JPH0317132Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> The present invention relates to a microwave oven and a heater such as a microwave oven or a gas range in which a heater is added to the microwave oven.

<Prior Art> In recent years, various sensors have begun to be used in the above-mentioned heaters to enable automatic cooking. Among them, there is one that automatically finishes cooking regardless of the amount of food by measuring the weight of the food (the object to be heated) and adding a heating time corresponding to the weight of the food. In this case, the weight of the food is automatically measured by placing it in the heating chamber.
At this time, it is necessary to perform the measurement function itself with high precision. However, when a measuring function is added to a microwave oven, microwave oven, etc., the environment of the measuring device is extremely poor, making it impossible to measure accurately.

In other words, in a microwave oven, the measuring device is installed at the bottom of the heating chamber.
The ambient temperature is close to 80 degrees Celsius, and food must be weighed on a rotating plate (turntable), so the mounting of the weighing device itself is unstable, making accurate measurements impossible. This can be improved by always adjusting the weight without food to zero before weighing, but if you reset the weighing device to zero every time you cook, the automatic cooking will be worse than before. This results in complicated handling.

<Purpose> The present invention maintains accuracy even when the ambient temperature in the heating chamber is high by automatically zeroing the weighing device, that is, updating the weight calculation reference value of the arithmetic control circuit when the door is opened and closed. The purpose is to provide a heater that can calculate the heating time.

<Example> Hereinafter, an example in which the present invention is applied to a microwave oven consisting of a microwave oven and an electric heater will be described based on the drawings.

In the electric circuits shown in Figures 1 and 2, 1 is an oscillation circuit for generating microwaves from a magnetron;
1a is a fan motor for cooling the oscillation circuit; 2
are electric heaters in the heating chamber, which constitute a heating means for heating the object (food) on the turntable rotated by the motor 3, and can be operated by turning on the heating switch 4. The oscillation circuit 1 is controlled by the ON/OFF of the range switch 5, the electric heater 2 is controlled by the ON/OFF of the heater switch 6, the motor 3 is controlled by the switch 3a, and these switches 5, 6 and 3a are controlled by an arithmetic control circuit 7. Reference numeral 8 denotes a measuring device (including a rectifying circuit) for measuring the weight of the object to be heated (including the container), and this is constructed as shown in FIG. That is, the pair of upper and lower leaf springs 12 are elastically deformed in accordance with the turntable support shaft 11 which is vertically movable according to the weight of the heated object 10 on the turntable 9 supported on the turntable pedestal 9a. One end of the leaf spring 12 is fixed to the bottom of the wall of the heating chamber 16 via a fixing plate 13, a fixing frame 14, and a radio wave leakage prevention box 15.
The other end is connected to the protrusion 17a of the spacing piece 17 and the movable frame 18.
The lower part of the shaft 11 is rotatably engaged with the lower part of the shaft 11 by a bearing 19. A fixed electrode 21a is placed at the bottom of the fixed frame 14 via an insulator 20, and an insulator 2 is placed at the bottom of the movable frame 18.
A movable electrode 21b is fixed via 2.

With the above structure, the gap between the pair of electrodes 21a and 21b changes depending on the weight of the food, and this electrode 2
The capacitance between 1a and 21b changes. This capacitance is represented by the weight detection capacitor C1 in the electrical circuit of FIG. 2, and the oscillation frequency of the output changes depending on the value of this capacitor C1 and the functions of the operational amplifiers IC1, IC2, etc. The oscillation frequency is detected by the arithmetic control circuit 7 shown in FIG.

In addition, in Figure 1, by opening and closing the door of the heating chamber,
The ON/OFF signal of the door switch 23 is input to the arithmetic control circuit 7 consisting of a microcomputer, and the weight G of the object to be heated and the heating time T (for example, T=G/a+b) are calculated based on the output of the measuring device 8 when the door is opened/closed.
is calculated by the calculation control circuit 7. The calculation control circuit 7 also has a function (zero adjustment function) of updating the weight calculation reference value based on the output signal of the weighing device 8 when the door is opened before heating (or when the door is closed after heating). ing.

The control device A is composed of the arithmetic control circuit 7 and the switches 4, 5, 6, 23, and 1a. 24 is a menu set key connected to the arithmetic control circuit 7, and 25 is a power outlet.

