A zonally heatable electromagnetic cooking appliance

Abstract

The utility model discloses a kind of electromagnetic cooking utensils of partitionable heating, including control module, inner bag and the electromagnetic wire disc placed in the lower part of inner bag, inner bag has arc transition portion between bottom and side, electromagnetic wire disc includes disc body, disc body has bottom wall, vertical wall and the arc portion of both, arc portion is around with first line group, first line group extends to vertical wall from arc portion, bottom wall is around with second line group, second line group is below first line group, first line group and second line group are electrically connected with control module respectively.Second line group extends to the upper edge of disc body from arc portion, increase the coverage area of second line group on disc body surface, thereby improve the heating area of inner bag side, not only form effective temperature gradient in vertical direction, but also form effective temperature gradient in inner bag inside, inside and outside, help to promote liquid formation including up and down and inside and outside convection, so that heat distribution is more uniform.

Description

Technical Field

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

[0002] Induction heating (IH) technology utilizes the principle of electromagnetic induction, generating an alternating magnetic field through a coil to heat the cookware. Due to its high heating efficiency and rapid temperature rise, it has become a core technology in modern cooking appliances. The winding structure of its core component, the coil, directly affects the uniformity of the magnetic field distribution and heating efficiency. Currently, the coil structures and designs in commercially available cooking appliances have certain limitations, hindering improvements in heating efficiency.

[0003] Common coil layouts often involve single-area coverage, such as the coil only winding around the bottom of the coil. During operation, the bottom coil heats the bottom of the pot, concentrating the heat at the bottom. This results in a limited heating area and extremely uneven heating of the pot and its contents, leading to localized overheating and burning, or localized underheating and undercooked food. Furthermore, this heating method fails to create an effective temperature gradient within the pot, thus preventing convection (the spontaneous circulation of liquids or gases due to temperature differences) and further contributing to the uneven heat distribution.

[0004] Therefore, in existing technologies, some products also have coils wound on the side of the coil. However, the position, coverage area, and number of turns of the side coils are often poorly designed compared to the bottom coils, resulting in poor heating of the sides of the pot. Heat is concentrated at the bottom of the pot, creating a significant temperature difference in the vertical direction of the food (higher temperature at the bottom, lower temperature at the top), allowing for convection. However, this convection is primarily vertical, failing to achieve internal and external convection (convection at the center and edges), resulting in poor heat uniformity. Furthermore, the uneven heating of the pot by the coil causes localized convection within the pot, leading to poor heat exchange and potentially loud noise, failing to create convection that covers the entire pot. Utility Model Content

[0005] This invention provides an electromagnetic cooking appliance with zoned heating to solve the problem that existing coils, due to the limitations of their winding structure, cannot effectively create a convection effect covering the entire area inside the pot, and the convection method is singular, resulting in poor heating effect and uniformity of the food inside the pot.

[0006] The technical solution adopted in this utility model is as follows:

[0007] An electromagnetic cooking appliance with zoned heating includes a control module, an inner pot, and an electromagnetic coil placed below the inner pot. The inner pot has an arc-shaped transition section between the bottom and the side. The electromagnetic coil includes a body with a bottom wall, a vertical wall, and an arc-shaped section between the bottom wall and the vertical wall. A first wire group is wound around the surface of the arc-shaped section, extending from the arc-shaped section to the vertical wall. A second wire group is wound around the bottom wall, located below the first wire group. The first wire group and the second wire group are electrically connected to the control module.

[0008] In this invention, the first wire group forms a magnetic field at the bottom of the inner liner after being energized, which is used to heat the bottom of the inner liner. The second wire group forms a magnetic field at the side of the inner liner and the arc-shaped transition part after being energized, which is used to heat the side of the inner liner. The second heating element extends from the curved section to the upper edge of the plate, i.e., the vertical wall, increasing its coverage area on the plate surface and thus improving the heating area on the side of the inner pot. This not only creates an effective temperature gradient in the vertical direction but also an effective temperature gradient on the inside and outside of the food inside the inner pot. This helps promote convection of the liquid inside the inner pot in both vertical and horizontal directions, allowing the food in all areas of the inner pot to move up and down and in and out according to a more uniform convection pattern. During this process, the food rolls and moves 360° without dead angles on the inside, outside, and top and bottom of the inner pot, making the heat distribution inside the inner pot more even, improving heating uniformity and cooking taste. In addition, the first and second heating elements are wound independently, allowing them to work together or independently, achieving "dual drive" of the two heating elements. This allows for precise control of the convection pattern inside the inner pot or alternation of multiple convection patterns to further improve heating uniformity.

