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 : BEARING ARRANGEMENT
2. APPLICANT(S)

a) Name : ZF FRIEDRICHSHAFEN AG
b) Nationality : GERMAN Company
c) Address : 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 bearing arrangement, in particular for the central joint of a Watt's linkage, of the type outlined in the introductory part of claim 1.
Bearing arrangements of the generic type are used as central joints in Watt’s linkages of the above-mentioned type for example, although not exclusively so. Watt's linkages are used in particular on rear axles of top-of-the-range motor vehicles. This being the case, the Watt's linkage links the wheel suspensions of the two rear wheels with one another and with the chassis or vehicle body so that one or both of the rear wheels is able to spring in a vertical movement unobstructed but lateral movements of the rear axle and rear wheels relative to the chassis are prevented or reduced, whilst other designs of the Watt's linkage also prevent or reduce rocking movements of the bodywork.
Bearing arrangements on the motor vehicle, especially bearing arrangements for central joints of this type, are subjected to constant forces and moments due to dynamic loads which occur when the motor vehicle is travelling, caused by centrifugal acceleration when driving round bends or due to highly dynamic springing movements on uneven road surfaces, for example. Since factors such as a cost-saving lightweight construction and reducing mounting space on the motor vehicle are assuming ever increasing importance, there is also a need for more compact designs and modular constructions in respect of bearing arrangements of this type, and this aspect has led to more exacting demands being placed on the already high requirements expected of bearing arrangements of this type.
Patent specification DE 40 36 050 Cl discloses a sliding bearing for chassis parts with an inner bush and an outer bush and the two bearing bushes have axial bearing surfaces on an axially outer end. To this end, the inner bush has a radial flange projection extending to one side on the axial end of the inner bush, which is in turn supported on the axial end face of the outer bush by means of a sliding surface. The
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sliding bearing known from this publication has a seal to protect it from dirt caused by environmental influences, which is of an integral design with a rubber body surrounding the entire bearing and extending round the two mutually adjoining flange projections of the bearing bushes.
Firstly, however, this known sliding bearing is necessarily non-symmetrical or designed in the form of two halves, as a result of which it must generally be fitted in an arrangement based on pairs disposed in mirror image. However, this basically leads to an undesirable axial clearance, which then has to be compensated by other appropriate features.
The specific reason why this is the case with this known bearing is that the axial bearing surfaces are provided by means of radial flange projections of an integral design with the co-operating bushes, as a result of which each of the bearing bushes can be fitted in a co-operating bearing orifice from one side only. Furthermore, the integral design of the seal with the rubber body surrounding the bearing specifically makes it more difficult to fit the seal so that there is no deformation on the one hand and, secondly, makes subsequent maintenance or replacement of the seal without having to dismantle the entire bearing impossible. Moreover, additional separate components such as anti-friction rings, are needed in order to provide the axial bearing in known sliding bearings of this type. Finally, due to its construction, this known sliding bearing has both a high axial and radial elasticity, but this is not desirable in specific applications of sliding bearings. The seal protecting against environmental influences is often also not good enough for known bearing arrangements of this type.
Against this background, the objective of the present invention is to propose a bearing arrangement which overcomes the problems known from the prior art. This being the case, the intention is to avoid having to split the bearing arrangement into two, thereby avoiding the problems associated with the axial clearance. Furthermore, the bearing arrangement should be produced and fitted as a modular
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construction, thus reducing associated production, assembly and maintenance costs. Finally, the bearing arrangement should have the lowest possible tolerances, provide outstanding sealing properties, have a high axial and optionally also radial stiffness, whilst being capable of withstanding a high load and having a long service life.
This objective is achieved on the basis of a bearing arrangement incorporating the characterising features defined in claim 1. Subject matter relating to preferred embodiments is defined in the dependent claims.
The bearing arrangement proposed by the present invention has, in a manner that is initially known per se, an inner bush and an outer bush, and the inner bush and outer bush are able to rotate relative to one another along a bearing surface common to the two bushes. In principle, the inner bush may also be a solid bearing bolt, in which case a hollow inner bush may be combined with an additional fixing bolt under the service conditions in question, especially if the bearing arrangement is used in a Watt's linkage, but also generally.
