JPS5995422A - Detector of rotary displacement - Google Patents

Abstract

PURPOSE:To obtain an output which is stable with a change in temp. without disturbing a system to be measured by providing the 1st and the 2nd immobile stators and a rotor, connecting a power source to both electrodes of the 1st stator and connecting an output detector to both electrodes of the 2nd stator. CONSTITUTION:The 1st and the 2nd stators 1, 2 consisting of an insulating material are fixed in parallel apart an insulating distance from each other. Two sheets of electrodes 4, 5 each of which is formed of a conductor having a semicircular shape and which are connected to an AC voltage power source are pasted on the inside surface of the 1st stator 1 in such a way that the mutual chord parts 4a, 5a face to each other in parallel apart an insulating distance. On the other hand, two sheets of electrodes 7, 8 each of which is formed of a conductor having a semicircular shape and which are positioned across a load impedance 6 are pasted on the inside surface of the 2nd stator 2 in such a way that the mutual chord parts 7a, 8a face to each other in parallel apart from an insulating distance. The 1st and the 2nd stators are fixed with a deviation in phase by 90 deg. so that the electrodes pasted on the inside surfaces of both stators face to each other and that the respctive chord parts 4a, 7a (or 5a, 8a) are right angled to each other.

Description

[Detailed description of the invention] The present invention relates to a rotational displacement detection device.

There are two types of rotational displacement detection devices: a contact type that has a sliding part between a rotating part and a fixed part, and a non-contact type that does not have a sliding part.
Among these, the non-contact type is often advantageous because the torque required for rotation is small and there is no wear due to sliding.

Currently, magnetic methods are widely used as non-contact types, and these include methods using magnetoresistive elements and magnetic equilibrium methods. The former has a limited direct range and a large temperature drift in the output, making compensation difficult. In the latter case, there is no contact between the rotating part and the fixed part, but a magnetic force is generated between the movable magnet and the fixed saturable core due to rotational displacement, which makes it difficult to detect rotational displacement with light torque. is undesirable because it causes disturbance to the system under test.

The purpose of the present invention is to provide a capacitive rotary displacement system that has a wide linear range, is non-contact, has a light torque, does not cause any disturbance to the system under test (and can provide stable output against temperature changes). The purpose is to provide a detection device.

The present invention will be explained in detail below based on embodiment figures.

FIG. 1 is a schematic diagram of a rotational displacement detecting device according to the present invention, in which reference numerals 1 and 2 indicate first and second stators each having a circular shape and made of an insulating material, and are spaced apart from each other by an insulating distance. fixed in parallel.

On the inner surface of the first stator 1, two semicircular conductor electrodes 4 and 5 connected to an AC voltage power source 3 are arranged at a long arc portion 4.
A and 5a are attached with insulation distance devices so that they face parallel to each other. On the other hand, on the inner surface of the second take 2, two semicircular conductor electrodes 7 and 8 spanning the load impedance 6 are pasted so that their arc parts 7a and 8a face each other in parallel with an insulation distance If. It is being Also, these first. The second stator is fixed so that the electrodes attached to the inner surfaces of both stators face each other and are 90 degrees out of phase so that the arc parts 4a and 7a (or 5a and 8a) are at right angles to each other. has been done.

Reference numeral 9 denotes a circular rotor, the central insulating part 11a of which is fixed to the rotating shaft 10, and divided into four parts in the circumferential direction, each having two symmetrical fan-shaped insulating members 11.
．． 11 and conductors 12 and 13 are alternately formed. In addition to the embodiment shown in FIG. 1, as shown in FIGS. 2 and 3, the rotor 9 has a circular insulating member 11 to which a rotating shaft 10 is fixed to the central portion 11a, and a circular insulating member 11 is mounted on both sides of the member 110. Fan-shaped conductor foils 12a, 12b and 13a, 13b are pasted facing the conductor foil 12a.

Connection 2 between 12b and between 13a and 13b
1 and 22 may be applied to integrate the two.

Further, the rotating shaft 10 passes through a center hole 14.15 made in the center of a disc made up of a stator and electrodes, and as the rotating shaft 10 rotates, the rotor 9 moves between the stators 1 and 2.
It has a structure that allows it to rotate parallel to the stator at an intermediate position. The rotating shaft 10 is rotated by displacement of a float such as a liquid level gauge or a flow meter (not shown).

In addition, the voltage generated across the load impedance is
It is output as an output voltage Vout to a differential amplifier circuit, etc., which will be described later.

