JPH062658U - Ignition coil for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Object] In an ignition coil with a built-in switching module, the number of steps for connecting one end of the primary coil of the ignition coil and the collector of the switching module is reduced, and reliability is improved. [Structure] The terminal portion 18 is provided integrally with the metal case 11 of the switching module 10 to be built in the ignition coil,
One end of the primary coil 1 is directly connected to this terminal.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an ignition coil which is used for each cylinder of an internal combustion engine and which is used in a low voltage distribution ignition system for supplying a high voltage directly to an ignition plug of each cylinder by a built-in switching module.

[0002]

[Prior art]

 As such an ignition coil, the applicant of the present invention casts an insulating resin into an insulating case, and uses a cured insulating resin layer to fit a primary coil fitted outside the iron core into the insulating case. A utility model in which a secondary coil fitted outside and a switching module electrically connected to both coils are fixed is proposed in Japanese Utility Model Laid-Open No. 4-8419. As shown in FIG. 6, the switching module 10 solders a switch element chip (power transistor chip) 12 on the inner bottom of a shallow dish-shaped metal case 11 and mounts a hybrid integrated circuit (hybrid IC) 13 thereon. The case is closed by filling it with silicone gel and fixing the plastic lid 14 to the open surface of the case. This lid may be omitted.

[0003]

[Problems to be solved by the device]

 In the conventional switching module, in addition to connecting the base lead wire 15 and the emitter lead wire 16 to the hybrid integrated circuit 13 for connecting to an external device, the collector (output) lead wire 17 is soldered to a metal case to It is connected to one end of the coil by soldering, and the above-mentioned base lead wire 15 and emitter lead wire 16 are connected to separate primary terminals provided in an insulating case by soldering. For this reason, the connecting work by soldering the collector lead wire 17 and the electric wire at one end of the primary coil is troublesome, or the connecting portion comes into contact with the base lead wire or the emitter lead wire, or the primary coil There is a problem of low reliability due to the one end and the metal case being connected via the collector lead wire.

[0004]

[Means for Solving the Problems]

 Therefore, in the present invention, one end of the primary coil is directly connected to the metal case of the switching module. Insulating resin is cast into the insulating case, and a hardened insulating resin layer is used to form the insulating case. An ignition coil for an internal combustion engine, in which a primary coil fitted outside an iron core, a secondary coil fitted outside the primary coil, and a switching module electrically connected to both coils are fixed A terminal portion is integrally provided on the metal case of the switching module, and the primary coil is connected to the terminal portion.

[0005]

【Example】

 FIG. 1 shows a switching module 10 used in the present invention, which is different from FIG. 6 in that there is no collector lead wire 17 and the metal case 11 is provided with a terminal portion 18 which is integrally provided during molding. It is that.

In FIGS. 2 to 5, 1 is a primary coil, 2 is a secondary coil, 3 is an iron core partially penetrating the bobbin of the primary coil, and 4 is an insulating case. As shown in FIG. 5, the insulating case 4 is made of a synthetic resin and integrally includes a housing portion 4a for both the primary and secondary coils and a pocket-shaped auxiliary housing portion 6 separated from the housing portion 4a by a wall 5. I have it. Both the housing 4a and the auxiliary housing 6 are open to the open surface of the case, but since the height of the wall 5 is lower than the open surface of the case, an insulating resin, for example, epoxy resin, is cast into the housing 4a. At this time, a part of the resin also enters the auxiliary housing portion 6 and is hardened together to become the insulating resin layer 7.

Further, the insulating case 4 has a holding portion 4b for the high voltage terminal 8 and a holding portion 4c for the low voltage terminal 9, and these terminals 8 and 9 are respectively holding portions 4b and 4c when the insulating case 4 is molded. It is fixed integrally with insert mold. The low-voltage terminal 9 consists of a terminal for connecting the primary coil to the battery of the automobile, a terminal for applying a drop signal from the control unit to the switching module, and a grounding terminal. 2. The connection status of the switching module 10 and the high voltage and low voltage terminals 8 and 9 is shown in the circuit diagram of FIG.

In the illustrated embodiment, since the auxiliary housing portion 6 is directed between the housing portion 4a and the holding portion 4c of the low voltage terminal, the insulating case 4 is molded in the state shown in FIG. Two sets of E-shaped iron cores 3 are used facing each other.

Since a hole for passing the iron core is formed in the center of the bottom of the housing portion 4a, one end of the bobbin of the primary coil is fitted into this hole to fit the primary coil 1 into the housing portion 4a. While standing on the bottom, the secondary coil 2 is concentrically fitted to the outside of the primary coil to accommodate both coils in the accommodation portion 4a, and the auxiliary accommodation portion 6 accommodates the switching module 10. As shown in FIG. 4, one end of the primary coil 1 is soldered to the low-voltage terminal 9 to be supplied with battery voltage, and the base lead wire 15 of the switching module is soldered to the low-voltage terminal 9 to be connected to the external control unit. Upon receiving the ignition signal, the emitter lead wire 16 is soldered to the low voltage terminal 9 so as to be connected to the external ground. Then, the other end of the primary coil is connected to the terminal portion 18 integrally provided in the metal case of the switching module and soldered to connect the output of the switching module to the primary coil.

Insulation resin is vacuum-cast and hardened in the case where wiring is performed in this way, and the primary and secondary coils are housed in the housing 4 a by the insulating resin layer 7, and the switching module is housed in the auxiliary housing 6 Fix each inside and insert the center legs of the two E-shaped iron cores 3 and 3 into the bobbin of the primary coil from the bottom of the case and from the top of the case. Fix along the outside of the side.

Although the illustrated embodiment uses two opposed E-shaped cores, the present invention can also be applied to one that uses one U-shaped core as shown in the previous proposal.

[0012]

[Effect of device]

 As is clear from the above, according to the present invention, since the metal case and the primary coil can be directly connected, the collector lead wire and the soldering part can be omitted, the number of parts can be reduced, and the soldering of the collector lead wire has been conventionally performed. It is possible to solve the problem. Workability is also greatly improved. From the above, according to the present invention, an inexpensive and highly reliable ignition coil can be easily provided.

[Brief description of drawings]

FIG. 1 is a perspective view of a switching module used in the present invention.

FIG. 2 is a perspective view of an ignition coil according to the present invention.

3 is a cross-sectional view of FIG.

FIG. 4 is a plan view showing a wiring state of a coil, a switching module, and a low voltage terminal.

FIG. 5 is a perspective view of an insulating case.

FIG. 6 is a perspective view of a conventional switching module.

FIG. 7 is a circuit diagram of an ignition coil.

[Explanation of symbols]

 1 Primary coil 2 Secondary coil 2 Iron core 4 Insulation case 7 Insulating resin layer 9 Low voltage terminal 10 Switching module 11 Metal case 18 Terminal part

Claims (1)

[Scope of utility model registration request] 1. A primary coil in which an insulating resin is cast into an insulating case and a cured insulating resin layer is fitted into the insulating case outside the iron core, and a secondary coil which is fitted outside the primary coil. In an ignition coil for an internal combustion engine in which a coil and a switching module electrically connected to the coils are fixed, a terminal portion is integrally provided in a metal case of the switching module, and the primary coil is connected to the terminal portion. An ignition coil for an internal combustion engine characterized by the above.