JP4026620B2 - Cooking device - Google Patents

Description

  The present invention relates to a cooker that heats an object to be cooked while adjusting the pressure in the pan.

  When the cooking pressure such as cooking rice is increased by increasing the pressure in the pan, moisture 80 and soup stock can sufficiently penetrate into the food to be cooked, and cooking can be completed in a short time. Therefore, the pressure cooker as a cooker which heats a to-be-cooked object, adjusting the pressure in a pan is conventionally known.

  In general, the pressure in a pressure cooker is adjusted so that when the pressure in the pan becomes too high, the weight in the pan is lifted using the pressure in the pan while the amount of heating to the pan remains unchanged. , By discharging steam to the outside of the pan, or by adjusting the closing time or opening time of the opening communicating with the inside or outside of the pan by the pressure adjusting means for adjusting the pressure in the pan, or the pressure adjusting means is left as it is In this state, it was done by adjusting the amount of heating to the pan. However, in these methods, in order to adjust the inside of the pan to a desired pressure, it was necessary to determine the heating amount, the closing time, and the opening time of the pan while repeating the experiment many times.

For such a problem, for example, Patent Document 1 discloses that a pot that accommodates an object to be cooked is heated by a heating coil that is a heating means, and at the same time, a lid that covers the opening of the pot so that the opening can be opened, that is, a lid. A lid temperature sensor, which is a lid temperature detecting means for detecting the temperature in the pot, a pressure sensor as a pressure detecting means for detecting the pressure in the pot, and a pressure regulator as a pressure adjusting means for adjusting the pressure of the pot There is disclosed a pressure cooker that includes each of the pressure regulators, and the pressure regulator includes a pressure regulation ball disposed above an opening communicating with the inside and outside of the pan, and a solenoid that is a driving means for the pressure regulation ball. Here, before the cooking of rice or at the beginning of cooking, the pressure adjusting ball is pressed by the plunger of the solenoid, the pressure adjusting ball is retracted from the opening, and the inside of the pan is maintained in a state substantially the same as the atmospheric pressure. After that, when the pressure cooking is performed, the pressure from the plunger to the pressure adjusting ball is released. Therefore, in the state where the opening is closed by the weight of the pressure adjusting ball, the pressure in the pan becomes high, and the pressure in the pan is When the predetermined set value is exceeded, the steam in the pan lifts the pressure adjusting ball and discharges the steam to the outside. In that case, according to the pressure in the pan detected through the pressure sensor, the amount of energization to the heating coil is controlled so that the pressure in the pan is within a predetermined range, and pressure rice cooking control is performed.
JP 2000-325229 A

  In the pressure cooker as shown in the above-mentioned patent document 1, in order to maintain the inside of the pan at a predetermined pressure, the control means varies the amount of heating to the pan based on the detection information from the pressure sensor. However, since such a pressure sensor is expensive and the number of monitoring targets increases, there are problems such as a complicated control program executed by the control means.

  In view of the above problems, an object of the present invention is to provide a pressure cooker capable of appropriately adjusting the pressure in the pan with an inexpensive configuration that does not use a pressure sensor.

  In the cooker according to claim 1 of the present invention, when the rate of increase in the detected temperature from the temperature detection means for detecting the temperature in the lid and the pan is reduced to a predetermined value or less while the pressure of the pan is lowered during cooking, At that time, it is judged that the inside of the pan has almost boiled, and the temperature detected by the temperature detecting means is set as the reference temperature.

  Here, since there is a correlation between the temperature and pressure when the inside of the pan is in a boiling state, the pressure in the pan can be grasped to some extent from the temperature detected by the temperature detecting means without using a pressure sensor. However, since there are actually variations in characteristics of the individual temperature detection means, even if the temperature detection means of the temperature detection means at the time of boiling is the same, the pressure in the pan differs individually. Therefore, if the pressure in the pan is detected by the relative temperature of how much the detected temperature of the current temperature detection means is different from the reference temperature when it is judged that the inside of the pan is almost boiled, individually Even the temperature detecting means having characteristic variation can detect the pressure of the pan more accurately and variably adjust the sealing degree and thus the pressure in the pan to an appropriate state by the adjusting means.

  In the cooking device according to the second aspect of the present invention, it is determined that the inside of the pan is almost boiled, and the temperature detected by the temperature detecting means is set as the reference temperature, and then the temperature detected by the temperature detecting means reaches the first temperature. When the temperature rises, the heating decreases. Conversely, when the temperature decreases to the second temperature, the heating increases. Thus, the pressure in the pan at the time of cooking can be maintained within an appropriate range by adjusting the amount of heating together with the degree of sealing after detecting boiling.

  In the cooking device according to the third aspect of the present invention, after determining that the inside of the pan is substantially boiled and setting the detected temperature of the temperature detecting means as the reference temperature, the detected temperature of the temperature detecting means reaches the first temperature. When the temperature rises, the sealing means is lowered by controlling the adjusting means, and conversely, when the temperature is lowered to the second temperature, the airtightness is raised. Thus, the pressure in the pan at the time of cooking can be maintained within an appropriate range by adjusting the degree of sealing after detecting boiling and adjusting the amount of heating as in claim 2 in some cases.

  In the cooker according to claim 4 of the present invention, the first temperature and the first temperature which are changing points for increasing or decreasing the sealing degree or the heating amount according to the cooking course selected by the selecting means or the cooking amount estimated by the estimating means. Since one or both of the two temperatures can be changed, it is possible to perform optimum pressure cooking in accordance with a desired cooking course and cooking amount.

  In the cooking device according to claim 5 of the present invention, the degree of sealing until the temperature detected by the temperature detecting means reaches the first temperature according to the cooking course selected by the selecting means or the amount of cooking estimated by the estimating means, Since either one or both of the sealing degrees until the second temperature is reached can be changed, optimum pressure cooking according to a desired cooking course and cooking amount can be performed.

  In the cooking device according to claim 6 of the present invention, when the temperature detected by the temperature detecting means rises to a third temperature that cannot be normal, the heating is reduced or stopped. By doing so, it is possible to reliably prevent the inside of the pan from rising to an abnormal pressure.

  In the cooker according to the seventh aspect of the present invention, since various processes in the control means are executed at high speed by the digital signal processor, it is possible to finely control the pressure in the pan.

  According to the cooking device of claim 1 of the present invention, it is possible to adjust the pressure in the pan appropriately by relatively judging the detection temperature of the lid temperature detection means with an inexpensive configuration that does not use a pressure sensor. become.

  According to the cooker in claim 2 of the present invention, the pressure in the pan at the time of cooking can be maintained within an appropriate range by adjusting the heating amount together with the sealing degree after the boiling detection.

  According to the cooker in claim 3 of the present invention, the pressure in the pan at the time of cooking can be maintained within an appropriate range by adjusting the sealing degree after detection of boiling, and by adjusting the heating amount in some cases. it can.

  According to the cooker in claim 4 of the present invention, it is possible to perform optimum pressure cooking according to a desired cooking course and cooking amount.

  According to the cooker in claim 5 of the present invention, it is possible to perform optimum pressure cooking according to a desired cooking course and cooking amount.

  According to the cooking device in claim 6 of the present invention, it is possible to reliably prevent the inside of the pan from rising to an abnormal pressure.

  According to the cooker in claim 7 of the present invention, the pressure in the pan can be finely controlled.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the cooking device here is a rice cooker of the pressure control system which has a rice cooking and heat retention function.

  The basic configuration of the rice cooker in the present embodiment will be described with reference to FIG. 1. Reference numeral 1 denotes a main body serving as an outer shell of the rice cooker. The main body 1 includes a substantially cylindrical outer frame 2 and an outer frame 2. And a bottom plate 3 provided so as to cover the lower surface opening. On the upper side of the container main body 1, a lid, that is, a lid body 5 is rotatably supported by a hinge shaft 4 serving as a hinge located at the rear portion thereof. In addition, the container is constituted by a substantially cylindrical pot accommodating portion 6 formed by hanging integrally from the upper inner peripheral portion of the outer frame 2 and an inner frame 8 provided so as to cover the lower surface opening of the pot accommodating portion 6. A bottomed cylindrical pot housing 9 is formed in the main body 1. In addition, the pot accommodating part 6 which makes the side part of the pot accommodating body 9 consists of synthetic resins, such as PP (polypropylene) integrated with the outer frame 2. As shown in FIG. The inner frame 8 that forms the bottom of the pot housing 9 is made of a synthetic resin such as FR-PET (polyethylene terephthalate) and has a shape that is substantially similar to the outer shape of the pot 11 described later.

