JP2014033478A - Piezoelectric generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric generator which enables easy manufacturing and extracts large electric power.SOLUTION: In a piezoelectric generator 1, a second piezoelectric power generation plate 7 is disposed so as to face a first piezoelectric power generation plate 2, and the first and second piezoelectric power generation plates 2, 7 are connected by connection members 8, 9. A support member 10 for fixing the first piezoelectric power generation plate 2 to the exterior is provided at the first piezoelectric power generation plate 2.

Description

  The present invention relates to a piezoelectric power generation apparatus that can take out electric power when vibration is applied from the inside using a piezoelectric effect, and more specifically, has a structure in which a plurality of piezoelectric power generation plates are connected. The present invention relates to a piezoelectric power generation device.

  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 includes 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 portion 1002a opposite to the fixing member 1004. And the 2nd arm part 1002c is continued through the bent intermediate part 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 an external force is applied, the free end is greatly displaced, and a relatively large electric power can be generated. Has been.

  Further, Patent Document 2 below discloses a piezoelectric power generation device using a piezoelectric power generation plate bent a plurality of times in a zigzag manner. Also here, it is said that a large electric power can be generated when an external force is applied by using a piezoelectric power generation plate processed into a zigzag shape.

Special table 2010-517285 JP 2005-507627 A

  By the way, depending on the field of use of the piezoelectric power generator, the vibration applied to the piezoelectric power generator may be at 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 plate-like piezoelectric power generation element is used, a method of reducing the thickness is used in order to reduce the resonance frequency. However, the thickness of the plate-shaped piezoelectric power generation plate is obtained 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. If the thickness of the piezoelectric power generation plate is reduced, the strength of the folded portion is reduced, and plastic deformation and brittle fracture occur. Therefore, it is difficult to reduce the thickness of the piezoelectric power generation plate. Moreover, in the piezoelectric power generation device 1001 described in Patent Document 1, the piezoelectric element 1010 is attached to only a part of the metal plate 1002. Therefore, since the ratio of the piezoelectric elements 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 vibration at a low frequency is applied, and a method for manufacturing the same.

  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 elements connected to each other, the second piezoelectric power generation plate of one of the piezoelectric power generation elements. The other piezoelectric power generating element is connected to the main surface 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 the center or both ends of the first piezoelectric power generation plate, A 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 to connect the first and second piezoelectric power generating plates at the positions of both ends of the main surface facing each other. The supporting member is provided at the center of the main surface of the first piezoelectric power generation plate on the main surface opposite to the side on which the first and second connecting members are provided. ing. 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 alternately provided on opposite long sides in the length direction of the first and second piezoelectric power generation plates. In this case, when an external force is applied, 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 an 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 adding member is provided, the displacement amount of the first and second piezoelectric power generation plates when an external force is applied 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, the displacement amount of the piezoelectric power generation plate when an external force is applied can be increased. 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, when an external force is applied in a state of being fixed to the outside by the support member, Both the first and second piezoelectric power generation plates are displaced, and a 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, large electric 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.

BRIEF DESCRIPTION OF THE DRAWINGS (a)-(c) is a front view of the piezoelectric power generator concerning the 1st Embodiment of this invention, the typical front view which shows the polarization structure of a piezoelectric power generation board, and the perspective view which shows typically the whole structure. . It is a typical front view for demonstrating the displacement state of the 1st, 2nd piezoelectric power generation board in the piezoelectric power generator of 1st Embodiment. It is a typical front view of the piezoelectric power generator concerning the invention of the present invention. It is a typical front view for demonstrating the displacement state of the piezoelectric power generator of 2nd Embodiment. (A) And (b) is each top view for demonstrating the modification of the piezoelectric power generator of 2nd Embodiment. It is a perspective view for demonstrating the piezoelectric generator of the 3rd Embodiment of this invention. (A) And (b) is each top view for demonstrating the 1st, 2nd piezoelectric power generation board used for the piezoelectric power generation apparatus which concerns on the 4th Embodiment of this invention. It is a perspective view of the piezoelectric electric power generating apparatus which concerns on the 4th Embodiment of this invention. It is a front view of the piezoelectric electric power generating apparatus which concerns on the 5th Embodiment of this invention. It is a front view of the piezoelectric electric power generating apparatus which concerns on the 6th Embodiment of this invention. It is a perspective view for demonstrating the modification of the piezoelectric power generator of this invention. It is a perspective view for demonstrating the further another modification of the piezoelectric electric power generating apparatus of this invention. It is a perspective view for demonstrating an example of the conventional piezoelectric generator.

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

  Fig.1 (a) is a front view of the piezoelectric power generator concerning the 1st Embodiment of this invention, FIG.1 (c) is the perspective view.

  The piezoelectric power generation apparatus 1 includes 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 first plate-like 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 vibration plate in which a plate-like piezoelectric element 5 is bonded to one side of a metal plate 6.

  Although not shown in FIG. 1A, as shown in FIG. 1B, the piezoelectric element 3 has electrodes 3b and 3c on both surfaces of a piezoelectric ceramic plate 3a using piezoelectric ceramic as a material for the piezoelectric plate. Has a structure formed. The piezoelectric ceramic plate 3a is polarized in the thickness direction. However, as shown by the arrows in the figure, the polarization region P1 at the center of the piezoelectric ceramic plate 3a and the polarization regions P2 and P3 on both sides are polarized in opposite directions in the thickness direction.

  As described later, when the piezoelectric element 3 is deformed in the buckling mode by applying an external force, the stress generated in the polarization region P1 and the stress generated in the polarization regions P2 and P3 are opposite in the thickness direction.

  The plate-like piezoelectric element 5 of the second piezoelectric power generation plate 7 has the same structure as the piezoelectric element 3. However, in the second piezoelectric element 5, the central region in the length direction is polarized in the opposite direction to the first polarization region P 1 of the piezoelectric element 3, and the regions on both sides are the second and second regions of the piezoelectric element 3. Polarization processing is performed in the opposite direction to the three polarization regions P2 and P3. This is because the piezoelectric element 5 is deformed in the opposite direction to the piezoelectric element 3 when an external force is applied, as will be described later.

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

  The electrodes 3b and 3c are made of an appropriate metal such as Ag or Cu.

  The 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.

  The first and second piezoelectric power generation plates 2 and 7 have a rectangular plate shape, and are connected by first and second connecting members 8 and 9 so that their main surfaces face each other. The 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 provided at the both ends in the length direction of the rectangular plate-shaped piezoelectric power generation plates 2 and 7, and the first piezoelectric power generation plate 2 and the second piezoelectric power generation plate 7. And are 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 at the center of the piezoelectric power generation plate 2 in the length direction. 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 fixed 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. Has been. 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 give a large mass, the mass adding member 12 is preferably made of a material having a specific gravity larger than that of the piezoelectric plate, and is preferably made of 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 the first and second piezoelectric power generation plates 2 and 7 described later, but the mass adding member 12 may not 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 portion is displaced by an external force or vibration applied as a free end.

  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 piezoelectric power generation plates 2 and 7 Displace. This displacement is repeated between the state shown by the solid line A and the state shown by the broken line B 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 an external force is applied, in this embodiment, the electric charge generated by the displacement in the piezoelectric power generation plate 2 and the piezoelectric power generation plate 7 Large electric power can be extracted by the generated electric charge.

  More specifically, for example, since the first piezoelectric ceramic plate 3a has the polarization structure as described above, a boundary where the stress is reversed is generated between the central region in the length direction and the end regions on both sides thereof. However, the polarization direction is also reversed between the central region and the second and third polarization regions P2 and P3 in the end region. Therefore, when a displacement as shown in FIG. 2 occurs, the polarity of electric charges generated on the surface of the plate-like piezoelectric element 3 becomes the same, and an easy structure in which a common electrode is formed on the surface of the piezoelectric element 3 Even so, it is possible to efficiently extract power. The same applies to the second piezoelectric power generation plate 7.

