JPS596071Y2 - Piezoelectric buzzer - sounding body - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a piezoelectric buzzer sounding body in which a piezoelectric vibrator, which is formed by pasting a piezoelectric ceramic element plate onto a metal diaphragm, is supported in a case having acoustic effects.

Piezoelectric buzzers are small, thin, lightweight, have low power consumption, have a long lifespan, and can generate various tones when combined with circuits.They are used as an alternative to conventional electromagnetic buzzers in various fields such as alarm notifications, etc. used in

However, as the applications have expanded, there has been a growing demand for better tones, that is, for lower frequencies.

Conventionally, for sounding bodies using two-terminal vibrators, in order to satisfy the demand for lower frequencies and to simplify the supporting method, a method of fixedly supporting the outer periphery of the diaphragm has often been adopted.

However, since a sounding body using a three-terminal type vibrator (hereinafter abbreviated as a three-terminal type sounding body) has a feedback electrode, a self-excited oscillation system can be adopted as the drive circuit system, resulting in a simple circuit system. Although it has the advantage of making it possible to significantly reduce the cost of the circuit section, the method of supporting the outer periphery of the diaphragm did not stabilize oscillation when connected to a self-excited oscillation circuit, making it practically impossible. .

A possible reason why this stable oscillation cannot be obtained is that the amount of feedback signal is insufficient.

In a self-excited oscillation circuit, the drive transistor must be sufficiently
It is necessary that the feedback signal is large enough to turn off the N and OFF signals, and this is related to the resonant impedance of the three-terminal sounding body.

That is, when the diaphragm's outer peripheral edge is fixedly supported, the resonance impedance of the sounding body becomes extremely large compared to when the free vibration nodes are supported.

As a result, the amplitude becomes small for the same input voltage, the feedback signal becomes extremely small, and the three-terminal sounding body that supports the nodes of free vibration stably oscillates, and the three-terminal sounding body that supports the outer periphery is difficult to oscillate.

Therefore, in order to solve such problems, methods have been considered to obtain stable oscillation by devising a method for attaching the sounding body to the object to be attached.

That is, this is a method in which a buffer is provided between the sounding body case body and the fixing part so that the vibrator and the body case can vibrate as one, as shown in FIG. 4.

In this method, the resonant impedance of the three-terminal outer periphery supported sounding element becomes the same value as when supporting nodes of free vibration, making self-oscillation possible, and making it possible to significantly reduce the cost of the circuit section. It takes time to tighten and fix the lead wires and to solder the lead wires, and in some cases, there is a concern that oscillation may be hindered due to the way the lead wires are pulled.

In order to solve these problems, the present invention aims to devise a method of mounting the sounding body, simplify the mounting, and eliminate quality problems caused by the mounting.

This will be explained below based on the drawings.

Figure 1 shows a 2-terminal type vibrator, Figure 2 shows a 3-terminal type vibrator, and Figure 3 shows a sounding body with two terminals supported on the outer periphery (fixed directly to the case). be.

Further, FIG. 4 shows a case body vibrating type sounding body having a thin connecting plate.

In addition, to explain each symbol, 1 is a two-terminal type vibrator, 2 is a diaphragm, 3 is a piezoelectric element, 4 is an element main electrode, 5 is a three-terminal type vibrator, 6 is a feedback electrode, and 7 is a sounding body case body. , 8.8' is a lead wire, 9 is a mounting part between the case body and the outer peripheral edge of the vibrator, 10 is a lead wire, 11 is a thin connecting plate, 1
2 indicates a flange.

FIG. 5 shows an embodiment of the present invention.

13. 13', 13'' are curved portions 15 (
(not shown), 15', 15" and a pin terminal made of conductive metal with an insertion tip 16. 16', 16" into the printed circuit board, 14. This is a lead wire that electrically connects the

Attach such a sounding body to the tip of the bottle 16 on a printed circuit board.
16', 16" are fixed by soldering, and input is applied through the pin terminal. Since the curved portions 15' and 15" of the pin have spring properties, a certain piece of resin is connected to the vibrator. The main body 7 is integrated and can vibrate.

Therefore, the impedance of the sounding body with the pin terminal fixed is not much different from that of the case where the free vibration node is supported, and a low value can be obtained, so a sufficient feedback signal can be obtained, and stable self-oscillation can be performed.

Of course, in FIG. 5, the pin terminal 13 and the lead wire 14 may be integrated, and the terminal is not limited to the pin terminal.
Even if the tip is fixed to a printed circuit board or the like, it may be conductive as long as it has a springy part between it and the case body.

As explained above, the present invention provides a sounding body case that fixedly supports the outer peripheral edge of a three-terminal type vibrator, and a conductive terminal having a springy part between the mounting tip and the case body. Since it serves both as support and power supply, it is possible to oscillate in a self-excited oscillation circuit, which allows for a significant cost reduction in the circuit section, and also makes it easy to attach to a board, etc., and there are no quality problems caused by attachment. It will be resolved.

[Brief explanation of the drawing]

Figure 1 shows a 2-terminal type vibrator, Figure 2 shows a 3-terminal type vibrator, and Figure 3 shows a 2-terminal type sounding body supported by the outer periphery (fixed directly to the case).
FIG. 4 is an explanatory diagram of a case body vibrating sounding body having a thin connecting plate, and FIG. 5 is an explanatory diagram of an embodiment of the present invention. is a side view, and the mouth is a bottom view. DESCRIPTION OF SYMBOLS 1...Two-terminal vibrator, 2...Vibration plate, 3...Piezoelectric element, 4...Element main electrode, 5...・3-terminal vibrator, 6...feedback electrode, 7...sounding body case, 8,8
'...Lead wire, 9...Mounting part, 10
...Lead wire, 11...Thin connecting plate,
12...Flange, 13.13', 13"...
...pin terminal, 14. 14', 14''...
-Lead wire, 15, 15', 15''...Bending portion with spring properties, 16.16', 16''...Insertion tip.

Claims (2)

[Scope of utility model registration request] 1. In a sounding body in which the outer periphery of a three-terminal vibrator bonded together with a piezoelectric element plate having a feedback electrode is supported and fixed to the inner circumferential surface of a case body that has acoustic effects, etc., there is a method for attaching and fixing the vibrator to an attached body. When three conductive terminals are provided vertically on the vibrator as leads for power supply to the vibrator, and the sounding body is attached to the object to be mounted, the sounding body case body becomes integrated with the vibrator and can vibrate in the vertical direction. A piezoelectric buzzer sounding body characterized in that the conductive terminal has sufficient springiness. 2. A piezoelectric buzzer sounding body according to claim 1, wherein the conductive terminal is a spring metal terminal curved in a substantially U-shape in a direction parallel to the diaphragm.