JPH01175196A - High-frequency heater - Google Patents

Abstract

PURPOSE:To improve radio wave leakage preventing performance for a long term by providing a first metal plate which, on closing a door, the box part thereof projects into a heating chamber and the side of the box is located in parallel to the heating chamber. CONSTITUTION:In closing a door, a heat insulating member 31 is fixedly clamped between the end of the periphery 19 of a metal plate 18 and a thin grooved recess 27 of a door main body. A slit plate 16 is accommodated into a groove formed with a metal plates 11, 18 and opening 32 of the groove is located apart from the inside of the heating chamber. The foreign matter of food in the inside of the heating chamber is less intend to enter in the groove and therefore never adhere on a periodic structure so that it is possible to improve radio wave leakage preventing performance for a long term.

Description

[Detailed description of the invention] Industrial applications The present invention relates to improvements in microwave ovens.

BACKGROUND OF THE INVENTION In the past, a large number of technologies have been announced regarding the prevention of radio wave leakage from the door of a microwave oven, and there are also many examples of commercialization. However, in the case of microwave ovens with self-cleaning openings that are widely used in Europe and the United States, the technology that has been put to practical use is extremely limited, and the only practical example is shown in Figure 9. This situation is no exaggeration.

In this method, a choke is protruded into the open refrigerator, and notches (slits) 15 are periodically provided on the wall of the choke, so that the ability to prevent radio wave leakage is less degraded when the door is slightly opened. This is a useful technique when used at high temperatures.

The problem that the invention seeks to solve However, this technique also has major drawbacks.

The first is that it is weak. This is an inevitable result from a structural standpoint, but since the slits 15 are cut, each component is weak, and since it is located at a position where the user's hands can touch it, it is easy to accidentally deform it. is common.

If it is deformed, the radio wave leakage prevention performance will naturally decrease.
In some cases, a large amount of leakage may exceed the standard.

Secondly, there is a drawback of the slit 16 itself.

A microwave oven is a food heating device that heats various foods. Some of them, such as eggs, burst during heating and scatter, while others, such as miso soup, milk, and coffee, overheat only at the top of the container and boil over, resulting in food waste. However, if food waste is left in the slit and used for a long period of time, the food waste will eventually carbonize and cause sparks due to the strong microwave electric field in the slit. . At the same time, the radio wave leakage prevention function is also greatly reduced.

Thirdly, there are manufacturing and cost problems.

As shown in Figures 2 and 10, the slits are provided at equal intervals over the entire side surface of the box-shaped container, and are generally provided at the apex of some of the corners. ), as shown in Figure 10, it is necessary to perform press working from eight directions from the D direction to the direction. There was also a problem in that the difference in finished dimension of the slit due to the difference led to a decrease in radio wave leakage prevention characteristics.

The present invention aims to solve the above-mentioned three drawbacks of the prior art, and aims to (1) improve strength, (2) prevent food debris from adhering, and (3) simplify work (process). I'm trying to figure it out.

Means for Solving the Problems Therefore, the present invention provides a first shallow box-shaped first door that is attached to the door that blocks the opening of the heating chamber so as to protrude into the heating chamber.
The metal plate is electrically connected to a shallow box-shaped second metal plate that is housed and fixed in the box of the first metal plate, and the first and second metal plates are connected electrically. A configuration in which a metal periodic structure is housed in a groove formed by a plate, and in this configuration, the periodic structure is made from two long and thin metal plates, and one side of the metal plate has notches (slits) at equal intervals. established,
The opposite side is welded to the first metal plate.

Effect: As a result of the above structure, the periodic structure is housed inside the groove formed by the first and second metal plates, so it is protected from abnormal forces accidentally applied from the outside and is less likely to deform.

Furthermore, various shapes of periodic structures have been proposed in the past, but as the structure becomes more complex, its mechanical strength decreases, making it difficult to install it in a position that can be touched by people's hands. Although this was not possible, these complex methods with better radio wave leakage prevention performance can now be adopted.

Furthermore, as a result of the above configuration, the periodic structure is housed inside the groove formed by the first and second metal plates, and the opening of the groove is open in the direction facing away from the heating chamber. The possibility of food debris generated indoors becoming resistant to the periodic structure is significantly reduced.

In addition, since periodic structures are made by providing notches (slits) at equal intervals on one side of a long and thin metal plate, and then bending and welding, the work of providing the slits can be done in one press operation. Compared to the method of pressing from eight directions, it is possible to create highly accurate slits with less variation, and at the same time, the reduction in the number of pressing directions also means a reduction in work costs.

Example Examples will be described below with reference to the drawings.

