JP2000324748A - Outer rotor type brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an outer rotor type brushless motor which can reduce cost by reducing the number of constituent parts. SOLUTION: This motor is equipped with a rotor 4 equipped with a permanent magnet 2 at the inside periphery and is supported by a rotary shaft 3, and a stator 6 which is arranged within the rotor 4 so as to counterpose the permanent magnet 2 and has a rotary shaft 3 pierced via a bearing 5 at the center. A circuit board 11 mounted with a drive circuit for this brushless motor and an attachment plate 13 for attaching this brushless motor are attached to the side of the stator 6. A stator mold part 7, which supports a stator core 8 with the stator 6, is fixed directly to the attachment plate 13. The stator mold part 7 is made to directly support a bearing 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer rotor type brushless motor in which a rotor rotates around an outer periphery of a stator.

[0002]

2. Description of the Related Art FIG. 4 is a vertical sectional view showing the structure of a conventional outer rotor type brushless motor of this kind.

[0003] This outer rotor type brushless motor has a permanent magnet 2 provided on the inner circumference of a cylindrical portion of a cap-shaped rotor yoke 1, and a rotor 4 supported by a rotating shaft 3 and rotating, and opposed to the permanent magnet 2. And a stator 6 in which the rotating shaft 3 passes through a bearing 5 at the center. The stator 6 has a structure in which a stator core 8 is supported by a stator mold portion 7, and a stator coil 9 is wound around a pole portion of the stator core 8. The stator 6 is fixed to the outer periphery of a cylindrical boss 10, and the rotating shaft 3 is rotatably supported through the inner periphery of the boss 10 via a bearing 5. A circuit board 11 on which a drive circuit for the brushless motor is mounted is supported by a stator mold section 7 via a spacer 12. Boss 1
At 0, a mounting plate 13 for mounting the brushless motor to a mounting partner is mounted.

[0004]

In such an outer rotor type brushless motor, cost reduction is strictly required.
There is a need to reduce components.

An object of the present invention is to provide an outer rotor type brushless motor capable of reducing costs by reducing the number of components.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a rotor having a permanent magnet on its inner periphery and rotating while being supported by a rotating shaft;
A stator disposed in the rotor so as to face the permanent magnet and having a rotating shaft penetrating through a bearing at the center, and a circuit board on which a drive circuit of the brushless motor is mounted on the stator side; An improvement is made to an outer rotor type brushless motor on which a mounting plate for mounting the brushless motor is mounted.

[0007] In the outer rotor type brushless motor according to the present invention, the stator mold portion supporting the stator core by the stator is directly fixed to the mounting plate. A bearing is directly supported on the stator mold portion.

[0008] In the outer rotor type brushless motor having such a structure, the boss is omitted and the stator mold portion replaces the boss, so that the number of components can be reduced and the cost can be reduced.

According to the present invention, the stator mold portion has a tubular portion at the center thereof, an end of the tubular portion is directly fixed to the mounting plate, and a bearing is supported on the inner periphery of the tubular portion. Is preferred. With such a structure,
The boss can be sufficiently replaced with the stator mold portion.

[0010]

FIG. 1 is a longitudinal sectional view of a left half of a first example of an outer rotor type brushless motor according to the present invention. Parts corresponding to those in FIG. 4 described above are denoted by the same reference numerals.

In the outer rotor type brushless motor of this embodiment, a stator mold part 7 supporting a stator core 8 by a stator 6 has a cylindrical part 7a at the center thereof. A positioning projection 7b is integrally provided at an end of the cylindrical portion 7a, and the positioning projection 7b is fitted into a hole of the mounting plate 13 so that the stator 6 is directly fixed to the mounting plate 12. This stator mold part 7
The bearing 5 is directly supported in the cylindrical portion 7a, and the rotating shaft 3 is rotatably supported through. A circuit board 11 on which a drive circuit for the brushless motor is mounted is supported by a stator mold section 7 via a spacer 12.
The stator mold portion 7 is formed of, for example, polybutylene terephthalate resin (PBT), polyphenylene sulfide resin (PPS), or the like.

In the outer rotor type brushless motor having such a structure, the boss 10 shown in FIG. 4 is omitted and the stator mold portion 7 is used instead of the boss 10, so that the number of components can be reduced and the cost can be reduced. . In particular, when the stator mold portion 7 has a cylindrical portion 7a at the center thereof, the end of the cylindrical portion 7a is directly fixed to the mounting plate 13, and the bearing 5 is supported on the inner periphery of the cylindrical portion 7a. The boss 11 can be sufficiently replaced with the stator mold portion 7.

FIG. 2 is a vertical sectional view of a left half of a second embodiment of the outer rotor type brushless motor according to the present invention. Note that parts corresponding to those in FIG. 1 described above are denoted by the same reference numerals.

In the outer rotor type brushless motor of this embodiment, the circuit board 11 is fixed to the outer periphery of the cylindrical portion 7a of the stator mold portion 7. Other configurations are the same as those of the above-described first example shown in FIG.

With such a configuration, the same effect as in the first example can be obtained.

FIG. 3 is a vertical sectional view of a left half of a third embodiment of the outer rotor type brushless motor according to the present invention. Note that parts corresponding to those in FIG. 1 described above are denoted by the same reference numerals.

In the outer rotor type brushless motor of the present embodiment, a sintered oil-impregnated bearing 5 'is supported on the inner periphery of the cylindrical portion 7a of the stator mold portion 7. Other configurations are
This is the same as the first example shown in FIG.

With such a configuration, the same effect as in the first example can be obtained.

[0019]

In the outer rotor type brushless motor according to the present invention, the stator mold portion supporting the stator core by the stator is directly fixed to the mounting plate, and the bearing is directly supported by the stator mold portion. The boss is omitted and the stator mold part replaces the boss instead, so that the number of components can be reduced and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a left half vertical section view showing a first example of an embodiment of an outer rotor type brushless motor according to the present invention.

FIG. 2 is a left half vertical sectional end view showing a second example of the embodiment of the outer rotor type brushless motor according to the present invention.

FIG. 3 is a left half vertical sectional end view showing a third example of the embodiment of the outer rotor type brushless motor according to the present invention.

FIG. 4 is a longitudinal sectional view showing a conventional outer rotor type brushless motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor yoke 2 Permanent magnet 3 Rotating shaft 4 Rotor 5 Bearing 5 'Sintered oil-impregnated bearing 6 Stator 7 Stator mold part 7a Tubular part 7b Positioning protrusion 8 Stator core 9 Stator coil 10 Boss 11 Circuit board 12 Spacer 13 Mounting plate

Claims (2)

[Claims] A rotor provided with a permanent magnet on an inner periphery thereof and supported by a rotating shaft to rotate; and a rotating shaft disposed in the rotor so as to face the permanent magnet and having a center at a center through a bearing. An outer rotor type brushless motor in which a circuit board on which a drive circuit of the brushless motor is mounted and a mounting plate for mounting the brushless motor are mounted on the stator side. An outer rotor type brushless motor, wherein a stator mold part supporting a stator core by a stator is directly fixed to the mounting plate, and the bearing is directly supported by the stator mold part. 2. The stator mold portion has a tubular portion at its center, an end of the tubular portion is directly fixed to the mounting plate, and the bearing is supported on an inner periphery of the tubular portion. The outer rotor type brushless motor according to claim 1, wherein: