inductor

Abstract

To realize a structure capable of reducing the DC resistance of an inductor.SOLUTION: An inductor is equipped with an element assembly including a coil conductor that has a wound portion around which a conducting wire is wound, and a core having the coil conductor embedded. The element assembly is a generally rectangular parallelepiped, and has a pair of main surfaces opposite to each other, a pair of side surfaces adjacent to the main surfaces and opposite to each other, and two end surfaces adjacent to the main surfaces and the side surfaces and opposite to each other. Two lead-out portions respectively led out from two lead-out points on an outer peripheral portion of the wound portion respectively have transition parts connecting the lead-out points and exposed points exposed from the two end surfaces of the element assembly, and exposed parts exposed from the end surfaces. The two exposed parts are respectively connected to external electrodes, and at least one exposed point is located at a position where a tangent line of the outer periphery of the wound portion at the lead-out point is sandwiched between the exposed point and the wound portion when viewed from a normal direction of the main surface.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an inductor. [Background technology]

[0002] Patent Document 1 discloses a surface-mount inductor having an element body (molded body) in which a coil conductor formed by winding a conducting wire is embedded in a core containing magnetic powder and resin. The coil conductor is embedded so that the surface of the lead-out end (hereinafter referred to as the lead-out portion) of the coil conductor is exposed on the surface of the element body. After laser irradiation or the like is performed on the portion of the element body surface where the lead-out portion is exposed, external terminals are formed by plating. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-058418 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a problem in that the DC resistance of the inductor tends to increase as the length of the coil conductor between the winding portion and the portion of the lead-out portion that is exposed from the surface of the element body increases.

[0005] The present invention aims to realize a configuration that can reduce the DC resistance of an inductor. [Means for solving the problem]

[0006] One aspect of the present invention comprises an element body including a coil conductor having a winding portion around which a conducting wire is wound, and a core in which the coil conductor is embedded, the element body being a substantially rectangular parallelepiped having a pair of opposing main surfaces, a pair of side surfaces adjacent to the main surfaces and opposing each other, and two end surfaces adjacent to the main surfaces and the side surfaces and opposing each other, two lead-out portions led out from two lead-out points on the outer periphery of the winding portion each have a transition portion connecting the lead-out point and an exposed point exposed from the two end surfaces of the element body, and an exposed portion exposed from the end surfaces, the two exposed portions being connected to external electrodes, and when viewed from a normal direction to the main surfaces, a tangent to the outer periphery of the winding portion at each lead-out point passes between the exposed point and the winding portion and intersects with the end surfaces, For each of the pull-out portions, a first angle formed by two straight lines connecting the exposed point and the pull-out point with each other when viewed from the normal direction of the main surface is equal to or greater than 75 degrees and less than 180 degrees, and is larger than a second angle formed by two tangents to the outer periphery of the winding portion at the two pull-out points with each other when viewed from the normal direction of the main surface. It is an inductor. Another aspect of the present invention comprises an element body including a coil conductor having a winding portion around which a conducting wire is wound, and a core in which the coil conductor is embedded, the element body being a substantially rectangular parallelepiped having a pair of opposing main surfaces, a pair of side surfaces adjacent to and opposing the main surfaces, and two end surfaces adjacent to and opposing the main surfaces and the side surfaces, two lead-out portions led out from two lead-out points on the outer periphery of the winding portion each have a transition portion connecting the lead-out point and an exposed point exposed from the two end surfaces of the element body, and an exposed portion exposed from the end surfaces, and the two exposed portions are each of the lead-out points is connected to an external electrode, and when viewed from the normal direction to the main surface, a tangent to the outer periphery of the winding portion at each of the lead-out points passes between the exposed point and the winding portion and intersects with the end face, and an angle formed by a line connecting the exposed point and the lead-out point with a tangent to the outer periphery of the winding portion at the lead-out point, when viewed from the normal direction to the main surface, for one of the lead-out points is different from an angle formed by a line connecting the exposed point and the lead-out point with a tangent to the outer periphery of the winding portion at the lead-out point, when viewed from the normal direction to the main surface, for the other lead-out portion. [Effects of the Invention]

[0007] According to the present invention, it is possible to realize a configuration that can reduce the DC resistance of an inductor. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of an inductor according to an embodiment of the present invention, viewed from above; [Figure 2] FIG. 2 is a perspective view of the inductor as viewed from the bottom side. [Figure 3] FIG. 2 is a perspective view showing the internal configuration of an inductor. [Figure 4] 1A to 1C are schematic diagrams illustrating a manufacturing process of an inductor. [Figure 5] FIG. 2 is a plan view of the coil conductor as viewed from the top side. [Figure 6] 3 is a cross-sectional view of a main part of a coil conductor in a cross section parallel to a main surface. FIG. [Figure 7] FIG. 2 is a side view of the inductor as viewed from the end face side. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of the inductor according to this embodiment as viewed from the top surface 12 side, and FIG. 2 is a perspective view of the inductor as viewed from the bottom surface 10 side. The inductor of this embodiment is configured as a surface-mount electronic component, and includes an element body 2 having an approximately rectangular parallelepiped shape, which is one form of an approximately hexahedral shape, and a pair of external electrodes 4 provided on the surface of the element body 2.

