Electronic component and circuit module

Abstract

Electronic component (10) having the following features: a core (12; 12a) comprising a winding core portion (22) extending in a first direction and a flange portion (24a) provided on one side in the first direction at an end portion of the winding core portion (22) and projecting from the winding core portion (22) to one side in a second direction perpendicular to the first direction; a first winding (16a) and a second winding (16b) wound around the winding core portion (22); and an outer electrode (14a), wherein the flange portion (24a) comprises: a flange portion main body (26a) having a first surface (S1) facing said one side in said second direction and located on said one side in said second direction compared to said winding core portion (22), and a first electrode forming portion (28a) and a second electrode forming portion (28b) projecting from the flange portion main body (26a) to one side in the second direction compared to the first surface (S1), wherein the first electrode forming portion (28a), at least a part of the first surface (S1) and the second electrode forming portion (28b) are arranged in this order from one side to the other side in a third direction perpendicular to the first direction and the second direction, wherein the first electrode forming portion (28a) has a second surface (S2a) facing the one side in the second direction, wherein the outer electrode (14a) is provided on the second surface (S2a) and is connected to the first winding (16a), wherein, when viewed from the first direction, a groove space (Sp1, Sp1a, Sp1b) is formed which is surrounded by the first electrode forming portion (28a), the second electrode forming portion (28b) and at least a part of the first surface (S1), wherein a segment (11) of the first winding (16a) between a point at which the first winding is separated from the winding core portion (22) and a point at which the first winding (16a) is brought into contact with the outer electrode (14a) is defined as a predetermined segment, wherein an end portion of the predetermined segment (11) on the one side in the third direction is located in comparison to the groove space (Sp1, Sp1a, Sp1b) on the one side in the third direction, wherein an end portion of the predetermined segment (11) on the other side in the third direction is located compared to the groove space (Sp1, Sp1a, Sp1b) on the other side in the third direction and wherein the predetermined segment (11) extends, when viewed from the first direction, toward the one side in the second direction and toward the one side in the third direction and does not include a portion overlapping the groove space (Sp1, Sp1a, Sp1b) at an entire line width of the first winding (16a), wherein the flange portion main body (26a) has a third surface (S3) facing the other side in the first direction and located between the first surface (S1) and the winding core portion (22) in the second direction, and wherein the predetermined segment (11) comprises a portion which overlaps the third surface (S3) when viewed from the first direction, wherein the third surface (S3) has a normal vector extending to the other side in the first direction and to the one side in the second direction.

Description

[0001] The present disclosure relates to an electronic component comprising a wound type coil and a circuit module.

[0002] The document US 2016 / 0 133 377 A1 discloses a coil component having a drum core comprising a first and a second flange portion with wire connecting portions and a winding core portion located between the first and the second flange portion.

[0003] As a disclosure related to an electronic component, in the related art, for example, a wound-chip type common mode choke coil disclosed in JP 2007-103596 A is known. Fig. 13 is a perspective view of a common mode choke coil 500 disclosed in JP 2007-103596 A. In Fig. 13, a direction in which a winding core portion 511 extends is defined as a front-back direction, a direction in which leg-shaped electrode portions 515a and 515b are arranged is defined as a left-right direction, and a direction perpendicular to the front-back direction and the left-right direction is defined as an up-down direction.

[0004] The common-mode choke coil 500 includes a core 510, leg-shaped electrode portions 515a and 515b, and windings 531a and 531b. The core 510 includes the winding core portion 511 and a flange portion 512. The winding core portion 511 is a prism-like member extending in the front-to-back direction. The flange portion 512 is provided at the rear end of the winding core portion 511 and protrudes in the up-down and left-right directions from the winding core portion 511. The leg-shaped electrode portions 515a and 515b are provided on the upper surface of the flange portion 512 and are arranged in the right-to-left direction in this order. A groove 513 is provided on the flange portion 512. The groove 513 is located between the leg-shaped electrode sections 515a and 515b.The lower portion of the groove 513 and the upper surface of the winding core portion 511 form a single flat surface.

[0005] The windings 531a and 531b are wound clockwise around the winding core portion 511 when viewed from the front. The winding 531a extends toward the upper right side in the groove 513 after leaving the winding core portion 511. One end of the winding 531a is connected to the leg-shaped electrode portion 515a. One end of the winding 531b is connected to the leg-shaped electrode portion 515b.

[0006] Nowadays, a resin coating for moisture protection is occasionally applied to the common-mode choke coil 500 disclosed in JP 2007-103596 A after the common-mode choke coil 500 is mounted on a circuit board. The inventor found that breakage occurred in the winding 531a when such a resin coating was applied to the common-mode choke coil 500. The inventor estimated the mechanism of occurrence of breakage in the winding as follows. Fig. 14 is a diagram illustrating a resin and the winding 531a at low temperatures. Fig. 15 is a diagram illustrating a resin and the winding 531a at high temperatures.

[0007] When a resin coating is applied to the common mode choke coil 500, a resin quickly accumulates in the groove 513. The resin accumulated in the groove 513 forms a triangular region A0 (see Fig. 13) surrounded by the upper surface of the winding core portion 511, the winding 531a, and the flange portion 512. Consequently, the winding 531a and the resin are brought into contact with each other.

[0008] When the common mode choke coil 500 is repeatedly exposed to low temperatures and high temperatures, the resin repeatedly expands and contracts. As shown in Fig. 13, the resin is present in the region A0 below the coil 531a. Therefore, when the resin contracts, the coil 531a is pulled downward by the resin and is bent so that it protrudes downward, as shown in Fig. 14. On the other hand, when the resin expands, no large force is exerted by the resin on the coil 531a because the resin becomes soft. However, the resin expands while the coil 531a remains bent, as shown in Fig. 15. The bent coil 531a is therefore buried in the expanded resin. At the time of the next contraction, the coil 531a is further pulled downward by the resin and is further bent, so that it protrudes downward. If the expansion and contraction of the resin are repeated, the amount of bending of the coil 531a gradually increases. This leads to the occurrence of a break in the coil 531a.

[0009] The object of the present invention is to provide an electronic component and a circuit module with improved characteristics capable of reducing the probability of breakage occurring in a winding.

[0010] This object is achieved by an electronic component according to claim 1 and a circuit module according to claim 5.

