Coil device
Patent Information
- Application Number
- JP2024106324
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-07-01
- Publication Date
- 2026-01-23
AI Technical Summary
Conventional coil devices for low-voltage, high-current applications suffer from gaps between conductors and manufacturing variations in conductor positioning, affecting coupling and performance.
The coil device incorporates a core made of metal powder and resin with a first conductor and a second conductor, where the second conductor is partially disposed within a recessed groove of the first conductor, enhancing positional accuracy and preventing magnetic material entry into gaps.
This design improves positional precision, prevents reduced coupling due to magnetic material intrusion, and enhances electromagnetic coupling between conductors, while allowing for miniaturization and robust assembly.
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Abstract
Description
[Technical Field]
[0001] The present invention relates to a coil device used as an inductor or the like for low voltage, large current applications. [Background technology]
[0002] Demand for coil devices for low-voltage, high-current applications, such as TLVR circuits, is increasing. For example, the coil device shown in Patent Document 1 has been proposed as an example of a coil device for low-voltage, high-current applications. However, conventional coil devices have problems such as gaps between the first and second conductors inside the core and manufacturing variations in the positioning of the first and second conductors. For example, if a magnetic material enters the gap between the first and second conductors, it affects the coupling between the first and second conductors (reducing the coupling coefficient). Furthermore, low positioning accuracy between the first and second conductors affects the performance of the coil device. As such, positional variations, including the presence or absence and size of the gap between the first and second conductors, can hinder the performance of coil devices. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Japanese Patent Publication No. 2022-33703 Summary of the Invention [Problem to be solved by the invention]
[0004] An object of the present invention is to provide a coil device that prevents the problem of a gap being formed between a first conductor and a second conductor, and reduces variations in the relative positions of the first conductor and the second conductor. [Means for solving the problem]
[0005] In order to achieve the above object, the coil device according to the present disclosure includes a core portion including metal powder and resin; a first conductor portion having a first coil portion located within the core portion, a first mounting portion at least a portion of which is exposed from the core portion and faces a mounting target, and a first connection portion which connects the first coil portion and the first mounting portion; a second conductor portion including a second coil portion located within the core portion, a second mounting portion at least a portion of which is exposed from the core portion and faces a mounting target, and a second connection portion which connects the second coil portion and the second mounting portion; A recessed groove is formed on the inner surface of the first coil portion along the winding direction, the second coil portion extends in the winding direction along the first coil portion inside the first coil portion, At least a portion of the second coil portion is disposed within the recessed groove of the first coil portion.
[0006] In this coil device, the second coil portion of the second conductor extends in the winding direction along the first coil portion inside the first coil portion, and at least a portion of the second coil portion is disposed in a groove formed in the inner surface of the first coil portion. By disposing at least a portion of the second coil portion in the groove, it is possible to prevent magnetic materials such as metal powder from entering the gap between the first coil portion and the second coil portion. Furthermore, since the second coil portion can be simply disposed along the recessed groove of the first coil portion during assembly, the positional accuracy of the second coil portion relative to the first coil portion is improved, preventing the formation of a gap itself and enabling the positional relationship between the first coil portion and the second coil portion to be controlled with high precision.
[0007] Also, for example, at least a portion of the second coil portion may be disposed within the recessed groove throughout the entire second coil portion in the winding direction.
[0008] The positioning state of the second coil portion within the groove may be different or constant between some parts in the winding direction and other parts, but by positioning at least a portion of the second coil portion within the groove portion throughout the winding direction of the second coil portion, it is possible to achieve a higher level of effect in preventing magnetic materials from entering the gaps and improving positional accuracy.
[0009] Furthermore, for example, an adhesive cured portion in which adhesive is cured may be disposed between the first coil portion and the second coil portion in the recessed groove.
[0010] Such a coil device can more effectively prevent the problem of magnetic material such as metal powder getting between the first coil portion and the second coil portion.
[0011] Furthermore, for example, in a cross section orthogonal to the winding direction, the first coil portion and the second coil portion may have shapes that are substantially symmetrical with respect to a common axis of symmetry.