[0010] Hereinafter, in the element body 2, the first main surface that faces the mounting board (not shown) during mounting is defined as the bottom surface 10, the second main surface opposite the bottom surface 10 is called the top surface 12, a pair of third surfaces that are perpendicular to the bottom surface 10 are called end surfaces 14, and a pair of fourth surfaces that are perpendicular to the bottom surface 10 and the pair of end surfaces 14 are called side surfaces 16. As shown in FIG. 1, the distance from the bottom surface 10 to the top surface 12 is defined as the thickness T of the element body 2, the distance between a pair of side surfaces 16 is defined as the width W of the element body 2, and the distance between a pair of end surfaces 14 is defined as the length L of the element body 2. The direction of the thickness T is defined as the thickness direction DT, the direction of the width W is defined as the width direction DW, and the direction of the length distance is defined as the length direction DL. The thickness direction DT is the normal direction to the top surface 12 and the bottom surface 10. The width direction DW is the normal direction to the side surfaces 16. The length direction DL is the normal direction to the end surfaces 14. The inductor has a length L of 2.0 mm, a width W of 1.6 mm, and a thickness T of 1.1 mm, for example.

[0011] FIG. 3 is a perspective view showing the internal configuration of the inductor. The element body 2 includes a coil conductor 20 and a core 30 having a substantially hexahedral shape in which the coil conductor 20 is embedded, and is configured as a molded inductor in which the coil conductor 20 is sealed in the core 30.

[0012] The core 30 is a molded body obtained by compressing and molding a powder mixture of magnetic particles and resin into a substantially hexahedral shape by applying pressure and heat while the coil conductor 20 is enclosed therein.

[0013] The magnetic particles of this embodiment include particles of two particle sizes: first magnetic particles that are large particles with a relatively large average particle size, and second magnetic particles that are small particles with a relatively small average particle size. As a result, during compression molding, the second magnetic particles, which are small particles, enter between the first magnetic particles, which are large particles, together with the resin, thereby increasing the filling rate of the magnetic particles in the core 30 and also increasing the magnetic permeability. In this embodiment, the average particle sizes of the metal particles of the first and second magnetic particles are 24.4 μm and 1.7 μm, respectively. The average particle size of the first magnetic particles is preferably 7 μm to 60 μm, and the average particle size of the second magnetic particles is preferably 1 μm to 4 μm. Furthermore, the magnetic particles may contain particles with different average particle sizes from the first and second magnetic particles, resulting in particles of three or more different particle sizes.

[0014] The first and second magnetic particles are both particles having a metal particle and an insulating film covering the surface of the metal particle, the insulating film having a thickness of several nanometers to several tens of nanometers. By covering the metal particle with the insulating film, the insulation resistance and the withstand voltage are increased. The first magnetic particles of this embodiment use Fe-Si-B amorphous alloy powder as the metal particles and zinc phosphate glass with a thickness of 10 nm to 50 nm as the insulating film, while the second magnetic particles of this embodiment use carbonyl iron powder as the metal particles and a silica film with a thickness of 5 nm to 15 nm as the insulating film.

[0015] In the mixed powder of this embodiment, the resin material is an epoxy resin containing a phenol alkyl type epoxy resin as a main component. In this embodiment, the mixed powder has a composition of 75±10 wt% first magnetic particles, 25±10 wt% second magnetic particles, and 2.7 wt% to 3.5 wt% resin.

[0016] As shown in FIG. 3, the coil conductor 20 includes a winding portion 22 around which a conductive wire 20a is wound, and a pair of lead-out portions 24 that are led out from the winding portion 22. The coil conductor 20 is composed of a conductive wire 20a and a coating layer formed on the surface of the conductive wire. The conductive wire 20a is a copper strip-shaped conductive wire (so-called flat wire) with a rectangular cross section, and its thickness is 18 μm to 90 μm, and its width is 240 μm to 340 μm. The coating layer is composed of an insulating layer 20b formed on the surface of the strip-shaped conductive wire, and a bonding layer 20c formed on the surface of the insulating layer 20b to bond the overlapping strip-shaped conductive wires together in the winding portion 22. The insulating layer 20b is made of polyimide amide resin and has a thickness of 6±2 μm. The bonding layer 20c is made of polyimide resin and has a thickness of 2.5±1.0 μm. The thickness surface of the coil conductor may be curved, and the width of the conductive wire includes the curved portion of the thickness.