[0011] An electronic component according to an embodiment of the present disclosure includes a core, a first winding, a second winding, and an external electrode. The core includes a winding core portion extending in a first direction, and a flange portion provided at one end portion of the winding core portion on one side in the first direction and projecting from the winding core portion toward one side in a second direction perpendicular to the first direction. The first winding and a second winding are wound around the winding core portion.The flange portion includes a flange portion main body having a first surface facing a side in the second direction and located on one side in the second direction compared to the winding core portion, and first and second electrode formation portions protruding from the flange portion main body to one side in the second direction compared to the first surface. The first electrode formation portion, at least a part of the first surface, and the second electrode formation portion are arranged in this order from one side to the other side in a third direction perpendicular to the first direction and the second direction. The first electrode formation portion has a second surface facing a side in the second direction. The outer electrode is provided on the second surface and is connected to the first winding.When viewed from the first direction, a groove space is formed, which is surrounded by the first electrode formation portion, the second electrode formation portion, and at least a part of the first surface. A segment of the first winding between a point where the first winding is separated from the winding core portion and a point where the first winding is brought into contact with the outer electrode is defined as a predetermined segment. An end portion of the predetermined segment on one side in the third direction is located compared to the groove space on one side in the third direction. An end portion of the predetermined segment on the other side in the third direction is located compared to the groove space on the other side in the third direction.When viewed from the first direction, the predetermined segment extends to one side in the second direction and to one side in the third direction and does not include a portion that overlaps the groove space at an entire line width of the first winding. The flange portion main body has a third surface that faces the other side in the first direction and is located between the first surface and the winding core portion in the second direction. The predetermined segment includes a portion that overlaps the third surface when viewed from the first direction. The third surface has a normal vector that extends to the other side in the first direction and to the one side in the second direction.

[0012] A circuit module according to an embodiment of the present disclosure includes the above-described electronic component, a circuit board including a board main body having a first main surface and a pad electrode provided on the first main surface, and a coating resin. The outer electrode is electrically connected to the pad electrode. The coating resin covers at least a portion of a surface of the electronic component.

[0013] The phrase "the normal vector of a surface extends toward one side (or the other side) in a predetermined direction" used herein means that the normal vector of the surface is parallel to the predetermined direction. The phrase "the normal vector of the surface is parallel to the predetermined direction" means that the normal vector of the surface may be parallel to the predetermined direction or may deviate slightly from such a parallel state due to manufacturing variations. The phrase "a surface faces one side (or the other side) in a predetermined direction" means that the normal vector of the surface may be parallel to the predetermined direction or may be inclined with respect to the predetermined direction.

[0014] According to an embodiment of the present disclosure, the probability of breakage occurring in a winding may be reduced.

[0015] Preferred embodiments of the present invention and other features, elements, characteristics, and advantages of the present disclosure will become apparent from the following detailed description with reference to the attached drawings. Fig. 1 an external perspective view of an electronic component; Fig. 2 a plan view of a core in the electronic component when viewed from a bottom side; Fig. 3 a plan view of the core in the electronic component when viewed from a top side; Fig. 4 a cross-sectional structural diagram of the core along a line AA, which in Fig. 2 is illustrated; Fig. 5 is a cross-sectional structural diagram of a circuit module; Fig. 6 is a cross-sectional structural diagram of a core in an electronic component which is a modification; Fig. 7 is a cross-sectional structural diagram of a core in an electronic component which is a comparative example; Fig. 8 is a plan view of a groove space which is a first reference, as viewed from a front side; Fig. 9 is a plan view of a groove space which is a second reference, as viewed from the front side; Fig. 10 is a diagram illustrating the size of each section in first to third specimens; Fig. 11 is a plan view of a core when viewed from the bottom; Fig. 12 is a plan view of the core when viewed from the top; Fig. 13 is a perspective view of a common mode choke coil disclosed in JP 2007-103596 A; Fig. 14 is a diagram illustrating a resin and a winding at low temperatures; and Fig. 15 is a diagram illustrating the resin and winding at high temperatures. (Examples of implementation)

[0016] An electronic component according to an embodiment of the present disclosure and a circuit module according to an embodiment of the present disclosure will be described below with reference to the attached drawings. Fig. 1 is an external perspective view of an electronic component 10. Fig. 2 is a plan view of a core 12 in the electronic component 10 when viewed from a bottom side. Fig. 3 is a plan view of the core 12 in the electronic component 10 when viewed from a top side. Fig. Figure 4 is a cross-sectional structural diagram of the core along a line AA shown in Fig. 2 is illustrated. In Fig. 4, a segment I1 is illustrated between a point where the winding 16a is separated from a winding core portion 22 and a point where the winding 16a is brought into contact with an outer electrode 14a, and the illustration of the other portion of the winding 16a is omitted.

[0017] Hereinafter, a direction in which the winding core portion 22 of the core 12 extends in the electronic component 10 is defined as a front-back direction (the front-back direction is an example of a first direction, a back side is an example of one side, and a front side is an example of the other side). A direction in which the outer electrode 14a and an outer electrode 14b are arranged is defined as a left-right direction (the left-right direction is an example of a third direction, a right side is an example of one side, and a left side is an example of the other side). The front-back direction and the left-right direction are perpendicular to each other.A direction perpendicular to the front-back direction and the left-right direction is defined as an up-down direction (the up-down direction is an example of a second direction, a top side is an example of one side, and a bottom side is an example of the other side). The front-back direction, the left-right direction, and the up-down direction are directions defined for describing the electronic component 10 and do not have to correspond to a front-back direction, a left-right direction, or a up-down direction, respectively, when the electronic component 10 is used.

[0018] As in Fig. As illustrated in Figure 1, the electronic component 10 includes the core 12, external electrodes 14a to 14d, windings 16a and 16b, and a top plate 18. The core 12 is made of a magnetic material such as Ni-Zn ferrite. A material for the core 12 is not limited to Ni-Zn ferrite and may be another material. As shown in Fig. 1 to 3, the core 12 includes the winding core portion 22 and the flange portions 24a and 24b.

