Coil component

Abstract

An ith turn (where i is an integer of 1 to (N − 1)) belonging to a first portion (P1) of a second wire (60) is positioned between valleys of the ith turn and the (i + 1)th turn of a first wire (50). At least part of an Nth turn belonging to a second portion (P2) of the second wire (60) is positioned between valleys of two adjacent turns of the first portion (P1). At least part of an (N + 1)th turn of the second wire (60) is positioned between valleys of two adjacent turns of the first portion (P1). At least part of a jth turn (where j is an integer of (N + 2) to 2N) belonging to a third portion (P3) of the second wire (60) is positioned between valleys of a (j − 1)th turn and the jth turn of the first wire (50).

Description

Coil parts

[0001] The present disclosure relates to a coil component.

[0002] The coil component described in Patent Document 1 includes a winding core, a first flange, and a second flange. The winding core is rectangular prism-shaped. The first flange is connected to a first end of the winding core. The second flange is connected to a second end of the winding core. The coil component also includes four external electrodes, a first wire, and a second wire. Two of the four external electrodes are located on the surface of the first flange. The remaining two external electrodes are located on the surface of the second flange.

[0003] The first wire is wound directly around the winding core. A first end of the first wire is connected to the external electrode on the first flange. A second end of the first wire is connected to the external electrode on the second flange. The second wire is wound around the winding core from the outside of the first wire. A first end of the second wire is connected to the external electrode on the first flange. A second end of the second wire is connected to the external electrode on the second flange. The second wire is wound around the outside of the first wire in the same direction as the first wire.

[0004] U.S. Pat. No. 1,055,9415

[0005] In a coil component such as that described in Patent Document 1, stray capacitance may occur at a location where the first wire and the second wire contact each other. Furthermore, the greater the difference in the number of turns between the first wire and the second wire at the contact location, the greater the stray capacitance.

[0006] Here, the stray capacitance generated when the potential of the first wire is one turn higher than the potential of the second wire when comparing the contacting turns of the first wire and the contacting turns of the second wire is defined as a positive unit capacitance. Furthermore, the stray capacitance generated when the potential of the second wire is one turn higher than the potential of the first wire when comparing the contacting turns of the first wire and the contacting turns of the second wire is defined as a negative unit capacitance. In this case, a smaller difference between the sum of the positive unit capacitances and the sum of the negative unit capacitances is preferable because the value of the stray capacitance of the entire coil component approaches zero. However, in some coil components, the total number of turns of each wire is an even number, and some turns of the second wire are wound outside the other turns of the second wire. With such a wire winding method, it may be difficult to achieve a zero difference between the sum of the positive unit capacitances and the sum of the negative unit capacitances.

[0007] In order to solve the above problems, the present disclosure provides a winding core, a first flange provided at a first end of the winding core in a direction along a central axis, a second flange provided at a second end of the winding core opposite to the first end, first and second external electrodes provided at the first flange, third and fourth external electrodes provided at the second flange, a first wire wound around the winding core, a first wire end connected to the first external electrode and a second wire end connected to the third external electrode, and a second wire end wound around the winding core in the same direction as the first wire, the first wire end being connected to the front external electrode. a second wire connected to the second external electrode and having a second wire end connected to the fourth external electrode, wherein the number of turns of the first wire and the second wire increases by one for each full turn around the central axis from the first wire end toward the second wire end, and when N is an integer equal to or greater than 4, the total number of turns of the first wire and the second wire is 2N, the first wire is wound directly around the winding core, and a first portion of the second wire including the first turn to the (N-1)th turn is perpendicular to the central axis. a second portion including the Nth turn to the (N+1)th turn of the second wire is wound directly from the outside of the first wire in a direction perpendicular to the central axis; a third portion including the (N+2)th turn to the 2Nth turn of the second wire is wound directly from the outside of the first wire in a direction perpendicular to the central axis; and the i-th turn (where i is an integer of 1 to N-1) of the second wire belonging to the first portion is wound directly from the outside of the first wire. a coil component in which at least a portion of the Nth turn belonging to the second portion of the second wire is located in the valley between two adjacent turns of the first portion, at least a portion of the (N+1)th turn of the second wire is located in the valley between two adjacent turns of the first portion, and at least a portion of the jth turn (where j is an integer greater than or equal to N+2 and less than or equal to 2N) belonging to the third portion of the second wire is located in the valley between the (j-1)th turn and the jth turn of the first wire.

[0008] The present disclosure also provides a winding core, a first flange provided at a first end of the winding core in a direction along a central axis, a second flange provided at a second end of the winding core opposite to the first end, first and second external electrodes provided at the first flange, third and fourth external electrodes provided at the second flange, a first wire wound around the winding core, with a first wire end connected to the first external electrode and a second wire end connected to the third external electrode, and a fourth external electrode wound around the winding core in the same direction as the first wire, with the first wire end connected to the second external electrode. a second wire connected to the fourth external electrode and having a second wire end connected to the fourth external electrode, wherein the number of turns of the first wire and the second wire increases by one for each full turn around the central axis from the first wire end toward the second wire end, and when N is an integer equal to or greater than 4, the total number of turns of the first wire and the total number of turns of the second wire is 2N, the first wire is wound directly around the winding core, and the first turn of the second wire is adjacent to and in front of the first turn of the first wire in a direction along the central axis. a first portion including a second turn to an Nth turn of the second wire is wound directly around the first wire from the outside in a direction perpendicular to the central axis; a second portion including an (N+1)th turn of the second wire is wound directly around the first portion from the outside in a direction perpendicular to the central axis; a third portion including an (N+2)th turn to an 2Nth turn of the second wire is wound directly around the first wire from the outside in a direction perpendicular to the central axis; at least a portion of the i-th turn (where i is an integer between 2 and N) belonging to the first portion is located in a valley between the i-th turn and the (i+1)-th turn of the first wire, the second portion is located in a valley between two adjacent turns of the first portion in a direction perpendicular to the central axis, at least a portion of the j-th turn (where j is an integer between N+2 and 2N) belonging to the third portion of the second wire is located in a valley between the (j-1)-th turn and the j-th turn of the first wire, and the first turn of the second wire isThe coil component is spaced apart from the second turn of the first wire continuously for 0.5 turns or more.

