JP2719413B2 - High frequency heating equipment - Google Patents

Description

The present invention relates to a high frequency heating device such as a microwave oven.

(B) Prior art In a general microwave oven disclosed in Japanese Utility Model Publication No. 55-50504, a high-frequency generator driven while being cooled by a cooling device includes a high-voltage transformer and a high-voltage capacitor having predetermined rated values. The high-voltage power is supplied through such as to drive. In this case, even if the high-frequency generator is continuously driven to perform heating at the maximum high-frequency output for a long time, the high-frequency generator does not reach an abnormally high temperature because it is cooled by the cooling device.

By the way, as the maximum high-frequency output increases, the performance of the microwave oven improves and the heating time can be shortened.
In order to increase the maximum high-frequency output in this way, for example, it is preferable to increase the rated value of the high-voltage capacitor. In this case, if the maximum high-frequency output is increased in this way,
Since the amount of heat generated by the high-frequency generator and the like increases, the cooling capacity of the cooling device also needs to be improved.

However, in order to increase the cooling capacity, the size of the cooling device is increased, and the cost of the microwave oven is increased.

(C) Problems to be Solved by the Invention The present invention aims to provide a high-frequency heating device capable of shortening the heating time without increasing the cost.

(D) Means for Solving the Problems A high-frequency heating apparatus according to the present invention supplies a high-frequency wave into the heating chamber while being cooled by the heating chamber containing the object to be heated, a cooling apparatus, and the cooling apparatus. A high-frequency generator that becomes abnormally high when continuously driven for more than a predetermined time; a drive mode setting unit; a time setting unit that sets a time associated with a drive mode set by the drive mode setting unit; When the time set by the time setting means exceeds the predetermined time when the continuous driving of the high frequency generator is set by the above, the prohibition means prohibits the continuous driving.

(E) Function When the high frequency generator is continuously driven for more than a predetermined time, the high temperature is abnormally high even though the high frequency generator is cooled by the cooling device. This is because the rated value of the high-voltage capacitor has been increased. Thus, when the high-frequency generator is continuously driven, the maximum high-frequency output is increased, and the heating time is shortened.

Furthermore, when the maximum high-frequency output is increased as described above,
The calorific value of the high-frequency generator increases, and the cooling device should be originally enlarged to improve the cooling performance of the cooling device, but the cooling performance of the cooling device has not been improved,
Therefore, if the high-frequency generator is continuously driven for more than a predetermined time, it will have an abnormally high temperature. However, when the continuous driving mode is set, if the set time exceeds the predetermined time, the continuous driving is prohibited, and the cooling device is not enlarged to improve the cooling performance of the cooling device. In both cases, the high-frequency generator can be prevented from becoming abnormally high temperature, and the cost of the microwave oven does not increase.

(F) Embodiment FIGS. 1 and 2 show the structure of a microwave oven according to an embodiment of the present invention.
And an electrical equipment room 4 are formed.
In the electric equipment room 4, a high-frequency generator for supplying high-frequency waves for heating the food 2 into the heating room 3, that is, a magnetron 5, a high-voltage transformer 6 and a high-voltage capacitor for applying high-voltage power to the magnetron And a cooling device 8 for cooling the magnetron 5, the high-voltage transformer 6, and the high-voltage condenser 7. On the front surface of the microwave oven main body 1, a door 9 for opening and closing the front opening of the heating chamber 3, a display device 10, and a keyboard 11 are provided. Referring to FIG. 3, the display 10 has a numeral display section 12 for displaying the heating time and a drive mode display section 13 for displaying the drive mode of the magnetron 5. The keyboard 11 sets the high frequency output, rapid heating key 14, 650W
Key 15,450W key 16,300W key 17,150W key 18,80W key 19 and number keys 0,9,2 for setting the heating time
, And a start key 21 for starting heating.
The rapid heating key 14, the 650W key 15, the 450W key 16, the 300W key 17, the 150W key 18, and the 80W key 19 are drive mode setting means, and the numeric keys 20, 20, ... are time setting means.

FIG. 4 shows the circuit of the microwave oven, and a control unit 22 including a microcomputer is provided for controlling the microwave oven.
Based on the setting information from 11, the display drive control of the display 10 is performed, and the ON / OFF control of the first and second switches 23 and 24 is performed. When the first switch 23 is turned on,
Commercial power is applied to the high-voltage transformer 6 via a power fuse 25 and a door switch 26 which is turned on when the door 9 is closed. Is applied, and a high frequency is supplied from the magnetron 5 into the heating chamber 3 to heat the food 2. When the second switch 24 is turned on, the power fuse 25 and the door switch
The commercial power supply is applied to the cooling device 8 via 26, the cooling device 8 is driven, and the magnetron 5, the high voltage transformer 6, and the high voltage capacitor 7 are cooled.

The operation of the microwave oven is controlled by the control unit.
FIG. 5 showing the flow of the operation program incorporated in 22.
This will be described with reference to FIGS. 6 and 7.

