JP6456729B2 - Inductor element and manufacturing method thereof - Google Patents

Description

  The present invention relates to an inductor element used for a power supply circuit of an electronic device and the like, and a manufacturing method thereof.

  As an inductor element used in a power supply circuit of an electronic device such as a CPU (Central Processing Unit), a structure in which a conductor such as a coil is penetrated through a magnetic body, that is, a magnetic core is known.

  In Patent Document 1, Fe-Si soft magnetic alloy powder having a flat shape including at least one of Al and Cr and having an aspect ratio of 2 or more and having an insulating layer on the surface is used, and the flat direction of the soft magnetic alloy powder is used. Of the soft magnetic alloy powder passes through the inside of the dust core that is pressed and molded together with the binder so as to orient the powder in the direction perpendicular to the pressing direction. Inductors are disclosed in which conductors are arranged so that current flows in a direction perpendicular to the vertical direction.

  In Patent Document 2, a flat fitting portion of an inner conductor is inserted into a groove formed on one side surface of a magnetic core having a quadrangular cross section, and a closed magnetic circuit forming member is inserted into the groove from above. There is disclosed an inductor element in which a closed magnetic circuit forming member and a magnetic core form a closed magnetic circuit that surrounds a fitting portion of an internal conductor.

JP 2007-214425 A Japanese Utility Model Publication No. 63-6712

  Since the magnetic cores of Patent Document 1 and Patent Document 2 do not have elasticity, it is difficult to insert the conductor unless the cross-sectional area of the portion of the magnetic core where the conductor is inserted is larger than the cross-sectional area of the conductor. There is a risk of cracks and cracks. For this reason, the cross-sectional area of the portion where the conductor is inserted is formed larger than the cross-sectional area of the conductor, and a process such as positioning of the conductor is necessary, and there is a problem that the cross-sectional area of the conductor cannot be easily manufactured. There is a problem that increasing the size of the inductor increases the size of the inductor.

  In Patent Document 1, a plurality of relatively thin molded bodies are stacked in order to increase the magnetic powder filling rate, and a dust core is formed by bonding between them. There is a possibility that the superposition characteristics may be deteriorated due to the variation in groove shape caused by the difference in hardness from the layer and the deformation during reflow due to the difference in thermal expansion coefficient.

  Accordingly, an object of the present invention is to provide an inductor element that can be easily manufactured by suppressing cracks and the like of a magnetic core and a method for manufacturing the inductor element.

  In order to solve the above-described problems, in the present invention, a soft magnetic metal powder having a flat shape is bound by a binder component to provide a hole, and a groove formed in an elastic magnetic core is made of copper or aluminum. A conductor made of a wire is inserted. That is, since the magnetic core of the present invention is elastically deformable, it is possible to insert a conductor having the same or larger width as the formed groove portion, and can easily hold the conductor. Even if it receives a pressing force, it is hard to break. In addition, the cross-sectional area of the conductor can be increased while maintaining the dimensions of the inductor element.

  In addition, since the stacked parts are conventionally bonded with an adhesive having a different hardness from the molded body, the grooves cannot be formed with high accuracy, and superposition caused by internal stress due to differences in the dimensions of the grooves or differences in thermal expansion coefficients. Characteristic degradation can occur. However, the present invention can uniformly reinforce the strength of the magnetic core by impregnating the magnetic core with uniformly formed holes, and further impregnate the conductor with the resin. Since it uses, it can avoid the influence by the dimension variation of the groove part at the time of fixation.

  Furthermore, in the present invention, by providing the impregnation resin impregnated at least from the groove portion, the surface strength of the magnetic core is increased, and delamination, cracks, and the like can be suppressed.

  An inductor element according to the present invention includes a magnetic core having a groove, a conductor inserted in the groove, and an impregnating resin having an insulating property impregnated from at least the groove, and the magnetic core has a flat magnetic shape. Metal powder is bound by a binder component, the magnetic core has a void inside, and at least one groove is formed along the thickness direction of the soft magnetic metal powder in the magnetic core. The binder component and the impregnating resin are different components.

  Further, it is desirable that the impregnating resin in the inductor element of the present invention is filled in at least some of the holes.

