To provide a hydraulic power transmission device having simple construction for suppressing overtorque at sudden starting or sudden braking and preventing interference with ABS at sudden braking.
The hydraulic power transmission device 10 comprises a torque limiter mechanism coaxially arranged outside a washer member 36 for thrusting a axially movable relief washer member 48 via a relief spring 55 against a rotor end face to close a drain communication passage and for moving the relief washer member 48 backward to open the drain communication passage 44 and thereby drain high pressure oil from a piston chamber 26 to a low pressure chamber when hydraulic force on the relief washer member 48 via the drain communication passage 44 exceeds predetermined spring load. A taper groove of a weight member 50 to be rotated integrally with a housing engages with a ball 52 of the relief washer member 48, and the relief washer member 48 is pushed down by the inertial force of the weight member 50 to open the drain communication passage 44 at stopping or starting the rotation of the housing 12.
HOSHINA TAIJI
SATO MAKOTO
