JP2002033214A - Magnetizing device and method for taking out permanent magnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for easily taking out a permanent magnet which is not easily taken out from between pole pieces in a conventional magnetizing device, as the dimension of the magnet is large and a wide magnetic field is needed for the magnetization of the magnet, and to provide a device for taking out the permanent magnet. SOLUTION: A magnetizing device is constituted in a structure that a magnetic field gradient can be formed between a pair of pole pieces by providing each inclination on the magnetic pole surfaces opposing to each other of the pole pieces. In this structure, a reverse magnetic field having a gradient is applied to a permanent magnet subsequent to the magnetization of the magnet, and the take-out of the magnet is facilitated utilizing the repulsive force of the magnet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the magnetization of a permanent magnet, and more particularly, to a method and an apparatus for safely and easily removing a permanent magnet from a magnetizer after completion of the magnetization. Things.

[0002]

2. Description of the Related Art As a device for magnetizing a permanent magnet, electricity stored in a capacitor is instantaneously passed through an air-core coil.
A device using an air-core coil that uses an induction magnetic field generated in the coil, and an electromagnet that uses a magnetic field generated between the pair of pole pieces by passing a steady current to the coil arranged outside the pair of pole pieces that constitute the magnetic circuit There is a device.

In the case of magnetizing a permanent magnet having a large magnetic pole surface and requiring a large magnetic field for magnetization, a device using an air-core coil has a large diameter of the air-core coil, and a sufficient magnetic field cannot be obtained. Electromagnetic devices are frequently used. FIG. 4 schematically shows an example of a device using an electromagnet. The main components are a pair of pole pieces 41, a coil 42 for generating a magnetic field, a frame 43 for supporting the pole pieces 41 and the coil 42, and a handle 44 for adjusting the interval between the pole pieces.

As a representative of a permanent magnet requiring a large magnetic field for magnetization, rare earth magnets such as Sm-Co type and Nd-Fe-B type are mentioned. In this case, 1.5 to 5 Tesla (hereinafter, T and T) are used. ) Magnetic field is required. Since a large attractive force acts between the magnetized permanent magnet and the pole piece, a correspondingly large force is required to take out the permanent magnet from between the pole pieces. Due to the difficulty of removal after magnetization, in the case of a permanent magnet having a large size, that is, a large magnetic pole surface, it is not possible to perform magnetization or a large-scale removal device needs to be prepared in advance.

[0005] The reason why a large force is required to take out the permanent magnet from between the pole pieces after the magnetizing operation is as follows.
The following points are mentioned. In an electromagnet, if the magnitude of the current flowing through the coil is the same, the magnitude of the magnetic field generated between the pole pieces decreases as the distance between the pole pieces increases. On the other hand, when the distance between the pole pieces is constant, the magnetic field between the pole pieces can be increased by increasing the current flowing through the coil.

However, when a large current is applied to the coil, the size and weight of the electromagnet itself increase, and the price of the electromagnet also increases. Therefore, when magnetizing, it is necessary to make the distance between the pole pieces as small as possible. If a magnetized permanent magnet is arranged with a very small air gap between the pole pieces of the electromagnet, the permanent magnet and the pole piece form a magnetic circuit, and are in a state close to a closed magnetic circuit.

[0007] For this reason, the attractive force between the permanent magnet and the pole piece becomes extremely large, and a very large force is required to remove the permanent magnet from the pole piece. In order to avoid this, there is a method to increase the interval between the pole pieces when removing the permanent magnet. Become.

[0008] As another method of extracting the permanent magnet, a magnetic field is applied to the magnetized permanent magnet in a direction opposite to that in the case of magnetizing, and the permanent magnet is removed from the pole piece using a repulsive magnetic field. There is a method of discharging. However, in this case, it is necessary to apply a considerably large magnetic field, which is not only dangerous, but also may cause permanent magnets to be demagnetized due to the reverse magnetic field. .

[0009]

SUMMARY OF THE INVENTION Accordingly, the technical problem of the present invention is to provide a permanent magnet having a high magnetic property in which a large attractive force acts between the pole piece and the pole piece from the pole piece safely and securely. An object of the present invention is to provide a method for removing the magnet and improve productivity of the permanent magnet.

[0010]

In a magnetizing device using a conventional electromagnet, opposed magnetic pole surfaces of a pair of pole pieces are:
The pole faces are parallel and have a symmetric shape having a center point such as a circle or a square. For this reason, the magnetic field gradient between the pole pieces is also symmetric about the center point, and the magnetized permanent magnet is drawn to the center, which is the most stable position between the pole pieces, and stands still.

Therefore, even if a reverse magnetic field is applied to the magnetized permanent magnet, the force acting on the permanent magnet becomes uniform in all directions, making it difficult to remove the permanent magnet from between the pole pieces. The present invention has been made by reviewing the structure of a magnetizing device using a conventional electromagnet.

That is, according to the present invention, in a permanent magnet magnetizing apparatus including an electromagnet and a pair of pole pieces, an interval between opposing surfaces of the pair of pole pieces has an inclination. It is a magnetizing device.

Further, the present invention uses the above-mentioned magnetizing device,
After magnetizing the permanent magnet between the pair of pole pieces, by applying a magnetic field in a direction opposite to the magnetization of the permanent magnet, removing the permanent magnet from between the pair of pole pieces. A method for extracting a permanent magnet.

