JPS59131313A - Controller of rice cooker - Google Patents

Abstract

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

Description

[Detailed description of the invention] The present invention relates to a rice cooker control device.

In general, an automatic rice cooker controlled by a microcomputer has a mode in which a predetermined heating pattern, that is, preheating, high heating, medium heating, maintaining boiling, uneven heating, and keeping warm is performed by program control.

Conventionally, when cooking rice using this program control, if there was a power outage or the power plug was accidentally pulled out while keeping the rice warm, in order to continue keeping the rice warm after the power was restored or the power plug was plugged in, the switch had to be turned on again. This has the disadvantage that the operation is complicated, as it requires re-insertion.

The present invention has been made in view of the above-mentioned drawbacks, and its purpose is to provide a rice cooker that simplifies operation by automatically continuing to keep warm when the power supply is restarted when the power supply is stopped during keeping warm. The purpose of the present invention is to provide a control device for the following.

An embodiment of the present invention will be described below.

FIG. 1 schematically shows the configuration of the present invention.

1 is a rice cooking heater provided to heat the bottom surface of the inner pot 2 of the rice cooker A via a heat transfer member 3; 4 is a heat-retaining heater;
This heat-retaining heater 4 is provided so as to heat the upper side surface of the inner pot 2 via the outer container 5. Reference numeral 6 denotes temperature detection means including a thermistor 6-1 as an example of a temperature measuring element, and the thermistor 6-1 is provided so as to be in contact with the bottom surface of the inner pot 2. Reference numeral 7 denotes a rice cooking mode setting means which stores a rice cooking mode program using temperature and time as parameters, and is usually constituted by a ROM. 8 is a rice cooking mode control means which inputs the temperature signal from the temperature detection means 6 and the time signal from the time measurement means 9, and controls the rice cooking heater 1 and the warming heater 4 according to the rice cooking mode program set in the rice cooking mode setting means 7. It outputs a signal that controls the on/off operation of the rice cooker heater 1 and the amount of electricity supplied to the rice cooking heater 1. Reference numeral 10 denotes heater energization amount control means, which inputs a signal from the rice cooking mode control means 8 and determines the amount of energization to the rice cooking heater 1 . 11 is a switch means;
A signal from the rice cooking mode control means 8 is inputted to control the on/off operation of energizing the rice cooking heater 1 and the warming heater 4.

In the present invention, if a temperature signal higher than a certain temperature is sent from the temperature detection means 6 to the rice cooking mode control means 8 before reaching a predetermined rice cooking mode or within a certain period of time, the rice cooking mode control means 8 sends a signal to the switch means 11. is sent out, the power supply to the rice cooking heater 1 is turned off, and the power supply to the warming heater 4 is controlled to be turned on.

In addition, in a preferred embodiment of the present invention, as shown in FIG. 1, a thermistor 12-1 for detecting the side temperature of the inner pot 2, a temperature detecting means 12 including this thermistor 12-1, and a rice cooking power determining device are further provided. means 13 are provided.

The rice cooking power determining means 13 determines the amount of content in the inner pot 2 by measuring the rate of temperature rise over a certain period of time from the temperature detecting means ν, and controls the heater energization amount control means 10 to determine the amount of heater energization according to the capacity. send a signal to. Further, the heater energization amount control means 10 inputs a signal from the temperature detection means 12 at the start of rice cooking, and performs control such that if the starting temperature is high, the amount of heater energization is decreased, and conversely, if the starting temperature is low, the amount of heater energization is increased. We will also do Furthermore, in the initial state (when the power is turned on), the rice cooking mode control means 8 inputs a signal from the temperature detection means 12, and if the inner pot temperature is 55° C. or higher, the rice cooking mode control means 8 turns off the electricity to the warming heater 4. It is also possible to perform control such as shifting to a heat retention mode.

FIG. 2 shows a schematic sectional view of one embodiment.

