JPH0560731B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rice-cooking heat-retaining jar, and in particular detects a temperature close to the actual rice-cooking temperature to accurately and stably control the rice-cooking process. This invention relates to a rice cooker that performs heat retention control by detecting the temperature of rice close to the actual temperature.

[Conventional technology]

Currently, the rice cooker heating jars on the market are:
It is a combination of an electric rice cooker and a warming jar. Such a rice-cooking heat-retaining jar is provided with a heater and a temperature sensor at the bottom of the inner pot, and rice is cooked by supplying heating power to the heater under control of the temperature sensor. In addition, a heat-retaining heater is provided on the lid of the inner pot or the body of the inner pot to keep the rice warm, and after the rice is cooked, the energization of the heater is controlled to keep the cooked rice warm. This ensures that the cooked rice is always warm when eaten.

Also, with the aim of cooking delicious rice,
A controller equipped with a temperature sensor and a microcomputer measures the temperature of the rice cooking pot, inputs data on the temperature or temperature rise into the microcomputer, determines the rice cooking capacity, and performs appropriate power control according to the rice cooking capacity. A microcomputer-controlled automatic rice cooker has been developed to do this.
An automatic rice cooker that cooks rice under microcomputer control sequentially processes water absorption process, rice cooking capacity determination process, cooking process, boiling maintenance process, first unevenness process, additional cooking process, and second unevenness process under program control of microcomputer. process,
A series of rice cooking process controls such as a heat retention process are performed, rice is cooked in an optimal state, and after the rice cooking control is performed, a heat retention control state is entered. Microcomputer-controlled rice cookers can finely control the rice cooking process through program control, so by being equipped with programs for multiple types of rice cooking control patterns, you can enjoy multi-functional rice cooking, fast-cooking rice, timer reservation cooking, notification of when rice is ready, and washing. It is equipped with various convenient functions such as instant rice cooking. Additionally, a rice cooker that combines a microcomputer-controlled automatic rice cooker and a warming jar has been realized.

[Problem to be solved by the invention]

By the way, in the rice cooking process control of the microcomputer-controlled rice cooker, the temperature is detected by a temperature sensor provided at the bottom of the pot, the rice cooking capacity is determined, and the heating of the rice is controlled according to the determined rice cooking capacity. . The rice cooking capacity is determined by detecting the temperature with a temperature sensor located at the bottom of the pot, and determining the temperature rise gradient at the bottom of the pot, or by determining the transfer rate of heat. The temperature of the inner pot (temperature during rice cooking) cannot be detected, and the rice cooking capacity is determined by approximate temperature detection. In addition, the detected temperature may be inaccurate due to the degree of closeness between the rice cooker and the bottom of the pot, the degree of closeness between the temperature sensor and the bottom of the pot, the influence of the rice cooker installed near the temperature sensor, and the determination of the rice cooking capacity may be inaccurate. The rice becomes unstable, and rice cooking cannot be controlled properly.

The rice cooking capacity is determined by energizing the rice heater with constant power to heat the bottom of the pot, stopping the energization of the rice heater when a predetermined temperature is reached, and measuring the subsequent temperature drop gradient. The amount of heat added to the rice and water through the bottom of the pot due to heating with a constant electric power is transferred to areas other than the bottom of the pot, and the temperature at the bottom of the pot decreases.The temperature drop gradient due to the transfer of this amount of heat is measured. Determine the rice cooking capacity. If the rice cooking capacity (rice + water) is large, the amount of heat transferred will be large and the temperature drop gradient will be large, and if the rice cooking capacity is small, the opposite will occur, so the rice cooking capacity can be determined.

The rice cooking capacity is determined by transmitting the amount of heat from the rice cooking heater from the bottom of the pot to the inner pot of the rice cooking pot, and measuring the temperature drop gradient based on the heat transfer. The rice cooking capacity is determined using the rice cooking heater and temperature sensor. For this reason, the rice cooking capacity determination (combination determination) may be unstable due to the influence of the degree of closeness between the rice cooking heater and the bottom of the pot, the degree of closeness between the temperature sensor and the bottom of the pot, the amount of heat directly conducted from the rice cooking heater to the temperature sensor, etc. There is a possibility that this will happen.

In addition, in the rice cooker, after the rice has been cooked through the rice cooking process control, it shifts to the heat retention control, but the temperature of the rice for the heat retention control performed during the heat retention operation is detected by the temperature sensor installed at the bottom of the pot. Alternatively, the temperature sensor is installed separately on the side of the fuselage. For this reason, for example, when heat retention control is performed using a temperature sensor provided at the bottom of the pot, it is likely to be influenced by the rice cooking heater, and heat retention control cannot be performed appropriately.

In addition, since there are many control parts on the bottom, it is difficult to provide an insulating structure, and the temperature sensor is easily affected by the outside temperature. In addition, the temperature sensor that detects the temperature that performs heat retention control is located at the bottom of the rice cooking jar, so even if the jar lid is opened and the surface of the rice gets cold, this cannot be detected and the heater is not properly heated. It is not possible to control energization and maintain heat.

For this reason, a temperature sensor for heat retention control is separately provided on the side of the body, and the temperature sensor on the side of the body is configured to perform heat retention control. In this case as well, there is a gap between the temperature sensor and the inner pot containing the rice, which slows down the temperature detection and makes it more susceptible to the influence of outside temperature. For this reason, heat retention control cannot be performed more appropriately.

The present invention has been made to solve these problems.

An object of the present invention is to accurately and stably determine the rice cooking capacity in rice cooking process control by detecting a temperature close to the actual rice cooking temperature, and to also detect the temperature of the rice close to the actual warming temperature. The purpose of the present invention is to provide a rice-cooking heat-retaining jar that performs heat-retaining control.

