| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic booster capable of further effectively shortening the whole length. SOLUTION: The right end of the axial hole of a housing 4 for a hydraulic booster is blocked in a liquid-tight state with a plug (a blocking member) 5. A power piston 7 is constituted as a stepped piston, and a front side large diameter part 7a is slidably fitted in a liquid-tight state into the axial hole of the housing 4 for the hydraulic booster, while a small diameter part 7b of the power piston 7 is slidably fitted in a liquid-tight state into the axial hole of the plug 5. A radial hole 7b of the large diameter part 7a, and an annular groove 8b of an input shaft 8 constitute a supply valve 14 for supplying hydraulic pressure of a hydraulic pressure source to a power chamber 11. A radial hole 7e of the small diameter part 7b, and an annular groove 8d of the input shaft 8 constitute a exhaust valve 15 for discharging hydraulic pressure to a hydraulic pressure reservoir of the power chamber 11. These valves 14, 15 are composed of spool valves. Since the exhaust valve 15 is provided in a position corresponding to the rear end part of the plug 5, the housing 4 can be shortened. |
