Inductor and method for manufacturing inductor

Abstract

An inductor (100) is provided with: a dust core (10) having a first surface (11), a second surface (12) on the opposite side from the first surface (11), and at least one third surface (for example (13c)) connecting the first surface (11) and the second surface (12); and a coil element (20) made of a flat conductive wire. A coil element (20) is provided with: a wound body section (21) positioned inside a dust core (10); a lead-out portion (22) led out from an end portion of the winding body portion (21) toward the third surface (13c); and an electrode part (27) connected to the lead-out part (22) and protruding from the third surface (13c) to the outside of the dust core (10). The lead-out section (22) has a cutout (Nt) along the lead-out direction (Dr) of the lead-out section (22).

Description

Technical Field

[0001] The present disclosure relates to an inductor and a method for manufacturing the inductor. Background Art

[0002] An inductor, which is a passive element that stores electric energy as magnetic energy, is used, for example, in a DC-DC converter device for the purpose of stepping up or down a power supply voltage or smoothing a direct current. The inductor is mounted on a surface of a circuit board or the like, for example.

[0003] Patent document 1 discloses an inductor having a coil element made of a flat wire as a raw material and a powder core in which a part of the coil element is buried. The powder core is flat and is formed by stamping using a mold. The coil element has a winding body portion located inside the powder core and an electrode portion located outside the powder core.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2012-49435 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the inductor disclosed in Patent Document 1, when the powder core is stamped, the winding body disposed in the mold is sometimes tilted obliquely, and a portion of the flat wire connecting the winding body and the electrode portion is twisted. In this case, there is a problem that the powder core is damaged and the reliability of the inductor is reduced.

[0009] The present disclosure is made in view of the above-mentioned problems, and an object of the present disclosure is to improve the reliability of an inductor.

[0010] Means used to solve problems

[0011] An inductor according to a technical solution of the present disclosure comprises: a powder magnetic core having a first surface, a second surface opposite to the first surface, and at least one third surface connecting the first surface and the second surface; and a coil element made of a flat wire; the coil element comprises a winding body located inside the powder magnetic core, a lead-out portion extending from an end of the winding body toward the third surface, and an electrode portion connected to the lead-out portion and protruding from the third surface to the outside of the powder magnetic core; the lead-out portion comprises a notch along the lead-out direction of the lead-out portion.

[0012] A method for manufacturing an inductor according to a technical solution of the present disclosure includes: a coil element forming step of forming a coil element having a winding body portion wound with a flat conductive wire; and a powder core forming step of loading a portion of the coil element and a magnetic material into a mold and performing stamping to form a powder core including the coil element; in the powder core forming step, stamping is performed in a manner such that the winding body portion and a lead-out portion led out from an end of the winding body portion are arranged inside the powder core, and an electrode portion connected to the lead-out portion is arranged outside the powder core; in the coil element forming step, a notch is formed along the lead-out direction of the lead-out portion at the following position, which is the position of the lead-out portion in the powder core forming step.

[0013] Effects of the Invention

[0014] According to the present disclosure, the reliability of the inductor can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a perspective view showing an inductor of a comparative example.

[0016] Figure 2 The diagram shows cross sections of a coil element and a powder magnetic core during the manufacturing process of an inductor according to a comparative example.

[0017] Figure 3 It is a diagram showing an inductor according to an embodiment.

[0018] Figure 4 This is a diagram of the lead-out portion and the electrode portion according to the embodiment as viewed from the direction opposite to the lead-out direction.

[0019] Figure 5 1 is a flowchart showing a method for manufacturing an inductor according to an embodiment.

[0020] Figure 6 The diagrams show the coil element and the powder magnetic core in the process of manufacturing the inductor according to the embodiment.

[0021] Figure 7 The diagram shows cross sections of a coil element and a powder magnetic core during the manufacturing process of the inductor according to the embodiment.

[0022] Figure 8 It is a diagram showing an inductor according to Modification 1 of the embodiment.

[0023] Fig. 9 It is a diagram showing an inductor according to Modification 2 of the embodiment.

[0024] Fig.10 It is a diagram showing an inductor according to Modification 3 of the embodiment.

[0025] Fig.11 It is a diagram showing an inductor according to Modification 4 of the embodiment.

[0026] Fig.12 It is a diagram showing an inductor according to Modification 5 of the embodiment.

[0027] Fig.13 It is a perspective view showing an inductor according to Modification 6 of the embodiment. DETAILED DESCRIPTION

[0028] (Origin of this disclosure)

[0029] One side reference Figure 1 and Figure 2 The origin of the present disclosure will be described.

[0030] Figure 1 1 is a perspective view showing an inductor 500 according to a comparative example.

[0031] like Figure 1 As shown, the inductor 500 of the comparative example includes a coil element 120 made of a flat wire and a powder magnetic core 10 in which a part of the coil element 120 is buried.

[0032] The powder core 10 is a rectangular parallelepiped formed by press molding using a die and has a first surface 11, a second surface 12 facing away from the first surface 11, and four third surfaces 13a, 13b, 13c, and 13d connecting the first surface 11 and the second surface 12.

[0033] The coil element 120 has a winding body 21 and two lead portions 122 located inside the compressed magnetic core 10, and two electrode portions 27 located outside the compressed magnetic core 10. The winding body 21 is wound around a flat conductive wire having a rectangular cross-section with long and short sides, and has a shape in which the short sides are parallel to the winding axis AT and the surfaces including the long sides of adjacent flat conductive wires overlap. Of the two lead portions 122, one lead portion 122 is led out from one end 21a of the winding body 21 toward the third surface 13c of the compressed magnetic core 10, and the other lead portion 122 is led out from the other end 21b of the winding body 21 toward the third surface 13c of the compressed magnetic core 10. The two electrode portions 27 are respectively connected to the lead portions 122 on the third surface 13c, and extend from the third surface 13c to the outside in a horizontal direction (at Figure 1 protrudes in the Y-axis direction).

[0034] Figure 2 1 is a diagram showing a cross section of the coil element 120 and the powder magnetic core 10 during the manufacturing process of the inductor 500 of the comparative example. Figure 2 (a) shows the coil element 120 before stamping. Figure 2(b) shows the coil component 120 and the powder magnetic core 10 after stamping. Figure 2 This is a diagram of the coil element 120 and the powder magnetic core 10 as viewed from a direction perpendicular to the third surface 13a (Y-axis direction). Figure 2 In FIG. 1 , the electrode portion 27 , punches 91 and 92 , and molds 93 and 94 are indicated by hatching, and the hatching of the wound body portion 21 , the lead portion 22 , and the powder magnetic core 10 is omitted.

[0035] The winding body 21 is spiral. Figure 2 When the cross-sectional view shown in (a) is observed, the flat wire is stacked every time the flat wire is wound. Figure 2 When the thin wire (a) is formed by left winding, the winding body 21 has an asymmetric shape with the left side slanting upward and the right side slanting downward.

[0036] Therefore, in the mold 90, if a part of the coil element 120 (the winding body 21 and the lead-out portion 122) is arranged so that the winding axis AT of the winding body 21 is along the pressing direction of the stamping molding, and the mixture of the magnetic material powder and the binder is loaded to stamp the powder core 10, then Figure 2 As shown in (b), the winding body 21 and the lead-out portion 122 ( Figure 2 The electrode portion 27 (in the enlarged view of (b)) is slightly rotated and tilted to the left due to the pressure from the upper and lower punches 91 and 92. Figure 2 The lead portion 122 between the winding body portion 21 and the electrode portion 27 is twisted to the left because the lead portion 122 is clamped by the upper mold 93 and the lower mold 94 and fixed in the horizontal direction.

