Miniature waterproof fan and manufacturing process thereof

Abstract

The invention discloses a miniature waterproof fan and a manufacturing process thereof.The fan comprises a base, a heat absorption bottom, a flexible circuit board assembly, a coil assembly, an impeller assembly, cooling fins, a top cover and a lead frame, and the cooling fins, the flexible circuit board assembly and the coil assembly are arranged in an inner cavity of the base; the lead frame and the heat absorption bottom are integrally formed on the base through an insert injection molding process, and one end of the lead frame extends to an inner cavity of the base and is welded to the flexible circuit board assembly through a thermocompression welding process. According to the invention, the lead frame, the heat absorption bottom and the base form an integrally formed structure through an insert injection molding process, so that a traditional FPC lead-out opening structure on the base is thoroughly eliminated, and the waterproof difficulty is fundamentally solved. Meanwhile, the lead frame, the heat absorption bottom and the base are combined more firmly through the insert injection molding technology, gaps generated by assembly of components in a traditional structure are eliminated, the waterproof performance is further improved, the overall structural strength can be effectively enhanced, and falling impact can be effectively resisted; the surface of the end part of the lead frame is tinned and is welded with the FPC in combination with a thermocompression welding process, so that the welding connection is ensured to be firmer and more reliable, and the anti-vibration effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fans, and in particular to a miniature waterproof fan and a manufacturing process thereof. Background Art

[0002] As smart terminal products (such as laptops, tablets and mobile phones) continue to develop in the direction of being lighter and thinner, their heat dissipation components - micro waterproof fans are also facing higher design requirements. On the one hand, micro waterproof fans need to achieve efficient heat dissipation in a limited space; on the other hand, since accidental liquid splashing occurs frequently during daily use, the waterproof performance of micro waterproof fans has become a crucial design consideration.

[0003] After in-depth research, it was found that the key to waterproofing the micro waterproof fan lies in the lead-out structure of the FPC (flexible printed circuit board) and the combination structure of the heat-absorbing bottom and the base. The FPC is responsible for electrically connecting the inside of the fan to the external system, and its lead-out part is often the focus of the waterproof design. However, the traditional FPC lead-out structure has many openings, which makes waterproofing a difficult point. In order to achieve a waterproof effect, an additional dispensing process is usually required, but this not only increases production costs, but may also cause dispensing failure due to vibration. Therefore, the development of a waterproof and vibration-resistant FPC lead-out structure has become an industry problem. At the same time, how to ensure that the heat-absorbing bottom and the base are both tightly combined and waterproof is also a key issue that needs to be solved urgently. Solving these problems is crucial to improving the performance of micro waterproof fans. Summary of the invention

[0004] In view of the above-mentioned deficiencies, an object of the present invention is to provide a waterproof and vibration-resistant miniature waterproof fan and a manufacturing process thereof.

[0005] To achieve the above purpose, the technical solution provided by the present invention is:

[0006] A miniature waterproof fan comprises a base, a heat absorbing bottom, a flexible circuit board assembly, a coil assembly, an impeller assembly, heat dissipation fins, a top cover and a lead frame, wherein the heat dissipation fins, the flexible circuit board assembly and the coil assembly are arranged in the inner cavity of the base, the impeller assembly is arranged on the middle tube of the base, the top cover is covered on the base, the lead frame and the heat absorbing bottom are integrally formed on the base by an insert injection molding process, one end of the lead frame extends to the inner cavity of the base and is welded to the flexible circuit board assembly by a hot pressing welding process, and the other end of the lead frame extends to the outside of the base.

[0007] As a preferred solution of the present invention, the end surface of the lead frame is tin-plated, which is more conducive to the implementation of the hot pressing welding process.

[0008] As a preferred solution of the present invention, a dovetail groove is provided at the edge of the heat absorbing bottom. The dovetail groove structure enables the heat absorbing bottom to be tightly combined with the plastic base, significantly improving the anti-drop performance of the module.

[0009] As a preferred solution of the present invention, waterproof glue is applied to the base at the position of the hot pressing welding point corresponding to the lead frame through a glue dispensing process, so as to effectively block the intrusion of liquid and improve the waterproof level.

