Coil arrangement

Abstract

The present application provides a coil device capable of realizing large current and miniaturization. A first end (12a) of a first wire (12) is connected to a first wiring portion (63a) of a first terminal electrode (60), a first end (14a) of a second wire (14) is connected to a second wiring portion (63b) of the first terminal electrode (60), a second end (12b) of the first wire (12) is connected to a first wiring portion (73a) of a second terminal electrode (70), and a second end (14b) of the second wire (14) is connected to a second wiring portion (73b) of the second terminal electrode (70). The first wiring portion (63a) and the second wiring portion (63b) of the first terminal electrode (60) are arranged at positions apart from each other, and the first wiring portion (73a) and the second wiring portion (73b) of the second terminal electrode (70) are arranged at positions apart from each other.

Description

Technical Field

[0001] The present invention relates to a coil device for power inductors, such as DC-DC converters. Background Technology

[0002] Inductors are made by using a coil with wire wound on a core (Patent Document 1). In the vertical coil assembly described in Patent Document 1, where the core portion is perpendicular to the mounting surface, terminal electrodes and wires can be connected by laser welding on the side of the flange portion. Therefore, compared to horizontal coil assemblies, the coil assembly of Patent Document 1 has the advantage of enabling robust and reliable wire connection.

[0003] Due to the increasing current of electronic devices in recent years, coil devices also require higher current capabilities. However, in existing coil devices, when using thick, low-resistance wires to cope with high current, the thick wire leads are not easy to bend, making wiring operations more complicated, and posing a challenge to the large size of the coil device.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-134590 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The present invention is proposed in view of the following actual situation, and its purpose is to provide a coil device that can achieve both high current and miniaturization.

[0009] Technical solutions for solving the problem

[0010] To achieve the above objectives, the coil device provided by the present invention includes:

[0011] A magnetic core having a core portion and a flange portion;

[0012] The first and second wires wound around the core portion;

[0013] The first terminal electrode and the second terminal electrode are mounted insulated from each other on the flange portion, wherein...

[0014] The first end of the first wire is connected to the first wiring portion of the first terminal electrode.

[0015] The first end of the second wire is connected to the second terminal portion of the first terminal electrode.

[0016] The second end of the first wire is connected to the first terminal part of the second terminal electrode.

[0017] The second end of the second wire is connected to the second terminal electrode of the second terminal.

[0018] The first wiring portion and the second wiring portion of the first terminal electrode are positioned at a distance from each other.

[0019] The first and second wiring portions of the second terminal electrode are positioned at a distance from each other.

[0020] In the coil device of the present invention, the current between the first terminal electrode and the second terminal electrode is shunted at least to the coil formed by the first wire and the coil formed by the second wire. Therefore, the current flowing in either the first or second wire can be reduced, while the total current flowing between the first and second terminal electrodes can be increased. Thus, a coil device capable of handling high currents can be realized even without using thick wire.

[0021] Furthermore, since thick wire is not required, the wire leads (first or second end / hereinafter the same) are easy to bend, making wiring easier and improving the reliability of the connection strength between the wire leads and the terminal electrodes at the connection point. Moreover, because thick wire is not required, there is no need to increase the thickness of the flange portion of the magnetic core, which also enables the miniaturization of the coil device.

[0022] Furthermore, because the first and second terminals of each terminal electrode are positioned separately from each other, it is easy to individually connect the lead ends of the wires at each terminal terminal to the terminal electrode using methods such as laser welding. In addition, the heat generated during the connection process at any one terminal terminal is less likely to adversely affect other terminals, thus improving the reliability of the connections.

[0023] Preferably, the first and second wiring portions of the first terminal electrode are arranged on opposite sides of each other along one side of the flange. More preferably, the first and second wiring portions of the second terminal electrode are arranged on opposite sides of each other along the other side of the flange.

[0024] By adopting this structure, the first and second terminals of each terminal electrode can be easily positioned separately. Therefore, it becomes easier to individually connect the lead ends of the wires at each terminal to the terminal electrode using methods such as laser welding. Furthermore, the heat generated during the connection process at one terminal is less likely to adversely affect other terminals, thus improving the reliability of these connections. Additionally, because the terminals are located on the side of the flange, rather than on the outer end face of the flange which serves as the mounting surface, a lower height for the coil assembly can also be achieved.

[0025] Preferably, the first wiring portion of the first terminal electrode and the first wiring portion of the second terminal electrode are arranged diagonally across the core portion. More preferably, the second wiring portions of the first terminal electrode and the second wiring portions of the second terminal electrode are arranged diagonally across the core portion.

[0026] By adopting this structure, it is easy to make the length from the first terminal portion connected to the first end of the first wire to the first terminal portion connected to the second end of the first wire approximately the same as the corresponding length of the second wire. The corresponding length of the second wire refers to the length from the second terminal portion connected to the first end of the second wire to the second terminal portion connected to the second end of the second wire. By making their lengths approximately the same, it is easy to make the current flowing in the coil formed by the first wire and the current flowing in the coil formed by the second wire approximately the same. Therefore, it is easy to maximize the current flowing in the coil assembly.

[0027] Preferably, the first terminal electrode has a first mounting piece mounted on the outer end face of the flange portion. More preferably, the second terminal electrode has a second mounting piece mounted on the outer end face of the flange portion. By mounting these mounting pieces to the outer end face of the magnetic core using an adhesive or the like, the first and second terminal electrodes can be easily mounted on the flange portion.

[0028] Preferably, the first terminal electrode further includes a wiring stand for forming the first wiring portion and the second wiring portion, the wiring stand for forming the first wiring portion and the second wiring portion respectively, the wiring stand for forming the first wiring portion and the second wiring portion respectively, the wiring stand for forming the first wiring portion and the second wiring portion respectively, the wiring stand for forming the first wiring portion and the second wiring portion respectively, the wiring stand for forming the first wiring portion and the second wiring portion respectively, the wiring stand for forming the second wiring portion and the second wiring portion respectively, the second wiring stand for forming the first wiring portion and the second wiring portion respectively, the second ...

