JPH11233342A - Method for removing magnetic powder and removing device used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic powder removing device, etc., for quickly and surely removing magnetic powder which is stuck to the surface of a magnetized yoke, etc. SOLUTION: A yoke 10 of soft magnetic body comprising a plurality of arc-like counter parts 12 close to, almost parallel to a surface of a magnetized yoke, etc., to which magnetic powder sticks, a winding part 14 extending outside from each counter part 12, and an annular part 16 for connecting tips of the winding part 14, and a coil 18 wound around each winding part 14 are provided, and the yoke 10 and the coil 18 are engaged with a disk-like guide body 2 of insulating material which comprises, at its center, a round guide hole 8 of a diameter which is slightly smaller than a round hole 11 formed between the counter parts 12. When the coil 18 is energized, the magnetic field formed near each counter parts 12 attracts the magnetic powder sticking to the surface of near-by magnetized yoke, etc., for quick removal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic powder removing method for removing fine magnetic powder attached to the surface of a magnetized portion of a magnetized yoke for magnetizing a desired number of magnetic poles on a magnet material. And a magnetic powder removing device used for the same.

[0002]

2. Description of the Related Art In general, a ring-shaped rare earth bonded magnet used for a motor or the like is magnetized by a magnetizing device (hereinafter referred to as a magnetized yoke) 50 as shown in FIG. Become. The magnetized yoke 50 has a cylindrical main body 52.
And a columnar portion 54 erected from the center of the upper surface, and a magnetized portion 56 of a required number of poles formed on the peripheral surface. Except for the magnetized portion 56, the surfaces of the main body 52 and the columnar portion 54 are formed of an insulating material such as a synthetic resin. The magnetized part 56
5B is a part of a yoke 53 made of a soft magnetic material having a substantially U-shaped cross section in plan view, and a coil 57 is wound around each vertical piece 55 facing the center, as shown in FIG. Have been.

A pair of flowing water passages 58a penetrates vertically through the center of the yoke 53, makes a U-turn at the upper part of the columnar portion 54, and communicates with each other. -The magnetized yoke 50 is cooled from the inside by communicating with the drain pipes 58, respectively. Incidentally, reference numeral 5 in the figure
9, 59 are connection terminals from both ends of each coil 47.
Then, as shown in FIG. 5 (C), a plurality of ring-shaped bonded magnet materials 60 are fitted into the cylindrical portion 54 from above,
When the coil 57 of each magnetized portion 56 is energized, the magnet material 60 is magnetized from the inner peripheral surface side by the number of magnetic poles corresponding to the number of magnetized portions 56. Thereby, a permanent magnet 60 (a rare-earth bonded magnet) having eight magnetic poles can be obtained.
The magnetized permanent magnet 60 is removed from the columnar portion 54, and the surface of each magnetized portion 56 is cleaned with a cotton swab or the like before the next magnetizing step.

[0004] Such a cleaning operation is performed, for example, using Nd-Fe-B.
When magnetizing a rare-earth bonded magnet material, the magnet material is brittle, so fine magnet alloy powder (magnetic powder)
Is adhered to the surface of each magnetized portion 56, and is performed to remove this. If this cleaning is not performed, the magnetic powder will adhere to the surface of the magnet material 60 to be magnetized next when magnetized.
Also, if a rare earth bonded permanent magnet with fine magnetic powder attached to the surface is used for a motor, its performance will be reduced, or if it is used for a hard disk drive motor, it will adversely affect nearby magnetic recording media. There is.

[0005]

However, the work of wiping the magnetic powder attached to the surface of the magnetized portion 56 with the cotton swab or the like is as follows.
It is difficult to perform accurately, and it takes time and labor, so that there is a problem in terms of work efficiency. The present invention is a magnetic powder removing method for reliably and quickly removing magnetic powder required for the magnetized portion 56 of the magnetized yoke 50 as described above, and the cleaning method used therein can also be automated. It is an object of the present invention to provide a magnetic powder removing device.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has been made with the idea of bringing an electromagnet close to magnetic powder and adsorbing and removing the magnetic powder by its magnetic field. is there. That is, the magnetic powder removing method of the present invention is applied to the surface of a workpiece such as a magnetized yoke to which the magnetic powder adheres.
An opposing portion of the yoke is made to approach the surface substantially parallel to the surface, a current is supplied to a coil wound near the opposing portion, and magnetic lines of force pass along the axial direction of the coil and near the surface of the workpiece to which the magnetic powder adheres. By forming a magnetic field containing the magnetic powder, the magnetic powder is attracted to and removed from the opposing portion. According to this, by the electromagnet formed by the yoke and the coil, the lines of magnetic force passing through the opposing portion magnetize the magnetic powder attached to the surface of the magnetized yoke or the like and are attracted to the surface of the opposing portion approaching. Thereby, the magnetic powder can be accurately and quickly removed.

