JPS6024055Y2 - electroacoustic transducer - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an electroacoustic transducer using a piezoelectric vibrator.

Electroacoustic transducers such as piezoelectric buzzers that use piezoelectric vibrators have the advantage of not generating noise and being small and lightweight.
In recent years, it has begun to be used in various fields.

1 to 4 each show a conventional electroacoustic transducer.

FIG. 1 shows a piezoelectric element 2 attached to a flat diaphragm 1, and FIG. 2 shows a piezoelectric element 4 attached to the bottom of a dish-shaped diaphragm 3.

In FIG. 3, a piezoelectric vibrator 9 made by bonding a metal plate 7 and a piezoelectric element 8 is placed in a case 6 having a sound emitting hole 5.

FIG. 4 shows a piezoelectric vibrator 9 attached to the conical diaphragm 10 so as to close the opening at the top.

However, the conventional electroacoustic transducers as described above tend to be insufficient in terms of efficiency, frequency characteristics, mechanical strength, etc.

In view of the above points, the present invention has a structure in which the piezoelectric vibrator is supported in the middle of the inner tapered surface of the conical diaphragm with an opening at the top, and the taper angle is steeper at the back surface of the piezoelectric vibrator. The present invention aims to provide an electroacoustic transducer with improved performance.

Embodiments of the electroacoustic transducer according to the present invention will be described below with reference to the drawings.

FIG. 5 shows a first embodiment of the present invention.

In this figure, a conical diaphragm 20 has a top opening 22 in addition to a front opening 21, and the periphery of a unimorph piezoelectric vibrator 9 with a piezoelectric element 8 bonded to a metal plate 7 in the middle of an inner tapered surface 23. is supported and fixed.

As a result, a cavity 24 surrounded by the piezoelectric vibrator 9 and the conical diaphragm 20 is formed behind the piezoelectric vibrator 9.

Note that the material of the diaphragm 20 can be selected from paper, plastic, ceramic, etc. depending on the purpose.

According to this first embodiment, the empty chamber 2 is located behind the piezoelectric vibrator 9.
4 is formed, it is possible to improve efficiency, that is, to improve sound pressure, and it is possible to improve frequency characteristics.

In particular, it is possible to improve the characteristics in the high range.

Furthermore, since the piezoelectric vibrator 9 is attached inside the conical diaphragm 20, mechanical strength can be improved.
It is also easy to handle.

FIG. 6 shows a second embodiment of the invention.

In this figure, the conical diaphragm 30 has a front opening 3.
1 and a top opening 32, and a collar 3 at the front opening end.
It has 3 in one piece.

The periphery of the piezoelectric vibrator 9 is supported and fixed by the inner tapered surface 34 of the diaphragm 30, and a cavity 35 is formed behind the piezoelectric vibrator 9.

In this second embodiment, the mounting direction of the piezoelectric vibrator 9 is reversed from that in the first embodiment, but acoustically the piezoelectric vibrator 9 can be considered as one plate, and its front and back sides have different characteristics. Although unrelated, it is preferable to install it on the back side in order to avoid damage to the piezoelectric ceramic.

FIG. 7 shows a third embodiment of the present invention.

In this figure, a conical diaphragm 40 has a front opening 41 and a top opening 42, and a step as a piezoelectric vibrator mounting locking part is provided in the middle of an inner tapered surface 43 that expands parabolically toward the front opening. It has a section 44.

The periphery of the piezoelectric vibrator 9 is supported and fixed by its stepped portion 44, and a cavity 45 is formed behind the piezoelectric vibrator 9.

In this case, by appropriately setting the degree of expansion of the parabolic inner tapered surface 43, the efficiency can be further improved.

FIG. 8 shows a fourth embodiment of the present invention.

In this figure, a conical diaphragm 50 has a front opening 51 and a top opening 52, and further has a stepped portion 54 in the middle of an inner tapered surface 53 for mounting a piezoelectric vibrator.

As the piezoelectric vibrator, a bimorph piezoelectric vibrator 55 in which two piezoelectric elements are bonded together is used.
The peripheral edge of 5 is supported and fixed by the step 54, and a cavity 56 is formed behind it.

According to the fourth embodiment, since the bimorph piezoelectric vibrator 55 is used, it is easy to improve the sound pressure.

FIG. 9 shows a fifth embodiment of the present invention.

In this figure, a conical diaphragm 60 is formed of a honeycomb-like structure and has a front opening 61 and a top opening 62.

The periphery of the piezoelectric vibrator 9 is supported and fixed in the middle of the inner tapered surface 63.

As a result, a cavity 64 is formed behind the piezoelectric vibrator 9.

In this case, if the material of the diaphragm 60 is plastic, ceramic, etc., a honeycomb-like structure can be easily formed.

FIG. 10 shows a sixth embodiment of the present invention.

In this figure, the piezoelectric vibrator 70 is a unimorph piezoelectric vibrator in which a piezoelectric element 72 is bonded to a vibrating body 71 having a honeycomb structure, and the inner taper of a conical diaphragm 75 having a lower front surface 3 and a lower surface 4 is formed. It is supported and fixed in the middle of the surface 76.

In this case as well, if the material of the vibrating body 71 is plastic, ceramic, etc., a honeycomb-like structure can be easily formed.

In addition, in FIGS. 7, 8, and 9, a step portion as a locking portion for piezoelectric vibrator attachment is formed on the inner tapered surface of the diaphragm, but a protrusion, protrusion, etc. may be formed instead of the step portion. It may also be provided.

As explained above, according to the present invention, efficiency, frequency characteristics, and strength can be improved by supporting the piezoelectric vibrator in the middle of the inner tapered surface of the conical diaphragm with an opening at the top. Obtain an electroacoustic transducer.

[Brief explanation of drawings]

1 to 4 are side sectional views showing conventional electroacoustic transducers, FIG. 5 is a side sectional view showing a first embodiment of the electroacoustic transducer according to the present invention, and FIG. FIG. 7 is a side sectional view showing the third embodiment, and FIG. 8 is a side sectional view showing the fourth embodiment.
FIG. 9 is a side sectional view showing the fifth embodiment, and FIG. 10 is a side sectional view showing the sixth embodiment. 2.4, 8, 72...Piezoelectric element, 9...
・Unimorph piezoelectric vibrator, 20.40.50.60.7
5...Conical diaphragm, 21, 31, 41, 51
, 61.73...Front opening, 22, 32, 42
, 52.62.74...Top opening, 23. 3
4. 43.53, 63, 76...Inner tapered surface, 24, 35.45.56.64...Empty chamber, 30...Brim conical diaphragm.

Claims (4)

[Scope of utility model registration request] (1) An electroacoustic transducer characterized in that a piezoelectric vibrator is supported on the inner tapered surface of a conical diaphragm with an opening at the top, and the taper angle of the diaphragm is made steeper at the back surface of the piezoelectric vibrator. (2) Utility model registration claim 1, in which a locking portion for mounting a piezoelectric vibrator is formed on the inner tapered surface of the diaphragm.
The electroacoustic transducer described in Section 1. (3) The electroacoustic transducer according to claim 1 or 2, wherein the diaphragm is constituted by a honeycomb-like structure. (4) The electroacoustic transducer according to claim 1, which is a registered utility model, in which the back surface portion of the vibrator of the diaphragm is divided.