| 摘要 |
<p>PURPOSE:To temporarily release a parking brake by utilizing the hydraulic pressure of an existing pressure source. CONSTITUTION:While a vehicle is running, the hydraulic pressure from a pump 21 is supplied to an oil chamber 17 from a parking brake valve 23. A piston 10 is moved in a non-brake direction resisting against a spring 11, and a parking brake is not operated. When an engine stops, hydraulic pressure is not supplied from the pump 21, as a result, the piston 10 moves in a brake direction, resulting in the operation of the parking brake. An orbit roll and a releasing chamber are communicated with each other through a switching valve 62 by operating an operation lever 65. The steering wheel 31 is turned to send pressure oil from an orbit roll 32 to the releasing chamber 60. The piston 10 moves in a non-bake direction resisting against the spring 11 resulting in the release of the parking brake.</p> |
