JP3027673B2 - Surface treatment method using moving magnetic field - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment method using a moving magnetic field, and more particularly to a technique for polishing a surface of a non-magnetic material with high efficiency.

[0002]

2. Description of the Related Art As a conventional magnetic polishing method, for example, a set of permanent magnets having different magnetic poles facing each other is disposed on both sides of a non-magnetic tube, and magnetic abrasive grains are supplied onto the inner surface of the non-magnetic tube or the inside of the tube is supplied. There is a method in which a permanent magnet or a non-magnetic tube is rotated while a magnetic material polishing tool is arranged, thereby polishing the inner surface of the non-magnetic tube. In this method, four or more permanent magnets having different magnetic poles inward may be alternately arranged around the tube. On the other hand, a plurality of electromagnetic coils are arranged around the non-magnetic tube, and alternating-current power of different phases is supplied to the electromagnetic coil to form a rotating magnetic field inside the non-magnetic tube. There is also a method of rotating and driving a magnetic polishing tool.

[0003]

The above-mentioned magnetic polishing method is very preferable because the inner surface of the non-magnetic tube, which is difficult to mechanically polish, can be polished in a non-contact manner. Must be applied. Further, in order to ensure the uniformity of the polishing amount and the surface roughness, it is necessary to adjust the moving cycle and the moving speed of the non-magnetic tube in the axial direction by repeating a number of trials. In view of the above situation, it is an object of the present invention to provide a surface treatment method capable of increasing the amount of processing compared to the conventional method by a method other than increasing the magnetic force and increasing the uniformity of the polishing amount and the surface roughness. And

[0004]

Means taken by the present invention to achieve the above object is to dispose a plurality of magnetic poles so as to face each other inward around a non-magnetic material, A surface treatment method using a moving magnetic field for treating a surface of a non-magnetic material by moving the magnetic pole relative to a non-magnetic material in a state where a magnetic material is provided on the surface, wherein a plurality of the magnetic poles are interconnected. The magnetic poles are arranged around the non-magnetic body at an interval, and the plurality of magnetic poles are all the same. Preferably, the non-magnetic member is a non-magnetic tube, and the plurality of magnetic poles are moved in the axial direction of the non-magnetic tube while rotating relative to the non-magnetic tube about the axis thereof. Further, it is preferable that the magnetic pole is a magnetic pole of a permanent magnet mounted on an inner peripheral surface of the through-hole with respect to a rotating member having a through-hole through which a nonmagnetic material is inserted.

[0005]

A feature of the present invention resides in a magnetic field formed by a magnetic pole arrangement in which the same magnetic poles are opposed or adjacent to each other (hereinafter referred to as a repulsive magnetic field), and a magnetic field formed by a conventional arrangement in which different magnetic poles are opposed or adjacent to each other. (Hereinafter, it is called an attraction magnetic field.)
Is considered to have the following differences. Generally, the force acting on a magnetic material is represented by the product of the magnetic field strength and the rate of change of the magnetic field. The magnetic field strength at the processing site is generally considered to be larger in the case of the attracted magnetic field, but the rate of change of the magnetic field is much larger in the case of the repelling magnetic field. As a result, the processing pressure represented by the product of the two is larger in the repulsive magnetic field. In addition, the change in the magnetic flux distribution causes the magnetic material to be concentrated near the surface of the non-magnetic material and also increases the contact area of the magnetic material. Further, when a magnetic field is moved relative to the surface of a non-magnetic material, a magnetic force and a contact resistance act on the magnetic material. At the time of processing, a phenomenon occurs in which the magnetic material is dragged and moved to the surface of the non-magnetic material due to contact resistance, and the processing is stopped when the magnetic material moves together with the surface of the non-magnetic material. What resists this contact resistance is the tangential component of the surface of the non-magnetic material due to the magnetic force, and it is considered that the repulsive magnetic field is also larger for this tangential component for the same reason as the processing pressure.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a surface treatment method using a moving magnetic field according to the present invention will be described with reference to the drawings. As shown in FIG. 1, a non-magnetic tube 1 is inserted into a through-hole 2a having a circular cross section formed in a rotating member 2, and support blocks 3A and 3B of magnetic material are placed at opposing positions on the inner peripheral surface of the through-hole 2a. Is fixed.
On the end faces of the support blocks 3A, 3B, permanent magnets 4A,
4B, and the magnetic pole faces thereof are opposed to each other. In the conventional polishing method, the permanent magnets 4A and 4B are mounted with their opposite poles (eg, N pole and S pole) facing each other, but in the present embodiment, the permanent magnets 4A and 4B are in a state where the same poles face each other. Mounted.

