Coil component and filter circuit

Abstract

A coil component (1) according to the present disclosure comprises a housing (4), a coil (L1), and a coil (L2). In the housing (4), discontinuous regions (41a)-(41d) and discontinuous regions (42a)-(42d) extending from the surface of the coil (L1) and / or the coil (L2) to a main surface of the housing (4) are formed.

Description

Coil components and filter circuits

[0001] The present disclosure relates to a coil component and a filter circuit that implements the coil component.

[0002] Conventionally, there have been coil components in which a coil is formed by bending a metal plate. Japanese Patent Laid-Open Publication No. 2004-296630 (Patent Document 1) discloses, as an example of a coil component, a coil component having four terminals extending outward from a main body portion.

[0003] Japanese Patent Application Laid-Open No. 2004-296630

[0004] When a coil component is used in a power line, exposure to a surge greater than the rated current can cause the coil to heat up suddenly, potentially causing the housing portion made of resin or the like near the coil to expand due to the heat. Japanese Patent Laid-Open No. 2004-296630 (Patent Document 1) uses a material with high heat dissipation properties for the surface of the housing, but does not fully consider the sudden heat generation from the coil.

[0005] An object of the present disclosure is to provide a coil component that can absorb volume expansion of a housing even when the coil portion suddenly generates heat, and a filter circuit in which the coil component is mounted.

[0006] A coil component according to one embodiment of the present disclosure includes: a housing having a pair of first and second principal surfaces opposing each other and four side surfaces connecting the first and second principal surfaces; a first coil conductor disposed inside the housing and having a first coil section with an opening and first and second lead wires drawn from the first coil section; a second coil section disposed inside the housing and having an opening that at least partially overlaps with the opening of the first coil section when viewed from the direction in which the first and second principal surfaces face each other; and a second coil conductor having third and fourth lead wires drawn from the second coil section. A discontinuous region is formed in the housing.

[0007] A filter circuit according to an embodiment of the present disclosure includes the above-described coil component and a capacitor connected to the coil component.

[0008] According to one aspect of the present disclosure, the housing has a discontinuous region formed therein, which allows the volume expansion of the housing to be absorbed by the discontinuous region even when the coil portion is suddenly heated.

[0009] 1 is a perspective view of a coil component according to a first embodiment. 2 is a front view of the coil component according to the first embodiment. 3 is a right side view of the coil component according to the first embodiment. 4 is a plan view of the coil component according to the first embodiment. 5 is a bottom view of the coil component according to the first embodiment. 6 is a cross-sectional view taken along line VI-VI in the plan view of the coil component according to the first embodiment. 7 is a circuit diagram of a filter circuit including the coil component according to the first embodiment. 8 is a perspective view of a coil component according to a second embodiment. 9 is a bottom view of a coil component according to a third embodiment. 10 is a cross-sectional view of the coil component according to the third embodiment. 11 is a bottom view of a coil component according to a fourth embodiment. 12 is a cross-sectional view of the coil component according to the fourth embodiment. 13 is a cross-sectional view of the coil component according to the fourth embodiment. 14 is a cross-sectional view of the coil component according to the fifth embodiment.

[0010] <First Embodiment> A coil component according to the first embodiment will be described below. FIG. 1 is a perspective view of the coil component 1 according to the first embodiment. FIG. 2 is a front view of the coil component 1 according to the first embodiment. FIG. 3 is a right side view of the coil component 1 according to the first embodiment. FIG. 4 is a plan view of the coil component 1 according to the first embodiment. FIG. 5 is a bottom view of the coil component 1 according to the first embodiment. FIG. 6 is a cross-sectional view taken along line VI-VI in the plan view of the coil component 1 according to the first embodiment. When the X-axis, Y-axis, and Z-axis are defined as shown in FIGS. 1 to 6, the X-axis direction is the left-right direction of the coil component 1, the Y-axis direction is the front-rear direction of the coil component 1, and the Z-axis direction is the up-down direction of the coil component 1.

[0011] The coil component 1 is, for example, a transformer coil mounted in a filter circuit 100 used to reduce noise in a power line. As will be described later, the coil component 1 magnetically couples two coils to cancel the parasitic inductance of a capacitor mounted in the filter circuit.

[0012] The coil component 1 includes a housing 4, a coil portion 2a (first coil portion) having a rectangular opening, and a coil portion 3a (second coil portion) having a rectangular opening. Hereinafter, the coil portion 2a will also be referred to as coil L1, and the coil portion 3a will also be referred to as coil L2. The coils L1 and L2 are conductors formed from metal plates, such as copper or an alloy of copper and other metals. The main component of the coils L1 and L2 is copper, with the copper content being at least 50% or more, preferably 80% or more.

[0013] The coils L1 and L2, which are formed from metal plates, are covered with an insulating material (not shown). Specifically, the insulating material covering the coils L1 and L2 is a resin such as polyimide or epoxy. Note that the insulating material does not need to cover all surfaces of the coils L1 and L2. To prevent contact between the coils L1 and L2, it is sufficient that the insulating material is provided at least on the surfaces where the coils L1 and L2 face each other. Furthermore, although a single-turn coil is illustrated in the present disclosure, a multiple-turn coil may also be used.

