JPH01244314A - rotary positioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] Configuration of a rotary positioner that includes a closed magnetic path structure in which a permanent magnet is provided in an annular magnetic member, and a magnetic sensor that detects a leakage magnetic field from the closed magnetic path structure. Regarding this, the magnetic member is characterized by having a shape in which the cross-sectional area continuously decreases as it moves away from the permanent magnet, with the aim of increasing and stabilizing the detection output of the magnetic sensor that detects leakage magnetic fields. Furthermore, the magnetic sensor is characterized in that the internal magnetization direction of the magnetic material pattern for magnetic detection is in the same direction as the leakage magnetic field within the detection angle range, and further characterized in that the rotating positioner is covered with a magnetic shielding member. and configure it.

[Industrial application field]

The present invention relates to a rotary positioner that detects the rotation angle of an object to be measured, and particularly to a leakage magnetic field type rotary positioner that utilizes the correspondence between a leakage magnetic field and a rotation angle.

[Conventional technology]

Figure 9 shows a leakage magnetic field type rotary positioner (patent application No. 6l-29258) filed by the present applicant on December 10, 1985.
FIG. 7) is a perspective view showing the main configuration of FIG.

In FIG. 9, the rotary positioner 1 includes a closed magnetic path structure 4 in which a permanent magnet 3 is provided in a part of an annular magnetic member 2, a magnetic sensor 5 that detects a leakage magnetic field from the magnetic member 2, and a circular plate. The arm 7 that supports the magnetic member 6 and the magnetic sensor 5 has a rotating shaft 8 projecting laterally, the magnetic member 6 and the rotating shaft 8 are coaxial with the central axis of the magnetic member 2, and the arm 7 that supports the magnetic sensor 5
is rotatable between the magnetic member 2 and the magnetic member 6 by the rotation of the rotating shaft 8 .

In such a rotary positioner 1, the magnetic sensor 5 detects a leakage magnetic field M generated inside the magnetic member 2, and the leakage magnetic field M becomes thicker as it approaches the permanent magnet 3.
Since the detection output also changes according to the rotation angle, the rotation angle of the rotating shaft 8 can be detected based on the detection output.

FIG. 10 is a diagram showing an example of the output characteristics of the rotary positioner 1. The position where the magnetic sensor 5 is farthest from the permanent magnet 3 (the position in the direction of arrow A in Fig. 9) is the origin of the rotation angle (0
In Fig. 10, the horizontal axis is the rotation angle (degrees) of the rotating shaft 8, and the vertical axis is the strength of the leakage magnetic field M (Oe; however, the measured value obtained from the output of the magnetic sensor 5). The output of the sensor 5 and the rotation angle of the rotating shaft 8 correspond one-to-one, and exhibit good linearity except in the vicinity of the permanent magnet 3.

[Problem to be solved by the invention]

The above-described conventional rotary positioner 1, which is applicable to a wide rotation range of ±150 degrees, is suitable for use with high accuracy in a narrow rotation range, such as ±60 degrees. Although using a strong permanent magnet 3 was insufficient, a magnetic material pattern having an internal magnetization Mi that was previously magnetized uniaxially was used to deal with the leakage magnetic field M which has directionality depending on the polarity of the permanent magnet 3. Magnetic sensor 5
In this case, it is desirable to limit the magnetization direction of the magnetic material pattern so that its output is maximized, and a configuration that is not easily influenced by external disturbance magnetic fields such as terrestrial magnetism is required.

In addition, in a leakage magnetic field type rotary positioner, the leakage magnetic field generated as position information of the magnetic sensor is about 40e8, and if there is a change in the leakage magnetic field due to an external magnetic field of 10e,
The output characteristics of the positioner fluctuate by about 2.5χ, and it is difficult to achieve the target accuracy of the rotary positioner of less than ±1%.

The present invention is a non-sliding, analog output rotary positioner for measuring rotation angles in FA control equipment, etc.
In particular, it improves detection ability and accuracy in a measurement range narrower than conventional methods, and stabilizes detection output.
The purpose is to achieve high performance.

[Means to solve the problem]

FIGS. 1(a) and 1(b) are plan views showing an example of the basic configuration of the present invention.

