JPH08317604A - Electric motor - Google Patents

Abstract

PURPOSE: To protect the electronic parts such as Hall ICs and the like by removing the static electricity charged in a rotor readily. CONSTITUTION: At least one bearing bracket 7 is made of metal. A substrate 1, wherein a grounding pattern is provided, is inserted between the bearing bracket 7 formed of the metal and a stator 5. When the bearing bracket 7 is pressed in and fixed to the stator 5, the substrate 1 is held by the stator 5 and the bearing bracket 7. Thus, the grounding pattern and the bearing bracket 7 are electrically connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor having a mechanism in which a rotor is held by a ball bearing housed in two bearing brackets, the bearing bracket is fixed to a stator, and the rotor is rotatable.

[0002]

2. Description of the Related Art An electric motor used for an air conditioner or the like has a hall element or a hall IC incorporated therein to detect the rotational speed and control the speed. However, there is a possibility that the rotor of the electric motor is charged with static electricity, and this static electricity affects the pattern of the substrate on which the Hall IC or the like is provided, and the Hall IC or the like is destroyed.

As a countermeasure against the destruction of the hall element and the like, a ground wire is attached to the bearing bracket. This conventional electric motor will be described with reference to FIG. FIG. 6 is a partial cross-sectional view of a conventional electric motor.

In FIG. 6, an electric motor 15 includes a stator 19 in which a core 17 having windings 16 is formed by a premix 18, a rotor 20 disposed inside the stator 19,
A bearing bracket 7 fixed to both side surfaces of a stator 19 for holding the rotor 20, and a ball bearing housed in a ball housing 7a of the bearing bracket 7 and provided to allow the rotor 20 to rotate. 8 and a magnet 21 attached to the rotor 20
And a Hall IC 9 for detecting the magnetism of the magnet 21, and a substrate 25 provided between one bearing bracket 7 and the stator 19. Also,
The substrate 25 is sandwiched and fixed by the stator 19 and the bearing bracket 7. The power supply line 28 is connected to the winding 16 and supplies electric power to the winding 16. The three control lead wires 10 are connected to the Hall IC 9 and
Power is supplied to C9, and the signal output from the Hall IC9 is transmitted to an external control circuit.

A grounding screw 26 is attached to the bearing bracket 7 and a rotor 2 is attached by a grounding wire 27 attached to the grounding screw 26.
0 is grounded via a bearing bracket 7 and a ball bearing 8.

[0006]

However, in the conventional structure, when the ground screw is screwed into the bearing bracket, the cutting chips generated from the bearing bracket may enter the stator and cause noise. Further, when a load such as a fan is attached to the surface side to which the ground screw is attached, the ground screw may become an obstacle.

[0007]

Therefore, according to the present invention, at least one of the bearing brackets is made of metal, and a substrate having a ground pattern is provided between the bearing bracket made of metal and the stator. When the bearing bracket is press-fitted and fixed to the stator, the stator and the bearing bracket sandwich and fix the substrate to electrically connect the ground pattern and the bearing bracket. An electric motor characterized by being connected to.

Alternatively, the bearing bracket and the substrate are adhered with an adhesive, the substrate and the bearing bracket are fixed to a stator, and the earth pattern and the bearing bracket are electrically connected. Electric motor.

Alternatively, solder is applied on the ground pattern of the substrate, the bearing bracket is heated, the bearing bracket and the ground pattern are soldered, and the substrate and the bearing bracket are fixed to a stator, Provided is an electric motor characterized in that an earth pattern and a bearing bracket are electrically connected.

[0010]

[Operation] The bearing bracket is pressed into the stator.
At this time, the substrate is inserted between the bearing bracket and the stator. Further, the ground pattern provided on the board is inserted toward the bearing bracket side. And
Fix the board with the bearing bracket to the stator. Then, when the bearing bracket is fixed to the stator, a part of the bearing bracket contacts the ground pattern of the substrate, and the ground pattern and the bearing bracket are electrically connected. That is, the rotor and the ground pattern are electrically connected via the bearing bracket and the ball bearing.

In order to connect the earth pattern and the bearing bracket more securely, the bearing bracket and the substrate are fixed with an adhesive. Alternatively, apply solder to the ground pattern and solder the ground pattern and the bearing bracket.