  According to an embodiment of the present invention, when a tensile force or a compressive force is applied in the stacking direction of the piezoelectric power generation elements, the piezoelectric power generation plates are displaced in a buckling mode so that the opposing distances of the piezoelectric power generation plates are increased or approached. Be made. At this time, if the support member or the connection member formed in the central region of the piezoelectric power generation plate is arranged on a straight line perpendicular to the main surface, the bending acting on the piezoelectric power generation plate on which the connection member or the support member is formed is provided. The magnitude of the moment can be suppressed. Therefore, in the end region of the piezoelectric power generation plate shown in FIG. 2, the bending moment acting on a single point in the central portion of the piezoelectric power generation plate that is supported at a plurality of points and cannot disperse stress is reduced, and the total sum of stress is reduced. This has the effect of reducing cracks generated in the piezoelectric power generation plate. When taking out the electric power, one electrode 3b of the first piezoelectric element 3 and an electrode located on the same outer surface of the second piezoelectric element 5 are connected in common to serve as a first terminal. Further, the electrodes located on the metal plates 4 and 6 side of the first and second piezoelectric power generation plates 2 and 7 are connected in common to serve as a 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 an external force is applied, electric power can be taken out from both the first piezoelectric power generation plate 2 and the second piezoelectric power generation plate 7, so that a 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 piezoelectric element 3 can be easily formed. For example, a first polarization electrode is formed on the first polarization region P1 on one main surface of the piezoelectric ceramic plate 3a and is not in contact with the first polarization electrode. Second and third polarization electrodes are formed on P3, and a full-surface electrode is formed on the opposite main surface. Then, a DC voltage is applied between the first polarization electrode and the entire surface electrode, and a reverse polarity DC voltage is applied between the second and third polarization electrodes and the entire surface electrode. Thereby, the polarization structure described above can be easily formed. In addition, after removing the 1st-3rd polarization electrode, an electrode may be formed in the whole surface and it may be set as the electrode 3b. Alternatively, the electrode 3b may be formed by further forming a conductive film while leaving the first to third polarization electrodes.

  Secondly, it is only necessary to attach the plate-like piezoelectric element 3 to the metal plate 4 and to connect the piezoelectric power generation plate 7 and the first and second connecting members 8 and 9 configured in the same manner. 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 uses a zigzag-shaped piezoelectric element, it can be largely displaced by an external force and take out large electric power. However, it is necessary to form a complicatedly shaped piezoelectric element having a zigzag shape, and the polarization method is very complicated.

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

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

  FIG. 3 is a front view of the piezoelectric power generation apparatus 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 as in the first embodiment. About the same part as 1st Embodiment, it abbreviate | omits by using the description performed about 1st Embodiment by attaching | subjecting the same reference number in FIG.

  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 one in the center in the length direction. That is, the first and second support members 10 </ b> A and 10 </ b> B are provided on the outer main surface of the first piezoelectric power generation plate 2 as support members.

  That is, the first and second support members 10 </ b> A and 10 </ b> B are provided at both ends in the length direction of the first piezoelectric power generation plate 2. Therefore, the piezoelectric power generation device 1 of the present embodiment is fixed to the outside at the upper end of the piezoelectric power generation plate 2. Therefore, the piezoelectric power generation device 21 can be more stably fixed to the outside.

  On the other hand, 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, an external force is applied to the first and second piezoelectric power generation plates 2 and 7. When added, it is displaced as shown by the solid line A1 and the broken line B1 in FIG.