[0009] Specifically, when the first heating element is working, the liquid at the vertical wall of the inner liner is heated and flows horizontally from the perimeter of the inner liner towards its center. The liquid at the curved section of the inner liner is heated and flows upwards while simultaneously flowing towards the center, i.e., it flows upwards at an angle. This upward flow is obstructed by the horizontally flowing liquid above, causing it to tumble and flow downwards from the center of the inner liner. This collision between the liquid heated by the first heating element on the vertical wall and the liquid heated by the first heating element on the curved section enhances the tumbling and agitation of the liquid flow inside the inner liner. Both liquid flows then sink together from the center of the inner liner, thus forming a convection circulation.

[0010] The first thread group covers a larger area on the disk surface than the second thread group.

[0011] In this design, the first wire group has a larger coverage area than the second wire group. The increased coverage area results in a stronger magnetic field formed by the first wire group, which in turn improves the heating effect on the side of the inner pot. This causes the food temperature on the outer side (closer to the inner pot side, i.e., the edge of the inner pot) to be higher, while the food temperature on the inner side (far from the inner pot side, i.e., the center of the inner pot) is lower. This creates an effective temperature gradient between the inner and outer sides, promoting strong convection between the inner and outer food, significantly improving heating uniformity, and allowing for more complete release of nutrients from the food.

[0012] The first coil group includes a first coil wound on the arc-shaped part and a second coil wound on the vertical wall. The first coil is wound in a double-layer structure on the surface of the arc-shaped part, and the second coil is wound in a single-layer structure on the surface of the vertical wall.

[0013] In this design, the first coil is stacked as a double-layer coil at the arc-shaped section. The magnetic fields of the two layers of coils can be superimposed, resulting in a stronger magnetic field at the arc-shaped section. Food tends to concentrate there more easily as it gets closer to the bottom, which can specifically improve the heating effect on the arc-shaped transition area of ​​the inner pot. This concentrates more heat at the junction of the bottom and sides of the inner pot. Since the first coil at the arc-shaped section is closer to the second coil on the bottom wall, the double-layer winding here can balance the magnetic field at the junction of the side and bottom magnetic fields, reducing magnetic field fluctuations. The vertical wall area, corresponding to less food in the inner pot, is heated by the independent magnetic field formed by the single-layer first coil. This makes the heat distribution more compatible with the distribution of food, improving the rationality of heat distribution and helping to save costs while ensuring heating efficiency.

[0014] The first coil includes a first inner coil and a first outer coil. The number of turns of the first inner coil is greater than the number of turns of the first outer coil, so that the surface of the arc-shaped portion has an overlapping heating area where the first inner coil and the first outer coil coincide, and an isolated heating area where the first inner coil and the first outer coil are misaligned.

[0015] In this scheme, the first inner coil and the first outer coil are each considered as current-carrying coils composed of countless current elements. When the inner and outer coils are staggered, the magnetic induction intensity generated by each current element in space is synthesized according to the principle of vector superposition. The central coil of the first inner coil is the region with a relatively strong magnetic induction intensity (heating ring) generated by the current elements, and the central coil of the first outer coil is also the region with a relatively strong magnetic induction intensity (heating ring). They are partially staggered and partially overlapped in the height direction, causing the total heating ring to extend in the height direction. In the overlapping region, the magnetic induction intensity is the superposition of the magnetic induction induction intensity generated by each coil layer, forming a strong magnetic field; in the staggered region, each coil layer still has a portion of its own heating ring, thus maintaining a relatively strong magnetic induction intensity. At this point, the total heating ring area is the sum of the heating ring areas of the inner and outer coils minus the area of ​​the overlapping heating ring. Compared to a scheme where the two heating rings completely overlap, this significantly increases the total area of ​​the side heating rings, which is also the height of the side heating rings. This increases the heating area on the sides of the cookware, allowing a larger area of ​​the sides to be covered by the heating rings. This improves the uniformity of heating on the sides of the cookware, resulting in more even heating of food on the bottom and sides, and improving the taste of the cooked food. At the same time, the larger heating area allows for a reduction in heating power or heating time, helping to lower energy consumption.

[0016] The second coil is wound in a double layer on the surface of the bottom wall, having a second inner coil and a second outer coil. The number of turns of the second inner coil is greater than the number of turns of the second outer coil, so that the distance between the second inner coil and the first inner coil is less than the distance between the second outer coil and the first outer coil.

[0017] In this design, the effective superposition of magnetic fields is achieved based on the Biot-Savart law. The total heating ring area at the bottom of the electromagnetic coil is the sum of the heating ring areas of the second inner coil and the second outer coil, minus the area of ​​the overlapping heating ring. This significantly increases the width of the total heating ring at the bottom. Under the same heating power, the increased heating area results in a more uniform heat distribution at the bottom of the pot, reducing the temperature difference between the center and edge areas. Furthermore, the smaller distance between the second and first inner coils allows for partial overlap between the bottom and side magnetic fields. This balances the magnetic field strength at the interface between the side and bottom magnetic fields, reducing magnetic field fluctuations and further enhancing the heating effect at the interface. This improves the overall heating uniformity of the inner pot and reduces the rate of scorching.