When the magnetic powder is magnetized in advance, the magnetic powder is repelled if it has the same polarity as that of the opposing portion and is not attracted. Therefore, for example, an alternating magnetic field may be formed by passing an alternating current through the coil. In addition, the magnetic powder removing device of the present invention includes a yoke made of a soft magnetic material including an opposing portion that is substantially parallel to and close to the surface of the workpiece such as a magnetized yoke to which the magnetic powder adheres. And a coil wound around the portion. According to this removing device, it is possible to surely perform the removing method by energizing the coil.

[0008] Further, a circular hole for inserting an object to be treated with magnetic powder adhered to the surface is provided at the center, a plurality of arc-shaped opposing portions provided along the circular hole, and an outer side from each opposing portion. A yoke of a soft magnetic material formed from a plurality of winding portions extending respectively, and an annular portion connecting the tips of the respective winding portions, and a plurality of coils wound for each winding portion of the yoke. And a magnetic powder removing device. According to this removing device, the magnetic powder adhered to the outer peripheral surface of the cylindrical magnetized yoke magnetized from the inner peripheral side of the ring-shaped magnet material or the outer peripheral surface of the ring-shaped or cylindrical magnet material is removed. ,
It is possible to reliably and easily remove it.

In addition, the yoke and the coils are fitted inside the removing device, and a circular guide hole having a diameter slightly smaller than the circular hole formed by each opposing portion of the yoke. A magnetic powder removing device having a guide body made of an insulating material is also included. As a result, it is possible to accurately arrange the surface of the cylindrical magnetized yoke close to the surface of the magnetized yoke without touching the opposing portion of the yoke, and to accurately pass magnetic lines of force to the magnetic powder to ensure its adsorption and removal. Can be. In addition, the guide body protects the yoke and is easy to process because it is made of an insulating material such as a synthetic resin. For example, the guide body can be connected to a piston rod of a fluid pressure cylinder. It becomes easy to perform the approach and the separation by automatic control.

Further, a plurality of arc-shaped cylinders are provided, which are entirely formed in a cylindrical hole into which the magnetic powder formed on the object to be treated is attached and which are provided along the circumferential direction on the outer peripheral surface of the cylindrical shape. A yoke of a soft magnetic material formed from a plurality of facing portions, a plurality of winding portions extending from the facing portions toward the central axis of the cylindrical shape, and a center portion connecting the tips of the winding portions. And a plurality of coils wound around each winding portion of the yoke.
According to this removing device, the magnetic powder adhering to the inner peripheral surface of the cylindrical magnetized yoke or the inner peripheral surface of the ring-shaped or cylindrical magnet material magnetized from the outer peripheral side of the ring-shaped magnet material is removed. It is possible to remove it reliably and quickly. The device of claim 3 and the device are concentrically arranged and used together,
It is also possible to substantially simultaneously remove the magnetic powder from both the inner and outer peripheral surfaces of the cylindrical magnetized yoke or the ring-shaped magnet material inserted between them.

[0011]

Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a perspective view of a magnetic powder removing device 1 of the present invention. The removing device 1 includes a guide body 2 made of an outer insulating material, a soft magnetic yoke 10 fitted inside the guide body 2,
And a coil 18 wound around zero. The guide body 2 has a disk shape with an outer diameter of 100 mm as a whole.
(B) As shown in FIG.
And a circular bottom wall 6, and a circular guide hole 8 having a diameter of about 28.5 mm is formed at the center of the bottom wall 6.
It is desirable to use a resin having excellent electrical insulation and chemical resistance, for example, a resin such as a thermosetting phenol resin (bakelite) as a material of the guide body 2.

The yoke 10 is made of a soft magnetic material such as pure iron, has a circular hole 11 having a diameter of about 28.7 mm at the center thereof, and is provided along the circumferential direction of the circular hole 11.
It comprises a plurality of arc-shaped opposing portions 12, eight winding portions 14 extending outward from each of the opposing portions 12, and a ring-shaped annular portion 16 connecting the respective ends of the winding portions 14. The facing portion 12 has a height of 10 mm, and the center of curvature is made to coincide with the center of the circular hole 11. Further, the outer diameter of the annular portion 16 is 90 mm, which is substantially the same as the inner diameter of the side wall 4 of the guide body 2. The winding portion 14 is a rectangular parallelepiped in which a square having a cross section of 6 mm in length and 6 mm in width is continuous, and is slightly smaller than each opposing portion 12 as shown in FIG.
A space of 2 mm is provided for winding. The yoke 10 is formed by precision casting, cutting, or the like.

