Coil Device

Abstract

To provide a coil device form in a small size and with a low back.SOLUTION: A coil device 10 includes: coils 41 and 42; a winding core part 21 for arranging the coils 41 and 42; a bobbin 20 having a flange part 22a that is formed in an end part of a shaft direction of the winding core part 21 and a first upper side projection part 31 projected from the flange part 22a; and a core 50v attached to the bobbin 20. A shaft core of the winding core part 21 is arranged nearly parallel to a mounting surface. The core 50v includes a concave part 54 that is convex to a direction nearly vertical to the mounting surface, and can house the first upper side projection part 31.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a coil device used as a transformer or the like. [Background technology]

[0002] A coil device having a structure as shown in Patent Document 1 is known as a coil device used as a transformer or the like. The coil device described in Patent Document 1 has a bobbin and a core attached to the bobbin. The bobbin has a winding core portion around which a first coil and a second coil are wound, and a flange portion provided at the axial end of the winding core portion. The axis of the winding core portion is disposed approximately parallel to the mounting surface, thereby achieving a low profile of the coil device.

[0003] The lower end of the flange is bent (protrudes) outward in the axial direction and functions as a terminal block. This protrusion protrudes significantly outside the core (below the core). Therefore, in the coil device described in Patent Document 1, the length of the flange in the vertical direction increases by the amount of protrusion, making it difficult to sufficiently reduce the size and height of the coil device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-111534 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a small and low-profile coil device. [Means for solving the problem]

[0006] In order to achieve the above object, a coil device according to the present invention comprises: A coil and a bobbin having a winding core for arranging the coil, a flange formed at an axial end of the winding core, and a protrusion protruding from the flange; a core attached to the bobbin, The axis of the winding core portion is disposed approximately parallel to the mounting surface, The core has a recess that is recessed in a direction substantially perpendicular to the mounting surface and is capable of accommodating the protrusion.

[0007] In the coil device according to the present invention, a recess is formed in the core, recessed in a direction approximately perpendicular to the mounting surface. Therefore, when the core is attached to the bobbin, the protrusion is accommodated within the recess, and the protrusion does not protrude significantly outside the core. In other words, in the coil device according to the present invention, the protrusion of the protrusion can be absorbed by the recess of the core, so the vertical length of the flange does not increase by the protrusion of the protrusion. Therefore, the coil device can be sufficiently made small and low-profile. Furthermore, in the coil device according to the present invention, the axis of the winding core is arranged approximately parallel to the mounting surface, so the coil device can be made even smaller and low-profile.

[0008] Preferably, the protrusion has a bottom surface shape that conforms to the inner surface shape of the recess. With this configuration, the recess is provided with a shape that is suitable for accommodating the protrusion, or a shape that is specialized for accommodating the protrusion. Therefore, it is possible to accommodate most of the protrusion inside the recess, effectively achieving a compact and low-profile coil device.

[0009] Preferably, the core has an outer leg extending along the axial direction of the winding core on a side of the winding core, and the upper surface of the outer leg is located above the bottom of the protrusion and is exposed in a direction approximately perpendicular to the mounting surface. In this way, when the upper surface of the outer leg is exposed above the bottom of the protrusion and in a direction approximately perpendicular to the mounting surface, the protrusion does not protrude significantly from the upper surface of the outer leg, effectively achieving a compact and low-profile coil device. In addition, the vertical length of the outer leg is relatively large, thereby improving the magnetic properties of the coil device.

[0010] Preferably, the coil device has a case that houses the bobbin and core, the inside of the case is filled with a heat-dissipating resin, and the upper surfaces of the outer legs are exposed from the surface of the heat-dissipating resin filled inside the case. With this configuration, heat from the bobbin, core, etc. can be efficiently dissipated via the heat-dissipating resin. Furthermore, by ensuring that the outer legs have a sufficient vertical length so that the upper surfaces of the outer legs are exposed from the surface of the heat-dissipating resin, the magnetic properties of the coil device can be further improved.

[0011] Preferably, the core has a center leg portion disposed inside the winding core portion, a hole is formed in the outer peripheral surface of the winding core portion, and the heat dissipating resin is filled between the center leg portion and the winding core portion. With this configuration, heat from the core and the like can be efficiently dissipated via the heat dissipating resin filled between the center leg portion and the winding core portion.

[0012] Preferably, the lead-out portion of the coil passes through the recess, is led from the axial end of the winding core toward the protruding portion, and is then turned around inside the recess while being led from the protruding portion toward the axial end of the winding core. Leading and turning the lead-out portion inside the recess prevents the lead-out portion from significantly protruding outside the core, thereby achieving a low-profile coil device. Furthermore, by turning the lead-out portion from a first direction to a second direction along the axial direction of the winding core and consolidating the lead-out portions at the second-direction end of the bobbin, space for arranging the lead-out portion can be saved, thereby achieving a small and low-profile coil device. Furthermore, unnecessary or difficult routing of the lead-out portion on a mounting board can be avoided, thereby facilitating routing of the lead-out portion.

[0013] Preferably, the lead-out portions of the coil are led out from the axial end of the winding core toward the protruding portion, and the protruding portion has a guide path that reverses the lead-out direction of the lead-out portions of the coil. By guiding the lead-out portions into the guide path, the lead-out portions can be reversed from a first direction to a second direction along the axial direction of the winding core, and the lead-out portions can be consolidated at the end of the bobbin in the second direction. This saves space for arranging the lead-out portions, and ultimately makes the coil device smaller and thinner.

[0014] Preferably, the protrusion has a lower protrusion provided on the lower part of the bobbin and an upper protrusion provided on the upper part of the bobbin, the upper protrusion having the guide path, and the lower protrusion having a heat dissipation fin. With this configuration, heat from the bobbin and the like can be efficiently dissipated via the heat dissipation fin. Furthermore, since the protrusion (lower protrusion) can be housed inside the recess, it is possible to prevent the coil device from becoming larger due to the installation of the heat dissipation fin.

[0015] Preferably, the flange portion has a first flange portion formed at a first axial end of the winding core portion and a second flange portion formed at a second axial end of the winding core portion, the core has a first core and a second core combined with each other, the coil has a first coil arranged radially outward of the winding core portion and a second coil arranged radially outward of the first coil, the protrusion portion has a first protrusion portion protruding from the first flange portion and a second protrusion portion protruding from the second flange portion, and the first lead-out portion of the first coil is led out toward the second protrusion portion via the first protrusion portion, and the second lead-out portion of the second coil is led out toward the second protrusion portion without passing through the first protrusion portion.

[0016] With this configuration, the first lead portion and the second lead portion are concentrated on one axial side of the bobbin, thereby saving space for arranging the first lead portion and the second lead portion, and thereby making the coil device smaller and lower in height. Furthermore, by extending the first lead portion toward the second lead portion via the first protrusion, problems such as loosening of the first lead portion can be prevented. As a result, the first lead portion can be extended toward the second protrusion at a lower position (near the outer circumferential surface of the second coil), effectively reducing the height of the coil device.

[0017] Preferably, the first protrusion has a first guide path that reverses the direction of extension of the first lead portion of the first coil, and the second protrusion has a lead-out groove through which the first lead portion and the second lead portion pass. With this configuration, the first lead portion that is extended from the first end of the winding core toward the first protrusion can be reversed in the first guide path and extended toward the second protrusion. Furthermore, by passing the first lead portion and the second lead portion through the lead-out groove, the positions of the first lead portion and the second lead portion can be fixed, preventing contact between them.

