Rice cooker

Abstract

To provide a rice cooker capable of smoothly discharging liquid entering the inside of a lid body from a gap between a panel corresponding to a top plate of the lid body and its adjacent member.SOLUTION: A rice cooker 1 includes a pot 25 capable of storing a material to be cooked, a body 23 having a pot 25 storage part capable of storing the pot 25, and a lid body 26 capable of opening and closing the pot 25 storage part. The lid body 26 includes an outer lid cover 56 that covers the body 23 in a state where the lid body 26 closes the body 23, an outer lid 55 that has a recessed portion 55a opened in a direction away from the body 23 and covers the outer lid cover 56, and the operation panel 73 as an upper surface panel that covers the recessed portion 55a. The outer lid 55 includes a drain groove 82 that is provided along at least a part of the edge of the recessed portion side 55a and guides the liquid to a hole 81 through which the liquid flows out to a space defined by the outer lid 55 and the outer lid cover 56 when the liquid enters the recessed portion 55a through the gap between the operation panel 73 and the outer lid 55.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a rice cooker. [Background technology]

[0002] There is known a rice cooker that includes a pot capable of containing food to be cooked, a main body having a pot housing portion capable of housing the pot, a lid capable of opening and closing the pot housing portion, a hinge mechanism that connects the lid to the main body so that it can be opened and closed, and a locking mechanism that locks the lid that closes the main body so that it can be opened and closed. The lid includes an outer lid cover that corresponds to the bottom plate and a panel that corresponds to the top plate. The locking mechanism includes a lid operating body that releases the lock. The lid operating body penetrates the inside and outside of the lid through an opening or hole provided in the panel of the lid. When the lid operating body is pressed in, the locking mechanism is released.

[0003] If liquid, such as water, is spilled on the top surface of the lid, it will seep into the lid through the small gap between the lid operating mechanism and the panel opening. The liquid that seeps into the lid is received by the outer lid cover, which corresponds to the bottom plate of the lid, and then drains down the outer lid cover to the outside of the rice cooker. In other words, the outer lid cover functions as a drain pan. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-151879 Summary of the Invention [Problem to be solved by the invention]

[0005] The panel of the cover may have a design surface for a touch key as an input device or a transparent window for a display device. In such cases, a circuit board on which the input device or display device is mounted may be housed in the cover. In such a cover, a small gap will be formed between the panel and a component adjacent to the panel, such as a component having a circuit board housing portion for housing the circuit board.

[0006] The lid body needs to discharge outside the machine any liquid that enters the interior of the lid body through the gap between the panel and a component adjacent to the panel, just as it needs to discharge any liquid that enters the interior of the lid body through the gap between the lid body operating body and the opening in the lid body.

[0007] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rice cooker that can smoothly drain liquid that enters the inside of the lid through the gap between the panel corresponding to the top plate of the lid and its adjacent member. [Means for solving the problem]

[0008] In order to solve the above problems, a rice cooker according to an embodiment of the present invention comprises a pot capable of accommodating the food to be cooked, a main body having a pot accommodating section capable of accommodating the pot, and a lid body capable of opening and closing the pot accommodating section, wherein the lid body comprises an outer lid cover that covers the main body when the lid body is closed, an outer lid having a recessed section that opens away from the main body and covers the outer lid cover, and a top panel that covers the recessed section, and the outer lid has a drain groove provided along at least a portion of the edge of the recessed section that, if liquid seeps into the recessed section through the gap between the top panel and the outer lid, directs the liquid to a hole that allows the liquid to flow out into the space partitioned by the outer lid and the outer lid cover. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a rice cooker according to an embodiment of the present invention; [Figure 2] 1 is a vertical cross-sectional view of a rice cooker according to an embodiment of the present invention. [Figure 3] FIG. 2 is a cross-sectional view of the inner frame and heating coil of the rice cooker according to the embodiment. [Figure 4] FIG. 2 is a bottom view of the inner frame and heating coil of the rice cooker according to the embodiment. [Figure 5] FIG. 2 is an exploded perspective view of the rice cooker according to the embodiment, showing the state in which the operation panel of the lid body is removed. [Figure 6] FIG. 2 is a plan view of the outer lid of the rice cooker according to the present embodiment. [Figure 7] FIG. 2 is an enlarged cross-sectional view of the outer lid of the rice cooker according to the present embodiment, taken along a plane that intersects the circuit board accommodating recess in the width direction of the rice cooker. [Figure 8] FIG. 2 is an enlarged cross-sectional view of the outer lid of the rice cooker according to the present embodiment, taken along the drain groove. DETAILED DESCRIPTION OF THE INVENTION

[0010] A rice cooker according to the present invention will be described below with reference to Figures 1 to 8. Note that the same or corresponding components are denoted by the same reference numerals throughout the drawings.

[0011] FIG. 1 is a perspective view of a rice cooker according to an embodiment of the present invention.

[0012] FIG. 2 is a vertical cross-sectional view of the rice cooker according to the embodiment of the present invention.

[0013] 1 is a perspective view of the rice cooker 1 according to this embodiment, viewed from diagonally above the front right. In other words, the front, right side, and top of the rice cooker 1 are visible in FIG. 2, while the back, left side, and bottom of the rice cooker 1 are hidden.

