JPS62168004A - Detecting device for rotational angle position - Google Patents

Abstract

PURPOSE:To detect the angle of rotation of a body to be measured from the output of a magnetic detector by allowing one of a magnetic detector and a magnetic circuit structure to rotate for the other. CONSTITUTION:The magnetic circuit structure consists of couples of semicircular magnetic members 11 and 12 and permanent magnets 13 and 14 in a ring shape and is so fixed that it is unable to rotate. The permanent magnets 13 and 14 are sandwiched between both ends of the magnetic members 11 and 12 and arranged at both ends of the structure 10 in one diameter direction and have magnetic poles in the circumferential direction of the structure 10. The structure 10, on the other hand, forms a closed magnetic circuit. A magnetic detector 17 has a magnetic detecting element and is fixed atop of an arm 19 protruding from a shaft 18 and arranged inside the structure 10. Then, the shaft 18 rotates according to the rotation of the body to be measured and the magnetic detector 17 moves along the inner peripheral surface of the magnetic member 11 while detecting leak magnetic flux 10. Consequently, the absolute position of the angle of the rotating body to be measured is detected without contacting.

Description

[Detailed Description of the Invention] [Summary] Consists of an annular magnetic circuit structure that forms a closed magnetic circuit and a magnetic detector that detects leakage magnetic flux from the magnetic circuit structure. The magnetic circuit structure or the magnetic detector rotates in accordance with the rotation angle, and the absolute position of the rotation angle of the object to be measured can be detected from the output of the magnetic detector.

[Industrial application field]

The present invention relates to a rotational angular position detection device, and more particularly to a rotational angular position detection device using a magnetic detector.

[Conventional technology]

In general, devices that detect the rotation angle of the object to be measured include:
There is a rotary encoder that can determine the radial rotation angle by photoelectrically capturing the movement of moire edges using a radial grid provided around the entire circumference.

Further, a measuring device using a magnetic detector has a configuration in which a permanent magnet 1 and a magnetic detector 2 are arranged facing each other in free space, and one of them is moved in the opposite direction, as shown in FIG.

(Problems to be Solved by the Invention) According to the rotary encoder, it is possible to detect the rotation angle of the object to be measured, but it is not possible to detect the absolute angle, that is, the angular position, of the object to be measured relative to the reference position. It was impossible to detect.

Furthermore, according to the above measuring device, the magnetic detector 2 detects the strength of the magnetic field generated by the permanent magnet 1 and propagates in free space, and the opposing interval 2 can be determined. It was not possible to detect the moving angle position.

[Means for solving problems]

The rotation angular position detection device of the present invention includes a substantially annular magnetic circuit structure formed of a permanent magnet and a magnetic member to form a closed magnetic circuit, and a leakage of the magnetic circuit structure from the magnetic member. A magnetic detector detects magnetic flux, and one of the magnetic detector and the magnetic circuit structure is rotatable relative to the other.

[Effect]

The magnetic circuit structure generates leakage magnetic flux inside and outside of the structure that weakens as it moves away from the permanent magnet, and the magnetic detector generates leakage magnetic flux along the circumferential surface of the annular magnetic circuit structure in accordance with the rotation of the object to be measured. to detect leakage magnetic flux. It becomes possible to detect the absolute position of the rotation angle position of the object to be measured based on the output of the magnetic detector.

〔Example〕

1 and 2 are a perspective view and a plan view, respectively, schematically showing a rotation angle position detection device according to a first embodiment of the present invention.

In both figures, 10 is a magnetic circuit structure, which includes a pair of semicircular magnetic members (for example, iron plates) 11 and 12, and a permanent magnet 13.
．． 14, and is fixed in a non-rotatable manner. The permanent magnets 13 and 14 are sandwiched between both ends of the magnetic members 11 and 12, and are arranged at both upper ends of the annular magnetic circuit structure 10 in the negative diameter direction. Also permanent magnet 13.1
4 has a magnetic pole in the circumferential direction of the magnetic circuit structure 10, and the magnetic circuit structure 10 forms a closed magnetic circuit. Therefore, the second
As shown in the figure, the magnetic members 11.12 include permanent magnets 13.
A magnetic flux 15 passes from the N pole of the permanent magnet 14 toward the S pole, and a leakage magnetic flux 16 flows inside the magnetic circuit structure 10, which weakens as it moves away from the permanent magnets 13 and 14.

