Back to results
US 2015/0316040 A1Published application
Stress Reduction in Hydrostatic Cradle Bearing
AssigneeCaterpillar Inc.
InventorsMarek Golebiowski, Christopher W. Pruess
Life of this patent
Estimating the term…
Abstract
In a piston pump assembly, cradle bearings support a swash plate on an inner surface of a housing assembly. The cradle bearing and/or the corresponding portion of the housing inner surface may have undercut portions allowing deflection of an inward portion of the cradle bearing when the swash plate is subjected to pressure forces from hydraulic fluid compressed within pump cylinders by the pump pistons. Deflection of the cradle bearings allows increased contact pressure to be further distributed across the engaging surfaces of the swash plates and the cradle bearings.
Claims20
A cradle bearing for use with a swash plate in a piston pump assembly, the cradle bearing comprising:
- a bearing outer end surface;
- a bearing inner end surface disposed opposite the bearing outer end surface and spaced from the bearing outer end surface by a bearing width;
- a bearing concave inner surface extending from the bearing outer end surface to the bearing inner end surface;
- and
- a bearing convex outer surface disposed opposite the bearing concave inner surface and extending from the bearing outer end surface to the bearing inner end surface, the bearing convex outer surface comprising:
- a housing engaging surface extending from the bearing outer end surface toward the bearing inner end surface, wherein the cradle bearing has an engagement thickness from the bearing concave inner surface to the housing engaging surface of the bearing convex outer surface, and
- an undercut surface extending from the bearing inner end surface toward the bearing outer end surface to a point of transition with the housing engaging surface, wherein the cradle bearing has an undercut thickness from the bearing concave inner surface to the undercut surface of the bearing convex outer surface that is less than the engagement thickness of the cradle bearing.
4 more elements
A piston pump assembly for a piston pump, comprising:
- a piston housing having a pair of oppositely disposed housing concave surfaces;
- a swash plate having a pair of oppositely disposed swash plate convex surfaces, each of the pair of oppositely disposed swash plate convex surfaces corresponding to one of the pair of oppositely disposed housing concave surfaces;
- and
- a pair of cradle bearings with each of the pair of cradle bearings corresponding to and disposed between one of the pair of oppositely disposed swash plate convex surfaces and a corresponding housing concave surface to facilitate rotational motion of the swash plate relative to the piston housing, each of the pair of cradle bearings having a bearing concave inner surface having a complimentary shape to the pair of oppositely disposed swash plate convex surfaces, a housing engaging surface disposed opposite the bearing concave inner surface by a cradle bearing thickness and having a complimentary shape to the pair of oppositely disposed housing concave surfaces, and an undercut surface disposed opposite the bearing concave inner surface by an undercut thickness and extending from a bearing inner end surface toward a bearing outer end surface to a point of transition with the housing engaging surface, wherein the undercut thickness is less than the cradle bearing thickness to define a gap between the undercut surface the corresponding housing concave surface.
1 more element
A piston pump assembly for a piston pump, comprising:
- a piston housing having a pair of oppositely disposed housing concave surfaces;
- a swash plate having a pair of oppositely disposed swash plate convex surfaces, each of the pair of oppositely disposed swash plate convex surfaces corresponding to one of the pair of oppositely disposed housing concave surfaces;
- and
- a pair of cradle bearings with each of the pair of cradle bearings corresponding to and disposed between one of the pair of oppositely disposed swash plate convex surfaces and a corresponding housing concave surface to facilitate rotational motion of the swash plate relative to the piston housing, each of the pair of cradle bearings having a bearing concave inner surface having a complimentary shape to the pair of oppositely disposed swash plate convex surfaces, and a bearing convex outer surface disposed opposite the bearing concave inner surface and having a complimentary shape to the pair of oppositely disposed housing concave surfaces, wherein each housing concave surface and corresponding bearing convex outer surface define an undercut gap there between extending outwardly from a bearing inner end surface to an undercut transition portion beyond which the housing concave surface and the housing engaging surface face and engage.
1 more element
Dependencies are inferred from the claim text.