Rice cooker

Abstract

To provide a rice cooker that can suitably detect that a lid body has a temperature abnormality.SOLUTION: A rice cooker 1 according to the present invention comprises: a pan 5 for housing rice to be cooked; a lid body 3 for openably / closably covering an opening part of a body 2 for housing the pan 5; an inner lid 39 provided in the lid body 3, and for covering an opening part of the pan 5 when the lid body 3 is closed; and a chip sensor 28 provided inside the lid body 3, and for detecting the temperature of the inner lid 39 in a noncontact manner.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a rice cooker capable of detecting abnormal temperatures in a lid that covers an opening of a pot that contains food to be cooked. [Background technology]

[0002] There have been many rice cookers of this type in the past, and the applicant of the present application has also proposed a rice cooker equipped with a thermistor-type lid sensor that detects the temperature of the inner lid in, for example, Patent Document 1. During cooking or keeping rice warm, the lid heater that heats the inner lid is controlled based on the temperature detected by the lid sensor, thereby controlling the temperature of the heat sink and, by extension, the inner lid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-295493 A Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technologies including Patent Document 1, the inner lid is attached to the lid body so as to be easily removable, and this makes it easy to clean the inner lid and keep it clean. However, since the lid sensor that detects the temperature of the inner lid detects the temperature of the inner lid by coming into contact with the inner lid, if the inner lid is removed, the lid sensor cannot detect the temperature of the inner lid, and therefore, even if there is a temperature abnormality in the lid body at that time, it cannot be detected.

[0005] 10 shows a front view of a conventional rice cooker 100 with the lid body 101 open and the inner lid removed. In a conventional rice cooker 1, if the drive circuit for the lid heater that heats the inner lid shorts out for some reason, the lid heater will be kept ON, and there is a risk that the heat sink 103 on which the lid heater is installed and the outer lid cover 102 will become hot. If a contact-type lid sensor 104 such as a thermistor that comes into contact with the inner lid to detect the temperature of the inner lid detects an abnormality at this time, the user is notified of the temperature abnormality by, for example, a display such as an LCD or LED or an alarm such as a buzzer.

[0006] However, because the temperature of the inner lid was detected by the contact-type lid sensor 104, it was not possible to detect a temperature abnormality, for example, when the inner lid was removed from the lid body 101 for cleaning. In such a case, the user could not be notified even if the heat sink 103 or outer lid cover 102 became too hot, and there was a risk that the user would come into contact with the heat sink 103 or outer lid cover 102 that had become too hot.

[0007] An object of the present invention is to provide a rice cooker that can suitably detect when the temperature of the lid has become abnormal. [Means for solving the problem]

[0008] The present invention relates to a pot for containing food to be cooked, a lid for freely opening and closing the opening of the main body for containing the pot, an inner lid provided on the lid and for covering the opening of the pot when the lid is closed, and a cooking pot for cooking rice. Before Inner lid and Non-contact Established A lid temperature detection means; A display unit that displays various information; Equipped with The display unit is provided on a substrate disposed inside the lid body, and the lid temperature detection means is provided on the substrate, and the lid temperature detection means detects the temperature of the inner lid by detecting the ambient temperature of the substrate. It is characterized by the above. Effect of the Invention

[0009] According to the present invention, regardless of whether an inner lid is present or not, the temperature of the part forming the lower part of the lid body can be detected, and it can be detected when the part forming the lower part of the lid body has become too hot. [Brief description of the drawings]

[0010] [Figure 1] 1 is an external perspective view of a rice cooker showing one embodiment of the present invention; [Diagram 2] FIG. [Diagram 3] FIG. 11 is a perspective view of the inner lid assembly unit as viewed from above. [Figure 4] FIG. 11 is a perspective view of the inner lid assembly unit as viewed from the bottom side. [Diagram 5] FIG. 2 is a front view showing the rice cooker with the lid open. [Figure 6] FIG. 13 is a block diagram showing the electrical configuration of the first embodiment. [Figure 7] 11 is a graph showing the correlation between the temperature detected by the chip sensor and the temperature of the inner lid. [Figure 8] FIG. 13 is an explanatory diagram of the rice cooker with the lid open. [Figure 9] Same as above, (A) is a front view showing the rice cooker with the lid open and the inner lid assembly unit removed, (B) is a top view of the rice cooker and a plan view seen from the back of the control PC board. [Figure 10] FIG. 11 is a front view showing a conventional rice cooker with the lid body open and the inner lid removed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Each embodiment of the rice cooker of the present invention will be described with reference to the attached drawings. Note that the embodiments described below do not limit the contents of the present invention described in the claims. Furthermore, all of the configurations described below are not necessarily essential requirements of the present invention. The directions indicated by the arrows (up, down, front, rear, right, left) in FIG. 1 will be described as the upper side, lower side, front side, rear side, right side, and left side of the rice cooker, respectively. Furthermore, common symbols will be used for common parts throughout these drawings.