  You may comprise the main body external appearance of a cooking appliance by the outer frame which integrated the upper part and the side part, ie, the outer frame 2, and the baseplate 3 which covers the bottom part of the outer frame 2. As shown in FIG. Further, the main body appearance is configured by an upper frame that covers the upper part and a bottom side frame that integrates the side part and the bottom part, or an upper frame that covers the upper part, a side frame that covers the side part, and a bottom plate that covers the bottom part. You may comprise by. At that time, the outer frame, the bottom plate, the top frame, and the bottom side frame are all formed of a synthetic resin such as PP, but the side frame may be formed of a synthetic resin such as PP or a metal plate such as stainless steel. May be formed.

  In the pot housing 9, a bottomed cylindrical pot 11 for storing an object to be cooked such as rice or water is detachably accommodated. This pan 11 has a pan body 12 mainly made of aluminum with good thermal conductivity, and a ferritic stainless steel integrally formed by, for example, molten metal forging from the lower side to the bottom of the outer surface of the pan body 12. And a heat generating layer 13 made of a magnetic metal material. The reason why the heating layer 13 is not provided from the center to the top of the side surface of the pan 11 is to reduce the weight of the pan 11. An annular flange portion 14 is formed around the upper end of the pan 11 so as to extend to the outer periphery thereof.

  The inner frame 8 is located opposite to the heat generating layer 13 of the pan 11, but the bottom of the pan 11, particularly the bottom, is electromagnetically placed on the lower and bottom sides of the inner frame 8 facing the heat generating layer 13. A heating coil 16 is provided as a heating means for induction heating. The heating coil 16 is spirally wound around and fixed to the outer surface of the inner frame 8 while facing the heat generating layer 13 on the outer surface of the pan 11. When a high-frequency current is supplied to the heating coil 16 from an inverter circuit of the heating control means 71 described later, an eddy current is generated in the heat generating layer 13 in the magnetic field by the alternating magnetic field generated from the heating coil 16. The eddy current is converted into Joule heat, so that the heat generating layer 13 generates heat, and the pot 11 and thus the food to be cooked such as water and rice in the pot 11 are heated. Further, a ferrite core 17 is provided so as to cover the heating coil 16 from below.

  A pan temperature sensor 21 serving as a pan temperature detecting means that elastically contacts the bottom outer surface of the pan 11 and detects the outer surface temperature of the pan 11 is supported by a sensor holder 22 at the center of the bottom of the inner frame 8. Is provided. The pan temperature sensor 21 is preferably composed of a negative characteristic thermistor, and mainly controls the outer surface temperature of the pan 11 by the heating coil 16.

  The lid body 5 is fixed to a hinge shaft 4 that is a rotating shaft thereof, and is biased in a direction to open the hinge shaft 4 as a fulcrum by the force of a hinge spring 23 wound around the hinge shaft 4. Reference numeral 24 denotes an open / close button of the lid 5, which is integrally formed with a lid locking portion 25 extending upward inside the lid 5 and is attached to the outer frame 2 of the container body 1. On the back side of the open / close button 24, there is provided a compression spring (not shown) that generates a repulsive force when the open / close button 24 is pressed. When the open / close button 24 is pressed against the elasticity of the compression spring, the open / close button 24 The opening / closing button 24 and the lid locking part 25 are both rotated about the rotation shaft 26 of the button 24.

  The lid 5 is formed by, for example, a plastic outer lid 31 that forms an upper shell of the lid 5, a lid lower surface material 32 that forms the lower surface of the lid 5, and the outer lid 31 and the lid lower surface material 32 that are joined together. An outer lid cover 33 as a lid base material forming the skeleton of the body 5 is a main component. An inner lid 35 that directly covers the upper opening of the pan 11 is detachably mounted under the lid lower surface material 32 so as to form a predetermined gap with the lid lower surface material 32. Both the lid lower surface material 32 and the inner lid 35 are made of metal, and are made of, for example, a metal material anodized with stainless steel or aluminum. A packing base 36 is fixed to the outer periphery of the inner lid 35, and a lid packing 37 is fixed between the packing base 36 and the inner lid 35. The lid packing 37 is formed in an annular shape by an elastic member such as silicone rubber or fluorine rubber, and abuts against the upper surface of the flange portion 14 of the pan 11 to close the gap between the pan 11 and the inner lid 35. The steam generated from 11 is sealed. Then, the inner lid 35 is attached by inserting the protruding portion 38 provided on the packing base 36 into the insertion hole 39 on the front side of the outer lid cover 33, and a hooking portion provided on the rear side of the outer lid cover 33 ( The packing base 36 is hooked and fixed to the not shown). In this state, the tip of the projecting portion 38 engages with the upper portion of the lid locking portion 25. Therefore, when the lid 5 is closed, the lid locking portion 25 is engaged and held on the device body 1 side. When the open / close button 24 is pushed in a state where the lid 5 is closed, the open / close button 24 and the lid locking part 25 rotate together around the rotation shaft 26 of the opening / closing button 24, and the lid locking part 25 And the protrusion 38 are disengaged, and the lid 5 is automatically opened by the force of the hinge spring 23. On the other hand, when the inner lid 35 is not attached, the projecting portion 38 is not engaged with the lid body locking portion 25, so that even if the lid body 5 is closed, the lid body latching portion 25 remains in the main body 1. It is not engaged and held on the side.

  A steam port 41 that can be attached and detached from above the lid body 5 is provided at the upper rear portion of the lid body 5. The outer lid 31, the outer lid cover 33, and the lid lower surface material 32 below the steam port 41 have holes so that the steam can be discharged, respectively, so that the steam does not enter the inside of the lid 5. Has been. As a result, a steam passage 42 is formed inside the lid 5 to release steam generated from the inside of the pan 11 to the outside of the lid 5.

  On the other hand, the inner lid 35 is provided with a ball pedestal 44 having an opening 43 for exhausting the steam in the pan 11 at the bottom, and on the upper surface side of the inner lid 35 opposite to the pan 11, and opens and closes the opening 43. A pressurizing mechanism 47 including a pressure adjusting ball 45 placed on the ball pedestal 44 and a dome-shaped cap 46 that regulates the movement range of the pressure adjusting ball 45 is provided, and faces the upper surface of the pan 11. The pressure in the pan 11 includes a mounting seat 50 having a hole 49, a valve body 51 that normally closes the hole 49 by a biasing force of a spring (not shown), and a cover 52 that closes the upper opening of the mounting seat 51. When the pressure is increased to an abnormal pressure that is greater than or equal to the set value for some reason, a safety valve 53 is provided that pushes up the valve body 51 against the spring and opens the hole 49 to lower the internal pressure of the pan 11. The pressurizing mechanism 47 and the safety valve 53 are provided facing the inlet side of the steam passage 42 when the inner lid 35 is attached to the lower side of the outer lid cover 33. Further, the peripheral portions of the pressurizing mechanism 47 and the safety valve 53 are attached to the lid lower surface material 32 and sealed by an inner lid packing 55 protruding from the inner lid 35 to the inner lid packing 55. The steam having passed through the opening 43 and the hole 49 is directly directed from the steam passage 42 to the steam port 41 without hitting the lid lower surface material 32.

  58 is a solenoid provided as a pressure adjusting means provided inside the lid body 5 to adjust the sealing degree of the lid body 5, that is, the internal pressure of the pan 11 by moving the pressure adjusting ball 45. More specifically, the solenoid 58 faces a side opening of the cap 46 constituting the pressurizing mechanism 47 and is laterally provided on one side of the lid case member 59 provided on the inner side of the lid lower surface member 32. At the same time, a plunger 60 as a movable portion protruding toward the pressure adjusting ball 45 is disposed in a state of being covered with a sealing material 61 such as rubber. In this embodiment, when the solenoid 58 is not energized, the plunger 60 is held in the advanced position, and the pressure adjusting ball 45 is retracted from the opening 43, while the plunger 60 is retracted in the energized state to adjust the pressure adjusting ball 45. Is caused to roll into the opening 43 by its own weight, and pressure is introduced into the pan 11. Note that the position of the plunger 60 when the solenoid 58 is energized / de-energized may be the reverse of this embodiment.

