JP2581101Y2 - 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, and more particularly to an improvement in a brushless motor for rotating a recording disk such as a magneto-optical disk.

[0002]

2. Description of the Related Art Conventionally, as a brushless motor of this type, as shown in FIG. 2, a magnetic core 9 is mounted on an outer periphery of a bearing housing 7 in which ball bearings 3 and 5 are fixed in a hollow portion 1.
, A plurality of drive coils 11 are wound around the magnetic core 9, and a plate-shaped metal turntable 17 is supported on a rotating shaft 13 supported by ball bearings 3 and 5 via a support tube 15.
A rotor yoke 19 covering the magnetic core 9 is fixed to the turntable 17, and a drive magnet 21 circumferentially opposed to the magnetic core 9 is fixed inside the rotor yoke 19, and the turntable 17 is fixed to the turntable 17. Has a configuration in which a magnet 23 for attracting, for example, a magneto-optical recording disk (not shown) is fitted.

Reference numeral 25 in FIG. 2 denotes a support flange formed on the outer periphery of the bearing housing 7, and reference numeral 27 denotes a circuit board supported by the support flange 25, and a lead wire from the drive coil 11 is soldered. Attached.

In such a brushless motor, the turntable 17 rotates together with the rotor yoke 19 by switching and driving the plurality of drive coils 11, and the recording disk attracted to the turntable 17 is driven to rotate.

[0005]

However, in the brushless motor having the above-described structure, the separately formed magnet 23 is fitted into the turntable 17, so that the shape of the magnet 23 and the shape of the turntable 17 on which the magnet 23 is fitted are reduced. There was a difficulty that it was difficult to fix unless the dimensions were made accurate.

Further, if the housing of the magnet 23 in the turntable 17 is enlarged, the magnet 23 can be easily fixed to the turntable 17, but a gap is easily generated between the magnet 23 and the turntable 17, so that a good magnetic circuit can be obtained. Is not formed, and the adsorption strength is easily reduced, and improvement has been desired.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional drawback, and it is easy to form a magnet for attracting a rotating body, and does not generate a gap between the magnet and the turntable. An object of the present invention is to provide a brushless motor that does not reduce strength.

[0008]

According to the present invention, a rotor yoke is mounted on a rotating shaft rotatably supported on a stator side, and a driving magnet is fixed to the rotor yoke. Is a brushless motor which has a magnet portion for attracting the magnet and which is attached to the rotating shaft so that a turntable for rotating the rotating body is arranged on the upper surface side of the rotor yoke, and the turntable is formed of a magnetic synthetic resin material. At the same time, the turntable itself is magnetized to form the magnet portion.

In the present invention, the rotor yoke and the turntable can be integrally formed of the same magnetic synthetic resin material, and in addition, the drive magnet can also be integrally formed of the same magnetic synthetic resin material.

[0010]

In the brushless motor having such a configuration, the magnet portion of the rotating body is also used by the turntable itself made of a magnetic synthetic resin material, so that it is not necessary to fix the magnet portion to the turntable separately, There is no gap between the head and the turntable.

In the configuration in which the rotor yoke and the turntable are formed of the same magnetic synthetic resin material, the magnetic path passes through the turntable and the rotor yoke, the magnetic force does not decrease, and the drive magnet is formed of the same magnetic synthetic resin material. In the configuration, the number of components is greatly reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. Note that the same reference numerals are given to portions common to the conventional example.

FIG. 1 is a longitudinal half sectional view showing an embodiment of the brushless motor according to the present invention.

In FIG. 1, a cylindrical bearing housing 7 includes a ball bearing 3 as a bearing in a hollow portion 1 thereof.
5 is coaxially fixed and has a support flange 25 on its outer periphery. A circuit board 27 having a drive circuit and the like (not shown) is supported on the support flange 25.

A magnetic core 9 having a plurality of salient pole teeth 9a is fixed to the outer periphery of the bearing housing 7, and a plurality of drive coils 11 are wound around the salient pole teeth 9a. Soldered to the substrate 27.

A turntable 29 is fixed to the rotary shaft 13 supported by the ball bearings 3 and 5 via a support tube 15 so as to project from the ball bearing 3 side.

The turntable 29 is made of a thermoplastic synthetic resin (magnetic synthetic resin) mixed with a magnetic powder, and has a rotor yoke 31 covering the magnetic core 9 and a tip inside of the magnetic core 9 inside the rotor yoke 31. The drive magnet 33 is formed by integral molding.

Further, the turntable 29 has a dish-shaped main body shape, is magnetized in the axial direction inside the concave portion to form a magnet portion 35, and the drive magnet 33 is magnetized in the radial direction. Is given.

In such a brushless motor, the turntable 29 is rotated by switching and driving the plurality of drive coils 11, and the magnet unit 35 of the turntable 29, for example, a magneto-optical recording disk (not shown).
The metal hub can be rotated by suction.

In such a brushless motor of the present invention, the turntable 29 is formed of a magnetic synthetic resin, and the turntable 29 is magnetized to form the magnet portion 35 itself. It is not necessary to fit the magnet 23 thus set in the turntable 17, and no gap is generated between the magnet part 35 and the turntable 29.

Further, since the rotor yoke 31 and the drive magnet 33 are formed integrally with the turntable 29, the number of components is greatly reduced and the number of assembling steps is reduced.

In the present invention, the rotor yoke 31
In addition to forming the drive magnet 33 integrally with the turntable 29 and forming the turntable 29 and the rotor yoke 31 integrally, it is possible to keep the floppy disk suction strength high.

Furthermore, if the magnet portion 35 is formed on the turntable 29 itself, the magnet portion 35 can be easily formed and no gap is formed between the turntable 29 and the turntable 29 itself.

[0024]

As described above, in the brushless motor of the present invention, the turntable for supporting and rotating the rotating object such as the magneto-optical disk is formed of a magnetic synthetic resin and the magnet portion is formed on the turntable itself. , It is easy to form the magnet part to attract the rotating body,
A gap is not easily formed between the turntable and the turntable, and the adsorption strength is not reduced.

In the configuration in which the rotor yoke and the drive magnet are formed integrally with the turntable, in addition to the effects described above, the number of components is greatly reduced, and the number of assembling steps is reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal half sectional view showing one embodiment of a brushless motor according to the present invention.

FIG. 2 is a longitudinal half sectional view showing a conventional brushless motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow part 3, 5 Bearing (ball bearing) 7 Bearing housing 9 Magnetic core 11 Drive coil 13 Rotating shaft 15 Support tube 17, 29 Turntable 19, 31 Rotor yoke 21, 33 Drive magnet 23 Magnet 25 Support flange 27 Circuit board 35 Magnet part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 19/20

Claims (1)

(57) [Scope of request for utility model registration] 1. A rotating shaft rotatably supported on a stator side, a rotor yoke attached to the rotating shaft, a drive magnet fixed to the rotor yoke, and arranged on an upper surface side of the rotor yoke. A turntable attached to the rotating shaft and having a magnet unit for attracting the rotating body and rotating the rotating body; and a brushless motor comprising: a turntable, a rotor yoke and a driving magnet.
Are integrally formed from the same magnetic synthetic resin material
At the same time, by magnetizing the turntable itself
A brushless motor, wherein the magnet portion is formed .