[0012] 1 to 9 show an embodiment of the present invention. The overall configuration of the rice cooker in this embodiment will be described with reference to Figs. 1 and 2. 1 is a rice cooker, and is generally rectangular in shape with the front and rear, left and right sides facing each other when viewed from above, and the rice cooker 1 has an open top. The entirety is made up of a main body 2 of the rice cooker 1 and a lid 3 that can be opened and closed to cover the top opening of the main body 2. The main body 2 has a pot housing section 4 that has an open top, and when the lid 3 is opened, a bottomed pot 5 serving as a container for holding water or rice to be cooked is detachably housed in the pot housing section 4. The outer shell of the main body 2 is formed by an upper frame 6 that constitutes the upper and side parts, an outer frame 7 that constitutes a part of the upper part, and a bottom plate 8 that covers the lower part of the upper frame 6. In this case, the upper frame 6 and the bottom plate 8 are formed of a synthetic resin such as PP, and the outer frame 7 is formed of a metal member such as stainless steel. Pot storage section 4 is formed integrally with upper frame 6, and the bottom is configured by combining with a bowl-shaped inner frame 9 made of resin such as PET, etc., so that the whole is formed into a cylindrical shape with a bottom.

[0013] Pot 5 is mainly made of aluminum, which has good thermal conductivity, and a heating element made of a magnetic metal plate such as ferritic stainless steel is joined to the outer surface of the main material from the lower side to the bottom. In addition, a heating coil 11 is provided on the outer surface of inner frame 9, which faces the bottom surface from the lower side of pot 5, as heating means for electromagnetic induction heating of the heating element of pot 5. A thermistor-type pot sensor 15 is disposed in the center of the bottom of inner frame 9 as pot temperature detection means so as to come into elastic contact with the outer bottom surface of pot 5. Pot sensor 15 in this embodiment is configured to detect the temperature of pot 5 and mainly control the heating temperature of the bottom of pot 5 by heating coil 11.

[0014] A cord heater 16 (see FIG. 6) is provided at the top end of pot housing 4, and cord heater 16 is covered with metal plate 12 made of a material with good thermal conductivity such as aluminum. Metal plate 12 is provided at a position facing gap 13 between main body 2 and lid 3, which serves as a heat dissipation section, and cord heater 16 and metal plate 12 form a flange heater as a heat generating means. The bottom surface of flange 14, which extends from the top end of pot 5 all the way around the outside, is placed on the top surface of metal plate 12, and pot 5 is housed in pot housing 4 in a suspended state. Therefore, in this state, there is almost no gap between pot 5 and the top end of pot housing 4. However, metal plate 12 has a partial gap 13 in a plan view so that the handle formed on flange 14 of pot 5 is not in contact with metal plate 12. This allows steam to be discharged from gap 13 when rice is cooked with water attached to the outer surface of pot 5. Furthermore, flange portion 14 of pot 5 is formed with an outer shape that is equal to or larger than cord heater 16 so as to cover cord heater 16, which is the heat generating portion.

[0015] During cooking and keeping warm, the pot 5 is heated by the heating means, while during keeping warm, the heating coil 11 is heated and adjusted according to the temperature detected by the pot sensor 15 to keep the pot 5 at a constant temperature. After cooking, the cord heater 16, which serves as the heating means, is made to generate heat until the temperature of the rice in the pot 5 drops from the freshly cooked temperature of approximately 100°C to the keeping warm temperature of approximately 73°C, and even when the temperature is kept stable at approximately 73°C, the cord heater 16 is made to generate heat, radiating heat from the metal plate portion 12 to the gap 13 between the main body 2 and the lid 3, suppressing cooling caused by the intrusion of outside air from the gap 13 and heating the pot 5. Furthermore, during keeping warm, the cord heater 16 is made to generate heat to heat the pot 5 during the period when hot reheating is being performed to reheat the rice in the pot 5, and prevents moisture generated by reheating from condensing on the upper inner surface of the pot 5.

[0016] A lid-opening button 17 is provided in an exposed state on the front upper surface of the lid 3, and when this lid-opening button 17 is pressed, the engagement between the main body 2 and the lid 3 is released, and the lid 3 is automatically opened around a hinge shaft 19 by a hinge spring 18 provided at the upper rear of the main body 2. A steam vent unit 21 is detachably attached to the rear upper surface of the lid 3, forming an exhaust path for exhausting steam generated from the food being cooked in the pot 5 to the outside of the rice cooker 1.

