FORM 2
THE PATENT ACT 1970 (39 of 1970)
&
The Patents Rules, 2003 COMPLETE SPECIFICATION
(See Section 10, and rule 13)
1.TITLE OF INVENTION
GUIDING ELEMENT FOR A TRACK ELEMENT IN A WHEEL SUSPENSION OF A
VEHICLE

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

ZF FRIEDRICHSHAFEN AG
GERMAN Company
8803 8 FRIEDRICHSHAFEN
GERMANY

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

ENGLISH TRANSLATION VARIFICATION
CERTIFICATE u/r. 20(3)(b)
I, Mr. HIRAL CHANDRAKANT JOSHI, an authorized agent for the applicant, ZF FRIEDRICHSHAFEN AG do hereby verify that the content of English translated complete specification filed in pursuance of PCT International application No. PCT/DE2006/001743 thereof is correct and complete.

Description
The invention relates to a guide element for a guide track element in a wheel suspension of a vehicle, one of which elements is essentially fixedly disposed on the body and the other element is essentially fixedly disposed on the wheel, and a slide bearing permitting a sliding movement of the guide element on the guide track element is disposed between these elements. The prior art is to be found in German patent application DE10 2004 048 789, as yet unpublished, in particular.
Conventional wheel suspensions satisfy the kinematic and elasto-kinematic requirements placed on guiding the vehicle wheel with kinematic chains of steering arms and articulated joints, which guide the wheel support and hence the wheel relative to the vehicle structure. The double transverse steering arm principle and its variants such as three-dimensional steering arms or five-arm axles have proved effective when it comes to high demands on driving dynamics and driving comfort, for example. Also known from the prior art are wheel guides with physically designed so-called guide track elements, along which guide elements are able to slide. The old German patent specification DE 613 775, for example, discloses a steerable rigid axle with a wheel guide in the vertical direction, which is formed by a linear, essentially vertically oriented guide tube rigidly joined to the wheel support, inside which a spindle supported on the rigid axle is guided so that it can slide longitudinally. A single wheel suspension of similar construction is disclosed in US patent US 2,992,013.
In previously unpublished German patent application DE 10 2004 048 789 mentioned above, a vehicle wheel guide is additionally provided with physically designed guide track elements on which so-called guide elements are disposed so that they can slide longitudinally. In particular - by contrast with the mentioned relatively old prior art -guide track elements extending in a three-dimensional curve are disclosed here. Roller-mounted guide elements are able to slide on or along them and the guide track element is preferably secured to the body or structure of the vehicle, whilst the


associated guide element is mounted on the respective vehicle wheel and is thus secured to a wheel support or similar. (It is also pointed out that the reverse arrangement is also possible). In this patent application, there is also mention of the possibility of providing a slide bearing between the guide element and the guide track element.
The intention is to propose a practically designed slide bearing for such a unit comprising a guide element and guide track element in a vehicle wheel suspension of the type outlined in the introductory part of claim 1 (= objective of this invention).
The solution to this objective is characterised in that the guide element is guided in a rotating movement and/or pivoting movement on the guide track element by an articulated joint arrangement, inside which is disposed at least one slip bearing ring which is guided on the guide track element by its passage orifice. In preferred embodiments, the articulated joint arrangement is provided in the form of a rubber bush or in the form of a ball and socket joint. Advantageous features are set out in the dependent claims.
In order to provide a wheel guide that is suitable with respect to the vehicle driving dynamics, it is necessary to use a guide track running in a curve with a radius that is not three-dimensionally constant and a corresponding guide track element with a different curvature at different points. However, a simple, conventional slide bearing solution cannot be used for such a curved guide track. What is proposed, therefore, is a combination of a suitable joint for providing an angular movement necessary due to the curved guide track and at least one slide bearing element which is disposed in this joint or a corresponding so-called articulated joint arrangement.
This slide bearing element is at least one so-called slip bearing ring, which is mounted in a hollow body of the articulated joint arrangement.
The joint arrangement therefore permits at least a slight rotating movement and/or