[0019] As in Fig. 2, the winding core portion 22 has a substantially quadrangular columnar shape extending in the front-to-back direction. In this embodiment, the winding core portion 22 has an upper surface, a lower surface, a right surface, and a left surface. The upper surface has a normal vector extending toward the upper surface. The lower surface has a normal vector extending toward the lower surface. The right surface has a normal vector extending toward the right side. The left surface has a normal vector extending toward the left side. The winding core portion 22 does not necessarily have to have a substantially quadrangular columnar shape and may have another shape such as a substantially cylindrical columnar shape.

[0020] The flange portion 24a is provided at the rear end of the winding core portion 22 and protrudes from the winding core portion 22 toward the top, bottom, right side, and left side. The flange portion 24a is a plate-shaped member having a substantially rectangular main surface when viewed from the front. The long sides of the flange portion 24a at the top and bottom are parallel to the left-right direction, and the short sides of the flange portion 24a at the right and left sides are parallel to the up-down direction when viewed from the front.

[0021] The boundary between the winding core portion 22 and the flange portion 24a is described. As in Fig. 2, the windings 16a and 16b to be described below are wound around the winding core portion 22. In this embodiment, the cross-sectional shape of the winding core portion 22, which is vertical to the front-back direction, is substantially uniform. The portion extending in the up-down direction and the left-right direction from the winding core portion 22 to the flange portion 24a is not considered as a part of the winding core portion 22, but as a part of the flange portion 24a, because the windings 16a and 16b are not wound around the portion and the cross-sectional shape of the portion is not substantially uniform.

[0022] The flange portion 24a includes a flange main body 26a and electrode formation portions 28a and 28b. The flange main body 26a is a different portion than the electrode formation portions 28a and 28b described below for the flange portion 24a. The flange main body 26a has surfaces S1 and S3. Surface S1 (an example of a first surface) is the upper surface of the flange main body 26a and faces the upper side. Surface S1 lies above the winding core portion 22. In this embodiment, surface S1 has a normal vector extending toward the upper side. The surface S1 includes a portion extending in the front-back direction between the electrode formation portions 28a and 28b to be described below and a portion extending in the left-right direction at the front of the electrode formation portions 28a and 28b, and is substantially T-shaped.The normal vector of the surface S1 may extend to the inclined upper side (for example, an upper front side or an upper back side).

[0023] The surface S3 (an example of a third surface) faces the front side and is located in the up-down direction between the surface S1 and the winding core portion 22. In this embodiment, the surface S3 has a normal vector extending toward the upper front side. The surface S3 is a part of the front surface of the flange main body 26a, and more specifically, is a substantially rectangular surface connecting the upper surface of the winding core portion 22 and the surface S1. The long side of the surface S3 on the lower side is therefore in contact with the winding core portion 22. The long side of the surface S3 on the upper side is in contact with the surface S1. The surface S3 may have a normal vector extending toward the front side.

[0024] The electrode forming portions 28a and 28b are portions that protrude from the surface S1 of the flange main body 26a to the upper side. The electrode forming portions 28a and 28b are therefore located above the surface S1 of the flange portion 24a. Referring to Fig. 4, the electrode formation portions 28a and 28b are portions above a dotted line in the flange portion 24a. The electrode formation portion 28a, a part of the surface S1, and the electrode formation portion 28b are arranged from the right side to the left side in this order. The shapes of the electrode formation portions 28a and 28b will be described in more detail below.

[0025] The electrode formation portion 28a (an example of a first electrode formation portion) has a surface S2a (an example of a second surface) facing the top surface. In this embodiment, the surface S2a has a normal vector extending toward the top surface. The surface S2a is substantially L-shaped when viewed from the top surface. More specifically, the surface S2a includes a main portion 30a and a protrusion portion 32a, as shown in Fig. 3. The main portion 30a has a substantially rectangular shape with long sides extending in the left-right direction. The protruding portion 32a protrudes from the right end of the main portion 30a toward the front side. The main portion 30a may have a shape other than a rectangular one under the condition that it extends in the left-right direction. The protruding portion 32a may protrude from a position on the right side of the left end of the main portion 30a toward the front side. Accordingly, the protruding portion 32a may protrude from a position other than the right end of the main portion 30a toward the front side.

[0026] The electrode formation portion 28a has a surface S4 (an example of a fourth surface) facing the left side. In this embodiment, the surface S4 has a normal vector extending toward the upper left side. The surface S4 is the left surface of the electrode formation portion 28a and is a substantially rectangular surface connecting the surfaces S1 and S2a. In this embodiment, the surface S4 (an example of the fourth surface) is inclined with respect to the surface S2a (an example of the second surface). However, the surface S4 may have a normal vector extending toward the left side, that is, may be vertical to the surface S2a.

[0027] The electrode formation portion 28b (an example of a second electrode formation portion) has a surface S2b facing the top surface. In this embodiment, the surface S2b has a normal vector extending toward the top surface. The surface S2b is substantially L-shaped when viewed from the top surface. More specifically, the surface S2b includes a main portion 30b and a protrusion portion 32b, as shown in Fig. 3. The main portion 30b has a substantially rectangular shape with long sides extending in the left-right direction. The protruding portion 32b protrudes from the left end of the main portion 30b toward the front side. The main portion 30b may have a shape other than a rectangular one under the condition that it extends in the left-right direction. The protruding portion 32b may protrude from a position on the left side of the right end of the main portion 30b toward the front side. Accordingly, the protruding portion 32b may protrude from a position other than the left end of the main portion 30b toward the front side.

[0028] The electrode formation portion 28b has a surface S5 (an example of a fifth surface) facing the right side. In this embodiment, the surface S5 has a normal vector extending toward the upper right side. The surface S5 is the right surface of the electrode formation portion 28b and is a substantially rectangular surface connecting the surfaces S1 and S2b. In this embodiment, the surface S5 (an example of the fifth surface) is inclined with respect to the surface S2b (an example of the second surface). However, the surface S5 may have a normal vector extending toward the right side, that is, vertical to the surface S2b.

[0029] In the flange portion 24a described above, the groove space Sp1 is formed as shown in Fig. 4. The groove space Sp1 is surrounded by the electrode formation portions 28a and 28b and the surface S1 when viewed from the front side. In this embodiment, the groove space Sp1 is a substantially trapezoidal space surrounded by the surfaces S1, S4, and S5 when viewed from the front side. The groove space Sp1 opens at the top, the front side, and the back side. The front surface of the groove space Sp1 is a plane connecting the front side of the surface S4 and the front side of the surface S5. The back surface of the groove space Sp1 is a plane connecting the back side of the surface S4 and the back side of the surface S5. The top surface of the groove space Sp1 is a plane connecting the top side of the surface S4 and the top side of the surface S5.

[0030] The outer electrode 14a is provided on the surface S2a. Specifically, the outer electrode 14a covers the entire surface of the surface S2a to span the main portion 30a and the protrusion portion 32a of the surface S2a.

[0031] The outer electrode 14b is provided on the surface S2b. Specifically, the outer electrode 14b covers the entire surface of the surface S2b, covering the main portion 30b and the protrusion portion 32b of the surface S2b. The above-described outer electrodes 14a and 14b are formed by applying Ni plating and Sn plating to a base electrode made of Ag. Other materials may be used for the outer electrodes 14a and 14b.

[0032] The flange portion 24b is provided at the front end of the winding core portion 22 and protrudes from the winding core portion 22 to the top, bottom, right side, and left side. The structure of the flange portion 24b has a rotationally symmetrical relationship to the structure of the flange portion 24a with respect to an axis Ax (see Fig. 2) passing through the center of the winding core portion 22 (an intersection of diagonal lines) and extending in the up-down direction when viewed from the top side. Therefore, the description of the structure of the flange portion 24b is omitted.

[0033] External electrodes 14c and 14d are provided on surfaces S2c and S2d, respectively. The structures of the external electrodes 14c and 14d have a rotationally symmetric relationship to the structures of the external electrodes 14a and 14b with respect to the axis Ax (see Fig. 2). The descriptions of the structures of the external electrodes 14c and 14d are therefore omitted.

[0034] The windings 16a and 16b are wound around the winding core section 22, as shown in Fig. 1. More specifically, the windings 16a and 16b (examples of the first winding and the second winding) extend from the front to the rear when viewed from the front side while being wound clockwise to form a helical shape. The windings 16a and 16b extend parallel to each other around the winding core portion 22 so that they are aligned in the front-to-rear direction. The winding 16a and the winding 16b are therefore arranged alternately in the front-to-rear direction on the surface of the winding core portion 22. After the winding 16a is wound around the winding core portion 22, the winding 16b can be wound onto the winding 16a. Alternatively, after the winding 16b has been wound around the winding core portion 22, the winding 16a may be wound onto the winding 16b.A coil formed by winding 16a and a coil formed by winding 16b are magnetically coupled to each other, forming a common-mode choke coil. These coils can form a transformer. The windings 16a and 16b are formed by coating a metal wire, made of Cu, for example, with an insulating resin, made of synthetic resin varnish, for example. The diameters of the windings 16a and 16b are approximately 0.05 mm, for example.

[0035] A rear end t1 (an example of an end portion) is connected to the outer electrode 14a. A front end t2 of the coil 16a is connected to the outer electrode 14d. A rear end t3 of the coil 16b is connected to the outer electrode 14b. A front end t4 of the coil 16b is connected to the outer electrode 14c. The rear ends t1 and t3 and the front ends t2 and t4 are connected to the outer electrodes 14a, 14b, 14d, and 14c, respectively, by thermocompression bonding. More specifically, the rear ends t1 and t3 and the front ends t2 and t4 are pressed against the outer electrodes 14a, 14b, 14d, and 14c, respectively, by a heating tool. Consequently, the coatings of the rear ends t1 and t3 and the front ends t2 and t4 are melted, metal wires are exposed, and the respective metal wires are connected to the external electrodes 14a to 14d.

[0036] In the electronic component 10, in order to reduce the probability of breakage occurring in the winding 16a, the positional relationship between the winding 16a and the groove space Sp1 is developed. The positional relationship between the winding 16a and the groove space Sp1 will be described below with reference to Fig. 1 to 4. A segment between a point where the winding 16a is separated from the winding core portion 22 and a point where the winding 16a is brought into contact with an outer electrode 14b is defined as the segment 11 (an example of a predetermined segment).

[0037] The width of the winding core portion 22 in the left-right direction is larger than that of the groove space Sp1 in the left-right direction. The winding 16a is separated from the winding core portion 22 at the upper left corner, as shown in the cross-sectional view in Fig. 4. Therefore, the position where the winding 16a is separated from the winding core portion 22 (i.e., the left end of the segment 11) is located on the left side of the groove space Sp1. The outer electrode 14a is located on the right side of the groove space Sp1. The position where the winding 16a is brought into contact with the outer electrode 14a (i.e., the right end of the segment 11) is located on the right side of the groove space Sp1. The right end of the segment 11 is above the left end of the segment 11. Therefore, the segment 11 extends from the lower left side to the upper right side when viewed from the front side. The segment 11 includes a portion that overlaps the surface S3 when viewed from the front side and also extends from the lower left side to the upper right side on the surface S3.

[0038] In the electronic component 10, the segment 11 overlaps when viewed from the front, as in Fig. 4, but not the groove space Sp1. Specifically, while the segment 11 extends from the lower left side to the upper right side so as to straddle the surface S3, the segment 11 extends from the left side to the right side below the groove space Sp1 when viewed from the front. After straddle the surface S3, the segment 11 further extends from the lower left side to the upper right side when viewed from the front so as to reach the outer electrode 14a. The segment 11 straddle the outer electrode 14a from a position near a corner formed by the main portion 30a and the protrusion portion 32a.

[0039] The positional relationship between the winding 16b and the groove space Sp2 has a rotationally symmetrical relationship to the positional relationship between the winding 16a and the groove space Sp1 with respect to the axis Ax. Therefore, detailed descriptions of the positional relationship between the winding 16b and the groove space Sp2 are omitted.

[0040] The top plate 18 is a substantially rectangular plate-shaped member when viewed from the top. The top plate 18 is made of a magnetic material such as Ni-Zn ferrite. A material for the top plate is not limited to Ni-Zn ferrite and may be another material. The top plate 18 is bonded to the lower surfaces of the flange portions 24a and 24b using an adhesive (for example, a thermosetting epoxy resin). Accordingly, a closed magnetic circuit is formed by the winding core portion 22, the flange portion 24a, the top plate 18, and the flange portion 24b. The electronic component 10 does not necessarily need to include the top plate 18.

