Thrust bearing assembly with preload spring

Details Thrust bearing assembly with preload spring Thrust bearing assembly with preload spring

2001-08-22

2004-12-14

Graham, Matthew C. (Department: 3683)

Bearings

Rotary bearing

Antifriction bearing

C384S620000

Reexamination Certificate

active

06830380

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates generally to thrust bearings and, more particularly, to thrust bearings used with springs to provide preload and thrust bearings with enhanced flow of lubricant.
Many thrust bearing applications, for example, air conditioning compressors, rely upon thrust bearings to provide preload for rotors and shafts to maintain design clearances. Lubrication of such bearings may be provided by a refrigerant/lubricant mixture, which generally has inferior lubrication properties than pure lubricants. In most cases, the components of such thrust bearing are installed separately, directly into the compressor. In addition to being a tedious and expensive operation, this separate installation procedure introduces risks of contamination, component misalignment, and even omission of some thrust bearing components.
FIGS. 1 and 2
illustrate a thrust bearing configuration according to current practice, before and after application of an axial load, respectively. Such loads are applied during assembly of an air compressor to stabilize the axial position of the compressor shaft. In general, the environment of the thrust bearing consists of a housing
10
in which a stepped diameter or a snap ring
13
in a groove is situated to act as a support for the thrust bearing components. A spring washer
16
is positioned adjacent one of two thrust races
14
that are separated by rolling elements
15
that are guided by a bearing cage
11
.
An air conditioning compressor shaft
20
has a shoulder
12
against which one thrust race
14
rests, such that when a sufficient axial preload is applied to the compressor shaft, the spring washer
16
is compressed as illustrated in FIG.
2
. As can be seen in the Figure, the bearing cage
11
and the thrust races
14
are piloted on the compressor shaft
20
so that there is radial clearance
17
between the thrust races
14
and the housing
10
but little radial clearance
18
between the thrust races
14
and the shaft
20
. The arrows in
FIG. 2
indicate that the supply of refrigerant/lubricant mixture supplied to the clearance
18
is adequate, but the amount that reaches the clearance
17
is substantially reduced. This reduced refrigerant/lubricant supply may not provide the required amount of lubrication for protection of the thrust bearing from wear, overheating, and build-up of contaminant.
In addition to problems of inadequate flow of refrigerant/lubricant, thrust bearing performance in such applications may be degraded due to cross piloting of the thrust races
14
between the compressor shaft
20
and the housing
10
. This is apparent in
FIG. 2
, in which the retaining snap ring
13
, the spring washer
16
, and the thrust race
14
are in face-to-face contact. The thrust race that is piloted on the compressor shaft
20
is intended to rotate with the shaft, and the washer
16
and snap ring
13
are restrained by the housing
10
. The rotation of the thrust race
14
is frictionally resisted by the spring washer
16
, rotation of which, in turn, is frictionally resisted by the snap ring
13
. This piloting arrangement leads to increased wear between the components. In the worst case, the retaining snap ring
13
may be driven by the spring washer
16
to turn in the housing and eventually slip out of the groove in which it is installed due to wear. When combined with the inadequate lube flow already described, the build-up of wear contaminant in the thrust bearing progresses at an increasing rate and may lead to premature thrust bearing failure.
The foregoing illustrates limitations known to exist in present thrust bearing configurations. Thus, it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.
SUMMARY OF THE INVENTION
In one aspect of the present invention, this is accomplished by providing a thrust bearing assembly comprising two thrust races, a plurality of rolling elements between and against the two thrust races, for facilitating relative rotation of the thrust races about a common axis, and a spring washer. The spring washer is axially outward of the two thrust races for engaging a support surface and for applying a preload to a first of the two thrust races. Retention means retains the two thrust races, the rolling elements and the spring washer together as an assembly to facilitate handling and installation.
The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.


REFERENCES:
patent: 2891828 (1959-06-01), Winchell
patent: 3268279 (1966-08-01), Greby
patent: 3317014 (1967-05-01), Pitner
patent: 3934956 (1976-01-01), Pitner
patent: 3972574 (1976-08-01), Pitner
patent: 4313644 (1982-02-01), Dagiel
patent: 4462608 (1984-07-01), Lederman
patent: 4533263 (1985-08-01), McGuffie
patent: 4699530 (1987-10-01), Satoh et al.
patent: 4725153 (1988-02-01), Tsuru
patent: 4907899 (1990-03-01), Rhoads
patent: 4968157 (1990-11-01), Chiba
patent: 5199802 (1993-04-01), Shinohara et al.
patent: 5344241 (1994-09-01), Wells
patent: 5435655 (1995-07-01), Wells
patent: 6036373 (2000-03-01), Faass et al.
patent: 2022723 (1979-12-01), None
patent: 2147957 (1985-05-01), None
patent: 2248475 (1992-04-01), None
patent: 2250064 (1992-05-01), None

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