JPS6031014A - Position sensor wherein magnetoresistance body is used - Google Patents

Abstract

PURPOSE:To supply a correct signal voltage in a sine wave shape from an intermediate terminal, by forming an irregular period, during which moving magnetic flux is changed with respect to the end surface of each magnetoresistance body. CONSTITUTION:A permanent magnet 4 forms a parallel magnetic field H. Magnetoresistance bodies 1, 1', 10 and 10' comprising InSb are provided on a yoke and supporting body 3 comprising a ferromagnetic body. The thickness of the magnetoresistance body is about 5mum, the width is 0.3mm., and the height (h) is 1.5mm.. The magnetoresistance bodies 1, 1', 10 and 10' are connected in series by conductor paths 5 formed by a copper film. Terminals 11 and 12 and an intermediate terminal 13 are provided. The magnetoresistance bodies 1, 1', 10 and 10' and the conductor paths 5 are formed by combining a vacuum evaporation method and the like and a bonding method using a bonding material.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to an improvement in a position sensor using a magnetoresistive element. In particular, it has at least one series circuit configured with two magnetoresistive elements (or a group of magnetoresistive elements),
An alternating current voltage is applied to each of the hani, and the strength of the magnetic field produced by each of the two magnetoresistive elements (or a group of magnetoresistive elements) is alternately changed, and the potential of the intermediate terminal of the series circuit is changed. The present invention relates to an improvement in a position sensor that measures changes in the voltage so that the alternating current voltage obtained as a change in the potential of the intermediate terminal becomes a correct sine wave.

(2) Background of the technology There are materials such as indium antimonide (In5b) and indium arsenide (rnAs) that change their resistance in response to the strength of the magnetic field, and are called magnetoresistive materials. An element made of such a magnetoresistive material (hereinafter referred to as a magnetoresistive element) is placed in a magnetic field, and a geometric shape is formed so as to give regular changes to the reluctance of the magnetic path between the magnetoresistive element and the Bunraku magnetic path. When an object is moved along a magnetoresistive element, the resistance of the magnetoresistive element changes in accordance with the regular changes in roughtance, so the moving state such as the position and speed of the object can be detected. I can do it.

(3) Prior art and problems A position sensor using a magnetoresistive element based on the above basic principle can be realized using one magnetoresistive element, but as shown in Fig. Magnetoresistive elements 1.1' are connected in series and a voltage is applied between the two terminals 11.12 of this series circuit. The two magnetoresistive elements 1, lo
Slits 23.23°, 23″, 23.23°, 23″,
The object 24 having φ and made of a magnetic material is moved in the direction of A in the figure, or the protrusions 21, 21', 21'', . . . 22.22', 22", .Φ. The object 2 made of a magnetic material is moved in the direction of arrow A in the figure, and the slit 23 or the like or the protrusion 21 is removed from the intermediate terminal 13 of the series circuit. It is common to obtain an alternating current voltage with the same period as the period corresponding to the alternating movement of the recesses 22 and the like.

Furthermore, as shown in FIGS. 3 and 4, the above-mentioned position sensor 2
By arranging the sets at positions with electrical angles different from each other by 90° and obtaining two AC voltages with a phase difference of 800° from each other, position detection accuracy will be improved and the direction of rotation can be easily identified. What is possible is clear from the equation below.

A cos θ sin ω t +As1n θ C
OS ω t=Bsin (ω is 10) where θ is the electrical angular position to be detected, and ω is the electrical angular velocity of the AC voltage applied to the terminals 11 and 12 of the series circuit.

In FIG. 3, the set of magnetoresistive elements 1.1' is in contact with the slit 23 and the magnetic material part 24 without a slit, while the set of magnetoresistive elements 1O110 is in contact with the magnetic material part 24 and the slit 23'. The boundary between the slit 23° and the magnetic material part 2
4, and their electrical angle positions are shifted by 80° from each other. On the other hand, in FIG. 4, the magnetic resistor 1.
The set 1' is in contact with the protrusion 21 and the recess 22, while the set of magnetoresistive element 1O110 is in contact with the boundary between the recess 22 and the protrusion 21' and the boundary between the protrusion 21' and the recess 22''. The electrical angle positions are shifted by 80° from each other.

In order to correctly realize the function based on the above equation, the AC output obtained from the intermediate terminal of each magnetoresistive pair needs to be a correct sine wave or cosine wave.

