JPS6365829A - Rice cooker - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a rice cooker in which a pot is heated by a rice cooking heater to perform a rice cooking operation.

(Prior art) In conventional rice cookers, in order to control the end time of rice cooking,
Switch devices that combine magnetic shunt steel, permanent magnets, operating levers, microswitches, etc. as temperature detection elements are widely used, and are also used as heating means for heating rice cookers with high output power. Heater (low internal resistance)
and a small-output heat-retaining heater (with a large internal resistance value). In this case, the rice-cooking heater is usually connected to both ends of the power plug via the microswitches in series, and the heat-retaining heater is usually connected to the microswitches in =lIj rows. In fact, a thermal relay is provided in order to maintain the temperature 11u maintained by the heat-retaining heater at a constant temperature, and this thermal relay is interposed in series with the current-carrying path of the heat-retaining heater.

The above switch device is generally configured as follows.

In other words, a heat-sensitive cap is provided that presses against the outer bottom of the rice-cooking pot when it is installed in a predetermined position. Inside this heat-sensitive cap, magnetic shunt steel, which loses its magnetism at a certain temperature, conducts heat. H<Hg steel detects 211 degrees of the food to be cooked as the temperature of the pot. At this time, the temperature at one point of the magnetic shunt steel is selected to be approximately equal to the temperature at which the rice is cooked (generally around 130'C). In addition, the operating lever is rotatable between three positions (■ A permanent magnet is mounted at the tip of the operating bar, and this operating lever can be used to adjust the permanent 61! The door is rotated to the first position where it is absorbed by the magnetic steel, and the door is returned to the second position in response to the release of the permanent magnet's absorption 9 as the magnetic shunt steel loses its magnetism. The microswitch is turned on when the control lever is rotated to the first position and turned off when the control lever is rotated to the second position.

Therefore, in a rice cooker equipped with a switch device as described in 1. (1.i), when the operating lever is rotated to the first position, the rotation state is a permanent magnet and a switch device 1i. J.
While being held by the suction degree 1 between EH, the microswitch is turned on, and in response, the rice cooking heater generates heat by human output and the rice cooking operation is started. After that, as the rice cooking operation continues, the inside of the pot exhibits a so-called dry-up condition, and the temperature of the magnetic shunt steel (detected temperature) rises to the level at which the rice is cooked.
When the temperature rises above 1-L and its magnetism disappears,
As the permanent magnet is released from the front, the operating lever is rotated back to the second position and the microswitch is turned off, so the rice cooking heater and the warming heater are energized in series, and the load current becomes extremely small, causing the internal resistance to decrease. The rice-cooking heater with a small value is in a substantially power-off state, and the heat retention operation is performed by the heat generated by the heat retention heater.

(Problem to be Solved by the Invention) The thermal conductivity between the outer bottom of the pot and the heat-sensitive cap, and the heat conductivity between the heat-sensitive cap and the magnetic shunt steel are determined by the addition of these parts, the accuracy and Because there is some variation due to assembly precision, etc., the 1. It is inevitable that an error will occur between the IA degree and the temperature detected by the magnetic shunt steel.

On the other hand, since the temperature at one point of magnetic steel is constant, the temperature of the pot when the magnetic steel loses its magnetism, that is, the temperature of the pot when the rice cooking operation is terminated by the switch device, is the temperature of the pot when the rice cooking operation is terminated by the switch device. It will vary depending on the device. As a result, in the conventional rice cooker, the end timing of the rice cooking operation may be inaccurately controlled.

As a means to deal with such problems, for example, it is possible to provide an adjustment mechanism to adjust the thermal conductivity of the magnetic shunt steel, but such a system! In practice, it is very difficult to provide a one-bar mechanism.

For this reason, conventionally, a predetermined tolerance of 1,! -i degree width is set, and quality control is carried out during the manufacturing of rice cookers so that the operation of the switch device 11M degrees falls within the tolerance range of 2 and 2 degrees.

In other words, in the conventional rice cooker, the actual situation is that the control of the end time of the rice cooking operation is relatively loose, and this point has been an unresolved problem.

Also, 1. In the conventional rice cooker, when the power plug is inserted into the power outlet, a series energization path is formed between the rice cooking heater and the warming heater, that is, the IAA state is established. Therefore, if the pot is left with the power plug plugged into the power outlet with powder and water stored in the pot, the warming operation will be performed inadvertently. In this case, especially when the ambient temperature is high, such as during summer, the temperature of the water in the pot will rise abnormally, which will have a negative effect on the rice inside, and the subsequent rice cooking will cause a strange odor to the cooked rice. This may cause problems such as sticking. To deal with such problems,
I wonder if it would be better to add a function to selectively perform the heat retention operation by external operation, but there were no rice cookers with such a function in the past.

Therefore, when starting or ending the warming operation,
The user had to perform the troublesome operation of inserting and removing the power plug each time, which made the device inconvenient to use.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to accurately control the end timing of the rice cooking operation, and to selectively execute the warming operation, thereby improving usability. To provide a rice cooker that has the following effects.

[Means of the invention] (Means for solving the problems) The present invention provides a heating means for heating a pot for cooking rice, and a temperature detection means for outputting a temperature information signal according to the temperature of the cooked rice. , an adjustment means for controlling the amount of heating by the heating means, and a control means for controlling the end of the rice cooking operation by the heating means based on the temperature information signal and a pre-stored program. The control means is configured to be capable of selectively executing a heat-retaining operation in which heating by the heating means is kept in a low state by the I-section means in response to an external operation.

(Function) The temperature information signal used to control the end timing of the rice cooking operation changes depending on the temperature of the cooked rice detected by the temperature detection means and is not fixed. Even if the thermal conductivity between the object and the temperature detection means varies, the temperature detected by the temperature detection means can be easily compensated for. Therefore, it becomes possible to accurately control the end timing of the rice cooking operation. In addition, the first stage of control controls the heating by the heating means to keep it in a low state. Since the operation is performed selectively, there is no risk that the heat-retaining operation will be performed carelessly as in the conventional case.

(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 l, 4 are outer case 1 and inner case 3
The heat insulating shrine 5 interposed between the two is a pot with an I, I, and Y mortar mounted inside the inner case 3. Further, 6 is a rice cooking heater which is a heating means disposed at the inner bottom of the inner case 3, 7 is a heat insulating heater which is also a heating means and is wrapped around the outer circumference of the inner case 3, and 8 is an outer heater. A lid 1 is rotatably supported, and a locking mechanism 9 holds the lid 8 in a locked state. 1
Reference numeral 0 denotes a heat transfer cap that is placed in pressure contact with the outer bottom of the pot 5 by the force of a spring (not shown). For example, a thermistor 11 serving as a FiA degree detection means is provided.

Therefore, this thermistor 11 detects the temperature of the cooked rice as the bottom temperature of the corresponding pot 5 (hereinafter referred to as the pot bottom temperature), and the resistance value C corresponding to the detected temperature is detected by the thermistor 11. The eclipse is output as a temperature information signal Sd.

Further, 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 a well-known timer switch, and selection and adjustment of each function is performed by each operation button 14a of the operation section 14. There is. Furthermore, 15 is also the outer case 1
This is a heating pattern selection device which is an operation means disposed on the outer side of the device, and has, for example, three operation buttons 15a, and these operation buttons 15a can be used to select a heating pattern for porridge cooking, a heating pattern for two-part cooking, and a heating pattern for two-part cooking, which will be described later. Any one of the heating patterns for keeping warm can be selected. At this time, the heating pattern selection device 15 outputs six pattern selection signals Sp capable of specifying the selected heating pattern. Incidentally, reference numeral 15b denotes an "off" button provided adjacent to the I- operation button 15a, which is set to +1 so that the warming operation is interrupted in response to the operation of this button. Further, 16 is a display device disposed on the outside of the outer case 1;
This includes, for example, four display lamps 16a, each of which lights up to indicate the current operating state.

At this time, the display device 16 displays "cooked rice", "double cooked",
It is designed to display the lip movements of "unevenness" and "keep warm".

Next, the electrical configuration will be explained according to FIGS. 1 and 2. First, in Figure 2, which shows the outline of the construction of the electric circuit +1,
17 is a bidirectional three-terminal thyristor (hereinafter simply referred to as thyristor), and a series circuit between this and the rice cooking heater 6 is 7.
It is connected to receive power from the u source plug 17a. Further, the heat-retaining heater 7 is connected to the thyristor 17 in the =lIli row, so when the thyristor 17 is turned off, the rice-cooking heater 6 and the heat-retaining heater 7 are energized in series, and the rice-cooking heater 6 is substantially cut off. The state is changed to 12, and the pot 5 is heated over low heat. Further, when the thyristor 17 is turned on, only the rice cooking heater 6 is energized, which generates heat with relatively human power and heats the pot 5 with high heat. 18 together with the thyristor 17:
This is a voltage regulating device that constitutes the setting stage 19, which is interposed in the energizing path of the rice cooking heater 6, and by suppressing the voltage between the ends of the rice cooking heater 6, its output makes the (heating meter) rise. It is the composition.

Note that the output amount of the rice cooking heater 6 does not necessarily need to be adjusted by the voltage regulator 18 as described above (for example, it can be adjusted in one phase by controlling the phase of the thyristor 17 or controlling the on/off duty ratio.