[0029] Alternatively, a retaining piece can be provided on the wiring stand to hold and temporarily fix the lead end of the wire. By bringing the lead end of the wire into contact with the wiring stand and performing laser welding, a wiring section is formed.

[0030] Preferably, a notch is formed on the side of the flange where the wiring stand is formed. By inserting the wiring stand into the notch, the wiring portion is housed within the notch, preventing it from protruding outwards from the flange. As a result, this facilitates miniaturization of the coil assembly, reduces the likelihood of the wiring portion colliding with other components, and improves the reliability of the wiring connection.

[0031] Preferably, a recess is formed on the outer end face of the flange, and the first terminal electrode or the second terminal electrode has an inner stand-up tab that loosely enters the recess.

[0032] By adopting such a structure, when the coil device is installed on the circuit board, the connecting parts such as solder also enter the interior of the recess, and a fillet is also formed on the outer surface of the inner upright piece, thereby improving the bonding strength between the circuit board and the terminal electrode.

[0033] The terminal electrodes are, for example, made of metal terminals, and the mounting tabs, which are the main components, can be bonded to the outer end face of the flange. Furthermore, the inner stand-up tabs of the terminal electrodes only loosely enter the recess, and do not engage with the wall of the recess. Therefore, even if the coil assembly is exposed to harsh temperature variations, such as -40 to 150°C, the thermal stress acting on the terminal electrodes is less likely to affect the flange of the magnetic core, reducing the possibility of cracks in the magnetic core. Additionally, even under harsh temperature conditions, the bonding strength between the coil assembly and the circuit board deteriorates less.

[0034] Preferably, a predetermined gap is formed between the sidewall of the recess connected to the bottom wall and the front end of the inner upright piece entering the recess. With this structure, even when the coil assembly is exposed to harsh temperature variations, the thermal stress acting on the terminal electrodes is less likely to affect the flange of the magnetic core, reducing the possibility of cracks in the magnetic core. Furthermore, even under harsh temperature conditions, the degradation of the bonding strength between the coil assembly and the circuit board is minimal.

[0035] Preferably, the first terminal electrode or the second terminal electrode further has an outer raised piece that rises from the end edge of the first mounting piece or the second mounting piece toward the side of the flange. This facilitates the formation of rounded corners for solder or other connecting components on the outer surface of the outer raised piece. Therefore, the bonding strength between the terminal electrode and the circuit board is further improved.

[0036] The first mounting plate or the second mounting plate may also have a pair of separate mounting plates that are respectively connected to the first wiring portion and the second wiring portion, and these separate mounting plates may also be connected by the outer upright plate. Additionally, the first wiring portion and the second wiring portion of the first terminal electrode or the second terminal electrode may also be connected by the first mounting plate or the second mounting plate. Attached Figure Description

[0037] Figure 1A This is a perspective view of a coil device according to an embodiment of the present invention.

[0038] Figure 1B yes Figure 1A The front view of the coil assembly shown.

[0039] Figure 1C yes Figure 1A The right-side view of the coil assembly shown (the left-side view is symmetrical to the right-side view).

[0040] Figure 1D yes Figure 1A A top view of the coil assembly shown.

[0041] Figure 1E From Figure 1A A perspective view of the coil device as seen from the bottom side.

[0042] Figure 2A It is along Figure 1A The schematic cross-sectional view of the IIA-IIA line is shown.

[0043] Figure 2B It is along Figure 1A The diagram shown is a schematic cross-sectional view of the IIB-IIB line, omitting the coil section and the outer resin.

[0044] Figure 3A It is Figure 1A The diagram shows a three-dimensional representation of the drum-shaped core and terminal electrodes disassembled.

[0045] Figure 3B This is a perspective view showing the drum-shaped core and terminal electrodes of another embodiment of the invention of this application in an exploded view.

[0046] Figure 4 yes Figure 2A The diagram shown is a three-dimensional view of only the coil section.

[0047] Figure 5A yes Figure 1E The image shown is a three-dimensional view of the drum-shaped core viewed from the bottom side.

[0048] Figure 5B This is a perspective view of the drum-shaped core used in a coil device according to another embodiment of the present invention, viewed from the bottom side.

[0049] Figure 5C This is a perspective view of the drum-shaped core used in a coil device according to another embodiment of the present invention, viewed from the bottom side. Detailed Implementation

[0050] The present invention will now be described based on the embodiments shown in the accompanying drawings.

[0051] Will Figures 1A to 1E The coil device 2 shown in one embodiment of the present invention is used as a component, for example, a DC-DC converter, and is particularly preferred as a power inductor.

[0052] The coil device 2 has a drum-shaped core 20 that serves as the magnetic core. Examples of magnetic materials constituting the drum-shaped core 20 include soft magnetic materials such as metals and ferrite, but there are no particular limitations. Figure 2A As shown, the drum-shaped core 20 has a core portion 30 in which two wires (first wire 12 and second wire 14) constituting the coil portion 10 are wound along the spool direction of the core 20.

[0053] The core portion 30 around the wound wires 12 and 14 is preferably covered by an outer resin 15. Covering it with the outer resin 15 effectively protects the coil portion 10 and also suppresses short circuits. Alternatively, the outer resin 15 can be made of a magnetic resin. With this structure, the magnetic resin 15 becomes a pathway for the magnetic field, improving the magnetic properties of the coil assembly 2. There are no particular limitations on the magnetic material contained in the outer resin 15; examples include magnetic powders similar to the magnetic powder constituting the core 20 or other magnetic powders.

[0054] There are no particular restrictions on wires 12 and 14; conductive core wires such as flat wires, round wires, stranded wires, Litz wires, and braided wires made of copper or similar materials, or wires with insulating covers on these conductive core wires, can be used. Specifically, known winding wires such as AIW (polyimide wire), UEW (polyurethane wire), and USTC can be used. The wire diameter of wires 12 and 14 is not particularly limited, for example, 0.1 to 0.5 mm. The wire diameter and material of the two wires 12 and 14 can also be different, but it is preferable that they are the same.