[0014] 1 and 2, rice cooker 1 according to this embodiment includes rectangular main body 23 having pot housing section 21 that opens upward, pot 25 housed in pot housing section 21, lid 26 that fits over the top of main body 23 to open and close pot housing section 21, hinge mechanism 27 that supports lid 26 on main body 23 so that it can be opened and closed, and a power line that can be connected to an external power source, such as a commercial AC power outlet. When lid 26 is opened upward on main body 23, pot 25 can be removed from pot housing section 21.

[0015] Rice cooker 1 heats and cooks rice and water contained in pot 25 using heating coil 31, and keeps the cooked rice warm by heating it using heating coil 31. Rice cooker 1 cooks the food using a cooking course that is selectively selected from a plurality of cooking courses.

[0016] Each cooking course has cooking conditions for cooking rice to rice. The cooking conditions include, for example, the type of rice, the cooking method for cooking the rice to rice, the hardness of the cooked rice, and the cooking time for cooking the rice to rice. Each cooking course includes at least two of these cooking conditions.

[0017] Each rice cooking course heats the food in pot 25 at a predetermined pressure. Each rice cooking course has processes that are set according to the brand of rice and the rice polishing ratio. Each process includes, for example, a soaking process that promotes the water absorption of rice placed in pot 25, a boiling and heating process that quickly raises the temperature of the food to the boiling point, a boiling continuation process that continues to boil the food, and a soaking process that maintains the temperature at a high enough temperature to prevent the rice from burning. Rice cooker 1 can also perform a warming process that keeps the rice in pot 25 at a predetermined warm temperature, either separately from the rice cooking course or consecutively to the rice cooking course.

[0018] Rice cooker 1 can also execute a cooking course that heats food other than the food placed in pot 25 using a predetermined heating pattern. Food includes the food to be cooked unless otherwise specified. Rice cooker 1 can also execute a maintenance course that boils water placed in pot 25 to use steam to lift dirt and remove odors from hard-to-clean parts inside rice cooker 1. For ease of explanation, the rice cooking course, cooking course, and maintenance course will hereinafter be collectively referred to simply as "courses."

[0019] Pot 25 is also called a "kettle." Pot 25 is a container with a bottom that holds water and rice to be cooked. Pot 25 has a main body 25a made of aluminum, which has high thermal conductivity, and a heating element 25b that is joined to the main body from the lower outer periphery to cover the bottom. The heating element is made of a magnetic metal plate made of ferritic stainless steel, for example. The inside of pot 25 is coated with a fluororesin. The fluororesin coating is formed by applying, for example, polytetrafluoroethylene (PTFE) or perfluoroalkoxy alkane (PFA). Pot 25 has a flange portion 32 that protrudes radially outward and surrounds the entire outer periphery.

[0020] The pot 25 is provided with a flange portion 32 that protrudes radially outward and surrounds the entire periphery of the outer periphery.

[0021] The planar shape of main body 23 is rectangular. Main body 23 defines the front, back, left side, right side, and bottom of rice cooker 1 below lid 26. Main body 23 includes a bottom plate 35 that defines the bottom surface of main body 23, an upper frame 36 that covers the top of bottom plate 35 and defines part of the top surface and the side surfaces of main body 23, a bowl-shaped inner frame 37 that is molded integrally with upper frame 36, and an outer frame 38 that defines the remainder of the top surface of main body 23.

[0022] The bottom plate 35, upper frame 36, and outer frame 38 form the outer shell of the main body 23. The bottom plate 35 and upper frame 36 are molded from synthetic resin, such as polypropylene (PP). The outer frame 38 is molded from a metal material, such as stainless steel.

[0023] Upper frame 36 and inner frame 37 define pot accommodating section 21. Inner frame 37 corresponds to the bottom plate of pot accommodating section 21. Inner frame 37 is a processed product made of, for example, aluminum-plated steel plate.

[0024] Pot accommodating section 21 accommodates pot 25 in a suspended state with the upper edge of pot accommodating section 21 in contact with the underside of flange 32 of pot 25. When pot 25 is accommodated in pot accommodating section 21, flange 32 of pot 25 and the upper edge of pot accommodating section 21 are in contact with each other with almost no gap between them, but flange 32 of pot 25 has a non-contact area along its circumference. This area defines a groove extending from the upper end of pot accommodating section 21 away from pot accommodating section 21. This groove creates a gap between pot accommodating section 21 and flange 32 of pot 25. This gap serves as a passageway for discharging steam generated between pot accommodating section 21 and pot 25 when pot 25 is heated with moisture adhering to its outer surface.

[0025] Main body 23 also has control unit housing chamber 39 defined between the outer casing and pot housing section 21. The outer casing of main body 23 has vent hole 41 that directs outside air into control unit housing chamber 39. Vent hole 41 is preferably located on the bottom or side of main body 23.

[0026] Furthermore, the main body 23 is equipped with a heating control circuit board 42 housed in the control unit housing chamber 39. The heating control circuit board 42 is equipped with a microprocessor and a storage device that stores digital information such as various calculation programs executed by the microprocessor, parameters, etc. The storage device stores various settings (arguments) related to multiple preset courses.

[0027] The main body 23 also includes a heat sink 43 attached to the microprocessor of the heating control circuit board 42 and a cooling fan 45 for blowing air onto the heat sink 43 .

[0028] The heat sink 43 is made of a material with good thermal conductivity, such as aluminum. The cooling fan 45 is located below or to the side of the heat sink 43. The cooling performance of the combined heat sink 43 and cooling fan 45 is set to maintain the temperature of the microprocessor within the operating temperature range. The cooling fan 45 and the vent 41 of the main body 23 are preferably positioned so that they sandwich the pot 25. This positioning relationship contributes to the miniaturization of the product.

