| 摘要 |
This bearing apparatus includes a shaft portion, a sleeve portion, and a fluid arranged between the shaft portion and the sleeve portion. A thrust dynamic pressure portion is filled with the fluid, and a surface of the fluid is defined in a seal portion. The thrust dynamic pressure portion includes a dynamic pressure generation portion including thrust dynamic pressure grooves, an intermediate portion arranged outside of the dynamic pressure generation portion and including an annular groove in the shape of a circular ring, and a discharge portion arranged outside of the annular groove and including discharge grooves. The annular groove is arranged to have a depth smaller than a minimum radial width of the seal portion. This makes it easier for any air bubble in the thrust dynamic pressure portion to travel into the seal portion in accordance with a flow of the fluid caused in the discharge portion to be discharged outward. This reduces the likelihood that any air bubble will stay in the vicinity of the dynamic pressure generation portion. |
| 主权项 |
1. A bearing apparatus comprising a shaft portion, a sleeve portion, and a fluid arranged between the shaft portion and the sleeve portion, wherein
the shaft portion includes:
a columnar portion arranged to extend along a central axis;an annular portion arranged to extend radially outward from the columnar portion; anda tubular portion arranged to extend from the annular portion to one axial side; the sleeve portion is arranged on the one axial side of the annular portion, radially outside of the columnar portion, and radially inside of the tubular portion; the shaft portion and the sleeve portion have a gap therebetween, the gap including:
a radial dynamic pressure portion defined in a gap between an outer circumferential surface of the columnar portion and an inner circumferential surface of the sleeve portion;a thrust dynamic pressure portion defined in a gap between a first thrust surface and a second thrust surface, the first thrust surface being an end surface of the annular portion on the one axial side, the second thrust surface being an end surface of the sleeve portion on another axial side; anda seal portion defined in a gap between an inner circumferential surface of the tubular portion and an outer circumferential surface of the sleeve portion; each of the radial dynamic pressure portion and the thrust dynamic pressure portion is filled with the fluid; the seal portion has a surface of the fluid defined therein; the thrust dynamic pressure portion includes:
a dynamic pressure generation portion including a plurality of thrust dynamic pressure grooves defined in one of the first and second thrust surfaces, each thrust dynamic pressure groove extending from a radially inner side to a radially outer side;an intermediate portion arranged radially outside of the dynamic pressure generation portion, and including an annular groove in a shape of a circular ring with the central axis as a center defined in one of the first and second thrust surfaces; anda discharge portion arranged radially outside of the annular groove, and including a plurality of discharge grooves defined in one of the first and second thrust surfaces, each discharge groove extending from the radially inner side to the radially outer side; and the annular groove is arranged to have a depth smaller than a minimum radial width of the seal portion. |
