JPH0767258B2 - 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 of a tape recorder, a video tape recorder, or the like.

Structure of the conventional example and its problems Explaining with the example of a small motor with the most number of contact switching,
Generally, there are two types of brushes in a small motor. One is an elastic conductive material such as copper, beryllium copper, copper titanium alloy, phosphor bronze, nickel silver thin plate material or wire material and noble metal alloy (eg Au, Pd, Pt, Ag, Cu, etc. and their alloys). ) Is clad or joined to a part of a thin plate material or a wire material by means of spot welding,
The other is a sintered carbon brush (for example, C carbon, Ag carbon, Cu carbon, AgCu carbon, and Si for those materials) which is a part of the thin plate material or the wire material described above.
A carbon brush containing C, MoS ₂ , Pb, epoxy resin, etc. as an additive is formed by means of conductive adhesive, spot welding, or crimping method. , The commutator sliding part vibrates unnecessarily when the commutator rotates,
As a result, abnormal welding occurs on the contact surface of the commutator sliding part with respect to the commutator segment, and black matter (a mixture of carbon and sliding wear powder generated between the brush and the commutator segment) due to spark generation. It is often a problem that foreign substances are generated that promote the so-called abnormal phenomenon. In some brushes for small motors, 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 commutator base 5 and rotates with the rotation of the motor.

As described above, 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. Inconvenient conditions such as welding on the moving part 3 will occur. And
The occurrence of this welding not only shortens the life of the brush,
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 the 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. .
In addition, electric sparks are often generated in the a part of the commutator sliding part in the previous period.

The largest cause of this is brush sliding. 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 AgCu, AgCd, AgCuC.
d, Cu, Au alloys, AgPd alloys, AgCuTi alloys, etc.When using noble metal brushes, since these are almost the same material, the sliding resistance is 1.0 and scratches at the sliding interface This is a disadvantageous combination that is likely to occur. Also, when using a sintered carbon brush, although the sliding resistance is smaller than when using a noble metal alloy brush, there is a risk of scratches, and in the compounding material that constitutes the carbon brush , Impurities such as SiO ₂ are mixed, and as with the noble metal alloy brush, it is a disadvantageous combination in which scratches easily occur at the sliding interface.

The structure shown in FIG. 2a which does not have a means for suppressing the electric sparks that cause these defects, that is, the commutator sliding part 3 does not take any vibration damping measures, is a commutator. Since the vibration of the sliding part is large, welding easily occurs even at normal temperature, and it is difficult to obtain a product with a long life and excellent quality. In addition, as shown in FIG. 2b, the vibration preventive rubber 9 attached to the commutator sliding portion 3 with the adhesive 8 has good vibration absorption at room temperature and can suppress generation of sparks. When the temperature reaches 60 ° C, which is the maximum operating temperature, the viscosity of the adhesive decreases significantly, the adhesive force of the vibration-preventing rubber 9 to the commutator sliding part 3 decreases, and the vibration absorption capacity decreases, causing more sparks. , The life is short and the quality is unstable. Further, as shown in FIG. 2c, the commutator sliding part 3 is attached with the adhesive 11 having the constitution in which the vibration preventing sheet 12 is coated on both sides of the base material 10 with the adhesive 11 described above. Compared with the example of FIG. 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 motor is often -10 ° C to + 60 ° C. 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.

An object of the present invention is to improve the slidability of a commutator sliding portion and a commutator segment, prevent the shortening of the motor life due to abrasion damage on the commutator segment surface, and
It is intended to provide a high-performance small motor that can reduce wow and flutter when it is incorporated in a device such as a tape recorder.