Reference numeral 20 denotes a control unit installed on the outer body of the rice cooker, and a microcomputer 21 as a control circuit for realizing each means shown in FIG. 1 is built inside the control unit. 22-2
Reference numeral 4 indicates various switches for operating this microcomputer 21. The thermistors 6-1 and 12-1 are brought into contact with the bottom and side surfaces of the borehole steel 2, respectively, by the pressing force of the spring, and the detection signals of both thermistors 6-1 and 12-1 are input to the microcomputer 21. The wires are connected so that the 25 is a power supply circuit, and microcomputer 2
In response to the control signal from 1, the rice cooking heater 1 and the warming heater 4 are energized. The rice cooking heater 1 is embedded in a heat transfer member 3 that contacts the bottom surface of the inner pot so that the heat generated therein is effectively transmitted to the bottom surface of the inner pot. The heat retaining heater 4 is provided surrounding the upper side surface of the outer container 5 so as to be transmitted to the inner pot 2 via the outer container 5. 26 is the lid of the inner pot. Although not shown in the figure, a heat insulating material is filled around the outer container 5 for heat retention, and the lid 26 can also be provided with a known pressure regulating device. 19 is a micro switch,
The presence or absence of the inner pot 2 is detected, and if the inner pot 2 is present, it is turned on and a power supply circuit 25 is turned on, and until the inner pot 2 is placed, the power supply circuit 5 is turned off to prevent empty cooking.

In this embodiment, an electric circuit system directly related to the operation of the rice cooking heater is shown in FIG. Thermistor 6 on the bottom side of the inner pot
-1 and the thermistor 2-1 on the side are respectively provided between the power supply DD and the ground via resistors U and R2, and each detection signal is sent to N converters of the microcomputer 21. Also input ports.

It is input to K1 and converted into a digital signal.

The switch 22 is a rice cooking switch for operating the rice cooking operation, and the switch 23 is a switch for setting the timer since this embodiment has a timer function as described later. Signals from the respective switches 22 and 23 are also input to the microcomputer 21.

The microcomputer 21 controls the gate signal of the triac 28 via the driver 27 by sending an on/off signal to the driver 27. The rice cooking heater is connected to the AC power supply 2 via its triac 28.
On/off control is performed by connecting to 9.

In this embodiment, the amount of electricity supplied to the rice cooking heater 1 is controlled by the duty ratio of the on-time controlled via the triac 28. That is, when the microcomputer 21 inputs the temperature signals from the thermistors 6-1 and 12-1, the microcomputer 21 inputs the temperature signals from the thermistors 6-1 and 12-1, and then the microcomputer 21 inputs the temperature signals from the thermistors 6-1 and 12-1.
5 seconds) to output an on signal for an appropriate time and dry no <-
27 turns on the triac 28. Since the rice cooking heater 1 is energized and heated only during the time when the triac Z is on, the desired amount of energization (rice cooking power) can be achieved by changing the energized time.

FIG. 4 shows the flowchart of the control unit 20 in this embodiment.

The switches that can be operated by the operator include a rice cooking switch 22 for starting and stopping the rice cooking operation, a timer switch 23 for setting the time until the start of the rice cooking operation, and a browning switch 24 for adjusting the degree of burning according to preference.
There are three. Reference numeral 30 denotes a display panel that displays the progress of the engraving operation as it progresses according to the program.
Numbers 1 to 38 are provided, and they are sequentially lit one by one as the program progresses. 40 and 41 are time display panels that display the remaining time until the rice cooking operation starts when the timer is set by the timer switch 23;
0 is a single digit 7 segment LED element that represents time, 41
represents the minutes using a surface emitting device with the number 30 displayed on it.

Next, the operation of one embodiment will be explained.

FIG. 5 shows the relationship between the rice cooking mode program executed in one embodiment and the bottom temperature of the inner pot.

At the beginning of the rice cooking operation, the rice is cooked at a low temperature for sufficient moisture absorption, for example, for 6 minutes. This stage is called preheating mode.・Next, increase the power of the rice cooking heater to the maximum. This stage is called middle Patsupa mode. And the inner pot side temperature is 50
When the temperature exceeds ℃, the content amount is judged and the power supply is controlled according to the capacity. This stage is called power control mode. In this mode it will eventually boil over. After starting the power control mode, increase the rice cooking heater power to 30% for a certain period of time.
% to maintain a boiling state. This stage is called boiling maintenance mode. As the water continues to boil, the water will eventually disappear and the temperature will begin to rise. When the temperature reaches 137°C, it enters uneven mode.

In the uneven mode, after the rice cooking heater 1 is turned off for a certain period of time, the rice cooking heater 1 is turned on for a time corresponding to the set value of the burn switch 24, and then turned off again to complete the rice cooking operation and enter the warming mode. In the heat retention mode, the temperature of the rice is controlled to be 70° C. by turning on and off the heat retention heater 4.

