inductor

Abstract

To reduce variation in a position on an element assembly end face and an exposure area, of a drawn part drawn out from a winding part of a coil conductor embedded in the element assembly.SOLUTION: An inductor includes an element assembly including a coil conductor and a core which embeds the coil conductor and contains magnetic particles and a resin, and an external electrode arranged on facing end faces of the element assembly, wherein the coil conductor includes a winding part where a conducting wire is wound around a winding shaft, a drawn part drawn out from the winding part, and an external electrode connection part that is connected to the drawn part and is a part of the conducting wire for being connected to the external electrode, a boundary between the drawn part and the external electrode connection part is a bent part where the conducting wire is bent, in plan view when the upper face perpendicular to the end faces of the element assembly is viewed from a normal direction, a first angle formed by an extension direction of the external electrode connection part extending with the bent part as a starting point and a normal direction of the end faces passing through the bent part toward inside the element assembly is larger than 90 degrees.SELECTED DRAWING: Figure 10

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a wire-wound inductor consisting of an element body including a core containing magnetic particles and a coil conductor embedded in the core, and external electrodes provided on opposing end faces of the element body. The coil conductor consists of a winding part and lead-out parts drawn out from both ends of the winding part, and the lead-out parts are exposed from the end faces of the element body and connected to the external electrodes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Korean Patent Application Publication No. 10-2014-0038781 Summary of the Invention [Problem to be solved by the invention]

[0004] In an inductor having the above configuration, variations in the position and exposed area of ​​the lead-out portion on the end face of the element body may occur due to the shape of the entire coil conductor including the winding portion and the lead-out portion, the orientation of the coil conductor inside the element body, etc. Such variations in the position and exposed area of ​​the lead-out portion on the end face of the element body may cause variations in the electrical connection state between the lead-out portion and the external electrode, and may cause variations in the DC resistance value at the connection between the lead-out portion and the external electrode.

[0005] The object of the present invention is to reduce the variation in the position and exposed area of ​​the lead-out portion drawn out from the winding portion of the coil conductor at the end face of the element body in an inductor having an element body including a core containing magnetic particles and a coil conductor embedded in the core. [Means for solving the problem]

[0006] One aspect of the present invention comprises an element body including a coil conductor, a core including magnetic particles and a resin in which the coil conductor is embedded, and a pair of external electrodes arranged on each of a pair of opposing end faces of the element body, wherein the coil conductor includes a winding portion in which a conductor wire is wound around a winding axis, a pair of lead-out portions that are drawn from the winding portion to each of the end faces of the element body and are electrically connected to the external electrodes, and external electrode connection portions that are portions of the conductor wire that are connected to each of the lead-out portions and are for connection to each of the external electrodes, wherein the boundaries between the pair of lead-out portions and the pair of external electrode connection portions are bent portions where the conductor wire is bent, and Orthogonal a first angle formed by the extension direction of the external electrode connection portion starting from the bent portion and the normal direction of the end face toward the inside of the element body, the first angle being greater than 90 degrees and not greater than 100 degrees; a second angle formed by the extension direction of the lead portion starting from the bent portion and the extension direction of the external electrode connection portion starting from the bent portion, the second angle being greater than 150 degrees and less than 180 degrees; and the element body has upper surfaces that are opposed to each other perpendicular to the pair of opposed end faces of the element body. the coil conductor is embedded in the element body so that the winding axis is along the normal direction to the top surface, and the outline of the winding portion in a plan view seen from the normal direction to the top surface has a first length that is the maximum length in a direction perpendicular to the side surfaces and is equal to or greater than a second length that is the maximum length measured in a direction perpendicular to the end surfaces, and the side surfaces of the external electrode connection portions are exposed at the end surfaces of the element body and are electrically connected to the external electrodes. [Effects of the Invention]

[0007] According to the present invention, in an inductor having a base body including a core containing magnetic particles and a coil conductor embedded in the core, it is possible to reduce variations in the position and exposed area of ​​the lead-out portion drawn out from the winding portion of the coil conductor at the end face of the base body. [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 showing the internal configuration of an inductor. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. [Figure 7] FIG. 2 is a cross-sectional view of a conductor constituting a conducting wire. [Figure 8] 10A and 10B are diagrams illustrating the configuration of a winding portion of an inductor in which the winding portion of a coil conductor is wound in a normal winding manner. [Figure 9] 3A and 3B are diagrams illustrating a configuration of a winding part of an inductor according to the present embodiment. [Figure 10] 1A and 1B are diagrams showing the configuration of a coil conductor embedded in an element body. [Figure 11] FIG. 10 is a cross-sectional view taken along line XI-XI in FIG. 5. [Figure 12] 12 is a cross-sectional view corresponding to FIG. 11 when a normal conductor is used. [Figure 13] FIG. 2 is a side view of the inductor 1 as viewed from the end face 14 side. [Figure 14] FIG. 14 is a diagram schematically showing a cross section taken along line XIV-XIV in FIG. 13. [Figure 15] 14 is a cross-sectional view taken along the line XIV-XIV in FIG. 13. [Figure 16] 16 is a cross-sectional view taken along line XVI-XVI of FIG. 13. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] [Overall inductor configuration] FIG. 1 is a perspective view of an inductor 1 according to this embodiment as viewed from a top surface 12 side, and FIG. 2 is a perspective view of the inductor 1 as viewed from a bottom surface 10 side. The inductor 1 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.

[0011] 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 main surfaces that are perpendicular to the bottom surface 10 are called end surfaces 14, and a pair of fourth main surfaces that are perpendicular to the bottom surface 10 and the pair of end surfaces 14 are called side surfaces 16. 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. Furthermore, 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 nominal size of the inductor 1 as a finished product is, for example, a length L dimension of 1.4 mm, a width W dimension of 1.2 mm, and a thickness T dimension of 0.8 mm.

[0012] Hereinafter, a plane along the DL direction and DT direction (a plane perpendicular to the DW direction) will be referred to as an LT plane, a plane along the DT direction and DW direction (a plane perpendicular to the DL direction) will be referred to as a TW plane, and a plane along the DL direction and DW direction (a plane perpendicular to the DT direction) will be referred to as an LW plane. Also, cross sections of inductor 1 along the LT plane, TW plane, and LW plane will be referred to as the LT cross section, TW cross section, and LW cross section, respectively.

[0013] FIG. 3 is a perspective view showing the internal configuration of the inductor 1. As shown in FIG. 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.

[0014] 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.

[0015] The magnetic particles of this embodiment are made of a soft magnetic material and include particles of two different 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 size of the metal particles of the first magnetic particles is 20 μm or more and 28 μm or less, and the average particle size of the metal particles of the second magnetic particles is 1 μm or more and 6 μm or less. The average particle size of the first magnetic particles is preferably 20 μm or more and 22 μm or less, and the average particle size of the second magnetic particles is preferably 1.5 μm or more and 1.8 μm or less. Furthermore, the magnetic particles may contain particles with different average particle sizes from the first magnetic particles and the second magnetic particles, resulting in particles of three or more different particle sizes.

[0016] The first magnetic particles and the second magnetic particles are both particles having a metal particle, an oxide film covering the surface of the metal particle, and an insulating film covering the surface of the oxide film. By covering the metal particle with the oxide film and the insulating film, the insulation resistance and the withstand voltage are increased. In the first magnetic particles of this embodiment, Fe-Si-B amorphous alloy powder is used as the metal particles. The oxide film of the first magnetic particles is composed of two layers, an SiO layer and an Fe2SiO4 layer, and the total thickness of the oxide film is 20 nm to 155 nm. The insulating film of the first magnetic particles is made of phosphate glass and has a thickness of 10 nm to 100 nm.

[0017] In addition, in the second magnetic particles of this embodiment, carbonyl iron powder is used as the metal particles. The oxide film of the second magnetic particles is iron oxide formed by surface oxidation of carbonyl iron powder, which is a metal particle. Furthermore, the insulating film of the second magnetic particles is a sol-gel reaction product containing silica. This increases the slipperiness of the surface of the second magnetic particles, making it easier for the second magnetic particles to penetrate between the first magnetic particles during the element molding and curing process of the element body 2, which will be described later. As a result, the density of the magnetic material in the core 30 can be further increased, further increasing the relative permeability of the core 30.

[0018] In addition, in the first magnetic particles, the metal particles may be Fe-Si-Cr alloy powder, Fe-Ni-Al alloy powder, Fe-Cr-Al alloy powder, Fe-Si-Al alloy powder, Fe-Ni alloy powder, or Fe-Ni-Mo alloy powder. In the first magnetic particles, the insulating film may be made of phosphoric acid, zinc phosphate, manganese phosphate, glass, or resin.

[0019] The resin material contained in the mixed powder of this embodiment includes bisphenol A epoxy resin and rubber-modified epoxy resin, which allows the inductor 1 to be manufactured with improved element body 2 in both strength and toughness.

[0020] In this embodiment, the magnetic powder contained in the mixed powder is such that the first magnetic particles account for 70 wt% to 85 wt% and the second magnetic particles account for 15 wt% to 30 wt% of the total weight of the magnetic particles contained in the mixed powder. Furthermore, the resin contained in the mixed powder is 2.0 wt% to 3.5 wt% of the total weight of the magnetic powder and resin. The first magnetic particles are preferably 70 wt% to 80 wt%, and the second magnetic particles are preferably 20 wt% to 30 wt%. Furthermore, the resin is preferably 2.7 wt% to 30 wt%.

