# US 11,309,117 B2 · Inductive element and manufacturing method

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- Number: US 11,309,117 B2
- Document ID: US11309117B2
- Status: Granted
- Kind: B2
- Application number: 15/973,516
- Filed: 2018-05-07
- Published: 2019-09-26
- Granted: 2022-04-19
- Earliest claimed: 2018-03-20
- Assignees: Shenzhen Sunlord Electronics Co., Ltd.
- Applicants: Shenzhen Sunlord Electronics Co., Ltd.
- Inventors: Shengcheng Xia; Youyun Li; Xinshu Yu; Gengxin Xiao
- Web page: https://patentgrep.com/patent/US11309117B2

## CPC

- H01F 17/045: {with core of cylindric geometry and coil wound along its longitudinal axis, i.e. rod or drum core}
- H01F 27/02: Casings
- H01F 1/147: Alloys characterised by their composition {(treatment thereof for enhancing their electromagnetic properties C21D8/12)}
- H01F 27/24: Magnetic cores
- H01F 27/28: Coils; Windings; Conductive connections
- H01F 27/29: Terminals; Tapping arrangements {for signal inductances}
- H01F 27/292: {Surface mounted devices}
- H01F 41/0206: {Manufacturing of magnetic cores by mechanical means (magnetic cores per se H01F27/24)}
- H01F 41/061: Winding flat conductive wires or sheets
- H01F 2017/046: {helical coil made of flat wire, e.g. with smaller extension of wire cross section in the direction of the longitudinal axis}
- H01F 2017/048: {with encapsulating core, e.g. made of resin and magnetic powder}
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES

## Abstract

An inductive element includes a magnetic core, a flat coil wound on a middle column of the magnetic core, and a magnetic plastic package layer covering the magnetic core and the flat coil. Two electrodes connected to two pigtails of the flat coil are exposed outside of the magnetic plastic package layer. The flat coil is configured to enable a width direction of a flat wire of the flat coil to be perpendicular to an axial direction of the middle column of the magnetic core, and the flat wire is stacked layer by layer in the axial direction of the middle column. A manufacturing method for the inductive element is also disclosed herein. By using the wounding method of the flat coil of the inductive element, a height of a product may be reduced while obtaining a same DCR, so that the product is thinner.

## Claims

### Claim 1

An inductive element, comprising a magnetic core, a flat coil wound on a middle column of the magnetic core, and a magnetic plastic package layer covering the magnetic core and the flat coil, wherein two electrodes are connected to two pigtails of the flat coil and the electrodes are exposed outside of the magnetic plastic package layer, the flat coil is configured to enable a width direction of a flat wire of the flat coil to be perpendicular to an axial direction of the middle column of the magnetic core, and the flat wire is stacked layer by layer in the axial direction of the middle column; wherein the magnetic plastic package layer comprises magnetic powder, an organic adhesive, a lubricant, and a curing agent, wherein the lubricant comprises any one or more of stearic acid, aluminum stearate, magnesium stearate, calcium stearate, and zinc stearate;
wherein the magnetic powder comprised in the magnetic plastic package layer is carbonyl iron powder on which passivation and insulation processing is performed, and a particle size D50 of the carbonyl iron powder is 4 μm; solids content in the magnetic powder of the magnetic plastic package layer is between 60 wt % and 90 wt %; the organic adhesive comprises silicon resin and epoxy resin, and content is between 10 wt % and 40 wt %; the curing agent is amine resin, and usage of the curing agent is 6 wt % of silicon resin content the lubricant is magnesium stearate accounting for 0.2 wt % of a total weight; or
wherein the magnetic powder comprised in the magnetic plastic package layer is FeSiCr metal soft magnetic powder on which passivation and insulation processing is performed, and a particle size D50 of the FeSiCr metal soft magnetic powder is 30 μm; solids content in the magnetic powder of the magnetic plastic package layer is between 80 wt % and 97 wt %; the organic adhesive comprises silicon resin, and content is between 3 wt % and 20 wt %; the curing agent is amine resin, and usage of the curing agent is 6 wt % of silicon resin content.

### Claim 2 (depends on 1)

The inductive element according to claim 1, wherein the magnetic plastic package layer is molded or is formed by means of rubber coating.

### Claim 3 (depends on 1)

The inductive element according to claim 1, wherein an entire shape of the magnetic core is T-shaped, bar-shaped, or I-shaped.

