JP2013044610A - Vibration detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration detector capable of easily suppressing power consumption of an apparatus in a stand-by state by a simple structure and of reducing cost by performing vibration detection in X-, Y- and Z-axial directions by one sensor and a circuit of one system.SOLUTION: A vibration detector comprises: a cross-shaped strain element section that has flexibility and conductivity; piezoelectric body sections each two of which are formed on a surface of each beam portion of the strain element section without contact therewith such that a spontaneous polarization direction of each two piezoelectric body sections becomes a predetermined direction preset for generating charge when compression or tension is applied thereto; a fixed frame having the conductivity from/to which a leading end portion of each beam portion is electrically insulated and is fixed; an acceleration sensor 11 that has a weight body section provided on other surface of a central region of the strain element section; charge transferring means 21; an amplifier 12; a reference voltage comparator 13 for outputting a vibration detection signal indicating detection of vibration; and a state switching device 14 that is given with the vibration detection signal and outputs a state switching signal for switching a stand-by state of an apparatus 15 connected to an output terminal to an operational state.

Description

  The present invention relates to a vibration detection device.

  It is necessary to manage the safety of the system using equipment such as a seismometer at a power plant. However, devices such as seismometers require a power source such as a battery. For this reason, if such a device is always in an operating state, power consumption increases. Therefore, it is necessary to set the standby state with power saving as much as possible while it is not operating, and to start the operation only when necessary.

  Therefore, it is required to put the device in a sleep state during standby to reduce power consumption and to start up a state in which earthquake motion can be recorded simultaneously with the occurrence of an earthquake.

  As a method of returning a device such as a seismometer from a standby state to a recording state, there is a technique described in Patent Document 1. This consists of a bimorph-type piezoelectric body that generates an alternating charge in response to an external impact, a storage circuit that rectifies and charges the generated charge, operates with stored power, and the stored voltage becomes a preset voltage. An impact detection sensor having a voltage detection circuit that outputs an external signal, a standby control target part that operates by returning from a standby state by an external signal, and a power source that supplies power to the standby control target part. The target part of the control is to return from the standby state with a shock signal detected by the piezoelectric element unit as a trigger.

  Moreover, there existed what was described in patent document 2 as a technique which detects a vibration. This consists of a flexible disc-shaped strain generating body whose periphery is fixed to a fixed frame, a lower electrode provided on the upper surface of the strain generating body, and a piezoelectric layer laminated on the electrode. A piezoelectric element comprising a ceramic and an upper electrode attached to the surface, and a weight body attached to the center of the lower surface of the strain generating body. The strain generating body detects a strain in the X-axis direction. The device is provided with four sets of piezoelectric elements, ie, a pair of elements for detecting strain in the Y-axis direction and two pairs of elements for detecting strain in the Z-axis direction to detect acceleration in the XYZ-axis directions. is there.

Japanese Patent No. 4272177 JP-A-8-129071

  However, the technique described in Patent Document 1 detects an impact from one direction and returns a standby device to a recording state. Therefore, in order to detect an impact from the three directions of the XYZ axes, three impact detection sensors are required, resulting in a complicated configuration and an increase in cost.

  In the technique described in Patent Document 2, although it is possible to detect earthquake motion in the XYZ axis directions, three detection circuits are necessary, and an increase in cost is inevitable.

  In view of the above circumstances, the present invention performs vibration detection in the X, Y, and Z axis directions with a single sensor and a single system circuit, so that the power consumption of the standby device can be easily suppressed with a simple configuration, and the cost can be reduced. An object is to provide a possible vibration detection device.

A vibration detection device according to an aspect of the present invention includes:
A strain-generating body portion having flexibility and conductivity and having a cross shape including four flat beam portions;
Two pieces are formed on the surface of each of the beam portions of the strain generating body portion so as to be in a non-contact state with each other, and the respective spontaneous polarization directions are formed in a predetermined direction, and are compressed and tensioned. A piezoelectric body that generates an electric charge when applied,
A fixing frame that has conductivity and is fixed in a state where each tip portion of the beam portion of the strain body portion is electrically insulated;
An acceleration sensor having a weight body portion provided on the other surface of the central region to which the four beam portions in the strain body portion are connected;
Charge transmitting means for transmitting the charge generated by the piezoelectric body portion;
An amplifier that receives and amplifies the charge transmitted by the charge transmission means and outputs a voltage signal;
A reference for outputting a vibration detection signal indicating that vibration is detected when the voltage signal output from the amplifier is compared with a reference voltage and the voltage signal is equal to or higher than the reference voltage or higher than the reference voltage. A voltage comparator;
A state switching device that is provided with the vibration detection signal output from the reference voltage comparator and outputs a state switching signal for switching the standby state of the device connected to the output terminal to an operating state;
It is provided with.

