JPS6231977A - Electric contact - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Industrial Fields of Application The present invention is applicable to small motors used to drive tapes in tape recorders, video tape recorders, etc., as well as vertically movable contacts, slide switches, relays, connectors, etc. It relates to electrical contacts.

Conventional technology To explain this using an example of a small motor that has the highest number of contact openings and closings,
Generally speaking, there are two types of brushes used in small motors. One is to use elastic conductive materials such as copper, beryllium copper, copper-titanium alloys, phosphor bronze, and nickel silver Fi plates or wires with noble metal alloys (e.g., Au, Pd, Pt).
, Ag, Cu, etc., and their alloys) are clad or joined to a part of a thin plate or wire by spot welding, and the other is a part of the thin plate or wire mentioned above. Sintered carbon brushes (for example, carbon, Ag carbon, Cu carbon, AgCu carbon, and their materials such as SiC, M.

These brushes are formed by conductive adhesive, spot welding, caulking method, etc., but in small motors with these brushes, commutator During rotation, the brush sliding part vibrates unnecessarily, resulting in abnormal welding on the contact surface of the brush sliding part with the commutator segment, and blackening (carbon and carbon) caused by spark generation. A mixture of sliding wear particles generated between
This is a problem because foreign substances that promote abnormal phenomena often occur. An example of a brush for a small motor is one in which a brush sliding portion that comes into contact with 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 supporting 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.

For example, if the surface roughness of the commutator segment surface becomes rough due to wear, it will cause brush vibration, which will encourage the generation of electrical sparks, which will further progress wear and tear, causing abnormal wear, and electrical noise. The performance of the motor itself may deteriorate due to deviations in the commutation position.

Note that electric sparks are most often generated at the contact surface a of the brush sliding portion 3 with the commutator segment 4. Of course, it goes without saying that the commutator segment 4 and the brush sliding part 1, which are in contact with each other, also undergo mechanical wear that is not caused by electrical sparks.

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
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 5in2, and there is a risk of scratches.
In addition, as in the case of noble metal alloy brushes, the use of noble metal alloy carbon is an unfavorable combination in which scratches are likely to occur on the contact 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, welding and wear will occur, and the quality will be poor. In the example of FIG. 5(b), the brush sliding part 3
Figure 2 shows a configuration with vibration damping measures. 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, near the upper limit temperature of 60°C, the viscosity of the adhesive decreases significantly, and the adhesive force between the anti-vibration rubber 9 and the sliding part 3 decreases, resulting in a decrease in vibration absorption ability and increased occurrence of sparks. , it becomes difficult to obtain high-quality products with long lifespans. 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.Compared with the example shown in FIG. 5(b) above, Although the decrease in the viscosity of the adhesive at high temperatures can be suppressed to some extent, it is insufficient, and the long life at high temperatures is limited.
High quality cannot be satisfied.

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

The present invention prevents shortening of the life of electrical contacts in electrical connection structures such as vertical switches and relays with open/close contact structures, slide switches and connectors that have sliding contact structures similar to small motors, between the brush and commutator of motors, etc. It is something to do.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an electrical contact with an electrical connection structure such as a vertical movement switch or relay with an opening/closing contact structure, a slide switch with a sliding contact structure, or a connector. The atmosphere near the contact point is that of benzyl alcohol.

Effect: Previous literature and experiments have revealed the conditions in which the brush sliding part and the commutator segment tend to weld, or the conditions in which welding, abnormal wear, or poor guides 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 black matter (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) occurs. Promoting foreign matter is generated.

This foreign material is generated when unsaturated cyclic hydrocarbons are combusted by an arc between the sliding parts and the commutator segment.
This is thought to be due to the large amount of carbon per unit volume resulting in incomplete combustion and its molecular structure, but the bonding state of the produced carbon becomes dense, resulting in the formation of hard carbon.

In addition, in the atmosphere of hydrocarbons other than unsaturated cyclic hydrocarbons and adsorption to the commutator segment, i is
This is due to its molecular structure, but it has been clarified that the carbon produced is soft and does not lead to abnormal phenomena. Based on these phenomena, a long-term operation experiment was conducted using a commutator segment that adsorbed a small amount of 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 about 10 μg of unsaturated cyclic hydrocarbon is adsorbed on the commutator segment, abnormalities in the commutator segment will be alleviated and the life of the small motor will be extended. (However, this data is for the case where there is no continuous supply of unsaturated cyclic hydrocarbons.) The results were obtained.

Therefore, as a result of considering the above phenomenon, we found that when benzyl alcohol is used, unlike unsaturated cyclic hydrocarbons such as styrene monomers and toluene, it burns well because it has oxygen in its molecular structure, which causes abnormal phenomena. It is farthest away from the hard black-oxide formation, and even if carbon is formed, it is extremely soft and reduces the sliding resistance of the brush sliding part and the commutator segment.

In addition, this effect is due to the fact that an atmosphere suitable for the vapor pressure of benzyl alcohol can be created in the case even at high temperatures and low humidity where abnormal phenomena are likely to occur, and that the polar groups of benzyl alcohol have a strong effect on metal surfaces. Since it is adsorbed, sufficient effects can be obtained.

Further, good results can be obtained if the electrical contact in which benzyl alcohol is placed has a nearly hermetic structure with little air circulation, or if the device itself in which the electrical contact is installed has a structure with little air circulation.

