JPH0426843B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a rice cooker, and particularly to a rice cooker using a microcomputer as a control circuit.

Conventional technology: ROM is used in rice cookers with a built-in microcomputer.
By presetting a predetermined rice cooking program in the read-only memory, the rice cooking operation according to the program can be automatically performed.

However, such automatic rice cookers operate according to a set rice cooking program with time and temperature as factors, so it takes several tens of minutes to inspect the rice cooking operation during the production process. become. Therefore, it is necessary to provide a means for checking the rice cooking operation in a short time.

Purpose In view of the above problems, the present invention aims to provide an automatic rice cooker equipped with a test mode function that allows rice cooking operation to be confirmed in a short time.

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

1 is a rice cooking switch for starting and stopping the rice cooking operation, and 2 is a timer switch for setting the time until the rice cooking operation starts. 3 is a programmed rice cooking operation control means for performing the rice cooking operation according to a preset rice cooking program; 4 is a timer means for operating the programmed rice cooking operation control means 3 after the time set by the timer switch 2 has elapsed;
Reference numeral 5 denotes a normal rice-cooking operation control means that performs the rice-cooking operation with a constant amount of electricity without following the rice-cooking program. 6
is a switch that inputs signals from the rice cooking switch and the timer switch 2, selects the programmed rice cooking operation control means 3, the timer means 4, or the normal rice cooking operation control means 5 based on the combination of these signals, and puts any one of them into the operating state. It is a means of judgment.

The operation of the switch determining means 6 is, for example, when the rice cooking switch 1 is pressed after the timer switch 2 sets the time on the timer means 4, the timer means 4 is operated, and when only the rice cooking switch 1 is pressed, the program rice cooking operation is controlled. operate means 3;
After the start of the programmed rice cooking operation, the rice cooking switch 1 is pressed while the timer switch 2 is kept pressed, and if the rice cooking switch 1 is released first, the operation of the programmed rice cooking operation control means 3 is stopped and the normal rice cooking operation is started. This is to shift to a test mode in which the control means 5 is operated.

In the present invention, the test mode function refers to a function that allows a transition to the normal rice cooking operation control means 5 by operating the rice cooking switch 1 and the timer switch 2, as in the third operation described above.

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

10 is a rice cooking heater provided to heat the bottom surface of the inner pot 12 of the rice cooker 11 via a heat transfer member 13, and 14 is a heat retention heater.

The rice cooking heater 10 is embedded in a heat transfer member 13 that contacts the bottom surface of the inner pot 12 so that the heat generated therein is effectively transferred to the bottom surface of the inner pot 12. Heat retention heater 14
is provided surrounding the upper side surface of the outer container 15 so that heat is transferred to the inner pot 12 via the outer container 15. 16 is a thermistor (hereinafter referred to as a first thermistor) as an example of a temperature measuring element that detects the bottom temperature of the inner pot 12; 17 is a thermistor (hereinafter referred to as a second thermistor) as a temperature measuring element that detects the side temperature of the inner pot 12; (called a thermistor).

The first thermistor 16 and the second thermistor 17 are brought into contact with the bottom and side surfaces of the inner pot 12, respectively, by the pressing force of the spring.
The detection signals of 6 and 17 are sent to the microcomputer 18.
It is wired so that it is input to the Reference numeral 19 denotes a power supply circuit that receives a control signal from the microcomputer 18 and operates the rice cooking heater 10 and the warming heater 14.
energize. 20 is a micro switch, inner pot 1
2 is detected, and if there is an inner pot 12, it is turned on and a power supply circuit 19 is turned on, and until the inner pot 12 is placed, the power supply circuit 19 is turned off to prevent empty cooking. 21 is the lid of the inner pot. Although not shown in the figure, a heat insulating material is filled around the outer container 15 for heat retention, and the lid 21 may be provided with a known pressure regulating device. Reference numeral 22 denotes a control unit containing a microcomputer 18, which is installed on the outer body of the rice cooker 11, and serves as switches for controlling the rice cooker, in addition to the rice cooking switch 1 and timer switch 2 described above, as well as the burner switch 2 described later.
It has 3.

