WO1994013967A1

WO1994013967A1 - A bush assembly

Info

Publication number: WO1994013967A1
Application number: PCT/AU1993/000590
Authority: WO
Inventors: Gordon Joseph Taylor
Original assignee: TAYLOR, Norma, Elsie
Priority date: 1992-12-16
Filing date: 1993-11-19
Publication date: 1994-06-23
Also published as: TW235990B

Abstract

A bush assembly for use with a torque rod, stabilizing bar or steering arm includes a housing member (71) having an inner part-spherical or arcuate surface (72), a one-part bush (74) within the housing member (71) having a bore therethrough, and an outer part-spherical or arcuate surface (75) corresponding to the inner surface (72) of the housing member (71). A shaft (76) located within the bore of the bush (74) has a waisted portion (78) which receives a correspondingly shaped reduced diameter portion (79) of the bush (74), thus ensuring positive securement between the bush (74) and the shaft (76). Other ways of fastening the two are also disclosed.

Description

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

BACKGROUND OF THE INVENTION

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. A sleeve member of this type 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 were extremely costly to repair and the usual method which was adopted was to disconnect the torque rod or beam from the chassis and then deliver 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 using the large press at the press mill. The beam or rod was then returned back to the garage for reattachment to the vehicle chassis. Also, the bonded rubber did not have a long operational lifetime because of its tendency to crack or fracture under repeated flexing, 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 embedded within the mount or fixed to an outer surface thereof and at least one axial end of the mount extended beyond the adiacent end of the outer member.

Specification 4007924 also shows an embodiment where the bushes have an inner part spherical surface complementary to the outer surface of a stud received within the bushes. Such a construction is similar to that of U.S. patent specification 3086801 referred to below and suffers from similar disadvantages.

Such mounts were complex to construct and the mount required reinforcement of its axial ends.

United States patent specification 3086801 discloses a sealed loaded joint assembly having a ball stud with a central ball head generally spherical in shape. A split resilient bush with inner contoured surfaces matching the shape of the ball head locates around the ball head. The outer face of the split bush is cylindrical and locates with an aperture in a radius rod. This aperture has an inwardly extending flange at one end and groove for a circlip at the other end. The split bush is held relative to the aperture between the flange. Dust covers protect outer edges of the split bush.

The assembly of U.S. patent specification 3086801, because of its construction, does not provide for a large freedom of pivotal movement about a longitudinal axis along the stud. This is because the part spherical surface of the bush is present on its inner face with the outer face being cylindrical. This assembly is not particularly resistant to force applied to the stud in the direction of its longitudinal axis. Such force tends to lead to easy separation of the stud and bush from the aperture in the rod.

British patent specification 637901 discloses various embodiments of self aligning joints or bearings. These embodiments either provide for limited pivotal movement about a longitudinal axis through the inner member or little resistance to forces applied to the member in the direction of the longitudinal axis.

OBJECT 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.

DISCLOSURE OF THE INVENTION According to one embodiment the invention provides a bush assembly including a housing member having an inner part spherical or arcuate surface, a one part bush within the housing member and having a bore therethrough and an outer part spherical or arcuate surface, a shaft located within the bore, complementary engagement means provided on the bore through the bush and the shaft enabling the bush to be mounted relative to the shaft.

The shaft may be substantially solid and have attachment portions at its ends. Alternatively, the shaft may have a longitudinal bore therethrough adapted to receive a fastener. If the shaft has a bore, that bore may either be cylindrical or tapered in configuration. The shaft may have a substantially cylindrical portion about which the bush is received. In which case the bore through the bush is also substantially cylindrical in shape. Alternatively, that portion of the shaft about which the bush is received may have a part spherical or arcuate surface and in which case the bore through the bush may be correspondingly part spherical or arcuate in shape.