FIG. 2 is an external perspective view of one embodiment of the present invention, showing a state in which the door is slightly opened. This high frequency heating device has a door 1. Heating chamber 2. Metal body 3. Intake grill (grid) 4. Exhaust grill5. It consists of an operation part 6, etc., and a door handle 7 on the top of the door 1.
and a key 8 are provided.

FIG. 3 is a perspective view of the door 1 when it is opened. However, the above-mentioned key 8 and hinge, etc., which should originally be attached to the door, are well-known techniques and are not directly related to the gist of the present application, so the drawing It is omitted above.

The door 1 has a thin box-shaped metal plate 1 that is press-processed from sheet metal.
1. Glass plate 12. A thin box-shaped door body 13 made of sheet metal and pressed, and a glass plate B14 provided on the outside of the door body. Furthermore, it consists of the above-mentioned resin handle 7 and the like.

In order to facilitate comparison with the conventional example, FIG. 9 has been prepared in contrast to FIG. 3. In the prior art shown in FIG. 9, slits (cutouts) 16 are provided at equal intervals on the side surface of the metal plate 11 in FIG. 3 of the embodiment of the present application.

FIG. 1 is an exploded perspective view showing the door of FIG. 3 in an exploded state. The metal plate 11 is shown in a partially cutaway view in FIG. 1, but as can be easily understood from this, a slit plate 16 is welded to the inside of the shallow box shape, and this slit plate is shown in FIG. As in the conventional example, slits 15 are provided at equal intervals.

Further, an opening 17 is formed in the bottom of the box of the metal plate 11.

With the slit plate 16 welded, the metal plate 11 is enameled. However, the bottom part of the inside of the box shape is subjected to a so-called masking process to prevent the enamel layer from adhering.

The metal plate 18 is pressed into a shallow box shape and has a frame-like periphery 19 around the periphery. A recess 2o is provided at the bottom of the shallow box over a slightly wider area than the glass plate 12 described above,
A small hole group 21 is provided in the center of this recess in a slightly narrower area than the glass plate 12. The range (size) of this small hole group 21 is made approximately equal to the opening 17 of the metal plate 11. metal plate 1
8 is subjected to enamel treatment. However, on the outside of the shallow box-shaped bottom,
The shaded area in Figure 1 is designed to prevent enamel from adhering to the area.
Apply so-called masking. The metal plates 11 and 18 are connected to each other by inserting the shallow box of the metal plate 18 into the shallow box of the metal plate 11 and attaching the metal plates 11 and 18 using a plurality of screws 22.
and fix it with nut 23.

The screws 22 are installed at positions corresponding to the metal plates 11 and 18, respectively.
Needless to say, holes 24 and 25 are provided for the passage of the screws. Only some of the screws, nuts, and holes 24 and 25 are shown in Figure 1. As mentioned above, the contact surfaces of the metal plates 11 and 18 do not have enamel attached to them. However, the surface is oxidized due to the high temperature during enamel processing, and it is not always possible to obtain a sufficient direct current connection. It is well known to those skilled in the art that connections can be made.

The glass plate 12 is housed in the recess 2o.

The door body 13 is a shallow box-shaped metal plate, which is formed by press working and painted. An opening 26 is formed in the center, and the size (range) of this opening 26 is equal to that of the opening 17, and is provided at a position where they can be overlapped when assembled by the method described later. A narrow groove-shaped recess 27 is provided all around the outside of this opening 26, and the positions of these four parts are aligned with the end of the outer peripheral edge 19 of the metal plate 18. Also, the lower side of the door body 13 (
A long and narrow slit 28 is provided on the left and right sides (the side that becomes the bottom when the door is closed), and the omitted hinge mechanism is attached to this part. (Details omitted) Door body 13 and metal plate 11.
18 is fixed using a plurality of screws 29 and nuts 30. However, in the figure, the nut 30 is drawn below the glass plate 14 for convenience.

The glass plate 14 is fixed to the door body using small auxiliary fittings or the like. (Details omitted) Fix the handle to the door body with screws, etc.

FIG. 4 is a perspective view of the slit plate 16. In this embodiment, two of these are used and spot welded to the metal plate 11.

FIG. 6 is a developed view of the slit plate 16 shown in FIG. 4, and after the slit plate is stamped from a flat plate into the shape shown in FIG. -C' is bent and formed into the shape shown in Fig. 4.

FIG. 6 is a plan view showing the positional relationship between the slit plate 16 and the metal plate 11, where the metal plate 11 is indicated by a two-dot chain line.

FIG. 10 is a plan view of the metal plate 11 of the conventional example drawn in comparison with FIG. 6 in order to clarify the problems of the conventional example. ...J.

A press-joint slit 15 is provided from the direction of expression in the 8 letters K.

