JPH0142570B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an improvement in the cooling structure and heating performance of a high-frequency heating device equipped with a heating device having a heating means such as an electric heater or a gas burner.

Structure of conventional example and its problems For example, in the conventional high-frequency heating device 1 with a heater as shown in FIGS. It is set in. At this time, when heating the object to be heated using high frequency waves, high frequency waves are generated by the high frequency oscillator 4, high voltage transformer 5, high voltage capacitor 6, etc., guided into the heating chamber 2 by the waveguide 7, and irradiated onto the object to be heated. Then heat. Further, a first fan motor 8 is provided to cool power supply components and structural components such as the high frequency oscillator 4 during high frequency heating. Next, when heating the object to be heated in an oven or on a grill, the electric heater 9 is energized to raise the temperature in the heating chamber 2 containing the object to be heated. Since the temperature in the heating chamber 2 becomes high, a second fan motor 11 is provided in order to suppress the temperature rise in the component storage space 10 to a low level.

FIG. 1 shows a cooling structure during high-frequency heating. In order to improve cooling efficiency, the first fan motor 8 and the second fan motor 11 are rotated simultaneously, and an air intake provided in the outer shell of the vessel is installed. Outside air is sucked in through the opening 12 for use in the high frequency oscillator 4, high voltage transformer 5, high voltage capacitor 6, and other particularly resin structural parts provided in the parts storage space 10 in the upper part of the heating chamber 2, as well as in the upper part of the door 3. After cooling the printed circuit board 14 mounted with various electronic components arranged behind the operation panel 13 provided therein, the structure is such that it is discharged to the outside of the vessel through the exhaust opening 15. In addition, in order to improve the cooling efficiency of the fan motor in the parts storage space 10, the propeller fan 1
A first air guide 18 having an orifice 17 with an appropriate clearance is provided on the outer periphery of the high frequency oscillator 4, and a second air guide 19 is provided to guide the air after cooling the high frequency oscillator 4 into the heating chamber 2. is provided in the heating chamber 1 provided on the upper plate 20 of the heating chamber 2.
is guided into the heating chamber 2 through the opening 21 of the heating chamber 2.
The air is exhausted from the opening 22 through the exhaust guide 23 to the outside of the vessel.

During heating by the electric heater 9, the inside of the component storage space 10 is cooled by the second fan motor 11, and at this time, the shaded area shown in FIG. 2 indicates the part where negative pressure is generated due to the rotation of the fan motor. On the other hand, since the temperature inside heating chamber 2 increases,
Since the hot air tries to flow out of the heating chamber 2 through the heating chamber first opening 21 provided in the upper plate 20 of the heating chamber 2, a large amount of hot air flows out as shown by the mark due to the synergistic effect described above. It has very poor thermal efficiency. In other words, even when the temperature inside the heating chamber 2 is raised, the temperature inside the heating chamber 2 does not rise easily because the heat is sucked by the second fan motor 11. The temperature in the vicinity of the first opening 21 of the heating chamber does not rise, resulting in poor temperature (heat) distribution and uneven heating.
This was a fatal flaw for a heating device, as it caused variations in temperature control relative to the set temperature within the heating device. In addition to hot air, water vapor generated by objects to be heated, especially pudding, etc., is also sucked in by the fan motor and sprayed onto the high voltage transformer 5, high voltage capacitor 6, high frequency oscillator 4, printed circuit board 14, etc., so that it hits the power supply components. If water vapor condenses and adheres to high-voltage parts in particular, insulation between the high-voltage part and the ground may not be ensured, resulting in high pressure being applied to the body, and in the case of the high-voltage transformer 5, it may cause serious problems such as smoke and ignition due to the rare shot of the secondary coil. This puts you in a dangerous situation. In addition, dew condensation may occur on the live parts of electronic components such as the microcomputer 24 and the IC 25, or on the patterns on the printed circuit board 14, resulting in malfunctions due to short-circuiting of the electronic circuits and runaway of the microcomputer 24, resulting in an extremely dangerous situation.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks.
It does not affect temperature control or temperature (heat) distribution, improves thermal efficiency, and keeps the temperature rise of high-voltage parts and electronic circuits low while preventing insulation deterioration due to water vapor and water vapor condensation and dangerous short-circuit conditions. The purpose is to have a simple structure.