Further, a coil 18 of a copper wire having a diameter of 0.5 mm is wound around the outside of each winding portion 14 of the yoke 10 in a single layer with a required number of turns in the same direction. Each coil 1
8 are connected in parallel to a power source (not shown). It is desirable that the outer periphery of the coil 18 be coated with a resin for insulation and protection. When the yoke 10 around which the coil 18 is wound is fitted into the guide body 2, the magnetic powder removing device 1 in which the circular guide hole 8 of the guide body 2 and the circular hole 11 of the yoke 10 are concentric is obtained. In addition, the guide body 2
The guide hole 8 is slightly smaller in diameter than the inner diameter (circular hole 11) between the opposed portions 12, and is close to the outer diameter of the workpiece to be inserted later.

FIG. 2A shows a magnetized yoke (device) 20 from which magnetic powder is removed according to the present invention. The magnetized yoke 20
Is a device similar to the magnetized yoke 40. A cylindrical portion 24 is provided upright at the center of the upper surface of the cylindrical main body 22. A number of magnetized portions 26 corresponding to the number of poles to be magnetized are provided on the circumferential surface of the cylindrical portion 24 in the circumferential direction. To obtain a permanent magnet by magnetizing, for example, Nd-Fe
A plurality of -B-based bond magnet materials 28 are fitted to the columnar portions 24 as shown by arrows in the figure, and current is applied to coils inside the respective magnetized portions 26 (not shown). Then, a magnetic field is applied to the inner peripheral surface of the magnet material 28 opposed to the magnet material 28 to provide a desired number of magnetic poles.

The magnetized bond magnet 28 is
Taken out of The fitting of the magnet material 28 and the removal of the permanent magnet 28 can be automatically performed by using, for example, a fluid pressure cylinder or a manipulator made of a non-magnetic material (not shown). By the way, fine magnetic powder having a particle size of about 0.1 to 10 μm adheres to the surface of each magnetized portion 26 after the magnet 28 is removed. Since the magnetic powder is a magnet alloy powder and is magnetized at the time of the magnetization, the magnetized portion 2 which does not form a magnetic field due to the stop of energization of the coil.
6 adheres to the surface. In order to remove the magnetic powder, the magnetic powder removing device 1 is used.

As shown in FIG. 2B, the removing device 1 is lowered so that the guide hole 8 and the circular hole 11 of the removing device 1 are inserted into the cylindrical portion 24 of the magnetized yoke 20. This operation is performed by a plurality of piston rods 19 of a hydraulic cylinder (not shown) whose lower end is connected to the side wall 4 of the guide body 2. Each magnetized portion 26 of the cylindrical portion 24 and each opposed portion 12 of the removing device 1 have the same number as each other, and they face each other to form eight pairs. As shown in FIG. 3, the guide hole 8 has only a very small gap between the cylindrical portion 24 and the opposing portions 12 and the magnetized portions 26 are evenly opposed to each other with a gap of about 0.1 mm. And make them parallel and close to each other.

In this state, an alternating current is applied to each coil 18 wound around the yoke 10 to form an electromagnet. Then, as shown in FIG. 3, a magnetic force line G that penetrates through the winding portion 14 of the yoke 10 and passes outside from the facing portion 12 and the annular portion 16 is formed along the axial direction of the coil 18. The lines of magnetic force G also apply a magnetic field to the adjacent magnetized part 26 when passing through the facing part 12. By receiving this magnetic field, the magnetic powder adhered to the surface of the magnetized portion 26 and magnetized in advance is attracted when the magnetic pole on the outer peripheral side and the magnetic pole of the facing portion 12 have different polarities. Then, it is attracted to the inner peripheral surface of the opposing portion 12 along the line of magnetic force G away from the magnetized portion 26.

In the state of the electromagnet, the removing device 1 is lifted by the rod 19 and taken out from the cylindrical portion 24. As a result, the surface of each magnetized portion 26 is reliably and quickly cleaned, and the next magnetized portion can be accurately performed. Further, the cycle time of the magnetizing step can be reduced, which can contribute to the improvement of production efficiency. In particular, by using the rod 19 or the like of the fluid pressure cylinder, if the step of removing the magnetic powder is performed by automatic control, the above-described effect can be remarkable. Further, it is possible to prevent the magnetic powder from being carelessly attached to the surface of the magnet to be magnetized, and it is possible to contribute to stabilization of the quality of the magnet. The magnetic powder sucked into the removing device 1 is separately removed.

