JPH0494515A - Manufacture of u-shaped core - Google Patents

Abstract

PURPOSE:To simplify a manufacture process by molding a magnetic material into an L shape having a side column and a common column connected with one end of the side column. CONSTITUTION:An L-shaped hole 51a is formed in the central part of a mold frame 51. Then, a bottom force 53 is inserted and fitted from under the hole 51a where magnetic material-made granulated powder 54 is put in the hole 51a. Then, a top force 52 is inserted and fitted from above the hole 51a. The granulated powder 56 filled in the hole 51a of a single action press thus set up is pressurized and molded. In succession with this, a common column 62 is cut and machined by a grinding device, thereby forming a cut groove 86 and a U-shaped core.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a U-air core made of a magnetic material used for a magnetic core of a choke coil, a noise filter, etc. The present invention relates to a method for manufacturing a U-shaped core by performing molding and cutting.

(Prior Art) In recent years, there has been an increasing demand for smaller electronic devices, and in particular, there is a demand for thin and lightweight electronic devices that can be carried and used outdoors or indoors.

Therefore, it is desired that the chiyoku twill and noise filters used in these electronic devices be made smaller and lighter.

Therefore, cores made of magnetic materials used as the magnetic cores of choke coils, noise filters, etc. are strongly required to be thinner and lighter, and various proposals have been made to date.

A U-shaped core is known as a magnetic core incorporated in the choke coil or the like, and a conventional example of the U-shaped core will be described with reference to FIGS. 7 and 8.

In FIG. 7, a U-shaped core l made of a magnetic material such as ferrite has a central magnetic leg 2 which is elongated upward, and side magnetic legs 3 having the same shape as the central magnetic leg 2. The yoke portions 5 are disposed through the yoke portion 5, and each end is connected by a yoke portion 5.

At this time, the surfaces opposite to the connecting surfaces where the central magnetic leg 2 and the side magnetic legs 3 are connected to the yoke part 5 are formed on the same plane, and the central magnetic leg 2, the side magnetic legs 3 and the yoke part The upper and lower rectangular surfaces constituted by 5 are also formed on the same plane.

A coil bobbin 6 made of a coil or the like wound with enameled wire or the like is fitted into the central magnetic leg 2 of the U-shaped core I, as shown by the imaginary line in the figure. By combining the U-shaped core 1 with another diamond-shaped core, the choke coil or the like can be constructed.

When the coil bobbin 6 is fitted into the U-shaped core 1 as described above, the upper and lower windings of the coil bobbin 6 are
It protrudes by two widths from the upper and lower surfaces of the central magnetic leg 2 of the U-shaped core I, so it cannot be said that the dimensions of each part are effectively utilized in the structural design of the U-shaped core I, and furthermore, the transformer etc. There were problems such as poor stability when mounting it on a circuit board, etc.

For this reason, a U-shaped core has been devised with a structural design that makes effective use of the dimensions of each part, and this U-shaped core will be explained with reference to FIG. 8.

In the U-shaped core 1, a central magnetic leg 12 elongated in the horizontal direction extends from approximately the center of the right front side of the yoke portion 15, and a side magnetic leg is connected from the central magnetic leg 12 through a groove 14. 13 are arranged, and one end of the side magnetic leg 13 is connected to the yoke portion 15.

At this time, the center magnetic leg 12 and the side magnetic legs 13 are connected to the yoke portion 1.
5 are formed on the same plane, and the upper and lower rhombic surfaces formed by the side magnetic legs 13 and the yoke portion 15 are also formed on the same plane.

Furthermore, since the central magnetic leg 12 is connected to the substantially central portion of the right front surface of the yoke portion 15, there are spaces 17a, 17 from the upper and lower surfaces of the central magnetic leg 12 to the upper and lower surfaces of the yoke portion 15.
b is provided.

A coil bobbin 16 is fitted into the central magnetic leg I2 of the U-shaped core 11, as shown by the imaginary line in the figure, and further, by combining the U-shaped core 11 with another U-shaped core, , choke coils, etc. are formed.

According to the U-shaped core 11, the central magnetic leg 12 is elongated in the lateral direction, and there are spaces 17a above and below the central magnetic leg 12 compared to the heights of the side magnetic legs 13 and the yoke portion 15. , 17
b, and since the coil bobbin 16 fitted to the central magnetic leg 12 does not substantially protrude beyond the upper and lower surfaces of the side magnetic legs 13 and the yoke portion 15, the U-shaped core 11 can be made smaller. This means that the structure has been designed to accommodate changes such as

Next, a manufacturing method for manufacturing the U-shaped core I using a dry single-acting press device 25 will be described in FIGS. 9(a) and (
This will be explained with reference to b).

