Laminated coil component

Abstract

In the laminated coil component of the present application, a hole portion is provided in the vicinity of the side surface of the base body, in a manner that the distance from the front end position of the external electrode to the hole portion is shorter than the distance from the front end position of the external electrode to the coil. Therefore, in the case where a crack is generated from the front end position of the external electrode on the mounting surface of the base body, the crack advances toward the hole portion which is at a shorter distance than the coil. Therefore, in the laminated coil component, it is possible to suppress the case where the crack splits the coil.

Description

Technical Field

[0001] This disclosure relates to a stacked coil component. Background Technology

[0002] Currently, there are known stacked coil components, in which a coil having a coil axis parallel to the stacking direction is disposed within a body having a stacked structure. Japanese Patent Application Publication No. 2015-173197 (Patent Document 1) discloses a structure in which a stacked coil component is soldered onto a substrate in an orientation in which the coil axis of the coil is parallel to the substrate on which the stacked coil component is mounted. Summary of the Invention

[0003] The problem that the invention aims to solve

[0004] In the aforementioned prior art laminated coil components, when the mounted substrate flexes, flexural stress corresponding to the substrate flexure is generated within the substrate, potentially causing cracks originating from the mounting surface of the substrate opposite the substrate. These cracks tend to travel parallel to the layers of the substrate and may cause the coil to split.

[0005] According to various aspects of this disclosure, a stacked coil component is provided to suppress coil splitting caused by cracks.

[0006] Technical solutions for solving the problem

[0007] A stacked coil component according to one aspect of this disclosure includes: a body comprising a plurality of stacked layers, having: a mounting surface parallel to the stacking direction of the plurality of layers and a pair of end faces facing each other in a first direction parallel to the stacking direction of the plurality of layers; a coil disposed within the body, having a coil axis parallel to the first direction; a pair of external electrodes extending continuously from each of the end faces of the body to the mounting surface; a pair of lead conductors disposed through the layers of the body located between the coil and the end faces, electrically connected to the ends of the coil, and exposed from the end faces of the body and connected to the external electrodes; and a vulnerable portion disposed in the layers through which the lead conductors are disposed, wherein in a cross section orthogonal to the mounting surface and parallel to the coil axis, the distance from the front end position of the external electrode on the mounting surface to the vulnerable portion is shorter than the distance from the front end position of the external electrode on the mounting surface to the coil.

[0008] In the aforementioned stacked coil assembly, if a crack originates at the front end of the external electrode on the mounting surface of the substrate, the crack does not travel towards the coil, but rather towards a vulnerable part located closer to the coil. This effectively suppresses the possibility of the crack splitting the coil.

[0009] In other aspects of the stacked coil components, the vulnerable part has an elongated shape that extends parallel to the first direction.

[0010] In other aspects of stacked coil components, multiple vulnerable parts are provided in the layer of the body located between one of a pair of end faces and the coil.

[0011] In other aspects of the stacked coil components, in a cross section orthogonal to the mounting surface and parallel to the coil axis, a weak part is provided on both the side of the mounting surface about the coil axis and the side opposite to the mounting surface.

[0012] In other aspects of laminated coil components, the weak point is the void in the layer that penetrates the body. Attached Figure Description

[0013] Figure 1 This is a perspective view showing a multilayer inductor according to an embodiment.

[0014] Figure 2 It is shown Figure 1 The cross-sectional view of the stacked coil component is shown.

[0015] Figure 3 It is shown Figure 1 The exploded stereo diagram of the stacked state of the primitives shown.

[0016] Figure 4 It shows that there are settings. Figure 2 , 3 A top view of the hollow magnetic layer shown.

[0017] Figure 5 This shows the installation. Figure 2 A cross-sectional view of the morphology of the stacked coil component shown.

[0018] Figure 6 It is Figure 5 An enlarged view of the main part. Detailed Implementation

[0019] Hereinafter, the mode for carrying out this disclosure will be described with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are referred to by the same symbols, and repeated descriptions are omitted.

