GB2361964A

GB2361964A - Retainer for roller type thrust bearing

Info

Publication number: GB2361964A
Application number: GB0110658A
Authority: GB
Inventors: Paul M Cornish; Matthew G Urmaza
Original assignee: Torrington Co
Current assignee: Timken US LLC
Priority date: 2000-05-01
Filing date: 2001-05-01
Publication date: 2001-11-07
Also published as: GB0110658D0

Abstract

A one-piece solid retainer (52) comprises a disc having two sides and a central aperture (66). The disc provides a plurality of elongated, radially directed apertures for receiving rollers (54) and has a plurality of radially directed grooves (64) extending from the central aperture to an outer peripheral edge for lubricant flow. Recesses (70,72) in the radially inner and outer peripheries of the disc, communicating with the radial grooves, may enhance the flow of lubricant. Combined with rollers and inner and outer thrust washers, the retainer provides a high flow roller-type thrust bearing.

Description

2361964 RETAINER FOR ROLLER TYPE THRUST BEARING This invention relates

generally to roller-type thrust bearings and, more particularly, to roller-type thrust bearings that require a high flow of lubricant.

Thrust bearings with rollers are well known. Typically, the rollers are maintained in radial orientation by a cage that is made of two pieces of metal that are secured together with the rollers therebetween and protruding through elongated roller pockets in the cage to contact thrust washers. To provide an increased flow of lubricant to the rollers and piloting surfaces, the cages have included axially directed lubrication holes or flats along their outer periphery, as described below.

Under extreme conditions, for example in automobile torque converters, the metal cages of such bearings have shown a high rate of wear at their radially inward edges, causing the two pieces of the metal cage to separate, allowing the rollers to escape, thereby resulting in catastrophic failure of the bearings. Such failures have resulted even when the cages have included features for increased flow of lubricant.

one-piece solid cages are known, but they have been unsuitable for such conditions due to their restricted flow of lubricant.

2 According to one aspect of the invention, there is provided a one-piece solid retainer for a roller-type thrust bearing, the retainer comprising a disc having two sides and a central aperture; the disc providing a plurality of elongated, radially directed apertures for receiving rollers; and the disc having a plurality of radially directed grooves extending f rom the central aperture to an outer peripheral edge for lubricant flow.

According to a second aspect of the invention, there is provided a roller-type thrust bearing comprising an inner thrust washer; an outer thrust washer; and rollers in a one piece solid retainer and in rolling contact with the inner and outer thrust washers; the retainer comprising a disc having two sides, a central aperture, and a plurality of elongated, radially directed apertures for receiving the rollers; the disc having a plurality of radially directed grooves extending from the central aperture to an outer peripheral edge for lubricant flow.

For a better understanding of the invention and to show the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:- 3 Fig. 1 is a cross sectional view of a roller-type thrust bearing according to the prior art;

Fig. 2 is a cross sectional view of another roller-type thrust bearing according to the prior art;

Fig. 3 is a cross sectional view of a roller-type thrust bearing according to the present invention; Fig. 4 is a pictorial view of the rollers and retainer of the thrust bearing of Fig. 3; Fig. 5 is a cross sectional view of the roller-type thrust bearing of Fig. 3, showing a possible lubricant flow; is Fig. 6 is an enlarged pictorial representation of an optional configuration of the roller pocket of the retainer of Fig. 3; Fig. 7 is a pictorial view of the roller-type thrust bearing of Fig. 3, showing the side with the outer thrust washer; and Fig. 8 is a pictorial view of the roller-type thrust bearing of Fig. 3, showing the side with the inner thrust washer.

4 Referring to the drawings, Figure 1 illustrates a prior art roller-type thrust bearing 10 with a two-piece metal cage 12 holding rollers 14 in radial orientation, as described above. The rollers 14 bear against inner thrust washer 16 and outer thrust washer 18, that are held together as an assembly by cap 20. To increase the flow of lubricant, inner thrust washer 16 may provide holes at centre lines 22, and cage 12 may have segments of cage outer periphery 24 removed.

Figure 2 illustrates a prior art roller-type thrust bearing 30 with a two-piece metal cage 32 holding rollers 34 in radial orientation. The rollers 34 bear against inner thrust washer 36 and outer thrust washer 38. To increase the flow of lubricant, inner thrust washer 36 may provide apertures in a portion 40 between the rollers 34 and the inner periphery, and outer thrust washer 38 may provide apertures in a portion 42 between the rollers 34 and the outer periphery.

As described above, such prior art thrust bearings have been known to fail under extreme conditions, such as, for example, in an automobile torque converter. In spite of the provisions for increased flow of lubricant, the two-piece metal cages 12 and 32 have shown a high rate of wear at their radially inward peripheries 44 and 46, respectively, allowing the two pieces of the cages to separate and permitting the rollers to escape from the cages, resulting in catastrophic failure of the bearings.

