FUEL INJECTION VALVE

PROBLEM TO BE SOLVED: To realize a fuel injection valve which secures safety in actuation by inhibiting the uneven abrasion of a sliding face of an operating piston, and has the stabilized injection characteristic. SOLUTION: An operating piston 5 is slid by increasing and decreasing the pressure of a piezo-pump chamber 43 by the expansion and contraction of a piezo actuator 1 to drive a valve 61 for opening and closing a drain passage 33. A spiral groove part 53 is formed on an end face of the operating piston 5 opposite to the drain passage 33, and the torque in the circumferential direction is applied to the operating piston 5 by fluid power of the fuel flowing out when the drain passage 33 is opened. As the operating piston 5 is rotated as needed, the uneven abrasion is not generated even when a clearance to a cylinder 51 is reduced, and the injecting performance is improved. COPYRIGHT: (C)2004,JPO