  According to the vibration detection device of the present invention, by performing vibration detection in the XYZ axial directions with one acceleration sensor and one system circuit, it is possible to easily suppress the power consumption of the standby device with a simple configuration, Cost reduction is realized.

The block diagram which shows the structure of the vibration detection apparatus by the 1st-3rd embodiment of this invention. The top view which shows the structure of the acceleration sensor in the vibration detection apparatus. The side view which shows the structure of the acceleration sensor in the vibration detection apparatus. The side view which shows operation | movement when detecting the Z-axis direction acceleration in the acceleration sensor of the vibration detection apparatus. The side view which shows operation | movement when detecting the X-axis or Y-axis direction acceleration in the acceleration sensor of the vibration detection apparatus. The top view which shows the connection structure in the acceleration sensor of the vibration detection apparatus by the 1st Embodiment of this invention. Explanatory drawing which shows the electrical signal output ratio obtained by the connection structure in the acceleration sensor of the vibration detection apparatus by said 1st Embodiment. The top view which shows the connection structure in the acceleration sensor of the vibration detection apparatus by the 2nd Embodiment of this invention. Explanatory drawing which shows the electrical signal output ratio obtained by the connection structure in the acceleration sensor of the vibration detection apparatus by the said 2nd Embodiment. The top view which shows the connection structure in the acceleration sensor of the vibration detection apparatus by the 3rd Embodiment of this invention. Explanatory drawing which shows the electrical signal output ratio obtained by the connection structure in the acceleration sensor of the vibration detection apparatus by the 3rd Embodiment.

  Hereinafter, a vibration detection apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration of a vibration detection device 10 according to first to third embodiments described later, and a device 15 such as a seismometer connected to the vibration detection device 10.

  The vibration detection device 10 includes an acceleration sensor 11, an amplifier 12, a reference voltage comparator 13, and a state switching device 14.

  The acceleration sensor 11 has a configuration to be described later, and generates electric charges when an acceleration is applied due to vibration caused by an earthquake or the like. This charge is given to the amplifier 12 as a current signal via the charge transfer means 21. The amplifier 12 amplifies the supplied current signal and outputs a voltage signal to the reference voltage comparator 13.

  The reference voltage comparator 13 is supplied with the voltage signal output from the amplifier 12 and a preset reference voltage and compares them, and when the voltage signal exceeds the reference voltage or exceeds the reference voltage, the vibration detection signal Is output. In other words, when the magnitude of the acceleration applied to the acceleration sensor 11 is greater than or equal to a preset threshold value or exceeds the threshold value, a vibration detection signal indicating that a predetermined level of vibration has been detected is output to the state switching device 14. Here, in the output from the acceleration sensor 11, the output ratio between the maximum value and the minimum value has a difference of about 4 to 5 times, for example. Therefore, a threshold value may be set corresponding to the minimum output value.

  The state switching device 14 is connected to the device 15, and when receiving a vibration detection signal from the reference voltage comparator 13, the state switching device 14 switches the standby device 15 to an operation state in which, for example, earthquake recording is possible.

  As a specific example, for example, BU7265G (Rohm: registered trademark) or the like may be used as the amplifier 12, and LTC1540 (Linear Technology: registered trademark) or the like may be used as the reference voltage comparator 6. Can be reduced to 1 μA or less. As the state switching device 14, a microcomputer such as MSP430 series (Texas Instruments: registered trademark) or nanoWatt XLP (Microchip Technology: registered trademark) may be used.

  By providing such a configuration, according to the vibration detection apparatus according to the first to third embodiments, vibration due to an earthquake or the like is detected, and a vibration value having a magnitude set in advance in consideration of vibration intensity is obtained. When it arrives, the apparatus in a standby state can be returned to an operation state such as a recording state in order to reduce power consumption.

