| 摘要 |
PURPOSE:To enable free alteration of control properties of a relief pressure in relation to an applied current, by a method wherein a spool, sucked in response to a control current, is supported at both ends thereof by means of a spring for setting a relief pressure and a spring for balancing. CONSTITUTION:A spool 13 is balanced by a spring 19 for setting a relief pressure and a spring 27 for balancing, and the forward end of the spool is positioned in a place facing the lower end of a yoke 22. When a current is applied to a solenoid 29 under this condition, an upward suction force, corresponding to the applied current, is exerted on the spool 13. Thus, the spool 13, balanced between the two springs 19 and 27, loses its balance, and the spool is displaced upward according to a suction force, resulting in reduction of the counterforce of the spring 19 and a change in the set value of a relief pressure. |
