Common mode choke coil, method for manufacturing the same, and circuit board

Patent metadata

Field	Value
Publication number	US-2018286554-A1
Application number	US-201815925583-A
Country	US
Kind code	A1
Filing date	Mar 19, 2018
Priority date	Mar 31, 2017
Publication date	Oct 4, 2018
Grant date	—

Abstract

A common mode choke coil includes: a shaft part; a pair of flange parts formed on both ends of the shaft part to constitute a drum core together with the shaft part; a sheet core bonded, in a manner connecting the pair of flange parts across the shaft part, to the top faces of the flange parts facing away from the bottom faces of the flange parts to be mounted on a circuit board; a coil-shaped conductor constituted by sheathed conductive wires wound around the shaft part; and electrode terminals formed on the flange parts and electrically connected to the ends of the sheathed conductive wires; wherein the bonding surfaces of each of the flange parts and the sheet core have multiple contact areas where the flange part makes direct contact with the sheet core, as well as adhesive areas between the contact areas where an adhesive is disposed.

First claim

We/I claim:

1 . A common mode choke coil, comprising:
a shaft part; a pair of flange parts formed on both ends of the shaft part to constitute a drum core together with the shaft part; a sheet core bonded, in a manner connecting the pair of flange parts across the shaft part, to top faces of the flange parts facing away from bottom faces of the flange parts to be mounted on a circuit board; a coil-shaped conductor constituted by sheathed conductive wires wound around the shaft part; and electrode terminals formed on the flange parts and electrically connected to ends of the sheathed conductive wires; wherein bonding surfaces of each of the flange parts and the sheet core have: (i) multiple contact areas where the flange part makes direct contact with the sheet core, and (ii) adhesive areas between the contact areas where an adhesive is disposed.

2 . The common mode choke coil, according to claim 1 , wherein a surface waviness of the bonding surface of the sheet core is smaller than a surface waviness of the bonding surface of the flange part.

3 . The common mode choke coil according to claim 1 , wherein a surface waviness of the bonding surface of the flange part is 25 μm or less.

4 . The common mode choke coil according to claim 1 , wherein:
the multiple contact areas include a first contact area and a second contact area, and the adhesive areas include a first adhesive area positioned between the first contact area and the second contact area; and when a center of a contacting region of the flange part and the sheet core in the first contact area in a circumferential direction of the coil-shaped conductor positioned in parallel with a bottom face of the flange part is defined as a first contact-area center point, a center of a contacting region of the flange part and the sheet core in the second contact area in a circumferential direction of the coil-shaped conductor positioned in parallel with a bottom face of the flange part is defined as a second contact-area center point, and a widthwise center line of a top face of the flange part in a circumferential direction of the coil-shaped conductor positioned in parallel with a bottom face of the flange part is defined as a center line of the flange part, a distance from the first contact-area center point to the center line of flange part, and a distance from the second contact-area center point to the center line of flange part, in the circumferential direction of the coil-shaped conductor positioned in parallel with the bottom face of the flange part, are both at least 0.25 times a width of a side on the top face of the flange part in the circumferential direction of the coil-shaped conductor positioned in parallel with the bottom face of the flange part.

5 . The common mode choke coil according to claim 4 , wherein the first adhesive area is positioned roughly at a center of the top face of the flange part in the circumferential direction of the coil-shaped conductor positioned in parallel with the bottom face of the flange part.

6 . The common mode choke coil according to claim 1 , wherein an external dimension of the sheet core in an axial direction of the coil-shaped conductor is greater than an external dimension of the drum core in a length direction.

7 . The common mode choke coil according to claim 1 , wherein a rounded shape is formed at a corner of the bonding surface of the flange part, and in an axial direction of the coil-shaped conductor, and a difference between an external dimension of the sheet core and that of the drum core is greater than a radius dimension of the rounded shape at the flange part.

8 . The common mode choke coil according to claim 1 , wherein the bonding surface is away from the sheathed conductive wires.

9 . The common mode choke coil according to claim 8 , wherein side faces joined to the bottom faces of the flange parts have side grooves, and the electrode terminals are positioned inside the side grooves of the flange parts.

10 . The common mode choke coil according to claim 1 , wherein a surface roughness of the bonding surface of the sheet core is lower than a surface roughness of the bonding surface of the flange part.

11 . The common mode choke coil according to claim 1 , wherein a groove is formed in either the bonding surface of the flange part or that of the sheet core, and a volume of a cured adhesive on the bonding surface is smaller than a volume of the groove.

12 . The common mode choke coil according to claim 1 , wherein a surface roughness of the shaft part is lower than a surface roughness of the flange part.

13 . The common mode choke coil according to claim 1 , wherein a fill ratio of magnetic material of the sheet core and that of the shaft part is higher than a fill ratio of magnetic material of the flange part.

14 . The common mode choke coil according to claim 1 , wherein an external dimension of the sheet core in an axial direction of the coil-shaped conductor is 3.2 mm or less.

15 . The circuit board on which a common mode choke coil according to claim 1 is mounted.

16 . A method for manufacturing a common mode choke coil, comprising:
a step to form a drum core and a sheet core; a step to form electrode terminals on the drum core; a step to wind sheathed conductive wires around the drum core to form a coil-shaped conductor; a step to connect both ends of the sheathed conductive wires and the electrode terminals; and a step to apply an adhesive to the sheet core on a jig, install the drum core on the sheet core to which the adhesive has been applied, and stack the jig on which the drum core has been installed with other such jigs, and thereby apply pressure while the adhesive is cured.

17 . An onboard device in which the common mode choke coil according to claim 1 is installed.

Assignees

• Taiyo Yuden Kk

Inventors

• Kojima Tsutomu

Classifications

• H01F27/292

  Surface mounted devices · CPC title

• H01F17/045 Primary

  with core of cylindric geometry and coil wound along its longitudinal axis, i.e. rod or drum core · CPC title

• H01F41/0246

  Manufacturing of magnetic circuits by moulding or by pressing powder (magnetic cores made by moulding or by pressing powder H01F27/255; soft magnetic particles H01F1/20, H01F1/36) · CPC title

• H01F27/266

  Fastening or mounting the core on casing or support (on coil H01F27/30) · CPC title

• H01F2017/0093

  Common mode choke coil · CPC title