  That is, 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 deformed symmetrically with respect to the center line of the lower layer that passes through the center of both and extends in parallel with the main surface of the first and second piezoelectric power generation plates. To do. Accordingly, also in the present embodiment, the first and second piezoelectric power generation plates 2 and 7 are displaced in opposite phases when an external force is applied. 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.

  Also 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 a larger amount of 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 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, the mass adding member 12, and the supporting member 10 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 first and second piezoelectric power generation boards used in the piezoelectric power generation apparatus according to the third embodiment of the present invention. FIG. 6 is a perspective view showing an appearance of the piezoelectric power generation apparatus according to the third embodiment.

  The piezoelectric power generation apparatus 31 according to the third embodiment is the same as the piezoelectric power generation according to the first embodiment except that the notches 2a and 2b are provided in the first and second piezoelectric power generation plates 2 and 7. It is the same as the device 1. Accordingly, the same parts are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 5A, the first piezoelectric power generation plate 2 has a pair of long sides 2c and 2d and a pair of short sides 2e and 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, the support member 10, that is, the piezoelectric power generation plate portion between the fixed end and the short side 2e and the piezoelectric power generation plate portion between the fixed end and the short side 2f are from the long side 2d side. When viewed, the center of the support member 10 is displaced while maintaining a shape that is line-symmetric with respect to the center line that is orthogonal to the piezoelectric power generation plate 2. Therefore, 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.

  Further, in the piezoelectric power generation plate portion between the support member 10 and one short side 2 f, the first notch portion 2 a and the second notch portion 2 b are alternately arranged in the length direction of the piezoelectric power generation plate 2. Has been placed. Similarly, in the piezoelectric power generation plate portion between the support member 10 and the short side 2e, the first cutout portion 2a and the second cutout portion 2b are alternately positioned in the length direction of the piezoelectric power generation plate 2. Has been. 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 notches 2a and 2b are provided, when an external force is applied, the piezoelectric power generation plate portions on both sides of the notch portion 2a and the piezoelectric power generation plate portions on both sides of the notch portion 2b are displaced in the reverse direction. It will be. In other words, when viewed from the long side 2d side, the 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.

  Similarly, the second piezoelectric power generation plate 7 has first and second cutout portions 7a and 7b.

  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.

  FIGS. 7A and 7B are plan views of first and second piezoelectric power generation plate portions of the piezoelectric power generation apparatus according to the fourth embodiment, and FIG. 8 is a perspective view showing an appearance thereof. In the first piezoelectric power generation plate 2, the side closer to the support member 10 is the second notch portion 2b, whereas in the piezoelectric power generation plate 7, the long side 7d extends from the long side 7c toward the long side 7d. The first notches 7c, 7c that do not reach the center are located on the center side. On the other hand, in the piezoelectric power generation plate 2, the first notches 2a and 2a are positioned on the short sides 2e and 2f, whereas in the piezoelectric power generation plate 7, the first notches 2a and 2f are positioned on the short sides 7e and 7f. The second notch 7b, 7b is located.

  As described above, the formation position of the notch portion in the second piezoelectric power generation plate 7 may be different from the formation position of the notch portions 2 a and 2 b in the first piezoelectric power generation plate 2.

  In the present embodiment as well, the first and second cutout portions 2a, 2b, 7a, and 7b are formed in the first and second piezoelectric power generation plates 2 and 7 as in the second embodiment. The resonance frequency can be further lowered and a large amount of electric power can be taken out. Further, in the piezoelectric power generation device 31 of the fourth embodiment, since the positions of the notches are inverted between the first piezoelectric power generation plate 2 and the second piezoelectric power generation plate 7 as described above, The stacked structure of the two piezoelectric power generation plates 2 and 7 is easily twisted by an 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 front view of a piezoelectric power generator 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 difference is that 1) a structure in which the first and second piezoelectric power generation plates 2 and 7 are similarly stacked on the lower surface of the second piezoelectric power generation plate 7 via a connecting member 11 is connected in four layers. 2) The mass adding member 12 is connected to the lower surface of the second piezoelectric power generation plate 7 having the stacked structure in the lowermost layer via the connecting member 11. Therefore, 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 between a support member 10 serving as a fixed end and a mass addition member 12 as shown in the drawing. They are connected in series via a connecting member 11 arranged on a line connecting the supporting member 10 serving as a fixed end and the connecting member 11 to which the mass load member 12 is connected. At this time, since 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, the piezoelectric power generation can be achieved even when the plurality of piezoelectric power generating plates are stacked and connected in series. The stress acting on the connecting portion of the plates can be reduced.

