JPH0446170Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is an electrostatic capacitor that can be mounted on, for example, construction machinery or agricultural machinery to detect the inclination of the construction machinery, etc., and used to warn of the machinery falling over. The present invention relates to a capacitive tilt sensor.

[Conventional technology]

The applicant has previously developed a capacitive tilt sensor that is installed on construction machinery and used to sound a buzzer or the like when the tilt of the construction machine exceeds a certain value to warn of the construction machine falling over. As shown in FIG. 8, FIG. 9, and FIG. 10, we proposed the following. That is, in FIG. 8, FIG. 9, and FIG. 10, 1 is a closed container with a circular bottom surface, 2 is a lid of the closed container 1, which is composed of a printed wiring board, and has cylindrical electrodes 3 and 4, which will be described later. It serves as a connecting member with an external signal processing circuit.

3 is a cylindrical electrode having an inner diameter R ₁ , and 4 is a cylindrical electrode provided concentrically with the cylindrical electrode 3 and having an inner diameter R ₂ (R ₂ <R ₁ ). These cylindrical electrodes 3 and 4 are fixed to the lid 2 of the closed container 1 so that the center of their concentric circles is the center of the closed container 1.

Reference numeral 5 denotes a dielectric liquid such as silicone oil. In this example, the dielectric liquid 5 is sealed up to a level Q where the lower ends of the cylindrical electrodes 3 and 4 are located, with the closed container 1 kept horizontally. It is injected into the container 1. Therefore, when the closed container 1 is kept horizontal, the lower ends of the cylindrical electrodes 3 and 4 are in contact with the level of the dielectric liquid 5. In addition, as shown in FIG. 9, the cylindrical electrodes 3 and 4
It has terminals 3t and 4t at the ends fixed to the lid 2, and the terminals 3t and 4t are used to connect to the lid 2, that is, the conductive wire pattern formed on the printed wiring board.

FIG. 10 is an explanatory diagram of the operation of the example shown in FIG. 8, and FIG. 10A shows the case where the closed container 1 is tilted clockwise by -θ from a horizontal state, and FIG. , is a diagram showing a case where the closed container 1 is tilted counterclockwise by +θ from a state kept horizontally. As shown in FIG. 10, the airtight container 1
However, even when tilted clockwise or counterclockwise, if the absolute value of the tilt angle θ is the same, then both electrodes 3,
Since the shape of the electrode 4 is cylindrical, the amount of the dielectric liquid 5 that enters between the electrodes 3 and 4 is the same no matter which direction the closed container 1 is tilted.
The capacitance values between 4 are also the same. Due to the difference in dielectric constant between the space and the dielectric liquid 5, the capacitance value between the electrodes 3 and 4 increases as the absolute value of the inclination angle increases.

[The problem that the idea aims to solve]

However _, in a capacitive tilt sensor as shown in FIG. 3 and 4
There is a phenomenon in which bridging 5a of the dielectric liquid 5 between the electrodes 3 and 4 occurs, and as this inclination angle increases further, the bridging 5a of the dielectric liquid 5 between the electrodes 3 and 4 disappears. The change in capacitance between No. 3 and No. 4 was discontinuous, and the variation in capacitance change with respect to the slope became large, making it impossible to measure the slope properly.

In view of this, the present invention aims to provide a capacitive tilt sensor that can perform good tilt measurements.

[Means for Solving the Problems] The capacitive tilt sensor according to item 1 of the present invention includes a pair of concentric cylindrical members 6a, as shown in FIGS. 1 and 2 and FIGS. 4 and 5, for example. , 6b, and the upper part (Fig. 1, Fig. 2) or lower part (Fig. 4, Fig. 5) of the cylindrical members 6a, 6b.
It has a pair of cylindrical electrodes 3, 4 formed in The lever is designed to detect the inclination of the closed container 6.