[0018] A winding gap is provided between the arc-shaped part and the vertical wall, and a fixing lug for fixing the magnetic strip frame is provided in the winding gap.

[0019] In this design, the fixing lug is positioned between the curved section and the vertical wall, where there is a winding gap—meaning the first wire group does not cover this area. This provides installation space for the fixing lug, preventing interference between it and the first wire group. Consequently, it does not affect the winding neatness of the first wire group, contributing to the formation of a stable and reliable magnetic field. Furthermore, the structural strength at the junction of the curved section and the vertical wall is higher than that of a single plane, increasing stability after the fixing lug is installed. This ensures a stable coupling gap between the first wire group and the inner liner, further reducing magnetic field fluctuations.

[0020] The electromagnetic cooking appliance is equipped with a first drive unit and a second drive unit. The first wire group is electrically connected to the control module through the first drive unit, and the first drive unit is used to control the operation of the first wire group. The second wire group is electrically connected to the control module through the second drive unit, and the second drive unit is used to control the operation of the second wire group.

[0021] In this design, the first and second heating wire groups are controlled by independent control units, allowing them to work together or independently. This enables targeted heating of the bottom or sides of the inner pot, precisely adjusting the heating state according to different stages of cooking. For example, during the water absorption stage of steaming rice, the first heating wire group on the side can be activated alone for low-power heating; during the boiling stage, both the first and second heating wire groups can be activated simultaneously for high-power heating; and during the simmering stage, the second heating wire group at the bottom can be activated alone for heat preservation. This flexible control method significantly improves cooking results and enhances the taste of the food.

[0022] The control module includes a main control unit and a switching unit. The first and second wire groups are electrically connected to the switching unit, and the switching unit is configured to enable the main control unit to jointly control or separately control the operation of the first and second wire groups.

[0023] In this scheme, the first and second wire groups are connected in parallel with the main control unit. The main control unit can be selectively connected to either one or both wire groups by switching the switching unit, satisfying the requirement for the first and second wire groups to work together or independently. Furthermore, this scheme has a simpler circuit structure, lower cost, and more stable reliability.

[0024] The first and second line groups work alternately.

[0025] In this design, when the second heat exchanger is operating, the temperature at the bottom of the inner liner is higher, with the highest temperature at the bottom center. This temperature difference causes the liquid at the bottom center to flow upwards, the liquid at the top center to flow outwards, and the liquid at the top edge to flow towards the bottom of the inner liner, creating convection from the inside out. When the first heat exchanger is operating, the temperature on the sides of the inner liner is higher, causing the hot liquid to flow upwards, from the top towards the center of the inner liner, then from the center towards the bottom, and finally outwards, creating convection from the outside in. The alternating operation of the two heat exchangers allows the liquid inside the inner liner to undergo these two types of flow alternately, resulting in a more even distribution of heat throughout the inner liner.

[0026] The arc-shaped portion is provided with first pressure ribs at intervals along the circumference of the disc body. The first pressure ribs and the arc-shaped portion form a first winding space for winding the first wire group. The bottom wall is provided with second pressure ribs at intervals along the circumference of the disc body, as well as a planar winding area. The second pressure ribs and the planar winding area form a second winding space for winding the second wire group. The number of first pressure ribs is not less than the number of second pressure ribs.

[0027] In this design, the bottom wall of the disc has a planar winding area. Winding the second wire group on this planar surface is simpler and more stable. A smaller number of second pressure ribs are sufficient to stably confine the second wire group within the planar winding area. However, the surface of the curved section is arc-shaped, making winding the first wire group more difficult and prone to loosening after winding. Therefore, a larger number of first pressure ribs confine the first wire group within the curved section. Furthermore, since the diameter of the first wire group is larger than that of the second wire group, a greater number of first pressure ribs increases the confinement area for the first wire group, ensuring its regularity. Attached Figure Description

[0028] 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:

[0029] Figure 1 This is a cross-sectional view of an electromagnetic coil according to one embodiment of the present invention.

[0030] Figure 2 for Figure 1 A magnified view of area A in the middle;

[0031] Figure 3 for Figure 1 A magnified view of area B in the middle;

[0032] Figure 4 This is a schematic diagram of the structure of an electromagnetic coil according to one embodiment of the present invention;

[0033] Figure 5 for Figure 4 A schematic diagram of the structure of the electromagnetic coil from another perspective;

[0034] Figure 6 This is a schematic diagram of the structure of the disc body according to one embodiment of the present invention;

[0035] Figure 7 This is a cross-sectional view of a portion of the structure of an electromagnetic cooking appliance according to one embodiment of the present invention, wherein the arrows indicate the direction of liquid flow;

[0036] Figure 8 This is a cross-sectional view of a portion of the electromagnetic cooking appliance according to another embodiment of the present invention, wherein the arrows indicate the direction of liquid flow.