The rotary positioner 1) shown in FIG.
4 and a magnetic sensor 15 that detects a leakage magnetic field M from the closed magnetic path structure 14, and at least one of the closed magnetic path structure 14 or the magnetic sensor 15 rotates about the central axis C of the closed magnetic path structure 14. The magnetic member 12 has a configuration in which the rotation angle is detected based on the detection output of the magnetic sensor 15, and the cross-sectional area of the magnetic member 12 continuously decreases as it moves away from the permanent magnet 13 due to a change in the width W. It is characterized by

The rotary positioner 21 in FIG. 1(b) is a closed magnetic circuit structure 2 in which a permanent magnet 23 is provided in a part of an annular magnetic member 22.
4 and a magnetic sensor 25 that detects a leakage magnetic field M from the closed magnetic path structure 24, and at least one of the closed magnetic path structure 24 or the magnetic sensor 25 rotates about the central axis C of the closed magnetic path structure 24. The rotation angle is detected based on the detection output of the magnetic sensor 25, and the internal magnetization direction Mi of the magnetic material pattern for magnetic detection of the magnetic sensor 25 is in the same direction as the leakage magnetic field M within the detection angle range. The rotary positioner 1) and 21 are further characterized in that the outer peripheries of both the rotary positioners 1) and 21 are covered with a magnetic shielding member.

[Effect]

According to the above means, by reducing the cross-sectional area of the closed magnetic circuit structure in the direction away from the permanent magnet, the leakage magnetic field has linearity for applications in a limited angular range such as ±30 degrees or ±60 degrees. Since the increase occurs in this angle range without damage, it is possible to achieve higher precision measurement than before. When using a magnetic sensor that uses a magnetic pattern for magnetic detection, the internal magnetization direction of the magnetic pattern is By using this method, leakage magnetic fields can be detected efficiently, and measurement accuracy can be improved and stabilized.Furthermore, by covering the rotary positioner with a magnetic shielding member, the rotary positioner can be protected against external disturbance magnetic fields. Stabilize.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Rotary positioners according to embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a rotary positioner according to a first embodiment of the present invention shown in FIG. FIG. 2 is a perspective view showing the main configuration of a positioner.

In FIGS. 1(a) and 2, the annular magnetic member 12 partially provided with a permanent magnet 13 is arranged in a direction in which the center of the inner circle is separated from the permanent magnet 13 with respect to the center of the outer circle (arrow For example, the diameter of the outer circle is 30 mm, the diameter of the inner circle is 25 mm, and the deviation between the centers of the outer circle and the inner circle is 2 m. As a result, the cross-sectional area of the magnetic member 12 decreases continuously as it moves away from the permanent magnet 13, and the leakage magnetic field M in the area away from the permanent magnet 13 becomes smaller than that of the conventional magnetic member 2 as the cross-sectional area decreases. Become bigger.

Such a rotary positioner 1) has an L-shaped arm when, for example, the closed magnetic path structure 14 and the disc-shaped magnetic member 16 arranged concentrically with respect to the inner circle of the closed magnetic path structure 14 are fixed. A magnetic sensor 15 supported on a rotating shaft 8 via a magnetic sensor 7 and disposed between a magnetic member 12 and a magnetic member 16 detects a leakage magnetic field M that changes depending on its position, and detects a leakage magnetic field M based on the detection output. The rotation angle of the rotating shaft 8 can be detected.

FIG. 3 shows a rotary positioner according to a second embodiment of the present invention;
That is, they are a partially cutaway side view (a) and a perspective view (b) of a rotary positioner in which the cross-sectional area of an annular magnetic member provided with a permanent magnet is reduced by the second means.

In the rotary positioner 31 shown in FIG. 3, the magnetic member 32 of the closed magnetic circuit structure 34 has the permanent magnet 33 provided in a part of the annular magnetic member 32 in the direction away from the permanent magnet 33 (
The magnetic member 32 has an annular shape that becomes thinner continuously in the direction opposite to the arrow A), and as a result, the cross-sectional area of the magnetic member 32 continuously decreases as it moves away from the permanent magnet 33.
The leakage magnetic field M in a more distant region becomes larger than that of the conventional magnetic member 2 as the cross-sectional area decreases.

