JPH0440257Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to an ignition coil for an internal combustion engine.

(Prior Art) Conventional ignition coils are generally made by injecting and hardening a casting resin into a case that houses primary and secondary coils arranged around the outer periphery of a core. A cylindrical part for the high voltage cord was formed at the bottom of the case, and the low voltage terminal was generally taken out from the open end of the case (for example, Nippon Denso Technical Report, Reference number 31-094, July 1983). Published on the 20th).

However, in the conventional device described above, the low-voltage terminal protrudes from the open end of the case, which not only results in poor waterproofness, but also makes it difficult for the high-voltage cord tube and the low-voltage terminal to connect to the bottom of the case and the open end. Since they protrude more in opposite directions, there is a problem that the axial length becomes longer and the overall physique becomes larger.

(Problems to be Solved by the Invention) Therefore, the present invention has excellent waterproof properties and has a smaller overall size.

(Means for solving the problem) Therefore, in the present invention, a core and primary and secondary coils arranged around the core are housed in a case,
In the ignition coil for an internal combustion engine, which is made by injecting and hardening a cast resin into the case, a board equipped with a control circuit section for intermittent primary current of the ignition coil is also housed in the case, and is attached to the bottom wall of the case. A cylindrical part of a high voltage cord and a connector part for a low voltage side terminal are integrally formed, and the low voltage side terminal is fixed to the board, and this terminal is placed from inside the case into the connector part for the low voltage side terminal, and the base of the terminal is A bushing for sealing between the inside of the connector part and the inside of the case is attached to the outer periphery of the connector part, and a ring-shaped fold is integrally formed on the outer periphery of this bushing, and this bushing is attached to the connector part for the low voltage terminal. The present invention provides an ignition coil for an internal combustion engine that is press-fitted into a through hole formed in communication with the inside of the case.

(Function) As a result, the connector part for the low voltage side terminal integrally formed on the bottom wall of the case prevents moisture from adhering to the low voltage terminal, and the sealing member improves sealing performance, and the cylindrical part for the high voltage cord and the low voltage By forming both the side terminal connector portion and the side terminal connector portion on the bottom wall of the case, the overall axial length is shortened.

(Example) An example of the present invention shown in the drawings will be described below. In Fig. 1, 1 is a cylindrical 1 made of synthetic resin.
A lid portion 1a is integrally provided at the tip of the next bobbin. Further, a large diameter portion (stopper portion) 1b is formed in the primary bobbin 1 adjacent to the lid portion 1a, and a recess for winding is formed on the outer periphery of the intermediate portion of the primary bobbin 1 adjacent to the large diameter portion 1b. 1c is formed, and the primary coil 2 is wound in this winding recess 1c. Further, the other end of the primary bobbin 1 is an open end. Reference numeral 3 denotes a synthetic resin secondary bobbin having a plurality of winding grooves formed on its outer periphery, which is arranged on the outer periphery of the primary bobbin 1, and a secondary coil 4 is wound in segments around the outer periphery of the winding grooves. Further, a lid portion 3a is formed at one end of the secondary bobbin 3.
A core positioning protrusion 3b that protrudes axially into the primary bobbin 1 is integrally formed at the center of the inner bottom surface of a, and a terminal fixing protrusion 3c is integrally formed on the outside of the lid part 3b. There is. A secondary terminal 5 is fixed to the terminal fixing projection 3c, and has a threaded portion 5a to which the high-voltage end of the secondary coil 4 is connected and a high-voltage cord is connected. Reference numeral 6 denotes a synthetic resin case, in which a partition wall 6a is integrally formed to partition the ignition coil side and the control circuit side, and a mounting stay 6b is integrally formed on the outer wall. Furthermore, a connector part 6c for a low voltage side terminal and a cylindrical part 6d for a high voltage cord are integrally formed on the bottom wall in communication with the inside of the case 6.
a is disposed to protrude within the high voltage cord cylindrical portion 6d. Reference numeral 7 denotes a thermosetting resin which is evacuated and injected into the case 6 and then cured. 8 is approximately the same diameter as the inner diameter of the secondary bobbin 16 (a slightly smaller diameter is better), and is about 1 mm longer than the dimension from the inner surface of the lid 1a of the primary bobbin 1 to the tip of the core positioning protrusion 3b of the secondary bobbin 3. It is a cylindrical core with a shorter length and is inserted inside the primary bobbin 1.

