Coil device

Abstract

To provide a coil device with reduced stray capacitance.SOLUTION: A coil device has: a drum core having a first flange part, a second flange part, and a winding core part; a first terminal part provided on the first flange part; a second terminal part provided on the second flange part; a first coil which is wound around the winding core part first portion of the winding core part, and which is connected to the first terminal part and the second terminal part; and a second coil which is wound around the winding core part second portion of the winding core part, and which is connected to the second terminal part and the first terminal part. On a winding core first lateral surface and a winding core second lateral surface, the winding core part has a first lateral surface protrusion and a second lateral surface protrusion which are located between the winding core part first portion and the winding core part second portion. The lead-out part of the first coil is connected to the second terminal part after being engaged with the lower end of the first lateral surface protrusion or with the upper end of the first lateral surface protrusion. The lead-out part of the second coil is connected to the first terminal part after being engaged with the upper end of the second lateral surface protrusion or with the lower end of the second lateral surface protrusion.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a coil device that can be used, for example, as a DMI or the like.

Background Art

[0002] A coil device having two coils in a winding core portion of a core is disclosed (Patent Document 1). In this coil device, by winding each coil around different portions of the same winding core portion, the electromagnetic actions generated by the two coils are balanced.

[0003] However, in such a coil device, in a portion where a lead wire from one coil approaches a winding portion of the other coil, extra stray capacitance may occur, and problems such as a decrease in impedance characteristics due to the generation of stray capacitance have arisen.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of the above circumstances, the present invention has been made, and an object thereof is to provide a coil device capable of preventing the generation of stray capacitance.

Means for Solving the Problems

[0006] To achieve the above object, a coil device according to the present invention includes a drum core having a first flange portion and a second flange portion, and a winding core portion connecting the first flange portion and the second flange portion, a plurality of first terminal portions provided on the first flange portion, and a plurality of second terminal portions provided on the second flange portion, It is wound around a first part of the core part, which is a part closer to the first flange part, in a plurality of turns. One end is connected to one of the first terminal parts, and the other end is connected to one of the second terminal parts. A first coil; It is wound around a second part of the core part, which is a part closer to the second flange part, in a plurality of turns. One end is connected to one of the second terminal parts, and the other end is connected to one of the first terminal parts. A second coil; and it has On the core first side surface and the core second side surface that connect the core upper surface and the core lower surface and face opposite directions, first side surface protrusions and second side surface protrusions are formed between the first part of the core part and the second part of the core part on the core first side surface and the core second side surface. The lead-out part of the first coil led out from the first part of the core part is engaged with the lower end of the first side surface protrusion at a position the same as or higher than the core lower surface or the upper end of the first side surface protrusion at a position the same as or lower than the core upper surface, and then connected to the second terminal part. The lead-out part of the second coil led out from the second part of the core part is engaged with the upper end of the second side surface protrusion at a position the same as or lower than the core upper surface or the lower end of the second side surface protrusion at a position the same as or higher than the core lower surface, and then connected to the first terminal part.

[0007] In such a coil device, after the lead-out portion of each coil engages with the upper or lower end of the first or second side protrusion, it is connected to the first or second terminal portion on the side opposite to the core portion of the winding core to be wound. For example, when the winding direction is the right-handed screw direction and the terminal positions are parallel, if there is no side protrusion, the lead-out portion passes directly above the winding portion of another coil. By engaging with the side protrusion, it can avoid passing directly above the winding portion of another coil and be connected to the first or second terminal portion. Also, for example, when the winding direction is the left-handed screw direction and the terminal positions are parallel, if there is no side protrusion, the lead-out portion passes near the side portion of the winding portion of another coil. By engaging with the side protrusion, it can avoid passing near the side portion of the winding portion of another coil and connect the lead-out portion to the first or second terminal portion. Note that when the winding direction is the right-handed screw direction and the terminal positions are cross, it is the same as the case when the winding direction is the left-handed screw direction and the terminal positions are parallel. When the winding direction is the left-handed screw direction and the terminal positions are cross, it is the same as the case when the winding direction is the right-handed screw direction and the terminal positions are parallel. Thereby, in the coil device, the lead-out portion of each coil can pass through a position farther from the winding portion of another coil compared to the case where there is no side protrusion, and the generation of stray capacitance can be prevented. Also, since the upper end of the side protrusion is at the same level or lower than the upper surface of the core, and the lower end of the side protrusion is at the same level or higher than the lower surface of the core, it is possible to prevent the problem that the DC resistance (Rdc) increases when the coil engages with the upper or lower end of the side protrusion.

[0008] Also, for example, a plate core may be further provided above the drum core and connecting the upper surfaces of the flange portions of the first flange portion and the second flange portion.

[0009] A coil device having such a plate core can form a closed magnetic circuit with a simple structure. Also, since the lead-out portion of each coil engages with the upper or lower end of the first or second side protrusion, the lead-out portion does not need to pass through the narrow space between the plate core and directly above the winding portion of another coil, which is also advantageous from the perspective of reducing the height.

