Coil component and manufacturing method therefor

Abstract

A wire wound-type coil component with an integrated structure does not have a bonding portion where there is concern about reliability with respect to a spiral conductive wire, a terminal electrode, and an annular core. A coil component includes a core with an integrated structure, at least part of which is a winding core portion, which has an annular shape having a through-hole, and which is made of a non-conductive material; and a coil conductor with an integrated structure, which has a spiral conductive wire arranged to spirally extend around the winding core portion and first and second terminal electrodes formed at both end portions of the spiral conductive wire, respectively. The coil component is manufactured through three-dimensionally shaping the core, the coil conductor, and a shape holding member for holding a shape of a wall surface of the core defining the through-hole, by using a 3D printer.

Claims

1. A coil component comprising: a core with an integrated structure, at least part of which is a winding core portion, which has an annular shape having a through-hole, and which is made of a non-conductive material; and a coil conductor with an integrated structure, which has a spiral conductive wire arranged so as to spirally extend around the winding core portion and first and second terminal electrodes formed at both end portions of the spiral conductive wire, respectively, wherein the core includes, in addition to the winding core portion, a drum-shaped portion having first and second flange portions respectively provided at a first end and a second end of the winding core portion located on opposite sides to each other, and a plate-shaped portion formed integrally with the drum-shaped portion and spanning between the first and second flange portions in a state of facing the winding core portion while forming the through-hole, and the spiral conductive wire is integrated with the winding core portion, and the first and second terminal electrodes are integrated with the first and second flange portions, respectively.

2. The coil component according to claim 1, wherein the core is made of a magnetic body, and forms a completely closed magnetic path.

3. The coil component according to claim 2, wherein the spiral conductive wire is circular in cross section.

4. The coil component according to claim 2, wherein each of the first and second terminal electrodes has a shape with which the first and second terminal electrodes each cannot pass through the through-hole of the core.

5. The coil component according to claim 1, further comprising: a shape holding member made of an electrically insulating material, with which at least a space between the winding core portion and the plate-shaped portion is filled, wherein a portion of the spiral conductive wire located at least between the winding core portion and the plate-shaped portion is embedded in the shape holding member.

6. The coil component according to claim 5, wherein the shape holding member is made of glass.

7. The coil component according to claim 6, wherein the shape holding member is provided so as to cover the spiral conductive wire and the winding core portion, and part of each of the first and second terminal electrodes.

8. The coil component according to claim 5, wherein the shape holding member is provided so as to cover the spiral conductive wire and the winding core portion, and part of each of the first and second terminal electrodes.

9. The coil component according to claim 5, wherein the spiral conductive wire is circular in cross section.

10. The coil component according to claim 1, wherein the spiral conductive wire is circular in cross section.

11. The coil component according to claim 1, wherein each of the first and second terminal electrodes has a shape with which the first and second terminal electrodes each cannot pass through the through-hole of the core.

12. A manufacturing method for the coil component according to claim 1, the manufacturing method for the coil component comprising: three-dimensionally shaping the core, the coil conductor, and a shape holding member for holding a shape of a wall surface of the core defining the through-hole, by using a 3D printer.

13. The manufacturing method for the coil component according to claim 12, wherein in the three-dimensionally shaping, an ink-jet discharge type 3D printer is used as the 3D printer, and shaping the core with a non-conductive material powder containing solution, shaping the coil conductor with a conductive metal powder containing solution, and shaping the shape holding member with an electrically insulating material powder containing solution, are performed, and the manufacturing method further comprises: firing the core, the coil conductor, and the shape holding member shaped by the 3D printer.

14. The manufacturing method for the coil component according to claim 13, wherein a magnetic powder containing solution is used as the non-conductive material powder containing solution, and a copper powder containing solution or a silver powder containing solution is used as the conductive metal powder containing solution, and a glass powder containing solution, an alumina powder containing solution, or a zirconia powder containing solution is used as the electrically insulating material powder containing solution.

