rice cooker

Abstract

To improve the taste of rice. [Solution] The rice cooker according to this disclosure comprises a pot having a bottom and walls, containing a food to be cooked including water and rice; a main body having an upper opening to house the pot; a coil for induction heating the bottom; a wall heating element that generates heat to heat the walls of the pot; a bottom temperature detection unit for detecting the temperature of the bottom; an internal temperature detection unit for detecting the temperature of the air in the internal space of the pot; and a control unit that controls the power supplied to the coil based on the temperature detected by the bottom temperature detection unit, and independently of the control of the power supplied to the coil, controls the power supplied to the wall heating element based on the temperature detected by the internal temperature detection unit.

Description

Technical Field

[0006] , , , ,

[0005] , , , , ,

[0001] The present disclosure relates to a rice cooker.

Background Art

[0002] Patent Document 1 discloses a rice cooker including a pot having a heating element at the bottom, a main body housing the pot, a bottom heating source provided in the main body for inductively heating the heating element, a side heating source provided in the main body for heating the body portion of the pot, and a temperature sensor for detecting the temperature of the bottom of the pot.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The rice cooker of Patent Document 1 still has room for improvement from the viewpoint of improving the taste of the rice.

[0005] The present disclosure aims to improve the taste of the rice.

Means for Solving the Problems

[0006] <00​​​​​​​​​​​​​​A control unit controls the power supplied to the coil based on the temperature detected by the bottom temperature detection unit, and independently of the control of the power supplied to the coil, controls the power supplied to the wall heating element based on the temperature detected by the internal temperature detection unit. It is equipped with. [Effects of the Invention]

[0007] According to the rice cooker of the above-described embodiment, the taste of the rice can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of a rice cooker according to an embodiment of the present disclosure, showing the lid in a closed state. [Figure 2] This is a perspective view of a rice cooker according to an embodiment of the present disclosure, showing the lid in an open state. [Figure 3] Figure 1 is a cross-sectional view of the rice cooker along the line A1-A1. [Figure 4] Figure 1 is a block diagram showing the schematic configuration of the rice cooker. [Figure 5] Figure 1 is a schematic diagram showing the relationship between the temperature of the food being cooked and the power supplied to the bottom heating coil when cooking rice in the rice cooker. [Figure 6] Figure 1 is a schematic diagram showing the relationship between the detected temperature of each temperature sensing unit and the power supplied to the wall heating element, lid heating element, and bottom heating coil during the keep-warm function of the rice cooker. [Modes for carrying out the invention]

[0009] <Knowledge that forms the basis of this disclosure> The disclosers, through diligent research into improving the taste of rice, obtained the following findings.

[0010] Conventional rice cookers typically use a bottom heating element (a coil) to inductively heat the bottom of the pot, while a side heating element (a self-heating heating element) conducts heat to the pot's walls. The voltage supplied to the side heating element from an external power source (for example, the voltage of the commercial power supply in the area where the rice cooker is used) may be applied directly to the side heating element without adjustment. In this case, the heating power of the heating element changes depending on the magnitude of the voltage supplied to the rice cooker from the external power source (hereinafter also referred to as the supply voltage).

[0011] On the other hand, the bottom heating source, which is a coil, is supplied with a current whose voltage and frequency are adjusted by an inverter. Therefore, the heating force of the coil does not change easily even if the supply voltage varies. As a result, the ratio between the heating force of the bottom heating source and the heating force of the heating element may change depending on the difference in supply voltage. This change in ratio reduces the consistency of the taste of the rice.

[0012] For example, in conventional rice cookers, during the warming process, when the temperature at the bottom of the pot reaches a predetermined temperature, the power supply to the bottom and side heating sources is stopped, and when the temperature falls below the predetermined temperature, the power supply to the bottom and side heating sources is restarted. If the supply voltage is high, the heating power of the side heating sources becomes strong, and the top of the rice, which is mainly heated by the side heating sources, dries out. On the other hand, if the supply voltage is low, the heating power of the side heating sources becomes weak, and the temperature of the top of the rice falls below the temperature desired for warming. In this case, condensation accumulates at the bottom of the pot, and the rice at the bottom, which is exposed to the condensation, becomes excessively soft.