Another object of the present invention is to directly detect the temperature of the pot lid, and based on the detected temperature, control the rice cooking process of the shoulder heat retention heater and rice cooking heater provided at the shoulder of the inner pot, control the pot lid exposure, and keep the temperature warm. The objective is to provide technology that allows accurate control.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

In order to achieve the above object, the rice cooking and heat retaining jar of the present invention includes an inner pot, a rice cooking heater provided at a lower part of the inner pot, a pot lid made of a material with high thermal conductivity that covers the inner pot, and a rice cooking heater provided at a lower part of the inner pot. an outer lid that covers the pot lid with a material with low thermal conductivity, a sensor for detecting the temperature of the pot lid provided on the outer lid at a position in close contact with the pot lid, and a shoulder heat insulator provided on the shoulder of the inner pot. It has a heater, and a control means for controlling the rice cooking process of the shoulder heat-retaining heater and the rice cooking heater based on the output of the pot lid temperature detection sensor,
The control means is characterized in that it includes a rice cooking capacity determining means for determining the rice cooking capacity by detecting the temperature of the pot lid temperature detection sensor.

The rice-cooking heat-retaining jar of the present invention includes an inner pot, a rice-cooking heater provided at the bottom of the inner pot, a pot lid made of a highly thermally conductive material that covers the inner pot, and a pot lid made of a thermally conductive material. An outer lid covered with a low-temperature material, a sensor for detecting the temperature of the pan lid provided on the outer lid at a position in close contact with the pot lid, a shoulder heat-retaining heater provided on the shoulder of the inner pot, and rice cooking using each of the heaters. It has a control means that performs process control and heat retention control based on the output of the pot lid temperature detection sensor, and the control means stops energizing the shoulder heat retention heater when the rice cooking process control ends and the temperature becomes below a predetermined temperature. The invention is characterized in that it includes means for heating the pot lid by heat conduction from the shoulder heat-retaining heater to control the heat retention.

The pot lid temperature detection sensor is characterized in that it protrudes downward from the inner surface member of the outer lid and is fixed in an elastic sensor case that tightly contacts the pot lid. The pot lid is made of a material with high thermal conductivity and has a shape that touches the inner pot at the shoulder and covers the inner pot, and further,
Corresponding to the position of the sensor case that protrudes downward,
It is characterized by an annular rib with a flat top surface.

[Effect]

According to the above means, the rice cooking heater is provided in the lower part of the inner pot, and the temperature sensor is arranged in a position in close contact with the pot lid. The inner pot is covered with a pot lid made of a material with high heat conductivity, and the pot lid is covered with an outer container made of a material with poor heat conduction. The temperature sensor disposed in close proximity to the pot lid is directly thermally coupled to the pot lid, and performs temperature detection from the pot lid for controlling the rice cooking process. Then, a temperature signal is obtained by the temperature sensor, and the control means controls energization of the heater based on the obtained temperature signal to perform rice cooking process control and heat retention control.

This allows the temperature sensor to detect temperatures close to the actual rice cooking temperature using the entire pot lid, which has high thermal conductivity, as the rice cooking temperature detection surface, making it possible to accurately and stably control the rice cooking process. can. Further, even during the heat-keeping operation, the temperature of the rice close to the actual heat-keeping temperature can be detected to perform heat-keeping control.

That is, the control means controls energization of the rice cooking heater provided at the lower part of the inner pot, and rice cooking process control is started. A temperature signal serving as a control signal for controlling the rice cooking process is detected by a temperature sensor placed closely to the pot lid. The inner pot is covered with a pot lid made of a material with high heat conductivity, and the pot lid is covered with an outer container (outer lid) made of a material with poor heat conductivity to insulate it. Therefore, there is no influence of outside temperature, and temperature detection accuracy is increased. A pot lid made of a highly thermally conductive material (for example, aluminum) follows the temperature changes of the rice and water in the inner pot, and even if there is a sudden temperature change, The temperature will be almost the same as that of the rice. For example, to determine the rice cooking capacity, when the rice heater at the bottom of the pot is heated at a constant power, the heat from the rice cooker is transmitted from the bottom of the pot, then to the rice and water, and then the temperature in the upper space of the inner pot is determined. to rise. Naturally, the temperature increase gradient is inversely proportional to the cooking capacity of the rice and water in the inner pot; when the rice cooking capacity is large, the degree of temperature rise is small, and when the rice cooking capacity is small, the temperature rise is large. The degree of this temperature rise is measured by a temperature sensor provided on the pot lid, and the rice cooking capacity is determined. In this case, since the rice-cooking heater and the temperature sensor are separated, the temperature sensor is not affected by the temperature of the rice-cooking heater and cannot detect the true temperature rise (temperature rise at the actual rice-cooking temperature) in the inner pot. I can do it. Thereby, accurate rice cooking capacity can be determined. Furthermore, by performing heat retention control in accordance with the temperature signal detected from this temperature sensor, the actual temperature of the rice can be detected and heat retention control can be performed, and appropriate heat retention control can be performed.

In addition, the outer container that covers the pot lid is made of a material with low thermal conductivity (plastic, glass wool, etc.), so the outside temperature has little effect on the temperature sensor, and the outside heat has no effect on the sensor. , to prevent a negative influence on the determination of the amount of rice to be cooked. Furthermore, the outer container made of a material with low thermal conductivity contributes to energy savings in cooking power, increased heat retention performance, and energy savings in heat retention power.

〔Example〕

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

FIG. 1 is a cross-sectional view of a rice-cooking heat-retaining jar according to an embodiment of the present invention. In FIG. 1, 1 is the rice cooker main body, 2 is the lid of the rice cooker main body 1, and 3 is the main body of the rice cooker main body 1. The main body part 3 includes an inner pot 4,
An inner pot storage container 5 that stores the inner pot, a rice cooking heater 6 on the bottom of the inner pot, a shoulder ring 7 provided on the shoulder of the inner pot storage container, and a heat-retaining heater ( An outdoor heater (hereinafter referred to as an open heater) 8, a heat retention heater provided in the body of the inner pot storage container (a heat retention heater for heat retention control; hereinafter referred to as a body heat retention heater) 9, a microcomputer, etc. A built-in control unit 10 and the like are provided inside. In addition, the shoulder of the inner pot 4 has a pot lid 4a.
The upper part is covered with a pot lid 4a. Pot lid 4a
is formed by molding a material with high thermal conductivity, such as aluminum. A temperature sensor 25 for the pot lid part is provided, which is housed in a sensor case (24; FIG. 3) that is placed in close contact with the pot lid 4a. 2
9 is a temperature sensor provided at the bottom of the inner pot. Further, 11 is a function display selection operation unit.

