| 摘要 |
PROBLEM TO BE SOLVED: To provide a three-piece oil ring for achieving improved sealing performance and reduced lubrication oil consumption even if the ring has a low tensile force and a small thickness without causing a stick, and to provide a combination of the three-piece oil ring and a piston. SOLUTION: The three-piece oil ring comprises a spacer expander 10 and two siderails. The spacer expander 10 has lugs 13 protruded from radially inward sides to the axial direction for thrusting inner peripheries of first and second siderails and having inclined faces on radially outward sides, and siderail supporting portions 14 protruded from the radially outward positions to the axial direction for supporting axial end faces of the first and second siderails. A lug angle as an angle between the inclined face 13a of the lug portion on the radially outward side and an axial center is 10-20°, and a ratio 2X/Y of a total distance 2X adding up axial protrusion distances X of the siderail supporting portions to a distance Y between the axial end faces of both the lugs is 0.04-0.15. COPYRIGHT: (C)2007,JPO&INPIT
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