JPH09280942A - Multi-directional vibration detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a detection of horizontal and vertical vibrations (vertical sway) in all directions with only one detector. SOLUTION: There are arranged a concave curved case 1 comprising a non-magnetic body, a magnetic body 2 movably housed freely in the case according to gravity, a coil 3 set on the undersurface of the case and a permanent magnet 4 exerting a magnetic field to the coil to measure an induced electromotive force in the coil. Otherwise, the inductance of the coil 3 is measured omitting the magnet 4. When vibration is applied vertically or horizontally on the case 1 from outside, the magnetic body 2 moves relatively in the case 1 and the relative position of the magnetic body 2 changes with respect to the coil 3. Thus, the induced electromotive force is generated in the coil 3 or the inductance changes according to the variations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting lateral and vertical (vertical) multidirectional vibrations such as seismic motion, and a device for detecting an accelerating impact from an arbitrary direction. .

[0002]

2. Description of the Related Art An electrodynamic vibration sensor is known which detects vibration by converting mechanical vibration into an electric signal by the principle opposite to that of a voice coil of a speaker. A piezoelectric vibration sensor is known to detect mechanical strain applied to a piezoelectric element as vibration.

[0003]

Conventionally known electrodynamic vibration sensors use a spring to exclusively pick up vibrations in one direction, and complex vibrations in multiple lateral and vertical directions such as seismic motions. The phenomenon could not be detected. On the other hand, since the piezoelectric vibration sensor uses a piezoelectric element itself as a spring element, it has a high natural frequency and is hardly damped. Therefore, it is completely unsuitable for vibration detection such as earthquake motion. The present invention has been made in view of the above-mentioned points, and in response to a complicated vibration phenomenon in multiple directions, such as an arbitrary lateral sway such as seismic motion or vertical sway, a single detection device, An object of the present invention is to provide a multidirectional vibration detection device capable of detecting this. Furthermore, the present invention is intended to provide a multidirectional vibration detection device suitable for detecting an accelerating impact from an arbitrary direction.

[0004]

A multidirectional vibration detecting device according to the present invention includes a case having a concave curved surface made of a non-magnetic material, a magnetic material housed in the case so as to be movable according to gravity, and the case. A coil installed on the lower surface of the magnet, and a magnet that exerts a magnetic field on the coil, and the magnetic body moves in the case in response to vibration in an arbitrary direction externally applied to the case, and accordingly The relative position of the magnetic body with respect to the coil varies, and the vibration is detected by measuring an induced electromotive force generated in the coil according to the variation.

Since the magnetic body is housed movably according to gravity in a concave curved case made of a non-magnetic body, the magnetic body is relatively moved in response to a multidirectional vibration applied to the case from the outside. Laterally or vertically,
Move freely in multiple directions. Here, since the case has a concave curved surface shape, when it is in a non-vibration neutral state, the magnetic body naturally settles to a predetermined lowermost position of the case due to its own weight. Since the relative position of the magnetic body with respect to the coil changes in response to the relative multidirectional movement of the magnetic body in response to the vibration in any direction of the case, an induced electromotive force is generated from the coil according to this change. Therefore, it is possible to detect vibration in multiple directions by measuring the induced electromotive force generated in the coil. It should be noted that in order to analyze the detected vibration response waveform signal and analyze the required seismic wave, a known seismic wave signal analysis technique may be appropriately used. That is, it is known that different vibration characteristics are exhibited depending on the vertical wave or the transverse wave. Therefore, by analyzing the vibration detection signal obtained by the multidirectional vibration detection device of the present invention, the vertical wave or It is possible to analyze required seismic waves such as transverse waves. Therefore, according to the present invention, both vertical and lateral vibrations can be detected by a single detection device,
Since a multi-directional vibration detection device is provided, seismic wave detection,
It is most suitable as a sensor for analysis and analysis.

