WO2017137186A1

WO2017137186A1 - Steerable twist-beam rear suspension

Info

Publication number: WO2017137186A1
Application number: PCT/EP2017/050296
Authority: WO
Inventors: Benjamin Bäumer; Knut Heidsieck
Original assignee: Zf Friedrichshafen Ag
Priority date: 2016-02-10
Filing date: 2017-01-09
Publication date: 2017-08-17
Also published as: DE102016201992A1

Abstract

The invention relates to a steerable twist-beam rear suspension (1) for a motor vehicle comprising a twistable cross-beam (4, 43) having a respective trailing arm (2, 3) on both ends thereof, wherein a wheel suspension (8a, 10a) is connected to each trailing arm (2, 3), each mounted on the respective trailing arm such that they can pivot about a steering axis (7, 9), wherein the wheel suspension has a wheel bearing (8, 10) and a steering means (5, 6) connected to same in the longitudinal direction of the vehicle. In addition, each wheel suspension (8a, 10a) is connected to the respective trailing arm (2, 3) via at least two bearings (11, 12, 13), preferably elastomeric bearings, wherein at least one bearing (11, 12, 13) has a stiffness in the longitudinal direction of the vehicle that is different, preferably reduced, at least in comparison to the vertical direction of vehicle.

Description

Steerable torsion beam axle

The invention relates to a steerable beam axle for a motor vehicle with a twistable cross member, which at its two ends in each case one

Trailing arm, wherein with each trailing arm, a suspension is connected, which is mounted in each case about a steering axis pivotally mounted on the respective trailing arm, wherein the suspension is a wheel and a in

Has vehicle longitudinal direction of the wheel carrier subsequent handlebar.

On small and middle-class vehicles with front-wheel drive, mainly composite beam axles are used as the rear axle. It is a cost-effective and space-saving design that is easy to mount on the vehicle.

A rigid, but torsionally soft design of the cross member ensures that a mutual entanglement of the wheel carrier receiving trailing arm is defined allows. Incidentally, the torsionally soft cross member assumes the function of a roll stabilizer with which a high roll stability, ie a desired inclination of the vehicle body when cornering, can be achieved. Other advantages of the joint handlebar axle are a good straight-ahead and a slight toe-in changes during compression and rebound of the axle. For non-steerable

Twist-beam axles are the wheel carrier rigidly connected to the trailing arms, for example, welded.

Under the main aspect, to improve the driving stability, motor vehicles are provided with active rear wheel steering, with which but also the maneuverability of the motor vehicle can be increased. Here, the rear-wheel steering, based on the front-wheel steering with the same or gegensinnigem steering angle can be actuated.

From WO 2013/037652 A1 is a steerable torsion beam axle for a

Motor vehicle known. The steerable torsion beam axle has two trailing arms arranged at a distance from each other, one each with a steering lever provided wheel carrier is arranged pivotably about a respective steering axis. An actuator is attached to one of the trailing arms and engages over

Actuator to a center of the tie rod provided joint. In this area, the tie rod is designed as a pendulum support

Coupling arrangement connected to the cross member. With the trailing arms flange-like links are formed together with which in turn upper and lower bearing elements are screwed to guide a steering knuckle.

From the publication Bernd Heißing, Metin Ersoy, Stefan Gies,

A torsion beam axle with a decoupled wheel carrier is known from "Fahrwerkhandbuch" 3rd, revised and expanded edition 2011, pages 427 and 428. This non-steerable torsion beam axle, which is described on page 428 in Figure 4-27 as "Multi Compliance Twist Beam Axis", is to be replaced by three the steering wheel and the trailing arm arranged hinge points with rubber bearings the self-steering behavior can be improved. This arrangement causes the corresponding wheel carrier to be subject to both longitudinal and lateral forces, e.g. when braking, can go into toe.

An object of the invention is to develop a steerable twist beam axle in such a way that the ride comfort is improved.

This object is achieved by the features of the characterizing part of

independent claim 1 solved. Advantageous embodiments are specified in particular in the dependent claims.

