WO1993008407A1

WO1993008407A1 - A bush assembly

Info

Publication number: WO1993008407A1
Application number: PCT/AU1991/000469
Authority: WO
Inventors: Gordon Joseph Taylor
Original assignee: Gordon Joseph Taylor
Priority date: 1991-01-15
Filing date: 1991-10-14
Publication date: 1993-04-29
Also published as: AU1009492A

Abstract

A bush assembly having a housing member (50), an attachment member (56) within the housing member (50) and at least one resilient bush (54, 55) between the housing member (50) and the attachment member (56). The bush (54, 55) is confined entirely within the housing member (50). One face of the bush (54, 55) is of arcuate shape and either the housing member (50) or the attachment member (56) has a face with an arcuate shape conforming to the arcuate shape of the bush (54, 55).

Description

TITLE A BUSH ASSEMBLY BACKGROUND THIS INVENTION relates to a new bush assembly for use with a torque rod, stabilizing bar or steering arm or the like.

Conventional bush assemblies for use in such applications have included as one component a sleeve member normally formed from steel and an internal lining of rubber which was bonded to the interior surface of the sleeve member. There was also normally included an attachment rod or inner shaft usually formed from metal having an enlarged portion formed as a ball or block which resiliently engaged with the rubber lining of the sleeve member. The sleeve member was normally located at each end of a torque rod by an interference fit wherein the sleeve was pressed into an associated mating end ring of the torque rod by a large press.

A conventional bush assembly for an equalizing beam was of similar construction and included a bushing member having an outer metal sleeve which was press fitted into a mating ring located at each end of the beam. Again, an internal lining of rubber was bonded to the interior surface of the outer metal sleeve. Such conventional bush assemblies in the case of repair or maintenance were extremely costly to repair and the usual method which was adopted was to disconnect the torque rod or beam from the chassis and transport the relatively heavy rod or beam to a specialised press mill equipped with a large press to disconnect the metal sleeve bushing having the bonded rubber lining from an associated end of the beam or rod. Normally, the original bushing was discarded and replaced with a new bushing which again had to be press fitted into an associated end of the beam or rod by the large press at the press mill. The beam or rod was then transported back to the garage for reattachment to the vehicle chassis. Also, once it was established that the bonded rubber did not have a long operational lifetime because of its tendency to crack or fracture under repeated flexing then the problems of replacement or maintenance of such conventional bushings became exacerbated.

Australian patent specification 21969/88 discloses an improved bush assembly having a housing member with a bore through it. One or more bushes of flexible material were located within the bore and a rod or bar passed through the bushes. Retaining members formed as part of the bar or rod held the bushes in place. The bushes had tapered outer faces and the housing member had an internal profile conforming to the exterior tapered shape of the bushes. Such assemblies, because the bushes were not bonded to the housing member could readily be disassembled for replacement of worn rubber bushes but did not provide for the requisite degree of relative movement between the components joined by the assembly such as between a steering arm and a stud fitted to the interior of the bush assembly.

U.S. patent specification 4,007,924 discloses an elastic support mount for use between an outer member having an inner surface formed generally as a surface of revolution and an inner member in the outer member and having an outer surface formed generally as a surface of revolution. In embodiments illustrated opposed axial ends of the support mount were reinforced by the provision of at least two concentric metallic reinforcing rings. The rings were either imbedded within the mount or fixed to an outer surface thereof and at least one axial end of the mount extended beyond the adjacent end of the outer member.

Such mounts were complex to construct and the mount required reinforcement of axial ends thereof. SUMMARY OF THE INVENTION

It is an object of the invention to provide an improved bush assembly which at least minimises the disadvantages referred to above.

According to one aspect the invention provides a bush assembly including a housing member, an attachment member within the housing member and at least one resilient bush between the housing member and the attachment member and confined entirely within the housing member, one face of the resilient bush being of arcuate shape and either the housing member or the attachment member have a face with an arcuate shape conforming to the arcuate shape of the bush.

