Combined radial and thrust bearing

The combined radial and thrust bearing has an annular series of rollers in the annular space between an inner race and an outer race for taking radial forces. The thrust bearing part includes a pair of axially spaced apart washers at each longitudinal end of the bearing. An annular series of balls are located in the annular space between the washers. The ball bearing retainer is dimensioned so that a very close clearance exists with the two washers in order to maintain a very small labyrinth clearance for sealing purposes.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates in general to a radial and thrust bearing 
assembly, more specifically to a roller radial and ball thrust bearing 
assembly that includes a labyrinth seal. 
2. Description of the Prior Art 
In an early design disclosed in U.S. Pat. No. 1,296,827, patented Mar. 11, 
1919 by L. W. Lyons and J. Wills, a radial roller bearing which uses load 
carrying rollers that are spaced apart by smaller rollers instead of by 
cage means, incorporates a pair of concentric, easily replaceable, tubular 
metal sleeves for inner and outer races. Roller limiting collars axially 
abut the inner race on each side of the raceway. Each collar includes a 
flange which projects radially beyond the inner surface of the sleeve to 
form an endwise limiting means for the rollers. Radially disposed, 
parallel, planar housing collars or washers, locate at their outer 
peripheries against annular shoulders on the outer race. At their inner 
peripheries, the washers closely approach the roller limiting collars 
adjacent to the outer surface of the flanges, without forcibly touching or 
having any frictional contact with the collar or flanges. Set screws 
through the outer race, bear on the outer periphery of each washer to hold 
it in place. Mounted on the bearing shaft, held in place by split ring, 
shoulder, or other means, are end members of a pair of ball thrust 
bearings. The balls run between raceways located on the end members and on 
the outer surfaces of the washers. 
This arrangement provides a combination radial and thrust bearing with 
closely sealing ends. 
In another combination roller radial and ball thrust bearing, disclosed by 
W. W. Murphy in U.S. Pat. No. 3,168,359 patented Feb. 2, 1965, an enlarged 
portion of a shaft forms an inner race for the radial bearing. A sheet 
metal collar which includes the outer race for the radial bearing, 
includes inwardly turned, radially disposed, flanges. Caged rollers, which 
ride on the enlarged portion of the shaft, are axially contained by the 
inner faces of thrust collars located on the shaft at each end of the 
inner race. The thrust collars rest against, and extend above, annular 
shoulders formed at each end of the race by the difference between the 
major diameter of the race and the outer diameter of the shaft. The outer 
faces of the thrust collars and the inner faces of the radially disposed 
flanges include races for caged balls, establishing thrust bearings which 
resist axial movement in both directions, of the shaft with respect to the 
collar. 
A resiliently mounted combination radial and axial thrust bearing is 
disclosed in U.S. Pat. No. 4,109,977, patented Aug. 29, 1978, by Gerard 
Staphan. The bearing holds a rotating shaft within a bore by way of 
insertion of the outer race, within a resilient sleeve of elastomeric 
material that lines the bore. The outer race of the radial bearing, 
extending the width of the bearing rollers, abuts axially at one end by 
means of an inwardly turned radially oriented annular wall, against a 
shoulder in the resilient sleeve. The other end of the cylindrical sleeve 
portion of the outer race extends free of contact with the elastomer, into 
an annular cavity within the resilient sleeve. The inner race of the 
radial bearing extends from a position under the wall, where it abuts 
axially against a shoulder on the shaft, to a position beyond the width of 
the rollers, and ends with an outwardly turned radially oriented wall. The 
inner surface of the outwardly turned wall includes a race for a thrust 
bearing. The other race for the thrust bearing is provided by a radially 
oriented annular wall which axially abuts the free end of the outer race, 
and which is held in place against the resilient sleeve by an outwardly 
turned axially oriented cylindrical flange. 
SUMMARY OF THE INVENTION 
The present invention provides a combination radial and thrust bearing in 
which there is a radial bearing having an inner and outer race, and an 
inner and outer raceway spaced to form an outer-inner raceway annulus for 
bearing rolling members. An annular series of bearing rolling members are 
in the annulus. 
A first, radially disposed washer, is located by an outer periphery of the 
inward face, against an axially-receiving stop face on the outer race. The 
outward face of the washer includes a raceway for a thrust bearing. 
A second, radially disposed washer is coaxial with and axially spaced from 
the first washer, and has an inward facing raceway opposed to the raceway 
on the first washer, forming an annulus between &:he raceways for rolling 
members of the thrust bearing. 
The second washer includes a first, axially oriented, inward projecting 
member which is located radially outwardly from the bearing rolling 
members. 