The function display selection operation unit 11 is the rice cooker main body 1.
The function display selection operation unit 11 includes a plurality of operation key switches, light emitting diodes for displaying various statuses, and a 7-segment character display for displaying the time, as will be described later. is provided. The operation key switches include an hour key switch, a minute key switch, a reservation key switch, a menu key switch, a start key switch, and a cancel key switch.

FIG. 2 is a front view showing the panel surface of the function selection operation unit. In FIG. 2, 12 is a character display, for example, a 4-digit numerical display liquid crystal module that displays the characters of each display digit in 7 segments. The character display 12 displays the time as well as the reserved time for reserved rice cooking. 13a is a key switch for operating the hour digit; 13b is a minute key switch for operating the minute digit; 13c is a reservation key switch for instructing a reservation;
13d is a menu key switch for instructing the rice cooking menu; 13e is a start key switch for instructing the start of rice cooking operation or the start of reserved rice cooking operation; 1
3f is a cancel key switch for canceling each operation. Further, 14 is a status display section that displays the operation mode. The status display section 14 is provided with a plurality of light emitting diodes that display various statuses of the rice cooking and warming jar. As the status to be displayed,
In order to display the reservation mode distinction, rice cooking menu type of rice cooking control, and heat retention mode distinction, "Reservation 1", "Reservation 2", "White rice",
The various statuses are displayed by lighting up the light-emitting diodes labeled ``Quick Cook'', ``Rice Cook'', ``Rice Rice'', ``Brown Rice'', ``Porridge'', ``Keep Warm'', and ``Keep Freshly Cooked Warm''.

FIG. 3 is a sectional view of the main parts showing the mounting structure of the temperature sensor disposed closely to the pot lid. As shown in FIG. 3, the temperature sensor 25 is installed in a sensor case 24 that is placed in close contact with the top surface of the pot lid 4a.
It is fixed within. The pot lid 4a is made of a material with high thermal conductivity, and the sensor case 24
Similarly, it is made of a material with high thermal conductivity. Further, the sensor case 24 has an elastic structure that protrudes downward from the inner surface member of the outer lid and comes into close contact with the pot lid 4a. This is sensor case 2
This can be realized by forming 4 from an elastic material or by having a structurally elastic structure. The temperature sensor 25 is fixed to a sensor board unit 25a made of a material with low thermal conductivity, the temperature sensor 25 is fitted into a groove at the bottom of the sensor case 24, and is fixed to the sensor case 24 integrally with the sensor board unit 25a. . In order to fix the sensor board unit 25a to the sensor case 24,
An annular rib is provided on the inner surface, and the temperature sensor 25 is fixed by force-fitting the sensor substrate unit 25a into the sensor case 24 beyond the annular rib. Further, a heat insulating material 2b is provided between the sensor case 24 containing the temperature sensor 25 and the outer lid 2a, and the structure is such that the temperature sensor 25 is prevented from being affected by the outside temperature.

In this way, the sensor case 24 (temperature sensor 2
5) is disposed in close proximity to the pot lid 4a, and the temperature sensor 25 detects the actual temperature of the rice in the cooking state (rice and By detecting the temperature of the water, the temperature of the cooked rice can be accurately detected. Therefore, the rice cooking process can be appropriately controlled by microcomputer control. Furthermore, during the heat-keeping operation, the temperature of the rice can be accurately detected, so that heat-keeping control can be performed appropriately.

FIG. 4 is a block diagram showing the configuration of the main parts of a control unit using a microcomputer.
In FIG. 4, 6 is a rice cooking heater, 8 is an open heater, 9 is a shoulder heat retention heater, 10 is a control unit,
11 is a function display selection operation unit, 25 is a lid temperature sensor (hereinafter referred to as the lid sensor) provided on the pot lid, and 29 is a bottom temperature sensor provided on the bottom of the inner pot (hereinafter referred to as the bottom). (referred to as a sensor). As mentioned above, the function display selection operation unit 11 includes a 7-segment character display 12, operation key switches 13, 13a to 13f,
A light emitting diode 14 of a status display section 14 is provided. Further, 15 is a commercial AC power supply, and 16 is a temperature fuse. The control unit 10 includes a relay 17 for switching between rice cooking mode and warming mode.
Triack 1 that controls energization of rice cooking heater 6
8, a triax 19a that controls the energization of the exposed heater 8, a triax 19b that controls the energization of the torso heat-retaining heater 9, a microcomputer 20, a clock mechanism 21, a buzzer 22, and the like. Temperature sensor (lid sensor) 2 provided on the lid of the inner pot
5 is composed of a thermistor and the like. In addition, a bottom temperature sensor (bottom sensor) 29 provided at the bottom of the pot
Similarly, it is composed of a thermistor or the like. These temperature sensors detect temperature and output electrical signals corresponding to the temperature. The electrical temperature signal is input to the analog/digital conversion port of the microcomputer 20. Microcomputer 2
0 has a built-in processing unit CPU, memory RAM, program memory ROM, input port with analog/digital conversion function, multiple input ports that accept key switch input, output ports that output control output signals and display control signals, etc. According to the program stored in the program memory, a predetermined output signal is output from the output port in response to the input from the input port. That is, the microcomputer 20 includes temperature sensors (lid sensor 25, bottom sensor 29), clock mechanism 21,
It receives input from the operation key switch 13, performs a series of processes according to the built-in processing program, and sends a control signal to a triator etc. that controls the energization of the heater. A lighting control signal is sent to the light emitting diode of the display section 14. In addition, the clock mechanism 21
The time signal is input to the microcomputer 20, and the time is displayed on the character display 12, and the time signal is input to the microcomputer 20 as a signal for determining the reservation time when performing timer reservation rice cooking.
It is input to 0 and used.