[0055] A first flange portion 40 and a second flange portion 50 are integrally formed at both ends of the core portion 30 in the winding direction (Z-axis direction). These first flange portions 40 and second flange portions 50 protrude relative to the core portion 30 toward the X-Y axis plane. Furthermore, the X-axis, Y-axis and Z-axis are perpendicular to each other, and the Z-axis is aligned with the axis of the winding spool.

[0056] The cross-section (cross-section of the X-Y axis plane) of the core portion 30 is not particularly limited, and can be a square cross-section, a rectangular cross-section, a circular cross-section, or other cross-sectional shapes, but in this embodiment, it is approximately circular.

[0057] like Figure 2A As shown, the second flange portion 50 has an outer end face 52 in the axial direction (Z-axis direction) and an inner surface 53 in the axial direction on the opposite side. The upper end of the coil portion 10 in the Z-axis direction is located on the inner surface 53. Additionally, the first flange portion 40 has an outer end face 42 in the axial direction and an inner surface 43 in the axial direction on the opposite side. The lower end of the coil portion 10 in the Z-axis direction is located on the inner surface 43 in the axial direction. Furthermore, there are no particular limitations on the number of winding layers of wires 12 and 14, nor on the winding method of wires 12 and 14.

[0058] The specific shape of the second flange portion 50 is not particularly limited. In this embodiment, for example... Figure 1D As shown, the second flange 50 has side surfaces 50a, 50a facing each other in the Y-axis direction and side surfaces 50b, 50b facing each other in the X-axis direction, and has an overall quadrilateral shape when viewed from the Z-axis direction. Furthermore, chamfered portions 54 are formed at the four corners where the virtual extended surfaces of the side surfaces 50a, 50a and the virtual extended surfaces of the side surfaces 50b, 50b intersect. The chamfered portions 54... Figure 3A The drum-shaped core 20 shown is integrally formed together with the first flange portion 40, the second flange portion 50 and the core portion 30 during molding, but it can also be formed by cutting or grinding after integral molding.

[0059] Furthermore, the specific shape of the first flange portion 40 is not particularly limited; in this embodiment, for example... Figure 5A As shown, the device has side surfaces 40a, 40a facing each other in the Y-axis direction and side surfaces 40b, 40b facing each other in the X-axis direction, and has an overall quadrilateral shape when viewed from the Z-axis direction. Furthermore, notches 44 are formed at the four corners where the virtual extended surfaces of the side surfaces 40a, 40a and the virtual extended surfaces of the side surfaces 40b, 40b intersect. The notches 44 are integrally formed with the first flange 40, the second flange 50, and the core portion 30 during the forming of the drum-shaped core 20, but they can also be formed after integral forming by machining or grinding.

[0060] In this embodiment, as well as Figure 5A As shown, the side surfaces 40a and 40a of the first flange portion 40 are located on the same virtual plane (X-Z plane) in a manner that is substantially flush with the side surfaces 50a and 50a of the second flange portion 50. Furthermore, the side surfaces 40b and 40b of the first flange portion 40 are located on the same virtual plane (Y-Z plane) in a manner that is substantially flush with the side surfaces 50b and 50b of the second flange portion 50.

[0061] Furthermore, in this embodiment, the dimensions of each notch 44 in the first flange portion 40 are larger than the dimensions of each chamfer portion 54 in the second flange portion 50, such as... Figure 1D As shown, when viewing the outer end face 52 of the second flange portion 50 from above the Z-axis, the outline of the first flange portion 40 located below the Z-axis is not visible. However, the portion of the second flange portion 50 corresponding to the chamfered portion 54 is visible. Figure 1A Part of the wiring sections 63 and 73 shown.

[0062] That is, in this embodiment, the outer dimensions of the second flange portion 50 are approximately the same as those of the first flange portion 40. However, because the first flange portion 40 has a notch 44 that is larger than the chamfered portion 54, their volumes are different if they are of the same thickness. In order to make the volume of the second flange portion 50 approximately the same as that of the first flange portion 40, the Z-axis thickness of the first flange portion 40 can also be made larger than the Z-axis thickness of the second flange portion 50.

[0063] like Figure 5A As shown, on the outer end face 42 of the first flange 40, four independent recesses 46 are arranged at predetermined intervals in both the X-axis and Y-axis directions, positioned as close as possible to the center of the outer end face 42. Each independent recess 46 is formed to be longer along the Y-axis direction, and the spacing between adjacent independent recesses 46 along the X-axis or Y-axis is set to ensure... Figure 3A The insulation dimensions of adjacent terminal electrodes (first terminal electrode 60 and second terminal electrode 70) along the X-axis are shown.

[0064] In this embodiment, such as Figure 3A As shown, a pair of terminal electrodes 60 and 70 are mounted on the outer end face 42 in the spool direction of the first flange portion 40. The terminal electrodes 60 and 70 are made of conductive metal plates such as tough steel, phosphor bronze, brass, iron, and nickel, the details of which will be described later.

[0065] Terminal electrode 60 and terminal electrode 70 each have plate-shaped mounting plates 61 and 71, which have planes substantially parallel to the planes containing the X and Y axes. Figure 1E As shown, these mounting pieces 61 and 71 are bonded to the outer end face 42 of the first flange portion 40 in the spool direction using adhesive or the like. Alternatively, terminal mounting grooves matching the shape of the mounting pieces 61 and 71 may be formed on the outer end face 42 of the first flange portion 40 to which the mounting pieces are bonded.

[0066] The depth of the terminal mounting groove is preferably smaller than the thickness of each mounting piece, and the bottom surface of the mounting pieces 61 and 71 preferably protrudes beyond the outer end face 42 in the spool direction. Thus, the mounting portions 61 and 71 of the coil assembly 2 are connected to the coil assembly 2 by connecting components such as solder 84. Figure 2B The installation operation becomes easier when the wiring pattern 82 of the circuit board 80, etc., is shown.

