Low-voltage fan with insulation structure, mold and air fryer

Abstract

The application discloses a low-voltage fan with an insulation structure, a mold and an air fryer, and is applied to the air fryer. The low-voltage fan comprises a stator core, a plurality of winding columns are arranged in a circumferential interval between a central hole and an outer circumferential surface surrounding the central hole, an insulation piece is integrally formed with the stator core by injection molding, the insulation piece is coated on all surfaces of the stator core except the inner wall surface of the central hole and the radial outer side surface of the outer circumferential surface with a preset thickness, the insulation piece is formed with an insulated winding slot on the outer circumferential surface of each winding column, and a continuous insulation end surface is formed on the end surface of the stator core, a winding is arranged in the winding slot of the insulation piece, and the preset thickness is configured to withstand an at least 1250V power frequency withstand voltage test between the outer circumferential surface and the winding. The low-voltage fan and the air fryer have better pressure resistance.

Description

Technical Field

[0001] This application relates to the field of kitchen appliance technology, and more specifically, to a low-pressure fan with an insulating structure, a mold, and an air fryer. Background Technology

[0002] An air fryer, a kitchen appliance that uses high-speed air circulation technology for cooking, works by generating heat through a heating element and using a fan to drive airflow, which then forms hot air to evenly heat the food inside the cooking cavity. In this system, the fan and its motor drive system directly affect hot air efficiency, temperature uniformity, energy consumption, and noise levels, making them key components influencing product performance and user experience.

[0003] Currently, there are two main technical solutions for fan-driven air fryers on the market, each with its own significant limitations: Shaded-pole motor fan solution: This solution is widely used due to its simple structure and low cost. However, its inherent drawback is that it usually lacks speed regulation, and the fan can only operate at a fixed speed. This makes it difficult to optimize constant energy consumption, cannot reduce operating noise, and the system cannot dynamically adjust the airflow according to the internal temperature or cooking stage, thus hindering the improvement of cooking results and the development of intelligent features.

[0004] Isolated Brushless Motor Fan Solution: To overcome the aforementioned speed control bottleneck, some products employ brushless DC motors to achieve intelligent speed regulation and efficient control. However, to ensure user safety and prevent high-voltage grid voltage from entering the low-voltage control circuit through the motor windings, this solution requires the drive circuit to include high-voltage electrical isolation components such as isolation transformers and optocouplers. These isolation components not only significantly increase circuit complexity and material costs (typically increasing the overall cost by tens of yuan), but also occupy valuable circuit board space. In the cost-sensitive home appliance industry, this additional cost severely hinders the widespread application of high-performance variable-speed fans.

[0005] The predicament of the above-mentioned technical approach reveals a deep-seated industry contradiction: when using brushless motors to achieve intelligent speed control of fans, the insufficient safety margin of their own insulation system forces them to rely on external circuits for high-voltage isolation, resulting in a systemic increase in costs.

[0006] Therefore, there is an urgent need in this field for a breakthrough technical solution to fundamentally resolve the contradiction between "intelligent speed control" and "cost control," and to promote the widespread adoption of high-performance, high-safety, and low-cost air fryers. Utility Model Content

[0007] In view of this, this application provides a low-pressure fan, mold, and air fryer with an insulating structure, which enables the low-pressure brushless fan to withstand the high voltage impact of the power grid. While achieving intelligent stepless speed regulation of the fan in the air fryer, it eliminates the need for expensive external isolation circuits, ultimately achieving a balance between high performance and low cost in air fryer applications.

