Plastic article or earthenware shaping or treating: apparatus – Distinct means to feed – support or manipulate preform stock... – Female mold type means
Reexamination Certificate
2002-02-06
2004-03-09
Davis, Robert B. (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Distinct means to feed, support or manipulate preform stock...
Female mold type means
C425S125000, C425S129100, C425S573000, C425S577000
Reexamination Certificate
active
06702562
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of producing a bead inductor and an apparatus for producing a molded body to be included in a bead inductor.
2. Description of the Related Art
Bead inductors are used as anti-noise or noise elimination components, particularly in microprocessors or other similar devices, in which a large amount of current needs is supplied and transmitted. A bead inductor consisting of a conductor coil embedded in rubber or resin material containing magnetic powder (such as ferrite powder) is known. In general, in forming this type of bead inductor, a conductor coil is embedded in resin or rubber material via injection molding or the like, whereby a molded body is formed. Then, both ends of the molded body are cut to expose both ends of the coil embedded in the resin or the rubber material. Thereafter, metallic caps which define external terminal electrodes, are mounted on the exposed coil ends, for example, by using an electrically conductive, resinous paste or via spot welding.
FIGS. 6 and 7
are sectional views illustrating a method of producing a molded body used to form a bead inductor via injection molding. It is noted that the subject matter shown in
FIGS. 6 and 7
and the description thereof contained herein has not yet been published.
Referring to
FIG. 6
, an injection mold, used to form a molded body to be included in a bead inductor, includes an upper mold portion
1
and a lower mold portion
2
. A cavity
3
in which resin is molded is formed in the upper mold portion
1
. A space
3
a
provided to form a projecting portion on the molded body is formed above the cavity
3
. At the lower mold portion
2
, a spacer pin
4
is arranged to be located within the cavity
3
when the lower mold portion
2
and the upper mold portion
1
are fitted together. A gate
1
a
used to supply molten resin into the cavity
3
is formed in the upper mold portion
1
.
When a molded body used for forming a bead inductor is produced using the mold of
FIG. 6
, a conductor coil, which is formed by winding into a spiral or other shaped configuration, a metallic wire, such as a copper wire, coated with an insulating material, such as polyester resin, is inserted onto the spacer pin
4
. Then, molten resin containing magnetic powder, such as ferrite powder, is injected into the cavity
3
from the gate
1
a
, causing an outer portion to be formed outside of the conductor coil inserted onto the spacer pin
4
.
FIG. 7
is a sectional view showing a state in which the outer portion is formed outside of a conductor coil
5
using the above-described method. As shown in
FIG. 7
, the conductor coil
5
is embedded in the molded body
6
, and the spacer pin
4
is located inside of the conductor coil
5
. This spacer pin
4
is pulled out of the molded body
6
in order to allow formation of an inner portion located inside of the conductor coil
5
.
FIGS. 8A
,
8
B, and
8
C are sectional views illustrating the steps carried out to form an inner portion inside of the conductor coil
5
via molding.
FIG. 8A
illustrates the molded body
6
, with the upper mold portion
1
and the lower mold portion
2
being separated from each other as a result of moving the upper mold portion
1
upward from its position shown in FIG.
7
. The spacer pin
4
is disposed in the molded body
6
, and is mounted on the lower mold portion
2
. The molded body
6
has a protruding portion
6
a
at the top portion thereof. The protruding portion
6
a
is removed by cutting or a similar process, thereby, allowing the spacer pin
4
in the molded body
6
to be pulled upward and removed therefrom.
FIG. 8B
illustrates a state after removal of the spacer pin
4
by the above-described method. A space
6
b
is formed in the molded body
6
as a result of the removal of the spacer pin
4
. With the space
6
b
being formed in the molded body
6
, the upper mold portion
1
is fitted onto the lower mold portion
2
again, as shown in
FIGS. 6 and 7
. From the gate
1
a
, molten resin is supplied into the mold so as to flow into the space
6
b
, causing an inner portion to be formed inside of the conductor coil
5
.
FIG. 8C
is a sectional view illustrating a state after formation of an inner portion inside of the conductor coil
5
via molding. A protruding portion
6
c
corresponding to a configuration of the space
3
a
of
FIG. 6
is formed at the top portion of the molded body
6
, while a protruding portion
6
d
is formed at the bottom portion of the molded body
6
so as to be disposed in the space in the lower mold portion
2
where the spacer pin
4
was inserted.
FIG. 9
is a sectional view of the molded body
6
formed by the above-described molding method. The conductor coil
5
is embedded in the molded body
6
. The protruding portion
6
c
is formed at the top portion of the molded body
6
, while the protruding portion
6
d
is formed at the bottom portion of the molded body
6
. By cutting the molded body
6
, using, for example, a dicing saw, along cutting lines A—A and B—B, the ends of the conductor coil
5
in the molded body
6
are exposed. Metallic caps are electrically connected and mounted to the exposed ends of the conductor coil
5
, for example, by using electrically conductive resinous paste or via spot welding.
FIGS. 10 and 11
are a side view and a plan view illustrating a bead inductor having metallic caps mounted thereon. One end sa of the conductor coil
5
is electrically connected to a metallic cap
7
, while the other end
5
b
of the conductor coil
5
is electrically connected to a metallic cap
8
. The metallic caps
7
and
8
are used as external terminal electrodes.
In the above-described bead inductor and method of forming thereof, the spacer pin is removed after formation of the outer portion located outside of the conductor coil via molding. To remove the spacer pin, it is necessary to open the mold and to cut the protruding portion at the top portion of the molded body. This makes it difficult to automate and simplify the injection molding cycle. Therefore, when the conventional bead inductor production method is used, molded bodies cannot be formed with high productivity.
SUMMARY OF THE INVENTION
To overcome the problems described above, preferred embodiments of the present invention provide a method of manufacturing a bead inductor and a bead inductor molded body producing apparatus, which achieve improved and highly efficient production of bead inductor molded bodies having a conductor coil embedded therein.
According to a first aspect of preferred embodiments of the present invention, there is provided a method of producing a bead inductor, in which a molded body having a hollow core conductor coil embedded in rubber or resin material containing magnetic powder is formed, and in which both ends of the conductor coil in the molded body are exposed to electrically connect external terminal electrodes to both of the exposed ends of the conductor coil, the method including the steps of forming an outer portion outside of the conductor coil via molding, by disposing the conductor coil in a cavity of a mold having a first gate and a second gate formed therein, disposing a spacer pin which passes through the core of the conductor coil and extends up to the second gate to close the second gate, and supplying the rubber or the resin material containing magnetic powder into the mold cavity from the first gate and forming the molded body with the conductor coil embedded therein, by, after the formation of the outer portion outside of the conductor coil, closing the first gate, pulling the spacer pin out of the mold cavity, and supplying from the second gate the rubber or the resin material containing magnetic powder into a space formed as a result of the removal of the spacer pin so as to extend through the core of the conductor coil, in order to form an inner portion inside of the conductor coil.
In such a case, after the formation of the outer portion outside of the conductor coil, the spacer pin is
Inoue Jun-ichi
Oshima Hisato
Shikama Takashi
Sugitani Masami
Davis Robert B.
Keating & Bennett LLP
Murata Manufacturing Co. Ltd.
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