JP2006308114A - High frequency heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve difference in temperature distributions between front and rear heaters in a heating chamber. <P>SOLUTION: This high frequency heating device comprises a rotary antenna 8, a front heater 12a, a relay 16a, a rear heater 12b and a relay 16b, and duty factor of the front heater and the rear heater are made variable, so that the duty factor of the front heater of weaker temperature distribution is increased to be higher than that of the rear heater, and heat quantity of a front portion can be increased, thus the difference in distributions between the front and rear heaters can be improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a structure of a bottom heater of a microwave oven in which a microwave oven without a turntable and a heater heating device are integrated.

Conventionally, as a bottom heater of this type of microwave oven, a circular sheathed heater or a heater in which a heater wire is wound around a mica laminate is arranged on the bottom surface outside the heating chamber (see, for example, Patent Document 1). ). In some cases, a ring heater is disposed in the heating chamber on the bottom surface (see, for example, Patent Document 2).
JP 2002-213753 A JP 2002-286229 A

  However, in the conventional configuration, considering the heater heating state in an actual microwave oven, there is a door on the front surface of the heating chamber, and the front surface of the door is generally made of transparent heat-resistant glass so that the state of the heating chamber can be seen. Is. And the heat insulation of a heating chamber is ensured by covering the wall surface of another heating chamber with a metal via the wall surface of a heating chamber, an air layer, and a heat insulating material.

  Moreover, it is common to perform oven cooking after preheating. At the end of this preheating, the door is opened and the food to be heated is placed in the heating chamber, so the atmospheric temperature on the front side of the heating chamber is affected by the air temperature of the room lower than the heating chamber, In particular, the structure tends to be lower than the rear surface of the heating chamber.

  FIG. 6 is a diagram showing the flow of air for supply / exhaust of the heating chamber. The magnetron 22 is cooled by the outside air supplied by the cooling fan 21, and this air is heated from the intake port 24 provided on the side wall of the heating chamber 23. After entering the chamber 23, it is exhausted out of the apparatus through an exhaust port 25 provided on the rear surface of the heating chamber. As described above, the microwave oven generally has a configuration in which the radio wave heating and the heater heating are integrated, so that the steam generated from the food in the heating chamber is exhausted outside the heating chamber by using the cooling air of the high-frequency magnetron. The configuration is common. In such an air supply / exhaust configuration, when the radio wave is heated, the amount of heat generated by the magnetron 22 is large, and thus the amount of cooling air is large. However, since the magnetron 22 is not used when heating the heater, the airflow into the heating chamber 23 is to reduce the number of rotations of the magnetron 22 and the cooling fan 21 for cooling the power supply parts to stabilize the internal temperature. To a minimum. However, since a small amount of wind flows from the front of the heating chamber to the rear exhaust port, the temperature at the rear tends to be higher than that at the front, that is, the food tends to be baked better at the rear.

  In the conventional configuration, only one heater is used as the circular heater 26 or the planar heater (not shown) shown in FIG. 6, and the heater ON / OFF control is generally used when controlling the temperature of the heating chamber. It is. Because this heater control is for ON / OFF control of one heater, the temperature distribution in the heating chamber is easily affected by the shape of the heater and the temperature distribution in the heating chamber (the front is weak and the back is strong). There is a problem that the difference in distribution is conspicuous in planar cooking such as cookies and madeleine.

  The present invention solves the above-described conventional problems, and in order to eliminate the difference between before and after the temperature distribution of the heating chamber, the conventional heater is replaced with a round or flat heater, and the tube heater is replaced with a radio wave agitator at the bottom of the heating chamber. As a circuit configuration that is provided on both sides of the rotating antenna for use and controls the heater circuit independently, it is turned on and off according to the form of the heated food, eliminating the difference before and after the heater heating distribution and excellent in uniform heating An object of the present invention is to provide a heating device.

  In order to solve the above-described conventional problems, the high-frequency heating device of the present invention is configured such that heaters installed on the bottom surface of the heating chamber are arranged before and after the bottom surface of the heating chamber with the rotating antenna for radio wave stirring as the center. Each heater has an independent control circuit configuration, that is, a circuit configuration in which relays are provided in the front and rear heater circuits so that only the front heater is ON, only the rear heater is ON, or ON / OFF simultaneously.

