JPH06165450A - Spindle motor - Google Patents

Abstract

PURPOSE:To obtain spindle motors which develop a larger torque with a small rotor. CONSTITUTION:A rotor 1 is held on a base 2. A rotor magnet 4 comprising a ring-shaped permanent magnet is provided for the periphery of the rotor 1, thereby forming a magnetic field outside and inside of the rotor 1. An outer stator coil 6 placed outside the rotor magnet 4 is connected in series to an inner stator coil 7 placed inside the rotor magnet 4. The outer stator coil 6 and inner stator coil 7 are mounted on the base 2. Attraction and repulsion forces are generated inside and outside the rotor 1, thereby producing a larger torque with a small rotor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor used in a flexible disk device or the like.

[0002]

2. Description of the Related Art FIGS. 3 and 4 are views showing a conventional spindle motor for a direct drive / flexible disk device, FIG. 3 is a sectional view of the spindle motor, and FIG. 4 is a cross-sectional plan view of an essential part of FIG. . In the figure, (1) is the base
A rotor that is pivotally supported by (2) through a center pin (3) to grip and rotate a flexible disk (not shown), and (4) is an annular permanent magnet, and a rotor peripheral portion of the rotor (1). A rotor magnet that is provided on the base (2) so as to project toward the base (2) and that generates a magnetic field outside the rotor (1); and (5) is a rotor magnet that is provided on the base (2).
A stator coil which is arranged outside (4) and creates a magnetic field generated by the rotor magnet (4) and a magnetic field of attraction and repulsion.

The conventional spindle motor is constructed as described above, and the stator coil (5) is divided into a multiple of 3 and surrounds the rotor (1), where the phase is 120 °.
Alternating three-phase alternating current is flowing, and various magnetic fields are generated around the rotor (1). Further rotor magnet
(4) divides the circumference of the rotor (1) into N poles and S poles uniformly and forms a magnetic field around the rotor (1). These two magnetic fields attract and repel the magnetic field, and since the stator coil (5) is fixed, the rotor (1) rotates in a predetermined direction. Also, since an alternating current is flowing in the stator coil (5), the magnetic field generated by this changes continuously,
Since mutual attraction and repulsion of magnetic fields occur continuously,
(1) rotates.

[0004]

In the conventional spindle motor as described above, the rotor (1) and the stator coil (5) are
There is a problem that the rotation torque of the rotor (1) becomes smaller when the size of the rotor is reduced.

The present invention has been made in order to solve the above problems, and an object of the present invention is to obtain a spindle motor which produces a larger rotating torque even with a small rotor.

[0006]

In a spindle motor according to the present invention, a rotor pivotally supported by a base and an annular permanent magnet are provided on the rotor peripheral portion and are arranged so as to project toward the base side. A rotor magnet that generates a magnetic field inside and outside the rotor, an outer stator coil that is provided on the base and is arranged outside the rotor magnet, and an outer stator coil that is provided on the base and is arranged inside the rotor magnet. An inner stator coil connected in series is provided.

[0007]

In the spindle motor configured as described above, magnetic field attraction and repulsion occur inside and outside the rotor, respectively.

[0008]

1 and 2 are views showing an embodiment of the present invention. FIG. 1 is a sectional view of a spindle motor, and FIG. 2 is a cross-sectional plan view of an essential part of FIG. In the figure, (1) is a rotor that is pivotally supported by a base (2) via a center pin (3) to hold and rotate a flexible disk (not shown), and (4) is an annular permanent magnet. The rotor (1) is provided in the peripheral portion of the rotor and is arranged so as to project toward the base (2).
A rotor magnet that generates a magnetic field inside and outside the rotor (1), (6) is provided on the base (2) and is arranged outside the rotor magnet (4), and attracts the magnetic field generated by the rotor magnet (4). , An outer stator coil that creates a repulsive magnetic field, (7) is provided on the base (2) and a rotor magnet (4)
It is an inner stator coil that is disposed inside the and that creates a magnetic field generated by the rotor magnet (4) and a magnetic field of attraction and repulsion.

In the spindle motor constructed as described above, the outer stator coil (6) and the inner stator coil (7) are divided into multiples of 3, and the rotor magnet (4) is surrounded from both the outside and the inside. , The phase is 1
Three-phase alternating current that is offset by 20 ° flows. Further, the magnetic field of the rotor magnet (4) is generated outside and inside the rotor (1), and the rotor (1) rotates as in the case of the spindle motor of FIGS. 3 and 4. Since the outer stator coil (6) and the inner stator coil (7) are connected in series every three phases, the same current as in the spindle motor of FIGS. 3 and 4 is applied to the outer stator coil (6) and the inner stator coil (7). When the magnetic field is applied to the coil (7), a magnetic field is attracted and repelled on the outer side and the inner side of the rotor (1), so that a larger torque can be obtained. Therefore, even with a small rotor (1), the rotation torque does not decrease, and a spindle motor that produces a larger rotation torque can be realized.

[0010]

As described above, according to the present invention, the rotor pivotally supported by the base and the annular permanent magnet are provided at the peripheral portion of the rotor and are arranged so as to project toward the base side. A rotor magnet for generating a magnetic field on the outside, an outer stator coil provided on the base and arranged outside the rotor magnet, and a rotor magnet provided on the base inside the rotor magnet and connected in series with the outer stator coil An inner stator coil is provided. This causes magnetic field attraction and repulsion inside and outside the rotor, respectively. Therefore, even with a small rotor, the rotation torque does not decrease, and a larger rotation torque can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a spindle motor showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional plan view of main parts of FIG.

FIG. 3 is a cross-sectional view showing a conventional spindle motor.

FIG. 4 is a cross-sectional plan view of the main part of FIG.

[Explanation of symbols]

 1 rotor 2 base 4 rotor magnet 6 outer stator coil 7 inner stator coil

Claims (1)

[Claims] 1. A rotor comprising a rotor pivotally supported by a base, and an annular permanent magnet. The rotor is provided at a peripheral portion of the rotor and is arranged so as to project toward the base side. Magnetic fields are generated inside and outside the rotor. A rotor magnet, an outer stator coil provided on the base outside the rotor magnet, and an outer stator coil provided on the base inside the rotor magnet and connected in series with the outer stator coil. Spindle motor with inner stator coil.