Electric heating cooking utensil

Abstract

The utility model discloses an electric heating cooking utensil which comprises an outer pot, an inner container arranged in the outer pot and a heating disc arranged between the outer pot and the bottom of the inner container, the outer pot further comprises a temperature control element, the temperature control element is in contact with the bottom face of the inner container to sense temperature, and the bottom face of the inner container comprises an attaching arc face attached to the heating disc and an attaching plane attached to the temperature control element. A protruding part is arranged between the attaching cambered surface and the attaching plane, and a heat insulation gap is formed between the protruding part and the heating disc. Due to the arrangement of the heat insulation gap, the distance between the heat insulation gap and the heating disc is increased, part of heat in the area around the central opening of the heating disc can be lost in the heat insulation gap, and the heat radiation speed to the center of the bottom wall of the inner container (the temperature control element) is also slowed down due to the existence of the heat insulation gap. Therefore, heat concentration at the center of the bottom wall of the inner container is avoided, the temperature of the area is closer to the actual temperature of the inner container, and the detection accuracy of the temperature control element is improved.

Description

Technical Field

[0001] This utility model belongs to the field of kitchen appliance technology, specifically relating to an electric heating cooking appliance. Background Technology

[0002] Electric heating cooking appliances (such as rice cookers and electric pressure cookers) generally include an outer pot and an inner pot. The inner pot is used to hold food. A heating plate is installed between the bottom of the inner pot and the outer pot. When the power is turned on, the heating plate generates heat, which then heats and cooks the food inside the inner pot by contacting the bottom of the inner pot.

[0003] A temperature control element is typically located at the bottom of the inner liner. This element passes through the heating plate and contacts the bottom wall of the inner liner to detect its temperature. To ensure good contact between the bottom wall of the inner liner and the heating plate, and to guarantee proper heating of the inner liner, current technology usually designs the bottom wall of the inner liner as a concave structure, making the entire bottom wall of the inner liner a curved surface, thus allowing for better contact with the heat-conducting surface of the heating plate. However, the contact surface between the temperature control element and the inner liner is often a flat structure. This results in the temperature control element not being able to completely fit with the inner liner, often leaving a gap between them. This means the temperature control element is in a state of "temperature measurement without contact," leading to inaccurate temperature detection.

[0004] In response to this, Chinese patent CN115530600A discloses an IH rice cooker with uniform heating. The bottom wall of the inner pot has an upward-curving center forming a concave portion, and a first flat portion is located at the center of this concave portion. A temperature sensor contacts this first flat portion at the center of the concave portion, thus ensuring the accuracy of the temperature sensor to a certain extent.

[0005] In addition, Chinese patent CN203555621U discloses an inner pot and a rice cooker having the inner pot. The outer surface of the bottom of the pot is a concave arc surface, and the outer surface of the bottom of the pot is provided with a planar temperature sensing area that contacts the thermostat, so as to abut against the thermostat and make the thermostat fully contact the inner pot.

[0006] Both of the above solutions incorporate a planar structure within the concave arc surface of the inner liner's bottom wall to facilitate contact with the temperature control element, ensuring sufficient contact between the element and the liner. However, in practice, especially in models using a heating plate, the perimeter of the opening at the center of the heating plate through which the temperature control element passes contacts the bottom surface of the inner liner. This contact transfers heat not only to the upper inner liner but also to the center of the inner liner's bottom wall via thermal radiation. The transition area between the concave arc surface and the planar structure on the bottom wall of the inner liner forms a heat accumulation zone, causing radiated heat to concentrate and become difficult to dissipate. Consequently, the temperature in the central area of ​​the inner liner's bottom wall, where the temperature control element is located, is higher than the actual temperature of the inner liner, resulting in inaccurate temperature readings that do not accurately reflect the temperature of the inner liner.

[0007] Furthermore, Chinese patent CN204427780U discloses a heating plate assembly for an electric hot pot and an electric hot pot having the same assembly. This assembly features a protrusion on the heat-conducting plate, away from the recessed bottom wall of the inner pot. A cavity is defined between the protrusion and the inner pot, and the temperature sensing section of the temperature sensing component extends into the cavity and contacts the bottom wall of the inner pot. The air within the cavity acts as insulation, reducing the heat radiated from the heat-conducting plate to the center of the bottom wall of the inner pot, i.e., the temperature sensing end.