The bush may be a unitary bush made of resilient material or two separate bushes of resilient material. Alternatively the bush may comprise a composite bush having one or two bushes of resilient material and a metallic ring. The resilient material may be rubber or polyurethane.

The housing member may be substantially cylindrical in shape. Preferably the member is adapted to retain the bush. The housing member may have a retaining flange. The flange may be annular in shape and be located adjacent an end of the housing member. Either the housing member or attachment member may have a groove for receiving a retainer, the retainer may comprise a circlip and the groove is spaced from the flange. Alternatively, a circlip groove may be provided on the attachment member.

It is preferred that lubricating openings extend through the housing member and the bush. The opening in the housing member may comprise a circumferential groove and one or more radial apertures through the housing member. Apertures may extend through the bush or a space may be provided between adjacent bushes.

The attachment member may be tubular. Alternatively, the attachment member is substantially solid and cylindrical. If desired the attachment member may have attachment portions at its ends . BRIEF DESCRIPTION OF DRAWINGS The invention will now be described by way of example with reference to the drawings in which:

Figure 1 is a partial exploded perspective view of part of a vehicle suspension system including stabilizing members such as torque rods and equalizing beams to which the bush assembly of the invention is fitted;

Figure 2 is an exploded perspective view of a steering arm of a front suspension to which a bush assembly according to the invention may be fitted;

Figure 3 is a longitudinal sectional view of a bush assembly according to one embodiment of the invention; Figure 4 is a longitudinal sectional view of a bush assembly according to another embodiment of the invention;

Figure 5 is a longitudinal sectional view of a bush assembly according to yet another embodiment of the invention; Figure 6 is a longitudinal sectional view of yet another embodiment of a bush assembly according to the invention;

Figure 7 is an exploded longitudinal sectional view of a further embodiment of the invention; and Figure 8 shows a perspective view of the bush assembly of Figure 7.

DETAILED DESCRIPTION Figure 1 shows a vehicle suspension including a hanger frame 1, saddle assembly 2, cap 3, attachment stud 4, washers 5 and nuts 6. An equalizing beam 7 receives cross tube 8 which has a centre bush 9.

One end 10 of the beam 7 has a bush according to the invention fitted within end ring 11. The bush has a housing member 12, two resilient bushes 13, 14 and an attachment member 15. A circlip 16, bolt 17 with abutment flange 18 washer 19 and nut 20 holds the bush assembly together and secures the arm 7 in place. Also shown in Figure 1 are a torque rod 25 attached to a frame bracket 26, bushes according to embodiments of the invention are located at 27.

Figure 2 shows part of a suspension for the front of a vehicle. Arm 30 has two bush assemblies according to the invention fitted to it. These assemblies have a housing member 40, an attachment member 41 and two bushes 42, 43. The assemblies are held together by bolt 44, circlip 45, washer 46 and nut 47. Figure 3 shows greater detail of a bush assembly. The assembly has a housing member 50 having a circumferential groove 51 with diametrically opposed lubricating channels 52. Member 50 has an annular end wall 53. Resilient bushes 54, 55 extend between attachment member 56 and member 50. In this embodiment resilient bushes 54, 55 have a curved or arcuate inner profile to match the curved or arcuate profile of an intermediate profile of member 56. The bushes 54, 55 are retained in position by washer 57 and circlip 58. Circlip 58 is received within a groove formed in member 50. Member 56 has a bore 59. Lubricating channels 52 lead into a space 60 between bushes 54, 55. If desired bushes 54, 55 may be provided as a unitary piece and in which case space 60 is substituted by a plurality of radial apertures through the unitary bush.

The embodiment shown in Figure 4 has a substantially cylindrical attachment member 65 in the form of a sleeve with circumferential flange 66 and bore 67. Bushes 68, 69 are provided between member 65 and housing member 70. In this case the bushes have outer curved or arcuate profiles which match an inner curved or arcuate profile on the housing member 70. Instead of two individual bushes a unitary resilient bush may be used. If that is the case the space 71 may be replaced by radial apertures. Member 70 has a circumferential groove 72 leading to lubricating bore 73. The bushes 68, 69 are held in place by washer 74 and circlip 75. The circlip is received within a groove formed in member 65.

