JP2011152004A - Power generation unit and power generation devic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power generation unit enabling stable power generation efficiently by using a piezoelectric element. <P>SOLUTION: The power generation unit at least includes: a housing (C); a first vibration piezoelectric body (B1) comprising a first vibration plate (P1) which is arranged and installed in this housing and vibrates in accordance with input into the housing and a first piezoelectric element (E1) which is joined to the first vibration plate and outputs voltage in conformity with displacement of the first vibration plate; and a second vibration piezoelectric body (B2) comprising a second vibration plate (P2) which is same as the first vibration plate (P1) and a second piezoelectric element (E1) which is joined to the second vibration plate and outputs the voltage in conformity with the displacement of the second vibration plate, and resonating at a frequency different from that of the first vibration piezoelectric body. Each vibration piezoelectric body resonates at the frequency different from each other, thereby enabling efficient power generation to be stably performed with respect to an input frequency having a wide range. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power generation unit capable of efficiently converting mechanical energy such as vibration energy into electric energy and a power generation apparatus using the power generation unit.

Along with the heightened environmental awareness, energy saving and the creation of energy with low environmental impact are required. As one of them, power generation using a piezoelectric element has attracted attention. Piezoelectric elements include PZT (lead zirconate titanate: Pb (Zr, Ti) O ₃ ) and the like, and when a pressure is applied in a specific direction, electric polarization is induced to generate a voltage. If this piezoelectric element is used, the mechanical displacement is converted into a voltage, so that power generation is possible. However, in order to extract available power, it is necessary to apply continuous displacement to the piezoelectric element. In view of this, a power generation unit capable of generating power by attaching a piezoelectric element to a diaphragm and applying a continuous displacement to the piezoelectric element using the amplitude of the diaphragm has been proposed in the following patent documents.

JP 7-49388 A JP 2006-166694 A

The above-described patent document describes that the output can be increased by resonating the diaphragm and the piezoelectric element. However, there is no mention of a specific measure suitable for actual use that can stably generate efficient power.
Note that FIG. 6 of Patent Document 2 describes a sound power generation apparatus in which a plurality of vibrating piezoelectric bodies each having a diaphragm and a piezoelectric element joined are arranged in a casing. However, the power generation device simply has a plurality of vibrating piezoelectric bodies having the same specifications arranged in parallel in order to increase the output voltage.

  The present invention has been made in view of such circumstances. That is, an object of the present invention is to provide a power generation unit capable of stably performing efficient power generation using a piezoelectric element, and a power generation apparatus using the power generation unit.

  The present inventor has intensively studied to solve this problem, and as a result of repeated trial and error, it is a vibrating piezoelectric body in which a diaphragm and a piezoelectric element are joined, and resonates at different frequencies, or inputs in different directions. I came up with a new idea of arranging a plurality of resonating elements in the housing. By developing this idea, the present invention described below has been completed.

《Power generation unit》
(1) A power generation unit according to the present invention includes a casing, a first diaphragm that is disposed in the casing and vibrates in response to an input to the casing, and is joined to the first diaphragm. A first vibration piezoelectric body including a first piezoelectric element that outputs a voltage corresponding to the displacement of the first vibration element, a second diaphragm that is disposed in the casing and vibrates in response to an input to the casing, and the second vibration A second piezoelectric element which is joined to a plate and outputs a voltage corresponding to the displacement of the second diaphragm, and which resonates at a frequency different from that of the first vibrating piezoelectric element. It generates electricity according to the input to the body.

(2) The power generation unit of the present invention includes a casing, a first diaphragm that is disposed in the casing and vibrates in response to an input to the casing, and is joined to the first diaphragm and the first vibration A first vibrating piezoelectric body including a first piezoelectric element that outputs a voltage corresponding to the displacement of the plate; a second vibrating plate disposed in the casing and vibrating in response to an input to the casing; and the second A second piezoelectric element that is bonded to the diaphragm and outputs a voltage corresponding to the displacement of the second diaphragm, and at least a second vibrating piezoelectric body having a resonance direction in the housing different from that of the first vibrating piezoelectric body. And generating electricity in response to an input to the housing.

