DE2514107A1 - IGNITION COIL FOR COMBUSTION ENGINES, ENCLOSED IN INSULATING RESIN - Google Patents

Description

Fabbrica Italiana magnet! Marelli S.p.A., Via Guastalla 2,

I-iilano

Ignition coil for internal combustion engines, encapsulated in insulating synthetic resin.

The present invention relates to an ignition coil for internal combustion engines, encapsulated in insulating synthetic resin.

It is known that in this type of coils the two superimposed windings, the sealing capsule made of insulating material and, if necessary, the iron core magnet . embedded in an insulating resin.

The H _a rz is the Z _w corner of the insulation of the turns with one another, the mounting of the individual winding layers and the discharge of heat to the outside.

Typically, these coils are impregnated with polyester resin in an autoclave under vacuum and then cooked with epoxy resins in special molds in the manufacturing process, which give the coil the final F _o rm, after the resin has hardened.

These coils are available as a compact unit which is externally protected by a resin layer and therefore do not require a container.

Because the parts are held in the resin, there is no risk of breakage in the winding wires and these coils are therefore suitable especially good for motor boating, car racing and

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similar purposes where the vehicles are exposed to strong vibrations.

These coils were previously designed with a closed magnetic circuit, where the primary winding, which is subject to the greatest heating, is within the secondary winding - i.e. below the most unfavorable conditions for effective heat dissipation outwards - is arranged.

In order to remedy this deficiency, a resistor had to be provided which was connected in parallel with the primary winding and is located outside the coil; this may have solved the problem of heat dissipation from the coil, but the Manufacturing costs increased due to the arrangement of the resistor. Nevertheless, the known coils result because of their Training very limited services, which in no way can be compared with those of the usual oil coils with an open magnetic circuit are.

The object of the present invention is to provide an insulating resin-embedded coil which eliminates the need for a resistor power, has excellent heat dissipation and gives good performance. Another object of the invention is in creating a coil that uses the same components and a large part of the facilities to manufacture it on v / eist that can be used for the usual oil spools.

The coil according to the invention is characterized in that it has an open magnetic circuit, the core of which is only protrudes from the windings on the side on which the insulating capsule is located, and on the outside around the finished one Coil a sheath made of ferromagnetic !!! Material is provided. An ideal derivation is made by means of the open magnetic circuit the heat is ensured in that the primary winding comes to lie outside the secondary winding, which

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more stringent conditions for effective cooling can be achieved «Dar.iit the use of a resistor becomes superfluous »

With the core protruding only on the side of the lid, the following advantages are achieved:

a) easier arrangement of the windings on the cages when inserting into the autoclave for pre-impregnation with Polyester resins;

b) Possibility of arranging and holding the core inside the windings during the pre-impregnation in question, in contrast to the known systems, which the later assembly of the core, for example on the occasion the insertion of the coil, provide;

c) Eliminate the causes that cause the cracks or fissures

in the resin during hardening in the mold. During this process, the resin does not have any contact with the metal parts that form the magnetic circuit, parts that would cause these cracks due to their different coefficient of thermal expansion than the resin material, especially around the coil or at the bottom of the same, where a greater thickness is used for insulation reasons _O

When the jacket is attached to the outside of the coil, which is completed, i.e. has already been in the resin bath, it complements each other the magnetic circuit without affecting the manufacturing process of the coil and the shrinkage of the resin.

In the case of recourse in a certain way to the invention Coil on the construction of the oil coils can advantageously have the same components (jacket, core, Windings and cover) used v / earth, which with the conventional Coils can be used, as can the tools for the most part. The arrangement of the coil on Vehicle chassis is done by means of a bracket that covers the coat

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and the coil comprises any material and any Can be form because it does not contribute to the formation of the magnetic circuit.

Accordingly, a bracket such as that used for oil spools can also be used is common.

The further advantages of the invention emerge from the following Description and the attached drawings, which are based on a preferred embodiment of the coil.

Fig. 1 shows in longitudinal section the winding and the Coil core after impregnation in an autoclave under vacuum with polyester resin;

Fig. 2 illustrates in perspective and partially in longitudinal section the finished coil (according to the Impregnation with synthetic resin).

In the figures, the reference number 1 denotes the primary winding, which is located in the outer region of the coil; with the secondary winding located within the primary winding is designated. The ferromagnetic K _e rn 3 consists of slats.

According to the invention, the core 3 is moved all the way to the upper part (cover side) of the coil, so that it is on the other Side cannot protrude beyond the ends of the windings »

With this arrangement, the, b under the preceding point a)), and c) listed advantages achieved _Q

In FIG. 2, the insulating capsule is provided with the reference numeral 4 · described which carries the low-voltage terminals 5-6 and the high voltage terminal 7, to the secondary winding 2 or the K _e rn 3 is connected.

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With 8 the mass of the insulating synthetic resin is referred to, which encloses the windings and the coil its final shape gives.

As can be seen, the resin is in considerable strength both around the side face of the windings and at the bottom the coil provided.

In particular, it can be seen how no metal parts of the magnetic circuit are embedded in the resin at the bottom of the coil. This eliminates the risk that cracks can arise in the resin while it is hardening, _{or the like}

The purpose of the resin is electrical insulation, the heat conduction to dissipate the heat in the outer windings and in giving the coil a shape after it solidifies is.

The ferromagnetic jacket 9, which completes the magnetic circuit, is attached to the cylindrical side surface consists of two or more cylindrical half-shells. Their attachment is done after the coil is completed is to ensure the strength of the resin. A collar provided with bracket 10 secures the jacket 9 by means of of the bolt 11 to the bobbin. The bracket also enables the spool to be held on the chassis.

The temple is not part of magnetic circuit and can therefore consist of any W _e rkstoff.

Expectations

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Claims (4)

25U107 claims 1) y In insulating resin embedded ignition coil, in particular for internal combustion engines, characterized in that it comprises an open magnetic circuit, whose K _e rn (3) only at the side of the windings (1, protrudes 2), on which the insulating capsule (4 ) is located, and that a jacket (9) made of ferromagnetic material is provided around the finished coil. 2) Ignition coil according to claim 1, characterized in that the K _e rn (3) represents the high-voltage terminal of the secondary winding and the secondary winding (2) is arranged within the primary winding (1). 3) ignition coil according to claim 1 or 2, characterized in that that the jacket (9) consists of two or more half-shells which have a cylindrical shape and arranged around the hardened resin layer of the coil externally by means of a collar-provided bracket (10) which also allows the coil to be held on the chassis. 4) manufacturing method of a coil according to claim 1, characterized characterized in that the core (3) i ^ i inside the windings (1, 2) during the pre-impregnation process of the coils Resin is placed and fixed in the autoclave. 509842/0755