[0013] To suppress such deterioration in taste, it is conceivable to pre-change the ratio according to the voltage of the external power supply, for example, the voltage of the commercial power supply in the region where the rice cooker will be used (i.e., the destination of the rice cooker). However, in this case, it would be necessary to develop multiple control logics corresponding to multiple voltages. Furthermore, if multiple control logics are used depending on the supply voltage, it would be necessary to provide a means for detecting the supply voltage in the rice cooker, which is disadvantageous in terms of space efficiency and component costs of the rice cooker itself.

[0014] Therefore, the present inventors have found a configuration in which the control unit independently controls the supply power to the bottom heating coil and the wall heating element based on the detected temperatures of different temperature detection units. According to this configuration, since the heating power of the wall heating element is controlled independently of the control of the heating power of the bottom heating coil and does not depend on the supply voltage, the ratio can be maintained at the desired ratio even when the supply voltage varies. Therefore, the taste of the rice can be improved. Based on this new finding, the present inventors have arrived at the following disclosure.

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, terms indicating a specific direction or position (for example, terms including "up", "down", "right", and "left") are used as necessary, but the use of these terms is for facilitating the understanding of the present disclosure with reference to the drawings, and the technical scope of the present disclosure is not limited by the meanings of these terms. Further, the following description is merely illustrative in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0016] <Embodiment> An example of a rice cooker according to an embodiment of the present disclosure will be described. FIG. 1 is a perspective view of a rice cooker according to an embodiment of the present disclosure, showing a state in which the lid is closed. FIG. 2 is a perspective view of a rice cooker according to an embodiment of the present disclosure, showing a state in which the lid is open. FIG. 3 is a cross-sectional view of the rice cooker of FIG. 1 taken along line A1 - A1.

[0017] As shown in FIG. 1 or FIG. 2, the rice cooker according to the present embodiment includes a substantially bottomed cylindrical main body 1 and a lid 2 that opens and closes the upper opening 1A of the main body 1 in a freely detachable manner.

[0018] As shown in FIG. 2, the main body 1 is provided with a bottomed cylindrical pot storage portion 1C for detachably storing a pot 3. The pot 3 contains the rice to be cooked, such as rice and water. As shown in FIG. 3, the pot � has a bottom portion 3A and a wall portion 3C that extends upward from the outer edge portion 3B of the bottom portion 3A in a plan view. The upper edge portion of the wall portion 3C defines the opening 3D of the pot 3.

[0019] As shown in Figures 1 and 2, the main unit 1 is provided with a selection unit 4 on its side for setting the cooking process of the food to be cooked in the pot 3. The selection unit 4 includes, for example, a liquid crystal display that displays various information such as the cooking course and cooking time, and multiple buttons for selecting the cooking course and for instructing actions such as starting, canceling, and scheduling cooking. The user can refer to the various information displayed on the liquid crystal display and select a specific cooking course using the multiple buttons to start cooking. The selection unit 4 may also include, for example, a touch panel.

[0020] The lid 2 has a hollow structure and is attached to the upper part of the main body 1 via a hinge portion 1B. The lid 2 is configured to open and close the upper opening 1A of the main body 1 by rotating around the hinge portion 1B. That is, the lid 2 is configured to rotate between a closed position (see Figure 1) that closes the upper opening 1A of the main body 1 and an open position (see Figure 2) that opens the upper opening 1A of the main body 1.

[0021] As shown in Figure 1, the lid 2 is provided with a steam outlet 2A that discharges steam generated inside the pot 3 to the outside of the rice cooker. The steam outlet 2A is provided to be in fluid communication with the internal space of the pot 3. In this embodiment, the user can confirm that the food being cooked inside the pot 3 is boiling over to the outside of the pot 3 by visually observing the food boiling over from the steam outlet 2A.

[0022] As shown in Figure 3, a substantially disc-shaped inner lid 2B capable of sealing the opening 3D of the pot 3 is attached to the lower side of the lid 2 (the surface that covers the upper opening 1A of the main body 1). In this embodiment, the inner lid 2B is made of metal and is detachably attached to the lid 2. The inner lid 2B is an example of a heating plate in this disclosure.

