JP2000055655A - Double-axis type inclination sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly detect an inclination angle to each turning direction making orthogonal double-axis each other as centers in spite of a simple structure that a liquid dielectric body is sealed in an accommodating container. SOLUTION: A air-tight chamber for accommodating a fluid in which a bottom surface and a ceiling surface are parallel each other is formed in a rectangular and flat accommodating container 2 mounted to an agricultural machinery in a horizontal state. A first and second plane-like electrodes 3a, 3b disposed at a plane symmetric state making an X axis being a lateral axis in the agricultural machinery as a symmetric axis and a third and fourth plane-like electrodes 3c, 3d disposed at a plane symmetric state making a Y axis being a forward/backward axis in the agricultural machinery as a symmetric axis are formed on the bottom surface of the air-tight chamber 2b for accommodating a fluid at an electrically insulated state. A common plane-like electrode 4 is formed on the ceiling surface in a state opposed to the first to fourth plane-like electrodes 3a to 3d. An inclination angle-detecting action is carried out based on a variation of an electrostatic capacity between the plane-like electrodes 3a to 3d and the common plane-like electrode 4. A silicon oil is sealed in the air-tight chamber 2b for accommodating a fluid in a state that a space portion is remained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitance type inclination sensor in which a liquid dielectric is sealed between opposed electrodes, and more particularly to a capacitance type inclination sensor centered on a first axis and a second axis orthogonal to each other. The present invention relates to a biaxial inclination sensor capable of detecting an inclination angle in each rotation direction.

[0002]

Heretofore, a liquid dielectric such as silicone oil has been sealed between opposed electrodes provided in a case, and the above-mentioned opposed electrode generated by the movement of the silicone oil in accordance with the inclination of the case. There is provided an inclination sensor that detects the inclination angle of the case based on a change in capacitance between the sensors. Such a tilt sensor,
Since it has advantages such as simple structure and sufficient durability and relatively high accuracy, it has been widely used. However, since the tilt sensor described above can detect only a rotation angle in a certain direction, for example, in an agricultural machine such as a tractor, each rotation about two axes orthogonal to each other such as a pitch and a roll. In the case of using the sensor for detecting an angle, it is necessary to provide two sets of the tilt sensors, which raises a problem that a cost increase cannot be avoided.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a simple structure in which a liquid dielectric is sealed in a storage container, but each rotation direction about two axes orthogonal to each other. An object of the present invention is to provide a two-axis tilt sensor that can reliably detect a tilt angle to a tilt angle.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a biaxial tilt for detecting tilt angles in respective rotation directions about a first axis and a second axis orthogonal to each other. In the sensor, a flat storage container in which a fluid storage airtight chamber in which the bottom surface and the ceiling surface are parallel to each other is formed, which is mounted horizontally with respect to the mounting position,
A first to a fourth formed on one side of a bottom surface and a ceiling surface of the fluid storage airtight chamber in a state of being electrically insulated from each other;
A planar electrode, a common planar electrode formed on the other side of the bottom surface and the ceiling surface of the fluid storage airtight chamber so as to face the first to fourth planar electrodes, and the fluid storage airtight chamber. A liquid dielectric sealed in a state where a space is left in the room, and the first and second planar electrodes are arranged symmetrically with respect to the first axis; 3rd and 4th
Are arranged symmetrically with respect to the second axis,
The tilt angle detecting operation is performed based on a change in capacitance between each of the first to fourth planar electrodes and the common planar electrode (claim 1).

According to such a configuration, when the storage container mounted in a horizontal state with respect to the mounting position holds the horizontal state, the liquid dielectric sealed in the fluid storage airtight chamber inside the storage container is held. The body has a uniformly distributed state. From this state, when the storage container is tilted in the direction of rotation about the first axis, the liquid dielectric is applied to the first and second planar electrodes arranged symmetrically with respect to the first axis. It will flow to one side. For this reason, the capacitance between one side of the first and second planar electrodes and the common planar electrode increases in accordance with the inflow of the liquid dielectric, and the first and second planar electrodes are increased. The capacitance between the other side and the common planar electrode decreases in response to the outflow of the liquid dielectric. In this case, since the amount of increase or decrease in the capacitance changes depending on the inclination angle of the storage container, the inclination angle of the storage container can be detected based on the amount of increase or decrease.

