JPH083421B2 - Inclination detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an object to be measured in a horizontal or gravity direction,
In particular, the present invention relates to a tilt angle detector that electrically detects a changing tilt angle of an oscillator.

(Prior Art) Conventionally, an inclination angle detector that detects the inclination of the support portion of the pendulum has been put into practical use by utilizing that the pendulum always directs in the vertical direction by the action of gravity. This is because the position of the pendulum relatively changes according to the tilt of the support portion, and therefore the tilt angle is detected by directly or indirectly electrically detecting the change in the tilt position with respect to the reference pendulum position. (Actual No. 57-94813, No. 58-177).
No. 811). Such a conventional pendulum structure detector requires a very delicate skill in processing and assembling the suspension wire portion of the pendulum and requires a high precision technique. As a result, it is expensive. In addition, the fluctuation of the position at the time of reference due to the deformation of the suspension wire portion due to the temperature change, the impact, etc. is large, and it is unavoidable that there is an error in the inclination angle detection.

(Problems to be Solved by the Invention) The present invention eliminates the inclination angle detection error with respect to temperature change, impact, etc., without requiring the advanced processing and assembly techniques found in the conventional inclination angle detectors described above. The purpose of the present invention is to provide an inexpensive and highly accurate inclination angle detector having a completely different structure from the inclination angle detector of the conventional suspension wire structure.

(Means for Solving Problems) In the inclination angle detector of the present invention, in FIG. 1 showing an embodiment, a core 2 made of a magnet is supported in a housing 1 via a magnetic fluid 3. A concave guide groove 6 for guiding the core 2 is formed on the core supporting surface of the housing 1, and the coil 4 is wound around the housing 1. Then, the coil 4 is connected to a detection circuit 5A that detects a change in the inductance of the coil.

(Operation) Since the magnetic fluid 3 gathers around the magnetic poles of the core 2, the core 2 floats above the guide groove surface 6 of the housing 1, and when the housing 1 tilts, the lowest position of the groove surface 6 curved by gravity. Move freely to. As shown in FIG. 3, when the housing 1 tilts from the horizontal by θ, the core 2 and the magnetic fluid 3 move to the lowest position and are displaced from the reference position 10, and the output corresponding to this displacement 11 is output from the coil 4. can get. If this displacement 11 is d and the radius of curvature of the curved guide groove surface 6 is R, then d = θR holds,
On the other hand, since the inductance L of the coil 4 changes linearly with respect to the displacement d, the inclination angle θ of the housing 1 can be detected by detecting the change amount of the inductance L of the coil 4 by the detection circuit 5A. .

(Embodiment) FIG. 1 shows the structure of an inclination angle detector according to an embodiment of the present invention. This inclination angle detector is composed of, for example, a core 2 made of a bar-shaped magnet and a magnetic pole around the core 2. A magnetic fluid 3 for holding and floating the core 2 so that it can move freely, and a container (housing) made of a non-magnetic material that is a high resistance or an insulator for housing the core 2 and the magnetic fluid 3. ) 1 and the reference position of the core 2 arranged around the container 1
2 spaced apart from each other with the same number of turns and size to detect displacement 11 (Fig. 3) from 10 (Fig. 3)
Each coil 4 and a detection circuit 5A connected to the coil 4 for measuring the terminal voltage of each coil 4 and outputting an electric signal corresponding to the inclination angle of the container 1 are provided. Further, in the embodiment shown in FIG. 1, the two coils 4 are connected in series to an alternating constant current source S.

By the way, the outer shape of the container (housing) 1 is, for example, a cylindrical shape, and the mounting surface of the core 2 inside thereof has a semicircular cross section (second
A guide groove 6 of FIG. (A) is formed in the longitudinal direction of the housing, and the guide groove 6 has a curved shape (curvature radius R) so as to be concave upward in the vertical direction as shown in FIG. ing.
The groove 6 formed in the container 1 may have a V-shaped cross section as shown in FIG. 2 (b), and if it has a shape that can function as a sliding guide for the magnetic fluid 3, other than a circle or a V-shape. In addition, any cross-sectional shape such as a trapezoidal shape or an elliptical shape may be used.

With this arrangement, since the magnetic fluid 3 gathers around the magnetic poles of the core 2, the core 2 floats above the groove surface of the container 1 and can freely move to the lowest position by gravity when the container 1 tilts. it can. Then, when the core 2 is located at the center of the two coils 4 as the reference position 10 (FIG. 3), when the container 1 is tilted by an angle θ from the horizontal direction as shown in FIG. 3, the core 2 and the magnetic fluid 3 Slides to the lowest position and moves from the reference position 10 by a displacement 11. This displacement 11 is d,
When the radius of curvature of the curved groove surface 6 is R, the relationship of d = θR is established, and the displacement 11 is proportional to the tilt angle θ. By the way, when the displacement 11 of the core 2 is represented by d, the inductance L of each coil 4 changes linearly as shown in FIG. 8 (L∝d). The solid line in FIG. 8 shows the change in the inductance of one coil 4, and the dotted line shows the change in the inductance of the other coil. Inductance increases when the core enters the coil and conversely decreases when it exits the coil. Therefore, a voltage change corresponding to the displacement 11 occurs in the voltage between the terminals of each coil 4, so that the difference between these two terminals has the characteristic shown in FIG. be able to.

