JPS63142201A - Apparatus for detecting angle of rotation - Google Patents

Abstract

PURPOSE:To detect an angle of rotation over 360 deg., by forming a continuity region due to the repulsive action of a magnetic field to a magnetoelectric converter element by a movable magnet to short-circuit conductors and detecting the angle of rotation thereof as a change in the resistance value between the conductors. CONSTITUTION:A membrane 25 of a magneto resistance element as a magnetoelectric converter element arranged between resistance wires 22 so as to fill the gap between said resistance wires 22 is formed by forming a membrane on a plate from InSb by a vacuum vapor deposition means. When this membrane is placed under a magnetic field, a non-continuity state is formed between the resistance wires and, when said membrane 25 is placed in a state partially near to a magnetic field free state, said part between the resistance wires becomes a continuity region E to short-circuit the resistance wires 22. Then, a movable magnet 28 is arranged to a rotary shaft 27 in a freely rotatable manner and, when the rotary shaft 27 is rotated in the directions shown by arrows A1, A2, a magnetic field G moves in the directions shown by arrows B1, B2. In parallel to this, the region E also moves in the same directions and the resistance wires 22 are short-circuited at that position to continuously detect the angle of rotation of the shaft 27 as the change in the resistance value between the resistance wires. Therefore, the angle of rotation in an entire region can be detected over almost 360 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotation angle detection device suitable for use in detecting the rotation angle of an arm, rotation shaft, etc. operated by automatic control, for example. The present invention relates to a non-contact rotation angle detection device that can improve detection performance.

[Prior art]

Generally, contact type and non-contact type rotation angle detection devices are known for detecting the rotation angle of a rotation axis or the like.

Therefore, FIG. 7 shows a contact type rotation angle detection device according to the prior art.

In the figure, 1 is a rotating shaft, 2 is a resistor arranged concentrically around the rotating shaft l, and terminals 2A, 2B are provided at both ends of the resistor 2, and the terminals 2A, 2B are provided at both ends of the resistor 2. 2B is connected to a power source (not shown) or the like. Reference numeral 3 indicates a brush that is rotatably provided on the rotating shaft 1, and the brush 3 contacts the resistor 2 and slides on the resistor 2, for example in the direction of arrow A. . Reference numeral 4 indicates a lead wire connected to the brush 3, and another terminal 4A is provided at the tip of the lead wire 4.

Thus, in the contact-type rotation angle detection device having the above-described configuration, since the brush 3 that rotates integrally with the rotating shaft l slides on the resistor 2, the brush 3 connects the terminals 2A and 2B.
For example, terminals 4A and 4A are short-circuited, and the rotation angle of rotation axis
It can be detected as a change in resistance value between 2A.

Next, FIG. 8 shows a non-contact type rotation angle detection device according to the prior art.

In the figure, 11 is a rotating shaft, 12 is a magnetoelectric transducer arranged around the rotating shaft 11, and the resistance value of the magnetoelectric transducer 12 increases when placed under a magnetic field. There are terminals 12A on both ends.

12B is provided. Further, reference numeral 13 indicates a magnet that is rotatably provided on the rotating shaft 11, and the magnet 13 is formed, for example, in the shape of a semicircular plate, and is rotated by the rotating shaft 11 in the direction of arrow A. There is. 14
indicates a lead wire whose one end side is connected to the middle of the magnetoelectric conversion element 12, and the other end side of the lead wire 14 is connected to another terminal 14A.
is provided.

Thus, in the non-contact rotation angle detection device having the above-described configuration, when the magnet 13 is rotated by the rotation shaft 11, the magnetoelectric conversion element 12 is configured such that the portion overlapping with the magnet 13 is placed under the magnetic field. Therefore, the resistance value of this portion increases, and the rotation angle of the rotating shaft 11 can be detected as a change in the resistance value between the terminals 14A and 12A, for example, as shown in FIG. 9.

[Problem that the invention seeks to solve]

However, each of the above-mentioned conventional techniques has the following drawbacks.

First, in the contact type, the brush 3 slides on the resistor 2, so
Not only does the rotational torque of the rotating shaft 1 increase, but the brush 3 and the resistor 2 gradually wear out, shortening their lifespan.

Further, it has the disadvantage that it generates sliding noise, sliding arc, etc., and lacks explosion-proof properties.