pivoting movement of the guide element relative to the guide track element, which must be effected as the guide element is pushed on a mostly non-constantly curved guide track element in the direction of the longitudinal axis of the guide track element. By a pivoting movement is meant a pivoting of the guide element about an axis extending perpendicular to the axis of the guide track element at the relevant point at which the guide element is disposed relative to the guide track element at any one time, whereas a rotating movement means a turning of the guide element about the relevant axial portion of the guide track element at any one time.
The proposed articulated joint arrangement should now permit these movements and to this end may preferably be provided in the form of an elastomeric rubber bush or in the form of a ball and socket joint. In the case of a so-called "elastomer joint" (= "rubber bush"), an inner sleeve and an outer sleeve disposed concentrically with it may be provided, between which an elastomer layer is provided to create the required articulation. Said slip bearing ring(s) may then be provided inside the inner sleeve. In the case of a ball and socket joint, on the other hand, said slip bearing ring(s) may be provided inside a so-called spherical layer-hollow body. The spherical layer in this instance is a body derived from a sphere and created by cutting off two oppositely lying sphere segments. The so-called spherical layer-hollow body is then mounted so that it can turn in a spherical shell provided in the guide element or in a housing or in a sleeve of a housing in order to form the ball and socket joint. The at least one slip bearing ring disposed in the spherical layer-hollow body is slidably guided on the guide track element and thus guides the spherical layer-hollow body and hence also the housing or sleeve of the guide element on the guide track element.
The same applies in the aforementioned case of the "elastomer joint" with regard to said inner sleeve and outer sleeve. Furthermore, the articulated joint arrangement may be based on a combination of a ball and socket joint and an elastomer joint, in which case the outer sleeve of the elastomer joint or the rubber bush mentioned above is disposed in a spherical layer-hollow body or designed as one, for example, so that the elastomer joint is practically mounted in a ball and socket joint.


The guide track element preferably has a circular cross-section, so that the passage orifice in the slip bearing ring adapted to it is likewise of a circular shape, thus enabling it to be turned about its longitudinal axis in addition during the course of a movement along the guide track element in particular. For reasons of strength, the slip bearing ring should have a certain minimum thickness or height (as viewed in the direction of the longitudinal axis of the guide track element). In order to permit an exact as possible guiding action of the slip bearing ring by the guide track element in spite of the curved portions of the guide track element, a slight relative movement should be possible between the inner portion of a slip bearing ring facing the guide track element and its outer portion facing the spherical layer-hollow body or inner sleeve of the so-called rubber bush (= elastomer joint). In a preferred embodiment, the slip bearing ring may itself have an elastomer ring for this purpose, with a metal bush vulcanised onto the external face and a plastic slip ring vulcanised onto the internal face, which lies with its internal face against the guide track element. The slip bearing ring (in its entirety) is mounted by means of the metal bush in the previously mentioned spherical layer-hollow body or in the inner sleeve of the rubber bush, and the inner sleeve of the rubber bush may itself be said metal bush, whilst the elastomer ring generates the ability between the plastic slip ring forming said inner portion and the metal bush forming said outer portion to move slightly. Both the outer metal bush and the inner plastic slip ring are preferably fixedly joined to the elastomer ring by vulcanisation. The elastomer layer of the elastomer ring is used to transmit the forces from the plastic slip ring to the metal bush in order to compensate for component tolerances and permits the above-mentioned ability of the inner portion of the side bearing ring to move slightly relative to its outer portion, thereby constituting a guide track with variable radius.
The forces which have to be transmitted between the guide element and the guide track element may be relatively high, as a result of which the slide bearing must be relatively thick or high for reasons of strength. However, due to the curved portions, this makes it more difficult to obtain an exact guiding action in spite of providing the elastomer material, for which reason it is also proposed that several slip bearing rings