[0018] Preferably, the first lead portion passes radially outside the second coil and is drawn from the first protruding portion toward the second protruding portion, and the passing area of the first lead portion is formed radially inward of the upper end of the outer circumferential surface of the second coil and radially inward of the side ends of the outer circumferential surface of the second coil. With this configuration, the first lead portion passes near the outer circumferential surface of the second coil. This prevents the first lead portion from significantly protruding outside the core, thereby enabling the coil device to be made low-profile.

[0019] Preferably, the first coil has a first single-layer region formed of a single layer along its radial direction and a first multi-layer region formed of multiple layers along its radial direction, and the second coil has a second single-layer region formed of a single layer along its radial direction and a second multi-layer region formed of multiple layers along its radial direction, the first single-layer region and the second single-layer region being stacked along the radial direction of the winding core at predetermined positions along the axial direction of the winding core. By stacking the first single-layer region and the second single-layer region in this manner, leakage of the first coil and the second coil can be adjusted depending on the stacking condition. This can improve the magnetic characteristics of the coil device, for example, when the coil device is used as a leakage transformer. Furthermore, by stacking the first single-layer region and the second single-layer region, the number of layers of the first coil and the second coil can be minimized, effectively achieving a small and low-profile coil device. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view of a coil device according to one embodiment of the present invention. [Figure 2] FIG. 2 is an exploded perspective view of the coil device shown in FIG. [Figure 3A] FIG. 3A is a perspective view of the bobbin shown in FIG. [Figure 3B] FIG. 3B is a perspective view of the bobbin shown in FIG. 3A as viewed from a different angle. [Figure 4A] FIG. 4A is a perspective view of the bobbin shown in FIG. 2 with the first coil wound therearound. [Figure 4B] FIG. 4B is a perspective view of the bobbin shown in FIG. 4A when a second coil is further wound around it. [Figure 5] FIG. 5 is a side view of the bobbin shown in FIG. 2 when the first coil and the second coil are wound around it. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI of the coil device shown in FIG. 1 (however, the case is not shown). [Figure 7] 7 is a cross-sectional view of the coil device shown in FIG. 1 taken along line VII-VII. [Figure 8] FIG. 8 is a side view of the coil device shown in FIG. 1 with the case omitted. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, the present invention will be described based on the embodiments shown in the drawings.

[0022] The coil device 10 according to this embodiment shown in Fig. 1 functions as a transformer, for example, and is used in power supply circuits for in-vehicle chargers and various electrical devices. In the following description, the positive Z-axis direction is referred to as the upper side, and the negative Z-axis direction is referred to as the lower side. Furthermore, the side toward the center of the coil device 10 is referred to as the inside, and the side away from the center of the coil device 10 is referred to as the outside.

[0023] As shown in Fig. 2, the coil device 10 has a first coil 41, a second coil 42, a bobbin 20, and cores 50v to 50y. One of the first coil 41 and the second coil 42 constitutes a primary coil, and the other constitutes a secondary coil. In addition to the above components, the coil device 10 also has a case 70 that houses the bobbin 20 and the cores 50v to 50y, etc. The coil device 10 is a horizontal coil device in which the axis of the bobbin 20 is disposed approximately parallel to a mounting substrate (not shown).

[0024] The case 70 is made of a metal with excellent cooling properties, such as aluminum, and has a bottom 71, a side 72, and a boss 73. An opening is formed at the top of the case 70 to accommodate the bobbin 20, etc. A fastener such as a screw is fixed to the boss 73, which allows the case 70 to be attached to a mounting board (not shown).

[0025] The interior of case 70 can accommodate components such as bobbin 20 and can be filled with potting resin 90 (FIG. 7). Potting resin 90 is a heat-dissipating resin made of silicone resin, urethane resin, epoxy resin, or the like. Potting resin 90 fills the vicinity of the opening of case 70, more specifically, up to about 70 to 80% of the height of side portion 72. The top surfaces of cores 50v and 50w (top surfaces of outer leg portions 52 or base portion 51, described below) and part of bobbin 20 are exposed from the top surface of hardened potting resin 90.

[0026] In this embodiment, heat generated in the bobbin 20 and the cores 50v to 50y, etc., can be efficiently dissipated to the outside via the case 70 and the potting resin 90, thereby improving the cooling efficiency of the coil device 10.

[0027] Cores 50v to 50y are E-shaped cores and are attached to bobbin 20. Cores 50v to 50y are formed so as to be able to be combined with one another, with cores 50v and 50w being disposed above bobbin 20 and cores 50x and 50y being disposed below bobbin 20. Note that cores 50v and 50x may be integral, and cores 50w and 50y may be integral.

[0028] The cores 50v to 50y may be made of, but are not limited to, a metal or a magnetic material such as ferrite. The cores 50v to 50y each have the same shape and include a base portion 51, a pair of outer legs 52, and a center leg portion 53.

[0029] The base portion 51 has a plate shape and a predetermined thickness in the X-axis direction. A pair of outer legs 52 and a middle leg 53 are connected to the inner surface of the base portion 51 in the X-axis direction. That is, the base portion 51 supports the outer legs 52 and the middle leg 53, which extend in the X-axis direction. The outer surface of the base portion 51 in the X-axis direction has a flat shape.

[0030] A recess 54 is formed on the outer surface of the base portion 51 in the Z-axis direction. The outer surface of the base portion 51 in the Z-axis direction is the upper surface of the base portion 51 for the cores 50v and 50w, and the lower surface of the base portion 51 for the cores 50x and 50y. That is, the recess 54 is formed on a surface (a surface that defines the outer periphery or edge of the base portion 51 and is parallel to the XY plane) that is perpendicular to the inner surface of the base portion 51 in the X-axis direction (a surface to which the outer legs 52 and the middle leg 53 are connected). The recess 54 is recessed in the Z-axis direction (a direction substantially perpendicular to the mounting surface) between the pair of outer legs 52. Note that the recess 54 may be formed to straddle the base portion 51 and the pair of outer legs 52.

[0031] The base portion 51 has a core bottom portion 510a and a pair of core tapered portions 510b and 510c. The core bottom portion 510a and the pair of core tapered portions 510b and 510c form a recess 54 having a substantially V-shape.

[0032] The core bottom 510a has a surface that is approximately parallel to the mounting surface (XY plane). The core bottom 510a and the surface (the outer surface in the Z-axis direction) of the center leg 53 are approximately flush with each other. That is, the core bottom 510a is continuously connected to the outer surface in the Z-axis direction of the center leg 53 along the X-axis direction. The outer surface in the Z-axis direction of the center leg 53 is the upper surface of the center leg 53 for the cores 50v and 50w, and is the lower surface of the center leg 53 for the cores 50x and 50y. The width in the Y-axis direction of the core bottom 510a is smaller than the width in the Y-axis direction of the center leg 53.

