Coil Device

Abstract

To provide a coil device that can prevent generation of short circuit failures and contribute to reduction in man hours and improvement in quality.SOLUTION: An inductor 1 has: a coil 2; terminals 4a and 4b each of which comprises a wire joint part 42a, 42b connected with a lead-out part 3a, 3b of the coil 2, and a base part 41a, 41b located at a height substantially equal to that of a bottom face of the coil 2 and holding the wire joint part 42a, 42b; and a core 8 that covers the coil 2 together with the wire joint parts 42a and 42b and the base parts 41a and 41b. Each base part 41a, 41b has a main branch part 410a, 410b and a sub-branch part 411a, 411b. A curved part 414a, 414b curved along the outer peripheral surface 2e of the coil 2 at a position separated from the outer peripheral surface 2e of the coil 2 is formed at an inner edge 410a2, 410b2 of the main branch part 410a, 410b. A curved part 415a, 415b curved along the outer peripheral surface 2e of the coil 2 at a position separated from the outer peripheral surface 2e of the coil 2 is formed at an inner edge 411a2, 411b2 of the sub-branch part 411a, 411b.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a coil device used as, for example, an inductor. [Background technology]

[0002] As a coil device known as an inductor or the like, for example, the coil device described in Patent Document 1 is known. The coil device described in Patent Document 1 has an element body, a coil arranged inside the element body, and a terminal to which the lead-out portion of the coil is connected. The terminal has a connection portion to which the lead-out portion of the coil is connected, as well as a base portion (coil fixing portion) that holds the connection portion. The base portion is arranged inside the element body, and the coil can be placed on the upper surface of the base portion.

[0003] The coil device described above is obtained by placing the coil and terminals inside a mold, filling it with the magnetic material that constitutes the element body, and compression molding the result. As described above, placing the coil on the top surface of the base has the advantage of preventing the coil from shifting in position due to the applied pressure during compression molding.

[0004] However, when a coil is placed on the top surface of the base, the following problem may occur. The conductor portion of the coil is usually covered with an insulating coating, but damage to the insulating coating may expose the conductor portion. In this case, the base and the exposed conductor portion of the coil may come into contact directly or through the plating on the surface of the base or metal powder in the element, which may cause a short circuit between the conductor portion of the coil and the terminal.

[0005] To avoid this problem, it is conceivable to position the coil at a distance above the top surface of the base, rather than placing the coil on the top surface of the base, thereby forcibly avoiding physical contact between the top surface of the base and the bottom surface of the coil. However, in this case, the coil is positioned far from the terminal (particularly the wire connection portion), and processing such as bending the lead-out portion is required to lead the lead-out portion to the position of the wire connection portion of the terminal. Such processing is undesirable because it increases the number of steps and reduces the quality of the coil device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-133402 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coil device that prevents the occurrence of short-circuit defects and contributes to reducing the number of steps and improving quality. [Means for solving the problem]

[0008] In order to achieve the above object, a coil device according to the present invention comprises: A coil and a terminal including a connecting portion connected to the lead-out portion of the coil and a base portion positioned at substantially the same height as the bottom surface of the coil and holding the connecting portion; an element body that covers the coil together with the connection portion and the base portion, the base portion has a main branch portion and a sub-branch portion; The main branch and the sub-branch have inner edges formed with curved portions that curve along the outer circumferential surface of the coil at positions spaced apart from the outer circumferential surface of the coil.

[0009] In the coil device according to the present invention, the base portion is located at a height substantially equal to the bottom surface of the coil, so the coil can be drawn out to the position of the connection portion and connected thereto without unnecessary bending of the lead-out portion of the coil. This reduces damage to the lead-out portion of the coil and allows for a high-quality coil device. Furthermore, unnecessary processing (bending) of the coil can be avoided, thereby reducing the number of steps.

[0010] Furthermore, because the inner edges (curved portions) of the main branch and sub-branch are positioned away from the outer circumferential surface of the coil, there is no physical contact between the main branch and sub-branch and the coil, ensuring sufficient voltage resistance between them. This avoids the problem of the prior art mentioned above (the problem of short circuits occurring between the conductor portion of the coil and the terminal due to physical contact caused by damage to the insulating coating of the coil).

[0011] Furthermore, because the inner edges (curved portions) of the main branch and sub-branch are curved along the outer circumferential surface of the coil, the main branch and sub-branch, as well as the connecting portion, can be positioned relatively close to the outer circumferential surface of the coil, making it possible to make the base portion or connecting portion more compact.Furthermore, the volume of the coil can be increased by the amount that the base portion or connecting portion is made more compact, thereby improving the inductance characteristics of the coil device.

[0012] Preferably, the main branch has a main protrusion protruding toward the front of the element body, and the sub-branch has a sub-protrusion protruding toward the rear of the element body, with one of the main protrusion and the sub-protrusion being offset in position from the other of the main protrusion and the sub-protrusion in a left-right direction perpendicular to the front-rear direction of the element body. With this configuration, the anchor effect provided by the main protrusion and the sub-protrusion can prevent the terminal from coming off the element body or the base from shifting in position within the element body, particularly in the left-right direction of the element body. Furthermore, by offsetting one of the main protrusion and the sub-protrusion from the other in the left-right direction of the element body, it is possible to ensure a sufficient area occupied by the main protrusion and the sub-protrusion within the element body, thereby effectively achieving the above-mentioned effects.

[0013] Preferably, the outer edge of the main branch portion curves from the side of the element body toward the front within the element body, and the outer edge of the sub-branch portion curves from the side of the element body toward the rear within the element body, with the radius of curvature of the outer edge of the main branch portion being different from the radius of curvature of the outer edge of the sub-branch portion. This configuration provides an anchor effect provided by the main branch portion and the sub-branch portion, preventing the terminal from coming off the element body and preventing the base portion from shifting position within the element body, particularly in the left-right direction of the element body. Furthermore, by making the radius of curvature of the outer edge of the main branch portion different from the radius of curvature of the outer edge of the sub-branch portion, the main branch portion or the sub-branch portion is provided with a size sufficient to achieve the above-mentioned effects, and the above-mentioned effects can be effectively obtained.

[0014] Preferably, the terminal includes a first terminal and a second terminal, the first terminal has a first base portion; the second terminal has a second base portion; the first base portion has a first main branch portion and a first sub-branch portion; the second base portion has a second main branch portion and a second sub-branch portion; the curved portion comprises a first main curved portion formed on the inner edge of the first main branch portion, a first sub-curved portion formed on the inner edge of the first sub-branch portion, a second main curved portion formed on the inner edge of the second main branch portion, and a second sub-curved portion formed on the inner edge of the second sub-branch portion, The center position of an imaginary circle defined by the first major curved portion, the first minor curved portion, the second major curved portion, and the second minor curved portion substantially coincides with the center position of the inner circumference of the coil.

