| 摘要 |
<p>PURPOSE:To improve actuation efficiency, by forming a movable valve body of a valve gear for feeding or discharging a pressure fluid, into being columniform while fitting the tip end in a convavity formed in a power piston via a sealing member. CONSTITUTION:A stepped hole 94 is formed in the rear of a first piston 19 in an axial direction, while a movable valve body 97 is slidably inserted in position over a medium diametral hole part 95 and a large diametral hole part 96 of the stepped hole 95. The movable valve body 97 is formed into being columniform, and its front end is fitted in the medium diametral hole part 95 via a seal ring 99. With the movable valve body 97 formed into being columniform, an area of the front end of the movable valve body 97 is able to be almost equal to a seating area on an inner flange part 104a of a sleeve 104 at an annular projection part 97a of the valve body 97. Accordingly, such force that the annular projection part 97a presses the inner flange part 104 becomes smaller so that force to open a feed valve is constituted to be small, thus braking operation comes speedy.</p> |
