| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a main spindle device effectively suppressing temperature rise by heat evolution from a free side bearing, achieving lifetime extension of the free side bearing, i.e., lifetime extension of the main spindle device, and capable of improving processing precision.SOLUTION: A cooling path 40 into which a cooling medium can flow is formed between an outer peripheral surface 16b of a bearing sleeve 16 to which free side bearings 14 and 14 are internally fitted, and an inner peripheral surface 33a of a rear housing 33. The cooling path 40 comprises a plurality of spiral grooves 41A and 41B formed on the outer peripheral surface 16b of the bearing sleeve 16, and formed between one end side to the other end side in the axial direction of the sleeve on the outer peripheral surface of the sleeve. The housing includes a plurality of supply ports 51A and 51B which are communicated with one ends of respective spiral grooves, and to which the cooling medium is supplied, and a plurality of discharge ports 52A and 52B which are communicated with the other ends of respective spiral grooves, and from which the cooling medium flowing in the spiral groove is discharged.</p> |
