Plastic package magnetic device and method of manufacturing the same

Abstract

The application relates to the technical field of magnetic device, and discloses a plastic-sealed magnetic device and a preparation method thereof. The preparation method of the plastic-sealed magnetic device comprises the following steps: pressing and combining partial laminated coils to form a first winding, the outer surface of the first winding is provided with a plurality of first pin positioning areas; using injection molding material to perform one-time injection molding on the first winding to form a first sealing glue body, the first sealing glue body wraps or partially wraps the area of the first winding except the first pin positioning areas; pressing and combining partial laminated coils to form a second winding, the outer surface of the second winding is provided with a plurality of second pin positioning areas; using injection molding material to perform one-time injection molding on the second winding to form a second sealing glue body, the second sealing glue body wraps or partially wraps the first sealing glue body, and wraps or partially wraps the area of the second winding except the second pin positioning areas; and assembling the first winding and the second winding in a containing cavity of a magnetic core main body. The application improves the reliability of the device.

Description

Technical Field

[0001] This application relates to the field of magnetic device technology, specifically to a plastic-encapsulated magnetic device and its fabrication method. Background Technology

[0002] Magnetic devices are key electronic components that utilize the principle of electromagnetic induction to achieve energy conversion, transmission, and storage. They are widely used in power management, signal processing, and electromagnetic compatibility, including transformers and inductors. In terms of specific structure, they can include magnetic cores, coils, frames, terminals, and packages. With the development of the electronics industry, the application voltage of magnetic devices is getting higher and higher. Taking transformer products as an example, the insulation of the products mainly relies on wire insulation layers and tape insulation, resulting in insufficient insulation capacity. Under high voltage and high frequency environments, the temperature of the products rises, and partial discharge becomes serious, affecting the reliability of the devices. This situation needs to be changed. Summary of the Invention

[0003] In view of this, this application provides a plastic-encapsulated magnetic device and its fabrication method to solve the aforementioned technical problems.

[0004] To achieve the above objectives, based on the first aspect, the technical solution adopted is as follows:

[0005] A method for fabricating a plastic-encapsulated magnetic device, comprising:

[0006] A plurality of coils are provided, and the coils are stacked in a pressed part to form a first winding. The outer surface of the first winding has a plurality of first pin positioning areas.

[0007] The first winding is injection molded with injection molding material to form a first sealing compound. The first sealing compound covers or partially covers the area of ​​the first winding excluding the first ejector pin positioning area.

[0008] The coils partially stacked on the first encapsulant form a second winding, and the outer surface of the second winding has a plurality of second pin positioning areas;

[0009] The second winding is injection molded once using the injection molding material to form a second sealing material. The second sealing material wraps or partially wraps the first sealing material, and wraps or partially wraps the area of ​​the second winding excluding the second ejector pin positioning area.

[0010] The first winding and the second winding are assembled in the accommodating cavity of the magnetic core body.

[0011] This application further includes, before assembling the first winding and the second winding in the receiving cavity of the magnetic core body, the following:

[0012] The second sealant is formed by at least one injection molding process using the injection molding material, wherein the sealant encapsulates the second sealant, the second winding, the first sealant, and the first winding.

[0013] This application further includes, before assembling the first winding and the second winding in the receiving cavity of the magnetic core body, the following:

[0014] The coils that are partially laminated on the second sealant form an extended winding, and the outer surface of the laminated extended winding has a plurality of extended pin positioning areas.

[0015] The extended winding is injection molded once using the injection molding material to form an extended sealing body. The extended sealing body wraps or partially wraps the second sealing body, and wraps or partially wraps the area of ​​the extended winding excluding the extended ejector pin positioning area.

[0016] This application is further configured such that: the accommodating cavity of the magnetic core body is provided with a magnetic post, the first winding and the second winding are sleeved and connected to the magnetic post, the first winding has a first lead end, the second winding has a second lead end, and the first lead end and the second lead end extend toward each other outside the magnetic core body.

[0017] This application is further configured such that: a plurality of first ejector pin positioning areas are uniformly arranged on the outer surface of the first winding, and a plurality of second ejector pin positioning areas are uniformly arranged on the outer surface of the second winding, wherein the vertical projection areas of the first ejector pin positioning areas and the second ejector pin positioning areas relative to the magnetic core body are not at the same position.

