| 摘要 |
A seal assembly for closing the end of a bearing includes a seal (40) and a shield (42) to which the seal is bonded. The shield has an axially directed mounting portion (50), an axially directed overhang (56) and a radial end wall (54) between the mounting portion and overhang. The seal has a pumping labyrinth (70) presented toward the mounting portion, yet spaced from it, a dirt lip (72) directed obliquely toward and contacting the mounting portion, and a secondary lip (74) directed obliquely toward but normally spaced from the overhang. The labyrinth is exposed toward the interior of the bearing and has pumping cavities (86) which impel lubricant back into the bearing. Between the dirt and secondary lip is an annular groove (78) containing a ring of lubricant grease which extends up to the radial wall and forming a barrier to the ingress of contaminants. If the ring of lubricant becomes temporarily pressurized, it deflects the secondary lip (74) against the overhang (56) to prevent excessive leakage, the pressure being relieved through vent notches (112) in the contacting edge of the lip. |
