JPH0415684B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a rice cooking method in which a microcomputer constitutes a control circuit for controlling multiple processes such as preheating and rice cooking based on pan temperature information etc. from a temperature sensor. Concerning the method of controlling the device.

[Technical background of the invention and its problems]

Conventionally, a control circuit configured using a microcomputer performs a preheating process to preheat a pot and allow the rice in the pot to absorb sufficient moisture, and subsequently performs a rice cooking process, a rice shading process, and a rice cooking process. A rice cooker is available in which the warming steps are executed in this order, and in this case, each step is controlled based on pot temperature information from a temperature sensor, a clock signal, etc. However, in such a configuration, the preheating process to the warming process are always performed every time rice is cooked according to a program stored in advance in the control circuit, so for example, if you want to skip the preheating process and start from the rice cooking process, There is a problem in that it is not possible to satisfy these demands when only the steaming process is desired for re-steaming rice, etc.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its object is to provide a rice cooker configured to sequentially execute a preheating process, a subsequent rice cooking process, a steaming process, and a warming process by a control circuit comprising a microcomputer. When controlling the rice cooker, any one of the preheating, rice cooking, steaming, and warming steps can be started by simply repeating the operation of the same external operating means, It is an object of the present invention to provide a control method for a rice cooker that can improve the usability of the rice cooker and has effects such as being able to prevent erroneous operations when selecting a stroke as described above.

[Summary of the invention]

The present invention provides a rice cooker in which a preheating process, a subsequent rice cooking process, a steaming process, and a warming process are sequentially executed by a control circuit composed of a microcomputer, in which a plurality of control patterns each having a different execution start process are executed in the same manner. An automatic return type external operation means selected by multiple operations of the operation part is provided as an input means for the control circuit, and the execution start process of the selected control pattern is displayed on a display. This allows any process to be executed.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 1, 1 is a rice cooker main body consisting of an inner case 2, an outer case 3, etc., 4 is a lid, 5 is a pot housed in the inner case 2, 6 is a heater for cooking rice, and 7 is a heater for keeping warm. . 8 is a cup-shaped heat-sensitive part provided so as to be in thermally conductive pressure contact with the outer bottom of the pot 5;
A thermistor 9 serving as a temperature sensor is heat-conductively attached inside the pot 5, so that the temperature of the pot 5 can be sensed by the thermistor 9. Reference numeral 10 denotes a case disposed on the outer bottom of the rice cooker main body 1, and a control circuit 11 and the like whose circuit configurations are shown in FIGS. 2 and 3 are housed inside the case.
Further, 12 is a light emitting diode for displaying the preheating process;
13 is a light emitting diode for displaying the rice cooking process, 14 is a light emitting diode for displaying the rice cooking process, and 15 is a light emitting diode for displaying the warming process. In FIG. 2, a plug 16 is inserted into a power outlet (not shown), and a rice cooking heater 6, a heat-retaining heater 7, and relay switches 17 and 18 are connected between both terminals of the plug as shown.
The relay switches 17 and 18 are of a normally open type and are turned on only when the corresponding excitation coils 19 and 20 are energized. 21 is a DC power supply circuit, which includes a transformer 22 that steps down the voltage between both terminals of the plug 16, a bridge type full-wave rectifier 23,
Smoothing capacitor 24, constant voltage circuit 2 with well-known configuration
5, outputs a DC low voltage between lines _L1 and _L2 , with the line _L1 side having a high potential. 26 is a temperature detection circuit that detects a change in the resistance value of the thermistor 9 (that is, temperature information of the pot 5), which outputs a temperature signal Sa corresponding to the temperature of the pot 5 and outputs a temperature signal Sa to the input terminal I of the control circuit 11. Give to ₁ . Reference numeral 27 denotes an automatic return type push button switch which is an external operation means, and is connected between the line _L1 and the input terminal _I2 of the control circuit 11. 28 is a drive circuit consisting of inverters 29, 30 and the excitation coils 19, 20, and this drive circuit 28 is connected to line L1 and control circuit ₁ along with resistors 31 to 34 and light emitting diodes 12 to 15.
1 and output terminals Q ₁ to Q ₆ as shown in the figure.

