JPH0129521Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a differential transformer type angle detection device.

[Conventional technology]

(1) Background of the invention In general, a differential transformer is a device that converts a minute linear displacement signal into an alternating current voltage. This is the arrangement of possible movable cores M.

The center magnetic pole piece S of the E-type iron core _S is connected to an AC power source V.
An excitation winding N _S connected to is wound thereon, and output windings N _L1 and N _L2 are wound around the magnetic pole pieces S _L1 and S _L2 at both ends, respectively. Further, the output windings N _L1 and N _L2 are connected so that the polarities of the voltages generated by the same number of turns are opposite to each other. That is, the output windings N _L1 and N _L2 are differentially connected.

Therefore, when the excitation winding N _S is excited by the AC power supply V, the output winding
The number of magnetic fluxes interlinking with N _L1 and N _L2 changes, and voltages with mutually opposite phases are induced in each output winding N _L1 and N _L2 .

Based on this, the voltage difference between the respective voltages is output from the output terminal OUTPUT as a voltage proportional to the linear displacement position of the movable iron core M.

However, detecting the rotation angle via the linearly moving movable core M of this differential transformer is difficult.
This is not desirable for the following reasons.

First, since the air gap length between the output magnetic pole pieces S _L1 , S _L2 and the movable core M changes rapidly based on the linear motion (reference symbol L) of the movable core M, the magnetic resistance of the entire device is also continuous. There may be no change. For this reason, the range in which the output voltage characteristic changes linearly with respect to the rotation angle becomes extremely narrow, making it difficult to control the rotation angle.

Second, since a rotating body (not shown) is connected to the movable iron core M via a crank mechanism or the like, the mechanical load applied to the rotating body becomes heavy. For this reason, when detecting the angle of a rotating body such as a pen motor, which is designed to lighten the mechanical load as much as possible and increase recording accuracy, it is difficult to insert a movable iron core M that moves linearly. This will cause a decrease in accuracy.

Therefore, in order to detect an angle using a differential transformer, it is necessary to construct a direct angle detection device using a movable iron core that moves in rotation, rather than an indirect angle detection device using a movable iron core that moves linearly. Is required.

(2) Conventional Example A conventional differential transformer type angle detection device is as shown in FIG. FIG. 7A is a longitudinal sectional view thereof, and FIG. 7B is a perspective view thereof.

In the figure, reference numeral 3 denotes an E having an excitation magnetic pole piece 1 in the center and two output magnetic pole pieces 2 at both ends.
type iron core, a is an excitation winding wound around an excitation magnetic pole piece 1 and connected to an AC power source (not shown), and b is an excitation winding wound around an output magnetic pole piece 2 and differentially connected to each other (the first Figure 6) shows the output winding.

A rotating shaft 5 is disposed in parallel with and near the E-type iron core 3, and a rotating body whose rotation angle is to be detected, such as a rotor of a pen motor, is connected to the rotating shaft 5.

Further, on the outer surface of the rotating shaft 5, a cylindrical iron core 6 (a seventh
(B) is fixed and rotates in conjunction with the rotating shaft 5.

The portions at both ends of this rotating iron core 6 corresponding to both output magnetic pole pieces 2 are cut diagonally, forming beveled surfaces 6a and 6b having the same inclination.

In the conventional differential transformer type angle detection device having such a configuration, when the rotating iron core 6 rotates, there is no change in the air gap between the rotating iron core 6 and the excitation magnetic pole piece 1, but both outputs As for the gap between the iron core 2 and the iron core 2, as one gap gradually increases, the other gap gradually decreases.

Therefore, the magnetic resistance of the entire device also changes gradually,
Along with this, the number of magnetic fluxes interlinking with the output windings N _L1 and N _L2 also gradually changes.

Therefore, a characteristic of the output voltage U that changes linearly with respect to the rotation angle φ is obtained (FIG. 7C).

[The problem that the idea aims to solve]

The conventional differential transformer type angle detection device shown in Fig. 7 is designed to directly detect angles by providing a movable iron core that rotates, as described in (1) Background of the invention in [Prior technology]. That is.

However, in this prior art, since the oblique surfaces 6a, 6b are formed on the rotating iron core 6, the oblique surfaces 6a, 6b are formed on the rotating iron core 6.
There is a problem that the slope of the output voltage characteristic (FIG. 7c) changes depending on the slope angle of b, making the characteristic unstable.

As a result, even if angle control is attempted using this conventional technique, the following disadvantages occur.

For example, in the characteristic diagram of Figure 7C, the control system using this differential transformer type angle detection device
While the CPU stores characteristic C1 in advance,
It is assumed that the actual characteristic of the differential transformer type angle detection device is C3.

In this case, as is clear from the figure, the slope of the actual characteristic C3 is steeper than that of the characteristic C1 stored in the CPU, and the sensitivity is more sensitive. Therefore,
The CPU detects the first angle φ ₁ of the rotating body, and in an attempt to rotate it to the next second angle φ ₂ , the characteristic C1
Even if an attempt is made to control the rotor of the pen motor so as to obtain the variable voltage ΔV of the differential transformer calculated based on The rotor of the pen motor can only be rotated up to φ ₂ ′.

