JPH077725B2 - Non-contact type potentiometer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a non-contact potentiometer for rotating a rotor, and more particularly to a non-contact potentiometer using a ferromagnetic magnetoresistive element whose resistance value is reduced by magnetic force. It is about.

[Prior Art] A magnetic circuit of a non-contact type potentiometer has conventionally been configured as a closed magnetic circuit together with a bottomed cylindrical core, a rotating magnetic body and a permanent magnet, and has a magnetic resistance in a gap formed at a tip portion of the rotating magnetic body. The element InSn is arranged to generate an output according to the rotation of the rotating magnetic body. Then,
By changing the size of the gap formed at the tip of the rotating magnetic body, in other words, by processing the tip of the rotating magnetic body into a predetermined shape, a predetermined function output can be obtained from the InSb magnetoresistive element as described above. It has gained.

[Problems to be Solved by the Invention] In this case, as disclosed in Japanese Patent Application No. 61-72201, since the permanent magnet is bent in a semi-circular shape, when it is magnetized in the radial direction. However, this method has a problem that it is difficult to magnetize.

The present invention has been made in view of the above circumstances, and by forming the magnetic field generating means from a flexible material, it is possible to preliminarily magnetize in a linear state, and such magnetization is extremely easily performed. It is an object of the present invention to provide a non-contact type potentiometer having such excellent effects.

[Means for Solving the Problems] According to the present invention, a housing, a rotor rotatably provided in the housing, and a rotor that is concentric with the rotor and is spaced apart from the rotor by a predetermined distance are provided. And a magnetic field generating means mounted on the rotor side so as to form a closed magnetic circuit with the ferromagnetic magnetoresistive element. The magnetic recording medium is formed of a flexible magnetic material, and the magnetic field generating means is magnetized in a straight line before being bent into a predetermined shape.

[Operation] According to the present invention configured as described above, since the magnetic field generating means is formed of the flexible material, the magnetic field generating means is in a straight line state before being bent into a predetermined shape in the thickness direction. Can be magnetized, and a strong magnetic field can be applied by a large-sized magnetizer, which facilitates the magnetization.

[Effect of the Invention] According to the present invention configured as described above, the magnetic field generating means is formed of a flexible material, so that the magnetic field generating means is magnetized in a straight line state before being formed in a non-linear shape. Therefore, it is possible to provide a non-contact potentiometer having an excellent effect that the magnetization is performed and the cost is reduced.

Embodiments Embodiments of the present invention will be described below with reference to the drawings. First
An embodiment of the present invention is shown in the drawing, a top view of the same is shown in FIG. The configuration shown in the figure is a circular or polygonal shape having an opening on an insulating substrate 1 as a circuit substrate,
Fe, Ni-Co ferromagnetic thin film magnetoresistive element 2a,
2b is formed, and one end 3 of the opening is connected to the power supply voltage Vcc.
, And the other terminal 4 is grounded (GND).
Further, the output terminals 5 are connected so as to be taken out as the output Vout from the ferromagnetic magnetoresistive elements 2a and 2b. And
A semicircular arc-shaped permanent magnet 6 is attached to the ferromagnetic magnetoresistive elements 2a, 2b of the insulating substrate 1 as a field generating means at a predetermined distance from the ferromagnetic magnetoresistive elements 2a, 2b.

This state or mode will be described in more detail with reference to FIG. 2. A disk-shaped rotor 8 is provided in a cylindrical housing 7 with a closed upper end, and a rotary shaft 9 of the rotor 8 is provided.
Are oriented in the vertical direction, penetrate the upper surface of the housing 7, and are supported by bearings 10. A case 11 is provided in a closed state at the lower end opening of the housing 7, and an insulating substrate 1 is mounted on the upper surface of the case 11. The permanent magnet 6 as a magnetic field generating means has a semicircular arc shape, which is attached to the outer peripheral surface of the rotor 8 and is arranged so as to be concentric with the outer periphery of the ferromagnetic magnetoresistive elements 2a and 2b. At this time, at both ends of the permanent magnet 6, relief portions 6a, 6b formed so as to be directed outwardly.
Thus, the magnetic field is prevented from reaching the ferromagnetic magnetoresistive elements 2a and 2b on the side opposite to the permanent magnet 6 as much as possible.

