JPH051199Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a piezoelectric acoustic transducer used in telephone handsets and the like.

<Prior art> Generally, this type of piezoelectric acoustic transducer for telephones is
It is necessary to provide a three-degree-of-freedom vibration system in which air chambers are provided on both sides of the piezoelectric vibrator, and connector-type terminals are often used due to the necessity of maintenance and replacement.

An example of such a type of device is known, as shown in the longitudinal sectional view of FIG. 8, for example. In the figure, reference numeral 4 denotes a piezoelectric vibrator, which has a unimorph structure in which a small-diameter ceramic piezoelectric element 6 is bonded to a large-diameter metal diaphragm 5. be accommodated in. A step 3 is formed in the case 1, and the piezoelectric vibrator 4 is supported by the step 3 and positioned and held with air chambers 8 and 22 provided on both sides thereof. A ring-shaped insulating insert member 9 is inserted into the case 1, and an insulating cover 11 that closes the opening of the case 1 is attached to the insulating insert member 9. The end portion is caulked and fixed to the outer surface of the insulating cover 11. As a result, the piezoelectric vibrator 4 is connected to the case 1 at its outer periphery.
and the insulating insertion member 9.

The insulating cover 11 has a pair of external terminals 18,
19 is inserted and fixed in the case 1,
An insulated lead wire 33 soldered to the diaphragm 5 of the piezoelectric vibrator 4 is soldered to one terminal, and the other lead wire 32 soldered to the electrode surface 7 of the piezoelectric element 6 is soldered to the other terminal. is connected by solder. Furthermore, the insulating cover 11 has a brake hole 2.
0 is formed, and this brake hole 20 is connected to the case 1.
The damping film 21 covers the insulating cover 1 from the inside.
It is glued to 1.

In the conventional piezoelectric acoustic transducer configured as described above, when an audio signal is applied to the external terminals 18 and 19, the piezoelectric vibrator 4 bends and vibrates, and sound is generated from the sound emission hole 2 of the case 1. , the handset is configured.
Conversely, when sound is applied to the piezoelectric vibrator 4 through the sound emitting hole 2, the piezoelectric vibrator 4 bends and vibrates, and the external terminal 1
At 8 and 19, electrical signals are extracted and a transmitter is constructed.

<Problems to be solved by the invention> However, when assembling the piezoelectric acoustic transducer described above, the internal wiring must be connected by soldering, and in addition, the external terminals 18 and 19 must be connected to improve reliability. Since the lead wires 32 and 33 have to be wound around the wires, it is not only difficult to work, but also causes high costs.

In view of these conventional problems, it is an object of the present invention to provide a piezoelectric acoustic transducer that does not require insulated lead wires and is easy to assemble.

<Means for solving the problem> In order to achieve this purpose, this invention
The insulating cover is constituted by a printed wiring board, and the conductive pattern of the insulating cover is electrically connected to the electrode surface of the piezoelectric element via a spring terminal, and
The spring terminal is integrally constituted by a flat mounting base and a plurality of spring parts rising from the mounting base in an inclined manner via rising parts rising substantially perpendicularly to the mounting base. It is characterized by a structure in which solder connection is made on the conductive pattern.

<Example> Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 is a central vertical sectional view of this embodiment, and FIG. 2 is an exploded perspective view thereof. In these figures, reference numeral 1 denotes a circular case made of metal, and this case 1 is formed into a cap shape with one end open, and has a sound emitting hole 2 formed in the center and a ring-shaped case inside. A step portion 3 is formed, and a piezoelectric vibrator 4 is housed and arranged on this step portion 3. This piezoelectric vibrator 4 is composed of a unimorph vibrator in which a ceramic piezoelectric element 6 made of a disk with a diameter smaller than that of the diaphragm 5 is bonded to a thin disk-shaped metal diaphragm 5, and the electrode surface of this piezoelectric element 6 is 7 is the case 1
The metal diaphragm 5 is disposed so that its outer peripheral portion is in contact with the stepped portion 3 while facing toward the opening side of the metal diaphragm 5 . This stepped portion 3 creates a first space between the piezoelectric vibrator 4 and the case 1 in the case 1 on the sound emission hole 2 side.
The air chamber is configured.

