JP2985681B2 - Brushless motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor applied to a spindle motor for driving a CD-ROM.

[0002]

2. Description of the Related Art In a brushless motor used in a conventional disk drive spindle motor, as shown in FIGS. 6 and 7, a drive magnet 102 is fixed to an outer peripheral portion of a rotor 101 and is opposed to the drive magnet 102. The armature core 104 is disposed so that each of the three teeth 103 is perpendicular to the tangent to the circumference of the rotor 101, and the armature coil 105 wound around each of the teeth 103.
Is fixed to the base substrate 106 to fix the stator 107 to the base substrate 106 (for example, see Japanese Utility Model Laid-Open No. 5-86151). In addition,
Reference numeral 108 denotes a moving space for the head assembly 109.

[0003]

With respect to the spindle motor for driving a disk, miniaturization and high-speed operation are progressing due to a demand for miniaturization and high capacity of a device to be incorporated. However, in order to cope with an increase in capacity, it is necessary to increase the rotation speed and reduce vibration noise. For example, CD-ROM
The driving spindle motor is required to rotate at a high speed of about 1000 to 2400 rpm, which is about four times as high as the so-called music CD rotation speed. In the CD-ROM drive spindle motor, it is necessary to change the rotational angular velocity in inverse proportion to the radius of the data track in order to control the linear velocity of the CD to be constant. Therefore, in order to shorten the data access time by performing a CLV (constant linear velocity) operation, the rotation speed must be changed in a short time, and the maximum current is frequently supplied to the armature coil 105. The amount of heat generated by the coil 105 increases.

However, the conventional brushless motor has a problem that heat radiation characteristics are poor because one surface of the armature coil 105 is in contact with the base substrate 106. In addition, it is difficult to wind the armature coil 105 around each of the teeth 103 formed at right angles to the tangent of the circumference of the rotor 101 until the armature coil 105 is adjacent to the other armature coil 105. However, there is a problem that the space efficiency is deteriorated. Also, teeth 103
Since the tip 103a has a T-shape, the armature coil 105 must be wound for each individual tooth, and the production efficiency and the yield of the material of the stator 107 are poor. Further, a magnetic sensor (for example, a Hall element) constituting a position detecting means for detecting the rotational position of the rotor 101 is affected by the drive current of the armature coil 105 to increase vibration and noise. There is a problem that cogging increases depending on the mounting position of the 104, and vibration and noise increase with an increase in speed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. It is an object of the present invention to provide a brushless motor having improved heat radiation characteristics, vibration and noise characteristics and small cogging. It is intended to provide.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a rotor having a driving magnet fixed to an outer peripheral portion, a position detecting means for detecting the position of the rotor, and an output of the position detecting means. A driving means for controlling a driving current to flow through the armature coil in accordance with the armature coil; a stator having the armature coil formed with three teeth in a space other than the moving space portion of the head structure; and a stator having the armature coil; In a brushless motor including a shield yoke formed so as to surround the rotor in a space other than the space where the armature core is arranged, a center tooth of the armature core is arranged in a direction perpendicular to a tangent to a circumference of the rotor, and Are formed in a substantially E-shape by extending the outer peripheral surface of the driving magnet in parallel with and at the same width as the central tooth, and the armature coils are respectively formed. The wound in the bottle is obtained fitted to the teeth.

It is preferable that the position detecting means is disposed at an electrical angle of 120 degrees or more from the armature core.

The bobbin around which the armature coil is wound and the teeth may be provided with a detachment preventing mechanism for preventing the bobbin from coming off.

It is preferable to provide a mounting base made of a metal material for mounting the armature core.

[0010] A mounting position adjusting means for adjusting the mounting position of the armature core may be provided.

[0011]

The heat radiation characteristics, vibration and noise characteristics of heat generated from the armature coil are improved, and cogging is reduced. Further, the manufacture of the armature coil is facilitated, and the armature coil is easily assembled to the teeth.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a schematic plan view of a brushless motor according to the present invention, FIG. 2 is a schematic side view of the same, FIG. 3 is an exploded perspective view showing an assembling relationship between an armature coil, an armature core and a mounting base, and FIG. FIG. 5 is a cross-sectional view of the bobbin, and FIG. 5 is an explanatory diagram showing a positional relationship among the teeth, the driving magnet, and the Hall element.