[0041] The length of the electronic component 10 with the above-described configuration in the front-back direction is, for example, approximately 3.2 mm. The width of the electronic component 10 in the left-right direction is, for example, approximately 2.5 mm. The height of the electronic component 10 in the top-bottom direction is, for example, approximately 2.5 mm. The size of the electronic component 10 is not limited to the size described above.

[0042] The electronic component 10 is arranged on a circuit board. A circuit module comprising the electronic component 10 and a circuit board will be described below with reference to the attached drawings. Fig. 5 is a cross-sectional structural diagram of a circuit module 100. In Fig. However, Figure 5 only illustrates the cross section of a coating resin 108. Regarding the electronic component 10 and a circuit board 102, Fig. 5 shows the side view of the same. The position of the cross section of the coating resin 108 is the center of the electronic component 10 in the left-right direction.

[0043] The circuit module 100 includes the electronic component 10, the circuit board 102, and the coating resin 108. The circuit board 102 includes a board main body 104 and pad electrodes 106a to 106d (the pad electrodes 106a and 106d are not illustrated). The board main body 104 is, for example, a plate-like multilayer substrate and has an upper surface (an example of a first main surface) and a lower surface. The pad electrodes 106a to 106d are provided on the upper surface of the board main body 104.

[0044] The outer electrodes 14a to 14d are electrically connected to the pad electrodes 106a to 106d using solder or an electroconductive adhesive, respectively. Consequently, the electronic component 10 is mounted on the circuit board 102. The coating resin 108 covers the entire electronic component 10 for moisture protection. The coating resin 108 covering the electronic component 10, which is located in Fig. 5, is formed by dripping a liquid resin onto the electronic component 10. A material for the coating resin 108 is, for example, a polyolefin resin, which is made of polyethylene, for example. The coating resin 108 can cover the electronic component 10 entirely or partially. The coating resin 108 does not necessarily have to be formed by dripping a liquid resin onto the electronic component 10 and can be applied to the electronic component 10, for example, by spraying. (Effects)

[0045] By using the electronic component 10 with the above-described configuration, the probability of breakage occurring in the windings 16a and 16b can be reduced. Since the same principle of reducing the probability of breakage occurring in a winding can be established for the windings 16a and 16b, the description of this principle will be made using the winding 16a as an example.

[0046] In the electronic component 10, the segment 11 does not overlap the groove space Sp1 when viewed from the front. The coating resin 108 accumulated in the groove space Sp1 hardly comes into contact with the segment 11. Therefore, even if the electronic component 10 is repeatedly exposed to low temperatures and high temperatures, the segment 11 is hardly pulled into the groove space Sp1 on the rear side by the coating resin 108 accumulated in the groove space Sp1. Consequently, the probability of breakage in the winding 16a can be reduced.

[0047] In electronic component 10, segment I1 may slightly overlap groove space Sp1 when viewed from the front. The positional relationship between segment I1 and groove space Sp1 is described below. Fig. 6 is a cross-sectional structural diagram of a core in an electronic component which is a modification. Fig. 7 is a cross-sectional structural diagram of a core in an electronic component which is a comparative example.

[0048] As in Fig. 6, a portion of the line width of the winding 16a may overlap the groove space Sp1 when viewed from the front. Referring to Fig. 6, a portion of half the line width of segment 11 overlaps the groove space Sp1 when viewed from the front. In this case, the coating resin 108 accumulated in the groove space Sp1 easily comes into contact with segment 11. Since the amount of coating resin 108 in contact with segment 11 is small, a force applied to segment 11 is also small. Therefore, the probability of breakage occurring in winding 16a can be reduced.

[0049] Furthermore, in the electronic component, which is a modification, the segment I1 partially overlaps the surface S3 when viewed from the front side. Even if the segment I1 is pulled into the groove space Sp1 on the rear side by the coating resin 108, the segment I1 is held firmly by the surface S3. Consequently, the segment I1 can be prevented from being excessively bent after pulling. This can reduce the likelihood of breakage occurring in the winding 16a.

[0050] However, the entire line width of the winding 16a must not overlap the groove space Sp1 when viewed from the front. More specifically, with reference to Fig. 7, the entire line width of the winding 16a when viewed from the front overlaps the groove space Sp1. That is, the segment 11 includes a portion whose entire line width when viewed from the front overlaps the groove space Sp1. In this case, a large amount of the coating resin 108 accumulated in the groove space Sp1 comes into contact with the segment 11. A force added to the segment 11 by the coating resin 108 accumulated in the groove space Sp1 is also large. Accordingly, in an electronic component having the Fig. 7, a break may occur in the winding 16a.

[0051] In the electronic component, which is a comparative example, a triangular space is formed by the segment I1 and the surfaces S1 and S4 when viewed from the front. In this triangular space, the coating resin 108 forms a film. If such an electronic component is repeatedly exposed to low temperatures and high temperatures, the film of the coating resin 108 repeatedly contracts and expands. When the film of the coating resin 108 contracts, the segment I1 is pulled downward by the film of the coating resin 108 and bent so that it protrudes downward. On the other hand, when the film of the coating resin 108 expands, no large force is exerted by the film of the coating resin 108 on the segment I1 because the film of the coating resin 108 becomes soft. However, the film of the coating resin 108 expands while the segment I1 remains bent.The bent segment 11 is therefore buried in the expanded film of the coating resin 108. At the time of the next contraction, the segment 11 is further pulled downward by the film of the coating resin 108 and is further bent so that it protrudes downward. In a case where the expansion and contraction of the film of the coating resin 108 are repeated, the bending amount of the segment 11 gradually increases. This leads to the occurrence of a break in the winding 16a. For this reason, the entire line width of the segment 11 of the winding 16a, when viewed from the front side, must not overlap the groove space Sp1, as in the electronic component 10 and the electronic component that is a modification.

[0052] By using the electronic component 10, the probability of breakage occurring in the windings 16a and 16b can be reduced for the following reason. Since the same principle of reducing the probability of breakage occurring in a winding can be established for the windings 16a and 16b, the description of this principle will be made using the winding 16a as an example.

[0053] In the electronic component 10, the segment I1 extends toward the upper rear side. Therefore, when the surface S3 has a normal vector extending toward the upper front side, the segment I1 and the surface S3 easily come into line contact with each other. Therefore, even if the segment I1 is pulled toward the rear side by the coating resin 108, the segment I1 is held firmly by the surface S3. Since the segment I1 and the surface S3 are in line contact, a force added by the surface S3 is dispersed over a wide part of the segment I1. Consequently, the probability of breakage occurring in the winding 16a can be reduced.

