A one-step injection molding process for waterproof encapsulation of TWS earphones

Abstract

The present application discloses a one-time injection molding process for waterproof rubber coating of TWS earphones, which belongs to the field of waterproof earphone design and includes the following steps: the internal components of the earphones are designed into an inner module with a hard plastic shell, which is placed in an outer mold. The gap between the inner module and the outer mold forms an injection molding cavity. The inner module is used as the injection molding core. A plastic shell directly wrapping the inner module is obtained through one-time injection molding, which is an integrated, sealed rubber-coated earphone product with good waterproof performance. The present application solves the sealing problem of the inner module by plugging holes, so that the inner module is isolated from the injection molding cavity and does not leak during injection molding; the present application pressurizes the inner cavity of the inner module during injection molding to reduce the pressure difference on both sides, and sprays heat-insulating coating on the outer wall of the inner module before injection molding to solve the problem of deformation of the inner module under pressure and heat; the present application changes the plastic shell of the existing assembly structure into a new integrated earphone structure, which has a high sealing structure, is drop-resistant and beautiful, and is convenient for design.

Description

Technical Field

[0001] The present application relates to the field of waterproof design of headphones, and in particular to a one-step injection molding process for waterproof encapsulation of TWS headphones. Background Art

[0002] TWS earphones (True Wireless Stereo) are a new type of high-tech earphones based on Bluetooth chip technology. Its working principle is that the mobile phone connects to the main earphones, and then the main earphones quickly connect to the slave earphones wirelessly, realizing true Bluetooth left and right channel wireless separation. When the slave speaker is not connected, the main speaker returns to mono sound quality.

[0003] TWS earphones are developing rapidly, but the plastic shells used to package the components still adopt the injection molding method of traditional earphones, that is, the shell assemblies are injection molded separately with harder materials, and two or more shell assemblies are respectively reserved with connectors and sockets for assembly.

[0004] Since separately injection-molded assembly parts are used, the sealing after assembly is poor and it is easily affected by moisture and dust, which will affect the function and operation of each component, the sound quality and even damage it over time. Moreover, the assembly structure of the shell assembly through the connector and the socket is very weak and cannot withstand drops. The injection-molded shell can easily fall apart and even be damaged.

[0005] Through the above analysis, the inventor team believes that the assembled plastic shell structure can no longer meet the protection requirements of high-quality, high-value TWS headphones, and has attempted to develop a new plastic shell molding process that can be molded in one piece. Summary of the Invention

[0006] The purpose of this application is to solve the shortcomings of the prior art, and thus provide a one-time injection molding process for waterproof encapsulation of TWS earphones.

[0007] This application adopts the following technical solutions:

[0008] A one-time injection molding process for waterproof rubber-coated TWS earphones. The specific design is to install the components inside the earphones into a hard rubber shell to form an inner module of the overall structure. The inner module is placed in an outer mold. The gap between the inner module and the outer mold forms an injection molding cavity. The inner module serves as the injection molding core. Through one-time injection molding, a plastic shell directly wrapping the inner module is obtained, which is a sealed rubber-coated earphone product.

[0009] By adopting the above technical solution, the existing process of separately injecting the plastic shell of the assembly structure is replaced, so as to improve the sealing and drop resistance, and facilitate the design of various integrated appearance designs, so as to design various seamless appearances for the earphones.

[0010] Preferably, the inner module includes a hard plastic shell and components placed in the hard plastic shell, the components including PCBA board, battery, sound unit, speaker, sound output steel mesh, magnet, microphone, FPC line, connector, antenna, LED indicator light, charging IC, lithium battery protection IC, etc. The hard plastic shell includes a lower shell and an upper cover, the lower shell and the upper cover are connected by threads and the connection is treated with sealant, finally forming a relatively closed shell cavity.

[0011] By adopting the above technical solution, the hard plastic shell adopts a split structure, which makes it easy to install the components into the lower shell, and finally screw the cover into an integrated cavity structure to allow the internal gas to flow smoothly, which is convenient for pressurization and ventilation in the subsequent injection molding process.

