WO2012073741A1 - Piezoelectric power generating device - Google Patents

Abstract

A piezoelectric power generating device that is readily produced and capable of retrieving large power is provided. The piezoelectric power generating device (1) has a second piezoelectric power generating plate (7) arranged so as to face a first piezoelectric power generating plate (2); the first and second piezoelectric power generating plates (2, 7) are coupled by coupling members (8, 9); and a support member (10) is disposed on the first piezoelectric power generating plate (2) for fixing said device externally.

Description

Piezoelectric generator

The present invention relates to a piezoelectric power generation device that can take out electric power when vibration or external force is applied from the outside using the piezoelectric effect, and more specifically, has a structure formed by connecting a plurality of piezoelectric power generation plates. The present invention relates to a piezoelectric power generation device having the same.

Conventionally, various piezoelectric generators using the piezoelectric effect have been proposed. For example, Patent Literature 1 below discloses a piezoelectric power generation device 1001 shown in FIG.

The piezoelectric power generation device 1001 has a metal plate 1002 bent into a U shape. At least one piezoelectric element 1003 is fixed to the metal plate 1002. One end of the metal plate 1002 is fixed to the fixing member 1004. The metal plate 1002 bent in a U shape has a first arm portion 1002 a fixed to the fixing member 1004. The metal plate 1002 is bent at the end of the first arm 1002a opposite to the end fixed to the fixing member 1004. The second arm portion 1002c is connected to the first arm portion 1002a via the bent intermediate portion 1002b. The tip of the second arm portion 1002c is a free end.

Since the piezoelectric power generation apparatus 1001 uses the metal plate 1002 bent in a U shape as described above, when vibration or external force is applied from the outside, the free end is greatly displaced, and relatively large power is generated. It is supposed to be possible.

Further, the following Patent Document 2 discloses a piezoelectric power generation apparatus using a piezoelectric power generation plate that is folded back and forth in a plurality of zigzag shapes. Also here, it is said that by using the piezoelectric power generation plate folded back in a zigzag manner, a large amount of electric power can be generated when external vibration or external force is applied.

Special table 2010-517285 gazette JP 2005-507627 A

By the way, depending on the application field of the piezoelectric power generation device, the vibration applied to the piezoelectric power generation device may have a relatively low frequency. For example, in a piezoelectric power generation device attached to an automobile or a piezoelectric power generation device that generates power using vibrations when a person walks, it is necessary to generate electric power in the piezoelectric power generation device by vibration at a relatively low frequency. In a piezoelectric power generation device, when generating electric power by low-frequency vibration, it is necessary to lower the resonance frequency of the piezoelectric power generation element.

Therefore, when a piezoelectric power generation plate, which is a plate-like piezoelectric power generation element, is used, a method of reducing the thickness is used to lower the resonance frequency of the piezoelectric power generation plate. However, when the thickness of the piezoelectric power generation plate is reduced by using a piezoelectric power generation plate that is folded back in a U shape or is folded back in a zigzag manner, as described in Patent Document 1 or Patent Document 2. As a result, the strength of the folded portion decreases, and plastic deformation and brittle fracture occur. Therefore, it has been difficult to reduce the thickness of the piezoelectric power generation plate. Further, in the piezoelectric power generation device 1001 described in Patent Document 1, the piezoelectric element 1003 is attached to only a part of the metal plate 1002. Therefore, since the ratio of the piezoelectric elements in the piezoelectric power generation plate is small, the power generation amount cannot be sufficiently increased.

Further, in the piezoelectric power generation device described in Patent Document 2, a zigzag-shaped piezoelectric power generation plate has to be processed, and the processing process is very complicated. Further, in such a complicated shape piezoelectric power generation plate, the work of polarization processing in partially different directions has been complicated.

An object of the present invention is to provide a piezoelectric power generation apparatus that is easy to manufacture and that can extract a large amount of electric power even when low-frequency vibration is applied, and a manufacturing method thereof.

The piezoelectric power generation device according to the present invention includes a first piezoelectric power generation plate, a second piezoelectric power generation plate disposed so that the principal surfaces of the first piezoelectric power generation plate face each other, and the first and first piezoelectric power generation plates. A piezoelectric power generation element having a connecting member connecting two piezoelectric power generation plates, and a support member fixed to the first piezoelectric power generation plate and fixing the piezoelectric power generation element to the outside.

In a specific aspect of the piezoelectric power generation device according to the present invention, a plurality of the piezoelectric power generation elements are connected, and in the two piezoelectric power generation elements connected to each other, the second piezoelectric power generation of one piezoelectric power generation element. The other piezoelectric power generating element is connected to the main surface of the plate opposite to the main surface facing the first piezoelectric power generating plate. In this case, since it has a plurality of piezoelectric power generation elements, large electric power can be obtained.

In still another specific aspect of the piezoelectric power generation device according to the present invention, in the structure in which the plurality of piezoelectric power generation elements are connected, the support member is connected to a central portion or both ends of the first piezoelectric power generation plate. The connecting member is connected to the first and second piezoelectric power generation plates at the center or both ends of the first and second piezoelectric power generation plates. In this case, the bending moment acting on the support member or the connecting member formed in the central portion of the piezoelectric power generation plate can be reduced. Therefore, the stress that acts on the central portion of the piezoelectric power generation plate can be reduced.

In the piezoelectric power generation device according to the present invention, the first and second piezoelectric power generation plates preferably have a rectangular shape.

In another specific aspect of the piezoelectric power generating device according to the present invention, the connecting member is configured such that the first piezoelectric power generating plate and the second piezoelectric power generating plate are positioned at both ends of the main surface facing each other. Including the first and second connection members for connecting the piezoelectric power generation plate and the second piezoelectric power generation plate, and the support member is opposite to the side on which the first and second connection members are provided. The main surface is provided at the center of the main surface of the first piezoelectric power generation plate. In this case, the piezoelectric power generation device can be supported at the center of the upper surface of the first piezoelectric power generation plate. Since there is one fixing portion, it is possible to easily fix to other parts and members.

