JPH02271809A - Rice cooker - Google Patents

Abstract

PURPOSE:To execute a timer rice cooking operation and a steaming operation with high accuracy by providing a first time counting means for executing time counting of a holding time for the timer rice cooking operation, and a second time counting means for executing time counting of a continued time for the steaming operation. CONSTITUTION:A series circuit of a bidirectional three-terminal thyristor 17 and a rice cooking heater 6 is connected so as to receive a power source from an attachment plug 18, and a warming heater 7 is connected in parallel to the thyristor 17. Accordingly, when the thyristor 17 is turned off, the rice cooking heater 6 and the warming heater 7 are brought to electric conduction in series, each of them is heated by a small heating capacity and a pot 5 is heated by weak heat, and when the thyristor 17 is turned on, only the rice cooking heater 6 is brought to electric conduction, heated by a large heating capacity and the pot 5 is heated by strong heat. In this case, a voltage adjusting device 19 adjusts a heating value by suppressing an inter-terminal voltage of the rice cooking heater 6. Also, a control circuit device 20 is constituted as a microcomputer containing a storage part 21, a time control part 22 combining a first time counting means for executing time counting of a holding time for a timer rice cooking operation, and a second time counting means for executing time counting a continued time for a steaming operation, and an arithmetic processing part 23.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a rice cooker capable of performing timer rice cooking operation and uneven rice cooking operation.

(Prior Art) As a rice cooker equipped with a timer device for performing a timer rice cooking operation, for example, the one described in Japanese Patent Publication No. 36-5435 is known. That is, the timer device disclosed in the above-mentioned publication takes out the output of the driving electric motor through a reduction mechanism, locks the main shaft to the final gear of this reduction mechanism via a friction plate, and sets the time on this main shaft. The knob and circular cam are connected. In this case, the time setting knob is provided with a time scale, thereby displaying the set time of the timer operation and the elapsed time of the timer operation. The circular cam has a notch on its outer periphery, and by switching the contacts on the outer periphery, it forms an energizing path to the rice cooking heater after a timer operation for a predetermined time. ing.

Further, as a rice cooker whose uneven operation is controlled by a timer, for example, a rice cooker having the following configuration has been considered. That is, in addition to the rice-cooking thermostat, an auxiliary thermostat for controlling the uneven operation is provided, and a motor-type timer is provided to operate the timer for a predetermined period of time. The temperature set on the auxiliary thermostat (approximately 100
The structure is such that the irregular operation of heating at a temperature (°C) continues for the timer operation time set in the timer.

(Problem to be Solved by the Invention) In each of the conventional rice cookers described above, the control accuracy is low because a mechanical timer is used to control the timer rice cooking operation or the uneven operation. There is a problem, and if the structure is configured to be able to perform both the timer rice cooking operation and the uneven rice cooking operation, two types of timer devices will be required, which will inevitably complicate the structure.

Furthermore, in a rice cooker configured to control uneven operation using a timer, if the thermal conductivity between the auxiliary thermostat and the pot varies due to processing accuracy and assembly accuracy, the operating temperature of the auxiliary thermostat This will result in an error. However, it is actually very difficult to provide a mechanism for correcting such errors, and normally the above-mentioned errors are allowed only within a predetermined range. For this reason, it is unavoidable that the heating temperature of the pot during the uneven operation will vary by the above error, which may cause the rice to burn during the uneven operation or the uneven effect may be insufficient. It could not be said that heating control was performed accurately.

The present invention has been made in view of the above circumstances, and its purpose is to enable timer rice cooking operation and uneven operation for a predetermined time to be performed with high precision without complicating the structure, and to control heating during uneven operation. An object of the present invention is to provide a rice cooker that can perform rice cooking accurately.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a temperature-sensitive resistance element that detects the temperature of the rice to be cooked, a timer rice cooking operation, and detection of the temperature-sensitive resistance element. A rice cooking control means that performs rice cooking control including an uneven operation based on the output, a first timer that measures a standby time for the timer rice cooking operation, and a second timer that measures the duration of the uneven rice cooking operation. In addition, the first and second time measuring means are configured by a microcomputer.

(Function) Since the temperature of the cooked rice is detected as a change in the resistance value of the temperature-sensitive resistance element, that is, an electrical variable that is the easiest to handle, the thermal conductivity between the cooked rice and the temperature-sensitive resistance element is Even if the temperature varies, the temperature detected by the temperature-sensitive resistance element can be compensated for very easily. Therefore, the heating control performed during the uneven operation based on the detection output of the temperature-sensitive resistance element becomes accurate.

Furthermore, since the first timer for measuring the standby time of the timer rice-cooking operation and the second timer for measuring the duration of the uneven rice-cooking operation are configured by a microcomputer, their control accuracy can be improved. At the same time, it is not necessary to provide two types of timer devices as in the prior art, and the structure can be simplified.

