| 摘要 |
PURPOSE:To perform a precise synchronizing motion, by a method wherein a hole is formed in a piston head, a conductor lever, insulated from a head, is inserted into the hole, and a cylinder is corrected for drive by comparing a voltage proportioning an electrostatic capacity produced between the hole and the lever. CONSTITUTION:A detecting long hole 4 is formed in the head side of the piston 2 of a hydraulic cylinder 1, a detecting conductor lever 5, inserted into the detecting long hole 4 with a clearance, is mounted in a head 3 in a manner to be insulated from the head 3, and a voltage, proportioning an electrostatic capacity value produced between the inner peripheral surface of the detecting long hole 4 and the outer peripheral surface of the detecting conductor lever 5, is outputted from a capacity and voltage converting circuit 6. The sliding action of a reference hydraulic cylinder 1a causes changing of an electrostatic capacity value, also causes changing of an output from a circuit 6a to compare them with an output voltage from a circuit 6b of one hydraulic cylinder 1b by means of a voltage comparing circuit 7, and if a deviation is caused, a deviation voltage is outputted. A variable valve, a pump and the like are corrected by a control drive circuit 8 corresponding to said output for drive so that the deviation voltage is brought to 0. |
