Electric cooker

Abstract

The invention provides a rice cooker capable of smoothly discharging liquid which is immersed into a cover body from a gap between a panel corresponding to a top plate of the cover body and an adjacent component. A rice cooker (1) is provided with: a pot capable of accommodating an object to be cooked; a main body provided with a pot accommodating part capable of accommodating the pot; and a cover body capable of opening and closing the pot accommodating part, the cover body being provided with: an outer cover which is covered on the main body in a state in which the cover body closes the main body; an outer cover that has a recessed portion that is open in a direction away from the main body, and that is covered by the outer cover cover; and an operation panel as an upper surface panel covered on the recess portion, the outer cover has a drainage groove provided along at least a part of an edge of the recess portion, and when liquid passes through a gap between the operation panel and the outer cover and enters the recess portion, the liquid is guided to a hole through which the liquid flows out by the drainage groove. Wherein the hole is used for enabling the liquid to flow out towards the space divided by the outer cover and the outer cover cover.

Description

Technical Field

[0001] This invention relates to an electric rice cooker. Background Technology

[0002] A well-known rice cooker includes: a pot for holding rice, a main body with a pot housing, a lid for opening and closing the pot housing, a hinge mechanism connecting the lid to the main body, and a locking mechanism for locking the lid when the main body is closed. The lid includes: an outer cover corresponding to the bottom plate and a panel corresponding to the top plate. The locking mechanism includes: a lid operating body for releasing the lock. The lid operating body passes through the inside and outside of the lid via an opening or hole provided on the lid panel. When the lid operating body is pressed, the lock of the locking mechanism is released.

[0003] When liquid, such as water, overflows onto the upper surface of the lid, it seeps into the interior of the lid through a small gap between the opening between the lid's operating body and the panel. The liquid that seeps into the lid is caught by an outer cover, which is equivalent to the bottom plate of the lid, and is then drained out of the rice cooker through the outer cover. In other words, the outer cover functions as a drain tray.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2023-151879 Summary of the Invention

[0007] Sometimes the cover panel has: an external surface for touch keys as an input device, or a viewing window for a display device. In such cases, a circuit board for mounting the input device or display device may be housed within the cover. Such a cover may have a slight gap between the component having a circuit board housing for accommodating components adjacent to the panel, such as a circuit board, and the panel itself.

[0008] Even liquid that seeps into the lid body from the gap between the component adjacent to the panel and the panel, just like liquid that seeps into the lid body from the gap between the lid body operating body and the lid body opening, requires the lid body to drain it out of the pot.

[0009] Therefore, the object of the present invention is to provide a rice cooker that can smoothly drain liquid that has entered into the body of the lid from the gap between the panel corresponding to the top plate and its adjacent parts.

[0010] To address the aforementioned problem, the rice cooker according to embodiments of the present invention comprises: a pot capable of containing food to be cooked; a main body having a pot receiving portion capable of containing the pot; and a lid capable of opening and closing the pot receiving portion. The lid comprises: an outer cover covering the main body when the lid is closed; an outer cover having a recessed portion opening away from the main body and being covered by the outer cover; and an upper surface panel covering the recessed portion. The outer cover has a drainage groove provided along at least a portion of the edge of the recessed portion. When liquid seeps into the recessed portion through the gap between the upper surface panel and the outer cover, the drainage groove guides the liquid toward the space defined by the outer cover and the outer cover, thereby directing the liquid toward the outlet hole.

[0011] The effects of the invention

[0012] According to the above configuration, liquid that has entered the body of the cover body from the gap between the panel corresponding to the top plate and its adjacent parts can be smoothly drained. Attached Figure Description

[0013] Figure 1 This is a perspective view of the rice cooker according to an embodiment of the present invention.

[0014] Figure 2 This is a longitudinal cross-sectional view of the rice cooker according to an embodiment of the present invention.

[0015] Figure 3 This is a cross-sectional view of the inner frame and heating coil of the rice cooker involved in this embodiment.

[0016] Figure 4 This is a bottom view of the inner frame and heating coil of the rice cooker according to this embodiment.

[0017] Figure 5 This is an exploded perspective view of the rice cooker according to this embodiment, and it shows the state of the operation panel with the lid removed.

[0018] Figure 6 This is a plan view of the outer lid of the rice cooker according to this embodiment.

[0019] Figure 7 This is an enlarged cross-sectional view of the outer cover of the rice cooker according to this embodiment, and a cross-sectional view of the surface that runs through the circuit board receiving recess in the width direction of the rice cooker.

[0020] Figure 8 This is an enlarged cross-sectional view of the outer lid of the rice cooker according to this embodiment, and it is a cross-sectional view along the drain groove.

[0021] Explanation of reference numerals in the attached figures

[0022] 1… Rice cooker; 21… Pot housing; 23… Main body; 25… Pot; 25a… Main material; 25b… Heating element; 26… Lid; 27… Hinging mechanism; 31… Heating coil; 31u… First coil; 31d… Second coil; 32… Flange; 35… Base plate; 36… Top frame; 37… Inner frame; 37a… Temperature sensor mounting hole; 38… Outer frame; 39… Control unit housing; 41… Vent; 42… Heating control circuit board; 43… Radiator; 45… Cooling fan; 46… Pot temperature sensor; 48… Metal plate; 51… Hinge shaft; 52… Hinge spring; 55… Outer cover; 55a… Recess; 55b… Circuit board housing recess; 56… Outer cover; 57… Heat sink; 5 8…Lid heater; 59…Inner cover unit; 61…Inner cover; 62…Lid gasket; 63…Gasket base; 65…Steam port; 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 locking mechanism; 73…Operation panel; 73a…View 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. Detailed Implementation

[0023] Below, refer to Figures 1 to 8 This illustrates the rice cooker according to the present invention. Furthermore, in several accompanying drawings, the same or equivalent components are given the same reference numerals.