[0014] The housing 4 has a pair of opposing first and second main surfaces, a flat surface 41 and a bottom surface 42, respectively, and four side surfaces connecting the flat surface 41 and the bottom surface 42, namely a right side surface 43, a left side surface 44, a front surface 45, and a back surface 46. Each surface is one side of the housing 4 when viewed as a substantially rectangular parallelepiped, and does not necessarily have to be flat, and each surface may have projections and recesses. The flat surface 41 and the bottom surface 42 may have different areas, and each side surface may be trapezoidal.

[0015] The housing 4 is made of molded resin for fixing the coils L1 and L2. Specifically, the molded resin is made of one of epoxy resin with added silica filler, silicone resin, liquid crystal polymer, or various resins mixed with metal magnetic material. The resin inside the housing 4 may be made of multiple resins.

[0016] The coil portion 2a has a lead wire 2b (first lead wire) connected to one end and a lead wire 2d (second lead wire) connected to the other end. Furthermore, the lead wire 2b is provided with an electrode 2c that functions as an electrode, and the lead wire 2d is provided with an electrode 2e that functions as an electrode. The coil portion 2a and the lead wires 2b and 2d form a single first conductor 2 (first coil conductor). The lead wires 2b and 2d are also terminals extending from one end of the coil portion 2a, and are therefore also referred to as terminals 2b and 2d.

[0017] The coil portion 3a has one end connected to a lead wire 3b (third lead wire) and the other end connected to a lead wire 3d (fourth lead wire). Furthermore, the lead wire 3b is provided with an electrode 3c that functions as an electrode, and the lead wire 3d is provided with an electrode 3e that functions as an electrode. The coil portion 3a and the lead wires 3b and 3d form a single second conductor 3 (second coil conductor). The lead wires 3b and 3d are also terminals extending from one end of the coil portion 3a, and are therefore also referred to as terminals 3b and 3d.

[0018] The first conductor 2 including the coil L1 and the second conductor 3 including the coil L2 are formed by punching out a pattern from a single metal plate and bending the punched pattern. The bent portions between the coil L1 (coil portion 2a) and the lead wires 2b and 2d, and the bent portions between the electrodes 2c and 2e and the other regions of the lead wires 2b and 2d, are formed by bending, resulting in a substantially right-angle structure with a radius of curvature. Similarly, the bent portions between the coil L2 (coil portion 3a) and the lead wires 3b and 3d, and the bent portions between the electrodes 3c and 3e and the other regions of the lead wires 3b and 3d, are also formed by bending, resulting in a substantially right-angle structure with a radius of curvature. In this way, the bent portions form arcs with a constant radius. The first conductor 2 and the second conductor 3 may also be formed from one or more wires, and the wires may be similarly bent to form arcs with a constant radius at the bent portions.

[0019] The coils L1 and L2 are arranged so that their openings overlap. While FIG. 1 shows an example in which the openings nearly overlap, the openings may be offset as long as magnetic field coupling is achieved, and the overlapping of 50% or more of the openings is sufficient. A magnetic field is generated in the coil L1 when a current flows from the electrode 2c of the first conductor 2, and a magnetic field in the same direction as the magnetic field of the coil L1 is generated in the coil L2 when a current flows from the electrode 2e to the coil L2 through the electrode 3e of the second conductor 3. The coils L1 and L2 are connected at the electrode 2e and the electrode 3e on the mounting board.

[0020] At the positions where the coil portion 2a connects to the lead wires 2b and 2d, the closer the distance between the lead wires 2b and 2d, the closer the coil opening, thereby increasing the magnetic flux density and therefore the higher the inductance. On the other hand, the electrodes 2c and 2e are spaced farther apart to avoid short circuits when mounted on a mounting board. Similarly, at the positions where the coil portion 3a connects to the lead wires 3b and 3d, the closer the distance between the lead wires 3b and 3d, the closer the coil opening, thereby increasing the magnetic flux density and therefore the higher the inductance. On the other hand, the electrodes 3c and 3e are spaced farther apart to avoid short circuits when mounted on a mounting board. Thus, the lead wires 2b and 2d are shaped to splay outward from their lead wire positions on the left side surface 44 before extending to the bottom surface 42, which is the second main surface. Similarly, the lead wires 3b and 3d are shaped to splay outward from their lead wire positions on the right side surface 43 before extending to the bottom surface 42, which is the second main surface.

[0021] The coil component 1 has a protrusion 4c on the bottom surface 42 of the housing 4. The protrusions 4c are cross-shaped protrusions disposed between the lead wires 2b, 2d, 3b, and 3d, extending in the X-axis and Y-axis directions. The protrusions 4c are formed by cutting out four corners of the housing 4. The protrusions 4c prevent deformation of the lead wires 2b, 2d, 3b, and 3d, including the electrodes 2c, 2e, 3c, and 3e. The coil component 1 has a small gap between the protrusion 4c and the electrodes 2c, 2e, 3c, and 3e, which are part of the lead wires 2b, 2d, 3b, and 3d, to allow for thermal expansion and contraction. The protrusions may also be provided on the side surfaces of the housing. The electrodes 2c, 2e, 3c, and 3e are used as mounting electrodes when mounted on a substrate.

