Low-inductance direct-current pulse capacitor and manufacturing method thereof

Abstract

The invention discloses a low-inductance direct current pulse capacitor, which relates to the technical field of capacitors, and specifically comprises a capacitor shell and a capacitor body sleeved in the capacitor shell, a filling space is arranged between the capacitor shell and the capacitor body, and the top and the bottom of the capacitor shell are both provided with conical blind holes and composite flow channels. The adjacent conical blind holes are communicated with the composite flow channel space, and composite plug blocks are embedded in the conical blind holes. According to the low-inductance direct-current pulse capacitor, the conical blind holes and the composite runners are formed in the top and the bottom of the capacitor shell, so that the two conical blind holes and the two composite runners are matched in pairs to form two glue injection channels, and then the two composite plug blocks, the glue injection mechanism and the jig mechanism are matched; glue injection filling can be carried out on a gap between the capacitor shell and the capacitor body from bottom to top, air can be discharged without penetrating through a glue layer, bubble residues in a top dead zone are effectively avoided, and the processing quality is improved.

Description

Technical Field

[0001] This invention relates to the field of capacitor technology, specifically to a low-inductance DC pulse capacitor and its manufacturing method. Background Technology

[0002] Low-inductance DC pulse capacitors are special energy storage components capable of charging over a relatively long period and discharging in an extremely short time to generate enormous pulse power. Their core characteristic is extremely low equivalent series inductance. These capacitors typically employ a metallized polypropylene film non-inductive wound or laminated structure as the core component to reduce internal inductance. The two ends of the component are gold-plated to form low-impedance electrode contact surfaces, and are connected to terminals via wide, thin lead sheets or connecting copper sheets to shorten the current path and further counteract the magnetic field. The overall structure also includes a housing for insulation and fixation, and terminals for mounting and current extraction. Due to their high pulse current, high voltage tolerance, and rapid charging and discharging characteristics, these capacitors are widely used in fields requiring instantaneous high energy, such as laser power supplies, medical equipment, energy storage and spot welding machines, magnetizers and demagnetizers, and IGBT snubber circuits and inverters in power electronic equipment. They also play a crucial role in cutting-edge scientific research fields such as high-energy physics, high-power lasers, and controlled nuclear fusion.

[0003] Currently, in the production process of low-inductance DC pulse capacitors, existing technologies take into account the microscopic gaps between the capacitor cores and between the cores and the casing. If these gaps are filled with air, the air will ionize under a high electric field, resulting in partial discharge. Long-term operation can lead to insulation aging and failure. To address this, pre-drill holes on the casing surface and fill these gaps with adhesive through these holes after the capacitor hardware is assembled. This utilizes the high dielectric constant and high breakdown strength of insulating materials (such as epoxy resin) to eliminate air gaps and significantly improve the product's initial partial discharge voltage. However, for the processed hole structure, although the existing hot-melt welding method can ensure a sealing effect, residual gas, moisture evaporation, or uneven heat dissipation in the material during welding can easily form pores and air pockets inside the weld, causing structural discontinuity and directly affecting the integrity of the seal. The local high temperature in the welding area can cause thermal stress at the interface between the cured epoxy resin and the casing, which can lead to microcracks in severe cases. These defects can become the initiation point of partial discharge under high voltage, ultimately affecting the long-term reliability and service life of the capacitor. Therefore, in view of the problems existing in the prior art, the applicant will provide a low-inductance DC pulse capacitor and a method for manufacturing the same to solve the problem. Summary of the Invention

[0004] This invention provides a low-inductance DC pulse capacitor, which solves the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a low-inductance DC pulse capacitor, comprising a capacitor shell and a capacitor body fitted inside the capacitor shell, wherein a filling space is provided between the capacitor shell and the capacitor body, and the top and bottom of the capacitor shell are provided with conical blind holes and composite flow channels, and adjacent conical blind holes communicate with the composite flow channel space, a composite plug is nested inside the conical blind hole, and a clearance space is provided in the middle of the composite plug that communicates with the composite flow channel space, and a potting mechanism is fitted inside the composite plug located at the bottom of the capacitor shell, a base is provided at the bottom of the capacitor shell, and a fixture mechanism for clamping and limiting the capacitor shell is provided at the top of the base;

[0006] The rear end of the base is respectively equipped with a bidirectional lead screw and a brake servo motor. Both ends of the bidirectional lead screw are threaded with U-shaped pressure plates, and one end of the bidirectional lead screw is driven to the output end of the brake servo motor installed on the inner wall of the bottom of the base. The two U-shaped pressure plates move close to each other under the combined drive of the bidirectional lead screw and the brake servo motor. During the movement of the two U-shaped pressure plates, they can press the two composite plugs respectively, so that the two composite plugs respectively close the two composite channels in a staggered manner.

[0007] Preferably, the composite flow channel includes an annular groove and a plurality of transition holes, wherein the plurality of transition holes are arranged along the circumference of the annular groove, and the port of the transition hole away from the annular groove communicates with the internal space of the capacitor housing.

[0008] Preferably, the composite plug includes a hollow plug cylinder, a first sealing ring, and a second sealing ring. The hollow plug cylinder has a side flow hole in its middle as a clearance space, and the side flow hole can communicate with the annular groove space. The first sealing ring and the second sealing ring are respectively fitted on the middle surface and the outer side of one end of the hollow plug cylinder. The bottom of the first sealing ring is tightly engaged with the end space of the conical blind hole near the capacitor body. After the hollow plug cylinder is further displaced under pressure, the second sealing ring can cover and seal the open area of ​​the annular groove.

[0009] Preferably, the inner wall of the port of the tapered blind hole away from the capacitor body is provided with an internal thread, the surface of the other end of the hollow plug is provided with a reinforced external thread that can engage with the internal thread, and the end of the other end of the hollow plug is provided with an internal hexagonal groove.

[0010] Preferably, the outer sides of both ends of the bidirectional lead screw are fitted with auxiliary guide brackets fixed to the inner wall of the bottom of the base, and the front end structure of the auxiliary guide brackets is engaged with the middle of the two U-shaped pressure plates. The bidirectional lead screw consists of a main rod and two lead screws with opposite conveying directions, and one end of the two lead screws is respectively connected to the two ends of the main rod for transmission. Nuts that can be threadedly connected to the lead screws are fixedly nested inside the two U-shaped pressure plates. The middle of the main rod is fitted with an auxiliary frame fixed to the top of the rear end of the base through a bearing.

[0011] Preferably, the dispensing mechanism includes a dispensing tube, a flow guide valve tube, and a third electric push rod. One end of the dispensing tube is designed with a tapered structure and fitted with a buffer ring. One end of the flow guide valve tube is fitted onto one side of the bottom of the dispensing tube. The third electric push rod is installed on the inner wall of the bottom of the base, and a linkage plate is installed between the output end of the third electric push rod and the bottom of the dispensing tube.

[0012] Preferably, the fixture mechanism includes a positioning bracket and two limiting components. The positioning bracket is fixedly sleeved inside the base, and buffer grooves are opened on both sides of the bottom of the positioning bracket. Several friction-reducing rollers that can roll and contact the capacitor shell with the ground are arranged in the buffer grooves.

[0013] Preferably, the limiting component includes a support cylinder, a first electric push rod, a limiting pressure plate, and a rotational clearance structure. One end of the support cylinder is fitted with a bearing seat fixed to the top of the base via a bearing assembly, and the other end of the support cylinder is fitted with the housing of the first electric push rod. The output end of the first electric push rod is connected to the middle of the limiting pressure plate via a transmission connection, and the limiting pressure plate, under the transmission of the first electric push rod, can cooperate with the positioning bracket to automatically clamp and limit the assembly formed by the capacitor housing and the capacitor body.

[0014] Preferably, the rotational clearance structure includes two gears, a U-shaped toothed plate, and a second electric push rod. The two gears are respectively fitted onto the outer side of one end of the two support cylinders and then respectively mesh with the two sides of the U-shaped toothed plate. The second electric push rod is installed on the inner wall of the bottom of the base, and the output end of the second electric push rod is connected to the middle of the U-shaped toothed plate for transmission. The assembly formed by the first electric push rod and the limiting pressure plate can rotate and clearance at the front end of the capacitor shell under the transmission of the U-shaped toothed plate, the gears, and the second electric push rod.

[0015] A method for manufacturing a low-inductance DC pulse capacitor includes the following steps.

[0016] S1, Semi-finished capacitor assembly

[0017] The capacitor cores are connected in series and parallel through copper connecting pieces to form the capacitor body. The connected capacitor body is then installed in a clean and dry capacitor shell and the lead electrodes are connected to form a semi-finished capacitor. The top and bottom of the capacitor shell are pre-set with tapered blind holes and composite flow channels.

[0018] S2, Vacuum drying

[0019] Place the semi-finished capacitors into a vacuum drying oven, evacuate to below -0.095MPa, and dry at a temperature range of 80℃-85℃ for 2-6 hours to remove the moisture adsorbed inside the capacitor body and the capacitor shell. After drying, fill with dry nitrogen to atmospheric pressure and allow the semi-finished capacitors to cool naturally to room temperature.

[0020] S3, Rubber compounding and degassing treatment

[0021] Mix epoxy resin and curing agent according to the required ratio, stir evenly, and put the mixed adhesive into a vacuum degassing machine. Degas for 10-25 minutes at a pressure below -0.095MPa until no obvious bubbles float to the surface.

[0022] S4, Vacuum potting treatment

[0023] The base, bidirectional lead screw, brake servo motor and fixture mechanism are placed into the vacuum dispensing machine cavity for assembly. Then, the semi-finished capacitor is placed into the fixture mechanism for positioning and installation. After stabilization, the two composite plugs are respectively snapped into the conical blind hole at the top of the capacitor shell and the conical blind hole at the bottom of the capacitor shell for preliminary connection assembly. The flow guide valve tube is connected to the dispensing mechanism of the vacuum dispensing machine.

[0024] After the two composite plugs are initially snapped together and assembled, the brake servo motor is started, which drives the bidirectional lead screw to rotate synchronously. Then, the bidirectional lead screw meshes with the two U-shaped pressure plates, causing the two U-shaped pressure plates to move close to each other by a specified distance. During the movement, the two U-shaped pressure plates will press against their respective composite plugs, forcing the composite plugs to move by the same distance, thereby making the clearance space set in the two composite plugs communicate with the two composite flow channels respectively.

[0025] Close the internal space of the vacuum dispensing machine, start the vacuum pump installed inside the vacuum dispensing machine and evacuate the internal space of the vacuum dispensing machine to below -0.095MPa, and maintain this pressure for 5-10 minutes;

[0026] Maintain vacuum, close the third electric push rod which was originally in the open state, and enable the third electric push rod to automatically assemble the dispensing tube with the corresponding composite plug. Open the solenoid valve inside the guide valve tube, start the existing dispensing mechanism in the vacuum dispensing machine, and make it dispense glue through the dispensing tube. Control the dispensing speed so that the glue rising speed does not exceed 5mm / min. The glue enters the interior of the capacitor shell from the composite plug and composite flow channel set at the bottom of the capacitor shell and fills it from bottom to top. The air in the gap between the capacitor shell and the capacitor body is discharged from the composite flow channel and composite plug set at the top of the capacitor shell.

