| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve reliability and durability of a bellows 7. Ž<P>SOLUTION: In a piezo actuator for driving a pressure piston, spiral directions of a first spiral projection strip 52 and a first recessed groove 71 formed on a first extension/contraction tube part 41 of the bellows 7 are opposite to spiral directions of a second spiral projection strip 52 and a second recessed groove 72 formed on a second extension/contraction tube part 42, so as to effectively cancel twist generated when two of the first and second extension/contraction tube parts 41, 42 of the bellows 7 are extended and deformed and when two of the first and second extension/contraction tube parts 41, 42 of the bellows 7 are contracted and deformed. Thereby, abrasion in first to third abutment parts disposed along a displacement transmission path extending from a rod to the pressure piston, in particular, in the first and second abutment parts is suppressed. The progress of changes with time of fuel injection performance as a piezo injector can be slowed. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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