FORM 2
THE PATENT ACT 197 0 (39 of 1970)
The Patents Rules, 2003 COMPLETE SPECIFICATION {See Section 10, and rule 13)


1. TITLE OF INVENTION
STABILISER DEVICE WITH WHEEL GUIDE CONTROL ARM

2. APPLICANT(S)
a) Name
b) Nationality
c) Address

ZF FRIEDRICHSHAFEN AG GERMAN Company 88038 FRIEDRICHSHAFEN GERMANY

3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -


The invention relates to a stabiliser device of a vehicle axle with a roll stabiliser according to the preamble of Claim 1.
Vehicle axles according to the type in question, in the case of which the roll stabiliser is actuated directly by a wheel guide control arm - for example by a tension strut or compression strut of the wheel suspension - connected to the roll stabiliser are in the first place advantageous in so far as a stabiliser transmission ratio of 1:1 can thereby be achieved. In other words, this means that the deflection movements of the wheel are converted into a corresponding torsional movement of the stabiliser not just proportionally - as in the case of traditional transverse stabilisers with a pendulum support articulation - but rather in each case to the full extent. It is therefore possible to use, for example, correspondingly thinner and therefore lighter stabilisers for directly actuated stabiliser devices of this kind.
Furthermore, both the usual articulations of the stabiliser ends via individual pendulum supports with two ball-and-socket joints in each case and the usual bent stabiliser legs are eliminated with this design, in which the stabiliser is directly attached to the wheel guide control arm, as a result of which weight is also saved and in addition valuable construction space is created in the area of the wheel suspension.
Such generic stabiliser devices are known, for example, from DE 10 2004 020 073 Al or from EP 1 564 041 A2. In the case of these known stabiliser devices a respective wheel guide control arm, which is formed as a tension strut, of a wheel suspension is directly attached with its chassis-side end to one end of the roll stabiliser. This results on the one hand in a stabiliser transmission ratio of 1:1 and on the other in the elimination of the usual expensive, separate articulation of the stabiliser by means of pendulum supports.
However the method of attaching the chassis-side end of the wheel guide control arm to the stabiliser end is comparatively expensive in these known stabiliser
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devices. Furthermore, where the stabiliser devices known from the prior art are concerned, the wheel guide forces which are transmitted via the wheel guide control arm are introduced into the axle carrier or into the vehicle chassis via the stabiliser as well as via the stabiliser bearings. However, as the stabiliser and the stabiliser bearings are not in the first place designed to absorb wheel guide forces and introduce them into the vehicle chassis, considerable compromises must generally be made with regard to the introduction of forces and vibration damping in the solutions which are known from the prior art.
With regard to the attachment of the wheel guide control arm to the stabiliser end, a further aggravating factor is that the axis of rotation of the stabiliser extends in the transverse direction of the vehicle, while the axes of rotation of the wheel guide control arms, for example the axes of rotation of the tension struts or compression struts in question, generally extend at an acute angle to the transverse direction of the vehicle. Should the chassis-side end of a wheel guide control arm be directly articulated to the roll stabiliser, the axis of rotation of the wheel guide control arm extending at an acute angle to the transverse axis of the vehicle must therefore be converted into the axis of rotation extending in the direction of the transverse direction of the vehicle, which in the prior art gives rise to further considerable structural expenditure in the area of the connection of the wheel guide control arm and roll stabiliser.
Against this background, the object of the present invention is to provide a wheel-guiding stabiliser device with which the above-mentioned disadvantages present in the prior art are overcome. In this respect the stabiliser device should in particular enable the chassis-side end of the wheel guide control arm to be articulated to the roll stabiliser and to the chassis or axle carrier in a simple and at the same time sturdy manner. Furthermore, as compared with the prior art, improvements with regard to the construction space required by the stabiliser device as well as simplifications in mounting the stabiliser and axle are to be achieved.
3 17 APR 2009