A steerable torsion beam axle according to the invention for a motor vehicle with a twistable cross member has provided at both ends

Trailing arm, wherein with each of the trailing arm, a suspension is connected, which is mounted in each case about a longitudinal axis pivotally mounted on the respective trailing arm. The suspension has a wheel and a in

Vehicle longitudinal direction of this subsequent link on. The suspension of the wheel carrier and handlebar is preferably formed in one piece. Preferably, the steerable beam axle has an at least indirectly with the

Cross member connected actuator, which pivotable by means of tie rods the wheel carrier serves around the steering axles. The actuator acts in other words on the coupling links tie rods on the wheel.

In the case of the steerable torsion beam axle, each wheel suspension is articulated to the trailing arm via at least two bearings, preferably elastomer bearings, so that the steering axle, for example in the vehicle vertical direction, runs through the two bearings.

At least one bearing has in the vehicle longitudinal direction at least in comparison to the vehicle vertical direction different, preferably lower, stiffness. In the vehicle longitudinal direction, the at least one bearing may preferably be softer than in the vehicle vertical direction. This results in an advantageous manner a defined compliance in the vehicle longitudinal direction, said connection of the respective arm to the trailing arm in the vertical direction should be relatively stiff.

In a further embodiment, at least one bearing should be designed as a sleeve bearing. It is further provided that the sleeve bearing in at least one, substantially horizontally emanating from the trailing arm, preferably in

Vehicle vertical direction projecting, receiving lug is received and the suspension has at least two each of the bearings, preferably an outer sleeve of the sleeve bearing, receiving support arms. Between the outer sleeve and an inner sleeve is an elastic, preferably made of a rubber, composite element arranged with respect to the axial stiffness higher radial stiffness. In this case, the inner sleeve is positively connected to the receiving lugs, preferably screwed by aligned by one another

Holes of the receiving lugs each receiving the inner sleeve

Screw runs. The outer sleeve is at its two end faces to the

Receiving lugs spaced so that they can perform against these movements in the longitudinal direction. The outer sleeves can be integrally formed with the support arms. Alternatively, the outer sleeves may be pressed into hollow cylindrical receptacles of the support arms, so that the

Elastomeric bearings are generally easy to assemble and can be exchanged.

In addition, the actuator may preferably be arranged centrally on the transverse profile. The actuator is directly connected to two tie rods, so this can be moved linearly in the vehicle transverse direction. The actuator can be designed as an electric motor with a gear, so that a spindle nut with a motor moves a linearly displaceable spindle. This results in a double-acting actuator, which is articulated directly to each of the tie rods. This allows both suspensions simultaneously and

be moved equally and it is avoided that for the transmission of power from the actuator to the tie rods further movably arranged

Coupling elements in the form of levers, handlebars or the like must be used. For a direct and high positioning accuracy is achieved as possible, which is subject to lower tolerances due to the small number of components.

The actuator can in the case of a hydraulic actuation with a

Have hydraulic cylinder housing provided, wherein in the hydraulic cylinder, a double-acting piston provided with two piston rods is arranged. The two tie rods are each articulated at the end of one of the piston rods.

A further advantageous embodiment provides that the cross member is formed by a along its longitudinal extent inwardly formed tube and at least partially in cross-section U-shaped, wherein the actuator is attached via at least one fastening unit to the cross member having a shaped profile section of the cross member encloses and has a shape that is adapted to a shape of the deformed profile section. By this type of attachment of the actuator to the cross member, the properties, in particular torsional properties, of the cross member are largely unaffected.

Due to the partially U-shaped configuration of the cross section of the cross member, which leads to a double wall of the profile, the torsional properties of the cross member are improved without reducing its required bending stiffness. In particular, the cross member is torsionally softer than a conventional tubular profile by the partially U-shaped configuration of the cross section of the transverse profile. The fastening unit encloses the profile section of the cross member Outside. The fact that the shape of the fastening unit is adapted to the shape of the deformed profile section may mean that a cross-section of the fastening unit is an essentially to scale enlargement of the cross section of the deformed profile section. By way of example, the fastening unit can have two fastening elements that can be positively, positively and / or materially connected to one another. The actuator may also be attached via two or more corresponding fastening units on the transverse profile, the

may be arranged immediately adjacent or spaced from each other. In order to influence the torsional rigidity of the transverse profile only minimally, the distance of the fastening elements is chosen as small as possible.

