JPH0137925B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electric jar rice cooker that is used in general households and has the function of keeping warm and cooking rice, particularly an appliance that incorporates a timer that allows the rice cooking start time to be set. It is related to the circuit configuration.

Conventional configuration and its problems In recent years, electric jar rice cookers used in general households that have heat retention and rice cooking functions use microcomputers to adjust the heating power, etc. in the rice cooking process according to a fixed program. However, it is suggested that you cook the rice.

Hereinafter, the conventional microcomputer-equipped jar rice cooker mentioned above will be described with reference to the drawings.

FIG. 1 shows an electrical circuit diagram.

In FIG. 1, 1 is a power plug, 2 is a power switch, 3 is a temperature fuse to prevent excessive temperature rise, and 4 is a capacitor for noise reduction. 5 is a lower heater provided at the bottom of the main body; 6 is a power control means such as a triax for energizing the lower heater 5; 7, 8
indicate the lid heater and side heater, respectively. Reference numeral 9 denotes a power control means such as a trial actuator when the lower heater 5, lid heater 7, and side heater 8 perform a heat-retaining operation.

10 is a resistor, 11 is a rectifier, and 12 is a capacitor, which constitutes a power source for the control circuit.

13 is a Zener diode, which makes it possible to obtain a stabilized power source. 14 is a microcomputer, 15 is a temperature input section consisting of a heat-sensitive table attached to the side of the pot, and 16 is an output display section. Reference numerals 17 and 18 indicate transistors, which are used to ignite the triacs 6 and 9, respectively, which are power control means.

The transistor 19 is driven by a thermoswitch 20 for detecting the completion of rice cooking, which is placed in contact with the bottom of the pot, and inputs to the microcomputer 14 whether or not it is in the rice cooking mode based on its level.

The operation of the jar rice cooker configured as above will be explained below. When cooking rice, first plug the power plug 1 into the power source, turn on the power switch 2, and then turn on the thermo switch 20. Then, the transistor 19 becomes conductive, and the microcomputer 14 is informed that it is in the rice cooking operation mode. Then, an output from the microcomputer 14 is generated, the power control means 6 is ignited, the lower heater 5 is energized, and the rice cooking operation is started according to a fixed rice cooking program.

At the beginning of rice cooking, while detecting the temperature of the pot using the temperature input section 15, the lower heater 5 is energized to keep the pot temperature constant, and a submergence operation is performed for a certain period of time. Thereafter, the lower heater 5 is fully energized, and when the temperature inside the pot exceeds a certain temperature, the amount of rice to be cooked is determined and the heat power is adjusted. When the rice cooking is finished, thermo switch 2
0 is activated, the transistor 19 is turned off, and the microcomputer 14 enters the heat preservation mode. In this case, the power control means 9 is ignited, the lower heater 5, the lid heater 7, and the side heater 8 are energized to perform a heat-retaining operation.

However, in the circuit configuration as described above, the control circuit and the heater circuit are connected in a complicated manner, and therefore, when a motor timer is provided, there is a drawback that the connection cannot be easily made. This is because a timer is installed in the power supply path, for example, when power switch 2
If this is used as a timer contact, the timer will turn on the power after the set time has elapsed, but in that case, regardless of whether the rice cooking switch is turned on or not, the power will turn on after the set time has elapsed. is injected. Therefore, if the user forgets to turn on the rice cooking switch and sets the timer, the rice will simply keep warm after the timer set time has elapsed, causing the problem that the rice will not cook. be.

FIG. 2 shows an example in which a timer is added to a general jar rice cooker that does not use a microcomputer.

In Fig. 2, 30 is a power plug, 31 is a power switch, 32 is a temperature fuse, 33 is a capacitor for noise reduction, 34 is a lower heater provided at the bottom of the main body, 35 is a timer device, and 36 is a timer operation display. 37 is a thermoswitch for detecting the completion of rice cooking, 38 is a lid heater, 39 is a side heater, 40 is a power control means such as a triac, and 41 is a temperature detection device.

To explain the operation when a timer is added to the general jar rice cooker that does not use a microcomputer as shown in FIG. 2, the timer 35 is connected in series with a thermoswitch 37 for detecting the completion of rice cooking and a lower heater 34. Therefore, the time switch operates only when the thermo switch 37 for detecting the completion of rice cooking is turned on, and the neon tube 36 for displaying when the switch is operating also lights up.
Therefore, in this case, the above-mentioned problems will not occur during use.

Next, returning to FIG. 1 and considering the case where a time switch is provided between the lower heater 5 and the power control means 6, the power control means 6 is intermittently driven by the microcomputer 14. Therefore, the operating time of the motor timer is not constant, and by the time the actual rice cooking starts, the series of programs in the microcomputer have already completed, and automatic determination of the amount of rice to be cooked is no longer possible. This will cause problems.

Purpose of the Invention In view of the above drawbacks, the present invention aims to provide a specific circuit configuration for adding a motor timer to a rice cooker equipped with a microcomputer.