On the other hand, with the non-contact type, although the disadvantages of the contact type can be overcome, the magnet 13 allows the magnetoelectric conversion element 1 to
2 is simply placed under a magnetic field and the resistance value is increased or decreased, so as shown in Figure 9, the detectable rotation angle is limited to less than 180 degrees, in fact it is limited to about 120 degrees, and it is impossible to detect more than that. The disadvantage is that the rotation angle cannot be detected.

The present invention has been made in view of the above-mentioned drawbacks of the prior art.The present invention is capable of detecting rotation angles over almost the entire range up to about 360 degrees, and is capable of improving performance and simplifying the structure. The present invention provides a non-contact rotation angle detection device.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention has two conductive wires arranged at a predetermined distance apart, at least one of which is a resistance wire, and a conductive wire arranged between the six conductive wires so as to fill the space between the six conductive wires. a strip-shaped magnetoelectric transducer, a strip-shaped magnet disposed so as to overlap one surface of the magnetoelectric transducer in order to place the magnetoelectric transducer under a magnetic field, and a strip magnet arranged to overlap on one surface of the magnetoelectric transducer, and a strip magnet spaced apart from the other surface of the magnetoelectric transducer. a rotating member provided on the rotating member; and a movable magnet provided on the rotating member and having the same polarity as the strip magnet on the side facing the strip magnet, and the movable magnet causes a repulsive magnetic field to act on the magnetoelectric conversion element. A configuration is adopted in which a conductive region is formed to short-circuit the conductive wires, and the rotation angle of the movable magnet is detected as a change in the resistance value between the conductive wires.

[Effect]

Although the magnetoelectric transducer placed under a magnetic field by the strip magnet has a large resistance value and creates non-conductivity between the conductors, the part of the magnetoelectric transducer that the movable magnet faces is free of magnetic field or no magnetic field due to the repulsion of the magnetic field. In this state, the resistance value decreases significantly and a conductive region is formed that short-circuits the conductive wires. Then, as the movable magnet rotates, the conduction region of the magnetoelectric transducer also moves, and the resistance value between the conductive wires changes.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 6.

1 to 4 show a first embodiment of the invention.

In the figure, 21 indicates a plate serving as a substrate, and the plate 21 may be made of plastic, reinforced plastic, glass,
It is made of a non-magnetic material such as ceramic or stainless steel and is formed into a rectangular plate shape as shown in FIG. The plate 21 is fixed to a casing (not shown) and positioned slightly upward from a rotating shaft 27, which will be described later. Reference numerals 22 and 22 denote resistance wires as conducting wires that are arranged to extend in parallel on both sides of the plate 21 at a predetermined distance apart.

For example, it is formed by forming a thin film of a NiCr-based resistor on the film 21 using means such as vacuum evaporation, sputtering, or ion blating, and is connected to both sides of the Q film 25, which will be described later. (Second
), and lead wires 23 and 23 are connected to one end of each resistor kQ22, respectively, and terminals 24A and 24B for connection to a power source etc. are provided at the tip side of each lead wire 23. .

Reference numeral 25 indicates a thin film of a magnetoresistive element as a magnetoelectric conversion element disposed between each resistance wire 22 so as to fill the space between the resistance wires 22, and the thin film 25 is made of In5, which is the material of the magnetoresistive element.
It is formed into a band shape by forming a thin film of indium antimony b (indium antimony) or the like on the plate 21 using means such as vacuum evaporation or sputtering. That is, the thin FI 25 is formed by forming an i-film on the plate 21 so as to fill the spaces between the resistance wires 22 after the resistance wires 22 are arranged on both sides of the plate 21 in advance. The thickness of 22 is approximately several gm. Here, when the thin film 25 is placed under a magnetic field, its resistance value becomes multiplied by a factor of 1 as a magnetoresistive element, and the resistance wires 22 become non-conducting, resulting in a partially non-magnetic field or nearly non-magnetic field state. When placed, the resistance value decreases, and this part becomes a conductive region E, and each resistance wire 22
(Fig. 2).

(See Figure 3).

Reference numeral 26 indicates a strip-shaped magnet disposed so as to overlap the upper surface side of the thin film 25 in order to place the FIM 25 of the magnetoresistive element under a predetermined magnetic field. 25, and the thin RF! It is designed to be stacked on top of J25. Then, the belt-shaped magnet 2
As shown in FIG. 3, the lower surface of the sun serves as, for example, the north pole and causes lines of magnetic force F1 to run downward.

