JP2011250536A - Method for manufacturing piezoelectric power generating unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a piezoelectric power generating unit which can dispense with wiring and have a very strong portion to fix a piezoelectric element.SOLUTION: A one-side supporting type piezoelectric power generating unit 50 supports one side of a piezoelectric bimorph having an elastic plate inserted and bonded together between two piezoelectric ceramic boards 1, 2, and generates electricity by external force applied to this piezoelectric bimorph. In manufacturing the piezoelectric power generating unit 50, the piezoelectric bimorph is inserted and fixed between a U-shaped first fixing member 4 and a columnar second fixing member 5.

Description

  The present invention relates to a method for manufacturing a piezoelectric power generation unit that utilizes electrical energy generated when a piezoelectric material is deformed or vibrated by an external force, and particularly relates to a method for fixing a power generation piezoelectric element.

  Attempts have been made to use electrical energy generated when a piezoelectric material is distorted. Conventionally, when power is generated by this type of piezoelectric element, usually an impact body such as a metal sphere or ceramic sphere collides with the piezoelectric element, or one end of the piezoelectric element is fixed and the opposite end is pressed and deformed. Then, power is generated by the distortion of the piezoelectric element. The electric power generated at this time is used for light emission of the illuminant, or the secondary battery is charged and taken out. In Patent Document 1, a piezoelectric bimorph element is supported on one end of a fan, a light emitter or music box IC is attached to the surface facing the fan, power is generated by deformation of the surface facing the fan, and the light emitter is generated by this electric energy. A fan that emits light or sounds a music box is disclosed. Patent Document 2 discloses an invention that generates electricity by fixing a piezoelectric bimorph with a single beam and applying a force to the opposite end.

  In such an application, as a method of fixing the piezoelectric bimorph vibrator supported at one end, a method of fixing with the one-sided beam is generally used. FIG. 6 is a perspective view for explaining a method of fixing with a single cantilever in a conventional piezoelectric power generation unit. As shown in FIG. 6, the conventional piezoelectric power generation unit 100 uses an acrylic prismatic body 11 and is arranged so that one end of the piezoelectric bimorph 70 is sandwiched from above and below, and the electrodes 70 a on the upper and lower surfaces of the piezoelectric bimorph 70 are disposed. Solders the wires 12 and 13 to make electrical connection. The element is generally fixed by bonding with an adhesive or sandwiching with a plate material or the like.

  Further, in Patent Document 3, the piezoelectric bimorph is cantilevered, and a recess is provided in a portion where the piezoelectric element on the free end side is displaced so that the displaced tip of the piezoelectric bimorph does not come into contact, thereby constituting a piezoelectric power generation device. The invention is disclosed.

JP-A-8-56728 Japanese Patent Laid-Open No. 9-182465 JP-A-7-107752

  However, in these methods, there is a problem that the board portion to be attached is thick, the thickness of the power generation device is thick, and there is a restriction in installation. Further, in the method of Patent Document 3, it is necessary to perform electrical connection by soldering an electric wire or the like, which increases the number of electric wire connection points and increases the number of operations, or mechanical force such as vibration continuously during use. However, there was a problem in the reliability of the soldered part, such as the wiring part coming off. Further, in the method of Patent Document 3, it is necessary to fix the piezoelectric bimorph by bonding with an adhesive or the like, but there is a problem that the bonding surface is peeled off due to the influence of vibration or the like.

  Accordingly, an object of the present invention is to provide a method of manufacturing a piezoelectric power generation unit that eliminates wiring and has a high strength of a fixing portion of a piezoelectric element.

  In order to solve this drawback, the present invention makes one of the piezoelectric bimorph or piezoelectric unimorph fixing members U-shaped, and sandwiches the piezoelectric bimorph between the inner portion and the other fixing member of the pair. It is characterized in that the material of this part is a conductor such as brass, phosphor bronze, etc., and that these fixed parts are fixed to the land part formed on the substrate to serve both as electrical connection and fixing. .

  That is, according to the present invention, there is provided a one-end support type piezoelectric power generation unit that supports one end of a piezoelectric bimorph having an elastic plate sandwiched between two piezoelectric ceramic plates and generates power by an external force applied to the piezoelectric bimorph. A method of manufacturing a piezoelectric power generation unit, characterized in that the piezoelectric bimorph is sandwiched and fixed between a U-shaped first fixing member and a columnar second fixing member. .

  According to the present invention, the first fixing member includes a shaft portion and two upright portions connected to both ends of the shaft portion, and the electrode provided on the piezoelectric ceramic plate is connected to the inner side of the shaft portion. And it fixes so that the one surface of the said 2nd fixing member may contact, and it electrically connects, The manufacturing method of said piezoelectric power generation unit characterized by the above-mentioned is obtained.