[0018] This application is further configured such that: there is a compression gap between adjacent coils in the first winding and the second winding, and the compression gap is ≤10% of the thickness of the coil.

[0019] This application further specifies that: the area of ​​the first sealant covering the first winding is ≥10% of the surface area of ​​the first winding, and the area of ​​the second sealant covering the second winding is ≥10% of the surface area of ​​the second winding.

[0020] This application further specifies that the thickness of the first sealant and / or the second sealant is ≥0.3mm.

[0021] This application further specifies that: the injection molding material includes at least one of polyethylene terephthalate, acrylonitrile-butadiene-styrene copolymer, polyamide or polycarbonate, and the injection molding materials of the first sealant and the second sealant are different.

[0022] According to the second aspect, the technical solution adopted is as follows:

[0023] A plastic-encapsulated magnetic device, prepared by the plastic-encapsulated magnetic device fabrication method described in any of the foregoing embodiments, comprises:

[0024] A magnetic core body, wherein a receiving cavity is formed inside the magnetic core body;

[0025] Several coils, some of which are stacked and pressed together to form a first winding, the outer surface of the first winding having multiple first pin positioning areas;

[0026] The first sealing material covers or partially covers the area of ​​the first winding excluding the first ejector pin positioning area. The coils stacked on the first sealing material constitute the second winding. The outer surface of the second winding has multiple second ejector pin positioning areas.

[0027] The second sealing material wraps or partially wraps the first sealing material, and wraps or partially wraps the area of ​​the second winding excluding the second ejector pin positioning area;

[0028] The first winding and the second winding are connected in the accommodating cavity.

[0029] In summary, compared with the prior art, this application discloses a plastic-encapsulated magnetic device and its manufacturing method. The first winding is formed by pressing partially stacked coils together and has multiple first pin positioning areas. After the first winding is injection molded with injection molding material to form a first sealing compound, the first sealing compound wraps or partially wraps the area of ​​the first winding excluding the first pin positioning areas. The partially stacked coils are pressed onto the first sealing compound to form a second winding. The outer surface of the second winding has multiple second pin positioning areas. After the second winding is injection molded with injection molding material to form a second sealing compound, the second sealing compound wraps or partially wraps the first sealing compound and the area of ​​the second winding excluding the second pin positioning areas. The first winding and the second winding are assembled in the accommodating cavity of the magnetic core body. That is, through the above arrangement, the first winding and the second winding of the plastic-encapsulated magnetic device are wrapped by the first sealing compound and the second sealing compound in a single injection molding process, that is, the winding is integrated and insulated, which improves the mechanical stability and insulation capability of the magnetic device. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a process flow diagram of the fabrication method of the plastic-encapsulated magnetic device in this embodiment;

[0032] Figure 2 This is a schematic diagram of the structure of the first type of encapsulated magnetic device in this embodiment;

[0033] Figure 3 This is a schematic diagram of the structure of the second type of encapsulated magnetic device in this embodiment;

[0034] Figure 4 This is a schematic diagram of the structure of the third type of encapsulated magnetic device in this embodiment;

[0035] Figure 5 This is a schematic diagram of the structure of the fourth type of encapsulated magnetic device in this embodiment;

[0036] Figure 6 This is a schematic diagram of the structure of the fifth type of encapsulated magnetic device in this embodiment;

[0037] Figure 7 This is a schematic diagram of the structure of the sixth type of encapsulated magnetic device in this embodiment;

[0038] Figure 8 This is a schematic diagram of the structure of the seventh type of encapsulated magnetic device in this embodiment. Detailed Implementation

[0039] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0040] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, components, features, and elements with the same names in different embodiments of this application may have the same meaning or different meanings, the specific meaning of which must be determined by its interpretation in that specific embodiment or further in conjunction with the context of that specific embodiment.