[0017] In addition to the lid opening button 15 and steam vent unit 21, an operation panel 22 for displaying button names and the like is disposed on the top surface of the lid 3, which serves as a display and operation unit for the rice cooker 1. This operation panel 22 is provided with an LCD 23 that displays the time and the selected rice cooking course as a display section that displays various information, and an LED 24 (see FIG. 6) that displays the current process, and is provided with a switch 25 as an operation section for starting and stopping rice cooking, selecting a rice cooking course, etc. The LCD 23, LED 24, and switch 25 are provided on a control PC (Printed Circuit) board 26 disposed inside the lid 3. This control PC board 26 is equipped with a display / operation control means 27 (see FIG. 6) which is a control means for the operation panel 22, a chip sensor 28 as a cover temperature detection means, and a buzzer 30 as an alarm means, and also has a patterned conductive circuit portion. By mounting a control IC 61 related to operation and display on this control PC board 26, the display / operation control means 27 linked to a heating control means 31 described later is formed. In addition, since the chip sensor 28 is disposed on the control PC board 26 which is a substrate on which the LCD 23, the LED 24, and the display / operation control means 27 are disposed, the number of parts can be reduced, and since wiring can be performed within the control PC board 26, the circuit configuration can be simplified and costs can be reduced. The operation panel 29 also prevents dust and water from adhering to the electronic components, the LCD 23, the LED 24, the switch 25, and the control PC board 26.

[0018] The lid body 3 is provided with a lid heating means 29 constituted by, for example, a cord heater as a lid heater, and this lid heating means 29 is configured to mainly control the temperature of an inner lid 39, which will be described later.

[0019] Reference numeral 31 denotes a heating control means for controlling the temperature of the pot 5 and the inner lid 39 by detecting the temperature from the pot sensor 15 and the chip sensor 28 during cooking and keeping warm. The heating control means 31 receives detection signals from the pot sensor 15 and the lid temperature sensor 17, and adjusts the heating of the heating coil 11, the cord heater 16, and the lid heating means 29 as heating means. The heating control means 31 includes an element 32 for controlling the driving of the heating coil 11, which drives the heating coil 11 to heat the heating element of the pot 5 by electromagnetic induction. The element 32 has a usage condition temperature and must be operated at or below a certain temperature. Therefore, a radiator 33 made of a material with good thermal conductivity, such as aluminum, is attached to the element 32, and the element 32 is cooled by the wind from a cooling fan 34 as a cooling means, so that the element 32 is driven within the usage condition temperature. The cooling fan 34 is disposed below or to the side of the radiator 33 attached to the heating control means 31.

[0020] At the bottom or side of the rice cooker to be produced, a cooling fan 34 is installed to blow air that has been warmed by the radiator 33 and is then released to the outside. Hole The heating control means 31 is housed inside the main body 2, which is the inside of the product, but may be disposed at any position relative to the pot 5. Holes However, in recent years, there has been a demand for compact designs of products, and it is necessary to install the heating control means 31, the cooling fan 34, and the air outlet. Hole and It is preferable that they are arranged in approximately opposite directions with the pot 5 in between.

[0021] The lid body 3 is composed of an outer lid 36, which is an outer shell part, and an outer lid cover 37 that forms the lower part of the outer lid 36. The outer lid cover 37 is provided with a metal heat sink 38 made of stainless steel or aluminum that has been anodized (alumite), and the heat sink 38 is provided with a lid heating means 29. As shown in FIG. 2, an inner lid 39 made of metal made of stainless steel or aluminum that has been anodized is provided below the heat sink 38. The outer periphery of the inner lid 39 that forms the lower surface of the lid body 3 is provided with a lid packing 41 as a sealing member that seals the gap between the pot 5 and the inner lid 39 when the lid body 3 is closed. The lid packing 41 is made of silicone rubber or fluororubber, and is configured to abut against the upper surface of the flange portion 14 of the pot 5 when the lid body 3 is closed. The inner lid 39 and the lid packing 41 are integrated with a packing base 42, and an inner lid assembly unit 43 mainly composed of these parts is detachably attached to the inner surface of the outer lid cover 37. Therefore, when the lid body 3 is closed to the main body 2 with the inner lid assembly unit 43 attached, the lid gasket 41 abuts against the upper surface of the flange portion 14, and the inner lid assembly unit 43 is configured to cover the upper opening of the pot 5 without any gaps.

[0022] Next, the configuration of the inner lid assembly unit 43, which essentially corresponds to the inner lid of this embodiment, will be described with reference to Figs. 3 to 5. The inner lid assembly unit 43 has a steam exhaust hole 45 and a pressure reduction hole 46, which are opened in the inner lid 39. The resin packing base 42, which is formed in a substantially annular shape, has a convex insertion part 47 that partially protrudes in the outer circumferential direction. With the lid body 3 open, the insertion part 47 is inserted into a recess 48 formed on the base end side near the hinge part 31 on the inner surface of the lid body 3, and the packing base 42 is fitted to the outer lid cover 37, so that the inner lid assembly unit 43 can be attached to a predetermined position on the inner surface side of the lid body 3, as shown in Fig. 5. Above the pressure reduction hole 46, a cylindrical pressure reduction packing 49 (see Fig. 9) protruding downward from the heat sink 38 is provided.