[0037] Therefore, during the press forming, the lead portion 122 is twisted as the press forming is pushed, and a shear force is generated between the molds 93 and 94 and the material (mixture of magnetic material powder and binder) of the moving powder core 10. In addition, there is a possibility that the lead portion 122 and the electrode portion 27 are partially ( Figure 2 In the enlarged view of FIG. 1 , shear damage occurs in the portion where the electrode portion 27 (the shaded portion) and the lead portion 122 (the portion surrounded by the dotted line) do not overlap. In addition, after the press molding, the lead portion 122 is released from the molds 93 and 94, and the residual stress remaining in the torsion direction of the lead portion 122 (the rebound force in an attempt to restore the torsion) may cause cracks in the powder core 10 around the lead portion 122 and damage. Thus, in the comparative example, there is a problem that the reliability of the inductor 500 is reduced due to the torsion of the lead portion 122.

[0038] The present disclosure has the following structure in order to improve the reliability of the inductor. Figure 1 The implementation modes will be described in more detail.

[0039] In addition, the embodiments described below all represent a specific example of the present disclosure. The numerical values, shapes, materials, components, configuration positions of components, connection forms, steps and the order of steps, etc. shown in the following embodiments are examples and are not intended to limit the present disclosure. In addition, among the components of the following embodiments, the components not described in the independent claims are described as arbitrary components.

[0040] In addition, in this specification, terms such as parallel that indicate the relationship between elements, terms such as rectangular that indicate the shape of elements, and numerical ranges do not express only strict meanings, but mean to include substantially the same range, such as differences of several percentage points.

[0041] In addition, each figure is a schematic diagram that appropriately emphasizes, omits, or adjusts the ratio in order to express the present disclosure, and is not necessarily a strict illustration, and there may be cases where the actual shape, positional relationship, and ratio are different. In each figure, there are cases where the same reference numerals are given to substantially the same structure and repeated descriptions are omitted or simplified.

[0042] In addition, the X-axis, Y-axis, and Z-axis, which are three mutually orthogonal directions, are shown in each figure, and these axes and axial directions along these axes are used for explanation as needed. In addition, each axis is added for explanation and does not limit the direction and posture of using the inductor.

[0043] In addition, in this specification, the terms "second surface" and "first surface" in the structure of the inductor do not refer to the second surface (the surface on the vertically upper side) and the first surface (the surface on the vertically lower side) in absolute spatial identification, but are used as terms defined by the relative positional relationship of the components of the inductor.

[0044] (Implementation Method)

[0045] [Inductor Structure]

[0046] The structure of the inductor according to the embodiment will be described. The inductor is a passive element that stores the electric energy flowing into a coil element as magnetic energy.

[0047] Figure 3 FIG. 1 is a diagram showing an inductor 100 according to an embodiment. Figure 3 (a) shows a three-dimensional view of the inductor 100. Figure 3 (b) shows an enlarged view of the area around the lead portion 22 of the inductor 100. Figure 3 (c) indicates that Figure 3 (b) Graph of the extracted gap Nt.

[0048] like Figure 3 As shown in (a) of FIG. 1 , the inductor 100 includes a coil element 20 made of a flat wire and a powder core 10 in which a portion of the coil element 20 is buried. Figure 3 In (a), a portion of the coil element 20 buried in the powder magnetic core 10 is indicated by a dotted line.

[0049] The inductor 100 has a general shape determined by the shape of the powder core 10, which is a rectangular magnetic molded body. In addition, the powder core 10 can be molded into any shape by mold molding. That is, the inductor 100 of any shape can be realized by the shape of the powder core 10 during molding. In the powder core 10 of the present embodiment, for example, the dimension in the X-axis direction is 40 mm, the dimension in the Y-axis direction is 40 mm, and the dimension in the Z-axis direction is 18 mm. In addition, the dimension of the powder core 10 in the X-axis direction is appropriately selected from the range of 17 mm to 70 mm, the dimension in the Y-axis direction is 17 mm to 70 mm, and the dimension in the Z-axis direction is 7 mm to 50 mm.

[0050] The pressed powder core 10 is the outer shell of the inductor 100, and covers a part of the coil element 20. The pressed powder core 10 includes a magnetic material, for example, a pressed powder core composed of a metal magnetic powder and a resin material. In addition, the pressed powder core 10 can be formed using only a magnetic material. Among the magnetic materials, ferrites can be used, and other magnetic materials can also be used. Among the metal magnetic powders, granular materials with a prescribed elemental composition such as Fe-Si-Al, Fe-Si, Fe-Si-Cr or Fe-Si-Cr-B are used. In addition, among the resin materials, a material such as a silicone resin is selected that can insulate the particles of the metal magnetic powder while bonding the particles of the metal magnetic powder to maintain a certain shape.

[0051] The powder core 10 is, for example, in the shape of a rectangular parallelepiped. The powder core 10 has a first surface 11, a second surface 12 on the opposite side of the first surface 11, and four third surfaces 13a, 13b, 13c, and 13d connecting the first surface 11 and the second surface 12. In the powder core 10 in the figure, the outer peripheral side surfaces are formed by the four third surfaces 13a to 13d.

[0052] The third surface 13a and the third surface 13b are arranged in the X-axis direction and face each other. The third surface 13c and the third surface 13d are arranged in the Y-axis direction and face each other. The first surface 11, the second surface 12 and the third surfaces 13a, 13b, 13c, and 13d are respectively substantially flat planes. The group of the first surface 11 and the second surface 12, the group of the third surface 13a and the third surface 13b, and the group of the third surface 13c and the third surface 13d are respectively groups of surfaces in a parallel positional relationship. The first surface 11 and the second surface 12 and the third surfaces 13a, 13b, 13c, and 13d extend in intersecting directions, specifically in orthogonal directions. In addition, the third surface 13a and the third surface 13b and the third surface 13c and the third surface 13d extend in intersecting directions, specifically in orthogonal directions.

[0053] The coil component 20 includes a winding body portion 21 and a plurality of lead portions 22 located inside the powder magnetic core 10 , and a plurality of electrode portions 27 located outside the powder magnetic core 10 .

[0054] The coil element 20 is formed of, for example, a flat conductive wire that is a flat conductive wire. The conductive wire is, for example, composed of a metal wire and an insulating film covering the metal wire, and the metal wire is composed of a metal material selected from metals such as aluminum, copper, silver, and gold, alloys containing one or more of these metals, and materials formed of metals or alloys and other substances. Specifically, the conductive wire is, for example, a copper wire covered with an insulating film. The winding body portion 21, the lead portion 22, and the electrode portion 27 are, for example, names given to the respective parts formed by processing a component composed of the same material.

[0055] The coil component 20 of the present embodiment includes one winding body 21 , a pair of lead portions 22 connected to both ends of the winding body 21 , and a pair of electrode portions 27 connected to the pair of lead portions 22 in a one-to-one correspondence.

[0056] The winding body 21 is a portion covered by the powder core 10. The winding body 21 is composed of a wound conductive wire and functions as a coil. The winding body 21 is embedded in the powder core 10 in such a manner that the winding axis AT of the winding body 21 intersects the first surface 11 and the second surface 12. When viewed from a direction perpendicular to the third surface 13c, one end 21a of the two ends of the winding body 21 is arranged on the left outer side of the winding axis AT, that is, on the negative side of the X-axis, and the other end 21b is arranged on the right outer side of the winding axis AT, that is, on the positive side of the X-axis.

[0057] The cross-section of the wire used to form the wound body 21 is a rectangular shape, for example, the long side is 6.0 mm and the short side is 3.0 mm. The wound body 21 is wound in a manner such that the short side is parallel to the winding axis AT and the surfaces of the adjacent flat wires including the long sides overlap. There is no particular limitation on the number of turns of the wound body 21, for example, 1.5 turns to 10 turns, etc., and it is appropriately selected to match the performance required for the inductor 100 and the size of the pressed powder core 10. In addition, the actual wound body 21 is formed by winding around the winding axis AT as the center, and the thickness on the inner side becomes thicker and the thickness on the outer side becomes thinner. Therefore, the cross-section of the wire of the wound body 21 has a trapezoidal shape with the inner side side as the lower base and the outer side side as the upper base.