[0027] When the adhesive continuously overflows from the composite plug at the top of the capacitor casing, it indicates that the internal air between the capacitor casing and the capacitor body has been purged and the adhesive has been filled. At this point, the output of the existing dispensing mechanism in the vacuum dispensing machine should be stopped immediately.

[0028] S5, Sealing treatment

[0029] Restart the brake servo motor, which drives the bidirectional lead screw to rotate synchronously. Then, the bidirectional lead screw meshes with the two U-shaped pressure plates, causing the two U-shaped pressure plates to move closer together by a specified distance. During the movement, the two U-shaped pressure plates will press against their respective composite plugs, forcing the composite plugs to move by the same distance. This allows the two composite plugs to be fitted into their respective conical blind holes, and then to be misaligned and sealed with their respective composite flow channels.

[0030] S6, Vacuum settling

[0031] After sealing, continue to maintain a vacuum state and let it stand for 1-2 hours to allow the adhesive to flow naturally and for tiny air bubbles to rise and burst.

[0032] S7, Curing process

[0033] Remove the capacitor after it has been left to stand, place it in the curing oven, set the curing temperature and time according to the adhesive properties, use programmed temperature control for curing, and increase the temperature at a uniform rate.

[0034] S8, Defective Product Inspection

[0035] After curing, apply the rated voltage to the capacitor for 8-24 hours, and eliminate those with abnormal leakage current. Test the capacitance, loss tangent, equivalent series inductance, insulation resistance, and withstand voltage at room temperature to ensure that they meet the design requirements.

[0036] The present invention has the following beneficial effects:

[0037] 1. This low-inductance DC pulse capacitor, by opening conical blind holes and composite flow channels at the top and bottom of the capacitor shell, allows the two conical blind holes and two composite flow channels to cooperate in forming two glue injection channels. Subsequently, with the cooperation of two composite plugs, a glue injection mechanism and a fixture mechanism, the gap between the capacitor shell and the capacitor body can be filled with glue from bottom to top. Air can be discharged without passing through the glue layer, effectively avoiding the dead zone of air bubbles at the top and improving the processing quality.

[0038] 2. This low-inductance DC pulse capacitor features a bidirectional top-pressing mechanism consisting of a bidirectional lead screw, two U-shaped pressure plates, and a brake servo motor. When combined with the glue-filling mechanism, the two U-shaped pressure plates, driven by the bidirectional lead screw and the brake servo motor, can press down on the two composite plugs after glue filling, thereby causing the two composite plugs to be misaligned and sealed with their respective composite flow channels. The clearance space formed by the two conical blind holes will also be filled by the two composite plugs simultaneously. This not only satisfies the sealing treatment of the hole structure on the surface of the capacitor shell, but also avoids the problem of epoxy resin micro-cracks caused by the high temperature of hot melt welding in existing technologies.

[0039] 3. In the further combination of the composite plug and the corresponding conical blind hole and composite flow channel, the composite plug, in addition to directly filling and sealing the conical blind hole and composite flow channel with glue, has a reinforced external thread in its further modification. This allows the composite plug to first fill and seal the conical blind hole and then connect and seal with the thread of the conical blind hole, thus improving both sealing performance and structural connection strength.

[0040] 4. The manufacturing method of this low-inductance DC pulse capacitor involves dual-hole injection and the coordinated operation of two composite plugs. The injection method, with bottom injection and top venting, ensures that the adhesive completely fills the internal gaps. After curing, the adhesive itself forms an insulating seal, completely eliminating air gaps and significantly increasing the partial discharge initiation voltage. Secondly, the composite plugs can also be tightly connected to the shell through threads, forming a triple sealing mechanism of "filling-threading-adhesive"—the filling eliminates structural gaps, the threaded connection provides mechanical locking and pre-tightening force, and the adhesive fills the micro-interface and prevents loosening. The three work together to ensure long-term reliable sealing. Compared with hot melt welding, this method completely avoids the risk of microcracks caused by thermal stress. Attached Figure Description

[0041] Figure 1 This is a cross-sectional schematic diagram of the capacitor casing of the present invention;

[0042] Figure 2 This is a front view schematic diagram of the capacitor casing of the present invention;

[0043] Figure 3This is a three-dimensional schematic diagram of the capacitor casing of the present invention;

[0044] Figure 4 This is a top view of the capacitor casing of the present invention;

[0045] Figure 5 This is a right-side view of the structural positioning bracket of the present invention;

[0046] Figure 6 This is a three-dimensional schematic diagram of the composite plug of the present invention;

[0047] Figure 7 This is a three-dimensional schematic diagram of the bidirectional lead screw structure of the present invention;

[0048] Figure 8 For the present invention Figure 1 Enlarged view of point A in the middle;

[0049] Figure 9 For the present invention Figure 1 Enlarged view of point B in the middle;

[0050] Figure 10 This is an enlarged schematic diagram of the hollow plug tube in the structure of the present invention;

[0051] Figure 11 This is a schematic flowchart of the manufacturing method of the low-inductance DC pulse capacitor of the present invention.