[0012] In such a coil device, the first coil portion and the second coil portion are arranged substantially symmetrically, and therefore, it is possible to suppress variations in characteristics that occur within the range of allowable manufacturing variations.
[0013] Furthermore, for example, the second coil portion may have a shorter maximum length in the depth direction of the recessed groove than the first coil portion in a cross section orthogonal to the winding direction.
[0014] In such a coil device, the opposing area between the first coil portion and the second coil portion can be increased, thereby enhancing the coupling between the first conductor portion and the second conductor portion.
[0015] Furthermore, for example, the first connection portion may be linear, and the first coil portion and the first mounting portion may be connected in a straight line, The second connection portion may be curved, and the second mounting portion to which the second connection portion is connected may extend toward the center of the device relative to the second connection portion connected to the second coil portion.
[0016] Such a coil device is particularly effective when the difference in cross-sectional area between the first conductor portion and the second conductor portion is relatively large (for example, three times or more), and can appropriately ensure the facing area of the first mounting portion and the second mounting portion to the mounting target while achieving miniaturization.
[0017] Furthermore, for example, the first connection portion may be bent, and the first mounting portion to which the first connection portion is connected may extend toward the outside of the device relative to the first connection portion connected to the first coil portion, The second connection portion may be curved, and the second mounting portion to which the second connection portion is connected may extend toward the center of the device relative to the second connection portion connected to the second coil portion.
[0018] Such a coil device is particularly effective when the difference in cross-sectional area between the first conductor portion and the second conductor portion is relatively small (for example, less than four times), and can appropriately ensure the facing area of the first mounting portion and the second mounting portion to the mounting target while achieving miniaturization.
[0019] Furthermore, for example, the second coil portion may have a maximum length in a depth direction of the recessed groove in a cross section perpendicular to the winding direction that is equal to or greater than the maximum length of the recessed groove itself in the depth direction.
[0020] In such a coil device, the coupling coefficient between the first conductor portion and the second conductor portion can be adjusted by adjusting the amount of protrusion of the second coil portion from the recessed groove.
[0021] Furthermore, for example, the second coil portion may have a maximum length in a depth direction of the recessed groove in a cross section perpendicular to the winding direction that is shorter than a maximum length in the depth direction of the recessed groove itself.
[0022] In this type of coil device, the coupling between the first and second conductors can be enhanced by placing the entire second coil portion within the groove, and the effect of preventing magnetic material from entering the gap between the first and second coil portions can be further improved. [Brief explanation of the drawings]
[0023] [Figure 1] FIG. 1 is a perspective view of a coil device according to an embodiment of the present disclosure, viewed obliquely from below. [Figure 2] FIG. 2 is a perspective view of the coil device shown in FIG. 1, seen obliquely from above. [Figure 3] FIG. 3 is a bottom view of the coil device shown in FIG. [Figure 4] FIG. 4 is a first cross-sectional view of the coil device shown in FIG. [Figure 5] FIG. 5 is a second cross-sectional view of the coil device shown in FIG. [Figure 6] FIG. 6 is a perspective view showing a first conductor portion and a second conductor portion of the coil device shown in FIG. [Figure 7] FIG. 7 is a conceptual diagram showing a second conductor portion of the coil device shown in FIG. [Figure 8] FIG. 8 is a conceptual diagram showing a coil device according to a first modified example. [Figure 9] FIG. 9 is a conceptual diagram showing a coil device according to a second modified example. [Figure 10] FIG. 10 is a conceptual diagram showing a coil device according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION
[0024] The following describes the embodiments.
[0025] First embodiment As shown in FIGS. 1 and 2, the coil device 10 according to the embodiment has a substantially rectangular parallelepiped shape and is used as a coil device for low-voltage, high-current applications, such as a TLVR circuit. The dimensions of the coil device 10 are, for example, an X-axis width of 3.0 to 12.0 mm, a Y-axis width of 3.0 to 6.0 mm, and a Z-axis width of 3.0 to 12.0 mm. In the drawings, the X, Y, and Z axes are substantially perpendicular to one another. In this embodiment, the Z axis coincides with the height direction of the coil device 10. In the following description, the direction along each axis toward the center of a component (e.g., the center of the coil device 10) is defined as inward, and the direction away from the center is defined as outward.
