Coil component

Abstract

Provided is a coil component of an integrated core, the coil component making it easy to bring a wire closer to one end side in an axial direction of a winding core part, when starting to wind the wire around the winding core part and winding the wire, even if members disposed at a predetermined interval with respect to the winding core part exist in the integrated core.　In a core (2), a gap (11) for dividing a part of a loop of magnetic flux passing through a winding core part (3), a first flange part (5), a second flange part (6), and a top plate part (7) is provided at a position offset toward the second flange part (6) side in the top plate part (7). At least a part of the peripheral surface of the winding core part (3), for example, a top surface (13), is provided with a sloped surface (19) that is inclined with respect to the axial direction, so that the length in the circumferential direction of the winding core part (3) becomes shorter with decreasing distance toward the first flange part (5).

Description

Coil parts

[0001] The present invention relates to a coil component including a core having a winding core portion around which wire is wound, a first flange portion and a second flange portion provided at each end of the winding core portion, and a top plate portion arranged to connect the first flange portion and the second flange portion, and in particular to the structure of the core.

[0002] For example, Japanese Patent Laid-Open Publication No. 2003-163119 (Patent Document 1) describes a coil component having a core in which a winding core around which a wire is wound, first and second flanges extending in one direction from each end of the winding core, and bridges extending from the first and second flanges are integrated. The bridges are disposed at a predetermined distance from the winding core. The bridges have a gap in their longitudinal centers, forming a predetermined distance.

[0003] With the core described in Patent Document 1, there is a concern that the presence of the bridge portions, which are arranged at a predetermined distance from the winding core, may hinder the winding of the wire when the wire is wound around the winding core. In relation to this, paragraph 0020 of Patent Document 1 states, "By forming the tip faces of the bridge portions 1c to face each other at a predetermined distance L in this way, a gap 7 is formed between the tip faces of the facing bridge portions 1c, and by utilizing this gap 7, the winding of the conductor wire 3 around the body portion 1b can be easily performed."

[0004] Japanese Patent Application Laid-Open No. 2003-163119

[0005] When starting to wind the wire around the winding core, it is preferable to move the wire toward one end in the axial direction of the winding core. Also, while winding the wire around the winding core, it is preferable to easily apply a force to move the wire toward one end in the axial direction of the winding core. This is because the limited axial dimension of the winding core can be effectively used to arrange the wire around the winding core.

[0006] However, in the configuration described in Patent Document 1, a gap is provided in the bridge portion that forms a predetermined distance in the center of the bridge portion in the longitudinal direction. Therefore, it is conceivable that when starting to wind the wire around the winding core portion, it is not easy to move the wire toward one end in the axial direction of the winding core portion, or to apply a force to move the wire toward one end in the axial direction of the winding core portion while winding the wire around the winding core portion.

[0007] Therefore, an object of the present invention is to provide a coil component in which, even if there is a component in an integrated core that is positioned at a predetermined distance from the winding core and arranged along the axial direction of the winding core, when starting to wind the wire around the winding core, it is easy to move the wire toward one end in the axial direction of the winding core, or to apply a force to move the wire toward one end in the axial direction of the winding core while winding the wire around the winding core.

[0008] The coil component according to the present invention includes a core made of a magnetic material, the core having a winding core, a first flange and a second flange provided at a first end and a second end, respectively, that are opposite to each other in the axial direction of the winding core, and a top plate located at a predetermined distance from the winding core and extending in a direction connecting the first flange and the second flange, a wire wound around the winding core, and a first terminal electrode and a second terminal electrode provided at the first flange and the second flange, respectively, to which the first and second terminals of the wire are connected, where the top plate corresponds to a member located at a predetermined distance from the winding core and arranged along the axial direction of the winding core.

[0009] The core has a gap located at a position on the top plate toward the second flange, which breaks a portion of the loop of magnetic flux passing through the winding core, the first flange, the second flange, and the top plate, and defines a gap that allows the wire to pass through.

[0010] In order to solve the above-mentioned technical problems, this invention is characterized in that at least a portion of the peripheral surface of the winding core portion is provided with a sloped surface that is inclined with respect to the axial direction, so that the circumferential length of the winding core portion becomes shorter as it approaches the first flange portion.