(3) The power generation unit of the present invention has a plurality of vibrating piezoelectric bodies that can efficiently convert mechanical energy into electrical energy. In addition, these vibrating piezoelectric bodies resonate at different frequencies (in the present specification, this is appropriately expressed as “different resonance frequencies” for convenience), or resonate with respect to inputs in different directions (in this specification). Then, this is conveniently expressed as “resonance direction is different”).
For this reason, even when inputs having different sizes and directions are added to the housing that houses the vibrating piezoelectric body, the power generation unit of the present invention can widely handle these inputs. As a result, the power generation unit of the present invention can stably absorb mechanical energy and efficiently convert it into electrical energy.

(4) Of course, in the power generation unit of the present invention, it is preferable that the first vibrating piezoelectric body and the second vibrating piezoelectric body that resonate at different frequencies have different resonance directions in the housing.
In this specification, in order to clarify the contents of the present invention, expressions such as “first” and “second” are used for the sake of convenience. The structure and configuration may be the same. The number of vibrating piezoelectric bodies and the like may be at least two in the same housing, and it is more preferable that the number of vibrating piezoelectric bodies or the like having different resonance frequencies and resonance directions is 3 or more. Of course, on the premise that there are a plurality of vibrating piezoelectric bodies having different resonance frequencies and resonance directions, a plurality of vibrating piezoelectric bodies having the same resonance frequency and resonance direction may exist in the same casing.

<< Power generation equipment >>
The power generation unit of the present invention functions as a power generation device by itself, but a plurality of the power generation units can be combined into a power generation device. In any case, since the piezoelectric element according to the present invention generates a voltage according to the amplitude of the diaphragm, the output is normally an alternating current. Considering power supply to devices with low power consumption and increase in output voltage, DC output is often easier to use than AC output. Therefore, it is preferable that there is a rectifier that rectifies the outputs of the first vibrating piezoelectric body and the second vibrating piezoelectric body into a direct current. Furthermore, it is preferable to provide a capacitor or a battery that stores the output from the rectifier, because the supply power or the supply voltage can be stabilized.

  The rectifier may be incorporated in the casing of the power generation unit, or may be provided separately from the power generation unit. The same applies to a capacitor or a battery. The power generation device of the present invention can be interpreted as a power generation unit alone or as a power generation set in which a plurality of power generation units are combined, or as a whole power generation system including the power generation unit or an external device connected to the power generation set. It does not matter either.

<Others>
Unless otherwise specified, “x to y” in the present specification includes a lower limit value x and an upper limit value y. Moreover, the various lower limit value or upper limit value described in this specification can be arbitrarily combined to constitute a range such as “ab”. Furthermore, any numerical value included in the range described in the present specification can be used as an upper limit value or a lower limit value for setting the numerical value range.