[0026] As shown in FIGS. 1 to 3 , the coil device 10 includes a core 20 containing metal powder and resin, a first conductor 30, and a second conductor 40. The first conductor 30 includes two first mounting portions 32a and 32b, at least partially exposed from the core 20. The second conductor 40 includes two second mounting portions 42a and 42b, at least partially exposed from the core 20. In the coil device 10, the first conductor 30, which is disposed relatively outward, functions as a primary coil, and the second conductor 40, which is disposed relatively inward, functions as a secondary coil. However, which of the first conductor 30 and the second conductor 40 is the primary coil or the secondary coil may be appropriately changed depending on the application of the coil device 10, and the inner coil may be the primary coil and the outer coil may be the secondary coil. Details of the first conductor 30 and the second conductor 40 will be described later using FIGS. 4 to 7 .
[0027] The core portion 20 is obtained, for example, by compacting a material powder, which is a mixture of metal powder and resin, in a mold in which the first conductor portion 30 and the second conductor portion 40 are placed, as shown in Fig. 6. Examples of metal powder include, but are not limited to, Fe-Ni alloy powder, Fe-Si alloy powder, Fe-Si-Cr alloy powder, Fe-Co alloy powder, Fe-Si-Al alloy powder, and amorphous iron. Examples of resin contained in the core portion 20 include, but are not limited to, epoxy resin, phenol resin, silicone resin, and other synthetic resin.
[0028] As shown in Figures 1 to 3, the core portion 20 has a substantially rectangular parallelepiped outer shape. The outer surfaces of the core portion 20 include a core upper surface 21, a core lower surface 22, a first outer surface 23, a second outer surface 24, a third outer surface 25, and a fourth outer surface 26. As shown in Figure 1, first mounting portions 32a and 32b, which are parts of the first conductor portion 30, and second mounting portions 42a and 42b, which are parts of the second conductor portion 40, are exposed from the downward-facing core lower surface 22. Of the outer surfaces of the core portion 20, the core upper surface 21, the first outer surface 23, the second outer surface 24, the third outer surface 25, and the fourth outer surface 26, excluding the core lower surface 22, are flat surfaces.
[0029] 4 is a first cross-sectional view of the coil device 10 shown in Fig. 1, and is a cross-sectional view of the coil device 10 observed along a cross section that includes a device central axis A2 that passes through the center of the coil device 10 and is parallel to the height direction (Z-axis) and is parallel to the X-axis. As shown in Fig. 4, the first conductor portion 30 has a first coil portion 31 located within the core portion 20, first mounting portions 32a and 32b that are at least partially exposed from the core portion 20 and face the mounting target, and two first connection portions 33a and 33b that connect the first coil portion 31 to each of the first mounting portions 32a and 32b.
[0030] Fig. 6 is a schematic perspective view showing the first conductor portion 30 and the second conductor portion 40 of the coil device 10 shown in Fig. 1 to Fig. 3. As shown in Fig. 6, the first conductor portion 30 and the second conductor portion 40 in the core portion 20 are present in an assembled state with each other, with a portion of the second conductor portion 40 being disposed in a recessed groove 31aa formed in the inner surface 31a of the first coil portion 31 in the first conductor portion 30.
[0031] 4 and 6, the first conductor 30 has a rectangular wave shape that protrudes upward when viewed in the Y-axis direction. The first conductor 30 can be made, for example, by machining a metal rod or a rectangular wire, but the manufacturing method of the first conductor 30 is not particularly limited. The material of the first conductor 30 can be good conductor metals such as copper, iron, gold, silver, aluminum, and alloys thereof, but is not particularly limited as long as it functions as a current path for the coil device 10.
[0032] 4 and 6, an insulating coating such as resin may be formed on the surface of the first conductor 30. Note that electrical insulation is ensured at the contact portion between the first conductor 30 and the second conductor 40 shown in Fig. 6 by the insulating coating on the surface of the first conductor 30 or the second conductor 40 or by a cured adhesive portion described later. Note that the insulating coating of the first conductor 30 is not formed on the lower surfaces of the first mounting portions 32a and 32b.