This object is achieved by a stabiliser device having the features of Claim 1.
Preferred embodiments constitute the subject matter of the subclaims.
In a manner which is primarily known per se, the stabiliser device according to the invention is intended for use on a vehicle axle with a roll stabiliser, the axle having at least one wheel guide control arm for each wheel. In a manner which is primarily likewise known, the chassis-side articulation of the wheel guide control arm is connected to the associated end area of the roll stabiliser such that a twisting actuation of the roll stabiliser takes place directly due to deflection movements of the wheel guide control arm.
The stabiliser device is distinguished by the fact that the roll stabiliser is rigidly connected to the chassis-side end area of the wheel guide control arm.
The rigid - i.e. jointless - connection of the stabiliser end to the control arm end is in this respect primarily of advantage in so far as the structurally expensive and tendentiously susceptible, flexible attachment of the wheel guide control arm to the stabiliser end is thus completely eliminated. Moreover, a completely play-free, direct conversion of the deflection movement of the control arm into a corresponding rotational movement of the stabiliser is thus rendered possible, whereby the desirable direct response of the stabiliser is also further improved.
When compared with the traditional attachment of the roll stabiliser via pendulum supports, this.arrangement additionally affords the advantage of eliminating both the pendulum supports and the comparatively expensive mounting thereof, that, furthermore, instead of separate mountings for the stabiliser and the chassis-side end of the wheel guide control arm, just one common mounting for the control arm and the stabiliser per vehicle side is necessary, and that, in addition to this, it is possible to eliminate the bent-over stabiliser ends, which simplifies the production of the stabiliser and reduces its mass.
4 17 APR 2009

In addition to this, further advantages are achieved which relate in particular to the simple, uncomplicated mounting of the stabiliser on the vehicle and corresponding cost savings.
This is in particular also based on the knowledge that - on account of the axes of rotation of the wheel guide control arm and stabiliser not being parallel, but rather extending at an acute angle to one another - the bending of the stabiliser induced when the wheel guide control arm and the stabiliser are rigidly connected proves to be comparatively slight and can therefore be easily accommodated by most stabiliser configurations.
On account of the bending of the roll stabiliser in the transverse direction of the vehicle, which is linked to the deflection movements of the wheel guide control arm, this arrangement is in particular - although by no means exclusively - suitable for use with thinner stabilisers, as are used, for example, in the case of lighter vehicles, or on rear vehicle axles.
According to the invention, the chassis-side articulation of the wheel guide control arm is formed as a ball-and-socket joint. This results in particular in improved absorption of the secondary moments and forces produced by the bending of the stabiliser as well as a more direct transmission of the deflection movements of the wheel guide control arm to the stabiliser and therefore also to the wheel guide control arm of the opposite vehicle side.
Although the overall stiffness of the system consisting of the wheel guide control arm and the two bearing points of the wheel guide control arm is in the first place increased by using a ball-and-socket joint instead of an elastomer bearing to attach the wheel guide control arm to the vehicle chassis, the overall stiffness of the wheel guide control arm can be reset as desired by means of appropriately altering the wheel-side hinge point of the wheel guide control arm. On account of the considerably softer setting of the wheel-side elastomer bearing of the wheel guide
5 17 APR 2009

control arm which is thus rendered possible, on the one hand improved acoustic uncoupling can be achieved and on the other costs can thereby be saved, as, for example, a soft rubber bearing, in particular without an intermediate tube, can be used for the wheel-side hinge point - as is also provided according to a further embodiment of the invention.
According to a further, particularly preferred embodiment of the invention, the ball pin of the ball-and-socket joint with which the wheel guide control arm is attached on the chassis side is disposed on the side of the chassis-side end of the wheel guide control arm which faces the wheel. This results in a particularly simple and direct, substantially rectilinear attachment of the torsion bar end to the chassis-side end of the wheel guide control arm, as in this embodiment the ball pin and the torsion bar end can be disposed on diametrically opposite sides of the ball-and-socket joint.
According to a further embodiment of the invention, the joint housing of the ball-and-socket joint is formed by the actual wheel guide control arm. This embodiment provides particularly compact, space- and weight-saving configuration possibilities, which are also accompanied by high torsional stiffness, for the wheel guide control arm.
According to a further, alternative embodiment of the invention, the joint housing of the ball-and-socket joint is pressed into the wheel guide control arm. This embodiment is particularly well suited for built-up wheel guide control arms, for example for wheel guide control arms which are composed of sheet metal deep-drawn parts. Against this background, according to further, likewise preferred embodiments of the invention, the front side of the joint housing is beaded outwards and/or inwards on the ball pin side.
The outward beading results in the first place in a simple, play-free and secure fastening of the joint housing, in particular when using built-up or deep-drawn wheel guide control arms. On the other hand, simultaneous radially outward and
6 17 APR 2009