The complementary engagement means may comprise a waisted portion on the shaft and complementary shaped reduced diameter portion in the bore of the bush. Alternatively, the shaft may have an enlarged diameter portion and the bore of the bush may have a groove of a shape corresponding to the enlarged diameter portion on the shaft. In another embodiment the complementary engagement means may comprise one or more abutments provided on the shaft and the bush may have portions thereof shaped to conform with at least part of the abutment. The abutments may be integrally formed with the bush or securable thereto. If securable to the shaft, the abutments may comprise washers. A fastener may be used to hold the or each washer in place on the shaft. The fastener may comprise a circlip and in which case the shaft has a circlip receiving groove.

The housing member may be provided with one or more radially extending lubrication ports. These ports enable lubricant to be introduced between the housing member and the bush to lubricate the contacting part spherical or arcuate surfaces. These ports also enable lubricant to escape from between the housing member and the bush during assembly. If desired a respective grease nipple may be mounted relative to these ports.

The housing may comprise a sleeve within which the shaft and bush are received and the assembly may be positioned within an aperture in a torque rod, stabilising bar or the like. Alternatively, the housing may be provided by an aperture in one end of a rod with the aperture having the part spherical or arcuate surface complementary to the outer part spherical or arcuate surface of the bush.

DISCLOSURE OF THE DRAWINGS Particular preferred embodiments of the invention will now be described by way of example with reference to the drawings in which:

Figure 1 is an exploded longitudinal sectional view of a bush assembly according to one embodiment of the invention;

Figure 2 is an exploded sectional view of a bush assembly according to another embodiment of the invention;

Figure 3 is an assembled sectional view of an alternative bush assembly according to an embodiment of the invention;

Figure 4 is an assembled sectional view of an alternative bush assembly according to an embodiment of the invention; Figure 5 is an assembled sectional view of an alternative bush assembly according to an embodiment of the invention; Figures 6a and 6b are sectional end and side views respectively of an alternative sleeve which may be used with the bush assembly of the invention;

Figure 7 is an assembled sectional view of a bush assembly according to another embodiment of the invention; and

Figure 8 is an assembled sectional view of a bush assembly according to another embodiment of the invention. DETAILED DESCRIPTION OF THE DRAWINGS

With reference to Figure 1 the bush assembly 10 has a shaft 11, a bush 12, a housing member 13 and a washer 14. The shaft 11 has attachment portions 15, 16 at its ends. Abutment 17 extends radially outwardly of the shaft 11. Abutment 17, in this embodiment, is integrally formed with the shaft but does not need to be. The abutment may, for example, comprise a collar or washer held in place by a circlip.

Immediately adjacent abutment 17, the shaft has a cylindrical portion 18. A further cylindrical portion 19 is spaced from portion 18 and terminates in a shoulder 20. A circlip retaining groove 21 is located adjacent the shoulder 20. Shaft 11 has a part spherical surface 21a extending between cylindrical portions 18 and 19. Bush 12 has an outer part spherical surface 25 and an inner part spherical surface 26. The bush 12 has cylindrical bore portions 27, 28 which engage with cylindrical portions 18, 19 of the shaft. Stepped portions 29, 30 receive the abutment 17 and washer 14 respectively.

Housing member 13 has two radially extending ports 35, 36 for lubrication purposes. Grooves 37, 38 in end faces of the member 13 are useful in locating a tool for assembling and disassembling the bush assembly. Housing member 13 has an inner part spherical surface 39 terminating in cylindrical portions 39a. Washer 14 has a stepped portion 40 which receives portion 19 and locates around shoulder 20.

Figure 2 shows another embodiment of bush assembly 50 according to the invention. Like numerals for like parts to that shown in Figure 1 are used in Figure 2. In this embodiment bush 12, housing member 13 and washer 14 are substantially identical to the like components shown in Figure 1. Shaft 51 in this embodiment is hollow and has a tapered bore 52. Abutment 53 serves the same purpose as abutment 17 shown in Figure 1. A cylindrical portion 54 is located adjacent abutment 53. Part spherical surface 55 extends from portion 54 to cylindrical portion 56. Portion 56 terminates in a shoulder 57 about which stepped portion 40 of the washer 14 locates. Circlip groove 58 receives a circlip (not shown) for holding the assembly together.

