GB2196704A

GB2196704A - Bearings

Info

Publication number: GB2196704A
Application number: GB08724225A
Authority: GB
Inventors: Matthew Mccormack
Original assignee: AE PLC
Current assignee: AE PLC
Priority date: 1986-10-25
Filing date: 1987-10-15
Publication date: 1988-05-05
Anticipated expiration: 2007-10-15
Also published as: GB8724225D0; GB8625588D0; GB2196704B

Abstract

A crankshaft bearing comprises a journal bearing (11) having a thrust bearing (12) attached thereto. The journal bearing has at least two axially extending projections (16) engaging a recess (20) in the thrust bearing. The thrust bearing may be welded to the journal bearing by projection welding. Should the welds break the thrust bearing (12) is prevented from dropping into the engine sump by virtue of the fact that the depth of the recess (20) and the penetration of the end face (15) and projections (16) into the recess is greater than the maximum axial movement of the crankshaft. <IMAGE>

Description

SPECIFICATION Bearings The present invention relates to a construction of bearing of the type known as a flanged bearing and commonly used, for example, in main journal bearings for internal combustion engines and compressors.

Journal bearings having flanges for accepting the axial thrust loads imposed by a shaft are wellknown. Various constructions have been proposed in the prior art where separate journal and flange elements are joined together by various means.

In many applications of such bearings the thrust flange is located and retained in a rebate or recess machined into the housing in which the bearing is fitted. If the thrust bearing becomes detached from the journal bearing for any reason no damage is caused because the thrust bearing is retained and located by its co-operating recess.

In some engine constructions, however, there is no rebate provided in which to locate and retain a thrust bearing. Such engines often employ flanged bearings wherein the journal and thrust bearing elements are of unitary construction being produced from a single piece of material. Flanged bearings of unitary construction are difficult and costly to produce and are also not particularly amenable to installation in an engine by automated assembly methods.

Where is there no provision for location and retention of the thrust bearing elements in the engine bearing housing some engine manufacturers are concerned lest in bearings fabricated from separate thrust and journal elements the thrust bearing becomes detached.

In this event the effect of a free and unretained thrust bearing would most probably be to destroy the engine.

It is an object of the present invention to provide a combined bearing having journal and thrust bearing elements in which location and retention of the thrust bearing is maintained even in the event of the two elements becoming mutually detached.

According to the present invention a journal bearing having a thrust bearing attached thereto comprises at least one axially extending projection from at least one of the journal bearing end faces, the at least each projection engaging a recess in the rear face of the thrust bearing.

The degree of axial penetration of the projection and journal bearing end face into the recess should be greater than the maximum axial movement of the co-operating shaft in the intended application.

Preferably two or more projections are pro vided on the journal bearing end face for en gaging the recess.

In a preferred embodiment of the present invention the journal bearing and thrust bearing elements are welded together. The journal and thrust bearings may, for example, be welded together by the technique of projection welding via the journal bearing projections and thrust bearing recess. Where welding together of the journal and thrust bearings is performed the projections usually fuse and the thrust and journal bearing positions move relatively closer to each other. In this case the actual end face of the journal bearing may enter the recess in the thrust bearing. Alternatively the projections may be relatively long and part only of such projections may fuse during welding.

In order that the present invention may be more fully understood examples will now be described by way of illustration only with reference to the accompanying drawings of which: Figure 1 shows part of a sectioned engine bearing housing at the bearing crown position and its cooperating crankshaft employing a bearing according to the present invention; Figure 2 shows a perspective view of the journal bearing end face and projections and part of the co-operating thrust bearing of Figure 1 prior to welding; Figure 3 shows the relative positions of the journal and thrust bearing elements of Figure 2 after welding; Figure 4 shows a view of the rear face of the thrust bearing of Figures 1, 2 and 3; Figure 5 shows a first alternative form of journal bearing; Figure 6 shows a second alternative form of journal bearing.

Referring now to Figures 1, 2, 3 and 4 and where the same features are denoted by common reference numerals. A bearing assembly is shown generally at 10 and comprises a journal bearing 11 and a thrust bearing 12.