In still another specific aspect of the piezoelectric power generation device according to the present invention, the connecting member is configured such that the first and second piezoelectric power generation plates are arranged at a central portion in the length direction of the first and second piezoelectric power generation plates. The support member is provided with first and second support members at both ends in the length direction of the main surface of the first piezoelectric power generation plate opposite to the side where the connection member is provided. ing. In this case, since the upper end of the first piezoelectric power generation plate can be fixed to another member, the fixing structure of the piezoelectric power generation device can be stabilized. In addition, since the first and second piezoelectric power generation plates are connected by a connecting member at the center of the main surface, that is, are connected at one place, the first piezoelectric power generation plate and the second piezoelectric power generation plate Can be displaced more greatly. Therefore, larger electric power can be taken out.

In still another specific aspect of the piezoelectric power generation device according to the present invention, in the first and second piezoelectric power generation plates, a cut extending from one long side of the rectangular piezoelectric power generation plate toward the other long side. A notch is formed. In this case, the amount of displacement of the piezoelectric power generation plate can be increased, so that even greater power can be taken out.

Preferably, a plurality of the notches are provided, and the plurality of notches are provided on two long sides alternately opposed in the length direction of the first and second piezoelectric power generation plates. . In this case, when a vibration or external force is applied from the outside, the piezoelectric power generation plate is displaced in a meander shape, and the resonance frequency can be further lowered. Therefore, much larger electric power can be taken out.

In still another specific aspect of the piezoelectric power generation device according to the present invention, a pair of opposite corner portions of the rectangular first and second piezoelectric power generation plates are respectively connected by the connecting member. The support member is fixed to the center of the first piezoelectric power generation plate. In this case, since the displacements in the length direction of the rectangular first and second piezoelectric power generation plates generated by the connecting portion and the support member are different from each other in the length direction, they are even larger. Electric power can be taken out.

In still another specific aspect of the piezoelectric power generation device according to the present invention, the first and second piezoelectric power generation plates have an outer peripheral edge from the inside of the piezoelectric power generation plate between the portions where the connecting members are provided. A notch that extends to is formed. In this case, since the notch is provided, the resonance frequency can be further lowered, and the amount of displacement when external vibration or external force is applied can be increased. Therefore, much larger electric power can be taken out. Preferably, a plurality of the cutout portions are provided, and the plurality of cutout portions are provided point-symmetrically with respect to a portion fixed to the support member. In this case, much larger electric power can be taken out.

In still another specific aspect of the piezoelectric power generation device according to the present invention, the piezoelectric power generation device is disposed on a main surface side opposite to the side on which the connection member is provided of the second piezoelectric power generation plate, A mass adding member fixed to the piezoelectric power generation plate is further provided. Since the mass addition member is provided, the displacement amount of the first and second piezoelectric power generation plates when vibration or external force is applied from the outside can be further increased. As a result, even greater power can be extracted.

In still another specific aspect of the piezoelectric power generation device according to the present invention, at least one piezoelectric power generation plate is disposed on a surface of the second piezoelectric power generation plate opposite to the first piezoelectric power generation plate via a connecting member. It is further connected. In this case, it is possible to extract a larger amount of electric power based on the displacement of more piezoelectric power generation plates.

In still another specific aspect of the piezoelectric power generation device according to the present invention, the first and second piezoelectric power generation plates are provided with a first polarization region polarized in the thickness direction and a first polarization region in the thickness direction. And a second polarization region subjected to polarization treatment in the opposite direction. Since the first and second polarization regions can be easily formed on the first and second piezoelectric power generation plates, the piezoelectric power generation device of the present invention can be configured without causing a complicated manufacturing process.

In still another specific aspect of the piezoelectric power generation device of the present invention, the piezoelectric power generation plate further includes a metal plate stacked on the piezoelectric plate, and a unimorph type piezoelectric element is configured. In this case, since it is a unimorph type, it is possible to increase the amount of displacement of the piezoelectric power generation plate when an external vibration or external force is applied. However, in the present invention, the piezoelectric power generation plate may be a bimorph type piezoelectric element.

In the piezoelectric power generation device according to the present invention, since the first piezoelectric power generation plate and the second piezoelectric power generation plate are connected via the connection member, vibration and external force are externally applied while being fixed to the outside by the support member. When applied, both the first and second piezoelectric power generation plates are displaced, and large electric power can be taken out. In addition, since it has only the structure which connected the 1st, 2nd piezoelectric power generation board via the connection member, it becomes possible to take out big electric power, without causing the complexity of a manufacturing process.

Furthermore, since the first and second piezoelectric power generation plates are connected via a connecting member, high power can be taken out without increasing the surface dimension of the piezoelectric power generation plate of the piezoelectric power generation device. Accordingly, it is possible to further reduce the size of the piezoelectric power generator.

FIG. 1A is a schematic front view of the piezoelectric power generation device according to the first embodiment of the present invention, and FIG. 1B shows the configuration of the piezoelectric power generation device according to the first embodiment of the present invention. FIG. 1C is a perspective view of the piezoelectric power generation apparatus according to the first embodiment of the present invention. FIGS. 2A and 2B are schematic front views for explaining the displacement state of the first and second piezoelectric power generation plates in the piezoelectric power generation apparatus according to the first embodiment of the present invention. . FIG. 3 is a schematic front view of the piezoelectric power generation apparatus according to the second embodiment of the present invention. FIG. 4A and FIG. 4B are schematic front views for explaining the displacement state of the first and second piezoelectric power generation plates in the piezoelectric power generation device according to the second embodiment of the present invention. . FIG. 5A and FIG. 5B are plan views of first and second piezoelectric power generation plates constituting a piezoelectric power generation apparatus according to the third embodiment of the present invention. FIG. 6 is a perspective view of a piezoelectric power generation apparatus according to the third embodiment of the present invention. FIG. 7A and FIG. 7B are plan views of first and second piezoelectric power generation plates that constitute a piezoelectric power generation device according to a fourth embodiment of the present invention. FIG. 8 is a perspective view of a piezoelectric power generating apparatus according to the fourth embodiment of the present invention. FIG. 9 is a schematic front view of a piezoelectric power generator according to a fifth embodiment of the present invention. FIG. 10 is a schematic front view of a piezoelectric power generator according to a sixth embodiment of the present invention. FIG. 11 is a perspective view for explaining a modification of the piezoelectric power generation plate constituting the piezoelectric power generation device of the present invention. FIG. 12 is a perspective view for explaining still another modification of the piezoelectric power generation plate constituting the piezoelectric power generation device of the present invention. FIG. 13 is a perspective view for explaining an example of a conventional piezoelectric power generation apparatus.

Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings.

FIG. 1 shows a piezoelectric generator 1 according to a first embodiment of the present invention. Fig.1 (a) is a typical front view of the piezoelectric electric power generating apparatus 1 which concerns on the 1st Embodiment of this invention, FIG.1 (c) is the perspective view.

The piezoelectric power generation device 1 has a first piezoelectric power generation plate 2 and a second piezoelectric power generation plate 7. The first piezoelectric power generation plate 2 has a structure in which a plate-like first piezoelectric element 3 is bonded to one side of a metal plate 4. That is, the first piezoelectric power generation plate 2 is a unimorph type piezoelectric diaphragm. Similarly, the second piezoelectric power generation plate 7 is also a unimorph type piezoelectric diaphragm having a structure in which the plate-like second piezoelectric element 5 is bonded to one side of the metal plate 6.

FIG. 1B is a schematic front view showing the polarization structure of the first piezoelectric element 3 constituting the piezoelectric power generating apparatus 1 according to the first embodiment of the present invention. Although not shown in FIG. 1A, the first piezoelectric element 3 includes a first piezoelectric ceramic plate 3a using piezoelectric ceramics as the material of the piezoelectric plate, as shown in FIG. 1B. It has a structure in which electrodes 3b and 3c are formed on both sides. The first piezoelectric ceramic plate 3a is polarized in the thickness direction. Specifically, as shown by the arrows in the figure, the first polarization region P1 that is the central region in the length direction of the first piezoelectric ceramic plate 3a and the outer side in the length direction of the first piezoelectric ceramic plate 3a. The second and third polarization regions P2 and P3, which are regions, are polarized in opposite directions in the thickness direction.

As will be described later, when the first piezoelectric element 3 is deformed in the buckling mode due to external vibration or external force, the stress generated in the first polarization region P1 and the second and third polarization regions P2, P3. The stress generated in is in the opposite direction in the thickness direction.

The plate-like second piezoelectric element 5 of the second piezoelectric power generation plate 7 also has the same structure as the first piezoelectric element 3. That is, the second piezoelectric element 5 has a structure in which electrodes are formed on both surfaces of a second piezoelectric ceramic plate using piezoelectric ceramics as a material of the piezoelectric plate. In the second piezoelectric ceramic plate, the central region in the length direction of the second piezoelectric ceramic plate and the outer region in the length direction of the second piezoelectric ceramic plate are polarized in opposite directions in the thickness direction. Yes. However, in the second piezoelectric element 5, the central region in the length direction of the second piezoelectric ceramic plate is polarized in the opposite direction to the first polarization region P1 of the first piezoelectric element 3, and the second piezoelectric element 5 The outer region in the length direction of the piezoelectric ceramic plate is polarized in the opposite direction to the second and third polarization regions P2 and P3 of the first piezoelectric element 3. As will be described later, this is because the second piezoelectric element 5 is deformed in the opposite direction to the first piezoelectric element 3 when an external vibration or external force is applied.

In addition, the piezoelectric ceramic plate in which electrodes are formed on both surfaces constituting the first and second piezoelectric elements 3 and 5 is made of a lead zirconate titanate ceramic in this embodiment. However, the piezoelectric ceramic plate can be made of an appropriate piezoelectric material such as a lead-free piezoelectric ceramic. Examples of the lead-free piezoelectric ceramic include alkali niobic ceramics such as potassium sodium niobate.

The electrodes constituting the first and second piezoelectric elements 3 and 5 are made of an appropriate metal such as Ag or Cu or an alloy of an appropriate metal.

The first piezoelectric element 3 is bonded to the metal plate 4 with an adhesive (not shown). As such an adhesive, a conductive adhesive or an insulating adhesive can be used. In addition, the electrode 3c of FIG.1 (b) is a part bonded by the metal plate 4, and when using the metal plate 4 as an electrode, the electrode 3c may be abbreviate | omitted. Similarly, the second piezoelectric element 5 is also bonded to the metal plate 6 with an adhesive (not shown).

The first and second piezoelectric power generation plates 2 and 7 have a rectangular plate shape, and are connected by the first and second connection members 8 and 9 so that the main surfaces face each other. The first and second connecting members 8 and 9 can be formed of an appropriate material such as insulating ceramics such as alumina, resin, or metal. In the present embodiment, the first and second connecting members 8 and 9 are connected to the first piezoelectric power generation plate 2 at both ends in the length direction of the first and second piezoelectric power generation plates 2 and 7 having a rectangular plate shape. The second piezoelectric power generation plate 7 is joined. This bonding can also be performed using a bonding agent such as an appropriate adhesive.

The first and second piezoelectric power generation plates 2 and 7 and the first and second connecting members 8 and 9 constitute one piezoelectric power generation element.

In this embodiment, the support member 10 is joined to the upper surface of the first piezoelectric power generation plate 2, that is, the surface opposite to the side to which the first and second connecting members 8 and 9 are joined. The support member 10 is fixed to the central portion in the length direction of the first piezoelectric power generation plate 2. The support member 10 can also be formed of an appropriate material such as ceramics or metal. The support member 10 is provided to fix and support the piezoelectric power generator 1 to the outside. The support member 10 may be fixed to other than the upper surface of the first piezoelectric power generation plate 2.