[0010] As a preferred solution of the present invention, the base is provided with a groove extending along the outer contour line of the base corresponding to the inner side of the edge of the heat absorbing bottom, and waterproof glue is applied to the groove by glue dispensing technology. The groove is designed to provide a space for the glue to further enhance the waterproof effect.

[0011] As a preferred solution of the present invention, the heat absorbing bottom is embedded in the bottom surface of the base, and the heat dissipation fins are in contact with the heat absorbing bottom. The heat dissipation fins can increase the heat dissipation area and improve the heat dissipation efficiency. At the same time, the direct contact between the heat absorbing bottom and the heat dissipation fins ensures that the heat can be quickly transferred from the heat absorbing bottom to the heat dissipation fins and dissipated through the rotation of the fan.

[0012] As a preferred solution of the present invention, a hook ear is provided at the edge of the top cover, and a hook foot matching the hook ear is provided on the base. By inserting the hook foot into the hook ear, it is not only convenient to assemble, simplifies the assembly process, reduces production costs, and improves production efficiency, but also ensures that the connection between the top cover and the base is more firm and reliable, prevents loosening or falling off due to vibration, and improves the overall drop resistance performance.

[0013] As a preferred solution of the present invention, an elastic waterproof gasket is provided between the top cover and the base, which can ensure the sealing between the top cover and the base and effectively prevent liquid from penetrating. A conductive foam is provided between the top cover and the heat dissipation fins. The conductive foam has the functions of conducting electricity and isolating vibrations, can effectively absorb impact force, protect internal components, and extend the service life of the product.

[0014] As a preferred solution of the present invention, the miniature waterproof fan of the present invention has a length of ≤25mm, a width of ≤25mm, and a height of ≤6mm. It is thin and compact, meeting the requirements for miniaturization of equipment.

[0015] A manufacturing process of a miniature waterproof fan comprises the following steps:

[0016] (1) Injection molding: The lead frame and the heat absorbing bottom are positioned and placed in an injection mold in advance, and then the molten material is injected through an insert molding process to bond and solidify with the lead frame and the heat absorbing bottom to form an integrated structure base;

[0017] (2) Fin welding: brush solder paste on the bottom surface of the heat sink fin, put it into the inner cavity of the base and weld it to the heat absorbing bottom;

[0018] (3) Hot-press welding: The flexible circuit board assembly and the coil assembly are installed into the inner cavity of the base, and one end of the lead frame is welded to the flexible circuit board assembly by a hot-press welding process;

[0019] (4) Applying waterproof glue: Apply waterproof glue to the matching positions of the base, the flexible circuit board assembly and related components;

[0020] (5) Assembly of other parts: Install the wear-resistant sheet and bearing on the middle tube of the base;

[0021] (6) Install the impeller assembly: Install the impeller assembly on the bearing;

[0022] (7) Paste the conductive foam on the top surface of the heat sink fins and install the elastic waterproof gasket on the edge of the inner cavity opening of the base;

[0023] (8) Installing the cover: snapping the top cover onto the inner cavity opening of the base to obtain a miniature waterproof fan.

[0024] The beneficial effects of the present invention are as follows: the present invention has a reasonable structural design, and the lead frame, heat-absorbing bottom and base are formed into an integrated structure through the insert injection molding process, which completely eliminates the traditional FPC lead-out opening structure on the base, and fundamentally solves the waterproof difficulty. At the same time, the insert injection molding process makes the lead frame and the heat-absorbing bottom more firmly combined with the base, which not only eliminates the gaps caused by the assembly between components in the traditional structure, further improves the waterproof performance, but also effectively enhances the overall structural strength and effectively resists the impact of falling; the end surface of the lead frame is tinned and welded to the flexible circuit board assembly by combining the hot pressing welding process, which effectively ensures that the welding connection is more firm and reliable, and improves the anti-vibration effect. The manufacturing process of the micro waterproof fan provided by the present invention is simple and easy to implement, and can quickly produce a micro waterproof fan that is both waterproof and vibration-resistant.

