Patent ID: 9212656
Filing Date: 2015-12-15
Classification: F04B

Abstract:
1. A method for lubricating a piston-to-shoe interface in an axial piston machine that comprises a plurality of piston assemblies that are each adapted to receive a reciprocating drive force and configured, in response thereto, to cyclically move between an intake direction and a discharge direction, wherein each piston assembly comprises (1) a piston that includes a first end and a substantially rounded second end, the substantially rounded second end having a plurality of pockets formed in at least a portion of an outer surface thereof, and (2) an associated piston shoe including a cam engagement surface and a skirt portion, the skirt portion having an inner surface that defines a cavity within which the substantially rounded second end is inserted, the skirt portion engaging the substantially rounded second end to define the piston-to-shoe interface between the inner surface of the skirt portion and the outer surface of the substantially rounded second end, the method comprising the steps of: supplying the reciprocating drive force to each of the plurality of pistons to cause each piston to cyclically move between the intake direction and the discharge direction, whereby liquid is supplied from a liquid source to each piston-to-shoe interface to form a hydrostatic bearing at each piston-to-shoe interface; and while supplying the reciprocating drive force to each of the plurality of pistons, simultaneously: