JPH0472340B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetron having a filter case that can be easily manufactured using a simple technique and with a small number of man-hours.

Figures 1 and 2 show conventional magnetron filter cases, with Figure 1 showing a deep-drawn press product and Figure 2 showing a case with the four bottom sides bent and the four side corners fixed by spot welding. What is shown in Figure 1 is 1
Although it is formed by a deep drawing process, it requires advanced technology and cracks are likely to occur in the corner portion 4. If these cracks are overlooked in use, the amount of leakage radiation of unnecessary microwaves will increase. Further, the portion where the burring hole 3 for fixing the capacitor is provided is made thinner than the original thickness of the material plate during deep drawing, and there is a problem that it is difficult to obtain the required burring height. In addition, in Figure 1,
1 is a caulking flange attached to the case lid, and 2 is a capacitor installation port. Although the spot welded product shown in Figure 2 does not have any technical difficulties, it requires spot welding at a sufficiently large number of points to suppress unnecessary microwave leakage, resulting in a large number of man-hours and a high cost. There is a problem. In FIG. 2, numeral 5 indicates a bent portion, and numeral 6 indicates a spot welding point.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive magnetron having a filter case that can be simply and easily formed by solving the above-mentioned problems encountered in the conventional magnetron filter case.

In order to achieve the above object, in the present invention,
I bent the four sides of the bottom and bent and caulked the four corners of the sides to secure it in place.

FIG. 3 is a diagram showing a filter case according to the present invention. In the figure, 5 is a bent portion, and 7 is a bent and caulked fixing portion. The filter case according to the present invention does not require particularly sophisticated or difficult technology, and can be manufactured extremely easily and at low cost. Since caulking is performed on the entire caulking fixing part, there is no fear of unnecessary microwave leakage radiation. That is, as shown in Fig. 4, if the distance d between the caulking points is 5 mm or less, the fifth
It is possible to prevent leakage of unnecessary microwaves up to harmonics. Incidentally, the fifth harmonic is 12.5 gigahertz and the wavelength λ is 24 mm. Therefore, λ/4
is 6 mm, so if the distance between the caulking points is 6 mm or less, leakage of microwaves up to the fifth harmonic can be prevented. Compared to spot welding, it requires fewer man-hours, works reliably, and is highly reliable. Since no drawing work is performed, the wall thickness at the location where the burring hole 3 for fixing the capacitor is provided is not different from the material plate thickness. In the case of deep-drawn products, a relatively thick material plate is required to ensure the wall thickness at the burring hole location, but in the case of the present invention, a relatively thin material plate, for example, a 0.3 mm thick steel plate, can be used. I can do it. Here, the state of caulking in the present invention will be explained using a developed view. FIG. 5 shows a developed view of the folding process. First, the caulking flange 1 is bent as shown in the figure, and a U-shape is formed at the tip of the plate material 11 to be caulked. Next, B ₃ in the same figure,
B Fold sides A and A′ by 90° at position ₄ . similarly
Fold planes B and B' by 90° at positions B ₁ and B ₂ . Next, put the protruding surface at the tip of the plate material 12 shown in the same figure into the U-shaped groove of the U-shaped part 11, and in this state, the U-shaped part 11
As shown in FIG. 3, by caulking the character-shaped portion, it is joined to the 12 protruding surfaces. When 11 and 12 are meshed together, there will be a slight gap in the filter case near the bent part, but this gap will not cause any problem with unnecessary microwave leakage radiation. be. This is because in microwave ovens, which are the main application of magnetrons, the fifth harmonic has a large amount of radio wave leakage.
This is because the desired shielding effect can be obtained against leakage up to 12.5 GHz by setting the thickness to λ/4, that is, about 6 mm or less (corresponding to about 12 times the normal plate thickness or less). Incidentally, it is impossible to make the distance zero with the structure of the present invention.

As explained above, according to the present invention, a filter case can be manufactured easily with a simple technique and with a small number of man-hours, resulting in a low cost, and the product is highly reliable, and unnecessary harmonic radiation is reliably prevented. It can be suppressed.

[Brief explanation of drawings]

Fig. 1 shows a filter case formed by deep drawing, Fig. 2 shows a filter case formed by bending and spot welding, Fig. 3 shows a filter case according to the present invention, and Fig. 4 shows a filter case formed by bending and spot welding. The figure is a detailed view of the caulking portion according to the present invention, and FIG. 5 is a developed view showing the condition of the caulking according to the present invention. 3... Burring hole for fixing the capacitor, 4...
corner part, 5... bending part, 7... bending caulking fixing part, 10... caulking point, 11, 12... plate material to be caulked.

Claims (1)

[Claims] 1. In a magnetron equipped with a filter case that houses a capacitor and a chiyoke coil for suppressing unnecessary radiation, the filter case is separated from a single plate by bending the four sides of the bottom and bending and caulking the four corners of the side. A magnetron having a box-like shape, wherein the caulking is performed on the entire caulking fixing part.