  Below, the concrete structure of each acceleration sensor 11 in the vibration detection apparatus 10 by the 1st-3rd embodiment is demonstrated.

(1) 1st Embodiment The structure of the acceleration sensor 11 of the vibration detection apparatus 10 by the 1st Embodiment of this invention is demonstrated with reference to FIGS.

  FIG. 2 shows a planar configuration of the acceleration sensor 11, and FIG. 3 shows a configuration viewed from the side.

  The acceleration sensor 11 is made of a conductive material and has a rectangular frame as shown in the center, and a cross frame including four flat beams made of a flexible conductive material. Shape-shaped strain body portion 2, piezoelectric body portions 3a to 3h formed in a predetermined region on one surface (upper surface in the drawing) of strain body portion 2, and four beams in strain body portion 2 And a weight body portion 4 provided on the other surface (lower surface in the drawing) of the central region where the portions intersect.

  The strain generating body portion 2 is formed of, for example, a 42 alloy material having a linear expansion coefficient close to that of ceramics. The piezoelectric body portions 3a to 3h are formed of a piezoelectric ceramic material such as a lead zirconate titanate (PZT) material or a barium titanate material.

  On the beam portion along the X-axis direction of the strain generating body portion 2, piezoelectric body portions 3a and 3b are formed from the left side to the central region in the drawing, and piezoelectric body portions 3c and 3d are formed from the central region to the right side. On the beam portion along the Y-axis direction of the strain body portion 2, piezoelectric body portions 3e and 3f are formed from the upper side to the central region in the drawing, and piezoelectric body portions 3g and 3h are formed from the central region to the lower side. .

  As a method of forming the piezoelectric body portions 3a to 3h on one surface of the strain generating body portion 2, for example, bonding may be performed using an adhesive whose main component is alumina or silica whose linear expansion coefficient is close to ceramics. Good.

  FIG. 4 shows a state when acceleration is applied to the acceleration sensor 11 downward in the Z-axis direction. Strain is generated in the strain generating body portion 2, and tensile or compression is applied to the piezoelectric body portions 3 a, 3 b, 3 c, 3 d arranged in the X-axis direction to generate electric charges. Similarly, tension or compression is applied to the piezoelectric portions 3e, 3f, 3g, and 3h arranged in the Y-axis direction to generate electric charges. When acceleration is applied upward in the Z-axis direction, the tension and compression generated in each of the piezoelectric body portions 3a to 3h are switched, and the polarity of the charges is reversed.

  FIG. 5 shows a state when acceleration is applied to the acceleration sensor 11 in the X-axis direction in the right direction in the figure. Strain is generated in the strain generating body portion 2, and tensile or compression is applied to the piezoelectric body portions 3 a, 3 b, 3 c, 3 d arranged in the X-axis direction to generate electric charges. When acceleration is applied to the left in the figure in the X-axis direction, tension and compression are switched, and the polarity of the charge is reversed. However, the piezoelectric parts 3e, 3f, 3g, and 3h arranged in the Y-axis direction are not tensioned or compressed and no charge is generated.

  FIG. 6 shows a configuration in which the piezoelectric body portions 3 a to 3 h are connected by the charge transfer means 21 in the acceleration sensor 11 according to the first embodiment. The strain body 2 is connected to the ground terminal GND and grounded. Of the piezoelectric body portions 3a to 3h, the piezoelectric body portions 3a and 3b are interconnected in parallel, the piezoelectric body portions 3c and 3d are interconnected in parallel, and the piezoelectric body portions 3g and 3h are interconnected in parallel. The piezoelectric body portion 3e and the output terminal OUT are connected, and in parallel therewith, the piezoelectric body portions 3a and 3b, the piezoelectric body portions 3c and 3d, and the piezoelectric body portions 3g and 3h are connected to the output terminal OUT.

  The piezoelectric body portion 3f is not connected, and corresponds to a dummy piezoelectric body portion in the first embodiment. Thus, by forming all the piezoelectric body portions 3 a to 3 h on the strain generating body portion 2 and changing only the connection configuration by the charge transfer means 21, the cost can be reduced.

