JPS6230191A - Lubricant - Google Patents

Abstract

PURPOSE:To provide a lubricant consisting of 7-menthanol, effective to improve the lubricity and abrasion resistance by applying to the surface of an electrical contact or a no-voltage sliding part, and enabling to prolong the life at a high temperature and to keep the contact, etc., in high-quality state. CONSTITUTION:A monomolecular film of 7-methanol of formula is formed by adsorbing the compound to the surface of an electrical contact having an electrical contact structure, such as a vertically movable switch having openable contact structure, a relay, a commutating mechanism of a small-sized motor, a slide switch, connector, etc., having sliding contact structure or to the surface of a no-voltage sliding part. For example, a polyester felt is cleaned and defatted with a polyfluoroethylene liquid, impregnated with 7-methanol and inserted into the gap of a DC motor. EFFECT:The occurrence of imperfect contact between electrical contacts and the generation of electrical noise are decreased, the wow and flutter of a small- sized motor are reduced, and the vibration-damping effect, etc., can be imparted by the use of the lubricant.

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. This relates to lubricants used for electrical contacts or sliding parts to which no voltage is applied.

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 a conductive material with elasticity, such as a thin plate or wire of copper, beryllium, copper-titanium alloy, phosphor bronze, or nickel silver, and a noble metal alloy (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.

s, Pb, epoxy resin, etc. as additives) using conductive adhesive, spot welding, or caulking. However, in small motors with these brushes, When the commutator rotates, the brush moving part vibrates unnecessarily, which causes abnormal welding on the contact surface of the brush moving part with the commutator segment, and blackening (carbon and brush) due to spark generation. (mixture of sliding wear particles generated between commutator segments)
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 the brush sliding part that comes into contact with the commutator segment is integrally molded with a brush base that is supported by support means provided on the lid of the 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, the chips generated by this scraping accumulate in the gap between the adjacent commutator segments 40 (section b in Fig. 4). The commutator segments become electrically conductive and the rotation becomes unstable.

For example, when the surface roughness of the commutator segment surface becomes rough due to wear, it causes brush vibration, which promotes the generation of electrical sparks, which further progresses wear and causes abnormal wear, electrical noise, and rectification. The performance of the motor itself will deteriorate due to positional deviation.

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 3, which are in contact with each other, are subject to 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 Ag Cu, Ag Cd
, A g Cu Cd , A g Cu T +
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. 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 SiO□. There is a risk of abrasions, and as with noble metal alloy brushes, precious metal alloy carbon is an unfavorable combination in that it is more likely 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, 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. 2. It becomes difficult to obtain high-quality products with long lifespans.

Furthermore, FIG. 5(c) shows another example of a structure in which vibration damping measures are taken for the brush sliding portion 3, similar to FIG. 5(b). That is, the vibration-proof sheet 12 is attached to the base material 10 on the brush sliding part 3.
is pasted with an adhesive 11 having an adhesive 8 coated on both sides.Compared with the example shown in FIG. 5(b) above,
Although the decrease in viscosity of the adhesive at high temperatures can be suppressed to some extent, it is insufficient, and long life and high quality at high temperatures cannot be satisfied.

The ambient temperature for this device is -10°C to +6°C.
Many are used at 0°C.

The present invention provides vertical movement switches and relays with an open/close contact structure, rectifier mechanisms for small motors, slide switches with a sliding contact structure, electrical contacts of electrical connection structures such as connectors, or sliding parts to which no voltage is applied. The purpose is to allow smooth sliding.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention uses 7-menthanol as a lubricant to be adhered to the surface of the sliding part.

This 7-menthanol becomes vapor depending on the ambient temperature,
It is configured to adhere to the surface of the sliding part. In addition, in order to simplify the configuration, a configuration in which the coating is applied directly to the sliding portion may be used.

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 continuity occur. The condition where abnormality is likely to occur is the atmosphere of the area where the brush sliding part and the commutator segment slide.
Alternatively, unsaturated cyclic hydrocarbons may be present or 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 wear particles produced 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 (due to 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, 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 hydrocarbons such as styrene monomer and toluene are 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, when 7-menthanol is used, unlike styrene monomer and toluene, it burns well because it has oxygen in its molecular structure, resulting in hard blackening, which is one of the abnormal phenomena. It is the furthest away from carbon formation, and even if carbon is formed, it is extremely soft and reduces the sliding resistance of the brush sliding part and commutator segment.

