JPH0726649Y2 - Inclination sensor using magnetic fluid - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention relates to a tilt sensor, and more particularly to a tilt sensor having a simple structure using a magnetic fluid.

[Prior art]

Conventionally, various systems have been proposed as a tilt sensor using a magnetic substance that behaves as a fluid, that is, a magnetic fluid known by a trade name such as ferricoid. One example is shown in FIG. In this tilt sensor, a magnetic fluid (not shown) is enclosed in a container (1) composed of a ring-shaped tube so that the liquid surface forms a horizontal plane, and a detection coil ( 2a), (2b), (2c), ... are wound. With this configuration, when the container (1) is tilted, the volume distribution of the magnetic fluid changes, and the magnetic resistance of each of the detection coils (2a), (2b), (2c) ,. The inclination of the container (1) can be known by detecting the electric signal output from each detection coil by utilizing the phenomenon.

However, in such a conventional detection mechanism, in order to realize a simple detection method of accurately displaying the inclination of the container by the current flowing through each detector when the same voltage is applied to each detection coil, the same detection method is used. The specifications of the detection coils must be arranged at equal intervals, which requires assembly and adjustment work and complicates the assembly structure. As described above, in the conventional tilt sensor using the magnetic fluid, if the structure is simplified (the same specifications of the detection coils and the accuracy of the arrangement are not required), the detection signal processing is burdened,
On the contrary, there is a problem that if the signal processing is attempted to be simple, the structure becomes awkward (the same specifications of the detection coils and the accuracy of the arrangement are required).

In addition, in such a conventional ring-shaped magnetic fluid tilt sensor, an error occurs due to the difference in the position of the maximum tilt point even with the same tilt amount, and it is also attempted to improve accuracy and obtain a large measurement range. Then the radius of the ring is relatively small,
The radius of the pipe needs to be large, and in addition,
If the coil diameter is also taken into consideration, there is a problem in production, and therefore there are problems such as the measurement range being limited to a small range.

[Problems to be solved by the invention]

Except for such drawbacks of the prior art, the present invention has a simple processing of the detection signal and a simple structure, and there is no error due to the difference in the position of the maximum inclination point. It is an object of the present invention to provide a tilt sensor using a magnetic fluid having a large measurement range.

[Means for solving problems]

The inclination sensor using the magnetic fluid of the present invention has a container (1) whose inner surface is a linear cylinder, and a liquid surface in the cylindrical container, as shown in the embodiment having the basic structure in FIG. Has a magnetic fluid (3) that is enclosed in a substantially half amount so as to maintain a horizontal surface, and has a plurality of detection coils (2a, 2b) arranged so as to wind the cylindrical container. The outer circumference of the detection coil serves as a bobbin around which the detection coil is wound, and partition walls that restrict both sides of the detection coil are integrally formed.

[Action]

When the container (1) is tilted, the distribution of the magnetic fluid (3) changes, and the magnetic resistance of the detection coils (2a) and (2b) changes. Therefore, if the same AC voltage is applied to each of the detection coils (2a) and (2b), a difference occurs in the flowing current.
The inclination angle can be known from this difference.

〔Example〕

 Next, the contents of the embodiment shown in FIG. 2 will be described.

The figure shows the structure of the tilt sensor of the present invention. (1) is a substantially cylindrical container made of plastic or glass, and a magnetic fluid (3) enclosed by a known technique so as to fill about half of the container.
With a built-in detection coil S ₂ and S ₂ with an interval on the outer circumference.
Is wound and fixed. S ₁ is an exciting coil.

Now, if the container (1) is tilted, the distribution of the magnetic fluid (3) changes and the magnetic resistance of the detection coil changes. Therefore, by simply detecting the current of the detection coil generated when the same voltage is applied, the container can be easily You can know the slope.