  Here, each of the piezoelectric body portions 3a to 3h has a piezoelectric polarity (spontaneous polarization direction). In the first embodiment, the piezoelectric polarities of the piezoelectric portions 3a and 3h and the piezoelectric polarities of the other piezoelectric portions 3b, 3c, 3d, 3e, 3f, and 3g are reversed.

  That is, in the first embodiment, the piezoelectric parts 3a and 3h, or the piezoelectric parts 3d and 3h, or the piezoelectric parts 3d and 3e, or the piezoelectric parts 3a and 3e have other piezoelectric polarities. Disposed differently from the piezoelectric body portion, and other piezoelectric body portions except for any one of the piezoelectric body portions 3b, 3c, 3f, and 3g are connected in parallel to the output terminal O, respectively, and the strain generating body portion 2 is grounded.

  When accelerations of the same magnitude are applied in the XYZ axis directions to the acceleration sensor 11 to which the piezoelectric body portions 3a to 3h are connected in this way, an output ratio having the polarity shown in FIG. 7 is obtained. This polarity corresponds to compression when one is tensile. When the direction of vibration is changed and tension and compression are switched, the polarity of the output is reversed.

  When acceleration is applied in the X-axis direction, tension or compression is applied to the piezoelectric portions 3b and 3d to generate electric charges, and electric charges are generated to be applied to the piezoelectric portions 3a and 3c to generate electric charges. No charge is generated in 3g and 3h. Here, the piezoelectric body part 3a has the piezoelectric polarity inverted, and the output is inverted. The output coefficient in this case is 1, and the total output ratio is −2.

  When acceleration is applied in the Y-axis direction, tension or compression is applied to the piezoelectric body portions 3e and 3g to generate charges, and compression or tension is applied to the piezoelectric body portions 3h to generate charges, and the piezoelectric body portions 3a and 3b. No charge is generated in 3c and 3d. Here, the piezoelectric body portion 3h has the piezoelectric polarity inverted, and the output is inverted. In this case, the output coefficient is 1, and the total output ratio is 3.

  When acceleration is applied in the Z-axis direction, a charge is generated by applying tension or compression to the piezoelectric parts 3b, 3c, and 3g, and a charge is generated by applying compression or tension to the piezoelectric parts 3a, 3d, 3e, and 3h. Arise. Here, the piezoelectric polarities of the piezoelectric parts 3a and 3h are inverted, and the output is inverted. In this case, the output coefficient is 1, and the total output ratio is 3.

  When acceleration is applied in the XY-axis direction, tension or compression is applied to the piezoelectric parts 3a, 3c, and 3h to generate charges, and compression or tension is applied to the piezoelectric parts 3b, 3d, 3e, and 3g to generate charges. Arise. Here, the piezoelectric polarities of the piezoelectric parts 3a and 3h are inverted, and the output is inverted. In this case, when acceleration is applied in the XY-axis direction, distortion is suppressed compared to when acceleration is applied only in the X-axis direction, only in the Y-axis direction, and only in the Z-axis direction. The output ratio is 0.7, and the total value multiplied by 0.7 is -3.5.

  When acceleration is applied in the YX-axis direction, tension or compression is applied to the piezoelectric parts 3b, 3d, and 3h to generate charges, and compression or tension is applied to the piezoelectric parts 3a, 3c, 3e, and 3g to generate charges. Arise. Here, the piezoelectric polarities of the piezoelectric parts 3a and 3h are inverted, and the output is inverted. In this case as well, as in the case where acceleration is applied in the XY-axis direction, the output coefficient is 0.7, and the output ratio obtained by multiplying the total value by 0.7 is −0.7.

  As described above, according to the first embodiment, a single circuit having the acceleration sensor 11, the amplifier 12, the reference voltage comparator 13, and the state switching device 14 detects vibration in the three directions of the XYZ axes. In addition, by realizing the circuit with one system, it is possible to easily switch the standby device 15 to the operating state with a simple configuration, and it is possible to reduce the power consumption of the device and reduce the cost.

(2) 2nd Embodiment The structure of the acceleration sensor 11 of the vibration detection apparatus 10 by the 2nd Embodiment of this invention is demonstrated with reference to FIGS.

  The configuration of the acceleration sensor 11 is the same as that of the second embodiment, and a description thereof is omitted. The second embodiment is different from the first embodiment in the connection configuration of the piezoelectric body portions 3a to 3h in the acceleration sensor 11, and is as shown in FIG.

