JPH0748328B2 - Electrical contact - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an up-and-down moving contact, for example, between a brush commutator of a small motor used for driving a tape of a tape recorder, a video tape recorder, etc.
It relates to electrical contacts such as slide switches and relays.

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 having elasticity, for example, copper, beryllium copper, copper titanium alloy, phosphor bronze, nickel silver thin plate material or wire material, and precious metal alloys (for example, Au, Pd, Pt, Ag, Cu, etc. and their alloys). ) Is clad or joined to a part of a thin plate material or a wire material by means of spot welding,
The other is a sintered carbon brush (eg carbon, Ag carbon, Cu
SiC, Mo for carbon, AgCu carbon, and their materials
S _2, Pb, those formulated as an additive and epoxy resin) of a conductive adhesive, spot welding, or are formed by means such as caulking method, in the small-sized motor having these brushes, commutator During rotation, 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 black matter (carbon and brush and commutator segment) 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 during the operation. 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 may cause vibration of the brush,
It promotes the generation of electric sparks, promotes further consumption, causes abnormal wear, and reduces the motor performance itself, such as electrical noise and deviation 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.). Especially when combined with precious metal brushes,
Since the surface energy is high and both materials are almost the same, it is a disadvantageous combination in which scratches easily occur on the contact surface. In addition, even when combined 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 carbon, which is a precious metal alloy as in the case of precious metal alloy brushes, is a disadvantageous combination in which scratches are likely to occur on the contact surface. The example of FIG. 5 (a) shows a structure that does not have a mechanical means for suppressing the electric sparks that are the cause of these drawbacks. 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 portion 3 with the adhesive 8, and 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 and the adhesive 8
Is adhered with an adhesive material 11 having a composition coated with, and compared with the example of FIG. 5 (b), the decrease in the viscosity of the adhesive at high temperature can be suppressed to some extent, but is insufficient.
Long life at high temperature and high quality cannot be satisfied.

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

The present invention prevents the shortening of the electrical contact life of an electrical connection structure such as an up / down switch having a switching contact structure, a relay, or a brush / commutator of a motor, a slide switch having a sliding contact structure like a small motor, and a connector. To do.

Means for Solving the Problems In order to solve the above problems, the present invention relates to a vertical movement switch having a switching contact structure, a relay, or a slide switch having a sliding contact structure, a machine for a brush / commutator in a small motor, and the like. In the electrical contact having a structure in which the contacts are separated from each other, the atmosphere is made to be an atmosphere of isopropylbenzyl alcohol in the vicinity of the contact or in the case of a substantially sealed structure in which the contact is built.

Actions Explaining with an example of a small motor, the state in which the brush sliding part and the commutator segment are easily welded, or the state in which welding, abnormal wear, and conduction failure are likely to occur is being clarified in the literature and experiments so far. An abnormal state is likely to occur when the brush sliding part and the commutator segment slide in the atmosphere or when the commutator segment itself contains or adsorbs unsaturated cyclic hydrocarbons. At this time, an abnormal phenomenon called black matter (decomposition product, carbon-like polymer that is a polymer formed by mechanochemical reaction, and mixture of sliding wear powder generated between brush and commutator segment) is generated. Foreign matter that promotes is generated.

This foreign matter is generated when unsaturated cyclic hydrocarbons are burned by the arc between the sliding part and the commutator segment.
This is due to the fact that a large amount of carbon per unit volume results in incomplete combustion and the molecular structure thereof, but because the binding state of the produced carbon becomes dense, hard carbon can be formed.

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 approximately 10 μg of unsaturated cyclic hydrocarbon is adsorbed on the commutator segment, the abnormality of the commutator segment is alleviated and the life of the small motor is extended. The results were obtained (however, the data were obtained when there was no continuous supplement of unsaturated cyclic hydrocarbon).

Therefore, as a result of considering the above phenomenon, when isopropylbenzyl alcohol is used, unlike unsaturated cyclic hydrocarbons such as styrene monomer and toluene, it has oxygen in its molecular structure and thus burns well, causing abnormal phenomena. It is farthest from the formation of hard black matter, which is one, and becomes extremely soft even if carbon is produced, reducing the sliding resistance of the brush sliding part and commutator segment.

In addition, this effect is that the atmosphere matching the vapor pressure of isopropylbenzyl alcohol can be obtained in the case even at high temperature and low humidity where an abnormal phenomenon is highly likely to occur, and the polar group of isopropylbenzyl alcohol causes the metal surface on the metal surface. Since it strongly adsorbs, a sufficient effect can be obtained.

Also, the electrical contact to be placed in the atmosphere of isopropylbenzyl alcohol has a structure close to the airtight with almost no air circulation, or the device itself in which the electrical contact is incorporated has a structure with little air circulation. can get.

By adsorption of isopropylbenzyl alcohol, Au, Pd, Pt, A
g, etc. and its alloys with strong catalytic action, for example, commutator segment and brush, of course, made of Cu, surface of sintered carbon brush,
Also, it is adsorbed on the surface of other metal parts that compose the motor and highly reactive gas (styrene monomer,
Toluene, etc.) is prevented from adhering. This is because isopropylbenzyl alcohol is more strongly adsorbed than the organic gas adsorbed by the van der Waals attraction such as styrene monomer and toluene. The molecular structure and properties of isopropylbenzyl alcohol effective in the present invention are shown below.

Molecular formula: C ₆ H ₄ (CH ₂ OH) (iC ₃ H ₇ ) Boiling point: 246 ° C (1 atm) Melting point: 28 ° C (1 atm) Water absorption: 0% (40 ° C ・ 90% RH ・ 1 atm) The above-mentioned isopropylbenzyl alcohol is a brush, commutator segment surface, switching contact structure. The vertical movement switch, relay, or sliding switch with sliding contact structure, and the electrical contact of the electrical connection structure such as the connector are adsorbed to form a monomolecular film, so the lubricity is extremely improved and the contact part wears. Is also significantly reduced.

