DE102009007396A1 - Secondary coils for ignition coils and their manufacturing process - Google Patents

Abstract

In a method for producing a secondary coil (1) for ignition coils, the following steps are provided: - winding a wire (18) coated with at least one lacquer layer (26) onto a winding mandrel (20) having a longitudinal axis (12) at an angle of at least 20 ° with respect to the longitudinal axis (12) of the winding mandrel (20), - bonding of adjacent turns of the wire (18) by dissolving and curing the lacquer layer (26).

Description

The Erfindng relates to a method for the production of secondary coils for ignition coils according to the preamble of claim 1, and a secondary coil for ignition coils according to the preamble of claim 8.

secondary coils be in ignition coils used. ignition coils further comprise a coil core made of magnetic material, and a primary coil on. For the production of primary and the secondary coil a wire is wound onto a mandrel, leaving the wire is formed into several turns. The secondary coil has many times more turns than the primary coil. The primary coil is connected to a low voltage source. The secondary coil is connected to the high voltage power supply for a spark plug. At a ignition coil is a high voltage by interrupting the current flow in the primary coil circuit in the secondary coil circuit induced.

at secondary coils exists in the prior art, the problem that it is too Corona discharges can come when the voltage difference between two adjacent turns in air is too high. In the past The prior art, the secondary coils are therefore often resin poured, taking care that no air bubbles when casting be included. This is a very elaborate and expensive Method.

alternative becomes the secondary coil, to reduce the risk of corona discharge, in the longitudinal direction for example, arranged concentrically about the longitudinal axis of the coil Slices divided into several chambers. The manufacturing process is also expensive and expensive.

Of the The invention is therefore based on the object secondary coils as well as to provide a method of making secondary coils that simple and cost-effective is and in the secondary coils according to the invention can be produced, which reduces the risk of corona discharge is.

to solution This object is achieved by the features of claims 1 and 8.

• – Wickeln von einem mit mindestens einer Lackschicht beschichteten Draht auf einen eine Längsachse aufweisenden Wickeldorn unter einem Winkel von mindestens 20° in Bezug auf die Längsachse des Wickeldorns und
• – Verkleben von einander angrenzenden Windungen des Drahts durch teilweises Anlösen und anschließendes Aushärten der Lackschicht.

The method for manufacturing a secondary coil for ignition coils comprises the following steps:

• - Winding of a coated with at least one paint layer wire on a longitudinal axis having a winding mandrel at an angle of at least 20 ° with respect to the longitudinal axis of the winding mandrel and
• - Bonding of adjacent turns of the wire by partial dissolution and subsequent curing of the lacquer layer.

The Method has the advantage that the wire at an angle of at least 20 ° in Reference to the longitudinal axis the winding mandrel is wound. The larger the winding angle in relation on the longitudinal axis the winding mandrel is, the less likely it is that corona discharge occurs. This is because the adjacent turns have a lower voltage difference than adjacent ones Turns of a wire wound at an angle less than 20 ° has been. The voltage difference of adjacent turns The present invention is below the corona discharge voltage.

Around To achieve this angle, the adjacent turns become while the winding are glued together. This also means that the turns can not slip off. This also leads In addition, corona discharges can not occur when slipping the turns usually occur.

The dissolve the lacquer layer can by heating the lacquer layer by means of a Heating device triggered become.

The dissolve the lacquer layer can also by applying a solvent triggered on the paint layer become.

The Bonding of the adjacent turns of the wire takes place while of the winding. The bonding of the adjacent turns has the advantage that the coil consisting of the turns self-supporting is.

When Paint layer, a baked enamel layer can be used. When a Baked enamel layer and a big one Winding angle (preferably greater than 20 °) used can, can on adhesive tapes, Potting compound or impregnation within the secondary winding be waived.

Of the To be wound wire can also be coated with two layers of paint be, being as outer lacquer layer a baked enamel layer can be used.

Of the Winding mandrel can be removed after winding from the secondary coil. At the In the prior art, the secondary coil is often applied directly to a secondary coil core and thus wound up on no mandrel and then with the secondary coil core in the ignition coil built-in.

In the present invention, no secondary coil core is used. This has the advantage that by the winding core is removed and no secondary coil core is used, material can be saved. In addition, an ignition coil using a secondary coil without secondary coil core is more compact than an ignition coil using a secondary coil containing a secondary coil core.