inward beading of the front side of the joint housing which is on the ball pin side can be used in the sense of an advantageous dual function both to fasten the joint housing in the control arm and to fix the joint housing cover which is on the ball pin side as well as the sealing bellows to the joint housing.
The invention is in the first place implemented irrespective of the structural form of the rigid connection of the roll stabiliser to the chassis-side end area of the wheel guide control arm, as long as the torques and forces which are to be transmitted can be absorbed by the connection between the wheel guide control arm and the roll stabiliser.
However, according to a particularly preferred embodiment of the invention, the rigid connection between the end of the roll stabiliser and the chassis-side end area of the wheel guide control arm is in the form of substantially prismatic cormecting areas of the roll stabiliser and the wheel guide control arm. This embodiment is advantageous in so far as length tolerances of the stabiliser - as well as the effects of other tolerance chains between the left-hand and the right-hand vehicle side of the motor vehicle - can be easily compensated through a corresponding displacement of the prismatic connecting areas, which are complementary in shape, of the roll stabiliser and the wheel guide control arm when the stabiliser is mounted.
In this respect the connection between the roll stabiliser and the chassis-side end area of the wheel guide control arm comprises, for example, a substantially annular connecting clamp, the connecting clamp embracing the complementarity shaped connecting areas of the roll stabiliser and the wheel guide control arm like a ring and pressing them onto one another. The connecting clamp is preferably formed as a screw clamp by which the two connecting areas of the roll stabiliser and the wheel guide control arm can be pressed against one another by a screw fitting contained in the connecting clamp. This in particular makes it even easier to mount the stabiliser.
7 17 APR 2009

According to a further preferred embodiment of the invention, the stabiliser has at least one length compensation area which is bent substantially in the shape of an S. Strains between the wheel suspensions of the left-hand and the right-hand vehicle side can be prevented as a result of a length compensation area disposed in the stabiliser, as bending and the effective changes in length of the stabiliser which are linked with this and which occur upon deflection of the wheel guide control arm rigidly connected to the stabiliser are accommodated by the length compensation area and can be rendered harmless.
Finally, according to a particularly preferred embodiment of the invention, the wheel guide control arm is a tension strut or a compression strut of a wheel suspension. Although the invention can in principle be applied in diverse control arms forms, such as transverse control arms, diagonal control arms or longitudinal control arms, it is particularly advantageous to use the invention in conjunction with a tension strut or a compression strut in so far as the acute angle between the pivot axis of the strut and the axis of rotation of the stabiliser is particularly small in the case of a tension or compression strut. This results in particularly slight bending as well as a particularly direct transmission ratio and actuation of the stabiliser when the wheel guide control arm executes a deflection movement. Moreover, in this embodiment of the invention the roll stabiliser can be disposed in a particularly space-saving manner in the respective front or rear area of the axle carrier - in which the tension or compression strut is also articulated - without any problems regarding construction space.
The invention is illustrated in detail in the following on the basis of a drawing which represents just one embodiment. The single
Fig. shows in a schematic representation the attachment between the wheel guide control arm and the stabiliser end in an embodiment of a stabiliser device according to the invention in a view from below.
17 APR 2009