Although the belt-shaped magnet 26, plate 21, thin W 125, etc. are shown separately in FIGS. 1 to 3 for convenience of explanation, they are mutually layered.

Next, reference numeral 27 indicates a rotating shaft as a rotating member extending parallel to the plate 21 with a slight distance from the lower surface of the plate 21, and the rotating shaft 27 is rotated by the casing via a bearing or the like. It is supported so that it can rotate in the direction of arrow Al*A2 around the central axis 0-0. The outer peripheral surface of the rotating shaft 27 located around a movable magnet 28 (described later) or the entirety thereof is formed of a non-magnetic material, so that it can be prevented from being magnetized by the movable magnet 28.

Further, reference numeral 28 denotes a tape-shaped movable magnet that is spirally arranged with a predetermined lead angle on the outer peripheral surface of the rotating shaft 27. The rotating shaft 27 is formed by vapor deposition so as to extend spirally on the outer peripheral surface of the rotating shaft 27, and has a spiral length corresponding to one pitch of a screw, etc.
It is arranged on the outer peripheral surface of. As the movable magnet 28 rotates in the directions of arrows Al and A2 of the rotating shaft 27, any part along the spiral (the uppermost part in FIG. 2) is exposed to the magnetic field of the strip magnet 26. Opposing magnetic field G
is formed as shown in FIG. 2, and the magnetic field G is
0 along arrow Bl.

It is adapted to move in the B2 direction based on the spiral of the movable magnet 28.

Here, the movable magnet 28 has a north pole on its surface side and runs magnetic lines of force F2 upward along the magnetic field G (see Fig. 3), and the magnetic force &1F2 partially deflects the magnetic lines of force Fl of the strip magnet 26. By causing repulsion, for example, this portion is placed in a state without a magnetic field or in a state close to a non-magnetic field. As a result, a conductive region E where the resistance value is small is formed in the portion of the thin film 25 that faces the magnetic field G of the movable magnet 28, and the resistance wires 22 are short-circuited via the conductive region E. When the movable magnet 28 is rotated together with the rotating shaft 27 in the direction of the arrows Al and A2, the magnetic field G of the movable magnet 28 moves in the direction of the arrows B1 and B2 based on the spiral. The conduction area E similarly moves in the direction of arrow BIIB2, and each resistance line 2
The resistance value between the two changes as illustrated in FIG. 6 in response to the rotation angle of the rotating shaft 27.

The rotation angle detection device according to the present embodiment has the above-described configuration, and since the movable magnet 28 is spirally disposed on the outer peripheral surface side of the rotating shaft 27, the movable magnet 28 faces the magnetic field of the strip magnet 26. The magnetic field G of 28 is the rotation axis 2
According to the rotation in the direction of arrows Al and A2 of 7, arrows Bl and B2
move in the direction. Then, in the thin film 25 of the magnetoresistive element placed under the magnetic field of the strip magnet 26, due to the repulsion of the magnetic field by the movable magnet 28, a conductive region E is formed at the portion facing the magnetic field G of the movable magnet 28,
Each resistor &! 22 are short-circuited, and the same effect as the conductive short-circuit body 29 shown in FIG. 4 can be obtained. That is, the shorting body 29 slides between each resistance wire 22 in two directions indicated by the arrow B I + B, short-circuits each resistance wire 22 at the displacement position, and reduces the resistance between each resistance wire 22. It is designed to change the value.

Thus, according to this embodiment, if the movable magnet 28 is rotated together with the rotating shaft 27 in the directions of the arrows Al and A2, and the magnetic field G of the movable magnet 28 is moved in the directions of the arrows B1 and B2, Accordingly, the conductive region E of the thin film 825 also moves in the same direction, and at that moving position, the resistance wires 22 can be short-circuited, and the rotation angle of the rotating shaft 27 can be continuously changed as the resistance value between the resistance wires 22 changes. It is possible to detect rotation angles over a full range of almost 360 degrees. Then, each resistance wire 22 is lengthened, and the movable magnet 2
If the helical length of No. 8 is increased by increasing the lead angle, even small rotation angles can be detected, and the detection performance can be reliably improved.

Also, the plate 21, each resistance wire 22. The thin film 25, the strip magnet 26, etc. extend in the axial direction of the rotating shaft 27,
Since they are mutually planted, the radial dimension of the detector can be reliably reduced, the overall structure can be simplified and compactly formed, and each resistor can be There is no need to slide between the wires 22, and it is possible to prevent sliding noise and arcing, and it is possible to improve lifespan, reduce rotational torque, etc.

