| 摘要 |
A hydraulic brake apparatus is provided for increasing a braking force with a brake feeling similar to that during a normal brake operation, even if a brake pedal is operated during an automatic brake operation. A valve device having a spool is placed in a power piston and is transferred between first and second positions depending on the operation of the brake pedal. At the first position, a power chamber is at atmospheric pressure level, while at the second position a fluid communication is established between the power chamber and an auxiliary hydraulic pressure source. The spool is driven independent of the operation of the brake pedal. When a hydraulic pressure is applied to the spool, the valve device is switched to the second position, urging the power piston to advance, without transmitting the resultant force to the brake operation member. The driving device, when applied with no hydraulic pressure, retains the valve device at the first position.
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