Automatic balancing apparatus, rotating apparatus, disc drive apparatus, and balancer

Abstract

An automatic balancing apparatus is disclosed. The automatic balancing apparatus includes a plurality of magnets, magnetic fluid, and a rotatable housing. The magnets function as balancers. The rotatable housing has a moving path disposed along a peripheral direction of the rotation. Each of the magnets is moved through the moving path. The rotatable housing accommodates the magnets and the magnetic fluid.

Description

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view showing an automatic balancing apparatus according to an embodiment of the present invention;

FIG. 2 is a sectional view showing the automatic balancing apparatus shown in FIG. 1;

FIG. 3 is a sectional view taken along line A-A of FIG. 2;

FIG. 4 is a sectional view showing a disc drive apparatus in which the automatic balancing apparatus is mounted;

FIG. 5A and FIG. 5B are schematic diagrams showing a sequence of operation states of the automatic balancing apparatus;

FIG. 6 is a perspective view showing a magnet formed in a rectangular parallelepiped shape according to another embodiment of the present invention;

FIG. 7 is a perspective view showing a magnet formed in a circularly cylindrical shape according to another embodiment of the present invention;

FIG. 8 is a perspective view showing a magnet formed in a tubular shape having a through-hole according to another embodiment of the present invention;

FIG. 9 is a perspective view showing an automatic balancing apparatus according to another embodiment of the present invention;

FIG. 10 is a sectional view showing the automatic balancing apparatus shown in FIG. 9;

FIG. 11 is a sectional view taken along line B-B of FIG. 10;

FIG. 12 is a sectional view showing an automatic balancing apparatus of which magnets according to another embodiment are disposed in a housing shown in FIG. 9 to FIG. 11;

FIG. 13 is a sectional view showing an automatic balancing apparatus of which magnets according to another embodiment are disposed in the housing shown in FIG. 9 to FIG. 11;

FIG. 14A, FIG. 14B, and FIG. 14C are perspective views showing magnets having a plurality of pairs of magnetic poles according to another embodiment of the present invention;

FIG. 15 is a perspective view showing a magnet having a plurality of pairs of magnetic poles like FIG. 14A, FIG. 14B, and FIG. 14C;

FIG. 16 is a sectional view showing an automatic balancing apparatus having magnets (balancers) with back yokes disposed on the inner periphery side;

FIG. 17 is a perspective view showing the balancer shown in FIG. 16;

FIG. 18 is a perspective view showing a balancer having an magnet exposed on the outer peripheral surface;

FIG. 19 is a sectional view showing an automatic balancing apparatus having the balancers shown in FIG. 18;

FIG. 20 is a sectional view taken along line C-C of FIG. 19;

FIG. 21 is a perspective view showing a balancer having a magnetic gap on each outer periphery side;

FIG. 22 is a sectional view showing a part of an automatic balancing apparatus having the balancer shown in FIG. 21;

FIG. 23 is a sectional view showing a balancer of which a back yoke is mounted on a magnet formed in a rectangular parallelepiped shape;

FIG. 24 is a sectional view showing a balancer having a yoke with magnetic gaps and a magnet formed in a rectangular parallelepiped shape;

FIG. 25 is a sectional view showing a balancer having a yoke with for example three magnets;

FIG. 26A and FIG. 26B are a perspective view and a sectional view showing a balancer having a magnet coated with a resin member;

FIG. 27A, FIG. 27B, and FIG. 27C are perspective views showing other magnets according to another embodiment of the present invention;

FIG. 28 is a sectional view showing a part of an automatic balancing apparatus of which the magnet shown in FIG. 27A is disposed in a moving path of a housing;

FIG. 29 is a sectional view showing a housing having a moving path whose outer peripheral wall surface is curved;

FIG. 30A and FIG. 30B are sectional view showing a moving path formed in a housing according to another embodiment of the present invention;