[0015] This configuration makes it possible to maintain a substantially constant clearance between the outer circumferential surface of the coil and the inner edges of the first base portion (first main branch portion and first sub-branch portion), and also to maintain a substantially constant clearance between the outer circumferential surface of the coil and the inner edges of the second base portion (second main branch portion and second sub-branch portion). This prevents variations in inductance characteristics from occurring between individual products. Furthermore, it prevents the formation of locally low-voltage-resistance regions between the first and second base portions and the coil, thereby promoting quality improvement of the coil device.

[0016] Preferably, the top surface of the base portion and the bottom surface of the coil are located on approximately the same plane, and on the approximately same plane, the distance between the first major curved portion and the outer peripheral surface of the coil, the distance between the first minor curved portion and the outer peripheral surface of the coil, the distance between the second major curved portion and the outer peripheral surface of the coil, and the distance between the second minor curved portion and the outer peripheral surface of the coil are approximately equal. If the top surface of the base portion and the bottom surface of the coil are located on approximately the same plane, the coil's lead-out portion can be extended to the connection portion and connected thereto without unnecessary bending. This is particularly advantageous when the coil is formed from a flat wire, which is not easy to process, and contributes to improving the quality of the coil device. Furthermore, the above-described configuration makes it possible to maintain a substantially constant clearance between the outer peripheral surface of the coil and the inner edges of the first base portion and the second base portion (the first major curved portion, the first minor curved portion, the second major curved portion, and the second minor curved portion), further improving the quality of the coil device.

[0017] Preferably, a portion of the connection portion is disposed at a position spaced above the upper surface of the base portion. With this configuration, when the lead-out portion of the coil is led out at a position spaced above the upper surface of the base portion, the lead-out portion of the coil can be led out to the position of the connection portion and connected to it without unnecessary bending.

[0018] Preferably, the center position of the coil is offset from the center of the element body in the front-to-rear direction of the element body to the side opposite the wire connection portion. This configuration allows a sufficient volume of the element body to be secured in front of the element body (the side where the wire connection portion is located). Therefore, the wire connection portion and the lead-out portion of the coil connected thereto can be covered and protected by a sufficient amount of element body. Furthermore, because sufficient space is provided in front of the element body to accommodate the wire connection portion, there is no need to extend the element body outward (forward) to secure this space, which allows for a more compact coil device.

[0019] Preferably, the coil is made of rectangular wire. With this configuration, a relatively large current can be passed through the coil, and deformation of the coil is less likely to occur, resulting in a high-quality coil device. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view of a coil device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing the internal configuration of the coil device shown in FIG. [Figure 3] FIG. 3 is a perspective view of the coil shown in FIG. [Figure 4] FIG. 4 is a perspective view of the pair of terminals shown in FIG. [Figure 5A] FIG. 5A is a side view showing a state in which the lead-out portion of the coil is connected to the pair of terminals shown in FIG. [Figure 5B] FIG. 5B is a perspective view showing the pair of terminals and the coil shown in FIG. 5A when viewed from a different angle. [Figure 6] FIG. 6 is a plan view showing the coil device shown in FIG. 2 as viewed from the bottom. [Figure 7A] FIG. 7A is a diagram showing a method of manufacturing the coil device shown in FIG. [Figure 7B] FIG. 7B is a diagram showing a process subsequent to that shown in FIG. 7A. [Figure 7C] FIG. 7C is a diagram showing a process subsequent to that shown in FIG. 7B. [Figure 7D] FIG. 7D shows a process subsequent to that shown in FIG. 7C. [Figure 7E] FIG. 7E shows a process subsequent to that shown in FIG. 7D. [Figure 7F] FIG. 7F shows a process subsequent to that shown in FIG. 7E. [Figure 8] FIG. 8 is a perspective view of a coil device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, the present invention will be described based on the embodiments shown in the drawings.

[0022] First embodiment As shown in Fig. 1, the inductor 1 according to the first embodiment of the present invention is a surface-mounted inductor having a substantially rectangular parallelepiped shape. In Fig. 1, the surface of the inductor 1 on the negative side of the Z axis is the mounting surface 8a, which is disposed facing a circuit board or the like. Hereinafter, the surface of the inductor 1 opposite the mounting surface 8a will be referred to as the non-mounting surface 8b. In the drawing, the X-axis direction corresponds to the left-right direction of the core 8, the Y-axis direction corresponds to the front-rear direction of the core 8, and the Z-axis direction corresponds to the up-down direction of the core 8.

[0023] As shown in Fig. 2, the inductor 1 has a coil 2, a pair of terminals 4a and 4b, and a core (element body) 8. Note that Fig. 2 shows the inductor 1 shown in Fig. 1 in a state in which it has been inverted vertically and horizontally. Therefore, the mounting surface 8a of the inductor 1 is located at the top of the page, and the non-mounting surface 8b of the inductor 1 is located at the bottom of the page.

[0024] For ease of understanding, the following description will be made assuming that the upper side of the paper (the negative Z-axis side in FIG. 2) is the top of inductor 1, and the lower side of the paper (the positive Z-axis side in FIG. 2) is the bottom of inductor 1. Also, the description will be made assuming that the front side of the paper (the positive Y-axis side in FIG. 2) is the front of inductor 1, and the back side of the paper (the negative Y-axis side in FIG. 2) is the rear of inductor 1. Also, the direction away from the center of core 8 or coil 2 is the outside, and the direction toward the center of core 8 or coil 2 is the inside.

[0025] The dimensions of inductor 1 are not particularly limited, but its width in the X-axis direction is preferably 2 to 20 mm, its width in the Y-axis direction is preferably 2 to 20 mm, and its width in the Z-axis direction is preferably 1 to 10 mm.

[0026] The core 8 is made of a mixture containing magnetic powder and binder resin, and is formed by combining the first core 5 and second core 6 shown in Fig. 7C. That is, the core 8 is formed by compressing the preformed first core 5 and second core 6 inside a mold and integrating them. Note that the boundary between the first core 5 and second core 6 is indistinguishable, and they are integrated into one piece.

[0027] The core 8 (first core 5 and / or second core 6) is made of a synthetic resin in which ferrite particles or metal magnetic particles are dispersed. However, the material constituting the core 8 is not limited to this, and the core 8 may be made of a synthetic resin that does not contain these particles. Examples of ferrite particles include Ni-Zn ferrite and Mn-Zn ferrite. Examples of metal magnetic particles include, but are not limited to, Fe-Ni alloy powder, Fe-Si alloy powder, Fe-Si-Cr alloy powder, Fe-Co alloy powder, Fe-Si-Al alloy powder, and amorphous iron.

[0028] The synthetic resin contained in the core 8 is not particularly limited, but preferable examples include epoxy resin, phenol resin, polyester resin, polyurethane resin, polyimide resin, and silicone resin.

