JPH056449B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention executes an uneven process that includes a reheating operation in which the heating means is restarted at a predetermined time after the heating operation by the heating means is once stopped. The present invention relates to a method of controlling an electric rice cooker configured to do so.

[Technical background of the invention and its problems] In this type of rice cooker, when the inside of the pot becomes dry-up due to the execution of the rice cooking process in which the pot is heated by a rice cooker as a heating means, The rice-cooking heater is automatically turned off to end the rice-cooking process, and then, for example, when the temperature of the pot drops to a predetermined temperature, the rice-cooking heater is re-energized to perform an uneven process that includes a reheating operation. It is generally configured to
Conventional rice cookers are configured to fix the duration of the unevenness process including the above-mentioned reheating operation to a certain period of time. However, in such a conventional configuration,
If the amount of rice to be cooked is small and the amount of time the pot remains boiling is short, the time needed to turn the rice into alpha alpha may not be enough even if you add the time for the shading process. In this case, there is a possibility that delicious food cannot be obtained. Also,
If there is a large amount of rice to be cooked, the time in the pot will remain in the boiling state for a long time, and the rice will become alpha. When it comes to vessels,
Even in such a case, the unevenness process including the reheating operation is necessarily executed for a certain period of time, resulting in a problem of wasted power and time.

[Object of the Invention] The present invention has been made in view of the above circumstances, and its purpose is to automatically perform the unevenness process including the reheating operation for a necessary and sufficient amount of time depending on the amount of rice to be cooked. It can be adjusted, so that the rice in the pot can be alpha-ized without too much or too little, regardless of the amount of rice being cooked, so that delicious rice can always be obtained, and waste of electricity and time can be avoided. It is an object of the present invention to provide a control method for an electric rice cooker that has the following effects.

[Summary of the Invention] In order to achieve the above object, the present invention includes a temperature detection means that outputs a temperature detection signal according to the temperature inside a pot in which rice and water are stored, and a level of the temperature detection signal is set. a power-cutting means for cutting off the power to the heating means for heating the pot when the cooking temperature has been reached; and a heating means for turning off the power at a predetermined time after the heating means is cut off by the power-cutting means. In an electric rice cooker, the electric rice cooker is equipped with a reheating control means that executes an uneven process that includes a reheating operation of re-energizing the rice cooker. By controlling the heating control means to shorten the execution time of the unevenness process, the rice in the pot is alpha-ized in just the right amount, regardless of the amount of rice cooked.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In Fig. 2, 1 is the main body of the rice cooker consisting of an inner frame 2 and an outer frame 3, 4 is a lid, 5 is a pot removably housed in the inner frame 2, and 6 is a device for heating this pot 5. The heating means installed in the space between the bottoms of the inner frame 2 and the outer frame 3 is, for example, a rice cooking heater with a rated output of 600 watts. Reference numeral 7 denotes a heat-sensitive cap that is arranged so as to be able to move up and down so as to penetrate through the bottom of the inner frame 2. This cap is always urged upward by the spring force of a compression coil spring 8, so that the pot 5 is not moved inside. It is arranged so as to come into pressure contact with the outer bottom of the pot 5 while being housed in the frame 2. Reference numeral 9 denotes a thermistor as a heat-sensitive element installed in the heat-sensitive cap 7 to detect the temperature of the pot 5, and 10 indicates only when the pot 5 containing rice and water is housed in the inner frame 2. This is a pot switch that is turned on by being pressed by a heat-sensitive cap 7 to prevent dry cooking. Also, 11
is the operation panel installed on the side of the rice cooker body 1,
Reference numeral 12 denotes a case disposed at the outer bottom of the rice cooker main body 1, and inside this case 12 there is a control for controlling power on/off of the heater 6 based on the temperature detected by the thermistor 9 and input from the operation panel 11. circuit 1
3 is stored.

FIG. 1 shows the configuration of the control circuit 13 and its related parts that are directly related to the gist of the present invention, and will be described below.
In FIG. 1, the control circuit 13 is shown in terms of hardware by combining various functional parts; however, the present invention is not limited to this, and each of the functional parts described above can be replaced by a program of a microcomputer. Of course, this is also a good thing.

In FIG. 1, 14 is a switching element, for example, a triax, which is connected to an AC power source 15.
The heater 6 and the pot switch 10 are connected in series between both terminals of the pot switch 10 . Reference numeral 16 denotes a photocoupler consisting of a light emitting diode 16a and a phototransistor 16b, and the half wave voltage of the AC power source 15 is applied to the light emitting diode 16a through a diode 17 and a resistor 18.
Reference numeral 19 denotes a DC constant voltage circuit that receives the output of the AC power supply 15, and power is supplied to each circuit section described below from its output lines La and Lb.