[0029] Furthermore, the main body 23 is provided with a heating coil 31 provided on the outer surface of the inner frame 37 and a pot temperature sensor 46 provided in the center of the bottom surface of the inner frame 37 to detect the temperature of the bottom of the pot 25.

[0030] Heating coil 31 is arranged to face the lower outer circumferential surface and bottom surface of pot 25 housed in pot housing section 21. Heating coil 31 generates an alternating magnetic field to heat heating element 25b of pot 25 by electromagnetic induction.

[0031] Pot temperature sensor 46 passes through temperature sensor mounting hole 37a in the center of the bottom surface of inner frame 37 and comes into contact with the bottom surface of pot 25. Pot temperature sensor 46 has a thermistor that detects the temperature of the bottom of pot 25. The temperature of the bottom of pot 25 will hereinafter be referred to as the "pot bottom temperature." Pot temperature sensor 46 is pressed against the bottom surface of pot 25 by spring force. The pot bottom temperature detected by pot temperature sensor 46 is used primarily to control the heating temperature of pot 25 by heating coil 31.

[0032] Metal plate portion 48 has a groove portion that does not contact flange portion 32 over a portion of the circumferential range of flange portion 32 of pot 25. This groove portion extends from the upper end of pot accommodating portion 21 so as to be away from pot accommodating portion 21. This groove portion creates a gap between metal plate portion 48 and flange portion 32 of pot 25. This gap serves as a passage for discharging steam that is generated between pot accommodating portion 21 and pot 25 when pot 25 is heated with moisture adhering to its outer surface.

[0033] Hinge mechanism 27 includes hinge shaft 51 that swingably connects main body 23 and lid 26, and hinge spring 52 that applies a spring force to lid 26 so that lid 26, which closes pot housing section 21, opens upward on main body 23 around hinge shaft 51. Hinge shaft 51 is located near the upper part of the back surface of main body 23.

[0034] The planar shape of lid body 26 is a rectangle that covers main body 23. Lid body 26 defines the front, back, left side, right side, and top of rice cooker 1 above main body 23. Lid body 26 includes an outer lid 55 placed on the top of rice cooker 1, an outer lid cover 56 placed between outer lid 55 and main body 23, a metal heat sink 57 attached to outer lid cover 56, a lid heater 58 attached to heat sink 57, and an inner lid unit 59 detachably attached to outer lid cover 56 and detachably mounted below heat sink 57.

[0035] Outer lid 55 covers outer lid cover 56. When lid body 26 is closing main body 23, outer lid 55 covers and conceals outer lid cover 56 so that it is not exposed to the outside of rice cooker 1. Outer lid 55 has a recessed portion 55a that opens in a direction away from main body 23, in other words, that opens upward toward rice cooker 1, and a circuit board accommodating recess 55b provided within recessed portion 55a.

[0036] The outer lid cover 56 covers the main body 23 when the lid body 26 is closed on the main body 23.

[0037] The inner lid unit 59 comprises a metal inner lid 61 that is positioned below the heat sink 57 and in contact with the heat sink 57, a lid gasket 62 that is provided on the outer periphery of the inner lid 61, and a gasket base 63 that fixes the lid gasket 62 to the inner lid 61.

[0038] Heat sink 57 and inner lid 61 are formed from anodized aluminum or stainless steel plate material. Inner lid 61 corresponds to the bottom surface of lid body 26. Inner lid 61 has a disk shape with substantially the same diameter as the upper opening of pot 25.

[0039] Lid gasket 62 is, for example, a molded product made of silicone rubber or fluororubber. Lid gasket 62 is an annular sealing material that comes into contact with pot 25 and seals the gap between inner lid 61 and pot 25 when lid 26 is closed on main body 23. Lid gasket 62 comes into contact with the upper surface of flange 32 of pot 25 when lid 26 is closed.

[0040] When the lid body 26 with the inner lid unit 59 attached is closed, the lid gasket 62 contacts the flange portion 32 of the pot 25, and the inner lid unit 59 tightly covers the upper opening of the pot 25, sealing it so that steam generated when the pot 25 is heated does not leak between the pot 25 and the inner lid unit 59. For ease of explanation, the inside of the pot 25 closed by the inner lid unit 59 is referred to as the "pot internal space." The pot internal space is the space surrounded by the inner surface of the pot 25 and the bottom surface of the inner lid unit 59 and contains the food to be cooked. For ease of explanation, the pressure in the pot internal space will be referred to as the "internal pressure of the pot 25."

[0041] The lid heater 58 is, for example, a cord heater. The lid heater 58 heats the heat sink 57, thereby heating the inner lid 61 that is in contact with the heat sink 57.

[0042] The lid 26 also has a steam port 65 that is removably attached to the rear half of the upper surface of the lid 26 and discharges steam generated from the food being cooked in the pot 25 to the outside of the rice cooker 1, a steam exhaust path 66 that directs steam in the pot 25 to the steam port 65, and a pressure regulating valve 67 that allows or blocks the flow of gas in the steam exhaust path 66.

[0043] The steam discharge path 66 connects the steam port 65 and the pressure regulating valve 67. The steam discharge path 66 has an inlet-side labyrinth structure that is provided near the pressure regulating valve 67 and prevents steam from flowing linearly into the steam discharge path 66, and a discharge-side labyrinth structure that is provided near the steam port 65 and prevents steam from flowing linearly into the steam port 65.