The journal bearing 11 comprises a steel backing 13 with a bearing alloy lining 14 thereon and has an end face 15 having several projections 16 thereon. The projections 16 have a relatively fine edge 1 7 making them suitable for subsequent welding by the projection welding technique. The thrust bearing 12 also comprises a steel backing 18 with an alloy lining 19 thereon. The thrust bearing has a recess 20 formed in the steel backing 18 which co-operates initially with the end face projections 16 of the journal bearing 11. The thrust and journal bearings are joined together by the technique of projection welding via the fine edges 17 of the projections 16 to form a weld 21. During projection welding the thrust bearing 12 moves axially due to fusing of the projections 16. Movement of the thrust bearing 12 causes the end face 15 to engage the recess 20.The assembled bearing 10 rests in a housing 22 and supports a crankshaft jour nal 23 for radial loading and a crankshaft web 24 for axial loading. Should the welds 21 break for any reason the thrust bearing 12 is prevented from dropping into the engine sump by virtue of the fact that the depth of the recess 20 and the penetration of the end face 15 and projections 16 into the recess is geater than the maximum axial movement 25 of the crankshaft.

Scalloped-out portions 30 of the thrust bearing 1 2 co-operate with the raised portions 3 1 on the circumferential extremities of the end face 15. As a result of axial movement of the thrust bearing 11 during welding the end faces 33 of the portion 34 containing the recess sink below the height of the portions 31 so effectively trapping the thrust bearing 12 and preventing rotation in the event of the welds 21 breaking.

Other means of preventing rotation may of course be used and such means may include, for example, overhanging lands on bearing caps.

Figure 5 shows an alternative form of projection and end face where the projections are castellations 40 on a thinned cylindrical annular portion 41 formed from the steel backing 13. As with the previous embodiment rotation of the thrust bearing 11 may be prevented by leaving the end castellations 42 unwelded thereby trapping the end faces 33. Welding causes the castellations 40 to fuse and results in the end face 43 engaging the recess 20.

Figure 6 shows a modification of Figure 5 where the castellations 50 are axially longer.

Welding causes only partial fusing of the castellations and the end face 5 1 does not engage the recess 20. Location and retention is effected by the remaining unfused portions of the castellations 50.

Although projection welding has been described as a suitable method of joining the journal and flange bearing elements together there are several other methods which may alternatively be employed such as, for example, electron beam, laser, other electrical resistance methods.

Bearing flanges may be applied to either one or both bearing end faces. Although half-bearings have been described the present invention is of course equally applicable to full cylindrical journal bearings having circular flanges attached thereto.

Flanged bearings according to the present invention may of course be used in applications where location and retention means are provided for the thrust bearings in the housing.

Claims

1. A journal bearing having a thrust bearing attached thereto comprises at least one axially extending projection from at least one of the journal bearing end faces, the at least one projection engaging a recess in the rear face of the thrust bearing.

2. A bearing according to Claim 1 wherein there are two projections on the journal bearing end face which engage the recess in the thrust bearing.

3. A bearing according to Claim 1 wherein there are three projections on the journal bearing end face.

4. A bearing according to Claim 1 wherein there are four projections on the journal bearing end face.

5. A bearing according to Claim 1 wherein there are five projections on the journal bearing end face.

6. A bearing according to any one preceding claim wherein the projections are formed with fine edges.

7. A bearing according to any one preceding claim from Claim 1 to Claim 5 wherein the projections are in the form of castellations on the bearing end face.

8. A bearing according to any one preceding claim wherein the journal bearing end face engages the recess in the thrust bearing.

9. A bearing according to any one preceding claim wherein the thrust bearing is prevented from rotating by having the radial end faces of the recessed portion co-operate with raised portions on the circumferential extremities of the journal bearing end face.

10. A bearing according to any one preceding claim wherein there is a thrust bearing on each journal bearing end face.

11. A bearing according to any one preceding claim wherein the journal and thrust bearings are halfbearings.

12. A bearing according to any one preceding claim from 1 to 10 wherein the journal bearing is cylindrical and the thrust bearing is substantially circular.

13. A bearing according to any one preceding claim wherein the depth of penetration of the journal bearing projection and or end face into the thrust bearing recess is greater than the axial movement of a cooperating shaft.

14. A bearing according to any one preceding claim wherein the thrust bearing is welded to the journal bearing.

15. A bearing according to Claim 14 wherein the welding is by projection welding.

16. A bearing substantially as hereinbefore described with reference to the accompanying specification and Figures 1 to 4, 5 or 6 of the drawings.