[0025] The present invention is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a three-dimensional structural schematic diagram of the present invention.

[0027] Figure 2 It is a cross-sectional structural schematic diagram of the present invention.

[0028] Figure 3 It is a schematic diagram of the decomposition structure of the present invention.

[0029] Figure 4 The bottom structure of the present invention is schematically shown in FIG. Figure 1.

[0030] Figure 5 The bottom structure of the present invention is schematically shown in FIG. Figure 2 . DETAILED DESCRIPTION

[0031] For example, see Figures 1 to 5 , a miniature waterproof fan provided in this embodiment includes a base 1, a heat-absorbing bottom 2, a flexible circuit board assembly 3, a lead frame 4, a coil assembly 5, an impeller assembly 6, a heat dissipation fin 7 and a top cover 8. In this embodiment, the length, width and height of the miniature waterproof fan of the present invention are 15*15*4.5mm. It is thin in thickness and small in size, meeting the requirements for miniaturization and miniaturization of equipment. In other embodiments, the length of the drop-resistant miniature waterproof heat dissipation module of the present invention can be ≤25mm, the width can be ≤25mm, and the height can be ≤6mm.

[0032] The lead frame 4 and the heat absorbing bottom 2 are integrally formed on the base 1 through an insert injection molding process. Specifically, the heat absorbing bottom 2 is embedded in the bottom surface of the base 1, and a dovetail groove 21 is preferably provided at the edge of the heat absorbing bottom 2. The dovetail groove 21 structure allows the heat absorbing bottom 2 to be tightly combined with the plastic base 1, significantly improving the anti-drop performance of the module. A groove 11 extending along the outer contour line of the base 1 corresponding to the inner side of the edge of the heat absorbing bottom 2 is provided, and the groove 11 is designed to provide a space for accommodating glue. Waterproof glue can be applied to the groove 11 through a glue dispensing process to further enhance the waterproof effect.

[0033] The flexible circuit board assembly 3 and the coil assembly 5 are arranged in the inner cavity of the base 1, and the flexible circuit board assembly 3 includes an FPC and electronic components arranged on the FPC. The lead frame 4 is embedded in the side wall of the base 1, wherein one end of the lead frame 4 extends to the inner cavity of the base 1 and is hot-pressed and welded with the FPC of the flexible circuit board assembly 3 through a hot-pressing welding process. Preferably, tin plating is performed on the end surface of the lead frame 4 to facilitate the hot-pressing welding process. After the hot-pressing welding process is completed, waterproof glue can be applied at the hot-pressing welding point position 12 of the base 1 corresponding to the lead frame 4 through a glue dispensing process to effectively block liquid intrusion and improve the waterproof level.

[0034] The heat dissipation fins 7 are located in the inner cavity of the base 1 and are in contact with the heat absorbing bottom 2. The heat dissipation area can be increased and the heat dissipation efficiency can be improved by the heat dissipation fins 7. At the same time, the direct contact between the heat absorbing bottom 2 and the heat dissipation fins 7 ensures that the heat can be quickly transferred from the heat absorbing bottom 2 to the heat dissipation fins 7 and dissipated through the rotation of the fan.

[0035] The top cover 8 is covered on the base 1. Preferably, an elastic waterproof gasket 10 is provided between the top cover 8 and the base 1. The elastic waterproof gasket 10 can ensure the sealing between the top cover and the base 1 and effectively prevent liquid from penetrating. A conductive foam 9 is provided between the top cover 8 and the heat dissipation fins 7. The conductive foam 9 has the functions of conductivity and vibration isolation, can effectively absorb impact force, protect internal components, and extend the service life of the product. A hook ear 81 is provided at the edge of the top cover 8, and a hook foot 13 adapted to the hook ear 81 is provided on the base 1. By clipping the hook foot 13 into the hook ear 81, not only is assembly convenient, the assembly process is simplified, the production cost is reduced, and the production efficiency is improved, but also the connection between the top cover 8 and the base 1 can be ensured to be more firm and reliable, and loosening or falling off due to vibration can be prevented, thereby improving the overall drop resistance performance.