Further, the capacitive tilt sensor according to the second aspect of the present invention includes a closed container 6 consisting of a pair of concentric cylindrical members 6b and 6c, and one of the cylindrical members 6b and 6c, as shown in FIGS. 6 and 7, for example. The first and second differential cylindrical electrodes 4a and 4b formed on the other 6c of the cylindrical members 6b and 6c are formed opposite to both the first and second differential cylindrical electrodes 4a and 4b. It has a common cylindrical electrode 3a and a dielectric liquid 5 partially sealed in this airtight container 6, and the first and second differential cylindrical electrodes 4a and 4b and this common cylindrical electrode 3a generate static electricity. The inclination of the closed container 6 is detected by differentially detecting the capacitance change.

[Effect]

According to the first aspect of the present invention, a pair of cylindrical members 6
The liquid level of the dielectric liquid 5 in the ring-shaped sealed container 6 formed from the sealed container 6 changes continuously according to the inclination of the sealed container 6, and the capacitance changes with respect to the inclination of the sealed container 6. The variation is small and the slope can be detected satisfactorily.

According to the second aspect of the present invention, in the first aspect of the present invention, the cylindrical electrode is connected to the first and second differential electrodes 4a and 4.
b and a common electrode 3a, it has the same effect as the above-mentioned item 1 of the present invention, and can obtain a detection output twice as large as the inclination of the closed container 6, resulting in a better inclination angle. Detection can be performed.

〔Example〕

Hereinafter, one embodiment of the capacitive tilt sensor of the present invention will be described with reference to FIGS. 1 to 3.
In FIGS. 1 and 2, parts corresponding to those in FIGS. 8 and 10 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In FIGS. 1 and 2, 6a indicates a cylindrical container made of an insulator having a circular bottom surface, and this cylindrical container 6a
An insulating cylindrical member 6b having an outer diameter smaller than the inner diameter of the cylindrical container 6a is provided concentrically therein, and a ring-shaped closed container 6 is formed by the outer wall of the cylindrical member 6b and the inner wall of the cylindrical container 6a.

In the example shown in FIG. 1, the cylindrical electrode 3 is provided from the top of the cylindrical container 6a along the inner wall of the cylindrical container 6a so as to be flush with the inner wall, and from the top of the cylindrical member 6b. A cylindrical electrode 4 is provided along the outer wall so as to be flush with the outer wall. In this case, the cylindrical electrode 4 is provided so as to face the cylindrical electrode 3 and to form concentric circles. Further, a dielectric liquid 5 such as silicone oil is injected into the ring-shaped sealed container 6. In this case, in this example, the dielectric liquid 5 is injected into the closed container 6 to a level where the lower ends of the cylindrical electrodes 3 and 4 are located, with the closed container 6 being held horizontally. Therefore, when the closed container 6 is kept horizontal, the lower ends of the cylindrical electrodes 3 and 4 are in contact with the level of the dielectric liquid 5. Further, the cylindrical electrodes 3 and 4 are each connected to a predetermined conductive pattern formed on the lid 2, that is, a printed wiring board.

In this example, when the closed container 6 is held horizontally as shown in FIG. 1 and tilted as shown in FIG. 2, there is a difference in the dielectric constant between the space and the dielectric liquid 5. Therefore, as the absolute value of this inclination angle θ becomes larger, the dielectric capacitance between the two cylindrical electrodes 3 and 4 becomes larger.
The relationship between the inclination angle θ and the capacitance value C between both cylindrical electrodes 3 and 4 is good as shown in FIG.

In this case, in this example, the liquid level of the dielectric liquid 5 is maintained within the ring-shaped sealed container 6 formed by the cylindrical container 6a and the cylindrical member 6b, regardless of the presence or absence of the cylindrical electrodes 3 and 4. The capacitance C changes continuously according to the inclination of the closed container 6, and the variations in the change in the capacitance C with respect to the inclination angle θ of the closed container 6 are small, so that the inclination can be detected favorably.

Further, FIGS. 4 and 5 show other examples of the present invention, and to explain the examples in FIGS. 4 and 5, FIGS. Corresponding parts are denoted by the same reference numerals, and detailed explanation thereof will be omitted. In FIGS. 4 and 5, the cylindrical container 6a in FIGS. 1 and 2 is turned upside down, and the cylindrical electrode 3 and FIG. At the same time as installing the lid 2
It is provided with a bottom cover 2a constructed in the same manner as shown in FIG.

