JPH0347319Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an ignition coil for igniting and driving internal combustion engines of various vehicles, and particularly relates to improvements in the assembly structure of a closed magnetic path type ignition coil.

<Prior Art> FIG. 2 shows the assembled structure of a closed magnetic circuit type ignition coil 30 that has been conventionally adopted by the present applicant, and the assembly process is as follows.

First, the bobbin 32 around which the primary winding 31 is wound and the bobbin 34 around which the secondary winding 33 is wound are concentrically combined and then housed in the case 35. At this time, the flange 36 at one axial end of the inner bobbin 32
The fitting part 37 is opened in the corresponding wall part of the case 35.
Try to get it close together.

Next, a suitable resin material 38 such as epoxy is vacuum-cast into the case 35 and cured to physically hold both bobbin structures within the case 35 and ensure insulation. Of course, each bobbin 32, 34 and case 35 are made of an appropriate insulating material such as synthetic resin, and
In an appropriate step before the resin impregnation, one end of the secondary winding 33 is electrically connected to the high voltage terminal 39.

After that, one end of each of the pair of core parts 40 and 41 is inserted in the axial direction into the central axial through hole 44 of the inner bobbin 32 around which the primary winding 31 is wound. In order to prevent this, an insulating spacer 42 is always inserted between the abutting ends to obtain a specified gap.

While maintaining this state, an adhesive 43 is filled between the wall of the through hole 44 of the bobbin 32 and each of the core parts 40 and 41 inserted into the through hole 44 to prevent play, and the adhesive 43 is heated and cured. By doing so, a closed magnetic path type ignition coil is completed.

The core parts 40 and 41 are of course made of a laminated structure of a suitable magnetic material, preferably a high permeability magnetic material such as a silicon steel plate, and the other mating end on the outside of the case is usually welded or otherwise. It is electrically and mechanically fixed using this method, thereby forming a closed magnetic path.

<Problems to be solved by the invention> As seen in the above conventional example, the conventional assembly structure of this type of closed magnetic circuit ignition coil has a relatively large number of parts, is time-consuming, and requires manufacturing precision. be done.

First of all, when inserting the mating ends of each core part 40, 41 into the central through hole 44 of the inner bobbin 32 around which the primary winding 31 is wound, a spacer is used to ensure a specified gap between them. The work of inserting the 42 was actually extremely inefficient.

Further, it is necessary to fill the adhesive 43 into the through hole 44 of the bobbin 32 in order to prevent the core from rattling, and this heating and curing process requires a considerable amount of labor and time.

Furthermore, it is troublesome to tightly fit the flange 36 at one end of the inner bobbin 32 into the fitting part 37 of the corresponding case, and dimensional tolerances regarding these fitting relationships must be kept small in terms of design and manufacturing. It didn't happen. Otherwise, problems such as the resin material 38 to be vacuum impregnated may start to wet out.

However, as recognized in Japanese Utility Model Application Publication No. 60-912, etc., if the ignition coil is of a type in which the core is insert molded integrally with the resin case, instead of the above-mentioned spacer, it is necessary to use a case molding material during the insert molding. By pouring the resin into the gap, there is no need for a separate spacer.

However, there are types of ignition coils that do not use insert molding, that is, types where the core part that protrudes outside the case is exposed, or types where the core is fixed by a fixing method other than embedding into the case. Ignition coils are expected to be in high demand not only now but also in the future, and of course the above-mentioned spacer problems and inner bobbin positioning problems will inevitably occur with such coils.

Considering the assembly structure of the conventional closed magnetic circuit type ignition coil, the present invention aims to simplify the assembly structure and reduce the number of parts, and includes a spacer, which is a separate part inserted between a pair of core parts. The present invention aims to provide a closed magnetic circuit type ignition coil with a new assembly structure that eliminates the need for the use of adhesive, which is required for physically fixing each core part. be.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides a closed magnetic path type ignition coil having the following configuration.

a pair of core parts whose ends abut each other to form a closed magnetic path; an axial through hole in the center for inserting one end of at least one of the core parts, and a primary winding wound therein; a first insulating bobbin arranged concentrically with respect to the first insulating bobbin;
a second insulating bobbin around which a secondary winding is wound; an insulating case for housing the first and second bobbin structures and impregnated with resin; provided as a part of the wall of the insulating case; and a boss-like portion that fits into the through-hole of the first insulating bobbin halfway along its axial length; the upper surface portion of the boss-like portion fits into the through-hole of the first insulating bobbin. A predetermined gap is inserted between one end of one core part inserted into the through hole of the first insulating bobbin and one end part of the other core part opposing thereto. 1. A closed magnetic circuit type ignition coil comprising: a spacer wall portion for ensuring that the boss-like portion has a spacer wall portion; and an outer circumferential surface of the boss-like portion forming a positioning means into which the first insulating bobbin is fitted.

