| 摘要 |
<p>PURPOSE:To reduce electric resistance to 1/4 conventional resistance and to increase current values to be supplied to respective coils and driving force to be generated by switching the electric connection of the coils from serial connection to parallel connection at the time of generating emergency requiring large driving power. CONSTITUTION:At the time of normal flow rate control, the common terminal 102a of a switch 102 is connected to an NC terminal 102b and the common terminal 103a of a switch 103 is connected to an NC terminal 103b. At that time, the driving current of a controller 41 flows a coil 27, the switch 102, the switch 103, and a coil 26 and then returns to the controller 41. If a bubble spool 4 is locked due to dust or the like included in hydraulic oil and can not be restored to a normal state, the common terminal 102a of the switch 102 is connected to a NO terminal 102c and the common terminal 103a of the switch 103 is connected to a NO terminal 103a. Thereby, attracting power is increased and the spool 4 can be restored to the normal state.</p> |
