JP2010171361A - Method of manufacturing magnetic core and method of manufacturing inductor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a magnetic core expanding the sharing of manufacturing equipment without needing to use an expensive facility for compacting; and to provide a method of manufacturing an inductor using the same. <P>SOLUTION: The method includes: a step of providing a laminate 7 including unbaked first magnetic sheet 4 and second magnetic sheet 6, and an unbaked holder sheet 1 with magnetic past 5 filled in holes 3; and a baking step of eliminating the holder sheet 1 by baking the laminate 7. Thus, a drum core can be provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a magnetic core of a winding type inductor, and a method for manufacturing an inductor using the same.

  Inductor components are widely used in electric circuits, and winding inductors in which a conductor is wound around a core made of a magnetic material are also widely known. As a core of this winding type inductor, a winding part which is a part of the core and is a part around which a conductor is wound, a drum core having flanges at both ends of this winding part, or a flange only at one end of the winding part There are known a T-type core provided, an E-type core having a shape in which one end of three columnar cores having a winding portion at the center is connected.

  Among such magnetic cores, a widely known method for manufacturing a drum core is to form a ferrite powder, which is a magnetic material, into a cylindrical shape, and then cut the portion corresponding to the winding portion with a diamond grindstone or the like. (Refer to the item “Prior Art” of Patent Document 1 and FIG. 5).

In the case of a T-shaped core, a method is known in which magnetic powder is formed into a T-shape with a mold (see Patent Document 2). Also, the E-type core is manufactured in the same manner as the T-type core manufacturing method.
JP 11-251150 A JP 2005-302926 A

  In the manufacturing method of the magnetic core related to the drum core described in Patent Document 1 and the manufacturing method of the magnetic core related to the T-type core described in Patent Document 2, it is essentially difficult to share equipment necessary for manufacturing, Individual facilities were required for each manufacturing method.

In any of the manufacturing methods, a powder molding technique is used in which a magnetic powder is molded into a cylindrical shape or a T shape using a mold, and the pressure required for this molding is 9.8 ×. A high pressure of 10 ⁷ Pa (1000 kgf / cm ² ) or more was required, and equipment and molds were also expensive. In the case of a drum core, the above-mentioned expensive mold is required every time the outer shape of the flange and the outer dimension between the two flanges are different, and in the case of the T-type core, the outer shape is different. Met.

  The present invention solves the above-described conventional problems, and it is not necessary to use expensive equipment for powder molding, and a manufacturing method of a magnetic core capable of broadening the sharing of manufacturing equipment and the same The present invention provides a method of manufacturing an inductor using the above.

  In order to achieve the above object, the present invention has the following configuration.

  The invention according to claim 1 is a step of obtaining a laminate including an unsintered magnetic sheet and an unsintered holder sheet in which a magnetic paste or magnetic powder is put inside a hole; And a firing step in which the body sheet is fired to dissipate or decompose the holding sheet. According to this method, the present invention does not require powder molding, and has the effect that a plurality of types of magnetic cores can be manufactured with relatively simple equipment.

  The invention described in claim 2 is a dividing step of dividing the laminate into individual laminates after the step of obtaining the laminate, particularly in the step of obtaining the laminate. According to this method, it is possible to obtain a plurality of magnetic cores from one large laminated body, and there is an effect that the productivity is excellent.

  In the invention according to claim 3, particularly in the step of obtaining the laminate, the magnetic sheet has a first magnetic sheet on one surface of the holder sheet and the other surface of the holder sheet. The second magnetic sheet is disposed on the surface, and according to this method, the drum-type magnetic core can be manufactured with relatively simple equipment.

  The invention according to claim 4 is particularly advantageous in that the holder sheet is a mixture of carbon and resin slurry, and according to this method, there is an effect that there is little variation in dimensions due to firing.

  The invention according to claim 5 is an embodiment in which a step of winding a conducting wire around a part of the magnetic core is added after the firing step of the manufacturing method of the magnetic core. Therefore, it is possible to manufacture an inductor corresponding to a plurality of types of magnetic cores with simple and simple equipment.