[0033] The pair of core tapered portions 510b and 510c are formed on one side and the other side of the core bottom portion 510a in the Y-axis direction, respectively. The core tapered portions 510b and 510c connect the core bottom portion 510a to the outer surface of the outer leg portion 52 in the Z-axis direction. The outer surface of the outer leg portion 52 in the Z-axis direction is the upper surface of the outer leg portion 52 for cores 50v and 50w, and the lower surface of the outer leg portion 52 for cores 50x and 50y. The core tapered portions 510b and 510c each have a tapered surface and are inclined at a predetermined angle with respect to the core bottom portion 510a. The width of the core tapered portions 510b and 510c in the X-axis direction is the same as the thickness of the base portion 51 in the X-axis direction.

[0034] Although details will be described later, in the cores 50v to 50y, the inner surface shape of the recess 54 corresponds to the bottom surface shape or the top surface shape of each protrusion (first upper protrusion 31, second upper protrusion 32, or lower protrusion 33 shown in FIGS. 3A and 3B) of the bobbin 20. Therefore, each protrusion of the bobbin 20 can be accommodated inside the recess 54.

[0035] The pair of outer legs 52 are formed at each end of the base portion 51 in the Y-axis direction, and protrude inward in the X-axis direction from the inner surface of the base portion 51 in the X-axis direction. The pair of outer legs 52 are each disposed on a side of the winding core portion 21 of the bobbin 20 in the Y-axis direction, and extend along the axial direction of the winding core portion 21 (X-axis direction). An outer leg curved portion 520 is formed on the inner surface of each of the pair of outer legs 52 (the surface facing the middle leg portion 53). The outer leg curved portion 520 is curved so as to fit along the outer peripheral surfaces of the first coil 41 and the second coil 42.

[0036] As shown in FIG. 7 , the curvature of the outer curved portion 520 of core 50v increases upward, while the curvature of the outer curved portion 520 of core 50x increases downward. That is, the curvature of the outer curved portion 520 increases outward in the Z-axis direction of core 50v or 50x. When core 50v and core 50x are combined, a substantially C-shaped recess is formed from the inner surface of the outer leg portion 52 of core 50v to the inner surface of the outer leg portion 52 of core 50x. Note that the outer curved portion 520 of core 50v is not formed at the upper end of the inner surface of its outer leg portion 52, and the outer curved portion 520 of core 50x is not formed at the lower end of the inner surface of its outer leg portion 52.

[0037] 3A and 3B, and is exposed in a direction substantially perpendicular to the mounting surface (Z-axis direction). That is, no member such as potting resin 90 is disposed above the top surfaces of outer legs 52, and the top surfaces of outer legs 52 are exposed from the opening of case 70 to the external space.

[0038] 2, the center leg portion 53 is formed between the pair of outer leg portions 52 along the Y-axis direction, and protrudes inward in the X-axis direction from the inner surface of the base portion 51 in the X-axis direction. The center leg portion 53 is disposed inside the winding core portion 21 of the bobbin 20. More specifically, the center leg portions 53 of the cores 50v to 50y are disposed inside the through-hole 210 of the winding core portion 21 with their tip portions abutting against each other.

[0039] A center leg curved portion 530 is formed on the outer surface of center leg portion 53 (the surface facing outer leg portion 52). Center leg curved portion 530 is curved to fit the outer peripheral surfaces of first coil 41 and second coil 42, and the curvature of center leg curved portion 530 is approximately equal to the curvature of outer leg curved portion 520. Therefore, the distance between the inner surface of outer leg portion 52 and the outer surface of center leg portion 53 is approximately constant.

[0040] As shown in FIG. 7 , when the center legs 53 of the cores 50v and 50x are combined, the cross-sectional shape of the combined center legs 53 is approximately elliptical. The ellipse of the combined center legs 53 has a long side in the Y-axis direction and a short side in the Z-axis direction. When the cross-sectional shape of the combined center legs 53 is approximately elliptical, the cross-sectional area is larger than when the cross-sectional shape is a perfect circle. This allows the outer dimensions of the first coil 41 and the second coil 42, which are disposed radially outside the combined center legs 53, to be enlarged, thereby improving the magnetic characteristics of the coil device 10. Furthermore, compared to when the cross-sectional shape is rectangular, the first coil 41 and the second coil 42 are less likely to bulge, improving the quality of the coil device 10.

[0041] The bottom surface of core 50x (similar to core 50y) is disposed on bottom 71 of case 70. The top surface of core 50v (similar to core 50w) is disposed higher than the upper end of side 72 of case 70 and is exposed through the opening of case 70. Potting resin 90 is filled in the gap between each outer leg 52 of cores 50v and 50x (similar to cores 50w and 50y) and side 72 of case 70. Potting resin 90 is also filled in the gap between each outer leg 52 of cores 50v and 50x (similar to cores 50w and 50y) and the outer peripheral surface of second coil 42. The top surface of potting resin 90 is located between the top surface of center leg 53 of core 50v (similar to core 50w) and the top surface of outer leg 52 of core 50v (similar to core 50w).

[0042] 3A, the bobbin 20 has a winding core portion 21, flange portions 22a and 22b, a first upper protrusion 31, a second upper protrusion 32, and two lower protrusions 33. In addition to the above portions, the bobbin 20 also has partition flange portions 23a to 23c, wire fixing portions 24a to 24d, engaging protrusions 25a to 25c, and gaps 26a to 26c. The bobbin 20 is made of a plastic such as PPS, PET, PBT, or LCP, or another insulating material (preferably a heat-resistant material).

[0043] The winding core 21 is made of a cylindrical body having a through hole 210. The center leg portions 53 (FIG. 2) of the cores 50v to 50y are inserted into the through hole 210. A first wire 41c and a second wire 42c (FIG. 2) are wound around the outer circumferential surface of the winding core 21 to form the first coil 41 and the second coil 42.

[0044] The first wire 41c and the second wire 42c are each made of an insulating coated wire, such as a copper wire. The first wire 41c and the second wire 42c may each be made of a solid wire or a twisted wire. The wire diameter (diameter) of the first wire 41c and the second wire 42c is preferably, for example, 1.0 to 3.0 mm. The wire diameters of the first wire 41c and the second wire 42c may be the same or different. For example, the wire diameter of the first wire 41c or the second wire 42c through which a larger current flows may be made larger than the wire diameter of the other wire.

[0045] As described above, the coil device 10 in this embodiment is a horizontal coil device. Therefore, the axis of the winding core 21 is disposed approximately parallel to the mounting surface and is approximately parallel to the X-axis direction. This reduces the height of the coil device 10, making it possible to make the coil device 10 smaller and thinner.

[0046] 4A, through holes 211 and 212 are formed at a predetermined interval along the X-axis direction in the lower part of the outer circumferential surface of winding core 21. Through holes 211 and 212 are located in the center of winding core 21 in the Y-axis direction. Through holes 211 and 212 penetrate the outer circumferential surface of winding core 21 and have openings with a substantially elliptical shape. The length of through hole 211 in the X-axis direction is shorter than the length of through hole 212 in the X-axis direction.

[0047] 3B, through holes 211 and 212 are formed at predetermined intervals along the X-axis direction in the upper part of the outer circumferential surface of winding core 21. The positions of through holes 211 and 212 formed in the upper part of the outer circumferential surface of winding core 21 correspond to the positions of through holes 211 and 212 formed in the lower part of the outer circumferential surface of winding core 21 in the Z-axis direction.