FIG. 9(a) is a plan view showing a state in which the lower mold 23 is fitted into the formwork 21 of the single-acting press device 25, and FIG.
), the granulated powder 24 made of a magnetic material filled in the U-shaped molding hole 2]a of the same mold frame 21 is inserted into the upper mold 22 and the lower mold 23.
FIG. 3 is a cross-sectional view taken along line AA, showing a state in which pressure is applied.

The lower mold 23 is inserted from below into the U-shaped molding hole 21a formed in the mold frame 21, and the granulated powder 24 made of a magnetic material is filled into the U-shaped molding hole 21a, and the upper mold 2 is inserted from above.
2 is inserted and pressurized to mold the U-shaped core 1.

At this time, the pressure surface of the upper mold 22 and the pressure surface of the lower mold 23 are
In order to uniformly pressurize the granulated powder 24, the tops of the center magnetic legs 2, side magnetic legs 3, and yoke portions 5 of the U-shaped core 1, which are each formed on a substantially horizontal plane, are molded. The lower surfaces are formed on the same plane.

According to the above-mentioned single-acting type brace device 25, the U-shaped core 1 has a uniform density in each part, and the molding process is performed by a simple operation, so that the single-acting type press device 25 has a small size and a simple configuration. It had the characteristics of fast molding speed and suitable for mass production.

Next, the double-acting brace device 35 causes the U-shaped core 11 to
A manufacturing method for manufacturing the same will be explained with reference to FIGS. 10(a) and (b).

FIG. 10(a) is a plan view showing a state in which the lower mold 33 is fitted into the mold 31 of the double-acting brace device 35, and FIG. 10(b) is a rectangular molding hole 31a of the mold 31. FIG. 3 is a sectional view taken along line B-B showing a state in which granulated powder 34 made of a magnetic material filled therein is pressed by an upper mold 32 and a lower mold 33.

A lower mold 33 is fitted from below into a rectangular molding hole 31a formed in the formwork 31, and granulated powder 34 made of a magnetic material is filled into the rectangular molding hole 31a, and an upper mold 32 is fitted from above. Pressure is applied by inserting the U-shaped core 1
1 is molded.

At this time, the first lower mold pressing surface 33a and the second lower mold pressing surface 33b of the lower mold 33 are opposite to the upper mold pressing surface 32a of the upper mold 32.
is configured to double-act and operate, and the center magnetic leg 12 is molded approximately at the center of the right front side of the yoke portion 15, and the side magnetic legs 13 are molded.

Note that when iron powder is used as the magnetic material, a powder magnetic core is formed by pressure molding, and when ferrite powder is used, a binder is added to the ferrite powder and granulated. A ferrite core is formed by pressure molding and further firing.

(Problems to be Solved by the Invention) However, according to the above-mentioned conventional method for manufacturing a U-shaped core, the U-shaped core configured so that the coil bobbin can be efficiently housed and made low in profile cannot be processed. When forming by pressure pressing, a double-acting press device must be used as the pressure press device, which makes it difficult to mold the magnetic material to a uniform density, and also makes it difficult to mold the magnetic material to a uniform density. There was a problem that cracks might occur.

Further, the double-acting press device is large and has complicated operation control, so the molding speed is slow and it is unsuitable for mass production.

Furthermore, in the manufacturing method using the double-acting press device, when U-shaped cores are brought into contact with each other to form a choke coil, etc., it is usually necessary to polish the contact surfaces of each core. However, there was a problem in that the surface polishing step was added.

The present invention has been made in view of the above circumstances, and has a U-shaped structure designed to effectively utilize the dimensions of each part through a simple manufacturing process without using large-scale molding equipment that is difficult to control. The present invention provides a method for manufacturing a U-shaped core.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a central magnetic leg,
A method for manufacturing a U-shaped core comprising a side magnetic leg arranged parallel to the side magnetic leg, and a yoke portion that connects one end side of the center magnetic leg and one end side of the side magnetic leg to each other, wherein a side column; The common column is formed by molding a magnetic material into an L-shape having a common column to which one end of the side column is connected, and cutting the L-shaped surface of the molded body into a plurality of parts. The above object is achieved by forming the central magnetic leg in the magnetic head and using the side pillars as the side magnetic legs.