[0023] Inside the lid 2, there is a lid heating element 2C that generates heat on its own to heat the inner lid 2B, and an internal temperature sensing unit 2D that detects the temperature of the air in the internal space of the pot 3. Here, the internal space of the pot 3 is, for example, the space between the opening surface of the pot 3 and the top surface of the food being cooked.

[0024] In this embodiment, the lid heating element 2C is a heat-generating resistor located near the inner lid 2B, and the heat from the lid heating element 2C is conducted to the inner lid 2B, thereby heating the inner lid 2B. The inner lid 2B heats the air inside the pot 3 during the cooking and warming processes.

[0025] The internal temperature detection unit 2D is, for example, a temperature sensor that detects the temperature of the inner lid 2B. In this embodiment, the internal temperature detection unit 2D is positioned so as to be in contact with the inner lid 2B. Since the temperature of the air in the internal space of the pot 3 is approximately the same as the temperature of the inner lid 2B, the internal temperature detection unit 2D can detect the temperature of the air in the internal space of the pot 3 by detecting the temperature of the inner lid 2B. The temperature detected by the internal temperature detection unit 2D may also be approximately the same as the temperature of the top of the rice.

[0026] The rice cooker according to this embodiment includes a bottom heating coil 51 provided in the main body 1 for induction heating of the bottom 3A of the pot 3, a wall heating element 52 for heating the wall 3C of the pot 3, a bottom temperature detection unit 6 for detecting the temperature of the bottom 3A of the pot 3, and a control unit 7 that performs a rice cooking process and a warming process following the rice cooking process.

[0027] The bottom heating coil 51 is positioned opposite the bottom 3A of the pot 3. In this embodiment, the bottom heating coil 51 comprises an annular inner bottom heating coil 51a positioned opposite the central part of the bottom 3A of the pot 3, and an annular outer bottom heating coil 51b positioned opposite the corners of the bottom 3A of the pot 3. The inner bottom heating coil 51a induces heating around the central part of the bottom 3A of the pot 3. The outer bottom heating coil 51b is located outside the inner bottom heating coil 51a in a plan view taken from the depth direction of the pot storage section 1C, and induces heating of the outer edge 3B of the bottom 3A of the pot 3.

[0028] The wall heating element 52 generates heat on its own to heat the wall portion 3C of the pot 3. For example, the wall heating element 52 is installed inside the main body 1 and is positioned around the pot 3 so as to face the wall portion 3C of the pot 3. In this embodiment, the wall heating element 52 is a heat-resistant element, and the heat generated by the wall heating element 52 is conducted to the wall portion 3C, thereby heating the wall portion 3C. During the cooking and warming process, the wall heating element 52 mainly heats the upper part of the cooked food (or rice) via the wall portion 3C.

[0029] The bottom temperature detection unit 6 is, for example, a temperature sensor that detects the temperature of the bottom 3A of the pot 3. In this embodiment, the bottom temperature detection unit 6 is positioned so as to be able to contact the center of the bottom 3A of the pot 3 housed in the main body 1. Since the temperature of the pot 3 is approximately the same as the temperature of the food being cooked inside the pot 3, the temperature of the food being cooked inside the pot 3 can be detected by the bottom temperature detection unit 6 detecting the temperature of the pot 3.

[0030] The control unit 7 controls the heating operation of the bottom heating coil 51, the wall heating element 52, and the lid heating element 2C based on the temperature detected by at least one of the internal temperature detection unit 2D and the bottom temperature detection unit 6, and performs the rice cooking process and the warming process. In this embodiment, the control unit 7 is located inside the main body 1, below the pot 3.

[0031] Figure 4 is a block diagram showing the schematic configuration of the rice cooker in Figure 1. The rice cooker according to this embodiment further includes a power connection unit 81 that can be connected to a power source that supplies power to the rice cooker, and a rectifier circuit 82 connected between the power connection unit 81 and the bottom heating coil 51.

[0032] The power connection section 81 is the connection point to an external power source, such as a commercial power supply, generator, or energy storage device. A portion of the power connection section 81 is exposed to the outside for connection to the external power source, but this is omitted in Figures 1 and 2. In this embodiment, the power connection section 81 is a plug that connects to an outlet. AC voltage is supplied to the power connection section 81 as power. The rectifier circuit 82 rectifies the AC power supplied through the power connection section 81.