[0067] like Figure 3A As shown, at both ends of the mounting plate 61 in the Y-axis direction, near the outer side in the X-axis direction, a first wiring stand-up piece 62a and a second wiring stand-up piece 62b are integrally formed in a manner that allows them to stand upright in the Z-axis direction. Similarly, at both ends of the mounting plate 71 in the Y-axis direction, near the outer side in the X-axis direction, a first wiring stand-up piece 72a and a second wiring stand-up piece 72b are integrally formed in a manner that allows them to stand upright in the Z-axis direction.

[0068] The first wiring stand-up piece 62a and the first wiring stand-up piece 72a are disposed diagonally across the core portion 30 of the first flange portion 40. Similarly, the second wiring stand-up piece 62b and the second wiring stand-up piece 72b are also disposed diagonally across the core portion 30 of the first flange portion 40.

[0069] These connectors, using stand-up tabs 62a, 62b, 72a, and 72b, can respectively contact the notch side surface 40c of each notch 44 in the first flange portion 40. The notch side surface 40c is a surface that retracts from the side surface 40a into the inside of the notch 44 along the Y-axis and is a surface that is approximately parallel to the side surface 40a.

[0070] The front ends of each of the wiring support pieces 62a, 62b, 72a, and 72b are bent back to form retaining pieces 62a1, 62b1, 72a1, and 72b1, respectively. A retaining piece 62a1 is clamped between the wiring support piece 62a and the wiring support piece 62a. Figure 4 The first lead portion (first end) 12a of the first wire 12 shown is joined together to form Figure 1A The first wiring portion 63a is shown. In the first wiring portion 63a, the first lead portion 12a and the stand-up piece 62a of the first terminal electrode 60 are electrically connected.

[0071] In addition, Figure 3A The retaining piece 62b1 shown is clamped between the wiring stand piece 62b and the wiring stand piece 62b. Figure 4 The first lead portion (first end) 14a of the second wire 14 shown forms Figure 1D The second wiring section 63b is shown. In the second wiring section 63b, the first lead section 14a and the stand-up piece 62b of the first terminal electrode 60 are electrically connected.

[0072] In addition, Figure 3A The retaining piece 72a1 shown is clamped between the wiring stand piece 72a and the wiring stand piece 72a. Figure 4 The second lead portion (second end) 12b of the first wire 12 shown forms Figure 1D The first wiring portion 73a is shown. The second lead portion 12b and the stand-up piece 72a of the second terminal electrode 70 are electrically connected in the first wiring portion 73a.

[0073] Moreover, in Figure 3A The retaining piece 72b1 shown is clamped between the wiring stand piece 72b and the wiring stand piece 72b. Figure 4 The second lead portion (second end) 14b of the second line 14 shown forms Figure 1D The second wiring portion 73b is shown. In the second wiring portion 73b, the second lead portion 12b and the stand-up piece 72b of the second terminal electrode 70 are electrically connected.

[0074] Each of the wiring portions 63a, 63b, 73a, and 73b is preferably formed by laser welding. For example, a laser used for welding is used to irradiate from below the flange portion 40 along the Z-axis, and the front ends of the lead portions 12a, 12b, 14a, and 14b are laser welded to the wiring stand-up pieces 62a, 62b, 72a, and 72b, respectively, to form the wiring portions 63a, 63b, 73a, and 73b.

[0075] Installed respectively Figure 4 The wiring support pieces 62a, 62b, 72a, and 72b of the lead portions 12a, 12b, 14a, and 14b shown are arranged in... Figure 5A The interior of each notch 44 of the first flange portion 40 shown. Furthermore, as... Figure 1D As shown, a portion of the wiring support pieces 62a, 62b, 72a, and 72b, which have wiring portions 63a, 63b, 73a, and 73b, are disposed on the outer side of the chamfered portion 54k of the second flange portion 50. Therefore, a laser irradiating from below the flange portion 40 along the Z-axis can form wiring portions 63a, 63b, 73a, and 73b without irradiating any one of the flange portions 40 or 50.

[0076] like Figure 3A As shown, at the outer ends of the mounting portions 61 and 71 in the X-axis direction, a pair of outer lifting plates 64a and 64b and a pair of outer lifting plates 74a and 74b are integrally formed in a manner that allows them to stand upright in the Z-axis direction. The standing height of each outer lifting plate 64a, 64b, 74a, and 74b is the same as the standing height of the wiring lifting plates 62a, 62b, 72a, and 72b.

[0077] Furthermore, at the inner ends of the mounting portions 61 and 71 in the X-axis direction, a pair of inner upright pieces 66a and 66b and a pair of inner upright pieces 76a and 76b are integrally formed in a manner that allows them to stand upright in the Z-axis direction. The upright height of the inner upright pieces 66a, 66b, 77a, and 77b is smaller than the upright height of the outer upright pieces 64a, 64b, 74a, and 74b.

[0078] Furthermore, the elevation angle of the outer support plates 64a, 64b, 74a, 74b relative to the mounting portions 61, 71 is preferably approximately 90 degrees, the same as that of the wiring support plates 62a, 62b, 72a, 72b. However, the elevation angle of the inner support plates 66a, 66b, 77a, 77b is preferably greater than 90 degrees. Figure 2B As shown, the preferred temperature is 95–160 degrees Celsius, and more preferably 100–150 degrees Celsius.

[0079] like Figure 2BAs shown, the outer raised pieces 64b and 74a (and 64a and 74b as well) preferably contact the side surface 40b of the first flange portion 40 respectively, and position each terminal electrode 60 in the X-axis direction relative to the outer end face 42 of the first flange portion 40. Additionally, as... Figure 1E As shown, the wiring stand-up tabs 62a, 62b, 72a, and 72b preferably contact the inside of the notch 44 of the first flange portion 40 and the side surface 40c of the notch. The purpose is to position each terminal electrode 60 and 70 in the Y-axis direction relative to the outer end face 42 of the first flange portion 40.