The rotating member 2 is rotatably supported by a support frame (not shown), and is rotated by a drive motor also mounted on the support frame. The support frame itself extends in the direction in which the non-magnetic tube 1 extends (the non-magnetic tube 1
Is preferably supported in the vertical direction to supply the slurry described below. ) Is moved by a guide provided along the line.

FIG. 2 shows that the magnetic polishing with the above-described structure is performed by using a diameter of 25 mm.
The surface roughness and the processing amount when applied to an aluminum pipe with a thickness of 1 mm and a thickness of 1 mm are shown for the conventional example (attraction magnetic field) in which different poles are opposed and the present embodiment (repulsive magnetic field) in which the same poles are opposed. It is. The gap (gap amount) between the magnet and the outer surface of the pipe is 1.8 mm, the same rare earth magnet is used in both cases, and the transmitted magnetic force measured at the center of the pipe is 4500 in the conventional example.
G, 3500 G in this example.

The magnetic abrasive used was # 1200 powder, and 200 g of this powder dispersed in 2000 cc of oil was fed into a pipe at a rate of 5 cc / min as a slurry. The rotation speed of the rotating member 2 is 150
0 rpm, the support frame has a period of 1 in the axial direction of the non-magnetic tube.
While being reciprocated at an Hz stroke of 28 mm, one was moved at a moving speed of 50 mm / min.

As shown in FIG. 2, the amount of processing increases in both the present embodiment and the conventional example in proportion to the processing time.
In this embodiment, an extremely large processing amount of about four times that of the conventional example is obtained. On the other hand, no significant difference is observed between the two. This is because the surface roughness before processing should have been quickly removed because the processing amount of this example was large, but because the coarse-grained abrasive was used and the workpiece was a soft aluminum pipe. It is believed that there is.

Next, using the apparatus shown in FIG. 3A, the processing pressure was measured according to the conventional example and the present embodiment. Two stainless steel plates (SUS304) 10a, 10b
1 fixed part 11a and fixed part 12a of lower plate 12,
They are arranged parallel to each other. A strain gauge 13 is formed on the surface of the stainless steel plate 10a. Lower surface of upper plate 11 and lower plate 12
Permanent magnets 14A and 14B are attached to the upper surface of
Stainless steel plate (S) sandwiched between permanent magnets 14A and 14B
(US304) Iron powder 15 was supplied between 10a and 10b.

In the above structure, the stainless steel plate 10
a, gap (gap amount) gp between the outer surface of 10b and the pole face
The output of the strain gauge 13 was measured when the opposite magnetic poles of the permanent magnets 14A and 14B were changed to different polarities (conventional example) and when the permanent magnets 14A and 14B were set to the same polarity (this embodiment). Here, when the permanent magnets 14A and 14B are arranged in the attraction position, FIG.
As shown in FIG. 3, iron powder is distributed vertically between the stainless steel plates 10a and 10b. However, when the permanent magnets 14A and 14B are arranged in a repulsive arrangement, as shown in FIG. Each is separated on the inner surfaces of the steel plates 10a and 10b and distributed in a spread state. As shown in FIG. 3D, the planar distribution of the iron powder in the case of the repulsion arrangement is distributed around the position immediately above the magnetic pole.

According to the above measurement, as shown in FIG. 4, the pressure on the processing surface due to the repulsive magnetic field is larger than the processing pressure of the attractive magnetic field as a whole. The difference is getting bigger. Therefore, according to the repulsive magnetic field, even if the gap amount is increased, the reduction amount of the processing pressure is small, and the influence of the magnetic pole arrangement on the polishing is weak. In addition, the distribution of the magnetic abrasive grains in the attraction magnetic field spreads throughout the inside of the pipe according to the distribution of the magnetic flux, but in the repulsive magnetic field, the magnetic abrasive grains do not stay inside the pipe but gather on the inner surface of the pipe (that is, the processing portion) and polish. Many of the materials work effectively. This can be understood from the distribution of the iron powder in FIG. In other words, since the repulsive magnetic field has a larger contact amount and contact area of the abrasive with the processing surface, it can be polished more efficiently. The increase in the processing amount in FIG. It is also due to the increase.

