Coil device

Patent metadata

Field	Value
Publication number	US-10163560-B2
Application number	US-201715698163-A
Country	US
Kind code	B2
Filing date	Sep 7, 2017
Priority date	Sep 30, 2016
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

A coil device, in which an air-core coil of a cylindrical shape is buried in a core including a magnetic powder and a resin, showing, CV value of the below described cross sectional areas, SA1 to SA5, 0.55 or less, when an outer diameter of the air-core coil is “a1”, an inner diameter of the same is “a2”, and a distance between a surface of the core perpendicular to a direction of winding axis and an end of the air-core coil in the direction of winding axis is “h”, is provided. The coil device is superior in DC superimposing characteristic while suppressing the magnetic saturation.

First claim

The invention claimed is:

1. A coil device comprising:
a core comprising a magnetic powder and a resin;
an air-core coil of a cylindrical shape; and
a lead, led from the air-core coil, wherein
at least the entire air-core coil is buried inside the core,
a CV value of below described cross sectional areas, SA 1 to SA 5 , is 0.55 or less, when an outer diameter of the air-core coil is “a 1 ”, an inner diameter of the air-core coil is “a 2 ”, and a distance between a surface of the core perpendicular to a direction of winding axis of the air-core coil and an end of the air-core coil in the direction of winding axis of the air-core coil is “h”, in the coil device,
SA 1 is an area, wherein an area formed by an outer periphery of the core is subtracted by an area formed by an outer periphery of the air-core coil, on a cross section perpendicular to the direction of winding axis of the air-core coil, at ½ of a length of the core in the direction of winding axis of the air-core coil,
SA 2 is an area expressed by the following formula,

SA
2

=

π
⁢

⁢

a
1

⁢

a
2

⁢
h

(

a
1

-

a
2

)

⁢
ln
⁢

⁢

a
1

a
2

[

Mathematical
⁢

⁢
1

]

SA 3 is an area formed by an inner periphery of the air-core coil, on the cross section perpendicular to the direction of winding axis of the air-core coil, at ½ of the length of the core in the direction of winding axis of the air-core coil,
SA 4 is a sum of ½ of the area, wherein the area formed by the outer periphery of the core is subtracted by the area formed by the outer periphery of the air-core coil, and an area shown by πa 1 h×½, on the cross section perpendicular to the direction of winding axis of the air-core coil, at the end of the air-core coil in the direction of winding axis of the air-core coil, and
SA 5 is a sum of ½ of the area formed by the inner periphery of the air-core coil, and an area shown by πa 2 h×½, on the cross section perpendicular to the direction of winding axis of the air-core coil, at the end of the air-core coil in the direction of winding axis of the air-core coil.

2. A coil device comprising:
a core comprising a magnetic powder and a resin;
an air-core coil of a square cylindrical shape; and
a lead, led from the air-core coil, wherein
at least the entire air-core coil is buried inside the core,
a CV value of below described cross sectional areas, SA 1 to SA 5 , is 0.55 or less, when a length of one side forming an outer periphery of the air-core coil is “b 1 ”, a length of one side forming an inner periphery of the air-core coil is “b 2 ” and a distance between a surface of the core perpendicular to a direction of winding axis of the air-core coil and an end of the air-core coil in the direction of winding axis of the air-core coil is “h”, in the coil device,
SA 1 is an area, wherein an area formed by an outer periphery of the core is subtracted by an area formed by an outer periphery of the air-core coil, on a cross section perpendicular to the direction of winding axis of the air-core coil at ½ of a length of the core in the direction of winding axis of the air-core coil,
SA 2 is an area expressed by the following formula,

SA
2

=

4
⁢

b
1

⁢

b
2

⁢
h

(

b
1

-

b
2

)

⁢
ln
⁢

⁢

b
1

b
2

[

Mathematical
⁢

⁢
2

]

SA 3 is an area formed by an inner periphery of the air-core coil, on the cross section perpendicular to the direction of winding axis of the air-core coil, at ½ of a length of the core in the direction of winding axis of the air-core coil,
SA 4 is a sum of ½ of the area, wherein the area formed by the outer periphery of the core is subtracted by the area formed by the outer periphery of the air-core coil, and an area shown by 2b 1 h, on the cross section perpendicular to the direct

Assignees

• Tdk Corp

Inventors

• Sezai Yuji
• Yasuhara Katsushi

Classifications

• H01F27/28

  Coils; Windings; Conductive connections · CPC title

• H01F2017/048

  with encapsulating core, e.g. made of resin and magnetic powder · CPC title

• H01F27/306 Primary

  Fastening or mounting coils or windings on core, casing or other support · CPC title

• H01F17/04 Primary

  with magnetic core · CPC title

• H01F27/2823

  Wires (H01F27/2866 takes precedence) · CPC title