  Further, in the inductor element of the present invention, at least a part of the groove other than the part where the conductor is disposed may be filled with a nonmagnetic material having an insulating property.

  Moreover, the both ends of the conductor of the present invention may be mounting terminals.

  The inductor element of the present invention further includes a terminal portion, and the terminal portion is electrically connected to both end portions of the conductor, respectively, and both end surfaces of the magnetic core or both end surfaces in the longitudinal direction of the conductor. A part of the side peripheral part connected to the both end faces may be fitted.

  In the inductor element of the present invention, the magnetic core includes two groove portions, a middle leg portion, a first outer leg portion, a second outer leg portion, the middle leg portion, and the first outer leg portion. A first E-type magnetic core and a second E-type magnetic core each having a plate portion that connects the leg portion and the second outer leg portion, the groove portion, the middle leg portion, and the first outer leg portion. The second outer leg portions may be arranged to face each other, and the conductor may wind the middle leg portion.

  The volume ratio of the holes in the inductor element of the present invention is preferably 10% by volume or more and 25% by volume or less of the volume of the magnetic core.

  The method of manufacturing an inductor element according to the present invention includes a soft magnetic metal powder having a flat shape and a magnetic layer made of a binder component, and the soft magnetic metal powder is bonded by the binder component to provide holes. A step of producing a laminated body, a step of forming a groove in the lamination direction of the laminated body and a step of forming a plurality of magnetic cores by cutting in the lamination direction of the laminated body, a step of inserting a conductor into the groove, After inserting the conductor, it has a step of impregnating resin from at least the groove.

  The inductor element manufacturing method according to the present invention may further include a step of filling the gap in the groove with an insulating nonmagnetic material after impregnating the resin.

  According to the present invention, since the magnetic core has elasticity, the conductor can be easily inserted into the groove portion, and at least the surface of the groove portion is impregnated with the resin, so that the bonding between the layers is strengthened and delamination or Cracks and the like can be suppressed.

  From the above, it is possible to provide an inductor element that can be easily manufactured by suppressing cracks in the magnetic core and a manufacturing method thereof.

1 is a perspective view showing an inductor element according to a first embodiment of the present invention. It is a figure which shows the inductor element by the 1st Embodiment of this invention, (a) is a side view, (b) is sectional drawing cut | disconnected by the AA 'line of Fig.2 (a), (c) is It is a bottom view. It is structure explanatory drawing of the magnetic core of the inductor element by the 1st Embodiment of this invention, and is a part of cross section cut | disconnected by the B-B 'line | wire of Fig.2 (a). It is a figure which shows an example of the manufacturing method of the inductor element by the 1st Embodiment of this invention, (a) is a perspective view which shows typically the cutting | disconnection of a laminated body, (b) is the cutting | disconnection of a groove part and a laminated body piece FIG. It is a figure which shows another example of the manufacturing method of the inductor element by this invention, and is a top view which shows typically the cutting | disconnection of a groove part and a laminated body. It is a perspective view which shows the inductor element by the 2nd Embodiment of this invention. It is a figure which shows the inductor element by the 2nd Embodiment of this invention, (a) is a side view, (b) is sectional drawing cut | disconnected by CC 'line of Fig.7 (a), (c) is It is a bottom view. It is a perspective view which shows the inductor element by the 3rd Embodiment of this invention. It is a figure which shows the inductor element by the 3rd Embodiment of this invention, (a) is a side view, (b) is sectional drawing cut | disconnected by the DD 'line | wire of Fig.9 (a), (c) is It is a bottom view. It is a figure which shows the inductor element by the 4th Embodiment of this invention, (a) is a perspective view, (b) is sectional drawing cut | disconnected by the E-E 'line | wire of Fig.10 (a).

  Hereinafter, embodiments of the present invention will be described in detail.

(First embodiment)
FIG. 1 is a perspective view showing an inductor element according to the first embodiment of the present invention. 2A and 2B are diagrams showing the inductor element according to the first embodiment of the present invention, in which FIG. 2A is a side view, FIG. 2B is a cross-sectional view taken along the line AA ′ in FIG. c) is a bottom view. FIG. 3 is an explanatory diagram of the structure of the magnetic core of the inductor element according to the first embodiment of the present invention, and shows a part of a cross section taken along the line BB ′ of FIG.

