JP2538535B2 - Inclinometer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inclinometer for measuring an inclination angle of a measuring object.

[0002]

2. Description of the Related Art Conventionally, a heating device such as a gas stove or an oil fan heater is provided with a simple inclinometer consisting of a circular regulation frame and a pendulum such as a chain or rod hanging toward the center of the frame. By observing the tilt angle with the naked eye, it is monitored whether or not the posture of the device is within the proper range. Further, it is possible to place a level in which air bubbles are enclosed together with a liquid on the instrument and roughly measure the inclination of the instrument depending on the position of the air bubbles.

FIG. 12 is a block diagram showing another example of a conventional inclinometer. FIG. 12 (1) shows a state in which the device is not tilted. In this state, the spherical body 3 is fitted in the recess 2 of the base body 1, and the vertically movable piece 4 is mounted on the spherical body 3. Further, a moving contact is provided apart from the lifting piece 4 and is in a non-contact state with the fixed contact 6.

On the other hand, FIG. 12 (2) shows a state in which the instrument is tilted. In this state, the sphere 3 pops out due to gravity, the elevating piece 4 is pushed up, and the moving contact 5 is displaced upward and comes into contact with the fixed contact 6. In this way, by detecting conduction or non-conduction between the moving contact 5 and the fixed contact 6, it is possible to determine whether or not the instrument is tilted.

[0005]

However, it is impossible to quantitatively measure the tilt angle with the conventional simple inclinometer, and the variation of measurement by the observer is extremely large.

Further, the inclinometer using a sphere cannot distinguish from the displacement due to an external impact, and it is difficult to quantitatively measure the inclination angle. Further, if the inclinometer is installed so as to be tilted, the sphere easily pops out of the recess, and the normal operation is not achieved.

An object of the present invention is to provide a compact and lightweight inclinometer capable of measuring the inclination angle of a measuring object with high accuracy.

[0008]

According to another aspect of the present invention, there is provided a tilt sensor including a conductive pendulum supported in a cantilevered manner, and a pair of counter electrodes arranged apart from each other in a displacement direction of the pendulum.
An inclinometer, comprising: a capacitance detection circuit for detecting the capacitance between the pendulum and each counter electrode; and a display means for displaying the output from the capacitance detection circuit in analog.

The present invention further comprises a judgment circuit for comparing the output from the capacitance detection circuit with a predetermined judgment level, and an alarm means for issuing an alarm based on the judgment result of the judgment circuit. Is characterized by.

Further, the present invention is characterized by comprising a low-pass filter for cutting off the output from the capacitance detection circuit in a high frequency range.

Further, the present invention is characterized by comprising a linear conversion circuit for converting the output from the capacitance detection circuit into a signal proportional to the inclination angle.

The present invention is also characterized in that the pendulum is made of conductive single crystal silicon.

[0013]

According to the present invention, when the tilt sensor attached to the object to be measured is tilted at a certain angle, the cantilever-supported pendulum is elastically deformed by gravity, and the distance between the pendulum and one counter electrode is shortened. , The distance between the pendulum and the other counter electrode becomes longer. Therefore, by detecting the capacitance between the pendulum and each counter electrode using a capacitance detection circuit,
By obtaining the change in the distance between the electrodes and displaying the change in analog form, the tilt angle of the measurement object can be measured with high accuracy.

Further, by comparing the output from the capacitance detection circuit with a predetermined judgment level, for example, from 0 degree to 1
It is possible to take measures according to the degree of the inclination angle, such that the range of 0 degrees is normal, the range of 10 degrees to 30 degrees is an alarm operation, and the range of 30 degrees or more is a gas shutoff operation.

Further, by providing a low-pass filter for cutting off the output from the capacitance detection circuit in a high frequency range, it is possible to remove a measurement error due to a shock or the like.

Since a linear conversion circuit for converting the output from the capacitance detection circuit into a signal proportional to the tilt angle is provided, the relationship between the magnitude of the output signal and the tilt angle becomes linear. Direct reading of inclination angle is possible.

