JPS60260298A - Piezoelectric electroacoustic transducer - Google Patents

Abstract

PURPOSE:To simplify the assembling and to reduce the number of components by pressing a load of the vibrator and an input/output terminal fixed to a back air chamber board while using a convexed part of the front air chamber board and the concaved part of the back air chamber for fitting. CONSTITUTION:A notch 28 is provided to a part of the diaphragm 27 at a position to which a projection 24 from the front air chamber board 21 is inserted. A lead 29 is soldered to one electrode of a ceramic piezoelectric body 26 and positioned to pass the apex of the projection 24 of the chamber board 21 at assembling. The back air chamber board 30 has a step 31 at the peripheral and the concaved part 32 is formed to a part of the step 31. Further, terminals 33, 34 are fixed to the chamber board 30, a part of the terminal 33 reaches the concaved part along the air inner face of the chamber board 30 and connected electrically with the lead 29. The connection is executed by the pressing by means of fitting between the projection 24 of the board 21 and the concaved part 32 of the board 30.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to an electroacoustic transducer used in handsets such as telephones and intercoms, and in particular relates to a piezoelectric electroacoustic transducer using a piezoelectric material as a transducer. Ah.

Conventional configurations and their problems Piezoelectric electroacoustic transducers often use vibrators in which a ceramic piezoelectric body is attached to a metal diaphragm. When designing various electroacoustic transducers using this vibrator, important issues include how to support and fix the vibrator and how to connect input and output lead wires.

FIG. 1 shows a conventional example. 1 is a ceramic piezoelectric material with silver baked on both sides. Reference numeral 2 denotes a metal diaphragm which is closely bonded to the ceramic piezoelectric body 1 with an adhesive, and the two form a vibrator. They are also electrically connected at the same time.

3 is a case, which is integrated with a back air chamber plate having acoustic leak holes 7 and input/output terminals 10.15. A ring 4 secures a space between the diaphragm 2 and the front air chamber plate 5 having the sound emitting holes 6, and fixes the diaphragm 2 around the periphery. 8 is a ceramic piezoelectric body 10
11 is a soldering part for connecting the lead wire 9 to the input/output terminal 10, and 12 is a soldering part for electrically separating the case 3 and the input/output terminal 1o. It is an insulator ・13 is the lead wire 14 to the diaphragm 2
The soldered part 15 to which the terminal is connected is the other input/output terminal, and the lead wire 14 is connected at the soldered part 16.

Such a conventional structure has a large number of parts, is complicated to assemble, and has poor workability.

OBJECTS OF THE INVENTION The present invention overcomes the above-mentioned drawbacks of the prior art and provides a piezoelectric electroacoustic transducer that is easy to assemble and has a small number of parts.

Structure of the Invention In order to achieve this object, the piezoelectric electroacoustic transducer of the present invention has a conversion structure with three degrees of freedom consisting of a front air chamber, a vibrator, and a back air chamber, and the human output to the vibrator is 1ii%'! between the electrical connection means of the nodame and the above-mentioned vibrator! &Jf4f,
6*a6o! @! &KEiffiffJ.

The input/output terminals used are those that are pressure-contacted.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 to 6. In the figure, 21 is a front air chamber plate, which has a plurality of sound emitting holes 2.
2, and a step 23 is provided at the periphery.

A convex portion 24 is provided in a part of this step 23. 2
A oscillator 5 forms a front air chamber with the front air chamber plate 21, and is constructed by bonding a ceramic piezoelectric body 26 and a metal diaphragm 27 together. A part of the diaphragm 27 has a notch 2 at a position where the protrusion 24 from the front air chamber plate is inserted.
8 is provided. Further, the ceramic piezoelectric body 26
A lead wire 29 is soldered to one electrode of the chamber plate 21, and the lead wire 29 is positioned so as to pass through the apex of the convex portion 24 of the chamber plate 21 during assembly. 3o is the back chamber plate,
It has a step 31 around the periphery, and a recess 32 is formed in a part of the step 31. Further, terminals 33 and 34 are fixed to the back air chamber plate 30, and a part of the terminal 33 reaches the recess 32 at 3° of the back air chamber plate along the inner surface of the back air chamber plate 30. It is electrically connected to the lead wire 29.

This electrical connection is made by fitting the protrusion 24 of the front air chamber plate 21 and the recess 32 of the back air chamber plate 30 into pressure contact. Also, a part of the terminal 34 reaches the step 31 of the back air chamber plate 3o along the inner surface of the back air chamber plate 30, is bent, and is bent at the bottom of the recess 35 provided in a part of the step 31. A portion of the diaphragm 27 is sandwiched between the distal end portion 36 of the positioned terminal 34 and the stepped portion 23 of the front air chamber plate 21 to establish an electrical connection. This electrical connection can also be made by methods such as welding or soldering.

