| 摘要 |
PROBLEM TO BE SOLVED: To prevent the floor sticking of a master cylinder when a high pressure source fails in a hydraulic brake device provided with a spool displaced in response to the master cylinder pressure to connect one of the high pressure source and a low pressure source to a control hydraulic port. SOLUTION: This hydraulic brake device is provided with a master cylinder pressure chamber 60 connected to a master cylinder 12, a spool 58 displaced by the liquid pressure of the master cylinder pressure chamber 60, a circular groove 58a arranged on the spool 58 and opened to a low pressure source port 30 or a high pressure source port 40, a control hydraulic output port 46 opened to the circular groove 58a and connected to a wheel cylinder 52, and a low pressure source passage control valve 28 arranged in a low pressure source passage 2 connecting the low pressure source port 30 and a reservoir tank 22 and opened when a pump 34 fails. |