[0012] Preferably, a microphone hole and a charging hole are provided on the outer wall of the upper cover; an open cylinder is provided at the bottom end of the lower shell and a sound-emitting steel mesh is embedded in it. The sound-emitting steel mesh requires a screen structure for sound output, and an annular groove is formed between the edge of the sound-emitting steel mesh and the inner wall of the cylindrical opening; a speaker hole, a pressure relief hole and a button group are also provided on the outer wall of the lower shell, and the button group is used to adjust the volume.

[0013] By adopting the above technical solution, the microphone hole and the charging hole need to be blocked during injection molding and serve as the positioning point of the upper cover; the annular groove can be used as a positioning point of the lower shell during rubber coating, and the annular groove needs to be sealed after rubber coating; the speaker hole and the pressure relief hole need to be blocked during injection molding, and the button group needs to extend out of the molded plastic shell, so it also needs to be extended into the outer mold during injection molding. During injection molding, the gap between the button group and the lower shell and the outer mold also needs to be sealed and serve as the positioning point of the lower shell.

[0014] Preferably, during injection molding, the lower shell is placed in the lower mold, the upper cover is placed in the upper mold, the lower mold and the upper mold constitute an outer mold, flanges are respectively provided on the outer side of the opening on the top surface of the lower mold and the outer side of the opening on the bottom surface of the upper mold, and the two sets of flanges are connected by fastening bolts.

[0015] By adopting the above technical solution, the outer mold is opened and closed by tightening the fastening bolts.

[0016] Preferably, an injection molding cylinder is provided on the top surface of the upper mold, and a T-shaped stepped hole is provided at the bottom end of the injection molding cylinder. A countersunk hole structure is formed on the top surface of the molded plastic shell. The countersunk hole structure serves as an injection port and is used to nest and adhere a disc with a trademark or to install a switch key after molding. The specific location depends on the distribution of the electronic components of the earphone.

[0017] The outer wall of the upper mold is embedded with an inner module exhaust pipe and a microphone hole ejector pin. One end of the inner module exhaust pipe is inserted into the charging hole and is connected to the inner cavity of the inner module. On the one hand, it blocks the charging hole, and on the other hand, it is used for internal ventilation and air pressure control in the inner module. One end of the microphone hole ejector pin is inserted into the microphone hole to block the hole.

[0018] The outer wall of the lower mold is embedded with a speaker hole plug, a pressure relief hole ejector pin, and a button assembly sleeve. The cross-section of the speaker hole plug is the letter "L" and the letter "R", which are used to identify the left ear or right ear. The outer end face of the speaker hole plug is fastened to the outer wall of the lower mold by a pin. The inner end face of the speaker hole plug is provided with a cylindrical protrusion embedded in the speaker hole, which is used to locate the speaker hole and tightly seal the speaker hole.

[0019] One end of the pressure relief hole ejector pin is inserted into the pressure relief hole to block the hole;

[0020] One end of the key group sleeve is pointed and open and is tightly fitted into the gap between the key group and the lower shell. The outer wall of the key group sleeve is tightly fitted into the gap between the key group and the lower mold to achieve sealing. The outer end surface of the key group sleeve is provided with an outer flange and is fastened to the outer wall of the lower mold by a pin.

[0021] The inner wall of the lower mold is also provided with an inlay embedded in the annular groove, the top surface of the inlay is provided with a cylindrical barrel embedded in the annular groove and the rest of the top surface of the inlay is respectively fitted with the bottom opening surface of the lower shell and the sound outlet steel mesh to form an annular sealing fitting surface, which can block the sound outlet during injection molding. A sieve hole is provided in the center of the top surface of the inlay and extends downward along the edge of the sieve hole to form an inner module air inlet interface. The bottom end of the inner module air inlet interface is connected to an inner module air inlet pipe. The inner module air inlet pipe and the inner module exhaust pipe form the air intake, exhaust and ventilation paths of the inner cavity of the inner module. On the one hand, they are used for ventilation and heat exchange to avoid overheating during the injection molding process. On the other hand, they are used to maintain the air pressure of the inner cavity of the inner module during injection molding to avoid being crushed by the ultra-high injection pressure (8-14Mpa) in the injection molding cavity.