[0052] In the diagram: 1. Capacitor casing; 2. Capacitor body; 3. Base; 4. Positioning bracket; 5. Limiting assembly; 51. Support cylinder; 52. First electric push rod; 53. Limiting pressure plate; 54. Gear; 55. U-shaped toothed plate; 56. Second electric push rod; 6. Conical blind hole; 7. Composite flow channel; 71. Circular groove; 72. Transition hole; 8. Composite plug; 81. Hollow plug cylinder; 82. Side flow hole; 83. First sealing ring; 84. Second sealing ring; 85. Reinforced external thread; 9. Bidirectional lead screw; 10. U-shaped pressure plate; 11. Brake servo motor; 12. Glue injection tube; 13. Flow guide valve tube; 14. Third electric push rod; 15. Auxiliary guide bracket; 16. Friction reduction roller. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] Please see Figure 1 and Figure 10A low-inductance DC pulse capacitor includes a capacitor housing 1 and a capacitor body 2 housed inside the capacitor housing 1. A filling space is provided between the capacitor housing 1 and the capacitor body 2. The top and bottom of the capacitor housing 1 are provided with conical blind holes 6 and composite flow channels 7, and adjacent conical blind holes 6 are connected to the composite flow channels 7. A composite plug 8 is nested inside the conical blind holes 6. A clearance space is provided in the middle of the composite plug 8, which is connected to the space of the composite flow channel 7. The composite flow channel 7 includes an annular groove 71 and several transition holes 72. The several transition holes 72 are arranged along the circumference of the annular groove 71, and the port of the transition hole 72 away from the annular groove 71 is connected to the internal space of the capacitor housing 1. In addition to forming a complete flow channel at a designated position on the capacitor housing 1 by using the annular groove 71 and the multiple transition holes 72, the curved structure also provides favorable conditions for the subsequent misalignment sealing of the corresponding composite plug 8.

[0055] The composite plug 8 includes a hollow plug cylinder 81, a first sealing ring 83, and a second sealing ring 84. The hollow plug cylinder 81 has a side flow hole 82 in the middle as a clearance space. The flow channel space formed by the hollow plug cylinder 81 and the side flow hole 82 can provide clearance conditions for subsequent air discharge or glue injection. The side flow hole 82 can communicate with the space of the annular groove 71. The first sealing ring 83 and the second sealing ring 84 are respectively fitted on the middle surface and the outer side of one end of the hollow plug cylinder 81. The bottom of the first sealing ring 83 is tightly engaged with the end space of the conical blind hole 6 near the capacitor body 2. After the hollow plug cylinder 81 is further displaced under pressure, the second sealing ring 84 can cover and close the open area of ​​the annular groove 71, so that the composite flow channel 7 is open when in use and closed when not in use.

[0056] Furthermore, a glue-filling mechanism is installed inside the composite plug 8 located at the bottom of the capacitor housing 1. The glue-filling mechanism includes a glue-filling tube 12, a flow-guiding valve tube 13, and a third electric push rod 14. One end of the glue-filling tube 12 is designed with a tapered structure and fitted with a buffer pad ring to reduce friction and collision between the glue-filling tube 12 and the corresponding composite plug 8 during the reciprocating fitting process, thereby extending the service life of the glue-filling tube 12. One end of the flow-guiding valve tube 13 is fitted on one side of the bottom of the glue-filling tube 12. The third electric push rod 14 is installed on the inner wall of the bottom of the base 3, and a linkage plate is installed between the output end of the third electric push rod 14 and the bottom of the glue-filling tube 12. This enables the glue-filling tube 12 to automatically separate from the corresponding composite plug 8, further improving the automation performance of the overall device and increasing work efficiency.

[0057] A base 3 is provided at the bottom of the capacitor housing 1, and a fixture mechanism for clamping and limiting the capacitor housing 1 is provided at the top of the base 3.

[0058] The fixture mechanism includes a positioning bracket 4 and two limiting components 5. The positioning bracket 4 is fixedly sleeved inside the base 3, and buffer grooves are opened on both sides of the bottom of the positioning bracket 4. Several anti-friction rollers 16 that can roll and contact the capacitor shell 1 on the ground are arranged in the buffer grooves. The multiple anti-friction rollers 16 can improve the smoothness of the displacement of the capacitor shell 1 during the positioning and assembly process inside the positioning bracket 4, further optimize the operating conditions, and also avoid friction of the capacitor shell 1 during the repositioning process inside the positioning bracket 4, thus avoiding damage to the surface of the capacitor shell 1.

[0059] The limiting component 5 includes a support cylinder 51, a first electric push rod 52, a limiting pressure plate 53, and a rotation clearance structure. One end of the support cylinder 51 is fitted with a bearing seat fixed to the top of the base 3 via a bearing assembly, and the other end of the support cylinder 51 is fitted with the housing of the first electric push rod 52. The output end of the first electric push rod 52 is connected to the middle of the limiting pressure plate 53 via a transmission connection. Under the transmission of the first electric push rod 52, the limiting pressure plate 53 can cooperate with the positioning bracket 4 to automatically clamp and limit the assembly formed by the capacitor housing 1 and the capacitor body 2, further improving the automatic use effect of the overall device.

