GB2220234A

GB2220234A - Cage with internal locking rib

Info

Publication number: GB2220234A
Application number: GB8912418A
Authority: GB
Inventors: Mitchell L Bussell
Original assignee: Torrington Co
Current assignee: Timken US LLC
Priority date: 1988-06-06
Filing date: 1989-05-31
Publication date: 1990-01-04
Also published as: FR2632368A1; KR900000609A; DE3917759A1; GB8912418D0; JPH0231021A; BR8902595A

Description

CAGE WITH INTERNAL LOCKING RIB 2220234 This invention relates to

antifriction bearings which utilize a cage-and- roller assembly. More particularly, it relates to means for limiting axial movement of the cage relative to an inner ring or race of a radial bearing. This invention is well suited for use where a bearing undergoes extensive handling during the assembly and shipping stages.

Prior art patents disclose various bearing assemblies and subassemblies which are designed to help hold the assembly together in one piece, especially during the shipping and handling stages and during the installation of the bearing. Some bearings use fasteners to hold portions of the bearing together. An example of this type of prior art is disclosed in U.S. Patent No. 2,969,266 for a "Needle Or Roller Bearing" issued in the name of Georg Shaeffler on January 24,

1961. In FIG. 3, Shaeffler discloses an inner race on which is positioned a cage having an extended axial end. Pins are inserted into this extended end, passing through the cage end into a groove in the outer surface of the inner race.

Other prior art patents disclose bearings which utilize 20 interlocking connections between a retainer ring and the outer race. An example of this type of prior art is illustrated in U.S. Patent No. 3,057,045 for a "Method Of Assembling Roller Bearings" issued in the name of Raymond G. Johnson on October 9, 1962. Johnson discloses a bearing whose inner retainer ring contains a radially outwardly extending flange which extends into a groove formed in the inner surface of the outer race.

other prior art patents disclose various means for limiting axial movement of the bearing assembly and its various com-

2 - ponents. An example of this type of prior art is illustrated in U.S. Patent No. 3,006,703 for "Needle Bearings" issued in the name of Emil Bensch on October 31, 1961. In FIG. 1, Bensch discloses the use of an annular or disc-like abutment mounted on a shaft to prevent axial displacement of the bearing cage.

Some problems with these prior art patents include the requirement to remove fasteners, such as individual pins, from the bearing assembly before the bearing can be used in nor- mal operation. In addition, the means for holding the bearing assembly together does not always provide adequate means for preventing axial movement of the bearing on the shaft and axial movement of various bearing assembly components relative to each other. The use of separate components to perform these two functions increases the overall cost of the bearing assembly.

The bearing assembly of the present invention overcomes these problems by providing a cage with an internal locking rib which interlocks with the inner race to prevent axial movement of the cage relative to the inner race. The inner race. makes an interference fit with the shaft on which it is mounted to prevent axial movement of the overall bearing assembly. The bearing assembly is well- suited for use in components having a bore whose inner diameter provides an outer raceway surface for the bearing assembly, such as a connecting rod or a gear bore.

Briefly described, the bearing assembly of this invention comprises an inner race member having an annular groove in its outer surface, and a cage-and-roller subassembly com- prising a cage having an annular flange or rib extending radially inwardly so as to extend into the groove of the inner race, thereby limiting axial movement of the cage-androller subassembly relative to the inner race. The inner race is mounted on a shaft with which it makes an interfer- ence fit, and the cage has an axial split which inhibits fretting corrosion.

This invention may be better understood by reference to the following detailed description and drawings in which:

FIG. 1 is a side sectional view in elevation of the cage and inner ring of the bearing assembly of the present invention; and FIG. 2 is a fragmentary view of the outer surface of the cage shown in FIG. 1/ showing the axial split in the cage.

In the various figures, like parts are referred to by like numbers.