The fig. shows the attachment between a wheel guide control arm 1 and the associated end 3 of a roll stabiliser 2 in an embodiment of a stabiliser device according to the present invention viewed from the underside of the vehicle. The stabiliser end 3 which, related to the direction of travel, is on the left-hand side as well as the chassis-side end area of the associated wheel guide control arm 1 of the left-hand wheel are represented in the fig. Here the direction of travel of the associated vehicle extends downwards related to the drawing, as indicated by the broken arrow D.
The fig. in the first place shows the end region 3 on the left-hand side, related to the vehicle, of the roll stabiliser 3, which here is of solid formation, of the vehicle; also the chassis-side end area of a wheel guide control arm 1, which is also only represented in part and which in the present case is a tension strut of the wheel suspension of one of the left-hand wheels of a motor vehicle.
The end 3 represented in the fig. of the roll stabiliser 1 is connected rigidly as well as non-rotatably to a connecting extension 5, which is integrally formed on the end area of the wheel guide control arm 1, by means of a connecting clamp 4 which is press-moulded or mounted by means of a screw fitting (not represented).
The chassis-side articulation of the wheel guide control arm 1 is in the form of a ball-and-socket joint 6. Here the chassis-side end of the wheel guide control arm 1 at the same time forms the joint housing of the ball-and-socket joint, while the ball pin 7 of the ball-and-socket joint 6 is connected to the vehicle chassis or to an axle carrier 8 (not represented in detail).
According to the fig., the connecting line 10' extending through the centre point of the joint ball 9 points with the tip of its arrow in the direction of the wheel-side articulation point of the wheel guide control arm 1, at which the wheel guide control arm 1 is connected to the wheel carrier (not represented for reasons of space) of the associated wheel of the motor vehicle.
17 APR 2009

This means that during deflection movements of the associated wheel the wheel guide control arm 1 - in its position represented according to the fig. - pivots about the axis of rotation 10 drawn as a dotted line. Therefore the axis of rotation 10 of the wheel guide control arm 1 does not correspond with the axis of rotation 11, defined by the ball-and-socket joint 6 (and its counterpart on the other side of the vehicle), of the roll stabiliser 2. Instead the axes of rotation 10 and 11 of the wheel guide control arm 1 and the roll stabiliser 2 form the acute angle a. For this reason the roll stabiliser 2 is not pivoted or twisted about its own axis 11 during deflection movements of the wheel guide control arm 1, but rather additionally undergoes a certain bending, which extends opposite to the direction of the deflection movement of the wheel guide control arm 1.
In other words, this means that, when a wheel of the motor vehicle is deflected inwards - i.e. upwards related to the vehicle - the roll stabiliser 2 bends downwards related to the vehicle. However it has become apparent that this bending of the roll stabiliser lies in the range of a few angular degrees and, moreover, is practically negligible from the viewpoint of the bending load, which is linked with this, on the stabiliser. Furthermore, any effective changes in length of the stabiliser 2 linked with the bending of the stabiliser 2 - that is changes in the distance between the stabiliser ends 3 - are neutralised at the stabiliser 2 by the relieving arch 12, so that there are also no appreciable strains between the left-hand and the right-hand wheel suspension on account of the bending of the stabiliser.
Therefore, due to the rigid connection according to the invention between the stabiliser end 3 and the chassis-side end of the wheel guide control arm 1, when compared with the prior art, in which the roll stabiliser is actuated directly by a wheel guide control arm flexibly connected to the roll stabiliser, the result is a quite considerable structural simplification of the axle structure, with the corresponding advantageous consequences with regard to easier mounting and saving of costs.
1 7 APR 2009