In addition, the core positioning protrusion 3b of the secondary bobbin 3
is in contact with the side surface of the core 8, and the core 8 and the primary bobbin 1 are shifted in the axial direction with respect to the secondary bobbin 3. The distance between the core 8 and the primary coil 2 is set so that a sufficient withstand voltage can be obtained even when downsized.

Reference numeral 9 denotes a control circuit section for intermittent current flowing through the primary coil 2 of the ignition coil, and is housed in the case 6 separated from the ignition coil side via a partition wall 6a.
Reference numeral 13 designates a printed circuit board on which each electric circuit component of the control circuit section 9 is mounted, and reference numeral 14 designates a low voltage side terminal which is press-fitted and fixed to the printed circuit board 13 and is disposed within the low voltage side terminal connector section 6c.

Reference numeral 15 denotes a bush made of an elastic material such as rubber attached to the outer periphery of the base side of the terminal 14.As shown in FIG. is provided with a hole 15b through which the terminal 14 passes tightly. The bush 15 is press-fitted into a circular hole 6e formed at the base of the low-voltage side terminal connector portion 6c so as to communicate with the inside of the case 6.

Here, a pleat 15a is formed on the outer periphery of the bush 15, which is press-fitted into a circular hole 6e at the bottom of the case 6.
Since the folds 15a are provided, the space between the case 6 and the connector portion 6c is sealed.

In the above configuration, the casting resin 7 is injected into the case 6 from the open end side of the case 6 and hardened. At this time, in the above configuration, due to the presence of the bush 15, there is no leakage of the casting resin 7 from the bottom of the case 6.

(Effects of the invention) As described above, in this invention, the connector part for the low voltage side terminal integrally formed on the bottom wall of the case makes it difficult for moisture to adhere to the low voltage side terminal, and sufficient waterproofness can be obtained. At the same time, since the terminal with a bushing attached to the outer periphery of the base is fixed to the circuit board, the low voltage side terminal can be connected by storing the circuit board equipped with the control circuit section that intermittents the ignition coil primary current in the ignition coil case. Not only can it be easily placed inside the connector part for the low-voltage side terminal from inside the case, but at the same time, the ring-shaped folds integrally formed on the outer periphery of the bush attached to the outer periphery of the root part of the terminal allow it to be placed inside the connector part. It is possible to reliably seal between the inside of the case and the inside of the case, and reliably prevents the molding resin from leaking from the bottom wall of the case when the molding resin is injected into the case from the open end of the case and cured. In addition, the case houses not only the ignition coil winding section but also a board equipped with a control circuit that intermittents the primary current of the ignition coil, and a tube for the high voltage cord. By forming both the connector part and the low voltage side terminal connector part on the bottom wall of the case, there is an excellent effect that the overall size can be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the coil of the present invention, and FIGS. 2a and 2b are a perspective view and a side view showing a bush in the above embodiment. 2...Primary coil, 4...Secondary coil, 6...
Case, 6c...Connector part for low pressure side terminal, 6d...Cylinder part for high voltage cord, 7...Thermosetting resin forming casting resin, 8...Core, 14...Low pressure side terminal, 15...Seal The parts that make up the parts.

Claims (1)

[Scope of utility model registration request] In an ignition coil for an internal combustion engine, a core and primary and secondary coils arranged around the core are housed in a case, and a cast resin is injected and hardened into the case, and the primary current of the ignition coil is intermittent. A board with a control circuit mounted thereon is also housed in the case, a high voltage cord cylindrical part and a connector part for a low voltage side terminal are integrally formed on the bottom wall of this case, and the low voltage side terminal is fixed to the board. At the same time, this terminal is placed inside the low voltage side terminal connector part from inside the case, and a bushing for sealing between the inside of the connector part and the inside of the case is attached to the outer periphery of the root part of this terminal, and furthermore, this terminal An ignition coil for an internal combustion engine, in which a ring-shaped pleat is integrally formed on the outer periphery, and the bushing is press-fitted into a through hole formed in the low-pressure side terminal connector part so as to communicate with the inside of the case.