Inductor and method for manufacturing inductor

Abstract

The present invention is provided with a magnetic core (11) obtained by mixing and press-molding a magnetic material powder and a binder, a coil element (12) embedded in the magnetic core (11), and an electrode member (13) electrically and mechanically connected to an end portion (12a) of the coil element, the end portion (12a) of the coil element being overlapped on the electrode member (13) provided on an end surface (11a) of the magnetic core and connected to the electrode member (13) at a caulking portion (13d). The staked portion (13d) is embedded in the magnetic core (11), an end surface portion (13a) of the electrode member (13) on the end surface (11a) side of the magnetic core is embedded in the magnetic core (11) by at least a portion of the thickness thereof and fixed, and a bottom surface portion (13b) of the electrode member (13) on the bottom surface (11b) side of the magnetic core is not fixed to the magnetic core (11).

Description

Technical Field

[0001] The present invention relates to an inductor used in various electronic devices and a method for manufacturing the inductor. Background Art

[0002] In recent years, as the performance of electronic devices has improved, there is a trend towards miniaturization and increased current used, and an inductor that satisfies both is in demand. Furthermore, for inductors used in harsh environments such as automotive applications, vibration resistance and heat cycle resistance are also required. For this reason, an inductor has been proposed in which a coil element is buried in a mixed powder of a metal magnetic body powder and a binder composed of a thermosetting resin and pressed to form a magnetic core.

[0003] In order to reduce the cost of forming the external electrodes, there has been a proposal to simultaneously mold the components that will serve as the external electrodes when forming the magnetic core.

[0004] In addition, as prior art document information related to the invention of the present application, for example, Patent Document 1 and Patent Document 2 are known.

[0005] Prior Art Literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2012-230972

[0008] Patent Document 2: Japanese Patent Application Publication No. 2005-294461 Summary of the invention

[0009] Problems to be solved by the invention

[0010] However, inductors used in harsh environments such as automotive applications are required to have vibration resistance and heat cycle resistance.

[0011] An object of the present invention is to provide an inductor or the like which is compact, can support high power, and has excellent vibration resistance and heat cycle resistance.

[0012] Means for solving problems

[0013] An inductor according to one embodiment of the present invention comprises: a magnetic core, which is pressurized by mixing magnetic material powder and a binder, and has a bottom surface and an end surface connected to the bottom surface; a coil element, which is buried in the magnetic core; and an electrode component, which is electrically and mechanically connected to the end of the coil element, the electrode component is bent from the end surface of the magnetic core toward the bottom surface of the magnetic core, the electrode component has a rivet portion, the end of the coil element is overlapped with the electrode component and riveted at the rivet portion, the riveted portion is welded to be electrically and mechanically connected, the rivet portion is buried in the magnetic core, the electrode component on the end surface side of the magnetic core is fixed by being buried in the magnetic core through at least a portion of the thickness, and the electrode component on the bottom surface side of the magnetic core is not fixed to the magnetic core.

[0014] In a manufacturing method of an inductor involved in one embodiment of the present invention, the inductor has a coil element buried in a magnetic core having a bottom surface and an end surface connected to the bottom surface, and the end of the coil element is electrically and mechanically connected to an electrode component. The manufacturing method includes: a step of forming a coil element in which a conductive wire with an insulation coating on the surface is spirally wound and the two ends are led out in opposite directions and the insulation coating of the end is peeled off; a step of preparing an electrode component composed of a rivet portion, an end surface portion, a bottom surface portion and a supporting portion; a riveting step of overlapping the end of the coil element with a part of the electrode component and riveting at the rivet portion to fix the end of the coil element to the electrode component; and a welding step of irradiating the riveted portion with a laser to integrate the coil element with the electrode component. ; a process of bending the end of the coil element or the electrode component; a process of mixing magnetic material powder with resin and molding to obtain an upper magnetic powder plate and a lower magnetic powder plate; a magnetic core forming process, after placing the upper magnetic powder plate into the mold, inserting a component formed by integrating the coil element and the electrode component, placing the lower magnetic powder plate thereon and press-molding to form the magnetic core; and an electrode forming process, cutting off the supporting portion of the electrode component and bending the bottom surface portion to form an electrode, the rivet portion being buried in the magnetic core, the electrode component on the end surface side of the magnetic core being fixed by being buried in the magnetic core through at least a portion of the thickness, and the electrode component on the bottom surface side of the magnetic core being not fixed to the magnetic core.

[0015] Effects of the Invention

[0016] With the above configuration, it is possible to provide an inductor or the like having excellent vibration resistance and heat cycle resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a perspective view of an inductor according to one embodiment of the present invention.

[0018] Figure 2It is a cross-sectional view of an inductor according to one embodiment of the present invention.

[0019] Figure 3 1 is a flowchart showing a method for manufacturing an inductor according to one embodiment of the present invention.

[0020] Figure 4 This is a diagram for explaining a part of a method for manufacturing an inductor according to an embodiment of the present invention.

[0021] Figure 5 This is a perspective view of another inductor according to one embodiment of the present invention.

[0022] Figure 6 yes Figure 5 An oblique view of a portion of another inductor is shown.

[0023] Figure 7 It is a diagram for explaining a part of a method for manufacturing still another inductor according to one embodiment of the present invention.

[0024] Figure 8 This is a diagram for explaining a part of a method for manufacturing an inductor according to an embodiment of the present invention.

[0025] Fig. 9 This is a diagram for explaining a part of a method for manufacturing an inductor according to an embodiment of the present invention.

[0026] Fig.10 This is a diagram for explaining a part of a method for manufacturing an inductor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] Hereinafter, an inductor according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 is a perspective view of an inductor according to one embodiment of the present invention, Figure 2 is a cross-sectional view of the inductor. In addition, for easy observation, Figure 1 The outer shape of the magnetic core is represented by a dotted line. Figure 2 This is a cross section when the inductor is cut along a plane that passes through both ends of the coil element and is perpendicular to the bottom surface of the magnetic core.