  The strain body 2 is connected to the ground terminal GND and grounded. Of the piezoelectric body portions 3a to 3h, the piezoelectric body portions 3a and 3b are interconnected in parallel, and the piezoelectric body portions 3c and 3d are interconnected in parallel. The piezoelectric body portion 3h and the output terminal OUT are connected, and in parallel therewith, the piezoelectric body portions 3a and 3b and the piezoelectric body portions 3c and 3d are connected and connected to the output terminal OUT. The piezoelectric body portions 3e, 3f, and 3g are not connected and correspond to dummy piezoelectric body portions. In the second embodiment, the piezoelectric polarities of the piezoelectric body portions 3a and 3h and the piezoelectric polarities of the other piezoelectric body portions 3b, 3c, 3d, 3e, 3f, and 3g are reversed.

  That is, in the second embodiment, the piezoelectric body portions 3a and 3h, or the piezoelectric body portions 3d and 3h, or the piezoelectric body portions 3d and 3e, or the piezoelectric body portions 3a and 3e have other piezoelectric polarities. It is arranged differently from the piezoelectric body portion, and further, the first group consisting of the piezoelectric body portions 3a, 3b and 3c, or the second group consisting of the piezoelectric body portions 3b, 3c and 3d, or the piezoelectric body portions 3e and 3f. And a third group consisting of 3g, or a fourth group consisting of piezoelectric body portions 3f, 3g and 3h, and arranged so that the piezoelectric polarity is different from other piezoelectric body portions. The other piezoelectric parts excluding the group not included are connected in parallel to the output terminal O, and the strain generating part 2 is grounded.

  When accelerations of the same magnitude are applied in the XYZ axis directions to the acceleration sensor 11 to which the piezoelectric body portions 3a to 3h are connected in this way, an output ratio having the polarity shown in FIG. 9 is obtained. This polarity corresponds to compression when one is tensile.

  When acceleration is applied in the X-axis direction, tension or compression is applied to the piezoelectric parts 3a and 3c to generate electric charges, and electric charges are generated to be applied to the piezoelectric parts 3b and 3d to generate electric charges. No charge is generated. Here, the piezoelectric polarities of the piezoelectric parts 3a and 3h are inverted, and the output is inverted. The output coefficient in this case is 1, and the total output ratio is −2.

  When acceleration is applied in the Y-axis direction, tension or compression is applied to the piezoelectric body portion 3h and charges are generated, and no charges are generated in the piezoelectric body portions 3a, 3b, 3c, and 3d. Here, the piezoelectric body portion 3h has the piezoelectric polarity inverted, and the output is inverted. In this case, the output coefficient is 1, and the total output ratio is 1.

  When acceleration is applied in the Z-axis direction, tension or compression is applied to the piezoelectric portions 3b and 3c to generate charges, and compression or tension is applied to the piezoelectric portions 3a, 3d and 3h to generate charges. In this case, the output coefficient is 1, and the total output ratio is 3.

  When acceleration is applied in the XY-axis direction, tension or compression is applied to the piezoelectric body portions 3a, 3c, and 3h to generate charges, and compression or tension is applied to the piezoelectric body portions 3b and 3d to generate charges. Here, the piezoelectric polarities of the piezoelectric parts 3a and 3h are inverted, and the output is inverted. The output coefficient in this case is 0.7, and the output ratio obtained by multiplying the total value by 0.7 is −2.1.

  When acceleration is applied in the YX-axis direction, tension or compression is applied to the piezoelectric body portions 3b, 3d, and 3h to generate charges, and compression or tension is applied to the piezoelectric body portions 3a and 3c to generate charges. Here, the piezoelectric polarities of the piezoelectric parts 3a and 3h are inverted, and the output is inverted. The output coefficient in this case is 0.7, and the output ratio obtained by multiplying the total value by 0.7 is 0.7.

  As described above, according to the second embodiment, a single circuit having the acceleration sensor 11, the amplifier 12, the reference voltage comparator 13, and the state switching device 14 can detect vibrations in the three directions of the XYZ axes. In addition, by realizing the circuit with one system, it is possible to easily switch the standby device 15 to the operating state with a simple configuration, and it is possible to reduce the power consumption of the device and reduce the cost.

