Coil device

Abstract

To provide a coil device with excellent inductance characteristics and high quality.SOLUTION: An inductor 1 has: a coil 2 consisting of a flat wire; a terminal 4a that has a wire joint part 42a connected with a lead-out part 3a of the coil 2; a terminal 4b that has a wire joint part 42b connected with a lead-out part 3b of the coil 2; and a core 8 that covers the coil 2 together with the wire joint part 42a and the wire joint part 42b. The wire joint part 42a is located while being biased outward in a right-and-left direction of the core 8 from a first lead-out part 3a led out in a front-and-back direction of the core 8. The wire joint part 42b is located while being biased outward in the right-and-left direction of the core 8 from a lead-out part 3b led out in the front-and-back direction of the core 8.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] As a coil device known as an inductor or the like, for example, a coil device described in Patent Document 1 is known. The coil device described in Patent Document 1 includes a body, a coil disposed inside the body, and a terminal to which a lead-out portion of the coil is connected. The terminal has a connection portion to which the lead-out portion of the coil is fixed, and a locking piece that sandwiches the lead-out portion of the coil fixed to the connection portion.

[0003] The above-described coil device is obtained by installing a coil and a terminal (a terminal in a state where the lead-out portion of the coil is connected) inside a mold, further filling a magnetic material constituting the body, and compression molding this. In the coil device described in Patent Document 1, since the lead-out portion of the coil is fixed to the connection portion and sandwiched by the locking piece, it is possible to prevent problems such as disconnection of the lead-out portion of the coil due to the pressure during compression molding.

[0004] However, in the coil device described in Patent Document 1, there is a possibility that the following problems may occur during compression molding. That is, in the coil device described in Patent Document 1, the locking piece sandwiches the lead-out portion of the coil so as to wrap around the lead-out portion of the coil fixed to the connection portion. Therefore, a part of the locking piece (and further a part of the connection portion) is arranged to protrude into the inside of the lead-out portion of the coil (the space sandwiched between the lead-out portion of the coil and the outer peripheral surface of the coil), and this protruding portion becomes an obstacle, making it difficult to fill a sufficient amount of the body inside the lead-out portion of the coil (the space sandwiched between the lead-out portion of the coil, the outer peripheral surface of the coil, and the locking piece). Therefore, it is not possible to sufficiently ensure the density of the body, and there is a possibility that the inductance characteristics of the coil device may deteriorate.

[0005] To avoid the problems mentioned above, one might consider increasing the pressure during compression molding to forcibly push the raw material into the space inside the coil's lead-out section. However, such high-pressure molding can lead to defects such as coil deformation, which can degrade the quality of the coil device. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2018-133402 [Overview of the project] [Problems that the invention aims to solve]

[0007] This invention has been made in view of the above circumstances, and its purpose is to provide a coil device that has good inductance characteristics and is of high quality. [Means for solving the problem]

[0008] To achieve the above objective, the coil device according to the present invention is A first terminal having a first connecting wire portion connected to the first lead portion of the coil, A second terminal having a second connecting wire portion connected to the second lead portion of the coil, The coil comprises a base body that covers the coil together with the first and second connecting parts, The first connecting portion is positioned along the left-right direction perpendicular to the front-rear direction of the base body, and is offset outward from the first extension portion that extends in the front-rear direction of the base body. The second connecting portion is positioned along the left-right direction perpendicular to the front-rear direction of the base body, and is offset outward from the second extension portion that extends in the front-rear direction of the base body.

[0009] In the coil device according to the present invention, the first connecting portion is positioned off-center to the outside of the first lead portion, along the left-right direction of the base material. Therefore, the first connecting portion does not significantly protrude into the inside of the first lead portion (the space sandwiched between the first lead portion and the outer surface of the coil), and the first connecting portion does not become a physical obstacle when filling the space inside the first lead portion with the base material. Thus, it is possible to fill the space inside the first lead portion with a sufficient amount of base material without being obstructed by the first connecting portion (similarly, it is possible to fill the space inside the second lead portion with a sufficient amount of base material without being obstructed by the second connecting portion), thereby ensuring sufficient density of the base material and obtaining a coil device with good inductance characteristics.

[0010] Furthermore, during compression molding, it is possible to easily fill the inner spaces of the first and second drawers with a sufficient amount of material without using high-pressure molding, thereby preventing defects such as coil deformation and enabling the production of a high-quality coil device.

[0011] Preferably, the coil is arranged inside the base body such that the thickness directions of the first and second lead portions substantially coincide with the left-right direction of the base body, the outer surface of the first lead portion in the thickness direction is mainly connected to the inner edge of the first joint portion, and the outer surface of the second lead portion in the thickness direction is mainly connected to the inner edge of the second joint portion. By using the outer surface of the first lead portion as a connection surface with the first joint portion and connecting it to the inner edge of the first joint portion, it is possible to effectively prevent the first joint portion from protruding into the space inside the first lead portion. Similarly, by using the outer surface of the second lead portion as a connection surface with the second joint portion and connecting it to the inner edge of the second joint portion, it is possible to effectively prevent the second joint portion from protruding into the space inside the second lead portion. This prevents the formation of physical obstacles that hinder the filling of the base material in the spaces inside the first and second lead portions, and allows a sufficient amount of base material to be easily filled into these spaces.

[0012] Preferably, the first extension is connected to the first connecting section via a first connecting section, and the second extension is connected to the second connecting section via a second connecting section, with the first connecting section being located off-center to the outside in the thickness direction of the first extension, and the second connecting section being located off-center to the outside in the thickness direction of the second extension. With this configuration, the first connecting section does not significantly protrude into the space inside the first extension, and the first connecting section does not pose a physical obstacle to filling the space inside the first extension with a base material. Similarly, the second connecting section does not significantly protrude into the space inside the second extension, and the second connecting section does not pose a physical obstacle to filling the space inside the second extension with a base material. Therefore, a sufficient amount of base material can be easily filled into the space inside the first extension and the space inside the second extension without being obstructed by the first and second connecting sections.

[0013] Preferably, the first and second lead sections are drawn out in substantially the same direction along the front-to-back direction of the base body. With this configuration, for example, when connecting the first and second lead sections to the first and second joint sections, respectively, by laser welding, the laser can be irradiated onto the first and second lead sections from the same direction, making laser welding easier.

[0014] Preferably, when the base body is viewed from the front-to-back direction, at least a portion of the first extension portion is located inward along the left-to-right direction of the base body from the first extension position on the outer surface of the coil from which the first extension portion is extended, and at least a portion of the second extension portion is located inward along the left-to-right direction of the base body from the second extension position on the outer surface of the coil from which the second extension portion is extended. In this configuration, an elastic force acts on the first extension portion to return it to the first extension position, so the first extension portion is fixed to the first connecting portion in a biased state. Similarly, an elastic force acts on the second extension portion to return it to the second extension position, so the second extension portion is fixed to the second connecting portion in a biased state. Therefore, the connection between the first extension portion and the first connecting portion can be maintained well, and the connection between the second extension portion and the second connecting portion can be maintained well.