In order to facilitate understanding of the wiring connections shown in FIG. 1, FIG. 4 is a circuit diagram summarizing the wiring connection method shown in FIG. 1.

FIG. 5 shows an example of a circuit configuration actually used in the rotational displacement detecting device according to the present invention, whereby a stable voltage is supplied between the electrodes 4 and 5.

In the figure, 16 is a stabilized voltage source, 17 is an oscillation circuit, and 18 is a stabilized voltage source.
1 is a differential amplifier circuit, 19 is a smoothing circuit, and 20 is a switching element.

The structure of the present invention has been described above, and its effects will now be described.

Let us now assume that the central angle of the sector-shaped conductors 12 and 13 is 200 degrees. Initially, each conductor was at the position of the broken line in Fig. 6, but after that,
If it is rotated by an angle θ in the direction of the arrow and comes to the position of the imaginary line in FIG. r”) (French -θ),,,,,, (1)
d.

Here, S is the dielectric constant of the material between the electrode and the conductor, d is the distance between each electrode and the conductor, R is the outer diameter, and r is the inner diameter.

The capacitance C2 of the capacitor formed by the overlapping of the sector-shaped conductor 12 and the electrode 5 is as follows.

The capacitance C3 of the capacitor formed by the overlap between the electrode 5 and the sector conductor 13, and the capacitance C4 of the capacitor formed by the overlap between the sector conductor 13 and the electrode 4 are as follows.
Due to symmetry, CI=03. C=C4L, and it becomes.

The capacitance C of the capacitor formed by the overlap between the sector conductor 12 and the electrode 7, and the capacitance C6 of the capacitor formed by the overlap between the sector conductor 13 and the electrode 8 are:
If the rotation angle range of the rotation axis 100 is appropriately selected, the area of the overlapping portion can be made constant, so it can be set as C5=C6=Cs.

Equation (1) (2bar3) (4) If we set K, then C+ = C3= Co -re, y, ,
,, (7) C:z = C4= Co + r a
, , -0,-(8). However, the formula (
7) In (8), since Co and r are constants, the capacitances C1 to C4 are given by linear functions of the rotation angle θ.

By the way, as shown in the equivalent circuit of FIG. 4, when an AC voltage of angular frequency ω and amplitude E is applied between the electrodes 4 and 5, the output voltage Vnu generated across the load 6 with impedance ZL is
For t, the following relationship is obtained. Here, 5 indicates an imaginary unit.

Equation (6) is derived from Equations (5) and (6). In equation (6), if the amplitude E is constant, Vout is
This shows that it does not depend on ε, d, cAJ, etc. at all, and is proportional only to O. Note that a constant amplitude E can be realized by the circuit configuration shown in FIG.

In this way, the rotational displacement detection device according to the present invention can extract the IJ air output voltage Vout with respect to the rotation angle θ, and since a magnet or the like is not used in the detection section, it is contactless and lightweight. Torque does not cause any disturbance to the system being measured, and it is possible to obtain a stable output against temperature changes.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a rotational displacement detection device according to the present invention, and FIG.
The figure is a diagram of another embodiment of the rotor, and Figure 3 is III- of Figure 2.
Figure 4 is an equivalent circuit diagram of Figure 1,
The figure is a block diagram showing an example of a circuit actually used in the present invention, and FIG. 6 is a diagram showing the positional relationship between electrodes and conductors. In the figure 1 First stator 2 Second stator 3 AC power supply 4, 5, 7.8 Electrode 6 Load
9 Rotor 10 Rotating shaft 11 Insulating member 12.1
3 Sector-shaped conductor 14, 15 Hole 16 Stabilized voltage source 17 Oscillator circuit 18 Differential amplifier circuit
19 Smoothing circuit 20 Switching element 21
．． 22 Wiring Department Member Applicant Tokyo Keiso Co., Ltd. Agent Patent Attorney 1) Kiyomi

Claims (1)

[Claims] An immovable first electrode, in which two divided electrodes are respectively provided on opposing surfaces, and the opposing electrodes are arranged in common phase with each other.
A stator, a second stator, and a center portion attached to a rotating shaft passing through at least one of the stators, located between the first and second stators, and electrodes and an insulating portion alternately arranged in a circumferential direction. What is claimed is: 1. A rotational displacement detection device, comprising: a rotor, wherein a power source is connected to both electrodes of the first stator, and an output detector is connected to both electrodes of the second stator.