Title of Invention

BEARING SHELL

Abstract

The invention present a bearing shell of plastics material for a ball-and-socket joint for mounting a ball-and-socket joint pin which is held in a rotatable and pivotable manner in the bearing shell, with at least two shell parts 1a, 1b forming an. internal bearing face shaped in the form of a hollow sphere, wherein the shell parts form, as a whole, a bearing ring 1 with a respective opening 2, 3 disposed at the opposite front sides of the bearing ring, and wherein at least one web 4 which connects the shell parts 1a, 1b is disposed transversely over one of the opening cross sections.

Full Text

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 SHELL 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 bearing shell of plastics material for a ball-and-socket joint for mounting a ball-and-socket joint pin which is held in a rotatable and pivotable manner in the bearing shell. Ball-and-socket joints are used in many areas of mechanical engineering and in particular in the motor vehicle industry as a component of chassis and steering assemblies. In this respect the bearing shells located in the ball-and-socket joints surround a so-called ball head as a component part of a ball-and-socket joint pin and are in turn held in a ball-and-socket joint housing. The ball-and-socket joint pin and housing are on the one hand disposed on the chassis or steering side and on the other fixed to the body, so that the two components can move relative to one another within certain defined degrees of freedom. A general problem when assembling the ball-and-socket joints in this respect lies in the fact that, in order to securely retain the ball pin, the bearing shell must surround the ball head located on the pin by more than one half so as to prevent unintentional separation of the bearing shell and the ball pin. Because the ball pin is enclosed by more than one half by the bearing shell, it is not possible to easily put the two components together. It is instead necessary to employ a special structural and/or material design to form the bearing shell such that it can be slipped over the ball head during the assembly process and, on account of its resilient properties or other structural specifications, can be fixed in conjunction with the subsequent installation of the bearing shell in the ball-and-socket joint housing. Two different design variants are known from DE 199 58 149 Al, for example, for solving the problem. On the one hand the bearing shell may be provided with a plurality of longitudinal slots. The actual bearing shell is then constructed such that it essentially comprises a -2- recess shaped in the form of a hollow sphere for holding the ball head of the ball-and-socket joint pin. This is pressed into this recess through an insertion opening which is provided, with the slotted form of the bearing shell enabling the region provided with the opening to stretch outwards to an extent such that the ball pin can be inserted. *' Another assembly variant is obtained according to the above-mentioned publication through the bearing shell consisting of two shell parts which together form an internal bearing face shaped in the form of a hollow sphere and are connected together by means of a so-called film hinge and can therefore be opened up for assembly on the ball-and-socket joint pin. After being placed in position, the two shell parts are closed and in turn inserted in the ball-and-socket joint housing. Both structural variants have proved entirely successful for certain purposes. However the first-mentioned embodiment, in which the bearing shell is provided with longitudinal slots, entails the problem of the ball-and-socket joints which are used generally being subject to a main loading direction in the installed state. The forces which occur in the main loading direction give rise to high surface pressures within the bearing shell, while the slots in the bearing shell required for assembly have an adverse effect, as the plastics material is weakened and the remaining bearing face portions are accordingly highly stressed. Under unfavourable operating conditions this may result in the plastics material of the bearing shell being subjected to a creep or flow movement, which means that the slots diminish irreversibly, leading to a reduction or termination of the preloading which is necessary for absence of play in the ball-and-socket joint. In order to prevent disadvantages of this kind, the above-mentioned second design variant is used for certain purposes in that a film hinge connects two shell parts together and enables the bearing shell to be opened up for assembly purposes. -3- However this entails the disadvantage of only being able to use highly extensible plastics materials for bearing shells of this kind, as the material must be able to extend by up to 50% for the film hinge to function. Plastics materials such as polypropylene or polyethylene are therefore as a rule used for bearing shells of this kind. On the other hand these materials do not have a sufficient load bearing capacity for certain uses of ball-and-socket joints, so that the overall size of the ball-and-socket joint may have to be increased to support the forces which occur. Taking the problems described above and the prior solution possibilities known from the prior art which are focussed thereon as a starting point, the object of the invention is to configure a bearing shell for a ball-and-socket joint such that on the one hand even high forces in one loading direction can be supported without problems and on the other the bearing shell can be easily produced in terms of construction and assembly and easily handled. This object is achieved according to the invention by means of the technical teaching which is defined by the features of Claim 1. An essential feature of the invention in this respect is that the bearing shell of plastics material for a ball-and-socket joint for mounting a ball-and-socket joint pin Which is held in a rotatable and pivotable manner in the bearing shell consists of at least two shell parts. These form