[0021] 3, the coil conductor 20 includes a winding portion 22 in which a conductor wire is wound spirally around a winding axis K in two upper and lower stages so that both ends are located on the outer periphery and are connected to each other on the inner periphery, a pair of lead-out portions 23 drawn out from the winding portion 22, and a pair of external electrode connecting portions 24 that are conductor wire portions connected to the lead-out portions 23, respectively, for connection to external electrodes described below. The winding portion 22 includes two winding regions 22a and 22b that overlap along the winding axis K. The conductor wires of the winding regions 22a and 22b are connected to each other at a portion of their inner peripheries.

[0022] The winding portion 22 has, for example, a substantially rectangular shape in plan view when viewed from the direction of the winding axis K. The coil conductor 20 is embedded in the element body 2 so that the winding axis K is along the thickness direction DT of the element body 2 and so that, in plan view when viewed from the direction of the winding axis K, each side of the winding portion 22, which has a substantially rectangular shape in plan view, is aligned with (e.g., parallel to) each side of the element body 2, which also has a substantially rectangular shape in plan view.

[0023] The conducting wire constituting the coil conductor 20 is composed of a conductor and a coating layer formed on the surface of the conductor. The conducting wire is a flat wire with a rectangular cross section, and the conductor is a strip-shaped conductor made of copper with a rectangular cross section. The conductor has a thickness of 60 μm to 100 μm and a width of 160 μm to 200 μm. The coating layer is composed of an insulating layer formed on the surface of the strip-shaped conducting wire and a fusion layer formed on the surface of the insulating layer for bonding the overlapping strip-shaped conducting wires together in the winding portion 22. The insulating layer is made of, for example, polyimide amide resin and has a thickness of 3 μm. The fusion layer is made of, for example, polyamide resin and has a thickness of 1 μm to 25 μm.

[0024] The lead-out portion 23 is drawn out from the winding portion 22 and is electrically connected to the external electrode 4 via the external electrode connecting portions 24 that are drawn out to and exposed on each of the pair of end faces 14 . 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 an external electrode connecting portion 24 of the coil conductor 20 at the end face 14, and a portion 4A (FIG. 2) extending to the bottom face 10 is electrically connected to wiring on a circuit board by an appropriate mounting means such as solder.

[0025] 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, for example, a resin in which phenoxy resin is added to 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. The thickness of the element body protective layer is preferably 10 μm or more and 20 μm or less, and more preferably 15 μm or less.

[0026] Inductor 1 with this configuration can improve DC bias characteristics by using a soft magnetic material for the magnetic particles, and is therefore used as an electronic component in electric circuits through which large currents flow, as a choke coil in DC-DC converter circuits and power supply circuits, and as an electronic component 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 inductor 1 are not limited to these, and it can also be used in, for example, tuning circuits, filter circuits, rectifying and smoothing circuits, etc.

[0027] [Inductor manufacturing process overview] FIG. 4 is a schematic diagram of the manufacturing process of the inductor 1. As shown in the figure, the manufacturing process of the inductor 1 includes a coil conductor forming step, a preform forming step, an element molding and hardening step, an element grinding step, and an external electrode forming step.

[0028] The coil conductor forming process is a process of forming the coil conductor 20 from a conductive wire. In this process, the coil conductor 20 is formed into a shape having the above-mentioned winding portion 22, lead-out portion 23, and external electrode connection portion 24 by winding the conductive wire using a winding method called "alpha winding." Alpha winding refers to a state in which the conductive wire, which functions as a conductor, is wound in two stages in a spiral shape so that the lead-out portions 23 at the start and end of the winding are located on the outer periphery. The number of turns of the coil conductor 20 is not particularly limited.

[0029] 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.

[0030] In the element molding and hardening process, the first tablet, the coil conductor, and the second tablet are set 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 hardened to integrate the first tablet, the coil conductor, and the second tablet, thereby molding the element 2 in which the coil conductor 20 is enclosed in the core 30.

[0031] In the element body grinding process, abrasive grains are applied to the side surfaces of the molded body obtained in the element body molding and hardening process to scrape off (i.e., grind) the side surfaces until the width W reaches a predetermined width. This process results in an element body 2 in which the width W of the molded body has been downsized to the predetermined width. This downsizing reduces the distance (also known as the side gap) between the coil conductor 20 in the element body 2 and the side surfaces of the element body 2, thereby increasing the radial coil occupancy rate of the winding portion 22 of the coil conductor 20. Furthermore, because the element body 2 is obtained by grinding the molded body obtained by compression molding to a predetermined size, dimensional variation in the element body 2 can be reduced compared to when the element body 2 is controlled to a predetermined size by compression molding alone. In the element body grinding process, polishing (e.g., barrel polishing) may be performed to chamfer corners created by grinding the side surfaces of the element body 2.

[0032] The external electrode forming step is a step of forming the external electrodes 4 on the element body 2, and includes an element body protective layer forming step, a surface treatment step, and a plating layer forming step.

[0033] The element body protective layer forming step is a step of coating the entire surface of the element body 2 with an insulating resin.

[0034] 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 external electrode connection portion 24 is exposed. Specifically, by irradiating the area with laser light, the element body protective layer on the surface of the element body 2 and the coating layer on the external electrode connection 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 light irradiation, a cleaning process (e.g., etching process) may be performed to clean the surface of the planned electrode area.

[0035] 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.

[0036] The inductor 1 of this embodiment will be further described in detail below.

[0037] [A. Coil conductor] Fig. 5 is a plan view showing the internal configuration of the inductor 1. Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5. Fig. 6 shows a cross-section of the inductor 1 taken along line TW. First, we will explain the coil conductor 20 used in the inductor 1. As described above, the coil conductor 20 includes the winding portion 22 around which a conducting wire is wound, a pair of lead-out portions 23, and a pair of external electrode connecting portions 24.

[0038] The left end of the winding portion 22 is drawn out from the lower stage of the winding portion 22, which is wound in two stages, upper and lower, and is connected to the left external electrode connection portion 24 via the left lead-out portion 23. The left external electrode connection portion 24 is bent in the width direction DW at a bending portion 48 at the tip of the left lead-out portion 23 and extends linearly in the width direction DW. The right end of the winding portion 22 is drawn out from the upper stage of the winding portion 22, which is wound in two stages, upper and lower, and is connected to the right external electrode connection portion 24 via the right lead-out portion 23. The right external electrode connection portion 24 is bent in the width direction DW at a bending portion 48 at the tip of the right lead-out portion 23 and extends linearly in the width direction DW. In other words, the left and right lead-out portions 23 each extend in an extension direction dc that inclines toward one side in the width direction DW as it extends outward in the length direction DL. The left and right external electrode connection portions 24 each extend in an extension direction dp extending from the other side in the width direction DW to the one side in the width direction DW. In Fig. 5, the portion of the lead-out portion 23 that slopes toward the one side in the width direction DW as it extends outward in the length direction DL is linear, but at least a portion of the portion may be curved. In Fig. 5, the portion of the external electrode connection portion 24 that extends from the other side in the width direction DW to the one side in the width direction DW is linear, but at least a portion of the portion may be curved.

[0039] As shown in Fig. 6, the conducting wire 42 constituting the coil conductor 20 has a conductor 43 which is a wire material and a coating layer covering the conductor 43 (the coating layer is not shown in Figs. 6 and 7). The coil conductor 20 is formed by alpha-winding the conducting wire 42. The coil conductor 20 is embedded in a core 30 containing magnetic particles and resin.

[0040] [A-1. Conductor] Fig. 7 is a cross-sectional view of the conductor 43 that constitutes the conducting wire 42. Fig. 7 shows a cross section perpendicular to the direction in which the conductor 43 extends. The conductor 43 has a rectangular shape with four right-angled corners in a conductor cross section perpendicular to the extension direction. Here, in this specification, "right angle," "rectangle," and "same" do not necessarily mean "right angle," "rectangle," or "same" in the strict sense, but may mean substantially "right angle," "rectangle," or "same." In other words, in this specification, "right angle," "rectangle," and "same" may also mean "approximately right angle," "approximately rectangular," or "approximately the same" if they are substantially "right angle," "rectangle," or "same," respectively.

[0041] Conductor 43 has conductor inner circumferential surface 43a on the winding axis K side, conductor outer circumferential surface 43b on the side away from winding axis K, and a pair of conductor side surfaces 43c, 43d connecting both ends of conductor inner circumferential surface 43a and both ends of conductor outer circumferential surface 43b, respectively. A coating layer is formed on the surface of conductor 43 to form conductor wire 42.

[0042] The maximum length between the conductor side surfaces 43c and 43d in the thickness direction DT of the conductor 43 is defined as the line width La. The maximum length between the conductor inner surface 43a and the conductor outer surface 43b in the direction perpendicular to the thickness direction DT of the conductor 43 is defined as the line thickness Lb.

[0043] Specifically, the angle formed between the conductor inner peripheral surface 43a and the conductor side surface 43c is a right angle. The angle formed between the conductor inner peripheral surface 43a and the conductor side surface 43d is also a right angle. The angle formed between the conductor outer peripheral surface 43b and the conductor side surface 43c is also a right angle. The angle formed between the conductor outer peripheral surface 43b and the conductor side surface 43d is also a right angle. In this embodiment, a right angle is determined when a corner is rounded with a curvature radius R of 4.5 μm or less at the intersection of the conductor inner peripheral surface 43a or the conductor outer peripheral surface 43b and the conductor side surface 43c, 43d, which respectively form a right angle. A method for confirming that the four corners of this conductor are right angles can be performed by observing the four corners of the conductor cross section with a digital microscope and measuring the curvature radius of each corner using the measurement function of the digital microscope.