[0041] It should be further understood that the terms "comprising" or "including" indicate the presence of the stated features, steps, operations, elements, components, items, types, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, types, and / or groups. The terms "or," "and / or," and "comprising at least one of the following," as used in this application, can be interpreted as inclusive, or mean any one or any combination thereof. For example, "comprising at least one of the following: A, B, C" means "any one of the following: A; B; C; A and B; A and C; B and C; A and B and C," and similarly, "A, B, or C" or "A, B, and / or C" means "any one of the following: A; B; C; A and B; A and C; B and C; A and B and C." Exceptions to this definition only occur when the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0042] It should be understood that although the terms first, second, third, etc., may be used in this document to describe various types of information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this document, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the singular forms “a,” “an,” and “the” used in this document are intended to also include the plural forms, unless the context indicates otherwise.

[0043] It should be understood that the terms "top", "bottom", "upper", "lower", "vertical", "horizontal", 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 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 on this application.

[0044] For ease of description, the following embodiments are all illustrated using an orthogonal space formed by a horizontal plane and a vertical direction as an example. This premise should not be construed as a limitation of this application.

[0045] Please refer to Figure 1 , Figure 1 This is a process flow diagram of the fabrication method of the plastic-encapsulated magnetic device according to this embodiment. The fabrication method of the plastic-encapsulated magnetic device of this application includes:

[0046] S101 provides several coils 1, and the coils 1 stacked in the pressing part form a first winding 2. The outer surface of the first winding 2 has multiple first pin positioning areas 3.

[0047] In this step, refer to Figure 2 and Figure 3The first winding 2 is formed by pressing the partially stacked coils 1 together. Specifically, the mold ejector pins can act on the partially stacked coils 1 to press the gaps between the coils 1 together, compress the space of the coils 1, and obtain a smaller volume first winding 2. The outer surface of the first winding 2 has multiple first ejector pin positioning areas 3. These first ejector pin positioning areas 3 can be regarded as the area where the mold ejector pins act on the coils 1, or they can be used as the alignment point for the subsequent injection molding, thereby ensuring that the first winding 2 is pressed evenly.

[0048] In one embodiment, the first pin positioning area 3 of the first winding 2 can be marked with a color code.

[0049] S102, the first winding 2 is injection molded with injection molding material to form the first sealing compound 4. The first sealing compound 4 wraps or partially wraps the area of ​​the first winding 2 excluding the first ejector pin positioning area 3.

[0050] In this step, continue to combine Figure 3 The first sealing compound 4, acting as an insulator, is wrapped or partially wrapped around the first winding 2 by injection molding material in a single injection molding process, thereby fixing the coil 1 of the first winding 2 and forming a good insulation structure on the first winding 2.

[0051] It is understandable that the first ejector pin positioning area 3, as the action point of the aforementioned mold ejector pin, is not wrapped by the first sealing colloid 4. At the same time, the wrapping and sealing effect of the first winding 2 can be observed through the first ejector pin positioning area 3, ensuring the reliability of the winding structure.

[0052] S103, the coil 1 partially stacked on the first sealing adhesive 4 forms the second winding 5, and the outer surface of the second winding 5 has a plurality of second pin positioning areas 6.

[0053] In this step, refer to Figure 4 and Figure 5 The second winding 5 can be formed by pressing and bonding a portion of the coil 1 on the first sealing body 4, thereby pressing and bonding the gap between the coils 1 on the first sealing body 4 to obtain a second winding 5 with a smaller volume. The outer surface of the second winding 5 has a plurality of second ejector pin positioning areas 6. These second ejector pin positioning areas 6 can be regarded as the area where the mold ejector pin acts on the coil 1 on the first sealing body 4, or the second ejector pin positioning areas 6 can be used as the alignment point for the subsequent injection molding.

[0054] The second winding 5 of this application is formed on the first sealing compound 4. The first sealing compound 4 can effectively isolate the first winding 2 and the second winding 5, ensuring the insulation and energy resistance between them and avoiding partial discharge during normal operation of the device.

[0055] In one embodiment, a portion of the coil 1 can be provided on one side of the first sealing compound 4, or a portion of the coil 1 can be provided on both sides of the first sealing compound 4. That is, the second winding 5 can be arranged sequentially with the first winding 2, or the first winding 2 can be symmetrically clamped. This can be specifically set based on environmental requirements and product performance requirements.

