GB2190152A

GB2190152A - Thrust bearings

Info

Publication number: GB2190152A
Application number: GB08702659A
Authority: GB
Inventors: Emi Ara
Original assignee: Croydon KK
Current assignee: Croydon KK
Priority date: 1986-02-07
Filing date: 1987-02-06
Publication date: 1987-11-11
Also published as: FR2612579A1; GB8702659D0; DE3643584A1; JPS62130216U

Abstract

A thrust bearing disposed between two relatively rotatable members A and B comprises first and second annular rolling plates 4 and 5 between which are needle rollers in an annular roller cage 3. The first rolling plate 4 is mounted on the member A and is provided at its outer periphery with an axially projecting outer collar and an inwardly projecting retaining lip. The second rolling plate 5 is provided at its inner periphery with an axially projecting collar 6 and an outwardly radially projecting retaining lip. The rolling plates and collars define a space accommodating the roller cage and rollers whereby the bearing may be handled as a single unit. The second rolling plate 5 is provided with one or more further axially extending projections 8, which engage the associated member B and restrain relative radial movement of the rolling plate 5 and the member B. The cage 3 is thereby prevented from contacting both rolling plates 4, 5. <IMAGE>

Description

SPECIFICATION Thrust bearings This invention relates to thrust bearings.

A conventional thrust bearing is illustrated diagrammatically in scrap axial section in Fig.

4 of the accompanying drawings. The bearing comprises a set of needle rollers 2 held in their relative positions about the axis of the bearing by a retainer or roller cage 3 having apertures 1 in which the rollers 2 are constrained to roll. The needle rollers 2 roll between first and second annular rolling plates 4 and 5. The first rolling plate 4 has, at its outer periphery, an axially projecting flange terminating in a radially inwardly projecting retaining lip which retains the roller cage 3 in loose axial alignment with the first rolling plate 4. The second rolling plate 5 constitutes a planar annular disc. Both the first and second rolling plates 4 and 5 are mounted in machined recesses in respective, relatively rotating members A and B between which the bearing is to operate.

It is a disadvantage of such known thrust bearings that each of the rolling plates has to be mounted separately; the loose second rolling plate being secured in its corresponding recess by screws or the like before the two halves of the bearing can be brought together.

To simplify the installation of such thrust bearings, an integral thrust bearing of the type illustrated in Fig. 5, has been proposed in which the second annular rolling plate 5 differs from that in Fig. 4 in that its inner edge is formed into an inner collar 6 projecting axially toward the first rolling plate 4. The rim of the collar 6 terminates in an inner retaining lip which extends radially outwardly. The roller cage 3 and first and second rolling plates 4 and 5 are thus maintained in a loose, relatively rotatable relationship with respect to each other and constitute a single unit by virtue of the inner and outer retaining lips engaging the inner and outer rims of the roller cage 3 respectively. The outer face of the second roller plate 5 bears against a face of the relatively rotatable member B.In such integral thrust bearings, particularly when mounted horizontally, the outer rim of the roller cage 3 tends to rest, when stationary, on the lowermost part of the outer collar 7. Similarly, the inner collar 6 tends to rest on the lowermost part of the inner rim of the roller cage 3. When relative rotation of the members A and B commences the roller cage 3 and the rolling plate 5 tend to rotate eccentrically and progressively to become axially aligned. However, the roller cage 3 is initially in contact with both the rolling plates which are relatively rotating and this results in wear of the contacting areas and in premature failure of the bearing.

It is an object of the present invention to provide an integral thrust bearing which is both simple to install and substantially selfaligning such that the problem referred to above is substantially eliminated.

According to the present invention there is provided a thrust bearing for transmitting thrust between two relatively rotatable members, the bearing comprising two rolling plates disposed on opposite sides of an annular roller cage retaining a plurality of rollers which, in use, are in rolling engagement with the rolling plates, the first rolling plate having at its outer periphery one or more axial projections carrying a radially inwardly extending projection and the second rolling plate having at a position spaced from its outer periphery one or more axial projections carrying a radially outwardly extending projection, the radial distance between the radially extending projections being less than the radial extent of the roller cage and the rolling plates and the projections together defining a space accommodating the roller cage and rollers, one of the rolling plates having one or more further projections extending axially away from the roller cage and arranged, in use, to engage the relatively rotatable member with which it is associated and to restrain radial movement of the second rolling plate relative thereto.

An integral thrust bearing according to the preesnt invention combines the simplicity of installation of previously known integral thrust bearing with a freedom from wear caused by contact of the roller cage with both the rolling plates.

In the preferred embodiment the further projection or projections is/are provided on the second rolling plate.

In one embodiment the rolling plates are annular and portions of the inner periphery of the second rolling plate are bent towards the roller cage to form the axial projections and further portions of the inner periphery are bent away from the roller cage to form the further projections. In a further embodiment the second rolling plate has a flange, which may be continuous or discontinuous, on its outer periphery which constitutes the further projection.

In a still further embodiment a plurality of portions of the area of the second rolling plate intermediate its inner and outer peripheries are bent out of its plane to constitute the further projections.

The present invention also embraces a bearing of the type referred to above in situ between two members which are relatively rotatable about a substantially horizontal axis with the further projection(s) engaging a surface on the associated member and restraining natural movement with respect thereto of the associated rolling plate.