[0022] In the coil component 1, the coil L2 (coil portion 3a) is arranged on the flat surface 41 side, which is the first main surface of the housing 4, and the coil L1 (coil portion 2a) is arranged on the bottom surface 42 side, which is the second main surface of the housing 4. The coil component 1 is formed with discontinuous regions 41a, 41b, 41c, and 41d, which are openings extending from the first main surface of the coil L2 (coil portion 3a) to the flat surface 41. The coil component 1 is formed with discontinuous regions 42a, 42b, 42c, and 42d, which are openings extending from the second main surface of the coil L1 (coil portion 2a) to the bottom surface 42. Note that, although the shapes of the discontinuous regions 41a to 41d (first discontinuous regions) and the discontinuous regions 42a to 42d (second discontinuous regions) in the present disclosure are cylindrical, they may have any shape, not limited to a cylindrical shape.

[0023] The discontinuous regions 42a to 42d extend perpendicularly from the surface of the coil L1 to the bottom surface 42 of the housing 4. Similarly, the discontinuous regions 41a to 41d extend perpendicularly from the surface of the coil L2 to the flat surface 41 of the housing 4. If the opening is cylindrical, the central axis of the cylinder should be perpendicular to the surface of the coil L1 or coil L2, and if it is conical, the central axis of the cone should be perpendicular to the coil L1 or coil L2. It is particularly preferable that the opening be cylindrical. By making the discontinuous regions cylindrical, the pressure from the resin can be uniformly distributed and deformation can be suppressed.

[0024] The housing 4 is made of molded resin. As shown in Fig. 6, the coil component 1 has the space between the coil L1 (coil portion 2a) and the coil L2 (coil portion 3a) filled with molded resin. This prevents contact between the coil L1 (coil portion 2a) and the coil L2 (coil portion 3a).

[0025] 6, the length r1 in the Z-axis direction of each of the discontinuous regions 41a, 41b, 41c, and 41d (the length from the surface of the coil portion 3a to the plane 41) is longer than the length r3 in the Z-axis direction between the coil L1 (coil portion 2a) and the coil L2 (coil portion 3a). As shown in FIG. 6, the length r2 in the Z-axis direction of each of the discontinuous regions 42a, 42b, 42c, and 42d (the length from the surface of the coil portion 2a to the bottom surface 42) is longer than the length r3 in the Z-axis direction between the coil L1 (coil portion 2a) and the coil L2 (coil portion 3a).

[0026] The temperature tends to be highest between the two heat-generating coils. However, in the coil component 1, discontinuous regions 41a-41d and 42a-42d longer than the inter-coil distance r3 are formed at the positions that will be the hottest even if coil L1 (coil portion 2a) and coil L2 (coil portion 3a) suddenly heat up, so that the volume expansion of the housing 4 can be absorbed. This makes it possible for the coil component 1 to prevent rupture due to thermal expansion of the housing 4.

[0027] In the coil component 1, the length r1 of the upper discontinuous regions 41a to 41d in the Z-axis direction is shorter than the length r2 of the lower discontinuous regions 42a to 42d, which allows the overall height of the housing 4 to be reduced and allows each of the discontinuous regions 41a to 41d and 42a to 42d to have an appropriate length to match the shape of the coil component 1, which requires sufficient lead wire length.

[0028] The coil L1 (coil portion 2a) and the coil L2 (coil portion 3a) are generally rectangular when viewed from the direction in which the first and second principal surfaces of the housing face each other (the Z-axis direction in the figure). The discontinuous regions 41a, 41b, 41c, and 41d are provided at each corner of the generally rectangular coil L2 (coil portion 3a). The discontinuous regions 42a, 42b, 42c, and 42d are provided at each corner of the generally rectangular coil L1 (coil portion 2a). Here, "approximately rectangular" refers to a shape with four sides, and includes coils with significantly rounded corners. Although the coils shown in this embodiment are generally rectangular, the coils may be elliptical, circular, or other polygonal shapes.

[0029] Although the case where a total of eight discontinuous regions are provided has been described, it is sufficient that there is at least one location that extends from the surface of at least one of coil L1 (coil portion 2a) or coil L2 (coil portion 3a) to the surface of housing 4. By providing multiple discontinuous regions, if coil L1 (coil portion 2a) and coil L2 (coil portion 3a) suddenly generate heat, the volume expansion of housing 4 can be absorbed at multiple positions on the coils.

[0030] The discontinuous regions may be located anywhere in the substantially rectangular coil L1 or L2, but are preferably provided at the corners of the substantially rectangular coil L1 and coil L2, because the corners of the substantially rectangular coils L1 and L2 are the portions where the coil width is greatest in the XY plane, allowing for more efficient heat dissipation.

[0031] The discontinuous regions 42a to 42d, which are second discontinuous regions provided on the surface of the coil L1, and the discontinuous regions 41a to 41d, which are first discontinuous regions provided on the surface of the coil L2, may be located at the same position or at different positions.

