| 摘要 |
PROBLEM TO BE SOLVED: To reduce the lowering of a screw effect even when a lip is worn, and to prevent the variation of the screw effect caused by the variation of manufacturing. SOLUTION: This oil seal comprises a deformable elastomer seal lip 5 contacting a rotating shaft and a plurality of ribs 3 formed on a seal surface 2 as the outside inclined surface of the seal lip and having a constant height and width and the rib contacts the rotating shaft for hydrodynamically supporting a seal mechanism. In this oil seal, when an inclination of the rib 3 is set at or larger than three degrees and lower than five degrees and a rib height H is set at or larger than 0.04 mm and lower than 0.055 mm, a circumferential pitch P is set at or larger than 6 mm and lower than 8 mm. When the inclination of the rib is set at or larger than three degrees and lower than five and the rib height H is set at or larger than 0.055 mm and at or lower than 0.07 mm, the circumferential pitch P is set at or larger than 8 mm and at or lower than 10 mm. |
