JP3125564B2 - Ignition coil for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition coil for an internal combustion engine in which a coil assembly is fitted around an outer periphery of an iron core in a case, and the coil assembly is molded with a casting resin filled in the case. It is about.

[0002]

2. Description of the Related Art In a conventional ignition coil for an internal combustion engine of this type, a coil assembly composed of a primary coil wound on a primary coil bobbin and a secondary coil wound on a secondary coil bobbin has an outer periphery of an iron core. The coil terminal wires at the ends of these coils are soldered and connected to terminal fittings, respectively, and these terminal fittings are supported by bobbin flanges and the like, and the coil assembly including the soldered connection portions of the coil terminal wires is provided. The structure is molded with the casting resin filled in the case. In this case, the bobbin is formed of a thermoplastic resin such as a polyphenylene oxide resin (trade name: Noryl resin) due to moldability and the like, and a thermosetting resin such as an epoxy resin is used as a casting resin.

[0003]

However, the thermoplastic resin and the thermosetting resin have different properties, cannot be adhered to each other even if they are in close contact with each other, have different expansion coefficients depending on temperature, and have a different expansion coefficient due to temperature change. A slight displacement occurs at the joining surface between the thermosetting resin and the thermosetting resin, and a stress of attraction and pressing occurs along the terminal fitting protruding into the thermosetting resin, and the diameter at this time is, for example, 0.04 mm to 0.05. There has been a problem that the terminal wire of the secondary coil formed of a thin copper wire of mm is disconnected at a portion connected to the soldering portion of the terminal fitting.

An object of the present invention is to provide an ignition coil for an internal combustion engine which can prevent a terminal wire of a secondary coil from breaking at a portion connected to a soldering portion of a terminal fitting.

[0005]

According to the present invention, there is provided a coil assembly comprising a primary coil wound around a primary coil bobbin and a secondary coil wound around a secondary coil bobbin. Is fitted to the outer periphery of the iron core, the coil terminal wire at the end of the coil is soldered and connected to a terminal fitting, and the coil assembly is filled in the case including the soldered connection part of the coil terminal wire. It is intended to improve an ignition coil for an internal combustion engine having a structure molded with a casting resin.

In the present invention, a coil terminal wire at the end of the secondary coil is wound around the outer periphery of the terminal fitting supported by the secondary coil bobbin with a required number of turns. The terminal metal part of the coil terminal wire is soldered to the terminal metal part by leaving a plurality of turns on the outer periphery of the secondary coil bobbin connected to the secondary coil as a non-soldering turn part. Connection.

In this case, the terminal fitting for soldering and connecting the coil terminal wire at the end of the secondary coil is fixed to, for example, a flange of the secondary coil bobbin. As the casting resin, for example, a thermosetting resin is used. Further, the secondary coil bobbin is formed of, for example, a thermoplastic resin.

[0008]

As described above, the coil terminal wire at the end of the secondary coil is wound around the outer periphery of the terminal supported by the secondary coil bobbin with a required number of turns. When a plurality of turns on the side connected to the secondary coil on the outer periphery of the secondary coil bobbin are left as non-soldering turn portions, and the turn portions on the leading end side are soldered and connected to the terminal fittings, of the terminal fitting winding portion of the coil terminal wire, A plurality of turns of the non-soldering turn function as expansion and contraction portions of the coil end wire. For this reason, even if the stress of drawing and pressing is generated along the terminal fitting due to the difference in the expansion coefficient between the bobbin molding resin and the casting resin, the stress is applied to a plurality of the terminal fitting winding portions of the coil terminal wire. The non-soldered turn portion of the turn absorbs, and it is possible to prevent disconnection from occurring at the coil terminal wire at the end of the thin secondary coil.

Therefore, the secondary coil bobbin is formed of a thermoplastic resin, and a thermosetting resin is used as a casting resin. Even if the two resins have different coefficients of thermal expansion, the terminal wire of the secondary coil is formed of the terminal fitting. Disconnection can be prevented at a portion connected to the soldering portion.

