JP7786239B2 - Coil parts - Google Patents

Description

The present invention relates to a coil component .

Coil components are passive elements that utilize inductance, and in recent years have been installed in a variety of electronic devices as part of the circuit elements. For example, inverters installed in vehicles such as electric vehicles, hybrid vehicles, and fuel cell vehicles incorporate converters that step up or down the battery voltage, and coil components are used as key components in these converters.

Patent Document 1 discloses one such coil component, which has a coil, a core covering the coil, and a case housing the core, with a resin gap member inside the core made of a material with a lower magnetic permeability than the core. In this coil component, the resin gap member is formed so that the distance the closed magnetic circuit passes through the resin gap member becomes shorter the further it is from the coil. Patent Document 1 also discloses that the resin gap member is formed integrally with a resin insulating member that covers the coil winding, and that the coil component is manufactured by housing the coil formed integrally with the resin gap member in a case, and then injecting resin mixed with magnetic powder into the case and allowing it to harden.

JP 2012-146753 A

However, the coil component described in Patent Document 1 is not easy to manufacture for the following reasons. Specifically, when the coil formed integrally with the resin gap member is housed in the case, there is a possibility that the resin gap member may collide with the case and be damaged. Furthermore, because the core is formed by injecting resin mixed with magnetic powder into the case while the coil formed integrally with the resin gap member is housed in the case, it is difficult to reliably expose the tip of the resin gap member on the surface of the core.

The present invention is intended to solve the above problems, and has an object to provide a coil component that is easy to manufacture.

The coil component of the present invention comprises:
A coil covered with non-magnetic resin,
a core containing, as a main component, a resin mixed with a magnetic material, and covering at least a portion of the coil covered with the non-magnetic resin;
a gap provided in the core and extending from a surface of the core toward the nonmagnetic resin;
Equipped with
the width of the gap narrows from the surface of the core toward the non-magnetic resin,
The tip of the gap extending from the surface of the core toward the non-magnetic resin is spaced apart from the non-magnetic resin.

In the coil component of the present invention, the core has a gap extending from its surface toward the non-magnetic resin covering the coil. The width of the gap narrows as it moves from the core surface toward the non-magnetic resin, and the tip of the gap is spaced apart from the non-magnetic resin. Coil components with this configuration are easy to manufacture. For example, by placing a coil covered with non-magnetic resin in a mold with protrusions, and then pouring resin mixed with a magnetic material into the mold and allowing it to harden, it is possible to manufacture a coil component in which the core and gap are integrally formed. Furthermore, the gap formed by the mold protrusions is reliably exposed on the surface of the core.

FIG. 1 is a schematic perspective view of a coil component according to a first embodiment of the present invention. 1A is a schematic top view of the coil component, and FIG. 1B is a schematic bottom view of the coil component. FIG. 2 is a schematic front view of the coil component as viewed from the direction in which the conductor wire of the coil is drawn out. FIG. 2 is a schematic perspective view of a coil. FIG. 2 is a schematic perspective view of a coil covered with a non-magnetic resin. FIG. 10 is a schematic front view of a coil component in which a gap is provided between the surface of a non-magnetic resin and the surface of a core that face each other in a direction perpendicular to the direction of the coil winding axis, as viewed from the direction in which the coil conductor wire is pulled out. 10 is a diagram showing the relationship between the direct current flowing through the coil and the inductance when the distance between the tip of the gap and the non-magnetic resin is different. FIG. 10 is a flowchart illustrating a method for manufacturing a coil component. FIG. 2 is a schematic front view of a mold used to form a core. 10A to 10C are diagrams illustrating a manufacturing process for a coil component in which a core is housed in a case. FIG. 10 is a schematic front view of a coil component according to a second embodiment, as viewed from a direction in which a conductor wire of the coil is drawn out. 10 is a schematic bottom view of a coil component in which the gap has an annular shape when the core is viewed in the direction of the winding axis of the coil. FIG.

The following describes an embodiment of the present invention and explains its features in detail.