  Further, according to the present invention, there is provided a method for manufacturing a one-end support type piezoelectric power generation unit that supports one end of a piezoelectric unimorph obtained by bonding a piezoelectric ceramic plate and an elastic plate and generates power by an external force applied to the piezoelectric unimorph. Thus, a method of manufacturing a piezoelectric power generation unit is obtained, in which the piezoelectric unimorph is sandwiched and fixed between a U-shaped first fixing member and a columnar second fixing member.

  According to the present invention, the first fixing member includes a shaft portion and two upright portions connected to both ends of the shaft portion, and the electrode provided on the piezoelectric ceramic plate is connected to the inner side of the shaft portion. Alternatively, the piezoelectric power generation unit manufacturing method described above is characterized in that one surface of the second fixing member is fixed so as to be in contact with and electrically connected.

  As a result, according to the present invention, it is possible to provide a method for manufacturing a piezoelectric power generation unit that can omit wiring, improve the durability of the element and the durability of the wiring during continuous use, and improve the reliability of the wiring. . In addition, by sandwiching and fixing a piezoelectric bimorph or a piezoelectric unimorph, it is possible to provide a method for manufacturing a piezoelectric power generation unit having a high strength of the fixed portion of the piezoelectric element.

Sectional drawing of the piezoelectric power generation unit in one embodiment of this invention. The perspective view of the piezoelectric power generation unit in one embodiment of this invention. The figure which shows the electrical connection method of the piezoelectric bimorph used for the piezoelectric power generation unit in one embodiment of this invention. FIG. 3A is a diagram showing parallel connection. FIG. 3B shows a series connection. The perspective view which shows the fixing method of the piezoelectric power generation unit in one embodiment of this invention. The perspective view which shows the state after fixing the piezoelectric power generation unit in one embodiment of this invention. The perspective view which shows the fixing method with the single cantilever in the conventional piezoelectric power generation unit. The figure which shows the voltage output waveform of this invention and the conventional piezoelectric power generation unit. Fig.7 (a) is a figure which shows the case of the piezoelectric power generation unit of this invention. FIG.7 (b) is a figure which shows the case of the conventional piezoelectric power generation unit. The figure which shows the continuous test result of this invention and the conventional piezoelectric power generation unit.

BEST MODE FOR CARRYING OUT THE INVENTION

  The details of the embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a piezoelectric power generation unit according to an embodiment of the present invention. FIG. 2 is a perspective view of the piezoelectric power generation unit according to the embodiment of the present invention.

  As shown in FIGS. 1 and 2, a single-end supported power generation piezoelectric bimorph 20 according to an embodiment of the present invention includes two piezoelectric ceramic plates 1 and 2 and an elastic plate which is an intermediate layer sandwiched between the two plates. It is composed of three. The piezoelectric ceramic plates 1 and 2 are generally rectangular, but they may be isosceles triangles or trapezoids with the fixed end side as a base, but can be applied to either case. Electrodes (electrodes 20a on the piezoelectric ceramic plate 1) are formed on the surfaces of the piezoelectric ceramic plates 1 and 2, respectively. These electrodes are formed by a silver baking electrode, plating, sputtering, or the like. Various materials such as a metal plate, a glass epoxy substrate, a carbon fiber material, and a glass fiber material are used for the elastic plate 3 as an intermediate layer.

  A U-shaped first fixing member 4 and a columnar second fixing member 5 are arranged at one end perpendicular to the long side direction of the piezoelectric bimorph 20. For the U-shaped first fixing member 4 and the columnar second fixing member 5, a conductor such as phosphor bronze or brass can be used. The U-shaped first fixing member 4 includes a shaft portion and two upright portions connected to both ends thereof. The electrode 20a of the piezoelectric ceramic plate 1 is disposed inside the shaft portion of the U-shaped first fixing member 4 so that the electrode of the piezoelectric ceramic plate 2 and one surface of the columnar second fixing member 5 are in contact with each other. A screw hole 4a is provided in each of the front end surfaces of the two upright portions of the U-shaped first fixing member 4 so that the screw 6 can be fixed. In addition, screw holes 5a are provided at two locations on both ends of the columnar second fixing member 5 in the long side direction on the surface facing the surface of the piezoelectric ceramic plate 2 in contact with the electrode. The fixing members 4 and 5 are screwed to the glass epoxy substrate 7 so that the piezoelectric bimorph 20 is sandwiched between the fixing members 4 and 5 in a positional relationship. By fixing the fixing members 4 and 5 to the electrodes on the surface of the piezoelectric bimorph, the terminals on the load side, and the lands, both the electrical connection and the fixing of the piezoelectric element are achieved.