The above is a normal rice cooking operation, but for example, if the temperature at the bottom of the inner pot has already exceeded 137°C in power control mode, it will be determined that the inner pot is empty and the subsequent steps of the program will be omitted. to switch to keep warm mode. In addition, if the thermistor installed on the side of the inner pot is not normal, rice cannot be cooked according to the program, so normal rice cooking mode with constant rice heater power is executed, but in that case - normal rice cooking mode starts. After that, if the temperature at the bottom of the inner pot reaches 137℃ or higher within a certain period of time, it will assume that the inner pot is empty and will switch to keep warm mode.)
I have to.

The above operation will be explained in more detail according to the flowchart.

FIG. 6 represents the initial state. When you turn on the power, first
An abnormality in the thermistor 6-1 (hereinafter referred to as the first thermistor) on the bottom of the inner pot is detected (step S□).

Abnormality detection is performed as follows. If the thermistor is disconnected, it will have a high resistance and will be in the same state as at low temperatures, and if it is shorted, it will have low resistance and will be in the same state as at high temperatures. Here, in the initial state, the first thermistor 6-1
A high resistance value corresponding to a resistance value of -20℃ or less, or 1
If the resistance value is low corresponding to 50° C. or higher, it is determined that the first thermistor 6-1 is abnormal, and the abnormality is notified. Next, the temperature is detected by the thermistor 12 on the side of the inner pot (referred to as the second thermistor on U) (step b
2).

If the side of the inner pot is over 55℃, it will switch to keep warm mode and
If the temperature is below 5°C, the timer switch 23 and rice cooking switch 22 are read. If the timer switch 23 is on, the mode shifts to the timer set mode (step S3), and if the timer set switch 23 is off and the rice cooking switch 22 is on, the mode shifts to the preheating mode (step s4).

FIG. 7 shows an operation flowchart of the heat retention mode. The insulating heater 4 is controlled so that the rice temperature becomes 70°C (step S'h). When the rice cooking switch 2 is pressed during the heat retention mode, the rice cooker enters a stopped state (step S6).

Also, an abnormality in the second thermistor 12-1 is detected during the heat retention mode (step S7). Second thermistor 12-1
The abnormality detection is also the same as in the case of the first thermistor 6-1, or in this case, it is determined that it is abnormal if it becomes a high resistance value corresponding to 20°C or lower or a low resistance value corresponding to 130°C or higher.

A flowchart of the timer setting operation is shown in FIG.

When the timer switch 23 is pressed, the set time will be displayed (Slap S), and each time the timer switch 23 is pressed, the time will be displayed or increased in 30 minute increments (increment).
(Step S12゜S). Then, when the rice cooking switch 22 is pressed (step S), the timer operation is started.

A flowchart of the timer operation is shown in FIG.

The elapsed time is subtracted from the displayed set time, the remaining time is displayed (step S), and when the remaining time reaches 0, the mode shifts to preheating mode (step 516). When the rice cooking switch n is pressed during this timer mode (step S), the timer setting is canceled and the process returns to the initial state.

Next, the rice cooking operation will be explained with reference to FIGS. 10 to 14.

In the preheating mode (Fig. 10), first, the second thermistor 1
Measure the inner pot temperature according to 2-1, 20℃ or less, 20-3
Depending on whether the temperature is 3° C. or 33° C. or higher, the rice cooking heater 1 is energized and heated with appropriate electric power (steps S20 and S2□). After preheating for a certain period of time (for example, 6 minutes), the electric power of the rice cooking heater 1 is increased to the maximum, and the mode is shifted to the next medium rice cooking mode (step S23).
, 524).

If the rice cooking switch 22 is pressed in this preheating mode, if the timer switch n is not on when the rice cooking switch 22 is released and turned off, the rice cooking operation is canceled and returns to the initial state (step S -+S,S
). This operation starts when cooking rice 22 40
This is done when 41 is desired to be canceled for some reason. If the timer switch 23 is pressed when the pressed rice cooking switch 22 is released, the mode shifts to the normal rice cooking mode (steps S22→S4o, 541). This operation is performed in an inspection process before shipment at a factory.