[0044] Here, a virtual circumscribing rectangle S1 is set so as to circumscribe the conductor 43 in the conductor cross section. The circumscribing rectangle S1 is set so that the area ratio of the area occupied by the conductor 43 to the area of ​​the circumscribing rectangle S1 is maximized. If the conductor is left as is, this conductor cross section is a cross section cut perpendicular to the longitudinal direction DL of the conductor 42. The circumscribing rectangle S1 is set by observing the boundary line between the coating layer and the conductor 41 in this cross section. That is, the circumscribing rectangle S1 is set so that the line width La between the conductor side surfaces 43c and 43d in the thickness direction DT of the conductor 43 and the line thickness Lb between the conductor inner surface 43a and the conductor outer surface 43b in the direction perpendicular to the thickness direction DT of the conductor 43 are included in the circumscribing rectangle S1 in this cross section. Furthermore, when determining the inductor 1 of the product, the circumscribing rectangle S1 is set by observing the conductor cross section per turn of the winding portion 22 at a cut surface (cut surface shown in FIG. 6 ) taken perpendicularly along an imaginary line extending in the width direction DW of the element body 2 passing through the winding axis K of the winding portion 22 when viewed from above the element body 2. In this embodiment, the average area ratio of the conductor 43 to the circumscribing rectangle S1 per turn of the winding portion 22 is 95% or more. "Per turn" refers to the average value per turn, and refers to the average value of the area ratios of the conductor cross sections at two locations per turn in the element body cross section. Therefore, for example, in FIG. 6 , the average value of the area ratios at winding positions P1 and P2 may be taken. Also, for example, in FIG. 6 , the average value of the area ratios at winding positions P3 and P4 may be taken.

[0045] 7, a typical conductor 81 is formed by compressing a circular conductor, so that the inner circumferential surface 81a and the outer circumferential surface 81b are flat, while the conductor side surfaces 81c and 81d are curved and have a large curvature. Therefore, the area ratio of the typical conductor 81 to the circumscribed rectangle S1 tends to be small. In contrast, the conductor 43 of this embodiment is formed by casting, and is intentionally formed to have a rectangular shape with four right-angled corners. Therefore, compared to the typical conductor 81, the curvature of the curved shape of the conductor side surfaces 43c and 43d is smaller and more linear, resulting in a rectangular shape that more closely resembles the circumscribed rectangle S1.

[0046] As shown in Figure 6, in this embodiment, in the thickness direction DT, the coil conductor 20 is embedded inside the core 30 so that the top surface thickness T11, which is the length from the top surface 12 of the element body 2 to the top surface 41a of the winding portion 22, and the bottom surface thickness T12, which is the length from the bottom surface 41b of the winding portion 22 to the bottom surface 10 of the element body 2, are the same thickness.

[0047] In this embodiment, because the conductor 43 has a rectangular shape, when compared at the same DC resistance value (i.e., the area of ​​the conductor cross section is the same), the line width La can be made smaller than that of a normal conductor 81 by the area of ​​the corners of the conductor 43. Therefore, since the DC resistance value can be secured while reducing the height (thickness) in the thickness direction DT of the coil conductor 20, when the size of the element body 2 is approximately the same, it is easy to increase the top surface thickness T11 and the bottom surface thickness T12, and the sum T11+T12 of the top surface thickness T11 and the bottom surface thickness T12 can be increased.

[0048] In this embodiment, in the thickness direction DT, which is the direction along the winding axis K, the winding portion thickness T10, which is the length from the top surface 41a to the bottom surface 41b of the winding portion 22, is the same as the sum T11+T12 of the top surface thickness T11 and the bottom surface thickness T12. Alternatively, the winding portion thickness T10 may be equal to or less than the sum T11+T12. Specifically, the ratio of the winding portion thickness T10 to the height of the element body 2 is 55% or less.

[0049] This makes it easy to increase the sum T11+T12 of the top surface thickness T11 and the bottom surface thickness T12 relative to the winding portion thickness T10, so that even if the position of winding portion 22 is shifted in the vertical direction during manufacturing, the distance between winding portion 22 and the top and bottom surfaces of element body 2 can be maintained, thereby suppressing variations in the DC bias rated current of inductor 1. Here, the DC bias rated current specifies the lower limit current value at which this inductance can be used relative to the initial characteristics when no current is superimposed, as magnetic saturation occurs in the magnetic material when a current flows through the inductor, reducing the inductance.

[0050] In this embodiment, the coil conductor 20 is embedded inside the core 30 so that the top surface thickness T11 and the bottom surface thickness T12 are the same. However, the coil conductor 20 may be embedded inside the core 30 so that the top surface thickness T11 is larger than the bottom surface thickness T12. The coil conductor 20 may also be embedded inside the core 30 so that the bottom surface thickness T12 is larger than the top surface thickness T11. When either the top surface thickness T11 or the bottom surface thickness T12 is larger, the smaller thickness is formed so that it is not smaller than 1 / 6 of the sum of the top surface thickness T11 and the bottom surface thickness T12 (T11 + T12).

[0051] [A-2. Coil conductor] [A-2-1. Winding section configuration] As described above, the size of inductor 1 is very small, with a length L of 1.4 mm, a width W of 1.2 mm, and a thickness T of 0.8 mm. For this reason, the shape of winding portion 22 embedded in core 30 of element body 2 can have a significant effect on the inductance value that can be achieved in inductor 1.

[0052] 8A and 8B are diagrams illustrating the configuration of a winding portion 85 of a coil conductor 84 in an inductor 83 in which the winding portion of the coil conductor is wound in a normal winding manner. Figures 8A and 8B are diagrams showing two winding regions 85a and 85b constituting the winding portion 85 of an inductor 83 having a configuration similar to that of FIG. 1 in which the winding portion of the coil conductor is wound in a normal winding manner, as viewed from a direction corresponding to the -DT direction (a direction looking down on the top surface 12) in FIG. 1. Also, FIG. 8C is a diagram showing a cross section of the inductor 83 corresponding to the LT cross section taken along the center of the width W in FIG. 1, as viewed from a direction corresponding to the DW direction in FIG. 1.

[0053] A coil conductor 84 including a winding portion 85 consisting of winding regions 85a and 85b, a lead-out portion drawn out from the winding portion 85, and an external electrode connection portion 88 that is a conductor portion connected to the lead-out portion for connecting to an external electrode, together with a core 86 containing magnetic particles and having the coil conductor 84 embedded therein, constitutes an element body 87. In Fig. 8(a), the conductor of winding region 85a that constitutes winding portion 85 winds around the winding axis and is drawn out from the outermost periphery of winding region 85a to the right side in the illustration via the lead-out portion and connected to external electrode connection portion 88 on the right side in the illustration, and in Fig. 8(b), the conductor of winding region 85b winds around the winding axis and is drawn out from the outermost periphery of winding region 85b to the left side in the illustration via the lead-out portion and connected to external electrode connection portion 88 on the left side in the illustration. 8(a) and the conductor in the winding region 85b shown in FIG. 8(b) are connected to each other at a position P80 on the inner periphery of the winding portion 85. In FIG.

[0054] The total number of turns of winding unit 85 is an odd integer, for example 5, rounded up to the nearest integer, and winding regions 85a and 85b, which overlap along the winding axis to form winding unit 85, are each made up of the same number of turns, approximately 2.5. Therefore, in a cross section along the direction of winding axis Kp (the direction normal to the paper surface in Figures 8(a) and 8(b)) of the portion where the conductor wire winds as seen from the top surface of element body 87, the two winding regions 85a and 85b have two ranges R81 and R82 where the numbers of cross sections of the conductor wire included in one winding region 85a and the other winding region 85b are different from each other in the portion adjacent to each other along the direction of winding axis Kp.

[0055] FIG. 8(c) is a cross-sectional view of element body 87 taken along centerline CL80 in the width direction of element body 87 in FIGS. 8(a) and 8(b), including cross sections of ranges R81 and R82. As shown in FIG. 8(c), in inductor 83, in which the winding portion of the coil conductor is wound in a conventional manner, winding regions 85a and 85b have their inner peripheries at the same positions P82 and P83. The inner two turns of winding regions 85a and 85b are stacked vertically and at the same position, while the outermost 0.5 turns are located at the left and right outer peripheries, respectively. Therefore, a step S80 is formed between winding regions 85a and 85b on the left and right sides of the illustration on the outer periphery of winding portion 85. The depth of step S80 may be equivalent to the thickness T80 of the conductor measured in a direction perpendicular to winding axis Kp.

[0056] In the core 86 that constitutes the element body 87, the portion of the step S80 is dead space, and can limit the upper limit of the inductance that can be realized as the inductor 83.

[0057] For this reason, in the inductor 1 of this embodiment, in the portion corresponding to ranges R81 and R82 shown in Figure 8, the inner circumference of one winding region having a smaller number of cross sections of the conductor wire is shifted toward the outer periphery relative to the inner circumference of the other winding region having a larger number of cross sections of the conductor wire.

