JP3874928B2 - Dynamic microphone - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dynamic microphone, and more particularly to a rust prevention technique for a voice coil attached to the diaphragm.
[0002]
[Prior art]
The dynamic microphone includes a movable part on the diaphragm (diaphragm) side having a voice coil for power generation, and a fixed part on the magnetic circuit side that acts magnetically on the voice coil. FIG. 1 shows a rear view of the diaphragm on which the voice coil is attached, and FIG. 2 shows a configuration on the magnetic circuit side together with the diaphragm.
[0003]
As a general configuration, this type of diaphragm 1 includes a center dome portion 11 at the center, a voice coil attachment portion 13 (see FIG. 2) on the outer periphery of which a voice coil 12 is attached, and a voice. It is formed concentrically from an edge part 14 formed in a convex shape on the outer peripheral part of the coil attaching part 13 and an edge fixing part 15 on the outer peripheral part of the edge part 14, and each of these members is composed of, for example, polyethylene, polyester or the like It is manufactured integrally from a resin material.
[0004]
On the other hand, the magnetic circuit 2 on the fixed portion side is connected to the permanent magnet 21 magnetized in the thickness direction, the center pole piece 22 placed on one pole side thereof, and the other pole side of the permanent magnet 21. And a bottomed cylindrical yoke 23 that forms a magnetic gap G having a predetermined width with the center pole piece 22.
[0005]
The voice coil 12 is inserted into the magnetic gap G so as to vibrate together with the diaphragm 1 in a state of being attached to the diaphragm 1, and a pair of lead wires 121 are drawn to the outside through the bottom of the edge fixing portion 15, The portion is soldered to a relay terminal plate 24 provided on the outer surface side of the yoke 23, for example.
[0006]
By the way, dynamic microphones are used in various places, but unidirectional ones are often used exclusively for karaoke, stage or coverage.
[0007]
Since the unidirectional dynamic microphone is a mass control system, the frequency response can be flattened in a frequency band equal to or higher than the low-band resonance frequency. On the other hand, however, vibration noise is generated in the vicinity of the low-band resonance frequency when the microphone is tapped or rubbed by hand.
[0008]
There are various methods for reducing such vibration noise caused by solid propagation. One of them is a method for reducing the mass of the movable part. Most of the mass on the movable part side is occupied by the voice coil 12.
[0009]
Usually, a copper wire is used for the wire of the voice coil 12, but by using an aluminum wire having a light specific gravity, the mass on the movable part side can be further reduced. However, aluminum cannot be soldered.
[0010]
Then, the wire which coat | covered copper on the aluminum core material, and what is normally called CCAW wire (copper clad aluminum wire) are used. The CCAW line was said to be difficult to be thinned, but the wire manufacturer has been gradually miniaturized by technological development. At the present stage, the wire diameter is 0.03 mm, the weight is 0.0038 g / m, and the resistance value is 36. 4 (20 ° C., Ω / m) can be exemplified.
[0011]
In addition, on the surface of this CCAW wire, for the purpose of electrical insulation between the wires and shape retention when coiled, an insulation film having a thickness of about 0.003 mm on the copper coating, A fused film having a thickness of about 0.003 mm is formed.
[0012]
[Problems to be solved by the invention]
However, the CCAW line has the following unique problems. That is, in the CCAW line, although the insulating film and the fusion film are provided on the copper coating as described above, since the film thickness is extremely thin, the insulation film and the fusion film are easily broken. I can't deny that.
[0013]
In particular, in the voice coil 12, the pulling force and the bending force when the lead wire 121 is routed to the relay terminal plate 24 are concentrated on the lead portion 12A (see FIG. 1) of the lead wire 121. The insulating film and the fused film are easily broken at 12A. In addition, when the lead wire 121 is soldered to the relay terminal plate 24, the insulating film and the fused film are destroyed by the solder heat.
[0014]
And if moisture adheres to the wire part where these films have been destroyed due to condensation, local batteries are generated at the part where copper and aluminum dissimilar metals are joined, and aluminum, which is a base metal in terms of potential, corrodes. It becomes nonconductor.
[0015]
Such corrosion of the aluminum core material cannot be discriminated from the appearance, and the cause is not until the resistance value of the voice coil 12 is increased and the output level of the microphone is lowered or noise such as contact noise is generated. It was something that could be pinpointed and could not be solved.
[0016]
The present invention has been made to solve such problems, and its purpose is to effectively prevent corrosion of aluminum, which is the core of the CCAW wire, and maintain the power generation capability of the voice coil as designed. Another object is to provide a highly reliable dynamic microphone.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, the present invention comprises a movable part including a diaphragm to which a voice coil for power generation is attached, and a fixed part including a magnetic circuit having a magnetic gap into which the voice coil is inserted. As the coil, a CCAW wire in which an aluminum core material is coated with copper and an insulating film and a fusion film are further formed on the copper coating is used, and the lead wire is provided on the fixed portion side. In the dynamic microphone soldered to the relay terminal plate, the lead-out portion of the coil lead wire of the voice coil (CCAW wire) and the portion soldered to the relay terminal plate of the coil lead wire are moisture-proof. A coating film made of a fluororesin as a material is formed.
