Centrifugal welding apparatus and method for radio frequency interference filters

Abstract

The application discloses a centrifugal welding device and a welding method for a radio frequency interference filter, and belongs to the technical field of radio frequency interference filter production. The centrifugal welding device comprises a support, a motor, a rotating seat, a workpiece clamp, an inert gas tank, a heating piece and a gas pipe. The rotating seat is installed on the support through bearings. The workpiece clamp is installed on the rotating seat. A plurality of clamping grooves are arranged in the workpiece clamp. An air passage through hole is arranged in the rotating seat. One end of the gas pipe is connected with the inert gas tank, and the other end is arranged in the air passage through hole. The heating piece is arranged in the gas pipe. The rotating shaft of the motor is in transmission connection with the rotating seat. The welding method comprises rotating speed control of the motor and temperature control in the workpiece clamp. The workpiece is arranged in the high-speed rotating workpiece clamp, so that the solder is more uniformly and reliably filled into the welding seams on the inner and outer sides of the porcelainized capacitor under the action of the centrifugal force. The welding effect with higher quality is realized, and the welding cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of radio frequency interference filter manufacturing technology, specifically relating to a processing equipment for radio frequency interference filters, and more particularly to a centrifugal welding equipment and welding method for radio frequency interference filters. Background Technology

[0002] Radio frequency (RF) interference filters are suitable for electronic equipment, instruments, and meters that require protection against RF interference, and are widely used in aerospace systems to suppress interference signals introduced by power lines. For example... Figure 1 As shown, the main components of the radio frequency interference filter include a ceramic capacitor 4, a lead wire 1, and a housing 6. The ceramic capacitor 4 is placed inside the housing 6. The lead wire 1 passes through the central through-hole of the housing 6 and the central through-hole of the ceramic capacitor 4. The lead wire 1 is electrically connected to the wall of the central through-hole of the ceramic capacitor 4 (i.e., the inner electrode of the ceramic capacitor 4), and the outer wall of the ceramic capacitor 4 (i.e., the outer electrode of the ceramic capacitor 4) is electrically connected to the inner wall of the housing 6 via solder 3. A glass 7 is provided between the inner wall of one end of the housing 6 and the lead wire 1, and an epoxy resin 2 is provided between the inner wall of the other end of the housing 6 and the lead wire 1. The glass 7, the housing 6, and the lead wire 1 are pre-sintered at high temperature to form a semi-sealed structure with one end encapsulated by the glass 7. Figure 1 The image also shows red adhesive 5 on the glass 7, which is used to isolate the inner and outer ring solder to prevent the lead wire 1 and the housing 6 from conducting and to position the ceramic capacitor 4 before soldering.

[0003] The production process of the aforementioned radio frequency interference filter mainly includes assembly, soldering, cleaning, and potting. Soldering is a crucial manufacturing process that electrically connects the lead wire 1 to the wall of the central through-hole of the ceramic capacitor 4, and the outer wall of the ceramic capacitor 4 to the inner wall of the outer casing 6, using solder 3. Reflow soldering is typically used for this process. Because the radio frequency interference filter is small, with an installation diameter typically around Φ3mm, the weld width used for soldering is only about 0.05mm. This extremely small soldering space can lead to quality problems such as solder runoff, incomplete solder joints, and voids in the solder joints. Specifically, traditional soldering methods used in the production of radio frequency interference filters have the following drawbacks: First, the welding equipment used is conventional reflow soldering equipment (tunnel furnace), which is suitable for a volume of only about 20mm. 3 For radio frequency interference filters, the internal space of reflow soldering equipment is too large, usually more than ten million times the volume of the filter. Its lateral temperature control accuracy is low, and the products are prone to different heating due to different placement positions, resulting in poor soldering quality. Moreover, the energy consumption during production is very high, resulting in high production costs.

[0004] Secondly, during soldering, lead 1 is positioned vertically by a clamp. During the high-temperature soldering process, the weld seam not filled with paste solder (a solder alloy) is occupied by air. This air expands when heated and carries flux upwards to evaporate and migrate, thereby pushing the molten paste solder upwards and climbing to the end face and outer wall of the outer casing 6, resulting in product appearance defects and insufficient solder at the solder joints. At the same time, the flux that has not overflowed will remain inside the solder joints, increasing the risk of the product absorbing moisture and reducing its insulation performance.