In an advantageous manner, at least one, preferably elastomeric, damping element is arranged between the fastening unit and the deformed profile section. As a result, mechanical vibrations of the cross member are optimally damped transmitted to the actuator - conversely, no running noise of the actuator in the vehicle or the chassis are transmitted. The damping element may have a shape in cross section, which is also adapted to the shape of the cross section of the cross member and the fastening unit. The damping element can form-fit the profile section in the region of the fastening unit, for example by means of clamps. By the

Damping elements thus results in a further advantage of a decoupling from the cross member, so that the actuator does not have to absorb torsional forces of the cross profile. Thus, the actuator, e.g. its housing, are not adapted to a torsional stress or does not affect the torsional stiffness of the cross member.

According to an alternative and advantageous embodiment, it is provided that the cross member is at least partially V-shaped in cross-section, is opening in the direction of the actuator and has two in cross-section at an angle to each other arranged and interconnected legs, wherein the actuator via at least one fastening element attached to the thighs. Due to the at least partially V-shaped configuration of the transverse profile, the cross member has good torsional properties and a suitable flexural rigidity. Each fastener may be bolted to the respective leg, for example. The actuator may also be attached to at least one of the legs via two or more corresponding fastening elements.

In an advantageous manner, at least one fastening element is supported at least partially via at least one elastic, preferably elastomeric,

Damping element on the respective leg from. As a result, mechanical vibrations of the cross member are optimally attenuated transmitted to the actuator. A transmission of vibrations or running noise of the actuator in the

Suspension is avoided on the other as well. The damping element can form a bearing point on the respective leg, so that the respective fastening element is mounted in a floating manner on the respective leg via the damping element.

The invention is not limited to the specified combination of the features of the independent claim and the dependent claims. In addition, there are further possibilities for combining individual features from the patent claims, the following description of the exemplary embodiments or from the figures.

Preferred embodiments of the invention will be explained in more detail with reference to the accompanying figures. These show:

Fig. 1 is a schematic representation in perspective view of a first

Embodiment of a steerable trained twist beam axle,

FIG. 2 shows a side view of the steerable beam axle shown in FIG. 1, FIG.

3 is a perspective view of a sleeve bearing,

Fig. 4 is a schematic partial view in perspective view of a second

Embodiment of a steerable trained twist beam axle, 5 is a partial view of a torsion beam axle with double-walled cross member,

and

Fig. 6 is a partial view of a torsion beam axle with open cross member.

In Fig. 1, a steerable torsion beam axle 1 is designated for a motor vehicle not shown in detail, which can be used as a steerable rear axle of the same. The steerable torsion beam axle 1 has two spaced apart trailing arms 2, 3, which are each connected to the ends of a cross member 4 to form a torsion beam. At the respective trailing arm 2, 3 each have a suspension 8a and 10a pivotally mounted. The

Wheel suspension 8a, 10a has an integrally from a wheel 8, 10 and in the vehicle longitudinal direction adjoining the handlebar 5, 6. A steering axle 7, 9 is provided for the pivotable articulation of the wheel suspension 8a, 10a or ultimately of the wheel carrier 8, 10 with the handlebar 5, 6 on the trailing arm 2, 3.

The two steering axles 7, 9 have a spread at an angle to

Vertical axis on. The suspension 8a, 10a is articulated to the trailing arms 2 and 3 respectively via two elastomeric bearings, of which in FIG. 2, which, viewed in the direction of travel, shows the right end of the torsion beam axle 1, an upper elastomeric bearing 11 and a lower elastomeric bearing 12 are visible. In the perspective view of Figure 1, the wheel carrier 8 and 10 are shown, so that the upper elastomeric bearings 11 and 13 can be seen. The elastomeric bearings 11, 12 and 13 are on the one hand via fastening screws 14 in fork-shaped

extending fastening tabs 15 and 16 of the trailing arm 2 and 3 attached. On the other hand protrudes from each suspension 8a, 10a from a support arm 17 and 18, in which the respective sleeve-shaped elastomeric bearings 11, 12 and 13 is pressed to fix it.