[0033] An inverter circuit 71 is connected between the rectifier circuit 82 and the bottom heating coil 51. The inverter circuit 71 converts the DC or low-frequency current output from the rectifier circuit 82 into a high-frequency current and supplies it to the bottom heating coil 51. The inverter circuit 71 adjusts the power supplied to the bottom heating coil 51 by changing at least one of the energization rate and frequency of the high-frequency current supplied to the bottom heating coil 51.

[0034] The inverter circuit 71 is connected to the control unit 7. For example, the control unit 7 is a microcomputer. The control unit 7 outputs a drive signal to the inverter circuit 71 to drive the bottom heating coil 51. In this embodiment, the drive signal is a pulse width modulation (PWM) signal. A PWM signal is a pulse wave that repeatedly switches on and off at a period of a certain amount of time, and control is performed by changing the ratio of the on time (duty cycle) in each cycle. In this embodiment, the larger the duty cycle of the drive signal, the greater the power supplied to the bottom heating coil 51 per unit time.

[0035] On the other hand, the wall heating element 52 and the lid heating element 2C are connected to the power supply connection section 81 without going through the rectifier circuit 82 and the inverter circuit 71. As a result, the voltage applied to the power supply connection section 81 from the external power supply is applied to the wall heating element 52 without being boosted or stepped down. In other words, the voltage applied to the wall heating element 52 depends on the output voltage of the external power supply. In this embodiment, the voltage applied to the lid heating element 2C is also applied to the power supply connection section 81 without being boosted or stepped down.

[0036] A heating element switching unit 72 is connected between the power connection unit 81 and the two heating elements 52,2C. The heating element switching unit 72 is configured to switch between supplying power to the two heating elements 52,2C and stopping the power supply.

[0037] The control unit 7 outputs a drive signal to the heating element switching unit 72 to supply power to the two heating elements 52,2C. In this embodiment, the drive signal is a pulse width modulated signal. In this embodiment, the larger the duty cycle of the drive signal, the less power is supplied to each heating element 52,2C per unit time.

[0038] The control unit 7 includes a memory unit that stores at least one cooking sequence for cooking rice and at least one keep-warm sequence for keeping the cooked rice warm. Here, a "cooking sequence" refers to a rice cooking procedure in which the five main steps shown in Figure 5—preheating, heating, power reduction, boiling maintenance, and steaming—are performed in sequence, with predetermined parameters such as the power supply time, heating temperature, heating time, and heating output for each step. For example, multiple cooking sequences correspond to multiple cooking courses that can be executed in the rice cooker. A "keep-warm sequence" refers to a keep-warm procedure in which the power supply time, heating temperature, heating time, and heating output for the keep-warm process, described later, are predetermined. The control unit 7 executes the cooking process and the keep-warm process according to the cooking sequence and the keep-warm sequence, based on the temperatures detected by the bottom temperature detection unit 6 and the internal temperature detection unit 2D.

[0039] Figure 5 is a schematic diagram showing the relationship between the temperature of the food being cooked and the power supplied to the bottom heating coil when cooking is performed in the rice cooker shown in Figure 1.

[0040] When the selection unit 4 selects various rice cooking information and issues an instruction to start rice cooking, the control unit 7 executes a preheating process.

[0041] The preheating process involves soaking the rice in water at a temperature lower than the gelatinization start temperature of rice (approximately 60°C) to allow the rice to absorb water in advance. During the preheating process, the control unit 7 heats the pot 3 to a preheating temperature lower than the gelatinization start temperature of rice (for example, 50°C) and controls the bottom heating coil 51 and the two heating elements 52,2C to maintain the rice being cooked at that preheating temperature. After a predetermined time (for example, 20 minutes) has elapsed from the start of the preheating process, the process moves to the heating step.

[0042] The heating process is the process of raising the temperature of the food to be cooked in the pot 3 to just before the boiling point. During the heating process, the control unit 7 controls the bottom heating coil 51 and the two heating elements 52,2C so that the temperature of the food to be cooked in the pot 3 rises to just before the boiling point. When the temperature detected by the bottom temperature detection unit 6 rises to a predetermined temperature (for example, 98°C), the process moves to the power-down process.