[0037] in:

[0038] 1. Electromagnetic coil; 11. Coil body; 111. Bottom wall; 112. Arc-shaped part; 113. Vertical wall; 1131. Wire separator rib; 1132. Winding groove; 114. Fixing lug; 115. Planar winding area; 12. First wire group; 121. First inner coil; 122. First outer coil; 123. First coil; 124. Second coil; 13. Second wire group; 131. Second inner coil; 132. Second outer coil; 14. First pressure rib; 15. Second pressure rib; 16. Isolation rib; 17. Overlapping heating area; 18. Isolated heating area; 19. Winding gap;

[0039] 2. Inner liner. Detailed Implementation

[0040] To more clearly illustrate the overall concept of this utility model, a detailed description will be provided below with reference to the accompanying drawings.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] like Figure 1 , Figure 4 , Figure 5 As shown, an electromagnetic cooking appliance with zoned heating includes a control module, an inner pot 2, and an electromagnetic coil 1 located below the inner pot 2. The inner pot 2 has an arc-shaped transition portion between the bottom and the side. The electromagnetic coil 1 includes a body 11, which has a bottom wall 111, a vertical wall 113, and an arc-shaped portion 112 located between the bottom wall 111 and the vertical wall 113. A first wire group 12 is wound around the surface of the arc-shaped portion 112, extending from the arc-shaped portion 112 to the vertical wall 113. A second wire group 13 is wound around the bottom wall 111, located below the first wire group 12. The first wire group 12 and the second wire group 13 are electrically connected to the control module.

[0046] In this invention, when the first wire group 12 is energized, a magnetic field is formed at the bottom of the inner liner 2 to heat the bottom of the inner liner 2. When the second wire group 13 is energized, a magnetic field is formed at the side of the inner liner 2 and at the arc-shaped transition part to heat the side of the inner liner 2. The second heating element 13 extends from the arc-shaped portion 112 to the upper edge of the plate body 11, i.e., the vertical wall 113, increasing the coverage area of ​​the second heating element 13 on the surface of the plate body 11. This increases the heating area on the side of the inner pot 2, thus creating an effective temperature gradient not only in the vertical direction but also on the inner and outer sides of the food inside the inner pot 2. This helps to promote the formation of convection in the liquid inside the inner pot 2, including vertical and horizontal convection, allowing the food in each area of ​​the inner pot 2 to move up and down and in and out according to a more uniform convection pattern. During this process, the food rolls and moves 360° without dead angles on the inner and outer sides and the upper and lower sides of the inner pot 2, making the heat distribution inside the inner pot 2 more uniform, improving heating uniformity and cooking taste. In addition, the first wire group 12 and the second wire group 13 are wound independently, so that the first wire group 12 and the second wire group 13 can work together or work independently, realizing the "dual drive" of the two wire groups. That is, the cooking appliance can drive the two wire groups to work independently. This further enables precise control of the convection mode inside the inner pot 2, or allows multiple convection modes to alternate, so as to further improve the heating uniformity.

[0047] Specifically, such as Figure 8 As shown, when the first heating element 12 is working, the liquid at the vertical wall 113 of the inner liner 2 is heated and flows horizontally from the periphery of the inner liner 2 towards its center. The liquid at the arc-shaped portion 112 of the inner liner 2 is also heated and flows upwards while simultaneously flowing towards its center, i.e., it flows upwards at an angle. This liquid is obstructed by the horizontally flowing liquid above, causing it to tumble and flow downwards from the center of the inner liner 2. Therefore, the two liquids heated by the first heating element 12 on the vertical wall 113 and the first heating element 12 on the arc-shaped portion 112 collide, enhancing the tumbling and dancing effect of the liquid flow inside the inner liner 2. The two liquid flows sink together from the center of the inner liner 2, thus forming a convection circulation.

[0048] It is understood that this utility model does not limit the cooking type of the cooking appliance. Preferably, it is a multi-functional cooking appliance, that is, it can perform various cooking methods such as steaming rice, cooking porridge, and stewing meat. Therefore, this utility model does not limit the ingredients inside the inner pot 2. It can be rice, meat, or any type of food.

[0049] Preferably, a temperature measuring component is provided at the center of the bottom wall 111 of the plate body 1, and the second wire group 13 surrounds the outer periphery of the temperature measuring component. The temperature measuring component can detect the temperature of the inner pot 2 in real time, providing a basis for heating control. This helps to associate the temperature of the inner pot 2 with the control program of the cooking appliance, so that the control unit can accurately control the working mode of the first wire group 12 and the second wire group 13 under different working conditions, thereby making the liquid inside the inner pot 2 form a specific convection mode to meet different cooking needs.

