GB2041109A - Bearing assemblies - Google Patents

Abstract

A bearing assembly for rotatably receiving a shaft, particularly a brake camshaft for a vehicle, is able to accommodate misalignment, for example caused by flexing of the vehicle under load and in motion. The bearing comprises a part spherical housing assembled from two members 2 having part spherical surfaces 4a, and a bearing bush 6 having a part spherical surface 11 which co-operates with the part spherical surface 11 which co-operates with the part spherical surfaces 4a. An extension 6a of the bush includes a rib 12 which cooperates with a slot 5 to prevent rotation of the bush in the housing. Lubricant is supplied to the bore of the bush by way of a grease nipple 13 screwed into a tapped hole in the bush. A longitudinal groove 16 in the bore intersects the hole containing the grease nipple, and that groove is intersected by an annular groove 17 from which drillings 14 carry the lubricant to the spherical bearing space 15. Seals 9 are provided to retain the lubricant in the assembly. <IMAGE>

Description

SPECIFICATION Bearing assemblies This invention relates to bearing assemblies and more particularly to bearing assemblies for the support of brake camshafts on road vehicle axles.

A brake camshaft carried by a road vehicle axle, for example the axle of an articulated trailer, is generally supported for rotation adjacent the cam in a bearing in a brake anchor bracket. It is also supported in a further bearing spaced along the axle from the brake anchor bracket and adjacent its connection to a brake operating lever, the iatter generally being connected to an air cylinder for power operation.

The vehicle may carry heavy loads which are unequally distributed over its load surface, may be driven at high speeds and over indifferent or poor road surfaces, in consequence of which the chassis of the vehicle is subject to flexing in use. In view of this it is necessary to fit a bearing for the brake camshaft which will accomodate such flexing in use without restricting freedom of rotation of the camshaft for application and release of the brakes.

Clearly a brake which locks in the brake applied condition, which might be due to binding of the camshaft, can be equally as dangerous as a brake which fails to apply for the same reason.

This invention is concerned with an improved bearing assembly to accomodate such flexings.

The present invention consists in a bearing assembly comprising two members having opposed part spherical openings therethrough which co-operate to form a bearing housing, a bearing bush having a part spherical outer surface supported by and retained between the members at the said openings and a further outer surface extending from the housing on one side thereof incorporating means for lubrication of the interface between the bore of the bush and a shaft supported thereby in use, sealing means at the bush for retention of lubricant and at least one orifice through the wall of the bush emerging within the housing whereby lubricant supplied to the interface can pass to the interface between the part spherical outer surface of the bush and the housing.

The means for lubrication may comprise a grease nipple secured in a hole through the wall of the bush. The wall section of the bush may be thickened locally to receive the grease nipple.

A thickened portion of the wall of the bush may extend to the part spherical outer surface and may co-operate with means in or on the housing to prevent rotation of the bush in the housing whilst still permitting the bush to swivel in the housing between predetermined limits of movement.

The invention will now be described by way of example with reference to the accompanying drawings in which: rigure 1 is a view on one end of a bearing assembly, and Figure 2 is a section on line A-A of Fig.

1.

Referring to the drawings, a bearing housing 1 comprises two identical members 2 which are stamped out from sheet metal. The members have peripheral holes 3 for mounting of the assembly, for example on a bracket on an axle, and a central aperture which is subsequently formed to provide a lip 4 with a part spherical inner surface 4a. This lip is slotted at 5, for a purpose to be described.

A bearing bush 6, which may be of moulded plastics material, has a bore 7 provided with grooves 8 at each end for reception of 0 ring seals 9. The bush is generally cylindrical and has a part spherical surface 11 which is received between and retained by the opposed surfaces 4a of the members 2 such that the bush is free to swivel in the housing 1 defined by those members.