[0024] Figure 1 This is a perspective view of the rice cooker according to an embodiment of the present invention.

[0025] Figure 2 This is a longitudinal cross-sectional view of the rice cooker according to an embodiment of the present invention.

[0026] in addition, Figure 1 This is a perspective view of the rice cooker 1 as seen from the upper right front of the rice cooker 1 according to this embodiment. That is, Figure 2 The front, right side, and top surface of the rice cooker 1 are not visible, nor are the back, left side, and bottom.

[0027] like Figure 1 as well as Figure 2As shown, the rice cooker 1 according to this embodiment includes: a rectangular body 23 having a pot receiving portion 21 that is open at the top; a pot 25 housed in the pot receiving portion 21; a lid 26 covering the upper surface of the body 23 and closing the pot receiving portion 21 in an openable and closable manner; a hinge mechanism 27 supporting the lid 26 to the body 23 in an openable and closable manner; and a power cord capable of being connected to an external power source, such as a commercial AC power outlet. When the lid 26 is opened towards the top of the body 23, the pot 25 can be removed from the pot receiving portion 21.

[0028] The rice cooker 1 uses a heating coil 31 to heat the rice and water contained in the pot 25 to cook the rice, and then uses the heating coil 31 to keep the cooked rice warm. The rice cooker 1 selects a cooking cycle from multiple cooking cycles to cook the rice.

[0029] Each rice cooking cycle includes the following cooking conditions: rice type, cooking method, desired firmness of cooked rice, and cooking time. Each rice cooking cycle must contain at least two of these cooking conditions.

[0030] Each cooking cycle involves heating the rice inside the pot 25 by pressurizing it to a predetermined pressure. Each cooking cycle includes a process set according to the brand of rice or the rice polishing ratio. These processes include, for example, a soaking cooking process to promote water absorption by the rice added to the pot 25, a boiling heating process to quickly raise the temperature of the rice to its boiling point, a continuous boiling process to maintain the boiling of the rice, and a steaming process to maintain a high temperature that prevents the rice from burning. The rice cooker 1 can also perform a keep-warm process separately from the cooking cycle, or continue the cooking cycle while performing a keep-warm process to maintain the rice in the pot 25 at a predetermined keep-warm temperature.

[0031] Rice cooker 1 can also perform a cooking cycle that heats food other than rice contained in pot 25 using a predetermined heating mode. Unless otherwise specified, the food to be cooked includes rice. Additionally, rice cooker 1 can perform a maintenance cycle by boiling the water contained in pot 25, where steam is used inside rice cooker 1 to float hard-to-maintain parts to the surface or to remove odors. Hereinafter, for ease of explanation, the cooking cycle, the food preparation cycle, and the maintenance cycle will all be referred to simply as "cycle".

[0032] The pot 25 is also called a "cauldron". The pot 25 is a bottomed container capable of holding water or rice for cooking. The pot 25 has: a main body 25a made of aluminum with high heat transfer properties, and a heating element 25b joined to the main body by covering the bottom surface from the lower part of its outer periphery. The heating element is made of, for example, a magnetic metal plate made of ferritic stainless steel. The inner side of the pot 25 has a fluoropolymer coating. The fluoropolymer coating is, for example, made of polytetrafluoroethylene (PTFE) or perfluoroalkoxy alkane (PFA). The pot 25 has: a flange 32 that protrudes radially outward and surrounds the entire circumference of its outer periphery.

[0033] The pot 25 has a flange 32 that protrudes radially outward and surrounds the entire circumference of the outer peripheral surface.

[0034] The main body 23 has a rectangular shape. The main body 23 defines the front, back, left side, right side, and bottom of the rice cooker 1 below the lid 26. The main body 23 includes: a bottom plate 35 defining the bottom of the main body 23; an upper frame 36 covering the bottom plate 35 and defining a portion of the upper surface and sides of the main body 23; a bowl-shaped inner frame 37 integrally formed on the upper frame 36; and an outer frame 38 defining the remainder of the upper surface of the main body 23.

[0035] The base plate 35, the upper frame 36, and the outer frame 38 form the outer outline of the main body 23. The base plate 35 and the upper frame 36 are molded products made of synthetic resin, such as polypropylene (PP). The outer frame 38 is a molded product made of metal material, such as stainless steel.

[0036] The upper frame 36 and the inner frame 37 define the pot receiving section 21. The inner frame 37 corresponds to the bottom plate of the pot receiving section 21. The inner frame 37 is, for example, a machined product of aluminized steel sheet.

[0037] Regarding the pot housing 21, its upper edge contacts the lower surface of the flange 32 of the pot 25, and the pot 25 is housed within the pot housing 21 in a suspended state. With the pot 25 housed in the pot housing 21, the flange 32 of the pot 25 contacts the upper edge of the pot housing 21 with almost no gap. However, a portion of the circumferential area of ​​the flange 32 of the pot 25 has a non-contact area. This area is defined as a groove extending from the upper end of the pot housing 21, separating from it. This groove creates a gap between the pot housing 21 and the flange 32 of the pot 25. When the pot 25 is heated while moisture adheres to its outer surface, this gap serves as a passage for the release of steam generated between the pot housing 21 and the pot 25.