[0028] The coil element 12 is an element formed by winding an insulating coated wire with a diameter of approximately 0.3 mm. The end 12a of the coil element has the insulating coating peeled off and is flattened to a flat shape with a thickness of approximately 0.2 mm. The coil element 12 is embedded in a magnetic material powder formed by mixing a magnetic material powder composed of a Fe-Si-Cr alloy and a binder composed of silicone, and then press-formed to form a magnetic core 11. The magnetic core 11 is a rectangular parallelepiped with a planar shape of approximately 10 mm square and a height of approximately 5 mm, and has a bottom surface 11b of the magnetic core and an end surface 11a of the magnetic core connected to the bottom surface 11b of the magnetic core. An electrode component 13 is fixed to the end surface 11a of the magnetic core. The electrode component 13 is bent along the bottom surface 11b of the magnetic core and is composed of an end surface portion 13a and a bottom surface portion 13b.

[0029] The electrode component 13 on the end face 11a side of the magnetic core is fixed by being buried in the magnetic core 11 through at least a part of the thickness, and the electrode component 13 on the bottom face 11b side of the magnetic core is not fixed to the magnetic core 11. The electrode component 13 has a rivet portion 13d at the front end of the end face portion 13a, and the end 12a of the coil element is overlapped on the electrode component 13, and the rivet portion 13d is bent and pressed toward the end 12a of the coil element to be riveted, and the rivet portion 13d is welded to the end 12a of the coil element to be electrically and mechanically connected. The rivet portion 13d is buried in the inside of the magnetic core 11 in a manner facing the center direction of the magnetic core 11. By burying the riveted and welded part in the inside of the magnetic core 11 in this way, the electrode component 13 is not easy to peel off from the magnetic core 11, which can improve reliability.

[0030] In addition, a notch 12b is provided at the end 12a of the coil element between the winding portion and the rivet portion 13d of the coil element 12, and the end 12a of the coil element is bent at the notch 12b. If the bent portion in the area buried in the magnetic core changes, the shape of the coil element is also easily deformed, and thus the electrical characteristics such as the inductance value are easily deviated. Therefore, by providing the notch 12b at the end 12a of the coil element in advance, the shape of the coil element can be stabilized by bending at the notch 12b, and the electrical characteristics can be stabilized. Usually, the notch is provided to make it easy to bend, but the mechanical strength is easily deteriorated due to the provision of the notch. In contrast, in the inductor of the present embodiment, the portion that is bent by providing the notch 12b is buried in the magnetic core 11 and fixed, so that the mechanical strength can be maintained even if the notch 12b is provided.

[0031] The electrode component 13 is a component that is punched out of a flat copper plate containing more than 99% copper, and has a thickness of approximately 0.15 mm. A plating layer 13f plated in the order of nickel and tin is provided on the surface of one side of the electrode component 13, and the surface on the other side is in a state where the copper is exposed. The surface of the electrode component 13 on the end face 11a side of the magnetic core that is not provided with the plating layer is opposite to the magnetic core 11. On the other hand, the electrode component 13 on the surface opposite to the surface opposite to the magnetic core 11 is provided with the plating layer 13f, so it is easy to solder to the mounting substrate. In addition, the electrode component 13 on the surface opposite to the magnetic core 11 has no plating layer, so even when the solder reflows and other conditions reach a high temperature, the bonding strength between the magnetic core 11 and the electrode component 13 can be maintained.

[0032] Furthermore, since the electrode member 13 on the end face 11a side of the magnetic core is embedded and fixed in the magnetic core 11, the vibration resistance can be improved. On the other hand, since the electrode member 13 on the bottom face 11b side of the magnetic core is not fixed to the magnetic core 11, even if the thermal expansion coefficient of the mounting substrate and the inductor is different, the influence of the elongation caused by the thermal cycle can be alleviated, and the heat cycle resistance can be improved.

[0033] The bottom surface 11b of the magnetic core (at Figure 2 The extended line of the bottom surface 11b of the magnetic core is shown by the dotted line in the figure) and the end surface portion 11c of the electrode component on the end surface 11a side of the magnetic core (in Figure 2 The angle formed by the bottom surface 11b of the magnetic core and the end surfaces 11a' of the magnetic core on both sides of the electrode member 13 (indicated by a dashed line in FIG. 1 ) is set to approximately 86.5°. Figure 2 The angle formed by the end faces 11a' of the magnetic core on both sides of the electrode component (indicated by the two-dot chain line) is set to approximately 89.5°. In addition, the reference plane of the bottom surface 11b of the magnetic core at this time means the surface placed on the flat plate in the state where the electrode component 13 on the bottom surface 11b side of the magnetic core is removed. The angle formed by the bottom surface 11b of the magnetic core and the end faces 11a' of the magnetic core on both sides of the electrode component 13 is set to approximately 89.5°, which is smaller than 90.0°, in order to add a slight tilt to facilitate the extraction of the magnetic core 11 from the mold during press molding. In addition, the tilt is the tilt based on the line along the pressing direction during press molding, in other words, it is the tilt relative to the line perpendicular to the bottom surface 11b of the magnetic core.

[0034] When the magnetic core is placed in a mold and subjected to pressure molding, the entire magnetic core expands when the magnetic core is taken out. Therefore, the electrode component arranged on the end face side of the magnetic core is also pressed by the wall of the mold with strong stress and is easily damaged. In contrast, in one embodiment of the present invention, the end faces 11a' of the magnetic core on both sides of the electrode component on the end face 11a side of the magnetic core are at an angle closer to a right angle to the bottom face 11b of the magnetic core than the end face portion 13a of the electrode component. Therefore, even if the magnetic core 11 expands as a whole, the end faces 11a' of the magnetic core on both sides of the electrode component on the end face 11a side of the magnetic core provide support to suppress the expansion of the surface 11c of the end face portion of the electrode component. Therefore, the end face portion 13a of the electrode component 13 on the end face 11a side of the magnetic core can be made less susceptible to damage. Here, the inclination of the end face portion 13a of the electrode component 13 is larger than the end faces 11a' of the core on both sides of the electrode component. Therefore, the pressure that expands toward the end face 11a of the core during press molding is dispersed along the inclination, thereby suppressing the expansion of the entire core 11.