[0033] 4 and 6, the two first mounting portions 32a, 32b of the first conductor portion 30 are disposed at one end and the other end in the Y-axis direction of the first conductor portion 30. The single first coil portion 31 of the first conductor portion 30 is disposed in the center of the first conductor portion 30 in the Y-axis direction.
[0034] The first coil section 31 has a U-shaped outer shape that opens downward when viewed from the Y-axis direction, and the central part of the coil device 10 is surrounded by the first coil section 31 from three directions: from above and on both sides in the X-axis direction.
[0035] The first mounting portion 32a, which constitutes the end portion of the first conductor portion 30 on the negative X-axis direction side, is connected via a first connecting portion 33a to the end portion of the first coil portion 31 on the negative X-axis direction and downward (negative Z-axis direction). The first connecting portion 33a is bent, and the first mounting portion 32a to which the first connecting portion 33a is connected extends toward the outside D22 of the device with respect to the first connecting portion 33a which is connected to the first coil portion 31.
[0036] Meanwhile, the first mounting portion 32b constituting the end portion of the first conductor portion 30 on the positive X-axis direction side is connected via a first connecting portion 33b to the end portion of the first coil portion 31 on the positive X-axis direction and downward (negative Z-axis direction). The first connecting portion 33b is bent, and the first mounting portion 32b to which the first connecting portion 33b is connected extends toward the outside D22 of the device with respect to the first connecting portion 33b connected to the first coil portion 31. The first conductor portion 30 has a symmetrical shape with respect to the device central axis A2.
[0037] As shown in FIGS. 4 and 6, a groove 31aa is formed in the inner surface 31a of the first coil portion 31 and the first connecting portions 33a, 33b along the winding direction 62. The groove 31aa is formed to follow the shape of the first coil portion 31 in the winding direction 62, and the depth of the groove 31aa is approximately constant along the winding direction 62. The lower end of the groove 31aa continues to the inner surface of the first connecting portions 33a, 33b and extends downward. As will be described later, the second conductor portion 40 can be combined with the first conductor portion 30 as shown in FIG. 6 by being inserted into the groove 31aa from below the first conductor portion 30.
[0038] 5 is a second cross-sectional view of the coil device 10 shown in Fig. 1, and is a cross-sectional view of the coil device 10 observed along a cross section that includes a device central axis A2 that passes through the center of the coil device 10 and is parallel to the height direction (Z axis) and is parallel to the Y axis. As shown in Fig. 5, the groove 31aa has a substantially rectangular cross-sectional shape that opens to the inside, and the second coil portion 41 of the second conductor portion 40 is housed in the groove 31aa.
[0039] 1 and 6, the lower halves of the first mounting portions 32a and 32b and parts of the first connecting portions 33a and 33b are exposed downward from the core lower surface 22 of the core portion 20. By exposing not only the lower surfaces of the first mounting portions 32a and 32b but also the side surfaces of the first mounting portion 32a and parts of the first connecting portions 33a and 33b downward from the core lower surface 22 of the core portion 20, it becomes easier to form a solder fillet during mounting, and the mounting strength can be increased.
[0040] 7 is a schematic perspective view showing the external shape of the second conductor portion 40 of the coil device 10. As shown in Fig. 4 and Fig. 7, the second conductor portion 40 has a second coil portion 41 located inside the core portion 20, second mounting portions 42a and 42b at least partially exposed from the core portion 20 and facing the mounting target, and two second connection portions 43a and 43b connecting the second coil portion 41 and each of the second mounting portions 42a and 42b.
[0041] As shown in FIG. 4, the second coil portion 41 of the second conductor portion 40 extends inside the first coil portion 31 along the first coil portion 31 in the winding direction 62 while being in close contact with the inner surface 31a. As shown in FIGS. 4 and 7, the second conductor portion 40 has a rectangular ring shape (C-ring shape) with a discontinuity at the bottom when viewed from the Y-axis direction. The material and manufacturing method of the second conductor portion 40 are the same as those exemplified for the first conductor portion 30. Note that the second conductor portion 40 and the first conductor portion 30 may be made of the same material or different materials.
