JPS6155877A - 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 Field of Industrial Application The present invention is applicable to small motors used for driving tapes in tape recorders, video tape recorders, etc. , relating to electrical contacts such as connectors.

The configuration of the conventional example and its problems can be explained using an example of a small-sized upper-to-lower type, which 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 conductive materials with elasticity, such as copper, copper, copper titanium alloys, phosphor bronze, and nickel silver thin sheets or wires and noble metal alloys (e.g., Au, P).
d, 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 sintered carbon brush (for example, C carbon, λg carbon, Cu carbon, AgCu carbon, and SiC,
Carbon plastic containing MoS2, Pb, epoxy resin, etc. as additives is formed by means such as conductive adhesive, spot welding, or pressure bonding, but in small motors with these brushes, When the commutator rotates, the commutator sliding part vibrates unnecessarily, which causes abnormal welding to occur on the contact surface of the commutator sliding part to the commutator segment, and blackening (carbon This often causes problems due to the formation of foreign matter that promotes abnormal phenomena (mixture of sliding wear particles generated between the brush and the commutator segment). There is one in which the commutator sliding part that comes in contact with the other is molded integrally with a plan base that is supported by support means provided on, for example, the lid of the motor case.

FIG. 4 shows the state of contact between the single-layer blank and the commutator segment.

In FIG. 4, the commutator sliding portion 3 is bent from the plan base 2 supported by the brush support means 1.
is growing. This commutator sliding portion 3 has elasticity because it is bent from the brush base 2, and is in contact with the commutator segment 4 in a suppressed state.

This pressing force can be set to a required value by appropriately selecting the bending angle between the brush base 2 and the rotor/utator sliding part 3. Also, commutator
The segment 4 is fixed to the motor rotating shaft 6 via an insulating cylinder 5, and rotates with the rotation of the motor.

Since the rotating commutator segment 4 and the commutator sliding part 3 are in sliding contact with each other, electrical sparks are likely to occur between them, and the generation of electrical sparks can cause electrical noise and damage to the commutator. Inconvenient conditions such as welding occurring on the sliding portion 3 will occur. The occurrence of this welding not only shortens the life of the brush, but also when welding occurs at the position where it starts to come into contact with each commutator segment 4 and at the position where it separates (part a in Fig. 4), this welding causes the commutator segment 4 to Furthermore, the cutting debris generated by this abrasion accumulates in the gap between adjacent commutator segments 4, which causes electrical conduction between the commutator segments. This has the disadvantage that the performance of the motor itself deteriorates. Note that electric sparks often occur at section a of the sliding section of the early commutator.

The biggest cause of this is the sliding of the brush. That is, electric sparks frequently occur due to the vibration of the brush, which promotes the occurrence of welding and causes roughness of the sliding surface. As the roughness increases, the number of electric sparks increases, and eventually it becomes impossible to obtain the required characteristics of the motor, leading to the motor stopping.

Generally, the material of the commutator sliding part 3 is a noble metal alloy brush or a sintered carbon brush as described above, and the material of the commutator segment 4 is AgCu,
kg(ld, A(CuCd, Cu, MuU alloy, AgPd alloy, AgCuTi alloy, etc.)
When noble metal brushes are used, since both are made of substantially the same material, the sliding resistance is as high as 1.0, which is an unfavorable combination that tends to cause scratches at the sliding interface. Also, if you use a sintered carbon brush,
Although the sliding resistance is lower than when using precious metal alloy brushes, there is a risk of scratches, and impurities such as 5i02 are mixed in the compounded materials that make up carbon brushes, making them difficult to use with precious metals. As with alloy brushes, this is an unfavorable combination that tends to cause scratches on the sliding surface.

The one depicted in Figure 5 (2L) which does not have means to suppress the electrical sparks that cause these defects,
In other words, if no vibration damping measures are taken for the commutator sliding part 3, the vibration of the commutator sliding part will be large, and therefore welding will easily occur even when used at room temperature, making it difficult to obtain a product with a long life and excellent quality. . Also, Figure 5 (
The one shown in b), in which anti-vibration rubber 9 is attached to commutator sliding part 3 with adhesive 8, has good vibration absorption at room temperature and can suppress the generation of sparks, but there is an upper limit for its use. When the temperature approaches 60°C, the viscosity of the adhesive decreases significantly, and the adhesion of the anti-vibration rubber 9 to the sliding parts decreases, the vibration absorption ability decreases, more sparks are generated, and the service life is reduced. This results in a short period of time and unstable quality.