Thus, the 1-2 voltage regulator 18 is connected to the thyristor 17 and the time 5! The device 12 is controlled by a control circuit device 20 as a control means. As shown in FIG. 1, this control circuit device 20 includes a storage section 2
It is configured as a microcomputer including an 11-hour control section 22 and an arithmetic processing section 23, and a storage section 2.
1 stores three-pole programs (described later) for controlling the thyristor 17 and voltage regulator 18 in a predetermined manner in correspondence with the three types of heating patterns. Further, the time control section 22 is provided to receive the clock pulse Pc from the oscillator 24, and outputs a time information signal St for timing according to the command from the arithmetic processing section 23. Then, the arithmetic processing unit 23 receives the temperature information signal Sd from the thermistor 11, the pattern selection signal Sp from the heating putter 2 device, and the time control unit 23.
are provided to receive the time information signal St from the input pattern selection signal S as data input.
A program corresponding to p is read from the storage unit 21, and this read program and the temperature information signal Sd
・Thyristor 17 based on time information signal St.
and the voltage regulator 18, thereby obtaining a heating pattern corresponding to the program. Also,
The arithmetic processing section 23 also controls the clock device 12.

Now, below, the specific operation that the arithmetic processing section 23 executes based on the program read from the storage section 21 will be explained with reference to FIGS. 5 to 7 as well as the effects of each heating pattern. In addition, in FIG. 5(A) and FIG. 6, time T and pot bottom temperature D (
Figure 5 (B) shows the temperature characteristic curve corresponding to 'C).
7 shows temperature characteristic curves corresponding to the time T and the output P (W) of the rice cooking heater 6 on the horizontal and vertical axes, respectively.

(1) Heating pattern for cooking porridge (see Fig. 5) A heating pattern for cooking porridge is selected by the heating pattern selection device 15, and a pattern selection signal Sp is output that allows the heating pattern to be specified. And the performance processing section 2
3 turns on the thyristor 17 to energize only the rice cooking heater 6 based on the program from the storage unit 21. Therefore, the pot 5 is heated over high heat and the bottom temperature of the pot rises relatively rapidly, and the thermistor 11 detecting this, outputs the change in its resistance value as a temperature information signal Sd. Then, when the temperature information signal Sd corresponding to the pot bottom temperature D-80° C. is output at time t1, the eX calculation processing section 23 operates the voltage regulator 18 in accordance with this to control the amount of heat generated by the rice cooking heater 6. The power is controlled to about 100 watts, and the pot 5 is heated over low heat. This causes the bottom temperature of the pot to rise relatively slowly. Then, when the pot bottom temperature Bo reaches 98°C (time t2)
, the arithmetic processing section 23 issues a command to the time control section 22 to output the time information signal St after 20 minutes have elapsed.

When the above-mentioned time information signal St is output at time t3, which is 20 minutes after this time tz, the arithmetic processing unit 23 that has received it cancels the operation of the voltage regulator 18 and simultaneously turns off the thyristor 17. The rice cooking heater 6 and the heat-retaining heater 7 are energized in series, and the pot 5 is further heated over a low heat, thereby shifting to an uneven operation. By the action described above, the rice stored in the water and river in the pot 5 can be cooked into porridge. In particular, during such "cooking porridge", the pot 5 is heated at a low heat of about 100 W from time t2 when the bottom temperature of the pot reaches 98°C to time t3, so that the cooking temperature in the pot 5 is - will not boil over due to excessive boiling.

(n) Heating pattern for double-cooking (see Figure 6) A heating pattern for double-cooking is selected by the heating pattern selection device 16, and the rice-cooking start command signal is used to specify the heating pattern. When the barrel pattern selection (≦ Sp is output, the arithmetic processing section 23 turns on the thyristor 17 to start the rice cooking operation based on the program from the input section 21, and the rice cooking heater 6 cooks the rice in 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 the water in the pot 5 evaporates and is absorbed by the rice, causing so-called boiling. When a dry-up condition occurs, the temperature at the bottom of the pot rises rapidly.

As a result, the thermistor 11 indicates the pot bottom temperature D - 130°C.
When the temperature information signal Sd corresponding to is output (time t4
), the arithmetic processing section 23 turns off the thyristor 17 in response to this and shifts to uneven operation, and at the same time instructs the time control section 22 to output the time information signal St after 5 minutes have elapsed. put out. When a series of time information signals St are output at time t, which is 5 minutes after time t4, the arithmetic processing unit 23 that has received this outputs the thyristor 17.
The pot 5 is turned on for a minute, and during this on period, the pot 5 is reheated over high heat to perform so-called two-part cooking, and thereafter, the above-mentioned uneven cooking is performed. In other words, when the predetermined condition that 5 minutes have passed after the end of the rice cooking operation is satisfied,
The double-cooking operation is controlled as described above, and as a result, excess moisture in the cooked rice is evaporated, making the rice delicious.

