KR20010037850A - High voltage transformer for microwave oven - Google Patents

Abstract

PURPOSE: A high-pressure transducer for a microwave oven is provided to prevent a reduction of product life due to deterioration by smoothly cooling high-temperature heat and to easily strengthen an insulation characteristic without an additional impregnation process. CONSTITUTION: A high-pressure transducer for the microwave oven includes a core(110), first and second coils(132,134) wound on the core, a pass core(120) inserted between the first and second coils, a synthetic resin(150), and a protective cap(160). The synthetic resin having an excellent thermal conductivity is molded to be coated on a circumference of the first and second coils and the pass core. The protective cap is inserted into a position, where the first and second coils are contacted with the core, to maintain a clearance of insulation.

Description

High voltage transformer for microwave oven

The present invention relates to a high-voltage transformer for a microwave oven, and more particularly, to a high-voltage transformer for a microwave oven, which facilitates heat dissipation from primary and secondary coils and at the same time reinforces insulation characteristics.

In general, a microwave oven is cooked in various ways according to the type of food in a radio wave dispersion method using a high frequency oscillated from a magnetron, Figure 1 schematically shows the internal structure of the microwave oven.

Referring to FIG. 1, the microwave oven includes a cavity 2 for cooking food in the main body 1 and an electric chamber 3 for supplying high frequency and heater heat to the cavity 2. It is composed of separate. The bottom side of the cavity 2 is provided with a tray 4 for placing food and a drive motor 5 for rotating the tray 4 at low speed. In addition, a heating heater 6 is mounted on the cavity 2. On the other hand, inside the electric chamber 3, a magnetron 7 for generating a high frequency and a high voltage transformer 8 for applying a high voltage / high current to the magnetron 7, respectively. And a cooling fan 9 for cooling the heat generated therefrom.

The conventional high pressure transformer used for such a microwave oven is shown in FIG.2 and FIG.3. 3 is a cross-sectional view taken along the line AA of FIG.

2 and 3, the conventional high pressure transformer 8 has a core 10 divided into an E-type core 11 and an I-type core 12, which are coupled to each other. It is stratified. First, the secondary coil 15 and the heater coil 16 are inserted into the lottery structure in the E-shaped core 11, and then a pass core 13 is inserted. Later, after the primary coil 14 is inserted, the I-shaped core 12 is seated on a jig (not shown) and welded with the E-shaped core 11. The bracket 18 is welded to the lower end surface of the I-type core 12 so that the inside of the electric compartment 3 can be fixed. Here, as shown in cross-section in Fig. 3, the insulating paper 17a, 17b, 17c made of a paper film film on each circumferential surface of the conventional primary and secondary coils 14, 15 and the pass core 13 is shown. It wraps and insulates from the core 10 mutually.

In the conventional high voltage transformer 8 configured as described above, when a voltage of AC 100 to 220 V is applied through the input terminal 14a of the primary coil 14, the secondary coil 15 has a voltage of approximately AC 2500 V. High voltage is induced and supplied to the magnetron 7.

However, the work of wrapping the insulating paper 17a, 17b, 17c around each of the primary and secondary coils 14, 15 and the pass cores 13 is not very demanding, so there is a high risk of dielectric breakdown. Be careful. Therefore, the assembly workability and productivity of the product has a problem.

In addition, since the insulating paper 17a, 17b, and 17c has a property of blocking heat transfer, high heat generated from the primary and secondary coils 14 and 15 when the high voltage is induced is transferred to the core 10 and cooled. This will greatly increase the possibility of product deterioration. This will reduce the reliability of the trans product because it will shorten the life of the trans product.

Furthermore, in order to reinforce the insulating properties, a varnish impregnation process, that is, an entire process of immersing the assembled high-pressure transformer 8 in a container containing a predetermined solution, followed by drying and cooling for a certain period of time, results in the entire production process. It acts as a delaying factor.

Therefore, the present invention was created to solve the above-mentioned problems, an object of the present invention by using a resin injection molding method to smoothly cool the high heat emitted from the primary and secondary coils by deterioration products It is to provide a high-pressure transformer for a microwave oven that can prevent the shortening of the service life of.

Another object of the present invention is to provide a high-voltage transformer for a microwave oven which can reinforce insulation properties very easily without using a method of wrapping an insulating paper between the primary and secondary coils and the core or adding a separate impregnation process.

1 is a cross-sectional view schematically showing the internal structure of a typical microwave oven.

Figure 2 is a perspective view showing a high-pressure transformer for a conventional microwave oven.

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

Figure 4 is a perspective view of a high pressure transformer for a microwave oven according to the present invention.

5 is a cross-sectional view taken along the line B-B in FIG.

FIG. 6 is a plan view of a portion of FIG. 4;

Explanation of symbols on the main parts of the drawings

100: high pressure transformer, 110: core,

120: pass core, 132: primary coil,

134: secondary coil, 140: heater coil,

150: synthetic resin, 160: protective cap,

162: guide jaw.

