JPS58176514A - Rotation position detector - Google Patents

Abstract

PURPOSE:To obtain a high-precision detector of simple structure which is assembled easily by obtaining variation in facing area between a fixed electrode and a rotary electrode which is displaced according to the rotary displacement of a body to be detected in the form of electric variation, and thus detecting the rotary displacement. CONSTITUTION:When a rotating shaft 1 rotates by an angle theta according to the rotary displacement of the body to be detected, the rotary electrode 2 also rotates around the shaft 1 by the angle theta to shift in relative position from the fixed electrode 4 by the angle, and the facing area between the electrodes 2 and 4 is proportional to the angle theta. The magnetic circuit consiting of an energizing coil 9 varies in magnetic resistance with the facing area between the electrodes 2 and 4, and the magnetic resistance is in inverse proportion to the facing area. Therefore, a voltage induced at a detection coil 10 is proportional to the angle theta, so the voltage value is found to detect the rotary displacement of the body.

Description

[Detailed Description of the Invention] Description of the Technical Field 1 The present invention relates to a rotational position detector, and is designed to extract changes in the opposing area of plate-shaped electrodes having no coils in the two-rotation portion as an electrical output. This invention relates to a rotational position detector.

[Description of Prior Art 1] Fig. 1 is a diagram showing the winding configuration of a resolver electric machine used as a conventional rotational position detector, in which the stator winding 8. -8
s is a single phase, and the rotor winding has two windings, -FL and -R, which are electrically shifted by 90 degrees from each other. An excitation voltage Beta is applied to the stator windings S, -S, and thereby an output voltage E□181m is generated at the rotor windings 's ``m, Rv ''a. Excitation voltage g at this time,
FIG. 2 shows the relationship between lfi, the output voltage ``lIa+Els&'', and the rotation angle θ of the rotor, and this relationship is expressed by the following equations (11, (2)).

E mu = K, I Ellscos θ ・・
...(1) Easa = K, E,, 3sinθ
(K is a constant) -.---+21 Therefore, by detecting the output voltage Eall + E11% of the rotor winding, the rotational angle, that is, the rotational position of the object to be detected can be detected.

@3 Figure 2 is a diagram showing the winding configuration of a synchro electric machine used as a conventional rotational position detector. This means that when an excitation voltage E1111 is applied to the rotor windings R, --, three-phase outputs are generated to the stator windings 88-S, -S, respectively, depending on the rotational position of the rotor. Ba1l is obtained.

Therefore, the rotational position can be detected for the three-phase output El 11 + g + g, pull 1:.

This is a conventional rotational position detector. Resolver'I
I1. Both machines and synchro electric machines use voltage induced in the windings wound around the rotating shaft to detect the rotational position.

Therefore, since the rotary position detector having such a structure is a single-rod motor, it requires precise processing technology and has a complicated structure, which results in poor accuracy.

OBJECTS OF THE INVENTION] An object of the present invention is to eliminate the above-mentioned drawbacks, to obtain a rotational position detector that has a simple structure, is easy to assemble, and has high detection accuracy.

U Structure of the Invention J An embodiment of the present invention will be explained below with reference to the drawings. Fourth
In FIG. 62, 1 is a rotating shaft that is mechanically coupled to the object to be detected whose rotational position is detected and rotates with the rotation of the object to be detected. are integrally connected. This rotating electrode 2 is shown in FIG.
It is provided at a position approximately 180' opposite to the circumference 9 of the rotating shaft 1 and has a fan shape. 3 is a fixed frame that is approximately U-shaped.

This "fixed frame 3-" is formed with two plate-shaped fixed electrodes 4a*4b which sandwich the rotating electrode 2 from both sides with an appropriate gap g+-g*.

As shown in FIG. 5, the fixed electrodes 4a14b are fan-shaped and have approximately the same dimensions as the rotating electrode 2, and two electrodes 4a-1148 are arranged at opposite positions of 180' on one side.
-2, 4b-1, 4b-2, a total of four sheets are provided. The front rotating shaft l is rotatably supported at one end by the fixed frame 3 via a bearing 5. Reference numeral 6 denotes a support body which is coupled to one end of the fixed frame 3 and forms a crushing magnetic circuit, and rotatably supports the other end of the rotating shaft l via a bearing 7. Reference numeral 8 denotes a spool made of an insulator fixed in a window 8a of the fixed frame 3 so as to surround the rotating shaft 1. Inside this spool 8 is an excitation coil 9 so as to surround the rotating shaft 1, and an excitation coil 9 on the outside thereof. A detection coil IO is wound around the spool 8. Since an appropriate gap is formed between the spool 8 and the rotating shaft 1, rotation of the rotating shaft 1 is not hindered.

An alternating current voltage is applied to the excitation coil 9C from a power source (not shown). This results in rotating shaft) 1 - Bearing 5 - Fixed frame 3 - Fixed electrode 4 - Rotating electrode 2 - Rotating shaft)
A magnetic circuit as shown by the arrow in the figure is formed by one closed loop. The magnetic flux flowing through this magnetic circuit causes the detection coil 1 to
A voltage is induced at 0.