[0022] The injection molding cylinder is also connected to a vacuum tube for ventilating the injection molding cavity and evacuating the cavity before injection molding.

[0023] By adopting the above technical solution, the outer mold is installed with an injection cylinder for liquid inlet, an inner module exhaust pipe for plugging holes, a microphone hole ejector, a speaker hole plug-in block, a pressure relief hole ejector, a button group sleeve and an inlay, and an inner module exhaust pipe, an inner module air inlet pipe and a vacuum tube for ventilation, so that injection molding can proceed smoothly.

[0024] As a general mold design, this application also has a moving mechanism fixed to the top surface of the upper mold.

[0025] By adopting the above technical solution, it is used for opening and closing the mold or unloading after injection molding.

[0026] As a general mold design, this application also provides core ejection mechanisms on both the upper mold and the lower mold.

[0027] By adopting the above technical solution, it is used for ejection injection molding.

[0028] As a general mold design, and in order to adapt to the temperature required for injection molding and curing, the present application also embeds multiple sets of heating plates near the inner wall of the cavity in the upper mold and the lower mold.

[0029] By adopting the above technical solution, the injection molding cavity can be kept warm, heated or thermally vulcanized and cured.

[0030] Considering waterproofing, drop resistance, and the soft rubber's skin-friendly feel, and aiming for suitability in various environments, this application selects soft silicone and hard PVC materials for the plastic housing. Silicone is molded using a mold-in-beer process, ensuring that the microphone and tuning holes are electrically connected to the plastic housing's air intake without affecting functionality. PVC is molded using a casting process, ensuring that the microphone and tuning holes are electrically connected to the plastic housing's air intake without affecting functionality.

[0031] In summary, this application includes at least one of the following beneficial technical effects:

[0032] 1. This application adopts mold design. First, the internal components of the earphones are installed into the lower shell, and screwed together with the upper cover to form an inner module with a hard plastic shell. The inner module is placed in an outer mold as an injection molding core. The gap between the inner module and the outer mold forms an injection molding cavity. A plastic shell that directly wraps the inner module is obtained through one-time injection molding, thereby converting the plastic shell of the existing assembly structure into a new integrated earphone structure. Its sealing structure is high, drop-resistant and beautiful, which is conducive to design.

[0033] 2. In order to realize the above injection molding process, the sealing problem of the inner module must be solved first. This application uses the outer mold to plug the inner module exhaust pipe, microphone hole ejector pin, speaker hole plug-in block, pressure relief hole ejector pin, button group sleeve and inlay, and respectively seal the charging hole, microphone hole, speaker hole, pressure relief hole, button group and the annular groove at the sound output steel mesh of the inner module, so that the inner module and the injection molding cavity are completely isolated and leak-proof during injection molding, maintaining good sealing.

[0034] 3. In order to realize the above injection molding process, the second problem of pressure and thermal deformation of the inner module must be solved. During injection molding, the present application simultaneously pressurizes the inner module cavity through the inner module air inlet pipe to make the pressure difference on both sides of the inner module smaller, and also ensures that the internal temperature is low. In addition, the outer wall of the inner module is sprayed with thermal insulation coating. The thermal insulation coating can be selected from high-temperature resistant paint (such as silicone high-temperature resistant paint with a temperature resistance of 200-400°C) doped with 10-20% aerogel particles, 5-10% cavitation glass powder and 3-5% viscosity enhancer of the total paint mass, so as to appropriately increase the heat resistance temperature of the inner module and protect the stability of the components during injection molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flow chart of a one-step injection molding process for waterproof encapsulation of TWS earphones used in this application;