[0020] Reference Figures 1-3 The structure of the laminated coil component in the embodiment will be described. For example... Figure 1 As shown, the stacked coil component 10 of the embodiment is configured to include a body 12 and a pair of external electrodes 14A and 14B.

[0021] The body 12 has a generally cuboid shape and a pair of end faces 12a and 12b that face each other in the extending direction of the body 12. The body 12 also has four side faces 12c to 12f that extend in the opposite direction of the end faces 12a and 12b and connect the end faces 12a and 12b to each other. In this embodiment, side face 12d is a mounting surface that faces the mounting base when the laminated coil component 10 is mounted, and side face 12c that faces side face 12d becomes the top surface during mounting. When the dimensions in the opposite direction of the end faces 12a and 12b are defined as length, the dimensions in the opposite direction of the side faces 12e and 12f are defined as width, and the dimensions in the opposite direction of the side faces 12c and 12d are defined as thickness, for example, the dimensions of the body 12 are 0.7 mm in length × 0.3 mm in width × 0.45 mm in thickness.

[0022] The base body 12 has a structure in which an internal conductor 18 is disposed inside the magnetic body 16. The base body 12 has a stacked structure. The magnetic body 16 has a stacked structure in which multiple magnetic body layers 17 are stacked in the opposite direction of the end faces 12a and 12b. In this embodiment, viewed from the stacking direction of the base body 12, the magnetic body 16 has a rectangular shape in which the long side is parallel to the opposite direction of the side faces 12c and 12d. In the following description, the opposite direction of the end faces 12a and 12b will also be referred to as the stacking direction or the first direction of the base body 12.

[0023] The magnetic body 16 is made of magnetic materials such as ferrite. The magnetic body 16 is obtained by stacking multiple magnetic body sheets (ferrite green sheets) or magnetic body pastes (e.g., ferrite pastes) that will become magnetic body layers 17 and then firing them. That is, the base body 12 has a stacked structure with multiple magnetic body layers 17, and is a fired base body with fired magnetic body layers 17 stacked on top of each other. The magnetic body layers 17 constituting the base body 12 are composed of magnetic body layers 17A with coil layers 20b to 20e (described later), magnetic body layers 17B with connecting layers 20a (described later), magnetic body layers 17C with connecting layers 20f (described later), and magnetic body layers 17D with lead-out layers 23 (described later). As an example, the number of magnetic layers 17 constituting the base body 12 is generally 50 to 60 layers, with magnetic layer 17A having 40 to 50 layers, and magnetic layers 17B, 17C, and 17D having a combined total of 10 to 20 layers. The number of magnetic layers 17 constituting the base body 12 can be appropriately increased or decreased. In the actual base body 12, the multiple magnetic layers 17 are integrated to the point that the boundaries between their layers are indistinguishable.

[0024] Regarding the thickness of each magnetic layer 17, for example, the thickness of magnetic layer 17A is 5–10 μm, the thickness of magnetic layer 17B is 5–10 μm, the thickness of magnetic layer 17C is 15–20 μm, and the thickness of magnetic layer 17D is 15–20 μm. All magnetic layers 17 may also have the same thickness (e.g., 20 μm).

[0025] The internal conductor 18 is composed of a coil 20 and a pair of lead conductors 22A and 22B. The coil 20 and the lead conductors 22A and 22B of the internal conductor 18 have a stacked structure in the stacking direction of the body 12.

[0026] like Figure 2 As shown, coil 20 has a coil axis Z parallel to the stacking direction of the substrate 12, and is wound around the coil axis Z. In this embodiment, viewed from the stacking direction of the substrate 12, coil 20 is a rectangular loop with its long side parallel to the opposite direction (second direction) of the sides 12c and 12d. In this embodiment, coil axis Z is designed to pass through the center of substrate 12 when viewed from the stacking direction of substrate 12.

[0027] In this embodiment, such as Figure 3 As shown, the coil 20 includes connecting layers 20a and 20f and four types of coil layers 20b to 20e. The connecting layers 20a and 20f, and the coil layers 20b to 20e, are made of, for example, a conductive material containing a metal such as Ag. The coil 20 is formed by a printing method. Specifically, the coil 20 is obtained by applying a conductive paste (e.g., Ag paste) that will become the connecting layers 20a, 20f, and coil layers 20b to 20e onto a green sheet that becomes the magnetic layers 17A to 17C and then firing it.

