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
ARTICULATED AND/OR BEARING ARRANGEMENT

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 : -

Description
The invention relates to a joint and/or bearing arrangement of the type outlined in the introductory part of claim 1 and a motor vehicle with one or more such joint and/or bearing arrangement(s), in particular in chassis and/or steering parts.
In the case of joint arrangements with a solid journal made from steel, for example, which has to be retained in wheel suspensions, transverse arms or similar supports with a mounting orifice made from a softer material, for example a cast iron or aluminium, it is difficult to obtain a stable and low-tolerance connection of the journal in the mounting orifice without causing excessive strain on the softer material. A known way of dealing with this is to press-fit a solid sleeve into the support. The disadvantage of this, however, is that high forces act on the material surrounding the mounting orifice during the press-fitting operation, which can cause the mounting orifice to widen and severely weaken the support due to the fact that there are often only a few millimetres of material here.
Another known option is to press a conical disc onto the journal. To this end, the journal has a section with parallel walls, onto which the conical disc is pressed so that a conical portion of the journal can be pre-tensioned with respect to an oblique surface of the conical disc by means of axial tension. The oblique abutment surface of the journal which plays an active role in transmitting force to the conical disc is very small and weakening occurs in the region where the conical journal portion merges into the axial portion of the journal, especially in the presence of bending stress.
The underlying objective of the invention is to improve the mounting of the journal in the mounting orifice.
This objective is achieved by the invention on the basis of a joint arrangement comprising the characterising features defined in claim 1 and a motor vehicle incorporating the characterising features defined in claim 14. Advantageous
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embodiments and improved features of the invention are defined in the other claims 2 to 13.
As a result of the invention, no weak point is imparted to the joint journal in the region where force is transmitted and it is also not necessary to press-fit a sleeve in the mounting orifice. The support surrounding the latter is therefore subjected to only a minimum amount of stress and may be made from very thin and relatively soft and lightweight material, including a cast light metal, for example. Accordingly, the annular body does not have to be pressed onto the journal.
However, the tapering region may have a pitch angle of 15° to 20° with respect to the axis of the journal, at least in a part of its axial extension, thereby also enabling a high axial pre-tensioning.
Nevertheless, it still is possible to press the annular body onto the journal or an intimate connection retained by friction can be achieved if the tapering region is graduated and is provided with an axially parallel, cylindrical portion or a portion with a lower pitch is provided in its direction remote from the journal end. As a result, the region of the journal supported on the annular body, in particular a conical disc, is still able to transmit a maximum amount of force to the conical disc but remains unaffected. A graduation on the side remote from the journal end can not be damaged as a result.
If the tapering region has a variable pitch decreasing towards the journal end, a particularly good support can be obtained which is protected from bending stress whilst simultaneously imparting a high axial pre-tensioning. The pitch may merge into a parallel-walled, cylindrical region, for example, adjoining the journal end without a bending point.
The requirements placed on the external contour of the open or closed annular body are only low. The latter does not have to be pressed into the support of the mounting
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orifice but instead may also be retained by adhesive or other measures, for example. As a result, various external shapes are possible for the external contour of the annular body. For example, its shape may also be parabolic, hyperbolic, conical or a sphere segment.
If the annular body is made from a material that is more or less as strong as the joint journal, the risk of plastic deformation in one of the two parts is reliably prevented. The forces and stresses which act can be uniformly distributed between them.
Given the axial pre-tensioning, such joint or bearing arrangements may be subjected to bending both axially and intensively due to the large surface area of the support.
To produce axial pre-tensioning, the journal may have a thread on the journal end, in which case it can be pre-tensioned in a defined manner by means of an appropriate nut.
A joint arrangement proposed by the invention may therefore be used on mountings of stronger parts which are subjected to high stress but are nevertheless optimised in terms of their weight, in mounting orifices of softer parts, for example within chassis and/ or steering parts of motor vehicles, for example for supporting parts of the wheel suspension.
Other advantages and features of the invention will become apparent from the drawings and examples of embodiments of the subject matter of the invention described below.