[0010] Further, for example, the second coil connection first terminal portion, which is one of the plurality of first terminal portions and to which the lead portion of the second coil is connected, may be disposed closer to the second side surface of the bobbin than the first side surface of the bobbin. The first coil connection second terminal portion, which is one of the plurality of second terminal portions and to which the lead portion of the first coil is connected, may be disposed closer to the first side surface of the bobbin than the second side surface of the bobbin.

[0011] The first or second terminal portion to which the lead portion of each coil is connected is disposed near the first or second side surface of the bobbin where the first or second side surface protrusion with which each lead portion engages is formed, thereby avoiding directly above the winding portion of other coils and enabling the lead portion to be connected to the first or second terminal portion.

[0012] Further, for example, the lead portion of the first coil may engage with the lower end of the first side surface protrusion located at a position higher than the lower surface of the bobbin and then be connected to the second terminal portion. The lead portion of the second coil may engage with the upper end of the second side surface protrusion located at a position lower than the upper surface of the bobbin and then be connected to the first terminal portion.

[0013] In a coil device in which the winding directions of the first coil and the second coil are opposite and the terminals are arranged in parallel, with such a configuration, the stray capacitance can be effectively reduced.

[0014] Further, for example, the number of turns of the second coil wound around the second portion of the bobbin core may be the same as the number of turns of the first coil wound around the first portion of the bobbin core.

[0015] Such a coil device can be suitably used as a noise filter such as a DMI or a common mode coil.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0017] Hereinafter, a coil device according to the present disclosure will be described with reference to embodiments.

[0018] As an embodiment of the coil device according to the present disclosure, for example, the overall configuration of a differential mode inductor (DMI) having a function as a noise filter will be described. However, the coil device according to the present disclosure is not limited to only those used as a differential mode inductor (DMI), and coil devices other than DMI, such as those used as a common mode filter, are also included in the coil device according to the present disclosure.

[0019] FIG. 1 is a schematic perspective view of a coil device 10 according to an embodiment of the present disclosure. As shown in FIG. 1, the coil device 10 has a substantially rectangular parallelepiped shape as a whole, and includes a first coil 50, a second coil 60, a drum core 20 having a winding core portion 22 around which the first coil 50 and the second coil 60 are wound, and a plate core 70. Further, the coil device 10 has a plurality of first terminal portions 30 provided on the first flange portion 27 of the drum core 20 and a plurality of second terminal portions 40 provided on the second flange portion 28.

[0020] The coil device 10 has an outer dimension of, for example, 4.3 to 4.7 mm in the X-axis direction, 2.6 to 3.0 mm in the Z-axis direction, and 3.0 to 3.4 mm in the Y-axis direction. However, the size of the coil device 10 is not limited to this.

[0021] The drum core 20 has a first flange portion 27 and a second flange portion 28, and a core portion 22 that connects the first flange portion 27 and the second flange portion 28. The core portion 22 extends along the Y-axis. The first flange portion 27 is provided on one end side (the negative Y-axis direction side) of the core portion 22, and the second flange portion 28 is provided on the other end side (the outside of the positive Y-axis direction) of the core portion 22. That is, the core portion 22 connects the opposing surfaces of the first flange portion 27 and the second flange portion 28. In the present disclosure, the direction from the first flange portion 27 to the second flange portion 28 in the core portion 22 may be referred to as the positive direction of the Y-axis, and the direction opposite thereto may be referred to as the negative direction. Also, the direction perpendicular to the mounting surface of the coil device 10 and from the mounting surface toward the core portion 22 and the plate core 70 may be referred to as the positive direction or upward of the Z-axis, and the direction opposite thereto may be referred to as the negative direction or downward of the Z-axis. The X-axis, Y-axis, and Z-axis are perpendicular to each other.

[0022] FIG. 2 is a front view of the main body portion of the coil device 10 shown in FIG. 1 excluding the plate core 70 as viewed from the front, and FIG. 3 is a plan view of the main body portion of the coil device 10 as viewed from above. As can be understood from FIGS. 2 and 3, the core portion 22 of the drum core 20 has a substantially rectangular parallelepiped outer shape, and the YZ cross-section is substantially rectangular. The core portion 22 has a core upper surface 22a facing upward (the positive Z-axis direction), a core lower surface 22b facing downward (the negative Z-axis direction), a core first side surface 22c and a core second side surface 22d facing the side (the Y-axis direction).

[0023] The core first side surface 22c and the core second side surface 22d connect the core upper surface 22a and the core lower surface 22b and face opposite directions. In the present disclosure, the direction from the core first side surface 22c to the core second side surface 22d may be referred to as the positive direction of the X-axis, and the direction opposite thereto may be referred to as the negative direction.

[0024] As shown in FIGS. 2 and 3, the first flange portion 27 and the second flange portion 28 have a substantially symmetrical shape with the core portion 22 interposed therebetween. As shown in FIG. 1, the first flange portion 27 and the second flange portion 28 are substantially rectangular when viewed from the Y-axis direction and have a substantially rectangular parallelepiped three-dimensional shape.