The control circuit 11, which is provided to be supplied with power from the lines _L1 and _L2 , is composed of a microcomputer, and its configuration will be described below in the third section.
Explain according to the diagram.

That is, 35 is a pulse generating circuit which receives the voltage signal S ₁ input to the input terminal I ₂ via the chattering prevention circuit ₃₆ every time the push button switch 27 is turned on. In other words, the clock pulse Pc is output every time the push button switch 27 is turned on. 37 is a quinary counter that counts pulses, and when the power is turned on, the count value is initialized, and when the count value is ``0'', it outputs a logic value ``1'' signal from the output terminal _A0 . Similarly, the count values are “1”, “2”, “3”,
Output terminal A ₁ corresponding to each state in "4",
The configuration is such that a logic value "1" signal is output from each of A ₂ , A ₃ , and A ₄ . 38 and 39 are counters that start counting oscillation pulses from an oscillator (not shown) when receiving a trigger signal, and these counters sequentially output the counting contents. 40 to 45 are comparison circuits, which output a logic value "1" signal only when the input value to input terminal A is greater than or equal to the input value to input terminal B, and output a logic value "0" signal in other states. do.
46 is a first storage section in which the temperature signal is stored.
For example, a preheating temperature value D ₄₆ corresponding to 45° C. is stored in the dimension Sa. Reference numeral 47 denotes a second storage section in which a rice cooking temperature value D ₄₇ corresponding to, for example, 110° C. in dimension of the temperature signal Sa is stored. Reference numeral 48 denotes a third storage section, which stores a temperature value D ₄₈ for double cooking which corresponds to, for example, 100° C. in the dimension of the temperature signal Sa. 49 is a fourth storage section, which stores temperature signals.
For example, a temperature value D ₄₉ for keeping warm corresponding to 72° C. is stored in the dimension Sa. Reference numeral 50 denotes a fifth storage section, which stores a preheating time value T ₅₀ corresponding to the count value when, for example, 5 minutes have passed since the counter 38 started counting.
51 is a sixth storage section, which stores the counter 3.
An irregularity time value _T51 corresponding to the count value at the time point when, for example, 15 minutes have passed since the start of counting is stored. 52 to 55 are trigger circuits, which set the logic value "1" in synchronization with the rise of the input signal.
Outputs a trigger pulse Pt consisting of a signal. The pulse generation circuit 35, quinary counter 37, counters 38, 39, and comparison circuits 40 to 4 described above
5. Each storage unit 46 to 51 etc. is connected to an AND circuit 56 to
62, OR circuit 63, 64, inverter 65, 6
6. The inverter buffer circuits 67 to 72 are connected between the input terminals I ₁ and I ₂ of the control circuit 11 and the output terminals Q ₁ to Q ₆ as shown in the figure.