First Embodiment
Fig. 1 is a schematic perspective view of a coil component 100 according to a first embodiment of the present invention. Fig. 2(a) is a schematic top view of the coil component 100, and Fig. 2(b) is a schematic bottom view of the coil component 100. Fig. 3 is a schematic front view of the coil component 100 as viewed from the direction in which a conductor 11 of a coil 10 (described later) is drawn out.

The coil component 100 in the first embodiment comprises a coil 10 covered with non-magnetic resin 13, a core 20, and a gap 30.

Figure 4 is a schematic perspective view of the coil 10. Figure 5 is a schematic perspective view of the coil 10 covered with non-magnetic resin 13.

As shown in Figure 4, the coil 10 is formed by winding a conductor wire 11. In this embodiment, the conductor wire 11 is wound in a rectangular shape, and when viewed in the direction of the winding axis, the corners of the rectangularly wound conductor wire 11 are rounded. However, the shape of the wound conductor wire 11 is not limited to a rectangular shape, and it may be a circular or elliptical shape, etc.

The conductor 11 is made of a metal material such as copper, aluminum, or an alloy thereof, and its surface is coated with an enamel material such as polyamideimide or polyimide. The cross-sectional shape of the conductor 11 is, for example, circular or flat. In this embodiment, the conductor 11 is a rectangular wire with a flat cross-sectional shape and is wound flatwise. However, the rectangular wire conductor 11 may also be wound edgewise. Furthermore, the coil 10 may be edgewise wound or flatwise wound and alpha wound. In other words, the present invention is not limited by the material, cross-sectional shape, winding method, etc. of the conductor 11.

Flatwise wound coil 10 is formed by bending the short side (thickness direction) of the cross section of rectangular conductor wire 11 and winding it in a spiral shape. When the winding axis is oriented vertically, flatwise wound coil 10 has low thermal conductivity in the horizontal direction of coil component 100, but good thermal conductivity in the vertical direction.

In this embodiment, the first lead-out portion 12a and the second lead-out portion 12b, where the conductor wire 11 of the coil 10 is drawn outward, are located at the same height in the direction of the winding axis of the coil 10. Furthermore, in this embodiment, the first lead-out portion 12a and the second lead-out portion 12b of the coil 10 are each drawn out to the short side of the coil 10, where the conductor wire 11 is wound in a rectangular shape. However, the first lead-out portion 12a and the second lead-out portion 12b of the coil 10 may each be drawn out to the long side of the coil 10.

As shown in FIG. 5, the coil 10 is covered with non-magnetic resin 13. In this embodiment, the entire coil 10, except for a portion of the first lead portion 12a and the second lead portion 12b, is covered with non-magnetic resin 13. Examples of materials that can be used as the non-magnetic resin 13 include epoxy resin, silicone resin, and polyphenylene sulfide resin. The thickness of the non-magnetic resin 13 is, for example, 0.1 mm or more and 3 mm or less.

There is no particular rule regarding the molding method for the non-magnetic resin 13; methods such as injection molding, transfer molding, and sheet pressing can be used. Sheet pressing is a method in which the coil 10 is covered with non-magnetic resin 13 by sandwiching the coil 10 between multiple stacked non-magnetic resin sheets and applying pressure.

In this embodiment, the non-magnetic resin 13 contains a filler with high thermal conductivity, such as alumina. With this configuration, the thermal conductivity of the non-magnetic resin 13 is, for example, 1 W/mK or higher, and the coil 10 has good heat dissipation properties.

The core 20 covers at least a portion of the coil 10, which is covered with non-magnetic resin 13. In this embodiment, as shown in Figures 1 to 3, the entire coil 10, covered with non-magnetic resin 13, is covered by the core 20, except for the first lead portion 12a, the second lead portion 12b, and their surrounding areas.

