Hitachi Automotive Systems, Ltd.

Hitachi Astemo Ltd.

Yuta Yanagisawa

Kiyotaka Ogura

Masato Higuma

Atsushi Takaoku

Kenichi Gunji

Ryohei Matsutake

Yuki Sugiyama

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.

Working method of orifice and fuel injection valve

It is important not to form the partial bump in the collision structural part, however the fixed core and the movable core are relatively inclined due to an accumulation of tolerances and therefore even if each collision structural part of the fixed core and the movable core in formed in a flat shape, the fixed core and the movable core are contacted with not the whole of the collision structural parts but a part of the collision structural parts at the moment of the collision. In a case in which the collision structural part is formed in a ring shape or an intermittent ring shape, the fixed core and the movable core are contacted with each other at outer peripheral parts. Thus, when the fixed core and the movable core are collided with each other, a high stress is applied to the outer peripheral parts contacted first. Accordingly, the shape of the outer peripheral parts of the collision structural parts is important, however since such a part, which is a tiny protruding shape, requires high processing accuracy, to reduce stress occurred during collision while keeping productivity is difficult. In the present invention, an R-shaped part and a flat part are provided in order from an outer peripheral side of a collision structural part. Further, the R-shaped part and the flat part are connected in a tangent manner.

Electromagnetic valve

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Hitachinaka, Japan

Yuta Yanagisawa