Next, regarding the operation of the above structure, the pot 5 shown in FIG.
The explanation will be made with reference to a temperature change characteristic diagram over time. Now, with a predetermined amount of rice and water stored in the pot 5, the lid 4 is closed and the plug 16 is inserted into a power outlet (not shown).
1 outputs a constant DC voltage between lines L ₁ and L ₂ , and the control circuit 11 is powered on. When the power is turned on in this way, the count value of the quinary counter 37 is initialized, so the quinary counter 37 outputs a logic value "1" signal only from its output terminal A ₀ (in the open state). exhibits a state of In this state, when the push button switch 27 is turned on only once at time _t1 in FIG. The count value of the quinary counter 37 is stepped to "1", and a logic value "1" signal is output from the output terminal _A1 of the quinary counter 37. Then, AND circuit 57
A logic value "1" signal is now input to one input terminal of the , and at this point, the temperature of the pot 5 is below 45°C, and the temperature signal Sa and the preheating temperature value are
Since the comparator circuit 41 that has compared D ₄₆ outputs a logic value "0" signal, the logic value "1" signal inverted by the inverter 65 is also input to the other input terminal of the AND circuit 57. Therefore, this
The output terminal of the inverter buffer circuit 72 (and thus the output terminal Q ₂ of the control circuit 11) which receives the logic value "1" signal outputted from the AND circuit 57 via the OR circuit 64 is at the level of the logic value "0" signal. (Low level), the excitation coil 19 is energized, the relay switch 17 is turned on, and the rice cooking heater 6 is energized to generate heat and a preheating process is started. The temperature of the pot 5 (and the water inside it) rises due to the start of such a preheating process, and when the temperature of the pot 5 reaches 45° C. (time t ₂ in FIG. 4), the comparison described above The circuit 41 now outputs a logic value "1" signal, and therefore the AND circuit 5
7 is inverted to a logic value "0" signal, and the inverter buffer circuit 72 outputs a logic value "1" signal. As a result, the excitation coil 19 is cut off and the rice cooking heater 6 is also cut off, and when the temperature of the pot 5 decreases below 45°C, a logic value "1" signal is output from the comparator circuit 41. The rice cooking heater 6 is then energized again, and by repeating this operation, the pot 5
The temperature of the water in the pot 5 and the temperature of the water in the pot 5 are maintained at about 45°C. On the other hand, when the temperature of the pot 5 first reaches 45°C, that is, when the logic value "1" signal is first output from the comparator circuit 41, the AND circuit 58
A logic value "1" signal is applied from the output terminal A1 of the quinary counter ₃₇ and the comparator circuit 41 to both input terminals of the AND circuit 58, so that the output of the AND circuit 58 is inverted to a logic value "1" signal. A trigger pulse Pt is output from the trigger circuit 52, and the counting operation of the counter 38 is started. Therefore, when 5 minutes have passed since the temperature of the pot 5 first reached 45°C (time
t ₃ ), the comparator circuit 42 that compares the count value of the counter 38 and the preheating time value T ₅₀ outputs a logic value “1” signal, so the trigger pulse Pt is output from the trigger circuit 53. Then, this trigger pulse Pt is received via the OR circuit 63.
The count value of the decimal counter 37 is stepped to ``2'', and the quinary counter 37 inverts the output of the output terminal <sub>A1</sub> to a logical value ``0'' signal and also outputs the output terminal A1.
Invert the output of A ₂ to a logic “1” signal. Therefore, the AND circuits 57 and 58 are connected to the inverter 65,
Passage of each output signal of the comparison circuit 41 is blocked, and at the same time, a logic value "1" signal is input to one input terminal of each of the AND circuits 59 and 60, and the corresponding
AND circuits 59 and 60 allow the output signals of inverter 66 and comparison circuit 43 to pass through, respectively. At this point, the temperature of the pot 5 is below 110°C, and the comparator circuit 43 that compares the temperature signal Sa and the rice cooking temperature value D ₄₇ outputs a logic value "0" signal, so the AND circuit 59 , the other input terminal also receives a logic value "1" signal inverted by the inverter 66. Therefore, this
The logic value "1" signal output from the AND circuit 59 causes the output terminal of the inverter buffer circuit 72 to fall to a low level, so that the rice cooking heater 6 is energized in the same way as described above, and the rice cooking process starts from the preheating process. will be moved to the process. In addition, during the preheating process, the logical value "1" from the output terminal _A1 of the quinary counter 37
The signal causes the output terminal of the inverter buffer circuit 71 (as a result, the output terminal Q ₃ of the control circuit 11) to fall to a low level, so that the light emitting diode 12 for indicating the preheating process is energized and lit.