[0032] By providing discontinuous regions, air enters the resin. Compared to molded resin, air has a lower heat dissipation property, so heat tends to accumulate in the areas where discontinuous regions exist. By arranging discontinuous regions 41a-41d and discontinuous regions 42a-42d in the same positions, it is possible to prevent an increase in the number of discontinuous regions while increasing the number of discontinuous regions, compared to a structure in which discontinuous regions 41a-41d and discontinuous regions 42a-42d are arranged in different positions.

[0033] When the discontinuous regions 41a-41d and the discontinuous regions 42a-42d are located at different positions, it is preferable to make the distance between each discontinuous region equal. Specifically, it is possible to form the discontinuous regions 41a-41d at each corner of the coil L2, and the discontinuous regions 42a-42d at the midpoints of each side of the coil L1. In other words, it is preferable to form the discontinuous regions so that the distance between each discontinuous region and the distance between the first discontinuous region and the second discontinuous region are equal. This configuration suppresses uneven heat dissipation due to coil position and enables heat dissipation throughout the entire coil.

[0034] The discontinuous region may have a shape in which the maximum diameter (opening width of the coil) increases from r4 to r5 as it approaches the flat surface 41 from the coil surface, as in discontinuous regions 41a to 41d shown in Figure 6, or may have a cylindrical shape with a constant maximum diameter (opening width of the coil) r6 as in discontinuous regions 42a to 42d. Alternatively, the discontinuous region may have a shape in which the maximum diameter decreases as it approaches the flat surface 41 or the bottom surface 42 from the coil surface. Furthermore, the shapes of the upper and lower discontinuous regions may be different or the same, as shown in Figure 6.

[0035] 6, the opening width r4 at the contact points between the discontinuous regions 41a to 41d and the coil L2 is narrower than the width of the coil L2. The opening width r6 at the contact points between the discontinuous regions 42a to 42d and the coil L1 is narrower than the width of the coil L1. This makes it possible to absorb the expansion of the resin while keeping the area of ​​the discontinuous regions smaller than the coil width.

[0036] The positional relationship between the discontinuous region and the coil and the maximum diameter of the discontinuous region are not particularly limited. By arranging the discontinuous region so that it is smaller than the coil width and overlaps the coil in a top view, it is possible to absorb the expansion of the resin while suppressing the area of ​​the discontinuous region.

[0037] When the coil component 1 used in the power line is exposed to a surge exceeding the rated current, the coils L1 and L2 may suddenly heat up, causing the resin near the coils L1 (coil portion 2a) and L2 (coil portion 3a) to expand in volume. If no discontinuous region is formed in the housing 4, the expanded resin will have nowhere to go, which could lead to the coil component 1 bursting.

[0038] The coil component 1 of the present disclosure has discontinuous regions 41a, 41b, 41c, and 41d formed from the surface of the coil L2 (coil portion 3a) to the plane 41, and discontinuous regions 42a, 42b, 42c, and 42d formed from the surface of the coil L1 (coil portion 2a) to the bottom surface 42. Even if the coil L1 (coil portion 2a) and the coil L2 (coil portion 3a) suddenly generate heat, the coil component 1 can absorb the volumetric expansion of the housing 4 by the discontinuous regions 41a to 41d and 42a to 42d. This allows the coil component 1 to prevent rupture due to thermal expansion of the housing 4.

[0039] In the coil component 1, the metal forming the coil itself may expand due to high temperatures in the coil L1 (coil portion 2a) and the coil L2 (coil portion 3a). In the coil component 1, the expansion of the metal itself can be absorbed by the discontinuous regions 41a to 41d and 42a to 42d.

[0040] 7 is a circuit diagram of a filter circuit 100 including the coil device 1 according to the first embodiment. The filter circuit 100 is, for example, an EMI removal filter, and is a third-order T-type LC filter circuit. In this filter circuit 100, the electrode 2c is connected to a power supply (not shown), and the electrode 3c is connected to a circuit (not shown) such as a DC / DC converter or a power supply module. The filter circuit 100 passes necessary components of the current flowing from the power supply to the circuit and removes unnecessary components.

[0041] Specifically, a direct current is passed through the filter circuit 100, and high-frequency noise contained in the direct current is dropped to GND via capacitor C1. Capacitor C1, which is a capacitance element, has an equivalent series inductance (ESL) (La), which prevents high-frequency noise from passing through it, degrading noise removal performance. This filter circuit 100 uses negative inductance generated in series with capacitor C1 due to the mutual inductance caused by the magnetic coupling of the two coils to cancel the capacitor's ESL (La), thereby maintaining high noise removal performance.

[0042] In the following embodiment, a third-order T-type LC filter circuit will be used as the configuration of the filter circuit 100, but coil components with similar configurations can also be applied to fifth-order T-type LC filter circuits or higher-order T-type LC filter circuits. As shown in Fig. 7, the filter circuit 100 includes a coil component 1 and a capacitor C1. The coil component 1 includes electrodes 2c and 3c, an intermediate terminal T (electrodes 2e and 3e), a coil L1, and a coil L2.

