GB2026085A - Socket housing for a ball and socket joint - Google Patents

Abstract

This invention relates to ball and socket joints for the suspension systems of vehicles, and in particular to the housing 12 of such a joint. The housing being formed by cold extrusion of a metal billet so that a bearing support surface 13 in the socket is formed during the cold working of the billet, and indentations eg the screw threads 14 shown on the outside of the housing for mounting the housing in its operable position are produced either during the extrusion or by subsequent cold working of the socket. <IMAGE>

Description

SPECIFICATION Socket housing for a ball and socket joint This invention relates to ball and socket joints for, but not exclusively for, the suspension systems of vehicles.

It is known to form the socket housings of ball joints by forging and hammering the initial shape of the housing, followed by machining the housing to the exact shape required. This machining operation is wasteful of material in that a great deal of swarf is formed, and is also wasteful of time in that the swarf hampers the machining operation.

The object of the present invention is to provide a ball and socket joint in which the socket housing is formed with a minimum of waste material and substantially no machining.

British Patent Specification No. 810,330 shows a vehicle suspension ball and socket joint in which the socket housing is formed from two pressed sheet steel cups which are spot welded together. The joint is fixed to the vehicle suspension members by a threaded cup like extension drawn integrally in the base of one of the pressed steel socket members.

This construction has two disadvantages in that if the head of the ball pin is supported in an elastically deformable bearing then the bearing may be extruded into the cup like extension unless some other support is provided in the socket, and furthermore the threads on the thin sheet metal of the drawn extension may not be coarse enought to take the loads inflicted on a vehicle suspension.

Accordingly there is provided a socket housing for a ball and socket joint of a vehicle suspension system and which is formed with a socket having a bearing support surface for a bearing and an indented means in the external surface of the housing for mounting the socket member in its operational place, both the bearing support surface and the indented means being produced to their finished shape by cold working of a metal billet.

Also according to this invention there is provided a ball and socket joint having a socket housing as previously disclosed wherein the cold formed socket housing is substantially cup shaped and a pin with a bearing head projects through the mouth thereof, the bearing head being rotatable in a bearing supported on the support surface and said pin and bearing are held within the socket housing by an annular member located at the mouth of the socket.

Preferably the annular member is rotationally locked relative to the socket housing and has spanner engaging means on the exterior thereof to facilitate the attachment of the joint to a vehicle suspension member.

Also according to this invention there is provided a method of manufacture of a ball and socket joint having a pin with a bearing head thereon the head being rotatable in a bearing supported in a socket housing, said method of manufacture including the step of forming a socket housing by cold working a metal billet, the cold formed socket housing having an in-situ formed finished bearing support surface, and a means for mounting the socket housing in place is indented into the external surface of the housing.

The invention will be described by way of example and with reference to the following drawings in which: Figure 1 is a ball and socket joint according to this invention showing, on one side of the centre line CL, the joint prior to rolling over; Figure 2 shows a section through the socket housing according to this invention as is utilised in Fig. 1 after cold extrusion and with a thread rolled onto its outer surface; Figure 3 shows a section through the annular securing member of Fig. 1; and Figure 4 is a plan view of the annular securing member of Fig. 3.

With reference to Fig. 1 to 4 of the drawings, the ball and socket joint 11 has a substantially cup shaped socket housing 1 2 having an internal concave hemi-spherical bearing support surface 1 3 and a screwthread 1 4 on its outer cylindrical surface. The bearing support surface is lined by a nylon bearing 1 5 in which the bearing head 1 6 of a ball pin 1 7 is rotatably received.

The nylon bearing 115 is a snap-over type bearing supporting the spherical head 1 6 on both sides of an equatorial line and is therefore, slotted on the side of equator adjacent the mouth 1 8 of the socket housing 1 2.

The bearing 1 5 and ball pin 1 7 are secured in the housing by an annular member which comprises a washer 1 9 and an annular securing member 20.

