Compact seal

Abstract

A compact seal assembly fits into the end of a bearing and effectively retains grease within the bearing while excluding contaminants, notwithstanding operation of the bearing within a hostile environment. The seal assembly includes a shield having an axial mounting portion which fits over the inner race of the bearing and an outwardly directed flange, as well as a smooth sealing surface on both. The seal has a case which fits into the outer face of the bearing and an elastomeric sealing element which establishes several barriers along the sealing surface of the shield. The first barrier exists at a pumping labyrinth which encircles, but is spaced outwardly from the axial segment of the sealing surface where it is exposed to the interior of the bearing. The labyrinth contains wedge-shaped cavities which pump the grease back toward the interior of the bearing. The next barrier is along a primary dirt lip which actually contacts the axial portion of the sealing surface, it being urged against that surface by a garter spring. Another barrier exists along a secondary dirt lip which contacts the radial portion of the sealing surface, that is the portion on the flange of the shield. The primary dirt lip lies between the pumping labyrinth and the secondary dirt lip, with these portions of the sealing element being separated by grooves. Rings of grease occupy the grooves, and this grease extends outwardly to and adheres to the sealing surface so as to establish still more barriers along the sealing surface.