[0058] The pair of electrode portions 27 are portions that are connected to a wiring pattern or the like on a circuit board when the inductor 100 is mounted on the circuit board. The pair of electrode portions 27 is composed of one electrode portion 27 and the other electrode portion 27. The insulating film on the surface of the electrode portion 27 is removed. Solder plating may be formed on the portion where the insulating film is removed.

[0059] Each electrode portion 27 extends outward from the third surface 13c of the powder magnetic core 10 in a horizontal direction (at Figure 1 That is, each electrode portion 27 protrudes from the same one third surface 13c among the plurality of third surfaces 13a to 13d.

[0060] The electrode portion 27 is formed by a portion of the above-mentioned wire, and has a rectangular cross section. The electrode portion 27 has two long sides 28a, 28b and two short sides 29a, 29b connecting the two long sides 28a, 28b. The two long sides 28a, 28b are parallel to the first surface 11 and the second surface 12, and the two short sides 29a, 29b are parallel to the third surface 13a, 13b. The electrode portion 27 is connected to the lead portion 22 at the third surface 13c of the powder core 10.

[0061] The pair of lead portions 22 are portions that connect the wound body 21 to the electrode portion 27. The pair of lead portions 22 is composed of one lead portion 22 disposed between one end 21a of the wound body 21 and one electrode portion 27, and another lead portion 22 disposed between the other end 21b of the wound body 21 and the other electrode portion 27. Each lead portion 22 is linearly led from the end of the wound body 21 toward the third surface 13c of the powder magnetic core 10. That is, the lead portion 22 is led toward the same one third surface 13c among the four third surfaces 13a to 13d.

[0062] The direction of leading portion 22 from wound body 21 toward third surface 13c of powder core 10 is hereinafter referred to as “leading direction Dr.” Leading direction Dr is parallel to first surface 11, second surface 12, and third surfaces 13a and 13b, and perpendicular to third surfaces 13c and 13d. Figure 3 The lead-out direction Dr in is the direction opposite to the arrow in the Y-axis direction.

[0063] When viewed from the opposite direction of the lead direction Dr (the Y-axis direction), one lead portion 22 and one electrode portion 27 are arranged on the left outer side of the winding axis AT, that is, on the negative side of the X-axis, and are arranged on the left outer side of the winding axis AT and on the negative side of the X-axis from the center 21c of the winding body 21 (see Figure 4 ) is on the second surface 12 side, i.e., the positive side of the Z axis. In addition, the other lead portion 22 and the other electrode portion 27 are arranged on the right outer side of the winding axis AT, i.e., the positive side of the X axis, and are arranged on the first surface 11 side, i.e., the negative side of the Z axis, from the height of the center 21c of the winding body 21. In addition, the center 21c of the winding body 21 is a point on the winding axis AT, and is the midpoint of the height positions of the two ends of the winding body 21 in the axial direction of the winding axis AT.

[0064] In the following description, the negative half of the inductor 100 on the X-axis is mainly described. The positive half of the inductor 100 on the X-axis has the same structure as the negative half of the inductor 100 on the X-axis, and the same description applies.

[0065] In this embodiment, in order to suppress the reliability of the inductor 100 from being reduced due to the twisting of the lead portion 22 during stamping, a notch Nt is provided in the lead portion 22. Providing the notch Nt in the lead portion 22 makes it easy to twist the lead portion 22. As a result, the force in the twisting direction generated in the lead portion 22 due to the inclination of the wound body portion 21 relative to the electrode portion 27 during stamping can be reduced.

[0066] The notch Nt is a groove provided along the lead-out direction Dr. The notch Nt is a groove, and the cross section perpendicular to the lead-out direction Dr is V-shaped. For example, the notch Nt is formed by cutting the lead-out portion 22 with a cutter having a V-shaped cross section. Since the cutter compresses and expands the conductor material in the direction along the cross section to form the notch Nt, the cross-sectional area of ​​the lead-out portion 22 that becomes the circuit is the same before and after the notch Nt is formed. In addition, at the portion where the notch Nt is formed, the insulating film of the conductor is removed by the cutter, and the conductor raw material is exposed. An insulating resin may also be applied to the exposed portion of the conductor raw material.

[0067] The notch Nt is provided between the midpoint 22m of the lead-out portion 22 in the lead-out direction Dr and the third surface 13c. The midpoint 22m of the lead-out portion 22 in the lead-out direction Dr is the position of the center of the line connecting one end of the lead-out portion 22 connected to the winding body portion 21 and the other end of the lead-out portion 22 in contact with the third surface 13c. The notch Nt of the present embodiment contacts the third surface 13c and does not contact the midpoint 22m of the lead-out portion 22. That is, the notch Nt is provided at a position that is more biased toward the third surface 13c side than the midpoint 22m of the lead-out portion 22. During stamping, a force in a torsional direction acts on the lead-out portion 22 between the winding body portion 21 and the electrode portion 27, but most of the twisted shape is the area of ​​the lead-out portion 22 where the notch Nt is provided.

[0068] like Figure 3 As shown in (b), the cross section of the lead portion 22 perpendicular to the lead direction Dr is a rectangular shape. In addition, since the lead portion 22 has a twisted shape, there are also parts whose cross section is not a rectangle strictly speaking, and the following description is made as a shape close to a rectangle.

[0069] Figure 4 This is a diagram of the lead portion 22 and the electrode portion 27 viewed from the opposite direction of the lead direction Dr. Figure 4 The enlarged view of FIG. 2 shows a cross section of the electrode portion 27 and a cross section near one end of the lead portion 22 connected to one end 21a of the wound body portion 21. Only the electrode portion 27 is shaded.

[0070] like Figure 4 As shown, the lead-out portion 22 has two long sides 23a, 23b and two short sides 24a, 24b connecting the two long sides 23a, 23b. When viewed from the opposite direction of the lead-out direction Dr, the outer long side 23a of the two long sides is located closer to the second surface 12 than the inner long side 23b and farther from the center 21c of the winding body 21. In addition, the outer short side 24a of the two short sides is located closer to the third surface 13b than the inner short side 24b and farther from the winding axis AT and the center 21c of the winding body 21.

[0071] Since the lead portion 22 is twisted in the region where the notch Nt is provided, the long side 23a of the lead portion 22 and the long side 28a of the electrode portion 27 intersect each other when viewed from the opposite direction of the lead direction Dr. The angle at which the long side 23a and the long side 28a intersect each other is, for example, 5° or more and 15° or less. Similarly, the short side 24a of the lead portion 22 and the short side 29a of the electrode portion 27 intersect each other. The angle at which the short side 24a and the short side 29a intersect each other is, for example, 5° or more and 15° or less. The angle of intersection is an acute angle among an acute angle and an obtuse angle formed by the intersection.

[0072] The notch Nt is provided at the center of the outer long side 23a of the two long sides. If the exposed portion of the wire material is close to the wound body 21 due to the formation of the notch Nt, the reliability of the inductor 100 will be affected. Therefore, the notch Nt is preferably provided at the long side 23a farther from the center 21c of the wound body 21.

[0073] like Figure 3 As shown in (c), the length L of the notch along the lead-out direction Dr is not less than 0.5 times and not more than 1.5 times the length of the long side 28a. This is because if the length L of the notch is too short, the lead-out portion 22 is not easily twisted during stamping, and if the length L is too long, the notch Nt after the insulating film is removed is close to the center 21c of the winding body 21, which affects the reliability of the inductor 100.

[0074] In addition, the length L of the notch along the lead-out direction Dr is longer than the width w of the notch. In addition, the central portion Ntc of the notch in the lead-out direction Dr of the notch Nt is narrower than the end portion Nte of the notch. That is, the width of the notch has a relationship of (width w2 of the end portion Nte)>(width w1 of the central portion Ntc). In addition, when the notch Nt is a V-shaped groove, the width w is the maximum width on the long side 23a.

