Skew limiting bearing cage
A rolling element bearing assembly includes a rolling element bearing assembly cage for spacing a plurality of rolling elements during operation of the rolling element bearing assembly about a central rotation axis. The cage includes a first axial end ring, a second axial end ring, and a plurality of bridges extending between the first axial end ring and the second axial end ring. The plurality of bridges defining roller pockets therebetween. At least one of the plurality of bridges includes a Rayleigh step array disposed on a surface thereof. The surface facing an interior of the roller pocket.
1. A rolling element bearing assembly cage for spacing a plurality of rolling elements during operation of the rolling element bearing assembly about a central rotation axis, the cage comprising:
a first axial end ring;
a second axial end ring; and
a plurality of bridges extending between the first axial end ring and the second axial end ring, the plurality of bridges defining a corresponding plurality of roller pockets therebetween, at least one of the plurality of bridges including a Rayleigh step array disposed on a surface thereof, the surface facing an interior of the roller pocket.
2. The cage of claim 1 , wherein the roller pocket which the Rayleigh step array faces includes four quadrants, wherein the Rayleigh step array is disposed within a first of the quadrants, and wherein each of the other three quadrants includes a Rayleigh step array.
3. The cage of claim 1 , wherein each of the plurality of roller pockets is tapered, and wherein the plurality of tapered roller pockets are configured to receive tapered rolling elements therein.
4. The cage of claim 1 , wherein each of the plurality of roller pockets includes a Rayleigh step array.
5. A rolling element bearing assembly comprising a cage according to claim 1 , the rolling element bearing assembly further comprising:
an inner ring;
an outer ring; and
a plurality of rolling elements situated between the inner and outer rings and spaced circumferentially from each other by the plurality of bridges of the cage, the plurality of rolling elements configured to facilitate relative rotation between the inner ring and the outer ring.
6. A cage for spacing a plurality of rolling elements in a rolling element bearing assembly containing a working fluid, the cage comprising:
a first axial end ring;
a second axial end ring;
a central rotation axis extending centrally through the first axial end ring and the second axial end ring; and
a plurality of roller pockets spaced circumferentially about the cage, each of the plurality of roller pockets configured to receive a rolling element therein,
wherein at least one of the plurality of roller pockets includes a Rayleigh step array that generates a hydrodynamic force within the working fluid in response to a skew angle between a rotational axis of the rolling element within the roller pocket and the central rotation axis.
7. The cage of claim 6 , wherein the roller pocket having the Rayleigh step array includes four quadrants, and wherein each of the four quadrants includes a Rayleigh step array.
8. The cage of claim 7 , wherein the Rayleigh step arrays in adjacent quadrants have opposite geometric step directionality.
9. The cage of claim 8 , wherein each Rayleigh step array includes a plurality of distinct Rayleigh step geometries.
10. The cage of claim 9 , wherein each Rayleigh step geometry within a Rayleigh step array has the same geometric step directionality.
11. The cage of claim 6 , wherein each of the plurality of roller pockets includes a Rayleigh step array.
12. A rolling element bearing assembly comprising a cage according to claim 6 , the rolling element bearing assembly further comprising:
an inner ring;
an outer ring; and
a plurality of rolling elements disposed within the plurality of roller pockets, the plurality of rolling elements configured to facilitate relative rotation between the inner ring and the outer ring.
13. The rolling element bearing assembly of claim 12 , wherein the plurality of rolling elements are tapered rolling elements, and wherein the plurality of roller pockets are tapered roller pockets.
14. The rolling element bearing assembly of claim 12 , wherein each of the plurality of roller pockets includes a Rayleigh step array.
15. The rolling element bearing assembly of claim 12 , wherein
a first rolling element of the plurality of rolling elements is disposed within the at least one of the plurality of roller pockets,
the Rayleigh step array is a first Rayleigh step array of a plurality of Rayleigh step arrays, the first Rayleigh step array is configured to generate a first hydrodynamic force on the first rolling element when the outer ring is rotated relative to the inner ring in a first direction, and
a second Rayleigh step array of the plurality of Rayleigh step arrays is configured to generate a second hydrodynamic force on the first rolling element when the outer ring is rotated relative to the inner ring in a second direction, opposite the first direction, the second hydrodynamic force acting in a different direction than the first hydrodynamic force.
16. The rolling element bearing assembly of claim 15 , wherein the first hydrodynamic force acts on the first rolling element in a different location than the second hydrodynamic force.
17. A method of operating a rolling element bearing assembly, the method comprising:
providing an inner ring, an outer ring, a plurality of rolling elements disposed between the inner ring and the outer ring, and a cage configured to circumferentially space the plurality of rolling elements about the rolling element bearing assembly, the cage including a plurality of roller pockets in which the plurality of rolling elements are located, at least one of the plurality of roller pockets including a Rayleigh step array;
imparting relative rotation between the outer ring and the inner ring to set the plurality of rolling elements in rolling contact with the outer ring and the inner ring, the rotation imparting skew to at least one of the plurality of rolling elements; and
in response to the skew of the at least one of the plurality of rolling elements, generating a skew counteracting hydrodynamic force on at least one of the plurality of rolling elements with the Rayleigh step array.
18. The method of claim 17 , wherein each of the plurality of roller pockets includes a Rayleigh step array, each of the Rayleigh step arrays generating a skew counteracting hydrodynamic force on the plurality of rolling elements in response to the skew of the plurality of rolling elements.
19. The method of claim 17 , wherein the outer ring includes a rib configured to secure the plurality of rolling elements between the outer ring and the inner ring, the rib imparting the skew to the plurality of rolling elements during rotation.