[0054] By using the electronic component 10, both the probability of a break occurring in the winding 16a and the probability of a short circuit occurring between the outer electrodes 14a and 14b can be reduced. Fig. 8 is a plan view of a groove space, which is a first reference, when viewed from a front side. Fig. 9 is a plan view of a groove space Sp1b, which is a second reference, when viewed from the front side. Fig. Figure 8 illustrates the groove spaces Sp1a and Sp1 overlapping each other. Fig. Figure 9 illustrates the groove spaces Sp1b and Sp1, which overlap each other. Fig. 8 and Fig. In Figure 9, the groove space Sp1 is represented by a dotted line. Both the groove space Sp1a, which is the first reference, and the groove space Sp1b, which is the second reference, are used to describe effects and are embodiments of the present disclosure.

[0055] More precisely, the Fig. The groove space Sp1a illustrated in Figure 8 has a substantially rectangular shape when viewed from the front. The width of the groove space Sp1a in the left-right direction is the same as the width of the upper surface of the groove space Sp1 in the left-right direction. Therefore, the distance between the outer electrodes 14a and 14b becomes long, and the probability of a short circuit occurring between the outer electrodes 14a and 14b can be reduced.

[0056] However, the area of ​​the groove space Sp1a is larger than that of the groove space Sp1. The amount of resin accumulated in the groove space Sp1a is larger than the amount accumulated in the groove space Sp1. The probability that the resin accumulated in the groove space Sp1a comes into contact with the segment I1 is greater than the probability that the resin accumulated in the groove space Sp1 comes into contact with the segment I1. Accordingly, the probability of breakage occurring in the winding 16a is higher in an electronic component using the groove space Sp1a than in the electronic component 10 using the groove space Sp1.

[0057] On the other hand, the Fig. 9 has a substantially rectangular shape when viewed from the front. The width of the groove space Sp1b in the left-right direction is the same as the width of the bottom surface (surface S1) of the groove space Sp1 in the left-right direction. Therefore, the area of ​​the groove space Sp1b becomes small, and the probability of breakage occurring in the winding 16a can be reduced.

[0058] However, the distance between the outer electrodes 14a and 14b is shorter in an electronic component using the groove space Sp1b than in the electronic component 10 using the groove space Sp1. Accordingly, the probability of a short circuit occurring between the outer electrodes 14a and 14b is higher in an electronic component using the groove space Sp1b than in the electronic component 10 using the groove space Sp1.

[0059] Thus, by using the groove spaces Sp1a and Sp1b, which have a substantially rectangular shape when viewed from the front, it is difficult to reduce both the probability of a breakage occurring in the winding 16a and the probability of a short circuit occurring between the outer electrodes 14a and 14b.

[0060] In the electronic component 10, the surface S4 has a normal vector extending toward the upper left side, and the surface S5 has a normal vector extending toward the upper right side. Therefore, the area of ​​the groove space Sp1 can be reduced while the distance between the outer electrodes 14a and 14b is increased. Consequently, in the electronic component 10, both the probability of a breakage occurring in the winding 16a and the probability of a short circuit occurring between the outer electrodes 14a and 14b can be reduced. For the same reason, in the electronic component 10, both the probability of a breakage occurring in the winding 16b and the probability of a short circuit occurring between the outer electrodes 14c and 14d can be reduced.

[0061] The surface S4 may have a normal vector extending toward the upper left side, and the surface S5 may have a normal vector extending toward the right side. Alternatively, the surface S4 may have a normal vector extending toward the left side, and the surface S5 may have a normal vector extending toward the upper right side. In a case where neither the probability of breakage in the winding 16a nor the probability of short circuiting between the outer electrodes 14a and 14b needs to be reduced, the groove space Sp1a or Sp1b having a substantially rectangular shape when viewed from the front side may be used in an electronic component.

[0062] By using the electronic component 10, the probability of breakage occurring in the windings 16a and 16b can also be reduced for the following reason. Since the same principle of reducing the probability of breakage occurring in a winding can be established for the windings 16a and 16b, the description of this principle will be made using the winding 16a as an example. In the electronic component 10, the winding 16a in the segment 11 extends linearly from the lower left side to the upper right side along the surface S3. Since the flange portion 24a has the surface S3 connected to the winding core portion 22 and is inclined with respect to the winding core portion 22, the winding 16a in the segment 11 can be in surface contact with the flange portion 24a without being bent.Therefore, the probability of a breakage occurring in the winding 16a during manufacturing can be reduced.

[0063] Furthermore, the rear end t1 of the winding 16a can be easily connected to the outer electrode 14a using the electronic component 10. Specifically, if the surface S2a is not substantially L-shaped but substantially rectangular, the winding 16a passes through the long side of the outer electrode 14a at the front and bridges the outer electrode 14a. The rear end t1 of the winding 16a is located near the long side of the outer electrode 14a at the front. If the rear end t1 is pressure-connected, the rear end t1 can slope toward the front of the outer electrode 14a.

[0064] On the other hand, the surface S2a is substantially L-shaped when viewed from the top. More specifically, the surface S2a is substantially L-shaped and includes the main portion 30a and the protrusion portion 32a. The main portion 30a has a rectangular shape with a long side extending in the left-right direction. The protrusion portion 32a protrudes from the right end of the main portion 30a to the front side. The outer electrode 14a straddles the main portion 30a and the protrusion portion 32a. Therefore, when the coil 16a passes through the long side of the main portion 30a at the front side and bridges the outer electrode 14a, the protrusion portion 32a is located at the front side of the rear end t1 of the coil 16a. Accordingly, when the rear end t1 is pressure-connected, the rear end t1 can be prevented from falling toward the front of the outer electrode 14a.The rear end t1 of the winding 16a and the outer electrode 14a can therefore be connected without any problems. For the same reason, the front end t4 of the winding 16b and the outer electrode 14c can be connected without any problems.