  The lid lower surface material 32 is provided with a hole 64 in addition to the hole 63 through which the pressurizing mechanism 47 and the safety valve 53 are inserted, and a lid temperature detection for detecting the temperature of the lid 5, particularly the inner lid 35 and thus the inside of the pan 11. As a means, a thermistor-type lid temperature sensor 65 protrudes toward the inner lid 35 therefrom. The lid temperature sensor 65 is configured by accommodating a sensor body 66 made of a negative characteristic thermistor in a stainless steel sensor holder 67 having a material thickness of preferably 0.2 to 0.5 mm. The sensor holder 67 is movable up and down 3 to 10 mm and has a structure that is pressed against the upper surface of the inner lid 35 by a sensor spring (not shown) (the pressing amount pressed against the inner lid 35 is 2 to 5 mm, even in the pressed state) It has a margin of about 1 to 5 mm). The clearance between the hole 64 and the surrounding part of the sensor holder 67 is about 0.5 to 3 mm. Even if the sensor holder 67 slightly deviates from the center position of the hole 64, the surrounding part touches the hole 64 and is offset. The sensor holder 67 reliably contacts the inner lid 35 to detect the temperature. Further, the bottom surface of the tip of the sensor holder 67 is concave, so that point contact with the inner lid 35 is reliably prevented.

  Inside the lid 5, a lid heater 68 as a lid heating means is provided on the upper surface of the lid lower surface material 32. The lid heater 68 may be an electric heating heater such as a cord heater or a heating coil by electromagnetic induction heating. Further, a heating control means 71 is provided in the interior rear of the vessel body 1, and this heating control means 71 comprises a heating element (not shown) for driving a heating coil 16 as a heating means on the substrate. Is done.

  Next, an electrical configuration in this embodiment is shown in FIG. In the figure, a display / operation unit 75 around an operation panel (not shown) provided on the outer surface of the main body 1 or the lid 5 is two microcomputers as control means for controlling the operation of each part of the rice cooker. (Microcomputer). This is a display microcomputer 76 as a first control unit and a load driving microcomputer 77 as a second control unit. The display microcomputer 76 is an 8-bit microcomputer, and the processing speed is slower than that of the load-driven microcomputer 77. However, it has low power consumption, and in addition to the input / output unit, storage unit, and control processing unit normally provided as a microcomputer, It is characterized by having a drive control circuit for the LCD 28 provided in the operation unit 75. In particular, a lithium battery of about 600 mAh, which is generally used as the built-in battery 78, is used because the power consumption when the power supply to the main unit 1 is cut off is less than 10 μA during a power failure. If so, the current consumption of the peripheral circuit connected to the display microcomputer 76 can be maintained for 4 years or more without replacement. Using these characteristics, the display microcomputer 76 performs display processing on the LCD 28 including memory backup at the time of a power failure, time count of a clock function, time, and the like. In particular, the display microcomputer 76 also manages the operation of the entire pressure cooker because the memory backup is performed by receiving the power supply from the battery 78 even during a power failure. In addition, the display microcomputer 76 performs pressure processing related to LED 29 display processing, switch 30 depression detection and processing based on this detection, power failure detection and processing based on this detection, and cooking and heat retention. The entire vessel is controlled.

  The switch 30 as the operation means is also provided in the display / operation unit 75. Specifically, the rice cooking switch 30a for instructing the start of rice cooking and the quick cooking to shorten the rice cooking time than usual. A quick cooking switch 30b to instruct, a course switch 30c and a cooking switch 30d as course selection means, a time switch 30e for instructing to change the time digit of the current time or reservation time displayed on the LCD 28, and the current time or reservation time A minute switch 30f for instructing to change the minute digit, a reservation switch 30g for instructing reserved rice for starting or ending rice cooking at the reservation time, and a turn-off switch 30h for instructing a turned-off state for canceling the rice cooking or heat retaining operation are provided . In this example, the course according to the difference in rice quality such as white rice, non-washed rice, brown rice, germinated brown rice and the same rice quality (white rice), such as sweetness, softness, crispness, and firmness. The course switch 30c and the cooking switch, which are cooking course selection means, are provided with courses according to differences in taste, etc., and courses according to differences in cooking while having the same rice quality (white rice) such as porridge and cooking When 30d is operated, a specific course is selected from the plurality of courses.

  In addition, the LCD 28 as a display means displays the current time or the reservation time, displays a course selected from courses according to the difference in rice quality and cooking, and displays that fact at the time of heat insulation and reheating. Or has the function of displaying the hardness of the cooked rice or the degree of taste. The content of the course here is merely an example, and various other courses may be provided. Furthermore, LED29 displays each operation | movement, such as rice cooking, quick-cooking rice cooking, heat retention, a reservation, and is comprised by several light emitting elements.

  In order for the display microcomputer 76 to perform processing based on power failure detection, whether or not the power supply from the commercial power source (not shown) to the main unit 1 is cut off at the input side port of the display / operation unit 75 is determined. A power failure detection circuit 79 for detecting is provided. When a power failure signal indicating that a power failure has been detected is sent from the power failure detection circuit 79, the display microcomputer 76 that has received this backs up the built-in memory and stores the state immediately before the power failure in each part of the pressure cooker. It is supposed to be. Further, the switch 30 is connected to the input side port of the display microcomputer 76, and the LCD 28 and the LED 29 as display means are connected to the output side port of the display microcomputer 76, respectively.

  On the other hand, another load driving microcomputer 77 is a 32-bit DSP (digital signal processor) microcomputer, which consumes more current than the display microcomputer 76 but has a very high speed digital signal processing function. is there. Utilizing such characteristics, IH control related to the heating coil 16 that requires high-speed processing, particularly in a rice cooker, and processing that requires a lot of calculation during rice cooking are performed. For this purpose, the input side port of the load drive microcomputer 77 detects the input voltage, input current, and regenerative current of the inverter that are input to the inverter, and outputs a detection signal to the inverter and the like. A surge detection circuit 82 that detects an unnecessary surge voltage that is generated and a trigger detection circuit 83 that outputs a trigger signal that is the oscillation timing of the heating coil 16 are connected, and the output side port of the load driving microcomputer 77 An inverter oscillation circuit 84 that supplies a high-frequency current to the heating coil 16 is connected. In addition, the load driving microcomputer 77 reads the temperature information from the pan temperature sensor 21 and the lid temperature sensor 65, and controls the driving of the loads 88 other than the heating coil 16, such as the lid heater 68 and the solenoid 58. Yes. For this purpose, a temperature detection circuit 85 that outputs sensor outputs from the pan temperature sensor 21 and the lid temperature sensor 65 as temperature information is connected to the input side port of the load drive microcomputer 77, and the output side of the load drive microcomputer 77 Connected to the port is a load drive circuit 86 that supplies sufficient power to drive the load 88. Each of these circuits 81 to 86 is provided as a heating circuit 89 that constitutes the heating control means 71.

  As described above, the reason why the plurality of microcomputers 76 and 77 are used as the control means is that, in general, a microcomputer having a high processing speed (for example, the load driving microcomputer 77) consumes a large amount of current. In other words, in this embodiment, a lot of calculations are required to read and process information from each part of the rice cooker, but when trying to perform data backup and clock counting at the time of power failure with a high-speed microcomputer that can process such calculations. This is because a battery having a large capacity is required to operate the microcomputer even in the event of a power failure, resulting in a problem of increasing costs and increasing the size of the main body 1. Therefore, the driving control of the heating coil 16 and the load 88 that require high-speed processing is configured to be executed by the load driving microcomputer 77 having a high-speed calculation function, and control of other parts of the pressure cooker (especially, power failure) The display microcomputer 76 having a low current consumption function is configured to execute a backup function that still requires power consumption.

