JPH0568936B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a small motor used for driving a tape in, for example, a tape recorder or a video tape recorder.

Conventional Structure and Problems There are generally 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, nickel silver thin sheets or wires, and noble metal alloys (such as Au,
This is a structure in which Pd, Pt, Ag, Cu, etc. and their alloys are clad or joined to a part of a thin plate material or wire rod by means such as spot welding, and the other is the thin plate material mentioned above. , or a sintered carbon brush as part of the wire (for example, carbon brush made of C carbon, Ag carbon, Cu carbon, AgCuC carbon, and those materials mixed with SiC, MoS ₂ , Pd, epoxy resin, etc. as additives) ) is formed by means such as conductive adhesive, spot welding, or pressure bonding. However, in small motors having these brushes, the commutator sliding part vibrates unnecessarily when the commutator rotates, which causes abnormal welding on the contact surface of the commutator sliding part with the commutator segment. It is said to be a black compound (a mixture of carbon and sliding abrasion powder generated between the brush and the commutator segment) caused by the generation of sparks.
This often results in the formation of foreign substances that promote abnormal phenomena, which poses a problem.

In some brushes for small motors, a commutator sliding portion that slides on a commutator segment is molded integrally with a brush base that is supported by support means provided on, for example, a lid of a motor case. The contact between such a brush and the commutator segment is shown in FIG.

In FIG. 1, a bent commutator sliding portion 3 extends from a brush base 2 supported by a brush support means 1. This commutator sliding portion 3 has elasticity due to being bent from the brush base 2, and is in contact with the commutator segment 4 in a pressed state. and,
This pressing force can be achieved by appropriately selecting the bending angle between the brush base 2 and the commutator sliding part 3.
It can be any value you want. Further, the commutator 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, electrical sparks are likely to occur between them, and the generation of these electrical sparks can cause electrical noise and the commutator sliding part 3. Unfavorable conditions such as welding on the 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 leaves (section a in Fig. 1),
This welding causes abrasion and damage to the surface of the commutator segments 4, and furthermore, cutting debris generated by this abrasion collects in the gap between adjacent commutator segments 4, thereby causing the commutator segments 4 to become damaged. There is a disadvantage that the segments are electrically connected to each other, and the performance of the motor itself is degraded. Incidentally, electric sparks are often generated at section a of the commutator sliding section.

The biggest cause of this is the vibration of the brush. That is,
Vibration of the brush frequently generates electric sparks, which promotes welding and causes roughening 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 mentioned above, and the material of the commutator segment 4 is AgCu, AgCd, AgCuCd, Cu, Au alloy,
AgPd alloy, AgCuTi alloy, etc., and when using a noble metal alloy brush, the sliding resistance is as high as 1.0 because the two materials are almost the same, which is an unfavorable combination that tends to cause scratches at the sliding interface. It is. Furthermore, although the sliding resistance is lower when using a sintered carbon brush than when using a noble metal alloy brush, there is a risk of scratches, and the compounded materials that make up the carbon brush contain SiO ₂ These impurities are mixed in, creating an unfavorable combination in which abrasions are likely to occur at the sliding interface, similar to noble metal alloy brushes.

If the structure shown in Figure 2a does not have a means to suppress the electric sparks that cause these defects, that is, if no vibration damping measures are taken in the commutator sliding part 3, the commutator The vibration of the sliding parts is large, and therefore welding easily occurs even when used at room temperature, making it difficult to obtain a product with a long life and excellent quality. In addition, as shown in FIG.
The one pasted with this adhesive has good vibration absorption at room temperature and can suppress the generation of sparks, but when the temperature reaches the upper limit of 60°C, the viscosity of the adhesive decreases significantly, causing the vibration-isolating rubber 9 to slip on the sliding part. The adhesive strength of the material decreases, the vibration absorption ability decreases, and sparks occur more frequently, resulting in a product with a short life and unstable quality.
Furthermore, as shown in FIG. 2c, the anti-vibration sheet 12 is attached to the commutator sliding part 3 using an adhesive 11 having an adhesive 8 coated on both sides of the base material 10, as shown in FIG. Compared to the example shown in FIG. b, the decrease in the viscosity of the adhesive at high temperatures is to some extent small, but it is not sufficient, making it impossible to achieve long life and high quality at high temperatures.

Please note that the ambient temperature for this device is -10℃~
Many are used at +60℃.

