JP2000110796A - Piezoelectric bimorph fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric bimorph fan aimed at reducing weight and noise as well as improved air blowing efficiency by eliminating oscillation propagation loss. SOLUTION: A bimorph elastic portion and an oscillating section are integrated into a single piece by an anisotropic carbon fiber composite material 11, piezoelectric ceramics 2a and 2b are adhered to the upper and the lower surfaces of the composite material 11 and one end each of these elements is fixed by a fixture 3. Sine wave voltage with resonance frequency of a bimorph element is applied from an AC voltage supply 5 to the composite material 11. When this device is constructed such that the lower piezoelectric ceramics 2b may contract when the upper piezoelectric ceramics 2a expands, the antisotropic carbon fiber composite material 11 flexes in an oscillating manner with its end oscillating like a fan. Thereby a piezoelectric bimorph fan with high air blowing efficiency and no oscillation propagation loss is obtained. Moreover, the anisotropic carbon fiber composite material 11 causes no noise problem due to its light weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric bimorph fan utilizing bending vibration of a piezoelectric material such as piezoelectric ceramics.

[0002]

2. Description of the Related Art A conventional piezoelectric bimorph fan has a structure as shown in FIG. In FIG. 2, reference numeral 1 denotes a metal plate which is an elastic plate of a bimorph element, and piezoelectric ceramics 2a and 2b called PZT are provided on upper and lower surfaces of the metal plate 1.
Is glued. One end of the bimorph element is fixed by a fixing jig 3, and a vibrating plate 4 such as a plastic film is joined to the other end as shown in FIG.

The metal plate 1 is configured so that a sine wave voltage having a resonance frequency of a bimorph element is applied from an AC voltage source 5. If the lower piezoelectric ceramics 2b is configured to contract when the upper piezoelectric ceramics 2a expands, the metal plate 1 performs bending vibration in accordance with the polarity of the voltage, and the tip portion performs fan-shaped vibration. As a result, the amplitude of the distal end portion is greatly increased by the resonance of the diaphragm 4, and the diaphragm 4 is driven as a fan.

[0004]

A conventional piezoelectric bimorph fan has a diaphragm joined to the tip of a bimorph element. That is, a plastic film (diaphragm 4) is attached to the tip of the metal plate 1 of the bimorph element. Since the elastic modulus of the metal plate and the plastic film is largely different, loss of vibration propagation from the bimorph portion to the plastic film portion is lost. This causes a drawback that the blowing efficiency is deteriorated.

For example, when the bimorph elastic plate, that is, the metal plate 1 and the diaphragm 4 of the fan portion are integrally formed of a metal such as phosphor bronze, the above problem is improved, but the noise cannot be ignored. Occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a piezoelectric bimorph fan which eliminates vibration propagation loss, improves air blowing efficiency, and reduces weight and noise. .

[0007]

(1) According to the present invention, one end of a bimorph elastic portion to which a sine wave is applied is interposed between a pair of piezoelectric members arranged opposite to each other, and the other end of the bimorph elastic portion is provided at the other end of the bimorph elastic portion. A piezoelectric bimorph fan provided with a vibrating part,
Among the bimorph elastic portion and the vibrating portion, at least the bimorph elastic portion is formed of a unidirectional carbon fiber composite material, and the bimorph elastic portion and the vibrating portion are integrally formed of a unidirectional carbon fiber composite material. Wherein the carbon fiber direction of the unidirectional carbon fiber composite material is matched with the length direction of the piezoelectric bimorph fan.

(2) The unidirectional carbon fiber composite material comprises:
It is lighter than metal such as iron which has been conventionally used as a bimorph elastic part, and the rigidity in the length direction is improved.
When the bimorph elastic portion and the vibrating portion are integrally formed of a unidirectional carbon fiber composite material, no vibration propagation loss occurs, and the blowing efficiency is improved. Moreover, since it is lightweight, there is no problem of noise. Further, when the carbon fiber direction of the unidirectional carbon fiber composite material is aligned with the length direction of the piezoelectric bimorph fan, unnecessary vibration in the width direction can be suppressed, and efficient driving can be performed.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same parts as those in FIG. 2 are denoted by the same reference numerals. 1 is different from FIG. 2 in that a unidirectional carbon fiber composite material, for example, an anisotropic carbon fiber composite material 11 is used instead of the metal plate 1 (that is, the bimorph elastic portion) and the vibration plate 4 (that is, the vibration portion). And piezoelectric ceramics 2a, 2b
The other parts are shown in Fig. 2
It is configured identically.