Figure 3 illustrates an embodiment 50 of the present roller-type thrust bearing, having a one-piece solid retainer 52 holding rollers 54 in radial orientation. The rollers 54 protrude from roller pockets in the retainer 52 and bear against inner thrust washer 56 and outer thrust washer 58. To hold thrust bearing 50 together as an assembly, the thrust washers 56 and 58 may include lips 60 and 62 spun or otherwise formed over the retainer 52, to engage retainer rounded edges 63 of retainer 52, as illustrated. The retainer 52 has the configuration of a disc having two sides, a central aperture, and a plurality of elongated, radially directed apertures for receiving the rollers 54.

To increase the flow of lubricant, the retainer 52 has radially directed grooves 64 extending from a central aperture 66 to an outer peripheral.edge 68, as illustrated in Figure 4.

The radial grooves 64 may be four in number, and may have a generally round configuration in cross-section, as illustrated, or may be of other convenient number and shape.

The radial grooves 64 may be located between the roller pockets, as illustrated, so as to maintain maximum strength of the retainer 52, or may be aligned with the roller pockets to direct lubricant directly to the rollers.

To further enhance the flow of lubricant, optional recesses 70 and 72 may be provided on the central aperture 66 and/or outer peripheral edge 68, respectively, communicating 6 with the radial grooves 64 to direct lubricant to and from the radial grooves. The recesses may be round, scallop shaped as shown, or of other configuration. These optional recesses 70 and 72 are clarified further below, with reference to Figures 5, 7 and 8.

Roller pockets 74 may be provided with retention tabs 7G on both sides of retainer 52 or on only one side, as illustrated in Figure G, for retaining the rollers in the axial direction. Retention tabs on both sides are convenient when the retainer is made of a resilient polymer, allowing the rollers to be snapped into the pockets before or after mating to a thrust washer. Retention tabs on only one side facilitate manufacturing the retainer of powdered metal or rigid polymer. With one side retention, the rollers are assembled on the retainer before mating to an adjacent thrust washer.

Figure 7 shows the assembled roller-type thrust bearing 50 from the side of outer thrust washer 58. As illustrated, optional lube slots 78 may be provided in the radially directed surface of the outer thrust washer 58, radially outward of the rollers 54, to facilitate the flow of lubricant. Note, also, that the outer thrust washer 58 does not extend radially inwardly as far as the inner periphery 6G of the retainer 52, but leaves a gap allowing lubricant to 7 flow to the radial grooves 64 and the recesses 70 of the retainer 52.

Figure 8 shows the assembled roller type thrust bearing 50 from the side of inner thrust washer 5G, and illustrates that optional lube slots 80 may be provided in the radially directed surface of the inner thrust washer 56, radially inward of the rollers 54, to facilitate the flow of lubricant.

Note that the inner thrust washer 56 does not extend radially outward to the outer periphery of the retainer 52 but provides a gap allowing lubricant to flow to radial channels 64 and recesses 72. Figure 5 includes arrows indicating a possible flow of lubricant with the illustrated embodiment of the present invention.

From the above description, it will be apparent that the present thrust bearing retainer provides a higher tolerance to radial retainer wear than the two-piece metal retainers of the prior art. This is due to the retainer's one-piece configuration and, also, due to its solid volume. Even if a high amount of material is removed from the retainer bore, the rollers will stay in the pockets of the retainer, thereby avoiding catastrophic failure. In addition, the present thrust bearing has high lubricant flow due to the grooves and optional lube scallops.

8

Claims

1. A one-piece solid retainer for a roller-type thrust bearing, the retainer comprising a disc having two sides and a central aperture; the disc providing a plurality of elongated, radially directed apertures for receiving rollers; and the disc having a plurality of radially directed grooves extending f rom the central aperture to an outer peripheral edge for lubricant flow.

2. A retainer according to claim 1, wherein the grooves are located between the apertures for receiving the rollers.

3. A retainer according to claim 1 or 2, wherein the is retainer provides recesses at the central aperture in commun ication with the radially directed grooves.

4. A retainer according to claim 1, 2 or 3, wherein the retainer provides recesses at the outer peripheral edge in communication with the radially directed grooves.

5. A retainer according to any one of the preceding claims, wherein one side of the retainer has retention tabs for retaining the rollers in one axial direction.

9 G. A retainer according to any one of claims 1 to 4, wherein both sides of the retainer have retention tabs for retaining the rollers in two axial directions.

7. A retainer according to any one of the preceding claims, wherein the retainer is formed of powdered metal.

8. A retainer according to any one of claims 1 to G, wherein the retainer is formed of polymer.

9. A roller-type thrust bearing comprising an inner thrust washer; an outer thrust washer; and rollers in a one piece solid retainer and in rolling contact with the inner and outer thrust washers; the retainer comprising a disc is having two sides, a central aperture, and a plurality of elongated, radially directed apertures for receiving the rollers; the disc having a plurality of radially directed grooves extending from the central aperture to an outer peripheral edge for lubricant flow.

10. A bearing according to claim 9, wherein the retainer has recesses along its central aperture or an outer peripheral edge, in communication with the radially directed grooves, for enhancing lubricant flow.

11. A one-piece solid retainer for a roller-type thrust bearing, substantially as hereinbefore described, with reference to any one of Figures 4 to 8 of the accompanying drawings. 5

12. A roller-type thrust bearing, substantially as hereinbefore described, with reference to any one of Figures 4 to 8 of the accompanying drawings.