  As shown in FIGS. 1 to 3, the inductor element 100 of the present invention includes a magnetic core 1 and a conductor 2, and the magnetic core 1 is formed by binding a soft magnetic metal powder 4 having a flat shape with a binder component 5. doing.

  Further, the magnetic core 1 has holes 6 and forms grooves 3 along the thickness direction of the soft magnetic metal powder 4. A plate-like conductor 2 is inserted into the groove 3, and both end portions of the conductor 2 protrude from the side surface of the magnetic core 1. The conductor 2 protruding from the side surface is bent in the same direction along the side surface, and is further bent along the bottom surface of the magnetic core 1, and both ends of the conductor 2 are on the bottom surface side of the magnetic core 1. The mounting terminals 8 are formed.

  The magnetic core 1 is provided with an impregnating resin 7 having an insulating property impregnated from the surface of the groove 3. The impregnating resin 7 is impregnated from the surface of the magnetic core 1, and in the present embodiment, the holes 6 near the surface of the groove 3 and the surface of the magnetic core 1 are filled. Further, the impregnating resin 7 is formed from a component different from the binder component 5.

  Here, the void means a void portion inside the magnetic core that is at least partially surrounded by a soft magnetic metal powder and a binder component that binds the soft magnetic metal powder. Further, the pores are also filled with the impregnating resin.

  Further, in this embodiment, the impregnating resin 7 is impregnated from the surface of the magnetic core 1 and fills the air holes 6 inside the surface. Further, all the air holes 6 of the magnetic core 1 are impregnated. May be. Moreover, the impregnation resin 7 may be applied or filled only in the surface of the groove portion 3 and the air holes 6 inside the groove portion 3.

  Hereinafter, a method for manufacturing the inductor element 100 according to the present invention will be described.

  4A and 4B are diagrams showing an example of a method for manufacturing an inductor element according to the first embodiment of the present invention. FIG. 4A is a perspective view schematically showing cutting of the multilayer body, and FIG. 4B is a groove portion and the multilayer body. It is a perspective view which shows the cutting | disconnection of a piece typically.

  A soft magnetic metal powder having a flat shape is mixed with a binder to prepare a slurry, and the slurry applied by a die slot method or a doctor blade method is dried to volatilize the solvent to obtain the magnetic layer 9. The obtained magnetic layer 9 is laminated one or more, or the obtained magnetic layer 9 is cut into a desired size to form a plurality of magnetic layers 9, and the plurality of magnetic layers 9 are Laminate 10 is obtained by laminating one or a plurality of layers, pressing in the laminating direction, and heat-treating at a high temperature.

  Here, the flat soft magnetic metal powder can be produced, for example, by flattening the particulate soft magnetic metal powder using a ball mill. Since soft magnetic metal powder can obtain good magnetic properties, it is preferable to use an Fe-based alloy such as Fe-Si, Fe-Si-Al, or Fe-Si-Cr.

  The binder component that binds the soft magnetic metal powder is preferably composed mainly of silicon oxide, and such a binder component can be obtained by using a binder containing Si. For example, a methylphenyl silicone resin may be used as a binder when preparing a slurry. The coated slurry is heated to volatilize the solvent to produce a magnetic layer that is a material for the magnetic core. A plurality of the produced magnetic layers are laminated, pressed in the laminating direction and compressed, and then heated (for example, , 600 ° C.), a laminate is obtained.

  By performing heat treatment at a high temperature, the organic components of the methylphenyl silicone resin are decomposed, and the solid content of the methylphenyl silicone resin becomes a binder component composed of a glassy material mainly composed of silicon oxide, and the soft magnetic metal powder is Bind. That is, since the soft magnetic metal powder is bound by an inorganic material, the laminate produced in this way can withstand reflow at a high temperature of about 260 ° C.

  Moreover, since the organic component of the binder is lost due to the heat treatment at a high temperature, the binder is reduced in heat, and pores are formed inside the laminate. That is, the laminate includes soft magnetic metal powder, a binder component, and pores.