The second washer further includes a second, axially oriented, inward 
projecting member which is located radially inwardly from the bearing 
rolling members. The second member is fixedly mounted on the inner race of 
the radial bearing. 
Bearing rolling member retainer means for spacing the members apart, 
includes a circumference and an annular outer surface that is in close 
proximity to the second washer, and an annular inner surface that is in 
close proximity to the first washer, for forming a seal. Further seal is 
provided by the first inward projecting member being in close proximity to 
the first washer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The invention will now be described by way of example, and is not limited 
in its application to the details of construction and arrangement of parts 
illustrated in the drawings, since the invention is capable of other 
embodiments. The phraseology or terminology employed is for the purpose of 
description only and not of limitation. 
Bearing 20, shown in FIG. 1, includes radial bearing outer race 22 with 
raceway 24, inner radial bearing race 26 with raceway 28. Bearing rollers 
32 in retainer 34 locate radially between the raceways, and axially 
between each of the two inner washers 36. On each end of the bearing, 
inner washer 36 rests against bearing end facing surface 40, and locates 
radially against radially inward facing surface 42 of shoulder 44 of outer 
race 22. Inner washer 36 does not contact inner race 26. 
Washer 46 at each end of the bearing, outboard of and facing toward inner 
washer 36, abuts against bearing end surface 50 of inner race 26 by way of 
flange 52 which spaces thrust bearing raceway 54 of the washer from 
raceway 56 of inner washer 36. Washers 46 are "C" shaped in cross-section. 
Balls 60 and retainer 62 run between raceways 54 and 56, and radially 
within the confines of inwardly turned flanges 64 and 52 of outer washer 
46. Retainer 62 has a width and outer diameter that establishes a small 
labyrinth clearance 66 between the retainer and inner washer 36, and 
adjacent inner faces 70 and 72 of outer washer 46, for sealing of the 
bearing. 
Outer washer 46 is fixedly installed on inner race 26 by press fit against 
the radially outward facing surface of inner race 26. In lieu of press 
fit, post welding or other fastening means may be used to appropriately 
secure the washer on the inner race. 
Inner race 26 is independent of the shaft (not shown) on which bearing 20 
locates. This need not be the case, however. 
Bearing 80, FIG. 2, designed to accept heavier thrust loads than bearing 
20, includes radial outer race 82, radial inner race 86, and raceways 84 
and 90 for rollers 92 and retainer 94. Radial inner race 86 is a part of 
rotatable shaft 98. 
Inner washer 96 limits axial displacement of rollers 92 at each end of 
raceway 84. Washer 96 includes grooved raceway 102 of a thrust bearing 
that includes balls 104, retainer 106, and grooved raceway 108 of outer 
washer 110. The grooves contribute to support against additional thrust 
load. Washer 110 is preferably press fit onto intermediate raised diameter 
surface 112, and against radial face 114 of annular step 116. Inner race 
90 is located on the fully raised diameter of shaft 98. 
Small labyrinth clearance 118 is provided by retainer 106, sized to fit 
closely spaced to adjacent surfaces on inner washer 96 and outer washer 
110. 
Rigid, unyielding raceways in a thrust bearing necessitate some small 
clearance between the ball and raceway in order to avoid binding of the 
ball between the raceways. Binding with close fit in such a bearing can 
occur from slight distortion of surfaces caused by temperature or loading. 
Axial play, therefore, can occur between the outer and inner radial races, 
by an amount equal to the clearances between the thrust bearing ball and 
raceways. 
This can be overcome by bearing 120 shown in FIG. 3. Bearing 120 resists 
axial play between radial outer race 122 and inner radial race 124. In 
bearing 120, inner washer 126 raceway 128 is preloaded by washer 130, 
which is "C" shaped in cross-section, by way of outer washer raceway 132 
and ball 134. Inner washer 126 is made from a resilient or spring-like 
material. Although washer 126 is shown deflected to an inward angle, it 
may be shaped so that it is vertical or angled outward under preload. One 
way to effect this is to make inner washer 126 from a Belleville type 
washer. 
Use of the preloaded washer has no detrimental effect upon the labyrinth 
clearance 136 as long as the width of retainer 138 is set to allow for 
minimum spacing that is expected to occur between the two washers at 
surfaces adjacent to the retainer. 
Washer stiffness and clearance between the outer washer and the radial 
outer race may be selected to permit spring controlled limited axial 
displacement between the radial bearing inner and outer races for shock 
resistance or other desirable purposes. With preload, axial clearance in 
the bearing resulting from the working tolerances of the parts is also 
minimized. 
It is not intended that details of the embodiments described be limitations 
upon the scope of the invention which shall be defined by the following 
claims.