Coil device

Abstract

[Problem] To provide a coil device. [Solution] A coil device according to the present disclosure comprises: a first magnetic material part containing a magnetic body and having a plate-shaped portion and a protruding portion that protrudes from the plate-shaped portion; a winding portion around which a flat wire is wound so as to surround the periphery of the protruding portion; and a second magnetic material part that contains a magnetic body and a resin, and covers at least the winding portion. In a prescribed cross section including a winding axis of the winding portion from which a wire cross-section, which is a cross section of the flat wire wound so as to surround the periphery of the protruding portion, is observed, a non-magnetic body gap, which is a gap between wires circumscribing at least one wire cross-section and does not include a magnetic body, is formed in a region covered by the second magnetic material part.

Description

Coil Device

[0001] The present invention relates to a coil device used as an inductor element or the like.

[0002] A coil device has been proposed that combines two types of core parts and winding parts with different resin and magnetic material content ratios. By using two types of core parts with different resin and magnetic material content ratios, such a coil device can relieve stress and prevent cracks from occurring.

[0003] In such a coil device, a configuration has been proposed in which a magnetic material is filled into the gaps between the cross sections of the wire in the winding portion, and such a coil device is advantageous from the viewpoint of improving inductance.

[0004] JP 2017-199734 A

[0005] However, in the coil device disclosed in Patent Document 1, there is a problem that dielectric breakdown occurs between the cross sections of each wire during a compression molding process in which a magnetic material is filled into the gaps in the windings. On the other hand, in a coil device in which a magnetic material is not filled into the gaps in the windings, although insulation between the wires is maintained, there is a problem in terms of improving inductance because there is no magnetic material in the gaps in the windings. The present disclosure has been made in consideration of such circumstances and provides a coil device that can prevent dielectric breakdown of metal wires and improve inductance.

[0006] The coil device according to the present disclosure comprises: a first magnetic material portion containing a magnetic material and having a plate-shaped portion and a protruding portion protruding from the plate-shaped portion; a winding portion in which a flat wire is wound so as to surround the periphery of the protruding portion; and a second magnetic material portion containing a magnetic material and a resin and covering at least the winding portion, wherein at a predetermined cross section including the winding axis of the winding portion at which a wire cross section, which is a cross section of the flat wire wound so as to surround the periphery of the protruding portion, is observed, a non-magnetic gap containing no magnetic material is formed in the area covered by the second magnetic material portion, the non-magnetic gap being a wire gap circumscribing at least one of the wire cross sections.

[0007] The coil device according to the present disclosure has a non-magnetic gap in the area covered by the second magnetic material portion of the winding portion that does not contain any magnetic material in contact with the outer periphery of the flat wire, thereby preventing the problem of insulation breakdown between the wire cross sections.

[0008] FIG. 1 is a partial perspective view of a coil device according to an embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view of the coil device shown in FIG. 1 taken along line II-II of FIG. 1. FIG. 3 is an enlarged cross-sectional view of the periphery of one of the windings included in the cross-section shown in FIG. 2. FIG. 4 is a diagram for explaining a modification of the present disclosure, and is a schematic enlarged cross-sectional view of the vicinity of the inter-wire gap inside the winding corresponding to the cross-section shown in FIG. 3. FIG. 5A is a diagram for explaining another modification of the present disclosure, and is an enlarged cross-sectional view of the periphery of the winding corresponding to FIG. 3. FIG. 5B is an enlarged cross-sectional view of the inter-wire gap inside the winding and the inter-wire gap at the protrusion included in the cross-section shown in FIG. 5A. FIG. 6 is a diagram for explaining a further modification of the present disclosure, and is a schematic enlarged cross-sectional view of the inter-wire gap at the corner of the first magnetic material portion.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The embodiments of the present disclosure described below are examples for explaining the present disclosure. Various components according to the embodiments of the present disclosure, such as numerical values, shapes, materials, and manufacturing processes, can be modified or changed within the scope that does not cause technical problems.

[0010] The shapes and the like shown in the drawings of this disclosure do not necessarily correspond to the actual shapes and the like, because the shapes and the like may be modified for the purpose of explanation.

[0011] Fig. 1 is a partial perspective view of a coil device 10 according to an embodiment of the present disclosure. As shown in Fig. 1, the coil device 10 has a first magnetic material portion 20, a second magnetic material portion 30, and a wire 40. The coil device 10 has a pair of terminal electrodes (not shown) connected to the wire 40. In Fig. 1, the second magnetic material portion 30 is shown in perspective with imaginary lines to facilitate understanding of the internal structure of the coil device 10.

