JPH0322162B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a soaking operation in which the pot heating means is temporarily cut off at the beginning of the rice cooking operation or the state in which the pot heating means is heated is maintained for a predetermined period of time. The present invention relates to a rice cooker configured to perform the rice cooking operation, and particularly relates to a rice cooker equipped with a timer means that can arbitrarily set the start time of the rice cooking operation.

[Technical Background of the Invention] In order to cook rice deliciously, it is necessary for the rice to absorb sufficient moisture.
Conventionally, at the beginning of the rice cooking operation, a soaking operation is performed in which the pot heating means, such as a rice cooker heater, is once turned off for a predetermined period of time, and the water temperature in the pot is then left for a predetermined period of time. A rice cooker is provided that allows the rice in the pot to actively absorb water during this soaking period. On the other hand, in such a rice cooker, a timer (for example, 12 hours) is provided so that the rice cooking operation starts at a desired time, and the rice cooking operation is started only when the timer operation time of this timer has elapsed. There is something configured like this.

[Problems with Background Art] Generally, when rice is soaked in water at room temperature, the amount of water absorbed by the rice is saturated in about 2 hours. However, in the rice cooker with the conventional configuration, the soaking operation is always performed after the rice cooking operation starts, regardless of the length of the timer operation time (i.e., the time the rice is left soaked in water before the rice cooking operation starts). Therefore, if the timer operation time is long, unnecessary soaking operations are performed, which unnecessarily increases the time required for cooking rice.Also, the number of times the heater is cut off for soaking operations becomes unnecessary. Another drawback is that the life of the contact circuit for power interruption is shortened.

[Object of the Invention] Therefore, the object of the present invention is to perform a soaking operation in which power is cut off to the pot heating means at the beginning of the rice cooking operation or the state in which the amount of heating by the pot heating means is reduced is maintained for a predetermined period of time when this is necessary. Since the rice cooking time can be executed automatically, there is no need to worry about the time required for cooking rice being increased, and the lifespan of the contact circuit can be extended, further shortening the time required for cooking rice. It is an object of the present invention to provide a rice cooker that also exhibits the effects that can be achieved.

[Summary of the Invention] The present invention is provided with a timer means that can arbitrarily set the start time of the rice cooking operation, and in which the power to the pot heating means is temporarily cut off or the amount of heating by the pot heating means is reduced at the beginning of the rice cooking operation. In a rice cooker that performs a soaking operation to maintain a state for a predetermined period of time, the rice cooker is controlled to perform a rice cooking operation without performing the soaking operation when the timer operation time of the timer means exceeds a predetermined time. It has the following characteristics.

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

In Fig. 1, 1 is the main body of the rice cooker consisting of an inner case 2 and an outer case 3, 4 is a lid, 5 is a pot housed in the inner case 2, and 6 is a space between the bottoms of the inner case 2 and the pot 5. This is a heater that is a pot heating means arranged in the space. Reference numeral 7 denotes a cup-shaped heat-sensitive part that is provided to be elastically pressed against the outer bottom of the pot 5, and a thermistor 8 serving as a temperature sensor is sealed inside the heat-sensitive part 7 by a heat-conductive molded member 9. It is configured so that the temperature of the pot 5 can be sensed by a thermistor 8.

Reference numeral 10 denotes a case disposed at the outer bottom of the rice cooker main body 1, and a control circuit 11, a display control circuit 12, and a timer circuit 13 as timer means are housed inside the case, the circuit configuration of which is shown in FIG. . Also, 1
Reference numeral 4 denotes a digital time display section disposed on the outer surface of the outer case 3, which has, for example, four 7-segment light emitting diodes 15a to 15d in a row, and displays the remaining timer time of the timer circuit 13. indicate.

Next, in FIG. 2, reference numeral 16 is an AC power source, and the heater 6 is connected between both terminals of the AC power source via a normally open relay switch 17. 18 is a drive circuit that turns on the relay switch 17 only when the signal "1" is input; 19 is a start switch for starting rice cooking; when the start switch 19 is turned on, a signal " ₁ " is sent to the line L1; ”
is output. Further, 20 is an auxiliary drive circuit which turns on the start switch 19 only when a signal "1" is input. 21 is a pulse generator, which consists of a shaping circuit 22 that shapes the waveform of the output of the AC power supply 16 and a frequency dividing circuit 23 that divides the frequency of the output of this shaping circuit 22;
is configured to output a clock pulse Pc to an input line _L2 at a period of, for example, one second, and output a clock pulse P'c to a line _L3 at a period of, for example, one minute.