  Therefore, when an external force is applied, in the present 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 front view of a piezoelectric power generator according to a sixth embodiment of the present invention. The piezoelectric power generation device 61 corresponds to a modification of the piezoelectric power generation device 21 shown in FIG. The present embodiment also has a structure in which individual piezoelectric power generation elements are stacked and connected in series, similarly to the piezoelectric power generation apparatus 51. As shown in FIG. 10, the uppermost connecting portion 22 arranged in the intermediate portion between the supporting members 10A and 10B serving as the fixed ends and the intermediate portion between the connecting portions 11A and 11B to which the mass load member 12 is connected. The piezoelectric power generation elements are connected via a connecting member 22 arranged on a line connecting the lowermost connecting member 22.

  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. 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 a fixed end formed by bonding to the support member, and a connecting member that connects a pair of corner portions facing each other across the central portion to the other piezoelectric power generation plate is bonded. What is necessary is just to use as a part. Alternatively, a pair of opposite corners may be fixed ends to which the support member is bonded, and the central portion of the piezoelectric power generation plate may be used as a connection portion that is connected to another piezoelectric power generation plate.

  When such a piezoelectric power generation plate 71 is used, when an external force is applied, 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 is deformed into a biaxial meander type 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 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 center is a fixed end and a pair of opposing corners is a connecting part, the center is deformed as a fulcrum, but the center fixed end and the side 81g where the openings 81a and 81b are provided. The piezoelectric power generation plate portion in between 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 the unimorph structure in which the piezoelectric element is bonded to the metal plate is shown. However, the piezoelectric power generation plate may be configured by a plate-like bimorph type piezoelectric element. However, by adopting a unimorph structure in which a piezoelectric element is bonded to one side of the 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 the piezoelectric element is bonded to both sides of the 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 ... support member 11 ... connecting members 11A, 11B ... first and second connecting members 12 ... mass adding member 21 ... piezoelectric generator 22 ... Connecting member 31 ... piezoelectric generator 51 ... piezoelectric generator 61 ... piezoelectric generator 71 ... piezoelectric generator 71a ... notch 81 ... piezoelectric generator 81a-81d ... openings 81e, 81f ... notches 81g-81j ... side

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 apparatus 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 in the two piezoelectric elements connected to each other, the first piezoelectric power generation plate of the second piezoelectric power generation plate of one piezoelectric power generation element faces each other. 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 the center or both ends of the first piezoelectric power generation plate, and the connection member is connected to the center of the first and second piezoelectric power generation plates or The piezoelectric power generation device according to claim 2, wherein both ends of the piezoelectric power generation device are connected to the first and second piezoelectric power generation plates.   The piezoelectric power generation device according to any one of claims 1 to 3, wherein the first and second piezoelectric power generation plates have a rectangular shape having a length direction. The connecting member includes first and second connecting members that connect the first and second piezoelectric power generation plates at positions of both ends of the main surfaces facing each other.
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.   A plurality of the notches are provided, and the plurality of notches are alternately provided on opposite long sides in the length direction of the first and second piezoelectric power generation plates. The piezoelectric power generation device described.   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 and 4 to 11.   The at least one piezoelectric generating element is connected to the surface of the second piezoelectric generating plate opposite to the first piezoelectric generating plate via a connecting 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 claim 1, 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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