GB2080401A

GB2080401A - Ball joint and liner therefor

Info

Publication number: GB2080401A
Application number: GB8023564A
Authority: GB
Original assignee: Ford Motor Co Ltd; Ford Motor Co
Current assignee: Ford Motor Co Ltd; Ford Motor Co
Priority date: 1980-07-18
Filing date: 1980-07-18
Publication date: 1982-02-03
Also published as: EP0049031A1; EP0049031B1; JPS5779320A; DE3162516D1; JPH0260887B2

Abstract

A liner for a ball joint in, for example, a gear selector lever, comprises an annulus (10) of plastics material having a spherical inner bearing surface (12) for engaging a ball element and an outer surface (11) for mounting in a recess in housing. One, and prefarably each, end of the annulus is axially slotted (15) to form tongues (16a,b) which can be deflected radially to dilate the end of the annulus, allowing the ball element to be inserted. Some tongues (16a) have a spherical inner surface (17a) forming part of the bearing surface (12), others carry radial projections (18) on their outer surfaces for engaging a radial cavity in the housing recess to retain the ball element therein. The internal surface of these tongues (16b) is spaced from the spherical bearing surface to allow the assembled ball element and liner (10) to be pushed into the recess.

Description

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GB 2 080 401 A 1

SPECIFICATION

Ball joints and liners therefor

This invention relates to liners for ball joints, and ball joints including such liners.

5 A conventional ball joint, such as used to mount a gear selector lever on a gearbox, comprises a housing having a recess therein, which is usually cylindrical, a ball element pivotably received in the recess, and a bearing liner between the ball 10 element and the recess.

One known kind of liner as, for example disclosed in British Patent Specification No. 1187187, comprises an annulus of resiliently deformable plastics material having an inner 15 spherical bearing surface. In order to allow the liner to be pushed on to the ball element, at least one end portion of the annulus has a plurality of axially extending circumferentially spaced tongues. These tongues spread radially outwardly 20 to dilate the end of the annulus as the ball element is inserted into the annulus.

In order to keep the ball element and liner in the housing, a retainer, such as a spring circlip or a nut is secured to the housing in contact with the liner. 25 In the case of a gear selector lever, if a nut is used as a retainer, it is normally positioned above the ball element, where it limits the range of movement of the lever. If a circlip is used, it is usually necessary to insert shims into the housing 30 to compensate for variations in size of the ball element and the recess due to manufacturing tolerances. Assembly of the joint is therefore relatively complicated.

According to. the present invention, there is 35 provided a liner for a ball joint comprising an annulus of resiliently deformable plastics material having an inner spherical bearing surface, at least one end portion of the annulus having a plurality of axially extending circumferentially spaced 40 tongues which can be deflected radially to dilate the end of the annulus characterised in that at least some of the tongues have inner surfaces which lie in the spherical bearing surface, and at least one of the tongues has a radially outwardly 45 extending projection for retaining the liner in a bearing mounting, and an inner surface which is spaced radially outwardly from the spherical bearing surface.

In use, the liner is mounted on the ball element 50 of a ball joint with its spherical surface in sliding contact with a spherical surface of the ball element, the tongues undergoing radial deflection to dilate the end of the annulus as the ball element is inserted therein. The assembled ball element 55 and annulus can then be mounted in a housing provided with a recess for receiving the ball element and liner, the liner being retained in the recess by engagement of the or each projection with a radial cavity, for example a circumferential J30 groove, in the recess. Since the or each tongue of the annulus carrying the radial projections has an inner surface spaced radially from the spherical bearing surface of the annulus, and therefore of the ball element, the tongues can be deflected

65 radially inwardly thereby allowing the radial projections to be inserted into the recess in the housing.

In order to facilitate insertion of the annulus into the recess, the or each projection preferably 70 has a radially outer surface which is inclined at an acute angle to the external surface of the liner in a direction away from the axis of the annulus and towards the central radial plane thereof. As a result, the engagement of the projection with the 75 mouth of the recess exerts a radially inward force on the tongues. In addition, the projection preferably has another part of its surface inclined in the opposite direction so that the projections are wedge-shaped in axial cross section. This 80 ensures positive engagement of the projections in the cavity of the recess even when the relative radial and axial positions of the inner and cavity vary within manufacturing tolerances.