<Functions and Effects> According to the present invention, the boss-shaped portion that is integrally formed on the insulating case itself that houses the first and second bobbins around which the primary and secondary windings are wound is A portion thereof has a spacer wall portion corresponding to a spacer that was required separately in the past.

Therefore, not only can the spacer, which has heretofore been a separate component, become unnecessary, but also the troublesome assembly process associated therewith can be omitted.

In addition, the spacer wall is used to close the through hole for inserting the core, which was conventionally passed through the inside of the case to allow the bobbin to pass through. The bottom wall can have a completely closed design throughout.

Therefore, even when the bobbin structure inside the case is impregnated with resin, the inconvenience of the resin leaking out can be fundamentally solved, and the tight tolerances regarding the fit between the bobbin and the case in design and manufacturing can be eliminated. It will also be released from

Moreover, if the case wall (bottom wall) and the boss-shaped part having the spacer wall are integrally molded as part of the case as described above, each bobbin will be completely inserted into the case. ,on the other hand,
Since one end of at least one of the core parts is inserted into a through hole with a closed bottom, the resin impregnation process for each bobbin also involves the physics of the core part inserted into this bobbin. It is also a process for permanent fixation.

Therefore, it is possible to see the completion of the product without having to undergo a separate fixing process of the core part by a separate heat curing process using a separate adhesive as in the past.

Furthermore, the fact that the case wall and spacer wall can be integral means that there is no room for a space between them in principle, so the creepage distance is sufficiently long in terms of electrical or insulation properties. It also has the effect of being harvestable.

In addition, the height position of the spacer wall, that is, the position where the ends of the pair of core parts meet, is determined by the axial length within the bobbin hole, since this spacer wall is configured as the upper surface of the boss-shaped part. Therefore, the outer circumferential surface of the boss-shaped portion serves as a positioning means for fitting the inner bobbin into the case.

Simply put, by simply placing the inner bobbin in the case so that the axial through hole of the inner bobbin fits around the boss, the bobbin can be automatically positioned, and work efficiency is greatly improved.

In any case, as described above, according to the present invention, it is possible to obtain an extremely rational assembly structure of this type of closed magnetic circuit type ignition coil that requires few parts and simple steps.

<Example> Fig. 1 shows a closed magnetic circuit type ignition coil 1 according to the present invention.
One preferred embodiment of 0 is shown.

First, to explain the static configuration completed as a product, there is a first insulating bobbin 12 around which a primary winding 11 is wound. Winding wire 13
The bobbin structure consists of a second insulating bobbin 14 wound with a case 1 made of a suitable synthetic resin.
It is contained within 5. Like the case, each bobbin 12, 14 may be made of a suitable synthetic resin.

The case 15 has a case wall portion 17 located on the lower side in the figure, and this case wall portion 17 is referred to as a bottom wall portion herein. This case bottom wall 17
The bobbin structure housed inside the case, especially the inner peripheral surface of the through hole 22 provided in the center of the first bobbin 12 on the inside where the primary winding 11 is wound in the axial direction, is It integrally has a boss-shaped portion 23 that fits into the boss-shaped portion 23.
The upper surface of the spacer wall 16 constitutes a spacer wall portion 16, which will be described in detail later.

The pair of core parts 20 and 21 are each preferably constructed of a laminated structure of high magnetic permeability material plates such as silicon steel plates, and are each C-shaped as a whole, but the legs are alternately long and short. In the illustrated case, the right leg of the core section 20 shown on the upper side is longer than the left leg, and the end of this longer leg enters the central through hole 22 of the first bobbin 12. , its end portion faces the upper surface of the spacer wall portion 16.

The end of the short leg of the first core part 20 is fixed to the long end of the second core part 21 by welding, while the end of the short leg of the second core part 21 goes around the outside of the case wall 17 of the case 15, enters the inside of the boss-shaped portion 23, and then faces the lower side of the spacer wall 16.

It is therefore understood that the spacer wall 1
The thickness of 6 defines the gap size that should be placed between the ends of the pair of core parts 20 and 21.

A suitable synthetic resin 18 such as an epoxy resin is poured into the inside of the case 15 and then thermally cured.
As a result, while physically holding the bobbin structure inside the case and ensuring insulation, the resin also surrounds the longer leg of the core section 20 located on the upper side in the figure that has entered the case. Since it is hardened in this way, it is possible to mechanically support the core parts 20 and 21 with this alone.