Next, the operation of the rice cooking/warming jar configured in this way will be explained.

FIG. 5 is a flow chart showing an outline of the overall control flow of the microcomputer. Fifth
This will be explained with reference to the figures.

When the power is turned on, in step 31,
Performs preprocessing for rice cooking control. In the preprocessing for this rice cooking control, initialization processing is performed to reset various internal registers, timers, etc. of the microcomputer.
Setting processing of rice cooking operation instruction data such as rice cooking menu setting and rice cooking reservation time setting is performed, and then when the start key switch is turned on (or when the reserved time comes in the case of reserved rice cooking), the process starts from step 32. Perform processing. In step 32, in order to control rice cooking, the relay is turned on and the rice cooking heater circuit is turned on. Next, the rice cooking process control in step 33 is performed. As a result, a rice cooking operation is performed to cook the rice. When the rice cooking operation is completed, in step 34, the relay is turned off, the rice cooking heater circuit is turned off, and a heat retention control mode is set in which heat retention control is performed to keep the cooked rice warm. In the heat retention control mode, processing from step 35 is performed.

In this heat retention control mode, normal heat retention control is performed in step 35, and in the next step 36,
Determine whether the temperature is abnormal. If the temperature is abnormal, error processing such as abnormality notification and abnormality display is performed in step 37, and the entire process is terminated.
If the temperature is not abnormal in step 36, the process returns to step 35 and the normal heat retention control is repeated.

Next, the operation of the rice cooking control process controlled by the microcomputer configured as described above will be specifically explained.

When the desired amount of rice and the appropriate amount of water are put into the inner pot 4 and the start key switch is turned on, the microcomputer 20 of the control unit 10 starts the processing steps of the rice cooking program stored in the program memory ROM therein. Then, power control for heating in the rice cooking process is started. At this time, the microcomputer 20 controls the lid sensor 2.
Convert the voltage output from 5 into a digital quantity from the input port A/D of the analog/digital conversion function, perform the process of converting it to temperature, judge the input temperature, and calculate various values from the temperature judgment result. The rice cooking process will be controlled. To explain the outline of this rice cooking process, in the rice cooking process, a water absorption process is performed in which the heating power is reduced and the rice absorbs water. Next, the heating power is increased to rapidly raise the temperature to perform a boiling step, and then a boiling maintenance step to maintain boiling. As this boiling maintenance process continues, the rice absorbs enough water and the moisture at the bottom of the inner pot disappears, and when a predetermined temperature, for example 130°C, is reached, this temperature is detected by the bottom sensor 29 and the microcomputer 20 heats the rice. The boiling maintenance process is completed by turning off the heater. Next, for a predetermined period of time, a first steaming step, a first additional cooking step, a second steaming step, a second additional cooking step, etc. are performed, and finally the warming step is reached and the rice cooking step is ended. When the rice cooking process control is finished, the next step is to move on to the warming process control.

FIGS. 6a and 6b are diagrams showing examples of rice cooking temperature curves showing temperature changes in the inner pot 4 when rice cooking process control and heat retention control are performed under the control of such a microcomputer. Chapter 6a
In the figure, the area indicates the water absorption process, the area indicates the cooking process including the rice cooking capacity determination process, and the area indicates the boiling maintenance process. Further, the area indicates an uneven process including an additional cooking process. The region cooking process is a process in which the heating power is increased to rapidly raise the temperature, bring it to a boil, and continue to the boiling maintenance process. This step includes a step of determining the rice cooking capacity (combination determination), and the rice cooking capacity is determined by this rice cooking capacity determining step. This is lid sensor 2
5, the actual temperature of the cooked rice and water contained in the inner pot (rice cooking pot) is detected to determine the rice cooking capacity. Then, in the next boiling maintenance step, heating power is controlled to be appropriate according to the determined rice cooking capacity to maintain boiling appropriately. In the example of the rice cooking temperature curve in Fig. 6a, the solid line shows an example when the rice cooking process is controlled in the normal rice cooking mode.
An example in which the rice cooking process is controlled in the timer reservation rice cooking mode is shown by a dashed dotted line.

Moreover, FIG. 6b shows temperature changes in the temperature of the inner pot and the temperature of the lid during the heat retention control.

When the rice cooking process control is completed, next, the process moves to heat retention control. In this heat retention control, as shown in FIG. 6b, when the rice cooking operation for cooking rice ends at time t1, a heat retention operation mode is entered in which heat retention control is performed. At time t1 immediately after rice cooking, the temperature of the rice is sufficiently high, so even in the heat retention control mode, energization control of the torso heat retention heater and shoulder heat retention heater is not performed. The temperature of the rice decreases and eventually reaches 72℃ at t2.
When the temperature of the rice drops below 71 degrees Celsius, it detects this and first starts the energization control of the shoulder heat-retaining heater to heat the pot lid by heat conduction. In addition to controlling the energization of the body heat-retaining heater, the heat-retaining heater is also energized to perform normal heat-retaining control that maintains the heat-retaining temperature in the rice-cooking heat-retaining jar at 71°C. While such normal heat retention control is being performed, heat retention control is always performed so that the shoulder heat retention heater is kept at a higher temperature than the torso heat retention heater. Furthermore, when controlling the energization of these heat-retaining heaters, the shoulder heat-retaining heater is always energized earlier than the torso heat-retaining heater, and the heat-retaining control is performed.

As a result, the shoulder heater is energized so that it always generates a higher amount of heat than the surrounding area, and the rice cooking jar is kept warm, so the amount of heat generated from the shoulder heater is conducts heat to prevent dew from dripping on the pot lid. That is, as shown in FIG. 6b, the temperature of the rice and the lid part changes when heat retention control is performed, so that the temperature of the lid part is always kept high, and dew is prevented from dripping from the lid.

FIGS. 7a, 7b, and 7c are flowcharts showing the processing flow of the control operations of the rice cooking process, boiling maintenance process, and additional cooking process including the rice cooking capacity determination process performed by the microcomputer.
Moreover, FIG. 7d is a flowchart showing the processing flow of heat retention control.