The present invention may be put into practice in several ways and some embodiments will now be described by way of example with reference to Figs. 1 to 3 of the accom panying drawings, in which: Figures 1(AJ, (B) and (C) are diagrammatic sections through the lower half of three alternative constructions of bearing according to the present invention; Figure 2 is a schematic view of a rolling plate for use in the bearing of Fig. 1(A); and Figure 3 is a schematic view of a rolling plate for use in the bearing of Fig. 1(B).

Referring firstly to Fig. 1 (A), the bearing comprises a plurality of needle rollers held in angularly spaced relationship about the axis of rotation of two relatively rotatable bodies A and B in apertures in an annular roller cage 3.

The needle rollers engage first and second parallel rolling plates 4 and 5 each of which engage a corresponding face of a respective one of members A and B. The first rolling plate 4 comprises a flat annular radially extending portion on which the needle rollers bear and integral with whose outer edge is an outer flange or collar projecting generally axially towards the second rolling plate 5. The free edge of the outer collar terminates in a radially inwardly projecting retaining lip. The outer collar and associated retaining lip thus form an annular groove in which the outer edge of the roller cage 3 is constrained to run. The second rolling plate 5 comprises a flat, annular, radially extending portion, integral with whose inner edge is a plurality of axially extending lugs 6,8 which are seen most clearly in Fig. 2.The lugs 6,8 extend alternately in opposite directions, whereby the lugs 6 extend towards the first rolling plate 4 and the lugs 8 extend in the opposite direction.

The lugs 6 constitute a discontinuous inner collar or flange and terminate at their free edge with a portion which is inwardly inclined in the radial direction. The inner and outer collars together define a space which accommodates the roller cage 3 and the rollers, as in Fig. 3. The lugs 8 engage the inner surface of an axial recess C in the member B and restrain radial movement of the rolling plate 5.

When the bearing is stationary, the roller cage 3 slips to rest on the lowermost part of the outer coilar. By virtue of the support of the second rolling plate 5 by the lugs 8 on the member B, the rolling plate 5 can not move downwardly and a clearance is created between the outer face of the lugs 6 and the inner rim of the annular roller cage 3. When relative rotation of the members A and B commences, the rolling plate 4 rotates with the member A and the roller cage 3 is in contact with only one of the roller plates and the clearance between the roller cage 3 and the rolling plate 5 accommodates the initial eccentricity of rotation of the roller cage. Thus the abrasion and premature failure discribed in reiation to Fig. 3 are avoided.

In the second embodiment of the present invention, illustrated in Fig. 1(B), the lugs 8 are replaced by a peripheral collar 8' integral with the outer edge of the rolling plate 5 and projecting axially away from the rolling plate 4. This peripheral collar 8' which is best seen in Fig. 3, radially positions the second rolling plate 5 by engaging an outer shoulder d on the member B and functions in a similar manner to the lugs 8 in Fig. 8 in Fig. 1(A). Obviously, the collar 8' does not have to be continuous but could be discontinuous, e.g. in the form of castellations.

In the third embodiment of the present invention, illustrated in Fig. 1(C), the second rolling plate 5 is radially restrained with respect to the bearing face member B by means of protrusions 8" which engage in complementary recesses C in the member B. The protrusions 8" are formed by cutting and subsequently bending portions or tangs of the rolling plate intermediate its inner and outer edges in the axial direction. In this way the second rolling plate is supported relative to the first rolling plate 4 and the roller cage 3 in a similar manner to the previously described embodiments.

Claims

1. A thrust bearing for transmitting thrust between two relatively rotatable members, the bearing comprising two rolling plates disposed on opposite sides of an annular roller cage retaining a plurality of rollers which, in use, are in rolling engagement with the rolling plates, the first rolling plate having at its outer periphery one or more axial projections carrying a radially inwardly extending projection and the second rolling plate having at a position spaced from its outer periphery one or more axial projections carrying a radially outwardly extending projection, the radial distance between the radially extending projections being less than the radial extent of the roller cage and the rolling plates and the projections together defining a space accommodating the roller cage and rollers, one of the rolling plates having one or more further projections extending axially away from the roller cage and arranged, in use, to engage the relatively rotatable member with which it is associated and to restrain radial movement of the second rolling plate relative thereto.

2. A bearing as claimed in claim 1 in which the further projection or projections is/ are provided on the second rolling plate.

3. A bearing as claimed in claim 2 in which the rolling plates are annular and portions of the inner periphery of the second rolling plate are bent towards the roller cage to form the axial projections and further portions of the inner periphery are bent away from the roller cage to form the further projections.

4. A bearing as claimed in claim 2 in which the second rolling plate has a flange on its outer periphery which constitutes the further projection.

5. A bearing as claimed in claim 2 in which a plurality of portions of the area of the second rolling plate intermediate its inner and outer peripheries are bent out of its plane to constitute the further projections.

6. A bearing as claimed in any one of the preceding claims in situ between two members which are relatively rotatable about a substantially horizontal axis with the further projection(s) engaging a surface on the associated member and restraining lateral movement with respect thereto of the associated rolling plate.

7. A thrust bearing substantially as described herein with reference to Figs. 1(A) and 2, or 1(B) and 3 or 1(C) of the accompanying drawings.