JPS5830710B2 - High frequency heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention realizes a high-frequency heating device in which fluctuations in load impedance seen from the magnetron are small and the electric field stirring effect within the heating chamber is good.

In a high-frequency heating device, a so-called microwave oven, in which high-frequency waves are supplied through a waveguide and a stirrer fan is provided in the heating chamber, the most typical power supply structure is shown in FIG.

That is, the high frequency waves emitted from the magnetron 1 are irradiated into the heating chamber 4 through the power supply opening 3 via the waveguide 2 .

5 is a metal streak 2-fan that stirs the high frequency,
To improve uneven heating of load 6.

1 shows a dielectric partition plate, 81/'i exterior.

FIG. 2 is a schematic top view of the device showing the positional relationship between the power supply opening 3 and the stirrer fan 5.

According to such a conventional power supply structure, the blades of the stirrer fan 5 intermittently cross the power supply opening 3, and although it is effective in stirring the electric field, that is, improving uneven heating, the magnetron When looking at the load impedance on the heating chamber side using antenna No. 1 as a reference, the change in the load impedance on the heating chamber side is too large. I had no choice but to operate at the operating point.

Therefore, even when the output center is detected, the output level is not very high, and the unstable oscillation region is close (a/ in the figure), so depending on the load amount and load position, abnormal oscillation phenomena such as moding may often occur. Ta.

The present invention focuses on this point and attempts to improve heating unevenness without significantly changing the load impedance.

An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 4 and 5, high frequency waves emitted from a magnetron 1 are introduced into a heating chamber 4 through a power supply opening 3 via a waveguide 2.

The power supply opening 3 is provided approximately in the middle of the upper surface of the heating chamber to ensure symmetry of the electric field in the front, rear, left and right directions within the heating chamber.

Now, the stirrer fan 5 has a stirring blade part 9 made of a conductor,
Orifice occlusion.

It is composed of 10.

The opening closing part 10 is located opposite the power supply opening 3, and is arranged so that the shape seen from the opening 3 remains constant even when the stirrer fan rotates. The outer shape of the opening closing portion 10 is circular, and the outer circumference thereof is larger than the diagonal line of the opening 10.

With this configuration, the change in load impedance seen from the magnetron becomes much smaller than in the conventional case, and therefore the operating point of the magnetron can be kept at a small value of 1 as shown in FIG.

Moreover, since the opening 3 and the stirrer fan opening closing part 10 constantly face each other in parallel, a type of waveguide is equivalently formed in this part, and the high frequency waves are diffused back and forth and left and right as shown by the arrows in the figure, and the magnetron Although the operating point of the blade section 9 is small, the stirring effect of the blade section 9 is significantly improved.

In other words, the high-frequency bus from the magnetron to the heated object 1 is extended, and the stirrer fan rotates at a position far from the magnetron but close to the heated object. It becomes stable and less susceptible to the effects of objects, and the stirring effect of the stirrer fan on the object to be heated is tremendous.

As described above, according to the present invention, it is possible to realize a power supply structure with small changes in load impedance and less uneven heating.
Able to efficiently and stably extract high level output.

Since the distance d from the unstable oscillation region can also be set large while keeping the center of the output, abnormal oscillations such as moding are less likely to occur.

Therefore, it also has the effect of extending the life of the magnetron.

[Brief explanation of drawings]

Figure 1 is a sectional view of the device showing a conventional example, Figure 2 is a top view of the same,
Figure 3 is a Rieke diagram showing the impedance of the heating chamber.
FIG. 4 is a sectional view of a high-frequency heating device showing an embodiment of the present invention, FIG. 5 is a top view of the same, and FIG. 6 is a Rieke diagram showing the impedance of the heating chamber. 2... Waveguide, 3... Power feeding opening, 4...
... Heating chamber, 9 ... Wing section, 10 ...
...Opening blockage.

Claims (1)

[Claims] 1. A heating chamber for irradiating high frequency waves to an object to be heated via a waveguide, an opening disposed approximately in the middle of the upper surface of the heating chamber through which the waveguide and the heating chamber communicate, and a heating chamber located opposite to this opening. The stirrer fan has a rotating shaft approximately in the center of the opening, a circular opening closing part made of a conductive material that is larger than the diagonal length of the opening, and a circular opening closing part made of a conductor that is larger than the diagonal length of the opening. A high-frequency heating device configured with a stirring blade section.