly (11) on opposite sides of the vehicle with reference to a vehicle center longitudinal axis (M) is, wherein the link assembly (11) has a link (17), in particular a tie rod, which is articulated to a wheel carrier-side articulation point (20) on the wheel carrier (9) and to a body-side articulation point (22) on a subframe-side link bracket (21) is articulated, the link (17) being assigned an actuator unit (19) by means of which the spatial position of the pivot point (20) of the link (17) on the wheel carrier side can be adjusted by a travel (Δy). According to the invention, the handlebar bracket (21) of the handlebar (17) is connected to the subframe (1) via a bracket support (23) that is flexible in the transverse direction (y) of the vehicle, and in particular is flexurally elastic.

Description

The invention relates to a wheel suspension for a rear axle of a two-track vehicle according to the preamble of claim 1.

In a wheel suspension for a vehicle rear axle, a wheel carrier for an unguided rear wheel is articulated to a subframe of the vehicle via a link assembly with reference to a vehicle center longitudinal axis on opposite sides of the vehicle. The handlebar assembly has a tie rod for a stable wheel guidance. This is articulated at a pivot point on the wheel carrier on the wheel carrier and articulated on the subframe at a pivot point on the body. In a conventional wheel suspension, the tie rod is implemented as a rigid link that is linked to a link bracket on the subframe side. In the prior art, the handlebar bracket is designed to be extremely dimensionally stable and is connected to the subframe with high connection rigidity. This ensures in the prior art that the forces that arise during driving can be absorbed properly without the wheel carrier-side connection point of the tie rod being shifted and thus the kinematics of the wheel suspension being changed.

In contrast to such a conventional wheel suspension, the toe angle behavior of the wheel suspension can be actively changed in the generic prior art. For this purpose, the tie rod is assigned an actuator unit, which is part of an active chassis. By means of the actuator unit, the spatial position of the articulation point of the tie rod on the wheel carrier side can be adjusted by an adjustment path in order to adjust the toe angle behavior of the wheel suspension as a function of the compression / rebound travel of the vehicle.

From the EP 2 251 217 A1 a rear wheel suspension for a motor vehicle with a tracking device is known. The toe adjustment device has a function of switching between two lane-relevant stiffness states of a vehicle driver provided with elastic bearings. From the DE 10 2009 022 589 A1 a vibration-isolated wheel axle for a motor vehicle is known. The wheel axle has a subframe mounted on the body via damping bushes. In order to change the toe-in of a rear wheel, this is assigned two control arms supported by elastic bushings. From the DE 10 2016 122 067 A1 a wheel suspension for a vehicle wheel is known which has an actuator for setting a wheel track.

The object of the invention is to provide a wheel suspension for a vehicle rear axle in which the behavior of the wheel suspension can be set in a structurally simple manner.

The object is achieved by the features of claim 1. Preferred developments of the invention are disclosed in the subclaims.

According to the characterizing part of claim 1, the body-side handlebar bracket of a handlebar, in particular the tie rod, is no longer rigidly connected to the subframe support, but rather connected to the subframe via a bracket support that is flexible in the transverse direction of the vehicle, in particular flexurally elastic. In the case of a tie rod adjustment, the actuator unit acts with an actuating force on the bracket support, which is flexible in the transverse direction of the vehicle, whereby this, together with the tie rod articulated to it, can be adjusted in the transverse direction of the vehicle to the outside or inside of the vehicle in order to set a toe angle behavior of the wheel suspension.

The following aspects of the invention are explained using the tie rod. However, the invention is not limited to the tie rod alone. Rather, the invention can also be applied to other links, for example a camber link, by means of which a camber gradient can be varied.

In a simple technical implementation, the bracket support can be fastened with its support foot on the subframe, while the link bracket is connected to a free support end spaced from the support foot over a lever arm length. The handlebar bracket can be constructed conventionally, for example from two spaced-apart bracket wings, between which the tie rod is rotatably mounted.

When adjusting the tie rod, the bracket support, which is flexible in the transverse direction of the vehicle, is subjected to bending stresses. The bracket support can be a flat profile bending beam fastened on one side to the subframe, which is designed in the manner of a leaf spring.

The handlebar bracket for the tie rod can be positioned on a flat side of the bracket support on the outside of the vehicle, while the actuator unit acts on a side of the bracket support on the inside of the vehicle.

In view of the limited space available in the rear axle of the vehicle, a package-optimized design of the actuator unit is of great importance. Against this background, the actuator unit can have a linkage, specifically with a lifting element, which can be adjusted in height in the vertical direction of the vehicle via an adjustment stroke, and with an intermediate lever. The intermediate lever is on hinged to a pivot point inside the vehicle on the lifting element and hinged to the flexible console support at a pivot point outside the vehicle.

With a linear stroke of the lifting element in the vertical direction of the vehicle, the intermediate lever is pivoted upwards or downwards about its pivot point on the outside of the vehicle. At the same time, the linear movement of the lifting element is impressed on the intermediate lever pivot point inside the vehicle. In this way, the intermediate lever pivot point on the outside of the vehicle, together with the console support, is shifted by an adjustment path in the transverse direction of the vehicle to the inside of the vehicle or to the outside of the vehicle.

An actuating drive can be assigned to the lifting element, by means of which the lifting element can be adjusted in height. The actuator is part of an active chassis system. With regard to package optimization and with regard to setting accuracy, the setting drive can have a threaded spindle which can be driven by an electric rotary drive motor and which interacts with an adjusting nut connected to the lifting element.

In particular in the case of large-scale production, it is relevant if the actuator unit according to the invention for adjusting the tie rod can be installed in the series vehicle to be produced in a favorable manner in terms of production technology without major conversion measures. Against this background, the actuating drive of the actuator unit can be fastened to the subframe via an actuating drive carrier, in particular via a screw connection. The actuator, the lifting element and the intermediate lever and the handlebar bracket together with the bracket support can be components of a pre-assembly unit. This can preferably be attached to the subframe in a modular design.

When the rotary drive motor is supplied with electrical energy, the threaded spindle rotates, whereby the lifting element - depending on the direction of rotation - is adjusted to the top or bottom of the vehicle. If the rotary drive motor is not supplied with electrical energy, the lifting element remains in its height position, provided the thread engagement between the adjusting nut of the lifting element and the threaded spindle is designed to be self-locking.

The actuating drive of the lifting element can be controlled in different ways. In a first control variant, the lifting element can be adjusted continuously over its linear stroke and can assume any stroke position. In a second control variant, which is simpler in terms of control technology, the lifting element can only move to two or three predefined lifting positions. In particular, when the device is designed on a camber link and no longer on the tie rod, different characteristics can be controlled. In this case, the customer can have his vehicle driven more sportily or more comfortably at the push of a button.

A cost-saving attachment of the pre-assembly unit that takes place with little effort in terms of production technology is of great relevance. In particular, it must be possible to install the pre-assembly unit in a series vehicle without major modifications. Therefore, the pre-assembly unit according to the invention must be able to be attached to an existing vehicle subframe in the vehicle manufacturing plant in a simple manner instead of a conventional, rigidly connected subframe console.

By means of the invention, a tie rod adjustment is made possible in which a discrete switchover of the tie rod, that is, an adjustment from one position to another, is made possible, without intermediate positions or adjustment curves.

An exemplary embodiment of the invention is described below with reference to the accompanying figures.

• 1 in einer perspektivischen Darstellung von oben eine Fahrzeug-Hinterachse eines zweispurigen Fahrzeugs; sowie
• 2 und 3 die Aktoreinheit im eingefahrenen Zustand (2) und im ausgefahrenen Zustand (3).

Show it:

• 1 in a perspective view from above a vehicle rear axle of a two-lane vehicle; as
• 2 and 3 the actuator unit in the retracted state ( 2 ) and when extended ( 3 ).

