A coil winding and machine

Abstract

 A coil winding machine by which a wire (3) is fed with a constant tension through a nozzle (4) and wound round a bobbin (6) attached to a rotating shaft (5). This machine is featured by the fact that the wire (3) can be tightly coated with insulating resin fed and melted in the nozzle head (4) while it passes the nozzle head (4). This ensures forming tight insulation between series of wire turns of the coil device.

Description

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a coil winding machine for manufacturing coil devices such as engine ignition coils and so on. Conventionally, the insulation of a coil device is achieved by winding an electrically conductive wire previously covered with an enamel coat into a coil unit or by winding uncovered wire into a coil unit, impregnating it in insulation varnish and drying to form an interlayer insulation thereof.

[0002] A conventional engine ignition coil device is manufactured by the following process:

[0003] Primary and secondary coils are formed by winding a wire covered with insulation round corresponding bobbins which are then mounted in a coil case (coil casing) and potted with thermoplastic insulation resin (epoxy resin) poured, as melted, into the case, wherein the first and the second coils are impregnated with insulation resin. The case with coils is integrally molded by solidification of the poured resin therein.

[0004] However, the above-described conventional coil devices involve the following problems to be solved:

[0005] The coil device manufactured by winding the wire with insulating coating requires a separate process of previously covering the wire with an insulation coat.

[0006] The process of impregnating the formed coils with insulating varnish (resin) may cause poor coating of multiple turns of the fine wire with insulating resin, resulting in that the coil device has a decreased performance and may be heated to a high temperature while working.

[0007] In the engine ignition coil device, its secondary coil formed by winding a fine wire of 0.05 mm in diameter in a large number of turns on the secondary bobbin may be scarcely impregnated with insulating varnish (resin).

[0008] In the conventional engine ignition coil device comprising a case with a coil unit potted therein with melted thermoplastic resin, the coil unit cannot be removed from the case once the resin injected in the case with the coil unit was solidified.

SUMMARY OF THE INVENTION

[0009] Accordingly, an object of the present invention is to provide a coil winding machine for winding a non-insulated wire fed with a constant tensioning force from a spool through a nozzle round bobbins mounted on a rotating shaft, wherein the nozzle is filled with melted insulating resin in order to form insulation coating on the wire passing through the nozzle.

[0010] Another object of the present invention is to provide a coil winding machine, wherein a thermoplastic resin is used for forming insulating coating on a wire to ensure the re-use of the wire of the coil device.

[0011] Another object of the present invention is to provide a coil winding machine for manufacturing an engine ignition coil device comprising a case with a coil unit mounted therein and potted with melted insulating resin to form an integrated coil device with solidification of resin in the case, wherein the resin is thermoplastic to ensure separation of the coil unit from the case by re-melting the resin therein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic illustration of a typical construction of a coil winding machine for manufacturing a coil device.

[0013] Figure 2 is a schematic illustration of a nozzle portion of the coil winding machine of Fig. 1, which portion is an embodiment of the invention.

[0014] Figure 3 is a schematic illustration of a nozzle portion that is another embodiment of the present invention.

PREFERRED EMBODIMENT OF THE PRESENT INVENTION

[0015] Fig. 1 is illustrative of a typical construction of coil winder by which a wire 3 being fed from a spool 1 with a specified force through a tensioning device 2 and a nozzle head 4 reciprocating along a longitudinal axis of a rotation shaft 5 is wound spirally in layers of wire turns to form a coil on a rotating coil bobbin 6 coaxially attached to a rotating shaft 5 which is driven by a driver 8 under the control of a controller 7.

[0016] In this coil winder, the present invention is implemented by the nozzle head 4 which, as shown in Fig. 2, is provided at its top with a funnel-shaped hopper 10 for feeding pellets 9 of insulating resin therein and provided at its periphery with a heater 11 wound thereon, a power source 13 of which can be turned on and off by a switching circuit 12 under the control of the controller 7. Thus, the resin pellets fed in the nozzle head 4 are melted by heat to form an insulating coating on the wire 3 passing the nozzle head 4.

[0017] According to the present invention, the wire 3 is tightly covered with insulation resin while passing the nozzle head 4. This process can easily obtain high quality of insulation of the coil device that can have high performance and reliable protection from being heated. This is particularly advantageous for manufacturing a secondary coil consisting of a large number of turns of a fine wire having a diameter of 0.05 mm.

[0018] Figure 3 is illustrative of a horizontal type nozzle head 4' provided with a hopper 10'.

[0019] In both embodiments of the present invention, thermoplastic resin is used as insulating resin to form an insulating coating on the wire 3.

[0020] Therefore, the wire 3 of the coil formed on the bobbin 6 can be restored for re-use by melting the resin coat by heat.

[0021] According to the present invention, an engine ignition coil device can be manufactured with a single case (casing) in which a coil unit consisting of a primary coil-wound bobbin and a secondary coil-wound bobbin having connecting terminals and cores are assembled and potted with melted insulation resin poured and solidified therein. Since the poured and solidified resin in the ignition coil device is thermoplastic, the coil unit can be removed from the coil case by re-melting by heat the mold resin therein, thus the wire, the connecting terminals and the cores can be further separated from one another.

[0022] As is apparent from the foregoing, the coil winding machine according to an embodiment of the present invention can manufacture a coil device by winding a wire fed with a specified tension from a nozzle head round a bobbin attached to a rotation shaft, wherein the nozzle head is preliminarily filled with insulation resin melted by heat to form insulating coating on the wire passing through the nozzle head. The advantage of this process is to easily manufacture a high performance coil device having a high-quality interlayer insulation between wire turns of the coil device and having a restricted temperature characteristic.

[0023] The coil winding machine according to the present invention can produce a coil device by winding round a bobbin a wire covered with an insulating layer of thermoplastic resin, which wire can be restored for re-use in future by melting the insulating resin.

Claims

1. A coil winding machine for winding a wire (3) fed with a constant tension from a spool (1) through a nozzle portion (4) round at least one bobbin (6) attached to a rotation shaft (5), wherein the nozzle portion (4) is filled with melted insulating resin to form an insulating coating on the wire (3) passing through the nozzle portion (4).

2. A coil winding machine as defined in claim 1, wherein the nozzle portion (4) is provided with a feeder (10) for supplying insulation resin pellets (9) into the nozzle portion (4) and is also provided at its outside with a heater (11) for heating the nozzle portion (4) to melt the resin pellets therein.

3. A coil winding machine as defined in claim 1 or 2, wherein the insulating resin is thermoplastic resin.

Drawing