JPS5912595A - Door unit for electronic range - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to reducing the weight and cost of a door device for a microwave oven.

Structure of conventional example and its problems For example, in the conventional door device whose cross-sectional views are shown in Figs. A wavelength choke is essential, so either a large and heavy door is required as shown in Figure 1, or a complicated mechanism is required around the heating chamber as shown in Figure 2. was. Originally,
As long as there is a single metal plate as a door for a microwave oven,
It is possible to attach hinges, pushers, etc. to this to fulfill the door function. However, since there is a desire to see the heating chamber through the door during cooking, a method of drilling small holes in a metal plate as a means of letting light through and blocking radio waves has been widely adopted, and wires or the like are inserted into these small holes. Both sides are protected by transparent plates to prevent large amounts of radio wave leakage.

In addition, if a reliable metal contact could be made between the door and the opening of the heating chamber that faces the door, a choke would not be necessary. Chalk is required in case a dish towel or napkin gets stuck in the door.

This chalk and screen will be explained in detail below using the conventional examples shown in FIGS. 1 and 2.

Figure 1 shows a steel plate frame 1 with a thickness of about 1 mm, and a thickness of 0.2 mm.
This is an example consisting of a screen 2 made of iron plate with a diameter of about 1.5 m, transparent plates 3 made of glass provided on both sides of the screen 2, and a chalk cover 4 made of polypropylene resin. frame 1
is a large rectangular drawn product, with a rectangular opening 5 in the center and a recess 6 extending all around the opening 5.
A periodic structure 7 made of a steel plate with a thickness of approximately 0.8 mm is installed in this recess 6 by spot welding, and an opening of the same size as the opening 6 is provided just outside the opening 5. The mounting bracket 8 is attached by spot welding. The mounting bracket 8 and the periodic structure 7 are painted in a welded state. screen 2
is sandwiched between the screen fixing fitting 9 made of iron plate of about 1 w/b and the mounting fitting 8, and the fixing fitting 9 has a screw 1.
Pre-drill a hole larger than 0 in the mounting bracket 8 and a hole smaller than the screw 1o, and screw it in. One of the two transparent plates 3 is sandwiched and fixed between the mounting bracket 8 and the screen 2, and the other one is sandwiched and fixed between the screen 2 and the screen fixing bracket 9. The fixing fitting 9 has an opening 5 in the frame.
The screen 2 is provided with a group of small holes 11 for viewing in a slightly narrower area than the frontage 5. Further, in FIG. 1, the heating chamber wall 12 and the opening periphery of the heating chamber 13 are indicated by two-dot chain lines, and the inside of the heating chamber 13 is indicated by diagonal lines. Now, in the method shown in FIG. 1, the inside of the heating chamber 13 is seen through the small hole group 11 made in the screen 2 and the glass transparent plate 3 provided on both sides of the hole group 11, and the chalk is provided in the frame 1. Mounting bracket 8. Fixing bracket 9. A recess 14 in the frame 1 surrounded by a portion of the screen 2 sandwiched between the mounting bracket 8 and the fixing bracket 9 plays this role. The periodic structure 7 is provided to improve the radio wave leakage prevention performance of this choke.0 In the example shown in Figure 2, the door has a thin iron screen 2 sandwiched in between, and one side is made of glass. On the opposite side of the transparent plate 3 is a transparent plate 15 made of a thin polycarbonate resin sheet.These three plates have almost the same external dimensions, and in order to fix the three plates, an aluminum sash 16 is attached to the entire outer periphery. The screen 2 is provided with a group of small holes 11 for viewing through the circumference.
can be opened. This door has a see-through feature but no choke. Although the opening peripheries of the heating chamber wall 12 and the heating chamber 13 are shown by two-dot chain lines, a recess 14 is provided around the entire periphery of the opening, and the inside is filled with polypropylene resin 17. This has a choke function.

As can be clearly seen by comparing Figures 1 and 2 above, if the choke function is installed on the door, the door becomes complicated and heavy, and if it is installed on the heating chamber side, the heating chamber becomes complicated. OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and aims to reduce the weight and cost of a door equipped with a choke function.