[0017] The winding portion 22 of the coil conductor 20 is formed by spirally winding a conductor wire 20a (hereinafter simply referred to as a conductor wire) with both ends drawn out to the outer periphery and connected to each other at the inner periphery. Inside the element body 2, the coil conductor 20 is embedded in the core 30 with the central axis of the winding portion 22 oriented along the thickness direction DT of the element body 2. The drawn-out portions 24 are drawn out from the winding portion 22 to each of a pair of end faces 14, with one main surface exposed from the element body 2 and the other main surface embedded in the element body 2. The one main surface of the drawn-out portion 24 exposed from the element body 2 is electrically connected to the external electrode 4.

[0018] The pair of external electrodes 4 are so-called L-shaped electrodes, consisting of L-shaped members extending from each of the end faces 14 of the element body 2 to the bottom face 10. Each of the external electrodes 4 is connected to the lead-out portion 24 of the coil conductor 20 at the end face 14, and the portion 4A (FIG. 2) extending to the bottom face 10 is electrically connected to wiring on the circuit board by an appropriate mounting means such as solder.

[0019] An element body protective layer (not shown) is formed on the surface of the element body 2 excluding the area of ​​the external electrodes 4. The element body protective layer is made of, for example, phenoxy resin and novolac resin, and contains nanosilica as a filler. The element body protective layer is formed on the surface of the element body 2 to a thickness of 10 μm or more and 30 μm or less.

[0020] Inductors with such a configuration can improve DC bias characteristics by using a soft magnetic material for the magnetic particles, and are therefore used as electronic components in electric circuits through which large currents flow, as choke coil conductors in DC-DC converter circuits and power supply circuits, and as electronic components in electronic devices such as personal computers, DVD players, digital cameras, TVs, mobile phones, smartphones, car electronics, medical and industrial machinery, etc. However, the uses of inductors are not limited to these, and they can also be used in tuning circuits, filter circuits, rectifying and smoothing circuits, etc.

[0021] FIG. 4 is a schematic diagram of the inductor manufacturing process. As shown in the figure, the manufacturing process of an inductor includes a coil conductor forming step, a preform forming step, a thermoforming and hardening step, a barrel polishing step, and an external electrode forming step.

[0022] The coil conductor forming process is a process of forming the coil conductor 20 from the conductive wire 20a. In this process, the coil conductor 20 is formed into a shape having the above-mentioned winding portion 22 and a pair of lead-out portions 24 by winding the conductive wire 20a using a winding method called "alpha winding." Alpha winding refers to a state in which the conductive wire 20a, which functions as a conductor, is wound in two stages in a spiral shape so that the lead-out portions 24 at the beginning and end of the winding are located on the outer periphery. The number of turns of the coil conductor 20 is not particularly limited.

[0023] The preform forming step is a step of forming a preform called a tablet. The preform is formed by pressing the above-mentioned mixed powder, which is the material of the base body 2, into a solid form that is easy to handle.In this embodiment, two types of tablets are formed: a first tablet of an appropriate shape (e.g., E-shaped) with a groove into which the coil conductor 20 fits, and a second tablet of an appropriate shape (e.g., I-shaped or plate-shaped) that covers the groove of the first tablet.

[0024] In the thermoforming and curing process, the first tablet, the coil conductor, and the second tablet are placed in a molding die, and while applying heat, pressure is applied in the overlapping direction of the first tablet and the second tablet, and they are cured to integrate the first tablet, the coil conductor, and the second tablet, thereby forming the element body 2 in which the coil conductor 20 is enclosed in the core 30.

[0025] The barrel polishing step is a step of barrel polishing this molded body, and by this step, the corners of the element body 2 are rounded.

[0026] The external electrode forming step is a step of forming the external electrodes 4 on the core 30, and includes an element body protective layer forming step, a surface treatment step, and a plating layer forming step.

[0027] The element protection layer forming step is a step in which the entire surface of this molded body is coated with an insulating resin.

