JP2024078836A - Easy magnetization direction inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easy magnetization direction inspection device that can easily inspect an easy magnetization direction of a magnetic material before magnetization.

SOLUTION: A device that inspects an easy magnetization direction of a magnetic material before magnetization includes: a magnetic field generator that generates a uniform magnetic field in a specified direction; a holder that is placed in the magnetic field generated by the magnetic field generator and holds the magnetic material; a rotation mechanism that supports the holder such that the holder can rotate in two or three dimensions; and rotation angle measuring means that measures the rotation angle of the holder relative to the direction of the magnetic field.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to an easy magnetization direction inspection device that inspects the easy magnetization direction of magnetic material before magnetization.

For example, in the magnetic circuits of linear motors and undulators, multiple magnets are arranged in a specific direction, and among these multiple magnets, there are magnets whose magnetization direction is oriented obliquely relative to the magnet arrangement direction (for example, Patent Documents 1 and 2).

Currently, such obliquely oriented magnets are formed by cutting out unmagnetized magnetic material at an angle to the easy magnetization direction, and then magnetizing the cut-out magnetic material along the easy magnetization direction. This is because orienting the easy magnetization direction at an angle from the beginning requires manufacturing using a mold, which is costly, but it is not possible to tell from appearance whether the easy magnetization direction of the cut-out magnetic material is correctly oriented in the desired direction.

In addition, when magnetizing with a magnetizing device (magnetizer), if the direction of easy magnetization is misaligned with the magnetization direction, the magnetic material may rotate inside the magnetizing device, leading to malfunctions or accidents, so it is necessary to check the direction of easy magnetization of the magnetic material before magnetization.

JP 2021-100315 A JP 2012-160408 A

The objective of the present invention is to provide an easy magnetization direction inspection device that can easily inspect the easy magnetization direction of magnetic material before it is magnetized.

The easy magnetization direction inspection device of the present invention is a device for inspecting the easy magnetization direction of a magnetic material before magnetization,
A magnetic field generating device that generates a uniform magnetic field in a predetermined direction;
a holder that is disposed in the magnetic field generated by the magnetic field generating device and holds the magnetic material;
A rotation mechanism that supports the holder so as to be rotatable in two or three dimensions;
A rotation angle measuring means is provided for measuring a rotation angle of the holder relative to the direction of the magnetic field.

Even before magnetization, when a magnetic material is placed in a magnetic field, a force acts on the magnetic material that tends to make the easy magnetization direction move in the same direction as the magnetic field, so the holder rotates so that the easy magnetization direction of the magnetic material it holds matches the direction of the magnetic field. Therefore, the easy magnetization direction of the magnetic material before magnetization can be easily inspected based on the rotation angle of the holder measured by the rotation angle measuring means.

In the easy magnetization direction inspection device of the present invention, the holder may be made of a non-magnetic material.

With this configuration, the holder is not affected by the magnetic field, so the easy magnetization direction of the magnetic material can be accurately inspected.

In the easy magnetization direction inspection device of the present invention, the magnetic field generating device may be a pair of ferrite magnets with opposite poles facing each other, and the holder may be arranged on a straight line connecting the centers of the facing surfaces of the pair of ferrite magnets.

With this configuration, the holder is placed in a uniform magnetic field generated between a pair of ferrite magnets, allowing the easy magnetization direction of the magnetic material to be accurately inspected.

In the easy magnetization direction inspection device of the present invention, a frame having a first plate-shaped member and a pair of second plate-shaped members arranged at both ends of the first plate-shaped member in a direction perpendicular to one plane of the first plate-shaped member is further provided,
The pair of ferrite magnets are fixed to the pair of second plate-like members, respectively,
The rotation mechanism may be configured to include a rotating shaft having one end connected to the holder, and a bearing arranged on one plane of the first plate-shaped member and rotatably supporting the other end of the rotating shaft.

With this configuration, the holder can be rotated smoothly, allowing the easy magnetization direction of the magnetic material to be accurately inspected.

In the easy magnetization direction inspection device of the present invention, the frame may be made of non-magnetic stainless steel.

With this configuration, the frame does not form a magnetic circuit with the pair of ferrite magnets, and the frame does not adversely affect the magnetic field between the pair of ferrite magnets, so the easy magnetization direction of the magnetic material can be accurately inspected.

In the easy magnetization direction inspection device of the present invention, the rotation angle measuring means may be configured to include a pointer fixed to the holder and a display plate for measuring the rotation angle of the pointer.

This configuration makes it easy to measure the rotation angle of the holder.