[0009] According to the above configuration, when the total number of turns of the first wire and the second wire is an even number, it is possible to suppress the imbalance between the positive stray capacitance and the negative stray capacitance.

[0010] Fig. 1 is a perspective view of a coil component according to a first embodiment. Fig. 2 is a schematic end view showing a portion of the coil component according to the first embodiment, the portion including the central axis and perpendicular to the left-right axis. Fig. 3 is a schematic end view showing a portion of a coil component according to a second embodiment, the portion including the central axis and perpendicular to the left-right axis. Fig. 4 is a schematic end view showing a portion of a coil component according to a modified example, the portion including the central axis and perpendicular to the left-right axis. Fig. 5 is a schematic end view showing a portion of a coil component according to a modified example, the portion including the central axis and perpendicular to the left-right axis.

[0011] Hereinafter, an embodiment of a coil component will be described with reference to the drawings. Note that the drawings may show components enlarged to facilitate understanding. The dimensional ratios of the components may differ from those in the actual drawings or from those in other drawings.

[0012] First Embodiment <Overall Configuration> As shown in FIG. 1, a coil device 10 includes a drum core 10C and a planar core 10F.

[0013] The drum core 10C has a winding core 11, a first flange 21, and a second flange 31. The winding core 11 has a rectangular prism shape and is made of a material such as Ni-Zn ferrite.

[0014] The first flange 21 is provided at a first end in the direction along the central axis C of the winding core 11. Specifically, the first flange 21 is connected to the first end in the direction along the central axis C of the winding core 11. The second flange 31 is provided at a second end in the direction along the central axis C of the winding core 11. Specifically, the second flange 31 is connected to the second end in the direction along the central axis C of the winding core 11. The first flange 21 and the second flange 31 are made of the same material as the winding core 11. Furthermore, the first flange 21 and the second flange 31 are integrally molded with the winding core 11.

[0015] Here, an axis parallel to the central axis C is defined as the core axis X. A specific axis perpendicular to the core axis X is defined as the vertical axis Y. In the first embodiment, the vertical axis Y is a direction perpendicular to the mounting surface when the coil component 10 is mounted on a substrate. When viewed in a direction along the core axis X, the vertical axis Y is parallel to the short side of the winding core portion 11. An axis perpendicular to both the core axis X and the vertical axis Y is defined as the left-right axis Z. In the first embodiment, when viewed in a direction along the core axis X, the left-right axis Z is parallel to the long side of the winding core portion 11. One of the directions along the core axis X is defined as the positive direction X1, and the direction opposite to the positive direction X1 is defined as the negative direction X2. In the first embodiment, the positive direction X1 coincides with the direction from the winding core portion 11 toward the first flange portion 21. The negative direction X2 coincides with the direction from the winding core portion 11 toward the second flange portion 31. Furthermore, one of the directions along the vertical axis Y is referred to as the upward direction Y1, and the direction opposite to the upward direction Y1 is referred to as the downward direction Y2. Furthermore, one of the directions along the left-right axis Z is referred to as the rightward direction Z1, and the direction opposite to the rightward direction Z1 is referred to as the leftward direction Z2. Note that the upward direction Y1 and downward direction Y2 mentioned here are named for convenience and do not specify the direction of gravity. Furthermore, the rightward direction Z1 and leftward direction Z2 are named for convenience and do not limit the left-right direction from a particular viewpoint.

[0016] In this disclosure, the term "upper surface" refers to a surface facing the upward direction Y1 in the direction along the vertical axis Y, and the term "lower surface" refers to a surface facing the downward direction Y2. The "upper surface" does not necessarily have to be orthogonal to the upward direction Y1. For example, the "upper surface of the coil component 10" refers to a surface that can be seen when the coil component 10 is viewed from the upward direction Y1 toward the downward direction Y2. The same applies to the lower surface.

[0017] When viewed in a direction along the central axis C, the first flange 21 protrudes outward relative to the winding core 11 in directions along the vertical axis Y and the horizontal axis Z. The first flange 21 has a shape that is plane-symmetrical with respect to an imaginary plane that includes the central axis C and is perpendicular to the horizontal axis Z.

[0018] The first flange 21 has a main body 22 and a recess 23. The main body 22 is generally rectangular and has a thin thickness along the central axis C. When viewed in the negative direction X2, both edges of the main body 22 on the upper Y1 side and the lower Y2 side are parallel to the left-right axis Z. When viewed in the negative direction X2, both edges of the main body 22 on the left Z2 side and the right Z1 side are parallel to the up-down axis Y.

[0019] The recessed portion 23 is recessed downward in the Y2 direction from the upper surface of the main body portion 22. The dimension of the recessed portion 23 along the left-right axis Z decreases as it goes downward in the Y2 direction. The recessed portion 23 is located approximately in the center of the main body portion 22 along the left-right axis Z. The dimension of the recessed portion 23 along the central axis C is the same as the dimension of the main body portion 22 along the central axis C. In other words, a portion of the first flange portion 21 on the upward Y1 side has a bifurcated shape with the recessed portion 23 in between.

[0020] The second flange 31 and the first flange 21 have shapes that are plane-symmetrical with respect to an imaginary plane that passes through the center of the winding core 11 and is perpendicular to the central axis C. That is, when viewed from the direction along the central axis C, the second flange 31 protrudes outward from the winding core 11 in the directions along the vertical axis Y and the horizontal axis Z. The second flange 31 has a main body 32 and a recessed portion 33. The configurations of the main body 32 and the recessed portion 33 of the second flange 31 are similar to those of the main body 22 and the recessed portion 23 of the first flange 21. That is, the recessed portion 33 is recessed downward in the Y2 direction from the top surface of the main body 32.

