JPS6338614B2 - - Google Patents

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to a microwave oven door.

(b) Prior art Figures 1 to 3 show the door 1 of a conventional microwave oven.
The door opens and closes the front opening 4 of the heating chamber 3 located inside the microwave oven main body 2. To explain the structure of the door 1, the central opening 5
A metal door body 6 having a U-shaped cross section and a frame shape is provided, and a metal door inner plate 7 is provided. The door inner plate includes a rectangular microwave shielding part 9 consisting of a large number of punched holes 8, 8, . It consists of an outer peripheral part 10 narrowed to a depth d (=4 mm) in a frame shape in the direction of the peripheral plate 4', and an intermediate part 11 located between the intended microwave shielding part 9 and the outer peripheral part 10. There is. The door inner plate 7 is fixed to the door body 6 by projection welding the intermediate portion 11 to the inner edge 6' of the door body 6 (X location in FIG. 2), and the microwave The shielding part 9 faces the central opening 5 and serves as a viewing window for looking into the heating chamber 3. Furthermore, the outer peripheral part 10 forms a microwave cooling space 12 together with the door body 6, and when the door 1 is closed, the peripheral edge It is designed to actively abut (metallic contact) on the plate 4'. or,
The cavity space 12 is closed with a microwave transparent dielectric 13, and a microwave absorber 14 such as ferrite is fixed to the dielectric.
Further, the microwave shielding section 9 is covered with a transparent sheet 15, and a transparent panel 16 is arranged on the front surface of the door body 6. Here, heating chamber 3
Microwaves inside are significantly suppressed from leaking to the outside due to the metal contact between the peripheral plate 4' of the front opening 4 and the outer circumferential portion 10, the yoke space 12, and the microwave absorber 14.

Now, the above-mentioned aperture was implemented in the 49th century.
As can be seen in Japanese Patent No. 26764, when constricting in this way, the dimension between the corner 9' of the microwave shielding part 9 and the corner 10' of the outer peripheral part 10, that is, the width of the intermediate part 11 is The dimension t of the corner 11' is as follows:
It is necessary to secure at least 15 to 20 mm. That is,
If the dimension t is quite small, for example 8 mm, then
When narrowing down, a large force acts on the corner 9' of the microwave shielding part 9 in the directions of arrows A, B, and C (Fig. 2).
Then, as shown in detail in FIG. 3, at the corner 9' of the microwave shielding part 9, the small holes 8, 8... deform into an elliptical shape in the direction of the arrow a, creating a crack K, and microwaves are transmitted from this part. leaks outside and is extremely dangerous.

However, if the dimension t is set at 15 to 20 mm as described above, the area of the microwave shielding part 9 must be made that much smaller, and in such a case, the part that looks into the heating chamber 3 is small. There is a drawback to this.

(C) Object of the Invention The object of the present invention is to provide a door inner plate having a rectangular microwave shielding part consisting of a large number of small holes through which microwaves cannot pass, and an outer peripheral part located on the outer periphery of the microwave shielding part. Increasing the area of the microwave shielding part through which the inside of the heating chamber can be seen, and in this case, preventing the formation of cracks in the small hole when the outer periphery is squeezed into a frame shape in the direction of the peripheral plate of the heating chamber opening. It's about doing.

(D) Structure of the Invention In order to achieve the above object, the present invention provides a frame-shaped door body having a central opening, and a short door body comprising a large number of small holes facing the central opening of the door body through which microwaves cannot pass. A door inner plate having a shaped microwave shielding part and an outer periphery located on the outer periphery of the microwave shielding part, the outer periphery of the door inner plate is narrowed into a frame shape, and when the door is closed, the periphery of the heating chamber opening In the microwave oven door that abuts the plate, the depth of the frame-shaped aperture formed between each corner of the microwave shielding part and the outer peripheral part of the door inner plate before the formation of the frame-shaped aperture is further increased. It has protrusions that are smaller in depth than the

(e) Embodiment FIG. 4 shows the main parts of a microwave oven door according to an embodiment of the present invention. Incidentally, the same parts as in the conventional example are denoted by the same reference numerals, and the explanation thereof will be omitted.

