JP2792978B2 - High frequency heating equipment - Google Patents

Description

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

(B) Conventional technology The high-frequency generator in a general microwave oven disclosed in Japanese Utility Model Publication No. 55-50504 continuously operates with the maximum high-frequency information. Since the high-frequency generator is cooled by the cooling device, it does not reach an abnormally high temperature. Such operation is called high-frequency output operation with continuous rating.

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

However, in order to increase the cooling capacity, the size of the cooling device must be increased, resulting in an increase in the cost of the microwave oven. Therefore, without increasing the cooling capacity, while increasing the maximum high-frequency output of the high-frequency generator,
There is a high-frequency output operation with a short-time rating that limits the continuous operation time so that the high-frequency generator or the like does not become abnormally high. Even if the operation is continuously repeated even within the predetermined time limited by the short-time rating, the high-frequency generator becomes extremely hot.

(C) Problems to be Solved by the Invention The present invention aims to shorten the heating time without increasing the cost, and protects a high frequency generator and the like from abnormally high temperatures when repeatedly operated at a short-time rating. Things.

(D) Means for Solving the Problems A high-frequency heating device according to the present invention includes a heating chamber for accommodating an object to be heated, a high-frequency generator for generating a short-time rated or continuous-rated high-frequency output, Generation output setting means, time setting means for setting the operation time of the high-frequency device, and operation time for correcting the allowable operation time when the high-frequency generator is operated again with the short-time rated high-frequency output immediately after the operation. The prohibition means prohibits operation when the time set by the time setting means exceeds a predetermined time corrected by the operation time correction means when a short-time rated high-frequency output is designated.

(E) Function Even if the high-frequency generator is operated within a predetermined period of time with a short-time rating immediately after the high-frequency generator is operated, the high-frequency generator is at an abnormally high temperature because the initial temperature of the high-frequency generator is high. There are cases. However, if the short-time rating is specified again immediately after the high-frequency generator is operated, the allowable operating time in the short-time rating is corrected based on the immediately preceding operation state or the operation suspension time, and the set time is set. When the operating time exceeds the corrected operating time, the operation of the high-frequency oscillator is prohibited, so that the high-frequency generator can be prevented from becoming abnormally high.

(F) Embodiment FIGS. 1 and 2 show the structure of a microwave oven according to an embodiment of the present invention. In a microwave oven main body 1, a heating chamber 3 for accommodating a food 2 to be heated, and an electrical equipment room 4 are formed. In the electrical equipment room 4, a high frequency generator for supplying high frequency for heating the food 2 into the heating chamber 3, that is, a magnetron 5, a high voltage transformer 6 for applying high voltage power to the magnetron, and a high voltage A capacitor 7, these magnetrons 5, high voltage transformer 6, high voltage capacitor 7
And a cooling device 8 for cooling the cooling water. A door 9 for opening and closing the front opening of the heating chamber 3, a display 10, and a keyboard 11 are provided on the front surface of the microwave oven body 1.

Referring to FIG. 3, the display 10 has a number display section 12 for displaying a heating time and an operation mode display section 13 for displaying an operation mode of the magnetron 5. Keyboard 11 above
Is a generation output setting means for setting the generation output of the high-frequency generator, the rapid heating key 14 of short-time rated output 800W, 650W key 15, 450W key 16, 300W key 17, 15 of continuous rated output
0W key 18, 80W key 19, and time setting means for setting the heating time. , And a start key 21 for starting heating.

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, display drive control of the display 10 is performed, and the first and second switches 23 and 24 are turned on,
Performs off control. 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 that is turned on when the door 9 is closed. A high voltage is applied to the magnetron 5 via 7 or the like, 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, commercial power is applied to the cooling device 8 via the power fuse 25 and the door switch 26 to drive the cooling device 8, and the magnetron 5 and the high-voltage transformer 6 are driven. , The high-pressure condenser 7 is cooled.

The operation of such a microwave oven will be described with reference to FIGS. 5 and 6, which show the flow of an operation program incorporated in the control unit 22.

First, an outline of the operation will be described. Immediately after the operation of the high frequency generator, when the short-time rated operation is designated, the high frequency generator is proportional to the immediately preceding cooking operation time and inversely proportional to the pause time from the end of cooking. The initial temperature increases. Therefore, based on the immediately preceding operation time and the pause time from the end of cooking, the allowable time at the short-time rating is calculated, and when the set time at the short-time rating exceeds the calculated allowable operation time,
Prohibits heating and displays an error.

