JP3489618B2 - Piezoelectric generator - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a piezoelectric power generation device using a piezoelectric ceramic element.

[0002]

BACKGROUND OF THE INVENTION Piezoelectric materials have a variety of applications as conversion elements between mechanical energy and electrical energy. Many materials, both inorganic and organic, are known to have a piezoelectric effect, but PZT-based (piezoelectric) ceramics are currently in practical use.
C ceramics).

A piezoelectric ceramics element is an element in which a high voltage of direct current is applied to a polycrystal to generate remanent polarization so as to have piezoelectricity, and the basic piezoelectric constant can be changed quite freely depending on the composition. , Its versatile. In particular, lead zirconate titanate-based piezoelectric ceramic elements have a wide composition range and wide selection range of additives, and a wide range of applications.

FIG. 6 is an explanatory view of a piezoelectric power generating device according to a conventional example. This piezoelectric power generator has a substrate 3 such as an acrylic material.
The piezoelectric ceramic element plate 31 is bonded to the substrate 2, and both ends of the substrate 32 are fixed by holders 33 made of a hard material such as metal. Then, a steel ball 35 is dropped from above the ceramic element plate 31 to apply mechanical impact energy due to a collision to the piezoelectric element plate 31 to excite flexural vibration in the piezoelectric element plate 31 including the substrate 32. It extracts electrical energy.

[0005]

Although the PZT-based piezoelectric ceramic element is expected to have practicality, it has a problem that it is not practical as a piezoelectric power generation device because of a small amount of power generation. Further, in the piezoelectric power generation device using the piezoelectric ceramics element, it is indispensable to continue the natural vibration of the piezoelectric ceramics element plate 31 as long as possible. For this purpose, the piezoelectric ceramics element plate 3
There was also a problem that the natural vibration of No. 1 had to realize a support structure without mechanical resistance.

Further, in the above-mentioned conventional technique, since the substrate 32 and the piezoelectric ceramics element plate 31 are made of different materials,
It is difficult to bring the center of vibration (the part that does not expand or contract) to the joint surface between the substrate 32 and the piezoelectric ceramics element plate 31, and when this center appears on the piezoelectric ceramics element plate 31, cancellation in polarization occurs. It also had a problem that the power generation efficiency was lowered.

The present invention was devised in view of the current situation, and its object is to have a simple structure.
Piezoelectric generator capable of significantly improving power generation efficiency
Is to provide.

[0008]

In order to achieve the above object, a piezoelectric power generation device according to the present invention is a piezoelectric power generation device that generates electric power by applying strain deformation to a piezoelectric ceramic plate formed in a plate shape. Piezoelectric ceramic plate 1
Piezoelectric ceramic elements 1a, 1 formed in two plate shapes
b is formed into a layer by directly joining with the polarization reversed , and generating electricity.
While increasing efficiency, the central portion or both end portions of one surface of the piezoelectric ceramic plate 1 is supported by the cushion material 3,
The piezoelectric ceramic plate 1 is characterized by having a flexible support structure in which natural vibration of the piezoelectric ceramic plate 1 is difficult to be transmitted to other structures.

In the piezoelectric power generator according to the present invention, the piezoelectric ceramic plates 1 supported by the cushion member 3 are arranged face to face, and the piezoelectric ceramic plates 1 and 1 are reciprocally moved between the piezoelectric ceramic plates 1 and 2 to move the piezoelectric ceramic plates. A hard striking body 4 for striking the ceramic plates 1, 1 is provided.

Further, in the piezoelectric power generation device according to the present invention, the piezoelectric ceramic plate 1 supported by the cushion material 11 is arranged, and one or both sides of the piezoelectric ceramic plate 1 are connected to the piezoelectric ceramic plate 1. The hard striking body 4 that reciprocates to strike the piezoelectric ceramic plate 1 is provided.

In addition to this, the two piezoelectric ceramic elements 1a and 1b are formed in the same form.

Also, the above-mentioned two piezoelectric ceramic elements 1
This means that each of a and 1b is joined in a plurality of layers.

Further, the above-mentioned two piezoelectric ceramic elements 1
This means that each of a and 1b is joined in a plurality of layers. Further, a lead zirconate titanate-based material is used for the piezoelectric ceramic elements 1a and 1b.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings.