  In a normal piezoelectric bimorph connection method, the electrode bonded to the intermediate layer of one piezoelectric ceramic element and the electrode bonded to the intermediate layer of the other piezoelectric ceramic element may be used in conduction. Many. Among the above materials, if the conductor is a metal plate or the like, the electrode on the side bonded to the intermediate layer of one piezoelectric ceramic element and the electrode on the side bonded to the intermediate layer of the other piezoelectric ceramic element by bonding However, when an insulator such as a glass epoxy substrate is used, an electrode pattern is formed on the surface of the elastic plate as the intermediate layer, and the surface electrode of the piezoelectric ceramic plate is brought into contact with this portion. It is necessary to take out the extended portion of the elastic plate, take out the electrode at a portion other than the adhesive surface, and establish conduction.

  3A and 3B are diagrams showing a method of electrically connecting piezoelectric bimorphs used in the piezoelectric power generation unit according to the embodiment of the present invention. FIG. 3A is a diagram showing parallel connection, and FIG. It is a figure which shows a serial connection. As shown in FIG. 3A, the piezoelectric bimorph connection method includes a parallel connection in which the respective surface electrodes of the piezoelectric ceramic plates 1 and 2 are short-circuited and an output is taken out from the elastic plate 3 of the intermediate layer. As shown in FIG. 3B, there is a series connection in which output is taken out between the surface electrodes of the piezoelectric ceramic plates 1 and 2. When the same force is applied to a piezoelectric bimorph of the same size and compared, the parallel connection has a characteristic that a higher output can be obtained with a lower load resistance than the series connection, and a mechanical input is given to the piezoelectric element to extract electric energy. For many applications, parallel connection is often used.

  The piezoelectric power generation unit using the single-end supported power generation piezoelectric bimorph thus configured is attached and fixed to the glass epoxy substrate as follows. FIG. 4 is a perspective view showing a method of fixing the piezoelectric power generation unit according to the embodiment of the present invention. FIG. 4 shows an example in which the elastic plate as an intermediate layer is a metal and the connection method is a series connection. As shown in FIG. 4, solder-plated lands 8 and 9 are formed on a glass epoxy substrate 7, and a rectifier circuit 10 is installed on these lands 8 and 9. With this rectifier circuit 10, it is possible to rectify AC-attenuated power generated when an input is applied to the piezoelectric bimorph, convert it into positive component power, and cause a light emitter such as an LED to emit light. A certain amount can be stored in the secondary battery and taken out as necessary. In the piezoelectric power generation unit 50 of the present invention, the piezoelectric bimorph 20 is screwed onto the glass epoxy substrate 7 by the fixing members 4 and 5. Thus, an electrical connection can be obtained simply by screwing and fixing the piezoelectric bimorph 20. Further, the surface electrode of the piezoelectric bimorph 20 and the fixing members 4 and 5 are brought into contact with each other when the piezoelectric element is sandwiched, and conduction is obtained. A conductive adhesive or the like may be applied to the contact portion in order to stabilize the electrical connection and stabilize the strength. When a force is applied to the side opposite to the fixed end in this state, the electric energy generated from the piezoelectric bimorph 20 can be taken out.

  For the fixing method of the present invention, in addition to the above-described screwing method, a method of adhering the fixing member with an adhesive or the like can be used, and it does not come off when a force is applied to the opposite end of the fixed end It is only necessary that the fixing is performed and electrical connection between the fixing member and the land or terminal portion formed on the fixing portion such as the substrate is obtained.

  A piezoelectric unimorph can also be used as the piezoelectric element. In this case, the elastic plate is directed toward the substrate side, and is arranged so that the electrode of the piezoelectric ceramic plate and the inside of the shaft portion of the U-shaped first fixing member are in contact with one surface of the elastic plate and the columnar second fixing member. Or with the electrode of the piezoelectric ceramic plate facing the substrate side, one side of the electrode of the piezoelectric ceramic plate and the columnar second fixing member, the inside of the shaft portion of the elastic plate and the U-shaped first fixing member It can be fixed in the same manner as a piezoelectric bimorph by arranging it in contact and fixing it to the substrate.

