Abstract: A hydraulic coupling is disclosed for use in motor vehicle driveline applications to rotatively couple a pair of rotary members. The hydraulic coupling includes a multi-plate clutch assembly operatively connecting the two rotary members and an actuator assembly for actuating the clutch assembly in response to and as a function of speed differentiation between the two rotary members. The actuator assembly includes a hydraulic pump, a piston disposed in a piston chamber, and a fluid control system for controlling the fluid pressure supplied to the piston chamber by the hydraulic pump to control the clutch engagement force exerted by the piston on the clutch assembly. The fluid control system includes a pressure relief valve operable for limiting the fluid pressure in the piston chamber to a predetermined maximum pressure value.

Abstract: A differential assembly is disclosed having a pair of hydraulic couplings installed in a differential casing and operably arranged to rotatively couple first and second rotary members to the differential casing. Each hydraulic coupling includes a clutch pack operatively connected between one of the rotary members and the casing, a hydraulic pump, and a fluid distribution system for delivering pumped fluid to a pressure chamber to actuate a piston for engaging the clutch pack and to a clutch chamber to cool the clutch pack.

Abstract: A hydraulic coupling includes a clutch assembly operatively connecting two rotary members and an actuator assembly for actuating the clutch assembly in response to speed differentiation between the two rotary members. The clutch assembly includes a multi-plate clutch pack alternately connected between the two rotary members within a clutch chamber. The actuator assembly includes a hydraulic pump, a piston disposed in a piston chamber, and a fluid distribution system having a first flow path between a supply chamber and the hydraulic pump, a second flow path between the hydraulic pump and the piston chamber, and a third flow path between the hydraulic pump and the clutch chamber. The fluid delivered to the piston chamber controls engagement of the piston with the clutch pack for controlling actuation of the clutch assembly. Additionally, the fluid delivered to the clutch chamber is used to cool and lubricate the clutch pack.

Abstract: A hydraulic coupling including a multi-plate clutch assembly operably connecting two relatively rotatable members and an actuator assembly for actuating the clutch assembly in response to speed differentiation between the two rotary members. The actuator assembly includes a hydraulic pump, a piston disposed in a piston chamber, and a fluid distribution system including a first flow path for supplying hydraulic fluid from a sump to the hydraulic pump and a second flow path for supplying hydraulic fluid from the hydraulic pump to the piston chamber. Hydraulic pressure in the piston chamber controls the magnitude of the clutch engagement force exerted by the piston on the clutch assembly. The fluid distribution system further includes a third flow path between the piston chamber and a clutch chamber.

Abstract: A power transfer system including a variable speed electric motor and a single speed transmission is disclosed for transferring power from a source of power to a pair of driven wheels. This arrangement is particularly adapted for use in electric vehicles incorporating a high speed electric motor. In a preferred embodiment, the single speed transmission includes a housing, an input shaft for receiving drive torque from the electric motor, at least one output shaft and an intermediate shaft supported for rotation of the housing between the input shaft and the output shaft. The single speed transmission further includes a parking sprag arrangement for preventing rotation of the output shaft when a park mode is selected.

Abstract: The present invention is directed to an improved power transfer system for use in four-wheel drive vehicles having a transfer case equipped with a torque transfer arrangement that is operable for automatically controlling the drive torque delivered to the front and rear drivelines of the vehicle and establishing an on-demand four-wheel drive mode.

Abstract: A viscous coupling apparatus having enhanced torque progression characteristics. The viscous coupling apparatus includes two sets of viscous coupling plates which are interleaved and mounted with rotatable members for relative rotation therebetween. Each plate is a generally circular ring of thin plate material and has one or more openings formed therein. The openings include coined edge surfaces that form an inclined surface and an arcuate wiping surface. The coined edges facilitate the wiping and removal of viscous fluid from the surface of an adjacent coupling plate when relative rotation and frictional contact occurs between adjacent plates without generating excessive wear on one of the mating plates. The removal of the viscous fluid promotes enhanced frictional contact between the facing adjacent plate surfaces and results in an increased torque transmission characteristic.

Abstract: The present invention is directed to an improved "on-demand" power transfer system of the type having a transfer mechanism incorporated into the driveline of a four-wheel drive vehicle. The transfer mechanism is arranged to deliver drive torque to the driven wheels so as to establish a two-wheel drive mode of operation. In addition, the transfer mechanism is equipped with a clutch assembly for selectively delivering drive torque to the non-driven wheels for establishing a four-wheel drive mode of operation. The transfer mechanism is further equipped with a linear actuator mechanism for actuating the clutch assembly. The linear actuator mechanism is preferably mounted directly to the transfer mechanism to substantially minimize the packaging requirements associated with the on-demand power transfer system while concomitantly enhancing in-service reliability and allowing pre-assembly of the transfer mechanism prior to final installation into the vehicle driveline.

Abstract: A viscous coupling apparatus having enhanced torque progression characteristics. The viscous coupling apparatus includes two sets of viscous coupling plates which are interleaved and mounted with rotatable members for relative rotation therebetween. Each plate is a generally circular ring of thin plate material and has one or more openings formed therein. The openings include coined edge surfaces that form an inclined surface and a planar wiping surface. The coined edges facilitate the wiping and removal of viscous fluid from the surface of an adjacent coupling plate when relative rotation and frictional contact occurs between adjacent plates without generating excessive wear on one of the mating plates. The removal of the viscous fluid promotes enhanced frictional contact between the facing adjacent plate surfaces and results in an increased torque transmission characteristic.

Abstract: A viscous coupling apparatus having enhanced torque progression characteristics. The viscous coupling apparatus includes two sets of viscous coupling plates which are interleaved and mounted with rotatable members for relative rotation therebetween. Each plate is a generally circular ring of thin plate material and has one or more openings formed therein. The openings include coined edge surfaces that form an inclined surface and a planar wiping surface. The coined edges facilitate the wiping and removal of viscous fluid from the surface of an adjacent coupling plate when relative rotation and frictional contact occurs between adjacent plates without generating excessive wear on one of the mating plates. The removal of the viscous fluid promotes enhanced frictional contact between the facing adjacent plate surfaces and results in an increased torque transmission characteristic.

Abstract: A method of hardening and flattening a viscous coupling plate generally combining a heat treatment process followed by roller leveling is disclosed. The heat treatment process produces an epsilon iron nitride surface layer of the desired hardness on the plate. Subsequent to the heat treatment, the plates are passed through a series of leveling rolls to produce a sufficiently flat plate. The flat rolling process can incorporate a single pass or multiple passes through the leveling rolls. The method of the present invention eliminates any distortion in the plates and brings them within any required flatness specifications, as well as producing viscous coupling plates that exhibit improved resistance to permanent deformation under operating conditions.