close

Вход

Забыли?

вход по аккаунту

?

DESCRIPTION JPH09200896

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JPH09200896
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
piezoelectric receiving unit such as a telephone which converts a voltage signal into an audio
signal.
[0002]
2. Description of the Related Art A conventional piezoelectric receiving unit is described below.
[0003]
FIG. 5 is a cross-sectional view of a conventional piezoelectric receiving unit, and FIG. 6 is a
partially enlarged cross-sectional view of an acoustic resistance hole of the back air case of FIG. 5
and a flow of air.
In FIG. 5, 1 is a front air chamber case, 2 is a sound emission hole, 3 is a front air chamber, 4 is a
back air chamber case, 5 is an acoustic resistance hole, 6 is a back air chamber, 7 is a
piezoelectric diaphragm, 8 is a piezoelectric diaphragm The lead wire 9 is an adhesive. In FIG. 6,
reference numeral 10 denotes the flow of air passing through the acoustic resistance hole 5.
[0004]
13-04-2019
1
When a voltage signal is applied to the piezoelectric diaphragm 7, the piezoelectric diaphragm 7
resonates to vibrate the air in the front air chamber 3 and the back air chamber 6, and the sound
waves are emitted. It is emitted from the hole 2 and the acoustic resistance hole 5. At this time,
the amount of air discharged from the back air chamber 6 through the acoustic resistance hole 5
is adjusted, but since the cross section of the opening of the acoustic resistance hole 5 is at a
right angle, the flow of air passing therethrough 10 had the problem that it was difficult to obtain
a piezoelectric receiving unit having a flat sound pressure frequency characteristic, as it was
disturbed or swirled and the amount of air discharged was not constant. SUMMARY OF THE
INVENTION It is an object of the present invention to provide a piezoelectric receiving unit
having flat sound pressure frequency characteristics.
[0005]
In order to achieve the above object, the opening area of the acoustic resistance hole formed in
the back air chamber case is made wider toward the back air chamber side and narrowed as
going to the outlet side.
[0006]
According to the present invention, the flow of air discharged from the back air chamber
becomes smooth when passing through the acoustic resistance hole and generation of vortices is
suppressed, and the amount of discharged air is also constant, high quality having flat sound
pressure frequency characteristics A piezoelectric receiver unit is obtained.
[0007]
The piezoelectric receiving unit according to a first aspect of the present invention is
characterized in that the opening area of the acoustic resistance hole is narrowed as the inside of
the back air chamber case widens toward the outlet side. It is a piezoelectric receiving unit, and
according to the present invention, the flow of air discharged from the back air chamber
becomes smooth when passing through the acoustic resistance hole, generation of vortices is
suppressed, and the amount of discharged air also becomes constant. .
[0008]
The acoustic resistance hole according to claim 2 of the present invention is characterized in that
the opening area inside the back air chamber case is 10 times to 180 times the opening area on
the outlet side, and is thereby discharged. It has the effect of smoothing the air flow.
13-04-2019
2
[0009]
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to
4.
(First Embodiment) FIG. 1 is an exploded perspective view of a piezoelectric receiving unit
according to a first embodiment of the present invention, FIG. 2 is a sectional view, and FIG. 3 is a
partially enlarged view of an acoustic resistance hole formed in a back air chamber case. FIG. 4
shows a cross-sectional view and the flow of air, and FIG. 4 is a diagram showing frequency
characteristics of the piezoelectric receiving unit of the present invention.
The component parts shown in FIGS. 1, 2 and 3 (the first embodiment) are basically the same as
the conventional component parts shown in FIG. 5 and FIG. Explanations will be simplified.
However, since the acoustic resistance holes 5 shown in FIG. 3 are different in shape but identical
in function, they are given the same numbers.
[0010]
In FIG. 2, the entire circumference of the piezoelectric diaphragm 7 is fixed by the adhesive 9
between the front air chamber case 1 having the sound emission hole 2 at the center and the
back air chamber case 4 in which the plurality of acoustic resistance holes 5 are formed. It
accommodates and the front air chamber 3 and the back air chamber 6 are formed.
The acoustic resistance hole 5 formed in the back air chamber case 4 has a wide open area inside
the back air chamber 6 as in the partial enlarged cross sectional view shown in FIG. There is.
When a voltage signal is applied to the piezoelectric diaphragm 7, the piezoelectric diaphragm 7
resonates, and the air in the front air chamber 3 and the back air chamber 6 is vibrated and