The core 20 primarily contains a resin mixed with a magnetic substance (e.g., magnetic powder) made of a soft magnetic metal material, ferrite material, or the like. The primary component is the component with the highest content. The soft magnetic metal material is not particularly limited, and examples include various crystalline alloy powder materials such as Fe-Si alloys, Fe-Si-Al alloys, Fe-Si-Cr alloys, Fe-Al alloys, Fe-Ni alloys, and Fe-Co alloys; amorphous materials with excellent soft magnetic properties that are primarily composed of Fe; and nanocrystalline metal materials with a mixture of amorphous and nanocrystalline phases. When using such soft magnetic metal materials, it is preferable to form a coating layer made of an insulating material such as phosphate or silicone resin on the surface of the metal powder to ensure insulation.

The ferrite material is also not particularly limited, and various ferrite materials containing Fe ₂ O ₃ as the main component, such as Ni-based, Cu-Zn-based, Ni-Zn-based, Mn-Zn-based, and Ni-Cu-Zn-based, can be used.

The resin contained in the core 20 is, for example, epoxy resin. However, the resin is not limited to epoxy resin, and other types of resin, such as silicone resin or polyphenylene sulfide resin, may also be used.

A gap 30 is provided in the core 20 to suppress magnetic saturation, etc. The gap is sometimes called a magnetic gap. The gap 30 is provided between the opposing surfaces of the non-magnetic resin 13 and the core 20, extending from the surface of the core 20 toward the non-magnetic resin 13. In this embodiment, the gap 30 is provided between the surface of the core 20 and the surface of the non-magnetic resin 13 that face each other in the direction of the winding axis of the coil 10, as shown in Figures 1 to 3.

Specifically, gaps 30 are provided between the first surface 20a of the core 20, which is a surface perpendicular to the winding axis of the coil 10, and the first surface 13a of the non-magnetic resin 13, and between the second surface 20b facing the first surface 20a of the core 20 and the second surface 13b facing the first surface 13a of the non-magnetic resin 13. The first surface 13a of the non-magnetic resin 13 is located on the side of the first surface 20a of the core 20 and faces the first surface 20a of the core 20. The second surface 13b of the non-magnetic resin 13 is located on the side of the second surface 20b of the core 20 and faces the second surface 20b of the core 20.

The gap 30 is exposed on each of the first surface 20a and the second surface 20b of the core 20. In this embodiment, when the core 20 is viewed in the direction of the winding axis of the coil 10, the gap 30 has a linear shape. That is, as shown in FIG. 2(a), the gap 30 extending linearly parallel to the long sides of the rectangular coil 10 is provided between the first surface 20a of the core 20 and the first surface 13a of the non-magnetic resin 13. Also, as shown in FIG. 2(b), the gap 30 extending linearly parallel to the long sides of the rectangular coil 10 is provided between the second surface 20b of the core 20 and the second surface 13b of the non-magnetic resin 13.

In this embodiment, two gaps 30 are provided between the first surface 20a of the core 20 and the first surface 13a of the non-magnetic resin 13, and two gaps 30 are provided between the second surface 20b of the core 20 and the second surface 13b of the non-magnetic resin 13. However, a gap 30 may be provided only on one of the following: between the first surface 20a of the core 20 and the first surface 13a of the non-magnetic resin 13; or between the second surface 20b of the core 20 and the second surface 13b of the non-magnetic resin 13. Also, only one gap 30 may be provided on the first surface 20a side of the core 20, or only one gap 30 may be provided on the second surface 20b side of the core 20.

Also, as shown in Figure 6, the gap 30 may be provided between the surface of the non-magnetic resin 13 and the surface of the core 20 that face each other in a direction perpendicular to the direction of the winding axis of the coil 10.

As shown in Figure 3, the tip 30a of the gap 30 extending from the surface of the core 20 toward the non-magnetic resin 13 is separated from the non-magnetic resin 13. In other words, the gap 30 is not in contact with the non-magnetic resin 13.