Structure of the Invention In order to achieve the above object, the jar rice cooker with a timer of the present invention includes a main body, a lid provided on the top surface of the main body so as to be openable and closable, and a pot detachably housed in the main body. , a lower heater provided on the inner bottom of the main body, a side heater provided on the inner surface of the main body, a lid heater provided on the lower surface of the lid, a microcomputer that stores the rice cooking process, and the heater. and a motor timer, the C contact of the motor timer is connected to one end of the power supply, the A contact of the motor timer is connected to the coil of the motor timer, and the B contact of the motor timer is connected to the coil of the motor timer. The present invention is characterized in that the coil of the motor timer and the rice cooking operation input terminal of the microcomputer are switched by a thermoswitch connected to a heater or power control means and used to detect the completion of rice cooking.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 3 shows an electric circuit diagram of a jar rice cooker with a timer according to an embodiment of the present invention. In Fig. 3, 50 is a power plug;
51 is a power switch, 52 is a temperature fuse, 52
53 is a contact point switched by a timer, 54 is a lower heater, 55 is a power control means, 56 and 57 are a lid heater and a side heater, and 58 is a power control means for heat retention control. 5
9 is a motor timer for switching the contact 53; 60 and 61 are neon tubes for displaying the timer set and fixed resistors. 62 is a thermo switch for detecting the completion of rice cooking. The transistor 63 is operated by a thermoswitch 62, and inputs the operation mode to the microcomputer 64, either cooking rice or keeping warm. 65 is an input section for inputting temperature, etc., consisting of a heat-sensitive element, etc. provided in contact with the side of the pot;
Reference numeral 6 indicates an output section for display, etc.

A transistor 67 amplifies the output of the microcomputer 64 and turns on the power control means 55. A transistor 68 is likewise provided for firing the power control means 58.

A resistor 69 and a rectifier 70 charge a capacitor 71 and constitute a power source for the control circuit.

Further, stabilized power is supplied to the microcomputer by 72 Zener diodes.

The operation of the above configuration will be explained below.

First, when the timer is at the zero time point, the timer contacts connect 53c and 56b, and power is supplied from one end of the lower heater 54 to each heater, control circuit, etc. Therefore now,
When the power switch 51 is turned on and the thermoswitch 62 for rice cooking completion detection is turned on, the thermoswitch contacts 62c and 62a are connected.
The base current of the transistor 63 disappears, the transistor 63 becomes non-conductive and has a high resistance, and the microcomputer 64 starts the rice cooking operation. The output of the microcomputer 64 turns on the transistor 67, thereby making the power control means 55 conductive and energizing the lower heater 54. During this time, a heating process using small electric power for submersion, automatic determination of rice cooking amount, etc. are performed based on a signal from the temperature input section 65, and the power control means 55 performs on/off control. When the rice has finished cooking, thermo switch 6
No. 2 switches to the side where 62c and 62b are connected, goes through the additional cooking process and the uneven cooking process, and then moves to the warming operation.

Next, when the timer is set, the contacts of the timer are connected so that 53c and 53a are connected. At this time, the thermo switch 6 for detecting the completion of rice cooking
2 is on the heat retention operation side where 62c and 62b are connected, the coil of the motor timer 59 is not energized, so the motor timer 59 does not operate and the timer set indicator lamp 60 does not light up. When the thermo switch 62 is turned on and the contacts 62c and 62a are connected, power is connected to both ends of the coil of the motor timer 59, and the motor timer 59 operates and the motor timer set indicator lamp 60 also lights up. Light. Further, since the contact 53 is open, no power is supplied to the control circuit, and the process of the microcomputer 14 does not proceed.

As described above, according to this embodiment, by associating the rice cooking switch with the timer contact, the motor timer operates and displays only when the rice cooking switch is set to the rice cooking side, and the user can On the other hand, it does not cause any problems.

Effects of the Invention By configuring the rice cooker as described above, by limiting the operation of the timer and the setting display of the timer to when the rice cooking switch is turned on, the rice cooking operation can be reliably performed after the timer setting time has elapsed. Since the rice cooking is controlled by a microcomputer, it is possible to cook fluffy and delicious rice.

[Brief explanation of drawings]

Figure 1 is an electric circuit diagram of a conventional jar rice cooker using a microcomputer, Figure 2 is an electric circuit diagram of a conventional jar rice cooker with a timer, and Figure 3 is an electric circuit diagram of a conventional jar rice cooker with a timer according to an embodiment of the present invention. 1 is an electrical circuit diagram of a jiya rice cooker equipped with a microcomputer.

Claims (1)

[Claims] 1 a main body, a lid provided on the top surface of the main body so as to be openable and closable, and a pot removably housed in the main body;
A lower heater provided on the inner bottom of the main body, a side portion provided on the inner surface of the main body, a lid heater provided on the lower surface of the lid, a microcomputer that stores the rice cooking process, and controls the heater. power control means and a motor timer, the C contact of the motor timer is connected to one end of the power supply, the A contact of the motor timer is connected to the coil of the motor timer, and the B contact of the motor timer is connected to the heater or the motor timer. A jar rice cooker with a timer, which is connected to a power control means and configured to switch between the coil of the motor timer and the rice cooking operation input terminal of a microcomputer by a thermoswitch for detecting rice cooking completion.