[0008] In a first aspect, this application provides a low-pressure fan with an insulating structure, including a stator assembly and a rotor assembly, for use in an air fryer, wherein the stator assembly includes: The stator core includes a central hole and an outer peripheral surface surrounding the central hole, with a plurality of winding posts circumferentially spaced between the central hole and the outer peripheral surface. An insulating component is injection molded integrally with the stator core. The insulating component covers all surfaces of the stator core except for the inner wall surface of the central hole and the radially outer surface of the outer peripheral surface with a predetermined thickness. The insulating component forms an insulating winding groove on the outer periphery of each winding post and forms a continuous insulating end face on the end faces at both ends of the stator core. The winding is wound within the winding slot of the insulating component; The preset thickness is configured such that the outer peripheral surface and the winding can withstand an insulation withstand voltage test of 1250V AC voltage for 1 minute.

[0009] By adopting the above technical solution, the insulation component and stator core are integrated into a single structure through injection molding, achieving complete coverage of the core except for the inner wall of the central hole and the outer radial surface. This fundamentally eliminates the assembly gap between the traditional separate insulation component and the core, ensuring the continuity and integrity of the insulation medium. In particular, the continuous design of the insulation end face eliminates the risk of creepage along the end face of the core laminations. By configuring the withstand voltage rating of the insulation layer to at least 1250V, the motor stator assembly itself has the ability to resist the impact of abnormal high voltage (such as surge) from the power grid, thus providing crucial internal insulation protection to eliminate the need for an external high voltage isolation circuit, achieving a revolution in the insulation structure of the motor body.

[0010] In some implementations, the preset thickness of the insulation at the location covering the winding post is not less than 0.8 mm.

[0011] By adopting the above technical solution, an insulation thickness of no less than 0.8 mm is ensured at the critical location of the winding post, where the electric field is concentrated and the winding is in direct contact. This facilitates injection molding and provides a reliable and quantifiable structural basis for high withstand voltage ratings of 1250V and above. This specific thickness requirement transforms high insulation performance from a design specification into a manufacturable and verifiable physical characteristic, significantly improving the product's safety margin and reliability consistency.

[0012] In some embodiments, at least one end face of the insulating member has a plurality of spaced-apart limiting ribs extending axially, the limiting ribs being disposed between the winding and the outer peripheral surface.

[0013] By adopting the above technical solution, the limiting ribs form a physical barrier between the winding end and the outer peripheral surface, effectively restraining the radial displacement or loosening of the winding that may occur during the winding process or long-term operation vibration, preventing it from contacting the outer peripheral surface of the stator core or shortening the insulation distance. This feature, in conjunction with the integrally injection-molded insulation matrix, enhances the mechanical reliability of winding fixation while providing high-voltage main insulation, further ensuring the long-term stability of the insulation system.

[0014] In some embodiments, the end face of the insulating element has an axially extending annular rib that surrounds the outer periphery of the central hole and between the winding.

[0015] By employing the above technical solution, the annular ribs construct an axially extending insulation barrier between the winding end and the area near the stator core center hole. This significantly increases the surface creepage distance along this critical path, greatly extending the potential leakage current path and effectively suppressing the risk of surface flashover in high humidity or polluted environments. This feature, combined with the aforementioned overall encapsulation and thickened insulation, constitutes a multi-dimensional insulation reinforcement system.

[0016] In some implementations, the inner wall of the central hole is provided with a recessed anti-rotation groove, which corresponds to the winding post.

[0017] By adopting the above technical solution, the concave anti-rotation groove and the corresponding protrusion or key of the motor shaft can effectively prevent the stator assembly from rotating circumferentially during operation and ensure its installation stability.

[0018] In some implementations, the width of the anti-rotation groove is smaller than the width of the winding post.

[0019] By adopting the above technical solution, the width of the anti-rotation slot is designed to be smaller than the width of the winding post. This ensures sufficient material strength to support the slotted core, preventing excessive weakening of the core yoke structure due to slotting and thus affecting the overall mechanical strength and magnetic circuit performance of the stator assembly. This demonstrates that while achieving the anti-rotation function, the integrity of the core structure of the stator assembly is also taken into account.

[0020] In some implementations, the radial dimension of the anti-rotation groove is smaller than the radius of the rib.

