JPH0710154B2 - Small motor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small motor used for driving a tape such as a tape recorder or a video tape recorder.

Configuration of Conventional Example and Problems There are generally two types of brushes in a small motor. One is elastic conductive material such as copper, beryllium copper, copper-titanium alloy, phosphor bronze, nickel silver thin plate material or wire material, and precious metal alloys (eg Au, Pd, Pt, Ag, Cu and their (Alloy) is clad or joined to a part of a thin plate or wire by spot welding or the like. The other is a sintered carbon brush (for example, a sintered carbon brush) described above on a part of the thin plate or wire. S, C carbon, Ag carbon, Cu carbon, AgCuC carbon, and their materials
Carbon brushes containing iC, MoS ₂ , Pb, epoxy resin, etc. as additives are formed by means of conductive adhesive, spot welding, crimping method, etc. Causes the commutator sliding part to vibrate unnecessarily when the commutator rotates, which causes abnormal welding on the contact surface of the commutator sliding part with respect to the commutator segment, and the black matter (carbon and A problem often arises in that foreign matter is often generated which promotes an abnormal phenomenon called a mixture of sliding wear powder generated between the brush and the commutator segment.

In some small motor brushes, a commutator sliding portion that is in sliding contact with a commutator segment is integrally formed with a brush base portion that is supported by a supporting means provided on, for example, a lid of a motor case. The contact state 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 portion 2 supported by a brush supporting means 1. This commutator sliding part 3 is a brush base 2
It has elasticity by being bent from and is in contact with the commutator segment 4 in a pressed state. Then, this pressing force is obtained by appropriately selecting the bending angle between the brush base 2 and the commutator sliding part 3.
It can be any value you want. The commutator segment 4 is fixed to the motor rotating shaft 6 via the insulating cylinder 5 and rotates with the rotation of the motor.

In this way, since the rotating commutator segment 4 and the commutator sliding portion 3 are in sliding contact with each other, electric sparks are easily generated between them, and electrical noise and commutator sliding are generated with the generation of the electric sparks. An inconvenient state such as welding on the portion 3 will occur. And the occurrence of this welding not only shortens the life of the brush, but also
When welding occurs at a position where the commutator segment 4 starts to contact and a position where the commutator segment 4 starts to separate (part a in FIG. 1), the surface of the commutator segment 4 is scratched and damaged by the welding, and further caused by this scraping. There is a disadvantage that cutting wastes are accumulated in the gap between the commutator segments 4 adjacent to each other, and the commutator segments are electrically connected to each other, and the performance of the motor is deteriorated. .
It should be noted that electric sparks are often generated at the portion a of the commutator sliding portion.

The biggest cause of this is the vibration of the brush. That is, electric sparks frequently occur due to the vibration of the brush, which promotes the occurrence of welding and causes the sliding surface to become rough. As the roughness becomes larger, the generation of electric sparks further increases, and eventually it becomes impossible to obtain the required characteristics of the motor, which may lead to the start and stop. 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 AgC.
u, AgCd, AgCuCd, Cu, Au alloys, Ag Pb alloys, AgCuTi alloys, etc., when using a precious metal alloy brush, these are
Since they are made of almost the same material, the sliding resistance is 1.0, which is a disadvantageous combination in which scratches easily occur at the sliding interface. Moreover, even the case of using a sintered carbon brush sliding resistance is smaller than when using a noble metal alloy brush, there is the risk of abrasions, also the compounding material constituting the carbon brushes SiO ₂ Impurities such as, for example, are mixed, which is a disadvantageous combination in which scratches are likely to occur at the sliding interface like the noble metal alloy brush.

The structure shown in FIG. 2 (a) which does not have the means for suppressing the electric sparks that cause these defects, that is, the commutator sliding part 3 which does not take any vibration damping measure is used. The vibration of the sliding part of the commutator is large, and therefore welding easily occurs even at room temperature, and it is difficult to obtain a product with a long life and excellent quality. Further, as shown in FIG. 2 (b), the one in which the vibration-preventing rubber 7 is attached to the commutator sliding portion 3 with the adhesive 8 has good vibration absorption at room temperature,
Sparks can be suppressed, but the maximum operating temperature of 60
When the temperature approaches ℃, the viscosity of the adhesive decreases remarkably, the adhesive strength of the anti-vibration rubber 7 to the vibrating part decreases, the vibration absorption capacity decreases and the number of sparks increases, the life is short and the quality is unstable. It will be something like. Further, as shown in FIG. 2 (c), the sheet for vibration prevention 9 is attached to the commutator sliding portion 3 with the adhesive 11 having the constitution in which the pressure sensitive adhesive 8 is applied to both sides of the base material 10. Compared with the example of FIG. 2 (b), the decrease in viscosity of the pressure-sensitive adhesive at high temperature is somewhat small but not sufficient, and it is impossible to obtain long life and high quality at high temperature.

