Tpr Co., Ltd.

Masahide Hama

Atsushi Nakazawa

Noriaki Ayuzawa

Toshiyuki Shibuya

Yutaka Kitazume

Teppei Oga

Satoshi Minemura

Tetsuji Koyama

In a surface of a wire, a first side surface forming an outer circumferential surface in a piston ring includes a tapered surface and a protruding surface, the protruding surface is divided into a first part and a second part by a first virtual surface extending from the tapered surface, and the first part includes a top and is formed in a protruding shape.

Wire for piston ring, and manufacturing method of piston ring

A combination oil ring includes a pair of upper and lower side rails and a spacer expander arranged there between, the spacer expander including a plurality of upper pieces and lower pieces alternately arranged in a circumferential direction with the pieces axially and circumferentially apart from each other, a coupling piece coupling pieces adjacent to each other, and flange portions formed standing at inner circumferential-side end portions of the upper pieces and the lower pieces so as to press the side rails, and a through hole being formed in the flange portions, wherein side rail support portions that project axially are formed at portions in the circumferential direction of outer circumferential-side end portions of the upper pieces and the lower pieces.

Combination oil ring

A combination oil ring includes a pair of upper and lower side rails and a spacer expander arranged therebetween, the spacer expander including a plurality of upper pieces and lower pieces alternately arranged in a circumferential direction with the pieces axially and circumferentially apart from each other, a coupling piece coupling pieces adjacent to each other, and flange portions formed standing at inner circumferential-side end portions of the upper pieces and the lower pieces so as to press the side rails, and a through hole being formed in the flange portions, wherein side rail support portions that project axially are formed at portions in the circumferential direction of outer circumferential-side end portions of the upper pieces and the lower pieces.

A combination oil ring prevented from freeze up of the side rails and spacer expander, that is, a combination oil ring of the present invention provided with a top and bottom pair of side railsandand a spacer expanderhaving large numbers of top piecesand bottom pieces arranged separated in the axial direction and circumferential direction and alternating in the circumferential direction, connecting piecesconnecting adjoining top piecesand bottom pieces, and ear partsandformed rising up at the inner circumference side ends of the top piecesand bottom piecesfor pushing against the side railsand, in which combination oil ring, groovesandare formed in at least one surfaces of top surfaces of the top piecesand bottom surfaces of the bottom pieces, and through holesandby which the groovesandare communicated are formed in the ear partsand

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Tokyo, Japan

Masahide Hama