JP2000182809A - Slide-type variable resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable resistor which can obtain sufficient resolution with satisfactory accuracy, when a slide distance is short and can readily make it a waterproof structure. SOLUTION: This slide-type variable resistor is provided with a magnetic sensor 10, in which magnetoresistance elements R1-R4, whose resistance values change with respect to the direction of the applied magnetic field are arranged, and a magnet 50 which slides and moves to the magnetic sensor 10 and applied a magnetic field to the magneto resistance elements R1-R4 in accordance with the sliding position. By sliding and moving the magnet 50 with respect to the magnetic sensor 10, the direction of the magnetic field applied to the magnetoresistance elements R1-R4 is changed, and their resistance values are changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding variable resistor.

[0002]

2. Description of the Related Art Conventionally, a slide type variable resistor generally comprises:
A substrate in which a linear resistor pattern and a conductor pattern are provided in parallel, and a sliding type object mounted on the substrate,
By sliding the sliding-type object on the substrate, the slider attached to the sliding-type object is brought into sliding contact with the resistor pattern and the conductor pattern. It was configured to change the resistance value.

[0003] On the other hand, in order to detect subtle changes in members, there has been a demand for electrical equipment having a very short sliding distance (for example, about 1 mm) of a sliding variable resistor.

[0004]

However, in the above-mentioned conventional slide-type variable resistor, when the sliding distance of the sliding type object is reduced to, for example, about 1 mm, the moving distance of the slider on the resistor pattern becomes short. Therefore, there is a problem that a sufficient resolution cannot be obtained.

Also, in the conventional slide type variable resistor, since the slider is in sliding contact with the resistor pattern, a waterproof coat cannot be formed on the resistor pattern, and a portion requiring waterproofness is required. In such a case, it is necessary to make the whole of the slide type variable resistor a waterproof structure, so that the structure is complicated and the size cannot be reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a slide type variable resistor which can obtain a sufficient resolution with high accuracy even if the slide distance is short and which can easily be made to have a waterproof structure. To provide equipment.

[0007]

In order to solve the above-mentioned problems, a sliding variable resistor according to the present invention comprises a magnetic sensor provided with a magnetoresistive element whose resistance value changes in accordance with the direction of an applied magnetic field; A magnet that slides with respect to the magnetic sensor and changes the direction of a magnetic field to be applied in accordance with the slide position with respect to the magnetoresistive element, and slides the magnet relative to the magnetic sensor. In this case, the resistance value of the magnetoresistive element is changed. Further, the magnet is plate-shaped, and by providing an N magnetic pole and an S magnetic pole on one surface of the magnet, the direction of the magnetic field is substantially perpendicular to the magnet surface just above the N and S magnetic poles.
At the intermediate position between the N and S magnetic poles, it is configured to be substantially parallel,
Thereby, the direction of the magnetic field applied to the magnetoresistive element is changed by sliding the magnet relative to the magnetoresistive element.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an exploded perspective view showing one embodiment of a slide type variable resistor to which the present invention is applied. As shown in the figure, the sliding variable resistor includes a magnet 50 on a mounting substrate 30 on which the magnetic sensor 10 is mounted.
The sliding type object (magnet mounting member) 40 on which is mounted is placed,
A case 60 is mounted thereon. Hereinafter, each component will be described.

The magnetic sensor 10 has four magnetoresistive patterns (magnetic resistance elements) R1, R2, R
3, R4 are provided, and a drawing pattern (not shown) is drawn from each of the magnetoresistive patterns R1 to R4, and a metal terminal 13 is connected to an end of each drawing pattern. FIG. 2 shows a connection state of each of the magnetoresistive patterns R1 to R4. The substrate 11 is fixed on the mounting substrate 30 with an adhesive or the like. At this time, the lower ends of the four metal terminals 13 project from the lower surface of the mounting substrate 30 through slits (not shown) provided in the mounting substrate 30. .
Notches 31 are provided on a pair of opposed sides of the mounting substrate 30.

