JPH11313464A - Brushless motor for fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve compactness, light-weight and improvement of rotating characteristics all together of a motor made of steel plates having the advantage of easy treatment as industrial wastes, without deteriorating the characteristics of the motor, and to reduce irregular rotation with increased inertia effected by small dimensions in the axial direction. SOLUTION: This brushless motor of an outer rotor type for a fan is provided with a stator core 4, which comprises core tooth parts wound with stator coils 5, and a rotor which comprises permanent magnetic poles arranged in such a way that it faces the outside circumference of the core tooth parts. In this motor, the ratio of its axial length to a fan diameter and the ratio of its inertia to that of the fan are set to 30% or lower and 10% or lower, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor for a fan used for driving a fan of an air conditioner, a water heater or the like, and more particularly to a brushless motor for a fan in which the thickness of the motor is reduced and the rotation characteristics are improved. About.

[0002]

2. Description of the Related Art For example, a brushless motor used for driving a fan of an air conditioner is often used indoors. Therefore, reduction in size and weight and improvement in rotation characteristics are desired.

[0003] The brushless motors conventionally used are mainly of a mold type in which a main body is formed of resin or the like.

[0004] Recently, a method of treating resins as industrial waste is becoming a problem, and there is a demand for the practical use of a steel plate fan motor that can be easily treated as industrial waste.

[0005]

However, although a steel plate motor can be easily reduced in weight, there are difficulties in downsizing and improvement in rotational characteristics, and this has been the biggest problem in practical use.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a steel plate motor having the advantage of being easily treated as industrial waste without reducing the characteristics of the motor and reducing the size and weight and improving the rotation characteristics, which are the most important issues in practical use. It is to realize both of them at once.

[0007]

In order to achieve the above object, a brushless motor for a fan according to the present invention is changed from an "inner rotor structure system" to an "outer rotor structure system" to improve characteristics as a fan motor. So,
The motor is designed to reduce the axial length and reduce the weight, and to increase the inertia of the motor to reduce uneven rotation.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

The brushless motor according to the present invention shown in FIG. 1 is an outer rotor type thin type. The stator side includes a housing 1, an end bracket 2, a core holder 3, a stator core 4, a stator coil 5, and the like. The rotor side includes a rotor case 6, a magnet 7, a shaft 8, and the like.

A ball bearing 10 supported by a bearing support 9 of the housing 1 and a ball bearing 12 supported by a bearing support 11 of the end bracket 2 are provided with a shaft 8.
Is supported. The boss 13 of the rotor case 6 is fitted and fixed to the shaft 8. A knurl 14 (unevenness) is formed on the outer peripheral surface of the shaft 8 to which the boss 13 is fitted. With this knurl 14, the shaft 8 and the boss 1
3 are connected and detent is performed. The diameter of the shaft is 8 mm.

The shaft collar 15 fitted on the outer periphery of the shaft 8 is connected to the ball bearing 12 on the end bracket 2 side.
Are arranged so as to come into contact with the abduction member 16. Shaft 8
The shaft collar 17 fitted on the outer periphery of the ball bearing 10 is in contact with the external rotation member 18 of the ball bearing 10 on the housing 1 side. The fixed side member 19 of the ball bearing 12 on the end bracket 2 side and the bearing support 11 on the end bracket 2 side
And a spring seat 20 is interposed therebetween.
The rotor case 6 is supported by predetermined positions of the housing 1 and the end bracket 2 and rotated by the shaft collar 15, the shaft collar 17, the spring seat 20, and the like.

The air conditioner shown in FIG. 2 is an embodiment in which a motor 30 having a length of 1, a diameter of d, and an inertia i embodying the present invention is mounted. A fan 41 having a diameter D and an inertia I is supported by two bearings 42 and 43, and is connected to a motor shaft 8 by a coupling 44.

The air conditioner is roughly constituted by a fan 41 connected to the motor 30, a heat exchanger 45 surrounding the fan 41, and a cover 46 for housing the whole.

The details of each unit will be described below.

The housing 1 is formed of a steel plate having a thickness of 1.2 mm. The housing 1 including the bearing support portion 9 and the outer cylindrical portion 21 is integrally formed by press working.