  As described above, the magnetic core of the present invention is a process for obtaining a laminate including an unsintered magnetic sheet and an unsintered holder sheet in which a magnetic paste or magnetic powder is placed inside the hole; And a firing step in which the laminate is fired to dissipate or decompose the holding sheet, and there is no need to perform powder molding, and a plurality of types of magnetic cores can be formed with relatively simple equipment. There is an effect that it can be manufactured.

  A magnetic core manufacturing method and an inductor manufacturing method using the same according to an embodiment of the present invention will be described below with reference to the drawings.

  1 to 4 are sectional views showing a method for manufacturing an inductor according to an embodiment of the present invention, and FIGS. 5 to 8 are perspective views showing a method for manufacturing the inductor. Among these, FIG. 1 to FIG. 4A and FIG. 5 to FIG. 8A are views showing a method for manufacturing a magnetic core.

  In FIG. 1 (a) and FIG. 5 (a), the holder sheet 1 is a sheet made of a resin, specifically, butyl acetate as a solvent, carbon as a filler, butyral resin as a binder, and a plasticizer. A sheet is formed using the slurry. This holder sheet 1 is formed on a film 2. The film 2 is preferably made of a material that has adhesiveness to the holder sheet 1 and can be easily peeled off. For example, PET (polyethylene terephthalate) or PPS (polyphenylene sulfite) can be used.

  In FIG. 1B and FIG. 5B, a process of forming the holes 3 in the holder sheet 1 and the film 2 is shown. The hole 3 may be formed by a mechanical force such as a punch or by irradiating a laser. When forming with a laser, the freedom degree of the shape of the hole 3 can be made high. In the present embodiment, the holes 3 are formed in a square shape using a laser method.

  FIG. 1C and FIG. 5C show a process of superimposing the holder sheet 1 formed on the film 2 on the first magnetic sheet 4 so that the film 2 is positioned on the upper side. As the first magnetic sheet 4, a ferrite sheet can be used.

  FIG. 2A and FIG. 6A show a process of putting the magnetic paste 5 in the hole 3. As the magnetic paste 5, a paste of ferrite is used. In forming the paste, it is preferable to use the same binder or plasticizer as that of the holder sheet 1 because variations in dimensional changes during firing can be suppressed. In addition, it can replace with the magnetic body paste 5, and can also use magnetic body powder. Ferrite powder can be used as the magnetic powder.

  In FIG. 2B and FIG. 6B, the state where the film 2 is peeled from the holder sheet 1 is shown. At this time, the magnetic paste 5 may protrude above the upper surface of the holder sheet 1, but is flattened by pressing with a rigid body from above.

  2 (c) and 6 (c) show a step of arranging the second magnetic sheet 6 on the upper surface of the holder sheet 1. FIG. The material of the second magnetic sheet 6 can be the same material as that of the first magnetic sheet 4. Through the steps so far, the laminate 7 including the first magnetic sheet 4 and the second magnetic sheet 6, and the unfired holder sheet 1 in which the magnetic paste 5 is put in the hole 3 is formed. Obtainable.

  FIG. 3A and FIG. 7A show a process of forming the external electrode 8 on the upper surface of the second magnetic sheet 6. As a manufacturing method of the external electrode 8, a printing method can be used, but a thin film method or the like may be used. As the material of the external electrode 8, Ag, Cu, AgPd, or the like can be used.

  In FIG. 3B and FIG. 7B, an imaginary line dividing line 9 showing a dividing position for dividing into individual magnetic cores is shown. At this position, it is divided into pieces. As a dividing method, a method such as dicing or cutting can be used.

  FIG. 3C and FIG. 7C show a state where the image is actually divided into pieces. In FIG. 3, it is divided into three in the horizontal direction of the paper, and FIG. 7 shows a total of four divided into two in the horizontal direction of the paper and two in the longitudinal direction of the paper.