(Example) First, in FIG. 3, 1 is a substantially cylindrical outer case, 2 is a bottom frame fitted to the lower part of the outer case 1, 3 is an inner case disposed inside the outer case 1, and 4 5 is a heat insulating material interposed between the outer case 1 and the inner case 3, and 5 is a pot detachably attached to the inner case 3. Further, 6 is a rice cooking heater disposed at the inner bottom of the inner case 3, 7 is a heat-retaining heater wrapped around the upper outer periphery of the inner case 3, 8 is a lid rotatably supported on the outer case 1, and 9 is a locking mechanism that holds M8 in a locked state.

1O is a heat transfer cap provided so as to be pressed against the outer bottom of the pot 5 by the spring force of a spring (not shown), and a temperature sensitive resistance element such as a thermistor 11, for example, is disposed inside the cap for heat transfer. has been done. Therefore, this thermistor 11 measures the temperature of the rice to be cooked in the corresponding pot 5.
The temperature at the bottom of the pot (hereinafter referred to as pot bottom temperature) is detected, and the change in resistance value according to the detected temperature is output as a temperature information signal Sd.

In FIG. 4, reference numeral 12 denotes a clock device disposed on the outside of the outer case, which consists of a display section 13 for digitally displaying hours and minutes, and an operation section 14. Note that this clock device 12 has a normal clock function and a timer function for performing a well-known timer rice cooking operation, and selection and adjustment of each function is performed by each operation button 14a of the operation section 14. ing.

Reference numeral 15 denotes a heating pattern selection device disposed on the outside of the outer case 1, which has a plurality of operation buttons 15a, and these operation buttons 15a can be used to control rice cooking using five types of heating patterns, which will be described later. ``rice porridge'', ``koge'', ``takikomi''.

"Double cooking" corresponds to the uneven action in the present invention.

This is for selecting any one of the rice cooking controls of "keep warm", and outputs a pattern selection signal Sp that can specify the selected heating pattern.

Note that 16 is a display device disposed on the outside of the outer case 1, which has, for example, four display lamps 16a, each of which indicates the current operating state by lighting. At this time,
The display device 16 is "cooking rice".

The operating states of "double cooking", "uniform cooking", and "keep warm" are displayed.

Next, the electrical configuration will be explained according to FIGS. 1 and 2. First, in Figure 2 showing the outline of the electric circuit configuration, 17
is a bidirectional three-terminal thyristor (hereinafter simply referred to as a thyristor), and a series circuit of this and the rice cooking heater 6 is connected to receive power from a plug 18. Further, the heat-retaining heater 7 is connected in parallel with the thyristor 17, so when the thyristor 17 is turned off, the rice-cooking heater 6 and the heat-retaining heater 7 are energized in series, and each generates heat with a relatively small heat generation capacity. The pot 5 is heated with low heat, and when the thyristor 17 is turned on, only the rice cooking heater 6 is energized, which generates heat with a relatively large heat generation capacity, and the pot 5 is heated with high heat. Reference numeral 19 denotes a voltage regulator interposed in the current conduction path of the rice cooking heater 6;
The configuration is such that the amount of heat generated is adjusted by suppressing the voltage between the terminals. Note that the amount of heat generated by the rice cooking heater 6 does not necessarily have to be adjusted by the voltage regulator 19 as described above; for example, the phase control composition of the thyristor 17 can also be adjusted by on/off duty ratio control.

Therefore, the voltage regulator 19 has the same function as the thyristor 1.
7 and the clock device 12, it is controlled by a control circuit device 20 which is a rice cooking control means. As shown in FIG. 1, this control circuit device 20 includes a storage section 21.
It is configured as a microcomputer including a time control section 22 and an arithmetic processing section 23, which also serve as a first time measurement means and a second time measurement means. Five types of programs for predetermined control are stored corresponding to the rice cooking control according to the five types of heating patterns.

Further, the time control section 22 is provided to receive the clock pulse Pc from the oscillator 24, and has functions such as outputting a time information signal St for timing based on a command from the arithmetic processing section 23.

The arithmetic processing section 23 is provided to receive the temperature information signal Sd from the thermistor 11, the pattern selection signal Sp from the heating pattern selection device 15, and the time information signal St from the time control section 23 as data inputs. reads out a program corresponding to the input pattern selection signal sp from the storage section 21, controls the thyristor 17 and the voltage adjustment device 19 based on this readout program, the temperature information signal Sd and the time information signal St, and performs the following steps. The heating pattern is configured to obtain a heating pattern corresponding to the program. Further, the arithmetic processing section 23 also controls the clock device 12.

Now, in the following, among the five types of rice cooking control that the arithmetic processing unit 23 executes based on the program read from the storage unit 21, the case of "double cooking" corresponding to the uneven operation will be taken as an example. This will be explained with reference to the drawings. Furthermore, the fifth
In the figure, the horizontal and vertical axes are time T and pan bottom temperature D ("C
) is shown.