[0010]

1 to 3 show an embodiment of an ignition coil for an internal combustion engine according to the present invention. The ignition coil for an internal combustion engine according to the present embodiment includes a bottomed case 1 made of a resin such as polybutylene terephthalate, polypropylene, or the like. I have. A primary coil bobbin 3 made of a thermoplastic resin such as a polyphenylene oxide resin (trade name: Noryl resin) is fitted around the outer periphery of the iron core 2 in the case 1. A primary coil 4 is wound around the outer periphery of the primary coil bobbin 3. One of the flanges 3a and 3b at both ends of the primary coil bobbin 3 has a larger outer diameter than the other flange 3b, and a low-voltage connector 5 and a high-voltage connector 6 are integrally formed on the flange 3a. It is provided in.
The terminal fitting 7 of the low-voltage connector 5 protrudes from the outer periphery of the flange 3a. The terminal fitting 8 of the high-voltage connector 6 of the present embodiment has a wood screw shape, and its head protrudes from the inner surface of the flange 3a. A low voltage cord 9 is connected to the low voltage connector 5 by a connector 10. The high-voltage cord 11 is screwed and connected to the high-voltage connector 6 such that the core wire 11 a comes into contact with the wood screw portion of the terminal fitting 8.

A secondary coil bobbin 13 is fitted around the primary coil winding portion of the primary coil bobbin 3.
A secondary coil 14 is wound around the outer periphery of the secondary coil bobbin 13. Flanges 1 at both ends of the secondary coil bobbin 13
Pin-shaped terminal fittings 15a and 15b are supported by 3a and 13b by embedding their bases.

The primary coil bobbin 3 is wound around the primary coil bobbin 3.
The secondary coil 4 and the secondary coil 14 wound around the secondary coil bobbin 13 constitute a coil assembly 16.

A coil terminal wire 4a at one end of the primary coil 4 is wound around the terminal fitting 7 by a required number of turns, and solder 17
Connected.

A coil terminal wire 14a at one end of the secondary coil 14 is wound around the terminal fitting 15a with a required number of turns.
The terminal fitting winding portion 14at of the coil end wire 14a is 2
A plurality of turns on the outer periphery of the secondary coil bobbin 13 connected to the secondary coil 14 are left as non-soldering turn portions 14at1, and the turn portion 14at2 on the distal end side is a terminal fitting 15.
a is connected to the solder 18a.

The head of the terminal fitting 8 is pressed into contact with such a terminal fitting 15a to be electrically connected thereto.

A coil terminal wire 14b at the other end of the secondary coil 14 is wound around the terminal fitting 15b with a required number of turns.
The terminal metal-wound portion 14bt of the coil end wire 14b has a plurality of turns connected to the secondary coil 14 on the outer periphery of the secondary coil bobbin 13 as a non-soldering turn portion 14bt1 in the same manner as described above. 14 bt
2 is connected to the terminal fitting 15b by soldering 18b.
A coil terminal wire 4b at the other end of the primary coil 4 is wound with a required number of turns and connected to the terminal fitting 15b by soldering. Such a coil terminal wire 4b is
It can also be wound around the terminal fitting 15b together with the coil end wire 14b, and can be soldered with the non-soldering turn portion left in the same manner as the method of soldering the coil end wire 14b.

The coil assembly 1 in such a connection state
The case 1 in which the coil assembly 16 is housed is filled with a casting resin 19 made of a thermosetting resin such as an epoxy resin so as to be buried in the coil assembly 16 and hardened.

The coil terminal wires 14a, 14b at the ends of the thin secondary coil 14 are wound around the outer circumferences of the terminal fittings 15a, 15b with a required number of turns.
The plurality of turns on the side connected to the secondary coil 14 on the outer periphery of the secondary coil bobbin among the terminal metal-wound portions 14at and 14bt of the terminal fittings 14a and 14b are non-soldered turn portions 14at1,
14 bt1 and the turn part 14at2 on the tip side
, 14 bt2 are soldered to the terminal fittings 15a, 15b.
a, 18b, these coil end wires 14
a, 14b, a plurality of turns of non-soldering turn portions 14at1, 1 of terminal winding portions 14at, 14bt.
4bt1 acts as a telescopic part of the coil end wires 14a, 14b. For this reason, even if a stress of drawing and pressing is generated along the terminal fittings 15a and 15b due to a difference in expansion coefficient, the stress is applied to a plurality of the terminal fitting winding portions 14at and 14bt of the coil end wires 14a and 14b. The non-soldered turn portions 14at1 and 14bt1 of the turns are absorbed by the coil end wire 14 at the end of the thin secondary coil 14.
Disconnection can be prevented from occurring at a and 14b.

Accordingly, the secondary coil bobbin 13 is formed of a thermoplastic resin, a thermosetting resin is used as the casting resin 19, and even if the two resins have different coefficients of thermal expansion, the secondary coil bobbin 13 is formed.
4 can be prevented from breaking at the portions of the terminal fittings 15a, 15b that are connected to the soldering portions 18a, 18b.

