JP4095927B2 - Condenser microphone unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a condenser microphone unit, and more particularly to a locking means for pressing and fixing a fixed pole side to a diaphragm ring housed in a unit case.
[0002]
[Prior art]
The capacitor microphone unit has a capacitor element in which a diaphragm that vibrates by sound waves and a fixed electrode (back electrode) are opposed to each other through an air layer of a predetermined interval, and the capacitor element is assembled in a unit case. An example of this will be described with reference to FIGS. 3 is a front view of the condenser microphone unit, FIG. 4 is a sectional view taken along line AA, and FIG. 5 is an exploded sectional view.
[0003]
According to this, a cylindrical unit case 10 having a large number of sound introduction holes 12 on the front surface 11 as one surface and having the rear surface 13 side as the other surface opened is provided. The unit case 10 is made of metal, and in this example is made of brass.
[0004]
The sound introduction hole 12 includes a long slit 12a having a long length extending from the peripheral portion toward the center portion, and a short slit 12b having a shorter length than the long slit 12a. Are alternately arranged at equal intervals along the circumferential direction. A female screw 14 is formed on the inner peripheral surface of the unit case 10 on the rear surface 13 side.
[0005]
A front mesh 21, diaphragm ring 31, spacer ring 41, fixed pole 51, and insulating seat 61 made of synthetic resin are inserted into the unit case 10 in this order from the rear surface 13 side. A diaphragm (diaphragm) 32 that vibrates by sound waves is stretched on the surface of the diaphragm ring 31 that faces the fixed pole 51.
[0006]
The spacer ring 41 is made of a synthetic resin sheet formed in an annular shape, and secures an air layer at a predetermined interval between the diaphragm 32 and the fixed electrode 51. The fixed pole 51 is supported by an insulating seat 61 so as to be electrically insulated from the unit case 10 and the diaphragm 32. Although not shown, an electret film is formed on the fixed electrode 51. The insulating seat 61 is provided with an extraction electrode rod 62 for extracting a signal from the fixed pole 51.
[0007]
A lock ring 71 having a male screw 72 that engages with the female screw 14 is fitted into the rear surface 13 of the unit case 10, and the fixed electrode 51 is pressed to the diaphragm ring 31 side through the insulating seat 61 by this lock ring 71. Is attached, and the entire unit component including the diaphragm ring 31 and the fixed pole 51 is fixed. A metal ring is used as the lock ring 71. In this example, the lock ring 71 is made of brass, like the unit case 10.
[0008]
Although there is a model in which the edge on the rear surface 13 side of the unit case 10 is caulked and fixed without using the lock ring 71, fixing by the lock ring 71 is mainly applied to a microphone designed with emphasis on performance. Yes.
[0009]
That is, when an excessive stress is applied to the unit parts, displacement occurs. Even if the displacement is small, the performance may be deteriorated. Therefore, in the microphone in which performance is important, the stored item is fixed with the minimum necessary stress while adjusting the pressing force by the lock ring 71. Like to do.
[0010]
[Problems to be solved by the invention]
However, the above conventional example has the following problems. That is, since the female screw 14 of the unit case 10 and the male screw 72 of the lock ring 71 are both formed by cutting, metal powder is generated by rubbing during the screwing.
[0011]
For example, when the metal powder is sandwiched between the diaphragm 32 and the spacer ring 41 or between the spacer ring 41 and the fixed electrode 51, air leakage occurs in the air layer between the diaphragm 32 and the fixed electrode 51. And the directional frequency response is degraded. Further, when metal powder enters between the fixed pole 51 and the inner peripheral surface of the unit case 10, electrical leakage occurs from the fixed pole 51, which causes noise.
[0012]
Accordingly, an object of the present invention is to prevent performance deterioration due to metal powder generated by screwing of a lock ring when a unit part accommodated in a unit case is pressed and fixed by a lock ring with a predetermined stress. is there.
[0013]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention is a unit case comprising a metal cylindrical body having a sound introduction hole on one surface and the other surface being opened, and having an internal thread on the inner peripheral surface on the open end side. In the unit case, a diaphragm ring having a diaphragm from the open end side toward the sound introduction hole, a spacer ring, a fixed pole for the diaphragm and an insulating seat are inserted in this order, and A metal lock ring having a male screw threadedly engaged with the female screw is attached to the back surface of the insulating seat, and the fixed electrode is pressed and fixed to the diaphragm ring side with a predetermined pressure by the lock ring via the insulating seat. In the condenser microphone unit, an elastic ring made of a rubber material compressed by the lock ring is provided between the insulating seat and the lock ring. It is characterized in that it is so.
[0014]
According to this configuration, even if the metal powder is generated by rubbing when the lock ring is screwed, the elastic ring is interposed between the insulating seat and the lock ring. However, if more certainty is desired, a ring housing groove into which a part of the outer periphery of the elastic ring is fitted on the inner surface of the unit case is annularly adjacent to the end of the female screw. It is preferable to form. In addition, as the rubber material used for the elastic ring, a silicon rubber material excellent in electrical insulation is preferably employed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a sectional view showing the internal structure of a condenser microphone unit according to the present invention. FIGS. 2A and 2B are sectional views of a unit case and an elastic ring provided in the condenser microphone unit. In the description of this embodiment, the same reference numerals are used for components that may be regarded as the same as or the same as those of the conventional example described above.
[0016]