On the other hand, the mass adding member 12 is connected to the lower surface of the second piezoelectric power generation plate 7, that is, the surface opposite to the side where the first and second connecting members 8 and 9 are joined via the connecting member 11. It is fixed. The connecting member 11 can be made of an appropriate material such as ceramics, resin, or metal. The mass addition member 12 can be formed of an appropriate material that can add mass such as metal or ceramics. In order to add a large mass, the mass adding member 12 is preferably made of a material having a specific gravity larger than that of the piezoelectric ceramic plate, and is preferably made of a metal.

In addition, it points out that illustration of the said mass addition member 12 is abbreviate | omitted in FIG.1 (c).

The mass adding member 12 is provided to increase the amount of displacement in first and second piezoelectric power generation plates 2 and 7 which will be described later. But the mass addition member 12 does not necessarily need to be provided.

In the piezoelectric power generation device 1 of the present embodiment, the support member 10 is fixed to the outside. Therefore, in use, the portion where the support member 10 is fixed to the first piezoelectric power generation plate 2 becomes a fixed end, and the end opposite to the fixed end, that is, the side where the mass addition member 12 is provided. The end is a free end and is displaced by external force or vibration applied from the outside.

FIGS. 2A and 2B schematically show the displacement state of the first and second piezoelectric power generation plates 2 and 7 in the piezoelectric power generation apparatus 1 according to the first embodiment of the present invention. That is, when external vibration or external force is applied to the structure in which the first and second piezoelectric power generation plates 2 and 7 are connected by the first and second connecting members 8 and 9, the first and second piezoelectric power generation plates 2 and 7 are connected. The power generation plates 2 and 7 are displaced. This displacement is repeated between the state A shown in FIG. 2A and the state B shown in FIG. In this case, the first piezoelectric power generation plate 2 and the second piezoelectric power generation plate 7 are displaced in opposite phases.

On the other hand, since both the first and second piezoelectric power generation plates 2 and 7 are displaced when vibration or an external force is applied from the outside, in this embodiment, the electric charge generated by the displacement in the first piezoelectric power generation plate 2. And a large electric power can be taken out by the electric charge generated in the second piezoelectric power generation plate 7.

More specifically, for example, since the first piezoelectric ceramic plate 3a has the polarization structure as described above, a boundary where stress is reversed is generated between the central region in the length direction and the outer region. In addition, the polarization direction of the first polarization region P1 that is the central region and the polarization direction of the second and third polarization regions P2 and P3 that are the outer regions are also opposite to each other. Therefore, when the displacement shown in FIG. 2 occurs, the polarities of the charges generated on the surface of the plate-like first piezoelectric element 3 are the same. Therefore, even with an easy structure in which a common electrode is formed on the surface of the first piezoelectric element 3, it is possible to efficiently extract power. The same applies to the second piezoelectric power generation plate 7.

According to the piezoelectric power generation device 1 of the present embodiment, when tensile stress or compression stress is applied in the stacking direction of the first and second piezoelectric power generation plates 2 and 7 in the piezoelectric power generation element, the first and second piezoelectric power generations are performed. The first and second piezoelectric power generation plates 2 and 7 are displaced in the buckling mode so that the opposing distances in the central region of the plates 2 and 7 increase or decrease. At this time, the support member 10 or the connecting member 11 formed in the central region of the first and second piezoelectric power generation plates 2 and 7 is perpendicular to the main surface of the first and second piezoelectric power generation plates 2 and 7. If it arrange | positions on a straight line, the magnitude | size of the bending moment which acts on the 1st, 2nd piezoelectric power generation plates 2 and 7 in which the connection member 10 or the support member 11 was formed can be suppressed. That is, in the outer region of the first and second piezoelectric power generation plates 2 and 7 shown in FIG. The bending moment acting on the singular point is reduced. As a result, the sum of stresses is reduced, so that an effect of reducing cracks generated in the first and second piezoelectric power generation plates 2 and 7 can be obtained. When taking out the electric power, the electrode 3b of the first piezoelectric element 3 and the electrode on the connecting member 11 side of the second piezoelectric element 5 are commonly connected to serve as the first terminal. That is, the electrodes on the side where the connecting member 10 or the support member 11 is formed in the first piezoelectric element 3 and the second piezoelectric element 5 are commonly connected to serve as the first terminal. In addition, the electrode 3c of the first piezoelectric element 3 and the electrode bonded to the metal plate 6 of the second piezoelectric element 5 are commonly connected to serve as a second terminal. That is, the electrodes bonded to the metal plates 4 and 6 in the first piezoelectric element 3 and the second piezoelectric element 5 are commonly connected to serve as the second terminal. Electric power can be taken from the first terminal and the second terminal.

In the piezoelectric power generation device 1 of the present embodiment, as described above, the first piezoelectric power generation plate 2 and the second piezoelectric power generation plate 7 are arranged to face each other and are connected by the first and second connection members 8 and 9. Has a structure. Therefore, when vibration or external force is applied from the outside, electric power can be taken out from both the first piezoelectric power generation plate 2 and the second piezoelectric power generation plate 7. Therefore, large electric power can be taken out.

Moreover, as described below, the piezoelectric power generation device 1 can be easily manufactured without going through complicated steps.

First, for example, the first polarization region P1 and the second and third polarization regions P2 and P3 of the plate-like first piezoelectric element 3 can be easily formed. For example, the first polarization electrode is formed on the first polarization region P1 on one main surface of the first piezoelectric ceramic plate 3a, and the second and third polarizations are prevented from coming into contact with the first polarization electrode. The second and third polarization electrodes are formed on the regions P2 and P3, and the entire surface electrodes are formed on the first to third polarization regions P1 to P3 on the other main surface of the first piezoelectric ceramic plate 3a. Then, a DC voltage having one polarity is applied between the first polarization electrode and the entire surface electrode, and a DC current having a polarity opposite to the one polarity is applied between the other second and third polarization electrodes and the entire surface electrode. Apply voltage. Thereby, the polarization structure described above can be easily formed. Alternatively, after removing the first to third polarization electrodes, an electrode may be formed on the entire surface to form the electrode 3b. Alternatively, the electrode 3b may be formed by further forming a conductive film while leaving the first to third polarization electrodes. The full surface electrode may be the electrode 3c.