FIG. 3 shows an electric circuit system directly related to the operation of the rice cooking heater 10 in this embodiment. The first thermistor 16 on the bottom side of the inner pot and the second thermistor 1 on the side side
7 are provided between the power supply V _DD and the ground via resistors R ₁ and R _2, respectively, and the respective detection signals are input to A/D converter input ports K ₂ and K ₁ of the microcomputer 18. converted into a digital signal. Rice cooking switch 1 and timer switch 2
The respective signals are also input to the microcomputer 18.

The microcomputer 18 controls the gate signal of the triac 25 via the driver 24 by sending on/off signals to the driver 24. The rice cooking heater 10 is connected to an AC power source 26 via its triax 25, and thereby controlled to be turned on and off.

In this embodiment, the amount of electricity supplied to the rice cooking heater 10 is controlled by the duty ratio of the on-time controlled via the triax 25. That is, when the microcomputer 18 inputs the temperature signals from the first thermistor 16 and the second thermistor 17,
According to the rice cooking mode program that has been set, the driver 24 turns on the triator 25 by outputting an on signal for an appropriate amount of time at regular intervals (for example, 15 seconds) so that the amount of power to the heater is appropriate. Since the rice cooking heater 10 is energized and heated only during the time that the triax 25 is on, the desired amount of energization (rice cooking power) can be achieved by changing the energized time.

FIG. 4 shows a panel of the control unit 22 in this embodiment. The switches that the operator can operate include switch 1, timer switch 2, and burn switch 2 that allows you to adjust the degree of burntness according to your preference.
There are three of them. Reference numeral 30 denotes a display panel that displays the progress of rice cooking as it progresses according to the program, and LEDs (lighting diodes) 31 to 38 are provided for each step. They will be lit one after another.
It is desirable that the LEDs 31 to 38 are appropriately color coded.

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 2;
is a 7-segment LED element with two digits indicating the time,
41 is a surface emitting element on which the number 30 (minutes) is displayed.

motion 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.

The first stage of the rice cooking operation is at a low temperature to allow the rice to absorb enough moisture, for example, for 6 minutes. This stage is called preheating mode. Next, increase the power of the rice cooking heater 10 to the maximum. This stage is called the middle Patsupa mode.
When the temperature detected by the second thermistor 17 exceeds 50° C., the content amount is determined from the temperature gradient, and the supplied power is controlled according to the content amount.
This stage is called power control mode. In this mode it will eventually boil over. After a certain period of time after starting the power control mode, the rice cooking heater power is reduced to a predetermined percentage (for example, 70%) to maintain the 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. If the temperature is a predetermined temperature (e.g.
When the temperature reaches 137°C, the temperature shifts to uneven mode. In uneven mode, the rice cooking heater 10 is turned on for a certain period of time.
After turning off, the rice cooking heater 10 is turned on for a time corresponding to the set value of the burn switch 23, and then turned off again to complete the rice cooking operation and shift to the warming mode. In the heat retention mode, the rice temperature is controlled to be a constant temperature (for example, 70°C) by turning on and off the heat retention heater 14.

The above is a normal rice cooking operation, but for example, in the power control mode, the first thermistor 16
If the detected temperature exceeds the predetermined value (137℃),
It is determined that the inner pot is empty, and the subsequent steps of the program are omitted and the mode is shifted to the keep-warm mode. Also, a second thermistor 1 provided on the side surface of the inner wall
7 is not normal, the rice cooking operation cannot be performed according to the program, so the rice cooking heater 10
In this case, the temperature detected by the first thermistor 16 reaches 137°C within a certain period of time after starting the normal rice cooking mode.
If this happens, it is determined that the inner pot is empty, and the mode is switched to keep-warm mode.

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

FIG. 6 shows the initial state, and when the power is turned on, an abnormality in the first thermistor 16 on the bottom of the inner pot is detected (step S1). Abnormality detection is performed as follows. If the thermistor is disconnected, it will have high resistance and will be in the same state as at low temperatures, and if it is shorted, it will be low in resistance and will be in the same state as at high temperatures. Therefore, in the initial state, the resistance value of the first thermistor 16 is a high resistance value corresponding to −20°C or less, or
If the resistance value is low enough to handle temperatures above 150℃,
It is determined that the first thermistor 16 is abnormal, and the abnormality is notified. Next, the second thermistor 1 on the side of the inner pot
7, the temperature is detected (step S2). If the detected temperature is 55°C or higher, the mode shifts to the warming mode, and if it is lower than 55°C, the timer switch 2 and rice cooking switch 1 are read. timer switch 2
If it is on, the mode shifts to the timer set mode (step S3), and if the timer switch 2 is off and the rice cooking switch 1 is on, the mode shifts to the preheating mode (step S4).

FIG. 7 shows an operational flowchart of the heat retention mode. The insulating heater 14 is controlled so that the rice temperature reaches 70°C (step S5). If rice cooking switch 1 is pressed during the keep warm mode, the rice cooker will stop (step
S6). Also, the second thermistor 17 is
detect an abnormality (step S7). Detection of an abnormality in the second thermistor 17 is the same as in the case of the first thermistor 16, but in this case, an abnormality is determined if the resistance value is high corresponding to 20° C. or lower or low resistance value corresponding to 130° C. or higher.

A flowchart of the timer set operation is shown in FIG. When timer switch 2 is pressed, the set time of 30 minutes is displayed (step S11), and each time timer switch 2 is pressed, the time display is incremented by 30 minutes (step S11).
S12, S13).

Then, when rice cooker switch 1 is pressed (step
S10), 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, and the remaining time is displayed (step S15). When the remaining time reaches 0, the process shifts to preheating mode (step S16). If the rice cooking switch 1 is pressed during this timer mode (step S14), the timer set 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 preheating mode (Figure 10), LED3 in Figure 4
1 lights up. First, the temperature of the inner pot is measured by the second thermistor 17, and the temperature is below 20℃, 20-33℃, or 33℃.
The rice cooking heater 10 is energized and heated with appropriate electric power depending on whether the rice belongs to one of the three types (steps S20 and S21). After preheating for a certain period of time (for example, 6 minutes), the electric power of the rice cooking heater 10 is increased to the maximum, and the process shifts to the next medium heat mode (steps S23 and S24).

If the rice cooking switch 22 is pressed in this preheating mode, if the timer switch 23 is not turned 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 S22→ S40, S41). This operation is performed when you have started cooking rice but want to stop it for some reason. Furthermore, when the pressed rice cooking switch 22 is released, if the timer switch 23 is pressed, the mode shifts to the normal rice cooking mode (steps S22→S40,
S41). This operation is performed in an inspection process before shipment at a factory, and is an operation realized by the present invention.

In the medium patch mode (Fig. 11), the
LED32 lights up further. Second thermistor 17
If the detected temperature of
If a temperature higher than ℃ is detected, the mode shifts to normal rice cooking mode (step S25).

During normal operation, the second thermistor 17 becomes 50 within a certain period of time (for example, 10 minutes) after the start of the medium-speed operation.
Detect the temperature (steps S26, S27).

However, even after a certain period of time has passed, the second thermistor 1
7 does not detect 50℃, the second thermistor 17
It is determined that there is some other abnormality and the process shifts to normal rice cooking mode (step S26).

When the second thermistor 17 detects 50° C. in step S27, the second thermistor 17 detects the temperature again after a certain period of time (for example, 2 minutes) from that point (steps S28 and S29). 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 10 is controlled to be the electric power according to the content, and the process moves to the next power control mode (step S30). ).

In the power control mode (Fig. 12), the fourth
The LED 33 shown in the figure further lights up, and heating is performed for a certain period of time (for example, 4 minutes) at a controlled amount of current (step S32). Under normal conditions, it will boil at this stage, but since there is still water left, the first thermistor 16
The detected temperature will never exceed the boiling point of water. If the first thermistor 16 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
S31).

