JPH07284260A - Brushless motor - Google Patents

Abstract

PURPOSE:To provide a motor which facilitates a high output and the improvement of the reliability while the reduction of the weight, thickness, length and size of the motor is achieved. CONSTITUTION:A stator core 1 to which a stator winding 3 is applied and a printed wiring board 4 on which driving circuit components, etc. are mounted are molded integrally with synthetic resin having electrically insulating properties to obtain a stator. Among the drive circuit components, heat generating devices such as power devices are so positioned as to extend partially or totally from the outer circumference of the stator core 1 to increase the outside surface area of the heat generating device part of the motor. Thus the brushless motor can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor used as a blower fan drive source for a home air conditioner or the like.

[0002]

2. Description of the Related Art In recent years, in air conditioners such as home air conditioners, it is becoming mainstream to control the capacity of a compressor.

In response to this, it is required to widely adjust the amount of air blown to the heat exchanger in multiple stages. Instead of the induction motor as a fan drive source that has been conventionally used to satisfy these demands. Therefore, a method of operating a brushless motor whose speed is easily adjusted by a DC power source is being adopted.

On the other hand, there are strong demands for higher output and higher reliability as well as a lighter, thinner, shorter and smaller motor.

A conventional brushless motor finished product has a structure as shown in the vertical sectional view of FIG. 12, and is fixed to a printed wiring board 4 on which a driving circuit component 5, a position detecting element 6 and the like are mounted, and an insulating layer 2. The stator core 1 provided with the child winding 3 is integrally molded and solidified with the synthetic resin 15 having an electric insulation property to form a stator finished product 20, and the permanent magnet rotor 21 is formed by the bearing devices 22 and 23. A brushless motor is supported to support noise reduction and downsizing.

An example of the brushless motor having such a structure is disclosed in Japanese Patent Laid-Open No. 61-251462.

An example of a conventional brushless motor will be described below with reference to the drawings. FIG. 13 is a perspective view of the brushless motor shown in FIG. 12 when the stator is assembled. The stator core 1 is provided with a stator winding 3 through an insulating layer 2, while the printed wiring board 4 is provided with drive circuit components. 5, electronic components such as the position detection element 6, the fixed resistor 8, the jumper wire 9, the capacitor 10 and the like are mounted on the same surface, and the drive circuit component 5 and the electronic components are mounted on the teeth and teeth of the stator core 1. Between the parts, that is, in the space between the stator winding 3 and the stator winding 3, and the surface of the printed wiring board 4 on which electronic components are mounted is the end surface of the stator core 1. The printed wiring board 4 and the stator core 1 are mounted facing each other.

FIG. 14 is a vertical sectional view and a perspective view of a completed stator of a brushless motor, in which the stator core 1, the stator winding 3, the drive circuit component 5, and the position detecting element 6 are mounted. The printed wiring board 4 is integrally molded and solidified with a synthetic resin 15 to form a finished stator product 20.

Here, the drive circuit component 5 is a one-chip IC having a built-in power element and is a heating element.

In the conventional brushless motor having such a structure, it has been known that the maximum output of the motor is limited by the allowable loss in the heating element even if the motor has a margin of physical size.

[0011]

With the above structure, the following problems occur. (1) Since the heating element is located between the windings,
The ambient temperature around the heating element rises due to the heat generated by the winding, and the allowable loss of the heating element itself decreases. (2) Since the periphery of the heating element is surrounded by the synthetic resin and is located between the windings at the same time, the heat radiation of the heating element is not sufficiently performed.

When the maximum output is to be increased by the above two points, the output cannot be increased by increasing the current. (3) In many cases, the heat-generating element is not sufficiently dissipated of heat, and the heat-generating element is often used in the vicinity of the limit of the allowable loss.

An object of the present invention is to provide a brushless motor which solves the above-mentioned conventional problems, increases the maximum output, and has improved reliability.

[0014]

In order to solve this problem, the brushless motor of the present invention has the following structure.

The stator core provided with a stator winding and a stator formed by integrally molding and solidifying a printed wiring board on which components for driving circuits are mounted with synthetic resin having electric insulation are provided. Among the circuit components, the position of a heat generating element such as a power element is arranged so as to partially or entirely project from the outer diameter of the stator core, and the surface area of the motor outer shell of the heat generating element portion is increased.