As shown in FIG. 3 , the width of the gap 30 narrows from the surface of the core 20 toward the non-magnetic resin 13. That is, the width of the gap 30 is widest at the surface of the core 20 and narrowest at the tip 30a. The width of the gap 30 at the surface of the core 20 is, for example, 1 mm or more and 5 mm or less, and the width of the tip 30a of the gap 30 is, for example, 0.5 mm or more and 3 mm or less. If the distance from the surface of the core 20 is the same, the width of the gap 30 is the same at any position in a direction parallel to the long sides of the coil 10. Note that in this embodiment, the gap 30 extends linearly parallel to the long sides of the coil 10, and therefore the width of the gap 30 refers to the dimension in a direction parallel to the short sides of the coil 10.

In order to achieve a configuration in which the width of the gap 30 narrows from the surface of the core 20 toward the non-magnetic resin 13, the side surfaces 30b of the gap 30 are inclined when viewed from a direction perpendicular to the width direction of the gap 30, as shown in Figure 3. Compared to when the side surfaces of the gap 30 are not inclined, it is preferable that the gradient of the side surfaces 30b of the gap 30 is greater than 0° and approximately 3° or less. As shown in Figure 3, the gap 30 has a symmetrical shape in the width direction, and the gradient of each pair of side surfaces 30b of the gap 30 is the same.

Here, even though a gap 30 is provided, it is not desirable from the perspective of magnetic properties to have the gap 30 separate from the non-magnetic resin 13 rather than in contact with it. However, if the separation distance is small, it is possible to keep the decrease in inductance when a direct current is passed through the coil 10 within an acceptable range.

Figure 7 shows the relationship between the DC current Idc flowing through the coil 10 and the inductance (L value) when the distance D1 (hereinafter also referred to as the separation distance D1 (see Figure 3)) between the tip 30a of the gap 30 and the non-magnetic resin 13 is different. Here, the relationship between the DC current Idc flowing through the coil 10 and the inductance was investigated when the distance D1 between the tip 30a of the gap 30 and the non-magnetic resin 13 was set to 0 mm, 0.001 mm, 0.01 mm, 0.02 mm, 0.03 mm, 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.5 mm, 1 mm, 2 mm, 3.75 mm, and 7.5 mm. Here, the distance D2 (see Figure 3) between the surface of the core 20 and the non-magnetic resin 13 in the direction in which the gap 30 extends from the surface of the core 20 was 8 mm.

Table 1 shows the inductance when the DC current Idc flowing through the coil 10 is 0.001 A and the distance D1 between the tip 30a of the gap 30 and the non-magnetic resin 13 is 0 mm, taken as the reference inductance. It also shows the inductance values that differ by -30%, -20%, -10%, -5%, 5%, 10%, 20%, and 30% from the reference inductance, as well as the allowable range of the separation distance D1 at that time. For example, an inductance that differs by +10% from the reference inductance (86.08 μH) is 94.69 μH, and the allowable separation distance D1 at that time is 0.05 mm or less. In other words, if the separation distance D1 between the tip 30a of the gap 30 and the non-magnetic resin 13 is 0.05 mm or less, the inductance will be 94.69 μH or less, and the variation from the reference inductance will be 10% or less.

Table 2 shows the inductance when the distance D1 between the tip 30a of the gap 30 and the non-magnetic resin 13 is 0 mm when the DC current Idc flowing through the coil 10 is 60 A, and shows the inductance values that differ from the reference inductance by -30%, -20%, -10%, -5%, 5%, 10%, 20%, and 30%, as well as the allowable range of the separation distance D1 at that time.

Table 3 shows the inductance when the distance D1 between the tip 30a of the gap 30 and the non-magnetic resin 13 is 0 mm when the DC current Idc flowing through the coil 10 is 270 A, and shows the inductance values that differ from the reference inductance by -30%, -20%, -10%, -5%, 5%, 10%, 20%, and 30%, as well as the allowable range of the separation distance D1 at that time.

