| 摘要 |
PROBLEM TO BE SOLVED: To improve reliability of a device by preventing intrusion of foreign matter into a hydraulic drive part in an injector and driving a nozzle needle with good controllability. SOLUTION: Displacement generated in a piezoelectric stack 21 of a piezoelectric actuator 2is transmitted via a displacement magnification part 3 comprised of a large diameter piston 31, a hydraulic chamber 32 and a small diameter piston 33 to move the nozzle needle up and down. A fuel passage 12 is formed in the large diameter piston 31 in a moving direction and supplies working oil to the hydraulic chamber 32 via a check valve 34. A filter member 15 having sufficiently small filter holes is provided in the fuel passage 12 and surely captures the foreign matter in fuel flowing in the same to prevent drop of sliding properties due to bite of the foreign matter between a cylinder member 36 and the small diameter piston 33. COPYRIGHT: (C)2007,JPO&INPIT
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