[0036] During production, the following steps are included:

[0037] (1) Injection molding: The lead frame 4 and the heat absorbing base 2 are positioned and placed in an injection mold in advance, and then the molten plastic material is injected through an insert molding process to bond and solidify with the lead frame 4 and the heat absorbing base 2 to form an integrated base 1;

[0038] (2) Fin welding: brush solder paste on the bottom surface of the heat dissipation fin 7, then put it into the inner cavity of the base 1 and weld it to the heat absorbing bottom 2;

[0039] (3) Hot-press welding: The flexible circuit board assembly 3 and the coil assembly 5 are installed into the inner cavity of the base 1. The coil assembly 5 includes a plurality of stator coils, which are arranged in a replicating circular array on the FPC of the flexible circuit board assembly 3. The FPC has four circuit pads 31, and the inner and outer ends of the lead frame 4 are each provided with four lead pads 41. The four lead pads 41 on the inner end of the lead frame 4 are welded to the four circuit pads 31 on the FPC through a hot-press welding process; and the four lead pads 41 on the outer end of the lead frame 4 can be connected to the fan control system, thereby achieving electrical connection;

[0040] (4) Apply waterproof glue: Apply waterproof glue 20 to the matching positions of the base 1, FPC and related components, such as the hot pressing welding point position 12, etc. For specific coating positions, see Figure 4 and Figure 5 ;

[0041] (5) Assembly of other parts: install the wear-resistant sheet and bearing on the middle tube 13 of the base 1, fix the back iron 14 on the bottom surface of the base 1, etc.;

[0042] (6) Installing the impeller assembly: The impeller assembly 6 includes fan blades, a motor housing, a magnetic sheet and a shaft core, wherein the shaft core is fixed at the center of the motor housing, the fan blades are sleeved on the outer wall of the motor housing, and the magnetic sheet is arranged on the motor housing; align the shaft core on the impeller assembly 6 with the bearing and install it;

[0043] (7) Pasting cotton and installing ring: Paste conductive foam 9 on the top surface of the heat dissipation fin 7, and install an elastic waterproof gasket 10 on the edge of the inner cavity opening of the base 1;

[0044] (8) Installing the cover: snap the top cover 8 onto the inner cavity opening of the base 1, and make the hook ears 81 on the top cover 8 snap into the hook feet 13 on the base 1 to obtain a miniature waterproof fan.

[0045] The miniature waterproof fan of the present invention has the following advantages:

[0046] 1. High strength and drop resistance: The one-piece molding structure significantly enhances the overall strength and effectively resists drop impact.

[0047] 2. Excellent waterproof performance: The combination of dispensing technology and insert injection molding effectively blocks liquid intrusion and improves the waterproof level. The insert injection molding process allows the lead frame 4, heat absorbing bottom 2 and base 1 to form an integrated structure, completely eliminating the traditional FPC lead-out opening structure on the base 2, and fundamentally solving the waterproof difficulty. At the same time, the insert injection molding process makes the lead frame 4 and the heat absorbing bottom 2 and the base 1 more firmly combined, not only eliminating the gaps caused by the assembly between components in the traditional structure, but also further improving the waterproof performance.

[0048] 3. Reliable electrical connection: The surface of the lead frame 4 is tinned, and the FPC and the lead frame 4 are welded together using a hot pressing process to ensure a long-term and stable electrical connection with the FPC pad.

[0049] 4. Enhanced structural stability: The dovetail groove structure allows the heat absorbing bottom 2 to be tightly combined with the base 1, significantly improving the module's anti-drop performance.

[0050] 5. Enhanced waterproof performance: The groove design provides accommodation space for the waterproof glue 20, further enhancing the waterproof effect.

[0051] 6. Improve impact resistance and shock absorption capabilities: Add conductive foam 9 to effectively absorb impact, protect internal components, and extend product life.

[0052] 7. Reliable waterproof seal: The elastic waterproof gasket 10 ensures the sealing between the top cover 8 and the base 1, effectively preventing liquid from penetrating.