  In order to exchange signals between the two microcomputers 76 and 77, in this embodiment, each of the microcomputers 76 and 77 is provided with a communication unit 90 that realizes three-wire clock synchronous serial communication. The display microcomputer 76 is provided with a clock generation unit 91 that generates a reference clock pulse. From the clock generation unit 91 of the display microcomputer 76 to the load driving microcomputer 77 having a high processing speed, the communication unit 90 is connected. By outputting a clock, communication is synchronized on the load driving microcomputer 77 side. The display microcomputer 76 gives various command signals to the load driving microcomputer 77 when, for example, cooking rice or keeping warm. Specifically, an IH drive command signal indicating how much power the heating coil 16 is driven, a panless detection command signal for checking the presence / absence of the pan 11, and a process of boiling heating 2 described later are executed. For example, a load driving command signal indicating how to drive the load 88 or the like is transmitted to the load driving microcomputer 77 via the communication unit 90. On the contrary, the load drive microcomputer 77 transmits temperature information obtained from the temperature detection circuit 85, IH drive error information related to the heating coil 16, and the like to the display microcomputer 76 via the communication unit 90.

  In addition to the serial communication line 92 connected between the communication units 90, a reset transmission line 93 for transmitting a reset signal from the display microcomputer 76 to the load driving microcomputer 77 is provided between the display microcomputer 76 and the load driving microcomputer 77. Connected. The display microcomputer 76 is provided with a reset unit 94 that generates a reset signal for returning the load driving microcomputer 77 from the idle mode to the normal mode. As described above, since the load driving microcomputer 77 consumes more current than the display microcomputer 76, the load driving microcomputer 77 has a circuit configuration in which no current is supplied to the load driving microcomputer 77 during a power failure. Therefore, when the power supply to the main unit 1 is cut off, the display microcomputer 76 receives the current supply from the battery 78 and operates as it is, but the load driving microcomputer 77 stops operating and consumes no current at all. . Thereby, the consumption of the battery 78 at the time of a power failure can be suppressed to the minimum. In addition, even during energization when power is supplied to the main body 1, during a period when the heating coil 16 and the load 88 do not need to be driven, such as when stopped (off state) or when waiting for reserved cooking, When, for example, 5 to 60 seconds) elapses, the display microcomputer 76 sends a command to set the load driving microcomputer 77 from the normal mode to the idle (pause) mode by serial communication, thereby setting the load driving microcomputer 77 in the low power consumption state.

  As described above, when the load driving microcomputer 77 enters the idle mode after a certain time has elapsed, the information from the voltage / current detection circuit 81 and the temperature detection circuit 85 is transmitted to the display microcomputer 76. This is because the determination of abnormality cannot be made and it is necessary to confirm them in the normal mode for a certain period of time. The load driving microcomputer 77 in the idle mode is released by the reset signal given from the reset unit 94 of the display microcomputer 76, and returns to the normal mode in which information from the voltage / current detection circuit 81, the temperature detection circuit 85, and the like is received. By providing the display microcomputer 76 with a function as the reset unit 94, it is possible to save an increase in cost of separately providing a reset circuit. Moreover, since the idle mode can be easily canceled by the reset signal from the display microcomputer 76, the programs of both the microcomputers 76 and 77 can be simplified. In addition, even when some communication abnormality occurs between the communication lines 92, a reset signal can be output from the reset unit 94 of the display microcomputer 76 to return the load driving microcomputer 77 to the initial state. This communication abnormality refers to a case where the display microcomputer 76 cannot receive a communication message due to noise or the like. If a communication error occurs during rice cooking, the load driving microcomputer 77 cannot be stopped by communication from the display microcomputer 76, so the load driving microcomputer 77 is reset by a reset signal from the display microcomputer 76. In addition, the reset signal is output from the display microcomputer 76 to the load driving microcomputer 77 when the power is restored.

  The heating control means 71 receives temperature detection signals from the pan temperature sensor 21 and the lid temperature sensor 65, and adjusts the heating coil 16 and the lid heater 68, which are heating means, respectively. During cooking and warming, the pan 11 is heated by these heating means.At the time of warming, the heating means is adjusted according to the temperature detected by the pan temperature sensor 21 in contact with the bottom of the pan 11, and the pan 11 is kept at a constant temperature. It is configured to hold.

  Each course selected by the course switch 30c and the cooking switch 30d has its own temperature change value and heating time from rice to peanut performed by the rice cooking control means 95, which will be described later, depending on the quality and hardness of the rice. Is set to For example, in the recommended (normal) course, the cooked rice is kept at 35 to 45 ° C for 20 minutes in the process, and until boiling it is about 8 ° C per minute (8 ° C / min), that is, the cooked rice is from 20 ° C to 100 ° C. The target is set so that it takes about 10 minutes to raise the temperature, and the boiling continues for another 5 to 10 minutes. In addition, in the crushing course, the holding time in the process is shorter than the recommended course, and until boiling, about 10 ° C per minute (10 ° C / min), that is, the cooked rice from 20 ° C To raise the temperature to 100 ° C, the target is set to be about 8 minutes shorter than the recommended course, the amount of heating to continue boiling more than the recommended course, and the unevenness time to be shorter than the recommended course. Also, in the soft rice course, the holding time in the process is longer than the recommended course, and until boiling it is about 5 ° C (5 ° C / minute), that is, the cooked rice is heated from 20 ° C to 100 ° C. The target is set to be about 16 minutes longer than the recommended course, lower the amount of heating to continue boiling than the recommended course, and make the unevenness time longer than the recommended course. Furthermore, in the sweetness course, the above-mentioned holding time in the process is lengthened so that the temperature range in which amylase works (for example, 40 to 50 ° C.) is kept long and about 4 ° C. (4 ° C.) per minute until boiling. / Min), that is, to raise the cooked rice from 20 ° C to 100 ° C, increase the working time of the enzyme as about 20 minutes longer than the soft rice course, reduce the amount of heating to continue boiling, and even more uneven And set a goal to increase the time.

  In addition, for courses such as brown rice and rice crackers, the process time, the amount of heating to the pan 11 and the temperature change value until boiling are set independently. Such target set values for the heating time and the temperature change value are merely examples, and may be appropriately changed in consideration of the heating capability and characteristics of the rice cooker, the characteristics of the temperature detection means, and the like.

  Further, as will be described later, the heating control means 71 is configured so that the sealing degree of the lid 5 adjusted by the solenoid 58 can be changed according to the course selected by the course switch 30c or the cooking switch 30d.

  Next, the effect | action is demonstrated about the said structure, referring the graph in FIG. In FIG. 3, the horizontal axis is each control process and elapsed time of rice cooking, the detected temperatures P1 and P2 of the pan temperature sensor 21 and the lid temperature sensor 65, the heating amount of the heating coil 16 (IH heating amount), The pressure in the pan 11 (1 atm = 1.01325 bar) and the state of the solenoid 58 as a pressure switch are shown. Each of the microcomputers 76 and 77 includes a rice cooking control means 95 and a heat retention control means 96 as functions on the software, and each control process of rice cooking and heat retention described later is held by the storage unit of these microcomputers 76 and 77. Processing is sequentially executed in accordance with a control program related to the rice cooking control means 95 and the heat retention control means 96.

  After the pan 11 filled with a predetermined amount of rice and water is housed in the pan housing 9 and the lid 5 is closed, the rice cooking switch 30a is pushed. When the input signal from the rice cooker switch 30a is taken into the display microcomputer 76, rice cooking by the rice cooking control means 95 is started, and first a process for infiltrating water to the core of the rice is performed. In the first stroke, the heating coil 16 is cut off in a predetermined pattern, the pan 11 is first heated, and then the heating is stopped for a certain time. And the capacity | capacitance determination means 97 with which the rice cooking control means 95 was equipped based on the raise value of the detection temperature P1 from the pan temperature sensor 21 at the time of initial heating, and the fall value of the detection temperature P1 at the time of a subsequent heating stop, The rice cooking capacity in 11 (cooking amount) is determined. That is, this capacity determination means 97 determines that the rice cooking capacity in the pan 11 is larger as the increase value of the detected temperature P1 at the initial heating and the decrease value of the detected temperature P1 at the time of heating stop are more gradual. In addition, it is determined that the rice cooking capacity in the pan 11 is smaller as the rising value of the detected temperature P1 at the time of initial heating and the lowering value of the detected temperature P1 at the time of heating stop are steep.

