A planar transformer and a method of manufacturing the same

Abstract

The application discloses a planar transformer and a manufacturing method thereof. The planar transformer comprises a magnetic core limiting mechanism and at least one pair of output winding assembly. The magnetic core limiting mechanism comprises an upper magnetic core and a lower magnetic core. Half of the output winding assemblies are arranged in the upper magnetic core, and the other half of the output winding assemblies are arranged in the lower magnetic core. The output winding assemblies in the upper magnetic core and the lower magnetic core are symmetrically arranged and coaxially arranged. The output winding assemblies are bonded between adjacent output winding assemblies. Each output winding assembly comprises a primary winding coil and a secondary winding assembly. The primary winding coil and the secondary winding assembly are coaxial and bonded. Each secondary winding assembly is provided with an outgoing busbar. The outgoing busbar is provided with a positioning through hole. The unreliable process of high-temperature soldering can be avoided, the production cost of the planar transformer is reduced, the reliability of the product is improved, and the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, specifically to a planar transformer and its manufacturing method. Background Technology

[0002] Vehicle-mounted DC-DC power modules have strict requirements for installation dimensions and fit due to their special usage environment. Therefore, the structure of planar transformers is usually quite special and complex, which makes the manufacturing process of planar transformers relatively complex, resulting in low production efficiency and quality of existing technologies.

[0003] The existing planar transformer output winding leads to the copper busbars require two transfers and are connected by high-temperature soldering. However, the soldering process has the following defects: (1) damages the winding insulation layer and reduces product reliability; (2) may lead to poor soldering, false soldering, and sludge, affecting product quality; (3) the soldering tooling structure is complex, the processing is difficult and the precision is hard to guarantee. The tooling components are quickly damaged during the high-temperature soldering process and the replacement cost is high, resulting in the product having no competitive advantage; (4) low production efficiency.

[0004] With the continued booming development of the new energy industry, the market demand for planar transformers is increasing day by day. In order to adapt to the needs of mass production, it is urgent to make improvements from the design considerations of the planar transformer body structure, eliminate the unreliable process of high-temperature soldering, reduce the material cost of structural components, improve product reliability and increase production efficiency. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a planar transformer and its manufacturing method, which eliminates the unreliable process of high-temperature soldering, thereby reducing the production cost of the planar transformer, improving product reliability, and increasing production efficiency.

[0006] The specific technical solution of the present invention is as follows:

[0007] On one hand, the present invention provides a planar transformer, including a core limiting mechanism and at least one pair of output winding assemblies;

[0008] The magnetic core limiting mechanism includes an upper magnetic core and a lower magnetic core. Half of the output winding assemblies are located in the upper magnetic core, and the other half are located in the lower magnetic core. The output winding assemblies in the upper and lower magnetic cores are symmetrically arranged and coaxially arranged. Adjacent output winding assemblies are bonded together.

[0009] Each of the output winding assemblies includes a primary winding coil and a secondary winding coil assembly. The primary winding coil and the secondary winding coil assembly are coaxial and bonded together. Each of the secondary winding coil assemblies has its own lead-out busbar, and each lead-out busbar has a positioning through hole.

[0010] Preferably, the output winding assembly is provided in two pairs. The primary winding coils of the two middle output winding assemblies are bonded together with epoxy adhesive. The secondary winding assembly of each output winding assembly includes a secondary winding unit. The secondary winding unit is planar spiral. The outermost ring of the spiral is bent to form a lead-out busbar. The center of the spiral serves as a limiting through hole for the magnetic core limiting mechanism to limit. Each primary winding coil has a limiting through hole of the same diameter.

[0011] Preferably, each of the secondary coil winding assemblies includes two secondary coil winding units;

[0012] In each secondary coil winding assembly within the upper magnetic core, the busbar of one secondary coil winding unit is located on the left, and the busbar of the other secondary coil winding unit is located in the middle;

[0013] In each secondary coil winding assembly within the lower magnetic core, the busbar of one secondary coil winding unit is located on the right side, and the busbar of the other secondary coil winding unit is located in the middle.

[0014] The positioning through holes of each lead-out busbar on the left are coaxial, the positioning through holes of each lead-out busbar in the middle are coaxial, and the positioning through holes of each lead-out busbar on the right are coaxial.