[0043] As shown in FIG. 7, one end of the capacitor C1 is connected to the intermediate terminal T, and the other end is connected to the GND wiring. The capacitor C1 is made of BaTiO ３ The present invention is not limited to multilayer ceramic capacitors primarily composed of barium titanate (barium titanate), but may also include multilayer ceramic capacitors primarily composed of other materials, or other types of capacitors other than multilayer ceramic capacitors, such as aluminum electrolytic capacitors. Capacitor C1 has an inductor La as a parasitic inductance (equivalent series inductance (ESL)), and is equivalent to a circuit configuration in which inductor La is connected in series with capacitor C1a. Capacitor C1 may also be equivalent to a circuit configuration in which parasitic resistance (equivalent series resistance (ESR)) is connected in series with inductor La and capacitor C1a.

[0044] In addition to the capacitor C1, the coils L1 and L2 are also connected to the intermediate terminal T. That is, the intermediate terminal T is located on the wiring connecting the electrode 2e of the coil L1 and the electrode 3c of the coil L2 on the mounting board. The coils L1 and L2 are magnetically coupled and have mutual inductance. A negative inductance component of the same magnitude as the mutual inductance is generated between the intermediate terminal T and the capacitor C1. This negative inductance component can be used to cancel out the parasitic inductance (inductor La) of the capacitor C1, thereby making the parasitic inductance component of the capacitor C1 appear smaller. In other words, the filter circuit 100, which is composed of the capacitor C1, the coil L1, and the coil L2, cancels out the parasitic inductance of the capacitor C1 with the negative inductance component due to the mutual inductance between the coils L1 and L2, thereby suppressing the reduction in the noise suppression effect in the high frequency band caused by the parasitic inductance of the capacitor C1 and improving the noise suppression effect of the filter circuit 100.

[0045] <Embodiment 2> In embodiment 2, a configuration will be described in which, as compared with embodiment 1, a discontinuous region is present on the side surface of housing 4. Fig. 8 is a perspective view of coil component 1A according to embodiment 2. Note that in coil component 1A shown in embodiment 2, the same components as those in coil component 1 according to embodiment 1 are designated by the same reference numerals and detailed description thereof will not be repeated.

[0046] Coil device 1A has discontinuous regions 45a, 45b, 45c, and 45d formed on front surface 45, which is a side surface of housing 4. Discontinuous regions 45c and 45d, which are third discontinuous regions, are formed in a portion extending from the surface of coil L1 (coil portion 2a) to front surface 45. Discontinuous regions 45a and 45b, which are fourth discontinuous regions, are formed in a portion extending from the surface of coil L2 (coil portion 3a) to front surface 45.

[0047] The discontinuous regions 45a to 45d are rectangular parallelepiped-shaped, but may be cylindrical as in the coil component 1 of embodiment 1, or may have any other shape. In the coil component 1A, the discontinuous regions are formed only on the front surface 45 of the housing 4, but discontinuous regions may also be formed on other surfaces. The discontinuous regions may have one or more locations that extend from the surface of at least one of the coil L1 (coil portion 2a) or the coil L2 (coil portion 3a) to the surface of the housing 4.

[0048] Coil component 1A of the present disclosure has discontinuous regions 45a and 45b formed from the surface of coil L2 (coil portion 3a) to front surface 45, and discontinuous regions 45c and 45d formed from the surface of coil L1 (coil portion 2a) to front surface 45. Coil component 1A can absorb the volumetric expansion of housing 4 by each of discontinuous regions 45a to 45d even when coil L1 (coil portion 2a) and coil L2 (coil portion 3a) suddenly generate heat. This allows coil component 1A to prevent rupture due to thermal expansion of housing 4.

[0049] <Modifications> In the above-described embodiment, the discontinuous region has been described as extending from the surface of coil L1 (coil portion 2a) or coil L2 (coil portion 3a) to the surface of the housing 4. A cavity may be formed that does not extend from the surface of coil L1 (coil portion 2a) or coil L2 (coil portion 3a) to the surface of the housing 4 but stops midway. Similarly, a cavity may be formed that does not extend from the surface of the housing 4 to the surface of coil L1 (coil portion 2a) or coil L2 (coil portion 3a) but stops midway. The cavity may be formed in the direction from the surface of coil L1 (coil portion 2a) or coil L2 (coil portion 3a) toward the surface of the housing 4, and may be formed anywhere on the coil surface as long as it is a space other than between the coils.

[0050] <Embodiment 3> Next, a coil component 1B according to embodiment 3 will be described. In embodiment 3, a configuration will be described in which, compared to embodiment 1, a discontinuous region penetrates from the first main surface (flat surface 41) to the second main surface (bottom surface 42). FIG. 9 is a bottom view of coil component 1B according to embodiment 3. FIG. 10 is a cross-sectional view of coil component 1B according to embodiment 3. Note that in coil component 1B shown in embodiment 3, the same components as those in coil component 1 according to embodiment 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated. Also, the position of the cross-sectional view in FIG. 10 is the same as the position of the cross-sectional view in FIG. 6.