The secondary coil can be overmolded after removal of the winding mandrel with plastic. The overmolded plastic provides for the secondary coil electrical insulation to the outside The overmolding with plastic is a simple, inexpensive and time-saving process. additionally must in contrast to the casting Do not care with resin that no air bubbles are trapped become. Even with an inclusion of air bubbles it comes up of the present invention does not lead to corona discharge. It can not just the secondary coil but at the same time the other components that are within the ignition coil are located, such as the primary coil and the primary coil core, be overmoulded with plastic. In this way, the components form inside the ignition coil a solid unit.

at a secondary coil according to the invention for ignition coils, with a longitudinal axis, one concentric about the longitudinal axis wound wire, it is provided that the wound wire at an angle of at least 20 ° with respect to the longitudinal axis is wound, wherein the wire at least one during winding at least partially solvable Paint layer has.

Of the Coiled wire can also be at an angle of at least 25 ° in relation on the longitudinal axis be wound up.

The Lacquer layer may be a baked enamel layer, wherein the baked enamel layer made of polyvinyl butyral, polyamide or epoxy resin can.

The solubilized Paint layer is stickable. A heating device can be the lacquer layer dissolve. Alternatively, a device may apply a solvent to the one Apply varnish-coated wire to dissolve the varnish layer.

Of the To be wound wire can also be coated with two or more paint layers be, with the outer lacquer layer a baked enamel layer can be.

The secondary coil does not have a secondary coil core on. After winding, the winding mandrel is wound onto the secondary coil has been, from the secondary coil away.

The secondary coil without secondary coil core is coatable with plastic. It can not only the secondary coil but also the other components inside the ignition coil are arranged to be extrusion coated with plastic.

in the An embodiment will be described below with reference to the drawings closer to the invention explained.

It show schematically

1 a partial view of a cut pencil ignition coil,

2 a side view of a winding mandrel with already wound wire,

3 a sectional view of the wound wire,

4 a sectional front view of a winding mandrel with wound wire,

5 a plastic-molded secondary coil in the sectional side view.

1 schematically shows a partial section of a pencil ignition coil 3 , A pencil ignition coil 3 can be used for example in an ignition system of a gasoline engine. In an ignition coil, a high voltage is induced in the secondary circuit by interrupting the current flow in the primary circuit. This high voltage is passed in an ignition system of a gasoline engine to the spark gap of a spark plug to ignite the fuel-air mixture in the cylinders of the gasoline engine.

The pencil ignition coil 3 has an upper part 5 on, in which the control electronics is arranged. The control electronics is via a plug 7 connected to a supply voltage.

The pencil ignition coil 3 preferably consists of a cylindrical core 2 , The cylindrical core 2 is preferably made of magnetizable material. Concentric around the cylindrical core 2 around is a secondary coil 1 arranged. The longitudinal axis 13 the secondary coil 1 is identical to the longitudinal axis 15 of the cylindrical core 2 , Concentric around the secondary coil 1 around is a primary coil 6 arranged. The primary coil 6 is on a primary spool core 8th wound. The primary coil 6 may alternatively instead of a primary coil core 8th directly onto a plastic spooled secondary coil 1 be wrapped. The primary coil 6 in turn is concentric with the housing 10 surrounded by the pencil ignition coil. Alternatively, the primary coil 6 concentric around the cylindrical core 2 be arranged around. In this case, then the secondary coil 1 concentric around the primary coil 6 arranged.

The primary coil 6 is via the control electronics and the plug 7 connected to the supply voltage, which is a low-voltage source. By means of the control electronics, the current flow in the primary coil 6 interrupted to a high voltage in the secondary coil 1 to induce. The secondary coil 1 conducts the induced high voltage to a spark plug across the port 9 further.

The secondary coil 1 and the primary coil 6 with the primary coil core 8th are with a plastic 32 overmolded, causing the secondary coil 1 and the primary coil 6 are electrically insulated to the outside. Likewise, the secondary coil 1 opposite the cylindrical core 2 electrically isolated. In addition, the gap between the secondary coil 1 and primary coil core 8th with the plastic 32 filled in, leaving the secondary coil 1 opposite the primary coil 6 is electrically isolated. In addition, the cylindrical core can 2 and further components, not shown, of the pencil ignition coil 3 like the electrical contacts, with the plastic 32 to be overmoulded.