Such a rotary positioner 31 has an L-shaped arm 7 when, for example, a closed magnetic path structure 34 and a disk-shaped magnetic member 36 disposed concentrically with respect to the inner circle of the closed magnetic path structure 34 are fixed. The magnetic sensor 35, which is supported by the rotating shaft 8 via the magnetic member 32 and the magnetic member 36 and is disposed between the magnetic member 32 and the magnetic member 36, detects the leakage magnetic field M that changes depending on its position, and rotates based on the detected output. The rotation angle of the shaft 8 can be detected.

FIG. 4 is a diagram showing an example of the output characteristics of a rotary positioner in which the cross-sectional area of an annular magnetic member is continuously reduced.

Using the rotary positioner 1) shown in Figure 2, the permanent magnet 1
3, the position where the magnetic sensor 15 is farthest (position in the direction of arrow A in Fig. 1) is the origin of the rotation angle (0 degree), and the rotation angle (degrees) of the rotation shaft 8 is the horizontal axis, and the leakage magnetic field M The strength of (
In FIG. 4, where the vertical axis is Oe (measured value obtained from the output of the magnetic sensor 15), the output of the magnetic sensor 15 and the rotation angle of the rotation shaft 8 are in a one-to-one relationship at least within the rotation angle range of ±60 degrees. Corresponding to this, the strength of the leakage magnetic field exhibiting good linearity as shown by the solid line in the figure is approximately three degrees higher than the leakage magnetic field of the conventional rotary positioner 1 shown by the broken line in the figure. Further, such output characteristics are almost the same in the rotary positioner 31 as well.

FIG. 5 is a diagram for explaining changes in internal magnetization of a magnetic material pattern of a magnetic sensor, and FIG. 6 is a plan view showing a pattern shape of a barber pole type magnetoresistive element.

In FIG. 5, when the magnetic sensors 15 and 35 described above are sensors that utilize internally magnetized magnetic material patterns, for example, barber pole type magnetoresistive elements,
When the direction of internal magnetization Mi and the direction of leakage magnetic field M match (
As shown in a), the internal magnetization Mi does not change, but if the direction of the internal magnetization Mi and the direction of the leakage magnetic field M are opposite, (b)
), the internal magnetization Mi is demagnetized like Mi'.

In FIG. 6, the barber pole type magnetoresistive element is formed by forming an insulating layer made of SiO2 or the like on a substrate made of silicon or the like, forming a meandering magnetic material pattern 41 on the insulating layer, and then forming the magnetic material pattern 41 on the insulating layer. After imparting uniaxial magnetic anisotropy (internal magnetization) Mi in the longitudinal direction of 41,
Conductive films 42 made of Au or the like are formed diagonally at regular intervals.

In a magnetic sensor using such a resistive element, the angle θ formed by the direction of internal magnetization Mi of the magnetic material pattern 41 and the current i flowing through the conductive film 42 is π/4+nπ (or 7/4
If π-nyn (n=o, 1...=), the output can be increased.

Therefore, in the rotary positioner 21 of the third embodiment as shown in FIG. If the magnetic sensor 25 is installed in such a way that the direction of M coincides with the direction of the leakage magnetic field M, the output from the magnetic sensor 25 will be maximum and most stable in the two rotational directions.

FIG. 7 is a partially cutaway side view showing an example of the configuration of a rotary positioner that blocks external disturbance magnetic fields (external magnetic fields).

In FIG. 7(a), rotation positioner 1) (or 2
1.31) Cylindrical magnetic shielding member 51 covering the outer periphery of
is made of a magnetic material such as 6.5χ silicon steel, amorphous metal, or permalloy, and its height h is about 10 times larger than the thickness t of the rotary positioner 1), for example, a rotary positioner with an outer diameter of 30 mm. When the thickness dimension of 1) is t, h=10 is formed.

In FIG. 7(b), the rotary positioner 1) (or 2
1.31) The housing-shaped magnetic shielding member 52 that covers the
It is made of a magnetic material such as 6.5x silicon steel, amorphous metal, and permalloy, and protects the outer periphery, upper surface, and lower surface of the rotary positioner 1) from external disturbance magnetic fields.