The fifth
As shown in FIG. 6, the distance between the centers of the two magnetic resistors 1.1', the width P1 of the slit 23 or protrusion 21, and the radius P of the magnetic member 24 or recess 22 without a slit.
Although it is effective to make the magnetoresistive elements 1 and 2 the same, it is geometrically difficult to arrange them in this way, and the width of the magnetoresistive elements 1 and lo becomes large.
There is a drawback that the resistance of o becomes extremely small, making it impractical for practical use, and it is difficult to practically adopt the structures shown in FIGS. 5 and 6.

Therefore, in the prior art, as shown in FIGS. 7 and 8, the width of the magnetoresistive elements l and 1' is made small, and
Generally, the width P1 of the slit 23 or the protrusion 21 is made small, and the width P2 of the magnetic material part 24 or the recessed part 22 which does not have a slit is made large.

As a result, in the prior art, the voltage waveform obtained from the intermediate terminal 13 of the series circuit of magnetoresistive elements inevitably tends to include a third high frequency wave whose phase is reversed, as shown by E in FIG. There were drawbacks.

(4) Purpose of the Invention The purpose of the present invention is to eliminate this drawback. Apply a voltage, alternately change the strength of the magnetic field crossed by each of the two magnetoresistive elements (or group of magnetoresistive elements), and measure the change in potential at the intermediate terminal of each of the series circuits. A position sensor formed by using a magnetoresistive element, which can supply a correct sinusoidal signal voltage from an intermediate terminal of a series circuit of two magnetoresistive elements (or a group of magnetoresistive elements). Our goal is to provide the following.

(5) Configuration of the Invention The configuration of the present invention is such that the magnetic flux is disposed in a region that intersects with a magnetic flux that moves in a specific direction and whose magnetic field intensity changes periodically, so as to be approximately parallel to the moving direction of the magnetic flux. At least one set of series circuits each consisting of two magnetoresistive elements (or a group of magnetoresistive elements) each made of a rectangular parallelepiped plate-like member whose end face intersects with the direction of movement of the magnetic flux and is provided with an intermediate terminal is provided. The two magnetoresistive elements (or a group of magnetoresistive elements), which change in accordance with the magnetic field strength, perform bunraku with two magnetoresistive elements (or a group of magnetic resistance elements) by applying an alternating voltage to each circuit. A position sensor using a magnetoresistive element, which detects the moving state of the moving magnetic flux by measuring the potential of each of the intermediate terminals that occurs in response to a change in the resistance value of a group of magnetoresistive elements. In the position sensor using a magnetoresistive member, the timing at which the moving magnetic flux changes is made to be irregular with respect to the end face of the magnetoresistive member.

As shown in FIGS. 10 and 11, the technical idea on which the present invention is based is that the rectangular parallelepiped magnetoresistance body 1 arranged in the vertical direction, the end face of lo, the slit 23 etc. that cause a change in reluctance, etc. Alternatively, a time difference is generated in the timing at which each part of the end face of the protrusion 21 etc. starts to come into contact with each other, thereby preventing the generation of harmonics as a whole.

If necessary, the timing at which the moving magnetic flux alternates is made irregular with respect to each part of the end face of the magnetoresistive element, and as a whole,
This prevents the generation of harmonics and makes the waveform of the moving magnetic field sinusoidal.

In order to realize this technical idea, as mentioned above, the end face of the magnetoresistive element 1 etc. and the end face of the slit 23 etc. or the protrusion 21 etc. should not be made to match, and these slits 23 etc. or the protrusion 2
The end face of the first class may be made irregularly shaped with respect to the moving direction of the magnetic flux.

In terms of structure, when the object 24 or 2 (object that changes reluctance) having the slit 23 or the like or the protrusion 21 is a linear member, that is, a rod-like member, as shown in FIGS. 10 and 11, The end faces of the slits 23, etc. or the protrusions 21, etc. are inclined with respect to the end faces of the magnetoresistive element 1.1', and as shown in FIGS. 12 and 13, the end faces of the slits 23, etc. or the protrusions 21, etc. As shown in FIGS. 14 and 15, the center part of the end surface of the slit 23 or the protrusion 21 should not be made to meander with respect to the end surface of the magnetic resistor 1.1'.
18 and 17.
As shown in the figure, the end surfaces of the slits 23, etc. or the protrusions 21, etc. may be made step-like with respect to the end surfaces of the magnetic resistance elements 1 and 1''.

Further, the object having the slit 23 or the like or the protrusion 21 (the object that changes the reluctance) may be a cylindrical member,
In that case, the circumferential surface of the cylindrical member is
It suffices if it is made irregular with respect to the moving direction of the magnetic flux as shown in FIG. 717.

