JP6987414B2 - Power generation element - Google Patents

Description

The present invention relates to a power generation element, and more particularly to a technique for generating power by converting vibration energy into electrical energy.

In order to make effective use of limited resources, technologies for converting various forms of energy into electrical energy and extracting it have been proposed. One of them is a technique of converting vibration energy into electrical energy and extracting it. For example, in Patent Document 1 below, layered piezoelectric elements are laminated to form a piezoelectric element for power generation, and the piezoelectric element for power generation is used as an external force. A piezoelectric type power generation element that vibrates and generates power is disclosed. Further, Patent Document 2 discloses a power generation element having a MEMS (Micro Electro Mechanical System) structure using a silicon substrate.

The basic principle of these power generation elements is that the vibration of the weight body causes periodic bending of the piezoelectric element, and the electric charge generated based on the stress applied to the piezoelectric element is taken out to the outside. If such a power generation element is mounted on, for example, an automobile, a train, a ship, or the like, it becomes possible to extract the vibration energy applied during transportation as electric energy. It can also be attached to a vibration source such as a refrigerator or an air conditioner to generate electricity.

Japanese Unexamined Patent Publication No. 10-243667 Japanese Unexamined Patent Publication No. 2011-152010

The general power generation element proposed conventionally adopts a structure in which the weight body is supported by a cantilever with one end fixed, and the vertical vibration of the weight body causes periodic bending of the bridge portion. A method is adopted in which the deflection is transmitted to the piezoelectric element to generate an electric charge. In such a method, it is difficult to obtain sufficient power generation efficiency because only vibration energy that vibrates the weight body in the vertical direction can be used.

For example, in transportation equipment such as automobiles, trains, and ships, forces are applied from random directions during operation, so in the case of power generation elements mounted on such transportation equipment, various directional components are added to the vibration of the weight body. Will be included. However, in the above-mentioned conventional power generation element, since only a specific uniaxial direction component can be used for conversion among these vibration energies, the conversion efficiency to electric energy is poor, and it is difficult to improve the power generation efficiency. be.

Therefore, an object of the present invention is to provide a power generation element capable of obtaining high power generation efficiency by converting vibration energy including various directional components into electric energy without waste.

(1) The first aspect of the present invention is in a power generation element that generates power by converting vibration energy into electrical energy.
A plate-shaped bridge that extends along a predetermined longitudinal axis and has flexibility,
A weight body connected to one end of the plate-shaped bridge,
A device housing that houses a plate-shaped bridge and a weight body,
A fixing part that fixes the other end of the plate-shaped bridge part to the device housing,
The lower layer electrodes formed in layers on the surface of the plate-shaped bridge,
A group of upper layer electrodes consisting of a piezoelectric element formed in layers on the surface of the lower layer electrode and a plurality of upper layer electrodes locally formed on the surface of the piezoelectric element.
A power generation circuit that rectifies the current generated based on the electric charge generated in the upper and lower electrodes and extracts power.
And
When an external force that vibrates the device housing is applied, the weight body is configured to vibrate inside the device housing due to the bending of the plate-shaped bridge.
Piezoelectric elements have the property of causing polarization in the thickness direction due to the action of stress that expands and contracts in the layer direction.
The upper layer electrode group has two types of upper layer electrodes, a right side electrode and a left side electrode, and each of these upper layer electrodes is arranged so as to extend along the longitudinal axis, and a predetermined lower layer electrode sandwiches a piezoelectric element. Facing the area,
When the center line along the longitudinal axis is defined for the plate-shaped bridge, the right armpit electrode is placed on one side of the center line, and the left armpit electrode is placed on the other side of the center line. It is what was done.

(2) The second aspect of the present invention is the power generation element according to the first aspect described above.
The lower layer electrode is formed on the upper surface of the plate-shaped bridge portion, the piezoelectric element is formed on the upper surface of the lower layer electrode, and the right side electrode and the left side electrode are formed on the upper surface of the plate-shaped bridge portion via the lower layer electrode and the piezoelectric element. It is what was done.

(3) A third aspect of the present invention is the power generation element according to the first aspect described above.
A lower layer electrode is formed on the side surface as well as the upper surface of the plate-shaped bridge portion, and a piezoelectric element is formed on the surface of this lower layer electrode.
The right armpit electrode and the left armpit electrode are formed on the side surface of the plate-shaped bridge portion via a lower layer electrode and a piezoelectric element.

(4) The fourth aspect of the present invention is the power generation element according to the first aspect described above.
A lower layer electrode is formed on the side surface as well as the upper surface of the plate-shaped bridge portion, and a piezoelectric element is formed on the surface of this lower layer electrode.
The right armpit electrode and the left armpit electrode are formed from the upper surface to the side surface of the plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.

(5) A fifth aspect of the present invention is the power generation element according to the first to fourth aspects described above.
The upper layer electrode group is a group of electrodes on the weight body side arranged in the vicinity of the connection portion of the plate-shaped bridge portion with the weight body, and a group of electrodes on the fixed portion side arranged in the vicinity of the connection portion between the fixed portion of the plate-shaped bridge portion. And have
Each of the weight body side electrode group and the fixed portion side electrode group has two types of upper layer electrodes, a right armpit electrode and a left armpit electrode.

(6) A sixth aspect of the present invention is the power generation element according to the first aspect described above.
The upper layer electrode group has a total of three types of upper layer electrodes, which are the right armpit electrode and the left armpit electrode plus the central electrode.
Each of these upper layer electrodes is arranged so as to extend along the longitudinal axis of the plate-shaped bridge portion, and faces a predetermined region of the lower layer electrode with the piezoelectric element interposed therebetween.
The center electrode is located at the position of the center line along the longitudinal axis of the plate-shaped bridge, the right armpit electrode is located on one side of the center electrode, and the left armpit electrode is the center electrode. It is designed to be placed on the side of the other side.

(7) A seventh aspect of the present invention is the power generation element according to the sixth aspect described above.
The lower layer electrode is formed on the upper surface of the plate-shaped bridge portion, the piezoelectric element is formed on the upper surface of the lower layer electrode, and the center electrode, the right side electrode and the left side electrode form the lower layer electrode and the piezoelectric element on the upper surface of the plate-shaped bridge portion. It is made to be formed through.

(8) The eighth aspect of the present invention is the power generation element according to the sixth aspect described above.
A lower layer electrode is formed on the side surface as well as the upper surface of the plate-shaped bridge portion, and a piezoelectric element is formed on the surface of this lower layer electrode.
The central electrode is formed on the upper surface of the plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.
The right armpit electrode and the left armpit electrode are formed on the side surface of the plate-shaped bridge portion via a lower layer electrode and a piezoelectric element.

(9) A ninth aspect of the present invention is the power generation element according to the sixth aspect described above.
A lower layer electrode is formed on the side surface as well as the upper surface of the plate-shaped bridge portion, and a piezoelectric element is formed on the surface of this lower layer electrode.
The central electrode is formed on the upper surface of the plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.
The right armpit electrode and the left armpit electrode are formed from the upper surface to the side surface of the plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.

(10) In the tenth aspect of the present invention, in the power generation element according to the sixth to ninth aspects described above, the upper layer electrode group is arranged in the vicinity of the connection portion of the plate-shaped bridge portion with the weight body. It has a group of electrodes on the weight side and a group of electrodes on the fixed portion arranged in the vicinity of the connecting portion with the fixed portion of the plate-shaped bridge portion.
Each of the weight body side electrode group and the fixed portion side electrode group has three types of upper layer electrodes, a center electrode, a right armpit electrode, and a left armpit electrode.

(11) An eleventh aspect of the present invention is a power generation element that generates power by converting vibration energy in each coordinate axis direction into electrical energy in the XYZ three-dimensional coordinate system.
A first plate-shaped bridge portion extending along a first longitudinal axis parallel to the Y axis and having flexibility, and a first plate-shaped bridge portion.
A second plate-shaped bridge that is directly or indirectly connected to the first plate-shaped bridge and extends along a second longitudinal axis parallel to the X-axis and has flexibility.
With a weight body directly or indirectly connected to the second plate-shaped bridge,
A device housing for accommodating a first plate-shaped bridge portion, a second plate-shaped bridge portion, and a weight body,
A fixing part that fixes one end of the first plate-shaped bridge part to the device housing,
The lower layer electrodes formed in layers on the surfaces of the first plate-shaped bridge portion and the second plate-shaped bridge portion, and
A group of upper layer electrodes consisting of a piezoelectric element formed in layers on the surface of the lower layer electrode and a plurality of upper layer electrodes locally formed on the surface of the piezoelectric element.
A power generation circuit that rectifies the current generated based on the electric charge generated in the upper and lower electrodes and extracts power.
And
In the fixing portion, the root end portion of the first plate-shaped bridge portion is fixed to the device housing, and the tip portion of the first plate-shaped bridge portion is directly or indirectly connected to the root end portion of the second plate-shaped bridge portion. The weight is directly or indirectly connected to the tip of the second plate-shaped bridge.
When an external force that vibrates the device housing is applied, the weight body is configured to vibrate in each coordinate axis direction in the device housing due to the bending of the first plate-shaped bridge portion and the second plate-shaped bridge portion.
Piezoelectric elements have the property of causing polarization in the thickness direction due to the action of stress that expands and contracts in the layer direction.
The upper layer electrode group includes a first upper layer electrode group formed on the surface of the first plate-shaped bridge portion via a lower layer electrode and a piezoelectric element, and a lower layer electrode and a piezoelectric element on the surface of the second plate-shaped bridge portion. It has a second upper layer electrode group, which is formed through the electrode.
The first upper layer electrode group has two types of upper layer electrodes, a first right side electrode and a first left side electrode, and each of these upper layer electrodes extends along the first longitudinal axis. Arranged, facing a predetermined area of the lower electrode with the piezoelectric element in between,
When the first center line along the first longitudinal axis is defined in the first plate-shaped bridge portion, the first right armpit electrode is arranged on one side of the first center line. The first left armpit electrode is located on the other side of the first centerline.
The second upper layer electrode group has two types of upper layer electrodes, a second right side electrode and a second left side electrode, and each of these upper layer electrodes extends along the second longitudinal axis. Arranged, facing a predetermined area of the lower electrode with the piezoelectric element in between,
When the second center line along the second longitudinal axis is defined in the second plate-shaped bridge portion, the second right armpit electrode is arranged on one side of the second center line. The second left armpit electrode is arranged on the other side of the second center line.

(12) The twelfth aspect of the present invention is the power generation element according to the eleventh aspect described above.
The tip of the first plate-shaped bridge and the root end of the second plate-shaped bridge so that the first plate-shaped bridge and the second plate-shaped bridge are arranged in an L shape. Is connected via an intermediate connection,
The tip of the second plate-shaped bridge and the corner of the weight are connected via the weight connection so that the weight is placed beside the second plate-shaped bridge. ,
The lower surface of the fixing portion is fixed to the upper surface of the bottom plate of the device housing, and the first plate-shaped bridge portion, the second plate-shaped bridge portion, and the weight body are in a state where no external force acts on the device housing. It is designed to be suspended above the bottom plate.

(13) The thirteenth aspect of the present invention is the power generation element according to the twelfth aspect described above.
The eaves structure portion in which the intermediate connection portion protrudes outward from the side surface of the tip portion of the first plate-shaped bridge portion and the eaves structure portion protruding outward from the side surface of the root end portion of the second plate-shaped bridge portion. Have,
The weight connecting portion has an eaves structure portion protruding outward from the side surface of the tip end portion of the second plate-shaped bridge portion.

(14) The fourteenth aspect of the present invention is the power generation element according to the twelfth or thirteenth aspect described above.
The fixing portion is composed of a plate-shaped member for the fixing portion extending along the longitudinal axis for the fixing portion parallel to the X axis, and the root end portion of the first plate-shaped bridge portion is formed at one end of the plate-shaped member for the fixing portion. Is fixed, and the structure composed of the plate-shaped member for the fixing portion, the first plate-shaped bridge portion, and the second plate-shaped bridge portion has a "U" -shaped projection image on the XY plane. A U-shaped structure is formed so that a plate-shaped weight body is arranged in an internal region surrounded by the U-shaped structure.

(15) The fifteenth aspect of the present invention is the power generation element according to the twelfth or thirteenth aspect described above.
The fixing portion is composed of an annular structure, and the first plate-shaped bridge portion, the second plate-shaped bridge portion, and the weight body are arranged in the internal region surrounded by the annular structure. It was done.

(16) The sixteenth aspect of the present invention is the power generation element according to the fifteenth aspect described above.
The role of the fixed portion and the weight body is reversed, the annular structure that was functioning as the fixed portion in the power generation element is made to function as the weight body, and the plate-like body that is functioning as the weight body in the power generation element. The lower surface of the plate-shaped body was fixed to the upper surface of the bottom plate of the device housing, and the annular structure floated above the bottom plate of the device housing in a state where no external force was applied. It is designed to be suspended in the air.

(17) The seventeenth aspect of the present invention is the power generation element according to the eleventh aspect described above.
A third plate-shaped bridge portion to a K-th plate-shaped bridge portion (however, K ≧ 3) is provided between the second plate-shaped bridge portion and the weight body.
The tip of the i-th plate-shaped bridge (however, 1 ≦ i ≦ K-1) is directly or indirectly connected to the root end of the (i + 1) plate-shaped bridge, and the K-plate-shaped bridge is connected. The tip of the part is directly or indirectly connected to the weight body,
The j-th plate-shaped bridge portion (however, 1 ≦ j ≦ K) extends along the longitudinal axis of j parallel to the Y axis when j is odd, and parallel to the X axis when j is even. It is made to extend along the longitudinal axis of the j-th.

(18) The eighteenth aspect of the present invention is the power generation element according to the seventeenth aspect described above.
The tip of the i-th plate-shaped bridge (however, 1 ≦ i ≦ K-1) and the root end of the (i + 1) plate-shaped bridge are connected via the intermediate connection of the i. , The tip of the K-th plate-shaped bridge and the weight body are connected via the weight connection part.
The i-th intermediate connection portion has an eaves structure portion protruding outward from the side surface of the tip portion of the plate-shaped bridge portion of the i-th plate-shaped bridge portion, and the weight connecting portion is the tip portion of the plate-shaped bridge portion of the K-th plate-shaped bridge portion. It has an eaves structure that protrudes outward from the side surface.

(19) The 19th aspect of the present invention is the power generation element according to the 17th or 18th aspect described above.
The structure from the root end of the first plate-shaped bridge to the tip of the K plate-shaped bridge forms a spiral path, and the weight body is the center surrounded by this spiral path. It is designed to be placed in a position.

(20) A twentieth aspect of the present invention is the power generation element according to the above-mentioned 17th to 19th aspects.
A lower layer electrode, a piezoelectric element, and a group of upper layer electrodes are also provided on the surfaces of the third plate-shaped bridge portion to the Kth plate-shaped bridge portion, and the power generation circuit also generates electric power from the charges generated in these upper layer electrodes and lower layer electrodes. I tried to take it out.

(21) The 21st aspect of the present invention is the power generation element according to the 17th to 20th aspects described above.
The fixed portion is composed of an annular structure, and the first plate-shaped bridge portion to the K plate-shaped bridge portion and the weight body are arranged in the internal region surrounded by the annular structure. It was done.

(22) The 22nd aspect of the present invention is the power generation element according to the 21st aspect described above.
The role of the fixed portion and the weight body is reversed, the annular structure that was functioning as the fixed portion in the power generation element is made to function as the weight body, and the plate-like body that is functioning as the weight body in the power generation element. The lower surface of the plate-shaped body was fixed to the upper surface of the bottom plate of the device housing, and the annular structure floated above the bottom plate of the device housing in a state where no external force was applied. It is designed to be suspended in the air.

(23) The 23rd aspect of the present invention is the power generation element according to the 11th to 22nd aspects described above.
The lower layer electrode is formed on the upper surface of the first plate-shaped bridge portion and the second plate-shaped bridge portion, and the piezoelectric element is formed on the upper surface of the lower layer electrode.
The first right armpit electrode and the first left armpit electrode are formed on the upper surface of the first plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.
The second right armpit electrode and the second left armpit electrode are formed on the upper surface of the second plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.

(24) The 24th aspect of the present invention is the power generation element according to the 11th to 22nd aspects described above.
A lower layer electrode is formed on the side surface together with the upper surface of the first plate-shaped bridge portion and the second plate-shaped bridge portion, and a piezoelectric element is formed on the surface of the lower layer electrode.
The first right armpit electrode and the first left armpit electrode are formed on the side surface of the first plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.
The second right armpit electrode and the second left armpit electrode are formed on the side surface of the second plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.

(25) The 25th aspect of the present invention is the power generation element according to the 11th to 22nd aspects described above.
A lower layer electrode is formed on the side surface together with the upper surface of the first plate-shaped bridge portion and the second plate-shaped bridge portion, and a piezoelectric element is formed on the surface of the lower layer electrode.
The first right armpit electrode and the first left armpit electrode are formed from the upper surface to the side surface of the first plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.
The second right armpit electrode and the second left armpit electrode are formed from the upper surface to the side surface of the second plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.

(26) The 26th aspect of the present invention is the power generation element according to the 11th to 25th aspects described above.
The first upper layer electrode group was arranged in the vicinity of the first root end side electrode group arranged near the root end portion of the first plate-shaped bridge portion and the tip portion of the first plate-shaped bridge portion. It has a first tip side electrode group and
The second upper layer electrode group was arranged in the vicinity of the tip portion of the second plate-shaped bridge portion and the second root end portion side electrode group arranged in the vicinity of the root end portion of the second plate-shaped bridge portion. It has a second tip side electrode group and
The first root end side electrode group, the first tip side electrode group, the second root end side electrode group, and the second tip side electrode group are the right side electrode and the left side electrode, respectively. It is designed to have a kind of upper layer electrode.

(27) The 27th aspect of the present invention is the power generation element according to the 11th to 22nd aspects described above.
The first upper layer electrode group has a total of three types of upper layer electrodes, which are the first right armpit electrode and the first left armpit electrode plus the first central electrode.
Each of the upper layer electrodes constituting the first upper layer electrode group is arranged so as to extend along the first longitudinal axis, and faces a predetermined region of the lower layer electrode with the piezoelectric element interposed therebetween.
The first central electrode is arranged at the position of the center line along the first longitudinal axis of the first plate-shaped bridge portion, and the first right armpit electrode is one of the first central electrodes. It is located on the side and the first left armpit electrode is located on the other side of the first center electrode.
The second upper layer electrode group has a total of three types of upper layer electrodes, which are the second right armpit electrode and the second left armpit electrode plus the second central electrode.
Each of the upper layer electrodes constituting the second upper layer electrode group is arranged so as to extend along the second longitudinal axis, and faces a predetermined region of the lower layer electrode with the piezoelectric element interposed therebetween.
The second central electrode is arranged at the position of the center line along the second longitudinal axis of the second plate-shaped bridge portion, and the second right armpit electrode is one of the second central electrodes. It is arranged on the side, and the second left armpit electrode is arranged so as to be arranged on the other side of the second center electrode.

(28) The 28th aspect of the present invention is the power generation element according to the 27th aspect described above.
The lower layer electrode is formed on the upper surface of the first plate-shaped bridge portion and the second plate-shaped bridge portion, and the piezoelectric element is formed on the upper surface of the lower layer electrode.
The first center electrode, the first right armpit electrode, and the first left armpit electrode are formed on the upper surface of the first plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.
The second center electrode, the second right armpit electrode, and the second left armpit electrode are formed on the upper surface of the second plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.

(29) The 29th aspect of the present invention is the power generation element according to the 27th aspect described above.
A lower layer electrode is formed on the side surface together with the upper surface of the first plate-shaped bridge portion and the second plate-shaped bridge portion, and a piezoelectric element is formed on the surface of the lower layer electrode.
The first right armpit electrode and the first left armpit electrode are formed on the side surface of the first plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.
The first central electrode is formed on the upper surface of the first plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.
The second right armpit electrode and the second left armpit electrode are formed on the side surface of the second plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.
The second central electrode is formed on the upper surface of the second plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.

(30) The thirtieth aspect of the present invention is the power generation element according to the twenty-seventh aspect described above.
A lower layer electrode is formed on the side surface together with the upper surface of the first plate-shaped bridge portion and the second plate-shaped bridge portion, and a piezoelectric element is formed on the surface of the lower layer electrode.
The first right armpit electrode and the first left armpit electrode are formed from the upper surface to the side surface of the first plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.
The first central electrode is formed on the upper surface of the first plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.
The second right armpit electrode and the second left armpit electrode are formed from the upper surface to the side surface of the second plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.
The second central electrode is formed on the upper surface of the second plate-shaped bridge portion via the lower layer electrode and the piezoelectric element.

(31) The 31st aspect of the present invention is the power generation element according to the 27th to 30th aspects described above.
The first upper layer electrode group was arranged in the vicinity of the first root end side electrode group arranged near the root end portion of the first plate-shaped bridge portion and the tip portion of the first plate-shaped bridge portion. It has a first tip side electrode group and
The second upper layer electrode group was arranged in the vicinity of the tip portion of the second plate-shaped bridge portion and the second root end portion side electrode group arranged in the vicinity of the root end portion of the second plate-shaped bridge portion. It has a second tip side electrode group and
The first root end side electrode group, the first tip side electrode group, the second root end side electrode group, and the second tip side electrode group are the center electrode, the right side electrode, and the left side, respectively. It has three types of upper layer electrodes, which are electrodes.

(32) A 32nd aspect of the present invention is in a power generation element that generates power by converting vibration energy in each coordinate axis direction into electrical energy in the XYZ three-dimensional coordinate system.
A first plate-shaped bridge portion having flexibility and a second plate-shaped bridge portion having flexibility,
A weight body directly or indirectly connected to both the tip of the first plate-shaped bridge and the tip of the second plate-shaped bridge,
A device housing for accommodating a first plate-shaped bridge portion, a second plate-shaped bridge portion, and a weight body,
A fixing portion for fixing the root end portion of the first plate-shaped bridge portion and the root end portion of the second plate-shaped bridge portion to the device housing, and
The lower layer electrodes formed in layers on the surfaces of the first plate-shaped bridge portion and the second plate-shaped bridge portion, and
Piezoelectric elements formed in layers on the surface of the lower electrode,
A group of upper layer electrodes consisting of a plurality of upper layer electrodes locally formed on the surface of the piezoelectric element,
A power generation circuit that rectifies the current generated based on the electric charge generated in the upper and lower electrodes and extracts power.
And
The root end of the first plate-shaped bridge and the root end of the second plate-shaped bridge are connected to the same starting point of the fixed portion.
The portion near the tip of the first plate-shaped bridge extends in the direction parallel to the X axis, and the portion near the root end of the first plate-shaped bridge extends in the direction parallel to the Y axis. The intermediate portion between the portion near the tip portion and the portion near the root end portion of the plate-shaped bridge portion 1 is curved or bent.
The portion near the tip of the second plate-shaped bridge extends in the direction parallel to the Y axis, and the portion near the root end of the second plate-shaped bridge extends in the direction parallel to the X axis. The intermediate portion between the portion near the tip portion and the portion near the root end portion of the plate-shaped bridge portion of 2 is curved or bent.
When an external force that vibrates the device housing is applied, the weight body is configured to vibrate in each coordinate axis direction in the device housing due to the bending of the first plate-shaped bridge portion and the second plate-shaped bridge portion.
Piezoelectric elements have the property of causing polarization in the thickness direction due to the action of stress that expands and contracts in the layer direction.
The upper layer electrode group includes the first tip side upper layer electrode group formed on the surface of the vicinity of the tip portion of the first plate-shaped bridge portion via the lower layer electrode and the piezoelectric element, and the first plate-shaped bridge portion. The first root end side upper layer electrode group formed on the surface near the root end via the lower electrode and the piezoelectric element, and the lower layer electrode and piezoelectric on the surface near the tip of the second plate-shaped bridge. The second tip side upper layer electrode group formed via the element and the second root end formed via the lower layer electrode and the piezoelectric element on the surface of the portion near the root end of the second plate-shaped bridge portion. It has a group of upper layer electrodes on the part side, and
The first tip side upper layer electrode group has two types of upper layer electrodes, a first tip side right side electrode and a first tip side left side electrode, and each of these upper layer electrodes is in the X-axis direction. The center of the first tip side parallel to the X-axis in the vicinity of the tip of the first plate-shaped bridge, which is arranged so as to extend along the When the line is defined, the first tip side right side electrode is arranged on one side of the first tip side center line, and the first tip side left side electrode is the first tip side. It is located on the other side of the side center line and
The first root end side upper layer electrode group has two types of upper layer electrodes, a first root end side right side electrode and a first root end side left side electrode, and each of these upper layer electrodes is The first plate-like bridge is arranged so as to extend along the Y-axis direction, faces a predetermined region of the lower electrode with a piezoelectric element sandwiched between the electrodes, and is parallel to the Y-axis in the vicinity of the root end of the first plate-shaped bridge portion. When the root end side center line is defined, the first root end side right side electrode is located on one side of the first root end side center line, and the first root end side left side. The side electrode is located on the other side of the first root end side center line.
The second tip side upper layer electrode group has two types of upper layer electrodes, a second tip side right side electrode and a second tip side left side electrode, and each of these upper layer electrodes is in the Y-axis direction. The center of the second tip side parallel to the Y axis in the vicinity of the tip of the second plate-shaped bridge, which is arranged so as to extend along the When the line is defined, the second tip side right side electrode is located on one side of the second tip side center line, and the second tip side left side electrode is the second tip side. It is located on the other side of the side center line and
The second root end side upper layer electrode group has two types of upper layer electrodes, a second root end side right side electrode and a second root end side left side electrode, and each of these upper layer electrodes is A second plate-like bridge that is arranged so as to extend along the X-axis direction, faces a predetermined region of the lower electrode with a piezoelectric element in between, and is parallel to the X-axis in a portion near the root end of the second plate-shaped bridge portion. When the root end side center line is defined, the second root end side right side electrode is located on one side of the second root end side center line, and the second root end side left side. The side electrode is arranged on the other side of the second root end side center line.

(33) The 33rd aspect of the present invention is the power generation element according to the 32nd aspect described above.
It has an intermediate connection portion connected to both the tip portion of the first plate-shaped bridge portion and the tip portion of the second plate-shaped bridge portion, and the weight body is connected to the intermediate connection portion.
The lower surface of the fixing portion is fixed to the upper surface of the bottom plate of the apparatus housing, and the first plate-shaped bridge portion, the second plate-shaped bridge portion, the intermediate connecting portion, and the weight body are in a state where no external force acts. It is designed to be suspended in the air above the bottom plate of the device housing.

(34) The 34th aspect of the present invention is the power generation element according to the 33rd aspect described above.
The eaves structure portion in which the intermediate connection portion protrudes to the left and right sides from the side surface of the tip portion of the first plate-shaped bridge portion and the eaves structure portion protruding to the left and right sides from the side surface of the tip portion of the second plate-shaped bridge portion. And have
The eaves structure in which the fixed portion protrudes to the left and right sides from the side surface of the root end portion of the first plate-shaped bridge portion and the eaves structure protruding to the left and right sides from the side surface of the root end portion of the second plate-shaped bridge portion. It is designed to have a part.

