GB2100337A

GB2100337A - A ball-and-socket joint

Info

Publication number: GB2100337A
Application number: GB8138692A
Authority: GB
Original assignee: ZF Lemfoerder GmbH
Current assignee: ZF Lemfoerder GmbH
Priority date: 1981-06-13
Filing date: 1981-12-23
Publication date: 1982-12-22
Also published as: DE3123590A1; FR2507712A1; FR2507712B1; GB2100337B; JPH0364728B2; IT1140432B; IT8125928A0; JPS585515A; DE3123590C2

Abstract

The ball-and-socket joint has a casing 4 in which a ball head 2 connected to a joint pin 1 is received in a bearing socket 3 disposed in the casing 4 which is closed adjacent the ball head by a cover 8. A resilient means 7 which compensates play in the joint is provided between the cover 8 and a supporting socket 5 which cooperates with the ball head 2. Improved compensation for tolerance and play is achieved by constructing the resilient means 7 as a divided annular spring. The supporting socket 5 has a circumferential surface 6 which faces outwardly and is inclined at an angle alpha to the longitudinal axis A-A of the casing 4 and at an angle beta to the perpendicular A-B to the axis A-A. The angle of inclination beta of the surface 6 can be so selected that the usual axial forces cannot change the diameter of the annular spring 7 which, however, reliably transmits an appreciable force to the supporting socket 5. <IMAGE>

Description

SPECIFICATION A ball-and-socket joint This invention relates to a ball-and-socket joint of the kind having a casing, in which a ball head connected to a joint pin is received in a bearing socket inside the casing which is closed at its end adjacent the ball head by a cover, a resilient means which compensates play in the joint being provided between the cover and a supporting socket which co-operates with the ball head. Such a joint is particularly intended for use in the steering and control linkages of motor vehicles.

A known ball-and-socket joint of this kind (German Utility Model 7714920) uses as a resilient means a helical spring combined with an additional resilient means of rubber-like plastics which is located between the supporting socket and the casing cover. Since a helical spring incorporated at this place an absorb only as much load as it provides itself, it is clear that with the usual construction dimensions a helical spring cannot absorb any heavy load. It is true that an intermediate layer of plastics can damp shocks and reduce noises while at the same time initially compensating for tolerance and play, but after a prolonged period of loading the effect of plastics parts declines.

It is therefore an object of the invention so to construct a ball-and-socket joint of the foregoing kind that even rough manufacturing tolerances can be compensated for even after a prolonged period, with wear occurring during use. The invention also enables considerabie axial forces to be absorbed-without play (clearance). The construction of the invention is simple, cheap and suitable for mass production. The constructional dimensions are comparatively small and do not exceed those of commercially available ball-andsocket joints.

Accordingly, the present invention consists in a ball-and-socket joint having a casing, in which a ball head connected to a joint pin is received in a bearing socket inside the casing which is closed at its end adjacent the ball head by a cover, a resilient means which compensates play in the joint being provided between the cover and a supporting socket which co-operates with the ball head, wherein the supporting socket has a circumferential surface which faces the casing cover and which is inclined at an angle to the longitudinal axis of the casing and at an angle to a perpendicular to said longitudinal axis, the angles of inclination of said surface, measured against the perpendicular to the longitudinal axis and the longitudinal axis itself, being respectively greater than an angle causing frictional locking of the resilient means which is constituted by a divided annular spring.

The advantage of such an arrangement is that by suitably chosing the angle of inclination it can be ensured that the annular spring loads the supporting socket with a considerable force, while a substantially greater force is needed so to deform the annular spring that a play is produced.

It is true that German Patent Specification 715826 discloses in principle the use of a radially resilient securing means in a releasable ball-andsocket joint. The securing means consists of a circlip which is located in an annular groove in the casing opening and which widens up into the annular groove when the ball head is pressed into the casing and after the passage of the ball head springs back and prevents the ball head from sliding out. Since the annular groove inevitably starts from an aperture corresponding to the diameter of the ball head, the circlip must inevitably engage in the vicinity of the ball equator after springing back.This means that although the circlip can exert a retaining function, it is unsuitable for acting with an appropriate force on the ball head in the sense of the invention for compensating tolerance and wear, or for opposing a corresponding resistance to an axial force.

Circlips and similar securing means were therefore unable to give any indication of the solution of the problem to which the invention relates.

Advantageously, the angle of inclination (a) of said surface, measured against the longitudinal axis, is greater than angle (p) measured against the perpendicular to the longitudinal axis.