[0058] 9 is a diagram illustrating the configuration of the winding portion 22 of the coil conductor 20 in one embodiment of the inductor 1, and corresponds to FIG. 8 showing the configuration of an inductor 83 in which the winding portion of the coil conductor described above is wound in a normal winding manner. As described above with reference to FIG. 3, the coil conductor 20 includes the winding portion 22 in which a conductor wire is wound around the winding axis K, a pair of lead-out portions 23 led out from the winding portion 22, and a pair of external electrode connecting portions 24 which are conductor wire portions connected to the lead-out portions 23, respectively, for connecting to external electrodes. The winding portion 22 also includes two winding regions 22a and 22b that overlap along the winding axis K.

[0059] The conducting wire that constitutes the coil conductor 20 has a conductor and a coating layer that covers the surface of the conductor. The conductor has a rectangular cross section perpendicular to the direction in which the conductor extends, and the four vertices of the rectangle are right angles.

[0060] 9(a) and 9(b) are views of two winding regions 22a and 22b constituting winding portion 22, respectively, as viewed from the -DT direction (looking down on top surface 12) in FIG. 1. Also, FIG. 9(c) is a view of a cross section of inductor 1 corresponding to the LT cross section along center line CL20 of width W (see FIG. 1) of element body 2, as viewed from the DW direction.

[0061] 9(a), the conductor wires of winding region 22a are drawn out to the right side of the figure and connected to external electrode connection portion 24 on the right side of the figure via lead-out portion 23, and in Fig. 9(b), the conductor wires of winding region 22b are drawn out to the left side of the figure and connected to external electrode connection portion 24 on the left side of the figure via lead-out portion 23. Furthermore, the conductor wires of winding region 22a shown in Fig. 9(a) and the conductor wires of winding region 22b shown in Fig. 9(b) are connected to each other at position P20 on the inner periphery of winding portion 22.

[0062] 9, the total number of turns of the winding portion 22 is an odd integer, for example, 5, rounded to the nearest whole number. However, this total number of turns is an example to illustrate the difference from inductor 83, in which the winding portion of the coil conductor shown in FIG. 8 is wound in a normal winding manner, and the total number of turns of the winding portion 22 can be set to any odd number depending on the inductance value required for the inductor 1.

[0063] Winding regions 22a and 22b constituting winding unit 22 are each configured with the same number of windings, approximately 2.5 times. Therefore, in a cross section along the direction of winding axis K (the direction normal to the paper surface in Figures 9(a) and 9(b)) of the portion where the conductor wire is wound as seen from top surface 12 of element body 2, the two winding regions 22a and 22b have two ranges R20 and R21 where the numbers of cross sections of the conductor wire included in the two winding regions 22a and 22b adjacent along the direction of winding axis K are different between one winding region 22a and the other winding region 22b.

[0064] In inductor 1, winding portion 22 has a substantially rectangular shape in plan view when viewed from the direction of winding axis K, and ranges R20 and R21 are on two opposing sides of the substantially rectangular shape.

[0065] FIG. 9(c) is a diagram showing a cross section of element body 2 taken along center line CL20 in the width direction of element body 2 in FIGS. 9(a) and 9(b), and includes cross sections of ranges R20 and R21.

[0066] 9(c), one winding region 22a includes fewer conductors than the other winding region 22b in one range R20, and includes more conductors than the other winding region 22b in the other range R21. Similarly, one winding region 22b includes fewer conductors than the other winding region 22a in one range R21, and includes more conductors than the other winding region 22a in the other range R20.

[0067] In this embodiment, the ranges R20 and R21 are arranged on two opposing sides of the winding section 22 that are parallel to the end face 14 of the element body 2, as shown in Figures 9(a) and (b), so as not to be located near position P20 on the inner circumference of the winding section 22 that connects the winding region 22a and the winding region 22b to each other. In particular, as shown in Figure 9(c), in the ranges R20 and R21, the inner circumference of one winding region that has a smaller number of cross sections of the conductor wire in a cross section along the direction of the winding axis K is shifted toward the outer periphery of the winding section 22 relative to the inner circumference of the other winding region that has a larger number of cross sections of the conductor wire in a cross section along the direction of the winding axis K.

[0068] Specifically, in range R20, the inner periphery of winding region 22b, which has a smaller number of conductor cross sections in a cross section taken along the direction of winding axis K, is shifted by a distance D21 toward the outer periphery of winding unit 22 relative to the inner periphery of winding region 22a, which has a larger number of conductor cross sections in a cross section taken along the direction of winding axis K. Also, in range R21, the inner periphery of winding region 22a, which has a smaller number of conductor cross sections in a cross section taken along the direction of winding axis K, is shifted by a distance D20 toward the outer periphery of winding unit 22 relative to the inner periphery of winding region 22b, which has a larger number of conductor cross sections in a cross section taken along the direction of winding axis K.

[0069] In the example of Figure 9(c), distances D20 and D21 are both the same as thickness T20 of the conductor measured in a direction perpendicular to winding axis K. This prevents a step from occurring between the outer periphery of winding region 22a and the outer periphery of winding region 22b in each of ranges R20 and R21. That is, in each of ranges R20 and R21, the outer peripheries of two winding regions 22a and 22b are formed so that the difference in distance from winding axis K between one winding region and the other winding region is within half the thickness of the conductor, and in Figure 9(c), the distances from winding axis K are approximately the same.

[0070] With the above configuration, winding portion 22 of inductor 1 does not have a step S80 on the outer periphery of winding portion 85, which is formed in inductor 83 in which the winding portion of the coil conductor is wound in a normal winding manner as shown in Fig. 8(c). In other words, inductor 1 does not have step S80 as shown in Fig. 8(c), and therefore the upper limit of inductance that can be achieved by inductor 1 can be improved compared to inductor 83 in which the winding portion of the coil conductor is wound in a normal winding manner. Furthermore, in inductor 1 shown in Fig. 9, winding axes with high magnetic flux density can be formed large in each of winding regions 22a and 22b.

[0071] It is not necessary for the inner periphery of one of the two winding regions 22a, 22b to be offset from the inner periphery of the other winding region throughout the entire winding direction (circumferential direction about winding axis K) of each of the ranges R20 and R21. That is, it is sufficient for the inner periphery of one of the two winding regions 22a, 22b, which has a smaller number of conductor cross sections in a cross section taken along winding axis K, to be offset toward the outer periphery of winding unit 22 relative to the inner periphery of the other winding region, which has a larger number of conductor cross sections in a cross section taken along winding axis K, over at least a portion of the winding direction of each of the ranges R20 and R21.

[0072] 9(c) 。 Also, the amount of deviation of the inner circumference of one winding region from the inner circumference of the other winding region in ranges R20 and R21, i.e., distances D20 and D21 in FIG. 9(c) , may be at least half the thickness T20 of the conductor measured in a direction perpendicular to winding axis K. In this case, too, the size of the step between winding regions 22a and 22b at the outer periphery of winding portion 22 is made smaller than step S80 in inductor 83 in which the winding portion of the coil conductor is wound in a normal winding manner, as shown in FIG. 8(c), thereby making it possible to improve the upper limit of the inductance that can be achieved by inductor 1 compared to inductor 83 in which the winding portion of the coil conductor is wound in a normal winding manner.

[0073] [A-2-2. Configuration of lead-out section and external electrode connection section] As described above in the background art, in an inductor having an element body including a core containing magnetic particles formed of a soft magnetic material and a coil conductor embedded in the core, such as the inductor 1 shown in Fig. 1, variations can occur in the position and exposed area of ​​the lead-out portions on the end faces of the element body due to the overall shape of the coil conductor and the orientation of the coil conductor inside the element body, etc. Such variations in the position and exposed area of ​​the lead-out portions on the end faces of the element body can cause variations in the electrical connection state between the lead-out portions and external electrodes, and can cause variations in the DC resistance value at the connection between the lead-out portions and external electrodes.

[0074] For this reason, in the inductor 1 of this embodiment, the shape of the coil conductor 20, in particular the angle formed between the lead-out portion 23 led out from the winding portion 22 and the external electrode connection portion 24, is configured to satisfy predetermined conditions in a plan view seen from the normal direction to the top surface 12 of the element body 2. Furthermore, in the inductor 1, the orientation of the coil conductor 20 inside the element body 2, in particular the angle formed between the normal direction to the end surface 14 of the element body 2 on which the external electrode 4 is formed and the extension direction of the external electrode connection portion 24, is configured to satisfy predetermined conditions in a plan view seen from the normal direction to the top surface 12 of the element body 2.

[0075] 10 is a view of the coil conductor 20 embedded in the element body 2 in one embodiment of the inductor 1, viewed from above the top surface 12 of the element body 2 in the -DT direction. In the inductor 1 shown in Fig. 10, as shown particularly in the left portion of the inductor 1, the boundary between the lead-out portion 23 and the external electrode connection portion 24 is a bent portion 48 where the conductor is bent, and a first angle θ1 formed by an extension direction dp of the external electrode connection portion 24 extending from the bent portion 48 as a starting point and a normal direction dn of the end face 14 that passes through the bent portion 48 and points toward the inside of the element body 2 is greater than 90 degrees. When this first angle θ1 is smaller than 90 degrees, the entire external electrode connection portion 24, from its base to its tip, moves away from the end face 14 of the element body 2 toward the inside of the element body, and the exposed area of ​​the external electrode connection portion 24 exposed at the end face 14 becomes smaller. Furthermore, if the first angle θ1 is 90 degrees, the exposed area of ​​the external electrode connecting portion 24 exposed from the end face 14 can be increased, but if the bent portion 48 is misaligned toward the inside of the element body 2, there is a possibility that the external electrode connecting portion 24 will be buried in the element body 2. In contrast, if the first angle θ1 is greater than 90 degrees, the tip side of the external electrode connecting portion 24 will extend in a direction protruding from the end face 14 of the element body 2, and the tip of the external electrode connecting portion 24 will contact the inner wall of the molding die in the element body molding and curing step described above, thereby extending nearly parallel to the end face 14 of the element body 2, thereby increasing the exposed area of ​​the external electrode connecting portion 24 exposed from the end face 14. The lead-out portion 23 and external electrode connecting portion 24 on the right side of the inductor 1 in the figure may also be configured in a similar manner to the above, and the first angle θ1 may be defined accordingly.