[0023] Next, the internal structure of lid body 3 will be further described with reference to Fig. 2. Lid body 3 is formed with steam exhaust path 51 that communicates with the inside of pot 5 and connects steam port unit 21 to pressure adjustment section 53 as a passage for discharging steam generated within pot 5 to the outside of the rice cooker. Pressure adjustment section 53 is provided with pressure adjustment valve 54 that opens and closes steam exhaust path 51 between the inside of pot 5 and steam port unit 21. Pressure adjustment valve 54 is, for example, a solenoid valve and can be driven vertically. When steam within pot 5 is to be discharged to the outside, pressure adjustment valve 54 is driven upward to open steam exhaust path 51, and when the pressure inside pot 5 is reduced, pressure adjustment valve 54 is driven downward to close steam exhaust path 51.

[0024] 55 is a pressure reducing pump for lowering the pressure inside the pot 5 below normal atmospheric pressure when the lid 3 is closed on the main body 2. The pressure reducing pump 55 reduces the internal pressure of the sealed pot 5 through a path (not shown) that connects the pressure reducing pump 55 to the pressure reducing hole 46 when the pot 5 is housed in the pot housing 4 and the lid 3 is closed and the pressure adjusting valve 54 is driven downward to close the steam exhaust path 51. When the pressure inside the pot 5 drops below atmospheric pressure by a certain value, the pressure reducing pump 55 operates to keep the inside of the pot 5 in a reduced pressure state. When the pressure inside the pot 5 is to be returned from the reduced pressure state to the same pressure as the outside air, the operation of the pressure reducing pump 55 is stopped and the pressure adjusting valve 54 is driven upward to open the steam exhaust path 51. In other words, the pressure reducing pump 55 and the path that connects the pressure reducing pump 55 to the pressure reducing hole 46 act as a pressure reducing means for lowering the pressure inside the pot 5 below normal atmospheric pressure, and also serve as a pressure returning means for returning the pressure inside the pot 5 from the reduced pressure state to the same pressure as the outside air. A valve capable of opening and closing the path that communicates between the decompression pump 55 and the decompression hole 46 may be provided in the path.

[0025] Next, the control system of the heating control means 31 and the display / operation control means 27 will be described with reference to Fig. 6. In the figure, the heating control means 31 provided in the main body 2 includes an element 32 as a control IC constituting a microcomputer, a memory means 57, a timing means (not shown), etc., and receives a temperature detection signal from the pot sensor 15, a control signal from the display / operation control means 27, and a temperature detection signal from the chip sensor 28 via the display / operation control means 27, to control the heating coil 11 that heats the pot 5 during rice cooking and warming, the lid heating means 29 that heats the inner lid 39, and the cord heater 16 that heats the flange portion 14 of the pot 5, as well as controlling the operation of the pressure adjusting valve 54 and the pressure reducing pump 55 mentioned above. In particular, heating control means 31 controls the temperature of the bottom of pot 5 mainly by controlling heating coil 11 based on the temperature detected by pot sensor 15, controls the temperature of flange portion 14 of pot 5 by controlling cord heater 16, and controls the temperature of inner lid 39 mainly by controlling lid heating means 29 based on the temperature detected by tip sensor 28. Heating coil 15, lid heating means 29, and cord heater 16 correspond to heating means that heat the food to be cooked placed in pot 5.

[0026] The heating control means 31 has rice cooking control means 58 and warming control means 59 in element 32 as functions in the control sequence of the program read from storage means 57. Upon receiving an instruction to start cooking rice from, for example, the rice cooking key of switch 25 as an operating unit, rice cooking control means 58 sequentially executes each of the following processes: a soaking cooking process to promote the absorption of water by the rice put into pot 5, a boiling heating process to raise the temperature of the food to boiling in a short time, a boiling continuing process to keep the food boiling, and a steaming process to keep the rice at a high temperature but not so hot that it burns, thereby cooking and heating the food in pot 5 at a desired pressure. Also, warming control means 59 controls the warming process to keep the rice in pot 5 at a predetermined warming temperature.

[0027] On the other hand, the display / operation control means 27 includes a control IC 61, a storage means 62, a timer means (not shown) and the like which constitute a microcomputer, and receives an operation signal from the switch 25 and a control signal from the heating control means 31 to control the display operation of the LCD 23 and the LED 24 as a display unit, controls the operation of the buzzer 30 as an informing means, and transmits a control signal to the heating control means 31. As functions of the control sequence of the program stored in the storage means 62, the display / operation control means 27 includes an operation unit control means 63 which generates various control signals based on an operation signal from the switch 25, a display operation control means 64 which controls the display operation of the LCD 23 and the LED 24, and a condition setting means 65 which cooperates with the operation unit control means 63 and the display operation control means 64 to select and set conditions that can be selected by the switch 25, for example, to select and set a desired cooking course or rice cooking course from a plurality of cooking courses or rice cooking courses.