The washer 1 9 is located against the mouth 1 8 of the socket and the pin projects through the hole in the centre of the washer, which is of such a diameter that the bearing 1 5 and head 1 6 cannot pass through it. The annular securing member 20 is concentric with the housing 1 2 and is placed in position by passing the member 20 over the housing from that end of the housing 1 2 opposite the mouth.An internal shoulder 22 on the annular member 20 abuts against a co-operating external shoulder 23 on the housing so as to limit axial movement of the securing member towards the mouth 1 8 of the socket housing, and an end portion 24 of the member 20 is rolled over so as to trap the outer peripheral margin of the washer 1 9 against the mouth 1 8 of the housing so as to secure the washer 1 9 in position.

A rubber boot 25 seals the mouth 1 8 of the socket against the ingress of dirt.

The annular securing member 20 is locked rotationally relative to the housing 1 2 by eight internal equiangularly spaced flutes 27 adjacent the shoulder 22 that engages with cooperating lugs 26 on the external surface of the housing 1 2 adjacent the mouth 1 8. The external cylindrical surface of the securing member has a hexagon 28 formed thereon to provide an engagement for a spanner to facilitate fitting the joint to a vehicle suspension member.

The socket housing 1 2 is formed by cold extrusion techniques in which a slug or billet of steel is placed into a closed die and a punch is forced rapidly into the slug to back extrude the steel around the punch. This process is known as back or impact extrusion.

The cold formed socket housing 1 2 then has a screw-thread 1 4 indented into its external cylindrical surface by rolling the thread into the surface.

The hemi-spherical bearing support surface 1 3 is formed in-situ on the socket housing during the cold forming process and no further machining is required before the bearing head 1 6 with bearing 1 5 already fitted is placed into the housing.

The annular securing member is conveniently formed by powder sintering techniques and therefore substantially no finishing by machining is necessary for both the socket housing and the annular securing member so that no swarf waste is created.

Claims (10)

1. A socket housing for a ball and socket joint of a vehicle suspension system, said housing being formed with a socket having a bearing support surface for a bearing and indentations in the external surface of the housing for mounting the joint in its operation position, both the bearing support surface and the indentations being produced to their finished shape by cold working of a metal billet.

2. A socket housing as claimed in Claim 1, wherein the indentations which provide the means for attachment of the socket housing to the vehicle suspension member are a screwthread.

3. A ball and socket joint having a socket housing as claimed in Claim 1 or Claim 2, wherein the cold formed socket housing is substantially cup shaped and a pin having a bearing head projects through the mouth thereof, the bearing head being rotatable in a bearing supported on the support surface and said pin and bearing are held within the socket housing by an annular member located at the mouth of the socket.

4. A ball and socket joint as claimed in Claim 3, wherein the annular member is rotationally locked relative to the socket housing by co-operating inter-engaging tongues and grooves present on the annular member and housing.

5. A ball and socket joint as claimed in Claim 4, when dependant upon Claim 2, wherein the annular member has spanner engaging means on the exterior thereof to facilitate the attachment of the joint to a vehicle suspension member.

6. A ball and socket joint as claimed in any one of Claims 3 to 5, wherein the annular member comprises a washer, holding the bearing head and bearing within the socket housing, and an annular securing member which secures the washer to the socket housing.

7. A ball and socket joint as claimed in Claim 6, wherein the annular securing member is placed over the socket housing from that end of the housing away from the mouth thereof and there is an axial abutment limiting movement of the securing member towards the mouth of the socket, the securing member having a portion turned over the mouth so as to secure the annular washer thereto.

8. A method of manufacture of a socket housing for a ball and socket joint having a pin with a bearing head thereon the head being rotatable in a bearing supported in a socket housing, said method of manufacture including the step of forming a socket housing by cold working a metal billet, the cold formed socket housing having an in-situ formed finished bearing support surface, and indentations for mounting the socket housing in place are formed in the external surface of the housing.

9. A ball and socket joint substantially as described herein and as shown in the accompanying drawing.

10. A method of manufacture of ball and socket joints substantially as described herein.