In the 1 is in a perspective view from above a vehicle rear axle with a subframe 1 shown, the frame-shaped made of side subframe longitudinal members 3 and subframe cross members 5 is constructed, which is the subframe longitudinal member 3 connect with each other. The two subframe longitudinal members 3 are in the vehicle longitudinal direction x to the front of the vehicle and to the rear of the vehicle via the subframe cross member 5 also with side member segments 6th extended. These each have an auxiliary frame bearing at their ends 7th for attachment to a body structure, not shown, of the motor vehicle.

A wheel suspension is assigned to the vehicle rear axle, with reference to a vehicle center longitudinal axis M. ( 1 ) one wheel carrier on each side of the vehicle 9 for a non-steered rear wheel via a multi-link assembly 11th on the subframe 1 is hinged. The multi-link association 11th points in the 1 for example, a total of five spatially distributed, rigid handlebars 13 to 17 on, of which the link 17 acts as a tie rod. The tie rod 17 is in the 1 in the vehicle longitudinal direction x behind an axis of rotation D. of the vehicle rear wheel arranged to be in a Driving operation a swivel movement on the wheel carrier 9 in order to be able to pivot a pivot axis aligned in the vehicle vertical axis z. The tie rod 17, viewed in the vertical direction z of the vehicle, is also approximately at the same height as the axis of rotation D. arranged so that as a result of a compression or rebound movement of the vehicle in addition to the toe angle adjustment, no other movement component is added.

The handlebars 13 to 17 are both on the subframe 1 as well as on the wheel carrier 9 connected to pivot. The link connection can preferably be realized by rubber-metal sleeve bearings.

The essence of the invention relates to the articulation of the tie rod 17 on the subframe 1 . As from the 1 it can be seen, the tie rod 17 is at a pivot point on the wheel carrier side 20th on the wheel carrier 9 hinged and at a pivot point on the body 22nd on the subframe 1 hinged. The tie rod 17 is an actuator unit 19th assigned, which is part of an active chassis. When activating the actuator unit 19th can the tie rod 17 in the vehicle transverse direction y to the inside of the vehicle or to the outside of the vehicle by a slight travel Δy ( 3 ) are adjusted, whereby a toe angle behavior of the wheel suspension can be changed via the compression or rebound movement of the vehicle.

The articulation point on the body is used to implement the tie rod adjustment 22nd the tie rod 17 with a handlebar bracket 21 and a console bracket 23 realized. The handlebar console 21 according to the invention, the tie rod 17 is not rigidly connected to the subframe 1 connected, but rather via the flexible console support 23 on the subframe 1 attached. The console support 23 is in the 2 or 3 than a one-sided on the subframe 1 Tightly clamped flat profile bending beam designed in the manner of a leaf spring. Its carrier foot 25th ( 3 ) is at a screw point 24 on the subframe 1 attached. In addition, the console support 23 one over a lever arm length I. ( 3 ) from the carrier foot 25th spaced free beam end 27 on which the tie rod handlebar console 21 is positioned.

The tie rod handlebar console 21 is in the figures on the flat side of the console support outside the vehicle 23 positioned while on the inside of the vehicle flat side of the console support 23 the actuator unit 19th a force Fs ( 3 ) can exercise.

The following is based on the 2 and 3 the structure and functionality of the actuator unit 19th described: Accordingly, the actuator unit 19th an electric rotary drive motor as the actuator 29 ( 2 ) on. This is via a carrier plate 31 on the rear subframe cross member 5 screwed (screw connections 26th in the 2 ). The rotary drive motor 29 can be a threaded spindle aligned in the vertical direction z of the vehicle 33 drive. This works with a, in a lifting element 33 arranged, not shown adjusting nut together. When the threaded spindle is turned 30th becomes the lifting element 33 by one stroke Δz ( 3 ) height-adjusted.

The lifting element 33 is part of a linkage in which the lifting element 33 in the vehicle transverse direction y on both sides via an intermediate lever 35 ( 2 ) on the respective bracket support 23 is hinged. The intermediate levers 35 are at pivot points on both the lifting element 33 as well as on the respective console support 23 articulated pivotable. In the figures is the rotary drive motor 29 over the carrier plate 31 centered on the rear subframe crossmember 5 positioned.