[0011] According to this invention, at least a portion of the peripheral surface of the winding core is provided with a sloped surface that is inclined with respect to the axial direction so that the circumferential length of the winding core becomes shorter toward the first flange, and tension applied to the wire being wound around the winding core tends to guide the wire down the sloped surface. As a result, when starting to wind the wire around the winding core, it is easy to move the wire toward one end in the axial direction of the winding core, or to apply a force that moves the wire toward one end in the axial direction of the winding core while the wire is being wound around the winding core.

[0012] FIG. 9 is a front view showing the appearance of a coil component 1 according to a first embodiment of the present invention. FIG. 10 is a front view showing a core 2 included in the coil component 1 shown in FIG. 1. FIG. 11 is a plan view of the core 2 shown in FIG. 2. FIG. 22 is a bottom view of the core 2 shown in FIG. 2. FIG. 23 is a right side view of the core 2 shown in FIG. 2. FIG. 24 is a perspective view of the core 2 shown in FIG. 2. FIG. 25 is a diagram for explaining an action that occurs when a wire 8 is wound around a winding core portion 3 included in the core 2 shown in FIG. 2. FIG. 9 is a front view showing a core 2a included in a coil component according to a second embodiment of the present invention. FIG. 9 is a front view showing a core 2b included in a coil component according to a third embodiment of the present invention. FIG. 9 is a plan view of the core 2b shown in FIG. 9. FIG. 9 is a bottom view of the core 2b shown in FIG. 9. FIG. 9 is a perspective view of the core 2c included in a coil component according to a fourth embodiment of the present invention.

[0013] A coil component 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 7. FIG.

[0014] The coil component 1 includes a core 2 made of a magnetic material. The core 2 is integrated with a winding core 3, a first flange 5 and a second flange 6 provided at a first end and a second end, respectively, that are opposite to each other in the axial direction A of the winding core 3, and a top plate 7 positioned at a predetermined distance from the winding core 3 and extending in a direction connecting the first flange 5 and the second flange 6.

[0015] The coil component 1 also includes a wire 8 wound around the winding core 3. In Fig. 1, the wire 8 is indicated by a thick line.

[0016] Furthermore, the coil component 1 includes a first terminal electrode 9 and a second terminal electrode 10 provided on the first flange portion 5 and the second flange portion 6, respectively, to which the first terminal and the second terminal of the wire 8, which are opposite to each other, are connected, respectively.

[0017] The following describes in more detail the configurations of the coil component 1 and the core 2. In the following description, as clearly shown in Figure 6, directions perpendicular to the axial direction A are defined as a width direction W and a height direction H, and the width direction W and the height direction H are defined as directions perpendicular to each other.

[0018] The core 2 is preferably made of ferrite or a resin containing metal magnetic powder. For example, the dimension of the core 2 in the axial direction A is 1.6 mm or more and 4.5 mm or less, and the dimension in the width direction W is 1.2 mm or more and 3.2 mm or less. Typically, the dimension in the axial direction A is longer than the dimension in the width direction W. The dimension in the height direction H is not particularly limited, but is generally 1.6 mm or more and 4.0 mm or less.

[0019] 1 to 6 , the first flange 5 and the second flange 6 are preferably provided so as to protrude in all directions, including the width direction W and the height direction H, from the first end and the second end of the winding core 3. Preferably, the top plate 7 is disposed along the axial direction A at a predetermined distance in the height direction H from the winding core 3, and the dimension in the width direction W is larger than the dimension in the width direction W defined by the outer periphery of the wire 8 wound around the winding core 3.

[0020] These configurations allow the core 2 to protect the wire 8 from the outside, thereby reducing the risk of any external object coming into contact with the wire 8 and damaging it.

[0021] The first terminal electrode 9 and the second terminal electrode 10 are provided on the opposite side of the first flange 5 and the second flange 6 in the height direction H from the side on which the top plate 7 is located. The terminal electrodes 9 and 10 are formed, for example, by baking a conductive paste containing silver and then plating it with nickel and tin. Alternatively, although not shown, the first terminal electrode 9 and the second terminal electrode 10 may be formed by attaching terminal members made of metal plates to the first flange 5 and the second flange 6 with an adhesive or by crimping.