### Claim 4 (depends on 1)

The inductive element according to claim 1, wherein a cross sectional shape of the middle column of the magnetic core is a square, a rectangle, an ellipse, a circle, or racetrack-shaped.

### Claim 5 (depends on 1)

The inductive element according to claim 1, wherein the magnetic core is a T-shaped magnetic core, the T-shaped magnetic core comprises a lower blade and the middle column of the magnetic core that is connected to the lower blade, the flat coil is wound on the middle column of the magnetic core, the magnetic plastic package layer covers the flat coil and the magnetic core, but an outer side of and at least a part of a bottom of the lower blade of the magnetic core are exposed outside, to facilitating disposing the electrodes.

### Claim 6 (depends on 1)

The inductive element according to claim 1, wherein the magnetic core is an I-shaped the magnetic core, the I-shaped magnetic core comprises an upper blade, a lower blade, and the middle column of the magnetic core that is connected to and between the upper blade and the lower blade, the flat coil is wound on the middle column of the magnetic core, the magnetic plastic package layer covers the flat coil and the magnetic core, and an outer side of and at least a part of a bottom of the lower blade of the magnetic core are exposed outside, to facilitating disposing the electrodes.

### Claim 7 (depends on 1)

The inductive element according to claim 1, wherein a bottom of the magnetic core is provided with two electrode grooves, metalization layers are formed in the electrode grooves, the two pigtails of the flat coil wound on the middle column of the magnetic core are respectively placed inside each of the two electrode grooves, and the pigtails are fixed in the electrode grooves by means of spot welding; or both a side face and a bottom of the magnetic core are each provided with two electrode grooves, metalization layers are formed in the electrode grooves, the two electrode grooves on the side face of the magnetic core are respectively connected to the two electrode grooves at the bottom of the magnetic core by using the metalization layers, the two pigtails of the flat coil wound on the middle column of the magnetic core are respectively placed inside each of the two electrode grooves on the side face of the magnetic core, and the pigtails are fixed in the electrode grooves by means of spot welding.

### Claim 8 (depends on 1)

A manufacturing method for the inductive element according to claim 1, comprising the following steps:
a. prefabricating the magnetic core and winding the flat coil on the middle column of the magnetic core, and respectively connecting the pigtails of the flat coil to the electrodes disposed on the magnetic core; and
b. covering the magnetic core and the flat coil with a magnetic plastic package layer, and making the electrodes connected to the flat coil be exposed outside of the magnetic plastic package layer, wherein
when the flat coil is wound in step a, the width direction of the flat wire is enabled to be perpendicular to the axial direction of the middle column of the magnetic core, and the flat wire is stacked layer by layer in the axial direction of the middle column, to form the flat coil;
wherein step b comprises: preparing a magnetic plastic package material, wherein magnetic powder comprised in the magnetic plastic package layer is carbonyl iron powder on which passivation and insulation processing is performed, and a particle size D50 of the carbonyl iron powder is 4 μm; solids content in the magnetic powder of the magnetic plastic package layer is between 60 wt % and 90 wt %; the organic adhesive comprises silicon resin and epoxy resin, and content is between 10 wt % and 40 wt %; the curing agent is amine resin, and usage of the curing agent is 6 wt % of silicon resin content magnesium stearate accounting for 0.2 wt % of a total weight is also added, to perform homogenization; and forming the magnetic plastic package layer at a periphery of the coil by using the prepared magnetic plastic package material and by means of molding process, a molding pressure being between 0 MPa to 100 MPa, and then performing baking with 150° C./1 H, to cure an organic component in the magnetic plastic package layer; or
step b comprises: preparing a magnetic plastic package material, wherein magnetic powder comprised in the magnetic plastic package layer is FeSiCr metal soft magnetic powder on which passivation and insulation processing is performed, and a particle size D50 of the FeSiCr metal soft magnetic powder is 30 μm; solids content in the magnetic powder of the magnetic plastic package layer is between 80 wt % and 97 wt %; the organic adhesive comprises silicon resin, and content is between 3 wt % and 20 wt %; the curing agent is amine resin, and usage of the curing agent is 6 wt % of silicon resin content and forming the magnetic plastic package layer at a periphery of the coil by using the prepared magnetic plastic package material and by means of molding process, a molding pressure being between 100 MPa to 300 MPa, and then performing baking with 150° C./1 H, to cure an organic component in the magnetic plastic package layer.