JPS62180213A - Rotary differential transformer - Google Patents

Abstract

PURPOSE:To detect the angle of rotation of a transformer and to make the structure of the transformer simple and inexpensive by providing a rotary core and a primary coil which produce magnetic flux extending to the core and also providing a couple of secondary cores at the outer peripheral side of the core. CONSTITUTION:A since wave voltage for excitation is impressed from an oscillation circuit to the primary coil 5 and the primary coil 5 produces the magnetic flux. Then, this magnetic flux enters the center part of the rotary core 3 after passing through a rotating shaft 1, and reaches a magnetic pole member 6a and 6b and then the rotating shaft 1 by penetrating yokes 9 and 8. Consequently, a large voltage is induced across one secondary coil 7a and only a small voltage is induced across the other secondary coil 7b. The voltages induced across the secondary coils 7a and 7b are rectified by rectifying elements 11a and 11b of a detecting circuit 10 respectively and further smoothed by a capacitor, resistance, etc., to appear at output terminals 14a and 14b. Consequently, an output signal corresponding to the angle of rotation of the rotary core is obtained.

Description

[Detailed description of the invention] The present invention aims to solve the following problems.

(Industrial fjj field) This invention can be connected to the shaft of an industrial robot's bowl to detect the angular position (state) of its arm, or connected to the rotor of an AC servo motor to detect the rotor. This invention relates to a rotary differential transformer used to detect a rotation angle.

(Prior Art) There is a resolver as a device for performing the above-mentioned detection, but it has the problem of being 1.r expensive.

(Problems to be Solved by the Invention) This invention eliminates the above-mentioned conventional problems, and can detect rotation angles in the same way as the above-mentioned resolver, and can be provided with a simple structure and low cost. The present invention aims to provide a rotary differential transformer.

The configuration of the present invention is as follows.

(Means for Solving the Problems) The present invention takes the measures as described in the claims above, and its effects are as follows.

(Function) The magnetic flux generated by the primary cotton wrap is applied to the center of the rotating core. When the rotating core is connected to the detected member and rotates, its large diameter portion approaches one of the secondary windings or the other secondary winding. As a result, a signal can be obtained from each of the secondary windings according to the proximity state of the large diameter portion, that is, according to the rotation angle of the rotating core.

(Embodiments) The drawings showing the embodiments of the present application will be explained below. In Figures 1 to 4, 1 is a rotating shaft, and bearing 2
It is rotatably supported by

In this embodiment, this rotating shaft l also serves as a yoke for passing the magnetic flux generated by the primary winding, as will be described later.
The bearing 2 is made of a non-metallic material such as Permalloy, etc., and the bearing 2 is made of a non-metallic material. 3 is a rotating core, which has a circular planar shape, and is eccentrically connected to the rotating shaft. As a result, this rotating core 3 has a large diameter portion 3a with a large rotation radius Ra on one side, and a small diameter portion 3b with a small rotation radius Rb on the other side. Also, like the above-mentioned rotating shaft, this rotating core is made of a metal material with good magnetic properties such as permalloy.The outer shape of this rotating core 3 is determined according to the output waveform to be obtained as described below. It can be made into any shape depending on the shape.The shape may be, for example, a triangle (rice ball shape) with rounded corners or a square.5 is the primary winding;
This is for applying magnetic flux to the central portion of the rotating core 3.

5a and 6b indicate a pair of magnetic pole members disposed on the outer circumferential side of the rotary core 3 at equal distances from the rotation center of the rotary core 3, and their positions are different from each other (on the one hand, the large diameter portion 3
The small diameter portion is placed at a position where the small diameter portion faces the other when the portion a is opposed to the other portion. A pair of secondary windings 7a, 7b are individually wound around each outer periphery. 8.9
are disk-shaped and cylindrical yokes, respectively, which are provided to guide the flux (d) generated in the primary winding 5 together with the rotating shaft 1 as the yoke to the rotating core 3 and (magnetic pole members 6a, 6b). It is made of materials with good magnetic properties such as permalloy and silicon steel.10 indicates a detection circuit, which consists of a rectifying element 113.Ilb, smoothing capacitors 12a, 12b, and resistors 13a, 13b. It becomes.14 a, 14
b and 14c indicate output terminals, respectively.