First, reference is made to FIG. 7a. When the water absorption process is completed, the cooking process begins, and processing starts from step 40. In step 40, the rice cooking heater is turned on at full output HW. Next, in step 41, it is determined whether the temperature of the inner pot has reached a predetermined temperature t0°C, and if it has not reached t0°C, in step 40, the full output HW of the rice cooking heater is continued to be energized. When the temperature of the inner pot reaches t0℃, the power to the rice cooking heater is turned off in step 42, and the heating is continued for a predetermined time (S) in step 43.
It is determined whether S seconds have elapsed or not, and the energization-off state of the rice cooking heater in step 42 is continued until S seconds have elapsed. When the rice cooking heater is turned off for S seconds, a time counting process corresponding to the rice cooking capacity is started, and in step 44, the T1 counter starts counting the time. Next, in step 45, the rice cooking heater is turned on again at full output HW. Then, in step 46, it is determined whether the temperature of the inner pot has reached a predetermined temperature t3°C, and if it has not reached t3°C, the full power energization of the rice cooking heater in step 45 is continued. In other words, the temperature of the inner pot is detected in step 46, and the rice cooking heater continues to be energized until the temperature of the inner pot reaches t3℃, and the T1 counter continues counting, until the temperature of the inner pot reaches t3℃. When the temperature reaches ℃, the process proceeds to the next step 47 and the counting operation of the T1 counter is stopped. Temperature detection in these processing steps is performed by the lid sensor 25.

The series of steps up to now are steps for determining the rice cooking capacity.

The manner in which the temperature of the rice cooker overruns when the heating power is turned off when the temperature of the rice cooker reaches a constant temperature t0°C differs depending on the difference in rice cooking capacity. Therefore, after heating to a constant temperature t0° C., the heating power is turned off and the temperature of the rice cooker after a certain period of time (S seconds) has elapsed varies depending on the difference in rice cooking capacity.
Therefore, when a certain temperature t0℃ was reached, the heating power was turned off for a certain period of time (S seconds), after which the heating power was turned on again and time counting was started, until the judgment end temperature t3℃ was reached. By the way, stop counting the time. By stopping this time counting, the counted time at that time is proportional to the rice cooking capacity, and the rice cooking capacity can be determined. In other words, the count value by the T1 counter is proportional to the rice cooking capacity.

Next, in steps 48, 52, and 56, the count value of the T1 counter is determined, and each count value (cooking rice capacity) is determined.
Depending on the content, processing for controlling rice cooking power is performed.
In this rice cooking power control, heating power is controlled by on/off control in which the heater is repeatedly turned on and off at regular intervals.

That is, first, in step 48, it is determined whether the content of the T1 counter is less than or equal to a predetermined value m1. If the content of the T1 counter is not less than m1, proceed to step 52, and the content of the T1 counter is
Determine whether m1<T1≦m2. If the contents of the T1 counter are not m1<T1≦m2, the process advances to step 56, and the contents of the T1 counter are not m2<T1≦m2.
Determine whether T1≦m3.

In step 48, the content of T1 counter is m1
In the following cases, the process advances to step 49 to determine whether a predetermined waiting time of ta seconds has elapsed. If ta seconds have passed, turn on the rice cooker in step 50.
In step 51, heating power control is performed to turn on the insulating heater at 5/14. Then, the process proceeds to step 63, where it is determined whether or not timer rice cooking is being performed. In the case of normal rice cooking, which is not timer rice cooking, the rice cooking process is controlled with the cooking temperature set at 130° C. according to the processing flow that passes through the determination step of step 64. In the case of timer rice cooking, if it is determined in step 63 that the rice is timer cooked, the processing flow goes through the determination step in step 65, and the cooking temperature is set to 120°C, which is lower than the normal cooking temperature. Controls the rice cooking process. These cooking temperatures are 130℃,
The temperature of 120° C. is detected by a bottom sensor 29 provided at the bottom of the inner pot. That is, in the case of normal rice cooking, it is determined in step 64 whether the temperature of the inner pot detected by the bottom sensor 29 is below 130°C, and if it is below 130°C, the process returns to step 48. Repeat the process from Further, in the determination process of step 64, if the temperature of the inner pot exceeds 130°C, the cooking process has ended, so step 66 (which controls the shading process and additional cooking process of the next rice cooking process) Proceed to the process in FIG. 7b). In addition, in the case of timer rice cooking, step 63
The process then proceeds to step 65, where it is determined whether the temperature of the inner pot detected by the bottom sensor 29 is below 120°C. If the temperature is below 120°C, the process returns to step 48 and the process from step 48 is repeated. In addition, in the judgment process of step 65, if the temperature of the inner pot exceeds 120℃,
Since the rice-cooking process has been completed, the process proceeds to step 73 (FIG. 7c) in order to control the unevenness process and additional cooking process of the next rice-cooking process.

On the other hand, if the content of the T1 counter is m1<T1≦m2 in step 52, then step 53 is reached.
The process proceeds to determine whether a predetermined waiting time of tb seconds has elapsed. If tb seconds have passed, step
In step 54, the rice cooking heater is turned on at 9/14, and in step 55, heating power control is performed to turn on the warming heater at 5/14. Then, the process proceeds to step 63, where it is determined whether or not timer rice cooking is being performed. If the rice is not timed cooked, the rice cooking process is controlled by setting the cooking temperature to 130° C. according to the processing flow that passes through the determination step of step 64.
In addition, in the case of timer rice cooking, the cooking temperature is determined by the processing flow that passes through the judgment step of step 65.
The rice cooking process is controlled at 120℃. These are T1
The same is true for ≦m1.

Further, in step 56, if the content of the T1 counter is m2<T1≦m3, then step 57 is performed.
The process proceeds to determine whether a predetermined waiting time of tc seconds has elapsed. If tc seconds have elapsed, the step
Turn on the rice cooker at 58 and turn on the rice cooker at 12/14, step 55
Controls the heating power to turn on the heat retention heater at 2/14. Next, the process proceeds to step 63, where it is determined whether or not timer rice cooking is being performed. If the rice is not cooked on a timer, step
The rice cooking process is controlled at a cooking temperature of 130°C using a processing flow that passes through 64 judgment steps. In addition, in the case of timer rice cooking, the cooking temperature is determined by the processing flow that passes through the judgment step of step 65.
The rice cooking process is controlled at 120℃. These are the same as the case of T1≦m1 and the case of m1<T1≦m2 described above.

