Waterproof PCB (Printed Circuit Board)

Abstract

The invention discloses a waterproof PCB (Printed Circuit Board), and belongs to the technical field of PCBs. Comprising a PCB body, and components are distributed and welded on the PCB body. The components comprise a large-size component which exceeds the height of the top surface of the PCB body by 6mm after being welded and a small-size component which does not exceed the height of 6mm after being welded on the top surface of the PCB body; the structure also comprises a sealing seat, a potting colloid and a waterproof coating. The sealing seat is fixed at the periphery of the large-size component. The large-size component is embedded into the inner side of the sealing seat and is in press fit with the blocking edge, and the large-size component is welded to the PCB body; the PCB body is provided with a glue injection through hole in the inner side of the sealing seat; the pouring sealant is poured into a sealed cavity formed by the large-size component, the sealing base, the blocking edge and the PCB body through the sealant injection through hole. According to the waterproof PCB, the PCB body has a waterproof effect, and meanwhile, the external waterproof unit is adopted to package the PCB body, so that external water vapor can be prevented from approaching the PCB body, and the waterproof effect of the PCB body is ensured.

Description

Technical Field

[0001] The invention specifically relates to a PCB waterproof circuit board, and belongs to the technical field of PCB circuit boards. Background Art

[0002] In the prior art, the waterproof technology of circuit boards mainly includes structural waterproofing, potting waterproofing and waterproof and moisture-proof coatings. Among them, the waterproof and moisture-proof coating is the optimal solution for current circuit board waterproofing technology, which can meet the waterproofing needs in almost any situation. However, the cost of large-area coating is too high, and the potting waterproofing adopts epoxy resin potting glue, which is used for the potting of electronic product modules. There are problems such as large potting volume and poor maintenance. Therefore, at this stage, the most common circuit board waterproofing method is structural waterproofing. However, in actual applications, penetrating water mist will be formed in the waterproof structure, which is easy to cause erosion to the circuit board. For this reason, China Patent Publication No.: CN117163475A discloses a CBP waterproof circuit board. Under normal circumstances, since the air flow can be maintained in the waterproof box, it is not easy to generate water vapor and water mist. , it is not easy to cause corrosion to the CBP circuit board, but the structure only seals the holding plate and the CBP circuit board through buoyancy, and the sealing effect is general; in addition, the existing PCB circuit board needs to arrange components of various sizes according to the circuit function requirements, such as surface mount components and plug-in components. For plug-in components such as heat sinks, transformers, inductors and rectifiers, the sizes are relatively large. If the waterproof coating is directly applied to the plug-in components, the waterproof coating consumes a lot of money and is blocked by the components, and the pins cannot be completely coated, thereby failing to achieve a waterproof effect; in addition, for some sensors that require sensitive sensing, such as light sensors, thermal sensors and humidity sensors, it is necessary to protect the sensor detection surface; if the waterproof coating is directly applied to the detection surface, it is easy to affect the sensitivity of the sensor. Summary of the invention

[0003] In order to solve the above problems, the present invention proposes a PCB waterproof circuit board. The PCB board body itself has a waterproof effect. At the same time, an external waterproof unit is used to encapsulate the PCB board body, which can prevent external water vapor from approaching the PCB board body and ensure the waterproof effect of the PCB board body.

[0004] The PCB waterproof circuit board of the present invention comprises a PCB body, on which components are arranged and welded; the components comprise large-sized components whose height exceeds 6 mm of the top surface of the PCB body after welding and small-sized components whose height does not exceed 6 mm of the top surface of the PCB body after welding; and further comprises: A sealing seat, the sealing seat is fixed to the periphery of the large-sized components; the inner side of the sealing seat is a cavity with hollow ends, the inner side of the sealing seat is integrally formed with a retaining edge, the large-sized components are embedded in the inner side of the sealing seat and pressed with the retaining edge, and the large-sized components are welded to the PCB board; the PCB board is provided with a glue injection through hole on the inner side of the sealing seat; A potting colloid is poured into a sealed cavity formed by the large-sized components, the sealing seat, the retaining edge and the PCB body through the injection hole; the potting colloid covers the bottom surface of the large-sized components; The waterproof coating comprises a first waterproof coating and a second waterproof coating; after the small-sized components are welded to the PCB body, the first waterproof coating is coated on the top surface of the PCB body and the outside of the small-sized components; after all the components are welded, the second waterproof coating is coated on the bottom surface of the PCB body.