[0015] Preferably, the bending path of each secondary coil winding unit with each lead-out busbar located in the middle is: a downward bend of 90° and an outward bend of 90°.

[0016] The bending path of each secondary coil winding unit located on the left or right side of the busbar is: 90° downward bend - 90° outward bend - 180° inward bend.

[0017] Preferably, the plane where the positioning through hole of each of the lead-out busbars is located is parallel to the plane where the helix of its corresponding secondary coil winding unit is located.

[0018] Preferably, each of the secondary coil winding units is provided with insulating pads on both the top and bottom, and the insulating pads are bonded to the secondary coil winding unit.

[0019] Preferably, each of the secondary coil winding units includes a core made of copper, and the core is covered with a nickel layer and a tin layer in sequence.

[0020] Preferably, the core has a thickness of 1.2 mm, the nickel layer has a thickness of 1-3 μm, and the tin layer has a thickness of 3-5 μm.

[0021] Preferably, the upper and lower magnetic cores are matched and bonded together, and each includes a bottom component, a central column and two side components. The central column is fixed at the center of the bottom component, and the outer diameter of the central column matches the inner diameter of the limiting through hole, which is used to pass through the limiting through hole of the output winding assembly to limit its position. The two side components are fixed at both ends of the bottom component to limit the periphery of the output winding assembly.

[0022] On the other hand, the present invention also provides a method for manufacturing the above-mentioned planar transformer, comprising the following manufacturing steps:

[0023] S1. Use tooling to assemble each output winding assembly with the magnetic core limiting structure and then limit and lock them in place.

[0024] S2. Place the tooling and the pre-assembled planar transformer together into an oven to dry;

[0025] S3. Remove the dried planar transformer from the tooling to obtain the finished planar transformer.

[0026] Preferably, the tooling includes a base plate, a limiting groove, a boss, and a cover plate, wherein:

[0027] The limiting groove is formed on the base plate and is used to position the lower magnetic core; a fixing screw is provided on both sides of the limiting groove.

[0028] The boss is fixed on the base plate. The boss is provided with a positioning post. The positioning post is used to position the lead-out busbar. Each positioning post is provided with a threaded hole. Each threaded hole is provided with a positioning bolt that is threadedly connected to it. The positioning bolt is used to pass through the positioning through hole of the lead-out busbar and lock the lead-out busbar on the boss.

[0029] The cover plate is provided with through slots for each fixing screw to pass through. The cover plate covers the upper magnetic core and is locked in place by a wing nut.

[0030] The beneficial effects of this invention are reflected in:

[0031] This invention simplifies the production process by assembling tooling to complete most of the manufacturing processes required for planar transformers. Through interlayer adhesive application to the output winding assembly, the lead busbars are fixed in place. Precise dimensional control is achieved through tooling positioning, eliminating the need for high-temperature soldering to position the lead busbars. This shortens the production cycle, improves efficiency, and avoids damage to the primary winding and secondary insulation materials caused by high-temperature soldering, thus enhancing the reliability of the planar transformer. Furthermore, it significantly reduces power consumption, better meeting the energy-saving and consumption-reducing requirements of mass production. Compared to competitors who rely on welding copper busbars to produce such transformers, this invention offers better quality assurance and stronger market competitiveness. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0033] Figure 1 This is a schematic diagram of the planar transformer provided in Embodiment 1 of the present invention;

[0034] Figure 2 for Figure 1 The diagram shows the exploded structure of a planar transformer.

[0035] Figure 3 for Figure 1 The diagram shows an exploded view of the output winding assembly of a planar transformer.

[0036] Figure 4 for Figure 1 The secondary winding unit of the planar transformer shown has the following bending path: a 90° downward bend followed by a 90° outward bend.

[0037] Figure 5 for Figure 1 The secondary winding unit of the planar transformer shown has the following bending path: 90° downward bend - 90° outward bend - 180° inward bend.

[0038] Figure 6 for Figure 5 The side view of the secondary coil winding unit shown;

[0039] Figure 7 for Figure 1 The diagram shows the structure of the lower magnetic core of the planar transformer.

[0040] Figure 8 This is a schematic diagram of the tooling provided in Embodiment 2 of the present invention;

[0041] Figure 9 This is a schematic diagram of the tooling provided in Embodiment 2 of the present invention.