[0015] Preferably, the first terminal further has a first base portion arranged substantially parallel to the bottom surface of the base body, the second terminal further has a second base portion arranged substantially parallel to the bottom surface of the base body, the first connecting portion extends upward from the first base portion, and the second connecting portion extends upward from the second base portion. With this configuration, the height of the first connecting portion can be appropriately adjusted according to the height of the first pull-out position, and the first pull-out portion can be pulled out to the position of the first connecting portion and connected thereto without unnecessarily bending the first pull-out portion. Similarly, the height of the second connecting portion can be appropriately adjusted according to the height of the second pull-out position, and the second pull-out portion can be pulled out to the position of the second connecting portion and connected thereto without unnecessarily bending the second pull-out portion.

[0016] Preferably, the inner edge of the first base portion is located outward along the left-right direction of the base body and outward from the inner surface in the thickness direction of the first extension portion, and the inner edge of the second base portion is located outward along the left-right direction of the base body and outward from the inner surface in the thickness direction of the second extension portion. With this configuration, a part of the first base portion does not significantly protrude into the space inside the first extension portion, and the first base portion does not become a physical obstacle when filling the space inside the first extension portion with the base body. Therefore, it is possible to fill the space inside the first extension portion with a sufficient amount of base body without being obstructed by the first base portion (similarly, it is possible to fill the space inside the second extension portion with a sufficient amount of base body without being obstructed by the second base portion), and a coil device with good inductance characteristics can be obtained by ensuring sufficient density of the base body.

[0017] Preferably, the position of the end of the first splice along the winding axis of the coil and the position of the end of the second splice along the winding axis of the coil are misaligned. With this configuration, when the first and second lead-out positions are misaligned along the winding axis of the coil, it becomes possible to adjust the height of the first splice to match the height of the first lead-out position, and to adjust the height of the second splice to match the height of the second lead-out position. Therefore, the first lead-out can be drawn out to the position of the first splice and connected to it without unnecessarily bending it. Similarly, the second lead-out can be drawn out to the position of the second splice and connected to it without unnecessarily bending it.

[0018] Preferably, the first lead portion is located above the second lead portion along the winding axis direction of the coil, and the length of the first connecting portion along the winding axis direction of the coil is longer than the length of the second connecting portion along the winding axis direction of the coil. With this configuration, it is possible to align the position of the first connecting portion with the height of the first lead portion, and the first lead portion can be drawn out to the position of the first connecting portion and connected to it without unnecessarily bending the first lead portion.

[0019] Preferably, a notch is formed on the inner edge of the first joint portion, cut out along the winding axis direction of the coil, and the first lead portion is fixed at a position spaced upward from the bottom of the notch in the winding axis direction. By forming a notch on the inner edge of the first joint portion for fixing the first lead portion, it is possible to miniaturize the first joint portion and effectively prevent the first joint portion from protruding into the space inside the first lead portion. Furthermore, by fixing the first lead portion to the notch, it is possible to prevent the first lead portion itself from significantly protruding toward the center of the coil, and effectively prevent the formation of a region in the space inside the first lead portion where it is difficult to fill with the material. In addition, by fixing the first lead portion at a position spaced upward from the bottom of the notch, even if the first lead position of the first lead portion fluctuates along the winding axis direction of the coil, the first lead portion will not hit the bottom of the notch, and the first lead portion can be securely fixed to the notch.

[0020] Preferably, the first lead portion is connected to the first joint portion at a position spaced upward from the upper surface of the first base portion, and the second lead portion is connected to the second joint portion while resting on the second base portion. With this configuration, the first and second lead portions can be drawn out to the positions of the first and second joint portions and connected to them without unnecessarily bending them. Furthermore, since the second lead portion is fixed to the second base portion, displacement of the second lead portion (and even the entire coil) due to applied pressure during compression molding can be effectively prevented.

[0021] Preferably, the first base portion has a first main branch portion and a first sub-branch portion. The first main branch portion has a first main protruding portion that protrudes forward of the element body, and the first sub-branch portion has a first sub-protruding portion that protrudes rearward of the element body. One of the first main protruding portion and the first sub-protruding portion is displaced in the left-right direction of the element body with respect to the other of the first main protruding portion and the first sub-protruding portion. By adopting such a configuration, due to the anchor effect exerted by the first main protruding portion and the first sub-protruding portion, it is possible to prevent the first terminal from coming off the element body and the displacement of the first base portion within the element body, particularly with respect to the left-right direction of the element body. Further, by displacing one of the first main protruding portion and the first sub-protruding portion with respect to the other along the left-right direction of the element body, it is possible to sufficiently secure the occupied area of the first main protruding portion and the first sub-protruding portion inside the element body, and the above-described effects can be effectively obtained.

[0022] Preferably, the outer edge of the first main branch portion is bent from the side of the element body toward the front inside the element body, and the outer edge of the first sub-branch portion is bent from the side of the element body toward the rear inside the element body. The radius of curvature of the outer edge of the first main branch portion is different from the radius of curvature of the outer edge of the first sub-branch portion. By adopting such a configuration, due to the anchor effect exerted by the first main branch portion and the first sub-branch portion, it is possible to prevent the first terminal from coming off the element body and the displacement of the first base portion within the element body, particularly with respect to the left-right direction of the element body. Further, by making the radius of curvature of the outer edge of the first main branch portion different from the radius of curvature of the outer edge of the first sub-branch portion, the first main branch portion or the first sub-branch portion is provided with a size sufficient to exert the above-described effect, and the above-described effect can be effectively obtained.

Brief Description of the Drawings

[0023] [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. 1. [Figure 3]FIG. 3 is a perspective view of the coil shown in FIG. 2. [Figure 4] FIG. 4 is a perspective view of the pair of terminals shown in FIG. 2. [Figure 5A] FIG. 5A is a side view showing a state when a lead portion of the coil is connected to the pair of terminals shown in FIG. 4. [Figure 5B] FIG. 5B is a perspective view showing a state when the pair of terminals and the coil shown in FIG. 5A are viewed from another angle. [Figure 6] FIG. 6 is a plan view showing a state when the coil device shown in FIG. 2 is viewed from the bottom. [Figure 7A] FIG. 7A is a diagram showing a manufacturing method of the coil device shown in FIG. 1. [Figure 7B] FIG. 7B is a diagram showing a subsequent process of FIG. 7A. [Figure 7C] FIG. 7C is a diagram showing a subsequent process of FIG. 7B. [Figure 7D] FIG. 7D is a diagram showing a subsequent process of FIG. 7C. [Figure 7E] FIG. 7E is a diagram showing a subsequent process of FIG. 7D. [Figure 7F] FIG. 7F is a diagram showing a subsequent process of FIG. 7E. [Figure 8] FIG. 8 is a perspective view of a coil device according to a second embodiment of the present invention. [[ID=3s]] [Figure 9] FIG. 9 is a perspective view of the pair of terminals shown in FIG. 8. <0000L21>

MODE FOR CARRYING OUT THE INVENTION

[0024] Hereinafter, the present invention will be described based on the embodiments shown in the drawings.

[0025] First Embodiment As shown in Figure 1, the inductor 1 according to the first embodiment of the present invention is a surface-mount type inductor and has a substantially rectangular parallelepiped shape. In Figure 1, the surface of the inductor 1 on the negative Z-axis side is the mounting surface 8a and is positioned opposite to a circuit board or the like. Hereinafter, the surface of the inductor 1 opposite to 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-back direction of the core 8, and the Z-axis direction corresponds to the up-down direction of the core 8.

