JPH0120794Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(a) Industrial Application Field The present invention relates to a microwave oven in which a rectangular waveguide that guides microwaves from a microwave oscillation means into a microwave heating chamber is connected to a side wall power supply port of the heating chamber. (B) Prior Art In general, in a microwave oven, it is very important to heat food evenly and uniformly. Conventionally, various measures have been taken to solve this problem, such as installing a stirrer that stirs microwaves in the heating chamber, a turntable that rotates the food on which it is placed, or heating as seen in Japanese Utility Model Publication No. 52-21633. A magnetron antenna is placed on the side wall of the room, and a metal microwave reflecting tongue is placed under the antenna. FIGS. 3 and 4 show a conventional modification of the latter, in which a rectangular waveguide 3 that guides a 2450MHz microwave from a magnetron 2 into a microwave heating chamber 1,
It is connected to the side wall power supply port 4 of the heating chamber 1,
A metal tongue piece 5 is arranged at the lower side of the power supply port so as to protrude into the heating chamber 1. The power supply port 4 and the waveguide 3 each have a width W of 90 mm.
mm, and the height H is 30 mm. Further, the tongue piece 5 has a pentagonal shape as shown in the figure, and the dimensions a and b are each 10
mm, 35mm. Note that the width of the tongue piece 5 is 90 mm, similar to the power feeding port 4 and the waveguide 3. Therefore, when testing uneven heating of food using such a microwave oven, it has never been possible to sufficiently eliminate uneven heating. That is, five beakers 6, 6, . . . containing 240 c.c. of water (water temperature: 20° C.) are arranged on the bottom surface 1a of the heating chamber 1 as shown in FIG. 5, and microwave heated for 2 minutes. After heating, the water temperature in each beaker 6, 6... is measured. In this case, the water temperature in each beaker 6, 6... is different. It should be noted that if the water temperatures are all the same, there will be no uneven heating, which is most preferable. Next, the water temperature before heating (20° C.) is subtracted from each of the measured water temperatures to obtain the water temperature increase value of each beaker 6, 6, . . . . Then, the deviation rate P is determined from the following equation. P = (maximum water temperature increase value) - (minimum water temperature increase value) / (5
The average value of the two water temperature rise values) Here, the deviation rate P in the above microwave oven is 27
%. The larger the deviation rate P, the more severe the heating unevenness, and the smaller the value, the less uneven heating. In this case, the above deviation rate P of 27% means that heating unevenness has not been sufficiently eliminated. (c) Problems that the invention attempts to solve It would be good to have a microwave oven that can further eliminate uneven heating. (d) Means for solving the problem In a microwave oven in which a rectangular waveguide that guides microwaves from a microwave generating means into a microwave heating chamber is connected to a power supply port on the side wall of the heating chamber, the power supply port is A metal tongue piece is arranged near the lower side so as to protrude into the heating chamber, and a metal partition plate that divides the power supply port into an upper and lower part is arranged at the power supply port so as to project into the heating chamber. do. (e) Effect The simple structure can sufficiently eliminate heating unevenness since the propagation state of microwaves is complicated. (F) Example A microwave oven according to an example of the present invention will be described below. Note that the same parts as in the conventional example are denoted by the same reference numerals, and their explanations will be omitted. In FIGS. 1 and 2, the side wall power supply port 4
A metal partition plate 7 that divides the heating chamber into upper and lower halves is arranged at the power supply port 4 so as to protrude into the heating chamber 1. The partition plate 7 is parallel to the tongue piece 5 and has a T-shape, and a portion 7 a of the partition plate 7 is located inside the waveguide 3 . The distance h of the partition plate 7 from the tongue piece 5 is 20 mm, and the dimensions a' to f' of the partition plate 7 are 25, 65, 40, 5, 20, and 20 mm, respectively.
It is. When the same experiment as the conventional one was carried out by appropriately changing the protrusion dimension X of the partition plate 7, the protrusion dimension X was found to be
The deviation rate P for each value is as shown in the following table.

[Table] Here, as described above, the tongue piece 5 is arranged at the lower side of the power supply port 4, and the power supply port 4 is arranged so that the partition plate 7 that divides the power supply port 4 into two vertically protrudes into the heating chamber 1.
By arranging the tongue piece 5, the deviation rate is significantly smaller than the deviation rate of 27% in the conventional structure (only the tongue piece 5 is placed), and it can be seen that heating unevenness is significantly eliminated compared to the conventional structure. Ru. This is because the partition plate 7 that divides the power feed port 4 into two vertically is arranged in the power feed port 4 so as to protrude into the heating chamber 1, which makes the state of microwave propagation into the heating chamber 1 more complicated than before. It is thought that this is because he has grown old. Note that the magnetron 2 is attached to the lower side of the waveguide 3, and in this case, the antenna 2a is located approximately at the center of the width W of the waveguide 3. In the waveguide 3 to which the magnetron 2 is attached in this way, the E-plane (wall surface parallel to the electric field) of the waveguide 3 is on both sides, and the H-plane (wall surface parallel to the magnetic field) is on the upper side. ,
This is the lower wall. Further, in the above embodiment, the partition plate has a T-shape, but it goes without saying that the partition plate is not limited to such a shape. (g) Effects of the invention According to the invention, a metal tongue piece is arranged near the bottom of the side wall power supply port to which the rectangular waveguide is connected so as to protrude into the heating chamber, and the power supply port is divided into upper and lower parts. Since the metal partition plate is disposed at the power supply port so as to protrude into the heating chamber, uneven heating can be significantly eliminated with a simple structure, and a microwave oven that performs uniform microwave heating can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the main parts of a microwave oven according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the line - - in Fig. 1, Fig. 3 is a sectional view of a conventional microwave oven, and Fig. 4 is a perspective view of the main parts. , FIG. 5 is a plan view of the main part for explaining the experimental state of the same range. 1... Microwave heating chamber, 2... Magnetron, 3... Rectangular waveguide, 4... Side wall power feed port, 5...
...Metal tongue piece, 7...Metal partition plate.

Claims (1)

[Scope of utility model registration request] In a microwave oven in which a rectangular waveguide that guides microwaves from a microwave generating means into a microwave heating chamber is connected to a power supply port on a side wall of the heating chamber, a metal tube is installed near the lower side of the power supply port so as to protrude into the heating chamber. A microwave oven characterized in that a metal tongue piece is disposed and a metal partition plate that divides the power supply port into upper and lower parts is arranged at the power supply port so as to protrude into the heating chamber.