JPH061202B2 - Magnetic rotary encoder - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a magnetic rotary encoder configured by using a rotating disk made of a magnetic material.

[Outline of Invention]

The magnetic rotary encoder according to the present invention magnetizes the rotating disk using a magnetic head composed of an amorphous magnetic thin film which is arranged in a radial pattern at a predetermined pitch in the vicinity of the rotating disk made of a magnetic material, This is a rotary encoder that detects the Matthew voltage due to the Matteucci effect from the amorphous magnetic thin film to obtain the rotation angle of the rotating disk.

[Prior art and its problems]

In a conventional rotary encoder, a rotary disk in which a predetermined magnetic pattern is written in advance, or a rotary disk in which an optical pattern is formed is incorporated into a rotary encoder in both magnetic and optical systems. According to such a conventional rotary encoder, it is necessary to precisely align the rotating disk with the magnetic head or the fixed slit.
As the resolution of the rotating disk is improved, the centering of the rotating disk becomes difficult, and there is a problem that the phase difference of the output waveform of the rotary encoder may fluctuate even with a slight displacement of the rotating shaft.

On the other hand, a method of obtaining a pulse with high sensitivity by using a magnetic material with high magnetic permeability such as an amorphous thin film as a core of the magnetic head has been considered, but it is necessary to wind a coil wire around the core, so It was difficult to mount and configure the circuit.

[Object of the Invention]

The present invention has been made in view of the above problems of the conventional rotary encoder, and a rotary circle incorporated in the rotary encoder in order to prevent fluctuation of an output waveform due to eccentricity when the rotary disc is incorporated. An object is to provide a magnetic rotary encoder adapted to write a magnetic pattern on a plate.

[Constitution and effect of the invention]

The present invention is a magnetic rotary encoder for providing an output corresponding to a rotation angle of a rotary shaft, comprising a rotary disc which is held rotatably integrally with the rotary shaft and is made of a magnetic material, and a predetermined minute interval from the rotary disc. A magnetic head composed of an amorphous magnetic thin film formed in a series in a radial pattern on the insulating plate around the rotation axis at a predetermined pitch. It is characterized in that the rotating disk is magnetized over the entire circumference at predetermined intervals by the excitation of the thin film, and the rotation angle of the rotating disk is obtained based on the material voltage from the magnetic head.

According to the present invention having such characteristics, a rotary encoder is formed by using a rotating disk made of a non-magnetized magnetic material, and a magnetic pattern is written by using an amorphous thin film head for writing and reading. There is. Therefore, it is not necessary to perform centering when the rotary disk is assembled in the rotary encoder, and the assembly can be made extremely easy. When the rotary disk on which the magnetic pattern is written rotates in this way, a pulse-like Mateushi voltage can be obtained from the amorphous magnetic head. Therefore, by detecting the rotation angle based on this output voltage, the rotation angle of the rotating disk can be detected reliably. Therefore, according to the present invention, it is possible to realize a magnetic rotary encoder having a small phase jitter even at a small size of the rotating disk and an improved resolution at a relatively low cost.

[Explanation of Examples]

FIG. 1 is a schematic view showing the structure of a magnetic rotary encoder according to the present invention, FIG. 2 is a front view showing the magnetic head portion thereof, and FIG. 3 is a sectional view of the magnetic head. In these drawings, a magnetic rotary encoder 1 according to the present invention has a rotating disk 2 integrally attached to a rotating shaft 2 made of a magnetic material. Then, the magnetic head 4 is fixed on the circumference of the rotating disk 3 with a predetermined minute gap from the rotating disk 3. As shown in FIGS. 2 and 3, the magnetic head 4 has an insulating film 6 formed on a rectangular base 5 made of a non-magnetic material. As shown in FIG. 2, a large number of radial lines centering on the rotating shaft 2 are connected in series on the upper portion of the insulating film 6 to form a pattern in which the whole is formed in an arc shape. To be done. This pattern is formed by vapor-depositing an amorphous material having a high magnetic permeability on the insulating layer 6 to form the magnetic thin film 7, and the central portion of the fan shape is oriented toward the center of the rotating shaft 2. And this magnetic thin film 7
Terminals 8a and 8b are formed at both ends of the terminal as shown in FIG. Here, the pitch of the magnetic thin films 7 is configured to have a width of 1/2 of the magnetic pitch λ magnetized on the rotating disk 3, and the line width w of each magnetic thin film 7 is 1 / 4λ or less. Is configured as follows.

