| 摘要 |
The invention provides a hydromechanical system for limiting differential speed between first and second rotating members of a vehicle drivetrain subassembly. The hydromechanical system comprises a casing disposed within a housing of the subassembly which is rotatably coupled to the first rotating member of the drivetrain subassembly. Hydraulic fluid is supplied from a sump within the drivetrain subassembly housing to a reversible hydraulic pump disposed within the casing, wherein the reversible hydraulic pump pumps hydraulic fluid in response to relative rotation between the first and second rotating members. A piston assembly is disposed within the casing which includes a guide member, an actuating member and a chamber disposed therebetween, wherein the chamber receives the pumped hydraulic fluid. The system further includes a clutch having first and second sets of plates which are rotatably coupled to the first and second rotating members, respectively, wherein individual plates of the first and second sets are disposed in axially alternating relationship with one another. At least one restricted vent passage extends through the actuating member of the piston for venting the hydraulic fluid from the piston chamber to the housing sump when the pressure of the hydraulic flow is below a predetermined pressure. A spring element resiliently separates the actuating member and the clutch until the pressure of the hydraulic fluid reaches the predetermined pressure whereby the actuating member is urged against the clutch which closes the vent passage causing the actuating member to compress the clutch so as to rotatably couple the first and second rotating members of the drivetrain subassembly to one another.
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