(6) Embodiments of the Invention Since the structure of the present invention is relatively clear, a position sensor using a magnetic resistor according to a typical embodiment of the present invention will be further explained below with reference to the drawings. .

18 and 19 are two examples of position sensors made using the magnetic resistance bodies according to claims 2 and 4, respectively (FIG. 18 shows the former, that is, an object having a slit or a protrusion is FIG. 19 is a plan view of the latter case, that is, the case where the object having a slit or projection is a cylindrical member. Note that the number of series circuits is two.

In the figure, 4 is a permanent magnet, which forms a parallel magnetic field H of about 1 kilogauss. Reference numeral 3 denotes a yoke/support body made of a ferromagnetic material such as ferrite, and in this example, the height is several meters, the width is several layers, and the thickness is about 0.5 mm.

1.1', 10.10° are indium antimonide (
It is a magnetoresistive material made of Ir+Sb) and has a thickness of approximately 51 mm.
It is Lm. Its width is 0.3ms, and its height h
is 1. It is about F+++m. The magnetoresistive elements 1, 1' and 10.10° are connected in series through a conductive path 5 formed of a copper film, and terminals 11, 12 and an intermediate terminal 13 are provided on both sides. Magnetoresistive element l, 1°, 1
0, lOo and the conductive path 5 can be easily formed by a combination of a photolithography method, an ion blating method, a sputtering method, a vacuum evaporation method, etc., and an adhesion method using an adhesive. It goes without saying that two sets of magnetoresistive elements having such a structure are arranged as shown in FIG. 24 is a plate-like member having a slit, 241 is a cylindrical member having a slit 231,
It rotates around the axis 6, and the magnetoresistive elements 1.1', 1O1
10' is arranged at a distance of about 0.3 ms.

Refer to Figure 10 again. In both cases, the end faces of the slits 23, 231, etc. are the 11th
As shown in the figure, rectangular parallelepiped magnetoresistive elements l, 1゛, 10
．． It is inclined with respect to the end face of 10'.

When a voltage of about 5 Bi is applied between the terminals 11 and 12 of a position sensor made using a magnetoresistive member having the above structure, the potential of the intermediate terminal 13 becomes such that the slits 23, 231, etc. are 1.1° ±0. with the same period as the period opposite to.
It alternates with a waveform extremely close to a 2V sine wave.

Since the structure of the present invention is relatively clear, it will not be necessary to describe the entire scope of the claims.

(7) Effect of the invention 5 As explained above, according to the present invention, there is at least one series circuit configured with two magnetoresistive elements (or a group of magnetoresistive elements), and an alternating current voltage is applied to each of the series circuits. This is done by alternately changing the strength of the magnetic field produced by each of the two magnetoresistive elements (or a group of magnetoresistive elements) and measuring the change in potential at the intermediate terminal of each of the series circuits. To provide a position sensor using a magnetoresistive member, which can supply a correct sinusoidal signal voltage from an intermediate terminal of a series circuit of the two magnetoresistive members (or a group of magnetoresistive members). be able to.

[Brief explanation of the drawing]

FIGS. 1 and 2 are perspective views of an example of a position sensor using a magnetoresistive element in the prior art. Figures 3 and 4
The figure is a plan view of an example of a position sensor using a conventional magnetic resistor having two series circuits of magnetic resistors. 5, 6, 7, and 8 show the disadvantages of an example of a position sensor using a magnetoresistive body in the prior art shown in FIGS. 3 and 4, namely, the present invention. FIG. 2 is a plan view of an example of a position sensor made using a magnetoresistive body in the prior art, written for detailed explanation of the present invention. FIG. 9 is a diagram showing an output voltage obtained from an intermediate terminal of an example of a position sensor using a magnetic resistor according to the prior art shown in FIGS. 7 and 8. FIG. FIGS. 1O and 11 illustrate the operating principle of a position sensor made using the magnetoresistive elements according to claims 2 and 3, which are limited by claim 6, respectively. FIG. Figure 12, Figure 13, Figure 14, Figure 15, Figure 1
8 and 17 are front views of a moving object and a magnetic resistor of a position sensor using a magnetic resistor according to an embodiment of the present invention. FIGS. 18 and 19 are plan views of a position sensor using a magnetoresistive element according to an embodiment of the present invention. l, 1°, 10.10°, ... magnetoresistive element, 11.
12・φ・Magnetic resistance terminal, ! 3・φ・Intermediate terminal of magnetic resistor, 2.24・・φ Moving object, 241−・−
Rotating body, 21.2 bi, 21”, 121, 12
1'・φ・Protrusion, 22.22', 22", 12
2, 122', ψ... recess, 23.23°, 23"
, 231.231,...slit, H...φ magnetic field direction, A-...direction of movement of object, vertical...width of e magnetic resistor, L...distance between centers of magnetic resistors forming a pair. ,
Pl...width of protrusion, P...width of four parts, E@...
Voltage waveform obtained from the intermediate terminal of a position sensor made using a magnetoresistive element in the prior art, 3...Yoke and support member, 4...Permanent magnet, 5...Conducting path, 6.Fist/rotation body axis. Agent Patent Attorney Makoto Samukawa −