A ring-shaped metal insertion member 40 is fitted onto the side surface of the case opening of the metal diaphragm 5 . A disc-shaped insulating cover 11 is inserted and fixed onto the side surface of the case opening of the insertion member 40. This insulating cover 11 is composed of a printed wiring board. That is, on the upper surface of the insulating cover 11, there is a ring-shaped electrode 12 along the outer periphery of the insulating cover 11, one extraction electrode 13 drawn inward from a part of the ring-shaped electrode 12, and a ring-shaped electrode 12. A conductive pattern 15 made of copper foil is formed with the other lead electrode 14 formed at a position apart from the conductive pattern 15 . Through holes 16 and 17 are bored in the terminal portions of both extraction electrodes 13 and 14 in the thickness direction of the insulating cover 11, and external terminals 1 are formed in each through hole 16 and 17, respectively.
8 and 19 are mounted and fixed in a state where they are electrically connected to each extraction electrode. Further, a brake hole 20 is formed in the insulating cover 11, and a brake film 21 is bonded to the insulating cover 11 so as to cover the brake hole 20 from the inside of the case 1.

The open end of the case 1 fitted with the insulating cover 11 is caulked and fixed to the outer surface of the insulating cover 11, so that the outer periphery of the piezoelectric vibrator 4 is connected to the stepped part 3 and the intervening part. The second air chamber 22 is clamped and fixed between the piezoelectric element 6 and the insulating cover 11 by the insertion member 40 . Furthermore, the insertion member 40
The metal diaphragm 5 and the ring-shaped electrode 12 of the insulating cover 11 are electrically connected due to the conductivity.

FIG. 3 is an enlarged exploded perspective view of the main parts showing the other extraction electrode 14 and the spring terminal 23A connected thereto, and FIG. 4 is a side view thereof, and the spring terminal 23A in these figures is flat. It consists of a mounting base 24 and a pair of spring parts 25, 25 which also rise in an inclined manner from both sides of the mounting base 24, and between the mounting base 24 and each spring part 25 there is a A rising portion 27 is formed that stands up substantially vertically. The mounting base 24 is connected to the other lead electrode 14 by soldering. As a method of this soldering, for example, a solder paste 26 is applied onto the other extraction electrode 14, and the solder paste 26 is
After placing the spring terminal 23A on the flat mounting base 24, apply a soldering iron to the flat mounting base 24 and connect both 1
This is done by fixing between 4 and 24. In this attached state, the free end contact portions of the spring portions 25, 25 of the spring terminal 23A are in pressure contact with the electrode surface 7 of the piezoelectric element 6, thereby connecting the piezoelectric vibrator 4 and one external terminal 18. are electrically connected via the spring terminal 23A and the other extraction electrode 14. On the other hand, the piezoelectric vibrator 4 and the other external terminal 19 are electrically connected via the metal diaphragm 5, the insertion member 40, the ring-shaped electrode 12, and the one extraction electrode 13.

According to this embodiment, when connecting the piezoelectric vibrator 4 and the external terminal 18, the insulating cover 1
Spring terminal 23A on the conductive pattern 15 of 1
Since it is only necessary to solder the wires, complicated wiring and connection work for lead wires is no longer necessary.

Incidentally, the reason why the raised portion 27 is formed between the mounting base 24 and each spring portion 25 that constitute the spring terminal 23A is that by providing this raised portion 27, the spring portions 25, 25 which are caused by solder bridging can be prevented. This is to prevent the spring pressure from changing. That is, such rising parts 27, 27
If , as shown by the imaginary line in Figure 4,
The protruding solder paste 26a reaches the bent portions of both spring portions 25, 25 formed by bending diagonally upward from both sides of the mounting base 24, changing the spring pressure value of the spring portions 25, 25, and eventually , which may also affect the vibration characteristics of the piezoelectric vibrator 4.
7, 27, the protruding solder paste 26a is blocked by the rising parts 27, 27 and does not reach the spring parts 25, 25, which impedes the desired vibration characteristics of the piezoelectric vibrator 4. This means that they will not be able to do so.

However, even in this embodiment, the following problems may still occur. That is, as shown in FIG. 5, since each of the spring parts 25, 25 is composed of one inclined plane, when it is incorporated into the thin second air chamber 22, the middle part thereof is curved. Then, the curved portions 28, 28 come into contact with the electrode surface 7 of the piezoelectric element 6, and the contact pressure of the spring portions 25, 25 as a whole becomes too large, changing the sound pressure frequency characteristics.