Preferably, the angle of inclination (,B), measured against the perpendicular to the longitudinal axis is between 100 and 400, more particularly between 200 and 300. Conveniently, said inclined surface faces inwardly, and the diameter of the annular spring is reduced during assembly of the joint. Alternatively, said inclined surface faces outwardly, and the diameter of the annular spring is increased during assembly of the joint.

In order that the invention may be more readily understood, reference is made to the accompanying drawings which illustrate diagrammatically and by way of example embodiments thereof, and in which: Fig. 1 shows a ball-and-socket joint having an outwardly facing inclined surface on the supporting shell, and Fig. 2 shows a ball-and-socket joint having an inwardly facing inclined surface on the supporting shell.

In Fig. 1 a ball head 2 is formed integrally with a joint pin 1. The portion of the ball head adjacent the pin 1 is received in a bearing socket 3 inside a casing 4. The portion of the ball head 2 remote from the pin 1 contacts a supporting socket 5 which has an outwardly facing inclined peripheral surface 6. Bearing against the surface 6 is a divided annular spring 7 which is axially retained by a cover 8 located in the casing 4. The cover 8 is retained in position by a flanged edge 9 of the casing 4. The angle of inclination of the surface 6, measured against the axis A-A of the ball-andsocket joint, has the reference a.The angle of inclination measured against a perpendicular A-B to the axis A-A has the reference p. Each of the angles a and B is greater than an angle causing self-locking (jamming). The angle a is larger than the angle P.

The assembly of the ball-and-socket joint is such that the ball head 2 is inserted, then the supporting socket 5 together with the annular spring 7 is positioned on the ball head and the cover 8 is pressed in by means of a tool. When the cover 8 has reached its correct position, the edge 9 is flanged. When the cover 8 is pressed in, the annular spring 7 is axially loaded. The inclination of the surface 6 produces a radial component which expands the annular spring 7. The force required to expand the annular spring 7 is comparatively great on condition that a > p, and is in any case greater than the force which the annular spring 7 exerts on the supporting socket 5 in the assembled condition.

By a suitable choice of the angles, therefore, on the one hand a readily mobile ball-and-socket joint can be constructed, and on the other hand freedom from play is achieved, even under heavy axial forces. Conveniently the angle is between 100 and 400. Particularly advantageous results are given by values between 200 and 300.

In the embodiment illustrated in Fig. 2, in which the arrangement is otherwise similar to Fig.

1, a supporting socket 5' with an inwardly facing inclined surface 6' and a divided annular spring 7' acting thereon is incorporated. During assembly the annular spring 7' slides over the surface 6', at the same time reducing its own diameter. Of course, the slotting of the annular spring 7' must be of such dimensions that the opposite ends do not abut against one another. When assembly has been completed, the annular spring 7' again tends to resume its original shape, i.e. to expand outwardly in the radial direction. The axial component occurring as a result produces a playfree pressing of the supporting socket 5' against the ball head 2. In this case also the force to be applied to deform the annular spring 7' is substantially greater than that provided by the annular spring 7'.

Claims

1. A ball-and-socket joint having a casing, in which a ball head connected to a joint pin is received in a bearing socket inside the casing which is closed at its end adjacent the ball head by a cover, a resilient means which compensates play in the joint being provided between the cover and a supporting socket which co-operates with the ball head, wherein the supporting socket has a circumferential surface which faces the casing cover and which is inclined at an angle to the longitudinal axis of the casing and at an angle to a perpendicular to said longitudinal axis, the angles of inclination of said surface, measured against the perpendicular to the longitudinal axis and the longitudinal axis itself, being respectively greater than an angle causing frictional locking of the resilient means which is constituted by a divided annular spring.

2. A ball-and-socket joint as claimed in claim 1, wherein the angle of inclination (cur) of said surface, measured against the longitudinal axis, is greater than angle (p), measured against the perpendicular to the longitudinal axis.

3. A ball-and-socket joint as claimed in claim 2, wherein the angle of inclination (p), measured against the perpendicular to the longitudinal axis is between 100 and 40 , more particularly between 200 and 30".

4. A ball-and-socket joint as claimed in any of the preceding claims, wherein said inclined surface faces inwardly, and the diameter of the annular spring is reduced during assembly of the joint.

5. A ball-and-socket joint as claimed in any of claims 1 to 3, wherein said inclined surface faces outwardly, and the diameter of the annular spring is increased during assembly of the joint

6. A ball-and-socket joint, substantially as herein described with reference to and as shown in the accompanying drawings.