| 摘要 |
PURPOSE:To keep the quantity of oil leakage about constant independently of the number of revolutions of an engine. CONSTITUTION:In an oil seal 20 where an elastic body 22 such as rubber is coveredly attached to a core 21 whose half section is about L-shaped cylindrical, the tip of a seal lip 23 being partially the elastic body 22 is made sharp, and a rising part 25 which rises radially inward and has axially fixed width is provided near the tip of the inside inclining face (an inclining face on a side where the seal lip comes into contact with a valve stem) of the seal lip 23. The surface of the rising part 25 is irregularly formed. The irregularity of the rising part 25 forms a passage having a minute space between the rising part 25 and the valve stem, and oil leakage occurs through the above passage. |