[0050] In addition, since the bottom and side of the inner liner 2 have an arc-shaped transition section, the arc-shaped transition section can also guide the internal and external convection and vertical convection of the internal liquid, thereby accelerating the formation of convection.

[0051] As a preferred embodiment of this utility model, such as Figure 4 , Figure 5 As shown, the coverage area of ​​the first line group 12 on the surface of the disk body 11 is greater than the coverage area of ​​the second line group 13 on the surface of the disk body 11.

[0052] The first wire group 12 has a larger coverage area than the second wire group 13. The increased coverage area results in a stronger magnetic field formed by the first wire group 12, which in turn improves the heating effect on the side of the inner pot 2. This causes the food temperature on the outer side (closer to the side of the inner pot 2, i.e., the edge of the inner pot 2) to be higher, while the food temperature on the inner side (far from the side of the inner pot 2, i.e., the center of the inner pot 2) is lower. This creates an effective temperature gradient between the inner and outer sides, promoting strong convection between the inner and outer food, significantly improving heating uniformity, and allowing for more complete release of nutrients from the food.

[0053] Preferably, the area covered by the first thread group 12 of the inner liner 2 is 300-650 cm², and the area covered by the second thread group 13 of the inner liner 2 is 100-300 cm². 2 The coverage area of ​​the first line group 12 is 200-350cm larger than that of the second line group 13. 2 .

[0054] Experiments showed that when the traditional heating coil heats the inner pot 2, the temperature difference between the inner and outer food parts can reach 15℃-20℃, affecting nutrient release and resulting in a nutrient release rate of only 60%-65%. However, with the electromagnetic coil 1 of this invention, the temperature difference between the inner and outer parts of the food inside the inner pot 2 is reduced to 5℃-8℃, a reduction of 60%-70% compared to the traditional structure. Heating uniformity is significantly improved, and the nutrient release rate increases from 60%-65% to 85%-90%.

[0055] In a preferred embodiment, such as Figure 4 , Figure 5As shown, the first coil group 12 includes a first coil 123 wound on the arc-shaped portion 112 and a second coil 124 wound on the vertical wall 113. The first coil 123 is wound in a double-layer structure on the surface of the arc-shaped portion 112, and the second coil 124 is wound in a single-layer structure on the surface of the vertical wall 113.

[0056] The first coil 123 is stacked as a double-layer coil at the arc-shaped section 112. The magnetic fields of the two layers of coils can be superimposed, resulting in a stronger magnetic field at the arc-shaped section 112. Food tends to concentrate closer to the bottom, which can specifically improve the heating effect on the arc-shaped transition area of ​​the inner pot 2. This concentrates more heat at the junction of the bottom and sides of the inner pot 2. Since the first coil 123 at the arc-shaped section 112 is closer to the second coil 124 on the bottom wall 111, the double-layer winding here can balance the magnetic field at the junction of the side magnetic field and the bottom magnetic field, reducing magnetic field fluctuations. The vertical wall 113 corresponds to the inner pot 2 with less food. Heating is achieved by the magnetic field independently formed by the single layer of the first coil 123, which makes the heat distribution more compatible with the distribution of food, improving the rationality of heat distribution and helping to save costs while ensuring heating efficiency.

[0057] Preferably, such as Figure 6 As shown, the vertical wall 113 is provided with a plurality of spacer ribs 1131 arranged at intervals along the height direction of the disk body 111. A winding groove 1132 is formed between adjacent spacer ribs 1131. The single wire of the second coil 124 is located in the winding groove 1132 so that the upper and lower coils of wire do not contact each other, forming a loose winding structure.

[0058] Furthermore, such as Figure 2 As shown, the first coil 123 includes a first inner coil 121 and a first outer coil 122. The number of turns of the first inner coil 121 is greater than the number of turns of the first outer coil 122, so that the surface of the arc-shaped portion 112 has an overlapping heating area 17 where the first inner coil 121 and the first outer coil 122 overlap, and an isolated heating area 18 where the first inner coil 121 and the first outer coil 122 are misaligned.

[0059] The first inner coil 121 and the first outer coil 122 can be considered as current-carrying coils composed of countless current elements. When the inner and outer coils are staggered, the magnetic induction intensity generated by each current element in space is synthesized according to the principle of vector superposition. The central coil of the first inner coil 121 is the region with a relatively strong magnetic induction intensity (heating ring) generated by the current element, and the central coil of the first outer coil 122 is also the region with a relatively strong magnetic induction intensity (heating ring). They are partially staggered and partially overlapped in the height direction, causing the total heating ring to extend in the height direction. In the overlapping region, the magnetic induction intensity is the superposition of the magnetic induction intensities generated by the two coils, forming a strong magnetic field; in the staggered region, each coil still has a portion of its own heating ring, thus maintaining a relatively strong magnetic induction intensity. At this point, the total heating ring area is the sum of the heating ring areas of the inner and outer coils minus the area of ​​the overlapping heating ring. Compared to a scheme where the two heating rings completely overlap, this significantly increases the total area of ​​the side heating rings, which is also the height of the side heating rings. This increases the heating area on the sides of the cookware, allowing a larger area of ​​the sides to be covered by the heating rings. This improves the uniformity of heating on the sides of the cookware, resulting in more even heating of food on the bottom and sides, and improving the taste of the cooked food. At the same time, the larger heating area allows for a reduction in heating power or heating time, helping to lower energy consumption.

