VEHICLE DRIVELINE HAVING TORQUE TRANSFER DEVICE THAT IS OPERATED ON FLUID PRESSURE

摘要

A vehicle driveline having a torque transfer device and a fluid circuit for operating the torque transfer device. The fluid circuit has a motor, a pump driven by the motor, an actuator, and a pair of valves. The valves are arranged in the fluid circuit to control fluid circulation within the fluid circuit and can be operated such that fluid pressure in the actuator can be maintained (i.e., to maintain engagement of the torque transfer device) without operating the pump.

主权项

1. A vehicle driveline comprising:
a clutch having a plurality of first clutch plates and a plurality of second clutch plates that are interleaved with the first clutch plates; a reservoir configured to hold hydraulic fluid; a hydraulic ram coupled to the friction clutch, the hydraulic ram having a piston chamber and a piston that is movable in the piston chamber between a first position which is retracted relative to the first and second clutch plates, and a second position in which the piston is extended toward the first and second clutch plates to a greater extent than when the piston is in the first position; a first valve coupled for fluid communication with the piston chamber; a second valve coupled for fluid communication with the piston chamber, and the reservoir; and a pump configured to pump hydraulic fluid from the reservoir to the piston chamber via the first valve; wherein the first valve is operable in a first mode wherein fluid communication is permitted between the pump and the piston chamber, and a second mode wherein fluid communication between the pump and piston chamber is prevented; wherein the second valve is operable in a third mode wherein fluid communication is permitted between the piston chamber and the reservoir, and a fourth mode wherein fluid communication between the piston chamber and the reservoir is prevented; and wherein the second valve is configured to be in the third mode when a pressure within the piston chamber is less than a predetermined pressure, and the second valve is configured to be in the fourth mode when the pressure in the piston chamber is greater than the predetermined pressure.