(35) The 35th aspect of the present invention is the power generation element according to the 32nd to 34th aspects described above.
The fixing portion is composed of an annular structure, and a first plate-shaped bridge portion, a second plate-shaped bridge portion and a weight body are arranged in an internal region surrounded by the annular structure, and , The weight body is arranged in the area surrounded by the first plate-shaped bridge portion and the second plate-shaped bridge portion.

(36) The 36th aspect of the present invention is the power generation element according to the 35th aspect described above.
The role of the fixed portion and the weight body is reversed, the annular structure that was functioning as the fixed portion in the power generation element is made to function as the weight body, and the plate-like body that is functioning as the weight body in the power generation element. The lower surface of the plate-shaped body was fixed to the upper surface of the bottom plate of the device housing, and the annular structure floated above the bottom plate of the device housing in a state where no external force was applied. It is designed to be suspended in the air.

(37) The 37th aspect of the present invention is the power generation element according to the 32nd to 36th aspects described above.
The lower layer electrode is formed on the upper surface of the first plate-shaped bridge portion and the second plate-shaped bridge portion, and the piezoelectric element is formed on the upper surface of the lower layer electrode.
The first tip side right armpit electrode, the first tip side left armpit electrode, the first root end side right armpit electrode, and the first root end side left armpit electrode are the first plate-shaped bridge portion. It is formed on the upper surface of the armpit via a lower layer electrode and a piezoelectric element.
The second tip side right armpit electrode, the second tip side left armpit electrode, the second root end side right armpit electrode, and the second root end side left armpit electrode are the second plate-shaped bridge portion. It is formed on the upper surface of the armpit via a lower layer electrode and a piezoelectric element.

(38) The 38th aspect of the present invention is the power generation element according to the 32nd to 36th aspects described above.
A lower layer electrode is formed on the side surface together with the upper surface of the first plate-shaped bridge portion and the second plate-shaped bridge portion, and a piezoelectric element is formed on the surface of the lower layer electrode.
The first tip side right armpit electrode, the first tip side left armpit electrode, the first root end side right armpit electrode, and the first root end side left armpit electrode are the first plate-shaped bridge portion. It is formed on the side surface of the armpit via a lower layer electrode and a piezoelectric element.
The second tip side right armpit electrode, the second tip side left armpit electrode, the second root end side right armpit electrode, and the second root end side left armpit electrode are the second plate-shaped bridge portion. It is formed on the side surface of the armpit via a lower layer electrode and a piezoelectric element.

(39) The 39th aspect of the present invention is the power generation element according to the 32nd to 36th aspects described above.
A lower layer electrode is formed on the side surface together with the upper surface of the first plate-shaped bridge portion and the second plate-shaped bridge portion, and a piezoelectric element is formed on the surface of the lower layer electrode.
The first tip side right armpit electrode, the first tip side left armpit electrode, the first root end side right armpit electrode, and the first root end side left armpit electrode are the first plate-shaped bridge portion. It is formed from the upper surface to the side surface via the lower layer electrode and the piezoelectric element.
The second tip side right armpit electrode, the second tip side left armpit electrode, the second root end side right armpit electrode, and the second root end side left armpit electrode are the second plate-shaped bridge portion. It is formed from the upper surface to the side surface via a lower layer electrode and a piezoelectric element.

(40) The 40th aspect of the present invention is the power generation element according to the 11th to 39th aspects described above.
The fixed part is provided with a stopper protrusion that protrudes in the direction toward the weight body.
The weight body is provided with a stopper groove for accommodating the tip of the stopper protrusion.
While maintaining a predetermined gap between the outer surface of the tip of the stopper protrusion and the inner surface of the stopper groove, the tip of the stopper protrusion and the stopper groove are in a fitted state.

(41) The 41st aspect of the present invention is the power generation element according to the 11th to 40th aspects described above.
As the XYZ three-dimensional coordinate system, a three-dimensional Cartesian coordinate system in which the X-axis, the Y-axis, and the Z-axis are orthogonal to each other is used.

(42) The 42nd aspect of the present invention is the power generation element according to the 11th to 40th aspects described above.
As the XYZ three-dimensional coordinate system, at least a three-dimensional non-orthogonal coordinate system in which the X-axis and the Y-axis are not orthogonal to each other is used.

(43) The 43rd aspect of the present invention is the power generation element according to the 1st to 42nd aspects described above.
The power generation circuit has a capacitive element, a positive charge rectifying element whose forward direction is from each upper layer electrode toward the positive electrode side of the capacitive element in order to guide the positive charge generated in each upper layer electrode to the positive electrode side of the capacitive element. It has a negative charge rectifying element whose forward direction is from the negative electrode side of the capacitive element toward each upper layer electrode in order to guide the negative charge generated in each upper layer electrode to the negative electrode side of the capacitive element, and converts from vibration energy. The generated electrical energy is smoothed by a capacitive element and supplied.

(44) A 44th aspect of the present invention is in a power generation element that generates power by converting vibration energy into electrical energy.
A flexible bridge that extends along a predetermined longitudinal axis,
A weight body connected to one end of the bridge,
A device housing that houses the bridge and weight,
A fixing part that fixes the other end of the bridge part to the device housing,
Piezoelectric elements fixed in place on the surface of the bridge,
A power generation circuit that rectifies the current generated based on the electric charge generated in the piezoelectric element and extracts electric power is provided.
When an external force that vibrates the device housing is applied, the weight is configured to vibrate inside the device housing due to the bending of the bridge.
The piezoelectric element is arranged on the surface of the bridge at a position where expansion and contraction deformation occurs based on the vibration and is off the center line along the longitudinal axis, and charges are generated based on this expansion and contraction deformation. I tried to do it.

(45) A 45th aspect of the present invention is in a power generation element that generates power by converting vibration energy into electrical energy.
A first bridge section that extends along the first longitudinal axis and has flexibility,
A second bridge portion that is directly or indirectly connected to the first bridge portion, extends along a second longitudinal axis, and has flexibility.
With a weight body directly or indirectly connected to the second bridge part,
A device housing for accommodating a first bridge portion, a second bridge portion, and a weight body, and
A fixing part that fixes one end of the first bridge part to the device housing,
Piezoelectric elements fixed in place on the surfaces of the first bridge and the second bridge,
A power generation circuit that rectifies the current generated based on the electric charge generated in the piezoelectric element and extracts electric power is provided.
In the fixing portion, the root end portion of the first bridge portion is fixed to the device housing, and the tip portion of the first bridge portion is directly or indirectly connected to the root end portion of the second bridge portion, and the second The weight body is directly or indirectly connected to the tip of the bridge part of the bridge.
When an external force that vibrates the device housing is applied, the weight body is configured to vibrate in the device housing due to the bending of the first bridge portion and the second bridge portion.
The piezoelectric element is arranged on the surfaces of the first bridge portion and the second bridge portion at positions where expansion and contraction deformation occurs based on the vibration, and charges are generated based on the expansion and contraction deformation. be.

(46) A 46th aspect of the present invention is in a power generation element that generates power by converting vibration energy into electrical energy.
A first bridge portion having flexibility and a second bridge portion having flexibility,
A weight body directly or indirectly connected to both the tip of the first bridge and the tip of the second bridge,
A device housing for accommodating a first bridge portion, a second bridge portion, and a weight body, and
A fixing portion for fixing the root end portion of the first bridge portion and the root end portion of the second bridge portion to the device housing, and a fixing portion.
Piezoelectric elements fixed in place on the surfaces of the first bridge and the second bridge,
A power generation circuit that rectifies the current generated based on the electric charge generated in the piezoelectric element and extracts electric power is provided.
The root end of the first bridge portion and the root end portion of the second bridge portion are connected to the same starting point portion of the fixed portion, and the vicinity of the tip portion and the vicinity of the root end portion of the first bridge portion. The intermediate portion between the portions is curved or bent, and the intermediate portion between the portion near the tip of the second bridge portion and the portion near the root end is curved or bent.
When an external force that vibrates the device housing is applied, the weight body is configured to vibrate in the device housing due to the bending of the first bridge portion and the second bridge portion.
The piezoelectric element is arranged on the surfaces of the first bridge portion and the second bridge portion at positions where expansion and contraction deformation occurs based on the vibration, and charges are generated based on the expansion and contraction deformation. be.

(47) The 47th aspect of the present invention constitutes a power generation device in which a plurality of sets of power generation elements according to the 41st aspect described above are provided and the electric power taken out by each power generation element is supplied to the outside. ..

(48) The 48th aspect of the present invention is the power generation device according to the 47th aspect described above.
The X-axis direction, the Y-axis direction, or both of some power generation elements are arranged in a direction different from these directions in another part of the power generation element.

(49) The 49th aspect of the present invention is the power generation device according to the 48th aspect described above.
Having four sets of power generation elements, the second power generation element is arranged in a direction in which the Y-axis direction is reversed when the X-axis direction and the Y-axis direction of the first power generation element are used as a reference, and the third power generation element is generated. The elements are arranged in a direction in which the X-axis direction is reversed, and the fourth power generation element is arranged in a direction in which both the X-axis direction and the Y-axis direction are reversed.

(50) The 50th aspect of the present invention is the power generation device according to the 47th to 49th aspects described above.
The weights of the plurality of power generation elements have different resonance frequencies.

(51) The 51st aspect of the present invention is the power generation device according to the 50th aspect described above.
By setting the areas of the projected images of the weights on the XY plane to be different from each other, the thicknesses in the Z-axis direction to be different from each other, or both of them, a plurality of power generation elements can be generated. The mass of the weight body is different.

(52) The 52nd aspect of the present invention is the power generation device according to the 50th or 51st aspect described above.
For the first plate-shaped bridge portion and / or the second plate-shaped bridge portion of the plurality of power generation elements, the areas of the projected images on the XY plane are set to be different from each other, or the thicknesses in the Z-axis direction are different from each other. By setting such as, or by setting both of them, the resonance frequencies of the weights of the plurality of power generation elements are made different.

The power generation element according to the present invention adopts a structure in which one end of a plate-shaped bridge portion constituting a cantilever is fixed and a weight body is connected to the other end, and the plate-shaped bridge portion is subjected to horizontal vibration energy and horizontal direction. Since the vibration energy of the above can be used, the vibration energy can be converted into electric energy without waste, and high power generation efficiency can be obtained.

In particular, in the basic embodiment of the power generation element according to the present invention, a layered piezoelectric element is formed on a plate-shaped bridge portion constituting a cantilever, and a center electrode, a right side electrode, and a left side electrode are formed on the surface thereof. Some of the three types of upper layer electrodes are locally formed. Here, since the central electrode is arranged at the position of the center line along the longitudinal axis on the upper surface side of the plate-shaped bridge portion, the electric charge is efficiently applied according to the vertical deflection of the plate-shaped bridge portion. Can be generated. On the other hand, since the right side electrode and the left side electrode are arranged on both sides of the central electrode, electric charges can be efficiently generated according to the vertical deflection of the plate-shaped bridge portion, and the plate-shaped bridge is formed. Charges can be efficiently generated according to the horizontal deflection of the bridge portion. Therefore, vibration energy including both vertical and horizontal components can be converted into electrical energy without waste, and high power generation efficiency can be obtained.

Further, in the XYZ three-dimensional coordinate system, a first plate-shaped bridge portion arranged along the direction parallel to the Y axis and a second plate-shaped bridge portion arranged along the direction parallel to the X axis. According to the embodiment using, the vibration energy in the X-axis direction, the Y-axis direction, and the Z-axis direction is converted into electric energy by the right side electrode and the left side electrode formed in the first and second plate-shaped bridge portions. Further, if the central electrodes formed on the first and second plate-shaped bridge portions are provided, the vibration energy in the Z-axis direction can be converted into electric energy. Therefore, the vibration energy including the components in all the coordinate axis directions in the XYZ three-dimensional coordinate system can be converted into electric energy without waste, and higher power generation efficiency can be obtained.

It is a top view (FIG. (a)) and a side view (FIG. (b)) of the basic structure constituting the power generation element which concerns on 1st Embodiment of this invention. A plan view (FIG. (A)) showing a state when the weight body 30 of the basic structure shown in FIG. 1 causes a displacement Δx (+) in the positive direction of the X-axis and a displacement Δz (+) in the positive direction of the Z-axis. It is a side view (Fig. (B)) showing the state when the above occurs. It is a plan view (FIG. (a)) of the power generation element which concerns on 1st Embodiment of this invention, and is the side sectional view (FIG. (b)) which cut it in the YZ plane. FIG. 3 is a table showing the polarities of charges generated in the upper layer electrodes E11 to E23 when the weight body 30 of the power generation element shown in FIG. 3 is displaced in each coordinate axis direction. It is a circuit diagram which shows the specific structure of the power generation circuit 60 used for the power generation element shown in FIG. It is a top view which shows the modification of the power generation element shown in FIG. It is a table which shows the polarity of the charge generated in each upper layer electrode E31 to E33 when the weight body 30 of the power generation element shown in FIG. 6 is displaced in each coordinate axis direction. It is a normal cross-sectional view which shows the variation of the arrangement mode of the upper layer electrode in the power generation element which concerns on this invention. It is a plan view (FIG. (a)) of the basic structure 100 which constitutes the power generation element which concerns on 2nd Embodiment of this invention, and is the side sectional view (FIG. (b)) which cut it in the YZ plane. It is a plan view (FIG. (a)) of the power generation element which concerns on 2nd Embodiment of this invention, and is the side sectional view (FIG. (b)) which cut it in the YZ plane. FIG. 9 is a plan view showing a stretched state of each upper layer electrode forming position when the weight body 150 of the basic structure 100 shown in FIG. 9 causes a displacement Δx (+) in the positive direction of the X axis. FIG. 9 is a plan view showing a stretched state of each upper layer electrode forming position when the weight body 150 of the basic structure 100 shown in FIG. 9 causes a displacement Δy (+) in the positive direction of the Y axis. FIG. 9 is a plan view showing a stretched state of each upper layer electrode forming position when the weight body 150 of the basic structure 100 shown in FIG. 9 causes a displacement Δz (+) in the positive direction of the Z axis. It is a table which shows the polarity of the charge generated in each upper layer electrode Ex1 to Ez4 when the weight body 150 of the power generation element shown in FIG. 10 is displaced in each coordinate axis direction. It is a circuit diagram which shows the specific structure of the power generation circuit 500 used for the power generation element shown in FIG. It is a top view which shows the structure of the basic structure of the power generation apparatus which used 4 sets of power generation elements shown in FIG. 10 (the part inside the structure is hatched in order to clearly show the plan shape). It is a top view which shows the structure of the basic structure of the power generation device which concerns on the modification of the power generation device which shows FIG. A plan view showing the structure of the basic structure of the power generation element according to the modified example of the power generation element shown in FIG. It is a side sectional view (FIG. (b)) which cut this in the YZ plane. With respect to the basic structure of the power generation element shown in FIG. 10 (Fig. (A)) and the basic structure of the power generation element shown in FIG. 18 (Fig. (B)), the weight body 150 is displaced in the positive direction of the X-axis Δx (+). It is a stress distribution map which shows the magnitude of the stress generated in each plate-shaped bridge part at the time of occurrence. With respect to the basic structure of the power generation element shown in FIG. 10 (Fig. (A)) and the basic structure of the power generation element shown in FIG. 18 (Fig. (B)), the weight body 150 is displaced in the positive direction of the Y axis Δy (+). It is a stress distribution diagram which shows the magnitude of the stress generated in each plate-shaped bridge part at the time of occurrence. With respect to the basic structure of the power generation element shown in FIG. 10 (Fig. (A)) and the basic structure of the power generation element shown in FIG. 18 (Fig. (B)), the weight body 150 is displaced in the positive direction of the Z axis Δz (+). It is a stress distribution diagram which shows the magnitude of the stress generated in each plate-shaped bridge part at the time of occurrence. A plan view showing the structure of the basic structure of the power generation element according to the modified example of the power generation element shown in FIG. It is a side sectional view (FIG. (b)) which cut this in the YZ plane. It is a top view which shows the structure of the basic structure of the power generation element which concerns on another modification of the power generation element shown in FIG. 18 (in order to clearly show the plane shape, the part inside the structure is hatched). Plan view showing the structure of the basic structure of the power generation element according to still another modification of the power generation element shown in FIG. 18 (FIG. (A): In order to clearly show the plan shape, the inner part of the structure is hatched. (Shown) and a side sectional view (Fig. (B)) of this cut along the YZ plane. A plan view showing the structure of the basic structure of the power generation element according to the modified example of the power generation element shown in FIG. 22 (Fig. (A): In order to clearly show the plan shape, the inner part of the structure is hatched) and It is a side sectional view (FIG. (b)) which cut this in the YZ plane. It is a top view which shows the modification which omitted the central electrode in the embodiment shown in FIG. It is a top view which shows the modification which omitted the central electrode in the embodiment shown in FIG. It is a top view which shows the modification which omitted the central electrode in the embodiment shown in FIG. An example of forming three types of upper layer electrodes, a center electrode, a right armpit electrode, and a left armpit electrode (Fig. (A)), and an example of forming two types of upper layer electrodes, a right armpit electrode and a left armpit electrode (Fig. (B)). ) Is a plan view (hatching is attached to clearly show the electrode shape). It is a top view which shows the modification which adopted the stopper structure for the basic structure shown in FIG. 18 (in order to clearly show the plane shape, the part inside the structure is hatched). It is a top view which shows the modification which adopted the two-arm support type for the basic structure shown in FIG. 18 (in order to clearly show the plane shape, the part inside the structure is hatched). It is a top view which shows the modification which adopted the stopper structure for the basic structure shown in FIG. 31 (in order to clearly show the plane shape, the part inside the structure is hatched). It is a top view which shows the deformation example which deformed the shape of the plate-shaped bridge part of the basic structure shown in FIG. 31 (in order to clearly show the plan shape, the part inside the structure is hatched). FIG. 3 is a plan view showing a modified example in which the Cartesian coordinate system in the power generation element shown in FIG. 10 is changed to a non-Orthogonal coordinate system.

<<< §1. First Embodiment (2-axis power generation type) >>>
FIG. 1 is a plan view (upper view (a)) and a side view (lower view (b)) of a basic structure constituting the power generation element according to the first embodiment of the present invention. As shown in FIG. 1 (a), this basic structure is composed of a fixing portion 10, a plate-shaped bridge portion 20, and a weight body 30. The side view of FIG. 1B shows a state in which the lower surface of the fixing portion 10 is fixed to the upper surface of the bottom plate 40 of the apparatus housing. For the sake of convenience, detailed illustration of the device housing is omitted here, and in FIG. 1B, only a part of the bottom plate 40 is hatched, but in reality, the entire basic structure is shown. A device housing is provided to accommodate it.

The left end of the plate-shaped bridge portion 20 is fixed by the fixing portion 10, and the weight body 30 is connected to the right end. The plate-shaped bridge portion 20 functions as a cantilever and serves to hold the weight body 30 in a suspended state above the bottom plate 40 of the apparatus housing. Hereinafter, the end of the plate-shaped bridge portion 20 on the fixed portion 10 side (left end in the figure) will be referred to as a root end portion, and the end on the weight body 30 side (right end in the figure) will be referred to as a tip portion.

Since the plate-shaped bridge portion 20 has flexibility, bending occurs due to the action of an external force. Therefore, when vibration is applied to the device housing from the outside, a force is applied to the weight body 30 by the vibration energy, and this force acts on the tip portion of the plate-shaped bridge portion 20. Since the root end portion of the plate-shaped bridge portion 20 is fixed, the plate-shaped bridge portion 20 is bent, and the weight body 30 vibrates in the apparatus housing.

Here, for convenience of explaining the vibration direction, the origin O is set at the position of the center of gravity of the weight body 30 in a state where the device housing is stationary, and the XYZ three-dimensional coordinate system is defined as shown in the figure. That is, in the plan view of FIG. 1A, the X-axis is defined in the lower part of the figure, the Y-axis is defined in the right side of the figure, and the Z-axis is defined in the vertical upper part of the paper surface. In the side view of FIG. 1 (b), the Z axis is defined in the upper part of the figure, the Y axis is defined in the right side of the figure, and the X axis is defined in the vertical upper part of the paper surface. In each of the subsequent figures in the present application, each coordinate axis is defined in the same direction.

Further, for convenience of explanation, it is assumed that the device housing is attached to a vibration source (for example, a vehicle) so that the XY plane of the above-mentioned three-dimensional coordinate system becomes a horizontal plane and the Z axis becomes a vertical axis. .. Therefore, in the present application, with respect to the basic structure, the term "up" generally means the Z-axis positive direction, and the term "down" generally means the Z-axis negative direction (of course, "upper part of the figure"). "And" the bottom of the figure "means the top and bottom of the figure).

FIG. 2A is a plane showing a deformed state when the weight body 30 causes a displacement Δx (+) in the positive direction of the X-axis with respect to the position of the fixed portion 10 in the basic structure shown in FIG. It is a figure. Such a displacement occurs when an acceleration in the positive direction of the X-axis acts on the weight body 30. Since the weight body 30 is displaced downward in the figure, the upper side in the figure of the plate-shaped bridge portion 20 extends in the Y-axis direction, and the lower side in the figure of the plate-shaped bridge portion 20 contracts in the Y-axis direction. In other words, the upper part in the figure extends in the Y-axis direction from the center line shown by the broken line in the figure, and the lower part in the figure shrinks in the Y-axis direction. In the figure of the present application, for convenience, the symbol "+" is described in the extending portion and the symbol "-" is described in the contracting portion in a small circle.

FIG. 2A shows a state when a displacement Δx (+) in the positive direction of the X-axis occurs, but when a displacement Δx (−) in the negative direction of the X-axis occurs, the weight body 30 is shown in FIG. The expansion and contraction state of each part of the plate-shaped bridge portion 20 is the reverse of the state shown in FIG. 2 (a). Therefore, when vibration energy having a vibration component in the X-axis direction is applied to the device housing, the shape of the basic structure is deformed while alternately repeating the state shown in FIG. 2 (a) and its inverted state. However, the weight body 30 vibrates in the X-axis direction (horizontal direction) in the device housing.

On the other hand, FIG. 2B shows the deformed state of the basic structure shown in FIG. 1 when the weight body 30 causes a displacement Δz (+) in the positive direction of the Z axis with respect to the position of the fixed portion 10. It is a side view which shows. Such a displacement occurs when an acceleration in the positive direction of the Z axis acts on the weight body 30. Since the weight body 30 is displaced upward in the figure, the upper surface side in the figure of the plate-shaped bridge portion 20 contracts in the Y-axis direction, and the lower surface side in the figure of the plate-shaped bridge portion 20 expands in the Y-axis direction. In other words, the upper layer portion of the plate-shaped bridge portion 20 contracts in the Y-axis direction, and the lower layer portion expands in the Y-axis direction.

FIG. 2B shows a state when a displacement Δz (+) in the positive direction of the Z axis occurs, but when a displacement Δz (−) in the negative direction of the Z axis occurs, the weight body 30 is shown in the figure. The expansion and contraction state of each part of the plate-shaped bridge portion 20 is the reverse of the state shown in FIG. 2 (b). Therefore, when vibration energy having a vibration component in the Z-axis direction is applied to the device housing, the shape of the basic structure is deformed while alternately repeating the state shown in FIG. 2 (b) and its inverted state. However, the weight body 30 vibrates in the Z-axis direction (vertical direction) in the apparatus housing.

Here, the illustration of the deformed state when the displacements Δy (+) and Δy (−) in the Y-axis direction occur is omitted. Of course, when the acceleration in the Y-axis direction acts on the weight body 30, the plate-shaped bridge portion 20 expands or contracts in the Y-axis direction as a whole, and the weight body 30 is displaced in the Y-axis direction. It will be. However, when the amount of vibration energy applied is the same, the amount of displacement Δy (+) and Δy (-) in the Y-axis direction is the amount of displacement Δx (+) and Δx (-) in the X-axis direction and the amount in the Z-axis direction. It is smaller than the amount of displacement Δz (+) and Δz (−) of. That is, the amount of expansion and contraction of the plate-shaped bridge portion 20 caused by the vibration energy in the Y-axis direction is smaller than the amount of expansion and contraction of the plate-shaped bridge portion 20 caused by the vibration energy in the X-axis or Z-axis direction.

This is performed by the deformation operation in which the vibration in the X-axis direction and the vibration in the Z-axis direction of the weight body 30 bend the plate-shaped bridge portion 20 in a predetermined direction as shown in FIGS. 2 (a) and 2 (b). On the other hand, it is considered that the vibration in the Y-axis direction is performed by the deformation operation of stretching or compressing the plate-shaped bridge portion 20 as a whole, so that the mechanical deformation efficiency is low.

For this reason, the power generation element according to the first embodiment is designed as a two-axis power generation type element that generates power based on the vibration of the weight body 30 in the X-axis direction and the vibration in the Z-axis direction. Therefore, vibration in the Y-axis direction is not considered. Of course, in reality, power generation is possible even when vibration energy in the Y-axis direction is applied, but the power generation efficiency is considerably lower than when vibration energy in the X-axis or Z-axis direction is added. Become.

In the case of the embodiment shown here, the basic structure including the fixed portion 10, the plate-shaped bridge portion 20, and the weight body 30 is all configured by an integral structure cut out from the silicon substrate. In the case of this embodiment, the plate-shaped bridge portion 20 has a beam structure having a width of 1 mm in the X-axis direction, a length of 4 mm in the Y-axis direction, and a thickness of about 0.5 mm in the Z-axis direction. The weight body 30 has a width of 5 mm in the X-axis direction, a width of 3 mm in the Y-axis direction, and a thickness of 0.5 mm in the Z-axis direction. The width is 2 mm and the thickness in the Z-axis direction is 1 mm.

Of course, the dimensions of each part can be set arbitrarily. In short, the plate-shaped bridge portion 20 may be set to a size suitable for having flexibility that allows deformation as shown in FIG. 2, and the weight body 30 is a plate-shaped bridge due to vibration energy from the outside. The dimensions of the portion 20 may be set to have a sufficient mass to cause the deformation as shown in FIG. 2, and the fixing portion 10 has a dimension that allows the entire basic structure to be firmly fixed to the bottom plate 40 of the apparatus housing. It should be set to.

As shown in FIG. 2B, the thickness of the fixing portion 10 is set to be larger than the thickness of the plate-shaped bridge portion 20 and the weight body 30, and the weight body 30 is suspended in the device housing. Ensure that a space that can vibrate in the vertical direction is secured. As described above, this basic structure will be housed in the device housing, but the inner wall surface of the device housing (for example, the upper surface of the bottom plate 40 shown in FIG. 2B) and the weight body 30 It is preferable to set the clearance dimension between the two to a predetermined value so that the inner wall surface of the apparatus housing functions as a control member that limits the excessive displacement of the weight body 30. By doing so, even if an excessive acceleration (acceleration that damages the plate-shaped bridge portion 20) is applied to the weight body 30, it is possible to limit the excessive displacement of the weight body 30 and the plate-shaped bridge portion. It is possible to avoid a situation in which 20 is damaged. However, if the void size is too narrow, it will be affected by air damping and the power generation efficiency will decrease, so care must be taken.

