| 摘要 |
PROBLEM TO BE SOLVED: To provide an oil ring which regulates the rotation of side rails, and secures uniform surface pressure over entire peripheries of external peripheral faces of the side rails.SOLUTION: An oil ring comprises side rails 30A, 30B which are held along sidewalls 16, 17 opposing an oil ring groove 15 of a piston 10, and an expander 21 which is sandwiched between the side rails 30A, 30B, and presses the side rails 30a, 30B to the outside of a radial direction. Bent-formed engagement protrusions 39 are formed at the side rails 30A, 30B, engaged with lock grooves 16a, 17a which are formed at the sidewalls 16, 17, respectively, and regulate rotation of the side rails. Since the engagement portions 29 are bent-formed in a region which is separated from internal peripheral faces 32 and external peripheral faces 33 of the side rails, the engagement protrusions are push-pressed by an ear part 25 which pressure-contacts with entire peripheries of the internal peripheral faces 32 of the side rails 30A, 30B, and surface pressure for pressing the external peripheral faces 33 to an internal peripheral face 1a of a cylinder bore 1 is secured.SELECTED DRAWING: Figure 3 |