[0056] S104, the second winding 5 is injection molded once using injection molding material to form a second sealing compound 7, the second sealing compound 7 wraps or partially wraps the first sealing compound 4, and wraps or partially wraps the area of ​​the second winding 5 excluding the second ejector pin positioning area 6.

[0057] In this step, continue to combine Figure 5 The second sealing compound 7 acts as an insulator, and wraps or partially wraps the first sealing compound 4 in a single injection molding process, as well as wraps or partially wraps the area of ​​the second winding 5 excluding the second ejector pin positioning area 6, thereby fixing the coil 1 of the second winding 5 and forming a good insulating isolation structure on the second winding 5.

[0058] Understandably, the second ejector pin positioning area 6 serves as the point of action for the aforementioned mold ejector pins and is not encased by the second sealing compound 7. At the same time, the encapsulation and sealing effect of the second winding 5 can be observed through the second ejector pin positioning area 6, ensuring the reliability of the winding structure.

[0059] Therefore, the second sealing compound 7 is applied to the second winding 5 and the first sealing compound 4 through a one-time injection molding process, thereby ensuring the insulation and energy resistance between the first winding 2 and the second winding 5, as well as between the second winding 5 and the outside world, avoiding partial discharge during normal operation of the device. This improves the insulation capability and structural strength of the magnetic device, and the first winding 2 and the second winding 5 formed by pressing also meet the miniaturization requirements of the magnetic device.

[0060] In one embodiment, combined Figure 5 and Figure 6 After the second sealing colloid 7 is formed, the second sealing colloid 7 can be injection molded at least once using injection molding material to form a sealing colloid 10. The sealing colloid 10 encapsulates the second sealing colloid 7, the second winding 5, the first sealing colloid 4, and the first winding 2, thereby further improving the insulation withstand voltage and structural strength of the magnetic device.

[0061] S105, the first winding 2 and the second winding 5 are assembled in the accommodating cavity 9 of the magnetic core body 8.

[0062] In this step, refer to Figure 7 and Figure 8The first winding 2 and the second winding 5 are assembled in the accommodating cavity 9 of the magnetic core body 8 to complete the combination of the windings of the device with the magnetic core. The magnetic core body 8 matches the first winding 2 and the second winding 5 through the accommodating cavity 9 opened inside, thereby ensuring structural stability.

[0063] The magnetic core body 8 has a cavity 9 with a magnetic post 13. The first winding 2 and the second winding 5 are sleeved and connected to the magnetic post 13. The first winding 2 has a first lead end 14 and the second winding 5 has a second lead end 15. The first lead end 14 and the second lead end 15 extend towards each other outside the magnetic core body 8. That is, the first lead end 14 and the second lead end 15 can be used as connection terminals of magnetic devices to be electrically connected to the outside. At the same time, the magnetic post 13 can also help fix the first winding 2 and the second winding 5. Based on the design of the first sealant 4 and the second sealant 7, the second sealant 7 can be attached to the magnetic post 13 or have a gap with the magnetic post 13.

[0064] In one embodiment, continue to combine Figure 5 and Figure 6 Before assembling the first winding 2 and the second winding 5 into the receiving cavity 9 of the magnetic core body 8, a partially stacked coil 1 can be pressed onto the second sealing body 7 to form an extended winding 11. The outer surface of the stacked extended winding 11 has multiple extended ejector pin positioning areas. Similarly, the coil 1 stacked on the second sealing body 7 can be acted on by the mold ejector pins. The extended winding 11 can be injection molded once using injection molding material to form an extended sealing body 12. The extended sealing body 12 wraps or partially wraps the second sealing body 7 and wraps or partially wraps the area of ​​the extended winding 11 excluding the extended ejector pin positioning areas.

[0065] That is, the magnetic device of this application is not limited to the assembly form of the first winding 2 and the second winding 5. Based on environmental and product performance requirements, the device function can be enriched by extending the winding 11, and the insulation effect between the extended winding 11 and the second winding 5, as well as between the extended winding 11 and the outside world, can be ensured by extending the encapsulant 12, thereby improving the insulation capability and structural strength of the magnetic device.