Although the structure and deformation operation of the basic structure which is a component of the power generation element according to the first embodiment have been described above with reference to FIGS. 1 and 2, the power generation element is further added to this basic structure. , Consists of adding some elements.

FIG. 3A is a plan view of the power generation element according to the first embodiment, and FIG. 3B is a side sectional view of the power generation element cut along a YZ plane. As shown in the side sectional view of FIG. 3 (b), the upper surface of the basic structure (fixed portion 10, plate-shaped bridge portion 20, weight body 30) shown in FIG. 1 (b) has a layered lower layer electrode over the entire surface. E0 is formed, and a layered piezoelectric element 50 is formed on the upper surface thereof over the entire surface. An upper layer electrode group composed of a plurality of locally formed upper layer electrodes is formed on the upper surface of the piezoelectric element 50.

In the case of the examples shown here, as shown in FIG. 3A, the upper layer electrodes are 6 upper layer electrodes E11 to E23 (hatching in the figure is attached to clearly show the electrode forming region. , Does not indicate a cross section). In the side sectional view of FIG. 3B, only the upper layer electrodes E12 and E22 located on the YZ cut surface appear. Since FIG. 3A is a plan view of the power generation element viewed from above, the piezoelectric element 50 covering the entire surface of the basic structure can be seen. However, for convenience, FIG. 3A is shown. The positions of the fixed portion 10, the plate-shaped bridge portion 20, and the weight body 30 are indicated by reference numerals using a broken line leader line.

Here, of the six upper layer electrodes E11 to E23 shown in FIG. 3A, the three electrodes E11, E12, and E13 formed on the weight body 30 side are referred to as a weight body side electrode group. The three electrodes E21, E22, and E23 formed on the fixed portion 10 side will be referred to as a fixed portion side electrode group. Further, regarding the weight body side electrode group, the electrodes E12 arranged in the center are referred to as a center electrode, and the electrodes E11 and E13 arranged on both sides thereof are referred to as a right armpit electrode and a left armpit electrode, respectively. Similarly, regarding the fixed portion side electrode group, the electrode E22 arranged in the center is referred to as a center electrode, and the electrodes E21 and E23 arranged on both sides thereof are referred to as a right armpit electrode and a left armpit electrode, respectively.

The terms "right armpit" and "left armpit" in the present application are used to distinguish the pair of electrodes arranged on both sides of the central electrode from each other, and for convenience, the plate-shaped bridge portion. It means the left and right when the upper surface is viewed from the root end side. Of course, when the upper surface of the plate-shaped bridge is viewed from the tip side, the left and right sides are reversed, but in the present application, the left and right when the upper surface of the plate-shaped bridge is viewed from the root end side are always used as a reference. We will use the words "right armpit" and "left armpit".

In the case of the embodiment shown here, the basic structure (fixing portion 10, plate-shaped bridge portion 20, weight body 30) is composed of a silicon substrate. Further, the lower layer electrodes E0 and the upper layer electrodes E11 to E23 may be formed by using a general conductive material such as metal. In the case of the example shown here, the lower layer electrode E0 and the upper layer electrodes E11 to E23 are formed by a thin film-like metal layer having a thickness of about 300 nm (a metal layer composed of two layers of a titanium film and a platinum film). On the other hand, as the piezoelectric element 50, a thin film of PZT (lead zirconate titanate), KNN (sodium niobate), or the like may be used. In the case of the embodiment shown here, a thin-film piezoelectric element having a thickness of about 2 μm is formed.

As shown in FIG. 3B, this power generation element is further provided with a power generation circuit 60. In FIG. 3B, the power generation circuit 60 is shown as a simple block, but a specific circuit diagram will be described later. As shown in the figure, wiring is provided between the power generation circuit 60 and the lower layer electrodes E0 and the six upper layer electrodes E11 to E23, and the electric charges generated by the upper layer electrodes E11 to E23 are transmitted through the wiring. Is taken out by the power generation circuit 60. In reality, each wiring can be formed by a conductive pattern formed on the upper surface of the piezoelectric element 50 together with the upper layer electrodes E11 to E23. Further, when the basic structure is composed of a silicon substrate, the power generation circuit 60 can be formed on the silicon substrate (for example, a portion of the fixed portion 10).

Although the device housing is not shown in FIG. 3 (the bottom plate 40 shown in FIG. 3B constitutes a part of the device housing), in reality, FIG. 3 (b) The entire structure shown in) is housed in a device housing (not shown).

After all, the power generation element according to the first embodiment is a power generation element having a function of generating power by converting vibration energy into electric energy, and is a predetermined longitudinal axis (Y axis in the case of the illustrated example). ), A flexible plate-shaped bridge portion 20, a weight body 30 connected to one end (tip portion) of the plate-shaped bridge portion 20, and a plate-shaped bridge portion 20 and a weight body 30. The device housing for accommodating the device housing, the fixing portion 10 for fixing the other end (root end portion) of the plate-shaped bridge portion 20 to the device housing (upper surface of the bottom plate 40 in the case of the illustrated example), and the plate-shaped bridge portion 20. The lower layer electrode E0 formed in layers on the surface of the lower layer electrode E0, the piezoelectric element 50 formed in layers on the surface of the lower layer electrode E0, and the plurality of upper layer electrodes E11 to locally formed on the surface of the piezoelectric element 50. It includes an upper layer electrode group composed of E23, and a power generation circuit 60 that rectifies the current generated based on the charges generated in the upper layer electrodes E11 to E23 and the lower layer electrodes E0 to extract electric power.

As described above, in the power generation element having such a structure, when an external force that vibrates the device housing acts, the weight body 30 vibrates in the device housing due to the bending of the plate-shaped bridge portion 20. Then, the bending of the plate-shaped bridge portion 20 is transmitted to the piezoelectric element 50, and the same bending occurs in the piezoelectric element 50. Here, since the piezoelectric element 50 has a property of causing polarization in the thickness direction by the action of stress that expands and contracts in the layer direction, electric charges are generated on the upper surface and the lower surface thereof. The generated charge is taken out from the upper layer electrodes E11 to E23 and the lower layer electrode E0.

In the case of the embodiment shown here, when a stress extending in the layer direction acts, a positive charge is generated on the upper surface side and a negative charge is generated on the lower surface side, and conversely, when a stress contracting in the layer direction acts, a negative charge and a lower surface are generated on the upper surface side. A piezoelectric element 50 that generates a positive charge on the side is used. Of course, some piezoelectric elements have a polarization characteristic completely opposite to this, and the piezoelectric element having any polarization characteristic may be used for the power generation element according to the present invention.

Next, let's look at the specific power generation operation of this power generation element. In the case of the embodiment shown in FIG. 3A, the upper layer electrode group includes the weight body side electrode groups E11 to E13 arranged in the vicinity of the connection portion of the plate-shaped bridge portion 20 with the weight body 30, and the plate-shaped bridge portion. It is divided into the fixed portion side electrode groups E21 to E23 arranged in the vicinity of the connecting portion of the fixed portion 10 of the 20. The weight body side electrode group is composed of three types of electrodes: the center electrode E12, the right side electrode E11, and the left side electrode E13, and the fixed portion side electrode group also includes the center electrode E22, the right side electrode E21, and the left side electrode. It is composed of three types of electrodes called E23.

All of the six upper layer electrodes E11 to E23 are arranged so as to extend along the longitudinal axis (Y axis) of the plate-shaped bridge portion 20, and face a predetermined region of the lower layer electrode E0 with the piezoelectric element 50 interposed therebetween. ing. In other words, the lower layer electrode E0 and the piezoelectric element 50 are common, but since the six upper layer electrodes E11 to E23 are locally and individually arranged, each of the six individual power generators is located. It will be placed in a specific position.

Here, the center electrodes E12 and E22 are located on the upper surface side of the plate-shaped bridge portion 20 at the position of the center line along the longitudinal axis (Y axis) (the position of the line obtained by translating the Y axis to the upper surface of the piezoelectric element 50). ), And is an electrode provided with the intention of efficiently extracting electric charge when the weight body 30 is vibrating in the Z-axis direction.

Further, the right armpit electrode E11 is arranged on one side of the center electrode E12 (right side when viewed from the root end side), and the left armpit electrode E13 is located on the other side of the center electrode E12 (root end). It is located on the left side when viewed from the part side). Similarly, the right armpit electrode E21 is arranged on one side of the center electrode E22 (right side when viewed from the root end side), and the left armpit electrode E23 is located on the other side of the center electrode E22 (root). It is located on the left side when viewed from the end side). Each of these side electrodes is an electrode provided with the intention of efficiently extracting electric charge when the weight body 30 is vibrating in the X-axis direction.

In FIG. 4, in the power generation element shown in FIG. 3, when the lower layer electrode E0 is used as a common electrode and the weight body 30 is displaced in each coordinate axis direction, the charges generated in the upper layer electrodes E11 to E23 and the lower layer electrodes E0 are shown in FIG. It is a table showing the polarity. In the table, the sign "+" indicates the generation of a positive charge, and the sign "-" indicates the generation of a negative charge. Further, the symbol "0" indicates a state in which no electric charge is generated at all, or a small amount of electric charge is generated as compared with the case indicated by the symbol "+" or the symbol "-". Practically, the generated charge in the column corresponding to the symbol "0" is not a significant amount, so it will be ignored in the following description.

When the weight body 30 is displaced in each coordinate axis direction, the plate-shaped bridge portion 20 is bent as shown in FIGS. 2 (a) and 2 (b). On the other hand, as described above, in the piezoelectric element 50, when a stress extending in the layer direction acts, a positive charge is generated on the upper surface side and a negative charge is generated on the lower surface side, and when a stress contracting in the layer direction acts, a negative charge and a lower surface are generated on the upper surface side. It has a polarization characteristic that a positive charge is generated on the side. Based on these points, it can be easily understood that the table shown in FIG. 4 can be obtained.

For example, when a displacement Δx (+) in the positive direction of the X-axis occurs, the deformation as shown in FIG. Negative charges are generated in the side electrodes E11 and E21. On the other hand, the piezoelectric element directly below the left armpit electrodes E13 and E23 extends in the longitudinal direction, and positive charges are generated in the left armpit electrodes E13 and E23. At this time, since the piezoelectric element directly below the center electrodes E12 and E22 arranged on the center line extends and the half body contracts, the generated charges are canceled and no charges are generated in the center electrodes E12 and E22. On the other hand, in the lower layer electrode E0, a charge having the opposite polarity to the charge generated in each upper layer electrode E11, E13, E21, E23 is generated, but the total of the generated charges in each upper layer electrode is 0. Therefore, the generated charge of the lower layer electrode E0 also becomes 0.

Further, when the displacement Δz (+) in the positive direction of the Z axis occurs, the deformation as shown in FIG. 2B occurs, so that all the piezoelectric elements directly under the six upper layer electrodes E11 to E23 are in the longitudinal direction. Shrinks to generate a negative charge on all upper electrodes. On the other hand, in the lower layer electrode E0, a charge (positive charge) having the opposite polarity equal to the sum of the charges (negative charge) generated in each of the upper layer electrodes E11 to E23 is generated. In the table of FIG. 4, the reference numeral “++++++” written in the column of the lower layer electrode E0 in the row of the displacement Δz (+) indicates such a state.

On the other hand, when the displacement Δy (+) in the positive direction of the Y-axis occurs, all the piezoelectric elements directly under the six upper layer electrodes E11 to E23 extend in the longitudinal direction, so that positive charges are generated in all the upper layer electrodes. However, as described above, the amount of displacement Δy (+) in the Y-axis direction when the acceleration in the Y-axis direction acts on the weight body 30 is the amount in the X-axis direction when the acceleration in the X-axis direction acts. Since it is smaller than the amount of the displacement Δx (+) and the amount of the displacement Δz (+) in the Z-axis direction when the acceleration in the Z-axis direction acts, the amount of positive charge generated is also small. Therefore, in the table of FIG. 4, the symbol “0” is indicated in all the columns of Δy (+) to indicate that significant power generation is not performed.

In addition, the table of FIG. 4 shows the electric charge generated by each upper layer electrode when the positive displacement Δx (+), Δy (+), Δz (+) of each coordinate axis occurs with respect to the weight body 30. As shown, when the displacements of each coordinate axis in the negative direction Δx (−), Δy (−), Δz (−) occur, the result of reversing the reference numerals in the table of FIG. 4 is obtained. Normally, when vibration energy is applied from the outside, the weight body 30 vibrates in the apparatus housing, so that the reference numerals in the table shown in FIG. 4 are inverted and the electric charges are synchronized with the vibration cycle. The amount of electricity generated will also increase or decrease periodically.

In reality, the vibration energy given from the outside has each coordinate axis direction component in the XYZ three-dimensional coordinate system, so that the displacement of the weight body 30 is Δx (±), Δy (±), Δz (±). ) Is synthesized, and it changes from moment to moment. Therefore, for example, when the displacements Δx (+) and Δz (+) occur at the same time, both positive charges and negative charges are generated in the upper layer electrodes E13 and E23 as shown in the table of FIG. Therefore, some of the charges generated in the upper layer electrodes E13 and E23 are canceled out and cannot be effectively taken out.

As described above, depending on the vibration form of the weight body 30, 100% efficient power generation is not always performed, but as a whole, the vibration energy in the X-axis direction and the vibration energy in the Z-axis direction of the weight body 30 are taken into consideration. It is possible to generate electricity by extracting both vibration energy. As described above, it is a feature of the power generation element according to the first embodiment of the present invention that power generation using the biaxial component of the vibration energy of the weight body 30 becomes possible, and such a feature. As a result, the purpose of converting vibrational energy containing various directional components into electrical energy with as little waste as possible and obtaining high power generation efficiency is achieved.

The power generation circuit 60 plays a role of rectifying the current generated based on the electric charges generated in the upper layer electrodes E11 to E23 and the lower layer electrodes E0 and extracting electric power. In the case of the embodiment shown here, since the lower layer electrode E0 functions as a common electrode to secure the reference potential, the current flowing from the upper layer electrodes E11 to E23 and the current flowing into the upper layer electrodes E11 to E23 are actually used. It may be collected separately and stored.

FIG. 5 is a circuit diagram showing a specific configuration of the power generation circuit 60 used in the power generation element shown in FIG. Here, P11 to P23 show a part of the piezoelectric element 50, and correspond to the parts directly below the upper layer electrodes E11 to E23, respectively. Further, E0 indicated by a white circle on the circuit diagram corresponds to the lower layer electrode, and E11 to E23 correspond to the upper layer electrode. D11 (+) to D13 (-) are rectifying elements (diodes), and each rectifying element with a reference numeral (+) plays a role of extracting the positive charge generated in each upper layer electrode, and the reference numeral (−) Each rectifying element marked with is responsible for extracting the negative charge generated in each upper layer electrode. Similarly, D0 (+) and D0 (−) are also rectifying elements (diodes) and play a role of extracting positive and negative charges generated in the lower electrode E0.

On the other hand, Cf is a capacitance element (capacitor) for smoothing, and the positive charge taken out is supplied to the positive electrode terminal (upper terminal in the figure) and the negative charge taken out to the negative electrode terminal (lower terminal in the figure). Is supplied. As described above, since the amount of electric charge generated by the vibration of the weight body 30 increases or decreases in a cycle corresponding to the vibration, the current flowing through each rectifying element becomes a pulsating current. The capacitive element Cf plays a role of smoothing this pulsating flow. When the vibration of the weight body 30 is stable and steady, the impedance of the capacitive element Cf can be almost ignored.

The ZL connected in parallel to the capacitive element Cf indicates the load of the device that receives the power generated by the present power generation element. In order to improve the power generation efficiency, it is preferable to match the impedance of the load ZL with the internal impedance of the piezoelectric element 50. Therefore, when a device to be supplied with power is assumed in advance, it is preferable to design the power generation element by adopting a piezoelectric element having an internal impedance matched with the impedance of the load ZL of the device.

After all, the power generation circuit 60 is directed toward the positive electrode side of the capacitive element Cf from the capacitive elements Cf and the positive charges generated in the upper layer electrodes E11 to E23 from the upper layer electrodes E11 to E23 to the positive electrode side of the capacitive element Cf. From the negative electrode side of the capacitive element Cf in order to guide the negative charge generated in each of the upper layer electrodes E11 to E23 and the positive charge rectifying elements D11 (+) to D23 (+) in the forward direction to the negative electrode side of the capacitive element Cf. It has negative charge rectifying elements D11 (-) to D23 (-) whose forward direction is toward each upper layer electrode E11 to E23, and the electric energy converted from the vibration energy is smoothed by the capacitive element Cf. It will fulfill the function of supplying the load ZL.

As can be seen from the circuit diagram of FIG. 5, the load ZL includes the positive charge taken out by the positive charge rectifying elements D11 (+) to D13 (+) and the negative charge rectifying element D11 (−). The negative charge taken out by ~ D13 (−) will be supplied. Therefore, in principle, the most efficient power generation is possible if the total amount of positive charges and the total amount of negative charges generated in the upper layer electrodes E11 to E23 are equal to each other at each moment. In other words, when the total amount of positive charges and the total amount of negative charges generated at a certain moment are unbalanced, only the equal amount of both is used as electric power in the load ZL.

Of course, in reality, the electric charge generated by the piezoelectric element is temporarily accumulated in the smoothing capacitance element Cf, so that the behavior of the power generation operation actually performed is not an instantaneous phenomenon but a phenomenon obtained by taking a time average. It is something that should be captured, and complicated parameter settings are required for accurate analysis. However, as a general theory, it is preferable to make the total amount of positive charges and the total amount of negative charges generated in each upper layer electrode E11 to E23 equal at each moment in order to perform efficient power generation.

In the case of the embodiment shown here, in the upper layer electrode shown in FIG. 3, the right side electrode E11 and the left side electrode E13 are plane-symmetrical with respect to the YZ plane, and similarly, the right side electrode E21 and the left side electrode E23 are YZ. It is plane symmetric with respect to the plane. If such a symmetric structure is adopted, it means that when the weight body 30 vibrates in the X-axis direction, the total amount of positive charges and the total amount of negative charges generated are equal for these four upper-layer electrodes. do. The merit of arranging a pair of electrodes, the right side electrode and the left side electrode, on both sides of the center electrode is that the total amount of positive charges and the total amount of negative charges are equalized with respect to vibration in the X-axis direction. It is in the point to be obtained.

Finally, I would like to mention another condition for efficient power generation based on vibrations given from the outside. That is, the resonance frequency of the weight body 30 is matched with the vibration frequency given from the outside. Generally, the vibration system has a resonance frequency uniquely determined according to its unique structure, and when the frequency of vibration given from the outside matches the resonance frequency, the vibrator is vibrated most efficiently. It will be possible to make it, and its amplitude will also be maximized. Therefore, when the frequency of vibration given from the outside is assumed in advance (for example, when it is predetermined to be mounted on a specific vehicle and used, and the frequency applied from the vehicle is known), the power generation element At the structural design stage, it is preferable to design so that the resonance frequency matches the frequency.

<<< §2. Modification example of the first embodiment >>>
Here, some modifications of the two-axis power generation type power generation element according to the first embodiment described in §1 will be described.

<2-1 Deformation example of the number of upper layer electrodes>
FIG. 6 is a plan view showing a modified example of the power generation element shown in FIG. The only difference between the two is the number of upper electrodes and their length. That is, in the case of the power generation element shown in FIG. 3, a total of 6 sets of upper layer electrodes E11 to E23 were formed as described above, whereas in the case of the power generation element shown in FIG. 6, a total of 3 sets of upper layer electrodes E31 were formed. ~ Only E33 is formed. Since there is no difference in other structures, a detailed structural description of the modification of FIG. 6 is omitted (of course, the power generation circuit is rectified with respect to the three sets of upper layer electrodes E31 to E33 instead of those shown in FIG. The one that connects the elements and takes out the power will be used).

Here, in the case of the power generation element shown in FIG. 3, the upper layer electrode group includes the weight body side electrode groups E11 to E13 arranged in the vicinity of the connection portion of the plate-shaped bridge portion 20 with the weight body 30, and the plate-shaped bridge portion. It is composed of fixed portion side electrode groups E21 to E23 arranged in the vicinity of the connecting portion of 20 with the fixing portion 10, and the length in the longitudinal direction (Y-axis direction) thereof is arranged in the vicinity of the connecting portion. It is set to the required length. On the other hand, the three sets of upper layer electrodes E31 to E33 in the modified example shown in FIG. 6 have the weight body side electrode groups E11 to E13 and the fixed portion side electrode groups E21 to E23 on the opposite side, respectively. It corresponds to the one that is stretched in the direction, connected and fused. Therefore, the upper layer electrodes E31 to E33 have the same length as the plate-shaped bridge portion 20.

FIG. 7 is a table showing the polarities of charges generated in the upper layer electrodes E31 to E33 when the weight body 30 of the power generation element shown in FIG. 6 is displaced in each coordinate axis direction. Considering that the table of FIG. 4 can be obtained for the power generation element shown in FIG. 3, it can be easily understood that the table of FIG. 7 can be obtained for the power generation element shown in FIG. Therefore, for the power generation element shown in FIG. 6, if a power generation circuit similar to the circuit shown in FIG. 5 is prepared, the electric charge generated in each of the upper layer electrodes E31 to E33 can be taken out as electric power.

Actually, when the weight body 30 vibrates in the X-axis direction as shown in FIG. 2 (a) or in the Z-axis direction as shown in FIG. 2 (b), it occurs in the plate-shaped bridge portion 20. The stretching stress in the longitudinal direction (Y-axis direction) is the part where the circular symbol with "+" or "-" is described in FIG. 2, that is, the vicinity of the connection part with the weight body 30 and the fixing part 10. It will be concentrated in the vicinity of the connection part of. The embodiment shown in FIG. 3 is an example in which the upper layer electrodes E11 to E23 are arranged only in these stress concentration portions, and is an example in which the most efficient electrode arrangement is performed. On the other hand, the embodiment shown in FIG. 6 is an example in which the upper layer electrodes are arranged over the entire area including the portion where the stress is not concentrated, and the amount of power generation with respect to the unit electrode area is not always efficient. It becomes possible to reduce the number of electrodes.

In each embodiment, the upper layer electrode is composed of three types of electrodes, a center electrode, a right side electrode, and a left side electrode, and as described in §1, the vibration energy in the Z-axis direction of the weight body 30 and the vibration energy. It is possible to generate power based on the vibration energy in the X-axis direction, and with respect to the vibration in the X-axis direction, the effect of keeping the total amount of the generated positive charges and the total amount of the negative charges as balanced as possible can be obtained.

<2-2 Modification example in which the upper layer electrode is arranged on the side surface>
In both the embodiment shown in FIG. 3 and the embodiment shown in FIG. 6, the lower layer electrode E0 is formed on the upper surface of the plate-shaped bridge portion 20, the piezoelectric element 50 is formed on the upper surface of the lower layer electrode E0, and further, the central electrode is formed. , Right side electrode and left side electrode are formed on the upper surface of the plate-shaped bridge portion 20 via the lower layer electrode E0 and the piezoelectric element 50. Of the upper layer electrodes, the right side electrode and the left side electrode. The side electrodes may be formed in whole or in part on the side surface of the plate-shaped bridge portion 20 via the lower layer electrode E0 and the piezoelectric element 50.

FIG. 8 is a normal cross-sectional view showing variations in the arrangement mode of the upper layer electrodes in the power generation element according to the present invention. FIG. 8A is a normal cross-sectional view showing a cross section of the plate-shaped bridge portion 20 of the embodiment shown in FIG. 3 cut along the cutting line 8-8 in the figure. As shown in the figure, the lower layer electrode E0 and the piezoelectric element 50 are laminated on the upper surface of the plate-shaped bridge portion 20, and three types of upper layer electrodes E21, E22, and E23 are arranged on the upper surface thereof. Therefore, the polarization phenomenon of the piezoelectric element 50 occurs in the vertical direction in the figure. The arrangement of the upper layer electrodes of the embodiment shown in FIG. 6 is also the same.

On the other hand, in the embodiment shown in FIG. 8B, the right armpit electrode and the left armpit electrode are arranged on the side surface. That is, in this embodiment, the lower layer electrode E0B is formed on the side surface together with the upper surface of the plate-shaped bridge portion 20, and the piezoelectric element 50B is formed on the surface of the lower layer electrode E0B. That is, in the normal cross-sectional view, both the lower layer electrode E0B and the piezoelectric element 50B have a "U" shape, and are integrally formed from the upper surface of the plate-shaped bridge portion 20 to the left and right side surfaces. The arrangement of the three types of electrodes constituting the upper layer electrode group is the same as the point that the central electrode E22B is formed on the upper surface of the plate-shaped bridge portion 20 via the lower layer electrode E0B and the piezoelectric element 50B. The right side electrode E21B and the left side electrode E23B are formed on the side surface of the plate-shaped bridge portion 20 via the lower layer electrode E0B and the piezoelectric element 50B. Although only the fixed portion side electrode groups E21B to E23B are shown in FIG. 8B, the arrangement of the weight body side electrode groups E11B to E13B is also the same.

In this case, since each portion of the piezoelectric element 50B causes a polarization phenomenon in the thickness direction thereof, a polarization phenomenon occurs in the vertical direction of the figure for the portion formed on the upper surface of the plate-shaped bridge portion 20, and the plate shape is formed. A polarization phenomenon occurs in the left-right direction in the figure for the portion formed on the side surface of the bridge portion 20. Therefore, due to the stress generated in each portion of the plate-shaped bridge portion 20, a charge having a predetermined polarity is generated in any of the six upper layer electrodes E11B to E13B and E21B to E23B. Since the expansion / contraction state of each part of the plate-shaped bridge portion 20 shown in FIG. 2A does not change in its side surface, it eventually occurred if a circuit similar to the power generation circuit 60 shown in FIG. 5 was prepared. It is possible to extract electric power based on electric charge.

Compared with the embodiment shown in FIG. 8 (a), in the embodiment shown in FIG. 8 (b), the area of each upper layer electrode is larger, so that the amount of charge generated in the upper layer electrode group is also larger. Therefore, the power generation efficiency of the latter is higher than that of the former, but in the latter case, it is necessary to form the lower layer electrode, the piezoelectric element, and the upper layer electrode not only on the upper surface but also on the side surface of the plate-shaped bridge portion 20. Manufacturing costs will rise.

On the other hand, in the embodiment shown in FIG. 8 (c), the right armpit electrode and the left armpit electrode are arranged so as to be continuous from the upper surface to the side surface. In this embodiment as well, as in the embodiment shown in FIG. 8B, the lower layer electrode E0C is formed on the side surface together with the upper surface of the plate-shaped bridge portion 20, and the piezoelectric element 50C is formed on the surface of the lower layer electrode E0C. There is. Therefore, in the normal cross-sectional view, the lower layer electrode E0C and the piezoelectric element 50C have a "U" shape, and are integrally formed from the upper surface of the plate-shaped bridge portion 20 to the left and right side surfaces.

