JPS6148237B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radio wave seal for preventing radio wave leakage from a door used in a high frequency heating device, and particularly to a radio wave seal for a door in which a portion of the door handle is embedded in the door body. This provides an improved door seal structure for.

Conventionally, most of the door handles of commercially available high-frequency heating devices such as microwave ovens are provided in a form that protrudes from the door surface, but with such a structure, the protruding handle does not touch the body during cooking. Not only is it dangerous to hit or catch a part of the door, but it is also undesirable in terms of design, so products with part or all of the handle embedded in the door body are now in demand. Summer. However, the door of a high-frequency heating device has a built-in sealing mechanism to prevent leakage of radio waves, and if the door is provided with a step or the like to inadvertently bury the handle, it will have a serious negative impact on the radio wave sealing performance. affect Therefore, the present invention solves this problem in a simple manner and provides a door with a built-in handle that has excellent radio wave sealing performance.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the entire product related to the present invention. A heating chamber 2 is provided in the main body 1, and a magnetron 3, which is a high frequency oscillator, is provided in the upper center of the heating chamber 2. The opening at the front of the heating chamber 2 can be opened and closed by a door 4. As shown in FIGS. 2 and 3, a portion of the door handle 5 is attached to the door body 6.
It is embedded in the door, and a part of the door body is recessed inward. Figure 2a
b shows the cross section of the part where the door body is squeezed, and b shows the cross section of the part where the door body is not squeezed.
A slit plate 8 is provided straddling this squeeze portion 7.

9 is a chiyoke groove having a depth of about 1/4 of the wavelength used, and as is already well known, the chiyoke is as shown in Fig. 3b.
While the slit acts to block the propagation of radio waves in the X direction, the slit acts to block propagation in the Z direction.

The height of the part of the slit plate 8 that touches the door throttle part 7 is smaller than other parts by the width of the door body's throttle, and the dimension from the bottom of the slit plate 8 to the bottom of the slit is also smaller than that of the door body. The dimension h of the portion extending over the throttle portion 7 is smaller than the dimension H of the other portion by the height R of the throttle.

That is, H≈R+h.
This means changing the dimension of H as shown by the broken line in Figure 4.
Experimental results have confirmed that the radio wave sealing performance is not very good if the dimensions are chosen such that H'<R+h, whereas the radio wave sealing performance is greatly improved by choosing the dimensions such that H≈R+h. It is for this purpose.

Conventionally, it was said that the depth of the slit should be approximately 18mm in order to have the full effect of the slit, but the depth of the slit over the squeeze part cannot be as deep as 18mm due to the limit due to the thickness of the door. Even in cases where the slit does not overlap with the diaphragm, the depth of the slit in the part that does not touch the iris tends to be larger, approximately 18 mm.

FIG. 5 shows experimental data comparing the radio wave sealing performance when only the dimension of H was changed with all other conditions being the same. Fixing h = 3.4 mm and R = 9 mm, a is H = 6.4 mm (H < h + R), and b is H = 12.4 mm (H = h + R).

As can be seen from Figure 5, in case a, the amount of radio wave leakage increases rapidly when the gap between the door and the oven becomes 4 mm or more, while in case b, even within this range, it is about 1/3 of that in case a. The amount of radio wave leakage has reached a certain level, and the effects are clearly visible.

Although the effect of the present invention is not very noticeable when the door is completely closed, when the door is opened during cooking, there is a gap between the oven and the door until the safety switch is activated and the radio wave oscillation stops. Although it is conceivable that a gap of approximately 4 mm or more may exist, even in such a case, the amount of radio wave leakage can be suppressed to a sufficiently low level in the embodiment according to the present invention. Furthermore, it is clear that a door that does not cause a sudden increase in the amount of radio wave leakage even if the gap between the door and the oven is increased, as shown in Figure 5b, is much easier to design the safety switch mentioned above and is advantageous. .

As explained above, according to the present invention, the amount of leakage of radio waves can be sufficiently suppressed to below the permissible value even when the gap between the door and the oven becomes large, even with a door of the type in which the handle is embedded in the door with a simple structure. It is possible to provide a door seal structure with good performance.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a high-frequency heating device showing one embodiment of the present invention, Fig. 2 a and b are sectional views of each embodiment of the same main part, Fig. 3 a is a perspective view of the same main part, b Figure 4 shows the direction in which radio waves travel, Figure 4 is a front view of the main slit plate, and Figure 5 is an experiment showing a comparison of the amount of radio wave leakage conducted using the embodiments a and b in Figure 2. It is data. 1...Body, 4...Door, 5...Handle,
7... Squeezing part, 8... Slit plate.

Claims (1)

[Claims] 1 The main body includes a heating chamber, a high-frequency oscillator, and a door that can freely open and close the opening of the heating chamber, and a stepped stop is formed in a part of at least one of the four sides of the door main body, and a step is formed in this part. At the same time as attaching the handle, a slit plate is provided across the step stopper, and the dimension from the wall of the door body where there is no step stopper to the bottom of the slit in the slit plate is measured from the wall surface of the door body where there is a step stopper to the bottom of the slit plate. A high-frequency heating device characterized in that the dimension to the bottom of the slit is approximately equal to the sum of the depth dimension of the step.