20 is an initialization circuit consisting of, for example, a differential circuit;
This outputs an initialization pulse P ₀ every time the power is turned on. 21 is a waveform shaping circuit that shapes the output of the photocoupler 16 (voltage output corresponding to the half-wave output of the AC power source 15) into a rectangular wave, and 22 is a waveform shaping circuit that divides the output of this waveform shaping circuit 21 to generate a time signal, for example. 1
A first frequency divider circuit 23 generates a clock pulse _P1 with a period of seconds, and 23 is a second frequency divider circuit which divides the frequency of the clock pulse _P1 and outputs a clock pulse _P2 with a period of, for example, 10 seconds as a time signal. be.
24 is a temperature detection means 25 together with the thermistor 9.
This is the A-D converter that constitutes the thermistor 9.
outputs a digital temperature detection signal Sd corresponding to the detected temperature of the pot 5. Reference numerals 26 and 27 indicate first and second temperature value storage units that store numerical values corresponding to temperatures used to detect the amount of cooked rice, such as 70°C and 80°C, respectively; 28 indicates a predetermined lower limit temperature, such as 90°C;
A third temperature value storage section 29 stores numerical values corresponding to the boiling end temperature, and a fourth temperature value storage section 29 stores numerical values corresponding to, for example, 110.degree. Further, 30 to 39 are fifth to fourteenth temperature value storage sections, in which, for example, the following numerical values are stored, as shown in FIG. That is, the fifth temperature value storage unit 30 stores a value corresponding to 2°C, and the sixth, eighth, and eleventh temperature value storage units 31, 33, and 36 each store a value corresponding to 3°C. The seventh and tenth temperature value storage units 32 and 35 respectively store values corresponding to 1°C, and the ninth and twelfth temperature value storage units 34 and 37
are stored with values corresponding to 5°C, respectively, the 13th temperature value storage unit 38 stores values corresponding to 112°C as the heater power-off temperature Dz, and the 14th temperature value storage unit 39 stores values corresponding to 112°C. A value corresponding to 103°C is stored as the reheating operation start temperature Dr. 40
and 41 are first units that store numerical values corresponding to, for example, 2 minutes and 4 minutes, respectively, which serve as standards when detecting the amount of cooked rice.
and a second time value storage unit. 42 and 50 are third to eleventh time value storage units, which include the first
As noted in the figure, for example, the following numerical values are stored. That is, the third time value storage section 4
2 stores a numerical value corresponding to 7 minutes, the fourth time value storage section 43 stores a numerical value corresponding to 9 minutes, and the fifth and eighth time value storage sections 44 and 47 store a value of 0. Numerical values corresponding to seconds are stored in the sixth and ninth time value storage units 45 and 48, respectively, and numerical values corresponding to 10 seconds are stored in the seventh and tenth time value storage units 46 and 49. A numerical value corresponding to 20 seconds is stored in each case, and a numerical value corresponding to 30 seconds as the reheating operation reference time N is stored in the eleventh time value storage section 50. Further, 51a, 51b, and 51c are 12th to 14th time value storage units that store the duration time (unevenness time) of the uneven stroke, and as shown in FIG. Each value corresponding to 15 minutes, 13 minutes, and 11 minutes is memorized.

Reference numerals 52 to 64 are comparison circuits, which output a high level signal from the output terminal C when the respective input values to the input terminals A and B are in the relationship A≧B, and when A<B.
A low level signal is output from the output terminal C when the relationship is as follows. Further, 65 is a comparison circuit equipped with an enable terminal En;
It performs the same operation as the comparator circuits 52 to 64 only when receiving a high level signal at the enable terminal En, and always outputs a low level signal from the output terminal C when receiving a low level signal at the enable terminal En. 66 and 67 are subtraction circuits which subtract the input value to the input terminal E from the input value to the input terminal D, and output the subtraction result from the output terminal F. Addition circuits 68 to 71 add the input value to the input terminal X and the input value to the input terminal Y, and output the addition result from the output terminal Z. 72 to 75 are counters that count the number of pulses to the clock terminal CK and output the count value from the output terminal Q, and the count contents are initialized when a pulse signal is received at the reset terminal R. There is. Trigger circuits 76 to 79 output a trigger pulse _P3 for a short time when the input signal thereof rises.
80 is a delay circuit, which delays the input signal for a short time and outputs the delayed signal. Reference numeral 81 denotes a shift register having, for example, 24 unit registers, which transfers the input to the data terminal D to the first unit register 8 every time a pulse signal is received at the clock terminal φ.
1a and stores it, and each time new data is read, the old stored data is sequentially shifted to the upper unit register.When a pulse signal is received at the reset terminal R, the stored data is It is designed to be initialized. In the case of such a shift register 81, the 12th unit register 81b, the 18th unit register 81c, and the 24th unit register 81d.
It is configured to output each stored data. 82 is a memory circuit which is initialized when a pulse signal is received at its reset terminal R, and from this initialized state the input terminal D
The configuration is such that the value entered for the first time is stored. 83 outputs a gate signal Sg only when receiving a high level signal, and
A heater drive circuit 84 is a heater output control circuit that is driven only when receiving a high level signal.
For example, when driving, the duty ratio is 50%.
outputs a pulse-like control signal Sc. 85 to 1
Reference numeral 03 denotes a transfer gate, which becomes conductive only when a high level signal is received at the gate terminal.

Reference numerals 104 and 105 are a start switch for starting rice cooking and a stop switch for stopping rice cooking, which are provided on the operation panel 11, respectively.These are constituted by momentary type push button switches, and only when turned on, a pulse signal is sent to the corresponding line. (High level signal) _P4 and _P5 are output respectively. Further, 106 to 108 are R-S flip-flops, 109 to 118 are AND circuits, and 119
Reference numerals 121 to 121 are OR circuits, and 122 to 128 are inverters. Note that the first and second frequency dividing circuits 22,
23 and the AND circuit 111, the clock means 12
9 is configured, first and second temperature value storage units 26,
27, first and second time value storage units 40, 41, comparison circuits 52, 53, 56, 57, counter 72,
AND circuits 109, 112 and inverter 122,
123 constitutes the rice cooking amount detection means 103, and the fifth temperature value storage section 30, the comparison circuit 65, the subtraction circuit 66, the shift register 81, and the transfer gates 85, 86, and 87 constitute the boiling detection means 131. and a fourth temperature value storage section 29, third and fourth time value storage sections 42 and 43, and a comparison circuit 5.
5, 58, 59, counter 73, AND circuit 11
0 and 113 and inverters 124 and 125 constitute a boiling time measuring means 132, which includes a fourteenth temperature value storage section 39 and fifth to eleventh time value storage sections 4.
4 to 50, 12th to 14th time value storage units 51a
to 51c, comparison circuits 62, 63, 64, addition circuits 70, 71, counters 74, 75, trigger circuits 78, 79, transfer gates 95 to 10
3, AND circuits 117, 118 and inverter 1
28 constitutes a reheating control means 133,
Seventh to thirteenth temperature value storage sections 32 to 38, comparison circuit 61, addition circuits 68, 69, transfer gates 89 to 94, and R-S flip-flop 1
08 constitutes a power cutoff means 134, and further includes a sixth temperature value storage section 31, a comparison circuit 60, a subtraction circuit 67, a storage circuit 82, and a transfer gate 8.
8 constitutes a boiling detection compensation means 135.