(III) Heating pattern for keeping warm (see Figure 7) This heating pattern is for keeping rice, etc.
When a heat retention heating pattern is selected by 5 and a pattern selection signal Sp is output that allows the heating pattern to be specified, the ei calculation processing section 23 turns off the thyristor 17 based on the program from the storage section 21. When this state is maintained, the control voltage by the voltage 1 adjustment device 19 is maintained at a constant value at 11:. As a result, a maintenance operation is performed in which the outputs of the rice cooking heater 6 and the warming heater 7 are suppressed to a low level, and the pot 5 is heated over low heat.

10. In the embodiment described above, the automatic transition to the uneven motion 1.
Time-based fa ES when a predetermined period of time has passed after being
It is also possible to use a configuration in which a buzzer or the like is sounded by 11.

As described in 1-, this embodiment is provided with a thermistor 11 that detects the temperature of the rice to be cooked through the pot 5, and based on the temperature information signal Sd from the thermistor 11, the heating pattern for porridge cooking and the double cooking are set. The present invention is characterized in that it is provided with a control circuit device 20 that selectively executes control of heating patterns for use and selectively executes a heat-retaining operation based on a pattern selection signal Sp from a pattern selection device. At this time, since the temperature information signal Sd is based on the resistance value, which is the easiest to handle as an electrical variable, it is F+J function to easily correct this. As a result, during manufacturing, the space between the pot 5 and the heat-sensitive cap 10 as well as the heat-sensitive cap 1
Even if the respective thermal conductivities between 0 and the thermistor 11 vary, the temperature detected by the thermistor 11 corresponding to the 2Iu degree information signal can be compensated very easily. Therefore, in addition to controlling the end time of the rice cooking operation,
It becomes possible to accurately control the rice cooking operation for cooking porridge as described in the embodiment. Further, since a microswitch having a conventional mechanical contact point is not required to detect the temperature of the pot 5, problems such as shortened lifespan due to wear of the contact point are not caused. Moreover, since the control circuit device 20 is configured to selectively execute the heat retention operation, the heat retention operation is not started simply by inserting the power plug 17a into the 7-power outlet; Usability will be improved since this will not be done carelessly.

[Effects of the Invention] According to the present invention, as is clear from the above explanation, two types of cooked limbs are detected and the 21u temperature is adjusted according to the detected temperature.
Output information signal? The amount of heating by the H degree detection means and the heating means for heating the pot is adjusted. adjustment means, as well as the above)
Control means for controlling the end of the rice cooking operation by the self-heating means according to 1λ based on a temperature information signal and a pre-stored program are respectively provided, and the first control stage is controlled by the heating layer by the heating L stage. 1. It is possible to selectively perform a heat-retaining operation of keeping the temperature at a low level using the adjusting means in accordance with an external operation.1. Since the rice cooker has a ljj structure, it is possible to more accurately control the end timing of the rice cooking operation and improve the reliability of the service life.Furthermore, the lk1 operation can be selectively executed by external operation, making it easy to use. This has the excellent effect of making it possible to improve the situation.

[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 partly cutaway diagram of the entire 11 parts, and Figure 4 is a schematic diagram of the electrical configuration.
The figure is a front view of the whole, Figure 5 (A) is a temperature characteristic diagram to explain the action, Figure 5 (B) is an output characteristic diagram to explain the action, and Figure 6 is the '+ilA I' diagram to explain the action. Characteristic diagram, Fig. 7 is an output characteristic diagram for explaining the function. In the figure, 5 is a pot, 6 is a rice cooking heater (heating means) 7 is a heater
1A heater (IJII heat means), 11 is a thermistor (
temperature detection means), 15 is a heating pattern selection device, 17 is a bidirectional three-terminal sirisk, 18 is a voltage regulator, 19
20 is a control circuit device (control unit 0 stage); 21 is an adjustment means;
22 represents a storage unit, 22 represents a time control unit, and 23 represents an arithmetic processing unit. Applicant Toshiba Corporation Figure 1 Figure R Figure 82 Figure 37

Claims (1)

[Claims] 1. A heating means for heating a pot for cooking rice, a temperature detection means provided to detect the temperature of the rice to be cooked and outputting a temperature information signal according to the detected temperature, and the amount of heating by the heating means and a control means for controlling the end of the rice cooking operation by the heating means based on the temperature information signal and a pre-stored program, the control means controlling the amount of heating by the heating means. A rice cooker characterized in that the rice cooker is configured to be able to selectively perform a heat-retaining operation to maintain the temperature at a low level by means of an external operation.