JPH021487B2 - - Google Patents

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, a switch device that combines magnetic shunt steel as a temperature detection element, a permanent magnet, an operating lever, a micro switch, etc. is widely used to control the end time of rice cooking. Such a switch device is generally constructed 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 Curie point temperature, conducts heat. The temperature of the rice to be cooked is detected as the temperature of the pot using the magnetic shunt steel. At this time, the Curie point temperature of the magnetic shunt steel is selected to be approximately equal to the temperature at which rice is cooked (generally around 130° C.). In addition, a permanent magnet is attached to the tip of an operating lever that is rotatable between two positions, and this operating lever is capable of attracting the permanent magnet to magnetic shunt steel in response to an external operation. While being rotated to the first position, it is rotated back to the second position in response to the permanent magnet being released from attraction as the magnetic shunt steel loses its magnetism. The micro switch 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, and in the on state, the rice cooking heater is turned on. The configuration is such that an electric path is formed.

Therefore, in a rice cooker equipped with a switch device configured as described above, when the operation lever is rotated to the first position, the rotation state is changed due to the attraction between the permanent magnet and the magnetic shunt steel. At the same time, the micro switch is turned on, and in response, the rice cooking operation by the rice cooking heater is started. After this, as the rice cooking continues, the inside of the pot exhibits a so-called dry-up state, and when the temperature (detected temperature) of the magnetic steel becomes higher than the rice cooking temperature and its magnetism disappears, the permanent magnet's attraction is released. Accordingly, the operating lever is rotated back to the second position and the micro switch is turned off, so that the rice cooking heater is cut off and the rice cooking operation is completed.

(Problem to be solved by the invention) In the above conventional rice cooker, the temperature that can be detected by the switch device is only 130°C, which corresponds to the Curie point temperature of magnetic shunt steel, so it can only perform normal rice cooking. . That is, when trying to cook rice porridge in a rice cooker, the output of the rice heater is reduced before the inside of the pot reaches a boiling state, thereby preventing the cooking liquid in the pot from boiling rapidly. It is necessary to control the soup so that it does not boil over, but with conventional rice cookers, it is impossible to detect when the inside of the pot is just before boiling, so it is impossible to do so without causing the rice porridge cooking soup to boil over. It is possible.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a rice cooker that has effects such as being able to perform porridge cooking control in addition to normal rice cooking control without causing overcooked rice. .

[Structure of the invention]

(Means for Solving the Problems) The present invention includes a temperature detection means for detecting the temperature of the rice to be cooked, and controls the end of the rice cooking operation by a rice cooking heater for heating a pot based on the temperature detected by the temperature detection means. The control means includes a time control section that generates a time information signal for timing, and controls the rice cooking heater at high output until the temperature detected by the temperature detection means reaches a certain temperature. The rice porridge cooking control is configured to generate heat and then selectively execute porridge cooking control in which the rice cooking heater is made to generate heat at a small output for a certain period of time based on the time information signal from the time control section.

(Function) The control means is capable of controlling not only the normal rice cooking operation but also the porridge cooking operation, and during the porridge cooking control, the rice cooking heater is turned on at high speed until the temperature detected by the temperature detection means reaches a certain temperature. In addition to generating heat through the output, the rice cooking heater is then controlled to generate heat at a small output for a certain period of time based on the time information signal from the time control section. Therefore, when cooking porridge, the cooking liquid in the pot is prevented from boiling excessively, thereby eliminating the possibility that the cooking liquid in the pot will boil over.

(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, and 3
4 is a heat insulating material interposed between the outer case 1 and the inner case 3; 5 is an inner case disposed within the outer case 1;
is a pot detachably mounted inside 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 the lid 8 in a locked state. Reference numeral 10 denotes a heat transfer cap which is provided in pressure contact with the outer bottom of the pot 5 by the force of a spring (not shown), and inside thereof there is a temperature detecting means, such as a thermistor 11, which is thermally conductive with the cap.
is installed. Therefore, this thermistor 11
is the temperature of the food to be cooked in the pot 5 that corresponds to this.
(hereinafter referred to as pot bottom temperature D), and a change in resistance value corresponding to the detected temperature is output as a temperature information signal Sd.

In addition, in Fig. 4, 12 is a clock device disposed on the outside of the outer case, which indicates the hours and minutes.
It consists of a display section 13 that digitally displays the information, 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 each function is selected and adjusted using the operation section 14.
This is done using each operation button 14a. Further, reference numeral 15 denotes a heating pattern selection device also disposed on the outside of the outer case 1, which has two operation buttons 15a in a row. It is possible to select any heating pattern for the porridge cooking operation. At this time, the heating pattern selection device 15 is configured to output a pattern selection signal Sp that can specify the selected heating pattern. In addition, 15b is an "off" button provided adjacent to the operation button 15a.
The rice-cooking operation and the porridge-cooking operation are configured to be interrupted in response to the button's operation.
Reference numeral 16 denotes 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 process currently being executed when lit. At this time, the display device 16 displays "cooking",
Each step of ``double cooking'', ``uniform heating'', and ``keep warm'' is displayed.