Next, the effects of the above configuration will be explained in Figures 3 and 4.
This will be explained with reference to the drawings. In addition, Fig. 3 A and B
The temperature detected by the thermistor 9 (i.e. the pot 5
temperature) and the output of the heater 6, and FIG.
4,55,60,61,62,63,64,6
5. Heater output control circuit 84, start switch 104, R-S flip-flop 106, 10
7,108 each set output terminal Q, AND circuit 1
09, 110, 116, 118, OR circuit 121
Each output waveform is shown in correspondence with each code.

That is, when the pot 5 containing rice and the required amount of water is stored in the inner frame 2, the pot switch 10 corresponding to the storage is turned on. When the power is turned on in this state, the DC power supply circuit 19 and the photocoupler 16 are driven, and the initialization pulse P ₀ is output from the initialization circuit ₂₀ .
, the R-S flip-flop 106 is reset and a high-level signal is output from its reset output terminal, and this high-level signal initializes the counters 72, 74 and the memory circuit 82, and also resets the R-S flip-flop 106. 108 is reset. Also, at this time, the high level signal from the R-S flip-flop 106 is
Since the trigger pulse P ₃ is output from the trigger circuit 76 received via the OR circuit 120, the shift register 81 is initialized by the trigger pulse P ₃ , and the shift register 81 is also output via the OR circuit 120. The R-S flip-flop 107 is reset by the high level signal. After this,
When the start switch 104 is turned on at time t ₀ (see FIGS. 3 and 4), the R-S flip-flop 106 is set by the pulse signal P ₄ output in response to the turn-on. The high level signal from the output terminal Q is sent to the AND circuit 115,
116. At this time, one AND circuit 115 is given a low level signal from the set output terminal Q of the R-S flip-flop 107 which is in the reset state as described above, so its output remains a low level signal. Yes, but
On the other hand, the AND circuit 116 is supplied with a low level signal from the set output terminal Q of the R-S flip-flop 107, inverted to a high-level signal by an inverter 127, and is also supplied with the low level signal from the set output terminal Q of the R-S flip-flop 107, which is also in the reset state. Since a high level signal is applied from the reset output terminal, a high level signal is output from the AND circuit 116 and applied to the heater drive circuit 83. Therefore, the gate signal Sg is output from the heater drive circuit 83 to turn on the triax 14, and in response, the AC power supply 15 supplies electricity to the heater 6 via the pot switch 10 and the triax 14 to heat the pot 5. It became like this,
The rice cooking process is then started. As the rice cooking process progresses, the temperature of the pot 5 rises as shown in FIG. 3, and the temperature detection circuit 25 outputs a temperature detection signal Sd corresponding to the temperature of the pot 5. Then, when the temperature of the pot 5 rises to 70° C. stored in the first temperature value storage section 26 (time t ₁ ), the rice cooking amount detection means 130 starts to function. That is, in the rice cooking amount detection means 130, the comparison circuit 5
2 is a temperature detection signal input to its input terminal A.
A low level signal is output until time t ₁ when Sd becomes equal to the temperature value corresponding to "70°C" inputted from the first temperature value storage unit 26 to terminal B, and at that time t After ₁ , a high level signal is output. Further, the comparison circuit 53 detects the time t when the temperature detection signal Sd input to the terminal B becomes larger than the temperature value corresponding to "80°C" input from the second temperature value storage section 27 for the terminal A. A high level signal is output until time _t2 , and a low level signal is output after that time _t2 . Therefore, high level signals are output from both comparison circuits 52 and 53 only during the period from time _t1 to time _t2.
Since it is applied to the AND circuit 109, the pulse signal _P1 with a period of 1 second from the first frequency divider circuit 22 passes through the AND circuit 109 and is output to the counter 7 only during this period.
2 clock terminal CK is given. Therefore, as a result, the count value of the counter 72 is the time Ta required for the temperature of the pot 5 to rise from 70°C to 80°C.
(time from time t ₁ to t ₂ ).
However, the time Ta measured as above has the property of increasing or decreasing in proportion to the amount of rice cooked, and this time
The amount of cooked rice is determined based on the count value of the counter 72 corresponding to Ta. That is, the count value of the counter 72 is compared with each numerical value (corresponding to 2 minutes and 4 minutes) stored in the first and second time value storage sections 40 and 41 by comparison circuits 56 and 57, respectively.
At this time, the comparator circuit 56 outputs a low level signal when the count value of the counter 72 is smaller than the value equivalent to 2 minutes (in other words, when the amount of rice cooked is relatively small), and this low level signal is output from the ingarter 122.
The signal is inverted to a high level signal, which is a rice cooking amount signal, and is applied to line _L1 . Further, the comparison circuit 57
When the count value of the counter 72 is equal to or greater than the value equivalent to 4 minutes (in other words, when the amount of rice cooked is relatively large), a high level signal serving as a rice cooking amount signal is outputted to the line _L3 .
give to Furthermore, when the count value of the counter 72 is equal to or greater than the value equivalent to 2 minutes and smaller than the value equivalent to 4 minutes (in other words, when the amount of rice cooked is medium), a high level signal is output from the comparator circuit 56,
given to one input terminal of the AND circuit 112,
In addition, a low level signal is output from the comparator circuit 57, which is inverted to a high level signal by the inverter 123 and applied to the other input terminal of the AND circuit 112. As a result, the plain AND circuit 112 outputs a rice cooking amount signal. A high level signal is output and applied to line _L2 . In short, the rice cooking amount detection means 130 determines the amount of rice to be cooked based on the time required for the temperature of the pot 5 to rise from 70°C to 80°C, and a rice cooking amount signal (high level signal) indicating the determination result. is selectively output to lines L ₁ , L ₂ , and L ₃ . When the amount of cooked rice detected in this way is relatively small, the transfer gate 8 whose gate terminal is connected to line _L1
5, 89, and 95 are conductive, and when the detected rice cooking amount is medium, the transfer gates 86, 90, and 96, whose gate terminals are connected to line _L2 , are conductive, and the detected rice cooking amount is medium. If there are relatively many transfer gates, the transfer gates 87, 91, and 97 whose gate terminals are connected to the line _L3 become conductive. At this time, the transfer gates 89, 9 are selectively turned on as described above.
The temperature values stored in the seventh, eighth, and ninth temperature value storage units 32, 33, and 34 corresponding to This is to adjust the stored temperature value (ie 112℃), and each of these memorized temperature values is
It is selectively given to the input terminal Y of 8 according to the magnitude of the detected rice cooking amount, and in the adding circuit 68,
The temperature value input in this way is stored in the thirteenth temperature value storage unit 3.
The value is added to the value stored in 8 (heater power-off temperature Dz) and output. Also, transfer gates 95, 9 are selectively turned on as described above.
The time values stored in the fifth, sixth, and seventh time storage units 44, 45, and 46 corresponding to 6 and 97 correspond to the reheating operation reference period N (the time values stored in the 11th time value storage unit 50). time value, i.e., 30 seconds), and each of these stored time values is stored in the adder circuit 70.
is selectively given to the input terminal Y according to the magnitude of the detected rice cooking amount, and in the case of the adder circuit 70,
The time value input in this way is stored in the eleventh time value storage unit 5.
It is added to the value stored in 0 (reheating operation reference time N) and output.