[0021] The plate core 10F has a rectangular plate shape. The long sides of the plate core 10F are parallel to the central axis C. The short sides of the plate core 10F are parallel to the left-right axis Z. The plate core 10F is located on the downward direction Y2 side of the drum core 10C. The plate core 10F is connected to both the lower surface of the first flange portion 21 and the lower surface of the second flange portion 31. In other words, the plate core 10F is bridged between the first flange portion 21 and the second flange portion 31. The material of the plate core 10F is the same as the material of the drum core 10C.

[0022] The coil component 10 includes a first external electrode 41, a second external electrode 42, a third external electrode 43, and a fourth external electrode 44. The first external electrode 41 is provided on the first flange 21. That is, the first external electrode 41 is attached to the surface of the first flange 21. The first external electrode 41 is located on the surface of the first flange 21 on the upward Y1 side, and on the leftward Z2 side with respect to the recess 23.

[0023] The second external electrode 42 is provided on the first flange 21. That is, the second external electrode 42 is attached to the surface of the first flange 21. The second external electrode 42 is located on the surface of the first flange 21 on the upward Y1 side, and on the rightward Z1 side with respect to the recess 23.

[0024] The third external electrode 43 is provided on the second flange 31. That is, the third external electrode 43 is attached to the surface of the second flange 31. The third external electrode 43 is located on the surface of the second flange 31 on the upward Y1 side and on the leftward Z2 side with respect to the recess 33.

[0025] The fourth external electrode 44 is provided on the second flange 31. That is, the fourth external electrode 44 is attached to the surface of the second flange 31. The fourth external electrode 44 is located on the surface of the second flange 31 on the upward Y1 side, and on the rightward Z1 side with respect to the recess 33.

[0026] Although not shown, the first to fourth external electrodes 41 to 44 have a metal layer and a plating layer. The metal layer is, for example, a layer mainly composed of silver. The plating layer is made up of a plurality of layers, for example, a layer mainly composed of copper, a layer mainly composed of nickel, and a layer mainly composed of tin. In this embodiment, the surface of the coil component 10 on which the first to fourth external electrodes 41 to 44 are provided is the surface that faces the substrate when the coil component 10 is mounted on the substrate. Note that in FIG. 1, the first to fourth external electrodes 41 to 44 are shown by dashed dotted lines.

[0027] <Configuration of the First Wire and the Second Wire> As shown in Fig. 1 , the coil device 10 includes a first wire 50 and a second wire 60. The first wire 50 and the second wire 60 have portions wound around the winding core 11. Note that Fig. 1 simplifies the winding structure of the portions of the first wire 50 and the second wire 60 that are wound around the winding core 11, and illustrates each turn of each wire as if they were a cylindrical object integrated together.

[0028] Although not shown in the figures, the first wire 50 has a conductor and an insulating coating. The insulating coating covers the outer surface of the conductor. The first wire 50 has a substantially circular shape in a cross section perpendicular to the direction in which the first wire 50 extends. The first wire 50 has a first wire end 51 and a second wire end 52 opposite the first wire end 51. In each figure, the first wire 50 is colored with dots.

[0029] 1 , a first wire end 51 of the first wire 50 is connected to the first external electrode 41. A second wire end 52 of the first wire 50 is connected to the third external electrode 43. Here, when tracing the first wire 50 from the first wire end 51 to the second wire end 52, the point where the first wire 50 first comes into contact with the outer circumferential surface of the winding core 11 is defined as the 1.0 turn point of the first wire 50. In the first embodiment, the 1.0 turn point of the first wire 50 is located on a ridgeline on the rightward Z1 side and upward Y1 side of the winding core 11.

[0030] As shown in FIG. 2 , the number of turns of the first wire 50 increases by one each time the first wire 50 makes one revolution around the central axis C from the first wire end 51 to the second wire end 52. When viewed in the negative direction X2, the first wire 50 is wound around the winding core 11 so that the number of turns increases clockwise. Therefore, for example, when viewed in the negative direction X2, a point 36 degrees from the 1.0 turn point of the first wire 50 around the central axis C is the 1.1 turn point of the first wire 50. The first turn of the first wire 50 refers to the portion of the first wire 50 from the 1.0 turn point to just before the 2.0 turn point of the first wire 50. The final turn of the first wire 50 is the turn that includes the last contact point with the outer circumferential surface of the winding core 11 when tracing the first wire 50 from the first wire end 51 to the second wire end 52. 2 to 5, any position within the range of the first turn is indicated as "1." The same applies to other numbers of turns. The number of turns shown in FIG. 2 does not have to match the number of turns counted from the start of winding during manufacturing.

[0031] As shown in Fig. 1, the second wire 60 has a similar configuration to the first wire 50. That is, the second wire 60 has a conductor and an insulating coating. The insulating coating covers the outer surface of the conductor. The second wire 60 has a substantially circular shape in a cross section perpendicular to the direction in which the second wire 60 extends. The second wire 60 has a first wire end 61 and a second wire end 62 opposite the first wire end 61.

[0032] 1 , a first wire end 61 of the second wire 60 is connected to the second external electrode 42. A second wire end 62 of the second wire 60 is connected to the fourth external electrode 44. Here, when tracing the second wire 60 from the first wire end 61 to the second wire end 62, the first point whose angular position about the central axis C matches the angular position of the 1.0 turn point of the first wire 50 is defined as the 1.0 turn point of the second wire 60. That is, in the first embodiment, when viewed in a direction along the central axis C, the 1.0 turn point of the second wire 60 is located on a straight line connecting the ridge line on the rightward direction Z1 side and upward direction Y1 side of the winding core portion 11 and the central axis C.

[0033] 2 , the number of turns of the second wire 60 increases by one each time the second wire 60 makes one revolution around the central axis C from the first wire end 61 to the second wire end 62. When viewed in the negative direction X2, the second wire 60 is wound around the winding core 11 so that the winding progresses clockwise as the number of turns increases. In other words, the second wire 60 is wound around the winding core 11 in the same direction as the first wire 50. The number of turns of the second wire 60 is counted in the same way as the first wire 50.