  The obtained laminated body 10 is cut | disconnected along the lamination direction, ie, the cutting part 11, and the several laminated body piece 12 is obtained. Next, the laminated piece 12 is cut along the laminating direction, that is, along the cut portion 13, and along the cut portion 14 so as to form a groove portion in the thickness direction of the soft magnetic metal powder. The core 1 and the E-type magnetic core 15 are obtained.

  Here, the cutting of the laminate and the formation of the groove may be performed using a known technique such as a dicing saw or a water jet.

  Moreover, there is no restriction | limiting in the shape of a groove part, You may form in a rectangle with a fixed width | variety, and you may form by connecting different widths. That is, when the width of the groove portion where the conductor is disposed is the same as the thickness of the conductor, the width of the groove portion where the conductor is not disposed is narrower than the width of the groove portion where the conductor is disposed. Also good. By forming the width of the groove portion where the conductor is not disposed narrower than the portion where the conductor is disposed, it is possible to suppress the conductor from dropping out of the groove portion.

  Next, as shown in FIG. 2, the conductor 2 is inserted into the groove 3 so that the axis of the conductor 2 is substantially the same as the central axis of the magnetic core 1. Both ends of the conductor 2 protruding from the side surface of the magnetic core 1 are bent in the same direction along the side surface, and further bent along the bottom surface of the magnetic core 1 to form the mounting terminals 8.

  For the magnetic core 1 according to the present embodiment, a conductor 2 having an insulating coating is used. Here, since the soft magnetic metal powder 4 is bound by the binder component 5 having insulating properties, it has a high electrical resistivity. Furthermore, when the laminated body 10 has an electrical resistivity of 10 kΩ · cm or more and has good insulation, the magnetic core 1 that is the laminated body 10 and the conductor 2 that does not have an insulating coating. It is good also as a structure which touches directly.

  In addition, the magnetic core 1 according to the present embodiment has high strength and has some elasticity. That is, the magnetic core 1 is formed so as to be elastically deformable, and the occurrence of cracks and the like can be suppressed even when a pressing force is applied.

  Therefore, it is possible to insert a conductor 2 that is the same as the width of the formed groove 3 or larger than the width of the groove 3, and the large conductor 2 having an increased cross-sectional area without changing the size of the magnetic core 1 is large. The inductor element 100 corresponding to the current can be obtained.

  Further, by allowing insertion of the conductor 2 that is the same as or larger than the width of the groove 3, the conductor 2 can be easily held by the pressing force of the inner wall of the groove 3 that has been elastically deformed. The displacement is suppressed and the positioning accuracy is improved. Moreover, since the process of positioning and fixing the conductor 2 can be reduced, the manufacturing process can be simplified and the cost can be reduced.

  Thus, in order to have high intensity | strength and elasticity, it is preferable that the volume ratio of the void | hole contained in a magnetic core is 10 volume% or more and 25 volume% or less. When the volume ratio is 10% by volume or more, the magnetic core has elasticity and can be easily processed in various ways. When the volume ratio is 25% by volume or less, the magnetic core can sufficiently contain soft magnetic metal powder.

  Here, the rubber hardness according to ISO7619-type D of the magnetic core 1 is 92 or more and 96 or less, and the magnetic core can be elastically deformed.

  Here, the desired volume ratio of the pores can be obtained by adjusting the amount of the binder when producing the slurry and the pressure when compressing the magnetic layer by pressurization.

  Further, the volume ratio of the pores means the volume ratio of the void portions of the pores not filled with the impregnating resin.

  Here, in this embodiment, after the conductor 2 is inserted into the groove 3, the mounting terminal 8 is formed by bending, but the present invention is not limited to this, and the bent conductor 2 is inserted into the groove 3. Also good.

  Next, the surface of the magnetic core 1 is immersed by immersing the groove portion 3 in a resin while leaving at least a part of the mounting surface of the mounting terminal 8 above the liquid level so that at least the mounting surface of the mounting terminal 8 is exposed and conductive connection is possible. The resin is impregnated into the pores 6 that are further inside, and the impregnating resin 7 is formed inside the surface of the magnetic core 1 and from the surface. The impregnating resin 7 has a component different from the binder component.