[0029] As shown in FIG. 3, the coil 2 is a flatwise coil. The coil 2 is formed by, for example, α-winding a wire 3 made of a rectangular wire, and is configured in two layers along the Z-axis direction. By forming the coil 2 from a rectangular wire, a relatively large current can be passed through the coil 2, and deformation of the coil 2 is less likely to occur, resulting in a high-quality inductor 1. Note that the winding method of the wire 3 is not limited to α-winding and may be changed as appropriate.

[0030] The winding axis direction of the coil 2 corresponds to the Z-axis direction. The wire 3 is wound so that of the four side surfaces that make up the outer surface of the rectangular wire, the two relatively wider surfaces face the inner and outer peripheries of the coil 2. Note that the coil 2 may also be formed as an edgewise coil by winding the wire so that of the four side surfaces that make up the outer surface of the rectangular wire, the two relatively narrower surfaces face the inner and outer peripheries of the coil 2.

[0031] The coil 2 is an air-core coil, and as shown in Fig. 2, the coil 2 is embedded inside the core 8. The coil 2 is disposed inside the core 8 so that the thickness direction of the lead-out portions 3a and 3b is approximately aligned with the X-axis direction (the left-right direction of the core 8).

[0032] The wire 3 may be made of any suitable conductive material, such as copper, copper alloy, silver, or nickel. The wire 3 is not particularly limited as long as it is a conductive material. The wire 3 is an insulating-coated wire, with an insulating coating 30 formed on the surface of the wire 3. The resin that forms the insulating coating 30 is not particularly limited, but examples include polyamide-imide resin and urethane resin. Alternatively, the wire 3 may be a self-bonding wire with a fusion coating on the outside of the insulating coating. The resin that forms the fusion coating is not particularly limited, but examples include polyamide resin and epoxy resin. The insulating coating 30 is removed from the wire 3 at the lead-out portions 3a and 3b to allow electrical connection with the terminals 4a and 4b.

[0033] As shown in FIG. 3, the lead-out portion 3a of the wire 3 is drawn out from the coil 2 from a first lead-out position 2c located on the outer peripheral surface 2e of the coil 2 in the second layer of the coil 2, and extends linearly along the Y-axis direction. The lead-out portion 3b of the wire 3 is drawn out from a second lead-out position 2d located on the outer peripheral surface 2e of the coil 2 in the first layer of the coil 2, and extends linearly along the Y-axis direction. The lead-out portions 3a and 3b are drawn out in the same direction (the Y-axis direction) without being twisted or bent. The first lead-out position 2c and the second lead-out position 2d are offset from each other along the Z-axis direction, and the lead-out portions 3a and 3b are arranged with an offset from each other along the Z-axis direction.

[0034] In the state shown in FIG. 3, the lead-out portions 3a and 3b are drawn out along the Y-axis direction, but when connected to the connecting wire portions 42a and 42b, the lead-out portions 3a and 3b are inclined inward with respect to the Y-axis.

[0035] 4, terminal 4a has a base portion 41a, a wire connection portion 42a, a connection portion 43a, and a mounting portion 44a. Terminal 4b has a base portion 41b, a wire connection portion 42b, a connection portion 43b, and a mounting portion 44b. Terminals 4a and 4b are formed by machining a conductive plate material such as a metal.

[0036] 5A, the base portions 41a, 41b are located at approximately the same height as the bottom surface 2b of the coil 2, and are disposed approximately parallel to the bottom surface (opposite mounting surface 8b) of the core 8 shown in FIG. 2. In this embodiment, the upper surfaces of the base portions 41a, 41b and the bottom surface of the coil 2 are located on approximately the same plane. Wire connection portions 42a, 42b are formed integrally with the base portions 41a, 41b, and the base portions 41a, 41b play a role in holding the wire connection portions 42a, 42b.

[0037] As shown in Figure 4, the base portion 41a has a main branch portion 410a and a sub-branch portion 411a, and the base portion 41b has a main branch portion 410b and a sub-branch portion 411b. Both the base portions 41a and 41b have a bifurcated shape and share a common shape with some exceptions. The explanation of the base portion 41a (the main branch portion 410a and the sub-branch portion 411a) also applies to the base portion 41b (the main branch portion 410b and the sub-branch portion 411b), so only the particularly necessary points will be explained regarding the latter.

[0038] The end of main branch 410a (more specifically, main protrusion 412a, described later) on the positive side of the Y axis is connected to connecting wire portion 42a, and main branch 410a holds connecting wire portion 42a. The ends of main branch 410a and sub-branch 411a on the negative side of the X axis are both connected to the lower end of connecting portion 43a. Main branch 410a extends further outward in the Y axis direction than the end of connecting portion 43a on the positive side of the Y axis, and sub-branch 411a extends further outward in the Y axis direction than the end of connecting portion 43a on the negative side of the Y axis.

[0039] A groove 45a is formed between the main branch 410a and the sub branch 411a. The groove 45a forms a gap between the main branch 410a and the sub branch 411a so that the base 41a has a bifurcated shape.

[0040] The main branch 410a is located further in the positive direction of the Y axis than the groove 45a, and the sub-branch 411a is located further in the negative direction of the Y axis than the groove 45a. The main branch 410a and the sub-branch 411a are each bent in a generally L-shape overall. That is, the main branch 410a extends inward in the X axis direction from the lower end of the connecting portion 43a, then changes direction to the Y axis and extends toward the positive direction of the Y axis. The sub-branch 411a extends inward in the X axis direction from the lower end of the connecting portion 43a, then changes direction to the Y axis and extends toward the negative direction of the Y axis.

[0041] 6, the main branch 410a and the sub branch 411a extend away from each other inside the core 8. That is, the main branch 410a extends so as to bend forward from the side of the core 8. The sub branch 411a extends so as to bend backward from the side of the core 8. The core 8 covers the coil 2 together with the connecting portion 42a and the base portion 41a (the main branch 410a and the sub branch 411a).

[0042] The outer edge 410a1 of the main branch 410a is smoothly curved from the side of the core 8 toward the front, in accordance with the overall shape of the main branch 410a. The outer edge 411a1 of the sub branch 411a is smoothly curved from the side of the core 8 toward the rear, in accordance with the overall shape of the sub branch 411a. The radius of curvature R1 of the outer edge 410a1 of the main branch 410a is different from the radius of curvature R2 of the outer edge 411a1 of the sub branch 411a. In this embodiment, R1>R2, but R1 <R2としてもよい。

[0043] By curving the outer edge 410a1 of the main branch 410a and the outer edge 411a1 of the sub-branch 411a, the anchor effect provided by the main branch 410a and the sub-branch 411a can prevent the terminal 4a from coming off the core 8 and the base 41a from shifting position within the core 8, particularly in the left-right direction of the core 8. Furthermore, by making the radius of curvature of the outer edge 410a1 of the main branch 410a and the radius of curvature of the outer edge 411a1 of the sub-branch 411a different, the main branch 410a and the sub-branch 411a are provided with sizes sufficient to provide the above-mentioned effects, and the above-mentioned effects can be effectively obtained.