[0038] Additionally, the main body 23 has a control compartment 39 that is planned between its outer contour and the pot housing 21. The outer contour of the main body 23 has a vent 41 that introduces outside air into the control compartment 39. The vent 41 is preferably located on the bottom or side of the main body 23.

[0039] Furthermore, the main body 23 includes a heating control circuit board 42 housed in the control unit housing 39. The heating control circuit board 42 includes a storage device for storing the microprocessor and various digital information such as calculation programs and parameters executed by the microprocessor. The storage device stores various settings (parameters) associated with multiple preset processes.

[0040] In addition, the main body 23 includes: a heat sink 43 for the microprocessor mounted on the heating control circuit board 42, and a cooling fan 45 that blows air toward the heat sink 43.

[0041] The heat sink 43 is made of a material with good heat transfer properties, such as aluminum. The cooling fan 45 is positioned below or to the side of the heat sink 43. The cooling performance achieved by combining the heat sink 43 and the cooling fan 45 is designed to maintain the microprocessor's temperature within its operating range. The cooling fan 45 and the vent 41 of the main body 23 are preferably configured to sandwich the pot 25. This configuration contributes to the miniaturization of the product.

[0042] In addition, the main body 23 includes a heating coil 31 disposed on the outer surface of the inner frame 37, and a pot temperature sensor 46 disposed at the center of the bottom surface of the inner frame 37 and for monitoring the temperature of the bottom of the pot 25.

[0043] The heating coil 31 is configured to face the lower part of the outer peripheral surface and the bottom surface of the pot 25 housed in the pot housing 21. The heating coil 31 generates an alternating magnetic field to electromagnetically induction heat the heating element 25b of the pot 25.

[0044] The pot temperature sensor 46 passes through the temperature sensor mounting hole 37a in the center of the bottom surface of the inner frame 37 and contacts the bottom surface of the pot 25. The pot temperature sensor 46 has a thermistor for monitoring the bottom temperature of the pot 25. Hereinafter, the temperature of the bottom of the pot 25 will also be referred to as the "bottom temperature". The pot temperature sensor 46 is pressed against the bottom surface of the pot 25 by spring force. The bottom temperature detected by the pot temperature sensor 46 is specifically used for managing the heating temperature of the pot 25 heated by the heating coil 31.

[0045] Furthermore, the metal plate portion 48 has a groove in a portion of the circumferential direction of the flange portion 32 of the pot 25 that is not in contact with the flange portion 32. This groove extends from the upper end of the pot housing portion 21, separating it from the pot housing portion 21. This groove creates a gap between the metal plate portion 48 and the flange portion 32 of the pot 25. When the pot 25 is heated while moisture adheres to its outer surface, this gap serves as a passage for the steam generated between the pot housing portion 21 and the pot 25 to escape.

[0046] The hinge mechanism 27 includes: a hinge shaft 51 that connects the main body 23 and the lid 26 in a swingable manner, and a hinge spring 52 that applies a spring force to the lid 26 so that it is lifted upward toward the main body 23 with the hinge shaft 51 as the lid is used to close the pot receiving part 21. The hinge shaft 51 is located next to the upper part of the back of the main body 23.

[0047] The lid 26 has a rectangular shape that covers the main body 23. The lid 26 defines the front, back, left side, right side, and top surface of the rice cooker 1 above the main body 23. The lid 26 includes: an outer cover 55 disposed on the top of the rice cooker 1, an outer cover cover 56 disposed between the outer cover 55 and the main body 23, a metal heat sink 57 disposed on the outer cover cover 56, a lid heater 58 disposed on the heat sink 57, and an inner cover unit 59 that is detachably mounted on the outer cover cover 56 and detachably fitted below the heat sink 57.

[0048] The outer cover 55 is covered by the outer cover 56. When the cover 26 is closed to the main body 23, the outer cover 55 conceals the outer cover 56, preventing it from being visible from the rice cooker 1. The outer cover 55 has: a recess 55a that opens away from the main body 23, in other words, opening towards the top of the rice cooker 1; and a circuit board receiving recess 55b disposed within the recess 55a.

[0049] The outer cover 56 is covered by the main body 23 when the cover 26 is closed.

[0050] The inner cover unit 59 includes: a metal inner cover 61 disposed below and in contact with the heat sink 57, a cover gasket 62 disposed on the outer periphery of the inner cover 61, and a gasket base 63 for fixing the cover gasket 62 to the inner cover 61.

[0051] The heat sink 57 and the inner cover 61 are molded products of anodized aluminum sheet or stainless steel sheet. The inner cover 61 corresponds to the bottom surface of the cover body 26. The inner cover 61 has a disc shape with a diameter substantially the same as the upper opening of the pot 25.

[0052] The cover gasket 62 is, for example, a molded product of silicone rubber or fluororubber. The cover gasket 62 is an annular sealing material that contacts the pot 25 and seals the gap between the inner cover 61 and the pot 25 when the cover 26 is closed. The cover gasket 62 contacts the upper surface of the flange 32 of the pot 25 when the cover 26 is closed.

[0053] When the lid 26, with the inner lid unit 59 installed, is closed, the lid gasket 62 contacts the flange 32 of the pot 25. The inner lid unit 59 completely covers the upper opening of the pot 25 without gaps, sealing it so that steam generated when the pot 25 is heated will not leak out between the pot 25 and the inner lid unit 59. For ease of explanation, the inside of the pot 25, which is closed by the inner lid unit 59, is referred to as the "pot interior space". The pot interior space is the space enclosed by the inner surface of the pot 25 and the bottom surface of the inner lid unit 59, which contains the food being cooked. Furthermore, for ease of explanation, the pressure in the pot interior space will be referred to as the "internal pressure of the pot 25" below.

