| 摘要 |
PROBLEM TO BE SOLVED: To provide a piezo type fuel injection device wherein driving energy of a piezoelectric oscillator is reduced, and a lift generating force and a lift amount of a valve member are secured. SOLUTION: Respective outer diameters of an extended diameter part 33 of the valve member 16 having a needle shape having a circular cross section and a cylindrical auxiliary piston 19 are set smaller than the outer diameter of a columnar main piston 18. When the main piston 18 reduces fluid pressure of back pressure chambers 37, 40, and 50 with contraction of the piezoelectric oscillator 17 and hence the valve member 16 in an nozzle hole blocked state is lifted in the nozzle hole opening direction B of a nozzle hole 30, the auxiliary piston 19 supported on the outer periphery of the extended diameter part 33 moves by a predetermined distance integrally with the extended diameter part 33 and then stops to allow relative movement of the extended diameter part 33. COPYRIGHT: (C)2004,JPO
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