JPH0749778Y2 - ignition coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an ignition coil used in an ignition system of an automobile engine.

[Prior Art] FIG. 4 shows an example of a conventional ignition coil. This ignition coil accommodates a primary coil b and a secondary coil c wound around the case a in a case a, and one side of a loop-shaped iron core d passes through the center of the primary coil b. ing. Further, a resin-made iron core cover f is attached to the iron core d in the vicinity of the high-pressure tower e protruding from the case a.

Further, Japanese Utility Model Laid-Open No. 62-177015 discloses an open magnetic circuit type projecting portion of the I-shaped iron core penetrating the primary coil bobbin, in which only the side surface on the high voltage tower side is provided with an iron core cover. .

[Problems to be Solved by the Invention] By providing the iron core cover f in this way, the distance between the iron core d and the high-pressure tower e can be reduced, and the entire size can be made compact. However, since this structure requires a separate iron core cover f, the number of parts and the number of assembling steps increase accordingly.

Further, in the case where the iron core cover is provided only on the limited side surface of the iron core as in Japanese Utility Model Laid-Open No. 62-177015, the linear distance between the projecting end of the iron core and the high voltage tower can be shortened too much. As a result, it is difficult to make the entire ignition coil compact. Further, it is also desired to form an air gap in a closed magnetic circuit type iron core.

Then, the objective of this invention is providing the ignition coil which can solve such a various point.

[Means for Solving the Problems] In order to solve the above problems, an ignition coil according to the present invention is a first coil that forms a loop by combining with a primary coil and a secondary coil wound around the primary coil. An iron core and a second iron core, and a high-voltage tower to which a secondary coil is connected are provided, and the first iron core penetrates through the bobbin of the primary coil, and the first iron core forms a protruding end part that partially protrudes from the primary coil. In a closed magnetic circuit type ignition coil in which a high voltage tower is provided adjacent to a projecting end, a projecting end of the first iron core is fitted into an iron core cover formed integrally with the primary coil bobbin in a substantially cylindrical shape. In addition, the second iron core is connected to the projecting end portion of the first iron core through the iron core cover, and the thickness of the iron core cover forms an air gap between the second iron core and the first iron core. Characterized by forming And

[Operation of the Invention] When assembling the ignition coil of the closed magnetic circuit type according to the present invention, when one arm portion of the first iron core is passed through the primary coil bobbin, the projecting end portion thereof integrally projects with the end portion of the primary coil bobbin. Since it is housed in the formed tubular core cover, the entire projecting portion is covered with the core cover. Therefore, it is possible to reduce both the number of parts and the number of steps for mounting the core cover, which are conventionally separate bodies.

Moreover, the linear distance between adjacent high-voltage towers can be shortened,
As a result, the entire ignition coil can be made compact.

Further, a second core is provided between the ends of the first core via an iron core cover.
Since the iron core is provided, a predetermined air gap can be reliably formed between the end portions of the iron core due to the thickness of the iron core cover, which is a preferable structure for the closed magnetic circuit type iron core.

[Embodiment] FIGS. 1 to 3 show an embodiment of the present invention. This ignition coil is used for an engine ignition system of an automobile, and a through hole 3 is formed in a bottom portion 2 of a resin case 1 (see FIG. 2), and a part of the side portion thereof is formed. The protrusion 4 protruding outward is integrally formed, and the high-pressure tower 5 is formed therein.

A coil assembly 8 including a primary coil 6 and a secondary coil 7 wound around the primary coil 6 is accommodated in the bottom portion 2 of the case 1. In addition, a projecting end portion 9a which is one end portion of the first iron core 9 which is a C-shaped iron core is inserted into the through hole 3. The projecting end 9a projects to the opposite side of the case 1 and fits into the iron core cover 10 made of insulating resin. A second iron core 11 that is an I-shaped iron core is provided between the iron core cover 10 and the other end 9b of the first iron core 9.
Are fitted. A predetermined air gap is formed between the protruding end portion 9a and the second iron core 11 by the thickness of the iron core cover 10.

The iron core cover 10 has a substantially cylindrical shape and is integrally formed on the top of the primary coil bobbin 12 around which the primary coil 6 is wound. As shown in FIG. 3, a hole 13 is formed in the center of the primary coil bobbin 12 for allowing the protruding end 9a of the first iron core 9 to pass therethrough. The hole 13 penetrates the central portion of the primary coil bobbin 12 in the vertical direction, and the upper end portion thereof reaches the inside of the iron core cover 10 and forms a space having a shape capable of accommodating the projecting end portion 9a therein. The hole 13 can be aligned with the through hole 3 of the case 1.

