JPS6025102Y2 - sound generator - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sound generating device used in an alarm clock or the like.

An object of the present invention is to provide a sound generating device with good space efficiency and excellent magnetic efficiency.

An embodiment of the present invention will be described below based on the drawings.

As shown in Fig. 1, on the mounting plate 1 such as a printed circuit board (
The lower surface is the surface on which printed wiring is formed.

) is provided with a cap-shaped synthetic resin horn 2.

The horn 2 has a resonance chamber 2a and an acoustic escape hole 2b for producing a resonance effect.

A support base 3 made of a magnetic material is press-fitted into a recess 2c formed in the lower inner peripheral surface of the horn 2.

Note that an adhesive may also be used for this fixing.

The horn 2 has a plurality of mounting legs 2d at its lower end.
... are installed vertically, each leg of which is inserted into a hole pre-drilled in the mounting plate 1, and the lower end of each leg is welded to the lower surface of the mounting plate 1.

3 is a conductive member formed in a ring shape.

The support stand 3 has a plurality of fixed legs 3a at its lower part.
Each leg passes through a mounting hole pre-drilled in the mounting plate 1, and the lower end of the leg connects to a printed wiring (not shown) formed on the lower surface of the mounting plate 1.

) and are connected by solder 4.

Further, the peripheral edge of the diaphragm 5 is held between the upper surface 3b of the support base 3 and the upper end surface of the horn recess 2c.

The diaphragm 5 is made of a conductive material such as stainless steel, beryllum copper, or phosphor bronze.

On the lower surface of the diaphragm 5, for example, titanium barium (Ba
A piezoelectric element 6 such as Tt 03 ) is fixed, and driving electrode films 6a and 6b shown in the second figure are adhered to both sides of the piezoelectric element.A coil spring as a connecting member is attached to the lower surface of the piezoelectric element 6. The upper end of the coil spring 7 is connected to the mounting plate 1 by its spring force.
It passes through the through hole 1a and is connected and fixed to the printed wiring on the lower surface of the mounting plate via solder 9.

Therefore, the drive electrode film 6a of the piezoelectric element 6. 6b, for example, one of them 6a is connected to the diaphragm 5 and the support base 3,
The other end 6b is connected to the printed wiring on the lower surface of the mounting plate 1 via the coil spring 7, forming the circuit shown in FIG.

A booster coil 10 is wound around the core 8, and this core has protrusions 3c protruding inwardly from the upper part of the support base 3.
It is considered impossible to escape due to ..., and upward movement is restricted.

As shown in FIG. 2, the boost coil 10 is connected to the piezoelectric element 6 on one side and to the transistor 11 on the other side.

The transistor 11 is a reference mechanism (not shown).

) through the reference switch 12 that opens and closes the integrated circuit 13.
is connected to.

The transistor 11 is turned on and off by a signal from the integrated circuit 13, and when the transistor is off, a reverse induced voltage of the inductance is applied to the booster coil 10.

Next, the operation will be explained.

When the target set time arrives and the target switch 12 is turned on, a signal from the integrated circuit 13, for example 1024H2 (
The transistor 11 is turned on and off by a signal of 2048 Hz).

When the transistor 11 is off, a reverse induced voltage of the inductance is applied to the boost coil 10, and an electrostrictive phenomenon occurs in the piezoelectric element 6.

Therefore, the diaphragm 5 vibrates and generates a buzzer sound, which resonates with the hip horn 2 and provides a sufficient volume.

Also, since the coil spring 7 is brought into elastic contact with the piezoelectric element 6,
The resonant frequency band of the vibration system decreases.

Therefore, a low-pitched buzzer sound can be obtained without reducing the thickness of the diaphragm or piezoelectric element.

To explain how to assemble the sound generator according to the present invention, first, the core 8 placed on the mounting plate 1 is held down by the support base 3.

After the support base 3 is fixed on the mounting plate 1, the piezoelectric element 6 is fixed on the support base, and the diaphragm 5 is constructed.

Next, the horn 2 is press-fitted into the support base 3 from above, and the diaphragm 5 is clamped on the support base to complete the assembly.

Since the support base 3 is made of a magnetic material such as iron, a closed magnetic path is formed by the core 8, the collar integral with the core, and the support base 3, and magnetic efficiency is improved.

According to the present invention described above, the boosting coil is housed between the diaphragm and the mounting plate, which improves space efficiency; and because the coil spring is brought into elastic contact with the piezoelectric element, the resonant frequency of the diaphragm The band can be easily lowered, a low-pitched buzzer sound can be obtained, and manufacturing and assembly are simple.

Furthermore, since the support base and the core are made of magnetic material, the magnetic efficiency of the booster coil is good.

Furthermore, since the diaphragm, the support base, and the coil spring are made of conductive materials, the piezoelectric element can be electrically connected to the drive circuit without the need for soldering, and the structure is simple.

Furthermore, since a protrusion for pressing the core is provided at the end of the support base, excellent effects such as stabilization of the core storage state can be obtained.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, with FIG. 1 being a longitudinal sectional view and FIG. 2 being a circuit diagram. 1...Mounting plate, 1a...Through hole, 2...Curve/horn, 3...Support stand, 3c...Protrusion, 5...Opening Expansion plate, 6...Piezoelectric element, 7.
...Coil spring, 8a, curved, center hole, 8...
・・Core, 10・Bend・Boost coil.

Claims (3)

[Scope of utility model registration request] (1) A mounting plate, a horn placed on the mounting plate, a support made of magnetic material provided inside the horn, a diaphragm installed and supported on this support, and a piezoelectric element fixed to this diaphragm. a further core of magnetic material disposed in the gap between the diaphragm and the mounting plate; a step-up coil wound around this core and connected to the piezoelectric element; and a center provided in the center of the core. a hole, a through hole provided in the mounting plate opposite to the center hole, and a coil spring inserted through the through hole and the center hole and in elastic contact with the piezoelectric element, and serves as a support for the magnetic material. A sound generating device characterized in that the magnetic path of the booster coil is formed in a closed loop in cooperation with the core of the magnetic material. (2) Utility Model Registration Scope of Claims In paragraph 1, the diaphragm, the support stand, and the coil spring are formed of conductive materials.One drive electrode membrane of the waist piezoelectric element is connected to the drive circuit via the diaphragm and the support stand. and the other drive electrode film is connected to a drive circuit via a coil spring. (3) The sound generating device according to claim 1 or 2 of the utility model registration claim, wherein the support has a protrusion on a part thereof to restrict movement of the core.