Here, the arrangement of the three types of electrodes constituting the upper layer electrode group is the same in that the central electrode E22C is formed on the upper surface of the plate-shaped bridge portion 20 via the lower layer electrode E0C and the piezoelectric element 50C. The right side electrode E21C and the left side electrode E23C are formed from the upper surface to the side surface of the plate-shaped bridge portion 20 via the lower layer electrode E0C and the piezoelectric element 50C. Although only the fixed portion side electrode groups E21C to E23C are shown in FIG. 8 (c), the arrangement of the weight body side electrode groups E11C to E13C is also the same.

As described above, each portion of the piezoelectric element 50B causes a polarization phenomenon in the thickness direction thereof. Therefore, also in the case of the embodiment shown in FIG. 8 (c), the stress generated in each portion of the plate-shaped bridge portion 20 causes the polarization phenomenon. , The electric charge of a predetermined polarity is generated in each of the six upper layer electrodes E11C to E13C and E21C to E23C. If a circuit similar to the power generation circuit 60 shown in FIG. 5 is prepared, the generated electric charge can be generated. Based on the power can be taken out.

Compared to the embodiment shown in FIG. 8 (b), in the embodiment shown in FIG. 8 (c), the area of the right armpit electrode and the left armpit electrode can be further secured, so that the electric charge generated in the upper electrode group can be secured. The amount of electricity can be increased accordingly, and the power generation efficiency can be further improved. However, since it is necessary to form the right armpit electrode and the left armpit electrode from the upper surface to the side surface, the manufacturing cost will further increase.

Of course, it is also possible to combine the arrangement forms of the upper layer electrodes in the examples shown in FIGS. 8 (a) to 8 (c) for each part. In FIG. 8 (d), the arrangement form shown in FIG. 8 (b) is adopted for the right half, and the arrangement form shown in FIG. 8 (c) is adopted for the left half. Further, in this embodiment, the piezoelectric element is not formed as an integral structure but is divided into two portions 51D and 52D.

Specifically, in the embodiment shown in FIG. 8 (d), the lower layer electrode E0D is formed on the side surface together with the upper surface of the plate-shaped bridge portion 20, and the piezoelectric elements 51D and 52D are formed on the surface thereof. The piezoelectric element 51D is formed at a position that covers the right side surface of the lower layer electrode E0D, and the piezoelectric element 52D is formed at a position that covers the upper surface and the left side surface of the lower layer electrode E0D. The arrangement of the three types of electrodes constituting the upper layer electrode group is such that the central electrode E22D is formed on the upper surface of the plate-shaped bridge portion 20 via the lower layer electrode E0D and the piezoelectric element 52D, and the right side electrode E21D is a plate. The lower layer electrode E0D and the piezoelectric element 51D are formed on the right side surface of the shaped bridge portion 20, and the left side electrode E23D is formed via the lower layer electrode E0D and the piezoelectric element 52D from the upper surface to the side surface of the plate-shaped bridge portion 20. Has been done.

In this way, the right side electrode and the left side electrode do not necessarily have to be symmetrical, but in order to keep the total amount of positive charges and the total amount of negative charges generated in relation to the vibration in the X-axis direction as balanced as possible. 8 (a) to 8 (c) are preferably shown in the example, and it is preferable to make them symmetrical.

Further, the piezoelectric element does not necessarily have to have an integral structure, and as shown in FIG. 8 (d), a separate and independent piezoelectric element may be arranged at a position corresponding to each upper layer electrode, but it is practical. Above, the manufacturing process is easier if the structure is integrated. Similarly, the lower layer electrodes may be arranged separately and independently at the positions corresponding to the upper layer electrodes, but in practice, the manufacturing process becomes easier if the integrated structure is used.

As a variation of the embodiment shown in FIG. 3 (the normal cross-sectional view corresponds to FIG. 8 (a)), the examples of FIGS. 8 (b) to 8 (d) have been described, but of course, the embodiment shown in FIG. Similar variations are possible for the example. Further, in the second embodiment described later, the same variation is possible with respect to the arrangement mode of the upper layer electrodes.

<<< §3. Second embodiment (3-axis power generation type) >>>
Subsequently, a second embodiment of the present invention will be described. The first embodiment described in §1 is a two-axis power generation type power generation in which power is generated by converting the vibration energy in the X-axis direction and the vibration energy in the Z-axis direction acting on the weight body 30 into electric energy. Although it is an element, the second embodiment described here is a three-axis power generation type power generation element having a function of converting vibration energy in the Y-axis direction into electric energy.

Of course, also in the case of the first embodiment, it is possible to convert the vibration energy in the Y-axis direction into electrical energy, but as described above, the conversion efficiency is very low, and the vibration in the X-axis or Z-axis direction. It is negligible compared to the energy conversion efficiency. In the second embodiment described here, basically, two sets of plate-shaped bridge portions in the first embodiment are prepared, and by combining these in the directions orthogonal to each other, the weight body has an X-axis and a Y-axis. , The vibration energy can be efficiently converted into electrical energy regardless of the direction of the Z-axis.

FIG. 9 is a plan view (upper view (a)) and a side sectional view (lower view (b)) of the basic structure 100 constituting the power generation element according to the second embodiment of the present invention. As shown in FIG. 9A, the basic structure 100 includes a plate-shaped member 110 for a fixing portion, a first plate-shaped bridge portion 120, an intermediate connecting portion 125, a second plate-shaped bridge portion 130, and a weight connection. It is a spiral structure having each part of a part 140 and a weight body 150.

Here, for convenience of explaining the vibration direction, the origin O is set at the position of the center of gravity of the weight body 150 in a state where the weight body 150 is stationary, and the XYZ three-dimensional coordinate system is defined as shown in the figure. That is, in the plan view of FIG. 9A, the X-axis is defined in the lower part of the figure, the Y-axis is defined in the right side of the figure, and the Z-axis is defined in the vertical upper part of the paper surface. In the side sectional view of FIG. 9B, the Z axis is defined in the upper part of the figure, the Y axis is defined in the right side of the figure, and the X axis is defined in the vertical upper part of the paper surface. The side sectional view of FIG. 9 (b) corresponds to a view obtained by cutting the basic structure 100 shown in the plan view of FIG. 9 (a) in the YZ plane. Although not shown in FIG. 9A, the basic structure 100 is actually housed in the apparatus housing. FIG. 9B shows a bottom plate 200 that forms a part of the apparatus housing, and shows a state in which the lower surface of the plate-shaped member 110 for a fixing portion is fixed to the upper surface of the bottom plate 200. ..

The plate-shaped member 110 for the fixing portion has the same function as the fixing portion 10 in the first embodiment, and the root end portion (left end in the figure) of the first plate-shaped bridge portion 120 is used as the bottom plate 200 of the apparatus housing. It is a component to be fixed. On the other hand, the root end portion of the second plate-shaped bridge portion 130 is connected to the tip end portion (right end in the figure) of the first plate-shaped bridge portion 120 via the intermediate connecting portion 125, and the second plate-shaped bridge portion 130 is connected. A weight body 150 is connected to the tip of the bridge portion 130 via a weight connecting portion 140. As shown in FIG. 9A, the weight body 150 is a rectangular structure having a sufficient mass that functions as an oscillator, and the components 110, 120, 125, 130, arranged in a spiral shape. It is in a state of being supported by 140.

Although the first plate-shaped bridge portion 120 and the intermediate connecting portion 125 do not appear in FIG. 9B, the first plate-shaped bridge portion 120, the intermediate connecting portion 125, and the second plate-shaped bridge portion 130, The weight connecting portion 140 and the weight body 150 both have the same thickness (dimensions in the Z-axis direction). On the other hand, the plate-shaped member 110 for the fixing portion has an extra thickness portion below. Therefore, as shown in FIG. 9B, in a state where the lower surface of the plate-shaped member 110 for the fixing portion is fixed to the upper surface of the bottom plate 200, the first plate-shaped bridge portion 120, the intermediate connecting portion 125, and the second The plate-shaped bridge portion 130, the weight connecting portion 140, and the weight body 150 are all in a state of being raised from the upper surface of the bottom plate 200, and the weight body 150 is held in a suspended state.

Here, since at least the first plate-shaped bridge portion 120 and the second plate-shaped bridge portion 130 have flexibility, bending occurs due to the action of an external force. Therefore, when vibration is applied to the device housing from the outside, a force is applied to the weight body 150 by the vibration energy, and the weight body 150 vibrates in the device housing. For example, if the device housing is attached to a vibration source such as a vehicle so that the XY plane is the horizontal plane and the Z axis is the vertical axis, the weight body is caused by the vertical and horizontal vibrations applied from the vibration source. Vibration energy in each coordinate axis direction of XYZ is applied to 150.

After all, in the basic structure 100 shown in FIG. 9, the first plate-shaped bridge portion 120 and the second plate-shaped bridge portion 130, respectively, which have flexibility, are arranged in an L shape. The tip of the plate-shaped bridge portion 120 and the root end portion of the second plate-shaped bridge portion 130 are connected via an intermediate connecting portion 125, and a weight body is further beside the second plate-shaped bridge portion 130. It has a structure in which the tip end portion of the second plate-shaped bridge portion 130 and the corner portion of the weight body 150 are connected via the weight connection portion 140 so that the 150 is arranged. Moreover, since the root end portion of the first plate-shaped bridge portion 120 is fixed to the upper surface of the bottom plate 200 of the apparatus housing by the plate-shaped member 110 for the fixing portion that functions as the fixing portion, the first plate-shaped bridge portion The portion 120, the second plate-shaped bridge portion 130, and the weight body 150 are suspended above the bottom plate 200 of the apparatus housing in a state where no external force acts.

In particular, in the basic structure 100 shown in FIG. 9, the fixing portion is composed of a plate-shaped member 110 for the fixing portion extending along the longitudinal axis L0 for the fixing portion parallel to the X axis, and the plate-shaped member for the fixing portion is formed. The root end portion of the first plate-shaped bridge portion 120 is fixed to one end of the 110. Moreover, the first plate-shaped bridge portion 120 is arranged so as to extend in the Y-axis direction about the first longitudinal axis Ly parallel to the Y-axis, and the second plate-shaped bridge portion 130 is arranged on the X-axis. It is arranged so as to extend in the X-axis direction about the parallel second longitudinal axis Lx. Therefore, the structure composed of the plate-shaped member 110 for the fixing portion, the first plate-shaped bridge portion 120, and the second plate-shaped bridge portion 130 has a “U” -shaped projection image on the XY plane. It has a U-shaped structure such that a plate-shaped weight body 150 is arranged in an internal region surrounded by the U-shaped structure.

Such a basic structure 100 has a structure suitable for mass production. That is, as can be seen from the plan view of FIG. 9A, in the plan view, the basic structure 100 is formed by etching or the like to form a “U” -shaped gap portion V on a rectangular plate-shaped member. It can be mass-produced by the process of creating a spiral structure as a whole.

For example, in the embodiment shown here, a silicon substrate having a side of 5 mm square is prepared, and a groove having a width of about 0.3 mm is formed by etching to form a “U” -shaped gap portion V. With a "U" -shaped structure having a width of about 0.5 mm, a plate-shaped member 110 for a fixing portion, a first plate-shaped bridge portion 120, an intermediate connecting portion 125, and a second plate-shaped bridge portion 130. , The weight connecting portion 140 is formed. Regarding the thickness of each part, the thickness of the first plate-shaped bridge portion 120, the intermediate connecting portion 125, the second plate-shaped bridge portion 130, the weight connecting portion 140, and the weight body 150 is set to 0.5 mm. The thickness of the plate-shaped member 110 for the fixing portion was set to 1 mm.

Of course, the dimensions of each part can be set arbitrarily. In short, if the first plate-shaped bridge portion 120 and the second plate-shaped bridge portion 130 are set to have flexible dimensions such that the weight body 150 can vibrate in each coordinate axis direction with a certain amplitude. Well, the weight body 150 may be set to a size having a sufficient mass to generate the vibration required for power generation by the vibration energy from the outside, and the plate-shaped member 110 for the fixing portion is the entire basic structure 100. May be set to a size that can be firmly fixed to the bottom plate 200 of the device housing.

As described above, the structure of the basic structure 100 which is a component of the power generation element according to the second embodiment has been described with reference to FIG. 9, but the power generation element may be further added to the basic structure 100. It is composed by adding an element.

FIG. 10 (a) is a plan view of the power generation element according to the second embodiment (not shown for the apparatus housing), and FIG. 10 (b) is a side sectional view of the power generation element cut along a YZ plane. There is (the device housing is also shown). As shown in FIG. 10B, a layered lower layer electrode E00 is formed on the entire upper surface of the basic structure 100, and a layered piezoelectric element 300 is formed on the entire upper surface thereof. An upper layer electrode group composed of a plurality of locally formed upper layer electrodes is formed on the upper surface of the piezoelectric element 300 (FIG. 10 (b) is a cross-sectional view taken along the YZ plane. Only the three upper layer electrodes Ex1, Ex2, and Ez1 arranged in the back of the cut surface appear in the figure).

The lower layer electrode and the upper layer electrode may be formed by using a general conductive material such as metal, as in the first embodiment. In the case of the example shown here, the lower layer electrode E00 and the upper layer electrode group are formed by a thin film-like metal layer having a thickness of about 300 nm (a metal layer composed of two layers of a titanium film and a platinum film). Further, as the piezoelectric element 300, a thin film having a thickness of about 2 μm such as PZT (lead zirconate titanate) or KNN (sodium niobate) is used.

As shown in FIG. 10B, in the case of this embodiment, the device housing is composed of the bottom plate 200 and the cover 400, and the basic structure 100 is housed in the device housing. As described above, the basic structure 100 is fixed to the upper surface of the bottom plate 200 by the plate-shaped member 110 for the fixing portion, and the weight body 150 is suspended in the device housing. The cover 400 is composed of a top plate 410 and a side plate 420, and the weight body 150 is displaced and vibrates in the internal space of the cover 400.

If the distance between the upper surface of the weight body 150 and the lower surface of the top plate 410 and the distance between the lower surface of the weight body 150 and the upper surface of the bottom plate 200 are set to appropriate dimensions, the top plate 410 and the bottom plate 200 can be set. Can function as a stopper member. That is, since the inner wall surface of the apparatus housing functions as a control member that limits the excessive displacement of the weight body 150, the weight body 150 is excessively accelerated (acceleration such that the plate-shaped bridge portions 120 and 130 are damaged). ) Can be added, the excessive displacement of the weight body 150 can be restricted, and the situation where the plate-shaped bridge portions 120 and 130 are damaged can be avoided. However, if the gap size between the top plate 410 and the weight body 150 or the gap size between the bottom plate 200 and the weight body 150 is too narrow, it will be affected by air damping and the power generation efficiency will decrease, so care must be taken.

In the case of the example shown here, as shown in FIG. 10 (a), the upper layer electrode group has 12 upper layer electrodes Ex1 to Ex4, Ey1 to Ey4, Ez1 to Ez4 (hatching in the figure clearly defines the electrode forming region. It is attached for the purpose of showing, and does not show the cross section). Since FIG. 10 (a) is a plan view of the power generation element viewed from above, the piezoelectric element 300 covering the entire surface of the basic structure can be seen. However, for convenience, FIG. 10 (a) is shown. The positions of the plate-shaped member 110 for the fixing portion, the first plate-shaped bridge portion 120, the second plate-shaped bridge portion 130, the weight connecting portion 140, and the weight body 150 are designated by a dashed line. It is shown by.

The role of the six upper layer electrodes arranged above the first plate-shaped bridge portion 120 is basically the role of the six upper layer electrodes arranged above the plate-shaped bridge portion 20 shown in FIG. It has the same role as. Similarly, the role of the six upper layer electrodes arranged above the second plate-shaped bridge portion 130 is basically the six elements arranged above the plate-shaped bridge portion 20 shown in FIG. It has the same role as the upper electrode.

Here, four upper layer electrodes Ex1 to Ex4 (left and right side electrodes arranged so as to extend along the second longitudinal axis Lx on the second plate-shaped bridge portion 130) including the reference numeral x, and The four upper layer electrodes Ey1 to Ey4 (left and right side electrodes arranged so as to extend along the first longitudinal axis Ly on the first plate-shaped bridge portion 120) containing the reference numeral y are mainly heavy. It is an electrode provided to play a role of extracting the charge generated based on the vibration energy in the horizontal direction (X-axis and Y-axis directions) of the weight body 150, and is four upper layer electrodes Ez1 to Ez4 including the symbol z. (The central electrodes arranged on the first longitudinal axis Ly of the first plate-shaped bridge portion 120 and on the second longitudinal axis Lx of the second plate-shaped bridge portion 130) are mainly weight bodies. It is an electrode provided to play a role of extracting a charge generated based on the vibration energy in the vertical direction (Z-axis direction) of 150.

Here, of the 12 upper layer electrodes shown in FIG. 10 (a), the three electrodes formed at the tip of the first plate-shaped bridge portion 120 are respectively on the right side of the first tip. The side electrodes Ey1, the first tip side center electrode Ez3, and the first tip side left side electrode Ey2 are called, and the three electrodes formed at the root end of the first plate-shaped bridge portion 120 are respectively. The first root end side right side electrode Ey3, the first root end side central electrode Ez4, and the first root end side left side electrode Ey4 are called and formed at the tip of the second plate-shaped bridge portion 130. The three electrodes are called the second tip side right side electrode Ex1, the second tip side center electrode Ez1, and the second tip side left side electrode Ex2, respectively, and the second plate-shaped bridge portion. The three electrodes formed at the root end of the 130 are the second root end side right side electrode Ex3, the second root end side central electrode Ez2, and the second root end side left side electrode Ex4, respectively. I will call it.

Here, too, the terms "right armpit" and "left armpit" mean the left and right sides of the upper surfaces of the plate-shaped bridge portions 120 and 130 when viewed from the root end portion side thereof. The central electrodes Ez3 and Ez4 are arranged on the first longitudinal axis Ly (central axis parallel to the Y axis) forming the center line of the first plate-shaped bridge portion 120, and the left and right side electrodes Ey1 to Ey4. Are arranged symmetrically with respect to the first longitudinal axis Ly on both the left and right sides thereof. Similarly, the central electrodes Ez1 and Ez2 are arranged on the second longitudinal axis Lx (central axis parallel to the X axis) forming the center line of the second plate-shaped bridge portion 130, and the left and right side electrodes. Ex1 to Ex4 are arranged on both the left and right sides thereof so as to be symmetrical with respect to the second longitudinal axis Lx.

As shown in FIG. 10B, this power generation element is further provided with a power generation circuit 500. In FIG. 10B, the power generation circuit 500 is shown as a simple block, but a specific circuit diagram will be described later. As shown in the figure, wiring is provided between the power generation circuit 500 and the lower layer electrode E00 and the 12 upper layer electrodes Ex1 to Ex4, Ey1 to Ey4, and Ez1 to Ez4, and the electric charge generated by each upper layer electrode is generated. , Taken out by the power generation circuit 500 via this wiring. In reality, each wiring can be formed by a conductive pattern formed on the upper surface of the piezoelectric element 300 together with each upper layer electrode. Further, when the basic structure is composed of a silicon substrate, the power generation circuit 500 can be formed on the silicon substrate (for example, a portion of the plate-shaped member 110 for a fixed portion).

After all, the power generation element according to the second embodiment is a power generation element that generates power by converting vibrational energy in each coordinate axis direction in the XYZ three-dimensional coordinate system into electrical energy, and is a first power generation element parallel to the Y axis. A first plate-shaped bridge 120 extending along the longitudinal axis Ly and having flexibility, connected to the first plate-shaped bridge 120 (via the intermediate connection 125) and parallel to the X-axis. A second plate-shaped bridge 130 extending along a second longitudinal axis Lx and having flexibility, and connected to the second plate-shaped bridge 130 (via a weight connecting portion 140). A device housing 400 for accommodating the weight body 150, the first plate-shaped bridge portion 120, the second plate-shaped bridge portion 130, and the weight body 150, and one end of the first plate-shaped bridge portion 120. A fixing portion (plate-shaped member 110 for fixing portion) fixed to the housing 400, a lower layer electrode E00 formed in layers on the surfaces of the first plate-shaped bridge portion 120 and the second plate-shaped bridge portion 130, and the lower layer electrode E00. Upper layer electrode group Ex1 to Ex4, Ey1 to Ey4, Ez1 to Ez4 consisting of a piezoelectric element 300 formed in a layer on the surface of the lower layer electrode E00 and a plurality of upper layer electrodes locally formed on the surface of the piezoelectric element 300. And a power generation circuit 500 that rectifies the current generated based on the charge generated in each upper layer electrode and the lower layer electrode to extract electric power.

As described above, in the power generation element having such a structure, when an external force that vibrates the device housing 400 acts, the weight body 150 vibrates in the device housing 400 due to the bending of the plate-shaped bridge portions 120 and 130. do. The bending of the plate-shaped bridge portions 120 and 130 is transmitted to the piezoelectric element 300, and the same bending occurs in the piezoelectric element 300. Since the piezoelectric element 300 has a property of generating polarization in the thickness direction by the action of stress that expands and contracts in the layer direction, electric charges are generated on the upper surface and the lower surface thereof, and the generated charges are the upper layer electrodes Ex1 to Ex4 and Ey1. It is taken out from ~ Ey4, Ez1 to Ez4 and the lower layer electrode E00.

In the case of the embodiment shown here, as in the embodiment described in §1, when the stress extending in the layer direction acts, a positive charge is generated on the upper surface side and a negative charge is generated on the lower surface side, and conversely, the stress contracting in the layer direction is generated. A piezoelectric element 300 is used in which a negative charge is generated on the upper surface side and a positive charge is generated on the lower surface side when the above action is performed. Of course, also in the case of this second embodiment, a piezoelectric element having any polarization characteristic may be used.

Next, let's look at the specific power generation operation of this power generation element. FIG. 11 is a plan view showing a stretched state of each upper layer electrode forming position when the weight body 150 of the basic structure 100 shown in FIG. 9 causes a displacement Δx (+) in the positive direction of the X axis. Similarly, FIG. 12 is a plan view showing a stretched state when a displacement Δy (+) in the positive direction of the Y axis is generated, and FIG. 13 is a stretched state when a displacement Δz (+) in the positive direction of the Z axis is generated. It is a plan view which shows. Such displacement occurs when the acceleration in the positive direction of each coordinate axis acts on the weight body 150, and the displacement causes the plate-shaped bridge portions 120 and 130 to bend, resulting in a basic structure. The body 100 is deformed. However, in FIGS. 11 to 13, for convenience of illustration, the depiction of the displacement state of the basic structure 100 is omitted, and the expansion / contraction state of each upper layer electrode formation position is indicated by an arrow (the arrow with arrows at both ends is an extension state). , A pair of arrows facing each other indicate a shrinking state).

When the weight body 150 causes a displacement Δx (+) in the positive direction of the X-axis, as shown in FIG. 11, the second tip-side right side electrode Ex1 arranged outside the spiral basic structure 100 A stress extending in the longitudinal direction acts on the second root end side right side electrode Ex3 and the first tip side right side electrode Ey1, but the first root end side right side electrode Ey3 is affected. , Stress that contracts in the longitudinal direction acts. On the other hand, the second tip side left armpit electrode Ex2, the second root end side left armpit electrode Ex4, and the first tip end side left armpit electrode Ey2 arranged inside the spiral basic structure 100 In each case, a stress that contracts in the longitudinal direction acts, but a stress that extends in the longitudinal direction acts on the first root end side left armpit electrode Ey4.

Although the first root end side right side electrode Ey3 is an electrode located on the outside of the spiral basic structure 100, it expands and contracts with the other right side electrodes Ex1, Ex3, and Ey1 located on the outside. The state is reversed, and although the first root end side right side electrode Ey4 is an electrode located inside the spiral basic structure 100, the left side electrodes Ex2 and Ex4 located inside the other. The expansion and contraction state is reversed from that of Ey2. In order to explain the reason why the expansion / contraction reversal occurs at the root end of the first plate-shaped bridge portion 120, a complicated theoretical development is required. Therefore, the description thereof is omitted here, but the inventor of the present application is a computer. By executing a structural mechanics simulation using the above, it has been confirmed that tensile stress as shown in the figure is generated (see FIG. 19 described later).

As for the four central electrodes Ez1 to Ez4 arranged on the center line, a slight opposite stress acts on the right half and the left half, so that the stress is balanced as a whole and expansion and contraction occurs. It can be considered that there is no such thing.

FIG. 11 shows a state when the displacement Δx (+) in the positive direction of the X axis occurs, but when the displacement Δx (−) in the negative direction of the X axis occurs, the weight body 150 is displaced in the opposite direction. The expansion and contraction state of each part is the reverse of the state shown in FIG. Therefore, when vibration energy having a vibration component in the X-axis direction is applied to the device housing 400, the expansion / contraction state shown in FIG. 11 and the inverted state thereof are alternately and repeatedly generated in each part of the basic structure 100. It will be.

On the other hand, when the weight body 150 causes a displacement Δy (+) in the positive direction of the Y-axis, as shown in FIG. 12, the right side of the second root end portion arranged outside the spiral basic structure 100. Electrodes Ex3, the first tip side right side electrode Ey1, and the first root end side right side electrode Ey3 are all subjected to stress that contracts in the longitudinal direction, but the second tip side right side electrode Ex1 A stress extending in the longitudinal direction acts on the electrodes. On the other hand, on the second root end side left armpit electrode Ex4 and the first tip end side left armpit electrode Ey2 and the first root end side left armpit electrode Ey4 arranged inside the spiral basic structure 100. In each case, a stress extending in the longitudinal direction acts on the second tip side left armpit electrode Ex2, but a stress contracting in the longitudinal direction acts on the second tip side left armpit electrode Ex2.

Although the second tip-side right armpit electrode Ex1 is an electrode located outside the spiral basic structure 100, it is in a stretched state with the other right armpit electrodes Ex3, Ey1, and Ey3 located outside. Is reversed, and the second tip-side left armpit electrode Ex2 is an electrode located inside the spiral basic structure 100, but is located inside the other left armpit electrodes Ex4, Ey2, Ey4. The expansion and contraction state is reversed. In order to explain the reason why the expansion / contraction reversal occurs at the tip of the second plate-shaped bridge portion 130, a complicated theoretical development is required. Therefore, the description thereof is omitted here, but the inventor of the present application uses a computer. By executing the structural mechanics simulation used, it has been confirmed that tensile stress as shown in the figure is generated (see FIG. 20 described later).

In this case as well, with respect to the four central electrodes Ez1 to Ez4 arranged on the center line, a slight opposite stress acts on the right half and the left half, so that the stress balances and expands and contracts as a whole. Can be considered not to occur.