Reference numeral 24 denotes an A-D converter which receives the resistance value of the thermistor 8 as an input, and converts the input value into a digital signal every time a clock pulse Pc is received from the line _L2 at its terminal φ. A temperature converter 25 constitutes the temperature measuring section 26 together with the thermistor 8 and the A-D converter 24, and this converts the output of the A-D converter 24 into a digital temperature value every time a clock pulse Pc is received at its terminal φ. The digital temperature value is converted and outputted to line _L4 as a temperature value signal Sd corresponding to the temperature of the pot 5 sensed by the thermistor 8.

Now, in the following, the control circuit 11, display control circuit 12, and timer circuit 13 will be explained in terms of hardware using logic circuits and functional blocks. Of course, the same function as the timer circuit 13 may be obtained.

First, an overview of each functional block of the control circuit 11 will be explained.

27 is a calculation unit that receives the temperature value signal Sd at the input terminal 1, and this calculates when the temperature gradient of the pot 5 corresponding to the temperature value signal Sd starts to rise from a flat state (the state where the water in the pot 5 is boiling). At the same time, the output of the output terminal _P0 is reversed from the previous signal "0" to the signal "1", and the finished cooking temperature value is determined based on the temperature value signal Sd when the temperature gradient of the pot 5 starts to rise. D ₁ and temperature value for cooking D ₂ (However,
D ₁ > D ₂ ) are output from output terminals P ₁ and P ₂ respectively,
Furthermore, when the temperature of the pot 5 corresponding to the temperature value signal Sd becomes, for example, 40° C. or higher before this, the output of the output terminal P ₃ is inverted from the signal “0” to the signal “1”.

28 is a counter that counts the pulses input to the clock input terminal CK, and this is the clear terminal.
Cleared when signal "1" is input to CL. Comparing units 29 to 33 output a signal "1" when the input value of the terminal A is greater than or equal to the input value of the terminal B, and output a signal "0" in other cases. Reference numeral 34 denotes a double-cooking storage section, in which a double-cooking time value T ₃₄ (for example, 900 (seconds) in this embodiment) is stored.

Reference numerals 35 and 36 are storage units for soaking, and one storage unit 35 stores a soaking time value T ₃₅ (for example, 60 (minutes) in this embodiment), and the other storage unit 36
The numerical value "0" is stored in . Reference numeral 37 denotes a timer time determination storage section which constitutes the determination section 38 together with the comparison section 33, and this storage section stores the determination time value T ₃₇
(For example, 3 (hour)) is stored. A down counter 39 counts the pulses input to the clock input terminal CK, and is preset to the input value for the terminal T when a signal "1" is input to the terminal W. Further, 40 is an R-S flip-flop, 41 to 46 are AND circuits, 46 to 48 are OR circuits, and 49 to 51 are NOT circuits.

Next, an overview of each functional block of the display control circuit 12 will be explained.

52 to 55 are the light emitting diodes 15a, respectively.
These are drivers for driving 15d to 15d, and when a numerical signal is received at the terminal N, these drivers cause the corresponding light emitting diode to display a number according to the numerical signal. Also, 56 is a NOT circuit, 57 to 6
0 is a transfer gate, and these transfer gates 57 to 60 exhibit a low impedance and allow the signal to pass only when a signal "1" is input to their gate terminals.

On the other hand, an outline of each functional block of the timer circuit 13 is as follows.

61 is a count section, which is composed of a hexadecimal counter corresponding to the "hour" element and a sexagesimal counter corresponding to the "minute" element.The hexadecimal counter receives the pulses input to the clock input terminal _CK1 . The sexagesimal counter counts the pulses input to the clock input terminal _CK2 .

Reference numeral 62 denotes a down-count section to which the count contents of the count section 61 are transferred and preset into a hexadecimal down counter and a sexagesimal down counter, respectively.Output terminals _P1 and _P2 of this are respectively used to count the counts of the hexadecimal down counter. The output terminals P ₃ and P ₄ correspond to the upper digits and lower digits of the count contents of the sexagesimal down counter, respectively.