Further, since the pendulum is formed of conductive single crystal silicon, it functions as a completely elastic body having no hysteresis, brittleness, creep, etc., so that the measurement accuracy is improved. Further, by using the manufacturing technology related to the silicon wafer, it is possible to mass-produce a sensor of several mm order with high quality.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A shows a tilt sensor 10 according to the present invention.
FIG. 1 (2) is a perspective view showing the tilt sensor 10 in a cutaway manner. The tilt sensor 10 includes a pendulum 15 supported in a cantilever manner, and a pair of electrodes 16 and 17 arranged apart from the pendulum 15 in a direction in which the pendulum 15 is reciprocally displaced (vertical direction in FIG. 1A). Pendulum 15
Is composed of a pendulum body 18 and a cantilever support portion 19, and the cantilever support portion 19 is continuous with the mounting portion 20. The pendulum 15 and the mounting portion 20 are made of conductive single crystal silicon. Further, the mounting portion 20 is separated from the pendulum body 18.
A spacer 21 having the same thickness as is arranged. Electrode 1
Reference numerals 6 and 17 are formed on flat glass plates 22 and 23, and these electrodes 16 and 17 are thin films made of aluminum and are formed by a method such as vapor deposition. Glass plate 2
2, 23 are substrates 24 made of conductive single crystal silicon,
The electrodes 16 and 17 are fixed to 25, respectively, and the electrodes 16 and 17 are electrically connected to the substrates 24 and 25 through the connection holes 26 and 27 formed in the glass plates 22 and 23, respectively. Thus, the sensor S1 is constructed symmetrically with respect to the plane of symmetry 28 of FIG. Since the cantilever support portion 19 is a completely elastic body,
No hysteresis, brittleness or creep. The mounting portion 20, the glass plates 22 and 23, and the substrates 24 and 25 are completely fused through the silicon dioxide, and the spacer 21 is also the same, and thus the internal space 29 is airtight.
It is a vacuum. The distances d1 and d2 between the pendulum body 18 and the electrodes 16 and 17 are about 2 to 5 μm in a state where gravity does not act on the pendulum body 18, and in this embodiment, d1 = d2. The spacer 21 is a pendulum 15
And the same material as the mounting portion 20. In this way, the inclination sensor 10 is formed in a minute shape of, for example, length 2 × width 2 × thickness 3 mm.

The inclination sensor 10 as described above has stable characteristics over a long period of time and can detect the direction of gravity with high accuracy in a wide temperature range of -40 to + 125 ° C. The tilt sensor 10 is symmetrical with respect to the surface 28, and therefore, even if the thermal expansion is performed, the whole is uniformly expanded. Therefore, the combined value of the capacitances of the pendulum body 18 and the electrodes 16 and 17 does not change. The tilt sensor 10 is, for example, 40
Even if an excessive shock of about 00 g (g is gravitational acceleration) is applied, the swing of the pendulum body 18 is caused by the sandwich-shaped electrode 1.
6 and 17, that is, the glass plates 22 and 23, restrict the cantilever support portion 19 supporting the pendulum body 18 from an excessive bending force, and thus the cantilever support portion 1
The damage of 9 can be prevented.

Further, the pendulum 15 and the mounting portion 20
The semiconductor etching technique facilitates fine processing, and the automation of the tilt sensor 10 significantly reduces the number of manufacturing steps, thereby stabilizing the quality and achieving the cost reduction due to the mass production effect. Further, the tilt sensor 10 can be manufactured by the silicon wafer technology, and since the temperature coefficient is very low, the tilt sensor 10 can be adjusted and shipped at room temperature, which can significantly reduce the number of manufacturing steps. In addition, micro etching technology can be adopted, and miniaturization is possible.

