Bearing with magnetic fluid seal

摘要

Provided is a bearing with a magnetic fluid seal reliably maintaining sealing of a rolling element section in the bearing and having a structure ensuring high productivity. In a bearing with a magnetic fluid seal according to the present invention, a plurality of rolling elements 7 are disposed between an inner ring and an outer ring, and a ring-shaped magnet is arranged at an opening side of the inner and outer rings so as to retain magnetic fluid, so that the plurality of rolling elements are sealed. The magnet is magnetized so that magnetic poles are oriented in an axial direction. A ring-shaped pole plate is arranged to be in contact with an outer side surface of the magnet in the axial direction. Outer-ring-side magnetic fluid is retained between the outer ring and the magnet, and inner-ring-side magnetic fluid is retained between the inner ring and the pole plate.

主权项

1. A bearing comprising:
an inner ring; an outer ring; a plurality of rolling elements positioned between the inner ring and the outer ring; a ring-shaped magnet positioned between the inner ring and the outer ring at an axially outer side of the plurality of rolling elements and magnetized such that magnetic poles are oriented in an axial direction; a ring-shaped plate arranged so as to be in contact with an axially outer side surface of the ring-shaped magnet; inner-ring-side magnetic fluid retained at least between the inner ring and the ring-shaped plate and outer-ring-side magnetic fluid retained in a gap formed between an outer peripheral surface of the ring-shaped plate and an inner peripheral surface of the outer ring, wherein a step is formed in an inner circumferential surface of the outer ring such that a distance between the inner and outer rings is greater at an axially outer side than at an axially inner side, wherein the ring-shaped magnet is attracted to a step surface of the step by a magnetic force, and wherein an axially outer side surface of the plate is retreated such that at least an inner-ring-side end thereof is axially inside an axially outer side surface of the inner ring.