JPH0728517B2 - Small motor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small motor used for driving a tape of, for example, a tape recorder / video tape recorder.

Conventional technology Explaining with an example of a small motor with the highest number of contacts,
Generally, there are two types of brushes in a small motor. One is a conductive material with elasticity, such as copper.
Beryllium copper, copper-titanium alloy, phosphor bronze, nickel-white thin plate material or wire material with noble metal alloy (eg Au, Pd, Pt, Ag, Cu, etc.) clad, or thin plate material, part of wire material Is a structure that is joined by means of spot welding to another, and the other is a sintered carbon brush (for example, carbon, Ag carbon, Cu carbon, AgCu carbon, and their Si as material
C, MoS ₂ , Pb, epoxy resin, etc. are added as additives) by means of conductive adhesive, spot welding, or caulking method. When the commutator rotates, the brush sliding part vibrates unnecessarily, which causes abnormal welding on the contact surface of the brush sliding part with respect to the commutator segment, and the black matter (carbon and brush and commutator due to spark generation). -It often becomes a problem that foreign matter is generated that promotes an abnormal phenomenon called "a mixture of sliding wear particles generated between segments". As an example of a brush for a small motor, there is one in which a brush sliding portion that makes contact with a commutator segment is integrally formed with a brush base portion that is supported by a supporting means provided on a lid of a motor case. The contact state between such a brush and the commutator segment is shown in FIG.

In FIG. 4, a folded brush sliding portion 3 extends from a brush base portion 2 supported by a brush supporting means 1. The brush base portion 2 and the brush sliding portion itself have elasticity and are in contact with the commutator segment 4 in a pressed state. Then, this pressing force can be set to a required value by appropriately selecting the bending angle between the brush base portion 2 and the brush sliding portion 3. The commutator segment 4 is fixed to the motor rotating shaft 6 via the commutator base 5 and rotates with the rotation of the motor.

Problems to be Solved by the Invention As described above, the commutator segment 4 which is in contact with each other
An electric spark is generated from the brush sliding part 3 at the time of rectification and due to an intermittent contact point. With the generation of the electric spark, electrical noise, wear and welding on the commutator segment 4 and the brush sliding part 3 are caused. An inconvenient state occurs such as occurrence of.

For example, when welding occurs at the position where the commutator segment 4 starts to contact and the position where the commutator segment 4 starts to separate (part a in FIG. 4)
This welded material rubs the surface of the commutator segment 4 to cause damage, and the chips generated by this rubbing are accumulated in the gap portion (b portion in FIG. 4) between the commutator segments 4 adjacent to each other, Therefore, the commutator and the segment are electrically connected to each other, and the rotation becomes unstable.

Also, for example, if the surface roughness of the commutator segment surface becomes rough due to wear, it will cause vibration of the brush, which will promote the generation of electric sparks, further wear and wear, and cause abnormal wear. The performance of the motor itself will be degraded, such as the displacement of the commutation position.

It should be noted that the electric spark is best generated at the contact surface a with the brush sliding part 3 and the commutator segment 4. Needless to say, the commutator segment 4 and the brush sliding portion 3 that come into contact with each other also suffer mechanical wear that is not caused by electric sparks.

Generally, the material of the brush sliding part 3 that is often used is a noble metal alloy or sintered carbon as described above, and the material of the commutator segment 4 is a noble metal alloy such as Au, Pd, Ag (eg AgCu, AgCd, AgCuCd). , AgCuTi, etc.). In particular, the combination with a noble metal brush is a disadvantageous combination in which the surface energy is high and the both are substantially the same material, and thus scratches are likely to occur on the contact surface. In addition, even in the combination with a sintered carbon brush, although the sliding resistance is smaller than that of a noble metal alloy brush, impurities such as SiO ₂ are not a little mixed in the blended material forming the brush, There is a risk of scratches, and as with noble metal alloy brushes, noble metal alloy carbon forms an unfavorable combination in which scratches easily occur on the contact surface. Fig. 5 (a)
Example of the electric sparks that are responsible for these shortcomings,
6 shows a structure without mechanical means of restraining. That is, in the case where no vibration damping measures are taken in the brush sliding part 3, the vibration of the brush sliding part is large, the number of sparks is increased, and welding and wear are likely to occur.