The present invention is not limited to the electromotive force type as described above, but may be of a type that measures the inductance of the coil. That is, according to another aspect, a multi-directional vibration detection device of the present invention includes a case having a concave curved surface made of a non-magnetic material, a magnetic material housed in the case movably according to gravity, and A coil installed on the lower surface and a circuit for measuring the inductance of the coil are provided, and the magnetic body moves in the case in response to vibration in an arbitrary direction applied to the case from the outside, and accordingly, the magnetic body moves. The relative position of the magnetic body with respect to the coil fluctuates, and the vibration is detected by measuring an inductance change of the coil according to the fluctuation. In this case as well, similarly to the above, the relative position of the magnetic body with respect to the coil changes in accordance with the relative multidirectional movement of the magnetic body in response to the vibration of the case in any direction. Since the inductance of the coil changes according to this variation, it is possible to detect vibration in multiple directions by measuring the inductance of the coil.

The magnetic body may be a rigid sphere. Alternatively, the magnetic body may be composed of a magnetic fluid. Alternatively, the magnetic body may be made of magnetic powder. By appropriately selecting the mass of the magnetic body, it is possible to select the response characteristic to vibration-for example, it does not respond to small vibrations,
Since it can be made to respond to a slow and large vibration, it can be made to have a resonance characteristic for a desired seismic wave. Therefore, it is possible to cancel the noise-like vibration in the light of the purpose of detection (for example, seismic wave detection) and obtain a detection signal that responds better to the desired seismic wave vibration. A plurality of the coils are two-dimensionally arranged on the lower surface of the case, and the induced electromotive force or the inductance of each coil is individually measured.
You may make it detect multidirectional vibration based on those combinations. Then, the accuracy will be further improved.

The multi-directional vibration detecting device according to the present invention comprises a concave curved surface case made of a non-magnetic material, a magnetic material housed in the case so as to be movable in accordance with gravity, and a predetermined range of the curved surface of the case. A plurality of coil parts installed, and the magnetic body moves in the case in response to an impact in an arbitrary direction applied to the case from the outside, and accordingly, the magnetic body moves with respect to the coil parts. The relative position fluctuates, and the direction of the impact is detected based on the output generated from any one of the coil portions according to the fluctuation. This makes it possible to detect the direction of vibration, that is, the impact, depending on which coil produces the output, and it is possible to detect the accelerating impact from any direction.

[0009]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic vertical cross-sectional view showing an embodiment of the multidirectional vibration detection device of the present invention. The concave curved case 1 made of a non-magnetic material has a semi-spherical shape like a bowl, for example. The top of the case 1 may be covered or covered as appropriate. This case 1
Inside, a steel ball 2 made of a magnetic material such as iron is housed, and the steel ball 2 is movable in the case 1 according to gravity. One coil 3 is fixedly or semi-fixedly installed to the case 1 on the outer lower surface of the case 1. A permanent magnet 4 is fixedly or semi-fixedly arranged below the coil 3, and a magnetic field is exerted so that the magnetic flux penetrates the ring space of the coil 3. In this way, the case 1, the coil 3 and the permanent magnet 4 are integrated, and the steel ball 2 can move freely relative to the case 1. The coil 3 is connected to an appropriate electromotive force measuring circuit 5 and its induced electromotive force is measured.

In use, the detection device is fixedly or semi-fixedly attached to a place or facility where vibration is to be detected by screwing or pasting or other appropriate means. Then, when mechanical vibration (for example, seismic motion) is applied to the detection target place or equipment from the outside, the integrated structure of the detection device including the case 1, the coil 3, and the permanent magnet 4 is vibrated accordingly. In response to this vibration, the steel ball 2 relatively moves within the case 1, and accordingly, the relative position of the steel ball 2 with respect to the coil 3 changes. As a result, the magnetic flux passing through the coil 3 is disturbed, and the magnetic flux changes. Since an induced electromotive force is generated in the coil 3 due to the change in the magnetic flux, lateral and vertical vibrations such as seismic motion can be detected by measuring the electromotive force with an appropriate measuring circuit 5. That is, when the case 1 rolls horizontally, the steel ball 2 inside the case 1 also rolls relatively, and when the case 1 swings vertically, the steel ball 2 inside it also swings relatively, so that one detection The device can detect horizontal and vertical vibrations in multiple directions. The double-headed arrow in FIG. 1 shows how the steel ball 2 moves up and down and left and right in response to vibration, and the dotted line 2 ′ exemplifies the position of the displaced steel ball 2. Since the case 1 has a concave curved surface,
When in the neutral state without vibration, the steel ball 2 naturally settles to a predetermined lowermost position of the case by its own weight and becomes stable. In such a stable state, since the magnetic flux passing through the coil 3 does not change, induced electromotive force does not occur. Therefore, the induced electromotive force corresponding to the vibration is generated only in the coil 3 when the vibration occurs.
Will result from

