Abstract: A rotary radial piston pump or motor has a cylinder barrel rotating on a fixed pintle with a fluid exit at the fixed end of the pintle and an inlet at the opposite free end. A fluid impeller boosts the pressure entering the inlet and a filter prevents dirt entering. When applied to a hydrostatic transmission with pump and motor on a common pintle a pair of opposed non-return valves admit make-up fluid at one end of the pintle and a pressure relief valve provides overload relief at the other end of the pintle.
Type:
Grant
Filed:
May 21, 1986
Date of Patent:
August 18, 1987
Assignee:
Unipat AG
Inventors:
Christian H. Thoma, George D. M. Arnold
Abstract: A hydraulic radial piston pump or motor comprises a rotary cylinder unit (20) mounted to rotate on a fixed pintle (25), the unit (20) having radial cylinder bores formed by cylinder sleeves (23) each housing a piston (40) connected by a ball joint (44) to a slipper (45) engaging a surrounding annular track ring (47). The unit (20) also includes a separately formed central sleeve (21) having ports (26) cooperating with ports (31,32) in the pintle, the pintle ports (31,32) and the sleeve ports (26) being elongated in a circumferential direction. The pintle has three parallel flow passages, two (28') of smaller diameter than the third (27'). The slippers (45) are held resiliently against the track ring (47) by a band (66) having windows (68) which fit the slippers, the band being of resilient material and split at one point. The cylinder unit (20) has a rounded external surface and is free to float in an axial direction which provides a self-centering effect.
Type:
Grant
Filed:
September 6, 1983
Date of Patent:
January 13, 1987
Assignee:
Unipat AG
Inventors:
Christian H. Thoma, George D. M. Arnold