Inductor

Abstract

To suppress an eddy current generated in the magnetic core of an inductor.SOLUTION: An inductor 1 incudes: a magnetic core 4 with end surfaces 4E1 and 4E2 and side surfaces 4S1 to 4S4 intersecting with the end surfaces 4E1 and 4E2, the magnetic core being formed in a substrate 2; and a coil 6 wound around the side surfaces 4S1 to 4S4. The end surfaces 4E1 and 4E2 have a plurality of protruding parts 4a1 and 4a2. The distance d between the protruding parts 4a1 and 4a2 is smaller than the wavelength of an electromagnetic wave caused by an eddy current generated in the end surfaces 4E1 and 4E2. The depth D of the protruding parts 4a1 and 4a2 is deeper than a predetermined depth at which the current density of an eddy current is attenuated to a predetermined ratio.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a magnetic core for an inductor. [Background technology]

[0002] 2. Description of the Related Art Inductors having a coil wound around a thin magnetic core have been known (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-249516 [Patent Document 2] JP 2020-155733 A [Patent Document 3] JP 2013-258393 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, according to the above-mentioned conventional techniques, eddy currents occur in the magnetic core. If the magnetic core could be powder molded, the eddy currents could be suppressed, but it is difficult to powder mold a thin magnetic core (especially one that can be considered a planar circuit).

[0005] Therefore, an object of the present invention is to suppress the eddy current generated in the magnetic core of an inductor. [Means for solving the problem]

[0006] The inductor of the present invention has an end face and a side face intersecting the end face, and comprises a magnetic core deposited on a substrate and a coil winding around the side face, wherein the end face has a plurality of protrusions, the spacing between the protrusions is smaller than the wavelength of an electromagnetic wave generated by an eddy current generated at the end face, and the depth of the protrusions is greater than a predetermined depth at which the current density of the eddy current decays to a predetermined percentage.

[0007] In the inductor configured as described above, the magnetic core has an end face and a side face intersecting the end face, and is formed on a substrate. A coil winds around the side face. The end face has a plurality of protrusions. The spacing between the protrusions is smaller than the wavelength of an electromagnetic wave generated by an eddy current generated on the end face. The depth of the protrusions is deeper than a predetermined depth at which the current density of the eddy current attenuates to a predetermined rate.

[0008] In the inductor according to the present invention, the predetermined depth may be a depth at which the current density of the eddy current is 1 / e of the current density at the end surface (where e is the base of the natural logarithm).

[0009] In the inductor according to the present invention, the interval may be constant.

[0010] In the inductor according to the present invention, the interval may take different values.

[0011] In the inductor according to the present invention, the width of the protrusion may be narrowed toward the tip of the protrusion.

[0012] In the inductor according to the present invention, the width of the protrusion may be constant.

[0013] In addition, the inductor according to the present invention may include an inductor in which the width of the protrusion narrows as it approaches the tip of the protrusion, and an inductor in which the width of the protrusion is constant.

[0014] In the inductor according to the present invention, the protrusions may be arranged spaced apart in the width direction of the magnetic core.

[0015] In the inductor according to the present invention, the protrusions may be arranged spaced apart in the thickness direction of the magnetic core.

[0016] In the inductor according to the present invention, the magnetic core may be made of any one of permendur, FeNi, silicon steel, Ni, and CoFeSiB nanocrystalline material.

[0017] In the inductor according to the present invention, the magnetic core may be formed by sputtering.

[0018] In the inductor according to the present invention, the magnetic core may be formed by plating. [Brief description of the drawings]

[0019] [Figure 1] 1 is a plan view of an inductor 1 according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Diagram 3] FIG. 1 is a left side view of an inductor 1 according to a first embodiment. [Figure 4] FIG. 2 is a plan view of an inductor 1 according to a second embodiment of the present invention. [Diagram 5] FIG. 4 is a left side view of the inductor 1 according to the second embodiment. [Figure 6] 11 is a partial enlarged plan view of the vicinity of a protruding portion 4a1 of an inductor 1 according to a third embodiment. FIG. [Figure 7] 7A and 7B are a left side view and a front view, respectively, of an inductor 1 according to a modified example of the first embodiment. [Figure 8] 8(a) and 8(b) are a left side view and a front view of an inductor 1 according to a modified example of the second embodiment. [Figure 9] FIG. 9(a) is a partial enlarged view of a protrusion 4a1 when the interval is a constant value d in the first embodiment, and FIG. 9(b) is a partial enlarged view of a protrusion 4a1 when the interval is different values ​​d1 and d2. [Figure 10] FIG. 10(a) is a partial enlarged view of a convex portion 4a1 when the spacing is a constant value d, and FIG. 10(b) is a partial enlarged view of a convex portion 4a1 when the spacing is different values ​​d1 and d2 in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0021] First embodiment Fig. 1 is a plan view of an inductor 1 according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a left side view of the inductor 1 according to the first embodiment. However, in Fig. 3, a coil 6 is omitted.

