Inductor devices – With supporting and/or spacing means between coil and core – Preformed insulation between coil and core
Reexamination Certificate
2002-05-07
2004-08-24
Mai, Anh (Department: 2832)
Inductor devices
With supporting and/or spacing means between coil and core
Preformed insulation between coil and core
C336S208000, C336S090000
Reexamination Certificate
active
06781500
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ignition coil for an internal combustion engine (hereinafter, referred to as an ignition coil for short).
2. Description of the Prior Art
A structure of an ignition coil for a motor vehicle is, for example, as described in Japanese Unexamined Patent Publication No. 11-111545, constituted by a primary coil wound around a primary spool, a secondary coil wound around a secondary spool which are concentrically arranged in an outer peripheral side of a rod-like center core, a resin member (a potting member or a cast resin) charged into a gap between these plurality of parts, and the like.
However, since coefficients of linear expansion of the respective constituting parts are different from each other, a crack or the like may be generated between the constituting parts (particularly, in a root side of a collar portion in a spool around which a coil winding is arranged) due to a thermal stress. Further, each of the spools is frequently integrally formed by a resin, however, a flow of mold resin is deteriorated in some shapes thereof, so that a void or the like may be generated. Then, since the generation of the crack, the void or the like causes a dielectric breakdown by each of the spools, it is necessary to restrict and prevent them.
SUMMARY OF THE INVENTION
The present invention has been achieved by taking the conventional problems mentioned above, and an object of the present invention is to provide an ignition coil for an internal combustion engine which can prevent a crack, a void or the like from being generated, and can secure an insulating property between a primary side and a secondary side.
In order to achieve the object mentioned above, in accordance with the present invention, there is provided an ignition coil for an internal combustion engine comprising:
a resin spool
121
formed in a substantially cylindrical shape;
a coil
120
constituted by a coil winding wound around the spool
121
; and
a high electric voltage being supplied to an ignition apparatus in the internal combustion engine,
wherein a plurality of projection portions
121
b
protruding to an outer side in a diametrical direction from an outer peripheral surface of the spool
121
are integrally formed in an end portion in an axial direction on the outer peripheral surface of the spool
121
so as to line up in a circumferential direction, and a size L of a portion in the projection portion
121
b
which is in parallel to an axial direction of the spool
121
is larger than a size T of a portion in the projection portion
121
b
which is in parallel to a direction orthogonal to the axial direction of the spool
121
.
Accordingly, in comparison with the spool in accordance with a prior art mentioned below, a resin flow is hard to get out of order near a portion corresponding to the projection portion
121
b
at a time of forming, and a convoluted void and weld are hard to be generated.
Therefore, in accordance with the present invention, since it is possible to prevent a mechanical strength in a root portion of the projection portion
121
b
from being reduced, it is possible to previously prevent the crack from being generated in the root side of the projection portion
121
b.
In accordance with the present invention, there is provided an ignition coil for an internal combustion engine comprising:
a resin spool
121
formed in a substantially cylindrical shape;
a coil
120
constituted by a coil winding wound around the spool
121
; and
a high electric voltage being supplied to an ignition apparatus in the internal combustion engine,
wherein a projection portion
121
b
protruding to an outer side in a diametrical direction from an outer peripheral surface of the spool
121
and assembled in the spool
121
after being separately formed from the spool
121
is provided in an end portion in an axial direction on the outer peripheral surface of the spool
121
.
Accordingly, since it is possible to make a shape of the spool
121
simple, a resin flow is hard to get out of order at a time of forming the spool
121
. Therefore, it is possible to prevent the crack from being generated in the spool
121
.
In accordance with the present invention, there is provided an ignition coil for an internal combustion engine comprising:
a resin spool
121
formed in a substantially cylindrical shape;
a coil
120
constituted by a coil winding wound around the spool
121
;
a high electric voltage being supplied to an ignition apparatus in the internal combustion engine; and
a resin material having an electric insulating property being charged into a substantially cylindrical housing
172
receiving the coil
120
and the spool
121
, whereby the coil
120
and the spool
121
are molded and fixed,
wherein at least a portion corresponding to the coil
120
in the spool
121
has an inner tube portion
121
&agr; and an outer tube portion
121
&bgr; so as to form a double cylinder structure, a projection portion
121
b
protruding to an outer side in a diametrical direction is formed in an end portion in an axial direction of the outer tube portion
121
&bgr;, and an adhesive strength between the resin material and the outer tube portion
121
&bgr; is smaller than an adhesive strength between the resin material and the inner tube portion
121
&agr;.
Accordingly, since all of the coil windings in the coil
120
become in a state of being wound on the outer tube portion
121
&bgr;, a starting point of the crack is hard to be generated in the portion in which the coil winding of the coil
120
is wound. Therefore, it is possible to prevent the crack from being generated and made progress in the portion close to the coil
120
.
In accordance with the present invention, there is provided an ignition coil for an internal combustion engine comprising:
a resin spool
121
formed in a substantially cylindrical shape;
a coil
120
constituted by a coil winding wound around the spool
121
;
a high electric voltage being supplied to an ignition apparatus in the internal combustion engine; and
a resin material having an electric insulating property being charged into a substantially cylindrical housing
172
receiving the coil
120
and the spool
121
, whereby the coil
120
and the spool
121
are molded and fixed,
wherein an adhesion restraining film
122
which restrains an adhesion between an outer peripheral surface of the spool
121
and the coil winding by the resin material is provided between the outer peripheral surface of the spool
121
and the coil winding, and a distance r2 from the adhesion restraining film
122
in an end portion side in an axial direction of the spool
121
to a center axis of the spool
121
is larger than a distance r1 from the adhesion restraining film
122
in a substantially center portion in the axial direction of the spool
121
to the center axis of the spool
121
.
Accordingly, since a way (time) until the crack gets to a center portion becomes long, it is possible to prevent the spool
121
from being early broken.
In accordance with the present invention, there is provided an ignition coil for an internal combustion engine comprising:
a primary coil
120
and a secondary coil
120
which are coaxially arranged;
a center core inserted to axial core portions in both of the coils
120
and
130
;
an outer peripheral core
140
arranged in an outer peripheral side of both of the coils
120
and
130
;
a substantially cylindrical housing
172
receiving both of the coils
120
and
130
and both of the cores
110
and
140
; and
a resin material having an electric insulating property being charged into the housing
172
, whereby both of the coils
120
and
130
and both of the cores
110
and
140
are molded and fixed,
wherein a slit
141
dividing a part of the outer peripheral coil
140
and extending in a longitudinal direction is provided in the outer peripheral core
140
.
Accordingly, since a rigidity of the outer peripheral core
140
is reduced and the outer peripheral core
140
is deformed at a
Abe Shigeya
Akimoto Katsunori
Aoyama Masahiko
Buma Kaneo
Inagaki Masahiro
Denso Corporation
Mai Anh
Nixon & Vanderhye P.C.
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