When the temperature of the pot 5 reaches 115° C. (time t ₄ ) in accordance with the execution of the rice cooking process, the comparison circuit 43 that compares the temperature signal Sa and the rice cooking temperature value T ₄₇ outputs a logical value “1” signal. In order to output the signal, the output of the AND circuit 59 is inverted to a logic value "0" signal, and the inverter buffer circuit 72 outputs a logic value "1" signal. As a result, the excitation coil 19 and, in turn, the rice cooking heater 6 are cut off, thereby ending the rice cooking process and proceeding to the uneven process. Incidentally, during the rice cooking process, the inverter buffer circuit 6 is activated by a logic value "1" signal from the output terminal _A2 of the quinary counter 37.
7 output terminal (and by extension, the output terminal of control circuit 11)
_Q4 ) falls to a low level, so the light emitting diode 13 for displaying the rice cooking process is energized and lit.

Now, at the end of the rice cooking process, AND circuit 6
0 input terminals are given logic value "1" signals from the output terminal _A2 of the quinary counter 37 and the comparison circuit 43, respectively, and the output of the AND circuit 60 is inverted to a logic value "1" signal. , a trigger pulse Pt is output from the trigger circuit 54. Then, the counting operation of the counter 39 is started in synchronization with the rise of the trigger pulse Pt, and the count value of the quinary counter 37 that has counted the trigger pulse Pt is stepped to "3". As a result, the quinary counter 37 inverts the output of the output terminal A ₂ to a logic value "0" signal and inverts the output of the output terminal A ₃ to a logic value "1" signal.
60 respectively block the passage of the output signals of the inverter 66 and the comparison circuit 43, and at the same time
A logic value "1" signal is input to one input terminal of each AND circuit 61, 62, and the AND circuit 61, 6
2 allows each output signal of the comparator circuits 44 and 45 to pass through. When the temperature of the pot 5 becomes lower than 100°C at time t ₅ after the steaming process has started in this way, the temperature signal Sa and the double-cooking temperature value
A logic value "1" signal is output from the comparator circuit 45 that has compared T ₄₈ , and this logic value "1" signal passes through the AND circuit 62 and is input to the inverter buffer circuit 72 . Therefore, the rice cooking heater 6 is energized again to perform so-called double cooking heating, and in such double cooking heating, the temperature of the pot 5 reaches 100°C and the output of the comparison circuit 45 becomes a logic value "0" signal. The above-mentioned double-cooking and heating are performed multiple times during the unevenness process. Then, when 15 minutes have passed since the time t ₄ when the transition to the uneven stroke occurred (time t ₆ ), the comparator circuit 44 that compared the count value of the counter 39 and the uneven time value T ₅₁ outputs a logic value "1" signal. This logical value "1" will be output.
The signal passes through the AND circuit 61 and the trigger circuit 55
starts outputting a trigger pulse Pt, and the count value of the quinary counter 37 that receives this trigger pulse Pt is stepped to "4". Then, since the quinary counter 37 inverts the output of its output terminal A ₃ to a logic value "0" signal and inverts the output of its output terminal A ₄ to a logic value "1" signal, the AND circuits 61 and 62 respectively Passage of each output signal of the comparator circuits 44 and 45 is blocked, and at the same time, AND
A logic value "1" signal is input to one input terminal of the circuit 56, and the AND circuit 56 allows the output signal of the comparator circuit 40 to pass through, and the process proceeds to the next warming step. Incidentally, during the uneven stroke, the output terminal of the inverter buffer circuit 68 (and thus the output terminal Q ₅ of the control circuit 11) goes to a low level due to the logic value "1" signal from the output terminal A ₃ of the quinary counter 37. Because of this, the light emitting diode 14 for displaying the uneven stroke is energized and lit.