When the storage container is tilted in the direction of rotation about the second axis orthogonal to the first axis, the liquid dielectric is placed in a symmetric state with respect to the second axis. And flow to one side of the fourth planar electrode. Therefore, the capacitance between one side of the third and fourth planar electrodes and the common planar electrode increases in accordance with the inflow of the liquid dielectric, and the third and fourth planar electrodes are increased. The capacitance between the other side and the common planar electrode decreases in response to the outflow of the liquid dielectric. Since the amount of increase or decrease of the capacitance in this case changes depending on the inclination angle of the storage container,
The inclination angle of the storage container can be detected based on the increase / decrease amount.

Therefore, while having a simple structure in which the liquid dielectric in one storage container is merely sealed, the inclination angles in the respective rotation directions about the first axis and the second axis which are orthogonal to each other can be ensured. It will be detectable.

In this case, the first and second planar electrodes are formed in the same shape and arranged in a plane-symmetrical state with the first axis as a symmetric axis, and the third and fourth planar electrodes are arranged in a plane. It may be configured to be formed in the same shape and arranged in a plane symmetric state with the second axis as a symmetric axis (claim 2). According to such a configuration, when the storage container holds a horizontal state, that is, when the liquid dielectric sealed in the fluid storage airtight chamber therein is in a state of being uniformly distributed, The capacitance between each of the first and second planar electrodes and the common planar electrode becomes equal, and the capacitance between each of the third and fourth planar electrodes and the common planar electrode becomes smaller. Since they are equal, output signal processing according to the change in the capacitance can be easily performed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a main structure in a disassembled state, and FIGS. 2 (a) and 2 (b) show the entire longitudinal sectional structure and transverse sectional structure. In FIGS. 1 and 2, the biaxial tilt sensor 1 has a tilt angle in each rotation direction about a first axis and a second axis orthogonal to each other,
For example, a pitch angle centered on a horizontal axis (first axis: hereinafter referred to as an X axis) and a longitudinal axis (second axis: hereinafter referred to as a Y axis) of an agricultural machine such as a tractor.
, And has a rectangular flat container 2 mounted horizontally at a predetermined position of the agricultural machine.

The storage container 2 has, for example, a container-shaped main body 2a having an open upper surface and an air-tight chamber 2b for fluid storage therein by closing the upper opening of the main body 2a in an airtight manner (see FIG. 2).
The fluid-tight chamber 2b has a bottom surface (the inner bottom surface of the container-like main body 2a) and a ceiling surface (the back surface of the lid portion 2c) in parallel with each other. ing. In addition, such a storage container is mounted such that sides orthogonal to each other are parallel to the X axis and the Y axis, respectively.

On the rectangular inner bottom surface of the main body 2a, first, second, third, and fourth planar electrodes 3a, 3b, 3c, and 3d having the same shape and electrically insulated from each other are provided. The inner bottom surface is provided in a form divided into four along the diagonal line. That is, each of the planar electrodes 3a to 3d is formed in a triangular shape, and the first and second planar electrodes 3a and 3d are formed.
b is arranged in a plane symmetric state with the X axis as a symmetry axis,
The third and fourth planar electrodes 3c and 3d are arranged in plane symmetry with the Y axis as the axis of symmetry.

The back surface of the lid 2c is provided with the first to fourth
A rectangular common planar electrode 4 is formed facing the planar electrodes 3a to 3d. The fluid-containing airtight chamber 2b is filled with, for example, a silicone oil 5 (see FIG. 2) as a liquid dielectric while leaving a space.

Thus, the first to fourth planar electrodes 3
A total of four capacitors are formed between each of the electrodes a to 3d and the common planar electrode 4. The capacitance of the capacitors depends on the amount of the silicone oil 5 located between the electrodes. It will change greatly. In this case, the biaxial tilt sensor 1 includes first to fourth planar electrodes 3a to 3a.
d, a total of four individual terminals connected to each other and a common terminal connected to the common planar electrode are provided.
The equivalent circuit of such a two-axis tilt sensor 1 is in the state shown in FIG. In FIG. 4, C1 to C4 are capacitors formed between the first to fourth planar electrodes 3a to 3d and the common planar electrode 4, respectively, T1 to T4 are the individual terminals, and T0 is the above-mentioned individual terminal. Common terminal.