[Operation of the invention] Next, the operation of the present invention will be observed. When the rotational displacement of the detected object is 0, that is, when the rotation angle is 0, Fig. 6 1: Shows C.
- The rotating electrode 2 and the fixed electrode 4 are in a state where they almost overlap (
= Yes, and the opposing area of both electrodes 2.4 at that time is maximum. When the C2 detection object is simultaneously rotated by a predetermined angle, the rotating shaft 141 is rotated by a predetermined angle accordingly. If the rotating shaft 1 rotates, for example, by six angles, the rotating electrode 2 will also rotate by an angle θ about the rotating shaft 1, and its relative position with respect to the fixed electrode 4 will shift by the angle θ, as shown in FIG. In this state, the opposing area of the rotating electrode 2 and the fixed electrode 4, ie, the overlapping area S, is approximately proportional to the rotation angle θ as shown in the following equation (3).

8: K, 19 (K, is a constant) ・・・・・・・・・
(3) The magnetic resistance R of the magnetic circuit formed by the excitation coil 9 changes as the opposing area S between the rotating electrode 2 and the fixed electrode 4 changes. It is inversely proportional to the facing area 8 as shown in the following equation (4).

1 R= K, (K is a constant) ・・・・・・・・・
・(4)■ On the other hand, the voltage V induced in the detection coil 10 is the voltage V induced in the excitation coil 9.
As long as is excited with a constant alternating current, it will be proportional to one rotation angle θ as shown in the following equation (5).

-11 cm for v-, - -f x θ (K is a constant) (5) Therefore, to find the value of the voltage V induced in the detection coil 10, and C2. Therefore, the rotation angle θ of the rotating shaft 1, that is, the rotational displacement (position) of the detected object can be detected.

Further, when the rotation axis l is displaced ΔX in the axial direction indicated by arrow X in FIG. 4, gs-ΔX occurs on one side of the rotating electrode 2, but g! on the other side. +ΔX cancels the mutual 6-gap conversion, and no change in the overall gap length occurs.

Other Embodiments] In the tenth embodiment, the rotating electrode 2 and the fixed electrode 4
The rotating electrode 2 may have a substantially fan-shaped shape 1 as shown in FIG. 7C. Shape like this (:
Things to do 1; Detection coil 101' Knee II! The generated voltage waveform can be changed9, and the detection form can be changed.

Furthermore, as shown in FIG. 8, it is also possible to increase the output as a multiphase output by increasing the number of electrodes. , U Effects of the Invention J As explained above, C2 According to the present invention, a rotating shaft that performs a rotational displacement according to the rotational displacement of a rotated body, and a rotating electrode that is displaced accordingly. , and a fixed electrode whose opposing area with the rotating electrode changes according to the displacement of the rotating electrode, and the change in the opposing area between the rotating electrode and the fixed electrode is extracted as a change in electrical output and the rotational displacement of the detected object is detected. Since the structure is now detected, there is no need for the complicated structure of the coil in the rotating part as in the past, and the mechanical strength is strong.Also, the gap length as the magnetic resistance of the magnetic circuit is always constant, so the structure is Is it easy to assemble and process? A rotational position detector that is easy to use and has high detection accuracy can be obtained.

[Brief explanation of the drawing]

Figure 1 shows the winding configuration of a conventional resolver electric machine.
FIG. 2 is a characteristic diagram, FIG. 3 is a winding diagram showing the winding configuration of a conventional synchro electric machine, FIG. 4 is a sectional view showing a rotational position detector according to an embodiment of the present invention, and FIGS. FIG. 6 is a side view of the main part, and FIGS. 7 and 8 are side views of the main part showing other embodiments of the present invention. l...Rotating shaft 2...Rotating electrode 3...Fixed frame 4...Fixed electrode 5.7...Bearing
8... Spool 9... Excitation coil 10
...Detection coil g+2g goose...Gap (7317) Representative patent attorney Kensuke Chika (and 1 other person) 3rd! i! 4oL2 Figure 7 Figure 8

Claims (5)

[Claims] (1) A rotating shaft that performs the same rotational displacement according to the rotational displacement of the rotated body, a rotating electrode that is displaced with the rotation of this rotating shaft, and a rotating electrode that rotates due to the displacement of this rotating electrode. A rotational position detector that detects rotational displacement of an object to be detected by detecting a change in electrical output based on a change in the opposing area between the rotating electrode and the fixed electrode. (2) A rotational position detector according to claim #I1, characterized in that a change in the opposing area between the rotating electrode and the fixed electrode is extracted as a change in magnetic resistance in a magnetic circuit. (3) Il! The rotational position detector according to claim 1. (4) A co-rotating position detector according to any one of claims 1 to 3, characterized in that fixed lucid poles are provided on both sides of the rotating electrode. (5) A rotational position detector according to any one of claims 1 to 3, characterized in that rotating electrodes are provided on both sides of a fixed electrode.