JP2006262575A - Generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact generator with high generation efficiency and high operability in performing a human key operation. <P>SOLUTION: This generator 10 includes a flexible piezoelectric element 11; a support member 15 for flexibly supporting the piezoelectric element 11; and a buckling spring 14. The piezoelectric element 11 rapidly bends and deforms for power generation when the buckling spring 14 is pressed and buckled through the piezoelectric element 11 by applying an external force F to the piezoelectric element 11 or when the external force F applied to the piezoelectric element 11 is removed to restore the buckling spring 14 to its original shape. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power generation device configured using a piezoelectric element.

  2. Description of the Related Art In recent years, application development of power generation apparatuses using a piezoelectric element such as a bimorph type that has flexibility and generates electric power by bending under external force has been actively performed. For example, the portable telephone disclosed in Patent Document 1 has a piezoelectric element built in the casing, and the piezoelectric element inside the casing is subjected to mechanical stress due to external vibration received when carried or in a vehicle. A power generation device is described in which electric energy to be stored is stored in a secondary battery or a capacitor, and the stored electric energy is used as auxiliary energy for a power supply battery. More specifically, in this power generation device, one end of a rectangular piezoelectric element is fixed, a weight is attached to the other end as a free end, and acceleration is applied to the weight to bend and vibrate the piezoelectric element. The piezoelectric element is generating electricity.

  However, when the acceleration acting on the mobile phone is used when carrying, if the direction of the acceleration and the direction of bending of the piezoelectric element do not match, a large displacement cannot be obtained, and if the piezoelectric element is bent slowly, it becomes large. Since a voltage cannot be generated, it is considered difficult to obtain high power generation efficiency with such a power generation device.

In addition, as a method of using a mobile phone, it is also true that e-mail is frequently used. In this case, since the key is pressed many times, it is possible to realize a compact power generator using this pressing force. If possible, it will be very useful in assisting power batteries. Not only a mobile phone but also a portable electronic device such as a notebook computer can be used effectively to assist a power supply battery if power can be generated by tapping the keyboard. In this way, when a person taps a key to generate power, it is necessary to consider that the touch feeling is natural and real, that is, the operability is good.
JP 2002-171341 A

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a compact and highly efficient power generation apparatus. It is another object of the present invention to provide a power generation device with good operability when a key operation is performed by a person.

According to the present invention, there is provided a piezoelectric element having flexibility, a support member that supports the piezoelectric element so as to be bent, and a buckling spring.
When the buckling spring is buckled by applying an external force to the piezoelectric element and the buckling spring is buckled by the piezoelectric element, and the external force applied to the piezoelectric element is removed, the buckling is performed. Provided is a power generation device characterized in that when a spring returns to its original shape, it is bent to generate power.

  In this power generation device, it is preferable that the piezoelectric element is in contact with the buckling spring in a state where no external force is applied to the piezoelectric element. Thereby, when a person presses a piezoelectric element, it is possible not to confuse the feeling that the piezoelectric element and the buckling spring are in contact with the feeling that the buckling spring is buckled. A piezoelectric element having a rectangular shape is suitable, and it is preferable that one end or both ends in the longitudinal direction be supported by a support member. In the structure in which the piezoelectric element is supported at both ends, a structure in which a constant force is applied in the longitudinal direction of the piezoelectric element to hold the piezoelectric element in a bent state is preferable. In such a structure, when a pressing force is applied to the piezoelectric element, it is possible to cause a steep bending deformation in the piezoelectric element by utilizing the spring property of the piezoelectric element itself in addition to the deformation of the buckling spring. Even when the pressing force applied to the piezoelectric element is removed, the piezoelectric element can be easily returned to the original posture by utilizing the spring property of the piezoelectric element itself, and thus the power generation efficiency can be improved.

  In the present invention, since the piezoelectric element rapidly displaces when the buckling spring is buckled, large electric energy can be generated in the piezoelectric element, and the piezoelectric element and the buckling spring overlap in the direction in which the pressing force is applied. Since it arrange | positions in this way, there exists the outstanding effect that it can be set as a compact structure. In addition, when a person applies a pressing force to the piezoelectric element, the present invention can realize that the key has been pressed with a feel when buckling deformation occurs in the buckling spring. There is an effect.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a schematic structure and an operation state of the power generation apparatus 10. As shown in FIG. 1A, the power generation apparatus 10 includes a flexible piezoelectric element 11 formed by bonding a reinforcing plate 13 and a piezoelectric plate 12, and supports the piezoelectric element 11 so as to be bent. And a buckling spring 14.

  The piezoelectric plate 12 is made of, for example, a lead zirconate titanate piezoelectric material, is polarized in the thickness direction thereof, and has a rectangular shape with the left-right direction in FIG. 1 as the longitudinal direction. Here, the piezoelectric element 11 has a so-called unimorph type structure, but is not limited to this, and has various flexibility such as a monomorph element, a bimorph element, and a multilayer bimorph element. A piezoelectric element can be used. The reinforcing plate 13 is made of metal or resin. A notch 16 is formed on the inner wall surface of the concave support member 15, and the piezoelectric element 11 is supported by being inserted into the notches 16 so that both ends thereof are movable.