[0065] The inventor conducted an experiment, described below, to determine whether the probability of breakage in the winding 16a of the electronic component 10 can be reduced. Specifically, the inventor prepared the first to third test pieces. The first to third test pieces are described below with reference to the attached drawings. Fig. Figure 10 is a diagram illustrating the dimension of each section in the first to third specimens. Fig. 10 is a cross-sectional structure diagram, the same as that shown in Fig. 4. In the drawing, LA and LD represent the width of the flange portion 24a in the left-right direction, LB and LC represent a distance from the upper surface of the winding core portion 22 to the upper end of the flange portion 24a, La represents the width of the winding core portion 22 in the left-right direction, Lb represents the height of the surface S3 in the up-down direction, Lc represents the height of the electrode formation portions 28a and 28b in the up-down direction, and Ld represents the width of the surface S1 in the left-right direction.

[0066] The inventor changed La / LA, Lb / LB, Lc / LC and Ld / LD as shown in Table 1 below. Table 1 Erstes Probestück Zweites Probestück Drittes Probestück La / LA 0,56 0,75 0,75 Lb / LB 0,62 0,25 0 Lc / LC 0,38 0,75 1 Ld / LD 0,08 0,2 0,25

[0067] As shown in Table 1, the values ​​of Lb / LB in the second and third specimens are lower than the value of Lb / LB in the first specimen. This means that the height of the surface S3 in the up-down direction is small in the second specimen, and the surface S3 is absent in the third specimen. Therefore, in the second and third specimens, the segment I1 of the winding 16a includes a portion whose entire line width overlaps the groove space Sp1 when viewed from the front side. That is, the second and third specimens correspond to electronic components that are comparative examples. On the other hand, in the first specimen, the segment I1 does not overlap the groove space Sp1 when viewed from the front side. That is, the first specimen corresponds to an electronic component according to an embodiment of the present disclosure.The inventor found that the segment 11, when viewed from the front side, barely overlapped the groove space Sp1 if the core 12 was designed such that La / LA, Lb / LB, Lc / LC and Ld / LD fell within the following range:. 0.47≤La / LA≤0.57 0.45≤Lb / LB≤0.76 0.23≤Lc / LC≤0.45 0.04≤Ld / LD≤0.12

[0068] Circuit modules were manufactured by placing 30 of each of the first to third specimens on circuit boards and applying coating resins to the circuit boards. A first process in which each circuit module is exposed to a low temperature of -40°C for 60 minutes and a second process in which each circuit module is exposed to a high temperature of 90°C for 40 minutes are repeated alternately. One cycle means that the first process and the second process are each performed once. Regarding the third specimen, cracks occurred in two out of 30 specimens at the end of 150 cycles, and cracks occurred in four of the remaining 28 specimens at the end of 500 cycles. Cracks occurred in the second specimen.

[0069] On the other hand, with respect to the first sample, no breakage occurred in any sample at the end of 2000 cycles. From this experiment, it is concluded that the probability of breakage occurring in the winding 16a can be reduced by preventing segment 11 from overlapping the groove space Sp1 when viewed from the front. (First modification)

[0070] A core 12a which is the first modification will be described with reference to the attached drawings. Fig. 11 is a plan view of the core 12a when viewed from the bottom. Fig. 12 is a plan view of the core 12a when viewed from the top.

[0071] The core 12a differs from the core 12 in the structure of the flange portions 24a and 24b. The core 12a will be described below with a focus on a different point.

[0072] The flange portion 24a protrudes from the winding core portion 22 toward the bottom and has surfaces S6 (an example of a sixth surface), S7, S8, and S9. The surface S6 is located at the bottom of the winding core portion 22 and faces the front side. Both ends of the surface S6 in the left-right direction, when viewed from the top, substantially coincide with both ends of the winding core portion 22 in the left-right direction. When viewed from the bottom, the surface S6 is inclined with respect to a surface perpendicular to the front-back direction to extend toward the back side while extending to the left side.

[0073] Surface S7 is adjacent to surface S6 on the right side and has a normal vector extending toward the front side. Surface S8 is adjacent to surface S6 on the left side and has a normal vector extending toward the front side. That is, surfaces S7 and S8 are parallel to the surface perpendicular to the front-rear direction. Surface S9 is the rear surface of the flange portion 24a and has a normal vector extending toward the rear side.

[0074] In the flange section 24a, which is Fig. 11, the distance between surfaces S7 and S9 is longer than that between surfaces S8 and S9. As shown in Fig. 12, the length of the protrusion portion 32a in the front-rear direction is longer than that of the protrusion portion 32b in the front-rear direction.

[0075] The flange portion 24b protrudes from the winding core portion 22 toward the bottom and has surfaces S16, S17, S18, and S19. The surface S16 is located at the bottom of the winding core portion 22 and faces the rear side. Both ends of the surface S16 in the left-right direction, when viewed from the top, substantially coincide with both ends of the winding core portion 22 in the left-right direction. The surface S16, when viewed from the bottom, is inclined with respect to a surface such that it extends toward the rear side while extending to the left side.

[0076] Surface S17 is adjacent to surface S16 on the right side and has a normal vector extending toward the rear side. Surface S18 is adjacent to surface S16 on the left side and has a normal vector extending toward the rear side. That is, surfaces S17 and S18 are parallel to the surface perpendicular to the front-rear direction. Surface S19 is the front surface of flange portion 24b and has a normal vector extending toward the front side.

[0077] In the flange section 24b, which is Fig. 11, the distance between the surfaces S18 and S19 is longer than that between the surfaces S17 and S19. As shown in Fig. 12, the length of the protrusion portion 32c in the front-rear direction is longer than that of the protrusion portion 32d in the front-rear direction.

[0078] The windings 16a and 16b are wound around the core 12a as around the core 12. That is, the windings 16a and 16b extend when viewed from the front, as in Fig. 1, from the front side to the rear side while being wound clockwise around the winding core portion 22 of the core 12a. In this case, a portion of the winding 16a wound around the winding core portion 22, which is closest to the rear side, extends from the right front side to the left rear side on the lower surface of the winding core portion 22. That is, the winding 16a extends along the surface S6. The length of the winding 16a in contact with the core 12 therefore increases, and the inductance value of a coil formed by the winding 16a increases. For the same reason, the inductance value of a coil formed by the winding 16b increases.