When the heating pattern selection device 15 selects a heating pattern for "double cooking" and outputs a pattern selection signal Sp, which is a rice cooking start command signal with which the heating pattern can be specified, the arithmetic processing section 23 Based on the program from the storage unit 21, the thyristor 17 is turned on to start the rice cooking operation, and the rice cooker heater 6 heats the pot 5 over high heat to boil the water in the pot 5.

During this boiling period, the temperature at the bottom of the pot is maintained at approximately 100° C., but when the water in the pot 5 evaporates and is absorbed by the rice, resulting in a so-called dry-up state, the temperature at the bottom of the pot rises rapidly. This causes the thermistor 11 to indicate the pot bottom temperature D-1.
When the temperature information signal Sd corresponding to 30° C. is output (time tl), the arithmetic processing unit 23 turns off the thyristor 17 to shift to uneven operation in response to this, and at the same time causes the time control unit to On the other hand, after 5 minutes have elapsed, the time information signal St
Issue a command to output. When the above-mentioned time information signal St is output at time t2, which is 5 minutes after this time tl, the arithmetic processing unit 23 that has received it outputs the signal from the thyristor 17.
is turned on for only one minute, and during this on period, the pot 5 is reheated over high heat to perform so-called Mitaka cooking, and thereafter the above-mentioned uneven operation is performed. In other words, when the predetermined condition that 5 minutes have passed after the end control of the rice cooking operation is satisfied,
The Mitaka cooking operation is controlled as described above, and as a result, excess water from the cooked rice is blown away, making the rice delicious.

Note that when the timer rice cooking operation is selected by the operation unit 14 of the clock device 12, the arithmetic processing unit 23 performs the timer operation for the time displayed on the display unit 13, and determines the start of the rice cooking operation according to the timer operation. It is designed to wait for a certain amount of time.

In this embodiment described above, a thermistor 11 is provided to detect the temperature of the rice to be cooked through the pot 5, and the end time of the rice cooking operation and the Mitaka cooking operation are determined based on the temperature information signal Sd corresponding to the internal resistance value change of the thermistor 11. It is characterized by a configuration that controls the start timing of. In other words, the temperature information signal S
Since d is based on the resistance value, which is the easiest to handle as an electrical variable, it can be easily corrected. As a result, the pot 5 and the heat-sensitive cap 10 are
Even if there are variations in the thermal conductivity between the thermal cap 10 and the thermistor 11, the temperature detected by the thermistor 11 corresponding to the temperature information signal Sd can be compensated very easily. Therefore, it becomes possible to accurately control the end time of the rice cooking operation and the start time of the Mitaka cooking operation (uniform operation) based on this end time. Moreover, since the temperature of the pot 5 can be continuously detected by the thermistor 11, it is possible to accurately control various operations such as "cooking porridge" and "cooking", which were not mentioned in the embodiment, and this is an added value as a rice cooker. can be easily increased.

In addition, since the timer function for elapsed standby time of the timer rice cooking operation and the timer barrel function for elapsed time elapsed the duration of the uneven operation are obtained by the micro combiator, these timer rice cooking operations and unevenness The control accuracy of the operation can be improved, and the structure can be simplified since there is no need to provide two types of timer devices as in the conventional case.

Furthermore, in the above-mentioned embodiment, no mechanical contact is required to detect the temperature of the pot 5, so there is no problem caused by wear of the contact.

[Effects of the Invention] According to the present invention, as is clear from the above description, there is a temperature-sensitive resistance element that detects the temperature of the rice to be cooked, and rice-cooking control including uneven operation based on the output of this temperature-sensitive resistance element. In addition, the first timer for measuring the standby time for the timer rice-cooking operation and the second timer for measuring the duration of the uneven rice-cooking operation are configured by a microcomputer. This provides an excellent effect in that the heating control during the cooking operation can be performed accurately, and the timer rice cooking operation and the uneven operation for a predetermined time can be executed with high precision without complicating the structure.

[Brief explanation of drawings]

The drawings are for explaining one embodiment of the present invention.
The figure is a block diagram of the electrical configuration, Figure 2 is a schematic electrical circuit diagram, Figure 3 is a partially cutaway front view of the whole, Figure 4 is a front view of the whole, and Figure 5 is for explanation of operation. FIG. In the figure, 5 is a pot, 6 is a rice cooking heater, 7 is a heat retention heater, and 11
1 is a thermistor (temperature-sensitive resistance element), 15 is a heating pattern selection device, 17 is a bidirectional three-terminal thyristor, 20 is a control circuit device (rice cooking control means), 21 is a storage section, and 22 is a time control section (first (timekeeping means, second timekeeping means), and 23 represents an arithmetic processing section.

Claims (1)

[Claims] 1. A temperature-sensitive resistance element that detects the temperature of the rice to be cooked; a rice-cooking control means that performs rice-cooking control including a timer rice-cooking operation and an uneven operation based on the detection output of the temperature-sensitive resistance element; and a second timer that measures the duration of the uneven motion, and the first and second timer are configured by a microcomputer. A rice cooker featuring: