JPS62196042A - Small-sized motor - Google Patents

Abstract

PURPOSE:To prevent the life from being shortened by mechanical abrasion, by contactingly providing a member impregnated with hexamethyleneglycohol inside a motor case. CONSTITUTION:A small-sized motor is composed of a rotor core 18 wound with a magnet wire 17, a motor rotating shaft 6 and a field magnet 19 fixed to the interior of a motor case 20. This motor is equipped with a commutator segment 4, a brush 13 and a commutator pedestal 5. At this moment, with felt 16 impregnated with hexamethyleneglycohol and provided in a motor case 20, the hexamethyleneglycohol atmosphere is created inside the motor case 20. Thus, as the lubricating action works on the surface of the brush 13 and the segment 4, the abnormal abrasion of the slidingly contacted surface and the like can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a small motor used for driving a tape in, for example, a tape recorder or a video tape recorder.

To explain this using the example of a small morph that has the highest number of contact openings and closings in conventional technology,
Generally speaking, there are two types of brushes used in small motors. One is the use of elastic conductive materials such as copper, beryllium copper, copper titanium alloys, phosphor bronze, nickel silver thin sheets or wires, and precious metal alloys (such as Au, Pd, Pt,
The structure is made by cladding (Ag, Cu, etc. and their alloys) or by spot welding a part of the thin plate material or wire rod. Sintered carbon brush (e.g. carbon,
Ag carbon, Cu carbon, AgCu carbon, and SiC, M for those materials.

s2. These brushes are formed using conductive adhesive, spot welding, caulking method, etc. When the commutator rotates, in small motors with these brushes, The brush sliding part vibrates unnecessarily, which causes abnormal welding on the contact surface of the brush sliding part with the commutator segment, and blackening (carbon and other substances formed between the brush and the commutator segment) due to spark generation. This is a problem because foreign matter that promotes abnormal phenomena (mixed with shearing wear particles) is often generated. An example of a brush for a small motor is one in which a brush sliding portion that contacts a commutator segment is integrally formed with a brush base that is supported by support means provided on a lid of a motor case or the like. The state of contact between such a brush and the commutator segment is shown in FIG.

In FIG. 4, a bent brush sliding portion 3 extends from a brush base 2 supported by a brush support means 1. The brush base 2 and the brush sliding part themselves have elasticity and are in contact with the commutator segment 4 in a pressed state. This pressing force can be set to a required value by appropriately selecting the bending angle between the brush base 2 and the brush sliding portion 3. Further, 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 In this way, the commutator segments 4 that are in contact with each other
Electric sparks are generated from the brush sliding part 3 during rectification and due to intermittent contact points, and the generation of these electric sparks causes electrical noise, wear and welding of the commutator segment 4 and the brush sliding part 3. An inconvenient situation may occur, such as the occurrence of

For example, if welding occurs at the position where it starts to make contact with the commutator segment 4 and at the position where it leaves (section a in Fig. 4),
This welded material scrapes and damages the surface of the commutator segment 4, and furthermore, chips generated by this scraping accumulate in the gap between adjacent commutator segments 4 (section b in FIG. 4). Therefore, conduction occurs between the commutator segments, resulting in unstable rotation. In addition, for example, the surface roughness of the commutator segment surface may become rough due to wear and tear, which may cause brush vibrations and encourage the generation of electrical sparks, further progressing wear and tear, causing abnormal wear, or causing electrical noise. The performance of the motor itself may be deteriorated due to problems such as misalignment of the commutation position or deviation of the commutation position.

Incidentally, electric sparks are most often generated at the contact surface a between the brush sliding portion 3 and the commutator segment 4. Of course, the commutator segment 4
Needless to say, mechanical wear that is not caused by electric sparks also occurs in the brush sliding portion 3.