[0035] It is preferred that the angle formed by the surface 11c of the end face portion of the electrode component on the end face 11a side of the core and the end faces 11a' of the core on both sides of the electrode component be set to be greater than 2.0° and less than 5.0°. If the angle is smaller than 2.0°, the effect of suppressing damage to the electrode component 13 becomes smaller, and if it is larger than 5.0°, when the electrode component 13 is bent from the end face 11a of the core toward the bottom face 11b of the core, the core 11 is prone to cracks, which is not preferred.

[0036] In addition, the end face portion 13a of the electrode component 13 is tapered relative to the mounting surface, so when the inductor is mounted and soldered, the solder is easily wetted upward. Thus, an inductor with excellent solderability can be provided. In addition, the end face portion 13a of the electrode component 13 is tapered relative to the mounting surface, so it is easy to check the soldering state from above.

[0037] Next, a method for manufacturing an inductor according to one embodiment of the present invention will be described.

[0038] Figure 3 FIG. 1 is a flow chart showing a method for manufacturing an inductor according to an embodiment of the present invention. Figure 3 As shown, the manufacturing method of the inductor includes: a step S110 of forming a coil element, a step S115 of forming a notch portion at the end of the coil element, a step S120 of preparing an electrode component, a riveting step S130 of fixing the end of the coil element to the electrode component, a welding step S140 of integrating the coil element and the electrode component, a step S150 of bending the end of the coil element or the electrode component, a step S160 of obtaining an upper magnetic powder plate and a lower magnetic powder plate, a magnetic core forming step S170 and an electrode forming step S180.

[0039] In addition, the order of steps S110, S120, and S160 may be different. Step S115 may be performed simultaneously with step S110. Step S115 may be performed before step S150. Step S160 may be performed before step S130. Each step is described below.

[0040] First, a coil element 12 is formed by spirally winding a conductive wire with an insulation coating on the surface and leading both ends in opposite directions. The conductive wire uses an insulation-coated copper wire with a diameter of approximately 0.3 mm, and the insulation coating is peeled off at the end 12a of the coil element, and it is flattened to a thickness of approximately 0.2 mm.

[0041] On the other hand, the electrode member 13 is obtained by punching a flat plate having a plated layer 13f of nickel and tin in this order on the surface of one side of a copper plate containing 99% or more of copper. The electrode member 13 is formed integrally with an end face portion 13a, a bottom face portion 13b, and a support portion 13c. The end face portion 13a is a portion arranged on the end face 11a of the magnetic core and connected to the end 12a of the coil element, the bottom face portion 13b is a portion connected to the end face portion 13a and arranged on the bottom face 11b of the magnetic core, and the support portion 13c is a portion connected to the bottom face portion 13b on the opposite side of the end face portion 13a and supported by a mold when the magnetic core 11 is press-formed as described later. The thickness of the electrode member 13 is approximately 0.15 mm.

[0042] Figure 4 This is a diagram for explaining a part of a method for manufacturing an inductor according to an embodiment of the present invention.

[0043] Figure 4 (a) is a plan view of the electrode component 13, in which the support portion 13c, the bottom portion 13b and the end portion 13a are connected in a straight line, and a rivet portion 13d is provided at the front end of the end portion 13a on the opposite side of the bottom portion 13b. The end portion 12a of the coil element overlaps with the rivet portion 13d, as shown in FIG. Figure 4As shown in (b), the rivet portion 13d is folded back and overlapped with the end portion 12a of the coil element and riveted, so that the end portion 12a of the coil element is pressed together with the electrode component 13 and temporarily fixed. At this time, the front end portion of the end portion 12a of the coil element is riveted in a manner overlapping with the electrode component 13, and the front end portion of the end portion 12a of the coil element protrudes from the rivet portion 13d. That is, the front end portion of the end portion 12a of the coil element is in a state of protruding from the rivet portion 13d. Here, the length of the rivet portion 13d is set to approximately 1.0mm, and the length of the front end portion of the end portion 12a of the coil element protruding from the rivet portion 13d is set to approximately 0.3mm. In addition, each length refers to the length of the end portion 12a of the coil element in the extension direction.

[0044] Next, the caulking portion 13d is folded back and overlapped with the end portion 12a of the coil element, that is, the caulking portion 13d is folded back and overlapped with the end portion 12a of the coil element. Figure 4 The laser irradiation position 16 indicated by the dotted line in (b) is scanned in a zigzag manner across the extension direction of the end 12a of the coil element, and the laser is irradiated from the coil element 12 side toward the front end, welding the electrode member 13 and the end 12a of the coil element to form a Figure 4 (c) is shown. At this time, the front end of the end 12a of the coil element is not irradiated with laser, but the heat generated by the irradiation of laser is transferred to the front end of the end 12a of the coil element, and the front end becomes a melted and solidified state, and the edge of the front end of the end 12a of the coil element becomes a rounded shape. The riveted portion 13d can be in various states of a state before riveting, a state after riveting, and a melted and solidified state.

[0045] In addition, Figure 1 In the embodiment, the end 12a of the coil element is led out to the opposite end surface side and is clamped and fixed by the rivet portion 13d of the electrode member 13, but it can also be as follows Figure 5 and Figure 6 shown.

