Abstract: A control valve (80) of a hydraulic coupling (32) controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control coupling between two rotary members such as by operation of a clutch (68). The casing (34) is connected to one of the rotary members while a pumping component embodied by an impeller (50) is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes an elongated valve element (82) mounted within a recess (98) to provide accurate control of its closure when the pumped hydraulic fluid reaches a predetermined pressure corresponding to a predetermined extent of relative rotation between the two drivetrain members.

Abstract: A hydraulic coupling (38) for coupling a casing (46) and a pair of axle half shafts (40) of an auxiliary drive axle (36) of a vehicle drivetrain (22) includes a housing (44) for containing hydraulic fluid and the casing (44) rotatively mounted within the housing. A clutch (76) extends between the casing (46) and each of the axle half shafts (40) and is actuable to transfer torque therebetween by the operation of a pair of hydraulic pumps (90) that provide pumped hydraulic fluid to a pair of piston chambers (110) whose pistons (120) actuate the clutch. An outlet port (122) of each piston chamber (110) and an associated temperature compensated valve (124) and a pressure relief valve (126) of each piston chamber control the clutch actuation.

Abstract: A vehicle drivetrain differential (22) driven by a rotary drive member (24) rotatively drives a pair of rotary members (26, 28) and includes a housing (30) for containing hydraulic fluid and in which a hydraulic coupling (32) is received. A casing (34) of the hydraulic coupling has a ring gear (44) rotatively driven by the rotary drive member (24). A planetary gear set (36) of the bevel gear type is located within the casing (34) and includes a pair of bevel gears (124, 126) having associated spline connections (128, 130) to the pair of rotary members (26, 28), and the planetary gear set also includes planet gears 132 that revolve with the casing 34 and are meshed with both bevel gears to provide a differential gear action. A fluid inlet 58 and an outlet port 78 of the casing are provided with a gerotor type pump (48) provides pumping of hydraulic fluid into and out of the casing.

Abstract: A control valve (80) of a hydraulic coupling (32) controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control coupling between two rotary members such as by operation of a clutch (68). The casing (34) is connected to one of the rotary members while a pumping component embodied by an impeller (50) is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes an elongated valve element (82) mounted within a recess (98) to provide accurate control of its closure when the pumped hydraulic fluid reaches a predetermined pressure corresponding to a predetermined extent of relative rotation between the two drivetrain members.

Abstract: A supplemental pressurized hydraulic supply (103) provides control of a hydraulic coupling (32a,32b,32c) that normally operates in response to differential rotation between a pair of rotary members (26,28) to provide actuation of a clutch (68) that couples the pair of rotary members. A rotary seal assembly (104) of the supply (103) feeds pressurized hydraulic fluid to the coupling to provide supplemental actuation of the clutch (68) that is normally actuated by hydraulic fluid from a hydraulic pump (48) that operates in response to the differential rotation between the pair of rotary members. In one embodiment, the hydraulic coupling (32a) also includes a differential gear set (36). A further embodiment of the hydraulic coupling (32b) includes a clutch (68) having a pair of clutch packs (69) that can be individually actuated by the supplement pressurized hydraulic fluid supply (103).

Abstract: A control valve (80) of a hydraulic coupling (32) controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control coupling between two rotary members such as by operation of a clutch (68). The casing (34) is connected to one of the rotary members while a pumping component embodied by an impeller (50) is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes an elongated valve element (82) mounted within a recess (98) to provide accurate control of its closure when the pumped hydraulic fluid reaches a predetermined pressure corresponding to a predetermined extent of relative rotation between the two drivetrain members.

Abstract: A control valve (80) of a hydraulic coupling (32) controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control coupling between two rotary members such as by operation of a clutch (68). The casing (34) is connected to one of the rotary members while a pumping component embodied by an impeller (50) is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes an elongated valve element (82) mounted within a recess (98) to provide accurate control of its closure when the pumped hydraulic fluid reaches a predetermined pressure corresponding to a predetermined extent of relative rotation between the two drivetrain members.

Abstract: A hydraulic coupling (32) includes a control valve (80) that controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control operation of a clutch (68) for coupling between two rotary members. The casing (34) is connected to one of the rotary members while a pumping component embodied by an impeller (50) is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes a by metallic valve element (82) mounted within a recess (98) to provide accurate temperature compensated control of its closure when the pumped hydraulic fluid reaches a predetermined pressure corresponding to a predetermined extent of relative rotation between the two drivetrain members.

Abstract: A hydraulic coupling (32) includes a control valve (80) that controls pumping from a casing inlet port (58) by a hydraulic pump (48) through a casing outlet port (78) to control coupling between two rotary members. The casing (34) is connected to one of the rotary members while an impeller (50) having between five and seven external teeth is connected to the other rotary member and meshed with an internal ring gear (54) having one more tooth than the number of impeller teeth to provide sufficient pumping capacity so that the pump can act as a brake while still having relatively constant pumping pressure. The control valve (80) includes a bimetallic valve element (82) that compensates for temperature changes and may also include a speed sensitive valve closure (104) for providing immediate coupling without delay above certain speeds of operation. Mounting of the bimetallic valve element (82) of control valve (80) within a recess (98) provides accurate control of the temperature compensation.