JP3539402B2 - rice cooker - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a rice cooker that appropriately performs heat retention control according to a heat retention amount or an environmental change and contributes to energy saving.
[0002]
[Prior art]
Generally, a rice cooker has a plurality of heating means such as a work coil, a heat retaining heater and a lid heater, and automatically cooks and keeps heat by making full use of these heating means, thereby always providing an optimal rice to a user. It is widely known as a convenient device.
[0003]
That is, as shown in FIG. 3, the rice cooker process includes a water absorption process for absorbing sufficient water into the rice, a heating process for heating the rice to increase the heat power, and peeling the cooked rice. A rice cooking process consisting of a rice drying process, and a process after the rice cooking process, comprising a plurality of sets of temperature control sections, a heating section having a heating section and a maintenance section, and each step includes a work coil, a heating heater and A plurality of heating means such as a lid heater controls the output based on a detection signal of a temperature sensor that detects the temperature of the inner pot, and optimal process control is performed. Particularly, in a warming process, a user cooks for a long time. Insulation control is performed so that rice can be eaten.
[0004]
The present applicant has already proposed a control method as shown in FIG. 3 as heat retention control so that a user can eat freshly cooked rice for a long time. The outline of this control is to divide the heat-retention temperature into three stages, raise the heat-retention temperature with the passage of time, set up a temperature-raising section and a maintenance section at the time of raising the heat-retention temperature, sterilize the rice, and perform odor and yellowing. This is a long-time heat-retention control that suppresses flaking and the like.
[0005]
However, such heat retention control is very effective for making rice last longer. However, when the rice is warmed, the remaining amount of rice is gradually reduced, but if the amount of rice is small, the energy consumption, which is the heat retention output, should be small, but since it is controlled uniformly regardless of the amount of rice It was not enough to save energy.
[0006]
In addition, rice cookers are portable, and when keeping warm for a long time, the surrounding environment may change like day and night, or the place may change from a warm place to a cold place, Conventional rice cookers do not provide any means for responding to environmental changes such as a change in room temperature. Therefore, even if the output temperature is controlled so that the temperature maintained during each temperature adjustment section and the maintenance time period during each maintenance section become a temperature or time corresponding to the amount of rice, if the room temperature decreases, the same output control will require additional time. It consumes extra energy instead, and if the room temperature rises, the output energy will be too large and greatly exceed the intended temperature, so that extra energy will be used and the control will be coarser. However, there has been a problem that proper heat control cannot be expected.
[0007]
[Problems to be solved by the invention]
The present invention uses the room temperature sensor that is different from the temperature sensor that detects the temperature of the inner pot, takes in room temperature data at the time of heat keeping control, and varies the output of the warming temperature according to the ambient temperature of the room at that time. It is an object to provide a rice cooker that solves the above.
[0008]
[Means for Solving the Problems]
To achieve the above object, the present invention employs the following configuration.
[0009]
In the invention according to claims 1 and 2, the inner pan, a heating unit for heating the inner pan, a heating control unit for controlling a heating state of the heating unit, and a temperature sensor for detecting a temperature of the inner pan. In the rice cooker provided, a room temperature sensor for detecting the indoor temperature is provided, and the heating control at the time of keeping the temperature after the rice cooking process is performed by using the temperature data before the rice heating detected by the room temperature sensor for a predetermined time at the time of keeping the temperature. After the elapse, the temperature is controlled using the temperature data at that time, and the actual room temperature is estimated based on a predetermined threshold, and the predetermined time is detected by the room temperature sensor during the temperature maintenance. Configuration where the temperature is time to stabilize.
[0010]
With such a configuration, the heat retention control in each temperature control section is controlled by an output corresponding to the room temperature, that is, by a large output when the room temperature is low, and by a small output when the room temperature is high. Do it properly. In addition, accurate control can be performed without malfunction since the temperature data before heating the rice is used. Further, even if the room temperature data obtained by inferring the heat retention control in each temperature control section is not significantly different from the actually measured value, it is the immediately preceding data, so that it is not affected by environmental changes and used. Since the data is stable temperature data, accurate control can be performed.
[0011]
In the invention according to the third aspect, when there is a temperature raising step at the time of keeping the temperature, the temperature data at the time of stability before the temperature is raised is used. With such a configuration, even if there is a temperature raising step at the time of temperature keeping, temperature data at the time of stability before temperature rise is used for the next temperature keeping control, so that accurate control can be performed without malfunction.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
(Structure of rice cooker body)
FIG. 1 is an overall sectional view of the rice cooker. The rice cooker 1 includes a rice cooker main body 2 and a lid 3, and the rice cooker main body 2 is a synthetic resin bottomed cylindrical inner case 5 in which the inner pan 4 can be arbitrarily set, and an outer casing. It is formed of an outer case 6 made of a synthetic resin, and the two cases 5 and 6 are joined together by means such as forced fitting. On the outer peripheral surface of the inner case 5, a bottom coil 7 and a corner coil 8 each composed of a work coil are provided at a bottom portion and a corner portion from the bottom portion to the side surface, and a heat retaining heater 11 is disposed at a side portion thereof. Heating control and heat retention control depending on the strength are performed by a known control device that does not perform heating. Needless to say, a work coil may be separately provided on the side part.
[0013]
The coils 7 and 8 are arranged on a coil base 9, and a through-hole is provided in the center of the coil base 9 so as to penetrate in a vertical direction. A temperature sensor 10 in which a reed switch for detecting a state and a thermistor for detecting the temperature of the inner pan 4 are provided is provided. The temperature sensor 10 has a built-in spring, and when the inner pot 4 is not set, the tip protrudes above the bottom of the inner case 5. When the inner pot 4 is set, the inner pot 4 is set. When the inner pot 4 is set, the safety device is not activated unless the inner pan 4 is set.