[0046] Figure 5 This is a perspective view of another inductor according to one embodiment of the present invention. Figure 6 yes Figure 5 An oblique view of a portion of another inductor is shown. Figure 6 In (a), the rivet portion 13d is shown as being fixed to the end portion 12a of the coil element by rivet (the state before welding). Figure 6 (b) shows a state where the rivet portion 13d is welded to the end portion 12a of the coil element. Figure 5 In the inductor, Figure 6 The swaged portion 13 d (a part of the electrode member 13 ) in the welded state shown in FIG. 1 (b) is buried in the magnetic core 11 .

[0047] exist Figure 5 and Figure 6 In the embodiment, the ends 12a of the coil elements are led out in the directions of the corners which are diagonally opposite to each other when looking down at the magnetic core 11, and the rivet portions 13d of the electrode components 13 are wound around the ends 12a of the coil elements for rivet fixing. In this way, by leading out the ends 12a of the coil elements in the directions of the opposite corners and connecting them to the electrode components 13, the magnetic core 11 can be effectively used, the overlapping characteristics can be improved, and since the ends 12a of the coil elements extend toward the corners of the magnetic core 11, the connection can be made at a shorter distance, and the DC resistance can be reduced.

[0048] In addition, it is preferable to set the width w2 of the electrode member 13 at the bent portion on the bottom surface 11b side of the magnetic core to be narrower than the width w1 at both ends of the electrode member 13 at the portion protruding from the magnetic core 11. By reducing the width w2 of the electrode member 13 at the bent portion on the bottom surface 11b side of the magnetic core 11, the amount of solder during mounting can be reduced, and by increasing the width w1 at both ends of the electrode member 13 at the portion protruding from the magnetic core 11, the detachment strength of the electrode member 13 from the magnetic core can be increased.

[0049] Figure 7 It is a diagram for explaining a part of a method for manufacturing still another inductor according to one embodiment of the present invention. Figure 7 express Figure 4 (c) is another example of the welding state between the electrode member 13 and the end portion 12a of the coil element.

[0050] like Figure 7 As shown, it is more preferred that the area of ​​the riveting portion 13d opposite to the front end of the end 12a of the coil element also becomes a melted and solidified state. Furthermore, the riveting portion 13d and the end 12a of the coil element riveted to the riveting portion 13d can also be completely melted to form a solder ball. In this way, the end 12a of the coil element can be more reliably connected to the electrode component 13 in an electrical and mechanical manner, and it can be confirmed from the appearance that it is reliably connected.

[0051] By embedding the welded portion into the interior of the magnetic core 11, the electrode component 13 is firmly fixed to the magnetic core 11, which can improve reliability. However, after the magnetic core 11 is formed, the welding state cannot be confirmed. Therefore, it is preferred to perform image recognition on the front end of the end 12a of the coil element after riveting and welding, and perform image recognition and confirmation again after the welding process, so as to confirm that the front end of the coil element is in a molten and solidified state. In this way, it is possible to proceed to the next process on the basis of confirming that the welding is reliably performed before the welded portion is embedded in the magnetic core 11, which can improve reliability. Here, as confirmation that the front end of the coil element is in a molten and solidified state, it can be cited as: confirming that the corner of the front end before welding disappears and changes to a rounded state, or confirming the change in color tone of the front end before and after welding, etc.

[0052] The length of the front end of the end 12a of the coil element protruding from the rivet portion 13d is preferably set to be greater than 0.05 mm and less than two-thirds of the length of the rivet portion 13d. This is because if the protruding length is shorter than 0.05 mm, it is difficult to confirm the front end of the end 12a of the coil element by image recognition in the riveted state, and if it is longer than two-thirds of the length of the rivet portion 13d, heat cannot be fully transferred to the front end of the end 12a of the coil element and it is difficult to melt.

[0053] Next, a step is performed to bend the end 12a of the coil element and the electrode member 13. In this step, preparations are made so that the end surface portion 13a of the coil element 12 and the electrode member 13, which are connected and integrated by the coil element 12 and the electrode member 13, are placed in the cavity of the mold for press-molding the magnetic core 11 described later.

[0054] Figure 8 This is a diagram for explaining a part of a method for manufacturing an inductor according to an embodiment of the present invention.

[0055] First, the notch portion 12 b is provided at the end portion 12 a of the coil element 12 between the wound portion and the riveted portion. Figure 8 (a) is a cross-sectional view showing a state where the electrode member 13 is welded to the end portion 12a of the coil element. Figure 8 As shown in (b), a notch 12b is provided at the end 12a of the coil element between the winding portion and the riveted portion of the coil element 12 by using a mold or the like. Then, the end 12a of the coil element is bent starting from the notch 12b to form Figure 8 as shown in (c).

[0056] If the bent portion in the area buried in the magnetic core changes, the shape of the coil element is also easily deformed, and thus the electrical characteristics such as the inductance value are easily deviated. Therefore, by providing the notch portion 12b at the end 12a of the coil element in advance, the shape of the coil element can be stabilized by bending at the notch portion 12b, and the electrical characteristics can be stabilized. Usually, the notch portion is provided to make it easy to bend, but the mechanical strength is easily deteriorated due to the provision of the notch portion. In contrast, in the inductor of this embodiment, the portion bent by providing the notch portion 12b is buried in the magnetic core 11 and fixed, so that the mechanical strength can be maintained even if the notch portion 12b is provided.

[0057] In the present embodiment, the conductor uses an insulating coated copper wire with a diameter of approximately 0.3 mm, which is flattened to form a flat shape with a thickness of approximately 0.2 mm. A notch 12b with a depth of approximately 0.1 mm is provided in the portion flattened to form a flat shape. The depth of the notch 12b is preferably set to be greater than 40% and less than 70% of the thickness of the end 12a of the coil element around the notch 12b. If the depth of the notch 12b is less than 40% of the thickness of the end 12a of the coil element around the notch 12b, it is difficult to bend stably. On the other hand, if the depth of the notch 12b is deeper than 70% of the thickness of the end 12a of the coil element around the notch 12b, the strength is likely to be weakened in situations including transportation.

