KR100395930B1 - Transformer for micro wave oven - Google Patents

Abstract

The present invention relates to a boost transformer of a microwave oven, by providing a filter layer on a filament winding to absorb electromagnetic waves and absorbing electromagnetic waves from the filter layer, thereby reducing electromagnetic noise generated from the boost transformer and electromagnetic noise from the magnetron. Not only can the pollution be reduced, but the noise attenuation device is provided inside the transformer, so that the assembly process can be shortened.

Description

Booster transformer for microwave oven {Transformer for micro wave oven}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oven, and more particularly, to a boost transformer for a microwave oven capable of attenuating electromagnetic noise.

In general, a microwave oven is a device for cooking by ultra-high frequency unlike an external heating type cooking furniture using heat conduction and heat radiation. The microwave oven generates a high frequency of 2450 MHz by applying a high voltage to a microwave oscillation tube called magnetron. The 2,450MHz high frequency generated from the magnetron changes the direction of the electric field by 2.45 billion times a second. When this high frequency is applied to the food, the molecules that make up the food rotate 2.45 million times a second and a lot of frictional heat. Is generated and food is cooked by this heat.

As described above, in the process of generating the ultra high frequency of 2450 MHz, the magnetron generates electromagnetic noise of about 250 to 300 MHz and about 700 to 800 MHz by high frequency. The high frequency noise is radiated outward through the filament wire and affects an electronic device such as a television or a radio, or is directly conducted from a magnetron to a transformer, thereby affecting its operation.

Accordingly, in order to attenuate electromagnetic noise conducted / radiated from the magnetron through the filament wire, a separate electromagnetic noise attenuator is attached between the magnetron and the transformer.

The conventional electromagnetic noise reduction device has a separate filament coil wound around the ferrite sintered body and has a separate input terminal and an output terminal. The input terminal is connected to the transformer and the output terminal is connected to the magnetron. Noise was absorbed and attenuated.

For this reason, when the magnetron and the transformer are connected in the microwave assembly process, there is a disadvantage in that a process of connecting a separate noise damping device as described above is additionally generated. In addition, as the ferrite is manufactured from a sintered body, the cost increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a boosting transformer for a microwave that attenuates electromagnetic noise generated in a magnetron and reduces manufacturing costs and manufacturing processes.

1 is a circuit diagram of a boost transformer for a microwave oven according to the present invention.

2 is an exploded perspective view of a transformer according to the present invention.

3 is a cross-sectional view taken along the line A-A of FIG.

4A and 4B are explanatory diagrams showing another embodiment according to the present invention.

Explanation of symbols on the main parts of the drawings

11a, 11b, 11c: core 12: 1 primary winding

13: filament winding 13a: filament wire

14: secondary winding 20a, 20b: filter layer

The microwave boosting transformer according to the present invention for achieving the above object is characterized in that it comprises a filter layer on the secondary side to absorb electromagnetic waves.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic circuit diagram of a microwave oven according to the present invention.

Referring to FIG. 1, the primary winding 12 of the boost transformer 10 is connected to an input power source (not shown). One end of the secondary winding 14 of the boost transformer 10 is connected to ground, and a fuse 15 and a high voltage capacitor 16 are connected in series between the other end and the first node node1. In addition, a high voltage diode 17 is connected between the first node node1 and the ground. One end of the filament winding 13 of the boost transformer 10 is connected to the first node node1, and the magnetron 18 is connected between the first node node1 and the other end of the filament winding 13.

The magnetron 18 is a kind of electron tube, and when a filament is heated and a high voltage DC voltage is applied to the anode, the magnetron emits 2450 MHz microwaves by a permanent magnet. The oscillated microwave of 2450 MHz is transmitted from the antenna of the magnetron to the cooking chamber (not shown) through a wave guide.

Figure 2 is an exploded perspective view for explaining a boost transformer for a microwave oven according to the present invention.

3 is a cross-sectional view taken along the line A-A of FIG.

2 and 3, the boosting transformer 10 boosts the input power to a high voltage, and boosts the power applied to the primary winding to a high voltage of about 2100V in the secondary winding. The boost transformer 10 sequentially stores the first core 11a laminated with a thin steel plate, the primary winding 12, the filament winding 13, and the secondary winding 14 in the first core 11a. And a third core 11c covering the upper portion thereof. At this time, a second core 11b is installed between the primary winding 12 and the filament winding 13 to leak a part of the magnetic flux.

The filament winding 13 is a winding of the filament wire 13a three to 3.5 times, the filament winding 13 is formed with a filter layer 20a for absorbing electromagnetic waves. The filter layer 20a is formed by molding the filament winding 13 itself with a resin containing a ferrite component.

4A and 4B are explanatory diagrams showing another embodiment according to the present invention.

4A and 4B, first, the filament wire 13a is molded with a resin containing a ferrite component to form a filter layer 20b (FIG. 4A). The filament wire 13a on which the filter layer 20b is formed is wound 3 to 3.5 times to form the filament winding 13 (b of FIG. 4).

By forming the filter layer 20 on the filament winding 13 as described above, the electromagnetic wave generated in the magnetron 18 and the step-up transformer 10, and generated in the filament winding 13 and the operation of the step-up transformer 10 Electromagnetic waves generated by the filament winding 13 itself are absorbed by the filter layer 40 molded of a resin containing ferrite.

That is, a device for attenuating electromagnetic waves generated by the magnetron 18 is provided in the boosting transformer 10, so that a process of installing a separate electromagnetic wave noise damping device is not required when the microwave oven is assembled.

As described in detail above, according to the microwave boosting transformer according to the present invention, by absorbing electromagnetic waves in the filter layer provided in the filament winding, electromagnetic wave generated from the boosting transformer and electromagnetic noise from the magnetron are reduced to reduce electromagnetic pollution. In addition to this, there is an effect that the noise damping device is provided inside the transformer, thereby shortening the assembly process.

Claims (3)

In a microwave oven having a boost transformer having a primary winding, a secondary winding and a filament winding to boost the input power supply to the magnetron, A step-up transformer for a microwave oven, characterized in that a filter layer is provided on the filament winding to absorb electromagnetic waves. The method of claim 1, The filter layer is a transformer boosting transformer for the microwave, characterized in that formed by molding the entire filament winding made of a resin containing a ferrite wound around the filament wire. The method of claim 1, The filter layer is formed by molding a resin containing a ferrite in the filament wire, the step-up transformer for a microwave oven, characterized in that the filament winding is made by winding a predetermined number of times the filament wire formed with the filter layer.