JPH10232141A - Method for magnetizing magnetic body and magnetic potentiometer using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for magnetizing a magnetic body that has improved linearity within a specific angle range and can obtain large output and a magnetic potentiometer using the magnetic body. SOLUTION: A ferromagnetic body 20 that is in disk shape while being saturated and magnetized and has a magnetic pole with at least four poles in terms of top view and a magnetic detection element (Hall element) for detecting the magnetic force of the normal constituent of the ferromagnetic body 20 while being arranged on the peripheral side surface of the ferromagnetic body 20 are provided. When a distance between magnetic poles N and S where the disk of the ferromagnetic body 20 is adjacent is set to A, a distance between a cross point C between a line L1 for connecting a center O of the ferromagnetic body 20 from a magnetization center (hole part) and a line L2 for connecting the magnetic poles N and S being adjacent to the line L1 and the magnetization center (hole part) is set to B, the magnetization center (hole part) of the magnetic pole is set to a position (A is smaller than the radius of the ferromagnetic body 20) for satisfying B/A=0.5-1.0 away from a disk side surface in the magnetized ferromagnetic body 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of magnetizing a magnetic material for magnetizing four or more magnetic poles and a magnetic potentiometer.

[0002]

2. Description of the Related Art A conventional magnetic potentiometer has a Hall element for detecting a magnetic field (magnetic flux and magnetic force) of only a normal component on a side surface of a disk-shaped ferromagnetic material saturated in an air-core coil, and a semiconductor magnetoresistive element. There is known a type in which a magnetic detection element such as an effect element is provided and the output of the magnetic detection element is extracted.

FIG. 6 is an explanatory view showing the concept of a general magnetic potentiometer, and FIG. 7 is an explanatory view showing the principle of the Hall element shown in FIG. In FIG. 6, reference numeral 1 denotes a rotating body rotatably supported by a frame (not shown). And a protruding operation shaft 3.
This ferromagnetic material 2 is formed by an air-core coil as described later.
A set of N and S poles is magnetized, and a Hall element 4 for detecting magnetic flux from the N and S poles of the rotating ferromagnetic body 2 is provided. The Hall element 4 detects only the magnetic flux of the normal component of the ferromagnetic material 2, and FIG. 7 shows a general circuit diagram of the Hall element 4. In FIG.
Reference numeral 6 denotes a power supply, and 6 denotes a voltmeter for detecting a Hall voltage generated by the Hall element 4 detecting a magnetic flux of a normal component.

FIG. 8 is a circuit diagram of a general magnetic potentiometer, in which 4 is a Hall element, 7 is an amplifier,
8 is a gain adjustment unit, 9 is an amplifier, and 10 is a temperature compensation unit. The voltage Vcc is applied to the Hall element 4. The Hall voltage generated in the Hall element 4 is amplified, gain-adjusted, and temperature-compensated through a circuit such as an amplifier 7 to obtain Vo.
ut is output.

Next, a method of magnetizing a ferromagnetic material will be described. FIG. 9 is an explanatory diagram showing the magnetization of the ferromagnetic material by the coreless coil, and FIG. 10 is an explanatory diagram showing the magnetized state of the ferromagnetic material by the method of FIG. In these figures, 2
Is a disk-shaped ferromagnetic material having a through hole in the center, 11 is an air-core coil for magnetization, 12 is a power supply connected to the air-core coil 11, and as shown in FIG. When the ferromagnetic material 2 is housed in the coil 11 and a direct current is applied, the air-core coil 1
1, a magnetic flux φ is generated, and as shown in FIG. 10, N and S poles are magnetized on the outer peripheral surface of the ferromagnetic material 2 at an angle of 180 °. When the ferromagnetic material 2 is saturated and magnetized in such an air-core coil 11, the magnetic material 2 is magnetized substantially in parallel as a whole, so that the normal component of the magnetic field emitted from the ferromagnetic material 2 is reduced. Except for around the inflection point, it increases linearly. That is, since the ferromagnetic material 2 is saturated, the ferromagnetic material 2
Is not changed at any position, but when the ferromagnetic material 2 is rotated, only the normal component of the ferromagnetic material 2 to the Hall element 4 changes.