[0005] When processing a PCB waterproof circuit board, firstly, the PCB wiring is performed according to the circuit schematic diagram, then, the PCB body is processed, and the PCB body is punched and coated with a vacuum varnish coating, then, the small-sized components are welded to the PCB body, and after welding, the first waterproof coating is coated on the top surface of the PCB body and the outside of the small-sized components, and the PCB body and the small-sized components are waterproofly protected by the first waterproof coating; then, the sealing seat is installed, and the sealing seat is fixed to the periphery of the installation position of the large-sized components. After the sealing seat and the top surface of the PCB body are installed, then, the large-sized components are welded to the PCB body, and a circuit test is performed; after the test passes, the encapsulation colloid operation is performed, and the encapsulation head of the encapsulation equipment is aligned with the encapsulation through hole, and then the encapsulation colloid is injected into the sealed cavity formed by the large-sized components, the sealing seat, the retaining edge and the PCB body, and the large-sized components are filled and coated with the encapsulation colloid, so that the lower part of the device body and the pins of the large-sized components are waterproofly protected, so that the PCB waterproof circuit board has a waterproof effect.

[0006] Furthermore, the waterproof coating is a nano waterproof coating; vacuum varnish coatings are provided on both sides of the PCB body; the vacuum varnish coatings can be used to apply glue to both sides of the PCB body; and the circuit traces on the PCB body are protected.

[0007] Furthermore, the sealing seat is fixed to the PCB body by bonding or welding; when welding, it is necessary to leave the pin mounting holes of the sealing seat in advance when wiring the PCB body, and finally, the sealing seat is directly welded to the PCB body as a component; when bonding is adopted, adhesive is directly applied to the bottom of the sealing seat, and finally, the sealing seat is bonded to the PCB body.

[0008] Furthermore, when the pins of the large-size components are located outside the component body, the blocking edge is a horizontal bar, and the potting colloid is poured in from the top inside the sealing seat and covers the pins of the large-size components; the bottom of the large-size components is limited by the blocking edge, so that the pins of the large-size components can be maintained at a set height, allowing the potting colloid to smoothly enter and fill the inside of the sealing seat.

[0009] Further, the PCB body is mounted on an external waterproof unit, and the external waterproof unit comprises an upper shell and a lower shell, and a plurality of ear seats are integrally formed on one side of the upper shell and the lower shell near each other; the ear seats are fastened by bolts and nuts, and a sealing ring is arranged between the upper shell and the lower shell; an inner ring seat is integrally formed on the inner side of the upper shell; a ring groove is provided on the inner ring seat, a plurality of blind holes are provided on the inner edge of the top surface of the PCB body, and a pressure ring is bonded and fixed on the inner edge of the top surface of the PCB body; an embedded column engaged with the blind hole is provided on the pressure ring; the pressure ring is embedded in the inner side of the ring groove; an epoxy resin sealing layer is provided between the outside of the PCB body and the inside of the upper shell; a cable waterproof assembly is arranged at the end of the upper shell; The cable passes through the inner side of the cable waterproof assembly, and the cable is electrically connected to the PCB board body; during installation, first apply glue to the inner edge of the pressure ring and the top surface of the PCB board body, then lead the cable on the PCB board body out of the cable waterproof assembly; then, align the embedded column of the pressure ring with the blind hole of the PCB board body, so that the PCB board body and the pressure ring fitting surface form a sealing surface; then, align the pressure ring with the ring groove of the inner ring seat, and finally, apply and cure an epoxy resin sealing layer between the outside of the PCB board body and the inside of the upper shell body; thereby forming a sealed cavity between the inner side of the upper shell body and the PCB board body; finally, align the upper shell body and the lower shell body, and embed the sealing ring, and finally, fasten the ear seats on the upper shell body and the lower shell body into one by bolts and nuts.

[0010] Furthermore, the cable waterproofing assembly includes a waterproof connector that is embedded and fixed at the end of the upper shell; the upper shell is integrally formed with a screw sleeve on the outside of the waterproof connector, a head is screwed on the screw sleeve, and the cable movably passes through the head; a potting colloid is arranged in the space formed by the screw sleeve and the head; during operation, the PCB board, cable and waterproof connector are connected first, then the cable is passed through the head, and the potting colloid is injected into the screw sleeve through the injection hole on the screw sleeve; thereby, the connection between the waterproof connector and the cable can be waterproofed.

[0011] Furthermore, a hygroscopic fiber felt is bonded to the inner surface of the upper shell; an outer convex bin is integrally formed on the outer top surface of the upper shell; an exhaust pipe is embedded and fixed to the inner surface of the hygroscopic fiber felt of the upper shell; the exhaust pipe is connected to the outside of the outer convex bin, and two exhaust valves connected in series are arranged on the exhaust pipe, and the exhaust valves are connected to the PCB board; a pressure transmitter and a humidity transmitter are arranged on the PCB board; an inflation component is arranged on the upper shell; when the humidity transmitter detects that the water vapor inside the external waterproof unit reaches the set value, the external exhaust valve is opened first, so that the pipe section from the outside of the exhaust pipe to the output end of the closed exhaust valve is in an atmospheric pressure state, and then Close the external exhaust valve and open the internal exhaust valve. Since the pressure of the external waterproof unit is greater than the atmospheric pressure, the moisture inside the external waterproof unit can be discharged into the exhaust pipe through the hygroscopic fiber felt. After the exhaust is completed, close the exhaust valve; the hygroscopic fiber felt continues to absorb moisture. During exhaust, the moisture on the hygroscopic fiber felt can be carried away by the airflow, thereby maintaining the hygroscopicity of the hygroscopic fiber felt; when the pressure transmitter detects that the pressure is lower than the set value, the PCB board sends a signal that inflation is required, and the inflation component inflates the inside of the external waterproof unit, and uses the pressure difference between the inside and outside of the external waterproof unit to prevent water vapor from entering the external waterproof unit.

[0012] Furthermore, the inflation component is an inflation nozzle; when in operation, pressurized air is filled into the external waterproof unit through the inflation nozzle; so that the internal air pressure of the external waterproof unit reaches a set pressure.

[0013] Furthermore, the inflation component includes a pump group fixed on the inner side of the upper shell, and the input end of the pump group is connected to the output end of the exhaust pipe; the output end of the exhaust pipe is connected in parallel with two one-way valves, and the opening directions of the one-way valves are opposite; the output end of the pump group is in a hollow state; the pump group is connected to the PCB board; when it is necessary to fill the internal part of the external waterproof unit with pressurized air, the pump group is turned on, and the air outside the external waterproof unit is filled into the exhaust pipe through a one-way valve, and then filled into the internal part of the external waterproof unit through the pump group; when the internal part of the external waterproof unit reaches a set pressure value, the pump group is stopped; when the pump group inflates the external waterproof unit, the pump group outlet is directly opposite to the humidity transmitter. When the pump group is turned on, the humidity transmitter performs humidity sampling in real time. When the humidity exceeds the set value, the inflation is stopped and the inflation is postponed until a suitable inflation environment is detected for inflation. When multiple humidity samplings fail, a manual triggering inflation instruction is issued.

[0014] Compared with the prior art, the PCB waterproof circuit board of the present invention can protect the wiring of the PCB board body by loading the vacuum varnish coating on the PCB board body itself, and then, the two sides of the PCB board body, the outer surfaces of the patch components and the small-sized components are waterproofed by the nano waterproof coating, which can save the nano waterproof coating and avoid the coating dead angle of the nano waterproof coating caused by the shielding of the large-sized components; ensure the waterproof effect, and finally, by adding a sealing seat to the outside of the large-sized components and pouring the potting colloid, the surroundings of the pins of the large-sized components and the lower part of the device body of the large-sized components are waterproofed; the devices on the PCB waterproof circuit board can be protected from the erosion effect of water fog; at the same time, the PCB board body itself has a waterproof effect, and at the same time, the PCB board body is encapsulated by an external waterproof unit, which can isolate the flow water from approaching the PCB board body; when water vapor is generated inside the external waterproof unit, the water vapor can be discharged in time; thereby the PCB board body is always kept dry. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention is a schematic diagram of a PCB body coated with a first waterproof coating structure after welding small-sized components.

[0016] Figure 2 It is a schematic diagram of the PCB body, small-sized components and sealing seat installation structure of the present invention.

[0017] Figure 3 It is a schematic diagram of the structure of coating a second waterproof coating on a PCB body of the present invention.

[0018] Figure 4 It is a schematic diagram of the installation structure of the PCB body, large-sized components with external pins and potting colloid of the present invention.

[0019] Figure 5 It is a schematic diagram of the installation structure of the PCB body, large-sized components with inner pins and potting colloid of the present invention.

[0020] Figure 6 It is a schematic diagram of the installation structure of the PCB board, the voltage regulator tube and the potting colloid of the present invention.

[0021] Figure 7 It is a schematic diagram of the installation structure of the PCB board, sensor and potting colloid of the present invention.

[0022] Figure 8 It is a schematic diagram of the structure of the external waterproof unit and the PCB board body before installation of the present invention.

[0023] Fig. 9 It is a schematic diagram of the structure after the external waterproof unit and PCB board body of the present invention are installed.

[0024] Fig.10This is a schematic diagram of the structure of the external waterproof unit, the inflation component and the PCB board before installation of the present invention.

[0025] Fig.11 For the present invention Fig.10 Schematic diagram of the local enlarged structure at point A in the middle.

[0026] Fig.12 This is a schematic diagram of the structure of the external waterproof unit, moisture-absorbing fiber felt and PCB board body of the present invention before installation.

[0027] Fig.13 It is a schematic diagram of the structure of the external waterproof unit of the present invention with the top surface facing downward.

[0028] Fig.14 It is a schematic diagram of the structure in which the top surface of the external waterproof unit of the present invention faces upward.

[0029] Figure numerals: 1. PCB board, 2. large-size components, 3. small-size components, 4. sealing seat, 5. retaining edge, 6. glue injection through hole, 7. potting colloid, 8. first waterproof coating, 9. second waterproof coating, 10. upper shell, 11. lower shell, 12. ear seat, 13. inner ring seat, 14. ring groove, 15. pressure ring, 16. embedded column, 17. cable, 18. waterproof joint, 19. screw sleeve, 20. head, 21. moisture-absorbing fiber felt, 22. external convex bin, 23. exhaust pipe, 24. one-way valve. DETAILED DESCRIPTION

[0030] Example: like Figures 1 to 14 The PCB waterproof circuit board shown includes a PCB body 1, on which components are arranged and welded; the components include large-sized components 2 whose height exceeds 6 mm from the top surface of the PCB body 1 after welding and small-sized components 3 whose height does not exceed 6 mm from the top surface of the PCB body 1 after welding; and also includes: Sealing seat 4, the sealing seat 4 is fixed to the periphery of the large-sized component 2; the inner side of the sealing seat 4 is a cavity with two hollow ends, the inner side of the sealing seat 4 is integrally formed with a retaining edge 5, the large-sized component 2 is embedded in the inner side of the sealing seat 4 and pressed with the retaining edge 5, and the large-sized component 2 is welded to the PCB board body 1; the PCB board body 1 is provided with a glue injection through hole 6 on the inner side of the sealing seat 4; A potting colloid 7 is poured into the sealing cavity formed by the large-sized component 2, the sealing seat 4, the retaining edge 5 and the PCB body 1 through the injection hole 6; the potting colloid 7 covers the bottom surface of the large-sized component 2; A waterproof coating, the waterproof coating includes a first waterproof coating 8 and a second waterproof coating 9; after the small-sized components 3 are welded to the PCB body 1, the first waterproof coating 8 is coated on the top surface of the PCB body 1 and the outside of the small-sized components 3; after all the components are welded, the second waterproof coating 9 is coated on the bottom surface of the PCB body 1.

