| 摘要 |
PURPOSE:To make the valve opening pressure of a relief valve constant all the time, by reducing the energizing force of a spring acting on a tappet of the relief valve, which makes pressure oil out of a pump flow back to a master cylinder in proportion as pressure in the master cylinder grows larger. CONSTITUTION:When a brake fluid beyond the preset quantity is stored in a reservoir 38 due to leakage or the like in a solenoid selector valve 24, a piston 140 goes down, making a valve spool 150 operate, and a relief passage 64 and a storage chamber 144 both are intercepted. Therefore, pressure in a relief passage 66 goes up with discharge oil out of a pump 56 to be driven in time of antiskid control, opening a relief valve 62, and the discharge oil out of the pump 56 is made to flow back to a master cylinder 10. At this time, pressure in the master cylinder 10 acts on a tappet 192 but this master cylinder pressure also acts on a piston 194 of the valve 62 and thereby energizing force of a spring 200 is weakened so that even if this master cylinder pressure is high enough, the valve opening pressure of the valve 62 never goes up. |