The ambient temperature of this equipment is often -10 ℃ to + 60 ℃. In addition, in a motor with an applied voltage of more than 30V, even if welding of black matter, which will be described later, occurs on the sliding part of the commutator, the applied voltage is high, so there is sufficient electrical conduction between the brush and the commutator segment. It can be taken and it does not matter.

OBJECT OF THE INVENTION The present invention aims to improve the slidability of a commutator sliding part and a commutator segment to prevent shortening of the motor life due to scratch damage on the surface of the commutator segment, and also to devices such as tape recorders. It is intended to provide a high-performance small motor capable of reducing wow and flutter when incorporated.

To achieve the above object, the present invention provides a brush base made of a thin plate-shaped or linear metal elastic body and a commutator extended 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 a fatty acid, for example, a felt is fixed with an adhesive or a pressure bonding method in a part of the motor case, for example, near the commutator sliding part on the bracket. Install by means of. This fatty acid has a linear carbon bond that the benzene ring does not have, or has a side chain,
It is a fatty acid having one or more -COOH groups in its molecular structure and has a boiling point or melting point of 100 ° C at 1 atm.
It is especially effective to select an appropriate substance from the nearby substances that has a temperature of around 250 ° C, and it is possible to use substances up to around 300 ° C. The fatty acid becomes vapor depending on the ambient temperature, and the inside of the motor case is configured to be in the fatty acid atmosphere. In addition, in order to simplify the motor configuration, a configuration may be used in which the fatty acid is directly applied to the brush or the commutator sliding portion.

Description of Embodiments FIGS. 3, 4, and 5 show an embodiment of the present invention. Here, parts having the same names as those in FIG. 1 are given the same reference numerals, 12 is a bracket for holding a brush or the like, 13 is a motor housing, and 14 is a felt impregnated with a fatty acid. The commutator sliding part 3
Is made of carbon brush. In the embodiment shown in FIG. 3, the felt 14 is arranged near the commutator sliding portion 3 on the bracket 12, and in the embodiment shown in FIG.
A felt 14 is mounted on the brush base 2.

In the embodiment shown in FIG. 5, the motor housing 13 is equipped with the felt 14. In addition, in FIG.
Reference numeral 15 is a rotor core attached to the motor rotary shaft 6, 16 is a winding wound around the rotor core 15, and 17 is a motor housing 13.
A permanent magnet fixed to the inner surface of the bearing 18 is a bearing for supporting the motor rotating shaft 6.

In each of these examples, the commutator sliding portion 3 is fixed to the tip of the brush base 2, but as shown in FIG. 1, the commutator sliding portion is bent and extended from the brush base 2. Part, and the felt 14
May be equipped. In both cases, the atmosphere in the motor case consisting of the motor housing 13 and the bracket 12 becomes a vapor atmosphere of fatty acid, and the purpose is to adsorb on the brush and commutator segment surface by the atmosphere gas. , The means is not limited to this.

By the way, in the literature and experiments so far, the state where the commutator sliding part and the commutator segment are easily welded,
Alternatively, the state where welding, abnormal wear, and poor continuity are likely to occur is being clarified. Abnormality is likely to occur when the brush sliding part and the commutator segment are in an atmosphere where they slide, or when unsaturated cyclic hydrocarbons are present or adsorbed on the commutator segment itself. . At this time, a foreign matter called black matter (a mixture of carbon and sliding abrasion powder generated between the brush and the commutator segment) that promotes an abnormal phenomenon is generated.

When the unsaturated cyclic hydrocarbon burns by the arc between the sliding part and the commutator segment, this foreign matter has a large amount of carbon per unit volume and incompletely burns,
Although it is due to its molecular structure, it is considered that hard carbon can be formed because the binding state of the produced carbon becomes dense.

In addition, in the atmosphere of hydrocarbons other than unsaturated cyclic hydrocarbons, and in the adsorption to the commutator segment, it is due to its molecular structure, but the generated carbon becomes soft and it does not lead to abnormal phenomena. It has been elucidated. Based on these phenomena, a long-term operation experiment was conducted using a commutator segment in which a very small amount of hydrocarbon was adsorbed. In this experiment, there is a high probability that abnormal wear will occur in the commutator segment at high temperature and low humidity.

When about 10 μg of hydrocarbons are adsorbed on the commutator segment, the abnormal phenomenon of the commutator segment is mitigated, and the life of the small motor is extended. (However, this is the data when there is no continuous supply of hydrocarbons.) (Results of the experiment are shown in FIG. 6) Therefore, in the present invention, the above phenomenon is taken into consideration in FIGS.
As shown in the embodiment of FIGS. 5 and 5, the motor housing
A felt 14 impregnated with a fatty acid is arranged inside a bracket 13 and a bracket 12. These fatty acids differ most from unsaturated cyclic hydrocarbons in terms of their molecular structure, and are therefore the furthest from the formation of hard black oxide, which is one of the abnormal phenomena, and even if carbon is produced, it is extremely It becomes soft and reduces the sliding resistance between the commutator sliding part and the commutator segment.