together, i.e. when the bearing shell is inserted in the ball-and-socket joint housing, a self-contained, internal bearing face shaped in the form of a hollow sphere, the shell parts forming, as a whole, a bearing ring with a respective opening disposed at the opposite front sides of the bearing ring, and at least one web which connects the shell parts being disposed transversely over one of the opening cross sections. This novel formation enables the two shell parts to be bent apart in a defined manner by means of the web which connects them without the plastics material which is -4- used having to be specially extensible. Because there is no extensibility requirement, it is also possible to use high-strength and therefore relatively brittle plastics materials, so that even maximum stresses can be supported and transmitted by means of small ball-and-socket joint variants. In this respect the web which connects the shell parts advantageously consists of a resilient plastics material, so that the shell parts come to lie following their assembly in the joint housing or at the joint ball in a defined position for the further assembly steps. Special developments of the teaching according to the invention are additionally comprised in the features of the subclaims. In one special development the web which connects the shell parts has a substantially semicircular arch shape over the opening cross section of the bearing ring. According to one special development, the overall structural dimensions of the bearing shell can be limited by giving the web a substantially rectangular cross section, with the larger side dimension of the cross section being disposed towards the opening cross section of the bearing ring. The smaller side dimension of the web cross section may correspond substantially to the thickness of the bearing ring. On the one hand this measure ensures that the shell halves will open out sufficiently, and on the other the uniform thickness of the web prevents buckling and the resultant overextension of the plastics material, as occur in the case of film hinges, for example. In addition to the presented features, at least one projection may also be disposed at the bearing shell at the outer edges of the bearing ring as an anti-twist element. This projection engages in a corresponding recess of an associated ball-and-socket joint housing holding the bearing shell and prevents relative movement between the ball-and-socket joint housing and the bearing shell. -5- In addition, in an expedient development of the subject matter of the invention the bearing ring and the web consist of plastics materials of different extensibility. For example, the bearing ring, as a functional element for supporting the necessary forces, may be considerably less extensible than the plastics material of the web. Through an appropriate choice of material, in conjunction with the structural formation of the web, the mobility of the half-shells relative to one another is increased without the possibility of overextension occurring, as in the case of film hinges. The different material compositions of the bearing ring and the web can in this case be achieved, for example, through a coinjection process or by means of two- component processes. It has also proved to be of advantage to form the bearing ring and optionally the web from PEEK material with carbon fibres. This special material can only extend by approximately 2% and is therefore most suitable for supporting high surface pressures. It is in addition possible to embed fibre reinforcements, for example of carbon fibres or glass fibres, in the plastics material, which additionally increases the load bearing capacity of the bearing shell and therefore of the ball-and-socket joint. Furthermore, in a further expedient development of the subject matter of the invention a narrow intermediate gap is disposed between the shell parts of the bearing ring when the bearing shell is in the assembled state. This narrow intermediate gap serves to accommodate thermal expansions which may occur as a result of an increased thermal load on the shell parts of the bearing shell. Two embodiments of the subject matter of the invention are illustrated in detail in the following on the basis of the accompanying drawings. Here Figures 1 and 2 are perspective representations of the bearing shell according to the invention. -6- It can be seen here that the bearing shell essentially consists of a bearing ring 1 which comprises an internal hollow spherical segmental region. A respective opening 2 and 3 is located at the top side and the underside of the bearing ring. The opening 3 is spanned by a web 4 in the represented embodiment. The figure also shows that the bearing ring, which is marked as a whole by 1 and forms the bearing shell, consists of two shell parts la and lb. The two together form ori their inside the bearing surface, of a hollow spherical shape, for a ball head, which is to be held therein, of a ball-and-socket joint pin, this not being a subject matter of the invention and therefore not being represented. The web 4 connects the shell parts la and lb together and enables the shell parts la and lb to move slightly relative to one another, so that the bearing shell can be slipped over or snapped over the ball head of a ball-and-socket joint pin. The figure also shows that two projections 5, 6 are located diametrically opposite one another at the outer contour of the bearing ring 1, these engaging in corresponding recesses of a ball-and-socket joint housing surrounding the bearing shell and therefore reliably preventing a relative movement between the bearing shell and the ball-and-socket joint housing. Twisting can alternatively also be prevented by embedding the web 4 in a corresponding recess of a joint housing which holds the bearing shell and has an accompanying cover. As represented in the figure, the web 4 has a rectangular cross section, with the larger side dimension of the cross section being disposed parallel to the opening cross section of the opening 3 of the bearing ring 1. The smaller side dimension of