JPS62196044A - Electrical contacts - Google Patents

Abstract

PURPOSE:To prevent the life of electrical contacts from being shortened, by providing a member impregnated with 2-ethyl-1,3-hexandiol in a case equipped with the electrical contacts. CONSTITUTION:A small-sized motor is composed of a rotor core 18 secured to a rotating shaft 6 and a field magnet 19 fixed to the interior of a motor case 20. This motor is equipped with a brush 13 and a commutator segment 4 as electrical contacts and a commutator pedestal 5. At this moment, felt 16 is impregnated with a chemical made up of a mixture of 2-ethyl-1,3-hexandiol, which is provided in the motor case 20. Thus, this chemical is absorbed into the surfaces of the brush 13 and the segment 4 to form the monomolecular film, so that the lubricating ability can be improved and the abrasion of contacted portion reduced.

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 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.

(containing ST, PB, epoxy resins, etc. as additives) using conductive adhesive, spot welding, or caulking, but in small motors with these brushes, the commutator rotation Sometimes, 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 Foreign matter that promotes abnormal phenomena (mixed with sliding abrasion powder produced by sliding wheels) is often generated, which poses a problem. 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 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. 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.

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+PCT.
, Ag, etc., such as AgCu, AgCd, A
Consists of gCuCd, 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 scratches on the palm contact surface. Also,
Even when combined with a sintered carbon brush, the sliding resistance is lower than that of a precious metal alloy brush, but the blended materials that make up the brush contain a considerable amount of impurities such as Sin, which can cause scratches. There is a risk, and just like in the case of metal alloy brushes, in the case of precious metal alloy carbon, it is an unfavorable combination that tends to cause scratches on the contact surface. 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 60℃.
In the near future, the viscosity of the adhesive decreases significantly, the adhesive force between the anti-vibration rubber 9 and the sliding part 3 decreases, the vibration absorption ability decreases, and more sparks are generated, resulting in a long-life quality product. Furthermore, FIG. 5(C) shows another example of a structure in which vibration damping measures are taken for the brush sliding part 3, similar to FIG. 5(b). A vibration-proof sheet 12 is attached to the moving part 3 using an adhesive 11 having a structure in which an adhesive 8 is applied to both sides of a base material 10, as shown in FIG.
Compared to example b), 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 prevents shortening of the life of electrical contacts in vertical switches and relays with an open/close contact structure, slide switches and connectors with a similar movable contact structure between motor brushes and commutators, and small motors. be.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an electric contact such as a vertical movement switch or relay with an opening/closing contact structure, or a slide switch or connector with a sliding contact structure, in which the contact area is -Ethyl-1,3-hexanediol (hereinafter abbreviated as the chemical of the present invention) atmosphere.

To take an example of a small motor, past literature and experiments have revealed 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 part and the commutator segment slide, or if 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 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 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 the commutator segment adsorbs about 10 μg of unsaturated cyclic hydrocarbons, 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, it was found that when the chemical of the present invention is used, unlike unsaturated cyclic hydrocarbons such as styrene monomer and toluene, it burns well because it has oxygen in its molecular structure, and abnormal phenomena occur. It is farthest from the hard blackide formation, which is one of the two, and even if carbon is formed, it is extremely soft and can reduce the sliding resistance of the brush sliding part and commutator segment. 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 case, and the hydroxyl group of the present invention strongly adsorbs to metal surfaces. A sufficient effect can be obtained. In addition, good results can be obtained if the electrical contact to which the chemical of the present invention is placed has a nearly hermetic structure with little air circulation, or if the device itself into which the electrical contact is installed has a structure with little air circulation. .

In the adsorption of chemicals of the present invention, Au, Pd, Pt, Ag
, etc. and their alloys, such as commutator segments and brushes, as well as brushes made of Cu, sintered carbon brush surfaces, and other metal parts constituting motors. It also adsorbs onto the surface of surfaces, preventing highly reactive gases (styrene monomer, toluene, etc.) from adhering to the surface. This is because the chemical of the present invention forms 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: 2-ethyl-1,
3-hexanediol: C&H1l ・C
,H,・(on).

Molecular structure: CH, -CH-Ctl-CHz-CHz-
CLI 1 0il CzHs OH Water absorption rate: 4% (40° C., 90% RH, 1 atm).