After a certain period of time has elapsed in step S32, the boiling maintenance mode is entered and the power is reduced to 70% of the control power value (step S33). In the boiling maintenance mode, the LED 34 in FIG. 4 further lights up. When the boiling is completed and the moisture disappears, the temperature of the rice will rise, so if the first thermistor 16 detects a temperature of 137°C or higher, the next mode will be shifted to the uneven mode (step S34).
If an abnormality occurs in the first thermistor and 137° C. is not detected, a transition is made to the uneven mode after a certain period of time (for example, 25 minutes) has elapsed after starting the boiling maintenance mode (step S35).

The normal rice cooking mode will be explained with reference to FIG. In this mode, LEDs 31 to 34 in Figure 4 are lit, and the power applied to the rice cooker heater 1 is set to the maximum power.
It is heated at 70% for a certain period of time (T ₁ ) and shifts to uneven mode (steps S37, S38). In this case, after switching to normal rice cooking mode, a certain period of time (T ₁ )
The detected temperature of the first thermistor 16 is 137℃ before the elapsed time.
When detecting 137℃, if the time until detecting 137℃ is longer than a certain time (T ₂ ), it will shift to uneven mode, but if this time is less than T ₂ , it will change to uneven mode. After making a judgment, the system shifts to the heat retention mode (step S39). Here, the fixed time (T ₂ ) is the time during which the temperature never rises to 137°C unless the inner pot is empty.

Finally, the operation in uneven mode is shown in FIG.

First, the LED 35 in Fig. 4 lights up further and the power to the rice cooking heater 10 is turned off for a certain period of time (steps S50, S51). is determined, and the rice cooking heater 10 is energized and heated for that period (steps S52 to S54). At this point, the LED 36 lights up further. By adjusting the energization time, the degree of burntness can be changed. After a certain period of time, the rice cooking heater 10 is turned off and the LED 37 is further turned on. Eventually the temperature detected by the second thermistor 17 reaches 70°C.
When the temperature drops to
S55). In the heat retention mode, only LED 38 lights up.

Effects As described above, the present invention makes it possible to ignore the rice cooking program and immediately check the rice cooking operation by operating the rice cooking switch and timer switch in a rice cooker equipped with a microcomputer.
The rice cooking operation confirmation process on the production line, which used to take several tens of minutes, can now be performed in just 4 to 5 minutes without the need to install a special switch for test mode, and the test process has been significantly simplified. It started to be shortened.

[Brief explanation of drawings]

Figure 1 is a schematic diagram explaining the configuration of the present invention, Figure 2 is a schematic diagram explaining the configuration of the present invention.
The figure is a schematic sectional view showing one embodiment of the present invention, FIG. 3 is a main circuit diagram of one embodiment, FIG. 4 is a diagram showing a panel of a control unit used in one embodiment, and FIG. 5 is one embodiment. Figures 6 to 14 showing the example rice cooking program are flowcharts showing the operation of one embodiment. 1... Rice cooking switch, 2... Timer switch, 3... Programmed rice cooking operation control means, 4...
Timer means, 5... Normal rice cooking operation control means, 6
...Switch determination means, 18...Microcomputer.

Claims (1)

[Scope of Claims] 1. A rice cooking switch that operates the start and stop of the rice cooking operation, a timer switch that sets the time until the start of the rice cooking operation, and a program rice cooking operation control that causes the rice cooking operation to be performed according to a preset rice cooking program. an automatic rice cooker comprising: a normal rice cooking operation control means for performing the rice cooking operation with a constant amount of electricity; and a timer means for operating the programmed rice cooking operation control means after the time set by the timer switch has elapsed. , switch determining means having an input side connected to the rice cooking switch and the timer switch, and an output side connected to the program rice cooking operation control means, the normal rice cooking operation control means, and the timer means; An automatic rice cooker characterized in that any one of the rice cooking operation control means, the normal rice cooking operation control means, or the timer means is selected and brought into operation.