JPS63145612A - Rice cooker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a rice cooker that performs a rice cooking process and a steaming process.

(Prior art) Conventionally, this type of rice cooker has been equipped with a heater drive control means that controls on/off of the heater and heater output, a temperature detection device that detects the temperature of the pot, and a temperature detection device that uses the temperature detection device. boiling detection means for detecting a boiling state based on the temperature detection device; and dry-up detection means for detecting a dry-up state based on temperature detection by the temperature detection device;
Based on temperature detection by the temperature detection device, boiling detection by the boiling detection means, dry-up detection by the dry-up detection means, etc., the heater is drive-controlled by the heater drive control means to execute the rice cooking process and the steaming process. There is. Specific examples thereof are shown in FIGS. 9 and 10. In this case, a soaking process is provided before the rice cooking process. As shown in FIGS. 9 and 10, the rice-cooking process is performed by heating the pot 2 by turning the heater 1 on and off at its high output H (W), and the rice-cooking process 1 is first turned on at high output H, and when the temperature detected by the temperature detection device equipped with the temperature sensor 3 that detects the temperature of the pot 2 is detected as reaching the boiling temperature by the boiling detection means (time tx). , the output of the heater 1 is reduced to approximately half the output M (W), and then the inside of the pot 2 is in a dry-up (cooked) state based on the temperature detected by the temperature detection device (temperature rise range from boiling temperature). When this is detected (time tz), the heater 1 is automatically turned off to complete the rice cooking process, and thereafter, the heater 1 is turned on and off as appropriate to execute the uniform process. This shading step is carried out for a time (for example, 15 minutes) necessary to gelatinize the rice, which is already at boiling temperature.

By the way, in conventional rice cookers of this type, due to the heating structure mainly consisting of the heater 1, the degree of temperature change of the rice during the rice cooking process is limited to the A part (the part near the inner surface of the pot 1) and the B part (the part near the inner surface of the pot 1) shown in FIG. (inward part from part A).

The curves a, b, and c in FIG. 10 differ in the C portion (further inward central portion), and in particular, it takes a considerable amount of time to reach the boiling temperature in the C portion.

As a result, even if the rice in the C part moves to the steaming process without reaching the boiling temperature state and reaches the boiling temperature state in this steaming process, the time until the end of the steaming process, that is, boiling The time required to maintain the temperature state is short, and the time necessary for gelatinizing the rice is insufficient, resulting in a problem that hard rice remains at the end of the shading process.

In order to solve this problem, it is conceivable to set the execution time of the unevenness process to be longer, but since this unevenness process is executed after dry-up is detected, the inside of the pot is almost in an anhydrous state. However, since the conduction of heat from the heater to the rice is facilitated by water acting as a heat medium, in such an anhydrous state, heat conduction due to the movement of water as a heat medium cannot be expected. It takes a considerable amount of time for the rice in the C part to reach the boiling temperature state, and if it takes a long time to maintain the boiling state after reaching the boiling temperature state, which is necessary for the gelatinization of the rear bed, the rice in the sloping process will be delayed. Execution time becomes extremely long.

(Problem to be Solved by the Invention) As described above, in the rice cooking process, in the rice cooking process, when the heater is kept on from the time when the boiling state is detected until the dry-up state is detected, a part of the rice in the pot reaches the boiling temperature state. There is a problem in which the rice goes to the uneven cooking stage without being cooked properly, causing rice to be cooked unevenly, with hard rice remaining in some parts.As a countermeasure,
In the case where the time of the varnishing process is changed, it is necessary to make the execution time of the varnishing process extremely long, resulting in a problem that the rice cooking time becomes longer.