Likewise in a manner known per se, the bearing arrangement also has at least one seal arrangement extending round the terminal bearing gap between the inner bush and outer bush, which seals the bearing gap off from the surrounding environment. The seal arrangement in this instance comprises an elastic sealing element with static and dynamic sealing surfaces. This means that the seal arrangement or the elastic sealing element of the seal arrangement lies in a static abutting arrangement, especially in the region of the two bearing bushes, whilst in the region where it adjoins the other bearing bush, the sealing element forms a sliding seal.
However, the bearing arrangement proposed by the invention is distinctive due to the fact that the seal arrangement is provided in the form of a seal module which can be connected to the inner bush. This being the case, the seal module also has a running surface arrangement to provide an axial bearing for the outer bush relative to the inner bush.
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What this means, in other words, is that, firstly, the function of providing an axial bearing is afforded by the invention by the modular seal arrangement which can be connected to the inner bush and is therefore no longer assumed by a radial flange projection integrally joined to the inner bush, as is usually the case in the prior art. As a result, both the outer bush and the inner bush may be of an essentially cylindrical design, thereby enabling the entire bearing to be fitted in the bearing orifice end-to-end from one side, without having to split the bearing bushes into halves.
Furthermore, the fact that the seal arrangement and running surface arrangement are integrated enables the bearing arrangement and its seal to be produced on the basis of a totally modular construction. In particular, this means that the complete seal arrangement, including the axial bearing, manufactured as a separate component in a modular design and to a high degree of precision, can be fitted and, if necessary, replaced as a module. When replacing the seal arrangement, therefore, it is no longer necessary to dismantle the entire bearing, as is usually the case in the prior art.
In addition, because the sealing and axial bearing functions of the bearing arrangement proposed by the invention are separate, the desired axial stiffness or axial bearing precision can be set as desired or provided by structural means. This makes it possible to achieve a particularly high axial stiffness and bearing accuracy, which, moreover, can be adjusted irrespective of any radial flexibility of the bearing arrangement. This also results in a particularly efficient seal against foreign media and environmental influences.
Finally, the fact that the sealing and axial bearing functions are separate enables the seal to be fitted irrespective of the stage of assembly of the bearing bushes, in particular after the bearing outer bush has been fitted or assembled with adjoining components, for example, which reduces stress on the seal caused by fitting and also reduces the risk of incorrect fitting and the associated detrimental effects on service
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life.
In applications where the bearing arrangement is used in a Watt's linkage, the structural design proposed by the invention results in an exact but smooth response behaviour of the central joint and Watt's linkage and thus helps to improve driving comfort and driving safety.
The specific construction and the materials used for the bearing arrangement proposed by the invention, in particular for the seal module, are not even essential to the invention, provided they are capable of meeting the intended service life requirements of the bearing and seal. In a preferred embodiment of the invention, however, the seal module has a support element, and the running surface arrangement and the support element are made from different materials. In other words, this means that the running surface arrangement may specifically be made from a material which is optimised in terms of sliding properties and in terms of resistance to wear.
For the purpose of the invention, the design or disposition of the static and dynamic sealing surfaces of the seal module are not crucial, provided the bearing gap is protected for the intended application. For example, it would be conceivable to provide separate components for the static and dynamic sealing surfaces, in which case each is joined to the support element of the seal module. In a preferred embodiment of the invention, however, the elastic sealing element is of an integral design, which means that one and the same elastic sealing element is provided with static and dynamic sealing surfaces. By preference, the static seal comprises an annular sealing collar disposed between the seal module and bearing block.
The nature of the connection between the running surface arrangement and the seal module and support element of the seal module is likewise not crucial to the invention. However, in another, likewise preferred embodiment of the invention, the running surface arrangement extends round or behind the support element forming
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a positive connection. This is of particular advantage if a particularly wear-resistant polymer material with a particularly low coefficient of sliding friction is used for the running surface arrangement, which, as experience has shown, can not be readily joined or adhered to other materials. In such a situation, the positive fit of the running surface system behind or around the support element ensures that the running surface arrangement can not work loose from the support element or effect any uncontrolled relative movements if the material of the running surface arrangement is not adhered to the material of the support element.