In the above, the removing device 1 is connected to the magnetized yoke 2
The guide hole 8 of the guide body 2 is first passed through when the fitting is performed on the cylindrical portion 24 of the 0. However, the removal device 1 is turned upside down, and the guide of the guide hole 8 is also passed through the circular hole 11 of the yoke 10 first. The function is performed as described above. Further, the removing device 1 can remove not only the magnetized portion 26 of the magnetized yoke 20 but also the magnetic powder attached to the outer peripheral surface of the object to be processed having various cylindrical bodies. For example, by adjusting the diameter and the like of the circular hole 11 on the outer peripheral surface of the magnet material 28 before the magnetization, it can be utilized. Thereby, the magnetic powder adhering to the magnetized portion 26 of the magnetized yoke 20 can be removed or reduced in advance.

FIG. 4 relates to a magnetic powder removing apparatus 30 of a different form. The removing device 30 includes a yoke 31 made of the same soft magnetic material as described above and a plurality of coils 38. As shown in FIG. 4A, the yoke 31 has a cylindrical shape as a whole, and includes eight arc-shaped opposing portions 32 provided along the circumferential direction on the outer peripheral surface thereof. Eight winding portions 3 each extending toward the central axis of the cylinder
4 and a central portion 36 connecting the respective ends of the winding portion 34 to each other. A copper wire coil 38 is wound around each winding portion 34 in a required number of turns in one or more layers, and both ends thereof are connected in parallel to a power source (not shown). The central portion 36 of the yoke 31 has a round hole 3
9 are drilled.

FIG. 4B shows a state of use of the removing device 30. The workpiece from which the magnetic powder is removed is a magnetized yoke 4
0. The magnetized yoke 40 magnetizes the ring-shaped magnet material from the outer peripheral surface side, and has a large-diameter cylindrical hole 42 for accommodating the magnet material at the center thereof. And eight magnetized portions 44 having a substantially T-shaped cross section, and coils 46 wound around their inner portions 45, respectively. First, the cylindrical hole 42 of the magnetized yoke 40
Inside, a ring-shaped magnet material that moves in the front-rear direction as shown
(Not shown), and energize each coil 46. Then, the magnetic material is magnetized at a position facing each magnetized portion 44 according to the number thereof. Next, the magnetized permanent magnet is taken out from the circular hole 42. At the time of the magnetizing, each magnetized portion 4
The fine magnetic powder adheres to the inner peripheral surface of No. 4.

Next, as shown, the removing device 30 is inserted into the cylindrical hole 42 of the magnetized yoke 40 so as to be coaxial. This operation is performed, for example, by fixing one end of a piston rod such as a fluid pressure cylinder (not shown) to the round hole 39 in the yoke 31 of the removing device 30. When the opposing portions 32 of the yoke 31 of the removing device 30 and the magnetized portions 44 of the magnetized yoke 40 are parallel and close to each other, the insertion operation of the removing device 30 is stopped. And the removal device 3
An AC current is applied to each of the zero coils 38 to form a magnetic field having lines of magnetic force that extend in the respective coils 38 along the axial direction and outward from the outer peripheral surfaces of the respective opposing portions 32.

Then, the magnetic powder adhering to the inner peripheral surface of each magnetized portion 44 is attracted by the lines of magnetic force and adsorbed on the outer peripheral surface of the opposing portion 32 which comes close. Thereby, the magnetized yoke 4
Each of the 0 magnetized portions 44 is reliably and quickly cleaned, and the next magnetizing step can be performed accurately and appropriately. The removing device 30 can also be used to remove the magnetic powder adhering to the inner peripheral surface by inserting it into the inner peripheral side of a relatively large-diameter ring-shaped magnet material before magnetization. . Thereby, the magnetic powder adhering to the magnetized portion 44 of the magnetized yoke 40 can be removed or reduced in advance.
Further, the removing device 30 whose outer diameter is reduced to make the whole smaller is fitted in the circular hole 11 whose diameter is increased similarly to the removing device 1, and these two removing devices 1 and 30 are fitted.
Can be used concentrically, a ring-shaped magnet material is inserted between the two, and the inner and outer peripheral surfaces thereof can be simultaneously cleaned.

The present invention is not limited to the embodiments described above. For example, the magnetic powder removal device
A yoke including one opposing portion and one coil wound around the opposing portion of the yoke may be used.
Also, the current flowing through the coil is not limited to alternating current, and a direct current may be passed, and the direction of the direct current is appropriately switched in the opposite direction to change the direction of the magnetic lines of force in the generated magnetic field, thereby changing the direction of the magnetized portion. It is also possible to reliably suck and remove the magnetic powder attached to the surface. The removal of the magnetic powder adsorbed on the facing portion can be dealt with by flowing a current in the opposite direction.