[0016]

With the above configuration, the heat dissipation of the heat generating element can be sufficiently performed without being affected by the rise in the ambient temperature due to the heat generation of the winding, and the allowable loss of the heat generating element can be increased.

[0017]

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

The same components as those shown in FIGS. 12, 13 and 14 are designated by the same reference numerals, and the description thereof will be omitted.

(Embodiment 1) FIG. 1 is a vertical sectional view of a completed brushless motor according to an embodiment of the present invention.

A synthetic resin 15 having an electric insulation property is provided between the printed wiring board 4 on which the drive circuit component 5 and the position detecting element 6 are mounted, and the stator core 1 on which the stator winding 3 is provided via the insulating layer 2. Finished product of the stator 20
And a permanent magnet rotor 21 is supported by bearing devices 22 and 23 to form a brushless motor.

FIG. 2 is a perspective view of the brushless motor shown in FIG. 1 when the stator is assembled. The stator core 1 is provided with a stator winding 3 through an insulating layer 2, while the printed wiring board 4 is provided.
Drive circuit component 5, position detection element 6, fixed resistor 8,
Electronic components such as jumper wires 9 and capacitors 10 are mounted on the same surface, and the electronic components are mounted between the teeth of the stator core 1, that is, the stator winding 3 and the stator winding 3 It is arranged so as to be located in the space between.

All or part of the drive circuit component 5 is arranged so as to project from the outer diameter of the stator core 1, and the surface of the printed wiring board 4 on which the electronic components are mounted is the end face of the stator core 1. The printed wiring board 4 and the stator core 1 are mounted facing each other.

3 to 11 show examples of a vertical cross-sectional view and a perspective view of a completed stator of a brushless motor according to the present invention.

In FIG. 3, the printed wiring board 4 on which the stator core 1, the stator winding 3, the drive circuit component 5 and the position detecting element 6 are mounted is integrally molded and solidified with a synthetic resin 15. To form a finished stator product 20.

Since all or part of the drive circuit component 5 is arranged so as to project from the outer diameter of the stator core 1, the surface area is increased and the heat dissipation is improved.

In the example of the present invention, the drive circuit component 5 is a heat generating element which is a one-chip IC with a built-in power element, but it goes without saying that any heat generating element such as a power transistor may be used. Nor.

FIG. 4, FIG. 5, and FIG. 6 show an example in which the shape of the motor outer shell of the heating element portion is formed in the shape of one or a plurality of heat radiating plates.

By doing so, the surface area is further increased and the heat dissipation is further improved. Needless to say, when strength is required and the shape of the heat dissipation plate cannot be obtained, ribs may be provided as shown in FIG. 7 to reinforce and the shape of the heat dissipation plate may be substituted.

Similarly, when strength is required and the shape on the heat sink cannot be formed, even if the surface area is increased by forming regular or irregular unevenness or steps as shown in FIGS. 8 and 9. good.

(Embodiment 2) FIGS. 10 and 11 are a longitudinal sectional view and a perspective view of a finished stator of a second brushless motor of the present invention.

10 and 11, a radiator plate 30 such as a heat sink is attached to the heat generating element with a close contact or a material having a high thermal conductivity interposed, and the radiator plate 30 is projected on the surface of the motor outer shell or outward. It is an example that is configured.

By doing so, the heat of the heat generating element is radiated through the heat radiating plate 30 having good thermal conductivity,
The heat is dissipated very efficiently and the allowable loss increases.

[0033]

As described above, the following effects can be obtained by using the configuration of the present invention. (1) Since the heat generating element is arranged at a position distant from the winding, the allowable temperature of the heat generating element itself increases without the ambient temperature of the heat generating element rising due to heat generation of the winding. (2) Due to the increase in the surface area of the motor outer shell of the heating element portion, the heat radiation of the heating element is sufficiently performed.

Due to the above two points, the current can be increased and the maximum output can be increased as compared with the conventional example. (3) Since the heat radiating of the heat generating element is sufficiently performed, the same output as the conventional example can be used where there is a sufficient margin for the allowable loss of the heat generating element, and the heat generating element should be continuously used in a high temperature state. And the failure of the heating element can be prevented.

As described above, according to the present invention, high output can be realized while achieving lightness, thinness, shortness, and miniaturization, and reliability of the product can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a completed brushless motor according to an embodiment of the present invention.

