| 摘要 |
PURPOSE:To obtain an opening and closing valve of fluid formed in a small size further provided with a very high speed response, by using an electrostrictive element and utilizing an electrostrictive effect so as to drive a spool valve. CONSTITUTION:If voltages is applied to a laminated electrostrictive element (PZT) 3, the PZT extends by its characteristic moving a piston 5 in a direction decreasing volume of the first pressure oil chamber 9 while increasing pressure in its inside, and a spool valve 10 moves by a decrease of the volume to a side of the second pressure oil chamber 16. Then an opening and closing valve, connecting a branch passage 15a of an oil passage 15 with a recessed part 8a, allows high pressure working fluid in the second pressure oil chamber 16 to successively flow at a high speed to the oil passage 15, recessed part 8a, outlet passage 19 and an outlet hole 20. The downstream side of a throttle part 17 generates a low pressure as compared with the upstream side, and the opening and closing valve, allowing high pressure oil in the first pressure oil chamber 9 to flow leaking through a clearance L and moving the spool valve 10 to a side of the first pressure oil chamber 9 by a pressure difference between the first and second pressure oil chambers 16, 9 and the tension of a spring 22, cuts off communication of the branch passage 15a with the recessed part 8a.
|
