JPH11166514A - Swing actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive swing actuator whose structure is simple and compact and which resistance to environment. SOLUTION: A swing actuator comprises a detecting head having a plurality of induction coils at prescribed positions of a static member and a rotor having a thin ferromagnetic rotary plate 8 opposed to the detecting head and externally fitted and fixed to a rotary shaft 9. The detecting head is formed by providing a primary induction coil 5 on the circumference of the static member outside the rotary plate 8 about the rotary shaft 9. A plurality of pins 4 are provided upright in parallel with the axis of the rotary shaft 9 in positions of the static member obtained by dividing the circumference inside the primary induction coil 5 at regular intervals. A first secondary induction coil 6 induced from the primary induction coil 5 and a second secondary induction coil 7 connected in series to the first secondary induction coil 6 with both polarities opposite to those of the first secondary induction coil 6 are respectively mounted on the pins 4. In the rotor, a cut-out non-inductive part is provided on the outer peripheral edge of the rotary plate 8, by which rotational displacement in the first induction coil 5 gives a sine change or cosine change to the outputs of the first secondary induction coil 6 and the second secondary induction coil 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swing actuator that swings to open and close a valve.

[0002]

2. Description of the Related Art FIGS. 9 and 10 show a conventional swing actuator. In FIG. 9, a potentiometer / rotary encoder 101 and the like are connected to a swing actuator 103 via a flexible joint 102 and the like.
In this case, the position is detected by fixing the potentiometer / rotary encoder 101 and the like to the swing actuator 103 with the bracket 105.

FIG. 10 shows a position transmitter 20.
1 and the like are connected to a rotation shaft 204 of a swing actuator 203 via a flexible joint 202, and a position transmitter 201 and the like are fixed to the swing actuator 203 by a bracket 205 to perform position detection.
In detecting only the positions at both ends, the limit switch is fixed by a bracket, and the kick metal of the limit switch is attached to the rotation shaft of the swing actuator.

[0004]

As described above, the conventional rotation sensor for a swing actuator has a complicated structure for coupling the sensor to the rotation shaft of the swing actuator and the sensor, and has a high cost and a compact size. Could not be structured. In addition, when the potentiometer or the rotary encoder is attached, it is necessary to store the potentiometer or the rotary encoder in a case in consideration of environmental resistance, in addition to the problem of an increase in external dimensions.

[0005]

In view of the above circumstances, the present invention simplifies the structure of a rotation sensor for a swing actuator, can provide it at low cost, has a compact structure, and has environmental resistance. In order to achieve this, a detection head in which a plurality of induction coils are arranged at predetermined positions on a stationary member, and a thin plate-shaped ferromagnetic rotating plate opposed to the detection head are externally fitted and fixed to a rotating shaft. The detection head is provided with a primary induction coil over the entire circumference of a stationary member outside a rotary plate about a rotation axis, the detection head being provided inside the primary induction coil. A plurality of pins are erected in parallel with the axis of the rotating shaft at positions of the stationary member equally dividing the circumferential direction at equal intervals, and a first secondary induction coil induced on the pins from the primary induction coil; With the first secondary induction coil A second secondary induction coil connected in series so that the side poles are opposite to each other is mounted, and the rotor has a rotational displacement within the primary induction coil of the first secondary induction coil and the second secondary induction coil. A swaying actuator is provided in which a sine and cosine change is given to the induction output and a cut-out non-inducing portion is provided on the outer peripheral edge of the rotating plate.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on embodiments shown in the accompanying drawings. First, FIG. 1 shows a sensor unit of the present invention having the simplest structure. The sensor section of the present invention includes a detection head 1 and a rotor 2. Detection head 1
In the stationary member 3, four metal pins 4, two each on the X and Y axes on the same radius, stand up parallel to the Z axis. Two flat coils are inserted into each pin 4 and mounted. Of these, the coil on the lower side (left side in the figure) of each pin 4 is a primary coil and the winding direction is all the same, and the four primary induction coils 5 are connected in series. On the other hand, the upper coil is a secondary coil, and two coils on the X-axis are first secondary induction coils 6.
The two on the Y axis are the second secondary induction coils 7. The two first secondary induction coils 6 and the two second secondary induction coils 7 are respectively connected in series, and the winding directions of the first secondary induction coil 6 and the second secondary induction coil 7 are reversed. And