[0066] In other words, based on the aforementioned process of the first sealing compound 4 and the second sealing compound 7, this application can continue to stack the third winding and the third sealing compound, the fourth winding and the fourth sealing compound, and the fifth winding and the fifth sealing compound, etc., which will not be elaborated here.

[0067] It should be noted that in this application, multiple first pin positioning areas 3 are evenly arranged on the outer surface of the first winding 2, and multiple second pin positioning areas 6 are evenly arranged on the outer surface of the second winding 5. The vertical projection areas of the first pin positioning areas 3 and the second pin positioning areas 6 relative to the magnetic core body 8 are not at the same position, that is, the vertical projection areas of the first pin positioning areas 3 and the second pin positioning areas 6 relative to the magnetic core body 8 do not overlap. As a result, the areas where the pins of the laminated first winding 2 and the second winding 5 apply pressure are staggered, avoiding the problem of pressure concentration caused by the pins acting on the same position of the winding at the same time, improving the reliability of the device, and also helping to make the overall compression of the first winding 2 and the second winding 5 more uniform, ensuring that the magnetic device has a smaller winding volume, thereby improving the overall performance of the magnetic device.

[0068] The first winding 2 and the second winding 5 of this application are formed by laminating coils 1 in a pressing manner. Adjacent coils 1 in the first winding 2 and the second winding 5 have a pressing gap, which is ≤10% of the thickness of the coil 1. This design ensures tightness between the windings, reduces vibration and loosening during operation, increases the mechanical strength of the winding structure, and reduces distributed capacitance and leakage flux by controlling the pressing gap to ≤10% of the coil 1 thickness. This improves the electromagnetic coupling efficiency of the first winding 2 and the second winding 5, making the electrical performance of the magnetic device more stable. Simultaneously, the tight coil layout enhances the thermal conductivity between the windings, aids in rapid heat dissipation, and prevents overheating of the coils under high loads. Therefore, the pressing gap of ≤10% of the coil 1 thickness improves the heat dissipation capacity, mechanical strength, and device performance of the first winding 2 and the second winding 5.

[0069] In one embodiment, there is a compression gap between adjacent coils 1 in the first winding 2 and the second winding 5, the compression gap being 3%, 5%, or 6% of the thickness of the coil 1.

[0070] In one embodiment, the first sealant 4 covers an area ≥10% of the surface area of ​​the first winding 2, and the second sealant 7 covers an area ≥10% of the surface area of ​​the second winding 5. It can be understood that the first sealant 4 and the second sealant 7 are formed by injection molding in one step, providing electrical insulation protection for the first winding 2 and the second winding 5. When the first sealant 4 partially wraps the first winding 2 and the second sealant 7 partially wraps the second winding 5, the heat dissipation and insulation balance of the windings can be balanced, thereby improving the overall performance of the magnetic device.

[0071] In one embodiment, the thickness of the first sealant 4 and / or the second sealant 7 is ≥0.3mm. Based on this thickness limitation, the insulation performance and mechanical strength of the magnetic device are guaranteed. That is, the first sealant 4 and / or the second sealant 7 with a thickness of ≥0.3mm can provide more reliable electrical insulation protection, especially in high-voltage or high-frequency application scenarios. This helps to prevent arcing or partial discharge phenomena, avoid insulation failure, and enhance the mechanical support and protection of the first winding 2 and the second winding 5. It can effectively prevent damage caused by external forces, vibration or thermal expansion and contraction.

[0072] In one embodiment, the thickness of the first sealing compound 4 and / or the second sealing compound 7 is 0.3 mm, ensuring the miniaturization of the magnetic device as well as reliable electrical insulation and durability.