First, as a first step, the food 2 is heated for 5 minutes in a driving mode of a high-frequency output of 450 W, and then, as a second step, when the food 2 is heated for 15 minutes in a driving mode of a high-frequency output of 300 W, the keyboard 11 is used. , And key operation.

In this case, when the 450W key 16 is first operated, the routine of the operation program shown in FIG. 5 is executed. Such a routine consists of 450W key 16, 650W key 15, 300W key 1
It is executed even if the 7, 150W key 18 and 80W key 19 are operated first.

Then, based on the operation of the 450W key 16, first, a high-frequency output 450W corresponding to the key 16 is set in step A1 of FIG. Next, steps A2, A3, and A4 are cyclically executed. In step A2, press the numeric key 2 on the keyboard 11
The heating time by the operation of 0, 20,... Is set. In step A3, it is determined whether or not a key operation for setting a high-frequency output has been performed. In step A4, it is determined whether the start key 21 has been operated. Therefore, in such a circular execution, 5, 0, 0 and the numeric keys 20,
When 20 ... is operated, the above-mentioned A2 step
A heating time of 5 minutes for 0 W is set. Then 300W key
When 17 is operated, it returns from A3 step to A1 step,
Further high-frequency output 300W is set, then A2, A3, A4 again
The steps are performed cyclically. Followed by 1,5,0,0
Are operated, the heating time for the high-frequency output 300W is set to 15 minutes in the A2 step.

When the start key 21 is operated to execute heating after such a key operation, the above-described circulation execution ends at step A4, and thereafter, an operation program routine shown in FIG. 7 is executed. In this routine, first, at step C1, the second switch 24 is turned on to start driving the cooling device 8, and the magnetron 5 and the like are cooled. In the subsequent C2 step, a countdown of 5 minutes of the heating time for the first high-frequency output of 450 W is started. Then C3
At step, it is determined whether or not the heating time has become 0 based on the countdown. If it is not 0 in this case, then the C4 step is executed and the driving form is 650W
It is determined whether or not: In this case, the driving form is
Since it is 450W (650W or less), the C5 step is executed thereafter. In this step, as shown in FIG. 8 c, the first switch 23
Is turned on for 18.4 seconds at a cycle of 30 seconds, and based on this, the magnetron 5 is intermittently driven, and heating with a high-frequency output of 450 W is started. In this C5 step, if the high-frequency output of the current driving mode is 650 W, the first switch 23 is turned on for 26 seconds at a cycle of 30 seconds as shown in FIG. In each case Figure 8d,
Turn on for 12.8 seconds, 6.8 seconds, and 4.4 seconds as in e and f. And
Steps C2 to C5 are cyclically executed.

Eventually, when the heating time related to the high-frequency output becomes zero, the circulation execution ends at step C3, and step C6 is executed, and it is determined whether the high-frequency output is continuously set. In this case, the high-frequency output of 300 W is continuously set, and then the steps C2 to C5 are circulated again. In the recirculation execution, a countdown of 15 minutes of the heating time for the high-frequency output 300W is started in the C2 step. In step C5, the first switch 23 is turned on for 12.8 seconds in a 30-second cycle as shown in FIG. 8d according to the high-frequency output of 300 W which is the current drive mode.
Based on this, the magnetron 5 is intermittently driven, and heating with a high-frequency output of 300 W is started. Then, when the heating time related to the high-frequency output 300W becomes 0, the C6 step is executed again, but thereafter, there is no setting of the high-frequency output,
Therefore, the C7 step is then executed. In this step, the on / off control of the first switch 23 is stopped to end the heating, and the second switch 24 is turned off to stop the cooling of the magnetron 5 and the like.

Thus, as a first step, the food 2 is heated for 5 minutes in the driving mode with the high-frequency output of 450 W, and subsequently, in the second step, heating the food 2 for 15 minutes in the driving mode with the high-frequency output of 300 W is completed. It is. Then, during the heating, the cooling device 8 is driven to cool the magnetron 5 and the like, and the magnetron 5 and the like do not reach an abnormally high temperature.

By the way, when performing rapid heating for 3 minutes, use the keyboard
At 11, And key operation.

In this case, when the rapid heating key 14 is operated first, the operation program routine shown in FIG. 6 is executed. Then, first, in step B1, a maximum high-frequency output 800W corresponding to the key 14 is set. In the subsequent B2 step, it is determined whether another high-frequency output is set before the maximum high-frequency output 800W. In this case, there is no other setting of the high frequency output, and then the steps B3 and B4 are cyclically executed. In the B3 step, the heating time by operating the numeric keys 20, 20,... Is set. In step B4, it is determined whether start key 21 has been operated. Therefore, in such a cyclic execution, 3,0,0 and the numeric keys 20,20,
… Is operated, the maximum high frequency output is 80 in the above B3 step.
A heating time of 3 minutes for 0 W is set.