2 and 3 show the tilt sensor 10 of FIG.
FIG. 3 is an explanatory diagram showing the operating principle of FIG. FIG. 2A shows a reference state in which the tilt sensor 10 is not tilted, and the pendulum 15 hangs vertically from the mounting portion 20. for that reason,
Even when gravity F acts on the center of gravity G of the pendulum 15, the pendulum 15 is not displaced, and the distances d1 and d2 between the pendulum 15 and the electrodes 16 and 17 do not change. On the other hand, FIG. 2B shows a state where the inclination sensor 10 is inclined at an angle θ with respect to the reference state of FIG. 2A. Gravity F on the center of gravity G of the pendulum 15
Is applied, component force F1 = F.multidot.in the displacement direction of the pendulum 15.
Since sin θ acts and a bending moment is applied to the pendulum 15, the pendulum 15 is elastically deformed. Therefore, the distance d1 becomes smaller, the distance d2 becomes larger, and the pendulum 1
The capacitance between the electrode 5 and the electrodes 15 and 16 changes. Since the component force F2 = F · cos θ acts in the longitudinal direction of the pendulum 15, it does not contribute to the change in the distances d1 and d2.
By detecting the change in the capacitance in this way, the change in the component force F1 can be obtained, and the tilt angle θ can be further measured.

FIG. 3 (a) is a tilt sensor 10 of FIG. 2 (a).
Is a vertically inverted state, and this state can be used as a reference state. In this case, even if gravity F acts on the center of gravity G of the pendulum 15, the pendulum 15 is not displaced, and the distances d1 and d2 between the pendulum 15 and the electrodes 16 and 17 are not changed. On the other hand, in FIG. 3B, the inclination sensor 10 is shown in FIG.
The state which inclines by the angle (theta) with respect to the reference state of (a) is shown. When gravity F acts on the center of gravity G of the pendulum 15, a component force F1 = F · sin θ acts in the displacement direction of the pendulum 15 and a bending moment is applied to the pendulum 15, so that the pendulum 15 elastically deforms. Therefore, this time, the distance d2 decreases and the distance d1 increases, and the electrostatic capacitance between the pendulum 15 and the electrodes 15 and 16 changes. The component force F
Since 2 = F · cos θ acts in the longitudinal direction of the pendulum 15, it does not contribute to changes in the distances d1 and d2. Thus
As in the case of FIG. 2, the change in the component force F1 can be obtained by detecting the change in capacitance, and the tilt angle θ can be measured.

FIG. 4 is a block diagram showing an electric circuit according to an embodiment of the present invention. The pendulum 15 and the electrodes 16 and 17 of the tilt sensor 10 are connected to the capacitance-voltage conversion circuit 41, respectively. Here, the pendulum 15 and each electrode 16, 1
When the electrostatic capacitance between the tilt sensor 10 and C is set to C1 and C2, the tilt sensor 10 of FIG.
In the state of (a) or FIG. 3 (b), the intervals d1, d
Since 2 is the same, the capacitance is C1 = C2.

The capacitance-voltage conversion circuit 41 includes capacitors C1 and C2.
Then, the following equation (1) is calculated to convert into a voltage signal VA and output.

[0025]

[Equation 1]

Here, the combined value (C1-C2) / (C1 + C
2) is the sine of the inclination angle θ of the inclination sensor 10, that is, s
proportional to inθ. V0 is a constant. For example, when tilted from the state of FIG. 2 (a) to the state of FIG. 2 (b),
The distance d1 decreases and the capacitance C1 increases, and conversely, the distance d2 increases and the capacitance C2 decreases. Therefore, in the state of FIG. 2B, the voltage signal VA becomes positive.
On the other hand, when tilted in the direction opposite to that of FIG. 2B, the distance d1 increases and the capacitance C1 decreases, and conversely, the distance d2 decreases and the capacitance C2 increases, so that the voltage signal VA becomes negative.

FIG. 5A is a graph showing conversion characteristics of the capacitance-voltage conversion circuit 41. Capacitance voltage conversion circuit 4 on the vertical axis
When the inclination angle θ is taken on the horizontal axis of the voltage signal VA output by 1, the minimum value MIN at θ = −90 degrees, 0 at θ = 0 degrees, θ =
The curve shows a partial sine wave having a maximum value MAX at 90 degrees. Therefore, the tilt angle θ can be obtained by performing back calculation from the voltage signal VA using the curve of FIG.

Returning to FIG. 4, the voltage signal VA from the capacitance-voltage conversion circuit 41 is input to the low-pass filter 42 for cutting off the high frequency band. The low-pass filter 42 removes the influence of disturbance such as impact on the tilt sensor 10 by cutting the frequency component higher than a predetermined cutoff frequency to improve the measurement accuracy.