The seal module and support element may likewise be joined to the inner bush of the bearing arrangement in any manner for the purpose of the invention, provided the forces needed for the respective bearing can be transmitted, in particular axial forces. In a preferred embodiment of the invention, however, the seal module and the support element of the seal module are shrink-fitted or press-fitted onto the axial end of the inner bush. Accordingly, the shrink-fitting or press-fitting operation may take place in the region of a collar or radial shoulder in the end region of the bearing inner bush for example. This results in a connection between the bearing bush and seal module respectively support element which is firm but can be produced rationally and hence inexpensively.
In another, likewise preferred embodiment of the invention, the outer bush has a supporting ring with an axial thrust plane. This being the case, the supporting ring is preferably shrink-fitted or press-fitted onto the outer bush and specifically serves as a thrust plane or thrust surface for the dynamic sealing surface of the seal module.
In another preferred embodiment, both the dynamic sealing surface of the seal module and the sliding surface of the running surface arrangement are positioned in abutment with the thrust surface or one and the same thrust plane of the supporting ring. This is of advantage because it enables a simple design to be used for the supporting ring. The supporting ring therefore merely has to be provided with a single thrust plane, which is easy and inexpensive to produce, but which, due to its
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simple design and disposition, can be easily produced to a high quality and extremely high precision.
In an alternative embodiment of the invention, however, the dynamic sealing surface may also have a separate thrust surface in the region of the supporting ring or directly on the outer bush. To this end, the dynamic seal, which extends fully around the end face of the outer bush, may specifically be mounted in abutment with an outer periphery of the outer bush. Not only is this embodiment particularly compact, it also enables the bearing arrangement comprising inner bush, outer bush and seal module to be pre-assembled, in which case the constituent parts of the bearing pre-assembled in this manner can be temporarily held together by fitting the elastic sealing element which then sits around the bearing bushes in the manner of a bellows.
The design and material of the bearing surfaces of the inner bush and outer bush which slide on one another are likewise not essential to the invention. For example, the inner bush and outer bush may be positioned in abutment with one another or slide on one another directly along a cylindrical bearing surface. In a preferred embodiment of the invention, however, the bearing surface of the inner bush is formed by an additional bearing element made from polymer. Accordingly, it is particularly preferable for the bearing element to be provided in the form of a plastic material sprayed around the inner bush, in particular a thermoplastic polyurethane.
Thermoplastic polyurethanes are of advantage because of their special material properties. Thermoplastic polyurethanes are distinctive in particular due to a high degree of toughness and a certain amount of flexibility, as well as an extremely high resistance to abrasion and good vibration damping capacity, whilst being particularly resistant to media at the same time.
In another preferred embodiment of the invention, the plastic bearing element has at least one additional dynamic seal between the inner bush and outer bush to protect
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the bearing surface. This additional dynamic seal may be provided in the form of annular sealing lips, for example, extending in the region of the axially outer lying ends of the bearing arrangement between the surfaces of the inner bush and outer bush.
In another preferred embodiment of the invention, the static seal may comprise an annular seal axially disposed between the bearing element and seal module respectively support element. This static annular seal prevents any dirt existing in or penetrating the region of the press-fit connection between the support element and inner bush from getting into the region of the bearing surface between the inner bush and outer bush.
In another, particularly preferred embodiment of the invention, the seal module has an additional spray guard, preferably in the radially outer region of the seal module and the elastic sealing element. This additional spray guard may specifically be provided in the form a contactless sealing gap or a type of labyrinth seal and thus constitutes a first barrier to dirt, moisture and other potentially harmful environmental media. The additional spray guard also screens the sliding dynamic sealing surface of the seal module from the water jet of high-pressure washers commonly in use these days, for example. The additional spray guard is preferably of an integral design with the elastic sealing element.
In principle, any material may be used for the elastic sealing element, provided it satisfies the requisite sealing properties and service life requirements. By particular preference, however, the elastic sealing element is made from nitrile-butadiene rubber, which has proved to be particularly suitable for sealing applications of this type due to its resistance to a whole range of different media and its advantageous mechanical properties.