Thereafter, when the temperature of the pot 5 further increases and reaches the lower limit temperature "90° C." stored in the third temperature value storage section 28 (time t ₃ ), each of the input terminals A and B of the comparator circuit 54 When the input values meet the relationship A≧B, the output of the comparison circuit 54 is inverted to a high level signal. As a result, the AND circuit 111 receives the high level signal at one input terminal.
allows the input to the other input terminal, that is, the pulse signal P ₂ with a period of 10 seconds from the second frequency divider circuit 23 to pass, and also the comparator circuit 5
The comparator circuit 65 which receives the high level signal from 4 at the enable terminal En via the delay circuit 80 becomes operational, and the boiling detection means 13 is activated depending on the iron.
1 boiling detection function is now enabled. That is, when the pulse signal P ₂ begins to pass through the AND circuit 111, the pulse signal P ₂ comes to be applied to the clock terminal φ of the shift register 81. The temperature detection signal Sd is read and stored every 10 seconds, and a new temperature detection signal is
Every time Sd is read, the old temperature detection signal Sd is sequentially shifted to the upper unit register. As a result, the 12th unit register 81b stores the temperature detection signal Sd 120 seconds (2 minutes) before the current temperature detection signal Sd, and the 18th unit register 81c stores the current temperature detection signal Sd. 180 from temperature detection signal Sd
The temperature detection signal Sd seconds (3 minutes) ago is memorized and
The 24th unit register 81d stores the temperature detection signal 240 seconds (4 minutes) before the current temperature detection signal Sd.
SD will be memorized. At this time, the data stored in the unit registers 81b, 81c, and 81d are stored in the corresponding transfer gates 85, 81d, and 81d, respectively.
The input terminal E of the subtraction circuit 66 via 86 and 87
However, as mentioned above, when the amount of cooked rice is relatively small, the transfer gate 85 is in a conductive state, and the data stored in the unit register 81b is transferred to the input terminal E of the subtraction circuit 66.
Similarly, when the amount of cooked rice is medium or relatively large, the unit register 81 is given to
Each stored data of c and 81d is applied to the input terminal E of the subtraction circuit 66. The temperature detection signal Sd is directly inputted to the other input terminal D of the subtraction circuit 66, so that the subtraction circuit 66 receives two minutes from the value indicated by the current temperature detection signal Sd. Temperature detection signal Sd before, 3 minutes ago, or 4 minutes ago
The subtraction result is a certain reference time (2 minutes, 3 minutes, or 4 minutes).
This value corresponds to the temperature rise value of the pot 5 within 1 minute), which in turn corresponds to the time-series temperature gradient of the pot 5. Therefore, the temperature of the pot 5, that is, the rate of increase of the temperature detection signal Sd is:
It has the property of becoming almost zero when the water in the pot 5 reaches a boiling state, and therefore detects that the temperature rise value of the pot 5 within the reference time has become below a predetermined comparative temperature value. Then, it can be determined whether or not the inside of the pot 5 has reached a boiling state. In this case, since the temperature increase rate of the pot 5 tends to be slower as the amount of rice cooked increases, in order to accurately detect boiling, it is desirable to change the above reference time according to the amount of rice cooked. Now, in order to perform accurate temperature detection, the reference time (i.e., the sampling time of the temperature detection signal Sd) is automatically changed to 2 minutes, 3 minutes, or 4 minutes as described above. That's what I do. Then, in the comparison circuit 65, the output from the subtraction circuit 66 (the temperature rise value of the pot 5 within the three-step reference time determined according to the amount of rice cooked) and the fifth temperature value storage section 30 are stored for comparison. The numerical value stored as the temperature value (equivalent to 2°C) is compared, and when the temperature rise value of the pot 5 within the above reference time is less than 2°C, a high level is output from the comparison circuit 65. A boiling detection signal Sz consisting of a signal is output (time t ₄ ).