FIG. 2 is a perspective view of a brushless motor according to an embodiment of the present invention when a stator is assembled.

FIG. 3A is an external perspective view of a completed stator of the brushless motor according to the first embodiment of the present invention. FIG. 3B is a vertical cross-sectional view of the completed stator of the brushless motor according to the first embodiment of the present invention.

FIG. 4A is an external perspective view of a completed stator of the brushless motor according to the first embodiment of the present invention. FIG. 4B is a vertical cross-sectional view of the completed stator of the brushless motor according to the first embodiment of the present invention.

FIG. 5A is an external perspective view of a completed stator of the brushless motor according to the first embodiment of the present invention. FIG. 5B is a vertical cross-sectional view of the completed stator of the brushless motor according to the first embodiment of the present invention.

FIG. 6A is an external perspective view of a completed stator of the brushless motor according to the first embodiment of the present invention. FIG. 6B is a vertical cross-sectional view of the completed stator of the brushless motor according to the first embodiment of the present invention.

FIG. 7A is an external perspective view of a completed stator of the brushless motor according to the first embodiment of the present invention. FIG. 7B is a longitudinal sectional view of the completed stator of the brushless motor according to the first embodiment of the present invention.

FIG. 8A is an external perspective view of a completed stator of the brushless motor according to the first embodiment of the present invention. FIG. 8B is a longitudinal sectional view of the completed stator of the brushless motor according to the first embodiment of the present invention.

FIG. 9A is an external view of a finished stator of a brushless motor according to the first embodiment of the present invention. FIG. 9B is a vertical cross-sectional view of the finished stator of the brushless motor according to the first embodiment of the present invention.

FIG. 10A is an external perspective view of a completed stator of a brushless motor according to the second embodiment of the present invention. FIG. 10B is a vertical cross-sectional view of a completed stator of the brushless motor according to the second embodiment of the present invention.

FIG. 11A is an external perspective view of a completed stator of the brushless motor according to the second embodiment of the present invention. FIG. 11B is a vertical cross-sectional view of the completed stator of the brushless motor according to the second embodiment of the present invention.

FIG. 12 is a vertical sectional view of a conventional brushless motor finished product.

FIG. 13 is a perspective view when assembling a stator of a conventional brushless motor.

FIG. 14A is an external perspective view of a finished product of a conventional brushless motor, and FIG. 14B is a vertical cross-sectional view of a finished product of a conventional brushless motor.

[Explanation of symbols]

 1 Stator Core 2 Insulating Layer 3 Stator Winding 4 Printed Wiring Board 5 Drive Circuit Parts 6 Position Detecting Element 7 Sensor Fixing Base 8 Fixed Resistor 9 Jumper Wire 10 Capacitor 13 Lead Wire Group 14 Lead Bushing 15 Synthetic Resin 20 Stator Completed product 21 Permanent magnet rotor 22,23 Bearing device 30 Heat sink

Claims (7)

[Claims] 1. A stator comprising a stator core having a stator winding, and a printed wiring board on which drive circuit parts and the like are mounted and integrally molded and solidified with a synthetic resin having an electric insulation property. Among the drive circuit parts, the position of a heating element such as a power element is arranged so as to partially or entirely project from the outer diameter of the stator core, and the surface area of the motor shell of the heating element portion is increased. Brushless motor that does. 2. A one-chip I in which a heating element has a built-in power element
The brushless motor according to claim 1, wherein the brushless motor is formed of C. 3. The brushless motor according to claim 1 or 2, wherein a rib is provided on the motor outer shell of the heating element portion. 4. The brushless motor according to claim 1, wherein the shape of the motor outer shell of the heating element portion is one or a plurality of radiator plates. 5. The brushless motor according to claim 1 or 2, wherein the surface of the motor outer shell of the heating element portion is formed in a regular or irregular concavo-convex shape. 6. The brushless motor according to claim 1 or 2, wherein the surface of the motor casing of the heating element portion is formed in a regular or irregular step shape. 7. A heat radiating plate is attached to the heat generating element or a heat radiating plate is attached with a material having a high thermal conductivity interposed, and the heat radiating plate is formed on the surface of the motor outer casing or protruding outward from the surface. The brushless motor according to claim 1 or 2.