On the other hand, the rotor 2 is formed by externally fitting a thin ferromagnetic metal rotating plate 8 on a rotating shaft 9. The rotating plate 8 is punched in a heart shape, and its rotating shaft 9 is rotatably fitted to the center holding hole 10 of the stationary member 3 so as to face the first and second secondary induction coils 6 and 7.
The heart-shaped groove is the cutout non-inducing portion 11. When an AC voltage of V = A sinωt is applied to the primary induction coil 5, a magnetic field is generated inside the coil, and a voltage is induced in the first and second secondary induction coils 6 and 7. Since the rotating plate 8 is formed in a heart shape and has the cut-out non-inducing portion 11, the magnitude of the induced voltage differs depending on the degree of overlap between the rotating plate 8 and the first and second induction coils 6.7. For example, as shown in FIG.
When attention is paid to the second secondary induction coil 7 on the axis, the heart of the rotating plate 8 hardly overlaps when the heart is upright.
Conversely, in the inverted state shown in FIG. 3, the rotating plate 8 almost completely overlaps with the secondary induction coil 7. When the rotating plate 8 makes one rotation, the induced voltage changes just like a sine wave. That is, if the rotational displacement of the rotating plate 8 is θ, Y
The induced voltage V ₁ of the second secondary induction coil 7 on the axis is as follows: V ₁ = A sin ωt · sin θ. The induced voltage V ₂ of the first secondary induction coil 6 on the X axis
Becomes V ₂ = A sin ωt · cos θ. These two signals, namely, the induced voltage V ₁ of the second secondary induction coil 7 and the induced voltage V ₁ of the first secondary induction coil 6
_In the conversion unit receiving the signal ₂ , the two are combined and the combined wave voltage V ₃
To one signal.

Since the carrier voltage V of the primary induction coil 5 and the composite wave voltage V ₃ have the same phase, the peak value A of the composite wave voltage
The phase difference θ is read from FIG. Therefore, shifting the phase of the carrier voltage V composite wave voltage V _3. That is, the composite wave voltage V ₃ becomes _{V 3 = a sin (ωt -θ} ). Detecting the rotational displacement θ from the phase difference between the carrier wave voltage V composite wave voltage V _3. It is shown in FIG.

FIG. 4 shows time t on the horizontal axis and voltage V on the vertical axis. The carrier wave voltage is represented by V, and is represented by a combined wave voltage V ₃ , and the peak value of the combined wave voltage V ₃ is represented by A.
Phase difference between the carrier wave voltage V composite wave voltage V ₃ detects the rotational displacement θ from the difference between the zero cross point. In the present embodiment, as shown in FIG. 5, the secondary induction coils are arranged in twelve equally on the circumference, so that the rotation angle 120 ° becomes one pitch. It is possible to get output. The number of secondary induction coils can be increased or decreased as necessary.

In FIG. 5, the circumference is divided into twelve equal parts,
Place the next induction coil. The rotation angle 120 ° is one pitch, and the first secondary induction coil 6 and the second
The secondary induction coil 7, the first secondary induction coil 6, and the second secondary induction coil 7 are inserted and mounted on the pins 4 that are erected in this order. In the three pitches, similarly to the above, the first secondary induction coil 6 and the second secondary induction coil 7 are respectively arranged in order. The primary induction coil 5 is arranged on the outer circumference of the first secondary induction coil 6 and the second secondary induction coil 7.

The rotating plate 8 is located on the left side of the Y-axis.
It almost completely overlaps the next induction coil 6 and then the next first 2
A cut is made so as not to overlap with the secondary induction coil 6 and so as to slightly overlap with the second secondary induction coil 7 on the left of each of the first secondary induction coil 6 and the next primary secondary induction coil 6. The non-inducing part 11 is provided. Thus, the rotating plate 8 becomes 1
If rotated by 20 °, the induced voltage changes just like a sine wave. That is, assuming that the rotational displacement of the rotating plate 8 is θ, the induced voltage V ₁ of the secondary induction coil 7 on the Y axis is V ₁ = A sin ωt · sin θ.

The induced voltage V ₂ of the first secondary induction coil 6 on the X axis is as follows: V ₂ = A sin ωt · cos θ These two signals, the second secondary induction coil 7
Induced voltage V ₂ of the induced voltages V ₁ and the first secondary induction coil 6
With the received conversion unit, converted into a signal that combines the two composite wave voltage V _3.

Since the carrier voltage V of the primary induction coil 5 and the composite wave voltage V ₃ have the same phase, the peak value A of the composite wave voltage
The phase θ is read from (see FIG. 4). Therefore, shifting the the transport voltage V composite wave voltage V ₃ phases. That composite wave voltage V ₃ becomes _{V 3 = a sin (ωt -θ} ). Detecting the rotational displacement θ from the phase difference between the carrier wave voltage V composite wave voltage V _3.

The example shown in FIG. 5 differs from the example showing the above principle in that the pitch is 120 degrees and one pitch is used.
FIGS. 6 to 8 show an example in which the above-described phase difference detection type rotation sensor is attached to a swinging actuator with an empty positioner. In the case where the empty positioner is not provided and the air positioner is directly mounted on the swing actuator, the same mounting is possible even if the empty positioner is replaced with an electropneumatic positioner.

FIGS. 6 and 7 show the swing actuator 11.
A positioner 12 is attached to an output shaft of the swing actuator 11, a rotation shaft of the positioner is connected to an output shaft of the swing actuator 11, and a detection unit 13 of a rotation sensor is provided at an end of the shaft.
Extend the cable 14 from the detection unit 13 of the rotation sensor,
A converter 15 for a rotation sensor is provided. Cable 1
4 may have a length of about 200 m.