[0014]
The inner pan 4 is formed of an iron-based metal such as stainless steel capable of self-heating by eddy currents induced therein by the work coils 7 and 8, and has the same shape as the inner case 5. By setting the inner pan 4 in the inner case 5 with the substantially W-shaped cross section, the temperature sensor 10 is turned on and the coils 7 and 8 can be energized, and the rice cooking switch is turned on. Then, the inner pot 4 is heated by the Joule heat caused by the eddy current, and the contents such as cooked rice and the like put therein are uniformly heated, and the rice is cooked efficiently.
[0015]
On the other hand, the lid 3 is composed of a lid plate 12 made of synthetic resin and a radiating plate 13 made of a good heat conductor fixed to the lid plate 12 by screws 22 so as to form the lower surface of the lid 3. In addition, a hollow portion 15 filled with a heat insulating material 16 is formed between the cover plate 12 and the heat radiating plate 13, and an electric heater that generates resistance heat when energized is formed on the upper surface of the heat radiating plate 13. The lid heater 17 is fixed by a mounting plate 18 and quickly vaporizes the condensed liquid droplets to prevent white bokeh of the rice. The heating method using the lid heater 17 may be the above-described heating method, the IH type, the high-frequency type, or the like. The heat insulating structure formed on the lid 3 is vacuum heat insulating instead of the heat insulating material 16. It may be a structure.
[0016]
A cylindrical opening 19 is integrally formed with the lid 12 at the center of the lid plate 12, and a cylindrical body 21 accommodating the ball valve 20 therein is disposed in the opening 19. At the same time, the cylindrical body 21 is in contact with the inner peripheral surface of a ring-shaped seal member 23 made of a synthetic resin which is simultaneously attached when the heat radiating plate 13 is attached to the cover plate 12 with the screw 22. It is detachable from the lid plate 12. A steam port 24 is provided on the upper surface, and when the steam pressure in the inner pan 4 becomes equal to or higher than a predetermined value, the steam is pushed up the ball valve 20 and discharged from the steam port 24 to the atmosphere. A seal packing 25 is sandwiched on the outer peripheral edge of the heat radiating plate 13, and the seal packing 25 contacts the upper edge of the inner pot 4 when the lid is closed, and dissipates heat in the inner pot 4. Is preventing.
[0017]
A hinge member 27 rotatably pivoted by a hinge pin 26 is provided at an upper portion of a rear end portion of the rice cooker main body 2. The hinge member 27 includes a hinge arm 28 having a substantially U-shape in plan view and a hinge cover 29 also covering the lower surface of the hinge arm 28 and having a substantially U-shape in plan view. And the lid 3 is made detachable with respect to this hinge member, thereby enabling the lid 3 to be washed in a round manner.
[0018]
An operation panel 30 is provided in a tapered shape on the upper front side of the outer case 6 of the rice cooker main body 2. The operation panel 30 includes various operation switches and various switches. And a display unit for displaying a setting state to be set. A substrate 31 on which various control elements are mounted is arranged in the display unit, and a room temperature sensor 32 is mounted on the substrate 31. Then, using the detection signal of the room temperature sensor 32, heating control at the time of warming described later is performed.
[0019]
As described above, in the rice cooker having the above configuration, at the time of cooking rice, the inner pot 4 generates heat substantially uniformly from the bottom wall to the side wall by driving the work coils 7 and 8. In the process of absorbing rice and rice immersed in the water inside 4, even the upper side of the inner pot 4 is evenly heated to make it possible to absorb water almost evenly, and even when the amount of cooked rice is large, etc. 4 can be cooked efficiently without substantially uneven heating by heating the entirety of the product substantially uniformly. At the time of heat retention, the inner pot 4 is driven by driving the heat retaining heater 11 provided at the upper portion of the side wall of the inner pot 4 together with the work coils 7 and 8 corresponding to the side walls from the bottom wall of the inner pot 4. Is uniformly heated with an appropriate amount of heating from the bottom wall portion to the side wall portion and the upper portion, thereby realizing heat retention without heating unevenness.
[0020]
(Configuration of control circuit section)
Next, FIG. 2 shows a configuration of a control circuit unit such as a work coil, a heat retention heater, a lid heater and the like centered on a microcomputer control device 100 for controlling rice cooking and heat retention of the rice cooker body configured as described above.
[0021]
In the figure, reference numeral 40 denotes a microcomputer control unit (CPU) for controlling rice cooking and heat keeping. The microcomputer control unit 40 is mainly composed of a microcomputer, for example, an inner pot 4 or a room temperature detection circuit, a work coil drive control. It comprises a circuit section, an oscillation circuit section, a reset circuit section, a drive control circuit section such as a warming heater and a lid heater, a power supply circuit section, a display section such as a liquid crystal and an LED lamp, an operation switch section, and the like.
[0022]
Then, first, an inner pot detection temperature signal from the inner pot temperature detection sensor 10 is input to an inner pot temperature detection circuit 48 provided corresponding to the temperature sensor 10 provided on the bottom wall portion of the inner pot 4, and furthermore, A room detection temperature signal from the room temperature sensor 32 provided on the substrate 31 is input to a temperature detection circuit 49.
[0023]
Further, the work coil drive control circuit section includes, for example, a pulse width modulation circuit 46, a synchronization trigger circuit 53, an IGBT drive circuit 45, an IGBT 50, and a resonance capacitor 51. By controlling the pulse width modulation circuit 46 by the microcomputer control unit 40, the output values of the work coils 7 and 8 and the ON duty ratio at the same output value (for example, according to each step of rice cooking and heat retention) For example, the target heating temperature and the heating pattern of the inner pot 4 in each step of the same rice cooking and heat retention can be appropriately variably controlled in consideration of the amount of cooked rice by appropriately changing the respective steps of the same rice cooking and heat keeping, and uniform water absorption action. In addition, appropriate heating output control is performed to cook rice without uneven heating and to achieve a high-quality heat retaining action.
[0024]
Reference numeral D denotes a flywheel diode of the IGBT 45, reference numeral 55 denotes a power supply side rectifier circuit incorporating a diode bridge for driving the work coil inserted between the home AC power supply 57, and reference numeral 52 denotes a smoothing circuit thereof. is there.