[0026] As shown in Figure 2, the inductor 1 has a coil 2, a pair of terminals 4a and 4b, and a core (body) 8. Note that Figure 2 shows the inductor 1 shown in Figure 1 inverted vertically and horizontally. Therefore, the mounting surface 8a of the inductor 1 is positioned at the top of the paper, and the non-mounting surface 8b of the inductor 1 is positioned at the bottom of the paper.

[0027] In the following explanation, for ease of understanding, the top of the page (negative Z-axis direction in Figure 2) will be considered above inductor 1, and the bottom of the page (positive Z-axis direction in Figure 2) will be considered below inductor 1. Furthermore, the front of the page (positive Y-axis direction in Figure 2) will be considered in front of inductor 1, and the back of the page (negative Y-axis direction in Figure 2) will be considered behind inductor 1. In addition, the direction away from the center of core 8 or coil 2 will be considered outward, and the direction towards the center of core 8 or coil 2 will be considered inward.

[0028] The dimensions of the 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.

[0029] Core 8 is made of a mixture containing magnetic powder and binder resin, and is formed by combining the first core 5 and the second core 6 shown in Figure 7C. That is, core 8 is formed by compression molding the pre-molded first core 5 and second core 6 inside a mold to integrate them. At the joint between the first core 5 and the second core 6, the boundary between them cannot be distinguished, and they are blended together as one unit.

[0030] Core 8 (first core 5 and / or second core 6) is composed of a synthetic resin in which ferrite particles or metallic magnetic particles are dispersed. However, the material constituting core 8 is not limited to this, and may be composed of a synthetic resin that does not contain these particles. Examples of ferrite particles include Ni-Zn ferrite or Mn-Zn ferrite. Examples of metallic magnetic particles are not particularly limited, but include Fe-Ni alloy powder, Fe-Si alloy powder, Fe-Si-Cr alloy powder, Fe-Co alloy powder, Fe-Si-Al alloy powder, or amorphous iron.

[0031] The synthetic resin included in Core 8 is not particularly limited, but preferably examples include epoxy resin, phenolic resin, polyester resin, polyurethane resin, polyimide resin, or silicone resin.

[0032] As shown in Figure 3, the coil 2 is constructed as a flatwise coil. The coil 2 is formed by winding a wire 3 made of flat rectangular wire, for example, in an α-shape, and is composed of two layers along the Z-axis. By forming the coil 2 from flat 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.

[0033] The winding axis direction of coil 2 corresponds to the Z-axis direction. Wire 3 is wound such that two of the four sides constituting the outer surface of the flat rectangular wire face the inner and outer circumferences of coil 2. Alternatively, coil 2 may be formed by winding the wire such that two of the four sides constituting the outer surface of the flat rectangular wire face the inner and outer circumferences of coil 2, thereby forming an edgewise coil.

[0034] Coil 2 consists of an air-core coil, and as shown in Figure 2, coil 2 is embedded inside the core 8. Coil 2 is positioned inside the core 8 such that the thickness direction of the lead-out portions 3a and 3b substantially coincides with the X-axis direction (left-right direction of the core 8).

[0035] The materials constituting the wire 3 include, for example, good conductors of metals such as copper and copper alloys, silver, or nickel, but are not particularly limited as long as they are conductive materials. The wire 3 consists of an insulated wire, and an insulating coating 30 is formed on the surface of the wire 3. The resin constituting the insulating coating 30 is not particularly limited, but for example, polyamide-imide resin or urethane resin can be used. Alternatively, a self-fusing wire with a fusion coating on the outside of the insulating coating may be used as the wire 3. The resin constituting the fusion coating is not particularly limited, but for example, polyamide resin or epoxy resin can be used. In addition, at the positions of the lead-out portions 3a and 3b of the wire 3, the insulating coating 30 is removed in order to make electrical connections with terminals 4a and 4b.

[0036] As shown in Figure 3, the lead portion 3a of wire 3 is drawn out from a first lead position 2c located on the outer surface 2e of coil 2 in the second layer of coil 2, and extends linearly along the Y-axis. The lead portion 3b of wire 3 is drawn out from a second lead position 2d located on the outer surface 2e of coil 2 in the first layer of coil 2, and extends linearly along the Y-axis. The lead portions 3a and 3b are drawn out in the same direction (Y-axis) without twisting or bending. The first lead position 2c and the second lead position 2d are offset along the Z-axis, and the lead portions 3a and 3b are positioned offset along the Z-axis.

[0037] In the state shown in Figure 3, the extension sections 3a and 3b are extended along the Y-axis, but when connected to the connecting sections 42a and 42b, the extension sections 3a and 3b are inclined inward with respect to the Y-axis.

[0038] As shown in Figure 4, terminal 4a has a base portion 41a, a connecting portion 42a, a connection portion 43a, and a mounting portion 44a. Terminal 4b has a base portion 41b, a connecting 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 metal.

[0039] As shown in Figure 5A, the base portions 41a and 41b are located at approximately the same height as the bottom surface 2b of the coil 2 and are arranged approximately parallel to the bottom surface (non-mounting surface 8b) of the core 8 shown in Figure 2. In this embodiment, the upper surfaces of the base portions 41a and 41b and the bottom surface of the coil 2 are located on approximately the same plane. The connecting wire portions 42a and 42b are integrally formed on the base portions 41a and 41b, and the base portions 41a and 41b play a role in holding the connecting wire portions 42a and 42b.

[0040] As shown in Figure 4, the base section 41a has a main branch section 410a and a sub-branch section 411a, and the base section 41b has a main branch section 410b and a sub-branch section 411b. Both the base sections 41a and 41b have a bifurcated shape and share a common shape with some exceptions. The description of the base section 41a (main branch section 410a and sub-branch section 411a) is also applicable to the base section 41b (main branch section 410b and sub-branch section 411b), so only the particularly necessary matters will be described for the latter.

[0041] A connecting wire section 42a is connected to the end of the main branch section 410a (more specifically, the main projection section 412a, which will be described later) on the positive Y-axis side, and the main branch section 410a holds the connecting wire section 42a. The ends of the main branch section 410a and the sub-branch section 411a on the negative X-axis side are both connected to the lower end of the connecting section 43a. The main branch section 410a extends further outward in the Y-axis direction than the position of the end of the connecting section 43a on the positive Y-axis side, and the sub-branch section 411a extends further outward in the Y-axis direction than the position of the end of the connecting section 43a on the negative Y-axis side.

[0042] 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 such that the base portion 41a takes on a bifurcated shape.

[0043] The main branch 410a is located on the positive Y-axis side of the groove 45a, and the sub-branch 411a is located on the negative Y-axis side of the groove 45a. The main branch 410a and the sub-branch 411a are both bent in a roughly L-shape as a whole. Specifically, the main branch 410a extends inward in the X-axis direction from the lower end of the connecting portion 43a, then changes direction in the Y-axis direction and extends toward the positive Y-axis side. The sub-branch 411a extends inward in the X-axis direction from the lower end of the connecting portion 43a, then changes direction in the Y-axis direction and extends toward the negative Y-axis side.