the web cross section makes it easier for the web to bend as a result of the shell parts la and lb being pushed apart. -7- The web 4 and the bearing ring 1 may be composed of different materials through a special coinjection process or multi-component injection moulding process, for example, so that the plastics material of the web can be more extensible than the bearing ring 1, which is provided for supporting and transmitting forces. The plastics materials which are used can additionally be improved in terms of their useful properties by fibre reinforcements. It can also be seen from the figure that a narrow intermediate gap 7 remains between the shell parts la and lb when the bearing shell is in the represented installed state. This gap serves to accommodate thermal expansions to which the shell parts la and lb may be subject as a result of a high thermal load. The illustrated structural novel formation of the bearing shell according to the invention provides in particular the advantage of a high load bearing capacity of the bearing shell as a result of the possibility of using a heavy-duty plastics material with minimum extensibility being accompanied by the possibility of easily assembling the bearing shell by easily pushing the shell parts la and lb apart and then pushing the bearing shell over the ball head of a ball-and-socket joint pin by way of the opening 2 of the bearing ring 1. Figure 2 depicts a further development variant of the bearing shell according to the invention which differs from the embodiment of Figure 1 in particular in terms of its outer contour. Essential elements of the invention such as the web 4, the bearing ring 1 with the shell parts la and lb as well as the openings 2 and 3 adjoining the bearing ring 1 correspond in terms of their features to the first embodiment discussed in detail with reference to Figure 1. Differences lie in the outer contour of the bearing ring 1, which in the represented embodiment of Figure 2 is of spherical formation in the lower region which faces the opening 2, whereas the upper region adjoining the spherical region is on the other hand of cylindrical formation, as also is also evident from the example of Figure 1. In the region of the opening 3 the formation variant of -8- Figure 2 has a collar region which is provided with a number of radially projecting tooth regions. The web 4 according to the invention extends from the collar-shaped region of the bearing ring 1 over the centre of the opening 3 similarly to the embodiment of Figure 1. An intermediate gap 7 is again located between the shell parts la and lb, this serving to compensate for tolerances, similarly to the embodiment of Figure 1. List of reference characters 1 bearing ring 2 opening 3 opening 4 web la shell part lb shell part 5 projection 6 projection 7 intermediate gap -9- WE CLAIM : 1. Bearing shell of plastics material for a ball-and-socket joint for mounting a ball-and-socket joint pin which is held in a rotatable and pivotable manner in the bearing shell, with at least two shell parts (la, lb) forming an. internal bearing face shaped in the form of a hollow sphere, wherein the shell parts form, as a whole, a bearing ring (1) with a respective opening (2, 3) disposed at the opposite front sides of the bearing ring, and wherein at least one Web (4) which connects the shell parts (la, lb) is disposed transversely over one of the opening cross sections. 2. Bearing shell according to Claim 1, characterised in that the web (4) has a substantially semicircular arch shape over the opening cross section (3) of the bearing ring. 3. Bearing shell according to Claim 1 or 2, characterised in that the web (4) has a substantially rectangular cross section, wherein the larger side dimension is disposed towards the opening cross section (3) of the bearing ring (1). 4. Bearing shell according to any one of Claims 1 to 3, characterised in that the smaller side dimension of the web cross section corresponds substantially to the thickness of the bearing ring (1). 5. Bearing shell according to any one of Claims 1 to 4, characterised in that at least one projection (5, 6) is disposed at the outer edges of the bearing ring (1) as an anti-twist element. 6. Bearing shell according to any one of Claims 1 to 5, characterised in that the web (4) consists of a resilient plastics material. -10- 7. Bearing shell according to any one of Claims 1 to 6, characterised in that the bearing ring (1) and the web (4) consist of plastics materials of different extensibility. 8. Bearing shell according to Claim 7, characterised in that the plastics material of the web (4) is considerably more extensible than the plastics material of the bearing ring 1 (1). 9. Bearing shell according to any one of Claims 1 to 8, characterised in that the bearing ring (1) consists of PEEK material. 10. Bearing shell according to any one of Claims 1 to 9, characterised in that fibre reinforcements are embedded in the plastics material. 11. Bearing shell according to any one of Claims 1 to 10, characterised in that a narrow intermediate gap (7) is disposed between the shell parts (la, lb) of the bearing ring. 12. Bearing shell according to any one of Claims 1 to 11, characterised in that the web (4) between the shell parts is formed to prevent twisting of the bearing shell in a corresponding joint housing. HIRAL CHANDRAKANT JOSHI AGENT FOR ZF FRIEDRICHSHAFEN AG Dated this 2nd day of November, 2006. -11 - Abstract The invention presents a bearing shell of plastics material for a ball-and-socket joint for mounting a ball-and-socket joint pin which is held in a rotatable and pivotable manner in the bearing shell, with at least two shell parts la, lb forming an. internal bearing face shaped in the form of a hollow sphere, wherein the shell parts form, as a , wftole, a bearing ring 1 with a respective opening 2, 3 disposed at the opposite front sides of the bearing ring, and wherein at least one web 4 which connects the shell parts la, lb is disposed transversely over one of the opening cross sections. To The Controller of Patents The Patent Office Mumbai RG. 1 -12- Figure 1