Both of the permanent magnets 13 and 14 are wedge-shaped and are arranged with their tops facing inward. This is because the leakage magnetic flux 16 is generated over the entire inner circumference of the magnetic circuit structure 10, thereby maximizing the angle detection range to 180 degrees.

Reference numeral 17 denotes a magnetic detector, which is configured to house a magnetic detection element that utilizes the magnetic resistance of a ferromagnetic metal (permalloy, etc.), and is fixed to the tip of an arm 19 extending from the shaft 18. The magnetic circuit structure 10 is located close to the inner peripheral surface of the magnetic circuit structure 11.
is placed inside. According to the rotation of the object to be measured, axis 1
8 rotates, and the magnetic detector 17 moves along the inner peripheral surface of the magnetic member 11 while detecting the leakage magnetic flux 16. Both the shaft 18 and the arm 19 are made of non-magnetic material.

FIG. 3 is a diagram showing the strength of the magnetic field due to the leakage magnetic flux 16 in the portion where the magnetic detector 17 moves.

In the figure, 0 degrees is the angular position indicated by P+ in FIG. P
1 is an intermediate position between the permanent magnets 13 and 14, and the leakage magnetic flux is zero. -90 degrees and 90 degrees are P2 and P3 respectively
The angular position corresponds to the top of the permanent magnet 13, 14 shown at . As shown by the curved line, the strength of the magnetic field is zero at 0 degrees, negative between 0 degrees and 190 degrees, and positive between 0 degrees and 90 degrees.

FIG. 4 is an output characteristic diagram of the leakage magnetic flux 16 detected by the magnetic detector 17 when the magnetic detector 17 moves between 22 and 23. The vertical axis is the output voltage of the magnetic detector 17, and the horizontal axis is the rotational angular position of the magnetic detector 17. Based on the relationship between the angular position and the output voltage represented by the curve (2), the angular position of the magnetic detector 17, that is, the absolute position of the rotation angle of the object to be measured, is detected from the output voltage.

FIG. 5 is a circuit diagram showing an example of the configuration of the measurement system of the magnetic detector 17 mounted on the device.

In FIG. 5, 21 is a magnetic sensing element circuit using permalloy magnetic resistance, 22 is a constant current source, 23 is an unbalanced voltage adjustment amplifier circuit, and 24 is a differential amplifier circuit.

By changing the voltage Vv applied to the input terminal 25 of the constant current source 22, the current 1 applied to the magnetic detection element 21 can be changed, and the current 1 is generated due to the unbalance of the bridge resistance of the magnetic detection element 21 regardless of the external magnetic field. The unbalanced voltage can be adjusted by a variable resistor R.

Then, the output of the magnetic detection element 21 is amplified, for example, about 100 times through the differential amplifier circuit 24, and measured and recorded by a digital multimeter, an X-Y recorder, etc. connected to the output terminal 26.

6 and 7 are a perspective view and a plan view, respectively, schematically showing a rotational angular position detection device according to a second embodiment of the present invention. In this embodiment, the detectable angle range is expanded to 360 degrees from 180 degrees in the first embodiment. In both figures, components that are substantially the same as those shown in FIGS. 1 and 2 are designated by the same reference numerals, and their explanations will be omitted.

In FIGS. 6 and 7, 30 is a magnetic circuit structure, which is composed of a substantially annular magnetic member 31 and a permanent magnet 32 provided between the ends of the magnetic member 31, and is fixed non-rotatably. be. The permanent magnet 32 has magnetic poles in the circumferential direction of the magnetic circuit structure 30, and the magnetic circuit structure 30 forms a closed magnetic circuit.

A magnetic flux 33 passes through the magnetic member 31, and the magnetic circuit structure 3
A leakage magnetic flux 34 that weakens as it moves away from the permanent magnet 32 flows inside the magnet 0. The permanent magnet 32 has a wedge shape and is arranged with the top facing inward so that the angle detection range can be expanded to the maximum of 360 degrees.

