JPS6360656B2 - - 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 explained with reference to the drawings.

FIG. 1 shows an electrical circuit diagram of this conventional microcomputer-equipped jar rice cooker.

In FIG. 1, 1 is a power plug, 2 is a power switch, 3 is a temperature fuse, 4 is a capacitor for noise reduction, 5 is a lid heater, 6 is a lower heater, and 7 is a side heater. In addition, 8 is a relay contact for controlling the power of the lower heater, 9 is a rice cooking switch operated by a heat-sensitive device placed in contact with the bottom of the pot to detect the start and completion of rice cooking, and 10 is a series connection of each heater when keeping warm. It is a power semiconductor consisting of a circuit and a triax for controlling the power of the side heaters during rice cooking.

11 is a microcomputer that stores a rice cooking program, 12 is a Zener diode that creates a constant voltage power supply for the microcomputer, 13 is a relay coil that operates relay contact 8, 14 is an output section for displaying operation, etc., and 15 is connected to the pot. This is a temperature input section from a heat-sensitive element, etc. 16, 17, 18 are transistors, 19, 20, 21 are diodes, 2
2 and 24 are resistors, and 23 and 25 are capacitors, respectively.

The operation of the jar rice cooker configured as above will be explained below. First, when cooking rice, plug the power plug 1 into the power source, turn on the power switch 2, and then turn on the rice cooking switch 9. At this time, contacts 9a and 9c are connected.

Further, the electrolytic capacitor 23 is charged through the diode 19 and the resistor 22. This power supply energizes the drive control section including the microcomputer 11 and starts operation. The output of microcomputer 11 is amplified by transistor 16 and ignites power semiconductor 10 . Similarly, the relay coil 13 is driven by the transistor 17, the relay contact 8 is moved from 8a to 8b, and the lower heater 6 is energized.

In the initial stage of rice cooking, the temperature input unit 15 detects the pot temperature, and the lower heater 6 and the side heater 7 are energized to keep the pot temperature constant, resulting in a submergence process. After a certain period of time has elapsed, the lower heater 6 and side heater 7 are fully energized. During this time, the amount of rice cooked is detected by detecting how the pot temperature rises. When the pot temperature exceeds a predetermined temperature, the lower heater 6 and the side heater 7 are turned on. The power supply to the side heater 7 is controlled to adjust the heating power. Thereafter, the heat-sensitive device placed at the bottom of the pot detects the completion of rice cooking and the energization control is continued until the switch 9 is switched from the 9a side to the 9b side.

Next, a description will be given of the heat retention operation when the switch 9 is switched from the 9a side to the 9b side. When the switch 9 is turned on to the 9b side, the base current of the transistor 18 flows through the resistor 24 and the diode 20 at a half-wave of the power supply. The base circuit has a half wave smoothed by a capacitor 25, and the collector output of the transistor 18 becomes a DC signal, which is input to the microcomputer 11 to perform a heat-retaining operation. In this case, the power semiconductor 10 is turned on and off according to the pot temperature from the temperature input section 15, and the series circuit of the lid heater 5, the lower heater 6, and the side heater 7 is energized to perform a temperature control operation for keeping warm. It's summery. Note that each operation mode is performed by causing an LED or the like to emit light on the display section 14.

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 switch 2
If this is used as a timer contact, the power will be turned on after the time set by the timer has elapsed, but in that case, regardless of whether the rice cooker switch 9 is turned on or not, the timer set time will elapse. Then the power is turned on. Therefore, if the user forgets to turn on the rice cooking switch and sets the timer, the rice will simply keep warm after the set time on the timer has elapsed, causing the problem that the rice will not cook. That's what I do.

Furthermore, in the configuration shown in FIG. 1, the switch 9 is used to switch between the rice cooking operation and the warming operation. At this time, the transistor 18 is connected to the contacts 9b-9c.
However, since the 9a side was switching a large current, there was a possibility that the contacts would wear out or become contaminated, resulting in poor contact.

Purpose of the Invention In view of the drawbacks of the conventional example, the present invention provides a specific circuit configuration in which a motor timer is added to a jar rice cooker equipped with a drive control circuit having a microcomputer, and an input signal for rice cooking operation is transferred to a jar rice cooker equipped with a drive control circuit having a microcomputer. The purpose of this document is to provide a concrete configuration for inputting data into the system.

Configuration of the Invention In order to achieve the above object, the present invention is characterized in that a jar rice cooker with a timer is configured as follows.

That is, a main body, a lid provided on the top surface of the main body so as to be openable and closable, a pot removably housed within the main body, a lower heater provided on the inner bottom of the main body, and a side heater provided on the inner surface of the main body. A power semiconductor, a side heater, and a lower heater are connected to a common contact of the switch, and the lid heater is connected in series to a normally closed contact of the switch, and connected to a power source. The normally open contact of the first switch is also connected to the power supply of the power semiconductor.

