| 摘要 |
<p>PROBLEM TO BE SOLVED: To further suppress heat generation of a coil of a solenoid valve and further suppress power consumption.SOLUTION: A solenoid valve comprises: a plunger 3 provided integrally with a valve element 2; energizing means 4 energizing the plunger 3 toward a valve closing position; a coil 5 attracting the plunger 3 by a magnetic force against an energization force of the energizing means 4, and moving the plunger 3 toward a valve opening position; a PWM drive circuit 6 that is a voltage change circuit for changing a voltage applied to the coil 5; and a voltage detection unit 7 for detecting the voltage applied to the coil 5, and the solenoid valve further comprises a control unit 8 exerting a control to apply the voltage to the coil 5 so as to attract the plunger 3 when a signal for opening the valve is received, and a control to reduce the voltage applied to the coil 5 down to an operation maintenance voltage for keeping the plunger 3 at the valve opening position if the voltage detection unit detects a voltage change due to an impedance change that occurs when the coil 5 attracts the plunger 3.</p> |