[0006]

In the prior art, the N pole and the S pole are placed on the ferromagnetic material 2 at positions 180 degrees opposite to each other.
Only the poles can be magnetized, and the output peaks at the positions of the N and S poles.
In the case of a type with a small effective rotation angle, it is necessary to use a magnet with a large energy product in order to obtain the same output as the conventional one. (Since the output peak is determined only by the saturation magnetization density of the magnetic material, ), It is necessary to change the material of the ferromagnetic material 2, but this increases the cost.
In particular, when the effective rotation angle is reduced, that is, when used in a narrow range, it is not suitable for increasing the output in that range.

There is a method of magnetizing the ferromagnetic material 2 by so-called yoke magnetization. In this method, magnetic poles can be formed at a predetermined pitch, and the magnetic material can be saturated even in a narrow range. An output corresponding to the magnetization density can be obtained. FIG. 11 is an explanatory view for magnetizing eight poles, 13 is a yoke having a storage portion for storing a ferromagnetic material,
Reference numeral 14 denotes a hole that penetrates electric wires (coils) 15 formed at equal intervals in the storage portion of the yoke 13. One electric wire 15 is fitted around each of the holes 14 and 14. Each of the holes 14, 14 communicates with the storage section in a slit shape. When a direct current is applied to the electric wire 15, a magnetic flux is generated as shown in FIG. 11, and the magnetic flux magnetizes the N and S poles of the ferromagnetic material 2. Further, although not shown, the N and S poles are also magnetized by the magnetic flux of the electric wire 15 in the other holes 14, so that the N and S poles are alternately magnetized on the peripheral surface of the ferromagnetic material 2 by eight poles. You. However, in the conventional yoke magnetizing method, the ferromagnetic material (magnetized material) 2
The magnet 15 is arranged in the hole 14 of the yoke 13 so that the electric wire 15 is in contact with the magnetic field, and is magnetized. Therefore, a magnetic field centering on the peripheral surface of the ferromagnetic body 2 (see FIG. 11 or FIG. 5A described later) Is formed, the characteristics of the Hall voltage Vout and the operation angle of the rotating shaft by the magnetic potentiometer using the same have poor linearity (linearity), and the rotation angle cannot be detected accurately.

An object of the present invention is to provide a method of magnetizing a magnetic material which is excellent in linearity in a predetermined angle range and can obtain a high output, and a magnetic potentiometer using the magnetic material. is there.

[0009]

The object of the present invention is to provide a ferromagnetic material which is provided with four or more magnetic poles in plan view in the shape of a saturated magnetized disk, and which is disposed on a peripheral side surface of the ferromagnetic material. A magnetic detecting element for detecting the magnetic force of the normal component of the ferromagnetic material,
A is the distance between adjacent magnetic poles of the ferromagnetic disk,
When the distance between the magnetic center and the intersection of the line connecting the center of the ferromagnetic material from the magnetic center and the line connecting the adjacent magnetic poles is B, the magnetic center of the magnetic pole is defined as B / A = 0.5 to Position satisfying 1.0 (however, A is smaller than the radius of the ferromagnetic material)
The first means is a ferromagnetic material which is magnetized while being set apart from the side surface of the disk. In the first means, in the first means, the other magnetic center adjacent to the magnetic center of the magnetic pole magnetized away from the disk side surface is a ferromagnetic material magnetized in contact with the disk side surface. It can be solved by means. The problem is that a disk-shaped ferromagnetic material is housed in a yoke in which a coil serving as a magnetization center is disposed, the distance between adjacent magnetic poles of the disk of the ferromagnetic material is A, When the distance between the intersection of the line connecting the center of the body and the line connecting the adjacent magnetic poles and the center of magnetization is B, the center of magnetization of the magnetic pole satisfies B / A = 0.5 to 1.0. This can be solved by the third means in which the magnet is set at a position (where A is smaller than the radius of the ferromagnetic material) away from the side surface of the disk of the ferromagnetic material. According to a third aspect of the present invention, in the third means, the yoke has a tapered surface that extends from the center of magnetization disposed away from the disk side surface of the ferromagnetic material toward the disk peripheral surface of the ferromagnetic material. 4 can be solved. According to a third aspect, in the third means, the other magnetization center adjacent to the magnetization center of the magnetic pole magnetized away from the disk side surface is magnetized in contact with the disk side surface.
This can be solved by the following means.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing a ferromagnetic material according to an embodiment of a magnetic potentiometer according to the present invention, and FIGS. 2 (a), (b) and (c) are a plan view and a front view showing a yoke used for magnetization. FIG. 3 is an explanatory diagram showing the relationship between the ferromagnetic material and the electric wire, FIG. 4 is a diagram showing the characteristics of the linearity and the distance ratio in FIG. 3, and FIGS. () Is an explanatory diagram showing a state of magnetic flux when magnetizing is performed in a state where the electric wire is in contact with the ferromagnetic material and in a state where the electric wire is separated from the ferromagnetic material. The same parts as those in the conventional example are denoted by the same reference numerals, and detailed description will be omitted.