FIG. 31 is a sectional view showing a modification of a space formed between the magnet shown in FIG. 30 and the outer peripheral wall surface;

FIG. 32 is a sectional view showing another modification of a space formed between the magnet shown in FIG. 30 and the outer peripheral wall surface;

FIG. 33 is a sectional view showing an automatic balancing apparatus having a moving path in which an air path is formed;

FIG. 34 is a sectional view taken along line D-D of FIG. 33;

FIG. 35 is a sectional view showing a part of an automatic balancing apparatus in which a magnetic fluid film is formed on the entire periphery of an outer peripheral wall surface;

FIG. 36 is a perspective view showing a magnet on which a plurality of grooves are formed;

FIG. 37 is a sectional view showing the state that the magnet shown in FIG. 36 is disposed in a housing;

FIG. 38 is a perspective view showing a magnet having a plurality of holes formed on the front surface;

FIG. 39 is a schematic diagram showing a magnet having triangular depressed and raised grooves formed on the front surface;

FIG. 40 is a sectional view showing a housing having grooves formed in a moving path;

FIG. 41 is a sectional view showing a magnet having a tapered or curved surface formed on the outer periphery;

FIG. 42 is a sectional view showing an automatic balancing apparatus having an attenuation member;

FIG. 43 is a perspective view showing the attenuation member shown in FIG. 42;

FIG. 44 is a sectional view showing an automatic balancing apparatus having an attenuation member according to another embodiment of the present invention;

FIG. 45 is a perspective view showing the A attenuation member shown in FIG. 44;

FIG. 46 is a sectional view showing a disc drive apparatus according to another embodiment of the present invention;

FIG. 47 is a sectional view showing a disc drive apparatus according to another embodiment of the present invention; and

FIG. 48 is a sectional view showing an automatic balancing apparatus having four magnets.

Claims

1. An automatic balancing apparatus, comprising: a plurality of magnets which function as balancers;magnetic fluid; anda rotatable housing which has a moving path disposed along a circumferential direction of the rotation, the plurality of magnets being moved through the moving path, and which accommodates the individual magnets and the magnetic fluid.

2. The automatic balancing apparatus as set forth in claim 1, wherein each of the magnets is formed in an arc block shape along the peripheral direction.

3. The automatic balancing apparatus as set forth in claim 1, wherein each of the magnets is formed in a columnar shape.

4. The automatic balancing apparatus as set forth in claim 1, wherein the moving path allows each of the magnets to be moved while a posture of each of the magnets is maintained.

5. The automatic balancing apparatus as set forth in claim 4, wherein each of the magnets has a first width on a plane nearly perpendicular to a rotational axis of the rotation and in a direction perpendicular to a radial direction of the rotation, andwherein the moving path has a second width smaller than the first width in the radial direction.

6. The automatic balancing apparatus as set forth in claim 5, wherein each of the magnets is magnetized such that they repel each other along the moving path.

7. The automatic balancing apparatus as set forth in claim 6, wherein each of the magnets is magnetized with the same polarity on the same side in the direction of the rotational axis of the rotation.

8. The automatic balancing apparatus as set forth in claim 6, wherein each of the magnets is magnetized such that the same polarity faces each other in the peripheral direction.

9. The automatic balancing apparatus as set forth in claim 6, wherein each of the magnets is magnetized such that their polarities are symmetrical with respect to the center of the rotation in the radial direction of the rotation.

10. The automatic balancing apparatus as set forth in claim 1, wherein each of the magnets has a plurality of pairs of magnetic poles.

11. The automatic balancing apparatus as set forth in claim 10, wherein each of the magnets has a plurality of pairs of magnetic poles in the peripheral direction of the rotation.

12. The automatic balancing apparatus as set forth in claim 1, further comprising: a yoke mounted on the magnet.

13. The automatic balancing apparatus as set forth in claim 12, wherein the yoke is formed such that magnetic flux of the magnet concentrates on the outer periphery side of the rotation.

