Oil pump cavitation relief
AssigneeCaterpillar Inc.
InventorDavid J. Beatty
Life of this patent
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Abstract
A variable displacement pump has a fluid passageway formed through a swash plate fluidly communicating a piston chamber with a drive shaft chamber not later than when the piston chamber comes into open fluid communication with a valve blcok resident inlet port to prevent erosion of the swash plate and the valve block about the inlet port. Secondary port portions of reduced flow area per unit rotation communicate with and circumferentially lead primary port portions of greater flow area per unit rotation.
Claims9
In a variable displacement pump having a drive shaft positioned within a first chamber, a swash plate having a control surface, a plurality of pistons disposed in respective piston chambers formed in a rotatable piston block and being in engagement with said control surface, and a valve block having an inlet and an outlet port which are each sequentially communicatable with each piston during piston rotation about an axis A, each piston having a passageway providing fluid communication between a respective piston chamber and the control surface, the improvement comprising:
- said swash plate having a passageway for providing fluid communication between the first chamber and the piston chamber, said swash plate passageway having a leading edge;
- and
- each of said inlet and outlet ports having a secondary portion and a primary portion and each of said portions having a leading edge, each of said primary portions having a respective flow area per unit rotation about axis A at its leading edge of a first preselected magnitude and each of said secondary portions having a respective flow area per unit rotation about axis A at its leading edge of a second preselected magnitude, said second preselected magnitude being less than said first preselected magnitude.
Dependencies are inferred from the claim text.