| 摘要 |
A hydrodynamic seal (B) suitable for closing the end of a tapered roller bearing (A) includes a seal case (24) which is pressed into a counterbore (6) at the end of the bearing cup (2) and an elastomeric sealing element (26) having a primary lip (34) and secondary lip (36) which co-operate with a sealing surface (14) on the thrust rib (12) of the bearing cone (8) to effect a live seal along that surface. The primary lip (34) is spaced from the sealing surface of the cone thrust rib and has pumping cavities which open both toward the sealing surface and toward the interior of the bearing. Moreover, they are configured to pump lyubricant that enters them back tpward the interior of the bearing. An annular space exists between the primary and secondary lips (34,36) and the pumping cavities also open into this space at small vent apertures, so that any increase in pressure within the interior of the bearing is transmitted through the pumping cavities to the annular space. The secondary lip actually contacts the sealing surface of the thrust rib, but is oriented oblique to that surface, so that a pressure increase transmitted to the annular cavity causes the secondary lip to lift slightly away from the sealing surface and relieve the increase in pressure. |