[0028] Next, the operation of the rice cooker 1 configured as above in the rice cooking process will be described. First, rice and water are placed in the pot 5 as the food to be cooked, and then the pot is placed in the pot housing 4 of the main body 2, and the lid 3 is closed. Around the same time, when the power plug (not shown) of the rice cooker 1 is inserted into an outlet to turn on the power, the rice cooker 1 goes into the initial off (standby) state in which no rice is being cooked or kept warm. Here, each time the switch 25 is operated, the operation signal is received by the operation unit control means 63, and the setting of the rice cooking course is changed by the condition setting means 65. The changed setting is displayed on the LCD 23 by the display operation control means 64 each time, and the user can visually confirm this.

[0029] Then, when the rice cooking key of switch 25, for example, is operated after the rice cooking course is set, the operation signal is received by operation unit control means 63, and condition setting means 65 stores the setting currently displayed on LCD 23 in memory means 62 as the setting for the current rice cooking course, and sends information on the heating pattern corresponding to the set rice cooking course to heating control means 31. In response to this, heating control means 31 performs each of the rice cooking operations of the soaking cooking process, boiling heating process, continued boiling process, and steaming process for the food in pot 5 according to the heating pattern of the set rice cooking course, using rice cooking control means 58 incorporated in element 32.

[0030] More specifically, when the heating control means 31 receives information sent from the display / operation control means 27, the process proceeds to the soaking process, and the rice cooking control means 58 controls the operation of the pressure regulating valve 54 and the pressure reducing pump 55 so that the pressure inside the pot 5 is reduced below atmospheric pressure during the soaking process. Specifically, when the soaking process starts, the rice cooking control means 58 closes the steam exhaust path 51 with the pressure regulating valve 54. In this state, the rice cooking control means 58 operates the pressure reducing pump 55 continuously, and performs a vacuum pull to remove the air inside the sealed pot 5 with the pressure reducing pump 55. After that, the rice cooking control means 58 controls the pressure reducing pump 55 so that the pressure inside the pot 5 is maintained at a reduced pressure below a certain value. In this way, the inside of the pot 5 is kept in a reduced pressure state throughout the entire period of the soaking process.

[0031] The rice cooking control means 58 controls heating of the pot 5 by controlling the power on and off of the heating coil 11 based on the temperature detection of the bottom of the pot 5 by the pot sensor 15, promoting the water absorption of the rice and at the same time calculating the amount of rice to be cooked in the pot 5 from the time and amount of heat required to reach a predetermined temperature. After the predetermined time has elapsed and the soaking process is completed, the process moves to the next boiling and heating process.

[0032] When the process moves to the boiling heating process, the rice cooking control means 58 controls the heating coil 11 to be continuously energized until the boiling of the food is detected, thereby heating the food in the pot 5 more strongly than in the soaking cooking process, and raising the temperature of the food to boiling in a short time. The rice cooking control means 58 also controls the pressure reducing pump 55 to stop operating, while controlling the pressure adjusting valve 54 to keep the steam exhaust path 51 closed, so that the inside of the pot 5 is maintained in a reduced pressure state lower than atmospheric pressure after the soaking cooking process. Therefore, even after the process moves from the soaking cooking process to the boiling heating process, the pressure inside the pot 5 gradually increases due to heating of the pot 5 and slow leakage, but the reduced pressure state can be maintained for a while without operating the pressure reducing pump 55. If a valve capable of opening and closing the path is provided in the path connecting the pressure reducing pump 55 and the pressure reducing hole 46, the valve may be closed to close the path. In this way, the food inside pot 5 is kept in a reduced pressure state even during the heating process after the soaking process, so that the water boils at a temperature of 100°C or less during the heating process. Therefore, by boiling the food under reduced pressure at 60°C to 100°C, which is the gelatinization temperature of rice, the boiling bubbles make the rice dance, eliminating uneven heating, and the reduced pressure state of the food allows the rice to absorb water all the way to the core in a short time.

[0033] Next, the rice cooking control means 58 takes in a temperature detection signal from the pot sensor 15, and when the detected temperature at the bottom of the pot 5 reaches the predetermined temperature of 100°C, it determines that the food inside the pot 5 has boiled under reduced pressure, and controls the pressure regulating valve 54 to open without operating the pressure reducing pump 55. As a result, the steam exhaust path 51 is in an open state that communicates between the inside and outside of the pot 5 without sealing it, and the inside of the pot 5 immediately returns to normal pressure, the same as the outside air. In this way, when the rice cooking control means 58 determines that the food inside the pot 5 has boiled under reduced pressure during the boiling heating process, it controls the operation of the pressure regulating valve 54 to instantly switch the inside of the pot 5 from a reduced pressure state to atmospheric pressure, and opens the steam exhaust path 51.