Generally, the material of the brush sliding part 3 that is often used is noble metal alloy or sintered carbon as mentioned above, and the material of the commutator segment 4 is Au, Pd, Ag.
Noble metal alloys such as AgCu, AgCd, AgCu
It consists of Cd, AgCuTi, etc. In particular, when used in combination with a noble metal brush, since both have high surface energy and are made of substantially the same material, this is an unfavorable combination that tends to cause abrasions on the contact surfaces. In addition, even when combined with a sintered carbon brush, although the sliding resistance is lower than that of a noble metal alloy brush, the blended materials that make up the brush contain a considerable amount of impurities such as Sin. There is a risk of abrasions, and as with noble metal alloy brushes, noble metal alloy carbon is an unfavorable combination that tends to cause abrasions on the mating surfaces. The example of FIG. 5(a) shows a structure without mechanical means to suppress the electrical sparks that cause these defects. That is, if no vibration damping measures are taken for the brush sliding part 3, the vibration of the brush sliding part will be large, sparks will be generated more often, and welding and wear will easily occur. The example in FIG. 5(b) shows a configuration in which vibration damping measures are taken for the brush sliding section 3. That is, vibration isolating rubber 9 is attached to brush sliding part 3 with adhesive 8, and vibration absorption is good at room temperature, and generation of sparks can be suppressed. However, the upper limit temperature for use is close to 60℃ (
In this case, the viscosity of the adhesive decreases significantly, the adhesive strength of the anti-vibration rubber 9 to the sliding part 3 decreases, the vibration absorption ability decreases, and more sparks are generated. becomes difficult to obtain. Furthermore, FIG. 5(C) is similar to FIG. 5(b).
Another example of a structure in which vibration damping measures are taken for the brush sliding part 3 in the same manner as in FIG. That is, a vibration isolating sheet 12 is attached to the brush sliding part 3 using an adhesive 11 having an adhesive 8 applied to both sides of a base material 10, as shown in FIG. 5(b) above.
Compared to the above example, although the decrease in the viscosity of the adhesive at high temperatures is suppressed to some extent, it is insufficient, and it is not possible to satisfy long life and high quality at high temperatures.

The ambient temperature for this device is -10°C to +60°C.
Many are used at ℃.

The present invention aims to prevent wear and tear of the brush and commutator caused by sliding between the motor brush and the commutator, abrasion damage due to welding, and shortening of motor life due to mechanical wear.

Means for Solving the Problems In order to solve the above problems, a brush base made of a thin plate-shaped or linear metal elastic body, and a brush base extending from the brush base or fixed to a part of the brush base are provided. In a small motor equipped with a brush having a brush sliding part, a part of the inside of the motor case, for example, near the brush sliding part on the bracket, is impregnated with hexamethylene glycol (hereinafter abbreviated as the chemical of the present invention). A member, such as felt, is attached using adhesive or pressure bonding.

In order to simplify the configuration of the motor, a configuration may be used in which the chemical of the present invention is directly applied to the brush or the brush sliding portion.

Taking the example of a small working motor, past literature and experiments are beginning to clarify the conditions in which brush sliding parts and commutator segments tend to weld, or conditions in which welding, abnormal wear, or poor continuity occur. Abnormalities are likely to occur in the atmosphere where the brush sliding portion and the commutator segment slide, or in the case where unsaturated cyclic hydrocarbons exist or are adsorbed in the commutator segment itself. At this time, an abnormal phenomenon called blackening is promoted (a mixture of decomposition products or carbon-like polymers produced by mechanochemical reactions, and sliding wear particles generated between the brush and the commutator segment). Foreign matter is generated.

This foreign material is caused by the fact that when unsaturated cyclic hydrocarbons are combusted by the arc between the sliding part and the commutator segment, the amount of carbon per unit volume is large, resulting in incomplete combustion, and the molecular structure of the unsaturated cyclic hydrocarbons. However, this is thought to be because the bonding state of the produced carbon becomes dense, resulting in hard carbon.

In addition, it was found that when hydrocarbons other than unsaturated cyclic hydrocarbons are adsorbed in the atmosphere and on the commutator segment, the carbon produced is soft and does not lead to abnormal phenomena, although this is due to its molecular structure. has been done. Based on these phenomena, a long-term operation experiment was conducted using a commutator segment of IT that had adsorbed hydrocarbons. In this experiment, we found that: 1) There is a high probability that abnormal wear will occur in the commutator segment under high temperature and low humidity.

2) If the commutator segment adsorbs about 10 μg of unsaturated cyclic hydrocarbons such as toluene, the abnormality of the commutator segment will be alleviated and the life of the small motor will be extended (however, unsaturated cyclic carbonization will continue to occur). Results were obtained (the data are for the case without hydrogen replenishment).