[0048] By forming communication holes 211 and 212 in the outer peripheral surface of winding core 21, potting resin 90 filled in case 70 enters the inside of winding core 21 (through hole 210) via communication holes 211 and 212. Therefore, as shown in Fig. 7, potting resin 90 is filled between each center leg 53 of cores 50v and 50x (similarly for cores 50w and 50y) and winding core 21. This allows heat from cores 50v to 50y and the like to be efficiently dissipated via potting resin 90 filled between each center leg 53 and winding core 21.

[0049] 3A, flange 22a is formed at one axial end of winding core 21, and flange 22b is formed at the other axial end of winding core 21. Flanges 22a and 22b extend circumferentially on the outer circumferential surface of winding core 21. Flanges 22a and 22b also protrude a predetermined length radially outward from the outer circumferential surface of winding core 21. The lower ends of flanges 22a and 22b (similar to partition flanges 23a to 23c) are flat, allowing bobbin 20 to be stably placed inside case 70 (see FIG. 7).

[0050] Partition flanges 23a to 23c extend circumferentially on the outer peripheral surface of winding core 21. Partition flanges 23a to 23c protrude a predetermined length radially outward from the outer peripheral surface of winding core 21. Partition flanges 23a to 23c are arranged between flanges 22a and 22b along the axial direction of winding core 21. Partition flanges 23a and 23b are arranged at a relatively wide interval along the axial direction of winding core 21, whereas partition flanges 23b and 23c are arranged at a relatively narrow interval along the axial direction of winding core 21.

[0051] 5, a portion of the second coil 42 is disposed in winding section 27a formed between flange 22a and partition flange 23a. A portion of the first coil 41 and a portion of the second coil 42 are disposed in winding section 27b formed between partition flange 23a and partition flange 23b. A portion of the first coil 41 is disposed in winding section 27c formed between partition flange 23b and partition flange 23c. A portion of the first coil 41 is disposed in winding section 27d formed between partition flange 23c and flange 22b.

[0052] 3A, gaps 26a-26c are formed in the upper portion of the outer circumferential surface of winding core 21 so as to circumferentially divide partition flanges 23a-23c, respectively. That is, partition flanges 23a-23c do not extend to the positions of gaps 26a-26c. Therefore, first coil 41 and second coil 42 can move back and forth between winding sections 27a-27d (FIG. 5).

[0053] The wire fixing portions 24a to 24c are formed at the upper ends of the partition flanges 23a to 23c. Each of the wire fixing portions 24a to 24c is located on the side (negative Y-axis direction side) of the upper ends of the partition flanges 23a to 23c from which the lead-out portion 41a of the first coil 41 (FIG. 4A) is led out. The wire fixing portion 24d is formed at the upper end of the flange 22a. The wire fixing portion 24d is located on the side (negative Y-axis direction side) of the upper end of the flange 22a from which the lead-out portion 41a of the first coil 41 is led out. As shown in FIG. 4A, the lead-out portion 41a of the first coil 41 is fixed to the wire fixing portions 24a to 24d.

[0054] As shown in Fig. 3A, the engagement protrusions 25a to 25c are formed on the upper ends of the wire-fixing portions 24a to 24c. The engagement protrusions 25a and 25b are located on the side (positive Y-axis direction) of the upper ends of the wire-fixing portions 24a and 24b from which the lead-out portions 42a and 42b (Fig. 4B) of the second coil 42 are led out. The engagement protrusion 25c is located on the side (negative Y-axis direction) of the upper end of the wire-fixing portion 24c from which the lead-out portions 41a and 41b (Fig. 4B) of the first coil 41 are led out.

[0055] As shown in Fig. 4B, the lead-out portion 42b of the second coil 42 engages with the engagement protrusion 25a, the lead-out portions 42a and 42b of the second coil 42 engage with the engagement protrusion 25b, and the lead-out portions 41a and 41b of the first coil 41 engage with the engagement protrusion 25c. This makes it possible to prevent the lead-out portions from shifting positions. Alternatively, tension can be applied to the lead-out portions to prevent them from loosening.

[0056] 3B, first upper protrusion 31 is formed at the upper end of flange 22a and protrudes outward in the X-axis direction from the outer surface (outer end surface) of flange 22a in the X-axis direction. First upper protrusion 31 is formed integrally with the outer end surface of flange 22a and has a bottom wall portion 310, a wire insertion passage 311, a side wall portion 312, a thick wall portion 313, an upper wall portion 314, and a wire turn portion 315.

[0057] The bottom wall portion 310 forms the bottom surface of the first upper protrusion 31 and has a substantially V-shape. The bottom wall portion 310 has a bottom portion 310a and a pair of tapered portions 310b and 310c. The bottom portion 310a has a surface that is substantially parallel to the mounting surface (XY plane). The pair of tapered portions 310b and 310c are formed on one side and the other side of the bottom portion 310a in the Y-axis direction, respectively. The tapered portions 310b and 310c each have a tapered surface that is inclined at a predetermined angle relative to the bottom portion 310a.

[0058] The shape of the bottom wall 310 corresponds to the inner shape of the recess 54 (FIG. 2) of the core 50v. That is, the first upper protrusion 31 has a bottom shape that conforms to the inner shape of the recess 54. Therefore, as shown in FIG. 8, the bottom 310a of the bottom wall 310 and the core bottom 510a of the recess 54 are arranged opposite each other, the tapered portion 310b of the bottom wall 310 and the core tapered portion 510b of the recess 54 are arranged opposite each other, and the tapered portion 310c of the bottom wall 310 and the core tapered portion 510c of the recess 54 are arranged opposite each other. As a result, the entire bottom wall 310 or substantially the entire first upper protrusion 31 can be accommodated inside the recess 54. Note that a portion of the bottom wall 310 or a portion of the first upper protrusion 31 may protrude outside the recess 54.

[0059] 4A, the wire insertion passage 311 is formed in approximately the center of the bottom wall portion 310 in the Y-axis direction, and extends along the axial direction of the winding core portion 21. The wire insertion passage 311 is a passage formed between the side wall portion 312 and the thick wall portion 313 (FIG. 3B), and is sandwiched between the side wall portion 312 and the thick wall portion 313. The lead-out portion 41a of the first coil 41 is inserted into the wire insertion passage 311.

[0060] The side wall portion 312 extends upward from near the bottom of the bottom wall portion 310, extending in the X-axis direction from one end of the bottom wall portion 310 to the other end in the X-axis direction. As shown in FIG. 3B , the thick wall portion 313 is formed on the opposite side of the side wall portion 312 in the Y-axis direction, with the wire insertion passage 311 sandwiched therebetween. The thick wall portion 313 is integrally formed with the outer end surface of the flange portion 22a, and is formed so as to protrude outward in the X-axis direction from the outer end surface of the flange portion 22a. Therefore, the thick wall portion 313 occupies a portion of the upper surface of the tapered portion 310c of the bottom wall portion 310 (the inner region in the X-axis direction). The outer surface of the thick wall portion 313 is curved, and a wire turn portion 315 is formed around the thick wall portion 313.