The bush has an extension 6a projecting from one side of the housing, to the left hand side as viewed in Fig. 2. The extension 6a has parallel sided walls and includes a rib 1 2 extending between the end of the bush and the part spherical portion 11. The rib 1 2 provides a thickened wall which is drilled and tapped to receive a grease nipple 1 3. The rib 1 2 extends through the slot 5 in one of the members 2 and, as seen clearly in Fig. 1, serves to locate the bush and prevent its rotation in the housing whilst permitting a limited swivelling movement of the bush to compensate for misalignments arising in operation.

The bush 6 has diametrically opposed drillings 14 through its walls which emerge into a space 1 5 defined between the part spherical surface 11 and the members 2. In consequence of this construction when a shaft, for example a brake camshaft, is supported in the bush 6 and lubricant is applied under pressure through the grease nipple 13, the lubricant will not only lubricate the journal surfaces but will also pass through the drillings 1 4 to lubricate the spherical bearing surfaces 11, 4a.

The bush 6 may be provided with one or more longitudinal grooves 1 6 to assist distribution of lubricant along the bore of the bush.

Two such diametrically opposed grooves 1 6 are shown in Fig. 2, one of which grooves intersects the hole into which the grease nipple 1 3 is screwed.

An annular groove 1 7 may be provided which intersects the longitudinal grooves and the drillings 14 to facilitate transfer of lubricant to space 1 5. An annular groove (not shown) may be provided intersecting the grease nipple hole to distribute lubricant to the bore 7 opposite the nipple hole.

The bearing assembly may be built up as a unit by, for example, spot welding the members 2 together with the bush 6 assembled and retained between them. Alternatively, the assembly may be made up on fitting to an axle and secured by bolts passing through holes 3 to clamp the members 2 together.

Claims (14)

1. A bearing assembly comprising two members having opposed part spherical openings therethrough which co-operate to form a bearing housing, a bearing bush having a part spherical outer surface supported by and retained between the members at the said openings and a further outer surface extending from the housing on one side thereof incorporating means for lubrication of the interface between the bore of the bush and a shaft supported thereby in use, sealing means at the bush for retention of lubricant and at least one orifice through the wall of the bush emerging within the housing whereby lubricant supplied to the interface can pass to the interface between the part spherical outer surface of the bush and the housing.

2. A bearing assembly as claimed in Claim 1 in which the means for lubrication of the interface comprises a grease nipple secured in a through hole in the wall of the bush.

3. A bearing assembly as claimed in Claim 1 or Claim 2 in which means on the bush and the housing co-operate to prevent rotation of the bush about its longitudinal axis in the housing.

4. A bearing assembly as claimed in Claim 3 in which the co-operating means comprise an external projection on the bush adjacent the part spherical portion thereof which engages in a slot in the housing.

5. A bearing assembly as claimed in Claim 4 in which the projection has lateral clearance in the slot to accomodate a limited axial misalignment of a shaft in the bearing laterally with respect to the slot.

6. A bearing assembly as claimed in Claim 4 or Claim 5 in which the projection comprises a longitudinally extending rib on the outer surface of the bush which extends from the housing on one side thereof.

7. A bearing assembly as claimed in Claim 6 as dependent from Claim 2 in which the grease nipple is secured in a hole passing through the rib and the wall of the bush.

8. A bearing assembly as claimed in any preceding claim in which a passage in the bore of the bush connects the means for lubrication of the interface to the orifice.

9. A bearing assembly as claimed in Claim 8 in which the passage comprises in combination one or more longitudinally extending grooves and one or more annular grooves so as to provide a continuous passage between the means for lubrication of the interface and the orifice.

10. A bearing assembly as claimed in any preceding claim in which the sealing means comprises an 0 ring seal in a groove in the bore of the bush adjacent each end thereof.

11. A bearing assembly as claimed in any preceding claim in which the housing comprises two identical members connected together so that part spherical surface forming lips thereon are oppositely directed.

12. A bearing assembly substantially as described herein with reference to and as illustrated by the accompanying drawings.

1 3. An assembly comprising a brake camshaft and a bearing assembly as claimed in any of Claims 1 to 11.

14. An assembly comprising a brake camshaft and a bearing assembly substantially as described herein with reference to and as illustrated by the accompanying drawings.