Auxiliary bearing centering device
An auxiliary bearing system may include an auxiliary bearing receiver housing and an inertia ring. The auxiliary bearing receiver housing may include an axial inner surface, a first radially extending surface, and a first arcuate surface extending therebetween. The inertia ring may include an axial outer surface, a second radially extending surface, and a second arcuate surface extending therebetween. The second arcuate surface may have a radial outer end adjacent the second radially extending surface and a radial inner end adjacent the axial outer surface. The inertia ring may define a first angle between the axis of rotation of the shaft and a first tangent at a first point on the second arcuate surface adjacent the radial outer end, and a second angle between the axis of rotation of the shaft and a second tangent at a second point on the second arcuate surface adjacent the radial inner end.
1. An auxiliary bearing system to support a rotating shaft, comprising:
an auxiliary bearing receiver housing including a first arcuate surface extending between a first radially extending surface of the auxiliary bearing receiver housing and an axial inner surface of the auxiliary bearing receiver housing; and
an inertia ring coupled to the rotating shaft, the inertia ring comprising:
an axial outer surface;
a second radially extending surface parallel to the axial outer surface;
a second arcuate surface extending between the axial outer surface and the second radially extending surface, the second arcuate surface having a radial outer end at or adjacent the second radially extending surface and a radial inner end at or adjacent the axial outer surface;
a first angle defined between the axis of rotation of the rotating shaft and a first tangent at a first point on the second arcuate surface at or adjacent the radial outer end; and
a second angle defined between the axis of rotation of the rotating shaft and a second tangent at a second point on the second arcuate surface at or adjacent the radial inner end, wherein
the first angle is greater than the second angle, and
the second arcuate surface is configured such that the auxiliary bearing receiver housing seats the inertia ring when the inertia ring contacts the auxiliary bearing receiver housing.
2. The auxiliary bearing system of claim 1 , wherein the auxiliary bearing receiver housing circumscribes the inertia ring, and a clearance is defined between the first arcuate surface and the second arcuate surface when the rotating shaft is supported by a primary bearing system.
3. The auxiliary bearing system of claim 2 , wherein the clearance is about 0.127 cm in an axial direction and the clearance is about 0.0508 cm in a radial direction.
4. The auxiliary bearing system of claim 1 , wherein a fillet radius of about 0.0762 cm is defined at or adjacent the radial outer end of the second arcuate surface.
5. The auxiliary bearing system of claim 1 , wherein a length of the second radially extending surface is about 0.381 cm.
6. The auxiliary bearing system of claim 1 , wherein an axial extent of the second arcuate surface is about 1.27 cm.
7. The auxiliary bearing system of claim 1 , wherein a radius of curvature of the second arcuate surface is about 5.08 cm.
8. The auxiliary bearing system of claim 1 , wherein the first arcuate surface and the second arcuate surface are configured such that a centering force is exerted on the rotating shaft when the rotating shaft is supported by the auxiliary bearing system.
9. The auxiliary bearing system of claim 1 , wherein the auxiliary bearing system further comprises a rolling element bearing including an inner ring coupled to the rotating shaft and an outer ring coupled to the inertia ring.
10. The auxiliary bearing system of claim 1 , wherein the auxiliary bearing system further comprises an inertia ring retaining nut configured to retain the inertia ring in the auxiliary bearing receiver housing.
11. The auxiliary bearing system of claim 1 , wherein the first arcuate surface and the second arcuate surface are configured such that, when a primary bearing system supporting the rotating shaft fails, the inertia ring contacts the auxiliary bearing receiver housing at a first contact zone, the first contact zone being at or adjacent the radial inner end of the second arcuate surface.
12. The auxiliary bearing system of claim 11 , wherein the first arcuate surface and the second arcuate surface are configured such that, subsequent to contacting the auxiliary bearing receiver housing, the inertia ring contacts the auxiliary bearing receiver housing at a second contact zone, the second contact zone being at or adjacent the radial outer end of the second arcuate surface.