As already explained, the steerable torsion beam axle 1 according to FIG. 1 has a twistable connecting the two trailing arms 2, 3

Cross member 4, which also takes over the function of a roll stabilizer. In addition, part of the steerable steering axle joint 1 is a with the

Wheel suspensions 8a, 10a connected actuator 19 for pivoting the

Wheel support 8, 10 about the steering axles 7, 9. An unspecified actuator of the actuator 19 engages via tie rod joints on two tie rods 20, 21, whose other ends via tie rod ends 22 and 23 each articulated to the handlebars 5, 6 in the form of Steering levers 24 and 25 of the two wheel carrier 8, 10 are connected.

The actuator 19 is mounted centrally on the cross member 4. In this case, the actuator 19 is attached via two fastening elements 26, 27 on the cross member 4, which enclose a deformed profile section of the cross member 4. In addition, it is apparent from the figure 1 that at each of the trailing arm 2, 3 seen at the front end in the direction of travel, a pivot bearing 28 and 29 is provided, via which the torsion beam axle 1 is articulated to a vehicle body of the motor vehicle. At the rear ends of the trailing arm 2, 3 spring plate 30 and 31 are formed, by means of which the torsion beam axle 1 is supported via abutment springs, not shown, to abutments of the vehicle body.

From Figure 2, which shows a right side view of the torsion beam axle 1 of Figure 1, the suspension 8a and thus the arrangement of the handlebar 5 on the wheel 8 shows, the handlebar 5 forms a steering lever 24 and the tie rod end 22 with the tie rod 20 is connected. Furthermore, the

Elastomeric bearings 11, 12 shown, which are fixed on the fastening straps 15, 16 and the fastening screws 14 on the trailing arm 2. The upper support arm 17 and a lower support arm 32 of the suspension 8a, 10a respectively engage the circumference of the elastomeric bearings 11 and 12. The steering axis 7, 9 respectively passes through the upper and lower sleeve bearings 11, 12, so that by means of the tie rods 20, 21 and the steering lever 24, 25 ultimately the wheel carrier 8, 10 are pivotable.

FIG. 3 shows one of the elastomer bearings 11, 12 or 13, which is embodied as a sleeve bearing 33 designed as a rubber-metal composite component. An inner sleeve 34 of this sleeve bearing 33 has a longitudinal bore 35 for one of the fastening screws 14 and is connected via a rubber element 36 with a Outer sleeve 37 connected. About this rubber element 36 can make a precise vote of the radial and axial stiffnesses to each other. in the

In the present case, the sleeve bearing 33 should, with a corresponding arrangement according to FIGS. 1 and 2, have a lower axial rigidity than the radial rigidity.

The rubber element 36 may also project axially beyond the outer sleeve 37 and thus form an axial abutment ring on both sides. In addition, the outer sleeve 37 may be conically formed on its outer shell and thereby fixed in correspondingly formed receiving bores of the support arms 17 and 18. In addition, there is also the possibility to dispense with the outer sleeves 37 and vulcanize the rubber element into the mounting holes.

4 shows a further perspective view of a steerable

Twist beam axis 1. Here, a cross member 43, at least in this section, seen in cross-section, designed as a one-sided in the direction of the wheel open V-shaped profile with a longitudinal opening 38.

The cross member 4 has two, seen in cross section, at an angle to each other

arranged and interconnected legs 39 and 40, wherein the actuator 19 is attached via at least one fastening element 41 and 42 respectively to the legs 39 and 40 respectively. The as screw connections and

Flange sections running fasteners 41 and 42 are bolted to the legs 39 and 40.

Fig. 5 shows a further embodiment example with a central region of a cross member 4, wherein the attachment of the actuator 19 to the

Embodiment corresponds to FIG. 1. The cross section of the cross member 4 is U-shaped. As can be seen from the illustration, a tube is at least partially pressed radially for this purpose, so that a doubled wall 48 is formed on the cross member 4. At this profile, the actuator 19 is secured by means of damping elements 44 and 45 by means of clamps 46 and 47, which enclose the cross member 4. FIG. 6 shows, as a further exemplary embodiment, a middle region of a cross member 43. In accordance with FIG. 4, the cross member 43 is designed as a V profile open on one side. The actuator 19 is disposed away from the longitudinal opening 38. On the legs 39 and 40 are secured by screws 49 and 50 holding elements 51 and 52, in which the actuator 19 via the

Fixing elements 41 and 42 is fixed.