FIG. 1 shows a ferromagnetic material that can cope with a case where the effective rotation angle of the magnetic potentiometer is reduced. The ferromagnetic body 20 has a disk shape and a through hole is formed at the center thereof. The ferromagnetic body 20 is magnetized in four poles, and as shown in FIG. 1, a magnetizing range (for example, an effective rotation range θ1) of two of N poles and S poles (lower side in the figure) of the four poles. Is set to be narrow, and the magnetizing range (for example, other than the effective rotation range θ1) of the other two N and S poles (upper side in the figure) is set to be narrow.

Next, a method of yoke magnetizing the ferromagnetic material 20 shown in FIG. 1 will be described with reference to FIGS. In the figure, 21 is a yoke, and the yoke 21 is
A storage portion 22 is formed in the inner peripheral edge of the storage portion 22, and four holes 23, 24, 25, and 26 penetrating the electric wire (coil) 15 are formed as shown in FIG. Have been. The arrangement of the holes 23, 24, 25, 26 is such that the holes 24, 25 are respectively set at an angle of 130 ° from the hole 23 located above in FIG. The holes 26 are arranged at an angle of 180 °. θ1 is an effective rotation range, for example, θ1 = 40 °. Each hole 23, 24, 25, 26 has one electric wire 15
It is fitted around.

The hole 26 is set apart from the side surface of the disk of the ferromagnetic material 20 housed in the yoke 21 in the following relationship. That is, as shown in FIG. 3, the distance between the adjacent magnetic poles N and S of the disk of the ferromagnetic material 20 is A, and a line connecting the electric wire (magnetization center) 15 of the hole 26 to the center O of the ferromagnetic material 20. Assuming that the distance between the intersection C of L1 and the line L2 connecting the adjacent magnetic poles N and S and the electric wire (magnetization center) 15 of the hole 26 is B, the magnetization center of the magnetic pole (hole 26) is represented by B /
The ferromagnetic material 20 is set at a position that satisfies A = 0.5 to 1.0 (where A is smaller than the radius of the ferromagnetic material) and is separated from the side surface of the disk of the ferromagnetic material 20. Further, tapered surfaces 27, 27 extending from the center of magnetization (hole 26) toward the disk peripheral surface of the ferromagnetic body 20 (storage portion 22) are formed.

Here, B / A = 0.5 to 1.0 will be described. FIG. 4 shows the characteristics of the linearity and the distance ratio shown in FIG. 3. In FIG. 4, the horizontal axis represents the distance ratio (B /
A), the vertical axis is linearity (%). By the way, since it is practically necessary that the linearity is within 2%, it is desirable that B / A is 0.5 or more from FIG. If the magnetization center (hole portion 26) is too far from the ferromagnetic body 20 (that is, if B is too large), a large current must be passed through the electric wire to magnetize the ferromagnetic body 20. Therefore, it is desirable that B / A is 1.0 or less. Therefore, B / A is set to 0.5 to 1.0.

