Closed position maintainable selector valve, knee torque device using the valve, and artificial leg

摘要

A selector valve capable of maintaining a closed position for a while even if an operating force to a valve element ( 80 ) is eliminated when the selector valve ( 10 ) is switched from a closed position (braking state) to an open position. The valve element ( 80 ) of the selector valve ( 10 ) receives an operating force from the outside and a returning force in the opposite direction of the operating force by a valve spring ( 90 ). Accordingly, the valve element ( 80 ) opens and closes the valve by making the first end ( 801 ) of the valve element ( 80 ) seat on/unseat from a valve seat ( 48 ) on the housing ( 20 ) side according to the presence or absence of the operating force. A first port ( 31 ) and a second port ( 32 ) on both sides of the valve seat ( 48 ) are connected or cut off from each other by the opening and closing. The valve element ( 80 ) is formed in a stepped structure, and receives a force based on a difference in pressure receiving area by the stepped structure which results from the pressure of hydraulic fluid. The force can maintain the closed position of the valve for a while.