Nippon Piston Ring Co., Ltd.

Toyota Jidosha Kabushiki Kaisha

Stt Inc.

Hideshi Hitosugi

Kenji Arai

Keishi Nanno

Tomotaka Kariya

Makoto Tsuruta

Hideo Negishi

Kazutomo Takahashi

Shiro Shibata

Tomoaki Abe

Yasuyuki Murata

Masataka Kawasaki

Ryosuke Kamata

Kazumoto Takahashi

Mamoru Miyamoto

Toru Tsukui

Hideyo Iwama

Provided is a combined oil ring that further reduces engine oil consumption. A combined oil ring attached to an oil ring groove of a piston includes: a pair of upper and lower side rails each formed into a flat annular shape, and having a slide contact part that comes into sliding contact with a cylinder; and a spacer expander arranged between the pair of upper and lower side rails. In at least the upper side rail of the pair of upper and lower side rails, a cross-sectional shape of the slide contact part along an axial direction of the piston is a tapered shape linearly spreading from upper to lower parts of the piston; the tapered shape is at an angle of 5 to 30 degrees with respect to a central axis of the spacer expander, and has a vertex of the tapered shape within 0.15 mm from a lower end of the side rail; and a part closer to the lower end than the vertex is formed into a curved shape having a curvature of R0.01 to 0.5.

Combined oil ring

A combined oil ring in which carbon sludge and the like are not deposited between side rails and a spacer expander even if an internal combustion engine is operated for a long period of time. The combined oil ring includes an outer circumferential end portion of a space forming part and a continuous part that are closed and not open toward the outer circumferential side, thereby reducing carbon sludge deposits.

A combined oil ring that reduces deposits between side rails and a spacer expander there between. The spacer expander includes: upper pieces and lower pieces that are alternately arranged in a circumferential direction to be spaced apart in an axial direction and the circumferential direction; coupling pieces that respectively couple the adjacent upper and lower pieces; and ear parts that erect in an inner circumferential end portion of the upper and lower pieces and push the side rails. At least one of an upper surface of each upper piece and a lower surface of each lower piece has a groove formed thereon. Ear parts have a through-hole with which the groove is communicated and a distance along the axial direction between an upper or lower surface of each ear part at a top thereof and a deepest portion of the groove is at least 0.22 mm.

There is provided a piston ring which can effectively prevent aluminum adhesion phenomenon to the piston ring. The piston ring includes a piston ring main body and a surface coating film on either upper or lower surface of the piston ring main body, or both the upper and lower surfaces of the piston ring. The surface coating film includes heat-resistant resin and copper based powder contained therein.

Piston ring

It is a main object of the present invention to provide an oil ring which is capable of reducing sliding friction even in a high speed revolution region of a piston, and capable of reducing the consumption of oil. To achieve the object, the present invention provides an oil ring which is formed into cross-section substantially of an I-shape that two rails are connected at a columnar portion thereof, wherein a sliding projection formed in each of the two rails comprises an outer side surface of sliding projection which forms an outer portion of the sliding projection, a inner side surface of sliding projection which forms an inner portion of the sliding projection, and a sliding surface which slides on a cylinder inner wall and forms a tip end of the sliding projection;

Oil ring

A compression piston ring capable of reducing excessive surface pressure at a gap and adjacent portion thereto during engine operation, and capable of being produced at a low cost. The compression piston ring has generally circular shape without any notched portion. The compression piston ring has a dimensional requirements in that d /a ranges from 40 to 60, and d /h ranges from 30 to 55, in which d represents an inner diameter of the piston ring, a represents a radial length between inner and outer peripheral surfaces of the piston ring, and h represents an axial length of the outer peripheral surface. The compression piston ring is particularly available as a first compression piston ring for a supercharging type diesel engine providing high engine pressure.

Growing community of inventors

Saitama, Japan

Hideshi Hitosugi