The biaxial tilt sensor 1 constructed as described above.
In this case, when the storage container 2 mounted horizontally at a predetermined position of the agricultural machine holds the horizontal state, the silicone oil 5 sealed in the fluid storage airtight chamber 2b therein is uniformly distributed. It has a distributed state. In this case, since the first to fourth planar electrodes 3a to 3d are formed in the same shape, the capacitances of the capacitors C1 to C4 are equal to each other.

If pitching occurs in the agricultural machine from such a state, the storage container 2 is inclined in the direction of rotation about the X axis, and as shown in FIG. 5 flows to one side (the first planar electrode 3a side in the example of FIG. 3) of the first and second planar electrodes 3a and 3b arranged symmetrically with respect to the X axis. Become. Therefore, in the example of FIG.
a and a capacitor C1 formed between the common planar electrode 4
The capacitance of the capacitor C2 formed between the second planar electrode 3b and the common planar electrode 4 increases due to the inflow of the silicone oil 5. It will decrease accordingly. When the storage container 2 is tilted in the direction opposite to the above, the capacitance of the capacitor C1 formed between the first planar electrode 3a and the common planar electrode 4 causes the outflow of the silicone oil 5. And the capacitance of the capacitor C2 formed between the second planar electrode 3b and the common planar electrode 4 increases according to the inflow of the silicone oil 5.
Since the amount of increase or decrease in the capacitance in each case changes depending on the inclination angle of the storage container 2 around the X axis, the amount of increase or decrease in the capacitance of the capacitors C1 and C2 is determined. The inclination angle of the storage container 2 around the X axis, that is, the pitch angle of the agricultural machine can be detected.

Further, when rolling occurs in the agricultural machine, the storage container 2 is inclined in the direction of rotation about the Y axis, so that the silicone oil 5 is symmetrical with respect to the Y axis. And fourth planar electrodes 3 arranged at
It flows to one side of c and 3d. For this reason,
A capacitor C3 or C4 formed between one side of the third and fourth planar electrodes 3c and 3d and the common planar electrode 4.
Of the third and fourth planar electrodes 3c and 3d and the capacitor C4 or C3 formed between the other side of the third and fourth planar electrodes 3c and 3d and the common planar electrode 4. Is reduced in accordance with the outflow of the silicone oil 5. Since the amount of increase or decrease in the capacitance in this case changes depending on the inclination angle of the storage container 2 around the Y axis, these capacitors C3 and C4
The inclination angle of the storage container 2 around the Y axis, that is, the roll angle of the agricultural machine can be detected based on the increase or decrease of the capacitance of the storage container 2.

Accordingly, while having a simple structure in which the silicone oil 5 is sealed in one storage container 2, the inclination angles in the respective rotation directions about the X-axis and the Y-axis, which are orthogonal to each other, (for the agricultural machine) Pitch angle and roll angle) can be reliably detected. In this case, for example, the change in the capacitance of the pair of capacitors C1 and C2 and the change in the capacitance of the pair of capacitors C3 and C4 are
Since it is generated differentially according to the inclination of the storage container 2, it is possible to obtain a large detection output, which can contribute to improvement in resolution and the like. In addition, the first to fourth planar electrodes 3c to 3d are formed in the same shape, and each two are arranged in a plane symmetric state with the X axis and the Y axis as symmetric axes. When 2 is in a horizontal state, that is, when the silicone oil 5 is uniformly distributed, the capacitance of each of the capacitors C1 to C4 becomes equal, and the output signal processing according to the change in the capacitance is performed. Another advantage is that it can be easily performed.

FIGS. 4 and 5 show an example of a circuit configuration for performing the above-described output signal processing, which will be described below. The common terminal T0 and the individual terminals T1 to T4 of the biaxial tilt sensor 1 are connected to the input terminals Q0 to Q4 of the circuit unit 6, respectively. In the circuit unit 6, analog switches 7 to 10, a signal processing circuit 11 for a pitch angle, and a signal processing circuit 12 for a roll angle are provided. The analog switches 7 to 10 are configured to be switched between a state in which the contacts (ca) are turned on and a state in which the contacts (c-b) are turned on, and are connected as follows.

The analog switch 7 having the common contact c connected to the input terminal Q1 has the contact a connected to the power supply terminal + Vcc, and the contact b connected to the input terminal A of the pitch angle signal processing circuit 11.
It is connected to the. In the analog switch 8 having the common contact c connected to the input terminal Q2, the contact a is connected to the ground terminal, and the contact b is connected to the input terminal A of the pitch angle signal processing circuit 11. Common contact c is input terminal Q3
Is connected to the power supply terminal + Vcc, and the contact b is connected to the roll angle signal processing circuit 1.
2 input terminal A. In the analog switch 10 having the common contact c connected to the input terminal Q4, the contact a is connected to the ground terminal, and the contact b is connected to the input terminal A of the signal processing circuit 12 for the roll angle.

