JPS6032286A - High frequency heater - 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 the Invention The present invention relates to a cooling structure for an operation panel of a high-frequency heating device equipped with a heating device for increasing the temperature of a heating chamber.

Conventional configurations and their problems In recent years, as electronic control circuits have been increasingly applied to home appliances,
Application has also begun to high-frequency heating devices (hereinafter abbreviated as high-frequency heating devices) equipped with a heating device that raises the temperature of a heating chamber. When the high-frequency heating device performs cooking using an electric heating device such as a sheathed heater, the heating chamber reaches a high temperature, which causes the temperature of all parts inside the main body to rise. In general, the ambient temperature limit for semiconductor devices used in electronic circuits is 76
It is °C. Therefore, in order to apply an electronic circuit to a high-frequency heating device, the temperature on which the parts constituting the electronic circuit are mounted (hereinafter referred to as a printed circuit board) must be kept at 75° C. or lower, as described above. Conventionally, in order to cool the printed circuit board below the temperature limit, the fan that cools the high frequency generator during high frequency heating is also used when heating the electric heating device to cool the printed circuit board. However, this configuration causes the following problem.

First, during high-frequency heating, it is necessary to prevent the glass of the door's see-through window in the heating chamber from fogging up, and to ventilate the heating chamber by introducing cooling air from the high-frequency generator into the heating chamber. However, when heating an electric heating device, the heating chamber must be heated to a high temperature, so cooling air cannot be introduced into the heating chamber. Therefore, it is necessary to switch the exhaust route of the cooling air using the respective heating means during high-frequency heating and when heating the electric heating device. Is required.

Conventionally, a shutter was installed in the duct that introduced the cooling air from the high-frequency generator into the heating chamber, and the shutter was driven by a servo motor or solenoid to switch the exhaust path. The second problem is that when the operation panel is cooled, the outside surface of the heating chamber is also cooled, so in order to improve efficiency when heating the electric heating device, it is necessary to install insulation around the entire circumference of the heating chamber. Had to get better insulation. As described above, relying on a cooling fan to cool the operation panel when it is heated by the electric heating device has the disadvantage of resulting in a very complicated and expensive configuration.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and an object thereof is to provide a high-frequency heating device that has a simple configuration, is inexpensive, and has high reliability.

Structure of the Invention In order to achieve the above-mentioned object, the high-frequency heating device of the present invention has a metal fitting for fixing the operation panel on the front side of the main body, which has a facing surface facing the side surface of the heating chamber, and furthermore, this can be used as a plurality of printed circuit boards to be mounted on the operation panel. By arranging the printed circuit board that could not be attached on this opposing surface, there is an effect that the printed circuit board itself can be used to efficiently cool the circuit board.

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

FIG. 1 is a diagram showing the appearance of the high-frequency heating device, with the door open. In FIG. 1, 1 is a main body, and 2 is a door that can be opened and closed. 3 is a heating chamber that houses the object to be heated. A mounting table 4 according to the same method is disposed inside the bottom surface 3d of the heating chamber 3. Reference numeral 6 denotes an operation panel, which includes a display section 6 and a keyboard 7. Further, a heating device 8 composed of a 7-Z heater or the like is provided in the heating chamber 3 to raise the temperature inside the heating chamber 3.

FIG. 2 is a rear perspective view showing the internal structure.

In FIG. 2, reference numeral 9 denotes a high frequency generator that supplies high frequency waves into the heating chamber 3 via a waveguide 10.

11 is a high-voltage transformer, and 12 is a cooling fan that is rotated during high-frequency heating. Reference numeral 13 denotes a fixing plate for fixing the operation panel 5, and has an opposing plate 14 facing the side surface of the heating chamber 3. 15 and 16 are printed circuit boards, and the printed circuit board 15 is fixed to the operation panel 6. printed circuit board 16
Place the opposing plate 14 so that the parts on the board are on the side of the main body 1.
to be placed. Whether the opposing surface 14 is integrated with the fixing plate 13 or separate from it may be selected as appropriate. An opening 17 is provided on the bottom of the main body 1, which serves as an exhaust port for the air cooled by the cooling fan 12 to the high-frequency generator 9, high-voltage transformer 11, etc. during high-frequency heating, and serves as an intake port for guiding cold outside air into the main body during electric heating. .