[0076] This reduces the variation in the exposed area of ​​the external electrode connecting portion 24 exposed from the end face 14 of the inductor 1, thereby reducing the variation in DC resistance at the connection between the external electrode connecting portion 24 and the external electrode 4. Here, when the first angle θ1 is greater than 90 degrees on both the left and right end faces 14 of the inductor 1 in the drawing, it is possible to reduce the variation in the exposed area of ​​the external electrode connecting portion 24 exposed from each end face 14 on each of the left and right end faces 14 in the drawing, thereby reducing the variation in DC resistance at the connection between the external electrode connecting portion 24 and the external electrode 4.

[0077] 10, the second angle θ2 formed between the extension direction dc of the lead-out portion 23 starting from the bent portion 48 and the extension direction dp of the external electrode connection portion 24 extending from the bent portion 48 is equal to or greater than 150 degrees and less than 180 degrees. This makes it possible to further reduce the variation in the exposed area of ​​the external electrode connection portion 24 exposed from the end face 14.

[0078] From the viewpoint of reducing variations in the exposed area of ​​the external electrode connecting portion 24, the first angle θ1 is preferably greater than 90 degrees as described above, and is also preferably in the range of 100 degrees or less.

[0079] 10, the coil conductor 20 is embedded in the element body 2 so that the winding axis K is aligned along the normal direction to the top surface 12 (normal direction to the page). In addition, in a plan view seen from the normal direction to the top surface 12 (i.e., the plan view shown in FIG. 10), the outline of the winding portion 22 is such that a first length Wc, which is the maximum length in a direction perpendicular to the side surface 16 (e.g., the DW direction), is equal to or greater than a second length Lc, which is the maximum length measured in a direction perpendicular to the end surface 14 (e.g., the DL direction). The ratio of the first length Wc to the second length Lc may be in the range of 1 to 1.5.

[0080] The relationship between the winding portion 22 and the element body 2 is such that the first length Wc of the winding portion 22 is longer than the second length Lc, and the distance Ld between a pair of end faces 14 of the element body 2 is longer than the distance Wb between a pair of side faces 16. Here, the distance Ld is equal to the length L of the inductor 1 minus the thickness of the external electrode 4, and the distance Wb is approximately equal to the width W of the inductor 1.

[0081] From the viewpoint of reducing the variation in the exposed area of ​​the external electrode connection portion 24, it is further preferable that the width of the bent portion 48 in a direction perpendicular to the pair of side surfaces 16 (e.g., the DW direction) is within a range R25 that is 1 / 2 of the distance Wb between the pair of side surfaces 16, centered on a line L25 that passes through the center of the end face 14 and is parallel to the side surfaces 16.

[0082] The length of the external electrode connection portion 24 is preferably 30% to 50% of the distance Wb between the pair of side surfaces 16 of the end face 14 .

[0083] For example, the element body 2 has a distance Wb between a pair of side surfaces 16 of 1.2 mm or more and 1.4 mm or less, and a distance Ld between a pair of end surfaces 14 of 1.4 mm or more and 1.6 mm or less. Here, the actual size of the inductor 1 may include an error of about a few percent compared to the nominal size of the inductor 1 described above, which is a length L of 1.4 mm, a width W of 1.2 mm, and a thickness T of 0.8 mm. It should be noted that the above size of the inductor 1 refers to the overall size of the inductor 1 including the external electrodes 4, and that the size of the element body 2 is generally smaller than the size of the inductor 1, and the ratio of the distance Wb between the side surfaces 16 to the distance Ld between the end surfaces 14 may also differ from the ratio of the width W to the length L of the overall external shape of the inductor 1.

[0084] [B. External electrode] Next, the connection configuration between the external electrodes and the external electrode connecting portions 24 of the coil conductor 20, and the configuration of the external electrodes on the surface of the element body will be described. [B-1. Connection configuration between external electrodes and external electrode connection parts] Fig. 11 is a cross-sectional view taken along line XI-XI in Fig. 5. Fig. 11 shows a cross section perpendicular to the extending direction dp of the external electrode connecting portion 24 at the connection portion between the external electrode connecting portion 24 and the external electrode 4. A pair of external electrodes 4 are provided on the surface of the element body 2. The external electrodes 4 are connected to the conductor 43 that is exposed when the coating layer 45 of the external electrode connection portion 24 is removed. The external electrodes 4 have a plated conductor 50 formed by plating. The plated conductor 50 of this embodiment has a copper plating layer 51 as a plating layer of the same metal component as the conductor 43. The copper plating layer 51 is a plating layer that plates the surface of the conductor 43. The copper plating layer 51 and the conductor 43 are connected.

[0085] A Ni plating layer 52 is formed on the copper plating layer 51. A Sn plating layer 53 is formed on the Ni plating layer 52. The plated conductor 50 of this embodiment has the copper plating layer 51, the Ni plating layer 52, and the Sn plating layer 53. The plated conductor 50 is formed on the conductor outer peripheral surface 43b of the external electrode connection portion 24 and on conductor side surfaces 43c and 43d that are exposed after the coating layer 45 of the conductive wire 42 of the external electrode connection portion 24 has been removed. As shown in FIG. 11 , the exposed amounts of the conductor side surfaces 43c and 43d are different. That is, in FIG. 11 , the positions of the ends of the coating layer 45 on the external electrode 4 side of the conductor side surface 43c and the conductor side surface 43d are different in the left-right direction, and the exposed amount of the conductor side surface 43d is greater than that of the conductor side surface 43c.

[0086] FIG. 12 is a cross-sectional view of the case where a normal conductor 81 corresponding to FIG. 11 is used. In a normal conductor 81, the four corners are not rectangular, so the length of the conductor outer surface 81b in the direction of the line width La is shorter than the line width La of the conductor 81, and the conductor side surfaces 81c and 81d on both sides of the conductor outer surface 81b in the direction of the line width La tend to be curved surfaces with a large curvature. Here, when manufacturing an inductor, with a conductive wire 80 of a normal conductor 81, when the coil conductor 20 is embedded in the element body 2, the thickness of the element body 2 on the curved surface where the conductor outer peripheral surface 81b is connected to the conductor side surfaces 81c, 81d (in other words, the length in the longitudinal direction DL from the outer surface of the element body 2 to the curved surface) becomes larger than the thickness of the element body 2 on the conductor outer peripheral surface 81b (in other words, the length in the longitudinal direction DL from the outer surface of the element body 2 to the conductor outer peripheral surface 81b). For this reason, when the coating layer 45 on the conductor outer peripheral surface 81b side of the conductive wire 80 embedded in the element body 2 is peeled off in the surface treatment step, only the coating layer 45 on the conductor outer peripheral surface 81b side is likely to peel off due to the difference in thickness of the element body 2, and the coating layer 45 and magnetic particles on the curved surfaces where the conductor outer peripheral surface 81b is connected to the conductor side surfaces 81c, 81d tend to remain. For this reason, when plating is grown on the conductor outer peripheral surface 81b, a constricted shape 81e is likely to be formed at the connection portion between the conducting wire 80 and the plated conductor 50. That is, in a normal conductor 81, the conductor outer peripheral surface 81b and the plated conductor 50 are connected in such a way that this constricted shape 81e is formed, and therefore the connection area between the conductor 81 and the plated conductor 50 is likely to be narrower than the line width La. This has led to problems such as an increase in the DC resistance of the external electrode 4 and a decrease in the connection reliability between the external electrode 4 and the conductor 81 of the coil conductor 20.

[0087] In contrast, because the conductor 43 in this embodiment has a substantially rectangular shape, when the coil conductor 20 is embedded in the element body 2, the thickness of the element body 2 on the corners between the conductor outer peripheral surface 43b and the conductor side surfaces 43c, 43d is unlikely to become larger than the thickness of the element body 2 on the conductor outer peripheral surface 43b. Therefore, when the coating layer 45 on the conductor outer peripheral surface 43b side of the conducting wire 42 embedded in the element body 2 is peeled off in the surface treatment step, not only the coating layer 45 on the conductor outer peripheral surface 43b but also the coating layer 45 on the conductor side surfaces 43c, 43d on the conductor outer peripheral surface 43b side can be peeled off.

[0088] 11, the positions of the ends of coating layer 45 on conductor side surface 43c and conductor side surface 43d are different in the left-right direction due to the direction of laser irradiation in the surface treatment process. That is, in FIG. 11, the resin layer is removed with the laser light while moving the laser light from bottom to top (in the direction from conductor side surface 43d toward conductor side surface 43c relative to conductor wire 42). Therefore, on conductor side surface 43d, the laser light moves toward the resin layer 45, making it easier to remove the coating layer 45, whereas on conductor side surface 43c, the laser light moves away from the resin layer 45, making it more difficult to remove the coating layer 45. Therefore, the position of the end of coating layer 45 on conductor side surface 43d is removed further inside element body 2 than the position of the end of the coating layer on conductor side surface 43c.