[0012] 1 , the coil device 10 has a substantially rectangular parallelepiped outer shape. The first magnetic material portion 20 contains a magnetic substance and has a substantially rectangular flat plate-like portion 22 and a cylindrical protruding portion 24 protruding upward from the center of the plate-like portion 22. The plate-like portion 22 of the first magnetic material portion 20 is disposed near the bottom surface of the coil device 10.

[0013] The first magnetic material portion 20 is configured, for example, with a sintered core made of a magnetic material that does not contain resin, or a core containing a magnetic material and resin formed by compression molding or injection molding granules containing the magnetic material that constitutes the magnetic material and resin as a binder. The magnetic material powder is not particularly limited, but metal magnetic material powders such as sendust (Fe-Si-Al; iron-silicon-aluminum), Fe-Si-Cr (iron-silicon-chromium), permalloy (Fe-Ni), carbonyl iron-based, carbonyl Ni-based, amorphous powder, and nanocrystal powder are preferably used.

[0014] However, the magnetic powder may be ferrite magnetic powder such as Mn-Zn, Ni-Cu-Zn, etc. When the first magnetic material portion 20 includes a magnetic material and a resin, the binder resin included in the first magnetic material portion 20 is not particularly limited, but examples include epoxy resin, phenol resin, acrylic resin, polyester resin, polyimide, polyamideimide, silicone resin, and combinations thereof.

[0015] 2, the first magnetic material portion 20 functions as a core of the coil device 10 together with a second magnetic material portion 30, which will be described later. The plate-shaped portion 22 has a larger projected area when viewed from above than the protruding portion 24. The thickness of the plate-shaped portion 22 can be approximately 10 to 40% of the overall thickness of the coil device 10, but is not particularly limited thereto. The shape of the plate-shaped portion 22 is also not limited to a substantially rectangular flat plate, and may be a polygonal plate, a circular plate, an elliptical plate, or any other shape besides a rectangular flat plate.

[0016] The protruding height of the protruding portion 24 is not particularly limited, but can be about 20 to 70% of the overall thickness of the coil device 10. The outer peripheral shape of the protruding portion 24 shown in Fig. 1 is not limited to a circle, and may be a shape other than a circle, such as an ellipse or a polygon. However, from the viewpoint of winding the wire 40 in close contact with the outer periphery of the protruding portion 24, a circular or elliptical shape is preferable.

[0017] As shown in FIG. 1 , the wire 40 has a winding portion 42 that winds around the protrusion 24 and wire ends 41, 41 that are pulled out from the winding portion 42. The wire 40 is a flat wire with a substantially rectangular cross section. The winding portion 42 is formed by bending the wire 40 toward the long side of the substantially rectangular cross section and winding it in a so-called flatwise winding (crosswise winding) process. In this embodiment, as shown in FIG. 2 , the winding portion 42 is configured such that the flat wire 40 is crosswise wound in two layers in the direction of the winding axis parallel to the protrusion direction of the protrusion 24 and in four layers (four rows; the radial arrangement perpendicular to the winding axis direction may also be referred to as a "row") in the radial direction perpendicular to the winding axis direction.

[0018] However, the number of stages in the winding axis direction and the total number (number of rows) in the radial direction are not limited to these, and the wire may be wound in any number of stages and layers (number of rows). Furthermore, when the length of the wound wire is shortest relative to the outer periphery of the protruding portion 24, for example, the wire may be wound only around approximately half the circumference (within a range of 180°) of the outer periphery of the protruding portion 24.

[0019] The wire 40 is a metal wire with a substantially rectangular cross section, on whose surface an insulating coating layer is formed. The metal wire may be made of, for example, Cu, Al, Fe, Ag, Au, phosphor bronze, etc. The insulating coating layer may be made of, for example, polyurethane, polyamide-imide, polyimide, polyester, polyester-imide, polyester-nylon, etc.

[0020] The wire 40 is installed on the first magnetic material portion 20 by first forming a winding portion 42 as an air-core coil and arranging this around the protruding portion 24 on the upper surface of the plate-shaped portion 22 so that the central axis of the protruding portion 24 in the protruding direction is the winding axis 40a. However, the winding portion 42 may also be formed by directly winding the wire 40 around the winding portion 42 using a winding machine or the like. If it is desired to bring the winding portion 42 into close contact with the side surface 24a of the protruding portion and increase the winding density, the method of directly winding the wire 40 around the winding portion 42 is preferable.