The above-mentioned chemicals of the present invention can be used in small motors such as brushes,
Because it adsorbs to the commutator segment surface and forms a monomolecular film, lubricity is greatly improved and wear on the contact parts is significantly reduced.

The same effect can also be achieved in electrical contacts such as vertical switches and relays with an open/close contact structure, slide switches and connectors with a sliding contact structure.

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 the chemical of the present invention, 17
is the magnet wire wrapped around the 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 placed near the brush sliding part 3 on the bracket 14, and in the embodiment shown in FIG. In the embodiment, the brush 13
It is installed in Case 20, which is far away from the

Further, in each of the embodiments, the atmosphere inside the case becomes a vapor atmosphere due to the chemical of the present invention, so that the chemical of the present invention is adsorbed onto the surfaces of the brush and the commutator segment.

Comparative Example 1 in which experiments were conducted on the following Comparative Examples and Examples
) Conventional product comparison example 2) Test product comparison example in a styrene monomer atmosphere 3) Test product example in a toluene atmosphere 1) Test in an atmosphere where the present invention was mixed at a ratio of 1=1 However, even if there are some impurities in the ingredients of the drug of the present invention,
The drug of the invention exhibits remarkable effects.

The test results are shown in the table below.

The motor used in the margin test will be explained below with reference to FIG. This motor is a DC motor with an outer diameter of 30 mm and a height of 25 mm, with a rated output of 0.1 W, and the operating conditions during the test were 4.2 VDC.
It is 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. Further, a sintered porous field magnet 19 impregnated with the chemical of the present invention had a holding force of 0.1 to 0.3 g, and was able to obtain a remarkable effect.

Furthermore, a device sealed in a gas-permeable film or case such as polyethylene 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.

FIG. 6 is a rectified waveform of a small motor using the chemical of the present invention.

(a) is the rectification waveform of the conventional product before the test at 60°C and 5% RI (atmosphere). Rectified waveform and 1 before 60℃, 5%RH atmosphere test
0 (The rectification waveform (c) of Comparative Example 2 after the 1-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 surface of the commutator segment. and 30
The rectification waveform (d) of Comparative Example 3 after the 0-hour test is 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.The above explanation of the effect of the invention As is clear from the above, the present invention provides the following effects.

1) By adsorbing the chemical of the present invention to the surface of the sliding part, a lubricating effect is exerted, which has the effect of preventing abnormal wear and welding of the sliding contact surface and the resulting abrasion damage.

2) Even if there is an organic gas with a benzene ring such as styrene monomer or toluene, it will be protected by the film of the chemical of the present invention adsorbed on the surface of the sliding part, and the formation of black particles will be minimal, resulting in poor contact between the contacts. can be prevented. In addition, since contact failure does not occur, the generation of electrical noise is also reduced, and when used in small motors, for example, the speed can be stabilized. 3) The lubricating action of the chemical of the present invention reduces wow and flutter in equipment in which the motor is used, such as operating voltage: 1 to 3.
When a micromotor with a current value of 0 V and a current value of around 100 mA is operated in an atmosphere containing the chemical of the present invention, the current value decreases by 5 to 10%, resulting in energy savings.

4) The chemical of the present invention has a damping effect that suppresses vibrations generated by sliding motion, making it possible to reduce mechanical noise by 1 to 10%.

5) The hygroscopic property of the chemical of the present invention is that it has hydrophilicity -OH
The balance between groups and hydrophobicity (C-C-<carbon bonds) is ideal, and even in an atmosphere of 40°C 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 and transferred, it becomes possible to impregnate parts at room temperature, resulting in excellent productivity and long effect duration.

[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, FIGS. 5(a) to 5(C) are diagrams showing the typical configuration of a conventional brush sliding part, and FIGS. 6(a) to 6(d) are diagrams showing the configuration of a commutator. It is a figure which shows the rectified waveform of. 3... Commutator sliding part, 4...
- Commutator segment, 16...Felt, 20...Motor case. Name of agent: Patent attorney Toshio Nakao 1 person 3-Brush υyu > Moving part 1 Figure 14--Fragut I6--Felt Figure 2Figure 3Figure 4Figure 5

Claims (2)

[Claims] (1) 2-ethyl-1,3-
An electrical contact characterized by being coated with a mixture of hexanediol. (2) 2-ethyl-1,3-hexanediol is 2-ethyl-1,3-hexanediol.
The electrical contact according to claim 1, which is used after being dissolved in methyl 2,4-pentanediol.