[0054] The cover heater 58 is, for example, a wire heater. The cover heater 58 heats the inner cover 61, which is in contact with the heat sink 57, by heating the heat sink 57.

[0055] In addition, the lid 26 includes: a steam vent 65, which is detachably mounted on the rear half of the upper surface of the lid 26 and discharges steam generated from the cooked food in the pot 25 to the outside of the rice cooker 1; a steam discharge path 66, which guides the steam in the pot 25 toward the steam vent 65; and a pressure regulating valve 67, which allows or cuts off the flow of gas in the steam discharge path 66.

[0056] Steam discharge path 66 connects steam port 65 and pressure regulating valve 67. Steam discharge path 66 has: an inflow-side labyrinth structure provided next to pressure regulating valve 67 to prevent steam from flowing into steam discharge path 66 in a straight line, and an outlet-side labyrinth structure provided next to steam port 65 to prevent steam from flowing into steam port 65 in a straight line.

[0057] The pressure regulating valve 67 is, for example, a solenoid valve. When the pressure regulating valve 67 is opened, the inside of the pot 25 and the outside of the rice cooker 1 are connected. At this time, the pressure regulating valve 67 opens the inside of the pot 25 to the atmosphere. The steam generated inside the pot 25 is discharged towards the outside of the rice cooker 1 through the steam port 65. When the pressure regulating valve 67 is closed, the connection between the inside of the pot 25 and the outside of the rice cooker 1 is broken, and the inflow and outflow of gas through the steam discharge path 66 is restricted. At this time, the pressure regulating valve 67 seals the inside of the pot 25. The steam generated inside the pot 25 causes the internal pressure of the pot 25 to rise and exceed atmospheric pressure. By drawing out the gas from the pot 25 while the pressure regulating valve 67 is closed, the internal pressure of the pot 25 can also be reduced to below atmospheric pressure. By opening the pressure regulating valve 67 while the internal pressure of the pot 25 is reduced, the internal pressure of the pot 25 can also be restored to atmospheric pressure.

[0058] The pressure regulating valve 67 includes a valve body 67a that allows or disconnects the flow of gas in the steam discharge path 66, and a valve body drive unit 67c including a solenoid 67b that drives the valve body 67a to open and close. When steam inside the pot 25 is discharged towards the outside of the rice cooker 1, the solenoid 67b moves the valve body 67a in one direction to allow the flow of steam in the steam discharge path 66. Conversely, when the internal pressure of the pot 25 is increased or decreased, the solenoid 67b moves the valve body 67a in the other direction to disconnect the flow of steam in the steam discharge path 66. When the food being cooked in the pot 25 boils and generates steam, and this steam fills the pot 25, causing the internal pressure of the pot 25 to exceed a predetermined value, the valve body 67a is pushed up by the internal pressure of the pot 25, opening the steam discharge path 66. Furthermore, when the internal pressure of the pot 25 drops below the predetermined value, the valve body 67a closes the steam discharge path 66. Through the action of the valve body 67a, the internal pressure of the pot 25 is maintained above atmospheric pressure.

[0059] In addition, the lid 26 is equipped with a pressure reducing pump 68 that reduces pressure inside the pot 25 when the lid 26 is closed.

[0060] In addition, the cover 26 includes: an opening operation button 71 provided on the front half of the upper surface of the cover 26, a cover locking mechanism 72 for locking the opening and closing of the cover 26, an operation panel 73 as an input / output device, and an input / output control circuit board 75 for controlling the operation of the operation panel 73.

[0061] When the lid opening operation button 71 is operated, the lock between the lid 26 and the main body 23 of the pot receiving part 21 is released. When the lock between the lid 26 and the main body 23 is released, the spring force of the hinge spring 52 opens the lid 26 with the hinge shaft 51 as the center of rotation.

[0062] The lid locking mechanism 72 locks the lid 26 of the closing body 23. The lid locking mechanism 72 releases the lid 26 in conjunction with the operation of the lid opening operation button 71. Even if the lid opening operation button 71 is operated once, the lid locking mechanism 72 still restricts the opening of the lid 26 when the internal pressure of the pot 25 is increased or decreased. Only when the lid opening operation button 71 is operated again within a specified time will the lid locking mechanism 72 activate the pressure regulating valve 67 and the pressure reducing pump 68 to restore the internal pressure of the pot 25 to atmospheric pressure, after which the opening restriction of the lid 26 is released. The lid locking action of this lid locking mechanism 72 is controlled by the heating control circuit board 42. The detailed structure and control of the lid locking mechanism 72 can be, for example, the known technology described in Japanese Patent Application Publication No. 2015-171545. The lid locking action of the lid locking mechanism 72 is not always performed. When the lid locking action is not performed, the lid 26 can be opened by operating the lid opening operation button 71 once.

[0063] The control panel 73 is located on the upper surface of the cover 26 and the rice cooker 1, and is covered by the recess 55a of the outer cover 55. The control panel 73 includes a display 76 for displaying various information and an operation 77 for receiving various operations. In addition, the display 76 and the operation 77 are substantially mounted on the input / output control circuit board 75. The control panel 73 has a viewing window 73a through which the display of the display 76 can be seen, and a key top 73b corresponding to a decorative panel that allows the user to directly contact the operation 77.

