Common mode noise filter

Abstract

This common mode noise filter is provided with an element body and four or more conductor parts. Each of the four or more conductor parts has a spiral conductor that is a spirally wound conductor. In three or more conductor parts that are continuous in the vertical direction from among the four or more conductor parts, the number of turns of a first spiral conductor from among the spiral conductors of the three or more conductor parts is larger than the number of turns of a second spiral conductor from among the spiral conductors of the three or more conductor parts. The first spiral conductor is wound more inward than the second spiral conductor by a difference between the number of turns of the first spiral conductor and the number of turns of the second spiral conductor. In a cross section cut along the vertical direction, the innermost peripheral part of the first spiral conductor is positioned on the inside of the innermost peripheral part of the second spiral conductor.

Description

Common Mode Noise Filter

[0001] The present disclosure relates generally to a common mode noise filter, and more particularly to a common mode noise filter having multiple conductor portions.

[0002] Patent Document 1 discloses a multilayer electronic component including a main body and first and second coil portions. The main body is formed of an insulating material. The first and second coil portions are formed within the main body and are arranged in parallel in the coil axis direction. Each of the first and second coil portions has a first winding portion and a second winding portion. The first winding portion has a conductor pattern wound on an imaginary plane. The second winding portion has a conductor pattern wound parallel to the plane, is arranged in parallel to the first winding portion in the coil axis direction, and is electrically connected to the first winding portion via a through hole. In at least one of the first and second coil portions, the first and second winding portions have portions where the winding spacing of the conductor pattern is equal to each other, and these portions are offset in a direction parallel to the plane.

[0003] Japanese Patent Application Laid-Open No. 2005-294486

[0004] In the manufacturing process of a common mode noise filter such as the multilayer electronic component described in Patent Document 1, first and second coil portions (conductor portions) are formed on a main body portion (element body) by a processing method that involves heating. However, during the manufacturing process, shrinkage stress may occur inside the main body portion due to the difference in thermal shrinkage rate between the main body portion and the first and second coil portions.

[0005] A common mode noise filter according to one aspect of the present disclosure includes an element body and four or more conductor parts. The four or more conductor parts are provided inside the element body and aligned in a vertical direction. Each of the four or more conductor parts has a spiral conductor that is a spirally wound conductor. Three or more consecutive conductor parts among the four or more conductor parts in the vertical direction have different numbers of turns of the spiral conductor. In three or more consecutive conductor parts among the four or more conductor parts in the vertical direction, a first spiral conductor is wound inward by a number equal to the difference in the number of turns. The first spiral conductor is the spiral conductor of the conductor part with the relatively larger number of turns. The second spiral conductor is the spiral conductor of the conductor part with the relatively smaller number of turns. In three or more consecutive conductor parts among the four or more conductor parts in the vertical direction, an innermost circumferential portion of the first spiral conductor is located more inward than an innermost circumferential portion of the second spiral conductor in a cross section cut along the vertical direction.

[0006] The present disclosure has the advantage of being able to alleviate shrinkage stress that occurs inside the element body.

[0007] FIG. 1 is a schematic cross-sectional view of the common mode noise filter according to the first embodiment, taken along line II in FIG. 2. FIG. 2 is a projection view of a plurality of conductors in the common mode noise filter, projected onto a single plane. FIG. 3A is a plan view of a first conductor in the common mode noise filter. FIG. 3B is a plan view of a second conductor in the common mode noise filter. FIG. 3C is a plan view of a third conductor in the common mode noise filter. FIG. 3D is a plan view of a fourth conductor in the common mode noise filter. FIG. 4 is a schematic cross-sectional view of a common mode noise filter according to a comparative example. FIG. 5 is a schematic cross-sectional view of a common mode noise filter according to a second embodiment. FIG. 6A is a plan view of a first conductor in the common mode noise filter. FIG. 6B is a plan view of a second conductor in the common mode noise filter. FIG. 6C is a plan view of a third conductor in the common mode noise filter. FIG. 6D is a plan view of a fourth conductor in the common mode noise filter. Fig. 7 is a schematic cross-sectional view of the common-mode noise filter according to the third embodiment, taken along line VII-VII in Fig. 8 . Fig. 8 is a projection view of a plurality of conductor sections in the common-mode noise filter, projected onto a single plane. Fig. 9A is a plan view of a first conductor section in the common-mode noise filter. Fig. 9B is a plan view of a second conductor section in the common-mode noise filter. Fig. 9C is a plan view of a third conductor section in the common-mode noise filter. Fig. 9D is a plan view of a fourth conductor section in the common-mode noise filter. Fig. 10 is a schematic cross-sectional view of a common-mode noise filter according to a modification of the first to third embodiments, in which the spiral conductor is wound symmetrically about a center line extending in the up-down direction. Fig. 11 is a schematic cross-sectional view of a common-mode noise filter according to the modification, in which the spiral conductor of the first conductor section and the spiral conductor of the fourth conductor section have four turns, and the spiral conductor of the second conductor section and the spiral conductor of the third conductor section have five turns.Fig. 12 is a schematic cross-sectional view of a common-mode noise filter according to a modified example of the same, in which the spiral conductor of the first conductor section and the spiral conductor of the fourth conductor section have 5 turns each and the spiral conductor of the second conductor section and the spiral conductor of the third conductor section have 3 turns each. Fig. 13 is a schematic cross-sectional view of a common-mode noise filter according to a modified example of the same, in which the spiral conductor of the first conductor section and the spiral conductor of the third conductor section have 5 turns each and the spiral conductor of the second conductor section and the spiral conductor of the fourth conductor section have 3 turns each. Fig. 14 is a schematic cross-sectional view of a common-mode noise filter according to a modified example of the same, in which the spiral conductor of the first conductor section has 5 turns each, the spiral conductor of the second conductor section has 4 turns each, the spiral conductor of the third conductor section has 3 turns each, and the spiral conductor of the fourth conductor section has 2 turns. Fig. 15 is a schematic cross-sectional view of a common-mode noise filter according to a modified example of the same, in which the spiral conductor of the first conductor section has two turns, the spiral conductor of the second conductor section has four turns, the spiral conductor of the third conductor section has five turns, and the spiral conductor of the fourth conductor section has three turns. Fig. 16 is a schematic cross-sectional view of a common-mode noise filter according to a modified example of the same, in which the spiral conductor of the first conductor section has four turns, the spiral conductor of the second conductor section has three turns, the spiral conductor of the third conductor section has five turns, and the spiral conductor of the fourth conductor section has three turns. Fig. 17 is a schematic cross-sectional view of a common-mode noise filter according to a modified example of the same, in which the spiral conductor is wound asymmetrically with respect to a center line along the up-down direction.

[0008] Common mode noise filters according to embodiments 1 to 3 will be described below with reference to the drawings. However, the following embodiments 1 to 3 are merely examples of various embodiments of the present disclosure. Various modifications can be made to the following embodiments 1 to 3 depending on the design, etc., as long as the object of the present disclosure can be achieved. Furthermore, the drawings described in the following embodiments 1 to 3 are schematic diagrams, and the ratios of the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensional ratios.

[0009] (1) First Embodiment (1-1) Overview Hereinafter, an overview of a common mode noise filter 1 according to a first embodiment will be described with reference to FIGS. 1 to 4. FIG.

[0010] The common mode noise filter 1 according to the first embodiment passes differential mode components of a signal while attenuating common mode noise components. The common mode noise filter 1 is mounted on a circuit board or electronic component of an electronic device.

[0011] 1 to 3D, the common mode noise filter 1 of the first embodiment includes an element body 2 and four or more conductor portions 3. The four or more conductor portions 3 are provided inside the element body 2. The four or more conductor portions 3 are aligned in the vertical direction. Each of the four or more conductor portions 3 has a spiral conductor 31, which is a conductor wound in a spiral shape.

[0012] As shown in FIGS. 1 and 3A to 3D , among three or more conductor portions 3 that are consecutive in the vertical direction among the four or more conductor portions 3, the number of turns of the spiral conductor 31 of at least two conductor portions 3 is different from each other. In this embodiment, the number of turns of the first spiral conductor X1 among the spiral conductors 31 of the conductor portion 3 is greater than the number of turns of the second spiral conductor X2 among the spiral conductors 31 of the conductor portion 3. The first spiral conductor X1 is wound inward relative to the second spiral conductor X2 by an amount equal to the difference between the number of turns of the first spiral conductor X1 and the number of turns of the second spiral conductor X2. In this embodiment, the outermost peripheral portions of the spiral conductors X1 and X2 are aligned with each other in a top view. Furthermore, among three or more conductor portions 3 that are consecutive in the vertical direction among the four or more conductor portions 3, the innermost peripheral portion 311 of the first spiral conductor X1 is located more inward than the innermost peripheral portion 311 of the second spiral conductor X2 in a cross section cut along the vertical direction (see FIG. 1 ).

[0013] For example, the common-mode noise filter E1 according to the comparative example shown in FIG. 4 includes four conductors E3 each having a spiral conductor E31 with the same number of turns. That is, in a cross section cut vertically, the innermost circumferential portions E311 of the spiral conductors E31 in the conductors E3 are aligned vertically. In the common-mode noise filter E1 according to the comparative example, when the conductors E3 are formed in the element body E2 by a processing method involving heating, such as firing, contraction stress may occur within the element body E2 due to the difference in thermal expansion coefficient between the element body E2 and the conductors E3. This contraction stress is applied to the portion of the element body E2 located inside the innermost circumferential portion E311 of the spiral conductor E31 in each of the conductors E3. Therefore, in the common-mode noise filter E1 according to the comparative example, the innermost circumferential portions E311 of the spiral conductors E31 in the conductors E3 are aligned vertically, which presents a problem in that contraction stress is likely to occur within the element body E2 at positions where the spiral conductors E31 overlap vertically. In this case, the performance of the common mode noise filter E1 may be degraded.

[0014] In contrast, in the common-mode noise filter 1 of Embodiment 1, the innermost periphery 311 of the first spiral conductor X1 is located more inward than the innermost periphery 311 of the second spiral conductor X2. In other words, in the common-mode noise filter 1 of Embodiment 1, the innermost peripheries 311 of the spiral conductors 31 in the multiple conductor portions 3 are not aligned vertically. As a result, when the multiple conductor portions 3 are formed in the element body 2 by a processing method involving heating, such as firing, if contraction stress occurs due to a difference in the thermal expansion coefficients between the element body 2 and the multiple conductor portions 3, the positions at which the contraction stress occurs within the element body 2 are dispersed when viewed from above. In other words, the common-mode noise filter 1 of Embodiment 1 has the advantage of being able to alleviate contraction stress generated internally.

[0015] (1-2) Detailed Configuration (1-2-1) Overall Configuration Hereinafter, the detailed configuration of the common mode noise filter 1 of the first embodiment will be described with reference to FIGS. 1 to 4. FIG.

[0016] Note that the terms "up" and "down" used in this disclosure merely represent the relative positional relationship between the components of the common mode noise filter 1 and are not intended to limit the direction in which the common mode noise filter 1 is used. The common mode noise filter 1 may be used in any orientation in which "down" used in this disclosure refers to, for example, top, front, back, left, or right. Although arrows representing up / down, left / right, and front / back are shown in Figures 1 and 2, these arrows are merely used for explanatory purposes and have no substance. The up / down, left / right, and front / back directions are perpendicular to each other.

[0017] As shown in FIGS. 1 to 3D, the common mode noise filter 1 includes an element body 2 and a plurality of conductor portions 3 (four in FIG. 1).

[0018] The common-mode noise filter 1 includes a plurality of (four in FIG. 1 ) spiral conductors 41, 51, 61, and 71 included in the plurality of conductor sections 3. The spiral conductors 41, 51, 61, and 71 are arranged in pairs. More specifically, the spiral conductor 41 and the spiral conductor 61 form one pair, and the spiral conductor 51 and the spiral conductor 71 form another pair. The spiral conductors 41 and 61 are electrically connected via pad conductors 42, 52, and 62 (see FIG. 2 ), which will be described later. The spiral conductor 51 and the spiral conductor 71 are electrically connected via pad conductors 53, 63, and 72 (see FIG. 2 ), which will be described later. When the plurality of spiral conductors 41, 51, 61, and 71 are not distinguished from one another, they are also referred to as spiral conductors 31. Furthermore, when innermost circumferential portions 411, 511, 611, and 711, which will be described later, of each of the plurality of spiral conductors 41, 51, 61, and 71 are not to be distinguished from one another, they are also referred to as innermost circumferential portions 311.

[0019] The common mode noise filter 1 includes a plurality of (four in FIG. 2 ) lead conductors 43, 54, 64, and 73 as components included in the plurality of conductor sections 3. The lead conductors 43 and 64 are electrically connected via the spiral conductors 41 and 61. The lead conductors 54 and 73 are electrically connected via the spiral conductors 51 and 71.

[0020] One of the lead conductors 43 and 64 is used as a first input terminal, and the other is used as a first output terminal. One of the lead conductors 54 and 74 is used as a second input terminal, and the other is used as a second output terminal. That is, the common mode noise filter 1 has a first input terminal, a second input terminal, a first output terminal, and a second output terminal. The common mode noise filter 1 removes common mode noise from a differential signal input via the first input terminal and the second input terminal, and outputs the signal from the first output terminal and the second output terminal.

[0021] (1-2-2) Element Body As shown in Fig. 1, the element body 2 includes a plurality of (11 in Fig. 1) insulator layers 20. The plurality of insulator layers 20 are stacked in the vertical direction.

[0022] An example of the shape of the element body 2 will be described. When viewed from above, the multiple insulator layers 20 have the same shape. When viewed from above, each insulator layer 20 has a rectangular shape. When viewed from above, each insulator layer 20 has a rectangular parallelepiped shape. When the multiple insulator layers 20 are stacked, the element body 2 is formed into a rectangular parallelepiped shape as a whole.

[0023] The multiple insulator layers 20 include insulator layers 21, 22, 23, 24, 25, 26, 27, 2a, 2b, 2c, and 2d. The multiple insulator layers 20 are stacked in the following order from bottom to top: insulator layers 2a, 26, 2b, 21, 22, 23, 24, 25, 2c, 27, and 2d. Note that adjacent insulator layers 20 may be integrated to the extent that the boundaries between the layers are not visible.

[0024] The insulating layers 21 to 27 are non-magnetic layers, and may include, for example, glass ceramic as a material.

[0025] The insulator layers 2a to 2d are magnetic layers. The magnetic layers contain, for example, ferrite. For example, the thickness of the insulator layers 2a to 2d (magnetic layers) is greater than the thickness of the insulator layers 26 and 27 (non-magnetic layers) sandwiched between the insulator layers 2a to 2d.

[0026] (1-2-3) Conductor Portions As described above, the common mode noise filter 1 includes four or more conductor portions 3. In the first embodiment, the number of the four or more conductor portions 3 is four. More specifically, as shown in FIG. 1 , the common mode noise filter 1 of the first embodiment includes four conductor portions 3: a first conductor portion 4, a second conductor portion 5, a third conductor portion 6, and a fourth conductor portion 7. The four conductor portions 3 of the first embodiment are arranged vertically in the order of the first conductor portion 4, the second conductor portion 5, the third conductor portion 6, and the fourth conductor portion 7. More specifically, the four conductor portions 3 are arranged from bottom to top in the order of the first conductor portion 4, the second conductor portion 5, the third conductor portion 6, and the fourth conductor portion 7.

[0027] The first conductor 4 is provided on a first plane inside the element body 2. The second conductor 5 is provided on a second plane inside the element body 2. The third conductor 6 is provided on a third plane inside the element body 2. The fourth conductor 7 is provided on a fourth plane inside the element body 2. The first to fourth planes are aligned in the vertical direction and are parallel to each other. Note that "parallel" as used in this disclosure does not necessarily mean parallel in the strict sense, but also includes cases where there is an error of a few degrees.

[0028] The first conductor portion 4 is provided between the insulator layer 21 and the insulator layer 22. The second conductor portion 5 is provided between the insulator layer 22 and the insulator layer 23. The third conductor portion 6 is provided between the insulator layer 23 and the insulator layer 24. The fourth conductor portion 7 is provided between the insulator layer 24 and the insulator layer 25.

[0029] (First Conductor Portion) First, a description will be given of the first conductor portion 4. As shown in Fig. 3A, the first conductor portion 4 has a spiral conductor 41, a pad conductor 42, and a lead conductor 43.

[0030] The spiral conductor 41 is a conductor formed in a spiral shape, in other words, a conductor wound in a spiral shape. More specifically, the spiral conductor 41 has a shape obtained by winding a conductor multiple times around an oval (ellipse). The length of the spiral conductor 41 in the left-right direction is longer than the length of the spiral conductor 41 in the front-rear direction. The number of turns of the spiral conductor 41 in the first conductor portion 4 is 2.5 turns. In this disclosure, a "turn" is a unit of angle indicating how many times the conductor is wound, and one turn indicates that the conductor is wound one full revolution (360°). In other words, the number of turns of the spiral conductor 41 is 2.5 revolutions. In other words, the spiral conductor 41 has a shape obtained by winding a conductor 2.5 times around an oval.