FIG. 1 is a perspective view of an easy magnetization direction inspection device according to an embodiment; FIG. 2 is a plan view of the easy magnetization direction inspection device according to the embodiment; A plan view showing an example of a magnetic material FIG. 1 is a plan view for explaining a method for inspecting the easy magnetization direction of a magnetic material; FIG. 13 is a plan view of an easy magnetization direction inspection device according to another embodiment;

Below, an example of an embodiment of the easy magnetization direction inspection device of the present invention will be described with reference to the drawings.

Figure 1 is a perspective view showing an example of an easy magnetization direction inspection device. Figure 2 is a plan view of the easy magnetization direction inspection device of Figure 1. Figure 3 is a plan view showing an example of a magnetic material.

In this specification, a magnetic material is a sintered body obtained by finely pulverizing a magnetic alloy, which is the raw material for a magnet, forming the resulting alloy powder (anisotropic magnetic powder) while aligning it in a magnetic field, and sintering and heat treating the resulting compact. In the magnetic material, the orientation direction is the easy magnetization direction. The magnetic material becomes an anisotropic magnet when magnetized along the easy magnetization direction.

The magnetic material 9 of this embodiment is formed in a rectangular plate shape. In FIG. 3, the arrow 9a on the magnetic material 9 indicates the easy magnetization direction, but in reality, the easy magnetization direction 9a cannot be distinguished by appearance. The easy magnetization direction 9a of this embodiment is oriented in a direction inclined at an angle α with respect to the center line 9b of the magnetic material 9. Hereinafter, α is also referred to as the orientation angle.

The easy magnetization direction inspection device 1 is a device for inspecting the easy magnetization direction 9a of the magnetic material 9 before magnetization. As shown in Figs. 1 and 2, the easy magnetization direction inspection device 1 includes a magnetic field generating device 2 that generates a uniform magnetic field in a predetermined direction, a holder 3 that is placed in the magnetic field generated by the magnetic field generating device 2 and holds the magnetic material 9, a rotation mechanism 4 that supports the holder 3 so that it can rotate two or three-dimensionally, and a rotation angle measuring means 5 (not shown in Fig. 1) that measures the rotation angle of the holder 3 with respect to the direction of the magnetic field.

The magnetic field generator 2 may be a permanent magnet such as a ferrite magnet or a rare earth magnet, or may be an electromagnet, for example, a Helmholtz coil type electromagnet. The magnetic field generator 2 of this embodiment is a pair of ferrite magnets 21, 22 facing each other at a distance. The pair of ferrite magnets 21, 22 are arranged so that the opposite poles face each other, and a uniform (uniform) magnetic field is generated in the direction from the ferrite magnet 21 to the ferrite magnet 22 between the facing surfaces 21a, 22a of the pair of ferrite magnets 21, 22. The facing distance, the size of the ferrite magnets 21, 22, their shape, and the strength of the magnetic field are appropriately set depending on the size of the magnetic material 9 to be inspected, etc. In addition, magnetic pole pieces can be placed on the facing surfaces of the ferrite magnets 21, 22 as necessary. In this case, by configuring the magnetic field generator 2 with an electromagnet, the strength of the magnetic field can be easily adjusted. If the magnetic field is too weak, the holder 3 will not rotate, and if it is too strong, the magnetic material 9 will be slightly magnetized, which may cause residual magnetism or make magnetization difficult in the subsequent magnetization process, thereby adversely affecting the magnetic material 9. The strength of the magnetic field is, for example, 10 to 80 mT.

The pair of ferrite magnets 21, 22 may be fixed to a frame 6 as shown in FIG. 1. The frame 6 has a first plate-shaped member 6a and a pair of second plate-shaped members 6b, 6c arranged at both ends of the first plate-shaped member 6a in a direction perpendicular to one plane of the first plate-shaped member 6a. In the embodiment shown in FIG. 1, the frame 6 is a roughly U-shaped member having a first plate-shaped member 6a extending horizontally and a pair of second plate-shaped members 6b, 6c extending upward from both ends of the first plate-shaped member 6a. The pair of ferrite magnets 21, 22 are fixed to the pair of second plate-shaped members 6b, 6c, respectively. In the embodiment shown in FIG. 1, for example, they are fixed to the upper parts of the pair of second plate-shaped members 6b, 6c, respectively.

The frame 6 is made of a non-magnetic material. For example, non-magnetic stainless steel such as SUS304 can be used as the material of the frame 6. By making the frame 6 out of a non-magnetic material, the frame 6 does not form a magnetic circuit with the pair of ferrite magnets 21, 22, and therefore the frame 6 does not adversely affect the magnetic field between the pair of ferrite magnets 21, 22.

The holder 3 is disposed between the pair of ferrite magnets 21, 22. The holder 3 is preferably disposed on a straight line connecting the centers of the opposing faces 21a, 22a of the pair of ferrite magnets 21, 22.