[0034] The first turn of the first wire 50 refers to the section from the 1.0 turn position to just before the 2.0 turn position of the first wire 50. The same applies to the second wire 60. The final turn of the first wire 50 refers to the turn that includes the last contact position with the outer circumferential side of the winding core 11 when tracing the first wire 50 from the first wire end 51 to the second wire end 52.

[0035] Furthermore, with regard to the first wire 50 and the second wire 60, the portion wound from the outside in a direction perpendicular to the central axis C around the valley portion formed by two adjacent turns of the first layer L1 in the direction along the central axis C is referred to as the second layer L2.

[0036] Furthermore, with respect to the first wire 50 and the second wire 60, the portion wound from the outside in a direction perpendicular to the central axis C around the valley portion formed by two adjacent turns of the second layer L2 in the direction along the central axis C is referred to as the third layer L3.

[0037] <Regarding the Wire Winding Mode of the First Embodiment> As shown in Fig. 2 , all turns of the first wire 50 belong to the first layer L1. That is, all turns of the first wire 50 are wound directly around the winding core 11. The first wire 50 is wound from the first turn to the tenth turn. That is, when N is 5, the total number of turns of the first wire 50 is 2N.

[0038] The first to tenth turns of the first wire 50 are wound in order such that the increasing number of turns leads to a position closer to the second flange 31 in the direction along the central axis C. Furthermore, the first to tenth turns of the first wire 50 are wound adjacent to each other in the direction along the central axis C. Here, "wound adjacent to each other" does not necessarily mean that the turns of adjacent wires are in contact with each other. Even if the turns of adjacent wires are not in contact with each other, they can be said to be adjacent as long as there is no other wire on the line connecting the centers of the adjacent wires when viewed cross-sectionally.

[0039] The second wire 60 is wound from the first turn to the tenth turn. That is, when N is 5, the total number of turns of the second wire 60 is 2N. The second wire 60 has a first portion P1, a second portion P2, and a third portion P3.

[0040] The first portion P1 includes the first turn through a portion of the fourth turn of the second wire 60. In other words, when N is 5, the first portion P1 includes the first turn through the (N-1)th turn of the second wire 60. The first portion P1 is wound directly around the first wire 50 from the outside in a direction perpendicular to the central axis C. Note that "the first portion P1 includes the first turn through the (N-1)th turn of the second wire 60" means that at least a portion of the first turn through at least a portion of the (N-1)th turn of the second wire 60 is wound directly around the first wire 50 from the outside. Note that a portion of the fourth turn of the second wire 60, including an end of the fourth turn on the third turn side, is wound directly around the first wire 50 from the outside. Therefore, this portion is included in the first portion P1. On the other hand, a portion of the fourth turn of the second wire 60, including an end of the fourth turn on the fifth turn side, is wound around the second wire 60 from the outside. Therefore, this portion is not included in the first portion P1.

[0041] The first turn of the second wire 60 is located in the valley between the first and second turns of the first wire 50. The second turn of the second wire 60 is located in the valley between the second and third turns of the first wire 50. The third turn of the second wire 60 is located in the valley between the third and fourth turns of the first wire 50. A portion of the fourth turn of the second wire 60 is located in the valley between the fourth and fifth turns of the first wire 50. In this way, at least a portion of the i-th turn (where i is an integer greater than or equal to 1 and less than N-1) belonging to the first portion P1 of the second wire 60 is located in the valley between the i-th turn and the (i+1)-th turn of the first wire 50. Note that "at least a portion of the i-th turn of the second wire 60 is located in the valley between the i-th turn and the (i+1)-th turn of the first wire 50" includes a case where the entire i-th turn is not located in the valley between the i-th turn and the (i+1)-th turn of the first wire 50, but only a portion of the i-th turn is located in the valley of the corresponding turn. This also applies to the following description.

[0042] The second portion P2 is a portion of the fifth and sixth turns of the second wire 60. In other words, when N is 5, the second portion P2 includes the Nth to (N+1)th turns of the second wire 60. Note that "the second portion P2 includes the Nth to (N+1)th turns of the second wire 60" means that at least a portion of the Nth turn and at least a portion of the (N+1)th turn of the second wire 60 are wound directly from the outside around the first portion P1. Note that a portion of the sixth turn of the second wire 60, including the end of the sixth turn on the fifth turn side, is wound directly from the outside around the second wire 60. Therefore, this portion is included in the second portion P2. On the other hand, a portion of the sixth turn of the second wire 60, including the end of the sixth turn on the seventh turn side, is wound from the outside around the first wire 50. Therefore, this portion is not included in the second portion P2.

[0043] The fifth turn of the second wire 60 is located in the valley between the second and third turns of the second wire 60. That is, when N is 5, at least a portion of the Nth turn of the second wire 60 is located in the valley between the (N-3)th and (N-2)th turns of the second wire 60. In this way, at least a portion of the Nth turn belonging to the second portion P2 of the second wire 60 is located in the valley between two adjacent turns of the first portion P1.

[0044] At least a portion of the sixth turn of the second wire 60 is located in the valley between the third and fourth turns of the second wire 60. That is, when N is 5, at least a portion of the (N+1)th turn of the second wire 60 is located in the valley between the (N-2)th and (N-1)th turns of the second wire 60. In this way, at least a portion of the (N+1)th turn of the second wire 60 is located in the valley between two adjacent turns of the first portion P1.

[0045] The third portion P3 includes the seventh turn through the tenth turn of the second wire 60. In other words, when N is 5, the third portion P3 includes the (N+2)th turn through the 2Nth turn of the second wire 60. The third portion P3 is wound directly around the first wire 50 from the outside in a direction perpendicular to the central axis C. Note that "the third portion P3 includes the (N+2)th turn through the 2Nth turn of the second wire 60" means that at least a portion of the (N+1)th turn and at least a portion of the 2Nth turn of the second wire 60 are wound directly around the first wire 50 from the outside.