[0044] The main branch 410a has a main protrusion 412a that protrudes (extends) toward the front of the core 8. The sub-branch 411a has a sub-protrusion 413a that protrudes (extends) toward the rear of the core 8. The main branch 410b has a main protrusion 412b that protrudes toward the front of the core 8. The sub-branch 411b has a sub-protrusion 413b that protrudes toward the rear of the core 8.

[0045] The main protrusion 412a is thinner than the other parts of the main branch 410a, and the sub-protrusion 413a is thinner than the other parts of the sub-branch 411a. The sub-branch 411a is also thinner in the X-axis direction than the main branch 410a.

[0046] The main protrusion 412a protrudes in the Y-axis direction further forward from the core 8 than the outer peripheral surface 2e of the coil 2. In contrast, the sub-protrusion 413a protrudes in the Y-axis direction further rearward from the core 8 than the inner peripheral surface 2f of the coil 2, but does not protrude further rearward from the core 8 than the outer peripheral surface 2e of the coil 2. In other words, the end of the sub-protrusion 413a in the Y-axis direction is located between the inner peripheral surface 2f and the outer peripheral surface 2e of the coil 2 in the Y-axis direction.

[0047] One of the main protrusion 412a and the sub-protrusion 413a is offset in position from the other along the X-axis direction of the core 8. In this embodiment, the sub-protrusion 413a is offset outward in the X-axis direction of the core 8 from the main protrusion 412a. That is, the inner edge of the sub-protrusion 413a is positioned further outward from the core 8 than the inner edge of the main protrusion 412a, and the outer edge of the sub-protrusion 413a is positioned further outward from the core 8 than the outer edge of the main protrusion 412a.

[0048] Providing the base portion 41a with the main protrusion 412a and the sub-protrusion 413a provides an anchor effect that prevents the terminal 4a from coming off the core 8 and the base portion 41a from shifting position within the core 8, particularly in the left-right direction of the core 8. Furthermore, by shifting one of the main protrusion 412a and the sub-protrusion 413a more than the other in the left-right direction of the core 8, it is possible to ensure a sufficient area occupied by the main protrusion 412a and the sub-protrusion 413a within the core 8, and the above-mentioned effects can be effectively obtained.

[0049] 4, a main curved portion 414a is formed at the inner edge 410a2 of the main branch portion 410a, and a sub-curved portion 415a is formed at the inner edge 411a2 of the sub-branch portion 411a. Also, a main curved portion 414b is formed at the inner edge 410b2 of the main branch portion 410b, and a sub-curved portion 415b is formed at the inner edge 411b2 of the sub-branch portion 411b.

[0050] The main curved portions 414a and 414b are formed mainly in the main branch portions 410a and 410b, excluding the main protrusions 412a and 412b. The sub curved portions 415a and 415b are formed mainly in the sub branch portions 411a and 411b, excluding the sub protrusions 413a and 413b.

[0051] The radius of curvature of the main curved portion 414a, the radius of curvature of the secondary curved portion 415a, the radius of curvature of the main curved portion 414b, and the radius of curvature of the secondary curved portion 415b are all approximately equal. Furthermore, these radii of curvature are also approximately equal to the radius of curvature of the outer periphery (outer periphery surface 2e) or inner periphery (inner periphery surface 2f) of the coil 2. Therefore, the main curved portions 414a, 414b and the secondary curved portions 415a, 415b are curved along the outer periphery surface 2e of the coil 2 at positions spaced a predetermined distance from the outer periphery surface 2e of the coil 2.

[0052] 6, the inner edge 410a2 of the main branch 410a faces the outer peripheral surface 2e of the coil 2 at a predetermined distance D1. The inner edge 411a2 of the sub-branch 411a faces the outer peripheral surface 2e of the coil 2 at a predetermined distance D2. The inner edge 410b2 of the main branch 410b faces the outer peripheral surface 2e of the coil 2 at a predetermined distance D3. The inner edge 411b2 of the sub-branch 411b faces the outer peripheral surface 2e of the coil 2 at a predetermined distance D4. In other words, none of the main branches 410a, 410b and the sub-branches 411a, 411b are in contact with the coil 2, but are arranged around the outer peripheral surface 2e of the coil 2 so as to surround the outer peripheral surface 2e of the coil 2. In this embodiment, on an imaginary plane parallel to the bottom surface 2b of the coil 2 and the upper surfaces of the base portions 41a and 41b, the distances D1, D2, D3, and D4 are approximately equal.

[0053] The center position of an imaginary circle C defined by the main curved portion 414a, the sub curved portion 415a, the main curved portion 414b, and the sub curved portion 415b substantially coincides with the center position of the inner periphery (inner circumferential surface 2f) or the outer periphery (outer periphery surface 2e) of the coil 2. In other words, the imaginary circle C and the imaginary circle defined by the inner periphery (inner circumferential surface 2f) or the outer periphery (outer periphery surface 2e) of the coil 2 are arranged concentrically.

[0054] 5A, the inner edge 410a2 of the main branch portion 410a is located further outward in the X-axis direction than the inner surface 3a2 of the lead-out portion 3a. Although not shown in detail, the inner edge 411a2 (FIG. 4) of the sub branch portion 411a is also located further outward in the X-axis direction than the inner surface 3a2 of the lead-out portion 3a. In other words, the main branch portion 410a and the sub branch portion 411a do not protrude inward beyond the inner surface 3a2 of the lead-out portion 3a.

[0055] Furthermore, an inner edge 410b2 of the main branch portion 410b is located further outward in the X-axis direction than the inner surface 3b2 of the lead-out portion 3b. Although not shown in detail, an inner edge 411b2 (FIG. 4) of the sub branch portion 411b is also located further outward in the X-axis direction than the inner surface 3b2 of the lead-out portion 3b. In other words, the main branch portion 410b and the sub branch portion 411b do not protrude inward beyond the inner surface 3b2 of the lead-out portion 3b.

[0056] Of the main branch portions 410a and 410b, the lead-out bottom portion 3b1 of the lead-out portion 3b, which is led out from below the coil 2 (second lead-out position 2d), is placed on the top surface of the main branch portion 410b. As a result, the lead-out portion 3b is fixed to the main branch portion 410b, which effectively prevents displacement of the lead-out portion 3b (and even the entire coil 2) due to pressure during manufacturing of the inductor 1 (during compression molding of the first core 5 and second core 6 shown in FIG. 7C). Note that, because the lead-out portion 3a of the wire 3 is led out from above the coil 2 (first lead-out position 2c), it is not placed on the top surface of the main branch portion 410a but is positioned above and spaced apart from the top surface of the main branch portion 410a.

