JPH0638432A - Method for connecting grounding of direct current brushless motor - Google Patents

Abstract

PURPOSE:To easily and surely ground a motor case and metal board by press fitting a metallic bearing member in a way that it is in contact with an inside circumferential conductor pattern and press fitting the metal board into a metallic motor frame. CONSTITUTION:An insulating layer is formed on the surface of a metal base, and a copper foil conductor pattern is formed thereon. A conductor pattern for grounding is formed on the inside circumference and connected to a grounding terminal. A lower bearing 12, when press fit into a metallic circuit board 9, comes into contact with the conductor pattern for grounding and the metal base to provide grounding. The metallic circuit board 9 is then fitted, and secured in a metallic motor case 2, which is thereby grounded through the conductor pattern for grounding and the grounding terminal. The constitution above makes it possible to ground the motor case 2 just by building the metallic circuit board 9 thereinto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC brushless motor incorporated in various electronic devices, and more particularly to a method for grounding a DC brushless motor using a metal substrate as a circuit substrate.

[0002]

2. Description of the Related Art In recent years, in small DC brushless motors incorporated in audio equipment and OA equipment, an example of using a metal substrate as a circuit substrate in order to improve heat dissipation characteristics of a drive circuit is increasing. In addition, a metallic motor case is used as a housing to shield radiation noise generated from the rotor as the motor rotates. Therefore, conventionally, as shown in FIG. 4, the lead wire 16 is directly attached to the motor case 2.
The motor case is grounded by soldering or the like, or by connecting a back cover made of iron or the like to the motor case and soldering a lead wire to the back cover or spot welding.

[0003]

By the way, when the lead wire is directly soldered to the motor case or grounded by spot welding as described above, the synthetic resin portion of the motor is removed by the heat accompanying the soldering or the like. Deformation and discoloration,
Alternatively, the molten synthetic resin may be scattered to impair the appearance of the motor.

In addition, direct soldering to a metallic motor case and a metallic substrate causes a large amount of heat dissipation, resulting in defective soldering such as so-called immo solder, and it takes time for soldering, resulting in work efficiency. There was a problem that was bad.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a motor capable of easily and reliably grounding a metal motor case forming a part of a motor and a metal substrate. And

[0006]

To achieve this object, a DC brushless motor of the present invention comprises a metal base used as a circuit board, the surface of which is insulated, and a conductor circuit is formed on the insulator. The grounding pattern of the metal base circuit board is provided on the inner peripheral portion of the disc-shaped board, and the metal bearing member is press-fitted and fixed so as to be in contact with the inner peripheral conductor pattern. Is electrically connected, and the motor case is grounded through the conductor pattern and the ground terminal by press-fitting and fixing the metal substrate on the metal motor frame.

[0007]

According to the above-mentioned structure, the motor case can be grounded simply by mounting the circuit board in the motor case and mounting it.

[0008]

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

In FIG. 1, reference numeral 1 is a shaft, 2 is a motor case, and 3 is an upper bearing press-fitted and fixed to the motor case 2, and rotatably supports the shaft 1 together with a lower bearing 12. Reference numeral 4 is a multi-pole magnetized cylindrical permanent magnet, 5 is a rotor frame to which the cylindrical permanent magnet 4 is fixed, and the rotor frame 5 is fixed to the shaft 1. Reference numeral 6 denotes an iron core composed of a plurality of sheets, and 7 denotes an insulating member that electrically insulates the iron core 6 so as to cover the iron core 6. Reference numeral 8 denotes a copper wire wound around the iron core 6 via the insulating member 7 and constitutes a fixed armature. Reference numeral 9 is a metal circuit board, and 10 is an IC which is one of drive circuit elements, and is mounted on the metal circuit board 9 in the peripheral portion of the fixed armature. Reference numeral 11 is a fixing member that fixes the fixed armature to the metal circuit board 9 and receives the thrust of the shaft 1.

FIG. 2 is a detailed view of a portion A in the embodiment of FIG. 1, in which an insulating layer 14 is formed on the surface of the metal base 13.
Copper foil conductor patterns 15a and 15b are formed thereon. Here, the conductor pattern of 15a is connected to the ground terminal. The lower bearing 12 is press-fitted into the metal circuit board 9 and contacts the conductor pattern 15a to be grounded, and also contacts the metal base 13 to ground the metal base.

Next, FIG. 3 is a detailed view of a portion B in the embodiment of FIG. 1, in which the metal circuit board 9 is fitted into the motor case 2 and is caulked and fixed at the motor case end portion 2a.

Further, the conductor pattern in FIG. 2 may be a conductor pattern plated with gold or silver.

[0013]

As described above, according to the present invention, the motor case can be easily and surely grounded only by changing the conductive pattern of the circuit board by the above-described structure, and especially the lead for grounding the motor case is provided. The cost of the motor can be reduced without requiring special parts such as wires, and the work can be simplified because a special grounding step such as spot welding is not particularly required.

Further, by grounding the conductor pattern provided on the inner peripheral portion of the metal substrate to the metal base having a large heat capacity through the metal bearing member, the heat dissipation of the circuit can be improved.

[Brief description of drawings]

FIG. 1 is a ground connection method for a DC brushless motor according to an embodiment of the present invention.

FIG. 2 is a detailed view of part A of the embodiment of the present invention in FIG.

FIG. 3 is a detailed view of part B of the embodiment of the present invention in FIG.

[Fig. 4] Conventional ground connection method

[Explanation of symbols]

 1 Shaft 2 Motor Case 3 Upper Bearing 4 Permanent Magnet 5 Rotor Frame 6 Iron Core 7 Insulating Member 8 Copper Wire 9 Metal Circuit Board 10 IC 11 Thrust Fixing Member 12 Lower Bearing 13 Metal Base 14 Insulating Layer 15 Conductor Pattern

Claims (1)

[Claims] 1. A grounding pattern for a metal base circuit board, which is obtained by insulating a surface of a metal base and forming a conductor circuit on the insulator, is provided on an inner peripheral portion of a disk-shaped substrate. By electrically connecting the grounding conductor pattern and the metal base by press-fitting and fixing a metal bearing member so as to abut the pattern, and by press-fitting and fixing the metal substrate to the metal motor frame. A grounding method for a DC brushless motor, characterized in that the motor case is grounded via the conductor pattern and the ground terminal.