[0061] The wire turn portion 315 includes a passage (wire insertion passage 311) extending a predetermined distance along the X-axis direction and a passage (passage extending along the tapered portion 310c) extending a predetermined distance along the Y-axis direction. As shown in FIG. 4A , the lead-out portion 41a of the first coil 41 is inserted into the wire turn portion 315. When the lead-out portion 41a is inserted into the wire turn portion 315, the lead-out direction of the lead-out portion 41a is reversed from the outside to the inside in the X-axis direction. That is, the wire turn portion 315 functions as a guide path that reverses the lead-out direction of the lead-out portion 41a. Because the thick wall portion 313 has a relatively large thickness, the lead-out portion 41a is inserted into the wire turn portion 315 so as to wrap around the thick wall portion 313. This makes it easy to reverse the lead-out direction of the lead-out portion 41a, which has a large wire diameter.

[0062] 8, the wire turn portion 315 is disposed inside the recess 54 of the core 50v. Therefore, the drawing direction of the draw-out portion 41a is essentially reversed inside the recess 54 from the outside to the inside in the X-axis direction. That is, the draw-out portion 41a passes through the inside of the recess 54 (more specifically, the wire insertion passage 311) and is drawn out from one axial end of the winding core 21 toward the first upper protrusion 31. The draw-out portion 41a is then drawn out from the first upper protrusion 31 toward one axial end of the winding core 21 while being reversed inside the recess 54 (more specifically, the wire turn portion 315).

[0063] In this way, by drawing out and inverting the lead-out portion 41a inside the recess 54, it is possible to prevent the lead-out portion 41a from protruding significantly above the cores 50v and 50w, thereby reducing the height of the coil device 10. Furthermore, it is possible to avoid unnecessary or difficult routing of the lead-out portion 41a on the mounting board, thereby facilitating the routing of the lead-out portion 41a.

[0064] By guiding the lead-out portion 41a to the wire turn portion 315, the lead-out portion 41a can be concentrated at the other axial end side of the bobbin 20 (the side where the second upper protrusion 32 is arranged). That is, the lead-out portion 41a (similarly to the lead-out portion 41b) is not concentrated at one axial end side of the bobbin 20 (the side where the first upper protrusion 31 is arranged), but is concentrated at the other axial end side of the bobbin 20 together with the lead-out portions 42a and 42b. This allows for space saving for the arrangement space of the lead-out portions 41a and 41b, and ultimately makes the coil device 10 smaller and thinner.

[0065] 3B, the upper wall portion 314 is formed at the upper end of the thick wall portion 313. The upper wall portion 314 extends substantially parallel to the XY plane and is disposed above the tapered portion 310c of the bottom wall portion 310. The upper wall portion 314 is intended to prevent upward displacement of the lead-out portion 41a, through which the wire turn portion 315 is inserted.

[0066] 3A, second upper protrusion 32 is formed on the upper end of flange 22b, and protrudes outward in the X-axis direction from the outer surface (outer end surface) of flange 22b in the X-axis direction. The protruding direction of second upper protrusion 32 is opposite to the protruding direction of first upper protrusion 31. Second upper protrusion 32 is formed integrally with the outer end surface of flange 22b, and has bottom wall 320, main body 321, drawing grooves 322a to 322d, and slide hole 323.

[0067] The bottom wall portion 320 has a bottom portion 320a and a pair of tapered portions 320b and 320c. The bottom wall portion 320 has a shape corresponding to the bottom wall portion 310 of the first upper protrusion 31. That is, the bottom portion 320a has a shape corresponding to the bottom portion 310a, and the pair of tapered portions 320b and 320c have shapes corresponding to the pair of tapered portions 310b and 310c.

[0068] The shape of the bottom wall portion 320 corresponds to the shape of the inner surface of the recess 54 (FIG. 2) of the core 50w. That is, the second upper protrusion 32 has a bottom surface shape that follows the shape of the inner surface of the recess 54. Therefore, the entire bottom wall portion 320 or substantially the entire second upper protrusion 32 can be accommodated inside the recess 54. Note that a part of the bottom wall portion 320 or a part of the second upper protrusion 32 may protrude outside the recess 54.

[0069] The main body 321 has a flat, approximately rectangular parallelepiped shape and is integrally connected to the upper end of the bottom wall 320. The lead-out grooves 322a to 322d are formed on the upper surface of the main body 321, extending from one end of the main body 321 to the other end in the X-axis direction. As shown in FIG. 4B , the lead-out portion 42a of the second coil 42 is inserted into the lead-out groove 322a, the lead-out portion 42b of the second coil 42 is inserted into the lead-out groove 322b, the lead-out portion 41b of the first coil 41 is inserted into the lead-out groove 322c, and the lead-out portion 41a of the first coil 41 is inserted into the lead-out groove 322d. By passing the lead-out portions through the lead-out grooves 322a to 322d in this manner, the positions of the lead-out portions are fixed, and contact between the lead-out portions is prevented.

[0070] 3A, the sliding hole 323 is formed in approximately the center of the main body 321 in the Y-axis direction. The sliding hole 323 is located between the drawing grooves 322b and 322c and extends inward in the X-axis direction. A sliding portion 61 (FIG. 2) of the cap 60, which will be described later, can be slidably inserted into the sliding hole 323.

[0071] One of the two lower protrusions 33 is formed at the lower end of flange 22a and protrudes outward in the X-axis direction from the outer surface (outer end surface) of flange 22a in the X-axis direction. The other of the two lower protrusions 33 is formed at the lower end of flange 22b and protrudes outward in the X-axis direction from the outer surface (outer end surface) of flange 22b in the X-axis direction. Each lower protrusion 33 has an upper wall 330 and heat dissipation fins 331.

[0072] The upper wall portion 330 has an apex portion 330a and a pair of tapered portions 330b and 330c. As shown in FIG. 3B, the upper wall portion 330 has a shape corresponding to the bottom wall portion 310 of the first upper protrusion 31. Also, as shown in FIG. 3A, the upper wall portion 330 has a shape corresponding to the bottom wall portion 320 of the second upper protrusion 32. That is, the apex portion 330a has a shape corresponding to the bottom portion 310a (or the bottom portion 320a), and the pair of tapered portions 330b and 330c have shapes corresponding to the pair of tapered portions 310b and 310c (or the pair of tapered portions 320b and 320c). The bottom wall portion 310 (or the bottom wall portion 320) protrudes downward to form a downward convex shape, while the upper wall portion 330 protrudes upward to form an upward convex shape.

[0073] The shape of the upper wall portion 330 corresponds to the shape of the inner surface of the recess 54 (FIG. 2) of the core 50x (or core 50y). That is, the lower protrusion 33 has an upper surface shape that conforms to the shape of the inner surface of the recess 54. Therefore, as shown in FIG. 8, the entire upper wall portion 330 or substantially the entire lower protrusion 33 can be accommodated inside the recess 54 of the core 50x. Note that part of the upper wall portion 330 or part of the lower protrusion 33 may protrude outside the recess 54.

[0074] As shown in FIG. 3A, the heat dissipation fins 331 are provided on the back surface of the upper wall portion 330 and have concave and convex portions (fins). The heat dissipation fins 331 have the function of efficiently dissipating heat from the bobbin 20. As shown in FIG. 8, when the lower protrusion 33 is housed inside the recess 54 of the core 50x (or the core 50y), the heat dissipation fins 331 are disposed inside the recess 54. This prevents the coil device 10 from becoming larger in size due to the installation of the heat dissipation fins 331. The heat dissipation fins 331 can function as a heat dissipation means at lower cost than the potting resin 90.

[0075] 6, the first coil 41 and the second coil 42 are disposed radially outside the winding core 21. More specifically, the first coil 41 is wound around the winding sections 27b to 27d of the winding core 21, and the second coil 42 is wound around the winding sections 27a and 27b of the winding core 21.

