| 摘要 |
PROBLEM TO BE SOLVED: To provide a vehicular hydraulic master cylinder which can, while suppressing cost, quickly replenish a hydraulic chamber with a sufficient hydraulic fluid during the operation of a hydraulic control device.SOLUTION: A relief port 4 and a supply port 5 are formed in a cylinder hole 2b, and cup seals 6, 7 are fitted to a piston 3. A bottomed cylindrical part 3a opening to a bottom part side of the cylinder hole is formed in the piston 3. A fluid passing hole 9 communicating the cylinder hole 2b with the bottomed cylindrical part 3a is formed on the cylinder hole opening side from the bottom cylindrical part 3a. The bottom cylindrical part 3a is provided with a closing member 10 which closes an opening of the fluid passing hole 9 when a hydraulic chamber 8 is under positive pressure, and opens the opening of the fluid passing hole 9 when the hydraulic chamber 8 is under negative pressure.SELECTED DRAWING: Figure 1 |
