JPS5854568Y2 - High frequency heating device - Google Patents

Description

[Detailed description of the invention] This invention relates to the structure of the heating chamber of a microwave oven, in which a so-called self-cleaning layer, which performs a self-cleaning action by heating, is attached to the inner wall of the heating chamber. The purpose is also to improve the adhesion of the self-cleaning layer to the heating chamber wall.

Generally, the oven configuration of this type of microwave oven is as shown in FIG. 1, for example, when the heating source is an electric heater.

The heating chamber 1 faces a U-shaped metal side bottom wall 2, a flat metal top wall 3, and, although not shown, a rear wall and a door for attaching and detaching the heated object 4. It consists of a front wall with an opening that allows heated materials to enter and exit.

Furthermore, in FIG. 1, as a configuration for enabling high-frequency heating, an opening 5 is provided in a part of the upper wall 3, this opening is electromagnetically coupled to a high-frequency generator 6, and the heating chamber 1 is
A waveguide 7 is provided as a means for not supplying high frequency waves to other areas.

Further, an opening cover 8 made of a silicon laminate is provided to prevent foreign matter such as food scraps from entering the waveguide 7 through the opening 5.

On the other hand, a heater 9 is provided near the upper wall 3 as means for performing electrothermal heating.

However, in order to supply power to the heater, it is necessary to connect the lead wire to a power source outside the heating chamber, but if the lead wire is simply pulled out, radio waves will leak from the lead wire, so the shield case 10 (made of aluminized steel plate) must be placed around the heater. to prevent the heater and lead wires from being directly exposed to high frequency waves.

Of course, it goes without saying that this shield case is made of a mesh plate with a high aperture ratio in order to radiate heat and infrared rays.

In this example, a self-cleaning catalyst enamel 11 containing a manganese compound is coated on the heating chamber side surface of the upper wall 3 of the heating chamber.

By heating this wall surface, the oil 9 food particles that tend to adhere to the wall surface are decomposed by the action of a catalyst, thereby purifying the wall surface.

The configuration of the heating chamber of this type is already known and does not require any particular explanation.

Only the most dirty and difficult-to-clean surfaces in the heating chamber are treated with self-cleaning enamel, making it extremely easy to use.

Now, when electrical heating was performed using this heating chamber method, there was one problem.

As shown in FIG. 2, as the temperature of the heating chamber 1 gradually rises due to the lighting of the heater 9, the upper wall 3 itself thermally expands and gradually deforms due to the weight of the high frequency generator 6, etc.

Then, if the heater 9 is turned off, it returns to the original state.

In fact, a set having a heating chamber of this type is subjected to this operation repeatedly, and at this time, a very large stress is applied to the enamel layer 11 and the metal surface of the upper wall 3.

Therefore, if this process is repeated several hundred times, separation will eventually occur between the enamel 11 and the earthen wall, resulting in a very troublesome situation in which powder from the enamel 11 falls and adheres to the surface of the object to be heated during use. occured.

Figure 3 shows the situation. The present invention aims to eliminate such problems, and eliminates deformation of the upper wall 3 even during heating, thereby eliminating peeling of the enamel.

Further, in the conventional method, there was a manufacturing problem in determining when to attach the waveguide to the heating chamber.

That is, it is necessary to prevent impure substances from adhering inside the waveguide 7 as much as possible.

Even with self-cleaning enamel, sparks may occur between the waveguide 7 and the waveguide wall due to its strong electric field, and variations in the amount of adhesion may cause the operating point of the high-frequency generator 6 to vary. This becomes a factor of instability.

From this point of view, the waveguide must be installed after the earthen wall has been enameled.

On the other hand, when attaching the waveguide 7 after performing this enameling treatment, the method of attaching it became a problem.

In other words, spot welding is generally used for installation, but when spot welding is performed on the metal coated with this self-cleaning enamel, the welded area is locally heated, altering the composition of the enamel and preventing self-cleaning. This resulted in the problem that the effect was lost, and furthermore, the adhesiveness with the upper wall 3 was lost, resulting in peeling.

The present invention solves all these problems by a simple method, and FIGS. 4 to 6 show schematic diagrams of examples of the method.
Below, the installation of this heating chamber will be explained in the order in which it is attached, along with drawings.

In the present invention, first, the waveguide 7 was divided into 7-1 and 7-2, and the waveguides 7 were provided completely independently.

Conventionally, when the upper wall 3 is used as a part of the waveguide 7, it is necessary to directly spot weld the waveguide 7 and the upper wall, but according to the present invention, the self-cleaning hollow There is no need to perform spot welding at the
This eliminates the problem of adhesion.

The waveguides 71 and 7-2 are attached by spot welding 12.

Of course, this welding 12 is performed at a completely different location from the upper wall 3.

Furthermore, the waveguide 7-2 extends beyond the wall surface of the heating chamber on the side opposite to the high-frequency generator 6.

In addition, each end face parallel to the longitudinal direction of the waveguide 7-1 is 1
7 langes 13 are formed by bending about 0 mm.

The use of this flange will be described later. After forming the earthen wall into the required shape, the flange 13 of the waveguide 7-2 described above is
A pair of reinforcing metal fittings 1 are installed at a position slightly thicker than the pitch of the flange 13, approximately the width of the heating chamber 1, parallel to the flange 13, and on the side opposite to the side to which the self-cleaning enamel is applied.
4 was provided, and spot welding 15 was performed.

This reinforcing metal fitting is L-shaped so as to have a flange 16 facing the flange 13 described above.

