JPH0656159B2 - Blade mechanism of piezoelectric blower - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an air blower suitable for blowing a small amount of air, and in particular, it uses a bending displacement of a piezoelectric bimorph element to generate wind in a flap portion. TECHNICAL FIELD The present invention relates to improvement of a blade mechanism of a piezoelectric blower.

[Prior Art] For example, in an electronic device such as a computer, there is a situation where heat is locally generated, so that a blower is attached to radiate heat. The blower in this case is 0.3m
It is desirable to use a small and low noise type because the air flow rate of about ³ / min is sufficient.

As those satisfying such conditions, those shown in FIGS. 8 and 9 and FIG. 10 have been proposed. First, in FIG. 8 and FIG. 9, the blade 1 of the blower is
This is a piezoelectric bimorph element that utilizes the piezo effect, and is formed by stacking the piezoelectric elements 2 on top of each other, and a sheet-like flap portion 3 is formed at the tip thereof. Further, in FIG. 9, one set of the blades 1 as described above is prepared, and one end of each of the blades 1 and 1 is attached to the support plate 4. In this state, the blades 1 and 1 are arranged in a V shape that gradually increases as the distance between the blades 1 and 1 approaches the flap portion 3.

Then, the bimorph element 2 is bent and displaced by the application of the voltage, and the flap portion 3 vibrates like the wing of a flying bird. This causes wind to be blown in the direction indicated by the arrow.

[Problems to be Solved by the Invention] However, since the size of the flank portion 3 of the blade 1 is limited, in the former case, the generation rate of wind is limited, and the amount of air blown is a predetermined criterion. The reality is that it is difficult to reach.

Further, in the latter case, although the amount of air blown is compensated, the space between the flap portions becomes wide and bulky, so that there is a disadvantage that it tends to take up a lot of space and hinders the overall size reduction. In addition, the cost is high because two piezoelectric bimorph elements 1 are required.

The present invention has been made in view of such circumstances, and an object thereof is not only low noise operation but also downsizing of the whole and low cost, yet it is possible to effectively generate wind and secure a predetermined reference air flow rate. It is an object of the present invention to provide a blade mechanism of a piezoelectric blower which is excellent.

[Means for Solving the Problems] In the present invention, a piezoelectric bimorph element having one end supported by a support member and the other end arranged along the air passage is opposite to the support member of the piezoelectric bimorph element. A flap portion mounted on the side for transmitting bending displacement of the piezoelectric bimorph element to generate a wind, and the flap portion has a plurality of flaps branching from the base end portion at predetermined angles with each other. Has been adopted.

[Operation] According to the present invention configured as described above, since a plurality of flaps are formed in the flap portion, the flaps vibrate with substantially the same amplitude as a voltage is applied to the piezoelectric bimorph element. , The wind generation rate is improved overall.

[Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

First, in FIG. 1 and FIG. 2, the casing 10 of the blower device has an air blow passage 10a formed therein, and a piezoelectric bimorph element 11 is arranged in the air blow passage 10a. This bimorph element 11 is formed by stacking a pair of piezoceramic plates 12, 12 made of lead zirconate titanate or the like, and in this state, the piezoceramic plate 12 and the lead-out plate 15
Are glued together. The piezoelectric ceramic plates 12 and 12 have the same polarization direction as indicated by an arrow P, and thin-film electrodes 13 and 14 are formed on the upper and lower surfaces by printing a metal having good conductivity such as silver, for example. There is. In addition, the piezo ceramic plate 12,
Reference numeral 12 sandwiches a lead-out plate 15 between electrodes 13 and 14 in a sandwich state, and one end of the lead-out plate 15 projects to the outside so as to be connected to a lead wire 16. The lead-out plate 15 has both the function of conducting and the function of reinforcing, and is formed of Kovar having a coefficient of thermal expansion corresponding to that of the piezoceramic plate 12. Furthermore, the lead-out plates 17 and 18 are provided as reinforcing plates on the surface portions exposed to the outside of the piezoceramic plates 12 and 12 to increase the rigidity of the entire bimorph element 11. In this state, one end of the bimorph element 11 has a pair of screws 19 and 19 attached to the casing 10.
Is clamped by a conductive support member 20, and the other end is fitted with a U-shaped clamp portion 21. The above-mentioned clamp portion 21 constitutes a flap portion 22 which will be described later, and is made of elastic synthetic resin such as polyethylene terephthalate. Further, from the clamp portion 21, rectangular plate-shaped flaps 23 are integrally formed, for example, only three flaps have an angular interval of 30 degrees from each other, and are incorporated in the flap portion 22.

Next, the operation of the above configuration will be described.

Between the lead wire 16 and the electrodes 13 and 14, for example, 100
When an AC power source of V / 50 Hz is applied, the piezo effect causes the piezoceramic plates 12 and 12 of the bimorph element 11
Bends alternately around the longitudinal direction thereof, and this displacement is transmitted to the flap 23 via the clamp portion 21. Therefore, when the flaps 23 of the flap portion 22 fly, the birds vibrate as if they flap their wings, and wind is generated in the air passage 10a to blow air from the discharge port (not shown) in the direction indicated by the arrow W. This allows the heat generated from electronic components such as computers to be dissipated,
The heating condition can be avoided and the intended function is maintained.

As described above, according to the above-described configuration, since the bimorph element 11 is bent and displaced, unlike the case of driving an electric motor, low noise is achieved, and a plurality of flaps 2 are used.
Since each of the 3 vibrates with the same amplitude, the wind generation rate is improved, and the amount of blown air satisfying the predetermined standard is obtained. Nevertheless, the flap 23 is a plate material that is simply branched into a plurality, which is advantageous in terms of cost.
Since it does not occupy any space, the overall downsizing is maintained and the compact state is maintained.