[0060] The rotating clearance structure includes two gears 54, a U-shaped toothed plate 55, and a second electric push rod 56. The two gears 54 are respectively fitted on the outer side of one end of the two support cylinders 51 and then meshed with the two sides of the U-shaped toothed plate 55. The second electric push rod 56 is installed on the inner wall of the bottom of the base 3, and the output end of the second electric push rod 56 is connected to the middle of the U-shaped toothed plate 55 for transmission. The assembly formed by the first electric push rod 52 and the limiting pressure plate 53 can rotate and clearance at the front end of the capacitor shell 1 under the transmission of the U-shaped toothed plate 55, the gears 54, and the second electric push rod 56, providing automated clearance conditions for the subsequent processing and handling of the capacitor shell 1, and further improving the convenience of the overall device in the operation process.

[0061] The rear end of the base 3 is provided with a bidirectional lead screw 9 and a brake servo motor 11. Both ends of the bidirectional lead screw 9 are threaded with U-shaped pressure plates 10, and one end of the bidirectional lead screw 9 is connected to the output end of the brake servo motor 11 installed on the inner wall of the bottom of the base 3. The two U-shaped pressure plates 10 move close to each other under the combined transmission of the bidirectional lead screw 9 and the brake servo motor 11. During the movement of the two U-shaped pressure plates 10, they can press the two composite plugs 8 respectively, so that the two composite plugs 8 respectively close the two composite flow channels 7 in a staggered manner.

[0062] The outer sides of both ends of the bidirectional lead screw 9 are fitted with auxiliary guide brackets 15 that are fixed to the inner wall of the bottom of the base 3. The front end structure of the auxiliary guide brackets 15 is engaged with the middle of the two U-shaped pressure plates 10. The bidirectional lead screw 9 consists of a main rod and two lead screws with opposite conveying directions. One end of each lead screw is connected to both ends of the main rod. Nuts that can be threadedly connected to the lead screws are fixedly nested inside the two U-shaped pressure plates 10. The middle of the main rod is fitted with an auxiliary frame fixed to the top of the rear end of the base 3 through a bearing, which improves the stability of the continuous output rotation of the bidirectional lead screw 9.

[0063] The inner wall of the port of the conical blind hole 6 away from the capacitor body 2 is provided with an internal thread, and the surface of the other end of the hollow plug 81 is provided with a reinforced external thread 85 that can engage with the internal thread. The end of the other end of the hollow plug 81 is provided with an internal hexagonal groove. As a technical means to further expand the conditions and accelerate the processing efficiency, after the composite plug 8 is forced down for the second time by the U-shaped pressure plate 10 and the composite plug 8 performs misaligned sealing on the corresponding composite flow channel 7, the two composite plugs 8 can be immediately connected to their respective conical blind holes 6 by thread using a wrench. Thus, on the basis of glue sealing, mechanical meshing sealing is added, which can further improve the sealing effect of the conical blind hole 6 and the composite flow channel 7.

[0064] Please see Figure 1 and Figure 11 A method for manufacturing a low-inductance DC pulse capacitor includes the following steps.

[0065] S1, Semi-finished capacitor assembly

[0066] The capacitor cores are connected in series and parallel through copper connecting pieces to form the capacitor body 2. The connected capacitor body 2 is further installed in the clean and dry capacitor shell 1, and the lead electrodes are connected to form a semi-finished capacitor. The top and bottom of the capacitor shell 1 are pre-set with tapered blind holes 6 and composite flow channels 7.

[0067] S2, Vacuum drying

[0068] Place the semi-finished capacitor into a vacuum drying oven, evacuate to below -0.095MPa, and dry for 2-6 hours at a temperature range of 80℃-85℃ to remove the moisture adsorbed inside the capacitor body 2 and the capacitor shell 1. After drying, fill with dry nitrogen to normal pressure and allow the semi-finished capacitor to cool naturally to room temperature.

[0069] S3, Rubber compounding and degassing treatment

[0070] Mix epoxy resin and curing agent according to the required ratio, stir evenly, put the mixed adhesive into a vacuum degasser, degas at -0.095MPa for 10-25 minutes until no obvious bubbles float to the surface;

[0071] S4, Vacuum potting treatment

[0072] The base 3, bidirectional lead screw 9, brake servo motor 11, and fixture mechanism are placed into the vacuum dispensing machine cavity for assembly. Then, the semi-finished capacitor is placed into the fixture mechanism for positioning and installation. The detailed operation is as follows:

[0073] First, the capacitor housing 1 is fitted inside the positioning bracket 4 and connected to the inner wall of the positioning bracket 4, thereby initially positioning the capacitor housing 1. Then, the second electric push rod 56, which was originally in the open state, is closed. The output end of the second electric push rod 56 drives the corresponding U-shaped toothed plate 55 to move synchronously. Subsequently, the U-shaped toothed plate 55 synchronously meshes with the two gears 54, causing the two gears 54 to drive their respective support cylinder 51, the first electric push rod 52, and the limiting pressure plate 53 to rotate synchronously until the limiting pressure plate 53 is completely outside the front end of the capacitor housing 1. Then, the two first electric push rods 52, which were originally in the open state, are closed. The two first electric push rods 52 drive their respective corresponding limiting pressure plates 53 to move automatically until the two limiting pressure plates 53 press against the front end surface of the capacitor housing 1, thereby completing the positioning and clamping of the capacitor housing 1.

[0074] After stabilization, the two composite plugs 8 are respectively snapped into the conical blind hole 6 at the top and the conical blind hole 6 at the bottom of the capacitor housing 1 for preliminary connection and assembly, and the flow guide valve tube 13 is connected to the glue dispensing mechanism of the vacuum dispensing machine.