The example of FIG. 5 (b) shows a structure in which the brush sliding portion 3 is provided with vibration damping measures. That is, the vibration-proof rubber 9 is attached to the brush sliding part 3 with the adhesive 8. The vibration absorption is good at room temperature and the generation of sparks can be suppressed. However, in the vicinity of the maximum use temperature of 60 ° C, the viscosity of the pressure-sensitive adhesive decreases remarkably, the adhesive strength of the anti-vibration rubber 9 with the sliding portion 3 decreases, the vibration absorption capacity decreases, and sparks increase. However, it is difficult to obtain a good product with a long life.
Further, FIG. 5 (c) shows another example of the structure in which the brush sliding portion 3 is provided with vibration damping measures as in FIG. 5 (b). That is, the vibration-proof sheet 12 is attached to the brush sliding portion 3 with the adhesive 11 having the structure in which the pressure sensitive adhesive 8 is applied to both sides of the base material 10. Compared with the example of FIG. 5 (b), Although the decrease in the viscosity of the pressure-sensitive adhesive at high temperature can be suppressed to some extent, it is insufficient, and it is not possible to satisfy the long life and high quality at high temperature.

The ambient temperature of this equipment is often -10 ℃ to + 60 ℃.

The present invention is intended to prevent wear of the brush commutator caused by sliding of the brush of the motor and the commutator, and short-circuiting of the motor life due to abrasion damage due to welding and mechanical wear.

Means for Solving the Problems In order to solve the problems, a brush base made of a thin plate material or a linear metal elastic body, and extending from the brush base, or fixed to a part of the brush base. In a small motor provided with a brush having a brush sliding part, a member impregnated with 7-mentanol, for example, a felt is fixed with an adhesive in a part of the motor case, for example, in the vicinity of the brush sliding part on the bracket. It is installed by means such as a crimping method.

This 7-mentanol turns into steam depending on the ambient temperature,
The inside of the motor case is configured to have an atmosphere of 7-mentanol. In addition, in order to simplify the motor configuration, a configuration may be used in which the 7-mentanol is directly applied to the brush or the brush sliding portion.

Action The state in which the brush sliding part and the commutator segment are easily welded, or the state in which welding, abnormal wear, and poor conduction are likely to occur is being clarified in the literature and experiments so far. Abnormality is likely to occur in the atmosphere where the sliding parts of the brush and commutator segment slide.
Or it is the case where unsaturated cyclic hydrocarbons are present or adsorbed in the commutator segment itself. At this time, a foreign substance that promotes an abnormal phenomenon called a black matter (a carbon-like substance that is a decomposition product or a polymer formed by a mechanochemical reaction and a substance that is mixed with sliding wear particles generated between the brush and the commutator segment). Is generated.

This foreign matter is due to the fact that when unsaturated cyclic hydrocarbons are burned by the arc between the sliding part and the commutator segment, they have a large amount of carbon per unit volume and incompletely burn, and also due to their molecular structure. However, it seems that hard carbon is formed because the bonded state of the generated carbon becomes dense.

Also, in the adsorption of hydrocarbons other than unsaturated cyclic hydrocarbons and adsorption to commutator segments, it is due to the molecular structure, but the generated carbon becomes soft, which does not lead to abnormal phenomena. Has been done. Based on these phenomena, a long-term operation experiment was conducted using a commutator segment in which a very small amount of hydrocarbon was adsorbed. In this experiment, 1) there is a high probability that abnormal wear will occur in the commutator segment in the case of high temperature and low humidity.

2) When the commutator segment has adsorbed about 10 μg of unsaturated cyclic hydrocarbon such as toluene, the abnormality of the commutator segment is mitigated, and the life of the small motor can be extended (however, continuous unsaturated cyclic carbonization does not occur). The results were obtained, which is the data without hydrogen replenishment.

Therefore, as a result of considering the above phenomenon, when 7-mentanol is used, it burns well because it has oxygen in its molecular structure unlike styrene monomer and toluene, and hard black oxide formation, which is one of the abnormal phenomena, is generated. It becomes the furthest existence, and becomes extremely soft even if carbon is generated, reducing the sliding resistance of the brush sliding part and commutator segment.