[0028] The surface treatment process is a process of modifying the surface of the planned electrode area by irradiating the area with laser light. Here, the planned electrode area refers to the area on the surface of the core 30 where the external electrode 4 is to be formed, including the area where the lead portion 24 is exposed. Specifically, by irradiating the laser light, the element body protective layer on the surface of the core 30 and the coating layer on the lead portion 24 of the coil conductor 20 are removed in the planned electrode area, the resin on the surface of the core 30 is removed, and the insulating film on the surface of the magnetic particles exposed from the core 30 is removed. As a result, the exposed area of ​​the metal of the magnetic particles per unit area of ​​the surface of the core 30 is larger in the planned electrode area than in other surface areas of the core 30. Note that after the laser irradiation, a cleaning process (e.g., etching process) may be performed to clean the surface of the planned electrode area.

[0029] In the plating layer forming step, a copper plating layer is formed at the electrode locations irradiated with the laser light by barrel plating copper on the surface of the core 30. In addition, the plating layer may be formed by further providing a Ni plating layer and a Sn plating layer on the copper plating layer.

[0030] By the external electrode forming step, the external electrodes 4 made of the plating layers are formed. The external electrode 4 is not limited to an L-shaped electrode, but may be a so-called five-sided electrode that is provided over the entire end face 14 and over a portion of each of the bottom face 10, the top face 12, and a pair of side faces 16 that are adjacent to the end face 14. When the five-sided electrode is applied by immersion in a conductive resin, the element protection layer forming step is not necessarily required.

[0031] 5 is a plan view of the coil conductor 20 as viewed in the thickness direction DT. That is, FIG. 5 shows the coil conductor 20 as viewed in a direction along the central axis of the coil conductor 20. In the following description, the two end faces 14 will be distinguished and referred to as end faces 14a and 14b, respectively. In addition, the two lead-out portions 24 will be distinguished and referred to as lead-out portions 24a and 24b, respectively.

[0032] As shown in FIG. 5, the lead-out portions 24a and 24b include transition portions 24a1 and 24b1 and exposed portions 24a2 and 24b2. The transition portions 24a1 and 24b1 are portions of the lead-out portions 24a and 24b that are drawn out from the arc-shaped curved portions at the outer periphery of the winding portion 22. The transition portions 24a1 and 24b1 extend from the points where the transition portions 24a1 and 24b1 are drawn out from the winding portion 22 to the end faces 14a and 14b. In other words, the transition portions 24a1 and 24b1 connect the winding portion 22 and the exposed portions 24a2 and 24b2. The lengths of the transition portions 24a1 and 24b1 affect the DC resistance of the inductor 1. That is, the shorter the lengths of the transition portions 24a1 and 24b1, the lower the DC resistance of the coil conductor 20, and therefore the lower the DC resistance of the inductor 1.

[0033] The exposed portions 24a2 and 24b2 are portions of the lead-out portions 24a and 24b that are exposed from the end faces 14a and 14b, respectively. The exposed portions 24a2 and 24b2 are formed by bending portions of the lead-out portions 24a and 24b on the tip ends 24a3 and 24b3 sides, respectively, in a direction that follows the curvature of the winding portion 22. The exposed portions 24a2 and 24b2 extend along the end faces 14a and 14b. The exposed portions 24a2 and 24b2 are each covered by the external electrode 4. The exposed portions 24a2 and 24b2 affect the DC resistance of the inductor 1. That is, the larger the area of ​​the exposed portions 24a2 and 24b2 exposed from the end faces 14a and 14b, the lower the DC resistance between the external electrode 4 and the coil conductor 20, and therefore the lower the DC resistance of the inductor 1. Furthermore, the larger the area of ​​the exposed portions 24a2, 24b2 exposed from the end faces 14a, 14b, the stronger the connection between the external electrode 4 and the coil conductor 20 becomes.

[0034] Hereinafter, the points at which the transition portions 24a1 and 24b1 are pulled out from the winding portion 22 are referred to as pull-out points Da and Db. The pull-out points Da and Db are points at the ends of the transition portions 24a1 and 24b1 on the winding portion 22 side. As shown in FIG. 3, the winding portion 22 is wound in two stages in the thickness direction, with the pull-out portion 24a being pulled out from the upper stage of the winding portion 22 and the pull-out portion 24b being pulled out from the lower stage of the winding portion 22. In FIG. 5, the lower stage of the winding portion 22 is located further back than the upper stage of the winding portion 22, so the outline of the conductor 20a near the pull-out point Db is shown with a dashed line. The points at which the exposed portions 24a2 and 24b2 begin to be exposed from the end faces 14a and 14b are referred to as exposed points Ea and Eb, respectively. The exposed points Ea and Eb are points at the ends of the transition portions 24a1 and 24b1 on the tip ends 24a3 and 24b3 of the drawn-out portions 24a and 24b, and are points at the ends of the exposed portions 24a2 and 24b2 on the winding portion 22 side. Detailed definitions of the drawn-out points Da and Db and the exposed points Ea and Eb will be described later.