[0075] After the two composite plugs 8 are initially snapped together, the brake servo motor 11 is started, which drives the bidirectional lead screw 9 to rotate synchronously. The bidirectional lead screw 9 then engages with the two U-shaped pressure plates 10, causing the two U-shaped pressure plates 10 to move close together by a specified distance. During the movement, the two U-shaped pressure plates 10 will press against their respective composite plugs 8, forcing the composite plugs 8 to displace by the same distance. This allows the clearance spaces within the two composite plugs 8 to communicate with the two composite flow channels 7.

[0076] Further details are as follows: After the composite plug 8 is pressed by the U-shaped pressure plate 10, the hollow plug cylinder 81 inside the composite plug 8 drives the first sealing ring 83 and the second sealing ring 84 to move synchronously. After the displacement is completed, the side flow hole 82 set in the middle of the hollow plug cylinder 81 is in the open range of the inner ring structure of the conical blind hole 6, and then communicates with the conical blind hole 6. At the same time, one end of the first sealing ring 83 is forced into the conical space of the conical blind hole 6 for deformation and limitation, while the second sealing ring 84 synchronously seals the fitting gap between the hollow plug cylinder 81 and the composite plug 8.

[0077] Close the internal space of the vacuum dispensing machine, start the vacuum pump installed inside the vacuum dispensing machine and evacuate the internal space of the vacuum dispensing machine to below -0.095MPa, and maintain this pressure for 5-10 minutes;

[0078] Maintain vacuum, close the third electric push rod 14 which was originally in the open state, so that the third electric push rod 14 drives the glue injection tube 12 to automatically mount the corresponding composite plug 8, open the solenoid valve inside the flow guide valve tube 13, start the existing glue dispensing mechanism in the vacuum glue dispensing machine, so that it injects glue through the glue injection tube 12, control the dispensing speed, so that the glue liquid conveyed through the flow guide valve tube 13, glue injection tube 12, composite plug 8, conical blind hole 6 and the channel formed by the conical blind hole 6 does not exceed 5mm / min, the glue liquid enters into the interior of the capacitor shell 1 and fills from bottom to top, and at the same time, the air in the gap between the capacitor shell 1 and the capacitor body 2 is discharged from the channel space formed by the composite flow channel 7, conical blind hole 6 and composite plug 8 set at the top of the capacitor shell 1;

[0079] When the adhesive continuously overflows from the composite plug 8 set on the top of the capacitor casing 1, it indicates that the internal air between the capacitor casing 1 and the capacitor body 2 has been purged and the adhesive has been filled. At this time, the output of the existing dispensing mechanism in the vacuum dispensing machine should be stopped immediately.

[0080] S5, Sealing treatment

[0081] Restart the injection hose 12, which drives the bidirectional lead screw 9 to rotate synchronously. The bidirectional lead screw 9 then engages with the two U-shaped pressure plates 10, causing them to move closer together by a specified distance. During this movement, the two U-shaped pressure plates 10 press against their respective composite plugs 8, forcing them to displace by the same distance. This allows the two composite plugs 8 to fit into their respective tapered blind holes 6, and then to form a staggered seal with their respective composite flow channels 7. Further details are as follows:

[0082] After the composite plug 8 is pressed down again by the corresponding U-shaped pressure plate 10 and moved down as a whole, the first sealing ring 83 will be further embedded in the interior of the conical blind hole 6. At the same time, the second sealing ring 84 will replace the side flow hole 82 to cover and seal the open area of ​​the inner ring structure of the conical blind hole 6.

[0083] S6, Vacuum settling

[0084] After sealing, continue to maintain a vacuum state and let stand for 1-2 hours to allow the adhesive to flow naturally and the tiny air bubbles to rise and burst. At the same time, the two U-shaped pressure plates 10 maintain the pressure on their respective composite plugs 8, and the two limiting components 5 maintain the limiting clamping on the capacitor shell 1. Restart the third electric push rod 14, which will drive the glue injection tube 12 to automatically separate from the corresponding composite plug 8.

[0085] S7, Curing process

[0086] After the settling process is completed, the brake servo motor 11 is started, and the brake servo motor 11 drives the bidirectional lead screw 9 to reset and move the two U-shaped pressure plates 10. Similarly, the two first electric push rods 52 are activated, so that the two first electric push rods 52 drive their respective corresponding limit pressure plates 53 away from the capacitor shell 1. Then, the second electric push rod 56 is activated, so that the second electric push rod 56 drives the corresponding support cylinder 51, the first electric push rod 52 and the limit pressure plate 53 to rotate and move out of position through the meshing of the U-shaped toothed plate 55 and the two gears 54. The capacitor after settling is taken out and placed in the curing oven. The curing temperature and time are set according to the adhesive characteristics, and the temperature is controlled by a program, with the heating rate increasing at a uniform speed.

[0087] S8, Defective Product Inspection

[0088] After curing, apply the rated voltage to the capacitor for 8-24 hours, and eliminate those with abnormal leakage current. Test the capacitance, loss tangent, equivalent series inductance, insulation resistance, and withstand voltage at room temperature to ensure that they meet the design requirements.

[0089] Furthermore, in the S5 and sealing process, the composite plug 8 is adapted to different processing conditions after use;

[0090] For example, if the composite plug 8 needs to be completely nested into the corresponding conical blind hole 6, then the downward movement distance of the U-shaped pressure plate 10 needs to be increased during the secondary pressing transmission of the composite plug 8 by the U-shaped pressure plate 10.