Overall, in order to implement the invention, it is not inquired that the bearing arrangement is necessarily of a symmetrical design and/or that the two ends of the
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inner bush and outer bush are of an identical design or have the same seal module, because non-symmetrical or only one-sided bearing arrangements would be conceivable and could be used in principle. Particularly if the bearing arrangement is to be used with a Watt's linkage, however, it is preferable if the bearing arrangement has a seal module and/or a supporting ring at each of the two axial ends. As a result of the modular construction of the bearing arrangement made possible by the invention, one option in this respect is to provide identical seal modules and supporting rings at both ends of the bearing.
The invention will be explained in more detail below with reference to what are
merely examples of embodiments illustrated in the appended drawings. Of these:
Fig.l is a schematic perspective diagram of a central joint for a Watt's
linkage of a motor vehicle axle;
Fig. 2 is a schematic diagram in section showing the central joint illustrated
in Fig. 1 with a first embodiment of a bearing arrangement proposed
by the invention, viewed in section through the joint axis;
Fig. 3 is a diagram in section, broken open, showing a detail from Fig. 2
denoted by "A" in Fig. 2 on a larger scale;
Fig. 4 is a diagram corresponding to Fig. 3 illustrating the detail of Fig. 3
showing a section in a different plane;
Fig. 5 is a diagram corresponding to that of Fig. 2 illustrating a central joint of
the type illustrated in Fig. 1 with another embodiment of the bearing
arrangement proposed by the invention;
Fig. 6 . is a diagram corresponding to that of Figs. 3 and 4 showing a detail
from Fig. 5 denoted by "B" in Fig. 5 on a larger scale; and
Fig. 7 is a diagram corresponding to that of Figs. 3, 4 and 6 showing the
detail from Fig. 6 in section through a different plane.
Fig. 1, firstly, is a schematic diagram illustrating the construction of a central joint 1
for a Watt’s linkage of a motor vehicle axle.
As may be seen first of all, there are two sheet metal components 2, 3 forming the
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housing or bearing block of the central joint 1. The rocker or coupler 6 of the Watt’ s linkage, which is only partially visible in Fig. 1, is connected to the rotatable outer bush 5 of a bearing arrangement 4 which is disposed behind the coupler 6 in the diagram shown in Fig. 1 and therefore covered. The purpose of the two sleeve joints 7 of the coupler 6, of which only one sleeve joint 7 is partially visible in Fig. 1, is to link and provide a kinematic coupling for the radius rods (not illustrated) of the Watt's linkage.
As may be seen from Fig. 1, the central joint 1 is of an extremely compact construction, thereby saving on space and weight, but produces correspondingly higher forces and torques in the region of the bushes and the bearing 4 of the central joint 1 due to the short lever arms of the coupler 6.
All the components of the central joint 1, in particular the bearing 4, must therefore be capable of meeting the most stringent demands with regard to load-bearing capacity, fail-safe operation and service life. This is even more important in the case of this embodiment of the bearing arrangement proposed by the invention when used in this application because a Watt's linkage constitutes an elementary component unit with regard to the driving stability of the vehicle, failure of which can crucially impair control of the vehicle and must therefore be avoided under all circumstances.
Fig. 2 illustrates the central joint 1 shown in Fig. 1, viewed in section through the joint axis. As may be seen, the housing components or bearing blocks 2, 3 are also shown here. Fig. 2 also illustrates the design of the bearing 4 of the central joint 1 with the outer bush 5 bearing the coupler 6 and the stop buffer 8 for restricting the rotating motion of the bearing 4 and coupler 6. Also illustrated is one of the two sleeve joints 7 disposed on the coupler 6, located to the rear of the plane of the drawing in Fig. 2.
The bearing 4 of the coupler 6 of the Watt’s linkage essentially comprises the inner
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bush 10 rigidly secured in the housing or in the bearing blocks 2, 3 by means of the bolt 9 to prevent rotation, the outer bush 5 bearing the coupler 6 and an additional bearing element 11 made from plastic disposed between the inner bush 10 and outer bush 5. The bearing additionally has a seal arrangement or a seal module 12 on each of the two axial bearing ends.