[0031] The spiral conductor 41 includes a first turn portion, a second turn portion, and a third turn portion. Of these portions, the first turn portion is located on the innermost side, and the third turn portion is located on the outermost side. In other words, the first turn portion is the innermost circumferential portion 411 of the spiral conductor 41.

[0032] A first end of the spiral conductor 41 is connected to the pad conductor 42. A second end of the spiral conductor 41 is connected to the lead conductor 43.

[0033] The pad conductor 42 is disposed inside the spiral conductor 41. The pad conductor 42 has a rectangular shape with rounded corners. The pad conductor 42 of the first embodiment is disposed to the right of the center in the left-right direction. In other words, the pad conductor 42 is disposed on one side of the spiral conductor 41 in the longitudinal direction.

[0034] The lead conductor 44 is disposed outside the spiral conductor 41. More specifically, the lead conductor 44 is disposed at the outer edge of the element body 2.

[0035] (Second Conductor Section) Next, a description will be given of the second conductor section 5. As shown in Fig. 3A, the second conductor section 5 has a spiral conductor 51, pad conductors 52 and 53, and a lead conductor 54.

[0036] The spiral conductor 51 is a conductor formed in a spiral shape, in other words, a conductor wound in a spiral shape. More specifically, the spiral conductor 51 has a shape in which a conductor is wound multiple times around an oval. The length of the spiral conductor 51 in the left-right direction is longer than the length of the spiral conductor 51 in the front-rear direction. The number of turns of the spiral conductor 51 in the second conductor portion 5 is 4.5 turns. That is, the number of turns of the spiral conductor 51 is 4.5 times. In other words, the spiral conductor 51 has a shape in which a conductor is wound 4.5 times around an oval.

[0037] The spiral conductor 51 includes a first turn portion, a second turn portion, a third turn portion, a fourth turn portion, and a fifth turn portion. Of these portions, the first turn portion is located on the innermost side, and the fifth turn portion is located on the outermost side. In other words, the first turn portion is the innermost circumferential portion 511 of the spiral conductor 51.

[0038] A first end of the spiral conductor 51 is connected to the pad conductor 53. A second end of the spiral conductor 51 is connected to the lead conductor .

[0039] The pad conductors 52 and 53 are arranged inside the spiral conductor 51. The pad conductors 52 and 53 are shaped like rectangles with rounded corners. The pad conductors 52 and 53 are aligned in the left-right direction. In the first embodiment, the pad conductor 52 is arranged to the right of the center in the left-right direction, and the pad conductor 53 is arranged to the left of the center in the left-right direction. In other words, the pad conductor 52 is arranged on one side of the spiral conductor 41 in the longitudinal direction, and the pad conductor 53 is arranged on the other side of the spiral conductor 51 in the longitudinal direction. The pad conductor 52 electrically connects the pad conductor 42 of the first conductor portion 4 and the pad conductor 62 of the third conductor portion 6.

[0040] The lead conductor 54 is disposed outside the spiral conductor 51. More specifically, the lead conductor 54 is disposed at the outer edge of the element body 2.

[0041] (Third Conductor Section) Next, a description will be given of the third conductor section 6. The third conductor section 6 has a spiral conductor 61, pad conductors 62 and 63, and a lead conductor 64, as shown in FIG.

[0042] The spiral conductor 61 is a conductor formed in a spiral shape, in other words, a conductor wound in a spiral shape. More specifically, the spiral conductor 61 has a shape in which a conductor is wound multiple times around an oval. The length of the spiral conductor 61 in the left-right direction is longer than the length of the spiral conductor 61 in the front-rear direction. The number of turns of the spiral conductor 61 in the third conductor portion 6 is 4.5 turns. That is, the number of turns of the spiral conductor 61 is 4.5 times. In other words, the spiral conductor 61 has a shape in which a conductor is wound 4.5 times around an oval.

[0043] The spiral conductor 61 includes a first turn portion, a second turn portion, a third turn portion, a fourth turn portion, and a fifth turn portion. Of these portions, the first turn portion is located on the innermost side, and the fifth turn portion is located on the outermost side. In other words, the first turn portion is the innermost circumferential portion 611 of the spiral conductor 61.

[0044] A first end of the spiral conductor 61 is connected to the pad conductor 62. A second end of the spiral conductor 61 is connected to the lead conductor 64.

[0045] The pad conductors 62 and 63 are arranged inside the spiral conductor 61. The pad conductors 62 and 63 are shaped like rectangles with rounded corners. The pad conductors 62 and 63 are aligned in the left-right direction. In the first embodiment, the pad conductor 62 is arranged to the right of the center in the left-right direction, and the pad conductor 63 is arranged to the left of the center in the left-right direction. In other words, the pad conductor 62 is arranged on one side of the spiral conductor 61 in the longitudinal direction, and the pad conductor 63 is arranged on the other side of the spiral conductor 61 in the longitudinal direction. The pad conductor 63 electrically connects the pad conductor 53 of the second conductor portion 5 and the pad conductor 72 of the fourth conductor portion 7.

[0046] The lead conductor 64 is disposed outside the spiral conductor 61. More specifically, the lead conductor 64 is disposed at the outer edge of the element body 2.

[0047] (Fourth Conductor Portion) Next, a description will be given of the fourth conductor portion 7. The fourth conductor portion 7 has a spiral conductor 71, a pad conductor 72, and a lead conductor 73, as shown in FIG.

[0048] The spiral conductor 71 is a conductor formed in a spiral shape, in other words, a conductor wound in a spiral shape. More specifically, the spiral conductor 71 has a shape in which a conductor is wound multiple times around an oval. The length of the spiral conductor 71 in the left-right direction is longer than the length of the spiral conductor 71 in the front-rear direction. The number of turns of the spiral conductor 71 in the fourth conductor portion 7 is 2.5 turns. That is, the number of turns of the spiral conductor 71 is 2.5 times. In other words, the spiral conductor 71 has a shape in which a conductor is wound 2.5 times around an oval.

[0049] The spiral conductor 71 includes a first turn portion, a second turn portion, and a third turn portion. Of these portions, the first turn portion is located on the innermost side, and the third turn portion is located on the outermost side. In other words, the first turn portion is the innermost circumferential portion 711 of the spiral conductor 71.

[0050] A first end of the spiral conductor 71 is connected to the pad conductor 72. A second end of the spiral conductor 71 is connected to the lead conductor 73.

[0051] The pad conductor 72 is disposed inside the spiral conductor 71. The pad conductor 72 has a rectangular shape with rounded corners. The pad conductor 72 of the first embodiment is disposed to the left of the center in the left-right direction. In other words, the pad conductor 72 is disposed on one side of the spiral conductor 71 in the longitudinal direction.

[0052] The lead conductor 44 is disposed outside the spiral conductor 71. More specifically, the lead conductor 44 is disposed at the outer edge of the element body 2.

[0053] (Winding direction) When viewed from above, the spiral direction (winding direction) of the spiral conductor 41 in the first conductor portion 4 is opposite to the spiral direction of the spiral conductor 61 in the third conductor portion 6. When viewed from above, the spiral direction of the spiral conductor 51 in the second conductor portion 5 is opposite to the spiral direction of the spiral conductor 71 in the fourth conductor portion 7. For example, in Figures 3A to 3D, the spiral direction of the spiral conductor 41 in the first conductor portion 4 and the spiral conductor 51 in the second conductor portion 5 is counterclockwise, from the outside to the inside of the spiral. The spiral direction of the spiral conductor 61 in the third conductor portion 6 and the spiral conductor 71 in the fourth conductor portion 7 is clockwise, from the outside to the inside of the spiral.

[0054] (Difference in Number of Windings) In three or more of the four conductor portions 3 that are consecutive in the vertical direction, the number of windings of at least two of the spiral conductors 31 is different from each other. In other words, in three or more of the four conductor portions 3 that are consecutive in the vertical direction, the number of windings of at least two of the spiral conductors 31 is not the same. For example, in the first conductor portion 4, the second conductor portion 5, and the third conductor portion 6 that are consecutive in the vertical direction, the number of windings of the spiral conductor 41 is different from the number of windings of the spiral conductors 51 and 61. Furthermore, in the second conductor portion 5, the third conductor portion 6, and the fourth conductor portion 7 that are consecutive in the vertical direction, the number of windings of the spiral conductors 51 and 61 is different from the number of windings of the spiral conductor 71. In the present disclosure, as shown in FIG. 1 , the spiral conductor 31 of the conductor portion 3 that has a relatively large number of windings is referred to as the first spiral conductor X1, and the spiral conductor 31 of the conductor portion 3 that has a relatively small number of windings is referred to as the second spiral conductor X2. In the common mode noise filter 1 of the first embodiment, the first spiral conductor X1 is the spiral conductor 51 of the second conductor portion 5 and the spiral conductor 61 of the third conductor portion 6, and the second spiral conductor X2 is the spiral conductor 41 of the first conductor portion 4 and the spiral conductor 71 of the fourth conductor portion 7. In the first embodiment, the number of turns of the spiral conductors 51 and 61 of the second conductor portion 5 and the third conductor portion 6, which are the first spiral conductor X1, is two turns more than the number of turns of the spiral conductors 41 and 71 of the first conductor portion 4 and the fourth conductor portion 7, which are the second spiral conductor X2.