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 provided with a brush having a sliding part, a paraffin having no benzene ring in a part of a motor case, for example, near a commutator sliding part on a bracket. Chemicals of the present invention 1 One or more -COO -Esters having a bond 2 Chemicals of the present invention 2 Alkyl amides having one or more —CONH-bonds Chemicals 3 of the present invention Secondary amines having one or more —NH-bonds Chemicals 4 of the present invention 1 singular or Tertiary amines having a plurality of -N = bonds Impregnated with at least one or more chemicals among chemicals 5 of the present invention [hereinafter abbreviated as chemicals of the present invention]. Material is deposited set by means such as anchoring or bonding method such as a felt with an adhesive. This (the chemical of the present invention) has a linear carbon bond having no benzene ring or has a side chain, and the boiling point thereof under 1 atm is around 100 ° C to 250 ° C. It is especially effective to select the appropriate one according to
It can be used up to about ℃. The (chemicals of the present invention) is turned into vapor depending on the ambient temperature, and the atmosphere of the chemicals of the present invention is formed in the motor case. In addition, in order to simplify the motor configuration, a configuration may be used in which the (chemical of the present invention) 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, the same reference numerals are given to the same names as those in FIG. 1, 14 is a plastic bracket for holding brushes, and 15 is a bracket.
A motor housing that forms a motor case with 14,
16 is a felt impregnated with (the chemical of the present invention). 17
Is a rotor core attached to the motor rotary shaft 6, 18 is a magnet wire wound around the rotor core 17, 19 is a field magnet fixed to the inner surface of the motor housing 15, and 20 is a field magnet.
Is a metal bearing that supports the motor rotating shaft 6. In the embodiment shown in FIG. 3, the felt 16 is arranged near the commutator sliding portion 3 on the bracket 14, and in the embodiment shown in FIG. 4, the felt 16 is mounted on the brush base 2.
Further, in the embodiment shown in FIG. 5, the motor housing 15 is equipped with the felt 16.

In each of these embodiments, the commutator sliding part 3 is fixed to the tip of the brush base 2, but the commutator sliding part bent and extended from the brush base 2 as shown in FIG. The felt 16 may be provided on the sliding portion.

In any of the embodiments, the atmosphere in the motor case becomes a vapor atmosphere due to (the chemical of the present invention), and the purpose is to adsorb on the brush and the commutator segment surface by the atmosphere gas. Not as long.

By the way, the state in which the commutator sliding portion and the commutator segment are easily welded, or the state in which welding, abnormal wear, or conduction failure is likely to occur is being elucidated in the literature and experiments so far. Abnormality is likely to occur when the brush sliding part and the commutator segment slide in the atmosphere or when the commutator segment itself contains or adsorbs unsaturated cyclic hydrocarbons. At this time, foreign matter is generated which promotes an abnormal phenomenon called black matter (a mixture of carbon and sliding wear powder generated between the brush and the commutator segment).

This foreign matter has a large amount of carbon per unit volume when the unsaturated cyclic hydrocarbon is burned by the arc between the sliding portion and the commutator segment, resulting in incomplete combustion,
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.

Also, in the adsorption of hydrocarbons other than unsaturated cyclic hydrocarbons and adsorption to commutator segments, it is due to the molecular structure, but the generated carbon becomes soft, which does not lead to abnormal phenomena. Has been done. 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, 1) It is highly probable that abnormal wear will occur in the commutator segment at high temperature and low humidity.

2) When about 10 μg of hydrocarbon is adsorbed on the commutator segment, the abnormality of the commutator segment is alleviated and the life of the small motor is extended. (However, this is the data when there is no continuous supply of hydrocarbons.) The results were obtained. The experimental results are shown in FIG.

Therefore, in the present invention, the above phenomenon is taken into consideration in FIGS.
As shown in the embodiment of the drawing, the felt 16 impregnated with (the chemical of the present invention) is placed in the vicinity of the commutator sliding portion inside the motor housing 15 and the bracket 14. These (chemicals of the present invention) are the most different from unsaturated cyclic hydrocarbons in terms of their molecular structure, and therefore,
It is the furthest from the formation of hard black matter, which is one of the abnormal phenomena, and becomes extremely soft even if carbon is produced, reducing the sliding resistance of the commutator sliding part and commutator segment.

High temperature with high probability of abnormal phenomenon in the above configuration,
At low humidity, an atmosphere matching the vapor pressure of (the chemical of the present invention) can be obtained in the motor case. The linear carbon bond or the side chain (the chemical of the present invention) having no benzene ring is strongly adsorbed on the metal surface by the polar group. This adsorption is stronger than the organic gas adsorbed by the van der Waals 'attractive force, except that the paraffins are adsorbed by the Van der Waals' attractive force.

