Abstract: A hydraulic motor (10) comprising a front housing (12) which includes a first port (14) and a second port (16), a drive assembly (18), a drive link (22), and a shaft (24). The front housing (12) and the drive assembly (18) form a central bore (26) in which the drive link (22) and the shaft (24) are rotatably mounted. The drive assembly (18) comprises a spool valve (48) rotatably positioned within the central bore (26) and coupled to the shaft (24) by a key (140). Sealing rings (104) having a rotationally incompatible geometry (e.g., waved shapes) are used to seal interface surfaces of the rotor (54) and a high pressure seal assembly (156) is used to seal the front of a fluid chamber (154).

Abstract: A hydraulic motor (10) comprising a front housing (12) which includes a first port (14) and a second port (16), a drive assembly (18), a drive link (22), and a shaft (24). The front housing (12) and the drive assembly (18) form a central bore (26) in which the drive link (22) and the shaft (24) are rotatably mounted. The drive assembly (18) comprises a spool valve (48) rotatably positioned within the central bore (26) and coupled to the shaft (24) by a key (140). Sealing rings (104) having a rotationally incompatible geometry (e.g., waved shapes) are used to seal interface surfaces of the rotor (54) and a high pressure seal assembly (156) is used to seal the front of a fluid chamber (154).

Abstract: A hydraulic device includes a housing enclosing a hydraulic motor having a wobble shaft driven by a rotor of a gerotor gear set. An outer end of the wobble shaft is connected to the inner end portion of an output shaft. The output shaft extends axially through the housing and outward from the end of the housing opposite from the motor. A brake assembly holds the motor output shaft against rotation when the hydraulic motor is not operated. The brake assembly includes a series of compression springs provided toward the motor end of the housing, brake disks provided toward the end of the housing opposite from the motor, and an annular piston disposed axially between the springs and the brake disks. The piston and housing include corresponding radial stop surfaces that engage across a major portion of the stop surfaces to prevent over-compression of the springs and the piston from cocking when the piston engages the housing.