WO2009110450A1

WO2009110450A1 - Motor

Info

Publication number: WO2009110450A1
Application number: PCT/JP2009/053932
Authority: WO
Inventors: 博之市崎; 忠之金谷; 和洋小野
Original assignee: 日本電産株式会社
Priority date: 2008-03-05
Filing date: 2009-03-03
Publication date: 2009-09-11
Also published as: CN101925956A

Abstract

A motor to which a disc having a mounting hole is removably mounted. The motor has a rotating body rotating about the center axis of the motor, a bearing mechanism for rotatably supporting the rotating body, and a stationary body for holding the bearing mechanism. The rotating body includes a hub and an annular attracting magnet. The hub rotates about the center axis and has a center circular tube section radially opposed to the inner surface of the mounting hole, a lid radially extending from the center circular tube section, and a circular tube section extending axially downward from the outer peripheral edge of the lid. The attracting magnet magnetically attracts the disc, is provided to a portion located radially outward from the center circular tube section so as to be separated from the outer surface of the center circular tube section, and is directly or indirectly secured to the lid. A mounting section for allowing the disc to be placed thereon is provided to that surface of the attracting magnet which faces the lower surface of the disc.

Description

motor

The present invention relates to a motor capable of attaching and detaching a disk. In particular, the present invention relates to a small motor mounted on a portable device.

For example, in a disk drive device mounted on a portable device, a motor that does not include a clamp member and that directly attracts a disk with a suction magnet has been developed. In this motor, a disk is attracted to the motor side by a suction magnet disposed inside the disk mounting surface of the turntable. Examples thereof include JP 2001-84684 A and JP 2006-60890 A.
JP 2001-84684 A JP 2006-60890 A

In the structure disclosed in the above two publications, the side surface of the attraction magnet is in contact with the rotor yoke. For this reason, the magnetic force of the attracting magnet leaks to the rotor magnet and the armature.

Also, with the recent miniaturization of portable devices, there is an increasing demand for miniaturization of mounted motors as well as disk drive devices mounted thereon.

However, in the structures disclosed in the above-mentioned two publications, the attracting magnet is arranged inside the turntable. For this reason, when the motor is further reduced in size, it may be difficult to mold the attraction magnet. Further, as the volume of the attracting magnet is reduced, the magnetic force of the attracting magnet may be reduced.

One object of the present invention is to provide a motor in which the adverse effect of the magnetic force from the attraction magnet is reduced in the motor that attracts the disk by the attraction magnet.

Another object of the present invention is to provide a motor that can attract and hold a disk sufficiently magnetically while having a structure that can reduce the size of the motor in a motor that attracts the disk with a suction magnet.

The present invention
A motor capable of detaching a disk having a mounting hole,
A rotating body that rotates around a shaft;
A bearing mechanism for rotatably supporting the rotating body;
A stationary body holding the bearing mechanism;
With
The rotating body is
A central cylindrical portion facing the inner surface of the mounting hole in the radial direction; a lid portion extending in the radial direction from the central cylindrical portion; and a cylindrical portion extending downward in the axial direction from the outer peripheral edge of the lid portion. A hub that rotates around the shaft,
An annular suction magnet for magnetically attracting the disk;
Have
The attraction magnet has a gap between the central cylindrical portion and a radially outer portion of the central cylindrical portion, and is fixed directly or indirectly to the lid portion.
The motor is characterized in that a mounting member for mounting the disk is provided on a surface of the attraction magnet facing the lower surface of the disk.

In the present invention, first, the attraction magnet is fixed with a gap from the outer surface of the central cylindrical portion of the rotating body. Thus, a magnetic circuit is not formed between the attraction magnet and the hub, and leakage of the magnetic force of the attraction magnet to the rotor magnet side or the armature side through the hub can be reduced.

Furthermore, in the present invention, a mounting portion for mounting the disk is provided on the surface of the attraction magnet that faces the lower surface of the disk. For this reason, the part in which the mounting part is provided can also be made into an attraction magnet. Therefore, compared with the conventional structure, the radial dimension of the motor can be reduced while maintaining the volume of the attraction magnet.

Also, compared with the conventional structure, the radial width of the attracting magnet can be designed relatively freely. That is, since the degree of freedom can be expanded when designing the volume of the suction magnet, it is possible to meet various demands in the force of attracting the disk of the suction magnet. In particular, it is possible to easily meet the demand for increasing the force with which the suction magnet attracts the disk so that the disk does not come off due to the external impact of the motor.