[0025]
On the other hand, reference numeral 11 denotes the above-described heat retention heater, 17 denotes a lid heater, and the heat retention heater 11 is turned on and off at a desired output and duty ratio by a heat retention heater driving circuit 56 and the lid heater 17 is driven by a lid heater driving circuit 54, respectively. It is designed to be driven.
[0026]
Further, reference numeral 41 denotes a display unit such as a liquid crystal or LED, 43 denotes a notification unit such as a buzzer, 42 denotes various operation switch units such as a rice cooker switch, a heat retention switch, a timer switch, a cancel switch, and 47 denotes a clock reference control signal forming signal. An oscillation circuit 44 is a reset circuit.
[0027]
(Embodiment)
Next, the contents of the heat retention control according to the embodiment of the present invention performed using the above-described microcomputer control unit 40 will be described with reference to the time chart of FIG. 3 and the flowcharts of FIGS.
[0028]
First, the outline of the rice cooking process and the heat retention process will be described with reference to the time chart of FIG. 3. In the rice cooking process, first, the output of the work coils 7 and 8 is increased to a predetermined value, so that the water absorption process for making the rice absorb water first. Yes, when sufficient water is absorbed into rice, there is a heating process that raises the output sharply and cooks the rice at once.Based on the heating time in this heating process, the amount of rice in the inner pot is A certain number is determined, and the subsequent boiling maintenance time is determined based on the total number of the rice amounts. Thereafter, the rice cooked in the steaming process is sufficiently uneven, and the rice is put into an optimal state and the rice cooking process is completed.
[0029]
When the rice cooking process is completed, the process proceeds to the heat retaining process. First, the low-temperature heat retaining temperature, which is the first target heat retaining temperature, is set, and the rice after the rice cooking is naturally cooled or uses a cooling fan until the temperature reaches this temperature. The temperature drops due to cooling. At this time, the work coils 7 and 8 and the heat retaining heater 11 are turned off, but the lid heater 17 is turned on to evaporate condensed water that condenses on the inner surface of the heat radiating plate 13 below the lid 3 and makes the rice white. State.
[0030]
When the temperature decreases to a predetermined first target heat retention temperature, the first target heat retention control is executed. In this case, the total number determination data for cooking rice is used, and based on the total number determination data, Is determined. That is, the temperature is set to 66 ° C. at the time of the determination of the total number at the time, 65 ° C. at the time of the medium determination, and 64 ° C. at the time of the minimum determination at the time of the first temperature control section shown in FIG. The output control of the work coils 7 and 8, the heating heater 11 and the lid heater 17 is performed based on the detection signals of the temperature sensor 10 and the room temperature sensor 32 so that the first target heating temperature according to the result of the number-of-intervals determination is obtained. It is performed for 6 hours, the time when rice does not deteriorate.
[0031]
The output control of each heating means at the time of the first target heat retention temperature control is performed based on the detection signal of the room temperature sensor 32. The first output control to enter the first target heat retention temperature control is the temperature before rice heating. This is performed using data, and thereafter, the actual room temperature is estimated based on a predetermined threshold. And the time to estimate the actual room temperature is set as the room temperature sensor determination prohibition section for 2 hours after the mura process, which is the temperature drop time at which a rapid temperature change occurs, and is not performed in that section. This is performed after the end of the room temperature sensor determination prohibition section. Therefore, the first output control to enter the first target heat retention temperature control or the subsequent output control of the first target heat retention temperature can be performed based on the actual room temperature data or the immediately previous stable room temperature data. Can be done.
[0032]
However, if the low-temperature state is continued for more than 6 hours, odor will be generated. Therefore, within 7 hours after the lapse of the 6 hours and until the lapse of 13 hours, the temperature is slightly lower than the first target heat retention temperature. The generation of odor and the like is suppressed by maintaining the second target heat retaining temperature at a high level.
[0033]
However, even if the target heat retaining temperature is changed at the boundary of 6 hours, the propagation of various bacteria cannot be prevented by itself. Therefore, this heat retention control is performed in a temperature rise step (first temperature rise section) of approximately 7 minutes in which the temperature is suddenly heated to 93 ° C. when the temperature is changed from the first target heat retention temperature to the second target heat retention temperature. In addition, a maintenance step (first maintenance section) for maintaining the temperature at 87 ° C., which is a low temperature, for a predetermined time is provided, and the temperature of the rice is raised to perform sterilization.
[0034]
In this case, a total number determination for determining the remaining amount of rice in the inner pot at that time based on the heating time during the first heating section is performed. The maintenance time of the first maintenance section is determined to be 30 minutes, and when the remaining time of the medium rice having the medium heating time is medium, the maintenance time of the first maintenance section is determined to be 20 minutes, and the heating time is short. When the remaining amount of rice is low, the first maintenance section is executed by determining the maintenance time of the first maintenance section to be 5 minutes. In addition, as a result of the total number determination, when the remaining rice amount is equal to or less than the predetermined value, the heat retention is stopped.
[0035]
When the steps in the first heating section and the first maintaining section are completed, the heat control at the second target heat retaining temperature slightly higher than the first target heat retaining temperature is performed. The second target heat retention temperature is automatically determined from the result of the total number determination determined according to the temperature rise time during the first temperature rise section. That is, when the remaining amount of rice is large, the second target heat retaining temperature is set to 70 ° C., when the remaining amount of rice is medium, the second target heat retaining temperature is set to 69 ° C., and when the remaining amount of rice is low, the second target heat retaining temperature is set to second. By setting the target heat retention temperature to 68 ° C., each second target heat retention temperature control is executed.
