JPH01148910A - magnetic rotary encoder - Google Patents

Abstract

PURPOSE:To detect the angle of rotation of a rotary shaft, by forming an asymmetric magnetic field by the magnetic member fixed to a rotary shaft and detecting the change of magnetic flux by a superconductive quantum interference element. CONSTITUTION:A magnetic member 12 is fixed to a rotary shaft 11 and constituted of a permanent magnet 12a and non-magnetic bodies 12b, 12c. Since the non-magnetic bodies 12b, 12d are fixed to the magnet 12a at positions asymmetric to the shaft 11, the magnetic field F formed by the member 12 is asymmetric with respect to the axis X-X of the magnet 12a. When the shaft 11 is rotated, the member 12 is also rotated and the ferromagnetic body 14 mounted on a fixing side 13 transmits the change of the magnetic flux F by the member 12 to a superconductive quantum interference element 15. Therefore, the angle of rotation of the shaft 11 is detected on the basis of the change of the magnetic flux detected by the element, and miniaturization and wt. reduction can be achieved.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a magnetic rotary encoder used, for example, to measure the rotation angle of a rotary joint of a robot.

[Conventional technology]

FIG. 5 is a perspective view showing the schematic configuration of a conventional magnetic rotary encoder, as shown, for example, on page 106 of the January 16, 1984 issue of Nikkei Mechanical. A drum fixed to the axle load, 3 a magnetic pole arranged on the circumference of the drum 2, 4 a magnetic sensor such as a magnetoresistive element or a Hall element that detects changes in the magnetic field due to the magnetic pole 3, 5 a magnetic sensor The wiring for deriving the output signal No. 4 is shown. Note that illustration of the circuit portion beyond the wiring 5 is omitted. Next, the operation will be explained. When the rotating shaft 1 rotates, the drum 2 fixed to the rotating shaft 1 also rotates, so that the magnetic field applied to the magnetic sensor 4 by the magnetic poles 3 on the circumference of the drum 2 changes. Therefore, by detecting changes in the magnetic field due to the magnetic poles 3 with the magnetic sensor 4, changes in magnetic flux due to changes in the magnetic field can be detected, and the rotation angle of the rotating shaft 1 can be detected by a circuit portion not shown.

[Problems to be solved by the invention]

Since the conventional magnetic rotary encoder is configured as described above, it is necessary to narrow the formation pinch of the magnetic poles 3 in order to improve the resolution. However, if the formation pinch of the magnetic pole 3 is narrowed, the magnetic field due to the magnetic pole 3 becomes weak (and changes in the magnetic field cannot be detected by the magnetic sensor 4. Therefore, when trying to obtain a high-resolution magnetic rotary encoder, it is difficult to There was a problem in that the diameter became larger and the device incorporating the magnetic rotary encoder became larger.This invention was made to solve the above problems, and it has high resolution and The purpose is to obtain a small and lightweight magnetic rotary encoder.