15. The manufacturing method for the coil component according to claim 12, wherein in the three-dimensionally shaping, an ink-jet discharge type 3D printer is used as the 3D printer, and shaping the core with a non-conductive material powder containing solution, shaping the coil conductor with a conductive metal powder containing solution, and shaping the shape holding member with a resin containing solution, are performed, and the manufacturing method further comprises: firing the core, the coil conductor, and the shape holding member shaped by the 3D printer, wherein the firing includes burning off the shape holding member.

16. The manufacturing method for the coil component according to claim 15, wherein a magnetic powder containing solution is used as the non-conductive material powder containing solution, and a copper powder containing solution or a silver powder containing solution is used as the conductive metal powder containing solution, and a glass powder containing solution, an alumina powder containing solution, or a zirconia powder containing solution is used as the electrically insulating material powder containing solution.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view illustrating an outer appearance of a coil component according to an embodiment of the present disclosure;

(2) FIG. 2 is a front view of the coil component illustrated in FIG. 1;

(3) FIG. 3 is a bottom view of the coil component 1 illustrated in FIG. 1;

(4) FIG. 4 is a right side view of the coil component 1 illustrated in FIG. 1;

(5) FIG. 5 is a view for illustrating a manufacturing method for the coil component 1 illustrated in FIG. 1, and is a front view illustrating a shaped object 16a immediately after three-dimensional shaping is started by using a 3D printer;

(6) FIG. 6 is a front view illustrating a shaped object 16b obtained by continuing the three-dimensional shaping from the state illustrated in FIG. 5;

(7) FIG. 7 is a front view illustrating a shaped object 16c obtained by further continuing the three-dimensional shaping from the state illustrated in FIG. 6;

(8) FIG. 8 is a cross-sectional view illustrating part of the shaped object 16c illustrated in FIG. 7, in an enlarged manner;

(9) FIG. 9 is a front view illustrating a shaped object 16d obtained by further continuing the three-dimensional shaping from the state illustrated in FIG. 7;

(10) FIG. 10 is a front view illustrating a shaped object 16e obtained by further continuing the three-dimensional shaping from the state illustrated in FIG. 9;

(11) FIG. 11 is a front view illustrating a shaped object 16f obtained by further continuing the three-dimensional shaping from the state illustrated in FIG. 10;

(12) FIG. 12 is a front view illustrating a shaped object 16g obtained by further continuing the three-dimensional shaping from the state illustrated in FIG. 11 and completing the shaping; and

(13) FIG. 13A shows inductance characteristics of a coil component according to a working example of the present disclosure, and FIG. 13B shows inductance characteristics of a coil component according to a comparative example that is out of the scope of the present disclosure.

DETAILED DESCRIPTION

(14) Referring to FIG. 1 to FIG. 4, a structure of a coil component 1 according to an embodiment of the present disclosure will be described. The illustrated coil component 1 constitutes, for example, a single coil.

(15) The coil component 1 includes a core 2, a coil conductor 3, and a shape holding member 4. Note that in FIG. 1 to FIG. 4, the shape holding member 4 is indicated by the dot-dash line as a transparent member.

(16) The core 2 is constituted of a non-conductive material, but is preferably constituted of a magnetic body such as ferrite or a metal magnetic body. However, the core 2 may be constituted of a non-magnetic body such as alumina. The core 2 includes a drum-shaped portion 8 having a winding core portion 5 having a rectangular cross section, and first and second flange portions 6 and 7 respectively provided at a first end and a second end of the winding core portion 5 located on the opposite sides to each other, and includes a plate-shaped portion 9 spanning between the first and second flange portions 6 and 7. The plate-shaped portion 9 faces the winding core portion 5.

(17) The core 2 forms a completely closed magnetic path when being constituted of a magnetic body, and is an integrated structure. That is, the drum-shaped portion 8 and the plate-shaped portion 9 are integrated. The core 2 forms a through-hole 10 between the winding core portion 5 and the plate-shaped portion 9 facing each other, and has an annular shape as a whole.