[0022] The first and second terminals of the wire 8 are connected to the first terminal electrode 9 and the second terminal electrode 10, respectively, by, for example, thermocompression bonding or laser welding. In the state shown in Fig. 1 , the first and second terminals of the wire 8 are connected to the downward-facing surfaces of the first terminal electrode 9 and the second terminal electrode 10, respectively. However, the first and second terminals of the wire 8 may be connected to any locations on the first terminal electrode 9 and the second terminal electrode 10.

[0023] The wire 8 is wound around the winding core 3 in a spiral manner while advancing in the axial direction A. A coil component 1 having the wire 8 wound in this manner is sometimes called a horizontally wound inductor. Although the wire 8 shown in FIG. 1 is composed of a single wire, the wire 8 may be composed of two or more wires arranged in parallel in order to reduce electrical resistance without increasing the thickness of each individual wire. The method of winding the wire 8 around the winding core 3 and the state after winding will be described in detail later.

[0024] As schematically shown by arrow M in Fig. 1 , a magnetic flux loop is formed in the core 2, passing through the winding core 3, first flange 5, second flange 6, and top plate 7, but this magnetic flux loop is partially interrupted by a gap 11. The gap 11 defines a distance that allows the wire 8 to pass through, and is provided at a position on the top plate 7 that is offset toward the second flange 6. In this embodiment, the gap 11 is provided at a connection position between the top plate 7 and the second flange 6. In this way, the closer the gap 11 is provided to the second flange 6, the easier it is to wind the wire 8 over the entire area of ​​the winding core 3 in the axial direction A, and the effects of the characteristic configuration of this invention, which will be described later, are more effectively exhibited.

[0025] By controlling the size of the gap 11, the inductance and DC superposition characteristics of the coil component 1 can be balanced, and an inductor with an optimal balance can be obtained.

[0026] As described above, gap 11 defines the distance that allows wire 8 to pass through, and also functions to provide a path for guiding wire 8 from the outside of core 2 to around winding core portion 3. Gap 11 is set to a distance of, for example, 100 μm or more and 600 μm or less.

[0027] The winding core 3 has a rectangular cross section in a plane perpendicular to the axial direction A, and has a top surface 13 facing the top plate 7, a first side surface 15 and a second side surface 16 extending in a direction perpendicular to the top surface 13 and facing each other, and a bottom surface 17 extending parallel to the top surface 13 and connecting the first side surface 15 and the second side surface 16. Note that the ridges of the rectangular cross section of the winding core 3 may be chamfered or given a rounded surface, so that the cross section of the winding core 3 is not an exact rectangular shape but may be approximately rectangular.

[0028] The length of the winding core 3 in the circumferential direction becomes shorter as it approaches the first flange 5, and at least a part of the circumferential surface of the winding core 3 is provided with an inclined surface 19 that is inclined with respect to the axial direction A. In this embodiment, the top surface 13 is provided with an inclined surface 19 that is inclined with respect to the axial direction A so that the sum of the lengths of the top surface 13, the first side surface 15, and the second side surface 16 in the circumferential direction of the winding core 3 becomes shorter as it approaches the first flange 5.

[0029] By forming the winding core 3 in the above-described form, the following effects occur when the wire 8 is wound.

[0030] 7, when the wire 8 is to be wound around the winding core 3, first, the first end of the wire 8 is connected to the first terminal electrode 9. Next, the second end of the wire 8 is routed toward the second flange 6 and then guided into the gap 11. Next, after passing through the gap 11, the wire 8 is guided between the top plate 7 and the winding core 3 and is about to be wound around the winding core 3. At this time, tension T is applied to the wire 8.

[0031] When tension T is applied to the wire 8, a force represented by the vector B→C acts on the wire 8. This vector B→C can be broken down into a force B→D that tries to move the wire 8 in a direction toward the first flange 5, and a force B→E that presses the wire 8 against the inclined surface 19. Here, the greater the inclination of the inclined surface 19 with respect to the axial direction A, the more the force B→D can be increased and the force B→E can be decreased, and therefore the wire 8 can be guided more smoothly toward the first flange 5.