FIG. 5 shows a magnetic flux distribution according to the magnetic pole arrangement of this embodiment. In the repulsive magnetic field, since the magnetic lines of force of the permanent magnet are distributed so as to exclude each other, the magnetic force at the center of the pipe is weakened, but the magnetic flux passing through the inner surface of the pipe increases. This indicates that in the repulsive magnetic field, the magnetic field strength increases rapidly when approaching one of the magnetic poles, and the rate of change of the magnetic field on the polished surface is large,
The processing pressure on the polished surface of the magnetic field and the resistance to movement in the tangential direction (hereinafter, these two are referred to as processing forces) are increased. In addition, the repulsive magnetic field increases the amount of action of the polishing abrasive grains in order to concentrate the distribution of the magnetic abrasive grains in the pipe on the polishing surface, and the distribution of the magnetic abrasive grains also spreads on the polishing surface according to the magnetic flux distribution. The working area also increases.

Therefore, the amount of machining can be greatly increased as a whole, and the polishing area is large and the polishing is performed. For example, the polishing is performed in both the portion where the magnetic flux enters the inside of the pipe and the portion where the magnetic flux exits the outside of the pipe again. Since the change in the processing force on the surface is gentle, a uniform polished surface can be easily obtained even if the reciprocating operation is not sufficiently performed, for example, in the pipe axis direction. That is, it is possible to increase both the polishing rate and the polishing uniformity.

FIG. 6 shows a case in which four permanent magnets having S poles and N poles are alternately directed inward around the pipe (a), and a case in which all four N poles are directed inward (b). 3 shows the distribution of the lines of magnetic force. In the arrangement shown in FIG. 6A, similarly to the above, the rate of change of the magnetic field is small, and the polished portion is only eight places on the circumference, and the magnetic flux is also concentrated in the direction of the opposite pole of the adjacent magnet. In both the circular section of the pipe and the section including the axis, the polished portion is narrow and the boundary portion with the non-polished portion is steep. In contrast, FIG.
In the arrangement shown in (b), the processing pressure increases due to the large rate of change of the magnetic field on the inner surface of the pipe, and the polishing area is large because polishing is performed at 16 locations. A polishing region is formed.

The inner surface of a stainless steel (SUS304) flexible tube (bellows tube or bellows) shown in FIG. 7 was polished in the same manner as in the above embodiment. With the same device as in FIG. 1, the rotation speed of the rotating member is 2700 rpm,
Reciprocating frequency 2Hz, reciprocating stroke 28mm,
Slurry drip 5cc / min, slurry composition (2-4μ
Polishing is performed by dispersing 0.05 g of magnetic abrasive grains of m diameter in 10 cc of oil, adding 0.8 g of iron powder of 330 μm diameter as a polishing reinforcing agent), moving speed of the rotating member 50 mm / min, and processing time 30 min. went.

As a result of the above, the conventional method performed under the same conditions is insufficiently processed as a whole, and only the peak P of the corrugated cross section of the bellows has a mirror surface. The inclined portion S was hardly polished. On the other hand, in this example, the processing amount was sufficient, and mirror polishing could be performed as a whole. The sloping portion S and the valley portion V of the corrugated cross section were sufficiently polished similarly to the peak portion P.

In the attracting magnetic field, the whole inside of the bellows is filled with magnetic abrasive grains, and the peak P tends to be polished.
Until the magnetic abrasive grains are hard to enter. Even if the amount of the magnetic abrasive grains is increased, the magnetic field distribution becomes close to a uniform distribution, the required magnetic field distribution (change rate of the magnetic field) cannot be obtained, and the processing force is small. On the other hand, in the repulsive magnetic field, the rate of change of the magnetic field is extremely large at the valley V because the magnetic field is sharply increased in the direction of approaching the magnetic pole. Therefore, if an appropriate amount of magnetic abrasive is supplied, the magnetic field is limited to the peak P. However, the sloping portion S and the valley portion V are sufficiently polished.