Thus, according to the present invention, it is possible to provide a motor in which the adverse effect of the magnetic force from the attraction magnet is reduced.

Further, according to the present invention, it is possible to provide a motor that can attract and hold a disk sufficiently magnetically while having a structure capable of downsizing the motor in a motor that attracts the disk by a suction magnet.

FIG. 1 is a schematic cross-sectional view of a motor 10 according to a preferred embodiment of the present invention cut in the axial direction. FIG. 2 is a schematic plan view of the motor 10 viewed from the upper side in the axial direction. FIG. 3 is an enlarged view showing a part of the motor 10. FIG. 4 is a schematic cross-sectional view of a motor, which is another preferred embodiment of the present invention, cut in the axial direction. FIG. 5 is a schematic cross-sectional view of a motor according to another preferred embodiment of the present invention cut in the axial direction. FIG. 6 is a schematic cross-sectional view of a motor, which is another preferred embodiment of the present invention, cut in the axial direction. FIG. 7 is a bottom plan view of the rotor holder used in the embodiment shown in FIG. FIG. 8 is a diagram showing a configuration of the center cone, the rotor holder, and the surroundings thereof before the projecting portion is plastically deformed. (A) is the schematic cross section cut in the axial direction, (b) is the bottom view seen from the arrow B in (a). FIG. 9 is a view showing the configuration of the center cone, the rotor holder and the surroundings after the protruding portion is plastically deformed. (A) is the schematic cross section cut in the axial direction, (b) is the bottom view seen from the arrow C in (a).

Explanation of symbols

10,

10a Motor

20, 50 Rotating body 21, 51

Shaft

22, 57 Rotor magnet 23

Hub

231, 521

Base

2311, 5211

Guide part

2312, 5212 Central cylindrical part 232 Outer cover part (lid part)
233

Cylindrical portions

24 and 55

Suction magnets

25 and 56 Placement member 251 Placement surface 30 Stationary body 40 Bearing mechanism 52 Center cone 5213 Extension portion 5222 Projection portion 53 Rotor holder 531 Lid portion 5311 Recess portion 532 Cylindrical portion 54 Yoke 70 Blade H1 Placement Thickness in the axial direction of the member J1 Central axis T1 Thickness in the axial direction of the outer lid portion of the hub T2 Thickness in the radial direction of the cylindrical portion of the hub T3 Thickness in the axial direction of the yoke T4 Radial direction of the cylindrical portion of the rotor holder Thickness T5 Thickness in the axial direction of the lid of the rotor holder

BEST MODE FOR CARRYING OUT THE INVENTION

<Overall structure of motor>
Below, the whole structure of the motor which is preferable one Embodiment in this invention is demonstrated with reference to FIG. 1 and FIG.
FIG. 1 is a schematic cross-sectional view of a motor 10 according to an embodiment of the present invention, cut along a plane along an axial direction including a central axis J1. FIG. 2 is a schematic plan view of the motor 10 as viewed from above.

The motor 10 includes a rotating body 20, a stationary body 30 having an armature 32, and a bearing mechanism 40. The rotating body 20 rotates around a shaft 21 and has a rotor magnet 22. The stationary body 30 has an armature 32 that faces the rotor magnet 22 via a gap in the radial direction. The bearing mechanism 40 is held by the stationary body 30 and rotatably supports the rotating body 20.

Hereinafter, in order to simplify the description in this specification, for the sake of convenience, the rotating body 20 side is referred to as the axial upper side and the stationary body 30 side is referred to as the axial lower side along the central axis J1. However, the central axis J1 does not necessarily coincide with the direction of gravity.

The rotating body 20 includes a shaft 21, a hub 23, a rotor magnet 22, an annular attracting magnet 24, and a placement portion 25.
The shaft 21 is disposed coaxially with the central axis J1, and a hub 23 is fixed to the upper portion of the shaft 21. A rotor magnet 22 and an attraction magnet 24 are fixed to the hub 23. On the upper surface of the attracting magnet 24, a placement portion 25 for placing a disk (not shown) is provided.