Of the drawings:
Fig. 1 is a schematic diagram showing an overall view of a joint and/or bearing arrangement proposed by the invention, with a journal mounted in a transverse arm and an upwardly pointing journal end,
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Fig. 2 is a detailed view, corresponding to detail II indicated in Fig. 1,
Fig. 3 is a view similar to that of Fig. 2 prior to mounting the bearing shell and seal and in addition having a graduation in the conically shaped journal portion on its side remote from the journal end,
Fig. 4 shows detail IV from Fig. 3,
Fig. 5 is a view similar to that of Fig. 3 but with a continuous pitch in the conical region of the journal and with a conical disc projecting beyond this portion towards the journal end,
Fig. 6 is a view similar to that of Fig. 5 but with a concave design of the portion supported in the conical disc,
Fig. 7 is a view similar to that of Fig. 6 but with a convex design of the portion supported in the conical disc,
Fig. 8 is a diagram similar to that of Fig. 2 but with a bigger pitch towards the journal end in the region merging with the narrower portion.
The joint arrangement 1 illustrated as a first example of an embodiment in Figures 1 and 2 comprises an axially extending and, in this instance, overall journal-type joint body 2, with a joint head 3 formed by a substantially spherically shaped piece for example. It may be mounted in a - usually slotted - bearing shell 4 so that it can move. An additional seal 5 may be provided for the contact region between the joint head 3 and joint shell 4 to prevent dirt getting in from outside and to accommodate a lubricant reservoir.
However, joint and/or bearing arrangements 1, 101, 201, 301, 401 of the type proposed by the invention may be of various different designs. In any event, in order
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to provide a connection between an orifice 6 in a relatively soft material and a stronger body 2, the joint and/or bearing body 2, 102, 202, 302, 402 is of a journal-shaped design, at least in certain regions, which can be fixedly mounted in a mounting orifice, in this instance a press-fit orifice 6 of a transverse arm 7. The transverse arm 7 is made from a relatively soft, cast aluminium, magnesium or iron or forged material and may have only a small amount of material around the orifice 6, for example with a thickness of only two to five millimetres, in order to keep the dimensions and weight of the unit as low as possible.
Such a joint arrangement 1,101, 201, 301,401 may be axially pressed in by means of a press-fit. The joint may be manufactured with diameter tolerances in the range of a few hundredths of a millimetre, as may the internal dimension of the orifice 6 of the body 7 accommodating it.
In order to obtain a firm support in the orifice 6, in particular of the chassis or steering part 7, the joint body 2 illustrated in Fig. 1 has at least one portion 8 which tapers in the direction of the journal end 9 disposed opposite the joint head 3. By means of this, the joint body 2 is indirectly supported with respect to the orifice 6. Since the joint body 2, which may be made from a chromium-molybdenum steel for example, may be made from a material that is significantly harder than that surrounding the orifice 6, an open or closed annular body 10, in particular a conical disc, is inserted between the latter and the orifice 6, and sits in contact with both the edge of the orifice 6 and the tapering portion 8. The annular body 10 is made from a material which is more or less as strong as that of the joint journal 2.
As may be seen from Fig. 5, the conical disc 10a may project in the direction of the journal end 9 beyond the region 8 supported against the conical disc 10a or, as illustrated in Fig. 1, may lie completely above its end 17 facing the journal end 9. In both cases, the supported conical region 8 sits in contact with the internal walls of the orifice 6 via the conical disc 10,10a only.
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A narrow and at least partially parallel and hence cylindrical or slightly tapering region 11 may adjoin the end 17 of the tapering portion 8 towards the journal end 9, the diameter of which is sufficiently small that it can extend through the orifice 6, even at its narrowest point, and opens into a thread 12 which co-operates with a nut 13 or another clamping element. The journal 2 may be axially pre-tensioned by means of this. Such a joint and/or bearing arrangement 1 is able to counteract both radial loads, such as in guide joints, and axial and radial loads, for example in supporting joints.
For high loads, it is necessary to provide as large as possible a contact surface between the tapering region 8 and the annular body 10.
To this end, it is proposed by the invention that a transition 14 be provided between the tapering portion 8 supported on the annular body and the thinner portion 11 adjoining the journal end 9 disposed outside of the axial extension of the annular body 10 in the direction of the journal end 9. As a result, the annular body 10 may sit with its internal face in full contact with the tapering portion 8 (see Fig. 2), thereby resulting in a large surface for transmitting force which is not weakened by a kink or similar transition 14 because this transition 14 lies outside the contact surface between the annular body 10 and supported, tapering portion 8 of the journal 2.
In the case of the joint arrangement 401 illustrated in Fig. 8, it is clear that a bigger pitch may also be provided at the transition 14 from the supported region 8 to the narrower region 11 of the journal 402, so that the region 11 does not have to taper less overall than the supported region 8.