[0076] In winding section 27b, first coil 41 is wound in one layer around the outer peripheral surface of winding core 21, and in winding sections 27c and 27d, first coil 41 is wound in two layers around the outer peripheral surface of winding core 21. That is, first coil 41 has a first single-layer region 41d formed in a single layer along its radial direction, and a first multiple-layer region 41e formed in multiple layers (two layers in this embodiment) along the radial direction.

[0077] In winding section 27a, second coil 42 is wound in two layers around the outer peripheral surface of winding core 21, and in winding section 27b, it is wound in one layer around the radial outside of first coil 41 (outer peripheral surface of first coil 41). That is, second coil 42 has second single-layer region 42d formed in a single layer along the radial direction, and second multiple-layer region 42e formed in multiple layers (two layers in this embodiment) along the radial direction.

[0078] The first single-layer region 41d and the second single-layer region 42d are arranged between the first multiple-layer region 41e and the second multiple-layer region 42e along the axial direction of the winding core 21. The number of layers in the X-axis direction of the first single-layer region 41d and the number of layers in the X-axis direction of the second single-layer region 42d are both six, with a one-to-one correspondence between the numbers of layers. The first single-layer region 41d and the second single-layer region 42d are stacked along the radial direction of the winding core 21, approximately in the center of the axial direction of the winding core 21.

[0079] By stacking the first single-layer region 41d and the second single-layer region 42d in this manner, the leakage of the first coil 41 and the second coil 42 can be adjusted depending on the degree of stacking. This can improve the magnetic characteristics of the coil device 10, for example, when the coil device 10 is used as a leakage transformer. Furthermore, by stacking the first single-layer region 41d and the second single-layer region 42d, the number of layers of the first coil 41 and the second coil 42 can be minimized, effectively reducing the size and height of the coil device 10. Note that the leakage characteristics of the coil device 10 can be adjusted by appropriately changing the number of layers in the X-axis direction of the first single-layer region 41d and the number of layers in the X-axis direction of the second single-layer region 42d.

[0080] 7, an upper portion of the outer peripheral surface of the second coil 42 is exposed to the external space from the opening of the case 70 between the pair of outer legs 52 of the core 50v (similarly for the core 50w). Although not shown in detail, an upper portion of the outer peripheral surface of the first coil 41 is also exposed to the external space from the opening of the case 70 between the pair of outer legs 52 of the core 50w.

[0081] Furthermore, a lower portion of the outer peripheral surface of the second coil 42 is disposed between a pair of outer legs 52 of the core 50x (similarly for the core 50y) so as to face the bottom 71 of the case 70. Although not shown in detail, a lower portion of the outer peripheral surface of the first coil 41 is also disposed between the pair of outer legs 52 of the core 50y so as to face the bottom 71 of the case 70. In this way, by disposing the lower portions of the outer peripheral surfaces of the first coil 41 and the second coil 42 near the bottom 71, the cooling efficiency of these coils can be improved.

[0082] As shown in FIG. 4A, the lead-out portion 41a of the first coil 41 is led out toward the second upper protruding portion 32 via the first upper protruding portion 31. More specifically, the lead-out portion 41a is led out from the winding section 27b (first single-layer region 41d) shown in FIG. 6 toward the wire insertion passage 311 of the first upper protruding portion 31 while crossing the winding section 27a. At this time, the lead-out portion 41a passes radially inside the second coil 42 (second multiple-layer region 42e) toward the wire insertion passage 311. The lead-out portion 41a also changes direction along the wire turn portion 315 and passes through the lead-out groove portion 322d of the second upper protruding portion 32 while being fixed to the wire fixing portions 24a to 24c and the engaging protrusion 25c. The lead-out portion 41a passes outside the first coil 41 and the second coil 42 in the radial direction and is led out from the first upper protrusion 31 toward the second upper protrusion 32.

[0083] In this way, by drawing out the lead-out portion 41a toward the second upper protrusion 32 via the wire turn portion 315 (or by fixing it to the thick wall portion 313 shown in FIG. 3B), it is possible to prevent problems such as loosening of the lead-out portion 41a. As a result, it becomes possible to draw out the lead-out portion 41a toward the second upper protrusion 32 at a low position (near the outer circumferential surface of the first coil 41 or the second coil 42), and the height of the coil device 10 can be effectively reduced.

[0084] Furthermore, the lead-out portion 41b of the first coil 41 is led out toward the second upper protrusion 32 without passing through the first upper protrusion 31. More specifically, the lead-out portion 41b is led out from the winding section 27c (the second layer of the first multiple-layer region 41e) shown in FIG. 6 while being fixed to the engaging protrusion 25c. The lead-out portion 41b also passes through the lead-out groove 322c of the second upper protrusion 32 while crossing the winding section 27d shown in FIG. 6. The lead-out portion 41b passes radially outside the first coil 41 and is led out from the winding section 27c toward the second upper protrusion 32.

[0085] As shown in Fig. 4B, lead-out portions 42a and 42b of the second coil 42 are drawn toward the second upper protrusion 32 without passing through the first upper protrusion 31. More specifically, lead-out portion 42a is fixed to engagement protrusion 25b and drawn out from winding section 27b (second single-layer region 42d) shown in Fig. 6. Lead-out portion 42a also passes through lead-out groove 322a of second upper protrusion 32 while crossing winding sections 27c and 27d shown in Fig. 6. Lead-out portion 42a passes radially outside of first coil 41 and is drawn out from winding section 27b toward the second upper protrusion 32.

[0086] 6 (the second layer of the second multi-layer region 42e) while being fixed to the engaging projection 25a. The lead-out portion 42b passes through the lead-out groove 322b of the second upper protrusion 32 while crossing the winding sections 27b to 27d shown in FIG. 6. The lead-out portion 42b passes radially outside the first coil 41 and the second coil 42 and is led out from the winding section 27a toward the second upper protrusion 32.

[0087] 7, the passage area of the lead-out portion 41a toward the second upper protrusion 32 is formed radially inward of the upper end of the outer peripheral surface of the second coil 42 and radially inward of the side end in the Y-axis direction of the outer peripheral surface of the second coil 42. That is, if a line segment L1 that passes through the upper end of the outer peripheral surface of the second coil 42 and is parallel to the Y-axis and a line segment L2 that passes through the side end of the outer peripheral surface of the second coil 42 and is parallel to the Z-axis are defined, the passage area of the lead-out portion 41a is the area surrounded by the outer peripheral surface of the second coil 42 and the line segments L1 and L2. However, it is sufficient that at least a portion of the lead-out portion 41a is located inside the passage area, and a portion of the lead-out portion 41a may extend outside the line segment L1 or L2.

[0088] In this case, the lead-out portion 41a passes near the outer peripheral surface of the second coil 42. This prevents the lead-out portion 41a from significantly protruding above the core 50v (or core 50w), thereby enabling the coil device 10 to have a low profile.