At this time, there are no special restrictions on the shape or material of the container (1),
It does not matter as long as the surface of the built-in fluid can maintain a horizontal surface, but if it is made of a plastic cylinder with high mass productivity,
It is advantageous in production. Further, if this is made of a transparent body, the distribution state of the built-in magnetic fluid can be visually observed, which is convenient for practical use. The winding method of the detection coil does not matter. Moreover, since the detection signal is obtained from the two detection coils, even if they do not have the same specifications, the inclination can be accurately detected by simple signal processing. Of course, the number of detection coils is not limited to two, but for the purpose of the present invention, it is desirable to use two.

When two detection coils with the same specifications are arranged symmetrically with respect to the axial center of the cylindrical container and these detection coils are used as a differential transformer by using an exciting coil, they must be reversed so that their output voltages cancel each other out. When connected in pole series, if this inclination sensor is horizontal, no voltage difference will occur between the other terminals of both detection coils, and there will be a straight line between the inclination angle and the voltage difference between these terminals. Therefore, the obtained voltage difference can be directly used as a signal representing the amount of inclination.

The embodiment shown in FIG. 2 satisfies the above basic structure and further simplifies the structure and facilitates use of the detection signal. That is, the container (1) has an integral structure that also serves as three coil winding bobbins as shown in the figure.
If this is used as a plastic molded product, it is advantageous in terms of price and the coil winding work is easy. As a coil, an exciting coil S ₁ is provided on a bobbin at the center of the container (1), detection coils S ₂ and S ₃ are provided on both sides of the bobbin, and both detection coils S ₂ and S ₃ are connected in reverse pole series. Connected as a differential transformer system. Therefore, the obtained signal has high accuracy, and the output characteristic shows linearity.

Although the present invention has been described with respect to two embodiments, it will be apparent to those skilled in the art that many modifications other than these embodiments are possible.

It should be noted that it is possible to easily detect the inclination in any direction by using the two inclination sensors of the present invention so as to be orthogonal to each other.

[Effect of device]

As is apparent from the above description of the embodiments, the inclination sensor of the present invention has the advantages that not only the detection accuracy can be improved, but also the structure is simple and the manufacture and assembly are easy.
Further, since the detection signal can be used without troublesome processing, there is an effect that the product price can be reduced. Further, compared to the conventional ring-shaped one, the error due to the movement of the maximum inclination point does not occur, and in the linear cylindrical shape like the present invention, the measurement range is the relationship between the pipe diameter and the detection coil. Since it is determined by, the design is free, and high accuracy can be maintained and a large measurement range can be secured.

Moreover, by configuring the cylindrical container with a transparent body, the distribution state of the built-in magnetic fluid can be visually confirmed, which is extremely convenient in practical use. The inclination angle can be detected with sufficient accuracy by disposing the two detection coils at intervals, and further, by providing the exciting coil between the two detection coils, the detection coil can be detected. A signal can be taken out without applying any voltage to it, and by connecting these two detection coils in series with opposite poles, a signal with high accuracy and good linearity can be taken out. Further, by integrally forming the cylindrical container and the bobbin for each coil, it is possible to make the coil winding work easy and inexpensive.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the basic structure of the present invention, FIG. 2 is a longitudinal sectional view of a tilt sensor of the same embodiment, and FIG. 3 is a plan view of a tilt sensor of a conventional example. 1: Vessel, 2a, 2b, S ₂ , S ₃ : Detection coil 3: Magnetic fluid, S ₁ : Excitation coil

Claims (3)

[Scope of utility model registration request] 1. A container having an inner surface of a linear cylinder, a magnetic fluid in which approximately half of the liquid surface is enclosed in the cylindrical container so that the liquid surface maintains a horizontal surface, and the cylindrical container is arranged so as to be wound. Having a plurality of detection coils provided, the cylindrical container is a bobbin for winding the above-mentioned detection coil,
A tilt sensor using magnetic fluid, characterized in that partition walls for restricting both sides of the detection coil are integrally formed. 2. In the claim 1 of the utility model registration claim,
Inclination sensor using magnetic fluid, characterized in that the cylindrical container is composed of a transparent body 3. Claim for utility model registration claim 1 or 2
In the paragraph (2), a tilt sensor using a magnetic fluid, characterized in that the two detection coils are connected in reverse polarity in series.