Purpose of the Invention The present invention aims to improve the sliding properties of the commutator sliding part and the commutator segment, prevent shortening of the motor life due to scratch damage on the commutator segment surface, and further improve the sliding properties of the commutator segment. The present invention provides a high-performance small motor that reduces wow and flutter when incorporated.

Structure of the Invention In order to achieve the above-mentioned object, the present invention includes a thin plate-like or linear base made of an elastic metal body, and a commutator extending from the brush base or fixed to a part of the brush base. In a small motor equipped with a brush having a sliding part, a member impregnated with an oxymonocyclic terpene, such as felt, is fixed with adhesive or attached to a part of the motor case, for example, near the commutator sliding part on the bracket. Attach by crimp method or other means. This oxy monocyclic terpene has a linear carbon bond without a benzene ring or has a side chain, and has 1
Depending on the conditions of use, select an appropriate material whose boiling point is 250°C from among substances whose boiling point is around 100°C under atmospheric pressure.
This oxymonocyclic terpene turns into vapor depending on the ambient temperature, and the inside of the motor case is configured to be in an atmosphere of oxymonocyclic terpene.

In order to simplify the motor configuration, a configuration may be used in which the oxymonocyclic terpene is directly applied to the brush or commutator sliding portion.

DESCRIPTION OF EMBODIMENTS FIGS. 3 and 4 each show an embodiment of the present invention. Here, parts with the same names as those in Figure 1 are given the same symbols, and
14 is a bracket for holding brushes, etc.; 15 is a motor housing; and 16 is felt impregnated with oxymonocyclic terpene.

In the embodiment of FIG. 3, the felt 16 is located on the bracket 14 in the vicinity of the commutator slide 3, and in the embodiment of FIG. 4, the felt 16 is mounted on the brush base 2.

In all of these embodiments, the commutator sliding part 3 is fixed to the tip of the brush base 2, but as shown in FIG. It may have a moving part and the felt 16 may be placed on the sliding part. In any of the embodiments, the atmosphere inside the motor case becomes a vapor atmosphere due to the oxymonocyclic terpene, and the purpose is to cause the atmospheric gas to adsorb onto the surfaces of the brushes and commutator segments. Not as long.

By the way, in the literature and experiments to date, the conditions in which the commutator sliding portion and the commutator segment are likely to be welded together, or the conditions in which welding, abnormal wear, or poor conduction are likely to occur are being clarified. Conditions where abnormalities are likely to occur include the brush sliding part and the commutator.
This is the case when unsaturated cyclic hydrocarbons are present or adsorbed in the atmosphere of the sliding portion of the segment or in the commutator segment itself. At this time, a foreign substance called blackide (a mixture of carbon and sliding abrasion powder generated between the brush and the commutator segment) is generated which promotes the abnormal phenomenon.

This foreign material is caused by incomplete combustion due to the large amount of carbon per unit volume when unsaturated cyclic hydrocarbons are combusted by an arc between the sliding part and the commutator segment, and also due to their molecular structure. However, this is thought to be because the bonding state of the produced carbon becomes dense, resulting in hard carbon. Furthermore, it has been found that in atmospheres other than unsaturated cyclic hydrocarbons and when adsorbed by the commutator segment, the carbon produced is soft and does not lead to abnormal phenomena, although this is due to its molecular structure. . Based on these phenomena, we conducted long-term operation experiments using a commutator segment that adsorbed trace amounts of hydrocarbons.
In this experiment, there was a high probability of abnormal wear occurring in the commutator segment under high temperature and low humidity.

If about 10 μg of hydrocarbons are adsorbed in the commutator segment, abnormal phenomena in the commutator segment will be alleviated and the life of the small motor will be extended. (However, this data is based on the case where there is no continuous replenishment of hydrocarbons.) (The results of the experiment are shown in Fig. 5) Therefore, in the present invention, in consideration of the above phenomenon, the third
As shown in the embodiment shown in FIG. 4, a felt 16 impregnated with an oxymonocyclic terpene is placed near the commutator sliding part inside the motor housing 15 and the bracket 14. . These oxymonocyclic terpenes are the most different from unsaturated cyclic hydrocarbons in terms of their molecular structure, and therefore are the ones that are farthest away from the formation of hard black compounds, which is one of the abnormal phenomena, and carbon formation is accelerated. However, it is extremely soft and reduces the sliding resistance between the commutator sliding part and the commutator segment.