Further, in the case of a magnetized yoke for magnetizing a plurality of poles on a linear bar-shaped magnet material, when cleaning the surfaces of a plurality of magnetized portions arranged in the linear holes, each magnetized yoke is required to be cleaned. It is also possible to use a magnetic powder removing device in which a plurality of yokes each having an opposing portion that can be approached substantially parallel to the magnetized portion and a coil wound around these are linearly arranged. The soft magnetic material is made of, in addition to the pure iron, silicon iron containing 1 to 3% of silicon, Cr
So-called electromagnetic stainless steel containing 13 to 18% of
B permalloy (45% Ni-Fe), PC permalloy (80% Ni-Mo-F
e) or PD permalloy (36% Ni-Fe) or the like may be used.

[0026]

According to the magnetic powder removing method and the removing apparatus of the present invention described above, for example, the magnetic powder adhering to the surface of the magnetized yoke can be reliably and promptly removed. Therefore, the cleaning operation for removing the magnetic powder can be accurately performed in a short time, and the process of magnetizing a magnet, for example, including the operation can be made more efficient. Claim 3
According to the magnetic powder removing devices of (4) and (4), the magnetic powder attached to the outer peripheral surface of the processing object having a cylindrical shape can be easily and quickly removed. Further, according to the magnetic powder removing device of the fifth aspect, the magnetic powder attached to the inner peripheral surface of the processing object having a cylindrical shape can be easily and quickly removed.

[Brief description of the drawings]

FIG. 1A is a perspective view showing one embodiment of a magnetic powder removing device of the present invention, and FIG. 1B is a sectional view taken along line BB in FIG.

2A is a partial schematic view of a magnetized yoke for removing magnetic powder, and FIG. 2B is a partial cross-sectional view showing a state in which the magnetic powder removing device of FIG. 1 is applied to the magnetized yoke.

FIG. 3 is an enlarged partial cross-sectional view of a part of FIG.

4A is a plan view showing a magnetic powder removing device of a different form, and FIG. 4B is a partial sectional view showing a state in which the device is applied to a magnetized yoke.

FIG. 5A is a perspective view of a general magnetized yoke, and FIG.
FIG. 3A is a cross-sectional view taken along line BB, and FIG. 3C is a schematic view illustrating a state of use of the magnetized yoke.

[Explanation of symbols]

 1, 30 magnetic powder removing device 2 guide body 8 circular guide hole 10, 31 yoke 11 circular hole 12, 32 facing portion 14, 34 winding Part 16: Annular part 18, 38: Coil 20, 40: Magnetized yoke 36: Central part G: Line of magnetic force

Claims (5)

[Claims] 1. An opposing portion of a yoke is made to approach a surface of an object to be processed such as a magnetized yoke to which magnetic powder adheres substantially parallel to the surface, and a coil wound near the opposing portion is energized. Forming a magnetic field including lines of magnetic force passing along the axial direction of the coil and near the surface of the workpiece to which the magnetic powder adheres, thereby attracting and removing the magnetic powder to the facing portion; Magnetic powder removal method. 2. A yoke made of a soft magnetic material including an opposing portion substantially parallel to and near a surface of an object to be processed, such as a magnetized yoke to which magnetic powder adheres, and wound around the opposing portion of the yoke. A magnetic powder removing device, comprising: a coil. 3. A circular hole for inserting an object to be treated on which magnetic powder adheres to the surface. A plurality of arc-shaped opposing portions provided along the circular hole, and an outer portion extending from each opposing portion. A yoke of a soft magnetic material formed from a plurality of winding portions extending respectively, and an annular portion connecting the tips of the respective winding portions,
A magnetic powder removing device, comprising: a plurality of coils wound around each winding portion of the yoke. 4. The removing device according to claim 3, further comprising:
The yoke and each coil are fitted inside, and a guide body made of an insulating material is added, which has a circular guide hole slightly smaller in diameter than the circular hole formed by each opposing portion of the yoke. A magnetic powder removing device, characterized in that: 5. A plurality of arc-shaped cylinders, each of which has a cylindrical shape which can be inserted into a cylindrical hole to which magnetic powder formed on an object to be processed adheres, and which is provided along a circumferential direction on an outer peripheral surface of the cylindrical shape. A yoke of a soft magnetic material formed from a plurality of facing portions, a plurality of winding portions extending from the facing portions toward the central axis of the cylindrical shape, and a center portion connecting the tips of the winding portions. And a plurality of coils wound around each of the winding portions of the yoke.