[0028] Viewed from the stacking direction of the body 12, coil layers 20b to 20e are all U-shaped, forming approximately 3 / 4 of the turns of coil 20. For example, viewed from the stacking direction of the body 12, coil layer 20b has a shape comprising a pair of short sides and a long side of the rectangular loop coil 20. Viewed from the stacking direction of the body 12, coil layer 20c has a shape comprising a pair of long sides and a short side of the rectangular loop coil 20. Coil layer 20d, like coil layer 20b, also comprises a pair of short sides and a long side of the rectangular loop coil 20 when viewed from the stacking direction of the body 12, and is symmetrical to coil layer 20b about the coil axis Z point. Coil layer 20e, like coil layer 20c, also comprises a pair of long sides and a short side of the rectangular loop coil 20 when viewed from the stacking direction of the body 12, and is symmetrical to coil layer 20c about the coil axis Z point.

[0029] A set of coil layers 20b to 20e arranged sequentially in the stacking direction of the substrate 12 overlaps at their ends in the stacking direction of the substrate 12 and is electrically connected to each other via a through-hole conductor (not shown) provided through the magnetic body layer 17A. Each set of coil layers 20b to 20e constitutes three turns of the coil 20. In this embodiment, the coil 20 includes multiple sets of coil layers 20b to 20e.

[0030] A connecting layer 20a is disposed on the uppermost layer of the coil 20, forming one end of the coil 20. The connecting layer 20a is connected to the lower coil layer via a through-hole conductor, and is also connected to the upper lead layer 23 that forms a lead conductor 22A. A connecting layer 20f is disposed on the lowermost layer of the coil 20, forming the other end of the coil 20. The connecting layer 20f is connected to the upper coil layer via a through-hole conductor, and is also connected to the lower lead layer 23 that forms another lead conductor 22B.

[0031] A pair of lead conductors 22A and 22B lead the connecting layers 20a and 20f constituting the ends of the coil 20 to the end faces 12a and 12b of the body 12. Each of the lead conductors 22A and 22B is electrically connected to the connecting layers 20a and 20f constituting the ends of the coil 20. In addition, a pair of lead conductors 22A and 22B protrude from the end face 12a of the body 12 and are respectively connected to a pair of external electrodes 14A and 14B.

[0032] Each of the pair of lead conductors 22A and 22B is disposed through a magnetic layer 17D located between the end faces 12a and 12b of the coil 20 and the body 12. Each of the pair of lead conductors 22A and 22B has a structure in which multiple lead layers 23 are stacked. Figure 3 The diagram illustrates three stacked lead-out layers 23. Each lead-out layer 23 is disposed at the center of the magnetic body layer 17D through which the coil axis Z passes. Each lead-out layer 23 is made of a conductive material containing a metal such as Ag. Each lead-out layer 23 is obtained by filling the through-holes of the green sheet that forms the magnetic body layer 17D with a conductive paste (e.g., Ag paste) and then firing it.

[0033] like Figure 4As shown in (a), in the magnetic body layer 17D where the lead-out layer 23 is provided, two sets of holes 31 are provided at positions separated by the lead-out layer 23 along the long side direction of the magnetic body layer 17D. Each set of holes 31 consists of six circular holes 31, which are arranged neatly in two rows along the short side direction of the magnetic body layer 17D. The positions of the holes 31 are consistent in the magnetic body layers 17D that are stacked vertically in the stacking direction of the base body 12. Therefore, when the magnetic body layers 17D with the lead-out layer 23 overlap each other, the holes 31 provided in each magnetic body layer 17D are interconnected, forming an elongated hole portion 30 that spans multiple magnetic body layers 17D and extends parallel to the stacking direction of the base body 12.

