JPH0715637B2 - Piezoelectric sounder - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric sounder such as a piezoelectric buzzer that applies a driving voltage to a piezoelectric element and outputs a sound.

2. Description of the Related Art FIG. 6 is a typical prior art sectional view of a piezoelectric buzzer as an example of a piezoelectric sounder. The piezoelectric buzzer 1 has a bottomed cylindrical resin case 2 having an opening at one end (lower end in FIG. 6), a cover 3 attached to cover the opening of the resin case 2, and arranged inside the resin case 2. The vibrating plate 5 in which the piezoelectric element 4 is attached to the surface of the cover 3 side, the metal terminal 6a electrically connected to the piezoelectric element 4, and the metal terminal 6b electrically connected to the vibrating plate 5 are provided. Have. A sound emitting hole 7 is formed in the bottom of the resin case 2, and a step portion 8 with which the peripheral edge of the diaphragm 5 abuts is formed. The vibrating plate 5 has its peripheral edge portion fixed by the step portion 8 and the upper end surface of the cover 3. Thereby, the vibration space 5 and the resin case 2 form a resonance space 9. Further, one end of the metal terminal 6a is in the space 9a defined by the cover 3 and the diaphragm 5, and elastically abuts the piezoelectric element 4 by its elastic force. The other end is pulled out to the outside through the insertion hole 10a of the cover 3. Similarly, the other metal terminal 6b has one end in the space 9a defined by the cover 3 and the diaphragm 5 and elastically abuts the diaphragm 5 by its elastic force, and the other end It is pulled out through the insertion hole 10b of the cover 3.

In such prior art, it is necessary to insert the diaphragm 5 into the case 2 and then insert the cover 3 into the case 2 for assembly. Therefore, it is necessary to insert and fix the metal terminals 6a and 6b into the cover 3 in advance. There must be. Therefore, the assembly work becomes complicated. Further, this prior art requires the cover 3, and accordingly the number of parts is increased accordingly.

FIG. 7 is a sectional view of another prior art piezoelectric buzzer. This piezoelectric buzzer 11 has a cylindrical resin case 12 with an opening on one side, and an opening of the resin case 12 as well as the resin case 12
The vibration plate 14 with the piezoelectric element 13 attached to the outer surface of the
And a metal terminal 15a electrically connected to the piezoelectric element 13,
And a metal terminal 15b electrically connected to the metal plate 14. A sound emitting hole 7a is formed at the bottom of the resin case 12. The vibrating plate 14 is fixed to the resin case 12 by an adhesive 19 at the peripheral edge thereof, whereby the vibrating plate 14 and the resin case 12 form a resonance space 16. Also,
The portion 17a of the metal terminal 15a is pressed into the side wall of the resin case, and the portion 18a of the metal terminal 15a is the resin case.
It extends toward the inner side of 12, and its tip is soldered and fixed to the piezoelectric element 13. The other metal terminal 15b also has the same structure as the metal terminal 15a, and the portion 17a
Is pressed into the side wall of the resin case 12, and the portion 18b extends toward the inner side of the resin case 12, and its tip is soldered and fixed to the diaphragm 14.

In such a prior art, although the number of parts is reduced as compared with the prior art shown in FIG. 6 because the cover 3 is not used, the fixing of the diaphragm 14 to the resin case 12 requires the use of an adhesive, Further, since the contacts of the piezoelectric elements 13 and the vibration plate 14 of the metal terminals 15a and 15b are exposed to the outside, soldering is required to prevent catching and dust entering during the assembly work. The number of processing steps is increased.

SUMMARY OF THE INVENTION Problems to be Solved by the Invention In summary, in the prior art, the cost is high due to the increase in the number of parts, the complexity at the time of assembly work, the increase in the number of steps, etc., and such a point becomes a problem. Was there.

An object of the present invention is to solve the above-mentioned technical problems, to reduce the number of parts, to eliminate the need for complicated processing steps, to enable mounting work from one direction, and to realize cost reduction. It is to provide a piezoelectric sounder.

Means for Solving the Problems The present invention includes a diaphragm having a piezoelectric element attached to one surface thereof, and a resin case for fixing the diaphragm, and a metal electrically connected to the piezoelectric element and the diaphragm. A piezoelectric sounder configured to apply a drive voltage to a piezoelectric element via a terminal includes a diaphragm having a piezoelectric element attached to one surface thereof, and a resin case for fixing the diaphragm. In a piezoelectric sounder configured to apply a drive voltage to a piezoelectric element through a pair of metal terminals electrically connected to each other, the resin case is a bottomed tubular shape having an opening at one end, A pair of terminal receiving grooves are formed on the side wall,
The diaphragm is attached to the resin case opening so as to close the opening of the resin case, and forms a sound emitting hole between the diaphragm and the terminal receiving groove, and the metal terminal has the terminal receiving groove. And one end of which is extended to the outside, the other end of which is extended into the resonance space formed by the vibrating plate and the resin case, and is elastically attached to the piezoelectric element and the vibrating plate, respectively. The feature is that they are abutted.

