| 摘要 |
PURPOSE:To achieve a constant lift regardless of the pressure fluctuation of the hydraulic oil supplied to a logic valve if the electric current flowing to the coil of an electromagnetic proportioning valve by employing the electromagnetic proportioning valve for controlling the lift of poppet of the logic valve etc. CONSTITUTION:The hydraulic oil in a supply port P is introduced through an oil passage 15 into a chamber 4b on one side of a spool 4 to push out the spool 4 to the left. The hydraulic oil in a supply port C is introduced into a chamber on the right-hand side of a plunger 2b via an oil passage 16, and then to a chamber 4c on the other side of the spool 4 via a throttle passage 17 to push out the spool to the right. A chamber 2d on the right-hand side of the plunger 2b and a left-hand side chamber 2e are communicated by an oil passage 18. When a coil 2a is applied with an electric current Ic, the plunger 2b is subjected to a force which is proportionate to the current Ic to apply a force F to push the spool 4 to the right through a push rod 2c. If said current Ic is maintained constant at this moment, the differential between the feed pressure Ps and output pressure Pc can be controlled to be constant. |
