JP2002345202A - Spindle motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid bearing which can exhibit excellent full performance of bearing even under any application environment. SOLUTION: The chassis of a spindle motor 1 is attached with an inner part of a toroidal coil stator 3 via an insulation 11. A drive magnet 5 is mounted on a hub 7 on the upper surface (end surface 4A in the rotating shaft direction) of the toroidal coil stator 4. Since a drive magnet 5 is located in the rotating shaft direction against the toroidal coil stator 4, the rotating torque may be generated and a thrust attraction may also be generated between the drive magnet 5 and the toroidal coil stator 4 and it is possible to apply a stable driving force to a thrust bearing 10. Namely, while the increase of the number of components and complicated assembling work are suppressed and moreover reduction of product cost and reduction in size and weight of product are lowered, a stable driving force may be applied to the thrust bearing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor, for example, a spindle motor for information equipment, audio / video equipment and other equipment, and more particularly to a spindle motor suitable for a disk drive such as a magnetic disk drive and an optical disk drive. .

[0002]

2. Description of the Related Art Conventionally, a slotless brushless motor using an iron core has been widely used as a spindle motor for information equipment, audio / video equipment and other equipment. As a method of generating a thrust suction force acting in the (thrust direction), a method of generating a suction force between an end surface of a radial (radial) magnet 31 and a thrust suction plate 32 (see FIG. 5), a driving magnet In addition, a method of providing the thrust suction magnets 41 and 42 separately (see FIG. 6) is known.

[0003]

However, in the above-mentioned conventional method, dedicated parts for generating a thrust suction force, such as a thrust suction plate and a thrust suction magnet, are required, so that the number of parts is increased and assembly is complicated. Therefore, it is difficult to reduce the product cost and to reduce the size and weight of the apparatus.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and suppresses an increase in the number of parts and a complicated assembling operation to promote a reduction in product cost and a reduction in size and weight of an apparatus. An object of the present invention is to provide a spindle motor that can generate a suction force satisfactorily.

[0005]

According to a first aspect of the present invention, there is provided a spindle motor comprising: a rotating shaft; a toroidal coil type stator disposed in a circumferential direction of the rotating shaft; And a drive magnet disposed so as to at least partially overlap the toroidal coil type stator when projected from the axial direction, wherein a magnetic attraction force between the toroidal coil type stator and the drive magnet is provided. , A rotating force is generated on the rotating shaft, and a thrust force is generated on a thrust bearing that supports the rotating shaft in the axial direction.

[0006] According to this configuration, a rotational torque can be generated by the drive magnet and the coil of the portion of the toroidal coil type stator facing the magnet, and the thrust is attracted between the drive magnet and the toroidal coil type stator. A force can be generated, and a stable thrust can be applied to the thrust bearing. That is, it is not necessary to provide a dedicated component for generating a thrust suction force separately from a conventional component for generating a rotational torque as well as a conventional component for generating a rotary torque. While reducing the number of points and reducing the complexity of assembly work, while promoting reduction of product cost and reduction in size and weight of equipment,
A stable thrust can be applied to the thrust bearing.

In the present invention, since the toroidal coil type stator is used, the air gap is magnetically uniform, so that the occurrence of torque loss due to cogging torque and slot spatial harmonics can be effectively suppressed. .

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described.
Description will be made based on the attached drawings. FIG. 1 is a sectional view of a spindle motor 1 using a toroidal coil type stator according to one embodiment of the present invention.

As shown in FIG. 1, an inner diameter portion of a toroidal coil type stator 3 is attached to a chassis 2 of a spindle motor 1 via an insulating member 11. The drive magnet 5 is located on the upper surface of the toroidal coil type stator 4.
(The end surface 4A in the direction of the rotation axis) is attached to the hub 7.

A rotating shaft 8 functioning as a rotation center shaft is attached to the hub 7, and the rotating shaft 8 is rotatably supported by a radial bearing 9 which can be constituted by a fluid bearing or the like. The radial bearing 9 is provided integrally with the chassis 2 and has a cylindrical end having a closed end.
2 is held. Further, the end 8 of the rotating shaft 8
A is supported by a thrust bearing 10 disposed below the radial bearing 9.

As shown in FIGS. 2 and 3, the toroidal coil type stator 4 has an annular slotless stator core 3A having an insulating layer (film) 3B formed by insulating coating or the like on its outer periphery. And a coil 6 wound around the outer periphery of the stator core 3
And is configured.

According to the spindle motor 1 according to the present embodiment having such a configuration, since the drive magnet 5 is disposed in the thrust direction with respect to the toroidal coil type stator 4, the conductor 6A on the upper surface of the coil is connected to the drive magnet 5. The driving magnet 5 can generate a rotational torque, and can generate a thrust attraction between the driving magnet 5 and the toroidal coil type stator 4, and apply a stable thrust to the thrust bearing 10. It becomes possible.