  When the capacity determination is completed, the rice cooking control means 95 controls the heating coil 16 to be turned on and off so that the detected temperature P1 of the pan temperature sensor 21 is maintained at a constant temperature, and causes the rice in the pan 11 to absorb water. Then, after a predetermined holding time corresponding to the above-described course has elapsed, the process is terminated and the process proceeds to a boiling heating process. In the meantime, during the stroke, the solenoid 58 is turned on to retract the plunger 60.

  At the beginning of the boiling heating process (refer to boiling heating 1 in FIG. 3), first, full energization is performed at 1100 to 1300 W, which is the maximum output of the heating coil 16, and the temperature increase rate during that time is read from the pan temperature sensor 21. The rice cooking control means 95 detects empty cooking in the pan 11 and the pan temperature sensor 21 detects abnormality. Even in the boiling heating 1, the solenoid 58 is continuously maintained in the ON state.

  Thereafter, regardless of the rice cooking capacity, when the boiling heating 1 is 70 seconds or more, which is a predetermined time, or the detected temperature P1 of the pan temperature sensor 21 is 70 ° C. or more, the rice cooking control means 95 performs the next boiling heating 2 To do. When the boiling heating 2 is entered, the rice cooking control means 95 first sets the target temperature Ta of the lid temperature sensor 65 based on the following equation (1).

上記数１において、目標温度Ｔａは、単位時間当たりの温度上昇率ａと、沸騰加熱２の開始時からの経過時間（単位：秒）ｔとの積に、沸騰加熱２の開始時における蓋温度センサ65の検知温度Ｔ₀を加えて算出される。これにより、ある時間ｔ毎における目標温度Ｔａが定まる。目標温度上昇率ａは前述の選択したコースや炊飯容量によって異なり、例えば硬めの炊き上がりをさせるコースでは大きな値（急な温度勾配）となり、やわらかめの炊き上がりをさせるコースでは小さな値（なだらかな温度勾配）となる。なお、目標温度ａとして蓋温度センサ65を用いるのは、鍋温度センサ21で検出する鍋11の底面の温度よりも、蓋温度センサ65で検出する内蓋35の温度が、鍋11内の被炊飯物の温度に近いためである。即ち、加熱コイル16により鍋11を電磁誘導加熱するものでは、鍋11の発熱層13が直接発熱するので、鍋11内部との温度差が大きいが、内蓋35は加熱コイル16による熱影響を直接受けないので、その分被炊飯物の温度を精度よく検出できる。但し、鍋温度センサ21の検知温度Ｐ１と鍋11内部の温度との相関が予め判っていれば、鍋温度センサ21を目標温度と定めて加熱制御を行なってもよい。また、時間ｔと目標温度Ｔａとの相関は、前記数１に示すものに限られない。

In the above equation 1, the target temperature Ta is the product of the temperature increase rate a per unit time and the elapsed time (unit: seconds) t from the start of the boiling heating 2, and the lid temperature at the start of the boiling heating 2 It is calculated by adding the detection temperature T ₀ of the sensor 65. Thereby, the target temperature Ta for every certain time t is determined. The target temperature increase rate a varies depending on the selected course and rice cooking capacity. For example, the target temperature increase rate a has a large value (steep temperature gradient) in a hard cooking course, and a small value (smooth) in a soft cooking course. Temperature gradient). The lid temperature sensor 65 is used as the target temperature a because the temperature of the inner lid 35 detected by the lid temperature sensor 65 is higher than the temperature of the bottom surface of the pot 11 detected by the pan temperature sensor 21. This is because it is close to the temperature of the cooked rice. That is, in the case where the pan 11 is electromagnetically heated by the heating coil 16, the heat generation layer 13 of the pan 11 directly generates heat, so the temperature difference from the inside of the pan 11 is large, but the inner lid 35 is affected by the heat effect of the heating coil 16. Since it is not directly received, the temperature of the cooked rice can be accurately detected accordingly. However, if the correlation between the detected temperature P1 of the pan temperature sensor 21 and the temperature inside the pan 11 is known in advance, the pan temperature sensor 21 may be set as the target temperature and the heating control may be performed. Further, the correlation between the time t and the target temperature Ta is not limited to that shown in the above equation 1.

  When the rice cooking control means 95 sets the target temperature Ta, the rice cooking control means 95 reads the target temperature at which the detected temperature P2 of the lid temperature sensor 65 read every predetermined time (for example, 1 second) is a set temperature change value. The output control of the heating coil 16 based on the following equation 2 is performed along Ta.

上記数２において、今回加熱コイル16に与える出力ワットＷ_n+1（Ｗ_nは前回加熱コイル16に与えた出力ワット）は、沸騰加熱２の開始時に加熱コイル16に与えた出力ワットに、各回毎に計算される調整ワットδＷを加えて算出される。また調整ワットδＷは、比例制御による調整ワットδＷ_pと、積分制御による調整ワットδＷ_iと、微分制御による調整ワットδＷ_dとをそれぞれ加算して算出される（δＷ＝δＷ_p＋δＷ_i＋δＷ_d）。なお、調整ワットδＷの要素としては、各調整ワットδＷ_p，δＷ_i，δＷ_dの少なくとも何れか一つが含まれていればよい。

In the above equation 2, the output wattage W _{n + 1} (W _n is the output watt previously given to the heating coil 16) given to the heating coil 16 this time is the same as the output watt given to the heating coil 16 at the start of boiling heating 2 each time. It is calculated by adding the adjustment wattage δW calculated every time. The adjusted watt δW is calculated by adding the adjusted watt δW _p by proportional control, the adjusted watt δW _i by integral control, and the adjusted watt δW _d by differential control, respectively (δW = δW _p + δW _i + δW _d ). . As an element of the adjustment watt δW, at least one of the adjustment watts δW _p , δW _i , and δW _d may be included.

The adjusted wattage δW _p by proportional control is the difference between the target temperature Ta at the current time point (t = n) calculated by Equation 1 and the actual detected temperature P2 read from the lid temperature sensor 65 (e _n = Ta-P2), and if the constant that determines how much the target temperature Ta, which is the target value, is approached by K _p , the adjustment watt δW _p is equal to the constant K _p and the temperature difference represented by product of _{e n (δW p = K p} × e n). Accordingly, as the difference between the target temperature Ta and the detection temperature P2 at this time is large, even larger values of the adjustment watts .delta.W _p calculated in proportion to this, the pot 11 quickly the target temperature Ta The output watt control of the heating coil 16 so as to approach is performed at regular time intervals when the detection temperature P2 of the lid temperature sensor 65 is taken.

The adjustment wattage δW _i by integral control is the difference between the target temperature Ta up to the past i times and the actual detected temperature P2 read from the lid temperature sensor 65 when the detected temperature P2 is read from the lid temperature sensor 65 this time. Adjustment constant wattage δW, where K _i is a constant that determines how much the target temperature Ta, which is the target value, approaches the target temperature Ta, and is an adjustment amount proportional to the total sum of (Σe _ni = Σ (Ta−P2)). _i is represented by the product of the cumulative total of Sigma] e _ni temperature difference and the constant _{K i (δW p = K p} × e n). As a result, the larger the integrated sum Σe _ni of the difference between the target temperature Ta and the detected temperature P2 up to a certain time ago, the larger the value of the adjusted wattage δW _i calculated in proportion to this. Considering the accumulation of the difference between the temperature Ta and the detected temperature P2, the output wattage control of the heating coil 16 that quickly brings the inside of the pan 11 close to the target temperature Ta takes a certain time to capture the detected temperature P2 of the lid temperature sensor 65 Every time. In particular, the only adjustment watts .delta.W _p by proportional control, when calculating the output wattage W _{n + 1} to the heating coil 16, but results in errors in the actual pot 11 internal temperature and the target temperature Ta that changes from moment to moment, If the adjustment wattage δW _i by integration control is taken into account, the output watt W _{n + 1} is calculated in consideration of the accumulation of the difference between the target temperature Ta and the detected temperature P2 in the past several times. Thus, it becomes possible to approach the target temperature Ta.