FIG. 12 shows a state when a displacement Δy (+) in the positive direction of the Y axis occurs, but when a displacement Δy (−) in the negative direction of the Y axis occurs, the weight body 150 is displaced in the opposite direction. The expansion and contraction state of each part is the reverse of the state shown in FIG. Therefore, when vibration energy having a vibration component in the Y-axis direction is applied to the device housing 400, the expansion / contraction state shown in FIG. 12 and the inverted state thereof are alternately and repeatedly generated in each part of the basic structure 100. It will be.

Finally, when the weight body 150 causes a displacement Δz (+) in the positive direction of the Z axis, as shown in FIG. 13, three electrodes Ey1 and Ey2 on the tip end side of the first plate-shaped bridge portion 120 , Ez3 and the three electrodes Ex1, Ex2, and Ez1 on the tip side of the second plate-shaped bridge 130 are subjected to stress extending in the longitudinal direction, but the root end of the first plate-shaped bridge 120. Stress that contracts in the longitudinal direction acts on the three electrodes Ey3, Ey4, Ez4 on the side and the three electrodes Ex3, Ex4, Ez2 on the root end side of the second plate-shaped bridge portion 130. Although detailed explanation of the reason why such stress acts is omitted, the inventor of the present application has confirmed that elastic stress as shown in the figure is generated by performing a structural mechanics simulation using a computer. (See FIG. 21 described later).

FIG. 13 shows a state when a displacement Δz (+) in the positive direction of the Z axis occurs, but when a displacement Δz (−) in the negative direction of the Z axis occurs, the weight body 150 is displaced in the opposite direction. The expansion and contraction state of each part is the reverse of the state shown in FIG. Therefore, when vibration energy having a vibration component in the Z-axis direction is applied to the device housing 400, the expansion / contraction state shown in FIG. 13 and the inverted state thereof are alternately and repeatedly generated in each part of the basic structure 100. It will be.

In FIG. 14, in the power generation element shown in FIG. 10, when the lower layer electrode E00 is used as a reference potential and the weight body 150 is displaced in each coordinate axis direction, each upper layer electrode Ex1 to Ex4, Ey1 to Ey4, Ez1 to It is a table which shows the polarity of the charge generated in Ez4. In the table, the sign "+" indicates the generation of a positive charge, and the sign "-" indicates the generation of a negative charge. Further, the symbol "0" indicates a state in which no electric charge is generated at all, or a small amount of electric charge is generated as compared with the case indicated by the symbol "+" or the symbol "-". Practically, the generated charge in the column corresponding to the symbol "0" is not a significant amount, so it will be ignored in the following description.

As described above, when the weight body 150 is displaced in each coordinate axis direction, elastic stress as shown in FIGS. 11 to 13 is applied to each of the plate-shaped bridge portions 120 and 130. On the other hand, in the piezoelectric element 300, when a stress extending in the layer direction acts, a positive charge is generated on the upper surface side and a negative charge is generated on the lower surface side, and when a stress contracting in the layer direction acts, a negative charge is generated on the upper surface side and a positive charge is generated on the lower surface side. Has a polarization characteristic that causes. Based on these points, it can be easily understood that the table shown in FIG. 14 can be obtained.

For example, the result of each column of "displacement Δx (+)" in the first row of FIG. 14 is "+" in the upper electrode column of the extending portion and the upper electrode column of the contracting portion in the expansion / contraction distribution shown in FIG. "-", "0" is marked in the upper electrode column of the portion where expansion and contraction does not occur as a whole. Similarly, the results in each column of "displacement Δy (+)" in the second row correspond to the expansion / contraction distribution shown in FIG. 12, and the "displacement Δz (+)" in the third row. The results in each column correspond to the expansion and contraction distribution shown in FIG.

The table of FIG. 14 shows the electric charges generated by each upper layer electrode when the positive displacements Δx (+), Δy (+), and Δz (+) of each coordinate axis occur with respect to the weight body 150. However, when the displacements of each coordinate axis in the negative direction Δx (−), Δy (−), Δz (−) occur, the result of reversing the reference numerals in the table of FIG. 14 is obtained. Normally, when vibration energy is applied from the outside, the weight body 150 vibrates in the apparatus housing 400, so that the reference numerals in the table shown in FIG. 14 are inverted and the reference numerals are reversed in synchronization with the vibration cycle. , The amount of charge generated will also increase or decrease periodically.

In reality, the vibration energy given from the outside has each coordinate axis direction component in the XYZ three-dimensional coordinate system, so that the displacement of the weight body 150 is Δx (±), Δy (±), Δz (±). ) Is synthesized, and it changes from moment to moment. Therefore, for example, if the displacements Δx (+) and Δy (+) occur at the same time, or if the displacements Δx (+) and Δz (+) occur at the same time, as shown in the table of FIG. 14, the upper layer electrode Ex3 or Both positive and negative charges are generated in Ey2, and some of the charges are canceled out, so that they cannot be effectively taken out.

As described above, depending on the vibration form of the weight body 150, 100% efficient power generation is not always performed, but as a whole, the vibration energy in the X-axis direction and the vibration energy in the Y-axis direction of the weight body 150 are taken into consideration. It is possible to generate electricity by extracting energy in the three axes of vibration energy and vibration energy in the Z-axis direction. As described above, the point that power generation using the vibration energy of all three axes of the weight body 150 is possible is a feature of the power generation element according to the second embodiment of the present invention, and various features are provided depending on such features. The purpose of obtaining high power generation efficiency by converting vibration energy including various directional components into electric energy with as little waste as possible will be achieved.

The power generation circuit 500 plays a role of rectifying the current generated based on the electric charge generated in each of the upper layer electrodes Ex1 to Ez4 and the lower layer electrode E00 to extract electric power. In the case of the embodiment shown here, since the lower layer electrode E00 functions as a common electrode to secure the reference potential, the current flowing from the upper layer electrodes Ex1 to Ez4 and the current flowing into the upper layer electrodes Ex1 to Ez4 are actually used. And may be collected separately to store electricity.

FIG. 15 is a circuit diagram showing a specific configuration of the power generation circuit 500 used in the power generation element shown in FIG. The basic circuit configuration is the same as the power generation circuit 60 shown in FIG. That is, Px1 to Px4, Py1 to Py4, Pz1 to Pz4 represent a part of the piezoelectric element 300, and correspond to a part directly below the upper layer electrodes Ex1 to Ex4, Ey1 to Ey4, Ez1 to Ez4, respectively. Further, E00 indicated by a white circle on the circuit diagram corresponds to the lower layer electrode, and Ex1 to Ex4, Ey1 to Ey4, Ez1 to Ez4 correspond to the upper layer electrode.

Dx1 (+) to Dz24 (-) are rectifying elements (diodes), and each rectifying element with a reference numeral (+) plays a role of extracting the positive charge generated in each upper layer electrode, and the reference numeral (-) is used. Each rectifying element marked with is responsible for extracting the negative charge generated in each upper layer electrode.

A pair of independent positive and negative rectifying elements Dx1 (+), Dx1 (-) and the like are connected to the upper layer electrodes Ex1 to Ex4 and Ey1 to Ey4, whereas the upper layer electrodes Ez1 and Ez3 are connected to each other. A pair of positive and negative rectifying elements Dz13 (+) and Dz13 (-) common to both are connected, and a pair of positive and negative rectifying elements Dz24 (+) and Dz24 (-) common to both are connected to the upper layer electrodes Ez2 and Ez4. Has been done. As can be seen from the table of FIG. 14, this is because the upper layer electrodes Ez1 and Ez3 always generate only the charge of the same polarity, and the upper layer electrodes Ez2 and Ez4 always generate only the charge of the same polarity. Therefore, a common rectifying element can be used.

On the other hand, Cf is a capacitance element (capacitor) for smoothing, and the positive charge taken out is supplied to the positive electrode terminal (upper terminal in the figure) and the negative charge taken out to the negative electrode terminal (lower terminal in the figure). Is supplied. Similar to the power generation circuit 60 shown in FIG. 5, the capacitive element Cf plays a role of smoothing the pulsating current based on the generated charge, and the impedance of the capacitive element Cf is almost ignored when the vibration of the weight body 150 is stable and steady. Can be done. In the power generation circuit 60 shown in FIG. 5, the rectifying elements D0 (+) and D0 (−) are used to extract the electric charge generated in the lower layer electrode E0, but in the power generation circuit 500 shown in FIG. 15, the capacitance is A configuration is adopted in which both terminals of the element Cf are connected to the lower layer electrode E00 via the resistance elements Rd1 and Rd2. Even with such a configuration, it is possible to take out the electric charge generated in the upper and lower layer electrodes.

Here, too, the ZL connected in parallel to the capacitive element Cf indicates the load of the device that receives the power generated by the present power generation element. The resistance values of the resistance elements Rd1 and Rd2 are set so as to be sufficiently larger than the impedance of the load ZL. Similar to the power generation circuit 60 shown in FIG. 5, in order to improve the power generation efficiency, it is preferable to match the impedance of the load ZL with the internal impedance of the piezoelectric element 300. Therefore, when a device to be supplied with power is assumed in advance, it is preferable to design the power generation element by adopting a piezoelectric element having an internal impedance matched with the impedance of the load ZL of the device.

After all, in the power generation circuit 500, the direction from each upper layer electrode Ex1 to Ez4 toward the positive electrode side of the capacitive element Cf in order to guide the positive charge generated in the capacitive element Cf and each upper layer electrode Ex1 to Ez4 to the positive electrode side of the capacitive element Cf. From the negative electrode side of the capacitive element Cf in order to guide the negative charge generated in each of the upper layer electrodes Ex1 to Ez4 and the positive charge rectifying elements Dx1 (+) to Dz24 (+) in the forward direction to the negative electrode side of the capacitive element Cf. It has negative charge rectifying elements Dx1 (-) to Dz24 (+) whose forward direction is toward each upper layer electrode Ex1 to Ez4, and the electric energy converted from the vibration energy is smoothed by the capacitive element Cf. It will fulfill the function of supplying the load ZL.

Also in the circuit shown in FIG. 15, the load ZL includes the positive charge taken out by the positive charge rectifying elements Dx1 (+) to Dz24 (+) and the negative charge rectifying elements Dx1 (−) to Dz24 ( The negative charge taken out in-) will be supplied. Therefore, in principle, the most efficient power generation can be achieved by making the total amount of positive charges and the total amount of negative charges generated in each upper layer electrode Ex1 to Ez4 equal at each moment.

As described above, among the upper layer electrodes shown in FIG. 10, the left and right side electrodes are all arranged symmetrically with the longitudinal axis Lx or Ly as the central axis. If such a symmetrical structure is adopted, when the weight body 150 vibrates in the X-axis direction, as shown in FIG. 11, the total amount of positive charges generated in the pair of left and right side electrodes arranged at the same location is used. It is almost equal to the total amount of negative charge. Similarly, when the weight body 150 vibrates in the Y-axis direction, as shown in FIG. 12, the total amount of positive charges and the total amount of negative charges generated in the pair of left and right side electrodes arranged at the same location are approximately the same. Will be equal. In this way, the merit of arranging a pair of electrodes, the right side electrode and the left side electrode, on both sides of the center electrode is the total amount of positive charge and the total amount of negative charge for vibration in the X-axis direction and vibration in the Y-axis direction. The point is that the effect of equalizing with is obtained.

Of course, also in this second embodiment, the most efficient power generation is possible when the resonance frequency of the weight body 150 determined based on the unique structure of the basic structure 100 matches the vibration frequency given from the outside. become. Therefore, when the frequency of vibration given from the outside is assumed in advance, it is preferable to design the basic structure 100 so that the resonance frequency matches the frequency at the stage of structural design.

<<< §4. Power generation device using the second embodiment >>>
Here, an embodiment that enables more efficient power generation by preparing a plurality of sets of power generation elements (elements shown in FIG. 10) according to the second embodiment described in §3 will be described. In the present application, for convenience of distinguishing as terms, the set of devices shown in the first embodiment described in §1, the modified example described in §2, and the second embodiment described in §3 is referred to as "power generation." A device that uses a plurality of sets of these "power generation elements" and has a function of supplying electric power extracted by each power generation element to the outside is called a "power generation device".

FIG. 16 is a plan view showing the structure of the basic structure 1000 of the power generation device using four sets of power generation elements shown in FIG. 10 (in order to clearly show the plan shape, the inner portion of the structure is hatched. ). This basic structure 1000 is a fusion of four sets of basic structures 100A, 100B, 100C, and 100D. The individual basic structures 100A, 100B, 100C, and 100D all have the same structure as the basic structure 100 shown in FIG. 9, and the plate-shaped member 110 for the fixing portion, the first plate-shaped bridge portion 120, and the first, respectively. It has each part of the plate-shaped bridge part 130 and the weight body 150 of 2.

In FIG. 16, each part of the basic structures 100A, 100B, 100C, and 100D is also shown by adding A to D at the end of each reference numeral. For example, the basic structure 100A has each part of a plate-shaped member 110A for a fixing portion, a first plate-shaped bridge portion 120A, a second plate-shaped bridge portion 130A, and a weight body 150A. However, the basic structure adjacent to the top and bottom of the figure has a structure in which a pair of plate-shaped members 110 for fixing portions are fused. Therefore, the plate-shaped member 110A for the fixing portion of the basic structure 100A and the plate-shaped member 110B for the fixing portion of the basic structure 100B are actually fused to form one plate-shaped member 110AB for the fixing portion. Similarly, the plate-shaped member 110C for the fixing portion of the basic structure 100C and the plate-shaped member 110D for the fixing portion of the basic structure 100D are actually fused to form one plate-shaped member 110CD for the fixing portion. is doing.

Of course, the actual power generation device is realized by further adding a lower layer electrode, a piezoelectric element, an upper layer electrode, and a power generation circuit to the basic structure 1000 shown in FIG. Specifically, for example, a common lower layer electrode is formed on the entire upper surface of the basic structure 1000, a common piezoelectric element is formed on the entire upper surface thereof, and a plurality of individual electrodes are locally localized on the upper surface thereof. The upper layer electrode may be formed (of course, the lower layer electrode and the piezoelectric element may be configured independently for each part).

Here, the power generation circuit may be a circuit in which four sets of power generation elements are fused so that the generated charges taken out from the four sets of power generation elements can be collectively output. Specifically, in the power generation circuit 500 shown in FIG. 15, the rectifying element is connected to the upper electrode of each power generation element, but the capacitance element Cf is common to the four sets of power generation elements. It is provided so that the electric power energy obtained from all the power generation elements can be stored here. Further, the lower electrode E00 of the four sets of power generation elements are connected to each other so as to have the same potential. Of course, the resistance elements Rd1 and Rd2 may also be common to the four sets of power generation elements.

One set of power generation elements shown in FIG. 10 generates electric power based on the electric charge collected from the 12 upper layer electrodes, and the power generation device configured by using 4 sets of the electric charges has a total of 48 upper layer electrodes. It is possible to generate electricity based on the electric charge collected from.

When a power generation device is configured by combining a plurality of sets of power generation elements, the X-axis direction, the Y-axis direction, or both of some power generation elements are different from these directions in another part of the power generation elements. It is preferable that they are arranged in an orientation. If such an arrangement is adopted, the effect of making the total amount of positive charges and the total amount of negative charges generated in each upper layer electrode as equal as possible at each moment can be obtained, and more efficient power generation becomes possible.

For example, in the case of the basic structure 1000 shown in FIG. 16, the coordinate axes (X-axis and Y-axis defined as the basic structure 100 shown in FIG. 9) for each of the basic structures 100A to 100D are drawn in the figure. However, it can be seen that the combination of orientations is different for each.

That is, the basic structure 100A corresponds to the basic structure 100 shown in FIG. 9 rotated by 90 ° counterclockwise, and based on this basic structure 100A, the basic structure 100B is above and below the figure. It is a mirror image of the direction. Further, based on the basic structures 100A and B shown in the left half of the figure, the basic structures 100C and D shown in the right half of the figure are mirror images in the left-right direction of the figure. ..

After all, the power generation device configured by using the basic structure 1000 shown in FIG. 16 has four sets of power generation elements, and the first power generation element (element using the basic structure 100A) has the X-axis direction and Y. The second power generation element (element using the basic structure 100B) is arranged in a direction in which the Y-axis direction is reversed when the axial direction is used as a reference, and the third power generation element (element using the basic structure 100D) is arranged. ) Is arranged in a direction in which the X-axis direction is reversed, and the fourth power generation element (element using the basic structure 100C) is arranged in a direction in which both the X-axis direction and the Y-axis direction are reversed. .. As a result, the Z-axis direction of the first power generation element and the fourth power generation element is in the direction vertically upward on the paper surface, whereas the Z-axis direction of the second power generation element and the third power generation element is. , The direction is vertically downward on the paper.

In this way, if the power generation device is configured by adopting a complementary arrangement for the four sets of power generation elements, acceleration acts in a specific direction and the weight of each power generation element is displaced in the specific direction. Even in this case, since the orientations of the coordinate systems defined for each power generation element are different, the displacement directions for each coordinate system are complementary. Therefore, when a positive charge is generated in a specific upper layer electrode of one power generation element, a negative charge is generated in the corresponding upper layer electrode of another power generation element. Therefore, when viewed as a whole of the four sets of power generation elements, the effect of equalizing the total amount of generated positive charges and the total amount of negative charges can be obtained.

By the way, as already described, in order to efficiently generate power based on the vibration given from the outside, it is preferable to match the resonance frequency of the weight body 150 with the vibration frequency given from the outside. Therefore, when it is predetermined that the power generation element according to the present invention is mounted on a specific vehicle and used, for example, and the frequency f applied from the vehicle is known, the structural design of the basic structure 100 is performed. At this stage, it is preferable to design so that the resonance frequency of the weight body 150 matches the frequency f applied from the vehicle.

However, when the power generation element according to the present invention is provided as a general-purpose product, it cannot be designed as such a dedicated product. Therefore, the vibration frequency f considered to be the most common is determined, and the resonance frequency is determined. Must be designed to match the frequency f. In an actual usage environment, efficient power generation is possible if vibration with a frequency close to this resonance frequency f is applied, but the farther the external vibration frequency is from the resonance frequency f, the lower the power generation efficiency. It is undeniable to do.

Therefore, in order to enable power generation corresponding to a wide range of vibration frequencies, as described above, a plurality of sets of power generation elements are combined to form a power generation device, and a weight body of the plurality of power generation elements is used. It is possible to adopt an approach in which each has a different resonance frequency.

One of the concrete methods of changing the resonance frequency for each power generation element is to change the mass of each weight body. FIG. 17 is a plan view showing the structure of the basic structure of the power generation device according to the modified example of the power generation device shown in FIG. 16 (in order to clearly show the plan shape, the inner portion of the structure is hatched). .. In this modification, the mass of each weight of the four sets of power generation elements is varied by changing the planar area thereof.

The basic structure 2000 shown in FIG. 17 is a fusion of four sets of basic structures 100E, 100F, 100G, and 100H. Since each of the basic structures 100E, 100F, 100G, and 100H basically has the same structure as the basic structure 100 shown in FIG. 9, here, each part thereof also has reference numerals 110, 120, and 130, respectively. , 150 are indicated by adding E to H at the end (similar to the example shown in FIG. 16, the plate-shaped members 110EF and 110GH for the fixing portion are shared).

In the case of the basic structure 1000 shown in FIG. 16, the sizes (mass) of the weight bodies 150A, 150B, 150C, and 150D of the four sets of basic structures are the same, but the basic structure 2000 shown in FIG. 17 has the same size (mass). In this case, the sizes (mass) of the weight bodies 150E, 150F, 150G, 150H of the four sets of basic structures decrease in the order of 150E> 150F> 150G> 150H. Specifically, the weight bodies 150E, 150F, 150G, and 150H are all plate-shaped members having the same thickness, but as shown in FIG. 17, the areas of the projected images on the XY plane are different from each other. It is set to, and each mass is different.

Of course, the mass of each weight may be changed by changing the thickness (dimension in the Z-axis direction) of each weight. In short, a plurality of weight bodies are set so that the areas of the projected images on the XY plane are different from each other, the thicknesses in the Z-axis direction are set to be different from each other, or both are set. The masses of the weights of the power generation elements may be different.

The resonance frequency of the weight depends on its mass. Therefore, if the masses of the weight bodies 150E, 150F, 150G, and 150H are mE, mF, mG, and mH, respectively (mE> mF> mG> mH in the case of the example of FIG. 17, their resonance frequencies fE, fF). , FG, fH will be different from each other.

Another method of changing the resonance frequency of the weight for each power generation element is to change the structure of each plate-shaped bridge portion. Specifically, the areas of the projected images on the XY plane are set so as to be different from each other for the first plate-shaped bridge portion, the second plate-shaped bridge portion, or both of the plurality of power generation elements, or in the Z-axis direction. The thicknesses may be set so as to be different from each other, or both may be set. Even with such a setting, the resonance frequencies fE, fF, fG, and fH of the weight bodies 150E, 150F, 150G, and 150H can be made different from each other.

In this way, if the resonance frequencies of the weights of the four sets of power generation elements are different from each other, it is possible to generate power corresponding to a wide range of vibration frequencies. For example, in the case of the above example, four resonance frequencies fE, fF, fG, and fH are set, so if the frequency of vibration given from the outside is close to any of these, the proximity frequency is set. Efficient power generation can be expected for the power generation element that uses the resonance frequency.

Of course, if it is predetermined to be mounted on a specific vehicle and used, and the frequency f applied from the vehicle is known, the resonance frequency of each weight of each of the four sets of power generation elements is set to f. It is most preferable to set it. However, in the case of a power generation device provided as a general-purpose product, it is not possible to specify what kind of vibration environment it will be used in. In that case, set the predicted range of the vibration frequency that is considered to be the most common, and set the basic structure of each power generation element so that the four resonance frequencies fE, fF, fG, and fH are distributed within the predicted range. You can design it.

<<< §5. Modification example of the second embodiment >>>
Here, some modifications of the 3-axis power generation type power generation element according to the second embodiment described in §3 will be described.

<5-1 Deformation example of the number of upper layer electrodes>
§2-1 shows a modified example in which three upper layer electrodes E31 to E33 as shown in FIG. 6 are used instead of the six upper layer electrodes E11 to E23 in the two-axis power generation type power generation element shown in FIG. rice field. As described above, a modification for changing the number of upper layer electrodes is also possible for the 3-axis power generation type power generation element shown in FIG.

Specifically, in FIG. 10A, a pair of central electrodes arranged on the first longitudinal axis Ly among the six upper layer electrodes formed on the first plate-shaped bridge portion 120. Ez3 and Ez4 are fused to one elongated center electrode, and a pair of right side electrodes Ey1 and Ey3 arranged on the right side thereof are fused to one elongated right side electrode, and a pair arranged on the left side. The left side electrodes Ey2 and Ey4 may be fused with one elongated left side electrode. Then, in the first plate-shaped bridge portion 120, three elongated electrodes extending in a direction parallel to the Y-axis, similar to the upper layer electrodes formed on the plate-shaped bridge portion 20 of the modified example shown in FIG. The upper electrode will be arranged. Similarly, in FIG. 10A, the six upper layer electrodes formed on the second plate-shaped bridge portion 130 can be replaced with three elongated upper layer electrodes extending in the direction parallel to the X axis. can.

After all, in such a modification, the number of upper layer electrodes is reduced to six, but the configuration of the basic structure 100 remains unchanged. That is, also in the basic structure 100 in this modification, the root end portion of the first plate-shaped bridge portion 120 is fixed to the bottom plate 200 of the apparatus housing by the plate-shaped member 110 for the fixing portion that functions as the fixing portion. The tip of the first plate-shaped bridge 120 is connected to the root end of the second plate-shaped bridge 130, and the weight body 150 is connected to the tip of the second plate-shaped bridge 130. When an external force that vibrates the device housing is applied, the weight body 150 vibrates in each coordinate axis direction in the device housing due to the bending of the first plate-shaped bridge portion 120 and the second plate-shaped bridge portion 130. The points to be performed are exactly the same as those of the power generation element shown in FIG.

Moreover, the piezoelectric element 300 has a property of causing polarization in the thickness direction by the action of stress that expands and contracts in the layer direction, and the composition of the upper layer electrode group is such that the lower layer electrode is formed on the surface of the first plate-shaped bridge portion 120. A first upper layer electrode group formed via the E00 and the piezoelectric element 300, and a second upper layer electrode group formed on the surface of the second plate-shaped bridge portion 130 via the lower layer electrode E00 and the piezoelectric element 300. , Is also exactly the same as the power generation element shown in FIG.

Here, the first upper layer electrode group formed on the first plate-shaped bridge portion 120 is the first central electrode (a fusion of the electrodes Ez3 and Ez4 shown in FIG. 10A) and the first. Three types: the right side electrode (fused with the electrodes Ey1 and Ey3 shown in FIG. 10 (a)) and the first left side electrode (fused with the electrodes Ey2 and Ey4 shown in FIG. 10 (a)). It has an upper layer electrode, and each of these upper layer electrodes is arranged so as to extend along the first longitudinal axis Ly, faces a predetermined region of the lower layer electrode E00 with the piezoelectric element 300 interposed therebetween, and is the first. The center electrode of is arranged at the position of the center line along the first longitudinal axis Ly on the upper surface side of the first plate-shaped bridge portion 120, and the first right side electrode is the first center. It is arranged on one side of the electrode, and the first left side electrode is arranged on the other side of the first center electrode.

Further, the second upper layer electrode group formed on the second plate-shaped bridge portion 130 is a second central electrode (a fusion of electrodes Ez1 and Ez2 shown in FIG. 10A) and a second right. Three types of side electrodes (a fusion of electrodes Ex1 and Ex3 shown in FIG. 10A) and a second left side electrode (a fusion of electrodes Ex2 and Ex4 shown in FIG. 10A). It has an upper layer electrode, and each of these upper layer electrodes is arranged so as to extend along the second longitudinal axis Lx, faces a predetermined region of the lower layer electrode E00 with the piezoelectric element 300 interposed therebetween, and has a second layer electrode. The central electrode is arranged at the position of the center line along the second longitudinal axis Lx on the upper surface side of the second plate-shaped bridge portion 130, and the second right side electrode is the second central electrode. It is arranged on one side, and the second left side electrode is arranged on the other side of the second center electrode.

In this way, even in the modified example in which the 12 upper layer electrodes in the 3-axis power generation type power generation element shown in FIG. 10 are fused and replaced with the 6 upper layer electrodes, the upper layer electrodes are the center electrode, the right side electrode, and the right side electrode. Since it is composed of three types of electrodes, which are the left side electrodes, it is possible to obtain the effect of keeping the total amount of positive charges and the total amount of negative charges generated as balanced as possible with respect to vibrations in the X-axis direction or the Y-axis direction.

However, in practice, it is preferable to adopt an example using 12 upper layer electrodes as shown in FIG. 10 than to adopt a modification using the above-mentioned 6 upper layer electrodes. This is because the former can obtain higher power generation efficiency than the latter. The reason will be explained below.