[0021] By adopting the above technical solution, the radial dimension (depth) of the anti-rotation groove is limited to a range smaller than the radius of the annular rib, ensuring that the rib used to increase the creepage distance has sufficient root thickness and mechanical strength, preventing easy damage due to excessively thin ribs. At the same time, this quantitative relationship also optimizes the material distribution of the insulating component on the end face, taking into account both insulation performance and structural reliability.

[0022] Secondly, this application provides a mold for injection molding a low-pressure fan with an insulating structure as described in the first aspect. The mold has a cavity, the cavity including a sidewall for engaging with the outer peripheral surface, and a positioning post at the center of the cavity for engaging with the central hole.

[0023] By adopting the above technical solution, the specialized mold, through its cavity sidewalls and central positioning post, can accurately position and seal the outer peripheral surface and central hole of the stator core during the injection molding process, ensuring that the molten insulating material can uniformly fill and cover all areas of the stator core except for the two sealing surfaces mentioned above. This is a key process guarantee for achieving integral molding of the insulating component and the core with uniform and controllable thickness, enabling the high-performance insulating structure described in the first aspect to be mass-produced with high consistency and high efficiency.

[0024] Thirdly, this application provides an air fryer including the low-pressure fan with an insulating structure as described in the first aspect.

[0025] By adopting the above technical solution, a low-voltage fan with a high insulation rating is applied to the air fryer, directly improving the overall electrical safety of the machine. The high voltage resistance of the fan motor itself reduces the safety risks caused by motor insulation failure, making the air fryer's hot air drive system more reliable.

[0026] In some implementations, the power circuit of the air fryer is electrically connected to the winding of the low-pressure fan, and no isolation transformer and optocoupler are provided on the power transmission path of this electrical connection.

[0027] By adopting the above technical solution, and using a fan motor that is self-insulated and can withstand high-voltage surges from the power grid, the air fryer's drive circuit no longer needs to be equipped with additional high-voltage isolation components such as isolation transformers or optocouplers. This not only directly and significantly reduces the material cost of the electronic components and the space occupied on the circuit board, but also simplifies the circuit design, improves the system's power density and reliability, and fundamentally solves the industry pain point of high costs caused by the need for isolation in traditional brushless motor solutions.

[0028] In summary, this application has at least one of the following beneficial technical effects: 1. A revolutionary improvement in motor insulation and optimization of cost system: Through the innovative "integrated injection molding complete encapsulation" insulation structure, the low-voltage fan stator assembly itself achieves an insulation level that can directly withstand high-voltage surges from the power grid (such as 1250V). This fundamental improvement allows air fryers using this fan to safely eliminate the isolation transformer or optocoupler required in traditional brushless motor drives. While achieving the high-performance goal of intelligent stepless speed regulation of the fan, it breaks through the cost bottleneck and achieves a balance between high performance and low cost.

[0029] 2. A multi-layered collaborative insulation safety system has been constructed: The technical solution is not an improvement of a single feature, but rather a comprehensive, highly redundant insulation safety system that is built from body insulation to surface insulation, and from static withstand voltage to long-term reliability. This is achieved through the collaborative design and combination of multiple structural features such as "overall coverage to ensure integrity", "thickening of key parts to ensure strength", "addition of ribs to extend creepage distance", and "setting of limiting ribs to ensure winding stability". This significantly improves the long-term safety and lifespan of the product in harsh kitchen environments.

[0030] 3. Balancing High-Performance Insulation with High-Reliability Structure: While pursuing high insulation performance, the solution fully considers the product's manufacturability and structural reliability. For example, the size design of the anti-rotation groove balances positioning function and core strength; the relationship between the radius of the raised rib and the depth of the anti-rotation groove optimizes the insulation component structure; and the design of the dedicated mold ensures the realization of the one-piece molding process. These features work together to ensure that this innovative structure can be stably and efficiently transformed into actual products.