It is a fragmentary sectional view which shows the example of a basic structure of the vibration piezoelectric material supported by the cantilever. It is a fragmentary sectional view which shows the example of a basic structure of the vibration piezoelectric material supported at both ends. It is a fragmentary sectional view which shows the basic structural example of the vibration piezoelectric material supported in the center. It is sectional drawing which shows one Embodiment of the electric power generation unit which combined multiple vibrating piezoelectric bodies supported by the cantilever. It is sectional drawing which shows one Embodiment of the electric power generation unit which combined multiple vibration piezoelectric material supported at both ends. It is sectional drawing which shows one Embodiment of the electric power generation unit which combined multiple vibration piezoelectric bodies supported in the center. It is sectional drawing which shows one Embodiment of the electric power generation unit which combined multiple vibration piezoelectric bodies from which the direction to resonate differs. It is sectional drawing which shows one Embodiment of the electric power generation unit which enclosed the amplification fluid in the housing | casing. It is sectional drawing which shows another embodiment of the electric power generation unit with which the amplification fluid was filled into a part of closed space which consists of a housing | casing and a diaphragm. It is sectional drawing which shows one Embodiment of the electric power generation unit which provided the straight-shaped aperture | diaphragm in the flow path of the amplification fluid. It is sectional drawing which shows another embodiment of the electric power generation unit with which the amplification fluid was filled into a part of closed space which consists of a housing | casing and a diaphragm. It is sectional drawing which shows one Embodiment of the electric power generation unit which provided the taper-shaped aperture | diaphragm | restriction in the flow path of the amplification fluid. It is sectional drawing which shows another embodiment of the electric power generation unit with which the amplification fluid was filled into a part of closed space which consists of a housing | casing and a diaphragm. It is a graph which shows the relationship between the mass of the weight provided in the vibration piezoelectric material supported by the cantilever, and the resonance frequency. It is a graph which shows the relationship between the resonant frequency of the vibration piezoelectric material, and an output voltage. It is a circuit diagram of a power generator. It is a graph which shows the time change of the storage voltage by the vibration piezoelectric material supported by the cantilever. It is a graph which shows the relationship between the mass of the weight W provided in the vibration piezoelectric material, and a stored voltage.

DESCRIPTION OF SYMBOLS S Support body P Diaphragm E Piezoelectric element W Weight B Vibrating piezoelectric body C Housing | casing 1-10 Power generation unit

  The present invention will be described in more detail with reference to embodiments of the invention. In addition, the content demonstrated by this specification including the following embodiment can be suitably applied not only to the power generation unit according to the present invention but also to a power generation device including the power generation unit. Therefore, one or two or more configurations arbitrarily selected from the present specification can be added to the configuration of the present invention described above. Note that which embodiment is the best depends on the required specifications and the like.

<Vibrating piezoelectric material>
The vibration piezoelectric body basically includes a vibration plate and a piezoelectric element that is joined to the vibration plate and deforms integrally.
(1) Piezoelectric element A piezoelectric element is an element that generates a voltage by inducing electrical polarization when pressure (deformation) is applied in a specific direction, that is, an element that exhibits a piezoelectric effect. The material, form, type, etc. of the piezoelectric element may be appropriately selected according to the application. Examples of the piezoelectric element material (piezoelectric material) include piezoelectric ceramics such as barium titanate and PZT (lead zirconate titanate: Pb (Zr, Ti) O ₃ ), and KNN ((K, Na) NbO ₃ ). Lead-free piezoelectric ceramics, and piezoelectric single crystals such as lithium tantalate (LiTaO ₃ ). A piezoelectric element is basically an element in which such a piezoelectric body is sandwiched between two electrodes. The piezoelectric element may be either a monomorph type, a bimorph type in which a plurality of piezoelectric bodies are laminated, or a laminated type. Further, an appropriate groove or the like may be formed on the surface of the piezoelectric element (such as a piezoelectric body or an electrode) to adjust the followability (rigidity) to the deformation, the resonance direction, the resonance frequency, and the like.

(2) Diaphragm The diaphragm vibrates in response to an input to the housing and gives displacement to the piezoelectric element, or amplifies or continues the displacement. When the vibrating piezoelectric body resonates, the amplitude of the diaphragm becomes maximum, and the deformation applied to the piezoelectric element also becomes maximum.

  The material, form (shape, size, etc.), etc. of the diaphragm may be selected according to the specifications of the power generation unit. For example, the material of the diaphragm is preferably a material having a small vibration absorbing ability or damping ability in order to increase the amount of power generation. Specifically, there are metal materials such as aluminum, iron, and brass. The form of the diaphragm may also be suitable for input vibration (resonance frequency, resonance direction, amplitude, etc.) to the housing. For example, when the rigidity of the diaphragm decreases, the resonance frequency generally decreases and the amplitude (displacement) increases. Thus, the output of the piezoelectric element can be increased as long as the diaphragm vibrates within the elastic limit. Further, the shape of the diaphragm may be any of a round shape, an oval shape, a square shape, and the like depending on the shape of the piezoelectric element and the housing.