By adsorption of benzyl alcohol, Au, 'Pd, Pt,
For example, commutator segments and brushes using materials with strong catalytic action such as Ag, etc. and their alloys, as well as those made of Cu etc., the surfaces of sintered carbon brushes, and other metals constituting the motor. It also adsorbs to the surface of parts, preventing highly reactive gases (styrene monomer, toluene, etc.) from adhering to the surface. this is,
This is because benzyl alcohol is more strongly adsorbed than organic gases, such as styrene monomers and toluene, which are absorbed by van der Waals attraction. The names of the drugs effective in the present invention and their properties are shown below.

Molecular formula: C6H5・CH,OH Boiling point: 205°C (1 atm) Melting point: 15°C (1 atm) Water absorption: 2% (40°C, 90% RH, 1 atm) It adsorbs to the segment surface, the electrical contacts of electrical connection structures such as vertical switches and relays with open/close contact structure, slide switches and connectors with sliding contact structure, and forms a monolayer film, which greatly improves lubricity. However, wear of the contact parts is also significantly reduced.

Embodiment FIGS. 1, 2 and 3 each show an embodiment in which the present invention is applied to a small motor. Here, parts with the same names as those in FIG. 4 are given the same reference numerals. In the figure, 7 is the bearing metal, 13 is the brush, 14
15 is a bracket for holding brushes, etc., 15 is under the motor case, 16 is felt impregnated with Hensyl alcohol, 17 is a magnet wire wrapped around the 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 placed near the brush sliding part 3 of the bracket 1, and in the embodiment shown in FIG. In the illustrated embodiment, the brush 13 is installed in a case 20 separate from the brush 13.

In addition, in each of the embodiments, the purpose is to make the atmosphere inside the case a vapor atmosphere caused by benzyl alcohol, and the benzyl alcohol is adsorbed onto the surfaces of the brush L brush and the commutator segment, but the means for achieving this are not limited to this. .

Figure 6 shows the results of the conventional product, Comparative Example 1) tested in a styrene monomer atmosphere, Comparative Example 2) tested in a toluene atmosphere, and the present invention tested in a benzyl alcohol atmosphere. .

Note that even if there are some impurities in the components of benzyl alcohol, benzyl alcohol still exhibits remarkable effects.

The results of the experiment shown in FIG. 6 in the example will be explained using the motor shown in FIG. 3. This motor is a DC motor with an outer diameter of 30mm.
The size is 25 mm in height, the rated output is 0, IW, and the operating conditions during the test are 4.2 VDC and 125 mA.

When a polyester felt 16 that had been cleaned and degreased with a polyfluoroethylene solution and impregnated with benzyl alcohol was installed in the gap of the motor, the benzyl alcohol gradually evaporated and a remarkable effect could be obtained. The evaporation speed of the polyester felt 16 can be controlled by changing the thickness and apparent specific gravity of its fibers. The polyester felt 16
Remarkable effects could also be obtained by using open-foamed plastic or rubber sponges instead. In addition, a sintered porous field magnet 19 impregnated with benzyl alcohol weighs 0.1 to 0.3 g.
It had a strong holding power and a remarkable effect could be obtained.

Furthermore, a product sealed in a gas-permeable film or case such as polyethylene and stacked in a small motor has the power to retain benzyl alcohol, and a remarkable effect could be obtained.

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

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

1) Benzyl alcohol adsorbs to the surface of the sliding part, which acts as a lubricant and has the effect of preventing abnormal wear and welding of the sliding contact surface and the resulting abrasion damage.

Table 1 shows an example of the results.

2) Even if there is an organic gas with a benzene ring such as styrene monomer or toluene, it is protected by a film of benzyl alcohol adsorbed on the surface of the sliding part, and the formation of black compounds is minimal, preventing contact failure between contacts. can. In addition, since there is no contact failure, electrical noise generation is also reduced.
For example, when used in a small motor, the speed is stabilized, and as a result, wow and flutter are reduced in equipment in which a small motor with a relatively low voltage of about 1 to 30 V is used. Table 1 shows an example of the results.

3) Due to the lubricating effect of benzyl alcohol, when a micromotor with an operating voltage of 1 to 30 mm and a current value of around 100 mA is operated in an atmosphere of benzyl alcohol, the current value decreases by 5 to 10%, resulting in energy savings.

Table 1 shows an example of the results.

4) Benzyl alcohol has a damping effect that suppresses vibrations generated by sliding motion, making it possible to reduce mechanical noise by 1 to IO%. Table 1 shows an example of the results.

5) The hygroscopicity of benzyl alcohol has an ideal balance between the hydrophilic 10H group and the hydrophobic 1C-C- (carbon bond), and it absorbs water even in an atmosphere of 40℃ and 90%RH. The ratio is 20% or less, and the lubricating effect is large without causing wetting to the extent that it corrodes the metal.
1. As a result of 1) to 5) above, the quality of the electrical contacts was improved and the life span was significantly extended.

[Brief explanation of drawings]

1 and 2 are block diagrams of an embodiment in which the present invention is applied to a small motor, FIG. 3 is a half-sectional view of a motor according to an embodiment of the present invention, and FIG. 4 is a general brush, Figures 5(a) to (C) are diagrams showing the configuration of a commutator, and Figures 5(a) to 5(C) are diagrams showing typical configurations of conventional brush sliding parts, respectively. Figures 6(a) to (d) are diagrams showing the effects of the present invention. It is a diagram showing the rectified waveform of the small motor that was confirmed. 3... Commutator sliding part, 4...
- Commutator segment, 16...Felt, 20...Motor case.

Claims (1)

[Claims] An electrical contact characterized by having a benzyl alcohol atmosphere inside the case containing the contact.