| 摘要 |
PURPOSE:To improve radial and axial sealing property in an oil ring assembly for pressing oil rings against a cylinder wall with elasticity of an expander by raising rigidity of the upper and lower oil rings and surface pressure of same against the inner wall of the cylinder. CONSTITUTION:An oil ring assembly A is constituted from upper and lower oil ring bodies 5, 6 and an expander 7. The upper and lower oil rings 5, 6 are formed on raidally central portion with a thick wall portion 11 which is formed at circumferential intervals with a plurality of oil grooves 18 to raise rigidity, particularly axial one, i.e. ridigity in the sliding direction. Further, the oil ring bodies 5, 6 is provided on the outer periphery with thin wall protions 12, 13 to raise surface pressure to the inner wall surface of cylinder bore 2. On the other hand, the expander 7 applies uniformly radially tension to the whole circumferece of the oil ring bodies 5, 6 with the top portions 19 of the wave form to press the oil ring bodies 5, 6 in the sliding direction with spring pieces 20 so that the respective flat side surfaces of the bodies 5, 6 are pressed uniformly against the upper and lower surfaces of oil ring groove 4. |