[0055] 1 , in three or more conductor portions 3 that are successive in the vertical direction among the four conductor portions 3, the first spiral conductor X1 is wound inward by an amount equal to the difference in the number of turns relative to the second spiral conductor X2. For example, when focusing on the first conductor portion 4, second conductor portion 5, and third conductor portion 6 that are successive in the vertical direction, the second conductor portion 5 and the third conductor portion 6 that are the first spiral conductor X1 are wound inward by two turns more than the first conductor portion 4 that is the second spiral conductor X2. Also, when focusing on the second conductor portion 5, third conductor portion 6, and fourth conductor portion 7 that are successive in the vertical direction, the second conductor portion 5 and the third conductor portion 6 that are the first spiral conductor X1 are wound inward by two turns more than the fourth conductor portion 7 that is the second spiral conductor X2.

[0056] Furthermore, in three or more conductor portions 3 that are continuous in the vertical direction among the four or more conductor portions 3, the innermost circumferential portion 311 of the first spiral conductor X1 is located more inward than the innermost circumferential portion 311 of the second spiral conductor X2 in a cross section cut along the vertical direction (see FIG. 1 ). For example, when focusing on the first conductor portion 4, the second conductor portion 5, and the third conductor portion 6 that are continuous in the vertical direction, the innermost circumferential portions 511 and 611 of the second conductor portion 5 and the third conductor portion 6, which are the first spiral conductor X1, are located more inward than the innermost circumferential portion 411 of the first conductor portion 4, which is the second spiral conductor X2, in a cross section cut along the vertical direction. Furthermore, when we look at the second conductor portion 5, the third conductor portion 6, and the fourth conductor portion 7, which are continuous in the vertical direction, in a cross section cut along the vertical direction, the innermost portions 511, 611 of the second conductor portion 5 and the third conductor portion 6, which are the first spiral conductor X1, are located more inward than the innermost portion 711 of the fourth conductor portion 7, which is the second spiral conductor X2.

[0057] The first conductor 4 has multiple (four) corner portions 412 (see FIG. 3A ), which are curved portions, and the second conductor 5 has multiple (four) corner portions 512 (see FIG. 3B ), which are curved portions. Similarly, the third conductor 6 has multiple (four) corner portions 612 (see FIG. 3C ), which are curved portions, and the fourth conductor 7 has multiple (four) corner portions 712 (see FIG. 3D ), which are curved portions. When the corner portions 412, 512, 612, and 712 are not distinguished from one another, they are also referred to as multiple corner portions 312. That is, as shown in FIGS. 3A to 3D , each of the multiple spiral conductors 31 has multiple (four) corner portions 312, which are curved portions. In other words, the first spiral conductor X1 and the second spiral conductor X2 each have multiple corner portions 312, which are curved portions. In the first embodiment, in three or more conductor portions 3 that are continuous in the vertical direction among the four or more conductor portions 3, the difference in the number of turns at each of the multiple corner portions 312 of the first spiral conductor X1 and the second spiral conductor X2 is 2 turns. In the first embodiment, when focusing on the first conductor portion 4, the second conductor portion 5, and the third conductor portion 6 that are continuous in the vertical direction, the difference in the number of turns at the corner portions 512 and 612 of the second conductor portion 5 and the third conductor portion 6 that are the first spiral conductor X1 and the corner portion 412 of the first conductor portion 4 that is the second spiral conductor X2 is 2 turns. On the other hand, when focusing on the second conductor portion 5, the third conductor portion 6, and the fourth conductor portion 7 that are continuous in the vertical direction, the difference in the number of turns at the corner portions 512 and 612 of the second conductor portion 5 and the third conductor portion 6 that are the first spiral conductor X1 and the corner portion 712 of the fourth conductor portion 7 that is the second spiral conductor X2 is 2 turns.

[0058] (1-3) Advantages In the first embodiment, it is assumed that the common mode noise filter 1 is fired during the manufacturing process. Conductors are provided on the element body 2 by electroplating, and then fired, so that the conductors become the wiring (spiral conductor 41, pad conductors 42, lead conductor 43, etc.) that constitute the conductor portion 3.

[0059] The element body 2 includes, for example, glass ceramic as a material. The conductor portion 3 includes, for example, a metal such as silver. The thermal contraction rate of the element body 2 is different from that of the conductor portion 3. Therefore, during firing, distortion may occur in the portion of the element body E2 located inside the innermost circumferential portion 311 of the spiral conductor 31 due to the difference in thermal contraction rate between the element body 2 and each of the spiral conductors 41, 51, 61, 71 and the pad conductors 42, 52, 53, 62, 63, 72. Specifically, while the element body 2 shrinks, each of the spiral conductors 41, 51, 61, 71 and the pad conductors 42, 52, 53, 62, 63, 72 expands slightly. Therefore, stress may occur between the element body 2 and each of the spiral conductors 41, 51, 61, 71 and the pad conductors 42, 52, 53, 62, 63, 72.

[0060] For example, in the common mode noise filter E1 ( FIG. 4 ) according to the comparative example, each of the plurality of conductor portions E3 has a spiral conductor E31 with the same number of turns, and in a cross section cut along the vertical direction, the innermost circumferential portions E311 of the spiral conductors E31 in the plurality of conductor portions E3 are aligned vertically. For this reason, in the common mode noise filter E1 according to the comparative example, when the plurality of conductor portions E3 are formed in the element body E2 by a processing method such as firing that involves heating, it is thought that contraction stress is likely to occur inside the element body E2 at positions where the conductor portions E3 overlap in the vertical direction.

[0061] 1 , in the common-mode noise filter 1 of Embodiment 1, in three or more conductors 3 that are continuous in the vertical direction among the four or more conductors 3, the innermost periphery 311 of the first spiral conductor X1 is located more inward than the innermost periphery 311 of the second spiral conductor X2 in a cross section taken along the vertical direction. As a result, in the common-mode noise filter 1 of Embodiment 1, when the plurality of conductors 3 are formed in the element body 2 by a processing method that involves heating, such as firing, the positions at which contraction stress occurs inside the element body 2 are dispersed in a top view. In other words, the common-mode noise filter 1 of Embodiment 1 has the advantage of being able to alleviate contraction stress that occurs inside.

[0062] Furthermore, by a processing method such as firing involving heating, shrinkage stress generated between the element body 2 and the multiple corners 312 (corners 412, 512, 612, 712) of the spiral conductor 31 (each of the spiral conductors 41, 51, 61, 71) tends to be larger than shrinkage stress generated at other locations inside the element body 2. In the common-mode noise filter 1 of Embodiment 1, in three or more conductors 3 that are consecutive in the vertical direction among the four or more conductors 3, the difference in the number of turns at each of the multiple corners 312 between the first spiral conductor X1 and the second spiral conductor X2 is two turns. As a result, in the common-mode noise filter 1 of Embodiment 1, when the multiple conductors 3 are formed in the element body 2 by a processing method such as firing involving heating, the positions where shrinkage stress occurs between the element body 2 and the multiple corners 312 of the spiral conductor 31 are dispersed in top view. That is, there is an advantage that shrinkage stress generated between the element body 2 and the multiple corners 312 of the spiral conductor 31 can be further alleviated.

[0063] (2) Second Embodiment (2-1) Overview Hereinafter, an overview of a common mode noise filter 1A according to a second embodiment will be described with reference to Fig. 5 to Fig. 6D. Components similar to those in the first embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0064] As shown in FIG. 5 , the common mode noise filter 1A of the second embodiment includes an element body 2 and four conductor portions 3A. The four conductor portions 3A are arranged inside the element body 2. The four conductor portions 3A are aligned in the vertical direction. Each of the four conductor portions 3A has a spiral conductor 31A, which is a spirally wound conductor. Among the four conductor portions 3A, three or more conductor portions 3A that are consecutive in the vertical direction have different numbers of turns of the spiral conductor 31A of at least two conductor portions 3A. The number of turns of the first spiral conductor X1, which is the spiral conductor 31A of the conductor portion 3A, is greater than the number of turns of the second spiral conductor X2, which is the spiral conductor 31A of the conductor portion 3A. The first spiral conductor X1 is wound inward more than the second spiral conductor X2 by a number equal to the difference between the number of turns of the first spiral conductor X1 and the number of turns of the second spiral conductor X2. In the embodiment, the outermost portions of the spiral conductors X1 and X2 are aligned with each other in a top view. In addition, in three or more of the four conductors 3A that are continuous in the vertical direction, the innermost portion 311A ​​of the first spiral conductor X1 is located more inward than the innermost portion 311A ​​of the second spiral conductor X2 in a cross section cut along the vertical direction.