The adjustment watts .delta.W _d by differential control, when reading the detected temperature P2 from the current lid temperature sensor 65, and this current actual value obtained by subtracting the detected temperature P2 from the target temperature Ta (e _n), the last m times the difference between the - _(m e _n) actual a subtracted value detected temperature P2 of the front past m times from the previous target temperature Ta - an adjustment amount which is proportional to (e _n -e _{n m),} is the target value When a constant that determines how close in how much strength the target temperature Ta and K _d, the adjustment watts .delta.W _d is the the constant K _d difference (e _n -e _n - _m) indicated by the product of (.delta.W _{d = K d × (e n -e} n - m)). The difference (e _n -e _n - _m) is how much momentum indicates whether approaching the target value of the momentum to approach the target temperature Ta is low, adjustment watts calculated in proportion to If the value of δW _d increases and conversely the momentum approaching the target temperature Ta is strong, the value of the adjustment watt δW _d is set to suppress the actual temperature in the pan 11 from exceeding the target temperature Ta and overshooting. Make it smaller. Thus, in consideration of the momentum in which the temperature in the pan 11 approaches the target temperature Ta, the output watt control of the heating coil 16 that quickly brings the inside of the pan 11 close to the target temperature Ta is used to set the detection temperature P2 of the lid temperature sensor 65 to This is done at regular intervals.

The calculation of the target temperature Ta for each predetermined time and the calculation of the respective adjusted watts δW _p , δW _i , δW _d and the output watt output watt W _{n + 1} at that time are all arithmetic processing units of the load control microcomputer 77 (see FIG. (Not shown). When performing such calculation, the display microcomputer 76 sends the load control microcomputer 77 a command to perform boiling heating 2 and the control parameters thereof include the target temperature increase rate a and the constants K _p , K _i , K _d. Send.

  FIG. 4 conceptually shows the control method of the rice cooking control means 95 in the present embodiment. In this figure, in this embodiment, a target temperature Ta with time t as a parameter is set in advance, and the output watt of the heating coil 16, that is, the amount of heating to the pan 11 is brought close to the target temperature Ta that changes every time t. However, it is variably controlled every time the temperature inside the pan 11 is read. Therefore, conventionally, for example, fixed output watts of about 10 stages (for example, 500 W, 600 W, 700 W... 1400 W) are prepared in advance, and data for outputting the output watts (the ON time width and amplitude of the pulse applied to the oscillation circuit 83) However, in this example, the data for calculating the output watt is calculated every time the temperature inside the pan 11 is read, and the output watt of the heating coil 16 is not calculated. Variable in stages. For example, when an output watt of 630 W is required, 600 W and 700 W of the conventional data table are interpolated to calculate data for outputting the output watt. In this way, in this embodiment, regardless of the amount of cooked rice, the temperature in the pan 11 can be brought close to the target temperature Ta, and the actual heating by the heating coil 16 can be made to substantially match the ideal heating.

  In the boiling heating 2 described above, the rice cooking control means 95 is loaded from the voltage / current detection circuit 81 using the load driving microcomputer 77 until the detection temperature P2 of the lid temperature sensor 65 changes from 60 ° C. to 80 ° C. Based on the input voltage and input current of the inverter, the power consumption (integrated power consumption) of the heating coil 16 is calculated. The calculation result of the integrated electric energy calculated by the product of the input voltage, the input current, and time is transmitted to the display microcomputer 76 through the serial communication line 92 as needed. When the display microcomputer 76 receives this via the communication unit 90, the display microcomputer 76 stores it in the internal storage unit. When the power supply to the main unit 1 is interrupted due to a power failure, the accumulated power amount data by the load driving microcomputer 77 is cleared, but the display microcomputer 76 receives the power supply from the battery 78 and stores the stored contents in the storage unit. Since the power is continuously held, the correct integrated power amount can be obtained by adding the integrated power amount before the power failure stored in the storage unit to the integrated power amount by the load driving microcomputer 77 after the recovery from the power failure.

  Further, since the output watts of the heating coil 16 controlled by the load driving microcomputer 77 are adjusted one by one at the time of factory shipment, the actual output watts do not greatly change. In the present embodiment, the output watt adjustment of the heating coil 16 is performed by operating the switch 30 in a special pattern to activate a special mode different from the normal rice cooking and heat retention operations. The output adjustment means 98 provided as a power source operates, and a pulse that causes the heating coil 16 to output at a rated watt (for example, 1250 W) is driven by a load under the condition that a rated power supply voltage (for example, AC 100 V) is supplied to the main unit 1. It is supplied from the microcomputer 77 to the oscillation circuit 83. At this time, the output watt of the heating coil 16 is calculated from the input voltage and input current taken in from the voltage / current detection circuit 81, and the on-time width and amplitude of the pulse are adjusted so that this becomes the rated watt. Then, software adjustment (correction) is performed by the output adjustment means 98 so that the adjusted pulse is recognized as a drive signal to the oscillation circuit 83 at the rated watt hour. However, this may be performed in hardware by a variable resistor that adjusts the amount of current to the heating coil 16.

  In the subsequent rice cooking and heat insulation performed by the rice cooking control means 95 and the heat retention control means 96, when performing output at a certain watt, a pulse having an appropriate on-time width and amplitude calculated based on the drive signal is sent to the oscillation circuit 83. Supply. Even if the power supply voltage fluctuates, the actual output watt at this time is read from the voltage / current detection circuit 81, and the on-time width and amplitude of the pulse to the oscillation circuit 83 are varied so that this becomes the watt to be output. The output watt of the heating coil 16 is kept constant. By doing so, it becomes possible to supply the heating amount to the pan 11 with a correct wattage output regardless of the fluctuation of the power supply voltage.

  The calculated integrated power amount of the heating coil 16 may be used for reconfirmation of the rice cooking capacity by the rice cooking control means 95. The reason is that the amount of accumulated electric power until the detected temperature P2 changes from 60 ° C. to 80 ° C. depends on the size of the rice cooking capacity in the pan 11. For example, if it is determined that the rice cooking capacity is small in the above-mentioned process, but it is reconfirmed that the rice cooking capacity is large due to the integrated power consumption calculated thereafter, there may be an error in the determination in the process Because there is, determine the final cooking rice capacity to medium amount or large amount again. On the other hand, if it is determined that the rice cooking capacity is large in the process, but if it is reconfirmed that the rice cooking capacity is low according to the calculated integrated power consumption, the final rice cooking capacity is reduced to medium or small. Re-determine. In this way, even if the rice cooking amount is erroneously determined in the process, the correct rice cooking capacity can be determined based on the accumulated power amount data for the heating coil 16 thereafter. In addition, because the rice cooking capacity can be correctly determined before boiling, the cooked rice can be boiled with a heating amount suitable for the cooking rice capacity, and the spillage caused by inappropriate heating amount or the paste of the cooked rice due to insufficient heating Insufficiency can be prevented.

  The rice cooking control means 95 waits in the state of boiling heating 2 until the detected temperature P2 of the lid temperature sensor 65 taken in from the display microcomputer 76 is the temperature immediately before boiling, preferably 95 ° C (80-100 ° C), When this temperature is reached, the next boiling heating 3 is started. In the boiling heating 2 and the boiling heating 3, the solenoid 58 is turned off, the plunger 60 is held in the advanced position, and the pressure adjusting ball 45 is retracted from the opening 43. As a result, the lid 5 is not sealed and is in an open state in which the inside and outside of the pan 11 are communicated, and the inside of the pan 11 is maintained at substantially atmospheric pressure.

  In the boiling heating 3, a predetermined constant heating of, for example, 500 to 1100 W is applied to the pan 11 so that stable boiling detection can be performed. Thus, if the rate of temperature rise of the detected temperature P2 of the lid temperature sensor 65 slows below the predetermined temperature (1 to 5 ° C.) within a predetermined time (for example, 30 to 150 seconds), that is, the temperature gradient of the detected temperature P2 is sufficiently small. When it becomes, the boiling in the pan 11 is detected, and the rice cooking control means 95 ends the boiling heating process and shifts to the next boiling continuing process. The detected temperature P1 of the pan temperature sensor 21 and the detected temperature P2 of the lid temperature sensor 65 at the time when the boiling detection operation is finished are stored in a RAM (not shown) constituting the storage unit. The detected temperature P2 of the lid temperature sensor 65 at this time is a boiling temperature at atmospheric pressure obtained in an open state without sealing the lid 5 and is stored as a reference temperature PT (reference symbol PT in FIG. 3). reference).