[0021] 3, the winding portion 42 is disposed in a region defined by a substantially L-shaped wall formed by the plate-shaped portion upper surface 22c of the plate-shaped portion 22 and the protruding portion side surface 24a of the protruding portion 24. As described above, the winding portion 42 is configured by winding the wire 40 in two stages and four layers, and when viewed in the cross section shown in FIG. 2, the wire 40 in the one-stage, one-layer wire cross section 411 to one-stage, four-layer wire cross section 414 and the two-stage, one-layer wire cross section 421 to two-stage, four-layer wire cross section 424 can be observed, as shown in FIG.

[0022] The wires 40 are flat wires with a substantially rectangular cross section, but the corners (the four corners in the cross section) are formed in an arc shape, so that when a plurality of wires 40 are closely spaced and when they are installed in the first magnetic material portion 20 having the plate-like portion 22 and the protruding portion 24, gaps (wire gaps) are formed between the wires 40 or between the wires 40 and the first magnetic material portion 20. In this embodiment, these wire gaps are formed as non-magnetic gaps that do not contain any magnetic material.

[0023] 3 , a wire cross section 81a circumscribing the four wire cross sections is formed between the first-stage, first-layer wire cross section 411, the first-stage, second-layer wire cross section 412, the second-stage, first-layer wire cross section 421, and the second-stage, second-layer wire cross section 422. Similarly, a wire cross section 81b circumscribing the four wire cross sections is formed between the first-stage, second-layer wire cross section 412, the first-stage, third-layer wire cross section 413, the second-stage, second-layer wire cross section 422, and the second-stage, third-layer wire cross section 423, and a wire cross section 81c circumscribing the four wire cross sections is formed between the first-stage, third-layer wire cross section 413, the first-stage, fourth-layer wire cross section 414, the second-stage, third-layer wire cross section 423, and the second-stage, third-layer wire cross section 424. These wire gaps 81a to 81c circumscribing the four different wire cross sections are disposed inside the winding portion 42 and can be referred to as wire gaps within the winding portion. In this embodiment, these gaps between the wires inside the windings are formed as non-magnetic gaps that do not contain magnetic material.

[0024] A wire gap is also formed between the winding portion 42 and the plate-shaped portion 22. When the winding portion has a configuration in which a rectangular wire is wound in two or more rows in a radial direction perpendicular to the winding axis direction, a plate-shaped portion wire gap is formed between at least two different wire cross sections and the plate-shaped portion circumscribing the plate-shaped portion. Specifically, as shown in FIG. 3 , a wire gap 84a is formed between the one-stage, one-layer wire cross section 411 and the one-stage, two-layer wire cross section 412 and the plate-shaped portion 22; a wire gap 84b is formed between the one-stage, two-layer wire cross section 412 and the one-stage, three-layer wire cross section 413 and the plate-shaped portion 22; and a wire gap 84c is formed between the one-stage, three-layer wire cross section 413 and the one-stage, four-layer wire cross section 414 and the plate-shaped portion 22. These wire gaps 84a to 84c are formed between the plate-shaped portion 22 and the wire 40 of the winding portion 42 and can be referred to as a plate-shaped portion wire gap. In this embodiment, at least one of these plate-shaped portion-wire gaps is formed as a non-magnetic gap that does not contain any magnetic material.

[0025] Similarly, a gap can also be considered between the winding portion 42 and the protruding portion 24. However, in this embodiment, as described above, the winding portion 42 is manufactured in the form of an air-core coil and then installed on the first magnetic material portion 20. Therefore, a continuous gap (spacing) is formed between the winding portion 42 and the protruding portion 24 over the entire area of ​​the winding portion 42 (the entire area in the protruding direction of the protruding portion 24), and is not an enclosed space like the plate-shaped portion inter-wire gaps 84a-84c. Therefore, in this embodiment, the space between the winding portion 42 and the protruding portion 24 is considered to be different from the "inter-wire gap" described in the present disclosure. This space between the winding portion 42 and the protruding portion 24 is a space filled with the second magnetic material portion 30 and is not a non-magnetic material gap.

[0026] 1, the wire 40 has a pair of wire ends 41, 41 drawn out from both ends of the winding portion 42. Each wire end 41 is led out to the bottom surface 22b of the plate-shaped portion 22 via the side surface 22a of the plate-shaped portion 22 and connected to a terminal electrode portion (not shown) on the bottom surface 22b of the plate-shaped portion. The terminal electrode portion may be, for example, a metal terminal made of copper or a copper alloy bonded to the plate-shaped portion 22, or a baked electrode containing silver or a silver alloy, or a metal film electrode formed by plating or the like.