[0044] Pressure regulating valve 67 is, for example, a solenoid valve. When pressure regulating valve 67 is opened, the inside of pot 25 is connected to the outside of rice cooker 1. At this time, pressure regulating valve 67 opens the inside of pot 25 to the atmosphere. Steam generated in pot 25 is released to the outside of rice cooker 1 through steam vent 65. When pressure regulating valve 67 is closed, the connection between the inside of pot 25 and the outside of rice cooker 1 is severed, restricting the flow of gas in and out through steam exhaust path 66. At this time, pressure regulating valve 67 seals the inside of pot 25. Steam generated in pot 25 increases the internal pressure of pot 25 above atmospheric pressure. The internal pressure of pot 25 can be reduced below atmospheric pressure by sucking out the gas inside pot 25 with pressure regulating valve 67 closed. The internal pressure of pot 25 can also be restored to atmospheric pressure by opening pressure regulating valve 67 while the internal pressure of pot 25 is reduced.

[0045] Pressure regulating valve 67 includes valve element 67a, which allows or blocks the flow of gas through steam exhaust passage 66, and valve element drive unit 67c, which includes solenoid 67b, which opens and closes valve element 67a. When steam in pot 25 is to be released to the outside of rice cooker 1, solenoid 67b moves valve element 67a in one direction to allow flow through steam exhaust passage 66. When the internal pressure of pot 25 is to be increased or decreased, solenoid 67b moves valve element 67a in the other direction to block flow through steam exhaust passage 66. When the food to be cooked in pot 25 boils, generating steam, and this steam fills pot 25, causing the internal pressure of pot 25 to exceed a predetermined value, valve element 67a is pushed up by the internal pressure of pot 25, opening steam exhaust passage 66. When the internal pressure of pot 25 falls below the predetermined value, valve element 67a closes steam exhaust passage 66. Such operation of valve body 67a maintains the internal pressure of pot 25 at or above atmospheric pressure.

[0046] Furthermore, the lid 26 is provided with a vacuum pump 68 that reduces the pressure inside the pot 25 when the lid 26 is closed.

[0047] The lid body 26 also includes a lid opening operation button 71 provided on the front half of the top surface of the lid body 26, a lid locking mechanism 72 that locks the opening and closing of the lid body 26, an operation panel 73 as an input / output device, and an input / output control circuit board 75 that controls the operation of the operation panel 73.

[0048] When lid-opening operation button 71 is operated, the lock between lid body 26, which closes pot accommodating section 21, and main body 23 is released. When lid body 26 and main body 23 are unlocked, the spring force of hinge spring 52 opens lid body 26 around hinge shaft 51 as the rotation center.

[0049] The lid locking mechanism 72 locks the lid 26 when the main body 23 is closed. The lid locking mechanism 72 unlocks the lid 26 in response to the operation of the lid-opening button 71. The lid locking mechanism 72 restricts the opening of the lid 26 even if the lid-opening button 71 is operated once if the internal pressure of the pot 25 is increased or decreased. If the lid-opening button 71 is operated again within a predetermined period of time, the lid locking mechanism 72 operates the pressure regulator valve 67 and the vacuum pump 68 to restore the internal pressure of the pot 25 to atmospheric pressure, and then releases the restriction on the opening of the lid 26. The lid locking operation of the lid locking mechanism 72 is controlled by the heating control circuit board 42. The detailed structure and control content of the lid locking mechanism 72 may be known technology, such as that described in JP 2015-171545 A. The lid locking operation of the lid locking mechanism 72 is not always performed. When the lid locking operation is not being performed, the lid 26 can be opened by operating the lid opening operation button 71 once.

[0050] Operation panel 73 is the top panel of lid 26 and rice cooker 1, and covers recessed portion 55a of outer lid 55. Operation panel 73 includes a display unit 76 that displays various information and an operation unit 77 that accepts various operations. Note that display unit 76 and operation unit 77 are essentially mounted on input / output control circuit board 75, and operation panel 73 includes a transparent window 73a that allows the display on display unit 76 to be seen through, and key tops 73b that correspond to a decorative panel that the user directly touches to operate operation unit 77.

[0051] The input / output control circuit board 75 is housed in the circuit board housing recess 55b of the outer lid 55 and is located directly below the operation panel 73. The input / output control circuit board 75 is equipped with a microprocessor, a memory device that stores digital information such as various calculation programs and parameters executed by the microprocessor, and a real-time clock (RTC) with a timekeeping function. The memory device stores various settings (arguments) related to multiple preset courses. The real-time clock functions as a clock that keeps track of the current time on the rice cooker 1 and as a timekeeping function. The real-time clock may be located on either the heating control circuit board 42 or the input / output control circuit board 75.

[0052] Display unit 76 is an output device that visually displays the current state of rice cooker 1. Display unit 76 is, for example, a display and a light-emitting diode (LED). The display is a liquid crystal display (LCD) panel or an organic electroluminescence (organic light-emitting diode) panel.