This condenser microphone unit also includes a cylindrical unit case 10 made of, for example, brass. As shown in FIG. 3, the front surface 11 of the unit case 10 may be provided with a number of sound introduction holes 12 including long slits 12a and short slits 12b.
[0017]
The rear surface 13 side of the unit case 10 is opened to insert unit parts, and an internal thread 14 is formed on the inner peripheral surface by cutting. According to the present invention, as shown in FIG. In this manner, a ring housing groove 15 is formed in an annular shape adjacent to the female screw 14 and inside thereof, and an elastic ring 81 shown in FIG.
[0018]
The assembly procedure will be described. First, the front mesh 21 is inserted into the unit case 10 from the rear surface 13 side to the front surface 11 side. A wire mesh can be used for the front mesh 21. Next, the diaphragm ring 31 on which the diaphragm 32 is stretched is inserted with the diaphragm 32 facing backward, and the spacer ring 41 is disposed around the diaphragm 32.
[0019]
The extraction electrode rod 62 is inserted into the insulating seat 61, the fixed pole 51 is attached to the front surface thereof, and the insulating seat 61 is inserted into the unit case 10 with the fixed pole 51 facing the diaphragm 32. Then, after mounting the elastic ring 81 in the ring housing groove 15, a lock ring 71 having an external thread 72 on the outer periphery is screwed into the female eye 14 of the unit case 10, and the elastic ring 81 is tightened so as to be appropriately compressed.
[0020]
In this example, since the lock ring 71 is also made of brass like the unit case 10, metal powder is generated by rubbing at the time of screwing, but since the periphery of the insulating seat 61 is sealed by the elastic ring 81, the metal powder Does not enter the fixed pole 51 side.
[0021]
Therefore, the directional frequency response is deteriorated due to air leakage of the air layer between the diaphragm 32 and the fixed pole 51, which has been a problem in the conventional example, or between the fixed pole 51 and the inner peripheral surface of the unit case 10. Problems such as noise generation due to electrical leakage caused by metal powder are solved. The elastic ring 81 is formed of a natural or synthetic rubber material, and a silicon rubber material is preferably employed from the viewpoint of electrical insulation.
[0022]
Further, since the elastic ring 81 is compressed by tightening the lock ring 71 and spreads in the inner diameter direction, airtightness between the unit case 10 and the insulating seat 61 can be ensured. Furthermore, since the tightening force of the lock ring 71 is applied to the unit parts including the diaphragm ring 31 and the fixed pole 51 via the elastic ring 81, the tightening force can be made uniform and stable.
[0023]
In the above embodiment, the ring housing groove 15 into which a part of the outer peripheral side of the elastic ring 81 is fitted is formed in the unit case 10, but in some cases, without forming the ring housing groove 15, The elastic ring 81 may have the same diameter as the insulating seat 61 and may be directly disposed on the back side of the insulating seat 61, and such an aspect is also included in the present invention.
[0024]
Moreover, although the unit case 10 and the lock ring 71 are made of brass, other metal materials such as aluminum may be used. Further, the present invention is not limited to the electret type condenser microphone provided with the electret film on the fixed electrode 51.
[0025]
【The invention's effect】
As described above, according to the present invention, the fixed ring supported by the diaphragm ring having the diaphragm, the spacer ring, and the insulating seat is provided in the unit case made of the metal cylindrical body having the sound introduction hole on the front surface. In a condenser microphone unit that contains unit parts, and is fixed with a clamping force of a metal lock ring that is screwed from the rear side of the unit case toward the insulation seat, between the insulation seat and the lock ring. In addition, since an elastic ring made of a rubber material compressed by the lock ring is interposed, it is possible to prevent performance degradation of the condenser microphone due to metal powder generated by screwing of the lock ring.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the internal structure of a condenser microphone unit according to the present invention.
2A is a cross-sectional view showing a unit case included in the condenser microphone unit, and FIG. 2B is a cross-sectional view showing an elastic ring included in the condenser microphone unit.
FIG. 3 is a front view showing a conventional condenser microphone unit.
4 is a cross-sectional view taken along line AA in FIG.
FIG. 5 is an exploded cross-sectional view of the conventional condenser microphone unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Unit case 11 Front surface 12a, 12b of unit case Sound introduction hole 13 Rear surface 14 of unit case Female female 15 Ring storage groove 21 Front mesh 31 Diaphragm ring 32 Diaphragm 41 Spacer ring 51 Fixed pole 52 Lead electrode rod 61 Insulating seat 71 Lock Ring 72 Male thread 81 Elastic ring

Claims (3)

The unit case is composed of a metal cylinder having a sound introduction hole on one side and the other side being open, and has an internal thread on the inner peripheral surface on the open end side. A diaphragm ring having a diaphragm from the end side toward the sound introduction hole, a spacer ring, a fixed pole for the diaphragm and an insulating seat are inserted in this order, and are screwed onto the female screw on the back surface of the insulating seat. In a condenser microphone unit to which a metal lock ring having a male screw is attached, and the fixed pole is pressed and fixed to the diaphragm ring side with a predetermined pressure by the lock ring via the insulating seat.
A condenser microphone unit, wherein an elastic ring made of a rubber material compressed by the lock ring is interposed between the insulating seat and the lock ring. 2. The condenser microphone unit according to claim 1, wherein a ring housing groove into which a part of the outer periphery of the elastic ring is fitted is formed on the inner surface of the unit case in an annular shape adjacent to the end of the female screw. 3. The condenser microphone unit according to claim 1, wherein the elastic ring is made of a silicon rubber material.

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