90% or more of the isopropylbenzyl alcohol
The chemical that is 1,4-isopropylbenzyl alcohol has no unpleasant odor even if the case of the electrical contact is not completely sealed and can be used without any practical problems. When the purity of 1,4-isopropylbenzyl alcohol is 90% or less, it has an unpleasant odor, and when the odor becomes a problem, it is difficult to use.

Embodiment FIG. 1, FIG. 2 and FIG. 3 show an embodiment when the present invention is applied to a small motor. 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, 15 is under the motor case,
Reference numeral 16 is a felt impregnated with isopropylbenzyl alcohol, 17 is a magnet wire wound around a rotor core 18, and 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. 2, the felt 16 is placed on the brush base 2.
16 is attached, and in the embodiment of FIG. 3, it is mounted on the case 20 apart from the brush 13.

Further, in all of the examples, the atmosphere in the case is changed to a vapor atmosphere by isopropylbenzyl alcohol so that isopropylbenzyl alcohol is adsorbed on the surface of the brush and the commutator segment, and the means is not limited to this. .

FIG. 6 shows the results of the conventional product, the test product in Comparative Example 1) in a styrene monomer atmosphere, the test product in Comparative Example 2) in a toluene atmosphere, and the test product in the isopropylbenzyl alcohol atmosphere of the present invention. Show.

In addition, even if the component of isopropylbenzyl alcohol has some impurities, isopropylbenzyl alcohol exerts a remarkable effect.

90% or more of the isopropylbenzyl alcohol
The chemical that is 1,4-isopropylbenzyl alcohol has no unpleasant odor even if the case of the electrical contact is not completely sealed and can be used without any practical problems.

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, the outer die is 30mm high
25mm size, rated output 0.1W, operating conditions during the test are 4.
It is 2VDC, 25mA.

In this motor, polyester felt 16 washed with polyfluoroethylene liquid and degreased, and impregnated with isopropylbenzyl alcohol were installed in the air gap of this motor. It was 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.

In addition, the sintered porous field magnet 19 impregnated with isopropylbenzyl alcohol is 0.
It had a holding power of 1 to 0.3g and was able to obtain a remarkable effect.

Also, a gas-permeable film such as polyethylene or a case enclosed in a case and installed in a small motor has a force to hold isopropylbenzyl alcohol, and a remarkable effect can be obtained.

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. (C) shows the rectified waveform in a monomer atmosphere before 60 ° C., 5% RH atmosphere test and the rectified waveform in Comparative Example 1 after 100 hours test (c) shows unsaturated cyclic hydrocarbon (toluene) on the commutator segment surface 6 shows the rectified waveform before 60 ° C., 5% RH atmosphere test when adsorbed 10 μg and the rectified waveform of Comparative Example 2 after 300 hours test, and (d) shows 60 ° C. in the isopropylbenzyl alcohol atmosphere of the present invention, % 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 isopropylbenzyl alcohol to the sliding surface has a lubricating effect, and is effective in preventing abnormal wear and welding of the sliding contact surface and abrasion and damage caused thereby. Table 1 shows an example of the result.

2) Even if there is a benzene ring-containing organic gas such as styrene monomer or toluene, it is protected by the film of isopropylbenzyl alcohol adsorbed on the sliding surface, and the generation of black matter is minimal, resulting in poor contact between contacts. It can be prevented. In addition, since it does not cause contact failure, it also reduces the generation of electrical noise and stabilizes the speed when used in small motors, for example, resulting in a small size for relatively low voltage of 1 to 30V. Reduces wow and flutter in equipment where motors are used. Table 1 shows an example of the result.

3) Due to the lubricating action of isopropylbenzyl alcohol, for example, when operating a micromotor with an operating voltage of 1 to 30 V and a current value of around 100 mA in an isopropylbenzyl alcohol atmosphere, the current value decreases by 5 to 10% and energy saving can be achieved. . Table 1 shows an example of the result.

4) Isopropylbenzyl alcohol has a damping effect that suppresses vibration caused by sliding, and is 1-10%.
It is possible to reduce the mechanical noise of. Table 1 shows an example of the result.

5) The hygroscopicity of isopropylbenzyl alcohol is ideally balanced between the hydrophilic -OH group and the hydrophobic -CC- (carbon bond), and absorbs water even in an atmosphere of 40 ° C and humidity of 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 electrical contact was improved and the life could be significantly extended.

6) 90% of the isopropylbenzyl alcohol
The above-mentioned chemical which is 1,4-isopropylbenzyl alcohol has no unpleasant odor even when the case of the electrical contact is not completely sealed and can be used without any practical problems.

As a result of the above 1) to 6), the quality of the electrical contact was improved and the life could be significantly extended.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are configuration diagrams of an embodiment when the present invention is applied to a small motor, and FIG. 3 is a half sectional view of a motor of the 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 a small motor in various atmospheres. 3 …… Commutator sliding part, 4 …… Commutator ・
Segment, 16 …… felt, 20 …… motor case.

Claims (2)

[Claims] 1. An electrical contact characterized in that an atmosphere of isopropylbenzyl alcohol is provided in a case having a substantially hermetically-sealed structure having a contact for mechanically contacting and separating. 2. The electrical contact according to claim 1, wherein the isopropylbenzyl alcohol is 90% or more of para-isopropylbenzyl alcohol (1,4-isopropylbenzyl alcohol).