  As is widely known, the buckling spring 14 does not deform when an external force smaller than a certain size is applied, and has a property of bending rapidly when an external force exceeding the certain size is applied. For example, it has a dish-like shape and is supported at its outer periphery, and the center part is recessed, or it has an arch shape and is supported at its longitudinal end, and the center part is recessed. Can be used.

  The buckling spring 14 is generally made of metal, and it is widely known that the buckling spring 14 is used as a switch by providing a contact (terminal) on the side where the buckling spring 14 bends (the bottom plate side of the support member 15). Yes. Therefore, when the reinforcing plate 13 is made of metal, the piezoelectric element 11 is sandwiched between a flexible plastic plate or laminated to be insulated from the piezoelectric element 11 and the buckling spring 14. Is preferred. Such a configuration in which the piezoelectric element 11 is sandwiched between plastic plates is preferable from the viewpoint of protecting the piezoelectric element 11 and from the viewpoint of adjusting the bending strength of the piezoelectric element 11.

  In a state where no external force is applied to the piezoelectric element 11, the piezoelectric element 11 is substantially flat and its lower side is in contact with the buckling spring 14. One reason for this configuration is that, for example, in an application where a person pushes the piezoelectric element 11, the feeling when the piezoelectric element 11 contacts the buckling spring 14 is the feeling that the buckling spring 14 is buckled. This is to avoid misunderstanding.

  The structure in which the reinforcing plate 13 of the piezoelectric element 11 is brought into contact with the buckling spring 14 is that when the piezoelectric plate 12 is brought into contact with the buckling spring 14, a large stress is applied to the contact portion and the piezoelectric plate 12 is destroyed. This is to prevent it. In order to easily support the piezoelectric element 11 in such a state, it is the same as the power generation device 20 shown in FIG. 2 later (however, without bending the piezoelectric element 11 as in the power generation device 20). The notch 16 may be formed so that the piezoelectric element 11 is held in a slightly bent state.

  In the power generation apparatus 10 configured as described above, when an external force (pressing force) F acts on the piezoelectric element 11 so as to shift from the state shown in FIG. 1A to the state shown in FIG. When the external force F is large enough to buckle the buckling spring 14, the piezoelectric element 11 is deformed into an arcuate shape and the buckling spring 14 is buckled and deformed as shown in FIG. At this time, since the buckling spring 14 is buckled rapidly, the piezoelectric element 11 is also bent rapidly. As a result, large electric energy is generated in the piezoelectric element 11 and can be taken out.

  As a modification of the power generation apparatus 10, it is conceivable that the piezoelectric plate 12 (or the piezoelectric element 11) is directly attached to the buckling spring 14, but the buckling spring 14 is shown in FIG. As shown in the figure, since the piezoelectric plate 12 is directly attached to the buckling spring 14 because it is deformed into an approximately M shape, the deformation of the piezoelectric element 11 cannot follow the deformation of the buckling spring 14 and is easily broken. Problems arise. On the other hand, in the power generation device 10, the piezoelectric element 11 is only deformed into an arcuate shape, and is not deformed along the shape of the buckling spring 14. Therefore, the durability of the piezoelectric element 11 is good.

  When the external force F applied to the piezoelectric element 11 is removed, that is, when the force acting on the buckling spring 14 becomes smaller than a certain magnitude, the buckling spring 14 instantaneously returns to its original shape. The piezoelectric element 11 also returns from the arcuate shape to the original shape shown in FIG. 1A, or, as in the state shown in FIG. The direction shown in FIG. Thus, even when the buckling spring 14 returns to its original shape, the piezoelectric element 11 bends rapidly, thereby generating a large electrical energy in the piezoelectric element 11 and taking it out.

  As a configuration for returning from the state shown in FIG. 1B to the state shown in FIG. 1A, buttons for applying an external force to the piezoelectric element 11 are attached to the upper side of the piezoelectric element 11, and the buttons are There is a case where the piezoelectric element 11 has a structure that cannot warp upward because it is positioned so as to move within a certain range. When the piezoelectric element 11 is free, after it enters the state shown in FIG. 1C, it is free-vibrated and attenuated, and settles to the state shown in FIG.

  Since the polarity of the voltage generated when the piezoelectric element 11 is bent changes depending on the bending direction of the piezoelectric element 11, electric energy can be extracted from the piezoelectric element 11 using a bridge rectifier circuit. preferable. Thereby, it is possible to prevent a voltage having a reverse polarity from being applied to a load, a storage battery, or the like.

  Next, a power generator as another embodiment of the present invention will be described. FIG. 2 is a cross-sectional view illustrating a schematic structure of the power generation device 20. In this power generation device 20, a constant force is applied in the longitudinal direction of the piezoelectric element 11, and the piezoelectric element 11 is held in a bent state so as to be convex upward, and the buckling spring 14 is held on the lower surface of the piezoelectric element 11. It has a structure in contact with.