When compared with the usual articulation of the roll stabiliser via pendulum supports, significant advantages are additionally obtained by the invention with regard to the omission of the pendulum supports and the mounting thereof, also both by the elimination of the chassis-side elastomer bearing of the wheel guide control arm and by the omission of additional mountings of the stabiliser, in the form of the wheel-side elastomer bearing, which can be made softer and more cost-effective, of the wheel guide control arm, as well as, finally, in the form of the stabiliser, which can be made shorter, with a simpler shape and therefore more cost-effective and lighter.
As a result, it therefore becomes clear that, in consequence of the invention, a stabiliser device is provided which, when compared with the prior art, is accompanied by substantial advantages with regard to a simplified articulation, which is sturdy in operation, of the wheel guide control arm to the roll stabiliser as well as to the vehicle chassis. In this respect, as compared with the prior art, improvements are also achieved with regard to the required construction space as well as simplifications in mounting the stabiliser and axle.
The invention therefore makes a substantial contribution with regard to structural improvement as well as in terms of cost savings in the production and mounting of wheel-guiding stabiliser devices, in particular for use in axle systems subject to high requirements relating to vehicle dynamics.
17 APR 2009
ii

List of reference characters

1 wheel guide control arm, tension strut
2 roll stabiliser
3 stabiliser end
4 connecting clamp
5 connecting extension
6 ball-and-socket joint
7 ball pin
8 axle carrier
9 joint ball
10 pivot axis
10' longitudinal axis
11 pivot axis
D direction of travel

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1 7 APR 2009

WE CLAIM:
1. Stabiliser device of an axle of a vehicle/ the axle comprising a roll stabiliser (2)
as well as at least one wheel guide control arm (1) for each wheel, wherein the
chassis-side articulation (6) of the wheel guide control arm (1) is connected to
an end area (3) of the roll stabiliser (2) such that a twisting actuation of the roll
stabiliser (2) takes place due to a deflection movement of the wheel guide
control arm (1), wherein the roll stabiliser (2) is rigidly connected to the
chassis-side end area of the wheel guide control arm (1),
characterised in
that the chassis-side articulation of the wheel guide control arm (1) is formed
as a ball-and-socket joint (6).
2. Stabiliser device according to Claim 1,
characterised in
that the wheel-side articulation of the wheel guide control arm (1) is formed as a rubber bearing without an intermediate tube.
3. Stabiliser device according to either of Claims 1 and 2,
characterised in
that the ball pin (7) of the ball-and-socket joint (6) is disposed on the side of the wheel guide control arm (1) which faces the wheel.
4. Stabiliser device according to any one of Claims 1 to 3,
characterised in
that the joint housing of the ball-and-socket joint (6) is formed by the wheel guide control arm (1).
5. Stabiliser device according to any one of Claims 1 to 3,
characterised in
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that the joint housing of the ball-and-socket joint (6) is pressed into the wheel guide control arm (1).
6. Stabiliser device according to Claim 5,
characterised in
that the front side of the joint housing is beaded outwards on the ball pin side.
7. Stabiliser device according to Claim 5 or 6,
characterised in
that the front side of the joint housing is beaded inwards on the ball pin side.
8. Stabiliser device according to any one of Claims 1 to 7,
characterised in
that the rigid connection of the roll stabiliser (2) to the chassis-side end area of the wheel guide control arm (1) is in the form of substantially prismatic connecting areas (5) of the roll stabiliser (2) and the wheel guide control arm
1)-
9. Stabiliser device according to Claim 8,
characterised in
that the connection of the roll stabiliser (2) to the chassis-side end area of the wheel guide control arm (1) comprises a substantially annular connecting clamp (4) embracing the connecting areas (5) of the roll stabiliser (2) and the wheel guide control arm (1).
10. Stabiliser device according to Claim 9,
characterised in
that the connecting clamp (4) is formed as a screw clamp.
1 7 APR 2009

11. Stabiliser device according to any one of Claims 1 to 10,
characterised in
that the roll stabiliser (2) has at least one length compensation area (12) which is bent substantially in the shape of an S.
12. Stabiliser device according to any one of Claims 1 to 11,
characterised in
that the wheel guide control arm (1) is a tension strut or compression strut of a wheel suspension.
Dated this 15th day of April, 2009

HIRAL CHANDRAKANT JOSHI AGENT FOR ZF FRIEDRICHSHAFEN AG

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17 APR 2009