In addition, the present invention molds a magnetic material into an L-shape having a side pillar and a common pillar to which one end of the side pillar is connected, and has a plurality of convex portions on the L-shaped surface of the molded body. By performing cutting to form a central magnetic leg on the common column and using the side columns as side magnetic legs, the above object is achieved.

(Function) In the present invention, the magnetic material is
By molding the molded body into an L-shape having a side pillar and a common pillar to which one end of the side pillar is connected, and cutting the molded body into a plurality of parts, the central magnetic A U-shaped core can be manufactured that includes a leg, a side magnetic leg arranged parallel to the leg, and a yoke portion that connects one end side of the center magnetic leg and an end side of the side magnetic leg to each other. .

Further, in the present invention, the U-shaped core is manufactured by molding a magnetic body into the above-described shape and cutting the molded body so as to form a plurality of convex portions on the L-shaped surface. I can do it.

In addition, since the U-shaped core is manufactured by molding the magnetic material into an L-shape using a small and simple device such as a single-acting press, and cutting the bent shape, the double-acting There is no need to use large and complicated control devices such as mold braces.

Further, in the U-shaped core manufactured by the above manufacturing process, the height of the central magnetic leg is formed to be lower than the height of the side magnetic legs, so that when the coil bobbin is fitted to the central magnetic leg, ,
The winding width of one coil of the coil bobbin does not protrude beyond the height of the side magnetic leg.

Furthermore, according to the manufacturing process, when cutting is performed to form a plurality of convex portions on the L-shaped surface of the curved molded body, the U-shaped cores manufactured by the present manufacturing method, etc. In combination, it is possible to simultaneously perform surface polishing of the contact surfaces that constitute choke coils and the like.

(Example) Embodiments of the present invention will be described in detail based on the drawings.

FIG. 1(a) is a perspective view showing an embodiment of the molding process according to the method for producing an E-shaped core of the present invention, and FIG. 1(b) is an L-shaped molded member formed by the molding process according to the same embodiment. FIG. 1(c) is a perspective view showing an example of the cutting process according to the same example, and FIG. 1(d) shows a U-shaped core formed by the manufacturing method according to the same example. A perspective view, FIG. 2(a) is a U manufactured by the manufacturing method according to the same example.
A front view showing the mold core, FIG. 2(b) is a sectional view showing the XX cross section of the U-shaped core manufactured by the manufacturing method according to the same example, and FIG. 3 is a U-shaped core according to the same example. FIG. 4(a) is a perspective view showing a cutting example of another manufacturing method according to the present invention, and FIG. 4(b) is a top view showing a choke coil constructed by FIG. 5(a) is a plan view illustrating a state in which the mold cores are combined, FIG. FIG. 6(a) is a plan view illustrating a state in which the related U-shaped cores are combined, FIG. 6(a) is a perspective view showing an example of the cutting process of another manufacturing method related to the present invention, and FIG. 6(b) is an example of the same implementation. A perspective view of an example U-shaped core is shown in each case.

As shown in FIG. 1(a), approximately in the center of the formwork 51,
An L-shaped hole 51a is formed by molding or the like, and the L-shaped hole 51a has a female shape.

From below the L-shaped hole 51a of the formwork 51, the L-shaped hole 51a
A lower mold 53 having the same shape as a is used as a male mold, and its upper part is inserted as shown by arrow 1 in the figure.

The curved hole 51a is filled with granulated powder 54 made of a magnetic material.

From above the L-shaped hole 51a filled with the granulated powder 54,
An upper mold 52 having the same shape as the mold hole 51a and the lower mold 53 serves as a male mold, and its lower part is inserted therein as shown by the arrow ■ in the figure.

Therefore, the single-acting breath device 55 configured as described above
The granulated powder 54 filled in the L-shaped hole 51a of the upper die 5
2 upper mold pressure surface 52a and lower mold pressure surface 53a of the lower mold 53
is pressurized and molded into an L-shaped molded member 61 shown in the first part (g(b)).

The curved molded member 61 is formed into a wedge shape, including a side column 63 and a common column 62 to which one end of the side column 63 is connected. Lower mold 5
Since the lower mold pressurizing surface 53a of No. 3 is flat-processed, the upper and lower surfaces of each of the side pillars 63 and the common pillar 62 of the molded member 61 are formed on the same plane.