In FIG. 1, piezoelectric ceramic plates 1 are arranged on both ends of a cylindrical container 8 whose both ends are closed, and the piezoelectric ceramic plates 1 are hit with steel balls 4 to generate electricity. The cushion plate 3 is adhered to one side surface of the container 8 with the adhesive material 6, and the piezoelectric ceramics plate 1 is adhered to the central portion of the cushion plate 3 with the adhesive material 5. Container 8
Similarly, the piezoelectric ceramic plate 1 is adhered to the other side surface of the both, and both are opposed to each other. The protector plate 2 is fixed to the central portions of the surfaces of the piezoelectric ceramic plates 1 that face each other. The pipe 7 is placed between the piezoelectric ceramic plates 1.
And the steel ball 4 which can roll freely is provided in the pipe 7.

The piezoelectric ceramic plate 1 comprises two plate-shaped piezoelectric ceramic elements 1a and 1b having the same shape (the same material, the same shape, and the same thickness).
The a and 1b are joined by reversing the polarities of polarization.
By joining the ceramic elements 1a and 1b having the same shape, the two ceramic elements 1a and 1b undergo flexural vibration about the joining surface as a center (a portion that does not expand or contract). In this case, when the ceramic element 1a on one side expands, the ceramic element 1b on the other side contracts, and the electrodes for the output voltage are in the same direction, so that both piezoelectric ceramic elements 1a and 1b are connected in series. Becomes

When flexural vibration is performed around the joint surface, the piezoelectric ceramic element 1a (or 1b) on one side both expands and contracts, so that the polarization is not canceled and the piezoelectric ceramic element 1a is efficient. Power is generated. The electric current as generated electric energy is taken out using the lead wire 9.

Although two piezoelectric ceramic elements 1a and 1b are laminated here, each piezoelectric ceramic element 1
Each of a (1b) can have a laminated structure.
In this laminated structure, a plurality of thin piezoelectric ceramic plates are joined (in this case, the polarities of polarization are the same) to form one piezoelectric ceramic element 1a (or 1b). In this way, by adopting a laminated structure, when bonded with an adhesive having elastic properties, for example, due to this elastic effect, bending of a ceramic plate material lacking in material strength can be facilitated and bending strength can be maintained. Also, by making it thinner, the ceramic plate becomes more resistant to bending. The outer shape of the piezoelectric ceramic plate 1 is not particularly limited, but a circular shape,
There are oval, triangular, quadrangular or polygonal shapes.

The cushion plate 3 is made of a synthetic resin material, a rubber material, or a sponge-like soft material. The reason why the piezoelectric ceramic plate 1 is fixed by using the cushion plate 3 and only the central portion of the cushion plate 3 with the adhesive 5 is that the vibration of the piezoelectric ceramic plate 1 is not attenuated. When the piezoelectric ceramic plate 1 vibrates, the member that supports the piezoelectric ceramic plate 1 becomes a factor that damps the vibration of the piezoelectric ceramic plate 1. In order to remove this damping factor, the cushion plate 3 is used as much as possible. Leave 1 free.

As in the present invention, the piezoelectric ceramic plate 1
The strain becomes a natural vibration of the piezoelectric ceramic itself and continues for a while. In order to continue this natural vibration for a long time, it is important that this natural vibration is not transmitted to any structure other than the piezoelectric ceramic plate 1. The natural vibration of the piezoelectric ceramic plate 1 is converted into electric energy, but the vibrations of the other structures all become mechanical resistance and absorb the natural vibration energy and cannot be extracted as electric energy. Therefore, in the present invention, by using the cushion plate 3 as a means for realizing a soft contact between the piezoelectric ceramic plate 1 and another structure so that the natural vibration is not transmitted, the piezoelectric ceramic plate 1 The natural vibration of No. 1 can be continued for a long time, and the power generation efficiency is improved. Of course, this cushion material 3
Also has a function of alleviating an impact applied to the piezoelectric ceramic plate 1. The protector plate 2 is made of metal, synthetic resin or the like, and protects the piezoelectric ceramic plate 1 from hitting the steel ball 4.

When the piezoelectric generator is placed in an environment of a predetermined motion state utilizing wind, waves, or human action, the steel ball 4 rolls in the pipe 7 and left and right piezoelectric ceramics. The plate 1 is hit and the impact energy due to the collision is applied. Then, vibration is excited in the piezoelectric ceramic plate 1,
Expansion and contraction are repeated to generate AC electricity.

The steel ball 4 is used as a hitting body here.
Was arranged in the pipe 7 to strike the piezoelectric ceramic plate 1. However, the material and shape of the striker are not limited to steel balls, but other heavy objects such as columnar shapes and egg shapes. May be Further, not only the pipe 7, but also the striking body may move along the rail as long as the striking body can freely move. Otherwise, use a spring material in place of the pipe 7 (-out upper direction or lower direction), the spring member one end is fixed in the mounting the steel ball 4 at its other end, on both sides by lateral swinging of the spring member Alternatively, the piezoelectric ceramic plate 1 may be hit.