In such magnetic shielding members 51 and 52,
When the magnetic permeability μ of the magnetic member 12 (or 22.32) of the rotary positioner is about 200, the magnetic shield member 5
1.52 uses a magnetic material with a magnetic permeability μ of 50,000 or more, and when the magnetic shield member 51.52 is fixed, its magnetic circuit becomes a dynamic magnetic field circuit, so the coercive force Hc is 0.0.
It is desirable to use a material with a diameter of 10e or less, and in order to prevent the magnetic shielding members 51.52 from affecting the leakage magnetic field M, the magnetic member 12 and the magnetic shielding members 51.52 must be separated by at least 41°.

FIG. 8 is a diagram for explaining the effect of the magnetic shielding member according to the present invention, where the horizontal axis is the disturbance magnetic field Hex (Oe), and the vertical axis is the measured value of the leakage magnetic field M at the set point in the rotary positioner (Oe). When a disturbance magnetic field Hex of 0 to 400e is applied, the rotary positioner equipped with the magnetic shield member 52 according to the present invention maintains a constant value of the leakage magnetic field M at a preset fixed point, while A rotary positioner that does not have the magnetic field measurement value will change under the influence of the disturbing magnetic field Hex.

〔Effect of the invention〕

As explained above, according to the present invention, by reducing the cross-sectional area of the closed magnetic circuit structure in the direction away from the permanent magnet, leakage can be reduced by reducing the cross-sectional area of the closed magnetic circuit structure in the direction away from the permanent magnet. The magnetic field increases over the angular range without loss of linearity, resulting in more accurate measurements than before.
When using a magnetic sensor that utilizes a magnetic material pattern for magnetic detection, the internal magnetization direction of the magnetic material pattern is set as in the above-mentioned means to efficiently detect leakage magnetic fields and improve and stabilize measurement accuracy. will be able to achieve this. Furthermore, by covering the rotary positioner with the magnetic shielding member, the rotary positioner is stabilized against external disturbance magnetic fields.

As a result, the detection accuracy of a non-sliding, analog output rotary positioner for measuring rotation angles in FA control equipment, etc. has been improved, the detection output has been stabilized, and high performance has been achieved.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a basic configuration example of the present invention, FIG. 2 is a rotary positioner according to a first embodiment of the present invention, FIG. 3 is a rotary positioner according to a second embodiment of the present invention, and FIG. The figure shows an example of the output characteristics of the rotary positioner according to the present invention, Figure 5 is an explanatory diagram of changes in the internal magnetization of the magnetic sensor, Figure 6 is the pattern shape of the barber pole magnetoresistive element, and Figure 7 is the magnetic shield member. FIG. 8 is an explanatory diagram of the effect of the magnetic shielding member, FIG. 9 is a conventional rotary positioner, and FIG. 10 is an example of the output characteristics of the conventional rotary positioner. In the figure: 1). 21.31 is a rotating positioner, 12, 22.32 are magnetic members, 13, 23.33 are permanent magnets, 14.24.34 are closed magnetic circuit structures, 15.25.35 are magnetic sensors, 51.52 are magnetic Indicates the shield member, C is the center of rotation, M is the leakage magnetic field, and Mi is the internal magnetization. <a> ^4 Hyohiaki's basic bridge construction 1) Display plane B No. 1
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Claims (3)

[Claims] (1) A permanent magnet (
13), and a magnetic sensor (15) that detects a leakage magnetic field (M) from the closed magnetic path structure (14), the closed magnetic path structure (14) or At least one of the magnetic sensors (15) is aligned with the central axis (C) of the closed magnetic path structure (14).
) around the rotation center, and the magnetic sensor (1
5) A rotary positioner that detects its rotation angle based on the detection output, characterized in that the magnetic member (12) has a shape whose cross-sectional area continuously decreases as it moves away from the permanent magnet (13). rotary positioner. (2) A permanent magnet (
23), and a magnetic sensor (25) for detecting a leakage magnetic field (M) from the closed magnetic path structure (24), the closed magnetic path structure (24) or At least one of the magnetic sensors (25) is aligned with the central axis (C) of the closed magnetic path structure (24).
) around the rotation center, and the magnetic sensor (2
5), in which the internal magnetization (Mi) direction of the magnetic material pattern for magnetic detection of the magnetic sensor (25) is within the detection angle range, the leakage magnetic field ( A rotary positioner characterized by being in the same direction as M). (3) A rotary positioner characterized in that at least the outer periphery of the rotary positioner according to claim 1 or 2 is covered with a magnetic shielding member (51, 52).