[0091] For example, to further improve the connection strength and sealing effect between the composite plug 8 and the conical blind hole 6, after the vacuum potting process in S4, the internal space of the vacuum potting machine is opened, and the existing handle is used to engage with the internal hexagonal groove in the composite plug 8 and screwed until the reinforcing external thread 85 in the composite plug 8 is fully engaged with the corresponding internal thread in the conical blind hole 6. At the same time, the composite plug 8 can be fully fitted inside the conical blind hole 6 and further improve the sealing effect and connection strength with the conical blind hole 6 by mechanical locking.

[0092] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Moreover, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0093] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low-inductance DC pulse capacitor, comprising a capacitor housing (1) and a capacitor body (2) fitted inside the capacitor housing (1), wherein a filling space is provided between the capacitor housing (1) and the capacitor body (2), characterized in that: The capacitor housing (1) has conical blind holes (6) and composite flow channels (7) at its top and bottom. The adjacent conical blind holes (6) are connected to the composite flow channels (7). The conical blind holes (6) are nested inside the conical blind holes (6). The middle part of the composite plug (8) is provided with a clearance space that can communicate with the composite flow channels (7). The composite plug (8) at the bottom of the capacitor housing (1) is fitted with a potting mechanism. The bottom of the capacitor housing (1) is provided with a base (3). The top of the base (3) is provided with a fixture mechanism for clamping and limiting the capacitor housing (1). The rear end of the base (3) is provided with a bidirectional lead screw (9) and a brake servo motor (11). Both ends of the bidirectional lead screw (9) are threaded with U-shaped pressure plates (10), and one end of the bidirectional lead screw (9) is connected to the output end of the brake servo motor (11) installed on the inner wall of the bottom of the base (3). The two U-shaped pressure plates (10) move close to each other under the combined transmission of the bidirectional lead screw (9) and the brake servo motor (11). During the movement of the two U-shaped pressure plates (10), they can press the two composite plugs (8) respectively, so that the two composite plugs (8) respectively close the two composite channels (7).

2. The low-inductance DC pulse capacitor according to claim 1, characterized in that: The composite flow channel (7) includes an annular groove (71) and several transition holes (72), and the several transition holes (72) are arranged along the circumference of the annular groove (71), and the port of the transition hole (72) away from the annular groove (71) communicates with the internal space of the capacitor shell (1).

3. The low-inductance DC pulse capacitor according to claim 1, characterized in that: The composite plug (8) includes a hollow plug cylinder (81), a first sealing ring (83) and a second sealing ring (84). The hollow plug cylinder (81) has a side flow hole (82) in the middle as a clearance space, and the side flow hole (82) can communicate with the space of the annular groove (71). The first sealing ring (83) and the second sealing ring (84) are respectively fitted on the middle surface and the outer side of one end of the hollow plug cylinder (81). The bottom of the first sealing ring (83) is tightly engaged with the end space of the conical blind hole (6) near the capacitor body (2). After the hollow plug cylinder (81) is further displaced under pressure, the second sealing ring (84) can cover and seal the open area of ​​the annular groove (71).

4. A low-inductance DC pulse capacitor according to claim 3, characterized in that: The inner wall of the tapered blind hole (6) away from the capacitor body (2) is provided with an internal thread, and the surface of the other end of the hollow plug (81) is provided with a reinforced external thread (85) that can engage with the internal thread, and the end of the other end of the hollow plug (81) is provided with an internal hexagonal groove.

5. A low-inductance DC pulse capacitor according to claim 1, characterized in that: The outer sides of both ends of the bidirectional lead screw (9) are fitted with auxiliary guide brackets (15) that are fixed to the inner wall of the bottom of the base (3). The front end structure of the auxiliary guide bracket (15) is engaged with the middle of the two U-shaped pressure plates (10). The bidirectional lead screw (9) consists of a main rod and two lead screws with opposite conveying directions. One end of the two lead screws is connected to the two ends of the main rod respectively. The two U-shaped pressure plates (10) are both fixedly nested with nuts that can be threadedly connected to the lead screws. The middle of the main rod is fitted with an auxiliary frame fixed to the top of the rear end of the base (3) through a bearing.

6. A low-inductance DC pulse capacitor according to claim 1, characterized in that: The glue dispensing mechanism includes a glue dispensing tube (12), a flow guide valve tube (13), and a third electric push rod (14). One end of the glue dispensing tube (12) is set with a tapered structure and fitted with a buffer pad ring. One end of the flow guide valve tube (13) is fitted on one side of the bottom of the glue dispensing tube (12). The third electric push rod (14) is installed on the inner wall of the bottom of the base (3), and a linkage plate is installed between the output end of the third electric push rod (14) and the bottom of the glue dispensing tube (12).

7. A low-inductance DC pulse capacitor according to claim 1, characterized in that: The fixture mechanism includes a positioning bracket (4) and two limiting components (5). The positioning bracket (4) is fixedly sleeved inside the base (3), and buffer grooves are opened on both sides of the bottom of the positioning bracket (4). Several friction-reducing rollers (16) that can roll and contact the capacitor shell (1) on the ground are arranged in the buffer grooves.

8. A low-inductance DC pulse capacitor according to claim 7, characterized in that: The limiting component (5) includes a support cylinder (51), a first electric push rod (52), a limiting pressure plate (53), and a rotation clearance structure. One end of the support cylinder (51) is fitted with a bearing seat fixed to the top of the base (3) through a bearing sleeve, and the other end of the support cylinder (51) is fitted with the housing of the first electric push rod (52). The output end of the first electric push rod (52) is connected to the middle of the limiting pressure plate (53) through transmission. Under the transmission of the first electric push rod (52), the limiting pressure plate (53) can cooperate with the positioning bracket (4) to automatically clamp and limit the assembly formed by the capacitor shell (1) and the capacitor body (2).