Structure of the Invention In order to achieve the above object, the high-frequency heating device with a heating device of the present invention has a heating chamber for storing and heating the object to be heated, and has a heating means such as a high-frequency heating and an electric heater, a gas burner, etc. It is equipped with at least two fan motors installed in the parts storage space, and the air volume of the other fan motors is smaller than that of the first fan motor, which is driven only during high-frequency heating. A first air guide having an orifice with a clearance of , a third air guide is provided in the direction of the rotation axis of the axial fan on the suction side or the intake and discharge side of the fan motor, and in a direction that regulates the intake or exhaust direction, and is used for electric heaters, gas burners, etc. When performing heating using a fan motor, when forcibly cooling various parts in the parts storage space and the outer shell of the container, there is no effect on temperature control or temperature (heat) distribution within the heating chamber, and the heating Since the hot air and water vapor in the room are rapidly sucked in and blown onto the parts to be cooled, it not only prevents the cooling capacity from decreasing, but also causes the heating chamber 2 to rise in temperature very slowly, takes a long time to heat up, and wastes energy. It minimizes consumption and prevents dangerous conditions such as deterioration of insulation of high-voltage parts and short circuits due to water vapor and condensation of water vapor, malfunctions and runaway of microcomputers due to short circuits of electronic components and circuits. This has the effect of allowing the situation to be avoided.

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

4 and 5, when the object to be heated is stored in the heating chamber 2 and the electric heater 9 is energized, a high-voltage transformer 5 and a high-voltage capacitor are placed in the parts storage space 10 at the upper part of the heating chamber 2. The second fan motor 11 is mounted on the printed circuit board 14 and other electrical components such as 6 to cool various electronic components, especially resin structural components, etc. The second fan motor 11 is connected to the fan motor 8, which is driven only when performing high-frequency heating. Compared to this, the air volume is reduced. In other words, when using the same propeller fan 16, the rotation speed of the second fan motor 11 is lowered, and when the rotation speed is about the same, the propeller fan used for the second fan motor 11 is In other words, the drive capacity of the second fan motor 11 is reduced. Also, at this time, as shown in FIG. 6, a first air guide 18 having an orifice 17 with a size that provides a substantially constant clearance l on the outer circumference of the propeller fan 16 and an intake opening provided in the outer shell of the vessel body. 12, a third air guide 26 is provided in the rotation axis direction of the propeller fan 16 and in a direction regulating the intake direction. In addition, in FIG. 7, the fourth air guide 27 is arranged in the same direction as the third air guide between the first and second fan motors on the side from which the air is discharged by the fan motor than the first air guide 18. In particular, in this embodiment, when the high voltage transformer 5 and the first air guide 18 are close to each other, and the first air guide 18 and the third air guide 26 are made of ferromagnetic material. In order to prevent magnetic vibration due to leakage magnetic flux of the high voltage transformer 5 or to prevent magnetic vibration of the fourth air guide 27, the fourth air guide 27 is made of a non-magnetic material, so that the first air guide 18 The third air guide 26 or the fourth air guide 27 is configured to prevent magnetic vibration. Furthermore, a temperature switch 28 is provided to detect a temperature rise in or near the heating chamber 2 and drive the second fan motor 11.