Furthermore, there is also the problem that it is extremely difficult to form the oblique surfaces 6a and 6b that always have a constant inclination angle on the rotating iron core 6 in terms of manufacturing.

An object of the present invention is to stabilize the output voltage characteristics of a differential transformer type angle detection device with respect to the rotation angle, and to obtain a rotating core that is easy to manufacture.

[Means to solve the problem]

The above problem consists of the excitation winding a in one excitation magnetic pole piece 1.
An E-shaped iron core 3 is provided, each of which is wound with an output winding b that is differentially connected to the two output magnetic pole pieces 2, and the excitation magnetic pole piece 1 and the output magnetic pole piece 2 are
A disc-shaped core 4 interlocked with a rotary shaft 5 coaxial with the excitation magnetic pole piece 1 is installed adjacently, and the excitation winding is attached to the bottom surface of the E-shaped core 3 of the disc-shaped core 4 regardless of its angular position. This problem is solved by a differential transformer type angle detection device characterized in that the region facing both the wire a and the output winding b is formed eccentrically with respect to the rotating shaft 5.

[Effect]

As described above, according to the present invention, the excitation winding a is wound around one excitation magnetic pole piece 1, and the output winding b, which is differentially connected to each other, is wound around two output magnetic pole pieces 2. In addition to providing the iron core 3, a disc-shaped iron core 4 that is interlocked with a rotating shaft 5 coaxial with the excitation magnetic pole piece 1 is attached adjacent to the excitation magnetic pole piece 1 and the output magnetic pole piece 2, and the E of the disc-shaped iron core 4 is attached. The area facing both the excitation winding a and the output winding b on the side bottom surface of the type iron core 3 regardless of the angular position is located on the rotating shaft 5.
It was formed eccentrically with respect to the

Therefore, the conventional cylindrical iron core 6 having the oblique surfaces 6a and 6b is no longer necessary, and elements that affect the slope of the output voltage characteristics, such as the inclination angle of the oblique surfaces 6a and 6b, are no longer present.

Therefore, it has become possible to stabilize the output voltage characteristics with respect to the rotation angle of the differential transformer type angle detection device.

Further, unlike the conventional cylindrical core 6 having oblique surfaces 6a, 6b, the disc-shaped core 4 has oblique surfaces 6a, 6b.
There are almost no difficult areas to process as shown in b.

Therefore, a movable iron core that is extremely easy to manufacture can be obtained.

〔Example〕

Hereinafter, the present invention will be explained by way of examples and with reference to the accompanying drawings.

FIG. 1 is a diagram showing a first embodiment of the present invention.

The reference numeral 3 shown in the figure is an E-type iron core having an excitation magnetic pole piece 1 in the center and two output magnetic pole pieces 2 at both ends, and a is an E-type iron core that is wound around the excitation magnetic pole piece 1 and connected to an AC power source (not shown). The excitation winding b is an output winding wound around the output pole piece 2 and differentially connected to each other (FIG. 6).

Opposing the excitation magnetic pole piece 1 and the output magnetic pole piece 2,
A rotating shaft 5 connected to a rotating body such as a rotor of a pen motor is provided coaxially with the excitation magnetic pole piece 1, and the rotating shaft 5 has a disc-shaped iron core 4 eccentric from the excitation magnetic pole piece 1.
is fixed, and there is a region on the bottom surface of the disk-shaped core 4 on the E-type core 3 side that faces both the excitation winding a and the output winding b, regardless of the angular position. Therefore, the disc-shaped iron core 4 is connected to the rotating shaft 5.
When interlocked with , its position with respect to the excitation winding a does not change, but its position with respect to the two output windings b at both ends gradually changes as shown by reference numerals 4' and 4'', even though they overlap. (Figure 1B).

FIG. 2 is a diagram showing a second embodiment of the present invention.

The difference from the first embodiment (FIG. 1) is that the disk-shaped core 4 is provided coaxially with the rotating shaft 5, and the excitation winding is connected to the bottom surface of the E-shaped core 3 of the disk core 4 regardless of the angular position. A circular recess 41 eccentric to the rotating shaft 5 is formed in a region facing both the output winding a and the output winding b.

Hereinafter, the operation of the present invention having the above configuration will be explained in the third section.
This will be explained based on the diagram.

The horizontal axis in FIG. 3A represents the rotation angle φ of the rotating body, which is the object to be detected, and hence the disc-shaped core 4, and the vertical axis represents the output terminal OUTPUT (6th
The output voltage U appearing in the figure) is shown respectively.

In the center diagram of FIG. 3B, the overlapping portions of the disc-shaped core 4 and the left and right output pole pieces of the E-shaped core 3 are the same, and part of the magnetic flux generated by the excitation winding a is generated by both output windings b. The numbers interlinked with are exactly the same.

On the other hand, since both output windings b are differentially connected to each other (Fig. 6), the output voltage is becomes 0.

