Needle lift damper device of injector for fuel injection and needle lift damping method

摘要

An object of the present invention is to obtain a consistently stable needle lift damping effect in an injector 8b for fuel injection. In an injector 8b that relieves fuel pressure inside a pressure control chamber 37 and lifts a needle valve 36, there are provided a damper member 62 that is slidably mounted to the needle valve 36, a damping chamber 63 formed between the damper member 62 and the needle valve 36, a leak passage 64 for extracting and leaking out the fuel in the damping chamber 63, and a stopper member 41 to restrict the lift position of the damper member 62. Damping of the lift of the needle valve 36 is carried out by extracting and leaking out the fuel in the damping chamber 63 through the leak passage 64. The needle valve 36 functions as a guide for the damper member 62, and prevents vibration of the damper member 62, allowing a consistently stable damping effect to be obtained.