[0057] 4, of the main branch portion 410a and the main branch portion 410b, a recess 416b is formed only in the main branch portion 410b. The recess 416b is formed on the inner edge 410b2 of the main branch portion 410b and is located at a different position from the main curved portion 414b (forward of the main curved portion 414b). The recess 416b is provided to adjust (narrow) the width in the X-axis direction of the main protrusion 412b and further the connecting portion 42b.

[0058] The connection portions 42a, 42b have a flat plate shape substantially parallel to the XZ plane and are arranged so as to be substantially perpendicular to the lead-out portions 3a, 3b (see FIG. 5B). As shown in FIG. 2, the connection portions 42a, 42b are arranged inside the core 8. The lead-out portions 3a, 3b of the wire 3 are connected to the connection portions 42a, 42b. More specifically, the lead-out portion 3a is connected to the connection portion 42a at a position spaced above the upper surface of the base portion 41a. The lead-out portion 3b is connected to the connection portion 42b while being placed on the base portion 41b. In this embodiment, the lead-out portions 3a, 3b are led out in substantially the same direction (the positive Y-axis direction), and therefore the connection portions 42a, 42b are arranged on the positive Y-axis side of the coil 2 from which the lead-out portions 3a, 3b are led out.

[0059] As shown in FIG. 4, the connection wire portions 42a, 42b extend along the Z-axis direction and rise upward from the ends of the main branches 410a, 410b on the positive side of the Y-axis. The connection wire portions 42a, 42b are arranged substantially perpendicular to the main branches 410a, 410b. The rising positions of the connection wire portions 42a, 42b are located forward of the ends of the connection portions 43a, 43b on the positive side of the Y-axis. As shown in FIG. 2, the ends of the base portions 41a, 41b on the positive side of the Y-axis are located outside the end of the coil 2 on the positive side of the Y-axis, and therefore the rising positions of the connection wire portions 42a, 42b are located outside the end of the coil 2 on the positive side of the Y-axis.

[0060] 5A, the length in the Z-axis direction of connection portion 42a is longer than the length in the Z-axis direction of connection portion 42b. The length in the Z-axis direction of connection portion 42a is longer than the length in the Z-axis direction of wire 3, and the upper end portion of connection portion 42a is disposed at a position corresponding to the second layer (first lead-out position 2c) of coil 2. Therefore, when lead-out portion 3a is led out from first lead-out position 2c, lead-out portion 3a can be led out to the position of connection portion 42a and connected thereto without unnecessary bending.

[0061] The length of connecting wire portion 42b in the Z-axis direction is shorter than the length of wire 3 in the Z-axis direction, and the upper end portion of connecting wire portion 42b is disposed at a position corresponding to the first layer (second lead-out position 2d) of coil 2. Therefore, the positions of the upper ends of connecting wire portions 42a and 42b are misaligned along the Z-axis direction.

[0062] In this way, the positions (heights) of the connection wire portions 42a, 42b are adjusted to match the positions (heights) of the pull-out positions 2c, 2d, so that the pull-out portions 3a, 3b can be pulled out to the position of the connection wire portions 42a, 42b and connected thereto without unnecessary bending.

[0063] As shown in FIG. 6, the position of the center O of the coil 2 is shifted along the Y-axis direction from the center of the core 8 to the opposite side from the connection portions 42a and 42b (rearward of the core 8). With this configuration, it is possible to ensure a sufficient volume of the core 8 in front of the core 8. Therefore, the connection portions 42a and 42b and the lead-out portions 3a and 3b connected thereto can be covered and protected by a sufficient amount of the core 8. Furthermore, because sufficient space is created in front of the core 8 to arrange the connection portions 42a and 42b, there is no need to extend the core 8 forward to ensure this space, and the inductor 1 can be made smaller.

[0064] In addition, it is possible to position the outer surface 2e of the coil 2 at a position sufficiently spaced from the side surface of the core 8 on the positive side of the Y axis, thereby ensuring sufficient thickness of the core 8 between the outer surface 2e of the coil 2 and the side surface of the core 8 on the positive side of the Y axis, and preventing cracks from occurring on the side surface of the core 8 on the positive side of the Y axis.

[0065] As shown in FIG. 5A , when the core 8 is viewed from the front, at least a portion of the lead-out portion 3a is located more inward in the X-axis direction than a first lead-out position 2c on the outer peripheral surface 2e of the coil 2 from which the lead-out portion 3a is led. Furthermore, at least a portion of the lead-out portion 3b is located more inward in the X-axis direction than a second lead-out position 2d on the outer peripheral surface 2e of the coil 2 from which the lead-out portion 3b is led. With this configuration, an elastic force acts on the lead-out portion 3a to return to the first lead-out position 2c (outside in the X-axis direction), so that the lead-out portion 3a is fixed to the connection portion 42a in a biased state. Similarly, an elastic force acts on the lead-out portion 3b to return to the second lead-out position 2d (outside in the X-axis direction), so that the lead-out portion 3b is fixed to the connection portion 42b in a biased state. Therefore, a good connection can be maintained between the lead-out portion 3a and the connection portion 42a, and a good connection can be maintained between the lead-out portion 3b and the connection portion 42b.

[0066] Of the connecting wire portions 42a and 42b, a notch 420a cut along the Z-axis direction is formed on the inner edge of the connecting wire portion 42a. The notch 420a is cut downward from the upper end of the connecting wire portion 42a to a predetermined depth. The lead-out portion 3a of the wire 3 can be fixed to the notch 420a.

[0067] The length of the cutout 420a in the Z-axis direction is approximately the same as the length of the wire 3 in the Z-axis direction. As shown in Fig. 5A, the lead-out bottom 3a1 of the lead-out portion 3a is fixed at a position spaced above the cutout bottom 421a and is not in contact with the cutout bottom 421a. Therefore, when the lead-out portion 3a is fixed in the cutout 420a, the upper end of the lead-out portion 3a protrudes above the upper end of the connecting portion 42a, and the lead-out portion 3a is not entirely housed inside the cutout 420a.

[0068] By fixing the lead-out portion 3a at a position spaced above the notch bottom 421a in this way, even if the first lead-out position 2c of the lead-out portion 3a moves along the Z-axis direction, the lead-out portion 3a will not come into contact with the notch bottom 421a, and the lead-out portion 3a can be reliably fixed to the notch 420a. Furthermore, when connecting the lead-out portion 3a to the connecting wire portion 42a, the lead-out portion 3a can be fixed to the notch 420a in a linearly drawn-out state without bending the lead-out portion 3a.

[0069] Like the upper end of the lead-out portion 3a, the upper end of the lead-out portion 3b also protrudes above the upper end of the connecting portion 42b because the length of the connecting portion 42b in the Z-axis direction is shorter than the length of the wire 3 in the Z-axis direction due to the miniaturization of the connecting portion 42b.