Therefore, as a result of considering the above phenomenon, it was found that when the chemical of the present invention is used, unlike styrene monomer or toluene, it has oxygen in its molecular structure, so it burns and becomes hard, which is the cause of abnormal phenomena. It is the furthest away from the formation of blackide, and even if carbon is formed, it is extremely soft and can reduce the sliding resistance of the brush sliding part and the commutator segment.

In addition, even at high temperatures and low humidity where abnormal phenomena are likely to occur, an appropriate atmosphere suitable for the vapor pressure of the chemical of the present invention can be created in the motor case, and the hydroxyl group of the chemical of the present invention can be applied to the metal surface. The chemical of the present invention is strongly adsorbed, so a sufficient effect can be obtained.In addition, the small motor in which the chemical of the present invention is placed has a nearly hermetic structure with little air circulation, or the equipment in which the small motor is installed itself is free from air. Better results can be obtained with structures that allow for less circulation.

In the adsorption of chemicals of the present invention, Au, Pd, Pt, Ag
, etc. and their alloys, as well as commutator segments and brushes made of materials with strong catalytic action, brushes made of Cu etc., surfaces of sintered carbon brushes, and surfaces of other metal parts constituting motors. It also adsorbs to the surface and prevents highly reactive gases (styrene monomer, toluene, etc.) from adhering to the surface. This is because the chemical of the present invention creates hydrogen bonds and adsorbs more strongly than organic gases, such as styrene monomers and toluene, which are adsorbed by van der Waals attraction. The substance name and properties of the drug of the present invention are as follows: Molecular formula: Hexamethylene glycol: C6HI□(OH) z Water absorption: 10% (40° C., 90% RH, 1 atm).

The aforementioned chemicals of the present invention are adsorbed to the surfaces of the brushes and commutator segments to form a monomolecular film, so lubricity is greatly improved and wear of the contact portions is significantly reduced.

Embodiment FIGS. 1, 2 and 3 each show an embodiment of the present invention. Here, parts with 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 that holds the brush 13, etc., 15 is under the motor case, 16 is a felt impregnated with the chemical of the present invention, and 17 is a magnet wire wrapped around a rotor core 18. , 19 is the motor case 20
It is a field magnet fixed to the inner surface of the

In the embodiment shown in FIG. 1, the felt 16 is placed near the brush sliding part 3 on the bracket 14, and
In the illustrated embodiment, a felt 16 is attached to the brush base 2. In 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. A brush sliding part may be provided, and the felt 16 may be mounted on the sliding part.

Further, in each of the embodiments, the atmosphere inside the motor case becomes a vapor atmosphere of the chemical of the present invention, so that the chemical of the present invention is adsorbed onto the surfaces of the brushes and commutator segments. Tests were conducted on the following comparative examples and examples.

Comparative example 1) Conventional product Comparative example 2) Test product in a styrene monomer atmosphere Comparative example 3) Test product in a toluene atmosphere Example 1)
The results of test products in a chemical atmosphere of the present invention are shown.

Furthermore, even if there are some impurities in the ingredients of the drug of the present invention,
The drug of the present invention exhibited remarkable effects.The results of the test are shown in the following table.

The motor used in the margin test will be explained below using the motor shown in FIG. This motor is a DC motor, has an outer diameter of 30 mm, a height of 25 mm, a rated output of 0.1 W, and the operating conditions at the time of the test were 4.
2VDC 125mA.

If a polyester felt 16 that has been cleaned and degreased with a polyfluoroethylene solution is impregnated with the chemical of the present invention in the gap of the motor, the chemical of the present invention will gradually evaporate and a remarkable effect will be obtained. was completed. The evaporation speed of the polyester felt 16 can be controlled by changing the thickness and apparent specific gravity of its fibers. Remarkable effects could also be obtained by using open-cell foamed plastic or rubber sponge instead of the polyester felt 16.