Also, this effect is that, for example, even at high temperature and low humidity where an abnormal phenomenon is likely to occur, an atmosphere matching the vapor pressure of 7-mentanol can be obtained in the motor case, and the polar group of 7-mentanol causes the metal surface on the metal surface. Since it strongly adsorbs, a sufficient effect can be obtained.

In addition, a small motor with 7-mentanol placed has a structure close to airtight with almost no air circulation, or a device in which the small motor is installed has a structure with little air circulation, which gives better results. .

7 Not only commutator segments and brushes made of materials with strong catalytic action such as Au, Pd, Pt, Ag, etc. and their alloys by adsorption of menthanol, those made of Cu, etc., surface of sintered carbon brush , And other metal components constituting the motor are also adsorbed to the surface to prevent highly reactive gas (styrene monomer, toluene, etc.) from adhering to the surface. This is because 7-Mentanol is more strongly adsorbed than the organic gas adsorbed by van der Waals attraction such as styrene monomer and toluene. The substance names and properties of drugs effective in the present invention are shown below.

Molecular formula: C ₆ H ₉ (CH ₂ OH) (iC ₃ H ₇ ) Molecular structure: Boiling point: 236 ° C (1 atm) Melting point: 20 ° C (1 atm) Water absorption rate: 0% (40 ° C, 90% RH, 1 atm) The above 7-mentanol is adsorbed on the brush, commutator segment surface and Since the molecular film is formed, the lubricity is extremely improved, and the wear of the contact portion is significantly reduced.

Embodiment FIG. 1, FIG. 2 and FIG. 3 each show an embodiment of the present invention. Here, parts having the same names as those in FIG. 4 are given the same reference numerals. In the figure, 7 is a bearing metal, 13 is a brush, 14 is a bracket for holding the brush 13, etc., 15 is a motor case, 16 is a felt impregnated with 7-mentanol, 17 is a magnet wire wound around a rotor core 18, 19 Is a field magnet fixed to the inner surface of the motor case 20. In the embodiment shown in FIG. 1, the felt 16 is arranged on the bracket 14 in the vicinity of the brush sliding portion 3, and in the embodiment shown in FIG.
A felt 16 is attached on the upper side, and in the embodiment shown in FIG. 3, the felt 16 is mounted on the motor case 20 apart from the brush 13. In each of the embodiments shown in FIGS. 1 and 2, the brush sliding part 3 made of a carbon brush is fixed to the tip of the brush base 2, but the brush base 2 is bent and extended. A brush sliding part may be provided, and the felt 16 may be mounted on the sliding part.

Further, in any of the examples, the atmosphere inside the motor case is 7
The purpose is to create a vapor atmosphere with mentanol and to adsorb 7-mentanol on the surface of the brush and commutator segment. The means is not limited to this.

FIG. 6 shows the results of the conventional product, the test product in the styrene monomer atmosphere of Comparative Example 1), the test product in the toluene atmosphere of Comparative Example 2), and the test product in the 7-mentanol atmosphere of the present invention. .

It should be noted that even if the 7-mentanol component has some impurities, 7-mentanol exhibits a remarkable effect.

The results of the experiment of FIG. 6 in the embodiment will be described with the motor of FIG. This motor is a DC motor with an outer diameter of 30 mm and a height of
25mm size, rated output 0.1W, operating conditions during the test are 4.
It is 2VDC, 25mA.