Preferably the other end portion of the annulus 85 also has a plurality of axially extending circumferentially spaced tongues the inner surfaces of which lie in the spherical bearing surface of the annulus. This construction permits the ball element to be introduced into the annulus 90 from either end. With such a construction, the tongues are preferably so disposed relative to ~ each other that dilation of one end of the annutes produces a contraction in the other end of the annulus. For example, the tongues may be formed 95 by slots in the annulus extending axially from the ends of the annulus, the slots at each end preferably being circumferentially interleaved to avoid weakening the annulus at its central radial plane. With such a construction, insertion of the 100 one end of the annulus into the recess is facilitated by dilating the other end of the annulus by partially inserting the ball element. The liner can also preferably expand radially, thus accommodating variations in size of the ball element within 105 manufacturing tolerances.

In order that the invention may be better understood, a preferred embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings, in 110 which:—

Figure 1 is a cross-section through a ball joint incorporating a liner in accordance with the invention;

Figure 2 is an end view on an enlarged scale of 115 a liner incorporated in the ball joint of Figure 1;

Figure 3 is an axial cross-section of the liner of Figure 2;

Figure 4 is a cross-section on an enlarged scale through part of the ball joint of Figure 1 during a 120 first stage of assembly; and

Figure 5 is a similar cross-section to Figure 4 showing the ball joint during a later stage of assembly.

Referring to the drawings, a gear selector lever 125 assembly for a gearbox comprises a housing 1

having a cylindrical recess 2 the infernal surface of which includes a radial cavity in the form of a circumferential groove 3.

A ball element 5 of sintered metal press fitted

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GB 2 080 401 A 2

on to a selector lever 6 is received in the recess 2. The ball element 5 has a spherical surface 7 of smaller diameter than the recess 5, and is retained in the recess by a liner 10, illustrated in detail in 5 Figures 2 and 3.

The liner 10 comprises a one-piece moulding of resiliently deformable plastics material, such as a self-lubricating acetal copolymer of the kind conventionally used as a bearing liner material. 10 The liner 10 is an annulus having a generally cylindrical external surface 11 which is a sliding fit with the recess 2. The internal surface 12 of the liner defines a spherical bearing surface of complementary diameter to that of the spherical 15 surface 7 of the ball element 5 so that the spherical surface 7 of the ball element 5 can make a sliding contact therewith.

Each end of the liner 10 is provided with eight axial slots 15. The slots 15 at each end extend 20 beyond the central radial plane of the liner 10 and are interleaved circumferentially with the slots at the opposite end so that the annulus has a sinuous shape which is both flexible and strong.

Adjacent pairs of slots divide the end portions 25 of the annulus into eight circumferentially spaced tongues 16,16a, 16b. The tongues at either end of the liner 10 can be deflected radially outwardly to dilate the end of the liner 10, a dilation at one end being accompanied by a contraction at the 30 other end of the annulus. This allows the ball element 5 to be inserted into either end of the annulus as illustrated in Figure 4.

All the tongues 16 at one end of the annulus have an inner surface 17 which lies in the 35 spherical bearing surface 12 of the liner 10. At the other end of the annulus however, only four of the tongues 16a have inner surfaces 17a lying in the bearing surface of the liner. The other four tongues, 16b have inner surfaces 17b which are 40 spaced radially from the spherical bearing surface 12 of the annulus 10, and which lie in a cylindrical surface parallel to the external surface 11 of the annulus 10 and tangential to the bearing surface 12 at the central radial plane of the liner 10. These 45 four tongues 16b are also provided with radially outwardly extending projections 18. Each projection is generally wedge-shaped in axial cross-section having a leading radially outer conical surface 18a which is inclined outwardly at 50 an angle A to the radial plane away from the central axis of the liner and towards the central plane thereof, and a trailing outer conical surface 18b which is inclined in the opposite direction at a smaller angle, B, to the radial plane. The bases of 55 these projections are axially wider than the groove 3 so that the extremities qf the projections engage in the circumferential groove 3 and retaining the liner 10 and the ball element 5 in the recess 2.

in order to assemble the joint, the ball element 60 5 is partially inserted into the end of the annulus opposite the projections 18, thus dilating the end into which it is inserted and contracting the opposite end. The contracted end of the annulus can then easily be introduced into the mouth of 65 the recess 3, as illustrated in Figure 4. The wedge shapes of the projections 18 facilitate this movement.

The ball element 5 is then pushed firmly into the liner 10 so that its spherical surface 7 lies in 70 contact with the bearing surface 12 of the liner. This movement causes the dilated end of the liner 10 to return to its normal size, allowing the liner to slide into the recess 3. Since the four tongues 16b carrying the projections 18 have inner surfaces 75 spaced from the spherical bearing surface 12 of the liner 10, the engagement of the projections 18 with the cylindrical internal surface of the recess 2 deflects the tongues 16b radially inwardly, so that the projections 18 are accommodated within the 80 recess 2, as illustrated in Figure 5. Since the slots 15 allow radial expansion of the liner 10, variations in size of the ball element 5 due to manufacturing tolerances can be accommodated.

Further movement of the liner 10 and ball 5 85 into the recess brings the projections into registry with the groove 3, whereupon the tongues 16b expand radially outwardly to retain the liner in position. Since the projections 18 are wedge shaped, in axial cross-section, with their faces 90 inclined at acute angles in opposite directions to the central radial plane, the projections will engage in the groove 3 regardless of small variations in the relative positions of the groove 3 and liner 10 due to manufacturing tolerances. 95 No further fixing of the selector lever 6 to the housing 1 is required, so that the movement of the lever 6 relative to the housing 1 is unencumbered by retainers such as nuts. Moreover, the use of a flexible liner 10 with wedge-shaped retaining 100 projections 18 accommodates variations in size of the recess 2 in the housing and of the ball element 5 within manufacturing tolerances, thereby avoiding the need for shims or other spacers. Indeed variations within relatively large tolerances 105 can be accommodated, which allows the components of the assembly to be manufactured by cheaper methods. For example, the ball element 5 may be of sintered metal.

Claims

110 1 ■ A liner for a ball joint comprising an annulus of resiliently deformable plastics material having an inner spherical bearing surface, at least one end portion of the annulus having a plurality of axially extending circumferentially spaced tongues which 115 can be deflected radially to dilate the end of the annulus characterised in that at least some of the tongues have inner surfaces which lie in the spherical bearing surface, and at least one of the tongues has a radially outwardly extending 120 projection for retaining the liner in a bearing mounting, and an inner surface which is spaced radially outwardly from the spherical bearing surface.

2. A liner according to Claim 1 wherein the 125 projection has part of its radially outer surface inclined at an acute angle to the external surface of the liner in a direction away from the axis of the annulus and towards the central plane thereof.

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GB 2 080 401 A 3

3. A liner according to Claim 2 wherein the projection has another part of its radially outer surface inclined in the opposite direction.

4. A liner according to any one of Claims 1 to 3 5 wherein the other end portion of the annulus has a plurality of axially extending circumferentially spaced tongues the inner surfaces of which lie in the spherical bearing surface.

5. A liner according to Claim 4 wherein the 10 tongues on each end portion are so disposed relative to each other that dilation of one end of the annulus produces a contraction in the other end of the annulus.

6. A liner for a bail joint substantially as

15 hereinbefore described, and as illustrated in the drawings.

7. A ball joint comprising a ball element having a spherical external surface, a liner according to any one of Claims 1 to 5 mounted thereon with

20 the spherical bearing surface of the annulus in sliding contact with the said surface of the ball element, and a housing having an internal surface defining a recess for receiving the ball and liner characterised in that the liner is retained in the

25 recess by the engagement of the or each projection with a radial cavity in the recess.

Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1982. Published by the Patent Office, 25 Southampton Buildings, London, WC2A 1AY, from which copies may be obtained.