JP2004343368A - Condenser microphone unit - Google Patents

Abstract

An object of the present invention is to prevent the performance of a condenser microphone from being deteriorated due to metal powder generated by screwing a lock ring together with a unit case and a lock ring.
A unit component including a diaphragm ring having a diaphragm, a spacer ring, and a fixed pole supported by an insulating seat, in a metal unit case having sound introduction holes on the front surface. Are housed, and the unit components of the condenser microphone unit are fixed by a tightening force of a metal lock ring 71 screwed from the rear side of the unit case 10 toward the insulating seat 61. Between them, an elastic ring 81 made of a rubber material compressed by the lock ring 71 is interposed.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a condenser microphone unit, and more particularly, to a lock unit that presses and fixes a fixed pole side to a diaphragm ring housed in a unit case.
[0002]
[Prior art]
The condenser microphone unit has a capacitor element in which a diaphragm vibrated by sound waves and a fixed pole (back pole) are opposed to each other via an air layer at a predetermined interval, and the capacitor element is assembled in a unit case. One example will be described with reference to FIGS. FIG. 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 a front surface 11 as one surface and an open rear surface 13 side as the other surface is provided. The unit case 10 is made of metal, and in this example, made of brass.
[0004]
Further, 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 on the rear surface 13 side of the unit case 10.
[0005]
Inside the unit case 10, a front mesh 21, a diaphragm ring 31, a spacer ring 41, a fixed pole 51, and an insulating seat 61 made of synthetic resin are inserted in this order from the rear surface 13 side. A diaphragm (diaphragm) 32 that vibrates by sound waves is stretched on a surface of the diaphragm ring 31 facing the fixed pole 51.
[0006]
The spacer ring 41 is formed of a synthetic resin sheet formed in an annular shape, and secures a predetermined gap of an air layer between the diaphragm 32 and the fixed pole 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, the fixed pole 51 is formed with an electret film. 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 screwed with the female screw 14 is fitted into the rear surface 13 of the unit case 10, and the fixed ring 51 is pressed by the lock ring 71 via the insulating seat 61 toward the diaphragm ring 31 with a predetermined pressing force. Is applied, and the entire unit component including the diaphragm ring 31 and the fixed pole 51 is fixed. A metal ring is used for the lock ring 71, and in this example, the lock ring 71 is made of brass similarly to the unit case 10.
[0008]
Note that there is a model in which the edge on the rear surface 13 side of the unit case 10 is fixed by caulking without using the lock ring 71. However, the fixing by the lock ring 71 is mainly applied to a microphone designed with emphasis on performance. I have.
[0009]
That is, when an excessive stress is applied to the unit components, displacement occurs. Even if the displacement is small, the performance may be degraded. Therefore, in microphones where performance is important, the above-mentioned items are fixed with the minimum necessary stress while adjusting the pressing force by the lock ring 71. I am trying to do it.
[0010]
[Problems to be solved by the invention]
However, according to the above conventional example, there are 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, rubbing at the time of screwing generates metal powder.
[0011]
When the metal powder is sandwiched between, for example, the diaphragm 32 and the spacer ring 41 or between the spacer ring 41 and the fixed pole 51, air leakage occurs in an air layer between the diaphragm 32 and the fixed pole 51. And degrades the directional frequency response. Further, if metal powder enters between the fixed pole 51 and the inner peripheral surface of the unit case 10, electric leakage occurs from the fixed pole 51, which causes noise.
[0012]
Therefore, an object of the present invention is to prevent performance deterioration due to metal powder generated by screwing of a lock ring when a predetermined stress is applied to a unit component housed in a unit case by applying a predetermined stress by a lock ring. is there.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a unit case comprising a metal cylinder having a sound introduction hole on one surface and an open other surface, and having a female screw on an inner peripheral surface on an open end side thereof. In the unit case, a diaphragm ring having a diaphragm from the open end side thereof toward the sound introduction hole, a spacer ring, a fixed pole for the diaphragm and an insulating seat are inserted in this order, A metal lock ring having a male screw screwed with the female screw is attached to the back surface of the insulating seat, and the fixed ring is pressed and fixed with a predetermined pressure to the diaphragm ring side via the insulating seat by the lock ring. 