[0042] 4 and 7, an insulating coating such as resin may be formed on the surface of the second conductor portion 40. As with the first conductor portion 30, the insulating coating of the second conductor portion 40 is not formed on the lower surfaces of the second mounting portions 42a, 42b. Furthermore, the first coil portion 31 and the second coil portion 41 may be in close contact with each other, but there may also be a case where the first coil portion 31 and the second coil portion 41 are not in direct contact with each other, such as when an adhesive curing portion is disposed between the first coil portion 31 and the second coil portion 41 as described below.
[0043] 4, the two second mounting portions 42a, 42b of the second conductor portion 40 constitute the lower end portion (the end portion on the negative Z-axis direction side) of the second conductor portion 40. The second mounting portions 42a, 42b face each other across a discontinuous portion of the second conductor portion 40. The single second coil portion 41 of the second conductor portion 40 constitutes the portion of the second conductor portion 40 above the second mounting portions 42a, 42b and second connecting portions 43a, 43b (the portion on the positive Z-axis direction side).
[0044] Similar to the first coil section 31, the second coil section 41 has a U-shaped outer shape that opens downward when viewed in the Y direction, and the central portion of the coil device 10 is surrounded by the second coil section 41 from three directions, namely, from above and both sides in the X-axis direction. Also, as shown in Figures 4 and 6, the first coil section 31 and the second coil section 41 have a double structure along the winding direction 62, and the central portion of the coil device 10 is doubly surrounded by the first coil section 31 and the second coil section 41 from three directions, namely, from above and both sides in the X-axis direction.
[0045] The second mounting portion 42a, which is disposed on the negative X-axis side of the device central axis A2, is connected via a second connecting portion 43a to the end portion of the second coil portion 41 that is on the negative X-axis side and downward (negative Z-axis direction). The second connecting portion 43a is bent, and the second mounting portion 42a to which the second connecting portion 43a is connected extends toward the device central side D21 relative to the second connecting portion 43a that is connected to the second coil portion 41.
[0046] Meanwhile, the second mounting portion 42b of the second conductor 40, which is disposed on the positive X-axis side of the device central axis A2, is connected via a second connecting portion 43b to the end of the second coil 41 on the positive X-axis side and downward (negative Z-axis side). The second connecting portion 43b is bent, and the second mounting portion 42b to which the second connecting portion 43b is connected extends toward the device central side D21 relative to the second connecting portion 43b connected to the second coil 41. The second conductor 40 has a symmetrical shape with respect to the device central axis A2.
[0047] 4 to 6, at least a portion of second coil portion 41 is disposed in grooves 31aa of first coil portion 31 and first connecting portions 33a, 33b. As shown in Fig. 5, in a cross section orthogonal to winding direction 62 (e.g., Fig. 5), second coil portion 41 of coil device 10 has a maximum length L1 in the depth direction of groove 31aa that is the same as a maximum length L2 in the depth direction of groove 31aa itself.
[0048] That is, in the coil device 10, the cross section (e.g., FIG. 5) of the second coil portion 41 perpendicular to the winding direction 62 is rectangular, and the cross section area thereof substantially matches the cross section area of the recessed groove 31aa. However, the cross section areas of the second coil portion 41 in the cross section perpendicular to the winding direction 62 do not necessarily have to match, and the cross section area of the second coil portion 41 may be smaller or larger than the cross section area of the recessed groove 31aa (see modified examples shown in FIGS. 8 and 10).
[0049] As shown in Fig. 5, a cross section of the first coil portion 31 taken orthogonal to the winding direction 62 is substantially rectangular excluding the formation of the recessed groove 31aa. The recessed groove 31aa is formed in the center of the Y-axis direction on the inner surface 31a of the first coil portion 31. That is, in a cross section orthogonal to the winding direction 62, the first coil portion 31 and the second coil portion 41 both have substantially symmetrical shapes with respect to a common axis of symmetry (the device central axis A2 in Fig. 5). In this coil device 10, the first coil portion 31 and the second coil portion 41 are arranged substantially symmetrically, and therefore, characteristic variations occurring within the range of allowable manufacturing variations can be suppressed.