FIG. 2 exemplifies the state of one waveform of the induced electromotive force generated from the coil 3 in response to vibration. For example, one wobbling produces one waveform as shown in FIG. Usually, the oscillating wave is composed of several waves that repeat with time as the horizontal axis, so such a waveform will be repeatedly measured as long as the vibration continues. FIG. 2A shows an analysis example in which the presence or absence of earthquake motion is detected by determining the voltage level of electromotive force with reference to an appropriate threshold value SH. FIG. 2B shows several electromotive force measurement waveforms having different level heights in an overlapping manner. Considering that the level height of the induced electromotive force generated from the coil 3 corresponds to the acceleration of vibration, this induced electromotive force is used. This shows that the acceleration of vibration can be known by measuring the level of electric power. Although not shown, the wavelength is also an important factor for determining the type of vibration, so whether or not it is a seismic wave by measuring the wavelength or period of the electromotive force waveform It can be determined whether it is a transverse wave. In this way, not only the presence or absence of vibration but also the amount of vibration (acceleration) and frequency characteristics can be measured.

The number of coils 3 is not limited to one, and a plurality of coils may be provided. FIG. 3 shows an example thereof, (a) is a schematic side view, and (b) is a schematic plan view. That is, the four coils 3a, 3b, 3c, 3d along the outside of the lower surface of the case 1
Are arranged two-dimensionally. In this case, each coil 3a,
If the induced electromotive forces of 3b, 3c and 3d are individually measured and the vibration is detected based on the combination thereof, it is possible to collect more detailed information such as the presence or absence of the vibration, the amount and the direction. In the example of the drawing, the steel ball 2 is located at the midpoint between the coils 3a, 3b, 3c, 3d in the neutral state without vibration. When lateral vibration is applied,
A change in magnetic flux occurs in the coils arranged in the swaying direction and electromotive force occurs. Therefore, such an arrangement including a plurality of coils is particularly suitable for detecting the direction of vibration. For example, if a large vibration detection level is obtained for a certain two coils (for example, 3a and 3b), it means that a large lateral vibration is occurring in the straight line direction connecting the two coils (for example, 3a and 3b). . In addition,
Another coil (this will be almost directly under the case 1 like the coil 3 in FIG. 1) is arranged at the central position corresponding to the neutral state, and the vertical vibration is detected by this central coil. You may allow it.

FIG. 4 shows a modification of the multiple coil arrangement of FIG. In FIG. 3B, each coil 3a, 3b, 3c,
Since 3d are arranged at equal intervals, the direction detection sensitivity for roll is substantially uniform. On the other hand, in FIG.
The plurality of coils 3a, 3b, 3c, 3d are arranged at unequal intervals, and the interval between the two specific coils (3a, 3c in the figure) is made narrower than the others. This allows for a narrow spacing of 2
Lateral vibration in the linear direction (Y direction in the figure) connecting the coils (3a, 3c in the figure) is detected by both coils (3a, 3c) even with a small vibration, so the detection sensitivity Means high sensitivity. On the other hand, two coils with wide intervals (3b in the figure,
Lateral vibrations in a straight line direction (X direction in the figure) connecting 3d) are not detected by both coils (3b, 3d) with a small shake, so that the detection sensitivity becomes relatively low. Such unequally spaced coil arrangements having sensitivity in a specific direction are advantageous when applied to vibration detection or acceleration detection in a constant traveling direction in a vehicle such as an automobile.

