JPS6237418Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in flat motors, particularly brushes.

As shown in Fig. 1, a conventional flat motor 1
The bracket 4 is attracted by the magnetic force of the magnet 3 fixed to the cover 2, and current is passed through a pair of brushes 7 and 8 that contact a flat disk-shaped armature 6 in a housing 5 constituted by the cover 2 and the bracket 4. This allows the armature 6 to rotate. The armature 6 is made by bonding two flat copper plates punched (or printed, etc.) into a coil shape with an insulator in between, and joining the respective coiled parts at the periphery. A long coil circuit is formed.

This flat motor supplies power by directly contacting the brushes with the flat, disk-shaped, thin armature. This means that, compared to a normal magnet motor, which supplies power by contacting the brushes at right angles to the direction of the rotating shaft with an annular commutator attached around the rotating shaft, this flat motor has a structural problem in that noise is more likely to be generated at the contact surface between the armature and the brushes.

In such a flat motor 1, one of the brushes 7 and 8 has a positive pole and the other has a negative pole, and both of them are natural carbon brushes or metal-containing brushes (a natural carbon brush containing a conductive material such as Cu). However, in any case, both are made of the same material. This is based on the reason that it is desirable for the wear of both brushes to be uniform in terms of rotational balance and other aspects.

The characteristics of metal-containing brushes are that they have low electrical resistance, which increases the output of the motor, but they also generate a lot of noise when they come in contact with the armature.On the other hand, natural carbon brushes have a high resistance and low output, but generate less noise. . Therefore, both have advantages and disadvantages, and under the demand for uniform wear, it is necessary to sacrifice the advantages of one brush and adopt the same material for both brushes.

However, it has been found that completely uniform wear is not necessarily required in this flat motor, and even if the wear occurs somewhat slowly, there is no major difference in the timing of brush replacement between the two brushes.
This type of flat motor is often used in fan motors for air conditioners installed inside automobile cabins, and when used in such applications, there is a strong need to keep noise levels low. I have a request. Therefore,
Nowadays, more emphasis is placed on reducing motor noise and increasing motor output than on brush wear.

By the way, the collector ring (slip ring) of the generator
As shown in Japanese Patent Publication No. 37-5306, there is a known brush that uses a metal-containing brush for the negative electrode and a carbon brush for the positive electrode. In this case, the current collector ring that the copper-containing brush contacts is made of carbon, and the current collector ring that the carbon brush contacts is made of copper. In other words, the brush and current collector ring are always a combination of copper and carbon. The purpose is to prevent excessive wear of both the brush and current collector ring.

In view of the above-mentioned problems, the present invention was devised for the purpose of providing a flat motor that is superior in noise and output compared to conventional flat motors. As a result of various research based on conventional technology,
Flat motors that supply power by directly contacting brushes with the flat surface of a thin, flat disc-shaped armature not only tend to generate noise due to their structure, but also suffer from the flatness of the rotating flat disc-shaped armature in the rotating state. However, perhaps because it changes slightly depending on the rotation speed, the noise generated at the contact surface between the armature and the brush changes variously in various rotation ranges. Ordinary magnetic motors, which supply power by contacting the brushes to the motors, behave in ways that are completely unimaginable.Also, carbon brushes have low noise, while metal-containing carbon brushes have high noise. We have confirmed that this phenomenon exhibits phenomena that do not necessarily conform to common sense. In conventional flat motors that use brushes made of the same material for both poles,
In order to reduce noise in the rotation speed range, which is particularly problematic, we have discovered that this can be achieved by using a metal-containing brush on the cathode side and a carbon brush on the anode side, and have come to provide the present invention.

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

FIG. 2 is a longitudinal cross-sectional view showing the main parts of the flat motor according to the present invention, and the same members as in FIG. 1 are given the same reference numerals. This flat motor 10
In this example, the positive electrode brush 11 is a natural carbon brush, and the negative electrode brush 12 is a copper-containing brush.

Each brush is slidably inserted into a brush locker 13, and is pressed by a coil spring 14 with a predetermined pressure (approximately 150 g) toward the amateur side.

This brush locker 13 is attached to the cover 2 via a rubber holder 15. Conductive wires 16 and 17, commonly called pigtails, are fixed to each of the brushes 11 and 12, respectively, and these conductive wires 16 and 17 extend inside the housing 5, penetrate the cover 2, and protrude outside. A positive conductor wire 16 is connected to the natural carbon brush 11, and a negative conductor wire 17 is connected to the copper-containing brush 12.

When the brush noise characteristic, that is, the A characteristic (characteristic in which high and low frequencies are cut so that the sound is actually felt by the human ear) in the case of this configuration is measured, it will be as shown in FIG. 3.

In this figure, the solid line indicates the case of this example, in which a copper-containing brush is used for the negative electrode and a carbon brush is used for the positive electrode (abbreviated as −Cu+
C).

In addition, +Cu is used for the positive electrode using a copper-containing brush, and -C is used for the negative electrode.

According to the experimental results shown in Fig. 3, among the rotation speed ranges normally used in automobile air conditioners using flat motors, this example In the case of -Cu+C, the sound pressure level
It was found that the level (hereinafter referred to as SPL) was several dB lower than the others. In addition, at around 2000 rotations, compared to the -Cu+Cu case of the conventional example, the case of -Cu+C according to this embodiment is approximately 10 dB
It was also found that the SPL was low. Furthermore, according to this experimental result, the modulus in the case of -Cu+C according to this example is lower in SPL at the above-mentioned high rotation speed than in the case of -C+C, which was conventionally thought to have the lowest noise. There was found.

When the copper-containing brush 12 is used on the cathode side and the carbon brush 11 is used on the anode side (i.e. -
It is not necessarily clear why the SPL is the lowest at high rotational speeds in the case of Cu + C), but one reason may be that the flatness of the flat armature in the rotating state fluctuates depending on the rotational speed and remains constant. I think it's because they haven't. In addition, when considering the flow of electrons, it has been found through experiments that it is preferable to use a copper-containing brush on the cathode side from the viewpoint of sound countermeasures.

In addition, in terms of motor performance, since one of the brushes is a copper-containing brush, the electrical resistance is lower than when both brushes are made of natural carbon, resulting in improved motor output.

As is clear from the above explanation, according to the present invention, by connecting a copper-containing brush to the cathode side conductor and natural carbon to the anode side conductor, noise is significantly reduced in the rotation range where noise is a problem. In addition, the motor output is improved, and depending on the purpose of the motor, the generated noise and output can be easily tuned, which is an excellent effect.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a conventional flat motor, FIG. 2 is a longitudinal cross-sectional view of a main part of a flat motor according to the present invention, and FIG. 3 is a characteristic graph comparing the flat motor of the present invention with a conventional one. 2... Cover, 3... Magnet, 5... Housing, 6... Armature, 10... Flat motor, 11... Carbon brush, 12... Copper-containing brush, 16, 17... Conductor wire.

Claims (1)

[Scope of utility model registration request] A rotatable armature consisting of a flat disc-shaped copper coil fixed in a flat sealed housing and facing a magnet with a slight gap in between. A flat motor comprising at least a pair of brushes that are in direct contact with an armature plane, the brushes being composed of a copper-containing brush and a carbon brush, the copper-containing brush being a cathode-side conductor, and the carbon brush being an anode-side conductor. A flat motor that is connected to each conductor.