[0058] The step of forming the notch portion may be performed before the bending. For example, the notch portion may be formed simultaneously when the end portion of the coil element is processed into a flat shape.

[0059] The shape of the notch 12b is as follows: Figure 8 When observing the cross section shown in (b), it can be set to a triangle, a semicircle, a trapezoid or the like, but from the viewpoint of being easy to bend, it is more preferably set to a triangle. Wherein, in the case of being set to a triangle, it is preferred to set a curved portion at its vertex. In this case, the angle of the vertex is preferably set to 90°±30°. This is because if the angle is too small, problems such as the life of the mold are prone to occur. On the other hand, if the angle is too large, the starting point of the bend is prone to deviation.

[0060] Fig. 9 This is a diagram for explaining a part of a method for manufacturing an inductor according to an embodiment of the present invention.

[0061] The state of the magnetic core 11 as a component formed by integrating the coil element 12 and the electrode component 13 during press molding is as follows: Fig. 9 As shown, the coil element is bent at the end 12 a , the end surface portion 13 a and the bottom surface portion 13 b form a straight line, and the supporting portion 13 c is bent outward relative to the coil element 12 .

[0062] In addition, Figure 8 In the embodiment, the end 12a of the coil element is bent after the electrode member 13 is fixed to the end 12a of the coil element. Figure 5 and Figure 6 In the case of the structure shown, after the electrode member 13 is bent into a predetermined shape, the caulking portion 13 d of the electrode member may be caulked and fixed to the end portion 12 a of the coil element.

[0063] On the other hand, preparations are made for forming the magnetic core 11. First, a pressed magnetic powder is used, which is a mixture of a magnetic material powder composed of an Fe-Si-Cr alloy and a binder composed of silicone. The pressed magnetic powder is first placed in a plate forming mold and pressed at a pressure of approximately 0.25 tons / cm 2 The magnetic powder plate is compressed by a pressure of , thereby forming a magnetic powder plate that is easily crushed by the pressure. At this time, the magnetic powder plate is divided into a lower magnetic powder plate for forming the lower part of the magnetic core 11 and an upper magnetic powder plate for forming the upper part of the magnetic core 11. The shape of the lower magnetic powder plate can be any shape as long as a recess for accommodating the coil element 12 is provided, and it is preferably a can shape with an E-shaped cross-sectional shape. In addition, the shape of the upper magnetic powder plate is preferably a flat plate shape in a manner to close the recess of the lower magnetic powder plate.

[0064] Next, pressure molding is performed. Fig.10 This is a diagram for explaining a part of a method for manufacturing an inductor according to an embodiment of the present invention, schematically showing a state before an upper magnetic powder plate 15a, a component formed by integrating a coil element 12 and an electrode component 13, and a lower magnetic powder plate 15b are placed in a cavity of a mold 14 and press-molded.

[0065] like Fig.10 As shown, the upper magnetic powder plate 15a is placed in the mold 14, and the component formed by integrating the coil element 12 and the electrode component 13 is placed thereon, and the lower magnetic powder plate 15b is placed thereon, and the upper punch 14a is lowered and the lower punch 14b is raised, and the pressure is increased by about 4 tons / cm 2 The pressure is applied to the coil element 12. The pressurization is completed in a state where the magnetic core 11 is formed in the cavity of the mold 14, and the bottom surface portion 13b and the supporting portion 13c of the electrode component 13 extend outward from the magnetic core 11 (the cavity of the mold 14). During the pressurization, the support portion 13c of the electrode component 13 is placed on the mold, so that the position of the coil element 12 can be positioned. Fig. 9 As shown, a gap is provided above the supporting portion 13c. This can prevent the coil element or the electrode member from being excessively stressed during press molding and causing wire breakage.

[0066] In addition, as a method of placing the lower magnetic powder plate 15b into the mold, the lower magnetic powder plate 15b may be placed after placing the component formed by integrating the coil element 12 and the electrode member 13 into the mold. Alternatively, the lower magnetic powder plate 15b may be placed into the mold 14 in a state where it is combined with the component formed by integrating the coil element 12 and the electrode member 13.

[0067] By placing the component formed by connecting and integrating the coil element 12 and the electrode component 13 into the cavity of the mold and performing powder compacting in this way, the end surface portion 13a of the electrode component 13 is compacted in the state of entering the cavity of the mold, and at least a part of the thickness is buried in the magnetic core 11 and fixed. On the other hand, the bottom surface portion 13b of the electrode component 13 is bent on the bottom surface side of the magnetic core 11 after compacting in the state of extending out of the cavity of the mold, and is therefore not fixed to the magnetic core 11. As described above, by fixing the end surface portion 13a of the electrode component 13 to the magnetic core 11, vibration resistance can be ensured, and since the bottom surface portion 13b of the electrode component 13 is not fixed to the magnetic core 11, heat cycle resistance can be improved.

[0068] In addition, Figure 2 As shown, the surface of the electrode component 13 on the end face 11a side of the magnetic core that is not provided with a plating layer is opposite to the magnetic core 11. On the other hand, the electrode component 13 on the surface opposite to the surface facing the magnetic core 11 is provided with a plating layer 13f, so it is easy to solder to the mounting substrate. In addition, the electrode component 13 on the surface facing the magnetic core 11 is not plated, so even when the temperature reaches a high temperature during solder reflow, the bonding strength between the magnetic core 11 and the electrode component 13 can be maintained.