Furthermore, as shown in FIG. 5(C), the anti-vibration sheet 12 is attached to the commutator sliding part 3 with an adhesive 11 having adhesive 8 applied to both sides of the base material 10. Compared to the example shown in Figure 5 above, the viscosity of the adhesive decreases to some extent at high temperatures, but it cannot be said to be sufficient.
It is not possible to obtain long life and high quality at high temperatures. This type of problem can be caused by cladding precious metal alloys (e.g., metal, Pd, Pt, carbon, Cu, etc. and their alloys), or by connecting thin plate materials to electrical connections such as connectors, as in the case of early small motors. This is also caused by the formation of black oxides at the electrical contacts of the structure. Problems such as poor contact, transfer of contacts due to generation of electric sparks, and welding occur.

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

Purpose of the Invention The present invention aims to shorten the life of electrical contacts in electrical connection structures such as commutators of small motors, vertical movement switches and relays with opening/closing contact structures, or slide switches and connectors with sliding contact structures similar to small motors. It provides an electric point to prevent.

Structure of the Invention In order to achieve the above-mentioned object, the present invention is provided in the vicinity of an electrical contact.

Moisture absorbing agent (silica gel, zeolite, acrylic acid, acrylic acid/vinyl alcohol based % starch based moisture absorbing polymerf...
...Abbreviated as (moisture absorbent of the present invention) below.

The entire blended member, such as resin, is fixed with adhesive or attached using a pressure bonding method. Since this (hygroscopic agent of the present invention) releases the moisture held by the ambient temperature, the relative humidity inside the case in which the contact is built in is configured to increase.

DESCRIPTION OF EMBODIMENTS FIG. 1 and FIG. 2 each show an embodiment of the present invention. Here, parts with the same names as those in FIG. It is resin. In the embodiment shown in FIG. 1, the resin 16 is placed near the commutator slider 3 on the placket 14, and in the embodiment shown in FIG. 2, 16 feet of resin is mounted on the brush base 2.

In each of these embodiments, the commutator slider 3 is fixed to the tip of the plan base 2, but as shown in FIG. It may have a sliding part, and the resin 16 may be placed on the sliding part.

In either case, the atmosphere inside the motor case is (
The moisture absorbent of the present invention creates a water vapor atmosphere and water molecules adsorb onto the brush and commutator segment surfaces.
It was for the purpose of making money, and the means by which it was obtained were not limited to this.

By the way, the state in which the commutator sliding portion and the commutator segment tend to weld easily, or the state in which welding, abnormal wear, or conduction failure easily occurs, is being clarified through literature and experiments to date. Abnormalities are likely to occur in the atmosphere where the brush sliding part and the commutator segment move, or if unsaturated cyclic hydrocarbons exist or are adsorbed in the commutator segment itself. . At this time, a foreign substance called blackide (a mixture of carbon and sliding wear powder generated between the plan and the commutator segment) is generated which promotes abnormal phenomena. This foreign object.

When unsaturated cyclic hydrocarbons are combusted by an arc between the moving parts and the commutator segment, the amount of carbon per unit volume is large, resulting in incomplete combustion and due to its molecular structure, This is thought to be because the bonding state of carbon becomes dense, resulting in hard carbon.

Also, the atmosphere has high relative humidity (over 40%).

If moisture adsorption to the commutator segment is sufficient, carbon is difficult to generate and the commutator segment
It has been clarified that the wear of the segments and plans is minimal and does not lead to abnormal phenomena. Based on these phenomena, a long-term operation experiment was conducted using a commutator segment with relative humidity e'i of 40% or more and L water G adsorbed.

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 the commutator segment has moisture adsorption, the abnormality of the commutator segment will be alleviated,
The results showed that the lifespan of small motors could be extended.

The experimental results are shown in Figure 6.

Therefore, in the present invention, in consideration of the above phenomenon, FIGS.
As shown in the embodiment of the figure, a resin 16 blended with the moisture absorbent of the present invention is placed near the commutator sliding part inside the motor housing 15 and the bracket 14.
is arranged.

This (hygroscopic agent of the present invention) adsorbs moisture to the commutator segment and brush surface by releasing moisture, so it is the most distant substance to the formation of hard black particles, which is one of the abnormal phenomena, and the commutator sliding movement. This reduces sliding resistance between the commutator segment and the commutator segment.

In the above configuration, high temperature and
An atmosphere with low humidity that matches the vapor pressure due to the moisture released by the moisture absorbent of the present invention (fdC) is created in the motor case. This moisture-releasing agent (the moisture absorbent of the present invention) strongly adsorbs moisture to the metal surface due to its polar group. This adsorption is stronger than that of organic gases, which are adsorbed by Van der Walls' attraction, and can be said to be a stable adsorption state.