Further, when a portion of the terminals 33, 34 runs along the inner surface of the back air chamber plate 30, the tip portions 39, 36 of the terminals 33, 34 are formed by protrusions 37, 38 provided at a portion in the middle thereof. Reliable electrical contact is also ensured by being strongly pressed against the end of the lead wire 29 and the end of the diaphragm 27, respectively. Further, the back air chamber plate 30 is provided with small diameter holes 40, 40a to flatten the sound pressure-frequency characteristics. Reference numeral 41 denotes a metal ring for holding and fixing the outer circumferences of the front air chamber plate 21 and the back air chamber plate 3o, and securely fixes the periphery of the vibrator 25.

FIG. 6 shows another embodiment, and the only difference from the embodiment shown above is that the terminals 42 and 43 have the same shape. Furthermore, the convex portions 45 and 46 of the front air chamber plate 44 have a symmetrical shape, and the concave portions 48 and 49 of the back air chamber plate 47 that fit therewith also have a symmetrical shape.

The electrical connection between the terminal 43 and the diaphragm 50 is achieved by providing a cut-and-raised portion 51 in a portion of the diaphragm 50 corresponding to the convex portion 46 of the front air chamber plate 44 and molding it into a key shape. The connection is made in exactly the same way as the connection between the terminal 42 and the lead wire 52 as described in the example.

The lead wires mentioned in these examples should be thin so as not to adversely affect the deflection vibration of the sensor, but from the viewpoint of strength, thin wires should be bundled and both ends stiffened with short sleeves, or foil-like. things are suitable.

Further, the front air chamber plate and the back air chamber plate may be either thermoplastic or thermosetting as long as they are insulators, depending on the purpose of use. Further, as long as the diaphragm is an electrical conductor and can be made thin, it can be appropriately selected depending on the type of reliability required. Brass plates, iron-nickel alloy plates, etc. are usually used. In order to ensure reliability at the contact portion, the terminal is made of a brass plate plated with copper, soot, lead, or the like, but it may also be plated with gold, silver, platinum, or the like.

The metal ring on the outer periphery is made of aluminum, brass, iron, etc. in order to securely hold the front air chamber plate and back air chamber plate. You can also tighten it.

Effects of the Invention As described above, according to the present invention, as shown in the embodiments, the structure is simplified compared to the conventional structure, the number of parts is reduced, and therefore assembly is easy, and the invention has engineering significance. An electroacoustic transducer can be realized.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional electroacoustic transducer, and Fig. 2 is an implementation diagram of a piezoelectric electroacoustic transducer according to the present invention.
．． □3 * tri @□2. . 4-□・ Figure 4 is a cross-sectional view taken along line BB' in Figure 2, Figure 5 is an exploded perspective view, Figure 6 shows another embodiment of the present invention. FIG. 21.44...Front air chamber plate, 23...Step, 24°45.46...Protrusion, 25...
・Vibrator, 26...Ceramic piezoelectric body, 27.60
...Metal diaphragm, 28...Notch, 29
．． 52... Electrical connection means (lead wire), 30.
...Back air chamber plate, 31...Step, 32.4
8.49... Concavity, 33, 34, 42°43...
- Input/output terminal, 51... cut and raised part. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2〆 63 Figure 2 Figure 3

Claims (1)

[Scope of Claims] (1) It has a conversion structure with three degrees of freedom consisting of a front air chamber, a vibrator, and a back air chamber, and includes electrical connection means for input and output to the vibrator, and A piezoelectric electroacoustic transducer characterized in that the input/output terminals fixed to the back air chamber plate for forming the back air chamber are in pressure contact between the transducers. (2) A vibrator is constructed by bonding a ceramic piezoelectric body to a metal diaphragm having a notch in a part of its periphery, and a lead wire from the ceramic piezoelectric body is arranged in the notch part of the diaphragm. 2. A piezoelectric electroacoustic transducer according to claim 1, further comprising electrical connection means for input and output terminals comprising lead wires and a diaphragm. (3) A step is provided around the front air chamber plate to form a front air chamber between the vibrator, a convex part is provided on a part of the step, and a step is provided around the back air chamber plate. At the same time, a recess is provided in a part of the step, and a part of the input/output terminal is arranged at the bottom of the recess, and the convex part of the front air chamber plate is connected to the notch of the diaphragm and the recess of the back air chamber plate. The leads from the ceramic piezoelectric body are pressed into contact with the convex part of the front air chamber plate and a part of the terminal at the bottom of the recess of the back air chamber plate, and at the same time, the periphery of the vibration plate 5 is connected to the front air chamber. 3. The piezoelectric electroacoustic transducer according to claim 2, wherein the piezoelectric electroacoustic transducer is fixed by a step between the plate and the back air chamber plate. (4) A cut-and-raised part is provided in a part of the diaphragm, and the cut-and-raised part is pressed into contact with the convex part of the front air chamber plate and a part of the terminal at the bottom of the recess of the back air chamber plate. A piezoelectric electroacoustic transducer according to claim 2. (6) The piezoelectric electroacoustic transducer according to claim 2, further comprising means for lifting a part of the terminal provided at the bottom of the recess of the back air chamber plate from the bottom of the recess.