Figure 3 shows a bush assembly 60. Assembly 60 has a housing 61 which in this case is a sleeve. The housing 61 may also be provided by an end of a torque rod or arm having an aperture within which other parts of the assembly may be received. The housing 61 has a part spherical surface 62 and a bore 63. Bush 64 is received within the housing 61 and has an outer part spherical surface 65 corresponding in shape to the inner surface 62 of the housing 61. The bush has a bore for receiving shaft 66. The shaft 66* in this embodiment has a tapered bore 67. This bore may be cylindrical or if desired, the shaft may be solid in construction.

The shaft 66 has an enlarged diameter portion 68 of a shape corresponding to a circular groove in the bush and it is this groove and enlarged portion which assist in maintaining the bush in position on the shaft.

In Figure 4 the bush assembly 70 has a housing 71 which may be in the form of a sleeve as shown or could be provided by an apertured end of a rod or arm. The housing 71 has an inner part spherical surface 72 and a bore 73. Bush 74 has an outer part spherical surface 75 which matches the surface 72. Shaft 76 has a bore 77 which in this embodiment is tapered. The shaft could of course be solid in construction if desired.

In the Figure 4 embodiment shaft 76 has a waisted portion 78 which receives a correspondingly shaped reduced diameter portion 79 of the bush 74. This ensures that the bush is held relative to the shaft.

Figure 5 shows an assembled sectional view of an alternative bush assembly of the invention. In this figure assembly 80 has a housing 81. The housing may be in the form of a sleeve as shown or could be provided by an apertured end of a rod or arm. Housing 81 has an inner part spherical surface 82. Grooves 83 assist in mounting and demounting the components of the assembly 80. Housing 81 has a bore 84 for receiving bush 85 and shaft 86.

The bush 85 has an outer part spherical surface 87 which matches the shape of surface 82. Engagement abutments 88, 89 extend from and are integral with the shaft 86. Parts of the bore through the bush 85 are partly of complementary shape to the abutments 88, 89 and receive these abutments. The shaft has cylindrical portions 90, 91 between which extends a part spherical portion 92. If desired, that part of the shaft between abutments 88, 89 may be entirely cylindrical and in which case the bore through the bush would also be cylindrical rather than having a part spherical portion 93 as shown.

The shaft 86 could be hollow if desired but in this embodiment it is solid and has attachment portions 93, 94 at its ends. Figures 6a and 6b show views of an alternative housing 100 which may be used in place of the housings shown and described in other embodiments of the invention. The housing 100 is particularly suitable for use with bushes made of relatively rigid or hard material, such as nylon for example. Where the bush is made of flexible or compressible material a housing like housing 100 need not be used. Housing 100 has a bore 101 and a part spherical surface 102. At one face as best seen in Figure 6b, slots 102, 103 are provided extending into the bore 101 in a direction generally along axis 104. These access slots are chamfered as shown by the numeral 105. The slots 102, 103 extend into the bore to a location 106, 107 and have a width from location 108 to 109 corresponding to length of the bush in the direction of longitudinal axis 104. In use, to assemble the bush within the housing

100, the bush is aligned with its longitudinal axis at right angles to axis 104 and inserted into the housing through slots 102, 103. Once inside the housing the bush is rotated through 90° to enable the part spherical surfaces to engage with one another. In this way the bush does not need to be compressed to be located within the housing.

Figure 7 shows an alternative bush assembly 120. Assembly 120 has a housing 121 shown as having radial lubricating ports 122. Housing 121 has a bore 123 with a part spherical surface 124. Bush 125 is received within the bore 123 and has a part spherical surface 126 which matches surface 124.