[0032] As described above, by guiding the wire 8 in the direction toward the first flange 5, when starting to wind the wire 8 around the winding core 3, it becomes easy to keep the wire 8 close to one end side in the axial direction of the winding core 3, i.e., the first flange 5 side. As a result, the limited dimension of the winding core 3 in the axial direction A can be effectively utilized to arrange the wire 8 around the winding core 3, so that the number of turns of the wire 8 around the winding core 3 can be increased and the inductance value of the coil device 1 can be increased.

[0033] The above-described steps are then repeated to continue winding the wire 8 around the winding core 3. That is, the second terminal side of the wire 8 is drawn toward the second flange 6, then guided into the gap 11, and then, after passing through the gap 11, the wire 8 is guided between the top plate 7 and the winding core 3 and wound around the winding core 3. At this time, while the wire 8 is being wound around the winding core 3, it is easy to apply a force that pulls the wire toward one end side in the axial direction A of the winding core 3, i.e., toward the first flange 5. After winding of the wire 8 is completed, the second terminal of the wire 8 is connected to the second terminal electrode 10.

[0034] When the characteristic configuration of this invention, i.e., at least a portion of the circumferential surface of the winding core 3 is provided with an inclined surface 19 that is inclined with respect to the axial direction A so that the circumferential length of the winding core 3 becomes shorter toward the first flange 5, functions most ideally, when winding of the wire 8 around the winding core 3 begins, the wire 8 is moved toward the first flange 5 in the axial direction A of the winding core 3, and while the wire 8 is being wound around the winding core 3, a force is applied that moves the wire 8 toward the first flange 5 in the axial direction A of the winding core 3, so that the wire 8 is wound in an aligned state around the winding core 3. When this state is realized, the winding shape of the wire 8 becomes most stable, and therefore the characteristics of the coil device 1 can be most stabilized.

[0035] 1 shows the multiple turns of wire 8 wound in an aligned state around winding core 3, but the winding state of wire 8 is not limited to this state. For example, the multiple turns of wire 8 may be in close contact with each other, or may be spaced apart from each other, or these states may be mixed. Furthermore, the degree of contact between the multiple turns may vary along the axial direction A of winding core 3, such as being lower on the first flange 5 side and higher on the second flange 6 side, or higher on the first flange 5 side and lower on the second flange 6 side.

[0036] Furthermore, as described above, the circumferential length of the winding core 3 is made shorter as it approaches the first flange 5, so that the length per turn of the wire 8 becomes shorter as it approaches the first flange 5 and longer as it approaches the second flange 6. This feature is similar to that of a conical coil. In a conical coil, the stray capacitance varies slightly for each turn of the wire, making it difficult for severe resonance to occur in the characteristics above the self-resonant frequency. A similar effect is also achieved in this embodiment.

[0037] 1, the gap 11 may be filled with a filler 21. The filler 21 is made of a resin or a resin containing magnetic powder.

[0038] The structure of the top plate portion 7 of the core 2 is similar to a cantilever structure when used alone, and the base of the beam is subjected to large stress when an external force is applied. However, when the filler 21 is provided, the cantilever structure can be eliminated. Therefore, even when an external force is applied to the top plate portion 7, stress can be reduced, making it less likely to break.

[0039] On the other hand, as shown in Figures 2 to 7, the filler 21 may not be provided. In this case, the gap 11 is filled with air. If there is too little air in the core 2, the characteristics of the magnetic material will be more pronounced, resulting in greater variation in the inductance value. This is because the relative permeability of the magnetic material varies more than that of air. On the other hand, if there is too much air, the characteristics of air will be more pronounced, reducing variation, but it will be difficult to obtain inductance because the relative permeability of air is μr = 1. Considering balance, it is preferable that the gap 11 be 100 μm or more and 600 μm or less in width, as mentioned above.

[0040] Fig. 8 is a front view showing a core 2a provided in a coil device according to a second embodiment of the present invention, and is a view corresponding to Fig. 2. In Fig. 8, elements corresponding to elements shown in Fig. 2 are given the same reference numerals, and duplicated explanations will be omitted.

[0041] The second embodiment is characterized in that a sloped surface 19 is provided on the top surface 13 of the winding core 3, and a sloped surface 19a is also provided on the bottom surface 17. The sloped surface 19a provided on the bottom surface 17 does not particularly function to move the wire toward one end of the winding core 3 in the axial direction, but it has the effect of increasing the symmetry of the shape of the winding core 3.