Next, the electrical configuration will be explained with reference to FIGS. 1 and 2. First, in FIG. 2 showing the outline of the electric circuit configuration, 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 receives power from the plug 17a. It is connected. 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 output. 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 at a relatively high output, and the pot 5 is heated with high heat. Reference numeral 18 denotes a voltage regulator that constitutes the power supply control means 19 together with the thyristor 17, which is interposed in the current conduction path of the rice cooking heater 6 and adjusts its output by suppressing the voltage between the terminals of the rice cooking heater 6. It is a structure that encourages Note that the output of the rice cooking heater 6 does not necessarily need to be adjusted by the voltage regulator 18 as described above, and for example, by using the thyristor 17.
It can also be adjusted by phase control or on/off duty ratio control.

Thus, the voltage regulator 18, together with the thyristor 17 and the clock device 12, is controlled by a control circuit device 20 serving as a control means. As shown in FIG. 1, this control circuit device 20 is configured as a microcomputer including a storage section 21, a time control section 22, and an arithmetic processing section 23, and the storage section 21 includes a thyristor 17 and Two types of programs (described later) for controlling the voltage regulator 18 in a predetermined manner are stored corresponding to the two types of heating patterns. Further, the time control section 22 is connected to the oscillator 2.
4, and outputs a time information signal St for timing based on a command from the arithmetic processing section 23. and,
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, respectively. Input pattern selection signal
reads a program corresponding to Sp from the storage unit 21, and controls the thyristor 17 and the voltage regulator 18 based on this read program and the temperature information signal Sd and time information signal St;
In this way, a heating pattern corresponding to the program can be obtained. Further, the arithmetic processing section 23 is adapted to also control 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 and 6 as well as the effects of each heating pattern. In addition, FIGS. 5A and 6 show temperature characteristic curves corresponding to time T and pot bottom temperature D (°C) on the horizontal and vertical axes, respectively, and FIG. 5B shows temperature characteristic curves on the horizontal and vertical axes, respectively. A temperature characteristic curve corresponding to time T and output P (W) of the rice cooking heater 6 is shown.

()... Heating pattern for porridge cooking operation (see Figure 5) The heating pattern selection device 15 selects a heating pattern for porridge cooking operation, and the pattern selection signal allows the heating pattern to be identified.
When Sp is output, the arithmetic processing unit 23 turns on the thyristor 17 and energizes only the rice cooking heater 6 based on the program from the storage unit 21. Therefore, since the rice cooking heater 6 generates heat at a high output, the pot 5 is heated with high heat and the bottom temperature D of the pot rises relatively rapidly, and the thermistor 11 detects this and outputs the change in its resistance value as a temperature information signal Sd. Output as . Then, at time t ₁ , the pot bottom temperature D
When the temperature information signal Sd corresponding to =80°C is output, the arithmetic processing unit 23 operates the voltage regulator 18 in accordance with this to adjust the output of the rice cooking heater 6.
Heat the pot 5 over low heat, controlling the temperature to about 100 watts. As a result, the pot bottom temperature D is raised relatively slowly. Then, when the pot bottom temperature D reaches 98°C (time t ₂ ), the arithmetic processing unit 23 sends the time information signal St to the time control unit 22 after 20 minutes.
Issue a command to output. after this time t ₂
At time t ₃ after 20 minutes, the above-mentioned time information signal St
is output, the arithmetic processing unit 23 that receives it
At the same time as the operation of the voltage regulator 18 is canceled, the thyristor 17 is turned off to energize the rice cooking heater 6 and the heat-retaining heater 7 in series, thereby shifting to an uneven operation in which the pot 5 is further heated over low heat. Due to the above-described actions, the rice stored in the pot 5 together with an appropriate amount of water can be cooked into porridge. In particular, during such "cooking porridge", the pot 5 is heated over a low heat of about 100 watts from time t ₂ when the pot bottom temperature D reaches 98°C to time t ₃ . This prevents the soup from boiling over due to excessive boiling.