The embodiment of Figure 5 is similar to that of Figure 3 except that the attachment member 80 is a solid member having apertured attachment portions 81 at its ends. Housing member 82 has an end flange 83 spaced inwardly of one end. In this embodiment the bush 84 is provided as a unitary bush of resilient material and has radial lubricating holes 85. The member 82 has a circumferential groove 86 and radial lubricating holes 87. The bush 84 is held in place by washer 88 and circlip 89. The circlip 89 is received within a groove in an inner surface of member 82. The intermediate part of attachment member is of a substantially spherical shape and has a flat cylindrical portion 90. The inner surface of bush 84 matches the contour of the intermediate part of member 80.

In the final embodiment shown in Figure 6 the attachment member 95 has apertured attachment portions 96 and the bushes 97, 98 are retained relative to an intermediate cylindrical part of member 95 by a washer 99 and circlip 100. The circlip locates in a groove on member 95. In this embodiment a metal ring 101 locates between bushes 97, 98 and housing member 102. The ring

101 has helical lubricating channel 103 formed in its outer periphery and has an outer curved profile which matches the inner profile of housing member 102. In this embodiment bushes 97, 98 together with ring 101 together form a composite bush between housing member 102 and member 95. Housing member 102 has a circumferential groove 104 and radial lubricating holes 105.

In all of the embodiments of the invention the assemblies can readily be disassembled because the unitary bush or bushes are not bonded to any of the components of the assembly. The bushes when either present as a unitary bush, two bushes or a composite bush, the assembly is self entering because of the matching arcuate or curve profiles referred to. This provides for a greater degree of movement between the parts connected by the assembly, for example between a steering arm and a stud fitted to the attachment member. The degree of movement ensures that the assembly has a longer useful life.

The bush assembly of the invention may be directly fitted to the eye of a torque rod, stabilizing bar or steering arm or the like. In which case the housing member 50 (Figure 3) 70 (Figure 4), 82 (Figure 5) or 102 (Figure 6) may in fact be provided by the eye of the rod, bar or arm to which the assembly is fitted. Alternatively, the bush assembly with a housing member like that shown in the embodiments of Figures 3 to 6 may be fitted directly into the eye of the rod, bar or arm. With reference to Figure 7, the assembly 110 consists of an attachmemt member 111 which in this case is a pin. A resilient bush consisting of two bush parts 112, 113 are present and each part has a contoured inner surface. The member 111 has an outer contoured surface confirming to interior of parts 112, 113. Two washers 114, 115 are present as is circlip 116. A rod 117 (arm or bar) having an eye 118 is adapted to receive the components just mentioned. The rod end provides directly the housing member identified by numerals 50, 70, 82 and 102 in the embodiments shown in Figures 3, 4, 5 and 6. Flange 119 is present in the eye 118. Flange 119 may be provided by a circlip fitted in the eye 118 of the rod 117.

Figure 8 shows how the bush may be assembled. Washer 114 is fitted within rod end 117, part 112 is fitted over the pin 111 and the contoured part of the pin 111 is lubricated and fitted into washer 114 within rod end 117. Part 113 is then fitted over pin 111 and into rod end 117. Washer 115 is fitted over pin 111 and into rod end 117 and the circlip 116 placed against the washer 115.

The rod end 117 is supported at A-A (Figure 8) and fitting tube 120 pressed against the assembly until the bush parts compress sufficiently to allow fitting of the circlip 116. The tube 120 can then be removed and discarded. The pin can be rotated to the desired angle and a grease nipple may be fitted to the rod end if desired.

The embodiments shown in Figures 3 and 5 may be modified by making retaining flanges 53 and 83 less pronounced and employing an additional washer retained against the inner face of the flange.