As shown in Figure 7 and Tables 1 to 3, as the distance D1 between the tip 30a of the gap 30 and the non-magnetic resin 13 increases, the initial inductance increases, and the amount of inductance decrease on the high current side also increases. As shown in Table 3, when the DC current Idc flowing through the coil 10 is a large current of 270 A, if the distance D1 between the tip 30a of the gap 30 and the non-magnetic resin 13 is 0.5 mm or less, the decrease in inductance relative to the reference inductance can be kept to within 5%. Therefore, it is preferable that the distance D1 between the tip 30a of the gap 30 and the non-magnetic resin 13 be greater than 0 mm and less than 0.5 mm.

However, depending on the size of the coil component 100, even if the separation distance D1 between the tip 30a of the gap 30 and the non-magnetic resin 13 is 0.5 mm or more, inductance may not decrease significantly when DC power is applied to the coil 10. The inventors have confirmed that if the ratio D1/D2 of the distance D1 between the tip 30a of the gap 30 and the non-magnetic resin 13 to the distance D2 between the surface of the core 20 and the non-magnetic resin 13 in the direction in which the gap 30 extends from the surface of the core 20 is 1/15 or less, the decrease in inductance when DC current is superimposed can be suppressed. Therefore, it is preferable that the ratio D1/D2 be 1/15 or less.

Similar to the core 20, the separation portion 21 between the tip 30a of the gap 30 and the non-magnetic resin 13 contains a resin containing a magnetic material. The magnetic material content of the resin in the separation portion 21 is preferably lower than the magnetic material content of the resin constituting the core 20 excluding the separation portion 21. For example, if the average particle size of the magnetic material (magnetic powder) contained in the resin used to form the core 20 by molding is larger than the separation distance D1 between the tip 30a of the gap 30 and the non-magnetic resin 13, the magnetic material content of the resin in the separation portion 21 will be lower than the magnetic material content of the resin constituting the core 20 excluding the separation portion 21. By configuring the resin in the separation portion 21 to have a lower magnetic material content than the magnetic material content of the resin constituting the core 20 excluding the separation portion 21, the magnetic permeability of the separation portion 21 is lower than in a configuration in which the magnetic material content of both resins is the same, thereby further suppressing the decrease in inductance when a DC current is superimposed. Note that content refers to volume content.

In this embodiment, the gap 30 is an air gap consisting of space. However, the gap 30 is not limited to an air gap. For example, the gap 30 may be made of a non-magnetic resin.

The coil component 100 of this embodiment is easy to manufacture. For example, as described below, by placing a coil 10 covered with non-magnetic resin 13 in a mold with protrusions, and then pouring resin mixed with a magnetic material into the mold and allowing it to harden, it is possible to manufacture a coil component 100 in which the core 20 and gap 30 are integrally formed. In addition, the gap 30 formed by the mold protrusions is reliably exposed on the surface of the core 20. Furthermore, when forming the gap 30 with the mold protrusions, the protrusions corresponding to the shape of the gap 30 have a shape that tapers from the base to the tip, making it easy to remove the mold.

(Method for manufacturing coil components)
A method for manufacturing the above-described coil component 100 will be described below.

Figure 8 is a flowchart illustrating a method for manufacturing the coil component 100.

In step S1, a coil 10 covered with non-magnetic resin 13 is prepared, as shown in Figure 5. To do this, the coil 10 is first fabricated by winding a conductor 11. In this embodiment, the coil 10 is fabricated by flatwise winding the conductor 11 into a rectangular shape, as shown in Figure 4.

Then, the fabricated coil 10 is covered with non-magnetic resin 13. For example, the coil 10 is covered with non-magnetic resin 13 by transfer molding. For example, a mold is prepared, the coil 10 is placed inside the mold, non-magnetic resin is poured in and allowed to harden, and the mold is then removed to obtain the coil 10 covered with non-magnetic resin 13. For example, a mold having a structure divided into a lower mold and an upper mold is prepared, and the coil 10 is sandwiched between the lower mold and the upper mold.