The above sexagesimal down counter uses the clock pulse P'c (1 minute cycle) input to the clock input terminal CK.
The hexadecimal down counter is 60
Count the carry signal of the forward down counter. Further, the down-counting section 62 outputs a numerical signal " ₀ " from the output terminal P0 when the count contents of the hexadecimal down counter and the sexagenical down counter both reach zero.
In other cases, a numerical signal other than "0" is output from the output terminal _P0 . Furthermore, the down-counting section 62 has an output terminal _P5 that outputs a numerical signal corresponding to the elapsed time of the timer operation of the timer circuit 13, and a count signal is output from the output terminal _P5 every hour after the start of counting. "1", "2",
Gradually advance to "3", etc.

Reference numeral 63 denotes a comparison section which outputs a signal "1" only when the inputs to terminals A and B become equal. Reference numeral 64 is a timer storage section in which a numerical value "0" is stored. 65 and 66 are switches for setting timer time, and when these are turned on, a signal "1" is output to the corresponding lines _L5 and _L6 , respectively. Also, 67 and 68 are AND
It is a circuit.

Next, the specific signal flow shown in FIG. 2 will be described with reference to its effect and the temporal change characteristic diagram of the temperature of the pot 5 shown in FIG. 3. Now, for example, if you want to start cooking after 2 hours, use pot 5.
With a predetermined amount of rice and water stored in the container, the timer time of the timer circuit 13 is set using the switches 65 and 66. That is, when the switch 65 is turned on, the AND circuit 67 allows the passage of the clock pulse Pc, and the counting of the hexadecimal counter in the counting section 61 progresses.

Then, the count contents are displayed in the down count section 62.
is transferred to the output terminal of the down count section 62.
The count contents of the hexadecimal counter are output from _P1 and _P2 . In this state, the down count section 62
Since a numerical signal other than "0" is output from the output terminal P _{0 of} , and this numerical signal is given to the terminal A of the comparator 63, the comparator 63 inputs the input to the terminal A and the input to the terminal B. (the numerical value "0" stored in the timer storage unit 64) is inconsistent and outputs the signal "0", and this signal "0"
is inverted to a signal "1" by NOT circuit 56 and then applied to the gate terminals of transfer gates 57 to 60, allowing the signal to pass through.

Therefore, the output terminal P ₁ of the down count section 62,
The output from _P2 (corresponding to the count value of the hexadecimal counter in the counting section 61) is transferred to the transfer gate 57,
58 and is applied to the terminals N of the drivers 52 and 53, and the numbers "1" and "2" corresponding to the time are sequentially displayed on the light emitting diodes 15a and 15b, so that the display becomes "2". ”, if you release the on operation of the switch 65, the hexadecimal down counter in the down count section 62 will read “2”.
is preset, and the timer time of the timer circuit 13 is set to two hours.

Incidentally, when setting the timer time of the timer circuit 13 in minutes, the switch 6 may be turned on. When the timer time of the timer circuit 13 is set in this way, the down-counter 62 starts counting the clock pulses P'c with a period of one minute, and the clock pulses P'c are counted from the output terminals _P1 to _P4 . As a result, the display content of the time display section 14 (remaining timer time of the timer circuit 13) gradually decreases every minute.

Thereafter, when the timer operation of the timer circuit 13 ends at time _t0 in FIG. When the display content of the display unit 14 reaches 0:00, a numerical signal “0” is output from the output terminal P ₀ of the down count unit 62.
is output, the inputs to the terminals A and B of the comparator 63 match, and the signal "1" is output from the comparator 63.
is output.

In addition, when the timer operation of the timer circuit 13 is performed for two hours in this way, the down-counter 62 outputs the numerical signal "2" from its output terminal _P5 , so this numerical signal "2" The comparator 33 which has received at its terminal A and the determination time value T ₃₇ (3 (hours)) from the timer time determination storage section 37 at its terminal B outputs a signal "0".

Then, when the signal "1" is output from the comparator 63 as described above at time _t0 , the auxiliary drive circuit 20 that has received the signal "1" turns on the start switch 19, so that a signal is sent to the line _L1. "1" is now output, and the counter 28 is cleared by this signal "1", and the down count 39 is set to the immersion time value T ₃₀ (60 (minutes), which is the input value to the terminal T. )), and
At the same time, the R-S flip-flop 40 which receives the above signal "1" at its set input terminal S via the OR circuit 46 is set, and the signal "1" from its output terminal Q is applied to one input terminal of the AND circuit 44. given to.