FIG. 4 is a diagram showing a configuration when the magnetic rotary encoder 1 configured as described above is magnetized. In this figure, a large-scale high-precision rotary encoder 12 is connected to a motor 11, and the rotary shaft 2 of the rotary encoder 1 described above is connected via a coupling 13 on the shaft thereof. The output of the large rotary encoder 12 is given to the frequency divider 14. The frequency divider 14 is a frequency divider that divides the output of the rotary encoder 12 in accordance with the resolution of the rotary encoder magnetized here, and supplies the frequency division output to the amplifier 15. The amplifier 15 amplifies the frequency-divided output by current and voltage, and its output is given to the terminals 8a and 8b of the magnetic head 4 described above.

When the motor 11 is rotated, the rotary shaft 2 of the rotary encoder 1 and the rotary disk 3 connected to the rotary shaft 1 are rotated at a predetermined speed through the coupling 13. At this time, the pulse obtained from the rotary encoder 12 according to the rotation angle is divided by the frequency divider 14, and the output is current / voltage amplified and given to the magnetic head 4.
Then, a predetermined current flows through the magnetic thin film 7 of the magnetic head 4 at predetermined intervals, and a magnetic pattern is written on the rotating disk 3. FIG. 5 is an enlarged view showing the state of magnetic flux when a current is applied to the amorphous magnetic thin film 7 of the magnetic head.
Since magnetic flux is formed along the magnetic thin film 7 of the magnetic head 4 as shown in this figure, radial N poles and S poles can be alternately formed on the rotating disk 3. Then, after rotating by a predetermined angle, the write current is supplied to the magnetic head 4 again by the output from the frequency divider 14. Then, one part is overwritten on the rotating disk 3 and the other part is written with a magnetic pattern on a new part of the rotating disk 3. By sequentially writing the magnetic patterns at predetermined angles in this manner, it becomes possible to continuously write the magnetic patterns on the predetermined circumference of the rotary disc 3 as shown in FIG.

A rotary encoder is completed by magnetizing the entire circumference of the rotating disk 3. When using this rotary encoder, the magnetic head 4 is used as a read head.
That is, when the rotating shaft 2 is rotated, the magnetic flux penetrating the amorphous magnetic thin film 7 of the magnetic head 4 is changed by the magnetic pattern on the rotating disk 3 as shown in FIG. Then, a pulse voltage that rises sharply when this magnetic flux is reversed, that is, a Mateshi voltage due to the so-called Mateshi effect is obtained. This signal is amplified by the number of radiation rays of the magnetic thin film 7 of the magnetic head 4, and a signal as shown in FIG. 7 is generated between the terminals 8a and 8b. Therefore, by shaping the waveform of this voltage signal, it is possible to obtain a pulse voltage corresponding to the rotation of the rotating disk 3.

In this way, a magnetic disk is written in advance after incorporating a non-magnetized rotating disk as a rotary encoder, and if the rotation angle is detected based on that pattern, there is no need for centering and it is an inexpensive and highly accurate magnetic type. It becomes possible to configure a rotary encoder.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a magnetic rotary encoder according to the present invention, FIG. 2 is a front view showing the magnetic head, FIG. 3 is a cross-sectional view thereof, and FIG. 4 is magnetic data in the magnetic rotary encoder. FIG. 5 is a configuration diagram showing the configuration when writing a magnetic pattern, FIG. 5 is a diagram showing a change in magnetic flux when writing a magnetic pattern, and FIG.
FIG. 7 is a diagram showing changes in magnetic flux of FIG. 7, and FIG. 7 is a diagram showing inter-terminal voltage obtained when the rotary encoder of this embodiment is rotated. 1 ... Magnetic rotary encoder 2 Rotating shaft 3 Rotating disk 4 Magnetic head 5
... Base 6 ... Insulating layer 7 ... Magnetic thin film 8a, 8b ... Terminal

Claims (1)

[Claims] 1. A magnetic rotary encoder for providing an output corresponding to a rotation angle of a rotating shaft, comprising: a rotating disk made of a magnetic material and rotatably held integrally with the rotating shaft; An insulating plate fixed at a predetermined minute interval, and a magnetic head formed of a series of amorphous magnetic thin films radially formed on the insulating plate around the rotation axis at a predetermined pitch, By magnetizing the amorphous magnetic thin film of the magnetic head, the rotating disk is magnetized over the entire circumference at predetermined intervals, and the rotation angle of the rotating disk is obtained based on the material voltage from the magnetic head. Characteristic magnetic rotary encoder.