[0031] When processing a PCB waterproof circuit board, first perform PCB wiring according to the circuit schematic diagram, then process the PCB body 1, punch holes in the PCB body 1, and apply a vacuum varnish coating, then weld the small-sized components 3 to the PCB body 1, and after welding, coat the top surface of the PCB body 1 and the outside of the small-sized components 3 with a first waterproof coating 8, and use the first waterproof coating 8 to provide waterproof protection for the PCB body 1 and the small-sized components 3; then install the sealing seat 4, and fix the sealing seat 4 to the periphery of the installation position of the large-sized component 2, and after the sealing seat 4 and the top surface of the PCB body 1 are installed Then, the large-size components 2 (large-size components with external pins, large-size components with internal pins, voltage regulators and sensors, etc.) are welded to the PCB board body 1, and a circuit test is performed; after the test is passed, the potting colloid 7 operation is performed, the potting head of the potting equipment is aligned with the injection hole 6, and then the potting colloid 7 is injected into the sealed cavity formed by the large-size components 2, the sealing seat 4, the retaining edge 5 and the PCB board body 1, and the large-size components 2 are filled and covered by the potting colloid 7, so that the lower part of the device body and the pins of the large-size components 2 are waterproofed, so that the PCB waterproof circuit board has a waterproof effect.

[0032] The waterproof coating is a nano waterproof coating; vacuum varnish coating is provided on both sides of the PCB body 1; the vacuum varnish coating can be used to apply glue to both sides of the PCB body 1; and the circuit wiring on the PCB body 1 is protected.

[0033] The sealing seat 4 is fixed to the PCB body 1 by bonding or welding. When welding, it is necessary to leave the pin mounting holes of the sealing seat 4 in advance when wiring the PCB body 1. Finally, the sealing seat 4 is directly welded to the PCB body 1 as a component. When bonding is adopted, adhesive is directly applied to the bottom of the sealing seat 4. Finally, the sealing seat 4 is bonded to the PCB body 1.

[0034] When the pins of the large-size component 2 are located outside the component body, the retaining edge 5 serves as a horizontal bar, and the potting colloid 7 is poured in from the top inner side of the sealing seat 4 and covers the pins of the large-size component 2; the bottom of the large-size component 2 is limited by the retaining edge 5, so that the pins of the large-size component 2 can be maintained at a set height, allowing the potting colloid 7 to smoothly enter and fill the inside of the sealing seat 4.

[0035] The PCB body 1 is installed on the external waterproof unit, and the external waterproof unit includes an upper shell 10 and a lower shell 11. The upper shell 10 and the lower shell 11 are integrally formed with a plurality of ear seats 12 on one side close to each other on the outside; the ear seats 12 are fastened by bolts and nuts, and a sealing ring is arranged between the upper shell 10 and the lower shell 11; the inner side of the upper shell 10 is integrally formed with an inner ring seat 13; a ring groove 14 is provided on the inner ring seat 13, a plurality of blind holes are provided on the inner edge of the top surface of the PCB body 1, and a pressure ring 15 is glued and fixed on the inner edge of the top surface of the PCB body 1; the pressure ring 15 is provided with an embedded column 16 embedded with the blind hole; the pressure ring 15 is embedded in the inner side of the ring groove 14; an epoxy resin sealing layer is provided between the outside of the PCB body 1 and the inside of the upper shell 10; a cable waterproof component is arranged at the end of the upper shell 10; the The cable 17 passes through the inner side of the cable waterproof assembly, and the cable 17 is electrically connected to the PCB board body 1. During installation, firstly, glue is applied to the inner edge of the top surface of the pressure ring 15 and the PCB board body 1, and then the cable 17 on the PCB board body 1 is led out from the cable waterproof assembly; then, the embedded column 16 of the pressure ring 15 is aligned and embedded with the blind hole of the PCB board body 1, so that the fitting surface of the PCB board body 1 and the pressure ring 15 form a sealing surface; then, the pressure ring 15 is aligned and embedded with the ring groove 14 of the inner ring seat 13, and finally, an epoxy resin sealing layer is coated and cured between the outside of the PCB board body 1 and the inside of the upper shell 10; so that a sealed cavity is formed between the inner side of the upper shell 10 and the PCB board body 1; finally, the upper shell 10 and the lower shell 11 are aligned, and the sealing ring is embedded, and finally, the ear seat 12 on the upper shell 10 and the lower shell 11 is fastened together by bolts and nuts.

[0036] The cable waterproof assembly includes a waterproof connector 18 which is fixedly engaged with the end of the upper shell 10; the upper shell 10 is integrally formed with a screw sleeve 19 on the outside of the waterproof connector 18, a sealing head 20 is screwed on the screw sleeve 19, and the cable 17 movably passes through the sealing head 20; a potting colloid 7 is arranged in the space formed by the screw sleeve 19 and the sealing head 20; during operation, the PCB board 1, the cable 17 and the waterproof connector 18 are connected first, then the cable 17 is passed through the sealing head 20, and the potting colloid 7 is injected into the screw sleeve 19 through the injection hole on the screw sleeve 19; thereby, the connection between the waterproof connector 18 and the cable 17 can be waterproofed.

[0037] A hygroscopic fiber felt 21 is bonded to the inner surface of the upper shell 10; an outer convex bin 22 is integrally formed on the outer top surface of the upper shell 10; an exhaust pipe 23 is embedded and fixed to the inner surface of the hygroscopic fiber felt 21 of the upper shell 10; the exhaust pipe 23 is connected to the outside of the outer convex bin 22, and two exhaust valves connected in series are arranged on the exhaust pipe 23, and the exhaust valves are connected to the PCB board 1; a pressure transmitter and a humidity transmitter are arranged on the PCB board 1; an inflation component is arranged on the upper shell 10; when the humidity transmitter detects that the water vapor inside the external waterproof unit reaches the set value, the external exhaust valve is opened first, so that the pipe section from the outside of the exhaust pipe 23 to the output end of the closed exhaust valve is at atmospheric pressure. state, then close the external exhaust valve, and open the internal exhaust valve. Since the pressure of the external waterproof unit is greater than the atmospheric pressure, the moisture inside the external waterproof unit can be discharged into the exhaust pipe 23 through the hygroscopic fiber felt 21. After the exhaust is completed, close the exhaust valve; the hygroscopic fiber felt 21 continues to absorb moisture, and when exhausting, the moisture on the hygroscopic fiber felt 21 can be carried away by the airflow, thereby maintaining the hygroscopicity of the hygroscopic fiber felt 21; when the pressure transmitter detects that the pressure is lower than the set value, the PCB board 1 sends a signal that inflation is required, and the inflation component inflates the inside of the external waterproof unit, and uses the pressure difference between the inside and outside of the external waterproof unit to prevent water vapor from entering the outside waterproof unit.

[0038] The inflation component is an inflation nozzle 22; when working, pressurized air is filled into the external waterproof unit through the inflation nozzle 22, so that the internal air pressure of the external waterproof unit reaches the set pressure.

[0039] The inflation assembly includes a pump group fixed on the inner side of the upper shell 10, and the input end of the pump group is connected to the output end of the exhaust pipe 23; the output end of the exhaust pipe 23 is connected in parallel with two one-way valves 24, and the one-way valves 24 are opened in opposite directions; the output end of the pump group is in a hollow state; the pump group is connected to the PCB board 1; when it is necessary to fill the internal part of the external waterproof unit with pressurized air, the pump group is turned on, and the air outside the external waterproof unit is filled into the exhaust pipe 23 through a one-way valve 24, and then filled into the internal part of the external waterproof unit through the pump group; when the internal part of the external waterproof unit reaches the set pressure value, the pump group is stopped; when the pump group inflates the external waterproof unit, the pump group outlet is directly opposite to the humidity transmitter. When the pump group is turned on, the humidity transmitter performs humidity sampling in real time. When the humidity exceeds the set value, the inflation is stopped and the inflation is postponed until a suitable inflation environment is detected for inflation. When multiple humidity samplings fail, a manual triggering inflation instruction is issued.

[0040] The above embodiments are only preferred implementations of the present invention, so any equivalent changes or modifications made according to the structures, features and principles described in the scope of application of the present invention are included in the scope of application of the present invention.