  4 (a) and 8 (a) show a state after firing the laminated body 7 divided into pieces in the state of FIGS. 3 (c) and 7 (c). The first magnetic sheet 4, the magnetic paste 5, and the second magnetic sheet 6 shown in FIGS. 3C and 7C are integrated by firing to form the magnetic core 10. The magnetic core 10 includes a flange 10b and a flange 10c at both ends of the winding portion 10a. The winding part 10a corresponds to the magnetic paste 5 before firing, the flange 10b corresponds to the second magnetic sheet 6 before firing, and the flange 10c corresponds to the first magnetic sheet 4 before firing. Moreover, the support body sheet | seat 1 is lose | disappeared by baking. Ideally, the holder sheet 1 disappears completely. However, even if a part of the substance constituting the holder sheet 1 remains, the amount of the substance may not be affected if the amount is small. The firing temperature is 850 to 1100 ° C. This firing temperature is required to be a temperature at which the holder sheet 1 can be eliminated and at which the first magnetic sheet 4, the magnetic paste 5 and the second magnetic sheet 6 can be sintered. It is done. Further, when the external electrode 8 is formed by a printing method, it is required that the temperature be such that the external electrode 8 can be sintered.

  4 (b) and 8 (b), the flange electrode 11 is provided on a part of the side surface of the flange 10b. The manufacturing method is a printing method or a thin film method, and a known manufacturing method is applied. Can be manufactured. In the case of forming by the printing method, if the conductive paste is applied by printing after the step of dividing into individual pieces of FIG. 3 (c) and FIG. 7 (c), FIG. 4 (a) and FIG. This conductor paste can be sintered in the firing step. The coil conductor 12 is obtained by winding a conductor around the winding portion 10a. As the winding method of the coil conductor 12, edgewise winding or α winding can be selected as necessary. The surface of the coil conductor 12 is insulated except for the portion connected to the flange electrode 11.

  The magnetic core and inductor manufactured as described above do not need to be powder-molded by putting magnetic powder in a mold and hardened at high pressure, and can be manufactured with simple equipment.

Here, the material of the holder sheet 1 will be described. As already described, the holder sheet 1 is formed by using butyl acetate as a solvent, carbon as a filler, butyral resin as a binder, and a plasticizer slurry. However, as the holder sheet 1, materials other than these can be selected from the viewpoint that they can be eliminated by oxidation or chemical reaction in the firing step. The binder is not limited to the butyral resin used in the embodiment, and an acrylic resin can also be used. As the filler, not only resin-based organic fillers such as acrylic beads and urethane beads, but also inorganic fillers including ceramics such as alumina (Al ₂ O ₃ ) and zirconia (ZrO ₂ ) can be used. . For example, when a ceramic-based inorganic filler is used, the filler remains without disappearing in the firing step, but the resin that is the main component of the retainer sheet 1 disappears by the firing step and the retainer. Sheet 1 is broken down into granules. This granular residue is a ceramic inorganic filler, but this residue is very fragile and can be easily removed by blowing air or washing with water. When an inorganic filler such as alumina is used, the firing temperature in the firing step needs to be a temperature at which alumina or the like is not sintered. In the embodiment, butyl acetate is used as a solvent. However, the present invention is not limited to this, and water may be used as long as sheet forming is possible. Further, the holding sheet 1 is not limited to a resin as a main component, and for example, paper can be used.

  FIG. 9 is a diagram showing variation in dimensions due to the material of the holder sheet and firing in an embodiment of the present invention. The material of the holder sheet 1 is butyl acetate as a solvent, butyral resin is used as a binder, and carbon is used as a filler. Similarly, butyl acetate is used as a solvent, butyral resin is used as a binder, and acrylic beads are used as fillers. Experiments were conducted on three types, one using the paper and one using paper as the holder sheet 1. In addition, an experiment is performed on 10 samples for each material. The dimension measures the height of the coil | winding part 10a, ie, the distance between the flange 10b and the flange 10c. The vertical axis of FIG. 9 is a coefficient of variation. For each material, an average value of dimensions after firing is calculated, and the average value after subtracting the dimensions after firing of each sample by this average value is further calculated. Divided. In addition, the dimension before baking of each sample is set so that it may become the same dimension for every material.