[0065] 6A to 6D, the second embodiment differs from the first embodiment in that the difference between the number of turns of the first spiral conductor X1 and the number of turns of the second spiral conductor X2 is different. More specifically, the second embodiment differs from the first embodiment in that the number of turns of the first spiral conductor X1 is three turns more than the number of turns of the second spiral conductor X2.

[0066] (2-2) Detailed Structure As shown in Fig. 5, the four conductors 3A of the second embodiment are arranged in the vertical direction in the order of the first conductor 4A, the second conductor 5A, the third conductor 6A, and the fourth conductor 7A. More specifically, the four conductors 3A are arranged from bottom to top in the order of the first conductor 4A, the second conductor 5A, the third conductor 6A, and the fourth conductor 7A.

[0067] The configurations of the second conductor portion 5A and the third conductor portion 6A in the second embodiment are substantially the same as the configurations of the second conductor portion 5 and the third conductor portion 6 in the first embodiment. Therefore, detailed description of the second conductor portion 5A and the third conductor portion 6A will be omitted.

[0068] (First Conductor Portion) First, the first conductor portion 4 A will be described. As shown in FIG. 6A, the first conductor portion 4 A has a spiral conductor 41 A, a pad conductor 42, and a lead conductor 43.

[0069] The spiral conductor 41A is a conductor formed in a spiral shape, in other words, a conductor wound in a spiral shape. More specifically, the spiral conductor 41A has a shape in which a conductor is wound multiple times around an oval (ellipse). The length of the spiral conductor 41A in the left-right direction is longer than the length of the spiral conductor 41A in the front-rear direction. The number of turns of the spiral conductor 41 in the first conductor portion 4A is 1.5 turns. That is, the number of turns of the spiral conductor 41A is 1.5 times. In other words, the spiral conductor 41A has a shape in which a conductor is wound 1.5 times around an oval.

[0070] The spiral conductor 41A includes a first turn portion and a second turn portion. Of these portions, the first turn portion is located on the innermost side, and the second turn portion is located on the outermost side. In other words, the first turn portion of the spiral conductor 41 is the innermost peripheral portion 411A.

[0071] A first end of the spiral conductor 41A is connected to the pad conductor 42. A second end of the spiral conductor 41A is connected to the lead conductor 43.

[0072] (Fourth Conductor Section) Next, the fourth conductor section 7 A will be described. The fourth conductor section 7 A has a spiral conductor 71 A, a pad conductor 72, and a lead conductor 73, as shown in FIG.

[0073] The spiral conductor 71A is a conductor formed in a spiral shape, in other words, a conductor wound in a spiral shape. More specifically, the spiral conductor 71A has a shape in which a conductor is wound multiple times around an oval. The length of the spiral conductor 71A in the left-right direction is longer than the length of the spiral conductor 71A in the front-rear direction. The number of turns of the spiral conductor 71A in the fourth conductor portion 7A is 1.5 turns. That is, the number of turns of the spiral conductor 71A is 1.5 times. In other words, the spiral conductor 71A has a shape in which a conductor is wound 1.5 times around an oval.

[0074] The spiral conductor 71A includes a first turn portion and a second turn portion. Of these portions, the first turn portion is located on the innermost side, and the second turn portion is located on the outermost side. In other words, the first turn portion of the spiral conductor 71A is the innermost circumferential portion 711A.

[0075] A first end of the spiral conductor 71A is connected to the pad conductor 72. A second end of the spiral conductor 71A is connected to the lead conductor 73.

[0076] (Difference in Number of Windings) The number of windings of the spiral conductor 31A is different in three or more vertically consecutive conductor portions 3A among the four conductor portions 3A. In other words, the number of windings of the spiral conductor 31A is not the same in three or more vertically consecutive conductor portions 3A among the four conductor portions 3A. For example, in the first conductor portion 4A, the second conductor portion 5A, and the third conductor portion 6A, which are vertically consecutive, the number of windings of the spiral conductor 41A is different from the number of windings of the spiral conductors 51A and 61A. Furthermore, in the second conductor portion 5A, the third conductor portion 6A, and the fourth conductor portion 7A, which are vertically consecutive, the number of windings of the spiral conductors 51A and 61A is different from the number of windings of the spiral conductor 71A. 5 , the spiral conductor 31A of the conductor portion 3A having a relatively larger number of turns than the spiral conductor 31A of the conductor portion 3A is referred to as the first spiral conductor X1, and the spiral conductor 31A of the conductor portion 3A having a relatively smaller number of turns than the spiral conductor 31A of the conductor portion 3A is referred to as the second spiral conductor X2. In the common-mode noise filter 1A of the second embodiment, the first spiral conductor X1 is the spiral conductor 51A of the second conductor portion 5A and the spiral conductor 61 of the third conductor portion 6A, and the second spiral conductor X2 is the spiral conductor 41A of the first conductor portion 4A and the spiral conductor 71A of the fourth conductor portion 7A. In embodiment 2, the number of turns of the spiral conductors 51A and 61A of the second conductor portion 5A and the third conductor portion 6A, which are the first spiral conductor X1, is three turns more than the number of turns of the spiral conductors 41A and 71A of the first conductor portion 4A and the fourth conductor portion 7A, which are the second spiral conductor X2.

[0077] 5 , in three or more of the four conductor portions 3A that are consecutive in the vertical direction, the first spiral conductor X1 is wound inward more than the second spiral conductor X2 by an amount equal to the difference in the number of turns between the first spiral conductor X1 and the second spiral conductor X2. For example, when focusing on the first conductor portion 4A, the second conductor portion 5A, and the third conductor portion 6A that are consecutive in the vertical direction, the second conductor portion 5A and the third conductor portion 6A that are the first spiral conductor X1 are wound inward by three turns more than the first conductor portion 4A that is the second spiral conductor X2. Also, when focusing on the second conductor portion 5A, the third conductor portion 6A, and the fourth conductor portion 7A that are consecutive in the vertical direction, the second conductor portion 5A and the third conductor portion 6A that are the first spiral conductor X1 are wound inward by three turns more than the fourth conductor portion 7A that is the second spiral conductor X2.

[0078] Furthermore, in three or more of the four or more conductor portions 3A that are continuous in the vertical direction, the innermost circumferential portion 311A ​​of the first spiral conductor X1 is located more inward than the innermost circumferential portion 311A ​​of the second spiral conductor X2 in a cross section cut along the vertical direction (see FIG. 5 ). In the second embodiment, when attention is focused on the first conductor portion 4A, the second conductor portion 5A, and the third conductor portion 6A that are continuous in the vertical direction, the innermost circumferential portions 511A and 611A of the second conductor portion 5A and the third conductor portion 6A that are the first spiral conductor X1 are located more inward than the innermost circumferential portion 411A of the first conductor portion 4A that is the second spiral conductor X2 in a cross section cut along the vertical direction. Furthermore, when we look at the second conductor portion 5A, the third conductor portion 6A, and the fourth conductor portion 7A, which are continuous in the vertical direction, in a cross section cut along the vertical direction, the innermost portions 511A and 611A of the second conductor portion 5A and the third conductor portion 6A, which are the first spiral conductor X1, are located more inward than the innermost portion 711A of the fourth conductor portion 7A, which is the second spiral conductor X2.