[0042] Figures 9 to 12 show a core 2b provided in a coil device according to a third embodiment of the present invention, with Figure 9 being a front view, Figure 10 being a plan view, Figure 11 being a bottom view, and Figure 12 being a perspective view. Figures 9, 10, 11, and 12 correspond to Figures 2, 3, 4, and 6, respectively. In Figures 9 to 12, elements corresponding to elements shown in Figures 2, 3, 4, and 6 are designated by the same reference numerals, and duplicate explanations will be omitted.

[0043] The third embodiment is characterized in that inclined surfaces 19b and 19c are provided on the first side surface 15 and the second side surface 16 of the winding core 3. Even when the inclined surfaces 19b and 19c are provided on the first side surface 15 and the second side surface 16, as in the case where the inclined surface 19 is provided on the top surface 13, when tension is applied to the wound wire, an action can be generated to pull the wire toward one end side in the axial direction of the winding core 3.

[0044] Fig. 13 is a front view showing a core 2c provided in a coil device according to a fourth embodiment of the present invention, and is a view corresponding to Fig. 2. In Fig. 13, elements corresponding to those shown in Fig. 2 are given the same reference numerals, and duplicated explanations will be omitted.

[0045] In the fourth embodiment, a sloped surface 19d is provided on the top surface 13 of the winding core portion 3, but the sloped surface 19d is not provided over the entire area of ​​the top surface 13 in the axial direction A, but is provided only on the portion of the top surface 13 on the first flange portion 5 side, and a non-slope surface 20 with no slope is provided on the second flange portion 6 side.

[0046] According to this embodiment, when tension is applied to the wound wire, the inclined surface 19d is provided in a portion on the first flange 5 side that is less likely to cause an action of pulling the wire toward one end in the axial direction of the winding core 3. Moreover, since the inclination of the inclined surface 19d can be made larger, the action of pulling the wire toward one end in the axial direction of the winding core 3 can be made stronger.

[0047] The feature in the above-described fourth embodiment that the inclined surface 19d is provided only on the portion of the top surface 13 on the side of the first flange portion 5 can also be applied to the third embodiment that has the feature that the inclined surfaces 19b and 19c are provided on the first side surface 15 and the second side surface 16 of the winding core portion 3, respectively.

[0048] In still another embodiment, the inclined surface 19 or 19d may be provided on the top surface 13 of the winding core 3, and the inclined surfaces 19b and 19c may be provided on the first side surface 15 and the second side surface 16. Furthermore, the area where the inclined surface 19 or 19d is provided on the top surface 13 and the area where the inclined surfaces 19b and 19c are provided on the first side surface 15 and the second side surface 16 may be arranged side by side in the axial direction A of the winding core 3.

[0049] Although the present invention has been described above with reference to the illustrated embodiment, various other modifications are possible within the scope of the present invention.

[0050] For example, in the illustrated embodiment, the cross section of the winding core 3 on a plane perpendicular to the axial direction A is rectangular or approximately rectangular, but it may be any other polygonal shape, or may be circular, elliptical, pseudo-circular, etc. Therefore, in the illustrated embodiment, the top surface 13 faces the top plate 7, but any part of the circumferential surface of the winding core may face the top plate, and for example, a ridge portion present on the circumferential surface of the winding core may face the top plate.

[0051] In the illustrated embodiment, the inclined surfaces 19, 19a, 19b, and 19c are formed as flat surfaces, but they may be formed as surfaces other than flat surfaces, for example, curved surfaces.

[0052] Furthermore, when configuring the coil component according to the present invention, partial substitution or combination of configurations is possible between the different embodiments described in this specification.

[0053] The present invention has the following embodiments.