[0025] As shown in FIG. 3, the upper surface 27a of the flange portion of the first flange portion 27 facing upward has a central convex portion 27aa, a first side concave portion 27ab disposed on the negative X-axis side of the central convex portion 27aa, and a second side concave portion 27ac disposed on the positive X-axis side of the central convex portion 27aa. When viewed from above, the central convex portion 27aa is disposed on the extension of the core portion 22 and is located at the central portion in the X-axis direction. The central convex portion 27aa is located above the first side concave portion 27ab and the second side concave portion 27ac.

[0026] The upper surface 28a of the flange portion of the second flange portion 28 facing upward also has a central convex portion 28aa, a first side concave portion 28ab disposed on the negative X-axis side of the central convex portion 27aa, and a second side concave portion 28ac disposed on the positive X-axis side of the central convex portion 27aa, similar to the first flange portion 27. When viewed from above, the central convex portion 28aa is disposed on the extension of the core portion 22 and is located at the central portion in the X-axis direction. The central convex portion 28aa is located above the first side concave portion 28ab and the second side concave portion 28ac.

[0027] As shown in FIG. 1, the plate core 70 is disposed above the drum core 20. The plate core 70 connects the upper surfaces 27a and 28b of the first flange portion 27 and the second flange portion 28 of the drum core 20. As shown in FIG. 1, in the coil device 10 according to the embodiment, the plate core 70 connects the central convex portion 27aa of the upper surface 27a of the first flange portion 27 and the central convex portion 28aa of the upper surface 28a of the second flange portion 28.

[0028] As shown in FIG. 3, the plurality of first terminal portions 30 include a first coil connection first terminal portion 31 and a second coil connection first terminal portion 32. Both the first coil connection first terminal portion 31 and the second coil connection first terminal portion 32 are provided on the first flange portion 27. However, the first coil connection first terminal portion 31 is disposed closer to the first side surface 22c of the bobbin than the second side surface 22d of the bobbin, while the second coil connection first terminal portion 32 is disposed closer to the second side surface 22d of the bobbin than the first side surface 22c of the bobbin.

[0029] FIG. 5 is a rear view of the main body portion of the coil device 10 as viewed from the rear. As shown in FIG. 2 which is a front view and FIG. 5 which is a rear view, the first coil connection first terminal portion 31 and the second coil connection first terminal portion 32 include connection portions 31a, 32a provided on the upper surface 27a of the flange portion of the first flange portion 27, mounting portions 31b, 32b provided on the lower surface 27b of the flange portion of the first flange portion 27, and connection portions disposed on the end surface of the first flange portion 27 connecting the connection portions 31a, 32a and the mounting portions 31b, 32b. As shown in FIG. 3, the connection portion 31a of the first coil connection first terminal portion 31 is disposed in the first side recess 27ab close to the first side surface 22c of the bobbin, and the connection portion 32a of the second coil connection first terminal portion 32 is disposed in the second side recess 27ac close to the second side surface 22d of the bobbin.

[0030] As shown in FIG. 3, the plurality of second terminal portions 40 include a first coil connection second terminal portion 41 and a second coil connection second terminal portion 42. Both the first coil connection second terminal portion 41 and the second coil connection second terminal portion 42 are provided on the second flange portion 28. However, the first coil connection second terminal portion 41 is disposed closer to the first side surface 22c of the bobbin than the second side surface 22d of the bobbin, while the second coil connection second terminal portion 42 is disposed closer to the second side surface 22d of the bobbin than the first side surface 22c of the bobbin.

[0031] As shown in FIG. 2 which is a front view and FIG. 5 which is a rear view, the first coil connection second terminal portion 41 and the second coil connection second terminal portion 42 include connection line portions 41a, 42a provided on the upper surface 28a of the flange portion of the second flange portion 28, mounting portions 41b, 42b provided on the lower surface 28b of the flange portion of the second flange portion 28, and a connection portion that connects the connection line portions 41a, 42a and the mounting portions 41b, 42b and is disposed on the end surface of the second flange portion 28. As shown in FIG. 3, the connection line portion 41a of the first coil connection second terminal portion 41 is disposed in the side portion first recess 28ab close to the first side surface 22c of the bobbin core, and the connection line portion 42a of the second coil connection second terminal portion 42 is disposed in the side portion second recess 28ac close to the second side surface 22d of the bobbin core.

[0032] As shown in FIG. 2, the first coil connection first terminal portion 31 provided on the first flange portion 27 and the first coil connection second terminal portion 41 provided on the second flange portion 28 are disposed substantially symmetrically with respect to a symmetry axis extending in the Z-axis direction through the center of the bobbin core portion 22. Further, as shown in FIG. 5, the second coil connection first terminal portion 32 provided on the first flange portion 27 and the second coil connection second terminal portion 42 provided on the second flange portion 28 are disposed substantially symmetrically with respect to a symmetry axis extending in the Z-axis direction through the center of the bobbin core portion 22.