In the embodiment using the twelve upper layer electrodes shown in FIG. 10, two sets of plate-shaped bridge portions 120 and 130 arranged in an L shape so as to be orthogonal to each other are used. Each of the plate-shaped bridge portions 120 and 130 has the same configuration as the plate-shaped bridge portion 20 shown in FIG. 3, and has six upper layer electrodes arranged on the upper surface side. However, the behavior of the elastic stress generated in each part when the weight body is displaced is slightly different.

That is, in the case of the plate-shaped bridge portion 20 shown in FIG. 3, when the weight body 30 is displaced in the positive direction of the X-axis, as shown in FIG. 2 (a), the left side of the plate-shaped bridge portion 20 (upper side in the figure). ) Is extended on both the fixed portion 10 side and the weight body 30 side, and the right side (lower side in the figure) of the plate-shaped bridge portion 20 is contracted on both the fixed portion 10 side and the weight body 30 side. As described above, since the expansion / contraction state of the same side surface of the plate-shaped bridge portion 20 is the same on the fixed portion 10 side and the weight body 30 side, the pair of right side electrodes E11 and E21 shown in FIG. 3A are used. Even if the fusion is performed and replaced with the right armpit electrode E31 shown in FIG. 6, and the pair of left armpit electrodes E13 and E23 shown in FIG. 3 (a) are fused and replaced with the left armpit electrode E33 shown in FIG. Since the polarities of the generated charges of the pair of electrodes are the same, the charges are canceled out and do not disappear.

However, in the case of the two sets of plate-shaped bridge portions 120 and 130 shown in FIG. 10, when the weight body 150 is displaced in the positive direction of the X-axis, as shown in FIG. 11, the right side of the first plate-shaped bridge portion 120. The first tip side right armpit electrode Ey1 and the first root end side right armpit electrode Ey3 arranged in the above are opposite to each other in the stretched state. For this reason, if the two are fused and replaced with a single elongated electrode, mutual cancellation will occur due to charges of different polarities. The same applies to the first tip end side left armpit electrode Ey2 and the first root end side left armpit electrode Ey4 arranged on the left side of the first plate-shaped bridge portion 120.

Further, in the case of the two sets of plate-shaped bridge portions 120 and 130 shown in FIG. 10, when the weight body 150 is displaced in the positive direction of the Y-axis, as shown in FIG. 12, the right side of the second plate-shaped bridge portion 130. The second tip side right armpit electrode Ex1 and the second root end side right armpit electrode Ex3 arranged in the above are opposite to each other in the stretched state. For this reason, if the two are fused and replaced with a single elongated electrode, mutual cancellation will occur due to charges of different polarities. The same applies to the second tip side left armpit electrode Ex2 and the second root end side left armpit electrode Ex4 arranged on the left side of the second plate-shaped bridge portion 130.

From such a point, practically, as shown in the embodiment shown in FIG. 10 (a), a total of 12 electrically independent upper layer electrodes are arranged, and the first upper layer electrode group is used as the first plate. The first root end side electrode group (Ey3, Ey4, Ez4) arranged near the root end portion of the shaped bridge portion 120 and the first arranged near the tip portion of the first plate-shaped bridge portion 120. The second upper layer electrode group is composed of the tip side electrode group (Ey1, Ey2, Ez3), and the second upper layer electrode group is arranged in the vicinity of the root end portion of the second plate-shaped bridge portion 130. It is composed of a group (Ex3, Ex4, Ez2) and a second tip side electrode group (Ex1, Ex2, Ez1) arranged near the tip of the second plate-shaped bridge 130, and is composed of a first root. Each of the end side electrode group, the first tip side electrode group, the second root end side electrode group, and the second tip side electrode group is a center electrode, a right side electrode, and a left side electrode. It is preferable to have an upper layer electrode.

As described above, the operating behavior of the 3-axis power generation type power generation element shown in FIG. 10 is slightly different from the operating behavior of the 2-axis power generation type power generation element shown in FIG. 3, and the plate-shaped bridge portion 20 shown in FIG. 3 It is not just a combination of two. That is, as shown in FIGS. 11 and 12, there is a portion where the expansion / contraction mode is reversed even though it is on the same side of the plate-shaped bridge portion with respect to the displacement of the weight body in the X-axis direction and the Y-axis direction. do.

Further, in the two-axis power generation type power generation element shown in FIG. 3, the power generation efficiency becomes extremely small when the vibration energy in the Y-axis direction is applied, as compared with the case where the vibration energy in the X-axis direction or the Z-axis direction is applied. (As described above, the vibration in the Y-axis direction is performed by the deformation operation of stretching or compressing the plate-shaped bridge portion 20 as a whole, which is considered to be due to the low mechanical deformation efficiency). In the 3-axis power generation type power generation element shown in FIG. 10, as shown in FIGS. 11 and 12, when vibration energy in the X-axis direction or the Y-axis direction is applied, eight upper layer electrodes Ex1 to Ex4 are used in both cases. , Ey1 to Ey4 can be charged with sufficient efficiency.

From this point of view, the 3-axis power generation type power generation element using the 12 upper layer electrodes shown in FIG. 10 can be said to be a power generation element having extremely high power generation efficiency.

<5-2 Deformation example in which the upper layer electrode is arranged on the side surface>
In §2-2, variations in the arrangement mode of the upper layer electrodes in the power generation element according to the first embodiment shown in FIG. 3 have been described with reference to FIG. These variations can be similarly applied to the power generation element according to the second embodiment shown in FIG.

In the side sectional view of FIG. 10B, the lower layer electrode E00 is arranged on the upper surface of the second plate-shaped bridge portion 130, the piezoelectric element 300 is arranged on the upper surface thereof, and the right armpit electrode Ex1 and the center electrode are arranged on the upper surface thereof. An embodiment in which Ez1 and the left armpit electrode Ex2 are arranged is shown. In this embodiment, the variation shown in FIG. 8 (a) is adopted.

That is, in this embodiment, the lower layer electrode E00 is formed on the upper surface of the first plate-shaped bridge portion 120 and the second plate-shaped bridge portion 130 (actually, the lower layer electrode E00 is the entire upper surface of the basic structure 100). The piezoelectric element 300 is formed on the upper surface of the lower layer electrode E00. Further, the first central electrodes Ez3 and Ez4, the first right side electrodes Ey1 and Ey3, and the first left side electrodes Ey2 and Ey4 are further formed on the upper surface of the first plate-shaped bridge portion 120 with the lower layer electrodes E00 and piezoelectric. The second central electrodes Ez1 and Ez2, the second right side electrodes Ex1 and Ex3, and the second left side electrodes Ex2 and Ex4 are formed via the element 300, and the upper surface of the second plate-shaped bridge portion 130 is formed. It is formed via the lower layer electrode E00 and the piezoelectric element 300.

On the other hand, when the variation shown in FIG. 8B is adopted, the lower layer electrode E00 is formed on the side surface together with the upper surface of the first plate-shaped bridge portion 120 and the second plate-shaped bridge portion 130. , The piezoelectric element 300 is formed on the surface of the lower layer electrode E00. Then, the first central electrodes Ez3 and Ez4 are formed on the upper surface of the first plate-shaped bridge portion 120 via the lower layer electrode E00 and the piezoelectric element 300, and the first right side electrodes Ey1, Ey3 and the first left are formed. The side electrodes Ey2 and Ey4 may be formed on the side surface of the first plate-shaped bridge portion 120 via the lower layer electrode E00 and the piezoelectric element 300. Similarly, the second central electrodes Ez1 and Ez2 are formed on the upper surface of the second plate-shaped bridge portion 130 via the lower layer electrode E00 and the piezoelectric element 300, and the second right side electrodes Ex1 and Ex3 and the second The left side electrodes Ex2 and Ex4 may be formed on the side surface of the second plate-shaped bridge portion 130 via the lower layer electrode E00 and the piezoelectric element 300.

On the other hand, when the variation shown in FIG. 8C is adopted, the lower layer electrode E00 is formed on the side surface together with the upper surface of the first plate-shaped bridge portion 120 and the second plate-shaped bridge portion 130, and the piezoelectric element is formed. 300 is formed on the surface of the lower layer electrode E00. Then, the first central electrodes Ez3 and Ez4 are formed on the upper surface of the first plate-shaped bridge portion 120 via the lower layer electrode E00 and the piezoelectric element 300, and the first right side electrodes Ey1, Ey3 and the first left are formed. The side electrodes Ey2 and Ey4 may be formed from the upper surface to the side surface of the first plate-shaped bridge portion 120 via the lower layer electrode E00 and the piezoelectric element 300. Similarly, the second central electrodes Ez1 and Ez2 are formed on the upper surface of the second plate-shaped bridge portion 130 via the lower layer electrode E00 and the piezoelectric element 300, and the second right side electrodes Ex1 and Ex3 and the second The left side electrodes Ex2 and Ex4 may be formed from the upper surface to the side surface of the second plate-shaped bridge portion 130 via the lower layer electrode E00 and the piezoelectric element 300.

Of course, with respect to the power generation element according to the second embodiment, it is also possible to combine the arrangement forms of the upper layer electrodes in the examples shown in FIGS. 8 (a) to 8 (c) for each part, for example, FIG. It is also possible to adopt the form illustrated in (d).

Further, the piezoelectric element 300 does not necessarily have to have an integral structure, and a separate and independent piezoelectric element 300 may be arranged at a position corresponding to each upper layer electrode. However, in practice, the manufacturing process is easier if the integrated structure is used. Similarly, the lower layer electrodes E00 may be arranged separately and independently at positions corresponding to the upper layer electrodes, but practically, the manufacturing process becomes easier if the integrated structure is used.

<Fixed portion consisting of 5-3 annular structure>
Here, as a modification shown in FIG. 10 described in §3, an example in which the fixed portion is configured by an annular structure will be described. FIG. 18 is a plan view (FIG. (A)) showing the structure of the basic structure 100I of the power generation device according to this modified example, and a side sectional view (FIG. (B)) obtained by cutting the basic structure 100I in the YZ plane. FIG. 18A is a plan view, but in order to clearly show the plan shape, the inner portion of the structure is hatched, and the positions of the 12 upper layer electrodes are shown in a rectangular shape.

In the embodiment shown in FIG. 10, as a fixing portion for fixing one end of the first plate-shaped bridge portion 120 to the bottom plate 200 of the apparatus housing, a plate-shaped fixing portion extending along the longitudinal axis L0 parallel to the X axis. The member 110 was used. On the other hand, in the modified example shown in FIG. 18, the annular structure 110I is used as the fixing portion. As shown in the figure, the annular structure 110I is a rectangular frame-shaped structure having four sides of 110I on the left side, 110I2 on the lower side, 110I3 on the right side, and 110I4 on the upper side, and as shown in FIG. 18B, the entire lower surface thereof. Is fixed to the upper surface of the bottom plate 200I of the device housing.

On the other hand, the root end portion of the first plate-shaped bridge portion 120I is connected to the vicinity of the lower end of the figure of the left side 110I1 of the annular structure 110I. The tip of the first plate-shaped bridge portion 120I is connected to the root end portion of the second plate-shaped bridge portion 130I via the intermediate connecting portion 125I, and the second plate-shaped bridge portion 130I Is connected to the weight body 150I via the weight connection portion 140I. After all, in the case of this modification, the fixing portion is composed of the annular structure 110I, and the first plate-shaped bridge portion 120I and the second plate-shaped bridge are formed in the internal region surrounded by the annular structure 110I. It has a structure in which a portion 130I and a weight body 150I are arranged.

As described above, when the annular structure 110I adopts a structure that surrounds the first plate-shaped bridge portion 120I, the second plate-shaped bridge portion 130I, and the weight body 150I while maintaining a predetermined distance, the annular structure is adopted. The 110I serves as a stopper member for controlling excessive displacement of the first plate-shaped bridge portion 120I, the second plate-shaped bridge portion 130I, and the weight body 150I. That is, even when an excessive acceleration (acceleration that damages each of the plate-shaped bridge portions 120I and 130I) is applied to the weight body 150I, the excessive displacement of each portion can be restricted, so that the plate-shaped bridge portion 120I , 130I can be avoided from being damaged.

<Addition of 5-4 eaves structure>
Another feature of the modified example shown in FIG. 18 is the eaves structure portion α1 and the second plate-shaped bridge portion in which the intermediate connecting portion 125I protrudes outward from the side surface of the tip portion of the first plate-shaped bridge portion 120I. The eaves structure portion α2 having an eaves structure portion α2 protruding outward from the side surface of the root end portion of the 130I, and the weight connecting portion 140I protruding outward from the side surface of the tip portion of the second plate-shaped bridge portion 130I. It is a point having a part α3. Since these eaves structure portions α1, α2, α3 are provided, recesses are formed in the inner portion of the annular structure 110I at positions corresponding to these eaves structure portions α1, α2, α3.

The inventor of the present application has discovered that the power generation efficiency of a power generation element can be further improved by adopting a structure provided with eaves structure portions α1, α2, and α3 as shown in the figure. This is because the stretching stress at the formation position of each upper layer electrode can be further increased by adopting the structure provided with the eaves structure portions α1, α2, α3. Let us show this based on the results of structural mechanics simulations using a computer.

FIG. 19A shows the stress generated in each of the plate-shaped bridge portions 120 and 130 when the weight body 150 causes a displacement Δx (+) in the positive direction of the X-axis with respect to the basic structure of the power generation element shown in FIG. It is a stress distribution map which shows the magnitude of. On the other hand, FIG. 19 (b) shows the displacement of the weight body 150 in the positive direction of the X-axis with respect to the basic structure of the power generation element (element adopting the structure provided with the eaves structure portions α1, α2, α3) shown in FIG. It is a stress distribution diagram which shows the magnitude of the stress generated in each plate-shaped bridge part when Δx (+) is generated. In each distribution map, when a predetermined displacement amount occurs, the regions where moderate tensile stress, strong tensile stress, moderate contraction stress, and strong contraction stress act are shown by applying unique hatching to each region. (See the legend at the top right of each figure).

Similarly, in FIG. 20, with respect to the basic structure of the power generation element shown in FIG. 10 (FIG. (a)) and the basic structure of the power generation element shown in FIG. 18 (FIG. (b)), the weight body 150 has a positive Y-axis. FIG. 21 is a stress distribution diagram showing the magnitude of stress generated in each plate-shaped bridge portion when a displacement Δy (+) in the direction is generated, and FIG. 21 is a basic structure of a power generation element shown in FIG. 10 (FIG. (a)). ) And the basic structure of the power generation element shown in FIG. 18 (FIG. (b)), the magnitude of the stress generated in each plate-shaped bridge portion when the weight body 150 causes a displacement Δz (+) in the positive direction of the Z axis. It is a stress distribution map which shows the above.

With reference to the stress distribution diagrams of FIGS. 19 (a) and 19 (b) and FIGS. 20 (a) and 20 (b), when the weight body 150 is displaced in the X-axis direction or the Y-axis direction, the left and right side electrodes Ex1 It can be seen that a relatively large tensile stress is generated at the formation positions of ~ Ex4, Ey1 to Ey4. On the other hand, referring to the stress distribution diagrams of FIGS. 21 (a) and 21 (b), when the weight body 150 is displaced in the Z-axis direction, the formation positions of all the upper layer electrodes Ex1 to Ex4, Ey1 to Ey4, Ez1 to Ez4 are formed. It can be seen that a relatively large tensile stress is generated in. Therefore, it can be understood that the arrangement of the 12 upper layer electrodes shown in FIG. 10 is an ideal arrangement.

Moreover, when comparing the upper figure (a) and the lower figure (b) in FIGS. 19 to 21, the stress distribution map shown in the lower figure (b) generally generates a relatively large stretching stress. You can see that it is doing. As shown in FIG. 18A, when the structure provided with the eaves structure portions α1, α2, α3 is adopted, the root end portion and the tip portion of the first plate-shaped bridge portion 120I and the second plate-shaped portion are adopted. This means that stress can be efficiently concentrated on the root end portion and the tip end portion of the bridge portion 130I, and the power generation efficiency of the power generation element can be further improved. Therefore, in practice, as shown in FIG. 18A, it is preferable to adopt a structure provided with eaves structure portions α1, α2, and α3.

<5-5 annular weight>
Next, a modified example in which a weight body is provided on the outside to form an annular structure will be described. In this modification, the roles of the fixed portion (annular structure 110I) and the weight body (150I) in the modification shown in FIG. 18 are reversed. That is, the annular structure 110I that was functioning as the fixing portion in the modified example shown in FIG. 18 was made to function as the weight body, and the plate-like body that was functioning as the weight body 150I was made to function as the fixing portion. It is a thing. For that purpose, the lower surface of the plate-like body functioning as the weight body 150I in FIG. 18 is fixed to the upper surface of the bottom plate of the apparatus housing, and the annular structure 110I functioning as the fixing portion in FIG. 18 is subjected to an external force. It suffices to be in a suspended state floating above the bottom plate of the device housing when the device housing does not act.

FIG. 22 shows a plan view (FIG. (A)) showing the structure of the basic structure 100J of the power generation element according to the modified example in which such a role is reversed, and a side sectional view (FIG. (b)) obtained by cutting the basic structure 100J in the YZ plane. )) Is shown. Comparing only the plan views shown in the upper part as FIG. (A), the basic structure 100I shown in FIG. 18 and the basic structure 100J shown in FIG. 22 seem to have exactly the same structure, but the lower part shows the figure (b). ), You can understand the difference between the two structures.

In the case of the basic structure 100J shown in FIG. 22, the plate-shaped member 150J arranged in the center serves as a plate-shaped fixing portion, which is thicker than the other portions. Then, the lower surface of the plate-shaped fixing portion 150J is fixed to the upper surface of the bottom plate 200J of the apparatus housing. On the other hand, as shown in FIG. 22 (a), at the upper right corner of the plate-shaped fixed portion 150J, the root end portion (upper end of the figure) of the first plate-shaped bridge portion 130J is interposed via the fixed end connecting portion 140J. ) Is connected. Further, the root end portion (right end in the figure) of the second plate-shaped bridge portion 120J is connected to the tip end portion (lower end in the figure) of the first plate-shaped bridge portion 130J via the intermediate connecting portion 125J. Further, an annular weight body 110J is connected to the tip end portion (left end in the figure) of the second plate-shaped bridge portion 120J.

As shown in FIG. 22A, the annular weight body 110J is a rectangular frame-shaped structure having four sides of 110J1 on the left side, 110J2 on the lower side, 110J3 on the right side, and 110J4 on the upper side, and is as shown in FIG. 22B. In addition, it is suspended in the air so as to float above the bottom plate 200J of the device housing.

In the embodiments described so far, the weight body is arranged at the inner position of the basic structure, but in the modified example shown in FIG. 22, the annular weight body 110J is arranged at the outer position of the basic structure 100J. Will be done. By adopting a structure in which the annular weight body is arranged on the outside in this way, it is generally easy to secure a large mass of the weight body, so that the mass of the weight body is increased to improve the power generation efficiency. It is advantageous on the above.

<5-6 spiral structure>
Here, a modified example in which the number of plate-shaped bridges is further increased to form a spiral structure will be described. FIG. 23 is a plan view showing the structure of the basic structure 100K of the power generation device according to this modification. Also in this figure, in order to clearly show the planar shape, the inner part of the structure is hatched, and the positions of the 24 upper layer electrodes are shown by rectangles. In this modified example, instead of the weight connecting portion 140I in the modified example shown in FIG. 18, a third plate-shaped bridge portion 140K, an intermediate connecting portion 145K, a fourth plate-shaped bridge portion 150K, and a weight connecting portion 160K are used. A structure that supports the weight body 170K via the structure is adopted.

Specifically, as shown in the figure, a rectangular frame-shaped annular structure 110K having four sides of 110K on the left side, 110K on the lower side, 110K on the right side, and 110K4 on the upper side is used as a fixing portion, and the entire lower surface thereof is a device housing. It is fixed to the upper surface of the bottom plate of. On the other hand, the root end portion of the first plate-shaped bridge portion 120K is connected to the vicinity of the lower end of the figure of the left side 110K1 of the annular structure 110K. The tip of the first plate-shaped bridge portion 120K is connected to the root end portion of the second plate-shaped bridge portion 130K via the intermediate connecting portion 125K, and the second plate-shaped bridge portion 130K is connected. The tip of the third plate-shaped bridge portion 140K is connected to the root end portion of the third plate-shaped bridge portion 140K via the intermediate connecting portion 135K, and the tip portion of the third plate-shaped bridge portion 140K is connected to the fourth plate-shaped bridge portion 140K via the intermediate connecting portion 145K. It is connected to the root end portion of the plate-shaped bridge portion 150K, and the tip portion of the fourth plate-shaped bridge portion 150K is connected to the weight body 170K via the weight connecting portion 160K.

After all, in the case of this modification, the fixed portion is composed of the annular structure 110K, and the first plate-shaped bridge portion 120K and the second plate-shaped bridge are in the internal region surrounded by the annular structure 110K. The structure is such that a portion 130K, a third plate-shaped bridge portion 140K, a fourth plate-shaped bridge portion 150K, and a weight body 170K are arranged. Here, the first plate-shaped bridge portion 120K and the third plate-shaped bridge portion 140K extend along the first and third longitudinal axes parallel to the Y axis, and the second plate-shaped bridge portion The 130K and the fourth plate-shaped bridge portion 150K extend along the second and fourth longitudinal axes parallel to the X axis. Thus, the weight body 170K is supported by a structure composed of four plate-shaped bridge portions 120K, 130K, 140K, and 150K connected in a spiral shape.

A point in which a lower layer electrode is formed on the upper surfaces of these four plate-shaped bridge portions 120K, 130K, 140K, and 150K, a piezoelectric element is arranged on the upper surface thereof, and an upper layer electrode group is locally provided at a predetermined position on the upper surface thereof. Is the same as in the previous examples. In the case of the illustrated example, three upper layer electrodes are arranged at the root end and the tip of each of the four plate-shaped bridge portions 120K, 130K, 140K, and 150K, and a total of 24 upper layer electrodes are formed. Has been done.

Although the structure is more complicated than that of the above-described embodiment, in this modification, the power generation circuit can extract power from the charges generated in the total of 24 upper-layer electrodes and the common lower-layer electrode, so that power can be generated. Efficiency can be improved.

FIG. 23 shows an example in which four plate-shaped bridge portions 120K, 130K, 140K, and 150K are provided, but of course, only three plate-shaped bridge portions 120K, 130K, and 140K are provided, and a third plate is provided. A weight body may be directly or indirectly connected to the tip of the bridge portion 140K. Further, the weight body may be connected to the end where five or more plate-shaped bridge portions are connected.

Generally speaking, in the structure having the first plate-shaped bridge portion and the second plate-shaped bridge portion described as the basic embodiment, between the second plate-shaped bridge portion and the weight body. Further, a third plate-shaped bridge portion to a K-th plate-shaped bridge portion may be provided, and a weight body may be connected to the end where a total of K plate-shaped bridge portions are connected (however, K). ≧ 3). At this time, the tip of the i-th plate-shaped bridge portion (however, 1 ≦ i ≦ K-1) is directly or indirectly connected to the root end portion of the (i + 1) plate-shaped bridge portion, and the K-th plate-shaped bridge portion is connected. The tip of the plate-shaped bridge is directly or indirectly connected to the weight body, and the j-th plate-shaped bridge (however, 1 ≦ j ≦ K) is parallel to the Y axis when j is an odd number. It extends along the longitudinal axis of the jth, and if j is an even number, it extends along the longitudinal axis of the jth parallel to the X axis.

Further, the structure from the root end of the first plate-shaped bridge to the tip of the K-th plate-shaped bridge forms a spiral path, and the weight body is surrounded by this spiral path. If they are arranged at the center position, K plate-shaped bridges and weights can be efficiently arranged in a limited space as shown in the example shown in FIG. 23. become. The example shown in FIG. 23 is an example in which K = 4 is set in the above general theory.

As shown in the example shown in FIG. 23, the fixed portion is configured by the annular structure 110K, and the first plate-shaped bridge portion to the K-th plate-shaped bridge portion and the weight are in the internal region surrounded by the annular structure 110K. If the structure in which the weight body is arranged is adopted, all the structures can be efficiently housed in the annular structure 110K.

If such a structure is used and a lower layer electrode, a piezoelectric element, and an upper layer electrode group are provided on the surface of the third plate-shaped bridge portion to the K-th plate-shaped bridge portion, the power generation circuit can be configured with these. Electricity can also be extracted from the charges generated in the upper and lower electrodes, and the power generation efficiency can be improved.

Also in the modified example shown in FIG. 23, the intermediate connection portions 125K, 135K, 145K and the weight connection portion 160K project outward from the side surfaces of the tip portions of the plate-shaped bridge portions 120K, 130K, 140K and 150K. Since the structure has an eaves structure, the effect of increasing the stretching stress at the formation position of each upper layer electrode can be obtained.

That is, in general terms, the tip of the i-th plate-shaped bridge (however, 1 ≦ i ≦ K-1) and the root end of the (i + 1) plate-shaped bridge are the intermediate connections of the i. When a structure is adopted in which the tip of the plate-shaped bridge portion of the Kth plate and the weight body are connected via the weight connection portion, the intermediate connection portion of the i-th is connected via the portion. It has an eaves structure that protrudes outward from the side surface of the tip of the plate-shaped bridge of the i-th, and the weight connection portion of the eaves that protrudes outward from the side of the tip of the plate-shaped bridge of K. If the structure is provided, the effect of increasing the stretching stress at the formation position of each upper layer electrode can be obtained, and more efficient power generation can be performed.

Of course, also in the modified example shown in FIG. 23, the annular structure 110K is used as the weight body and the weight body 170K is used as the fixing portion, and the roles are reversed, as in the modified example described in §5-5. It is also possible.

<Addition of 5-7 auxiliary weight>
Finally, a modified example of a device for adjusting the mass of the weight body will be described. As already described, in order to efficiently generate power based on the vibration given from the outside, it is preferable to match the resonance frequency of the weight body with the vibration frequency given from the outside. For example, in the case of a dedicated power generation element to be mounted on a specific vehicle and used, it is preferable to design so that the resonance frequency matches the frequency applied from the vehicle from the structural design stage. The easiest way to change the resonance frequency of the power generation element is to adjust the mass of the weight. Here, an embodiment in which an auxiliary weight body is added in order to adjust the mass of the weight body of each power generation element will be described.

FIG. 24 is a plan view (FIG. (A)) showing a modified example in which the mass of the entire weight body is adjusted by adding the auxiliary weight body 150L to the basic structure 100I of the power generation element shown in FIG. It is a side sectional view (FIG. (b)) cut in the YZ plane. As shown in the plan view of FIG. 24 (a), the structure of the basic structure 100L according to this modification when viewed from above is exactly the same as the structure of the basic structure 100I shown in FIG. 18 (a). Here, each part is shown with the same reference numerals as each part of the basic structure 100I shown in FIG. 18 (a).