The holder 3 has a recess 3a for accommodating the magnetic material 9. In this embodiment, the magnetic material 9 is a rectangular plate, and the recess 3a is a rectangular parallelepiped space with a bottom and side surfaces that are slightly larger than the magnetic material 9. The recess 3a is formed approximately in the center of the holder 3.

The holder 3 is preferably made of a non-magnetic material. This means that the holder 3 is not affected by the magnetic field generated by the magnetic field generating device 2, and therefore does not adversely affect the inspection. Examples of non-magnetic materials include resin and non-magnetic metal, and preferably resin is used.

The rotation mechanism 4 includes a rotating shaft 41, one end of which is connected to the holder 3, and a bearing 42, which is disposed on one plane of the first plate-shaped member 6a and rotatably supports the other end of the rotating shaft 41. In the embodiment shown in FIG. 1, the rotation mechanism 4 includes a rotating shaft 41 that extends in the vertical direction and has an upper end connected to the holder 3, and a bearing 42, which is disposed on the first plate-shaped member 6a of the frame 6 and rotatably supports the lower end of the rotating shaft 41.

The upper end of the rotating shaft 41 is connected to approximately the center of the lower surface of the holder 3. The rotating shaft 41 is preferably made of a non-magnetic material. This means that the rotating shaft 41 is not affected by the magnetic field generated by the magnetic field generating device 2, and therefore does not adversely affect the inspection. Examples of non-magnetic materials include resin and non-magnetic metal, and preferably resin is used.

In the embodiment shown in FIG. 1, the bearing 42 is embedded in the upper surface of the first plate-shaped member 6a and rotatably supports the lower end of the rotating shaft 41. This allows the holder 3 to rotate together with the rotating shaft 41 in a horizontal plane. The bearing 42 is, for example, a thrust bearing.

The rotation angle measuring means 5 measures the rotation angle θ of the holder 3 relative to the direction of the magnetic field generated by the magnetic field generating device 2. Although not particularly limited, the rotation angle measuring means 5 is, for example, a protractor that measures the rotation angle θ of the center line 3b of the holder 3 relative to the direction of the magnetic field.

Figure 4 is a plan view illustrating a method for inspecting the easy magnetization direction 9a of a magnetic material 9 using an easy magnetization direction inspection device 1.

Even before magnetization, when the magnetic material 9 is placed in a magnetic field, a slight force acts to move the easy magnetization direction 9a in the same direction as the magnetic field. The easy magnetization direction inspection device 1 of the present invention utilizes this phenomenon. When a rotatable holder 3 is placed in the magnetic field generated by the magnetic field generator 2 and the magnetic material 9 is placed in the recess 3a of the holder 3, the holder 3 rotates so that the easy magnetization direction 9a of the magnetic material 9 coincides with the direction of the magnetic field generated by the magnetic field generator 2 (indicated by the arrow extending in the left-right direction in Figure 4). This makes it possible to inspect the easy magnetization direction 9a of the magnetic material 9 by the rotation angle θ of the holder 3 relative to the direction of the magnetic field generated by the magnetic field generator 2.

For example, as shown in FIG. 4, when the rotation angle of the holder 3 measured by the protractor 5 is θ, it can be seen that the easy magnetization direction 9a of the magnetic material 9 is inclined at an angle θ with respect to the center line 9b of the magnetic material 9. In other words, it can be seen that the orientation angle α of the easy magnetization direction 9a shown in FIG. 3 is θ.

In view of the above, the easy magnetization direction inspection device 1 is a device for inspecting the easy magnetization direction 9a of the magnetic material 9 before magnetization, and is preferably configured to include a magnetic field generating device 2 that generates a uniform magnetic field in a predetermined direction, a holder 3 that is placed in the magnetic field generated by the magnetic field generating device 2 and holds the magnetic material 9, a rotation mechanism 4 that supports the holder 3 so that it can rotate two or three-dimensionally, and a rotation angle measuring means 5 (a protractor in this embodiment) that measures the rotation angle θ of the holder 3 relative to the direction of the magnetic field.

With this configuration, the easy magnetization direction 9a of the magnetic material 9 before magnetization can be easily inspected based on the rotation angle θ of the holder 3 measured by the rotation angle measuring means 5.

The easy magnetization direction inspection device 1 is not limited to the configuration of the above-mentioned embodiment, nor is it limited to the above-mentioned action and effect. Furthermore, it goes without saying that various modifications can be made to the easy magnetization direction inspection device 1 within the scope of the gist of the present invention. For example, the configurations and methods of the above-mentioned embodiments may be arbitrarily adopted and combined, and further, it goes without saying that one or more of the configurations and methods of the various modified examples described below may be arbitrarily selected and adopted in the configurations and methods of the above-mentioned embodiments.