[0060] like Figure 2 As shown, the arc-shaped portion 112 is provided with a first pressure rib 14, and there is an isolation rib 16 between the pressure rib and the surface of the arc-shaped portion 112. The first inner coil 121 is wound between the isolation rib 16 and the surface of the arc-shaped portion 112, and the first outer coil 122 is wound between the isolation rib 16 and the first pressure rib 14.

[0061] Preferably, the first inner coil 121 has 10-20 turns, and the first outer coil 122 has 5-18 turns. The inner and outer coils are staggered, with a stagger distance of 4mm-10mm.

[0062] Experiments have shown that single-layer winding or non-misaligned double-layer winding structures result in a central heating ring width of only 20mm-25mm, leading to a small and concentrated heating area. Under the same heating power, the inner pot 2 experiences excessively high local temperatures, easily causing scorching, with a scorching rate as high as 8%-10%. In this embodiment, the first coil 123 is double-layered with misaligned winding, and the inner coil has more turns than the outer coil, increasing the total width of the heating ring (in the height direction of the inner pot 2) to 50mm-55mm, an increase of 100%-120% compared to the traditional structure. Under the same heating power, the increased heating area, combined with the Biot-Savart law, results in a more uniform magnetic field distribution.

[0063] Preferably, such as Figure 3As shown, the second coil group 13 is wound in a double layer on the surface of the bottom wall 111, and has a second inner coil 131 and a second outer coil 132. The number of turns of the second inner coil 131 is greater than the number of turns of the second outer coil 132, so that the distance between the second inner coil 131 and the first inner coil 121 is less than the distance between the second outer coil 132 and the first outer coil 122.

[0064] Based on the Biot-Savart law, the magnetic fields are effectively superimposed. The total heating ring area at the bottom of the electromagnetic coil 1 is the sum of the heating ring areas of the second inner coil 131 and the second outer coil 132, minus the area of ​​the overlapping heating ring. This significantly increases the width of the total heating ring at the bottom. Under the same heating power, the increased heating area makes the heat distribution at the bottom of the pot more uniform, reducing the temperature difference between the center and edge areas of the pot. Furthermore, the smaller distance between the outer ring of the second inner coil 131 and the inner ring of the first inner coil 121 allows for partial overlap between the bottom and side magnetic fields. This balances the magnetic field strength at the interface between the side and bottom magnetic fields, reduces magnetic field fluctuations, further enhances the heating effect at the interface between the bottom and side magnetic fields, improves the overall heating uniformity of the inner pot 2, and reduces the rate of scorching.

[0065] Experiments have shown that the magnetic field strength fluctuation at the junction of the bottom magnetic field and the side magnetic field is controlled at 5%-8%, which is 70%-80% lower than the 25%-30% of the traditional structure. This effectively avoids local overheating, making it less likely for rice to stick to the pot, and reducing the sticking rate from 8%-10% to 1%-2%.

[0066] Preferably, such as Figure 2 As shown, the inner coils of the first inner coil 121 and the first outer coil 122 are flush to form an overlapping heating area 17. Their outer coils are misaligned to form an isolated heating area 18, so that the isolated heating area 18 is located above the overlapping heating area 17 and away from the center of the disk body 11. Similarly, the inner coils of the second inner coil 131 and the second outer coil 132 are flush to form an overlapping heating area 17. Their outer coils are misaligned to form an isolated heating area 18, so that the isolated heating area 18 is located on the outer periphery of the overlapping heating area 17 and away from the center of the disk body 11.

[0067] In a preferred embodiment, such as Figure 5 As shown, a winding gap 19 is provided between the arc-shaped portion 112 and the vertical wall 113, and a fixing lug 114 for fixing the magnetic strip frame is provided in the winding gap 19.

[0068] The fixing lug 114 is positioned between the arc-shaped portion 112 and the vertical wall 113, where there is a winding gap 19, meaning the first wire group 12 does not cover this area. This provides installation space for the fixing lug 114, ensuring that it does not interfere with the first wire group 12 and thus does not affect the winding neatness of the first wire group 12, contributing to the formation of a stable and reliable magnetic field. Furthermore, the structural strength at the junction of the arc-shaped portion 112 and the vertical wall 113 is higher than that of a single plane, increasing the stability after the fixing lug 114 is installed. This ensures a stable coupling gap between the first wire group 12 and the inner liner 2, further reducing magnetic field fluctuations.