On the other hand, as can be seen from the side sectional view of FIG. 24 (b), in the basic structure 100L according to this modification, the auxiliary weight body 150L is fixed to the lower surface of the weight body 150I, and the weight body 150I The aggregate of the auxiliary weight body 150L and the auxiliary weight body 150L functions as a weight body in the basic structure 100L. In other words, by adding the auxiliary weight body 150L, it is possible to increase the mass of the weight body in the basic structure 100L and lower the resonance frequency. Since the mass of the auxiliary weight body 150L can be adjusted by changing the material (specific gravity) and dimensions (thickness in the Z-axis direction and the area of the projected image on the XY plane), the auxiliary weight body 150L If the material and dimensions are appropriately determined, the resonance frequency of the basic structure 100L can be adjusted to an arbitrary value.

As described above, the method of adding the auxiliary weight body to adjust the resonance frequency is, of course, applicable to any of the embodiments described so far. 25 is a plan view (FIG. (A)) showing a modified example in which the mass of the entire weight body is adjusted by adding the auxiliary weight bodies 110M1 to 110M4 to the basic structure of the power generation element shown in FIG. 22. It is a side sectional view (FIG. (b)) cut from this in the YZ plane. As shown in the plan view of FIG. 25 (a), the structure of the basic structure 100M according to this modification when viewed from above is exactly the same as the structure of the basic structure 100J shown in FIG. 22 (a). Here, each part is shown with the same reference numerals as each part of the basic structure 100J shown in FIG. 22 (a).

In the case of the embodiment shown in FIG. 25, the central plate-shaped member 150J serves as a fixing portion fixed to the device housing, and the surrounding annular structure 110J (a rectangular frame composed of four sides 110J1 to 110J4) is a weight. Functions as a body. Here, the mass is increased by fixing the auxiliary weight body to the lower surface of the annular structure 110J. That is, as can be seen from the side sectional view of FIG. 25 (b), in the basic structure 100M according to this modification, the auxiliary weight bodies 110M1 to 110M4 are respectively on the lower surfaces of the respective sides 110J1 to 110J4 of the annular structure. It is fixed, and the aggregate of the annular weight body 110J and the auxiliary weight bodies 110M1 to 110M4 functions as the weight body in the basic structure 100M. Therefore, it is also possible to increase the mass of the weight body and lower the resonance frequency.

In the case of the illustrated example, the auxiliary weight bodies 110M1 to 110M4 are provided on all four sides 110J1 to 110J4 of the annular weight body 110J, but even if the auxiliary weight bodies are provided only on the lower surface of a specific side. It doesn't matter. However, in order to position the center of gravity of the entire weight body near the origin O and perform well-balanced and stable vibration, as shown in the illustrated example, the auxiliary weight body is evenly applied to all of the four sides 110J1 to 110J4. It is preferable to add it. The mass of the auxiliary weight body can be adjusted by changing the thickness in the Z-axis direction.

Since various materials can be used as the auxiliary weight, it is possible to select an appropriate material according to the need for mass adjustment. For example, if you need to make fine adjustments, use a material with a low specific density such as aluminum or glass, and if you need to increase the mass significantly, use a material with a high specific density such as tungsten. Just do it.

In practice, the basic structure 100I shown in FIG. 18 and the basic structure 100J shown in FIG. 22 are used to mass-produce general-purpose products having a standard resonance frequency suitable for the most general usage environment. Auxiliary weights having appropriate masses are added to general-purpose products to form the basic structure 100L shown in FIG. 24 and the basic structure 100M shown in FIG. 25, and the optimum resonance for each usage environment is formed. It suffices to provide a custom-made product with a frequency. By doing so, it is possible to provide custom-made products that are optimal for each usage environment while reducing costs by mass-producing general-purpose products.

In the examples shown in FIGS. 24 and 25, an example in which the auxiliary weight body is provided on the lower surface of the original weight body is shown, but the auxiliary weight body is provided on the upper surface or the side surface of the original weight body. It is also possible to provide it. However, if the auxiliary weight body is provided on the lower surface of the original weight body, it can be accommodated in the space formed between the auxiliary weight body and the bottom plate of the device housing, so that space can be saved. , It is preferable to provide it on the lower surface of the original weight body as shown in the illustrated example.

The method of improving the power generation efficiency by adding an auxiliary weight body to the weight body and adjusting the resonance frequency to the frequency of the usage environment has been shown above. Since the mass of the entire weight body is increased by adding the body, the effect of improving the power generation efficiency can also be obtained.

<<< §6. Other variants >>>
Finally, some further modifications relating to the various embodiments and modifications described so far will be described.

<6-1 Modification example regarding arrangement of upper layer electrodes>
In the embodiments described so far, three types of upper layer electrodes, a central electrode, a right armpit electrode, and a left armpit electrode, are arranged in the vicinity of the tip portion and the root end portion of each plate-shaped bridge portion. Each of the upper layer electrodes is arranged so as to extend along the longitudinal axis of the plate-shaped bridge portion, and faces a predetermined region of the lower layer electrode with the piezoelectric element interposed therebetween. Here, the central electrode is arranged at the position of the center line along the longitudinal axis of the plate-shaped bridge portion, the right armpit electrode is arranged on one side of the central electrode, and the left armpit electrode is It is located beside the other side of the central electrode.

If such three types of upper layer electrodes are arranged, charges having the polarities shown in the tables of FIGS. 4, 7, and 14 will be generated based on the displacement in each coordinate axis direction, and various types of charges will be generated. Vibration energy including directional components can be efficiently converted into electrical energy. However, in carrying out the present invention, it is not always necessary to arrange three types of upper layer electrodes, a central electrode, a right armpit electrode, and a left armpit electrode, and some of these may be omitted. An example of such a modification is described below.

FIG. 26 is a plan view showing a modified example in which the central electrodes E12 and E22 are omitted in the embodiment shown in FIG. It is exactly the same as the embodiment shown in FIG. 3, except that the central electrode is omitted. The central electrodes E12 and E22 shown in FIG. 3 are arranged at the position of the center line along the longitudinal axis (Y axis) of the plate-shaped bridge portion 20, and as shown in the table of FIG. 4, the weight body is exclusively used. 30 is an electrode used for power generation based on vibration in the Z-axis direction. However, as shown in this table, power generation based on the vibration of the weight body 30 in the Z-axis direction can also be performed using the left and right side electrodes E11, E13, E21, and E23 (FIG. 4). In the column of Δz (+) in the table, a “−” sign is written for each electrode, indicating that electric charge is generated for all electrodes).

Therefore, even when the central electrode is omitted and only the left and right side electrodes E11, E13, E21, and E23 are provided as in the modified example shown in FIG. 26, the vibration energy in the X-axis direction and the vibration energy in the Z-axis direction are provided. It is possible to convert both of them into electrical energy. As the power generation circuit used in this modification, if the partial piezoelectric elements P12, P22, the center electrodes E12, E22, and the rectifying elements D12 (+), D12 (-) are omitted from the power generation circuit 60 shown in FIG. good.

FIG. 27 is a plan view showing a modified example in which the central electrode is omitted in the embodiment shown in FIG. This modification is also exactly the same as the embodiment shown in FIG. 6, except that the central electrode is omitted. The central electrode E32 shown in FIG. 6 is arranged at the position of the center line along the longitudinal axis (Y axis) of the plate-shaped bridge portion 20, and as shown in the table of FIG. 7, exclusively the weight body 30. It is an electrode used for power generation based on vibration in the Z-axis direction. However, as shown in this table, power generation based on the vibration of the weight body 30 in the Z-axis direction can also be performed using the left and right side electrodes E31 and E33 (Δz in the table of FIG. 7). In the column of (+), a "-" sign is written for all electrodes, indicating that electric charges are generated for all electrodes).

Therefore, even when the central electrode is omitted and only the left and right side electrodes E31 and E33 are provided as in the modified example shown in FIG. 27, both the vibration energy in the X-axis direction and the vibration energy in the Z-axis direction are electrically operated. It can be converted into energy. As the power generation circuit used in this modification, a circuit that rectifies the current generated based on the electric charges generated in the left and right side electrodes E31 and E33 by a rectifying element may be used.

In short, the modification shown in FIGS. 26 and 27 is the two types of upper layers, the right side electrode and the left side electrode, as the upper layer electrode group in the two-axis power generation type power generation element described as the first embodiment in §1. This is an example in which only the electrodes are arranged and the central electrode is omitted. The right armpit electrode and the left armpit electrode are arranged so as to extend along the longitudinal axis of the plate-shaped bridge portion, and face a predetermined region of the lower layer electrode with the piezoelectric element interposed therebetween. Then, when the center line along the longitudinal axis is defined, the right armpit electrode is arranged on one side of the center line, and the left armpit electrode is arranged on the other side of the center line. It will be.

FIG. 28 is a plan view showing a modified example in which the central electrodes Ez1 to Ez4 are omitted in the embodiment shown in FIG. It is exactly the same as the embodiment shown in FIG. 10, except that the central electrode is omitted. The central electrodes Ez1 to Ez4 shown in FIG. 10 are arranged at positions of the center line (Ly or Lx) along the longitudinal axis of the first plate-shaped bridge portion 120 or the second plate-shaped bridge portion 130. As shown in the table of FIG. 14, the electrodes are exclusively used for power generation based on the vibration of the weight body 150 in the Z-axis direction. However, as shown in this table, power generation based on the vibration of the weight body 150 in the Z-axis direction can also be performed using the left and right side electrodes Ex1 to Ex4 and Ey1 to Ey4 (FIG. 14). In the column of Δz (+) in the table, a “+” or “−” sign is written for each electrode, indicating that electric charge is generated for all electrodes).

Therefore, as in the modified example shown in FIG. 28, even when the central electrode is omitted and only the left and right side electrodes Ex1 to Ex4 and Ey1 to Ey4 are provided, the X-axis, Y-axis, and Z-axis are in the three-axis directions. It is possible to convert vibration energy into electrical energy. The power generation circuit used in this modification includes the partial piezoelectric elements Pz1 to Pz4, the center electrodes Ez1 to Ez4, the rectifying elements Dz13 (+), Dz13 (-), Dz24 (+), and Dz24 from the power generation circuit 500 shown in FIG. The one omitting (-) may be used. In short, the modified example shown in FIG. 28 is an example in which the following changes are made to the three-axis power generation type power generation element described as the second embodiment in §3.

First, as the first upper layer electrode group, only two types of upper layer electrodes, the first right armpit electrode and the first left armpit electrode, are arranged, and the first center electrode is omitted. Here, the first right armpit electrode and the first left armpit electrode are arranged so as to extend along the first longitudinal axis Ly of the first plate-shaped bridge portion, and the lower layer electrodes sandwich the piezoelectric element. Facing a predetermined area. Then, when the first center line along the longitudinal axis Ly is defined, the first right armpit electrode is arranged on one side of the first center line, and the first left armpit electrode is arranged. Will be located on the other side of the first centerline.

On the other hand, as the second upper layer electrode group, only two types of upper layer electrodes, the second right armpit electrode and the second left armpit electrode, are arranged, and the second center electrode is omitted. Here, the second right armpit electrode and the second left armpit electrode are arranged so as to extend along the second longitudinal axis Lx of the second plate-shaped bridge portion, and the lower layer electrodes sandwich the piezoelectric element. Facing a predetermined area. Then, when the second center line along the longitudinal axis Lx is defined, the second right armpit electrode is arranged on one side of the second center line, and the second left armpit electrode is arranged. Will be located on the other side of the second centerline.

In FIG. 29, as a general theory, when the plate-shaped bridge portion 80 is connected to the fixed portion 70, there are three types of the right armpit electrode E1, the center electrode E2, and the left armpit electrode E3 in the vicinity of the root end portion thereof. It is a plan view which shows the example which formed the upper layer electrode (Fig. (A)), and the example which formed two kinds of upper layer electrodes, right armpit electrode E10 and left armpit electrode E20 (Fig. (B)). ..

The three sets of upper-layer electrodes shown in FIG. 29 (a) are all arranged so as to extend along the longitudinal axis L of the plate-shaped bridge portion 80, and the longitudinal axis L is the plate-shaped bridge portion 80. When the center line is in the longitudinal direction, the center electrode E2 is arranged on the center line L, the right side electrode E1 is arranged on one side of the center line (on the right side when viewed from the fixed portion 70 side), and the left side electrode E1 is arranged on the left side. The electrode E3 is arranged on the side of the other side (on the left side when viewed from the fixed portion 70 side). Moreover, in the case of the illustrated example, the arrangement patterns of the three types of upper layer electrodes are line-symmetrical with respect to the center line L.

When such an arrangement pattern is adopted, the central electrode E2 arranged on the center line L generates an electric charge when the weight body is displaced in the direction perpendicular to the paper surface, but in the direction parallel to the paper surface. No significant charge is generated when displaced. On the other hand, with respect to the right side electrode E1 and the left side electrode E3 arranged on both sides of the center line L (positions deviating from the center line L), even when the weight body is displaced in the direction perpendicular to the paper surface. Even when displaced in a direction parallel to the paper surface (specifically, a direction orthogonal to the central axis L), a significant charge is generated.

Therefore, even when three types of upper layer electrodes, the right side electrode E1, the center electrode E2, and the left side electrode E3, are formed, the center electrode E2 is omitted and the two types of upper layer electrodes, the right side electrode E1 and the left side electrode E3, are formed. Even when only the weight is used, both the vibration energy in the direction perpendicular to the paper surface and the vibration energy in the direction parallel to the paper surface can be converted into electrical energy.

The modified examples shown in FIGS. 26 to 28 can be said to be examples in which the central electrode is omitted based on such a viewpoint. Although FIGS. 26 to 28 show a modified example in which the central electrode is simply deleted, in practice, when implementing a modified example in which the central electrode is omitted, the areas of the right side electrode and the left side electrode are used. It is preferable to spread it and increase the amount of electric charge generated. In FIG. 29 (b), in the example shown in FIG. 29 (a), the central electrode E2 is deleted, the widths of the right armpit electrode E1 and the left armpit electrode E3 are widened, and the right armpit electrode E10 and the left armpit electrode E20 are shown. It was done.

The charge generation mode of the right side electrode E10 and the left side electrode E20 shown in FIG. 29 (b) is the same as the charge generation mode of the right side electrode E1 and the left side electrode E3 shown in FIG. 29 (a), respectively. , The amount of generated charge increases as the area increases. However, since the stress generated in each part when the weight body is displaced in the direction orthogonal to the central axis L becomes smaller as it gets closer to the central axis L, the amount of generated charge does not increase in proportion to the area. Of course, the right armpit electrode E10 and the left armpit electrode E20 may be provided on the side surface of the plate-shaped bridge portion as in the respective armpit electrodes E21B and E23B shown in FIG. 8 (b), or in FIG. 8 (c). Like the side electrodes E21C and E23C shown, they may be provided from the upper surface to the side surface of the plate-shaped bridge portion.

As mentioned above, with reference to FIGS. 26 to 29, an example in which the right armpit electrode and the left armpit electrode are arranged on both sides of the center line of the plate-shaped bridge portion has been described, but in addition to fulfilling the function as a power generation element. Then, it is not always necessary to arrange both the right armpit electrode and the left armpit electrode. For example, it is possible to generate electricity for biaxial vibration by using only one of the four upper layer electrodes shown in the modified example shown in FIG. 26, which is shown in the modified example shown in FIG. 28. Even if only one of the eight upper layer electrodes is used, it is possible to generate electricity for the vibration of the three axes. However, in practice, in order to improve the power generation efficiency as much as possible, two types of right armpit electrodes and left armpit electrodes are arranged near the root end and the tip of each plate-shaped bridge, or the center electrode is placed. , Right armpit electrode and left armpit electrode are preferably arranged.

<6-2 Modification example of providing a stopper structure>
As described above, the basic structure (fixed portion, plate-shaped bridge portion, weight body) of the power generation element according to the present invention can be configured by a silicon substrate. However, the plate-shaped bridge portion needs to be designed to have a thickness having flexibility, and cannot have sufficient rigidity. Therefore, if the weight body is excessively displaced due to the application of large vibrations, damage is likely to occur at both ends of the plate-shaped bridge portion. Therefore, in practice, it is preferable to provide a control structure for limiting the excessive displacement of the weight body.

FIG. 30 is a plan view showing a modified example in which a stopper structure is adopted for the basic structure shown in FIG. 18 (in order to clearly show the plan shape, a portion inside the structure is hatched). As shown in the figure, the basic structure 100N according to this modification uses the annular structure 110N as the fixing portion, as in the example shown in FIG. The annular structure 110N is a rectangular frame-shaped structure having four sides of 110N on the left side, 110N2 on the lower side, 110N3 on the right side, and 110N4 on the upper side, and the entire lower surface thereof is fixed to the upper surface of the bottom plate of the apparatus housing.

Further, the root end portion of the first plate-shaped bridge portion 120N is connected to the vicinity of the lower end portion of the figure of the left side 110N1 of the annular structure 110N. The tip of the first plate-shaped bridge portion 120N is connected to the root end portion of the second plate-shaped bridge portion 130N, and the tip portion of the second plate-shaped bridge portion 130N is connected to the weight connecting portion 140N. It is connected to the weight body 150N via.

The feature of the modification shown in FIG. 30 is that the fixing portion 110N is provided with stopper protrusions 110N5 and 110N6 protruding in the direction toward the weight body 150N, and the weight body 150N accommodates the tip portion of the stopper protrusion. It is at the point where the stopper groove 150NS is provided.

More specifically, in the case of the illustrated example, the stopper protrusion trunk portion 110N5 protrudes from the vicinity of the center of the left side 110N1 of the annular structure (fixed portion) 110N toward the weight body 150N. A stopper protrusion head 110N6 is attached to the tip of the stopper protrusion trunk 110N5. Here, the hammer-type structure including the stopper protrusion trunk portion 110N5 and the stopper protrusion head 110N6 is the stopper protrusion, and the weight body 150N side is capable of accommodating the tip portion of the stopper protrusion. , The stopper groove 150NS is formed. The tip of the stopper protrusion and the stopper groove 150NS are in a fitted state as shown in the figure, but they are not in close contact with each other, and no external force is applied to the weight body 150N. In, a predetermined gap is maintained between the outer surface of the tip of the stopper protrusion and the inner surface of the stopper groove 150NS.

While the stopper protrusion is fixed to the fixed portion 110N, the weight body 150N is displaced by the action of an external force. Therefore, when the weight body 150N is largely displaced, the tip portion of the stopper protrusion The outer surface comes into contact with the inner surface of the stopper groove 150NS, and further displacement is suppressed. In other words, the displacement of the weight body 150N is suppressed within the size range of the gap portion secured between the outer surface of the tip end portion of the stopper protrusion and the inner surface of the stopper groove 150NS. Therefore, even when an excessive acceleration (acceleration that damages each plate-shaped bridge portion 120N, 130N) is applied to the weight body 150N, the excessive displacement of each portion can be restricted, so that the plate-shaped bridge portion 120N can be restricted. , 130N can be avoided from being damaged.

In the example shown in FIG. 18, the positions of a total of 12 upper layer electrodes were shown, but in the example shown in FIG. 30, only the positions of a total of 8 upper layer electrodes are shown. This is because the modification regarding the arrangement of the upper layer electrodes described in §6-1 was adopted. Therefore, in the vicinity of the tip of the first plate-shaped bridge portion 120N, the first tip-side right armpit electrode Ey1 and the first tip-side left armpit electrode Ey2 are provided, and the first plate-shaped bridge portion 120N is provided. A first root end side right armpit electrode Ey3 and a first root end side left armpit electrode Ey4 are provided in the vicinity of the root end portion of the above. Similarly, in the vicinity of the tip of the second plate-shaped bridge portion 130N, a second tip-side right armpit electrode Ex1 and a second tip-side left armpit electrode Ex2 are provided, and the second plate-shaped bridge portion is provided. A second root end side right armpit electrode Ex3 and a second root end side left armpit electrode Ex4 are provided in the vicinity of the root end portion of 130N. Of course, a total of 12 upper layer electrodes may be arranged by adding a central electrode.

<6-3 Deformation example using both arms support type>
FIG. 31 is a plan view showing still another modification of the second embodiment shown in FIG. 18 (in order to clearly show the plan shape, a portion inside the structure is hatched). As shown in the figure, the basic structure 100P according to this modification uses the annular structure 110P as the fixing portion, as in the example shown in FIG. This annular structure 110P is a rectangular frame-shaped structure having four sides of 110P1 on the left side, 110P2 on the lower side, 110P3 on the right side, and 110P4 on the upper side. A portion 110P5 is provided, and a structure in which the weight body 150P is supported by two arms extending from the starting point portion 110P5 is adopted. Hereinafter, the structure in which the weight body is supported by the two arms in this way will be referred to as a double-arm support type.

As shown in the figure, this double-arm support type basic structure has a flexible first plate-shaped bridge portion 120P as a first arm and a flexible second arm. It has 2 plate-shaped bridge portions 130P. The weight body 150P is directly or indirectly connected to both the tip portion of the first plate-shaped bridge portion 120P and the tip portion of the second plate-shaped bridge portion 130P.

In the case of the illustrated example, both the tip portion of the first plate-shaped bridge portion 120P and the tip portion of the second plate-shaped bridge portion 130P are connected to the intermediate connecting portion 140P, and the weight body 150P is this. It is connected to the intermediate connection portion 140P. In other words, the weight body 150P is indirectly connected to both the tip portion of the first plate-shaped bridge portion 120P and the tip portion of the second plate-shaped bridge portion 130P via the intermediate connecting portion 140P. ing.

The annular structure 110P including the starting point portion 110P5 functions as a fixing portion, and the entire lower surface thereof is fixed to the upper surface of the bottom plate of the apparatus housing. On the other hand, the lower surface of the first plate-shaped bridge portion 120P, the second plate-shaped bridge portion 130P, the intermediate connection portion 140P, and the weight body 150P is located above the lower surface of the annular structure 110P, and an external force acts on them. In the non-existing state, it is in a state of floating above the bottom plate of the device housing. That is, the first plate-shaped bridge portion 120P, the second plate-shaped bridge portion 130P, the intermediate connecting portion 140P, and the weight body 150P are housed in the apparatus housing in a state of being suspended in the air at the starting point portion 110P5. .. The root end portion of the first plate-shaped bridge portion 120P and the root end portion of the second plate-shaped bridge portion 130P are fixed to the apparatus housing via a starting point portion 110P5 that functions as a fixing portion.

The configuration of the layered electrode and the piezoelectric element in the power generation element using the basic structure 100P is the same as that of the embodiment shown in FIG. That is, a layered lower layer electrode is formed on the surfaces of the first plate-shaped bridge portion 120P and the second plate-shaped bridge portion 130P, and a layered piezoelectric element is formed on the surface of the lower layer electrode. A plurality of upper layer electrodes are locally formed on the surface. The same applies to the point of using a power generation circuit that extracts electric power by rectifying the current generated based on the electric charge generated in the upper layer electrode and the lower layer electrode.

When an external force that vibrates the device housing acts on this power generation element, the weight body 150P is displaced in each coordinate axis direction in the device housing due to the bending of the first plate-shaped bridge portion 120P and the second plate-shaped bridge portion 130P. Vibrates to. Since the piezoelectric element has a property of causing polarization in the thickness direction by the action of stress that expands and contracts in the layer direction, electric power can be taken out by a power generation circuit as in the embodiment shown in FIG.

In this double-arm support type, the root end portion of the first plate-shaped bridge portion 120P and the root end portion of the second plate-shaped bridge portion 130P are at the same starting point portion 110P5 of the annular structure 110P (fixed portion). Since they are connected, the weight body 150P has a structure supported in the form of a cantilever with respect to the fixed portion, and the weight body 150P can be efficiently vibrated. Moreover, since the number of plate-shaped bridges is increased to two, there is an advantage that the electric charge generated by the piezoelectric element is increased.

In the example shown in FIG. 31, the shape of the basic structure is determined so that efficient power generation is possible based on the vibration component in the X-axis direction and the vibration component in the Y-axis direction. That is, in the case of this example, the portion near the tip portion 121P of the first plate-shaped bridge portion 120P extends in the direction parallel to the X axis, and the portion near the root end portion 123P of the first plate-shaped bridge portion 120P is Y. It extends in the direction parallel to the axis. The intermediate portion 122P between the tip portion vicinity portion 121P and the root end portion vicinity portion 123P is curved in a curved line. Similarly, the portion near the tip of the second plate-shaped bridge 130P extends in the direction parallel to the Y axis, and the portion near the root of the second plate-shaped bridge 130P 133P is parallel to the X axis. It extends in the direction. The intermediate portion 132P between the tip portion vicinity portion 131P and the root end portion vicinity portion 133P is curved in a curved line.

In the example shown in FIG. 31, a modified example relating to the arrangement of the upper layer electrodes described in §6-1 (an example in which the center electrode is omitted and the right armpit electrode and the left armpit electrode are arranged on both sides of the center line) is adopted. The positions of a total of eight upper-layer electrodes are shown.

That is, the upper layer electrodes are the first tip side upper electrode groups Ex11 and Ex12 formed on the surface of the tip vicinity portion 121P of the first plate-shaped bridge portion 120P via the lower layer electrode and the piezoelectric element. The first root end side upper layer electrode groups Ey11 and Ey12 formed on the surface of the root end portion vicinity portion 123P of the plate-shaped bridge portion 120P via the lower layer electrode and the piezoelectric element, and the second plate-shaped bridge portion. The second tip side upper layer electrodes groups Ey13 and Ey14 formed on the surface of the tip portion vicinity portion 131P of the 130P via the lower layer electrode and the piezoelectric element, and the root end portion vicinity portion 133P of the second plate-shaped bridge portion 130P. It is composed of a second root end side upper layer electrode group Ex13 and Ex14 formed on the surface of the surface via a lower layer electrode and a piezoelectric element.

Here, the first tip side upper layer electrode group has two types of upper layer electrodes, a first tip side right side electrode Ex11 and a first tip side left side electrode Ex12, and each of these upper layer electrodes. Is arranged so as to extend along the X-axis direction, faces a predetermined region of the lower layer electrode with the piezoelectric element interposed therebetween, and is parallel to the X-axis with the tip portion vicinity portion 121P of the first plate-shaped bridge portion 120P. When the first tip side center line L1 is defined, the first tip side right side electrode Ex11 is arranged on one side of the first tip side center line L1 and the first tip portion. The side left side electrode Ex12 is arranged on the other side of the first tip side center line L1.

Further, the first root end side upper layer electrode group has two types of upper layer electrodes, the first root end side right side electrode Ey11 and the first root end side left side electrode Ey12, and these upper layer electrodes. Each of the above is arranged so as to extend along the Y-axis direction, faces a predetermined region of the lower layer electrode with the piezoelectric element interposed therebetween, and is located on the Y-axis in the vicinity of the root end of the first plate-shaped bridge portion 120P. When the parallel first root end side center line L2 is defined, the first root end side right side electrode Ey11 is arranged on one side of the first root end side center line L2. The first root end side left side electrode Ey12 is arranged on the other side of the first root end side center line L2.