Structure of the Invention In order to achieve the above object, the microwave oven door of the present invention has the following features:
Two large and small thin metal plates A and B are brought into contact and fixed in a closed line by means such as welding, and a see-through means such as a group of small holes is provided inside this closed line, and a dielectric sheet is placed on the outside. C to A
, H, and this ABC is sandwiched between two transparent dielectric plates.A microwave oven door with a choke function can be made thinner and lighter, and the number of parts can be reduced, resulting in low cost. This has the effect of making it more affordable.

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

FIG. 3 is a sectional view of a main part of the door of this embodiment, and FIG. 4 is an exploded perspective view. In order to make it easier to understand,
Parts having the same functions as those of the conventional example shown in FIGS. 1 and 2 are given the same numbers. The metal plates A1s and B2 made of stainless steel 5US304 with a size of about 100 to 2 QO microns have a rectangular outer shape, with A18 being slightly larger than B2, and having roughly similar shapes.

The metal plate A18 has a large rectangular opening 19 in the center,
Around the opening 19, a step 6 of about 2QO microns is provided in a rectangular shape slightly larger than the opening 19. The four corners between the opening 19 and the step 6 are cut out.

The end portion 2o is bent on all four sides, and a number of notches (slits) 21 are provided here.

The metal plate B2 has a group of small holes 11 in the center in a range approximately the same size as the opening 19, and cutouts (slits) 22 are provided at equal intervals on the outer periphery. Dielectric sheet) C17 is made of polytetrafluoroethylene resin and has a thickness of approximately 200 microns.
The outer shape is approximately the same size as the metal plate A18, and a rectangular opening 23 is provided in the center. The size of the opening 23 is the same as the step 6.
The dimensions shall be slightly larger than the above. With the step 6 and the opening 23 fitted, the metal plates A18 and B2 are spot welded, and the dielectric sheet c17 is sandwiched between the metal plates A18 and B2. The welding positions are the metal plate A18 between the opening 19 and the step 6, and the metal plate B2 just outside the small hole group 11.
Welding is performed with the opening 19 and the small hole group 11 aligned.

The spacer 24 is a transparent resin plate made of polycarbonate or the like, and has an external dimension slightly smaller than the opening 19.

The transparent dielectric plate 3 made of heat-strengthened glass has outer dimensions slightly smaller than the metal plate A18.

The transparent dielectric sheet (Dl 5) made of polyester resin and having a diameter of about 100 microns has the same external dimensions as the transparent dielectric plate 3.

Now, metal plate A18. B2 and the dielectric sheet C17 sandwiched between them are sandwiched from both sides by the two transparent dielectrics, the transparent dielectric plate 3 and the transparent dielectric sheet D15,
The surrounding area is fixed with an aluminum sash 16. The spacer 24 is inserted into the opening 19 and is sandwiched between the transparent dielectric plate 3 and the portion of the small hole group 11 of the metal plate B2. Further, the end portion 2o of the metal plate A18 is bent on all four sides as described above, and the transparent dielectric plate 3 is fixed in a state inserted into these four bent portions. As shown in FIG. 4, the sash 16 is bent at right angles at four places and abutted on the left side to form a rectangular picture frame shape.

A hole 26 made in the hinge fitting 25 and a hole (not shown) made in the sash 16 are screwed together, and the sash 16 is fixed. Although the end portion 2o of the metal plate A18 is bent, it is in contact with the sash 16 due to a spring bank generated during the bending process, as is well known.

The operation of the above configuration will be explained below.

Of the two functions explained in the conventional example, the see-through function is the small hole group of the metal plate A18 and the spacers 24 provided on both sides thereof. Transparent dielectric plate 3. Transparent dielectric sheet) Dl 5-3
Filled with transparent plates.

Similar to the conventional example shown in Figure 2, the small hole group is protected on both sides by transparent plates, which provides sufficient mechanical strength and prevents wires, etc., from being inserted into the small holes. It is also possible to prevent radio wave leakage.