[0022] The inductor 1 according to the first embodiment includes a magnetic core 4 and a coil 6 .

[0023] The magnetic core 4 is formed on the substrate 2. For example, the magnetic core 4 is formed by sputtering (thickness 1 to 3 μm) or plating (thickness 5 to 10 μm) on the substrate 2. The material of the magnetic core 4 is, for example, any one of permendur, FeNi, silicon steel, Ni, and CoFeSiB nanocrystalline material.

[0024] Magnetic core 4 has end faces 4E1 and 4E2, and side faces 4S1 to 4S4 (see FIG. 2) that intersect with end faces 4E1 and 4E2. Note that in FIG.

[0025] In FIG. 2, side 4S1 is the surface on the top of magnetic core 4, side 4S2 is the surface on the bottom of magnetic core 4, side 4S3 is the surface on the right side of magnetic core 4, and side 4S4 is the surface on the left side of magnetic core 4.

[0026] Coil 6 winds around side surfaces 4S1 to 4S4. When a current flows through coil 6, an eddy current is generated on end surface 4E1 and end surface 4E2.

[0027] The end face 4E1 has a plurality of protrusions 4a1, and the end face 4E2 has a plurality of protrusions 4a2.

[0028] The interval d between the protrusions 4a1 is smaller than the wavelength of the electromagnetic wave generated by the eddy current generated on the end face 4E1. The interval d between the protrusions 4a2 is smaller than the wavelength of the electromagnetic wave generated by the eddy current generated on the end face 4E2. For example, the interval d is 100 to 900 μm. The interval d is constant.

[0029] However, the interval may not be a constant value d but may be different values. Figure 9 shows a partial enlarged view of the convex portion 4a1 in the first embodiment when the interval is a constant value d (Figure 9(a)), and a partial enlarged view of the convex portion 4a1 when the interval is different values ​​d1 and d2 (Figure 9(b)).

[0030] The case where the interval takes a constant value d (Fig. 9(a)) corresponds to Fig. 1, but it is also possible for the interval to take different values ​​d1, d2 (Fig. 9(b)). Of course, it is also possible for the interval to take three or more values.

[0031] The depth D of the protrusion 4a1 is deeper than the predetermined depth at which the current density of the eddy current attenuates to a predetermined rate. The depth D of the protrusion 4a2 is deeper than the predetermined depth at which the current density of the eddy current attenuates to a predetermined rate. The value of the predetermined depth may be set to a value that makes the current density of the eddy current sufficiently small. For example, the predetermined depth is a depth at which the current density of the eddy current is 1 / e of the current density at the end surface 4E1 and the end surface 4E2 (where e is the base of the natural logarithm).

[0032] The width W of the protrusions 4a1 and 4a2 narrows toward the tips of the protrusions 4a1 and 4a2. The protrusions 4a1 and 4a2 are arranged spaced apart from each other in the width direction of the magnetic core 4.

[0033] Next, the operation of the first embodiment will be described.

[0034] If convex portions 4a1 and 4a2 were not provided, when a current is passed through coil 6, electrons would move over end faces 4E1 and 4E2 of magnetic core 4, generating eddy currents. However, in reality, convex portions 4a1 and 4a2 are provided, and so even if electrons attempt to move over end faces 4E1 and 4E2 of magnetic core 4, their movement is hindered by convex portions 4a1 and 4a2, making it difficult for eddy currents to be generated.

[0035] According to the first embodiment, the eddy current generated in the magnetic core 4 of the inductor 1 can be suppressed.

[0036] The first embodiment may be modified as follows.

[0037] <Modification> 7A and 7B are a left side view and a front view, respectively, of an inductor 1 according to a modified example of the first embodiment. However, in FIG. 7A, the coil 6 is omitted. In addition, in FIG. 7B, only the vicinity of the protruding portion 4a1 is shown.

[0038] In the inductor 1 according to the modification of the first embodiment, the protrusions 4a1 are arranged spaced apart in the thickness direction of the magnetic core 4. Even with this modification, the same effects as those of the first embodiment are achieved.

[0039] Second embodiment The inductor 1 according to the second embodiment differs from the inductor 1 according to the first embodiment in that the width of the protrusions 4a1, 4a2 is constant, whereas the width of the protrusions 4a1, 4a2 becomes narrower toward the tips of the protrusions 4a1, 4a2.

[0040] Fig. 4 is a plan view of the inductor 1 according to the second embodiment of the present invention. Fig. 5 is a left side view of the inductor 1 according to the second embodiment. However, in Fig. 5, the coil 6 is omitted.

[0041] The inductor 1 according to the second embodiment includes a magnetic core 4 and a coil 6. The magnetic core 4 has end faces 4E1, 4E2, and side faces 4S1-4S4 (see FIG. 2) that intersect with the end faces 4E1, 4E2. The coil 6 and the side faces 4S1-4S4 are similar to those in the first embodiment, and a description thereof will be omitted.