[0053] The operation unit 77 is an input device, a so-called touch sensor. The operation unit 77 is arranged directly above the display unit 76 so as to cover the display unit 76. The touch sensor has a plurality of key elements arranged on a plane. Each key element has a transparent electrode portion, for example, made of a conductive polymer, a contact portion connected to the input / output control circuit board 75, and pattern wiring connecting the transparent electrode portion and the contact portion. By pressing, touching, or bringing a fingertip against any of the display elements displayed on the display unit 76, the key element arranged directly above that display element is operated. The operation received by this key element is output to the input / output control circuit board 75 as a selection of the display element of the display unit 76 displayed directly below it.

[0054] A user of rice cooker 1 can select and input rice cooking conditions such as the type of rice, cooking method, hardness, and cooking time using operation unit 77. Based on the course set by operating operation unit 77, rice cooker 1 performs operations such as waiting for rice cooking, heating rice and water, keeping rice warm, and setting a timer for rice cooking.

[0055] It is assumed that a user of the rice cooker 1 will operate the operation panel 73 while standing in a position facing the front of the rice cooker 1. Therefore, the rice cooker 1 according to this embodiment is equipped with a lid-opening operation button 71 located in the front half of the top surface, closer to the user facing the front of the rice cooker 1, and a steam vent 65 located in the rear half of the top surface, farther from the user facing the front of the rice cooker 1. As a result, the rice cooker 1 according to this embodiment easily ensures a large space for arranging the display unit 76 between the lid-opening operation button 71 and the steam vent 65, and the size of the operation unit 77 located directly above the display unit 76 can be set as large as possible. Therefore, the rice cooker 1 can achieve high visibility of the display unit 76, high operability of the operation unit 77, and high safety against steam emitted from the steam vent 65.

[0056] Furthermore, the rice cooker 1 according to this embodiment does not have the physical operation keys found in conventional rice cookers, such as a rice cooker key and an off key, and can be operated using only the operation unit 77. Therefore, the rice cooker 1 according to this embodiment eliminates the need to search for the operation keys and provides intuitive operability. Furthermore, the rice cooker 1 without physical operation keys can integrate the display unit 76 and operation unit 77, improving space utilization efficiency and making it easier to design a much sleek exterior compared to conventional rice cookers in which the input and output devices are separated. Furthermore, the top surface of the rice cooker 1, which does not have physical operation keys, can be made flat with almost no irregularities or gently curved. The shape of the top surface of this rice cooker 1 makes it easy to clean, such as by wiping.

[0057] FIG. 3 is a cross-sectional view of the inner frame and heating coil of the rice cooker according to this embodiment.

[0058] FIG. 4 is a bottom view of the inner frame and heating coil of the rice cooker according to this embodiment.

[0059] As shown in FIGS. 3 and 4, the heating coil 31 of the rice cooker 1 according to this embodiment includes a plurality of coils 31u and 31d.

[0060] First coil 31u is provided on the outer surface of inner frame 37, and second coil 31d is provided on the outer bottom surface of inner frame 37. First coil 31u faces the lower part of the outer surface of pot 25 across inner frame 37. Second coil 31d faces the outer bottom surface of pot 25 across inner frame 37.

[0061] The transfer of heat when the heating coil 31 is energized will be described.

[0062] When the first coil 31u is energized, the lower portion of the outer surface of the pot 25 first heats up, and the heat from this portion is conducted to the main material 25a of the pot 25 and transferred to the water contained in the food that is in contact with the lower portion of the inner surface of the pot 25. Heat transfer within the food occurs primarily through water movement, i.e., convection. Where rice is present in the food, water movement is limited to the narrow gaps between the rice grains, slowing the movement of water and heat. Where rice is not present, the movement of water and heat, i.e., convection, becomes active. Therefore, after the water in contact with the lower portion of the inner surface, the water in the upper portion of the food first heats up. Because the rice grains sink to the bottom of the pot 25 due to their own weight, the upper portion of the food contains almost no rice grains and essentially only water. Subsequently, in the center of the food, the water and heat from the upper portion, which has become hot, move to the middle portion of the food, which is still cooler, and then to the lower portion of the food. This phenomenon is so-called thermal convection, and is called "external convection" due to the first coil 31u.

[0063] Furthermore, when second coil 31d is energized, the outer surface of the bottom of pot 25 heats up first, and the heat from this area is conducted to main material 25a of pot 25 and transferred to the inner surface of the bottom of pot 25, i.e., the water contained in the lower portion of the food that is in contact with the bottom. Because the rice grains sink to the bottom of pot 25 due to their own weight, the bottom of the pot is covered with rice and water contained in the lower portion of the food. Therefore, the heat from the bottom of the pot increases the temperature and pressure of the water covering the bottom of the pot. Then, the water at the bottom of the pot, whose temperature and pressure have increased, moves upward through the gaps between the rice grains contained in the food. In other words, the water heated in the lower portion of the food, i.e., the hot water, moves together with the heat to the middle portion of the food, and then to the upper portion of the food. This phenomenon is known as "blowing up" and is called "internal convection" caused by second coil 31d.

[0064] When current is alternately applied to first coil 31u and second coil 31d, external convection and internal convection alternately occur in the food to be cooked in pot 25. In other words, when current is alternately applied to first coil 31u and second coil 31d, the alternating external and internal convection promotes stirring of the water contained in the food to be cooked in pot 25, thereby reducing uneven heating of the food to be cooked.

[0065] The heating control circuit board 42 of the rice cooker 1 according to this embodiment operates the heating coil 31 in a plurality of current patterns that combine various current-carrying times of the first coil 31u, the second coil 31d, the output of the first coil 31u, and the output of the second coil 31d. These multiple current patterns are stored in the memory unit.