  As a result, the difference in the heating distribution of the bottom heater due to the structural reason described above, if the front is weaker than the rear, shorten the ON time of the rear heater, or turn it OFF to reduce the heater heating amount. By controlling the heater to remain ON, an attempt is made to eliminate the difference between before and after heating the heater. The ON / OFF control of the front and rear heaters is possible by determining the ON / OFF ratio according to the type of cooked food that has been confirmed in advance and performing a program, and selecting the cooked key provided in the operation unit. .

  Moreover, since the bottom heater of the heating apparatus of the present invention employs a tubular heater, the temperature rise characteristic is faster than that of a conventional sheathed heater.

  The heating apparatus of the present invention can provide uniform heating of food heaters by using an independent heater.

  The first invention includes a heating chamber, a magnetron, a receiving tray for partitioning the heating chamber and the bottom of the heating chamber, a waveguide for propagating radio waves from the magnetron to the bottom of the heating chamber, and heating the propagated radio waves to the heating chamber. A feeding port for irradiating the chamber, a rotating antenna for stirring the radio wave, and a heater for heating, the heater for heating being arranged on the front side and the rear side of the bottom surface of the heating chamber with the rotating antenna as a center, It is configured to be able to turn on and off independently. Heating unevenness before and after heater heating is strengthened for heaters where heating is insufficient (longer ON time), and heaters on weaker sides are weakened. This can be solved by shortening the ON time. A microwave oven without uneven heating of the heater can be provided.

  The second invention includes a heating chamber, a magnetron, a tray for partitioning the heating chamber and the bottom surface of the heating chamber, a waveguide for propagating radio waves from the magnetron to the bottom surface of the heating chamber, and heating the propagated radio waves to the heating chamber. It is equipped with a power supply port for irradiating the chamber, a rotating antenna for agitation of radio waves, and a heater for heating. The heater for heating is arranged in front of, behind, left and right of the bottom of the heating chamber, and is turned ON / OFF respectively. In addition to the effects of the first invention, uneven heating on the left and right can be eliminated.

  In the third invention, the heater for heating according to the first or second invention is a tubular heater covered with a metallic cover, and the temperature rise characteristic can be accelerated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows the appearance of the heating chamber in the first embodiment of the present invention.

  In FIG. 1, the door 1 is attached to face the heating chamber 2 and is opened and closed when food is taken in and out of the heating chamber. Heating is performed by the operation unit 3. The outer shell 4 covers the heating chamber and other electrical components.

  FIG. 2 is a front sectional view of the first embodiment of the present invention. The radio wave oscillated from the magnetron 5 is supplied from the opening 7 to the heating chamber 2 through the waveguide 6. The radio wave is agitated by the rotating antenna 8 to make the radio wave uniform. The rotating antenna 8 is rotated by an antenna motor 9. The heating chamber 2 is partitioned by a tray 10 provided on the bottom surface of the heating chamber 2 to form a heating chamber bottom surface portion 11. The heating antenna bottom surface portion 11 is provided with the rotating antenna 8 and the heater 12 for heating. An upper heater 13 is provided in the upper part of the heating chamber. The cooling fan 14 cools the magnetron 5 and other electrical components (not shown).

  FIG. 3 is a plan sectional view according to the first embodiment of the present invention, and FIG. 4 is a side sectional view. As shown in FIGS. 3 and 4, as the heater 12 for heating, a front heater 12 a and a heater 12 b are provided to face the rotating antenna 8. 15a and 15b are metal shielding plates that cover the heater, and protect the tube heater from radio waves. The heat distribution of the heater can be improved by making a hole in the shielding plate.

  As shown in the block diagram of FIG. 5, a relay 16a is connected to the front heater 12a, and a relay 16b is connected to the heater 12b. A relay 17 is connected to the upper heater 13. The magnetron 5 is supplied with power by an inverter power supply 20. The thermistor 18 is for detecting the temperature inside the heating chamber. The relays 16 a and 16 b, the inverter power supply 20, the cooling fan 14, and the antenna motor 9 are configured to be controlled by the control unit 19.