The permanent magnet 6 has magnetic material powder dispersed in a flexible material such as styrene-butadiene rubber (SBR), and is magnetized in this direction in the radial direction as indicated by the symbol M in FIG. 1 (a). ing. A closed magnetic circuit is formed by the permanent magnet 6 and the ferromagnetic magnetoresistive element 2a as shown by the symbol i in FIG. 1 (b).

Further, the permanent magnet 6 rotates in the circumferential direction of the ferromagnetic magnetoresistive elements 2a and 2b with the centers of the ferromagnetic magnetoresistive elements 2a and 2b as the centers of rotation axes. In an actual embodiment, the absolute value of the strength of the magnetic field generated toward 2a is set to be equal to or higher than the saturation magnetic field strength of the ferromagnetic magnetoresistive element 2a. The magnetic field is applied in the direction perpendicular to the circumferential direction of the ferromagnetic magnetoresistive element 2a, that is, in the radial direction.

Next, the operation of the potentiometer configured as described above will be described.

When the permanent magnet 6 receives a magnetic field from the direction perpendicular to the current direction, the resistance values of the ferromagnetic magnetoresistive elements 2a and 2b decrease. And the permanent magnet 6 is the ferromagnetic magnetoresistive element 2a, 2b.
By rotating in the circumferential direction, the portion where the resistance value decreases in the ferromagnetic magnetoresistive element 2a also continuously rotates. Therefore, the resistance value between the ground terminal and the output terminal Vout and the output terminal Vout
The value of the output Vout as a divided voltage value of the power supply voltage Vcc determined by the ratio between the resistance value of the power supply voltage Vcc and the resistance value of the power supply voltage Vcc terminal has a straight linearity as shown in FIG.

The rotation angle Odeg in FIG. 3 means that the straight side 6c of the permanent magnet 6 in FIG. 1 is perpendicular to the line XX in the drawing, and the permanent magnet 6 is arranged on the left side in the drawing. .
Further, although FIG. 3 shows the characteristic of right rotation from that position in FIG. 1, the rotation direction may be left or right depending on the desired need.

When the ferromagnetic magnetoresistive elements 2a and 2b receive a magnetic field strength (absolute value) equal to or higher than the saturation magnetic field (dashed-dotted line) as shown by the characteristic (solid line) in the graph of FIG. Therefore, the value of the output Vout does not depend on the mounting error of the permanent magnet 6 and the slight fluctuation of the magnetizing strength in the embodiment. It should be noted that the characteristic of InSb is shown by a dotted line in FIG. 4, but it can be seen that the resistance value of InSb increases as the magnetic field strength increases.

As described above, in the above configuration, since the permanent magnet 6 is formed of the flexible material in which the magnetic powder is dispersed, the permanent magnet 6 can be magnetized in the thickness direction in a linear state during the magnetization. It is possible to provide a non-contact type potentiometer having a remarkably excellent effect that it becomes extremely easy.

Next, FIGS. 5 (a) and 5 (b) show a second embodiment of the present invention. The difference between the second embodiment and the first embodiment is as follows. That is, in the first embodiment, the permanent magnet 6 is located on the outer periphery of the ferromagnetic magnetoresistive elements 2a and 2b, but in the second embodiment, the average radius of the permanent magnet 6 and the ferromagnetic magnetoresistive elements 2a and 2b. And the permanent magnet 6 and the ferromagnetic magnetoresistive element 2a are positioned so as to correspond to each other in the vertical direction. Further, in this second embodiment, the escape portion 6 of the first embodiment is used.
a and 6b are omitted. What if this escape part 6a, 6
b is not always necessary, and may be omitted if unnecessary, and the essential point may be configured to be provided as needed.