[0008] However, firstly, heat-conducting plates are typically formed through casting, and after molding, they require deburring, making the process difficult and complex. Therefore, adding a localized recessed structure to the heat-conducting plate not only further increases the processing difficulty and generates more waste, increasing product costs, but also affects its contact with the inner pot, impacting heating efficiency. Furthermore, it leads to a thinner heat-conducting plate, increasing the risk of melting during dry burning.

[0009] Furthermore, because the bottom wall of the inner liner is an inwardly concave arc surface, the structural strength of the bottom wall of the inner liner is relatively low. In order to improve the strength and avoid damage and deformation, it is often necessary to process a bottom sheet through a bottom-covering process, which results in a higher manufacturing cost for the inner liner. Utility Model Content

[0010] This utility model provides an electric heating cooking appliance to solve the problems that the heat from the heating plate tends to accumulate at the center of the bottom wall of the inner pot, which is the temperature control element, resulting in inaccurate temperature detection by the temperature control element, as well as the high cost of modifying the heating plate and the increased processing difficulty.

[0011] The technical solution adopted in this utility model is as follows:

[0012] An electric cooking appliance includes an outer pot, an inner pot placed inside the outer pot, and a heating plate disposed between the bottom of the outer pot and the inner pot. The outer pot also includes a temperature control element that contacts and senses temperature with the bottom surface of the inner pot. The bottom surface of the inner pot includes a fitting arc surface that fits against the heating plate and a fitting plane that fits against the temperature control element. A raised portion is provided between the fitting arc surface and the fitting plane, and a heat insulation gap is formed between the raised portion and the heating plate.

[0013] In this invention, the bottom wall of the inner liner is provided with a conforming arc surface and a conforming plane. The conforming arc surface is adapted to the shape of the arc-shaped heat transfer surface on the upper surface of the heating plate, thereby ensuring a good fit with the heating plate, increasing the contact area between the two, and allowing the heat from the heating plate to be transferred to the conforming arc surface more efficiently, reducing heat loss and improving heating efficiency. The conforming plane is adapted to the contact plane on the top of the temperature control element. Both are planar structures, which also ensure a good fit, allowing the temperature control element to make full contact with the conforming plane and more accurately detect the temperature of the inner liner.

[0014] In addition, a raised portion is provided between the mating plane and the mating arc surface. The raised portion bulges towards the inside of the inner liner, thereby forming a heat insulation gap between the outer bottom wall of the inner liner and the heating plate. The setting of the heat insulation gap increases the distance between this area and the heating plate, allowing some of the heat in the area around the central opening of the heating plate to be lost within the heat insulation gap. Furthermore, the existence of the heat insulation gap also slows down the rate at which heat radiates to the center of the bottom wall of the inner liner (at the temperature control element). This not only reduces the amount of heat radiated to the temperature control element but also slows down the rate at which heat radiates to the temperature control element, thus preventing heat concentration at the center of the bottom wall of the inner liner. This makes this area closer to the actual temperature of the inner liner and improves the detection accuracy of the temperature control element.

[0015] Furthermore, the raised section, located between the mating plane and the mating arc surface, enhances the overall strength of the inner liner's bottom wall, particularly at the transition point between the mating plane and the arc surface, reducing the risk of deformation and damage. Simultaneously, it eliminates the need for a bottom sheet, simplifying the inner liner manufacturing process, saving costs, and improving production efficiency.

[0016] Furthermore, this invention eliminates the need for modifications to the structure and surface of the heating plate, allowing the use of a standard heating plate as the heat source. The processing and manufacturing of the inner liner is simpler and easier than that of the heating plate itself, thus reducing the overall processing steps and complexity, and saving costs and materials. Simultaneously, the thickness of the heating plate is guaranteed, resulting in a longer service life.

[0017] The fitting plane is located in the central area of ​​the bottom surface of the inner liner, the fitting arc surface surrounds the outer periphery of the fitting plane, and the outer periphery of the fitting plane is surrounded by raised ribs, which form a raised part.

[0018] In this design, the contact plane, raised portion, and contact arc surface are concentric circles, arranged sequentially from the center of the inner liner's bottom wall outwards. This not only facilitates processing but also ensures the contact area between the contact arc surface and the heating plate, guaranteeing both accurate temperature detection and heating efficiency. The raised ribs protrude inwards towards the inner liner, forming a heat-insulating gap below them. This increases the gap between the ribs and the heating plate, as well as the surface area of ​​the inner liner's bottom wall, thus increasing the heat transfer area between the food and the inner liner's bottom wall and improving the food's heating effect.