  About the heating apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, at the time of heating the heater, the relay connected to each of the upper heater 13 and the heaters 12a and 12b is turned on and energized to increase the temperature in the heating chamber.

  When the ambient temperature of the thermistor 18 that detects the temperature in the heating chamber reaches a set temperature, when the heaters 12a, 12b, and 13 are stopped and become lower than the pre-programmed temperature, this time, each relay sends an ON signal from the microcomputer. Is output and the heater is turned on. By repeating this operation, the temperature in the heating chamber is controlled to a set temperature. The heater ON / 0FF time at the time of temperature control is programmed by determining in advance a certain period of time, for example, a time for turning on and turning off for 30 seconds.

  For example, when the temperature is set to 200 ° C., the temperature of the thermistor 18 exceeds 200 ° C. if the upper heater is programmed for 20 seconds ON, 10 seconds OFF, the lower heater is programmed for 15 seconds ON, and 15 seconds OFF. In the case of the upper heater, the time during which the temperature of the thermistor 18 exceeds 200 ° C. in the ON time 20 seconds is turned OFF. When the temperature of the thermistor 18 becomes lower than 200 ° C., the upper heater is turned on for a low period of 20 seconds.

  The operation of the lower heater is also controlled in the same manner. In this embodiment, the lower heater is turned off when the temperature of the thermistor 18 exceeds the set temperature. It is possible to set ON for 20 seconds and ON time for the rear heater to 15 seconds. Therefore, the ratio of energizing the front heater can be higher than that of the rear heater. As a result, the amount of heat in the front heater portion can be made higher than that in the rear heater.

  The ratio of energizing the heaters before and after this can be determined in advance by experiments and determining the optimum one depending on the food material and the heating temperature. For example, thin cookies such as cookies are easily affected by the heat distribution in the cabinet, so select a control program that increases the energization ratio on the front side and select this program with the cookies provided on the operation unit. The temperature distribution in the chamber can be made uniform and uniform baking can be performed.

  Further, by providing four front and rear heaters in the present embodiment independently on the front and rear and right and left to change the energization rate of each heater, a more uniform temperature distribution can be obtained.

  As described above, since the high-frequency heating device according to the present invention can suppress heating unevenness and obtain a uniform temperature distribution, it can also be applied to various uses of heating cookers.

External view of high-frequency heating apparatus in Embodiment 1 of the present invention Front sectional view of the high-frequency heating device according to Embodiment 1 of the present invention. Plan sectional drawing of the high frequency heating apparatus in Embodiment 1 of this invention Side surface sectional drawing of the high frequency heating apparatus in Embodiment 1 of this invention Block diagram of the high-frequency heating device in Embodiment 1 of the present invention Schematic which shows the supply / exhaust in the store | warehouse | chamber of the high frequency heating apparatus in Embodiment 1 of this invention.

Explanation of symbols

2 Heating chamber 5 Magnetron 6 Waveguide 7 Feed port 8 Rotating antenna 10 Sauce pan 11 Heating chamber bottom surface portion 12a Pre-heater (heater for heating)
12b Heater (heater for heating)

Claims (3)

A heating chamber, a magnetron, a tray for partitioning the heating chamber and the bottom surface of the heating chamber, a waveguide for propagating radio waves from the magnetron to the bottom surface of the heating chamber, and a power supply port for irradiating the heating chamber with the propagated radio waves And a rotating antenna for electric wave agitation and a heater for heating, the heater for heating being arranged on the front side and the rear side of the bottom surface of the heating chamber with the rotating antenna as a center, A high-frequency heating device that can be turned off. A heating chamber, a magnetron, a tray for partitioning the heating chamber and the bottom surface of the heating chamber, a waveguide for propagating radio waves from the magnetron to the bottom surface of the heating chamber, and a power supply port for irradiating the heating chamber with the propagated radio waves And a rotating antenna for electric wave agitation and a heater for heating, and the heater for heating is arranged in front, rear, left and right of the bottom of the heating chamber, and can be turned on and off independently. High frequency heating device. The high frequency heating apparatus according to claim 1 or 2, wherein the heating heater is a tubular heater and is covered with a metallic cover.

Images