Even with this structure, the same effect as that of the first embodiment can be obtained. In the second embodiment, the same parts as those in the first embodiment are designated by the same reference numerals and only different parts are described.

6 (a) and 6 (b) show a third embodiment of the present invention.
In the third embodiment, the magnetizing direction of the permanent magnet 6 in the first embodiment is perpendicular to the radial direction as indicated by the symbol M'in FIG. 6 (b). Then, a magnetic path as indicated by the symbol i in the figure is formed.

7 (a) and 7 (b) show a fourth embodiment of the present invention.
In the fourth embodiment, the magnetizing direction of the permanent magnet 6 in the second embodiment is perpendicular to the thickness direction as indicated by the symbol M ″ in FIG. 7 (b). A magnetic path shown by i is formed.

Although the ferromagnetic magnetoresistive elements 2a and 2b have a circular or polygonal shape in the above embodiment, the shape is not limited to this and may be, for example, a strip shape. In addition, the rotor is configured as a novel one that has both rotational displacement and linear displacement,
You may comprise so that these both displacements may be taken out, respectively. Alternatively, the rotational displacement and the linear displacement of the rotor may be taken out at the same time.

Further, in the above embodiment, the permanent magnet 6 as the magnetic field generating means is used.
Styrene butadiene rubber was used to form the above, but the present invention is not limited to this, and the point is to use a flexible material such as plastic that can freely flex in any direction.

In addition, in concrete implementation, various modifications can be made without departing from the gist of the invention.

[Brief description of drawings]

FIG. 1 shows an embodiment of the potentiometer of the present invention. FIG. 1 (a) is a top view thereof and FIG. 1 (b) is a sectional view taken along line XX. 2 is a longitudinal sectional view, FIG. 3 is a graph showing output characteristics of the embodiment shown in FIG. 1, FIG. 4 is a graph showing characteristics of a ferromagnetic magnetoresistive element, and FIGS. 5 (a) and 5 (b).
Is a top view and a sectional view showing a second embodiment of the present invention.
7A and 7B are a top view and a sectional view showing a third embodiment of the present invention, and FIGS. 7A and 7B are a top view and a sectional view showing a fourth embodiment of the present invention. FIG. 8 is a graph showing output characteristics. In the figure, 1 ... Insulating substrate (circuit board), 2a, 2b ... Ferromagnetic magnetoresistive element, 6 ... Permanent magnet (magnetic field generating means), 7 ...
… Housing, 8 …… Rotor, 9 …… Rotary shaft, 10 …… Bearing

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Ao 1-1, Showa-cho, Kariya city, Aichi prefecture Nihon Denso Co., Ltd. (72) Inventor Toshikazu Arasa 1-1-chome, Showa town, Kariya city, Aichi prefecture Sozo Co., Ltd.

Claims (4)

[Claims] 1. A housing, a rotor rotatably provided in the housing, and a ferromagnetic magnetoresistive element which is concentric with the rotor and is arranged at a predetermined distance from the rotor. An insulating substrate having: and a magnetic field generating means mounted on the rotor side so as to form a closed magnetic path with the ferromagnetic magnetoresistive element, the magnetic field generating means being formed of a flexible magnetic material, A non-contact potentiometer, wherein the magnetic field generating means is magnetized in a straight line before being bent into a predetermined shape. 2. The non-contact potentiometer according to claim 1, wherein the magnetic field generating means has relief portions directed toward the outside at both ends. 3. The non-contact potentiometer according to claim 1, wherein the magnetic field generating means comprises a material made by dispersing magnetic material powder in a flexible plastic. 4. The non-contact potentiometer according to claim 1, wherein the magnetic field generating means is arranged concentrically with the ferromagnetic magnetoresistive element.