(3) 3rd Embodiment The structure of the acceleration sensor 11 of the vibration detection apparatus 10 by the 3rd Embodiment of this invention is demonstrated with reference to FIGS.

  As will be described later, the configuration of the acceleration sensor 11 is the same as that of the first and second embodiments except that the arrangement of the piezoelectric polarity is different. The connection configuration of the piezoelectric body portions 3a to 3h in the acceleration sensor 11 according to the third embodiment is as shown in FIG.

  The strain body 2 is connected to the ground terminal GND and grounded. Of the piezoelectric body portions 3a to 3h, the piezoelectric body portions 3a and 3b are interconnected in parallel, and the piezoelectric body portions 3c and 3d are interconnected in parallel. The piezoelectric body portion 3e and the output terminal OUT are connected, and in parallel therewith, the piezoelectric body portions 3a and 3b and the piezoelectric body portions 3c and 3d are connected and connected to the output terminal OUT. The piezoelectric body portions 3f, 3g, and 3h are not connected and correspond to dummy piezoelectric body portions. In the third embodiment, the piezoelectric polarity of the piezoelectric body portion 3a and the piezoelectric polarities of the other piezoelectric body portions 3b, 3c, 3d, 3e, 3f, 3g, and 3h are reversed.

  That is, in the third embodiment, the piezoelectric polarity of any one of the piezoelectric body portions 3a, 3h, 3d, or 3e is different from that of the other piezoelectric body portions, and the piezoelectric body portion 3a. From the first group consisting of 3b and 3c, or from the second group consisting of piezoelectric parts 3b, 3c and 3d, or from the third group consisting of piezoelectric parts 3e, 3f and 3g, or from piezoelectric parts 3f, 3g and 3h The other piezoelectric body portions excluding the group that is any one of the fourth group and that does not include those that are arranged so that the piezoelectric polarity is different from the other piezoelectric body portions are in parallel with the output terminal O, respectively. The strain generating body 2 is connected and grounded.

  When accelerations of the same magnitude are applied in the XYZ axis directions to the acceleration sensor 11 to which the piezoelectric body portions 3a to 3h are connected in this way, an output ratio having the polarity shown in FIG. 11 is obtained. This polarity corresponds to compression when one is tensile.

  When acceleration is applied in the X-axis direction, tension or compression is applied to the piezoelectric body portions 3a and 3c to generate electric charges, and electric charges are generated to compress or tension the piezoelectric body portions 3b and 3d to generate piezoelectric body portions 3e. No charge is generated. Here, the piezoelectric polarity of the piezoelectric part 3a is inverted, and the output is inverted. The output coefficient in this case is 1, and the total output ratio is −2.

  When acceleration is applied in the Y-axis direction, tension or compression is applied to the piezoelectric body portion 3e to generate charges, and no charge is generated to the piezoelectric body portions 3a, 3b, 3c, and 3d. In this case, the output coefficient is 1, and the total output ratio is 1.

  When acceleration is applied in the Z-axis direction, tension or compression is applied to the piezoelectric portions 3b and 3c to generate electric charges, and electric charges are generated to be applied to the piezoelectric portions 3a, 3d and 3e. Here, the piezoelectric polarity of the piezoelectric part 3a is inverted, and the output is inverted. In this case, the output coefficient is 1, and the total output ratio is 1.

  When acceleration is applied in the XY axis direction, tension or compression is applied to the piezoelectric body portions 3a and 3c to generate charges, and compression or tension is applied to the piezoelectric body portions 3b, 3d and 3e to generate charges. Here, the piezoelectric polarity of the piezoelectric part 3a is inverted, and the output is inverted. The output coefficient in this case is 0.7, and the output ratio obtained by multiplying the total value by 0.7 is −2.1.

  When acceleration is applied in the YX-axis direction, tension or compression is applied to the piezoelectric parts 3b and 3d to generate charges, and compression or tension is applied to the piezoelectric parts 3a, 3c and 3e to generate charges. Here, the piezoelectric polarity of the piezoelectric part 3a is inverted, and the output is inverted. The output coefficient in this case is 0.7, and the output ratio obtained by multiplying the total value by 0.7 is 0.7.