Furthermore, in step 56, if the content of the T1 counter is not m2<T1≦m3, the process proceeds to step 60, where it is determined whether a predetermined waiting time of td seconds has elapsed. If td seconds have elapsed, heating power control is performed to turn on the rice cooking heater at 12/14 in step 58 and turn on the warming heater at 2/14 in step 55. Next, the process proceeds to step 63, where it is determined whether or not timer rice cooking is being performed. If the rice is not timer-cooked, as described above, the rice-cooking process is controlled by setting the rice-cooking temperature to 130° C. according to the processing flow that passes through the determination step of step 64. In addition, in the case of timer cooking,
The rice cooking process is controlled with the cooking temperature set at 120° C. according to the processing flow that passes through the judgment step of step 65. In the case of T1≦m1 mentioned above, m1<
This is the same as the case where T1≦m2 and the case where m2<T1≦m3.

In this way, in the case of normal rice cooking, the steps
At step 64, it is determined whether the temperature of the inner pot detected by the bottom sensor 29 is below 130°C, and if it is below 130°C, the process returns to step 48 and the process from step 48 is repeated. In addition, if the temperature of the inner pot exceeds 130°C in the determination process of step 64, the cooking process has ended, and step 66 (which controls the shading process and additional cooking process of the next rice cooking process) Proceed to the process in FIG. 7b). In the case of timer rice cooking, the process proceeds from step 63 to step 65. In step 65, it is determined whether the temperature of the inner pot detected by the bottom sensor 29 is below 120°C, and if it is below 120°C. Then, the process returns to step 48 and the process from step 48 is repeated. In addition, in the judgment process of step 65, if the temperature of the inner pot exceeds 120°C, the cooking process has ended, and the next step is to control the shading process and additional cooking process. 73 (Figure 7c)
Proceed to processing.

For regular rice cooking (not timer cooking), the temperature of the pot is
When the temperature exceeds 130℃, the cooking process is over and the step
Proceed to 66.

Continuing with reference to Figure 7b, the steps
At step 66, all heaters are turned off, and the next rice cooking process, which is the unevenness process and the additional cooking process, is controlled. In the next step 67, it is determined whether 12 minutes have elapsed. If 12 minutes have not elapsed, in the next step 68,
Determine whether the temperature of the pot is below 110°C.
If it is not below 110°C, the rice cooking heater is turned off in step 71, the warming heater is turned off in step 72, and the process returns to step 67. Then, in step 67, the process of determining whether 12 minutes have elapsed is performed again. In addition, if it is determined in step 68 that the temperature is 110℃ or lower, in step 69 the rice cooking heater is turned off to 2/14
At step 70, the insulating heater is turned on at 12/14 to perform heating, and the process returns to step 67. Then, in step 67, the process of determining whether 12 minutes have elapsed is performed again, and these processes are repeated until the 12 minutes have elapsed. Once the 12 minutes have passed, the rice cooking will end. In this way, the temperature of the pot remains at 110℃ for 12 minutes after the cooking is finished.
It is determined whether or not the condition is below, and the unevenness process or the additional cooking process is controlled.

In other words, for 12 minutes after the cooking process is finished and the temperature of the pot begins to drop, the heater is turned off and the steaming process is continued until the temperature of the pot reaches 110℃ according to the signal from the temperature sensor. When the temperature drops below 110°C, the rice cooker and heat-retaining heater are heated with a small heating power to perform the additional cooking process. In the case of normal rice cooking, this additional cooking process is controlled at a temperature of 110°C, as described above. but,
As explained next, in the case of timer rice cooking, the additional cooking process is controlled at a temperature of 115° C., which is higher than the normal additional cooking temperature.

Next, the additional cooking process in the case of timer rice cooking will be explained. In the case of timer cooking, as described above, when the temperature of the pot exceeds 120°C, the cooking process is terminated and the process starts from step 73. This process is basically the same as for regular rice cooking, but
In this case, the additional cooking temperature is increased,
Performed at a temperature of 115°C.

Continuing with reference to Figure 7c, the steps
At step 73, all heaters are turned off, and control of the next rice cooking process, ie, the unevenness process and the additional cooking process, is continued. In this case, first, in the next step 74, it is determined whether 12 minutes have elapsed. If 12 minutes have not elapsed, in the next step 75, it is determined whether the temperature of the pot is below 115°C. 115℃
If it is not the following, the rice cooking heater is turned off in step 78 and the unevenness process is performed, but in the next step 79 the warming heater is turned on at 12/14 to prevent the temperature from dropping. Then, return to step 74. In step 74, processing is performed again to determine whether 12 minutes have elapsed. If it is determined in step 75 that the temperature is 115°C or lower, in step 76 the rice cooking heater is turned on at 2/14, and in step 77 the rice heating heater is turned on at 12/1.
Turn on at step 4 to perform additional cooking, and then step
Return to 74. Then, in step 74, the process of determining whether 12 minutes have elapsed is performed again, and these processes are repeated until the 12 minutes have elapsed.

Similarly, in the case of timer rice cooking where rice is cooked at a low temperature (120°C), the additional cooking process is controlled for 12 minutes after the rice is finished cooking. In this additional cooking, it is determined whether or not the temperature of the pot is 115° C. or lower, which is higher than the normal temperature of 110° C., and the varnishing step or additional cooking step is controlled. After controlling such a cooking process, a scouring process, and a re-cooking process, and finishing the rice cooking, control of the warming process is started.

The timer mechanism in this rice cooker is
Since a well-known method is used, no particular explanation is given here. A timer mechanism is provided in the control program of the microcomputer that controls rice cooking, and this timer mechanism is used to process the setting of the timer reservation time and constantly monitor the set reservation time.
When the reserved time is reached, the rice cooking operation is started. Identification of whether rice is timer reservation rice cooking or normal rice cooking is performed by, for example, providing a flag bit indicating that the rice cooking mode is timer reservation rice cooking mode.