Bezuaszeichen steerable twist beam axle

Trailing arm

crossbeam

handlebars

steering axle

wheel carrier

a suspension

steering axle

0 wheel carrier

0a wheel suspension

1 upper elastomeric bearing

2 lower elastomeric bearings

3 upper elastomeric bearing

4 fixing screw

5 fastening strap

6 fastening strap

7 support arm

8 support arm

9 actuator

0 tie rod

1 tie rod

2 tie rod end

3 tie rod end

4 steering levers

5 steering levers

6 fastener

7 fastening element

8 pivot bearings

9 pivot bearings spring plate

Spring plate lower support sleeve sleeve bearing

inner sleeve

Longitudinal bore rubber element outer sleeve

Longitudinal leg

leg

Fastener fastener cross member

Damping element Damping element Clamp

clamp

wall

screw

Holding element retaining element

Claims

claims

1. Steerable torsion beam axle (1) for a motor vehicle with a twistable cross member (4, 43) having at its two ends in each case a trailing arm (2, 3), with each trailing arm (2, 3) a suspension (8a, 10a ), which is in each case mounted pivotably about a steering axle (7, 9) on the respective trailing arm, the wheel suspension having a wheel carrier (8, 10) and a link (5, 6) adjoining it in the vehicle longitudinal direction, characterized that

each wheel suspension (8a, 10a) via at least two bearings (11, 12, 13),

preferably elastomeric bearing, is articulated to the respective trailing arm (2, 3), wherein at least one bearing (11, 12, 13) in the vehicle longitudinal direction at least compared to the vehicle vertical direction different, preferably lower, has stiffness.

2. Steerable torsion beam axle (1) according to claim 1, characterized

characterized in that the at least one bearing (11, 12, 13) as a sleeve bearing (33) is formed, wherein the sleeve bearing (33) on at least one, substantially horizontally from the trailing arm (2, 3) outgoing fastening tab (15, 16) received is, wherein the suspension (8a, 10a) at least two each an outer sleeve (37) of the sleeve bearing (33) receiving support arms (17 and 18), wherein between the outer sleeve (37) and an inner sleeve (34) has an elastic element (36 ) is arranged with respect to the axial stiffness higher radial stiffness and that the inner sleeve (34) with the fastening tabs (15, 16) positively and / or cohesively coupled.

3. Steerable torsion beam axle (1) according to claim 2, characterized

in that the outer sleeve (37) is integral with the at least one

Support arm (17, 18) is formed.

4. steerable torsion beam axle (1) according to claim 1, 2 or 3, characterized in that a, preferably double-acting actuator (19) approximately, preferably exactly, centrally on the cross member (4, 43) is arranged, wherein the Actuator for carrying out a steering movement about the steering axles (7, 9) with the respective suspension (8a, 10a), preferably the handlebars (5, 6) is coupled.

5. Steerable torsion beam axle (1) according to one of the preceding

The crossbeam (4) is formed by a tube which is inwardly deformed at least partially along its longitudinal extent and is U-shaped at least over a partial region, seen in cross-section, wherein the actuator (19) has at least one Fastening element (46, 47) on the cross member (4) is fixed, which encloses a profile section of the cross member (4) and has a shape which is adapted to a shape of the profile section.

6. Steerable torsion beam axle (1) according to claim 5, characterized in that a transverse profile of the cross member (43), seen in cross section, at least over a partial area, V-shaped, with in the direction of the actuator (19) open longitudinal profile, and in that the actuator (19) is fastened in each case to at least one fastening element (41, 42) on legs (39, 40) of the cross member (43).

7. Steerable torsion beam axle (1) according to one of the claims 5 or 6, characterized in that at least one fastening element (41, 42) at least partially via at least one elastic damping element (44, 45) on the cross member (4, 43) or the Fastening element (46, 47) is supported.