[0075] The depth dp of the notch is 1.0 to 3.0 times the width w of the notch. In addition, the depth dp of the notch may be 0.2 to 0.6 times the thickness of the wire, i.e., the short side dimension. In addition, when the notch Nt is a V-shaped groove, the depth dp is the maximum depth when the long side 23a is used as a reference.

[0076] Thus, in the present embodiment, a notch Nt is provided in the lead-out portion 22 of the coil element 20, and the lead-out portion 22 has a structure that is easily twisted. According to this structure, the lead-out portion 22 is easily twisted. For example, since the winding body portion 21 is tilted relative to the electrode portion 27 during stamping, the force in the twisting direction generated in the lead-out portion 22 can be reduced. Therefore, it is possible to suppress shear damage to the wire at the portion connecting the electrode portion 27 to the lead-out portion 22. As a result, it is possible to suppress the deterioration of the temperature rise during power-on caused by the reduction in the cross-sectional area of ​​the wire due to shear damage and the reduction in the strength of the electrode portion. In addition, for example, after stamping, the residual stress (the rebound force that the twist attempts to recover) remaining in the twisting direction of the lead-out portion 22 can be reduced, and the powder core 10 around the lead-out portion 22 can be suppressed from cracking and being damaged. Thus, it is possible to suppress the reliability of the inductor 100 from being reduced.

[0077] [Inductor Manufacturing Method]

[0078] Next, use the appropriate Figure 5 to Figure 7 A method for manufacturing the above-mentioned inductor 100 will be described.

[0079] Figure 5 1 is a flowchart showing a method for manufacturing the inductor 100 according to the embodiment. Figure 6 The diagrams show the coil component 20 and the powder magnetic core 10 in the process of manufacturing the inductor 100 according to the embodiment. Figure 7 The diagram shows cross sections of the coil component 20 and the powder magnetic core 10 during the manufacturing process of the inductor 100 according to the embodiment.

[0080] like Figure 5 As shown, the method for manufacturing the inductor 100 includes a coil element forming step S101 and a powder magnetic core forming step S102 .

[0081] In the coil element forming step S101, Figure 6 As shown in (a), the winding body 21 is formed by winding the flat wire. Specifically, the short side of the flat wire is set as the winding axis AT side, and the winding body 21 is formed by winding 2.5 turns around the winding axis AT in a left direction. The winding body 21 has a spiral shape. Figure 7 Observing the cross-sectional view shown in (a), it becomes a left-right asymmetrical shape with the left side tilted upward and the right side tilted downward. In addition, the actual winding body 21 is formed by winding around the winding axis AT, so that the thickness of the inner circumference becomes thicker and the thickness of the outer circumference becomes thinner. Therefore, the cross section of the wire of the winding body 21 is deformed into a trapezoidal shape with the inner circumference side as the lower base and the outer circumference side as the upper base.

[0082] Furthermore, in the coil element forming step S101, the following regions are formed: Figure 6 The notch Nt shown in (b) is a region that becomes the lead-out portion 22 in the subsequent powder core forming step S102. The notch Nt is a depression, and is formed, for example, by pressing a tool having a V-shaped cross section onto the lead-out portion 22. By this pressing process, a notch Nt is formed in the region that becomes the lead-out portion 22 along the direction in which the flat wire extends. The notch Nt is provided in each of the pair of lead-out portions 22. The notch Nt may be provided after the winding body 21 is formed, or may be provided before the winding body 21 is formed.

[0083] In the powder magnetic core forming step S102, Figure 6 (c) and Figure 7As shown in FIG. (b), the powder compact magnetic core 10 is stamped together with the coil element 20. In this process, the wound body portion 21 and the lead-out portion 22, which are part of the coil element 20, are placed in the mold 90 and covered with a mixture containing magnetic material powder and a binder. The electrode portion 27, which is another part of the coil element 20, is not covered with the magnetic material, and the powder compact magnetic core 10 is formed by stamping. Specifically, stamping is performed using a mold 90 having an upper die 93 and a lower die 94 that form the third surfaces 13a to 13d of the powder compact magnetic core 10, a punch 91 that forms the first surface 11 of the powder compact magnetic core 10, and a punch 92 that forms the second surface 12. A part of the coil element 20 covered by the powder compact magnetic core 10 becomes the wound body portion 21 and the lead-out portion 22, and another part of the coil element 20 not covered by the powder compact magnetic core 10 becomes the electrode portion 27. The pressing force during stamping is, for example, 5 ton / cm 2 , and the heat curing temperature is, for example, 185°C.

[0084] First, the wound body portion 21 is arranged in the mold 90 such that the winding axis AT of the wound body portion 21 is along the pressing direction of the stamping. However, since the wound body portion 21 has an asymmetrical shape on the left and right, it is slightly rotated and inclined to the left under the pressure applied by the punches 91 and 92 during stamping. In addition, the flat wire after being deformed into a trapezoidal shape of the wound body portion 21 is deformed in such a way that the gaps on the outer peripheral sides of adjacent flat wires are narrowed. On the other hand, during stamping, since the electrode portion 27 is clamped by the upper die 93 and the lower die 94 and fixed in the horizontal direction, the lead-out portion 22 between the wound body portion 21 and the electrode portion 27 becomes a shape twisted to the left. In the present embodiment, a notch Nt is formed in the lead-out portion 22 in advance, and the lead-out portion 22 has a structure that is easily twisted. Therefore, the force in the twisting direction generated in the lead-out portion 22 when the wound body portion 21 is inclined with respect to the electrode portion 27 during stamping can be reduced.

[0085] In addition, since the lead-out portion 22 is twisted to the left, the central portion Ntc of the notch in the lead-out direction Dr is as shown in the enlarged views of FIGS. (b) and (c) of Figure 6 , the width w1 after stamping becomes narrower than the width w11 before stamping (w1 < w11). The bottom of the notch Nt is linear along the extending direction of the flat wire before stamping, but becomes curved after stamping.

[0086] After stamping, the electrode portion 27 not covered by the powder compact magnetic core 10 protrudes outward perpendicularly to the third surface 13c of the powder compact magnetic core 10. For example, a laser beam is irradiated on the electrode portion 27 to remove the insulating film. Solder plating or the like is performed as needed in the area after the insulating film is removed. Through these processes, the inductor 100 is manufactured.

[0087] [Modification 1 of the embodiment]

[0088] An inductor 100A according to a first modification of the embodiment will be described. In the first modification, an example in which the depth of the notch varies depending on the location and is not constant will be described.

[0089] Figure 8 FIG. 1 is a diagram showing an inductor 100A according to a first modification of the embodiment. Figure 8 (a) shows a three-dimensional view of the inductor 100A. Figure 8 (b) indicates that Figure 8 (a) is a diagram of the extracted gap Nt. Figure 8 (b) shows a notch Nt before a torsional force is applied to the lead portion 22 as a part of the wire before press forming.

[0090] The inductor 100A of the first modification includes a coil element 20 having a winding body portion 21 , a lead portion 22 , and an electrode portion 27 , and a powder core 10 in which the lead portion 22 and the electrode portion 27 , which are parts of the coil element 20 , are embedded. The lead portion 22 is provided with a notch Nt.

[0091] The notch Nt of the modification example 1 is also a groove provided along the lead-out direction Dr. The notch Nt is a groove, and the cross section perpendicular to the lead-out direction Dr is V-shaped. Figure 8 As shown in (b), the center Ntc of the notch in the leading direction Dr of the notch Nt of Modification 1 is deeper than the end Nte of the notch. That is, the depth of the notch has the relationship of (depth dp2 at the end Nte) < (depth dp1 at the center Ntc).

[0092] The notch Nt is formed by cutting the lead-out portion 22 using a cutter having a V-shaped cross section. The cutter head, which is the front end of the cutter, is curved along the length direction of the cutter, which is a direction perpendicular to the cross section. When the cutter is observed from the width direction perpendicular to the length direction just before the cut-out portion 22 is cut, the cutter head at the center protrudes toward the lower side, i.e., the lead-out portion 22 side, more than the cutter heads at the two end portions. The cutter head when observed from the width direction may be an elliptical curve or an arc-shaped curve. By setting the cutter head to be curved, the notch Nt can be easily formed.