(18) The coil conductor 3 includes a spiral conductive wire 11 arranged so as to spirally extend around the winding core portion 5, and first and second terminal electrodes 12 and 13 formed, respectively, at both end portions of the spiral conductive wire 11. More specifically, the first and second terminal electrodes 12 and 13 form connection pieces 14 and 15 protruding into the through-hole 10, respectively, and both the end portions of the spiral conductive wire 11 are connected to the connection pieces 14 and 15, respectively. The coil conductor 3 is an integrated structure. Accordingly, the spiral conductive wire 11 and the first and second terminal electrodes 12 and 13 are integrated.

(19) The spiral conductive wire 11 is preferably circular in cross section (see FIG. 8). According to this configuration, stray capacitance generated between adjacent turns of the spiral conductive wire 11 can be reduced. Furthermore, in order to improve reliability of electrical connection and mechanical fixing to a mounting substrate in a mounting state of the coil component 1, the first and second terminal electrodes 12 and 13 are each required to have a predetermined dimension or more. In this embodiment, each of the first and second terminal electrodes 12 and 13 has a shape with which each terminal cannot pass through the through-hole 10 of the core 2, for example, each of the first and second terminal electrodes 12 and 13 has a dimension larger than that of the through-hole 10. This configuration is a characteristic configuration which can be obtained for the first time by employing a manufacturing method which will be described later.

(20) The shape holding member 4 is a member for holding the shape of a wall surface of the core 2 defining the through-hole 10, and at least a space between the winding core portion 5 and the plate-shaped portion 9 is filled therewith. Accordingly, a portion of the spiral conductive wire 11 located at least between the winding core portion 5 and the plate-shaped portion 9 is embedded in the shape holding member 4. As described above, when the space between the winding core portion 5 and the plate-shaped portion 9 is filled with the shape holding member 4, the strength of the coil component 1 can be increased. Note that the shape holding member 4 has an important function of enabling three-dimensional shaping by using a 3D printer, which is performed in a manufacturing method which will be described later.

(21) The shape holding member 4 is made of an electrically insulating material such as glass, alumina, zirconia, or the like. Among these materials, glass is preferably used for forming the shape holding member 4. This is because glass is relatively inexpensive and the shape holding member 4 made of glass does not adversely affect the electrical characteristics of the coil component 1.

(22) In this embodiment, the shape holding member 4 is provided so as to cover the spiral conductive wire 11 and the winding core portion 5, and part of each of the first and second terminal electrodes 12 and 13. According to this configuration, since the shape holding member 4 covers the main portion of the coil component 1 including the spiral conductive wire 11, the environmental resistance of the coil component 1 can be improved.

(23) Next, an advantageous manufacturing method for the coil component 1 will be described with reference to FIG. 5 to FIG. 12.

(24) The manufacturing method described here is characterized in that the core 2, the coil conductor 3, and the shape holding member 4 are three-dimensionally shaped by using a 3D printer. By three-dimensionally shaping using a 3D printer, the core 2 and the coil conductor 3 of the interlinkage structure can be integrally shaped.

(25) FIG. 12 illustrates a shaped object 16g in which the coil component 1 illustrated in FIG. 2 is turned upside down. By sequentially carrying out steps described below, the shaped object 16g illustrated in FIG. 12 is obtained.

(26) First, as illustrated in FIG. 5, a shaping table 17 is prepared, and three-dimensional shaping using a 3D printer is started on the shaping table 17. Shortly after the start of the three-dimensional shaping, a shaped object 16a to be part of the shape holding member 4 is obtained on the shaping table 17.

(27) Thereafter, the three-dimensional shaping is continued. Then, in accordance with the lapse of time in which the three-dimensional shaping continues, shaped objects 16b, 16c, 16d, 16e, 16f, and 16g are sequentially generated illustrated in FIG. 6, FIG. 7, FIG. 9, FIG. 10, FIG. 11, and FIG. 12, respectively.

(28) In FIG. 6, the shaped object 16b in which the height of a portion to be the shape holding member 4 is increased and which has a portion to be part of the spiral conductive wire 11 in the coil conductor 3 is generated.