[0079] The first conductor 4A has multiple (four) corner portions 412A (see FIG. 6A ), which are curved portions, and the second conductor 5A has multiple (four) corner portions 512A (see FIG. 6B ). Similarly, the third conductor 6A has multiple (four) corner portions 612A (see FIG. 6C ), which are curved portions, and the fourth conductor 7A has multiple (four) corner portions 712A (see FIG. 6D ). When the corner portions 412A, 512A, 612A, and 712A are not distinguished from one another, they are also referred to as multiple corner portions 312A. That is, as shown in FIGS. 6A to 6D , each of the multiple spiral conductors 31A has multiple (four) corner portions 312A, which are curved portions. In other words, the first spiral conductor X1 and the second spiral conductor X2 each have multiple corner portions 312A, which are curved portions. In the second embodiment, in three or more conductor portions 3A that are continuous in the vertical direction among the four or more conductor portions 3A, the difference in the number of turns at each of the multiple corner portions 312A of the first spiral conductor X1 and the second spiral conductor X2 is 3. In the second embodiment, when attention is focused on the first conductor portion 4A, the second conductor portion 5A, and the third conductor portion 6A that are continuous in the vertical direction, the difference in the number of turns at the corner portions 512A and 612A of the second conductor portion 5A and the third conductor portion 6A that are the first spiral conductor X1 and the number of turns at the corner portion 412A of the first conductor portion 4A that is the second spiral conductor X2 is 3 turns. On the other hand, when we look at the second conductor portion 5A, the third conductor portion 6A, and the fourth conductor portion 7A, which are successive in the vertical direction, the difference between the number of turns at the corner portions 512A, 612A of the second conductor portion 5A and the third conductor portion 6A, which are the first spiral conductor X1, and the number of turns at the corner portion 712A of the fourth conductor portion 7A, which is the second spiral conductor X2, is 3 turns.

[0080] 5 , in the common-mode noise filter 1A of Embodiment 2, in three or more of the four or more conductor portions 3A that are continuous in the vertical direction, the innermost periphery 311A ​​of the first spiral conductor X1 is located more inward than the innermost periphery 311A ​​of the second spiral conductor X2 in a cross section taken along the vertical direction. As a result, in the common-mode noise filter 1A of Embodiment 2, when multiple conductor portions 3A are formed in the element body 2 by a processing method that involves heating, such as firing, the positions at which contraction stress occurs inside the element body 2 are dispersed in a top view. In other words, the common-mode noise filter 1A of Embodiment 2 has the advantage of being able to alleviate contraction stress that occurs inside.

[0081] Furthermore, the distance between the innermost periphery 311A ​​of the first spiral conductor X1 and the innermost periphery 311A ​​of the second spiral conductor X2 in the common-mode noise filter 1A of Embodiment 2 is greater than the distance between the innermost periphery 311A ​​of the first spiral conductor X1 and the innermost periphery 311A ​​of the second spiral conductor X2 in the common-mode noise filter 1 of Embodiment 1. Therefore, the common-mode noise filter 1A of Embodiment 2 has the advantage of being able to more effectively alleviate contraction stress generated inside than the common-mode noise filter 1 of Embodiment 1.

[0082] Furthermore, in three or more of the four or more conductor portions 3A that are consecutive in the vertical direction, the difference in the number of turns at each of the multiple corner portions 312A of the first spiral conductor X1 and the second spiral conductor X2 is 3. As a result, in the common-mode noise filter 1A of embodiment 2, when the multiple conductor portions 3A are formed in the element body 2 by a processing method that involves heating, such as firing, the positions where contraction stress occurs between the element body 2 and the multiple corner portions 312A of the spiral conductor 31A are dispersed in top view. In other words, there is an advantage that the contraction stress occurring between the element body 2 and the multiple corner portions 312A of the spiral conductor 31A can be further alleviated.

[0083] (3) Third Embodiment (3-1) Overview Below, an overview of a common mode noise filter 1B according to a third embodiment will be described with reference to Fig. 7 to Fig. 9D. Components similar to those in the first embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0084] 7 and 8 , the common-mode noise filter 1B of the third embodiment includes an element body 2 and four conductor portions 3B. The four conductor portions 3B are provided inside the element body 2. The four conductor portions 3B are aligned in the vertical direction. Each of the four conductor portions 3B has a spiral conductor 31B, which is a spirally wound conductor. Among the four or more conductor portions 3B, three or more consecutive conductor portions 3B in the vertical direction have different numbers of turns of the spiral conductors 31B. The first spiral conductor X1, which is the spiral conductor 31B of the conductor portion 3B having a relatively larger number of turns than the second spiral conductor X2, which is the spiral conductor 31B of the conductor portion 3B, is wound inward by a number equal to the difference in the number of turns. Furthermore, in three or more of the four conductor portions 3B that are continuous in the vertical direction, in a cross section cut along the vertical direction, the innermost portion 311B of the first spiral conductor X1 is located more inward than the innermost portion 311B of the second spiral conductor X2.

[0085] 8, the third embodiment differs from the first embodiment in that the corner portions 312B (see FIG. 9C) of the spiral conductor 31B in the reference conductor Y1 (e.g., the third conductor 6B as shown in FIG. 7), which is one of the four or more conductor portions 3B, are located at different positions in a top view from the corner portions 312B (see FIGS. 9B and 9D) of the spiral conductor 31B in the adjacent conductor Y2 (e.g., the second conductor 5B and the fourth conductor 7B as shown in FIG. 7), which is the conductor portion 3B adjacent to the reference conductor Y1 in the vertical direction. In this embodiment, the outermost peripheral portions of the spiral conductors Y1 and Y2 do not coincide with each other in a top view.

[0086] (3-2) Detailed Structure As shown in Fig. 7, the four conductors 3B of the third embodiment are arranged vertically in the order of the first conductor 4B, the second conductor 5B, the third conductor 6B, and the fourth conductor 7B. More specifically, the four conductors 3 are arranged from bottom to top in the order of the first conductor 4B, the second conductor 5B, the third conductor 6B, and the fourth conductor 7B.

[0087] In the following, the description of the configurations of the first conductor portion 4B, second conductor portion 5B, third conductor portion 6B, and fourth conductor portion 7B of embodiment 3 that are similar to those of the first conductor portion 4, second conductor portion 5, third conductor portion 6, and fourth conductor portion 7 of embodiment 1 will be omitted as appropriate.

[0088] The first conductor 4B has multiple (four) curved corner portions 412B (see FIG. 9A), the second conductor 5B has multiple (four) curved corner portions 512B (see FIG. 9B), the third conductor 6B has multiple (four) curved corner portions 612B (see FIG. 9C), and the fourth conductor 7B has multiple (four) curved corner portions 712B (see FIG. 9D).

[0089] The multiple corner portions 412B of the first conductor portion 4B have the same shape as the multiple corner portions 612B of the third conductor portion 6B in top view, but have different shapes from the multiple corner portions 512B of the second conductor portion 5B and the multiple corner portions 712B of the fourth conductor portion 7B. On the other hand, the multiple corner portions 512B of the second conductor portion 5B have the same shape as the multiple corner portions 712B of the fourth conductor portion 7B in top view, but have different shapes from the multiple corner portions 412B of the first conductor portion 4B and the multiple corner portions 612B of the third conductor portion 6B. In other words, the multiple corner portions 612B of the third conductor portion 6B have the same shape as the multiple corner portions 412B of the first conductor portion 4B in top view, but have different shapes from the multiple corner portions 512B of the second conductor portion 5B and the multiple corner portions 712B of the fourth conductor portion 7B. On the other hand, the multiple corner portions 712B of the fourth conductor portion 7B have the same shape as the multiple corner portions 512B of the second conductor portion 5B in top view, but have different shapes from the multiple corner portions 412B of the first conductor portion 4B and the multiple corner portions 612B of the third conductor portion 6B. The "same shape" here refers to shapes that are curved with the same curvature, i.e., shapes with the same degree of curvature. On the other hand, the "different shapes" here refer to shapes that are curved with different curvatures, i.e., shapes with different degrees of curvature.

[0090] In the third embodiment, as shown in FIG. 8 , the corners 312B of the spiral conductor 31B in the reference conductor Y1 (see FIG. 7 ), which is one of the four conductors 3B, are positioned differently in top view from the corners 312B of the spiral conductor 31B in the adjacent conductor Y2 (see FIG. 7 ), which is the conductor 3B adjacent to the reference conductor Y1 in the vertical direction. For example, when focusing on the third conductor 6B of the four conductors 3B (assuming the reference conductor Y1 is the third conductor 6B), the corners 612B of the spiral conductor 61B in the third conductor 6B are positioned differently in top view from the corners 512B and 712B of the spiral conductors 51B and 71B in the second conductor 5B and fourth conductor 7B, which are the adjacent conductors Y2. In the present disclosure, "positioned differently in top view" means that the corners do not overlap in top view.

[0091] More specifically, the curvature of the corners 312 of the spiral conductor 31 in the reference conductor portion Y1 is different from the curvature of the corners 312 of the spiral conductor 31 in the adjacent conductor portion Y2. For example, focusing on the third conductor portion 6B among the four conductor portions 3B (assuming that the reference conductor portion Y1 is the third conductor portion 6B), the curvature of the corners 612B of the spiral conductor 61B in the third conductor portion 6B is different from the curvature of the corners 512B, 712B of the spiral conductors 51B, 71B in the second conductor portion 5B and the fourth conductor portion 7B, which are the adjacent conductor portion Y2. Specifically, the curvature of the corners 612B of the spiral conductor 61B in the third conductor portion 6B is larger than the curvature of the corners 512B, 712B of the spiral conductors 51B, 71B in the second conductor portion 5B and the fourth conductor portion 7B, which are the adjacent conductor portion Y2.

