JPH05211754A - Brushless motor - Google Patents

Abstract

PURPOSE:To lighten an brushless motor and save the space, in a circuit integrated brushless motor where a driving circuit including a power element is constituted on a printed circuit. CONSTITUTION:This is so constituted that a printed board 3, which has a driving circuit including a power element, is attached to partial or entire periphery of the iron core of a stator. A light, space-saving, long-life, and reliable brushless motor can be materialized, making use of the stator iron core and the stator winding 2 as heat radiators.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor incorporating a drive circuit including a power element.

[0002]

2. Description of the Related Art In recent years, replacement of commutator motors and induction motors with brushless motors that are maintenance-free, efficient, and excellent in variable speed has been rapidly progressing due to higher functionality of products. In addition, a brushless motor with a built-in circuit has been commercialized.

As a conventional brushless motor, a structure as shown in Japanese Patent Laid-Open No. 3-89837 has been generally used.
The conventional brushless motor will be described below.

FIG. 3 shows the structure of a conventional brushless motor. In quoting, the outer shape of the stator core was changed from a circular shape to a quadrangular shape. In FIG. 3, 1 is a stator iron core, 2 is a stator winding, 3 is a printed circuit board on which electronic components including a position detection element 6 are mounted, 4 is a radiator for radiating power elements, and 5 is an inner cylindrical portion of the radiator 4. It is a resin that seals the entire motor except for.

The operation of the brushless motor constructed as above will be described below. In the case of the circuit-integrated type, it is the temperature of the power element, which is a semiconductor and a heating element, that must be careful of the temperature rise. First, when the brushless motor rotates and does work, the heat generated in the drive circuit including at least the power element is transmitted to the radiator 4 by heat conduction, and is further radiated into the air through the resin 5 to reach the saturation temperature with the passage of time.

[0006]

However, in the above-mentioned conventional structure, since the radiator has a radiator, the volume of the circuit-integrated brushless motor becomes large, and the commutator motor and the induction motor cannot be replaced in a device having a small space. Had a problem.

The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a lightweight and space-saving circuit-integrated brushless motor.

[0008]

To achieve this object, the brushless motor of the present invention has a structure in which a printed circuit board is attached in close contact with part or all of the outer peripheral surface of a stiff iron core.

[0009]

With this structure, the heat radiation area is expanded, and the heat generated by the drive circuit including the power element can be efficiently radiated by using the printed circuit board, the stator core and the stator winding as a heat radiator.

[0010]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. The same components as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 1, 7 is a metal-based printed circuit board, and 8 is a sub-printed circuit board. The printed circuit board 3 has all the power elements and its drive circuit mounted, and is bent to the side surface side of the stator core 1 and also to the upper surface side and the lower surface side, and a compound having good thermal conductivity is applied between the stator core 1 and the printed circuit board 3. Then, the stator core 1 is attached while ensuring heat dissipation. In addition, the sub printed circuit board 8
Is equipped with a position detection element 6. In the assembly of the entire motor, the inner cylindrical portion is removed with resin 5 and the stator core 2 assembled with the stator winding 2 and the printed circuit board 3 and the sub printed circuit board 7 are sealed.

The operation of the brushless motor configured as described above will be described with reference to FIG. First, when the brushless motor rotates, heat is generated in the power elements in the drive circuit due to ON loss and switching loss, and the generated heat is generated in the stator core 1 and the stator winding 2 and the resin 5 by the printed circuit board 3 having good thermal conductivity. It is transmitted and released into the air.

As described above, according to this embodiment, since the stator iron core 1 and the stator windings 2 that transfer and radiate heat from the printed circuit board 3 are used as radiators, a radiator for heat radiation is unnecessary.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings. In addition, Example 1
The same components as those of are denoted by the same reference numerals, and the description thereof will be omitted.

In FIG. 2, 9 is a ceramic or metal-based printed circuit board, and 10 is a flexible printed circuit board. The printed circuit board 9 is different from that of the first embodiment.
This is the point where the flexible printed circuit board 10 is connected separately. The method of mounting the printed circuit board 9 on the stator core and the method of sealing the motor with the resin 5 are the same as in the first embodiment.

According to this method, the printed circuit board 9
Ceramic, which is a rigid material, can also be used. That is, it is possible to configure a brushless motor capable of selecting a wide range of materials. Further, although the printed circuit board 9 is connected by the flexible printed circuit board 10, a printed circuit board of the type in which the entire printed circuit board 9 is configured by the flexible printed circuit board and a part thereof is lined with a metal plate may be used.

The operation of the brushless motor configured as described above will be described with reference to FIG. Example 1
Similarly to the above, the heat generated in the drive circuit is transmitted from the printed circuit board 9 having good thermal conductivity to the stator core 1, the stator winding 2 and the resin 5, and is radiated into the air.

As described above, according to this embodiment, the first embodiment
The heat radiator for heat radiation becomes unnecessary like the above.

[0019]

As is apparent from the above description of the embodiments, the present invention uses the stator iron core and the stator windings as the radiator of the printed circuit board, so that the radiator for radiating the heating element is unnecessary. It is lightweight and space-saving, and can realize an excellent brushless motor.

[Brief description of drawings]

1A is a plan view of a brushless motor according to a first embodiment of the present invention, FIG. 1B is a side view of FIG. 1A, and FIG. 1C is a sectional view taken along line AA of FIG.

2A is a plan view of a brushless motor according to a second embodiment of the present invention, FIG. 2B is a side view of FIG. 2A, and FIG. 2C is a sectional view taken along line AA of FIG.

FIG. 3A is a plan view of a conventional brushless motor, and FIG. 3B is a side view of FIG.

[Explanation of symbols]

 1 Stator core 7 Printed circuit board 9 Printed circuit board 10 Flexible printed circuit board

Claims (2)

[Claims] 1. A brushless motor in which a drive circuit including a power element is formed on a printed circuit board, and the printed circuit board is attached in close contact with part or all of the outer peripheral surface of a stator core. 2. The brushless motor according to claim 1, wherein the printed circuit board is divided and connected by a flexible printed circuit board.