  In the present embodiment, the resin is immersed and impregnated in the resin while leaving at least a part of the mounting surface of the mounting terminal 8. However, the impregnation resin 7 is not limited to such immersion, and at least the surface of the groove 3 is filled with the impregnation resin 7. It only has to be formed. In this case, the resin may be impregnated by coating or filling the inside of the groove with the resin from the surface of the groove portion 3. That is, the surface of the magnetic core and the method of impregnating the resin from the surface are not limited, and the impregnated resin may be formed by a known method.

  By forming the impregnating resin 7 on the surface of the groove portion 3 and the inside thereof, the strength on the surface of the groove portion 3, that is, the surface strength is increased and the binding force between the magnetic layers 9 is improved. And cracks can be further suppressed. Moreover, since the binding force between the magnetic layers 9 is improved on the entire surface portion of the magnetic core 1 by forming the impregnating resin 7 on the surface of the magnetic core 1 and on the inside thereof, delamination and cracks can be further suppressed. .

  Here, the impregnating resin 7 may be an acrylic resin or polyolefin resin suitable for impregnation having a component different from the binder component 5. Further, since it is sufficient that the magnetic core 1 has elasticity when the conductor 2 is inserted into the groove 3, the hardness of the impregnating resin 7 is not limited, and the hardness of the magnetic core 1 is obtained by forming the impregnating resin 7. May be increased. That is, since the impregnating resin 7 is impregnated after the laminate 10 is produced, the impregnating resin 7 has a component that is essentially different from the binder component 5 that has been subjected to the above-described heat treatment at a high temperature (for example, 600 ° C.).

  Moreover, in this Embodiment, after cut | disconnecting a laminated body and obtaining a some laminated body piece, it cut | disconnected and groove | channel-formed further and obtained the magnetic core and the E-type magnetic core, However, it is not restricted to this. That is, the magnetic core and the E-type magnetic core may be manufactured by simultaneously cutting the stacked body and forming the groove portion without preparing the multilayer piece.

  In this embodiment, a plurality of E-type magnetic cores having a plurality of magnetic cores and two groove portions are produced from one laminated body by cutting and forming the groove portions, but the present invention is not limited to this. . That is, a plurality of magnetic cores having only one groove portion may be manufactured from one laminate, or a plurality of E-type magnetic cores may be manufactured.

  In the present embodiment, after the magnetic core and the E-type magnetic core are manufactured, the conductor is inserted into the groove portion. However, the present invention is not limited to this. That is, after forming a groove part in a laminated body piece, a conductor may be inserted and cut in a state where the conductor is inserted to produce a magnetic core.

  FIG. 5 is a view showing another example of the method for manufacturing an inductor element according to the present invention, and is a top view schematically showing the cutting of the groove and the laminated body. As shown in FIG. 5, after forming the groove part 18 in the laminated body 17, the conductor is inserted into the groove part 18, and after the conductor is inserted, it is cut along the cutting part 19 indicated by the broken line to obtain the magnetic core 20. Also good. In other words, the conductor may be inserted after the formation of the groove, and there is no limitation on the order of manufacture for cutting the laminate, forming the groove, cutting the laminate, and inserting the conductor into the groove. What is necessary is just to set suitably according to a specification.

  Further, a nonmagnetic material having insulating properties may be filled in the gap portion of the groove portion into which the conductor is inserted. For example, the groove part may be filled with the same resin as the impregnating resin, or a resin different from the impregnating resin may be filled into the groove part. When filling the same resin as the impregnating resin, after forming the impregnating resin, the same resin as the impregnating resin may be filled to form a nonmagnetic material, or at the same time as forming the impregnating resin, the nonmagnetic material May be formed. In addition, when a resin different from the impregnating resin is filled, after forming the impregnating resin, a nonmagnetic material may be formed by filling a resin different from the impregnating resin.