A more detailed illustration of the design of the seal arrangement or seal module 12 is shown in Fig. 3 and Fig. 4. The detail illustrated on a larger scale in Figs. 3 and 4 corresponds to the region denoted by the letter "A" in Fig. 2. This diagram in section is broken open and thus shows the inner bush 10, which is only partially visible, as well as the outer bush 5 of the bearing 4, which is likewise only partially visible for the same reason. In the embodiment illustrated as an example, the surfaces of the inner bush 10 and outer bush 5 do not slide directly on one another. Instead, the inner bush 10, which may also be made from aluminium specifically for this purpose, is provided with an additional bearing element 11 made from a thermoplastic polyurethane sprayed round it, on the radially outer surface of which the outer bush is rotatably mounted.
Fig. 3 and Fig. 4 also show the seal arrangement or seal module 12 of the bearing arrangement 4 proposed by the invention. The seal module 12 comprises the annular support element 13, the elastic sealing element 14 and running surface arrangement 15, 16, 17 or running surface 15. As illustrated, the support element 13 is pressed onto the inner bush 10 in the region of a cylindrical shoulder and both the running surface 15 as well as the elastic sealing element 14 are respectively provided in the form of an appropriate polymer material sprayed around the support element 13. Accordingly, the sprayed region 15, 16, 17 constituting the running surface 15 extends round the support element 13 in a row of axial recesses 16, as may be seen by comparing Figs. 3 and 4. Figs. 3 and 4 differ from one another solely in terms of the angle of the sectional plane through the axis of the central joint 1 and bearing arrangement 4. In order to guarantee a reliable positive join between the running surface 15 and
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support element 13, the sprayed recesses 16 are also joined to the rear face of the support element 13 lying opposite the running surface 15 by means of a web 17, as may be seen from the section illustrated in the diagram of Fig. 3. As a result, it is also
possible to use materials for the running surface 14 which have only a slight or absolutely no tendency to adhere to the material of the support element 13. Known bearing materials of the PTFE type may be used for this purpose, although these are merely examples.
In the embodiment illustrated, the sprayed region of the support element 13 constituting the elastic sealing element 14 essentially has three functional projections or lips 18, 19, 20. These include the dynamic or sliding sealing surface 18, which slides on the supporting ring 21 connected to the outer bush 5, and the static sealing surface 19 disposed on the rear face of the support element 13, which affords the seal with respect to the housing shells or bearing blocks 2, 3 of the central joint 1 (not illustrated), shown in Fig. 2. The elastic sealing element 14 also has another sealing lip 20 disposed on its external periphery, forming an additional spray guard 20 for the sliding seal surface 18 lying further inwards, which is subjected to a high degree of stress.
At its upper radial plane by reference to the drawing, the supporting ring 21 press-fitted on the outer bush 5 forms the thrust surface 22 both for the sliding or dynamic seal 18 of the elastic sealing element 14 and for the running surface 15, which forms the largely rigid axial bearing for the outer bush 5 relative to the inner bush 10. The advantage of the separate supporting ring 21 provided separately from the outer bush 5 is that it may be made from a different material from that of the outer bush 5 itself, in which case this material may be adapted so that it optimally suits the demands placed on the sliding seal 18 and axial bearing 15. This arrangement also facilitates assembly of the central joint 1 and enables better bearing tolerances to be obtained, given that the supporting rings 21 for the bearing arrangement 4 are not
fitted until after the outer bush 5 has been welded and the coupler 6 welded onto the outer bush 5, for example.
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In the region disposed axially between the bearing element 11 and seal module 12 respectively support element 13, another static seal 23 is provided, as illustrated in the diagram of Figs. 3 and 4 - and also in the case of another embodiment illustrated as an example in Figs. 5 to 7. The static seal 23 may be provided in the form of an annular sealing element 23 disposed between the bearing element 11 and support
element 13. However, it may also be provided in the form of an annular shoulder 23
integrally formed on the bearing element 11 itself, which is press-fitted on the support element 13 when the bearing arrangement 4 is assembled.
The static seal 23 prevents any dirt which might have penetrated the region of the press-fit connection between the support element 13 and inner bush 10 from getting
into the region of the bearing surface between the inner bush 10 respectively bearing element 11 and the outer bush 5. Additional sliding sealing lips 24, which may be integrally formed with the bearing element 11 in particular, likewise protect the bearing surface between the inner bush 10 respectively bearing element 11 and the outer bush 5.