[0033] As shown in FIGS. 2 and 3, the coil device 10 has two coils, a first coil 50 and a second coil 60. The first coil 50 and the second coil 60 are each composed of a covered electric wire or the like, and the first coil 50 and the second coil 60 are insulated from each other.

[0034] As shown in FIG. 2, one end of the first coil 50 is connected to the first coil connection first terminal portion 31 which is one of the first terminal portions 30, and the other end is connected to the first coil connection second terminal portion 41 which is one of the second terminal portions 40. Further, the first coil 50 has a first coil winding portion 52 wound around a plurality of turns on the first portion 23 of the bobbin core portion 22 which is a part of the portion close to the first flange portion 27 in the bobbin core portion 22.

[0035] The first coil 50 includes, in addition to the first coil winding portion 52, a lead-out portion 51 of the first coil 50 drawn from the first part 23 of the core portion to the second terminal portion 41 of the first coil connection, and an original lead-out portion 53 of the first coil 50 drawn from the first part 23 of the core portion to the first terminal portion 31 of the first coil connection. The end of the original lead-out portion 53, which is also one end of the first coil 50, is connected to the connecting wire portion 31a of the first coil connection first terminal portion 31. Also, the end of the lead-out portion 51, which is the other end of the first coil 50, is connected to the connecting wire portion 41a of the first coil connection second terminal portion 41.

[0036] As shown in FIG. 1, the connecting wire portion 31a of the first coil connection first terminal portion 31 and the connecting wire portion 41a of the first coil connection second terminal portion 41 are arranged in the gap between the lower surface of the plate core 70 and the upper surface 27a, 28a of the flange portion of the first flange portion 27 or the second flange portion 28.

[0037] As shown in FIG. 5, one end of the second coil 60 is connected to the second coil connection second terminal portion 42, which is one of the second terminal portions 40, and the other end is connected to the second coil connection first terminal portion 32, which is one of the first terminal portions 30. Also, the second coil 60 has a second coil winding portion 62 wound around a plurality of turns on the second part 24 of the core portion, which is a part of the core portion 22 close to the second flange portion 28.

[0038] The second coil 60 includes, in addition to the second coil winding portion 62, a lead-out portion 61 of the second coil 60 drawn from the second part 24 of the core portion to the second coil connection first terminal portion 32, and an original lead-out portion 63 of the second coil 60 drawn from the second part 24 of the core portion to the second coil connection second terminal portion 42. The end of the original lead-out portion 63, which is also one end of the second coil 60, is connected to the connecting wire portion 42a of the second coil connection second terminal portion 42. Also, the end of the lead-out portion 61, which is the other end of the second coil 60, is connected to the connecting wire portion 32a of the second coil connection first terminal portion 32.

[0039] As can be understood from FIG. 1, the connecting wire portions 32a of the second coil connecting first terminal portion 32 and the connecting wire portions 42a of the second coil connecting second terminal portion 42 are arranged in the gaps between the lower surface of the plate core 70 and the flange upper surfaces 27a, 28a of the first flange portion 27 or the second flange portion 28, similar to the connecting wire portions 31a, 41a.

[0040] FIG. 4 is a bottom view of the main body portion of the coil device 10 shown in FIG. 1, excluding the plate core 70, as viewed from below. As shown in FIGS. 2 to 5, on the first core side surface 22c of the core portion 22, a first side surface protrusion 25 is formed between the first core portion 23 and the second core portion 24 on the first core side surface 22c. Also, on the second core side surface 22d of the core portion 22, a second side surface protrusion 26 is formed between the first core portion 23 and the second core portion 24.

[0041] As shown in FIGS. 2 to 4, on the first core side surface 22c, the first side surface protrusion 25 protrudes toward the negative X-axis side with respect to the surfaces of the portions constituting the first core portion 23 and the second core portion 24. The upper end 25a of the first side surface protrusion 25 is at the same level as or lower than the core upper surface 22a, and the lower end 25b of the first side surface protrusion 25 is at the same level as or higher than the core lower surface 22b.

[0042] Also, as shown in FIGS. 3 to 5, on the second core side surface 22d, the second side surface protrusion 26 protrudes toward the positive X-axis side with respect to the surfaces of the portions constituting the first core portion 23 and the second core portion 24. The upper end 26a of the second side surface protrusion 26 is at the same level as or lower than the core upper surface 22a, and the lower end 26b of the second side surface protrusion 26 is at the same level as or higher than the core lower surface 22b.

[0043] As shown in Fig. 2, the lead portion 51 of the first coil 50 drawn from the first part 23 of the core part is engaged with the lower end 25b of the first side protrusion 25 after being drawn from the first part 23 of the core part, and then is connected to the first coil connection second terminal part 41. Further, as shown in Fig. 5, the lead portion 61 of the second coil 60 drawn from the second part 24 of the core part is engaged with the upper end 26a of the second side protrusion 26 after being drawn from the second part 24 of the core part, and then is connected to the second coil connection first terminal part 32.