The output of the low pass filter 42 is input to the linear conversion circuit 43. The linear conversion circuit 43 has a function of converting into a voltage signal VB that is proportional to the tilt angle θ. That is, as shown in FIG. 5B, when the tilt angle θ changes from −90 degrees to 90 degrees, the voltage signal VB that changes linearly is output. Therefore, if the magnitude of the voltage signal VB is displayed, the inclination angle θ can be directly read as it is.

The voltage signal V output by the linear conversion circuit 43
B is input to a drive circuit 44 for driving an LED bar display 45 in which a plurality of LEDs (light emitting diodes) are arranged in a line, and L is proportional to the magnitude of the voltage signal VB.
The number of illuminated ED bar displays 45 changes, and the tilt angle θ is displayed in analog form to the user.

Further, the voltage signal VB output from the linear conversion circuit 43 is also input to the determination circuit 46, compared with a preset determination level, and based on the determination result, the display lamp 47, the alarm buzzer 48 and the gas shutoff. The valve 49 is selectively operated. For example, as shown in FIG.
If the judgment levels are set to ± θ1 and ± θ2 respectively,
1) If the tilt angle θ is in the range of −θ1 to + θ1, it is determined that the tilt angle of the measurement target is within the proper range. 2) Tilt angle θ is in the range of −θ2 to −θ1 or + θ1 to + θ2
If it is within the range, the object to be measured is inclined and becomes in a dangerous state, and the display lamp 47 is turned on or the alarm buzzer 48 is operated to notify the user. 3) If the inclination angle θ is in the range of −90 degrees to −θ2 or the range of + θ2 to +90 degrees, the operation of the measurement object is forcibly stopped. For example, if the measurement object is a gas appliance, the gas cutoff valve 49 is operated to cut off the gas supply. In this way, stepwise safety measures can be taken according to the degree of inclination.

FIG. 6 is a perspective view showing an example in which the inclinometer of the present invention is mounted on the gas instrument 80. Many gas appliances 80 such as a gas stove and a gas fan heater have a rectangular parallelepiped housing and have a structure in which warm air is discharged from the front. The inclination sensor 10 of FIG. 1 is attached to the side surface of the gas appliance 80, and the tilt angle of the gas appliance 80 is measured with high accuracy by aligning the front-back direction in which the gas appliance 80 easily swings with the displacement direction of the pendulum 15. it can. Further, when the predetermined inclination angle is exceeded, the gas supply is forcibly cut off, and safety measures such as a fall due to an earthquake are taken.

FIG. 7 shows the inclinometer of the present invention as a crane truck 81.
It is the schematic which shows the example mounted in. When a mobile crane lifts loads, if the load moment exceeds the reverse moment due to the weight of the vehicle body, it may fall. Therefore, by mounting the tilt sensor 10 shown in FIG. 1 so that the swing direction of the boom 82 and the displacement direction of the pendulum 15 coincide with each other, the danger angle of the boom 82 is detected, and an alarm or a warning is issued before a fall accident occurs. Output a stop signal.

FIG. 8 is a schematic view showing an example in which the inclinometer of the present invention is mounted on the pipe inspection robot 83. The in-pipe inspection robot 83 travels in the pipe 84 and monitors the inner surface state with an image sensor. In this case, by mounting the inclination sensor 10 of FIG. 1 on the in-pipe inspection robot 83 and measuring the inclination angle around the two horizontal axes, the posture control of the in-pipe inspection robot 83 becomes possible.

FIG. 9 shows the inclinometer of the present invention as a satellite antenna 8.
FIG. 6 is a schematic view showing an example mounted on No. 6; When the wireless relay station 85 such as a vehicle or a ship automatically tracks a broadcasting satellite while moving, it is necessary to correctly orient the satellite antenna 86 such as a parabolic antenna to the broadcasting satellite. Therefore, by mounting the inclination sensor 10 of FIG. 1 on the satellite antenna 86, elevation angle control becomes possible.