% due to adsorption of water molecules due to moisture release of (hygroscopic agent of the present invention)
It adsorbs not only commutator segments and brushes with strong catalytic action made of Au, Pd, Pt, Ag, etc., but also those made of %Cu, the surface of sintered case/brush, and other metal surfaces. Gases that are highly reactive to the surface (styrene monomer.

toluene, etc.) from adhering to the product. This means that (the hygroscopic agent of the invention) is, for example, a styrene monomer.

This is because it adsorbs more strongly than organic gases such as toluene, which adsorb due to van der Waals attraction.

In addition, small motors whose normal operating ambient temperature ranges from -10'C to +60°C, vertical movement switches with open/close contact structure, relays, or slide switches with sliding contact structure,
It is particularly effective for electrical contacts in electrical connection structures such as connectors.The components of the moisture absorbent of the present invention are as follows: moisture absorbent (1) silica gel (2) zeolite (3) acrylic acid-based moisture absorbing polymer (4) acrylic acid・Vinyl alcohol-based moisture-absorbing poly(5)
Starch-based hygroscopic polymer (6) Other hygroscopic agents.

Water molecules due to the moisture release of the above-mentioned (hygroscopic agent of the present invention) are:
To form a monomolecular film by adsorbing to the electrical contacts of electrical connection structures such as brushes, commutator/segment surfaces, opening/closing contacts, vertical movement switches, relays, or sliding contact structure slide switches and connectors. ,
Lubricity has also been greatly improved.

Wear of the contact parts is also significantly reduced. (The results of the experiment are shown in the 6th
As shown in the figure. An example showing the results of an experiment.

To explain the motor shown in FIG. 3, this DC motor operated at %4.2V has an outer diameter of 30 mm and a height of 26 mm, and a current of 25 m flows through its circuit.

In addition, in the configuration shown in FIG. 3, motor 1 housing 1
5 is equipped with a resin containing (the moisture absorbent of the present invention). In FIG. 3, 17 is a rotor core, 18 is a magnet wire, 19 is a magnet, and 2o.

21 is a metal bearing.

The moisture absorbent of the present invention is added to the resin provided inside this motor.
In the blended product, the moisture absorbent (of the present invention) gradually released moisture, and a remarkable effect could be obtained. This resin 1
6. By selecting the material, it is possible to make a quick meal that releases moisture quickly.

In addition, in FIG. 6, A and B show rectified waveforms in a styrene monomer atmosphere containing unsaturated cyclic hydrocarbons, and for humans, the rectified waveforms before the s%RH test at 60°C, and B show the rectified waveforms at 60°C,
This is the rectified waveform after a 5-inch RH test for 100 hours. Also,
C and D show the confirmation results in the atmosphere (moisture absorbent of the present invention), C shows the rectification and waveform before the 60" Cr5%RH test, and D
is the rectified waveform after testing at 60"C, 5% RH for 1600 hours.

Effect of the invention As is clear from the above description, according to the present invention.

It has the following effects.

(1) In vertical switches and relays with open/close contact structures for relatively low voltages of about 1 V to 30 V, organic gases with benzene rings, such as styrene monomer and toluene, are adsorbed onto the contact surface (this invention It is protected by a monomolecular film of water released by the moisture absorbent (hygroscopic agent), and the formation of black compounds is minimal, preventing poor contact between the contacts.

(2) In electrical contacts with a sliding contact structure for relatively low voltages of about IV to 30 V, the monomolecular film of water released from the moisture absorbent (of the present invention) adsorbed to the contact surface has a lubricating property. This has the effect of preventing damage and abnormal wear and chafing of the sliding parts.

[Brief explanation of drawings]

1 and 2 are block diagrams of a small motor according to an embodiment of the present invention, FIG. 3 is a sectional view of a small motor according to another embodiment of the invention, and FIG. 4 is a conventional example 1. ．． 1.
lJ configuration diagram Figures 5 (2L) to (C) are diagrams each showing the configuration of the commutator sliding part of the conventional example, and Figure 6 is a diagram showing the results of the rectified waveform of a small motor that confirmed the effects of the present invention. It is. 2...Brush base, 3...Commutator moving part, 4...Commutator segment, 14...Bracket, 16... Motor housing, 16... (moisture absorbent of the present invention)
Breaded resin. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4 Figure 5 (α) (b) Figure 6 □ρ

Claims (1)

[Claims] An electrical contact characterized by having a moisture absorbent placed nearby.