By the way, FIG. 3 is a graph showing the blowing characteristics, where the vertical axis is the air flow rate V and the horizontal axis is the opening angle θ formed by the flap 23.
I am trying. According to this graph, as the number N of flaps 23 increases, the air flow rate V tends to increase as a whole, and when the angle θ is 30 degrees regardless of the number N of flaps 23, the maximum air flow V increases. It can be seen that the air volume can be obtained.

This is because when the angle is less than θ = 15 °, the amount of air blown decreases sharply due to the interference between the flaps, and when the angle θ exceeds 60 °, the direction of air blow does not match and the amount of air blown decreases sharply. Therefore, in the vicinity of θ = 30 °, there is little interference between the flaps, the air blowing directions are substantially the same, and the air blowing amount is maximum.

In this case, the effective length A of the piezoelectric bimorph element 11 is 2
5 mm, the thickness B of the clamp portion 19 is 10 mm, the flap 2
The length C of 3 is set to 41 mm, and the width D of the flap 23 is set to 22 mm. At this time, since the three flaps 23 are set to have the same size, a large amplitude can be obtained due to resonance, which is advantageous in terms of the wind generation rate.

Next, second to fifth embodiments of the present invention will be sequentially described.

In the second embodiment, as shown in FIG. 4, the lead plates 17 and 18 of the first embodiment are omitted, and the bimorph element 11 is used.
This may be done if the rigidity of the device itself can withstand use, and the lead-out plates 17 and 18 described above may be provided as necessary.

In the third embodiment, as shown in FIG. 5, the flap member 25 of the flap portion 24 is formed in a trapezoidal shape in which the width gradually increases outward from the base end portion. In this case, the area of the flap portion 24 is increased, which is advantageous in terms of the wind generation rate as compared with the first embodiment, but the shape of the flap portion is not limited to the trapezoidal shape, and various shapes can be used as necessary. Of course, the shape can be changed.

In the fourth embodiment, as shown in FIG. 6, the polarization directions of the piezoceramic plates 12, 12 in the piezoelectric bimorph element 11 are made to face each other as indicated by arrows P, Q. In this case, the lead wire 26 is connected to the piezoelectric ceramic plates 12, 12
Is connected to the electrodes 13 and 14 exposed to the outside.

In the fifth embodiment, with the polarization directions of the piezoceramic plates 12, 12 being the same as in the fourth embodiment, as shown in FIG. 7, the lead-out plates 27, 27 are used as reinforcing plates for the same purpose as in the first embodiment. By using this, the rigidity of the entire piezoelectric bimorph element 11 is increased. Then, the lead wires 28, 28 are connected to the lead-out plate 27,
It is connected to the electrodes 13 and 14 via 27.

Even if it is configured as in the second to fifth embodiments, the same effect as in the first embodiment can be obtained. In this case, in each embodiment, the same members as those in the first embodiment are designated by the same reference numerals and only different portions are described.

The electrodes 13 and 14 may be not only a metallic material such as silver but also aluminum or nickel, and the point is that the material has good electrical conductivity. Further, the formation of the electrodes 13 and 14 is not limited to printing but may be vapor deposition or plating. Furthermore, the branched shape at the base end portion of the flap is not limited to the V-shape, but may be formed in the U-shape. At this time, the angle formed by the flaps and the number of flaps are not limited to 30 degrees or three, but can be set arbitrarily. In addition, in the piezoelectric bimorph element 11, the piezoelectric ceramic plates 12 and 12, the electrodes 13 and 14, and the lead-out plate may be held not only by sandwiching but also by bonding. Further, the object of application is not only electronic components of computers, but also widely used for blowers for convection formation in microwave ovens. In addition, the piezoceramic plate is not limited to lead zirconate titanate, and can be variously changed in concrete implementation.

As described above, according to the present invention, not only low noise operation,
It is advantageous in terms of cost and can be downsized as a whole, yet it has an excellent effect that wind can be effectively generated and a predetermined reference air flow rate can be secured.

[Brief description of drawings]

FIGS. 1 to 7 show first to fifth embodiments of the present invention, respectively. FIG. 1 is a perspective view, FIG. 2 is a longitudinal sectional view, and FIG. 3 is a graph showing the characteristics of air flow, FIG. 4 is a view corresponding to FIG. 2, FIG. 5 is a front view, FIG. 6 is a view corresponding to FIG. 2, FIG. 7 is a view corresponding to FIG. 2, and FIGS. FIG. 8 is a perspective view, FIG. 9 is a longitudinal sectional view, and FIG.
The figure is a top view. In the figure, 11 ... Piezoelectric bimorph element, 12 ... Piezoceramic plate, 13, 14 ... Electrodes, 22, 24 ... Flap portion, 23, 25 ... Flap element

Claims (4)

[Claims] 1. A piezoelectric bimorph element, one end of which is supported by a support member and the other end of which is arranged along an air flow path, and the piezoelectric bimorph element which is attached on the opposite side of the support member of the piezoelectric bimorph element. Of the piezoelectric blower, which comprises: a flap portion that transmits the bending displacement of (1) to generate a wind; and the flap portion has a flap element that branches from the base end portion into a plurality of angles at a predetermined angle. Blade mechanism. 2. The piezoelectric blower according to claim 1, wherein an angle formed by adjacent flaps of the flap portion is within a range of 15 degrees to 60 degrees. Blade mechanism. 3. The blade mechanism of the piezoelectric blower according to claim 2, wherein the angles formed by adjacent flaps of the flap portion are 30 degrees. 4. The piezoelectric blower according to any one of claims 1 to 3, wherein the number of flaps in the flap portion is in the range of 2 to 5. Blade mechanism.