The direction of polarization of the piezoelectric ceramics 2a and 2b is as shown in the figure, and the lower piezoelectric ceramics 2b is contracted when the upper piezoelectric ceramics 2a is expanded, so that the anisotropic carbon fiber composite material 11 has a polarity of voltage. Bending vibration is performed accordingly.

Since one end of the element is fixed by the fixing jig 3, a sinusoidal wave of the resonance frequency of the bimorph element is applied from the AC voltage source 5, so that the tip of the anisotropic carbon fiber composite material 11 is fanned. Vibrating in the shape of a letter.

The anisotropic carbon fiber composite material 11 is a material obtained by compounding carbon fibers having uniform orientation with an epoxy resin or the like. Since the anisotropic carbon fiber composite material is lighter and stronger than metals such as iron, it is most suitable as a fan fan vibration material. Further, the carbon fiber composite material is conductive and can be used instead of the base metal plate of the piezoelectric bimorph.

In this embodiment, since the bimorph elastic portion and the vibrating portion have an integral structure made of the anisotropic carbon fiber composite material 11, there is no vibration propagation loss and the air blowing efficiency is good. Moreover, since the anisotropic carbon fiber composite material is lightweight, there is no problem of noise.

Further, by aligning the carbon fiber direction of the anisotropic carbon fiber composite material 11 with the length direction of the piezoelectric bimorph fan, the piezoelectric bimorph can suppress unnecessary vibration in the width direction, and can efficiently perform the piezoelectric bimorph operation. The fan can be driven.

Further, the present invention is not limited to the case where the bimorph elastic portion and the vibrating portion are integrally formed of a unidirectional carbon fiber composite material, but the bimorph elastic portion is formed of a unidirectional carbon fiber composite material, and the vibrating portion transmits vibration. It may be made of another material having no loss.

[0016]

(1) As described above, according to the present invention, the propagation loss of vibration does not occur, and the blowing efficiency is improved. Moreover, since it is lightweight, there is no problem of noise.

(2) According to the present invention, unnecessary vibration in the width direction can be suppressed, and efficient driving can be performed.

[Brief description of the drawings]

FIGS. 1A and 1B show an embodiment of a piezoelectric bimorph fan according to the present invention, wherein FIG.

FIG. 2 shows an example of a conventional piezoelectric bimorph fan,
(A) is an overall configuration diagram, (b) is a sectional view of a main part.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Metal plate, 2a, 2b ... Piezoelectric ceramics, 3 ... Fixing jig, 4 ... Vibration plate, 5 ... AC voltage source, 11 ... Anisotropic carbon fiber composite material.

Claims (4)

[Claims] 1. A piezoelectric bimorph fan comprising a pair of piezoelectric members disposed opposite to each other, one end of a bimorph elastic portion to which a sine wave is applied interposed, and a vibrating portion provided at the other end of the bimorph elastic portion. A piezoelectric bimorph fan, wherein at least the bimorph elastic part of the bimorph elastic part and the vibrating part is made of a unidirectional carbon fiber composite material. 2. The piezoelectric bimorph fan according to claim 1, wherein the bimorph elastic part and the vibrating part are integrally formed of a unidirectional carbon fiber composite material. 3. The piezoelectric bimorph fan according to claim 1, wherein a carbon fiber direction of the unidirectional carbon fiber composite material is aligned with a length direction of the piezoelectric bimorph fan. 4. The piezoelectric bimorph fan according to claim 2, wherein a carbon fiber direction of the unidirectional carbon fiber composite material is aligned with a length direction of the piezoelectric bimorph fan.