Fig. 5 depicts a diagram in section corresponding to that of Fig. 2, showing a central joint with another embodiment of the bearing arrangement 4 proposed by the invention, whilst Figs. 6 and 7 provide diagrams in section, broken open, showing the detail denoted by the letter "B" in Fig. 5 on a larger scale.
The embodiment illustrated in Figs. 5 to 7 primarily differs from the embodiment illustrated in Figs. 2 to 4 due to the design and disposition of the elastic sealing element 14 and due to the absence of the supporting ring 21 used with the embodiment shown in Figs. 2 to 4.
Instead of the supporting ring 21, the end face 25 of the outer bush 5 itself constitutes the thrust surface 25 of the running surface 15 of the seal module 12 in the embodiment illustrated in Figs. 5 to 7. The seal module 12 itself in turn comprises an
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annular support element 13, a running surface 15 sprayed around the support element 13 and extending through recesses 16 and webs 17, and an elastic sealing element 14. The sealing element 14 is in turn fixedly joined to the support element 13 in the region of the static sealing surface 19 and forms the dynamic sealing surface 18 sliding in an annular groove 26 on the external face of the outer bush.
During assembly of the bearing arrangement 4 and the central joint 1 illustrated in Fig. 5 respectively Fig. 2, a lip forming the static seal 19 is respectively pressed onto the sheet metal housing shells or bearing blocks 2,3 of the central joint 1 and is thus additionally secured relative to the bearing blocks 2, 3 and to the stationary inner bush 10. All in all, the bearing 4 for the coupler 6 of the central joint 1 is therefore completely encapsulated as a result, thereby affording reliable protection for this component, which is subjected to a high degree of stress.
As a result, it is clear that the invention specifically enables the bearing arrangement, for example for the central joint of a Watt's linkage, and its seal to be constructed in a totally modular design, offering the associated advantages with regard to production, warehousing, fitting and maintenance of the bearing arrangement. As a result of the invention, it is also possible to use continuous non-split bearing bushes, which also assists fitting as well as increasing the load-bearing capacity and service life of the bearing arrangement proposed by the invention compared with those known from the prior art. The bearing arrangement proposed by the invention also provides a particularly good seal against environmental influences and a precise and smooth response behaviour. Finally, the axial as well as the radial stiffness of the bearing arrangement can be dimensioned separately from one another as a result of the invention, which offers decisive advantages with regard to points of the bearing subjected to high stress, such as the compact central joint discussed here.
The invention therefore makes a significant contribution to the economical
production of highly resistant bearing arrangements for Watt's linkages, stabilisers, wheel suspensions and such like.
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List of reference numbers
1 Central joint
2 Bearing block
3 Bearing block
4 Bearing region, bearing arrangement
5 Outer bush
6 Coupler
7 Sleeve joint
8 Stop buffer
9 Bolt
10 Inner bush
11 Bearing element
12 Seal module
13 Support element
14 Elastic sealing element
15 Running surface arrangement, running surface, axial bearing
16 Running surface arrangement, axial recess
17 Running surface arrangement, web
18 Sliding/dynamic sealing surface
19 Static sealing surface, sealing collar
20 Spray guard
21 Supporting ring
22 Thrust plane, thrust surface
23 Static sealing surface, annular seal

24 Additional dynamic seal
25 Thrust surface
26 External periphery, annular groove
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CLAIM:
1. Bearing arrangement (4), in particular for the central joint (1) of Watt's
linkage, which bearing arrangement (4) has an inner bush (10) and an outer
bush (5), and the inner bush (10) and outer bush (5) are able to move in
rotation relative to one another by means of a common bearing surface, and
the bearing arrangement (4) also has at least one seal arrangement (12)
extending around the terminal bearing gap between the inner bush (10) and
outer bush (5) and providing a seal against the surrounding environment,
which seal arrangement (12) comprises an elastic sealing element (14) with
static and dynamic sealing surfaces,
characterised in that the seal arrangement (12) is provided in the form of a seal module (12) which can be connected to the inner bush (10), and the seal module (12) has a running surface arrangement (15) providing an axial bearing for the outer bush (5).