[0034] Then, the rice cooking control means 58 detects that the temperature of the pot 5 has reached a predetermined temperature or higher, for example 90°C or higher, based on a temperature detection signal from the pot sensor 15, and when it additionally detects that the temperature of the inner lid has reached a predetermined temperature or higher, for example 90°C or higher, based on a temperature detection signal from the chip sensor 28, it begins control of boiling detection to detect the boiling of the food being cooked.

[0035] The lid heating means 29 directly heats the heat sink 38, thereby heating the inner lid 39 which is in contact with the heat sink 38. Therefore, when the lid heating means 29 heats the heat sink 38, the heat inside the heat sink 38 moves into the outer lid cover 37, and then moves to the periphery of the control PC board 26. In the rice cooker 1 of this embodiment, the chip sensor 28 detects the atmospheric temperature of the control PC board 26, which is the temperature around the control PC board 26, and the rice cooking control means 58 estimates and detects the temperature of the inner lid 39.

[0036] FIG. 7 is a graph showing the correlation between the temperature detected by the chip sensor 28 and the temperature of the inner lid 39. The memory means 57 stores the graph of FIG. 7, and the rice cooking control means 58 calculates the temperature of the inner lid 39 using the graph of FIG. 7. For example, point a indicates the temperature detected by the chip sensor 28 when the temperature of the inner lid 39 is 90°C, and the temperature detected by the chip sensor 28 at this time is t1, i.e., approximately 37°C. Therefore, when the rice cooking control means 58 detects from the temperature detection signal from the chip sensor 28 that the temperature detected by the chip sensor 28 has reached t1 or higher, for example, 37°C or higher, the rice cooking control means 58 is configured to determine that the temperature of the inner lid 39 has reached 90°C or higher.

[0037] When the rice cooking control means 58 starts the control of boiling detection, it continues to control the heating coil 11 and the cord heater 16 to be continuously energized to strongly heat the food inside the pot 5, while calculating the slope of the detected temperature, which is the degree to which the detected temperature of the pot sensor 15 and the detected temperature of the chip sensor 28 rise in a predetermined time. Specifically, when the rice cooking control means 58 calculates that the rise in the temperature of the pot 5, which is the temperature of the bottom of the pot 5, from the detected temperature of the pot sensor 15 has become equal to or lower than a predetermined temperature rise rate, such as 3°C or less in 120 seconds, it determines that boiling due to a change in the temperature rise rate of the pot 5 has been detected. Also, when the rice cooking control means 58 calculates that the rise in the temperature of the inner lid 39 from the detected temperature of the chip sensor 28 has become equal to or lower than a predetermined temperature rise rate, such as 1°C or less in 60 seconds, it determines that boiling due to a change in the temperature rise rate of the inner lid 39 has been detected. When the rice cooking control means 58 detects boiling due to a change in the rate of temperature rise of the pot 5 and also detects boiling due to a change in the rate of temperature rise of the inner lid 39, it transitions to the next boiling continuation step.

[0038] When the process moves to the continuing boiling step, the rice cooking control means 58 controls the supply and disconnection of electricity to the heating coil 11 and the cord heater 16 so that the temperature of the pot 5 based on the temperature detected by the pot sensor 15 is maintained at a predetermined temperature, for example 98°C or higher, and also controls the continuous supply of electricity to the lid heating means 29 so that the temperature detected by the chip sensor 28 is maintained at a predetermined temperature, for example 45°C or higher at point b in Figure 7, i.e., the temperature of the inner lid 39 is maintained at 98°C or higher, thereby maintaining the boiling state of the cooked food.

[0039] When the water inside pot 5 runs out during the continuing boiling process and the rice cooking control means 58 calculates from the temperature detected by pot sensor 15 that the temperature rise at the bottom of pot 5 exceeds a predetermined temperature rise rate, such as 0.5°C or more in 10 seconds, it determines that it has detected a change in the rate of temperature rise of pot 5. Here, when the temperature detected by pot sensor 15 reaches the predetermined dry-up temperature, it detects that the food inside pot 5 is done, the continuing boiling process ends, and it moves to the next steaming process.

[0040] During the steaming process, the rice cooking control means 58 controls the temperature by turning on and off the lid heating means 29 according to the temperature detected by the chip sensor 28 to prevent dew from forming on the inner lid 39, and controls the temperature of the bottom of the pot 5 by turning on and off the heating coil 11 so that a high temperature is maintained so that the rice inside the pot 5 does not burn. When a predetermined time has passed and the steaming process is finished, the rice cooking process is completed, and the display / operation control means 27 receives a control signal from the heating control means 31 and controls the display of the LCD 23 and LED 24, and also controls the buzzer 30 to perform an announcing operation to notify the user that the rice cooking process is complete, and the process proceeds to a keep-warm process by the keep-warm control means 59.