[0012]

Embodiments of the present invention will be described with reference to FIGS. FIG. 1 is a front view of a substrate according to the present invention. FIG. 2 is a partial cross-sectional view of the electric motor according to the first embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view of a connecting portion between the substrate and the bearing bracket in FIG. FIG.
It is an expanded sectional view of an adhesion part of a substrate and a bearing bracket in a 2nd example of the present invention. Figure 5: It is an expanded sectional view of a soldering part of a substrate and a bearing bracket in a 3rd example of the present invention.

In FIG. 1, on one surface of a substrate 1, a circular ground pattern 2 having a copper foil exposed on the surface is provided. A ground wire 3 is connected to the ground pattern 2. A Hall IC 9 for detecting the rotation speed is provided on the other surface (back surface in the figure). The three control lead wires 10 are connected to the Hall IC 9 as in the conventional case.

A first embodiment will be described with reference to FIGS. 2 and 3. The electric motor 4 is composed of a stator 5, a rotor 6, a bearing bracket 7, a ball bearing 8 and a substrate 1 as in the conventional case. The bearing bracket 7 on the side into which the substrate 1 is inserted is made of metal.

The substrate 1 is arranged on the stepped portion 5a of the stator 5 with the ground pattern 2 facing the outside of the stator 5. Then, the metal bearing bracket 7 is pressed into the stator 5 and fixed. At this time, a part of the bearing bracket 7 is brought into contact with the ground pattern 2 of the substrate 1. That is, when the bearing bracket 7 is fixed to the stator 5, the bearing bracket 7 and the ground pattern 2 are electrically connected.

In order to bring the bearing bracket 7 and the earth pattern 2 into contact with each other more reliably, the bearing bracket 7 and the substrate 1 may be fixed to each other.

That is, as a second embodiment, as shown in FIG. 4, the adhesive 11 is applied to a part of the substrate 1 or a part of the bearing bracket 7 to fix the substrate 1 and the bearing bracket 7 together. Good.

Alternatively, as a third embodiment, as shown in FIG. 5, the solder 12 is applied on the ground pattern 2 and the bearing bracket 7 is heated to solder the bearing bracket 7 and the ground pattern 2. ,
The substrate 1 and the bearing bracket 7 may be fixed to each other.

[0019]

According to the present invention, the cutting dust is not generated from the bearing bracket, and the cause of noise can be eliminated. Further, since there is no protrusion such as a ground screw from the electric motor, it is easy to attach a load such as a fan.

[0020]

[Brief description of drawings]

FIG. 1 is a front view of a substrate according to the present invention.

FIG. 2 is a partial cross-sectional view of an electric motor according to the first embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of a connecting portion between a board and a bearing bracket in FIG.

FIG. 4 is an enlarged cross-sectional view of a bonded portion between a substrate and a bearing bracket according to a second embodiment of the present invention.

FIG. 5 is an enlarged sectional view of a soldering portion of a board and a bearing bracket according to a third embodiment of the present invention.

FIG. 6 is a partial cross-sectional view of a conventional electric motor.

[Explanation of symbols]

 1, 25 ... Substrate 2 ... Ground pattern 3, 27 ... Ground wire 4, 15 ... Electric motor 5, 19 ... Stator 6, 20 ... Rotor 7 ... Bearing bracket 8 ... Ball bearing 9 ... Hall IC 10 ... Control lead wire 11 ... Adhesive 12 ... Solder 16 ... Winding 17 ... Core 18 ... Premix 21 ... Magnet 26 ... Ground screw 28 ... Power wire

Claims (3)

[Claims] 1. An electric motor having a mechanism in which a rotor is held by a ball bearing housed in two bearing brackets, the bearing bracket is fixed to a stator, and the rotor is rotatable. The bearing bracket is formed of metal, between the bearing bracket formed of this metal and the stator, a substrate provided with an earth pattern is inserted, and when the bearing bracket is press-fitted and fixed to the stator, An electric motor characterized in that the ground pattern and the bearing bracket are electrically connected by sandwiching and fixing the substrate with the stator and the bearing bracket. 2. The bearing bracket and the substrate are bonded together with an adhesive, the substrate and the bearing bracket are fixed to a stator, and the ground pattern and the bearing bracket are electrically connected. The electric motor according to claim 1. 3. A solder is applied to the ground pattern of the substrate, the bearing bracket is heated, the bearing bracket and the ground pattern are soldered, and the substrate and the bearing bracket are fixed to a stator, The electric motor according to claim 1, wherein the ground pattern and the bearing bracket are electrically connected.