With a linear stroke Δz ( 3 ) of the lifting element 33 in the vehicle vertical direction z up or down is the intermediate lever 35 pivoted up or down about its pivot point outside the vehicle. At the same time, the vehicle-interior intermediate lever pivot point is the linear movement of the lifting element 33 imprinted. In this way, the intermediate lever pivot point on the outside of the vehicle becomes together with the console support 23 in the vehicle transverse direction y towards the inside or outside of the vehicle by a travel distance Δy postponed. Even with a slight adjustment movement Δy of the toe link 17 is a significant change in the toe angle of the wheel carrier 9 achieved. With the adjusting movement Δy of the toe link 17 is the flexurally elastic bracket support 23 with one force Fs ( 3 ) applied. This leads to a flexurally elastic adjustment of the console support 23 in the transverse direction of the vehicle y towards the inside or outside of the vehicle.

In the 2 is the lifting element 33 shown by way of example in a retracted state in which the lifting element 33 is adjusted to the top of the vehicle. By appropriate electronic control of the rotary drive motor 29 becomes the lifting element 33 by one stroke Δz extended to the bottom of the vehicle, as shown in the 3 is shown. In this case, the flexible bracket support is used 23 a force Fs exercised to the outside of the vehicle, whereby the tie rod 17 to the adjustment path Δy relocated to the outside of the vehicle.

In the figures, the rotary drive motor 29 , the lifting element 33 who have favourited intermediate levers 35 who have favourited Handlebar Consoles 21 including bracket support 23 a pre-assembly module that is modularly attached to the subframe 1 is attachable. An essential aspect of the invention relates to an installation of the pre-assembly module on the subframe that is economical in terms of installation space and simple in terms of production technology 1 . Before this According to the invention, the background is the rotary drive motor 29 , the lifting element 31 who have favourited intermediate levers 35 as well as the handlebar consoles 21 including console supports 23 in a common vehicle transverse plane Y Z arranged, which is spanned between the vehicle transverse direction y and the vehicle vertical direction z, whereby the pre-assembly module is designed to be particularly short in the vehicle longitudinal direction x. In addition, the pre-assembly module is space-saving in an assembly room 37 ( 1 ) positioned between the rear longitudinal member segments 6th and the rear subframe cross member 5 spans.

Furthermore, the screw axis of the screw connections 26th (between the actuator support plate 31 and the rear subframe cross member 5 ) as well as the swivel axes S. of the intermediate lever 35 aligned axially parallel to each other in the vehicle longitudinal direction x, whereby the installation of the pre-assembly module on the subframe 1 further simplified. The console supports 23 are in the 3 not on the rear subframe crossmember 5 , but on the rear longitudinal member segments 6th screwed (screw connections 24 in the 3 ).

List of reference symbols

1

Subframe

3

Subframe side members

5

Subframe cross member

6th

Side member segments

7th

Subframe bearing

9

Wheel carrier

11

Multi-link association

13 to 17

Handlebars

19th

Actuator unit

20th

pivot point on the wheel carrier side

21

Handlebar bracket

22nd

pivot point on the body side

23

Console support

24

Screw connection

25th

Support foot

26th

Screw connection

27

free end of the beam

29

Rotary drive motor

30th

Threaded spindle

31

Actuator carrier

33

Lifting element

35

Intermediate lever

37

Assembly room

Fs

Actuating force

S.

Swivel axis

M.

Vehicle center longitudinal axis

D.

Axis of rotation

I.

Lever arm length

Δy

Travel

Δz

Stroke

Y Z

Vehicle transverse plane

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

Patent literature cited

• EP 2251217 A1 [0004]
• DE 102009022589 A1 [0004]
• DE 102016122067 A1 [0004]

Claims (11)

