Radial piston machine

Claim 1

A radial piston machine for transmitting fluid therethrough, said machine comprising a stator, a rotor disposed in said stator and rotatable on a stationary control pintle having supply and discharge channels, a radial through-bore in said rotor adapted for periodic connection to said supply and discharge channels, said through-bore containing a first and a second radially displaceable spherical piston disposed at opposite ends of the bore on opposed sides of the control pintle, each piston including a radially outwardly disposed ball seated in a radially inwardly disposed unitary cylindrical sleeve, with each piston radially slidable relative to a cam surface on said stator, each said sleeve comprising a cylindrical outer wall of uniform diameter and circumference each sleeve including an axially concentric through passage having a conic seat for its associated ball at one end to provide a line contact therewith, and in which said passage bounds an outwardly tapering wall of said sleeve at the other end of said sleeve forming a peripheral integral sleeve lip positioned to sealingly engage the adjacent bore wall with a gap sealing lip responsive to pressure above a predetermined level passing through said passage.