Claims

1. A PCB waterproof circuit board, comprising a PCB body, on which components are arranged and welded; characterized in that: The components include large-sized components whose height exceeds 6 mm on the top surface of the PCB body after welding and small-sized components whose height does not exceed 6 mm on the top surface of the PCB body after welding; and also include: A sealing seat, the sealing seat is fixed to the periphery of the large-sized components; the inner side of the sealing seat is a cavity with hollow ends, the inner side of the sealing seat is integrally formed with a retaining edge, the large-sized components are embedded in the inner side of the sealing seat and pressed with the retaining edge, and the large-sized components are welded to the PCB board; the PCB board is provided with a glue injection through hole on the inner side of the sealing seat; A potting colloid is poured into a sealed cavity formed by the large-sized components, the sealing seat, the retaining edge and the PCB body through the injection hole; the potting colloid covers the bottom surface of the large-sized components; The waterproof coating comprises a first waterproof coating and a second waterproof coating; after the small-sized components are welded to the PCB body, the first waterproof coating is coated on the top surface of the PCB body and the outside of the small-sized components; after all the components are welded, the second waterproof coating is coated on the bottom surface of the PCB body.

2. The PCB waterproof circuit board according to claim 1, characterized in that: The waterproof coating is a nano waterproof coating; and vacuum varnish coatings are provided on both sides of the PCB body.

3. The PCB waterproof circuit board according to claim 1, characterized in that: The sealing seat is fixed to the PCB body by bonding or welding.

4. The PCB waterproof circuit board according to claim 1, characterized in that: When the pins of the large-sized components are located outside the component body, the blocking edge is a horizontal bar, and the potting colloid is poured in from the top of the inner side of the sealing seat and covers the pins of the large-sized components.

5. The PCB waterproof circuit board according to claim 1, characterized in that: The PCB body is installed on the external waterproof unit, and the external waterproof unit includes an upper shell and a lower shell, and a plurality of ear seats are integrally formed on the outer side of the upper shell and the lower shell close to each other; the ear seats are fastened by bolts and nuts, and a sealing ring is arranged between the upper shell and the lower shell; an inner ring seat is integrally formed on the inner side of the upper shell; a ring groove is provided on the inner ring seat, a plurality of blind holes are provided on the inner edge of the top surface of the PCB body, and a pressure ring is glued and fixed on the inner edge of the top surface of the PCB body; an embedded column engaged with the blind hole is provided on the pressure ring; the pressure ring is embedded in the inner side of the ring groove; an epoxy resin sealing layer is provided between the outer side of the PCB body and the inner side of the upper shell; a cable waterproof assembly is arranged at the end of the upper shell; a cable passes through the inner side of the cable waterproof assembly, and the cable is electrically connected to the PCB body.

6. The PCB waterproof circuit board according to claim 5, characterized in that: The cable waterproof assembly includes a waterproof joint that is embedded and fixed at the end of the upper shell; the upper shell is integrally formed with a screw sleeve on the outside of the waterproof joint, a head is screwed on the screw sleeve, the cable movably passes through the head, and a potting colloid is arranged in the space formed by the screw sleeve and the head.

7. The PCB waterproof circuit board according to claim 5, characterized in that: The inner surface of the upper shell is bonded with a hygroscopic fiber felt; the outer top surface of the upper shell is integrally formed with an outer convex bin; an exhaust pipe is embedded and fixed to the inner surface of the hygroscopic fiber felt of the upper shell; the exhaust pipe is connected to the outside of the outer convex bin, and two exhaust valves connected in series are arranged on the exhaust pipe, and the exhaust valves are connected to the PCB board; the PCB board is provided with a pressure transmitter and a humidity transmitter; the upper shell is provided with an inflation assembly.

8. The PCB waterproof circuit board according to claim 7, characterized in that: The inflation component is an inflation nozzle.

9. The PCB waterproof circuit board according to claim 7, characterized in that: The inflation component includes a pump group fixed on the inner side of the upper shell, the input end of the pump group is connected to the output end of the exhaust pipe; the output end of the exhaust pipe is connected in parallel with two one-way valves, and the opening directions of the one-way valves are opposite; the output end of the pump group is in a hollow state; the pump group is connected to the PCB board.

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