[0093] The inductor 100A of the first modification also has a notch Nt provided along the lead direction Dr in the lead portion 22 of the coil element 20 . This can prevent the reliability of the inductor 100A from being reduced due to the twisting of the lead portion 22 .

[0094] [Variation 2 of the embodiment]

[0095] An inductor 100B according to a second modification of the embodiment will be described. In the second modification, an example in which the notch Nt is a through hole will be described.

[0096] Fig. 9 FIG. 1 is a diagram showing an inductor 100B according to a second modification of the embodiment. Fig. 9 (a) shows a three-dimensional view of the inductor 100B. Fig. 9 (b) of FIG. 1 shows an enlarged view of the area around the lead portion 22 of the inductor 100B. Fig. 9 (c) indicates that Fig. 9 (b) Graph of the extracted gap Nt.

[0097] The inductor 100B of the second modification includes a coil element 20 having a winding body portion 21, a lead portion 22, and an electrode portion 27, and a powder core 10 in which the lead portion 22 and the electrode portion 27, which are parts of the coil element 20, are embedded. The lead portion 22 is provided with a notch Nt.

[0098] The notch Nt of variant 2 is a through hole provided along the lead-out direction Dr. The hole shape of the notch Nt is, for example, a quadrilateral or a long hole. The length L of the notch along the lead-out direction Dr is not less than 0.5 times and not more than 1.5 times the length of the long side 28a. In addition, the length L of the notch along the lead-out direction Dr is longer than the width w of the notch. In addition, the central portion Ntc of the notch in the lead-out direction Dr of the notch Nt is narrower than the width of the end portion Nte of the notch. That is, the width of the notch has the relationship of (width w2 at the end portion Nte)>(width w1 at the central portion Ntc). The notch Nt is formed by laser processing or blanking processing using a punch.

[0099] The inductor 100B of the second modification also has a notch Nt provided along the lead direction Dr in the lead portion 22 of the coil element 20 . This can suppress a decrease in the reliability of the inductor 100B due to twisting of the lead portion 22 .

[0100] [Variation 3 of the embodiment]

[0101] An inductor 100C according to a third modification of the embodiment will be described. In the third modification, an example in which the notches Nt are provided on both long sides and both short sides of the lead portion 22 will be described.

[0102] Fig.10 FIG. 1 is a diagram showing an inductor 100C according to a third modification of the embodiment. Fig.10 (a) shows a three-dimensional view of the inductor 100C. Fig.10 (b) indicates that Fig.10 (a) is a diagram of the extracted gap Nt. Fig.10(b) shows a notch Nt before a torsional force is applied to the lead portion 22 as a part of the wire before press forming.

[0103] The inductor 100C of the third modification includes a coil element 20 having a winding body portion 21, a lead portion 22, and an electrode portion 27, and a powder core 10 in which the lead portion 22 and the electrode portion 27, which are parts of the coil element 20, are embedded. The lead portion 22 is provided with a notch Nt.

[0104] The notch Nt of Modification 3 is also a groove provided along the lead-out direction Dr. The notch Nt is a groove, and the cross section perpendicular to the lead-out direction Dr is V-shaped. The depth dp of each notch is not less than 0.5 times and not more than 1.5 times the width w of the notch. The depth dp of each notch may also be not less than 0.1 times and not more than 0.3 times the thickness of the wire, i.e., the short side dimension.

[0105] In variant example 3, four notches Nt are provided in the lead-out portion 22. Specifically, the notches Nt are provided in the center of the long side 23a, the center of the long side 23b, the center of the short side 24a, and the center of the short side 24b, respectively. The notches Nt of the long side 23a and the notches Nt of the long side 23b are provided so that the front ends of the two V-shaped shapes face each other in a direction parallel to the short side, and the distance connecting the front ends of the two V-shaped shapes is shorter than that of the long side. In addition, the notches Nt of the short side 24a and the notches Nt of the short side 24b are provided so that the front ends of the two V-shaped shapes face each other in a direction parallel to the long side, and the distance connecting the front ends of the two V-shaped shapes is shorter than that of the short side. The lead-out portion 22 of variant example 3 has a cross-sectional shape that is easier to twist than the embodiment, and can further reduce the force in the twisting direction generated in the lead-out portion 22 during stamping.

[0106] The inductor 100C of the third modification also has a notch Nt provided along the lead direction Dr in the lead portion 22 of the coil element 20 . This can prevent the reliability of the inductor 100C from being reduced due to the twisting of the lead portion 22 .

[0107] [Variation 4 of the embodiment]

[0108] An inductor 100D according to a fourth modification of the embodiment will be described. In the fourth modification, the notch Nt is provided in the long side 23a of the two long sides farther from the center 21c of the winding body 21 and in the short side 24a of the two short sides farther from the winding axis AT.

[0109] Fig.11 FIG. 1 is a diagram showing an inductor 100D according to a fourth modification of the embodiment. Fig.11 (a) shows a three-dimensional view of the inductor 100D. Fig.11 (b) indicates that Fig.11 (a) is a diagram of the extracted gap Nt. Fig.11 (b) shows a notch Nt before a torsional force is applied to the lead portion 22 as a part of the wire before press forming.

[0110] The inductor 100D of the fourth modification includes a coil element 20 having a winding body portion 21, a lead portion 22, and an electrode portion 27, and a powder core 10 in which the lead portion 22 and the electrode portion 27, which are parts of the coil element 20, are embedded. The lead portion 22 is provided with a notch Nt.

[0111] The notch Nt of Modification 4 is also a groove provided along the lead-out direction Dr. The notch Nt is a concave groove, and a cross section perpendicular to the lead-out direction Dr is V-shaped.

[0112] In Modification 4, two notches Nt are provided in the lead portion 22. Specifically, the notch Nt is provided in the long side 23a located outside the center 21c of the winding body 21, of the two long sides. In addition, the notch Nt is provided in the short side 24a located outside the winding axis AT (or the center 21c) of the winding body 21, of the two short sides. For example, the insulating film is removed from the portion where the notch Nt is formed, and the wire material is exposed. However, by providing the notch Nt in the long side 23a or the short side 24a located outside the center 21c or the winding axis AT of the winding body 21, it is possible to suppress the influence on the reliability of the inductor 100D.

[0113] The inductor 100D according to the fourth modification also has a notch Nt provided along the lead direction Dr in the lead portion 22 of the coil element 20 . This can suppress a decrease in the reliability of the inductor 100D due to twisting of the lead portion 22 .

[0114] [Variation 5 of the embodiment]

[0115] An inductor 100E according to a fifth modification of the embodiment will be described. In the fifth modification, an example in which the notch Nt is provided at a position close to the third surface 13c instead of being in contact with the third surface 13c will be described.

[0116] Fig.12 FIG. 1 is a diagram showing an inductor 100E according to a fifth modification of the embodiment. Fig.12 (a) shows a three-dimensional view of the inductor 100E. Fig.12 (b) is an enlarged view of the area around the lead portion 22 of the inductor 100E.

[0117] The inductor 100E of the fifth modification includes a coil element 20 having a winding body portion 21, a lead portion 22, and an electrode portion 27, and a powder core 10 in which the lead portion 22 and the electrode portion 27, which are parts of the coil element 20, are embedded. The lead portion 22 is provided with a notch Nt.

[0118] The notch Nt of Modification 5 is also a groove provided along the lead-out direction Dr. The notch Nt is a concave groove, and a cross section perpendicular to the lead-out direction Dr is V-shaped.