Operation According to the above configuration, the metal terminal is attached to the resin case by inserting the terminal receiving groove formed in the side wall of the resin case, and by fixing the diaphragm to the resin case in such a state, the present invention can be realized. Such a piezoelectric sounder can be assembled. Therefore, only the working process from one direction is required, and since complicated bonding and soldering processes are not required, it is possible to easily realize the automatic assembling work. Also,
Since it is not necessary to attach a cover or the like to the resin case, the number of parts can be reduced.

EXAMPLE FIG. 1 is a sectional view of a piezoelectric buzzer as an example of the piezoelectric sounder according to the present invention, FIG. 2 is a plan view seen from the arrow A side of FIG. 1, and FIG. It is the side view seen from the Yafuu B side of FIG. This piezoelectric buzzer 20 has a resin case 21 having a bottomed cylindrical shape with one end open, and a disk-shaped piezoelectric element 22 attached to the surface facing the inner side of the resin case 21.
A disk-shaped diaphragm 23 that is attached to cover the opening of 21
And an elastic metal terminal 24a electrically connected to the piezoelectric element 22 and an elastic metal terminal 25b electrically connected to the diaphragm 23. The resin case 21 has a bottom portion 21a and a side wall 21b, and a caulking fixing portion 25 is formed at an upper end portion of the side wall 21b in FIG. This crimp fixing part
The periphery of the diaphragm 23 is crimped and fixed by 25.
Further, a pair of terminal receiving grooves 26, 27 are formed on the side wall 21b of the resin case 21, and the terminal receiving grooves 26 and 2 are formed.
7 is arranged on one diameter line of the bottom portion 21a. The terminal receiving groove 26 and the diaphragm 23 constitute a sound emitting hole 28. Further, the sound output hole 29 is configured by the other terminal receiving groove 27 and the diaphragm 23.

The metal terminal 24a is bent at about 90 degrees and its free end is bent to the outside through the notch 26, and a bent portion 50a.
And an elastic portion 51a that is narrower than the bent portion 50a so as to obtain appropriate elasticity. The elastic portion 51a is in the resonance space 30 defined by the vibrating plate 23 and the resin case 21, and its tip elastically contacts the piezoelectric element 22. The other metal terminal 24b also has the same structure as the metal terminal 24a, and the corresponding portion is shown with a subscript b. The elastic portion 51b of the metal terminal 24b is in the resonance space 30 and its tip elastically contacts the diaphragm 23. These metal terminals 24a and 24b are caulked and fixed by caulking fixing portions 31a and 31b of the bottom portion 21a. The metal terminals 24a, 24b may be fixed by other fixing method instead of crimping.

In the piezoelectric buzzer 20 having such a configuration, the metal terminal 24
When a drive voltage is applied to the piezoelectric element 22 via a and 24b,
The vibrating plate 23 vibrates in a vibration mode such as a thickness longitudinal vibration mode, and sound waves are emitted in the resonance space 30, and the resonance space
In 30, it resonates at a constant resonance frequency, and this resonance sound is sent to the outside through the sound output holes 28 and 29, and thus the buzzer is activated.

The opening dimension l1 (see FIG. 3) of the terminal receiving grooves 26, 27 is selected to a value corresponding to a predetermined resonance frequency.

Next, an assembling operation of the piezoelectric buzzer 20 having such a configuration will be described. First, as shown in FIG. 4, the side wall 21b
A resin case 21 having an annular convex portion 35 formed on the upper end surface thereof is prepared. In this resin case 21, the terminal receiving groove 2
6,27 are formed. And then, the metal terminals 24a, 24b
Is attached to the bottom 21a. That is, the metal terminals 24a and 24b are partially bent in advance by 90 degrees, and the bent portions 50a and 50b
Insert b into the terminal receiving groove 26, 27, and bend 50a, 50b
The caulking fixing portions 31a, 31b are inserted into the mounting holes 32a, 32b (see FIG. 1) formed in the. After that, the caulking fixing parts 31a, 3
Heat and pressurize 1b and crimp. Thus the metal terminals 24a, 24
The b is fixed to the bottom portion 21a of the resin case 21. In this state, the tips of the elastic portions 51a, 51b of the metal terminals 24a, 24b extend toward the opening side of the resin case 21.