<Amplifier>
(1) The amplifying body is provided on a vibrating piezoelectric body (a vibrating plate or a piezoelectric element), and amplifies the amplitude of the vibrating plate. By this amplifying body, the deformation applied to the piezoelectric element increases, and the output of the power generation unit can be improved.

  The amplifying body is, for example, an amplifying weight disposed on the diaphragm. The amount of amplification of the amplitude of the diaphragm can be adjusted by the mass of the amplifying weight and the arrangement position. Further, the resonance frequency of the vibrating piezoelectric body can be adjusted. For this reason, even if the same diaphragm and piezoelectric element are used, it is possible to easily change the resonance frequency and the resonance direction for each vibrating piezoelectric body simply by changing and adjusting the mass and mounting position of the amplification weight to be arranged. .

(2) The amplifying body may be an amplifying fluid that flows in response to an input to the housing and can press at least one diaphragm. That is, the present invention provides a vibration comprising a housing, a vibration plate disposed in the housing and vibrating in response to an input to the housing, and a piezoelectric element that is joined to the vibration plate and outputs a voltage in accordance with the displacement of the vibration plate. A power generator comprising: a piezoelectric body; and an amplifying fluid that flows according to an input to the housing and presses the diaphragm to amplify the amplitude of the diaphragm, and generates electric power according to the input to the housing It may be a unit.
In consideration of the support structure of the diaphragm, a diaphragm for the amplified fluid may be provided at a position where the amplitude of the diaphragm is further amplified. Furthermore, the direction of the aperture may be adjusted to adjust the amplification direction by the amplification fluid. Further, the amplification fluid may completely fill the closed space defined by the casing and the diaphragm, or may only fill a part thereof. For example, it is preferable that the filling rate of the amplification fluid with respect to the enclosed space is 10 to 100%, further 30 to 100%, because the amount of power generation can be increased.
In addition, the amplifying body may be a collision body (such as a steel ball) that repeatedly collides with the diaphragm in accordance with an input to the housing.

<Case>
The housing supports the above-described vibrating piezoelectric body, particularly the diaphragm, so as to vibrate. The support by the housing may be supported at one point or at two or more points. Specifically, there are cantilever support, both-end support, center support, and the like. By these support methods, the resonance frequency and resonance direction of each vibrating piezoelectric body can also be changed.

  The housing does not necessarily have a box shape surrounding the vibrating piezoelectric body. Moreover, it is not necessary to be a hermetically sealed type. The material, strength, and the like of the housing may be appropriately selected in consideration of the use environment of the power generation unit, the resonance frequency, the resonance direction, and the like. However, the material and form of the housing are preferably those that efficiently transmit to the vibrating piezoelectric body without absorbing or attenuating external force or vibration.

<< Embodiment of power generation unit >>
Specific examples of the power generation unit are shown in FIGS.
(1) The basic structure of the power generation unit of the present invention is illustrated in FIGS. A power generation unit 1 partially shown in FIG. 1 includes a diaphragm P made of metal (for example, spring steel), a piezoelectric element E in which one electrode is joined to the diaphragm P, and one end side of the diaphragm P. And a weight W disposed on the other end side of the diaphragm P. The support S1 can also be used as a housing.
Hereinafter, the diaphragm P and the piezoelectric element E are referred to as a vibrating piezoelectric body B, but may be appropriately referred to as a vibrating piezoelectric body B including the weight W. Also, members having basically the same structure or action will be described with the same reference numerals for the sake of convenience within a range that does not cause confusion.

  In the case of the power generation unit 1, the support structure of the diaphragm P is a so-called cantilever type (cantilever). The deflection (deformation) of the diaphragm P can be a maximum in the illustrated vibration direction. Since the weight W (amplifier) is provided at the tip, the deflection of the diaphragm P is amplified and becomes larger toward the tip. That is, when an excitation force that vibrates (excites) in the illustrated vibration direction is input from the outside to the support S1, the diaphragm P is greatly deformed (bent), and a large output of the piezoelectric element E is expected.

  The power generation unit 2 shown in FIG. 2 is a case where both ends of the diaphragm P are supported by the support S2, and a weight W is disposed at the center of the upper surface of the piezoelectric element E joined to the center of the diaphragm P. The power generation unit 2 is further provided with a weight W in the central portion where the deflection is originally increased in the support structure. For this reason, when an excitation force that vibrates (excites) in the illustrated vibration direction is input from the outside to the support S2, the diaphragm P is greatly deformed (bent) near the center, and a large output of the piezoelectric element E is expected. Is done.

  The power generation unit 3 shown in FIG. 3 is a case where the center of the diaphragm P is supported by the support S3, and weights W11 and W12 are disposed at both ends of the diaphragm P. Also in this case, the weight W11 and the weight W12 are provided at the end portions where the deflection of the diaphragm P is increased in the support structure. Therefore, when an excitation force that vibrates (excites) in the illustrated vibration direction is input from the outside to the support S3, the diaphragm P is greatly deformed (bent) near both ends, and a large output of the piezoelectric element E is expected. Is done.

(2) FIGS. 4 to 6 illustrate power generation units in which a plurality of vibrating piezoelectric bodies supported by various methods as shown in FIGS.
The power generation unit 4 shown in FIG. 4 is one in which three vibrating piezoelectric bodies B1, B2, and B3 that are cantilevered in one casing C4 are vertically arranged in a vertical direction. The diaphragms P1, P2, and P3 and the piezoelectric elements E1, E2, and E3 constituting the respective vibrating piezoelectric bodies B1, B2, and B3 are the same. However, the weights W1, W2, and W3 disposed at the ends of the diaphragms P1, P2, and P3 have different masses. For this reason, the frequencies at which the vibrating piezoelectric bodies B1, B2, and B3 resonate also differ depending on the masses of the weights W1, W2, and W3.
When an excitation force in the illustrated vibration direction is input from the outside to the housing C4, at least one of the diaphragms P1, P2, and P3 swings greatly on the open end side in a wide frequency range. Thereby, a large output (power generation) can be stably obtained in a wide vibration frequency range (so-called broadband).

  The outputs of the piezoelectric elements E1, E2, E3 are guided to output terminals provided outside the housing C4. One of the output terminals is connected to each end of each diaphragm P1, P2, P3 to which one electrode of each piezoelectric element E1, E2, E3 is joined. The other of the output terminals is connected to the other electrode of each of the piezoelectric elements E1, E2, and E3. In the following embodiments, the connection method is basically the same, and the description regarding the connection is omitted as long as it is.

The power generation unit 5 shown in FIG. 5 is one in which three vibrating piezoelectric bodies B1, B2, B3 supported at both ends in one casing C5 are vertically arranged in a vertical direction.
The diaphragms P1, P2, and P3 and the piezoelectric elements E1, E2, and E3 constituting the respective vibrating piezoelectric bodies B1, B2, and B3 are the same. However, the masses of the weights W1, W2, and W3 arranged at the center of each back surface (the surface on which the piezoelectric elements E1, E2, and E3 are not arranged) of the diaphragms P1, P2, and P3 are different. For this reason, the frequencies at which the vibrating piezoelectric bodies B1, B2, and B3 resonate are different.
When an excitation force in the illustrated vibration direction is input from the outside to the housing C5, at least one of the diaphragms P1, P2, and P3 swings largely near the center in a wide frequency range, and a large output (power generation) is generated. It can be obtained stably in a wide vibration frequency range (broadband).