[0031] 4. Provides a quantifiable and verifiable basis for reliability: By quantifying insulation performance into "at least 1250V withstand voltage test" and "thickness requirement of not less than 0.8 mm," the superiority of this insulation structure has a clear and objective verification standard. This not only provides a clear basis for product design and quality control, but also makes the advancement and reliability of this technical solution easier to evaluate and confirm, enhancing the practical value and market persuasiveness of the patented technology. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the external structure of an embodiment of a low-voltage fan with an insulating structure according to this application; Figure 2 This is a schematic diagram of the assembly structure of the low-pressure fan rotor assembly and stator assembly of this application; Figure 3 This is a schematic diagram of the structure of the stator core and the insulating components. Figure 4 yes Figure 3 A cross-sectional view of the cross section; Figure 5 yes Figure 3 Sectional view of the longitudinal section AA; Figure 6 yes Figure 3 Longitudinal section view of BB; Figure 7 This is a schematic diagram of the stator core structure; Figure 8 This is a schematic diagram of the insulating component; Figure 9 This is a schematic diagram of the mold structure of this application; Figure 10 This is a schematic diagram of the structure of the mold and the stator core in operation; Figure 11 This is a schematic diagram showing the mold opening state after injection molding is completed; Figure 12 This is a schematic diagram of the air fryer used in this application.

[0033] Explanation of reference numerals in the attached drawings: 100, low-pressure fan; 1, wiring; 2, mounting bracket; 3, stator assembly; 31, insulating component; 311, winding groove; 312, raised rib; 313, limiting rib; 32, winding; 33, iron core; 331, center hole; 332, anti-rotation groove; 333, outer peripheral surface; 334, winding post; 4, moving part assembly; 200, mold; 5, mold core; 51, positioning post; 52, cavity; 521, side wall; 300, air fryer; 6, main body; 61, cooking cavity. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the utility model will be further described in detail below with reference to the accompanying drawings. The components of the embodiments of this utility model described and shown in the accompanying drawings can be arranged and designed in various different configurations. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0035] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0037] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application.

[0038] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments can be combined with each other.

[0039] Example 1: Low-voltage fan with insulation structure This embodiment provides a low-pressure fan with a high insulation rating for use in air fryers. The core innovation of this fan lies in the unique insulation structure of its stator assembly, which is achieved through a one-piece injection molding process. This allows the motor body to directly withstand high-voltage impacts, thereby saving the external high-voltage isolation circuit required in traditional solutions for the entire system.

[0040] refer to Figures 1 to 8 The low-pressure fan 100 mainly includes a mounting frame 2, connecting wires 1, a stator assembly 3, and a rotor assembly 3. The stator assembly 3, as the fixed part, is the key carrier of the insulation structure. The stator assembly 3 includes a stator core 33, an insulator 31, and windings 32. The stator core 33 is a stator core 33 made of multiple stacked silicon steel sheets. The stator core 33 has a central hole 331 and an outer peripheral surface 333 surrounding the central hole. Between the central hole 331 and the outer peripheral surface 333, multiple winding posts 334 extend circumferentially and at uniform intervals. The inner wall of the central hole 331 of the stator core 33 usually also has a recessed anti-rotation groove 332. The position of the anti-rotation groove 332 preferably corresponds to the extension direction of the winding posts 334, and its width is designed to be smaller than the width of the winding posts 334 to ensure that the core yoke has sufficient structural strength.

[0041] Please see Figures 3 to 8 The core of this invention lies in the integral molding of an insulating component 31 onto the stator core 33 using an injection molding process. This insulating component 31 is not a simple kit or skeleton, but rather, with a predetermined uniform thickness, it tightly covers all surfaces of the stator core 33 except for the inner wall surface of the central hole 331 and the radially outer surface of the outer peripheral surface 333. This means that the two axial end faces of the stator core 33, all sides of each winding post 334, and some gaps between the core laminations are completely covered by insulating material, thus physically forming a continuous and uninterrupted insulating barrier.