Although not specifically shown, the circuit unit 6 includes an oscillation circuit that generates a clock pulse of, for example, about 30 kHz, and a delay that generates a switching timing of each of the analog switches 7 to 10 based on the clock pulse. A circuit is provided. In the circuit unit 6, the input terminal Q0 is connected to the signal processing circuit 1 for pitch angle.
1 input terminal B and the input terminal B of the roll angle signal processing circuit 12.

As a result of the above connection, when the respective contacts (ca) of the analog switches 7 and 8 are turned on,
A power supply voltage is applied to the series circuit of the capacitors C1 and C2 and they are charged, and a voltage signal V1 having a level corresponding to the capacitance of the capacitors C1 and C2 is obtained from the common terminal T0. . When the contacts (ca) of the analog switches 9 and 10 are turned on, the power supply voltage is applied to the series circuit of the capacitors C3 and C4, and they are charged.
From 0, a voltage signal V2 of a level corresponding to the capacitance of the capacitors C3 and C4 can be obtained.

The pitch angle signal processing circuit 11 receives the voltage signal V1 as an object of signal processing at an input terminal B, and the roll angle signal processing circuit 12 receives the voltage signal V2 as an object of signal processing at an input terminal B. is there. In this case, since the pitch angle signal processing circuit 11 and the roll angle signal processing circuit 12 have basically the same configuration, only the internal configuration of the pitch angle signal processing circuit 11 will be described below with reference to FIG. Description will be made with reference to the drawings, and description of the internal configuration of the roll angle signal processing circuit 12 will be omitted.

That is, the input terminal B of the pitch angle signal processing circuit 11 is connected to the input terminal of the integration circuit 13 having the capacitor 13a as an integration element.
An analog switch 14 for selectively enabling the integration operation is connected in parallel to a. This integration circuit 1
3 is supplied to a sample-and-hold capacitor 16 via an analog switch 15, and the sampling voltage of the capacitor 16 is output via a voltage follower 17, an inverting amplifier circuit 18 and a filter circuit 19. The signal is output from the terminal P.

The analog switches 14 and 15
Are operated by the same oscillation circuit and delay circuit as the analog switches 7 to 10. Also,
An input terminal A of the pitch angle signal processing circuit 11 is connected to a bias voltage V for the integrator 13 and the inverting amplifier 18.
BIAS is connected to a reference potential line 20 to be applied. Further, the inverting amplifier circuit 18 has a gain adjustment circuit 2
1 and a midpoint adjustment circuit 22 are provided in association therewith.

In such a circuit configuration, the following output signal processing is repeatedly performed at a relatively short cycle. First, the pitch angle signal processing circuit 11 is operated as follows. That is, the analog switch 14 is turned off to make the integrating circuit 13 operable to perform the integration operation. Thereafter, the contacts (ca) of the analog switches 7 and 8 are turned on to charge the series circuit of the capacitors C1 and C2. Then, a voltage signal V1 is generated according to the charging, and the voltage signal V1 is integrated by the integration circuit 13. Thereafter, at the timing when charging of the capacitors C1 and C2 is completed, the analog switch 15 is turned on, and the integrated output is sampled and held by the capacitor 16.
This sampling voltage is amplified by an inverting amplifier circuit 18 after passing through a voltage follower 17 and output. The gain and the midpoint are adjusted in advance by the gain adjustment circuit 21 and the midpoint adjustment circuit 22. Then, after the analog switch 15 is turned off, the contacts (c-b) of the analog switches 7 and 8 are turned on to set the capacitor C1.
And the charge of C2 is rapidly discharged, and at the same time, the analog switch 14 is turned on to rapidly discharge the received charge of the capacitor 13a. The charge of the capacitor 16 is spontaneously discharged.

When a series of signal processing operations in the pitch angle signal processing circuit 11 is completed, the signal processing operation in the roll angle signal processing circuit 12 is similarly executed. By performing the processing operation alternately by the pitch angle signal processing circuit 11 and the roll angle signal processing circuit 12, the detection operation of the pitch angle and the roll angle is performed continuously.