[0027] The wire ends 41, 41 and the terminal electrode are not limited to being connected at the bottom surface 22 b of the plate-like portion. For example, if the terminal electrode is an L-shaped plate member and a portion of it is disposed on the side surface 22 a of the plate-like portion, the wire ends 41, 41 and the terminal electrode may be connected at the bottom surface 22 b of the plate-like portion. Alternatively, a portion of the terminal electrode may be extended to the top surface 22 c of the plate-like portion, and the wire ends 41, 41 and the terminal electrode may be connected in the space above the top surface 22 c of the plate-like portion (the space sealed by the second magnetic material portion 30).

[0028] The shape of the terminal electrode portion, the manner in which it is placed relative to the first magnetic material portion 20 and the second magnetic material portion 30, and the shape and arrangement of the portion connecting to an external circuit may be determined arbitrarily.

[0029] As shown in FIG. 2 , the second magnetic material portion 30 covers at least the outer periphery of the winding portion 42 and, together with the first magnetic material portion 20, constitutes the core of the coil device 10. The second magnetic material portion 30 contains a magnetic material and a resin. Like the first magnetic material portion 20, the second magnetic material portion 30 contains a magnetic material, but the magnetic material content is lower than that of the first magnetic material portion 20. Because the second magnetic material portion 30 contains a lower magnetic material content, it can be disposed around the winding portion 42 in a fluid state during manufacturing. This allows the second magnetic material portion 30 to be tightly attached to the winding portion 42 from the outer periphery and above without any gaps. In this embodiment, the second magnetic material portion 30 also fills the gap (space) between the protrusion 24 and the winding portion 42.

[0030] The magnetic material contained in the second magnetic material portion 30 can be a metal magnetic powder or a ferrite magnetic powder similar to those exemplified as the magnetic powder contained in the first magnetic material portion 20. As with the first magnetic material portion 20, examples of the binder resin contained in the second magnetic material portion 30 include epoxy resin, phenol resin, acrylic resin, polyester resin, polyimide, polyamideimide, silicone resin, and combinations thereof.

[0031] 1 and 2, the second magnetic material portion 30 is arranged not only on the outer periphery of the winding portion 42 but also on the upper side of the winding portion 42 and on the upper side of the protruding portion 24. However, if the first magnetic material portion has a drum core shape having a pair of plate-like portions sandwiching the protruding portion, the second magnetic material portion may be arranged only in the region on the outer periphery of the winding portion 42 that is sandwiched between the plate-like portions in the vertical direction.

[0032] The second magnetic material portion 30 is manufactured by compression molding, etc. For example, the second magnetic material portion 30 can be obtained by putting an intermediate product in which a wound portion 42 of the wire 40 is provided around the protruding portion 24 of the first magnetic material portion 20, and a mixture of magnetic powder and binder resin, which are the materials for the second magnetic material portion 30, into a cavity and compressing the whole.

[0033] From the viewpoint of improving inductance, the content of the magnetic material in the second magnetic material portion 30 is preferably 50% or more, more preferably 70% or more, and even more preferably 80% or more. The content of the magnetic material in the second magnetic material portion 30 is a volume ratio, which can be determined by observing a cross section passing through the winding axis 40a using, for example, an electron microscope and analyzing the resulting image. The magnetic material contained in the second magnetic material portion 30 may be composed of two or more types of magnetic powder having different average particle sizes. In such a second magnetic material portion 30, the particle size distribution of the magnetic powder has multiple peaks and is distributed over a wide range. This makes it easier for magnetic powder with smaller particle sizes to enter, for example, the outer periphery and upper recesses of the winding portion 42, or between the protrusion 24 and the winding portion 42, making it easier to form the coil device 10 with a relatively low compression force.

[0034] As described above, in the coil device 10 of this embodiment, in a cross section including the winding axis 40a of the winding portion 42 as shown in Figure 3, wire-to-wire gaps 81a to 81c inside the winding portion and wire-to-wire gaps 84a to 84c are formed in the area covered by the second magnetic material portion 30, and these wire-to-wire gaps 81a to 81c inside the winding portion and wire-to-wire gaps 84a to 84c inside the plate-shaped portion are formed as non-magnetic gaps that do not contain magnetic material.

