| 摘要 |
PROBLEM TO BE SOLVED: To provide a combination oil control ring for an automobile engine in which an excellent oil control function can be maintained without fixing a spacer expander and a side rail even in a long-term engine operation.SOLUTION: A combination oil control ring includes two upper and lower side rails, and a spacer expander in which crests and troughs are formed in an axial waveform. The crest and the trough of the spacer expander are constituted by a flange pressing an inner peripheral surface of the side rail, a protrusion supporting the side rail, and an intermediate portion between the flange and the protrusion. The intermediate portion confronting the side rail has at least one groove, and the groove extends in an almost circumferential direction, and is recessed in a radial direction.SELECTED DRAWING: Figure 3(a) |