By adsorbing (the chemical of the present invention), not only the commutator segment and brush with strong catalytic action made of Au, Pd, Pt, Ag, etc., but also that made of Cu, and the sintered carbon brush It also adsorbs on the surface and other metal surfaces, and prevents highly reactive gases (styrene monomer, toluene, etc.) from adhering to the surface. This is because (the chemical of the present invention) is strongly adsorbed with the exception of paraffins, compared with the organic gas adsorbed by the attraction of van der Waals such as styrene monomer and toluene. 7th
In the figure, A) product before test, B) test product in styrene monomer atmosphere, C) test product in toluene atmosphere,
D) shows the practical test results of the test product in the (chemicals of the present invention) atmosphere. In addition, those having (amino group) in the molecular structure have rust preventive power to protect the metal from corrosion.
Therefore, the metal component is stably protected for a long period of time. Moreover, in the case of small motors where the normal use environment atmosphere is -10 ℃ to + 60 ℃, the boiling point under one atmospheric pressure is from 100 ℃ to 2 ℃.
A temperature of about 50 ° C is particularly effective, and a temperature of about 300 ° C can be used. Listed under (Chemicals of the present invention) are 1) paraffins (example) (boiling point at 1 atm) 2.2.4 trimethylpentane ...... 99.2 ° C n-decane ...... 174.1 ° C n-dodecane 216.3 ° C tetradecane ...... 253.6 ℃ 2) Esters having one or more --COO-bonds (example) (boiling point under 1 atm) Dimethyl succinate …… 195 ℃ Ethyl octanoate …… 208 ℃ Diethyl fumarate …… 214 ℃ Diethyl decanoate …… 242 ℃ Diethyl adipate …… 245 ℃ 3) Alkyl amides having one or more -CONH- bonds (example) (boiling point at 1 atm) n-ethylacetamide 205 ℃ 4) Secondary amines having one or more —NH— bonds (example) (boiling point at 1 atm) dibutylamine …… 160 ° C 5) Tertiary amines having one or more —N≡ bonds (example) ) (Under one atmosphere , Etc. boiling point) tripropylamine ...... 157 ℃ tributylamine ...... 212 ℃.

The aforementioned (chemicals of the present invention) is adsorbed on the surfaces of the brush and the commutator segment to form a monomolecular film, so that the lubricity is extremely improved and the wear of the contact portion is significantly reduced.
(The result of the experiment is shown in FIG. 6.) The example shown in the result of the experiment will be described with reference to the motor of FIG. 5. This DC motor operating at 4.2V has an outer diameter of 30 mm and a height of 25 mm.
The current of 25mA flows through the circuit.

The polyester felt 16 provided inside this motor was washed and degreased with a polyfluoroethylene liquid, and impregnated with 0.1 to 0.6 gr of the chemical of the present invention, the chemical of the present invention gradually It was evaporated and a remarkable effect could be obtained. This felt can control the evaporation speed by changing the thickness and apparent specific gravity of the fiber. Even if a continuous foamed plastic or rubber sponge was used instead of this felt, a remarkable effect could be obtained.

The magnet 19 impregnated had a holding force of 0.1 to 0.3 g because the ferrite magnet was porous, and a remarkable effect could be obtained. In the same manner, plastic bracket 14 blended, plastic commutator base 5 blended, magnet wire 18 impregnated, metal bearing 20 oil blended, magnet 19 and Impregnated between the motor housings 15, blended with the anti-vibration rubber 9 shown in FIG. 2, blended with the anti-vibration rubber adhesive 8 shown in FIG. 2, c (chemical of the present invention)
There is a power to hold the, and a remarkable effect could be obtained.