The hub 23 is made of a soft magnetic metal material, and in this embodiment, martensitic stainless steel is used.
The hub 23 includes a substantially cylindrical base portion 231, an annular outer lid portion 232, and a cylindrical portion 233. The substantially cylindrical base 231 has an inner surface for fixing the shaft 21. The outer lid portion 232 has an annular shape extending radially outward from the lower portion of the base portion 231. The cylindrical portion 233 extends from the outer peripheral edge of the outer lid portion 232 along the lower side in the axial direction.

The stationary body 30 includes an armature 32, a housing 31, a mounting plate 33, a circuit board 34, and a cap 35.

The housing 31 has a hollow cylindrical shape that holds the armature 32. The mounting plate 33 is fixed to the housing 31. The circuit board 34 is attached to the upper surface of the attachment plate 33. The cap 35 is attached to the lower side in the axial direction of the attachment plate 33.

The housing 31 has a hollow cylindrical shape having an outer surface that holds the armature 32. The outer surface of the housing 31 includes an armature holding portion 311 that holds the armature 32, and a mounting plate fixing portion 312 that is provided below the armature holding portion 311 in the axial direction and fixes the mounting plate 33. Consists of.

The armature 32 includes an armature core 321 having a core back portion 3211 and a teeth portion 3212, and a coil 322.
The core back portion 3211 has an inner surface that contacts the outer surface of the housing 31. Teeth portion 3212 extends radially outward from core back portion 3211. The coil 322 is formed by winding a conductive wire around the tooth portion 3212 a plurality of times.

In addition, the core back part 3211 is a site | part inside radial direction rather than the broken line along the central axis J1 of the armature 32 in FIG. The teeth part 3212 is a part radially outside the broken line along the central axis J1 of the armature 32 in FIG. A plurality of teeth portions 3212 are provided apart from each other in the circumferential direction. In the present embodiment, six teeth portions 3212 are provided.

Also, the coil 322 is formed by concentrated winding in which one conductive wire is intensively wound around each tooth portion 3212. The coil 322 includes a U phase, a V phase, and a W phase. A neutral point is formed by star-connecting one end of the U phase, the V phase, and the W phase. The other ends of the U-phase, V-phase, and W-phase of the coil 322 and the neutral point are electrically connected to the circuit board 34.

The bearing mechanism 40 includes a substantially hollow cylindrical sleeve 41 and a disc-shaped thrust plate 42. The sleeve 41 is made of an oil-containing sintered material fixed to the inner surface of the housing 31 and holds the shaft 21 so as to be rotatable in the radial direction. The thrust plate 42 is disposed on the upper surface of the mounting plate 33, contacts the lower end surface of the shaft 21, and supports the shaft 21 so as to be rotatable in the axial direction.

<Structure of rotating body 20>
Next, the structure of the rotating body 20 of the motor 10, in particular, the structure on which a disk (not shown) is placed will be described with reference to FIGS. FIG. 3 is an enlarged view of a portion where the disk is placed in the rotating body 20 of FIG. 1, and shows a state in which the placement member is cut off.

The base portion 231 of the hub 23 constituting the rotating body 20 includes a guide portion 2311 and a central cylindrical portion 2312. The guide portion 2311 has a tapered outer surface that guides the disk to the mounting member 25. The central cylindrical portion 2312 is provided on the radially inner side of the attracting magnet 24 and has an outer surface that faces the inner surface (not shown) of the disk mounting hole in the radial direction.
Further, the attracting magnet 24 is fixed to the upper surface of the outer lid portion 232. An annular rotor magnet 22 is fixed to the inner side surface of the cylindrical portion 233.

The attraction magnet 24 has an annular shape and is composed of a rare earth magnet containing neodymium. The rare earth magnet containing neodymium may be manufactured by a sintering method. The attraction magnet 24 is disposed on the upper surface of the outer lid portion 232 of the hub 23 so as to be coaxial with the central axis J1. The inner surface of the attracting magnet 24 is disposed to face the outer surface of the base portion 231 of the hub 23 in the radial direction. A gap is provided in the radial direction between the entire inner surface of the attracting magnet 24 and the entire outer surface of the central cylindrical portion 2312. That is, the attracting magnet 24 and the central cylindrical portion 2312 of the hub 23 are configured not to contact each other.
With this configuration, the magnetic force of the attracting magnet 24 can be reduced from leaking to the rotor magnet 22 side and the armature 32 side.