Here, the magnetoresistive patterns R1 to R4 are formed of a ferromagnetic material such as permalloy, and the substrate 11 is made of glass, silicon, or the like.
Is composed of a laminated insulating plate or the like.

FIG. 3 is an exploded perspective view of the sliding type object (magnet mounting member) 40 and the magnet 50 as viewed from below. FIG. 1 and FIG.
As shown in FIG. 5, the sliding mold 40 is made of a molded resin, and a knob 45 is provided on the upper surface of a rectangular mold body 41, and legs 43, 43 are provided downward from both ends thereof. The magnet mounting recess 47 is provided at a position directly below 45. The magnet 50 is housed in the magnet mounting recess 47 and is fixed by fixing means such as an adhesive.

FIGS. 4A and 4B show the magnetized state of the magnet 50. FIG. 4A is a perspective view as viewed from above, FIG. 4B is a perspective view as viewed from below, and FIG. It is a side view. As shown in the figure, the magnet 50 is plate-shaped, and forms two sets of magnets in a direction (thickness direction) perpendicular to the surface. That is, the N magnetic pole and the S magnetic pole appear on one surface of the magnet 50.
In the magnet 50 thus configured, a magnetic field is generated on the surface of the magnet 50 from the N pole to the S pole, as shown in FIG. That is, the direction of the magnetic field on the surface of the magnet 50 is substantially perpendicular to the surface just above the N and S magnetic poles.
At an intermediate position between the N and S magnetic poles, the direction is substantially parallel to the surface.

Returning to FIG. 1, the case 60 is made of a metal plate, and is formed by bending a box having an open lower surface. An opening 61 is provided on the upper surface, and two locking claws 63 protrude from a pair of opposed lower end sides.

To assemble the slide type variable resistor, the sliding type object 40 is housed in the case 60, and the mounting substrate 30 is mounted on the lower side of the case 60.
This is performed by bending and fixing the four locking claws 63 inserted into the mounting substrate 30 to the back surface side of the mounting substrate 30. At this time, the lower end side of the case 60 is in contact with the outer peripheral upper surface of the mounting board 30, and the leg portions 43 of the sliding object 40 straddle the magnetic sensor 10, and the lower end sides thereof are on both outer sides of the magnetic sensor 10. It is in contact with the surface of the mounting board 30. At this time, the knob 45 projects from the opening 61.

FIGS. 5 (a) and 5 (b) are schematic side sectional views of the assembled slide type variable resistor cut in orthogonal directions. As shown in the figure, the lower surface of the magnet 50 and the upper surface of the magnetic sensor 10 are plane-parallel and separated by a predetermined short distance (for example, 0.5 mm). The magnet 50 moves on the magnetic sensor 10 by sliding the knob 45 in the direction of the arrow shown in FIG. The slide stroke (stroke from the left end to the right end) in this embodiment is about 1.4 mm.

FIGS. 6 (a) to 6 (c) are operation explanatory diagrams showing the positional relationship between the magnetic sensor 10 and the magnet 50 when the magnet 50 is slid, and the upper side shows a state viewed from the plane. , The lower side shows a state viewed from the side. That is, when the magnet 50 is at the center position, FIG.
(A) As shown in FIG.
Magnetic fields of the same strength in substantially the same direction are applied to 1 to R4, and therefore all have the same resistance value. Thus, in the circuit shown in FIG.
G2 has the same potential (midpoint potential). Output terminal FG1,
The differential pressure of the output of FG2 is amplified by a differential amplifier circuit (not shown). In this case, the differential pressure is 0V.

Next, as shown in FIG. 6B, when the magnet 50 is moved to the left, the two magnetoresistive patterns R1 and R2 on the left side are mainly parallel to the surface of the magnetic sensor 10 and are parallel to the magnetoresistive pattern R1. , R2 are applied in a direction perpendicular to the longitudinal direction. On the other hand, a magnetic field mainly in a direction perpendicular to the surface of the magnetic sensor 10 is applied to the two magnetoresistive patterns R3 and R4 on the right side.