[0053] 8. Stable structural combination: The design of the hook foot 13 and the hook ear 81 ensures the tight combination of the top cover 8 and the base 1, improving the overall drop resistance performance.

[0054] 9. Simple and efficient assembly: The coordination of the hook foot 13 and the hook ear 81 and the combination with the washer simplifies the assembly process, reduces production costs and improves production efficiency.

[0055] According to the disclosure and teaching of the above specification, technicians in the field to which the present invention belongs can also change and modify the above implementation. Therefore, the present invention is not limited to the specific implementations disclosed and described above, and some modifications and changes to the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation to the present invention. As described in the above embodiments of the present invention, other fans and manufacturing processes obtained by using the same or similar structures are all within the scope of protection of the present invention.

Claims

1. A miniature waterproof fan, comprising a base, a heat absorbing bottom, a flexible circuit board assembly, a coil assembly, an impeller assembly, a heat dissipation fin and a top cover, wherein the heat dissipation fin, the flexible circuit board assembly and the coil assembly are arranged in the inner cavity of the base, the impeller assembly is arranged on the middle tube of the base, and the top cover is covered on the base, characterized in that: It also includes a lead frame, which is integrally formed on the base with a heat-absorbing bottom by an insert injection molding process. One end of the lead frame extends to the inner cavity of the base and is welded to the flexible circuit board assembly by a hot pressing welding process. The other end of the lead frame extends to the outside of the base.

2. The miniature waterproof fan according to claim 1, characterized in that: The end surface of the lead frame is tin-plated.

3. The miniature waterproof fan according to claim 1, characterized in that: A dovetail groove is provided at the edge of the heat absorbing bottom.

4. The miniature waterproof fan according to claim 1, characterized in that: Waterproof glue is coated on the base at the hot pressing welding point position corresponding to the lead frame through a glue dispensing process.

5. The miniature waterproof fan according to claim 1, characterized in that: The base is provided with a groove extending along the outer contour line of the base corresponding to the inner side of the edge of the heat-absorbing bottom, and waterproof glue is applied to the groove by a glue dispensing process.

6. The miniature waterproof fan according to claim 1, characterized in that: The heat absorbing bottom is embedded in the bottom surface of the base, and the heat dissipation fins are in contact with the heat absorbing bottom.

7. The miniature waterproof fan according to claim 6, characterized in that: A hook ear is arranged at the edge of the top cover, and a hook foot matching the hook ear is arranged on the base.

8. The miniature waterproof fan according to claim 7, characterized in that: An elastic waterproof gasket is arranged between the top cover and the base; and a conductive foam is arranged between the top cover and the heat dissipation fins.

9. The miniature waterproof fan according to claim 1, characterized in that: Its length is ≤25mm, width is ≤25mm, and height is ≤6mm.

10. A manufacturing process of the miniature waterproof fan according to any one of claims 1 to 9, characterized in that: It includes the following steps: (1) Injection molding: The lead frame and the heat absorbing bottom are positioned and placed in an injection mold in advance, and then the molten material is injected through an insert molding process to bond and solidify with the lead frame and the heat absorbing bottom to form an integrated structure base; (2) Fin welding: brush solder paste on the bottom surface of the heat sink fin, put it into the inner cavity of the base and weld it to the heat absorbing bottom; (3) Hot-press welding: The flexible circuit board assembly and the coil assembly are installed into the inner cavity of the base, and one end of the lead frame is welded to the flexible circuit board assembly by a hot-press welding process; (4) Applying waterproof glue: Apply waterproof glue to the matching positions of the base, the flexible circuit board assembly and related components; (5) Assembly of other parts: Install the wear-resistant sheet and bearing on the middle tube of the base; (6) Install the impeller assembly: Install the impeller assembly on the bearing; (7) Paste the conductive foam on the top surface of the heat sink fins and install the elastic waterproof gasket on the edge of the inner cavity opening of the base; (8) Installing the cover: snapping the top cover onto the inner cavity opening of the base to obtain a miniature waterproof fan.

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