[0036]
Then, at the time of the second target heat retaining temperature control, although the room temperature data is obtained by estimating the actual room temperature based on a predetermined threshold, the output control of each heating means is performed based on the data. As the room temperature data in that case, data at the time of stability before the temperature rise is used. The reason is that if there is a temperature raising step, appropriate data cannot be obtained due to a large temperature change during the step or during a certain period after the step. A room temperature sensor determination prohibition section similar to the room temperature sensor determination prohibition section for 2 hours after the mura processing is provided for 2 hours after the start of the first temperature raising step. It is prohibited and the data at the time of stabilization before temperature rise is used. Note that the temperature data is taken into the microcomputer after a predetermined time elapses during the heat retention every one second or when a rapid temperature change occurs.
[0037]
As a result, in the second temperature control section, the middle temperature keeping temperature control is performed at the second target keeping temperature according to the remaining rice amount. Of course, the second heat retention temperature control at the medium heat retention temperature is performed for 7 hours by output control based on room temperature data, and suppresses the smell, yellowing, and dryness of rice.
[0038]
However, as in the case of the low-temperature keeping temperature control, if the medium temperature state is continued for more than 7 hours, the odor will still occur, so after the lapse of 13 hours, the second target keeping temperature slightly higher than the second target heat retaining temperature. The target temperature of 3 is maintained to suppress the generation of odor.
[0039]
However, even if the target heat-retention temperature is changed at the boundary of 13 hours, the propagation of various bacteria cannot be prevented by itself. Therefore, this heat retention control is performed in a temperature rise step (second temperature rise section) of about 7 minutes in which the temperature is suddenly heated to 93 ° C. when the temperature is changed from the second target heat retention temperature to the third target heat retention temperature. In addition, a maintenance step (second maintenance section) for maintaining the temperature at 87 ° C., which is a low temperature, for a predetermined time is provided, and the temperature of the rice is raised to perform sterilization.
[0040]
In this case, the total number of rice remaining in the inner pot is determined based on the temperature rising time at the time of the second temperature rising section at that time. The maintenance time of the second maintenance section is determined to be 30 minutes, and when the heating time is medium and the remaining amount of rice is medium, the maintenance time of the second maintenance section is determined to be 20 minutes, and the heating time is determined. When the small remaining amount of rice is small, the second maintenance section is executed by determining the maintenance time of the second maintenance section to be 5 minutes. In addition, as a result of the total number determination, when the remaining rice amount is equal to or less than the predetermined value, the heat retention is stopped.
[0041]
When the steps in the second heating section and the second maintaining section are finished, the heat control at the third target heat retaining temperature slightly higher than the second target heat retaining temperature is performed. The target heat retention temperature of No. 3 is automatically determined from the result of the total number judgment performed during the second temperature raising section. That is, when the remaining amount of rice is large, the third target heat retaining temperature is 71 ° C., when the remaining amount of rice is medium, the third target heat retaining temperature is 70 ° C., and when the remaining amount of rice is small, the third target heat retaining temperature is third. By setting the target heat retention temperature to 69 ° C., each third target heat retention temperature control is executed.
[0042]
Then, at the time of the third target heat retention temperature control, although the room temperature data is obtained by estimating the actual room temperature based on a predetermined threshold, the output control of each heating means is performed based on the data. In this case, the data at the time of stabilization before the temperature rise is used as the room temperature data. The reason is that if there is a temperature raising step, a large temperature change occurs during the step or during a certain period after the step, and proper data cannot be obtained. A room temperature sensor determination prohibition section similar to the room temperature sensor determination prohibition section for 2 hours after the temperature raising step is provided for 2 hours after the start of the second temperature raising section. It is prohibited and the data at the time of stabilization before temperature rise is used.
[0043]
As a result, in the third temperature adjustment section, the third target temperature control according to the third target temperature control temperature corresponding to the remaining amount of rice and the high temperature control temperature control based on the output control based on the room temperature data is performed. Is performed until cutting is performed, and the odor, yellowing and fluffiness of rice are suppressed for a long time.
[0044]
Next, the flow of the above-described heat retention process will be described with reference to the flowchart of the main routine showing the contents of the overall control system of the heat retention control of FIG. 4 and the flowchart of the subroutine of FIGS.
[0045]
In the heat retention control system, after the completion of cooking at the end of the rice cooking process is detected, the heat retention control (heat retention process) is started on the condition that a predetermined uneven time has elapsed.
[0046]
When the heat retention control is started, first, a menu determination is made in step S1, and when the rice cooking menu is selected from white rice, non-washed rice, and fast-cooking, the process proceeds to step S2 and the subsequent steps to execute the present invention. However, if the occurrence is selected, the process proceeds to step S3, where 66 ° C., which is the high set temperature A, is selected, and the process proceeds to step S13, where the third target heat retaining temperature control is performed. If the cooking and brown rice menus are selected in step S1, the process proceeds to step S4, where 66 ° C., which is the same high setting temperature A as in step S3, is selected, and the process proceeds to step S5, where the first target heat retaining temperature control is performed. When the menu of the porridge is selected in step S1, the porridge itself is prepared on the assumption that the porridge itself is eaten immediately, and since the porridge itself becomes pasty when cooled, the heat retention control is not performed.
[0047]
As described above, when white rice, non-washed rice, and fast-cooking are selected in step S1, the process proceeds to step S2. In step S2, the set temperature based on the total number determination value is read, and the set temperature is read. Is performed in step S5. In this case, the set temperature read out in step S2 is a temperature determined based on the total number determination data at the time of cooking rice, that is, 66 ° C. when the total number determination is the highest at that time, and 65 ° C. when the medium level determination is performed. At the time of determination that the temperature is the smallest, 64 ° C. is selected. Based on the set temperature selected at that time, the first target heat retention temperature control is performed in step S5.
[0048]
The first target heat retention temperature control in step S5 is executed based on a flowchart as output control of the heating means based on room temperature data, which is a subroutine shown in FIG. That is, when the first target heat retaining temperature control starts, the process proceeds to step S1, where a set temperature corresponding to the total number selected in step S2 of the main routine of FIG. 4 is set, and subsequently, the process proceeds to step S2. , It is determined whether the set temperature is high. If the determination in step S2 is low and the remaining amount of rice is low and the set temperature is 64 ° C. or lower, the process proceeds to step S4, and the outputs of the work coils 7 and 8 are turned off.