[0042] In the attached diagram, 1-Magnetic core limiting mechanism, 11-Upper magnetic core, 12-Lower magnetic core, 121-Bottom component, 122-Middle column, 123-Side component, 2-Output winding assembly, 21-Primary winding coil, 22-Secondary winding assembly, 221-Secondary winding unit, 222-Lead busbar, 223-Insulating pad, 224-Positioning through hole, 225-Limiting through hole, 3-External copper terminal, 4-Insulating pad, 51-Bottom plate, 52-Boss, 521-Positioning post, 522-Positioning bolt, 523-Threaded hole, 53-Limiting groove, 54-Cover plate, 55-Fixing screw, 56-Wing nut. Detailed Implementation

[0043] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0044] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0045] Example 1

[0046] This embodiment provides a planar transformer, such as Figures 1 to 3 As shown, it includes a magnetic core limiting mechanism 1, an external copper terminal 3, and at least one pair of output winding assemblies 2;

[0047] The magnetic core limiting mechanism 1 includes an upper magnetic core 11 and a lower magnetic core 12. Half of the output winding assemblies 2 are located in the upper magnetic core 11, and the other half of the output winding assemblies 2 are located in the lower magnetic core 12. The output winding assemblies 2 in the upper magnetic core 11 and the lower magnetic core 12 are symmetrically arranged and coaxially arranged. Adjacent output winding assemblies 2 are bonded together with epoxy adhesive.

[0048] Each output winding assembly 2 includes a primary winding coil 21 and a secondary winding coil assembly 22. The primary winding coil 21 and the secondary winding coil assembly 22 are coaxial and bonded together with epoxy adhesive. Each secondary winding coil assembly 22 has its own lead-out busbar 222, and each lead-out busbar 222 has a positioning through hole 224.

[0049] In this embodiment, as Figure 2As shown, the output winding assembly 2 is provided with two pairs. The primary winding coils 21 of the two middle output winding assemblies 2 are bonded together with epoxy adhesive. Each secondary winding coil assembly 22 of the output winding assembly 2 includes a secondary winding coil unit 221. The secondary winding coil unit 221 is a planar spiral shape. The outermost ring end of the spiral shape is bent to form a lead-out busbar 222. The center of the spiral shape serves as a limiting through hole 225 for the magnetic core limiting mechanism 1 to limit. Each primary winding coil 21 has a limiting through hole 225 of the same diameter.

[0050] In this embodiment, as Figures 2 to 3 As shown, each secondary coil winding assembly 22 includes two secondary coil winding units 221;

[0051] In each secondary coil winding assembly 22 within the upper magnetic core 11, the busbar 222 of one secondary coil winding unit 221 is located on the left side, and the busbar 222 of the other secondary coil winding unit 221 is located in the middle.

[0052] In each secondary coil winding assembly 22 within the lower magnetic core 12, the busbar 222 of one secondary coil winding unit 221 is located on the right side, and the busbar 222 of the other secondary coil winding unit 221 is located in the middle.

[0053] like Figure 1 As shown, the positioning through holes 224 of each lead-out busbar 222 on the left side are coaxial, the positioning through holes 224 of each lead-out busbar 222 in the middle are coaxial, and the positioning through holes 224 of each lead-out busbar 222 on the right side are coaxial. This design makes the lead-out busbars 222 on the left and right sides form the parallel connection point of the planar transformer, and the lead-out busbar 222 in the middle forms the series connection point of the planar transformer.

[0054] To further facilitate processing and production, in this embodiment, as follows: Figures 1 to 4 As shown, the bending path of the secondary coil winding unit 221 located in the middle of each lead-out busbar 222 is: a downward bend of 90° followed by an outward bend of 90°; as shown... Figures 1 to 3 as well as Figures 5 to 6 As shown, the bending path of the secondary coil winding unit 221 of each lead-out busbar 222 located on the left or right side is: 90° downward bend - 90° outward bend - 180° inward bend; through this design, the total thickness of each column of lead-out busbars 222 after stacking is the same during the production process, such as... Figure 1 As shown, all are 4 layers thick, and the top surface is flat, which makes them easy to process and the resulting products are more beautiful and practical.

[0055] In this embodiment, as Figures 1 to 5As shown, the plane where the positioning through hole 224 of each lead-out busbar 222 is located is parallel to the spiral plane of its corresponding secondary coil winding unit 221. For the secondary coil winding unit 221 with a bending path of 90° downward bending - 90° outward bending - 180° inward bending, its end actually has two identical positioning through holes 224. After the final step of bending inward by 180°, the two positioning through holes 224 completely overlap and fit tightly together.