The power generation unit 6 shown in FIG. 6 has three vibrating piezoelectric bodies B1, B2, and B3 supported at the center in one casing C6 arranged in a vertical column. The diaphragms P1, P2, and P3 and the piezoelectric elements E1, E2, and E3 constituting the respective vibrating piezoelectric bodies B1, B2, and B3 are the same. Here, the masses of the weights W11, W12, W13, and the weights W21, W22, W23 are the same or different on the left and right, and are different on the top and bottom. For example, the masses of the weights W11, W12, and W13 in the vertical direction may be different from each other, and the masses of the left and right weights W11 and W12 may be different from each other. The resonating frequency differs between vibrating piezoelectric bodies having different masses of weights. When the masses of the six weights are different from each other, the frequency at which each vibrating piezoelectric body resonates becomes wider.
When an excitation force in the illustrated vibration direction is input from the outside to the housing C6, at least one of the diaphragms P1, P2, and P3 swings greatly at both ends or one end side in a wider frequency range. In this way, the output (power generation) of the power generation unit 6 can be stably obtained in a wider vibration frequency range (broadband).

(3) The power generation unit 7 shown in FIG. 7 has four vibrating piezoelectric bodies B1, B2, B3, and B4 arranged in a rhombus shape in one casing C7. One end sides of the vibrating piezoelectric bodies B1, B2, B3, B4 are respectively supported by the inner wall surfaces of the housing C7, and the other end sides thereof are open ends.
The diaphragms P1, P2, P3, and P4 and the piezoelectric elements E1, E2, E3, and E4 constituting the vibrating piezoelectric bodies B1, B2, B3, and B4 are the same. Further, the weights W1, W2, W3, and W4 disposed at the ends of the diaphragms P1, P2, P3, and P4 are the same.
Even if there are inputs to the housing C7 from various directions as shown in the figure, at least one of the diaphragms P1, P2, P3, and P4 is highly likely to swing significantly on the tip side. For this reason, even if the input direction is not constant, the output (power generation) can be stabilized.

(4) FIGS. 8A, 8B, 9A, 9B, 10A and 10A and 10B show the power generation unit in which the vibrating piezoelectric body B supported at both ends is disposed in the housing C and the amplified fluid L is placed in the housing C. Exemplified in 10B. The vibrating piezoelectric body B has a piezoelectric element E bonded to the center of the diaphragm P, and a weight W is disposed on the piezoelectric element E. For convenience, only one vibrating piezoelectric body B is shown in the drawings, but it goes without saying that it is preferable to provide a plurality of vibrating piezoelectric bodies B.
The power generation unit 8 shown in FIG. 8A is obtained by enclosing an amplification fluid L in a casing C so as to be in contact with the entire back surface of the diaphragm P (that is, a filling rate of 100%). The power generation unit 8 ′ shown in FIG. 8B is obtained by enclosing the amplified fluid L only in a part of the sealed space formed by the diaphragm P and the casing C.
Further, in the power generation unit 9 shown in FIG. 9A, a straight throttle N1 is provided in the housing C so that the amplified fluid L contacts only the center of the back surface of the diaphragm P. The power generation unit 9 ′ shown in FIG. 9B is obtained by enclosing the amplified fluid L only in a part of the sealed space formed by the diaphragm P and the casing C. The power generation unit 10 shown in FIG. 10A is obtained by changing the diaphragm N1 to a tapered diaphragm N2. The power generation unit 10 ′ shown in FIG. 10B is obtained by enclosing the amplified fluid L only in a part of the sealed space formed by the diaphragm P and the casing C. By changing the shape of these diaphragms, the flow rate of the amplified fluid L that contacts the back surface of the diaphragm P can be adjusted. Although not shown, the direction in which the amplified fluid comes into contact with the back surface of the diaphragm P can be changed by adjusting the direction of the diaphragm. This facilitates adjustment of the vibrating piezoelectric body in the resonance direction with the amplified fluid.