[0064] The input / output control circuit board 75 is housed in the circuit board receiving recess 55b of the outer cover 55 and is positioned directly below the operation panel 73. The input / output control circuit board 75 includes: a microprocessor, a storage device for storing various arithmetic programs and parameters executed by the microprocessor, and a real-time clock (RTC) with a timing function. The storage device stores various settings (parameters) associated with multiple preset cycles. The real-time clock has the functions of recording the current time of the rice cooker 1 and timing. The real-time clock can be installed on either the heating control circuit board 42 or the input / output control circuit board 75.

[0065] Display unit 76 is an output device that displays the current status of rice cooker 1 in a visually confirmable manner. Display unit 76 may be, for example, a display and a light-emitting diode (LED). The display may be a liquid crystal display (LCD) or an organic EL panel (Organic Electro-Luminescence, Organic Light-Emitting Diode).

[0066] The operation unit 77 is an input device and a so-called touch sensor. The operation unit 77 is positioned directly above the display unit 76, covering it. The touch sensor includes multiple key elements arranged on a plane. Each key element includes, for example, a transparent electrode portion using a conductive polymer, a contact portion connected to the input / output control circuit board 75, and patterned wiring connecting the transparent electrode portion and the contact portion. By pressing, touching, or approaching any display element displayed on the display unit 76 with a fingertip, the key element positioned directly above that display element is operated. The operation received by the key element is output to the input / output control circuit board 75 as a selection of a display element on the display unit 76 displayed directly below it.

[0067] The user of rice cooker 1 can use the control unit 77 to select and input cooking conditions such as rice type, cooking method, hardness, and cooking time. Based on the program set by the operation of the control unit 77, rice cooker 1 performs standby cooking, heating of rice and water, keeping rice warm, and timed cooking standby, etc.

[0068] However, it can be assumed that the user of rice cooker 1 will operate the control panel 73 while facing the front of rice cooker 1. Therefore, the rice cooker 1 according to this embodiment includes: a lid opening operation button 71, which is disposed on the front half of the upper surface closer to the user facing the front of rice cooker 1; and a steam vent 65, which is disposed on the rear half of the upper surface farther from the user facing the front of rice cooker 1. As a result, the rice cooker 1 according to this embodiment can easily ensure a large space for arranging the display unit 76 between the lid opening operation button 71 and the steam vent 65, and can greatly adjust the size of the operation unit 77 disposed directly above the display unit 76. Therefore, rice cooker 1 can achieve: high visibility of the display unit 76, high operability of the operation unit 77, and high safety for the steam discharged from the steam vent 65.

[0069] Furthermore, the rice cooker 1 according to this embodiment does not have physical operation buttons, such as the cooking button and the off button, found in conventional rice cookers. It can be operated using only the operation unit 77. Therefore, the rice cooker 1 according to this embodiment saves the effort of searching for operation buttons, thus providing intuitive operation. In addition, the rice cooker 1 without physical operation buttons integrates the display unit 76 and the operation unit 77, thereby improving space utilization efficiency. Compared to conventional rice cookers where the input and output devices are scattered, it is easier to design an extremely beautiful appearance. Furthermore, the upper surface of the rice cooker 1 without physical operation buttons can be formed as a flat surface with almost no unevenness or a gently curved surface. These upper surface shapes of the rice cooker 1 make it easy to wipe and clean.

[0070] Figure 3 This is a cross-sectional view of the inner frame and heating coil of the rice cooker involved in this embodiment.

[0071] Figure 4 This is a bottom view of the inner frame and heating coil of the rice cooker according to this embodiment.

[0072] like Figure 3 as well as Figure 4 As shown, the heating coil 31 of the rice cooker 1 involved in this embodiment includes multiple coils 31u and 31d.

[0073] The first coil 31u is disposed on the outer side of the inner frame 37, and the second coil 31d is disposed on the bottom outer surface of the inner frame 37. The first coil 31u faces the lower part of the outer side of the pot 25 in a manner that clamps the inner frame 37. The second coil 31d faces the bottom outer surface of the pot 25 in a manner that clamps the inner frame 37.

[0074] This explains the movement of heat when the heating coil 31 is energized.

[0075] When the first coil 31u is energized, the lower outer surface of the pot 25 initially heats up. This heat is transferred to the main material 25a of the pot 25 and moves towards the water contained in the food being cooked, which is in contact with the lower inner surface of the pot 25. The movement of heat within the food is primarily water movement, occurring simultaneously with convection. Where rice is present in the food, water movement is confined to the narrow gaps between the rice grains, thus the movement of water and heat becomes sluggish. Conversely, where no rice is present, the movement of water and heat, i.e., convection, is active. Consequently, the water in the upper part of the food heats up following the water in contact with the lower inner surface. Because the rice grains settle towards the bottom of the pot 25 due to their own weight, the upper part of the food contains almost no rice grains and is essentially only water. Subsequently, in the central part of the food, the water and heat from the high-temperature upper part move towards the lower-temperature middle part of the food, and further towards the lower part of the food. This phenomenon is known as thermal convection, also referred to as "external convection" based on the first coil 31u.