  In addition, the magnetic core is included in the magnetic core because it can improve the saturation magnetic flux density, relative magnetic permeability, and thermal conductivity of the magnetic core by increasing the filling rate of the soft magnetic metal powder, and further suppress the decrease in electrical resistivity. The volume ratio of the soft magnetic metal powder is preferably 55% by volume or more and 85% by volume or less. Further, in order to further increase the relative permeability of the magnetic core, it is more preferable that the soft magnetic metal powder is contained in an amount of 60% by volume or more and 70% by volume or less.

(Second Embodiment)
FIG. 6 is a perspective view showing an inductor element according to the second embodiment of the present invention. 7A and 7B are diagrams showing an inductor element according to a second embodiment of the present invention, in which FIG. 7A is a side view, and FIG. 7B is a cross-sectional view taken along the line CC ′ of FIG. c) is a bottom view.

  As shown in FIGS. 6 and 7, the inductor element 200 of the present invention includes a magnetic core 21, a conductor 22, a terminal portion 23, an insulating nonmagnetic material 24, and an impregnating resin (not shown). .

  The magnetic core 21 is formed by binding a soft magnetic metal powder having a flat shape with a binder component, has holes, and forms a groove in the thickness direction of the soft magnetic metal powder. A plate-like conductor 22 is inserted into the groove, and a gap portion of the groove where the conductor 22 is inserted is filled with a nonmagnetic material 24 having an insulating property.

  Both end portions of the conductor 22 and the terminal portion 23 are electrically connected to each other, and the terminal portion 23 is a side surface of the magnetic core 1 that is both end surfaces in the longitudinal direction of the conductor 22, and a side peripheral portion surrounding the side surface. Part of is fitted. The terminal portion 23 may be formed by plating the side surface of the magnetic core 21 and a part of the side peripheral portion surrounding this side surface, or by forming a metal powder such as silver paste or nano silver. Also good.

  Further, the conductor 22 is not limited to a plate shape made of a conductor, and a metal powder such as silver paste or nano silver may be used. In this case, after impregnating the resin from the surface of the groove part, after filling the non-magnetic material 24 other than the part where the conductor 22 is inserted in the groove part, that is, the conductor hole part to form the conductor hole part, What is necessary is just to pack metal powder, such as a silver paste and nano silver, in a body hole part.

(Third embodiment)
FIG. 8 is a perspective view showing an inductor element according to the third embodiment of the present invention. 9A and 9B are diagrams showing an inductor element according to a third embodiment of the present invention, where FIG. 9A is a side view, FIG. 9B is a cross-sectional view taken along the line DD ′ of FIG. c) is a bottom view.

  As shown in FIGS. 8 and 9, the inductor element 300 of the present invention is formed by binding a soft magnetic metal powder having a flat shape with a binder component, and a magnetic core 31 having holes and a conductor 32. And a terminal portion 33, an insulating nonmagnetic material 34, and an impregnating resin (not shown).

  The magnetic core 31 forms a groove in the thickness direction of the soft magnetic metal powder, and divides the magnetic core 31 into two. That is, the magnetic core 31 has two grooves at symmetrical positions with the conductor 32 as an axis, and the conductor 32 is sandwiched between the magnetic cores 31 divided into two. The two groove portions are filled with a nonmagnetic material 34 having an insulating property.

  Both end portions of the conductor 32 and the terminal portion 33 are electrically connected to each other. The terminal portion 33 is a side surface of the magnetic core 31 that is both end surfaces in the longitudinal direction of the conductor 32 and a side periphery that surrounds the side surface. Part of the part is fitted.

  The terminal portion 33 may be formed by plating a side surface of the magnetic core 31 and a part of a side peripheral portion surrounding the side surface, or by forming a metal powder such as silver paste or nano silver. Also good. Alternatively, the side surface of the magnetic core 31 and the side periphery of the side surface may be covered with a metal lid to form the terminal portion 33. In that case, the nonmagnetic material 34 may be formed and then covered with a lid, or after first covered with the lid, the nonmagnetic material 34 may be formed in the two groove portions.

  In the third embodiment and the fourth embodiment, the terminal portion is formed on the side surface of the magnetic core and a part of the side peripheral portion surrounding this side surface. You may form only in the side surface of the magnetic core which is the both end surfaces in a direction.