[0070] The inner edge of the connecting portion 42a is connected to the outer surface 3a3 of the lead-out portion 3a (more specifically, a part or most of the outer surface 3a3), and the inner edge of the connecting portion 42b is connected to the outer surface 3b3 of the lead-out portion 3b (more specifically, a part or most of the outer surface 3b3). The inner surface 3a2 of the lead-out portion 3a is not fixed to the connecting portion 42a, and the inner surface 3b2 of the lead-out portion 3b is not fixed to the connecting portion 42b.

[0071] In the X-axis direction, the outer surface 3a3 of the lead-out portion 3a is located more inward than the outer peripheral surface 2e of the coil 2 at the first lead-out position 2c. Therefore, in the X-axis direction, the inner edge of the connecting portion 42a is located between the outer surface 3a3 of the lead-out portion 3a and the outer peripheral surface 2e at the first lead-out position 2c. In addition, in the X-axis direction, the outer surface 3b3 of the lead-out portion 3b is located more inward than the outer peripheral surface 2e of the coil 2 at the second lead-out position 2d. Therefore, in the X-axis direction, the inner edge of the connecting portion 42b is located between the outer surface 3b3 of the lead-out portion 3b and the outer peripheral surface 2e at the second lead-out position 2d.

[0072] In this embodiment, the connecting wire portion 42a is positioned more outward in the X-axis direction than the lead-out portion 3a, which is led out in front of the core 8. Similarly, the connecting wire portion 42b is positioned more outward in the X-axis direction than the lead-out portion 3b, which is also led out in front of the core 8. More specifically, the inner edge of the connecting wire portion 42a is positioned more outward in the X-axis direction than the inner surface 3a2 of the lead-out portion 3a. Furthermore, the inner edge of the connecting wire portion 42a is positioned more outward in the X-axis direction than the outer surface 3a3 of the lead-out portion 3a at the position of the notch 420a. Furthermore, the inner edge of the connecting wire portion 42b is positioned more outward in the X-axis direction than the inner surface 3b2 and the outer surface 3b3 of the lead-out portion 3a. That is, the connecting wire portions 42a, 42b do not protrude inward in the X-axis direction beyond the inner surfaces 3a2, 3b2 of the lead-out portions 3a, 3b, and the entire connecting wire portions 42a, 42b are positioned outward in the X-axis direction beyond the inner surfaces 3a2, 3b2.

[0073] As shown in FIG. 2 , the lead portions 3a and 3b are connected to the connection portions 42a and 42b via fusion zones 9. The fusion zones 9 are formed by weld beads formed when the terminals 4a and 4b (connection portions 42a and 42b) are irradiated with a laser. However, the fusion zones 9 may also be connection members made of solder, conductive adhesive, or the like. In the connection portion 42a, the fusion zone 9 is located more outward in the X-axis direction than the inner surface 3a2 of the lead portion 3a. In the connection portion 42b, the fusion zone 9 is located more outward in the X-axis direction than the inner surface 3b2 of the lead portion 3b. That is, the fusion zones 9 do not substantially protrude (are not formed) inward in the X-axis direction than the inner surfaces 3a2 and 3b2 of the lead portions 3a and 3b, and the entire fusion zones 9 are substantially located more outward in the X-axis direction than the inner surfaces 3a2 and 3b2.

[0074] As shown in Fig. 4, the connection portions 43a and 43b have surfaces that are approximately parallel to the YZ plane and extend upward from the base portions 41a and 41b. As shown in Fig. 2, the connection portions 43a and 43b are exposed on the side surface of the core 8 in the X-axis direction at a position spaced upward from the non-mounting surface 8b of the core 8, and extend along the side surface to the mounting surface 8a of the core 8. Although detailed illustration is omitted, portions of the grooves 45a and 45b (Fig. 1) extend to the lower ends of the connection surfaces 43a and 43b, and the grooves 45a and 45b are exposed on the side surface of the core 8 in the X-axis direction.

[0075] As shown in Fig. 4, the mounting portions 44a, 44b are connected to the ends of the connecting portions 43a, 43b in the Z-axis direction and extend inward in the X-axis direction. The mounting portions 44a, 44b have surfaces parallel to the XY plane and are formed along the mounting surface 8a of the core 8 shown in Fig. 2. The mounting portions 44a, 44b are exposed to the outside of the core 8 at the mounting surface 8a and are connected to a circuit board or the like (not shown) when the inductor 1 is mounted.

[0076] The mounting portions 44a and 44b are connected to a circuit board or the like via connecting members such as solder or conductive adhesive. At this time, solder fillets can be formed on the connecting portions 43a and 43b, which can increase the mounting strength of the inductor 1 to the circuit board or the like.

[0077] Next, a method for manufacturing the inductor 1 will be described with reference to Figures 7A to 7F, etc. In the method of this embodiment, first, a conductive plate such as a metal plate (for example, a Sn-plated metal plate) is punched into a shape as shown in Figure 7A or 7C. As shown in the figures, terminals 4a and 4b connected to the frame 7 via connecting portions 43a and 43b are formed on the conductive plate after punching. On the frame 7, the terminals 4a and 4b are arranged at a predetermined interval along the X-axis direction.

[0078] Next, as shown in FIG. 7A, the coil 2 is placed between the terminals 4a and 4b. The coil 2 is placed at a predetermined distance (distances D1 to D4 shown in FIG. 6) from the terminals 4a and 4b so that a gap is formed between the main branch portions 410a and 410b (curved portions 414a and 415a) and the sub-branch portions 411a and 411b (curved portions 414b and 415b) of the terminals 4a and 4b and the outer peripheral surface 2e of the coil 2. The bottom surface 2b of the coil 2 is preferably fixed on a base (a base having the same thickness as the terminals 4a and 4b) so that the bottom surface 2b of the coil 2 is positioned substantially flush with the upper surfaces of the main branch portions 410a and 410b and the sub-branch portions 411a and 411b. To prevent the coil 2 from shifting position, the inner peripheral surface 2f of the coil 2 is preferably fixed with a positioning pin or the like.

[0079] When installing the coil 2, the outer surface 3a3 of the lead-out portion 3a of the wire 3 is fixed to the inner edge (notch 420a) of the connection portion 42a, and the connection portion 42a is positioned outward in the X-axis direction from the outer surface 3a3. Furthermore, the outer surface 3b3 of the lead-out portion 3b of the wire 3 is fixed to the inner edge of the connection portion 42b, and the connection portion 42b is positioned outward in the X-axis direction from the outer surface 3b3. The lead-out portion 3b of the wire 3 is placed on the main branch portion 410b so that the lead-out bottom portion 3b1 is in contact with the top surface of the main branch portion 410b.

[0080] Next, as shown in FIG. 7B, the connecting portions 42a, 42b are irradiated with a laser to form fusion zones 9 in the connecting portions 42a, 42b. As a result, the lead-out portions 3a, 3b are connected to the connecting portions 42a, 42b via the fusion zones 9 (see FIG. 2). In this embodiment, the lead-out portions 3a, 3b are extended in substantially the same direction along the Y-axis, so that the laser can be irradiated to the lead-out portions 3a, 3b from the same direction, facilitating laser welding. Note that the laser irradiation is preferably performed so that the fusion zones 9 do not extend inward in the X-axis direction beyond the inner surfaces 3a2, 3b2 of the lead-out portions 3a, 3b.

