Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
1999-03-02
2001-03-27
Marmor, Charles A (Department: 3681)
Bearings
Rotary bearing
Antifriction bearing
C384S572000, C384S580000
Reexamination Certificate
active
06206576
ABSTRACT:
FIELD OF THE INVENTION
A cage for cylindrical rolling elements, more particularly a needle roller cage, whose side rings are connected to each other by crossbars to form pockets, said crossbars being profiled to hold each rolling element on either side of a pitch circle by crossbar edges which are parallel to axes of the rolling elements, said side rings comprising inwardly directed convexities against which the rolling elements bear by end faces.
BACKGROUND OF THE INVENTION
A cage of this type described in U.S. Pat. No. 5,391,005 has an approximately M-shaped cross-sectional profile and comprises two side rings which are joined to each other by circumferentially equally spaced crossbars. The crossbars, which together with the side rings define pockets for the reception of the rolling elements, are divided into a number of sections, viz., two side sections, one center section and two inclined connecting sections, that is to say, they are bent inwards towards the center of the bearing to extend beyond the pitch circle. The outward and inward retention of the rolling elements is effected by the sections of the crossbars situated outside and inside the pitch circle, respectively.
In such needle roller cages, the length of the needle rollers and the width of the cage are matched to each other so that the needle rollers extend with their axial dimension almost from side ring to side ring to prevent the ends of the needle rollers from tilting out of the pockets. Under certain technical conditions, however, for example, in the case of large transition radii on stepped shafts, it can become necessary to equip such cages with shorter needle rollers because, otherwise, the needle rollers would come into rolling contact with the transition radii of the transition region of the shaft. But if such a cage is equipped with shorter needle rollers, these could eventually tilt over the crossbars and slip beneath the stamped retention elements and thus fall out of the pockets. In the state of the art, this is prevented by the fact that the end faces of the rolling elements bear against radially inwards directed convexities of the side rings.
A drawback of this cage is that the convexities permit only an insufficient contact of the end faces of the needle rollers. This is due to the fact that the convexities, because of their rigid connection to the side rings, do not comprise a plane-parallel contact surface, i. e. a surface contact is not possible between the convexity and the end face of the needle roller but, at the best, only a linear contact.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to improve a generic bearing cage so that an improved contact between the convexity and end faces of the needle rollers is possible.
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, between the crossbars in peripheral direction, the side rings comprise a slot which is spaced from the ends of the pockets so that a section of material is formed which is retained by two adjacent crossbars and which, in a radially inwards bent state, constitutes the convexity. Due to this modified connection of the convexity to the side ring, the convexity retains a plane-parallel contact surface even in the radially inwards bent state so that the bearing cage offers improved contact for the end faces of the needle rollers.
According to a further feature of the invention, the radial dimension of the slot is enlarged. By this is meant that an empty space is formed in the side rings between these and the convexities which permits an improved flow of lubricant through the bearing and thus decisively improves the friction behavior of the bearing.
According to a further proposition of the invention, the side rings comprise radially inwards directed flanges which improve the stability of the cage.
Finally, the novel manner of connecting the convexities can be used advantageously both in radial as well as in axial cages.
REFERENCES:
patent: 1232523 (1917-09-01), Folk
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patent: 3038767 (1962-06-01), Greby
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patent: 3365775 (1968-01-01), Cavagnero
patent: 3482891 (1969-12-01), Evangelista et al.
patent: 4522516 (1985-06-01), Neese
patent: 5391005 (1995-02-01), Alling
patent: 5567059 (1996-10-01), Weigand et al.
patent: 376378 (1923-05-01), None
patent: 1941894 (1966-07-01), None
patent: 4444449 (1995-08-01), None
Bierman, Muserlian and Lucas
INA Walzlanger Schaeffler oHG
Marmor Charles A
Rodriguez Saul
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