[0044] As can be understood from Figs. 2 and 3, the first coil winding portion 52 of the first coil 50 is wound around the first part 23 of the core part in the right-handed screw direction (the shape that advances inward by right rotation). On the other hand, as can be understood from Figs. 3 and 5, the second coil winding portion 62 of the second coil 60 is wound around the second part 24 of the core part in the left-handed screw direction (the shape that advances inward by left rotation). Since the first coil 50 is in the right-handed screw direction, the lead portion 51 of the first coil 50 is engaged with the lower end 25b of the first side protrusion 25 and then connected to the first coil connection second terminal part 41. In contrast, since the second coil 60 is in the left-handed screw direction, the lead portion 61 of the second coil 60 is engaged with the upper end 26a of the second side protrusion 26 and then connected to the second coil connection first terminal part 32.

[0045] However, the winding direction of the first coil winding portion 52 of the first coil 50 is not limited to only the right-handed screw direction, and the first coil winding portion 52 of the first coil 50 may be wound around the first part 23 of the core part in the left-handed screw direction. In such a case, the lead portion 51 of the first coil 50 can be engaged with the upper end 25a of the first side protrusion 25 after being drawn from the first part 23 of the core part, and then connected to the first coil connection second terminal part 41. Whether the first coil 50 is in the right-handed screw or left-handed screw, the first coil connection first terminal part 31 and the first coil connection second terminal part 41 to which the end of the first coil 50 is connected are preferably arranged on the same side with respect to the X-axis direction, that is, the side close to the first side surface 22c of the core.

[0046] In the coil device 10, the lower end 25b of the first side surface protrusion 25 is located at a position higher than the lower surface 22b of the bobbin (see FIG. 2). Therefore, the lead-out portion 51 of the first coil 50 engages with the lower end 25b of the first side surface protrusion 25 located at a position higher than the lower surface 22b of the bobbin and then is connected to the first coil connection second terminal portion 41. However, the lower end 25b of the first side surface protrusion 25 is not limited to being only at a position higher than the lower surface 22b of the bobbin. Like the drum core 120 according to the modified example shown in FIG. 6, the lower end 125b of the first side surface protrusion 125 may be at the same height as the lower surface 122b of the bobbin. Similarly, the upper end 125a of the first side surface protrusion 125 may be at the same height as the upper surface 122a of the bobbin.

[0047] Also, the winding direction of the second coil winding portion 62 of the second coil 60 is not limited to only the left-handed screw direction. The second coil winding portion 62 of the second coil 60 may be wound in the right-handed screw direction around the second portion 24 of the bobbin core. In such a case, after the lead-out portion 61 of the second coil 60 is drawn out from the second portion 24 of the bobbin core, it can engage with the lower end 26b of the second side surface protrusion 26 and then be connected to the second coil connection first terminal portion 32. Whether the second coil 60 is a right-handed screw or a left-handed screw, the second coil connection first terminal portion 32 and the second coil connection second terminal portion 42 to which the end of the first coil 50 is connected are preferably arranged on the same side in the X-axis direction, that is, the side closer to the second side surface 22d of the bobbin.

[0048] In the coil device 10, the upper end 25a of the second side surface protrusion 26 is located at a position lower than the upper surface 22a of the bobbin (see FIG. 5). Therefore, the lead-out portion 61 of the second coil 60 engages with the upper end 26a of the second side surface protrusion 26 located at a position lower than the upper surface 22a of the bobbin and then is connected to the second coil connection first terminal portion 32. However, the upper end 26a of the second side surface protrusion 26 is not limited to being only at a position lower than the upper surface 22a of the bobbin. Like the drum core 120 according to the modified example shown in FIG. 6, the upper end 126a of the second side surface protrusion 126 may be at the same height as the upper surface 122a of the bobbin. Similarly, the lower end of the second side surface protrusion 126 may be at the same height as the lower surface 122b of the bobbin.

[0049] In the coil device 10, the number of turns of the second coil 60 wound around the second part 24 of the bobbin core is the same as the number of turns of the first coil 50 wound around the first part 23 of the bobbin core. Such a coil device 10 can be suitably used as a noise filter such as a DMI or a common mode coil. However, the number of turns of the first coil 50 and the second coil 60 may be different from each other. Note that the same number of turns of the first coil 50 and the second coil 60 means a case where the difference in the number of turns of the first coil 50 and the second coil 60 is less than one turn.

[0050] As shown in FIGS. 1 to 5, in the coil device 10, after the lead-out portions 51 and 61 of the respective coils 50 and 60 are engaged with the upper end 26a or the lower end 25b of the first or second side protrusions 25 and 26, they are connected to the first or second terminal portions 32 and 41 on the side opposite to the first or second part 23 and 24 of the bobbin core 22 to be wound. Thereby, the lead-out portion 51 of the first coil 50 whose winding direction is the right-hand screw direction, if there is no first side protrusion 25, as shown by the two-dot chain line in FIG. 3, the lead-out portion passes directly above the second coil winding portion 62 of the second coil 60. By engaging with the lower end 25b of the first side protrusion 25, it can avoid passing directly above the second coil winding portion 62 and be connected to the first coil connection second terminal portion 41.