[0050] 5, an adhesive-hardened portion where the adhesive is hardened may be disposed between the first coil portion 31 and the second coil portion 41. The first coil portion 31 and the second coil portion 41 are firmly fixed to each other by the adhesive-hardened portion, which can prevent the problem of relative positional deviation between the first conductor portion 30 and the second conductor portion 40 occurring during molding of the core portion 20, etc.
[0051] 5, the second coil portion 41 has a shorter maximum length in the depth direction of the recessed groove 31aa in a cross section orthogonal to the winding direction 62 than the first coil portion 31. Because the maximum length L1 in the depth direction of the second coil portion 41 is shorter than the maximum length L3 in the depth direction of the first coil portion, the opposing area between the first coil portion 31 and the second coil portion 41 is increased, and the electromagnetic coupling between the first conductor portion 30 and the second conductor portion 40 can be improved.
[0052] As shown in Fig. 4, in the coil device 10, at least a portion of the second coil portion 41 (almost the entirety in the first embodiment, as shown in Fig. 5) is disposed within the recessed groove 31aa throughout the entire winding direction 62 of the second coil portion 41. By disposing the second coil portion 41 within the recessed groove 31aa throughout the entire winding direction 62 of the second coil portion 41, it is possible to enhance the electromagnetic coupling between the first coil portion 31 and the second coil portion 41. Furthermore, by preventing the problem of magnetic powder and the like entering the gap between the first coil portion 31 and the second coil portion 41, it is possible to more effectively prevent the problem of the coupling between the first coil portion 31 and the second coil portion 41 being reduced compared to the design value.
[0053] 1 to 7, at least a portion of the second coil portion 41 is disposed within the recessed groove 31aa, thereby preventing magnetic materials such as metal powder from entering the gap between the first coil portion 31 and the second coil portion 41 and preventing the problem of reduced coupling between the first coil portion 31 and the second coil portion 41 compared to the design value. Furthermore, since the second coil portion 41 only needs to be disposed along the recessed groove 31aa of the first coil portion 31, the positional accuracy of the second coil portion 41 relative to the first coil portion 31 is improved, preventing the occurrence of a gap itself and enabling the positional relationship between the first conductor portion 30 and the second conductor portion 40 to be managed with high accuracy.
[0054] 1 to 7 is one embodiment of a coil device according to the present disclosure, and it goes without saying that various other embodiments and modifications are included in the coil device according to the present disclosure. For example, the shapes of first mounting portions 32a, 32b and first connecting portions 33a, 33b of first conductor portion 30 shown in Fig. 6 are not limited to the example shown in Fig. 6, and the first connecting portions may be linear, and the linear first connecting portions may directly connect first coil portion 31 and the first mounting portions.
[0055] The first conductor portion having a linear first connection portion has an overall U-shaped outer shape that opens downward when viewed from the Y-axis direction, with one end face and the other end face of the first conductor portion facing downward and each end face facing the mounting target. A first conductor portion having a linear first connection portion is a preferable shape when the cross-sectional area perpendicular to the winding direction 62 of the first coil portion 31 is large (for example, the cross-sectional area is three times or more the cross-sectional area of the second coil portion 41). A first conductor portion having a linear first connection portion has a simple shape and is easy to manufacture, and because its cross-sectional area is large, the end faces of the first conductor portion can ensure the necessary facing area with respect to the mounting target.
[0056] Fig. 8 is a schematic diagram showing the shape of a coil device 110 according to a first modified example. Fig. 8(a) is a front view of the coil device 110, Fig. 8(b) is a cross-sectional view of the first coil portion 131 and the second coil portion 141 taken along a cross section perpendicular to the winding direction 62, and Fig. 8(c) is a bottom view of the first conductor portion 130 and the second conductor portion 140. Note that the front view of Fig. 8(a) shows the core portion 120 in a see-through manner, and Fig. 8(c) shows the portion that constitutes the bottom surface of the coil device 110 with diagonal hatching.
[0057] 1 to 7 in that the maximum length L1 in the depth direction of the recessed groove 131aa in the second coil portion 141 is longer than the maximum length L2 in the depth direction of the recessed groove 131aa itself. However, except for the different relationship between the maximum length L1 and the maximum length L2, the schematic structure of the coil device 110 is similar to that of the coil device 10. The description of the coil device 110 will focus on the differences from the coil device 10, and a description of the points in common with the coil device 10 will be omitted.