Further, the attracting magnet 24 can be arranged in alignment with the center of J1 without being affected by the shape of the outer surface of the central cylindrical portion 2312. Therefore, the attracting magnet 24 can be magnetically attracted so that the center of the disk mounting hole coincides with the central axis J1.
Further, chamfered portions may be provided at the upper end portion and the lower end portion of the inner surface and the outer surface of the attracting magnet 24, respectively. In this case, the inner side surface and the outer side surface, the upper surface and the lower surface are respectively connected by an inclined surface over the entire circumference.

A mounting portion for mounting the disk is provided on the upper surface of the suction magnet, that is, the surface facing the lower surface of the disk. Therefore, it is not necessary to separately provide a disk mounting portion, and the outer diameter of the attracting magnet 24 can be increased. That is, the magnetic force of the attracting magnet 24 can be increased, and the force for attracting the disk can be increased.

This structure can maintain the volume of the attracting magnet as compared with the conventional structure especially when the motor 10 is downsized. Such a suction magnet 24 is suitable for reducing the size of the motor 10.

Thus, even if the motor 10 is downsized, the magnetic force of the attracting magnet 24 can be maintained. For this reason, it is possible to prevent the disk from coming off the motor 10 against an impact from the outside of the motor 10. The motor according to the present invention is particularly suitable for mounting on a portable device having a severe demand for impact resistance.

Furthermore, the outer diameter of the suction magnet 24 may be substantially equal to the outer diameter of the cylindrical portion 233 of the hub 23. With such a configuration, the volume of the attracting magnet 24 can be maximized within the limited volume of the motor 10. That is, the magnetic force of the attracting magnet 24 can be increased, and the force for attracting the disk can be increased.

For example, the motor of a disk drive device mounted on a small portable device such as a cellular phone has a small diameter in which the outer diameter of the rotating body 20, that is, the outer diameter of the cylindrical portion 233 of the hub 23 is about 10 mm or less. It is.
Therefore, the attracting magnet becomes small in the conventional arrangement structure. In rare earth magnets that contain neodymium and are sintered, it has been difficult to mold small toroidal magnets.

By the way, conventionally, since the disk mounting portion is provided as a separate member from the magnet, the portion cannot be made a magnet.

However, in the attraction magnet 24 used in the present invention, a disk mounting portion is provided on the upper surface of the attraction magnet. As a result, the outer diameter of the suction magnet 24 can be increased. Specifically, the outer diameter of the attracting magnet 24 can be made approximately the same as the outer diameter of the cylindrical portion 233 of the hub 23. For this reason, the volume of the attracting magnet 24 can be increased. As a result, even a rare earth magnet containing neodymium can be molded relatively easily.

The attraction magnet 24 is magnetized so that one side is a single pole. For example, the upper surface of the attracting magnet 24 facing the lower surface of the disk in the axial direction becomes N pole, and the lower surface facing the upper surface of the outer lid portion 232 of the hub 23 in the axial direction becomes S pole. . On the contrary, the upper surface may be the S pole and the lower surface may be the N pole. Since it is magnetized in this way, the force for attracting the disk downward in the axial direction can be increased. Therefore, even if the motor 10 is downsized, it is possible to suppress a decrease in magnetic force that attracts the disk of the attracting magnet 24 downward in the axial direction.

When the hub 23 is made of a soft magnetic material, it serves as a yoke for each of the rotor magnet 22 and the attraction magnet 24. That is, the hub 23 can reduce leakage of the magnetic forces of the rotor magnet 22 and the attraction magnet 24. The axial thickness T1 of the outer lid portion 232 of the hub 23 is formed to be thicker than the radial thickness T2 of the cylindrical portion 233 of the hub 23 (see FIG. 1). Thereby, it can reduce that the magnetic force to the rotor magnet 22 side and the armature 32 side of the attraction magnet 24 leaks.

Therefore, the magnetic force of the attracting magnet 24 can prevent the magnetic circuit composed of the rotor magnet 22 and the armature 32 from being affected. As a result, it is possible to suppress a reduction in the force with which the attracting magnet 24 attracts the disk and to prevent the magnetic characteristics of the motor 10 from deteriorating.