[0036] Figure 2 This is a schematic structural diagram of an injection molding cavity and a mold used in the injection molding process of Example 1 of the present application;

[0037] Figure 3 This application Figure 2 A magnified view of point A;

[0038] Figure 4 This application Figure 2 Enlarged view of point B;

[0039] Figure 5 This application Figure 2 Enlarged view of point C;

[0040] Figure 6 This application Figure 2 Enlarged view of point D;

[0041] Figure 7 This application Figure 2 Enlarged view of point E;

[0042] Figure 8 This is a schematic structural diagram of an injection molding cavity and a mold used in the injection molding process of Example 2 of the present application;

[0043] Figure 9 This application Figure 8 Enlarged view of point F;

[0044] Figure 10 This application Figure 8 Enlarged view of point G.

[0045] Explanation of the accompanying reference numerals: 1. Hard plastic shell; 10. Assembly; 11. Lower shell; 12. Upper cover; 13. Microphone hole; 14. Charging hole; 15. Sound outlet steel mesh; 16. Annular groove; 17. Speaker hole; 18. Pressure relief hole; 19. Button group; 2. Outer mold; 20. Injection molding cavity; 21. Lower mold; 22. Upper mold; 23. Flange; 24. Fastening bolt; 25. Injection molding cylinder; 26. Inner mold exhaust pipe; 27. Microphone hole ejector pin; 28. Speaker hole plug-in block; 29. Pressure relief hole ejector pin; 30. Button group sleeve; 31. Inlay; 32. Sieve hole; 33. Inner mold air inlet interface; 34. Inner mold air inlet pipe; 35. Vacuum tube; 40. Plastic shell. DETAILED DESCRIPTION

[0046] The following is combined with Figure 1-10 This application is described in further detail.

[0047] Example 1:

[0048] Reference Figure 1A one-time injection molding process for waterproof rubber-coated TWS earphones. The component 10 is pre-installed in the lower shell 11, then the cover is screwed and sealed (glue is applied if necessary). After fixing, it serves as the injection molding inner core and forms an injection molding cavity 20 with the outer mold 2. After one-time injection molding, an earphone product that can be shipped is obtained. Its plastic shell is made of silicone, which is a soft material. The ear-in-ear part in the lower mold 21 is injected with an outward-turned mold. The obtained plastic shell 40 is also in an outward-turned shape and can be turned into an in-ear shape before shipping.

[0049] Reference Figure 2-7 , 9 and 10, the process comprises the following specific steps:

[0050] 1) Inner module installation: Install each component into the lower housing 11 in sequence, fill the threaded opening at the top of the lower housing 11 with sealant and tighten the upper cover 12;

[0051] 2) Coating and sealing: Spray heat-insulating coating on the hard plastic shell of the inner module. The hard plastic shell is preferably made of polyetherimide plastic (PEI) with a high temperature resistance of more than 170°C. The heat-insulating coating is used to isolate the temperature difference of 15-20°C below 150°C, which plays the role of isolating and protecting the hard plastic shell. The spraying can be carried out on the upper mold 22 and the lower mold 21. Specifically, the upper mold 22 and the upper cover 12 are preferably fastened through the inner module exhaust pipe 26 and the microphone hole ejector pin 27, and a support is provided at the bottom of the lower shell 11. , fill the sealing protection ring in the gap between the upper mold 22 and the upper cover 12, spray the lower part of the hard plastic shell, and after heat drying, remove the inner module exhaust pipe 26 and microphone hole ejector pin 27; install the lower shell 11 into the lower mold 21 through the speaker hole plug 28, pressure relief hole ejector pin 29, button group sleeve 30 and inlay 31, and fill the sealing protection ring in the gap between the lower shell 11 and the lower mold 21, spray the upper part of the hard plastic shell, and heat dry to complete the spraying;

[0052] 3) Inner module fixation and sealing test: Use the inner module exhaust pipe 26, microphone hole ejector pin 27, speaker hole insert 28, pressure relief hole ejector pin 29, button assembly sleeve 30, and inlay 31 to complete the hole blocking and position the inner module and outer mold 2. Test the sealing of the inner module internal cavity through the inner module air intake pipe 34 and inner module exhaust pipe 26. Test the sealing of the injection cavity 20 through the vacuum tube 35.