[0076] Furthermore, when the second coil 31d is energized, the outer surface of the bottom of the pot 25 initially heats up. This heat is transferred to the main material 25a of the pot 25 and moves towards the water contained in the lower layer of the food being cooked, which is in contact with the inner surface of the bottom of the pot 25, also known as the pot bottom. Because the rice grains settle downwards due to their own weight, the pot bottom appears to be covered by the rice and water contained in the lower layer of the food being cooked. Therefore, the heat at the pot bottom causes the temperature and pressure of the water covering the pot bottom to rise. Subsequently, the water at the bottom, after its temperature and pressure increase, moves upwards through the gaps between the rice grains contained in the food being cooked. That is, the water heated in the lower layer of the food being cooked, i.e., hot water, moves towards the middle layer of the food being cooked along with the heat, and then towards the upper layer of the food being cooked. This phenomenon is called upward floating, also known as "internal convection" based on the second coil 31d.

[0077] Furthermore, when the first coil 31u and the second coil 31d are alternately energized, the food being cooked in the pot 25 will alternately generate external and internal convection. That is, when the first coil 31u and the second coil 31d are alternately energized, the alternating external and internal convection can promote the stirring of the water contained in the food being cooked in the pot 25, thereby reducing uneven heating of the food being cooked.

[0078] The heating control circuit board 42 of the rice cooker 1 according to this embodiment activates the heating coil 31 by performing various combinations of multiple energizing types, including the energizing time of the first coil 31u, the energizing time of the second coil 31d, the output of the first coil 31u, and the output of the second coil 31d. These multiple energizing types are stored in a storage unit.

[0079] One possible type of energization is as follows: after energizing the first coil 31u with a first output W1 and a first energization time T1, energizing the second coil 31d with a second output W2 and a second energization time T2. The respective energization times T1 and T2 are preferably several seconds or more. Thus, external and internal convection will alternately occur in the food being cooked within the pot 25 for a predetermined time or more. This alternation of external and internal convection promotes the stirring of the water in the food being cooked within the pot 25, thereby reducing uneven heating.

[0080] Preferably, the first energizing time T1 is different from the second energizing time T2. That is, preferably, the time for generating external convection is different from the time for generating internal convection under a certain energizing type.

[0081] The energizing type can also include a type where either the energizing time or the output of the heating coil 31 changes while the other remains constant. The energizing time of each coil 31 and 31d can be constant, while the output of each coil 31 and 31d can be different. Furthermore, the output of each coil 31 and 31d can be constant, while the energizing time of each coil 31 and 31d can be different.

[0082] Multiple energizing types can also include a type where the energizing of all heating coils 31 is disconnected during a no-energizing time. That is, the energizing type is: after energizing one of the two coils 31, 31d for a predetermined energizing time and output, after a first no-energizing time has elapsed, energizing the other of the two coils 31, 31d for a predetermined energizing time and output, and then waiting for a second no-energizing time to elapse. The first no-energizing time and the second no-energizing time can be the same or different.

[0083] Alternatively, the energizing type can also include: intermittently energizing only one of the two coils 31 and 31d while leaving the other coil 31 and 31d unenergized (no energization). This type of energizing involves energizing one of the two coils 31 and 31d for a specified energizing time and with a specified energizing output, while leaving both coils 31 and 31d unenergized for a specified energizing time. This type of energizing is suitable for heat preservation processes.

[0084] These types of energizing are performed repeatedly for a specified time or a specified number of times.

[0085] When switching the power-on type, the process switches from the first power-on type described below to the second power-on type described below. Specifically, the first power-on type involves energizing the first coil 31u with the first output W1 and a first power-on time T1, followed by energizing the second coil 31d with the second output W2 and a second power-on time T2. The second power-on type involves energizing the first coil 31u with the third output W3 and a third power-on time T3, followed by energizing the second coil 31d with the fourth output W4 and a fourth power-on time T4. Each power-on type is repeatedly executed for a specified time or a specified number of times before and after the switching.

[0086] The content of each power type, and the combination of multiple power types, can be set to suit the various processes included in the process.

[0087] In the energized type, the output adjustment of the first coil 31u and the output adjustment of the second coil 31d are based on, for example, PWM control (Pulse Width Modulation).

[0088] Next, the cover 26 will be described in detail.

[0089] Figure 5 This is an exploded perspective view of the rice cooker according to this embodiment, and it shows the state of the operation panel with the lid removed.

[0090] Figure 6 This is a plan view of the outer lid of the rice cooker according to this embodiment.

[0091] Figure 7 This is an enlarged cross-sectional view of the outer cover of the rice cooker according to this embodiment, and a cross-sectional view of the surface that runs through the circuit board receiving recess in the width direction of the rice cooker.

[0092] like Figure 5 as well as Figure 6 As shown, the lid 26 of the rice cooker 1 according to this embodiment includes: an outer cover 55 having a recessed portion 55a that opens away from the main body 23 and is covered by an outer cover cover 56; and an operation panel 73, which serves as the upper surface panel and is covered by the recessed portion 55a. A small gap is formed between the operation panel 73 and the component adjacent to the operation panel 73, i.e., the outer cover 55. This gap is not wide enough to allow for a rapid flow of liquid, such as the ample water present in a kitchen where the rice cooker 1 is placed. However, it is still sufficient for liquid to penetrate into the interior of the lid 26 through the gap between the operation panel 73 and the outer cover 55 by means of capillary action.

[0093] Therefore, in addition to Figure 5 as well as Figure 6In addition, for example Figure 7 As shown, the outer cover 55 of the cover 26 according to this embodiment has a drainage groove 82 provided along at least a portion of the edge of the recess 55a. When liquid seeps into the recess 55a through the gap between the operation panel 73 and the outer cover 55, the drainage groove 82 guides the liquid to an outlet hole 81, which then allows the liquid to flow toward the space defined by the outer cover 55 and the outer cover cover 56. The drainage groove 82 replenishes the liquid that seeps into the interior of the cover 26 through the gap between the operation panel 73 and the outer cover 55 before it flows toward the center of the recess 55a, allowing the liquid to flow out through the outlet hole 81 toward the space defined by the outer cover 55 and the outer cover cover 56.