In step S2, which follows step S1, a mold having protrusions corresponding to the shape of the gap 30 is prepared. Figure 9 is a schematic front view of the prepared mold 40. The mold 40 consists of an upper mold 40a and a lower mold 40b that can be separated into upper and lower halves. The upper mold 40a and the lower mold 40b each have protrusions 41 that correspond to the shape of the gap 30. "Protrusions 41 that correspond to the shape of the gap 30" means that the shape of the gap 30 and the shape of the protrusions 41 are the same. In this embodiment, the upper mold 40a and the lower mold 40b each have two protrusions 41.

The protrusions 41 become thinner from the base to the tip, and when the coil 10 is placed in the mold, they have a shape that extends linearly parallel to the long sides of the coil 10. The protrusions 41 have inclined side surfaces 41a, with an angle of inclination that is, for example, greater than 0° and less than or equal to 3°. The length of the protrusions 41 is adjusted so that the protrusions 41 do not come into contact with the non-magnetic resin 13 that covers the coil 10 when the coil 10 is placed in the mold 40.

Note that step S2 may be performed before step S1, or may be performed in parallel with step S1.

In step S3, which follows step S2, the coil 10 covered with non-magnetic resin 13 is placed in the mold 40. In this process, the protrusions 41 of the mold 40 are spaced apart from the non-magnetic resin 13 covering the coil 10 placed in the mold 40. For example, after the coil 10 covered with non-magnetic resin 13 is placed in the lower mold 40b, the lower mold 40b is combined with the upper mold 40a and clamped. Clamping the mold 40 positions the coil 10 within the mold 40. At this time, because the protrusions 41 of the mold 40 are spaced apart from the non-magnetic resin 13 covering the coil 10, no load stress is applied to the protrusions 41 of the mold 40 or the coil 10 when the mold 40 is clamped. Therefore, damage to the protrusions 41 of the mold 40 and the coil 10 can be suppressed when the mold 40 is clamped.

In step S4, which follows step S3, resin mixed with magnetic material is poured into the mold 40. This allows the resin to fill the separation portion 21 as well. If a thermosetting resin is used as the resin poured into the mold 40, it is possible to use, for example, epoxy resin or phenolic resin. If a thermoplastic resin is used, it is possible to use, for example, polyphenylene sulfide resin or polybutylene terephthalate resin. When using a thermosetting resin, it is common to use transfer molding or compression molding, and when using a thermoplastic resin, it is common to use injection molding.

In step S5, which follows step S4, the resin poured into the mold 40 is hardened. If a thermosetting resin is used, the resin is hardened by heating, and if a thermoplastic resin is used, the resin is hardened by cooling.

In step S6, which follows step S5, the mold 40 is removed after the resin has hardened. This forms the core 20 that covers the coil 10, which is covered with non-magnetic resin 13. The protrusions 41 of the mold 40 become thinner from the base to the tip, making it easier to remove the mold 40 and less likely to be damaged when removing the mold 40. By removing the mold 40, the areas where the protrusions 41 were located become hollow, forming gaps 30.

The coil component 100 is manufactured using the manufacturing method described above.

After forming the core 20, the entire core may be housed in a case. In this case, as shown in Figure 10(a), the formed core 20 is housed in a case 50. The case 50 is made of a non-magnetic metal material with high thermal conductivity, such as aluminum.

Next, as shown in Figure 10(b), potting resin 60 is injected between the core 20 and the case 50. The potting resin 60 is made of a non-magnetic resin, such as silicone resin. However, the potting resin 60 is not limited to silicone resin; epoxy resin, urethane resin, etc. may also be used.

In this embodiment, the case 50 is provided with an injection port 51 for injecting the potting resin 60, and the potting resin 60 is injected through the injection port 51. The potting resin 60 is injected, for example, to a position that covers the first surface 20a of the core 20. The injected potting resin 60 is then cured.

In this case, the potting resin 60 fills the air gap formed by the protrusion 41 of the mold 40, forming the gap 30.