Therefore, at the time _t4 , the memory circuit 8
2 is in an initialized state, the output of the subtraction circuit 67 that subtracts the numerical value (corresponding to 3° C.) stored in the sixth temperature value storage section 31 from the stored value is a negative value. Yes, the comparison circuit 60 is in a state of outputting a low level signal. For this reason, OR circuit 11
The comparator circuit 60 and R-
A low level signal is applied from the reset output terminal of the S flip-flop 106, and this low level signal is inverted to a high level signal by an inverter 126 and applied to one input terminal of the AND circuit 114. Therefore, when the boiling detection signal Sz (high level signal) is output as described above at time _t4 , a high level signal is output from the AND circuit 114 and the R-S flip-flop 107 is set. Then, the output of the AND circuit 116, which had been outputting a high level signal, is inverted to a low level signal, and the R-S flip-flops 106, 1 are connected to each input terminal of the AND circuit 115.
A high level signal is applied from each set output terminal Q of 07 and a reset output terminal of R-S flip-flop 108, and a high level signal is output from the AND circuit 115, and the heater output is controlled accordingly. A pulse-like control signal Sc with a duty ratio of 50% is output from the circuit 84 and supplied to the heater drive circuit 83. As a result, the triax 14 is turned on and off at a duty ratio of 50%, and since the rated output of the heater 6 is 600 watts, the heater 6 generates heat at an output of 300 watts, which is half the rated output. become. Further, when the R-S flip-flop 107 is set at the above-mentioned time _t4 , the trigger circuit 77 is driven and the trigger pulse _P3 is generated from now on.
is output, the counter 73 in the boiling time measuring means 132 is initialized by the trigger pulse P ₃ and the boiling time measuring means 132 becomes functional, and the transfer gate 88
becomes conductive, and the temperature detection signal Sd at time _t4 (corresponding to the temperature of the pot 5 at the time of detection of the boiling state) is stored in the memory circuit 82 in the power cutoff means 134. become. Also, at this point, there is still enough water left in the pot 5 and its temperature does not exceed 100°C, so the temperature detection signal Sd and the fourth temperature value corresponding to the temperature of the pot 5 are The comparator circuit 55 that compares the boiling end temperature (corresponding to 110°C) stored in the storage section 29 outputs a high level signal, and therefore the high level signal and the reset output terminal of the R-S flip-flop 108 The AND circuit 110 receiving the high level signal receives the pulse signal from the first frequency dividing circuit 22.
It is in a state where the passage of P ₁ (1 second period) is allowed. Therefore, the counter 73 initialized as described above
The count value indicates the elapsed time from time _t4 , that is, the duration of the boiling state. When the rice cooking process further progresses and the inside of the pot 5 reaches a so-called dry-up state, the temperature of the pot 5 will rise rapidly.
When the temperature of the comparator circuit 55 reaches 110° C. at time _t5 , the relationship between the input terminals A and B of the comparison circuit 55 becomes A<B, and the output is inverted to a low level signal. blocks the passage of the pulse signal _P1 , and the counting operation of the counter 73 is stopped. Therefore, as a result, counter 7
The count value 3 is from time t ₄ when the boiling detection signal Sz is output to time t ₅ when the temperature of the pot 5 reaches 110°C.
The boiling time measuring means 132 measures the boiling state duration Tb in this manner.

Boiling state duration Tb measured as above
Similar to the time Ta from time t ₁ to t ₂ described above, Ta has the property of increasing or decreasing in proportion to the amount of rice cooked, and also has the property of being influenced by the ratio of rice to water during cooking.
Based on such boiling state duration Tb, the amount of cooked rice detected by the amount of cooked rice detection means 130 is corrected as follows. That is, the count value of the counter 73 is calculated by the comparator circuits 58 and 59 into the respective numerical values (7 minutes, 7 minutes,
(equivalent to 9 minutes). At this time, the comparator circuit 58 outputs a low level signal when the count value of the counter 73 is smaller than the value equivalent to 7 minutes (in other words, when the amount of rice cooked is relatively small), and this low level signal is turned to a high level by the inverter 124. It is inverted to a level signal and applied to line _L4 . Furthermore, when the count value of the counter 73 is equal to or greater than the value equivalent to 9 minutes (in other words, when the amount of cooked rice is relatively large), the comparison circuit 59 outputs a high level signal and lines the line.
Give to L ₆ . When the count value of the counter 73 is equal to or greater than the value equivalent to 7 minutes and smaller than the value equivalent to 9 minutes (in other words, when the amount of rice cooked is medium),
A high level signal is output from the comparison circuit 58 and applied to one input terminal of the AND circuit 113, and a low level signal is output from the comparison circuit 59, which is inverted to a high level signal by the inverter 125 and applied to the AND circuit 113. is now applied to the other input terminal of
A high level signal is output from the AND circuit 113 and applied to line _L5 . When the amount of cooked rice detected in this way is relatively small, the transfer gates 92, 98, and 101 whose gate terminals are connected to line _L4 are in a conductive state, and when the amount of cooked rice detected is medium, The gate terminal is line
Transfer gates 93, 99, connected to L ₅
102 exhibits a conductive state and furthermore, when the detected amount of cooked rice is relatively large, transfer gates 94, 100, 10 whose gate terminals are connected to line L ₆
3 becomes conductive. At this time, the 10th, 11th, and 12th transfer gates correspond to the transfer gates 92, 93, and 94 that are selectively turned on as described above.
The temperature values stored in the temperature value storage units 35, 36, and 37 are also used to correct the heater power-off temperature Dz (the temperature value stored in the 13th temperature value storage unit 38, that is, 112°C). Each of these stored temperature values is selectively given to the input terminal Y of the adder circuit 69 depending on the length of the boiling state duration Tb, and the adder circuit 69 inputs the temperature input in this way. The value is further added to the numerical signal from the adding circuit 68 (i.e., the temperature value corresponding to the amount of cooked rice detected by the rice amount detection means 103 is added to the heater power-off temperature Dz), and the following is performed. This function acts to correct the added temperature value by the rice cooking amount detection means 103 and thus the detected rice cooking amount. Further, transfer gates 98, 99, which are also selectively turned on,
The time values stored in the 8th, 9th, and 10th time value storage units 47, 48, and 49 corresponding to 100 also correspond to the reheating operation reference time N (the time stored in the 11th time value storage unit 50). value, that is, 30 seconds), and each of these storage time values is added to the adder circuit 71.
is selectively applied to the input terminal Y of the boiling state according to the length of the boiling state duration Tb, and in the case of the adder circuit 71, the time value inputted in this manner is applied to the adder circuit 7.
Numerical signal from 0 (i.e., reheating operation reference time N
(to which a time value corresponding to the amount of cooked rice detected by the rice cooking amount detection means 130 is added)
is further added to the amount of rice cooked, thereby acting to correct the addition time value by the rice cooking amount detection means 130, and thus the detected rice cooking amount. In addition, in the case of the reheating control means 133, when the boiling state duration time Tb measured by the boiling time measuring means 132 is relatively short, the reheating control means 133 stores information in the twelfth time value storage section 51a according to the conduction of the transfer gate 101. When the stored unevenness time "15 minutes" is enabled and the boiling state duration time Tb is medium or relatively long, the
13. The irregular times "13 minutes" and "11 minutes" stored in the fourteenth time value storage units 51b and 51c are validated.