Claims (9)

[Claims] (1) An end face that is arranged to be roughly parallel to the moving direction of the magnetic flux in a region that plays Bunraku with a magnetic flux that moves in a specific direction and whose magnetic field strength changes periodically, and that intersects with the moving direction of the magnetic flux is At least one set of series circuits each consisting of two magnetoresistive elements (or a group of magnetoresistive elements) each made of a rectangular parallelepiped plate member orthogonal to the direction of movement and provided with an intermediate terminal is arranged, and each circuit is connected to an alternating current voltage. are applied, and 2
The state of movement of the moving magnetic flux is detected by measuring the potential of each of the intermediate terminals that occurs in response to a change in the resistance value of an individual (or a group of magnetoresistive elements), using a magnetoresistive element. 1. A position sensor using a magnetic resistor, characterized in that the timing at which the moving magnetic flux changes is irregular with respect to an end surface of the magnetic resistor. (2) The magnetic flux that moves in the specific direction and periodically changes its magnetic field strength is generated by the magnetic flux generating means disposed opposite to one surface of the at least one set of magnetoresistive circuits; A patent that is realized by a change in roughtance caused by movement of a rod-shaped member having regularly formed slits and moving in opposition to a magnetoresistive element (or a group of magnetoresistive elements) in the specific direction. A position sensor made using the magnetic resistor according to claim 1. (3) The magnetic flux that moves in the specific direction and periodically changes its magnetic field strength is generated by the magnetic flux generating means disposed opposite to one surface of the at least one set of magnetoresistive circuits; This is realized by the change in roughness caused by the movement in the specific direction of a rod-shaped member having regularly formed rack-like unevenness that moves opposite to a magnetoresistive element (or a group of magnetoresistive elements). , a position sensor using the magnetic resistance body according to claim 1. (4) The magnetic flux that moves in the specific direction and periodically changes its magnetic field strength is generated by the magnetic flux generating means disposed opposite to one surface of the at least one set of magnetoresistive circuits; A change in rufftance caused by rotation of a cylindrical member that moves oppositely to a magnetoresistive element (or a group of magnetoresistive elements) and that has regularly formed slits. A position sensor made using the magnetic resistor described in item 1. (5) The magnetic flux that moves in the specific direction and periodically changes its magnetic field strength is generated by the magnetic flux generating means disposed opposite to one surface of the at least one set of magnetoresistive circuits; A change in roughness caused by rotation of a cylindrical member that moves oppositely to a magnetoresistive element (or a group of magnetoresistive elements) and has regularly formed gear-like unevenness. A position sensor made using the magnetoresistive material described in scope 1. (6) The time when the moving magnetic flux changes with respect to the end face of the magnetic resistance body is determined when the moving magnetic flux changes with respect to the end face of the slit or rack-like unevenness of the rod-shaped member or the slit or gear-like unevenness of the cylindrical member. A position sensor made using the magnetic resistance body according to claim 2, 3, 4, or 5, which is irregular due to being inclined with respect to the direction of movement. (7) The timing at which the moving magnetic flux changes with respect to the end face of the magnetic resistance body is determined when the slit or rack-like unevenness of the rod-shaped member or the end face of the slit or gear-like unevenness of the cylindrical member A position sensor made using the magnetic resistance body according to claim 2, 3, 4, or 5, which is irregular due to meandering with respect to the moving direction. (8) When the moving magnetic flux changes with respect to the end face of the magnetic resistance body, the central portion of the slit or rack-like unevenness of the rod-shaped member or the slit or gear-like unevenness of the cylindrical member becomes enormous. Claims 2, 3, 4, or 5 that are irregular due to
A position sensor made using the magnetoresistive material described in 2. (9) When the moving magnetic flux changes with respect to the end surface of the magnetic resistance body, the end surface of the slit or rack-like unevenness of the rod-shaped member or the slit or gear-like unevenness of the cylindrical member has a step-like shape. Claims 2, 3, 4, or 5 that are considered irregular by
A position sensor made using the magnetoresistive material described in 2.