Documents:

1296-MUMNP-2006-ABSTRACT(23-4-2009).pdf

1296-mumnp-2006-abstract-1.jpg

1296-mumnp-2006-abstract-1.pdf

1296-mumnp-2006-abstract.pdf

1296-mumnp-2006-cancelled pages(6-8-2009).pdf

1296-MUMNP-2006-CLAIMS(23-4-2009).pdf

1296-MUMNP-2006-CLAIMS(6-8-2009).pdf

1296-MUMNP-2006-CLAIMS(AMENDED)-(6-8-2009).pdf

1296-mumnp-2006-claims(granted)-(31-12-2009).pdf

1296-mumnp-2006-correspondance-others.pdf

1296-mumnp-2006-correspondance-received-091106.pdf

1296-MUMNP-2006-CORRESPONDENCE(23-4-2009).pdf

1296-mumnp-2006-correspondence(6-2-2007).pdf

1296-MUMNP-2006-CORRESPONDENCE(6-8-2009).pdf

1296-mumnp-2006-correspondence(ipo)-(31-12-2009).pdf

1296-mumnp-2006-description (complete).pdf

1296-MUMNP-2006-DESCRIPTION(COMPLETE)-(23-4-2009).pdf

1296-MUMNP-2006-DESCRIPTION(COMPLETE)-(6-8-2009).pdf

1296-mumnp-2006-description(granted)-(31-12-2009).pdf

1296-MUMNP-2006-DRAWING(23-4-2009).pdf

1296-mumnp-2006-drawing(granted)-(31-12-2009).pdf

1296-mumnp-2006-drawing.pdf

1296-MUMNP-2006-EXAMINATION REPORT REPLY(6-8-2009).pdf

1296-MUMNP-2006-FORM 1(23-4-2009).pdf

1296-mumnp-2006-form 1(29-1-2007).pdf

1296-mumnp-2006-form 1(3-11-2006).pdf

1296-mumnp-2006-form 2(23-4-2009).pdf

1296-mumnp-2006-form 2(granted)-(31-12-2009).pdf

1296-MUMNP-2006-FORM 2(TITLE PAGE)-(23-4-2009).pdf

1296-mumnp-2006-form 2(title page)-(granted)-(31-12-2009).pdf

1296-mumnp-2006-form 26(6-2-2007).pdf

1296-mumnp-2006-form 26(6-8-2009).pdf

1296-MUMNP-2006-FORM 3(23-4-2009).pdf

1296-mumnp-2006-form-18.pdf

1296-mumnp-2006-form-2.doc

1296-mumnp-2006-form-2.pdf

1296-mumnp-2006-form-3.pdf

1296-mumnp-2006-form-5.pdf

1296-MUMNP-2006-MARKED COPY OF AMENDED CLAIMS(6-8-2009).pdf

1296-mumnp-2006-marked copy(6-8-2009).pdf

1296-MUMNP-2006-PCT-ISA-237(23-4-2009).pdf

1296-mumnp-2006-specification(amanded)-(6-8-2009).pdf

1296-mumnp-2006-wo international publication report(6-2-2007).pdf

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