[0043] The power-down (hereinafter also referred to as PD) process is a process of reducing the heating power of the bottom heating coil 51 and the two heating elements 52,2C in order to prevent the food being cooked from boiling over to the outside of the pot 3. The power-down process ends, for example, after a predetermined time (for example, 1 minute) has elapsed since the start of the power-down process. After the power-down process ends, the process moves to the boiling maintenance process.

[0044] The boiling maintenance process is a process that maintains the boiling state of the rice being cooked in the pot 3 to gelatinize the starch in the rice and raise the degree of gelatinization to, for example, 50% to 80%. In the boiling maintenance process, the control unit 7 controls the bottom heating coil 51 and the two heating elements 52,2C to heat the pot 3 with a lower heating amount than in the heating rise process. When the water in the pot 3 is gone and the temperature detected by the bottom temperature detection unit 6 is above the boiling point of water (for example, 130°C), the process moves to the steaming process.

[0045] The steaming process utilizes residual heat to evaporate excess moisture from the rice, thereby steaming it and increasing its gelatinization to nearly 100%. During the steaming process, the control unit 7 controls the bottom heating coil 51 and the two heating elements 52,2C to gradually lower the temperature of the cooked food to a predetermined steaming temperature (e.g., 100°C) and then maintain that steaming temperature. For example, the control unit 7 controls the bottom heating coil 51 and the two heating elements 52,2C to heat the pot 3 with a stronger heating force than when maintaining the steaming temperature until the temperature of the cooked food drops to the steaming temperature. After a predetermined time (e.g., 20 minutes) has elapsed from the start of the steaming process, the cooking process ends and the process moves to the keep-warming process.

[0046] Figure 6 is a schematic diagram showing the relationship between the detected temperature of each temperature sensing unit and the power supplied to the wall heating element, lid heating element, and bottom heating coil during the warming process of the rice cooker shown in Figure 1. As shown in Figure 6, the warming process includes a cooling process that lowers the temperature of the cooked food to a predetermined warming temperature, and a temperature maintenance process that maintains the cooked food at the warming temperature after the cooling process.

[0047] Simultaneously with the start of the heat retention process, the cooling process begins. During the cooling process, the control unit 7 controls the inverter circuit 71 to stop supplying power to the bottom heating coil 51. The control unit also controls the heating element switching unit 72 to stop supplying power to the wall heating element 52. Meanwhile, the control unit 7 controls the heating element switching unit 72 to drive the lid heating element 2C with a duty cycle of 1 / 16.

[0048] During the cooling process, the temperature of the rice and the air inside the pot 3 decreases. Consequently, the temperatures detected by the bottom temperature detection unit 6 and the internal temperature detection unit 2D also decrease. When the temperature detected by the bottom temperature detection unit 6 falls below 70°C, the process transitions to the temperature maintenance process.

[0049] In the temperature maintenance process, the control unit 7 independently controls the driving of the bottom heating coil 51, the wall heating element 52, and the lid heating element 2C based on different temperature detection units. With respect to the bottom heating coil 51, when the temperature detected by the bottom temperature detection unit 6 falls below the first temperature, the control unit 7 drives the bottom heating coil 51 with a duty cycle of 1 / 16. In this embodiment, the first temperature is 70°C. On the other hand, when the temperature detected by the bottom temperature detection unit 6 rises to or above the first temperature, the control unit 7 stops driving the bottom heating coil 51. As a result, the temperature of the bottom 3A of the pot 3 and the bottom of the rice is maintained around the first temperature.

[0050] Regarding the wall heating element 52 and the lid heating element 2C, the control unit 7 drives the wall heating element 52 and the lid heating element 2C with a duty cycle of 16 / 16 when the temperature detected by the internal temperature detection unit 2D falls below the second temperature. Here, the second temperature is higher than the first temperature. In this embodiment, the second temperature is 74°C. On the other hand, when the temperature detected by the internal temperature detection unit 2D rises to or above the second temperature, the control unit 7 stops driving both the wall heating element 52 and the lid heating element 2C. As a result, the temperature of the air above the rice and in the internal space of the pot 3 is maintained at around the second temperature, which is higher than the first temperature.