[Means for Solving the Problems] A magnetic rotary encoder according to the present invention includes a magnetic flux transmitting means that transmits a change in magnetic field as a change in magnetic flux caused by a magnet member that is fixed to a rotating shaft and forms an asymmetrical magnetic field; A superconducting quantum interference element connected to this magnetic flux transmission means is provided. Further, a magnetic rotary encoder according to another aspect of the present invention is provided at an asymmetric position with respect to the rotating shaft, where changes in the magnetic field due to a magnet member fixed to the rotating shaft and forming a symmetrical magnetic field are transmitted as changes in magnetic flux. This device includes two magnetic flux transmitting means, and a superconducting quantum interference element connected in correspondence with the two magnetic flux transmitting means. [Function] The magnetic rotary encoder according to the present invention supplies the output of the magnetic flux transmission means that transmits changes in the asymmetric magnetic field of the magnet member as changes in magnetic flux to the superconducting quantum interference element, thereby detecting the change in the asymmetric magnetic field with the superconducting quantum interference element. The rotation angle of the rotating shaft can be detected by changes in the magnetic flux. Further, in another aspect of the present invention, a magnetic rotary encoder supplies the outputs of two magnetic flux transmitting means for transmitting a change in the symmetrical magnetic field of a magnet member as a change in magnetic flux to two corresponding superconducting quantum interference elements. As a result, the rotation angle of the rotating shaft can be detected from the change in magnetic flux detected by the two superconducting quantum interference elements.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 11 indicates a rotating shaft, 12 indicates a magnet member fixed to the rotating shaft 11, and a permanent magnet (or electromagnet) 1
2a, and a permanent magnet 1 at an asymmetric position with respect to the rotation axis 11.
A diamagnetic material 12b, such as a superconductor, fixed to 2a.
, 12c, and forms a magnetic field F asymmetrical with respect to the axis XX of the permanent magnet 12a. 13 is a fixed side such as a casing, and 14 is a fixed side 1.
For example, a ferrite attached to 3. A ferromagnetic material such as cobalt nickel is used as a magnetic flux transmission means, and a change in the magnetic field caused by the magnet member 12 is transmitted as a change in magnetic flux. Reference numeral 15 indicates a superconducting quantum interference element connected to the ferromagnetic material 14, which has an ultra-high resolution that sensitively detects changes in magnetic flux of -1 millionth of the earth's magnetism. Reference numeral 16 denotes a magnetic shield, which shields the sensitive superconducting quantum interference element 15 from earth's magnetism and the like. Note that illustration of the circuit portion beyond the superconducting quantum interference element 15 is omitted. Since the superconducting quantum interference device 15 is well known, detailed explanation will be omitted. Next, the operation will be explained. When the rotating shaft 11 rotates, the magnet member 12 fixed to the rotating shaft 11 also rotates, so the ferromagnetic body 14 attached to the fixed side 13 converts the change in the magnetic field F caused by the magnet member 12 into a change in magnetic flux and converts it into a superconducting quantum interference element 15. Communicate to. Therefore, the rotation angle of the rotating shaft 11 can be detected based on the change in magnetic flux detected by the superconducting quantum interference element 15. As mentioned above, in the embodiment shown in FIG. Superconducting quantum interference device 15
The rotation angle of the rotating shaft 11 can be detected, and the size and weight can be reduced. Therefore, it is possible to downsize the device incorporating the magnetic rotary encoder. FIG. 2 is a schematic configuration diagram showing a magnetic rotary encoder according to another embodiment of the present invention. In the figure, the same parts as in FIG. This figure shows a permanent magnet (or electromagnet) as a magnet member, which forms a magnetic field FA symmetrical with respect to the axis YY of the permanent magnet 12A. 14A and 14B are ferromagnetic bodies attached to the stationary side 13 at 90 degrees to the rotation axis 11, 15A and 15B are superconducting quantum interference elements connected to the ferromagnetic bodies 14A and 14B, and 16A and 16B are magnetic bodies. Showing the shield. Fixed side 13 at an asymmetrical 90 degree position with respect to the rotation axis 11
14A ferromagnetic material attached to two places. 14B transmits a change in the magnetic field FA of the permanent magnet 12A, which changes with the rotation of the rotating shaft 11, to the superconducting quantum interference elements 15A and 15B as a change in magnetic flux. Therefore, the rotation angle of the rotating shaft 11 can be detected based on changes in the magnetic flux detected by the superconducting quantum interference elements 15A and 15B. As mentioned above, two sets of ferromagnetic materials 14A, 14B. Although the configuration is such that the rotation angle of the rotating shaft 11 is detected by the superconducting quantum interference elements 15A and 15B, the same effect as the embodiment shown in FIG. 1 can be obtained. FIG. 3 is a schematic configuration diagram showing a magnetic type rotary encoder according to still another embodiment of the present invention, and in the figure,
The same parts as in Figure 2 are given the same symbols, 17A,
17B is the fixed side 13 at a position of 90 degrees with respect to the rotating shaft 11.
It shows a fluff strasfer as a magnetic flux transmission means attached to a superconductor. The embodiment of FIG. 3 operates in the same manner as the embodiment of FIG. 2, and provides similar effects. FIG. 4 is a schematic configuration diagram showing a magnetic type rotary encoder according to still another embodiment of the present invention, and in the figure,
The same parts as in FIG. 2 are given the same reference numerals, and the ferromagnetic bodies 14A and 14B are attached to the asymmetric fixed side 13 at an angle different from 90 degrees to the rotating shaft 11. The embodiment of FIG. 4 operates in the same manner as the embodiment of FIG. 2' and provides similar effects. Note that the change in magnetic flux during one rotation of the rotating shaft 11 and the change in the magnetic flux during one rotation of the rotating shaft 11
The calibration of the correspondence with the position may be performed, for example, by using a large-diameter, high-resolution encoder as a mask. Then, information on the correspondence between this change in magnetic flux and the position of the rotating shaft 11 is stored, and by comparing it with the detected change in magnetic flux, the rotating shaft is adjusted.
1 position can be detected. Further, it is desirable that the magnetic flux transmitting means be disposed on the fixed side 13 so as to be asymmetrical with respect to the rotating shaft 11 within a range that does not adversely affect each other.