(Fourth embodiment)
10A and 10B are views showing an inductor element according to a fourth embodiment of the present invention, in which FIG. 10A is a perspective view and FIG. 10B is a cross-sectional view taken along line EE ′ of FIG. .

  As shown in FIG. 10, the inductor element 400 of the present invention includes two E-type magnetic cores 41, a conductor 42, and an impregnating resin (not shown).

  The E-type magnetic core 41 is formed by binding a soft magnetic metal powder having a flat shape with a binder component, and is provided with pores to form two grooves 43 and 44 in the thickness direction of the soft magnetic metal powder. doing. That is, the E-type magnetic core 41 includes a middle leg 45 surrounded by two grooves 43 and 44, a first outer leg 46, a second outer leg 47, a middle leg 45 and a first leg. A plate portion 48 for connecting the outer leg portion 46 and the second outer leg portion 47 to each other is provided.

  The magnetic core of the inductor element 400 of the present invention is such that the groove portions 43 and 44, the middle leg portion 45, the first outer leg portion 46, and the second outer leg portion 47 of the two E-type magnetic cores 41 face each other. And fixed with an adhesive (not shown). Further, the conductor 42 is wound around the middle leg portion 45.

  The two E-type magnetic cores 41 may be fixed with an adhesive or the like. For example, when the impregnating resin is formed, the two E-type magnetic cores 41 may be bonded with the same resin. In addition, when filling the gaps 43 and 44 formed by winding the conductor 42 with a nonmagnetic material having insulation properties, the same nonmagnetic material may be used for bonding.

  Further, in the present embodiment, when the conductor 42 is wound around the groove portions 43 and 44, a slight gap is generated, but the groove portions 43 and 44 may be filled with the conductor 42. .

  A gas atomized powder of Fe—Si—Al alloy was used as the soft magnetic metal powder, and the powder had an average particle diameter (D50) of 55 μm. The powder was flattened using a ball mill. Specifically, after forging for 8 hours, the powder was subjected to heat treatment at 700 ° C. for 3 hours in a nitrogen atmosphere, thereby obtaining a flat soft magnetic metal powder.

  Next, the obtained soft magnetic metal powder was mixed with a solvent, a thickener and a thermosetting binder component to prepare a slurry. Here, ethanol was used as a solvent, polyvinyl butyral was used as a thickener, and methylphenyl silicone resin was used as a thermosetting binder component.

  The slurry was applied on a PET (polyethylene terephthalate) film by a die slot method, and dried at 60 ° C. for 1 hour to remove the solvent, thereby preparing a magnetic layer. The obtained magnetic layer was cut using a die, and a predetermined number of magnetic layers were stacked and placed in a mold. The magnetic layer in the mold was subjected to pressure molding at a molding pressure of 200 MPa for 1 hour at a temperature of 150 ° C. The thickness after pressure molding was 3.2 mm. Thereafter, heat treatment was performed at 600 ° C. for 1 hour in a nitrogen atmosphere to obtain a laminate.

The obtained laminate had a density of 4.9 g / cm ³ and a volume resistivity of 10 KΩ · cm or more. From the density of the laminate, the volume filling rate of the soft magnetic metal powder in the laminate was determined. The volume filling rate of the soft magnetic metal powder was about 67%. The binder component for binding the soft magnetic metal powder was mainly composed of silicon oxide.

  Next, a plurality of groove portions were formed in the laminate. In the present embodiment, a method of forming a plurality of magnetic cores by cutting all the magnetic core grooves and then cutting in the stacking direction was used. At this time, a magnetic core having a portion where the conductor is disposed, that is, a groove portion having a width of 0.2 mm and a length of 0.5 mm as the conductor hole portion and a groove portion having a width of 0.1 mm as the portion where the conductor is not disposed is obtained. Grooves were formed as shown.

  After forming the groove part, the laminated body was cut so that the width was the same direction as the width of the groove part, the width was 1.2 mm, and the length was 2.5 mm.

  A copper plate having a thickness of 0.2 mm, a width of 0.5 mm, and a length of 4.6 mm was used as the conductor. After the conductor was inserted into the groove part, the gap portion of the groove part was filled with a resin made of acrylic resin. The acrylic resin was impregnated into the internal pores at least from the surface of the groove to form an impregnated resin. That is, the impregnating resin and the binder component are formed from different components.

