# US 12,009,135 B2 · Coil device

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,009,135 B2
- Document ID: US12009135B2
- Status: Granted
- Kind: B2
- Application number: 17/186,425
- Filed: 2021-02-26
- Published: 2021-09-02
- Granted: 2024-06-11
- Earliest claimed: 2020-02-27
- Assignees: TDK Corporation
- Applicants: TDK Corporation
- Inventors: Syun Ashizawa; Takahiro Banzai; Riku Umeki; Satoshi Sugimoto; Hitoshi Sasaki
- Web page: https://patentgrep.com/patent/US12009135B2

## CPC

- H01F 27/24: Magnetic cores
- H01F 3/14: Constrictions; Gaps, e.g. air-gaps (in magnetic shunt paths H01F3/12)
- H01F 17/04: with magnetic core
- H01F 27/263: {Fastening parts of the core together}
- H01F 27/2852: {Construction of conductive connections, of leads}
- H01F 27/29: Terminals; Tapping arrangements {for signal inductances}
- H01F 41/04: for manufacturing coils {(coils for transformer or inductances H01F27/28)}
- H01F 27/292: {Surface mounted devices}
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES

## Abstract

A coil device includes a main core and a sub core. The main core includes a middle leg for winding a coil body and an outer leg connected with the middle leg via a base portion. The sub core is disposed to face the base portion across the middle leg. A gap between the middle leg and the sub core is wider than that between the outer leg and the sub core.

## Claims

### Claim 1

A coil device comprising:
a main core including a middle leg for winding a coil body and an outer leg connected with the middle leg via a base portion; and
a sub core disposed to face the base portion across the middle leg,
wherein the main core has a relative permeability of 15-100,
a gap between the middle leg and the sub core is wider than that between the outer leg and the sub core,
the sub core is fixed to the main core with an adhesive agent disposed on a top surface of the middle leg,
no adhesive agent exists between the outer leg and the sub core,
the gap between the middle leg and the sub core has a width of 15 to 55 μm, wherein the gap between the middle leg and the sub core is located around the adhesive agent,
the coil body is made of a plate conductor and wound around the middle leg by less than one turn, and
a height from a bottom surface of a recess, formed on the main core for accommodating the coil body, to the top surface of the middle leg is smaller than a height from the bottom surface of the recess to a top surface of the outer leg.

### Claim 2 (depends on 1)

The coil device according to claim 1, wherein the main core includes a metal magnetic material.

### Claim 3 (depends on 1)

The coil device according to claim 1, wherein the sub core has a relative permeability of 15-100.

### Claim 4 (depends on 1)

The coil device according to claim 1, wherein the coil body includes:
a first body extending in a first axis on one side of the middle leg;
a second body extending in the first axis on the other side of the middle leg; and
a third body connecting the first body and the second body so as to surround the middle leg.

### Claim 5 (depends on 4)

The coil device according to claim 4, wherein
a first terminal is provided at one end of the first body in the first axis,
a second terminal is provided at one end of the second body in the first axis,
a first dummy terminal is provided at the other end of the first body in the first axis, and
a second dummy terminal is provided at the other end of the second body in the first axis.

### Claim 6 (depends on 1)

The coil device according to claim 1, wherein the coil body is fixed to the main core or the sub core.

### Claim 7 (depends on 1)

The coil device according to claim 1, wherein the middle leg is wider than the outer leg.

### Claim 8 (depends on 7)

The coil device according to claim 7, wherein the middle leg is 1.5-2.5 times as wide as the outer leg.

### Claim 9 (depends on 1)

The coil device according to claim 1, wherein the gap between the middle leg and the sub core is an air gap.