The terminal wire winding portions 14a of the terminal wires 14a, 14b on the outer periphery of the terminal metal fittings 15a, 15b.
Non-soldering turn part 1 on the bobbin 13 side of t, 14 bt
When 4at1 and 14bt1 are provided, when the solder bath is used at the time of soldering, the bobbin 13 can be soldered at a place slightly away from the solder surface of the solder bath, so that there is an advantage that the workability is improved.

The present invention is not limited to an ignition coil of the type shown in FIG. 1, but is applied to an ignition coil of the type in which poles 20 are provided at both ends of an iron core 2 as shown in FIG. Can be similarly applied.

[0022]

As described above, according to the ignition coil for an internal combustion engine according to the present invention, the following excellent effects can be obtained.

In the present invention, the coil terminal wire at the end of the secondary coil is wound around the outer periphery of the terminal supported by the secondary coil bobbin with a required number of turns. Since a plurality of turns on the outer periphery of the secondary coil bobbin connected to the secondary coil are left as non-soldering turn portions, and the turn portion on the tip end is connected by soldering to the terminal fitting, the terminal fitting of the coil terminal wire is wound. A plurality of turns of the non-soldering turn portion of the turn portion act as an expansion and contraction portion of the coil end wire, and therefore, due to a difference in expansion coefficient between the bobbin molding resin and the casting resin, pulling and pressing along the terminal fittings. Is generated, the stress is absorbed by a plurality of turns of the non-soldering turns in the windings of the terminal fittings of the coil end wire, and the coil end wire of the thin secondary coil is soldered. It is possible to prevent the disconnection in the vicinity of.

Therefore, according to the present invention, the secondary coil bobbin as a support for the terminal fitting is formed of a thermoplastic resin,
Using a thermosetting resin as the casting resin, it is possible to prevent the terminal wire of the secondary coil from breaking at a portion connected to the soldering portion of the terminal fitting even if the two resins have different coefficients of thermal expansion. .

Further, when a non-soldering turn portion is provided on the bobbin side of the terminal fitting winding portion of the terminal wire on the outer periphery of the terminal fitting as in the present invention, the bobbin can be removed when a solder bath is used at the time of soldering. Since soldering can be performed at a place slightly away from the solder surface of the solder bath, there is an advantage that workability is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of an ignition coil for an internal combustion engine according to the present invention.

FIG. 2 is a longitudinal sectional view of the ignition coil for an internal combustion engine shown in FIG.

FIG. 3 is a perspective view of a main part of an embodiment of an ignition coil for an internal combustion engine according to the present invention.

FIG. 4 is a perspective view of another embodiment of the ignition coil for an internal combustion engine according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2 Iron core 3 Primary coil bobbin 3a, 3b Flange 4 Primary coil 5 Low voltage connector 6 High voltage connector 7, 8 Terminal fitting 9 Low voltage cord 10 Connector 11 High voltage cord 11a Core wire 13 Secondary coil bobbin 13a, 13b Flange 14 Secondary coil 14a Coil terminal wire 14at Terminal part winding part 14at1 Non-soldering turn part 14at2 Tip turn part 14b Coil terminal wire 14bt Terminal part winding part 14bt1 Non-soldering turn part 14bt2 Tip part turn part 15a, 15b Terminal part 16 Coil assembly 17 Solder 18a, 18b Solder 19 Cast resin 20 poles

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01F 31/00-39/00

Claims (4)

(57) [Claims] An iron core is disposed in a case, and a coil assembly including a primary coil wound around a primary coil bobbin and a secondary coil wound around a secondary coil bobbin is fitted around the outer periphery of the iron core. The coil terminal wire at the end of the coil is soldered and connected to a terminal fitting, and the coil assembly is molded with a casting resin filled in the case including the soldered connection portion of the coil terminal wire. In the ignition coil for an internal combustion engine, a coil terminal wire at the end of the secondary coil is wound around the outer periphery of the terminal metal supported on the secondary coil bobbin with a required number of turns, and the terminal metal of the coil terminal wire is wound. The turning portion has a plurality of turns on the side connected to the secondary coil on the outer periphery of the secondary coil bobbin as a non-soldering turn portion, and a tip turning portion is soldered to the terminal fitting. Ignition coil, characterized in that it is. 2. The internal combustion engine according to claim 1, wherein the terminal fitting for soldering and connecting a coil terminal wire at an end of the secondary coil is fixed to a flange of the secondary coil bobbin. Ignition coil. 3. The ignition coil according to claim 1, wherein the casting resin is a thermosetting resin. 4. The ignition coil according to claim 1, wherein the secondary coil bobbin is formed of a thermoplastic resin.