Claims

I CLAIM:

1. A bush assembly including a housing member, an attachment member within the housing member and at least one resilient bush between the housing member and the attachment member and confined entirely within the housing member, one face of the bush being of arcuate shape and either the housing member or the attachment member having a face with an arcuate shape conforming to the arcuate shape of the bush.

2. The assembly of Claim 1 wherein the busy comprises two separate bush parts and both said parts having an arcuate face which provide the arcuate shape.

3. The assembly of Claim 1 wherein said bush has at least one radially extending lubricating aperture.

4. The assembly of Claim 1 wherein said housing member is substantially cylindrical.

5. The assembly of Claim 1 including a circumferential groove extending around the housing member and at least one radially extending aperture through the housing member enabling the bush to be lubricated.

6. The assembly of Claim 1 wherein one end of the housing member has a retaining flange and the other end of the housing member has a groove for receiving a circlip, the bush being held relative to the attachment member by the housing member and between the retaining flange and a circlip in said circlip receiving groove.

7. The assembly of Claim 1 wherein one end of the housing member has a retaining flange and the attachment member adjacent the other end of the housing member has a groove for receiving a circlip, the bush being held rel cive to the attachment member by the housing member and between the retaining flange and a circlip in said circlip receiving groove.

8. The assembly of Claim 1 wherein the attachment member has a retaining flange adjacent one end of the housing and either the other end of the housing member or the attachment member adjacent the other end of the housing member having a circlip receiving groove, the bush being received between the retaining flange and a circlip in said circlip receiving groove.

9. The assembly of Claim 6 including a washer between said bush and said circlip.

10. The assembly of Claim 7 including a washer between said bush and said circlip.

11. The assembly of Claim 8 including a washer between said bush and said circlip.

12. The assembly of Claim 1 wherein said bush is a composite bush including at least one resilient part and an outer metal ring bonded thereto.

13. The assembly of Claim 10 wherein said ring has said arcuate shape which conforms to the arcuate shape of the housing member.

14. The assembly of Claim 1 wherein said bush has a convex curved said one face.

15. The assembly of Claim 1 wherein said bush has a concave curved said one face.

16. The assembly of Claim 1 wherein said housing is provided by an eye through a rod.

17. The assembly of Claim 1 wherein said housing is provided by an eye through an arm.

18. The assembly of Claim 1 wherein said housing is provided by an eye through a bar.

AMENDED CLAIMS

[received by the International Bureau on 24 March 1992 (24.03.92); original claims 1-18 replaced by amended claims 1-8

(1 page)]

1. A bush assembly including a housing member having a substantially cylindrical bore therethrough, an attachment member within the housing member and having a generally spherical portion located within the housing member, a substantially flat cylindrical portion extending around the spherical portion and in a direction transversely of the housing member, two resilient bushes entirely within the housing member and located between the housing member and the attachment member and spaced apart by a distance corresponding to the width of the flat cylindrical portion, the bushes each having a continuous inner spherical surface conforming to and abutting the spherical portion of the attachment member, the space between the bushes leaving the flat portion uncovered, at least one radial aperture through the housing member and in communication with the flat portion, one end of the housing member having an inwardly directed retaining flange and the other end having a groove for receiving a circlip with the bushes being located between the retaining flange and the groove.

2. The assembly of Claim 1 wherein said housing member is substantially cylindrical.

3. The assembly of Claim 1 including a circumferential groove extending around the housing member and extending through the groove enabling the bush to be lubricated.

4. The assembly of Claim 1 wherein said bush as each are composite bushes including at least one resilient part and an outer metal ring bonded thereto.

5. The assembly of Claim 4 wherein said ring has said arcuate shape which conforms to the bore of the housing member.

6. The assembly of Claim 1 wherein said housing is provided by an eye through a rod.

7. The assembly of Claim 1 wherein said housing is provided by an eye through an arm.

8. The assembly of Claim 1 wherein said housing is provided by an eye through a bar.