(29) Next, in FIG. 7, the shaped object 16c in which the height of a portion to be each of the shape holding member 4 and the spiral conductive wire 11 is increased and which has portions to be part of the winding core portion 5 in the core 2 and part of each of the first and second flange portions 6 and 7 is generated.

(30) Here, referring to FIG. 8 which illustrates part of the shaped object 16c by a cross-sectional view in an enlarged manner, it can be seen that the spiral conductive wire 11 is circular in cross section and is in contact with the winding core portion 5 while being embedded in the shape holding member 4. Furthermore, FIG. 8 clearly illustrates that a predetermined interval is provided between adjacent turns of the spiral conductive wire 11 and these interval portions are filled with the shape holding member 4. Note that depending on the resolution of the 3D printer to be used, the cross-sectional shape of the spiral conductive wire 11 may not draw a clean circle outline as illustrated in FIG. 8, and may have a jagged outline.

(31) Next, in FIG. 9, the shaped object 16d in which the height of a portion to be part of each of the shape holding member 4, the spiral conductive wire 11, and the first and second flange portions 6 and 7 is further increased and which has portions to be part of each of the first and second terminal electrodes 12 and 13 in the coil conductor 3 is generated. In the shaped object 16d, shaping of the winding core portion 5 is completed. Furthermore, the first and second terminal electrodes 12 and 13 are shaped together with the first and second flange portions 6 and 7, respectively, and are thus integrated with the first and second flange portions 6 and 7, respectively.

(32) Next, in FIG. 10, the shaped object 16e in which the height of a portion to be part of each of the first and second flange portions 6 and 7 and the first and second terminal electrodes 12 and 13 is further increased is obtained. In the shaped object 16e, shaping of the shape holding member 4 and the spiral conductive wire 11 is completed.

(33) Next, in FIG. 11, the shaped object 16f in which the height of a portion to be part of each of the first and second flange portions 6 and 7 and the first and second terminal electrodes 12 and 13 is further increased and in which shaping of the plate-shaped portion 9 in the core 2 is started is generated. Here, it should be noted that although the through-hole 10 is formed between the winding core portion 5 and the plate-shaped portion 9, filling the through-hole 10 with the shape holding member 4 makes it possible to shape the plate-shaped portion 9 by the 3D printer.

(34) Next, in FIG. 12, the shaping of the first and second flange portions 6 and 7, the first and second terminal electrodes 12 and 13, and the plate-shaped portion 9 is completed, and the shaped object 16g including all of the elements provided in the coil component 1 illustrated in FIG. 2 is generated.

(35) As described above, the three-dimensional shaping by the 3D printer is completed.

(36) In the three-dimensional shaping step described above, it is preferable to use an ink-jet discharge type 3D printer as a 3D printer. In an ink-jet discharge type 3D printer, the core 2 is shaped with a non-conductive material powder containing solution, the coil conductor 3 is shaped with a conductive metal powder containing solution, and the shape holding member 4 is shaped with an electrically insulating material powder containing solution. Then, the core 2, the coil conductor 3, and the shape holding member 4 shaped by the ink-jet discharge type 3D printer are further fired. With this, the coil component 1 is completed.

(37) In the shaping step described above, more specifically, a magnetic powder containing solution, more preferably, a ferrite powder containing solution or metal magnetic powder containing solution is used as the non-conductive material powder containing solution, a copper powder containing solution or a silver powder containing solution is used as the conductive metal powder containing solution, and a glass powder containing solution with a low dielectric constant, an alumina powder containing solution, or a zirconia powder containing solution is used as the electrically insulating material powder containing solution. When the copper powder containing solution is used as the conductive metal powder containing solution, it is preferable that the above-described firing step be performed under a reducing atmosphere.

(38) Note that the step of firing the core 2, the coil conductor 3, and the shape holding member 4 is usually performed after completing the shaping of the core 2, the coil conductor 3, and the shape holding member 4, but by applying firing with a laser beam instead, for example, the firing may be performed simultaneously with the shaping of the core 2, the coil conductor 3, and the shape holding member 4. This latter firing method is particularly suitable when the copper powder containing solution is used as the conductive metal powder containing solution.

