| 摘要 |
There is disclosed a method of controlling a hydraulic actuator (1) by using a normally closed solenoid valve (4) and two normally open solenoid valves (5, 6) and selectively actuating them to place the piston (10) of a hydraulic cylinder (1) in position. The normally closed valve (4) is installed in the fluid passage (3a) connecting a hydraulic pressure generator (2) with the hydraulic cylinder (1) and on the side of the generator (2). The normally open valves (5, 6) are connected in series downstream of the normally closed valve (4). At the beginning of the operation of the cylinder (1), the normally closed valve (4) is opened after a lapse of a waiting time long enough for that of the normally open valves (5, 6) which corresponds to the direction of movement of the piston to be closed completely. At the end of the operation of the cylinder (1), the normally open valves (5, 6) are opened after a lapse of another waiting time long enough for the normally closed valve (4) to be closed completely. |