Since this spot welding is also performed before the upper wall 3 is treated with the enamel 11, it is irrelevant to the peeling of the enamel 11.

In this state, the earthen wall is enameled.

Of course, although not shown at this time, all spot welding parts that will later form the heating chamber walls are made of enamel 11.
Needless to say, masking is applied to prevent any adhesion.

Furthermore, self-cleaning is necessary only on the heating chamber 1 side, so it goes without saying that this side is single-sided enamel.

Now, the upper wall 3 coated with the enamel 11 is spot welded to other wall surfaces forming the heating chamber at each masking part, and finally the above-mentioned waveguide 7 is attached.

In the present invention, the waveguide 7 is attached by spot welding 17 between the flanges 13 and 16 described above.

Further, the end face portion 18 of the waveguide 7-2 on the side opposite to the high frequency generator 6 was spot welded 19 to the upper wall 3 at the portion of the earthen wall outside the heating chamber.

Moreover, the opposing surface of the upper wall 3 and the waveguide 7-2 is
1 has already been attached, it is difficult to join them together by spot welding or the like.

In the present invention, a plate spring 20 made by bending a thick plate such as SUS 304 is inserted between the two, so that at least the bent part of the plate spring 20 is in contact with one surface of the two, and the end surface of the plate spring is in contact with the other surface. It seemed to come into pressure contact with the surface.

Then, in order to completely connect the opening 5 and the waveguide electromagnetically to the completed heating chamber, the area around the opening 5 was fixed with screws 19 in order to attach the opening cover 8.

Now, the heating chamber in which the present invention was implemented brought about the following effects.

First, the strength of the earthen wall is greatly improved by the flange 16 of the reinforcing metal fitting 14, and the deformation of the upper wall 3 is eliminated.

Further, spot welding 17 between the flange of the waveguide 7-2 and spot welding 17 between the waveguide 7-2 and the end face 18 of the earthen wall.
9, there is almost no distortion or deformation of the upper wall 3 at any temperature during use of the heater, and there is no peeling of the self-cleaning hollow 11 due to this deformation.

Furthermore, according to the present invention, high heat during spot welding is no longer transmitted to the surface directly coated with self-cleaning enamel, and the problem of peeling caused by this is also eliminated.

Furthermore, the following effects were produced by sandwiching the leaf spring 20 between the upper wall 3 and the waveguide 7-2 under pressure.

In other words, the electromagnetic coupling between the opening portion 5 and the waveguide is achieved by the screw 1.
9, but due to improper tightening of screws or stupidity during installation, high-frequency waves could sometimes leak from between the waveguide 7 and the earthen wall, which was dangerous in areas with strong electric fields. By implementing the present invention, even if a viscous crack occurs, the high frequency waves are reflected at the spot welds 17 and 19 and the leaf spring, and leakage from the opening no longer occurs.

In the absence of this leaf spring, we can expect a shielding effect on leakage radio waves due to the capacitance between the upper wall 3 and the waveguide 7-2, but as shown in FIG. When variations occur in the gap between the upper wall 3 and the waveguide 7-2 due to variations in time, etc., it becomes difficult to stably block leakage from this gap.

However, according to the present invention, even if this gap changes, the restoring force of the leaf spring will always maintain a short-circuited state between the two.
There was no leakage from this gap at all.

Other parts are spot welded to completely complete the upper wall 3 and waveguide 7.
-2 is coupled (short-circuited), and no leakage occurs.

As a result, even if there are no screws in the leakage scale from the opening, there will be no leakage to the outside of the main body, making the device extremely safe.

Furthermore, this opening requires only the number of screws 19 required for attaching the opening cover, making it possible to halve the number of screws and reduce production costs.

Now, this is all about this embodiment, but the self-cleaning layer in the present invention is not limited to the one in which the catalyst is attached to the heating chamber wall by enamel processing, but the same effect can be obtained in the case of the one in which the catalyst is attached by means such as painting. Needless to say, this will occur.

It goes without saying that the welding method is not limited to spot welding, but any commonly used welding method will produce the same effect.

Furthermore, it goes without saying that similar effects can be obtained even if the heating source other than high-frequency heating is electric heating or a heating method using combustion of gas, oil, or the like.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of a high-frequency heating device equipped with a heater showing a conventional example, Fig. 2 is a diagram showing deformation of the heating chamber wall when the heater is energized in the conventional example, and Fig. 3 is a diagram showing deformation in the conventional example. A diagram showing the enamel surface after repeating, FIG. 4 is a perspective view of a main part of a high-frequency heating device equipped with a heater showing an embodiment of the present invention, and FIG. 5 shows processing of the enamel surface in the same main part. Figure 6 is a cross-sectional view taken along line A-A' in Figure 5, and Figure 7 is
The figure is a sectional view taken along the line BB' in FIG. 5. 1... Heating chamber, 2... Side, bottom wall, 3...
...Top wall, 7-1.72...Waveguide, 1
1... Enamel, 12... Welding, 20
・・・・・・Plate spring.

Claims (1)

[Scope of utility model registration request] In a high-frequency heating device in which a high-frequency generator and a heating chamber are connected by a waveguide, and a layer that performs a self-purifying action by heating is provided on the wall surface of the heating chamber where a power supply opening is provided, the layer that performs the self-purifying action is provided. A high-frequency heating device characterized in that a metallic elastic body is interposed between the wall surface of the waveguide and the wall surface of the waveguide.