Now, at the subsequent time t ₆ , the temperature of the pot 5 becomes the cooked rice temperature corresponding to the output from the adding circuit 69 (i.e., the heater power-off temperature Dz (112°C)).
In contrast, the temperature value and boiling time measuring means 1 according to the amount of cooked rice detected by the amount of cooked rice detection means 130
32), the input values to the input terminals A and B of the comparator circuit 61 in the power cutoff means 134 become in the relationship A≧B, and the comparator circuit 61 outputs a high level signal. Since the signal is output, R-S flip-flop 108 is set. Then, R-S flip-flop 1
The low level signal from the reset output terminal of 08 is given to the AND circuit 115, and the AND circuit 1
15 is inverted to a low level signal, the heater output control circuit 84 is stopped, and in response, the heater drive circuit 83 stops outputting the gate signal Sg to keep the triac 14 in the turned-off state, that is, the heater output control circuit 84 stops driving. 6 is turned off, and the rice cooking process is completed. At this time, a high level signal from the set output terminal Q of the R-S flip-flop 108 is applied to the AND circuits 117 and 118, and the AND circuit 117 allows the pulse signal _P1 to pass. In response, the reheating control means 133 functions to shift to the uneven process. In short, the temperature of the pot 5 is determined by the temperature value (7th, 8th, 9th temperature value storage unit 32, 33, 34) and the corrected temperature value by the boiling time measuring means 132 (10th, 11th, 12th temperature value storage unit 35,
When the rice reaches the finished cooking temperature (one of the temperature values stored in 36 and 37), the rice cooking process is completed and the process moves to the uneven process. Describe the action in the process. In the case of this embodiment, the above-mentioned cooking temperature is stored in the seventh to thirteenth temperature value storage units 32 to 38.
The temperature varies between 114°C and 122°C depending on the stored contents.

The counter 75 in the reheating control means 133 has been counting the pulse signal P ₁ since the power was turned on, and therefore, at time t ₆ , the count value is at least equal to the numerical signal (main signal) output from the adding circuit 71 . In the case of the embodiment, the maximum value corresponding to 100 seconds) is larger, and as a result, the input terminal A of the comparator circuit 64,
Each input value for B is a function of A<B, and the comparator circuit 64 outputs a low level signal. Further, since the other counter 74 in the reheating control means 133 starts counting from time t6, the comparison circuit 62 starts counting at time _t6 .
The respective numerical values input to the input terminals A and B are a function of A≧B, and a high level signal is output from the comparator circuit 62. Then, when the heater 6 is cut off at time t ₆ , the temperature of the pot 5 once overshoots as shown in _FIG . is the first
When the temperature drops to the reheating operation start temperature Dr (103°C) stored in the temperature value storage unit 39 of 14, each input value to the input terminals A and B of the comparator circuit 63 becomes A≧B.
Since a high level signal is output as a function of
starts outputting a trigger pulse _P3 , and the counter 75 is initialized by the trigger pulse _P3 . Then, the input terminals A and B of the comparator circuit 64
Each input value becomes a function of A≧B, and a high level signal is output from the comparator circuit 64. In response, high level signals are given to all input terminals of the AND circuit 118, and the AND circuit The output of 118 is inverted to a high level signal. As a result, the heater drive circuit 83 that receives the high level signal from the AND circuit 118 turns on the triac 14 to re-energize the heater 6, and a reheating operation is performed accordingly. At this time, the count value of the counter 75 indicates the elapsed time from time _t7 when the temperature of the pot 5 decreased to 103°C, and at time _t8 , the count value corresponds to the output from the adder circuit 71. (i.e., the reference time for reheating operation N (30 seconds),
When the time value corresponding to the amount of cooked rice detected by the rice cooking amount detection means 130 and the time value corrected by the boiling time measurement means 132 is reached, each input value to the input terminals A and B of the comparison circuit 64 becomes A.
Since the output of the comparison circuit 64 is inverted to a low level signal as a function of <B, the AND circuit 11
The output of the heater 8 is also reversed and the heater drive circuit 83 turns off the triac 14, thereby cutting off the power to the heater 6 and stopping the reheating operation.
After this, at times t ₉ and t ₁₁ when the temperature of the pan 5 rises once due to the reheating operation and then decreases to 103°C, the heater 6 is reenergized and the reheating operation is performed in the same manner as described above. , such a reheating operation occurs at each time when the count value of the counter 7 corresponds to the output from the adder circuit 71.
It is stopped at T ₁₀ and t ₁₂ . Then, after time t ₆ , as mentioned above, the irregularity time (15 minutes, 13 minutes, 11 minutes) is activated according to the length of the boiling state duration Tb.
When the count value of the counter 74 exceeds the value corresponding to the above-mentioned irregularity time (indicated by Tc in FIG. ₄ ), the comparator circuit 62 outputs an output. is inverted to a low level signal, the state where the AND circuit 118 outputs the low level signal and the heater drive circuit 83 are maintained in a state where the operation is stopped, and the uneven process is completed. Then, when the output of the comparison circuit 62 is inverted to a low level signal as described above, the output of the inverter 128 is inverted to a high level signal and the trigger pulse _P3 is output from the trigger circuit 79. ₃ , the R-S flip-flop 106 is reset, and from then on, the process proceeds to a warming process using a warming heater (not shown). In summary, in the unevenness process, the temperature of the pot 5 is the temperature for starting the reheating operation.
When the temperature drops to 103°C, the heater 6 is energized again, and the energization time is a time corresponding to the amount of cooked rice detected by the rice amount detection means 130 with respect to the reference time N for reheating operation, which is 30 seconds. (any one of the time values stored in the fifth, sixth, and seventh time value storage units 44, 45, and 46) and the corrected time value (the eighth, ninth, and Ten
A control that repeats control in which the heater 6 is cut off and the reheating operation is terminated when the sum of the time values (any one of the time values stored in the time value storage units 47, 48, and 49) has been reached. In this embodiment, the reheating operation time ranges from 30 seconds to 30 seconds depending on the contents stored in the fifth to eleventh time value storage units 44 to 50.
Changed within 70 seconds. Further, the duration time Tc of the uneven stroke is shortened as the boiling state duration time Tb is longer.