Next, as shown in Figure 10(c), a lid 52 is attached to the case 50 and secured in place using screws 53. In this case, the entire assembly including the case 50 becomes the coil component 100, as shown in Figure 10(c).

The coil component manufacturing method of this embodiment facilitates manufacturing compared to conventional manufacturing methods in which a gap is formed when the coil is covered with nonmagnetic resin. Specifically, in conventional manufacturing methods in which a gap is formed when the coil is covered with nonmagnetic resin, the gap may be damaged when the coil, which is integrally formed with the gap, is placed in a case for forming the core. In contrast, in the coil component manufacturing method of this embodiment, the core 20 and gap 30 are integrally formed, eliminating such damage. Furthermore, because the gap 30 is formed by the protrusion 41 of the mold 40, the gap 30 can be reliably exposed on the surface of the core 20. Furthermore, during the process of placing the coil 10, the tip of the protrusion 41 of the mold 40 is spaced from the nonmagnetic resin 13, thereby preventing damage caused by contact between the nonmagnetic resin 13 and the protrusion 41 of the mold 40. Furthermore, because the protrusion 41 of the mold 40 tapers from its base to its tip, the mold 40 is easily removed and damage to the protrusion 41 is reduced.

Second Embodiment
FIG. 11 is a schematic front view of a coil device 100A according to the second embodiment, as viewed from the direction in which the conducting wire 11 of the coil 10 is drawn out.

In the coil component 100 of the first embodiment, the tip end 30a of the gap 30 extending from the surface of the core 20 toward the non-magnetic resin 13 is spaced apart from the non-magnetic resin 13.

In contrast, the coil component 100A of the second embodiment is configured to further include an elastic member 70 in the separation portion 21 of the coil component 100 of the first embodiment described above, sandwiched between the tip end 30a of the gap 30 and the non-magnetic resin 13. The width of the gap 30 narrows from the surface of the core 20 toward the elastic member 70.

The elastic member 70 is a non-magnetic material with a lower elastic modulus than the non-magnetic resin 13 that covers the coil 10. The elastic modulus of the elastic member 70 is, for example, 1 GPa or less. As shown in FIG. 11 , the elastic member 70 is in contact with both the gap 30 and the non-magnetic resin 13. The elastic member 70 is made of, for example, one of silicone resin, Teflon (registered trademark) resin, fluororesin, epoxy resin, and urethane resin. Because the interior of the mold 40 is exposed to high temperatures when molding the core 20, it is preferable that the elastic member 70 have excellent heat resistance. Examples of materials for the elastic member 70 that have excellent heat resistance include silicone resin, Teflon (registered trademark) resin, and fluororesin. However, the elastic member 70 is not limited to resin.

The elastic member 70 may be a type in which a liquid material is applied and then hardened, or a type in which a solid tape-like material is attached.

In this embodiment, similar to the gap 30, two elastic members 70 extending linearly parallel to the long sides of the rectangular coil 10 are provided on the first surface 13a of the non-magnetic resin 13. In addition, two elastic members 70 extending linearly parallel to the long sides of the rectangular coil 10 are provided on the second surface 13b of the non-magnetic resin 13.

The elastic member 70 is a non-magnetic material and is positioned between the gap 30 and the non-magnetic resin 13, so it also functions as a gap. Therefore, the coil component 100A of the second embodiment can better suppress the decrease in inductance when a direct current is superimposed, compared to the coil component 100 of the first embodiment, in which a magnetic material is present between the gap 30 and the non-magnetic resin 13.

The coil component 100A of the second embodiment can be manufactured using the same manufacturing method as the coil component 100 of the first embodiment. In addition to the manufacturing process for the coil component 100 of the first embodiment, the manufacturing method for the coil component 100A of the second embodiment further includes, before the process of placing the coil 10 (step S3 in FIG. 8), a process of placing an elastic member 70 having a lower elastic modulus than the nonmagnetic resin 13 on the surface of the nonmagnetic resin 13 in a position that faces the protrusion 41 of the mold 40 when the coil 10 is placed. As a result, when the coil 10 covered with the nonmagnetic resin 13 is placed in the mold 40, the protrusion 41 of the mold 40 abuts the elastic member 70, so that no load is applied to either the mold 40 or the nonmagnetic resin 13, and resin leakage at the mold mating surfaces can be suppressed.