[0094] However, in recent years, from the perspective of volume setting, the demand for miniaturization of the rice cooker 1 has increased. On the other hand, from the perspective of visibility of the display unit 76, the demand for larger text display is increasing, and from the perspective of operability of the operation unit 77, the demand for larger key tops 73b is also increasing. That is, there is a demand for miniaturization of the cover 26, and on the other hand, there is a demand for larger input / output control circuit board 75. As a result, the proportion of the circuit board receiving recess 55b to the recess 55a of the outer cover 55 is increased, so that the edge of the recess 55a and the edge of the circuit board receiving recess 55b are close in appearance.

[0095] Furthermore, if liquid seeps into the recess 55a through the gap between the operation panel 73 and the outer cover 55, the liquid may flow into the circuit board receiving recess 55b near the edge of the recess 55a. The circuit board receiving recess 55b houses the input / output control circuit board 75, which is equipped with the operation unit 77 as an input device and the display unit 76 as a display device. Therefore, when liquid flows into the circuit board receiving recess 55b, it can cause a malfunction of the input / output control circuit board 75 housed therein.

[0096] Therefore, the drain channel 82 is laid at least along the portion of the circuit board receiving recess 55b and the depression 55a that are close together. For convenience, the portion of the drain channel 82 laid along the portion of the circuit board receiving recess 55b and the depression 55a is referred to as the "narrow drain channel 82a", and the drain channels 82 other than the narrow drain channel 82a are also referred to as the "non-narrow drain channel 82b" for convenience. The narrow drain channel 82a extends along the left and right sides of the circuit board receiving recess 55b in the front-back direction of the rice cooker 1.

[0097] The holes 81 are preferably multiple. Multiple holes 81 can facilitate the discharge of liquid replenished by the drain 82 over a wide area of ​​the drain 82.

[0098] The plurality of holes 81 include: a plurality of side drainage holes 81a disposed within a narrow drainage groove 82a in a drainage groove 82, and a plurality of front drainage holes 81b disposed at the leading edge of a recess 55a. In other words, the plurality of holes 81 include: at least a plurality of side drainage holes 81a disposed at the portion of the circuit board receiving recess 55b that is close to the recess 55a.

[0099] Multiple side drain holes 81a allow the liquid replenished by the narrow drain 82a and the liquid replenished by the non-narrow drain 82b and flowing into the narrow drain 82a to flow rapidly toward the upper surface of the outer cover 56, thereby reliably preventing liquid from overflowing toward the circuit board receiving recess 55b.

[0100] A front drain hole 81b is located next to the lid locking mechanism 72. Liquid discharged from the front drain hole 81b passes through the gap between the opening 73c of the operation panel 73 exposed by the lid opening operation button 71 and the lid opening operation button 71, and enters the lid body 26. It then passes next to the lid locking mechanism 72 and merges with the liquid received by the outer cover 56. The structure for discharging the merged liquid out of the pot can be based on known technology, such as that described in Japanese Patent Application Laid-Open No. 2023-151879.

[0101] The left and right edges of the circuit board receiving recess 55b are close to the left and right edges of the recess 55a. On the other hand, the front edge of the circuit board receiving recess 55b is separated from the front edge of the recess 55a, and the rear edge of the circuit board receiving recess 55b is separated from the rear edge of the recess 55a. A narrow portion drainage groove 82a is disposed between the left and right edges of the circuit board receiving recess 55b and the left and right edges of the recess 55a. A non-narrow portion drainage groove 82b is laid along the front edge and the rear edge of the recess 55a.

[0102] The drainage channel 82 can also be laid along the entire circumference of the edge of the depression 55a. Multiple holes 81 can also be discretely arranged along the entire length of the drainage channel 82, including the narrow drainage channel 82a.

[0103] With the lid 26 closed and the main body 23 closed, the drain trough 82 tilts downwards from the back side to the front side of the rice cooker 1. Liquid flowing into the narrow drain trough 82a passes through the side drain hole 81a and flows rapidly outwards towards the upper surface of the outer cover 56, which serves as a drain tray. Liquid flowing into areas other than the narrow drain trough 82a is replenished in the drain trough 82, expanding along the drain trough 82 in proportion to the liquid volume. Liquid trapped in the drain trough 82 that is further back than the narrow drain trough 82a reaches the side drain hole 81a and flows outwards towards the upper surface of the outer cover 56. Liquid trapped in the drain trough 82 that is further forward than the narrow drain trough 82a reaches the front drain hole 81b and flows outwards towards the upper surface of the outer cover 56. The structure for discharging liquid flowing out of the upper surface of the outer cover 56 to the outside of the pot can be made using known technologies, such as those described in Japanese Patent Application Publication No. 2023-141040.

[0104] Figure 8 This is an enlarged cross-sectional view of the outer lid of the rice cooker according to this embodiment, and it is a cross-sectional view along the drain groove.

[0105] Apart from Figure 5 as well as Figure 6 In addition, for example Figure 8 As shown, the depth of the narrow drainage groove 82a of the cover 26 according to this embodiment is deeper than the depth of the non-narrow drainage groove 82b. The narrow drainage groove 82a, which is like a deep pit, can prevent liquid replenished by the narrow drainage groove 82a and liquid replenished by the non-narrow drainage groove 82b and flowing into the narrow drainage groove 82a from overflowing into the circuit board receiving recess 55b.