[0019] There is a first transition arc surface between the rib and the mating plane, and a second transition arc surface between the rib and the mating arc surface. The curvature of the first transition arc surface is greater than the curvature of the second transition arc surface.

[0020] In this design, both the inner and outer sides of the raised rib feature curved transitions, resulting in a smoother connection between the rib and the contact surface and the curved surface. This avoids sharp corners, preventing food accumulation and cleaning difficulties. Furthermore, because the curved surface gradually extends radially outwards and downwards along the inner liner, its height decreases, placing it below the contact surface. By reducing the curvature of the second transition curved surface, the transition between the raised rib and the curved surface is smoother, facilitating heat transfer on the bottom wall of the inner liner and food placement. The larger curvature of the first transition curved surface acts as a barrier against food and heat within the contact surface, reducing food sliding from the contact surface to the curved surface (the edge of the inner liner). This ensures food is evenly distributed on the bottom wall of the inner liner, preventing excessive food accumulation in certain areas and affecting heating. Simultaneously, it concentrates heat within the contact surface, better heating food in that area and ensuring uniform heating across all regions.

[0021] The heating plate has an opening in the center for the temperature control element to extend out, and the projection of the raised part toward the heating plate is at least partially located inside the opening.

[0022] In this design, at least a portion of the raised section corresponds vertically to the opening, allowing the insulation gap to connect with the opening. As a result, the heat accumulated in the insulation gap can dissipate through the opening, enabling timely heat dissipation in the central area of ​​the inner liner bottom wall. This prevents a large amount of heat from accumulating in the mating plane and insulation gap, which could affect the detection accuracy of the temperature control element.

[0023] The heating plate has a heating element embedded inside, and the projection of the heating element toward the inner liner is located on the fitting arc surface.

[0024] In this design, the heating element serves as the heat source for the heating plate and is positioned vertically opposite to the contact surface. This ensures that the heat generated by the heating element is transferred to the contact surface via the heat transfer arc of the heating plate, guaranteeing full contact between the heating plate area near the heating element and the inner liner, thus ensuring effective heating. Simultaneously, the raised portion, located inside the heating element and offset vertically from it, reduces heat radiated to the raised portion, preventing excessive temperature rise at the raised portion and the contact surface.

[0025] The raised portion includes a top wall and transition sections located on both sides of the top wall. The heat insulation gap includes a first gap between the top wall and the heating plate, and a second gap between the transition section and the heating plate. The first gap is no greater than 5mm.

[0026] In this design, if the first gap is too large, it will affect the fit between the bottom wall of the inner pot and the heating plate, resulting in a decrease in the heat transfer efficiency from the heating plate to the inner pot. The first gap is no more than 5mm, which can ensure the heat insulation effect of the heat insulation gap and reduce the radiation of heat to the mating plane, while ensuring the contact effect between the heating plate and the bottom wall of the inner pot, and ensuring the heating effect of food.

[0027] The protrusion height of the raised portion relative to the mating surface is H, where H≤5mm.

[0028] In this design, the protruding ridges not only effectively improve the structural strength of the inner liner bottom wall, but also, with a protrusion height of no more than 5mm, prevent the inner liner bottom wall from experiencing significant unevenness, thus facilitating subsequent polishing and reducing processing difficulty.

[0029] The inner liner has a single-layer plate structure, and the wall thickness of the inner liner is no more than 0.7mm.

[0030] In this design, the inner liner is a single-layer board structure with no decorative coating on the outer surface. This simplifies the processing steps, improves production efficiency, and saves costs while ensuring non-stick properties and an aesthetically pleasing appearance. Furthermore, the raised sections increase the structural strength of the inner liner, allowing even a thin, single-layer liner to possess high structural strength and resist deformation.

[0031] The diameter of the contact plane is D1, and the top of the temperature control element has a contact plane with a diameter of D2, where D1 > D2.

