JPH06121507A - Brushless motor - Google Patents

Abstract

PURPOSE:To provide a light and compact brushless motor in which the drive circuit including a power element is formed integrally on a printed board. CONSTITUTION:A motor drive power element 19 mounted on a printed board 18 is fixed through an insulating sheet 20 to a heat dissipation fin 21 which is fit tightly to a bracket 1. Consequently, heat produced from the power element at the time of driving a motor is transmitted through the fin 21, the bracket 11, the stator 5 and the winding 3 and dissipated efficiently. Furthermore, when a high stature component constituting a drive circuit is mounted on the power element mounting face of the printed board 18 whereas low stature components are mounted on the rear, external noise can be blocked resulting in a light and compact brushless motor having long service life and high reliability.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In recent years, electric appliances have been rapidly replaced by brushless motors, which are efficient and easy to change gears, in place of high functionality electric appliances, instead of induction motors.

A conventional brushless motor will be described below. FIG. 2 shows the structure of a conventional brushless motor. In FIG. 2, 1 is a bracket, 2 is a bearing, 3 is a winding wire, 4 is a holding base having a built-in position sensor, 5
Is a stator, 6 is a rotor, 7 is a cable, and 8 is a motor drive circuit. In a conventional brushless motor, a rotor 6 having a bearing 2 mounted as a motor portion is housed in a stator 5 having a winding 3, and is rotatably held by a bracket 1. A position sensor for detecting the rotor position is built in the holding table 4 attached to the bracket 1 and is attached so as to face the rotor magnet. On the other hand, the drive circuit 8 is provided outside the motor, and the space between the drive circuit 8 and the motor section is
Connected with 0 or more lead wires.

[0004]

However, in the above-mentioned conventional configuration, the position detection signal line is externally provided in a large installation space, so that it is affected by noise. On the other hand, if a circuit is built in the motor in order to solve this problem, heat generation in the circuit becomes an obstacle, and a large radiator is required, resulting in an increase in the size of the motor.

The present invention solves the above problems,
An object of the present invention is to provide a compact circuit-integrated brushless motor having good heat dissipation.

[0006]

In order to achieve this object, the brushless motor of the present invention has a structure in which a radiation fin is separately attached to a power element and integrally formed, and the radiation fin is closely attached to the inner surface of the bracket. Have

[0007]

With this structure, the heat generated by the power element, which is the heat generating element, is generated by mounting the radiation fin integrated with the power element in close contact with the bracket. The heat is transferred to the wires, and the heat generated by the power element can be efficiently dissipated.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a bracket, 2 is a bearing, 3 is a winding wire, 4 is a holding base having a built-in position sensor,
Reference numeral 5 is a stator, 6 is a rotor, 17 is a cable, 18 is a printed circuit board on which a power element 19 is mounted, 20 is an insulating sheet, 21 is a radiation fin, 22 is a tall component, and 23 is a short component. As a motor structure, a rotor 6 having a bearing 2 mounted therein is housed in a stator 5 having a winding 3, and is rotatably held by a bracket 1. And
The position sensor for detecting the rotor position is built in the holding table 4 attached to the bracket 1 and is attached so as to face the rotor magnet. Further, the radiation fin 21 is the insulating sheet 2
It is attached to the power element 19 with 0 interposed therebetween, and further attached so as to be in close contact with the inner surface of the bracket 1.

With respect to the brushless motor configured as described above, the radiation fin 21 integrated with the power element 19 is provided.
The heat dissipated by the heat dissipating fins 2 is generated by heat conduction of the power element 19 which is a heat generating element.
1, heat is transferred to the bracket 1, the stator 5 and the winding 3, and the heat generated by the power element 19 can be efficiently dissipated.

Mounting of electronic components on the printed circuit board 18
As shown in the figure, the relatively tall component 22 is mounted on the power element mounting surface, and the chip resistor / chip capacitor, which is the short component 23, is mounted on the solder surface, which is the back surface thereof, and compactly mounted in the bracket 1. is doing. Power element 1
No. 9 is not a surface mount product, but a normal type can be used.

Needless to say, if the external fan is forcibly cooled by air, the heat dissipation is further enhanced.

In order to secure heat dissipation, the printed circuit board 18 may be attached to the bracket 1 by applying a compound having good thermal conductivity.

[0014]

As described above, according to the present invention, by utilizing the bracket, the stator and the winding as a radiator, heat is efficiently radiated, and a large radiator is unnecessary. Further, since the circuit is integrally built in the motor, the position detection signal line is not exposed to the outside, so that it is not affected by noise and complicated wiring is not required outside. Therefore, the configuration of the present invention can realize a brushless motor that is easy to handle, lightweight, and compact.

[Brief description of drawings]

FIG. 1A is a structural diagram of a brushless motor according to an embodiment of the present invention. FIG. 1B is a detailed structural diagram of an A portion in FIG. 1A.

FIG. 2 is a structural diagram of a conventional brushless motor.

[Explanation of symbols]

 1 bracket 2 bearing 3 winding 4 holding stand 5 stator 6 rotor 7 cable 8 drive circuit 17 cable 18 printed circuit board 19 power element 20 insulating sheet 21 radiating fin 22 tall component 23 short component

Claims (1)

[Claims] 1. A brushless motor including a stator having a winding, a rotor having a bearing mounted thereon, a bracket holding the bearing, and a drive circuit,
A drive circuit including a power element is configured on a printed circuit board,
A circuit-integrated brushless motor in which a radiation fin is separately attached to the power element to be integrally configured, and the radiation fin is closely attached to the inner surface of the bracket.