[0044] As shown in Figure 6, within the core 8, the main branch 410a and the sub-branch 411a extend away from each other. Specifically, the main branch 410a extends from the side of the core 8, bending forward. The sub-branch 411a extends from the side of the core 8, bending backward. The core 8 covers the coil 2 together with the connecting section 42a and the base section 41a (main branch 410a and sub-branch 411a).

[0045] The outer edge 410a1 of the main branch 410a is smoothly curved from the side toward the front of the core 8, in accordance with the overall shape of the main branch 410a. Similarly, the outer edge 411a1 of the sub-branch 411a is smoothly curved from the side toward the rear of the core 8, 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。

[0046] By curving the outer edge 410a1 of the main branch 410a and the outer edge 411a1 of the sub-branch 411a, the anchoring effect provided by the main branch 410a and the sub-branch 411a prevents the terminal 4a from coming out of the core 8 and prevents the base portion 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 a size sufficient to achieve the above-mentioned effect, and the above-mentioned effect can be effectively obtained.

[0047] The main branch section 410a has a main projection 412a that protrudes (extends) toward the front of the core 8. The secondary branch section 411a has a secondary projection 413a that protrudes (extends) toward the rear of the core 8. The main branch section 410b has a main projection 412b that protrudes toward the front of the core 8. The secondary branch section 411b has a secondary projection 413b that protrudes toward the rear of the core 8.

[0048] The main projection 412a is formed to be thinner than the other parts of the main branch 410a, and the secondary projection 413a is formed to be thinner than the other parts of the secondary branch 411a. Furthermore, the secondary branch 411a is formed to be thinner in the X-axis direction compared to the main branch 410a.

[0049] The main projection 412a protrudes forward of the core 8 beyond the outer circumferential surface 2e of the coil 2 along the Y-axis direction. In contrast, the secondary projection 413a protrudes behind the core 8 beyond the inner circumferential surface 2f of the coil 2 along the Y-axis direction, but does not protrude behind the core 8 beyond the outer circumferential surface 2e of the coil 2. That is, the Y-axis end of the secondary projection 413a is positioned between the inner circumferential surface 2f and the outer circumferential surface 2e of the coil 2 with respect to the Y-axis direction.

[0050] One of the main protrusion 412a and the sub-protrusion 413a is offset from the other along the X-axis direction of the core 8. In this embodiment, the sub-protrusion 413a is offset further outward in the X-axis direction of the core 8 than the main protrusion 412a. That is, the inner edge of the sub-protrusion 413a is located 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 located further outward from the core 8 than the outer edge of the main protrusion 412a.

[0051] By providing the base portion 41a with a main projection 412a and a sub-projection 413a, the anchoring effect provided by the main projection 412a and the sub-projection 413a prevents the terminal 4a from coming out of the core 8 and prevents the base portion 41a from shifting position within the core 8, particularly in the left-right direction of the core 8. Furthermore, by offsetting one of the main projection 412a and the sub-projection 413a more than the other in the left-right direction of the core 8, it becomes possible to secure sufficient occupied area for the main projection 412a and the sub-projection 413a within the core 8, thereby effectively obtaining the above-mentioned effects.

[0052] As shown in Figure 4, a main curved portion 414a is formed on the inner edge 410a2 of the main branch portion 410a, and a secondary curved portion 415a is formed on the inner edge 411a2 of the secondary branch portion 411a. In addition, a main curved portion 414b is formed on the inner edge 410b2 of the main branch portion 410b, and a secondary curved portion 415b is formed on the inner edge 411b2 of the secondary branch portion 411b.

[0053] The main curved sections 414a and 414b are mainly formed in the portions of the main branched sections 410a and 410b excluding the main protruding sections 412a and 412b. The secondary curved sections 415a and 415b are mainly formed in the portions of the secondary branched sections 411a and 411b excluding the secondary protruding sections 413a and 413b.

[0054] The radius of curvature of the main curved section 414a, the radius of curvature of the secondary curved section 415a, the radius of curvature of the main curved section 414b, and the radius of curvature of the secondary curved section 415b are approximately equal. Furthermore, these radii of curvature are approximately equal to the radius of curvature of the outer circumference (outer circumference surface 2e) or inner circumference (inner circumference surface 2f) of the coil 2. Therefore, the main curved sections 414a, 414b and the secondary curved sections 415a, 415b are curved along the outer circumference surface 2e of the coil 2 at a predetermined distance from the outer circumference surface 2e of the coil 2.

[0055] As shown in Figure 6, the inner edge 410a2 of the main branch 410a faces the outer surface 2e of the coil 2 at a predetermined distance D1. The inner edge 411a2 of the sub-branch 411a faces the outer surface 2e of the coil 2 at a predetermined distance D2. The inner edge 410b2 of the main branch 410b faces the outer surface 2e of the coil 2 at a predetermined distance D3. The inner edge 411b2 of the sub-branch 411b faces the outer surface 2e of the coil 2 at a predetermined distance D4. In other words, the main branch 410a, 410b and the sub-branch 411a, 411b do not come into contact with the coil 2, but are arranged around the outer surface 2e of the coil 2, surrounding it. In this embodiment, on a virtual plane parallel to the bottom surface 2b of the coil 2 and the upper surfaces of the base portions 41a, 41b, distances D1, D2, D3, and D4 are approximately equal.

[0056] The center position of the virtual circle C defined by the main curved section 414a, the secondary curved section 415a, the main curved section 414b, and the secondary curved section 415b substantially coincides with the center position of the inner circumference (inner surface 2f) or outer circumference (outer surface 2e) of the coil 2. In other words, the virtual circle C and the virtual circle defined by the inner circumference (inner surface 2f) or outer circumference (outer surface 2e) of the coil 2 are arranged concentrically.

[0057] As shown in Figure 5A, the inner edge 410a2 of the main branch 410a is located outward in the X-axis direction from the inner surface 3a2 of the extension 3a. Although detailed illustration is omitted, the inner edge 411a2 of the sub-branch 411a (Figure 4) is similarly located outward in the X-axis direction from the inner surface 3a2 of the extension 3a. In other words, neither the main branch 410a nor the sub-branch 411a protrudes inward from the inner surface 3a2 of the extension 3a.

[0058] Furthermore, the inner edge 410b2 of the main branch 410b is located outward in the X-axis direction from the inner surface 3b2 of the pull-out section 3b. Although detailed illustrations are omitted, the inner edge 411b2 of the sub-branch 411b (Figure 4) is similarly located outward in the X-axis direction from the inner surface 3b2 of the pull-out section 3b. In other words, neither the main branch 410b nor the sub-branch 411b protrudes inward from the inner surface 3b2 of the pull-out section 3b.

[0059] Of the main branch section 410a and the main branch section 410b, the bottom portion 3b1 of the lead portion 3b, which is drawn out from below the coil 2 (second lead position 2d), is placed on the upper surface of the main branch section 410b. As a result, the lead portion 3b is fixed to the main branch section 410b, and during the manufacturing of the inductor 1 (during the compression molding of the first core 5 and the second core 6 shown in Figure 7C), displacement of the lead portion 3b (and even the entire coil 2) due to applied pressure can be effectively prevented. Note that the lead portion 3a of the wire 3 is drawn out from above the coil 2 (first lead position 2c), and is therefore not placed on the upper surface of the main branch section 410a, but is positioned at a location spaced above the upper surface of the main branch section 410a.