[0042] Specifically, the insulating component 31 precisely forms an annular winding groove 311 on the outer periphery of each winding post 334 to accommodate the winding 32. On the two axial end faces of the stator core 33, the insulating component 31 forms a large-area continuous insulating end face. More importantly, the thickness of the insulating component 31 at the location covering the winding post 334, i.e., the thickness of the groove wall of the winding groove 311, is set to be no less than 0.8 mm; in this embodiment, it is 1 mm. This specific dimension is not arbitrarily chosen but determined through theoretical calculations and experimental verification to reliably ensure that the outer periphery 333 of the stator core 33 and the winding 32 wound within the winding groove 311 (GB4706 series standard) can withstand a power frequency withstand voltage test of at least 1250V for 1 minute without breakdown or flashover, thus meeting the insulation requirements for directly resisting potential high-voltage surges in the power grid.

[0043] Please see Figure 3 and Figure 8 To further enhance the reliability and mechanical stability of the insulation system, the structure of the insulating component 31 has been optimized. Multiple spaced retaining ribs 313 extend axially from at least one of its insulating end faces. These retaining ribs 313 are located in the area between the end coil of the winding 32 and the outer peripheral surface 333, acting like a guardrail to effectively prevent radial displacement or loosening of the winding 32 during operational vibrations, ensuring that the winding end always maintains a safe insulation distance from the core. Simultaneously, an annular raised rib 312 is integrally formed on the insulating end face, surrounding the central hole 331 and the end of the winding 32. The main function of this raised rib 312 is to significantly increase the creepage distance on the surface of this area. Even in high humidity environments where condensation may form on the surface, the raised rib 312 can effectively block potential leakage paths. In some preferred designs, the radial depth (dimension) of the anti-rotation groove 332 inside the central hole 331 is limited to a radius smaller than that of the annular raised rib 312. This design ensures that the raised rib 312 has sufficient root strength and insulation thickness.

[0044] Please see Figures 2 to 4 The winding 32 is wound within the winding groove 311 of the insulator 31, thus completing the manufacturing of the stator assembly 3. The mover assembly 3 (typically including a permanent magnet and a shaft) is rotatably mounted within the central hole 331 of the stator assembly 3 via a structure such as bearings, interacting with the magnetic field of the stator assembly 3 to form a complete motor. The fan impeller is mounted on the shaft of the mover assembly 3. The entire motor can be mounted in the corresponding position on the air fryer via the mounting bracket 2 and connected to an external drive circuit via the connecting wire 1.

[0045] Example 2: Mold To achieve high-quality integrated molding of the above-mentioned insulating component 31 and stator core 33, this embodiment also provides a dedicated mold 200.

[0046] like Figures 9 to 11 As shown. The mold 200 includes a front mold and a rear mold arranged opposite each other. Both the front mold and the rear mold are provided with mold cores 5, and the mold cores 5 define cavities 52 corresponding to the shape of the final product. After the stator core 331 is placed into the cavity 52 of one of the mold cores 5 and the mold is closed, the mold cores of the front mold and the rear mold form injection spaces for plastic flow. The cavity 52 includes a side wall 521 for radial positioning and sealing, which mates with the outer peripheral surface 333 of the stator core 33. At the center of the cavity 52, a positioning post 51 is provided, which can be inserted into the center hole 331 of the stator core 33. During injection molding, the stator core 33 is placed into the cavity 52 of the mold 200, with its outer peripheral surface 333 in close contact with the side wall 521, and the center hole 331 fitted onto the positioning post 51. These two contact surfaces are precisely sealed, so that the molten insulating material can only flow into and fill all other surfaces and gaps of the stator core 33, thereby precisely forming a coating layer of a preset thickness. After mold opening, an integrated stator assembly with perfect combination of insulation and iron core can be obtained.