[0041] FIG. 8 shows a state where the user's finger touches the inner lid 39 with the lid body 3 open. Burns (burns) depend on the temperature of the contacted object and the contact time. When the temperature of the contacted object is 120°C, a contact time of 5 seconds is required to cause a second-degree burn (see TED Y538C). Here, a second-degree burn is a burn in which a blister appears at the contacted part, and in severe cases, water may accumulate under the skin. If the blisters, which are the state where water accumulates under the skin, do not suppurate, it can heal without leaving a significant scar. Since a first-degree burn is a burn in which the skin is only reddened, a second-degree burn is explained here. Here, the contact time, which is the time from when a person feels "hot" to when they remove the part of their finger or other contacted object, is usually about 0.2 to 0.3 seconds, less than 1 second, and if the contacted object is less than 150°C, it usually does not result in a second-degree burn.

[0042] In the rice cooker 1 of the present invention, a triac is used in the drive circuit of the lid heating means 29, and this drive circuit controls the ON / OFF of the lid heating means 29 by receiving a control signal from the heating control means 31. If the triac of the drive circuit controlling the lid heating means 29 as the lid heater becomes defective due to initial failure or aging, or if there is a short circuit due to solder on the control PC board 26, or if other parts such as transistors used in the drive circuit fail due to static electricity, etc., the lid heating means 29 cannot be turned ON / OFF by the control signal from the heating control means 31, and the lid heating means 29 is kept ON, and the heat sink 38 on which the lid heating means 29 is provided and the inner lid 39 in contact with the heat sink 38 may become so hot that they may cause second-degree burns if they come into contact with each other. Therefore, in this embodiment, a chip sensor 28, which is a temperature detection means that does not come into contact with the inner lid 39, is provided inside the lid body 3, so that the temperature of the outer lid cover 37 that forms the lower part of the lid body 3 can be detected regardless of the presence or absence of the inner lid 39.

[0043] 9(A) and 9(B), as shown in Fig. 9(A), the rice cooker 1 of this embodiment does not have a lid sensor on the heat sink 38, and does not have a temperature sensor that directly detects the temperature of the inner lid 39. On the other hand, as shown in Fig. 9(B), in the rice cooker 1 of this embodiment, a chip sensor 28 is provided as a lid temperature detection means on the control PC board 26 on which the LCD 23, LED 24, and switch 25 are provided inside the lid body 3, and the heating control means 31 estimates the temperature of the inner lid 39 based on a detection signal from the chip sensor 28, thereby detecting the temperature of the inner lid 39 without contacting the inner lid 39.

[0044] Next, the operation of the rice cooker 1 configured as above will be described. When a temperature detection signal is received from the tip sensor 28 via the display / operation control means 27, the heating control means 31 calculates the temperature of the inner lid 39 by applying this information to the correlation graph of the temperature detected by the tip sensor 28 and the temperature of the inner lid 39 shown in Fig. 7, which is stored in the storage means 57. The heating control means 31 also has time and temperature thresholds, such as the temperature detected by the tip sensor 28 being 85°C or higher for 10 minutes or more, and the temperature value Th of this threshold is a value that is not reached during the normal rice cooking process or warming process.

[0045] Here, when the heating control means 31 receives a notification via the display / operation control means 27 that the temperature detected by the tip sensor 28 has reached or exceeded the threshold temperature of 85°C, the heating control means 31 uses the timing means to measure the time during which the temperature remains at or above the threshold temperature Th. As shown in Fig. 7, in the rice cooker 1 of this embodiment, the temperature detected by the tip sensor 28 rises to approximately 81.5°C during the normal rice cooking process and warming process, i.e., the temperature of the inner pot 39 rises to approximately 125°C. Therefore, in order to avoid the risk of false detection during normal use, the temperature threshold Th is set to 85°C, i.e., the temperature of the inner pot 39 is approximately 130°C, and a predetermined time is also set to determine whether the temperature remains at or above the temperature threshold Th for the predetermined time or longer.

[0046] Thereafter, when the heating control means 31 receives from the timer means that the time at or above the threshold temperature measured by the timer means has exceeded the threshold time, the heating control means 31 determines that the temperature of the inner pot 39 is abnormal and sends a control signal to the display / operation control means 27, which in turn controls the LCD 23 and LED 24 to display an error message indicating the temperature is abnormal, and also controls the buzzer 30 to sound an alarm to notify the user that the lid temperature is abnormal. Therefore, regardless of the presence or absence of the inner lid 39, the temperature of the outer lid cover 37 forming the lower part of the lid body 3 can be detected, and the user can be notified of the abnormality in the lid temperature by the display of the LCD 23 and LED 24 and the alarm operation of the buzzer 30, to call attention to the abnormality in the lid temperature.

