Hydraulic coupling for vehicle drivetrain

A hydraulic coupling for use with a vehicle drivetrain within a housing thereof containing hydraulic fluid to rotatively couple a pair of rotary members about a rotational axis, the hydraulic coupling comprising:

• a casing of a hollow construction that is rotatable within the housing about the rotational axis;
• a planetary gear set that connects the casing with one of the rotary members;
• a hydraulic pump located within the casing along the rotational axis and including a pumping component rotatively connected to the other rotary member to provide a pumping action upon relative rotation between the two rotary members;
• an inlet port through which hydraulic fluid is pumped into the casing by the hydraulic pump;
• a clutch including a piston chamber located within the casing and having an actuating piston that is received within the piston chamber and actuatable to engage the clutch and couple the two rotary members to each other;
• the casing including a transfer port through which the pumped hydraulic fluid is fed from the hydraulic pump to the piston chamber;
• an outlet port through which pumped hydraulic fluid flows from the piston chamber;
• and a control valve including a bimetallic valve element movable in a temperature compensated manner between an open position spaced from the outlet port and a closed position that closes the outlet port when the pumped fluid reaches a predetermined pressure to actuate the piston and engage the clutch to thereby rotatively couple the pair of rotary members to each other through the planetary gear set upon differential rotation of the rotary members.

A hydraulic coupling for use with a vehicle drivetrain within a housing thereof containing hydraulic fluid to rotatively couple a pair of rotary members about a rotational axis, the hydraulic coupling comprising:

• a casing of a hollow construction that is rotatable within the housing about the rotational axis and connected to one of the rotary members;
• a hydraulic pump located within the casing along the rotational axis and including an impeller rotatively connected to the other rotary member and having external teeth;
• the hydraulic pump also including an internal ring gear mounted by the casing for rotation eccentrically with respect to the toothed impeller and including internal teeth of a number one more than the impeller teeth and in a meshing relationship therewith to provide a pumping action upon relative rotation between the casing and the toothed impeller;
• an inlet port through which hydraulic fluid is pumped into the casing by the hydraulic pump;
• a clutch including a piston chamber located within the casing and having an actuating piston that is received within the piston chamber and actuatable to engage the clutch and couple the two rotary members to each other;
• the casing including a transfer port through which the pumped hydraulic fluid is fed from the hydraulic pump to the piston chamber;
• an outlet port through which pumped hydraulic fluid flows from the piston chamber;
• and a control valve including a bimetallic valve element movable in a temperature compensated manner between an open position spaced from the outlet port and a closed position that closes the outlet port when the pumped fluid reaches a predetermined pressure to actuate the piston and engage the clutch to thereby rotatively couple the pair of rotary members to each other upon differential rotation of the rotary members.

A hydraulic coupling for use with a vehicle drivetrain within a housing thereof containing hydraulic fluid to rotatively couple a pair of rotary members about a rotational axis, the hydraulic coupling comprising:

• a casing of a hollow construction that is rotatable within the housing about the rotational axis;
• a planetary gear set that connects the casing with one of the rotary members;
• a hydraulic pump located within the casing along the rotational axis and including an impeller rotatively connected to the other rotary member and having external teeth;
• the hydraulic pump also including an internal ring gear mounted by the casing for rotation eccentrically with respect to the toothed impeller and including internal teeth of a number one more than the impeller teeth and in a meshing relationship therewith to provide a pumping action upon relative rotation between the casing and the toothed impeller;
• an inlet port through which hydraulic fluid is pumped into the casing by the hydraulic pump;
• a clutch including a piston chamber located within the casing and having an actuating piston that is received within the piston chamber and actuatable to engage the clutch and couple the two rotary members to each other;
• the casing including a transfer port through which the pumped hydraulic fluid is fed from the hydraulic pump to the piston chamber;
• an outlet port through which pumped hydraulic fluid flows from the piston chamber;
• and a control valve including a bimetallic valve element movable in a temperature compensated manner between an open position spaced from the outlet port and a closed position that closes the outlet port when the pumped fluid reaches a predetermined pressure to actuate the piston and engage the clutch to thereby rotatively couple the pair of rotary members to each other upon differential rotation of the rotary members.

