EXPANSION DIFFERENCE ABSORBING MECHANISM AND FUEL INJECTION VALVE HAVING THIS EXPANSION DIFFERENCE ABSORBING MECHANISM

摘要

PPROBLEM TO BE SOLVED: To provide an expansion difference absorbing mechanism and a fuel injection valve having this expansion difference absorbing mechanism capable of preventing an overflow from the inside of a chamber when a viscous fluid thermally expands. PSOLUTION: This fuel injection valve 1 operates a needle valve 10 via the viscous fluid and a piston 7 by sliding a cylinder 3 by an actuator 9. An air chamber 40 is communicated via an orifice part 41 (41a and 41b) with a chamber 6 for increasing internal pressure when sliding the cylinder 3 by the actuator 9 among two chambers 5 and 6. A dimension and/or a shape of the orifice part 41 is set so that the expanded viscous fluid passes through the orifice part 41 at a pressure increasing speed slower than a speed generated in the chambers 5 and 6 by the thermal expansion of the viscous fluid without passing the viscous fluid through the orifice part 41 at the pressure increasing speed generated in the chambers 5 and 6 when sliding the cylinder 3 by the actuator 9. PCOPYRIGHT: (C)2006,JPO&NCIPI