[0089] In this case, when plating is grown on the conductor outer peripheral surface 43b, plating is likely to be formed not only on the conductor outer peripheral surface 43b but also at positions adjacent to the conductor outer peripheral surface 43b on the conductor side surfaces 43c and 43d exposed from the coating layer 45, resulting in the formation of plated conductors 50 that protrude outward in the thickness direction DT from the conductor side surfaces 43c and 43d. This allows the shape formed by the conductor outer peripheral surface side of the conductor 43 and the plated conductor 50 to expand toward the outer surface of the element body 2, preventing the formation of a constricted shape in the conductor side surfaces 43c and 43d, and allowing the connection area between the conductor outer peripheral surface 43b and the plated conductor 50 to be similar in size to the line width La. Specifically, of the angles θ3 and θ4 formed by the circumscribing line 50a of the plated conductor 50 formed on the conductor outer peripheral surface 43b and the circumscribing line 50b of the plated conductor 50 formed on the conductor side surfaces 43c and 43d, the plated conductors 50 are formed on the conductor side surfaces 43c and 43d such that the angle θ3 on the conductor 43 side is 90 degrees or less.

[0090] This can also be expressed as follows. That is, in the cross section shown in FIG. 11 , a virtual inscribed rectangle S2 is set so as to inscribe in the surface of the copper plating layer 51 formed on the conductor inner circumferential surface 43a, conductor side surfaces 43c and 43d, and conductor outer circumferential surface 43b of the conductor 43. This inscribed rectangle S2 is a virtual rectangle set on the conductor 43 side so as to satisfy the following four conditions. First, the side S2b of the inscribed rectangle S2 on the conductor outer circumferential surface 43b side is set so as to inscribe in the copper plating layer 51 of the plated conductor 50. Second, the inscribed rectangle S2 is set so that the side S2a on the conductor inner circumferential surface 43a side (the side S2a opposite to side S2b) is inscribed in the conductor 43 (including the case where the side S2a is inscribed at the end of side S2a, i.e., the corner). Third, the inscribed rectangle S2 is set so that the area ratio of the area occupied by the conductor 43 and the copper plating layer 51 to the area of ​​the inscribed rectangle S2 is maximized while satisfying the first and second conditions.

[0091] In this embodiment, within the inscribed rectangle S2 set in this manner, corners S2e and S2f on the conductor inner peripheral surface 43a side are likely to be occupied by the right-angled rectangular conductor 43, and corners S2g and S2h on the copper plating layer 51 side are occupied by the copper plating layer 51 on the conductor outer peripheral surface 43b. In this case, the area ratio of the conductor 43 and the copper plating layer 51 to the inscribed rectangle S2, i.e., the area ratio of copper, the metal of the conductor 43, was 99% or more.

[0092] Therefore, in the conductor 43 of this embodiment, the conductor cross section has a rectangular shape with four right-angled corners, which makes it easy to connect to the coil conductor 20 with the copper plating layer 51 that is equal to or larger than the conductor outer peripheral surface 43b, and provides a wide connection between the conductor 43 and the plated conductor 50. This makes it possible to reduce the DC resistance of the external electrode 4 and improve the connection reliability between the external electrode 4 and the coil conductor 20. As shown in FIG. 12, when an inscribed rectangle S2 is set for a normal conductor 81 as described above, a constricted shape 81e enters the inscribed rectangle S2.

[0093] [B-2. Configuration of external electrodes on the element surface] Next, the configuration of the external electrodes 4 on the surface of the element body will be described. [B-2-1. Configuration of planned electrode locations and external electrode connection parts] 13 is a side view of the inductor 1 viewed from the end face 14 side of the element body 2. As described above, the external electrode 4 is formed by plating to cover the intended electrode region R30. The intended electrode region R30 is formed by peeling off the element body coat 70, which is an insulating resin that has been applied to the surface of the element body in the element body protective layer formation process, in the surface treatment process. The intended electrode region R30 is formed in a rectangular shape on each of the end face 14 and the bottom face 10 of the element body 2.

[0094] 13 , the intended electrode location R30 is formed in a region overlapping the portion of the external electrode connection portion 24 exposed from the end face 14 of the element body 2. The external electrode connection portion 24 is exposed on the end face 14 of the element body 2 in the width direction DW of the element body 2, spanning the intended electrode location R30 and a coated location R31, which is a region outside the intended electrode location R30. Of the portion of the external electrode connection portion 24 exposed from the end face 14 of the element body 2, the coated portion 64b located at the coated location R31 is located closer to the tip 64c of the external electrode connection portion 24 than the peeled portion 64a located at the intended electrode location R30. In other words, the tip 64c of the external electrode connection portion 24 is located at the coated location R31. The area of ​​the peeled portion 64a is set to be larger than the cross-sectional area of ​​the conducting wire that constitutes the coil conductor 20.

[0095] As described above, the surface protection layer forming step is performed after the element body forming and hardening step and the element body grinding step. That is, after the surface protection layer forming step, the entire surface of the external electrode connection portion 24 exposed from the end face 14 is coated with an insulating resin. Furthermore, in the surface treatment step, part of this coating is peeled off to form the intended electrode portion R30.

[0096] At this time, in the external electrode connection portion 24 exposed from the end face 14 of the element body 2, only the coating applied to the peeled portion 64a is peeled off, and the peeled portion 64a is connected to the external electrode 4 in the plating layer formation step. As described above, the area of ​​the peeled portion 64a is set larger than the cross-sectional area of ​​the conducting wire that makes up the coil conductor 20, so that the resistance at the connection portion between the peeled portion 64a and the external electrode 4 is unlikely to become large.

[0097] On the other hand, even after the surface treatment step, the element coating 70 remains on the coating area R31. Therefore, the covered portion 64b is covered with the element coating 70, and at least the tip 64c of the external electrode connection portion 24 is covered with the element coating 70. With the covered portion 64b and the tip 64c covered with the element coating 70, the external electrode connection portion 24 exposed from the end face 14 is fixed to the end face 14 on the tip 64c side by the element coating 70. Therefore, the external electrode connection portion 24 is unlikely to peel off from the end face 14 until the external electrode 4 is formed, and the connection between the external electrode 4 and the external electrode connection portion 24 is likely to be stable.

[0098] 13, the coating location R31 has a first thickness region 70a and a second thickness region 70b. The coated portion 64b is covered by both the first thickness region 70a and the second thickness region 70b. Furthermore, in the external electrode connection portion 24 exposed from the end face 14 of the element body 2, in the peeled portion 64a, the coating layer of the conductor wire is removed when the coating is removed, and the exposed conductor is connected to the external electrode 4 in the plating layer formation step, and in the coated portion 64b, the coating layer of the conductor wire remains intact and is covered by the element body coat 70 (i.e., both the first thickness region 70a and the second thickness region 70b), with the coating layer of the conductor wire being between the conductor and the element body coat 70. Furthermore, the area of ​​the region of the external electrode connection portion 24 that is connected to the external electrode is equal to or greater than the cross-sectional area of ​​the conductor wire that constitutes the coil conductor 20.

[0099] [B-2-2. Composition of external electrodes and element coating] As shown in FIG. 13, when the inductor 1 is viewed from one end face 14 side, the external electrode 4 is positioned biased toward the bottom face 10 side of the end face 14, and the external electrode 4 is surrounded by the element coat 70. The first thickness region 70a is formed in the boundary region between the planned electrode region R30 and the coating region R31. The second thickness region 70b is located farther from the planned electrode region R30 than the first thickness region 70a when viewed from the planned electrode region R30. The first thickness region 70a is provided at a position where it surrounds the planned electrode region R30, which is formed on the end surface 14 and the bottom surface 10 of the element body 2, at the end surface 14 and the bottom surface 10.

[0100] Fig. 14 is a diagram schematically showing the XIV-XIV cross section of Fig. 13. The XIV-XIV cross section is a cross section perpendicular to the boundary between the planned electrode region R30 and the coating region R31 when viewed from the side of the end face 14 of the element body 2. In other words, the XIV-XIV cross section is a cross section obtained by cutting the element body 2 in the longitudinal direction DL along a straight line perpendicular to the boundary between the external electrode 4 and the element body coating 70 when viewed from the end face 14. In addition, in the XIV-XIV cross section, the DT direction is the direction away from the planned electrode region R30.

[0101] The first thickness region 70a is formed by removing a portion of the element coat 70 by irradiating the laser beam during the surface treatment process while adjusting the irradiation time and irradiation power so that the irradiation dose is smaller than the irradiation dose of the laser beam irradiated onto the predetermined electrode region R30. Therefore, the thickness of the first thickness region 70a is smaller than the average thickness T30 of the element coat 70.

[0102] The average thickness T30 is the average value of the thickness of the element coating 70 at positions sufficiently distant from the planned electrode location R30, within the element coating 70 that entirely covers the element body 2. The average thickness T30 is determined, for example, as the average value of the thicknesses of the element coating 70 measured at any three points in the center of the upper surface, centered on the winding axis K, on ​​a cross section obtained by cutting the element body 2 vertically along an imaginary line that extends in the longitudinal direction DL of the element body 2 and passes through the winding axis K of the coil, when viewed from above.

[0103] The second thickness region 70b is a portion of the element coat 70 formed in the surface protection layer forming step that was not exposed to laser light in the surface treatment step. The thickness of the second thickness region 70b is approximately equal to the average thickness T30 and is greater than the thickness of the first thickness region 70a.