[0005] Third, during high-temperature soldering, the inconsistent filling state of the solder joints by the paste solder for each product, coupled with the different thermal expansion states of the air inside the solder joints, makes the solder flow state almost uncontrollable at high temperatures, ultimately resulting in poor consistency in the soldering effect of the same batch of products. In addition, since the paste solder cannot be evenly applied around the solder joints at 360°, it exacerbates the phenomenon of insufficient solder in some solder joints. Therefore, traditional technology cannot guarantee the 360° integrity of the solder joints, affecting the geometric structure and impedance characteristics of the solder joints, resulting in poor product filtering performance.

[0006] Fourth, the quality problems caused by traditional reflow soldering mainly occur in the high-temperature zone (reflow zone) of the soldering process. If the reflow time is too long, it will help the gas escape and reduce the voids in the solder joint. However, if the time is too long, the flux will be exhausted and lose its protective function, which will aggravate the oxidation of the solder and reduce the wettability and fluidity of the solder. This will not only lead to rough and dull solder joints, but may even cause cold solder joints. If the reflow time is too short, the solder will not be able to flow and spread sufficiently before being cooled quickly. This will not only cause cold solder joints with a granular appearance and poor wetting, but also cause the gas generated by flux residue and decomposition to not have time to escape from the solder and form voids, resulting in unreliable soldering quality. Summary of the Invention

[0007] The purpose of this invention is to provide a centrifugal welding device and welding method for radio frequency interference filters with higher welding quality in order to solve the above-mentioned problems.

[0008] The present invention achieves the above objectives through the following technical solutions: A centrifugal welding device for radio frequency interference filters includes a support, a motor, a rotating base, a workpiece clamp, an inert gas tank, a heating element, and a gas pipe. The rotating base is mounted on the support via bearings and can rotate freely. The workpiece clamp is mounted on top of the rotating base and has an inner cavity. The inner cavity wall has multiple vent holes. The workpiece clamp has multiple clamping slots arranged circumferentially and communicating with the inner cavity for clamping workpieces. The rotating base has a vertical vent hole, the upper end of which communicates with the inner cavity of the clamp. One end of the gas pipe is connected to the outlet of the inert gas tank, and the other end is placed in the vent hole. The heating element is placed inside the gas pipe. The motor is mounted on the support, and the motor shaft is drivenly connected to the rotating base.

[0009] Preferably, to facilitate processing and assembly and reliably mount multiple workpieces on the circumferential edge of the workpiece fixture to achieve better centrifugal rotation, the workpiece fixture includes an interconnected circular upper fixture disk and a circular lower fixture disk. The lower surface of the upper fixture disk has an upper circular recess in the center and an outer annular surface with multiple upper clamping grooves arranged circumferentially. The upper surface of the lower fixture disk has a lower circular recess in the center and an outer annular surface with multiple lower clamping grooves arranged circumferentially. A central through hole for the lower fixture disk is located at the center of the bottom of the lower circular recess. The upper and lower circular recesses are joined together to form the inner cavity of the fixture. Multiple vent holes are provided on the circumferential groove wall of the upper clamping plate and the circumferential groove wall of the lower clamping plate, respectively. Connecting lugs for mutual connection are provided on the outer circumferential edges of the upper clamping plate and the lower clamping plate, respectively. Multiple upper clamping grooves and multiple lower clamping grooves are respectively connected to form multiple clamping grooves for clamping the outer shell of the workpiece. A lead wire groove for the lead wire of the workpiece to pass through is provided near the center of the bottom of the groove on the outer side of each clamping groove. A circular mounting groove is provided on the top of the rotating seat. The upper end of the vent hole is located at the center of the mounting groove. The lower clamping plate is installed in the mounting groove. The upper end of the vent hole is connected to the central through hole of the lower clamping plate.

[0010] Preferably, in order to reliably connect the workpiece fixture and the rotating seat, the bottom of the mounting groove is provided with a plurality of mounting screw holes evenly distributed in the circumferential direction at the position of the outer periphery of the vent hole, and the bottom of the lower circular groove is provided with a plurality of mounting through holes evenly distributed in the circumferential direction at the position of the outer periphery of the central through hole of the lower fixture plate, and a plurality of mounting screws pass through the plurality of mounting through holes and are connected to the plurality of mounting screw holes.

[0011] Preferably, to facilitate the rotational installation of the rotary seat and its connection with the workpiece fixture, the upper section of the rotary seat is a cone with a larger upper section and a smaller lower section is a cylinder. The vent hole passes through the cylinder and the cone. The cylinder is mounted on the bracket via the bearing, and the workpiece fixture is mounted on the cone.

[0012] Preferably, in order to reduce heat loss and facilitate reliable transmission connection between the motor shaft and the rotating seat, an insulation layer is provided between the air pipe and the air vent, the motor shaft is connected to the driving gear, and the outer circumferential wall of the cylinder is provided with a driven gear, which is connected to the driving gear through a toothed belt.

[0013] Preferably, in order to facilitate exhaust and control of air pressure and temperature inside the fixture cavity, an exhaust pipe is installed on the bracket. The lower section of the exhaust pipe has a larger diameter than the upper section and its lower section is located outside the rotating seat and the workpiece fixture. An exhaust fan is installed on the upper section of the exhaust pipe.

[0014] Preferably, to facilitate automated control during the welding process, a negative pressure sensor is installed on the inner wall of the lower section of the exhaust pipe; the heating element is an electric heating wire, located close to the inner cavity of the fixture; a temperature sensor is installed on the inner wall of the gas pipe between the heating element and the inner cavity of the fixture; the inert gas tank is a nitrogen tank, with a nitrogen valve installed at the outlet; a flow meter is installed on the gas pipe; the signal output terminals of the negative pressure sensor, the temperature sensor, and the flow meter are respectively connected to the signal input terminal of the controller; and the control input terminals of the heating element, the motor, the nitrogen valve, and the exhaust fan are respectively connected to the control output terminal of the controller.

[0015] A welding method using a centrifugal welding device for radio frequency interference filters includes the following steps: Step 1: Install multiple workpieces to be soldered and filled with solder paste into the workpiece fixture; Step 2: The controller controls the motor rotor to gradually increase its speed from 0 rpm to 500 rpm to 5000 rpm within 10 to 120 seconds and maintain this speed. Simultaneously, the controller controls the opening and degree of the nitrogen valve based on the flow meter's detection signal, and controls the opening and degree of the exhaust fan based on the negative pressure sensor's detection signal. In this step, the controller controls the opening and degree of the nitrogen valve and the exhaust fan; the specific control method depends on actual needs and is not limited here. Step 3: The controller controls the heating element to raise the temperature of the fixture cavity from room temperature to the active temperature of the paste solder at a heating rate of 1℃ / s to 3℃ / s according to the detection signal of the temperature sensor and maintain it for 40s to 100s. Then, the temperature of the fixture cavity is raised to the liquidus temperature of the paste solder at a heating rate of 2℃ / s to 5℃ / s. Then, the temperature of the fixture cavity is raised to the highest temperature of the paste solder at a heating rate of 2℃ / s to 5℃ / s and maintained for 5s to 60s. Then, the temperature of the fixture cavity is cooled down to the liquidus temperature of the paste solder. Step 4: The controller controls the heating element to cool the temperature of the fixture cavity to room temperature at a cooling rate of 2℃ / s to 4℃ / s according to the detection signal of the temperature sensor. Then the controller controls the rotor of the motor to decrease to 0 rpm. Step 5: The controller controls the nitrogen valve, the motor, the exhaust fan and the heating element to shut down, opens the workpiece fixture, removes the welded workpiece, and completes the welding process.

[0016] The beneficial effects of this invention are as follows: This invention, through the design of a mutually cooperating support, motor, rotating base, workpiece fixture, inert gas tank, heating element, and gas pipe, enables the simultaneous batch welding of multiple workpieces using appropriately sized equipment. By placing the workpieces in a high-speed rotating fixture, centrifugal force allows the solder to fill the weld seams on both the inner and outer sides of the ceramic capacitor more evenly and reliably, thereby achieving higher welding quality and reducing welding costs. Specific advantages are as follows: First, the welding equipment is much smaller, about several thousand times the size of an RF interference filter, compared to traditional reflow soldering equipment which is about ten million times larger. This significantly reduces the size and cost of the equipment. At the same time, the rotating seat makes the temperature distribution inside the fixture cavity more uniform, the welding environment temperature of the same batch of workpieces is more consistent, and the temperature control is more precise, thus improving the welding quality. Secondly, by altering the stress state of the liquefied solder through centrifugal force, the solder can flow into the ultra-narrow weld seam, thereby significantly improving the welding quality and effectively preventing solder from overflowing, ensuring the product's appearance quality and the fullness of the solder joints. Third, during welding, the solder is subjected to uniform and controllable force (by controlling the motor speed), the solder flow is controllable, the product consistency is good, and 360° perfect welding of the solder joints can be achieved, and the product has good filtering performance. Fourth, the welding method of the present invention facilitates precise control of process parameters such as rotation speed, temperature, and negative pressure, ensuring stability and reliability. It effectively avoids problems such as voids in the weld joint and flux residue, and the product has high reliability when used in harsh environments for a long time. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the front half-section structure of the radio frequency interference filter; Figure 2 This is a front view schematic diagram of the centrifugal welding equipment for radio frequency interference filters according to the present invention. The figure shows the internal structure of the exhaust pipe, workpiece clamp and rotary seat. Figure 3 yes Figure 2 The enlarged view marked "A" shows the internal structure of the exhaust pipe, workpiece fixture, and rotary seat; Figure 4 This is a three-dimensional structural diagram of the rotary seat and workpiece fixture of the centrifugal welding equipment for radio frequency interference filters described in this invention before assembly. Figure 5 This is a three-dimensional structural diagram of the rotating base of the centrifugal welding equipment for radio frequency interference filters described in this invention; Figure 6 This is a three-dimensional structural diagram of the lower clamping disk of the centrifugal welding equipment for radio frequency interference filters described in this invention; Figure 7 This is a process curve diagram of the welding method of the centrifugal welding equipment for radio frequency interference filters described in this invention. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings: like Figures 2-6 As shown, the centrifugal welding equipment for radio frequency interference filters of the present invention includes a support 12, a motor 23, a rotating base 20, a workpiece clamp (refer to the upper clamp plate 16 and lower clamp plate 17 in the following description), an inert gas tank 9, a heating element 19, and a gas pipe 11. The rotating base 20 is mounted on the support 12 via bearings 21 and can rotate freely. The workpiece clamp is mounted on the rotating base 20 and has an inner cavity (not marked in the figure). The inner cavity wall of the workpiece clamp has multiple exhaust holes 27. The workpiece clamp has multiple parts for clamping workpieces (refer to...). Figure 1 The structure of the radio frequency interference filter after removing the epoxy resin 2) and the clamping grooves arranged in the circumferential direction and communicating with the inner cavity of the fixture (refer to the lower clamping groove 34 and the upper clamping groove in the following content). The rotating seat 20 is provided with a vertical ventilation hole 32. The upper end of the ventilation hole 32 is connected to the inner cavity of the fixture. One end of the air pipe 11 is connected to the outlet of the inert gas tank 9, and the other end is placed in the ventilation hole 32. The heating element 19 is placed in the air pipe 11. The motor 23 is mounted on the bracket 12, and the rotating shaft of the motor 23 is connected to the rotating seat 20 for transmission.

[0019] like Figures 2-6 As shown, the present invention also discloses the following more optimized specific structures: To facilitate processing and assembly, and to reliably mount multiple workpieces on the circumferential edge of the workpiece fixture for better centrifugal rotation, the workpiece fixture includes an interconnected circular upper clamping disk 16 and a circular lower clamping disk 17. The lower surface of the upper clamping disk 16 has an upper circular recess (not shown in the figure, so it is not marked; refer to the structure of the lower circular recess 33 for a clear understanding), and an outer annular surface with multiple upper clamping grooves arranged circumferentially on this surface (not clearly shown in the figure, so it is not marked; refer to the structure of the lower clamping groove 34 for a clear understanding). The upper surface of the lower clamping disk 17 has a lower circular recess 33 in the center. 3. An annular surface is formed on the outside, and multiple lower clamping grooves 34 are arranged circumferentially on this annular surface. A central through hole 35 of the lower clamping plate is provided at the center of the bottom of the lower circular groove 33. The upper and lower circular grooves 33 are connected to each other to form the inner cavity of the clamp. Multiple exhaust holes 27 are provided on the circumferential groove wall of the upper clamping plate 16 and the circumferential groove wall of the lower clamping plate 17, respectively. Connecting lugs 26 for mutual connection are provided on the outer peripheral edges of the upper clamping plate 16 and the lower clamping plate 17, respectively. Multiple upper clamping grooves and multiple lower clamping grooves 34 are connected to each other to form multiple outer shells for clamping the workpiece (see reference). Figure 1 The clamping groove of the outer casing 6) has a lead wire for the workpiece (see reference) provided near the center of the groove bottom on the outer side of each clamping groove. Figure 1 The lead wire 1) passes through the lead wire groove (not marked in the figure). The rotating seat 20 is provided with a circular mounting groove 30. The upper end of the vent hole 32 is located at the center of the mounting groove 30. The lower clamping plate 17 is installed in the mounting groove 30. The upper end of the vent hole 32 is connected to the center through hole 35 of the lower clamping plate.

[0020] In order to reliably connect the workpiece fixture and the rotating seat 20, a plurality of mounting screw holes 31 (four in the figure) are provided in the bottom of the mounting groove 30 at the position of the outer periphery of the ventilation hole 32. A plurality of mounting through holes 36 (four in the figure) are provided in the bottom of the lower circular groove 33 at the position of the outer periphery of the central through hole 35 of the lower fixture plate. A plurality of mounting screws (not marked in the figure) pass through the plurality of mounting through holes 36 and are connected to the plurality of mounting screw holes 31.

[0021] To facilitate the rotational installation of the rotary seat 20 and its connection with the workpiece fixture, the upper section of the rotary seat 20 is a cone (not separately marked, i.e., the marked position of the rotary seat 20 in the figure), and the lower section is a cylinder 28. The ventilation hole 32 passes through the cylinder 28 and the cone. The cylinder 28 is mounted on the bracket 12 via the bearing 21, and the workpiece fixture is mounted on the cone.

[0022] In order to reduce heat loss and facilitate reliable transmission connection between the shaft of motor 23 and the rotating seat 20, an insulation layer 25 is provided between the air pipe 11 and the air vent 32. The shaft of motor 23 is connected to the driving gear (not visible in the figure). The outer circumference of cylinder 28 is provided with driven gear 29, and the driven gear 29 is connected to the driving gear through a toothed belt 22.

[0023] To facilitate exhaust and control of air pressure and temperature within the fixture cavity, an exhaust pipe 13 is installed on the bracket 12. The lower section of the exhaust pipe 13 has a larger diameter than the upper section, and its lower section is located outside the rotating seat 20 and the workpiece fixture. An exhaust fan 15 is installed on the upper section of the exhaust pipe 13.

[0024] To facilitate automated control during the welding process, a negative pressure sensor 14 is installed on the inner wall of the lower section of the exhaust pipe 13. The heating element 19 is an electric heating wire, located close to the inner cavity of the fixture. A temperature sensor 18 is installed on the inner wall of the gas pipe 11 between the heating element 19 and the inner cavity of the fixture. The inert gas tank 9 is a nitrogen tank, and a nitrogen valve 8 is installed at the outlet of the inert gas tank 9. A flow meter 10 is installed on the gas pipe 11. The signal output terminals of the negative pressure sensor 14, the temperature sensor 18, and the flow meter 10 are respectively connected to the signal input terminal of the controller. The control input terminals of the heating element 19, the motor 23, the nitrogen valve 8, and the exhaust fan 15 are respectively connected to the control output terminal of the controller. The controller is represented by a computer 24 in the figure, but it can also be a PLC. Preferably, a PID control system is installed inside. The PID control system, short for proportional-integral-derivative control system, is a control strategy widely used in the field of industrial automation.

