| 摘要 |
PROBLEM TO BE SOLVED: To reduce a change with the lapse of time of sealing performance, to sufficiently highly keep sealing performance even if an oil seal is used for a shaft having the rough front surface, to use the oil seal in the environment of the wide temperature range, and to miniaturize the whole size. SOLUTION: An oil seal is composed of metallic annular cases 1, 4, rubber covers 2, 3, and grease 5, and a part is formed into a complete axial symmetrical shape except for a protrusion 32. Grease 5 is allowed to flow to a boundary surface among a pleat-like part 21 of the rubber cover 2, a pleat-like part 31 of the rubber cover 3 and a shaft 6 to lubricate the boundary surface, and a function as a sealing surface is provided on the boundary surface. Grease 5 to be rotated with the shaft 6 is allowed to the inner walls of the rubber covers 2, 3. The grease 5 is always supplied to the outer peripheral surface of the shaft 6 by a vortex to be generated when the flow is brought in contact with the protrusion 32, the outer peripheral surface of the shaft 6 is always covered with grease 5, and bubbles are not formed on the outer peripheral surface of the shaft 6. |