  Next, both ends of the conductor protruding from the side surface of the magnetic core were bent along the magnetic core to form mounting terminals.

  In this embodiment, a conductor having the same thickness as the width of the groove is used. However, since the magnetic core according to the present invention has elasticity at the stage of inserting the conductor, the conductor having the same thickness as the width of the groove is used. The body can be easily inserted, and the conductor can be held. In addition, when the conductor was inserted, damage due to the pressing force could be suppressed.

  Furthermore, in the present invention, the surface strength of the magnetic core is increased by providing the impregnation resin at least from the surface of the groove, and delamination, cracks, and the like can be suppressed.

  As described above, according to the present invention, since the magnetic core has elasticity, the conductor can be easily inserted into the groove portion, and at least the surface of the groove portion is impregnated with the resin, thereby strengthening the bonding between the layers. Delamination and cracks can be suppressed. Therefore, it is possible to obtain an inductor element that is easy to manufacture and a manufacturing method thereof that suppresses cracks and the like of the magnetic core.

  As mentioned above, although the Example of this invention was described, this invention is not limited above, The change and correction of a structure are possible in the range which does not deviate from the summary of this invention. That is, it is a matter of course that various modifications and corrections that can be made by those skilled in the art are also included in the present invention.

1, 20, 21, 31 Magnetic core 2, 22, 32, 42 Conductor 3, 18, 43, 44 Groove 4 Soft magnetic metal powder 5 Binder component 6 Hole 7 Impregnation resin 8 Mounting terminal 9 Magnetic layers 10, 17 Lamination Body 11, 13, 14, 19 Cutting part 12 Laminate piece 15, 41 E-type magnetic core 23, 33 Terminal part 24, 34 Non-magnetic body 45 Middle leg part 46 First outer leg part 47 Second outer leg part 48 Plate part 100, 200, 300, 400 Inductor element

Claims (9)

A magnetic core having a groove,
A conductor inserted in the groove;
Comprising an impregnating resin having an insulating property impregnated from at least the groove,
The magnetic core is formed by binding a soft magnetic metal powder having a flat shape with a binder component,
The magnetic core has a hole inside,
At least one groove is formed along the thickness direction of the soft magnetic metal powder in the magnetic core,
The inductor element, wherein the binder component and the impregnating resin are different components.   The inductor element according to claim 1, wherein the impregnating resin is filled in at least a part of the holes.   3. The inductor element according to claim 1, wherein the groove portion is filled with a nonmagnetic material having an insulating property at least a part other than a portion where the conductor is disposed.   The inductor element according to claim 1, wherein both ends of the conductor are mounting terminals. Furthermore, it has a terminal part,
The terminal portions are electrically connected to both ends of the conductor,
4. The both ends of the magnetic core in the longitudinal direction of the conductor or a part of the side periphery connected to the both ends and the both ends are fitted. Inductor element. The magnetic core includes two groove portions, a middle leg portion, a first outer leg portion, a second outer leg portion, the middle leg portion, the first outer leg portion, and the second outer leg portion. The first E-type magnetic core and the second E-type magnetic core each having a plate portion connecting the leg portions are connected to the groove portion, the middle leg portion, the first outer leg portion, and the second outer leg portion. Are arranged to face each other,
The inductor element according to claim 1, wherein the conductor is formed by winding the middle leg portion.   The inductor element according to any one of claims 1 to 6, wherein a volume ratio of the holes is 10% by volume or more and 25% by volume or less of the volume of the magnetic core. Laminating a soft magnetic metal powder having a flat shape and a magnetic layer produced by a binder component, and binding the soft magnetic metal powder by the binder component to produce a laminate having pores;
Forming a plurality of magnetic cores by cutting grooves in the stacking direction of the stacked body and cutting in the stacking direction of the stacked body;
Inserting a conductor into the groove,
A method of manufacturing an inductor element comprising a step of impregnating a resin from at least the groove after inserting the conductor.   The method for manufacturing an inductor element according to claim 8, further comprising a step of filling the gap in the groove with an insulating nonmagnetic material after impregnating the resin.

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