[0079] By using an electronic component including the core 12a, the reliability of a connection between the rear end t1 of the winding 16a and the outer electrode 14a can be improved. Specifically, the surface S2a includes the main portion 30a and the protrusion portion 32a and is substantially L-shaped when viewed from the top. The main portion 30a has a substantially rectangular shape with a long side extending in the left-right direction. The protrusion portion 32a protrudes from the right end of the main portion 30a to the front side. The outer electrode 14a straddles the main portion 30a and the protrusion portion 32a. Therefore, when the winding 16a passes through the long side of the main portion 30a at the front side and bridges the outer electrode 14a, the protrusion portion 32a is located at the front side of the rear end t1 of the winding 16a.Specifically, the length of the protruding portion 32a of the core 12a in the front-to-back direction is longer than that of the protruding portion 32b of the core 12 in the front-to-back direction. Further, when the rear end t1 is pressure-connected, using the core 12a can prevent the rear end t1 from falling toward the front of the outer electrode 14a, compared to a case where the core 12 is used. Consequently, the reliability of a connection between the rear end t1 of the coil 16a and the outer electrode 14a can be improved. For the same reason, the reliability of a connection between the front end t4 of the coil 16b and the outer electrode 14c can be further improved. (Further examples)

[0080] The configurations of the electronic component 10, an electronic component including the core 12a, and the circuit module 100 can be optionally combined.

[0081] The front surfaces of the electrode formation sections 28a and 28b may be directly connected to the surface S3. More specifically, as shown in Fig. 1, the front surfaces of the electrode formation sections 28a and 28b are located at the rear of the surface S3. Therefore, the surface S1 is present at the front of the electrode formation sections 28a and 28b. The front surfaces of the electrode formation sections 28a and 28b may be directly connected to the surface S3. In this case, the surface S1 is not present at the front of the electrode formation sections 28a and 28b. Therefore, the entire surface S1 is located between the electrode formation sections 28a and 28b.

[0082] As described above, the present disclosure is useful for an electronic component and a circuit module, and is particularly advantageous due to its suitability for reducing the likelihood of breakage occurring in a winding.

Claims

[1] Electronic component (10) having the following features: a core (12; 12a) comprising a winding core portion (22) extending in a first direction and a flange portion (24a) provided on one side in the first direction at an end portion of the winding core portion (22) and projecting from the winding core portion (22) to one side in a second direction perpendicular to the first direction; a first winding (16a) and a second winding (16b) wound around the winding core portion (22); and an outer electrode (14a), wherein the flange portion (24a) comprises: a flange portion main body (26a) having a first surface (S1) facing the one side in the second direction and located on the one side in the second direction compared to the winding core portion (22), and a first electrode forming portion (28a) and a second electrode forming portion (28b) projecting from the flange portion main body (26a) to one side in the second direction compared to the first surface (S1), wherein the first electrode forming portion (28a), at least a part of the first surface (S1) and the second electrode forming portion (28b) are arranged in this order from one side to the other side in a third direction perpendicular to the first direction and the second direction, wherein the first electrode forming portion (28a) has a second surface (S2a) facing the one side in the second direction, wherein the outer electrode (14a) is provided on the second surface (S2a) and is connected to the first winding (16a), wherein, when viewed from the first direction, a groove space (Sp1, Sp1a, Sp1b) is formed which is surrounded by the first electrode forming portion (28a), the second electrode forming portion (28b) and at least a part of the first surface (S1), wherein a segment (11) of the first winding (16a) between a point at which the first winding is separated from the winding core portion (22) and a point at which the first winding (16a) is brought into contact with the outer electrode (14a) is defined as a predetermined segment, wherein an end portion of the predetermined segment (11) on the one side in the third direction is located in comparison to the groove space (Sp1, Sp1a, Sp1b) on the one side in the third direction, wherein an end portion of the predetermined segment (11) on the other side in the third direction is located compared to the groove space (Sp1, Sp1a, Sp1b) on the other side in the third direction and wherein the predetermined segment (11) extends, when viewed from the first direction, toward the one side in the second direction and toward the one side in the third direction and does not include a portion overlapping the groove space (Sp1, Sp1a, Sp1b) at an entire line width of the first winding (16a), wherein the flange portion main body (26a) has a third surface (S3) facing the other side in the first direction and located between the first surface (S1) and the winding core portion (22) in the second direction, and wherein the predetermined segment (11) comprises a portion which overlaps the third surface (S3) when viewed from the first direction, wherein the third surface (S3) has a normal vector extending to the other side in the first direction and to the one side in the second direction. [2] Electronic component (10) according to claim 1, wherein the first electrode forming portion (28a) has a fourth surface (S4) facing the other side in the third direction, wherein the second electrode forming portion (28b) has a fifth surface (S5) facing the one side in the third direction, wherein the groove space (Sp1, Sp1a, Sp1b) is surrounded by at least a part of the first surface (S1), the fourth surface (S4) and the fifth surface (S5) when viewed from the first direction and wherein the fourth surface (S4) has a normal vector extending toward the other side in the third direction and toward the one side in the second direction, and / or the fifth surface (S5) has a normal vector extending toward the one side in the third direction and toward the one side in the second direction. [3] Electronic component (10) according to claim 1 or claim 2, wherein the second surface (S2a) comprises a main portion (30a) and a projection portion (32a), wherein the main portion (30a) extends in the third direction when viewed from the second direction, wherein the projection portion (32a) projects toward the other side in the first direction from a position remote from an end portion of the main portion (30a) on the other side in the third direction and is located on the one side in the third direction compared to the end portion, and wherein the outer electrode (14a) spans the main portion (30a) and the projection portion (32a). [4] Electronic component (10) according to one of claims 1 to 3, wherein the flange portion (24a) protrudes from the winding core portion (22) to the other side in the second direction and has a sixth surface (S6), wherein the sixth surface (S6) is located on the other side in the second direction compared to the winding core portion (22) and faces the other side in the first direction, and wherein the sixth surface (S6) is inclined with respect to a surface perpendicular to the first direction to extend toward the one side in the first direction, while extending toward the other side in the third direction when viewed from the second direction. [5] Circuit module (100) having the following features: the electronic component (10) according to one of claims 1 to 4; a circuit board (102) having a board main body (104) with a first main surface and a pad electrode (106a) provided on the first main surface; and a coating resin (108), wherein the outer electrode (14a) is electrically connected to the pad electrode (106a), and wherein the coating resin (108) covers at least a part of a surface of the electronic component (10).

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