[0069] The angle formed by the surface of the upper punch 14a forming the bottom surface 11b of the magnetic core and the surface contacting the end surface 13a of the electrode member 13 is set to approximately 86.5°, and the angle formed by the surface of the upper punch 14a forming the bottom surface 11b of the magnetic core and the two sides of the end surface 13a of the electrode member 13 is set to approximately 89.5°. In this way, the inclination of the inner wall surface of the mold 14 in the portion contacting the end surface 13a of the electrode member 13 is made different from the surface of the end surface 11a' of the magnetic core on both sides of the electrode member, so that when the magnetic core 11 is taken out after the press molding, even if the magnetic core 11 is to expand as a whole, the inner wall of the mold 14 on both sides of the end surface 13a of the electrode member 13 provides support and suppresses the expansion of the surface 11c of the end surface of the electrode member. Therefore, the electrode member 13 on the end surface 11 a side of the core can be less likely to be damaged.

[0070] Furthermore, the position of the end surface portion 13a of the electrode member 13 is determined by the die 14, so the shape is stable. Therefore, when the inductor is mounted and welded, the welding can be performed stably.

[0071] In addition, when the component formed by integrating the coil element 12 and the electrode component 13 is placed in the mold 14, it can be deformed so that the distance between the end surface portions 13a of the electrode component 13 becomes smaller and inserted, and then the distance between the end surface portions 13a of the electrode component 13 is expanded so that the end surface portions 13a of the electrode component 13 abut against the inner wall of the mold 14, and the lower magnetic powder plate 15b is placed and pressure molding is performed. In this way, when the component formed by integrating the coil element 12 and the electrode component 13 is inserted into the mold 14, the end surface portions 13a of the electrode component 13 can be prevented from rubbing against the inner wall of the mold 14, and damage can be prevented.

[0072] After the press-molded component is removed from the mold 14, the magnetic core 11 is thermally cured, the supporting portion 13c of the electrode component 13 is cut, and the bottom surface portion 13b is bent, thereby obtaining an inductor. Figure 2 As shown in FIG. 1 , a recess is provided on the bottom surface 11b of the magnetic core. The end surface portion 13a of the electrode component 13 abuts against the end surface 11a of the magnetic core, and a portion of the bottom surface portion 13b thereof is bent so as to enter the recess. A gap is formed between the bottom surface portion 13b and the recess near the bending point of the electrode component 13. The front end of the bottom surface portion 13b abuts against or is close to the recess, and the bottom surface portion 13b is not buried in the magnetic core 11.

[0073] As a summary, the inductor and the method for manufacturing the inductor according to the present embodiment will be exemplified.

[0074] [Example 1]

[0075] An inductor comprises: a magnetic core, which is pressurized by mixing magnetic material powder and an adhesive, and has a bottom surface and an end surface connected to the bottom surface; a coil element, which is buried in the magnetic core; and an electrode component, which is electrically and mechanically connected to the end of the coil element, the electrode component is bent from the end surface of the magnetic core toward the bottom surface of the magnetic core, the electrode component has a rivet portion, the end of the coil element is overlapped with the electrode component and riveted at the rivet portion, and the riveted portion is welded to be electrically and mechanically connected, the rivet portion is buried in the magnetic core, the electrode component on the end surface side of the magnetic core is fixed by being buried in the magnetic core through at least a part of the thickness, and the electrode component on the bottom surface side of the magnetic core is not fixed to the magnetic core.

[0076] [Example 2]

[0077] In the inductor described in Example 1, a notch is provided at the end of the coil element between the winding portion and the rivet portion of the coil element, the end of the coil element is bent at the notch, and the rivet portion and the notch are buried in the magnetic core.

[0078] [Example 3]

[0079] In the inductor as described in Example 1 or Example 2, the angle formed by the bottom surface of the magnetic core and the end surfaces of the magnetic core on both sides of the electrode component is larger than the angle formed by the bottom surface of the magnetic core and the surface of the electrode component arranged on the end surface side of the magnetic core, and the angle formed by the bottom surface of the magnetic core and the end surfaces of the magnetic core on both sides of the electrode component is smaller than 90.0°.

[0080] [Example 4]

[0081] In the inductor according to Example 3, an angle formed by a surface of the electrode member provided on the end surface side of the magnetic core and the end surfaces of the magnetic core on both sides of the electrode member is 2.0° or more and 5.0° or less.

[0082] [Example 5]

[0083] In the inductor described in Example 1 or Example 2, the surface of the electrode member facing the magnetic core is not provided with a plating layer, and the surface of the electrode member not facing the magnetic core is provided with a plating layer.

[0084] [Example 6]

[0085] A method for manufacturing an inductor, wherein a coil element is embedded in a magnetic core having a bottom surface and an end surface connected to the bottom surface, and the end of the coil element is electrically and mechanically connected to an electrode component, the method comprising: a step of forming a coil element by spirally winding a conductive wire with an insulation coating on the surface, leading both ends in opposite directions, and peeling off the insulation coating of the end; a step of preparing an electrode component composed of a rivet portion, an end surface portion, a bottom surface portion, and a supporting portion; a rivet step of overlapping the end of the coil element with a part of the electrode component and riveting the rivet portion to fix the end of the coil element to the electrode component; a welding step of irradiating the riveted portion with a laser to integrate the coil element with the electrode component; and a step of welding the wire The process of bending the end of the coil element or the electrode component; the process of mixing magnetic material powder with resin and molding to obtain an upper magnetic powder plate and a lower magnetic powder plate; a magnetic core forming process, after placing the upper magnetic powder plate into the mold, inserting a component formed by integrating the coil element and the electrode component, placing the lower magnetic powder plate thereon and press-molding to form the magnetic core; an electrode forming process, cutting off the supporting part of the electrode component and bending the bottom surface part to form an electrode, the rivet part is buried in the magnetic core, the electrode component on the end surface side of the magnetic core is fixed by being buried in the magnetic core through at least a part of the thickness, and the electrode component on the bottom surface side of the magnetic core is not fixed to the magnetic core.

[0086] [Example 7]

[0087] The method for manufacturing an inductor as described in Example 6 further includes a step of providing a notch portion at an end portion of the coil element between the winding portion of the coil element and the rivet portion, wherein the rivet portion and the notch portion are buried in the magnetic core.