[0035] Here, the term "inter-wire gap" can generally be interpreted as a gap surrounded by two wire cross sections, but in the present disclosure, the above-described internal-winding-portion inter-wire gaps 81a to 81c are defined as inter-wire gaps circumscribing at least three different wire cross sections, and the plate-shaped portion inter-wire gaps 84a to 84c are defined as inter-wire gaps (plate-shaped portion inter-wire gaps) circumscribing at least two different wire cross sections and the plate-shaped portion 22. Furthermore, as will be described later as a modified example, an inter-wire gap circumscribing at least two different wire cross sections and the protrusion 24 can be defined as a protrusion-portion inter-wire gap, and an inter-wire gap circumscribing at least one wire cross section, the plate-shaped portion 22, and the protrusion 24 is defined as a corner inter-wire gap (first magnetic material portion corner inter-wire gap).

[0036] As described above, by forming non-magnetic gaps that do not contain magnetic material in the wire gaps circumscribing at least three different wire cross sections, i.e., in the wire gaps inside the winding section, it is possible to effectively prevent dielectric breakdown for wires whose outer peripheries are in contact with the non-magnetic gaps. Furthermore, even for wires whose outer peripheries are not in direct contact with the non-magnetic gaps, the non-magnetic gaps also reduce the contact between multiple wires in the cross-sectional direction for wires arranged around them. As a result, it is possible to make the contact between each wire throughout the coil device closer to a uniform state, and dielectric breakdown between the wire cross sections can be appropriately prevented.

[0037] The wire gaps 81a to 81c inside the winding portion and the wire gaps 84a to 84c in the plate-shaped portion, as well as the wire gaps in the protrusion portion and the wire gaps in the corner portions of the first magnetic material portion described below, are all considered to be gaps whose maximum length in the cross section of the wire gap is smaller than the short side of the cross section of the wire 40. The reason why the maximum cross-sectional length of the gap defining the wire gap is specified to be smaller than the short side of the wire cross section is to exclude a large circumscribing circle that circumscribes the wire cross section from the outside of the winding portion 42.

[0038] By making the gaps between the wires such a sufficiently small space (gap), it is possible to properly form non-magnetic gaps that do not contain magnetic material, thereby properly maintaining the close contact state of the multiple wires in the cross-sectional direction, and maintaining the required inductance even if there are non-magnetic gaps in the winding section.

[0039] Whether or not magnetic material is contained in the gaps between the wires 81a to 81c, 84a to 84c is determined by whether or not magnetic material powder is observed in the corresponding gaps between the wires in a microscopic cross-sectional photograph at a magnification of approximately 250 times.

[0040] In this way, in the coil device 10 of this embodiment, the wire gaps formed in the winding portion 42 (wire gaps 81a to 81c inside the winding portion) are formed as non-magnetic gaps that do not contain magnetic material, so that the problem of insulation breakdown between wire cross sections during manufacturing can be appropriately prevented.

[0041] Furthermore, in the coil device 10 according to this embodiment, the plate-shaped portion wire gaps 84a to 84c formed between the winding portion 42 and the plate-shaped portion 22 of the first magnetic material portion 20 are also formed as non-magnetic gaps that do not contain any magnetic material. The wire cross sections facing the first magnetic material portion 20 tend to be subjected to relatively strong deformation forces during the compression molding process of the second magnetic material portion 30. However, by forming the plate-shaped portion wire gaps 84a to 84c between the winding portion 42 and the plate-shaped portion 22 of the first magnetic material portion 20 as non-magnetic gaps, as in this embodiment, damage to the insulating coating and the like caused by magnetic powder can be appropriately prevented, and insulation between the wire cross sections can be suitably ensured.

[0042] In addition, in the coil device 10 according to this embodiment, by setting the content of the magnetic body in the second magnetic material portion to 50% or more, the magnetic permeability value of the second magnetic material portion can be increased, and inductance can be improved. In the coil device, since the first inter-wire region is formed in the winding portion, even if the molding pressure of the second magnetic material portion is increased to increase the content of the magnetic body, the occurrence of insulation breakdown between the wire cross sections can be suitably prevented.

[0043] Furthermore, in the coil device 10 according to the present embodiment, the winding portion is configured by flatwise winding the rectangular wire, but when the rectangular wire is tightly wound in flatwise winding, the rectangular wire is arranged in close contact in the cross-sectional direction, and the energy density per unit cross section increases, making it difficult to maintain insulation between the wires. However, even in such a configuration, the coil device according to the present disclosure has gaps between the wires in contact with the outer periphery of the rectangular wire that constitutes the winding portion in the area covered with the second magnetic material portion, so that insulation breakdown between the wire cross sections can be appropriately prevented.