FIG. 2 shows a circuit of a charging device for charging the electricity generated by the power generating device using the piezoelectric power generating device. This charging device includes PZT1 and PZT2 as two piezoelectric ceramic plates 1, rectifying diodes D1 to D6, a capacitor C for storing electricity, and a switch S.
W and light emitting diodes L1 to L3. Electricity generated by PZT1 is full-wave rectified by diodes D1 to D3, and electricity generated by PZT2 is diode D4.
Full-wave rectification is performed by D6. The full-wave rectified electricity is charged in the capacitor C. And switch S
By the operation of W, the capacitor C is discharged and the light emitting diodes L1 to L3 are turned on.

FIG. 3 shows an example of a piezoelectric power generator using one piezoelectric ceramic plate 1. This piezoelectric power generation device uses a cylindrical container 12 whose both ends are closed.
Cushion members 11 are arranged on the upper surface and the lower surface of the central portion of the above, and the piezoelectric ceramic plates 1 (1a, 1b) are fitted and supported in the recesses of these cushion members 11. Protector plates 2 are attached to both surfaces of the piezoelectric ceramic plate 1. Pipes 7 are arranged on both sides of both piezoelectric ceramic plates 1, and rolling steel balls 4 are provided in these pipes 7. The material of the cushion member 11 is the same as that of the cushion plate 3, and the other members are also as described above.

[0025] the piezoelectric power generating device, I place the environment of a given motion state, the steel ball 4 are rolling in the pipe 7 to beat the piezoelectric ceramic plate 1 alternately, the piezoelectric ceramic plate 1 is vibration excitation The expansion and contraction are repeated to generate AC electricity.

FIG. 4 shows an example of a wind-bell-shaped piezoelectric generator. In this piezoelectric power generation device, piezoelectric ceramic plates 1 are attached to two positions (three or more positions are possible) on the inner peripheral surface of a bell-shaped container 14 so as to face each other. At the time of attachment, the cushion plate 3 is adhered 6 to the inner peripheral surface, and the piezoelectric ceramic plate 1 is adhered only to the central portion of the cushion plate 3 using the adhesive material 5. Similarly, the piezoelectric ceramic plates 1 are arranged on the surfaces facing each other, and the protector plate 2 is attached to the central portion of the facing surfaces of both piezoelectric ceramic plates 1.

Then, the steel ball 4 is suspended in the container 14 with the hanging thread 15.
And the flat member 16 and the like are hung from the steel ball 4. The material and the like of each member are as described above. The piezoelectric power generating device, if you put in an environment with air, the steel ball 4 beat piezoelectric ceramic plate 1 swings, the piezoelectric ceramic plate 1 is generating an alternating electric.

FIG. 5 shows an example of a piezoelectric power generation device using a spring material. In this piezoelectric power generation device, a steel ball 4 is suspended by using a spring material 18, a cushion plate 3 is arranged below the steel ball 4, and the piezoelectric ceramic plate 1 is fixed to the cushion plate 3 only by using an adhesive 5 at a central portion thereof. Then, this piezoelectric ceramic plate 1
The protector plate 2 is fixed to the central portion of the. The material and the like of each member are as described above. The piezoelectric power generating device, place the environment of a given motion state, the steel ball 4 by stretching movement of the spring member 18 is pummeled piezoelectric ceramic plate 1, the piezoelectric ceramic plate 1 vibration is excited to generate electricity.

Further, for example, a wind turbine type piezoelectric power generating device may be used. In this wind turbine type piezoelectric power generating device, the piezoelectric ceramic plate 1 is formed by using the cushion plate 3 and the adhesive material 5 on the surfaces of the radially formed surfaces in the same manner as described above.
Then, the wind turbine is rotated by using the wind force, and the piezoceramic plate 1 that rotates and moves continuously hits the steel balls 4 movably attached to one end of the spring material or the like to generate electricity. In addition to the above, various piezoelectric power generation devices can be considered.

Therefore, according to the piezoelectric power generation device of the above-described embodiment, the piezoelectric ceramic plate 1 is formed by laminating the plate-shaped ceramic elements, so that the power generation efficiency is improved, and the piezoelectric power generation device is used as the power source of the charging device or the light emitting device. It is valid.
The piezoelectric power generation device has a simple structure and is economical, so that it is expected to be used practically. For example, if this piezoelectric power generation device is mounted on a bicycle or shoes and the light emitting diode is turned on, it can be used as a device for recognizing the presence at night. Also, if mounted on a battery-powered wristwatch or mobile phone, etc., instead of a battery,
Alternatively, it can be used as a measure against battery exhaustion. Furthermore, buoys (buoys) are generated by using the shaking of the waves to generate electricity.
Can be expected to be used as a lighting device.