When the polyester felt 16 was washed with a polyfluoroethylene solution and degreased in the air gap of this motor, and the one impregnated with 7-mentanol was installed, the 7-mentanol was gradually evaporated and a remarkable effect could be obtained. The polyester felt 16 can control the evaporation speed by changing the fiber thickness and the apparent specific gravity. Even if a continuous foamed plastic or rubber sponge was used instead of the polyester felt 16, a remarkable effect could be obtained. Further, the sintered porous field magnet 19 impregnated with 7-mentanol had a holding force of 0.1 to 0.3 g, and a remarkable effect could be obtained. Also, similarly, those blended with the plastic bracket 14, blended with the plastic commutator base 5, impregnated with the magnet wire 17, blended with the oil of the bearing metal 7, Impregnated into the gap between the magnet 19 and the motor case 20, blended with the anti-vibration rubber 9,
The one blended with the anti-vibration rubber sticking adhesive 8 shown in FIG. 5 and the one enclosed in a gas permeable film such as polyethylene or a case and installed in a small motor also have the ability to retain 7-mentanol, which is a remarkable effect. I was able to get

In addition, in FIG. 6, (a) shows a rectified waveform of a conventional product before the test in a 5% RH atmosphere at 60 ° C. and a rectified waveform after the 300-hour test, and (b) shows an unsaturated cyclic hydrocarbon styrene. The rectification waveform before the test at 60 ° C., 5% RH in a monomer atmosphere and the rectification waveform of Comparative Example 1 after the 100-hour test are shown. (C) shows unsaturated cyclic hydrocarbon (toluene) on the commutator segment surface. The rectified waveform before 60 ° C., 5% RH atmosphere test and the rectified waveform of Comparative Example 2 after 300 hours test when about 10 μg was adsorbed, and (d)
Is 60 ° C. in the benzyl alcohol atmosphere of the present invention, 5
% The rectified waveform before the atmosphere test and the rectified waveform after the 1500-hour test are shown.

EFFECTS OF THE INVENTION As is apparent from the above description, the present invention has the following effects.

1) Adsorption of 7-Mentanol to the surface of brush and commutator segment has a lubricating effect, and has an effect of preventing abnormal wear and welding of the contact surface and abrasion and damage thereof. Table 1 shows an example of the result.

2) Even if there is an organic gas having a benzene ring such as styrene monomer or toluene, it is protected by a film of 7-mentanol adsorbed on the brush, commutator segment surface,
The generation of black matter is also small, and it is possible to prevent the occurrence of poor contact between the brush, commutator and segment. In addition, because contact failure does not occur, the generation of electrical noise is reduced, the speed of a small motor is stabilized, and as a result, 1-30V
Wow and flutter of equipment that uses a small motor for relatively low voltage is reduced. Table 1 shows an example of the result.

3) When a micromotor with a working voltage of 1 to 30 V and a current value of about 100 mA, which is commonly used due to the lubricating action of 7-Mentanol, is operated in an atmosphere of 7-Mentanol, the current value decreases by 5-10%, which saves energy. . Table 1 shows an example of the result.

4) 7-Mentanol has a damping effect to suppress the vibration generated by the sliding motion of the brush and commutator,
Enables reduction of mechanical noise of 1-10%. That is, it has almost the same sound deadening effect as the anti-vibration rubber normally attached to the brush. Table 1 shows an example of the result.

5) As for the hygroscopicity of 7-menthol, the ideal balance is between hydrophilic -OH group and hydrophobic -CC- (carbon bond), and it absorbs water even in an atmosphere of 40 ° C and 90% RH. The ratio is 20% or less, and the lubricating effect is large without being wet enough to corrode the metal.

As a result of the above 1) to 5), the quality of the small motor was improved and the life could be significantly extended.

[Brief description of drawings]

1 and 2 are configuration diagrams of an embodiment of the present invention, FIG. 3 is a half sectional view of a motor of an embodiment of the present invention, and FIG.
FIG. 5 is a diagram showing the configuration of a general brush and commutator, FIGS. 5 (a) to 5 (c) are diagrams showing a typical configuration of a brush sliding portion of a conventional example, and FIGS. 6 (a) to 6 (d). [Fig. 4] is a diagram showing commutation waveforms of small motors in a conventional example, a comparative example, and an example of the present invention. 3 …… Commutator sliding part, 4 …… Commutator ・
Segment, 14 …… Bracket, 16 …… Felt, 20…
… Motor case.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeru Kondo 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP 62-31975 (JP, A) JP 59-6381 (JP, A)

Claims (1)

[Claims] 1. A small motor having a brush mechanism section and a commutator, wherein the brush and the commutator slide, wherein the motor case has an atmosphere of 7 mentanol.