JPS645437B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a high-frequency heating device having a high-frequency heating function, and relates to a structure of a waveguide for guiding high-frequency waves into a heating chamber and a top plate of the heating chamber.

Structure of a conventional example and its problems FIG. 1 is a cross-sectional view showing the structure of a conventional high-frequency heating device. In FIG. 1, an upper heater 2 is provided at the upper part of a heating chamber 1 to be used for heater heating. 3 is a magnetron that supplies high frequency waves into the heating chamber 1. The high frequency waves oscillated by the magnetron 3 pass through a space between a box-shaped upper waveguide plate 4 and a lower waveguide plate 5 that form a waveguide. It is guided into the heating chamber 1 through a power feeding opening 7 provided in an upper plate 6 forming the heating chamber 1, and heats an object to be heated 8 within the heating chamber 1.

A shielding member 9 is provided in the opening 7 of the heating chamber upper plate 6 to prevent food particles, oil, etc. from entering the waveguide and causing sparks during high-frequency heating.
is fixed to the surface of the heating chamber upper plate 6 with mounting screws 10. The shielding member 10 is generally made of a heat-resistant mica board with low high-frequency loss (hereinafter, the shielding member 10 will be referred to as a mica board).

The details of the above configuration will be explained with reference to FIG. 2, which is an enlarged sectional view of the mounting structure of the mica plate 10. The waveguide upper plate 4, the waveguide lower plate 5, and the heating chamber upper plate 6 are made of aluminized steel plates that are relatively resistant to corrosion by the heat generated when heater heating is performed using the upper heater 2. There is. This has an iron base 11 made of an aluminized steel plate in the center, and the surface is aluminized 12. However, the end surface portion 13
When processing into an arbitrary shape, the iron base 11 is exposed because it is cut by press working. Since oxygen, sulfur, nitrogen, water vapor, and various other gases exist in the atmosphere, and there are countless factors that corrode the iron base 11, it is natural that the end face 13
begins to corrode. In addition, as a characteristic of high frequency waves, they are transmitted through ceramics and resin molded objects, but reflected from metals, so at the inclined part of the waveguide upper plate 4 that connects to the heating chamber opening 7, the high frequency waves are reflected and follow the inclination. Electricity is supplied to the heating chamber 1 in this way. In addition, in the high frequency passage, the protruding parts and end faces have the property of being the strongest electric field parts, and even if confirmed in continuous heating experiments such as durability tests, the end face on the magnetron 3 side of the heating chamber opening 7 is Corrosion progresses rapidly due to strong corrosion. When used for a further long period of time, corrosion progresses from the end face portion 13 into the interior of the iron base 11 due to the steam generated during cooking and the heat generated when the upper heater is used. In the above, the magnetron 3 side end face 13 is in an eroded state and becomes very brittle. Therefore, when high-frequency heating is performed, a portion of the end face portion 13 is chipped and falls onto the surface of the mica plate 10 due to the impact when the door is opened and closed and the vibration when the food is taken in and out. When high frequency waves are oscillated in this state, sparks are generated between the end face portion 13 and the iron base material that has fallen onto the surface of the mica board 10, and the surface of the mica board 10 is destroyed by the spark heat. In addition, since food particles, oil, etc. adhere to the mica plate 10 during cooking, the adhering substances become carbonized due to the spark heat.
Intergranular sparks will occur, and the surface will be destroyed and crumbled, and the mica plate 10 will fall onto the food being cooked, or in severe cases, the mica plate 10 will burn, causing a fire in the heating chamber 1. I had a lot of flaws.

In addition, when heating the heating chamber, the upper plate 6 of the heating chamber reaches a very high temperature, which accelerates corrosion, and since the opening end surface is a cut surface by press working,
It is becoming easier to deform. Therefore, in the conventional configuration, the opening section is thermally deformed, and the opening area, which influences the cooking performance of the high-frequency heating device, changes, making it impossible to obtain the cooking distribution performance as designed.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and it is possible to prevent sparks from occurring on the mica plate even if the magnetron side end face of the lower waveguide plate or the upper plate of the heating chamber corrodes.
The purpose of the present invention is to provide a high-frequency heating device that prevents peeling and combustion of mica plates, and that can perform safe and accurate high-frequency power supply with stable cooking performance.

Structure of the Invention In order to achieve the above-mentioned object, the present invention bends the end face of the magnetron side of the high-frequency power feeding opening of the upper plate part forming the heating chamber at an acute angle or until it is in close contact with the end face of the upper plate part and the lower part of the waveguide. The end face of the plate part is configured so that it does not protrude onto the mica plate attached to the upper plate of the heating chamber, so that even if the end face of the metal plate corrodes, the iron base will not fall onto the mica plate. This prevents the generation of sparks.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below based on the drawings.

FIG. 3 is a sectional view of essential parts showing an embodiment of the present invention. In the figure, 4 is an upper waveguide plate constituting the waveguide, and 5 is a lower waveguide plate. 6 is the upper plate of the heating chamber; in high-frequency heating equipment with a heater heating function, it has the function of eliminating oil stains and odors in the heating chamber 1.
SC enamel surface treatment 14 has been applied. For this reason, the box-shaped waveguide cannot be spot-welded directly to the heating chamber upper plate 4, and the waveguide lower plate 5 is spot-welded in advance, and the unit is then welded to the opening where spot welding is possible. Three sides except for the magnetron 3 side around the part are spot welded, and the magnetron 3 side is tightly fixed with screws together with the mica plate 10 at intervals such that high frequency waves do not leak.

