| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve hermetic sealing performance of a bearing for use in a dental air turbine.SOLUTION: Provided is an angular contact ball bearing configured so that any one of an inner circumferential portion of an outer ring and an outer circumferential portion of an inner ring includes a shoulder formed on one side in an axial direction with respect to an orbital surface thereof; and a counter bore formed on the other side in the axial direction, the other portion out of the inner circumferential portion of the outer ring and the outer circumferential portion of the inner ring includes a pair of shoulders formed on both sides across an orbital surface thereof in the axial direction, the outer ring further includes a hermetic seal portion extending radially from the shoulder toward the inner ring, and opposed to the outer circumferential portion of the inner ring, the hermetic seal portion and the outer circumferential portion of the inner ring constituting a labyrinth structure.</p> |