The mounting member 25 has an annular shape and is formed of a member such as a rubber that prevents the disc from slipping in the circumferential direction. The mounting member 25 is attached to the upper surface of the attracting magnet 24 so as to be coaxial with the central axis J1. The outer surface of the mounting member 25 is disposed so as to be substantially in the same position as the outer peripheral edge of the upper surface of the suction magnet 24. That is, the outer surface of the mounting member 25 is disposed radially inward from the chamfered portion between the outer surface and the upper surface of the attracting magnet 24. Thereby, it can prevent that the outer periphery of the mounting member 25 deform | transforms with the said chamfering part. Therefore, the mounting member 25 can be attached to the upper surface of the suction magnet 24 with high accuracy.

Moreover, with reference to FIG. 3, the process of the mounting member 25 is demonstrated. The mounting member 25 is cut off by the cutter 70 in a state after being mounted on the suction magnet 24 mounted on the hub 23. Specifically, the parting-off process cuts the mounting member 25 by moving the blade 70 in a direction perpendicular to the central axis J1 while the motor 10 is rotated about the central axis J1. Here, the thickness H1 in the axial direction of the mounting member 25 after being cut by the blade 70 may have a portion that is not uniform in the circumferential direction.
By such processing, the disk mounting surface 251 can be made a plane perpendicular to the central axis J1 (see FIG. 1).

In particular, the attracting magnet 24 molded with a rare earth magnet containing neodymium cannot form the flatness of the upper surface of the attracting magnet 24 with high precision, so simply mounting the mounting member 25 on the upper surface of the attracting magnet 24 is not sufficient. The flatness of the upper surface (disk mounting surface) of the mounting member 25 may not be formed with high accuracy. For this reason, even if the disc is placed on the upper surface of the placement member 25, the disc may be shaken and a recording / reproducing error may occur.

However, if the disk mounting surface 251 is formed by cutting after mounting the mounting member 25 on the suction magnet 24, the flatness of the disk mounting surface 251 can be formed with high accuracy. That is, the disk mounting surface 251 can have a plane perpendicular to the central axis J1 without being affected by the flatness of the upper surface of the attracting magnet 24. For this reason, the disk runout can be reduced. As a result, it is possible to provide a highly reliable motor that prevents a disc recording / reproducing error.

As a result, the disc mounting surface 251 may have a portion that is not parallel to the upper surface of the attracting magnet 24 in the circumferential direction.

<Other structure of motor>
A structure relating to a motor 10a which is another preferred embodiment of the present invention will be described with reference to FIG. FIG. 4 is a schematic cross-sectional view taken along the axial direction, showing a structure according to another embodiment of the motor 10a. In the motor 10a, since the stationary body 30 and the bearing mechanism 40 have the same structure and only the structure of the rotating body 50 is different, only the rotating body 50 will be described.

Referring to FIG. 4, rotating body 50 includes a shaft 51, a center cone 52, a rotor holder 53, a yoke 54, a suction magnet 55, a mounting member 56, and a rotor magnet 57. The The shaft 51 is disposed coaxially with the central axis J 1, and the center cone 52 is fixed to the shaft 51. The rotor holder 53 is attached to the center cone 52, and the yoke 54 is attached to the rotor holder 53. The suction magnet 55 is attached to the yoke 54, and the mounting member 56 is attached to the suction magnet 55. The rotor magnet 57 is attached to the rotor holder 53.

The center cone 52 may be formed of a copper-based material having excellent machinability such as brass. The center cone 52 includes a substantially cylindrical base 521 and a fixed portion 522. The fixing portion 522 is fixed to the rotor holder 53 provided at the lower portion of the base portion 521.

The base 521 includes a guide part 5211, a central cylindrical part 5212, and an extension part 5213. The guide portion 5211 has a tapered outer surface that guides the disk to the mounting member 56. The central cylindrical portion 5212 is provided radially inward from the suction magnet 55 and has an outer surface that faces the inner surface (not shown) of the disk mounting hole in the radial direction. The extension portion 5213 is provided on the lower side in the axial direction of the central cylindrical portion 5212 and protrudes radially outward from the central cylindrical portion 5212.

The fixing portion 522 includes a lower surface 5221 and an annular projecting portion 5222. The lower surface 5221 is a surface with which an upper surface of a lid portion 531 of the rotor holder 53 described later comes into contact. The annular projecting portion 5222 projects radially inward from the inner surface of the lid portion 531 of the lower surface 5221 to the lower side in the axial direction.

