In order to prevent leaking of lubricant, the bearing device includes a rolling bearing having an outer ring and an inner ring, a shaft fixed to the inner ring, and a sleeve fixed to the outer ring. A flange part is formed on at least one end part of the shaft. The flange part includes a disk part extending from the shaft toward an outside in a radial direction and a cylindrical part extending from the disk part along an axial direction. The cylindrical part is disposed at an outside of the outer ring, and a labyrinth gap which bends at two places is formed by gaps.
1. A bearing device comprising:
a rolling bearing having an outer ring and an inner ring;
a shaft fixed to the inner ring;
a sleeve fixed to the outer ring;
a flange formed on at least one end part of the shaft, the flange comprising:
a disk part extending from the shaft toward an outside in a radial direction; and
a cylindrical part disposed at an outside of the outer ring and extending from the disk part along a direction of an axis;
an extending part formed on the sleeve that faces an outer or inner circumferential surface of the cylindrical part;
a step part formed in the sleeve as a result of the extending part being formed;
a labyrinth gap that bends in at least two places, the labyrinth gap being formed by:
a first gap formed between an end surface of the cylindrical part and the step part;
a second gap faced by the inner circumferential surface of the cylindrical part; and
a third gap formed between the outer ring and the disk part; and
another gap further formed between the outer circumferential surface of the cylindrical part and an inner circumferential surface of the extending part, or between the disk part and an end surface of the extending part.
2. A hard disk drive comprising a bearing device according to claim 1 which rotatably supports an arm with a magnetic head.
3. The bearing device according to claim 1 , wherein the flange and the shaft are formed as a one-piece body.
4. A hard disk drive comprising a bearing device according to claim 3 which rotatably supports an arm with a magnetic head.
5. The bearing device according to claim 1 , wherein another flange having a similar structure to the flange and not formed in one piece with the shaft is arranged at another part of the shaft.
6. A hard disk drive comprising a bearing device according to claim 5 which rotatably supports an arm with a magnetic head.
7. A bearing device comprising:
a rolling bearing having an outer ring and an inner ring;
a shaft fixed to the inner ring;
a sleeve fixed to the outer ring;
a flange formed on at least one end part of the shaft, the flange comprising:
a disk part extending from the shaft toward an outside in a radial direction; and
a cylindrical part disposed at an outside of the outer ring and extending from the disk part along a direction of an axis; and
a labyrinth gap that bends in at least two places, the labyrinth gap being formed by:
a first gap formed between the cylindrical part and the sleeve, the first gap including a part perpendicular to the axis and a part parallel to the axis, a width of the part of the first gap perpendicular to the axis being greater than a width of the part of the first gap parallel to the axis;
a second gap faced by an inner circumferential surface of the cylindrical part; and
a third gap formed between the outer ring and the disk part.
8. The bearing device according to claim 7 , wherein the width of the part of the first gap parallel to the axis is not greater than a width of the second gap or a width of the third gap.
9. A hard disk drive comprising a bearing device according to claim 7 which rotatably supports an arm with a magnetic head.
10. The bearing device according to claim 7 , wherein the flange and the shaft are formed as a one-piece body.
11. The bearing device according to claim 7 , wherein another flange having a similar structure to the flange and not formed in one piece with the shaft is arranged at another part of the shaft.
12. A bearing comprising:
a rolling bearing having an outer ring and an inner ring;
a shaft fixed to the inner ring;
a sleeve fixed to the outer ring;
a first flange formed on at least one end part of the shaft, the first flange comprising:
a disk part extending from the shaft toward an outside in a radial direction; and
a cylindrical part disposed radially outside of the outer ring and extending from the disk part along a direction of an axis;
a second flange arranged at another part of the shaft, the second flange having a similar structure to the first flange and being not formed in one piece with the shaft; and
a labyrinth gap that bends in at least two places, the labyrinth gap being formed by:
a first gap formed between the cylindrical part and the sleeve;
a second gap faced by an inner circumferential surface of the cylindrical part; and
a third gap formed between the outer ring and the disk part.
13. The bearing device according to claim 12 , wherein the second flange is fixed to the shaft by adhesive, interference fit, or welding.