[0046] The seventh turn of the second wire 60 is located in the valley between the sixth and seventh turns of the first wire 50. The eighth turn of the second wire 60 is located in the valley between the seventh and eighth turns of the first wire 50. The ninth turn of the second wire 60 is located in the valley between the eighth and ninth turns of the first wire 50. The tenth turn of the second wire 60 is located in the valley between the ninth and tenth turns of the first wire 50. In this way, at least a part of the j-th turn (where j is an integer greater than or equal to N+2 and less than or equal to 2N) belonging to the third portion P3 of the second wire 60 is located in the valley between the (j-1)-th turn and the j-th turn of the first wire 50.

[0047] <Regarding stray capacitance in the first embodiment> In the following description, it is assumed that the same positive voltage is applied to the first line end 51 of the first wire 50 and the first line end 61 of the second wire 60, and that a ground voltage is applied as a reference voltage to the second line end 52 of the first wire 50 and the second line end 62 of the second wire 60.

[0048] The greater the difference in the number of turns between the turns of the first wire 50 that contact the turns of the second wire 60, the greater the stray capacitance generated between adjacent turns of each wire. For example, as shown in FIG. 2 , the turns of the first wire 50 that contact the first turn of the second wire 60 are the first and second turns. In this case, there is no significant potential difference between the first turn of the second wire 60 and the first turn of the first wire 50. However, when comparing the potential of the first turn of the second wire 60 with the potential of the second turn of the first wire 50, the potential of the first turn of the second wire 60 is higher. Therefore, a stray capacitance corresponding to this potential difference is generated between the first turn of the second wire 60 and the second turn of the first wire 50.

[0049] Here, when comparing the contacting turns of the first wire 50 and the second wire 60, the stray capacitance generated by the potential of the second wire 60 being one turn higher than the potential of the first wire 50 is defined as a negative unit capacitance A.

[0050] When negative unit capacitance A is defined as above, when comparing the contacting turns of first wire 50 and second wire 60, the stray capacitance generated when the potential of first wire 50 is one turn higher than the potential of second wire 60 is positive unit capacitance B. Positive unit capacitance B has the same absolute value as negative unit capacitance A but is an opposite value.

[0051] In the first embodiment, the coil component 10 has four negative unit capacitances A and four positive unit capacitances B. Therefore, when viewed as a whole, the positive stray capacitance and the negative stray capacitance are approximately the same value. In other words, the stray capacitance generated by the high potential of the first wire 50 and the stray capacitance generated by the high potential of the second wire 60 are approximately the same.

[0052] <Effects of the First Embodiment> (1-1) In the first embodiment, the total number of turns of each wire of the coil component 10 is an even number. In addition, some turns of the second wire 60 in the coil component 10 are wound outward relative to other turns of the second wire 60. While assuming such a wire winding configuration, winding the second wire 60 as in the first embodiment makes it possible to cancel out the positive stray capacitance and the negative stray capacitance. In other words, it is possible to suppress bias in the stray capacitance of the coil component 10 as a whole.

[0053] (1-2) In the first embodiment, all turns of the second wire 60 are wound directly outward from the direction along the central axis C around the first wire 50 or the second wire 60. In other words, the second wire 60 is not wound directly around the winding core 11. Therefore, compared to a configuration in which all turns of the first wire 50 and any turns of the second wire 60 are wound directly around the winding core 11, the area around which the wire is wound on the winding core 11 can be made smaller. By reducing the area around which the wire is wound, a design that reduces the length of the winding core 11 in the direction along the central axis C becomes possible.

[0054] (1-3) At least a portion of the Nth turn of the second wire 60 is located in the valley between the (N-3)th and (N-2)th turns of the second wire 60. At least a portion of the (N+1)th turn of the second wire 60 is located in the valley between the (N-2)th and (N-1)th turns of the second wire 60. With this configuration, the Nth and (N+1)th turns of the second wire 60 are less likely to cross each other, and the second wire 60 is less likely to become unwound.

[0055] Second Embodiment A second embodiment of the coil component will be described below. In the coil component of the second embodiment, the basic configurations of the drum core 10C, the planar core 10F, the first wire 50, the second wire 60, and the first external electrode 41 to the fourth external electrode 44 are the same as those of the first embodiment. The following describes the winding manner of the first wire 50 and the winding manner of the second wire 60, which are different from those of the first embodiment.

[0056] <Regarding the Wire Winding Mode of the Second Embodiment> As shown in Fig. 3 , all turns of the first wire 50 belong to the first layer L1. That is, all turns of the first wire 50 are wound directly around the winding core 11. The first wire 50 is wound from the first turn to the eighth turn. That is, when N is 4, the total number of turns of the first wire 50 is 2N.

[0057] The first to eighth turns of the first wire 50 are wound in order such that the greater the number of turns, the closer the turns are to the second flange 31 in the direction along the central axis C. The first to eighth turns of the first wire 50 are wound adjacent to each other in the direction along the central axis C.

[0058] The second wire 60 is wound from the first turn to the eighth turn. That is, when N is 4, the total number of turns of the second wire 60 is 2N. The first turn of the second wire 60 is adjacent to the first turn of the first wire 50 in the direction along the central axis C and is wound directly around the winding core 11. In the second embodiment, the first turn of the second wire 60 is located closer to the first flange 21 than the first turn of the first wire 50 in the direction along the central axis C. Note that, since the first turn of the first wire 50 is located in the valley between the first turn and the second turn of the first wire 50, the first turn of the second wire 60 is continuously separated from the second turn of the first wire 50 by 0.5 turns or more. In this embodiment, the first turn of the second wire 60 is continuously separated from the second turn of the first wire 50 by one turn or more.

[0059] The second wire 60 has a first portion P1, a second portion P2, and a third portion P3. The first portion P1 is a portion of the second to fourth turns of the second wire 60. In other words, when N is 4, the first portion P1 includes the second to Nth turns of the second wire 60. The first portion P1 is wound directly from the outside of the first wire 50 in a direction perpendicular to the central axis C. Note that a portion of the fourth turn of the second wire 60, including the end of the fourth turn on the third turn side, is wound directly from the outside of the first wire 50. Therefore, this portion is included in the first portion P1. On the other hand, a portion of the fourth turn of the second wire 60, including the end of the fourth turn on the fifth turn side, is wound from the outside of the second wire 60. Therefore, this portion is not included in the first portion P1.