[0035] Figure 5 shows tangent lines L3 and L4 at pull-out points Da and Db to the outer periphery of winding portion 22. Figure 5 also shows a straight line L1 connecting pull-out point Da and exposed point Ea, and a straight line L2 connecting pull-out point Db and exposed point Eb.

[0036] As shown in FIG. 5, transition portions 24a1, 24b1 of lead-out portions 24a, 24b bend in a direction away from winding portion 22 near lead-out points Da, Db. In other words, transition portions 24a1, 24b1 bend in a direction opposite to the curvature of winding portion 22 near lead-out points Da, Db. Therefore, transition portion 24a1 extends in an angular direction that is more open toward end face 14a than tangent line L3. Furthermore, transition portion 24b1 extends in an angular direction that is more open toward end face 14b than tangent line L4. Transition portions 24a1, 24b1 are bent in the coil conductor forming step by bending lead-out portions 24a, 24b led out from winding portion 22 in a direction away from winding portion 22, i.e., in a direction opposite to the winding direction of winding portion 22.

[0037] Because the transition portion 24a1 extends in an angle direction more open toward the end surface 14a than the tangent line L3, the exposed point Ea is located at a point sandwiched between the tangent line L3 and the winding portion 22 when viewed from the thickness direction DT. Similarly, because the transition portion 24b1 extends in an angle direction more open toward the end surface 14b than the tangent line L4, the exposed point Eb is located at a point sandwiched between the tangent line L4 and the winding portion 22 when viewed from the thickness direction DT. As a result, the distance between the exposed point Ea and the pull-out point Da is shorter than the distance between the pull-out point Da and the intersection point Ea1. Here, the intersection point Ea1 is the point where the exposed portion 24a2 and the tangent line L3 intersect when viewed from the thickness direction DT. Similarly, the distance between the exposed point Eb and the pull-out point Db is shorter than the distance between the pull-out point Db and the intersection point Eb1. Here, the intersection point Ea2 is the point where the exposed portion 24b2 intersects with the tangent line L4 when viewed from the thickness direction DT. Therefore, the lengths of the transition portions 24a1 and 24b1 are shortened.

[0038] More specifically, when viewed from the thickness direction DT, the transition portion 24a1 extends in a direction that opens toward the end surface 14a by an angle A3 from the tangent line L3. When viewed from the thickness direction DT, a straight line L1 connecting the lead-out point Da and the exposed point Ea intersects with the tangent line L3 at an angle A3. When viewed from the thickness direction DT, the transition portion 24b1 extends in a direction that opens toward the end surface 14b by an angle A4 from the tangent line L4. When viewed from the thickness direction DT, a straight line L2 connecting the lead-out point Db and the exposed point Eb intersects with the tangent line L4 at an angle A4. In this embodiment, the angles A3 and A4 are each greater than 0 degrees and may be different from each other.

[0039] 5, the lines L1 and L2 intersect at a first angle A1 when viewed in a direction along the central axis of the coil conductor 20. As described above, the transition portions 24a1 and 24b1 extend at angles that are wider toward the end faces 14a and 14b than the tangents L3 and L4, respectively. Therefore, the first angle A1 is greater than the second angle A2, which is the angle between the tangents L3 and L4 when viewed in a direction along the central axis of the coil conductor 20.

[0040] The larger the first angle A1, the more the transition portions 24a1, 24b1 open toward the end faces 14a, 14b. Therefore, the larger the first angle A1, the shorter the transition portions 24a1, 24b1. Furthermore, the larger the first angle A1, the longer the exposed portions 24a2, 24b2. However, the larger the first angle A1, the larger the angle at which the lead portions 24a, 24b are bent toward the curvature direction of the winding portion when forming the exposed portions 24a2, 24b2, making processing of the coil conductor 20 more difficult. Therefore, it is desirable that the first angle A1 be greater than or equal to 75 degrees and less than 180 degrees. It is even more desirable that the first angle A1 be greater than or equal to 85 degrees and less than or equal to 105 degrees. In this embodiment, the first angle A1 is 95 degrees.

[0041] FIG. 6 is a cross-sectional view of a main part of the coil conductor 20 in a cross section parallel to the upper surface 12, showing the vicinity of the lead-out point Da. 6, as the lead-out portion 24a is drawn out from the winding portion 22, a peeled portion 23, which is a wedge-shaped gap, is formed between the lead-out portion 24a and the winding portion 22. The mixed powder that forms the core 30 is filled in the peeled portion 23. The peeled portion 23 is formed by bifurcating the fusion layer 20c between the conductor 20a and the coating layer on the outer periphery of the winding portion 22 and the conductor 20a and the coating layer in the transition portion 24a1.

