| 摘要 |
PROBLEM TO BE SOLVED: To reduce the sliding resistance of a seal lip with a rib for an oil seal. SOLUTION: In this oil seal 1, an annular seal member 11 is provided with the seal lip 16 in contact with the outer circumference 3 of a rotary shaft 2 in its inner circumferential part 13. An air-side slope surface 22 extending from the tip edge 21 of the seal lip 16 is formed with ribs 24 in several parts along the circumferential direction, and each rib 24 inclines diagonally to the circumferential direction so as to reduce the sliding resistance of the lip. An undulating part 30 formed of fine many recess parts 31 distributedly formed over the whole circumference is provided in a range 25 adjacent to the tip edge 21 of the seal lip 16 between the adjoining ribs 24. This constitution can prevent the part between the ribs 24 of the seal lip 16 from abutting on all the outer circumference 3 of the rotary shaft to further reduce the sliding resistance. The lubricating operation of the oil retained in the recess part 31 also further reduces the sliding resistance. |