[0034] A pair of external electrodes 14A and 14B are respectively disposed on the end faces 12a and 12b of the substrate 12. In this embodiment, the external electrode 14A integrally covers the entire area of ​​the end face 12a and the side faces 12c to 12f of the area adjacent to the end face 12a. Similarly, the external electrode 14B integrally covers the entire area of ​​the end face 12b and the side faces 12c to 12f of the area adjacent to the end face 12b. Figure 2 The diagram shows the external electrodes 14A and 14B extending continuously from the end faces 12a and 12b of the body 12 to the side faces 12c and 12d. In this embodiment, the external electrodes 14A and 14B on the side faces 12c and 12d extend beyond the lead conductors 22A and 22B to overlap with the coil 20. Each external electrode 14A and 14B is composed of one or more electrode layers. The electrode material constituting each external electrode 14A and 14B can be a metallic material such as Ag.

[0035] like Figure 5 As shown, the aforementioned stacked coil component 10 can be soldered onto the substrate 50. More specifically, the stacked coil component 10 is mounted on the electrodes 52A and 52B of the substrate 50 with the coil axis Z of the coil 20 parallel to the main surface 50a of the substrate 50, and is mounted by solder 54.

[0036] Here, when the substrate 50 flexes, flexural stress corresponding to the flexure of the substrate 50 is generated within the body 12 of the laminated coil component 10, sometimes causing cracks in the body 12. The origin of the crack may become a location where stress easily concentrates, i.e., the front end position P of the external electrodes 14A, 14B on the mounting surface 12d of the body 12 opposite to the substrate 50. If the crack travels parallel to the magnetic layer 17 of the body 12 (i.e., along the thickness direction of the body 12), the crack may cause the coil 20 to split.

[0037] In the aforementioned stacked coil component 10, a void portion 30 (a weak point) is provided in the magnetic body layer 17D where lead conductors 22A and 22B are provided. Since the void portion 30 is a depleted portion, the mechanical strength of its interior and surrounding areas is lower than the mechanical strength of the portion where the magnetic material constituting the magnetic body 16 is present. The void portion 30 is located near the side surface 12d of the base body 12, such as... Figure 6 As shown, the distance D1 from the front end position P of the external electrodes 14A and 14B to the hole portion 30 is set to be shorter than the distance D2 from the front end position P of the external electrodes 14A and 14B to the coil 20.

[0038] Therefore, when a crack originates at the front end position P of the external electrodes 14A and 14B on the mounting surface 12d of the substrate 12, the crack does not travel towards the coil 20 in the thickness direction of the substrate 12, but instead travels towards the hollow portion 30, which is closer to the coil 20, in a direction intersecting with the thickness direction of the substrate 12. Thus, in the laminated coil component 10, the cracking of the coil 20 is effectively suppressed.

[0039] Furthermore, the cross-sectional shape of the hole 31 constituting the hollow portion 30 is not limited to a circular shape; it can also be polygonal or elliptical. The position of the hole 31 in the magnetic layer 17D and the position of the hole 31 can be appropriately changed. For example, as... Figure 4 As shown in (b), the four holes 31 can also be arranged at the four corners of the magnetic layer 17D. Alternatively, two sets of holes 31 can be provided at positions separated by the lead-out layer 23 in the thickness direction of the body 12. In this case, in a cross-section orthogonal to the mounting surface 12d and parallel to the coil axis Z, sets of holes 31 are arranged on one side of the mounting surface 12d about the coil axis Z and on the opposite side to the mounting surface 12d. Thus, the holes 30 can be arranged near both the side surface 12d and the side surface 12c of the body 12. The holes 30 can also be arranged only near the side surface 12d of the body 12.

[0040] Adjacent holes 31 in the stacking direction of the base body 12 may or may not be connected to each other.

[0041] The embodiments of this disclosure have been described above, but this disclosure is not necessarily limited to the above embodiments and various changes can be made without departing from its spirit.

[0042] For example, the weak part can be hollow or solid. For example, the weak part can also be a structure in which a through-hole is formed in the layer constituting the substrate by filling material. For the filling material, a material that is less prone to brittle fracture than the material of the layer constituting the substrate (e.g., a metallic material such as Ag) can be used.