13. The auxiliary bearing system of claim 12 , wherein, the first arcuate surface and the second arcuate surface are configured such that a radial clearance is defined between the first arcuate surface and the second arcuate surface at or adjacent the radial inner end of the second arcuate surface, when the inertia ring contacts the auxiliary bearing receiver housing at the second contact zone.
14. The auxiliary bearing system of claim 12 , wherein, the first arcuate surface and the second arcuate surface are configured such that the rotational axis of the rotating shaft is co-axial with the rotational axis of an auxiliary bearing of the auxiliary bearing system, when the inertia ring contacts the auxiliary bearing receiver housing at the second contact zone.
15. The auxiliary bearing system of claim 11 , wherein the first arcuate surface and the second arcuate surface are configured such that a radial clearance between the inertia ring and the auxiliary bearing receiver housing at or adjacent the radial outer end of the second arcuate surface is about 0.0127 cm to 0.0254 cm, when the inertia ring contacts the auxiliary bearing receiver housing at the first contact zone.
16. A rotor system, comprising:
a shaft;
a primary bearing system that supports the shaft during normal operating conditions; and
an auxiliary bearing system that supports the shaft when the primary bearing system fails, the auxiliary bearing system comprising:
an auxiliary bearing receiver housing including a first arcuate surface extending between a first radially extending surface of the auxiliary bearing receiver housing and an axial inner surface of the auxiliary bearing receiver housing; and
an inertia ring coupled to the shaft, the inertia ring contacting the auxiliary bearing receiver housing when the primary bearing system fails, the inertia ring comprising:
an axial outer surface;
a second radially extending surface parallel to the axial outer surface; and
a second arcuate surface extending between the axial outer surface and the second radially extending surface,
wherein the second arcuate surface is configured such that an angle between the rotational axis of the shaft and a tangent at a first point on the second arcuate surface at or adjacent the second radially extending surface is greater than an angle between the rotational axis of the shaft and a tangent at a second point on the second arcuate surface at or adjacent the axial outer surface.
17. The rotor system of claim 16 , wherein an axial extent of the second arcuate surface is about 1.27 cm.
18. The rotor system of claim 16 , wherein a fillet radius of about 0.0762 cm is defined at or adjacent a radial outer end of the second arcuate surface.
19. The rotor system of claim 16 , wherein a radius of curvature of the second arcuate surface is about 5.08 cm.
20. The rotor system of claim 16 , wherein the first arcuate surface and second arcuate surface are configured such that, when the primary bearing system fails, the second arcuate surface contacts the first arcuate surface adjacent the axial inner surface prior to contacting the first arcuate surface adjacent the first radially extending surface.
21. The rotor system of claim 20 , wherein the first arcuate surface and the second arcuate surface are configured such that, when the first arcuate surface contacts the second arcuate surface, a centering force is exerted on the shaft.
22. A method comprising:
providing an inertia ring coupled to a shaft, the inertia ring having an arcuate surface extending circumferentially thereon, a geometry of the arcuate surface being such that an angle between the rotational axis of the shaft and a tangent at a first point on the arcuate surface is greater than an angle between the rotational axis of the shaft and a tangent at a second point on the arcuate surface, the first point being at or adjacent a radial outer end of the arcuate surface and the second point being at or adjacent a radial inner end of the arcuate surface; and
extending an auxiliary bearing receiver housing circumferentially around the inertia ring such that a radial clearance and an axial clearance are defined between the inertia ring and the auxiliary bearing receiver housing.
23. The method of claim 22 , wherein a fillet radius of about 0.0762 cm is defined at or adjacent the radial outer end of the arcuate surface.
24. The method of claim 22 , wherein the inertia ring contacts the auxiliary bearing receiver housing at or adjacent the second point prior to contacting the auxiliary bearing receiver housing at or adjacent the first point, when a primary bearing system supporting the shaft fails.