[0092] (3-3) Advantages When a processing method such as firing involving heating is used, the shrinkage stress generated between the element body 2 and the multiple corners 312B of the spiral conductor 31B tends to be larger than the shrinkage stress generated at other locations inside the element body 2. In the common-mode noise filter 1B of embodiment 3, when multiple conductors 3B are formed in the element body 2 by a processing method such as firing involving heating, the positions at which shrinkage stress occurs between the element body 2 and the multiple corners 312B of the spiral conductor 31B are more dispersed in top view. That is, there is an advantage in that the shrinkage stress generated between the element body 2 and the multiple corners 312B of the spiral conductor 31B can be further alleviated.

[0093] (4) Modifications of Embodiments 1 to 3 The above-described Embodiments 1 to 3 are merely one of various embodiments of the present disclosure. Various modifications of the above-described Embodiments 1 to 3 can be made depending on the design, etc., as long as the object of the present disclosure can be achieved. Modifications of Embodiments 1 to 3 are listed below. The following modifications may be realized in appropriate combination.

[0094] 10 , the spiral conductor 41C of the first conductor portion 4C, the spiral conductor 51C of the second conductor portion 5C, the spiral conductor 61C of the third conductor portion 6C, and the spiral conductor 71C of the fourth conductor portion 7C may be conductors wound so as to be symmetrical with respect to a center line L1 along the vertical direction in a cross section cut along the vertical direction. The center line L1 here is a line that indicates the center of the common mode noise filter 1C in a direction (front-to-back direction in the illustrated example) that intersects (here, orthogonal to) the vertical direction.

[0095] 11 , the number of turns of the spiral conductor 41D of the first conductor portion 4D and the spiral conductor 71D of the fourth conductor portion 7D may be four, and the number of turns of the spiral conductor 51D of the second conductor portion 5D and the spiral conductor 61D of the third conductor portion 6D may be five. That is, the number of turns of the spiral conductors 51D, 61D of the second conductor portion 5D and the third conductor portion 6D may be one turn more than the number of turns of the spiral conductors 41D, 71D of the first conductor portion 4D and the fourth conductor portion 7D. The spiral conductor 41D of the first conductor portion 4D, the spiral conductor 51D of the second conductor portion 5D, the spiral conductor 61D of the third conductor portion 6D, and the spiral conductor 71D of the fourth conductor portion 7D are conductors wound so as to be axisymmetrical with respect to the center line L1 along the vertical direction in a cross section cut along the vertical direction.

[0096] 12 , the number of turns of the spiral conductor 41E of the first conductor portion 4E and the spiral conductor 71E of the fourth conductor portion 7E may be five, and the number of turns of the spiral conductor 51E of the second conductor portion 5E and the spiral conductor 61E of the third conductor portion 6E may be three. That is, the number of turns of the spiral conductors 41E, 71E of the first conductor portion 4E and the fourth conductor portion 7E may be two turns more than the number of turns of the spiral conductors 51E, 61E of the second conductor portion 5E and the third conductor portion 6E. In other words, the number of turns of the spiral conductors 51E, 61E of the second conductor portion 5E and the third conductor portion 6E may be two turns less than the number of turns of the spiral conductors 41E, 71E of the first conductor portion 4E and the fourth conductor portion 7E. The spiral conductor 41E of the first conductor portion 4E, the spiral conductor 51E of the second conductor portion 5E, the spiral conductor 61E of the third conductor portion 6E, and the spiral conductor 71E of the fourth conductor portion 7E are conductors wound so as to be symmetrical with respect to the center line L1 along the vertical direction in a cross section cut along the vertical direction.

[0097] 13 , the number of turns of the spiral conductor 41F of the first conductor portion 4F and the spiral conductor 61F of the third conductor portion 6F may be five, and the number of turns of the spiral conductor 51F of the second conductor portion 5F and the spiral conductor 71F of the fourth conductor portion 7F may be three. That is, the number of turns of the spiral conductors 41F, 61F of the first conductor portion 4F and the third conductor portion 6F may be two turns more than the number of turns of the spiral conductors 51F, 71F of the second conductor portion 5F and the fourth conductor portion 7F. The spiral conductor 41F of the first conductor portion 4F, the spiral conductor 51F of the second conductor portion 5F, the spiral conductor 61F of the third conductor portion 6F, and the spiral conductor 71F of the fourth conductor portion 7F are conductors wound so as to be axisymmetrical with respect to the center line L1 along the vertical direction in a cross section cut along the vertical direction.

[0098] 14 , the spiral conductor 41G of the first conductor portion 4G may have five turns, the spiral conductor 51G of the second conductor portion 5G may have four turns, the spiral conductor 61G of the third conductor portion 6G may have three turns, and the spiral conductor 71G of the fourth conductor portion 7G may have two turns. The spiral conductors 41G, 51G, 61G, and 71G of the first conductor portion 4G, the second conductor portion 5G, the third conductor portion 6G, and the fourth conductor portion 7G may have different numbers of turns. Note that the spiral conductor 41G of the first conductor portion 4G, the spiral conductor 51G of the second conductor portion 5G, the spiral conductor 61G of the third conductor portion 6G, and the spiral conductor 71G of the fourth conductor portion 7G are wound symmetrically with respect to the center line L1 along the vertical direction in a cross section cut along the vertical direction.

[0099] Similarly, as in a common mode noise filter 1H shown in Fig. 15, the number of turns of the spiral conductor 41H of the first conductor portion 4H may be 2, the number of turns of the spiral conductor 51H of the second conductor portion 5H may be 4, the number of turns of the spiral conductor 61H of the third conductor portion 6H may be 5, and the number of turns of the spiral conductor 71H of the fourth conductor portion 7H may be 3. Also, as in a common mode noise filter 1J shown in Fig. 16, the number of turns of the spiral conductor 41J of the first conductor portion 4J may be 4, the number of turns of the spiral conductor 51J of the second conductor portion 5J may be 3, the number of turns of the spiral conductor 61J of the third conductor portion 6J may be 5, and the number of turns of the spiral conductor 71J of the fourth conductor portion 7J may be 3. The spiral conductor 41J of the first conductor portion 4J, the spiral conductor 51J of the second conductor portion 5J, the spiral conductor 61J of the third conductor portion 6J, and the spiral conductor 71J of the fourth conductor portion 7J are conductors wound so as to be symmetrical with respect to the center line L1 along the vertical direction in a cross section cut along the vertical direction.

[0100] As described above, the number of turns of the spiral conductor 31 may be different in three or more vertically consecutive conductor portions 3 among the four or more conductor portions 3, and the number of turns of the spiral conductor 31 is not limited to those in the first to third embodiments. However, in three or more vertically consecutive conductor portions 3 among the four or more conductor portions 3, the difference in the number of turns at each of the multiple corner portions 312 between the first spiral conductor X1 and the second spiral conductor X2 is preferably two turns. With this configuration, when the multiple conductor portions 3 are formed on the element body 2 by a processing method such as firing that involves heating, the positions where contraction stress occurs between the element body 2 and the multiple corner portions 312 of the spiral conductor 31 are dispersed in a top view. In other words, there is an advantage in that the contraction stress occurring between the element body 2 and the multiple corner portions 312 of the spiral conductor 31 can be alleviated.

[0101] 17 , the spiral conductor 41K of the first conductor portion 4K, the spiral conductor 51K of the second conductor portion 5K, the spiral conductor 61K of the third conductor portion 6K, and the spiral conductor 71K of the fourth conductor portion 7K may be conductors wound asymmetrically with respect to the center line L1 along the vertical direction in a cross section cut along the vertical direction. In other words, the spiral conductor 41K of the first conductor portion 4K, the spiral conductor 51K of the second conductor portion 5K, the spiral conductor 61K of the third conductor portion 6K, and the spiral conductor 71K of the fourth conductor portion 7K do not have to be conductors wound symmetrically with respect to the center line L1 along the vertical direction in a cross section cut along the vertical direction.

[0102] In the above-described first to third embodiments, the number of conductor portions 3 is four. The number of conductor portions 3 may be four or more. It is desirable that the number of conductor portions 3 is an even number.

[0103] In the above-described first to third embodiments, the spiral conductor 31 has a shape in which the conductor is wound multiple times around an oval. However, the spiral conductor 31 may have a shape in which the conductor is wound multiple times around a circle or a rectangle.