In addition, a sintered porous field magnet 19
impregnated with the chemical of the present invention.
It had a holding force of 3g and a remarkable effect could be obtained. In addition, in the same way, one blended into the plastic bracket 14, one blended into the plastic commutator base 5, one impregnated into the magnet wire 17, one blended into the oil of the metal of the bearing metal 7, A material impregnated into the gap between the magnet 19 and the motor case 20, a material blended with the anti-vibration rubber 9, a material blended with the anti-vibration rubber pasting adhesive 8 shown in FIG. 5, and a gas permeable film such as polyethylene. Alternatively, a device sealed in a case and installed inside a small motor also had the ability to retain the chemical of the present invention, and a remarkable effect could be obtained.

Furthermore, since the chemical of the present invention is solid at room temperature, it is necessary to raise the temperature to the melting point when impregnating parts, but it can be easily used by dissolving it in 2-methyl-2,4-pentanediol, which has a similar effect. It was possible to impregnate it and obtain remarkable effects.

Figure 6 shows the rectification waveform of the small motor of the present invention. ) is the rectified waveform before the test in an unsaturated cyclic hydrocarbon styrene monomer atmosphere at 60°C and 5% RH and
The rectification waveform (c) of Comparative Example 2 after the 00 hour test is the rectification waveform before the 60°C, 5% RH atmosphere test when approximately 10 μg of unsaturated cyclic hydrocarbon (toluene) is adsorbed on the commutator segment surface, and the rectification waveform (c) before the 60°C, 5% RH atmosphere test.
The rectification waveform (d) of Comparative Example 3 after the 0-hour test shows the rectification waveform before the 60° C., 5% atmosphere test in the chemical atmosphere of the present invention, and the rectification waveform of Example 1 after the 1500-hour test.

Effects of the Invention As is clear from the above description, the present invention provides the following effects.

1) By adsorbing the chemicals of the present invention to the surfaces of the brushes and commutator segments, a lubricating effect is exerted, which has the effect of preventing abnormal wear and welding of the contact surfaces and the resulting abrasion damage.

2) Even if there is an organic gas having a benzene ring such as styrene monomer or toluene, it will be protected by the film of the chemical of the present invention adsorbed onto the surface of the brush, commutator segment, and the formation of blackened particles will be minimal. It is possible to prevent the occurrence of poor contact between the two. In addition, since contact failure does not occur, the generation of electrical noise is also reduced, and the speed of small motors is stabilized.
To reduce wow and flutter in equipment in which a small motor for relatively low voltage is used.

3) Due to the lubricating effect of the chemical of the present invention, when a commonly used micromotor with an operating voltage of 1 to 30 V and a current value of around 100 mA is operated in an atmosphere of the chemical of the present invention, the current value decreases by 5 to 10%. Energy saving can be achieved.

4) The chemical of the present invention has a damping effect that suppresses vibrations generated by the sliding movement of the brush and the commutator;
Allows for ~10% reduction in mechanical noise. In other words, it has almost the same noise-damping effect as the vibration-proof rubber normally attached to brushes.

5) The hygroscopic property of the chemical of the present invention is that it has hydrophilicity -OH
The balance between the group and the hydrophobic 1C-C- (carbon bond) is ideal, and even in an atmosphere of 40℃ and 90%RH, the water absorption rate is less than 20%, making it so wet that it corrodes metal. This results in a large lubrication effect.

6) When the chemical of the present invention is dissolved in 2-methyl-2,4-pentanediol for a few months, it can be impregnated into parts at room temperature, resulting in excellent productivity and long effect duration.

[Brief explanation 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. 4 is a diagram showing the configuration of a general brush and a commutator. Fifth
Figures (a) to (c) each show a typical configuration of a conventional brush sliding section, and Fig. 6 is a diagram showing a rectified waveform of a small motor according to the present invention. 3... Commutator sliding part, 4...
- Commutator segment, 14...Bracket, 16...Felt, 20...Motor case. Name of agent: Patent attorney Toshio Nakao Haka1/6---
7 Elt Invasion Figure 2 Li3 Figure 3 Figure 4 Figure 5

Claims (2)

[Claims] (1) In a small motor that has a brush mechanism and a commutator, and has a structure in which the brush and the commutator slide,
A small motor characterized by having a hexamethylene glycol atmosphere inside the motor case. (2) Hexamethylene glycol is 2-methyl-2,
The small motor according to claim 1, characterized in that it is used after being dissolved in 4-pentanediol.