[0119] The notch Nt of modification example 5 is provided between the midpoint 22m of the lead-out portion 22 in the lead-out direction Dr and the third surface 13c. The notch Nt of modification example 5 is provided at a position closer to the third surface 13c than the midpoint 22m of the lead-out portion 22, but does not contact the third surface 13c. That is, the notch Nt is provided at a position close to the third surface 13c. The distance between the end Nte of the notch closest to the third surface 13c and the third surface 13c is, for example, not less than 0.1 mm and not more than 0.5 mm. For example, if the notch Nt is provided at an outer side than the third surface 13c, there is a possibility that magnetic material powder leaks out of the notch Nt during stamping. However, by reliably providing the notch Nt between the midpoint 22m of the lead-out portion 22 and the third surface 13c, it is possible to suppress the magnetic material powder from leaking out of the mold 90.

[0120] In the inductor 100E of the fifth modification, the lead portion 22 of the coil element 20 is also provided with a notch Nt along the lead direction Dr. This can prevent the reliability of the inductor 100E from being reduced due to the twisting of the lead portion 22 .

[0121] [Variation 6 of the embodiment]

[0122] An inductor 100F according to a sixth modification of the embodiment will be described. In the sixth modification, an example in which one electrode portion 27 is provided at the same height as the other electrode portion 27 will be described.

[0123] Fig.13 1 is a perspective view showing an inductor 100F according to Modification 6.

[0124] The inductor 100F of the sixth modification includes a coil element 20 having a winding body portion 21, a lead portion 22, and an electrode portion 27, and a powder core 10 in which the lead portion 22 and the electrode portion 27, which are parts of the coil element 20, are embedded. The lead portion 22 is provided with a notch Nt.

[0125] like Fig.13 As shown, a pair of lead portions 22 are connected to the ends of the winding body 21 and are led out toward the third surface 13c of the powder magnetic core 10. One lead portion 22 is led out from one end 21a of the winding body 21 toward the third surface 13c, and is bent toward the first surface 11 along the third surface 13c before reaching the third surface 13c, and is further bent along the first surface 11 before reaching the first surface 11, and is led out toward the third surface 13c.

[0126] One electrode portion 27 is connected to one lead portion 22 on the third surface 13c and protrudes outward from the third surface 13c. One electrode portion 27 is provided at the same height as the other electrode portion 27. The other lead portion 22 and the other electrode portion 27 are the same as those in the embodiment.

[0127] The notch Nt of Modification 6 is also a groove provided along the lead-out direction Dr. The notch Nt is a groove, and the cross section perpendicular to the lead-out direction Dr is V-shaped. The notch Nt of Modification 6 is provided in a region of a lead-out portion 22 extending along the lead-out direction Dr and in contact with the third surface 13c, that is, provided in a region where the lead-out portion 22 is bent along the first surface 11 and led toward the third surface 13c. The notch Nt is provided between the midpoint 22m of a lead-out portion 22 in the lead-out direction Dr and the third surface 13c when viewed from a direction perpendicular to the second surface 12.

[0128] In addition, the notch Nt of Modification 6 is provided on the long side facing the second surface 12 among the two long sides of one lead portion 22 , but the present invention is not limited thereto and may be provided on the long side facing the first surface 11 .

[0129] In the inductor 100F of the sixth modification, the lead portion 22 of the coil element 20 is also provided with a notch Nt along the lead direction Dr. This can prevent the reliability of the inductor 100F from being reduced due to the twisting of the lead portion 22 .

[0130] (Summarize)

[0131] As described above, the inductor 100 according to the present embodiment includes: a powder core 10 including a first surface 11, a second surface 12 on the opposite side of the first surface 11, and at least one third surface (e.g., 13c) connecting the first surface 11 and the second surface 12; and a coil element 20 made of a flat wire. The coil element 20 includes: a winding body 21 located inside the powder core 10; a lead portion 22 extending from an end of the winding body 21 toward the third surface 13c; and an electrode portion 27 connected to the lead portion 22 and protruding from the third surface 13c to the outside of the powder core 10. The lead portion 22 includes a notch Nt along the lead direction Dr of the lead portion 22.

[0132] In the inductor 100, a notch Nt is provided in the lead portion 22 of the coil element 20, and the lead portion 22 has a structure that is easy to twist. According to this structure, for example, it is possible to reduce the force in the twisting direction generated in the lead portion 22 due to the inclination of the winding body portion 21 relative to the electrode portion 27 during stamping. Therefore, it is possible to suppress shear damage to the wire at the portion connecting the electrode portion 27 and the lead portion 22. In addition, it is possible to reduce the residual stress in the twisting direction remaining in the lead portion 22, and it is possible to suppress damage to the powder core 10 around the lead portion 22 after stamping. As a result, it is possible to suppress a decrease in the reliability of the inductor 100.

[0133] In addition, the notch Nt may be a groove provided along the lead-out direction Dr.

[0134] Thus, the lead portion 22 has a structure that is easy to twist due to the groove, and for example, the force in the twisting direction generated in the lead portion 22 during press forming can be reduced. Therefore, it is possible to suppress shear damage to the wire at the portion connecting the electrode portion 27 and the lead portion 22. In addition, the residual stress in the twisting direction remaining in the lead portion 22 can be reduced, and the powder core 10 around the lead portion 22 after press forming can be suppressed from being damaged. As a result, it is possible to suppress a decrease in the reliability of the inductor 100.

[0135] Furthermore, the cross section of the groove perpendicular to the extraction direction Dr may be V-shaped.

[0136] Thus, the lead portion 22 has a structure that is easy to twist due to the groove, and for example, the force in the twisting direction generated in the lead portion 22 during press forming can be reduced. Therefore, it is possible to suppress shear damage to the wire at the portion connecting the electrode portion 27 and the lead portion 22. In addition, the residual stress in the twisting direction remaining in the lead portion 22 can be reduced, and the powder core 10 around the lead portion 22 after press forming can be suppressed from being damaged. As a result, it is possible to suppress a decrease in the reliability of the inductor 100.

[0137] In addition, the notch Nt may be a through hole provided along the lead-out direction Dr.

[0138] Thus, the lead portion 22 has a structure that is easy to twist due to the through hole, and for example, the force in the twisting direction generated in the lead portion 22 during press forming can be reduced. Therefore, it is possible to suppress shear damage of the wire at the portion connecting the electrode portion 27 and the lead portion 22. In addition, the residual stress in the twisting direction remaining in the lead portion 22 can be reduced, and the powder core 10 around the lead portion 22 after press forming can be suppressed from being damaged. As a result, it is possible to suppress a decrease in the reliability of the inductor 100B.

[0139] In addition, the notch Nt may be in contact with the third surface 13c.

[0140] Thus, the lead portion 22 of the third surface 13c has a structure that is easy to twist, and for example, the force in the twisting direction generated between the electrode portion 27 and the lead portion 22 during press forming can be reduced. Therefore, it is possible to suppress shear damage of the wire at the portion connecting the lead portion 22 and the electrode portion 27. As a result, it is possible to suppress a decrease in the reliability of the inductor 100.

[0141] The lead portion 22 has a rectangular cross section perpendicular to the lead direction Dr and has long sides 23a and 23b and short sides 24a and 24b. The notch Nt may be provided at the center of the long side 23a (or 23b).

[0142] Thus, the lead portion 22 has a structure that is easy to twist due to bilateral symmetry, and for example, the force in the twisting direction generated in the lead portion 22 during press forming can be reduced. Therefore, it is possible to suppress shear damage to the wire at the portion connecting the electrode portion 27 and the lead portion 22. In addition, the residual stress in the twisting direction remaining in the lead portion 22 can be reduced, and the powder core 10 around the lead portion 22 after press forming can be suppressed from being damaged. As a result, it is possible to suppress a decrease in the reliability of the inductor 100.

[0143] Furthermore, when viewed from the lead direction Dr, the lead portion 22 may have a rectangular cross section, the electrode portion 27 may have a rectangular cross section, and the long sides 23 a of the lead portion 22 and the long sides 28 a of the electrode portion 27 may intersect with each other.

