Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
2000-03-01
2002-03-12
Footland, Lenard A. (Department: 3682)
Bearings
Rotary bearing
Antifriction bearing
C384S569000
Reexamination Certificate
active
06354744
ABSTRACT:
BACKGROUND OP THE INVENTION
The invention relates to bearings, end washers and securing end washers to inner rings of roller bearings.
While there are many ways to provide bearings with end washers, the need remains for securing end-washers with retainers that do not impede the smooth functioning of the bearings assembled on shafts. Prior art roller bearing devices have end washers which are generally retained by press forming the extended ends of the inner ring into a chamfer on the end washer. That method tends to distort the bore size or causes binding of the rollers. Alternatively, a soft split ring is used between the inner rings and the end washer to secure the end washer, which distorts the bore and becomes easily loose. However, needs exist for bearings with end washers easily secured thereon by retaining rings that allow for optimal use of the bearing.
The present invention fulfills that need as described in the ongoing specification.
SUMMARY OF THE INVENTION
The invention is described with reference to bearings, end washers and securing end washers to inner rings of roller bearings. However, the invention is applicable to any bearing in which washers are secured to outer surfaces of the bearings.
In one form of the invention, a bearing has an outer ring, an inner ring and rollers between the rings. The inner ring has axial outward extensions with stepped radially outward surfaces, which receive the radially outward extending end washers. Inward extending grooves are formed in the axial surfaces of the steps. Inner axially extending surfaces of the end washers have complementary grooves about twice as deep as the grooves in the inner ring ends.
To assemble the washer on the inner ring, a C-shaped external retaining ring is expanded into the washer groove, while the washer is slipped over the axially extending surface of the step on the outer end of the internal ring. The external retaining ring slides along the lateral surface of the step until it reaches the groove and springs inward into the groove. Half of the thickness of the external retaining ring fits in the groove. The outer half of the thickness remains in the groove in the inner wall of the washer, firmly locking the washer on the stepped outer end of the inner ring.
Preferably the external retaining ring has a rectangular cross-section, usually a square cross-section, with a width that is slightly less than widths of the grooves, and with a radial height which is about twice the depth of the groove in the inner ring and slightly less than the depth of the groove in the central surface of the washer. The external retaining rings are made of spring steel and preferably have an inner diameter commensurate with the inner diameter of the groove on the extended end of the inner ring.
A tapered end washer installation plug is inserted in an end of the inner ring so that the maximum dimension of the tapered end is adjacent the end of the axially extending surface in the outer end of the inner ring. The tapered surface extends outward and slopes inward. An external retaining ring is partially placed in the groove of an end washer, and the end washer and retaining ring are placed on the tapered surface of the installation plug. Pushing the washer axially toward the inner ring expands the retaining ring until it is fully within the groove in the central surface of the washer. Continually pushing the washer toward the inner ring transfers, end washer and the retaining ring from the tapered wall of the installation plug to the axial surface of the stepped end of the inner ring. Pushing the washer to its home position against the radial wall of the step aligns the retaining ring with the groove in the axially extending wall of the step. The retaining ring springs into the groove, leaving part of the retaining ring in the washer groove and holding the washer firmly.
Usually two end washers are so installed on extended ends of an inner ring. Washers may be installed on any types of bearings, including a needle roller bearing. In the needle roller bearing installation the washers hold the outer rings in place and also retain the rollers. Outer ends of the washers fit within seals installed in recesses in the axial faces of the outer rings. The annular seals are preferably made of, but not limited to, acetal resin, nylon, hytrel or any other suitable material. The seals have an annular rim which fits between a radially extending inner surface of the washer and a radially extending surface in the outer ring recess. An outer flange of the seal fits between the axially extending outer surface of the washer and an axial surface of the recess. A sloped lip extends radially and axially outward from an inner end of the seal flange to fit tightly within the recess. The washers hold the outer rings in place, and also trap needle rollers between the outer surface of the inner ring and the inner surface of the outer ring. The outer ring, inner ring and end washers are preferably made of steel, and the seal is made of acetal resin or other suitable material. The bearing is prepacked with grease and allows rolling of the inner ring with respect to the outer ring, such as when a shaft is positioned in the inner ring.
The outer surface of the outer ring has a crown radius to allow turning of the outer ring in a seat for maintaining bearing and shaft alignment.
The invention is used for securing end washers to any bearing, and is not limited to roller bearings.
These and further and other objects and features of the invention are apparent in the disclosure, which includes the above and ongoing written specification, with the claims and the drawings.
REFERENCES:
patent: 1803966 (1931-05-01), Gibbons
patent: 2198376 (1940-04-01), Cederberg
Creighton Wray James
Footland Lenard A.
Narasimhan Meera P.
Roller Bearing Company of America, Inc.
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