[0044] The present disclosure is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

[0045] For example, in the above-described embodiment, all of the plurality of inter-wire gaps 81a-81c inside the winding portion are configured as non-magnetic gaps, and all of the plurality of inter-wire gaps 84a-84c between the plate-shaped portion are configured as non-magnetic gaps. By forming all of the inter-wire gaps inside the winding portion as non-magnetic gaps that do not contain magnetic material, the effect of preventing dielectric breakdown in the winding portion can be more effectively exerted. Furthermore, by forming all of the inter-wire gaps between the wire cross sections and the plate-shaped portion as non-magnetic gaps that do not contain magnetic material, the occurrence of dielectric breakdown between the wire cross sections can be more effectively prevented.

[0046] However, any of the inter-wire gaps 81a to 81c inside the winding portion and the inter-wire gaps 84a to 84c in the plate-shaped portion may be formed as a gap containing a magnetic material. The functions and effects of the present disclosure can be achieved as long as at least one non-magnetic space is formed in each of the inter-wire gaps 81a to 81c inside the winding portion or the inter-wire gaps 84a to 84c in the plate-shaped portion, and it is not essential that all inter-wire gaps be non-magnetic gaps.

[0047] 4, of the inter-wire gaps 81a to 81c inside the winding portion, the inter-wire gap 81c closest to the second magnetic material portion 30 may be formed as a magnetic material gap containing magnetism. By forming a part of the inter-wire gaps 81a to 81c inside the winding portion or the inter-wire gaps 84a to 84c in the plate-shaped portion as a magnetic material gap, the inductance of the coil device 10 can be improved.

[0048] The particle size (average particle size) of the magnetic material 33 (=32) contained in the magnetic material gaps in the winding portion 42 (for example, the gaps 81c between the wires in FIG. 4) is preferably smaller than the average particle size of the magnetic materials 31, 32 in the second magnetic material portion 30. Controlling the pressure when compressing and molding the second magnetic material portion 30 so that small magnetic powders selectively flow into the gaps between the wires in the winding portion 42 contributes to improving the inductance of the coil device 10 and also makes it possible to prevent dielectric breakdown between the cross sections of the wires.

[0049] For example, when at least two of the wire cross sections forming the inter-wire gaps have the long sides of the cross sections of the rectangular wire adjacent to the second magnetic material portion 30 without any other wire cross sections sandwiched between them, the inter-wire gaps (outer inter-wire gaps) may be defined as the magnetic material gaps in the winding portion 42. The inter-wire gaps defined in this way are inter-wire gaps arranged at positions where some of the magnetic material contained in the second magnetic material portion 30 can easily flow in through the gaps in the wire cross sections when the second magnetic material portion 30 is compression-molded, and are therefore suitable because they allow for selective formation of magnetic material gaps without increasing the compression molding pressure.

[0050] In the above-described embodiment, a continuous gap is formed between the winding portion 42 and the protruding portion 24 and is filled with the second magnetic material portion 30, so that the gap does not become a non-magnetic gap. However, as shown in Fig. 5A , if the winding portion 42 is formed in substantially close contact with the protruding portion 24, for example, by directly winding the wire 40 around the protruding portion 24 with a winding machine, a coil device can also be configured having a protruding-wire gap 82 as a non-magnetic gap, as shown in Fig. 5B .

[0051] That is, in a winding section having a configuration in which a flat wire is wound in two or more stages in a winding axis direction parallel to the protruding direction of the protrusion, at least one of the protrusion-wire gaps, which are wire gaps circumscribing at least two different wire cross sections and the protrusion, may be a non-magnetic gap that does not contain a magnetic material.

[0052] 5A and 5B , the protrusion-wire gap 82 is a closed gap formed between the one-stage, one-layer wire cross section 411, the two-stage, one-layer wire cross section 421, and the protrusion 24 of the first magnetic material portion, i.e., the wire gap according to the present disclosure. The protrusion-wire gap 82 is a gap into which the second magnetic material portion does not enter, that is, it is configured as a non-magnetic gap that does not contain a magnetic material. The coil device according to the present disclosure may be embodied in such a form.

[0053] In a configuration in which the rectangular wire is wound in three or more layers in the winding axis direction parallel to the protruding direction of the protrusions, multiple gaps are formed between the protrusions and the wires. In such a configuration, all of the multiple gaps between the protrusions and the wires may be non-magnetic gaps. By forming all of the gaps between the protrusions and the wires as non-magnetic gaps that do not contain magnetic material, it is possible to more effectively prevent the occurrence of insulation breakdown between the wire cross sections.

