Murata Manufacturing Co., Ltd.

Koki Sasaki

Takaomi Toi

Tetsuya Morinaga

Masahiro Bando

Tetsuo Hatakenaka

Takayuki Hirotsuji

Kazuo Kasahara

Shinya Hirai

Yoshio Hanato

A wire-wound coil includes a core, electrodes, and a wire. The core includes a winding core for winding the wire and a pair of flanges. A depression is formed on the inner lower portion of each of the flanges. The depression has a curved surface that curves inward in a direction from the inner wall to the outer wall of the flange and smoothly connects with the peripheral wall of the winding core. The end portions of the wire are extended along the curved surfaces and the tips of the end portions are bonded to the electrodes. The end portions are in an unstressed state and prevent the generation of tension caused by the contraction of a coating agent.

Wire-wound coil and method for manufacturing the same

A coil-winding method for forming a coil unit includes the steps of winding first and second wires substantially parallel to each other simultaneously around a first layer position of a core to form a first turn, winding the first and second wires simultaneously to form a second turn while the second wire is disposed directly around the core, the first wire of the second turn adjacent to the first turn being disposed between the first and second wires of the first turn in the first layer so as to form a second layer, and winding the first and second wires simultaneously to form a third turn while the second wire is disposed directly around the core, the first wire of the third turn being disposed in the second layer and wound between the second wire of the first turn and the second wire of the second turn in the first layer.

Coil-winding method and coil unit formed by the method

A coil device includes terminal electrodes each including a bottom-surface electrode provided on a bottom surface of a flange, side-surface electrodes provided on side surfaces of the flange, and an end-surface electrode provided on an end surface of the flange at the lower part of the end surface. The end-surface electrode is arranged on the end surface of the flange so that the upper edge of the end-surface electrode is disposed at a first level that is substantially the same as that of the upper edges of the side-surface electrodes in the vicinity of boundaries between the end surface and each side surface of the flange and is disposed at a second level lower than the first level at an approximate central portion of the end surface of the flange.

Method for manufacturing a coil device

An electronic device such as a chip coil including an electric wire firmly connected to electrodes in a highly reliable fashion is constructed to be mounted on a printed circuit board or substrate in a stable and reliable manner. At both ends of a core of the chip coil, there are provided electrodes having a multilayer structure including a high-conductivity layer made of Ag, Ag&mdash;Pd, or a similar material; a solder barrier layer made of Ni; and an easy-soldering layer made of Sn or solder. End portions of the electric wire are embedded in the easy-soldering layer so that the resultant electrode structure has a substantially flat surface. A thermo-compression process is performed so that the end portions of the electric wire are connected to the solder barrier layer via solid welding and to the easy-soldering layer via brazing.

Electronic device having electric wires and method of producing same

Coil device and method for manufacturing the same

An electronic device such as a chip coil including an electric wire firmly connected to electrodes in a highly reliable fashion is constructed to be mounted on a printed circuit board or substrate in a stable and reliable manner. At both ends of a core of the chip coil, there are provided electrodes having a multilayer structure including a high-conductivity layer made of Ag, Ag--Pd, or a similar material; a solder barrier layer made of Ni; and an easy-soldering layer made of Sn or solder. End portions of the electric wire are embedded in the easy-soldering layer so that the resultant electrode structure has a substantially flat surface. A thermo-compression process is performed so that the end portions of the electric wire are connected to the solder barrier layer via solid welding and to the easy-soldering layer via brazing.

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Fukui, Japan

Koki Sasaki