[0060] As shown in Figure 4, of the two main branch sections 410a and 410b, the recess 416b is formed only in the main branch section 410b. The recess 416b is formed on the inner edge 410b2 of the main branch section 410b and is located in a different position from the main curved section 414b (forward of the main curved section 414b). The recess 416b is provided to adjust (narrow) the width in the X-axis direction of the main projection 412b and further to the connecting wire section 42b.

[0061] The connecting sections 42a and 42b have a flat plate shape substantially parallel to the XZ plane and are arranged substantially perpendicular to the lead-out sections 3a and 3b (see Figure 5B). As shown in Figure 2, the connecting sections 42a and 42b are located inside the core 8. The lead-out sections 3a and 3b of the wire 3 are connected to the connecting sections 42a and 42b. More specifically, the lead-out section 3a is connected to the connecting section 42a at a position spaced above the upper surface of the base section 41a. The lead-out section 3b is connected to the connecting section 42b while resting on the base section 41b. In this embodiment, since the lead-out sections 3a and 3b are drawn out in substantially the same direction (positive Y-axis direction), the connecting sections 42a and 42b are located on the positive Y-axis side of the coil 2 from which the lead-out sections 3a and 3b are drawn.

[0062] As shown in Figure 4, the connecting sections 42a and 42b extend along the Z-axis direction and rise upward from the Y-axis positive end of the main branch sections 410a and 410b. The connecting sections 42a and 42b are positioned approximately perpendicular to the main branch sections 410a and 410b. The rising positions of the connecting sections 42a and 42b are located in front of the Y-axis positive end of the connecting section 43a and 43b. As shown in Figure 2, the Y-axis positive end of the base section 41a and 41b is located further out in the Y-axis direction than the Y-axis positive end of the coil 2, so the rising positions of the connecting sections 42a and 42b are located further out in the Y-axis direction than the Y-axis positive end of the coil 2.

[0063] As shown in Figure 5A, the Z-axis length of the splice section 42a is longer than the Z-axis length of the splice section 42b. The Z-axis length of the splice section 42a is greater than the Z-axis length of the wire 3, and the upper end of the splice section 42a is positioned to correspond to the second layer (first withdrawal position 2c) of the coil 2. Therefore, when the withdrawal section 3a is withdrawn from the first withdrawal position 2c, it can be withdrawn to the position of the splice section 42a and connected to it without unnecessarily bending the withdrawal section 3a.

[0064] The length of the splice section 42b in the Z-axis direction is shorter than the length of the wire 3 in the Z-axis direction, and the upper end of the splice section 42b is positioned at the location corresponding to the first layer (second lead-out position 2d) of the coil 2. Therefore, the position of the upper end of the splice section 42a and the position of the upper end of the splice section 42b are misaligned along the Z-axis direction.

[0065] In this way, the positions (heights) of the connecting sections 42a and 42b are adjusted to match the positions (heights) of the pull-out positions 2c and 2d. Therefore, the pull-out sections 3a and 3b can be pulled out to the positions of the connecting sections 42a and 42b and connected to them without unnecessarily bending them.

[0066] As shown in Figure 6, the center O of the coil 2 is offset along the Y-axis direction from the center of the core 8 to the opposite side of the connecting sections 42a and 42b (towards the rear of the core 8). This configuration allows for sufficient volume of the core 8 to be secured in front of the core 8. Therefore, the connecting sections 42a and 42b and the connected lead sections 3a and 3b can be covered with a sufficient amount of core 8 and protected by the core 8. In addition, sufficient space is formed in front of the core 8 to place the connecting sections 42a and 42b, so there is no need to extend the core 8 forward to secure this space, and the inductor 1 can be made smaller.

[0067] Furthermore, it becomes possible to position the outer surface 2e of the coil 2 at a position sufficiently far from the side surface of the core 8 on the positive Y-axis side, 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 Y-axis side, and preventing cracks from occurring on the side surface of the core 8 on the positive Y-axis side.

[0068] As shown in Figure 5A, when the core 8 is viewed from the front, at least a portion of the pull-out portion 3a is located inward in the X-axis direction from the first pull-out position 2c on the outer circumferential surface 2e of the coil 2 from which the pull-out portion 3a is pulled. Also, at least a portion of the pull-out portion 3b is located inward in the X-axis direction from the second pull-out position 2d on the outer circumferential surface 2e of the coil 2 from which the pull-out portion 3b is pulled. With this configuration, an elastic force acts on the pull-out portion 3a that tries to return it to the first pull-out position 2c (outward in the X-axis direction), so the pull-out portion 3a is fixed to the connecting portion 42a in a biased state. Similarly, an elastic force acts on the pull-out portion 3b that tries to return it to the second pull-out position 2d (outward in the X-axis direction), so the pull-out portion 3b is fixed to the connecting portion 42b in a biased state. Therefore, the connection between the pull-out portion 3a and the connecting portion 42a can be maintained well, and the connection between the pull-out portion 3b and the connecting portion 42b can also be maintained well.

[0069] Of the connecting portion 42a and connecting portion 42b, a notch 420a is formed on the inner edge of connecting portion 42a, cut out along the Z-axis direction. The notch 420a is cut downward from the upper end of connecting portion 42a to a predetermined depth. The lead-out portion 3a of the wire 3 can be fixed to the notch 420a.

[0070] The length of the notch 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 Figure 5A, the bottom 3a1 of the lead-out portion 3a is fixed at a position spaced upward from the bottom 421a of the notch and does not come into contact with the bottom 421a. Therefore, when the lead-out portion 3a is fixed to the notch 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 notch 420a.

[0071] In this way, by fixing the extension portion 3a at a position spaced upward from the notch bottom portion 421a, even if the first extension position 2c of the extension portion 3a fluctuates along the Z-axis direction, the extension portion 3a will not come into contact with the notch bottom portion 421a, and the extension portion 3a can be securely fixed to the notch portion 420a. Furthermore, when connecting the extension portion 3a to the connecting portion 42a, the extension portion 3a can be fixed to the notch portion 420a in a straight-out state without bending the extension portion 3a.

[0072] Furthermore, the upper end of the lead-out section 3b also protrudes above the upper end of the connecting section 42b, similar to the upper end of the lead-out section 3a. This is because, due to the miniaturization of the connecting section 42b, the length of the connecting section 42b in the Z-axis direction is smaller than the length of the wire 3 in the Z-axis direction.

[0073] The inner edge of the connecting section 42a is connected to the outer surface 3a3 of the pull-out section 3a (more specifically, a part or most of the outer surface 3a3), and the inner edge of the connecting section 42b is connected to the outer surface 3b3 of the pull-out section 3b (more specifically, a part or most of the outer surface 3b3). The inner surface 3a2 of the pull-out section 3a is not fixed to the connecting section 42a, and the inner surface 3b2 of the pull-out section 3b is not fixed to the connecting section 42b.

[0074] With respect to the X-axis direction, the outer surface 3a3 of the lead-out portion 3a is located inward from the outer surface 2e of the coil 2 at the first lead-out position 2c. Therefore, the inner edge of the connecting portion 42a is located between the outer surface 3a3 of the lead-out portion 3a and the outer surface 2e of the coil 2 at the first lead-out position 2c, with respect to the X-axis direction. Also, with respect to the X-axis direction, the outer surface 3b3 of the lead-out portion 3b is located inward from the outer surface 2e of the coil 2 at the second lead-out position 2d. Therefore, the inner edge of the connecting portion 42b is located between the outer surface 3b3 of the lead-out portion 3b and the outer surface 2e of the coil 2 at the second lead-out position 2d, with respect to the X-axis direction.