At this point, the signal “0” from the output terminal P ₃ of the arithmetic unit 27 is inverted to a signal “1” by the NOT circuit 50 and then applied to the other input terminal of the AND circuit 44 via the OR circuit 48. As a result, a signal "1" is output from the AND circuit 44 and is applied to the drive circuit 18. Therefore, the relay switch 17 is turned on by the drive circuit 18, and the heater 6 is energized from the AC power source 16, and the pot 5 is heated by the heater 6 and the rice cooking operation is started. .

By heating the pot 5 in this way, its temperature reaches 40℃.
When it reaches (time t ₁ in FIG. 3), the signal "1" is output from the output terminal P ₃ of the arithmetic unit 27.
When the NOT circuit 50 outputs a signal "0", the output of the AND circuit 44 is inverted to a signal "0", and the drive circuit 18 turns off the relay switch 17 to cut off the power to the heater 6.

In this way, a soaking operation is performed in which the rice cooking operation is interrupted and the water temperature in the pot 5 is left in a high state, so that the rice in the pot 5 actively absorbs water during this soaking operation period. become. Further, when the signal "1" is output from the output terminal _P3 of the calculation unit 27 at time _t1 , the signal "1" is applied to the second input terminal of the AND circuit 45, and at this point, the signal "1" is applied to the second input terminal of the AND circuit 45.
The signal “0” from the comparator 32 is input to the first input terminal of the AND circuit 45, and the signal “1” is output by the NOT circuit 51.
Since it is given inverted, AND circuit 4
5 allows the passage of the clock pulse P'c (1 minute period) applied to its third input terminal,
The down counter 39 starts counting from its preset value "60".

After this, when the count value of the down counter 39 becomes "0" at time _t2 , the count value "0" is transferred to the terminal A.
In order to invert the comparator 32 which receives the numerical value “0” from the immersion storage unit 36 to the terminal B and outputs the signal “1”, this signal “1” is received via the OR circuit 48. The AND circuit 44 outputs the signal "1" again, and as a result, the power supply to the heater 6 is restarted, and the soaking operation is shifted to the rice cooking operation.

If the temperature of the pot 5 falls below 40°C during the dipping operation, the signal "0" is output from the output terminal _P3 of the calculation section 27, so the counting operation of the down count 39 is stopped midway. The soaking operation is temporarily interrupted, but when the temperature of the pot 5 exceeds 40° C. due to the rice cooking operation accompanying this interruption, the soaking operation is resumed.

While the soaking operation and rice cooking operation are being performed as described above, the temperature of the pot 5 rises as shown in FIG. It is output at the period of clock pulse Pc). When the water in the pot 5 is boiling, the temperature gradient in the pot 5 becomes flat, but at time _t3 in FIG.
When the temperature reaches DS°C and the temperature gradient starts to rise rapidly from a flat state, the calculation unit 27
outputs a signal “1” from its output terminal P ₀ ,
The finished cooking temperature D ₁ and the double cooking temperature value D ₂ corresponding to the temperature DS are outputted from the output terminals P ₁ and P ₂ , respectively.

Then, the signal “1” is output from the output terminal P ₀ .
is applied to each input terminal of the AND circuits 41, 42, and 43, the AND circuit 43 allows the passage of the clock pulse Pc applied to the other input terminal, and the counter 28 starts counting. On the other hand, the cooked temperature value D ₁ outputted from the output terminal P ₁ is converted into a temperature value signal by the comparator 30.
When the temperature value signal Sd exceeds the cooked temperature value _D1 at time _t4 , the comparison section 30 outputs a signal "1" and the AND circuit 4
is applied to one input terminal of 2.

At this time, since the signal "1" is given to the other input terminal of the AND circuit 42 from the output terminal P ₀ of the calculation section 27, the AND circuit 42 receives the signal "1".
This signal "1" is applied to the reset input terminal R of the R-S flip-flop 40 via the OR circuit 47. Therefore, the R-S flip-flop 40 is reset and the supply of the signal "1" to the drive circuit 18 is stopped, so the relay switch 17 is turned off and the heater 6 is cut off, and after this, the double cooking operation ( (uneven movement).

When the operation is shifted to the double-cooking operation in this way, the calculation section 2
The double-cooking temperature value D ₂ outputted from the output terminal P ₂ of 7 is compared with the temperature value signal Sd in the comparing section 29,
As the temperature of the pot 5 decreases due to the power outage of the heater 6, the temperature value signal Sd changes to the double-cooking temperature value _D2 at time _t5 .
When it becomes equal to , a signal "1" is output from the comparator 29 and applied to the second input terminal of the three-input type AND circuit 41. At this time, the AND circuit 41
Since the signal "1" is given to the first and third input terminals from the output terminal _P0 of the calculation section 27 and the comparison section 31, respectively, the AND circuit 41 outputs the signal "1", and this signal “1” is passed through the OR circuit 46 to the set input terminal S of the R-S flip-flop 40.
given to.

