KR19990056502A - Microwave Oven Improves Cooling Performance of Microwave Oscillation Tubes - Google Patents

Abstract

The present invention relates to a microwave oven having an ultra-high frequency oscillation tube, the microwave oven of the microwave oven of the present invention, while maintaining the interior of the vacuum means 120, the cathode 132, the first grid 134, Surrounds the bottom of the second grid 142, the choke structure 136 and the anode 146, the bottom wall 106 of which passes through the sidewalls to guide cooling air from the cooling fan 238. A lower case 105 having a lower guide portion 106a protruding toward the 238 side; It surrounds the upper portion of the anode 146 and the cooling fins 148, the other end of the antenna 150 protrudes upwards through the upper wall 103 and the upper wall 103 is the cooling fan 238 And an upper case (102) having an upper guide portion (103a) protruding toward the cooling fan (238) through its sidewalls to guide cooling air from therefrom.

According to the present invention, unlike a microwave oven to which a conventional magnetron is applied, a high-pressure transformer is unnecessary, so that a small cooling fan can be used, thereby achieving low cost and light weight of the product, and a guide for guiding cooling air from the cooling fan. The part is provided to improve the cooling performance of the ultra-high frequency oscillation tube.

Description

Microwave Oven Improves Cooling Performance of Microwave Oscillation Tubes

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oven, and more particularly, to a microwave oven capable of using a small cooling fan, achieving low cost and light weight of a product, and improving performance of cooling an ultra high frequency oscillation tube.

As shown in Fig. 1, for example, a magnetron 10 driven at a high voltage of 4 kV is employed as an ultra-high frequency oscillation tube in a conventional microwave oven. Since the magnetron 10 operates at a high pressure, a high voltage transformer 2 for boosting a commercial power supply is required. The high voltage transformer 2 generates heat at a constant temperature due to its characteristics and structure. The heat generated in the high voltage transformer 2 and the heat generated during the operation of the magnetron 10 increases the temperature of the microwave circuit component space, The risk of causing malfunctions is increased. Therefore, in order to prevent such a temperature rise, a cooling fan 38 is installed as shown in FIG. 2 to cool the magnetron 10 and the high voltage transformer 2. However, in order to simultaneously cool the magnetron 10 and the high-pressure transformer 2, a large cooling fan 38 is required, and a motor (not shown) for driving the large cooling fan 38 is also required. As a result, the price and weight of microwave ovens are increasing.

Accordingly, the present invention has been made in accordance with the present invention, it is possible to operate without a high-voltage transformer to reduce the size of the cooling fan, to provide a microwave oven that can achieve a lighter weight and lower cost of the product.

As a means for achieving the above object, the microwave oven of the microwave oven of the present invention comprises a heating means; A cathode disposed above the heat generating means and emitting hot electrons by heating the heat generating means; A grid disposed on top of the cathode for focusing hot electrons emitted from the cathode in accordance with the formed bias voltage; A choke structure disposed between the cathode and the first grid to form an input cavity therewith, the choke structure for passing a surface current induced in the first grid and blocking a direct current applied to the cathode; A second grid disposed on the first grid to allow hot electrons to pass through the first grid; An anode disposed on top of the second grid to form an output cavity with the second grid; A plurality of cooling fins arranged outside the anode to radiate heat of the anode; An antenna, one end of which is installed in the anode and which propagates microwaves generated in the output cavity to a cooking chamber; Surrounds the lower portion of the heat generating means, the cathode, the first grid, the second grid, the choke structure and the anode so as to maintain the interior thereof in a vacuum so that the bottom wall guides the cooling air from the cooling fan. A lower case having a lower guide part protruding to the cooling fan side through a side wall; It surrounds the upper part of the anode and the cooling fins, the other end of the antenna protrudes upwards through the upper wall and the upper wall protrudes through the side wall to the cooling fan side to guide cooling air from the cooling fan. It characterized in that it comprises an upper case having an upper guide portion.

According to the present invention, since a high-pressure transformer is unnecessary, a compact cooling fan can be used to achieve low cost and light weight of the product, and a guide part for guiding cooling air from the cooling fan can provide cooling performance of the ultra high frequency oscillation tube. Improve.

1 is a schematic front sectional view of a microwave oven employing a magnetron as an ultra-high frequency oscillation tube,

FIG. 2 is a schematic side cross-sectional view of the microwave oven shown in FIG. 1;

3 is a cross-sectional view showing the structure of a microwave oven for microwave oven according to an embodiment of the present invention,

4 is an enlarged detail view of the main portion of FIG. 3;

5 is a perspective view illustrating the cathode of FIG. 4;

FIG. 6 is a perspective view illustrating the first and second grids of FIG. 4;

FIG. 7 is a schematic front sectional view of the microwave oven employing the ultra-high frequency oscillation tube of FIG.

8 is a schematic side cross-sectional view of the microwave oven of FIG. 7.