[0069] Preferably, such as Figure 5 As shown, a winding gap 19 is also provided between the first wire group 12 and the second wire group 13.

[0070] Preferably, in this invention, the first wire group 12 and the second wire group 13 are independently wound on the disc body 11, and each is connected to an independent control circuit and power module, which can realize independent heating control of the bottom second wire group 13 and the side first wire group 12, that is, the bottom and the side can be heated independently or simultaneously. Preferably, the heating power range of the first wire group 12 is 900W-1300W, and the heating power range of the second wire group 13 is 600W-900W.

[0071] However, this utility model does not limit the control method of the first wire group 12 and the second wire group 13, and it can be one of the following embodiments:

[0072] Example 1: In this example, the electromagnetic cooking appliance is provided with a first driving unit and a second driving unit. The first wire group 12 is electrically connected to the control module through the first driving unit, and the first driving unit is used to control the operation of the first wire group 12. The second wire group 13 is electrically connected to the control module through the second driving unit, and the second driving unit is used to control the operation of the second wire group 13.

[0073] Specifically, in this embodiment, two sets of IGBT resonant circuits are used for driving. Each circuit includes an IGBT (Insulated Gate Bipolar Transistor), a resonant capacitor, a resonant inductor, and a driver chip. The first wire group 12 connects to the first IGBT resonant circuit, and the second wire group 13 connects to the second IGBT resonant circuit. The control chip adjusts the conduction time of the two IGBTs separately using a pulse width modulation (PWM) signal, achieving independent power regulation for the first wire group 12 and the second wire group 13. When simultaneous heating is required, the two circuits operate independently, with a combined power output of 1400-2200W; when heating individually, only the corresponding circuit operates.

[0074] Example 2: In this example, the control module includes a main control unit and a switching unit. The first line group 12 and the second line group 13 are electrically connected to the switching unit. The switching unit is configured to enable the main control unit to jointly control or separately control the operation of the first line group 12 and the second line group 13.

[0075] Specifically, in this embodiment, a single IGBT resonant circuit (including IGBT and resonant elements) can be used, and the switching of the coil groups can be achieved through two relays (K1, K2). Relay K1 is connected to the first coil group 12, and relay K2 is connected to the second coil group 13. The control chip achieves mode switching by driving the relay contacts to close or open: when K1 is closed, the first coil group 12 is driven alone; when K2 is closed, the second coil group 13 is driven alone; when K1 and K2 are closed simultaneously, the two coils are connected in parallel (total power 1400-2200W). Power adjustment is uniformly controlled by the PWM signal of the IGBT, and the power ratio is fixed when the two coils are working.

[0076] This invention does not limit the working mode of the first wire group 12 and the second wire group 13 during the cooking process. Preferably, the first wire group 12 and the second wire group 13 work alternately.

[0077] When the second wire group 13 is working, the temperature at the bottom of the inner liner 2 is relatively high, and the temperature at the center of the bottom is the highest. Therefore, under the influence of temperature difference, such as Figure 7 As shown, this causes the liquid at the bottom center to flow upwards, the liquid at the top center to flow outwards, and the liquid at the top edge to flow towards the bottom of the inner liner 2, forming convection from the inside out. When the first line group 12 is working, the temperature on the side of the inner liner 2 is higher, such as... Figure 8 As shown, the high-temperature liquid at the vertical wall 113 flows horizontally towards the center of the inner liner, while the high-temperature liquid at the corresponding arc-shaped part 112 flows obliquely upward (upward and towards the center of the inner liner). After the two liquids collide, they tumble violently and then flow together from the center of the inner liner 2 towards the bottom, and from the bottom outward, forming convection from the outside in. The two sets of lines work alternately, allowing the liquid inside the inner liner 2 to alternate between these two flows, making the heat distribution more uniform in all areas inside the inner liner 2.

[0078] Specifically, during the cooking process, the second line group 13 can be made to work for a certain period of time, so that the liquid inside the inner pot 2 can convect from the inside to the outside for a certain period of time. Then, the working state can be switched so that the second line group 13 stops working and the first line group 12 starts working, so that the liquid inside the inner pot 2 can convect from the outside to the inside for a certain period of time. This cycle can be repeated.

[0079] Of course, the first wire group 12 and the second wire group 13 can also work under certain specific cooking conditions, such as the heat preservation stage, where the first wire group 12 works independently and the second wire group 13 does not work, and when heating with high heat, the first wire group 12 and the second wire group 13 work together. No limitation is made here.