[0081] Next, the coil 2 with terminals 4a, 4b fixed to each end is placed inside a mold, and as shown in FIG. 7C, the first core 5 and second core 6 are combined with the coil 2 to form the temporary assembly shown in FIG. 7D. More specifically, the coil 2 and base portions 41a, 41b of the terminals 4a, 4b are placed on the top surface of the first core 5. The connection portions 43a, 43b of the terminals 4a, 4b are exposed from the first core 5 and the second core 6. Pre-molded cores (temporary molded cores) are used as the first core 5 and the second core 6. A fluid material is used as the material for the first core 5 and the second core 6, and a composite magnetic material using a thermoplastic resin or a thermosetting resin as a binder is used.

[0082] Next, the first core 5 and the second core 6 of the temporary assembly shown in Fig. 7D are compression-molded using a mold jig (upper and lower punches, etc.) to integrate them, thereby forming the core 8 (Fig. 7E). At this time, the first core 5 and the second core 6 can be easily integrated by applying heat.

[0083] Next, as shown in FIG. 7E, the frame 7 shown in FIG. 7D is cut and removed with a cutting tool so that only the connection portions 43a and 43b remain. The connection portions 43a and 43b are then fixed to the side recesses 80 formed in the core 8. More specifically, as shown in FIG. 7F, the connection portions 43a and 43b of the terminals 4a and 4b are bent substantially vertically from the state shown in FIG. 7E, and the connection portions 43a and 43b are fixed to the respective side recesses 80 on the sides of the core 8 in the X-axis direction. Furthermore, in this state, the tips of the connection portions 43a and 43b are bent substantially vertically and fixed to the ends of the respective side recesses 80 that extend to the mounting surface 8a of the core 8. This forms the mounting portions 44a and 44b of the terminals 4a and 4b on the mounting surface 8a of the core 8. In this manner, the inductor 1 of this embodiment can be obtained.

[0084] As shown in FIG. 5A, in the inductor 1 of this embodiment, the base portions 41a, 41b are located at approximately the same height as the bottom surface 2b of the coil 2. This allows the lead portions 3a, 3b of the wire 3 to be drawn to the positions of the connecting portions 42a, 42b and connected thereto without unnecessary bending. This is particularly advantageous when the coil 2 is formed from a rectangular wire or the like, which is not easy to process. This reduces damage to the lead portions 3a, 3b and allows a high-quality inductor 1 to be obtained. Furthermore, unnecessary processing (bending) of the coil 2 can be avoided, thereby reducing the number of steps.

[0085] 6, the inner edges 410a2, 410b2 of the main branches 410a, 410b and the inner edges 411a2, 411b2 of the sub-branches 411a, 411b are positioned away from the outer circumferential surface 2e of the coil 2. This prevents physical contact between the main branches 410a, 410b and the sub-branches 411a, 411b and the coil 2, ensuring sufficient voltage resistance between them. Therefore, even if the insulating coating of the coil 2 is damaged, the conductor portion of the coil 2 does not come into physical contact with the terminals 4a, 4b, preventing short circuits between them. Experiments conducted by the inventors have confirmed that the above-described positional relationship between the terminals 4a, 4b and the coil 2 ensures an impulse breakdown voltage of up to 360 V (the measurement limit of the measuring instrument). Furthermore, it was confirmed that it became possible to secure the SRF (self-resonant frequency) in the high frequency band, and that good frequency characteristics could be obtained in a wide band from 10 kHz to 5 MHz, as well as good Q values ​​in the high frequency band.

[0086] Furthermore, because the main curved portions 414a, 414b of the main branches 410a, 410b and the sub-curved portions 415a, 415b of the sub-branches 411a, 411b are curved along the outer circumferential surface 2e of the coil 2, the main branches 410a, 410b and the sub-branches 411a, 411b, as well as the connecting portions 42a, 42b, can be disposed relatively close to the outer circumferential surface 2e of the coil 2, thereby making the base portions 41a, 41b or the connecting portions 42a, 42b more compact. Furthermore, the volume of the coil 2 can be increased by the amount that the base portions 41a, 41b or the connecting portions 42a, 42b are made more compact, thereby improving the inductance characteristics of the inductor 1.

[0087] Furthermore, the center position of the imaginary circle C defined by the main curved portion 414a, the sub curved portion 415a, the main curved portion 414b, and the sub curved portion 415b substantially coincides with the center O of the inner circumference of the coil 2. This allows for a substantially constant clearance between the outer peripheral surface 2e of the coil 2 and the inner edges of the main branch portions 410a, 410b and the sub branch portions 411a, 411b. This prevents variations in inductance characteristics from occurring between individual products. This also prevents the formation of locally low-voltage-resistant regions between the base portions 41a, 41b and the coil 2, thereby improving the quality of the inductor 1.

[0088] Furthermore, the top surfaces of the base portions 41a and 41b and the bottom surface 2b of the coil 2 are located on approximately the same plane, and on this approximately same plane, the distances D1 to D4 shown in Fig. 6 are approximately equal. This makes it possible to maintain approximately constant clearances between the outer peripheral surface 2e of the coil 2 and the inner edges 410a2, 410b2, 411a2, and 411b2 of the base portions 41a and 41b, thereby further improving the quality of the inductor 1.

[0089] Second embodiment An inductor 1A according to a second embodiment of the present invention shown in Fig. 8 has the same configuration as the inductor 1 according to the first embodiment, except for the following points: In Fig. 8, components that overlap with those of the inductor 1 according to the first embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0090] As shown in FIG. 8, the inductor 1A has terminals 4aA and 4bA, which differ from the terminals 4a and 4b in the first embodiment in that the terminals 4aA and 4bA have connecting portions 42aA and 42bA. The connecting portion 42aA has a bifurcated shape and includes a housing portion 422a and a pair of protrusions 423a. The housing portion 422a is a groove with an opening at the top, cut out downward along the Z-axis direction from the upper end of the connecting portion 42aA. The lead-out portion 3a of the wire 3 can be slid into the housing portion 422a from above the connecting portion 42aA. The length of the housing portion 422a in the Z-axis direction is approximately the same as the length of the cutout portion 420a in the first embodiment. The lead-out portion 3a is positioned above and spaced apart from the bottom of the housing portion 422a, and a gap is formed between the bottom of the housing portion 422a and the lead-out bottom portion 3a1.

[0091] The pair of protrusions 423a are formed on one side and the other side of the storage portion 422a in the X-axis direction, respectively, with the storage portion 422a sandwiched therebetween. The pair of protrusions 423a makes it possible to prevent the position of the drawer portion 3a stored in the storage portion 422a from shifting inward or outward in the X-axis direction.

