OUTER RING ROTATION BEARING

It is an object of the present invention to prevent grease from leaking from an outer race rotation bearing in which an outer race rotates at a high speed so as to extend the service life of the bearing. In the outer race rotation bearing, a mounting portion (9) made of a rubber is fitted in each annular groove (7) of an outer race (2). A pair of seals (6) are provided which close the respective axial ends of an annular space (5) defined between an inner race (1) and the outer race (2). Each of the seals (6) has a grease leakage preventing lip (elastic lip) (13) which protrudes toward the interior of the bearing, and which is kept in close contact with a groove edge portion (14) of the annular groove (7) from the inner peripheral side of the outer race (2). In this arrangement, when the seals (6) are pressed by grease to which centrifugal force is applied and thus are moved axially outwardly, the grease leakage preventing lips (13) of the respective seals (6) function as lids to close the gaps generated between the mounting portions (9) and the annular grooves (7), thereby making it possible to prevent grease from leaking through these gaps.