2 shows a winding mandrel 20 on which one with at least one coat of varnish 26 coated wire 18 is wound up. The coated wire 18 becomes progressive on the mandrel 20 wound. That is, the wire 18 becomes at an angle α with respect to the longitudinal axis 12 of the winding mandrel 20 (or with respect to the longitudinal axis 13 the secondary coil 1 ) wound up. That is, the wire is wound up in a frusto-conical shape. A leg of the angle α runs along the longitudinal axis 12 of the winding mandrel 20 , The coated wire 18 will thus be along the line 11 in winding planes 17 . 17a . 17b wrapped at an angle α with respect to the longitudinal axis 12 of the angular mandrel 20 run. The angle α is at least 20 , preferably at least 25 degrees. This has the advantage of no corona discharge in the secondary coil 1 if this z. B. is installed in an ignition coil can occur. The voltage difference of adjacent turns is due to the winding at an angle of at least 25 ° below the corona discharge voltage.

In 2 is a heating device 14 to recognize. During winding, it is covered with a varnish layer 26 coated wire 18 with the heater 14 heated. It will both the already wound wire 18 , the so-called winding package, as well as the supplied wire 18 heated. This dissolves the outer lacquer layer 26 of the coated wire 18 at least partially. Alternatively, a device can output a solvent, whereby the outer lacquer layer 26 of the coated wire 18 at least partially dissolves. The outer lacquer layer 26 may be a baked enamel layer. The paint layer 26 becomes tacky by dissolving, causing the adjacent turns of the coated wire 18 are glued together during winding. This has the advantage that the wire can not slip and thus can not come to a winding collapse during winding. In 2 are the bonds 19 the adjacent turns of the wire 18 to recognize, by dissolving and bonding the lacquer layer 26 have arisen.

At the dissolve the baked enamel layer is preferably not completely dissolved before a curing he follows.

In 3 is a cross section of at least one lacquer layer 26 coated wire 18 shown. The wire 18 may consist of copper and / or aluminum and / or brass and / or silver and / or nickel. The wire 18 is with a ground paint layer 24 coated. On this ground paint layer 24 is another layer of paint 26 applied. The outer lacquer layer 26 can consist of baked enamel. The baked enamel can dissolve between a temperature of 140 and 300 degrees and thereby become stickable.

In 4 is a feeder 28 represented, the coated with at least one paint layer wire 18 supplies. This coated wire 18 is on the winding mandrel 20 wound. This happens because the mandrel 20 around its longitudinal axis 12 rotated in direction of rotation A. Alternatively, the coated wire can also be used 18 around the non-rotating mandrel 20 be rotated or wound ge. In the following, the term "winding" is intended to include both possibilities.

During winding, the heater blows 14 , which is preferably an air blower, the coated wire with heat, wherein the outer lacquer layer 26 of the coated wire 18 at least partially dissolves and thereby becomes stickable. The adjacent turns of the coated wire 18 are thus glued together. Instead of a heater 14 Also, a device can be used that contains a solvent while winding on the wire 18 outputs. This solvent can also cause the outer lacquer layer of the wire 18 at least partially dissolves and becomes stickable. After the individual turns have been glued together, the at least partially dissolved paint cures again.

After the secondary coil 1 has been wound, the winding mandrel 20 be removed. In 5 is a partial view of a cut secondary coil 1 without winding mandrel 20 and a primary coil concentrically disposed thereabout 6 with a primary coil core 8th shown. Inside the Se kundärspule 1 is a cylindrical core 2 arranged. The partial view is both on the in 5 shown left and cut off on the right side. Because the turns of the secondary coil 1 Stick together, the turns of the secondary coil 1 no longer slip. The secondary coil 1 is self-supporting and therefore forms a solid unit.