So far, we have described the effect when the temperature of the pot 5 continues to rise without decreasing after the boiling detection signal Sz is output at time _t4 and the output of the heater 6 is reduced to half of the rated value. However, in the following, the effect when the temperature of the pot 5 decreases after the output of the heater 6 is reduced in this way will be explained using FIGS. 5 and 6, which are similar to FIGS. 3 and 4, respectively. This will be explained with reference to the figures. That is, the phenomenon in which the temperature of the pot 5 decreases when the output of the heater 6 is reduced by half occurs when the water in the pot 5 has not yet boiled (in other words, when the boiling detection signal Sz is erroneously output). Such a phenomenon can occur, for example, when seasonings such as soy sauce put into the pot 5 burn on the bottom of the pot 5 when making cooked rice, and this causes the contents of the pot 5 to burn. It is believed that this is caused by an increase in the gap between the temperature of the water and the temperature detected by the thermistor 9. Therefore, when the output of the heater 6 is halved at time _t4 in FIGS. 5 and 6, the temperature of the pot 5 at that time (i.e., the boiling detection means 131 is in the boiling state), as described above. The temperature detection signal Sd corresponding to the temperature of the pot 5 at the time when the temperature is detected is stored in the storage circuit 82 in the boiling detection compensating means 135. At this time, the subtraction circuit 67 in the boiling detection compensating means 135 subtracts the value stored in the sixth temperature value storage section 31 (corresponding to 3° C.) from the value stored in the storage circuit 82, and the subtraction result is temperature value corresponding to
Tp is applied to the input terminal A of the comparator circuit 60. Therefore, after that, the temperature of the pot 5 is set to the above temperature value.
When the voltage drops to Tp (time _t41 ), the output of the comparison circuit 60 is inverted to a high level signal, and in response to this, the R-S flip-flop 107 is reset and the trigger circuit 76 is driven to trigger its trigger. A trigger pulse P ₃ from circuit 76 initializes shift register 81 . Therefore, the output of the AND circuit 115 is inverted to a low level signal, and the output of the AND circuit 116 is inverted to a high level signal, so that a high level signal is continuously given to the heater drive circuit 83.
In response to this, the heater 6 begins to generate heat at its rated output, that is, an output of 600 watts. In addition, in response to the shift register 81 being initialized as described above, the boiling detection means 131 starts to perform the boiling state detection operation similar to that described above, and for example, at time _t42 , the boiling detection signal is output from the comparator circuit 65. When Sz is output, the output of the heater 6 is halved again. Further, if the temperature of the pot 5 decreases again after this, the same operation as described above is repeated, and in this way, the boiling detection auxiliary means 135 and the boiling detection means 131 can detect the boiling point more accurately. It works like this.

According to the present embodiment described above, the following effects can be achieved. That is, the time period during which the inside of the pot 5 is in a boiling state, that is, the boiling state duration time Tb, is measured, and the longer the boiling state duration time Tb is, the longer the unevenness process duration time Tc is shortened, so that the amount of rice cooked can be reduced. Unlike conventional methods, the time required to make rice alpha-alpha is insufficient when the amount of rice is small, or unnecessary unevenness processes are not performed when there is a large amount of rice to be cooked. As a result, the unevenness process can be automatically adjusted to be carried out for a necessary and sufficient amount of time depending on the amount of rice to be cooked. In addition, the boiling state of the water in the pot 5 is not detected based on a predetermined absolute upper limit temperature, but when the water in the pot 5 exhibits a boiling state, the temperature gradient of the pot 5 is detected. that the gradient is below a certain value (specifically, the amount of change in the temperature of the pot 5 within a predetermined reference time is a certain comparison temperature value (2°C) stored in the fifth temperature value storage unit 30; Since the configuration detects based on the following), the contact state between the heat-sensitive cap 7 and the bottom of the pot 5, the thermistor 9 constituting the temperature detection means 25, or the circuit of the A-D converter 24. Even if there are variations in constants and changes in their characteristics over time, changes in atmospheric pressure, or fluctuations in the boiling point due to seasonings being added to the pot 5 when making cooked rice, the water in the pot 5 It is possible to accurately detect the boiling state of water. When detecting a boiling state in this way, there is a risk that boiling detection as described above may become inaccurate when the amount of cooked rice differs because the temperature increase gradient of the pot 5 changes depending on the amount of cooked rice. However, in this embodiment, the temperature gradient of the pot 5, which is the target at the time of boiling detection, is changed depending on the magnitude of the amount of cooked rice detected by the amount of cooked rice detection means 130 (specifically, when measuring the temperature gradient) By changing the reference time required for the cooking process), the boiling state of the water in the pot 5 can always be accurately detected even when the amount of rice to be cooked differs. And, in this example,
The rice cooking control is configured such that the heater 6 generates heat at its rated output until the boiling state is detected, and then the output of the heater 6 is halved, but in this case, as described above, the boiling state cannot be detected accurately. Because of this, the rice cooking control described above can be performed strictly.
As a result, it is possible to fully satisfy the so-called "medium-sized" condition, which is one of the conditions for cooking rice deliciously, and the rice can be cooked with less stickiness, and the rice is generally well-cooked. It can be done. Furthermore, in this embodiment, the larger the amount of cooked rice detected by the rice cooking amount detecting means 130, in other words, the longer a relatively large amount of unnecessary moisture remains in the pot 5 during dry-up, the more the heater 6 is cut off. That is, since the temperature at which the rice is cooked is raised, the rice can be cooked well from this aspect as well. Moreover, in this case, the temperature at which the rice is cooked is corrected depending on the duration Tb of the boiling state in the pot 5 (that is, the period that varies depending on the amount of rice cooked and other factors), so the temperature at which the rice is cooked is corrected depending on the amount of rice cooked. as well as,
Rice cooking can be controlled more precisely according to the ratio of rice and water during rice cooking. Further, the reheating operation time during the uneven stroke, in other words, the average output of the heater 6 during the uneven stroke is also detected by the rice cooking amount detection means 130, and the boiling state duration time Tb
Since the time is changed according to the amount of rice to be cooked based on the amount of rice to be cooked, it is possible to alpha the rice as much as necessary, and when making cooked rice, the amount of soy sauce etc. put in the pot 5 can be changed. Since the boiling detection compensation means 135 compensates for errors in boiling detection caused by seasonings burning, etc., the boiling detection compensating means 135 can prevent the temperature inside the pot 5 from falling into a special state as described above. Even if there is a difference between the temperature detected by the detection means 25 and the actual temperature inside the pot 5, the boiling state of the water in the pot 5 can be detected very accurately. Furthermore, in each of the above embodiments, the function of the boiling detection means 131 is enabled only when the temperature of the pot 5 reaches the lower limit temperature (90° C.) stored in the third temperature value storage section 28. Therefore, there is no possibility that a period when the temperature gradient is flat, such as when the temperature of the pot 5 rises as indicated by G in FIG. 3, will be mistakenly detected as a boiling state.