In the case of the power generation units 8, 8 ′, 9, 9 ′, 10, 10 ′, when an excitation force is input to the casing C, the fluid pressure of the amplified fluid L acts on the entire surface or a part of each diaphragm P. To do. As a result, the deformation or amplitude of the diaphragm P is amplified. In particular, the amount of bending at the center of the diaphragm P can be maximized. In this way, output improvement by the power generation units 8, 8 ′, 9, 9 ′, 10, 10 ′ can be expected.
In the case of the power generation units 8, 9, 10, even if the input direction to the housing C is different from the resonance direction of the vibrating piezoelectric body B, the fluid pressure by the amplified fluid L is applied to the diaphragm P based on the Pascal principle. Can work. Thereby, the output of these electric power generation units can increase. In this respect, the amplified fluid is more effective in improving the output than the impact body such as a hard sphere is used as the amplification body.

<Others>
The power generation unit or power generation apparatus of the present invention can be used in various fields and environments. The form of input to the housing of the power generation unit does not matter. For example, atmospheric pressure fluctuations (vibrations) such as sound and wind, load fluctuations that occur on the floor or road when people or vehicles move, and vibrations of various devices are representative. Examples of the driving target by the generated power include illumination such as LEDs, driving of a small motor, a small charging device, and various sensor power sources.

The present invention will be described more specifically with reference to examples.
<< Resonance frequency and output voltage >>
(1) The relationship between the resonance frequency and the output voltage was examined using the power generation unit 1 having the structure shown in FIG. For the piezoelectric element E, 7BB-27-4LO manufactured by Murata Manufacturing Co., Ltd. having an outer diameter of 20 mm and a thickness of 0.25 mm was used. A brass ring was used for the diaphragm P. Using this piezoelectric element E and diaphragm P, a disc-shaped vibrating piezoelectric body B having an outer diameter of 27 mm, a thickness of 0.3 mm, and a mass of 2 g was manufactured. One end of the diaphragm P was fixed to the support S. The support S1 has a cylindrical shape made of SUS. The vibrating piezoelectric body B was fixed to the support S with screws. As weights attached to the other end of the diaphragm P, 1 g weight W and 2 g weight W were prepared.

  A sine wave having a vibration acceleration of 1 G was input to the support S, and the vibrating piezoelectric body B was vibrated. At this time, the resonance frequency of the vibrating piezoelectric body B (including the weight W) and the output voltage of the piezoelectric element E were examined. In the test, when the weight P was not attached to the diaphragm P, and when the weight W of 1 g (mass ratio to the vibrating piezoelectric body B: 0.5) or 2 g (mass ratio to the vibrating piezoelectric body B: 1) was attached. The following three patterns were performed. The obtained results are shown in FIG. 11 and FIG.

(2) FIG. 11 shows that the resonance frequency decreases as the mass of the weight W attached to the tip of the vibrating piezoelectric body B increases. From FIG. 12, it was found that the output voltage increases as the resonance frequency decreases. Therefore, if the frequency of the excitation source is constant, a larger output voltage can be obtained as the mass of the weight W is increased.

In any case, it has been clarified that the frequency at which the vibrating piezoelectric body B resonates can be easily changed by changing the mass of the weight W. Therefore, by adjusting the mass and arrangement of the weight W, it is possible to easily obtain a power generation unit that performs stable power generation in response to a broadband input. That is, if the power generation unit according to the present invention is used, vibration energy can be efficiently and stably converted into electric energy.
The case where the power generation unit 1 having the structure shown in FIG. 1 is used has been described. However, when the power generation unit 2 having the structure shown in FIG. 2 is used, the power generation unit 3 having the structure shown in FIG. 3 is used. Even in this case, the effect is the same.