Further, the arithmetic control circuit 7 is configured as shown in FIG.
Weighing device 8 in a state where the object to be heated 10 is not placed on the turntable 9 when the power is turned on
A storage means 30 stores an initial value F0 for zero adjustment as a reference value for weight calculation;
a zero adjustment reweighing means 31 that measures the zero adjustment reweighing value F1 by the measuring device 8 when the turntable 9 is stationary when turned off; a reweighing value F1 measured by the zero adjustment reweighing means 31; Comparing and determining means 32 that compares the initial value F0 stored as the weight calculation reference value in the storage means 31 and determines whether the difference is within a certain value or not.
and, in the comparison and determination means 32, the initial value F0
When it is determined that the difference between the reweighed value F1 and the reweighed value F1 is within a certain value, it is determined that the object to be heated 10 is not placed on the turntable 9, and the weight calculation reference value is set to the initial value F0. When the weight calculation reference value updating means 33 updates the weight calculation reference value F1 from the initial value F0 to the reweighing value F1, and the comparing and determining means 32 compares and determines that the difference between the initial value F0 and the reweighed value F1 is greater than a certain value, the turntable Heated object 10 on top of 9
weight calculation reference value continuation means 34 that determines that the weight is placed thereon and uses the initial value F0 as the weight calculation reference value; When the heating switch 4 is turned on with the heating switch 4 turned on, the weighing device 8 calculates the weight G of the object to be heated 10 and the weight determined by the weight calculation reference value updating means 33 or the weight calculation reference value continuation means 34. A total weight measuring means 35 that measures the total weight F2 with the calculation reference value F0 or F1, the total weight G measured by the total weight measuring means 35, and the weight calculation reference value updating means 33 or the weight calculation reference value continuation. heating time determining means 36 for determining the heating time T by the heating means based on the difference from the weight calculation reference value F0 or F1 determined by the means 34; Heating control means 37 for controlling driving
It is required to have.

Next, the action will be explained.

Normally, when cooking food (an object to be heated), the door of the heater is opened, the food is placed in the heating chamber, the door is closed, and the food is cooked. When the cooking is finished, the door must be opened, the food taken out, and then closed again. Therefore, when the door is opened and closed during cooking, it is only necessary to detect when no food is placed on the turntable and perform zero adjustment (update the weight calculation reference value) each time. Now, when I cook using the above operation, there are two times when there is no food on the turntable. That is, when the door is opened before cooking starts, and when the door is closed after cooking is finished. Other than that, it is also possible to always perform zero adjustment at regular intervals, but this is not realistic.
It is better to perform zero adjustment during normal use.

However, when opening and closing this door, it is necessary to determine whether food is placed on the turntable. These will be explained using the flowchart of the measuring device 8 and the arithmetic control circuit 7 shown in FIG. Or have the user perform the zero adjustment only once. The measured value F0 at the time of zero adjustment by the weighing device 8 at this time is stored in the storage means 30 as a weight calculation reference value. Then, when cooking, when the door is opened and the door switch 23 is turned OFF (the turntable is in a stationary state), the zero adjustment reweighing means 31 weighs the measuring device 8 again, and the comparing and determining means 32 measures the value F1 at that time. Then, it is compared and determined whether the difference from the initial value F0 stored as the weight calculation reference value by the storage means 30 is within a certain value (for example, several tens of grams). If |F0-F1| is within a certain value, the zero adjustment is automatically performed, and the weight calculation reference value updating means 33 sets the value F1 as the weight calculation reference value.
In other words, when heating the food 10, the weight of the food is not just a few grams but several hundred grams, so it is weighed when the door is opened, and if the difference is within a certain value (several tens of grams), then the food weighs several hundred grams. , the weight calculation reference value updating means 33 automatically zeros the value, and if the value is above a certain value, the food 10 is placed on the turntable 9, so the value F0 is changed to the weight by the weight calculation reference value continuation means 34. It should be continued as a calculation reference value and should not be zeroed.

Next, put the food (including the container) into the heating chamber,
With the door closed and door switch 23 turned on,
Turn on heating switch 4. Then, the total weight measuring means 35 operates the weighing device 8 to measure the total weight F2 of the food weight G and the weight calculation reference value (F0 or F1), and inputs the output signal to the calculation control circuit 7. In the arithmetic control circuit 7, the heating time determining means 36 converts the weight G of the food into the total weight F.
2 and the weight calculation reference value (F0 or F1), and based on this weight G, set the heating time T for microwave heating or electric heater heating according to the signal from the menu select key 24, for example, T. =
Calculate as G/a+b. Then, the range switch 5 and the heater switch 6 are controlled by the arithmetic control circuit 7 to perform heating for a predetermined heating time, and then the heating control means 37 stops the heating.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