In order to achieve the above object, a high-voltage transformer for a microwave oven according to the present invention includes a core in which a plurality of metal flakes are laminated, a primary coil wound on the core, and a secondary coil inserted between the primary coil and the secondary coil. A high-pressure transformer for a microwave oven comprising a pass core, wherein the primary and secondary coils and a synthetic resin having excellent thermal conductivity are molded to be insulated and applied to the circumference of the primary and secondary coils, and The protective cap is further inserted into the contact portion with the core so as to maintain the insulation gap.

It is preferable that the said synthetic resin consists of a bulk molding compound (BMC).

The protective cap is separately covered on the outer circumferential surface of the first and secondary coils, and it is preferable that the guide jaw is further provided to facilitate penetration of the synthetic resin.

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

4 is a perspective view showing a high-pressure transformer for a microwave oven according to the present invention. FIG. 5 is a cross-sectional view taken along the line BB of FIG. 4, and FIG. 6 is a plan view taken along a portion of FIG. 4.

In the figure, reference numeral 100 denotes a high voltage transformer applying high voltage / high current to the magnetron (7 in FIG. 1). The basic configuration of such a high pressure transformer 100 is similar to the conventional. That is, the transformer 100 is provided with a core 110 composed of an E-type core 112 and an I-type core 114 in which a plurality of metal sheets are laminated. In addition, a pass core inserted between the primary and secondary coils 132 and 134 wound on the core 110, that is, the E-shaped core 112, and the primary and secondary coils 132 and 134. 120). Of course, the secondary coil 134 forms a lottery structure with the heater coil 140.

However, in the exemplary embodiment of the present invention, molding is performed so that the synthetic resin 150 having excellent thermal conductivity around the primary and secondary coils 132 and 134 and the pass core 120 can be insulated and coated therein. do. Here, as the resin molded synthetic resin 150, for example, an unsaturated polyester resin, a curing agent, a filler, a coloring agent and the like is formed of a bulk molding compound (Bulk Molding Compound) (BMC) is preferably formed. Since the injection molding machine is used, the insulation and heat dissipation effect can be easily seen without the need of wrapping the insulation paper as before.

In addition, since the protective cap 160 is further inserted into the contact portion between the primary and secondary coils 132 and 134 and the core 110, the present embodiment may easily maintain an insulation gap. In addition, the protective cap 160 is separately coated on the outer circumferential surfaces of the first and second coils 132 and 134, and when the guide jaw 162 is further provided, the synthetic resin (BMC) 150 is provided. It is very preferable that penetration of can be made easily.

Reference numeral 132a denotes an input terminal provided on the primary coil 132 side, and 134a is an output terminal provided on the secondary coil 134 side. Further, reference numeral 170 denotes a bracket for fixing to the electric compartment of the microwave oven.

Looking at the assembly process and operation relationship of the high-pressure transformer 100 according to the present invention provided as described above, first, the secondary coil 134 and the heater coil 140 is inserted into the lottery structure in the E-type core 112, Next, a pass core 120 is inserted. Later, after the primary coil 132 is inserted, the I-type core 114 is seated on a jig (not shown) and welded with the E-type core 112. At this time, the protective cap 160 is overlaid on the outer surfaces of the primary and secondary coils 132 and 134 and then simply inserted into the E-type core 112. Of course, although not shown in Figure 5, it is preferable that the protective cap 160 is also covered on the outer surface side of the pass core 120.

Thereafter, the injection molding machine penetrates and molds the synthetic resin 150 made of bulk molding compound (BMC) from the outer side of the primary and secondary coils 132 and 134 protruding out of the core 110. . Since the synthetic resin 150 functions to easily dissipate (heat) the high heat generated from the coils 132 and 134, the synthetic resin 150 covers the temperature rise. Furthermore, the synthetic resin material 150 can easily penetrate into the empty space inside the core 110 by the guide tuck 162 of the protective cap 160.

Therefore, insulation properties are reinforced without the need for a separate insulation reinforcement work such as a varnish impregnation process as in the related art, and can be easily assembled while maintaining the insulation gap using the protective cap 160.

According to the present invention described above, it is possible to smoothly radiate or cool the high heat emitted from the primary and secondary coils using the resin injection molding method, thereby preventing the shortening of the life due to deterioration, thereby further improving the reliability of the product. Can be.

In addition, by inserting a protective cap between the primary and secondary coils and the core, it is possible to easily reinforce the insulating properties by not inserting a protective cap, and to eliminate the need for additional impregnation process. You can increase it even more.

Claims (3)

A high voltage transformer for a microwave oven comprising a core in which a plurality of metal flakes are laminated, a primary coil wound on the core, and a pass core inserted between the primary coil and the secondary coil, A protective cap is molded to insulate and penetrate the primary and secondary coils and the pass cores with excellent thermal conductivity in an insulating manner, and to maintain an insulation gap on the contact portion with the cores of the primary and secondary coils. A high pressure transformer for a microwave oven, characterized in that the insertion further. The method of claim 1, The synthetic resin is a high-pressure transformer for a microwave oven, characterized in that consisting of a bulk molding compound (BMC). The method of claim 1, The protective cap is respectively covered on the outer circumferential surface of the first and secondary coils, and a high pressure transformer for the microwave oven, characterized in that the guide jaw is further provided to facilitate the penetration of the synthetic resin.