JPS5821273Y2 - Unidirectional microphone unit - Google Patents

Description

[Detailed description of the invention] This invention facilitates the positioning of component parts, and
The present invention relates to a microphone unit that can easily obtain stable unidirectivity.

A microphone unit with unidirectionality has a diaphragm attached to a voice coil attached to the front of a magnetic circuit configured in a pot shape with an annular yoke and a cylindrical magnet, and this voice coil is formed by the magnet and yoke. Generally, the diaphragm is located in an annular gap, and an acoustic passageway is provided on the back surface of the diaphragm to guide part of the incoming sound pressure.

Generally, the acoustic path of a unidirectional microphone having such a configuration is such that the magnet is cylindrical, and the center hole of the magnet is used as the acoustic path to introduce a portion of the incoming sound pressure to the back of the diaphragm. .

A unidirectional microphone with this configuration makes it easy to obtain directional characteristics because the rear sound pressure distribution is symmetrical with respect to the center axis of the microphone unit, but the magnet is expensive and it is separated by a coil. There were drawbacks such as difficulty in reaching the backside sound pressure to the outer part of the coil of the diaphragm.

In general, the diaphragm of a microphone needs to have high compliance in its axial direction, especially because of the requirement for low frequency reproduction.

It is well known that in order to maintain the compliance in the axial direction, the shape of the diaphragm may be increased by increasing the size of the corrugated portion provided on the outer periphery.

In the case of such a diaphragm, that is, a diaphragm whose outer peripheral area is larger than the center area, good directivity can be obtained in a unidirectional microphone using the above-mentioned cylindrical magnet. becomes difficult.

This invention solves these problems and provides a unidirectional microphone unit that can easily obtain stable unidirectionality.

One embodiment of this invention will be explained with reference to the drawings. Reference numeral 1 is a resin, and a guide portion 1a for a mounting screw hole 1a' for attaching the unit to an air chamber (not shown) provided on the back of the unit. , the mounting guide part of the ring yoke 8 (the mounting guide part 1b), the mounting guide part 1c of the diaphragm 3, the guide part 1d of the magnet 4, the acoustic passage 1e communicating with the hole 2a on the side surface of the yoke 2, and the hole on the bottom surface. The acoustic passage 1f communicating with the yoke 2b is integrally molded with the yoke 2.

By forming such a shape with resin 1,
The guide parts 1 a , 1 b t 1 c t 1 d are formed on perfect concentric circles.

The yoke 2 is cup-shaped, and has holes 2a on both sides thereof, and holes 2b, 2b on the bottom in a direction perpendicular to the holes 2a, 2a.

Further, the magnet 4 is attached to the inner center of the yoke 2.

Therefore, the passages extending from the back surface of the diaphragm 3 to both sides of the coil 5 are independently provided as an acoustic passage 1e leading to the hole 2a and an acoustic passage 1f leading to the hole 2b.

6 is a damper pasted on the outside of hole 2a, and 7 is a damper pasted on the outside of hole 2a.
This is a damper attached to the outside of b.

When the hole 2b is used by forming an air chamber of an appropriate volume (not shown) in the lower part of the microphone unit shown in the figure, the air existing in this chamber acts as an acoustic passage when the damper function is performed. .

8 is a ring-shaped yoke. This ring-shaped yoke 8 is provided with a notch 8a on its inner circumference, so that the acoustic passage 1e and the gap on the back of the diaphragm 3 are connected to the inner and outer portions separated by the coil 5. It's becoming easier to communicate.

In this microphone unit configured in this manner, the magnet 4 and the like can be easily positioned with respect to the yoke 2 by the resin 1.

That is, the magnet 4, which must be provided concentrically at the center of the yoke 2, is positioned by the magnet guide portion 1d formed in a part of the resin 1.

In order to obtain this guide portion 1d, the sound tube passage 1 e t
1 f is provided separately.

After that, when the ring-shaped yoke 8 and the diaphragm 3 are attached (see FIG. 4), they are also guided to the correct position and attached.

Also, a notch 8 formed on the inner circumference of the ring-shaped yoke 8
a and the dimensions of the acoustic path 1e can be set arbitrarily regardless of the acoustic path 1f, so that the back sound pressure introduced through the hole 2a is transmitted to the coil of the diaphragm 3 through the gaps on both sides of the coil 5 and the notch 8a. Since it can be applied appropriately to all the inner and outer back surfaces, good directivity can be easily and stably obtained.

[Brief explanation of the drawing]

Figure 1 is a plan view of an embodiment of this invention, Figure 2 is a cross-sectional view taken along ■--■ of Figure 1, Figure 3 is a cross-sectional view taken along ■-■ of Figure 1, and Figure 4 is a cross-sectional view of Figure 2. FIG. 3 is a cross-sectional view showing a partially exploded state. 1... Resin, 1a... Unit mounting screw guide, 1b... Ring yoke mounting guide, 1c... Vibration plate mounting guide part, 1d・
...Magnet guide part, 1 e, 1 f.
...Acoustic path, 2...Yoke, 2 a
t 2 b...hole, 3...diaphragm, 4
...Magnet, 5...Coil, 8.
...Ring-shaped yoke.

Claims (1)

[Scope of utility model registration request] The guide part of the unit mounting screw faces the unit mounting screw hole provided at the center of the bottom of the cup-shaped yoke with holes on the side and bottom surfaces, and the ring yoke located at the top of the cup-shaped yoke. the cup-shaped yoke from the rear surface of the diaphragm; What is claimed is: 1. A unidirectional microphone unit having an acoustic passage leading to a hole in a side surface and an acoustic passage leading to a hole in a bottom surface thereof, and integrally molded with the cup-shaped yoke from synthetic resin.