[0073] It should be noted that the injection molding materials of this application include at least one of polyethylene terephthalate, acrylonitrile-butadiene-styrene copolymer, polyamide, or polycarbonate. Furthermore, the injection molding materials of the first sealant 4 and the second sealant 7 are different. For example, the first sealant 4 is formed by one-time injection molding of polyethylene terephthalate, and the second sealant 7 is formed by one-time injection molding of polyamide. That is, by using different injection molding materials, the insulation and heat dissipation effects of the first sealant 4 and the second sealant 7 are improved. For example, polyethylene terephthalate (PET) has excellent heat resistance, abrasion resistance, mechanical strength, and electrical insulation properties. PET exhibits good performance and dimensional stability, maintaining its properties over a wide temperature range. It is heat-resistant, has strong anti-aging capabilities, and also possesses good chemical and moisture resistance. Acrylonitrile-butadiene-styrene copolymer (ABS) has good impact resistance and toughness. Polyamide (PA) is tough, with good electrical insulation and heat resistance. Polycarbonate (PC) is impact-resistant, heat-resistant, has excellent electrical insulation and heat resistance, and possesses good optical transparency and mechanical strength. Therefore, using PC as an injection molding material can effectively encapsulate the windings, improving the structural strength and insulation strength of magnetic devices.

[0074] Of course, in some embodiments, in addition to the first sealing compound 4 and the second sealing compound 7, the magnetic device may also have a sealing compound 10 and an extended sealing compound 12, etc., in which case the injection molding materials of the first sealing compound 4, the second sealing compound 7, the sealing compound 10 and the extended sealing compound 12 are different.

[0075] In summary, the method for fabricating a plastic-encapsulated magnetic device of this application involves the following steps: First winding 2 is formed by laminating and pressing a portion of coil 1; First winding 2 is injection molded once to form a first encapsulant 4; First encapsulant 4 encapsulates or partially encapsulates the area of ​​first winding 2 excluding the first ejector pin positioning area 3; A portion of coil 1 is laminated and pressed onto the first encapsulant 4 to form a second winding 5; Second winding 5 is injection molded once to form a second encapsulant 7; Second encapsulant 7 encapsulates or partially encapsulates the first encapsulant 4 and the area of ​​second winding 5 excluding the second ejector pin positioning area 6; and First winding 2 and Second winding 5 are assembled in the accommodating cavity 9 of the magnetic core body 8. This constructs an integrated structure of the plastic-encapsulated magnetic device, improves the insulation withstand voltage between the device windings, ensures a smaller device size and excellent heat dissipation, and enhances the mechanical stability and insulation capability of the magnetic device.

[0076] It should be noted that the plastic-encapsulated magnetic device of this application has a withstand voltage of ≥4000VAC and a partial discharge of ≤10PC (picocoulombs) under high frequency and high voltage.

[0077] This embodiment also discloses a plastic-encapsulated magnetic device, which can be fabricated using any of the foregoing embodiments. (Refer to...) Figures 2-8 The encapsulated magnetic device includes: a magnetic core body 8, with a cavity 9 inside the magnetic core body 8; several coils 1, some of the coils 1 are stacked and pressed together to form a first winding 2, the outer surface of the first winding 2 has multiple first pin positioning areas 3; a first sealing compound 4, the first sealing compound 4 wraps or partially wraps the area of ​​the first winding 2 excluding the first pin positioning areas 3, some of the coils 1 are stacked and pressed together on the first sealing compound 4 to form a second winding 5, the outer surface of the second winding 5 has multiple second pin positioning areas 6; a second sealing compound 7, the second sealing compound 7 wraps or partially wraps the first sealing compound 4, and wraps or partially wraps the area of ​​the second winding 5 excluding the second pin positioning areas 6; wherein the first winding 2 and the second winding 5 are connected in the cavity 9.

[0078] The first winding 2 and the second winding 5 of the plastic-encapsulated magnetic device are layered and wrapped by the first sealing compound 4 and the second sealing compound 7 through a single injection molding process, thereby constructing an integrated structure of the plastic-encapsulated magnetic device, improving the insulation withstand voltage between the device windings, ensuring the small size of the device and excellent heat dissipation, and enhancing the mechanical stability and insulation capability of the magnetic device.

[0079] For other working principles and processes of the encapsulated magnetic devices of this application, please refer to the description of the preparation method of the encapsulated magnetic devices in the foregoing embodiments of the present invention, which will not be repeated here.

[0080] The above provides a detailed description of a plastic-encapsulated magnetic device and its fabrication method. Specific examples have been used to illustrate the principles and implementation methods of this application. It should be noted that the descriptions of each embodiment in this application have different focuses; parts not described in detail in a particular embodiment can be referred to in the relevant descriptions of other embodiments.