[0049]
When the remaining amount of the rice, which is determined to be high in step S2, is medium or higher and the set temperature is 65 ° C. or 66 ° C., the process proceeds to step S3, where the output of the work coils 7, 8 is reduced to 1/60 of the 60% output. The ON control with a low duty ratio of 16 is performed, and then the process proceeds to step S5 to fetch room temperature data obtained according to a flowchart of room temperature data fetching control shown in FIG. 6 described later.
[0050]
After fetching the predetermined room temperature data in step S5, the process proceeds to step S6, where it is determined whether the fetched data is higher than the predetermined value t1 of 12 ° C. Proceeding to S7 and step S8, ON control is performed on the heat retaining heater 11 at a high duty ratio of 12/16 and further on the lid heater 17 at a relatively high duty ratio of 4/16.
[0051]
If a negative determination is made that the room temperature is higher than 12 ° C. in step S6, the process proceeds to step S9, where it is determined whether the room temperature is between 12 ° C. and 25 ° C., which are medium temperatures. As a result, when an affirmative determination is made that the room temperature is an intermediate temperature between 12 ° C. and 25 ° C., the process proceeds to step S10 and step S11, in which the heat retention heater 11 is turned on at a high duty ratio of 10/16 and the lid heater 17 is turned on. Are turned on at a low duty ratio of 2/16.
[0052]
Further, when a negative determination is made in step S9 because the room temperature is a high temperature higher than 25 ° C., the process proceeds to step S12 and step S13, in which the heat retention heater 11 is turned on at a high duty ratio of 8/16 and the lid heater 17 is turned on. Is controlled at a low duty ratio of 2/16.
Then, when the output of the heating means is determined based on the room temperature data, the first target thermal insulation temperature control in step S5 of FIG. 4 is executed based on the output so that the thermal insulation temperature is determined in advance as a result of the combination determination. Is done.
[0053]
The room temperature data acquisition control in step S5 in FIG. 5 is performed according to a flowchart which is a subroutine shown in FIG. 6. Referring to FIG. 6, the characteristic of this flow is that when the room temperature data is unstable, A prohibited section (the four lowermost sections shown in FIG. 3) is provided to prohibit data acquisition in this section, and the first output control to enter the first target heat retention temperature control is performed before cooking rice. The temperature data is used, and thereafter, the actual room temperature is estimated based on a predetermined threshold value.
[0054]
That is, first, it is determined whether the rice is being cooked in step S1 before the heat retention, and in the case of a negative determination, the process proceeds to step S2, where the room temperature at the time of stop before heating the rice is measured, and the data is stored in the microcomputer. The data is updated every second in step S3, rewritten as new data and stored in the microcomputer.
[0055]
If an affirmative determination is made in step S1, the process proceeds to step S4, where it is determined whether or not the temperature is being maintained. If the temperature is not being maintained, this flow is terminated. In step S5, it is determined whether or not the section is a room temperature data acquisition prohibited section. As shown in FIG. 3, the room temperature data capture prohibited section is for 2 hours after the rice cooking process and the rice drying process, 2 hours after the start of the first heating section, and 2 hours after the start of the second heating section. Is applicable. When the determination is negative in step S5, which is not the room temperature data acquisition prohibition section, this flow is ended, and when the determination is affirmative, the process proceeds to step S6 to determine the room temperature during warming. At this time, the room temperature is determined by using the temperature data before the heating of rice cooking at the first time of entering the first target heat retaining temperature control, and thereafter, the actual room temperature is determined based on a predetermined threshold value. Guess.
[0056]
In this case, the temperature data before the rice cooking is based on the above-described heating at low temperature lower than 12 ° C, medium temperature of 12 ° C or higher and 25 ° C or lower, and high temperature higher than 25 ° C. Means are output. When the actual room temperature is estimated based on a predetermined threshold value, the detected temperature of 39 ° C. at that time is set to a temperature corresponding to 12 ° C. before rice cooking, and 57 ° C. is set to 57 ° C. before rice heating. By corresponding to 25 ° C., a temperature lower than 39 ° C. is estimated as a low temperature, a temperature of 39 ° C. or more and 57 ° C. or less is estimated as a medium temperature, and a temperature higher than 57 ° C. is estimated as a high temperature. The means will be output controlled. When it is determined in step S6 that the room temperature at the time of warming is determined, the process proceeds to step S3, where the room temperature data is updated, and this flow ends.
[0057]
When the first target heat retention temperature control in step S5 in FIG. 4 ends, the process proceeds to step S6, and it is determined whether six hours have elapsed. Here, if a negative determination is made, the process returns to step S5, and the first target heat retaining temperature control is continuously performed. However, if an affirmative determination is made, the process proceeds to step S7, and the first temperature increasing step is performed. .
[0058]
This first temperature raising step is a step in a first temperature raising section, and is performed according to a flowchart which is a subroutine shown in FIG. That is, when the first heating process is started, the process proceeds to steps S1 and S2, where 420 seconds which is the heating monitoring time of the heating monitoring timer is set in step S1, and the total number determination timer is set in step S2. Start.
[0059]
When the total number determination timer is started in step S2, the process proceeds to step S3, in which the work coils 7, 8 are turned on with a 70% output and a high duty ratio of 9/16, and the heat retention heater 11 is turned on with a high duty ratio of 10/16. Further, the temperature of the rice cooker is rapidly increased to 93 ° C. by controlling the lid heater 17 to ON at a relatively high duty ratio of 5/16, and the rice is sterilized by heating the rice. Then, the remaining amount of rice in the rice cooker is determined by measuring the temperature rise time at that time, and the maintenance time of the subsequent maintenance process and the control temperature at the time of the second target heat retention temperature control are determined.