[0056] In this embodiment, as Figure 3 As shown, each secondary coil winding unit 221 is provided with an insulating pad 223 on both the top and bottom. The insulating pad 223 is bonded to the secondary coil winding unit 221 with epoxy adhesive. The upper magnetic core 11, the lower magnetic core 12 and the output winding assembly 2 are bonded with an insulating pad 4 with epoxy adhesive.

[0057] In this embodiment, each secondary coil winding unit 221 includes a core made of copper, with a nickel layer and a tin layer sequentially coated on the outside of the core. The thickness of the core is preferably 1.2 mm, the thickness of the nickel layer is preferably 1-3 μm, and the thickness of the tin layer is preferably 3-5 μm.

[0058] In this embodiment, the upper magnetic core 11 and the lower magnetic core 12 are matched and bonded together. The upper magnetic core 11 and the lower magnetic core 12 each include a bottom component 121, a central post 122, and two side components 123, as shown below. Figure 7 As shown, the center post 122 is fixed at the center of the bottom component 121. The outer diameter of the center post 122 matches the inner diameter of the limiting through hole 225 and is used to pass through the limiting through hole 225 of the output winding assembly 2 to limit it. The two side components 123 are fixed at both ends of the bottom component 121 to limit the periphery of the output winding assembly 2. The side component 123 is curved on the side closest to the center post 122 and the curved surface matches the periphery of the output winding assembly 2.

[0059] The planar transformer provided in this embodiment can meet the original installation size requirements and eliminate the need for soldering copper busbars, thereby avoiding the damage to the primary winding and secondary insulation materials of the transformer caused by high-temperature soldering, improving the reliability of the transformer, while greatly reducing the power consumption of production, making it more energy-efficient and environmentally friendly, and reducing the production cost of the product.

[0060] Example 2

[0061] This embodiment provides a method for manufacturing the planar transformer of Embodiment 1, including the following manufacturing steps:

[0062] S1. Use tooling to assemble each output winding assembly 2 with the magnetic core limiting structure and limit and lock them;

[0063] S2. Place the tooling and the pre-assembled planar transformer together into an oven to dry;

[0064] S3. Remove the dried planar transformer from the tooling to obtain the finished planar transformer.

[0065] like Figures 8 to 9 As shown, the tooling includes a base plate 51, a limiting groove 53, a boss 52, and a cover plate 54, wherein:

[0066] The limiting groove 53 is formed on the base plate 51 and matches the shape and size of the bottom of the lower magnetic core 12. It can be used to position the lower magnetic core 12. Fixing screws 55 are provided on both sides of the limiting groove 53. It should be noted that a tooling can be designed as multiple stations. For example, this embodiment is a two-station tooling. Each limiting groove 53 can be arranged in a row, and a fixing screw 55 can be set between adjacent limiting grooves 53.

[0067] The boss 52 is detachably fixed to the base plate 51. One boss 52 is required for each workstation. The boss 52 is provided with positioning pins 521. The positioning pins 521 are used to position the lead-out busbar 222. Each positioning pin 521 is provided with a threaded hole 523. Each threaded hole 523 has a positioning bolt 522 that is threadedly connected to it. The positioning bolt 522 is used to pass through the positioning through hole 224 of the lead-out busbar 222 to lock the lead-out busbar 222 onto the boss 52. In this embodiment, each boss 52 is provided with three positioning pins 521, which are used to position and lock the lead-out busbar 222 located on the left, middle and right sides respectively.

[0068] The cover plate 54 is provided with through slots for each fixing screw 55 to pass through. The cover plate 54 covers the upper magnetic core 11 and is locked in place by a wing nut 56.