When the rice cooking process control is completed, the process moves to the heat retention control process. Next, the heat retention control process will be explained with reference to the flowchart of FIG. 7d.

When the rice is finished cooking and the control of the rice cooking process is completed, the next step is to move on to the heat retention control process. When the heat retention control process is started, first, in step 90, the heat retention LED (light emitting diode) is turned on to indicate that the operation has entered the heat retention operation mode, and in step 91, the rice cooking heater is turned off. Next, in step 92, data from the lid sensor 25 is read to determine whether the temperature of the inner pot is below 72°C. If the temperature is not below 72°C, the shoulder heater 8 is turned off in step 93, the torso temperature heater 9 is turned off in the next step 94, and the process returns to step 90 to perform the processing from step 90. This process from step 90 to step 94 is repeated until the temperature of the inner pot falls to 72°C or less. Further, in the determination process of step 92, if it is determined that the temperature of the inner pot is 72°C or lower, the process proceeds to step 95, and furthermore, the temperature detected by the lid sensor 25 is 72°C or lower.
Determine whether the temperature is below ℃. If the temperature is not below 71 degrees Celsius, that is, if the temperature is between 72 degrees Celsius and 71 degrees Celsius, the process proceeds to step 96, in which the shoulder heater is turned on, and in the next step 97, the torso heater is turned off. , the process returns to step 90 and the processing from step 90 is repeated. In addition, if it is determined in the determination process of step 95 that the temperature is 71°C or less,
Proceed to step 98, and in step 98, first,
The shoulder heater is turned on, and in the next step 99, the torso heater is turned on. Then, the process returns to step 90 and the processing from step 90 is repeated. In this way, the temperature of the inner pot is detected and determined, and the energization of each heat-retaining heater is controlled according to the temperature, thereby performing heat-retaining control in the rice-cooking heat-retaining jar.

In this way, the heat retention control is performed by detecting the substantial temperature of the inner pot using the lid sensor 25. In this case, the control temperature of the shoulder heater is set high to perform heat retention control, and the heat generated from the heater is quickly conducted to the lid part at the top of the rice cooker, where the temperature decreases quickly. It performs a heat retention operation at a high temperature and prevents dew from dripping from the lid part during the heat retention operation. By raising the heat retention temperature at the top of the rice cooker during the heat retention operation, and keeping the heat retention temperature at the bottom of the rice cooker warm without increasing it, this prevents moisture from evaporating from the rice and prevents browning, which is the discoloration of rice. .

As explained above, in the rice cooking and heat retention jar of this embodiment, the temperature sensor (lid sensor) provided in the lid part is used to determine the rice cooking capacity, which requires particularly high accuracy, in the rice cooking process control. This is done by detecting the temperature of the state, and also for heat retention control.
A lid sensor that can detect the actual temperature at which the rice is kept warm detects the temperature and performs heat retention control. The determination of the cooking temperature in the rice cooking process control here is performed by the bottom sensor, but this determination may also be performed by the lid sensor.

Next, another example of the embodiment of the rice cooking/warming jar according to the present invention will be described.

FIG. 8 is a sectional view of a main part showing another example of a mounting structure for a temperature sensor (lid sensor) disposed in close contact with a pot lid. As shown in FIG. 8, in this example, a temperature sensor (lid sensor) 25 is installed in a sensor case 2 that is placed in close contact with the top surface of the pot lid 4a.
6 and is fixed in one piece. The pot lid 4a is made of a material with high thermal conductivity, and the sensor case 26 is also made of a material with high thermal conductivity. Further, the sensor case 26 is disposed at a position protruding downward from the inner surface member 2c of the outer cover 2a,
It has an elastic structure that allows it to come into close contact with the pot lid 4a.
This is realized by forming the sensor case 26 from an elastic material, or by using a spring structure as the mounting structure, for example, to have a structurally elastic structure. The temperature sensor 25 is fitted into and fixed to a support provided at the bottom of the sensor case 26, and is integrally fixed to the sensor case 26 with resin or the like. In addition, a heat insulating material 2 is provided between the sensor case 26 containing the temperature sensor 25 and the outer cover 2a.
b is provided, and has a structure that prevents the temperature sensor 25 from being affected by the outside temperature.

FIG. 9 is a sectional view of a main part showing still another example of a mounting structure for a temperature sensor disposed in close contact with a pot lid. As shown in FIG. 9, in this example, in order to improve the adhesion between the temperature sensor 25 provided on the lid and the pot lid 4b, and to further increase the degree of thermal coupling, the pot lid 4b has a lower part. An annular rib 27 having a flat upper surface is formed in correspondence with the position of the protruding sensor case 24. The mounting structure of the temperature sensor 25 and the sensor case 24 shown in FIG. 9 is similar to that described above (FIG. 3). The pot lid 4 is formed to correspond to the position where the sensor case 24 is disposed on the outer lid inner surface member 2c.
The annular rib 27 b comes into close contact with the sensor case 24, improving the reliability of temperature detection. Further, in the same manner as described above, a heat insulating material 2 is provided between the sensor case 24 containing the temperature sensor 25 and the outer cover 2a.
b is provided, and has a structure that prevents the temperature sensor 25 from being affected by the outside temperature, improving the reliability of temperature detection.

By the way, the lid of the pot always gets dirty with so-called "grease" when cooking rice, so it is customary to remove it and wash it with water. In the case where the rice cooking control is performed by detecting the temperature from the pot lid, as in this embodiment, there is a risk that the pot lid may be deformed when the pot lid is removed and washed with water. In this case, if the part that is in close contact with the temperature sensor is deformed, the accuracy and reliability of temperature detection will decrease, so in the example shown in FIG. 9, an annular rib 27 with a flat top surface is formed on the pot lid. In addition to reinforcing the strength against deformation, the flat portion of the upper surface of the annular rib allows the sensor case containing the temperature sensor to come into close contact over a wide area. Furthermore, the protrusion of the annular rib 27 also increases the contact pressure of the sensor case of the temperature sensor, thereby improving the reliability of temperature detection.