[0051] According to the embodiment of this disclosure, the control unit 7 controls the power supplied to the wall heating element 52 based on the temperature detected by the internal temperature detection unit 2D, independently of the control of the power supplied to the bottom heating coil 51. In other words, the power supplied to the wall heating element 52 is controlled based on the temperature detected by a temperature detection unit different from that of the bottom temperature detection unit 6, which is the basis for controlling the bottom heating coil 51. As a result, even if the voltage supplied to the rice cooker from an external power source (for example, the commercial power supply in the area where the rice cooker is used) varies, the heating power of the wall heating element 52 can be maintained at a predetermined level. Therefore, since the heating ratio between the bottom heating coil 51 and the wall heating element 52 is maintained independently of the voltage supplied from the external power source, it is possible to suppress a decrease in the stability of the taste of the rice due to differences in the voltage of the external power source. Therefore, the taste of the rice can be improved.

[0052] One possible method for maintaining the heating ratio independently of the external power supply voltage is to use multiple control logics depending on several possible supply voltages (for example, the voltage of the commercial power supply in the destination country of the rice cooker). However, the more control logics used, the more time and cost are required for their development. Furthermore, if multiple control logics stored within the rice cooker are to be used interchangeably depending on the supply voltage, it is necessary to provide a means for detecting the supply voltage in the rice cooker, which is disadvantageous in terms of space efficiency and component cost of the rice cooker body. On the other hand, according to the above embodiment, the desired heating ratio can be achieved with a single control logic, regardless of the supply voltage, which is advantageous compared to the above method in terms of development time and cost, as well as space efficiency and component cost of the rice cooker body 1.

[0053] According to the embodiment of this disclosure, the bottom heating coil 51 is supplied with a voltage adjusted to a predetermined value by the inverter circuit 71, while the wall heating element 52 is supplied with the voltage applied to the power connection 81. In this case, the heating force of the bottom heating coil 51 is constant regardless of the supply voltage, while the heating force of the wall heating element 52 fluctuates according to the supply voltage.

[0054] According to the above embodiment, the control unit 7 controls the power supplied to the wall heating element 52 based on the temperature detected by a temperature detection unit different from the bottom temperature detection unit 6, which is the basis for controlling the bottom heating coil 51. As a result, even if the supply voltage varies, the heating power of the bottom heating coil 51 and the wall heating element 52 is maintained, so that the stability of the taste of the rice caused by differences in the voltage of the external power supply can be suppressed. Therefore, the taste of the rice can be further improved.

[0055] The top of the cooked rice cools down more easily than the bottom because it is in contact with the air inside the pot 3. When the temperature of the top of the rice drops, condensation forms between the rice grains and on the walls of the pot, causing the rice at the top to become watery. Furthermore, if this condensation moves downward due to gravity and accumulates at the bottom 3A of the pot 3, the rice near the bottom 3A may become watery as it is exposed to the accumulated condensation.

[0056] According to the embodiment of this disclosure, the control unit 7 drives the wall heating element 52 when the temperature detected by the internal temperature detection unit 2D is below the second temperature, and stops it when the detected temperature is at or above the second temperature. Here, the second temperature is set to a temperature higher than the first temperature which serves as the basis for driving and stopping the bottom heating coil 51. This suppresses an unintended drop in the temperature of the top of the rice and reduces the amount of condensation generated inside the pot 3. As a result, the wateriness of the rice is improved, and the taste of the rice can be further enhanced.

[0057] When the pot 3 and the heating plate 2B are heated by different heating elements, a large temperature difference can occur between the pot 3 and the heating plate 2B, which can easily degrade the taste of the rice. For example, if the temperature of the pot 3 is significantly higher than the temperature of the heating plate 2B, the portion of the rice adjacent to the pot 3 will dry out and turn yellow due to overheating. On the other hand, condensation is more likely to form on the heating plate 2B, which is at a relatively lower temperature. As a result, the top of the rice becomes watery and prone to whitening due to the condensation that falls from the heating plate 2B. Also, for example, if the temperature of the heating plate 2B is significantly higher than the temperature of the pot 3, the top of the rice will receive excessive radiant heat from the heating plate 2B, causing it to dry out and turn yellow. On the other hand, the area near the pot 3 will be at a lower temperature than the top of the rice heated by the heating plate 2B, causing condensation to form, and the rice will become watery and prone to whitening.