[0104] The shape of each of the pad conductors 42, 52, 53, 62, 63, and 72 is not limited to a rectangular shape with rounded corners, but may be, for example, a circular or elliptical shape.

[0105] (Summary) A common mode noise filter (1, 1A to 1K) of a first aspect includes an element body (2) and four or more conductor portions (3, 3A, 3B). The four or more conductor portions (3, 3A, 3B) are provided inside the element body (2) and are aligned in the vertical direction. Each of the four or more conductor portions (3, 3A, 3B) has a spiral conductor (31, 31A, 31B) that is a spirally wound conductor. The four or more conductor portions (3, 3A, 3B) include three or more conductor portions (3, 3A, 3B) that are continuous in the vertical direction. A first spiral conductor (X1) of the spiral conductors (31, 31A, 31B) of the three or more conductor portions (3, 3A, 3B) has a greater number of turns than a second spiral conductor (X2) of the spiral conductors (31, 31A, 31B) of the three or more conductor portions (3, 3A, 3B). The first spiral conductor (X1) is wound inwardly by a number equal to the difference between the number of turns of the first spiral conductor (X1) and the number of turns of the second spiral conductor (X2). The first spiral conductor (X1) is the spiral conductor (31, 31A, 31B) of the conductor portion (3, 3A, 3B) having a relatively large number of turns. The second spiral conductor (X2) is the spiral conductor (31, 31A, 31B) of the conductor portion (3, 3A, 3B) having a relatively small number of turns. In three or more conductor portions (3, 3A, 3B) that are continuous in the vertical direction among the four or more conductor portions (3, 3A, 3B), in a cross section cut along the vertical direction, the innermost portion (311, 311A, 311B) of the first spiral conductor (X1) is located more inward than the innermost portion (311, 311A, 311B) of the second spiral conductor (X2).

[0106] This embodiment has the advantage that it is possible to alleviate the shrinkage stress generated inside the element body (2).

[0107] In the common mode noise filter (1, 1A to 1K) of the second aspect, in the first aspect, each of the first spiral conductor (X1) and the second spiral conductor (X2) has a plurality of corner portions (312, 312A, 312B) that are curved portions. In three or more conductor portions (3, 3A, 3B) that are consecutive in the vertical direction among the four or more conductor portions (3, 3A, 3B), the difference in the number of turns at each of the plurality of corner portions (312, 312A, 312B) between the first spiral conductor (X1) and the second spiral conductor (X2) is two turns or more.

[0108] This embodiment has the advantage that it is possible to alleviate contraction stress occurring between the element body (2) and the plurality of corner portions (312, 312A, 312B) of the spiral conductor (31, 31A, 31B).

[0109] In a common mode noise filter (1, 1B) of the third aspect, in the first or second aspect, the number of the four or more conductor portions (3, 3B) is four. The four conductor portions (3, 3B) include a first conductor portion (4, 4B), a second conductor portion (5, 5B), a third conductor portion (6, 6B), and a fourth conductor portion (7, 7B) arranged in this order in the vertical direction. The number of turns of the spiral conductor (31, 31B) in each of the first conductor portion (4, 4B) and the fourth conductor portion (7, 7B) is 2.5 turns. The number of turns of the spiral conductor (31, 31B) in each of the second conductor portion (5, 5B) and the third conductor portion (6, 6B) is 4.5 turns.

[0110] This embodiment has the advantage that the shrinkage stress generated inside can be further alleviated.

[0111] In a common mode noise filter (1A) of a fourth aspect, in the first or second aspect, the number of the four or more conductor portions (3A) is four. The four conductor portions (3A) include a first conductor portion (4A), a second conductor portion (5A), a third conductor portion (6A), and a fourth conductor portion (7A) arranged in this order in the vertical direction. The number of turns of the spiral conductor (31A) in each of the first conductor portion (4A) and the fourth conductor portion (7A) is 1.5 turns. The number of turns of the spiral conductor (31A) in each of the second conductor portion (5A) and the third conductor portion (6A) is 4.5 turns.

[0112] This embodiment has the advantage that the shrinkage stress generated inside can be further alleviated.

[0113] In a common-mode noise filter (1B) of a fifth aspect, in any one of the first to fourth aspects, the spiral conductor (31B) has a plurality of corner portions (312B) that are curved portions. The plurality of corner portions (312B) of the spiral conductor (31B) in the reference conductor portion (Y1), which is any one conductor portion (3B) among the four or more conductor portions (3B), are located at different positions in a top view from the plurality of corner portions (312B) of the spiral conductor (31B) in the adjacent conductor portion (Y2), which is a conductor portion (3B) adjacent to the reference conductor portion (Y1) in the vertical direction.

[0114] This embodiment has the advantage that the contraction stress occurring between the element body (2) and the plurality of corner portions (312B) of the spiral conductor (31B) can be further alleviated.

[0115] The common mode noise filter (1B) of the sixth aspect is the fifth aspect, wherein the curvature of the multiple corner portions (312B) of the spiral conductor (31B) in the reference conductor portion (Y1) is different from the curvature of the multiple corner portions (312B) of the spiral conductor (31B) in the adjacent conductor portion (Y2).

[0116] This embodiment has the advantage that the contraction stress occurring between the element body (2) and the plurality of corner portions (312B) of the spiral conductor (31B) can be further alleviated.

[0117] 1, 1A to 1K Common mode noise filter 2 Element body 3, 3A, 3B Conductor portion 31, 31A, 31B Spiral conductor 311, 311A, 311B Innermost circumferential portion 312, 312A, 312B Corner portion 4, 4A, 4B First conductor portion 41, 41A, 41B Spiral conductor 5, 5A, 5B Second conductor portion 51, 51A, 51B Spiral conductor 6, 6A, 6B Third conductor portion 61, 61A, 61B Spiral conductor 7, 7A, 7B Fourth conductor portion 71, 71A, 71B Spiral conductor X1 First spiral conductor X2 Second spiral conductor Y1 Reference conductor portion Y2 Adjacent conductor portion

Claims

1. A common mode noise filter comprising: an element body; and four or more conductor parts provided inside the element body and arranged in a vertical direction, each of the four or more conductor parts having a spiral conductor which is a conductor wound in a spiral shape, the four or more conductor parts including three or more conductor parts which are continuous in the vertical direction and each having the spiral conductor of the four or more conductor parts, the number of turns of a first spiral conductor of the spiral conductors of the three or more conductor parts is greater than the number of turns of a second spiral conductor of the spiral conductors of the three or more conductor parts, the first spiral conductor is wound inwardly by more than the second spiral conductor by an amount equal to the difference between the number of turns of the first spiral conductor and the number of turns of the second spiral conductor, and in a cross section cut along the vertical direction, an innermost portion of the first spiral conductor is located more inside than an innermost portion of the second spiral conductor.

2. A common mode noise filter as described in claim 1, wherein each of the first spiral conductor and the second spiral conductor has a plurality of corner portions which are curved portions, and in three or more conductor portions which are consecutive in the vertical direction among the four or more conductor portions, the difference in the number of turns at each of the plurality of corner portions between the first spiral conductor and the second spiral conductor is two turns or more.

3. A common mode noise filter as described in claim 1, wherein the four or more conductor portions include a first conductor portion, a second conductor portion, a third conductor portion, and a fourth conductor portion arranged in the stated order in the vertical direction, the number of turns of the spiral conductor in each of the first conductor portion and the fourth conductor portion is 2.5 turns, and the number of turns of the spiral conductor in each of the second conductor portion and the third conductor portion is 4.5 turns.

4. A common mode noise filter as described in claim 1, wherein the four or more conductor portions include a first conductor portion, a second conductor portion, a third conductor portion, and a fourth conductor portion arranged in the stated order in the vertical direction, the number of turns of the spiral conductor in each of the first conductor portion and the fourth conductor portion is 1.5 turns, and the number of turns of the spiral conductor in each of the second conductor portion and the third conductor portion is 4.5 turns.

5. A common mode noise filter as claimed in any one of claims 1 to 4, wherein the spiral conductor has a plurality of corner portions which are curved portions, and the plurality of corner portions of the spiral conductor in a reference conductor portion which is any one of the four or more conductor portions are located at different positions in a top view from the plurality of corner portions of the spiral conductor in an adjacent conductor portion which is a conductor portion adjacent to the reference conductor portion in the up-down direction.

6. The common mode noise filter according to claim 5, wherein the curvature of the plurality of corner portions of the spiral conductor in the reference conductor portion is different from the curvature of the plurality of corner portions of the spiral conductor in the adjacent conductor portion.

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