[0144] Thus, even when the long side 23a of the lead portion 22 and the long side 28a of the electrode portion 27 are twisted so as to intersect, the force in the twisting direction generated in the lead portion 22 during the press forming can be absorbed by providing the notch Nt in the lead portion 22. Therefore, it is possible to suppress shear damage of the wire at the portion connecting the electrode portion 27 and the lead portion 22. In addition, it is possible to reduce the residual stress in the twisting direction remaining in the lead portion 22, and it is possible to suppress damage to the powder core 10 around the lead portion 22 after the press forming. As a result, it is possible to suppress a decrease in the reliability of the inductor 100.

[0145] Alternatively, the lead portion 22 may have a rectangular cross section perpendicular to the lead direction Dr having a long side 23a and a short side 24a, and a length L of a notch along the lead direction Dr may be 0.5 to 1.5 times the length of the long side 23a.

[0146] Thus, the lead portion 22 has a structure that is easy to twist, and for example, the force in the twisting direction generated in the lead portion 22 during press forming can be reduced. Therefore, it is possible to suppress shear damage to the wire at the portion connecting the electrode portion 27 and the lead portion 22. In addition, the residual stress in the twisting direction remaining in the lead portion 22 can be reduced, and the powder core 10 around the lead portion 22 after press forming can be suppressed from being damaged. As a result, it is possible to suppress a decrease in the reliability of the inductor 100.

[0147] Furthermore, the length L of the notch along the lead-out direction Dr may be longer than the width w of the notch.

[0148] Thus, the lead portion 22 has a structure that is easy to twist, and for example, the force in the twisting direction generated in the lead portion 22 during press forming can be reduced. Therefore, it is possible to suppress shear damage to the wire at the portion connecting the electrode portion 27 and the lead portion 22. In addition, the residual stress in the twisting direction remaining in the lead portion 22 can be reduced, and the powder core 10 around the lead portion 22 after press forming can be suppressed from being damaged. As a result, it is possible to suppress a decrease in the reliability of the inductor 100.

[0149] Furthermore, the width of the center portion Ntc of the notch in the extension direction Dr of the notch Nt may be narrower than the width of the end portion Nte of the notch.

[0150] Thus, by setting the shape in which the width of the central portion Ntc of the notch is narrower than that of the end portion Nte, for example, the force in the torsional direction generated in the lead portion 22 during press forming can be absorbed. Therefore, it is possible to suppress shear damage to the wire at the portion connecting the electrode portion 27 and the lead portion 22. In addition, the residual stress in the torsional direction remaining in the lead portion 22 can be reduced, and the powder core 10 around the lead portion 22 after press forming can be suppressed from being damaged. As a result, it is possible to suppress a decrease in the reliability of the inductor 100.

[0151] Furthermore, the depth dp of the notch may be not less than 1.0 times and not more than 3.0 times the width w of the notch.

[0152] Thus, the lead portion 22 has a structure that is easy to twist, and for example, the force in the twisting direction generated in the lead portion 22 during press forming can be reduced. Therefore, it is possible to suppress shear damage to the wire at the portion connecting the electrode portion 27 and the lead portion 22. In addition, the residual stress in the twisting direction remaining in the lead portion 22 can be reduced, and the powder core 10 around the lead portion 22 after press forming can be suppressed from being damaged. As a result, it is possible to suppress a decrease in the reliability of the inductor 100.

[0153] Furthermore, the center portion Ntc of the notch in the extension direction Dr of the notch Nt may be deeper than the end portion Nte of the notch.

[0154] Thus, the lead portion 22 has a structure that is easy to twist, and for example, the force in the twisting direction generated in the lead portion 22 during press forming can be reduced. Therefore, it is possible to suppress shear damage to the wire at the portion connecting the electrode portion 27 and the lead portion 22. In addition, the residual stress in the twisting direction remaining in the lead portion 22 can be reduced, and the powder core 10 around the lead portion 22 after press forming can be suppressed from being damaged. As a result, it is possible to suppress a decrease in the reliability of the inductor 100A.

[0155] The lead portion 22 has a rectangular cross section perpendicular to the lead direction Dr and has long sides 23a, 23b and short sides 24a, 24b. Notches Nt may be provided on the long sides 23a, 23b and the short sides 24a, 24b.

[0156] Thus, the lead portion 22 formed by the four notches Nt has a cross-sectional shape that is easy to twist, and for example, the force in the twisting direction generated in the lead portion 22 during press forming can be reduced. Therefore, it is possible to suppress shear damage to the wire at the portion connecting the electrode portion 27 and the lead portion 22. In addition, the residual stress in the twisting direction remaining in the lead portion 22 can be reduced, and the powder core 10 around the lead portion 22 after press forming can be suppressed from being damaged. As a result, it is possible to suppress a decrease in the reliability of the inductor 100C.

[0157] Alternatively, the lead portion 22 may have a rectangular cross section perpendicular to the lead direction and have two long sides 23a, 23b and two short sides 24a, 24b. The notch Nt is provided in the long side 23a farther from the center 21c of the wound body 21 of the two long sides.

[0158] For example, the insulating film is removed at the portion where the notch Nt is formed, and the conductor material is exposed. However, by providing the notch Nt at the long side 23a farther from the center 21c of the wound body 21, the notch Nt can be moved away from the wound body 21. Thus, the notch Nt can be prevented from affecting the characteristics of the inductor 100, and the reliability of the inductor 100 can be prevented from being reduced.

[0159] In addition, the cross section of the lead-out portion 22 perpendicular to the lead-out direction may be a rectangular shape having two long sides 23a, 23b and two short sides 24a, 24b. The notch Nt is provided in the long side 23a of the two long sides which is farther from the center 21c of the winding body 21 and the short side 24a of the two short sides which is farther from the winding axis AT of the winding body 21.

[0160] For example, the insulating film is removed from the portion where the notch Nt is formed, and the conductor material is exposed. However, by providing the notch Nt at the long side 23a farther from the center 21c of the wound body 21, the notch Nt can be separated from the wound body 21. In addition, by providing the notch Nt at the short side 24a farther from the winding axis AT, the notch Nt can be separated from the wound body 21. Thus, the notch Nt can be prevented from affecting the characteristics of the inductor 100D, and the reliability of the inductor 100D can be prevented from being reduced.

[0161] In addition, the notch Nt may be provided between the midpoint 22m of the lead-out portion 22 in the lead-out direction Dr and the third surface 13c.

[0162] For example, the insulating film is removed at the portion where the notch Nt is formed, and the conductor material is exposed. However, by providing the notch Nt between the midpoint 22m of the lead portion 22 and the third surface 13c, the notch Nt can be kept away from the wound body 21. Thus, the notch Nt can be prevented from affecting the characteristics of the inductor 100E, and the reliability of the inductor 100D can be prevented from being reduced.

[0163] In addition, the third surface may be composed of multiple third surfaces 13a, 13b, 13c, and 13d, the lead portion 22 may be composed of multiple lead portions 22, the electrode portion 27 may be composed of multiple electrode portions 27, and the multiple electrode portions 27 may protrude from the same third surface 13c among the multiple third surfaces 13a~13d.

[0164] Thus, for example, the wound body portion 21 is easily inclined relative to the electrode portion 27 during press forming, but even with such a structure, the force in the torsional direction generated in the lead portion 22 can be reduced. Therefore, it is possible to suppress shear damage to the wire at the portion connecting the electrode portion 27 and the lead portion 22. In addition, the residual stress in the torsional direction remaining in the lead portion 22 can be reduced, and the powder core 10 around the lead portion 22 after press forming can be suppressed from being damaged. As a result, it is possible to suppress a decrease in the reliability of the inductor 100.

[0165] The method for manufacturing an inductor according to the present embodiment includes: a coil element forming step of forming a coil element 20 having a winding body 21 wound with a flat wire; and a powder core forming step of placing a part of the coil element 20 and a magnetic material in a mold 90 and performing press molding to form a powder core 10 including the coil element 20. In the powder core forming step, the press molding is performed in such a manner that the winding body 21 and the lead-out portion 22 led out from the end of the winding body 21 are provided inside the powder core 10 and the electrode portion 27 connected to the lead-out portion 22 is provided outside the powder core 10. In the coil element forming step, a notch Nt is formed along the lead-out direction Dr of the lead-out portion 22 at a position that becomes the lead-out portion 22 in the powder core forming step.