Further, in the die-molded member 61, the common column 62 is formed wider than the side column 63 by the single-acting press device 55.

Next, as shown in FIG. 1(c), a grinder device 73 in which a disc-shaped grinder 71 made of an abrasive material or the like is attached to a rotating shaft 74 is driven by an arrow mark The molding member 6 is rotated in the direction of
1 is moved in the direction indicated by the arrow ■ in the figure by a moving mechanism (not shown).

Therefore, the common column 62 of the curved molded member 61 is the side column 63.
along the inner edge of the grinder device 73, the cutting depth is determined by the cutting width of the cutting surface 71a of the disc type grinder 71 and the installation height of the rotary shaft 74, as shown in FIG. 1(d). By forming the cutting grooves 86, a -U-shaped cocoa 81 is formed.

In the U-shaped core 81, the side column 63 becomes a side magnetic leg 83, the upper part of the common column 62 becomes a center magnetic leg 82, and the lower part of the common column 62 connects the center magnetic leg 82 and the side magnetic leg 83. The yoke portion 85 is configured to

As shown in FIG. 2(b), the U-shaped core 81 is molded into the molded member 61, so that the height Hl of the center magnetic leg 82 becomes equal to the height H2 of the side magnetic legs 83. It is shorter than the.

That is, as shown by imaginary lines in FIG. 1(d) and FIG. 2(b), a coil bobbin 88 made of a coil or the like wound with enameled wire or the like is fitted onto the central magnetic leg 82. When the upper part of the winding of the coil bobbin 88 is
can be prevented from protruding beyond the height H2.

Further, the choke coil 90 shown in FIG. 3 is constructed by combining the U-shaped core 81 manufactured by the manufacturing method of this embodiment with another U-shaped core, and by fitting the coil bobbin 88 into each central magnetic leg. It is configured with a

According to this embodiment, the small and simple single-acting breath device 5
5, the magnetic material is molded into the L-shaped molded member 61, and the U-shaped molded member 61 is cut, thereby making it possible to manufacture the U-shaped fan 81, thereby eliminating the need for a complicated manufacturing process.

In addition, in manufacturing the U-shaped core 81 that efficiently accommodates the coil bobbin and has a low profile that can be mounted on an electronic circuit board, etc., there is no need for a double-acting brace device that is large and has complicated operation control. In addition, the magnetic material is pressure-molded to have a uniform density, the molding speed is improved, mass production is possible, and micro-cracks and the like occurring in the U-shaped core 81 can be prevented.

Further, in the U-shaped core 81 manufactured by the above manufacturing process, the height Hl of the central magnetic leg 82 is formed to be lower than the height H2 of the side magnetic leg 83, so that the coil bobbin 88 is 82, the coil winding width of one side of the coil bobbin 88 can be prevented from protruding beyond the side magnetic leg 83.
It is possible to stably mount choke coils with built-in components.

Next, another embodiment of the present invention will be described with reference to FIG.

In this embodiment, the same parts as in the previous embodiment are given the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 1(a), granulated powder 24 made of a magnetic material is molded into an L-shaped molded member 61 by a single-acting press 55. As shown in FIG.

As shown in FIG. 4(a), the grinder device 93 includes a first abrasive grinder 92a and a second abrasive grinder 92b, which are connected to both end surfaces of the disk-type grinder 71, and which rotate It is configured by being pivotally attached to a shaft 74.

At this time, the first abrasive grinder 92a and the second abrasive grinder 92b are connected to the first disk-type grinder 71 and the second abrasive grinder 92b in accordance with the cutting depth determined by the installation height of the rotating shaft 74 of the grinder device 93. It is formed to have a diameter smaller than that of the disc type grinder 72, and is adapted to perform surface polishing of the upper surfaces of the common column 62 and the side columns 63.

A cutting groove 87 is formed by the cutting process by the grinder device 93, and the common polished surface 62a of the common column 62 and the side column polished surface 63a of the side column 63 are each surface polished to form a U-shaped core 91. is formed.

In the U-shaped core 91, the common column 62 is connected to the central magnetic leg 8.
2, the side column 63 becomes the side magnetic leg 83, the common ground surface 62a becomes the center magnetic leg ground surface 82a, and the side column polished surface 63a becomes the side magnetic leg ground surface 83a.

The U-shaped core 91 and other U-shaped cores are combined, and a coil bobbin 88 is fitted to each central magnetic leg to form a choke coil 100 as shown in FIG. 4(b).