be provided, disposed one above the other, the respective internal face portions of which facing the guide track element are in turn able to slide slightly against one another due to the respective elastomer rings and namely in directions perpendicular to the longitudinal axis of the guide track elements. These several slip bearing rings for generating the requisite angular movement are then mounted and secured by their external faces as a packet, i.e. by their portion facing away from the guide track element, in the spherical layer-hollow body or in the inner sleeve of the rubber bush or the elastomer joint. The several slip bearing rings offer the option of a modular system and a corresponding appropriate number of slip bearing rings needed as a function of the force to be transmitted can be provided, and it should (again) be pointed out that the elastomer rings stacked one above the other do not have to be secured from the outside in a separate metal bush or similar and instead, the metal bush surrounding the elastomer rings on the outside may be formed by the inner sleeve of said elastomer joint or said rubber bush or by the spherical layer-hollow body itself.
The cross-section of the plastic slip ring is preferably shaped so as to result in an optimum transmission of the forces via the elastomer ring to the outer metal bush and the magnitude of the transmittable force will also depend on the materials used. In order to obtain a best possible seating of the plastic slip ring on the guide track of the guide track element under all possible operating conditions, the internal face of the plastic slip ring is preferably of a rounded shape, i.e. provided with a radius.
Finally, it is proposed that the entire unit comprising the guide element and the guide track element be sealed by means of one but preferably two bellows for protection against dust, dirt and moisture. To this end, at least one bellows or similar may be disposed on the guide element extending essentially along the guide track element, by means of which the gap between the guide element and the guide track element is screened off from any dirt across the total possible displacement path of the guide element on the guide track element. The bellows is preferably of a split design and is secured by one part provided above the guide element and a part provided


underneath the guide element to the guide element or its housing respectively.
The invention will be described below in more detail with reference to examples of
preferred embodiments illustrated in the appended drawings, of which
Fig. 1 is an abstracted view showing a section through a guide element proposed by
the invention with a ball and socket joint with a portion of the co-operating guide
track element,
Fig. la shows detail X from Fig. 1 on a slightly larger scale,
Fig. 2 is a three-dimensional half-section of a co-operating slip bearing ring, whilst
several such slip bearing rings are illustrated in
Fig. 3 with a portion of a part of the spherical layer-hollow body constituting the ball
and socket joint. Similarly, the diagram of
Fig. 4 shows several slip bearing rings in a portion of a rubber bush, constituting a
so-called "elastomer joint" as an alternative to said ball and socket joint.
Fig. 5a illustrates another variant, based on a combination of a ball and socket joint
and an elastomer joint and
Fig. 5b shows a single slip bearing ring of this variant (without an external metal
bush).
Finally, Fig. 6 shows an external view of the unit comprising the guide element and
guide track element.
Turning firstly to Fig. 1, reference number 1 denotes a so-called guide track element on which a so-called guide element 2 is guided in longitudinal displacement. These two elements 1, 2 form a constituent part of a wheel suspension of an automotive vehicle, and the guide track element 1 is secured in a manner not illustrated to the vehicle body, whilst the guide element 2 is secured - likewise in a manner not illustrated - to a wheel of the vehicle. Naturally, the vehicle body is supported - in the usual way - on the wheel by means of a spring-damper arrangement. Relative movements between the vehicle body and wheel, such as usually occur in essentially the vertical direction, are defined in terms of their exact movement by, amongst other things, the unit comprising the guide track element 1 and guide element 2, and the


