Denso Corporation

Norihiro Adachi

Tetsuya Miwa

Kanechiyo Terada

Kazuhide Kawai

Kazutoyo Osuka

Yoshimi Nakase

Tomonari Chiba

Yoshitaka Sato

Yoshihiro Shimoide

Akimitsu Sugiura

Katsunori Akimoto

Hiroyuki Wakabayashi

Kazutoyo Oosuka

Keisuke Kawano

Junichi Wada

Masahiko Aoyama

Masafuyu Sano

Atsuyuki Konishi

Osamu Sugie

Katsuhisa Kato

Tomonori Ishikawa

Kaneo Buma

Naruhiko Inayosi

Masaharu Shimohata

An ignition coil for an internal combustion engine includes a primary bobbin including a winding cylinder part and a connection part between the winding cylinder part and a connector part, a primary coil including a primary main coil and a primary sub coil, and a secondary coil. When one of the primary main coil and the primary sub coil that includes an innermost coil part around the winding cylinder part is defined as a firstly-wound coil and the other is defined as a secondly-wound coil, firstly-wound ends, which are ends of the firstly-wound coil, and secondly-wound ends, which are ends of the secondly-wound coil, are attached to the connection part, and a shortest distance from a central axis of the winding cylinder part to each of the firstly-wound ends is smaller than a shortest distance from the central axis of the winding cylinder part to each of the secondly-wound ends.

Ignition coil for internal combustion engine

An ignition coil includes a center core, a first core member, and a second core member. The first core member includes a first core-facing portion facing a front core surface of the center core and a first core side portion extending rearward from the first core-facing portion. The second core member includes a second core-facing portion facing a rear core surface of the center core and a second core side portion extending frontward from the second core-facing portion. The first core-facing portion has an end surface contacting a portion of the second core side portion to create a first contact region. Similarly, the second core-facing portion has an end surface contacting a portion of the first core side portion to create a second contact region. The first and second contact regions are shaped to approach frontward close to the first core side portion. This structure enhances productivity of the ignition coil.

Ignition coil

A stick-type ignition coil have a central core, a cylindrical member, primary spool, primary coil, secondary spool, secondary coil, outer core and a resin insulator. The two longitudinal end corners and faces of the core are covered by respective buffer members. The inner circumferential corners of the outer core is supported by ring members. Some of the members disposed radially inside and other members disposed radially outside of the inside members are held slidably to each other in the ignition coil. The spools are made of resin containing a rubber in excess of 5 weight percent and reinforcing materials. The resin insulator contains a flexible material.

Stick-type ignition coil having improved structure against crack or dielectric discharge

An ignition coil includes a housing which contains a central core portion, an inner spool having a first winding, and an outer spool having a second winding. The inner spool extends outward of the central core portion. The outer spool extends outward of the inner spool. A locating member includes a locating rib adjacent to an upper portion of the central core portion. The locating rib is in a gap between the inner spool and the central core portion, and locates the inner spool and the central core portion relative to each other. Insulating resin injected into the housing provides insulation among parts in the housing. At least one of the inner spool and the locating member has a void-escape passage which connects the gap and an outside of the inner spool with each other, and which allows a void to escape from the injected insulating resin in the gap.

A gate to mold a primary spool of an ignition coil device is placed at a part which does not oppose a main part of a secondary coil in the primary spool, that is, at a part other than a coil winding portion. It is preferred to use a resin having a high dielectric withstanding voltage and a high flowability, such as polybutylene terephthalate (PBT) or polyethylene terephthalate (PET), polyphenylene oxide (PPO)/polystyrene (PS), or liquid crystal polymer. By arranging the gate except at the winding portion, resin deterioration or cracks occur only at a part which does not oppose the secondary coil, that is, at a part where a high voltage from the secondary coil is relatively low. An adequate dielectric withstanding voltage is ensured without winding an insulation tape around the winding portion.

Method of injection-molding coil spool of ignition coil device

A stick-type ignition coil to be directly connected to a spark plug via a spring. A high tension case containing a high tension terminal and a spring is integrally connected to the bottom end of a high tension generating portion of the ignition coil. The high tension terminal and the spring are separately supported in the high tension case before the spark plug is connected to the ignition coil. When the spark plug is connected, the spring is compressed and contacts the high tension terminal, thereby making electrical contact between the ignition coil and the spark plug. Since the spring and the high tension terminal are supported on separate positions in the case, the spring can be properly compressed without being distorted or jammed between the high tension terminal and the case.

Ignition coil having spring for connecting the same to spark plug

An ignition coil that can be easily assembled, that assures co-axial alignment of a primary coil, a secondary coil and a center core part, and that generates desired high voltage. A core body is formed to have an outer diameter larger than that of a permanent magnet so that the permanent magnet will not protrude out of the outer peripheral face of the core body. Accordingly, when the center core part is inserted into a secondary spool, the center core part is not caught by the secondary spool and may be readily inserted and assembled therewith. Also, because no bulge is created at the center core part, it is possible to prevent the center core part from tilting within the secondary spool and to readily assure the co-axial alignment of the primary spool, the secondary spool and the center core part. Thus, voltage generated by the secondary coil is prevented from dropping, and high voltage may be applied to the ignition plug.

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Kariya, Japan

Norihiro Adachi