JPS5825676Y2 - Piezoelectric electroacoustic transducer - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a piezoelectric electroacoustic transducer using a piezoelectric bimorph, and aims to provide a highly reliable piezoelectric transducer with stable characteristics.

A conventional piezoelectric electroacoustic transducer was constructed as shown in FIG.

In other words, case 1 has an open top and a through hole in the center of the bottom.
A disk-shaped piezoelectric bimorph 3 whose periphery is held by an elastic support 2 is disposed inside the piezoelectric bimorph 3. A vibration transmission pipe 4 is connected to the center of the upper surface of the piezoelectric bimorph 3. The central portion of a conical diaphragm 5 whose peripheral edge is connected to the peripheral edge of the case 1 is connected.

With this configuration, when an alternating current is applied to the piezoelectric bimorph 3 via the lead wire 6, it vibrates with a node at 60% of the radius at the first resonance frequency, as shown in FIG.

Therefore, the vibration transmission pipe 4 fixed to the center of the piezoelectric bimorph 3 vibrates as a piston and drives the center of the diaphragm 5 to generate sound.

According to such a configuration, the piezoelectric bimorph 3, the vibration transmission pipe 4, and the diaphragm 5 are bonded at points, so the bonding area is small, the bonding force is weak, the structure is relatively complex, and the performance varies widely. Since the diaphragm 5 is driven point-driven at the center, there are large variations in performance depending on the bonding state, resulting in poor reliability.

The present invention eliminates the above-mentioned drawbacks of the prior art.

Hereinafter, an embodiment of the present invention will be explained with reference to FIG. 3 of the drawing.

7 is made of synthetic resin, etc. with an open top and a through hole 8 in the center of the bottom.
This case 7 has an elastic support 9 inside.
is arranged, and a disk-shaped piezoelectric bimorph 10 is attached to this elastic support body 9.

The joint between the elastic support 9 and the piezoelectric bimorph 10 is located at 60% of the node radius of the piezoelectric bimorph 10.

A dome-shaped diaphragm 11 is adhesively bonded to the outer periphery of the piezoelectric bimorph 10, and an edge portion 12 of the diaphragm 11 is adhered to the upper end surface of the case 7 with a mounting ring 13.

When an alternating current is applied to the lead wire 14 of the piezoelectric bimorph 10 with such a configuration, the piezoelectric bimorph 10 vibrates with nodes at 60% of the radius at the first resonance frequency.

Therefore, the diaphragm 11 coupled to the outer circumference of the piezoelectric bimorph 10 is driven, and the diaphragm 11 generates a sound corresponding to the vibration.

Although such an operation is performed, since the diaphragm 11 is directly coupled to the piezoelectric bimorph 10, the vibration of the piezoelectric bimorph 10 is transmitted to the diaphragm 11 with almost no loss, and faithful reproduction can be performed.

However, since the diaphragm 11 is surface-bonded to the piezoelectric bimorph 10, the bonding strength is high and the performance is extremely stable.

Since the piezoelectric electroacoustic transducer of the present invention is constructed as described above, the coupling between the piezoelectric bimorph and the diaphragm is strong.
In addition to stabilizing the performance, the structure is simpler as a vibration transmission pipe is no longer required, making assembly easier and improving productivity.Since the diaphragm is driven over a wide area, there is less variation due to adhesion. It is highly reliable and has great practical value.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing a conventional piezoelectric electroacoustic transducer, Figure 2 is an explanatory diagram showing the vibration form of the piezoelectric bimorph, and Figure 3 is a cross-sectional view showing a conventional piezoelectric electroacoustic transducer.
The figure is a sectional view showing an embodiment of the piezoelectric electroacoustic transducer of the present invention. 7... Case, 9... Elastic support, 1
0... Piezoelectric bimorph, 11... Vibration plate.

Claims (1)

[Scope of utility model registration request] In a piezoelectric electroacoustic transducer in which a diaphragm is coupled to a piezoelectric bimorph that vibrates as a node at 60% of the radius by applying alternating current, the nodes of the piezoelectric bimorph are supported, and the outer peripheral surface of the piezoelectric bimorph is A piezoelectric electroacoustic transducer made by combining dome-shaped diaphragms.