[0047] Example 3: Air Fryer When the low-pressure fan 100 described above is applied to the air fryer 300, such as Figure 12 As shown, the air fryer 300 includes a main body 6, which has a cooking cavity. A fan 100 is positioned above the cooking cavity 61 within the main body 6 to drive the circulation of hot air within the cooking cavity 61. (See reference...) Figure 2 and Figure 3 Because the stator assembly 3 of the fan has an extremely high insulation level (withstanding voltage above 1250V), its winding 32 already has sufficient safety isolation capability between itself and the high voltage of the power grid. Therefore, in the power transmission path between the power circuit of the air fryer and the fan winding 32, there is no longer a need to install traditional isolation transformers or optocoupler isolators or other high-voltage isolation components. The drive circuit can adopt a simpler and more direct non-isolated topology (such as the common Buck circuit or a dedicated non-isolated motor drive chip), which directly leads to a significant reduction in the material cost of electronic components, a simplification of circuit board layout, and an improvement in overall reliability.

[0048] In summary, this embodiment, through its "integrated injection molding, complete encapsulation, and thickened key components" insulation structure design, combined with auxiliary structures such as limiting ribs and protruding ribs, creatively elevates the insulation capability of the low-voltage fan to a new level. This fundamental improvement allows end products using this fan (such as air fryers) to eliminate the need for expensive external isolation circuits while ensuring electrical safety, thus perfectly resolving the long-standing industry contradiction between "high-performance intelligent speed regulation" and "low-cost control."

[0049] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments; the embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes, modifications, substitutions, and variations can be made to this utility model without departing from its spirit and scope, and all such changes, modifications, substitutions, and variations fall within the scope of the claimed utility model.

Claims

1. A low-voltage fan with an insulating structure, comprising a stator assembly and a rotor assembly, characterized in that, The stator assembly, used in air fryers, includes: The stator core includes a central hole and an outer peripheral surface surrounding the central hole, with a plurality of winding posts circumferentially spaced between the central hole and the outer peripheral surface. An insulating component is injection molded integrally with the stator core. The insulating component covers all surfaces of the stator core except for the inner wall surface of the central hole and the radially outer surface of the outer peripheral surface with a predetermined thickness. The insulating component forms an insulating winding groove on the outer periphery of each winding post and forms a continuous insulating end face on the end faces at both ends of the stator core. The winding is wound within the winding slot of the insulating component; The preset thickness is configured such that the outer peripheral surface and the winding can withstand an insulation withstand voltage test of 1250V AC voltage for 1 minute.

2. The low-pressure fan according to claim 1, characterized in that, The preset thickness of the insulating component covering the winding post is not less than 0.8 mm.

3. The low-pressure fan according to claim 1, characterized in that, At least one end face of the insulating member has a plurality of spaced-apart limiting ribs extending axially, the limiting ribs being disposed between the winding and the outer peripheral surface.

4. The low-pressure fan according to claim 1, characterized in that, The end face of the insulating element has an axially extending annular rib, which surrounds the outer periphery of the central hole and between the windings.

5. The low-pressure fan according to claim 4, characterized in that, The inner wall of the central hole is provided with a concave anti-rotation groove, which corresponds to the winding post.

6. The low-pressure fan according to claim 5, characterized in that, The width of the anti-rotation groove is smaller than the width of the winding post.

7. The low-pressure fan according to claim 5, characterized in that, The radial dimension of the anti-rotation groove is smaller than the radius of the rib.

8. A mold, characterized in that, For injection molding of a low-pressure fan with an insulating structure according to any one of claims 1 to 7, the mold has a cavity, the cavity including a sidewall for engaging with the outer peripheral surface, and a positioning post at the center of the cavity for engaging with the center hole.

9. An air fryer, characterized in that, Including a low-pressure fan with an insulating structure as described in any one of claims 1 to 7.

10. The air fryer according to claim 9, characterized in that, The power circuit of the air fryer is electrically connected to the winding of the low-pressure fan, and no isolation transformer or optocoupler is installed on the power transmission path of this electrical connection.

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