US 5,967,285 A · Multi-function control valve for hydraulic coupling

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. A control valve assembly is located in the third flow path and provides a flow control function for regulating the fluid pressure in the piston chamber and supplying fluid to the clutch chamber for cooling the clutch assembly. The control valve assembly also provides a pressure relief function for limiting the fluid pressure in the piston chamber to a predetermined maximum value, and a thermal unload feature for venting the piston chamber when the fluid temperature exceeds a predetermined maximum value.

Claims19

Dependent claims

A hydraulic coupling for use in a driveline apparatus having a casing containing hydraulic fluid to rotatively couple first and second rotary members, the hydraulic coupling comprising:

a transfer clutch operatively connected between the first and second rotary members;
a piston housing defining a piston chamber;
a piston disposed in said piston chamber and actuatable to engage said transfer clutch and rotatively couple the first and second rotary members;
a hydraulic pump for providing a pumping action in response to relative rotation between the first and second rotary members;
a first flow path for supplying hydraulic fluid from a sump in the casing to said hydraulic pump;
a second flow path for supplying hydraulic fluid from said hydraulic pump to said piston chamber;
a third flow path for supplying hydraulic fluid from said piston chamber to a flow control chamber;
and
a control valve assembly located in said flow control chamber and defining a valve chamber which is in fluid communication with said flow control chamber, said control valve assembly having a flow control valve for regulating flow of hydraulic fluid into said valve chamber to control the pressure in said piston chamber for actuating said piston, a pressure relief valve for venting fluid from said flow control chamber into said valve chamber when the fluid pressure in said piston chamber exceeds a predetermined maximum pressure value, and a thermal unload valve for venting fluid from said flow control chamber into said valve chamber when the fluid temperature exceeds a predetermined maximum temperature value.

6 more elements

A hydraulic coupling comprising:

a first rotary member having a flow control chamber;
a second rotary member;
a drum housing fixed for rotation with said first rotary member;
a transfer clutch operatively coupled between said drum housing and said second rotary member;
a piston housing located in said drum housing and defining a transfer port, an outlet port, and a piston chamber in fluid communication with said transfer port and said outlet port;
a piston supported for movement in said piston chamber to actuate said transfer clutch for rotatively coupling said first and second rotary members;
a hydraulic pump operable to pump fluid to said piston chamber through said transfer port in response to speed differentiation between said first and second rotary members;
and
a control valve assembly installed in said flow control chamber and in fluid communication with said outlet port, said control valve assembly including a valve housing defining a valve chamber, a flow control valve for regulating fluid flow into said valve chamber to control the fluid pressure in said piston chamber, a pressure relief valve for venting fluid from said flow control chamber into said valve chamber when the fluid pressure in said piston chamber exceeds a predetermined maximum pressure value, and a thermal unload valve for venting fluid from said flow control chamber into said valve chamber when the fluid temperature in said piston chamber exceeds a predetermined maximum value.

6 more elements

Dependencies are inferred from the claim text.

Multi-function control valve for hydraulic coupling

Life of this patent

Multi-function control valve for hydraulic coupling

Life of this patent

Abstract

Claims19