In the medium heat mode (Fig. 11), the second thermistor 12
If the detected temperature of -1 is the highest of 37 degrees Celsius, it will continue to operate moderately, but if the second thermistor 12-1 is 37 degrees Celsius at point B.
If the temperature is detected to be .degree. C. or higher, there is a possibility that the second thermistor 12-1 is abnormal or the rice is being cooked dry, so the mode shifts to the normal rice cooking mode (step 525).

Under normal conditions, after the start of the middle pup movement, a certain period of time (for example, 10
minutes), the second thermistor 12-1 detects 50°C (step S26.S2□). However, if the second thermistor 12-1 does not detect 50°C even after a certain period of time has passed, the second thermistor 12-1 detects 50°C within 12-1 It is determined that there is some other abnormality and the process shifts to normal rice cooking mode (step 526).

When the second thermistor 12-1 detects 50° C. in step S27, the second thermistor 12-1 detects the temperature again after a certain period of time (for example, 90 minutes) from that point (steps S28, 529). Then, the content amount is determined based on the rate of temperature rise over a certain period of time, and the amount of electricity supplied to the rice cooking heater 1 is controlled to be electric power corresponding to the content amount, and the process moves to the next power control mode (step S3
Otsu.

In the power control mode (Fig. 12), electricity is applied and heated for a certain period of time (for example, 4 minutes) with a controlled amount of electricity (
Step 532). Normally, the water boils at this stage, but since water remains, the temperature detected by the first thermistor 6-1 never exceeds the boiling point of water.

If the first thermistor 6-1 detects 137°C or higher in this power control mode, it is determined that the inner pot is empty, and the mode shifts to the keep warm mode (step 531). After a certain period of time has elapsed in step S32. After that, shift to boiling maintenance mode and reduce the power to 70% of the above control power value (
Step 533). Eventually, when boiling is completed and the water disappears, the temperature of the rice will rise, so the first thermistor 6-1 will change to 1.
If it detects a temperature of 37℃ or higher, it will move to the next uneven mode (
534). If an abnormality occurs in the first thermistor 6-1 and 137°C is not detected, the system shifts to the uneven mode after a certain period of time (for example, 25 minutes) has elapsed after starting the boiling maintenance mode (step 535). ).

Next, the operation when the power supply is stopped due to a power outage or the like during the heat retention mode will be explained with reference to FIG.

If, for example, a power outage occurs during heat retention and the power is cut off, the heat retention operation will stop. After that, when the power is restored, thermistor 1 at that time
If the temperature of the inner pot detected in step 2-1 is above the predetermined value, the temperature keeping operation starts (step S2λ).If the temperature of the inner pot after the power is restored is below the predetermined value, the process waits for a command (steps 53 to 2-1). 4).

As explained above, in the present invention, when the power supply stops due to a power outage or when the power plug is accidentally pulled out while keeping warm, the power is restored or when the power supply is inserted when the power plug is inserted. If the inner pot temperature is equal to or higher than a predetermined value when the heating is resumed, the heating operation is automatically continued, which simplifies the operation.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram explaining the present invention in detail, Fig. 2 is a schematic sectional view showing one embodiment of the invention, Fig. 3 is a main circuit diagram of one embodiment, and Fig. 4 is an embodiment. FIG. 5 is a diagram showing a panel of the control unit used, FIG. 5 is a diagram showing a rice cooking program in one embodiment, and FIGS. 6 to 12 are flowcharts showing the operation of one embodiment. 1... Rice cooking heater, 2... Inner pot, 4... Heat retention heater, 6.12... Temperature detection means, 6-1.12-1.
...Thermistor, stage, △ timing means, 10° - evening energization amount control means, 11°. Switch means, 21...Microcomputer Fig. 5, Figure 6, Fig. 8, Fig. 9, Fig. 10, Fig. 11, Fig. 12

Claims (1)

[Claims] (1) In a control device for a rice cooker that heats and cooks rice according to a predetermined program, the control device includes a temperature detection means for detecting the temperature of the inner pot of the rice cooker, and a heating operation according to the program. The above-mentioned temperature detection means when the power is turned off and then turned on again while the heat-keeping operation is being performed: If the temperature of the inner pot detected by this is equal to or higher than a predetermined value, the heat-keeping operation is automatically performed. A control device for a rice cooker, characterized by comprising means.