JPH0469721B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention utilizes a magnetoresistive element whose resistance value changes depending on the direction of a magnetic field, and detects a position based on a change in the direction of the magnetic field. The present invention relates to a device that does this.

<Prior art> A magnetoresistive element is made of a special material, such as Ni-
It is constructed using a ferromagnetic material such as Co or a certain type of semiconductor, and the general structure is shown in Figure 5.

In the figure, reference numeral 1 denotes a pattern surface of the same electrical circuit made of the above-mentioned material, and has a shape in which comparatively long main electrical circuits 1a are bent in a zigzag shape so that they are lined up in parallel. Then, the two pattern surfaces 1, 1 are arranged with their main conductor paths 1a orthogonal to each other,
Connect in series and connect terminals 2, 3, and 4 at both ends and at the midpoint.
are provided respectively, and the lead wire 2 is connected as shown in Fig. 5b.
A, 3a, and 4a are connected to form a magnetoresistive element 5. 6 indicates an insulating substrate on which a patterned surface is formed. In this configuration, a constant voltage VCC is applied between terminals 2 and 3, and the potential of terminal 4 is taken out as output voltage Vo. Arrow M indicates the direction of the magnetic field, and if the angle θ is changed, the resistance values of the left and right pattern surfaces 1, 1 will increase or decrease in opposite directions, so the output voltage Vo will change according to the angle θ as shown in Figure 6.
changes in a sine curve.

Therefore, as shown in FIG. 7a, when the N and S poles of the magnets 7a and 7b are butted together and the magnetoresistive element 5 is moved along the magnets 7a and 7b, the abutting portion
Since the magnetic field is strongest near B' and the direction of the magnetic field changes here, the output voltage Vo changes as shown in FIG. 7b, and the position of the abutting portion B' can be detected.

<Problems to be solved by the invention> In the case of Fig. 7, points A', other than the abutting part B',
In C' etc., the magnetic field is weak, there is almost no change in output, and there is a high possibility of malfunction due to noise. Furthermore, the output change at the abutting portion B' is relatively gradual, making it difficult to improve detection accuracy.

The present invention has been made with attention to these points, with the aim of stabilizing the output and improving detection accuracy.

<Means for Solving the Problems> In order to achieve the above object, the position detection device using the magnetoresistive element of the present invention includes two strip-shaped magnetic bodies magnetized in the width direction perpendicular to the longitudinal direction. , magnetic field generating members arranged so that their magnetization directions are orthogonal to each other at predetermined positions in the longitudinal direction; and one strip-shaped member arranged so as to be relatively movable in the longitudinal direction along the magnetic field generating member. At least one pattern surface has a main conductor path parallel to the width direction of the magnetic material and at least one pattern surface has a main conductor path parallel to the width direction of the other strip-shaped magnetic material, and each pattern surface is used to generate a magnetic field. and a magnetoresistive element interlinked with the magnetic flux on the surface of the member. The arrangement direction of the two magnetic strips of the magnetic field generating member is, for example, such that the tip of one magnetic strip is connected to the tip of the other magnetic strip in the longitudinal direction. Two strip-shaped magnetic bodies are arranged so that the magnetization directions of the strip-shaped magnetic bodies successively arranged in the longitudinal direction are orthogonal to each other.

<Function> The direction of the magnetic flux on the surface of the magnetic field generating member is the width direction, and the direction changes by 90° at a predetermined position.
Therefore, when the magnetoresistive element moves along the magnetic field generating member, the direction of the magnetic flux interlinking with the pattern surface changes by 90 degrees at a predetermined position, and the resistance value of each pattern surface is
The output voltage increases and decreases in opposite directions from the maximum value to the minimum value or from the minimum value to the maximum value, and the output voltage changes greatly, allowing accurate position detection.

<Example> Hereinafter, the example shown in FIGS. 1 to 4 will be described.

In FIG. 1a, 11 is a magnetic field generating member which is a combination of two strip-shaped magnetic bodies 11a and 11b. Each of the strip-shaped magnetic bodies 11a and 11b is magnetized in its respective width direction, and is butted against each other at a position B to be detected with their width directions perpendicular to each other in an L-shape. In the case of the figure, one magnetic body 11a in part A
The right edge is the north pole and the left edge is the south pole, and the magnetic flux on the surface is directed to the left.The other magnetic body 11b in the C section has the top edge as the north pole and the bottom edge as the south pole. The magnetic flux is directed downward, and at position B, it is directed downward to the left. Note that the direction of the magnetic flux only needs to be horizontal on one side and vertical on the other, and there is no problem even if the magnetism of the magnetic poles is reversed.