[0080] like Figure 2B As shown, each inner upright piece 66a, 66b, 77a, 77b loosely enters the interior of each individual recess 46 formed on the outer end face of the first flange portion 40. That is, each inner upright piece 66a, 66b, 77a, 77b is preferably separated from the inner wall surface of each individual recess 46 along the X-axis by a predetermined interval (predetermined gap) t1, and is also preferably separated from the outer wall surface of the individual recess 46 by a predetermined interval (predetermined gap) t2. Furthermore, it is also preferable that the front ends of each inner upright piece 66, 76 do not contact the bottom wall surface of each individual recess 46.

[0081] While there are no specific restrictions, the specified interval t1 is preferably about 1.5 to 5 times the thickness of each inner upright piece 66, 76. Furthermore, the specified interval t2 is preferably about 0.1 to 3 times the thickness of each inner upright piece 66, 76. Figure 5A The width ratio of each individual recess 46 in the Y-axis direction shown Figure 3A The inner upright pieces 66a, 66b, 77a, and 77b shown have a large width in the Y-axis direction, preferably about 1.1 to 1.5 times the width of the inner upright pieces.

[0082] Furthermore, in this application specification, "outer side" refers to the side located away from the center of the coil device 2, and "inner side" refers to the side closer to the center of the coil device 2.

[0083] Next, for Figures 1A to 5A The manufacturing method of the coil device 2 shown will be explained. First, make... Figure 3A and Figure 5A The drum-shaped core 20 shown is formed. There are no particular limitations on the forming method of the drum-shaped core 20; compression molding, CIM (ceramic injection molding), MIM (metal injection molding), etc., can be considered. After forming, it is fired to become a sintered body.

[0084] Next, terminal electrodes 60 and 70 are mounted on the outer end face 42 of the first flange portion 40 of the drum-shaped core 20. When mounting and fixing the terminal electrodes 60 and 70 to the outer end face 42, adhesive is only present between the mounting pieces 61 and 71 and the outer end face 42. Furthermore, it is preferable that the adhesive does not enter the interior of each individual recess 46, and that it does not protrude onto the outer sides 40a, 40b, and 40c of the first flange portion 40.

[0085] Furthermore, each terminal electrode 60, 70 can be easily formed by stamping and bending a metal plate (e.g., a copper plate). After the terminal electrodes 60, 70 are mounted on the drum-shaped core, or before them, they are wound around the core portion 30 of the drum-shaped core 20 shown in FIG. 5. Figure 4 The coil portion 10 is formed by the lines 12 and 14 shown. When the lines 12 and 14 are wound into the core portion 30, the lines 12 and 14 can be wound separately, or the lines 12 and 14 can be wound simultaneously in the same direction.

[0086] With the coil portion 10 formed in the core portion 30, the two ends of each of the wires 12 (14) constituting the coil portion 10, namely the lead portions 12a, 12b (14a, 14b), are located and temporarily fixed between the wiring support pieces 62a, 72a (62b, 72b) and the retaining pieces 62a1, 72a1 (62b1, 72b1) of the terminal electrode 60. Laser welding is performed in this state.

[0087] As described above, the laser irradiating from below the flange 40 along the Z-axis can form the wiring portions 63a, 63b, 73a, and 73b without irradiating any of the flange portions 40 or 50. Furthermore, as in laser welding (temperatures above 1000°C), the connection between the lead portions 12a and 12b (14a, 14b) of the winding wire 12 (14) and the terminal electrode 60 (70) is performed at a temperature higher than the temperature used to form the solder pad (230–280°C). Therefore, a robust and reliable wiring process for the wire 12 (14) can be achieved.

[0088] In the coil device 2 of this embodiment, as Figure 1E As shown, two terminal electrodes 60 and 70 are mounted on the outer end face 42 of the first flange portion 40 of the drum-shaped core 20, which serves as the magnetic core. Therefore, in this embodiment, the winding core portion 30 of the coil device 2 winds at least two wires 12 and 14, and the lead portions 12a and 12b at both ends of the wire 12 are connected to the two terminal electrodes 60 and 70, respectively. In addition, the lead portions 14a and 14b at both ends of the wire 14 are connected to the two terminal electrodes 60 and 70, respectively.

[0089] Therefore, in the coil device 2 of this embodiment, the current between the first terminal electrode 60 and the second terminal electrode 70 is shunted at least to the coil formed by the first wire 12 and the coil formed by the second wire 14. Thus, the current flowing in either the first wire 12 or the second wire 14 can be reduced, while the total current flowing between the first terminal electrode 60 and the second terminal electrode 70 can be increased. Therefore, even without using thick wire, a coil device 2 capable of handling large currents can be realized.

[0090] Furthermore, since thick wire is not required, the lead portions 12a, 12b, 14a, and 14b of wires 12 and 14 are easier to bend, simplifying wiring operations and improving the reliability of the connection strength between wires 12 and 14 and terminal electrodes 60 and 70 at the connection points. Moreover, because thick wire is not required, there is no need to increase the thickness of the flange portions 40 and 50 of the magnetic core 20 accordingly, enabling miniaturization of the coil device 2.

[0091] Furthermore, because the first wiring portions 63a, 73a and the second wiring portions 63b, 73b of each terminal electrode 60, 70 are positioned separately from each other, it is easier to connect the wires 12, 14 at each wiring portion 63a, 63b, 73a, 73b to the terminal electrodes 60, 70 individually by means of, for example, laser welding. In addition, the heat generated during the connection process at any one wiring portion 63a, 63b, 73a, 73b is less likely to adversely affect other wiring portions, thus improving the connection reliability of these wiring portions 63a, 63b, 73a, 73b.

[0092] Furthermore, in the coil device 2 of this embodiment, four independent recesses 46 are formed on the outer end face 42 of the first flange portion 40 of the drum-shaped core 20, and the inner side support plates 66a, 66b, 76a, and 76b of each terminal electrode 60 and 70 loosely enter each recess 46. Therefore, as Figure 2B As shown, when the coil device 2 is installed on the circuit board 80, the solder 84 and other connecting parts also enter the interior of the recess 46, and the outer surfaces of the inner upright pieces 66 and 76 are also rounded, thus improving the bonding strength between the wiring pattern 82 of the circuit board 80 and the terminal electrodes 60 and 70.