[0066] One type of energization pattern includes energizing the first coil 31u with a first output W1 and a first energization time T1, and then energizing the second coil 31d with a second output W2 and a second energization time T2. Each energization time T1 and T2 is preferably several seconds or longer. This allows external and internal convection to alternately occur in the food being cooked in the pot 25 for a predetermined period of time or longer. The alternating occurrence of external and internal convection promotes agitation of the water in the food being cooked in the pot 25 and reduces uneven heating.

[0067] It is preferable that the first current application time T1 and the second current application time T2 are different from each other. In other words, it is preferable that the time during which external convection occurs is different from the time during which internal convection occurs in a certain current application type.

[0068] The energization type may include one in which either the energization time or output of the heating coil 31 is varied while the other is kept constant. The energization time of each coil 31, 31d may be constant while the output of each coil 31, 31d may be different. Alternatively, the output of each coil 31, 31d may be constant while the energization time of each coil 31, 31d may be different.

[0069] The multiple energization patterns may include a de-energization period during which all of the heating coils 31 are de-energized. That is, the energization pattern is such that one of the two coils 31, 31d is energized for a predetermined energization time and with a predetermined output, and then, after a first de-energization period has elapsed, the other of the two coils 31, 31d is energized for a predetermined energization time and with a predetermined output, and then a second de-energization period is awaited. The first de-energization period and the second de-energization period may be the same or different.

[0070] The energization pattern may also include one in which current is intermittently applied to only one of the two coils 31, 31d, and no current is applied to the other of the two coils 31, 31d (no current is applied). Such an energization pattern applies current to one of the two coils 31, 31d for a predetermined current application time and at a predetermined current output, and does not apply current to both of the two coils 31, 31d for the predetermined current application time. Such an energization pattern is suitable for a heat retention process.

[0071] These current application patterns are repeated for a predetermined time or a predetermined number of times.

[0072] When the energization type is switched, the first energization type switches from energizing the first coil 31u with a first output W1 and a first energization time T1, and then energizing the second coil 31d with a second output W2 and a second energization time T2, to energizing the first coil 31u with a third output W3 and a third energization time T3, and then energizing the second coil 31d with a fourth output W4 and a fourth energization time T4. Each energization type is repeatedly executed for a predetermined time or a predetermined number of times before and after the switching.

[0073] The content of each energization type and the combination of multiple energization types are suitably set for each process included in the course.

[0074] In the energization type, the output of the first coil 31u and the output of the second coil 31d are adjusted by, for example, PWM control (Pulse Width Modulation).

[0075] Next, the lid 26 will be described in detail.

[0076] FIG. 5 is an exploded perspective view of the rice cooker according to this embodiment, showing a state in which the operation panel of the lid body has been removed.

[0077] FIG. 6 is a plan view of the outer lid of the rice cooker according to this embodiment.

[0078] FIG. 7 is an enlarged cross-sectional view of the outer lid of the rice cooker according to this embodiment, taken along a plane that crosses the circuit board accommodating recess in the width direction of the rice cooker.

[0079] As shown in Figures 5 and 6, the lid 26 of the rice cooker 1 according to this embodiment includes an outer lid 55 having a recessed portion 55a that opens away from the main body 23 and that covers the outer lid cover 56, and an operation panel 73 as a top panel that covers the recessed portion 55a. A small gap is formed between the operation panel 73 and the outer lid 55, which is a component adjacent to the operation panel 73. This gap is not large enough to allow a liquid, such as water, which is abundant in a kitchen where the rice cooker 1 is likely to be installed, to flow forcefully into the lid 26. However, there is room for liquid to seep into the interior of the lid 26 through the gap between the operation panel 73 and the outer lid 55 due to capillary action.

[0080] 5 and 6, outer lid 55 of lid body 26 according to this embodiment has drain groove 82 provided along at least a portion of the edge of recessed portion 55a. When liquid seeps into recessed portion 55a through the gap between operation panel 73 and outer lid 55, drain groove 82 guides the liquid to hole 81, which allows the liquid to flow into the space defined by outer lid 55 and outer lid cover 56. Drain groove 82 captures the liquid that has seeped into the interior of lid body 26 through the gap between operation panel 73 and outer lid 55 before it flows toward the center of recessed portion 55a, and allows the liquid to flow out through hole 81 into the space defined by outer lid 55 and outer lid cover 56.

[0081] In recent years, there has been an increasing demand for a smaller rice cooker 1 in terms of installation volume, while there has also been an increasing demand for larger display characters in terms of visibility of display unit 76 and for larger key tops 73b in terms of operability of operation unit 77. In other words, while there is a demand for a smaller lid body 26, there is a demand for a larger input / output control circuit board 75. As a result, the proportion of circuit board accommodating recess 55b in recess 55a of outer lid 55 increases, and the edges of recess 55a and circuit board accommodating recess 55b tend to get closer to each other.

[0082] If liquid seeps into recessed portion 55a through the gap between operation panel 73 and outer lid 55, the liquid may flow into circuit board accommodating recess 55b, which is located near the edge of recessed portion 55a. Circuit board accommodating recess 55b accommodates input / output control circuit board 75, which is equipped with operation unit 77 serving as an input device and display unit 76 serving as a display device. Therefore, if liquid flows into circuit board accommodating recess 55b, it may cause a malfunction of input / output control circuit board 75 accommodated in circuit board accommodating recess 55b.