[0047] In this embodiment, the temperature abnormality of the lid temperature of the inner pot 39 is detected by the temperature detected by the chip sensor 28, but the chip sensor 28 may be configured to detect temperature abnormalities inside the lid body 3 to which the inner pot 39 is attached, or may be configured to detect temperature abnormalities in the control PC board 26 on which the chip sensor 28 is provided. The correlation graph between the temperature detected by the chip sensor 28 and the temperature of the inner lid 39 in Fig. 7, as well as the time and temperature thresholds, are stored in the storage means 62 of the display / operation control means 27, and the display / operation control means 27 may measure the time for which the temperature is equal to or higher than the threshold temperature Th using a timing means, control the LCD 23 and LED 24 to display an error message, and control the buzzer 30 to sound an alarm to notify of the temperature abnormality.

[0048] As described above, the rice cooker 1 of this embodiment includes the pot 5 for containing the food to be cooked, the lid 3 for freely opening and closing and covering the opening of the main body 2 containing the pot 5, the inner lid 39 attached to the lid 3 for covering the opening of the pot 5 when the lid 3 is closed, and the chip sensor 28 attached inside the lid 3 as a lid temperature detection means for detecting the temperature of the inner lid 39 in a non-contact manner. Therefore, regardless of the presence or absence of the inner lid 39, it is possible to detect the temperature of the outer lid cover 37 which is the part forming the lower part of the lid 3. For example, even if the inner lid 39 is removed, it is possible to detect that the outer lid cover 37 or the heat sink 38 has become too hot, and it is possible to detect that the lid 3 has become abnormal in temperature.

[0049] In addition, the rice cooker 1 of this embodiment is further equipped with an LCD 23 and an LED 24 as a display unit that displays various information, and the LCD 23 and LED 24 are provided on a control PC board 26 serving as a substrate arranged inside the lid body 3, and a chip sensor 28 is provided on the control PC board 26. This reduces the number of components and allows wiring to be done within the control PC board 26, simplifying the circuit configuration and reducing costs.

[0050] In addition, in the rice cooker 1 of this embodiment, the chip sensor 28 is a chip element, so that it can be easily mounted on the control PC board 26 and costs can be reduced.

[0051] In addition, the rice cooker 1 of this embodiment is further configured to include a heating control means 31 as a judgment means for judging whether the temperature of the inner lid 39 is equal to or higher than a predetermined threshold temperature Th, making it possible to judge whether the temperature of the inner lid 39 is abnormal.

[0052] In addition, in the rice cooker 1 of this embodiment, the heating control means 31 measures the time that the temperature of the inner lid 39 is above the threshold temperature Th and determines whether it is above a predetermined time, thereby avoiding the risk of false detection during normal use.

[0053] In addition, the rice cooker 1 of this embodiment is further equipped with an LCD 23, an LED 24, and a buzzer 30 as notification means that alert when the heating control means 31 determines that the temperature has reached a predetermined temperature Th or exceeded a predetermined time, and the display of the LCD 23 and the LED 24 and the notification action of the buzzer 30 can alert the user to an abnormality in the lid temperature and draw their attention.

[0054] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. Furthermore, the numerical values ​​exemplified in the embodiment are merely examples, and may be modified as appropriate according to the specifications of the rice cooker. [Explanation of symbols]

[0055] 1. Rice cooker 2 Main unit 3 Lid 5. Pot 23 LCD (display unit, notification means) 24 LED (display section, notification means) 26 Control PC board (circuit board) 28 Chip sensor (lid temperature detection means) 29 Lid heating means 31 Heating control means (determination means) 36 Outer lid 37 Outer cover 38 Heat sink 39 Inner lid

Claims

1. A pot for containing food to be cooked; A lid that can open and close the opening of the main body that houses the pot; An inner lid is provided on the lid body and covers the opening of the pot when the lid body is closed; A lid temperature detection means is provided inside the lid body in a non-contact manner with the inner lid; A display unit that displays various information, the display unit is provided on a substrate disposed inside the lid, The lid temperature detection means is provided on the substrate, The rice cooker is characterized in that the lid temperature detection means detects the temperature of the inner lid by detecting the ambient temperature of the substrate.

2. The lid body has an outer lid, an outer lid cover forming an underside of the outer lid, and a heat sink provided under the outer lid cover, The inner lid is provided below the heat sink, A lid heating means for heating the inner lid is provided between the outer lid cover and the heat sink, 2. The rice cooker according to claim 1, wherein the lid temperature detection means is provided between the outer lid and the outer lid cover.

3. 3. The rice cooker according to claim 1, wherein the lid temperature detection means is a chip element.

4. The rice cooker according to any one of claims 1 to 3, further comprising a determination means for determining whether the temperature of the inner lid is equal to or higher than a predetermined temperature.

5. 5. The rice cooker according to claim 4, wherein the determination means measures the time during which the temperature of the inner lid is equal to or higher than a predetermined temperature, and determines whether the time is equal to or higher than the predetermined time.

6. 6. The rice cooker according to claim 5, further comprising an alarm means for alarming when the determination means determines that the temperature is equal to or higher than the predetermined temperature or the time is equal to or higher than the predetermined time.

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