On the other hand, the secondary coil 7 is formed by winding a conductive wire around the secondary coil bobbin 14, and as shown in FIG. 3, an opening for accommodating the primary coil bobbin 12 is formed in the center of the secondary coil bobbin 14. A portion 15 is formed, and a projecting portion 16 that can be fitted into the protrusion 4 is formed at the upper end portion, and a high voltage terminal 17 is provided therein.

In order to assemble this ignition coil, first, as shown in FIG. 3, the iron core cover 10 side of the primary coil 6 is inserted into the opening 15 from the bottom of the secondary coil bobbin 14 (the side opposite to the overhang 16). When fitted to, the coil cover 8 (see FIG. 2) in which the iron core cover 10 and the core cover 10 are integrated with each other is formed with the core cover 10 protruding toward the protruding portion 16 side.

Therefore, as shown in FIG. 2, the coil assembly 8 is put in the case 1. Then, the hole 13 of the primary coil bobbin 12
Corresponds to the through hole 3 of the case 1, so that the protruding end portion 9a of the first iron core 9 is fitted into the hole 13 from the through hole 3. The protruding end 9a penetrates through the primary coil bobbin 12 and
It is fitted inside and the whole is covered with the iron core cover 10. At the same time, the other end 9b side faces the iron core cover 10 outside the case 1. Therefore, the second iron core 11 is fitted between the iron core cover 10 and the other end portion 9b and fixed by an appropriate method such as coating with a resin.

The ignition coil thus formed has a protruding end portion.
9a is placed close to the high-voltage tower 5 and the distance L is required to obtain the creepage distance required when the iron core cover 10 is not present.
Although the distance is as follows, the presence of the iron core cover 10 effectively insulates the two.

Moreover, since the entire projecting end 9a is covered by the tubular core cover 10, the straight line distance 1 between the projecting end 9a and the high-voltage tower 5 is the same as when the core cover is used so that a part of the core is exposed. Compared with this, since the length can be made shorter, the entire ignition coil can be made more compact.

Further, since the iron core cover 10 is integrated with the primary coil bobbin 12, the end of the protruding end portion 9a can be covered with the iron core cover 10 only by fitting the protruding end portion 9a to the primary coil bobbin 12, thus reducing the number of work steps. Not only you can do it, but also iron core cover
The number of parts can be reduced compared to the case where 10 is a separate body.

Moreover, when assembling the ignition coil, a predetermined air gap is reliably formed by the wall thickness of the iron core cover 10 between the projecting end portion 9a of the first iron core 9 and the second iron core 11, so that the closed magnetic circuit type A preferable structure for the iron core can be easily obtained.

[Effect of the Invention] The closed magnetic circuit type ignition coil according to the present invention is provided with the iron core cover integrally with the primary coil bobbin. Therefore, the number of parts and the number of man-hours for mounting the iron core cover, which is a separate body, are required. Both can be reduced.

Moreover, since the iron core cover has a substantially cylindrical shape and covers the entire circumferential surface of the protruding end of the first iron core, the linear distance between the protruding end and the high-voltage tower can be further shortened, and as a result, the entire ignition coil can be made compact. You can

Furthermore, since the iron core is assembled by sandwiching the iron core cover between one end of the first iron core and one end of the second iron core, an air gap corresponding to the thickness of the iron core cover is reliably formed between the iron core ends. can do. As a result, it is possible to easily obtain a preferable iron core structure in the closed magnetic circuit type ignition coil.

[Brief description of drawings]

1 to 3 show an embodiment, FIG. 1 is an external side view, FIG. 2 is an exploded perspective view of an essential part, and FIG. 3 is an exploded perspective view of an essential part with a part cut away. FIG. 4 is a side view of a conventional example with its periphery broken. (Description of symbols) 1 ... Case, 5 ... High-voltage tower, 6 ... Primary coil,
7 ... secondary coil, 9 ... first iron core, 10 ... iron core cover, 11 ... second iron core, 12 ... primary coil bobbin.

Claims (1)

[Scope of utility model registration request] 1. A primary coil and a secondary coil wound around the primary coil, a first iron core and a second iron core that form a loop by combining them, and a high-voltage tower to which the secondary coil is connected. An ignition coil of a closed magnetic circuit type, which comprises a protruding end part of the first core that penetrates the bobbin of the primary coil and partially protrudes from the primary coil, and a high-voltage tower is provided adjacent to the protruding end part. In the above, the protruding end portion of the first iron core is fitted into the iron core cover that is integrally formed with the primary coil bobbin so as to project in a substantially cylindrical shape, and the second iron core is inserted into the first core through the iron core cover. The ignition coil, which is connected to the projecting end of the core, and has an air gap formed between the second core and the first core due to the thickness of the core cover.