The present invention has been made in view of the above circumstances,
The purpose is to provide a rice cooker that can cook rice evenly without prolonging the cooking time.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides that in order to raise rice to boiling temperature, if the pot is heated with water remaining in the pot, the heat conduction is good and boiling is achieved. The time required for the temperature to rise is relatively short, and in this case, by setting the heater output low and using intermittent drive control that turns the heater on and off based on the temperature, it is possible to keep the inside of the pot dry. The present invention has been made with an eye to the ability to bring the entire rice to a boiling temperature without boiling the rice, and the present invention provides a heater drive control means for controlling the heater on/off and the heater output; a temperature detection device for detecting the temperature of a pot; a boiling detection means for detecting a boiling state based on the temperature detection by the temperature detection device; and a dry-up device for detecting a dry-up state based on the temperature detection by the temperature detection device. and detecting means, the heater is drive-controlled by the heater drive control means based on temperature detection by the temperature detection device, boiling detection by the boiling detection means, dry-up detection by the dry-up detection means, etc. to control the rice cooking process and unevenness. In the rice cooking process, following boil detection by the boil detection means, a stabilization process is set for a predetermined boil compensation time, and in this stabilization process, the output of the heater is lowered. At the same time, control is executed to turn off and on the heater based on a predetermined boiling maintenance temperature, and after the stabilization process is completed, heater drive control for drying up is executed to move to the uneven process. It is characterized by this.

(Function) In the rice cooking process, when the boiling detection means detects a boiling state based on the temperature detection by the temperature detection device, the stabilization process is executed. In this stabilization step, the output of the heater is set low, and the heater is controlled on and off based on the boiling state maintenance temperature, and is intermittently driven at the set output. By controlling the heater intermittently at low output, the boiling state is maintained without the pot drying up. This stabilization process is carried out during the boiling compensation time, and at the end of the stabilization process, the rice in each part of the pot is brought to a boiling temperature. After this stabilization process is executed, the heater is controlled to dry up the inside of the pot. After this, at the time of drying up, a soaking process is executed in which the heater is appropriately driven and controlled. Therefore, since all of the rice in the pot is at boiling temperature before this soaking process is started, all of the rice is gelatinized by this soaking process.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 8.

First, in FIG. 1 showing the electrical configuration and FIG. 4 showing the schematic configuration inside the rice cooker main body, 11 is a heater disposed below the pot 12, 13 is a temperature sensor, and this temperature sensor 13 is connected to the pot 12. When the pot 12 is housed in the rice cooker main body
It has come into contact with. 14 is this temperature sensor 1
3 constitutes a temperature detection device 15, which detects the temperature of the pot 12 and outputs a temperature detection signal according to the detected temperature tk.

16 is a control circuit consisting of a microcomputer, which, as is well known, is connected to a CPU 17. Clock circuit 18, memory 19
．． Input circuit 20. It includes an output circuit 21 and the like. This control circuit 16 performs driving control of the heater 12 according to a control program it owns, and detects a boiling state and a dry-up state, which will be described later, based on the detected temperature tk from the temperature detecting device 15. Based on these detection results and the detected temperature Tk, the heater 11 is turned on/off, its output is controlled, etc., and a soaking process, a rice cooking process, and a steaming process are executed. Therefore, this control circuit 16 serves as heater drive control means, boiling detection means, and dry-up detection means. Reference numeral 22 denotes a drive circuit for the heater 11, which turns on and off the heater 11 and adjusts the output, respectively, based on a heater on signal, a heater off signal, and an output adjustment signal given from the control circuit 16. This output adjustment is performed by controlling the phase of the switching thyristor, controlling the on/off duty ratio of the switching transistor, etc.

Here, the control circuit 16 sets a stabilization process during the rice cooking process that it executes, and each process control including this stabilization process will be explained with reference to FIG. 3. When the rice cooking start switch (not shown) is turned on, the heater 1
1 is set to high output H (100% output), and with this output, the heater 11 is turned on and off as appropriate based on the detected temperature tk to execute the soaking process, and the soaking process is completed. Then, the process moves to the rice cooking process. In this rice cooking process, the output of the heater 11 is turned on as it is at high output H. As a result, the pot 12 is heated, and the contents (rice and water) inside the pot 12 are heated. Incidentally, the temperature changes of this stored material, especially rice, are shown by curves a, b, and c in Fig. 3;

C represents the temperature change in the A part (the part near the inner surface of w41), the B part (the part inward from the A part), and the C part (further inward central part) shown in FIG. 4, respectively. As a result, the temperature of the pot 12 and the stored object rises due to this heating, and the detected temperature tk also rises. Here, the control circuit 16 determines the time T required for the detected temperature tk to change from 70°C to 80°C.
s, and depending on the time Ts, the capacity of the stored material ff
1-(rice cooking capacity) is detected, and a boiling compensation time To, which is the execution time of the stabilization process, is set according to the detected capacity.