sound waves are emitted from the sound emission hole 2 and the acoustic resistance hole 5. . At
this time, the flow 10 of the air discharged from the acoustic resistance hole 5 formed for the
purpose of flattening the sound pressure frequency characteristic is cylindrical in shape of the
acoustic resistance hole 5 shown in FIG. Therefore, the flow 10 of the discharged air is disturbed
or swirled in the acoustic resistance hole 5, and the frequency characteristic is unlikely to be flat.
13-04-2019
3
On the other hand, in the case of the inverted conical shape shown in FIG. 3 (a) of the present
invention, this drawback is ameliorated and the air flow 10 discharged from the back air
chamber 6 becomes smooth and generation of vortices is suppressed, and the amount of
discharged air Also, a piezoelectric receiving unit having a flat sound pressure frequency
characteristic is obtained. As shown in FIGS. 3B and 3C, the shape of the acoustic resistance hole
5 is particularly restricted to an inverted conical shape as long as the inside of the back air
chamber 6 is wide and the outlet side is narrow. It is not a thing.
[0011]
(Second Embodiment) In the second embodiment of the present invention, an acoustic resistance
hole 5 having an inverted conical shape as shown in FIG. 3A is formed in the back air chamber
case 4, and the opening diameter inside the back air chamber 6. The diameter of the opening on
the outlet side is 1.7 mm, and the diameter of the opening on the back side of the acoustic
resistance hole 6 is 0.30 mm. The diameter of the opening on the outlet side was set to 0.15 mm,
16 pieces were provided, and the one having an opening area ratio of 4 was prepared, and the
frequency characteristics were compared. The results are shown in FIG. (A) of FIG. 4 shows an
aperture area ratio of 130 times, and (b) shows a sound pressure frequency characteristic of an
aperture area ratio of 4 times. As is clear from this, in the case of (b) as compared with (a),
fluctuation of sound pressure is observed between 500 Hz and 3 kHz, which is a high frequency.
This can be said to be due to the flow 10 of air discharged from the acoustic resistance hole 5.
[0012]
The purpose of the acoustic resistance hole 5 shown in FIG. 3 is to obtain a flat sound pressure
frequency characteristic as described above, and the desired purpose can be achieved with the
shape shown in the first embodiment, but the opening area ratio thereof Is smaller than 10 times
the inside and the outside of the back air chamber case 4, the air flow 10 is disturbed or a vortex
is generated in the acoustic resistance hole 5 as shown in FIG. On the other hand, if it is greater
than 180 times, at least 16 opening holes of the acoustic resistance hole 5 and at least 0.15 mm
diameter at the outlet of the exhaust chamber are necessary to secure the required sound
pressure level. Therefore, it can not be easily formed due to the positional relationship between
the adjacent acoustic resistance holes 5.
[0013]
13-04-2019
4
As described above, in order to smooth the air discharged from the back air chamber 6 when
passing through the acoustic resistance hole 5, the opening area ratio on the back air chamber
side is suppressed within the range of 10 times to 180 times. There is a need. Thereby, flattening
of the sound pressure frequency characteristic can be realized.
[0014]
As described above, according to the present invention, a sound resistance hole having an
opening area ratio of 10 times to 180 times on the inside and outside of the back air case
forming the back air chamber is formed. It is possible to provide a flat high-quality piezoelectric
receiving unit having pressure frequency characteristics.
[0015]
Brief description of the drawings
[0016]
1 is an exploded perspective view of a piezoelectric receiving unit according to an embodiment of
the present invention
[0017]
2 is a cross-sectional view of a piezoelectric receiving unit showing an embodiment of the
present invention
[0018]
FIGS. 3 (a) to 3 (c) are partial cross-sectional views of acoustic resistance holes formed in the
back air case of the present invention.
[0019]
Sound pressure frequency characteristic diagram of the piezoelectric receiving unit showing one
embodiment of the present invention
[0020]
Fig. 5 Cross-sectional view of a conventional piezoelectric receiving unit
13-04-2019
5
[0021]
Fig. 6 Partial cross-sectional view of the acoustic resistance hole formed in the back air case of
the conventional example
[0022]
Explanation of sign
[0023]
DESCRIPTION OF SYMBOLS 1 front air chamber case 2 sound emission hole 3 front air chamber
4 back air chamber case 5 acoustic resistance hole 6 back air chamber 7 piezoelectric diaphragm
8 lead wire 9 adhesive 10 air flow
13-04-2019
6
Документ
Категория
Без категории
Просмотров
0
Размер файла
13 Кб
Теги
jph09200896, description
1/--страниц
Пожаловаться на содержимое документа