  As described above, according to the third embodiment, the vibration detection in the three directions of the XYZ axes is performed by a single circuit having one acceleration sensor 11, the amplifier 12, the reference voltage comparator 13, and the state switching device 14. In addition, by realizing the circuit with one system, it is possible to easily switch the standby device 15 to the operating state with a simple configuration, and it is possible to reduce the power consumption of the device and reduce the cost.

  Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the technical scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the technical scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  For example, the connection configuration of the piezoelectric body portions in the acceleration sensor 11 is not limited to those described in FIGS. 6, 8, and 10, and the piezoelectric body portions 3a, 3b, 3c, and 3d arranged in the first direction. At least one of the piezoelectric bodies 3e, 3f, 3g, 3h arranged in the second direction orthogonal to the first direction is connected in parallel to the output terminal OUT If it is.

DESCRIPTION OF SYMBOLS 1 Fixed frame 2 Strain body part 3 Piezoelectric body part 4 Weight body part 10 Vibration detection apparatus 11 Acceleration sensor 12 Amplifier 13 Reference voltage comparator 14 State switching apparatus 15 Equipment 21 Charge transmission means

Claims (7)

A strain-generating body portion having flexibility and conductivity and having a cross shape including four flat beam portions;
Two pieces are formed on the surface of each of the beam portions of the strain generating body portion so as to be in a non-contact state with each other, and the respective spontaneous polarization directions are formed in a predetermined direction, and are compressed and tensioned. A piezoelectric body that generates an electric charge when applied,
A fixing frame that has conductivity and is fixed in a state where each tip portion of the beam portion of the strain body portion is electrically insulated;
An acceleration sensor having a weight body portion provided on the other surface of the central region to which the four beam portions in the strain body portion are connected;
Charge transmitting means for transmitting the charge generated by the piezoelectric body portion;
An amplifier that receives and amplifies the charge transmitted by the charge transmission means and outputs a voltage signal;
A reference for outputting a vibration detection signal indicating that vibration is detected when the voltage signal output from the amplifier is compared with a reference voltage and the voltage signal is equal to or higher than the reference voltage or higher than the reference voltage. A voltage comparator;
A state switching device that is provided with the vibration detection signal output from the reference voltage comparator and outputs a state switching signal for switching the standby state of the device connected to the output terminal to an operating state;
A vibration detection apparatus comprising:   The vibration detection device according to claim 1, wherein the strain body portion is formed using a 42 alloy material.   The vibration detecting apparatus according to claim 1, wherein the piezoelectric body portion is formed using a lead zirconate titanate material. As the four beam portions, there are a first beam portion and a second beam portion at both ends of the central region along the first direction, and a second direction orthogonal to the first direction. A third beam portion and a fourth beam portion at both ends of the central region along
As the piezoelectric portion, the first piezoelectric portion and the second piezoelectric portion are provided on one surface of the first beam portion from the fixed frame toward the central region. On one surface of the beam portion, there is a third piezoelectric portion and a fourth piezoelectric portion from the central region toward the fixed frame, and on one surface of the third beam portion. , Having a fifth piezoelectric portion and a sixth piezoelectric portion from the fixed frame toward the central region, on one surface of the fourth beam portion, from the central region to the fixed frame Toward, it has a seventh piezoelectric part, an eighth piezoelectric part,
The charge transfer means includes at least one of the first piezoelectric portion, the second piezoelectric portion, the third piezoelectric portion, and the fourth piezoelectric portion, and the fifth piezoelectric portion. And at least one of a body part, the sixth piezoelectric part, the seventh piezoelectric part, and the eighth piezoelectric part connected in parallel to an input terminal of the amplifier. The vibration detection apparatus according to any one of claims 1 to 3. As the four beam portions, there are a first beam portion and a second beam portion at both ends of the central region along the first direction, and a second direction orthogonal to the first direction. A third beam portion and a fourth beam portion at both ends of the central region along
As the piezoelectric portion, the first piezoelectric portion and the second piezoelectric portion are provided on one surface of the first beam portion from the fixed frame toward the central region. On one surface of the beam portion, there is a third piezoelectric portion and a fourth piezoelectric portion from the central region toward the fixed frame, and on one surface of the third beam portion. , Having a fifth piezoelectric portion and a sixth piezoelectric portion from the fixed frame toward the central region, on one surface of the fourth beam portion, from the central region to the fixed frame Toward, it has a seventh piezoelectric part, an eighth piezoelectric part,