Therefore, the R-S flip-flop 40 is set and the signal "1" is again given to the drive circuit 18, so the relay switch 17 is turned on and the heater 6 is energized again, so that the pot 5 is reheated. The rice is cooked twice. After this,
When the temperature value signal Sd exceeds the cooked temperature value _D1 in accordance with the temperature rise of the pot 5 due to the double cooking, the heater 6 is cut off in the same manner as described above,
When the temperature value signal Sd becomes equal to the double-cooking temperature value _D2 in response to a decrease in the temperature of the pot 5 due to the power cutoff, the heater 6 is energized in the same manner as described above, and this operation is repeated.

Then, at time t ₆ , when 900 seconds (that is, 15 minutes) corresponding to the double-cooking time value T ₃₄ have elapsed from time t ₃ , the count value of the counter 28 changes to the double-cooking storage unit 3.
Since this becomes equal to the double-cooking time value T ₃₄ stored in No. 4, the comparator 31 outputs a signal "0". Then, the above signal “0” is output to NOT circuit 4.
After the signal is inverted to “1” by 9, the OR circuit 4
7 to the reset input terminal R of the R-S flip-flop 40 to reset the R-S flip-flop 40, thereby completing the double-cooking operation and completing the cooking of the rice in the pot 5.

On the other hand, if the timer operation time of the timer circuit 13 is set to a fixed time of 3 hours or more, the third
When the timer operation of the timer circuit 13 ends at time t ₀ in the figure, the output terminal of the down count section 62
Since the numerical signal from P ₅ is "3" or more, the comparing section 33 in the determining section 38 outputs a signal "1". That is, the determination unit 38 outputs a signal "1" as a determination signal when the timer operation time of the timer circuit 13 exceeds the fixed time of 3 hours.
This signal "1" is input to the AND circuit 44 via the OR circuit 48. Therefore, even when the signal "1" is output from the output terminal D ₀ of the arithmetic unit 27 at the subsequent time t ₁ and the output of the NOT circuit 50 is inverted to the signal "0", the output from the AND circuit 44 to the drive circuit 18 is
Since the signal “1” is continuously given to
As a result, the rice cooking operation is continuously performed without the soaking operation being performed.

That is, if the timer operation time of the timer circuit 13 is longer than 3 hours, in other words, if the rice cooking operation is started with the rice in the pot 5 having sufficiently absorbed water, the timer circuit 13 will continue to operate for at least 60 minutes. This eliminates the need for unnecessary soaking operations, thereby shortening the time required for cooking rice, and reducing unnecessary opening and closing of the relay switch 17, thereby extending its lifespan.

It should be noted that during the dipping operation, it is not necessary to cut off the power to the heater, and it is of course possible to simply reduce the output by energizing the heater through a diode, for example.

[Effects of the Invention] According to the present invention, as is clear from the above explanation, the power to the pot heating means is temporarily cut off at the beginning of the rice cooking operation, or the state in which the amount of heating by the pot heating means is reduced is maintained for a predetermined period of time. The soaking operation can be automatically performed only when necessary, eliminating the risk of unnecessarily lengthening the time required for cooking rice, and prolonging the life of the contact circuit. Furthermore, it can also have the effect of further shortening the time required for cooking rice.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; Fig. 1 is a partially cutaway side view of the rice cooker, Fig. 2 is a block diagram showing the electrical configuration, and Fig. 3 shows the temperature change state of the pot. FIG. In the figure, 5 is a pot, 6 is a heater (pot heating means), 8
is a thermistor (temperature sensor), 11 is a control circuit,
13 is a timer circuit (timer means), and 38 is a determination section.

Claims (1)

[Claims] 1. A control circuit that performs a dipping operation in which the pot heating means is temporarily cut off or the heating amount by the pot heating means is reduced for a predetermined period of time at the beginning of the rice cooking operation, and a timer operation that can be set arbitrarily. Therefore, a rice cooker is provided with a timer means for performing a rice cooking operation, and is controlled so that the rice cooking operation is performed without performing the soaking operation when the timer operation time exceeds a certain time.