| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a self-holding type solenoid valve capable of valve closing regardless of the degree of consumption of a battery.SOLUTION: The drive voltage of an electromagnetic coil comprises: a first waveform part which maintains a voltage over a predetermined period of time; and a second waveform part which repeats a high voltage state and a low voltage state at a cycle shorter than the predetermined period. In the first waveform part, a voltage Va is maintained over a predetermined period To, so that a large current flows through the electromagnetic coil, and a large magnetic force is generated. On the other hand, in the second waveform part, the high voltage state and the low voltage state are repeated at a short cycle, so that no large current flows through the electromagnetic coil unlike in the first waveform part, and a magnetic force smaller than that in the first waveform part is generated. Therefore, when the battery does not yet consume, if the second waveform part that generates a smaller magnetic force is allowed to close the valve, the self-holding type solenoid valve can be closed by the first waveform part that generates a large magnetic force even when consumption of the battery advances to reduce the drive voltage.</p> |