[0043] The shape of the coil is not limited to a rectangular loop; it can also be a square loop, a polygonal loop, a circular loop, or an elliptical loop. When the coil is a square loop, the end face / cross-sectional shape of the element can also be square.

[0044] The height position of the coil (coil shaft) relative to the mounting surface of the substrate is not limited to the middle position of the substrate (the position that divides the substrate into two equal parts), but can also be a position biased towards the top side opposite to the mounting surface.

Claims

1. A laminated coil component, wherein, have: The body comprises multiple stacked layers and has: a mounting surface parallel to the stacking direction of the multiple layers, and a pair of end faces facing each other in a first direction parallel to the stacking direction of the multiple layers; A coil is disposed within the body and has a coil axis parallel to the first direction; A pair of external electrodes extend continuously from each of the end faces of the substrate to the mounting surface; A pair of lead conductors, extending through multiple layers of the body located between the coil and the end face, are electrically connected to the end of the coil and protrude from the end face of the body, connecting to the external electrode; and The vulnerable portion is disposed across the plurality of layers in which the lead conductor is disposed and is connected in a manner that extends parallel to the first direction. In a cross section orthogonal to the mounting surface and parallel to the coil axis, the distance from the front end of the external electrode on the mounting surface to the vulnerable portion is shorter than the distance from the front end of the external electrode on the mounting surface to the coil.

2. The laminated coil component according to claim 1, wherein, The vulnerable part has an elongated shape that extends parallel to the first direction.

3. The laminated coil component according to claim 2, wherein, The vulnerable part reaches the coil and connects to the coil.

4. The laminated coil component according to any one of claims 1 to 3, wherein, Multiple of the aforementioned vulnerable portions are disposed in the layer of the body located between one of the pair of end faces and the coil.

5. The laminated coil component according to claim 4, wherein, In a cross section orthogonal to the mounting surface and parallel to the coil axis, the vulnerable portion is provided on one side of the mounting surface about the coil axis and on the opposite side of the mounting surface.

6. The laminated coil component according to claim 4, wherein, In a cross-section orthogonal to the mounting surface and parallel to the coil axis, two of the weak points are provided on the mounting surface side with respect to the coil axis.

7. The laminated coil component according to claim 5, wherein, In a cross-section orthogonal to the mounting surface and parallel to the coil axis, two of the weak points are provided on the mounting surface side with respect to the coil axis.

8. The laminated coil component according to any one of claims 1 to 3, wherein, The weak part is a pore that penetrates the layer of the substrate.

9. The laminated coil component according to claim 4, wherein, The weak part is a pore that penetrates the layer of the substrate.

10. The laminated coil component according to claim 5, wherein, The weak part is a pore that penetrates the layer of the substrate.

11. The laminated coil component according to claim 6, wherein, The weak part is a pore that penetrates the layer of the substrate.

12. The laminated coil component according to claim 7, wherein, The weak part is a pore that penetrates the layer of the substrate.

13. The laminated coil component according to any one of claims 1 to 3, wherein, The cross-sectional shape of the vulnerable part is circular.

14. The laminated coil component according to claim 4, wherein, The cross-sectional shape of the vulnerable part is circular.

15. The laminated coil component according to claim 5, wherein, The cross-sectional shape of the vulnerable part is circular.

16. The laminated coil component according to claim 6, wherein, The cross-sectional shape of the vulnerable part is circular.

17. The laminated coil component according to claim 7, wherein, The cross-sectional shape of the vulnerable part is circular.

18. The laminated coil component according to claim 8, wherein, The cross-sectional shape of the vulnerable part is circular.

19. The laminated coil component according to claim 9, wherein, The cross-sectional shape of the vulnerable part is circular.

20. The laminated coil component according to claim 10, wherein, The cross-sectional shape of the vulnerable part is circular.

21. The laminated coil component according to claim 11, wherein, The cross-sectional shape of the vulnerable part is circular.

22. The laminated coil component according to claim 12, wherein, The cross-sectional shape of the vulnerable part is circular.

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