JPS61124806A - Revolution angle detector - Google Patents

Abstract

PURPOSE:To obtain a wide measuring range detector of simple construction, by installing opposedly a metallic sheet the width of which changing proportionally to its center angle and other metallic sheet and detecting the opposed area of both sheets by connecting one of them to a rotating unit. CONSTITUTION:A metallic sheet 6 on which a radius direction width changes continually proportional to the center angle is fixed on a supporting board 7 and made to face a metallic sheet 9 mounted on other supporting board 10. And, on one of these boards 7, 10, a rotating shaft 8 is fixed for interlinkage with a rotating unit and relative rotation is caused on the both metallic sheets, and an area of the opposed parts of the both metallic sheets is detected for detection of the rotation angle. Change of the opposed area of the both metallic sheets may be detected by change of electrostatic capacity. This arrangement gives free choice of detecting sensitivity.

Description

[Detailed description of the invention] [Field of application of the invention] The f! A relates to a rotation angle detector for detecting rotation angles of rotating parts of various machines and devices.

[Background of the invention]

The rotation angle detector is indispensable not only for simply measuring the rotation angle but also for performing various controls based on the rotation angle of the rotating part. Rotation angle detector assembly, related tIC construction between a movable element connected to a rotating shaft and a stator that moves, and is classified into a contact type in which both contact and a non-contact type in which both do not contact. be done. Generally, in the case of a mechanism in which a rotating part is subjected to vibration, a CtS non-contact type rotation angle detector is often used.

Is the non-contact rotation angle detector rc well known? There is a differential transformer type, which is widely used because it has high accuracy. However, when designing this differential voltage transformer, the size and arrangement of the primary and secondary coils must be precisely configured.
Moreover, there was a drawback that the measurement range was limited. In order to eliminate such drawbacks, capacitive rotation angle detectors have been proposed. I will explain this next time.

FIG. 4 is a side view of a conventional capacitive rotation angle detector. In the figure, 1 is a rotating shaft, 2 is a semicircular mover attached to the rotating shaft 1, 3 is a semicircular stator opposite the mover 2, and 4 is a stator 3 It is a conducting wire that is connected to the wire and extracts the signal. The mover 2 and the stator 3 are formed of semicircular metal plates. FIG. 5 is a positive If diagram of the mover and stator. When the rotating shaft l is rotated in the direction of the arrow IIC from the state shown in FIGS. 4 and 5, the mover 24 rotates together with the rotating shaft l and is inserted between adjacent stators 30. Now, assuming that the mover 2 and stator 3 are electrodes, the insertion of the mover 2 causes a gap between the mover 2 and the stator 3.
Overlapping portions of C are formed to generate capacitance. Since the area of the molded part changes according to the rotation of the rotation axis l, the value of the generated capacitance will eventually be a value corresponding to the rotation angle of the rotation axis l, and the capacitance of the conductor 4 (more The value of is taken out and the rotation angle is detected.

Such rotation angle detectors manufactured by capacitors have a much simpler structure and lower cost (compared to the differential transformer type), and are cheaper to manufacture, but the measurement range is distorted. Almost 180 degrees K
The drawback 12 that the measurement range is limited is still not eliminated.

[Object of the Invention] An object of the present invention is to provide a rotation angle detector which eliminates the above-mentioned conventional drawbacks, has a simple structure, and can widen the detectable angle range.

[Summary of the invention]

In order to achieve the above object, the present invention arranges a fifth metal plate along the periphery of a circle, and the shape of this 1Ffl metal plate is such that the width measured along the radial direction of the circle is It has a shape that changes continuously in proportion to the angle of the center of the circle, and there is a second metal plate opposite to a part of the first metal plate.
A metal plate is arranged, and either the gx metal plate or the second metal plate is fixed to the rotating shaft. It is characterized in that the width of the first metal plate always changes when the shaft is rotated.

[Embodiments of the invention]

Hereinafter, the present invention will be explained based on the illustrated embodiments.

FIG. 1 is a plan view of a stator and a movable element of a rotation angle detector according to an embodiment of the present invention. In the figure, 6 is a stator formed of a metal plate, 7 is an insulating support plate that supports the stator 6,
7as is a center opening, and 8 is a moving member formed of a metal plate that interlocks with the rotating shaft 8, which is arranged perpendicularly to the plane of the drawing with its center point Oc coinciding with the rotating shaft 8. The stator 6 is arranged on a circumference centered on point 0, and has a shape such that the distance d measured along the radial direction of point 0 changes continuously from the maximum width part 6a to the minimum width part 6b. is formed. Then, assuming that the position of the maximum width portion 6a is the reference position 0°, the width d
The change is inversely proportional to the increase in angle from the reference position 0° in the direction of arrow B.

This change is formed using the inner edge 6d of the stator 6. Minimum width portion 6btz reference position θ. It is located at an angle of 270 degrees as measured from the direction of arrow B.

The mover 9 is arranged facing the stator 6 with a predetermined distance therebetween. The shape of the mover 9 is a rectangle long in the radial direction, and its radial dimension l is larger than the width of the maximum width portion 6a of the stator 6, and the dimension W in the direction perpendicular to the radial direction is appropriately ( Selected.

The outer portion 9a of the mover 9 does not become inside the outer edge 6C of the stator 6 even when the mover 9 moves in conjunction with the rotating shaft 1fc.

FIG. 2 is a side view of the rotation angle detector according to the embodiment of the present invention. In the figure, the same parts as in FIG. 1 are given the same reference numerals. lo is a support plate made of an insulator, and the rotating shaft 8
The movable member 9 is supported on its inner surface. The lower part of the rotating shaft 8 protrudes through the central opening 7a of the support plate 7 in a non-contact manner. X t1 shows the appropriately selected interval between the stator 6 and the mover 70.

Now, when the rotary shaft 8 rotates, the support plate 10 also rotates, and as a result, the movable element 9 can also move while maintaining a relationship facing the stator 6. Considering the case where the mover 9 rotates in the direction of arrow B from the reference position θ0, the opposing area between the mover 9 and the stator 6 decreases in inverse proportion to the angle.
Along with this, the capacitance also decreases in inverse proportion to the angle.

Therefore, by detecting the capacitance at a certain rotational position of the rotating shaft 8, the angle at the rotational position can be detected. This capacitance detection circuit will be briefly explained next time #C.

FIG. 3 is a block diagram of a detection circuit of a rotation angle detector according to an embodiment of the present invention. In the figure, numeral 10 is a capacitor formed by the movable element 9, stator 6, and rc of the rotation angle detector that oscillates. 14 is an AC/DC converter, 15 is a DC
The amplifier is a low pass filter.

Here, if the signal e of the oscillator lO of a predetermined frequency and a predetermined voltage is e, 8, and the capacitance of the capacitor 13 is Cx, Cx is first expressed as CI=Q, Q o s s s7x. Here, S is the facing area of the mover 9 and the stator 6, and X is the facing distance between the two shown in FIG. When this electric capacitance CI is amplified by the AC amplifier 5, the output e
, kaiku e, =-e, , *C,7cx =-e, 8・C7+1X10.0088S. That is, the current flowing through the capacitor 12 is reduced to ix% by the capacitor 13.
If the amount of current flowing through is e,=iZ=i,/ja+cz e,,=iZ=i,/jωcy i,=lid.

Therefore, e ,=i ,/ja+cX=e , , @j ωc
y/j ωcxwe,,cecY/Cx. However, the sign of the AC amplifier 12 (with inverted −t
″ru.

In this way, the output signal e of the AC amplifier 12 becomes a signal that is inversely proportional to the facing area S, and this signal is equal to the human C/DC'':
It is converted into direct current by an inverter 14, and then passed through a DC amplifier 15.
The signal is span-adjusted and amplified, shaped by a low-pass filter 16, and output as a rotation angle signal.

5c. In this embodiment, the stator is shaped as shown in FIG. 1, and the movable element that interlocks with the rotating shaft is placed opposite the stator, so the configuration is extremely simple and has a wide angle range (27
The angle of rotation can be measured over K (0 degrees). or,
Since the change in capacitance with respect to the change in angle is also linear, the measurement accuracy is also good.

In addition, in the explanation of the above embodiment, an example was explained in which a rectangular slider was made to move in conjunction with a rotating shaft, but in contrast to this, a half-wave mover is fixed as a stator, and the stator is rotated. It can also be used as a mover in conjunction with the shaft. In addition, although an example has been described in which the maximum width part and the minimum width part of the stator are in a range of 270 degrees, the range is not limited to 270 degrees.
An even larger angular range can be achieved as long as the movable element does not span both the maximum width portion and the minimum width portion.

Furthermore, it goes without saying that the reference position may be set to the minimum width portion instead of the maximum width portion. Also, the variation in the radial width of the stator 12 can be formed using the outer edge of the stator instead of the inner edge.

〔Effect of the invention〕

As described above, in the present invention, the first metal plate is arranged along the circumference, and the width of the first metal plate measured in the radial direction of the circle has a proportional relationship with the angle at the center of the circle. A second metal plate is formed so as to change continuously, and a second metal plate is disposed opposite a part of the first metal plate, and the first metal plate or t! @
2) Since the metal plate is made to move in conjunction with the rotating shaft, the rotation angle can be measured over a wide angular range with a simple configuration.

Further, since the change in capacitance with respect to the change in angle is linear, good measurement accuracy can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the stator and mover of the rotation angle detector according to the embodiment of the present invention, Fig. g2 is a side view of the rotation angle detector according to the embodiment of the present invention, and Fig. 3 A block diagram of a detection circuit of a rotation angle detector according to an embodiment, and FIGS. 4 and 5 are a side view and a front view, respectively, of a conventional rotation angle detector. 6... Stator, 7.10... Support plate,
8...Rotation axis, 9...Movement element.

Claims (1)

[Claims] a first metal plate disposed along the circumference of a circle and having a width measured in the radial direction of the circle that varies continuously in proportion to the angle of the center of the circle; a second metal plate provided opposite to the first metal plate; and the opposing positions of the first metal plate and the second metal plate are set so that the change in the width of the first metal plate appears. A rotation angle detector characterized by comprising a rotation axis that changes around a circle.