In addition, this effect is due to the fact that an atmosphere suitable for the vapor pressure of 7-menthanol can be created in the motor case even at high temperatures and low humidity where abnormal phenomena are likely to occur, and that the polar group of 7-menthanol has a strong effect on metal surfaces. Since it is adsorbed to the surface, sufficient effects can be obtained.

7 Au, Pd, and Pt by adsorption of menthanol.

Commutator segments and brushes made of highly catalytic materials such as Ag, etc. and their alloys, as well as C.
It also adsorbs to the surfaces of sintered carbon brushes, etc., and the surfaces of other metal parts that make up the motor, and prevents highly reactive gases (styrene monomer, toluene, etc.) from adhering to the surfaces. To prevent. This is because 7-menthanol is more strongly adsorbed than organic gases, such as styrene monomers and toluene, which are adsorbed by van der Waals attraction. The names of chemicals effective in the present invention and their properties are shown below.

・Molecular formula: Cb I(q (CHz 0H)(i
Cz H? ) Molecular structure: H2-OH Boiling point: 236°C (1 atm) Melting point: 20°C (1 atm) Water absorption rate: 0% (40°C, 90% RH, 1 atm)・Lubricating properties as it adsorbs to the electrical contacts of electrical connection structures such as segment surfaces, vertical switches with open/close contact structures, relays, slide switches with sliding contact structures, notches, connectors, etc., and forms a monomolecular film. The wear of the contact parts is markedly improved.

decrease.

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 the bottom of the motor case, 16 is the felt impregnated with 7-menthanol, 1 is the bracket that holds the brush etc.
7 is a magnet wire wrapped around the rotor core 18, 1
9 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 example of Brush 1
It is installed in case 20, which is separate from case 3.

Further, in each of the embodiments, the purpose is to create a vapor cloud of 7-menthanol in the atmosphere inside the case and to cause 7-menthanol to be adsorbed onto the brush and commutator segment surfaces, 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 7-menthanol atmosphere. .

Note that even if there are some impurities in the components of 7-menthanol, 7-menthanol still exhibits a remarkable effect.

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 0.1 W, 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 7-menthanol was installed in the gap of the motor, the 7-menthanol 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. Remarkable effects could also be obtained by using open-cell foamed plastic or rubber sponge instead of the polyester felt 16.

Moreover, the sintered porous field magnet 19 impregnated with 7-menthanol is 0.1 to 0.
It had a holding force of 3g and a remarkable effect could be obtained.

In addition, a device sealed in a gas-permeable film or case made of polyethylene and installed inside a small motor had the ability to retain 7-menthanol and had a remarkable effect.

In addition, in Fig. 6, (a) shows the rectification waveform before the test of the conventional product in a 60°C 55% RH atmosphere and the rectification waveform after the 300-hour test, and (b) shows the rectification waveform of the unsaturated cyclic hydrocarbon styrene monomer. Rectification waveform before 60°C, 5% RH atmosphere test and Comparative Example 1 after 100 hours test
c) shows the rectification waveform before the 60°C 15% RH atmosphere test and Comparative Example 2 after the 300-hour test when approximately 10 μg of unsaturated cyclic hydrocarbon (toluene) is adsorbed on the surface of the commutator segment. Further, (d) shows the rectification waveform before the 60° C., 5% atmosphere test and the rectification waveform after the 1500 hour test in the 7-menthanol atmosphere of the present invention.

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

1) By adsorbing 7-menthanol 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. 1st
An example of the results is shown in the table. 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 7-menthanol adsorbed on the surface of the sliding part, and the formation of blackening will be minimal, resulting in contact points. 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 when used in small motors, for example, the speed can be stabilized. Wah/wow of equipment in which motors are used
Reduce flutter. Table 1 shows an example of the results.

3) 7 Menthanol has a damping effect that suppresses vibrations generated by the sliding movement of the brush commutator, and 1
Allows for ~10% reduction in mechanical noise. Table 1 shows an example of the results.

4) The hygroscopicity of 7-menthanol is 10H, which has hydrophilicity.
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.

As a result of 1) to 4) above, the quality of the motor was improved and its lifespan was significantly extended.

Margin below.

[Brief explanation of the drawing]

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 5(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 6(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... Old commutator segment, 16... Felt,
20. Old... Motor case.

Claims (1)

[Claims] A lubricant characterized in that the lubricant to be applied to the surface of electrical contacts or sliding parts to which no voltage is applied is composed of 7-menthanol.