In this case, as shown in Fig. 6, when the detection capacity is the maximum amount, the boiling compensation time To is set to 15 minutes, and similarly, To is set to 10 minutes at the intermediate amount, and To is set to 5 minutes at the minimum amount. Set each minute. Here, the reason why the boiling compensation time To of the stabilization process can be shortened as the rice cooking capacity becomes smaller is as follows. For example, when the rice cooking capacity is small as shown in Figure 7, the temperature increase gradients of rice in portion D and rice in portion E shown in Figure 7 are curves d and e in Figure 8. This is because, as shown, they are close to each other and have a steep slope. Therefore, the time required for all the rice to reach the boiling temperature is shorter as the rice cooking capacity becomes smaller.

Therefore, the inside of the pot 12 (especially the bottom of the pot 12) reaches the boiling temperature (
In this case, when the temperature reaches a state of 100° C.), this temperature state continues, that is, the temperature increase gradient becomes substantially flat (the detected temperature tk is substantially constant), and the control circuit 16 detects a boiling state. The detected temperature tk at this time is defined as the boiling temperature tb. By detecting this boiling state, a stabilization process during the rice cooking process is executed.

Control regarding this stabilization process will be explained with reference to the flowchart in FIG. 2 as well. When this stabilization process is started, first, as shown in step S1, the output of the heater 11 is set to an output M (50% output) lower than the previous output H, and the heater 11 is turned on and off. An off-temperature th and an on-temperature tt are set as the boiling state maintenance temperature, which is a reference value of. The off-temperature th is set to, for example, 2° C. higher than the boiling temperature tb determined by the detected temperature tk, and the on-temperature tL is set to 1° C. lower than the boiling temperature tb. After this, as shown in step S2, the time count (
parameter Tx), and turns on the heater 11 as shown in step S3, thereby causing the heater 11 to output M
Drive with. Next, as shown in step S4, the counting time Tx, that is, the execution time of the stabilization process is the boiling compensation time T.
. A judgment is made as to whether or not the period has passed. If the execution time of the stabilization process does not exceed the boiling compensation time To, the routine proceeds to a routine that follows "NO" in step S4, and in this routine, the detected temperature tk and the off-temperature th
and on-temperature tL, and turns on/off the heater 11 according to the result of the judgment. That is, if the detected temperature tk is equal to or higher than the off-temperature th, rY of step Ss
According to EsJ, proceed to step S, where heater 1
1 is turned off, and the process returns to step S4. If the detected temperature tk is lower than the on-temperature tL, rYEs is turned off in step S7.
The process moves to step S8 according to J, and here the heater 11 is turned on, and the process returns to step S4, and the detected temperature tk is
is below the off-temperature th and above the on-temperature tL, the heater 11 is not switched on and off (the previous state remains) and the process moves to step S4. Here, when the heater 11 is turned on in step S6, that is, when it is turned on on the condition that the detected temperature tk has been detected to be lower than the on-temperature tL, the on-time is a constant period with a small time width. The on time is set to T1 (a value consisting of 10 seconds to 30 seconds). This means that after the heaters 1 and 1 are turned off for the first time (off based on the off temperature th detection), the pot 1
This is to prevent the temperature at the inner bottom from becoming extremely high.

In other words, an increase of 2°C higher than the boiling temperature tb is due to a decrease in water in the inner bottom of the pot 12, so if this 2°C temperature rise occurs frequently, the pot There is a risk that the inner bottom of No. 12 will be extremely anhydrous and that the rice will become scorched during subsequent drying. As a countermeasure for this, the on time of the heater 11 is set to a constant on time T1 that is short enough to prevent the inner bottom of the pot 12 from becoming extremely waterless from the second time onwards. However, during the on state due to this on time T1, the detected temperature tk is 2°C.
When this happens, the heater 11 is forcibly turned off.

In this way, by intermittently driving and controlling the heater 11 at low output during the stabilization process using the boiling compensation time To, the pot 1
As a result, the inside of the pot 12 does not become a dryer knob state (anhydrous state), and some of the rice in the pot 12 is still not boiling when the boiling state is detected. The rice in parts B and C that are not brought to a boiling temperature state are also brought to a boiling temperature state. Until this boiling temperature state is reached, since water remains in the pot 12, the movement of the water promotes the conduction of heat from the heater 11, and thus the above-mentioned parts B and C are heated. The time required for the rice to reach boiling temperature is short. In other words, compared to the case where such a stabilization process is set during the unevenness process, the boiling compensation time T, which is the execution time of the stabilization process. can be short.

