摘要 |
A bearing unit includes two pairs of bearings, a housing for housing the bearings and a flange through which the shaft is inserted. In order to prevent the invasion of cutting chips or cutting oil into the bearings, the flange is provided with a circumferential groove on the inner surface of the flange, and an air supply port which opens in the circumferential groove for introducing compressed air to the groove. The axial direction of the supply port is parallel to a tangent of the shaft, so that the compressed air is effectively introduced in the circumferential direction of the shaft. Therefore, the air blow created by the compressed air in the clearance becomes uniform along the circumference of the shaft, which enables to effectively prevent the invasion of cutting chips and cutting oil.
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