The holes 23, 24 and 25 are formed as shown in FIG.
As shown in FIG. 5A, the magnetic flux generated by the electric wire 15 inserted into the holes 23, 24, and 25 is generated as shown in FIG. The magnetic body 20 is magnetized as shown in FIG. On the other hand, as shown in FIG. 2A, the hole 26 communicates with the storage portion 22 at a communicating portion formed by slits and tapered surfaces 27, 27. The magnetic flux generated by the electric wire 15 inserted into the hole 26 is As shown in FIG. 5B, the magnetic flux is generated and magnetizes the ferromagnetic material 20. That is, since the magnetization center is far from the ferromagnetic material 20, a substantially parallel magnetic field can be formed in the ferromagnetic material 20. Therefore, the present invention provides a method of magnetizing a magnetic body which is excellent in linearity in a predetermined angle range and can obtain high output.

Although the above embodiment has been described with four poles, the number of poles may be more than four.

In the above-described embodiment, the ferromagnetic body 20 is provided with four or more magnetic poles in plan view in the shape of a saturated magnetized disk, and the ferromagnetic body 20 is disposed on the peripheral side surface of the ferromagnetic body 20. And a magnetic detecting element (Hall element 4) for detecting the magnetic force of the normal component of the ferromagnetic body 20, and as shown in FIG. 3, the distance between the adjacent magnetic poles N and S of the disk of the ferromagnetic body 20. Is defined as A, and an intersection C between a line L1 connecting the center O of the ferromagnetic body 20 from the magnetization center (hole 26) to a line L2 connecting the adjacent magnetic poles N and S, and the magnetization center (hole 26). When the distance is B, the magnetization center of the magnetic pole (hole 26) is set to B / A = 0.5 to
Since the ferromagnetic material 20 is set at a position satisfying 1.0 (where A is smaller than the radius of the ferromagnetic material 20) and is magnetized at a distance from the side surface of the disk, further, it is further separated from the side surface of the disk. The other magnetization centers (holes 24 and 25) adjacent to the magnetization center (holes 26) of the magnetic pole to be magnetized are the ferromagnetic material 20 that is magnetized in contact with the disk side surface. Since a substantially parallel magnetic field is formed, a magnetic potentiometer having excellent linearity in a predetermined angle range and capable of obtaining high output is provided.

In the above embodiment, the disk-shaped ferromagnetic material 20 is housed in the yoke in which the coil serving as the magnetization center (hole 26) is disposed, and the disk of the ferromagnetic material 20 is The distance between the adjacent magnetic poles N and S is A, and an intersection C between a line L1 connecting the center of the magnetization (hole 26) to the center of the ferromagnetic body 20 and a line L2 connecting the adjacent magnetic poles N and S; Assuming that the distance from the center (hole 26) is B, the magnetization center of the magnetic pole (hole 26) is positioned at a position satisfying B / A = 0.5 to 1.0 (where A is the ferromagnetic material 20). (Smaller than the radius of the ferromagnetic material 20) to be magnetized at a distance from the disk side surface of the ferromagnetic material 20, and the yoke has a magnetization center (hole portion 26) disposed at a distance from the disk side surface of the ferromagnetic material 20. To form a tapered surface 27, 27, which widens toward the disk peripheral surface of the ferromagnetic material 20. Other magnetization center adjacent to the magnetization center (hole portion 26) of magnetic poles magnetized away from the board side (hole 2
4, 25) is magnetized in contact with the side of the disk,
Since a substantially parallel magnetic field can be formed in the ferromagnetic body 20, a method of magnetizing the magnetic body 20 that is excellent in linearity in a predetermined angle range and can obtain high output is provided.

