Hitachi Astemo Ltd.

Ryohei Matsutake

Kenichi Gunji

Masashi Sugaya

Masato Higuma

Yuta Yanagisawa

Yuki Sugiyama

Provided is a prestroke adjustment method for a fuel injection valve capable of reducing variations in a prestroke amount regardless of the level of machining accuracy of a component. The prestroke adjustment method adjusts a prestroke amount Dof a fuel injection valveincluding a gap forming memberthat forms a gap Gdefining a prestroke between a valve memberand engagement portionsandof a movable coreby a second portionabutting on the movable corein a state where a first portionis positioned at a reference positionof the valve memberIn the prestroke adjustment method, a load L in the direction from the first portiontoward the reference positionof the valve memberis applied to the gap forming memberassembled to the valve memberto plastically deform the gap forming memberthereby shortening the relative length between the first portionand the second portionand setting the prestroke amount Dto the target value T

Prestroke adjustment method for fuel injection valve

An object of the present invention is to provide a working method of an orifice, which has excellent working accuracy and high productivity in order to work an inclination portion (tapered portion) on the entire circumference of an inner wall of an orifice. Therefore, a working method of an orifice includes a first step of forming an orifice holein an orifice forming member, a second step of pressing a downstream end surface of the orifice forming member in which the orifice holeopens, in a direction toward an upstream side of the orifice holeby a punchhaving a cutting blade portionlarger than a cross section of the orifice hole. The second step causes a material of the orifice forming member to flow from an entire circumference at the downstream end portion of the orifice holeto an inside of the orifice holeto form a cross-sectional area reduction portionin which a cross-sectional area of the orifice holeis reduced from an upstream side to a downstream side.

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Hitachinaka, Japan

Ryohei Matsutake