Second, the plate-like first piezoelectric element 3 is bonded to the metal plate 4 to form the first piezoelectric power generation plate 2, and the second piezoelectric element 5 is similarly bonded to the metal plate 6 to make the second The piezoelectric power generation plate 7 is configured, and the first piezoelectric power generation plate 2 and the second piezoelectric power generation plate 7 need only be connected by the first and second connection members 8 and 9. And the piezoelectric generator 1 can be obtained only by joining the supporting member 10 and the connection member 11 as needed, and connecting the mass addition member 12. FIG.

Since the piezoelectric power generation device described in Patent Document 2 described above uses a piezoelectric power generation plate that is folded back and forth in a zigzag manner, the piezoelectric power generation device can be greatly displaced by external vibration and external force, and can take out large electric power. However, it is necessary to form a complicatedly shaped piezoelectric power generation plate having a zigzag shape, and the polarization method is very complicated.

On the other hand, the piezoelectric power generation apparatus 1 of the present embodiment can be easily manufactured through the simple process as described above.

Further, since the first and second piezoelectric power generation plates 2 and 7 are stacked, the dimension in the surface direction of the first and second piezoelectric power generation plates 2 and 7 can be reduced. Thereby, the dimension of the surface direction of the piezoelectric generator 1 can be reduced. Therefore, it is possible to provide a small piezoelectric power generator 1 that can take out large electric power.

FIG. 3 is a schematic front view of the piezoelectric power generation device 21 according to the second embodiment of the present invention. The piezoelectric power generation device 21 includes first and second piezoelectric power generation plates 2 and 7 and a mass addition member 12, similarly to the piezoelectric power generation device 1 of the first embodiment. About the same part as 1st Embodiment, the same reference number is attached | subjected in FIG. 3, and it abbreviate | omits by using the description performed about 1st Embodiment.

The piezoelectric power generation device 21 of the second embodiment is different from the piezoelectric power generation device 1 of the first embodiment in that the first piezoelectric power generation plate 2 and the second piezoelectric power generation plate 7 are in the central portion in the length direction. The first and second support members 10A and 10B are connected to each other via one connecting member 22, and the upper surface of the first piezoelectric power generation plate 2, that is, the side to which the connecting member 22 is joined is supported. Are provided on the opposite surface, and the first and second connecting members 11A and 11B are connected to the lower surface of the second piezoelectric power generation plate 7, that is, the connecting member 22 is connected as a connecting member for connecting the mass adding member 12. It exists in the surface on the opposite side to the side currently made.

That is, the first and second support members 10 </ b> A and 10 </ b> B are fixed to both ends in the length direction of the first piezoelectric power generation plate 2. The first and second support members 10A and 10B are provided to fix and support the piezoelectric power generation device 21 to the outside. Therefore, the first and second support members 10A and 10B are fixed to the outside. Accordingly, the piezoelectric power generation device 21 of the present embodiment is fixed to the outside at the end of the upper surface of the first piezoelectric power generation plate 2. Therefore, the piezoelectric power generation device 21 can be more stably fixed to the outside.

FIGS. 4A and 4B schematically show the displacement states of the first and second piezoelectric power generation plates 2 and 7 in the piezoelectric power generation apparatus 21 according to the second embodiment of the present invention. Since the first and second piezoelectric power generation plates 2 and 7 are connected by a connecting member 22 provided in the center in the length direction, the first and second piezoelectric power generation plates 2 and 7 vibrate from the outside. When an external force is applied, the displacement is repeated between the state A shown in FIG. 4A and the state B shown in FIG.

The first and second connecting members 11 </ b> A and 11 </ b> B are located at both ends in the length direction of the second piezoelectric power generation plate 7. Therefore, the first and second piezoelectric power generation plates 2 and 7 are lined with respect to a virtual center line that passes through the center of both and extends in parallel with the main surface of the first and second piezoelectric power generation plates 2 and 7. Transform symmetrically. Accordingly, also in the present embodiment, the first and second piezoelectric power generation plates 2 and 7 are displaced in opposite phases when vibration or external force is applied from the outside. Therefore, since the first and second piezoelectric power generation plates 2 and 7 are configured in the same manner as in the first embodiment, the first and second piezoelectric power generation plates 2 and 7 also occur in this embodiment. Large electric power can be extracted from the accumulated electric charge.

In this embodiment, the mass adding member 12 is connected to the second piezoelectric power generation plate 7 by the first and second connecting members 11A and 11B.

Also in this embodiment, since the mass addition member 12 is connected, the amount of displacement can be further increased, and even larger electric power can be taken out.

Also in the second embodiment, large electric power can be taken out by utilizing the deformation of the first and second piezoelectric power generation plates 2 and 7. Also in the present embodiment, as in the first embodiment, the first and second piezoelectric power generation plates 2 and 7 can be easily manufactured, and the first and second piezoelectric power generation plates 2 and 2 can be easily manufactured. 7 and the mass adding member 12 and the first and second support members 10A and 10B can be easily joined. Therefore, the piezoelectric power generation device 21 of this embodiment can also be easily manufactured in the same manner as the piezoelectric power generation device 1 of the first embodiment.

FIGS. 5A and 5B are plan views of the first and second piezoelectric power generation plates 2 and 7 used in the piezoelectric power generation apparatus 31 according to the third embodiment of the present invention. FIG. 6 is a perspective view showing the appearance of the piezoelectric power generation apparatus 31 according to the third embodiment of the present invention.

The piezoelectric power generation apparatus 31 of the third embodiment is different from the first and second piezoelectric power generation plates 2 and 7 except that the first and second cutout portions 2a, 2b, 7a, and 7b are provided. Is the same as that of the piezoelectric power generation apparatus 1 of the first embodiment. Accordingly, the same parts are denoted by the same reference numerals, and the description thereof is omitted. In addition, illustration of the mass addition member 12 is abbreviate | omitted in FIG.