When the start key 21 is operated to perform heating after such a key operation, the above-described circulation execution ends at step B4, and then step B5 is executed. In this step,
It is determined whether the heating time set as described above is equal to or less than the predetermined time of 5 minutes.

Then, in this case, a determination is made for five minutes or less, and thereafter, a routine as shown in FIG. 7 is executed, and C1 is executed as described above.
After the drive of the cooling device 8 is started in the step, C2, C
3. Steps of C4 are executed. At this time, in the C4 step, the high frequency output is the maximum 800 W and 650 W
Since it is not the following, the C8 step is executed after the C4 step. In step C8, as shown in FIG. 8A, the first switch 23 is continuously turned on, the magnetron 5 is continuously driven, and heating at a maximum high-frequency output of 800 W is started.
Then, steps C2 to C4 and C8 are cyclically executed.

Such circulation execution ends when the heating time relating to the maximum high-frequency output becomes 0, and the high-frequency output is not continuously set, so that the C7 step is performed after the C6 step, and the first switch 23 is executed. Is stopped, the heating is terminated, the second switch 24 is turned off, and the cooling of the magnetron 5 and the like is stopped.

Thus, the rapid heating for three minutes is completed. During the heating, the cooling device 8 is driven to cool the magnetron 5 and the like, and the magnetron 5 and the like do not reach an abnormally high temperature.

On the other hand, if the heating time for the maximum high-frequency output 800W corresponding to the rapid heating is erroneously set to exceed the above-mentioned predetermined time of 5 minutes, this is determined in step B5 in FIG. 6, and the start key 21 is operated. However, the routine of FIG. 7 is not executed and heating is not started. By the way, in such rapid heating, a heating time of 5 minutes is sufficient.

Here, the rated value of the high-voltage capacitor 7 is larger than usual, whereby the maximum high-frequency output when the magnetron 5 is continuously driven as described above is 80.
Since it is as large as 0 W, rapid heating is possible and the heating time can be shortened. In this case, the amount of heat generated by the magnetron 5 and the like increases. However, the cooling device 8 has not been increased in size to follow this, and the cooling performance has not been improved. Therefore, as described above, when the magnetron 5 is continuously driven for more than a predetermined time of 5 minutes, the magnetron 5 is not driven.
And the like become abnormally high temperature despite being cooled by the cooling device 8.

In view of this, if the heating time for the maximum high-frequency output 800W corresponding to rapid heating is erroneously set to exceed the predetermined time of 5 minutes as described above, as shown in FIG.
Since the start of heating is prohibited based on the determination in step B5, the size of the magnetron 5 can be increased without increasing the size of the cooling device 8 in order to improve the cooling performance of the cooling device 8.
And the like are prevented from becoming abnormally high. Since the size of the cooling device 8 is not increased, the cost of the microwave oven is not increased.

As can be seen from the above, the step B5 corresponds to the prohibiting means of the present invention.

Note that setting another high-frequency output before the maximum high-frequency output of 800 W, and performing heating by the other high-frequency output and heating by the maximum high-frequency output continuously are also refused in the above B2 step and are prohibited. That is, the magnetron 5 and the like may be at an abnormally high temperature even during such combined heating.

Further, another high-frequency output is set after the maximum high-frequency output of 800 W, and heating with the maximum high-frequency output and heating with another high-frequency output are continuously performed. Since there is no step in which another high-frequency output can be set, the operation is similarly prohibited. Of course, also in this case, the magnetron 5 and the like may be at an abnormally high temperature.

(G) Effects of the Invention According to the present invention, in increasing the maximum high-frequency output during continuous driving of the high-frequency generator, the amount of heat generated by the high-frequency generator increases, but the size of the cooling device that cools the high-frequency generator is increased. It is possible to eliminate the necessity of improving the cooling performance. Therefore, it is possible to shorten the heating time without incurring the cost associated with the increase in the size of the cooling device, and to provide an extremely practical high-frequency heating device. .

[Brief description of the drawings]

The drawings relate to a microwave oven according to an embodiment of the present invention, wherein FIG. 1 is an external perspective view, FIG. 2 is a right side sectional view, FIG.
FIG. 4 is a circuit diagram, FIGS. 5, 6, and 7 are flowcharts of operation programs incorporated in the control unit, and FIG.
FIG. 6 is an operation timing chart of the switch. 3 ... heating room, 5 ... magnetron, 8 ... cooling device,
11 ... keyboard, 22 ... control unit.

Claims (1)

(57) [Claims] 1. A heating chamber for accommodating an object to be heated, a cooling device, and a high frequency supplied to the heating chamber while being cooled by the cooling device. A high-frequency generator, a driving mode setting unit, a time setting unit for setting a time according to a set driving mode by the driving mode setting unit, and a setting to continuously drive the high-frequency generator by the driving mode setting unit. And a prohibiting means for prohibiting the continuous driving when the time set by the time setting means exceeds the predetermined time.