<Storage voltage>
The power generation unit 1 described above was incorporated in the circuit shown in FIG. This circuit includes a diode bridge rectifier circuit connected to the output terminal of the power generation unit and a capacitor connected in parallel downstream thereof. The stored voltage is a measurement of the terminal voltage of the capacitor.
The stored voltage when a single impact vibration was input to the power generation unit 1 was measured. The size, mass, and the like of the vibrating piezoelectric body B were as described above, and the energy of the applied impact vibration was 0.013J.

  FIG. 14 shows the relationship between the time variation of the stored voltage and the mass of the weight W, and FIG. 15 shows the relationship between the stored voltage and the mass of the weight W. From both figures, it can be seen that as the mass of the weight W increases, the stored voltage increases and the power generation efficiency improves. Moreover, it was found from FIG. 14 that even when the applied impact vibration is single, using the power generation unit 1 according to the present invention, a stable storage voltage can be obtained for a long time. This is because the vibration of the diaphragm P continues. Needless to say, the same effect can be obtained even when the power generation unit 2 of FIG. 2 or the power generation unit 3 of FIG. 3 is used.

Claims (10)

A housing,
A first diaphragm disposed in the casing and vibrating in response to an input to the casing; a first piezoelectric element that is joined to the first diaphragm and outputs a voltage in accordance with the displacement of the first diaphragm; A first vibrating piezoelectric body comprising:
A second diaphragm that is disposed in the casing and vibrates in response to an input to the casing; a second piezoelectric element that is joined to the second diaphragm and outputs a voltage corresponding to the displacement of the second diaphragm; And comprising at least a second vibrating piezoelectric body that resonates at a different frequency from the first vibrating piezoelectric body,
A power generation unit that generates power in response to an input to the housing.   2. The power generation unit according to claim 1, wherein the first vibration piezoelectric body and the second vibration piezoelectric body further have different resonance directions in the housing.   The power generation unit according to claim 1, further comprising an amplifier that amplifies the amplitude of the first diaphragm and / or the second diaphragm.   The amplifying body flows in response to an input to the amplifying weight disposed in the first vibrating piezoelectric body and / or the second vibrating piezoelectric body, or the housing, and / or the first vibrating plate and / or the first vibrating body. The power generation unit according to claim 3, wherein the power generation unit is an amplifying fluid capable of pressing the two diaphragms.   5. The power generation unit according to claim 4, wherein a mass ratio of the amplification weight with respect to the first vibrating piezoelectric body or the second vibrating piezoelectric body is 0.3-2. A housing,
A first diaphragm disposed in the casing and vibrating in response to an input to the casing; a first piezoelectric element that is joined to the first diaphragm and outputs a voltage in accordance with the displacement of the first diaphragm; A first vibrating piezoelectric body comprising:
A second diaphragm that is disposed in the casing and vibrates in response to an input to the casing; a second piezoelectric element that is joined to the second diaphragm and outputs a voltage corresponding to the displacement of the second diaphragm; And comprising at least a second vibrating piezoelectric body having a resonance direction different from that in the first vibrating piezoelectric body,
A power generation unit that generates power in response to an input to the housing. A housing,
A vibrating piezoelectric body comprising a diaphragm disposed in the casing and vibrating in response to an input to the casing, and a piezoelectric element joined to the diaphragm and outputting a voltage in accordance with the displacement of the diaphragm;
An amplification fluid that flows according to an input to the housing and presses the diaphragm to amplify the amplitude of the diaphragm;
A power generation unit that generates power in response to an input to the housing.   The power generation unit according to claim 7, wherein the amplification fluid has a filling rate of 10 to 100% with respect to a closed space defined by the casing and the diaphragm. The power generation unit according to claim 1,
A rectifier that rectifies the outputs of the first vibrating piezoelectric body and the second vibrating piezoelectric body to direct current;
A power generation device comprising:   Furthermore, the electric power generating apparatus of Claim 9 provided with a capacitor | condenser or a battery downstream of the said rectifier.

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