[0025] Combination Figures 1-7 The welding method of the centrifugal welding equipment for radio frequency interference filters described in this invention includes the following steps: Step 1: Place multiple workpieces to be soldered and filled with solder paste (see reference). Figure 1 The radio frequency interference filter shown (but the workpiece is a product that has not been potted with epoxy resin 2 and has been filled with paste solder) has its outer shell 6 installed in the workpiece fixture and the upper fixture plate 16 and the lower fixture plate 17 are connected. Because the outer diameter of the outer shell 6 is significantly larger than the diameter of the lead wire 1, the outer side of the clamping groove has a step to ensure that the entire workpiece will not detach from the workpiece fixture when subjected to centrifugal force. Step 2: The controller controls the rotor of motor 23 to gradually increase its speed from 0 rpm to 500 rpm to 5000 rpm within a time period of 10s to 120s and maintain this speed. The acceleration process is... Figure 7 The acceleration region corresponds to the process, and the hold process is... Figure 7The process corresponds to the preheating zone and welding zone in the process; at the same time, the controller controls the opening and degree of the nitrogen valve 8 according to the detection signal of the flow meter 10, and the controller controls the opening and degree of the exhaust fan 15 according to the detection signal of the negative pressure sensor 14; in this step, the controller controls the opening and degree of the nitrogen valve 8 and the controller controls the opening and degree of the exhaust fan 15. The specific control method depends on the actual needs and is not limited here. Step 3, Reference Figure 7 The controller, based on the detection signal from the temperature sensor 18, controls the heating element 19 to raise the temperature of the fixture cavity from room temperature to the active temperature of the paste solder (depending on the type of solder, such as 100℃ to 160℃) at a heating rate of 1℃ / s to 3℃ / s and maintain it for 40s to 100s. Then, it raises the temperature of the fixture cavity to the liquidus temperature of the paste solder (depending on the type of solder, such as 180℃ to 230℃) at a heating rate of 2℃ / s to 5℃ / s, then raises the temperature of the fixture cavity to the highest temperature of the paste solder (depending on the type of solder, such as 240℃) at a heating rate of 2℃ / s to 5℃ / s and maintains it for 5s to 60s. Finally, it cools the temperature of the fixture cavity back to the liquidus temperature of the paste solder. This temperature control process is... Figure 7 The heating and initial cooling processes corresponding to the preheating zone and welding zone in the process; Step 4: The controller, based on the detection signal from the temperature sensor 18, controls the heating element 19 to cool the temperature of the fixture cavity to room temperature at a cooling rate of 2℃ / s to 4℃ / s. Then, the controller controls the motor rotor to decrease to 0 rpm; the above cooling process is... Figure 7 The cooling process corresponding to the intermediate cooling zone, the aforementioned deceleration process is... Figure 7 The deceleration process corresponding to the mid-cooling zone; Step 5: The controller shuts off the nitrogen valve 8, motor 23, exhaust fan 15, and heating element 19, opens the workpiece fixture, and removes the welded workpiece, completing the welding process. The workpiece then undergoes a cleaning and epoxy resin potting process to obtain the radio frequency interference filter.

[0026] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the technical solutions of the present invention. Any technical solution that can be implemented based on the above embodiments without creative effort should be considered to fall within the scope of protection of the patent of the present invention.

Claims

1. A centrifugal welding apparatus for radio frequency interference filters, characterized by: The device includes a support frame, a motor, a rotating base, a workpiece clamp, an inert gas tank, a heating element, and air pipes. The rotating base is mounted on the support frame via bearings and can rotate freely. The workpiece clamp is mounted on top of the rotating base and has an inner cavity. The inner cavity wall has multiple vent holes. The workpiece clamp has multiple clamping slots arranged circumferentially and communicating with the inner cavity for clamping workpieces. The rotating base has vertical vent holes, the upper ends of which are connected to the clamping unit. The device has an internal cavity that is interconnected. One end of the air pipe is connected to the outlet of the inert gas tank, and the other end is placed in the vent hole. The heating element is placed inside the air pipe. The motor is mounted on the bracket, and the motor shaft is drivenly connected to the rotating seat. The workpiece fixture includes an interconnected circular upper fixture plate and a circular lower fixture plate. The lower surface of the upper fixture plate has an upper circular groove in the middle and forms an annular surface on the outside. This annular surface has multiple upper clamping grooves arranged along the circumferential direction. The lower fixture... The upper surface of the clamping disc has a lower circular recess in the middle, forming an outer annular surface with multiple lower clamping grooves arranged circumferentially on the annular surface. A central through hole for the lower clamping disc is located at the center of the bottom of the lower circular recess. The upper and lower circular recesses are joined together to form the clamping cavity. Multiple exhaust holes are provided on the circumferential groove walls of both the upper and lower clamping discs. The outer edges of both the upper and lower clamping discs are respectively provided with... The connecting lugs, one-to-one corresponding to the multiple upper clamping slots and multiple lower clamping slots respectively, form multiple clamping slots for clamping the outer shell of the workpiece. Each clamping slot has a lead wire slot near the center of the bottom of the slot on the outer side for the lead wire of the workpiece to pass through. The rotating seat has a circular mounting groove on its top. The upper end of the vent hole is located at the center of the mounting groove. The lower clamping plate is installed in the mounting groove. The upper end of the vent hole is connected to the center through hole of the lower clamping plate.