The choke function is fulfilled by three metal plates A1 B and B2 and a dielectric sheet C17. In other words, the line of % wavelength is connected to two metal plates A18 facing each other via dielectric sheet C1.
and B2, and the terminal end of the line, the short-circuit end, is the metal plate A
This is obtained by spot welding 18 and B2. The choke opening is formed by insulating the ends of the metal plates A18 and B2 with a dielectric notebook. In this embodiment, since the sash 16 is made of metal, a notch 21 is provided at the end of the metal plate A18, which is bent and comes into contact with the sash 16, so that the sash 16 also forms a part of the choke. ing.

In addition, there are notches (slits) 2 at equal intervals on the end of the metal plate B2.
As is well known, this periodic structure 7 has the same function as the conventional periodic structure 7 shown in FIG. 1, and greatly enhances the radio wave leakage prevention effect. The thickness of this metal plate B2 is 100 to 200 microns, and the slit part in particular is mechanically very weak, but since it is protected by a transparent dielectric 3 made of tempered glass and a dielectric sheet D15, Sufficient mechanical strength can be obtained. Note that the dielectric sheet D1
It is effective to use adhesive on one side of 5 to fix it to the metal plate B2.

In this embodiment, a group of small holes 11 is provided in the metal plate B2,
Although the opening 19 is provided in the metal plate A18 in the corresponding part, it is also possible to provide a group of small holes in the metal plate A18 and the opening in the metal plate B2 in the corresponding part. in this case,
The spacer may be removed or provided on the side of the dielectric sheet D16. Alternatively, groups of small holes may be provided in both metal plates A18 and B2, and the positions of the small holes may be made to coincide with each other.

As can be seen from the comparison between FIG. 2 and FIG. 3, this embodiment has almost the same thickness and weight as the conventional example shown in FIG. It can have a similar radio wave leakage prevention function.

As is clear from a comparison between FIG. 1 and FIG. 3, this embodiment does not have the thick and heavy frame 16 shown in FIG. It is possible to realize a door with

Furthermore, in the example shown in Figure 1, the surface of the door is uneven, and although it has an excellent radio wave leakage prevention function, it is a major drawback in terms of design. Similarly, doors with flat surfaces can be realized. Furthermore, although the door in the example of Fig. 1 and the periphery of the opening of the heating chamber in the example of Fig. 2 are complicated and require large structures, in this embodiment, both are unnecessary, and the material cost and assembly cost can be reduced accordingly. As described above, according to the present invention, the following effects can be obtained.

(1) A thin and lightweight microwave oven door device having a high-performance radio wave leakage prevention function can be realized.

2) A flat door with an excellent design and a high-performance radio wave leakage prevention function can be realized.

(3) The cost of the door and choke function can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of the main part of a conventional microwave oven door device, Fig. 2 is a side sectional view of the main part showing another conventional example, and Fig. 3 is a microwave oven door device according to an embodiment of the present invention. FIG. 4 is a side sectional view of the main part of the door device, and FIG. 4 is an exploded perspective view thereof. 2...Metal plate B (iron plate screen), 3...
...Transparent dielectric plate, 11...Small hole group, 13
... Heating chamber, 15 ... Transparent dielectric sheet D, 17 ... Dielectric sheet C, 18 ...
...Metal plate A119...Opening. Name of agent: Patent attorney Toshio Nakao and 1 other person 48
2- Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A transparent dielectric plate provided on the outside of the door, two thin metal plates A and B, and two thin dielectric sheets C and D.
The metal plate A is slightly larger than the metal plate B, and a group of small holes for seeing through is provided in the center of at least one of the metal plates A and B, and a group of small holes for seeing through the other are provided in the center part of at least one of the metal plates A and B, and a group of small holes for seeing through are provided in the other side. groups or openings are provided at corresponding positions, and the metal plates A and B are fixed in contact with each other in a line surrounding the group of small holes for see-through immediately outside the group of small holes for see-through, and further outside the group of small holes for see-through. inserts the dielectric sheet C between the metal plates A and B, insulates the ends of the metal plates A and B, and
Also, a door device for a microwave oven having a structure in which a dielectric sheet c is sandwiched between the transparent dielectric plate and the transparent dielectric sheet D.