[0089] As shown in FIG. 2, the cap 60 is attached to the upper part of the second upper protrusion 32 shown in FIG. 3A and prevents the lead-out portions of the first coil 41 and the second coil 42 from shifting upward. The cap 60 has a sliding portion 61 and engagement portions 62 and 63. The sliding portion 61 is slidably inserted into the sliding hole 323 of the second upper protrusion 32 shown in FIG. 3A. The engagement portions 62 and 63 respectively engage with the ends of the main body portion 321 of the second upper protrusion 32 shown in FIG. 3A in the Y-axis direction. This makes it possible to fix the cap 60 to the main body portion 321 via the sliding portion 61 and the engagement portions 62 and 63.

[0090] Next, a method for manufacturing the coil device 10 will be described. First, the components shown in FIG. 2 are prepared. Next, the first coil 41 and the second coil 42 are wound around the winding core 21 of the bobbin 20. For example, winding of the first wire 41c begins at the position of the winding section 27c shown in FIG. 6 using an α-winding method. That is, one end (side) of the first wire 41c is wound in a single layer around the outer circumferential surface of the winding core 21 from the winding section 27c toward the winding section 27b. Then, the wire is pulled out from the winding section 27b to the wire insertion passage 311 (FIG. 4A) of the first upper protrusion 31. The wire is then turned at the wire turn section 315 and pulled out to the outside of the second upper protrusion 32 in the X-axis direction.

[0091] Meanwhile, the other end (side) of the first wire 41c is wound in two layers so as to travel back and forth between the winding section 27c and the winding section 27d shown in Fig. 6. Then, the first wire 41c is pulled out from the winding section 27c to the outside of the second upper protrusion 32 in the X-axis direction (Fig. 4A).

[0092] The second wire 42c is wound, for example, by normal winding, around the outer peripheral surface of the first coil 41 or the outer peripheral surface of the winding core 21. That is, in the winding section 27b, the second wire 42c is wound in one layer around the outer peripheral surface of the first coil 41, and in the winding section 27a, the second wire 42c is wound in two layers around the outer peripheral surface of the winding core 21. One end (side) of the second wire 42c is pulled out from the winding section 27a to the outside of the second upper protrusion 32 in the X-axis direction (FIG. 4B), and the other end (side) of the second wire 42c is pulled out from the winding section 27b to the outside of the second upper protrusion 32 in the X-axis direction (FIG. 4B).

[0093] 2, terminals 80 are attached to the ends (lead portions 41a and 42b) of the first wire 41c and the ends (lead portions 42a and 42b) of the second wire 42c as needed. In addition, a cap 60 is attached to the top of the main body 321 of the second upper protrusion 32 as needed.

[0094] Next, the cores 50v to 50y are attached to the bobbin 20. If necessary, the cores 50v to 50y may be fixed to one another with an adhesive or the like.

[0095] Next, the bobbin 20 to which the cores 50v to 50y are attached is placed inside the case 70, and the inside of the case 70 is filled with potting resin 90 (see FIG. 7). In this manner, the coil device 10 shown in FIG. 1 can be manufactured.

[0096] As described above, in the coil device 10 of this embodiment, as shown in FIG. 2, the cores 50v to 50y are formed with recesses 54 recessed in a direction (Z-axis direction) substantially perpendicular to the mounting surface. Therefore, when the cores 50v to 50y are attached to the bobbin 20, the protrusions (first upper protrusion 31, second upper protrusion 32, and lower protrusion 33) are housed within the recesses 54, and the protrusions do not significantly protrude outside the Z-axis direction of the cores 50v to 50y. That is, in the coil device 10 of this embodiment, the protrusion amount (length in the Z-axis direction) of each protrusion can be absorbed by the recesses 54 of the cores 50v to 50y, so the vertical length of the flanges 22a and 22b does not increase by the protrusion amount of each protrusion. Therefore, the coil device 10 can be sufficiently made small and low-profile.

[0097] Furthermore, the recess 54 has a shape suitable for accommodating each protrusion of the bobbin 20, or a shape (tapered shape) specialized for accommodating each protrusion. Therefore, most of each protrusion can be accommodated inside the recess 54, and the coil device 10 can be effectively made smaller and thinner.

[0098] 8, the upper surface of the outer leg 52 is exposed above the bottom of the first upper protrusion 31 in a direction substantially perpendicular to the mounting surface (Z-axis direction), so the first upper protrusion 31 does not protrude significantly from the upper surface of the outer leg 52, effectively reducing the size and height of the coil device 10. Furthermore, the length of the outer leg 52 in the vertical direction is relatively large, which can improve the magnetic properties of the coil device 10.

[0099] 7, in this embodiment, the length of the outer leg portion 52 in the vertical direction is sufficiently long that the upper surface of the outer leg portion 52 is exposed from the upper surface of the potting resin 90. Therefore, the magnetic properties of the coil device 10 can be improved.

[0100] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

[0101] In the above embodiment, an example of application of the present invention to a transformer has been described, but the present invention can also be applied to other coil devices in addition to transformers.

[0102] In the above embodiment, the cores 50v and 50x (or cores 50w and 50y) shown in FIG. 2 may be configured as E-shaped cores, and the cores 50w and 50y (or cores 50v and 50x) may be configured as I-shaped cores. Alternatively, the cores 50v to 50y may be configured as U-shaped cores. Alternatively, the cores 50v and 50x (or cores 50w and 50y) may be configured as U-shaped cores, and the cores 50w and 50y (or cores 50v and 50x) may be configured as I-shaped cores.

[0103] In the above embodiment, as shown in FIG. 2, four cores 50v to 50y are attached to the bobbin 20, but two cores (a combination of core 50v and core 50x, and a combination of core 50w and core 50y) may also be attached to the bobbin 20.

[0104] In the above embodiment, the sum of the number of layers in the radial direction of the first coil 41 and the second coil 42 shown in Fig. 6 is two, but it may be three or more. However, in the winding section 27b, the number of layers in the radial direction of the first coil 41 is preferably an odd number, so that the lead-out portion 41a of the first coil 41 can be drawn toward the first upper protrusion 31. For example, in the winding section 27b, the first coil 41 made up of three layers and the second coil 42 made up of three layers may be stacked.

[0105] 2, the lead-out portions 41a and 41b of the first coil 41, together with the lead-out portions 42a and 42b of the second coil 42, are led out from one axial side of the bobbin 20. However, the lead-out portions 41a and 41b of the first coil 41 may be led out from the opposite side in the X-axis direction to the lead-out portions 42a and 42b of the second coil 42.

[0106] In the above embodiment, the lower protrusions 33 formed on the lower part of the bobbin 20 shown in Fig. 3 may be omitted. In this case, the recesses 54 of the cores 50x and 50y (Fig. 2) arranged below the coil device 10 may be omitted.

[0107] In the above embodiment, the bottom wall 310 of the first upper protrusion 31 shown in Fig. 3B has a tapered shape, but the shape of the bottom wall 310 is not limited to this and may be changed to various shapes. The same applies to the bottom wall 320 of the second upper protrusion 32 and the top wall 330 of the lower protrusion 33. In this case, the shape of the recesses 54 of the cores 50v to 50y may be changed depending on the shape of each protrusion. [Explanation of symbols]

[0108] 10...Coil device 20...Bobbin 21...Core 210...Through hole 211,212…Flow hole 22a, 22b…Tsubabe 23a~23c...Partition flange 24a to 24d: Wire fixing part 25a~25c…Engagement protrusion 26a~26c...Gap 27a~27d... Winding section 31...First upper protrusion 310...Bottom wall 310a…Bottom 310b, 310c...Tapered section 311...Wire insertion passage 312...Side wall 313...Thick wall part 314...Top wall part 315...Wire turn section 32...Second upper protrusion 320...Bottom wall 321...Main body 322a~322d...Drawer groove 323…Sliding hole 33…Lower protrusion 330…Top wall part 330a...Top 330b, 330c...Tapered section 331...heat dissipation fin 41...First coil 41a, 41b...1st drawer part 41c...First wire 41d...First single layer region 41e...First multi-layer region 42...Second coil 42a, 42b…Second drawer part 42c...Second wire 42d...Second single layer region 42e...Second multi-layer region 50v, 50w, 50x, 50y... Core 51...base part, 510a...Bottom of core 510b, 510c...Core tapered section 52...Outer leg 520...Outer leg curve 53...middle leg 530...Middle leg curve 54...recess 60...Cap 70…cases 90...Potting resin

Claims

1. A coil and a bobbin having a winding core for arranging the coil, a flange formed at an axial end of the winding core, and a protrusion protruding from the flange; a core attached to the bobbin, The axis of the winding core portion is disposed approximately parallel to the mounting surface, the core has a recess that is recessed in a direction substantially perpendicular to the mounting surface and is capable of accommodating the protrusion, the protruding portion has a bottom wall portion protruding from the flange portion, At least a portion of the bottom wall portion extends along an inner surface of the recessed portion and is inclined with respect to the mounting surface, A coil device in which, when viewed in the axial direction, the lead-out portion of the coil is drawn out obliquely along the bottom wall portion in a direction away from the bottom of the bottom wall portion.

2. The coil device according to claim 1 , wherein the protrusion has a bottom surface shape that conforms to the inner surface shape of the recess.

3. the core has an outer leg portion extending along the axial direction of the winding core portion on a side of the winding core portion, The coil device according to claim 1 or 2, wherein the upper surfaces of the outer legs are located above the bottoms of the protrusions and are exposed in a direction substantially perpendicular to the mounting surface.

4. a case that houses the bobbin and the core; The inside of the case is filled with a heat dissipating resin, The coil device according to claim 3 , wherein the upper surfaces of the outer legs are exposed from the surface of the heat dissipation resin filled inside the case.

5. the core has a center leg portion disposed inside the winding core portion, A hole is formed in the outer peripheral surface of the winding core, The coil device according to claim 4 , wherein the heat dissipating resin is filled between the center leg portion and the winding core portion.

6. The coil device according to any one of claims 1 to 5, wherein the pull-out portion of the coil passes through the inside of the recess and is pulled out from the axial end of the winding core portion toward the protruding portion, and is reversed inside the recess and pulled out from the protruding portion toward the axial end of the winding core portion.

7. the lead-out portion of the coil is drawn out from an axial end of the winding core portion toward the protruding portion, 7. The coil device according to claim 1, wherein the protrusion has a guide path that reverses the direction in which the lead-out portion of the coil is drawn out.

8. the protrusion has a lower protrusion provided on a lower part of the bobbin and an upper protrusion provided on an upper part of the bobbin, the upper protrusion has the guideway; The coil device according to claim 7 , wherein the lower protrusion has a heat dissipation fin.

9. the flange portion has a first flange portion formed at a first end portion in the axial direction of the winding core portion and a second flange portion formed at a second end portion in the axial direction of the winding core portion, The core includes a first core and a second core that are combined with each other, the coil includes a first coil disposed radially outward of the winding core portion and a second coil disposed radially outward of the first coil, the protruding portion has a first protruding portion protruding from the first flange portion and a second protruding portion protruding from the second flange portion, a first lead-out portion of the first coil is led out toward the second lead-out portion via the first protrusion portion, 9. The coil device according to claim 1, wherein a second lead-out portion of the second coil is led out toward the second protruding portion without passing through the first protruding portion.

10. the first protrusion has a first guide path that reverses the drawing direction of a first lead portion of the first coil, The coil device according to claim 9 , wherein the second protruding portion has a lead-out groove through which the first lead-out portion and the second lead-out portion pass.

11. the first lead-out portion passes radially outside the second coil and is led out from the first protruding portion toward the second protruding portion, 11. The coil device according to claim 9 or 10, wherein the passage area of the first lead-out portion is formed radially inward from the upper end of the outer peripheral surface of the second coil and radially inward from the side end of the outer peripheral surface of the second coil.

12. the first coil has a first single-layer region formed of a single layer along its radial direction, and a first multiple-layer region formed of multiple layers along its radial direction, the second coil has a second single-layer region formed of a single layer along its radial direction, and a second multiple-layer region formed of multiple layers along its radial direction, The coil device according to any one of claims 9 to 11, wherein the first single-layer region and the second single-layer region are stacked along the radial direction of the winding core at predetermined positions along the axial direction of the winding core.

13. A coil; a bobbin having a winding core for arranging the coil, a flange formed at an axial end of the winding core, and a protrusion protruding from the flange; a core attached to the bobbin, The axis of the winding core portion is disposed approximately parallel to the mounting surface, the core has a recess that is recessed in a direction substantially perpendicular to the mounting surface and is capable of accommodating the protrusion, the flange portion has a first flange portion formed at a first end portion in the axial direction of the winding core portion and a second flange portion formed at a second end portion in the axial direction of the winding core portion, The core includes a first core and a second core that are combined with each other, the coil includes a first coil disposed radially outward of the winding core portion and a second coil disposed radially outward of the first coil, the protruding portion has a first protruding portion protruding from the first flange portion and a second protruding portion protruding from the second flange portion, a first lead-out portion of the first coil is led out toward the second lead-out portion via the first protrusion portion, a second lead-out portion of the second coil is led out toward the second protruding portion without passing through the first protruding portion, the first lead-out portion passes radially outside the second coil and is led out from the first protruding portion toward the second protruding portion, A coil device in which the passing area of the first extraction portion is formed radially inward from the upper end of the outer peripheral surface of the second coil and radially inward from the side end of the outer peripheral surface of the second coil.

14. A coil; a bobbin having a winding core for arranging the coil, a flange formed at an axial end of the winding core, and a protrusion protruding from the flange; a core attached to the bobbin, The axis of the winding core portion is disposed approximately parallel to the mounting surface, the core has a recess that is recessed in a direction substantially perpendicular to the mounting surface and is capable of accommodating the protrusion, the flange portion has a first flange portion formed at a first end portion in the axial direction of the winding core portion and a second flange portion formed at a second end portion in the axial direction of the winding core portion, The core includes a first core and a second core that are combined with each other, the coil includes a first coil disposed radially outward of the winding core portion and a second coil disposed radially outward of the first coil, the protruding portion has a first protruding portion protruding from the first flange portion and a second protruding portion protruding from the second flange portion, a first lead-out portion of the first coil is led out toward the second lead-out portion via the first protrusion portion, a second lead-out portion of the second coil is led out toward the second protruding portion without passing through the first protruding portion, the first coil has a first single-layer region formed of a single layer along its radial direction, and a first multiple-layer region formed of multiple layers along its radial direction, the second coil has a second single-layer region formed of a single layer along its radial direction, and a second multiple-layer region formed of multiple layers along its radial direction, The coil device is such that the first single-layer region and the second single-layer region are stacked along the radial direction of the winding core at predetermined positions along the axial direction of the winding core.

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