The operation of the above configuration will be explained below.
First, in FIGS. 4 and 5, the electric heater 9
When heating the object to be heated by raising the temperature in the heating chamber 2 to a high temperature, the hot air and water vapor in the heating chamber 2 are transferred to the first heating chamber provided on the upper plate 20 of the heating chamber 2.
The air flows out from the opening 21 through the second air guide 19 into the component storage space 10 by natural convection. In addition, heat is radiated from each wall surface of the heating chamber 2, especially the upper plate 20, etc., and electrical components such as a high voltage transformer 5 and a high voltage capacitor 6 arranged in the component storage space 10 and various electronic components mounted on a printed circuit board 14. In order to cool other structural parts, especially those made of resin, forced cooling is performed by driving the second fan motor 11.
Compared to the first fan motor 8, which rotates only during high-frequency heating, the propeller fan 16 uses a propeller fan 16 of the same size and shape, so it rotates at a lower speed, so the air discharge pressure is lower. The negative pressure generated by driving also decreases as shown in the shaded area.
Therefore, forced suction of hot air and water vapor within the heating chamber 2 is reduced. Next, when a third air guide 26 is provided between the first air guide 18 and the intake opening 12 provided in the outer shell of the vessel as shown in FIG. The negative pressure generated by the drive is eliminated because the first air guide 18, the outer shell of the container body, and the third air guide 26 are isolated from the parts storage space 10 in a nearly sealed state. The pressure is generated as shown in the shaded area, and the pressure is generated in the first opening 2 of the heating chamber provided in the upper plate 20 of the heating chamber 2.
It is extremely rare for the hot air and water vapor in the heating chamber 2 to be forcibly drawn in by driving the first to second fan motors. In addition, the pressure generated by the high temperature inside the heating chamber 2 and the pressure generated by the drive of the second fan motor 11 in the component storage space 10 are expressed as the rotational speed of the second fan motor 11 and the By creating a balance in the design of the intake opening 12, exhaust opening 15, etc. provided in the outer shell of the body, it is possible to extremely reduce heat radiation due to natural convection from the portion where the amount of heat radiation is greatest. At this time, if the second fan motor 11 is made to have the same cooling capacity as, for example, the first fan motor 8 and the air flow is increased, the temperature during heating can be controlled by sending cooling air into the heating chamber 2. If the temperature (heat) distribution becomes very poor, or if the air flow rate is reduced while keeping the rotation speed of both at the same level, the high frequency oscillator 4 and high voltage transformer 5 during high frequency heating may
The cooling capacity of electrical parts such as the high frequency oscillator 4 in particular has a small heat capacity and a large amount of heat, so it is necessary to increase the capacity of the first fan motor 8 and set the discharge pressure particularly high than before. This could lead to a significant drop in high-frequency output due to overheating, a decrease in reliability, or a risk of burnout.

Next, in FIGS. 7, 8, and 9, a fourth air guide 27 is provided to rectify the flow of cooling air generated by the drive of the fan motor. The cooling air of the second fan motor 11 flows into the heating chamber 2 when the cooling capacity in the parts storage space 10 increases, with the aim of preventing interference when rotating simultaneously and increasing the cooling efficiency of each part. In order to eliminate the magnetic vibration of the first air guide 18 and the like due to the leakage magnetic flux of the high voltage transformer 5, it is made of a non-magnetic material and an elastic material that has a buffering effect. At this time, a temperature switch 28 is provided to detect a temperature rise in or near the heating chamber 2, but this operation is activated when the temperature in the heating chamber 2 rises to a certain level. It drives the second fan motor 11, and performs a delayed operation in which it continues to drive the second fan motor 11 as long as the temperature rise in or near the heating chamber 2 is high. When raising the temperature inside the heating chamber 2 to a higher temperature than room temperature, the second fan motor 11 rotates only when the heating chamber reaches a high temperature, depending on the operation setting of the temperature switch. The amount of heat released is extremely small and the temperature inside the heating chamber 2 can be raised quickly. Furthermore, even at the end of heating, it is possible to easily suppress the temperature rise in the component storage space 10 due to overshoot due to residual heat in the heating chamber 2. At this time again,
When attempting to perform a delayed operation of the second fan motor 11 during heating by high-frequency heating and electric heater, if there is no third air guide 26 or fourth air guide, the second fan motor 11 is operated as described above in FIG. The temperature rise due to the suction of hot air and water vapor in the heating chamber 2 by the drive of the motor 11 and the short circuit state of the cooling air in the parts storage space 10 not only suppress the temperature rise in the parts storage space 10 but also reduce the temperature rise due to the suction of hot air and water vapor in the heating chamber 2. It is clear that the harmful effects of water vapor condensation increase.