[0080] As a preferred embodiment of this utility model, such as Figures 4 to 6 As shown, the arc-shaped portion 112 is provided with first pressure ribs 14 spaced apart along the circumference of the disc body 11. A first winding space for winding the first wire group 12 is formed between the first pressure ribs 14 and the arc-shaped portion 112. The bottom wall 111 is provided with second pressure ribs 15 spaced apart along the circumference of the disc body 11, as well as a planar winding area 115. A second winding space for winding the second wire group 13 is formed between the second pressure ribs 15 and the planar winding area 115. The number of first pressure ribs 14 is not less than the number of second pressure ribs 15.

[0081] The bottom wall 111 of the disc body 11 is provided with a planar winding area 115. Winding the second wire group 13 on the planar surface is simpler and more stable after winding. A smaller number of second pressure ribs 15 are sufficient to stably confine the second wire group 13 within the planar winding area 115. However, the surface of the arc-shaped portion 112 is curved, making winding the first wire group 12 more difficult and prone to loosening after winding. Therefore, a larger number of first pressure ribs 14 confine the first wire group 12 within the arc-shaped portion 112. Furthermore, since the diameter of the first wire group 12 is larger than that of the second wire group 13, a larger number of first pressure ribs 14 increases the confinement area of ​​the first wire group 12, thus maintaining its regularity.

[0082] Specifically, such as Figure 6 As shown, there are 6 first pressure ribs 14 and 5 second pressure ribs 15. Of course, the two can also be other quantities, but the preferred quantity of the first pressure ribs 14 is 5-8.

[0083] For any parts not mentioned in this utility model, existing technologies can be used or referenced.

[0084] 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.

[0085] 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 electromagnetic cooking appliance with zoned heating, comprising a control module, an inner pot, and an electromagnetic coil disposed below the inner pot, the inner pot having an arc-shaped transition portion between the bottom and the side, characterized in that, The electromagnetic coil includes a coil body, which has a bottom wall, a vertical wall, and an arcuate portion located between the bottom wall and the vertical wall. A first wire group is wound around the surface of the arcuate portion, and the first wire group extends from the arcuate portion to the vertical wall. A second wire group is wound around the bottom wall, and the second wire group is located below the first wire group. The first wire group and the second wire group are respectively electrically connected to the control module.

2. The electromagnetic cooking appliance with zoned heating according to claim 1, characterized in that, The first wire group covers a larger area on the surface of the disk than the second wire group covers the same area on the surface of the disk.

3. The electromagnetic cooking appliance with zoned heating according to claim 1, characterized in that, The first coil includes a first coil wound on the arc-shaped portion and a second coil wound on the vertical wall. The first coil is wound in a double-layer structure on the surface of the arc-shaped portion, and the second coil is wound in a single-layer structure on the surface of the vertical wall.

4. The electromagnetic cooking appliance with zoned heating according to claim 3, characterized in that, The first coil includes a first inner coil and a first outer coil. The number of turns of the first inner coil is greater than the number of turns of the first outer coil, so that the surface of the arc-shaped portion has an overlapping heating area where the first inner coil and the first outer coil coincide, and an isolated heating area where the first inner coil and the first outer coil are misaligned.

5. The electromagnetic cooking appliance with zoned heating according to claim 4, characterized in that, The second coil is wound in a double layer on the surface of the bottom wall, having a second inner coil and a second outer coil. The number of turns of the second inner coil is greater than the number of turns of the second outer coil, so that the distance between the second inner coil and the first inner coil is less than the distance between the second outer coil and the first outer coil.

6. The electromagnetic cooking appliance with zoned heating according to claim 1, characterized in that, A winding gap is provided between the arc-shaped portion and the vertical wall, and a fixing lug for fixing the magnetic strip frame is provided in the winding gap.

7. The electromagnetic cooking appliance with zoned heating according to claim 1, characterized in that, The electromagnetic cooking appliance is provided with a first driving unit and a second driving unit. The first wire group is electrically connected to the control module through the first driving unit, and the first driving unit is used to control the operation of the first wire group. The second wire group is electrically connected to the control module through the second driving unit, and the second driving unit is used to control the operation of the second wire group.

8. The electromagnetic cooking appliance with zoned heating according to claim 1, characterized in that, The control module comprises a master control unit and a switching unit, the first wire group and the second wire group are electrically connected with the switching unit respectively, and the switching unit is configured to make the master control unit jointly control or separately control the first wire group and the second wire group to work.

9. The electromagnetic cooking appliance according to claim 7 or 8, wherein The first wire group and the second wire group work alternately.

10. The electromagnetic cooking appliance according to claim 1, wherein The arc-shaped portion is provided with first wire pressing ribs along the circumference of the disc body at intervals, and a first wire winding space for winding the first wire group is formed between the arc-shaped portion and the first wire pressing ribs; the bottom wall is provided with second wire pressing ribs along the circumference of the disc body at intervals, and a planar wire winding area is formed, and a second wire winding space for winding the second wire group is formed between the second wire pressing ribs and the planar wire winding area; and the number of the first wire pressing ribs is not less than the number of the second wire pressing ribs.

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