[0054] Furthermore, the wire gaps formed between the wire cross sections at the corners where the plate-like portion and the protrusion of the first magnetic material portion form a boundary, i.e., the wire gaps at the corners of the first magnetic material portion circumscribing at least one wire cross section, the plate-like portion, and the protrusion, may also be non-magnetic gaps containing no magnetic material. The wire cross sections facing the first magnetic material portion may be subjected to a relatively strong deformation force, and by arranging the non-magnetic gaps containing no magnetic material near the first magnetic material portion, it is possible to effectively prevent the occurrence of insulation breakdown between the wire cross sections.

[0055] Furthermore, the coil device according to the present disclosure is not limited to a flatwise wound coil device. For example, as shown in Fig. 6, the flat wire 40 may be wound edgewise around the protruding portion 24 of the first magnetic material portion 20.

[0056] In a configuration in which the flat wire is tightly wound edgewise, stress is easily applied to the inner edge of the flat wire, making it difficult to maintain insulation between the wires. However, even in such a configuration, the coil device according to the present disclosure has gaps between the wires in contact with the outer periphery of the flat wire that constitutes the winding portion in the area covered with the second magnetic material portion, so that insulation breakdown between the wire cross sections can be appropriately prevented.

[0057] Furthermore, the coil device according to the present disclosure is not limited to a configuration in which the flat wire 40 is wound in multiple rows and columns (multilayers). For example, as shown in Fig. 6, the flat wire 40 may be wound only once around the corner where the plate-shaped portion 22 of the first magnetic material portion 20 intersects with the protruding portion 24, or alternatively, around ¾ (270°) or ½ (180°) of a full turn. Even in such a configuration, a gap is formed at the corner between the wire 40, the plate-shaped portion 22 of the first magnetic material portion 20, and the protruding portion 24. This gap is configured as a non-magnetic gap (first magnetic material portion corner wire gap) that does not allow the second magnetic material portion to enter, thereby achieving the same effects and advantages as those of the above-described embodiment.

[0058] This specification discloses the following:

[0059] [1] A coil device comprising: a first magnetic material portion containing a magnetic material and having a plate-shaped portion and a protruding portion protruding from the plate-shaped portion; a winding portion in which a rectangular wire is wound so as to surround the periphery of the protruding portion; and a second magnetic material portion containing a magnetic material and a resin and covering at least the winding portion, wherein at least one non-magnetic gap containing no magnetic material is formed in an area covered by the second magnetic material portion in a predetermined cross section including a winding axis of the winding portion at which a wire cross section, which is a cross section of the rectangular wire wound so as to surround the periphery of the protruding portion, is observed.

[0060] [2] The winding section has a configuration in which the flat wire is wound in two or more stages in a winding axis direction parallel to the protruding direction of the protrusion, and in two or more rows in a radial direction perpendicular to the winding axis direction, and the wire gaps include wire gaps inside the winding section that circumscribe at least three different wire cross sections, and at least one of the wire gaps inside the winding section is the non-magnetic gap.

[0061] [3] The coil device according to the above [2], wherein there are a plurality of inter-wire gaps inside the winding portion, and all of the inter-wire gaps inside the winding portion are the non-magnetic material gaps.

[0062] [4] The coil device according to any one of [1] to [3] above, wherein the winding portion has a configuration in which the flat wire is wound in two or more rows in a radial direction perpendicular to the winding axis direction, the wire gaps have at least two different wire cross sections and plate-shaped portion wire gaps that circumscribe the plate-shaped portion, and at least one of the plate-shaped portion wire gaps is a non-magnetic gap that does not contain a magnetic material.

[0063] [5] The coil device according to the above [4], wherein there are a plurality of the plate-shaped portion inter-wire gaps, and all of the plate-shaped portion inter-wire gaps are the non-magnetic material gaps.

[0064] [6] The coil device according to any one of [1] to [5] above, wherein the winding section has a configuration in which the flat wire is wound in two or more stages in a winding axis direction parallel to the protruding direction of the protrusion, the wire gaps have at least two different wire cross sections and protrusion-wire gaps that circumscribe the protrusion, and at least one of the protrusion-wire gaps is a non-magnetic gap that does not contain a magnetic material.

[0065] [7] The coil device according to the above [6], wherein there are a plurality of the protrusion-wire gaps, and all of the protrusion-wire gaps are the non-magnetic material gaps.

[0066] [8] A coil device according to any one of [1] to [7] above, wherein the wire gap has a first magnetic material portion corner wire gap that circumscribes the wire cross section, the plate-shaped portion, and the protrusion, and the first magnetic material portion corner wire gap is the non-magnetic gap that does not contain a magnetic material.