The present invention is not limited to the above-described embodiment, but can be expanded or modified as described below. Although one common planar electrode 4 is provided, it can be divided into, for example, shapes corresponding to the first to fourth planar electrodes 3a to 3d. The first to fourth planar electrodes 3a to 3d are provided on the bottom side of the airtight chamber 2b for storing fluid.
Are formed, and the common planar electrode 4 is formed on the ceiling surface side. However, the arrangement relationship between them can be reversed. The liquid dielectric is not limited to the silicone oil 5, and other fluids can be used. Storage container 2
Is formed in a rectangular shape, but may be formed in various shapes such as a flat short cylindrical shape.

[0028]

As is apparent from the above description, according to the first aspect of the present invention, the first to the first to the electrically insulated state are provided on one side of the bottom surface and the ceiling surface of the airtight chamber for storing fluid. A fourth planar electrode is formed, and a common planar electrode facing the first to fourth planar electrodes is formed on the other side of the bottom surface and the ceiling surface. After enclosing the liquid dielectric while leaving a space, the first and second planar electrodes are arranged symmetrically with respect to the first axis, and the third and fourth planar electrodes are arranged. Since the planar electrodes are arranged symmetrically with respect to the second axis, each of the electrodes has a simple structure in which a liquid dielectric is sealed in a storage container, but each time around two axes orthogonal to each other. This has the beneficial effect that the tilt angle in the moving direction can be reliably detected. Door can be.

According to the second aspect of the present invention, the first and second planar electrodes are formed in the same shape and the first and second planar electrodes are formed in the same shape.
Since the third and fourth planar electrodes are formed in the same shape and arranged in a plane-symmetric state with the second axis as the symmetry axis, When the storage container holds the horizontal state, the capacitance between each of the first and second planar electrodes and the common planar electrode can be equalized, and the third and fourth planar electrodes can be connected to each other. The capacitance between each of the common planar electrodes can be made equal to each other, and there is an advantageous effect that output signal processing according to a change in the capacitance can be easily performed.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing one embodiment of the present invention.

FIG. 2 is a diagram showing the entire longitudinal sectional structure and transverse sectional structure.

FIG. 3 is a diagram corresponding to FIG. 2 for explaining operation.

FIG. 4 is an equivalent circuit diagram of a two-axis tilt sensor.

FIG. 5 is a diagram showing an electrical configuration of an output signal processing circuit together with an equivalent circuit of a two-axis tilt sensor.

FIG. 6 is a circuit configuration diagram showing an electrical configuration of a main part.

[Explanation of symbols]

1 is a biaxial tilt sensor, 2 is a storage container, 2b is an airtight chamber for storing fluid, 3a to 3d are first to fourth planar electrodes,
Denotes a common planar electrode, 5 denotes silicone oil (liquid dielectric), 6 denotes a circuit unit, 7 to 10 denote analog switches, 11 denotes a pitch angle signal processing circuit, and 12 denotes a roll angle signal processing circuit.

Claims (2)

[Claims] 1. A biaxial tilt sensor for detecting a tilt angle in each rotation direction about a first axis and a second axis orthogonal to each other, wherein the two-axis tilt sensor is mounted horizontally in a mounting position, and A flat storage container formed with a fluid storage airtight chamber having a bottom surface and a ceiling surface parallel to each other; and a state in which one of the bottom surface and the ceiling surface of the fluid storage airtight chamber is electrically insulated from each other. First to fourth formed by
A common planar electrode formed on the other side of the bottom surface and the ceiling surface of the airtight chamber for fluid storage in a state facing the first to fourth planar electrodes; A liquid dielectric sealed with a space left in the room, wherein the first and second planar electrodes are arranged symmetrically with respect to the first axis, and the third and the second planar electrodes are arranged symmetrically with respect to the first axis. The four planar electrodes are arranged symmetrically with respect to the second axis, and the inclination angle is detected based on a change in capacitance between the first to fourth planar electrodes and the common planar electrode. A two-axis tilt sensor that performs an operation. 2. The first and second planar electrodes are formed in the same shape and are arranged in a plane-symmetrical state with the first axis as a symmetric axis, and the third and fourth planar electrodes are identical. 2. The biaxial tilt sensor according to claim 1, wherein the biaxial tilt sensor is formed in a shape and arranged in a plane-symmetric state with the second axis as a symmetric axis.