[0042] As described above, the pull-out point Da is the point where the transition portion 24a1 is pulled out from the winding portion 22, but a more specific definition of the pull-out point Da is the point on the conductor 20a on the outer periphery of the winding portion 22 that is closest to the tip 23a of the peeling portion 23. The position of the pull-out point Da can be considered to be the position of the point on the conductor 20a on the outer periphery of the winding portion 22 that is closest to the tip 23a of the peeling portion 23 in any cross section parallel to the top surface 12 that includes the winding portion 22 and the pull-out portion 24a.

[0043] As described above, tangent line L3 is a tangent to the outer periphery of winding portion 22 at lead-out point Da. More specifically, tangent line L3 is a tangent to conductor 20a at lead-out point Da. Tangent line L3 is identified in a perspective view of inductor 1 from the normal direction of top surface 12, or in any cross-sectional view parallel to top surface 12 that includes winding portion 22 and lead-out portion 24a.

[0044] Like lead-out point Da, lead-out point Db is a point on conductor 20a on the outer periphery of winding portion 22 that is closest to tip 23a of peeling portion 23 formed between lead-out portion 24b and winding portion 22. Also, like tangent line L3, tangent line L4 is a tangent line to conductor 20a at lead-out point Db.

[0045] FIG. 7 is a side view of the inductor 1 as viewed from the end face 14a side. As shown in FIG. 7, exposed point Ea is the point on exposed portion 24a2 that is the farthest from tip 24a3 of lead portion 24a in the normal direction of side surface 16.

[0046] 7, exposed portion 24a2 preferably crosses bisector Cw of end face 14a, which passes through the bisecting point of sides 13a and the bisecting point of sides 13b, when viewed in the longitudinal direction DL. In other words, tip 24a3 of lead-out portion 24a is preferably located at a position sandwiching bisector Cw between tip 24a3 and exposed point Ea when viewed in the longitudinal direction DL. This shortens the length of the conductor connecting winding portion 22 to exposed portion 24a2, thereby reducing the DC resistance of inductor 1.

[0047] As described above, the larger the area of ​​the exposed portions 24a2, 24b2 exposed from the end faces 14a, 14b, the lower the DC resistance of the inductor 1 and the stronger the connection between the external electrode 4 and the coil conductor 20. Therefore, it is desirable that the length W1 of the exposed portions 24a2, 24b2 be as long as possible. To reduce the DC resistance of the inductor 1 and strengthen the connection between the external electrode 4 and the coil conductor 20, specifically, it is desirable that the length W1 be between 1 / 7 and 1 / 2 of the width W between the pair of side faces 16. If the length W1 is less than 1 / 7, the DC resistance of the inductor 1 will be adversely affected, and if it is more than 1 / 2, it will be difficult to set the coil conductor 20 in a mold.

[0048] Like exposed point Ea, exposed point Eb is the point on exposed portion 24b2 that is farthest from tip 24b3 of drawn-out portion 24b in the direction normal to side surface 16. Like exposed portion 24a2, exposed portion 24b2 desirably crosses the bisector of end surface 14b that passes through the bisecting point of the side between top surface 12 and end surface 14b and the bisecting point of the side between bottom surface 10 and end surface 14b when viewed from the longitudinal direction DL. Like exposed portion 24a2, the length of exposed portion 24b2 in the direction along the side between top surface 12 and end surface 14b and the side between bottom surface 10 and end surface 14b is desirably between 1 / 7 and 1 / 2 of the width W between the pair of side surfaces 16.

[0049] [Other embodiments] In the above-described embodiment, the inductor 1 is shown as an example, but the present invention can be similarly applied to any electronic component other than an inductor that includes a wiring layer having a structure similar to that of the coil conductor 20.

[0050] Furthermore, in the above-described embodiment, the peeled portion 23 is formed by bifurcating the fusion layer 20c, but this is not limitative of the peeled portion 23. The peeled portion 23 may be any portion of the gap formed between the conductor 20a on the outer periphery of the winding portion 22 and the conductor 20a in the transition portions 24a1 and 24b1, which may be filled with the mixed powder of the core 30 or may be a void.

[0051] In the above-described embodiment, angle A3, which is the angle between straight line L1 and tangent line L3, is the same as angle A4, which is the angle between straight line L2 and tangent line L4. However, the configuration of angles A3 and A4 is not limited to this. For example, angle A3 may be larger than angle A4. Also, angle A3 may be smaller than angle A4. That is, angle A3 and angle A4 may be different angles in inductor 1, and lead-out portion 24a and lead-out portion 24b may be asymmetric.