[0106] Furthermore, the front and rear edges of the circuit board receiving recess 55b are isolated from the front and rear edges of the recess 55a compared to the left and right edges of the circuit board receiving recess 55b and the recess 55a. Therefore, even if liquid overflows from the non-narrow portion drain groove 82b, liquid will not immediately flow into the circuit board receiving recess 55b. Additionally, it is difficult to imagine that liquid overflowing from the non-narrow portion drain groove 82b would reach the circuit board receiving recess 55b and cause a large amount of liquid to flow into the interior of the cover 26 through the gap between the operation panel 73 and the outer cover 55.

[0107] The outer cover 55 includes a rib 83 positioned above the side drainage hole 81a and mounted on the drainage groove 82. Since the left and right edges of the circuit board receiving recess 55b are close to the left and right edges of the recess 55a, when the outer cover 55 is molded from synthetic resin, the presence of the side drainage hole 81a on the outer cover 55 poses a molding risk where the outer surface of the outer cover 55, corresponding to the dam defining the recess 55a, is poured into the inner side of the recess 55a. Therefore, by mounting the rib 83 above the side drainage hole 81a, the outer cover 55 can be molded as desired.

[0108] The rice cooker 1 of this embodiment, configured as described above, includes a drain groove 82 provided along at least a portion of the edge of the recess 55a. When liquid seeps into the recess 55a through the gap between the control panel 73 and the outer cover 55, the drain groove 82 guides the liquid toward a hole 81, which allows the liquid to flow out toward the space defined by the outer cover 55 and the outer cover 56. Thus, the drain groove 82 replenishes the liquid that seeps into the interior of the lid 26 through the gap between the control panel 73 and the outer cover 55 before it flows toward the center of the recess 55a, allowing the liquid to flow out through the hole 81 toward the space defined by the outer cover 55 and the outer cover 56.

[0109] Furthermore, the rice cooker 1 according to this embodiment includes a plurality of holes 81 provided in the drain tank 82. This allows the rice cooker 1 to facilitate the drainage of liquid replenished in the drain tank 82 over a wide area.

[0110] Furthermore, the rice cooker 1 according to this embodiment includes a rib 83 disposed above the hole 81 and mounted on the drain groove 82. Therefore, even if the side drain hole 81a is provided on the outer cover 55, which is a molded product of synthetic resin, it is possible to prevent the outer surface of the outer cover 55, which corresponds to the dam defining the recess 55a, from falling into the inside of the recess 55a. Thus, the rice cooker 1 can have an outer cover 55 with a desired outer surface.

[0111] Furthermore, the rice cooker 1 according to this embodiment includes a drainage channel 82, or narrow drainage channel 82a, laid at least along the portion of the circuit board receiving recess 55b and depression 55a. Thus, the rice cooker 1 can simultaneously meet the needs of miniaturization, improved visibility of the display 76, and improved operability of the operation unit 77, thereby reliably preventing malfunctions of the supposedly large input / output control circuit board 75 due to liquids such as water.

[0112] Furthermore, the rice cooker 1 according to this embodiment includes at least one hole 81, i.e., a side drain hole 81a, located near the recessed portion 55b and the concave portion 55a of the circuit board receiving recess. This allows the rice cooker 1 to rapidly drain the liquid replenished by the narrow drain groove 82a towards the space defined by the outer cover 55 and the outer cover 56, thereby reliably preventing malfunctions in the input / output control circuit board 75.

[0113] Therefore, the rice cooker 1 of the present invention can smoothly drain the liquid that has entered the interior of the lid 26 from the gap between the operation panel 73, which corresponds to the top plate of the lid 26, and the outer cover 55, which is its adjacent component.

[0114] While several embodiments of the present invention have been described, these embodiments are provided as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, modifications, etc., can be made without departing from the spirit of the invention. These embodiments, or their variations, are included within the scope or spirit of the invention, and are included within the scope of the invention as described in the claims and its equivalents.

Claims

1. An electric rice cooker comprising: a pot capable of holding food to be cooked; a main body having a pot receiving portion capable of receiving the pot; and a lid capable of opening and closing the pot receiving portion, characterized in that, The cover comprises: an outer cover that covers the main body when the cover is closed; an outer cover having a recess that opens away from the main body and is covered by the outer cover; and an upper surface panel that covers the recess. The outer cover has a drainage groove disposed along at least a portion of the edge of the recess, which guides liquid into the recess by means of liquid entering the recess through the gap between the upper surface panel and the outer cover, wherein the drainage groove is used to direct the liquid out through the hole, wherein the hole is used to direct the liquid out toward the space defined by the outer cover and the outer cover cover.

2. The rice cooker according to claim 1, characterized in that, Multiple holes are provided in the drainage channel.

3. The rice cooker according to claim 1 or 2, characterized in that, The rice cooker has a rib positioned above the hole and supported on the drain trough.

4. The rice cooker according to claim 1 or 2, characterized in that, The outer cover has a circuit board receiving recess disposed within the recess and for accommodating an input / output control circuit board on which an input device and a display device are mounted. The upper surface panel includes: an operation section for the input device, and a viewing window through which the display of the display device is visible. The drainage channel is laid at least along the portion of the circuit board receiving recess that is close to the depression.

5. The rice cooker according to claim 4, characterized in that, The hole is disposed at least at a location close to the recess and the depression in the circuit board receiving portion.

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