Patent ID: 6578692
Filing Date: 2003-06-17
Classification: F16D,F16H,Y10T

Abstract:
A drive axle assembly for transferring drive torque from a vehicle drivetrain to a pair of axleshafts, comprising:a drive case driven by the drivetrain; first and second output shafts rotatably supported by said drive case and adapted for connection to the axleshafts; a first hydraulic coupling operably installed between said drive case and said first output shaft and including a multi-plate friction clutch, a fluid pump operable to pump fluid from a sump to a pressure chamber in response to speed differentiation between said drive case and said first output shaft, a piston retained in said pressure chamber to exert a clutch engagement force on said friction clutch proportional to the fluid pressure in said pressure chamber, and a control valve mounted to said piston, said control valve having a valve member moveable from a closed position to an open position when the fluid pressure in said pressure chamber exceeds a predetermined maximum pressure value for venting fluid to said sump, and a thermal actuator operable for moving said valve member from its closed position to its open position when the temperature of the fluid in said sump exceeds a predetermined maximum temperature level; and a second hydraulic coupling operably installed between said drive case and said second output shaft and including a multi-plate friction clutch, a fluid pump operable to pump fluid from said sump to a pressure chamber in response to speed differentiation between said drive case and said second output shaft, a piston retained in said pressure chamber to exert a clutch engagement force on said friction clutch in proportion to the fluid pressure in said pressure chamber, and a control valve mounted to said piston, said control valve having a valve member moveable from a closed position to an open position when the fluid pressure in said pressure chamber exceeds a predetermined maximum pressure value for venting fluid to said sump, and a thermal actuator operable for moving said valve member from its closed position to its open position when the temperature of the fluid in said sump exceeds a predetermined maximum temperature value.