With this zero point as a reference, when the disc-shaped core 4 rotates, at angles α and β where the overlapping portion with both output magnetic pole pieces 2 is largest, the magnetic flux interlinking with one of the output windings b is The number becomes maximum compared to 0 points, and maximum output voltages Uα and Uβ are obtained.

In this case, the movable iron core is replaced with the conventional oblique surfaces 6a, 6.
Unlike the cylindrical core 6, which is formed with a cylindrical core 6, the core 4 is configured as a disc-shaped core 4 (FIGS. 1 and 2). (Figure 7) The problem has disappeared and characteristic C (Figure 3) is always stable.

Moreover, unlike the conventional cylindrical core 6 formed with oblique surfaces 6a and 6b, the disk-shaped core 4 can be manufactured extremely easily.

FIG. 4 is a diagram showing an example of application of the present invention, in which an E-type iron core 3 and a disc-shaped iron core 4 are housed in a cylindrical housing 7.
is arranged, and the rotating shaft 5 fixed to the disc-shaped iron core 4 protrudes, and an AC power source connected to the excitation winding a and an output terminal connected to the output winding b are externally connected.
They are each arranged via lead wires.

FIG. 5 is a circuit diagram for carrying out the present invention, in which the rotating shaft 5 of the differential transformer type angle detection device according to the present invention is connected to the rotor of a pen motor, and the recording pen connected to the rotor is used to record an electrocardiogram. The purpose is to record waveforms such as the following on recording paper. The output voltage (FIG. 3) corresponding to the current angle of the recording pen is detected by the differential transformer type angle detection device and is inputted to the servo amplifier.

on the other hand. The main body of this control system, the CPU, is
Characteristic C of the differential transformer type angle detection device according to the present invention
(Fig. 3) is memorized in advance, and based on the information from the electrocardiograph, the corresponding output voltage is calculated based on the angle of the recording pen that should be reached for the next electrocardiogram to be drawn, and this is used as an input signal. Input to the above servo amplifier.

Therefore, a voltage corresponding to the difference between the current angle and the target angle is input to the pen motor, the recording pen reaches the target angle, and a predetermined electrocardiogram is drawn.

[Effect of idea]

As described above, according to the present invention, the excitation winding a is wound around one excitation magnetic pole piece 1, and the output winding b, which is differentially connected to two output magnetic pole pieces 2, is wound in an E type. In addition to providing the iron core 3, a disc-shaped iron core 4 that is interlocked with a rotating shaft 5 that is coaxial with the excitation magnetic pole piece 1 is installed in the vicinity of the excitation magnetic pole piece 1 and the output magnetic pole piece 2. Technical means of forming a region of the bottom surface of the side of the E-type core 3 that faces both the excitation winding a and the output winding b irrespective of the angular position so as to be eccentric with respect to the rotating shaft 5. was taken.

Therefore, the conventional cylindrical core 6 having the oblique surfaces 6a, 6b is no longer necessary, and there is no longer any element that influences the slope of the output voltage characteristics, such as the inclination angle of the oblique surfaces 6a, 6b.

Therefore, the technical effect of stabilizing the output voltage characteristics with respect to the rotation angle of the differential transformer type angle detection device has been achieved.

Further, unlike the conventional cylindrical core 6 having oblique surfaces 6a, 6b, the disc-shaped core 4 has oblique surfaces 6a, 6b.
There are almost no difficult areas to process as shown in b.

Therefore, a technical effect has been achieved in that a movable iron core that is extremely easy to manufacture can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a first embodiment of the invention, Fig. 2 is a diagram showing a second embodiment of the invention, Fig. 3 is an explanatory diagram of the operation of the invention, and Fig. 4 is an example of application of the invention. 5 is a circuit diagram for implementing the present invention, FIG. 6 is a general explanatory diagram of a differential transformer, and FIG. 7 is an explanatory diagram of a prior art. 1... Excitation magnetic pole piece, 2... Output magnetic pole piece, 3...
E-type core, 4...Disc-shaped core, 5...Rotating shaft, 4
1... Eccentric circular recess, a... Excitation winding, b... Output winding.

Claims (1)

[Claims for Utility Model Registration] (1) An excitation winding a is wound around one excitation magnetic pole piece 1, and an output winding b, which is differentially connected to two output magnetic pole pieces 2, is wound around an E. A type iron core 3 is provided, and a disc-shaped iron core 4 that is interlocked with a rotating shaft 5 coaxial with the excitation magnetic pole piece 1 is attached adjacent to the excitation magnetic pole piece 1 and output magnetic pole piece 2, and the disc-shaped iron core 4 A region of the side bottom surface of the E-type iron core 3 facing both the excitation winding a and the output winding b regardless of the angular position is formed eccentrically with respect to the rotating shaft 5. A differential transformer type angle detection device. (2) The differential transformer type angle detection device according to claim 1, in which the disc-shaped iron core 4 is mounted eccentrically with respect to the rotating shaft 5. (3) The disc-shaped iron core 4 is attached coaxially to the rotating shaft 5, and a circular recess 41 eccentric to the rotating shaft 5 is formed in the above region.Claim 1 The differential transformer type angle detection device described in .