[0104] As shown in FIG. 14 , in the XIV-XIV cross section, the first thickness region 70a is provided with a flat portion 75 and a step portion 71. The flat portion 75 is a portion of the first thickness region 70a where the thickness of the element coat 70 is generally constant on average. The step portion 71 is a portion of the first thickness region 70a where the thickness increases rapidly in a direction away from the planned electrode location R30. The step portion 71 connects the flat portion 75 and the second thickness region 70b, which have different thicknesses, and the formation of the step portion 71 makes it easier to form the flat portion 75 and the second thickness region 70b. The step portion 71 is formed at an angle of, for example, approximately 17 degrees relative to the flat portion 75.

[0105] As shown in FIG. 14 , a peripheral edge 65, which is a part of the external electrode 4, is formed on the first thickness region 70a. A tip 65a of the peripheral edge 65 of the external electrode 4, which is located farthest from the planned electrode location R30, is located on the flat portion 75 of the first thickness region 70a. Therefore, the peripheral edge 65 of the external electrode 4 is not formed on the step portion 71 or the second thickness region 70b. In other words, the tip 65a of the peripheral edge 65 of the external electrode 4 is located closer to the planned electrode location R30 than the step portion 71 and the second thickness region 70b. Furthermore, the length of the peripheral edge 65 of the external electrode 4 in the direction away from the planned electrode location R30 is shorter than the length of the flat portion 75 of the first thickness region 70a. In other words, in the XIV-XIV cross section, the length of the flat portion 75 in the direction away from the planned electrode location R30 is longer than the length of the portion (peripheral edge 65) of the external electrode 4 formed on the element coat 70. This makes it easier for the entire periphery 65 of the external electrode 4 to be formed on the flat portion 75 of the first thickness region 70a.

[0106] The external electrode 4 has a copper plating layer (first plating layer) 51, a Ni plating layer (second plating layer) 52, and a Sn plating layer (third plating layer) 53. The copper plating layer 51 is the first portion to be plated in the plating layer formation step. A small amount of the copper plating layer 51 is also formed on the coating area R31. However, because the element body coat 70 is insulating, the thickness of the copper plating layer 51 of the external electrode 4 on the coating area R31, i.e., the copper plating layer 51 on the periphery 65 of the external electrode 4, is smaller than the thickness of the copper plating layer 51 formed in contact with the core 30 constituting the element body 2 at the intended electrode area R30.

[0107] The Ni plating layer 52 is formed by plating after the copper plating layer 51 and is a layer formed on the copper plating layer 51. The Sn plating layer 53 is formed by plating after the Ni plating layer 52 and is a layer formed on the Ni plating layer 52. The Ni plating layer 52 and the Sn plating layer 53 on the periphery 65 of the external electrode 4 are formed on the copper plating layer 51 and the Ni plating layer 52, which are conductors, respectively. Therefore, the thicknesses of the Ni plating layer 52 and the Sn plating layer 53 on the periphery 65 of the external electrode 4 are approximately equal to the thicknesses of the Ni plating layer 52 and the Sn plating layer 53 located in the intended electrode region R30.

[0108] Since the copper plating layer 51 on the periphery 65 of the external electrode 4 is thinner than the copper plating layer 51 in other parts, the periphery 65 is formed to have a thickness smaller than the average thickness T33 of the external electrode 4.

[0109] The average thickness T33 of the external electrode 4 is greater than the average thickness T30, and the external electrode 4 protrudes outward from the end face 14 and the bottom face 10 more than the element body coating 70. In other words, in the XIV-XIV cross section, the thickness of the portion of the external electrode 4 formed on the surface of the element body 2 (the portion formed in the intended electrode portion R30) is greater than the thickness of the second thick region 70b. This makes it easier to connect the external electrode 4 to a substrate or the like when mounted. The average thickness T33 of the external electrode 4 is determined, for example, as the average thickness at any three or more points on the external electrode 4, excluding the periphery 65 and the portion connected to the peeled portion 64a, on a cross section taken along a virtual line extending perpendicularly in the longitudinal direction DL of the element body 2 and passing through the winding axis K of the coil when viewed from above.

[0110] As described above, the peripheral edge 65 of the external electrode 4, which is thinner than the average thickness T33, is formed on the first thickness region 70a, which has a thickness equal to or less than the thickness of the second thickness region 70b. Therefore, the peripheral edge 65 of the external electrode 4 on the first thickness region 70a is less likely to protrude in a direction away from the element body 2. That is, the peripheral edge 65 of the external electrode 4 is less likely to protrude outside the end face 14 and bottom face 10 of the element body 2 than the external electrode 4 formed in the intended electrode location R30. Furthermore, the thickness of the tip 65a of the external electrode 4 is smaller than the difference in thickness between the first thickness region 70a and the second thickness region 70b, and the tip 65a of the external electrode 4 is located closer to the element body 2 and core 30 than the surface of the second thickness region 70b. Therefore, the tip 65a is less likely to protrude in a direction away from the element body 2.

[0111] Furthermore, as described above, the first thickness region 70a is disposed at a position surrounding the intended electrode location R30, and therefore the first thickness region 70a surrounds the external electrode 4. Therefore, around the external electrode 4, the peripheral edge 65 is less likely to protrude in a direction away from the element body 2 and the core 30.

[0112] Fig. 15 is a cross-sectional view taken along line XIV-XIV in Fig. 13. As shown in Fig. 15, the thickness and shape of the first thickness region 70a actually vary depending on the accuracy of the laser processing performed to irradiate the element coat 70 with laser light. Below, specific definitions of each element will be described with reference to Fig. 15.

[0113] The first thickness region 70a is defined as the element coat 70 from the part of the element coat 70 closest to the intended electrode location R30 on the XIV-XIV cross section until the thickness of the element coat 70 reaches the maximum thickness T32 on the XIV-XIV cross section.

[0114] The second thickness region 70b is a portion of the element coating 70 on the XIV-XIV cross section where the thickness of the element coating 70 is the maximum thickness T32 on the XIV-XIV cross section. More strictly, the second thickness region 70b is defined as the portion of the element coating 70 on the XIV-XIV cross section that is located away from the planned electrode location R30, starting from the portion of the element coating 70 where the thickness of the element coating 70 is the maximum thickness T32 on the XIV-XIV cross section.

[0115] 16 is a cross-sectional view taken along the line XVI-XVI of FIG. 13. The XVI-XVI cross-section is a cross-section of the element body 2 cut in the longitudinal direction DL along a straight line perpendicular to the boundary between the external electrode 4 and the element body coating 70, as viewed from the end face 14. In the XVI-XVI cross-section, the DT direction is the direction away from the planned electrode location R30. As shown in FIG. 16, in the XVI-XVI cross-section, a sloped portion 73 is formed in the element body coating 70 in the boundary region between the planned electrode location R30 and the coating location R31, and the thickness of the element body coating 70 increases on average in the direction away from the planned electrode location R30. In other words, the sloped portion 73 is a portion in the XVI-XVI cross-section where the thickness of the element body coating 70 increases on average toward the second thickness region 70b. The inclined portion 73 is formed in the direction away from the predetermined electrode portion R30, from the boundary between the predetermined electrode portion R30 and the coating portion R31 to the position where the thickness of the element coat 70 becomes the maximum thickness T32 in the XVI-XVI cross section. Therefore, the inclined portion 73 is formed in the entire first thickness region 70a in the XVI-XVI cross section. Furthermore, in the XVI-XVI cross section, the flat portion 75 is not formed in the first thickness region 70a.

[0116] Furthermore, in the XVI-XVI cross section, the first thickness region 70a does not have a step portion 71 where the thickness changes suddenly. That is, the difference in thickness between the first thickness region 70a and the second thickness region 70b is formed by a slope portion 73, not a step portion 71 where the thickness of the element coating 70 changes suddenly. In the XVI-XVI cross section, the first thickness region 70a is the element coating 70 from the portion of the element coating 70 closest to the planned electrode location R30 to the portion where the thickness of the element coating 70 is the maximum thickness T32 in the XVI-XVI cross section. In addition, in the XVI-XVI cross section, the second thickness region 70b is the element coating 70 that is located away from the portion where the thickness of the element coating 70 is the maximum thickness T32 in the XVI-XVI cross section, away from the planned electrode location R30. By forming the inclined portion 73, even if the step portion 71 is not formed, it is possible to easily form the first thickness region 70a and the second thickness region 70b.

[0117] In this way, in the body coating 70, the first thickness region 70a and the second thickness region 70b may have a difference in thickness due to the step portion 71, or may have a difference in thickness due to the inclined portion 73. As in this embodiment, the body coating 70 of one inductor 1 may have a mixture of portions where the step portion 71 is formed and portions where the inclined portion 73 is formed, on each cut surface. Furthermore, the body coating 70 of one inductor 1 may be configured so that only either the step portion 71 or the inclined portion 73 is formed.

[0118] Up to this point, in [B-2-2. Configuration of external electrodes and element body coating], the explanation based on one end face 14 shown in FIG. 13 also applies to the other end face 14 on the opposite side of the element body 2.