Wheel suspension for the rear axle of a two-track vehicle, in which, with reference to a vehicle center longitudinal axis (M) on opposite sides of the vehicle, a wheel carrier (9) for a deflected rear wheel is articulated to a vehicle subframe (1) via a linkage (11), the Handlebar assembly (11) has a handlebar (17), in particular a tie rod, which is articulated on a wheel carrier-side articulation point (20) on the wheel carrier (9) and is articulated at a body-side articulation point (22) on a subframe-side handlebar bracket (21), wherein an actuator unit (19) is assigned to the handlebar (17), by means of which the spatial position of the pivot point (20) on the wheel carrier side of the handlebar (17) can be adjusted by an adjustment path (Δy), characterized in that the handlebar bracket (21) of the handlebar ( 17) is connected to the subframe (1) via a bracket support (23) which is flexible in the transverse direction of the vehicle (y) and in particular is flexible and elastic, and that for handlebar adjustment di e actuator unit (19) acts with an actuating force (Fs) on the bracket support (23), which is flexible in the transverse direction of the vehicle (y). Suspension after Claim 1 , characterized in that the bracket support (23) is fastened with its support foot (25) on the subframe (1), and that on its free end of the support (27) spaced from the support foot (25) by a lever arm length (I) the handlebar bracket (21 ) is connected. Suspension after Claim 1 or 2 , characterized in that the bracket support (23) is a flat-profile flexural beam, in particular clamped to one side on the subframe, which is designed in particular in the manner of a leaf spring, and / or that the handlebar bracket (21) is positioned on a side of the bracket support (23) outside the vehicle and the actuator unit (19) acts on a side of the console support (23) inside the vehicle. Wheel suspension according to one of the preceding claims, characterized in that the actuator unit (19) has a linkage, namely with a lifting element (33) which can be adjusted in height in the vertical direction of the vehicle (z) via an adjustment stroke (Δz), and with an intermediate lever ( 35), which is articulated so that it can pivot about pivot axes (S) via pivot points both on the lifting element (33) and on the bracket support (23). Suspension after Claim 4 , characterized in that with a linear stroke (Δz) of the lifting element (33) in the vertical direction of the vehicle (z) the intermediate lever (35) pivots up or down about its pivot point on the outside of the vehicle, and that at the same time the intermediate lever pivot point inside the vehicle, the linear movement of the lifting element ( 33) is imprinted so that the vehicle-external intermediate lever pivot point together with the bracket support (23) in the vehicle transverse direction (y) is moved inside or outside the vehicle by a travel (Δy). Suspension after Claim 4 or 5 , characterized in that the lifting element (33) is height-adjustable with an adjusting drive, and that in particular the adjusting drive has a threaded spindle (30) which can be driven by a rotary drive motor (29) and which interacts with an adjusting nut connected to the lifting element (33). Suspension after Claim 6 , characterized in that the actuating drive can be fastened to the auxiliary frame (1) via an actuating drive carrier (31), in particular in a screw connection (26), and that the actuating drive, the lifting element (33), the intermediate lever (35) and the handlebar bracket ( 21) form a pre-assembly module that can be attached to the subframe (1) in a modular design. Suspension after Claim 6 or 7th , characterized in that the actuating drive, the lifting element (33), the intermediate lever (35) and the link bracket (21) with their bracket support (23) lie in a common vehicle transverse plane (yz), whereby in particular the pre-assembly module in the vehicle longitudinal direction ( x) is short. Wheel suspension according to one of the preceding claims, characterized in that the subframe longitudinal members (3) are extended to the rear of the vehicle beyond the rear subframe cross member (5) with longitudinal member segments (6), and that in particular between the longitudinal member segments (6) and the rear Subframe cross member (5) an assembly space (37) is spanned in which the pre-assembly module is arranged. Wheel suspension according to one of the preceding claims, characterized in that the screw axis (26) of the screw connection (26) between the actuating drive carrier (31) and the subframe (1), in particular its rear subframe cross member (5), and the pivot axes ( S) of the intermediate lever (35) of the actuator unit (19) are aligned axially parallel to one another in the vehicle longitudinal direction (x). Wheel suspension according to one of the preceding claims, characterized in that the screw axis of the screw connection (24) between the bracket support (23) and the subframe (1) is aligned in the vehicle transverse direction (y), and that in particular the bracket support (23) via the Screw connection (24) is connected to the longitudinal member segment (6).

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