[0032] In this design, the diameter of the contact surface is larger than the diameter of the contact surface at the top of the temperature control element. This not only ensures full contact between the temperature control element and the contact surface for more accurate temperature measurement, but also allows for a certain margin to compensate for misalignment of the inner liner. Even if the inner liner is slightly offset relative to the heating plate, i.e., the center line of the inner liner is slightly misaligned with the center line of the heating plate, it can still ensure that the contact surface can make contact with the contact surface, thereby accurately measuring the temperature of the inner liner.

[0033] The bottom of the side wall of the inner liner is provided with heat-retaining ridges, which are spaced apart along the circumference of the inner liner and extend upward in a spiral shape.

[0034] In this design, the heat-retaining ridges create an uneven surface on the bottom of the inner pot's sidewall, which facilitates heat accumulation. Furthermore, these ridges increase the surface area of ​​the inner pot's sidewalls, thereby increasing the heat transfer area and allowing more heat to be transferred to the sidewalls and ultimately to the food inside. This improves the heating effect on the food at the bottom of the inner pot's sidewalls, resulting in more even heating throughout the inner pot and enhanced cooking performance. Simultaneously, the spiral shape of the ridges helps heat flow upwards from the perimeter of the inner pot, extending the heat flow path and increasing the contact time between the heat and the food inside, further improving the heating effect. Attached Figure Description

[0035] The accompanying drawings, which are included to provide a further understanding of the present invention and constitute a part of this invention, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings:

[0036] Figure 1 This is a cross-sectional view of an electric heating cooking appliance according to one embodiment of the present invention;

[0037] Figure 2 This is a cross-sectional view of the inner liner according to one embodiment of the present invention;

[0038] Figure 3 This is a cross-sectional view of a portion of the structure of an electric heating cooking appliance according to one embodiment of the present invention;

[0039] Figure 4 for Figure 3 A magnified view of area A in the middle;

[0040] Figure 5 This is a schematic diagram of the inner liner according to one embodiment of the present invention;

[0041] Figure 6 for Figure 5 Top view of the inner liner;

[0042] Figure 7 This is a schematic diagram of the inner liner in another embodiment of the present invention.

[0043] in:

[0044] 1. Outer pot;

[0045] 2 Inner liner; 21 Fitting plane; 22 Fitting arc surface; 23 Raised part; 231 Rib; 232 Top wall; 233 First transition arc surface; 234 Second transition arc surface; 235 Transition section; 24 Insulation gap; 25 Heat-concentrating ridge;

[0046] 3. Heating plate; 31. Heating element; 32. Opening; 33. Mounting protrusion;

[0047] 4. Temperature control components. Detailed Implementation

[0048] To more clearly illustrate the overall concept of this utility model, a detailed description will be provided below with reference to the accompanying drawings.

[0049] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0050] Furthermore, it should be understood in the description of this utility model that the terms "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0051] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0052] In this invention, unless otherwise expressly specified and limited, the first feature "on" or "below" the second feature may be in direct contact with the first and second features, or indirect contact through an intermediate medium. In the description of this specification, references to terms such as "implementation," "example," "aspect," or "specific example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0053] like Figures 1 to 4 As shown, an electric cooking appliance includes an outer pot 1, an inner pot 2 placed inside the outer pot 1, and a heating plate 3 disposed between the bottom of the outer pot 1 and the inner pot 2. The outer pot 1 also includes a temperature control element 4, which contacts the bottom surface of the inner pot 2 to sense temperature. The bottom surface of the inner pot 2 includes a fitting arc surface 22 that fits against the heating plate 3 and a fitting plane 21 that fits against the temperature control element 4. A raised portion 23 is provided between the fitting arc surface 22 and the fitting plane 21, and a heat insulation gap 24 is formed between the raised portion 23 and the heating plate 3.

[0054] Specifically, such as Figure 1 As shown, the upper surface of the heating plate 3 has a heat transfer arc surface.

[0055] Preferably, the temperature control element 4 includes a detection cover and an elastic element, such as a spring, located below the detection cover, so that the detection cover can float up and down under the pressure of the inner liner 2, thereby maintaining the contact effect between the detection cover and the contact surface 21.

[0056] In this invention, the bottom wall of the inner liner 2 is provided with a conforming arc surface 22 and a conforming plane 21. The conforming arc surface 22 is adapted to the shape of the arc-shaped heat transfer surface on the upper surface of the heating plate 3, thereby ensuring a good fit with the heating plate 3, increasing the contact area between the two, and allowing the heat from the heating plate 3 to be transferred to the conforming arc surface 22 with higher efficiency, reducing heat loss and improving heating efficiency. The conforming plane 21 is adapted to the contact plane on the top of the temperature control element 4. Both are planar structures, which also ensure a good fit, allowing the temperature control element 4 to fully contact the conforming plane 21 and more accurately detect the temperature of the inner liner 2.