[0093] The terminal electrodes 60 and 70 are, for example, made of metal terminals, and the mounting portions 61 and 71, which are the main parts of them, are joined to the outer end face 42 of the flange portion 40. Furthermore, the inner stand-up tabs 66a, 66b, 76a, and 76b of each terminal electrode 60 and 70 loosely enter the recess 46, and the wall surface of the recess 46 and the inner stand-up tabs 66 and 76 do not fit together. Therefore, even if the coil device 2 is exposed to a harsh temperature environment, such as -40 to 150°C, the thermal stress acting on the terminal electrodes 60 is less likely to act on the flange portion 40 of the drum-shaped core 20, and the possibility of cracks in the drum-shaped core 20 is small. In addition, even under harsh temperature environments, the degradation of the bonding strength between the coil device 2 and the circuit board 80 is minimal.

[0094] Furthermore, in this embodiment, outer erecting pieces 64a, 64b, 74a, and 74b are integrally formed on the end edges of the mounting portions 61 and 71 located on the side opposite to the inner erecting pieces 66a, 66b, 76a, and 76b along the X-axis. The outer erecting pieces 64a, 64b, 74a, and 74b are integrally erected along the side surface 40b of the flange portion 40. For example... Figure 2B As shown, solder joints such as solder 84 can be easily formed on the outer surfaces of the stand-up pieces 66b and 76a (and the same applies to 66a and 76b). Therefore, the bonding strength between the terminal electrodes 60 and 70 and the circuit board 80 is further improved.

[0095] In addition, when the coil device 2 is mounted on, for example, the circuit board 80, the solder 84 attached to the lower surface of each terminal 60 is also attached to the outer surface of the outer support pieces 64b and 74a (64a and 74b are the same). When viewed from above in the Z-axis direction, it is not hidden by the second flange portion 50, and the attachment of the solder 84 can be confirmed.

[0096] Furthermore, in this embodiment, the standing height of the outer supporting plates 64b and 74a (and the same applies to 64a and 74b) is lower than the thickness of the first flange portion 40 in the winding direction. By adopting this structure, the coil device 2 can be made more compact. Additionally, Figure 1B The outer resin 15 shown is unlikely to adhere to the outer support plates 64a and 74b (64b and 74a are the same), and does not hinder the formation of solder pads during installation.

[0097] In addition, such as Figure 1E As shown, in this embodiment, when viewed from the X-axis direction, the inner upright pieces 66a, 66b, 76a, and 76b are located at the core portion 30 (see reference). Figure 2BThe inner uprights 66a, 66b, 76a, and 76b are positioned offset from the outer uprights 64 and 74, respectively, near the central axis of the flange portion 30. This arrangement of the inner uprights 66a, 66b, 76a, and 76b allows the recess 46 formed on the outer end face 42 of the flange portion 40 to be positioned closer to the center of the outer end face 42. As a result, the position of the recess 46 and its position relative to the core portion 30 (see reference 30) are... Figure 2B The corresponding position corresponds to the fact that even if a recess 46 is formed in the flange portion 40, the possibility of reducing the strength of the drum-shaped core 20 is small. The recess 46 can be formed without increasing the thickness of the flange portion 40, which also helps to make the coil device 2 more compact.

[0098] Moreover, in this embodiment, such as Figure 3A As shown, mounting portions 61 and 71 are integrally formed with wiring support pieces 62a, 62b, 72a, and 72b, which are different from the inner and outer support pieces. Furthermore, each wiring support piece 62a, 62b, 72a, and 72b is integrally erected along a notch side 40c parallel to the side side 40a of the flange portion 40. Wiring lead portions 12a and 14a are connected to each wiring support piece 62a and 62b, respectively, and wiring lead portions 12b and 14b are connected to each wiring support piece 72a and 72b, respectively.

[0099] By adopting this structure, each terminal electrode 60, 70 has six upright tabs 62a, 62b, 64a, 64b, 66a, 66b (or 72a, 72b, 74a, 74b, 76a, 76b), which rise from the mounting portions 61, 71 at different positions on the sides 40b, 40c or in the recesses 46 of the flange portion 40, such as... Figure 2B As shown, the solder joints of the solder 84 to the circuit board 80 are increased, and the connection strength with the circuit board 80 is further improved.

[0100] Furthermore, in this embodiment, the flange portion 40 extends radially outward from the core portion 30, and when viewed from the Z-axis direction, it has a generally quadrilateral shape. At the four corners of the flange portion 40, notches 44 are formed for connecting portions of the wiring support pieces 62a (or 62b, 72a, 72b) and the lead portions 12a (or 12b, 14a, 14b). By adopting this structure, the volume of the drum-shaped core 20 can be maintained to the maximum extent without changing the outer diameter of the flange portions 40 and 50 (maintaining the miniaturization of the coil device 2), thus suppressing the reduction of inductance.

[0101] That is, in this embodiment, it includes Figure 3AMost of the wiring support pieces 62a, 62b, 72a, and 72b for the terminal electrodes 60 and 70 shown in the wiring portions 63a, 63b, 73a, and 73b are respectively housed inside the notches 44 of the first flange portion 40. Furthermore, as shown... Figure 1D As shown, when viewing the outer end face 52 of the second flange portion 50 from above the Z-axis, only the portion corresponding to the chamfered portion 54 of the second flange portion 50 is observed. Figure 1A The wiring portions 63a, 63b, 73a, and 73b shown are partial examples. Therefore, the coil device 2 can be miniaturized, while the volume of the magnetic body of the drum-shaped core 20, including the flange portions 40 and 50, can be increased to the maximum extent. Therefore, it is also easy to improve the inductance characteristics, etc., of the coil device 2.

[0102] Furthermore, in this embodiment, the size of the flange portions 40 and 50 can be maintained without reducing inductance, and the protrusion of the terminal electrodes 60 and 70 relative to the second flange portion 50 is set to the required minimum. During the transport of the coil device 2, the possibility of collision between the terminal metal parts 60 or the wiring portions 63a, 63b, 73a, 73b and the mounting device is small.

