| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an actuator capable of delicately and accurately controlling oil amount and oil pressure. <P>SOLUTION: A pair of electric ball screw mechanisms 26 for letting a first piston 25 advance and retract through a ball nut 24 screw-fitted in a ball screw 23 and having different screw pitch are arranged in series on the same axis by letting the first pistons 25 oppose mutually through a first pressure chamber 27. A third piston 31 advances by a second piston 29 advancing by oil pressure in a second pressure chamber 28 communicating with the first pressure chamber 27 to push hydraulic fluid out of a third pressure chamber 32 in a hydraulic fluid pressure feeding mechanism 33. Each electric ball screw mechanism 26 is arranged in parallel to constitute this actuator 20. <P>COPYRIGHT: (C)2004,JPO</p> |
