Denso Corporation

Kenichi Niinuma

Katsumi Mori

Tetsuya Yoshimura

A cylinder body includes a cylinder hole and a discharge flow passage. The cylinder hole receives a plunger and forms a pressurizing chamber in one axial end portion thereof. The discharge flow passage is connected to the pressurizing chamber and is adapted to guide and discharge the pressurized fuel from the pressurizing chamber to an outside of the housing. A connection opening of the discharge flow passage is formed in a hole wall of the cylinder hole. A pressure is applied to a predetermined prestressing subject area in the hole wall of the cylinder hole and a passage wall of the discharge flow passage through autofrettage to generate a residual compression stress in the predetermined prestressing subject area and thereby to form a prestressed area of a final product. The prestressing subject area includes an inner peripheral edge of the connection opening.

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Kariya, Japan

Kenichi Niinuma