Tpr Co., Ltd.

Yutaka Kitazume

Tomoyuki Sato

Kiyoyuki Kawai

Noriaki Ayuzawa

Masahide Hama

Takatsugu Iwashita

Tetsuya Nango

Haojie Fu

An object of the present invention is to provide a sliding member coated with a DLC coating in which microfractures on the sliding surface thereof due to the progression of cracks are less likely to occur, and in which an increase in abrasive wear can be reduced. The present invention achieves the above-mentioned object by a sliding member having a DLC coating on the outer peripheral surface thereof, wherein an S band derived from spbonding is observed in the DLC coating in addition to a G band derived from the graphite structure and a D band derived from the defects of the graphite structure, and these bands satisfy specific relationships.

Sliding member

An object of the present invention is to provide a sliding member coated with a DLC coating in which microfractures on the sliding surface thereof due to the progression of cracks are less likely to occur, and in which an increase in abrasive wear can be reduced. The present invention achieves the above-mentioned object by a sliding member having, on the outer peripheral sliding surface thereof, a DLC coating in which the amount of plastic deformation work as measured by a nanoindentation test is within a specific range.

The present invention addresses the problem of providing a piston ring covered with a DLC coating that has excellent wear resistance and shows a low attacking property on a cylinder bore sliding surface. The problem is solved by a piston ring which is used in the presence of an engine lubricating oil and includes a DLC coating on an outer peripheral sliding surface. The DLC coating has an spcomponent ratio of 0.5 to 0.85 as determined from a TEM-EELS spectrum obtained by a combination of a transmission electron microscope (TEM) and electron energy loss spectroscopy (EELS), as well as a coating hardness of 12 GPa to 26 GPa and a Young's modulus of 250 GPa or less as measured by a nanoindentation method.

Piston ring

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

Yutaka Kitazume