In the above configuration, at a high temperature and a low humidity where an abnormal phenomenon is highly likely to occur, an atmosphere matching the vapor pressure of fatty acids can be obtained in the motor case. This fatty acid having a linear carbon bond or a side chain having no benzene ring has a single or a plurality of -COOH groups in its molecular structure, and the -COOH group has a polar force. To the metal surface,
-It has the adsorption power by the COOH bond.

The adsorption by -COOH bond is stronger than the organic gas adsorbed by the attraction of Van der Waals, and it can be said that the adsorption state is stable. By adsorption of this fatty acid,
Not only commutator segments and brushes made of Pt, Au, Pd, Ag, etc. with strong catalytic action, but also those made of Cu, and also adsorbed on the surface of sintered carbon brush and other metal surfaces However, it prevents the highly reactive gas (styrene monomer, toluene, etc.) from adhering to the surface.

This is because the adsorption power of the -COOH group is stronger than that of van der Waals adsorption of, for example, styrene monomer or toluene, that is, -COOH bond adsorption. Also, brushes, commutators,
Even when combustion occurs due to the arc between the segments, the fatty acids have oxygen in their molecular structure, and almost no tars are generated due to incomplete combustion, and the formation of black matter that causes poor contact is also generated. It is small, burns well, and does not cause contact failure.

Moreover, in the case of a small motor whose normal use environment range is -10 ° C to + 60 ° C, it is particularly effective that the boiling point or melting point at 1 atm is from 100 ° C to 250 ° C.
It can be used up to about 00 ° C. Listed by the type of fatty acid, pivalic acid …… 164 ° C (boiling point under 1 atm) isocrotonic acid …… 169 ° C (boiling point under 1 atm) isovaleric acid …… 177 ° C (boiling point under 1 atm) For example, n-octanoic acid: 239 ° C (boiling point under 1 atmosphere) malonic acid: 135 ° C (melting point under 1 atmosphere).

The above-mentioned fatty acids are adsorbed on the surface of the brush and commutator to form a monomolecular film, so the lubricity is extremely improved.
Wear on the contact area is also significantly reduced. (The result of the experiment is
Shown in the figure. ) In FIG. 6, (A) and (B) show a rectified waveform in an atmosphere of a styrene monomer having an unsaturated cyclic hydrocarbon, and (A) shows a rectified waveform before 60 ° C., 5% RH test,
(B) is a rectified waveform after a test at 60 ° C., 5% RH for 100 hours. In addition, (C) and (D) show the confirmation results when about 10 μg of hydrocarbon (toluene) was adsorbed on the commutator segment surface, and (C) is the rectified waveform before the test at 60 ° C and 5% RH ( D) is a rectified waveform after a test at 60 ° C, 5% RH for 300 hours. Further, (E) and (F) show the confirmation results in the fatty acid atmosphere according to the present invention, (E) is a rectified waveform before 60 ° C, 5% RH test, and (F) is 60 ° C, 5% RH1500. It is a rectified waveform after a time test.

EFFECTS OF THE INVENTION As is apparent from the above description, the present invention has the following effects.

By adsorbing the fatty acids on the commutator segment and the surface of the brush, a lubricating action is exerted, which has the effect of preventing abnormal wear and abrasion damage of the sliding part.

Even if there is an organic gas having a benzene ring such as styrene monomer or toluene, it is protected by a film of fatty acids adsorbed on the surface of the brush and commutator segment, and the formation of black matter is also minimal, resulting in contact between the brush and commutator segment. You can prevent defects. In addition, the occurrence of electrical noise is reduced because contact failure does not occur, and the speed of a small motor is stabilized due to contact instability.As a result, wow and flutter of equipment that uses a small motor There is an effect that reduction can be obtained.

As a result of the above, the quality of the small motor for relatively low voltage of about 1V to 30V is improved, and the life can be greatly extended.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a conventional example, and FIGS. 2 (a) to (c) are
Drawings showing the structure of the commutator sliding part of the conventional example,
FIGS. 3 and 4 are configuration diagrams of an embodiment of the present invention, and FIGS. 5 (a) and 5 (b) are longitudinal sectional views and transverse sectional views of a small motor according to still another embodiment of the present invention. 6 (A) to 6 (F) are diagrams showing rectified waveforms of the conventional example and the present invention. 3 …… Commutator sliding part, 4 …… Commutator segment, 12 …… Bracket, 13 …… Housing, 14 ……
Felt impregnated with fatty acids.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeru Kondo 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Brushes and their usage ", Nikkan Kogyo Shimbun, 2nd edition, issued March 1, 1978, PP. 149-150 (4) Effects of toxic gases and countermeasures

Claims (1)

[Claims] 1. A small motor having a brush mechanism section and a commutator, in which the brush and the commutator are in sliding contact with each other, wherein the boiling point at one atmospheric pressure is about 100 ° C. to 250 ° C. in the motor case. A small motor that has a linear carbon bond or a side chain and has an atmosphere of fatty acids having one or more -COOH groups in its molecular structure.