[0019]

According to the first and second aspects of the present invention, since a substantially parallel magnetic field is formed in the ferromagnetic material by yoke magnetization, excellent linearity and a high output are obtained within a predetermined angle range. To provide a magnetic potentiometer. According to the third, fourth, and fifth aspects of the present invention, since a substantially parallel magnetic field is formed in the ferromagnetic material by yoke magnetization, excellent linearity and a high output can be obtained within a predetermined angle range. Provided is a method for magnetizing a magnetic material.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a ferromagnetic material of one embodiment of a magnetic potentiometer according to the present invention.

FIGS. 2 (a), (b), and (c) are a plan view and a front view showing a yoke used for magnetization, and an enlarged view of a wire insertion hole.

FIG. 3 is an explanatory diagram showing a relationship between a ferromagnetic material and an electric wire.

FIG. 4 is a diagram showing characteristics of linearity and a distance ratio in FIG. 3;

FIGS. 5A and 5B are explanatory diagrams showing states of magnetic flux when magnetizing is performed in a state where an electric wire is in contact with a ferromagnetic material and in a state where the electric wire is separated from the ferromagnetic material.

FIG. 6 is an explanatory view showing the concept of a general magnetic potentiometer.

FIG. 7 is an explanatory view showing the principle of the Hall element in FIG. 6;

FIG. 8 is a circuit diagram of a general magnetic potentiometer.

FIG. 9 is an explanatory view showing magnetization of a ferromagnetic material by a coreless coil.

FIG. 10 is an explanatory diagram showing a magnetized state of a ferromagnetic material according to the method of FIG. 9;

FIG. 11 is an explanatory diagram for eight-pole magnetization.

[Explanation of symbols]

 Reference Signs List 4 Hall element 20 Ferromagnetic material 24, 25 Hole 26 Hole 27 Tapered surface A Distance B Distance C Intersection L1 Connecting line L2 Connecting line N, S Magnetic pole O Center of ferromagnetic material 20

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mitsumasa Inoue 1-7 Yukitani Otsuka-cho, Ota-ku, Tokyo Alps Electric Co., Ltd.

Claims (5)

[Claims] 1. A disk having a saturation magnetization and having a shape of 4
A ferromagnetic body provided with more than two magnetic poles, and a magnetic detection element disposed on a peripheral side surface of the ferromagnetic body and detecting a magnetic force of a normal component of the ferromagnetic body. Let A be the distance between adjacent magnetic poles,
When the distance between the magnetic center and the intersection of the line connecting the center of the ferromagnetic material from the magnetic center and the line connecting the adjacent magnetic poles is B, the magnetic center of the magnetic pole is defined as B / A = 0.5 to Position satisfying 1.0 (however, A is smaller than the radius of the ferromagnetic material)
A magnetic potentiometer characterized in that it is a ferromagnetic material which is magnetized by being set apart from the side of the disk. 2. The magnetic recording medium according to claim 1, wherein the other magnetic center adjacent to the magnetic center of the magnetic pole magnetized away from the disk side surface is a ferromagnetic material magnetized in contact with the disk side surface. Characteristic magnetic potentiometer. 3. A disk-shaped ferromagnetic material is housed in a yoke in which a coil serving as a magnetization center is disposed, and a distance between adjacent magnetic poles of the disk of the ferromagnetic material is A, and the distance from the magnetization center is strong. When the distance between the intersection of the line connecting the center of the magnetic body and the line connecting the adjacent magnetic poles and the center of magnetization is B, the magnetization center of the magnetic pole is represented by B / A = 0.5 to 1.0. A method of magnetizing a magnetic material, comprising: setting a magnet at a satisfactory position (where A is smaller than the radius of the ferromagnetic material) away from the side surface of the disk of the ferromagnetic material. 4. The yoke according to claim 3, wherein the yoke has a tapered surface extending from the center of magnetization of the ferromagnetic material disposed away from the disk side surface toward the disk peripheral surface of the ferromagnetic material. A method for magnetizing a magnetic material, comprising: 5. The magnetic field according to claim 3, wherein another magnetic center adjacent to the magnetic center of the magnetic pole magnetized away from the disk side surface is magnetized in contact with the disk side surface. How to magnetize the body.