In the heat retention process, when the temperature of the pot 5 falls below 72°C, the temperature signal Sa and the heat retention temperature value T ₄₉
Since the comparator circuit 40 that compares the values outputs a logic value "1" signal, this logic value "1" signal passes through the AND circuit 56 and is applied to the inverter buffer circuit 70. Then, the output terminal of the inverter buffer circuit 70 (as a result, the output terminal Q ₁ of the control circuit 11) falls to a low level, so the excitation coil 20 is energized, the relay switch 18 is turned on, and the insulating heater 7 is energized. fever is generated. The temperature of the pot 5 is maintained at around 72° C. by controlling the energization of the heat retaining heater 7 by the comparison circuit 40, the inverter buffer circuit 70, and the like.
In addition, during the warming process, the output terminal of the inverter buffer circuit 69 (and thus the output terminal Q 6 of the control circuit ₁₁ ) falls to a low level due to the logical value "1" signal from the output terminal A ₄ of the quinary counter 37. Therefore, the light emitting diode 15 for displaying the warming process is turned on. Further, when the push button switch 27 is turned on after this, the count value of the quinary counter 37 that counts the clock pulses Pc output from the pulse generation circuit 35 is stepped to "0", so that Output terminal of advance counter 37
The outputs of A ₁ to _{A 4} are all set to logic value "0" signals, and the warming process is stopped.

As described above, when the push button switch 27 is turned on only once after the power is turned on to the control circuit 11, the first control pattern consisting of the preheating, rice cooking, uneven heating, and warming steps is selected, and the above-mentioned control pattern is selected. Although each process is executed sequentially, the control circuit 11
When the push button switch 27 is turned on twice after the power is turned on, two clock pulses Pc are output from the pulse generation circuit 35 and the count value of the quinary counter 37 is set to "2". A logic value "1" signal is now output from the output terminal _A2 of the counter 37, and as a result, the second control pattern in which the preheating process is skipped and the rice cooking process is started immediately is selected. . and,
After the control circuit 11 is powered on, the push button switch 27
When is turned on three times, the count value of the quinary counter is stepped to "3", so the third control pattern is selected in which the preheating process and rice cooking process are skipped and the steaming process is started immediately. Furthermore, when the push button switch 27 is turned on four times, a fourth control pattern is selected in which the warming process is immediately started, skipping the preheating process, rice cooking process, and steaming process. . In other words,
In the above-mentioned embodiment, a configuration is adopted in which an arbitrary control pattern can be selected from a plurality of control patterns by operating the push button switch 27, which is the same operation part, multiple times, and the control pattern selected in this way is Since the execution start process is displayed on the light emitting diodes 12 to 15, which are indicators, it is easy to select a control pattern by external operation, and it is also possible to prevent erroneous operations, which improves overall usability. This has the effect of improving the condition.

In the above embodiment, each step of preheating, rice cooking, etc. is sequentially advanced each time the push button switch 27 is turned on.However, each step is reversed each time the push button switch 27 is turned on. It's good as well.

〔Effect of the invention〕

As is clear from the above description, the present invention provides a rice cooker configured to sequentially execute a preheating process, a subsequent rice cooking process, a steaming process, and a warming process using a control circuit made up of a microcomputer. When controlling, it is possible to start any step among the preheating, rice cooking, steaming, and warming steps by simply repeating the operation of the same external operating means multiple times, This can produce excellent effects such as improving the usability of the rice cooker. Furthermore, according to the present invention, since the stroke selected by the operation of the external operating means is displayed on the display, it is also possible to prevent erroneous operations when selecting a stroke by the external operating means. be.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a partially cutaway vertical cross-sectional view, FIG. 2 is an overall circuit configuration diagram, FIG. 3 is a circuit diagram of main parts, and FIG. The figure is a temperature characteristic curve diagram for explaining the action. In the figure, 5 is a pot, 6 is a rice cooking heater, 9 is a thermistor (temperature sensor), 11 is a control circuit, 12 to 15
27 is a light emitting diode (indicator) and a push button switch (external operating means).

Claims (1)

[Claims] 1. In a rice cooker in which a microcomputer is used to configure a control circuit for sequentially executing a preheating process, a rice cooking process, a steaming process, and a warming process in which the pot is preheated based on pot temperature information etc. from a temperature sensor, the execution start process is An automatic return type external operation means for selecting a plurality of different control patterns by multiple operations of the same operation part is provided as an input means for the control circuit, and an execution start process of the selected control pattern is displayed on a display. A method for controlling a rice cooker, characterized in that a display is performed.