Electromagnetic device, high-voltage generating device, and method for making the electromagnetic device

Abstract

An electromagnetic device and a high-voltage generating device which are thin and improved in the characteristics are provided in which a magnetic core 3 is made of a cylindrical form of a ferrite material having a higher intrinsic resistance. A winding is provided by winding a flat rectangular wire conductor 2 in an edge-wise winding form directly on substantially the entire length of the magnetic core 3. As any insulator such as a coil bobbin is not needed between the flat rectangular wire conductor 2 and the magnetic core 3, the winding can be decreased in the overall size or thickness thus contributing to the dimensional reduction of the electromagnetic device. Also, as its flat rectangular wire conductor 2 is wound directly on the magnetic core 3, the winding can be minimized in the length and thus the overall resistance. Moreover, as there is no gap between the winding and the magnetic core 3, the self-inductance can be reduced while the size and the number of turns of the winding remain unchanged.

Description

[0001] This application is a continuation of Application Ser. No. 09 / 129,105, filed Jul. 7, 2002, the contents of which are expressly incorporated by reference herein in its entireties.FIELD OF THE INVENTION [0002] The present invention relates to an electromagnetic device, a high-voltage generating device, and a method for making the electromagnetic device. BACKGROUND OF THE INVENTION [0003] It is necessary for starting a high intensity discharge lamp such as a high-intensity discharge (HID) lamp to use a high-voltage generating device called an igniter. The high-voltage generating device is generally provided in the form of ant electromagnetic device such as a pulse transformer for converting a low-voltage input to a high-voltage output of pulsed waveform (as disclosed in, for example, Japanese Patent Laid-open Publications 11-16752 and 11-74132). [0004] One of such conventional electromagnetic devices is shown in structure in FIGS. 65 to 68. A coil bobbin 60 is made of an insulat...

AI Technical Summary

Benefits of technology

[0014] In the present invention, an electromagnetic device comprises a magnetic core having a curved side and a flat rectangular wire conductor wound in an edge-wise winding form directly on the curved side of the magnetic core. Accordingly, as any insulator such as a coil bobbin is not needed between the flat rectangular wire conductor and the magnetic core, the winding can be decreased in the overall size or thickness, thus contributing to the dimensional reduction and the improvement of characteristics of the device. In the device, the magnetic core has an intrinsic resistance of not smaller than 1000 Ω.m.

[0015] The electromagnetic device further comprises a winding provided on the outer surface of the flat rectangular wire conductor. Accordingly, a resultant transformer can be reduced in the thickness.

[0016] The magnetic core is rough finished at the surface. Accordingly, as no extra step such as polishing is needed after the completion of the magnetic core, the production cost of the magnetic core can be lowered. Also, the flat rectangular wire conductor can be protected from slipping and tilting down during the edge-wise winding process.

Problems solved by technology

In case of a bobbin-less device, the terminals connected with the coil windings may be secured with much difficulty.

Since the coil windings of a metallic material create undesired events of spring back, their ends have to be bound together or supported by any proper means.

The edge-wise winding may cause the coating of the coil windings to be peeled off when its curvature radius is too small.

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