[0058] 8(a) and 8(b), in the coil device 110, the inner portion of the second coil portion 141 protrudes from the opening of the groove 131aa to the outside of the groove and protrudes inward from the inner surface 131a of the first coil portion 131. Even in this coil device 110, the problem of magnetic powder and the like entering the gap between the first coil portion 31 and the second coil portion 41 can be more effectively prevented than in a case where the groove 131aa is not formed. Furthermore, by inserting the second coil portion 141 into the groove 131aa, the second coil portion 141 can be assembled to the first conductor portion 130 with high precision.
[0059] As shown in FIG. 8(a), the first connection portions 133a and 133b of the first conductor portion 130 are bent, and the first mounting portions 132a and 132b extend toward the outside of the device. Furthermore, the second connection portions 143a and 143b of the second conductor portion 140 are bent, and the second mounting portions 142a and 142b extend toward the center of the device. In this coil device 110, as shown in FIG. 8(c), the distance L4 between the first mounting portions 132a and 132b constituting the bottom surface of the coil device 110 and the second mounting portions 142a and 142b constituting the bottom surface of the coil device 110 can be increased. Therefore, the coil device 110 having such a first conductor portion 130 and second conductor portion 140 can more effectively prevent short-circuiting due to reflow soldering or the like during assembly.
[0060] In addition, the coil device 110 according to the first modified example shown in FIG. 8 has the same effects as the coil device 10 in terms of the points in common with the coil device 10.
[0061] Fig. 9 is a schematic diagram showing the shape of a coil device 210 according to a second modified example. Fig. 9(a) is a front view of the coil device 210, Fig. 9(b) is a cross-sectional view of the first coil portion 31 and the second coil portion 41 taken along a cross section perpendicular to the winding direction 62, and Fig. 9(c) is a bottom view of the first conductor portion 30 and the second conductor portion 40. Note that the front view of Fig. 9(a) shows the core portion 220 in a see-through manner, and Fig. 9(c) shows the portion constituting the bottom surface of the coil device 210 with diagonal hatching.
[0062] 1 to 7, except that the thickness (length in the Y-axis direction) of the core portion 220 is different. That is, the maximum length L1 in the depth direction of the recessed groove 31aa in the second coil portion 41 is approximately equal to the maximum length L2 in the depth direction of the recessed groove 31aa itself.
[0063] In such a coil device 210, it is easier to increase the coupling coefficient K between the first conductor portion 30 and the second conductor portion 40, compared to the coil device 110 in which a portion of the second coil portion 141 protrudes from the recessed groove 31aa as shown in Fig. 8. Furthermore, since there are fewer irregularities on the surface of the assembly in which the first conductor portion 30 and the second conductor portion 40 are combined, it is possible to realize a compact coil device 210 while suppressing the electrical resistance value. Furthermore, the coil device 210 exhibits the same effects as the coil device 10.
[0064] Fig. 10 is a schematic diagram showing the shape of a coil device 310 according to a third modified example. Fig. 10(a) is a front view of the coil device 310, Fig. 10(b) is a cross-sectional view of the first coil portion 331 and the second coil portion 341 taken along a cross section perpendicular to the winding direction 62, and Fig. 10(c) is a bottom view of the first conductor portion 330 and the second conductor portion 340. Note that the front view of Fig. 10(a) shows the core portion 320 in a see-through manner, and Fig. 10(c) shows the portion constituting the bottom surface of the coil device 310 with diagonal hatching.
[0065] 1 to 7 in that the maximum length L1 in the depth direction of the recessed groove 331aa in the second coil portion 341 is shorter than the maximum length L2 in the depth direction of the recessed groove 331aa itself. However, except for the different relationship between the maximum length L1 and the maximum length L2, the schematic structure of the coil device 310 is similar to that of the coil device 10. The description of the coil device 310 will focus on the differences from the coil device 10, and a description of the points in common with the coil device 10 will be omitted.