As shown in FIGS. 1 and 2, a brushless motor 1 is a quadruple speed brushless motor for a CD-ROM, and a rotor having a driving magnet 2 magnetized with 16 magnetic poles on the outer periphery. 3, a Hall element 4 serving as a position detecting means for detecting the rotational position of the rotor 3, and a Hall element 4
Drive means (not shown) for controlling the drive current flowing through the armature coil 5 in accordance with the output of the armature coil 5, a stator 7 comprising the armature core 6 and the armature coil 5, and the rotor 3 Yoke 8 formed so as to surround
It is provided with.

The rotor 3 is integrally connected to a rotatable shaft 10 having a CD turntable (not shown) attached to the tip.

The stator 7 has three teeth 11, 1
Armature core 6 having resin 13 and bobbin 14 made of resin
Armature coil 5 wound around each tooth 11,
A bobbin 14 is inserted into the holes 12 and 13. The armature core 6 is provided in a space other than the moving space portion S of a head structure (not shown) that moves integrally with a head that reads recorded contents of a CD-ROM, which is a disk-shaped recording medium.

The armature core 6 has a central tooth 11 disposed in a direction perpendicular to a tangent to the circumference of the rotor 3 and other teeth 12, 13 parallel to the central tooth 11 and having the same width. By making it W and extending on the outer peripheral surface of the driving magnet 2, the whole is formed in a substantially E-shape. Thus, by forming the armature core 6 in this manner, a material can be obtained in which a plurality of armature cores 6 face each other at the time of manufacturing, so that the yield is improved.

Since the armature coil 5 is wound around each of the teeth 11, 12, 13 via the bobbin 14, the teeth 1
The armature coil 5 can be wound alone on the bobbin 14 instead of directly winding the armature coil 5 on 1, 12, and 13. Therefore, the number of turns must be increased until the armature coil 5 contacts the adjacent armature coil 5. This improves the space efficiency of the armature coil and improves the workability of assembly.

As shown in FIGS. 3 and 4, one end surface of the cylindrical bobbin 14 has an inwardly projecting portion 14a.
The teeth 11, 12 and 13 are formed with concave portions 11 a, 12 a and 13 a corresponding to the convex portions 14 a. Therefore,
The bobbin 14 around which the armature coil 5 is wound is the tooth 11,
When the projections 14a are inserted into the projections 12 and 13, the projections 14a are elastically deformed and engaged with the recesses 11a, 12a and 13a, and the projections 14a and the recesses 11a, 12a and 13a constitute a slip-out prevention mechanism.

The stator 7 is fixed by attaching the armature core 6 to a base substrate 17 via a mount 16 made of a metal material. The armature core 6 and the mounting base 16
As shown in FIG. 3, each corresponding mounting hole 6a, 16a
Are fixed to the base substrate 17 by inserting the screws 18 into the mounting holes 6 a and 16 a and screwing the screws 18 into the screw holes of the base substrate 17. Therefore, the armature coil 5
Is fixed in a floating state without contacting the base substrate 17.

The mounting hole 6a of the armature core 6 is made larger with respect to the shaft diameter of the screw 18, and the gap between the armature core 6 and the rotor 3 is adjusted to a position where cogging is reduced so that the armature core 6 is screwed. Can be fixed with Therefore, the mounting hole 6a and the screw 18
This constitutes a mounting position adjusting means capable of adjusting the mounting position of the armature core 6.

The three teeth 11, 12, 13 are shown in FIG.
As shown in the figure, the other teeth 12 and 13 are located at 60 degrees left and right with respect to the center of the rotor 3 with respect to the center tooth 11 opposed to the driving magnet 2 via a predetermined gap.
Is arranged so that the tip of the drive magnet 2 faces the drive magnet 2 via a predetermined gap.

As shown in FIG. 5, the three Hall elements 4 are arranged at 105 degrees, 157.5 degrees on the base substrate 17 with respect to the center of the teeth 11 as viewed from the center of the rotor 3.
210 degree position, or -105 degree, -157.5 degree,-
It is arranged at a position of 210 degrees.