The feature of this door is that when the outer peripheral part 10 located on the outer periphery of the microwave shielding part 9 is narrowed in the direction of the peripheral plate 4' of the front opening 4 in the direction of the peripheral plate 4' of the front opening 4 in the door inner plate 7, A protrusion 17 having a depth smaller than the aperture depth d is formed between the corners 9' and 10' of the microwave shielding part 9 and the outer peripheral part 10, that is, at the corner 11' of the intermediate part 11. There is a particular thing. Specifically, the protrusion 17 is formed before the frame-shaped drawing is performed, more specifically, at the same time as the drawing. In this case, the appropriate drawing depth of the protrusion 17 is 0.1 to 1.0 mm, preferably 0.3 mm.

Here, in forming the projection 17,
The corner 11' of the intermediate part 11 is locally pinched by the squeezing machine, and when it is squeezed to the above depth d, the corner 9' of the microwave shielding part 9 is marked with arrows A, B,
It is possible to suppress a large force from acting in the C direction. In this case, a force in the directions of arrows A, B, and C is exerted on the corner portion 9' of the microwave shielding part 9 due to the aperture formation of the protrusion 17, but such force is caused by the aperture depth dimension of the protrusion 17.
Since it is only about 0.1 to 1.0 mm, it is small, and therefore the punched small holes 8, 8 of the microwave shielding part 9 will not be cracked.

By forming the protrusion 17 with aperture, it is possible to suppress the action of undesired force on the corner 9' of the microwave shielding part 9, so that the corner 9' of the microwave shielding part 9 and the outer peripheral part 10 are The dimension t between the corner portion 10', that is, the dimension t of the intermediate portion 11, can be reduced from the conventional 15 to 20 mm to, for example, about 8 mm. The area can be increased.

Although the projections 17 are formed continuously so as to surround the corner 9' of the microwave shielding section 9, they may be formed intermittently.

Furthermore, the projections 17 formed as described above are then covered with a transparent sheet 15 for covering the microwave shielding part 9.
Can be used for positioning when pasting.
Alternatively, such protrusions 17 can be removed by pressing or the like after that, and the intermediate portion 11 can be made into a uniform surface. In this case, the intermediate portion 11 is connected to the inner edge 6' of the door body 6.
It is possible to prevent the protrusion 17 from getting in the way when projection welding (X location) is performed, and the appearance is also favorable since there is no unevenness.

(F) Effects of the Invention According to the microwave oven door of the present invention, the door has a rectangular microwave shielding portion consisting of a large number of small holes through which microwaves cannot pass, and an outer peripheral portion located on the outer periphery of the microwave shielding portion. In the inner plate, the area of the microwave shielding part through which the inside of the heating chamber can be seen can be increased, and in this case, it is possible to prevent cracks from forming in the small holes when narrowing the outer peripheral part into a frame shape, thereby preventing microwave leakage. can be prevented from occurring.

[Brief explanation of drawings]

1 to 3 show a conventional microwave oven door, FIG. 1 is a cross-sectional view, FIG. 2 is a plan view of the inner panel of the door, and FIG. 3 is an enlarged plan view of the part in FIG.
FIG. 4 is a plan view of the inner plate of the microwave oven door according to the embodiment of the present invention. 1...Door, 5...Central opening, 6...Door body, 7...Door inner plate, 8...Punching small hole, 9
...Microwave shielding part, 10...Outer peripheral part, 17...
…protrusion.

Claims (1)

[Claims] 1. A frame-shaped door body with a central opening, a rectangular microwave shielding part consisting of a large number of small holes that face the central opening of the door body and through which microwaves cannot pass, and a microwave shielding part located on the outer periphery of the microwave shielding part. a door inner plate having an outer periphery, the outer periphery of the door inner plate is narrowed into a frame shape, and the door of the microwave oven abuts against a periphery plate of a heating chamber opening when the door is closed;
Furthermore, between each corner of the microwave shielding part and the outer peripheral part of the door inner plate, there is a protrusion having a depth smaller than the depth of the frame-shaped aperture, which is formed before the frame-shaped aperture is formed. A microwave oven door characterized by: