Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
2000-03-02
2001-09-11
Hannon, Thomas R. (Department: 3682)
Bearings
Rotary bearing
Antifriction bearing
C384S510000, C384S537000
Reexamination Certificate
active
06287013
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns a chiplessly shaped ball bearing, particularly an angular contact ball bearing for a steering shaft of an automotive vehicle, comprising an outer ring, an inner ring and bearing balls which are in rolling contact with raceways of the outer and the inner ring, a falling-apart of the bearing being prevented by a radially outward oriented projection of the inner ring that overlaps an inner diameter of the outer ring.
BACKGROUND OF THE INVENTION
Such chiplessly shaped angular contact ball bearings that can take up axial forces only in one direction and therefore have to be positioned against a second bearing are preferentially used as steering bearings because they have a very small moment of friction, a relatively high rigidity and are simple to mount and economic at the same time.
These angular contact ball bearings made up of the two bearing rings have to be retained inseparably together for transport and for assembly at the customer's site. In a solution offered in the document DE-GM 69 06 278, the inner bearing ring comprises an extended region that is folded over around the outer bearing ring in radial direction. This folding-over can be achieved, for example, by rolling.
A drawback of this is that the bearing can only be hardened in the region of the raceways, because, otherwise, it is not possible to fold over the extended inner ring. However, a partial hardening of a bearing is always more complicated than a hardening of the entire bearing.
OBJECTS OF THE INVENTION
It is an object of the invention to create a safety device for a chiplessly made ball bearing which renders the ball bearing inseparable without disadvantageously influencing the cost of manufacturing and assembly of the bearing.
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 the projection is configured in the form of circumferentially uniformly spaced resilient retaining tabs which, as viewed in longitudinal cross-section, comprise an axially outer section and an axially inner section, which axially outer and inner sections are disposed angularly relative to each other and separated by a vertex, a diameter of the retaining tabs is largest at the vertex, and a diameter of the axially outer section of the retaining tabs is smaller than an inner diameter of the outer ring.
These inventive measures enable, in a simple manner, a reliable coherence of the ball bearing as well as a simple assembly because the axially outer section of the retaining tabs assures that the outer ring is lodged and guided during assembly. When the two bearing rings are slipped axially onto each other, the resilient retaining tabs of the inner ring are pressed radially inwards by the outer ring and snap into their original position when the vertex has passed through so that the bearing is then held reliably together. The overlap of the retaining tabs can be chosen to be large enough to prevent a falling-apart of the bearing during transportation with certainty. An excessively large overlap as encountered in the prior art which can result in a breaking-off of conventional retaining tabs does not present any drawbacks in the present invention because the retaining tabs of the invention are very flexible.
According to further features of the invention, the axially inner and outer sections of the retaining tabs may be oppositely inclined to form a roof shape or they may have a curved configuration. These are equal solutions and the choice depends solely on the available manufacturing technology.
According to another feature of the invention, the bearing balls are arranged in a cage. In contrast to a full-complement set of balls, the use of a cage reduces fluctuations in the moment of friction.
According to a final feature of the invention, the ball bearing is subjected to a heat treatment to improve its mechanical properties. The individual components of the bearing may be heat-treated prior to the assembly of the bearing which means that snapping is effected in the hardened state. However, the opposite procedure is just as feasible, i.e. the bearing is snapped together in the unhardened state and then hardened as a whole to achieve an improvement of its mechanical properties.
The invention will now be described in further detail with reference to an example of embodiment represented in the appended drawings.
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Loncar Peter
Nutzel Reinhold
Bierman, Muserlian and Lucas
Hannon Thomas R.
Ina Walzlager Schaeffler
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