[0057] In addition, a raised portion 23 is provided between the mating plane 21 and the mating arc surface 22. The raised portion 23 protrudes towards the inside of the inner liner 2, thereby forming a heat insulation gap 24 between the outer bottom wall of the inner liner 2 and the heating plate 3. The setting of the heat insulation gap 24 increases the distance between this area and the heating plate 3, allowing some of the heat in the area around the central opening 32 of the heating plate 3 to be lost within the heat insulation gap 24. Furthermore, the presence of the heat insulation gap 24 also slows down the rate at which heat radiates to the center of the bottom wall of the inner liner 2 (at the temperature control element 4). This not only reduces the amount of heat radiated to the temperature control element 4, but also slows down the rate at which heat radiates to the temperature control element 4, thereby preventing heat concentration at the center of the bottom wall of the inner liner 2 and making this area closer to the actual temperature of the inner liner 2, thus improving the detection accuracy of the temperature control element 4.

[0058] Furthermore, the presence of the raised portion 23, located between the mating plane 21 and the mating arc surface 22, enhances the overall strength of the bottom wall of the inner liner 2, particularly the strength at the transition point between the mating plane 21 and the mating arc surface 22, thus reducing the risk of deformation and damage to the bottom wall of the inner liner 2. Simultaneously, it eliminates the need for a bottom sheet, simplifying the manufacturing process of the inner liner 2, saving costs, and improving production efficiency.

[0059] Furthermore, in this invention, there is no need to modify the structure or surface of the heating plate 3; a universal heating plate 3 can be used as the heat source. The processing and manufacturing of the inner liner 2 is simpler and easier to operate compared to the heating plate 3, thereby reducing the processing steps and difficulty of the entire machine, saving costs and materials. At the same time, the thickness of the heating plate 3 is also guaranteed, resulting in a longer service life.

[0060] Preferably, the inner liner 2 has a single-layer plate structure and the wall thickness of the inner liner 2 is no more than 0.7 mm.

[0061] In the prior art, in order to process the arc-shaped structure of the bottom wall of the inner liner so that it fits better with the heating plate and to avoid deformation of the inner liner during processing, the wall thickness of the inner liner is often designed to be greater than 0.7mm. In particular, the bottom wall may even be made into a multi-layer structure or have an additional fixed bottom cover. This is because when the wall thickness is thin, the structural strength of the inner liner is weak. When processing the arc-shaped structure at the bottom, the inner liner will often deform, resulting in a large deviation in the curvature, which will prevent it from fitting well with the heating plate.

[0062] The raised portion 23 in this application increases the structural strength of the inner liner 2, making the single-layer inner liner 2 also possess high structural strength and less prone to deformation. It also allows the inner liner 2 to be designed as a single-layer plate structure with a wall thickness of 0.7mm or less, making the inner liner 2 thinner and lighter while maintaining a good structural shape during processing.

[0063] Preferably, the wall thickness of the inner liner is 0.5 mm.

[0064] Of course, as another embodiment, the wall thickness of the bottom of the inner liner can be different from the wall thickness of the side wall of the inner liner. For example, by setting the bottom bulge of the bottom sheet, the wall thickness of the bottom of the inner liner can be set to 0.7mm or less, and the side wall can be thinner, so as to achieve cost reduction while meeting the strength requirements.

[0065] The inner liner 2 is preferably made of stainless steel, but it can also be made of other metals or alloys such as titanium, and there is no limitation on this.

[0066] It should be noted that the present invention does not limit the structure of the raised part 23. It can be a groove structure provided on the outer side of the bottom wall of the inner liner 2, that is, the outer side of the bottom wall of the inner liner 2 is recessed upward to form the raised part 23, so that the thickness of the bottom wall of the inner liner 2 in this area is reduced, thereby forming a heat insulation gap 24 between it and the heating plate 3, while there is no obvious height change on the inner side of the bottom wall of the inner liner 2.