[0060] The second turn of the second wire 60 is located in the valley between the second and third turns of the first wire 50. Furthermore, the third turn of the second wire 60 is located in the valley between the third and fourth turns of the first wire 50. A portion of the fourth turn of the second wire 60 is located in the valley between the fourth and fifth turns of the first wire 50. In this way, at least a portion of the i-th turn (where i is an integer between 2 and N) belonging to the first portion P1 of the second wire 60 is located in the valley between the i-th turn and the (i+1)-th turn of the first wire 50.

[0061] The second portion P2 is a portion of the fifth turn of the second wire 60. In other words, when N is 4, the second portion P2 includes at least a portion of the (N+1)th turn of the second wire 60. A portion of the fifth turn of the second wire 60, including an end on the fourth turn side, is located in the valley between the third and fourth turns of the second wire 60. That is, the second portion P2 is located in the valley between two adjacent turns of the first portion P1. Note that a portion of the fifth turn of the second wire 60, including an end on the fourth turn side, is wound directly from the outside around the first portion P1. Therefore, this portion is included in the second portion P2. On the other hand, a portion of the fifth turn of the second wire 60, including an end on the sixth turn side, is wound from the outside around the first wire 50. Therefore, this portion is not included in the first portion P1.

[0062] The third portion P3 includes the sixth to eighth turns of the second wire 60. In other words, when N is 4, the third portion P3 includes the (N+2)th to 2Nth turns of the second wire 60. The third portion P3 is wound directly around the first wire 50 from the outside in a direction perpendicular to the central axis C.

[0063] The sixth turn of the second wire 60 is located in the valley between the fifth and sixth turns of the first wire 50. The seventh turn of the second wire 60 is located in the valley between the sixth and seventh turns of the first wire 50. The eighth turn of the second wire 60 is located in the valley between the seventh and eighth turns of the first wire 50. In this way, at least a part of the jth turn (where j is an integer greater than or equal to N+2 and less than or equal to 2N) belonging to the third portion P3 of the second wire 60 is located in the valley between the (j-1)th turn and the jth turn of the first wire 50.

[0064] <Regarding stray capacitance in the second embodiment> In the following description, it is assumed that the same positive voltage is applied to the first line end 51 of the first wire 50 and the first line end 61 of the second wire 60, and that a ground voltage as a reference voltage is applied to the second line end 52 of the first wire 50 and the second line end 62 of the second wire 60. The definitions of negative unit capacitance A and positive unit capacitance B are the same as in the first embodiment.

[0065] In the second embodiment, the coil component 10 has three negative unit capacitances A and three positive unit capacitances B. Therefore, when viewed as a whole, the positive stray capacitance and the negative stray capacitance are approximately the same value. In other words, the stray capacitance generated due to the high potential of the first wire 50 and the stray capacitance generated due to the high potential of the second wire 60 are approximately the same.

[0066] <Effects of the Second Embodiment> In the second embodiment, in addition to the effect (1-1) of the first embodiment, the following effect can be further obtained.

[0067] (2-1) In the second embodiment, the first turn of the second wire 60 is adjacent to the first turn of the first wire 50 in the direction along the central axis C and is wound directly around the winding core 11. Furthermore, the first turn of the second wire 60 is continuously separated from the second turn of the first wire 50 by 0.5 turns or more. In this way, by separating the first turn of the first wire 50 and the first turn of the second wire 60, the stray capacitance generated between the corresponding turns can be reduced. In other words, it is possible to prevent imbalances in the stray capacitance of the coil device 10 as a whole.

[0068] <Modifications> The first and second embodiments can be modified as follows: The first and second embodiments and the following modifications can be combined and implemented within a range that does not cause technical contradictions.

[0069] In the first and second embodiments, the configuration of the coil component 10 is not limited to the above configuration. For example, the coil component 10 does not need to include the planar core 10F. Furthermore, the shape of the planar core 10F is not limited to a rectangular plate. For example, the planar core 10F may be an elliptical plate.

[0070] In the first and second embodiments, the shape of the winding core 11 is not limited to the examples of the above embodiments. For example, the shape of the winding core 11 may be a cylindrical shape or a polygonal prism shape other than a quadrangular prism.

[0071] In the first and second embodiments, the materials of the drum core 10C and the plate core 10F are not limited to those described in the above embodiments. For example, the materials of the drum core 10C and the plate core 10F are not limited to Ni-Zn ferrite, but may be Mn-Zn ferrite, etc. Furthermore, the materials of the drum core 10C and the plate core 10F may be ferrite, alumina, synthetic resin, a mixture thereof, etc.

[0072] In the first and second embodiments, the configuration of the drum core 10C is not limited to the examples of the above embodiments. For example, the first flange 21 may not have the recess 23. In this case, it is sufficient that the first external electrode 41 and the second external electrode 42 are spaced apart from each other. The same applies to the second flange 31.

[0073] In the first and second embodiments, the material and shape of the first to fourth external electrodes 41 to 44 are not limited to the examples in each embodiment. For example, the plating layer of the first to fourth external electrodes 41 to 44 may be a single conductive layer. Alternatively, the first to fourth external electrodes 41 to 44 may not have a plating layer, and a conductive metal layer may be exposed. Alternatively, the first to fourth external electrodes 41 to 44 may be formed from a plate-shaped metal material.

[0074] In the first and second embodiments, the cross-sectional shapes of the first wire 50 and the second wire 60 are not limited to those in the above embodiments. For example, the cross-sectional shapes of the first wire 50 and the second wire 60 may be elliptical, rectangular, or the like.

[0075] In the first and second embodiments, the total number of turns of the first wire 50 and the second wire 60 is not limited to the examples of the above embodiments, as long as it is an even number of turns equal to or greater than 8. In other words, the total number of turns of the first wire 50 and the second wire 60 may be 2N turns, where N is an integer equal to or greater than 4.

