| 摘要 |
PROBLEM TO BE SOLVED: To prevent a step motor and a drive circuit from heating and increasing the load by holding a valve body on a damping characteristic set position by a holding mode in which a driving quantity is smaller than that at a driving mode. SOLUTION: It is judged whether a step motor is driven or not (ST1), for example, the case of changing from low damping characteristic to high damping characteristic is set to be normal rotation, then in the reverse case it is reverse rotation, the normal or reverse rotation is discriminated (ST2), and in order to rotationally move a valve body to an optional damping characteristic set position (a prescribed set angle), control to supply driving voltage required for driving the step motor is carried out (ST3), thereafter control to output holding voltage for holding it (ST4) is carried out. The holding voltage is lower than the driving voltage at a driving mode, and it is concretely a voltage value of the degree necessary for holding the step motor on the present position against torque variation such as pressure change of fluid acting on the valve body. |