A hydraulic coupling for use with a vehicle drivetrain within a housing thereof containing hydraulic fluid to rotatively couple a pair of rotary members about a rotational axis, the hydraulic coupling comprising:

• a casing of a hollow construction that is rotatable within the housing about the rotational axis;
• a planetary gear set that connects the casing with one of the rotary members;
• a hydraulic pump located within the casing along the rotational axis and including an impeller rotatively connected to the other rotary member and having external teeth;
• the hydraulic pump also including an internal ring gear mounted by the casing for rotation eccentrically with respect to the toothed impeller and including internal teeth of a number one more than the impeller teeth and in a meshing relationship therewith to provide a pumping action upon relative rotation between the casing and the toothed impeller;
• an inlet port through which hydraulic fluid is pumped into the casing by the hydraulic pump;
• a clutch including a piston chamber located within the casing and having an actuating piston that is received within the piston chamber and actuatable to engage the clutch and couple the two rotary members to each other;
• the casing including a transfer port through which the pumped hydraulic fluid is fed from the hydraulic pump to the piston chamber;
• an outlet port through which pumped hydraulic fluid flows from the piston chamber;
• the outlet port including a main passage and a bleed passage;
• and a control valve including a bimetallic valve element movable in a temperature compensated manner between an open position spaced from the outlet port and a closed position that closes the main passage of the outlet port when the pumped fluid reaches a predetermined pressure to actuate the piston and engage the clutch to thereby rotatively couple the pair of rotary members to each other upon differential rotation of the rotary members with temperature compensation provided by the bimetallic valve element of the control valve and with the bleed passage allowing hydraulic fluid to flow from the piston chamber.

A hydraulic coupling for use with a vehicle drivetrain within a housing thereof containing hydraulic fluid to rotatively couple a pair of rotary members about a rotational axis, the hydraulic coupling comprising:

• a casing of a hollow construction that is rotatable within the housing about the rotational axis;
• a planetary gear set that connects the casing with one of the rotary members;
• a hydraulic pump located within the casing along the rotational axis and including a pumping component rotatively connected to the other rotary member to provide a pumping action upon relative rotation between the two rotary members;
• an inlet port through which hydraulic fluid is pumped into the casing by the hydraulic pump;
• a clutch including a piston chamber located within the casing and having an actuating piston that is received within the piston chamber and actuatable to engage the clutch and couple the two rotary members to each other;
• the casing including a transfer port through which the pumped hydraulic fluid is fed from the hydraulic pump to the piston chamber;
• the piston including an outlet port through which pumped hydraulic fluid flows from the piston chamber;
• and a control valve mounted on the piston and including a bimetallic valve element movable in a temperature compensated manner between an open position spaced from the outlet port and a closed position that closes the outlet port when the pumped fluid reaches a predetermined pressure to actuate the piston and engage the clutch to thereby rotatively couple the pair of rotary members to each other through the planetary gear set upon differential rotation of the rotary members.

A hydraulic coupling for use with a vehicle drivetrain within a housing thereof containing hydraulic fluid to rotatively couple a pair of rotary members about a rotational axis, the hydraulic coupling comprising:

• a casing of a hollow construction that is rotatable within the housing about the rotational axis;
• a planetary gear set that connects the casing with one of the rotary members;
• a hydraulic pump located within the casing along the rotational axis and including a pumping component rotatively connected to the other rotary member to provide a pumping action upon relative rotation between the two rotary members;
• an inlet port through which hydraulic fluid is pumped into the casing by the hydraulic pump;
• a clutch including a piston chamber located within the casing and having an actuating piston that is received within the piston chamber and actuatable to engage the clutch and couple the two rotary members to each other;
• the casing including a transfer port through which the pumped hydraulic fluid is fed from the hydraulic pump to the piston chamber;
• an outlet port through which pumped hydraulic fluid flows from the piston chamber back to the pump;
• and a control valve including a bimetallic valve element movable in a temperature compensated manner between an open position spaced from the outlet port and a closed position that closes the outlet port when the pumped fluid reaches a predetermined pressure to actuate the piston and engage the clutch to thereby rotatively couple the pair of rotary members to each other through the planetary gear set upon differential rotation of the rotary members.

A hydraulic coupling for use with a vehicle drivetrain within a housing thereof containing hydraulic fluid to rotatively couple a pair of rotary members about a rotational axis, the hydraulic coupling comprising:

• a casing of a hollow construction that is rotatable within the housing about the rotational axis and connected to one of the rotary members;
• a hydraulic pump located within the casing along the rotational axis and including a pumping component rotatively connected to the other rotary member to provide a pumping action upon relative rotation between the two rotary members;
• an inlet port through which hydraulic fluid is pumped into the casing by the hydraulic pump;
• a clutch including a piston chamber located within the casing and having an actuating piston that is received within the piston chamber and actuatable to engage the clutch and couple the two rotary members to each other;
• the casing including a transfer port through which the pumped hydraulic fluid is fed from the hydraulic pump to the piston chamber;
• the actuating piston including an outlet port through which pumped hydraulic fluid flows from the piston chamber;
• and a control valve mounted on the actuating piston and including a valve element movable between an open position spaced from the outlet port and a closed position that closes the outlet port when the pumped fluid reaches a predetermined pressure to actuate the piston and engage the clutch to thereby rotatively couple the pair of rotary members to each other upon differential rotation of the rotary members.