[0076] In the first embodiment, at least a portion of the Nth turn in the second portion P2 may be located closer to the second flange 31 than the (N+1)th turn in the direction along the central axis C. For example, in the example shown in FIG. 4 , the first wire 50, the first portion P1 of the second wire 60, and the third portion P3 of the second wire 60 are wound in the same manner as in the first embodiment. On the other hand, when N is 5, the Nth turn of the second wire 60 is located in the valley between the (N-2)th turn and the (N-1)th turn of the second wire 60. Furthermore, at least a portion of the (N+1)th turn of the second wire 60 is located in the valley between the (N-3)th turn and the (N-2)th turn of the second wire 60. Even in such an example, the coil device 10 achieves the effects described in (1-1) of the first embodiment. 4, part of the sixth turn, specifically between the sixth and seventh turns, may ride up onto the fifth turn of the second wire 60. Even in such an example, it is sufficient that at least a part of the (N+1)th turn of the second wire 60 is located in the valley between two adjacent turns of the first portion P1.

[0077] In the first embodiment, the specific numbers of turns in the first portion P1, the second portion P2, and the third portion P3 are not limited to those in the example of the first embodiment. When N is an integer equal to or greater than 4, the first portion P1 may include the first turn through the (N-1)th turn, the second portion P2 may include the Nth turn through the (N+1)th turn, and the third portion P3 may include the (N+2)th turn through the 2Nth turn. In the first embodiment, the value of i may be an integer equal to or greater than 1 and equal to or less than N-1, and the value of j may be an integer equal to or greater than N+2 and equal to or less than 2N.

[0078] In the second embodiment, the specific numbers of turns in the first portion P1, the second portion P2, and the third portion P3 are not limited to those in the example of the second embodiment. When N is an integer equal to or greater than 4, the first portion P1 may include the second turn through the Nth turn, the second portion P2 may include the (N+1)th turn, and the third portion P3 may include the (N+2)th turn through the 2Nth turn. In the second embodiment, the value of i may be an integer between 2 and N, inclusive, and the value of j may be an integer between N+2 and 2N, inclusive.

[0079] In the second embodiment, the position at which the first turn of the second wire 60 is wound is not limited to the example of the second embodiment. For example, in the example shown in FIG. 5 , the first turn of the second wire 60 is adjacent to the first turn of the first wire 50 in the direction along the central axis C and is wound directly around the winding core 11. Furthermore, the first turn of the second wire 60 is located closer to the second flange 31 than the first turn of the first wire 50 in the direction along the central axis C. Furthermore, the first turn of the second wire 60 is located closer to the first flange 21 than the second turn of the first wire 50 in the direction along the central axis C. The first turn of the second wire 60 is continuously separated from the second turn of the first wire 50 by 0.5 turns or more. In the example shown in FIG. 5 , the first turn of the second wire 60 is continuously separated from the second turn of the first wire 50 by 0.75 turns or more. Even in such an example, the coil device 10 exhibits the effects described in (2-1) of the second embodiment.

[0080] <Supplementary Notes> The technical ideas that can be understood from the above-described embodiment and modified examples will be described below. [1] A winding core, a first flange provided at a first end of the winding core in a direction along the central axis, a second flange provided at a second end of the winding core opposite to the first end, a first external electrode and a second external electrode provided at the first flange, a third external electrode and a fourth external electrode provided at the second flange, a first wire wound around the winding core, with a first wire end connected to the first external electrode and a second wire end connected to the third external electrode, and a second wire wound around the winding core in the same direction as the first wire, with a first wire end connected to the second external electrode. and a second wire having a second wire end connected to the fourth external electrode, wherein the number of turns of the first wire and the second wire increases by one for each full turn around the central axis from the first wire end toward the second wire end, and when N is an integer equal to or greater than 4, the total number of turns of the first wire and the second wire is 2N, the first wire is wound directly around the winding core, and a first portion including the first turn to the (N-1)th turn of the second wire is wound in a direction perpendicular to the central axis. a second portion including the Nth turn to the (N+1)th turn of the second wire is wound directly from the outside of the first portion in a direction perpendicular to the central axis; a third portion including the (N+2)th turn to the 2Nth turn of the second wire is wound directly from the outside of the first wire in a direction perpendicular to the central axis; and the ith turn (where i is an integer between 1 and N-1) of the second wire belonging to the first portion is wound directly from the outside of the first wire. a coil component in which the Nth turn belonging to the second portion of the second wire is located in the valley between the (i+1)th turn and the (i+1)th turn, at least a portion of the Nth turn belonging to the second portion of the second wire is located in the valley between two adjacent turns of the first portion, at least a portion of the (N+1)th turn of the second wire is located in the valley between two adjacent turns of the first portion, and at least a portion of the jth turn (where j is an integer greater than or equal to N+2 and less than or equal to 2N) belonging to the third portion of the second wire is located in the valley between the (j-1)th turn and the jth turn of the first wire.

[0081] [2] A coil component according to [1], wherein at least a portion of the Nth turn of the second wire is located in the valley between the (N-3)th turn and the (N-2)th turn of the second wire, and at least a portion of the (N+1)th turn of the second wire is located in the valley between the (N-2)th turn and the (N-1)th turn of the second wire.

[0082] [3] A coil component according to [1], wherein at least a portion of the Nth turn of the second wire is located in the valley between the (N-2)th turn and the (N-1)th turn of the second wire, and at least a portion of the (N+1)th turn of the second wire is located in the valley between the (N-3)th turn and the (N-2)th turn of the second wire.

