Inductor devices – Winding formed of plural coils – Two windings
Reexamination Certificate
1999-10-26
2001-04-10
Mai, Anh (Department: 2832)
Inductor devices
Winding formed of plural coils
Two windings
C336S180000, C336S188000
Reexamination Certificate
active
06215386
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a coil device, and more specifically, it relates to a coil device provided with a plurality of coils at a single core.
2. Discussion of Background
A circuit which is achieved by connecting a plurality of coil devices being independent of one another is employed in various types of circuit apparatuses. For instance, a circuit having a common mode choke coil connected to the secondary winding of a transformer is employed in transmission apparatuses such as a LAN apparatus.
In a standard manufacturing process of a prior art circuit, a transformer and a common mode choke coil are manufactured separately and therefore mounted onto a circuit board separately. Not only does this require numerous mounting steps, but also limits the degree to which high density mounting is possible since a large area on the circuit board for mounting these parts is occupied.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a coil device that makes it possible to reduce the number of required parts by half.
It is a further object of the present invention to provide a coil device with which an improvement is achieved in the mounting density on a circuit board or the like.
It is a still further object of the present invention to provide a coil device achieving a high degree of magnetic efficiency.
It is a still further object of the present invention to provide a coil device with which it is possible to minimize the magnetic coupling among a plurality of coils.
In order to achieve the objects described above, the coil device according to the present invention includes a core, a first coil and a second coil.
The core is provided with at least four through holes. The through holes are provided roughly parallel to one another with a combination of two through holes among them constituting a first through hole pair and a combination of the remaining two through holes constituting a second through hole pair. These achieve a relationship whereby the center line passing through the centers of the through holes in the first through hole pair extends almost perpendicular to the center line passing through the centers of the through holes in the second through hole pair. The first coil passes through the first through hole pair whereas the second coil passes through the second through hole pair.
By adopting such a structure, it is possible to share the core between the first coil and the second coil to achieve a reduction in the number of required parts by half and to achieve an improvement in the mounting density on a circuit board or the like. Also, a toroidal—type closed magnetic circuit is formed by the core relative to the first coil and the second coil. As a result, the magnetic flux leaking to the outside is reduced and magnetic efficiency is improved.
With the through holes and the coils as described, it is possible to ensure that the magnetic flux generated by the current flowing to the first coil does not interlink with the second coil and that the magnetic flux generated by the current flowing to the second coil does not interlink with the first coil. Thus, it is possible to minimize the magnetic coupling between the first coil and the second coil.
The quantity of through holes, their positions and the like may be varied in a number of ways while ensuring that the requirements described above are satisfied. In addition, a number of different modes may be adopted in regard to the shape of the core member, its structure and the like. The present invention discloses examples of such variations and modes.
The first coil and the second coil each typically include two windings to constitute a transformer or a common mode choke coil. According to the present invention, the first coil and the second coil may be connected with each other on the core, or they may be connected outside, at a circuit board, a terminal plate or the like.
In another mode, the core may include a first core member and a second core member which are coupled with each other. By adopting this structure, magnetic characteristics that are suited for the individual coils, i.e., the first coil and the second coil, can be achieved.
According to the present invention, a coil refers to a component that is constituted by winding a wire and a winding refers to the wire member constituting the coil.
REFERENCES:
patent: 2883604 (1959-04-01), Mortimer
patent: 3012177 (1961-12-01), Mortimer
patent: 4052785 (1977-10-01), Duncan
patent: 5705961 (1998-01-01), Yee
patent: 52-104837 (1977-09-01), None
patent: 53-32345 (1978-03-01), None
patent: 62-32514 (1987-02-01), None
patent: 2-25213 (1990-07-01), None
Chamura Toshio
Fukuda Tadashi
Gokita Katsuhiro
Kinoshita Mutsumi
Sasai Hiroshi
Mai Anh
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
TDK Corporation
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