In addition, in the above embodiment, the temperature of the pot 5 ranges from 70°C to 80°C.
Although the rice cooking amount detecting means 130 is configured to detect the rice cooking amount based on the time required for the temperature to rise to ℃, the temperature value for detection, that is, the first and second
The stored values of the temperature value storage units 26 and 27 are not limited to these, and may also be used for rice cooking with other configurations, such as one in which the amount of cooked rice is detected by measuring the entire weight of the pot 5. A quantity detection means may also be provided. Of course, each of the other temperature value storage units 28 to 39, 136 to 138 and each time value storage unit 40
The stored contents of 50 to 51a to 51c are not limited to the above-mentioned embodiments. In particular, the numerical values stored in the 14th temperature value storage section 39 for controlling the reheating operation are stored in the storage circuit 82. It may be substituted by the numerical value given. Further, in the above embodiment, the temperature increase value of the pot 5 within the reference time is 2.
The configuration is such that boiling is detected by outputting the boiling detection signal Sz when the temperature drops below ℃.
It is also possible to adopt a configuration in which boiling is detected based on the time required for the temperature to rise to a certain level exceeds a predetermined value. Furthermore, in the above embodiment, the boiling state duration time Tb is measured by the boiling time measuring means 132 based on the boiling end temperature (110° C.) stored in the fourth temperature value storage section 29. Instead, the point in time when the temperature of the pot 5 suddenly rises may be detected, and the boiling duration time may be measured based on the detection result.
Further, in each of the above embodiments, the rice cooking amount detected by the rice cooking amount detecting means 130 is ranked in three stages, but this may be further ranked in more stages. The configurations of the means 131 and the boiling time measuring means 132 are also changed accordingly, but by configuring them in this way, boiling detection can be performed more precisely. In the above embodiment, the average output of the heater 6 during the reheating operation is changed by time control, but other configurations may be used as long as the average power of the heater 6 is changed. The energization time of the heater 6 does not need to be constant each time as in the above-mentioned embodiments, and may be made to become shorter sequentially during each reheating operation, for example. In addition, instead of the heater output control circuit 84, a circuit configured to reduce the output of the heater 6 using a phase control method may be adopted, and instead of the triax 14, another switching element such as a relay may be used. You can also do it. Further, in the above embodiment, only the normal rice cooking operation is described, but it goes without saying that other rice cooking functions such as porridge cooking and brown rice cooking may be added in addition to this.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications without departing from the spirit thereof.

[Effects of the Invention] According to the present invention, as is clear from the above explanation, the shading process including the reheating operation is automatically adjusted to be performed for a necessary and sufficient time depending on the amount of rice cooked. As a result, the rice in the pot can be alpha-ized at all times, regardless of the amount of rice cooked, and delicious rice can be obtained, and the shading process can be unnecessarily prolonged. This has the excellent effect of eliminating waste of power and time.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention. Fig. 1 is a block diagram of the electrical configuration, Fig. 2 is a partially cutaway side view of the rice cooker, and Fig. 3 shows the pot temperature and heater output. FIG. 4 is a timing chart showing the output waveforms of each part in FIG. 1, FIG. 5 is a change characteristic diagram of pan temperature and heater output in a state different from that shown in FIG. 3, and FIG. 4 is a timing chart showing output waveforms of each part in FIG. 1 in a state different from that in FIG. 4; In the figure, 1 is the rice cooker body, 5 is a pot, 6 is a heater (heating means), 7 is a thermal cap, 9 is a thermistor, 10 is a pot switch, 13 is a control circuit, 25 is a temperature detection means, and 83 is a heater drive circuit, 84 is a heater output control circuit, 104 is a start switch,
106 is a stop switch, 129 is a clock means,
Reference numeral 130 indicates a rice cooking amount detection means, 131 a boiling detection means, 132 a boiling time measurement means, 133 a reheating control means, 134 a power cutoff means, and 135 a boiling detection compensation means.

Claims (1)

[Claims] 1. A device that is equipped with a pot that stores rice and water, a heating means that heats the pot, a temperature detection device that outputs a temperature detection signal according to the temperature inside the pot, and a temperature detection device that outputs a temperature detection signal according to the temperature inside the pot. A power cutoff means for cutting off power to the heating means when the level reaches a set cooking temperature; In an electric rice cooker equipped with a reheating control means that executes an uneven process that includes a reheating operation of energizing, the longer the duration of the boiling state of water in the pot during the rice cooking operation, the longer the reheating control is performed. A method of controlling an electric rice cooker, characterized in that the control method is performed so that the execution time of the uneven process by the means is shortened.