[0075] In this embodiment, the connecting portion 42a is positioned further outward in the X-axis direction than the pull-out portion 3a which is pulled forward from the core 8. Similarly, the connecting portion 42b is positioned further outward in the X-axis direction than the pull-out portion 3b which is pulled forward from the core 8. More specifically, the inner edge of the connecting portion 42a is positioned further outward in the X-axis direction than the inner surface 3a2 of the pull-out portion 3a. Furthermore, at the location of the notch 420a, the inner edge of the connecting portion 42a is positioned further outward in the X-axis direction than the outer surface 3a3 of the pull-out portion 3a. Also, the inner edge of the connecting portion 42b is positioned further outward in the X-axis direction than the inner surface 3b2 and outer surface 3b3 of the pull-out portion 3a. In other words, the connecting sections 42a and 42b do not protrude inward in the X-axis direction beyond the inner surfaces 3a2 and 3b2 of the leading sections 3a and 3b, and the entire connecting sections 42a and 42b are positioned outward in the X-axis direction beyond the inner surfaces 3a2 and 3b2.

[0076] As shown in Figure 2, the lead-out sections 3a and 3b are connected to the joint sections 42a and 42b via the molten section 9. The molten section 9 consists of a weld ball formed when the terminals 4a and 4b (joint sections 42a and 42b) are irradiated with a laser. However, the molten section 9 may be a connecting member made of solder, conductive adhesive, etc. In the joint section 42a, the molten section 9 is located outward in the X-axis direction from the inner surface 3a2 of the lead-out section 3a. In the joint section 42b, the molten section 9 is located outward in the X-axis direction from the inner surface 3b2 of the lead-out section 3b. That is, the molten section 9 does not substantially protrude inward in the X-axis direction from the inner surfaces 3a2 and 3b2 of the lead-out sections 3a and 3b (it is not formed there), and the entire molten section 9 is substantially located outward in the X-axis direction from the inner surfaces 3a2 and 3b2.

[0077] As shown in Figure 4, the connecting portions 43a and 43b have surfaces substantially parallel to the YZ plane and extend upward from the base portions 41a and 41b. As shown in Figure 2, the connecting portions 43a and 43b are exposed on the X-axis side surface of the core 8 at a position spaced upward from the non-mounting surface 8b of the core 8, and extend along this side surface to the mounting surface 8a of the core 8. Although detailed illustration is omitted, a portion of the grooves 45a and 45b (Figure 1) extends to the lower ends of the connecting surfaces 43a and 43b, and the grooves 45a and 45b are exposed on the X-axis side surface of the core 8.

[0078] As shown in Figure 4, the mounting portions 44a and 44b are connected to the Z-axis ends of the connecting portions 43a and 43b and extend inward in the X-axis direction. The mounting portions 44a and 44b have surfaces parallel to the XY plane and are formed along the mounting surface 8a of the core 8 shown in Figure 2. The mounting portions 44a and 44b are exposed to the outside of the core 8 on the mounting surface 8a and are connected to a circuit board or the like (not shown) when the inductor 1 is mounted.

[0079] The mounting sections 44a and 44b are connected to a circuit board or the like via connecting materials such as solder or conductive adhesive. At that time, solder fillets can be formed on the connecting sections 43a and 43b, thereby increasing the mounting strength of the inductor 1 to the circuit board or the like.

[0080] Next, the 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 out into the shape shown in Figure 7A or Figure 7C. As shown in the same figure, terminals 4a and 4b are formed on the punched conductive plate and connected to the frame 7 via connecting portions 43a and 43b. In the frame 7, the terminals 4a and 4b are arranged at predetermined intervals along the X-axis direction.

[0081] Next, as shown in Figure 7A, the coil 2 is installed between terminals 4a and 4b. At this time, the coil 2 is installed at a predetermined distance (distances D1 to D4 shown in Figure 6) from 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 terminals 4a and 4b and the outer surface 2e of the coil 2. Furthermore, it is preferable to fix the bottom surface 2b of the coil 2 on a base (however, the base having the same thickness as terminals 4a and 4b) so that the bottom surface 2b of the coil 2 and the top surfaces of the main branch portions 410a and 410b and the sub-branch portions 411a and 411b are arranged on substantially the same plane. In addition, it is preferable to fix the inner surface 2f of the coil 2 with positioning pins or the like to prevent the coil 2 from shifting position.

[0082] When installing coil 2, the outer surface 3a3 of the wire lead portion 3a is fixed to the inner edge (notch 420a) of the connecting portion 42a, and the connecting portion 42a is positioned outside the outer surface 3a3 in the X-axis direction. Also, the outer surface 3b3 of the wire lead portion 3b is fixed to the inner edge of the connecting portion 42b, and the connecting portion 42b is positioned outside the outer surface 3b3 in the X-axis direction. The wire lead portion 3b is placed on the main branch portion 410b so that the lead bottom portion 3b1 is in contact with the upper surface of the main branch portion 410b.

[0083] Next, as shown in Figure 7B, a laser is irradiated onto the joint sections 42a and 42b to form a molten section 9 on the joint sections 42a and 42b. As a result, the drawn-out sections 3a and 3b are connected to the joint sections 42a and 42b via the molten section 9 (see Figure 2). In this embodiment, since the drawn-out sections 3a and 3b are drawn out in substantially the same direction along the Y-axis, laser irradiation can be performed on the drawn-out sections 3a and 3b from the same direction, making laser welding easy. It is preferable that the laser irradiation is performed so that the molten section 9 does not protrude inward in the X-axis direction beyond the inner surfaces 3a2 and 3b2 of the drawn-out sections 3a and 3b.

[0084] Next, a coil 2 with terminals 4a and 4b fixed to each end is placed inside the mold, and as shown in Figure 7C, the first core 5 and the second core 6 are combined with the coil 2 to form the temporary assembly shown in Figure 7D. More specifically, the base portions 41a and 41b of the coil 2 and terminals 4a and 4b are placed on the upper surface of the first core 5. The connection portions 43a and 43b of terminals 4a and 4b are left exposed from the first core 5 and the second core 6. The first core 5 and the second core 6 are pre-molded cores (temporarily molded cores). The materials used to make up the first core 5 and the second core 6 are fluid materials, and composite magnetic materials with thermoplastic resin or thermosetting resin as a binder are used.

[0085] Next, using a mold jig (such as upper and lower punches), the first core 5 and the second core 6 of the temporary assembly shown in Figure 7D are compression molded and integrated to form the core 8 (Figure 7E). At this time, the first core 5 and the second core 6 can be easily integrated by applying heat.