[0052] In the above-described embodiment, the transition portion 24a1 extends at an angle relative to the tangent line L3 toward the end face 14a, and the transition portion 24b1 extends at an angle relative to the tangent line L4 toward the end face 14b. However, the configuration of the transition portions 24a1 and 24b1 is not limited to this. For example, the transition portion 24a1 may extend at an angle relative to the tangent line L3 toward the end face 14a, and the transition portion 24b1 may extend at an angle relative to the tangent line L4 toward the end face 14b. That is, it is sufficient that at least one of the two transition portions 24a1 and 24b1 extends at an angle relative to the tangent lines L3 and L4 toward the end faces 14a and 14b. In this case, one of the two exposed points Ea and Eb is located on the tangent lines L3 and L4 or closer to the winding portion 22 than the tangent lines L3 and L4, and the other is located on the side of the tangent lines L3 and L4 away from the winding portion 22.

[0053] In the above-described embodiment, both exposed portions 24a2 and 24b2 cross the bisector of the end faces 14a and 14b in the width direction DW when viewed from the length direction DL. However, the configuration of exposed portions 24a2 and 24b2 is not limited to this. For example, when viewed from the length direction DL, one of exposed portions 24a2 and 24b2 may cross the bisector of the end faces 14a and 14b in the width direction DW, while the other may not. Furthermore, exposed portions 24a2 and 24b2 may not be parallel to the width direction DW, but may be inclined. The inclination is preferably 15 degrees or less.

[0054] Furthermore, the features and configurations shown in the above-described embodiments and modifications can be used in combination with each other in any electronic component. For example, the electronic component can include any combination of the above-described inductors.

[0055] All of the above-described embodiments and modifications are merely examples of one aspect of the present invention, and any modifications and applications are possible within the scope of the present invention. Furthermore, unless otherwise specified, the horizontal, vertical, and other directions, various numerical values, shapes, and materials in the above-described embodiments include a range (so-called equivalent range) that produces the same effect as those directions, numerical values, shapes, and materials.

[0056] [Configuration supported by the above embodiment] The above-described embodiment supports the following configurations.

[0057] (Configuration 1) An inductor comprising: an element body including a coil conductor having a winding portion around which a conducting wire is wound; and a core in which the coil conductor is embedded, wherein the element body is a substantially rectangular parallelepiped and has a pair of opposing main surfaces, a pair of side surfaces adjacent to the main surfaces and opposing each other, and two end surfaces adjacent to the main surfaces and the side surfaces and opposing each other, wherein two lead-out portions led out from two lead-out points on the outer periphery of the winding portion each have a transition portion connecting the lead-out point and an exposed point exposed from the two end surfaces of the element body, and an exposed portion exposed from the end surfaces, wherein the two exposed portions are each connected to an external electrode, and at least one of the exposed points is located between the winding portion and a tangent to the outer periphery of the winding portion at the lead-out point, when viewed from the normal direction of the main surfaces. According to the inductor of configuration 1, the length of the lead-out portion, which connects the winding portion to the exposed portion, is shortened. This reduces the DC resistance of the inductor. Furthermore, since the exposed portion is formed long, the DC resistance between the external electrode and the exposed portion is reduced, thereby reducing the DC resistance of the inductor.

[0058] (Configuration 2) An inductor according to configuration 1, wherein the length of at least one of the exposed portions along the side between the main surface and the end face is greater than or equal to 1 / 7 and less than or equal to 1 / 2 of the distance between the two opposing side surfaces. According to the inductor of Configuration 2, the DC resistance between the exposed portion and the external electrode is reduced, thereby reducing the DC resistance of the inductor and strengthening the connection between the exposed portion and the external electrode.

[0059] (Configuration 3) An inductor according to configuration 1 or 2, wherein at least one of the exposed portions intersects the bisector of the end face that extends on the end face through the bisecting point of the side between the end face and the main surface. In the inductor of Configuration 3, the exposed portion and the external electrode are connected near the center of the end face, which shortens the length of the conductor connecting the winding portion to the exposed portion, thereby reducing the DC resistance of the inductor.

[0060] (Configuration 4) An inductor described in any one of configurations 1 to 3, wherein for each of the draw-out portions, a first angle formed by two straight lines connecting the exposed point and the draw-out point with each other when viewed from the normal direction of the main surface is greater than or equal to 75 degrees and less than 180 degrees, and is greater than a second angle formed by two tangents to the outer periphery of the winding portion at the two draw-out points with each other when viewed from the normal direction of the main surface. According to the inductor of Configuration 4, the length of the lead-out portion connecting the winding portion to the exposed portion is short, and the exposed portion is long, which reduces the DC resistance of the inductor.