The end bracket 2 is formed of a steel plate having a thickness of 1.2 mm. Bearing support 11 and protrusion 2
2 and the end bracket 2 are integrally formed by press working.

The core holder 3 is formed of a steel plate having a thickness of 1 mm. The core holder 3 including the fitting part 23 to the end bracket 2 and the fixing part 24 of the stator core 4 is integrally formed by press working.

The stator core 4 is formed by laminating a number of electromagnetic steel plates punched into a predetermined shape and fastening them. After the stator core 4 contacts the insulator 25, a magnet wire is wound around the stator core 4 to form the stator coil 5. Also, the electronic component 27 is attached to the support 26 having a part of the insulator 25 extended.
Is mounted and fastened to the fixing portion 24 of the core holder 3.

The rotor case 6 is formed of a steel plate having a thickness of 1 mm. The rotor case 6 including the boss 13 and the outer cylindrical portion 29 is integrally formed by press working.

The magnet 7 is formed by mixing ferrite or neodymium or the like with a resin as a base material, is formed in a ring shape, and is magnetized so that N and S magnetic poles are alternately repeated. The magnet 7 is arranged so as to fit on the inner circumference of the outer cylindrical portion 29 of the rotor case 6, and is fixed with an adhesive. Since the magnet 7 is arranged on the inner periphery of the outer cylindrical portion 29, the magnet 7 is not damaged by centrifugal force during rotation.

The motor in which the stator 4 and the magnet 7 are arranged as described above is called an outer rotor type motor. Compared with the inner rotor type motor, there is a feature that the magnet 7 can be set substantially on the outer peripheral side of the motor. Therefore, the cross-sectional area of the magnet (= magnetic force)
And the number of poles of the stator 4 can be increased. As a result, the output of the motor is increased in the case of the same volume product, and the thickness of the motor is reduced in the case of the same output. Furthermore, as the diameter of the rotor case 6 and the magnet 7 increases, the inertia / volume ratio increases, so that the advantage of improving the rotation unevenness can be obtained.

In order to demonstrate the effects based on the present invention, a load of 1,400 gf · cm, a rotation speed of 1,450 min- ¹ ,
A fan motor with an output of 21 W was manufactured and its characteristics were compared. As a result, the fan diameter D {92 mm, the motor diameter d}
At 92 mm, the length 1 of the motor was 26 mm (fan diameter ratio = 28%). The axial length of the conventional inner rotor type motor is about 40 mm (fan diameter ratio = 43%)
Therefore, the size was reduced by 35%.

The inertia of the fan I = 7,800 g · c
m ² , inertia i = 4 of the conventional inner rotor type motor
Where 50 g · cm ² , fan inertia ratio = 6%, motor inertia i = 1,200 g · cm ² , fan inertia ratio = 15%
And became bigger. As a result, at low speed rotation ($ 500mi)
It was found that the rotational unevenness of n- ¹ ) was improved from 0.53% to 0.40%.

The stator 4 and the stator coil 5
The connection between the motor and the control circuit 28 and the operation principle of the brushless motor are well-known, and are not directly related to the present invention.

[0025]

As described in detail in the text, the structure of the brushless motor is made to be the outer rotor type, so that the axial dimension of the motor becomes small and the inertia becomes large, so that the uneven rotation can be improved, and the industrial waste can be improved. A brushless motor made of steel plate, which can be easily treated as a material, has been put to practical use.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a state in which the brushless motor shown in FIG. 1 is incorporated in an air conditioner.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Housing, 2 ... End bracket, 3 ... Core holder, 4 ... Stator core, 5 ... Stator coil, 6 ... Rotor case, 7 ... Magnet, 8 ... Shaft.

Claims (1)

[Claims] An outer rotor comprising: a stator core having a plurality of core teeth on which a stator coil is wound; and a rotor having a plurality of permanent magnet magnetic poles arranged to face an outer periphery of the core teeth. A brushless motor for a fan, wherein the axial length ratio of the motor is set to 30% or less of the fan diameter and the inertia ratio of the motor is set to 10% or more of the fan.