[0053] 4) Air guide, vacuum, temperature control, and injection molding: The injection molding cavity 20 is ventilated and vacuumed to below 0.01Mpa. Liquid silicone rubber with a temperature below 90°C is injected at 8-14Mpa. Room-temperature air is quickly filled in through the inner mold inlet pipe 34. During the injection molding process, the internal cavity pressure of the inner mold is continuously controlled at 10±2Mpa to maintain a small pressure difference on both sides of the hard plastic shell to avoid stress damage. The liquid silicone rubber model is LSR9970A. The cavity is heated to 110-130°C and hot vulcanized for 5-10 minutes.

[0054] 5) Demolding and Unloading: Remove the speaker hole insert 28, pressure relief hole ejector pin 29, and button assembly sleeve 30. Open the mold, eject the lower housing 11, lift the upper mold 22, move it to the unloading area, and eject the plastic shell 40. This results in a one-piece, waterproof, silicone-shell, encapsulated earphone product. Temperature testing showed that during the injection molding time (including thermal curing) of Example 1, the surface temperature of each electronic component was 35-45°C, demonstrating that the thermal insulation coating, the housing, and the air inside it provide adequate thermal insulation protection.

[0055] Example 2:

[0056] Reference Figure 3-10 A one-step injection molding process for waterproof rubberized TWS earphones is described. The plastic shell 40 is made of PVC, a hard material. The in-ear portion of the lower mold 21 is directly molded with an in-ear mold. The process includes the following specific steps:

[0057] 1) Inner module installation: Install each component into the lower housing 11 in sequence, fill the threaded opening at the top of the lower housing 11 with sealant and tighten the upper cover 12;

[0058] 2) Coating and sealing: Spray heat-insulating coating on the hard plastic shell of the inner module. The hard plastic shell is preferably made of polyethersulfone plastic (PES) with a high temperature resistance of about 200°C. The heat-insulating coating is used to isolate the temperature difference of 20-30°C below 200°C, and plays the role of isolating and protecting the hard plastic shell. The spraying can be carried out in the upper mold 22 and the lower mold 21. Specifically, the upper mold 22 and the upper cover 12 are preferably fastened through the inner module exhaust pipe 26 and the microphone hole ejector pin 27, and a support is provided at the bottom of the lower shell 11. Fill the gap between the upper mold 22 and the upper cover 12 with a sealing ring, spray the lower part of the hard plastic shell, and after heat drying, remove the inner mold exhaust pipe 26 and microphone hole ejector pin 27; install the lower shell 11 into the lower mold 21 through the speaker hole plug 28, pressure relief hole ejector pin 29, button group sleeve 30 and inlay 31, and fill the gap between the lower shell 11 and the lower mold 21 with a sealing ring, spray the upper part of the hard plastic shell, and heat dry to complete the spraying;

[0059] 3) Inner module fixation and sealing test: Use the inner module exhaust pipe 26, microphone hole ejector pin 27, speaker hole insert 28, pressure relief hole ejector pin 29, button assembly sleeve 30, and inlay 31 to complete the hole blocking and position the inner module and outer mold 2. Test the sealing of the inner module internal cavity through the inner module air intake pipe 34 and inner module exhaust pipe 26. Test the sealing of the injection cavity 20 through the vacuum tube 35.

[0060] 4) Air conduction, vacuum, temperature control, and injection molding: The injection molding cavity 20 is ventilated and vacuumed to below 0.01 MPa. Molten PVC at 180-190°C is injected at 8-14 MPa. The cavity temperature is controlled at 50-60°C. Room-temperature air is quickly filled in through the inner mold group air inlet pipe 34. During the injection molding process, the internal cavity pressure of the inner mold group is continuously controlled at 10±2 MPa to maintain a small pressure difference on both sides of the hard plastic shell to avoid stress damage.