[0081] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. The technical features of the technical solution of this application can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are also included within the patent protection scope of this application, as long as the combination of these technical features does not contradict each other.

Claims

1. A method for fabricating a plastic-encapsulated magnetic device, characterized in that, include: A plurality of coils are provided, and the coils are stacked in a pressed part to form a first winding. The outer surface of the first winding has a plurality of first ejector pin positioning areas as injection molding positioning points. The first winding is injection molded with injection molding material to form a first sealing compound. The first sealing compound covers or partially covers the area of ​​the first winding excluding the first ejector pin positioning area. The coils partially stacked on the first sealant form a second winding, and the outer surface of the second winding has a plurality of second ejector pin positioning areas as injection molding positioning points; The second winding is injection molded once using the injection molding material to form a second sealing material. The second sealing material wraps or partially wraps the first sealing material, and wraps or partially wraps the area of ​​the second winding excluding the second ejector pin positioning area. The second sealant is formed by at least one injection molding process using the injection molding material, wherein the sealant encapsulates the second sealant, the second winding, the first sealant, and the first winding. The first winding and the second winding are assembled in the accommodating cavity of the magnetic core body, and the vertical projection areas of the first ejector pin positioning area and the second ejector pin positioning area relative to the magnetic core body are not in the same position.

2. The method for fabricating a plastic-encapsulated magnetic device as described in claim 1, characterized in that, Before assembling the first winding and the second winding into the receiving cavity of the magnetic core body, the method further includes: The coils that are partially laminated on the second sealant form an extended winding, and the outer surface of the laminated extended winding has a plurality of extended pin positioning areas. The extended winding is injection molded once using the injection molding material to form an extended sealing body. The extended sealing body wraps or partially wraps the second sealing body, and wraps or partially wraps the area of ​​the extended winding excluding the extended ejector pin positioning area.

3. The method for fabricating a plastic-encapsulated magnetic device as described in claim 1, characterized in that, The accommodating cavity of the magnetic core body is provided with a magnetic post, and the first winding and the second winding are sleeved and connected to the magnetic post. The first winding has a first lead end, and the second winding has a second lead end. The first lead end and the second lead end extend towards each other outside the magnetic core body.

4. The method for fabricating a plastic-encapsulated magnetic device as described in claim 1, characterized in that, Multiple first ejector pin positioning areas are evenly arranged on the outer surface of the first winding, and multiple second ejector pin positioning areas are evenly arranged on the outer surface of the second winding.

5. The method for fabricating a plastic-encapsulated magnetic device as described in claim 1, characterized in that, There is a compression gap between adjacent coils in the first winding and the second winding, wherein the compression gap is ≤10% of the thickness of the coil.

6. The method for fabricating a plastic-encapsulated magnetic device as described in claim 1, characterized in that, The first sealant covers an area of ​​≥10% of the surface area of ​​the first winding, and the second sealant covers an area of ​​≥10% of the surface area of ​​the second winding.

7. The method for fabricating a plastic-encapsulated magnetic device as described in claim 1, characterized in that, The thickness of the first sealant and / or the second sealant is ≥0.3mm.

8. The method for fabricating a plastic-encapsulated magnetic device as described in claim 1, characterized in that, The injection molding material includes at least one of polyethylene terephthalate, acrylonitrile-butadiene-styrene copolymer, polyamide or polycarbonate, and the injection molding materials of the first sealant and the second sealant are different.

9. A plastic-encapsulated magnetic device, manufactured using the method for preparing a plastic-encapsulated magnetic device according to any one of claims 1-8, characterized in that, include: A magnetic core body, wherein a receiving cavity is formed inside the magnetic core body; Several coils, some of which are stacked and pressed together to form a first winding, the outer surface of the first winding having multiple first pin positioning areas; The first sealing material covers or partially covers the area of ​​the first winding excluding the first ejector pin positioning area. The coils stacked on the first sealing material constitute the second winding. The outer surface of the second winding has multiple second ejector pin positioning areas. The second sealing material wraps or partially wraps the first sealing material, and wraps or partially wraps the area of ​​the second winding excluding the second ejector pin positioning area; The first winding and the second winding are connected in the accommodating cavity.

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