In a part 8a, which in the first example of an embodiment illustrated in Figure 1 and Figure 2 takes up the entire axial extension of the region 8, the tapering region 8 supported on the annular body 10 in the mounted position has what in this instance is a uniform pitch angle with respect to the axis 15 of the journal 2 of 15° to 20°. The pitch of the region 8 therefore assumes a uniformly straight line in the first example
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of an embodiment, although this is not absolutely necessary, as will be explained in connection with other examples of embodiments.
The smaller the pitch angle of the region 8 is, the more possible it becomes to press on the annular body 10, which in this instance is a conical disc, without it being able to slide off the journal 2.
To this end, in the case of the joint arrangement 101 based on the second example of an embodiment illustrated in Figures 3 and 4, in order to obtain an intimate connection with the conical disc 110 retained by friction, the region 8 of the journal 102 supported on it is graduated 16 in a portion 8a axially clamped by the conical disc and has an axially parallel portion or portion 8b of a smaller pitch in its direction remote from the journal end 9. As a result, the region 8a of the journal 2 supported on the annular body 10, in particular a conical disc, is still able to effect a maximum transmission of force to the conical disc 10 whilst remaining unaffected. On the other hand, the annular body 10 can be pressed onto the region 8b. A graduation 16 at the end of the region 8 remote from the journal end 9 can be used to support the region 8a facing the journal end 9 without being damaged.
In addition or as an alternative to the graduation 16, the tapering region 8 may also have a variable pitch which decreases towards the journal end 9, as illustrated in Fig. 6, or a pitch which increases towards the journal end 9, as illustrated in Fig. 7.
In the case of the concave design of the joint or bearing arrangement 202 illustrated in Fig. 6, the region 8 may merge into the narrower region 11 adjoining the journal end 9 without any kink point or other weakening. The groove illustrated here is purely a result of the production method and also lies axially far outside the supported portion 8. The internal contour of the annular body 210 facing the external wall of the joint journal 202 is provided with a convex shape complementing the joint journal 202 adapted to the supported tapering region 8 of the joint journal 202.
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In the design illustrated in Fig. 7, the situation is precisely the reverse: in this instance, the journal 302 of the joint or bearing arrangement 301 is provided with a convex portion 8 and, accordingly, the internal wall of the annular body 310 is adapted to this, having a concave shape.
In any event, a pitch must be provided at least in a part-region of the portion 8 which is sufficiently large to enable an axial pre-tensioning to be obtained by means of the clamping element 13.
Accordingly, the shape of the portion 8 overall may be both hyperbolic and parabolic, with or without graduations, or may be of some other design, but in any event, a transition 14 at the journal end to the other, narrower portion 11 must he outside the supporting region 8 on the annular body 10,110, 210, 310.
The connection between the supporting region 8 and the annular body 10,110, 210, 310 may be of various designs and in addition to the press fit, it is also possible to opt for a bonded connection, for example. The connection may also be obtained by a seal 5 in the case of a loose abutment.
The external contour of the annular body 10, 10a, 110, 210, 310 facing the internal wall of the mounting orifice 6 may also be of different shapes, for example parabolic, hyperbolic or conical.
The annular body 10, 10a, 110, 210, 310 need not necessarily be of a rotationally symmetrical design with respect to the journal axis in all cases and instead, if the joint or bearing arrangement is subjected to bending stress in a preferred direction of force, for example is subjected to recurring bending in one plane only, it may also be elliptical or elongated in some other manner in order to counteract this stress. In this case, the journal 2, 102, 202, 302, 402 itself may also have a cross-section that is adapted to this, for example elliptical.
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It would be conceivable to opt for various designs for the external surfaces 18 of the conical disc 10, 10a, 110, 210, 310 which lie directly on the softer component 7, in which case, depending on requirements, an axial and radial support may be provided. In this respect, it is also practical to provide a large contact surface in order to avoid too high loads on the relatively soft component 7 locally and avoid the risk of plastic deformations.
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List of reference numbers
1 Joint or bearing arrangement (101; 201, 301, 401)
2 Joint or bearing body (102, 202, 302, 402)
3 Joint head
4 Joint shell
5 Seal
6 Press-fit orifice
7 Transverse arm
8 Tapering region
9 Journal end
10 Annular body (10a; 110; 210; 310)
11 Cylindrical region
12 Thread
13 Nut
14 Transition
15 Axis
16 Graduated edge
17 End of the region 8
18 External surface of the conical disc
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WE CLAIM:
1. Joint and/or bearing arrangement (1; 101; 201; 301; 401) comprising a joint or
bearing body with a joint journal (2; 102; 202; 302; 402), which can be fixedly
retained in a mounting orifice (6), for example a press-fit orifice of a
transverse arm (7), and to this end has at least one portion (8) tapering in the
direction of the journal end (9) to provide support in at least certain regions
on an annular body (10; 10a; 110; 210; 310), in particular a conical disc,
adjoined by a region (11) which is at least partially cylindrical or tapers less
than the portion (8) towards the journal end (9),
characterised in that the transition (14) between the tapering portion supported on the annular body (10; 10a; 110; 210; 310) and the portion (11) that is cylindrical or tapers less towards the journal end (9) is disposed outside the axial extension of the annular body (10; 10a; 110; 210; 310).