[0066] 10(a) and 10(b), in coil device 310, the inner surface of second coil portion 341 is disposed closer to the interior of groove 331aa than the opening of groove 331aa, and is recessed into groove 331aa from inner surface 331a of first coil portion 331. This coil device 310 also effectively prevents the problem of magnetic powder and the like entering the gap between first coil portion 331 and second coil portion 341 housed inside groove 331aa. Furthermore, by inserting second coil portion 341 into groove 331aa, second conductor portion 340 can be assembled to first conductor portion 330 with high precision.
[0067] As shown in Fig. 10(c), the first mounting portions 332a, 332b, the first connecting portions 333a, 333b, the second mounting portions 342a, 342b, and the second connecting portions 343a, 343b are substantially the same as those of the second modified example shown in Fig. 10(b). In addition, the coil device 310 according to the first modified example shown in Fig. 10 has similarities with the coil device 10 and exhibits the same effects as the coil device 10. [Explanation of symbols]
[0068] 10, 110, 210, 310... Coil device 20, 120, 220, 320...Core part 21...Core top surface 22...underside of core 23...First outer surface 24…Second outer surface 25...Third outer surface 26...4th outer surface D21…Device center side D22...Outside of the device A2…Device center axis 30, 130, 330...First conductor section 31, 131, 331...First coil section 31a, 131a, 331a...Inner side 31aa, 131aa, 331aa...concave groove 62...winding direction 32a, 32b, 132a, 132b, 332a, 332b...First mounting section 33a, 33b, 133a, 133b, 333a, 333b...first connection portion 40, 140, 240, 340...Second conductor section 41, 141, 241, 341...Second coil section 42a, 42b, 142a, 142b, 342a, 342b...Second mounting section 43a, 43b, 143a, 143b, 343a, 343b...Second connection part L1, L2, L3...length L4…Interval
Claims
1. a core portion containing metal powder and resin; a first conductor portion including a first coil portion located within the core portion, a first mounting portion at least a portion of which is exposed from the core portion and faces a mounting target, and a first connection portion which connects the first coil portion and the first mounting portion; a second conductor portion including a second coil portion located within the core portion, a second mounting portion at least a portion of which is exposed from the core portion and faces a mounting target, and a second connection portion which connects the second coil portion and the second mounting portion; A recessed groove is formed on the inner surface of the first coil portion along the winding direction, the second coil portion extends in the winding direction along the first coil portion inside the first coil portion, A coil device in which at least a portion of the second coil portion is disposed within the recessed groove of the first coil portion.
2. The coil device according to claim 1 , wherein at least a portion of the second coil portion is disposed within the recessed groove throughout the entire second coil portion in the winding direction.
3. The coil device according to claim 1 , wherein an adhesive-hardened portion, in which an adhesive is hardened, is disposed between the first coil portion and the second coil portion in the recessed groove.
4. The coil device according to claim 1 , wherein, in a cross section perpendicular to the winding direction, the first coil portion and the second coil portion have shapes that are substantially symmetrical with respect to a common axis of symmetry.
5. The coil device according to claim 1 , wherein the second coil portion has a shorter maximum length in the depth direction of the groove in a cross section perpendicular to the winding direction than the first coil portion.
6. the first connection portion is linear and connects the first coil portion and the first mounting portion in a straight line; The coil device according to claim 1 , wherein the second connection portion is bent, and the second mounting portion to which the second connection portion is connected extends toward the center of the device relative to the second connection portion connected to the second coil portion.
7. the first connection portion is bent, and the first mounting portion to which the first connection portion is connected extends toward the outside of the device with respect to the first connection portion connected to the first coil portion; The coil device according to claim 1 , wherein the second connection portion is bent, and the second mounting portion to which the second connection portion is connected extends toward the center of the device relative to the second connection portion connected to the second coil portion.
8. The coil device according to claim 1 , wherein the second coil portion has a maximum length in a depth direction of the groove in a cross section perpendicular to the winding direction that is equal to or greater than a maximum length in the depth direction of the groove itself.
9. The coil device according to claim 1 , wherein the second coil portion has a maximum length in a depth direction of the groove in a cross section perpendicular to the winding direction that is shorter than a maximum length in the depth direction of the groove itself.