Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1999-06-03
2001-11-06
Young, Lee (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S605000, C029S608000, C029S606000, C336S192000, C336S223000, C336S175000
Reexamination Certificate
active
06311387
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing an inductor, and more specifically, to a method of manufacturing a chip type inductor to be used a component for suppressing the noise produced by microprocessor or other element which requires a large current.
2. Description of the Related Art
Japanese Unexamined Patent Publication No. 1-253906 discloses a method of injection molding as an example of a conventional method of manufacturing a chip type inductor. A metal coil
30
having a spiral shape is made of a metal conductor as shown in
FIG. 1
, and the metal coil
30
is set in a cavity
40
of a mold
38
for forming a resin molded product
34
shown in FIG.
2
. At the time, the metla coil
30
is placed inside of the cavity
40
such that both ends of the spirally-wound metal coil
30
which are parallel to the axial direction, are forced inside of the cavity
40
of the mold
38
. Then, a molten resin containing magnetic powders is injected into the cavity
40
for forming the resin molded product
34
. After hardening the injected resin, the resin molded product
34
is removed from the cavity
40
. Metal caps
36
are put onto both ends in the longitudinal direction of the resin molded product
34
. Both metal caps
36
and the corresponding end parts of the metal coil
30
are electrically connected to a conductive material so as to provide an inductor
32
having the metal caps
36
defining electrodes as shown in FIG.
2
. In the above-mentioned method of manufacturing and inductor via injection molding, only both end parts of the metal coil
30
are fixed with the mold
38
until the resin is injected into the cavity
40
, such that the middle part of the metal coil
30
is unsupported in the cavity
40
. Therefore, this method experiences a problem with deformation and dislocation of the metal coil
30
with respect to the center in the cavity
40
due to the injection pressure at the time of injecting the molten resin from the gate.
SUMMARY OF THE INVENTION
In order to overcome the problems described above, preferred embodiments of the present invention provide a method of manufacturing a coil inductor which prevents metal coil deformation and metal coil dislocation relative to an axis, which are caused by injection pressure at the time of injecting molten resin from a gate. Furthermore, preferred embodiments of the present invention provide a method of manufacturing an inductor via injection molding so as to produce a large number of inductors in a single one operation and so as to greatly improve the operation efficiency of post-production processing.
According to a first preferred embodiment, a method of manufacturing an inductor having a conductor coil embedded in a magnetic chip containing a magnetic material, with an external terminal electrode electrically connected to the conductor coil on the outer surface of the magnetic chip, includes the steps of holding the conductor coil in a cavity by fitting the conductor coil with a pole-shaped coil supporting member provided in the cavity of a mold for injection molding, performing a primary injection molding by injecting a molten magnetic chip molding material into the cavity, performing a secondary injection molding by removing the coil supporting member from the cavity and injecting a molten magnetic chip molding material into the space in the cavity which had been occupied by the coil supporting member, removing the molded product with the conductor coil embedded therein from the mold for injection molding, and cutting the molded product so as to expose the end parts of the embedded conductor coil.
According to the first preferred embodiment, since the conductor coil is embedded in the magnetic chip via injection molding, a chip inductor can be produced easily. Besides, since the injection molding can be conducted with the conductor coil positioned and held by the coil supporting member in the cavity of the mold for injection molding, the conductor coil is embedded at a predetermined position in the molded product so as to enable mass production of inductors with a homogeneous characteristic and an extremely small proportion of defective items. Moreover, since both ends of the molded product are cut after embedding the conductor coil in the magnetic chip, the ends of the embedded conductor coil are easily and reliably exposed.
A second preferred embodiment provides a method of manufacturing an inductor having a conductor coil embedded in a magnetic chip containing a magnetic material, with an external terminal electrode electrically connected to the conductor coil on the outer surface of the magnetic chip includes the steps of holding the conductor coil in a cavity of a coil supporting member, performing a primary injection molding by injecting a molten magnetic chip molding material into the cavity of the coil supporting member, performing a secondary injection molding by removing the molded product with the conductor coil embedded therein from the coil supporting member so as to be placed in the cavity of the mold for injection molding and injecting a molten magnetic chip molding material into the cavity of the mold for injection molding, removing the molded product with the conductor embedded therein from the mold for injection molding, and cutting the molded product so as to expose the end parts of the embedded conductor coil.
According to the second preferred embodiment, since the conductor coil is embedded in the magnetic chip via injection molding, a chip inductor can be produced easily. Besides, since the injection molding can be performed while the conductor coil is positioned and held by the coil supporting member in the cavity of the coil supporting member, the conductor coil is embedded in a predetermined position in the molded product so as to enable the mass production of inductors with a homogeneous characteristic and an extremely small proportion of defective items. Moreover, since both ends of the molded product are cut after embedding the conductor coil in the magnetic chip, the ends of the embedded conductor coil are easily and reliably exposed.
A third preferred embodiment of the present invention provides a method of manufacturing an inductor according to the processes of the first or second preferred embodiments described above, wherein the conductor coil is held by the coil supporting member with at least one end part of the conductor coil being temporarily attached to the conductor coil itself at the time of the primary injection molding.
According to the third preferred embodiment, since at least one end part of the conductor coil is temporarily attached to the coil, the shape of the conductor coil itself can be maintained so that problems, such as the inability of the end of the conductor coil to be bent inward and put through by the coil supporting member, irregularity of the winding diameter of the conductor coil caused by the end of the conductor coil being released by the injection pressure of the molten molding material, and deterioration of the characteristics caused by the irregularity of the winding density, can be prevented so that generation of a defective product is reliably prevented.
A fourth preferred embodiment provides method of manufacturing an inductor according to the first, second or third preferred embodiments, wherein the end parts of the embedded conductor coils are exposed by cutting the molded product and the conductor coils are separated individually after obtaining a molded product with a plurality of the conductor coils insert-molded in the magnetic chip molding material by the primary injection molding and the secondary injection molding.
According to the fourth preferred embodiment, since the molded product having a plurality of the conductor coils insert-molded can be obtained, the manufacturing process is very efficient and greatly improves mass productivity.
A fifth preferred embodiment includes a method of manufacturing an inductor according to the first, second, third or fourth pref
Oshima Hisato
Shikama Takashi
Sugitani Masami
Keating & Bennett LLP
Murata Manufacturing Co. Ltd.
Trinh Minh
Young Lee
LandOfFree
Method of manufacturing inductor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of manufacturing inductor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of manufacturing inductor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2603193