2. The centrifugal welding apparatus for radio frequency interference filters of claim 1, wherein: The bottom of the mounting trough has multiple mounting screw holes evenly distributed along the circumference at the outer periphery of the vent hole. The bottom of the lower circular trough has multiple mounting through holes evenly distributed along the circumference at the outer periphery of the central through hole of the lower clamping plate. Multiple mounting screws pass through the multiple mounting through holes and connect to the multiple mounting screw holes.

3. A centrifugal welding apparatus for radio frequency interference filters according to claim 1 or 2, characterised in that: The upper section of the rotating seat is a cone that is larger at the top and smaller at the bottom, and the lower section is a cylinder. The vent hole passes through the cylinder and the cone. The cylinder is mounted on the bracket through the bearing, and the workpiece clamp is mounted on the cone.

4. The centrifugal welding equipment for radio frequency interference filters according to claim 3, characterized in that: An insulation layer is provided between the air pipe and the air vent. The motor shaft is connected to the drive gear. The outer circumference of the cylinder is provided with a driven gear, and the driven gear is connected to the drive gear by a toothed belt drive.

5. The centrifugal welding equipment for radio frequency interference filters according to claim 1 or 2, characterized in that: An exhaust pipe is installed on the bracket. The lower section of the exhaust pipe has a larger diameter than the upper section and is located outside the rotating seat and the workpiece fixture. An exhaust fan is installed on the upper section of the exhaust pipe.

6. The centrifugal welding equipment for radio frequency interference filters according to claim 5, characterized in that: A negative pressure sensor is installed on the inner wall of the lower section of the exhaust pipe. The heating element is an electric heating wire, which is close to the inner cavity of the clamp. A temperature sensor is installed on the inner wall of the air pipe between the heating element and the inner cavity of the clamp. The inert gas tank is a nitrogen tank, and a nitrogen valve is installed at the outlet of the inert gas tank. A flow meter is installed on the air pipe. The signal output terminals of the negative pressure sensor, the temperature sensor, and the flow meter are respectively connected to the signal input terminal of the controller. The control input terminals of the heating element, the motor, the nitrogen valve, and the exhaust fan are respectively connected to the control output terminal of the controller.

7. A welding method for a centrifugal welding apparatus for a radio frequency interference filter as described in claim 6, characterized in that: Includes the following steps: Step 1: Install multiple workpieces to be soldered and filled with solder paste into the workpiece fixture; Step 2: The controller controls the rotor of the motor to gradually increase its speed from 0 rpm to 500 rpm to 5000 rpm within 10s to 120s and maintain this speed; at the same time, the controller controls the opening of the nitrogen valve and its opening degree according to the detection signal of the flow meter, and the controller controls the opening of the exhaust fan and its opening degree according to the detection signal of the negative pressure sensor. Step 3: The controller controls the heating element to raise the temperature of the fixture cavity from room temperature to the active temperature of the paste solder at a heating rate of 1℃ / s to 3℃ / s according to the detection signal of the temperature sensor and maintain it for 40s to 100s. Then, the temperature of the fixture cavity is raised to the liquidus temperature of the paste solder at a heating rate of 2℃ / s to 5℃ / s. Then, the temperature of the fixture cavity is raised to the highest temperature of the paste solder at a heating rate of 2℃ / s to 5℃ / s and maintained for 5s to 60s. Then, the temperature of the fixture cavity is cooled down to the liquidus temperature of the paste solder. Step 4: The controller controls the heating element to cool the temperature of the fixture cavity to room temperature at a cooling rate of 2℃ / s to 4℃ / s according to the detection signal of the temperature sensor. Then the controller controls the rotor of the motor to decrease to 0 rpm. Step 5: The controller controls the nitrogen valve, the motor, the exhaust fan and the heating element to shut down, opens the workpiece fixture, removes the welded workpiece, and completes the welding process.

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