[0058] According to the embodiment of this disclosure, the control unit 7 controls the heating element 52 in the heat retention process based on a comparison between the temperature detected by the internal temperature detection unit 2D and the second temperature, similar to the control of the wall heating element 52. That is, the control unit 7 drives the lid heating element 2C when the temperature detected by the internal temperature detection unit 2D is less than the second temperature, and stops it when the detected temperature is the second temperature or higher. This makes it easier to maintain the temperature difference between the pot 3 and the heating plate 2B within the desired temperature difference range. In addition, it suppresses an unintended drop in the temperature of the air inside the pot 3, and reduces the amount of condensation generated inside the pot 3. Therefore, the wateriness and dryness of the rice are improved, and the taste of the rice can be further enhanced.

[0059] This disclosure is not limited to the embodiments described above, and can be implemented in various other ways. For example, in the above description, the control unit 7 controls the power supplied to the wall heating element 52 based on the temperature detected by a temperature detection unit different from the bottom temperature detection unit 6, which is the basis for controlling the bottom heating coil 51, but this disclosure is not limited to this. For example, the control unit 7 may perform the above control in at least one of the steps included in the rice cooking process: preheating, temperature rise, PD, boiling maintenance, and steaming.

[0060] In the temperature maintenance process, the control unit 7 stops the corresponding bottom heating coil 51 or the wall heating element 52 and lid heating element 2C when the temperature detected by the bottom temperature detection unit 6 or the internal temperature detection unit 2D reaches or exceeds the corresponding first or second temperature. However, the disclosure is not limited thereto. For example, instead of stopping the bottom heating coil 51 or the two heating elements 52,2C, the control unit 7 may reduce the duty cycle while maintaining operation.

[0061] In the temperature maintenance process, the control unit 7 controls the driving and stopping of both the wall heating element 52 and the lid heating element 2C based on the temperature detected by the internal temperature detection unit 2D, but the disclosure is not limited thereto. For example, the control unit 7 may maintain the heating element 2C in an driven or stopped state independently of the temperature detected by the internal temperature detection unit 2D during the temperature maintenance process. Alternatively, the control unit 7 may control the driving and stopping of the lid heating element 2C based on the temperature detected by another temperature detection unit different from the bottom temperature detection unit 6 and the internal temperature detection unit 2D.

[0062] In the above embodiment, the power-down process is initiated after the temperature detected by the bottom temperature detection unit 6 rises to a predetermined temperature (for example, 98°C), but this disclosure is not limited thereto. For example, the bottom temperature detection unit 6 may be placed on the lid 2 to detect the temperature of the steam generated in the pot 3, and the power-down process may be initiated after the temperature detected by the bottom temperature detection unit 6 rises to a predetermined temperature (for example, 70°C).

[0063] By appropriately combining any embodiment or modification from the various embodiments or modifications described above, the effects of each can be achieved. Furthermore, combinations of embodiments with each other, combinations of examples with each other, and combinations of embodiments with examples are possible, as well as combinations of features from different embodiments or examples.

[0064] While this disclosure is adequately described in relation to preferred embodiments with reference to the accompanying drawings, various variations and modifications will be obvious to those skilled in the art. Such variations and modifications should be understood to be included within the scope of this disclosure as defined by the attached claims.

[0065] <Overview of Embodiments> [Item 1] A pot having a bottom and a wall portion extending from the outer edge of the bottom, which contains water and rice to be cooked, A main body having an upper opening, through which the pot is housed, A coil provided in the main body for induction heating of the bottom, A wall heating element is provided in the main body and generates heat to heat the wall portion of the pot, The bottom temperature detection unit detects the temperature of the bottom, An internal temperature detection unit that detects the temperature of the air inside the pot, A control unit controls the power supplied to the coil based on the temperature detected by the bottom temperature detection unit, and independently of the control of the power supplied to the coil, controls the power supplied to the wall heating element based on the temperature detected by the internal temperature detection unit. A rice cooker equipped with [a specific feature].