As shown in FIG. 5 (a), the first piezoelectric power generation plate 2 has a pair of long sides 2c, 2d and a pair of short sides 2e, 2f. The first cutout portion 2a extends from the long side 2c toward the opposite long side 2d, but does not reach the long side 2d. Similarly, the second notch 2b extends from the long side 2d toward the opposite long side 2c, but does not reach the long side 2c.

In the first piezoelectric power generation plate 2, a portion where the support member 10 is fixed, that is, a piezoelectric power generation plate portion between the fixed end and the short side 2e, and a piezoelectric power generation plate portion between the fixed end and the short side 2f, However, when viewed from the long side 2d side, it is displaced while maintaining a shape that is line symmetric with respect to the center line that passes through the center of the support member 10 and is orthogonal to the first piezoelectric power generation plate 2. Accordingly, the first notch 2a is provided at an equivalent position with respect to the center line, and the second notches 2b and 2b are also provided at an equivalent position with respect to the center line.

In addition, in the piezoelectric power generation plate portion between the portion where the support member 10 is fixed and the one short side 2f, the first notch portion 2a and the second notch portion 2b are the first piezoelectric power generation. The plates 2 are alternately arranged in the length direction. Similarly, in the piezoelectric power generation plate portion between the portion to which the support member 10 is fixed and the short side 2e, the first notch portions 2a and the first notches 2a are alternately arranged in the length direction of the first piezoelectric power generation plate 2. Two notches 2b are arranged. Although not shown, the first notch portion 2a and the second notch portion 2b are arranged so that the widths of the opposing long sides of the first and second piezoelectric power generation plates 2 and 7 become narrower toward the center. May be formed on the first and second piezoelectric power generation plates 2 and 7.

Therefore, since the first and second cutout portions 2a and 2b are provided on the first piezoelectric power generation plate 2, the piezoelectric elements on both sides of the first cutout portion 2a when external vibration or external force is applied. The piezoelectric power generation plate portions on both sides of the power generation plate portion and the second notch portion 2b are displaced in the opposite directions. In other words, when viewed from the long side 2d side, the first piezoelectric power generation plate 2 is displaced so as to form a meander shape. Therefore, if the polarization direction is reversed between the parts displaced in the opposite directions, the resonance frequency can be lowered in this embodiment as compared with the case of the first embodiment.

As shown in FIG. 5B, the second piezoelectric power generation plate 7 similarly has first and second cutout portions 7a and 7b. Specifically, the second piezoelectric power generation plate 7 has a pair of long sides 7c and 7d and a pair of short sides 7e and 7f. The first cutout portion 7a extends from the long side 7c toward the opposite long side 7d, but does not reach the long side 7d. Similarly, the second notch 7b extends from the long side 7d toward the opposite long side 2c, but does not reach the long side 7c. The formation positions of the first and second cutout portions 7a and 7b are the same as the formation positions of the first and second cutout portions 2a and 2b. That is, the first piezoelectric power generation plate 2 and the second piezoelectric power generation plate 7 have the same shape.

Therefore, in the piezoelectric power generation device 31 of the present embodiment, the first cutout portions 2a and 7a and the second cutout portions 2b and 7b are provided, so that a relatively low frequency vibration and a small external force are applied. Even in the case, a large amount of displacement can be obtained. Therefore, it is possible to take out a larger amount of electric power than in the first embodiment.

7A and 7B are plan views of the first and second piezoelectric power generation plates 2 and 7 used in the piezoelectric power generation device 41 according to the fourth embodiment of the present invention. FIG. 8 is a perspective view showing an appearance of a piezoelectric power generation apparatus 41 according to the fourth embodiment of the present invention. The piezoelectric power generation apparatus 41 according to the fourth embodiment is the same as the piezoelectric power generation according to the third embodiment except for the position where the second piezoelectric power generation plate 7 first and second cutout portions 7a and 7b are provided. This is the same as the device 31. In addition, in FIG. 8, illustration of the mass addition member 12 is abbreviate | omitted similarly to FIG. In the first piezoelectric power generation plate 2, of the first and second cutout portions 2 a and 2 b, the second cutout portion 2 b is a portion to which the support member 10 is fixed, at the center in the length direction. close. In contrast, in the second piezoelectric power generation plate 7, of the first and second cutout portions 7a and 7b, the first cutout portion 7a is close to the center in the length direction. In the first piezoelectric power generation plate 2, the first notch 2 a of the first and second notches 2 a and 2 b is close to the short sides 2 e and 2 f, whereas the second piezoelectric generator 2 In the plate 7, of the first and second cutout portions 7a and 7b, the second cutout portion 7b is close to the short sides 7e and 7f.

Thus, the formation positions of the first and second cutout portions 7a and 7b in the second piezoelectric power generation plate 7 are different from the formation positions of the cutout portions 2a and 2b in the first piezoelectric power generation plate 2. Also good.

Also in the present embodiment, the first and second notch portions 2a, 2b, 7a, and 7b are formed in the first and second piezoelectric power generation plates 2 and 7, as in the third embodiment. Therefore, the resonance frequency can be further lowered and a large electric power can be taken out. Further, in the piezoelectric power generation device 41 of the fourth embodiment, the positions of the first and second cutout portions 2a, 2b, 7a, 7b in the first piezoelectric power generation plate 2 and the second piezoelectric power generation plate 7 are as described above. It has been reversed. Therefore, the stacked structure of the first and second piezoelectric power generation plates 2 and 7 is easily twisted by external vibration and external force. Therefore, a large amount of displacement can be obtained by this deformation in the twist direction. Therefore, it is possible to take out a larger amount of power and lower the resonance frequency.