FIG. 10 is a schematic view showing an example in which the inclinometer of the present invention is mounted on the pipeline 87. Maintenance and inspection of the pipeline 87 such as oil and gas complex requires a great deal of labor and cost. Therefore, the tilt sensor 10 is attached to the pipeline 87 and the base 88, and parallelism, posture, distortion, etc. are set for 24 hours. Therefore, it is possible to monitor and to prevent a disaster from occurring.

FIG. 11 is a schematic view showing an example in which the inclinometer of the present invention is mounted on a building 89. The ground of the building 89 changes with the lapse of time, and an inclination, a twist, or the like occurs. Therefore, by mounting the tilt sensor 10 on the building 89, the tilt angle of the building 89 can be accurately measured, and the occurrence of collapse and the time of rebuilding can be monitored.

[0038]

As described in detail above, according to the present invention, the inclination angle of the object to be measured can be accurately measured and appropriately displayed in analog form. Further, by comparing the output from the capacitance detection circuit with the predetermined determination level, it becomes possible to take measures depending on the degree of the tilt angle. In addition, by providing a low-pass filter, it is possible to eliminate measurement error due to impact or the like. Further, by providing a linear conversion circuit for converting the output from the capacitance detection circuit into a signal proportional to the tilt angle, the relationship between the magnitude of the output signal and the tilt angle becomes linear, so that the tilt angle Direct reading is possible. Further, since the pendulum is made of conductive single crystal silicon, a small and highly accurate tilt sensor can be obtained.

[Brief description of drawings]

FIG. 1 (1) is a sectional view of a tilt sensor 10 according to the present invention, and FIG. 1 (2) is a perspective view showing the tilt sensor 10 in a cutaway manner.

FIG. 2 is an explanatory diagram showing the operating principle of the tilt sensor 10 of FIG.

FIG. 3 is an explanatory diagram showing an operation principle of the tilt sensor 10 of FIG.

FIG. 4 is a block diagram showing an electric circuit according to an embodiment of the present invention.

5A is a graph showing conversion characteristics of the capacitance-voltage conversion circuit 41, and FIG. 5B is a linear conversion circuit 43.
It is a graph which shows the conversion characteristic of.

FIG. 6 is a perspective view showing an example of mounting the inclinometer of the present invention on a gas instrument 80.

FIG. 7 is a schematic view showing an example in which the inclinometer of the present invention is mounted on a crane truck 81.

FIG. 8 is a schematic view showing an example in which the inclinometer of the present invention is mounted on a pipe inspection robot 83.

FIG. 9 is a schematic view showing an example in which the inclinometer of the present invention is mounted on a satellite antenna 86.

FIG. 10 is a schematic view showing an example in which the inclinometer of the present invention is mounted on a pipeline 87.

FIG. 11 is a schematic view showing an example in which the inclinometer of the present invention is mounted on a building 89.

FIG. 12 is a configuration diagram showing another example of a conventional inclinometer.

[Explanation of symbols]

 10 Inclination sensor 15 Pendulum 16, 17 Electrode 19 Cantilever support part 41 Capacitance voltage conversion circuit 42 Low pass filter 43 Linear conversion circuit 45 LED bar display 47 Indicator lamp 48 Alarm buzzer 49 Gas cutoff valve

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shozo Fujisawa 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka, Osaka Gas Co., Ltd. (56) Reference JP-A-2-49106 (JP, A)

Claims (5)

(57) [Claims] 1. A tilt sensor comprising a conductive pendulum supported in a cantilever manner, and a pair of counter electrodes arranged apart from each other in the displacement direction of the pendulum, and a capacitance between the pendulum and each counter electrode. An inclinometer, comprising: a capacitance detection circuit for detecting; and display means for displaying an output from the capacitance detection circuit in analog. 2. A determination circuit for comparing an output from the capacitance detection circuit with a predetermined determination level, and an alarm means for issuing an alarm based on the determination result of the determination circuit. The inclinometer according to claim 1. 3. The inclinometer according to claim 1, further comprising a low-pass filter for cutting off an output from the capacitance detection circuit in a high frequency range. 4. The inclinometer according to claim 1, further comprising a linear conversion circuit for converting an output from the capacitance detection circuit into a signal proportional to an inclination angle. 5. The inclinometer according to claim 1, wherein the pendulum is made of conductive single crystal silicon.