Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
1999-11-30
2001-07-17
Hannon, Thomas R. (Department: 3682)
Bearings
Rotary bearing
Antifriction bearing
Reexamination Certificate
active
06261005
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns a rolling bearing cage for cylindrical or needle rollers, said cage being made of a resilient plastic and comprising at at least one peripheral point, an axially extending gap formed by a first cage end and a second cage end which is spaced from the first cage end, each of the first and the second cage ends comprising at least one projection and at least one recess, said recess and projection having complementary shapes, and as viewed in axial direction, the recess and the projection partially engage each other, and as viewed in peripheral direction, the recess and the projection partially overlap each other.
BACKGROUND OF THE INVENTION
A rolling bearing cage of the pre-cited type is known from DE 40 07 452 A1. The two ends of the cage are separated by an axial gap and each end comprises two projections which cooperate with recesses on the other cage end. The projections are configured so that, as viewed in axial direction, they engage each other partially and as viewed in peripheral direction, they overlap each other partially. This assures that the cage is fixed both in axial and in radial direction i.e., the two cage ends cannot be displaced relative to each other in axial or in radial direction. However, in peripheral direction, the cage ends are displaceable relative to each other, so that a compression of the cage is stopped when the projections and the opposing recesses bear against one another. An expansion of the cage, in contrast, is not limited. This can be a drawback during assembly because it is possible for several cages to get entangled with one another. Furthermore, assembly is also rendered more difficult because an excessive expansion of such a cage would require more force to insert it into a bore of smaller diameter.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to improve a cage of the pre-cited type so that the above drawbacks are eliminated by providing that although the cage ends are displaceable relative to each other in peripheral direction, their displacement in both peripheral directions is still limited.
This and other objects and advantages of the invention will become obvious from the following detailed description.
SUMMARY OF THE INVENTION
The invention achieves the above objects by the fact that, as seen in a radial top view of the gap, limiting surfaces of the projection and the recess situated opposite each other in axial direction are inclined relative to end faces of the cage so that a dovetail profile is formed which enables the first and the second cage end to be displaceable relative to each other in peripheral direction, so that an expansion of the cage is stopped when the limiting surfaces situated opposite each other in axial direction bear against each other and a compression of the cage is stopped when limiting surfaces of the projection and the recess situated opposite each other in peripheral direction bear against each other.
The cage ends of the rolling bearing cage of the invention comprise a projection and a recess which are configured so that the projection is situated within the recess and extends in peripheral direction. Due to the fact that the projection and the recess engage each other in axial direction, a relative axial displacement of the two cage ends is prevented. In a radial top view of the gap region of the cage, the two cage ends are situated next to each other but the projection and the recess, and the projections of the two cage ends overlap each other so that it is assured that the two cage ends are retained in one and the same peripheral plane, that is to say that they cannot slip radially over each other. Finally, the dovetail profile enables the cage ends to move relative to each other in peripheral direction but only to a limited extent. The compression of the cage is terminated when the projection has sunk completely into the associated recess i.e. when limiting surfaces of the projection and the recess parallel to the cage axis bear directly against each other. The expansion of the cage is likewise possible only to a limited extent, viz., only till the inclined limiting surfaces of the projection and the recess situated opposite each other in axial direction come to bear directly against each other.
In a preferred embodiment of the invention, the first cage end comprises two outer projections formed directly adjoining the end faces of the cage and corresponding to two opposing recesses formed in the second cage end. These two outer projections of the first cage end are defined by a recess which corresponds to two spaced-apart projections of the second cage end. This symmetric configuration of the two cage ends enables a uniform mutual support thereof and thus prevents any bracing that may otherwise occur.
According to a further feature of the invention, the overlap between the projections of the first and second cage ends is formed by a step of each projection in that a step of the projection of the first cage end accessible radially from the outside corresponds to a step of the projection of the second cage end accessible radially from the inside, and vice versa.
The projections of the second cage end engage the recess of the first cage end which is formed as a step, whereby the projections are supported so that a radial offset between the two cage ends is prevented while a relative movement of the cage ends in peripheral direction is permitted.
A radial offset between the cage ends may also be prevented by realizing the overlap between the projections by providing a groove in the projection of the first cage end, which groove is engaged by an associated elevation arranged on the projection of the second cage end. This groove may have a rectangular, triangular or semi-circular cross-section.
Finally, according to still another advantageous feature of the rolling bearing cage of the invention, the thickness of the region of overlap does not exceed the thickness of the rolling bearing cage.
REFERENCES:
patent: 3399008 (1968-08-01), Farrell et al.
patent: 5033876 (1991-07-01), Kraus
patent: 5178474 (1993-01-01), Muntnich et al.
patent: 3041860 (1982-06-01), None
patent: 3411493 (1984-10-01), None
patent: 3928913 (1990-03-01), None
patent: 4007452 (1991-09-01), None
patent: 4337948 (1995-05-01), None
Beck Tino
Rost Herbert
Staudigel Erwin
Wildeshaus Walter
Winkler Manfred
Bierman. Muserlian and Lucas
Hannon Thomas R.
Ina Walzlager Schaeffler OHG
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