[0103] Furthermore, in this embodiment, the adhesive used to bond the mounting portions 61 and 71 to the outer end face 42 of the flange portion 40 does not enter the recess 46. That is, the terminal electrode 60 is bonded to the outer end face 42 of the flange portion 40 only through the mounting portions 61 and 71. By adopting such a structure, even if the coil device 2 is exposed to a harsh temperature environment, the thermal stress acting on the terminal electrodes 60 and 70 is less likely to act on the flange portion 40 of the drum-shaped core 20, and the possibility of cracks or the like in the drum-shaped core 20 is small. In addition, even under harsh temperature environments, the degradation of the bonding strength between the coil device and the circuit board is small.

[0104] In addition, in this embodiment, such as Figure 2B As shown, a gap of predetermined intervals t1 and t2 is formed between the side wall of the recess 46 connected to the bottom wall and the front ends of the inner upright pieces 66 and 76 entering the recess 46. By adopting this structure, even if the coil device 2 is exposed to a harsh temperature environment, the thermal stress acting on the terminal electrode 60 is less likely to act on the flange portion 40 of the drum-shaped core 20, reducing the possibility of cracks in the drum-shaped core 20. Furthermore, even under harsh temperature conditions, the degradation of the bonding strength between the coil device 20 and the circuit board 80 is minimal.

[0105] Furthermore, the recess includes four independent recesses 46 formed on the outer end face 42 of the flange portion 40. By forming the recess on the outer end face 42 of the flange portion 40 with four independent recesses 46, the volume and strength of the drum-shaped core 20 are reduced, and the characteristics of the coil device 2 can be improved and made more compact at the same time. In addition, by adopting such a structure, it is easy to ensure the insulation between the terminal electrodes 60 and 70.

[0106] Moreover, in this embodiment, such as Figure 3A As shown, the first wiring portion 63a and the second wiring portion 63b of the first terminal electrode 60 are arranged opposite each other on one side of the side surface 40b of the flange portion 40 along the Y-axis. Similarly, the first wiring portion 72a and the second wiring portion 72b of the second terminal electrode 70 are arranged opposite each other on the other side of the side surface 40b of the flange portion 40 along the Y-axis.

[0107] By adopting this structure, the first wiring portions 63a, 73a and the second wiring portions 63b, 73b of each terminal electrode 60, 70 can be easily positioned separately from each other. Therefore, the wiring portions 63a, 63b, 73a, 73b can be separated by means such as laser welding. Figure 4 The lead portions 12a, 12b, 14a, 14b of lines 12 and 14 shown are... Figure 3A The operation of individually connecting the terminal electrodes 60 and 70 shown becomes easier. Furthermore, the heat generated during connection operations at any one of the wiring portions 63a, 63b, 73a, 73b is less likely to adversely affect other wiring portions, thus improving the connection reliability of these wiring portions. Additionally, because the wiring portions 63a, 63b, 73a, 73b are located on the side surface 40c of the flange portion, and not on the outer end face of the flange portion which serves as the mounting surface, a lower height for the coil device 2 can also be achieved.

[0108] Moreover, in this embodiment, such as Figure 3A As shown, the first wiring portion 63a of the first terminal electrode 60 and the first wiring portion 73a of the second terminal electrode 70 are arranged diagonally across the central axis of the core portion 30. Similarly, the second wiring portions 63b of the first terminal electrode 60 and the second wiring portions 73b of the second terminal electrode 70 are also arranged diagonally across the central axis of the core portion 30.

[0109] By adopting such a structure, it is easy to make from Figure 4 The first lead portion 12a of the first wire 12 shown is connected to Figure 3AThe length of the first terminal portion 73a of the second terminal electrode 70, which connects to the first terminal electrode 60's first terminal portion 63a to the second lead portion 12b of the first wire 12, is approximately the same as the corresponding length of the second wire 14. The corresponding length of the second wire 14 refers to the length from the first lead portion 14a of the second wire 14 to the second terminal portion 73b of the second terminal electrode 60, which connects to the second lead portion 14b of the second wire 14. By making their lengths approximately the same, it is easy to ensure that the current flowing in the coil formed by the first wire 14 and the current flowing in the coil formed by the second wire 14 are approximately the same. Therefore, it is easy to maximize the current flowing in the coil device 2.

[0110] Furthermore, in this embodiment, such as Figure 3B As shown, the first mounting piece 61 may also have a pair of separate mounting pieces 61a, 61b that are respectively connected to the first wiring portion 63a and the second wiring portion 63b. The separate mounting pieces 61a, 61b are separated by a notch 68 formed along the X-axis at the center of the Y-axis direction of the mounting piece 61. These separate mounting pieces 61a, 61b are connected (mechanical and electrical connection) by a single outer support piece 64 extending in the Y-axis direction.

[0111] Similarly, the second mounting plate 71 may also have a pair of separate mounting plates 71a, 71b that are respectively connected to the first wiring portion 73a and the second wiring portion 73b. The separate mounting plates 71a, 71b are separated by a notch 78 formed along the X-axis at the center of the Y-axis direction of the mounting plate 71. These separate mounting plates 71a, 71b are connected (mechanical and electrical connection) by a single outer support plate 74 extending in the Y-axis direction.

[0112] In addition, in this embodiment, such as Figure 5B As shown, it can also be made Figure 5A The two independent recesses 46 and 46a arranged in the Y-axis direction are shown to be continuous and are designated as two shared recesses 46a and 46a. Alternatively, as Figure 5C As shown, it can also be made Figure 5B The two common recesses 46a and 46a are arranged in the X-axis direction and are continuous, and are designated as a common recess 46b.

[0113] Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the present invention.

[0114] For example, methods for forming the wiring portions 63a, 63b, 73a, and 73b include not only laser welding but also hot pressing (above 300°C). Hot pressing also allows for the formation of... Figure 2BThe solder pads of the solder 84 shown are heated to a high temperature (230-280°C) to connect the lead portions 12a, 12b, 14a, 14b of the winding wires 12, 14 to the terminal electrodes 60, 70. Alternatively, other methods for forming the connection portions 63a, 63b, 73a, 73b can be exemplified by arc welding, ultrasonic welding, etc.