As described above, according to the rice cooking and heat retaining jar of the present invention, the temperature sensor (lid sensor) 25 is disposed at a position in close contact with the pot lid 4a, and this temperature sensor 25 allows By detecting the actual temperature of the rice in the cooking state (the temperature of rice and water) through the pot lid 4a made of the material, the actual temperature of the rice in the cooking state can be accurately detected. Therefore, the rice cooking process can be appropriately controlled by microcomputer control. Furthermore, during the heat-keeping operation, the temperature of the rice can be accurately detected, so that heat-keeping control can be performed appropriately.

In addition, since the rice-cooking heater and the temperature sensor that determines the rice-cooking capacity are placed apart, the true temperature rise in the inner pot is not affected by the temperature of the rice-cooking heater's heat, and the pot lid, which has a large surface area and has good heat conduction, can measure the true temperature rise in the inner pot. Since the temperature is measured by receiving it with a member, it is possible to accurately detect the temperature rise and measure the rice cooking capacity.

Although the present invention has been specifically described above based on Examples, it goes without saying that the present invention is not limited to the above-mentioned Examples, and can be modified in various ways without departing from the gist thereof.

〔Effect of the invention〕

As described above, according to the present invention, the rice cooking process control can be accurately and stably achieved by providing the pan lid temperature detection sensor in close proximity to the pan lid and detecting the temperature close to the actual rice cooking temperature. It can be done by
In particular, the pot lid temperature detection sensor is not affected by the temperature of the rice cooking heater and can detect the true temperature rise (temperature rise at the actual cooking temperature) inside the inner pot, so it can accurately determine the rice cooking capacity. can be determined.

In addition, the pot lid temperature detection sensor can detect the temperature of rice close to the actual cooking temperature and the temperature of the rice in the inner pot, and can also detect the temperature of the shoulder heater at the same time. (Because heat conduction from the shoulder heater heats the pot lid and keeps it warm), it is possible to appropriately control the temperature of the shoulder heater.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a rice cooking heat insulating jar according to an embodiment of the present invention, Fig. 2 is a front view showing the panel surface of the function selection operation unit, and Fig. 3 is a sectional view of the rice cooker insulating jar according to an embodiment of the present invention. Figure 4 is a block diagram showing the configuration of the main parts of a control unit using a microcomputer, and Figure 5 shows the overall control flow of the microcomputer. Figures 6a and 6b are a flowchart showing an outline of the process, and Figures 7a and 6b are diagrams showing an example of a rice cooking temperature curve showing temperature changes in the inner pot when rice cooking process control and heat retention control are performed by microcomputer control. 7b, and 7c are flowcharts showing the processing flow of the control operations of the rice cooking process, boiling maintenance process, and additional cooking process including the rice cooking capacity determination process performed by the microcomputer. A flowchart showing the control processing flow, FIG. 8 is a cross-sectional view of the main part showing another example of the mounting structure of the temperature sensor disposed closely on the pot lid, and FIG. FIG. 7 is a cross-sectional view of main parts showing still another example of a mounting structure for temperature sensors arranged closely together. In the figure, 1...the rice cooker body, 2...the lid, 2a...
... Outer lid, 2b... Insulating material, 2c... Outer lid inner surface member, 3... Main body, 4... Inner pot, 4a, 4b...
Pot lid, 5... Inner pot storage container, 6... Rice cooking heater,
7...Shoulder ring, 8...Outdoor heat retention heater, 9...
Body heat retention heater, 10... Control unit, 11...
...Function display selection operation unit, 12...Character display, 13...Operation key switch, 14...Status display unit, 15...Commercial AC power supply, 16...Temperature fuse, 17...Relay, 18, 19a, 19b …
...Triack, 20...Microcomputer, 21...Clock mechanism, 22...Buzzer, 24,
26... Sensor case, 25... Temperature sensor (lid sensor), 27... Annular rib, 29... Temperature sensor (bottom sensor).

Claims (1)

[Scope of Claims] 1. An inner pot, a rice cooking heater provided at the bottom of the inner pot, a pot lid that covers the inner pot and is made of a material with high thermal conductivity, and the pot lid is made of a material with low thermal conductivity. An outer lid covered with a material,
A pot lid temperature detection sensor provided on the outer lid at a position in close contact with the pot lid, a shoulder heat retention heater provided on the shoulder of the inner pot, and rice cooking process control of the shoulder heat retention heater and the rice cooking heater. It has a control means for performing the following based on the output of the pot lid temperature detection sensor, and the control means includes a rice cooking capacity determining means for detecting the temperature of the pot lid temperature detection sensor and determining the rice cooking capacity. A heating jar for cooking rice. 2. An inner pot, a rice cooking heater provided at the bottom of the inner pot, a pot lid made of a material with high thermal conductivity that covers the inner pot, and an outer lid that covers the pot lid with a material with low thermal conductivity. ,
A pot lid temperature detection sensor provided on the outer lid at a position in close contact with the pot lid, a shoulder heat retention heater provided on the shoulder of the inner pot, and rice cooking process control and heat retention control of each of the heaters. It has a control means based on the output of the lid temperature detection sensor, and the control means starts energizing the shoulder heat retention heater when the rice cooking process control ends and the temperature becomes below a predetermined temperature. A rice-cooking heat-retaining jar characterized by comprising a means for controlling heat retention by heating a pot lid by heat conduction. 3. The rice cooking device according to claim 1 or 2, wherein the pot lid temperature detection sensor is fixed inside a sensor case having elasticity that protrudes downward from the inner surface member of the outer lid and comes into close contact with the pot lid. Insulation jar. 4. The pot lid is made of a material with high thermal conductivity, and has a shape that touches the inner pot at the shoulder and covers the inner pot, and further includes:
Corresponding to the position of the sensor case that protrudes downward,
The rice cooking/warming jar according to claim 3, further comprising an annular rib having a flat upper surface.