[0061] 5) Demolding and Unloading: After cooling and solidification, remove the speaker hole insert 28, pressure relief hole ejector pin 29, and button assembly sleeve 30. Open the mold and eject the lower housing 11. Lift the upper mold 22 and move it to the unloading area to eject the plastic housing 40. This results in an integrated, waterproof, silicone-shell sealed earphone product. To enhance in-ear comfort, the outer wall of the plastic housing 40 can be sprayed with a soft silicone coating or covered with a leather cover. Temperature testing showed that during the injection molding time (including thermal curing) of Example 1, the surface temperature of each electronic component was 50-65°C, indicating that the thermal insulation coating, the housing, and the air inside it provided adequate thermal insulation protection.

[0062] Example 3:

[0063] On the basis of Example 2, the molded PVC plastic shell 40 is used as the inner core, and a mold larger than the outer mold 2 used in step 2) is set as a new mold. A new injection molding cavity is formed between the inner core and the new mold. Steps 3) to 5) of Example 1 are repeated to inject a thin silicone sleeve, thereby obtaining a double-layer shell structure in which the PVC hard plastic shell 40 is encapsulated by a layer of soft silicone.

[0064] It should be noted that the two methods of Examples 1 and 2 are mainly considered from the perspectives of waterproofness, drop resistance, and the comfort of soft rubber contacting the skin, with the purpose of being suitable for use in various environments, but this application is not limited to these two materials.

[0065] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A one-step injection molding process for waterproof encapsulation of TWS earphones, characterized by: The following steps are involved: The components (10) of the inner part of the earphone are installed in the hard plastic shell (1) to form an inner module of the overall structure, and the inner module is placed in an outer mold (2). The gap between the inner module and the outer mold forms an injection molding cavity (20). The inner module serves as the injection molding inner core. A plastic shell (40) directly wrapping the inner module is obtained by one-time injection molding, which is a sealed rubber-coated earphone product; The hard plastic shell comprises a lower shell (11) and an upper cover (12), wherein the lower shell (11) and the upper cover (12) are connected by threads, and the connection is sealed by glue; During injection molding, the lower shell (11) is placed in the lower mold (21), and the upper cover (12) is placed in the upper mold (22). The lower mold (21) and the upper mold (22) constitute an outer mold (2). Flanges (23) are respectively provided on the outer side of the top opening of the lower mold (21) and the outer side of the bottom opening of the upper mold (22), and the two sets of flanges (23) are connected by fastening bolts (24); The top surface of the upper mold (22) is provided with an injection molding cylinder (25), and the bottom end opening of the injection molding cylinder (25) is provided with a T-shaped step hole; The outer wall of the upper mold (22) is embedded with an inner mold exhaust pipe (26) and a microphone hole ejector pin (27), and one end of the inner mold exhaust pipe (26) is inserted into the charging hole (14) and is in communication with the inner cavity of the inner mold; The outer wall of the lower mold (21) is embedded with a speaker hole plug (28), a pressure relief hole ejector pin (29) and a key group sleeve (30); the outer end surface of the speaker hole plug (28) is fastened to the outer wall of the lower mold (21) by a pin; the inner end surface of the speaker hole plug (28) is provided with a cylindrical convex body embedded in the speaker hole (17) for positioning the speaker hole (17) and tightly sealing the speaker hole (17); One end of the pressure relief hole ejector pin (29) is inserted into the pressure relief hole (18); One end of the button group sleeve (30) is pointed and open and is tightly fitted in the gap between the button group (19) and the lower shell (11). The outer wall of the button group sleeve (30) is tightly fitted in the gap between the button group (19) and the lower mold (21) to achieve sealing. The outer end surface of the button group sleeve (30) is provided with an outer flange and is fastened to the outer wall of the lower mold (21) by a pin. The inner wall of the lower mold (21) is further provided with an inlay (31) embedded in the annular groove (16), the top surface of the inlay (31) is provided with a cylindrical body embedded in the annular groove (16), and the remaining parts of the top surface of the inlay (31) are respectively fitted with the bottom opening surface of the lower shell (11) and the sound outlet steel mesh (15) to form an annular sealing fitting surface, a sieve hole (32) is opened in the center of the top surface of the inlay (31) and extends downward along the edge of the sieve hole (32) to form an inner module air inlet interface (33), and the bottom end of the inner module air inlet interface (33) is connected to the inner module air inlet pipe (34); The injection molding cylinder (25) is also connected to a vacuum tube (35).

