JPH11111537A - Compact high-voltage transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure insulation between a low-voltage winding and a high-voltage winding with simplified manufacturing operation and a simple structure, by fitting a thin endless rubber-like body with high withstanding voltage and stretchability between the low-voltage winding and the high-voltage winding which are concentrically wound around a winding shaft of a drum-shaped bobbin. SOLUTION: A low-voltage winding 4 is wound around a winding shaft 3 of a drum-shaped core or bobbin 1 integrally formed with the upper and the lower flanges 2a and 2b and the winding shaft 3, and a thin endless rubber-like body 5 with high withstand voltage and stretchability is fitted into the periphery of the low-voltage winding by using the stretchability. A high-voltage winding 6 is concentrically wound around the periphery of the low-voltage winding 4 as putting the endless rubber-like body 5 between the windings. Width W2 of the rubber-like body 5 is equal to or slightly greater than a winding width W1 of the drum-shaped core car bobbin 1. The rubber-like body 5 is made of silicon gum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small high-voltage transformer used for a backlight lighting circuit of a liquid crystal display device and the like, in which insulation between a low-voltage winding and a high-voltage winding is improved.

[0002]

2. Description of the Related Art Conventionally, a voltage of about 1000 V to 2000 V is applied to a high voltage winding of a high voltage transformer used for a backlight lighting circuit of a liquid crystal display device when a discharge lamp is started. In recent years, this type of high-voltage transformer has been downsized,
In order to satisfy this requirement, as shown in FIG. 1, a low-voltage winding 23 and a high-voltage winding 24 are concentrically formed on a winding shaft portion 22 of a bobbin 21 and both windings are formed. Winding is performed so as to be coplanar. In this configuration, an insulating tape 2 is provided between the low-voltage winding 23 and the high-voltage winding 24.
5 or an insulating coating material such as varnish is applied to insulate them.

[0003]

However, in the method of winding the insulating tape, it is necessary to use a thicker one in order to increase the dielectric strength or to increase the number of turns of the insulating tape. A gap 26 is easily formed at both ends in the width direction of the insulating tape, and the high-voltage winding 24 bites into the gap 26, and the low-voltage winding 23 and the high-voltage winding 24 come into contact with each other, which easily causes insulation failure. In particular, the flange 21 of the drum core or drum bobbin 1 around which the low voltage winding and the high voltage winding are wound.
A width (hereinafter, referred to as a winding width) W between a and 21b is, for example, 1
When it is extremely small, such as about 2 mm, there is a disadvantage that the operation of winding the insulating tape requires skill and the working efficiency is poor. Also, in the case of applying an insulating coating material, it is difficult to make the thickness of the coating material layer uniform, so that the degree of coupling between the low-voltage winding and the high-voltage winding is not uniform. There is a disadvantage that the quality of the product varies.

[0004]

SUMMARY OF THE INVENTION According to the present invention, the insulation between a low-voltage winding and a high-voltage winding can be achieved without winding an insulating tape or applying an insulating coating material and by a simple operation. In particular, a drum-type bobbin in which flanges and a winding portion at both ends are integrally formed is suitable for a small high-voltage transformer with a narrow winding width, and is wound concentrically around a winding portion of the drum-type bobbin. A thin endless rubber body having high withstand voltage and elasticity is fitted between the turned low voltage winding and high voltage winding.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on examples. FIG. 2 shows an embodiment of the small high-voltage transformer according to the present invention. In FIG. 1A, reference numeral 1 denotes upper and lower collars 2a and 2a.
a drum-shaped core or drum-shaped bobbin integrally formed with b and the bobbin 3; a low-voltage winding 4 wound around the bobbin 3; and a thin with high withstand voltage and elasticity. The endless rubber body 5 is fitted around the low-voltage winding 4 by utilizing its elasticity. Reference numeral 6 denotes a high-voltage winding wound concentrically around the low-voltage winding 4 via the endless rubber-like body 5. Here, the width W2 of the insulating rubber-like body 5
Is equal to or slightly larger than the winding width W1 of the drum core or drum bobbin 1. An example of the endless rubber body 5 is silicone rubber. The potential difference between the low voltage winding and the high voltage winding wound around the drum core by the inventor is 2
An experiment was conducted in which an endless band (thickness 0.15 mm) molded from silicone rubber (product number: SE1646U) manufactured by Toray Industries, Inc. was fitted around the low-voltage winding of a surface-mount DC / DC converter transformer of 000 V. However, no abnormality was observed, and it was found that the film was sufficiently practical. The characteristic of the silicone rubber band is 5.5 m in diameter.
m, wall thickness: 0.15mm, breakdown voltage: 25kV
/ Mm, heat resistance: 180 ° C, tensile strength: 80kgf /
cm2,

[0006]

As is apparent from the above description, according to the present invention, a low-voltage winding and a high-voltage winding are concentric with a drum core or a drum bobbin in which upper and lower flanges and a winding shaft are integrally formed. In a small high-voltage transformer wound in a spiral shape, a special thin endless rubber body with high withstand voltage and elasticity is simply fitted between the low-voltage winding and the high-voltage winding. Since no labor is required, the manufacturing operation is simple, and there is an effect that the insulation between the low-voltage winding and the high-voltage winding can be reliably performed with a simple configuration.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a conventional small high-voltage transformer, in which (a) is a sectional view and (b) is an enlarged view of a main part.

FIG. 2 is a view showing an embodiment of a small high-voltage transformer according to the present invention;
(A) is sectional drawing, (b) is a perspective view of an endless rubber-like body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Drum core or drum bobbin 2a ... Upper flange 2b ... Lower flange 3 ... Winding shaft 4 ... Low pressure winding 5 ... Endless rubber-like body 6 ... High pressure winding line

Claims (2)

[Claims] 1. A drum core or drum bobbin in which upper and lower flanges and a winding part are integrally formed, a low voltage winding and a high voltage winding, and a low voltage winding and a high voltage winding are mounted on the winding part. In a small high-voltage transformer wound concentrically, a thin, endless rubber body with high withstand voltage and elasticity was fitted between the low-voltage winding and the high-voltage winding. Features a small high-voltage transformer. 2. The small high-voltage transformer according to claim 1, wherein said endless rubber-like body is formed of silicone rubber.