Inductor

Details Inductor Inductor

2001-01-30

2002-07-02

Mai, Anh (Department: 2832)

Inductor devices

Coil or coil turn supports or spacers

Printed circuit-type coil

C336S223000, C336S232000, C336S192000

Reexamination Certificate

active

06414583

ABSTRACT:

FIELD OF THE INVENTION
The present invention is related to an inductor, and especially to an inductor without a gap spacer.
BACKGROUND OF THE INVENTION
As shown in
FIGS. 1
a
and
1
b
, a conventional inductor
10
includes a bobbin
20
, a U-shaped magnetic core member
30
, an I-shaped magnetic core member
50
, and a spacer
60
. Several rounds of wires are wound on the bobbin
20
to be employed as a coil of the inductor
10
. Because the magnetic core of the inductor
10
is constituted by the U-shaped magnetic core member
30
and the I-shaped magnetic core member
50
, this inductor
10
is commonly called a “UI inductor”. The U-shaped magnetic core member
30
has a concavity
35
on a side wall thereof. The U-shaped magnetic core member
30
is engaged with the bobbin
20
but the opening of the central hole of the bobbin
20
is exposed out of the concavity
35
of the U-shaped magnetic core member
30
. The spacer
60
is disposed between the adjacent magnetic core members
30
,
50
to space the core members out of contact with each other, thereby reducing magnetic interference therebetween. The spacer
60
may be made of a non-magnetic material, such as plastic, aluminum or paint, which does not cause any magnetic interference between the two magnetic core members
30
,
50
and the two magnetic core members
30
,
50
may be fixed and held through the spacer
60
with a certain space therebetween. Typically, this spacer
60
is made of an insulating material and adhered to one end of the I-shaped magnetic core member
50
. The end of the I-shaped magnetic core member
50
with the spacer
60
is inserted into the central hole of the bobbin
20
through the concavity
35
for allowing the spacer
60
to be attached to the U-shaped magnetic core member
30
so as to assemble the inductor
10
as shown in
FIG. 1
a
. Briefly, the function of the spacer
60
is to form a gap between the I-shaped magnetic core member
50
and the U-shaped magnetic core member
30
so that the inductance of the inductor
10
can be changed by adjusting the spacer size.
However, when manufacturing such an inductor, there exists some problems as follows.
(1) When the I-shaped magnetic core member
50
is inserted into the hole of the bobbin
20
, the spacer
60
may be adhered to the inner wall of the central hole of the bobbin
20
due to its adhesive property. If the I-shaped magnetic core member
50
is forcedly inserted into the bobbin
20
, the spacer
60
may be deformed, thereby influencing the thickness of the spacer
60
and generating an error of the gap, so that the predetermined inductance can not be obtained.
(2) It is uneasy to precisely control the length of the I-shaped magnetic core member
50
inserted into the bobbin
20
.
(3) One end of the I-shaped magnetic core member
50
is attached to the U-shaped magnetic core member
30
only through the spacer
60
. When manufacturing the inductor, the gap may become larger because of the thermal expansion of the spacer so that the inductance of the inductor may be changed.
(4) If the gap is too large or the spacer
60
is too thick, the other end of the I-shaped magnetic core member
50
will be protruded over the edge of the bobbin
20
, or even over the pin
70
of the bobbin
20
, after inserting the I-shaped magnetic core member
50
into the central hole of the bobbin
20
.
(5) The size of the spacer
60
must be matched with that of the central hole of the bobbin
20
. If the size of the spacer
60
is too big, the I-shaped magnetic core member
50
can not be smoothly inserted into the central hole of the bobbin
20
. If the size of the spacer
60
is too small, the spaced area between the I-shaped magnetic core member
50
and the U-shaped magnetic core member
30
may be insufficient.
Therefore, it is desirable to develop an inductor without any above-described drawbacks and without needing a spacer to form a gap.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an inductor without a gap spacer. According to the present invention, the inductor includes a bobbin having at least one round of wire wound thereon to serve as a coil of the inductor, a first magnetic member coupled with the bobbin, and a second magnetic member having a first end and a second end, wherein the second magnetic member is inserted into the bobbin from its second end and the first end of the second magnetic member has a protrusion for allowing the second magnetic member to be partially inserted into the bobbin.
Preferably, the first magnetic member is a U-shaped type magnetic core member and the second magnetic member is an I-shaped type magnetic core member. The first and second magnetic members are made of one selected from a relatively soft magnetic material, Mn—Zn ferrite, Ni—Zn ferrite and a silicon steel plate, respectively, and employed as a magnetic core of the inductor.
Preferably, the protrusion of the second magnetic member has a recess formed on an upper surface thereof for allowing a tool to be inserted therein so as to grab the second magnetic member. The recess can be a hole.
Preferably, the second magnetic member is shortened in accordance with a thickness of a reference piece so as to form a gap between the second end of the second magnetic member and the first magnetic member. The height of the reference piece is greater than that of the side wall of the first magnetic member with the concavity. Certainly, the reference piece is removed before the inductor is assembled.


REFERENCES:
patent: 4760366 (1988-07-01), Mitsui
patent: 5760670 (1998-06-01), Yeh et al.
patent: 6294975 (2001-09-01), Chen

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