<Description of the symbols for the main parts of the drawings>

100: high frequency oscillation tube 102: upper case

103a, 106a: upper and lower guide parts

105: lower case 110: power input unit

120: heater 130: input cavity

132: cathode 134: first grid

136: choke structure 140: output cavity

142: second grid 144: projection

146: anode 148: cooling fin

150 antenna 152 coupling end

154: antenna ceramic 156: antenna cap

160: feedback rod 170: slot-shaped rectangular opening

172: ceramic fin 238: cooling fan

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

Microwave oscillation tube for microwave oven according to a preferred embodiment of the present invention, as shown in Figure 3, the power input unit 110, the heater 120 as a heating means, the cathode 132, and the first and first And two grids 134 and 142, an anode 146, and a feedback rod 160. The lower case 105 connects the power input unit 110, the heater 120, the cathode 132, the first and second grids 134 and 142, the lower part of the anode 146, and the feedback rod 160. The upper case 102 surrounds the plurality of cooling fins 148 arranged on the top of the anode 146 and on the outside of the anode. Meanwhile, one end of the antenna 150 for propagating the generated microwaves to the cooking chamber is positioned in the anode 146, and the other end thereof protrudes upward through the upper wall 103 of the upper case 102. The inside of the lower case 105 and the antenna 150 portion of the anode 146 maintain a vacuum. The upper wall 103 of the upper case 102 and the bottom wall 106 of the lower case 105 each have upper and lower guide portions 103a and 106a that protrude radially outwards through the sidewalls. As illustrated in FIG. 8, the guide portions 103a and 106a extend toward the cooling fan 238 to guide cooling air from the cooling fan 238.

In the ultra-high frequency oscillation tube 100 of the present invention, the cathode 132, which is an electron radiator, emits hot electrons by an indirect heating method by the heat generation of the heater 120 composed of an annular filament as a heat generating means. That is, as shown in FIG. 4, when the cathode 132 disposed on the top surface of the heater 120 is heated to about 600-1200 ° C. by the heat of the heater 120, the electrons are emitted.

The input cavity 130 is a space surrounded by the cathode 132, the first grid 134, and the choke structure 136, and the cathode 132 has a ring shape with a hole formed in the center thereof, as shown in FIG. 6. The first grid 134, which is arranged at a predetermined interval on top of the cathode 132, is applied to a bias voltage to control and focus electrons emitted from the cathode 132 to the input cavity 130. At this time, the first grid 134 and the cathode 132 is electrically insulated, that is, the direct current must be shielded, the surface current forming the microwave inside the input cavity 130 must be energized, so choke for this purpose The structure 136 is arranged between the cathode 132 and the first grid 134.

The output cavity 140 arranged on the upper portion of the input cavity 130 is installed to face the upper portion of the first grid 134 of the input cavity 130 so that surface current is increased while electrons passing through the first grid 134 pass. A space surrounded by the induced second grid 142 and the anode 146 having protrusions 144 protruding downward from the bottom surface, in which the electrons focused on the input cavity 130 are densely modulated and thus, the first grid. Accelerated by the potential difference between 134 and the second grid 142, the microwave is formed by the surface current induced in the second grid 142. The anode 146 that dissipates the slowed-down electron beam is also stacked with a plurality of cooling fins 148 to radiate heat.

As shown in FIG. 6, the first and second grids 134 and 142 are identical to each other in a shape corresponding to the cathode 132 as a metal material, and have a slot-shaped quadrangular shape along a circumferential direction around an inner hole. An opening 170 is formed, and a predetermined gap is maintained by the ceramic pin 172 (FIG. 3) provided between the choke structure 136 and the output cavity 140.

The electrons focused on the input cavity 130 are densely modulated by the automatic shielding function of the bias power of the first grid 134 to pass through the first grid 134, and at this time, the input / output cavities 130 and 140 insulated from each other. When the operating voltage is applied, the potential difference is generated therebetween, and electrons passing through the first grid 134 are accelerated to pass through the second grid 142, so that surface current is generated in the output cavity 140. Induced. As a result, microwaves are formed in the output cavity 140, and the formed microwaves penetrate through the center of the anode 146 and are radiated through the antenna 150 formed in the output cavity 140. For this purpose, the coupling end 152 of the antenna 150 is located in the output cavity 140. The antenna ceramic 154 and the antenna cap 156 connected to the upper portion of the antenna 150 have the same structure as a conventional magnetron.

On the other hand, the ultra-high frequency oscillation tube 100 of the present invention, the feedback rod 160 for feeding back a portion of the microwave formed in the output cavity 140 in the center between the input and output cavity (130, 140) to the input cavity 140 This is installed to amplify and resonate microwave power.

According to the present invention, since a conventional high pressure transformer is unnecessary, a compact cooling fan can be used to achieve low cost and light weight of the product, and a guide portion for guiding cooling air from the cooling fan is provided to cool the ultra high frequency oscillation tube. Improve performance

Claims (1)

In a microwave oven having an ultra-high frequency oscillation tube, The ultra-high frequency oscillation tube and the heating means; A cathode disposed above the heat generating means and emitting hot electrons by heating the heat generating means; A grid disposed on top of the cathode for focusing hot electrons emitted from the cathode in accordance with the formed bias voltage; A choke structure disposed between the cathode and the first grid to form an input cavity therewith, the choke structure for passing a surface current induced in the first grid and blocking a direct current applied to the cathode; A second grid disposed on the first grid to allow hot electrons to pass through the first grid; An anode disposed on top of the second grid to form an output cavity with the second grid; A plurality of cooling fins arranged outside the anode to radiate heat of the anode; An antenna, one end of which is installed in the anode and which propagates microwaves generated in the output cavity to a cooking chamber; Surrounds the lower portion of the heat generating means, the cathode, the first grid, the second grid, the choke structure and the anode so as to maintain the interior thereof in a vacuum so that the bottom wall guides the cooling air from the cooling fan. A lower case having a lower guide part protruding to the cooling fan side through a side wall; It surrounds the upper part of the anode and the cooling fins, the other end of the antenna protrudes upwards through the upper wall and the upper wall protrudes through the side wall to the cooling fan side to guide cooling air from the cooling fan. Microwave oven comprising an upper case having an upper guide portion.