JPS6157534B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooking time control device for a microwave oven.

Figure 1 is an external view of a conventional microwave oven, and the operation panel 1 of the microwave oven has a cooking menu table 2 and a timer knob 3 related to the menu table.
There is. FIG. 2 is a partially enlarged view of the menu table 2, and the timer knob 3 is used to set the movable timer pointer 6 to the amount indicated for each dish, and the cooking start button 4 is pressed. Press to start cooking.

In the example shown in Figure 2, the pointer is set so that two dishes of curry are reheated at the same time. Another button 5 above the start button 4 is a button for switching high frequency output, and is used, for example, when defrosting frozen foods. Also, if it is a gas oven, it can be thought of as a button to switch the amount of gas burned. As can be seen from the example in Figure 2, the timer's pointer is designed so that the optimum cooking time can only be set after selecting the dish and quantity. Therefore, food stored at the bottom of the refrigerator at around -5°C may not be heated enough, and food left indoors during the hot summer heat may become overcooked and taste unpleasant. There were many points. In addition, when dozens of menu items were written on the menu table, the font became too small, which caused many inconveniences, such as making it difficult to set the pointer or setting it incorrectly.

The present invention solves the above-mentioned conventional drawbacks, and one embodiment of its structure and operation will be described with reference to FIGS. 3 to 10.

Note that the same members as in the conventional example will be described with the same reference numerals.

Figure 3 is a schematic diagram of the operation panel of the microwave oven, Figure 4 is a sectional view of the main parts of the heating chamber, and Figure 5 is the control circuit.This microwave oven uses a magnetron 33 to heat food at high frequency. This is an example.

To explain Fig. 4, 32 is a heating chamber, 33
After being cooled by a fan 34 using a magnetron, the air is sent into the heating chamber 32 through a duct 35, and is discharged to the outside of the main body through an exhaust duct 37 together with steam generated from the food 36.
A sensor element 38 for detecting humidity is arranged inside the exhaust duct 37. The operation method will be explained with reference to FIG. 3. When performing automatic cooking using the sensor element 38, set the timer knob 3 to the automatic position, then turn the transverse dial 8 at the left end of the cooking menu table 2 and turn the needle 6. Match with the specified dish. In Fig. 3, when the pointer is aligned with the stew position and the cooking start button 4 is pressed, the food is heated and steam begins to be produced regardless of the amount of food or the initial temperature, and the sensor element 38 detects the steam to provide optimal cooking. The time is set. Sensor element 38
has the characteristics as shown in Figure 6, and as the temperature of the food rises and steam begins to be generated, the relative humidity around the sensor element 38 (Figure 7) increases and the sensor element 38
The resistance value R _S changes rapidly.

Next, the operation will be explained based on the control circuit diagram shown in FIG.

When the cooking start button is pressed, the contact 39 linked to the button closes, and information to start cooking is transmitted to the _K1 input terminal of the control device 40 using a microcomputer. Therefore, a command is issued to the relay 41 from the P _O output terminal, and the contact 49 of the relay 41
closes. A voltage is applied to the high voltage transformer 42,
A high frequency oscillation circuit 43 including a magnetron operates to perform cooking.

On the other hand, when the cooking start button is pressed and the contact point 39 closes, the switching circuit 48 is activated for several milliseconds by the signal from the output terminal _P1 , and the variable speed control fixed to the axis of the transverse dial 8 (see Fig. 3) is activated. Resistance value R _V of resistor 44 and capacitance C of capacitor 45
The operational amplifier 46 oscillates at a unique frequency determined by . This oscillation circuit 47 is connected to the input terminal K _O of the control device 40 using a microcomputer, so when one dish is selected from the cooking menu table by turning the transverse dial 8, the variable resistor 4
Since the resistance value R _V of 4 changes, and therefore the oscillation frequency changes, information regarding which dish has been selected is input to the control device 40. When this information is taken in, the switching circuit 48 is activated by a signal from the output terminal P ₁ of the control device 40, and the variable resistance circuit is disconnected, and the value is determined by the sensor resistance R _S and the capacitance C of the capacitor 45 instead. The oscillation circuit 47 operates at a unique frequency. The oscillation frequency at this time is processed as oscillation frequency information during cooking by a counter circuit (not shown) using a microcomputer via an input terminal _KO . For example, the oscillation frequency when selecting a food menu
If _M and the oscillation frequency _C during cooking match, or
A certain function of _C or _M , i.e. _C = φ( _M )
If the cooking is programmed to end when the temperature reaches 100, a signal is generated from the output terminal P _O of the control device 40, the contact 49 of the relay 41 is opened, and the oscillation is stopped.

As shown in FIG. 3, when the transverse dial 8 is turned and the pointer 6 is used to select stew, cooking is performed in the pattern shown in FIG.
That is, for T minutes from the start of cooking until the temperature of the food rises and steam begins to be produced, the high frequency output is set to the maximum output (100%) and cooking is performed. During this time, the relative humidity around the sensor changes as shown in FIG. That is, from point S to point P, the transition is almost horizontal, and between point P and point E, steam suddenly starts to appear, and the relative humidity changes rapidly, and the resistance value R _S and oscillation frequency of the sensor element 38 also change at this point. changes rapidly. The control device 40 detects the generation of steam from this sudden change in frequency and calculates the optimum cooking time (KT) for cooking the stew from the time T taken until the steam is generated. Also, if the high frequency output is reduced to 1/3 at the steam generation point E, the meat will become softer and the taste will be even better. Since the control device 40 has a built-in microcomputer, it can store programs for optimal cooking, calculate the optimal time like a desktop calculator, and send commands to change the high frequency output to the optimal level. It can have many functions such as emitting at the right timing. In the case of Fig. 8, the remaining time after the steam is released is multiplied by K, and the value of K is the value of the variable resistor 4 when the transverse dial 8 is turned.
The control device 40 judges from the value of the resistance R _V of No. 4 that K
The additional cooking time is determined by calculating the value and then multiplying the time by KT.