2. A one-step injection molding process for waterproof rubber encapsulation of TWS earphones according to claim 1, characterized in that: The outer wall of the upper cover (12) is provided with a microphone hole (13) and a charging hole (14); the bottom end of the lower shell (11) is provided with an open cylinder and a sound-emitting steel mesh (15) is embedded therein, and the edge of the sound-emitting steel mesh (15) and the inner wall of the cylindrical opening form an annular groove (16); the outer wall of the lower shell (11) is also provided with a speaker hole (17), a pressure relief hole (18) and a button group (19).

3. A one-step injection molding process for waterproof rubber encapsulation of TWS earphones according to claim 1, characterized in that: The top surface of the upper mold (22) is fixedly connected with a moving mechanism.

4. A one-step injection molding process for waterproof rubber encapsulation of TWS earphones according to claim 1, characterized in that: The upper mold (22) and the lower mold (21) are both provided with a core ejection mechanism.

5. A one-step injection molding process for waterproof rubber encapsulation of TWS earphones according to claim 1, characterized in that: The upper mold (22) and the lower mold (21) are embedded with multiple groups of heating plates near the inner wall of the cavity.

6. A one-step injection molding process for waterproof rubber encapsulation of TWS earphones according to claim 1, characterized in that: The plastic shell (40) is made of silicone, which is a soft material. The ear-entry portion in the lower mold (21) is injection-molded using an outward-turned mold, so that the obtained plastic shell (40) is also in an outward-turned shape. It can be turned into an ear-entry shape before leaving the factory. The process includes the following specific steps: 1) Inner module installation: install each component into the lower housing (11) in sequence, fill the threaded opening at the top of the lower housing (11) with sealant and tighten the upper cover (12); 2) Coating and sealing: Spray heat-insulating coating on the inner module hard plastic shell (1). The hard plastic shell (1) is a hard plastic that is resistant to high temperatures of 150°C. The heat-insulating coating is used to isolate the temperature difference of 15-20°C below 150°C, and plays the role of isolating and protecting the hard plastic shell. The spraying is carried out in the upper mold (22) and the lower mold (21). Specifically, the upper mold (22) and the upper cover (12) are fastened by the inner module exhaust pipe (26) and the miking pin (27), and a support is provided at the bottom of the lower shell (11). Fill the sealing protection ring in the mouth gap of the body (12), spray the lower part of the hard plastic shell (1), and after heat drying, remove the inner module exhaust pipe (26) and the microphone hole ejector pin (27); install the lower shell (11) in the lower mold (21) through the speaker hole plug (28), the pressure relief hole ejector pin (29), the button group sleeve (30) and the inlay (31), and fill the sealing protection ring in the mouth gap of the lower shell (11) and the lower mold (21), spray the upper part of the hard plastic shell (1), and heat dry to complete the spraying; 3) Inner module fixation and sealing test: The inner module and outer mold (2) are blocked and positioned by using the inner module exhaust pipe (26), microphone hole ejector pin (27), speaker hole plug (28), pressure relief hole ejector pin (29), key group sleeve (30) and inlay (31). The sealing of the inner module cavity is tested by using the inner module air inlet pipe (34) and the inner module exhaust pipe (26). The sealing of the injection molding cavity is tested by using the vacuum tube (35); 4) Air guide, vacuum, temperature control, injection molding: The injection molding cavity (20) is ventilated and vacuumed to below 0.01Mpa, and liquid silicone below 90°C is injected at 8-14Mpa. The air at room temperature is quickly filled in through the inner mold inlet pipe (34). During the injection molding process, the air pressure inside the inner mold cavity is continuously controlled to 10±2Mpa, and the pressure difference on both sides of the hard plastic shell (1) is kept small to avoid stress damage. The liquid silicone model is LSR9970A. The cavity is heated to 110-130°C and hot vulcanized for 5-10 minutes. 5) Demolding and unloading: Remove the speaker hole plug (28), the pressure relief hole ejector pin (29) and the button group sleeve (30), open the mold to eject the lower shell (11), lift the upper mold (22), move it to the unloading area, and eject the plastic shell (40), thus obtaining an integrated silicone shell sealed rubber-coated earphone product with better waterproof performance.