  When the process of boiling heating 3 is completed, the process shifts to boiling continuation, and the rice cooking control means 95 continuously turns on the solenoid 58, which is the pressure adjusting means, and rolls the pressure adjusting ball 45 to the opening 43 by its own weight. Then, the sealing degree of the lid 5 is increased, and the heating coil 16 is heated to the pan 11 until the detection temperature P2 of the lid temperature sensor 65 reaches a preset first temperature. The important point here is that the first temperature is not an absolute temperature but is set to a relative temperature with respect to the reference temperature PT, such as a temperature higher by + 3 ° C. than the reference temperature PT. The reason will be described next.

  It is known that the boiling point (boiling temperature) and the pressure have a correlation as shown in FIG. For example, the boiling temperature at 1 atm (atm) is 100 ° C., and the boiling temperature at 1.1 atm is about 103 ° C. That is, if the reference temperature is 100 ° C. and the detected temperature P2 of the lid temperature sensor 65 is 3 ° C. higher than that, it can be determined that the pressure in the pan 11 is 1.1 atm.

  However, the lid temperature sensor 65 composed of a negative characteristic thermistor has a certain amount of variation in its resistance in manufacturing. For example, the detection temperature P2 of the lid temperature sensor 65 is the same, with 100 ° C. being the absolute boiling temperature at 1 atm. When the absolute temperature of 103 ° C. is detected, the pressure in the pan 11 is, for example, 1.05 atm or 1.2 atm, and the pressure in the pan 11 cannot be accurately detected. Therefore, as in the present embodiment, if the detection temperature P2 of the lid temperature sensor 65 at the time when it is determined to boil is set as the reference temperature PT, the reference temperature PT is obtained in accordance with the detection characteristics of the individual lid temperature sensors 65. Since it is temperature, the pressure of the pan 11 can be detected more accurately.

  Thereafter, when the detected temperature P2 of the lid temperature sensor 65 reaches the first temperature, the rice cooking control means 95 heats more than before until the detected temperature P2 reaches a second temperature lower than the first temperature. In order to reduce the amount of heating to the pan 11 by the coil 16 and continue heating, the solenoid 58 is periodically turned on and off in order to reduce the sealing degree of the lid 5. In this case, the pressure drop in the pan 11 becomes steeper as the amount of heating to the pan 11 decreases and as the off time of the solenoid 58 becomes longer than the on time. The second temperature is set to a temperature that is 1 ° C. higher than the reference temperature PT (a temperature that is two degrees lower than the first temperature), for example, when a white rice normal course is selected. When the detected temperature P2 of the lid temperature sensor 65 is lowered to the second temperature, the heating of the heating coil 16 to the pan 11 is increased and the solenoid 58 is continuously operated until the temperature rises again to the first temperature. Thus, the lid 5 is increased in the sealing state. Thereafter, while boiling continues, each time the detected temperature P2 of the lid temperature sensor 65 reaches the first temperature or the second temperature, the above operation is repeated, whereby the pressure in the pan 11 is shown in FIG. Fluctuate as follows.

  Here, when a menu that is desirable to be cooked in a state where the inside of the pan 11 is pressurized is selected, the sealing degree of the lid 5 is kept high. If a menu that should be cooked without selection is selected, heating to the pan 11 is reduced while lowering the sealing degree of the lid 5. That is, according to the menu selected by the course switch 30c or the cooking switch 30d, the cooking timing of the lid 5 leading to the pan 11 can be varied by changing the power interruption timing of the solenoid 58, so that the rice cooking control means 95 is changed. Is preferably configured. The first temperature and the second temperature are also preferably set according to the selected menu.

  For example, when the brown rice course which cooks brown rice as a to-be-cooked item is selected, the second temperature is set to a temperature higher than the normal white rice course, and cooking is performed in a state where the inside of the pan 11 is pressurized to some extent. Also, in the soft rice course that cooks soft and sticky rice even with the same white rice, while setting the second temperature to a slightly higher temperature than the normal white rice course, The second temperature is set to a temperature slightly lower than the white rice normal course. Thus, the first temperature, the second temperature, the degree of sealing of the lid 5 and the amount of heating to the pan 11 may be set in accordance with the food to be cooked and the finished feeling. In addition, stewed dishes such as stew are suitable for the selected cooking menu, such as setting the first temperature higher and setting the second temperature lower, so that the food will taste better. Set to temperature. At that time, the second temperature may be lower than the reference temperature PT. For cooking in which pressure is not applied, the first temperature and the second temperature are set lower than the reference temperature PT.

  Further, according to the rice cooking capacity (cooking amount) in the pan 11 determined by the capacity determining means 97, the first temperature, the second temperature, the sealing degree of the lid 5 and the heating amount to the pan 11 are individually set. It is good also as a structure set to. For example, when it is determined that the rice cooking capacity is large, the degree of sealing of the lid 5 is increased or the first temperature is set high so that the entire object to be cooked can be heated uniformly. Conversely, if it is determined that the rice cooking capacity is small, the sealing degree of the lid 5 may be lowered or the first temperature may be set low.

  If the detected temperature P2 of the lid temperature sensor 65 reaches the third temperature higher than the first temperature during cooking including the continuation of boiling, all heating to the pan 11 is stopped for safety. This third temperature is set slightly higher than the temperature detected by the lid temperature sensor 65 when both the opening 43 and the hole 49, which are vapor discharge holes, remain closed. The reason for this is that if the third temperature is set too high, heating to the pan 11 will continue indefinitely in a state where the pressurizing mechanism 47 and the safety valve 53 are not operating correctly.

  When a certain amount of time elapses while boiling continues, the water in the pan 11 evaporates and the temperature gradually rises. In particular, in cooking, since the temperature of the bottom of the pan 11 rises rapidly, the detected temperature P1 is a predetermined temperature (+2 to 10 ° C.) with respect to the detected temperature P1 of the pan temperature sensor 21 when boiling is detected. If it rises above, the rice cooking control means 95 will consider that the inside of the pan 11 is in a cooked (dry-up) state, and will move to the next uneven process. In the uneven process, the pan is turned off while turning off the heating coil 16 so that the detection temperature P1 of the pan temperature sensor 21 maintains a predetermined temperature (for example, 95 to 110 ° C.) for a predetermined time (for example, 6 to 16 minutes). Heat 11. When the unevenness process for a predetermined time is thus completed, the process proceeds to a heat insulation process by the heat insulation control means 96 instead of the rice cooking control means 95.

  In the heat insulation process, the bottom and side lower portions of the pan 11 are heated by the heating coil 16, and the inner lid 35 is heated slightly higher than the temperature of the rice in the pan 11 by the lid heater 68. Heating is performed by the heater 26, and the temperature is controlled so that the rice in the pan 11 is not dried and a large amount of dew does not adhere to the side surface of the pan 11. The temperature of the rice is maintained at 70 to 76 ° C. except for reheating.

  In addition, the sealing degree of the lid 5 in each process from the above-mentioned unevenness to the heat retention is changed according to the selected cooking course, but if the predetermined time before the end of unevenness, which is the substantial end of cooking, comes to the solenoid 58 is turned off to lower the sealing degree of the lid 5 and the pressure is reduced to the extent that it does not interfere with the opening of the lid 5 at the end of cooking.

  As described above, in this embodiment, the pan 11, the lid 5 as a lid for closing the opening of the pan 11, the solenoid 58 as an adjusting means for adjusting the sealing degree of the lid 5, and the pan 11 are provided. A heating coil 16 as a heating means for heating, a lid temperature sensor 65 as a temperature detection means for detecting the temperature of the lid 5, and a heating control means 71 as a control means for controlling the heating coil 16 and the solenoid 58, respectively. The heating control means 71 changes so that the detection temperature P2 of the lid temperature sensor 65 rises below a predetermined temperature within a predetermined time in a state where the sealing degree of the lid 5 is lowered by the on / off operation of the solenoid 58. When the temperature reaches the detected temperature P2 of the lid temperature sensor 65 at this time, the detected temperature P2 is set as the reference temperature PT. Thereafter, the solenoid 58 determines the temperature of the lid 5 according to the difference between the reference temperature PT and the detected temperature P2 of the lid temperature sensor 65. Configured to vary the degree of sealing To have.