[0051] In this way, by avoiding the place where the lead-out portion 51 of the first coil 50 passes directly above the second coil winding portion 62 of the second coil 60, the generation of stray capacitance in the coil device 10 can be reduced. This is because there is a plate core 70 above the second coil winding portion 62, and if the lead-out portion 51 passes through such a narrow space, the lead-out portion 51 has to approach the second coil winding portion 62. On the other hand, as shown in FIG. 3, there is relatively more space on the side (negative X-axis direction side) of the second coil winding portion 62 due to the arrangement space of the first coil connection first and second terminal portions 31 and 41 and the like. Therefore, by passing the lead-out portion 51 of the first coil 50 on the side of the second coil winding portion 62, the distance between the lead-out portion 51 and the second coil winding portion 62 can be increased, and the generation of stray capacitance can be reduced.

[0052] As shown in FIG. 3, when the main body portion of the coil device 10 is viewed from above, it is preferable from the viewpoint of reducing the generation of stray capacitance that the lead-out portion 51 of the first coil 50 does not overlap the second coil winding portion 62 and the lead-out portion 61 of the second coil 60 does not overlap the first coil winding portion 52.

[0053] Further, the lead-out portion 61 of the second coil 60 whose winding direction is the left-handed screw direction, if there is no second side surface protrusion 26, as shown by the two-dot chain line 65 in FIG. 5, the lead-out portion passes by the side of the first coil winding portion 52 of the first coil 50. By engaging with the upper end 26a of the second side surface protrusion 26, it is possible to avoid passing near the second coil winding portion 62 as much as possible and connect to the second coil connection first terminal portion 32.

[0054] In this way, by avoiding the lead-out portion 61 of the second coil 60 from passing near the side of the first coil winding portion 52 of the first coil 50 as much as possible, the generation of stray capacitance in the coil device 10 can be reduced. However, since the space on the side of the first coil winding portion 52 has more margin than the upper space, even if there is no second side surface protrusion 26, the problem is smaller compared to the case where there is no first side surface protrusion 25. For example, the height difference between the upper end 26a of the second side surface protrusion 26 and the upper surface 22a of the bobbin core may be larger than that shown in FIG. 5.

[0055] Further, since the lower end 25b of the first side protrusion 25 is at the same level as or higher than the lower surface 22b of the bobbin, and the upper end 26a of the second side protrusion 26 is at the same level as or higher than the upper surface 22a of the bobbin, it is possible to prevent the problem that the DC resistance (Rdc) increases when the first and second coils 50, 60 engage with the upper or lower ends of the side protrusions 25, 26. If the lower end 25b of the first side protrusion 25 is lower than the lower surface 22b of the bobbin and the upper end 26a of the second side protrusion 26 is higher than the upper surface 22a of the bobbin, a part of the first and second coils 50, 60 will be separated from the bobbin portion 22 near the engagement position with these protrusions, increasing the portion that contributes poorly to the performance of the coil device 10 in the first and second coils 50, 60.

[0056] Also, since the coil device 10 has the plate core 70, it is possible to form a closed magnetic circuit with a simple structure. Further, since the lead portions 51, 61 do not pass between the plate core 70 and the first or second coil winding portions 52, 62, it is possible to narrow the gap between the plate core 70 and the first and second coil winding portions 52, 62 and reduce the height.

[0057] As shown in FIG. 3, the lead portion 51 of the first coil 50 engages with the first side protrusion 25 formed on the first side surface 22c of the bobbin on the side closer to the first coil connection second terminal portion 41 to which the end of the lead portion 51 is connected. On the other hand, the lead portion 61 of the second coil 60 engages with the second side protrusion 26 formed on the second side surface 22d of the bobbin on the side closer to the second coil connection first terminal portion 32 to which the end of the lead portion 61 is connected. That is, the first coil connection second terminal portion 41 or the second coil connection first terminal portion 32 to which the lead portions 51, 61 are connected and the first side protrusion 25 or the second side protrusion 26 with which the lead portions 51, 61 engage are arranged on the same side with respect to the winding central axis. Thereby, each of the lead portions 51, 61 can avoid passing directly above the winding portion of another coil different from the coils of the lead portions 51, 61, effectively preventing the generation of stray capacitance.

[0058] (Manufacturing method of the coil device 10) Next, a manufacturing method of the coil device 10 as an embodiment of the present invention will be specifically described.

[0059] In the manufacture of the coil device 10, first, a drum core 20, a plate core 70, wires (coated conductors) that will become the first coil 50 and the second coil 60, a plurality of first terminal portions 30, and a plurality of second terminal portions 40 are prepared. The drum core 20 and the plate core 70 are each composed of separate magnetic body members, and although it is preferable that these materials are the same, they may be composed of separate magnetic body materials.