[0060]
Thereafter, the process proceeds to step S4, where it is determined whether or not the set time of 420 seconds set in step S1 has elapsed. If the determination is affirmative, the process proceeds to step S6, where the timer count for the total number determination is terminated, and the flow proceeds to step S6. To end. Then, in the case of a negative determination that the set time has not yet elapsed in step S4, the process proceeds to step S5, and it is determined whether the temperature of the inner pot is equal to or higher than 92 ° C., and in the case of a negative determination, the process returns to step S3 to further increase the temperature. Heating is continued. In the case of an affirmative determination that the temperature of the inner pot becomes 92 ° C. or higher in step S5, the process proceeds to step S6, in which the timer count for the total number determination ends, and this flow ends.
[0061]
When the flow of FIG. 7 is completed in this manner, the process returns to FIG. 4 again, proceeds to step S8, and the first maintenance process is performed. The first maintenance step in step S8 is a step in a first maintenance section, and is performed according to a flowchart which is a subroutine shown in FIG. That is, when the first maintenance process starts, the process proceeds to step S1, and the timer count value of the total number determination counted in step S6 of FIG. 7 is read in step S1.
[0062]
When the timer count value for the total number determination is read in step S1, the process proceeds to step S2, where the maintenance time according to the timer count value is determined. That is, when the timer count value is small, the amount of the remaining rice is determined to be the minimum amount, the maintenance time of 5 minutes is determined, and when the timer count value is medium, the amount of the remaining rice is determined to be medium, and the maintenance time is determined. The time of 20 minutes is determined. If the timer count value is large, the amount of the remaining rice is determined to be the maximum amount, and the maintenance time of 30 minutes is determined.
[0063]
Then, when the maintenance time is determined, the process proceeds to step S6, and it is determined whether the amount of rice is greater this time than in the previous time. This step is for preventing the microcomputer from erroneously determining that the amount of rice has increased. As a result, in the case of an affirmative determination, it is determined that the microcomputer has made an erroneous determination, the process proceeds to step S7, and since the previous rice amount is correct, the previous data is used, and the determination in the next step, step S9, is performed. However, if a negative determination is made in step S6, the process proceeds to step S8, but in this case, the data is updated to the current data on the assumption that a correct determination has been made.
[0064]
Thereafter, the process proceeds to step S9, and the maintenance control at the maintenance temperature of 87 ° C. is performed after step S9. That is, when the temperature of the inner pan is 87 ° C. or more, the process proceeds to step S10, in which the outputs of the work coils 7, 8 and the heater 11 are turned off, and the process proceeds to step S12. If the temperature of the inner pot has not yet reached 87 ° C. in the negative, the process proceeds to step S11, in which the work coils 7, 8 are turned on with a 70% output, a high duty ratio of 9/16, and a heat retention heater. 11 is controlled at a high duty ratio of 10/16, and the lid heater 17 is controlled at a relatively low duty ratio of 3/16. Thereafter, the process proceeds to step S12, in which it is determined whether the maintenance process time of 5, 20, or 30 minutes has elapsed. If not, the process returns to step S9 and repeats. If it is determined that the flow has been performed, the flow ends.
[0065]
When the flow in FIG. 8 ends, the process returns to FIG. 4 and proceeds to the second heat retaining step of the next step S9, where the second target heat retaining temperature control is performed. This second target heat retaining temperature control is performed substantially in accordance with the flowchart of FIG. 5, similarly to the first target heat retaining temperature control in step S5.
[0066]
That is, when the second target heat retention temperature control is started, the process proceeds to step S1, and set temperatures (68 ° C., 69 ° C., 70 ° C.) corresponding to the total number selected in step S7 of the main routine of FIG. At the same time, it is determined in step S2 whether the set temperature is high. If the determination in step S2 is low and the remaining amount of rice is low and the set temperature is 68 ° C. or lower, the process proceeds to step S4 and the outputs of the work coils 7 and 8 are turned off.
[0067]
When the remaining amount of the rice, which is determined to be high in step S2, is medium or higher and the set temperature is 69 ° C. or 70 ° C., the process proceeds to step S3, where the outputs of the work coils 7, 8 are reduced to 1/60 of the 60% output. ON control with a low duty ratio of 16 is performed, and then the process proceeds to step S5 to fetch room temperature data, which is an estimated value obtained according to the flowchart of the room temperature fetch control shown in FIG. Of course, the room temperature data, which is the estimated value, is the room temperature sensor determination prohibition section for 2 hours after the start of the first temperature raising step, so that it is performed based on the stable data of the first heat preservation section before that. After 2 hours from the start of the first temperature raising step, the data of the second heat retaining step is taken in, and the data is updated every second.
[0068]
After capturing the room temperature data, which is the estimated value in step S5, the process proceeds to step S6, where it is determined whether the captured data is greater than the predetermined value t1 of 39 ° C. Then, the process proceeds to steps S7 and S8, in which the heater heater 11 is turned on at a high duty ratio of 12/16, and the lid heater 17 is turned on at a relatively high duty ratio of 4/16.
[0069]
If the negative determination is made at step S6 that the room temperature is higher than 39 ° C., the process proceeds to step S9, where it is determined whether the room temperature is between 39 ° C. and 57 ° C., which are medium temperatures. As a result, when an affirmative determination is made that the room temperature is an intermediate temperature between 39 ° C. and 57 ° C., the process proceeds to step S10 and step S11, in which the insulated heater 11 is turned on at a high duty ratio of 10/16 and the lid heater 17 is turned on. Are turned on at a low duty ratio of 2/16.
[0070]
Further, when the negative determination is made in step S9 because the room temperature is a high temperature higher than 57 ° C., the process proceeds to step S12 and step S13, in which the heat retention heater 11 is turned on at a high duty ratio of 8/16 and the lid heater 17 is turned on. Is controlled at a low duty ratio of 2/16.
[0071]
Then, when the output of the heating means is determined based on the room temperature data, the second target thermal insulation temperature control in step S9 in FIG. 4 is performed based on the output so that the thermal insulation temperature is determined in advance as a result of the combination determination. Be executed.
