JPH0134867Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(a) Industrial application field The present invention relates to a microwave oven. (b) Prior Art Various measures have been taken or proposed to reduce uneven heating in microwave ovens. Conventionally, among these methods, a method is known that takes into account the state of microwave power supply to the heating chamber, as seen in Japanese Patent Publication No. 47-30657, but as in the above-mentioned prior art, a method is known in which a plurality of power supply openings are provided. The structure was not necessarily simple, as each of them was equipped with a variable phase shifter. (c) Purpose of the invention The present invention provides a simple configuration for a microwave oven that reduces uneven heating by considering the microwave power supply state to the heating chamber. (d) Structure of the invention The microwave oven of the invention includes a heating chamber, a microwave generator, and a waveguide means for guiding microwaves output from the generator to the heating chamber, and the waveguide means: Two rectangular waveguides are placed side by side on the outer surface of the heating chamber wall with a part of their side surfaces overlapping, an opening is provided in the overlapping side surface of the waveguide, and the waveguide is arranged to cross the overlapping part. It is characterized in that a power feeding port is formed that communicates each of the waveguides with the wall of the heating chamber. (E) Embodiment Figures 1 to 3 show the microwave oven of this embodiment, where 1 is a heating chamber, 2 is a turntable placed in the heating chamber and rotates on which food is placed, and 3 is a microwave consisting of a magnetron. The generator 4 is a waveguide means for guiding the microwave output from the generator to the heating chamber 1. Below, to explain the waveguide means 4, 5 and 6 are as follows:
First and second rectangular waveguides 7 attached to the heating chamber upper wall 1a are antennas of the microwave generator 3, which are included near the starting end of the first waveguide 5. The first and second waveguides 5 and 6 are located at 1 of their side surfaces 5a and 6a.
The overlapping parts are arranged side by side, and an opening 8 is provided on the side surface of the overlapping part, and the first and second waveguides 5 and 6 are heated in an arrangement that crosses the overlapping part, as shown by the hatched area in the figure. A power supply port 9 communicating with the room upper wall 1a is formed. Therefore, the microwave emitted from the antenna 7 travels inside the first waveguide 5 and passes through the aperture 8 and the feed port 9.
Due to the coupling effect of
Because the power feed port 9 does not extend in a straight line when viewed from the antenna 7, a more complicated pattern of microwaves is supplied from the power feed port 9 into the heating chamber 1, thereby improving uneven heating. . The table below shows the improvement effect on uneven heating achieved by the present invention. In the table, the form A is as shown in Fig. 4A, with the dimensions of the first and second waveguides 5 and 6 determined as shown in the table, and the form B is as shown in Fig. 4B. As shown,
_C
As shown in FIG. 4C, the shape of _FIG . , it means one that is composed of only the first waveguide 5 and has a power feeding port 11 at its terminal end, and each dimension is determined as shown in the table. In addition, in the table, the three-piece method refers to three beakers P _{1 to 3} each containing equal amounts of water on one diameter of the turntable 2, as shown in FIG. 5A.
P ₃ and measure the difference ΔT ₁ to ΔT ₃ between the water temperature in each beaker after heating for a predetermined time and the initial water temperature before heating,
This is a method of calculating the degree of heating unevenness based on the following formula. ΔMax−ΔMin/(ΔT ₁ +ΔT ₂ +ΔT ₃ )/3×100 (However, ΔMax and ΔMin represent the maximum and minimum among ΔT ₁ to ΔT ₃ , respectively.) Furthermore, the 5-piece method is As shown in Figure 5B, three water beakers P ₁ to _{P 5} are placed on each of the two diameters arranged at 90 degrees, and the degree of uneven heating is similarly calculated based on the following formula. be. ΔMax−ΔMin/(ΔT ₁ +ΔT ₂ +ΔT ₃ +ΔT ₄ +ΔT ₅ )/
5 ×100

[Table] From the above table, it is clear that heating unevenness is improved in the case of the present invention. In addition to the above embodiments, the number of waveguides arranged in parallel may be three or more, and the width l ₂ of the first and second waveguides 5, 6 may be
It is also possible to make both l ₃ equal. (F) Effects of the invention According to the invention, heating unevenness can be reduced with a simple configuration that only requires consideration of the arrangement of the waveguide and the feed port.

[Brief explanation of the drawing]

Figures 1 to 3 show the microwave oven of this embodiment, Figure 1 is a side view, Figure 2 is a plan view, Figure 3 is a cross-sectional view of Figure 1, and Figure 4 is a plan view of main parts. , FIG. 5 is a plan view showing the measurement method. 1...Heating chamber, 3...Microwave generator, 4...
...Waveguide means, 5, 6...First and second waveguides, 8...
...Opening, 9...Power supply port.

Claims (1)

[Scope of utility model registration request] A heating chamber, a microwave generator, and a waveguide means for guiding the microwave output from the generator to the heating chamber, and the waveguide means includes at least two rectangular guides on the outer surface of the heating chamber wall. Wave tubes are arranged side by side with parts of their side surfaces overlapping each other, openings are provided in the overlapping side surfaces of the waveguides, and each of the waveguides is communicated with the heating chamber wall by traversing the overlapping portion. A microwave oven characterized by having a power feeding port formed therein.