2. Joint and/or bearing arrangement as claimed in claim 1,
characterised in that the joint journal (2; 102; 202; 302; 402) is made from a stronger material than the material surrounding the mounting orifice (6).
3. Joint and/or bearing arrangement as claimed in one of claims 1 or 2, characterised in that the tapering region (8) has a pitch angle of 15° to 20° with respect to the axis (15) of the journal, at least in a part of its axial extension.
4. Joint and/or bearing arrangement as claimed in one of claims 1 to 3, characterised in that the tapering region (8) is graduated (16) and has a cylindrical portion or portion (8b) with a relatively smaller pitch in its direction remote from the journal end (9).
5. Joint and/or bearing arrangement as claimed in one of claims 1 to 4, characterised in that the tapering region (8) has a variable pitch which
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decreases or increases towards the journal end (9).
6. Bearing and/or joint arrangement as claimed in one of claims 1 to 5, characterised in that the supporting annular body (10; 10a; 110; 210; 310) sits in contact both with an internal wall of the mounting orifice (6) and an external wall of the joint journal (2; 102; 202; 302; 402).
7. Joint and/or bearing arrangement as claimed in claim 6,
characterised in that the external contour of the annular body (10; 10a; 110; 210; 310) facing the external wall of the joint journal (2; 102; 202; 302; 402) is essentially conical with a pitch angle complementing the joint journal (2; 102; 202; 302; 402) in its supported region (8) adapted to the supported tapering region (8) of the joint journal (2; 102; 202; 302; 402).
8. Joint and/or bearing arrangement as claimed in one of claims 6 or 7, characterised in that the internal contour of the annular body (10; 10a; 110; 210; 310) facing the joint journal (2; 102; 202; 302; 402) is of a parabolic, hyperbolic or conical shape.
9. Joint and/or bearing arrangement as claimed in one of claims 1 to 8, characterised in that the annular body (10; 10a; 110; 210; 310) is made from a material that is more or less of the same strength as that of the joint journal (2; 102; 202; 302; 402).
10. Joint and/or bearing arrangement as claimed in one of claims 1 to 9, characterised in that this joint and/or bearing arrangement can be subjected to both axial and radial bending stress.
11. Joint and/or bearing arrangement as claimed in one of claims 1 to 10, characterised in that the annular body (10; 10a; 110; 210; 310) has a longitudinal extension which deviates from a rotational symmetry in order to
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counteract a preferred direction of stress.
12. Joint and/or bearing arrangement as claimed in one of claims 1 to 11, characterised in that the mounting orifice (6) is cut out from a steering arm or support (7) made from cast material.
13. Joint and/or bearing arrangement as claimed in one of claims 1 to 12, characterised in that the journal (2; 102; 202; 302; 402) can be axially pre-tensioned via a thread (12) disposed at the journal end (9) and a clamping element (13).
14. Motor vehicle with at least one joint and/or bearing arrangement (1; 101; 201; 301) as claimed in one of claims 1 to 13, in particular in chassis and/or steering parts.
Dated this 25th day of October, 2007

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ABSTRACT
A joint and/or bearing arrangement (1; 101; 201; 301; 401) comprising a joint or bearing body with joint journal (2; 102; 202; 302; 402) which can be fixedly retained in a mounting orifice (6), for example a press-fit orifice, of a transverse arm (7), and to this end has at least one portion (8) tapering in the direction of the journal end (9) to provide support in at least certain regions on an annular body (10; 10a; 110; 210; 310), in particular a conical disc, adjoined by a parallel-walled region (11) that tapers less towards the journal end (9), is designed so that the transition (14) between the tapering portion supported on the annular body (10; 10a; 110; 210; 310) and the portion (11) that is cylindrical or tapers less towards the journal end (9) is disposed outside the axial extension of the annular body (10; 10a; 110; 210; 310).
To,
The Controller of Patents,
The Patent Office,
15
Mumbai