Incidentally, the above-mentioned magnetoresistive patterns R1 to R4
Is made of a ferromagnetic material, and its property is that when a line of magnetic force perpendicular to its longitudinal direction (linear direction) and parallel to the substrate surface is incident (irrespective of the incident direction, the resistance value). In the case of a magnetic field line incident parallel to the longitudinal direction (linear direction) or a magnetic field line incident perpendicularly to the substrate surface, the resistance value is almost the same as when no magnetic field line is incident. .

Therefore, in the state shown in FIG. 6B, the resistance values of the magnetoresistive patterns R1 and R2 are small, while the resistance values of the magnetoresistive patterns R3 and R4 are large (the same as when no magnetic field is applied).

For this reason, in the circuit shown in FIG. 2, the output voltage of the output terminal FG1 is the largest at the midpoint potential, and the output voltage of the output terminal FG2 is the smallest at the midpoint potential.

Next, as shown in FIG. 6 (c), when the magnet 50 is moved rightward, the two left magnetoresistive patterns R
1 and R2, a magnetic field mainly in a direction perpendicular to the surface of the magnetic sensor 10 is applied, while the two magnetoresistive patterns R3 and R4 on the right are mainly applied to the magnetoresistive patterns R3 and R4 parallel to the surface of the magnetic sensor 10. A magnetic field in a direction perpendicular to the longitudinal direction is applied. Therefore, at this time, the resistance values of the magnetoresistive patterns R1 and R2 are large, while the resistance values of the magnetoresistive patterns R3 and R4 are small. Therefore, in the circuit shown in FIG. 2, the output voltage of the output terminal FG1 is the smallest with respect to the midpoint potential, and the output voltage of the output terminal FG2 is the largest with respect to the midpoint potential.

FIG. 7 is a diagram showing the relationship between the displacement position of the magnet 50 and the output voltage. In the figure, points p, q, and r indicate the case where the magnet 50 is at the positions shown in FIGS. 6A, 6B, and 6C, respectively. Then, the differential pressure between FG1 and FG2 (F
G1-FG2) changes substantially linearly when the magnet 50 is moved from the left end q to the right end r. In other words, this corresponds to a linear change in the resistance value, and constitutes a variable resistor.

The above circuit has four magnetoresistive patterns R
Although a full bridge is formed by 1 to R4, a half bridge may be formed by only two magnetoresistive patterns R1 and R4 (or R2 and R3), and a circuit may be formed by only this. In this case, the output voltage is only FG1 (or FG2). However, as shown in FIG. 7, since all outputs change substantially linearly, a variable resistor can be formed.

As described above, in the present invention, the slide type variable resistor is constituted by sliding the magnet relative to the magnetoresistive element provided in the magnetic sensor. If the distance between the south poles is reduced, a variable resistor having a small sliding distance can be formed, and even if the sliding distance is very short, a sliding variable resistor having a sufficient resolution can be formed.

FIG. 8 is a schematic side sectional view (showing a portion corresponding to FIG. 5B) of a sliding variable resistor according to another embodiment of the present invention. This embodiment is different from the above-described embodiment in that the magnetoresistive patterns R1 to R4 are not formed on the upper surface side P of the substrate 11, but are formed on the lower surface side U. 50 is configured to contact the upper surface P of the substrate 11 and slide on the upper surface P. With such a configuration, the distance between the magnet 50 and the magnetoresistive patterns R1 to R4 can be accurately and uniformly set as the thickness distance of the substrate 11, and the accuracy is improved.
Also, the thickness of the sliding variable resistor can be reduced. Also 49
Is a recess for escaping the metal terminal 13 fixed to the substrate 11 so as not to hinder the sliding movement of the sliding object 40.

The present invention is not limited to the above embodiments, and various modifications such as those described below are possible. The material and shape of the magnetoresistive element are not limited to those in the above-described embodiment, but may be any magnetoresistive element whose resistance changes in accordance with the direction of the applied magnetic field. The number of magnetoresistive elements may be four or more or less.