The cylindrical core 2 , the wound secondary coil 1 and the concentrically arranged around this primary coil 6 with primary coil core 8th comes with a plastic 32 molded. In addition, other not shown components of an ignition coil 3 , such as the electrical contacts, with the plastic 32 to be overmoulded. This has the advantage that the secondary coil 1 , the primary coil 6 with primary coil core 8th and other components, such as the electrical contacts, are electrically insulated toward the outside. Plastic 32 also forms a sufficient insulation of the secondary coil 1 opposite the core 2 the ignition coil 3 and / or to the primary coil 6 the ignition coil 3 , In this way, the usual Harzverguss the secondary coil 1 avoided in ignition coils according to the prior art, in which also usually a coil core is poured with. The overmolding with plastic is a very simple, time-saving and cost-effective method. In the prior art known hitherto, there is often the problem that it is necessary to slip off a turn of the wire 18 comes, being a turn of the wire 18 with a certain potential of a turn of a wire 18 with a much higher potential, causing a corona discharge or electrical breakdown.

moreover It can in the prior art at a different thermal expansion from bobbin and coil come to cracking. In the present invention This problem occurs less.

The higher the angle α is, under which the wire 18 is wound, the smaller the number of turns of the wire 18 per single winding plane 17 . 17a . 17b , Thus, the electrical voltage difference between two adjacent wires 18 of two successive winding plane 17a . 17b lower. The lower the voltage difference between two adjacent wires 18 of two successive winding plane 17a . 17b is, the less often arises coronary discharge. At an angle of at least 20 degrees with respect to the longitudinal axis 13 the secondary coil 1 there is no coronary discharge.

Claims (17)

Method for producing a secondary coil ( 1 ) for ignition coils by - winding one with at least one lacquer layer ( 26 ) coated wire ( 18 ) on a longitudinal axis ( 12 ) having winding mandrel ( 20 ) at an angle of at least 20 ° with respect to the longitudinal axis ( 12 ) of the winding mandrel ( 20 ), - bonding of adjacent turns of the wire ( 18 ) by dissolving and curing the at least one lacquer layer ( 26 ). A method according to claim 1, characterized in that the at least one lacquer layer ( 26 ) coated wire ( 18 ) at an angle of at least 25 ° with respect to the longitudinal axis ( 12 ) of the winding mandrel ( 20 ) on the mandrel ( 20 ) is wound. A method according to claim 1 or 2, characterized in that the dissolution of the lacquer layer ( 26 ) by heating the lacquer layer ( 26 ) by means of a heating device ( 14 ) is triggered. Method according to one of claims 1 to 3, characterized in that the dissolution of the lacquer layer ( 26 ) is triggered by applying a solvent to the lacquer layer. Method according to one of claims 1 to 4, characterized in that the bonding of the adjacent turns of the wire ( 18 ) during winding. Method according to one of claims 1 to 5, characterized in that as at least one lacquer layer ( 26 ) a baked enamel layer is used. Method according to one of claims 1 to 6, characterized in that the winding mandrel ( 20 ) after being wound from the secondary coil ( 1 ) Will get removed. Method according to claim 7, characterized in that the secondary coil ( 1 ) after removal of the winding mandrel ( 20 ) with plastic ( 32 ) is overmoulded. Secondary coil ( 1 ) for ignition coils, with - a longitudinal axis ( 13 ), - concentric about the longitudinal axis ( 13 ) wound wire ( 18 ), characterized in that the wound wire ( 18 ) at an angle of at least 20 ° with respect to the longitudinal axis ( 13 ), wherein the wire ( 18 ) at least one at least partially dissolvable during winding paint layer ( 26 ) having. Secondary coil ( 1 ) according to claim 9, characterized in that the wound wire ( 18 ) at an angle of at least 25 ° with respect to the longitudinal axis ( 13 ) is wound up. Secondary coil ( 1 ) according to claim 9 or 10, characterized in that the lacquer layer ( 26 ) is a baked enamel layer. Secondary coil ( 1 ) according to one of claims 9 to 11, characterized in that the baked enamel layer consists of polyvinyl butyral or polyamide. Secondary coil ( 1 ) according to any one of claims 9 to 12, characterized in that the dissolved lacquer layer ( 26 ) is adhesive. Secondary coil ( 1 ) according to one of claims 9 to 13, characterized in that a heating device ( 14 ) dissolves the paint layer. Secondary coil ( 1 ) according to any one of claims 9 to 14, characterized in that a device a solvent on the with a paint layer ( 26 ) coated wire ( 18 ), the paint layer ( 26 ). Secondary coil ( 1 ) according to one of claims 9 to 15, characterized in that the secondary coil ( 1 ) has no secondary coil core. Secondary coil ( 1 ) according to claim 16, characterized in that the secondary coil ( 1 ) without secondary coil core with plastic ( 32 ) is coatable.