| 摘要 |
<p>PROBLEM TO BE SOLVED: To surely discharge a residual pressure of an automatic brake action by shortening a lost stroke. SOLUTION: When an input is applied to a primary piston 3, at first a third return spring 45 is bent, and the primary piston 3, a first cylinder member 6, a secondary piston 4, and a second cylinder member 8 are integrally advanced. The advancement of the first and the second cylinder members 6 and 8 close first opening/closing valves 2b and 39b and second opening/closing valves 2c and 42 simultaneously and generate MCY pressure in hydraulic pressure chambers 10 and 11. This constitution can shorten the lost stroke of the primary piston 3 till generating the MCY pressure. When the residual pressure is generated in the respective hydraulic pressure chambers 10 and 11 by the automatic brake, the primary and secondary pistons 3 and 4 are retreated by the hydraulic pressure raised by the residual pressure so that a valve element 39b is separated from the rear end of the secondary piston 4 and a valve element 42 is separated from a valve seat 2c so that the residual pressures in the both hydraulic pressure chambers are discharged.</p> |
