| 摘要 |
PROBLEM TO BE SOLVED: To secure good responsiveness even when a hydraulic pump is used in common or when a pedal is suddenly actuated. SOLUTION: A spool 600 cooperates with a servo piston 400, a drain port opening/closing valve is arranged in the first land 610 part, a supply valve is arranged in the second land 620 part, and a throttle valve is arranged in the third land 630 part. In a communication path 1300 between a drain port and a servo chamber 480, between which a drain port opening/closing valve is arranged, the second communication path 2300 connecting the drain port, and the servo chamber 480 together is additionally arranged in parallel, and in the second communication path 2300, a check valve 800, which allows flow directing from the drain port side to the servo chamber 480 and forbids the reverse flow, is arranged. When a pedal is quickly actuated, a flow delay is generated in pressure fluid flowing into the servo chamber 480 from a hydraulic pump 30, and if increase of the pressure cannot comply with the volume increase of the servo chamber, the check valve 800 is opened so as to additionally supply fluid from the drain port side to the servo chamber 480. |