2. Bearing arrangement (4) as claimed in claim 1,
characterised in that the seal module (12) has a support element (13) and the running surface arrangement (15) and support element (13) are made from different materials.
3. Bearing arrangement (4) as claimed in claim 1 or 2,
characterised in that the elastic sealing element (14) is of an integral design.
4. Bearing arrangement (4) as claimed in one of claims 1 to 3, characterised in that the static seal comprises a sealing collar (19) disposed between the seal module (12) and bearing block (2,3).
5. Bearing arrangement (4) as claimed in one of claims 2 to 4, characterised in that the running surface arrangement (15) fits positively behind the support element (13).
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Bearing arrangement (4) as claimed in one of claims 1 to 5,
characterised in that the seal module (12) is shrink-fitted or press-fitted onto
the axial end of the inner bush (10).
Bearing arrangement (4) as claimed in one of claims 1 to 6,
characterised in that the outer bush (5) has a supporting ring (21) with an
axial thrust plane (22).
Bearing arrangement (4) as claimed in claim 7,
characterised in that the supporting ring (21) is shrink-fitted or press-fitted
onto the axial end of the outer bush (5).
Bearing arrangement (4) as claimed in claim 7 or 8,
characterised in that the dynamic sealing surface (18) and running surface
arrangement (15) are positioned in abutment with the thrust plane (22).
Bearing arrangement (4) as claimed in one of claims 1 to 6,
characterised in that the dynamic sealing surface (18) extending round the
end face of the outer bush (5) is positioned in abutment with an external
periphery (26) of the outer bush (5).
Bearing arrangement (4) as claimed in one of claims 1 to 10,
characterised in that the bearing surface on the inner bush side is provided in
the form of a bearing element (11) made from polymer.
Bearing arrangement (4) as claimed in claim 11,
characterised in that the bearing element (11) is provided in the form of
plastic material sprayed around the inner bush (10).
Bearing arrangement (4) as claimed in claim 11 or 12,
characterised in that the bearing element (11) is made from a thermoplastic
polyurethane (TPU).
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14. Bearing arrangement (4) as claimed in one of claims 11 to 13, characterised in that the bearing element (11) has at least one additional dynamic seal (24) to protect the bearing surface.
15. Bearing arrangement (4) as claimed in one of claims 11 to 14, characterised in that the static seal comprises an annular seal (23) disposed between the bearing element (11) and seal module (12).
16. Bearing arrangement (4) as claimed in one of claims 1 to 15, characterised in that the seal module (12) has an additional spray guard (20).
17. Bearing arrangement (4) as claimed in claim 16,
characterised in that the additional spray guard (20) is formed integrally with the elastic sealing element (14).
18. Bearing arrangement (4) as claimed in one of claims 1 to 17, characterised in that the elastic sealing element (14) is made from nitrile-butadiene rubber (NBR).
19. Bearing arrangement (4) as claimed in one of claims 1 to 18, characterised in that the bearing arrangement (4) respectively has a seal
module (12) at the two ends of the inner bush (10) respectively outer bush (5)
and/or a supporting ring (21).
Dated this 31st day of January, 2007

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Abstract
The invention relates to a bearing arrangement 4 with a bearing inner bush 10 and outer bush 5, in particular for the central joint 1 of a Watt's linkage. The bearing arrangement 4 is provided with a seal arrangement 12 extending around the terminal bearing gap between the inner bush 10 and outer bush 5. The seal arrangement 12 comprises an elastic sealing element 14 with static and dynamic sealing surfaces.
The bearing arrangement 4 is characterised in that the seal arrangement 12 is provided in the form of a seal module 12 which can be connected to the bearing inner bush 10, and the seal module 12 also has a running surface 15 providing an axial bearing for the outer bush 5.
The invention specifically enables a bush bearing of modular construction, capable withstanding a high amount of stress, to be produced economically. Furthermore, it is also possible to use non-split, continuous bearing bushes, which improves the ease of assembly, precision and service life of the bearing arrangement. Particularly in the case of bush bearings subjected to a high degree of stress, the axial and the radial stiffness of the bearing arrangement can be dimensioned independently of one another and a particularly good seal can be obtained against environmental influences.
To
The Controller of Patents
The Patent Office
Mumbai
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