[0067] As a preferred implementation method, such as Figure 2 , Figure 5 , Figure 6 As shown, the fitting plane 21 is located in the central area of ​​the bottom surface of the inner liner 2, the fitting arc surface 22 surrounds the outer periphery of the fitting plane 21, and the outer periphery of the fitting plane 21 is surrounded by a rib 231, which forms a raised portion 23.

[0068] In this embodiment, the rib 231 protrudes into the inner liner 2 to form a raised portion 23, thereby creating a heat insulation gap 24 on the outer side of the bottom wall of the inner liner 2 and a protruding structure on the inner side. In this embodiment, the thickness of the bottom wall of the inner liner 2 does not change significantly, making the wall thickness of the bottom wall of the inner liner 2 more uniform and consistent, which can ensure the structural strength of the bottom of the inner liner 2.

[0069] The contact surface 21, the raised portion 23, and the contact arc surface 22 are concentric circles, arranged sequentially from the center of the bottom wall of the inner liner 2 outwards. This not only facilitates processing but also ensures the contact area between the contact arc surface 22 and the heating plate 3, thereby ensuring accurate temperature detection and heating efficiency. The rib 231 protrudes towards the inside of the inner liner 2, forming a heat insulation gap 24 on its lower side. This increases the gap between the rib and the heating plate 3, as well as the surface area of ​​the inner bottom wall of the inner liner 2, thus increasing the heat transfer area between the food and the bottom wall of the inner liner 2 and improving the heating effect of the food.

[0070] Preferably, such as Figure 5 , Figure 6 As shown, the rib 231 can be a complete annular structure that completely surrounds the outer periphery of the mating plane 21. The rib 231 can also be multiple discontinuous arc segments arranged at intervals along the circumference of the mating plane 21, which is not limited here.

[0071] In a preferred embodiment, such as Figure 3 , Figure 4 As shown, there is a first transition arc surface 233 between the rib 231 and the mating plane 21, and a second transition arc surface 234 between the rib 231 and the mating arc surface 22. The curvature of the first transition arc surface 233 is greater than the curvature of the second transition arc surface 234.

[0072] The inner and outer sides of the rib 231 are both curved, making the connection between the rib 231 and the contact surface 21 and the contact curved surface 22 more rounded, avoiding corners and thus preventing food from accumulating in corners and making cleaning inconvenient. Furthermore, since the contact curved surface 22 gradually extends radially outward and downward along the inner liner 2, its height gradually decreases. Therefore, the position of the contact curved surface 22 is lower than that of the contact surface 21, and the distance between it and the top surface of the rib 231 is greater. By reducing the curvature of the second transition curved surface 234, the transition between the rib 231 and the contact curved surface 22 is smoother, facilitating heat transfer on the bottom wall of the inner liner 2 and food placement. The first transition curved surface 233 has a larger curvature, which can provide some barrier to food and heat within the contact surface 21, reducing the sliding of food from the contact surface 21 to the contact curved surface 22, i.e., the edge of the inner liner 2. This allows food to be evenly distributed on the bottom wall of the inner liner 2, thus preventing excessive local accumulation of food within the inner liner 2 and affecting heating. At the same time, it can also concentrate the heat within the contact plane 21, better heat the food in that area, and ensure the uniform heating of food in each area.

[0073] Of course, the curvature of the first transition arc surface 233 and the second transition arc surface 234 can also be the same to reduce the processing difficulty, which is not limited here.

[0074] As a preferred embodiment of this utility model, such as Figure 4As shown, the central area of ​​the heating plate 3 is provided with an opening 32 for the temperature control element 4 to extend out, and the projection of the raised portion 23 toward the heating plate 3 is at least partially located within the opening 32.

[0075] At least a portion of the raised portion 23 corresponds vertically to the opening 32, so that the heat insulation gap 24 is connected to the opening 32. Therefore, the heat gathered in the heat insulation gap 24 can be dissipated through the opening 32, so that the central area of ​​the bottom wall of the inner liner 2 can dissipate heat in time, and avoid the heat from accumulating in large quantities in the mating plane 21 and the heat insulation gap 24, which would affect the detection accuracy of the temperature control element 4.

[0076] Preferably, such as Figure 4 As shown, the temperature control element 4 passes through the opening 32, and there is an overheating gap between the outer periphery of the temperature control element 4 and the edge of the opening 32, so that the heat in the heat insulation gap 24 can be dissipated downward through the overheating gap.