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 due to the rubbing at the time of screwing the lock ring, the elastic ring is interposed between the insulating seat and the lock ring. However, if more certainty is required, a ring storage groove into which a part of the outer periphery of the elastic ring is fitted is formed in the inner surface of the unit case in an annular shape adjacent to the end of the female screw. Preferably, it is formed. As the rubber material used for the elastic ring, a silicon rubber material having excellent electrical insulation properties is preferably employed.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view showing the internal structure of a condenser microphone unit according to the present invention, and 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 in the conventional example described above.
[0016]
This condenser microphone unit also includes a cylindrical unit case 10 made of, for example, brass. A large number of sound introduction holes 12 including a long slit 12a and a short slit 12b may be provided in the front surface 11 of the unit case 10, as shown in FIG.
[0017]
The rear surface 13 side of the unit case 10 is open for inserting a unit component, and a female screw 14 is formed on the inner peripheral surface thereof by cutting. According to the present invention, it is shown in FIG. As described above, a ring storage groove 15 is formed annularly inside and adjacent to the female screw 14, and an elastic ring 81 shown in FIG. 2B is mounted in the ring storage groove 15.
[0018]
The assembling 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 arranged around the diaphragm 32.
[0019]
The extraction electrode rod 62 is inserted through the insulating seat 61, and the fixed pole 51 is attached to the front surface thereof. The fixed pole 51 faces the diaphragm 32 and the insulating seat 61 is inserted into the unit case 10. Then, after the elastic ring 81 is mounted in the ring housing groove 15, the lock ring 71 having the male screw 72 on the outer periphery is screwed into the female female 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. However, since the periphery of the insulating seat 61 is sealed by the elastic ring 81, the metal powder is formed. Does not enter the fixed pole 51 side.
[0021]
Therefore, the directional frequency response is degraded due to air leaking from the air layer between the diaphragm 32 and the fixed pole 51, which is a problem in the above-described conventional example, and the gap between the fixed pole 51 and the inner peripheral surface of the unit case 10 is reduced. Problems such as generation of noise due to electric leakage caused by the metal powder are eliminated. The elastic ring 81 is formed of a natural or synthetic rubber material, but from the viewpoint of electrical insulation, a silicon rubber material is preferably employed.
[0022]
Further, since the elastic ring 81 is compressed and expanded in the inner diameter direction by the tightening of the lock ring 71, the airtightness between the unit case 10 and the insulating seat 61 can be secured. Furthermore, since the tightening force of the lock ring 71 is applied to the unit components 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-described 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 embodiment is also included in the present invention.
[0024]
Although brass is used for the unit case 10 and the lock ring 71, other metal materials such as aluminum may be used. Further, the present invention is not limited to the electret condenser microphone in which the fixed pole 51 includes the electret film.
[0025]
【The invention's effect】
As described above, according to the present invention, a fixed electrode supported by a diaphragm ring having a diaphragm, a spacer ring and an insulating seat is provided in a unit case made of a metal cylinder having a sound introduction hole on a front surface. In the condenser microphone unit in which the unit parts including the unit are stored and the unit parts are fixed by the fastening force of a metal lock ring screwed from the rear side of the unit case toward the insulating seat, the gap between the insulating seat and the lock ring is provided. In addition, by interposing an elastic ring made of a rubber material compressed by the lock ring, 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 sectional view showing the internal structure of a condenser microphone unit according to the present invention.
2A is a cross-sectional view illustrating a unit case included in the condenser microphone unit, and FIG. 2B is a cross-sectional view illustrating an elastic ring included in the condenser microphone unit.
FIG. 3 is a front view showing a conventional condenser microphone unit.
FIG. 4 is a sectional view taken along line AA of FIG. 3;
FIG. 5 is an exploded sectional view of the conventional condenser microphone unit.
[Explanation of symbols]
Reference Signs List 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 Vibrating plate 41 Spacer ring 51 Fixed pole 52 Leading electrode rod 61 Insulation seat 71 Lock Ring 72 Male screw 81 Elastic ring

Claims (3)

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

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