[0060] Examples of the magnetic body material include, for example, magnetic materials with relatively high magnetic permeability, such as Ni-Zn-based ferrites, Mn-Zn-based ferrites, or metallic magnetic bodies. By molding and sintering powders of these magnetic materials, the drum core and the plate core 70 are produced. In the drum core 20, a winding core portion 22, a first side surface protrusion portion 25, a second side surface protrusion portion 26, a first flange portion 27, and a second flange portion 28 are integrally formed.

[0061] Next, a first coil connection first terminal portion 31 and a second coil connection first terminal portion 32 that constitute the plurality of first terminal portions 30 are attached to the first flange portion 27. Also, a first coil connection second terminal portion 41 and a second coil connection second terminal portion 42 that constitute the plurality of second terminal portions 40 are attached to the second flange portion 28. At this time, a non-conductive adhesive may be interposed and adhered between the terminal portion and the flange portion.

[0062] The first terminal portion 30 and the second terminal portion 40 are formed into the shapes shown in FIG. 1 and the like by performing bending processing on a strip-shaped metal plate mainly composed of a copper alloy such as phosphor bronze or brass, or phosphorus, copper, tin, iron, zinc, etc. Also, on the surface of each of the terminal portions 31, 32, 41, 42 on the side opposite to the side facing the flange portion, a known plating layer such as nickel or tin may be formed. Note that the terminals are not limited to metal plates, and a metal paste may be applied to the flange portion and baked to form them.

[0063] Next, as shown in FIG. 1, a wire, which is a raw material of the first coil 50, is wound around the first part 23 of the bobbin core by a predetermined number of turns to form the first coil winding part 52 of the first coil 50. For one end of the first coil 50, the end of the original lead-out part 53 drawn out from the first coil winding part 52 is fixed to the connecting wire part 31a of the first coil connecting first terminal part 31. For the other end of the first coil 50, a part of the lead-out part 51 is engaged with the lower end 25b of the first side surface protrusion 25, and the end of the lead-out part 51 is fixed to the connecting wire part 41a of the first coil connecting second terminal part 41.

[0064] Regarding the second coil 60 as well, in the same manner as the first coil 50, a wire, which is a raw material of the second coil 60, is wound around the second part 24 of the bobbin core by a predetermined number of turns to form the second coil winding part 62 of the second coil 60. For one end of the second coil 60, the end of the original lead-out part 63 drawn out from the second coil winding part 62 is fixed to the connecting wire part 42a of the second coil connecting second terminal part 42. For the other end of the second coil 60, a part of the lead-out part 61 is engaged with the upper end 26a of the second side surface protrusion 26, and the end of the lead-out part 61 is fixed to the connecting wire part 32a of the second coil connecting first terminal part 32.

[0065] When forming the first coil 50 and the second coil 60, the winding of the wire can be performed by a known method such as winding with an automatic winding device or manual winding. Also, the formation of the first coil winding part 52 and the second coil winding part 62 may be performed before fixing the end of the wire to the terminal, or may be performed after fixing either end of the wire to the terminal, and the formation procedure is not particularly limited.

[0066] The connection method between the ends of the first coil 50 and the second coil 60 and the connecting wire parts 31a, 32a, 41a, 42a of each terminal is not particularly limited, but for example, methods such as laser welding, thermocompression bonding, soldering can be adopted.

[0067] Finally, the plate core 70 is fixed to the drum core 20 on which the first and second coils 50 and 60 are formed to obtain the coil device 10.

[0068] As described above, in the coil device 10 according to the present disclosure, after the lead portions 51 and 61 of the coils 50 and 60 are engaged with the lower end 25b of the first side surface protrusion 25 or the upper end 26a of the second side surface protrusion 26, they are connected to the first coil connection second terminal portion 41 or the second coil connection first terminal portion 32 on the side opposite to the first or second portion 23 or 24 of the winding core portion 22 to be wound. By engaging the lead portions 51 and 61 with the lower end 25b of the first side surface protrusion 25 or the upper end 26a of the second side surface protrusion 26, the distance between the lead portions 51 and 61 and the winding portions 52 and 62 of the other coils can be increased as compared with the case where these first side surface protrusion 25 and second side surface protrusion 26 are not provided. Thereby, the stray capacitance generated in the coil device 10 can be reduced. Since the coil device 10 can reduce the generation of stray capacitance, it is also possible to preferably prevent a decrease in impedance characteristics due to the generation of stray capacitance.

[0069] As described above, the coil device according to the present disclosure has been described with reference to the embodiments. However, the coil device according to the present disclosure is not limited to only the coil device 10 shown in the embodiments. Needless to say, the technical scope of the coil device according to the present disclosure includes coil devices according to various other embodiments and modifications. For example, the coil device 10 may have coils other than the first coil 50 and the second coil 60, and the first terminal portion 30 and the second terminal portion 40 may each include three or more terminal portions.