In the above configuration, an atmosphere corresponding to the vapor pressure of oxymonocyclic terpenes is obtained in the motor case at high temperatures and low humidity where abnormal phenomena are likely to occur. This oxymonocyclic terpene having a hydrogen bond and not having a benzene ring strongly adsorbs to the metal surface due to polar force. This adsorption is stronger than that of organic gas, which is adsorbed by Van der Waals attraction, and can be said to be a safe adsorption state. By adsorption of this oxymonocyclic terpene, Au, Pd, Pt,
It adsorbs not only to the commutator segments and brushes made of Ag etc., which have a strong catalytic effect, but also to those made of Cu, to the surface of sintered carbon brushes, and to other metal surfaces. Prevents the adhesion of expensive gases (styrene monomer, toluene, etc.).

This is because the adsorption power of oxymonocyclic terpenes is stronger than that of organic gases, such as styrene monomers and toluene, which are adsorbed by Van der Waals attraction, except for varaffins. Figure 6 shows the results of the experiment. Figure 6 is a photograph of the commutator segment surface, where a shows the condition of the commutator segment surface before the test, and b shows the condition of the commutator segment surface in an unsaturated cyclic hydrocarbon (styrene monomer) atmosphere (60°C, 5% RH) 100 Figure 3 shows the condition of the commutator segment surface after the time test. Further, c shows the state after a 300-hour test at 60° C. and 5% RH when approximately 10 μg of hydrocarbon (toluene) was adsorbed on the surface of the commutator segment. Furthermore, d is (60°C, 5%
RH) Shows the condition after 1500 hours test.

Moreover, for small motors whose normal operating environment range is -10℃ to +60℃, the boiling point at 1 atmosphere is 100℃.
It is effective from substances around ℃ to around 250℃, and when listed by type of oxymonocyclic terpene, γ-terpineol...114-115℃ (boiling point under 1 atmosphere) β-terpineol...209-210 °C (boiling point at 752 mmHg) α-terpineol...219-221 °C (boiling point at 1 atm) 1-Menthol...216.5 °C (sublimation at 1 atm) d-Tarpineol...209 °C (1 atm) sublimation) etc.

The above-mentioned oxymonocyclic terpenes adsorb to the surfaces of the brush and commutator to form a monomolecular film, which greatly improves lubricity and significantly reduces wear on the contact parts. (The results of the experiment are shown in Figure 5.) In Figure 5, A and B show the rectified waveforms in a styrene monomer atmosphere containing unsaturated cyclic hydrocarbons, and A is the waveform before the 60°C, 5% RH test. B is the rectified waveform after a 100-hour test at 60°C and 5% RH. In addition, for C and D, approximately 10 μg of hydrocarbon (toluene) is applied to the surface of the commutator segment.
Showing the confirmation results when adsorbed, C is 60℃, 5
Rectified waveform before %RH test, D is 60℃, 5%
This is the rectified waveform after a RH300 hour test. moreover,
E and F show the confirmation results in the oxymonocyclic terpene atmosphere according to the present invention, E is the rectified waveform before the 60°C, 5% RH test, and F is the rectified waveform after the 60°C, 5% RH test for 1500 hours. be.

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

By adsorbing the oxymonocyclic terpenes to the commutator segment and the brush surface, a lubricating effect works, which has the effect of preventing abnormal wear and scratch damage on the sliding parts.

Even if there is an organic gas with a benzene ring such as styrene monomer or toluene, it will be protected by a film of oxymonocyclic terpenes adsorbed on the brush and commutator segment surfaces, and the formation of black compounds will be minimal. This can prevent poor contact between the two. In addition, since contact failures do not occur, the generation of electrical noise is reduced, and the speed of small motors that would otherwise occur due to unstable contact is stabilized, resulting in less wow and flutter in equipment that uses small motors. It has the effect of reducing

As a result of the above, the quality of the small motor can be improved and its life can be significantly extended.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a conventional example, FIGS. 2 a to c are diagrams showing the configuration of a commutator sliding part of a conventional example, and FIGS. 3 and 4 are configuration diagrams of an embodiment of the present invention, respectively. 5A to 5F are diagrams showing rectifying waveforms of the conventional example and the present invention, and FIGS. 6A to 6D are explanatory diagrams showing the states of the commutator segment surfaces of the conventional example and the present invention. 3...Commutator sliding part, 4...Commutator segment, 14...Bracket, 15...
Housing, 16... Felt impregnated with oxymonocyclic terpenes.

Claims (1)

[Claims] 1. A small motor that has an atmosphere of oxymonocyclic terpenes that do not have a benzene ring inside the motor case that houses the brush mechanism and the commutator, where the brush and the commutator slide in contact with each other.