As a modified example of FIG. 4, as shown in FIG. 5, a plurality of coils 3a, 3b, 3c are provided in a row in a constant roll detection target direction (for example, forward direction), and the constant roll motion is provided. Rolling may be detected with high sensitivity in the detection target direction. Of course, in this case as well, the rolling in the other direction is detected with the same sensitivity as when one coil 3 is provided (that is, because the central coil 3b is provided at least corresponding to the neutral position). It is also possible to detect vertical vibrations.
The response characteristic to vibration can be selected by appropriately selecting the mass of the steel ball 2 housed in the case 1-for example, it does not respond to small vibrations but responds to slow large vibrations. Therefore, it is possible to impart a resonance characteristic to a desired seismic wave. Therefore, it is possible to cancel the noise-like vibration in the light of the purpose of detection (for example, seismic wave detection) and obtain a detection signal that responds better to the desired seismic wave vibration.

FIG. 6 shows that a relatively small amount of magnetic fluid 2a is used in place of the steel ball 2 as the magnetic body housed in the case 1. In FIG. 7, a relatively small amount of magnetic powder 2b is used in place of the steel ball 2 as the magnetic body housed in the case 1. Also in this case, the magnetic fluid 2a or the magnetic powder 2b relatively moves (swings or tilts) according to the vibration of the case 1, and the magnetic flux passing through the coil 3 can be changed. Can generate electricity. FIG. 8 shows an example in which the viscous fluid 7 is contained in the case 1 and the steel balls 2 are arranged in the viscous fluid 7. As a result, it has a cushioning property against vibrations applied from the outside, absorbs small noise-like vibrations due to the surrounding environment, and creates vibrations with a relatively long cycle (long wavelength) or strong acceleration such as seismic waves. It can be configured to respond selectively. It is needless to say that an electromagnet may be used instead of the permanent magnet 4 in each of the above embodiments. Alternatively, an AC magnetic field generator may be used.

FIG. 9 is a schematic vertical sectional view showing another embodiment of the multidirectional vibration detecting device of the present invention. A concave curved case 1 made of a non-magnetic material and a steel ball 2 housed in the case 1.
And the coil 3 installed on the lower surface outside the case 1 are the same as in FIG. 1, but the magnet 4 is not provided. In this example, the output of the coil 3 is connected to the inductance measuring circuit 8 and the inductance (impedance) of the coil 3 is measured. When the steel ball 2 made of a magnetic material is closest to the coil 3, the inductance is maximum, and when the steel ball 2 moves away from the coil 3 in response to vibration, the inductance decreases. Therefore, the vibration can be detected. Also in this case, vibrations in the horizontal and vertical directions can be detected in exactly the same manner as in FIG. Also, FIG.
The variant shown in FIG. 8 can be applied to the embodiment of FIG. 7 in exactly the same way. In each of the above examples,
A spring may be supplementarily attached to the steel ball 2 so as to have a cushioning effect in the vertical or horizontal direction. However, the addition of such a supplementary spring is not the gist of the present invention, but is merely an external addition for implementing the present invention.