In the above configuration, the end face of the magnetron side of the high-frequency power feeding opening 7 of the heating chamber upper plate 6 is bent so as to be in close contact with each other by about 5 mm, and the opening end face of the lower waveguide plate 5 and the opening of the heating chamber upper plate 6 are bent. It is constructed in such a way that the end faces of the two parts touch each other. In addition, the heating chamber upper plate 6
The end face other than the magnetron side is configured to be located outside the side surface of the waveguide upper plate 4 or an extension of the sloped part so as not to be directly exposed to high frequency waves.

According to the above configuration, the end face of the heating chamber upper plate 6 other than the magnetron 3 side is not exposed to high frequency waves, so corrosion progresses extremely slowly, and even if corrosion occurs, the electric field strength is not strong enough to generate sparks, and the mica plate It does not lead to surface destruction. Also magnetron 3
The side end faces are bent so as to come into contact with the waveguide lower plate 5, so even if the end face of the heating chamber upper plate 6 or the end face of the waveguide lower plate 5 corrodes, the iron base of the end face will not be affected by the mica plate. It will not fall above 10.

Therefore, there is no possibility that sparks will be generated on the mica board 10 due to high frequency waves, and peeling or burning due to surface destruction of the mica board 10 can be prevented.

In addition, since the heating chamber upper plate 6 becomes very high temperature when heated by the heater, it is easily deformed by heat, but if the end face is bent tightly, the strength will increase due to work hardening of that part, and the heat will increase the strength. It is also becoming difficult to deform. Furthermore, when cutting a metal plate with a press, burrs always occur in the cutting direction, and if there is a burr in the strong electric field, sparks are generated immediately at the tip of the burr. By carefully and closely bending the side end surfaces, burrs will be removed by pressing and the opening dimensions of the heating chamber upper plate 6 will be accurate, allowing stable high-frequency power supply. As a result, the cooking distribution performance as designed can be obtained, and a high-frequency heating device with stable cooking performance can be obtained.

In addition, as an advantage in assembly, when fixing the waveguide upper plate 4 and the waveguide lower plate 5 that have been previously spot-welded into a unit to the heating chamber upper plate 6, the heating chamber upper plate 4 The tightly bent portion of the opening and the opening of the lower waveguide plate 5 are used for positioning, allowing quick and accurate assembly and improving productivity.

Furthermore, the areas around the openings of the heating chamber upper plate 6 and the waveguide lower plate 5 other than the magnetron 3 side are fixed by spot welding, so there is no high frequency leakage, and the opening end face on the magnetron 3 side has a small space. Since they are tangled, high frequencies in that space are attenuated, and high frequency leakage from the gap between the heating chamber upper plate 6 and the waveguide lower plate 5 is almost eliminated. As a result, a safe high-frequency heating device without high-frequency leakage can be obtained.

In addition, if the opening end face of the heating chamber upper plate 6 is bent closely all around the entire circumference as in another embodiment shown in FIG. Since the portion is sealed by the waveguide upper plate 4, the generation of sparks due to corrosion is almost completely eliminated, resulting in a safer and more reliable high-frequency heating device.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained with a simple structure in which one end surface of the heating chamber upper plate on the magnetron side is closely bent.

(1) Even if the upper plate of the heating chamber and the end face of the waveguide corrode, the iron base will not fall onto the mica plate, preventing the generation of sparks due to high frequency, and eliminating the surface damage of the mica plate.

(2) By increasing the strength of the end face of the opening, stable cooking performance can be obtained without worrying about thermal deformation.

(3) The close-contact bending part serves as a positioning tool, making assembly work easier and improving productivity.

(4) By aligning the end surfaces of the heating chamber upper plate and the waveguide lower plate, a safe high-frequency heating device without high-frequency leakage can be obtained.

(5) By using surface-treated steel plates such as aluminized steel plates for the heating chamber upper plate and the waveguide upper and lower plates, heat conduction is good and heat concentration is suppressed.
More advantageous for spark generation. Also,
Aluminized steel sheets also have excellent heat resistance, making them more advantageous against thermal deformation and further improving reliability.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a conventional high-frequency heating device, FIG. 2 is an enlarged sectional view of the same main part, FIG. 3 is a sectional view of a main part of an embodiment of a high-frequency heating device according to the present invention, The figure is a sectional view of a main part showing another embodiment. DESCRIPTION OF SYMBOLS 1... Heating chamber, 3... Magnetron, 4... Waveguide upper plate, 5... Waveguide lower plate, 6... Heating chamber upper plate, 9... Mica plate, 13... End surface part.

Claims (1)

[Claims] 1. A heating chamber in which food is placed and subjected to high-frequency heating, a high-frequency oscillator, and a box-shaped waveguide having an upper waveguide plate and a lower waveguide plate, At least the end face on the magnetron side of the high-frequency power feeding opening of the upper plate forming the heating chamber is bent at an acute angle or until they are in close contact, and the end face of the heating chamber upper plate and the end face of the waveguide lower plate are butted. heating device. 2. The high-frequency heating device according to claim 1, wherein the heating chamber upper plate, the waveguide upper plate, and the waveguide lower plate are made of surface-treated steel plates such as aluminized steel plates.