[0054] <1> A core made of a magnetic material, the core having a winding core portion, a first flange portion and a second flange portion provided at a first end and a second end opposite to each other in the axial direction of the winding core portion, and a top plate portion located at a predetermined interval from the winding core portion and extending in a direction connecting the first flange portion and the second flange portion, and being integrated together; a wire wound around the winding core portion; and a first terminal electrode and a second terminal electrode provided at the first flange portion and the second flange portion, respectively, and connected to a first terminal end and a second terminal end of the wire opposite to each other, the core having a gap provided at a position offset toward the second flange portion in the top plate portion, the gap separating a part of a loop of magnetic flux passing through the winding core portion, the first flange portion, the second flange portion, and the top plate portion and defining a gap allowing the wire to pass through, a sloped surface that is inclined with respect to the axial direction is provided on at least a portion of the circumferential surface of the winding core portion so that the circumferential length of the winding core portion becomes shorter toward the first flange portion.

[0055] <2> The coil component according to <1>, wherein the winding core portion has a rectangular or substantially rectangular cross section in a plane perpendicular to the axial direction, and has a top surface facing the top plate portion, first and second side surfaces extending in a direction perpendicular to the top surface and facing each other, and a bottom surface extending parallel to the top surface and connecting the first and second side surfaces.

[0056] <3> The coil component according to <2>, wherein a total length of the top surface, the first side surface, and the second side surface in the circumferential direction of the winding core portion becomes shorter toward the first flange portion.

[0057] <4> The coil component according to <2> or <3>, wherein the inclined surface is provided on the top surface.

[0058] <5> The coil component according to <4>, wherein the inclined surface is provided over the entire area of ​​the top surface in the axial direction.

[0059] <6> The coil component according to <4>, wherein the inclined surface is provided only on a portion of the top surface on a side of the first flange portion.

[0060] <7> The coil component according to any one of <2> to <6>, wherein the inclined surfaces are provided on the first side surface and the second side surface.

[0061] <8> The coil component according to any one of <1> to <7>, wherein the gap is provided at a connection position of the top plate portion with the second flange portion.

[0062] REFERENCE SIGNS LIST 1 coil component 2, 2a, 2b, 2c core 3 winding core portion 5 first flange portion 6 second flange portion 7 top plate portion 8 wire 9 first terminal electrode 10 second terminal electrode 11 gap 13 top surface 15, 16 side surface 17 bottom surface 19, 19a, 19b, 19c, 19d inclined surface 20 non-inclined surface A axial direction M arrow indicating magnetic flux loop

Claims

1. A core made of a magnetic material, which is integrated with a winding core portion, a first flange portion and a second flange portion provided at a first end and a second end, respectively, that are opposite to each other in the axial direction of the winding core portion, and a top plate portion located at a predetermined distance from the winding core portion and extending in a direction connecting the first flange portion and the second flange portion; a wire wound around the winding core portion; and a first terminal electrode and a second terminal electrode provided on the first flange portion and the second flange portion, respectively, to which the opposite first terminal and second terminal of the wire are connected, respectively; wherein the core has a gap provided at a position offset toward the second flange portion in the top plate portion, which divides a part of the loop of magnetic flux passing through the winding core portion, the first flange portion, the second flange portion and the top plate portion and defines a gap that allows the wire to pass through; a circumferential surface of at least a portion of the circumferential surface of the winding core portion is provided with an inclined surface that is inclined with respect to the axial direction such that a circumferential length of the winding core portion becomes shorter toward the first flange portion.

2. The coil component according to claim 1, wherein the winding core portion has a rectangular or nearly rectangular cross section in a plane perpendicular to the axial direction, and has a top surface facing the top plate portion, first and second side surfaces extending in a direction perpendicular to the top surface and facing each other, and a bottom surface extending parallel to the top surface and connecting the first and second side surfaces.

3. A coil component as described in claim 2, wherein the sum of the lengths of the top surface, the first side surface, and the second side surface in the circumferential direction of the winding core portion becomes shorter toward the first flange portion.

4. A coil component according to claim 2 or 3, wherein the inclined surface is provided on the top surface.

5. The coil component according to claim 4, wherein the inclined surface is provided over the entire area of ​​the top surface in the axial direction.

6. The coil component according to claim 4, wherein the inclined surface is provided only on the portion of the top surface facing the first flange portion.

7. A coil component according to any one of claims 2 to 6, wherein the inclined surface is provided on the first side surface and the second side surface.

8. A coil component according to any one of claims 1 to 7, wherein the gap is provided at a position where the top plate portion is connected to the second flange portion.

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