Inductor devices – With permanent magnet
Reexamination Certificate
1997-06-03
2001-04-03
Gellner, Michael L. (Department: 2832)
Inductor devices
With permanent magnet
C336S178000, C336S096000
Reexamination Certificate
active
06211763
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an ignition coil apparatus for use in a distributor for supplying a high voltage to the plug of an internal combustion engine at the time of igniting the internal combustion engine.
2. Description of the Prior Art
FIG. 12
shows an example of a prior art ignition coil for an internal combustion engine in which a permanent magnet is arranged in the closed magnetic path of a core. In
FIG. 12
, reference numeral
30
represents a case,
31
a container formed inside the case
30
,
32
a primary coil stored in the container
31
,
32
a
a bobbin to which the primary coil
32
is wound,
32
b
a hole formed at the center of the bobbin
32
a
,
33
a secondary coil stored in the container
31
and arranged around and concentrically with the primary coil
32
,
33
a
a bobbin to which the secondary coil
33
is wound, and
34
a core for forming a single magnetic circuit for magnetically coupling the primary coil
32
and the secondary coil
33
. This core
34
has two U-shaped cut cores
34
a
and
34
b
which are arranged in such a manner that their end surfaces face each other to form a ring-shaped core
34
. The inner foot of the cut core
34
a
is inserted into the hole
32
b
of the bobbin
32
a
of the primary coil
32
from one side of the hole
32
b
whereas the inner foot of the cut core
34
b
is inserted into the hole
32
b
of the bobbin
32
a
from the other side. The end surfaces of these two inner feet are placed in contact with the permanent magnet
35
arranged therebetween. The outer foot of the cut core
34
a
and the outer foot of the cut core
34
b
are arranged along the outer wall of the case
30
to enclose outer portions of the primary coil
32
and the secondary coil
33
and the end surfaces of these two outer feet are in contact with each other. The above-mentioned permanent magnet
35
provides the core
34
with a magnetic flux
37
indicated by a dotted line which is opposite in direction to a magnetic flux
36
indicated by a one-dot chained line, generated in the core
34
while electricity is supplied to the primary coil
32
. Numeral
38
denotes an insulating resin which is poured into the container
31
and solidified after the core
34
is attached to the primary coil
32
and the secondary coil
33
stored in the container
31
.
Consequently, in the ignition coil apparatus shown in this
FIG. 12
, since the permanent magnet
35
provides the core
34
with the magnetic flux
37
opposite in direction to the magnetic flux
36
generated in the core
34
while electricity is supplied to the primary coil
32
, the magnetic flux
36
generated in the core
34
by applying electricity to the primary coil
32
cancels the magnetic flux
37
generated by the permanent magnet
35
and is grown into a saturated magnetic flux which is large enough to saturate the core
34
. Therefore, compared with the case where there is no permanent magnet
35
, magnetic force stored in the core
34
increases and electric power output from the secondary coil
33
rises.
FIG. 13
is a side view of a distributor in which an ignition coil apparatus is arranged coaxially with a shaft rotating in synchronization with the rotation of an internal combustion engine and
FIG. 14
is a sectional view of the ignition coil apparatus of the distributor.
In
FIG. 13
, reference numeral
20
represents a base,
21
the shaft which rotates in synchronization with the rotation of the internal combustion engine and is rotatably mounted on the base
20
,
22
an ignition coil apparatus arranged coaxially with the shaft
21
,
23
an electric unit comprising electronic circuits such as a crank angle sensor, power transistor and other electronic parts,
24
a cap,
25
a connector protruding outward from the electric unit
23
, and
26
a screw. The base
20
, ignition coil apparatus
22
, electric unit
23
and cap
24
are assembled into a single unit in such a manner that the ignition coil apparatus
22
is mounted on the base
20
to which the shaft
21
is attached, the electric unit
23
is arranged on the ignition coil apparatus
22
, and the cap
24
is placed over the electric unit
23
.
In
FIG. 14
, numeral
1
represents a cylindrical case made of a synthetic resin having a bottom portion in the ignition coil apparatus
22
of
FIGS. 13
,
2
a hole formed at the center of the bottom portion of the case
1
for passing the shaft therethrough,
3
a container formed in the case
1
with the wall surrounding the hole
2
and the bottom portion and the outer wall of the case
1
,
4
a primary coil arranged in the container
3
around the hole
2
,
5
a secondary coil arranged in the container
3
around and coaxially with the primary coil
4
, and
6
cores for forming four magnetic circuits for magnetically coupling the primary coil
4
and the secondary coil
5
by supplying a primary current to the primary coil
4
. These cores
6
are stored in the container
3
and arranged around the hole
2
at intervals of a right angle so that they cross-chain the primary coil
4
and the secondary coil
5
. Each core
6
is composed of a pair of U-shaped cut cores
6
a
and
6
b
arranged around the hole
2
at intervals of a right angle and astride the primary coil
4
and the secondary coil
5
from above and below in the direction of the center line of the hole
2
, and the end surfaces of the cut cores
6
a
and
6
b
face each other in vertical direction so that the cores
6
are each ring-shaped to cross-chain the primary coil
4
and the secondary coil
5
at intervals of a right angle. The cut core
6
a
is integrated with the case
1
by insertion at the time when the case
1
is molded, whereas the cut core
6
b
is stored in the container
3
after the primary coil
4
and the secondary coil
5
are stored in the container
3
. The inner foot of the cut core
6
a
is interposed between the primary coil
4
and the wall of the hole
2
whereas the inner foot of the cut core
6
b
is inserted between the primary coil
4
and the wall of the hole
2
from above, and the end surfaces of the inner feet of the two cut cores
6
a
and
6
b
are contacted to each other in a vertical direction. The other foot of the cut core
6
a
is interposed between the secondary coil
5
and the outer wall of the case
1
whereas the other foot of the cut core
6
b
is inserted between the secondary coil
5
and the outer wall of the case
1
, and the end surfaces of the other feet of the two cut cores
6
a
and
6
b
are made apart from each other in vertical direction to form a gap
7
having a predetermined distance therebetween. Numeral
8
represents a synthetic resin cover for aligning the cut core
6
b
with the cut core
6
a
in vertical direction. The extending ends of the four arms of the covers
8
extend from the inner surface of the outer wall of the case
1
and fit in position determination portions of the case
1
, and a back portion of the cut core
6
b
astride the opposing feet is arranged over the cover
8
. Numeral
9
denotes an insulating resin which is poured into the container
3
and solidified after the cut core
6
b
is installed over the primary coil
4
and the secondary coil
5
stored in the container through the cover
8
.
Therefore, in the ignition coil apparatus shown in
FIG. 14
, each time a primary current flows through the primary coil
4
upon ignition of the internal combustion engine, the secondary coil
5
which is magnetically coupled to the primary coil
4
by the core
6
generates a high voltage for igniting the internal combustion engine. At this time, since the core
6
is provided with a high magnetic field by the gap
7
while electricity is supplied to the primary coil
4
, efficiency of magnetism stored in the core
6
by supplying electricity to the primary coil
4
is excellent. Moreover, since the ignition coil apparatus is structured such that the base, electric unit and gap are arranged around the shaft in tiers as shown in FIG.
13
and that a plurality of
Gellner Michael L.
Mitsubishi Denki & Kabushiki Kaisha
Nguyen Tuyen T.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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