FIG. 10 is a schematic external view showing still another embodiment of the multidirectional vibration detecting device of the present invention, showing a state in which the spherical (ball or bowl-shaped) case 1 is viewed from diagonally below. In this example, the plurality of coil portions 30 are arranged over the entire surface of the spherical (ball-shaped or bowl-shaped) case 1 or in an appropriate range. The configuration of each coil unit 30 is
It may take any form of the embodiment described above with reference to FIGS. Therefore, when the configuration of each coil portion 30 conforms to the embodiment of FIGS. 1 to 8, the permanent magnets are provided for each coil portion or in an appropriate arrangement.
In the figure, the illustration is omitted for convenience. In addition, each coil portion 30
In the case where the configuration according to the embodiment of FIG. 1 to FIG. 8 is configured, each may have one coil. As another form, each coil unit 30 may include a primary coil and a secondary coil. It is assumed that the output signals are individually taken out from the respective coil units 30. Of course, the steel ball 2 or other magnetic body is movably housed inside the case 1 as in the embodiment described above with reference to FIGS. 1 to 9.
With this configuration, the steel ball 2 or other magnetic body moves in the case 1 in response to vibration or impact applied to the case 1 from the outside, and a plurality of steel balls 2 or other magnetic bodies are moved depending on the proximity of the steel ball 2 or other magnetic body. An output signal is generated from any one of the coil units 30. Multidirectional vibration or impact can be detected depending on which coil unit 30 produces the output signal. This is suitable for detecting the direction in which an accelerating impact is applied.

FIG. 11 is an enlarged view showing a modified example of the multidirectional vibration detection device of the present invention, which shows a modified example in which the magnet 4 is used as in FIG. In the magnetic field generated by the permanent magnet 4, the magnetic core portion 9 is arranged so that its position can be adjusted via a screw type or other appropriate means.
The tip of the magnetic core 9 is separated by a gap to form the case 1
It is close to the movable magnetic body portion inside, that is, the steel ball 2. The magnetic core portion 9 arranged in the magnetic field of the permanent magnet 4 is magnetized, and magnetic lines of force are emitted from its tip. Therefore, by variably adjusting the protruding position of the magnetic core portion 9, the distance of the gap formed between the tip of the magnetic core portion 9 and the steel ball 2 is variably adjusted, and the magnetic force applied to the steel ball 2 is adjusted to the gap amount. It is adjusted accordingly. As a result, the attractive force exerted on the steel ball 2 by the magnet 4 is variably adjusted, and the movable responsiveness of the steel ball 2 to the mechanical vibration applied from the outside is variably controlled. That is, the steel ball 2 is attracted to the magnet 4 with a force according to the gap amount, so that the free movement of the steel ball 2 is suppressed to some extent, which may cause a slight vibration or noise that is not required to be detected. Even if such a vibration is applied from the outside, the steel ball 2 does not easily move, and it is possible to cancel such a slight vibration or a noise-like vibration so as not to respond to it. Also, the sensitivity of the output of the coil 3 can be adjusted. Here, the boundary vibration condition in which the steel ball 2 starts to move can be variably adjusted by the suction force according to the gap amount. Of course, when the magnetic core portion 9 is formed by a male screw, there is no need to cut a female screw on the magnet itself. Magnetic core part 9
It suffices if there is a space that allows the passage of. When a plurality of coil portions 30 are provided as shown in FIG. 10, the magnetic core portion 9 for adjustment as described above may be provided only in the coil portion 30 immediately below.

[0019]

As described above, according to the present invention, there is an excellent effect that lateral and vertical multidirectional vibrations such as seismic motions can be detected by one detecting device. In addition, since it has a simple structure and can be manufactured at low cost, it can be used as a simple earthquake detector, as a sensor for a safety valve drive mechanism during an earthquake in a propane gas cylinder, as a sensor for various other safety devices, and in vehicles. As a multi-directional vibration (or acceleration or shock) detector,
It can be expected to be easily applied in various application fields, and its application is wide.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional view showing an embodiment of a multidirectional vibration detection device of the present invention.

FIG. 2 is a diagram showing an example of a voltage waveform of an electromotive force obtained in response to vibration by the detection device of FIG.

FIG. 3 is a diagram showing an example in which a plurality of coils are provided as a modified example of the coil arrangement in FIG.

FIG. 4 is a view showing a modified example of the arrangement of a plurality of coils in FIG.

FIG. 5 is a view showing still another modified example of arrangement of a plurality of coils.

FIG. 6 is a diagram showing an example in which a magnetic fluid is used as a modified example of a magnetic body.

FIG. 7 is a diagram showing an example in which magnetic powder is used as a modification of the magnetic body.