The first piezoelectric member and the eighth piezoelectric member, the fourth piezoelectric member and the eighth piezoelectric member, the fourth piezoelectric member and the fifth piezoelectric member, or The piezoelectric polarity of any one of the first piezoelectric part and the fifth piezoelectric part is arranged to be different from the other piezoelectric parts,
The charge transfer means includes the other piezoelectric body portions excluding any one of the second piezoelectric body portion, the third piezoelectric body portion, the sixth piezoelectric body portion, and the seventh piezoelectric voltage portion. The vibration detecting device according to any one of claims 1 to 3, wherein each of the first and second amplifiers is connected in parallel to the input terminal of the amplifier, and the strain generating body portion is grounded. As the four beam portions, there are a first beam portion and a second beam portion at both ends of the central region along the first direction, and a second direction orthogonal to the first direction. A third beam portion and a fourth beam portion at both ends of the central region along
As the piezoelectric portion, the first piezoelectric portion and the second piezoelectric portion are provided on one surface of the first beam portion from the fixed frame toward the central region. On one surface of the beam portion, there is a third piezoelectric portion and a fourth piezoelectric portion from the central region toward the fixed frame, and on one surface of the third beam portion. , Having a fifth piezoelectric portion and a sixth piezoelectric portion from the fixed frame toward the central region, on one surface of the fourth beam portion, from the central region to the fixed frame Toward, it has a seventh piezoelectric part, an eighth piezoelectric part,
The first piezoelectric member and the eighth piezoelectric member, the fourth piezoelectric member and the eighth piezoelectric member, the fourth piezoelectric member and the fifth piezoelectric member, or The piezoelectric polarity of any one of the first piezoelectric part and the fifth piezoelectric part is arranged to be different from the other piezoelectric parts,
The charge transfer means may be a first group consisting of the first piezoelectric body portion, the second piezoelectric body portion, and the third piezoelectric body portion, or the second piezoelectric body portion, the third piezoelectric body. And the second group consisting of the fourth piezoelectric part, or the third group consisting of the fifth piezoelectric part, the sixth piezoelectric part and the seventh piezoelectric part, or the sixth group. It is one group of the fourth group consisting of a piezoelectric part, the seventh piezoelectric part and the eighth piezoelectric part, and is arranged so that the piezoelectric polarity is different from the other piezoelectric parts. 4. The piezoelectric body portion other than a group not including a slab is connected in parallel to an input terminal of the amplifier, and the strain generating body portion is grounded. The vibration detection device described in 1. As the four beam portions, there are a first beam portion and a second beam portion at both ends of the central region along the first direction, and a second direction orthogonal to the first direction. A third beam portion and a fourth beam portion at both ends of the central region along
As the piezoelectric portion, the first piezoelectric portion and the second piezoelectric portion are provided on one surface of the first beam portion from the fixed frame toward the central region. On one surface of the beam portion, there is a third piezoelectric portion and a fourth piezoelectric portion from the central region toward the fixed frame, and on one surface of the third beam portion. , Having a fifth piezoelectric portion and a sixth piezoelectric portion from the fixed frame toward the central region, on one surface of the fourth beam portion, from the central region to the fixed frame Toward, it has a seventh piezoelectric part, an eighth piezoelectric part,
The piezoelectric polarity of any one of the first piezoelectric part, the fourth piezoelectric part, the fifth piezoelectric part, or the eighth piezoelectric part is different from the other piezoelectric parts. Arranged,
The charge transfer means may be a first group consisting of the first piezoelectric body portion, the second piezoelectric body portion, and the third piezoelectric body portion, or the second piezoelectric body portion, the third piezoelectric body. And the second group consisting of the fourth piezoelectric part, or the third group consisting of the fifth piezoelectric part, the sixth piezoelectric part and the seventh piezoelectric part, or the sixth group. It is one group of the fourth group consisting of a piezoelectric part, the seventh piezoelectric part and the eighth piezoelectric part, and is arranged so that the piezoelectric polarity is different from the other piezoelectric parts. 4. The piezoelectric body portion other than a group not including a slab is connected in parallel to an input terminal of the amplifier, and the strain generating body portion is grounded. The vibration detection device described in 1.

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