# US 2018/0322997 A1 · Inductor element

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- Number: US 2018/0322997 A1
- Document ID: US20180322997A1
- Status: Published application
- Kind: A1
- Application number: 15/967,769
- Filed: 2018-05-01
- Published: 2018-11-08
- Earliest claimed: 2017-05-02
- Assignees: TDK Corporation
- Applicants: TDK Corporation
- Inventors: Yasuhide YAMASHITA; Katsushi YASUHARA; Chiomi SATO
- Web page: https://patentgrep.com/patent/US20180322997A1

## CPC

- H01F 27/255: made from particles (H01F27/26 takes precedence)
- H01F 3/08: made from powder (powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06)
- H01F 3/10: Composite arrangements of magnetic circuits
- H01F 17/043: {with two, usually identical or nearly identical parts enclosing completely the coil (pot cores)}
- H01F 27/2823: {Wires (H01F27/2866 takes precedence)}
- H01F 27/02: Casings
- H01F 2003/106: {Magnetic circuits using combinations of different magnetic materials}
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES

## Abstract

An inductor element includes a wire-winding portion and a core portion. In the wire-winding portion, a conductor is wound in a coil shape. The core portion surrounds the wire-winding portion and contains a magnetic powder and a resin. The wire-winding portion includes an inner circumferential surface. A winding-wire inner circumferential neighboring region is a region of the core portion within a distance from the inner circumferential surface toward a winding axis of the wire-winding portion. An inner-core central region is a region of the core portion within a distance from the winding axis center toward an existing region of the wire-winding portion in an outward direction perpendicular to the winding axis center. Sα−Sβ1≥5.0% is satisfied, where Sα(%) and Sβ1 (%) are respectively an area ratio of a magnetic powder in the inner-core central region and the winding-wire inner circumferential neighboring region.

## Claims

### Claim 1

An inductor element, comprising:
a wire-winding portion where a conductor is wound in a coil shape; and
a core portion surrounding the wire-winding portion and containing a magnetic powder and a resin,
wherein the wire-winding portion comprises an inner circumferential surface, an outer circumferential surface, and a first end surface and a second end surface opposite to each other in a winding axis center of the wire-winding portion,
wherein a winding-wire inner circumferential neighboring region is defined as a region of the core portion within a predetermined distance from the inner circumferential surface toward the winding axis center,
wherein a winding-wire first end-surface neighboring region is defined as a region of the core portion within a predetermined distance from the first end surface toward an outward direction parallel to the winding axis center,
wherein a winding-wire second end-surface neighboring region is defined as a region of the core portion within a predetermined distance from the second end surface toward the outward direction,
wherein an inner-core central region is defined as a region of the core portion within a predetermined distance from the winding axis center toward an existing region of the wire-winding portion in an outward direction perpendicular to the winding axis center, and
wherein Sα−Sβ1≥5.0% is satisfied, where Sα(%) is an area ratio of a magnetic powder in the inner-core central region, and Sβ1(%) is an area ratio of the magnetic powder in the winding-wire inner circumferential neighboring region.

### Claim 2 (depends on 1)

The inductor element according to claim 1, wherein Sα−Sβ4≥−2.0% is satisfied, where Sα(%) is an area ratio of the magnetic powder in the inner-core central region, and Sβ4(%) is an average of Sβ2 and Sβ3, where Sβ2(%) is an area ratio of the magnetic powder in the first end-surface neighboring region, and Sβ3(%) is an area ratio of the magnetic powder in the second end-surface neighboring region, on a cross section of the inductor element passing the winding axis center and parallel thereto.

### Claim 3 (depends on 2)

The inductor element according to claim 2, wherein Sα−Sβ4≥0% is satisfied.

### Claim 4 (depends on 3)

The inductor element according to claim 3, wherein Sα−Sβ4≥5.0% is satisfied.

### Claim 5 (depends on 1)

The inductor element according to claim 1, wherein Sα≥65% is satisfied.

### Claim 6 (depends on 2)

The inductor element according to claim 2, wherein Sα≥65% is satisfied.

### Claim 7 (depends on 3)

The inductor element according to claim 3, wherein Sα≥65% is satisfied.

### Claim 8 (depends on 4)

The inductor element according to claim 4, wherein Sα≥65% is satisfied.

### Claim 9 (depends on 1)

The inductor element according to claim 1, wherein Sβ1≥60% is satisfied.

### Claim 10 (depends on 2)

The inductor element according to claim 2, wherein Sβ1≥60% is satisfied.

### Claim 11 (depends on 3)

The inductor element according to claim 3, wherein Sβ1≥60% is satisfied.

### Claim 12 (depends on 4)

The inductor element according to claim 4, wherein Sβ1≥60% is satisfied.

### Claim 13 (depends on 5)

The inductor element according to claim 5, wherein Sβ1≥60% is satisfied.

### Claim 14 (depends on 1)

The inductor element according to claim 1, wherein Sβ4≥60% is satisfied, where Sβ4(%) is an average of Sβ2 and Sβ3, where Sβ2(%) is an area ratio of the magnetic powder in the first end-surface neighboring region, and Sβ3(%) is an area ratio of the magnetic powder in the second end-surface neighboring region.

### Claim 15 (depends on 2)

The inductor element according to claim 2, wherein Sβ4≥60% is satisfied, where Sβ4(%) is an average of Sβ2 and Sβ3, where Sβ2(%) is an area ratio of the magnetic powder in the first end-surface neighboring region, and Sβ3(%) is an area ratio of the magnetic powder in the second end-surface neighboring region.

### Claim 16 (depends on 3)

The inductor element according to claim 3, wherein Sβ4≥60% is satisfied, where Sβ4(%) is an average of Sβ2 and Sβ3, where Sβ2(%) is an area ratio of the magnetic powder in the first end-surface neighboring region, and Sβ3(%) is an area ratio of the magnetic powder in the second end-surface neighboring region.

### Claim 17 (depends on 4)

The inductor element according to claim 4, wherein Sβ4≥60% is satisfied, where Sβ4(%) is an average of Sβ2 and Sβ3, where Sβ2(%) is an area ratio of the magnetic powder in the first end-surface neighboring region, and Sβ3(%) is an area ratio of the magnetic powder in the second end-surface neighboring region.

### Claim 18 (depends on 5)

The inductor element according to claim 5, wherein Sβ4≥60% is satisfied, where Sβ4(%) is an average of Sβ2 and Sβ3, where Sβ2(%) is an area ratio of the magnetic powder in the first end-surface neighboring region, and Sβ3(%) is an area ratio of the magnetic powder in the second end-surface neighboring region.

### Claim 19 (depends on 9)

The inductor element according to claim 9, wherein Sβ4≥60% is satisfied, where Sβ4(%) is an average of Sβ2 and Sβ3, where Sβ2(%) is an area ratio of the magnetic powder in the first end-surface neighboring region, and Sβ3(%) is an area ratio of the magnetic powder in the second end-surface neighboring region.