FIG. 5 shows the configuration of another embodiment of the present invention, in which each coil 4 is connected in parallel to the AC constant voltage source S, and the current flowing through each coil 4 passes through the current-voltage conversion circuit 5B. It is designed to be detected by the detection circuit 5A. Along with the inclination of the container 1, a current change corresponding to the displacement 11 occurs in each coil 4, and the difference between these two currents also has a characteristic proportional to the inclination angle as shown in FIG. The angle θ can be obtained.

FIG. 6 shows the construction of another embodiment of the present invention, in which case the coil 4 constitutes the container 1 so as to constitute a differential transformer.
Wrapped around. The coil 4a is a primary coil, which is excited by the AC constant current source S, and the coil 4b is a secondary coil, which outputs a voltage corresponding to the displacement 11 of the core 2. Since the difference between the output voltages of the secondary coil 4b has the characteristic shown in FIG. 4, the inclination angle θ can be obtained in the same manner.

FIG. 7 is a sectional view of a container (housing) 1 according to another embodiment of the present invention, and any of the above-mentioned embodiments can be used as a detection circuit system. In this case, the inner surface of the container 1 is a barrel-shaped curved surface formed by rotating an arc of radius R about the cylindrical axis of the container 1 or a part thereof, and this inner surface acts as the guide groove surface 6. The feature of this embodiment is that even if the container 1 rotates about its cylindrical axis, it does not affect the detection accuracy of the inclination angle θ of this axis with respect to the horizontal plane.

Although several embodiments have been shown above, it will be apparent that many other modifications are possible.

(Effects of the Invention) As described above, the inclination angle detector according to the present invention causes the displacement of the core due to the inclination with a simple structure in which the core made of the magnet and the magnetic fluid are housed in the housing having the curved inner surface. Since this displacement is converted into an electric quantity by the coil around the housing, it is possible to provide an inexpensive and highly accurate inclination angle detector without requiring advanced processing and assembly techniques.
There is also an advantage that the sensitivity to inclination can be freely set by changing the radius of curvature R. This tilt angle detector can detect the tilt of the object to be measured with high accuracy, and feedback control can be applied to the tilt angle adjustment drive unit of the object or other objects related to the detected electric signal. The detector can be used as an inexpensive element for automatic control or remote control. The inclination angle detector has an extremely small inclination angle detection error with respect to temperature change, impact, etc., as compared with the conventional one.

[Brief description of drawings]

FIG. 1 is a block diagram showing a tilt angle detector according to an embodiment of the present invention, and FIGS. 2 (a) and 2 (b) are sectional views of only the container along line II-II in FIG. 3 is an explanatory view showing the state of the core at the time of tilt, FIG. 4 is a tilt angle vs. output characteristic diagram of the detection circuit,
FIG. 5 is a block diagram of another embodiment, FIG. 6 is a block diagram of another embodiment, FIG. 7 is a sectional view of a housing of another embodiment, and FIG.
The figure is a core displacement vs. inductance change characteristic diagram of the coil. 1: container (case), 2: core consisting of magnet, 3: magnetic fluid, 4:
Coil, 4a: primary coil of differential transformer, 4b: secondary coil of differential transformer, 5A: detection circuit, 5B: current-voltage conversion circuit,
6: Guide groove, 10: Reference position, 11: Displacement, S: Power supply

Claims (3)

[Claims] 1. A core made of a magnet housed in a housing and displaced according to the inclination of the housing, a coil wound around the housing so as to surround the core, and a core connected to the coil. A tilt angle detector comprising a detection circuit for detecting the amount of change in the inductance of the coil according to the displacement to detect the tilt angle of the housing, the tilt angle detector being provided between the core and a core supporting surface of the housing. Inclination angle detector characterized in that a magnetic fluid is interposed in the core and a guide groove surface curved in a concave shape is formed on the core support surface as a core sliding guide. 2. The tilt angle detector according to claim 1, wherein the guide groove surface has a V-shaped, trapezoidal, or elliptical cross-sectional shape. 3. A guide groove surface curved in a concave shape is formed from a curved surface of a barrel formed by rotating an arc around a shaft of a housing or a part thereof, and a guide groove surface is formed. Inclination detector