[0051] The discontinuous regions 5a, 5b of the coil component 1B are formed penetrating from the first main surface (flat surface 41) to the second main surface (bottom surface 42). In this way, the discontinuous regions 5a, 5b are through holes penetrating the housing 4. The number of discontinuous regions may be any number greater than or equal to two. Note that the coil component 1B has openings (discontinuous regions 41b, 41c, etc.) extending from the first main surface of the coil L2 (coil portion 3a) to the flat surface 41, but openings do not necessarily have to be provided. Furthermore, the coil component 1B does not have openings extending from the second main surface of the coil L1 (coil portion 2a) to the bottom surface 42, but openings may be provided.

[0052] Coil component 1B of the present disclosure has discontinuous regions 5a, 5b formed penetrating from the first main surface (flat surface 41) to the second main surface (bottom surface 42). Coil component 1B can absorb the volumetric expansion of housing 4 by each of discontinuous regions 5a, 5b even when coil L1 (coil portion 2a) and coil L2 (coil portion 3a) suddenly generate heat. This makes it possible for coil component 1B to prevent rupture due to thermal expansion of housing 4.

[0053] <Fourth Embodiment> Next, a coil component 1C according to a fourth embodiment will be described. In the fourth embodiment, a configuration will be described in which, compared to the third embodiment, the discontinuous region extends from the second main surface (bottom surface 42) to partway along the first main surface (flat surface 41). FIG. 11 is a bottom view of the coil component 1C according to the fourth embodiment. FIG. 12 is a cross-sectional view of the coil component 1C according to the fourth embodiment. Note that in the coil component 1C shown in the fourth embodiment, the same components as those in the coil component 1 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will not be repeated. Furthermore, the position of the cross-sectional view in FIG. 12 is the same as the position of the cross-sectional view in FIG. 6.

[0054] The discontinuous regions 5c and 5d of the coil component 1C extend from the second main surface (bottom surface 42) to a position partway to the first main surface (flat surface 41). Thus, the discontinuous regions 5c and 5d are holes formed from the second main surface (bottom surface 42) to a position partway through the housing 4. The number of discontinuous regions may be any number greater than or equal to two. Note that the coil component 1C has openings (discontinuous regions 41b, 41c, etc.) formed from the first main surface of the coil L2 (coil portion 3a) to the flat surface 41, but openings do not necessarily have to be provided. Furthermore, the coil component 1C does not have openings formed from the second main surface of the coil L1 (coil portion 2a) to the bottom surface 42, but openings may be formed. The discontinuous regions may extend from the first main surface (flat surface 41) to a position partway to the second main surface (bottom surface 42).

[0055] The coil component 1C of the present disclosure has discontinuous regions 5c and 5d formed extending from the second main surface (bottom surface 42) to partway along the first main surface (flat surface 41). Even when the coil L1 (coil portion 2a) and the coil L2 (coil portion 3a) suddenly generate heat, the coil component 1C can absorb the volumetric expansion of the housing 4 through the discontinuous regions 5c and 5d. This prevents the coil component 1C from bursting due to thermal expansion of the housing 4.

[0056] <Fifth Embodiment> Next, a coil component 1D according to a fifth embodiment will be described. In the fifth embodiment, compared to the first embodiment, the coil L1 (coil portion 2a) and the coil L2 (coil portion 3a) are inclined with respect to the first main surface (plane 41), and a discontinuous region extends to the inclined surfaces of the coil L1 (coil portion 2a) and the coil L2 (coil portion 3a). FIG. 13 is a cross-sectional view of the coil component 1D according to the fifth embodiment. Note that in the coil component 1D shown in the fifth embodiment, the same components as those in the coil component 1 according to the first embodiment are designated by the same reference numerals, and detailed description thereof will not be repeated. Furthermore, the position of the cross-sectional view in FIG. 13 is the same as the position of the cross-sectional view in FIG. 6.

[0057] In coil device 1D, coil L1 (coil portion 2a) and coil L2 (coil portion 3a) are arranged parallel to each other and inclined with respect to the first main surface (plane 41) when viewed from the side of housing 4. As shown in Fig. 13 , coil L1 (coil portion 2a) and coil L2 (coil portion 3a) are inclined downwards toward the positive direction of the X axis (inclined toward the negative direction of the Z axis). Coil L1 (coil portion 2a) and coil L2 (coil portion 3a) may also be inclined upwards toward the positive direction of the X axis (inclined toward the positive direction of the Z axis).

[0058] The discontinuous regions 5e and 5f are formed to extend perpendicularly from the first main surface (flat surface 41) to the surface of the coil L1 (coil portion 2a). The discontinuous regions 5g and 5h are formed to extend perpendicularly from the second main surface (bottom surface 42) to the surface of the coil L2 (coil portion 3a). The contact surfaces of the discontinuous regions 5g and 5h with the surface of the coil L2 (coil portion 3a) and the contact surfaces of the discontinuous regions 5e and 5f with the surface of the coil L1 (coil portion 2a) have curvature. The discontinuous regions of the coil component 1D may extend perpendicularly from at least one of the first main surface (flat surface 41) or the second main surface (bottom surface 42) to the surface of the coil L1 (coil portion 2a) or the surface of the coil L2 (coil portion 3a).