According to the spindle motor 1 according to the present embodiment, it is necessary to provide a dedicated component for generating a thrust suction force separately from a component for generating a rotational torque as in the prior art. Therefore, an increase in the number of parts can be suppressed, the complexity of the assembling work can be prevented, and further, a reduction in product cost, a reduction in the size and weight of the device, and the like can be promoted.

That is, according to the present embodiment, the thrust bearing 10 can be manufactured while facilitating simplification of the structure and reduction of the product cost.
Can be applied with a stable thrust.

According to this embodiment, since the toroidal coil type stator 4 is used, the air gap is magnetically uniform, so that the cogging torque (the “magnetic attraction force generated between the stator and the rotor” The change of the torque with respect to the rotation angle based on the torque fluctuations (so-called torque unevenness) and the occurrence of torque loss due to slot space harmonics can be effectively suppressed.

FIG. 4 shows an example of a spindle motor in which motor characteristics are improved in a low-speed rotation range.
In addition, the outer peripheral side of the toroidal coil type stator 4
The magnet 50 is also attached (in the radial direction). With such a configuration, the drive magnet 5 and the 6A portion of the coil,
The rotating torque can be generated at two places by the magnet 50 and the 6B portion of the coil, and the driving magnet 5 can generate a thrust attraction between the driving magnet 5 and the stator core 3A. Therefore, it is possible to apply a stable thrust to the thrust bearing 10 while enabling a stable low rotation drive.

In the present embodiment, the stator core 3 and the toroidal coil type stator 4 are shown in FIG.
Although the O-shaped cross section is a quadrangle, it is not limited to this, and may be another polygon or a circle.

The radial bearing 9 according to the present embodiment may be a rolling bearing such as a ball bearing. However, as shown in FIG. 1, a dynamic bearing is provided between the rotating shaft 8 and the radial bearing 9. A lubricant (lubricating oil, grease, or the like) is interposed as a pressurized fluid, and a groove (for example, a herringbone-shaped groove) for generating a dynamic pressure is formed on the outer peripheral surface of the rotating shaft 8. A predetermined dynamic pressure can be generated in the gap between the bearing and the radial bearing 9 so as to achieve good lubrication characteristics while realizing bearing characteristics with less whirling. In addition, a groove (for example, a herringbone-shaped groove) for generating dynamic pressure as shown in FIG. 1 may be formed on the inner peripheral surface (radial bearing surface) side of the radial bearing 9.

[0019]

As described above, according to the spindle motor of the present invention, since the drive magnet is disposed in the direction of the rotation axis with respect to the toroidal coil type stator, it is possible to generate a rotational torque. While you can
A thrust attraction force can be generated between the drive magnet and the toroidal coil type stator, so that a stable thrust can be applied to the thrust bearing. That is, according to the present invention, it is possible not only to generate the rotational torque satisfactorily, but also to provide a dedicated component for generating the thrust suction force separately from the conventional component for generating the rotational torque. Since there is no need to increase the number of parts and to reduce the complexity of assembly work, the reduction in product cost and the reduction in size and weight of the equipment are also promoted, while providing a stable thrust for the thrust bearing. It becomes possible to hang.

In the present invention, since the toroidal coil type stator is used, the air gap is magnetically uniform, so that the occurrence of torque loss due to cogging torque and slot space harmonics can be effectively suppressed. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration example of a spindle motor according to an embodiment of the present invention.

FIG. 2A is a sectional view showing a configuration example of a toroidal coil type stator according to the embodiment. (B)
Fig. 2 is a circuit diagram of the coil.

FIG. 3 is a sectional view showing a configuration example of a stator core according to the embodiment.

FIG. 4 is a cross-sectional view showing another configuration example of the spindle motor according to one embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration example of a conventional spindle motor.

FIG. 6 is a cross-sectional view showing another configuration example of a conventional spindle motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spindle motor 2 Chassis 3 Stator core 4 Toroidal coil type stator 5 Drive magnet 6 Coil 7 Hub 8 Rotary shaft 9 Radial bearing 10 Thrust bearing 11 Insulation member

Claims (1)

[Claims] 1. A rotating shaft, a toroidal coil type stator disposed in a circumferential direction of the rotating shaft, and at least a part of the toroidal coil type stator overlaps when projected from the axial direction of the rotating shaft. And a driving magnet disposed on the rotating shaft, wherein a rotating force is generated on the rotating shaft via a magnetic attraction force between the toroidal coil type stator and the driving magnet, and the rotating shaft is A thrust force for generating a thrust force on a thrust bearing that axially supports the spindle motor.