[0067] [9] The coil device according to any one of [1] to [8] above, wherein the maximum length of the inter-wire gap in the cross section is smaller than the short side of the cross section of the rectangular wire.

[0068]

[10] The coil device according to any one of [1] to [9] above, wherein the winding portion has a configuration in which the rectangular wire is wound flatwise.

[0069]

[11] The coil device according to any one of [1] to [9] above, wherein the winding portion has a configuration in which the rectangular wire is wound edgewise.

[0070]

[12] The coil device according to any one of [1] to

[11] above, wherein the second magnetic material portion contains a smaller proportion of the magnetic substance than the first magnetic material portion.

[0071]

[13] The coil device according to any one of [1] to

[12] above, wherein the content of the magnetic body in the second magnetic material portion is 50% or more.

[0072] 10... Coil device 20... First magnetic material portion 22... Plate-shaped portion 22a... Plate-shaped portion side surface 22b... Plate-shaped portion bottom surface 22c... Plate-shaped portion top surface 24... Protruding portion 24a... Protruding portion side surface 30... Second magnetic material portion 31-32... Magnetic body 40... Wire 40a... Winding axis 41... Wire end portion 42... Winding portion 411-424... Wire cross section 81a-81c... Wire gaps inside winding portion (wire gaps) 82... Protruding portion wire gap 83... Corner wire gap (first magnetic material corner wire gap) 84a-84c... Plate-shaped portion wire gaps

Claims

1. A coil device comprising: a first magnetic material portion containing a magnetic material and having a plate-shaped portion and a protruding portion protruding from the plate-shaped portion; a winding portion in which a rectangular wire is wound so as to surround the periphery of the protruding portion; and a second magnetic material portion containing a magnetic material and a resin and covering at least the winding portion, wherein at least one non-magnetic gap containing no magnetic material is formed in the area covered by the second magnetic material portion in a predetermined cross section including the winding axis of the winding portion at which a wire cross section, which is a cross section of the rectangular wire wound so as to surround the periphery of the protruding portion, is observed.

2. The coil device described in claim 1, wherein the winding section has a configuration in which the flat wire is wound in two or more stages in the direction of the winding axis parallel to the protruding direction of the protrusion, and in two or more rows in the radial direction perpendicular to the direction of the winding axis, and the wire gaps include wire gaps inside the winding section that circumscribe at least three different wire cross sections, and at least one of the wire gaps inside the winding section is the non-magnetic gap.

3. A coil device according to claim 2, wherein there are a plurality of inter-wire gaps within the winding portion, and all of the inter-wire gaps within the winding portion are the non-magnetic gaps.

4. The coil device described in claim 1, wherein the winding portion has a configuration in which the flat wire is wound in two or more rows in a radial direction perpendicular to the winding axis direction, the wire gaps have at least two different wire cross sections and plate-like portion wire gaps that circumscribe the plate-like portion, and at least one of the plate-like portion wire gaps is a non-magnetic gap that does not contain a magnetic material.

5. A coil device according to claim 4, wherein there are a plurality of gaps between the plate-shaped portion and the wires, all of which are non-magnetic gaps.

6. The coil device according to claim 1, wherein the winding section has a configuration in which the flat wire is wound in two or more stages in a winding axis direction parallel to the protruding direction of the protrusion, the wire gaps have at least two different wire cross sections and protrusion-wire gaps circumscribing the protrusion, and at least one of the protrusion-wire gaps is a non-magnetic gap that does not contain a magnetic material.

7. A coil device according to claim 6, wherein there are a plurality of gaps between the protrusions and the wires, and all of the gaps between the protrusions and the wires are the non-magnetic gaps.

8. A coil device as described in claim 1, wherein the wire gap has a first magnetic material portion corner wire gap that circumscribes the wire cross section, the plate-shaped portion, and the protrusion, and the first magnetic material portion corner wire gap is a non-magnetic gap that does not contain a magnetic material.

9. A coil device according to any one of claims 1 to 8, wherein the maximum length of the inter-wire gap in the cross section is smaller than the short side of the cross section of the rectangular wire.

10. A coil device according to any one of claims 1 to 8, wherein the winding portion has a configuration in which the rectangular wire is wound flatwise.

11. A coil device according to any one of claims 1 to 8, wherein the winding portion has a configuration in which the rectangular wire is wound edgewise.

12. A coil device according to any one of claims 1 to 8, wherein the second magnetic material portion contains a smaller proportion of the magnetic substance than the first magnetic material portion.

13. A coil device according to any one of claims 1 to 8, wherein the content of magnetic material in the second magnetic material portion is 50% or more.

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