[0088] [Example 8]

[0089] In the method for manufacturing an inductor according to Example 7, the depth of the notch is not less than 40% and not more than 70% of the thickness of the end portion of the coil element around the notch.

[0090] [Example 9]

[0091] The method for manufacturing an inductor as described in Example 7 or Example 8 includes a step of providing a notch portion at the end of the coil element at the portion to be bent, before the step of bending the end of the coil element or the electrode component, wherein the notch portion is buried in the magnetic core.

[0092] [Example 10]

[0093] In the manufacturing method of the inductor as described in Example 6 or Example 7, the portion of the inner wall of the mold that abuts the end face portion of the electrode component is made to have a different inclination from both sides thereof, so that the angle formed by the bottom surface of the magnetic core and the end faces of the magnetic core on both sides of the electrode component is set to be larger than the angle formed by the bottom surface of the magnetic core and the surface of the end face portion of the electrode component arranged on the end face side of the magnetic core, and the angle formed by the bottom surface of the magnetic core and the end faces of the magnetic core on both sides of the electrode component is set to be smaller than 90.0°.

[0094] [Example 11]

[0095] In the method for manufacturing an inductor according to Example 6 or 7, the angle formed by the surface of the electrode member provided on the end surface side of the core and the end surfaces of the core on both sides of the electrode member is set to be greater than or equal to 2.0° and less than or equal to 5.0°.

[0096] [Example 12]

[0097] In the manufacturing method of the inductor as described in Example 6 or Example 7, in the riveting step, the front end portion of the end of the coil element is riveted in a state where the front end portion protrudes beyond the portion to be riveted, and in the welding step, the riveted portion is irradiated with laser to perform welding, and the front end portion of the end of the coil element after the welding step is in a molten and solidified state.

[0098] [Example 13]

[0099] In the method for manufacturing an inductor according to Example 6 or 7, a portion of the caulking portion opposite to the front end portion of the end portion of the coil element is melted and solidified.

[0100] [Example 14]

[0101] In the method for manufacturing an inductor as described in Example 6 or Example 7, image recognition is performed on the front end portion of the end of the coil element after the riveting process and the welding process, and image recognition is performed again after the welding process to confirm that the front end portion of the end of the coil element is in a molten and solidified state.

[0102] [Example 15]

[0103] In the manufacturing method of the inductor as described in Example 6 or Example 7, in the magnetic core forming step, when inserting the component formed by integrating the coil element and the electrode component into the mold, the component is deformed and inserted in such a manner that the distance between the end face portions of the electrode component becomes smaller, and then the distance between the end face portions of the electrode component is expanded so that the end face portions of the electrode component abut against the inner wall of the mold and are press-formed.

[0104] In addition, other inductors that can be used in this embodiment are exemplified.

[0105] [Example 16]

[0106] An inductor comprises: a magnetic core, which is press-formed by mixing magnetic material powder and an adhesive, and has a bottom surface and an end surface connected to the bottom surface; a coil element, which is buried in the magnetic core; and an electrode component, which is electrically and mechanically connected to the end of the coil element, the electrode component is bent from the end surface of the magnetic core toward the bottom surface of the magnetic core, the electrode component has a rivet portion, the end of the coil element is overlapped with the electrode component and riveted at the rivet portion, and the riveted portion is welded to be electrically and mechanically connected, the rivet portion is buried in the magnetic core, the angle formed by the bottom surface of the magnetic core and the end surfaces of the magnetic core on both sides of the electrode component at the end surface of the magnetic core is set to be larger than the angle formed by the bottom surface of the magnetic core and the surface of the end surface portion of the electrode component in the electrode component arranged on the end surface side of the magnetic core, and the angle formed by the bottom surface of the magnetic core and the end surfaces of the magnetic core on both sides of the electrode component is set to be smaller than 90.0°.

[0107] [Example 17]

[0108] An inductor comprises: a magnetic core, which is press-formed by mixing magnetic material powder and a binder, and has a bottom surface and an end surface connected to the bottom surface; a coil element, which is buried in the magnetic core; and an electrode component, which is electrically and mechanically connected to the end of the coil element, the electrode component is bent from the end surface of the magnetic core toward the bottom surface of the magnetic core, the electrode component has a rivet portion, the end of the coil element is overlapped with the electrode component and riveted at the rivet portion, and the riveted portion is welded to be electrically and mechanically connected, a notch portion is provided at the end of the coil element between the winding portion of the coil element and the rivet portion, the end of the coil element is bent at the notch portion, the rivet portion and the notch portion are buried in the magnetic core, the electrode component on the end surface side of the magnetic core is fixed by being buried in the magnetic core through at least a part of the thickness, and the electrode component on the bottom surface side of the magnetic core is not fixed to the magnetic core.

[0109] Industrial Applicability

[0110] The inductor and the method for producing the inductor according to the present invention can obtain an inductor having excellent vibration resistance and heat cycle resistance, and are industrially useful.

[0111] Description of reference numerals:

[0112] 11 Magnetic core

[0113] 11a End face of the core

[0114] 11a' The end faces of the magnetic core on both sides of the electrode component

[0115] 11b bottom surface of the core

[0116] 11c The end surface of the electrode component

[0117] 12 Coil elements

[0118] 12a End of coil element

[0119] 12b Notch

[0120] 13 Electrode parts

[0121] 13a End surface

[0122] 13b Bottom part

[0123] 13c Supporting part

[0124] 13d Riveting part

[0125] 13f Plating

[0126] 14. Mould

[0127] 14a Upper punch

[0128] 14b Lower punch

[0129] 15a Magnetic powder board for the upper part

[0130] 15b Magnetic powder board for the lower part

[0131] 16 Laser irradiation position

[0132] w1, w2 width

Claims

1. An inductor comprising: A magnetic core is formed by mixing magnetic material powder and a binder and pressurized, and has a bottom surface and an end surface connected to the bottom surface; a coil element embedded in the magnetic core; and an electrode component electrically and mechanically connected to an end of the coil element, The electrode member is bent from the end surface of the magnetic core toward the bottom surface of the magnetic core, The electrode component has a rivet portion, the end of the coil element is overlapped with the electrode component and riveted at the rivet portion, and the riveted portion is welded to be electrically and mechanically connected. The rivet portion is embedded in the magnetic core, The electrode member on the end surface side of the magnetic core is fixed by being buried in the magnetic core with at least a portion of its thickness. The electrode member on the bottom surface side of the magnetic core is not fixed to the magnetic core.