The shaft 18 rotates in accordance with the rotation of the object to be measured, and the magnetic detector 17 moves along the inner peripheral surface of the magnetic member 31 while detecting the leakage magnetic flux 34.

FIG. 8 is a diagram showing the strength of the magnetic field due to the leakage magnetic flux 34 in the portion where the magnetic detector 17 moves.

In the figure, 0 degrees is the angular position indicated by 01 in FIG. Q
1 is a position opposite to the permanent magnet 32 in the diametrical direction, and the leakage magnetic flux is zero. -90 degrees.

90 degrees are angular positions indicated by Q2 and Q3, respectively.

-180 degrees (180 degrees) is a position corresponding to the top of the permanent magnet 32 indicated by Q3. As shown by the curve ■ in FIG. 8, the strength of the magnetic field is zero at 0 degrees, negative between 0 degrees and -180 degrees, and positive between 0 degrees and +180 degrees.

FIG. 9 shows that the magnetic detector 17 is Q3→Q2→Q1→Q4→
When moving with Q3, the leakage magnetic flux 3 is detected by the magnetic detector 17.
FIG. 4 is an output characteristic diagram when 4 is detected.

The vertical axis is the output voltage of magnetic detector 17, and the horizontal axis is magnetic detector 1.
7 rotation angle position. Based on the relationship between the angular position and the output voltage represented by the curve (2), the angular position of the magnetic detector 17, that is, the absolute position of the rotation angle of the object to be measured, is detected from the output voltage.

10 and 11 are a perspective view and a plan view, respectively, schematically showing a rotational angular position detection device according to a third embodiment of the present invention. This embodiment is configured to detect angular positions within a range of 180 degrees by utilizing leakage magnetic flux to the outside of the magnetic circuit structure.

In both figures, the magnetic circuit structure 40 is substantially the same as the magnetic circuit structure 10 in FIGS. The horizontal permanent magnets 43 and 44 are arranged to form an rA magnetic circuit. 45 is the magnetic flux passing through the magnetic members 41 and 42;
46 is leakage magnetic flux leaked to the outside of the magnetic circuit structure 40. Similar to the leakage magnetic flux 16 described above, this leakage magnetic flux 46 becomes weaker as it moves away from the permanent magnets 43 and 44.

The magnetic detector 17 is close to the outer peripheral surface of the magnetic circuit structure 40, and detects leakage magnetic flux 46 as shown by the arrow in accordance with the rotation of the object to be measured. Moving. Based on the output from the magnetic detector 17, the absolute position of the rotation angle position of the magnetic detector 17 is detected within a detection range of 180 degrees.

12 and 13 are a perspective view and a plan view, respectively, schematically showing a rotational angular position detection device according to a fourth embodiment of the present invention. This embodiment is configured so that angular positions within a 360 degree range can be detected by utilizing leakage magnetic flux to the outside of the magnetic circuit structure.

In both figures, the magnetic circuit structure 50 is substantially the same as the magnetic circuit structure 20 in FIGS. 6 and 7, and includes a substantially annular magnetic member 51 and a top portion facing the inner circumferential side. The wedge-shaped permanent magnet 52 forms a closed magnetic circuit.

53 is a magnetic flux passing through the magnetic member 51, and 54 is a leakage magnetic flux leaking to the outside of the magnetic circuit structure 50. Similar to the leakage magnetic flux 34 described above, this leakage magnetic flux 54 becomes weaker as it moves away from the permanent magnet 52.

The magnetic detector 17 is close to the outer peripheral surface of the magnetic circuit structure 50, and detects the leakage magnetic flux 54 as shown by the arrow according to the rotation of the object to be measured. Moving. Based on the output from the magnetic detector 17, the absolute position of the rotational angular position of the magnetic detector 17 is detected within a 360 degree detection range.

In each of the above embodiments, the magnetic circuit structure 10, 30°, 40°.
50 is fixed, and the magnetic detector 17 rotates according to the rotation of the object to be measured; however, on the contrary, the magnetic detector 1
7 is fixed, the magnetic circuit structures 10.30, 40.50 are rotatably supported, and the magnetic circuit structures 10.30.40.
50 may be configured to rotate in accordance with the rotation of the object to be measured.

Also permanent magnets 13, 14, 32.43.44. .

Of course, 52 is not limited to the horizontal shape described above.

〔Effect of the invention〕

As described above, according to the present invention, the absolute angular position of a rotating object to be measured can be detected in a non-contact manner, and the structure can be simplified.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing a rotational angular position detection device according to a first embodiment of the present invention; FIG. 2 is a plan view showing the rotational angular position detection device together with leakage magnetic flux; The figure shows the strength of the magnetic field due to the leakage magnetic flux, Figure 4 shows the output characteristics of the rotation angle position detection device according to the first embodiment, and Figure 5 shows the measurement system of the rotation angle position detection device. 6 is a perspective view schematically showing a rotational angular position detection device according to a twelfth embodiment of the present invention, and FIG. 7 is a plan view showing the rotational angular position detection device together with leakage magnetic flux. , FIG. 8 is a diagram showing the strength of the magnetic field due to the leakage magnetic flux, FIG. 9 is an output characteristic diagram of the rotation angle position detection device according to the second embodiment, and FIG. 10 is a diagram showing the first embodiment of the present invention. FIG. 11 is a plan view showing the rotation angular position detection device together with leakage magnetic flux; FIG. 12 is a first embodiment of the present invention. FIG. 13 is a plan view showing the rotation angular position detection device together with leakage magnetic flux; FIG. 14 is a perspective view of a conventional potentiometer. . Figures 1, 2, 6, 7, 10 to 13
In the figure, 10.30, 40.50 are magnetic circuit structures, 11.12.31, 41.42.51 are magnetic members, 13.14, 32, 43.44.52 are permanent magnets, 15.33. 45, 53 are magnetic fluxes, 16, 34, 46, 54 are leakage magnetic fluxes, 17 is a magnetic detector, 18 is a shaft, and 19 is an arm. I-kou j [#口弐乗 (1 [gu1 bondto)] [fl Fig. 1 n Fig. 2 15 Output voltage - □ 〇 Textile warning □ Fig. 6 a7 Fig. Honkari drying 3 cusp Figure 11

Claims (6)

[Claims] (1) Permanent magnets (13, 14, 32, 43, 44, 52
) and magnetic members (11, 12, 31, 41, 42, 51)
a substantially annular magnetic circuit structure (10, 30, 40, 50) that forms a closed magnetic circuit; and the magnetic member (10, 30, 40, 50) of the magnetic circuit structure (10, 30, 40, 50). 11, 12, 31, 41, 42, 51), the magnetic detector (17) and the magnetic circuit structure. one of the bodies (10, 30, 40, 50) is rotatable relative to the other, and the magnetic detector (17)
A rotational angular position detection device, characterized in that the rotational angular position is detected from the detection output of the rotational angular position. (2) The magnetic detector (17) includes the magnetic circuit structure (
10, 30) The rotation angle position detection device according to claim 1, wherein the rotation angle position detection device is provided opposite to the inner periphery of the rotation angle position detection device 10, 30). (3) The magnetic detector (17) includes the magnetic circuit structure (
40, 50). The rotation angle position detection device according to claim 1, wherein the rotation angle position detection device is provided opposite to the outer periphery of the rotation angle position detection device 40, 50). (4) The magnetic circuit structure (30, 50) includes a substantially annular magnetic member (31, 51) and a single unit having magnetic poles in the circumferential direction and connected to the magnetic member (31, 51). permanent magnet (
32, 52). The rotational angular position detection device according to claim 1, characterized by comprising: (5) The magnetic circuit structure (10, 40) includes a pair of permanent magnets (13, 14, 43, 44) having magnetic poles in the circumferential direction and arranged at both ends in the diametrical direction, and A pair of semicircular magnetic members (11, 12, 41) are provided to sandwich the permanent magnets (13, 14, 43, 44) at
, 42). The rotation angle position detection device according to claim 1, characterized in that the rotation angle position detection device comprises: (6) The permanent magnet (13, 14, 32, 43, 44,
52) The rotational angle position detection device according to claim 4 or 5, wherein 52) has a wedge shape or a shape similar to this.