Then, in such a state, the piezoelectric element 22 faces the bottom portion 21a side, and the peripheral portion of the diaphragm 23 is stepped on the resin case 21.
Temporarily fix it to 60 (see Fig. 4). And the resin case 21
The convex portion 35 of is pressurized while being heated. By this, the convex part
35 is thermally deformed as shown in FIG. 1 to form a caulking fixing portion 25, which fixes the peripheral portion of the diaphragm 23. In this way, the piezoelectric buzzer 20 shown in FIG. 1 is assembled by the work from one direction.

In addition, the convex portion 35 is partially crimped so that the resin case 21 and the diaphragm 23
May be fixed, or the diaphragm 23 may be fixed to the resin case 21 with screws or the like. Further, the metal terminals 24a, 24 may be assembled by using the continuous hoop-shaped terminal 79 as shown in FIG. 5, which allows continuous production.

Although the caulking fixing portions 25, 31a, 31b are heat-sealed in the above embodiment, they may be processed by ultrasonic welding in a short time.

Further, in the above-described embodiment, the sound output holes 28, 29 are the terminal receiving grooves 26,
Although it is formed on the side wall 21b of the resin case 21 also as 27, the side wall 21b may be formed separately, or may be formed on the bottom portion 21a of the resin case 21.

Further, although the piezoelectric buzzer has been described in the above-described embodiments, the present invention can be suitably applied to a sounding body that emits sound by using other piezoelectric elements.

Effects of the Invention As described above, according to the present invention, the following effects are achieved.

No cover is required as in the prior art, so the number of parts can be reduced.

Since the contacts of the metal terminal and the diaphragm and the contacts of the metal terminal and the piezoelectric element are in the resonance space, it is not necessary to solder the contacts as in the prior art.

When assembling the piezoelectric sounder according to the present invention, the metal terminal may be inserted and fixed in the resin case, and the following diaphragm may be inserted and fixed. The piezoelectric sounder can be continuously assembled in one direction, and therefore continuous production is possible. It becomes possible to do it.

When the piezoelectric sounder according to the present invention is used by being mounted on a mounting board such as a printed circuit board that is wider than the piezoelectric sounder itself, the sound emission holes should be positioned in a direction perpendicular to the board surface and emit sound in a direction parallel to the board surface. However, a part of the sound wave emitted from the sound emission hole is reflected by the substrate surface and goes upward. Then, the reflected sound wave overlaps with the sound wave emitted directly upward from the diaphragm, and acts to increase the sound pressure above the substrate. Therefore, according to the present invention, it is possible to obtain the effect that the upward sound can be enhanced by mounting the piezoelectric sounder on the mounting substrate wider than the piezoelectric sounder itself.

[Brief description of drawings]

1 is a sectional view of a piezoelectric buzzer of an embodiment of a piezoelectric sounder according to the present invention, FIG. 2 is a plan view seen from the side A of FIG. 1, and FIG. 3 is a side view of FIG. A side view seen from the side, FIG. 4 is a perspective view of a resin case at the time of assembly, FIG. 5 is a plan view of a continuous hoop-like terminal 70 used when assembling the metal terminals 24a and 24b, and FIG. 6 is a typical view. FIG. 7 is a sectional view of another prior art, and FIG. 7 is a sectional view of another prior art. 20 …… Piezoelectric buzzer, 21 …… Resin case, 21a …… Resin case bottom, 21b …… Resin case side wall, 22 …… Piezoelectric element, 23 …… Vibrating plate, 24a, 24b …… Metal terminal, 26, 27 …… Terminal receiving groove, 30 …… Resonance space.

Claims (1)

[Claims] 1. A vibrating plate having a piezoelectric element attached to one surface thereof, and a resin case for fixing the vibrating plate, and a pair of metal terminals electrically connected to the piezoelectric element and the vibrating plate respectively. In the piezoelectric sounder configured to apply a driving voltage to the piezoelectric element, the resin case has a bottomed cylindrical shape with one end opened, and a pair of terminal receiving grooves is formed on a side wall of the resin case. Is attached to the resin case opening so as to close the opening of the resin case and forms a sound emitting hole between the terminal receiving groove and the metal terminal, and the metal terminal is fitted into the terminal receiving groove. And one end of which extends to the outside, the other end of which extends into the resonance space formed by the vibrating plate and the resin case, and elastically contacts the piezoelectric element and the vibrating plate, respectively. Being done Piezoelectric sounder and butterflies.