[0061] (Configuration 5) The inductor according to configuration 4, wherein the first angle is equal to or greater than 85 degrees and equal to or less than 105 degrees. According to the inductor of configuration 5, the length of the lead-out portion connecting the winding portion to the exposed portion is short, and the exposed portion is long, which reduces the DC resistance of the inductor.

[0062] (Configuration 6) An inductor described in any one of configurations 1 to 5, wherein, for one of the pull-out portions, the angle that a straight line connecting the exposed point and the pull-out point makes with a tangent to the outer periphery of the winding portion at the pull-out point, when viewed from the normal direction of the main surface, is different from the angle that a straight line connecting the exposed point and the pull-out point makes with a tangent to the outer periphery of the winding portion at the pull-out point, when viewed from the normal direction of the main surface, for the other of the pull-out portions. According to the inductor of Configuration 6, the DC resistance of the inductor can be reduced even when the pair of lead-out portions are asymmetric with respect to each other. The difference in angle is, for example, 15 degrees or less. [Explanation of symbols]

[0063] 1 inductor 2 Base 4 External electrode 10 Bottom surface (main surface) 12 Top surface (main surface) 14 End face 14a End face 14b End face 16 Side 20 Coil conductor 20a conductor 22 Winding section 24 Drawer section 24a Drawer part 24a1 Transition section 24a3 Tip 24b Drawer part 24b1 Transition section 24b3 Tip 30 cores A1 First angle A2 2nd angle A3 angle A4 angle Cw bisector Da withdrawal point Db withdrawal point Ea exposure point Eb exposure point

Claims

1. The coil conductor has a winding portion around which a conducting wire is wound, and the coil conductor is embedded in a core. the element body is a substantially rectangular parallelepiped and has a pair of opposing main surfaces, a pair of side surfaces adjacent to the main surfaces and opposing each other, and two end surfaces adjacent to the main surfaces and the side surfaces and opposing each other; two pull-out portions pulled out from two pull-out points on the outer periphery of the winding portion, respectively, each have a transition portion connecting the pull-out point and an exposed point exposed from the two end faces of the element body, and an exposed portion exposed from the end face, the two exposed portions are connected to external electrodes, When viewed from a normal direction of the main surface, a tangent to an outer periphery of the winding portion at each of the pull-out points passes between the exposed point and the winding portion and intersects with the end surface, For each of the pull-out portions, a first angle formed by two straight lines connecting the exposed point and the pull-out point with each other when viewed from the normal direction of the main surface is equal to or greater than 75 degrees and less than 180 degrees, and is larger than a second angle formed by two tangents to the outer periphery of the winding portion at the two pull-out points with each other when viewed from the normal direction of the main surface. Inductor.

2. An element body including a coil conductor having a winding portion around which a conducting wire is wound, and a core in which the coil conductor is embedded, the element body is a substantially rectangular parallelepiped and has a pair of opposing main surfaces, a pair of side surfaces adjacent to the main surfaces and opposing each other, and two end surfaces adjacent to the main surfaces and the side surfaces and opposing each other; two pull-out portions pulled out from two pull-out points on the outer periphery of the winding portion, respectively, each have a transition portion connecting the pull-out point and an exposed point exposed from the two end faces of the element body, and an exposed portion exposed from the end face, the two exposed portions are connected to external electrodes, When viewed from a normal direction of the main surface, a tangent to an outer periphery of the winding portion at each of the pull-out points passes between the exposed point and the winding portion and intersects with the end surface, With respect to one of the pull-out portions, the angle formed by a line connecting the exposed point and the pull-out point and a tangent to the outer periphery of the winding portion at the pull-out point when viewed from the normal direction of the main surface is: With respect to the other of the pull-out portions, a straight line connecting the exposed point and the pull-out point forms an angle different from an angle formed with a tangent to an outer periphery of the winding portion at the pull-out point when viewed from the normal direction of the main surface. Inductor.

3. a length of each of the exposed portions along a side between the main surface and the end surface is equal to or greater than 1 / 7 and equal to or less than 1 / 2 of a distance between the two opposing side surfaces; 3. The inductor according to claim 1 or 2.

4. Each of the exposed portions crosses a bisector of the end surface, the bisector passing through a bisecting point of a side between the end surface and the main surface and extending on the end surface.

3. The inductor according to claim 1 or 2.

5. The first angle is equal to or greater than 85 degrees and equal to or less than 105 degrees.

10. The inductor of claim 1.

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