  The bending form of the piezoelectric element 11 and the buckling form of the buckling spring 14 in the power generation apparatus 20 are the same as those of the power generation apparatus 10, but a certain force is applied in the longitudinal direction of the piezoelectric element 11 as in the power generation apparatus 20. In the structure in which the element 11 is held in a bent state, when a pressing force F is applied to the piezoelectric element 11, the piezoelectric element 11 utilizes the spring property of the piezoelectric element 11 itself in addition to the deformation of the buckling spring 14. Can cause steep bending deformation. Further, even when the pressing force F applied to the piezoelectric element 11 is removed, the piezoelectric element is sharpened to the original posture by utilizing the spring property of the piezoelectric element 11 itself in addition to the force received from the buckling spring 14. It is easy to return. By bending the piezoelectric element 11 in this way, high power generation efficiency can be obtained.

  In the power generators 10 and 20 shown in FIGS. 1 and 2, when the light emitting diode is attached to the piezoelectric element 11 via the bridge rectifier circuit, the buckling spring that is buckled and the buckling spring 14 are buckled. It was confirmed that the light emitting diode shines best at the same time as the “click” sound generated when 14 returns to its original posture.

  FIG. 3 is a cross-sectional view showing a schematic structure of a power generator 30 which is still another embodiment of the present invention. In this power generation device 30, one end of the piezoelectric element 11 is fixed to a holding member 31 having a substantially L-shaped cross section, and the other end is a free end. The lower surface of the piezoelectric element 11 is in contact with the buckling spring 14. As shown in FIG. 4, the piezoelectric element 11 is held by fixing a cylindrical member 34 to one end of the piezoelectric element 11 and providing a cylindrical hole 33 in the holding member 31. It is also preferable to have a structure in which the cylindrical member 34 is fitted in the hole 33 so as to be rotatable. Such a method of holding the piezoelectric element 11 shown in FIG. 4 can also be applied to the power generation apparatuses 10 and 20 described above.

  The power generation device 30 can also generate power by the piezoelectric element 11 to cause the light emitting diode to emit light, and when the light emitting diode shines best, it has been confirmed that it is the time of generation of sound accompanying deformation of the buckling spring 14, The power generation process is considered to differ depending on the strength of the piezoelectric element 11.

  That is, when a piezoelectric element having high bending strength is used, the state shown in FIG. 3C is changed from the state shown in FIG. 3A to the state shown in FIG. 3B. In other words, the buckling spring 14 is buckled with almost no bending of the piezoelectric element 11, and electric energy is generated by bending deformation at that time. The holding member 31 is preferably provided with a stopper 32 for limiting the movement of the free end of the piezoelectric element 11 so as not to bend the piezoelectric element 11 excessively.

  If the bending strength of the piezoelectric element 11 and the force causing the buckling spring 14 to buckle are balanced, the piezoelectric element 11 bends along the shape of the buckling spring 14 as shown in FIG. After the deformation, the buckling spring 14 is buckled. In this case, since the amount of deformation of the piezoelectric element 11 is increased, larger electric energy can be obtained.

  If the piezoelectric device 11 having a very low bending strength is used in the power generation device 30, the buckling spring 14 cannot be buckled when an external force F acts on the free end side of the piezoelectric device 11. Since the piezoelectric element 11 is only bent, a large electric energy cannot be obtained unless the piezoelectric element 11 is bent sharply by the external force F. However, in the power generation apparatuses 10 and 20 described above, it is not preferable to apply to the power generation apparatus 30, and the use of a piezoelectric element having a low bending strength has no adverse effect.

  The present invention is suitable for portable electronic devices such as a mobile phone, a portable game machine, and a notebook personal computer. Moreover, it is not limited to such a use, It is suitable as an on-site power generation device of the place where a vibration generate | occur | produces by natural force or human equipment.

Sectional drawing showing the schematic structure and operation | movement state of an electric power generating apparatus. Sectional drawing showing the schematic structure and operation | movement state of another electric power generating apparatus. Furthermore, sectional drawing showing the schematic structure and operation state of another electric power generating apparatus. Sectional drawing which shows another holding form of a piezoelectric element.

Explanation of symbols

10, 20, 30; power generation device 11; piezoelectric element 12; piezoelectric plate 13; reinforcing plate 14; buckling spring 15; support member 16; notch 31; holding member 32; stopper 33;

Claims (4)

A piezoelectric element having flexibility, a support member that flexibly supports the piezoelectric element, and a buckling spring;
When the buckling spring is buckled by applying an external force to the piezoelectric element and the buckling spring is buckled by the piezoelectric element, and the external force applied to the piezoelectric element is removed, the buckling is performed. A power generator characterized by bending and generating electric power when the spring returns to its original shape.   The power generation device according to claim 1, wherein the piezoelectric element is in contact with the buckling spring in a state where an external force is not applied to the piezoelectric element.   3. The power generation device according to claim 1, wherein the piezoelectric element has a rectangular shape, and one end or both ends in the longitudinal direction thereof are supported by the support member.   The piezoelectric element has a rectangular shape, and both ends in the longitudinal direction are supported by the support member in a state in which the piezoelectric element is bent by applying a constant force in the longitudinal direction. The power generation device according to claim 2.

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