| 摘要 |
PROBLEM TO BE SOLVED: To provide an oil seal enhancing oil sealing performance by efficiently returning oil tending to leak. SOLUTION: This oil seal has a circular seal lip 1 having almost an wedge- shaped cross section, whose sharp end edge on the inner circumference side comes in contact with a shaft 2. Plural first rib groups 8 each comprising plural ribs 81, 82, etc., returning oil tending to leak when the shaft 2 rotates in one direction or relatively rotates and plural second rib groups 9 each comprising plural ribs 91, 92, etc., returning oil tending to leak when the shaft 2 reversely rotates or relatively rotates are alternately installed in the oil seal. The first rib group 8 is formed so as to change little by little the heights of ribs so that the ribs positioned on the front side in the rotation direction when the shaft 2 rotates in one direction or relatively rotates become gradually higher, and the second rib group 9 is formed so as to change little by little the heights of ribs so that the ribs positioned on the front side in the rotation direction when the shaft 2 reversely rotates or relatively rotates become gradually higher. |