[0092] The connecting wire portion 42bA has a bifurcated shape and includes a housing portion 422b and a pair of protrusions 423b. The housing portion 422b is a groove with an opening at the top, cut out downward along the Z-axis direction from the upper end of the connecting wire portion 42bA. Unlike the housing portion 422a, the housing portion 422b extends to the base portion 41b (main branch portion 410b). That is, the housing portion 422b is formed not only in the connecting wire portion 42b but also at the end of the base portion 41b (main branch portion 410b) in the Y-axis direction. This configuration makes it easier to bend the pair of protrusions 423b in a direction substantially perpendicular to the base portion 41b when processing the terminal 4bA, facilitating processing of the terminal 4bA.

[0093] The lead-out portion 3b of the wire 3 can be slid into the housing portion 422b from above the connection portion 42bA and housed therein. However, the lead-out portion 3b is not housed in a portion of the housing portion 422b that extends to the end of the base portion 41b in the Y-axis direction. The length of the housing portion 422b in the Z-axis direction is shorter than the length of the lead-out portion 3b in the Z-axis direction. Therefore, the upper end of the lead-out portion 3b protrudes from above the housing portion 422b. As in the first embodiment, the lead-out portion 3b is housed in the housing portion 422b so that the lead-out bottom portion 3b1 abuts against the upper surface of the base portion 41b.

[0094] The pair of protrusions 423b are formed on one side and the other side in the X-axis direction with the accommodation portion 422b sandwiched therebetween. The pair of protrusions 423b are arranged substantially parallel to the pair of protrusions 423a.

[0095] This embodiment also provides the same effects as those of Embodiment 1. In addition, in this embodiment, the accommodating portions 422a and 422b are formed in the terminals 4aA and 4bA, and therefore the accommodating portions 422a and 422b can prevent the lead-out portions 3a and 3b from shifting in the X-axis direction and can firmly fix the lead-out portions 3a and 3b to the connecting portions 42aA and 42bA.

[0096] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

[0097] In each of the above embodiments, examples of application of the present invention to an inductor have been shown, but the present invention may also be applied to coil devices other than inductors.

[0098] In each of the above embodiments, the wire 3 is made of a rectangular wire, but it may be made of a wire other than a rectangular wire, such as a round wire or a square wire.

[0099] In the above-described embodiments, the wire 3 is wound in a circular spiral shape, but it may be wound in an elliptical spiral shape or a square spiral shape, for example.

[0100] In each of the above embodiments, the core 8 is configured with two cores, the first core 5 and the second core 6, but the core 8 of the inductor 1 may be configured with only one core. In this case, the core 8 may be formed inside a mold by powder molding, injection molding, or the like.

[0101] 4 and other figures, in the above-described embodiments, the base portions 41a, 41b are bifurcated with the groove portions 45a, 45b in between, but the base portions 41a, 41b do not have to have a bifurcated shape. That is, the groove portions 45a, 45b may be omitted from the base portions 41a, 41b. [Explanation of symbols]

[0102] 1,1A...inductor (coil device) 2...Coil 2a…Top surface 2b…Bottom surface 2c…1st drawer position 2d…Second drawer position 2e…Outer circumference 2F...inner circumference 3...Wire 3a,3b…Drawer part 3a1,3b1...Drawer bottom 3a2,3b2…inner surface 3a3,3b3…outer surface 30...Insulating coating 4a, 4b, 4aA, 4bA...Terminals 41a, 41b...Base part 410a, 410b...Main branch 411a, 411b... Sub-branch 412a, 412b...Main protrusion 413a, 413b...Sub-protruding part 414a, 414b…Main curved part 415a, 415b... Sub-curved portion 416b...recess 42a, 42b, 42aA, 42bA...Connection section 420a...Notch 421a...Bottom of notch 422a...Containment unit 423a...Protruding part 43a, 43b...Connection 44a, 44b...mounting section 45a, 45b…Groove 5...First core 6...Second core 7...Frame 8...Core 8a...Mounting surface 8b...Non-mounting side 80...Side recess 9...Melting part

Claims

1. A coil and a terminal including a connecting portion connected to the lead-out portion of the coil and a base portion positioned at substantially the same height as the bottom surface of the coil and holding the connecting portion; an element body that covers the coil together with the connection portion and the base portion, the base portion has a main branch portion and a sub-branch portion; a curved portion is formed on an inner edge of the main branch portion and the sub branch portion, the curved portion being curved along the outer circumferential surface of the coil at a position spaced from the outer circumferential surface of the coil, The connecting wire portion is continuous with the main branch portion and protrudes from the main branch portion toward the mounting surface of the element body.

2. the main branch portion has a main protrusion protruding forward of the element body, the secondary branch portion has a secondary protrusion that protrudes toward the rear of the element body, The coil device according to claim 1 , wherein one of the main projection and the sub-projection is offset in position from the other of the main projection and the sub-projection in a left-right direction perpendicular to the front-rear direction of the element body.

3. an outer edge of the main branch portion curves from a side of the element body toward a front side thereof inside the element body, an outer edge of the secondary branch portion is curved from a side of the element body toward a rear side thereof within the element body, 3. The coil device according to claim 1, wherein the radius of curvature of the outer edge of the main branch is different from the radius of curvature of the outer edge of the sub-branch.

4. The terminal has a first terminal and a second terminal, the first terminal has a first base portion; the second terminal has a second base portion; the first base portion has a first main branch portion and a first sub-branch portion; the second base portion has a second main branch portion and a second sub-branch portion; the curved portion comprises a first main curved portion formed on an inner edge of the first main branch, a first minor curved portion formed on an inner edge of the first minor branch, a second main curved portion formed on an inner edge of the second main branch, and a second minor curved portion formed on an inner edge of the second minor branch, The coil device according to any one of claims 1 to 3, wherein the center position of a virtual circle defined by the first main curved portion, the first minor curved portion, the second main curved portion, and the second minor curved portion substantially coincides with the center position of the inner circumference of the coil.

5. The top surface of the base and the bottom surface of the coil are located on approximately the same plane, 5. The coil device according to claim 4, wherein, on the substantially same plane, a distance between the first main curved portion and the outer peripheral surface of the coil, a distance between the first minor curved portion and the outer peripheral surface of the coil, a distance between the second main curved portion and the outer peripheral surface of the coil, and a distance between the second minor curved portion and the outer peripheral surface of the coil are substantially equal.

6. 6. The coil device according to claim 1, wherein the tip of the connecting wire portion is disposed at a position spaced from the upper surface of the base portion toward the mounting surface of the element body.

7. 7. The coil device according to claim 1, wherein the center position of the coil is shifted from the center of the element body to the side opposite the wire connection portion along the front-rear direction of the element body.

8. The coil device according to any one of claims 1 to 7, wherein the coil is made of a rectangular wire.

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