(1) In the easy magnetization direction inspection device 1 according to the above embodiment, the rotation mechanism 4 is configured to include a rotation shaft 41 that extends in the vertical direction and whose upper end is connected to the holder 3, and a bearing 42 that is arranged on the first plate-shaped member 6a of the frame 6 and rotatably supports the lower end of the rotation shaft 41. However, the easy magnetization direction inspection device 1 is not limited to this configuration. The rotation mechanism 4 may be configured to be a spherical bearing that rotatably supports the holder 3 in three dimensions. The holder 3 is housed in the spherical bearing. The spherical bearing is fixed, for example, to the upper end of a support shaft that extends upward from the first plate-shaped member 6a of the frame 6.

(2) In the easy magnetization direction inspection device 1 according to the above embodiment, the rotation angle measuring means 5 is a protractor that measures the rotation angle θ of the center line 3b of the holder 3 relative to the magnetic field direction. However, the easy magnetization direction inspection device 1 is not limited to this configuration. The rotation angle measuring means 5 may be, for example, an image measuring means or a laser measuring means. The image measuring means, for example, photographs the easy magnetization direction inspection device 1 from above and measures the rotation angle θ of the holder 3 from the photographed image. The laser measuring means, for example, irradiates a laser onto a mirror attached to the outer surface of the holder 3 and measures the rotation angle θ of the holder 3 from the reflected light of the laser.

(3) As shown in FIG. 5, the rotation angle measuring means 5 may be configured to include a pointer 51 fixed to the holder 3 and a display plate 52 for measuring the rotation angle of the pointer 51. The rotation angle measuring means 5 shown in FIG. 5 can not only measure the rotation angle of the holder 3, but also inspect the quality of the magnetic material 9. Specifically, when the pointer 51 points to "OK" on the display plate 52, it can be determined that the magnetic material 9 is a non-defective product in which the easy magnetization direction 9a of the magnetic material 9 is oriented at an angle within the desired range, and when the pointer 51 points to "NG" on the display plate 52, it can be determined that the magnetic material 9 is a defective product in which the easy magnetization direction 9a of the magnetic material 9 is oriented at an angle outside the desired range.

(4) In the easy magnetization direction inspection device 1 according to the above embodiment, the magnetic material 9 in which the easy magnetization direction 9a is oriented diagonally relative to the center line 9b is inspected, but this is not limited to the above. The easy magnetization direction inspection device 1 can also inspect a magnetic material 9 in which the easy magnetization direction 9a is in the same direction as the center line 9b. In this case, the rotation angle θ shown in FIG. 4 is zero. The easy magnetization direction inspection device 1 can also inspect a magnetic material 9 in which the easy magnetization direction 9a is perpendicular to the center line 9b. In this case, the rotation angle θ shown in FIG. 4 is 90 degrees.

1...Easy magnetization direction inspection device, 2...Magnetic field generator, 3...Holder, 3a...Recess, 3b...Center line of holder, 4...Rotation mechanism, 5...Rotation angle measurement means, 6...Frame, 6a...First plate-shaped member, 6b...Second plate-shaped member, 6c...Second plate-shaped member, 9...Magnetic material, 9a...Easy magnetization direction, 9b...Center line of magnetic material, 21...Ferrite magnet, 22...Ferrite magnet, 41...Rotating shaft, 42...Bearing, 51...Indicator, 52...Display board, α...Orientation angle, θ...Rotation angle

Claims (6)

An apparatus for inspecting the direction of easy magnetization of a magnetic material before magnetization, comprising:
A magnetic field generating device that generates a uniform magnetic field in a predetermined direction;
a holder that is disposed in the magnetic field generated by the magnetic field generating device and holds the magnetic material;
A rotation mechanism that supports the holder so as to be rotatable in two or three dimensions;
and a rotation angle measuring means for measuring the rotation angle of the holder relative to the direction of the magnetic field. The easy magnetization direction inspection device according to claim 1, wherein the holder is made of a non-magnetic material. The easy magnetization direction inspection device according to claim 1 or 2, wherein the magnetic field generating device is a pair of ferrite magnets with opposite poles facing each other, and the holder is arranged on a straight line connecting the centers of the facing faces of the pair of ferrite magnets. A frame having a first plate-like member and a pair of second plate-like members arranged at both ends of the first plate-like member in a direction perpendicular to one plane of the first plate-like member is further provided,
The pair of ferrite magnets are fixed to the pair of second plate-like members, respectively,
The easy magnetization direction inspection device of claim 3, wherein the rotation mechanism comprises a rotating shaft having one end connected to the holder, and a bearing arranged on one plane of the first plate-shaped member and rotatably supporting the other end of the rotating shaft. The easy magnetization direction inspection device according to claim 4, wherein the frame is made of non-magnetic stainless steel. The easy magnetization direction inspection device according to claim 1 or 2, wherein the rotation angle measuring means comprises a pointer fixed to the holder and a display plate for measuring the rotation angle of the pointer.