[0066] [Item 2] A power connection section that can be connected to a power supply that provides power to the rice cooker, An inverter is connected between the power supply connection and the coil to adjust the voltage of the current supplied to the coil, Equipped with, The voltage applied to the power supply connection is applied to the heat-generating element in the wall. The rice cooker listed in item 1.

[0067] [Item 3] The control unit performs a cooking step to cook the food to be cooked and a warming step to keep the cooked rice warm. The control unit, in the heat retention process, When the temperature detected by the bottom temperature detection unit is less than the first temperature, the coil is driven, and when the temperature detected by the bottom temperature detection unit is equal to or greater than the first temperature, the coil is stopped. When the temperature detected by the internal temperature detection unit is less than the second temperature which is higher than the first temperature, the wall heating element is driven, and when the temperature detected by the internal temperature detection unit is the second temperature or higher, the wall heating element is stopped. A rice cooker as described in item 1 or 2.

[0068] [Item 4] A lid attached to the main body, which can open and close to cover the upper opening, A heating plate attached to the lid, which covers the opening of the pot when the lid is in a closed state covering the upper opening, A lid heating element is provided on the lid and generates heat to heat the heating plate, Equipped with, The control unit, in the heat retention process, drives the lid heating element when the temperature detected by the internal temperature detection unit is less than the second temperature, and drives the lid heating element when the temperature detected by the internal temperature detection unit is equal to or greater than the second temperature. The rice cooker described in item 3. [Industrial applicability]

[0069] The rice cooker described herein is useful as a rice cooker for both consumer and commercial use because it can improve the taste of rice. [Explanation of Symbols]

[0070] 1 Main unit 1A Top opening 1B Hinge section 1C Pot storage section 2 Lid 2A Steam outlet 2B Inner lid 2C Cover Heating Element 2D internal temperature detection unit 3 Pot 3A bottom 3B Outer edge 3C wall 3D opening 4. Selection Section 6. Bottom temperature detection unit 7 Control Unit 51 Bottom heating coil 51a Bottom heating coil 51b Bottom external heating coil 52 Wall heating element 71 Inverter Circuit 72 Heating element switching section 81 Power connection section 82 Rectifier circuit

Claims

1. A pot having a bottom and a wall portion extending from the outer edge of the bottom, which contains water and rice to be cooked, A main body having an upper opening, through which the pot is housed, A coil provided in the main body for induction heating of the bottom, A wall heating element is provided in the main body and generates heat to heat the wall portion of the pot, The bottom temperature detection unit detects the temperature of the bottom, An internal temperature detection unit that detects the temperature of the air inside the pot, A control unit controls the power supplied to the coil based on the temperature detected by the bottom temperature detection unit, and independently of the control of the power supplied to the coil, controls the power supplied to the wall heating element based on the temperature detected by the internal temperature detection unit. A rice cooker equipped with [a specific feature].

2. A power connection section that can be connected to a power supply that provides power to the rice cooker, An inverter is connected between the power supply connection and the coil to adjust the voltage of the current supplied to the coil, Equipped with, The voltage applied to the power supply connection is applied to the heat-generating element in the wall. The rice cooker according to claim 1.

3. The control unit performs a cooking step to cook the food to be cooked and a warming step to keep the cooked rice warm. The control unit, in the heat retention process, When the temperature detected by the bottom temperature detection unit is less than the first temperature, the coil is driven, and when the temperature detected by the bottom temperature detection unit is equal to or greater than the first temperature, the coil is stopped. When the temperature detected by the internal temperature detection unit is less than the second temperature which is higher than the first temperature, the wall heating element is driven, and when the temperature detected by the internal temperature detection unit is the second temperature or higher, the wall heating element is stopped. A rice cooker according to claim 1 or 2.

4. A lid attached to the main body, which can open and close to cover the upper opening, A heating plate attached to the lid, which covers the opening of the pot when the lid is in a closed state covering the upper opening, A lid heating element is provided on the lid and generates heat to heat the heating plate, Equipped with, The control unit drives the lid heating element when the temperature detected by the internal temperature detection unit is less than the second temperature during the heat retention process, and drives the lid heating element when the temperature detected by the internal temperature detection unit is equal to or greater than the second temperature. The rice cooker according to claim 3.

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