Abstract: A rotary fluid pressure device (11) having a housing (13,31), inlet and outlet ports (21,23), a gerotor gear set (15), a valve member (51) and an input-output shaft (49). A seal assembly (73) is disposed radially between the shaft (49) and the housing (31). The seal assembly comprises, in the order of leakage flow from a case drain region (63), a high pressure shaft seal (77), an annular chamber (71) in which is disposed a rigid back-up member (79;91) for the seal (77), a drain passage (81) communicating from the annular chamber (71) to a case drain port (47), and a low pressure shaft seal (83). The back-up member (79;91) may cooperate with either the housing (31) or the seal (77) or the input-output shaft (49) to define a fluid passage (87,89;93,95), so that any leakage flow past the high pressure shaft seal (77) flows through the drain.

Abstract: A rotary fluid pressure device (11) having a housing (13,31), inlet and outlet ports (21,23), a gerotor gear set (15), a valve member (51) and an input-output shaft (49). A seal assembly (73) is disposed radially between the shaft (49) and the housing (31). The seal assembly comprises, in the order of leakage flow from a case drain region (63), a high pressure shaft seal (77), an annular chamber (71) in which is disposed a rigid back-up member (79;91) for the seal (77), a drain passage (81) communicating from the annular chamber (71) to a case drain port (47), and a low pressure shaft seal (83). The back-up member (79;91) may cooperate with either the housing (31) or the seal (77) or the input-output shaft (49) to define fluid passage means (87,89;93,95), so that any leakage flow past the high pressure shaft seal (77) flows through the drain passage (81) to the case drain port (47).

Abstract: A gerotor motor including a brake package, and a method for setting the load holding torque of the brake package. The endcap assembly (21) defines a set of internal threads (85) disposed adjacent a brake package piston member (75). An enclosure member (87) defines a spring seat (115) for a set of Belleville washers (105), and defines a set of external threads (88) engaging the internal threads (85). Upon assembly of the motor and brake package, a resistance load is applied to a motor output shaft (43) corresponding to a desired load holding torque. The motor is pressurized sufficiently to rotate the output shaft in opposition to the resistance load. The enclosure member (87) is rotated so that it moves axially in a direction to increase the bias preload on the Belleville washers (105) until the output shaft (43) no longer rotates.

Abstract: A rotary fluid pressure device (11) having a housing (13,31), inlet and outlet ports (21,23), a gerotor gear set (15), a valve member (51) and an input-output shaft (49). A seal assembly (73) is disposed radially between the shaft (49) and the housing (31). The seal assembly comprises, in the order of leakage flow from a case drain region (63), a high pressure shaft seal (77), an annular chamber (71) in which is disposed a rigid back-up member (79) for the seal (77), a drain passage (81) communicating from the annular chamber (71) to a case drain port (47), and a low pressure shaft seal (83). The back-up member (79) may cooperate with either the housing (31) or the seal (77) to define radial fluid passage means (87,89), so that any leakage flow past the high pressure shaft seal (77) flow to the case drain port (47).

Abstract: A two-speed gerotor motor of the type having a stationary valve member (19) defining a plurality of stationary valve passages, each including an upstream passage portion for commutating fluid communication with a moveable valve member (43), and a downstream passage portion in continuous fluid communication with a volume chamber (33) of the gerotor gear set. In some of the stationary valve passages (113), the upstream (115) and downstream (117) passage portions are blocked from direct fluid communication. A control valve spool (89) has a first position (FIG. 8) permitting unrestricted fluid communication between the upstream and downstream passage portions, for normal low-speed operation. The control valve spool has a second position (FIG.