The rotor holder 53 is formed by pressing a thin steel plate made of soft magnetic material. The rotor holder 53 includes a lid portion 531 and a cylindrical portion 532. The lid 531 extends in the radial direction fixed to the center cone 52. The cylindrical portion 532 extends from the outer peripheral edge of the lid portion 531 to the lower side in the axial direction.

A rotor magnet 57 is attached to the inner surface of the cylindrical portion 532. Further, the inner peripheral edge of the lid portion 531 of the rotor holder 53 and the outer peripheral edge of the protruding portion 5222 of the fixing portion 522 of the center cone 52 are brought into contact with each other. In this state, the vicinity of the tip of the protrusion 5222 is plastically deformed radially outward by pressing or the like. By doing so, the vicinity of the inner peripheral portion of the lid portion 531 of the rotor holder 53 is fixed between the lower surface 5221 of the center cone 52 and the bent protruding portion 5222 in the axial direction. Accordingly, the rotor holder 53 is fixed to the center cone 52 by so-called “caulking”.

A yoke 54 made of a soft magnetic material is attached to the upper surface of the lid 531 by means such as spot welding. In this embodiment, an iron-based material is used. The inner surface of the yoke 54 is fixed by being press-fitted into the outer surface of the extension portion 5213. A suction magnet 55 is attached to the upper surface of the yoke 54. The inner surface of the attracting magnet 55 is disposed in a radial direction with a gap between the outer surface of the central cylindrical portion 5212 and the outer surface of the extension portion 5213. Thus, the yoke 54 can be easily fixed to the center cone 52, and the attracting magnet 55 is coaxial with the central axis J1 without being affected by the shapes of the central cylindrical portion 5212 and the extension portion 5213. Can be arranged.

By disposing the yoke 54 on the lower side in the axial direction of the attraction magnet 55, the magnetic force of the attraction magnet 55 can be prevented from affecting the rotor magnet 57 and the armature 32. In particular, the axial thickness T3 of the yoke 54 is formed to be thicker than the radial thickness T4 of the cylindrical portion 532 of the rotor holder 53. Thereby, it can further reduce that the magnetic force of the attraction magnet 55 affects the rotor magnet 57 and the armature 32. In addition, since the plate thickness of the rotor holder 53 can be reduced, it can be easily pressed. Therefore, the production efficiency of the rotor holder can be improved. Further, by reducing the plate thickness of the rotor holder 53, it is possible to reduce the size of the motor.

Compared with the hub 23 of the motor 10, in the motor 10 a, a part corresponding to the hub 23 is configured by the center cone 52 and the rotor holder 53, thereby increasing the number of parts.
However, in the motor 10 described above, the hub 23 is manufactured by cutting martensitic stainless steel. In comparison with this, in the motor 10a, the center cone 52 is manufactured by cutting a copper-based material, and the rotor holder 53 is manufactured by pressing.

For this reason, each part can be manufactured at low cost. That is, the center cone 52 and the rotor holder 53 of the motor 10a increase in the number of parts and the number of assembly steps, but can be manufactured at a lower cost than the hub 23 of the motor 10. Therefore, it is possible to reduce the price of the motor.

Also, the center cone 52 and the rotor holder 53 are separated. Accordingly, the yoke 54 having an axial thickness is appropriately selected and attached in accordance with the magnetic force of the attraction magnet 55. As a result, the motor 10a is preferable because it can easily cope with the case where the thickness of the suction magnet 55 must be changed.

As mentioned above, although the embodiment of the motor according to the present invention has been described, the present invention is not limited to the above-described embodiment, and various modifications are possible.

In the motor 10a described above, the center cone 52 and the rotor holder 53 are fixed by “caulking”, but the present invention is not limited to this. For example, as shown in FIG. 5, the center cone 62 and the rotor holder 63 are welded by causing a part of the lower surface of the center cone 62 to protrude downward in the axial direction and passing through a through hole 631 provided in the rotor holder 63. It may be fixed by. In the case of FIG. 5, the center cone 62 is preferably a resin material.

Also, the center cone 62 and the rotor holder 63 can be fixed by insert molding. Specifically, after the rotor holder 63 is disposed in the mold, molten resin is injected into the mold to mold the center cone 62, and the center cone 62 and the rotor holder 63 are fastened.

The above-described

attraction magnets

24 and 55 of the

motors

10 and 10a are each magnetized with a single pole, but the present invention is not limited to this. Depending on the specifications of the attracting force of the attracting

magnets

24 and 55, the magnets may be magnetized to have a plurality of magnetic poles in the circumferential direction.