[0031]

As described above, according to the piezoelectric power generator of the present invention, two plate-shaped piezoelectric ceramic elements are bonded to each other to form a layered piezoelectric ceramic plate. Since the structure in which a metal plate or the like is not interposed between the piezoelectric ceramic elements of No. 1, the natural vibration of the piezoelectric ceramic element is not attenuated by the intervening product such as the metal plate, so that the vibration of the piezoelectric ceramic plate is continued for a long time. It is possible to obtain the effect that the power generation efficiency is significantly improved.

Further, since the structure in which the layered piezoelectric ceramic plate is supported by the cushion material is adopted, since the vibration of the piezoelectric ceramic plate lasts for a long time, the effect of improving the power generation efficiency can be obtained.

Further, according to the piezoelectric power generator of the present invention, the structure in which the central portion or both end portions of the layered piezoelectric ceramic plate is supported by the cushion material is adopted, and the piezoelectric ceramic plate and other structures are connected. Since the support is soft so that the natural vibration is not transmitted between the piezoelectric ceramic plates, the vibration of the piezoelectric ceramic plate continues for a long time and the power generation efficiency is significantly improved.

Further, in the piezoelectric power generating device according to the present invention, since the protector plate is attached to the hitting portion of the piezoelectric ceramics plate, the piezoelectric ceramics element is effectively protected against the hitting. . In addition, since each of the piezoelectric ceramic elements is bonded in a plurality of layers, there is an effect that the strength of the piezoelectric ceramic element can be maintained. In addition, titanium is used as a piezoelectric ceramic element.
Since a lead zirconate acid-based material is used, it has a wide application range as a power generation device and is effective for practical use.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a piezoelectric power generation device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of the charging device.

FIG. 3 is an explanatory diagram showing a piezoelectric power generation device using one piezoelectric ceramic plate according to another embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a wind-bell-shaped piezoelectric power generation device according to still another example of the present embodiment.

FIG. 5 is an explanatory view showing a piezoelectric power generating device using a spring material according to still another embodiment of the present invention.

FIG. 6 is an explanatory diagram of a piezoelectric power generation device according to a conventional example.

[Explanation of symbols]

1 Piezoelectric ceramic plate 1a, 1b Piezoelectric ceramic element 2 protector plates 3,11 Cushion material (cushion plate) 4 Strike body (steel ball)

Continuation of front page (56) Reference JP-A-11-136964 (JP, A) JP-A-5-64418 (JP, A) JP-A-55-20459 (JP, A) JP-A-52-9388 (JP , A) JP 11-146663 (JP, A) JP 2000-287464 (JP, A) JP 3-106084 (JP, A) Actual development Sho 56-132457 (JP, U) Actual public Sho 49 −40285 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02N 2/00 H01L 41/113

Claims (6)

(57) [Claims] 1. A piezoelectric power generation device for generating electric power by applying strain deformation to a piezoelectric ceramic plate formed in a plate shape, wherein the piezoelectric ceramic plate is polarized by a piezoelectric ceramic element formed in two plate shapes. In the opposite direction, they are directly joined to form a layered structure, and the central portion or both end portions of one surface of this piezoelectric ceramic plate are supported by a cushion material,
A piezoelectric power generating device having a flexible support structure in which natural vibration of the piezoelectric ceramic plate is difficult to be transmitted to other structures. 2. The piezoelectric ceramic plates supported by the cushion material are arranged face to face, and a hard striking body for striking each piezoelectric ceramic plate by reciprocating between the piezoelectric ceramic plates is disposed between the piezoelectric ceramic plates. The piezoelectric power generation device according to claim 1, wherein 3. A hard striking body for striking the piezoelectric ceramic plate by reciprocating between the piezoelectric ceramic plate and one or both sides of the piezoelectric ceramic plate supported by the cushion material. The piezoelectric power generation device according to claim 1, which is characterized in that. 4. The piezoelectric ceramic elements of the two sheets are formed in the same shape, as claimed in any one of claims 1 to 3.
The piezoelectric power generation device according to any one of 1. 5. The piezoelectric power generation device according to claim 1, wherein each of the two piezoelectric ceramic elements is bonded in a plurality of layers. Wherein titanium as a piezoelectric ceramic element
The piezoelectric power generator according to any one of claims 1 to 5 characterized by using a phosphate zirconate-lead-based material.