In fact, the second core part 21 whose other end on the outside of the case is welded and fixed to the first core part 20 and whose other end is inserted from below into the boss-shaped part 23 as described above, A product is completed in which the boss-shaped portion 23 is maintained in a mechanically fixed state without the use of a separate adhesive.

Note that at an appropriate process step before resin casting, one end of the secondary winding 13 is connected to the high voltage terminal 19, and the other end is generally connected to ground potential (vehicle ground potential), although not particularly shown. It is being Of course, the wiring terminals etc. to the primary winding 11 are also the same as before.
It has been taken out.

However, the ignition coil 10 of the present invention,
If you consider the assembly process, you will understand how much simpler the ignition coil 30 is compared to the conventional ignition coil 30 described above.

First, the first bobbin 1 around which the primary winding 11 is wound
In this embodiment, in order to fit the second bobbin 14 around which the secondary winding 13 is wound, the second bobbin structure is placed in a predetermined position in the case 15. The central through hole 2 of the first bobbin 12 is formed on the outer periphery of the boss-shaped portion 23 that is integrally molded and rises toward the inside of the case.
The bobbin structure can be attached to a predetermined position within the case 15 by simply dropping the bobbin structure so that the inner circumferential surfaces of the bobbin structure 2 are fitted into the case 15 without requiring any complicated or skilled hands. On the other hand, if the flat bottom 17 of the case is simply used as a spacer 16' without providing the boss-shaped portion 23, as indicated by the reference numeral 16' in FIG.
The above-mentioned rational bobbin positioning effect cannot be obtained.

Once the bobbin structure is housed in the case 15, the pair of core parts 20 and 21 are assembled before the resin 18 is cast.

That is, in this case, the long leg of the first core portion 20 is inserted into the first bobbin 12 from above where the case is open.
is inserted into the central through hole 22 of the spacer, and its end is placed on the upper surface of the spacer wall 16, while the second core part 21
Insert the short legs of the boss into the downward blind hole of the boss-like portion 23, and
The ends that meet on the outside of the case are fixed in advance by existing welding techniques or the like.

After this, a suitable synthetic resin 18 such as epoxy is poured into the case 15 and impregnated into the bobbin structure through a heat curing process, and at the same time, the legs of the first core part 20 fitted into the case are also hardened. It is physically fixed by the resin 18.

Therefore, in other words, the separate process for fixing the core part as in the past can be omitted, saving not only labor and time but also heating energy for heating and curing the adhesive that was separately used. You can also save money.

However, in the above, only the first core part 20 is fixed during resin casting, and then the second core part 21 is fitted so that one end thereof enters the boss-shaped part 23, and the other end enters the boss-shaped part 23. A process of fixing to the open end of one core part 20 by welding or the like may be adopted.

In addition, in the case shown, after resin casting hardens,
In the figure, the upper opening remains unchanged. However, it goes without saying that a lid may be provided to close this opening if necessary.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a preferred embodiment of a closed magnetic path type ignition coil according to the present invention, and FIG. 2 is a schematic diagram of a conventional closed magnetic path type ignition coil. In the figure, 10 is the entire closed magnetic circuit type ignition coil constructed according to the present invention, 11 is the primary winding, and 12
is the first bobbin, 13 is the secondary winding, 14 is the second bobbin, 15 is the case, 16 is the spacer wall, 17 is the case wall (bottom wall), 18 is the impregnating resin, 20,
21 is a core portion forming a closed magnetic path, 22 is a through hole in the center of the bobbin, 23 is a boss-shaped portion, 30 is a conventional closed magnetic path type ignition coil, and 42 is a spacer thereof.

Claims (1)

[Claims for Utility Model Registration] A pair of core parts that form a closed magnetic circuit by abutting their ends against each other; and an axial through hole in the center for inserting one end of at least one of the core parts. a first insulating bobbin around which a primary winding is wound; arranged concentrically with respect to the first insulating bobbin;
a second insulating bobbin around which a secondary winding is wound; an insulating case for housing the first and second bobbin structures and impregnated with resin; provided as a part of the wall of the insulating case; and a boss-like portion that fits into the through-hole of the first insulating bobbin halfway along its axial length; the upper surface portion of the boss-like portion fits into the through-hole of the first insulating bobbin. A predetermined gap is inserted between one end of one core part inserted into the through hole of the first insulating bobbin and one end part of the other core part opposing thereto. 1. A closed magnetic circuit type ignition coil comprising: a spacer wall portion for ensuring that the boss-like portion has a spacer wall portion; and an outer circumferential surface of the boss-like portion forming a positioning means into which the first insulating bobbin is fitted.