When this stabilization process is completed, the process moves to step S9 according to rYEsJ of step S4 in FIG.
Turn on for dry up and step SIG
As can be seen from this, the detected temperature tk is the dry-up temperature tf
(The temperature obtained by adding a certain range of temperature to the boiling sensitivity tb) or higher, a dry-up state is detected, and as shown in the next step Sit, the heater 11 is turned off and the process shifts to the unevenness process. do.

In this uneven process, the heater 11 is heated to the detected temperature.
The process includes so-called double-cooking, in which the temperature is turned on and off as appropriate based on k. At the beginning of this uneven journey,
Since all of the rice in pot 12 is at boiling temperature,
During the execution time of this shading process (15 minutes in this case), all of the rice is maintained at boiling temperature from the beginning.In other words, the time required for gelatinizing the rice is sufficiently secured in this shading process, and some The rice will not become hard and uneven cooking will not occur.

Incidentally, in the above embodiment, a case was described in which ordinary rice is cooked, but the object to be cooked may be rice with ingredients to obtain so-called takikomi-gohan.In this case, since the ingredients are usually larger than the rice, In the past, the movement of water (heat conduction) was hindered and the rice often became hard, but in this example, this problem can be eliminated, so it is particularly effective for obtaining such cooked rice. be. Further, in the above embodiment, each function such as the heater drive control means, the boiling detection means, the dry-up detection means, etc. is obtained by a control circuit consisting of a microcomputer, but each function is obtained by an individual electronic circuit. You can.

In addition, the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without departing from the scope of the invention.

[Effects of the Invention] As is clear from the following description, the present invention sets a stabilization process using a predetermined boiling compensation time during the rice cooking process following boiling detection, and in this stabilization process, the heater By setting the output low and controlling the heater to turn on and off based on a predetermined boiling state maintenance temperature, all of the rice can be heated in a short period of time while maintaining the situation in which the inside of the pot does not dry up. It can reach a boiling temperature state,
Therefore, all of the rice can be α-gelatinized in the subsequent shading process, and the cooking time is shorter compared to when such a stabilization process is set during the shading process, and overall, the lengthening of the rice cooking time can be suppressed. It has an excellent effect of reliably eliminating uneven cooking of rice.

[Brief explanation of the drawing]

1 to 8 show one embodiment of the present invention, FIG. 1 is a block diagram of the electrical configuration, FIG. 2 is a flowchart for explaining the operation, and FIG. 3 shows the output state of the heater and the details of each part. Figure 4 is a diagram showing temperature changes, Figure 4 is a longitudinal cross-sectional view showing the schematic configuration of the pot portion, Figure 5 is a diagram showing the heater output state and detected temperature changes to explain the stabilization process, Figure 6 is a diagram showing boiling FIG. 7 is a diagram corresponding to FIG. 4 in a state where the rice cooking capacity is small, and FIG. 8 is a diagram equivalent to FIG. 3 in the same state. 9 and 10 are views corresponding to FIG. 4 and 10, respectively, showing a conventional example. This is a diagram equivalent to Figure 3. In the figure, 11 is a heater, 12 is a pot, 13 is a temperature sensor, 1
5 is a temperature detection device, and 16 is a control circuit (heater drive control means, boiling detection means, dry-up detection means). Murashi process JP, 4 figure bird 5 figure jP, 6 figure? Figure 17 Figure 8 jP, Figure 9 IIA to IK ″4

Claims (1)

[Claims] 1. Heater drive control means for controlling on/off of the heater and heater output; a temperature detection device for detecting the temperature of the pot; boiling detection means for detecting a boiling state based on temperature detection by the temperature detection device; and dry-up detection means for detecting a dry-up state based on temperature detection by the temperature detection device, and the heater is configured to be driven and controlled by the heater drive control means to execute the rice cooking process and the unevenness process, wherein during the rice cooking process, following the boiling detection by the boiling detection means, stabilization is performed by a predetermined boiling compensation time. In this stabilization process, the output of the heater is set low, and the heater is turned off and on based on a predetermined boiling state maintenance temperature. A rice cooker characterized in that the heater drive control is executed to shift to an uneven process.