In the above embodiment, the magnet is slid with respect to the magnetic sensor, but the magnetic sensor may be slid with respect to the magnet. In short, it is sufficient that a magnetic field corresponding to the relative sliding position between the two is applied to the magnetoresistive element.

The magnet need not necessarily be attached to a sliding type object, and the magnet itself may be configured to be slidable. When the magnetic sensor is slid in place of the magnet, the magnetic sensor itself may be slid, or an attachment member to which the magnetic sensor is attached may be slid.

In the above embodiment, two sets of N and S magnetic poles are magnetized in the thickness direction of the flat magnetic plate constituting the magnet, so that the direction of the magnetic field is parallel to the surface of the magnet. This is preferable because it can be easily formed at a position close to a vertical one. However, it goes without saying that the shape of the magnet and the state of magnetization on the magnet can be variously modified. That is, for example, the shape of the magnet may be a disk shape (or polygonal shape), or the bar magnet may be U-shaped (or U-shaped, L-shaped).
(A character shape or the like), or may have other shapes. Various changes can also be made to the state of magnetization according to the shape of the magnet.

The substrate 11 and the mounting substrate 30 constituting the magnetic sensor 10 may be integrally formed of the same material.

The mounting substrate 30 is made of a molding resin,
When the mounting substrate 30 is formed, the magnetic sensor 10 may be embedded in the mounting substrate 30.

[0032]

As described in detail above, the present invention has the following excellent effects. Even if the slide distance is short, sufficient resolution can be obtained with high accuracy.

The structure is simple.

Since the magnetoresistive element and the magnet are not in contact,
A waterproof structure can be easily obtained only by coating the magnetoresistive element with a waterproof coat or the like, and the resistor does not increase in size.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a slide type variable resistor to which the present invention is applied.

FIG. 2 is a circuit diagram showing a connection state of each of the magnetic resistance patterns R1 to R4.

FIG. 3 is an exploded perspective view of a sliding mold 40 and a magnet 50 as viewed from below.

4A and 4B are diagrams showing a magnetized state of a magnet 50, wherein FIG. 4A is a perspective view as viewed from above, FIG. 4B is a perspective view as viewed from below, and FIG. 4C is a side view. is there.

FIGS. 5 (a) and 5 (b) are schematic side sectional views of a sliding variable resistor cut in orthogonal directions.

6 (a) to 6 (c) are operation explanatory diagrams showing the positional relationship between the magnetic sensor 10 and the magnet 50 when the magnet 50 is slid.

FIG. 7 is a diagram showing a relationship between a displacement position of a magnet 50 and an output voltage.

FIG. 8 is a schematic side sectional view of a slide type variable resistor according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Magnetic sensor R1, R2, R3, R4 Magnetic resistance pattern (magnetic resistance element) 30 Mounting board 40 Sliding object 50 Magnet 60 Case

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Satoshi Kuwahara 335 Karijuku, Nakahara-ku, Kawasaki-shi, Kanagawa F-term in Teikoku Communication Industry Co., Ltd. (reference) 5E030 BA30 CA04 CB03 HA04

Claims (2)

[Claims] 1. A magnetic sensor provided with a magnetoresistive element whose resistance value changes in accordance with the direction of a magnetic field to be applied, and a slidable movement with respect to the magnetic sensor and a slidable position with respect to the magnetoresistive element in accordance with the sliding position. And a magnet that changes the direction of a magnetic field to be applied, wherein the resistance value of the magnetoresistive element is changed by sliding the magnet relative to the magnetic sensor. . 2. The magnet according to claim 1, wherein the magnet has a plate shape, and an N magnetic pole and an S magnetic pole are provided on one surface of the magnet so that a magnetic field direction is substantially right above the N and S magnetic poles with respect to the magnet surface. Vertically,
At the intermediate position between the N and S magnetic poles, it is configured to be substantially parallel,
2. The sliding variable resistor according to claim 1, wherein the direction of the magnetic field applied to the magnetoresistive element is changed by sliding a magnet relative to the magnetoresistive element.