[0086] Next, as shown in Figure 7E, the frame 7 shown in Figure 7D is cut and removed with a cutting tool so that only the connection portions 43a and 43b remain. Then, the connection portions 43a and 43b are fixed to the lateral recesses 80 formed in the core 8. More specifically, as shown in Figure 7F, the connection portions 43a and 43b of terminals 4a and 4b are bent approximately vertically from the state shown in Figure 7E, and the connection portions 43a and 43b are fixed to the respective lateral recesses 80 on the X-axis side of the core 8. In that state, the tips of the connection portions 43a and 43b are bent approximately vertically and fixed to the ends of the respective lateral recesses 80 that extend to the mounting surface 8a of the core 8. As a result, the mounting portions 44a and 44b of terminals 4a and 4b are formed on the mounting surface 8a of the core 8. In this way, the inductor 1 of this embodiment can be obtained.

[0087] As shown in Figure 5A, in the inductor 1 of this embodiment, the connecting portions 42a and 42b are positioned off-center to the outside of the lead portions 3a and 3b along the X-axis. Therefore, the connecting portions 42a and 42b do not significantly protrude into the inside of the lead portions 3a and 3b (the space 10 sandwiched between the lead portion 3a and the outer surface 2e of the coil 2 as shown in Figure 5A / the space 10 sandwiched between the lead portion 3b and the outer surface 2e of the coil 2), and the connecting portions 42a and 42b do not become a physical obstacle that hinders filling the space 10 inside the lead portions 3a and 3b with core 8. Therefore, it is possible to fill the space 10 inside the lead portions 3a and 3b with a sufficient amount of core 8 without being hindered by the connecting portions 42a and 42b, thereby ensuring sufficient density of core 8 and obtaining an inductor 1 with good inductance characteristics.

[0088] Furthermore, during compression molding, it is possible to easily fill the inner space 10 of the drawout sections 3a and 3b with a sufficient amount of core 8 without using high-pressure molding, thereby preventing defects such as deformation of the coil 2 and obtaining a high-quality inductor 1.

[0089] Furthermore, by utilizing the outer surfaces 3a3 and 3b3 of the extension sections 3a and 3b as connection surfaces with the connecting sections 42a and 42b, and connecting these to the inner edges of the connecting sections 42a and 42b, it is possible to effectively prevent the connecting sections 42a and 42b from protruding into the inner space 10 of the extension sections 3a and 3b. This prevents the formation of physical obstacles that hinder the filling of the core 8 into the inner space 10 of the extension sections 3a and 3b, and allows a sufficient amount of core 8 to be easily filled into the space.

[0090] Furthermore, as shown in Figure 2, since the molten portion 9 is unevenly distributed to the outside in the X-axis direction of the drawout portions 3a and 3b, the molten portion 9 does not significantly protrude into the space 10 inside the drawout portions 3a and 3b, and the molten portion 9 does not pose a physical obstacle to filling the space 10 inside the drawout portions 3a and 3b with core 8. Therefore, a sufficient amount of core 8 can be easily filled into the space 10 inside the drawout portions 3a and 3b without being hindered by the molten portion 9.

[0091] Furthermore, as shown in Figure 6, the inner edges 410a2 and 411a2 of the base portion 41a (main branch portion 410a and sub-branch portion 411a) are located outward in the X-axis direction from the inner surface 3a2 of the drawer portion 3a. Also, the inner edges 410b2 and 411b2 of the base portion 41b (main branch portion 410b and sub-branch portion 411b) are located outward in the X-axis direction from the inner surface 3b2 of the drawer portion 3b. Therefore, no part of the base portion 41a protrudes significantly into the space 10 inside the drawer portions 3a and 3b, and the base portions 41a and 41b do not become a physical obstacle that hinders filling the space 10 inside the drawer portions 3a and 3b with the core 8. Therefore, it is possible to fill the inner space 10 of the lead-out sections 3a and 3b with a sufficient amount of core 8 without being obstructed by the base sections 41a and 41b, thereby ensuring sufficient density of the core 8 and obtaining an inductor 1 with good inductance characteristics.

[0092] Furthermore, as shown in Figure 5A, a notch 420a is formed on the inner edge of the connecting portion 42a, and the lead portion 3a is fixed at a position spaced upward from the bottom 421a of the notch 420a. By forming a notch 420a on the inner edge of the connecting portion 42a for fixing the lead portion 3a, it is possible to miniaturize the connecting portion 42a and effectively prevent the connecting portion 42a from protruding into the space 10 inside the lead portion 3a. In addition, by fixing the lead portion 3a to the notch 420a, it is possible to prevent the lead portion 3a itself from significantly protruding toward the center of the coil 2, and effectively prevent the formation of a region in the space 10 inside the lead portion 3a where filling with the core 8 is difficult.

[0093] Second Embodiment The inductor 1A according to the second embodiment of the present invention, shown in Figure 8, has the same configuration as the inductor 1 of the first embodiment, except for the points described below. In Figure 8, the same reference numerals are used for components that overlap with the inductor 1 of the first embodiment, and their detailed descriptions are omitted.

[0094] As shown in Figure 8, inductor 1A has terminals 4aA and 4bA, and terminals 4aA and 4bA have base portions 41aA and 41bA, which is different from terminals 4a and 4b in the first embodiment. As shown in Figure 9, unlike base portions 41a and 41b in the first embodiment (Figure 4), the base portions 41aA and 41bA do not have a bifurcated shape, but are substantially rectangular in shape.

[0095] As shown in Figure 8, in this embodiment, each end of the bottom surface 2b of the coil 2 in the X-axis direction rests on the upper surface of the base portions 41aA, 41bA, and the coil 2 is supported by the base portions 41aA, 41bA. As mentioned above, the coil 2 is positioned inside the core 8 such that its center is offset rearward from the center of the core 8. Therefore, in order to support this rearward-off coil 2, the base portions 41aA, 41bA protrude relatively far rearward (outward) in the Y-axis direction from the connecting portions 43a, 43b, as shown in Figure 9.

[0096] In this embodiment, the same effects as in the first embodiment can be obtained. In addition, in this embodiment, when manufacturing the inductor 1, it is possible to install the coil 2 together with the terminals 4aA and 4bA inside the mold with the bottom surface of the coil 2 placed on the base parts 41aA and 41bA. By placing the bottom surface of the coil 2 on the base parts 41aA and 41bA in this way, the bottom surface of the coil 2 is supported by the base parts 41aA and 41bA, so even if a pressing force is applied to the coil 2 during compression molding, the coil 2 is less likely to shift position in the Z-axis direction, and the position of the bottom surface of the coil 2 is fixed to the position of the upper surface of the base parts 41aA and 41bA. Therefore, it is possible to set the position of the coil 2 in a predetermined position inside the core 8, preventing variations in inductance characteristics etc. from product to product due to variations in the position of the coil 2, and a highly reliable inductor 1A can be obtained.

[0097] It should be noted that the present invention is not limited to the embodiments described above, and can be modified in various ways within the scope of the present invention.

[0098] Although the above embodiments illustrate examples of applying the present invention to inductors, the present invention may also be applied to coil devices other than inductors.

[0099] In each of the embodiments described above, the wire 3 was composed of a flat rectangular wire, but it may be composed of a wire other than a flat rectangular wire, such as a round wire or a square wire.

[0100] In the embodiments described above, the winding shape of the wire 3 was a circular spiral, but it may also be an elliptical spiral, a square spiral, or the like.