As described above, the present embodiment is a simple method, but has an extremely large effect. The present invention is a novel surface treatment method that satisfies both the processing amount and the uniformity. In this embodiment, the method for polishing the inner surface of the non-magnetic tube has been described. However, it is apparent that the present invention can be applied to the surface polishing of other non-magnetic materials such as a flat plate and a spherical portion. For example, when polishing the surface of a flat plate, the slurry may be supplied onto the surface by bringing the flat plate close to one of the opposing magnetic poles. The moving magnetic field does not need to be formed by rotational movement as in the above embodiment, but may be formed by another operation such as a simple reciprocating operation.

As the magnetic material for polishing, other than the above-mentioned magnetic abrasive grains, a polishing tool made of a magnetic material with a polishing cloth adhered to the surface may be arranged and driven by a magnetic force. The present invention can be widely applied to other surface treatments such as grinding and surface etching besides polishing, and in these other treatments, the increase in the processing power and the processing area effectively acts. Various permanent magnets can be used as the magnet, and an electromagnet may be used instead of the permanent magnet. The number of magnets may be two or more. When a large number of magnets are used, it is necessary to appropriately set the arrangement interval and the gap amount with the surface to be polished.

[0022]

As described above, according to the present invention, a plurality of magnetic poles are disposed so as to face each other around a non-magnetic material, and a magnetic material is provided on the inner surface of the non-magnetic material. A surface treatment method using a moving magnetic field that treats a surface of a non-magnetic material by moving the magnetic poles relative to the non-magnetic material, wherein a plurality of the magnetic poles are spaced apart from each other by Since the plurality of magnetic poles are arranged around the same magnetic pole, the processing amount can be increased only by changing the magnetic pole arrangement, and a highly uniform surface treatment can be easily performed. .

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a main part of a polishing apparatus for illustrating a method for polishing the inner surface of a non-magnetic tube according to an embodiment of the present invention.

FIG. 2 is a graph showing the surface roughness of the inner surface of the non-magnetic tube after polishing and the amount of polishing processing according to the example in comparison with a conventional example.

3A is a conceptual diagram showing a structure of an experimental device for measuring a polishing pressure, FIG. 3B is a cross-sectional view showing a distribution of iron powder by a conventional attractive magnetic field, and FIG. FIG. 3D is a cross-sectional view illustrating the distribution of iron powder due to a repulsive magnetic field, and FIG.

FIG. 4 is a graph showing a relationship between a gap amount between a magnetic pole and a stainless steel plate and an output voltage of a strain gauge in comparison with a conventional example.

FIGS. 5A and 5B are explanatory diagrams showing a magnetic flux distribution in the present embodiment.

FIG. 6A is an explanatory diagram showing a magnetic flux distribution of a conventional system composed of four magnets in which different poles are alternately inwardly directed, and FIG. 6B is a diagram illustrating a magnetic flux distribution when all four same magnetic poles are inwardly directed; FIG.

FIG. 7 is a sectional view of a flexible tube used as a workpiece for inner surface polishing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Non-magnetic tube 2 Rotating member 2a Through hole 3A, 3B Support block 4A, 4B Permanent magnet

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-41172 (JP, A) JP-A-61-244456 (JP, A) JP-A-62-113952 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) B24B 31/112 B24B 37/00

Claims (3)

(57) [Claims] A plurality of magnetic poles are formed around a non-magnetic material.
Arranged so that they face each other inside, and on the inner surface of the non-magnetic material
With the magnetic material applied to the magnetic pole,
Treat the surface of non-magnetic material by moving it relatively
A surface treatment method using a moving magnetic field,
The poles are arranged around the non-magnetic material at a distance from each other
In addition, a surface treatment method using a moving magnetic field , wherein all of the plurality of magnetic poles are the same magnetic pole . 2. The non-magnetic material according to claim 1, wherein the non-magnetic material is a non-magnetic material.
A plurality of said magnetic poles, the axis of which is
Relative to the axis of the non-magnetic tube
A surface treatment method using a moving magnetic field, wherein the surface is moved in a direction . 3. The magnetic recording medium according to claim 1, wherein
The pole corresponds to a rotating member having a through hole through which a non-magnetic material is inserted.
The magnet of the permanent magnet attached on the inner peripheral surface of the through hole
A surface treatment method using a moving magnetic field, which is a pole .