| 摘要 |
PURPOSE:To lessen the action delay of a solenoid coil current to signals during the action of pilot valves and enlarge the effective region of a pulse width modulation rate by providing detectors for detecting the solenoid coil current and returning the solenoid coil current to solenoid coil current controllers, thus controlling the solenoid coil current. CONSTITUTION:During pulse width modulating action, ascending pilot valves 6, 7 perform the feedback control of the solenoid coil current of solenoid coils 6', 7' detected at solenoid coil current detectors 12', 13'. With such feedback control, the rising delay of the solenoid coil current to signals is lessened, and the change in action delay due to the fluctuation of solenoid coil voltage becomes less, as well as the effective range of a modulation rate is enlarged. |