[0166] In this way, by providing the notch Nt in the lead-out portion 22 of the coil element 20, the lead-out portion 22 is easily twisted. As a result, the force in the twisting direction generated in the lead-out portion 22 due to the inclination of the winding body portion 21 relative to the electrode portion 27 during stamping can be reduced. Therefore, it is possible to suppress shear damage to the wire at the portion connecting the electrode portion 27 and the lead-out portion 22. In addition, the residual stress in the twisting direction remaining in the lead-out portion 22 can be reduced, and the powder core 10 around the lead-out portion 22 after stamping can be suppressed from being damaged. As a result, the reliability of the inductor 100 can be suppressed from being reduced.

[0167] Furthermore, the width of the center portion Ntc of the notch in the lead-out direction Dr may be narrower after the powder magnetic core forming step than before the powder magnetic core forming step.

[0168] In this way, the twist is made in the central part Ntc of the notch, and the width becomes narrower after the powder core forming step than before the powder core forming step, and the force in the twisting direction generated in the lead portion 22 during the stamping process can be absorbed. Therefore, it is possible to suppress shear damage of the wire at the part connecting the electrode portion 27 and the lead portion 22. In addition, the residual stress in the twisting direction remaining in the lead portion 22 can be reduced, and the powder core 10 around the lead portion 22 after stamping can be suppressed from being damaged. As a result, it is possible to suppress the reliability of the inductor 100 from being reduced.

[0169] (Other Implementations, etc.)

[0170] The above describes the inductor and the like according to the embodiments and variations of the present disclosure, but the present disclosure is not limited to the above embodiments and variations. As long as it does not deviate from the main purpose of the present disclosure, various forms after the embodiments and variations are applied to the embodiments and variations that can be thought of by those skilled in the art, and other forms constructed by combining some of the constituent elements of the embodiments and variations are also included in the scope of the present disclosure.

[0171] In the above embodiment, the cross section of the notch Nt is described as a V-shaped example, but the notch Nt is not limited to this, and the cross section of the notch Nt may also be U-shaped. In addition, the notch Nt is not limited to the incision process, and may also be formed by removal processing such as laser or cutting tool.

[0172] In addition, for example, electrical products or circuits using the above-mentioned inductor are also included in the present disclosure. As the electrical product, there can be mentioned a power supply device having the above-mentioned inductor or various devices having the power supply device.

[0173] Industrial Applicability

[0174] The inductor according to the present disclosure is useful as an inductor used in various devices and equipment.

[0175] Description of symbols

[0176] 10Powder core

[0177] 11 Page 1

[0178] 12 Page 2

[0179] 13a, 13b, 13c, 13d, side 3

[0180] 20 coil elements

[0181] 21 winding body

[0182] 21a One end

[0183] 21b The other end

[0184] 21c Center

[0185] 22 Lead-out section

[0186] 22m midpoint

[0187] 23a, 23b Long side

[0188] 24a, 24b short side

[0189] 27 Electrode

[0190] 28a, 28b long side

[0191] 29a, 29b short side

[0192] 90 mold

[0193] 91, 92 Punch

[0194] 93, 94 mold

[0195] 100, 100A, 100B, 100C, 100D, 100E, 100F inductors

[0196] AT winding shaft

[0197] dp, dp1, dp2 notch depth

[0198] Dr leads to the direction

[0199] L notch length

[0200] Nt Gap

[0201] Ntc Central

[0202] Nte end

[0203] w, w1, w2 The width of the gap

Claims

1. An inductor, comprising: A powder magnetic core having a first surface, a second surface opposite to the first surface, and at least one third surface connecting the first surface and the second surface; and Coil components, made of flat wire; The coil element comprises a winding body portion located inside the powder magnetic core, a lead portion led out from an end of the winding body portion toward the third surface, and an electrode portion connected to the lead portion and protruding from the third surface toward the outside of the powder magnetic core; The lead-out portion has a notch along a lead-out direction of the lead-out portion.

2. The inductor according to claim 1, wherein: The notch is a groove arranged along the lead-out direction.

3. The inductor according to claim 2, wherein: A cross section of the groove perpendicular to the lead-out direction is V-shaped.

4. The inductor according to claim 1, wherein: The notch is a through hole arranged along the lead-out direction.

5. The inductor according to any one of claims 1 to 4, wherein: The notch is in contact with the third surface.

6. The inductor according to any one of claims 1 to 4, wherein: The cross section of the lead-out portion perpendicular to the lead-out direction is a rectangular shape having a long side and a short side; The notch is arranged at the center of the long side.

7. The inductor according to any one of claims 1 to 4, wherein: When viewed from the lead-out direction, The cross section of the lead-out portion is a rectangular shape; The cross section of the electrode portion is a rectangular shape; The long side of the lead portion and the long side of the electrode portion intersect with each other.

8. The inductor according to any one of claims 1 to 4, wherein: The cross section of the lead-out portion perpendicular to the lead-out direction is a rectangular shape having a long side and a short side; The length of the notch along the leading direction is not less than 0.5 times and not more than 1.5 times the length of the long side.

9. The inductor according to any one of claims 1 to 4, wherein: The length of the notch along the lead-out direction is longer than the width of the notch.

10. The inductor according to any one of claims 1 to 4, wherein: A central portion of the notch in the leading direction of the notch has a narrower width than end portions of the notch.

11. The inductor according to any one of claims 1 to 3, wherein: The depth of the notch is not less than 1.0 times and not more than 3.0 times the width of the notch.

12. The inductor according to any one of claims 1 to 3, wherein: A center portion of the notch in the leading direction of the notch is deeper than end portions of the notch.

13. The inductor according to any one of claims 1 to 3, wherein: The cross section of the lead-out portion perpendicular to the lead-out direction is a rectangular shape having a long side and a short side; The notches are respectively arranged on the long side and the short side.

14. The inductor according to any one of claims 1 to 3, wherein: The cross section of the lead-out portion perpendicular to the lead-out direction is a rectangular shape having two long sides and two short sides; The notch is provided on the long side of the two long sides which is farther from the center of the winding body.

15. The inductor according to any one of claims 1 to 3, wherein: The cross section of the lead-out portion perpendicular to the lead-out direction is a rectangular shape having two long sides and two short sides; The notch is provided on the long side of the two long sides which is farther from the center of the winding body and on the short side of the two short sides which is farther from the winding axis of the winding body.

16. The inductor according to any one of claims 1 to 4, wherein: The notch is provided between a midpoint of the lead-out portion in the lead-out direction and the third surface.

17. The inductor according to any one of claims 1 to 4, wherein: The third surface is composed of a plurality of the third surfaces; The lead-out portion is composed of a plurality of the lead-out portions; The electrode portion is composed of a plurality of electrode portions; The plurality of electrode portions protrude from the same third surface among the plurality of third surfaces.

18. A method for manufacturing an inductor, comprising: a coil element forming step of forming a coil element having a winding body portion wound with a flat wire; as well as a powder magnetic core forming step of placing a part of the coil element and a magnetic material into a mold and performing press molding to form a powder magnetic core including the coil element; In the powder magnetic core forming step, the pressed magnetic core is formed by providing the wound body and the lead-out portion led out from the end of the wound body inside the powder magnetic core, and providing an electrode portion connected to the lead-out portion outside the powder magnetic core; In the coil element forming step, a notch is formed along a leading direction of the lead portion at a position that becomes the lead portion in the powder magnetic core forming step.

19. The method for manufacturing an inductor according to claim 18, wherein: The width of the center portion of the notch in the extraction direction is narrower after the powder magnetic core forming step than before the powder magnetic core forming step.

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