[0115] In addition, in the terminal electrodes 60 and 70 of the above embodiments, the inner surfaces of the mounting portions 61 and 71 that contact the drum-shaped core 20 are preferably not plated in order to improve the bonding with the drum-shaped core. However, in order to improve the bonding with the solder 84, tin plating may be performed on the outer surface that becomes the bonding surface with the circuit board.

[0116] Furthermore, in the above-described embodiments, the overall shape of each flange portion 40 and 50 when viewed from the Z-axis direction is formed as a quadrilateral, but in the present invention, it may also be a circle, an ellipse, or other shapes.

[0117] Furthermore, in the above-described embodiment, the adhesive used for bonding the mounting portions 61, 71 of each terminal electrode 60 is configured not to enter the recesses 46, 46a, 46b formed on the outer end face of the flange portion 40, although a small amount may enter. However, minimizing the entry of adhesive into the recesses 46, 46a, 46b is preferable in terms of improving the adhesion or bonding force of each terminal electrode 60, 70 relative to the outer end face 42 of the flange portion.

[0118] Explanation of reference numerals in the attached figures

[0119] 2...coil device

[0120] 10... Coil section

[0121] 12...First Line

[0122] 14...Second line

[0123] 12a, 14a... First lead section (first end)

[0124] 12b, 14b... Second lead section (second end)

[0125] 15……Outer Resin

[0126] 20……Drum-shaped core (magnetic core)

[0127] 30……Core section

[0128] 40……First flange portion

[0129] 40a, 40b... Side view

[0130] 40c……Side of the notch

[0131] 42……Outer end face

[0132] 43……Inner surface

[0133] 44...gap

[0134] 46...Independent recess

[0135] 46a, 46b... share the recessed portion

[0136] 50……Second flange portion

[0137] 50a, 50b... Side view

[0138] 52……Outer end face

[0139] 53……Inner surface

[0140] 54……Chamfered section

[0141] 60, 60a... First terminal electrode

[0142] 70, 70b... Second terminal electrode

[0143] 61, 71... Installation pieces

[0144] 61a, 61b, 71a, 71b... Separate mounting pieces

[0145] 62a, 62b, 72a, 72b... Wiring stand-up pieces

[0146] 62a1, 62b1, 72a1, 72b1... retaining tablets

[0147] 63a, 73a... First wiring section

[0148] 63b, 73b... Second Wiring Section

[0149] 64, 64a, 64b, 74, 74a, 74b... outer upright pieces

[0150] 66a, 66b, 76a, 76b... Inner upright pieces

[0151] 68, 78... gaps

[0152] 80... Circuit board

[0153] 82……Wiring pattern

[0154] 84…… Solder.

Claims

1. A coil device comprising: The magnetic core has a core portion extending along a first axis direction and a magnetic core having a first flange portion and a second flange portion at each of the two ends of the core portion. The first and second wires wound around the core portion; First terminal electrode and second terminal electrode The first terminal electrode and the second terminal electrode are separately mounted on the first flange portion. The first terminal electrode has a first terminal first wiring portion connected to a first end of the first wire and a first terminal second wiring portion connected to a first end of the second wire. The second terminal electrode has a first terminal portion connected to the second end of the first wire and a second terminal portion connected to the second end of the second wire. The first terminal first wiring portion, the first terminal second wiring portion, the second terminal first wiring portion, and the second terminal second wiring portion are respectively disposed at four diagonal positions on the side of the first flange portion. The first terminal's first wiring portion and the first terminal's second wiring portion are positioned at four diagonal locations on the side side, along one side of the first flange portion, opposite to each other. The first wiring portion of the second terminal and the second wiring portion of the second terminal are disposed at four diagonal positions on the side side, opposite to each other along the other side of the first flange portion. The first terminal electrode has a first mounting plate mounted on the outer end face of the first flange in the first axial direction. The first terminal electrode also has a wiring stand for forming the first terminal's first wiring portion and the first terminal's second wiring portion, respectively. The wiring stand rises from the opposite end edges of the first mounting plate toward the side of the first flange portion along the first axial direction. The second terminal electrode has a second mounting piece mounted on the outer end face of the first flange in the first axial direction. The second terminal electrode also has a wiring stand for forming the first wiring portion and the second wiring portion of the second terminal, respectively. The wiring stand rises from the opposite end edges of the second mounting plate toward the side of the first flange portion along the first axial direction. The first mounting plate and the second mounting plate constitute a mounting surface.

2. The coil device according to claim 1, characterized in that: The first terminal's first wiring portion and the second terminal's first wiring portion of the second terminal electrode are positioned diagonally opposite each other in one of the four diagonal positions on the side surface. The second terminal of the first terminal and the second terminal of the second terminal electrode are arranged at diagonal positions among the four diagonal positions on the side side.

3. The coil device according to claim 1, characterized in that: A notch is formed on the side of the first flange portion on which the wiring stand is formed.

4. The coil device according to claim 1 or 2, characterized in that: A recess is formed on the outer end face of the first flange portion. The first terminal electrode or the second terminal electrode has an inner stand-up tab that loosely enters the recess.

5. The coil device according to claim 4, characterized in that: A predetermined gap is formed between the side wall of the recess connected to the bottom wall and the front end of the inner upright piece entering the recess.

6. The coil device according to claim 1, characterized in that: The first terminal electrode or the second terminal electrode further has an outer raised piece that rises from the end edge of the first mounting piece or the second mounting piece toward the side of the first flange portion.

7. The coil device according to claim 6, characterized in that: The first mounting plate has a pair of separate mounting plates that are respectively connected to the first wiring portion of the first terminal and the second wiring portion of the first terminal, and the separate mounting plates are connected by the outer upright plate.

8. The coil device according to claim 1, characterized in that: The first terminal first wiring portion and the second terminal second wiring portion of the first terminal electrode are connected by the first mounting plate.

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