The connection points of the side heater and the bottom heater are connected to one contact of the timer via the power control means. Further, one end of a coil of a timer motor is connected to a connection point between the side heater and the lower heater, and the other end of the coil is connected to a power source through another contact of the timer and a common contact.

Furthermore, the circuit was configured so that the input signal for the drive control section, which consisted of a microcomputer, a pan temperature detection device, etc., was taken from the common contact of the switch.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 shows an electric circuit diagram of a jar rice cooker with a timer according to an embodiment of the present invention. 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 lid heater provided on the bottom surface of the lid, 35
36 is a lower heater provided at the inner bottom of the main body, and 36 is a side heater. Further, 37 is a timer motor coil, 38 is an electric contact of the timer, 39 is a switch for inputting the start and completion of rice cooking, which is composed of a micro switch that is automatically switched by a heat sensitive part, 40 is a relay coil, and 41 is a A switch that is turned on and off by a drive control section; 42 is a power semiconductor consisting of a triax for controlling the power of the heater; 43 is a microcomputer; 4
4 is an output display section, 45 is a temperature input section for the pot consisting of a heat-sensitive element in contact with the pot, 46, 47, 48 are transistors, 49, 50, 51 are diodes, 52
53, 54, 55 are capacitors, 56, 57 are resistors, and 58 is a neon lamp.

The operation of the circuit configuration of the jar rice cooker with a timer configured as described above will be explained below.

First, when the timer is at the time limit 0 point, the timer contacts 38C and 38A are connected,
When the rice cooking switch 39 is turned on to set the rice cooking mode and the contacts 39b and 39c are connected, the current of the drive control circuit including the microcomputer flows through the resistor 56, the diode 48, the capacitor 53, and the resistor 5.
7. It is made up of a Zener diode 52 and a capacitor 54, and the relay contact 41 and the power semiconductor 42 are driven according to the rice cooking program, and the lower heater 35 and side heater 36 are energized to start rice cooking.

After this, a heating process with small power for flooding,
The microcomputer 43 automatically determines the amount of rice to be cooked, etc. based on the signal from the temperature input section 45, and the power control means controls on/off of the heater.

When rice cooking is finished, the rice cooking switch 39 is turned to 39a.
Switch to -39c side. As a result, although the transistor 48 had been off until then, a half wave of the power flows to the base through the diode 50 and the heater 34, and the transistor 48 is turned on. A time constant capacitor 55 is inserted into the base circuit of the transistor 48, and the output of the transistor 48 is a DC level signal, which is input to the microcomputer 43 to indicate that the operating mode has been switched. After this, the heating operation is started through the additional cooking process and the uneven cooking process.

Next, when the timer is set, the timer contacts 38C and 38B are connected. At this time, if the rice cooking switch 39 is connected to 39a to 39c and is in the warming operation side, the timer motor is not energized, and the 58 connected to both ends of the motor coil is not energized.
The neon lamp also does not light up.

On the other hand, turn on the rice cooking switch 39 and
When c and 39b are connected, the timer motor is connected to the power source via the lower heater 35, the timer is activated, and the timer set indicator lamp 5 is turned on.
8 is also lit. Furthermore, since the contacts 41 and 38A are open, power is not supplied to the control circuit, and the problem that only the microcomputer operates and the rice cooking process progresses without permission occurs.

Effects of the Invention As described above, by connecting the contacts of the timer as in the present invention, the operation of the timer and the setting display of the timer are limited to when the rice cooking switch is turned on. In addition, since the rice cooking is controlled by a microcomputer, fluffy and delicious rice can be cooked.

Furthermore, it is equipped with a timer, which improves usability.

In addition, since the control circuit takes the input signal of the operation mode from the part through which the current flows, the contacts are cleaned, and even though the base current of the transistor is used as input, it is possible to achieve high reliability with few occurrences of contact failures.

[Brief explanation of drawings]

FIG. 1 shows an electric circuit diagram of a conventional jar rice cooker, and FIG. 2 shows an electric circuit diagram of a jar rice cooker with a timer according to an embodiment of the present invention.

Claims (1)

[Claims] 1. A main body, a lid that can be opened and closed on the top of the main body,
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 power semiconductor, and the side heater provided on the inner surface of the main body. A switch comprising a common contact connecting the lower heater and the lower heater in series, a normally open contact connected to a power source, and a normally closed contact connecting the lid heater to the power source; The connection point between the heater and the lower heater is connected to one contact of the timer through a power control means, and the connection point of both heaters is further connected to the power supply through the coil of the timer motor and the other contact of the timer, A jar rice cooker with a timer configured so that an input signal for a drive control section consisting of a computer, a pot temperature detection device, etc. is obtained from a common contact of the switch.