[0083] [4] A winding core, a first flange provided at a first end of the winding core in a direction along the central axis, a second flange provided at a second end of the winding core opposite to the first end, a first external electrode and a second external electrode provided at the first flange, a third external electrode and a fourth external electrode provided at the second flange, a first wire wound around the winding core, a first wire end connected to the first external electrode and a second wire end connected to the third external electrode, and a second wire end wound around the winding core in the same direction as the first wire, a first wire end connected to the second external electrode and a second wire end connected to the fourth external electrode. and a second wire connected to a pole, wherein the number of turns of the first wire and the second wire increases by one for each full turn around the central axis from the first wire end toward the second wire end, and when N is an integer equal to or greater than 4, the total number of turns of the first wire and the total number of turns of the second wire is 2N, the first wire is wound directly around the winding core, a first turn of the second wire is adjacent to the first turn of the first wire in a direction along the central axis and is wound directly around the winding core, and the second turn of the second wire is a first portion including the (N+1)th turn of the second wire is wound directly from the outside of the first wire in a direction perpendicular to the central axis; a second portion including the (N+1)th turn of the second wire is wound directly from the outside of the first portion in a direction perpendicular to the central axis; a third portion including the (N+2)th turn of the second wire is wound directly from the outside of the first wire in a direction perpendicular to the central axis; and at least a part of the i-th turn (where i is 2 or more and a coil component in which a jth turn (where j is an integer between N+2 and 2N) belonging to the third portion of the second wire is located between the valleys of the (j-1)th and jth turns of the first wire, and the first turn of the second wire is continuously spaced apart from the second turn of the first wire by 0.5 turns or more.

[0084] [5] The coil component according to [4], wherein the first turn of the second wire is located on the first flange side with respect to the first turn of the first wire in the direction along the central axis. [6] The coil component according to [4], wherein the first turn of the second wire is located on the second flange side with respect to the first turn of the first wire and on the first flange side with respect to the second turn of the first wire in the direction along the central axis.

[0085] C...Center axis P1...First portion P2...Second portion P3...Third portion 10...Coil component 11...Winding core portion 21...First flange portion 31...Second flange portion 41...First external electrode 42...Second external electrode 43...Third external electrode 44...Fourth external electrode 50...First wire 60...Second wire

Claims

1. A winding core; a first flange provided at a first end of the winding core in a direction along the central axis; a second flange provided at a second end of the winding core opposite the first end; first and second external electrodes provided at the first flange; a third and fourth external electrode provided at the second flange; a first wire wound around the winding core, a first wire end connected to the first external electrode and a second wire end connected to the third external electrode; and a second wire wound around the winding core in the same direction as the first wire, a first wire end connected to the second external electrode and a second wire end connected to the fourth external electrode, wherein the number of turns of the first wire and the second wire increases by one for each full rotation around the central axis from the first wire end toward the second wire end, and where N is an integer of 4 or greater, the total number of turns of the first wire and the total number of turns of the second wire is 2N, the first wire is wound directly around the winding core; a first portion including the first turn to the (N-1)th turn of the second wire is wound directly around the first wire from the outside in a direction perpendicular to the central axis; a second portion including the Nth turn to the (N+1)th turn of the second wire is wound directly around the first portion from the outside in a direction perpendicular to the central axis; a third portion including the (N+2)th turn to the 2Nth turn of the second wire is wound directly around the first wire from the outside in a direction perpendicular to the central axis; the ith turn (where i is an integer of 1 to N-1) of the second wire belonging to the first portion is located in a valley between the ith turn and the (i+1)th turn of the first wire; and at least a part of the Nth turn of the second wire belonging to the second portion is located in a valley between two adjacent turns of the first portion. A coil component in which at least a portion of the (N+1)th turn of the second wire is located in the valley between two adjacent turns of the first portion, and at least a portion of the jth turn (where j is an integer greater than or equal to N+2 and less than or equal to 2N) belonging to the third portion of the second wire is located in the valley between the (j-1)th turn and the jth turn of the first wire.

2. A coil component as described in claim 1, wherein at least a portion of the Nth turn of the second wire is located in the valley between the (N-3)th turn and the (N-2)th turn of the second wire, and at least a portion of the (N+1)th turn of the second wire is located in the valley between the (N-2)th turn and the (N-1)th turn of the second wire.

3. A coil component as set forth in claim 1 or claim 2, wherein at least a portion of the Nth turn of the second wire is located in the valley between the (N-2)th and (N-1)th turns of the second wire, and at least a portion of the (N+1)th turn of the second wire is located in the valley between the (N-3)th and (N-2)th turns of the second wire.

4. A winding core; a first flange provided at a first end of the winding core in a direction along the central axis; a second flange provided at a second end of the winding core opposite the first end; first and second external electrodes provided at the first flange; a third and fourth external electrode provided at the second flange; a first wire wound around the winding core, a first wire end connected to the first external electrode and a second wire end connected to the third external electrode; and a second wire wound around the winding core in the same direction as the first wire, a first wire end connected to the second external electrode and a second wire end connected to the fourth external electrode, wherein the number of turns of the first wire and the second wire increases by one for each full revolution around the central axis from the first wire end toward the second wire end, and when N is an integer of 4 or greater, the total number of turns of the first wire and the total number of turns of the second wire is 2N, the first wire is wound directly around the winding core; a first turn of the second wire is adjacent to the first turn of the first wire in a direction along the central axis and is wound directly around the winding core; a first portion including the second turn to the Nth turn of the second wire is wound directly around the first wire from the outside in a direction perpendicular to the central axis; a second portion including the (N+1)th turn of the second wire is wound directly around the first portion from the outside in a direction perpendicular to the central axis; a third portion including the (N+2)th turn to the 2Nth turn of the second wire is wound directly around the first wire from the outside in a direction perpendicular to the central axis; at least a portion of the i-th turn (where i is an integer between 2 and N) belonging to the first portion of the second wire is located in a valley between the i-th turn and the (i+1)th turn of the first wire; the second portion is located in a valley between two adjacent turns of the first portion in a direction perpendicular to the central axis, and at least a part of a j-th turn (where j is an integer between N+2 and 2N) of the second wire that belongs to the third portion is located in a valley between a (j-1)-th turn and a j-th turn of the first wire,A coil component in which the first turn of the second wire is continuously spaced apart from the second turn of the first wire by 0.5 turns or more.

5. A coil component according to claim 4, wherein the first turn of the second wire is located closer to the first flange portion than the first turn of the first wire in the direction along the central axis.

6. A coil component as described in claim 4 or claim 5, wherein the first turn of the second wire is located on the second flange side relative to the first turn of the first wire and on the first flange side relative to the second turn of the first wire in the direction along the central axis.

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