FIG. 9 is a schematic front view of a piezoelectric generator 51 according to a fifth embodiment of the present invention. The piezoelectric power generation device 51 according to the fifth embodiment corresponds to a modification of the piezoelectric power generation device 1 according to the first embodiment. The piezoelectric power generation device 51 according to the fifth embodiment differs from the piezoelectric power generation device 1 according to the first embodiment in that: 1) a first power generation plate 2 facing the first piezoelectric power generation plate 2 to which the support member 10 is fixed; 4 layers of structures in which the first and second piezoelectric power generation plates 2 and 7 are similarly stacked are connected to the lower surface of the second piezoelectric power generation plate 7 via a connecting member 11, and 2) The mass adding member 12 is connected to the lower surface of the second piezoelectric power generation plate 7 located in the lowermost layer via the connecting member 11. Therefore, a power generation structure in which a plurality of piezoelectric power generation elements having the first and second piezoelectric power generation plates 2 and 7 are stacked between the support member 10 serving as a fixed end and the mass addition member 12 is as illustrated. Are connected in series via a connecting member 11 arranged on a line connecting a supporting member 10 serving as a fixed end and a connecting member 11 to which the mass load member 12 is connected. At this time, the value of the bending moment given to the piezoelectric power generating element by the connecting portion 11 that connects the plurality of piezoelectric power generating elements is suppressed. Therefore, even when a plurality of piezoelectric power generation plates are stacked and connected in series, the stress acting on the connection portion of the piezoelectric power generation plates can be reduced. Therefore, when vibration or external force is applied from the outside, in this embodiment, power can be taken out from each of the five piezoelectric power generation elements, so that even larger power can be taken out.

Thus, in the present invention, a plurality of piezoelectric power generation elements may be connected in series. FIG. 9 shows an embodiment in which the length of the piezoelectric power generation plate in the long side direction is the same. However, the length of the piezoelectric power generation element in the long side direction may be changed in the stacking direction. You may change the angle which overlaps.

FIG. 10 is a schematic front view of a piezoelectric power generator 61 according to a sixth embodiment of the present invention. The piezoelectric power generation device 61 of the sixth embodiment corresponds to a modification of the piezoelectric power generation device 21 of the second embodiment. Similarly to the piezoelectric power generation device 51 of the fifth embodiment, the piezoelectric power generation device 61 of the present embodiment also has a power generation structure in which a plurality of piezoelectric power generation elements having first and second piezoelectric power generation plates 2 and 7 are stacked. Are connected in series. As shown in FIG. 10, the power generation structure in which a plurality of piezoelectric power generation elements having first and second piezoelectric power generation plates 2 and 7 are stacked is a first piezoelectric element in which support members 10A and 10B serving as fixed ends are fixed. Fixed to the central portion of the second piezoelectric power generation plate 7 to which the connecting member 22 fixed to the central portion of the power generating plate 2 and the first and second connecting portions 11A and 11B to which the mass adding member 12 is connected are fixed. The first and second support members 10A and 10B, which are fixed ends, and the mass adding member 12 are connected in series via a connecting member 22 arranged on a line connecting the connecting member 22 formed. .

Like the piezoelectric power generation device 61 of the sixth embodiment, a plurality of power generation structures including the first and second piezoelectric power generation plates 2 and 7 are connected in series even in a structure corresponding to the piezoelectric power generation device 21 of the second embodiment. You may connect to. Thereby, large electric power can be taken out.

In the first to sixth embodiments described above, the first and second piezoelectric power generation plates have a rectangular plate shape having a length direction. However, in the present invention, the piezoelectric power generation plate has a length. The structure is not limited to a rectangular plate structure having a direction. For example, as in the modification shown in FIG. 11, the spiral-type piezoelectric power generation plate 71 may be formed by forming a notch 71a in a rectangular piezoelectric plate. The piezoelectric power generation plate 71 may be used as the first and second piezoelectric power generation plates. In this case, the central portion of the piezoelectric power generation plate 71 is used as a fixed end formed by joining the support member, and a connecting member that connects a pair of corner portions facing each other across the central portion to another piezoelectric power generation plate is joined. What is necessary is just to use as a part. Alternatively, a pair of opposing corners may be used as fixed ends to which the support member is joined, and the central part of the piezoelectric power generation plate may be used as a connection part that connects to another piezoelectric power generation plate.

When such a piezoelectric power generation plate 71 is used, when a vibration or external force is applied from the outside, it is deformed more with the fixed end as a fulcrum, so that a larger electric power can be taken out.

Alternatively, a piezoelectric power generation plate 81 that deforms into a biaxial meander type as shown in a perspective view in FIG. 12 may be used. In the piezoelectric power generation plate 81, small square openings 81a to 81d are provided in the vicinity of the four corner portions. Taking adjacent openings, for example, the opening 81a and the opening 81b, as an example, a notch 81e extending from the opening 81a toward the opening 81b, and extending from the opening 81b toward the 81a side. A notch 81f is formed. Therefore, when the central portion is a fixed end and a pair of opposing corner portions is a connecting portion, the central portion is deformed as a fulcrum. At this time, the piezoelectric power generation plate portion between the fixed end of the central portion and the side 81g where the openings 81a and 81b are provided is deformed in a meander shape. Similarly, the center fixed portion and the piezoelectric power generation plate portion on the side 81h side facing the side 81g are similarly deformed in a meander shape. On the other hand, in the direction connecting the other opposing sides 81i and 81j, it deforms in a meander shape in the direction orthogonal to the direction connecting the sides 81g and 81h. That is, a biaxial meandering deformation occurs. At this time, if a meander-shaped notch portion is arranged in a rotationally symmetric position in the piezoelectric power generation plate 81 with the center as an axis, the meandering torsional deformation is canceled out by the 180-degree rotation portion, and the piezoelectric power generation The rotation of the plate 81 and the inclination of the main surface are suppressed, and the vibration of the piezoelectric power generation plate 81 is stabilized. For this reason, fluctuations in the power generation amount of the piezoelectric power generation plate 81 can be reduced.

As described above, in the piezoelectric generator plate 81 having a square shape, the piezoelectric generator plate 81 is deformed into a meander shape in both the direction connecting a pair of opposing sides and the direction connecting another pair of opposing sides. It may be configured. Also in this case, similarly to the case where the piezoelectric power generation plate 71 is used, by using the piezoelectric power generation plate 81 as the first and second piezoelectric power generation plates, the resonance frequency can be lowered and a large displacement amount can be obtained. Can be obtained. Therefore, even when a low frequency vibration or a small external force is applied, a large electric power can be taken out.