[0072]
When the second target heat retaining temperature control in step S9 in FIG. 4 ends, the process proceeds to step S10, and it is determined whether 13 hours have elapsed. If a negative determination is made here, the process returns to step S9 and the second target heat retention temperature control is continuously performed. However, if an affirmative determination is made, the process proceeds to step S11 and step S12, and the second temperature raising step is performed. And a second maintenance step. The second temperature raising step in step S11 is a step in a second temperature raising section, and is substantially the same as the first temperature raising step in step S7, and is performed according to a flowchart of a subroutine shown in FIG. Will be That is, when the second heating process starts, the process proceeds to steps S1 and S2, where 420 seconds which is the heating monitoring time of the heating monitoring timer is set in step S1, and the total number determination timer is set in step S2. Start.
[0073]
When the total number determination timer is started in step S2, the process proceeds to step S3, in which the work coils 7, 8 are turned on with a 70% output and a high duty ratio of 9/16, and the heat retention heater 11 is turned on with a high duty ratio of 10/16. Further, the temperature of the rice cooker is rapidly increased to 93 ° C. by controlling the lid heater 17 to ON at a relatively high duty ratio of 5/16, and the rice is sterilized by heating the rice. Then, the remaining amount of rice in the rice cooker is determined by measuring the temperature rise time at that time, and the maintenance time of the subsequent maintenance process and the control temperature at the time of the third target heat retention temperature control are determined.
[0074]
Thereafter, the process proceeds to step S4, where it is determined whether or not the set time of 420 seconds set in step S1 has elapsed. If the determination is affirmative, the process proceeds to step S6, where the timer count for the total number determination is terminated, and the flow proceeds to step S6. To end. Then, in the case of a negative determination that the set time has not yet elapsed in step S4, the process proceeds to step S5, and it is determined whether the temperature of the inner pot is equal to or higher than 92 ° C., and in the case of a negative determination, the process returns to step S3 to further increase the temperature. Heating is continued. In the case of an affirmative determination that the temperature of the inner pot becomes 92 ° C. or higher in step S5, the process proceeds to step S6, in which the timer count for the total number determination ends, and this flow ends.
[0075]
When the flow of FIG. 7 is completed in this way, the process returns to FIG. 4 again, proceeds to step S12, and the second maintenance process is performed. The second maintenance process in step S12 is a process in a second maintenance interval, and is performed according to a subroutine flowchart shown in FIG. That is, when the second maintenance process starts, the process proceeds to step S1, and the timer count value of the total number determination counted in step S6 of FIG. 7 is read in step S1.
[0076]
When the timer count value for the total number determination is read in step S1, the process proceeds to step S2, where the maintenance time according to the timer count value is determined. That is, when the timer count value is small, the amount of the remaining rice is determined to be the minimum amount, the maintenance time of 5 minutes is determined, and when the timer count value is medium, the amount of the remaining rice is determined to be medium, and the maintenance time is determined. The time of 20 minutes is determined, and if the timer count value is large, the amount of the remaining rice is determined to be the maximum amount, and the maintenance time of 30 minutes is determined.
[0077]
Then, when the maintenance time is determined, the process proceeds to step S6, and it is determined whether the amount of rice is greater this time than in the previous time. This step is for preventing the microcomputer from erroneously determining that the amount of rice has increased. As a result, in the case of an affirmative determination, it is determined that the microcomputer has made an erroneous determination, the process proceeds to step S7, and since the previous rice amount is correct, the previous data is used, and the determination in the next step, step S9, is performed. . However, if a negative determination is made in step S6, a correct determination has been made, and the flow advances to step S8 to update the data to the current data.
[0078]
Thereafter, the process proceeds to step S9, and after step S9, the maintenance control at the maintenance temperature of 87 ° C. is performed. That is, when the temperature of the inner pan is 87 ° C. or more, the process proceeds to step S10, in which the outputs of the work coils 7, 8 and the heater 11 are turned off, and the process proceeds to step S12. If the temperature of the inner pot has not yet reached 87 ° C. in the negative, the process proceeds to step S11, in which the work coils 7, 8 are turned on with a 70% output, a high duty ratio of 9/16, and a heat retention heater. 11 is controlled at a high duty ratio of 10/16, and the lid heater 17 is controlled at a relatively low duty ratio of 3/16. Thereafter, the process proceeds to step S12, in which it is determined whether the maintenance process time of 5, 20, or 30 minutes has elapsed. If not, the process returns to step S9 and repeats. If it is determined that the flow has been performed, the flow ends.
[0079]
When the flow of FIG. 8 ends, the process returns to FIG. 4 and proceeds to the third heat retention step of the next step S13, where the third target heat retention temperature control is performed. The third target heat retaining temperature control is performed in accordance with the flowchart of FIG. 5, similarly to the first and second target heat retaining temperature controls.
[0080]
That is, when the third target heat retaining temperature control is started, the process proceeds to step S1, in which a set temperature corresponding to the total number selected in step S11 of the main routine of FIG. 4 is set, and the set temperature is set in step S2. Is determined to be high. If the determination in step S2 is low and the remaining amount of rice is low and the set temperature is 69 ° C. or lower, the process proceeds to step S4 and the outputs of the work coils 7 and 8 are turned off.
[0081]
If the set temperature is 70 ° C. or more, such as 70 ° C. when the remaining amount of rice is high in the determination in step S2, and 71 ° C. if the remaining amount of rice is high, the step is performed. Proceeding to S3, the outputs of the work coils 7 and 8 are ON-controlled by a low duty ratio of 1/16 of the 60% output, and then proceed to step S5, where the estimation is obtained according to the flowchart of the room temperature take-in control shown in FIG. Capture the room temperature data that is the value. Of course, the room temperature data, which is the estimated value, is a stable room temperature data during the second warming interval before 2 hours after the start of the second warming process because the room temperature sensor determination prohibition zone is used. After two hours from the start of the second temperature raising step, the data of the second heat retaining step is taken in, and the data is updated every second.