[0083] Therefore, drain groove 82 is laid at least along the area where circuit board accommodating recess 55b and recessed portion 55a are close to each other. For convenience, the portion of drain groove 82 that is laid along the area where circuit board accommodating recess 55b and recessed portion 55a are close to each other is referred to as the "narrow portion drain groove 82a," and the rest of drain groove 82 excluding narrow portion drain groove 82a is referred to as the "non-narrow portion drain groove 82b." Narrow portion drain groove 82a extends in the front-to-rear direction of rice cooker 1 along the left and right sides of circuit board accommodating recess 55b.

[0084] It is preferable to have a plurality of holes 81. The plurality of holes 81 can promote the discharge of the liquid captured by the drain groove 82 over a wide area of ​​the drain groove 82.

[0085] The holes 81 include a plurality of side drainage holes 81a provided in narrow portion drainage groove 82a of drainage groove 82 and a plurality of front drainage holes 81b arranged on the front edge of recessed portion 55a. In other words, the holes 81 include at least a plurality of side drainage holes 81a arranged in a location where circuit board accommodating recess 55b and recessed portion 55a are close to each other.

[0086] The multiple side drainage holes 81a allow liquid captured by the narrow portion drainage groove 82a and liquid captured by the non-narrow portion drainage groove 82b and flowing into the narrow portion drainage groove 82a to quickly flow out onto the top surface of the outer lid cover 56, reliably preventing liquid from overflowing into the circuit board accommodating recess 55b.

[0087] The front drain hole 81b is located near the lid lock mechanism 72. The liquid drained from the front drain hole 81b enters the lid body 26 through the gap between the lid opening operation button 71 and the opening 73c of the operation panel 73 where the lid opening operation button 71 is exposed, and passes near the lid lock mechanism 72 to join the liquid received by the outer lid cover 56. A known technique such as that described in JP 2023-151879 A may be applied as a structure for discharging the joined liquid outside the machine.

[0088] The left and right edges of circuit board accommodating recess 55b are close to the left and right edges of recessed portion 55a, while the front edge of circuit board accommodating recess 55b is spaced apart from the front edge of recessed portion 55a and the rear edge of circuit board accommodating recess 55b is spaced apart from the rear edge of recessed portion 55a. Narrow portion drainage grooves 82a are located between the left and right edges of circuit board accommodating recess 55b and the left and right edges of recessed portion 55a. Non-narrow portion drainage grooves 82b are located along the front edge and rear edge of recessed portion 55a.

[0089] Drainage groove 82 may be provided along the entire periphery of the edge of recessed portion 55a. Multiple holes 81 may be provided discretely over the entire length of drainage groove 82, including narrow portion drainage groove 82a.

[0090] When the lid 26 is closing the main body 23, the entire drain groove 82 is inclined downward from the rear side to the front side of the rice cooker 1. Liquid that flows into the narrow portion drain groove 82a quickly flows out through the side drain holes 81a to the top surface of the outer lid cover 56, which serves as a drain pan. Liquid that flows into the drain groove 82 other than the narrow portion drain groove 82a is captured by the drain groove 82 and spreads along the drain groove 82 according to the amount of liquid. Liquid captured in the portion of the drain groove 82 rearward of the narrow portion drain groove 82a flows out to the top surface of the outer lid cover 56 when it reaches the side drain hole 81a. Liquid captured in the portion of the drain groove 82 forward of the narrow portion drain groove 82a flows out to the top surface of the outer lid cover 56 when it reaches the front drain hole 81b. The structure for discharging the liquid that has flowed onto the upper surface of the outer lid cover 56 to the outside of the device can be realized by applying a known technique such as that described in Japanese Patent Application Laid-Open No. 2023-141040.

[0091] FIG. 8 is an enlarged cross-sectional view of the outer lid of the rice cooker according to this embodiment, taken along the drain groove.

[0092] 5 and 6, and as shown in Fig. 8, the depth of narrow portion drainage groove 82a of lid 26 according to this embodiment is deeper than the depth of non-narrow portion drainage groove 82b. Narrow portion drainage groove 82a, like a deep moat, can prevent liquid captured by narrow portion drainage groove 82a and liquid captured by non-narrow portion drainage groove 82b and flowing into narrow portion drainage groove 82a from overflowing into circuit board accommodating recess 55b.

[0093] Furthermore, the front and rear edges of circuit board accommodating recess 55b are farther apart from the front and rear edges of recessed portion 55a than the left and right edges of circuit board accommodating recess 55b and the left and right edges of recessed portion 55a, so even if liquid overflows from non-narrow portion drainage groove 82b, the liquid will not immediately flow into circuit board accommodating recess 55b. Furthermore, it is difficult to imagine that a large amount of liquid that overflows from non-narrow portion drainage groove 82b and reaches circuit board accommodating recess 55b will flow into the interior of lid body 26 through the gap between operation panel 73 and outer lid 55.

[0094] Outer lid 55 has a rib 83 that is disposed above side drainage hole 81a and spans drainage groove 82. Because the left and right edges of circuit board accommodating recess 55b and the left and right edges of recessed portion 55a are close to each other, when outer lid 55 is molded from synthetic resin, providing side drainage hole 81a in outer lid 55 poses a molding risk in that the decorative surface of outer lid 55, which corresponds to the bank that defines recessed portion 55a, will collapse into recessed portion 55a. Therefore, by bridging rib 83 above side drainage hole 81a, outer lid 55 can be molded as intended.