At this time, the choke coil lOO is attached to the center magnetic leg polished surface 82a and the side magnetic leg polished surface 83a of the U-shaped core 91, and to the other U-shaped core 91.
The corresponding surfaces of the mold core are brought into contact with each other, and the center magnetic leg polishing surface 82a and the side magnetic leg polishing surfaces 83
Since a and the corresponding surface are surface-polished, the corresponding surfaces can be brought into close contact with each other, and the choke coil 100 can be assembled reliably without degrading its magnetic properties. I can do it.

Furthermore, according to the manufacturing process, when cutting is performed to form a plurality of convex portions on the L-shaped surface of the molded body, the central magnetic legs and the pair of Since surface polishing of the contact surfaces of the side magnetic legs where the U-shaped cores and the like are combined can be performed simultaneously, the surface polishing process for the corresponding contact surfaces can be omitted.

Next, another embodiment of the present invention will be described with reference to FIG.

Similarly, in this embodiment, the same parts as in the previous embodiment are denoted by the same reference numerals, and the explanation thereof will be omitted.

L-shaped molded member 61 molded in FIG. 1(a)
As shown in FIG. 5(a), the grinder device 9
The first polishing grinder 92a of the first polishing grinder 92a is cut by a grinder device 103, which is replaced by a cutting grinder 102 having a larger diameter than the first polishing grinder 92a, thereby forming a U-shaped core Lot.

At this time, the common column 6 is cut by the central cutting grinder 103.
The upper part of 2 is cut to form a central magnetic leg 1 whose height is lower than that of the common column 6.
06, and the upper surface of the center magnetic leg 106 is a cut surface 106a of the center magnetic leg, which is surface-polished at the same time as cutting.

At this time, in the U-shaped core 101, the common column 62 becomes the center magnetic leg 106, the side columns 63 become the side magnetic legs 83, and the common column cut surface 62b becomes the center magnetic leg cut surface 106a.
Thus, the side pillar polished surface 63a becomes the side magnetic leg polished surface 83a.

The U-shaped core 101 and other U-shaped cores are combined, and a coil bobbin 88 is fitted into each central magnetic leg to form a choke coil 110 as shown in FIG. 5(b).

At this time, the center magnetic leg 106 of the U-shaped core 101 and the other
A central air gap 105 is provided between the opposing central magnetic legs of the mold core.

The central gap 105 can be formed by arbitrarily providing a gap.
The magnetic characteristics of the choke coil 110 can be adjusted.

Therefore, according to this embodiment, the central gap 105 for magnetically adjusting the choke coil 110 can be formed simultaneously with the cutting process, and surface polishing can also be performed.

Next, other embodiments according to the present invention are shown in FIGS. 6(a) and (
This will be explained with reference to b).

Similarly, in this embodiment, the same parts as in the previous embodiment are denoted by the same reference numerals, and the explanation thereof will be omitted.

If a curved surface processing portion 115 is provided on the ridge of the disc type grinder 71 of the grinder device 73, the molded member 61 is cut by the grinder device 73. A curved portion 116 is formed at 86 .

According to the U-shaped core 111 in which the curved portion 116 is formed,
- It is possible to prevent layer microcracks from occurring.

Further, the disc type grinder 71 of the grinder device 73
Taper processing may also be applied to.

Note that when iron powder is used as the magnetic material, a powder magnetic core is formed by pressure molding, and when ferrite powder is used, a binder is added to the ferrite powder and granulated, followed by pressure molding. A ferrite core is formed by molding and firing.

In addition, in this example, in order to pressurize the granulated powder,
Although a single-acting press machine is used, the present invention is not limited to this, and for example, a wet extrusion molding machine or the like may be used.

Further, in this embodiment, a rotating disc-shaped grinder device is used for cutting, but the present invention is not limited to this, and for example, a rotating belt-shaped sander or the like may be used.

(Effects of the Invention) Since the method for manufacturing a U-shaped core according to the present invention is configured as described above, it has the following effects.

(1) A U-shaped core is formed by molding a magnetic material into an L-shaped molded member using a small and simple single-acting press, etc., and cutting the L-shaped surface of the molded body into multiple parts. Since it can be manufactured, a complicated manufacturing process is not necessary, and the manufacturing process can be simplified, which is an excellent effect.

(2) In addition, a U-shaped core can be manufactured by molding a magnetic material into an L-shaped molded member and cutting the molded body to form a plurality of convex portions on the L-shaped surface. Therefore, there is an excellent effect that a complicated manufacturing process is unnecessary and the manufacturing process can be simplified.