The magnetoresistive element 5 is placed in the magnetic field of the magnetic field generating member 11, and is configured to be able to move relatively along the magnetic field generating member 11 as shown by arrow D. The same magnetoresistive element 5 as described in FIG. 5 can be used, and one pattern surface has a magnetic material 11a.
The pattern surface is parallel to the width direction of the pattern surface, and the other pattern surface is perpendicular to the pattern surface. Magnetoresistive element 5
The relationship between the magnitudes of the resistance values on each pattern surface is reversed between when it is in the A section and when it is in the C section, and as shown in Figure 2, the output voltage Vo is, for example, the lowest in the A section. is the position B that the magnetoresistive element 5 wants to detect.
After passing through and reaching part C, the output voltage Vo is inverted and reaches its maximum value. Therefore, due to this change in the output voltage Vo, the magnetoresistive element 5 and the magnetic field generating member 11
The relative positional relationship between the position B and the desired position B can be detected, and the position detection can be performed in the same way as the on/off operation of a contact by a limit switch.

Note that the shape of the magnetic field generating member 11 is not limited to the linear shape shown in the figure, but can be any suitable shape such as a curved shape depending on the shape and movement of the object. Moreover, the magnetic bodies 11a, 1 at position B
The combinations 1b can also be mutually arranged so that their side edges overlap by a certain length L, as shown in b in FIG. 1. In this case, the output voltage at position B
The change in Vo becomes gradual depending on the overlap dimension L. Conversely, if mutual magnetic fields extend, the magnetic bodies 11a and 11b may be separated, and the magnetic bodies 11a and 11b may be separated from each other.
The mutual arrangement of a and 11b may be selected as appropriate depending on the application and the like.

3 and 4 show strip magnetic bodies 11a, 1
Other examples of the combinations 1b are shown; FIG. 3 shows magnetic materials 11a and 11b crossed at right angles so that their width directions are cross-shaped, and FIG. They are shown perpendicularly so that In the case of FIG. 3, the magnetoresistive element 5 can be placed either above or below the magnetic body 11a or on the left or right side of the magnetic body 11b, as shown as 5a to 5d in b of the same figure. Further, in the case of FIG. 4, as shown as 5a and 5b in b of the same figure, the magnetic body 11a can be placed at any position above or below the magnetic body 11a. Therefore, the degree of freedom regarding the arrangement of the magnetoresistive element 5 is increased, and the practicality is improved.

<Effects of the Invention> As is clear from the description of the above-mentioned embodiments, the present invention provides a magnetic field generating member that is formed by abutting two strip-shaped magnetic bodies magnetized in the width direction so that their magnetization directions are perpendicular to each other. Accordingly, the position is detected by relatively moving the magnetoresistive element and inverting the output voltage due to a change in the resistance of the magnetoresistive element. Therefore, since it is a non-contact type, there will be no interference with the double action of the detected object, and since it is a non-contact type, there is no possibility of contact failures that occur with contact type devices such as limit switches. ,
Also, the change in output voltage at a given position is clear,
Since the magnetoresistive element is always in a magnetic field, it is possible to obtain a highly reliable position detection device with features such as stable output and no malfunction due to external noise.

[Brief explanation of the drawing]

FIG. 1a is a schematic perspective view of an embodiment of the present invention;
b in the same figure is a perspective view of the main part of a modified example, FIG. 2 is an output voltage diagram of the same as above, a and b in FIG. a,
b is a perspective view and a front view of essential parts of different embodiments, a and b of FIG. 5 are a pattern diagram and a perspective view of a magnetoresistive element, respectively, FIG. 6 is an output voltage diagram of the same element, and FIG. 7 Figures a and b are a schematic side view and an output voltage diagram of a conventional example, respectively. 1...Pattern surface, 1a...Main conductor path, 5...
Magnetoresistive element, 11... Magnetic field generating member, 11a,
11b...Strip magnetic material.

Claims (1)

[Scope of Claims] 1. A magnetic field generating member in which two magnetic strips magnetized in the width direction perpendicular to the longitudinal direction are butted against each other at a predetermined position in the longitudinal direction so that the magnetization directions are perpendicular to each other; A pattern surface that is arranged so as to be relatively movable in the longitudinal direction of the magnetic field generating member along the generating member, and has a main conductive path parallel to the width direction of one of the magnetic strips, and a pattern surface of the other magnetic strip. A magnetoresistive element comprising at least one patterned surface having a main current path parallel to the width direction, each patterned surface interlinked with the magnetic flux on the surface of the magnetic field generating member. A position detection device using a magnetoresistive element.