[0042] End face 4E1 has a plurality of convex portions 4a1. End face 4E2 has a plurality of convex portions 4a2. The width W of convex portions 4a1 and 4a2 is constant. In addition, convex portions 4a1 and 4a2 are arranged spaced apart in the width direction of magnetic core 4. Other than this, the second embodiment is similar to the first embodiment, and description thereof will be omitted.

[0043] However, the interval may not be a constant value d but may be different values. Figure 10 is a partial enlarged view of convex portion 4a1 in the second embodiment when the interval is a constant value d (Figure 10(a)), and a partial enlarged view of convex portion 4a1 when the interval is different values ​​d1 and d2 (Figure 10(b)).

[0044] The case where the interval takes a constant value d (Fig. 10(a)) corresponds to Fig. 4, but it is also possible for the interval to take different values ​​d1 and d2 (Fig. 10(b)). Of course, it is also possible for the interval to take three or more values.

[0045] The operation of the second embodiment is similar to that of the first embodiment, and therefore a description thereof will be omitted.

[0046] According to the second embodiment, the eddy current generated in the magnetic core 4 of the inductor 1 can be suppressed.

[0047] The second embodiment may be modified as follows.

[0048] <Modification> 8A and 8B are a left side view and a front view, respectively, of an inductor 1 according to a modified example of the second embodiment. However, in FIG. 8A, the coil 6 is omitted. In addition, in FIG. 8B, only the vicinity of the protruding portion 4a1 is shown.

[0049] In the inductor 1 according to the modified example of the second embodiment, the protruding portions 4a1 are arranged spaced apart in the thickness direction of the magnetic core 4. Even with this modified example, the same effects as those of the second embodiment are achieved.

[0050] Third embodiment The inductor 1 according to the third embodiment differs from the inductor 1 according to the first and second embodiments in that the inductor 1 has both convex portions 4a1, 4a2 whose width is constant and convex portions whose width becomes narrower as they approach the tips of the convex portions 4a1, 4a2.

[0051] FIG. 6 is a partial enlarged plan view of the vicinity of a protruding portion 4a1 of an inductor 1 according to the third embodiment.

[0052] The inductor 1 according to the third embodiment has both protrusions 4a1 whose width narrows toward the tip (see the first embodiment) (top three protrusions 4a1) and protrusions 4a1 whose width is constant (see the second embodiment) (bottom three protrusions 4a1).Other than this, it is the same as the first embodiment, and the description will be omitted.

[0053] The operation of the third embodiment is similar to that of the first embodiment, and therefore a description thereof will be omitted.

[0054] According to the third embodiment, the eddy current generated in the magnetic core 4 of the inductor 1 can be suppressed. [Explanation of symbols]

[0055] 1 Inductor 2. Board 4 magnetic core 4E1, 4E2 end face 4a1, 4a2 convex part 4S1~4S4 Side 6 Coils W Width of the protrusion d, d1, d2 Spacing between protrusions D Depth of protrusion

Claims

1. a magnetic core having an end surface and a side surface intersecting the end surface, the magnetic core being formed on a substrate; A coil that wraps around the side surface; Equipped with The end surface has a plurality of protrusions, the interval between the protrusions is smaller than the wavelength of an electromagnetic wave generated by an eddy current generated on the end surface, The depth of the protrusion is greater than a predetermined depth at which the current density of the eddy current attenuates to a predetermined rate. Inductor.

2. 2. The inductor of claim 1, The predetermined depth is a depth at which the current density of the eddy current is 1 / e of the current density at the end surface (where e is the base of the natural logarithm). Inductor.

3. 2. The inductor of claim 1, An inductor in which the spacing is constant.

4. 2. The inductor of claim 1, An inductor in which the spacing has different values.

5. 2. The inductor of claim 1, An inductor in which the width of the protrusion becomes narrower as it approaches the tip of the protrusion.

6. 2. The inductor of claim 1, An inductor in which the width of the protrusion is constant.

7. 2. The inductor of claim 1, The convex portion is The width of the protrusion becomes narrower as it approaches the tip of the protrusion, The width of the protrusion is constant; An inductor having

8. 2. The inductor of claim 1, An inductor in which the protrusions are arranged at intervals in the width direction of the magnetic core.

9. 2. The inductor of claim 1, An inductor in which the protrusions are arranged at intervals in the thickness direction of the magnetic core.

10. 2. The inductor of claim 1, An inductor, wherein the magnetic core is any one of permendur, FeNi, silicon steel, Ni, and CoFeSiB nanocrystalline materials.

11. 2. The inductor of claim 1, An inductor, wherein the magnetic core is formed by sputtering.

12. 2. The inductor of claim 1, An inductor, wherein the magnetic core is plated.

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