(3) In addition, the E-shaped core, which accommodates the coil bobbin efficiently and is formed to have a low profile so that it can be mounted on an electronic circuit board, etc., is not molded using a double-acting press device that is large and has complicated operation control. , the magnetic material is molded into an L-shaped molded member using a single-acting press machine, and the U-shaped core is manufactured by cutting, so the magnetic material is pressure-molded with uniform density, and the molding It has excellent effects in that the speed is improved, mass production is possible, and microcracks etc. caused by pressurization by a double-acting press device can be prevented.

(4) In addition, in the U-shaped core manufactured by the above manufacturing process, the height of the central magnetic leg is formed to be lower than the height of the side magnetic legs, so that the coil bobbin is fitted into the central magnetic leg. When the coil winding width of one side of the coil bobbin is installed can be prevented from protruding beyond the height of the side magnetic leg, it is possible to stably mount a choke coil or the like in which the U-shaped core is incorporated on an electronic circuit board or the like. It has the excellent effect of being able to

(5) Furthermore, when using the above-mentioned U-shaped cores etc. in combination, it is necessary to perform surface polishing on the contact surfaces of the cores, but according to the above-mentioned manufacturing process, it is possible to When performing cutting to form a plurality of convex portions on the L-shaped surface of the molded body, surface polishing of the corresponding contact surfaces can be performed at the same time, so the surface polishing step can be omitted. This has excellent effects in that the assembly can be performed reliably and deterioration of magnetic properties can be prevented.

[Brief explanation of drawings]

FIG. 1(a) is a perspective view showing an embodiment of the molding process according to the method for producing an E-shaped core of the present invention, and FIG. 1(b) is an L-shaped molded member formed by the molding process according to the same embodiment. FIG. 1(c) is a perspective view showing an example of the cutting process related to the same example, and FIG. 1(d) is a perspective view showing a U-shaped core formed by the manufacturing method related to the same example. FIG. 2 (al is a front view showing a U-shaped core manufactured by the manufacturing method according to the same example, and FIG. 2<b) is a U-shaped core manufactured by the manufacturing method according to the same example. FIG. 3 is a plan view showing a choke coil constituted by a U-shaped core according to the same embodiment, and FIG. 4(a) is a cutting diagram of another manufacturing method according to the present invention. FIG. 4(b) is a perspective view showing a processing example; FIG. 4(b) is a plan view illustrating a state in which U-shaped cores according to the same example are combined; FIG. 5(a) is another manufacturing method according to the present invention. FIG. 5(b) is a plan view illustrating a state in which U-shaped cores according to the same embodiment are combined. FIG. 6(a) is a perspective view showing an example of cutting processing according to the present invention. A perspective view showing an example of the cutting process of the method, FIG. 6(b) is a perspective view showing a U-shaped core according to the same example, FIGS. 7 and 8 are perspective views showing a conventional U-shaped core, Fig. 9(a) is an explanatory diagram illustrating a method of manufacturing a U-shaped core using a conventional single-acting type brace, Fig. 9(b) is a cross-sectional view showing the A-A cross section of the single-acting type press, Fig. 10 (a) is an explanatory diagram illustrating a method of manufacturing a U-shaped core using a conventional double-acting type brace, and FIG. 62 ・ 71 ・ 73 ・ 81 ・ 82 ・ 85 ・ Common column, 63... side column, disk type grinder, grinder device U-shaped core, central magnetic leg, 83 ・ yoke part.・Side magnetic legs,

Claims (2)

[Claims] (1) A central magnetic leg, side magnetic legs arranged parallel to this,
A method for manufacturing a U-shaped core comprising: a yoke portion that connects one end side of the center magnetic leg and one end side of the side magnetic leg; a side column; and a common column to which the one end portion of the side column is connected. and,
By molding a magnetic material into an L-shape having
A method for manufacturing a U-shaped core, characterized in that the U-shaped core is manufactured by forming the central magnetic leg on the common column and using the side columns as the side magnetic legs. (2) A magnetic material is molded into an L-shape having a side pillar and a common pillar to which one end of the side pillar is connected, and a plurality of convex portions are formed on the L-shaped surface of the molded body. A method for manufacturing a U-shaped core, characterized in that the U-shaped core is manufactured by cutting the common column to form a central magnetic leg and using the side columns as side magnetic legs.