Although the radial position of the outer surface of the attracting magnet 24 is arranged at substantially the same position as the radial position of the outer surface of the cylindrical portion 233 of the hub 23, the present invention is not limited to this. When there is a sufficient space for arranging the motor 10, the radial position of the outer surface of the attracting magnet 24 may be disposed radially outward from the radial position of the outer surface of the cylindrical portion 233.

In the motor 10a, the yoke 54 is press-fitted and fixed to the outer surface of the extension 5213, but is not limited thereto. The yoke 54 may be fixed to the lid portion 531 of the rotor holder 53 by means such as adhesion, or may be a combination of press-fitting and adhesion. Further, after the attracting magnet 55 is fixed to the yoke 54 by means such as adhesion, the yoke 54 may be fixed to the lid portion 531 of the rotor holder 53 by means such as welding or adhesion.

In the motor 10a, the yoke 54 is attached to the upper surface of the rotor holder 53 and the suction magnet 55 is attached. However, the present invention is not limited to this. The suction magnet 55 may be directly attached to the upper surface of the rotor holder 53.

In the motor 10a, the yoke 54 is attached to the upper surface of the lid portion 531 of the rotor holder 53, but the present invention is not limited to this. The yoke 54 may be disposed between the suction magnet 55 and the rotor magnet 57 in the axial direction. For example, as shown in FIG. 6, the yoke 54 may be attached to the lower surface of the lid portion 531 of the rotor holder 53.
By attaching the yoke 54 to the lower surface of the lid portion 531 of the rotor holder 53 in this way, it is possible to prevent the axial thickness or attachment error of the yoke 54 from affecting the axial height of the entire rotating body 50. Can do. FIG. 6 is a schematic cross-sectional view taken along the axial direction, showing another embodiment of the motor of the present invention.

Further, the following configuration is also possible as a configuration for fixing the rotor holder 53 to the center cone 52 by “caulking”. As in the previous embodiment, the protrusion 5222 is plastically deformed to “caulse” and fix the rotor holder 53 to the center cone 52. In this embodiment, the structure of the rotor holder and the state after the protrusion is plastically deformed are as follows. Different from the above embodiment.

Details will be described below with reference to FIGS.
FIG. 7 is a bottom plan view of the rotor holder 53 used in the other embodiment of FIG.
FIG. 8 is a diagram showing a configuration of the center cone 52, the rotor holder 53, and the surroundings thereof before the protruding portion 5222 is plastically deformed. (A) is the schematic cross section cut in the axial direction, (b) is the bottom view seen from the arrow B in (a). (A) is also a cross-sectional view taken along the line AA of (b).
FIG. 9 is a diagram showing a configuration of the center cone 52, the rotor holder 53, and the periphery thereof after the protruding portion 5222 is plastically deformed. (A) is the schematic cross section cut in the axial direction, (b) is the bottom view seen from the arrow C in (a). (A) is also a cross-sectional view taken along the line AA of (b).

First, the rotor holder 53 according to the present embodiment will be described with reference to FIG. As shown in FIG. 7, a concave portion 5311 opened radially inward is partially formed in the inner peripheral edge of the lid portion 531 of the rotor holder 53 along the circumferential direction. In the present embodiment, there are three.

Next, the rotor holder 53 is fixed by “caulking” to the center cone 52. Specifically, the inner peripheral edge of the lid portion 531 of the rotor holder 53 and the outer peripheral edge of the protruding portion 5222 of the fixing portion 522 of the center cone 52 are brought into contact with each other, and the protruding portion 5222 is pressed in that state (the state shown in FIG. 8). The plastic deformation is performed radially outward by equalizing. By doing so, as shown in FIG. 9, the vicinity of the inner peripheral portion of the lid portion 531 of the rotor holder 53 is fixed between the lower surface 5221 of the center cone 52 and the bent protruding portion 5222, and the protrusion Part of the portion 5222 is in a state of being bitten into the recess 5311.

With this configuration, the rotor holder 53 is “caulked” fixed to the center cone 52. Further, the protrusion 5222 bites into the recess 5311 of the rotor holder 53, so that the center cone 52 and the rotor holder 53 can be prevented from shifting in the circumferential direction.