Incidentally, in FIG. 6, A and B show rectified waveforms in an atmosphere of styrene monomer having unsaturated cyclic hydrocarbon, and A is
Rectified waveform before 60 ° C, 5% RH test, B is rectified waveform after 60 ° C, 5% RH 100 hours test. In addition, C and D show the confirmation results when about 10 μg of hydrocarbon (toluene) was adsorbed on the surface of the commutator segment. C is the rectified waveform before 60 ℃, 5% RH test, and D is 60 ℃, 5%. The rectified waveform after RH300 hour test. Furthermore, E and F show the confirmation results in the (chemicals of the present invention) atmosphere, E is the rectified waveform before the 60 ° C, 5% RH test, and F is the rectified waveform after the 60 ° C, 5% RH1500 hour test. .

Further, A in FIG. 7 shows the state of the surface of the commutator before the test, B shows the state after 100 Hr test in the atmosphere of unsaturated cyclic hydrocarbon (styrene monomer), and C shows the unsaturated cyclic hydrocarbon (toluene). Shows the state after the 300 Hr test when about 10 μg was adsorbed on the commutator segment surface, and D shows the state after the 1500 Hr test in the atmosphere of (the chemical of the present invention). In addition, both are 60 ℃, 5% RH
It has an atmosphere.

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

1) (Chemical agent of the present invention) is adsorbed on the surfaces of the brush and the commutator segment, which has a lubricating effect to prevent abnormal wear and rubbing damage of sliding parts.

2) Even if there is an organic gas having a benzene ring such as styrene monomer or toluene, the surface of the brush and commutator segment is protected by the film of the chemical of the present invention adsorbed on the surface, and the formation of black matter is minimal. Adjacent brushes, commutator and segment contact failure can be prevented. In addition, because contact failure does not occur, the generation of electrical noise is reduced, the speed of the small motor is stabilized due to unstable contact, and as a result, a small motor using a relatively low voltage of about 1V to 30V is used. This has the effect of reducing wow and flutter of the equipment used.

3) As a result of the above 1) and 2), the quality of the small motor is improved and the life can be greatly extended.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a conventional example, FIG. 2 is a diagram showing a configuration of a commutator sliding portion of a conventional example, and FIGS. 3, 4, and 5 are sectional views showing configurations of embodiments of the present invention. FIG. 6 is a diagram showing a rectified waveform of a comparative example and the present invention, and FIG. 7 is an explanatory diagram showing a state of a commutator segment surface of the comparative example and the present invention. 3 …… Commutator sliding part, 4 …… Commutator segment, 14 …… Bracket, 15 …… Housing, 16 ……
A felt impregnated with (the chemical of the present invention).

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Shigeru Kondo 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor ▲ Yoshi ▼ Shigeru Ta, 1006, Kadoma, Kadoma, Osaka In-house (56) References Japanese Patent Publication No. 32-2279 (JP, B1) Carbon Material Society of Japan, “Electrical Brushes and Their Usage”, Second Edition (Sho 52-3-1) Nikkan Kogyo Shinshinsha P. 149-150 Journal of Applied Physics 19 [1] (1948) P. 1-10

Claims (8)

[Claims] 1. A small motor having a brush mechanism section and a commutator, wherein the brush and the commutator slide, wherein the boiling point at one atmospheric pressure is in the range of 100 ° C. to 250 ° C. in the motor case, and No benzene ring 1) Paraffins 2) Esters having one or more -COO- bonds 3) Alkylamides having one or more -CONH- bonds 4) Having one or more -NH- bonds Secondary amines 5) A small motor having an atmosphere of at least one chemical selected from tertiary amines having one or more —N≡ bonds. 2. A small motor according to claim 1, wherein the chemicals are impregnated in felt or sponge arranged inside and near the motor case. 3. The small motor according to claim 1, wherein the chemical is impregnated in a field magnet installed in the motor case. 4. The small motor according to claim 1, wherein the chemical is blended in a plastic bracket that constitutes the motor case together with the motor housing. 5. The small motor according to claim 1, wherein the chemical is blended with a plastic commutator base. 6. The small motor according to claim 1, wherein the magnet wire is impregnated with the chemical. 7. The small motor according to claim 1, wherein the chemical is blended with oil of a metal bearing that supports a rotating shaft. 8. The small motor according to claim 1, wherein the chemical is impregnated between a magnet fixed to the inner surface of the motor housing constituting the motor case and the motor housing.