Referring to the drawings, and more particularly to FIG. 1, bearing assembly 12 comprises an inner race or ring 20 and cage"and-roller subassembly 30. The subassembly consists of a cage 32 and multiple rollers 40 (see Fig. 2). Cage 32 has an annular flange or internal locking rib 33 projecting radially inwardly. Inner ring 20 has an annular groove 22 in its outer surface. When subassembly 30 and inner ring 20 are properly aligned, the locking rib 33 makes a loose fit in groove 22 so as to limit relative axial movement between inner ring 20 and the cage-and-roller subassembly 30.

Turning now to FIG. 2, cage 32 has multiple rollers 40, each of which is held in position by a pocket 36 in cage 32. Cage 32 also has an axial split 50 which allows the cage to 4 be spread open in the outward radial direction to facilitate the installation of the cage around the inner ring 20.

Additionally, axial split 50 helps reduce fretting corrosion and its associated problems. Fretting corrosion is the static wear of the inner ring raceway surface by rollers 40 when there is no relative movement between inner ring 20 and the cage 32, thereby causing rollers 40 to be stationary relative to ring 20. As a roller 40 remains in one spot relative to inner ring 20, the roller vibrates with the bearing assembly 12. This vibration causes a condition commonly referred to as false brinelle, whereby the roller causes excessive wear in one spot of the outer surface of inner ring 20, resulting in concave pitting which generally matches the radius of the roller 40.

The axial split 50 in cage 32 inhibits this fretting corrosion action in the following manner. Since cage 32 is a roll-riding cage, the rollers 40 are forced against the outer raceway surface (not shown) during normal operation. The normal vibratory motion of the bearing assembly 12 during normal operation is transmitted to the rollers 40 and cage 32, causing the cage to flex or "breathe". This flexing results in the precession of cage 32 relative to inner ring 20. This precession of cage 32 causes rollers 40 to precess along with the cage. Since the rollers 40 are no longer stationary relative to inner ring 20, the rollers tend to wear more evenly and the surface of the inner ring 20 also tends to wear more evenly, without the effects of fretting corrosion.

The thickness of inner ring 20 at the location of groove 22 30 is designed to provide adequate structural integrity of the ring while providing for an adequately deep groove 22 so as to ensure adequate axial retention between the groove and the internal locking rib 33. If groove 22 was too deep, the structural strength of inner ring 20 could be decreased below a tolerable level. Likewise, if internal locking rib 33 was made too large, in the radial direction, in order to accommodate a deep groove 22, the possibility of breaking either rib 33 or the cage while installing the cage on ring 20 would be too likely.

It should be noted that while rib 33 makes a relatively 10 loose fit in groove 22, the axial clearance between the rib and the sides of groove 22 is adapted to prevent the axial ends of the cage-and-roller subassembly 30 from contacting axially adjacent surfaces. Thus, the relative axial movement between inner ring 20 and subassembly 30 is limited by the contact between groove 22 and internal locking rib 33.

6

Claims

CLAIMS:

An antifriction bearing assembly comprising: an annular inner ring having an annular groove in the outer surface of said ring; and a. cage-androller subassembly around said inner ring, said subassembly comprising multiple rollers and an annular cage having multiple pockets, said pockets being adapted to accommodate said multiple rollers so as to limit outward radial motion of said rollers and said cage having an annular radially inwardly extending rib adapted to make a loose fit in said annular groove of said inner ring.
2. An antifriction bearing assembly according to claim 1, wherein said cage has an axial split allowing said cage to be spread apart radially outwardly so as to facilitate installation of said cage around said inner ring and so as to inhibit fretting corrosion of said bearing assembly.
3. An antifriction bearing assembly, substantially as hereinbefore described with reference to the accompanying drawing.

Pablished 1989 atThePatentOffice,State House. 6671 HiglhHolborn, London WC1R 4TP-Furtxier c)pies maybe obtamedfrom ThefttentOfftce. Wes Branch, St Mary Cray, Orpington. Kent BR5 3P.D. Printed by Multiplex technique 3 Itd, St Mary Cray, Kent, Con. 1187