FIG. 7 is a sectional view of the end of the door 1 in the closed state. Although omitted in FIG. 1 because it is complicated, a heat insulating material 31 is inserted and fixed between the end of the peripheral edge 19 of the metal plate 18 and the narrow groove-shaped recess 2 of the door body. The insulation material 31 is made of glass fiber braided tubing. As can be clearly understood from this figure, the slit plate 16 is connected to the metal plate 1.
1 and the metal plate 18, and it can be seen that the opening 32 of this groove is located away from the interior of the heating chamber 2.

FIG. 11 is a sectional view of a conventional example shown in comparison with FIG. 7. Here, the effects of the present application will be described again.

In FIGS. 11 and 7, small arrows drawn inside the heating chamber indicate the direction of the high-frequency electric field within the chamber.

Generally, high-frequency heating devices are provided with a stirring device, and the electric field within the refrigerator is therefore oriented in various directions. In the conventional example shown in FIG. 11, the incidence angle of the radio waves incident on the slit 15 is 3
2, but the direction of the electric field entering this entrance already indicates various directions.

In other words, it can be said that the impedance of radio waves incident on this choke has various values.

On the other hand, in the embodiment of the present application shown in FIG. 10, the electric fields oriented in various directions in the heating chamber as in FIG. While traveling between the metal plates, the electric field is confined only in the direction perpendicular to both metal plates. Therefore, the impedance of the radio wave when it enters the choke entrance 32 is limited to a limited range of values. In other words, it becomes easier to design the teeth, and an effective choke can be designed easily. In other words, choke impedance matching can be easily performed.

FIG. 8 is a partial perspective view showing another embodiment of the slit plate 16 shown in FIG. This periodic structure is known to be highly effective with small dimensions, but as can be easily seen from the figure, it is mechanically weak, so it cannot be used in areas that come in contact with people's hands. It was virtually impossible. In this regard, in the present application, the periodic structure is housed in the groove formed by the metal plates 11 and 18, so it cannot be easily touched by human hands. In other words, a smaller and more effective radio wave leakage prevention mechanism can be realized.

Effects of the Invention Since the periodic structure is housed in the groove made of the two shallow box-shaped first and second metal plates, the periodic structure with weak mechanical strength is protected and stable radio waves can be obtained for a long period of time. A high-frequency heating device with leakage prevention performance can be realized.

The first metal plate protrudes into the heating chamber, and the heating chamber wall and the side surface of the box (the side surface portion of the shallow box-shaped first metal plate when viewed as a box) are positioned parallel to each other. Since the opening 32 of the groove made of the metal plate No. 2 is located in a direction away from the inside of the heating chamber, it is difficult for food particles generated from inside the chamber to enter the groove, and therefore, it does not stick to the periodic structure. It is possible to maintain radio wave leakage prevention performance for a period of time.

In addition, since the periodic structure is made from two long and thin metal plates, and the slits are pressed at once, highly accurate slits with little variation can be easily obtained, which is useful for improving radio wave leakage prevention performance and improving productivity. It also helps reduce costs.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a door according to an embodiment of the present invention, FIG. 2 is a perspective view of a high-frequency heating device according to an embodiment of the present invention, FIG. 3 is a perspective view of the opening door, and FIG. Perspective view of the same slit plate, No. 6
The figure is a developed view of the slit plate, Figure 6 is a plan view of the metal plate, Figure 7 is a sectional view showing the end of the metal plate, and Figure 8 is a portion of the periodic structure of the pond embodiment of the present invention. FIG. 9 is a perspective view of a conventional door, FIG. 10 is a plan view of the same metal plate, and FIG. 11 is a sectional view of the end of the same. 11.18...Metal plate, 16...Slit, 16...Slit plate. Name of agent: Patent attorney Toshio Nakao and 1 other person11
---Slit No. 5--Slit No. 1 Figure 1 1lt-4 Figure 2 Figure 3 Figure 5 WJ7 Figure 8 Figure 9 Figure 10 and Figure 11

Claims (2)

[Claims] (1) It has a box-shaped first metal plate, a box-shaped second metal plate having a frame-like part, a shallow box-shaped door body, and a heating chamber, and The box part of the second metal plate is housed in the box part, the first and second metal plates are connected at high frequency, and the groove formed by the first and second metal plates is A metal periodic structure is housed therein, and when the door, which is composed of the door body, the first metal plate, and the second metal plate, is closed, the first metal plate closes the box. a portion protrudes into the heating chamber, and a heating chamber wall;
A high-frequency heating device characterized in that it is configured such that the side surface of the box is positioned substantially parallel to the side surface of the box. (2) The periodic structure consists of two long and thin metal plates, with cutouts (slits) provided at equal intervals on one side of the metal plate.
2. The high frequency heating device according to claim 1, wherein the opposite side is welded to the first metal plate.