FIG. 8 is an enlarged cross-sectional view of a part of the detection unit 13 of the rotation sensor of FIG.
The ring 21 is externally fitted to the rotating shaft 9 connected to the output shaft of the above, and is fixed to the rotating shaft 9 by screws 22. The rotating plate 8 externally fitted to the rotating shaft 9 is screwed to the ring 21 with screws 23. The primary induction coil 5 is fixed over the entire circumference of the inner peripheral surface of the housing 24 on the outer periphery of the rotating plate 8.

A pin 4 is erected at a position on the housing 24 which is divided into twelve equal parts on the circumference of the primary induction coil 5 in parallel with the axis of the rotating shaft 9. As described in detail, the first secondary induction coil 6 and the second secondary induction coil 7 are arranged as shown in FIG. Reference numeral 14 is connected to the conversion unit 15 of the rotation sensor by a cable. Operation is similar to that described above.

In the conventional oscillating actuator, the sensor is arranged outside the rotary shaft and the sensor cannot be arranged compactly. However, according to the present invention, the sensor detecting section is provided compactly at the shaft end of the rotary shaft. be able to.

[0019]

As described above, the present invention provides a detection head having a plurality of induction coils arranged at predetermined positions on a stationary member, and a thin plate-shaped ferromagnetic rotating plate opposed to the detection head. And a detection head comprising a primary induction coil having a primary induction coil extending over the entire circumference of a stationary member outside the rotary plate about the rotary axis. A plurality of pins are erected in parallel with the axis of the rotating shaft at a position of a stationary member that equally divides a circumferential direction inside the primary induction coil at equal intervals, and the pins are induced from the primary induction coil by the pins. A first secondary induction coil,
A secondary induction coil and a second secondary induction coil connected in series so that both poles are opposite poles are mounted, respectively, and the rotor has a rotational displacement within the primary induction coil of the first secondary induction coil and the second secondary induction coil. Since the sine and cosine changes are given to the induction output of the next induction coil, the oscillating actuator is provided with a cut-out non-inducing portion on the outer peripheral edge of the rotating plate. The structure of the rotation sensor for dynamic actuators is simplified, and the sensor has a simple structure, so the sensor can be provided at a low cost.The conversion part of the sensor can be installed separately from the detection part of the sensor.
In addition, the sensor can be arranged near the rotating shaft, so that the sensor has environmental resistance.

Further, in the conventional oscillating actuator, the sensor is arranged outside the rotation axis, and the sensor cannot be arranged compactly. However, according to the present invention, the detection unit of the sensor is compactly mounted on the end of the rotation axis. Can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating the principle of a rotation sensor according to the present invention.

FIG. 2 is a diagram illustrating a state in which a second secondary induction coil shown in FIG. 1 overlaps a rotating plate.

FIG. 3 is a front view illustrating a state in which a second secondary induction coil on FIG. 1 hardly overlaps with a rotating plate;

FIG. 4 is a graph illustrating a relationship between a carrier wave voltage and a composite wave voltage in FIG. 1;

FIG. 5 is a front view showing an outline of a sensor for explaining a specific example of the present invention.

FIG. 6 is a side view of a swing actuator with a positioner to which the present invention is applied.

FIG. 7 is a plan view of FIG. 6;

FIG. 8 is an enlarged side view of a part of FIG. 6;

FIG. 9 is a front view of a conventional swing actuator.

FIG. 10 is a front view of another conventional swing actuator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Head 2 ... Rotor 3 ... Stationary member 4 ... Pin 5 ... Primary induction coil 6 ... Primary secondary induction coil 7 ... Secondary induction coil 8 ... Rotating plate 9 ... Rotating shaft 10 ... Holding hole 11 ... Swing Actuator 12 Positioner 13 Rotation sensor detector 14 Cable 15 Rotation sensor connector 21 Ring 22 Screw 23 Screw 24 Housing

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Haruo Kashimoto 4-97, Uedahigashi-cho, Nishinomiya-shi, Hyogo Konan Electric Co., Ltd. (72) Inventor Masashi Mizutani 4-97, Uedahigashi-cho, Nishinomiya-shi, Hyogo Konan Electric Co., Ltd. (72) Inventor Kazuhiko Daimaru 4-97 Uedahigashi-cho, Nishinomiya-shi, Hyogo Konan Electric Co., Ltd.

Claims (1)

[Claims] 1. A detection head having a plurality of induction coils arranged at predetermined positions on a stationary member, and a thin plate-like ferromagnetic rotating plate opposed to the detection head fitted and fixed to a rotating shaft. And a detection head provided with a primary induction coil over the entire circumference of a stationary member outside the rotating plate about the rotation axis,
A plurality of pins are erected in parallel with the axis of the rotating shaft at a position of a stationary member equally dividing the circumferential direction inside the primary induction coil at equal intervals, and a second pin is induced on the pin from the primary induction coil. A primary secondary induction coil and a secondary secondary induction coil connected in series with the primary secondary induction coil and both poles being opposite poles are respectively mounted, and the rotor has a rotational displacement within the primary induction coil. An oscillating actuator provided with a cut-out non-inducing portion on an outer peripheral edge of a rotating plate, wherein sine and cosine changes are given to induction outputs of a first secondary induction coil and a second secondary induction coil.