Shaft 127 has a cylindrical bore 128. Bore 128 could be tapered if desired. Shaft 127 has an integral engagement abutment 129 and a separate engagement abutment 130 spaced therefrom. Abutment 130 is in the form of a shaped washer and extends over an end of the shaft. Abutment 130 has an aperture 131. Inner portions of the bush conform in shape to receive portions of abutments 129 and 130. The shaft 127 has cylindrical portions 134, 132 between which extends a part spherical portion 133. The bush 125 has an inner shape conforming to the shape of portion 133. A fastening member (not shown) may be located within bore 128 and a fastener at one end of that member is effective to hold abutment 130 against the shaft. Figure 8 shows an embodiment of a bush assembly similar to that of Figure 7 and like parts in Figure 8 to those of Figure 7 are identified by the numerals used in Figure 7. In Figure 8 the bush assembly 140 has a housing 100 like that illustrated in Figures 6a and 6b. The housing 100 has slots 102, 103, the chamfers 105 can be seen. The housing has a part spherical surface 141. Bush 142 is received within bore 101 and has a part spherical surface 143 which matches surface 141. , Shaft 144 has a cylindrical bore 145. Bore 145 could be tapered if required. The shaft 144 has engagement abutment 146 integral therewith and a separate engagement abutment 130 in the form of a shaped washer with an aperture 131. Parts of the bush have complementary profiles to match and receive abutments 146 and 130.

Claims

CLAIMS :

1. A bush assembly including a housing member having an inner part spherical or arcuate surface, a one part bush within the housing member and having a bore therethrough and an outer part spherical or arcuate surface, a shaft located within the bore, complementary engagement means provided on the bore through the bush and the shaft enabling the bush to be mounted relative to the shaft.

2. The bush assembly of Claim 1 wherein the complementary engagement means comprises a waisted portion on the shaft and a complementary shaped reduced diameter portion in the bore of the bush.

3. The bush assembly of Claim 1 wherein the complementary engagement means comprises an enlarged portion on the shaft and a groove in the bore of the bush of a shape corresponding to the shape of the enlarged portion.

4. The bush assembly of Claim 1 wherein the complementary engagement means comprise two abutments provided on the shaft.

5. The bush assembly of Claim 4 wherein at least one of the abutments is formed integrally with the shaft.

6. The bush assembly of Claim 4 wherein both said abutments are formed integrally with the shaft.

7. The bush assembly of Claim 5 wherein one of the abutments is provided by a shaped washer located over an end of the shaft and held in place by a fastener.

8. The bush assembly of Claim 4, 5 or 6 wherein the shaft is cylindrical in shape between the abutments and the bore through the bush is substantially cylindrical in shape.

9. The bush assembly of Claim 4, 5 or 6 wherein the shaft has a first cylindrical portion adjacent one of the abutments, a second cylindrical portion spaced from the first cylindrical portion and a part spherical or arcuate surface between the first and second cylindrical portions and the bore through the bush has a shape corresponding to the shape of the shaft between the abutment and the spaced cylindrical portion.

10. The bush assembly of Claim 7 wherein the shaped washer has a stepped profile for receiving the shaft.

11. The bush assembly of any one of Claims 1 to 10 wherein the housing member is provided by an aperture in a torque rod, stabilising bar or the like.

12. The bush assembly of any one of Claims 1 to 11 wherein the housing member is a sleeve.

13. The bush assembly of any one of Claims 1 to 12 wherein the housing member has at least one radially extending lubricating port.

14. The bush assembly of any one of Claims 1 to 13 wherein the shaft has a bore therethrough.

15. The bush assembly of Claim 14 wherein the bore is tapered.

16. The bush assembly of any one of Claims 1 to 15 wherein the bush is made of polyurethane.

17. The bush assembly of any one of Claims 1 to 15 wherein the bush is made of nylon.