[0101] In each of the embodiments described above, the core 8 is composed of two cores, the first core 5 and the second core 6. However, the core 8 of the inductor 1 may be composed of only one core. In this case, the core 8 may be formed inside the mold by powder compaction molding or injection molding. [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, 41aA, 41bA... Base section 410a, 410b... Main branch section 411a, 411b... Sub-branch section 412a, 412b...Main protrusion 413a, 413b...Sub-protruding part 414a, 414b…Main curved part 415a, 415b... Sub-curved sections 416b…recess 42a, 42b…Connection section 420a... Notch 421a...Bottom of the notch 43a, 43b… Connection part 44a, 44b…Implementation section 45a, 45b…Groove 5…First Core 6…Second Core 7...frames 8...core 8a…Implementation side 8b... Anti-implementation side 80... Lateral recess 9…Molten part

Claims

1. A first terminal having a plate-shaped first connecting wire portion connected to the first lead portion of the coil, A second terminal having a plate-shaped second connecting wire portion connected to the second lead portion of the coil, The coil comprises a base body that covers the coil together with the first and second connecting parts, The first connecting portion is positioned along the left-right direction perpendicular to the front-rear direction of the base body, and is offset outward from the first extension portion that extends in the front-rear direction of the base body. The second connecting portion is positioned along the left-right direction perpendicular to the front-rear direction of the base body, and is offset outward from the second extension portion that extends in the front-rear direction of the base body. The coil is arranged inside the base body such that the thickness directions of the first and second lead-out portions substantially coincide with the left-right direction of the base body. The outer surface of the first extension portion in the thickness direction is mainly connected to the inner edge of the first joint portion. The outer surface of the second extension portion in the thickness direction is mainly connected to the inner edge of the second connecting portion, forming a coil device.

2. A first terminal having a plate-shaped first connecting wire portion connected to the first lead portion of the coil, A second terminal having a plate-shaped second connecting wire portion connected to the second lead portion of the coil, The coil comprises a base body that covers the coil together with the first and second connecting parts, The first connecting portion is positioned along the left-right direction perpendicular to the front-rear direction of the base body, and is offset outward from the first extension portion that extends in the front-rear direction of the base body. The second connecting portion is positioned along the left-right direction perpendicular to the front-rear direction of the base body, and is offset outward from the second extension portion that extends in the front-rear direction of the base body. The first lead-out section is connected to the first connecting section by the first connecting section. The second lead-out section is connected to the second connecting section by the second connection section. The first connecting portion is located off-center to the outer side in the thickness direction of the first drawer portion. The second connecting portion is a coil device located off-center to the outside in the thickness direction of the second drawer portion.

3. A first terminal having a plate-shaped first connecting wire portion connected to the first lead portion of the coil, A second terminal having a plate-shaped second connecting wire portion connected to the second lead portion of the coil, The coil comprises a base body that covers the coil together with the first and second connecting parts, The first connecting portion is positioned along the left-right direction perpendicular to the front-rear direction of the base body, and is offset outward from the first extension portion that extends in the front-rear direction of the base body. The second connecting portion is positioned along the left-right direction perpendicular to the front-rear direction of the base body, and is offset outward from the second extension portion that extends in the front-rear direction of the base body. A coil device in which, when the main body is viewed from the front-to-back direction, at least a portion of the first pull-out portion is located inward along the left-to-right direction of the main body from a first pull-out position on the outer surface of the coil from which the first pull-out portion is pulled, and at least a portion of the second pull-out portion is located inward along the second pull-out position on the outer surface of the coil from which the second pull-out portion is pulled.

4. A first terminal having a plate-shaped first connecting wire portion connected to the first lead portion of the coil, A second terminal having a plate-shaped second connecting wire portion connected to the second lead portion of the coil, The coil comprises a base body that covers the coil together with the first and second connecting parts, The first connecting portion is positioned along the left-right direction perpendicular to the front-rear direction of the base body, and is offset outward from the first extension portion that extends in the front-rear direction of the base body. The second connecting portion is positioned along the left-right direction perpendicular to the front-rear direction of the base body, and is offset outward from the second extension portion that extends in the front-rear direction of the base body. The first terminal further has a first base portion that is arranged substantially parallel to the bottom surface of the base body, The second terminal further has a second base portion that is arranged substantially parallel to the bottom surface of the base body, The first connecting section extends upward from the first base section. The second connecting section is a coil device that extends upward from the second base section.

5. The inner edge of the first base portion is located outward from the inner surface in the thickness direction of the first drawer portion, along the left-right direction of the base body. The coil device according to claim 4, wherein the inner edge of the second base portion is located outward from the inner surface in the thickness direction of the second drawer portion, along the left-right direction of the base body.

6. The coil device according to claim 4 or 5, wherein the position of the end of the first connecting wire portion along the winding axis direction of the coil and the position of the end of the second connecting wire portion along the winding axis direction of the coil are misaligned.

7. The first lead portion is located above the second lead portion along the winding axis of the coil, The coil device according to any one of claims 4 to 6, wherein the length of the first connecting wire portion along the winding axis direction of the coil is longer than the length of the second connecting wire portion along the winding axis direction of the coil.

8. A notch is formed on the inner edge of the first connecting portion, which is cut out along the winding axis of the coil. The coil device according to any one of claims 4 to 7, wherein the first lead portion is fixed at a position spaced upward from the bottom of the notch in the winding axis direction.

9. The first extension is connected to the first connecting wire at a position spaced upward from the upper surface of the first base, The coil device according to any one of claims 4 to 8, wherein the second lead-out portion is placed on the second base portion and connected to the second connecting portion.

10. The first base portion has a first main branch and a first sub-branch, The first main branch portion has a first main projection that protrudes toward the front of the base body, The first sub-branch portion has a first sub-projection portion that protrudes toward the rear of the base body, The coil device according to any one of claims 4 to 9, wherein one of the first main projection and the first sub-projection is offset in the left-right direction of the base body more than the other of the first main projection and the first sub-projection.

11. The outer edge of the first main branch is bent from the side toward the front of the body within the body. The outer edge of the first sub-branch portion is bent from the side toward the rear within the base body. The coil device according to claim 10, wherein the radius of curvature of the outer edge of the first main branch is different from the radius of curvature of the outer edge of the first sub-branch.

12. The coil device according to any one of claims 1 to 11, wherein the first and second drawers are drawn out in substantially the same direction along the front-to-back direction of the base body.

13. A first terminal having a plate-shaped first connecting wire portion connected to the first lead portion of the coil, A second terminal having a plate-shaped second connecting wire portion connected to the second lead portion of the coil, The coil comprises a base body that covers the coil together with the first and second connecting parts, The first and second lead-out portions of the coil are each extended forward of the base body. When viewed from the front-to-back direction of the main body, the first connecting portion is located outside the left-to-right direction perpendicular to the front-to-back direction compared to the first extending portion, and the first extending portion and the first connecting portion are in contact in the left-to-right direction. When viewed from the front-to-back direction of the main body, the second connecting wire portion is located outside the second connecting wire portion in the left-to-right direction perpendicular to the front-to-back direction, and the second connecting wire portion and the second connecting wire portion are in contact in the left-to-right direction. The first connecting portion has a first main surface perpendicular to the front-rear direction and a first side surface perpendicular to the first main surface and in contact with the first lead portion in the left-right direction. The second connecting portion is a coil device having a second main surface perpendicular to the front-rear direction and a second side surface perpendicular to the second main surface and in contact with the second lead portion in the left-right direction.

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