[0018]
In the present invention, before attaching the voice coil to the diaphragm or after attaching the voice coil to the diaphragm, a fluorine resin film is formed on the lead-out portion of the coil lead wire. Further, Oite soldering箇plants with respect to the relay terminal plate of the coil lead wire forms a fluorine-based resin film after soldering.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to the embodiment. Since the basic configuration of the dynamic microphone is the same as that of FIGS. 1 and 2 described above, these drawings are used. .
[0020]
Although the present invention includes an aspect in which the moisture-proof material is formed over the entire length of the CCAW wire, it is preferably wound around the voice coil 12 and then applied to the lead-out portion 12A of the lead wire 121. The application to the lead-out portion 12A may be performed before the voice coil 12 is attached to the diaphragm 1 or after the voice coil 12 is attached to the diaphragm 1.
[0021]
Further, according to the present invention, the moisture-proof material is also applied to the soldered portion of the lead wire 121 to the relay terminal plate 24. The application to the soldering portion is performed after the soldering.
[0022]
In the present invention, a strong hydrophobic fluororesin using an alternative chlorofluorocarbon as a solvent is preferably used as the moisture-proof material. Examples thereof include polyvinyl fluoride, polyvinylidene fluoride, polytrifluoroethylene, polytetrafluoroethylene, and a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether.
[0023]
Such a fluorine-based resin is preferably formed as a film by applying a solution dissolved in a solvent and evaporating the solvent, and the thickness of the film can be exemplified by about 0.001 mm. . Since it is such a thickness, it does not interfere with the acoustic function of the microphone.
[0024]
【Example】
Example 1
A resistance value of 36.4 Ω / m (20 ° C.) obtained by coating an aluminum core material having a wire diameter of 0.03 mm with copper and further forming an insulation film and a fusion film each having a thickness of 0.003 mm on the copper coating. ) CCAW line is prepared, and the insulation film and the fusion film are removed from a part of the CCAW line, and the product name “Fluorobarrier” manufactured by IG Co., Ltd. is used as the fluorine-based resin film on the removed part. A film having a thickness of 0.001 mm was formed.
[0025]
<Comparative example 1>
The same CCAW wire as in Example 1 was used, and a part of the insulating film and the fused film were removed and left as it was.
[0026]
Next, the CCAW wires of Example 1 and Comparative Example 1 were sprayed with 5 ± 1% (weight ratio) of saline at a concentration of 35 ± 2 ° C. and left at 35 ± 2 ° C. for 24 hours. 1, the resistance value of the wire did not change, but in the case of Comparative Example 1, the resistance value of the wire increased to 2 kΩ / m (20 ° C.).
[0027]
Example 2
The CCAW line of the first embodiment is used for the voice coil 12 of the dynamic microphone shown in FIGS. 1 and 2, the coil lead line 121 is drawn outside through the edge fixing portion 15, and the end thereof is connected to the relay terminal plate 24. Soldered. And the fluorine resin film similar to Example 1 was formed in the soldering surface.
[0028]
<Comparative example 2>
In Example 2, it was the same as Example 2 except that the fluororesin film was not formed on the soldered surface.
[0029]
Then, 5 ± 1% (weight ratio) of saline is sprayed on the soldered portions of Example 2 and Comparative Example 2 at a concentration of 35 ± 2 ° C. and left at 35 ± 2 ° C. for 24 hours. As a result, no noise was generated in Example 2, but noise was generated in Comparative Example 2.
[0030]
【The invention's effect】
As described above, according to the present invention, the CCAW wire protective coating (insulating coating and fusion coating) as the voice coil wire is easily broken (the lead-out portion of the coil lead wire of the voice coil), and the destruction. By forming a fluorine-based resin film on the soldered part ( the part soldered to the relay terminal plate of the coil lead wire), it is possible to prevent moisture from adhering, thus preventing the aluminum core material from corroding. It can be effectively prevented.
[0031]
As a result, the resistance value of the voice coil can be prevented from increasing for many years. Therefore, it is possible to provide a highly reliable dynamic microphone that does not cause a reduction in the output of the microphone or generate noise.
[Brief description of the drawings]
FIG. 1 is a rear view of a side to which a voice coil of a diaphragm used in a dynamic microphone is attached.
FIG. 2 is a cross-sectional view schematically showing a general configuration of a dynamic microphone having the diaphragm.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Diaphragm of movable part 11 Dome part 12 Voice coil 121 Coil lead wire 13 Voice coil attachment part 14 Edge part 15 Edge fixing part 2 Magnetic circuit of fixing part side 21 Permanent magnet 22 Center pole piece 23 Yoke 24 Relay terminal board

Claims (1)

A movable part including a diaphragm to which a voice coil for power generation is attached; and a fixed part including a magnetic circuit having a magnetic gap into which the voice coil is inserted. As the voice coil, an aluminum core is covered with copper. A dynamic microphone in which a CCAW wire in which an insulating coating and a fusion coating are further formed on the copper coating is used, and the lead wire is soldered to the relay terminal plate provided on the fixed portion side In
A coating film made of a fluorine-based resin as a moisture-proof material is formed on the lead portion of the coil lead wire of the voice coil (CCAW wire) and the soldered portion of the coil lead wire to the relay terminal plate. Dynamic microphone characterized by

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