  In this way, while the pan 11 is heated by the heating coil 16 during cooking, the detected temperature P2 from the lid temperature sensor 65 that detects the temperature in the lid 5 and thus the pan 11 is increased while the pressure of the pan 11 is lowered. When the rate changes to a predetermined value or less, it is determined that the inside of the pan 11 has almost boiled at that time, and the detected temperature P2 of the lid temperature sensor 65 at that time is set as the reference temperature PT.

  Here, since there is a correlation between the temperature and pressure when the inside of the pan 11 is in a boiling state, the pressure in the pan 11 can be grasped to some extent from the detected temperature P2 of the lid temperature sensor 65 without using the pressure sensor. Actually, since the individual lid temperature sensors 65 have variations in characteristics, even if the detected temperature P2 of the lid temperature sensor 65 at the time of boiling is the same, the pressure in the pan 11 is individually different. . Therefore, the pressure in the pan 11 is detected based on the relative temperature of how much the detected temperature P2 of the current lid temperature sensor 65 is different from the reference temperature PT when it is determined that the inside of the pan 11 is almost boiled. Then, even if the lid temperature sensor 65 has individual characteristic variations, the pressure in the pan 11 is more accurately detected, and the sealing degree of the lid 5 and thus the pressure in the pan 11 are adjusted to an appropriate state by the solenoid 58. Can be variably adjusted.

  Further, the heating control means 71 here increases the sealing degree of the lid 5 when the reference temperature PT is set, and the detected temperature P2 of the lid temperature sensor 65 reaches, for example, a first temperature higher than the reference temperature PT. The heating to the pan 11 by the heating coil 16 is decreased, and the heating to the pan 11 is increased when the detected temperature P2 of the lid temperature sensor 65 reaches a second temperature lower than the first temperature.

  In this case, if it is determined that the inside of the pan 11 is almost boiled, the detection temperature P2 of the lid temperature sensor 65 is set as the reference temperature PT, and then the detection temperature P2 of the lid temperature sensor 65 rises to the first temperature. If the heating to the pan 11 decreases and conversely decreases to a second temperature lower than the first temperature, the heating to the pan 11 increases. Thus, the pressure in the pan 11 at the time of cooking can be maintained within an appropriate range by adjusting the amount of heating to the pan 11 together with the degree of sealing of the lid 5 after detection of boiling.

  Further, the heating control means 71 here lowers the sealing degree of the lid 5 by the solenoid 58 when the detected temperature P2 of the lid temperature sensor 65 reaches the first temperature higher than the reference temperature PT, and the lid temperature sensor 65 When the detected temperature P2 reaches a second temperature lower than the first temperature, the solenoid 58 is controlled so that the sealing degree of the lid 5 is increased by the solenoid 58.

  In this case, if it is determined that the inside of the pan 11 is almost boiled, the detection temperature P2 of the lid temperature sensor 65 is set as the reference temperature PT, and then the detection temperature P2 of the lid temperature sensor 65 rises to the first temperature. Then, the solenoid 58 is controlled to lower the sealing degree of the lid 5, and conversely, when the temperature is lowered to a second temperature lower than the first temperature, the sealing degree of the lid 5 is increased. Thus, after the boiling is detected, the degree of sealing of the lid 5 is adjusted, and in some cases, the amount of heating to the pan is also adjusted, so that the pressure in the pan 11 during cooking is within an appropriate range. Can be maintained.

  In the present embodiment, a course switch 30c or cooking switch 30d as selection means for selecting a cooking course, and a capacity determination means 97 as estimation means for estimating the amount of cooking are provided, and the selected cooking course or estimated cooking amount Accordingly, the heating control means 71 is configured to change one or both of the first temperature and the second temperature.

  If it carries out like this, according to the selected cooking course or the estimated cooking amount, either the 1st temperature or the 2nd temperature used as the changing point which adjusts the sealing degree of the cover body 5 or the heating amount to the pan 11 will be shown. Since one or both of them can be changed, it is possible to perform optimum pressure cooking according to a desired cooking course and cooking amount.

  Further, according to the selected cooking course or the estimated cooking amount, the sealing degree of the lid 5 until the detection temperature P2 of the lid temperature sensor 65 reaches the first temperature and the detection temperature P2 of the lid temperature sensor 65 are The heating control means 71 may be configured to change either one or both of the sealing degrees of the lid 5 until reaching the second temperature.

  In this way, according to the selected cooking course or the estimated amount of cooking, until the detected temperature P2 of the lid temperature sensor 65 reaches the first temperature and until the second temperature is reached. Since either one or both of the sealing degree of the lid 5 can be changed, optimum pressure cooking according to a desired cooking course and cooking amount can be performed.

  Further, the heating control means 71 in the present embodiment is configured to stop the heating to the pan 11 when the detected temperature P2 of the lid temperature sensor 65 reaches a third temperature that is higher than the first temperature. Yes.

  In this case, when the detected temperature P2 of the lid temperature sensor 65 rises to a third temperature higher than the first temperature, which is not normal, heating to the pan 11 is stopped. By doing so, it is possible to reliably prevent the inside of the pan 11 from rising to an abnormal pressure.

  Further, the load driving microcomputer 77 constituting the heating control means 71 of this embodiment is composed of a digital signal processor. In this way, various processes in the heating control means 71 are executed at high speed by the digital signal processor, so that the pressure control in the pan 11 can be finely performed.

  In addition, this invention is not limited to said each Example, A various deformation | transformation implementation is possible. For example, the numbers of time and temperature in the examples are merely examples, and any of them can be changed as appropriate. Moreover, although the rice cooker was mentioned as an example and demonstrated in the present Example as a cooking device, it cannot be overemphasized that it can apply also to other things.

It is sectional drawing of the rice cooker in one preferable Example of this invention. It is a block diagram which shows an electrical structure same as the above. It is a graph which shows the temperature change of the pan temperature sensor and lid temperature sensor at the time of rice cooking, the heating amount of a heating coil, the pressure in a pan, and the state of a solenoid. It is a graph which shows the change of the rice temperature at the time of a heating, and a heating amount same as the above. It is a graph which shows the relationship between a boiling point and a pressure same as the above.

Explanation of symbols

5 Lid (lid)
11 Pot
16 Heating coil (heating means)
30c Course switch (selection method)
30d Cooking switch (selection means)
58 Solenoid (adjustment means)
65 Lid temperature sensor (temperature detection means)
71 Heating control means (control means)
97 Capacity judging means (estimating means)

Claims (7)

Pan, lid for closing opening, adjusting means for adjusting sealing degree, heating means for heating, temperature detecting means for detecting temperature of said lid, control means for controlling said heating means and said adjusting means When the detected temperature of the temperature detecting means changes by a predetermined temperature within a predetermined time with the sealing degree lowered, the control means sets the detected temperature of the temperature detecting means as a reference temperature, and the reference A cooking device characterized in that the sealing degree is varied in accordance with a difference between a temperature and a temperature detected by the temperature detecting means. The control means increases the sealing degree when the reference temperature is set, decreases the heating when the temperature detected by the temperature detecting means reaches the first temperature, and increases the heating when the temperature reaches the second temperature. The cooking device according to claim 1, wherein the cooking device is provided. The control means controls the adjusting means so that the degree of sealing is lowered when the temperature detected by the temperature detecting means reaches the first temperature, and the degree of sealing is raised when the temperature reaches the second temperature. The cooking device according to claim 1 or 2, characterized in that A selection means for selecting a cooking course; and an estimation means for estimating the amount of cooking, wherein the control means is configured to select the first temperature or the second temperature, or according to the selected cooking course or amount of cooking, or The cooker according to claim 2 or 3, wherein the first temperature and the second temperature are changed. Selection means for selecting a cooking course, and estimation means for estimating the amount of cooking, the control means according to the selected cooking course or amount of cooking, the degree of sealing until reaching the first temperature, Alternatively, the degree of sealing until the second temperature is reached, or the degree of sealing until the first temperature is reached and the degree of sealing until the second temperature is reached are changed. The cooker as described in any one of -4. The cooker according to any one of claims 2 to 5, wherein the controller is configured to reduce or stop heating when the temperature detected by the temperature detector reaches a third temperature. . The cooker according to any one of claims 1 to 6, wherein the control means is constituted by a digital signal processor.

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