<Effects> As is clear from the above explanation, the arithmetic control circuit according to the present invention converts the initial value of zero adjustment by the weighing device when the object to be heated is not placed on the turntable to the weight when the power is turned on. a storage means for storing a calculation reference value; a zeroing and reweighing means for measuring a zeroing and reweighing value using a weighing device when the turntable is stationary when the door is opened and the door switch is turned off during cooking; and the initial value. and a reweighed value, and a comparison and determination means that determines whether the difference is within a certain value; weight calculation reference value updating means that determines that no object to be heated is placed on the turntable and updates the weight calculation reference value from the initial value to the reweighed value when the object is weighed; When it is determined that the difference between the initial value and the reweighed value is greater than a certain value, it is determined that the object to be heated is placed on the turntable, and the initial value is used as the weight calculation reference value. and weight calculation reference value continuation means.

Therefore, during cooking, when the door is opened and closed, and when there is no object to be heated on the turntable, it is detected and the weighing device is zeroed, that is, the weight calculation reference value of the arithmetic control circuit is set. By automatically updating, even if the ambient temperature in the heating chamber is high, the heating time can always be calculated accurately.

In addition, when it is detected that an object to be heated is placed on the turntable when the door is opened or closed, the initial zero value is continued as the weight calculation reference value, so the object to be heated on the turntable can be continuously replaced. Even in the case of cooking, the heating time can be adjusted according to the weight of the heated object that has been replaced.

[Brief explanation of the drawing]

Figure 1 is an electrical circuit diagram of an embodiment of the heater of the present invention.
Figure 2 is an electrical circuit diagram of the metering device, Figure 3 is a sectional view showing the mechanical structure of the metering device, Figure 4 is a flowchart for controlling the heater, and Figure 5 is a functional block diagram of the arithmetic control circuit. It is a diagram. A: Control device, C1: Weight detection capacitor, 1: Oscillation circuit, 2: Electric heater, 3: Motor, 3a: Motor switch, 4: Heating switch, 5: Range switch, 6: Heater switch, 7: Arithmetic control Circuit, 8: Measuring device, 9: Turntable, 10: Heated object (food), 11: Turntable support shaft, 12: Leaf spring, 1
6: heating chamber, 21a: fixed electrode, 21b: movable electrode, 23: door switch, 24: menu set key, 25: power outlet, 30: storage means,
31: Zero adjustment reweighing means, 32: Comparison determination means,
33: Weight calculation reference value updating means, 34: Weight calculation reference value continuation means, 35: Total weight measuring means, 3
6: Heating time determining means, 37: Heating control means.

Claims (1)

[Claims for Utility Model Registration] A heating chamber for heating an object to be heated, a turntable that is installed in the heating chamber so as to be movable up and down and on which the object to be heated is placed, and a turntable for opening and closing the heating chamber. A door, a door switch that turns on and off when the door is opened and closed, a heating means for heating the object to be heated, and a turn table that moves up and down in accordance with the weight of the object to be heated. It comprises a weighing device that measures weight, and a control device that includes a calculation control circuit that calculates a heating time based on an output signal of the weighing device and controls the heating time of the heating means, and the calculation control circuit is powered on. In some cases, there is a storage means that stores the initial value set by the weighing device when the object to be heated is not placed on the turntable as the weight calculation reference value, and when cooking, the door switch is turned on when the door is opened.
When the turntable is turned OFF, the zero adjustment reweighing means measures the zero adjustment reweighing value using a measuring device while the turntable is stationary, and the initial value and the reweighing value are compared and it is determined whether the difference is within a certain value. and when the comparison and determination means compare and determine that the difference between the initial value and the re-weighing position is within a certain value, no object to be heated is placed on the turntable. The weight calculation reference value updating means updates the weight calculation reference value from the initial value to the reweighed value, and the comparison determination means determines that the difference between the initial value and the reweighed value is equal to or greater than a certain value. weight calculation reference value continuation means that determines that an object to be heated is placed on the turntable and sets the initial value as a weight calculation reference value; When the heating means is driven with the door closed and the door switch turned on, the total weight measured by the weighing device and the weight calculation determined by the weight calculation reference value updating means or weight calculation reference value continuation means are calculated. The heating time determining means for determining the heating time by the heating means based on the difference from a reference value, and the heating control means for controlling the driving of the heating means based on the heating time by the heating time determining means. Features a heater.