In this case, the cylindrical electrodes 3 and 4 are immersed in the dielectric liquid 5 when the closed container 6 is kept horizontally, and when the closed container 6 is tilted, the cylindrical electrodes 3 and 4 are immersed in the dielectric liquid 5. Both cylindrical electrodes 3, 4
As the capacitance inside becomes smaller, this figure 4 and 5
It goes without saying that the same effects as in FIGS. 1 and 2 can be obtained in the illustrated example as well.

6 and 7 further show other examples of the present invention. In FIGS. 6 and 7, the outer cylindrical member 6c, the cylindrical member 6b, the bottom cover 2a, and the lid 2 form a ring-shaped sealed container 6, and the inner wall of the outer cylindrical member 6c is completely covered. A cylindrical electrode is formed to form a common cylindrical electrode 3a, and a cylindrical electrode extending from the upper part of the cylindrical member 6b to an approximately intermediate position is formed to form one differential electrode 4a, and a cylindrical electrode extending from the lower part of this cylindrical member 6b to an approximately intermediate position is formed. forming a cylindrical electrode extending to the other differential electrode 4b (in this case, one differential electrode 4b).
a and the other differential electrode 4b are insulated from each other. )
The dielectric liquid 5 is injected into the ring-shaped sealed container 6 up to the middle position.

In such examples of Figures 6 and 7, Figures 1 and 2
The same effects as in the illustrated example can be obtained, and the cylindrical electrodes are also connected to one and the other differential cylindrical electrodes 4a and 4b.
and a common cylindrical electrode 3a, by differentially connecting the cylindrical electrodes 4a, 4b, or 3, it is possible to obtain a detection output that is twice as large in response to the tilt of the closed container 6. Good tilt detection can be performed.

In this case, of course, one and the other differential cylindrical electrodes may be provided on the inner wall of the outer cylindrical member 6c, and a common cylindrical electrode may be provided on the outer wall of the cylindrical member 6b.

It goes without saying that the present invention is not limited to the above-described embodiments, and that various other configurations may be adopted without departing from the gist of the present invention.

[Effect of idea]

According to the present invention, the liquid level of the dielectric liquid 5 inside the ring-shaped closed container 6 changes continuously according to the inclination of the closed container 6, so that the change in capacitance with respect to the inclination of the closed container 6 varies. is small and can perform good tilt detection.

In addition, in the present invention, the cylindrical electrodes are used as the first and second electrodes.
When configured with a differential electrode and a common electrode, it is possible to obtain twice the detection output for the tilt of the closed container 6, and to achieve good tilt detection that is less susceptible to temperature changes. There are benefits that can be made.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing one embodiment of the capacitive tilt sensor of the present invention, and FIG.
4 and 5 are sectional views showing other embodiments of the present invention; FIGS. 6 and 7 are sectional views showing still other embodiments of the present invention; 8, FIG. 10, and FIG. 11 are cross-sectional views showing examples of conventional capacitive tilt sensors, and FIG. 9 is a perspective view showing an example of the cylindrical electrode of FIG. 10. 2 is a lid, 2a is a bottom lid, 3, 3a, 4a, 4b and 4 are cylindrical electrodes, 5 is a dielectric liquid, 6 is a ring-shaped sealed container, 6a is a cylindrical container, 6b and 6c
is a cylindrical member.

Claims (1)

[Claims for Utility Model Registration] 1. A closed container consisting of a pair of concentric cylindrical members, a pair of cylindrical electrodes formed on the upper or lower part of the cylindrical members, and a dielectric partially enclosed within the closed container. A capacitive tilt sensor, comprising: a liquid; and detects a change in capacitance between the pair of cylindrical electrodes to detect a tilt of the closed container. 2. An airtight container consisting of a pair of concentric cylindrical members, and a first and second container formed on one of the cylindrical members.
a common cylindrical electrode formed on the other side of the cylindrical member to face both the first and second differential cylindrical electrodes; and a dielectric liquid partially enclosed in the sealed container. and a capacitance change is differentially detected between the first and second differential cylindrical electrodes and the common cylindrical electrode to detect the tilt of the closed container. Capacitive tilt sensor.