[0095] The rice cooker 1 according to the present embodiment configured as described above is provided with a drain groove 82 that is provided along at least a portion of the edge of the recessed portion 55a and that, if liquid seeps into the recessed portion 55a through the gap between the operation panel 73 and the outer lid 55, guides the liquid to a hole 81 that allows the liquid to flow into the space defined by the outer lid 55 and the outer lid cover 56. Therefore, in the rice cooker 1, the drain groove 82 captures any liquid that has seeped into the inside of the lid body 26 through the gap between the operation panel 73 and the outer lid 55 before it flows toward the center of the recessed portion 55a, and allows the liquid to flow out through the hole 81 into the space defined by the outer lid 55 and the outer lid cover 56.

[0096] Furthermore, the rice cooker 1 according to this embodiment has a plurality of holes 81 provided in the drain groove 82. Therefore, the rice cooker 1 can promote the discharge of liquid captured by the drain groove 82 over a wide area of ​​the drain groove 82.

[0097] Furthermore, rice cooker 1 according to this embodiment is provided with rib 83 that is positioned above hole 81 and spans drain groove 82. Therefore, even if rice cooker 1 has side drain hole 81a provided in outer lid 55, which is a molded synthetic resin product, the design surface of outer lid 55, which corresponds to the bank that defines recessed portion 55a, is prevented from collapsing into recessed portion 55a, and outer lid 55 can be provided with an intended design surface.

[0098] Furthermore, rice cooker 1 according to this embodiment is provided with drainage groove 82, i.e., narrow portion drainage groove 82a, laid along at least the area where circuit board accommodating recess 55b and recessed portion 55a are close to each other. As a result, rice cooker 1 can simultaneously satisfy the demands for compactness of rice cooker 1, improved visibility of display unit 76, and improved operability of operation unit 77, while reliably preventing breakdown of input / output control circuit board 75, which is expected to be large, due to liquids such as water.

[0099] Furthermore, rice cooker 1 according to this embodiment is provided with hole 81, i.e., side drain hole 81a, located at least where circuit board accommodating recess 55b and recessed portion 55a are close to each other. As a result, rice cooker 1 can very quickly drain liquid captured by narrow portion drain groove 82a into the space defined by outer lid 55 and outer lid cover 56, reliably preventing breakdown of input / output control circuit board 75.

[0100] Therefore, the rice cooker 1 according to the present invention can smoothly drain any liquid that enters the inside of the lid body 26 through the gap between the operation panel 73, which corresponds to the top plate of the lid body 26, and the outer lid 55, which is its adjacent member.

[0101] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0102] 1...rice cooker, 21...pot accommodating section, 23...main body, 25...pot, 25a...main material, 25b...heating element, 26...lid body, 27...hinge mechanism, 31...heating coil, 31u...first coil, 31d...second coil, 32...flange section, 35...bottom plate, 36...upper frame, 37...inner frame, 37a...temperature sensor placement hole, 38...outer frame, 39...controller accommodating chamber, 41...vent, 42...heating control circuit board, 43...heat sink, 45...cooling fan, 46...pot temperature sensor, 48...metal plate section, 51...hinge shaft, 52...hinge spring, 55...outer lid, 55a...recessed section, 55b...circuit board accommodating recess, 56...outer lid cover, 57...heat sink, 58 ... Lid heater, 59... inner lid unit, 61... inner lid, 62... lid gasket, 63... gasket base, 65... steam vent, 66... ​​steam exhaust path, 67... pressure regulating valve, 67a... valve body, 67b... solenoid, 67c... valve body drive unit, 68... pressure reducing pump, 69... pressure reducing hole, 70... pressure reducing valve, 71... lid opening operation button, 72... lid lock mechanism, 73... operation panel, 73a... transparent window, 73b... key top, 73c... opening, 75... input / output control circuit board, 76... display unit, 77... operation unit, 81... hole, 81a... side drain hole, 81b... front drain hole, 82... drain groove, 82a... narrow section drain groove, 82b... non-narrow section drain groove, 83... rib.

Claims

1. A pot capable of accommodating food to be cooked; a main body having a pot accommodating portion capable of accommodating the pot; a lid that can open and close the pot storage section, The lid body is an outer lid cover that covers the main body when the lid body is closed; an outer lid having a recessed portion that opens in a direction away from the main body and that covers the outer lid cover; an upper panel that covers the recessed portion, The outer lid has a drain groove along at least a portion of the edge of the recessed portion, which, if liquid seeps into the recessed portion through the gap between the top panel and the outer lid, directs the liquid to a hole through which the liquid flows into the space partitioned by the outer lid and the outer lid cover.

2. The rice cooker according to claim 1 , wherein a plurality of holes are provided in the drain groove.

3. The rice cooker according to claim 1 or 2, further comprising a rib disposed above the hole and spanning the drain groove.

4. the outer cover has a circuit board accommodating recess provided in the recessed portion for accommodating an input / output control circuit board on which an input device and a display device are mounted, the top panel has an operation unit of the input device and a transparent window through which a display of the display device is transmitted; 3. The rice cooker according to claim 1, wherein the drain groove is provided along at least a portion where the circuit board receiving recess and the recessed portion are close to each other.

5. The rice cooker according to claim 4, wherein the hole is disposed at least in a location where the circuit board accommodating recess and the recessed portion are close to each other.

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