【Effect of the invention】

As described above, according to the present invention, there is provided a magnetic flux transmitting means for transmitting a change in magnetic field due to a magnetic member fixed to a rotating shaft and forming an asymmetrical or symmetrical magnetic field as a change in magnetic flux, and a magnetic flux transmitting means connected to the magnetic flux transmitting means. Since the present invention is equipped with a superconducting quantum interference device, the rotation angle of the rotating shaft can be detected by one or two sets of magnetic flux transmission means and superconducting quantum interference devices, and there is an advantage that the rotation angle of the rotating shaft can be detected, and the size and weight can be reduced. Therefore, it is possible to downsize the device incorporating the magnetic rotary encoder.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a magnetic rotary encoder according to one embodiment of the present invention, and FIGS. 2, 3, and 4 are schematic diagrams showing magnetic rotary encoders according to other embodiments of the present invention. , FIG. 5 is a perspective view showing a schematic configuration of a conventional magnetic rotary encoder. In the figure, 11 is a rotating shaft, 12 is a magnet member, 12A is a magnet member (permanent magnet), 13 is a fixed side, 14.14A and 14B are magnetic flux transmission means (ferromagnetic material), 15.15A
and 15B are superconducting quantum interference devices, 17A and 17
B is a magnetic flux transmission means (flux transfer), F, F
a indicates the magnetic field. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (6)

[Claims] (1) A rotating shaft, a magnet member fixed to the rotating shaft and forming an asymmetrical magnetic field, a magnetic flux transmitting means attached to the fixed side and transmitting changes in the magnetic field caused by the magnet member as changes in magnetic flux; A magnetic rotary encoder comprising a superconducting quantum interference element connected to a magnetic flux transmission means. (2) The magnetic rotary encoder according to claim 1, wherein the magnetic flux transmission means is a ferromagnetic material. (3) Claim 1, characterized in that the magnetic flux transmission means is a flux transfer made of a superconductor.
Magnetic rotary encoder described in section. (4) A rotating shaft, a magnet member that is fixed to the rotating shaft and forms a symmetrical magnetic field, and a magnet member that is attached at an asymmetric position with respect to the fixed rotating shaft, and that changes the magnetic field by the magnetic flux. two magnetic flux transmission means that transmit as a change;
A magnetic rotary encoder including two superconducting quantum interference elements connected in correspondence with these two magnetic flux transmission means. (5) The magnetic rotary encoder according to claim 4, wherein the magnetic flux transmission means is a ferromagnetic material. (6) Claim 4, characterized in that the magnetic flux transmission means is a flux transfer made of a superconductor.
Magnetic rotary encoder described in section.