[0077] As a preferred option, such as Figure 3 As shown, a heating tube 31 is embedded inside the heating plate 3, and the projection of the heating tube 31 toward the inner liner 2 is located on the fitting arc surface 22.

[0078] The heating element 31 serves as the heat source for the heating plate 3 and is positioned vertically opposite to the contact arc surface 22. This allows the heat generated by the heating element 31 to be transferred to the contact arc surface 22 as much as possible through the heat transfer arc surface of the heating plate 3, ensuring full contact between the area of ​​the heating plate 3 near the heating element 31 and the inner liner 2, thus guaranteeing the heating effect. Simultaneously, the raised portion 23 is located inside the heating element 31 and is offset vertically from it, meaning the outer edge of the raised portion 23 is located inside the inner edge of the heating element 31 (the side closer to the center of the inner liner 2). This also reduces the heat radiated to the raised portion 23, preventing excessive temperature rise at the raised portion 23 and the contact surface 21.

[0079] Furthermore, such as Figure 3 As shown, the heating plate 3 has a downwardly protruding mounting protrusion 33, and the heating tube 31 is embedded inside the mounting protrusion 33. The outer edge of the protrusion 23 is flush with the inner edge of the mounting area, or is located on the inner side of the inner edge of the mounting area (the side closer to the center of the inner liner 2).

[0080] As a preferred embodiment of this utility model, such as Figure 4 As shown, the raised portion 23 includes a top wall 232 and transition sections 235 located on both sides of the top wall 232. The heat insulation gap 24 includes a first gap between the top wall 232 and the heating plate 3, and a second gap between the transition section 235 and the heating plate 3. The first gap is no greater than 5mm.

[0081] If the first gap is too large, it will affect the fit between the bottom wall of the inner pot 2 and the heating plate 3, resulting in a decrease in the heat transfer efficiency from the heating plate 3 to the inner pot 2. The first gap should not be greater than 5mm. This can ensure the heat insulation effect of the heat insulation gap 24 and reduce the radiation of heat to the mating surface 21, while ensuring the contact effect between the heating plate 3 and the bottom wall of the inner pot 2, and ensuring the heating effect on the food.

[0082] Preferably, such as Figure 4 As shown, the protrusion height of the raised portion 23 relative to the mating plane 21 is H, where H≤5mm.

[0083] If the protrusion height of the raised portion 23 is too high, it will not only fail to effectively improve the structural strength of the bottom wall of the inner liner 2, but will also adversely affect the strength of the inner liner 2. At the same time, if the step differences between different areas of the bottom wall of the inner liner 2 are too large, it will also make subsequent polishing and other processing difficult. The protruding portion 23 can not only effectively improve the structural strength of the bottom wall of the inner liner 2, but also, with a protrusion height of no more than 5mm, prevent the bottom wall of the inner liner 2 from having large-scale unevenness, thereby facilitating subsequent polishing and reducing processing difficulty.

[0084] Preferably, such as Figure 2 , Figure 4 As shown, transition surfaces are provided between the raised portion 23 and the mating plane 21, as well as between the raised portion 23 and the mating arc surface 22.

[0085] The inner and outer sides of the raised portion 23 are both curved, making the connection between the raised portion 23 and the mating plane 21 and the mating arc surface 22 more rounded, avoiding the formation of corners, thus preventing food from accumulating in the corners and the inconvenience of cleaning. At the same time, it also facilitates polishing and reduces the difficulty of the process.

[0086] It should be noted that the transition surface can be a circular arc, a sloping surface, or other irregular curved surfaces to improve aesthetics, as long as the transition between the raised part 23 and the mating plane 21 and the mating arc surface 22 is smoother and there are no obvious corners. There are no restrictions here.

[0087] In a preferred embodiment, such as Figure 4 As shown, the diameter of the contact plane 21 is D1, and the top of the temperature control element 4 has a contact plane with a diameter of D2, where D1 > D2.

[0088] The diameter of the contact surface 21 is larger than the diameter of the contact surface at the top of the temperature control element 4. This not only ensures that the temperature control element 4 and the contact surface 21 are in full contact, making the temperature measurement more accurate, but also allows for a certain margin to compensate for the misalignment of the inner liner 2. Even if the inner liner 2 is slightly offset relative to the heating plate 3, that is, the center line of the inner liner 2 is slightly misaligned with the center line of the heating plate 3, it can still ensure that the contact surface can make contact with the contact surface 21, thereby accurately measuring the temperature of the inner liner 2.