Further, according to the present invention, in the above-mentioned method for removing a permanent magnet, the magnetization and the removal are performed by loading the permanent magnet into a container made of a non-magnetic material. Is the way.

[0015]

[Action]

In the permanent magnet magnetizing device according to the present invention, the magnetic field between the pole pieces is small at a place where the gap is large by giving an inclination to the gap between the opposing surfaces of the pole pieces.
A magnetic field gradient is formed such that the magnetic field gradient becomes large at a portion where the interval is small.

For this reason, when a reverse magnetic field is applied to the magnetized permanent magnet between the pole pieces,
A reverse magnetic field having a different magnitude is applied to each part, and a force is applied in a direction perpendicular to the magnetic field, that is, in a direction parallel to the pole face of the pole piece, and acts to take out the permanent magnet from the pole piece. As a result, the permanent magnet comes out from between the pole pieces by applying a small reverse magnetic field with the electromagnet.

In addition, since the direction in which the permanent magnet comes out is determined by the direction of the inclination of the opposing surface of the pole piece, the convenience of post-processing such as automatically transferring the permanent magnet to the next process after removing the permanent magnet is also improved. I do. In addition, the combined use of the method of charging the permanent magnet to be magnetized into a container made of a non-magnetic material such as stainless steel makes it easier to magnetize and take out the magnetized magnet.

[0019]

Next, an embodiment of the present invention will be described with reference to the drawings. 80m diameter as permanent magnet
m, a SmCo-based rare earth sintered magnet having a height of 40 mm was prepared. The axis of easy magnetization of this permanent magnet is in the height direction.

FIG. 1 schematically shows a pole piece of a magnetizing device according to the present invention. This pole piece has a cylindrical shape with a diameter of 150 mm, and the magnetic pole surface of the upper pole piece 12 is provided with an inclination of 5 ° with respect to a plane perpendicular to the center axis of the pole piece as shown in the figure. . On the other hand, the pole face of the lower pole piece 13 is a plane perpendicular to the central axis. The inclination may be provided on the lower pole piece or on both the upper and lower pole pieces. However, in consideration of mounting a permanent magnet, a structure as shown in FIG. 1 is desirable.

FIG. 3 schematically shows a conventional magnetizing device. In this device, the magnetic pole faces of the upper and lower pole pieces 31 are not inclined, and are perpendicular to the center axis of the pole pieces. Here, in order to evaluate the easiness of taking out the permanent magnets of the present invention and the conventional example, for each magnetizing device, a reverse magnetic field is applied to the permanent magnets after magnetizing and the force required to take out the magnets. I asked.

Here, in both the present invention and the conventional example, the interval between the pole pieces was set to be 47 mm at the narrowest point. In addition, a spring balance was used to measure the force required to take out the permanent magnet. The results are shown in Table 1.

[0023]

[Table 1]

According to these results, in the device according to the present invention, the magnitude of the reverse magnetic field was 0.05 T, and the force required to remove the permanent magnet was 9.8 Newton (hereinafter, referred to as N). On the other hand, in the conventional device, in order to take out the permanent magnet with the same force of 9.8 N, a reverse magnetic field of 0.4 T was required. Further, in the column of the result of the present invention in Table 1, in the region where the magnitude of the reversal magnetic field is 0.2 T or more, the force required for extraction is not described.
The permanent magnet comes off in the right direction in FIG.

Next, the force required to insert the permanent magnet into the container made of non-magnetic material and to remove it was determined. FIG. 2 is a schematic diagram showing the method. In this case, a container for magnetization was prepared using a non-magnetic stainless steel plate having a thickness of 3 mm. The inner dimensions are 81 mm x 400 mm x 41 mm.
The result of measuring the output of the permanent magnet using this container,
It was similar to that shown in Table 1. The material used for the magnetizing container is not limited as long as it is a non-magnetic structural material other than the above.

[0026]

As described above, according to the present invention, the permanent magnet which is difficult to remove from between the pole pieces in the conventional apparatus because of its large size and requiring a large magnetic field for magnetization. Can be easily taken out. In addition, it has become possible to magnetize a permanent magnet that could not be magnetized because it was difficult to take out with a conventional device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state of a permanent magnet magnetizing operation by the device of the present invention.

FIG. 2 is a diagram showing a state of a magnetizing operation of a permanent magnet using a container for magnetizing a non-magnetic material.

FIG. 3 is a diagram showing a state of permanent magnetizing work by a conventional device.

FIG. 4 is a diagram showing a conventional example of a magnetizing device using an electromagnet.

[Description of Signs] 11 Permanent magnet 12, 13, 31, 41 Pole piece 21 Magnetization container 22 Protruding rod 43 Frame 44 Pole piece interval adjustment handle

Claims (3)

[Claims] 1. A permanent magnet magnetizing device comprising an electromagnet and a pair of pole pieces as components, wherein a distance between opposing surfaces of the pair of pole pieces has an inclination. Porcelain device. 2. After magnetizing a permanent magnet between the pair of pole pieces using the magnetizing device according to claim 1,
A method for removing a permanent magnet, wherein the permanent magnet is removed from between the pair of pole pieces by applying a magnetic field in a direction opposite to the magnetization of the permanent magnet. 3. The method for removing a permanent magnet according to claim 2, wherein the magnetization and the removal are performed by loading the permanent magnet into a container made of a non-magnetic material. Removal method.