| 摘要 |
A cooling passage (40) through which a cooling medium can flow is formed between the inner peripheral surface of a rear housing (33), and the outer peripheral surface of a bearing sleeve (16) having a free-side bearing inserted therein. The cooling passage (40) is formed in the outer peripheral surface of the bearing sleeve (16), and is provided with: a first annular groove (41A) provided to one-end side of the sleeve in the axial direction; a second annular groove (41B) provided to another-end side of the sleeve in the axial direction; and a single helical groove (47) which has one end thereof connected to the first annular groove, and another end thereof connected to the second annular groove. The cooling medium is supplied to the first annular groove, flows through the cooling passage, and is discharged from the second annular groove. |