The rotary differential transformer having the above configuration is used with the rotating shaft l connected to a well-known member to be detected (not shown) (robot arm shaft, AC servo motor rotor, etc.). In this state, a sinusoidal voltage for excitation is applied to the primary winding 5 from an oscillation circuit not shown. The frequency is, for example, I KH
It is about z~10KHz. By applying the above voltage, the primary winding 5 generates magnetic flux. The magnetic flux enters the center of the rotating core 3 through the rotating shaft 1 as shown by the broken line 15 in FIG. leading to. In such a state, a large amount of magnetic flux passes through the magnetic pole member, for example 6a, on the side of the rotating core 3 to which the large diameter portion 3 is close, and less magnetic flux passes through the magnetic pole member, for example 6b, on the side where the power factor diameter portion 3a is close. Only magnetic flux passes through it. As a result, a large voltage is excited in one secondary winding 7a, and the other secondary winding 7a is excited.
Only a small voltage is excited on line 7b. When the rotating core 3 rotates from this state and the distance between the magnetic pole member 6a and the rotating core 3 and the distance between the magnetic pole member 6b and the rotating core 3 become equal, the number of magnetic fluxes passing through the magnetic pole members 6a and 6b becomes equal. Therefore, each quadratic:? ! :The voltages generated on the lines 7a and 7b become equal. When the rotating core 3 further rotates and the large diameter part 3a approaches the magnetic pole member 6b and the small diameter part 3b approaches the magnetic pole member 6a, the secondary winding? The magnitude of the voltage excited at a and 7b is opposite to that in the case of 11η. As mentioned above, the voltage excited in each of the secondary windings 7a and 7b is rectified by the rectifying elements 11a and 11b in the detection circuit 10, and is smoothed by a capacitor, a resistor, etc., and then sent to the output terminal 1.
Appears in 4a and 14b. If we look at the voltages between these output terminals as output 1, output 2, and output 3 as shown in Figure 3, these outputs are analog outputs according to the rotation angle of the rotating shaft l as shown in Figure 4. Become. In addition, as shown in output 3, differentially extracting the output from the pair of secondary windings VA7a, 7b is done by reducing the temperature drift, etc., or by setting a zero cross point to increase the output. This is for stabilization.

Next, FIGS. 5 and 6 showing different embodiments of the present application will be described. This example is a set of two secondary volumes) 37ae
, 7be are arranged at 90 degrees with respect to the rotation center of the rotating core 3e. By arranging the above-mentioned secondary winding in such a positional relationship, the sixth
It is possible to obtain a waveform output as shown in the figure.

It should be noted that parts that are functionally the same or equivalent to those in the previous figure are given the same reference numerals as in the previous figure with an alpha character e, and redundant explanations are omitted.

(Also, the same idea will be used in the next and subsequent works, and the redundant explanation will be omitted by adding the letter f.) Next, Figures 7 and 8 are tree 1? In this example, 12 PJA magnetic pole members are arranged around the rotating core, and three pairs of secondary windings (7af, 7bf, 7a') are attached to these magnetic poles. f and 7b'f, 7a
"f and 7b") is shown as an example.

The positions of each set are shifted by 60 degrees, and each set has two sets of secondary: ? !
5. The lines are arranged so that they are 90 degrees apart from each other. With this configuration, outputs indicated by outputs 1 to 9 can be obtained at the output terminals of each detection circuit 10f with the phases shown in FIG. 8.

(Effects of the Invention) As described above, the present invention has the advantage that output signals corresponding to the rotation angle of the rotating core can be obtained from each pair of secondary windings.

Moreover, the structure is simple and can be provided at low cost.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and FIG. 1 is a longitudinal cross-sectional view;
Figure 2 is a horizontal sectional view, Figure 3 is a diagram showing the connection relationship between the secondary winding and the detection circuit, Figure 4 is an output waveform diagram, and Figure 5 is similar to Figure 3, showing a different embodiment. 6 is a diagram showing the output waveform in the circuit of FIG. 5, FIG. 7 is a diagram similar to FIG. 3 showing a further different embodiment, and FIG. 8 is a diagram showing the output waveform in the circuit of FIG. 7. figure. 3... Rotating core, 5... Primary winding, ? a. 7b...Secondary winding.

Claims (1)

[Claims] Consists of a freely rotatable rotating core, a primary winding that applies magnetic flux to the core, and a set of secondary windings arranged at different positions on the outer periphery of the rotating core. Rotary actuating transformer.