7. A one-step injection molding process for waterproof rubber encapsulation of TWS earphones according to claim 1, characterized in that: The plastic shell (40) is made of PVC, which is a hard material. The ear-entry portion in the lower mold (21) is directly molded with an ear-entry mold. The process includes the following specific steps: 1) Inner module installation: install each component into the lower housing (11) in sequence, fill the threaded opening at the top of the lower housing (11) with sealant and tighten the upper cover (12); 2) Coating and sealing: Spray heat-insulating coating on the inner module hard plastic shell (1). The hard plastic shell (1) is a hard plastic that is resistant to high temperatures of 200°C. The heat-insulating coating is used to isolate the temperature difference of 20-30°C below 200°C, and plays the role of isolating and protecting the hard plastic shell. The spraying is carried out in the upper mold (22) and the lower mold (21). Specifically, the upper mold (22) and the upper cover (12) are fastened by the inner module exhaust pipe (26) and the miking pin (27), and a support is provided at the bottom of the lower shell (11). Fill the sealing protection ring in the mouth gap of the body (12), spray the lower part of the hard plastic shell (1), and after heat drying, remove the inner module exhaust pipe (26) and the microphone hole ejector pin (27); install the lower shell (11) in the lower mold (21) through the speaker hole plug (28), the pressure relief hole ejector pin (29), the button group sleeve (30) and the inlay (31), and fill the sealing protection ring in the mouth gap of the lower shell (11) and the lower mold (21), spray the upper part of the hard plastic shell (1), and heat dry to complete the spraying; 3) Inner module fixation and sealing test: The inner module and outer mold (2) are blocked and positioned by using the inner module exhaust pipe (26), microphone hole ejector pin (27), speaker hole plug (28), pressure relief hole ejector pin (29), key group sleeve (30) and inlay (31). The sealing of the inner module cavity is tested by using the inner module air inlet pipe (34) and the inner module exhaust pipe (26). The sealing of the injection molding cavity (20) is tested by using the vacuum tube (35); 4) Air conduction, vacuum, temperature control, and injection molding: The injection molding cavity is ventilated and vacuumed to below 0.01 MPa, and molten PVC at 180-190°C is injected at 8-14 MPa. The cavity temperature is controlled to 50-60°C, and room temperature air is quickly filled in through the inner mold group air inlet pipe (34). During the injection molding process, the air pressure inside the inner mold group is continuously controlled to 10±2 MPa, and the pressure difference on both sides of the hard plastic shell (1) is kept small to avoid stress damage; 5) Demolding and unloading: After cooling and solidification, remove the speaker hole plug (28), the pressure relief hole ejector pin (29) and the button group sleeve (30), open the mold and eject the lower shell (11), lift the upper mold (22), move it to the unloading area, and eject the plastic shell (40), thus obtaining an integrated silicone shell sealed rubber-coated earphone product with good waterproof performance.

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