() ……Heating pattern for normal rice cooking operation (6th
(See figure) When the heating pattern selection device 16 selects a heating pattern for the normal rice cooking operation and outputs a pattern selection signal Sp, which is a rice cooking start command signal that can identify the heating pattern, the arithmetic processing unit 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 cooking heater 6 heats the pot 5 over high heat to boil the water in the pot 5. During this boiling period, the bottom temperature D of the pot is maintained at approximately 100℃,
When the water in the pot 5 evaporates and is absorbed by the rice, resulting in a so-called dry-up state, the bottom temperature D of the pot rises rapidly. As a result, when the thermistor 11 outputs the temperature information signal Sd corresponding to the pot bottom temperature D=130°C (time t ₄ ), the arithmetic processing unit 23 turns off the thyristor 17 in response to this and shifts to uneven operation. At the same time, a command is issued to the time control section 22 to output the time information signal St after 5 minutes have elapsed. this time t ₄
When the above-mentioned time information signal St is output at time _t5 , which is 5 minutes later, the arithmetic processing unit 23 that receives this turns on the thyristor 17 for only 1 minute, thereby turning on the pot 5 during this on period. The rice is reheated over high heat to perform so-called twice-cooking, and then the above-mentioned shading operation is performed. In other words, when a predetermined condition is established that 5 minutes have passed after the end of the rice cooking operation, the double cooking operation is controlled as described above, and as a result, the excess moisture in the cooked rice is removed. The food becomes delicious when it is blown away.

In the above embodiment, the time control section 11 may be configured to cause the time control section to sound a buzzer or the like when a predetermined time has elapsed after shifting to the irregular operation.

As described above, in this embodiment, the thermistor 11 is provided to detect the temperature of the rice to be cooked through the pot 5, and the temperature information signal Sd from the thermistor 11 is provided.
The present invention is characterized in that it is provided with a control circuit device 20 that selectively executes the normal rice cooking operation and the porridge cooking operation based on the above-mentioned control circuit device 2.
0 is the pot bottom temperature D when controlling porridge cooking.
until the rice reaches a constant temperature of 80°C.
The rice cooker heater 6 is controlled to generate heat at a high output and thereafter generate heat at a low output for a predetermined period of 0 minutes. As a result, when cooking porridge, the situation in which the cooking liquid in the pot 5 boils rapidly is prevented, and the cooking liquid in the pot 5 is prevented from boiling over. Further, since it is sufficient to provide the thermistor 11 to obtain the temperature information signal Sd for controlling the rice cooking operation and the porridge cooking operation as described above, there is no need to waste parts or complicate the structure. be. Moreover, the temperature information signal Sd is
Since it is based on the resistance value, which is the easiest to handle as an electrical variable, it can be easily corrected. As a result, even if the thermal conductivities between the pot 5 and the heat-sensitive cap 10 and between the heat-sensitive cap 10 and the thermistor 11 vary, the temperature detected by the thermistor 11 corresponding to the temperature information signal Sd can be very easily detected. can be compensated. Therefore, it becomes possible to accurately control each heating pattern described above, and the added value of the rice cooker can be easily increased. Further, since a micro switch having a conventional mechanical contact point is not required to detect the temperature of the pot 5, there is no need for any inconvenience caused by wear of the contact point.

〔Effect of the invention〕

According to the present invention, as is clear from the above description, temperature detection means for detecting the temperature of the cooked rice;
and a control means for controlling the end of the rice cooking operation by the rice cooking heater for heating the pot based on the temperature detected by the temperature detection means, and the control means is controlled so that the temperature detected by the temperature detection means reaches a certain temperature. It is possible to selectively execute porridge cooking control in which the rice-cooking heater generates heat at a high output until then, and thereafter the rice-cooker heater generates heat at a low output for a certain period of time based on the time information signal from its own time control unit. Because of this configuration, it is possible to perform not only normal rice cooking control but also porridge cooking control without boiling over the cooked liquid, and it is also possible to simplify the structure and improve the accuracy of each of the above-mentioned controls. It has excellent effects.

[Brief explanation of drawings]

The drawings are for explaining one embodiment of the present invention, and FIG. 1 is a block diagram of the electrical configuration, FIG. 2 is a schematic electrical circuit diagram, and FIG. 3 is a partially cutaway front view of the entire device. Figure 4 is a front view of the whole, Figure 5A is a temperature characteristic diagram to explain the effect, Figure 5B is an output characteristic diagram to explain the effect, and Figure 6 is a temperature characteristic diagram to explain the effect. . In the figure, 5 is a pot, 6 is a rice cooking heater, 7 is a heat retention heater, 11 is a thermistor (temperature detection means), 15 is a heating pattern selection device, 17 is a bidirectional three-terminal thyristor, 18 is a voltage regulator, and 19 is a Power supply control means, 20 is a control circuit device (control means), 2
1 is a storage section, 22 is a time control section, and 23 is an arithmetic processing section.

Claims (1)

[Claims] 1. A rice cooker heater for heating a rice cooking pot;
A temperature detection means provided to detect the temperature of the rice to be cooked; and a control means for controlling termination of the rice cooking operation by the rice cooking heater based on the temperature detected by the temperature detection means, the control means comprising: It has a time control unit that generates a time information signal for timing, and causes the rice cooking heater to generate heat at high output until the temperature detected by the temperature detection means reaches a certain temperature, and after that, the time control unit generates heat. A rice cooker characterized in that it is configured to be able to selectively execute porridge cooking control in which a rice cooking heater generates heat at a low output for a certain period of time based on a time information signal.