Furthermore, since the thin film 25 of the magnetoresistive element is laminated between the plate 21 and the strip magnet 26, the thin film 25 can be protected from the outside, and detection errors etc. can be prevented from occurring due to changes in the external environment. It has various effects, such as being able to prevent.

Next, FIG. 5 and FIG. 6 show a second embodiment of the present invention, and the feature of this embodiment is that the main body casing of the rotation angle detection device is formed of a cylindrical inner cylinder and an outer cylinder. A thin film of a magnetoresistive element, a band-shaped magnet, etc. are built in between, and a rotary shaft is rotatably disposed inside the inner cylinder.

In the figure, 31 indicates the main body casing of the rotation angle detection device,
The casing 31 has an inner cylinder 31 formed into a cylindrical shape and made of the same material as the plate 21 described in the first embodiment.
A and an outer cylinder 31B disposed on the outer circumferential side of the inner cylinder 31A so as to sandwich a thin film 33, a band-shaped magnet 34, etc., which will be described later, between the inner cylinder 31A. It may be formed of the same material as the inner cylinder 31A, or a fiber material impregnated with resin may be wound around the outer circumference of the inner cylinder 31A using a method such as a filament winding method, a tape winding method, or a hand lay-up method. Note that for convenience of explanation, a gap is shown between the inner cylinder 31A and the outer cylinder 31B in FIG. 5, but this gap does not actually exist. . Moreover, the outer cylinder 31B is used as a cover, and the belt-shaped magnet 3
It may be formed so as to cover only the periphery of the 4th grade.

Reference numerals 32 and 32 indicate a resistance wire as a conducting wire, and 33 indicates a thin film of a magnetoresistive element, and each resistance wire 32 and thin film 33 are formed almost in the same manner as each resistance wire 22 and thin film 25 described in the first embodiment. It is disposed extending in the axial direction on the outer circumferential surface of the inner cylinder 31A.

In addition, 34 is a thin 11! of a magnetoresistive element! A strip magnet stacked on the upper surface side of J33 is shown, and the strip magnet 3
4 is formed of a plastic magnet or a magnetic thin film, etc., substantially similar to the strip magnet 26 described in the first embodiment, and is adapted to place the thin film 33 of the magnetoresistive element under a predetermined magnetic field.

In addition, when the strip magnet 34 is formed of a magnetic thin film, a film such as carbon is coated on the thin film 33 of the magnetoresistive element in advance.
After depositing a non-magnetic thin film such as r + Cu + Sr + Sl 02, for example Fe is deposited on top of this.
A magnetic thin film of N+, B12O3, N+-Cr, etc. may be deposited. Moreover, the belt-shaped magnet 34
and Thin 11133 etc. are laminated on the outer peripheral surface of the inner cylinder 31A in place of the plate 21 described in the first embodiment, and are curved and formed along the outer peripheral surface of the inner cylinder 31A. . The belt-shaped magnet 34 is completely covered and protected by the outer cylinder 31B.

Next, 35 is a rotating shaft as a rotating member that is rotatably disposed at a slight distance inside the inner cylinder 31A, and 36 is a movable magnet that is spirally disposed on the outer peripheral surface side of the rotating shaft 35. The movable magnet 36 and rotating shaft 35 are formed in the same manner as the movable magnet 28 and rotating shaft 27 shown in FIG. 2 described above. Also, in the movable magnet 36, the magnetic field facing the strip magnet 34 moves in the axial direction due to the rotation of the rotating shaft 35, and accordingly, the conductive region formed in the thin film 33 also moves in the same direction, and each resistance wire 32 The resistance value between the two changes as shown in FIG. 6 in accordance with the rotation angle of the rotating shaft 35.

Thus, even in this embodiment configured in this way, the first
Although it is possible to obtain almost the same effects as in the embodiment,
In particular, in this embodiment, the thin film 33 of the magnetoresistive element, each resistance wire 32, the strip magnet 34, etc. are attached to the main body casing 3.
Since the detection device is embedded between the inner cylinder 31A and the outer cylinder 31B of 1, it is possible to incorporate the detection device made of the thin rFJ 33, the band-shaped magnet 34, etc. into the main body casing 31 surrounding the rotating shaft 35. This makes it possible to make the whole structure even more compact.

Moreover, the thin film 33 can be protected more reliably, and detection errors caused by changes in the external environment can be more reliably prevented.

In each of the above embodiments, two resistance wires 22 (32) are used, but either one of the resistance wires 22 (32) may be formed of a conductive wire with high conductivity. .

Furthermore, in each of the above embodiments, the movable magnet 28 (36)
Although it has been described that the movable magnet 28 is arranged spirally on the outer peripheral surface side of the rotating shaft 27 (35), instead of this, the movable magnet 28
(36) is extended linearly in the axial direction, for example, the inner cylinder 31
A thin film 25 (33) and a strip magnet 26 are placed on the outer peripheral surface of A.
(34) etc. may be arranged spirally. Also.

The thin film 25 (33), the band-shaped magnet 26 (34), etc. may be arranged to extend in the circumferential direction on the outer peripheral surface of the inner cylinder 31A, and in this case, the width dimension of the fiI film 25 (33) A movable magnet 28 (36) having a corresponding length may be provided at one location on the outer peripheral surface of the rotating shaft 27 (35).

Furthermore, in each of the above embodiments, the rotating shaft 27 is used as a rotating member.
(35) was described above, but instead of this,
For example, the rotating member may be constituted by an arm or the like fixed to various rotating shafts, and in this case, a movable magnet may be attached to the tip side of the arm or the like.

〔Effect of the invention〕

As detailed above, according to the present invention, a strip-shaped magnetoelectric conversion element is arranged between two conductive wires, a strip-shaped magnet is superimposed on one side of the magneto-electric conversion element, and the magneto-electric conversion element is placed under a magnetic field. A movable magnet is provided on a rotating member spaced apart on the other side of the magnetoelectric transducer, and the movable magnet forms a conductive region in the magnetoelectric transducer to short-circuit each conducting wire, thereby causing the movable magnet to short-circuit. Since the rotation angle is detected as a change in the resistance value between each conductor wire, the rotation angle of a rotating member can be detected over almost the entire range without contact, which not only improves performance but also simplifies the structure. , has various effects.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of a rotation angle detection device, FIG. 2 is an exploded perspective view of the device shown in FIG. 1, and FIG. is an explanatory diagram of the operation of the device shown in FIG. 1, FIG. 4 is an explanatory diagram of the principle of the device shown in FIG. 1, and FIG.
6 and 6 show the second embodiment, FIG. 5 is a cross-sectional view showing the rotation angle detection device assembled in the main body casing, and FIG. 6 shows the relationship between the rotation angle and the resistance value. FIG. 7 is an explanatory diagram showing a contact type rotation angle detection device according to the prior art, FIGS. 8 and 9 show other prior art,
Fig. 8 is an explanatory diagram showing a non-contact type rotation angle detection device, Fig. 9
The figure is a characteristic diagram of the device shown in Fig. 8.
...Lead wire, 25.33...Thin film, 26.34...
・Strip magnet, 27.35... Rotating shaft, 28.3
6... Movable magnet, 31... Main body casing,
31A...Inner cylinder, 31B...Outer cylinder, E...Conduction region, Fl. F2... Lines of magnetic force, G... Magnetic field. Patent Applicant Hitachi Construction Machinery Co., Ltd. Agent Patent Attorney Kazu Hirose Production Volume Naoki Nakamura Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7A Figure 8 Figure 9 Figure 4A

Claims (3)

[Claims] (1) Two conductive wires arranged a predetermined distance apart, at least one of which is a resistance wire, a strip-shaped magnetoelectric conversion element arranged between the conductive wires so as to fill the space between the conductive wires, and the magnetoelectric transducer. a strip-shaped magnet arranged so as to overlap one side of the magnetoelectric conversion element in order to place the conversion element under a magnetic field;
The movable magnet includes a rotating member spaced apart from the other surface of the magnetoelectric conversion element, and a movable magnet provided on the rotating member and having the same polarity as the strip magnet on the side facing the strip magnet. A rotation angle configured such that a magnet forms a conductive region in the magnetoelectric transducer due to the repulsion of a magnetic field, short-circuits the conductive wires, and detects the rotation angle of the movable magnet as a change in resistance value between the conductive wires. Detection device. (2) The rotation angle detection device according to claim (1), wherein the rotating member includes a rotating shaft, and the movable magnet is spirally arranged on the outer peripheral surface of the rotating shaft. (3) The rotation angle detection device according to claim (1) or (2), wherein the magnetoelectric conversion element is a magnetoresistive element.