[0089] As a preferred embodiment of this utility model, such as Figure 7 As shown, the bottom of the side wall of the inner liner 2 is provided with heat-retaining ridges 25. The heat-retaining ridges 25 are arranged at intervals along the circumference of the inner liner 2 and extend upward in a spiral shape.

[0090] The heat-retaining ridges 25 create an uneven surface on the bottom sidewall of the inner pot 2, which facilitates heat accumulation. Furthermore, the ridges increase the surface area of ​​the inner pot 2's sidewall, thereby increasing the heat transfer area and allowing more heat to be transferred to the sidewall and ultimately to the food inside. This improves the heating effect on the food at the bottom of the inner pot 2's sidewall, resulting in more even heating and better cooking. Simultaneously, the spiral shape of the ridges 25 helps heat flow upwards from the periphery of the inner pot 2, extending the heat flow path and increasing the contact time between the heat and the food inside, further enhancing the heating effect.

[0091] Multiple heat-gathering ridges 25 form a spiral heat channel extending from bottom to top on the side wall of the inner pot 2. This allows the heat at the bottom of the inner pot 2 to be guided by the heat-gathering ridges 25 and flow upwards along the side wall of the inner pot 2 within the heat channel. This improves the efficiency of heat transfer from the bottom of the inner pot 2 upwards, allowing the upper food to heat up faster, improving the uniformity of heating between the upper and lower food layers, and increasing heating efficiency.

[0092] For any parts not mentioned in this utility model, existing technologies can be used or referenced.

[0093] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0094] The above description is merely an embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this utility model should be included within the scope of the claims of this utility model.

Claims

1. An electric cooking appliance comprising an outer pot, an inner pot arranged in the outer pot, and a heating plate arranged between the bottom of the outer pot and the inner pot, wherein the outer pot further comprises a temperature control element which is in contact with the bottom surface of the inner pot, characterized in that the bottom surface of the inner pot comprises a fitting arc surface which is in contact with the heating plate and a fitting flat surface which is in contact with the temperature control element, and a raised portion is arranged between the fitting arc surface and the fitting flat surface, and a heat insulation gap is formed between the raised portion and the heating plate.

2. The electric cooking appliance according to claim 1, characterized in that the fitting flat surface is arranged in the central region of the bottom surface of the inner pot, the fitting arc surface is arranged around the outer periphery of the fitting flat surface, the outer periphery of the fitting flat surface is surrounded by a raised rib, and the raised rib constitutes the raised portion.

3. The electric cooking appliance according to claim 2, characterized in that the raised rib and the fitting flat surface are connected by a first transition arc surface, the raised rib and the fitting arc surface are connected by a second transition arc surface, and the curvature of the first transition arc surface is greater than the curvature of the second transition arc surface.

4. The electric cooking appliance according to claim 1, characterized in that the central region of the heating plate is provided with an opening for the temperature control element to extend out of, and the projection of the raised portion towards the heating plate is at least partially located in the opening.

5. The electric cooking appliance according to claim 1, characterized in that a heating tube is embedded in the heating plate, and the projection of the heating tube towards the inner pot is located on the fitting arc surface.

6. The electric cooking appliance according to claim 1, characterized in that the raised portion comprises a top wall and transition sections on both sides of the top wall, the heat insulation gap comprises a first gap between the top wall and the heating plate and a second gap between the transition sections and the heating plate, and the first gap is not greater than 5 mm.

7. The electric cooking appliance according to claim 1, characterized in that the raised portion protrudes from the fitting flat surface by a height H, and H≤5 mm.

8. The electric cooking appliance according to claim 1, characterized in that the inner pot is a single-layer plate structure, and the wall thickness of the inner pot is not greater than 0.7 mm.

9. The electric cooking appliance according to claim 1, characterized in that the diameter of the fitting flat surface is D1, the top of the temperature control element has a contact flat surface, the diameter of the contact flat surface is D2, and D1>D2.

10. The electric cooking appliance according to claim 1, characterized in that the bottom of the side wall of the inner pot is provided with heat gathering ribs, the heat gathering ribs are arranged at intervals along the circumference of the inner pot, and extend upwards in a spiral shape. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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