PISTON RING AND MANUFACTURING METHOD THEREOF

PROBLEM TO BE SOLVED: To provide a piston ring that reduces frictional force between a ring and a cylinder inner wall and shows an excellent lubrication characteristic while maintaining excellent gas seal characteristic and oil consumption characteristic, and a manufacturing method thereof.SOLUTION: A piston ring has an outer peripheral slide surface covered with a hard film, has many recess parts, and is formed into a barrel face shape. The recess parts comprise first and second recess parts with different depths. The first recess parts are independent from each other and become deeper than the second recess parts, and a cross sectional area of the first recess part substantially parallel with the outer peripheral surface decreases toward a depth direction.SELECTED DRAWING: Figure 4 【課題】優れたガスシール特性とオイル消費特性を維持した上で、リングとシリンダ内壁間の摩擦力を低減し、優れた潤滑特性を示すピストンリング及びその製造方法を提供する。【解決手段】外周摺動面に硬質皮膜を被覆し多数の凹部を有するバレルフェイス形状のピストンリングとし、前記凹部は深さの異なる第1及び第2の二種類の凹部から構成し、前記第1の凹部は、個々に独立し、前記第2の凹部よりも深く、前記外周面に略平行な断面の面積が深さ方向に減少するような凹部とする。【選択図】図4