In this embodiment, the Hall element 4 is used as the position detecting means for detecting the rotational position of the rotor 3. However, as another method, for example, the rotor 3 is controlled in accordance with an induced voltage generated in the armature coil 5. The unique effect of the present invention can be obtained even if the position detection signal is generated.

The shield yoke 8 is used to drive the magnet 2
Is provided to prevent the leakage magnetic flux from affecting the operation of the head, and is arranged so as to surround the rotor 3 in a space other than the space where the armature core 6 is arranged as described above.

In the brushless motor 1 configured as described above, a position signal for detecting the rotational position of the rotor 3 generated from the three Hall elements 4 is inputted to the driving means, and the driving current is supplied to the armature by the driving means. The magnetic field is generated by being supplied to the coil 5 and the generated magnetic field and the driving magnet 2
Of the rotor 3 due to the interaction with the magnetic poles
And the rotor 3 rotates at a desired angular velocity.

[0026]

As described above, according to the present invention, the armature coils are wound around the bobbins, and then the bobbins are inserted into the teeth formed in a substantially E-shape. It is possible to increase the number of turns until they come into contact with each other, and the space efficiency of the armature coil is improved. In addition, since the armature coil is wound around the bobbin alone, the workability of the winding operation is improved.

The position detecting means is an electric angle of 12 with the armature core.
Since they are arranged at a distance of 0 degrees or more, vibration and noise are reduced.

Since the mechanism for preventing the bobbin from coming off is provided, the bobbin is securely fixed to the teeth.

Further, since the mounting base for mounting the armature core is provided and the mounting base is made of a metal material, the heat radiation characteristic of the heat generated from the armature coil is improved.

Since the means for adjusting the mounting position of the armature core is provided, cogging can be reduced by adjusting the gap with the rotor.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a brushless motor according to the present invention.

FIG. 2 is a schematic side view of a brushless motor according to the present invention.

FIG. 3 is an exploded perspective view showing an assembling relationship between an armature coil, an armature core, and a mounting base.

FIG. 4 is a partially enlarged cross-sectional view showing a mounted state of a bobbin.

FIG. 5 is an explanatory diagram showing a positional relationship among a tooth, a driving magnet, and a Hall element.

FIG. 6 is a schematic plan view of a conventional brushless motor.

FIG. 7 is a schematic side view of a conventional brushless motor.

[Description of References] 1 ... brushless motor, 2 ... driving magnet, 3 ... rotor, 4 ... hall element (position detecting means), 5 ... armature coil, 6 ... armature core, 6a ... mounting hole, 7 ... stator ,
8 ... Shield yoke, 10 ... Shaft, 11, 12, 1
3 ... teeth, 11a, 12a, 13a ... recesses, 14 ...
Bobbin, 14a: convex portion, 16: mounting base, 16a: mounting hole, 17: base substrate, 18: screw.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02K 29/00 H02K 21/00

Claims (5)

(57) [Claims] A rotor having a driving magnet fixed to an outer peripheral portion thereof; a position detecting means for detecting a position of the rotor;
A drive unit for controlling a drive current flowing through the armature coil in accordance with the output of the position detection unit, an armature core having three teeth formed in a space other than the moving space portion of the head assembly, and the armature coil. A brushless motor comprising a stator provided and a shield yoke formed so as to surround the rotor in a space other than the arrangement space of the armature core,
A central tooth of the armature core is disposed in a direction perpendicular to a tangent of a circumference of the rotor, and other teeth are parallel to the central tooth and have the same width on the outer peripheral surface of the driving magnet. Extended to form a substantially E-shaped shape,
A brushless motor, wherein the armature coils are wound around bobbins, respectively, and fitted into the respective teeth. 2. The brushless motor according to claim 1, wherein said position detecting means is arranged at an electrical angle of 120 degrees or more from said armature core. 3. The brushless motor according to claim 1, wherein said bobbin around which said armature coil is wound and said teeth are provided with a disengagement prevention mechanism for preventing the bobbin from disengaging. 4. The brushless motor according to claim 2, further comprising a metal mounting base for mounting said armature core. 5. The brushless motor according to claim 4, further comprising mounting position adjusting means for adjusting a mounting position of said armature core.