In the above embodiment, three recesses 5311 are formed in the lid portion 531 of the rotor holder 53. However, any number may be used as long as the rotor holder 53 can be prevented from shifting in the circumferential direction with respect to the center cone 52 when the projecting portion 5222 plastically deformed into the recess 5311 is bitten.

Further, for example, as shown in FIG. 6, the axial thickness T3 of the yoke 54 can be formed to be thicker than the axial thickness T5 of the lid portion 531 of the rotor holder 53. By doing in this way, while the magnetic flux leakage of the attraction magnet 55 can be reduced more, the thickness of the rotor holder 54 can be made thin and constant, and a rotor holder can be manufactured easily. Therefore, the motor can be reduced in size.

In the above-described embodiment, the projecting portions 5222 are projected in an annular shape from the fixed portion 522 of the center cone 52 toward the lower side in the axial direction. However, a plurality of projecting portions 5222 are scattered in the circumferential direction instead of the annular shape. The structure which makes the protrusion part protrude may be sufficient.

Claims

A motor capable of detaching a disk having a mounting hole,
A rotating body that rotates around a shaft;
A bearing mechanism for rotatably supporting the rotating body;
A stationary body holding the bearing mechanism;
With
The rotating body is
A central cylindrical portion facing the inner surface of the mounting hole in the radial direction; a lid portion extending in the radial direction from the central cylindrical portion; and a cylindrical portion extending downward in the axial direction from the outer peripheral edge of the lid portion. A hub that rotates around the shaft,
An annular suction magnet for magnetically attracting the disk;
Have
The attraction magnet has a gap between the central cylindrical portion and a radially outer portion of the central cylindrical portion, and is fixed directly or indirectly to the lid portion.
The motor according to claim 1, wherein a mounting portion for mounting the disk is provided on a surface of the attraction magnet facing the lower surface of the disk.
The motor according to claim 1,
The rotating body is
A soft magnetic rotor holder having a central cylindrical portion, a lid portion extending in the radial direction, and a cylindrical portion extending downward in the axial direction from the outer peripheral edge of the lid portion, separately from the central cylindrical portion,
A motor comprising:
The motor according to claim 1 or 2,
A motor in which the outer diameter of the attraction magnet is substantially equal to the outer diameter of the cylindrical portion.
The motor according to any one of claims 1 to 3,
A rotor magnet is attached to the cylindrical portion,
Between the axial direction of the attraction magnet and the rotor magnet, a yoke that is a soft magnetic material is disposed,
The yoke is a motor provided on the lid.
The motor according to claim 4,
The yoke is a motor provided between the upper surface of the lid and the lower surface of the attraction magnet.
The motor according to claim 4,
The yoke is a motor provided on the lower surface of the lid.
The motor according to any one of claims 4 to 6,
The thickness of the yoke in the axial direction is greater than the thickness of the lid of the rotor holder in the axial direction.
The motor according to claim 2,
The central cylindrical portion is formed of a copper-based material,
The rotor holder is a motor formed of a soft magnetic thin plate.
The motor according to claim 2,
The inner peripheral edge of the lid part of the rotor holder and the outer peripheral edge of the protruding part protruding downward from the lower surface of the central cylindrical part,
A motor that fixes the vicinity of the inner peripheral portion of the lid portion of the rotor holder between the lower surface of the central cylindrical portion and the protruding portion by plastically deforming the vicinity of the tip of the protruding portion radially outward. .
The motor according to claim 2,
Forming a recess partially on the inner periphery of the lid of the rotor holder;
Abutting the inner peripheral edge of the lid portion of the rotor holder and the outer peripheral edge of the protruding portion protruding downward from the lower surface of the center cone;
By plastically deforming the vicinity of the tip of the protruding portion radially outward, the inner periphery of the lid portion of the rotor holder is fixed between the lower surface of the center cone and the protruding portion in the axial direction. A motor in which a part of the protruding portion is bitten into the recess.
The motor according to any one of claims 1 to 10,
The mounting member is formed in an annular shape around the central axis,
The axial thickness of the mounting member with respect to the upper surface of the attraction magnet has a portion that is uneven in the circumferential direction so that the upper surface of the mounting member is a plane that is substantially perpendicular to the central axis. motor.
The motor according to any one of claims 1 to 11,
The attraction magnet is a motor that is single-pole magnetized in the axial direction.