(39) In the embodiment described above, the coil component 1 as a product includes the shape holding member 4, but the shape holding member 4 may not be present in the coil component as a product.

(40) In other words, in the step of three-dimensionally shaping, the core 2 is shaped with a non-conductive material powder containing solution, and the coil conductor 3 is shaped with a conductive metal powder containing solution, but the shape holding member 4 is shaped with a resin containing solution. Then, although the core 2, the coil conductor 3, and the shape holding member 4 shaped by the 3D printer are fired, the shape holding member 4 is burned off in this firing step, and can thus be prevented from remaining in the coil component as a product.

(41) According to the three-dimensional shaping using the 3D printer described above, it is possible to perform design change of the coil component as a product with ease, only by changing a program, as described below.

(42) For example, in the illustrated embodiment, the spiral conductive wire 11 is wound in a single layer, but the spiral conductive wire may be subjected to multilayer winding including two or more layers. Additionally, in the multilayer winding, there may be only one or a plurality of spiral conductive wires. Accordingly, the coil component may be a component configuring a common mode choke coil, a transformer, or the like in addition to a component configuring a single coil. Furthermore, the spiral conductive wire 11 may also be wound around the plate-shaped portion 9 side.

(43) Furthermore, in the illustrated embodiment, the coil component 1 includes two terminal electrodes 12 and 13, but may be a component which includes four terminal electrodes, which includes six terminal electrodes, or in which terminal electrodes are asymmetrically arranged. Furthermore, the shape, size, and arrangement of the terminal electrodes can also be freely changed.

(44) Furthermore, the shape of the core can also be freely changed. For example, it is also easy to form the winding core portion in a conical shape.

(45) Furthermore, the dimension of the coil component or the dimension of each element included in the coil component can also be freely changed.

(46) Furthermore, a large number of coil components can be simultaneously shaped. In this case, the coil components which are simultaneously shaped may be of the same type or of different types.

(47) In FIGS. 13A and 13B, inductance characteristics of a coil component according to a working example of the present disclosure and a coil component according to a comparative example that is out of the scope of the present disclosure are compared. That is, FIG. 13A shows inductance characteristics of the coil component according to the working example, and FIG. 13B shows inductance characteristics of the coil component according to the comparative example.

(48) The coil component according to the working example and the coil component according to the comparative example each were shaped so as to have a planar dimension of 0.4 mm×0.2 mm. Furthermore, the coil component according to the working example had the same structure as that of the coil component 1 illustrated in FIG. 1 to FIG. 4, and the coil component according to the comparative example was shaped so as to have an open magnetic path structure without the plate-shaped portion 9, and so as to have the same cross-sectional area of the winding core portion and the same magnetic path length as those of the coil component according to the working example.

(49) In FIGS. 13A and 13B, the horizontal axis represents the number of turns of the spiral conductive wire on the winding core portion, and the vertical axis represents an inductance value. Additionally, the inductance values in two cases where the magnetic permeability of the core is 60 and is 340 are shown.

(50) First, in the comparative example shown in FIG. 13B, the inductance values were approximately the same in both the cases where the magnetic permeability of the core was 60 and was 340, and the inductance value was less than 500 nH even if the number of turns of the conductive wire was increased up to 20.

(51) On the other hand, in the working example shown in FIG. 13A, in the case where the magnetic permeability of the core was 60, when the number of turns of the conductive wire was 20, the inductance value exceeded 500 nH and increased to nearly 1000 nH. Furthermore, when the magnetic permeability of the core was 340, the inductance value reached nearly 1000 nH even when the number of turns of the conductive wire was 10, the inductance value increased as the number of turns increased to 15 and to 20, and when the number of turns was 20, the inductance value exceeding 3500 nH was obtained.

(52) Although several different embodiments have been described above, in practicing the present disclosure, a partial replacement or combination of configurations is also possible among different embodiments.