[0070] Also, the coil device 10 may not have the plate core 70. Furthermore, the shape of the drum core 20 is not limited to only those shown in FIGS. 1 to 5. FIG. 6 is a perspective view of a drum core 120 according to a modification. Similar to the drum core 20 shown in FIG. 1 and the like, the drum core 120 has a first flange portion 127, a second flange portion 128, a winding core portion 122, etc. A first side surface protrusion 125 is formed on the winding core first side surface 122c of the winding core portion 122, and a second side surface protrusion 126 is formed on the winding core second side surface 122d of the winding core portion 122.

[0071] The upper ends 125a, 126a and the lower end 125b of the drum core 120's first and second side protrusions 125, 126 are at the same height as the upper surface 122a and the lower surface 122b of the bobbin core respectively. A coil device that uses the drum core 120 shown in Fig. 6 in place of the drum core 20 shown in Fig. 1 etc. also has the same effect as the coil device 10 according to the first embodiment. However, from the viewpoint of suppressing the DC resistance of the coil device, it is more preferable that the upper ends 25a, 26a of the first and second side protrusions 25, 26 are at a position lower than the upper surface 22a of the bobbin core and the lower ends 25b, 26b are at a position higher than the lower surface 22b of the bobbin core, like the drum core 20 shown in Fig. 1 etc.

Explanation of Signs

[0072] 10…Coil device 20, 120…Drum core 22, 122…Bobbin core part 23…First part of the bobbin core 24…Second part of the bobbin core 22a, 122a…Upper surface of the bobbin core 22b, 122b…Lower surface of the bobbin core 22c, 122c…First side of the bobbin core 25, 125…First side protrusion 25a, 125a…Upper end 25b, 125b…Lower end 22d, 122d…Second side of the bobbin core 26, 126…Second side protrusion 26a, 126a…Upper end 26b…Lower end 27, 127…First flange part 27a…Upper surface of the flange part 27aa…Central convex part 27ab…First side concave part of the side part 27ac…Second side concave part of the side part 27b…Lower surface of the flange part 28, 128…Second flange part 28a…Upper surface of the flange part 28aa…Central convex part 28ab…First side concave part of the side part 28ac…Second side concave part of the side part 28b…Lower surface of the flange part 30…First terminal part 31…First coil connection first terminal part 31a…Jumper part 31b…Mounting part 32…Second coil connection first terminal part 32a…Jumper part 32b…Mounting part 40…Second terminal part 41…First coil connection second terminal part 41a…Jumper part 41b…Mounting part 42…Second coil connection second terminal part 42a…Jumper part 42b…Mounting part 50…First coil 51…Lead-out part 52…First coil winding part 53…Original lead-out part 60…Second coil 61…Lead-out part 62…Second coil winding part 63…Original lead-out part 70…Plate core

Claims

1. A drum core having a first flange portion and a second flange portion, and a bobbin portion connecting the first flange portion and the second flange portion; A plurality of first terminal portions provided on the first flange portion, and a plurality of second terminal portions provided on the second flange portion; A first coil wound around a first part of the bobbin portion near the first flange portion, with one end connected to one of the first terminal portions and the other end connected to one of the second terminal portions; A second coil wound around a second part of the bobbin portion near the second flange portion, with one end connected to one of the second terminal portions and the other end connected to one of the first terminal portions; On the bobbin portion, a first side surface and a second side surface that connect the upper surface and the lower surface of the bobbin and face opposite directions are provided with a first side surface protrusion and a second side surface protrusion disposed between the first part and the second part of the bobbin portion; The lead portion of the first coil drawn from the first part of the bobbin portion to the second terminal portion engages with the lower end of the first side surface protrusion at a position equal to or higher than the lower surface of the bobbin or the upper end of the first side surface protrusion at a position equal to or lower than the upper surface of the bobbin, and then is connected to the second terminal portion; The lead portion of the second coil drawn from the second part of the bobbin portion to the first terminal portion engages with the upper end of the second side surface protrusion at a position equal to or lower than the upper surface of the bobbin or the lower end of the second side surface protrusion at a position equal to or higher than the lower surface of the bobbin, and then is connected to the first terminal portion. A coil device.

2. The coil device according to claim 1, further comprising a plate core disposed above the drum core and connecting the upper surfaces of the flange portions of the first flange portion and the second flange portion.

3. One of the plurality of first terminal portions, which is a first terminal portion connected to the lead portion of the second coil, is disposed closer to the second side surface of the bobbin than the first side surface of the bobbin; The coil device according to claim 1, wherein a first coil connection second terminal portion, which is one of the plurality of second terminal portions and to which a lead portion of the first coil is connected, is disposed closer to the first side surface of the bobbin than the second side surface of the bobbin.

4. The lead portion of the first coil is engaged with a lower end of the first side surface protrusion located at a position higher than the lower surface of the bobbin and then connected to the second terminal portion. The coil device according to claim 1, wherein the lead portion of the second coil is engaged with an upper end of the second side surface protrusion located at a position lower than the upper surface of the bobbin and then connected to the first terminal portion.

5. The coil device according to claim 1, wherein the number of turns of the second coil wound around the second portion of the bobbin portion is the same as the number of turns of the first coil wound around the first portion of the bobbin portion.

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