The second tip side upper layer electrode group has two types of upper layer electrodes, a second tip side right side electrode Ey13 and a second tip side left side electrode Ey14, and each of these upper layer electrodes has. , Arranged so as to extend along the Y-axis direction, facing a predetermined region of the lower layer electrode with the piezoelectric element interposed therebetween, and parallel to the Y-axis portion 131P near the tip of the second plate-shaped bridge portion 130P. When the tip side center line L3 of 2 is defined, the second tip side right side electrode Ey13 is arranged on one side of the second tip side center line L3, and is arranged on one side of the second tip side center line L3. The left side electrode Ey14 is arranged on the other side of the second tip side center line L3.

Finally, the second root end side upper layer electrode group has two types of upper layer electrodes, a second root end side right side electrode Ex13 and a second root end side left side electrode Ex14, and these upper layers. Each of the electrodes is arranged so as to extend along the X-axis direction, faces a predetermined region of the lower layer electrode with the piezoelectric element interposed therebetween, and X is formed in the portion near the root end of the second plate-shaped bridge portion 130P. When the second root end side center line L4 parallel to the axis is defined, the second root end side right side electrode Ex13 is arranged on one side of the second root end side center line L4. The second root end side left side electrode Ex14 is arranged on the other side of the second root end side center line L4.

Of course, it is also possible to form a total of 12 upper layer electrodes without omitting the central electrode. In that case, a first tip side center electrode is provided between the first tip side right side electrode Ex11 and the first tip side left side electrode Ex12, and the first root end side right side electrode Ey11 is provided. A first root end side central electrode is provided between the first root end side left side electrode Ey12, and between the second tip side right side electrode Ey13 and the second tip side left side electrode Ey14. Is provided with a second tip-side central electrode, and a second root-end-side central electrode is provided between the second root-end-side right side electrode Ex13 and the second root-end-side left-side electrode Ex14. Just do it.

Also in the embodiment shown in FIG. 31, an eaves structure portion is formed in the intermediate connecting portion 140P in order to concentrate stress on the tip portions and root ends of the plate-shaped bridge portions 120P and 130P. That is, in the intermediate connection portion 140P, the eaves structure portions α11 and α12 protruding from the side surfaces of the tip portion of the first plate-shaped bridge portion 120P to the left and right sides, and the side surfaces of the tip portion of the second plate-shaped bridge portion P130P. The eaves structure portions α13 and α14 protruding from the left and right sides are provided.

The eaves structure portion is also formed in the starting point portion 110P5 that functions as the fixing portion. That is, on the starting point portion 110P5, the side surfaces of the eaves structure portions α21, α22 and the root end portion of the second plate-shaped bridge portion 130P protruding from the side surfaces of the root end portion of the first plate-shaped bridge portion 120P to the left and right sides. The eaves structure portions α23 and α24 protruding from the left and right sides are provided.

As shown in the example shown in FIG. 31, the fixed portion is configured by the annular structure 110P, and the first plate-shaped bridge portion 120P and the second plate-shaped bridge portion 130P are formed in the internal region surrounded by the annular structure 110P. And the weight body 150P is arranged, and the first plate-shaped bridge portion 120P and the second plate-shaped bridge portion 130P have a curved structure, and the weight body 150P is arranged in the area surrounded by both of them. In this form, each member can be efficiently accommodated in a plane, and the annular structure 110P can be used as it is as a part of the apparatus housing.

The characteristics of the generated charges of the upper layer electrodes Ex11, Ex12, Ey11, and Ey12 on the first plate-shaped bridge portion 120P whose arrangement is shown in FIG. 31 are the characteristics of the generated charges of each upper layer electrode Ex1 in the embodiment shown in FIG. , Ex2, Ey3, and Ey4 are the same as the characteristics of the generated charges (see the table in FIG. 14). Further, since the planar shape of the embodiment shown in FIG. 31 is axisymmetric with respect to the axis of symmetry W (the axis in which the Y axis is tilted by 45 °) in the figure, it is formed on the second plate-shaped bridge portion 130P. The characteristics of the generated charge of each upper layer electrode are line-symmetrical with respect to the characteristic of the generated charge of each upper layer electrode formed on the first plate-shaped bridge portion 120P with respect to the axis of symmetry W.

Of course, also in the embodiment shown in FIG. 31, the roles of the fixed portion and the weight body are reversed, and the annular structure 110P that has functioned as the fixed portion functions as the weight body and functions as the weight body. In order to make the plate-shaped body 150P function as a fixing portion, the lower surface of the plate-shaped body 150P is fixed to the upper surface of the bottom plate of the device housing, and the annular structure 110P is in a state where no external force acts on the device housing. It is also possible to take a mode in which the body is suspended above the bottom plate.

Further, each right armpit electrode and each left armpit electrode may be provided on the side surface of the plate-shaped bridge portion as in the case of the armpit electrodes E21B and E23B shown in FIG. 8 (b), and in FIG. 8 (c). Like the side electrodes E21C and E23C shown, they may be provided from the upper surface to the side surface of the plate-shaped bridge portion.

FIG. 32 is a plan view showing a modified example in which the stopper structure described in §6-2 is adopted for the basic structure shown in FIG. 31. The basic structure of the basic structure 100Q according to this modification is the same as the basic structure 100P shown in FIG. 31. That is, the annular structure 110Q that functions as a fixing portion is a rectangular frame-shaped structure having four sides of 110Q1 on the left side, 110Q2 on the lower side, 110Q3 on the right side, and 110Q4 on the upper side, and the entire lower surface thereof is the upper surface of the bottom plate of the device housing. It is stuck to.

Further, a starting point portion 110Q5 is provided at the lower left of the annular structure 110Q, and the intermediate connecting portion 140Q is supported by the first plate-shaped bridge portion 120Q and the second plate-shaped bridge portion 130Q extending from the starting point portion 110Q5. The weight body 150Q is connected to the intermediate connection portion 140Q.

The feature of the modification shown in FIG. 32 is that the fixing portion 110Q is provided with stopper protrusions 110Q6 and 110Q7 protruding in the direction toward the weight body 150Q, and the weight body 150Q accommodates the tip portion of the stopper protrusion. It is at the point where the stopper groove 150QS is provided.

More specifically, in the case of the illustrated example, the stopper protrusion trunk portion 110Q6 protrudes from the starting point portion 110Q5 of the annular structure (fixed portion) 110Q toward the weight body 150Q, and the stopper protrusion A stopper protrusion head 110Q7 is attached to the tip of the trunk 110Q6. Here, the hammer-type structure including the stopper protrusion trunk 110Q6 and the stopper protrusion head 110Q7 is the stopper protrusion, and the weight body 150Q side is capable of accommodating the tip of the stopper protrusion. , The stopper groove 150QS is formed. The tip of the stopper protrusion and the stopper groove 150QS are in a fitted state as shown in the figure, but they are not in close contact with each other, and no external force is applied to the weight body 150Q. In, a predetermined gap is maintained between the outer surface of the tip of the stopper protrusion and the inner surface of the stopper groove 150QS.

With such a stopper structure, even when an excessive acceleration (acceleration that damages each of the plate-shaped bridge portions 120Q and 130Q) is applied to the weight body 150Q, the excessive displacement of each portion can be restricted. As already described in §6-2, it is possible to avoid the situation where the plate-shaped bridge portions 120Q and 130Q are damaged.

In the modified example shown in FIG. 32, the shape of the annular structure 110Q is also slightly modified. That is, the inner shape of the annular structure 110Q is made to match the outer shape of the first plate-shaped bridge portion 120Q, the second plate-shaped bridge portion 130Q, and the intermediate connection portion 140Q, and the gap between the two is a predetermined dimension. Is set to. With this predetermined dimension, when an excessive acceleration acts on the weight body 150Q, the outer surfaces of the first plate-shaped bridge portion 120Q, the second plate-shaped bridge portion 130Q, and the intermediate connecting portion 140Q have an annular structure 110Q. By contacting the inner surface, it is set to an appropriate value to limit excessive displacement of each part.

Therefore, the modified example shown in FIG. 32 is provided with both a displacement control function by the stopper protrusion and a displacement control function by the inner surface of the annular structure 110Q, and the weight body 150Q is provided with these displacement control functions. Even when excessive acceleration is applied, the plate-shaped bridge portions 120Q and 130Q can be protected from damage.

FIG. 33 is a plan view showing another modification of the basic structure 100P shown in FIG. 31. The basic structure 100R shown in FIG. 33 also has a fixed portion composed of a rectangular frame-shaped annular structure 110R having four sides of a left side 110R1, a lower side 110R2, a right side 110R3, and an upper side 110R4, and two in the inner region thereof. The point that the arm portion is provided and the weight body 150R is supported via the intermediate connecting portion 140R is the same as the example shown in FIG. 31. The difference between the two lies in the structure of the two arms.

In the case of the example shown in FIG. 31, two arms are composed of the first plate-shaped bridge portion 120P and the second plate-shaped bridge portion 130P which are curved in a curved line in the intermediate portion, which is shown in FIG. 33. In the case of the example, two arms are formed by an L-shaped plate-shaped bridge portion that is bent at a right angle in the intermediate portion. That is, the first arm has a first plate-shaped tip side bridge portion 121R extending in a direction parallel to the X axis and a first plate-shaped root end side bridge portion 122R extending in a direction parallel to the Y axis. It has a structure combined in a shape, and the second arm has a second plate-shaped tip side bridge portion 131R extending in a direction parallel to the Y axis and a second plate-shaped root end extending in a direction parallel to the X axis. It has a structure in which the side bridge portion 132R and the side bridge portion 132R are combined in an L shape.

Further, FIG. 31 shows the positions of a total of eight upper layer electrodes arranged at both ends of each arm, but FIG. 33 shows the positions of both ends of the first plate-shaped tip side bridge portion 121R. Two pieces each at both ends of the 1-plate-shaped root end side bridge portion 122R, at both ends of the 2nd plate-shaped tip side bridge portion 131R, and at both ends of the 2nd plate-shaped root end side bridge portion 132R (right side electrode and left). The positions of a total of 16 upper-layer electrodes arranged (armpit electrodes) are shown. This is because the middle portion of the arm is bent at a right angle, so that stress is concentrated in the vicinity of this bent portion. Of course, a central electrode may be further arranged at each position, and a total of 24 upper layer electrodes may be provided. Since the characteristics of the generated charge of each upper layer electrode are based on the characteristics of the generated charge of each upper layer electrode of the embodiment shown in FIG. 10 (see the table of FIG. 14), detailed description thereof will be omitted here.

<<< §7. Basic concept of the present invention >>>
Finally, the basic concepts of the present invention, which have been described as various embodiments and modifications thereof, are summarized for each power generation element having a different form of the basic structural portion.

(1) The invention described as the first embodiment in §1 and §2 (two-axis power generation type).
The present invention includes a bridge portion extending along a predetermined longitudinal axis and having flexibility, a weight body connected to one end of the bridge portion, and a device housing for accommodating the bridge portion and the weight body. , A fixing part that fixes the other end of the bridge part to the device housing, a piezoelectric element fixed at a predetermined position on the surface of the bridge part, and a current generated based on the electric charge generated in this piezoelectric element is rectified to generate electric power. It is an invention of a power generation element which is provided with a power generation circuit for taking out and generates power by converting vibration energy into electric energy.

This power generation element is configured so that the weight body vibrates in the device housing due to the bending of the bridge portion when an external force that vibrates the device housing is applied, and the piezoelectric element is a weight on the surface of the bridge portion. It is located at a position where expansion and contraction deformation occurs based on the vibration of the body and is located at a position deviating from the center line along the longitudinal axis, and has a property of generating electric charge based on this expansion and contraction deformation. As described above, the piezoelectric element arranged at a position off the center line has a function of converting both the vertical vibration energy and the horizontal vibration energy of the weight body into electrical energy, and has two axes. Power generation type becomes possible.

(2) The invention described as the second embodiment in §3, §5 (3-axis power generation type).
INDUSTRIAL APPLICABILITY The present invention is directly or indirectly connected to a first bridge portion extending along a first longitudinal axis and having flexibility, directly or indirectly to the first bridge portion, and along a second longitudinal axis. A second bridge portion that is stretchable and flexible, a weight body that is directly or indirectly connected to the second bridge portion, and a first bridge portion, a second bridge portion, and a weight body. A device housing for accommodating the bridge, a fixing portion for fixing one end of the first bridge portion to the device housing, and a piezoelectric element fixed at a predetermined position on the surface of the first bridge portion and the second bridge portion. It is an invention of a power generation element which includes a power generation circuit for rectifying a current generated based on a charge generated in the piezoelectric element and extracting power, and generates power by converting vibration energy into electric energy.

In this power generation element, the fixing portion fixes the root end portion of the first bridge portion to the device housing, and the tip portion of the first bridge portion is directly or indirectly connected to the root end portion of the second bridge portion. It is connected, and a weight body is directly or indirectly connected to the tip of the second bridge portion. The power generation element is configured so that the weight body vibrates in the device housing due to the bending of the first bridge portion and the second bridge portion when an external force that vibrates the device housing acts. The element is arranged on the surface of the first bridge portion and the second bridge portion at a position where expansion and contraction deformation occurs based on the vibration of the weight body, and has a property of generating electric charge based on this expansion and contraction deformation. is doing. In order to perform efficient three-axis power generation, it is preferable that at least a part of the piezoelectric elements are arranged at a position deviating from the center line along the longitudinal axis of each plate-shaped bridge portion.

(3) The invention described as a modification of the second embodiment in §6-3 (both arm support type).
The present invention directly or indirectly to both the flexible first bridge and the flexible second bridge, and the tip of the first bridge and the tip of the second bridge. The weight body connected to the bridge, the device housing for accommodating the first bridge portion, the second bridge portion and the weight body, and the root end portion of the first bridge portion and the root of the second bridge portion. A fixed portion that fixes the end portion to the device housing, a piezoelectric element fixed at a predetermined position on the surface of the first bridge portion and the second bridge portion, and a current generated based on the charge generated in the piezoelectric element. It is an invention of a power generation element that includes a power generation circuit that rectifies and extracts power, and generates power by converting vibration energy into electric energy.

In this power generation element, the root end portion of the first bridge portion and the root end portion of the second bridge portion are connected to the same starting point portion of the fixed portion, and the portion near the tip portion of the first bridge portion. The intermediate portion between the bridge and the portion near the root end is curved or bent, and the intermediate portion between the portion near the tip of the second bridge portion and the portion near the root end is curved or bent. The power generation element is configured so that the weight body vibrates in the device housing due to the bending of the first bridge portion and the second bridge portion when an external force that vibrates the device housing acts. The element is arranged on the surface of the first bridge portion and the second bridge portion at a position where expansion and contraction deformation occurs based on the vibration of the weight body, and has a property of generating electric charge based on this expansion and contraction deformation. is doing. Since the first bridge portion and the second bridge portion are curved or bent in the intermediate portion, various stresses are generated in the portion near the tip portion and the portion near the root end portion, and the vibration energy in various directions is converted into electrical energy. It is effective in converting to. In order to perform efficient three-axis power generation, it is preferable that at least a part of the piezoelectric elements are arranged at a position deviating from the center line along the longitudinal axis of each plate-shaped bridge portion.

(4) In the description and drawings of the present specification so far, the structure, shape, and arrangement of each part have been described using the XYZ three-dimensional coordinate system for convenience. These XYZ three-dimensional coordinate systems are premised on a three-dimensional Cartesian coordinate system in which the X-axis, the Y-axis, and the Z-axis are orthogonal to each other.

However, in carrying out the present invention, the XYZ three-dimensional coordinate system used in the above description does not necessarily have to be a three-dimensional Cartesian coordinate system in which the X-axis, the Y-axis, and the Z-axis are orthogonal to each other. It is also possible to design using a three-dimensional non-Cartesian coordinate system. The three-dimensional non-orthogonal coordinate system referred to here means a three-dimensional coordinate system in which at least the X-axis and the Y-axis are not orthogonal to each other. For example, a coordinate system defined as a coordinate axis where the X-axis and the Y-axis intersect at an arbitrary angle that is not orthogonal to each other and the Z-axis is defined as an axis orthogonal to both the X-axis and the Y-axis is used as a three-dimensional coordinate system. It is possible to make the original design.

The examples described so far using the three-dimensional Cartesian coordinate system have a function of efficiently converting the vibration energy acting in each coordinate axis direction of the three-dimensional Cartesian coordinate system into electrical energy, and are manufactured. Although it has a feature that the process is simplified, the basic concept of the present invention is as described above, and the longitudinal axis of each bridge portion is arbitrary as a power generation element obtained by embodying the basic concept. It doesn't matter if it is in the direction of. For example, in the case of the basic structure shown in FIG. 31, the vicinity of the tip and the root of each bridge so that the central axes L1 to L4 are parallel to the X-axis or the Y-axis in the three-dimensional Cartesian coordinate system. Although the orientation of the vicinity portion is set, the orientations of the central axes L1 to L4 may be different orientations.

Of course, if it is known in advance that the product will be used in a vibration environment facing a specific direction, it is preferable to perform an optimum design for the vibration environment. For example, the power generation element shown in FIG. 1 is optimal for efficiently converting vibration energy in the X-axis direction and vibration energy in the Z-axis direction into electrical energy in a three-dimensional Cartesian coordinate system, and the power generation element shown in FIG. Is optimal for efficiently converting vibrational energy in each coordinate axis direction into electrical energy in a three-dimensional Cartesian coordinate system.

However, in practice, it is difficult to accurately grasp the vibration direction in the environment where the power generation element is mounted. For a general-purpose power generation element, the longitudinal axis of each bridge is set to an arbitrary direction, and this bridge is used. It suffices to arrange an arbitrary number of piezoelectric elements (preferably as many as possible in order to improve power generation efficiency) at any place (preferably a place where stress is concentrated in order to improve power generation efficiency). No matter what polarity of charge is generated in each piezoelectric element, no problem will occur if the electric power is rectified by the power generation circuit and the electric power is taken out.

FIG. 34 is a plan view showing a modified example in which the Cartesian coordinate system in the power generation element shown in FIG. 10 is changed to a non-Orthogonal coordinate system and the central electrodes Ez1 to Ez4 are omitted. For convenience, each part of the modification shown in FIG. 34 is shown using the same reference numerals as those of the embodiment shown in FIG. The functions of the components with the same reference numerals are basically the same, but in the case of the modification shown in FIG. 34, since a non-Cartesian coordinate system is used, the X-axis and the Y-axis are orthogonal to each other. No (Z-axis is perpendicular to the paper). Therefore, the first longitudinal axis Ly defined as an axis parallel to the Y axis and the second longitudinal axis Lx defined as an axis parallel to the X axis do not become axes orthogonal to each other, and the first The arrangement of the plate-shaped bridge portion 120 and the second plate-shaped bridge portion 130 is also oblique. Further, the weight body 150 is also a trapezoidal plate-shaped member. As described above, although the shape of the basic structure is distorted, there is no problem in the basic function as a power generation element.

(5) Various embodiments and modifications thereof have been shown so far, but these embodiments and modifications can be freely combined and used. Although only some combinations of Examples are disclosed in the specification and drawings of the present application, the present invention can be carried out in any combination thereof as long as they do not conflict with each other.

The power generation element according to the present invention can be widely used in a technique for generating power by converting vibration energy into electrical energy. The basic principle is that the vibration of the weight body causes periodic bending of the piezoelectric element, and the electric charge generated based on the stress applied to the piezoelectric element is taken out to the outside. Therefore, automobiles, trains, ships, etc. By attaching it to a vibration source such as a vehicle, refrigerator, or air conditioner, it becomes possible to effectively use the vibration energy that is normally wasted as electrical energy.

10: Fixed part 20: Plate-shaped bridge part 30: Weight body 40: Bottom plate 50, 50B, 50C of device housing: Piezoelectric element 51D, 52D: Piezoelectric element 60: Power generation circuit 70: Fixed part 80: Plate-shaped bridge part 100, 100A to 100R: Basic structure 110, 110AB to 110GH: Plate-shaped member for fixing portion 110I to 110R: Circular structure 110I1 to 110I4: Each side of the annular structure 110J: Circular weight body 110J1 to 110J4: Circular weight Each side of the weight 110K: Annular structure 110K1 to 110K4: Each side of the annular structure 110M1 to 110M4: Auxiliary weights 110N1 to 110N4: Each side of the annular structure 110P1 to 110P4: Each side of the annular structure 110P5: Starting point portion 110Q1 to 110Q4: Each side of the annular structure 110R1 to 110R4: Each side of the annular structure 110N5, 110N6: Stopper protrusion 110Q5: Starting point portion 110Q6, 110Q7: Stopper protrusion 120, 120A to 120Q: First plate-shaped bridge Part 120J: Second plate-shaped bridge part 121P: Tip-near part 121R: First plate-shaped tip-side bridge part 122P: Intermediate part 122R: First plate-shaped root-end-side bridge part 123P: Root-end-near part 125, 125I, 125J, 125K: Intermediate connection part 130, 130A to 130Q: Second plate-shaped bridge part 130J: First plate-shaped bridge part 135K: Intermediate connection part 130P: Second plate-shaped bridge part 130P
131P: Tip portion near portion 131R: Second plate-shaped tip side bridge portion 132P: Intermediate portion 132R: Second plate-shaped root end side bridge portion 133P: Root end portion near portion 140, 140I: Weight connection portion 140J: Fixed end Connection part 140K: Third plate-shaped bridge part 140N: Weight connection part 140P to 140R: Intermediate connection part 145K: Intermediate connection part 150, 150A to 150R: Weight body 150J: Plate-like fixing part 150K: Fourth plate Bridge part 150L: Auxiliary weight body 150NS: Stopper groove 150QS: Stopper groove 160K: Weight connection part 170K: Weight body 200, 200I, 200J: Bottom plate of device housing 300: Piezoelectric element 400: Cover of device housing 410: Top plate of the device housing 420: Side plate of the device housing 500: Power generation circuit 1000: Basic structure of the power generation device 2000: Basic structure of the power generation device Cf: Capacitive element (condenser)
D11 (+) to D13 (+): Positive charge rectifying element (diode)
D11 (-) to D13 (-): Negative charge rectifying element (diode)
D0 (+), Dx1 (+) to Dz24 (+): Positive charge rectifying element (diode)
D0 (-), Dx1 (-) to Dz24 (-): Negative charge rectifying element (diode)
E0, E0B, E0C, E0D, E00: Lower layer electrode E1: Right side electrode E2: Center electrode E3: Left side electrode E10: Right side electrode E20: Left side electrode E11: Right side electrode E12 on the weight body side: Weight body side Center electrode E13: Left side electrode E21, E21B, E21C, E21D on the weight body side: Right side electrode E22, E22B, E22C, E22D on the fixed part side: Center electrode E23, E23B, E23C, E23D on the fixed part side: Fixed Left side electrode E31 on the part side: Right side electrode E32: Center electrode E33: Left side electrode Ex1: Second tip side right side electrode Ex2: Second tip side left side electrode Ex3: Second root end Side right side electrode Ex4: Second root end side left side electrode Ex11: First tip side right side electrode Ex12: First tip side left side electrode Ex13: Second root end side right side electrode Ex14: Second root end side left side electrode Ey1: First tip side right side electrode Ey2: First tip side left side electrode Ey3: First root end side right side electrode Ey4: First Root end side left side electrode Ey11: 1st root end side right side electrode Ey12: 1st root end side left side electrode Ey13: 2nd tip side right side electrode Ey14: 2nd tip Side left side electrode Ez1: Second tip side center electrode Ez2: Second root end side center electrode Ez3: First tip side center electrode Ez4: First root end side center electrode L: Longitudinal direction Axis L0: Longitudinal axis for fixed portion L1: First tip side center line L2: First root end side center line L3: Second tip side center line L4: Second root end side center Line Lx: Second longitudinal axis (center line)
Ly: 1st longitudinal axis (center line)
O: Origins of the three-dimensional coordinate system P11 to P23: Each part of the piezoelectric element 50 Px1 to Pz4: Each part of the piezoelectric element 300 Rd1, Rd2: Resistance element V: Void portion W: Symmetry axis W (Y axis tilted by 45 °) Axis)
X: Coordinate axis Δx (+) of the three-dimensional coordinate system: Displacement in the positive direction of the X axis Y: Coordinate axis Δy (+) of the three-dimensional coordinate system: Displacement in the positive direction of the Y axis Z: Coordinate axis Δz (+) of the three-dimensional coordinate system : Displacement in the positive direction of the Z axis ZL: Load α1 to α3: Eaves structure α11 to α24: Eaves structure

Claims (3)

A power generation element that generates electricity by converting vibration energy in at least one axial direction into electrical energy in each coordinate axis direction in the XYZ three-dimensional coordinate system.
A plate-shaped bridge that is arranged along the XY plane and extends from the root end to the tip along the longitudinal axis parallel to the Y axis.
A weight body connected to the tip of the plate-shaped bridge and
A device housing for accommodating the plate-shaped bridge portion and the weight body, and
A fixing portion for fixing the root end portion of the plate-shaped bridge portion to the device housing, and a fixing portion.
The lower layer electrodes formed in layers on the surface of the plate-shaped bridge, and
Piezoelectric elements formed in layers on the surface of the lower electrode,
The upper layer electrode formed on the surface of the piezoelectric element at a position facing the lower layer electrode and the upper layer electrode.
Equipped with
The plate-shaped bridge portion has flexibility, and when an external force that vibrates the device housing is applied, the weight body is moved in the Z-axis direction in the device housing due to the bending of the plate-shaped bridge portion. Not only is it configured to vibrate in the X-axis direction,
In the fixing portion, the root end portion of the plate-shaped bridge portion is fixed to the device housing, and the weight body is connected to the tip end portion of the plate-shaped bridge portion.
The piezoelectric element has a property of causing polarization in the thickness direction by the action of stress that expands and contracts in the layer direction.
The upper layer electrodes are arranged on the center line of the plate-shaped bridge portion extending in the Y-axis direction from the root end portion to the tip portion of the plate-shaped bridge portion, and the weight body is displaced in the + Z-axis direction. Occasionally, when the upper electrode is charged with the first polarity and the weight is displaced in the −Z axis direction, the upper electrode is charged with the second polarity opposite to the first polarity. A power generation element characterized by the occurrence of. In the power generation element according to claim 1,
A second upper layer electrode formed on the surface of the piezoelectric element at a position facing the lower layer electrode and arranged from the root end portion to the tip end portion of the plate-shaped bridge portion so as to run parallel to the upper layer electrode is further provided. Prepare,
When the second upper electrode is charged with the first polarity when the weight body is displaced in the + X-axis direction, and when the weight body is displaced in the −X-axis direction, the charge is generated. A power generation element characterized in that a charge of the second polarity is generated in a second upper layer electrode. In the power generation element according to claim 2,
It is formed on the surface of the piezoelectric element at a position facing the lower layer electrode, and runs parallel to the upper layer electrode and the second upper layer electrode on the opposite side of the second upper layer electrode with the upper layer electrode interposed therebetween. Further, a third upper layer electrode arranged from the root end portion to the tip end portion of the plate-shaped bridge portion is further provided.
When the third upper electrode is charged with the second polarity when the weight body is displaced in the + X-axis direction, and when the weight body is displaced in the −X-axis direction, the charge is generated. A power generation element characterized in that a charge of the first polarity is generated in a third upper layer electrode.

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