Patent ID: 8257069

Claim:
A rotary abutment type hydraulic motor comprising: a housing formed of a housing top and housing bottom that serves to contain the fluid and moving parts of the motor; an annular fluid passage formed within said housing, said fluid passage located surrounding the outer circumference of a drive rotor; a first port and a second port formed by said housing and in fluid communications with said annular fluid passage; a rotor rotatably mounted within said fluid passage and having a pair of aligned rotor vanes, a first rotor vane radially extended outward from said rotor and symmetric to a second rotor vane; a face seal between said rotor and said housing, said face seal adapted such that high pressure inside the fluid passage creates an urging force between the rotor and the housing to force the face seal against the rotor, thereby increasing the sealing pressure against the joint face seal and the rotor; and at least one rotary abutment star that rotates in an overlapping concentric fashion over the path of each rotor vane and rotatably timed synchronizedly with said rotor such that between said rotor vane and said rotary abutment star, said rotor rotates in a pressure sealed manner, wherein said rotary abutment star comprises three symmetrical vanes, said rotary abutment star rotatably mounted to the housing and seal fluid cavities to separate high pressure from low pressure; wherein said first rotor vane and said second rotor vane form the main operative valve for said motor.