Therefore, the spring terminal 2 which is the first modification example
3B, as shown in FIG. 6, the intermediate portions of the spring portions 25, 25 of the spring terminal 23 are arranged so that the portions 25a, 25a on the free end side have a larger inclination gradient than the portions 25b, 25b on the proximal end side. It is bent so that it looks like this. In this way,
The spring terminal 23 is prevented from curving into a convex shape by the bent portions 29, 29, and both free end contact portions are correctly pressed against the electrode surface 7 of the piezoelectric element 6.

Furthermore, FIG. 7 is an enlarged cross-sectional view of a main part showing a second modification of the spring terminal. In this spring terminal 23C, a fitting protrusion 30 is formed protrudingly on the back side of the mounting base 24, and the insulating cover 11
A through hole 31 into which the fitting protrusion 30 is positioned and fitted.
has been formed. In this way, the spring terminal 23C, which has a small shape, can be easily positioned on the insulating cover 11.

<Effects of the invention> As described above, according to the invention, the insulating cover is constituted by a printed wiring board, the conductive pattern of this is electrically connected to the electrode surface of the piezoelectric element via a spring terminal, and The spring terminal is composed of a flat mounting base and a plurality of spring parts that stand up in an inclined manner from the mounting base via a rising part that stands up almost perpendicularly to the mounting base, and the mounting base is connected to the conductive pattern. Since it is soldered to the top, the conventional insulated lead wire is not required. Therefore, the assembly work can be easily performed.

[Brief explanation of drawings]

Figures 1 to 7 show a piezoelectric acoustic transducer according to this embodiment, with Figure 1 being a central vertical sectional view of this embodiment, Figure 2 being an exploded perspective view thereof, and Figure 3 being a main part. Figure 4 is an enlarged cross-sectional view, Figure 4 is its side view, Figure 5 is
The figure is a sectional view showing a defective assembled state of the spring terminal, FIG. 6 is a side view showing a first modification of the spring terminal, and FIG. 7 is a main part showing a second modification of the spring terminal. It is an enlarged sectional view. Also,
FIG. 8 is a longitudinal sectional view showing a piezoelectric acoustic transducer according to a conventional example. DESCRIPTION OF SYMBOLS 1... Case, 3... Step part of case, 4... Piezoelectric vibrator, 5... Metal diaphragm, 6... Piezoelectric element,
7... Electrode surface of piezoelectric element, 8, 22... Air chamber,
40... insertion member, 11... insulation cover, 15...
...Conductive pattern, 23A-23C...Spring terminal, 24...Mounting base, 25...Spring part, 27...Rising part, 29...Middle part (bending part), 25a...Free end side part, 25b... ...Proximal end portion, 30... Fitting protrusion, 31... Through hole.

Claims (1)

[Claims for Utility Model Registration] (1) A piezoelectric vibrator is constructed by overlapping a metal diaphragm and a piezoelectric element formed with a smaller diameter than the metal diaphragm, and the piezoelectric vibrator is arranged so that the electrode surface of the piezoelectric element is disposed on a step formed in the metal case in a state facing the opening side of the case, and inserting a ring-shaped insertion member into the case, and
closing the opening of the case with an insulating cover;
A piezoelectric acoustic transducer comprising: an outer circumferential portion of the piezoelectric vibrator is clamped and fixed between the stepped portion and the insertion member, and air chambers are formed on both sides of the piezoelectric vibrator, wherein the insulating cover is printed. The conductive pattern is electrically connected to the electrode surface of the piezoelectric element via a spring terminal, and the spring terminal is connected to a flat mounting base and approximately perpendicular to the mounting base. It is integrally constructed with a plurality of spring parts rising in an inclined manner from the mounting base via a rising part,
A piezoelectric acoustic transducer characterized in that the mounting base is soldered onto the conductive pattern. (2) The intermediate portion of each of the spring portions constituting the spring terminal is bent such that the portion on the free end side thereof has a larger inclination gradient than the portion on the proximal end side. The piezoelectric acoustic transducer according to item 1. (3) The mounting base of the spring terminal is formed with a fitting protrusion protruding from the back side thereof, and the insulating cover is formed with a through hole into which the fitting protrusion is positioned and fitted. A piezoelectric acoustic transducer according to claim 1 or 2 of the patent registration claim.