If the situation is selected as shown in FIG. 9, the resistance value R _V of the variable resistor 44 will be about 180 (KΩ), and the value of K will be about 2.5. =φR _V ) is required to be stored in memory.

FIG. 9 shows a comparison between the menu table 2 of the operation panel 1 and the information stored in the memory area of the computer.

For example, in the case of simply reheating a pre-cooked dish, that is, in the reheating range, the time coefficient K is continuously variable from 0 to 0.3. In this section, the coefficient K is the resistance value R _V of the variable resistor 44 when the transverse dial 8 is turned and the pointer 6 is moved to the right.
If the relational expression K=φ(R _V ) is programmed and stored in the memory area of the computer in advance up to 40KΩ, the value of K can be calculated automatically. The high frequency output reduction coefficient m is m = 1 in this section, which means that the output is the same from beginning to end, and m = 1 when the resistance value R _V of the variable resistor 44 is between 1 and 40KΩ. All you have to do is store what will happen in the memory area.

Next, in the case of vegetables, we divide them into leafy vegetables such as spinach and kiyabetsu, and root vegetables such as sweet potatoes and potatoes.Even if the resistance value R _V of the variable resistor changes, the value of K Value R _V is 40~85KΩ
If the resistance value R _V is between 80 and 170KΩ, it is better to fix the value of K to 0.3 and fix the value of K to 1 for better cooking results.

On the other hand, when stewed food is selected, this area is the same as the reheating area, and as the resistance value R _V of the variable resistor changes, the time coefficient K changes from 2.5 to 5 in proportion to it.

In this way, when one dish is selected from Menu Table 2, the heating time coefficient K and output reduction coefficient m suitable for it can be set, and optimal cooking can be performed.

To supplement the above explanation, the positional relationship between the transverse dial 50 and the variable resistor 51 will be explained with reference to FIG. 10. The transverse dial 50 for selecting dishes
A wheel 54 for driving a variable resistor 51 and a pointer 57 of a menu table 52 is directly connected to the shaft. Therefore, the pointer 57 can be moved left and right by the rotation of the wheel 54 via the threading roller 55 and the thread 56.

That is, when one menu in the menu table 52 is selected with the pointer 57, the corresponding resistance value R _V of the variable resistor 51 is determined, and therefore the oscillation frequency of the oscillation circuit 47 shown in FIG. 5 is determined. Based on this information, the control device 40 selects a control method from those shown in FIG. 9, determines the time and high frequency output, and performs control. If the menu table 52 is made of a transparent material and an illumination lamp (not shown) is attached to the back, the menu table 52 can be easily raised to make it easier to see. Third
In the figure, when the timer knob 3 is set to the automatic position, the illumination lamp lights up, making it even more convenient to use.

When cooking a dish that is not on the menu table 52, for example, thawing frozen food, it is often not desirable to heat it until steam is produced, in which case it is sufficient to manually set the optimum time for cooking. The operating method in this case is the same as the conventional one, so the explanation will be omitted.

Also, the optimum temperature for reheating soup (60~
If you want to set the temperature a little higher than 70℃ (70℃), move the pointer slightly to the right. For example, you can move it to the position of the cold rice. Such fine adjustment is possible in the variable region (FIG. 9).

As explained above, according to the present invention, the following effects can be expected.

1. Since the cooking time can be automatically set, it is easy to use and anyone can easily use it.

2. The optimal cooking time is automatically set based on the initial temperature of the food (temperature just before heating) and the amount of food, which not only simplifies operation but also allows for accurate cooking without mistakes.

3. It is easy to obtain a finished product according to each person's preference, and the settings are also easy.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a conventional microwave oven, Fig. 2 is a front view of a portion of the main operation panel, and Fig. 3 is an operation panel of a microwave oven according to an embodiment of the present invention. Figure 4 is a longitudinal cross-sectional view of the microwave oven, Figure 5 is the main control circuit diagram of the microwave oven, and Figure 6 is the characteristic showing the relationship between humidity and time when food is heated in the microwave oven. Figure 7 is a characteristic diagram of the sensor, Figure 8 is a diagram showing the relationship between the output of the microwave oven and time, and Figure 9 is a diagram showing the cooking menu in the microwave oven and the information stored in the memory area of the computer. FIG. 10 is a front view of the cooking time control device of the microwave oven. 1...Operation panel, 2,52...Cooking menu table, 8,50...Transverse dial, 38...Sensor, 40...Control device (including microcomputer and measuring means), 44,51...Variable resistor .

Claims (1)

[Claims] 1 A cooking menu table and a transverse dial for selecting the cooking menu are provided on the operation panel on the front of the main body, and a variable resistor that changes according to the rotation of the transverse dial and a sensor element that directly or indirectly detects the humidity of the food are provided. means for measuring the resistance value of the sensor element and the resistance value of the variable resistor, and a configuration for calculating the additional cooking time and high frequency output by a microcomputer based on the output from the measuring means, and controlling the high frequency output. At the same time, the cooking menu displayed on the cooking menu table,
The cooking time of a microwave oven is characterized in that the cooking menu is divided into blocks using high-frequency output optimal for cooking, and the cooking menu is written in the order of coefficients that determine the length of cooking time after a specified amount of steam is detected by a humidity sensor. Control device.