2. The inductor according to claim 1, A notch portion is provided at an end of the coil element between the winding portion and the rivet portion of the coil element. The end of the coil element is bent at the notch portion, The rivet portion and the notch portion are embedded in the magnetic core.

3. The inductor according to claim 1 or 2, The angle formed by the bottom surface of the magnetic core and the end surfaces of the magnetic core on both sides of the electrode component is larger than the angle formed by the bottom surface of the magnetic core and the surface of the electrode component provided on the end surface side of the magnetic core. An angle formed by the bottom surface of the magnetic core and the end surfaces of the magnetic core on both sides of the electrode member is smaller than 90.0°.

4. The inductor according to claim 3, An angle formed between a surface of the electrode member provided on the end surface side of the magnetic core and the end surfaces of the magnetic core on both sides of the electrode member is 2.0° or more and 5.0° or less.

5. The inductor according to claim 1 or 2, No plating layer is provided on the surface of the electrode component facing the magnetic core, A plating layer is provided on a surface of the electrode member that does not face the magnetic core.

6. A method for manufacturing an inductor, wherein a coil element is embedded in a magnetic core having a bottom surface and an end surface connected to the bottom surface, and the end of the coil element is electrically and mechanically connected to an electrode component, wherein the manufacturing method include: A step of forming a coil element by spirally winding a conductive wire whose surface is covered with insulation, leading both ends in opposite directions, and then peeling off the insulation coating at the end portions; A step of preparing an electrode component including a rivet portion, an end surface portion, a bottom surface portion, and a supporting portion; a riveting step of overlapping an end portion of the coil element with a portion of the electrode component and riveting the end portion of the coil element at the riveting portion, thereby fixing the end portion of the coil element to the electrode component; A welding step of irradiating the riveted portion with a laser to integrate the coil element and the electrode component; a step of bending an end portion of the coil element or the electrode member; A step of mixing magnetic material powder with resin and molding to obtain an upper magnetic powder plate and a lower magnetic powder plate; a magnetic core forming step of inserting a component formed by integrating the coil element and the electrode component after placing the upper magnetic powder plate into a mold, placing the lower magnetic powder plate thereon, and performing pressure molding to form the magnetic core; and an electrode forming step of cutting the supporting portion of the electrode member and bending the bottom surface portion to form an electrode, The rivet portion is embedded in the magnetic core, The electrode member on the end surface side of the magnetic core is fixed by being buried in the magnetic core with at least a portion of its thickness. The electrode member on the bottom surface side of the magnetic core is not fixed to the magnetic core.

7. The method for manufacturing an inductor according to claim 6, The manufacturing method also include: a step of providing a notch portion at an end portion of the coil element between the winding portion of the coil element and the rivet portion, The rivet portion and the notch portion are embedded in the magnetic core.

8. The method for manufacturing an inductor according to claim 7, The depth of the notch portion is not less than 40% and not more than 70% of the thickness of the end portion of the coil element around the notch portion.

9. The method for manufacturing an inductor according to claim 7 or 8, Before the step of bending the end of the coil element or the electrode member, a step of providing a notch at the end of the coil element at a portion to be bent is included. The notch portion is embedded in the magnetic core.

10. The method for manufacturing an inductor according to claim 6 or 7, The portion of the inner wall of the mold that abuts against the end face portion of the electrode component is made to have a different inclination from both sides thereof, so that the angle formed by the bottom surface of the magnetic core and the end faces of the magnetic core on both sides of the electrode component is set to be larger than the angle formed by the bottom surface of the magnetic core and the surface of the end face portion of the electrode component arranged on the end face side of the magnetic core, and the angle formed by the bottom surface of the magnetic core and the end faces of the magnetic core on both sides of the electrode component is set to be smaller than 90.0°.

11. The method for manufacturing an inductor according to claim 6 or 7, The angle formed by the surface of the electrode member provided on the end surface side of the magnetic core and the end surfaces of the magnetic core on both sides of the electrode member is set to be 2.0° or more and 5.0° or less.

12. The method for manufacturing an inductor according to claim 6 or 7, In the caulking step, the caulking is performed in a state where the front end portion of the end portion of the coil element protrudes beyond the portion to be caulked. In the welding process, the riveted portion is irradiated with laser light to perform welding. After the welding step, the tip end portion of the end portion of the coil component is in a melted and solidified state.

13. The method for manufacturing an inductor according to claim 6 or 7, A portion of the caulking portion opposite to the front end portion of the end portion of the coil element is in a melted and solidified state.

14. The method for manufacturing an inductor according to claim 6 or 7, After the riveting step and the welding step, image recognition is performed on the front end of the end of the coil element. After the welding step, image recognition was performed again to confirm that the tip end portion of the end portion of the coil element was in a melted and solidified state.

15. The method for manufacturing an inductor according to claim 6 or 7, In the magnetic core forming process, when inserting the component formed by integrating the coil element and the electrode component into the mold, it is deformed and inserted in a manner such that the distance between the end face portions of the electrode component becomes smaller, and then the distance between the end face portions of the electrode component is expanded so that the end face portions of the electrode component abut against the inner wall of the mold and are press-formed.

Images