The present invention is not limited to the above-described embodiment, and various applications and modifications can be made within the scope of the present invention. For example, as shown in Fig. 12, when the core 20 is viewed in the direction of the winding axis of the coil 10, the gap 30 may have an annular shape. While Fig. 12 shows the second surface 20b side of the core 20, the first surface 20a side is similar.
<Additional Notes>
The technical ideas that can be understood from the above-described embodiment and modified examples will be described.
[1] A coil covered with a non-magnetic resin;
a core containing, as a main component, a resin mixed with a magnetic material, and covering at least a portion of the coil covered with the non-magnetic resin;
a gap provided in the core and extending from a surface of the core toward the nonmagnetic resin;
an elastic member having a lower elastic modulus than the non-magnetic resin, the elastic member being disposed between the non-magnetic resin and a tip end of the gap extending from a surface of the core toward the non-magnetic resin;
The coil component is characterized in that the width of the gap becomes narrower from the surface of the core toward the elastic member.
[2] A method for manufacturing a coil component including: a coil covered with a non-magnetic resin; a core containing, as a main component, a resin mixed with a magnetic material and covering at least a portion of the coil covered with the non-magnetic resin; and a gap provided in the core and extending from a surface of the core toward the non-magnetic resin,
preparing the coil covered with the non-magnetic resin;
preparing a mold having a protrusion corresponding to the shape of the gap;
placing the coil covered with the non-magnetic resin in the mold;
pouring the resin mixed with the magnetic material into the mold;
curing the resin poured into the mold;
and removing the mold after the resin has hardened.
The protrusion of the mold becomes thinner from the base to the tip,
A method for manufacturing a coil component, characterized in that, in the process of placing the coil, the tip of the protrusion and the non-magnetic resin covering the coil placed in the mold are spaced apart.

REFERENCE SIGNS LIST 10 Coil 11 Conductor 12a First lead-out portion 12b Second lead-out portion 13 Non-magnetic resin 20 Core 21 Separation portion 30 Gap 40 Mold 41 Protrusion 50 Case 60 Potting resin 70 Elastic member 100, 100A Coil component

Claims (6)

A coil covered with non-magnetic resin,
a core containing, as a main component, a resin mixed with a magnetic material, and covering at least a portion of the coil covered with the non-magnetic resin;
a gap provided in the core and extending from a surface of the core toward the non-magnetic resin;
the width of the gap narrows from the surface of the core toward the non-magnetic resin,
a tip end of the gap extending from a surface of the core toward the non-magnetic resin is spaced apart from the non-magnetic resin;
a resin containing a magnetic material is interposed in a space between the tip of the gap and the non-magnetic resin,
A coil component characterized in that the content of the magnetic material in the resin interposed in the separation portion is lower than the content of the magnetic material in the resin constituting the core excluding the separation portion . The coil component described in claim 1, characterized in that the distance between the tip of the gap and the non-magnetic resin is greater than 0 mm and less than 0.5 mm. A coil component as described in claim 1 or 2, characterized in that the ratio D1/D2 of the distance D1 between the tip of the gap and the non-magnetic resin to the distance D2 between the surface of the core and the non-magnetic resin in the direction in which the gap extends from the surface of the core is 1/15 or less. The coil component according to any one of claims 1 to 3 , characterized in that the gap is provided between opposing surfaces of the core and the non-magnetic resin in the direction of the winding axis of the coil. 5. The coil component according to claim 4 , wherein the gap has a linear shape when the core is viewed in the direction of the winding axis of the coil. 5. The coil component according to claim 4 , wherein the gap has an annular shape when the core is viewed in the direction of the winding axis of the coil.