Reversible variable displacement hydraulic pump and motor

A hydraulic vane pump/motor comprising:

• a housing assembly aligned along the central axis defining an internal cavity having a pair of spaced apart side walls perpendicular to the central axis and outer wall having a radial distance from the central axis which varies circumferentially in at least two spaced apart segments of the internal cavity, the internal cavity in the region of each of the at least two spaced apart segments having a circumferentially varying radius being provided with a fluid port formed in the housing;
• a generally cylindrically shaped rotor sized to fit within the internal cavity in the housing for rotation about the central axis, a rotor having an integral output shaft which extends axially through one of the walls in the housing assembly and a plurality of axially extending slots spaced about the cylindrical periphery of the rotor, each of the axially extending peripheral slots having a relatively deep independent localized blind pocket centrally formed therein, the blind pockets extending generally inwardly toward but terminating short of the central axis at a point which is inboard of the outer shaft periphery in axial end view;
• and
• a plurality of vanes oriented within each of the slots, each vane having a generally T-shaped body sized to fit within the slot, the body having a head portion and a leg portion depending therefrom, the head portion having an axial length generally corresponding to the axial length of the rotor and a radial length which is greater than the maximum travel of the vane, the leg portion extending into the central pocket in the rotor slot, the leg portion and the central pocket in the slot having an axial length which is substantially less than the axial length of the rotor, thereby providing improved resistance to vane side loading while maximizing rotor strength at smaller rotor diameters.