  Although any material shown in FIG. 9 is used for the holder sheet 1, the drum core can be manufactured, but the variation in dimensional change is the smallest when carbon is used for the filler, and then acrylic beads are used. Followed by the one using paper. The reason for the large variation when using paper seems to be because when the paper is heated, the fiber of the paper is unwound and expands in the thickness direction of the paper, and the variation in the expansion of the paper at this time is large. . In addition, when acrylic beads are used, softening occurs before the acrylic disappears, and it is thought that expansion occurs at this time, but the variation in shape change due to the expansion is smaller than that of paper and larger than that of carbon. I think that. In the case of using carbon, it is considered that carbon does not undergo a particularly large expansion and eventually becomes carbon dioxide, which is a gas combined with oxygen. Further, in the case of carbon, after the resin such as butyl acetate as the solvent of the holder sheet 1 or the butyral resin as the binder is burnt down by firing, the burning of the carbon is started. And the disappearance temperature of the plasticizer and the disappearance temperature of the binder and the plasticizer in the magnetic paste 5 become the same temperature, so that the carbon in the holder sheet 1 is being sintered while the magnetic paste 5 is being sintered. Since disappears, it seems that variation in dimensions after firing is reduced.

  In addition, although the manufacturing method of the magnetic body core of this Embodiment was mentioned taking the drum core as an example, it is applicable also to the manufacturing method of the magnetic body core of another shape. For example, if the second magnetic sheet 6 is formed without being arranged, it is possible to manufacture a “T-shaped core” in which a flange is formed only on one of the winding portions 10a. In this case, the external electrode 8 needs to be formed on the first magnetic sheet 4.

  Moreover, E type | mold core can be manufactured without arrange | positioning the 2nd magnetic body sheet 6 similarly to the method of manufacturing this T type | mold core. In this case, through-holes are also formed between the holes 3 shown in FIG. 1B, and the magnetic paste 5 is put in the additionally formed through-holes, so that the magnetic material is also formed outside the coil conductor 12. An E-type core having a body core can be obtained.

  Furthermore, it is possible to easily obtain a magnetic core having an integral closed magnetic circuit. In this case, it can be obtained by arranging the second magnetic material sheet 6 in the method for manufacturing the E-type core described above. However, in this case, the method of winding the conductor around the winding portion 10a is somewhat complicated.

  Furthermore, it can also be set as the structure which forms a magnetic gap. In this case, it is possible to form a non-magnetic sheet between the holding sheet 1 and the first magnetic sheet 4 that is excellent in close contact with these and does not disappear in the firing step. Or it is also possible to make it the structure which does not use the hole 3 formed in the support body sheet | seat 1 as a through-hole. In this case, an air gap is formed.

  Further, the electrical connection between the external electrode 8 and the coil conductor 12 is not limited to the configuration shown in FIG. 4B and FIG. 8B, and several variations are conceivable.

  Hereinafter, the configuration of variations of the electrical connection between the external electrode 8 and the coil conductor 12 will be described.

  FIG. 10 is a perspective view of a first variation of the inductor according to the embodiment of the present invention, and FIG. 11 is a sectional view thereof.

  10 and 11, the structure of the flange 10b is such that the two corners are cut. This is a so-called “C-chamfered” structure. And the corner electrode 13 for electrically connecting the external electrode 8 and the coil conductor 12 is formed in the part which gave this C chamfering. The corner electrode 13 can be formed by a known manufacturing method such as a printing method or a thin film method. By adopting such a configuration, the corner electrode 13 falls within the range in which the flange 10c is projected, so that the size is smaller than the configuration in which the flange electrode 11 is formed as shown in FIGS. 4B and 8B. be able to.

  FIG. 12 is a perspective view of a second variation of the inductor according to the embodiment of the present invention, and FIG. 13 is a cross-sectional view thereof.

  12 and 13, a via electrode 14 is formed on the flange 10b. As a method for forming the via electrode 14, a through hole is formed in the first magnetic sheet 4 in advance, and the through hole is filled with a conductive paste, and the first magnetic sheet 4 is formed as shown in FIG. What is necessary is just to use for the process of (c). In the case of such a configuration, the size can be reduced as in the case of FIGS.

  As the first magnetic sheet 4 and the second magnetic sheet 6, among ferrite, Ni—Zn, Ni—Cu—Zn, Mn—Zn, Ni—Mn—Cu—Zn, A ferrite such as Mg—Zn or Mg—Cu—Zn can be used. It is also possible to use a magnetic material other than ferrite.

  The material of the magnetic paste 5 can be the same material as the first magnetic sheet 4 and the second magnetic sheet 6 described above. The sheet 4 and the second magnetic sheet 6 can be made of a different material.