  Next, the fixing method according to the present invention was compared with the conventional fixing method. FIG. 5 is a perspective view showing a state after fixing the piezoelectric power generation unit according to the embodiment of the present invention. FIG. 6 is a perspective view showing a fixing method using a single cantilever in a conventional piezoelectric power generation unit. The piezoelectric ceramic plates in the piezoelectric bimorphs 20 and 70 shown in FIGS. 5 and 6 were each made of NEC TOKIN N10 material having a length of 35 mm, a width of 10 mm, and a thickness of 0.25 mm. A brass plate having a length of 36 mm, a width of 11 mm, and a thickness of 0.5 mm was used as an elastic plate as an intermediate layer. Further, in fixing the piezoelectric bimorph to the substrate, brass was used for the fixing members 4 and 5 of this example. In the conventional example, an acrylic prism body 11 having a length of 22 mm, a width of 6 mm, and a thickness of 6 mm is used, and is arranged so as to be sandwiched from above and below the piezoelectric bimorph 70. 13 was soldered to make an electrical connection.

  FIG. 7 shows voltage output waveforms of the present invention and a conventional piezoelectric power generation unit. FIG. 7A is a diagram showing the case of the piezoelectric power generation unit of the present invention, and FIG. 7B is a diagram showing the case of the conventional piezoelectric power generation unit. In the experiment, a 1 G acceleration input was applied at 10 times / sec from the bottom to the substrate on which the piezoelectric bimorph was fixed, the piezoelectric bimorph was deformed and freely oscillated, and the voltage output at this time was observed with an oscilloscope. From FIG. 7, there is almost no difference in the output by power generation between the method of the present invention and the conventional example.

  Next, an experiment was conducted to confirm durability by continuously generating power from the bottom surface. FIG. 8 is a diagram showing the results of continuous tests of the present invention and a conventional piezoelectric power generation unit. Five bimorphs of the present invention and the conventional method were continuously tested. The horizontal axis indicates the number of power generations and the vertical axis indicates the output voltage. In the conventional method, an element whose output has decreased or has not been output has been generated more than 100,000 times. This is because the conductive wire connected every time the surface of the piezoelectric element is displaced is disconnected due to repeated vibration, and an output cannot be obtained. On the other hand, in this invention, even if it exceeded 1 million times, the fall of an output was not seen but durability improved.

  Needless to say, the present invention is not limited to the above-described embodiment, and the design can be changed according to the purpose and application. For example, the piezoelectric bimorph, the piezoelectric ceramic plate constituting the piezoelectric unimorph, the material and shape of the elastic body, and the like can be selected according to the application.

  In addition, the present invention operates as a power generator as long as there is a mechanical input such as vibration without a power source such as a battery, and the electric power is stored directly or in a capacitor or the like, and electric energy is taken out as necessary to emit light emitting diodes. It can be applied to the light emission of the light source and the power source of the transmitter.

DESCRIPTION OF SYMBOLS 1, 2 Piezoelectric ceramic board 3 Elastic board 4 (1st) fixing member 4a Screw hole 5 (2nd) fixing member 5a Screw hole 6 Screw 7 Glass epoxy board | substrates 8 and 9 (Solder-plated) land 10 Rectification circuit 11 prismatic body 12, 13 electric wire 20, 70 piezoelectric bimorph 20a, 70a electrode 50, 100 piezoelectric power generation unit

Claims (4)

  A method of manufacturing a one-end support type piezoelectric power generation unit that supports one end of a piezoelectric bimorph having an elastic plate sandwiched between two piezoelectric ceramic plates and generates power by an external force applied to the piezoelectric bimorph. A method for manufacturing a piezoelectric power generation unit, wherein the piezoelectric bimorph is sandwiched and fixed between a first fixing member having a square shape and a second fixing member having a columnar shape.   The first fixing member includes a shaft portion and two upright portions connected to both ends of the shaft portion. The electrodes provided on the piezoelectric ceramic plate are connected to the inner side of the shaft portion and the second fixing member. 2. The method of manufacturing a piezoelectric power generation unit according to claim 1, wherein one surface is fixed and is electrically connected.   A method of manufacturing a one-end support type piezoelectric power generation unit that supports one end of a piezoelectric unimorph obtained by bonding a piezoelectric ceramic plate and an elastic plate and generates electric power by an external force applied to the piezoelectric unimorph. A method for manufacturing a piezoelectric power generation unit, wherein the piezoelectric unimorph is sandwiched and fixed between one fixing member and a columnar second fixing member.   The first fixing member includes a shaft portion and two upright portions connected to both ends of the shaft portion, and an electrode provided on the piezoelectric ceramic plate is connected to the inner side of the shaft portion or the second fixing member. 4. The method of manufacturing a piezoelectric power generation unit according to claim 3, wherein one surface is fixed and electrically connected.

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