14. The automatic balancing apparatus as set forth in claim 13, wherein the magnet has an inner periphery surface facing the inner periphery side of the rotation, and wherein the yoke covers the inner periphery surface.

15. The automatic balancing apparatus as set forth in claim 13, wherein the magnet has an outer peripheral surface that faces the outer periphery side of the rotation, andwherein the yoke covers the magnet such that the outer peripheral surface of the magnet is exposed.

16. The automatic balancing-apparatus as set forth in claim 13, wherein the yoke has a magnetic gap on the outer periphery side of the rotation.

17. The automatic balancing apparatus as set forth in claim 1, further comprising: a resin member which coats the magnet.

18. The automatic balancing apparatus as set forth in claim 1, wherein each of the magnets has an outer peripheral portion having a curved surface, andwherein the moving path has an outer peripheral wall surface having a curved path surface.

19. The automatic balancing apparatus as set forth in claim 1, wherein each of the magnets has a taper surface formed on the outer periphery side of the rotation, the width in the axial direction of the rotation gradually decreasing outwardly on the outer periphery side, andwherein the moving path has a taper wall surface formed on the outer peripheral surface of the rotation, the width in the axial direction of the rotation gradually decreasing outwardly on the outer periphery side of the rotation.

20. The automatic balancing apparatus as set forth in claim 1, wherein the moving path has an air path which extends from the inner periphery side of the rotation to the outer periphery side.

21. The automatic balancing apparatus as set forth in claim 1, wherein the moving path has an outer peripheral wall surface on the outer periphery side of the rotation, andwherein the magnetic fluid is supplied for an amount that allows centrifugal force of the rotation to cause the magnetic fluid to flow to the outer periphery side of the rotation and a film of the magnetic fluid to be formed on the entire periphery of the outer peripheral wall surface.

22. The automatic balancing apparatus as set forth in claim 1, wherein the moving path has a sticking prevention section which prevents each of the magnets from sticking to a path surface of the moving path.

23. The automatic balancing apparatus as set forth in claim 22, wherein the sticking prevention section is made of grooves or depressed and raised portions formed on the path surface of the moving path.

24. The automatic balancing apparatus as set forth in claim 22, wherein the path surface of the moving path is formed with predetermined surface roughness.

25. The automatic balancing apparatus as set forth in claim 1, further comprising: an attenuation member which attenuates moving force of each of the magnet.

26. The automatic balancing apparatus as set forth in claim 25, wherein the attenuation member is a member which generates an eddy current as each of the magnets is moved.

27. The automatic balancing apparatus as set forth in claim 26, wherein the attenuation member is made of a non-magnetic substance.

28. The automatic balancing apparatus as set forth in claim 1, wherein the housing is a member which generates an eddy current as each of the magnets is moved.

29. A rotating apparatus, comprising: a plurality of magnets which function as balancers;magnetic fluid;a housing which accommodates the plurality of magnets and the magnetic fluid; anda drive mechanism which rotates the housing.

30. The rotating apparatus as set forth in claim 29, wherein the drive mechanism is aligned with the housing in the axial direction of the rotation and generates a leaked magnetic field in the axial direction, andwherein the magnets are magnetized in the radial direction of the rotation.

31. The rotating apparatus as set forth in claim 29, wherein the drive mechanism is aligned with the housing in the radial direction of the rotation and generates a leaked magnetic field in the radial direction, andwherein the magnets are magnetized in the radial direction.

32. A disc drive apparatus, comprising: a holding section which holds a disc on which a signal is recordable;a plurality of magnets which function as balancers;magnetic fluid;a housing which accommodates the plurality of magnets and the magnetic fluid; anda drive mechanism which rotates the holding section and the housing together.

33. A balancer used for an automatic balancing apparatus which balances the rotation of an object, comprising: a magnet; anda yoke which is mounted on the magnet.