guide track element 1 is of an at least slightly curved design, in other words the guide track defined by this guide track element extends in a three-dimensionally curved arrangement.
In the embodiment illustrated as an example in Fig. 1, the guide element 2 has a housing 2a, inside which is disposed an articulated joint arrangement 3, in this instance in the form of a ball and socket joint 3', which is formed by a spherical shell 3a formed in the housing 2a, in which a so-called spherical layer-hollow body 3b is mounted so as to be rotatable in the manner of a joint ball of a ball and socket joint. Disposed in this spherical layer-hollow body 3b is a packet of slip bearing rings 4 stacked one above the other, which are fitted on the guide track element 1 and guided by their corresponding inner portion by this guide track element 1 by means of their circular passage orifices 4d (see Fig. 2).
The structure of such a slip bearing ring 4 is illustrated in Fig. 2. The so-called inner portion is formed by a plastic slip ring 4a, the inner edge of which lies against the guide track element 1. This plastic slip ring 4a is vulcanised by means of the outer edge onto the inner edge of an elastomer ring 4b, the outer edge of which is vulcanised onto a metal bush 4c. By means of the latter, the slip bearing ring 4 is secured in the spherical layer-hollow body 3b and in a central, cylindrical recess thereof, as may be seen from Fig. 3 showing a portion of this spherical layer-hollow body 3b opened up. As may also be seen here, several slip bearing rings 4 are stacked one above the other and this stack is closed off both at the top (as illustrated) and at the bottom (not illustrated) by a retaining cover 5. The intention and purpose of the structure of these slip bearing rings 4 were explained in more detail above and it should be reiterated here that the elastomer rings 4b are primarily intended to ensure a slight movement of the individual plastic slip rings 4a in the direction perpendicular to the longitudinal axis of the guide track element 1.
Fig. 4 illustrates an articulated joint arrangement 3 in the form of a rubber bush 3" rather than a ball and socket joint 3', which may also be referred to as an elastomer


joint 3". This rubber bush 3" or this articulated joint arrangement 3 in the form of an elastomer joint 3" comprises a hollow cylindrical outer sleeve 3c, inside of which an inner sleeve 3e is joined with an elastomer layer 3d disposed concentrically in between. As with the spherical layer-hollow body 3b illustrated in Fig. 3, slip bearing rings 4 stacked one above the other are disposed inside this hollow cylindrical inner sleeve 3e, each comprising a plastic slip ring 4a, an elastomer ring 4b and a so-called metal bush 4c, with a top (and bottom, although not illustrated) retaining cover 5.
Fig. 5a illustrates a combination of ball and socket joint 3' and elastomer joint 3", where the outer sleeve 3c of the elastomer joint 3" is mounted in a spherical layer-hollow body 3b constituting an integral part of a ball and socket joint 3'. In the embodiment illustrated as an example and by contrast with the embodiment illustrated in Figures 2, 3, the so-called metal bush 4c of the slip bearing rings 4 stacked one above the other simultaneously assumes the role, as an integral component (comprising all the slip bearing rings 4) of the inner sleeve 3e of the elastomer joint 3" or rubber bush 3", which is of particular advantage in terms of mounting space. As illustrated in Fig. 5b, the individual slip bearing ring 4 does not have a separate metal bush 4c.
Fig. 1 also illustrates a bellows 6 split into two parts, with the top part 6a and the bottom part 6b, which cover(s) the unit comprising the guide track element 1 and guide element 2 on the outside. By means of their ends facing the guide element 2, parts 6a and 6b of the bellows 6 are secured in clamping grooves 7 on the guide element 2 and by the other ends are secured on the guide track element 1 in the same manner (see also Fig. 6).
The proposed slide bearing solution designed to provide a bearing for a guide element 2 on a guide track element 1 in a wheel suspension of an automotive vehicle makes it possible to opt for a three-dimensionally curved guide track, such as needed for wheel suspensions in particular. Compared with roller bearing solutions which are likewise possible, there are advantages in terms of costs, weight and the demands


placed on the surface quality and dimensional accuracy of the guide track, and it should also be pointed out that a number of details could perfectly well be designed differently from the explanations given above without departing from the scope of the claims.