In FIG. 5, when the microwave oven is connected to the commercial power source, the memory of the control unit is initialized in step S1, and the maximum allowable operation time Tmax (5 in this embodiment) Minute) is set, and S2 step ~
Step S3 is performed in a cyclic manner.In step S2, it is determined whether or not the heating output setting keys 14 to 19 on the keyboard 11 and the numeric keys 20, 20, and ‥‥ for setting the heating time have been operated. At the same time, a pause time Ts from the end of the last cooking to the setting of new cooking conditions or the start of heating is measured. When cooking conditions are set on the keyboard 11,
After step S3, go to step S4. In step S4, it is determined whether the set heating output is a short-time rated rapid heating key (800W) or a continuous rating (650W or less). Transition. The heating output is set in the case of short-time rating, running S5~S8 step calculates the allowable operation time _{T 1 (T-Tc 1 +} kTs) in S5 step. That is, when the short-time rated operation is repeatedly executed, the immediately preceding allowable operation time T
From subtracting the previous cooking time Tc _1, by adding the allowable operation time increment based on the rest by multiplying the restored coefficient k in the rest time Ts time Ts, and calculates the allowable operation time T _1. Calculated allowable operation time T ₁ is, if it exceeds the maximum allowable time, S6～S7
After the step, the maximum value is set to 5 minutes.

In the allowable operating operation time T ₁ of the S5 step, depending on the heating output which is performed immediately before, correct the cooking time Tc _1,
It is desirable to subtract.

In step S8, it is determined whether or not the set time at the short-time rating exceeds the calculated allowable operation time.
An error is displayed in step S9, and the process returns to step S2 and cannot move to the start routine. However, in S8 step, if it is within the allowable operation time set time, the process proceeds to S10 step, and the memory the permissible operating time T _1, the process proceeds to the start routine of Figure 6.

In FIG. 6, in step S11, the start key 21
It is determined whether or not has been operated. When the start key 21 is operated to execute heating, S12, S13, S14, S15 or S16
The steps are circulated and the heating and cooking control is performed. S2
In one step, the second switch 24 is turned on to start driving the cooling device 8 to cool the magnetron 5 and the like, and to start counting down the cooking time Tc. In step S13, it is determined whether the count has become 0 based on the countdown of the cooking time. If it is not 0 in this case, then, in step S14, the set heating output is determined, and in step S15 or S16, the first switch 23 is set to a predetermined cycle every 30 seconds as shown in FIG. Turn on the time and drive the magnetron. For example, 80
At 0W, the first switch is turned on for 30 seconds in a 30-second cycle (continuous operation), and in the case of 650W, 450W, 300W, …… 26
Seconds, 18.4 seconds, 12.8 seconds, turn on. (Intermittent operation) Eventually, when the heating time related to the heating output becomes 0,
Such cyclic execution ends in step S13, and steps S17 to S18 are executed. In step S17, the on / off control of the first switch 23 is stopped, and the second switch 24 is turned off to stop cooling the magnetron 5 and the like. In step S18, the pause time counter is reset. At the same time, the cooking time executed for the subsequent allowable time correction is memorized, and the process shifts to the standby state of S2 to S3,
The pause time Ts is counted in preparation for the next cooking.

In the embodiment, the continuous operation is performed at the time of short-time rating, and the intermittent operation is performed at the time of continuous rating.

(G) Advantages of the Invention According to the present invention, the amount of heat generated by the high-frequency generator is increased by improving the maximum high-frequency output of the high-frequency generator. Therefore, the heating time can be shortened without incurring the cost associated with the increase in the size of the cooling device, and the operation state or operation immediately before the operation can be performed even if the cooling device is used repeatedly for a short time. Based on downtime,
The operation time allowed in the short-time rating is corrected, and if the set time exceeds the corrected operation time, the operation of the high-frequency oscillator is prohibited, so that the high-frequency generator becomes abnormally high temperature. And a very practical high-frequency heating device can be provided.

[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 and 6 are flowcharts of operation programs incorporated in the control unit, and FIG. 7 is an operation timing diagram of the first switch. 3 ... heating room, 5 ... magnetron, 8 ... cooling device,
11 ... keyboard, 22 ... control unit.

Claims (2)

(57) [Claims] 1. A heating chamber for accommodating an object to be heated, a high-frequency generator for generating a short-time or continuous-rated high-frequency output, a generation output setting means of the high-frequency generator, and an operation time of the high-frequency generator Time setting means for setting the operation time, the operation time correction means for correcting the allowable operation time when the high-frequency generator is operated again with the short-time rated high-frequency output immediately after operation, and the short-time rated high-frequency output is designated. And a prohibition means for prohibiting the operation when the time set by the time setting means exceeds a predetermined time corrected by the operation time correction means. 2. A heating chamber for accommodating an object to be heated, a high-frequency generator for supplying a high frequency to the heating chamber to generate a short-time or continuous-rated high-frequency output, and a generation output setting means of the high-frequency generator. Time setting means for setting the operation time of the high-frequency generator, pause time measuring means for measuring the time from when the high-frequency generator is operated to when it is operated again, and permissible operation during the short-time rated high-frequency output operation Operating time correction means for correcting the time based on the result of the downtime counting,
A high-frequency heating apparatus comprising: a prohibition unit that prohibits operation when the time set by the time setting unit exceeds a predetermined time corrected by the operation time correction unit when a short-time rated high-frequency output is designated.