[0082]
After capturing the room temperature data, which is the estimated value in step S5, the process proceeds to step S6, where it is determined whether the captured data is greater than the predetermined value t1 of 39 ° C. Then, the process proceeds to steps S7 and S8, in which the heater heater 11 is turned on at a high duty ratio of 12/16, and the lid heater 17 is turned on at a relatively high duty ratio of 4/16.
[0083]
If the negative determination is made at step S6 that the room temperature is higher than 39 ° C., the process proceeds to step S9, where it is determined whether the room temperature is between 39 ° C. and 57 ° C., which are medium temperatures. As a result, when an affirmative determination is made that the room temperature is an intermediate temperature between 39 ° C. and 57 ° C., the process proceeds to step S10 and step S11, in which the insulated heater 11 is turned on at a high duty ratio of 10/16 and the lid heater 17 is turned on. Are turned on at a low duty ratio of 2/16.
[0084]
Further, when the negative determination is made in step S9 because the room temperature is a high temperature higher than 57 ° C., the process proceeds to step S12 and step S13, in which the heat retention heater 11 is turned on at a high duty ratio of 8/16 and the lid heater 17 is turned on. Is controlled at a low duty ratio of 2/16.
[0085]
Then, when the output of the heating means is determined based on the room temperature data, the third target thermal insulation temperature control in step S13 in FIG. 4 is performed based on the output so that the thermal insulation temperature is determined in advance as a result of the combination determination. While being executed, the third target heat retention temperature control is continued until the heat retention control ends. As a result, even if the temperature is kept for a long period of time, germs are generated in the rice, and the smell, yellowing, or dryness is suppressed, and the convenience of the rice cooker is improved.
[0086]
The present invention is not limited to the configuration of the above-described embodiment. For example, a work coil is adopted as a heating means of the inner pan 4, but it goes without saying that this may be changed to a general electric heater. Of course, other than that, the design can be appropriately changed without departing from the gist of the invention.
[0087]
【The invention's effect】
The invention according to claims 1 and 2 includes an inner pot, a heating unit that heats the inner pot, a heating control unit that controls a heating state of the heating unit, and a temperature sensor that detects a temperature of the inner pot. In the rice cooker provided, a room temperature sensor for detecting the indoor temperature is provided, and the heating control at the time of keeping the temperature after the rice cooking process is performed by using the temperature data before the rice heating detected by the room temperature sensor for a predetermined time at the time of keeping the temperature. That is, after a lapse of a predetermined time during which the temperature detected by the room temperature sensor at the time of keeping the temperature is stabilized, the temperature is controlled using the temperature data at that time, but the actual room temperature is estimated based on a predetermined threshold value. By doing so, even if the room temperature sensor is affected by the rice cooking temperature at the time of cooking, the temperature can be controlled based on an appropriate room temperature, so that the temperature control can be performed in a state closer to the actual state. Further, the heat retention control in each temperature control section is controlled according to the output corresponding to the room temperature, that is, when the room temperature is low, it is controlled with a large output, and when the room temperature is high, it is controlled with a small output, so that the control can be performed precisely. At the same time, energy consumption can be reduced.
[0088]
Furthermore, even if the room temperature data obtained by inferring the heat retention control in each temperature control section is not significantly different from the actually measured value and is the same as the immediately preceding data, it is not affected by changes in the environment. At the same time, since the data used is stable temperature data, accurate heat control can be performed. By using estimated data, it is not necessary to use a precise sensor or control circuit, so low-cost heat control can be performed. It becomes.
[0089]
According to the third aspect of the present invention, in the case where there is a temperature raising step during the heat retention, the temperature data at the time of stability before the temperature rise is used, in addition to the effects of the inventions according to the first to third aspects. Even if there is a temperature step, the temperature control at the time of stabilization before the temperature rise is used for the next heat retention control, so that accurate control can be performed for a long time without malfunction and the utility value can be greatly enhanced. .
[Brief description of the drawings]
FIG. 1 is a sectional view showing the configuration of a rice cooker according to the present invention.
FIG. 2 is a system block diagram of a control circuit portion of the rice cooker main body.
FIG. 3 is an overall time chart from the rice cooking process to the heat retaining process.
FIG. 4 is a flowchart of a main routine of the content of the heat retention control of the rice cooker according to the present invention.
FIG. 5 is a flowchart of a subroutine of the heat retention control.
FIG. 6 is a flowchart of a subroutine relating to a room temperature data take-in prohibition section of the contents of the heat keeping control.
FIG. 7 is a flowchart of a subroutine relating to temperature rise control of the same heat retention control content.
FIG. 8 is a flowchart of a subroutine related to maintenance control of the heat retention control content.
[Explanation of symbols]
1. Rice cooker 2. Rice cooker body
4 ... Inner pot 7 ... Work coil
8: Corner coil 10: Temperature sensor
11: Heat insulation heater 17: Lid heater
30 ... operation panel 32 ... room temperature sensor
40: microcomputer control unit 45: IGBT drive circuit
46: pulse width modulation circuit 48: inner pot temperature detection circuit
49: Temperature detection circuit 53: Synchronous trigger circuit
54: lid heater drive circuit 56: heat retaining heater drive circuit
100 ... microcomputer control device

Claims (3)

In a rice cooker comprising an inner pot, a heating means for heating the inner pot, a heating control means for controlling a heating state of the heating means, and a temperature sensor for detecting the temperature of the inner pot, the indoor temperature is detected. In addition to the provision of a room temperature sensor, the heating control at the time of keeping the temperature after the rice cooking process is performed using the temperature data before the rice heating detected by the room temperature sensor. A rice cooker that controls heat retention using data, but estimates the actual room temperature based on a predetermined threshold. 2. The rice cooker according to claim 1, wherein the predetermined time is a time when the temperature detected by the room temperature sensor at the time of keeping the temperature is stabilized. 3. 3. The rice cooker according to claim 1, wherein when there is a heating step at the time of keeping the temperature, temperature data at the time of stability before the heating is used.

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