| 摘要 |
<p>PURPOSE:To prevent fixing of a hydraulic element such as a spool or the like by outputting a signal to a voltage/current converter as the control signal, in which the larger is a deviation signal the larger ON/OFF time ratio increases, so as to excite a solenoid of various control valves. CONSTITUTION:A command signal Vo and an AC signal Vd, having a dither frequency, are added by an adder 10 generating an overlapped signal calculated in its difference from a feedback signal Vf from a solenoid 1 through an LP filter 5 by a subtractor 6 and compared with a signal Va, having a fixed frequency not less than a maximum frequency of the command signal Vo from an oscillator 9, by a comparator 8, and generating a pulse width modulated control signal Vc, in which the larger is a deviation signal the larger ON/OFF time ratio increases, driving the solenoid 1 through a switching element 3. Thus, while preventing fixing of a spool or the like in a solenoid control valve, a hydraulic system, including the control valve, can be controlled with a high response and a high gain.</p> |