[0069] Step S1 specifically includes the following operations:

[0070] First, assemble the tooling and boss 52. Figure 8 The structure shown is followed by placing the lower magnetic core 12 in the limiting groove 53 of the tooling, then stacking the output winding assembly 2 on the central post 122 of the lower magnetic core 12, and fitting the lead-out busbar 222 onto the corresponding limiting post of the boss 52. Epoxy glue is evenly applied between each layer of output winding assembly 2. The upper magnetic core 11 is then assembled, and the upper magnetic core 11 and lower magnetic core 12 are bonded together with epoxy glue. After bonding, the lead-out busbar 222 is locked onto the boss 52 using limiting bolts to prevent displacement of the lead-out busbar 222. Finally, the cover plate 54 is passed through each fixing screw 55 and placed on the upper magnetic core 11, and locked using a wing nut 56, forming a structure as shown. Figure 9 The structure shown prevents the magnetic core limiting mechanism 1 from shifting up, down, left, or right.

[0071] The tooling provided in this embodiment is significantly simplified in structure compared to the tooling used in the prior art. Most of the processes required for the production of planar transformers can be completed by assembling the tooling, thus simplifying the production process. By applying adhesive between the two layers of the output winding assembly, the lead busbar 222 is fixed in place. The tooling provides precise positioning and the dimensions are precisely controlled, eliminating the need for high-temperature soldering to position the lead busbar 222. This shortens the production cycle, improves production efficiency, and avoids damage to the primary winding and secondary insulation materials of the transformer caused by high-temperature soldering, thereby improving the reliability of the planar transformer. At the same time, the power consumption is greatly reduced, better meeting the energy-saving and consumption-reducing requirements of mass production. Compared with the designs of competitors that rely on welding copper busbars to produce such transformers, this method provides better quality assurance and stronger market competitiveness.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A planar transformer, characterized in that: Includes a core limiting mechanism and at least one pair of output winding assemblies; The magnetic core limiting mechanism includes an upper magnetic core and a lower magnetic core. Half of the output winding assemblies are located in the upper magnetic core, and the other half are located in the lower magnetic core. The output winding assemblies in the upper and lower magnetic cores are symmetrically arranged and coaxially arranged. Adjacent output winding assemblies are bonded together. Each of the output winding assemblies includes a primary winding coil and a secondary winding coil assembly. The primary winding coil and the secondary winding coil assembly are coaxial and bonded together. Each of the secondary winding coil assemblies has its own lead-out busbar, and each lead-out busbar has a positioning through hole. The output winding assembly is provided in two pairs. The primary winding coils of the two middle output winding assemblies are bonded together with epoxy adhesive. The secondary winding assembly of each output winding assembly includes a secondary winding unit. The secondary winding unit is a planar spiral shape. The outermost ring of the spiral shape is bent to form a lead-out busbar. The center of the spiral shape serves as a limiting through hole for the magnetic core limiting mechanism to limit. Each primary winding coil has a limiting through hole of the same diameter. Each of the aforementioned secondary coil winding assemblies includes two secondary coil winding units; In each secondary coil winding assembly within the upper magnetic core, the busbar of one secondary coil winding unit is located on the left, and the busbar of the other secondary coil winding unit is located in the middle; In each secondary coil winding assembly within the lower magnetic core, the busbar of one secondary coil winding unit is located on the right side, and the busbar of the other secondary coil winding unit is located in the middle. The positioning through holes of each lead-out busbar on the left are coaxial, the positioning through holes of each lead-out busbar in the middle are coaxial, and the positioning through holes of each lead-out busbar on the right are coaxial. The bending path of each secondary coil winding unit located in the middle of each lead-out busbar is: 90° downward bend - 90° outward bend; The bending path of each secondary coil winding unit located on the left or right side of the lead busbar is: 90° downward bend - 90° outward bend - 180° inward bend; The upper and lower magnetic cores are matched and bonded together, and each includes a bottom component, a central column, and two side components. The central column is fixed at the center of the bottom component, and the outer diameter of the central column matches the inner diameter of the limiting through hole, which is used to pass through the limiting through hole of the output winding assembly to limit its position. The two side components are fixed at both ends of the bottom component to limit the periphery of the output winding assembly.

2. The planar transformer according to claim 1, characterized in that: The plane containing the positioning through hole of each of the aforementioned lead-out busbars is parallel to the plane containing the helix of its corresponding secondary coil winding unit.

3. The planar transformer according to claim 1, characterized in that: Each of the secondary coil winding units is provided with insulating pads on both the top and bottom, and the insulating pads are bonded to the secondary coil winding unit.

4. The planar transformer according to claim 1, characterized in that: Each of the secondary coil winding units includes a core made of copper, and the core is covered with a nickel layer and a tin layer in sequence.

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