FIG. 8 is a diagram showing an example in which steel balls are arranged in a viscous fluid as a modification of the arrangement of steel balls in FIG. 1.

FIG. 9 is a schematic vertical cross-sectional view showing another embodiment of the multidirectional vibration detection device of the present invention.

FIG. 10 is a schematic external view showing yet another embodiment of the multidirectional vibration detection device of the present invention.

11 is a partially enlarged view showing a modified example of FIG.

[Explanation of symbols]

 1 Case 2 Steel ball 2a Magnetic fluid 2b Magnetic powder 3,3a, 3b, 3c, 3d Coil 4 Permanent magnet 5 Electromotive force measurement circuit 7 Viscous fluid 8 Inductance measurement circuit 30 Coil part 9 Magnetic core part

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Nobuyuki Akazu 2-1453-43, Niibori, Higashiyamato-shi, Tokyo (72) Inventor Kazuya Sakamoto 1-1-5 Kawasaki, Hamura-shi, Tokyo, MAC Hamura Court II- 405 (72) Inventor Hiroshi Sakamoto 896-8 Yamada, Kawagoe-shi, Saitama (72) Inventor Akio Yamamoto 1-13-29 Nishi, Kunitachi-shi, Tokyo KM Heights 101

Claims (10)

[Claims] 1. A concave curved surface case made of a non-magnetic material, a magnetic material housed movably in the case according to gravity, a coil installed on the lower surface of the case, and a magnetic field applied to the coil. A magnet, the magnetic body moves in the case in response to vibration in an arbitrary direction applied to the case from the outside, and accordingly, the relative position of the magnetic body with respect to the coil changes, A multidirectional vibration detection device, characterized in that the vibration is detected by measuring an induced electromotive force generated in the coil according to a change. 2. A concave curved surface case made of a non-magnetic material, a magnetic material housed in the case so as to be movable according to gravity, a coil installed on the lower surface of the case, and an inductance of the coil is measured. And a circuit for
The magnetic body moves in the case in response to vibration in an arbitrary direction applied to the case from the outside, and the relative position of the magnetic body with respect to the coil fluctuates accordingly. A multidirectional vibration detection device, characterized in that the vibration is detected by measuring a change in inductance of a coil. 3. The multidirectional vibration detection device according to claim 1, wherein the magnetic body is a rigid spherical body. 4. The multidirectional vibration detection device according to claim 1, wherein the magnetic body is made of a magnetic fluid. 5. The multidirectional vibration detection device according to claim 1, wherein the magnetic body is made of magnetic powder. 6. The multidirectional vibration detection device according to claim 1, wherein the mass of the magnetic material is selected so that a desired seismic wave has resonance characteristics. . 7. The magnetic body is made of a solid, and a viscous fluid is housed in the case, and the magnetic body is arranged in the viscous fluid so as to have a damping characteristic against vibration applied from the outside. 3. The device according to claim 1, wherein the device responds to a vibration having a relatively long period such as a seismic wave.
The multidirectional vibration detection device described in. 8. A plurality of coils are two-dimensionally arranged on a lower surface of the case, an induced electromotive force or an inductance of each coil is individually measured, and multidirectional vibration is detected based on a combination thereof. The multidirectional vibration detection device according to any one of claims 1 to 7, which is characterized. 9. A plurality of the coils are arranged in a line on the lower surface of the case, the induced electromotive force or the inductance of each coil is individually measured, and the roll in one direction is detected based on the combination thereof. The multidirectional vibration detection device according to any one of claims 1 to 7, which is characterized. 10. A concave curved surface case made of a non-magnetic material, a magnetic material housed in the case movably according to gravity, and a plurality of coil portions installed over a predetermined range of the curved surface of the case. The magnetic body moves in the case in response to an impact applied to the case from the outside in an arbitrary direction, and the relative position of the magnetic body with respect to the coil portions fluctuates accordingly. A multi-direction vibration detecting device is characterized in that the direction of impact is detected based on an output generated from any one of the coil portions according to the above.