In the first to sixth embodiments, the piezoelectric power generation plate having a unimorph structure in which the piezoelectric element is bonded to the metal plate is shown. However, in the present invention, the piezoelectric power generation plate has the piezoelectric elements bonded to both surfaces of the metal plate. Alternatively, a piezoelectric power generation plate having a bimorph structure or a multi-morph structure piezoelectric power generation plate including a plurality of piezoelectric elements may be used. However, by adopting a unimorph structure in which a piezoelectric element is bonded to one side of a metal plate, the rigidity of the piezoelectric power generation plate is lowered and the resonance frequency is lowered compared to a bimorph structure in which a piezoelectric element is bonded to both sides of a metal plate. can do. Therefore, it is desirable that the piezoelectric power generation plate is composed of the unimorph type piezoelectric vibrator as described above in terms of enhancing the piezoelectric efficiency even with low frequency vibration.

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric generator 2 ... 1st piezoelectric power generation board 2a, 2b ... 1st, 2nd notch part 2c, 2d ... Long side 2e, 2f ... Short side 3 ... 1st piezoelectric element 3a ... 1st Piezoelectric ceramic plates 3b, 3c ... electrodes 4 ... metal plates 5 ... second piezoelectric elements 6 ... metal plates 7 ... second piezoelectric power generation plates 7a, 7b ... first and second notches 7c, 7d ... long sides 7e, 7f ... short side 8, 9 ... first and second connecting members 10 ... supporting members 10A, 10B ... first and second supporting members 11 ... connecting members 11A, 11B ... first and second connecting members DESCRIPTION OF SYMBOLS 12 ... Mass addition member 21 ... Piezoelectric generator 22 ... Connecting member 31 ... Piezoelectric generator 41 ... Piezoelectric generator 51 ... Piezoelectric generator 61 ... Piezoelectric generator 71 ... Piezoelectric generator plate 71a ... Notch part 81 ... Piezoelectric generator plate 81a ... 81d ... Openings 81e, 81f ... Notches 81g to 81j ...

Claims (15)

A first piezoelectric power generation plate, a second piezoelectric power generation plate disposed so that the principal surfaces of the first piezoelectric power generation plate face each other, and the first and second piezoelectric power generation plates are coupled to each other. A piezoelectric power generation element having a connecting member,
A piezoelectric power generation device comprising: a support member fixed to the first piezoelectric power generation plate and fixing the piezoelectric power generation element to the outside. A plurality of the piezoelectric power generation elements are connected, and two piezoelectric power generation elements connected to each other are opposed to the first piezoelectric power generation plate of the second piezoelectric power generation plate of one of the piezoelectric power generation elements. The piezoelectric power generating device according to claim 1, wherein another piezoelectric power generating element is connected to a main surface opposite to the main surface. In the structure in which the plurality of piezoelectric power generation elements are connected, the support member is connected to a central portion or both ends of the first piezoelectric power generation plate, and the connection member is connected to the first and second piezoelectric power generation plates. The piezoelectric power generation device according to claim 2, wherein the piezoelectric power generation device is connected to the first and second piezoelectric power generation plates at a central portion or both end portions. 4. The piezoelectric power generation device according to claim 1, wherein the first and second piezoelectric power generation plates have a rectangular shape having a length direction. The connecting member connects the first piezoelectric power generation plate and the second piezoelectric power generation plate at positions of both ends of the main surface where the first piezoelectric power generation plate and the second piezoelectric power generation plate face each other. Including a first connecting member,
The said supporting member is provided in the center part of the main surface of a said 1st piezoelectric power generation board in the main surface on the opposite side to the side in which the said 1st, 2nd connection member is provided. The piezoelectric power generation device described in 1. The connecting member connects the first and second piezoelectric power generation plates at a central portion in the length direction of the first and second piezoelectric power generation plates,
The support member is provided with first and second support members at both ends in a length direction of a main surface opposite to a side where the connection member of the first piezoelectric power generation plate is provided. Item 5. The piezoelectric power generation device according to Item 4. 5. The piezoelectric power generation according to claim 4, wherein the first and second piezoelectric power generation plates are formed with notches extending from one long side to the other long side of the rectangular piezoelectric power generation plate. apparatus. The plurality of notches are provided, and the plurality of notches are provided on two long sides that alternately oppose in the length direction of the first and second piezoelectric power generation plates. 7. The piezoelectric power generation device according to 7. A pair of opposing corners of the rectangular first and second piezoelectric power generation plates are connected to each other by the connection member, and the support member is at the center of the first piezoelectric power generation plate. The piezoelectric power generation device according to claim 4, which is fixed. The first and second piezoelectric power generation plates are formed with notches extending from the inside of the piezoelectric power generation plate to the outer periphery between the portions where the first and second connecting members are provided. The piezoelectric power generation device according to claim 9. The piezoelectric power generation device according to claim 10, wherein a plurality of the cutout portions are provided, and the plurality of cutout portions are provided point-symmetrically with respect to a portion to which the support member is fixed. The mass adding member which is arranged at the principal surface side opposite to the side provided with the connection member of the second piezoelectric power generation plate, and is fixed to the second piezoelectric power generation plate. Item 12. The piezoelectric power generation device according to any one of Items 1, 4 to 11. The at least one piezoelectric power generation element is connected to a surface of the second piezoelectric power generation plate opposite to the first piezoelectric power generation plate via a connection member. The piezoelectric power generation device according to item. The first and second piezoelectric power generation plates have a first polarization region polarized in the thickness direction and a second polarization region polarized in the direction opposite to the first polarization region in the thickness direction. The piezoelectric power generation device according to any one of claims 1 to 13, further comprising a piezoelectric plate. The piezoelectric power generation device according to claim 14, wherein the piezoelectric power generation plate further includes a metal plate laminated on the piezoelectric plate, and a unimorph type piezoelectric element is configured.

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