  Further, instead of manufacturing a plurality of magnetic cores at a time, only one magnetic core can be manufactured. In this case, in order to obtain the drum core, only one hole 3 is formed in the holder sheet 1 and the dividing step in FIG. 3C is omitted. It is better to manufacture a plurality of magnetic cores at once as in the embodiment.

  As described above, according to the present embodiment, a laminate including the unfired first magnetic sheet 4 and the unfired holder sheet 1 in which the magnetic paste 5 is placed inside the hole 3. 7 and a firing step in which the laminate 7 is fired to dissipate or decompose the carrier sheet 1, so there is no need to perform powder molding, and there are multiple types with relatively simple equipment The magnetic core can be manufactured.

  Further, in the step of obtaining the laminate 7, a plurality of holes 3 are formed, and further, after the step of obtaining the laminate 7, a dividing step of dividing the laminate 7 into individual pieces is added. A plurality of magnetic cores can be obtained from the laminate, and the productivity is excellent.

  Further, in the step of obtaining the laminated body 7, as the magnetic material sheet, the first magnetic material sheet 4 is provided on one surface of the holding material sheet 1, and the second magnetic material sheet 6 is provided on the other surface of the holding material sheet 1. Therefore, the drum-type magnetic core can be manufactured with relatively simple equipment.

  And since the process of winding a conducting wire around a part of the magnetic core 10 is added after the firing process of the manufacturing method of the magnetic core, an inductor corresponding to a plurality of types of magnetic cores 10 with relatively simple equipment is provided. Can be manufactured.

  The magnetic core and the inductor manufacturing method using the same according to the present invention are useful because it is not necessary to perform powder molding and a plurality of types of magnetic cores and inductors can be obtained with relatively simple equipment.

Sectional drawing which shows the manufacturing method of the inductor in one embodiment of this invention Sectional drawing which shows the manufacturing method of the inductor in one embodiment of this invention Sectional drawing which shows the manufacturing method of the inductor in one embodiment of this invention Sectional drawing which shows the manufacturing method of the inductor in one embodiment of this invention The perspective view which shows the manufacturing method of the inductor in one embodiment of this invention The perspective view which shows the manufacturing method of the inductor in one embodiment of this invention The perspective view which shows the manufacturing method of the inductor in one embodiment of this invention The perspective view which shows the manufacturing method of the inductor in one embodiment of this invention Figure showing variation in material and dimensions of holder sheet of same inductor The perspective view of the 1st variation of the inductor in one embodiment of the present invention Sectional drawing of the 1st variation of the inductor in one embodiment of this invention The perspective view of the 2nd variation of the inductor in one embodiment of this invention Sectional drawing of the 2nd variation of the inductor in one embodiment of this invention

DESCRIPTION OF SYMBOLS 1 Holding body sheet 2 Film 3 Hole 4 1st magnetic body sheet 5 Magnetic body paste 6 2nd magnetic body sheet 7 Laminated body 8 External electrode 9 Dividing line 10 Magnetic body core 10a Winding part 10b Flange 10c Flange 11 Flange electrode 12 Coil conductor 13 Corner electrode 14 Via electrode

Claims (5)

A step of obtaining a laminate including an unsintered magnetic sheet and an unsintered holder sheet in which a magnetic paste or magnetic powder is placed inside the hole;
A firing step in which the laminate is fired to dissipate or decompose the holder sheet into particles;
The manufacturing method of the magnetic body core provided with. In the step of obtaining the laminate, a plurality of the holes are formed,
Furthermore, the manufacturing method of the magnetic body core of Claim 1 which added the division | segmentation process divided | segmented into a laminated body of an individual piece after the process of obtaining a laminated body. In the step of obtaining the laminate, the magnetic sheet has a first magnetic sheet disposed on one surface of the holder sheet and a second magnetic sheet disposed on the other surface of the holder sheet. The method for producing a magnetic core according to claim 1, wherein the magnetic core is a product. The method of manufacturing a magnetic core according to claim 3, wherein the holding sheet is a resin slurry in which carbon is mixed. The inductor manufacturing method which added the process of winding conducting wire around a part of the said magnetic body core after the said baking process of the manufacturing method of the magnetic body core in any one of Claims 1-4.

Images