FIG. 3 is a rear sectional view showing the air intake and exhaust state in the main body 1 during electrothermal heating. In FIG. 3, black arrows 18 indicate the flow of air heated to a high temperature by the heating device 8 disposed within the heating chamber 3. White arrow 19 indicates opening 17 provided on the bottom of main body 1
Shows the flow of cold outside air entering through. 2o is an exhaust port provided on the top surface of the main body 1.

The operation of the above configuration will be explained below.

When the heating device 8 in the heating chamber 3 is energized, the temperature of the air outside the heating chamber 3 rises and becomes high temperature.
thermally shields the hot air 18, so that the components of the printed circuit board 15, 16 are not affected by the heat. Also, the cold outside air 19 is discharged to the outside of the main body 1 through the exhaust port 2o while cooling the printed circuit board 16i and 160 components.

As described above, according to this embodiment, even when cooking is performed using an electric heating device, the parts of the printed circuit board can be protected by the heat shield made up of the opposing surface 14 provided on the fixed plate 13 and the printed circuit board 16 provided on the opposing plate 14. It has the effect of being able to cool down.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

1 The opposing plate provided on the fixed plate that fixes the operation panel on the front of the main unit and the printed circuit board provided on this opposing plate have the effect of a heat insulating board that shields the hot air from the heat, making it similar to the conventional cooling fan. Unlike the expensive and complicated structure of the conventional method, the structure is simple, inexpensive, and economical because the printed circuit board itself performs the process.

2. The more you try to eliminate uneven heating that tends to occur during cooking, the more complicated the heating mode becomes, resulting in more complicated circuits and larger printed circuit boards. However, there is a limit to the number of printed circuit boards that can be attached to the operation panel, so multiple printed circuit boards are required, and it is difficult to secure space for printed circuit boards that cannot be attached to the operation/S panel. However, by attaching it to the opposing plate, the mounting space for the printed circuit board can be secured, which is effective in saving space.

3. Connecting the lead wires to the printed circuit board attached to the operation panel is done from the rear, making it difficult to see the connection points and making the work very difficult. The printed circuit board 16 attached to the opposing plate of the present invention improves work efficiency because the parts can be worked while looking at the connection points on the side of the main body.The high-frequency heating device is not caused by poor contact due to incomplete insertion. This eliminates malfunctions and improves quality.

[Brief explanation of the drawing]

Fig. 1 is an external view of a high-frequency heating device according to an embodiment of the present invention with the door open, Fig. 2 is a rear perspective view showing the internal structure of the high-frequency heating device, and Fig. 3 is a perspective view of the same device. FIG. 3 is a cross-sectional view showing the flow of hot air and cold outside air as seen from the rear. 1... Main unit, 2... Door, 3... Heating chamber, 5... Operation panel, 7... Keyboard, 9
...-High frequency generator, 13...Fixing plate, 14
...Opposite plate, 16°16...Printed circuit board, 1 end...-opening. Name of agent: Patent attorney Toshio Nakao and one other person Figure 2 Figure 3

Claims (1)

[Claims] A high frequency generator that supplies high frequency waves to a heating chamber, a heating device that increases the temperature of the heating chamber, an operation panel on the front of the main body, and an output signal from the operation section of this operation panel to control the operation of the high frequency heating device. A plurality of electronic circuit boards are provided, an operation panel fixing plate is disposed behind the operation panel, the fixing plate is provided with a facing plate facing a side surface of the heating chamber, and the electronic circuit board is disposed on the facing plate. The high frequency heating device is configured such that heat from the heating chamber is shielded by an opposing plate provided on the fixed plate and the electronic circuit board provided on the opposing plate.