[0119] Furthermore, in [B-2-2. Configuration of External Electrodes and Body Coating], the end faces 14 have been explained using Figures 13 to 16. Incidentally, when the element body 2 is viewed from the bottom face 10 side, the inductor 1 has an external electrode 4 located on one end face 14 side, an external electrode 4 located on the other end face 14 side, and an element body coating 70 surrounding these two external electrodes 4 (see Figure 2). Therefore, the explanation of the end faces 14 using Figures 13 to 16 above also applies to the bottom face 10. In other words, the explanation above using the cut faces of Figures 14 to 16 also applies to a cross section taken in the thickness direction DT of the element body 2 along a straight line perpendicular to the boundary between any one external electrode 4 and the element body coating 70 as viewed from the bottom face 10.

[0120] [Other embodiments] In the embodiment described above in [B-2-1. Configuration of Electrode Locations and External Electrode Connection Portions], the element coat 70 is described as having the first thickness region 70a and the second thickness region 70b, but this is just one example. The element coat 70 does not necessarily have to have either the first thickness region 70a or the second thickness region 70b.

[0121] In the embodiment described above in [B-2-2. Configuration of External Electrode and Body Coat], the tip 65a of the peripheral edge 65 of the external electrode 4 is located on the flat portion 75 of the first thickness region 70a, but this is just one example. For example, the tip 65a of the peripheral edge 65 may be located on the stepped portion 71.

[0122] In the embodiment shown above in [B-2-2. Configuration of the External Electrode and the Body Coating], it was explained that the thickness of the portion of the external electrode 4 formed on the surface of the element body 2 is greater than the thickness of the second thickness region 70b in the XIV-XIV cross section, but this is just one example. That is, in a cross section obtained by cutting the element body 2 in the longitudinal direction DL along a straight line perpendicular to the boundary between the external electrode 4 and the element body coating 70 as viewed from the end face 14, the thickness of the portion of the external electrode 4 formed on the surface of the element body 2 may be smaller than the thickness of the second thickness region 70b.

[0123] 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, perpendicular, 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.

[0124] [Configuration supported by the above embodiment] The above-described embodiment supports the following configurations.

[0125] (Configuration 1) An inductor comprising: an element body including a coil conductor, a core containing magnetic particles and resin in which the coil conductor is embedded; and external electrodes arranged on opposite end surfaces of the element body, wherein the coil conductor includes a winding portion in which a conductor wire is wound around a winding axis, a lead portion drawn out from the winding portion, and an external electrode connection portion which is a portion of the conductor wire that connects to the lead portion and is for connecting to an external electrode, wherein the boundary between the lead portion and the external electrode connection portion is a bent portion where the conductor wire is bent, and wherein, in a plan view seen from the normal direction of an upper surface that is perpendicular to the end surface of the element body, a first angle formed by the extension direction of the external electrode connection portion that extends from the bent portion as a starting point and the normal direction of the end surface that passes through the bent portion and points toward the interior of the element body is greater than 90 degrees.

[0126] (Configuration 2) An inductor as described in Configuration 1, comprising a pair of external electrodes arranged on each of a pair of opposing end faces of the element body, wherein the coil conductor includes a pair of lead-out portions that are drawn out from the winding portion to each of the end faces of the element body and electrically connected to the external electrodes, and a pair of external electrode connection portions that are portions of the conductor that are connected to each of the lead-out portions and to each of the external electrodes, and wherein the first angle is greater than 90 degrees in the pair of lead-out portions and the pair of external electrode connection portions.

[0127] (Configuration 3) An inductor according to configuration 1, wherein a second angle formed between the extension direction of the lead-out portion starting from the bent portion and the extension direction of the external electrode connection portion starting from the bent portion is greater than or equal to 150 degrees and less than 180 degrees.

[0128] (Configuration 4) The inductor according to any one of configurations 1 to 3, wherein the first angle is 100 degrees or less.

[0129] (Configuration 5) An inductor described in any of configurations 1 to 4, wherein the element body has a top surface and a bottom surface that face each other perpendicular to the pair of opposing end surfaces of the element body, and a pair of side surfaces that face each other perpendicular to the pair of end surfaces and the top surface and bottom surface, the coil conductor is embedded in the element body so that the winding axis is along the normal direction to the top surface, and the outline of the winding portion in a planar view seen from the normal direction to the top surface has a first length that is the maximum length in the direction perpendicular to the side surfaces and is equal to or greater than a second length that is the maximum length measured in the direction perpendicular to the end surfaces.

[0130] (Configuration 6) The inductor according to configuration 5, wherein the ratio of the first length to the second length is 1 or more and 1.5 or less.

[0131] (Configuration 7) An inductor described in configuration 5, wherein, in a planar view from the normal direction of the top surface of the element body, the bent portion has a width in a direction perpendicular to the pair of side surfaces, centered on a line passing through the center of the end face and parallel to the side surfaces, within a range that is 1 / 2 of the distance between the pair of side surfaces.

[0132] (Configuration 8) The inductor according to configuration 5, wherein the length of the external electrode connection portion is 30% to 50% of the distance between the pair of side surfaces of the end face.

[0133] (Configuration 9) The inductor according to configuration 5, wherein the element body has a longer distance between the pair of end faces than the distance between the pair of side faces in a plan view seen from the normal direction of the top surface.

[0134] (Configuration 10) An inductor described in any of configurations 1 to 9, wherein the element body has a top surface and a bottom surface that face each other perpendicular to the pair of opposing end surfaces of the element body, and a pair of side surfaces that face each other perpendicular to the pair of end surfaces and the top surface and bottom surface, and the element body has a distance between the pair of side surfaces that is 1.2 mm or more and 1.4 mm or less, and a distance between the pair of end surfaces that is 1.4 mm or more and 1.6 mm or less. [Explanation of symbols]

[0135] 1...inductor, 2...element body, 4...external electrode, 10...bottom surface, 12...top surface, 14...end surface, 16...side surface, 20...coil conductor, 22...winding portion, 22a, 22b...winding region, 23...lead portion, 24...external electrode connection portion, 30...core, 41a...top surface, 41b...bottom surface, 42...conductor, 43...conductor, 43a...inner surface of conductor, 43b...outer surface of conductor, 43c...side surface of conductor, 43d...side surface of conductor, 45...coating layer, 48...bent portion, 50...plated conductor, 51...copper plating layer (plating layer), 52...Ni plating layer, 53...tin Plating layer, 64a...peeled portion, 64b...coated portion, 64c...tip, 65...periphery, 65a...tip, 70...element coating, 70a...first thickness region, 70b...second thickness region, 71...step portion, 73...inclined portion, 75...flat portion, DT...thickness direction, K...winding axis, R...radius of curvature, R20, R21...range, R30...planned electrode location, R31...coated area, S1...circumscribed rectangle, S2...inscribed rectangle, T10...winding portion thickness, T11...top surface thickness (length), T12...bottom surface thickness (length), T11+T12...total value.

Claims

1. an element body including a coil conductor and a core including magnetic particles and a resin in which the coil conductor is embedded; a pair of external electrodes disposed on a pair of opposing end surfaces of the element body, Equipped with the coil conductor includes a winding portion in which a conductor wire is wound around a winding axis, a pair of lead-out portions that are led from the winding portion to each of the end faces of the element body and are electrically connected to the external electrodes, and external electrode connection portions that are connected to each of the lead-out portions and are portions of the conductor wire for connection to each of the external electrodes, the boundaries between the pair of lead portions and the pair of external electrode connection portions are bent portions where the conducting wire is bent, a first angle formed by an extension direction of the external electrode connection portion extending from the bent portion as a starting point and a normal direction of the end surface toward the inside of the element body through the bent portion in a plan view seen from a normal direction of an upper surface orthogonal to the end surface of the element body is greater than 90 degrees and is not greater than 100 degrees, a second angle formed by an extension direction of the lead portion starting from the bent portion and an extension direction of the external electrode connection portion starting from the bent portion is equal to or greater than 150 degrees and less than 180 degrees; the element body has a top surface and a bottom surface that are opposed to each other and perpendicular to the pair of opposed end surfaces of the element body, and a pair of side surfaces that are opposed to each other and perpendicular to the pair of end surfaces and the top surface and bottom surface, the coil conductor is embedded in the element body so that the winding axis is aligned along a normal direction to the upper surface, an outer shape of the winding portion in a plan view seen from a normal direction of the top surface has a first length that is a maximum length in a direction perpendicular to the side surface and is equal to or greater than a second length that is a maximum length measured in a direction perpendicular to the end surface; a side surface of the external electrode connection portion exposed at the end surface of the element body and electrically connected to the external electrode; Inductor.

2. a ratio of the first length to the second length is greater than or equal to 1 and less than or equal to 1.5; 10. The inductor of claim 1.

3. In a plan view seen from a normal direction of the top surface of the element body, the width of the bent portion in a direction perpendicular to the pair of side surfaces, centered on a line passing through a center of the end surface and parallel to the side surfaces, is within a range that is ½ of the distance between the pair of side surfaces.

10. The inductor of claim 1.

4. a length of the external electrode connection portion is 30% to 50% of the distance between the pair of side surfaces of the end surface; 10. The inductor of claim 1.

5. In a plan view of the element body seen from a normal direction of the top surface, a distance between the pair of end faces is longer than a distance between the pair of side faces.

10. The inductor of claim 1.

6. the element body has a top surface and a bottom surface that are opposed to each other and perpendicular to the pair of opposed end surfaces of the element body, and a pair of side surfaces that are opposed to each other and perpendicular to the pair of end surfaces and the top surface and bottom surface, The element body has a distance between the pair of side surfaces of 1.2 mm or more and 1.4 mm or less, and a distance between the pair of end surfaces of 1.4 mm or more and 1.6 mm or less.

6. An inductor according to claim 1.

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