[0059] In the coil component 1D of the present disclosure, the coil L1 (coil portion 2a) and the coil L2 (coil portion 3a) are arranged parallel to each other and are inclined with respect to the first main surface (plane 41) when viewed from the side of the housing 4. The discontinuous regions 5e and 5f are formed to extend perpendicularly from the first main surface (plane 41) to the surface of the coil L1 (coil portion 2a), and the discontinuous regions 5g and 5h are formed to extend perpendicularly from the second main surface (bottom surface 42) to the surface of the coil L2 (coil portion 3a). This makes it possible for the coil component 1D to prevent rupture due to thermal expansion of the housing 4 even when the coil L1 (coil portion 2a) and the coil L2 (coil portion 3a) are inclined with respect to the first main surface (plane 41) when viewed from the side of the housing 4.

[0060] <Aspects> (1) A coil component according to the present disclosure includes: a housing having a pair of first and second principal surfaces opposing each other and four side surfaces connecting the first and second principal surfaces; a first coil conductor disposed inside the housing and having a first coil section with an opening; a first coil conductor having first and second lead wires drawn from the first coil section; a second coil section disposed inside the housing and having an opening that at least partially overlaps with the opening of the first coil section when viewed from the direction in which the first and second principal surfaces face each other; and a second coil conductor having third and fourth lead wires drawn from the second coil section. A discontinuous region is formed in the housing.

[0061] According to the coil component of the present disclosure, even if the coil portion suddenly generates heat, the discontinuous region can absorb the volume expansion of the housing.

[0062] (2) In the coil component according to (1), the discontinuous region extends from the surface of at least one of the first coil portion and the second coil portion to the main surface or the side surface of the housing.

[0063] According to the coil component of the present disclosure, the volume expansion of the housing can be absorbed by the discontinuous region extending from the surface of at least one of the first coil portion and the second coil portion to the main surface or side surface of the housing.

[0064] (3) In the coil component according to (1) or (2), the discontinuous region extends perpendicular to the surface of the first coil portion or the second coil portion.

[0065] According to the coil component of the present disclosure, the volume expansion of the housing can be absorbed by the discontinuous region extending perpendicular to the surface of the first coil portion or the second coil portion.

[0066] (4) A coil component according to any one of (1) to (3), wherein the length from the surface of the first coil portion or the second coil portion in the discontinuous region to the main surface or side surface of the housing is longer than the length between the first coil portion and the second coil portion.

[0067] According to the coil component of the present disclosure, the discontinuous region is formed at the position that is most likely to become hot, and therefore, the volume expansion of the housing can be absorbed.

[0068] (5) The coil component according to any one of (1) to (4), wherein a discontinuous region is formed in each of the first coil portion and the second coil portion.

[0069] According to the coil component of the present disclosure, it is possible to absorb the volume expansion of the housing caused by heat generated by either the first coil portion or the second coil portion.

[0070] (6) The coil component according to any one of (1) to (5), wherein the coil component has a second coil portion disposed on the first principal surface side and a first coil portion disposed on the second principal surface side, and includes a first discontinuous region extending from the first principal surface side surface of the second coil portion to the first principal surface, and a second discontinuous region extending from the second principal surface side surface of the first coil portion to the second principal surface.

[0071] According to the coil component of the present disclosure, even if the coil portion suddenly generates heat, the discontinuous region can absorb the volume expansion of the housing.

[0072] (7) The coil component according to (6), wherein the first lead wire, the second lead wire, the third lead wire, and the fourth lead wire are extended to a second main surface side of the housing, and the second main surface side includes an electrode for mounting. The length of the first discontinuous region is shorter than the length of the second discontinuous region.

[0073] According to the coil component of the present disclosure, the length of the discontinuous region can be set according to the shape of the housing.

[0074] (8) The coil component according to any one of (1) to (7), wherein the first coil portion and the second coil portion are substantially rectangular, and the discontinuous region is provided at at least one corner of the first coil portion or the second coil portion.

[0075] According to the coil component of the present disclosure, even if the coil portion suddenly generates heat, the volume expansion of the housing can be absorbed by the discontinuous region formed at the corner where the coil width is large.

[0076] (9) A coil component according to any one of (1) to (8), wherein the opening width of the contact point between the discontinuous region and the first coil portion or the second coil portion is narrower than the width of the first coil portion or the second coil portion.

[0077] According to the coil component of the present disclosure, it is possible to absorb the expansion of the resin while keeping the area of ​​the discontinuous region smaller than the coil width.

[0078] (10) The coil component according to any one of (1) to (9), wherein the first and second lead wires are drawn from a first position on a first side surface of the housing where the distance between them narrows, and the third and fourth lead wires are drawn from a second position on a second side surface of the housing where the distance between them narrows. The coil component further comprises a third discontinuous region extending from a surface of the first coil portion to at least one of the third side surface of the housing or the fourth side surface of the housing, and a fourth discontinuous region extending from a surface of the second coil portion to at least one of the third side surface of the housing or the fourth side surface.

[0079] According to the coil component of the present disclosure, even if the coil portion suddenly generates heat, the discontinuous region can absorb the volume expansion of the housing.

[0080] (11) In the coil component according to (1), the discontinuous region penetrates from the first main surface to the second main surface.

[0081] According to the coil component of the present disclosure, even if the coil portion suddenly generates heat, the discontinuous region can absorb the volume expansion of the housing.

[0082] (12) In the coil component according to (1), the discontinuous region extends from one of the first main surface and the second main surface to a position midway along the main surface to the other main surface.

[0083] According to the coil component of the present disclosure, even if the coil portion suddenly generates heat, the discontinuous region can absorb the volume expansion of the housing.

[0084] (13) The coil component according to (1), wherein the first coil portion and the second coil portion are arranged parallel to each other and inclined relative to the first main surface when viewed from a side of the housing, and the discontinuous region extends perpendicularly from at least one of the first main surface and the second main surface to the surface of the first coil portion or the surface of the second coil portion.

[0085] According to the coil component of the present disclosure, even if the coil portion suddenly generates heat, the discontinuous region can absorb the volume expansion of the housing.

[0086] (14) A filter circuit according to the present disclosure includes the coil component according to any one of (1) to (13) and a capacitor connected to the coil component.

[0087] According to the filter circuit of the present disclosure, it is possible to provide a filter circuit including a coil component that can absorb volume expansion of the housing by the discontinuous region even when the coil portion suddenly generates heat.

[0088] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0089] 1, 1A Coil component, 2 First conductor, 2a, 3a Coil portion, 2b, 2d, 3b, 3d Lead wire, 2c, 2e, 3c, 3e Electrode, 3 Second conductor, 4 Housing, 4c Convex portion, 41a, 41b, 41c, 41d, 42a, 42b, 42c, 42d, 45a, 45b, 45c, 45d Discontinuous region, 41 Plane, 42 Bottom surface, 43 Right side surface, 44 Left side surface, 45 Front surface, 46 Back surface, 100 Filter circuit, L1, L2 Coil.

Claims

1. A coil component comprising: a housing having a pair of first and second main surfaces opposing each other and four side surfaces connecting the first and second main surfaces; a first coil conductor disposed inside the housing, the first coil section having an opening, and first and second lead wires drawn from the first coil section; a second coil section disposed inside the housing, the second coil conductor having an opening that at least partially overlaps with the opening of the first coil section when viewed from the direction in which the first and second main surfaces face each other, and a third coil conductor having third and fourth lead wires drawn from the second coil section; and a discontinuous region formed in the housing.

2. The coil component according to claim 1, wherein the discontinuous region extends from a surface of at least one of the first coil section and the second coil section to a main surface or a side surface of the housing.

3. A coil component according to claim 1 or 2, wherein the discontinuous region extends perpendicular to a surface of the first coil portion or the second coil portion.

4. A coil component described in any one of claims 1 to 3, wherein the length from the surface of the first coil portion or the second coil portion in the discontinuous region to the main surface or side surface of the housing is longer than the length between the first coil portion and the second coil portion.

5. A coil component according to any one of claims 1 to 4, wherein the discontinuous region is formed in each of the first coil portion and the second coil portion.

6. A coil component according to any one of claims 1 to 5, wherein the second coil portion is arranged on the first main surface side and the first coil portion is arranged on the second main surface side, and the coil component has a first discontinuous region extending from the first main surface side surface of the second coil portion to the first main surface, and a second discontinuous region extending from the second main surface side surface of the first coil portion to the second main surface.

7. A coil component as described in claim 6, wherein the first lead-out wire, the second lead-out wire, the third lead-out wire, and the fourth lead-out wire are led out to the second main surface side of the housing and include electrodes for mounting on the second main surface side, and the length of the first discontinuous region is shorter than the length of the second discontinuous region.

8. A coil component according to any one of claims 1 to 7, wherein the first coil portion and the second coil portion are substantially rectangular, and the discontinuous region is provided at at least one corner of the first coil portion or the second coil portion.

9. A coil component according to any one of claims 1 to 8, wherein the opening width of the contact point between the discontinuous region and the first coil portion or the second coil portion is narrower than the width of the first coil portion or the second coil portion.

10. A coil component as described in any one of claims 1 to 9, wherein the first and second lead-out wires are drawn out from a first position on a first side of the housing where the distance between them narrows, and the third and fourth lead-out wires are drawn out from a second position on a second side of the housing where the distance between them narrows, and the coil component is provided with a third discontinuous region extending from a surface of the first coil portion to at least one of the third side of the housing or the fourth side of the housing, and a fourth discontinuous region extending from a surface of the second coil portion to at least one of the third side of the housing or the fourth side.

11. The coil component according to claim 1, wherein the discontinuous region penetrates from the first main surface to the second main surface.

12. The coil component according to claim 1, wherein the discontinuous region extends from one of the first main surface or the second main surface to a position midway through the other main surface.

13. A coil component as described in claim 1, wherein the first coil portion and the second coil portion are arranged in parallel and inclined with respect to the first main surface when viewed from the side of the housing, and the discontinuous region extends perpendicularly from at least one of the first main surface or the second main surface to the surface of the first coil portion or the surface of the second coil portion.

14. A filter circuit comprising: the coil component according to any one of claims 1 to 13; and a capacitor connected to the coil component.

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