List of reference numbers

1 Guide track element
2 Guide element
2a Housing
3 Articulated joint arrangement
3' Ball and socket joint
3" Rubber bush / elastomer joint
3a Spherical shell
3b Spherical layer-hollow body
3c Outer sleeve
3d Elastomer layer
3e Inner sleeve
4 Slip bearing rings
4a Plastic slip ring
4b Elastomer ring
4c Metal bush
4d Passage orifices
5 Retaining cover
6 Bellows
6a Top part
6b Bottom part
7 Clamping groove


CLAIM:
1. Guide element (2) for a guide track element (1) in a wheel suspension of a vehicle, one of which elements (1 or 2) is essentially fixedly disposed on the body and the other element (2 or 1) is essentially fixedly disposed on the wheel, and a slide bearing permitting a sliding movement of the guide element (2) on the guide track element (1) is provided between these elements (1, 2), characterised in that the guide element (2) is guided on the guide track element (1) in a rotating movement and/or pivoting movement by means of an articulated joint arrangement (3) inside which is disposed at least one slip bearing ring (4), which is guided on the guide track element (1) by its passage orifice (4d).
2. Guide element as claimed in claim 1,
characterised in that the articulated joint arrangement (3) is provided in the form of a rubber bush (3").
3. Guide element as claimed in claim 1,
characterised in that the articulated joint arrangement (3) is provided in the form of a ball and socket joint (3'), optionally with a rubber bush.
4. Guide element as claimed in one of the preceding claims,
characterised in that the slip bearing ring(s) (4) is or are mounted inside a spherical layer-hollow body (3b) of the ball and socket joint (31) or an inner sleeve (3e) of the rubber bush (3").


5. Guide element as claimed in one of the preceding claims,
characterised in that the passage orifice (4d) in the slip bearing ring (4) is of a circular shape adapted to the cross-section of the guide track element (1).
6. Guide element as claimed in one of the preceding claims,
characterised in that several slip bearing rings (4) are disposed one above the other and are disposed so that they are able to slide to at least a slight degree in the spherical layer-hollow body (3b) or in the inner sleeve (3e) essentially perpendicular to the longitudinal axis of the guide track element (1) by means of their portion facing the guide track element (1).
7. Guide element as claimed in one of the preceding claims,
characterised in that the slip bearing ring (4) has an elastomer ring (4b), onto which is vulcanised a metal bush (4c) on the external face and a plastic slip ring (4a) on the internal face, which lies with its internal face on the guide track element (1).
8. Guide element as claimed in claim 7,
characterised in that the internal face of the plastic slip ring (4a) is of a rounded design.
9. Guide element as claimed in one of the preceding claims,
characterised in that at least one bellows (6) or similar is provided on the guide element (2) extending essentially along the guide track element (1), by means of which the gap between the guide element (2) and the guide track element (1) is screened against dirt across the total possible displacement path of the guide element (2) on the guide track element (1).


10. Guide element as claimed in claim 9,
characterised in that the bellows (6) is of a split design with a part (6a, 6b) disposed above the guide element (2) and underneath the guide element (2).




ABSTRACT
The invention relates to a guide element for a guide track element in a wheel suspension of a vehicle, one of which elements is essentially fixedly disposed on the body and the other element is essentially fixedly disposed on the wheel, and a slide bearing permitting a sliding movement of the guide element on the guide track element is disposed between these elements. The guide element is guided in a rotating movement and/or pivoting movement on the guide track element by means of an articulated joint arrangement, inside which is disposed at least one slip bearing ring, which is guided on the guide track element by its circular passage orifice adapted to the cross-section of the guide track element. This articulated joint arrangement may be provided in the form of a rubber bush or ball and socket joint. Several slip rings are preferably disposed one above the other in a so-called spherical layer-hollow body and are disposed so that they are able to slide slightly in the direction essentially perpendicular to the longitudinal axis of the guide track element by means of their portion facing the guide track element. This enables a guide track extending in a curve to be obtained. The slip ring preferably has an elastomer ring with a metal bush vulcanised onto the external face and a plastic slip ring vulcanised onto the internal face which lies with its internal face on the guide track element.
To,
The Controller of Patents,
The Patent Office,
Mumbai
Figure 1