In this way, according to this embodiment, when the second fan motor 11 rotates and cools the parts storage space 10, it forcibly sucks the hot air and water vapor inside the heating chamber 2, thereby reducing the temperature inside the refrigerator when heated by the electric heater. Not only does it take extra time for the temperature to rise, and despite forced cooling, it is not possible to keep the temperature rise inside the component storage space 10 low, and the temperature is not as high as the set temperature, which is an important property of the original heating device. It is a cooling configuration that does not adversely affect control and temperature (heat) distribution, and ensures insulation resistance between the high-voltage parts such as the high-frequency oscillator 4, high-voltage transformer 5, and high-voltage capacitor 6, and the high voltage due to condensation of water vapor and water vapor. Smoke and ignition due to secondary coil rear shot of transformer 5 and microcomputer 24
It is possible to avoid malfunctions due to short-circuit conditions such as live parts of electronic components such as the IC 25 and patterns on the printed circuit board 14, and extremely dangerous situations due to runaway of the microcomputer 24, and also to drive the second fan motor 11. The original purpose of this is to greatly improve the cooling performance of the parts storage space 10 and the outer shell of the container, and also to quickly raise the temperature in the heating chamber 2, or to reduce the leakage magnetic flux of the high voltage transformer 5. It has the effect of preventing magnetic vibration.

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

(1) Forced cooling makes it possible to keep the temperature rise in the parts storage space and the outer shell of the container to a low level without requiring additional time for the temperature in the heating chamber to rise. By downgrading the insulation type and heat resistance of parts, electronic parts, and other resin-manufactured parts in particular, the cost can be significantly reduced, making it possible to provide the products to users at low prices. In addition, since the temperature rise in the outer shell of the container is low, the structure is such that even if the user touches it, there is no risk of burns or a feeling of anxiety.

(2) Through forced cooling, cooling air flows into the heating chamber, and conversely, hot air is sucked in by the negative pressure generated by the drive of the fan motor, thereby achieving temperature control and temperature (heat) distribution, which are important performances of heating equipment. This configuration does not adversely affect the cooling performance or significantly reduce the cooling performance. In addition, it is configured to avoid dangers caused by deterioration of insulation performance of high-voltage parts due to water vapor and condensation of water vapor, and to prevent malfunctions and runaway of microcomputers due to short circuits of electronic parts and printed circuit boards.

(3) It is possible to prevent magnetic vibration due to leakage magnetic flux of the high voltage transformer, and to greatly improve the cooling capacity even during high frequency heating. This improvement will lead to significant reductions in size, weight, and cost.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing the cooling structure during high-frequency heating of a conventional high-frequency heating device with a heating device, Figure 2 is a cross-sectional view showing the cooling structure during heating by the electric heater in Figure 1, and Figure 3 is the 2 is a side sectional view of FIG. 2, FIG. 4 is a sectional view showing the generation of negative pressure in the cooling structure during heating by an electric heater of a high-frequency heating device with heating device, which is an embodiment of the present invention, and FIG. 5 is a sectional view of the side view of FIG. FIG. 4 is a side cross-sectional view, and FIG. 6 is a cross-sectional view showing another embodiment of the present invention, which has a third air guide. FIG. 7 is a sectional view of another embodiment of the present invention, which has a fourth air guide and a heating chamber or a temperature detection means in the vicinity of the heating chamber; FIG. 8 is a sectional view taken from the side of FIG. FIG. 9 is a sectional view showing the flow of cooling air during high-frequency heating in FIG. 7. 2... Heating chamber, 4... High frequency oscillator, 9... Electric heater, 5... High voltage transformer, 6... High voltage capacitor, 8... First fan motor, 11...
...another fan motor (second fan motor),
16... Axial flow fan (propeller fan), 17...
... Orifice, 18 ... First air guide, 19
... second air guide, 26 ... third air guide, 27 ... fourth air guide, 28 ... means for detecting temperature (temperature switch).

Claims (1)

[Claims] 1. A heating chamber that stores and heats the object to be heated in a part of the container, heating means such as an electric heater or gas burner, high-frequency oscillation means such as a high-frequency oscillator, high-voltage transformer, high-voltage capacitor, and high-voltage diode, and the above-mentioned high-frequency At least two or more fan motors are provided to cool the oscillation means and structural parts inside the vessel, and the fan motors are driven simultaneously during high-frequency heating, and when heating with an electric heater, gas burner, etc., a magnetron cooling installed on one wall of the heating chamber is provided. In a configuration in which only other fan motors not facing the ventilation holes are driven, the first fan motor is driven only during high-frequency heating.
Other fan motors than the fan motor of
High frequency heating device with heating device with reduced air volume.