9. A low-inductance DC pulse capacitor according to claim 8, characterized in that: The rotational clearance structure includes two gears (54), a U-shaped toothed plate (55), and a second electric push rod (56). The two gears (54) are respectively fitted on the outer side of one end of the two support cylinders (51) and then meshed with the two sides of the U-shaped toothed plate (55). The second electric push rod (56) is installed on the inner wall of the bottom of the base (3), and the output end of the second electric push rod (56) is connected to the middle of the U-shaped toothed plate (55) for transmission. The assembly formed by the first electric push rod (52) and the limiting pressure plate (53) can rotate and clearance at the front end of the capacitor shell (1) under the transmission of the U-shaped toothed plate (55), the gears (54), and the second electric push rod (56).

10. A method for manufacturing a low-inductance DC pulse capacitor as described in claim 6, characterized in that, Includes the following operating steps S1, Semi-finished capacitor assembly The capacitor cores are connected in series and parallel through copper connecting pieces to form a capacitor body (2). The connected capacitor body (2) is further installed in a clean and dry capacitor shell (1) and the lead electrodes are connected to form a semi-finished capacitor. The top and bottom of the capacitor shell (1) are pre-set with tapered blind holes (6) and composite flow channels (7). S2, Vacuum drying Place the semi-finished capacitor into a vacuum drying oven, evacuate to below -0.095MPa, and dry for 2-6 hours at a temperature range of 80℃-85℃ to remove the moisture adsorbed inside the capacitor body (2) and inside the capacitor shell (1). After drying, fill with dry nitrogen to normal pressure and allow the semi-finished capacitor to cool naturally to room temperature. S3, Rubber compounding and degassing treatment Mix epoxy resin and curing agent according to the required ratio, stir evenly, and put the mixed adhesive into a vacuum degassing machine. Degas for 10-25 minutes at a pressure below -0.095MPa until no obvious bubbles float to the surface. S4, Vacuum potting treatment The base (3), bidirectional lead screw (9), brake servo motor (11) and fixture mechanism are placed into the vacuum dispensing machine cavity for assembly. Then, the semi-finished capacitor is placed into the fixture mechanism for positioning and installation. After stabilization, the two composite plugs (8) are respectively snapped into the conical blind hole (6) set at the top of the capacitor shell (1) and the conical blind hole (6) set at the bottom of the capacitor shell (1) for preliminary connection assembly. The flow guide valve tube (13) is connected to the dispensing mechanism of the vacuum dispensing machine. After the two composite plugs (8) are initially snapped together, the brake servo motor (11) is started. The brake servo motor (11) drives the bidirectional screw (9) to rotate synchronously. Then, the bidirectional screw (9) meshes with the two U-shaped pressure plates (10) respectively, so that the two U-shaped pressure plates (10) move close to each other by a specified distance. During the movement, the two U-shaped pressure plates (10) will press against their respective composite plugs (8), forcing the composite plugs (8) to move by the same distance, so that the clearance space set in the two composite plugs (8) is connected to the two composite flow channels (7) respectively. Close the internal space of the vacuum dispensing machine, start the vacuum pump installed inside the vacuum dispensing machine and evacuate the internal space of the vacuum dispensing machine to below -0.095MPa, and maintain this pressure for 5-10 minutes; Maintain vacuum, close the third electric push rod (14) which was originally in the open state, so that the third electric push rod (14) drives the glue injection tube (12) and the corresponding composite plug (8) to automatically fit together, open the solenoid valve inside the guide valve tube (13), start the existing glue dispensing mechanism in the vacuum glue dispensing machine, so that it injects glue through the glue injection tube (12), control the dispensing speed, so that the glue rise speed does not exceed 5mm / min, the glue enters the interior of the capacitor shell (1) from the bottom of the capacitor shell (1) through the composite plug (8) and composite flow channel (7) and fills from bottom to top, and the air in the gap between the capacitor shell (1) and the capacitor body (2) is discharged from the composite flow channel (7) and composite plug (8) set at the top of the capacitor shell (1); When the adhesive continuously overflows from the composite plug (8) set on the top of the capacitor casing (1), it indicates that the internal air between the capacitor casing (1) and the capacitor body (2) has been purged and the adhesive has been filled. At this time, the output of the existing dispensing mechanism in the vacuum dispensing machine should be stopped immediately. S5, Sealing treatment The brake servo motor (11) is restarted, and the brake servo motor (11) drives the bidirectional screw (9) to rotate synchronously. Then, the bidirectional screw (9) meshes with the two U-shaped pressure plates (10) respectively, so that the two U-shaped pressure plates (10) move close to each other again by a specified distance. During the movement, the two U-shaped pressure plates (10) will press against their respective composite plugs (8), forcing the composite plugs (8) to move by the same distance, so that the two composite plugs (8) are further fitted with their respective conical blind holes (6), and then misaligned and sealed with their respective composite flow channels (7). S6, Vacuum settling After sealing, continue to maintain a vacuum state and let it stand for 1-2 hours to allow the adhesive to flow naturally and for tiny air bubbles to rise and burst. S7, Curing process Remove the capacitor after it has been left to stand, place it in the curing oven, set the curing temperature and time according to the adhesive properties, use programmed temperature control for curing, and increase the temperature at a uniform rate. S8, Defective Product Inspection After curing, apply the rated voltage to the capacitor for 8-24 hours, and eliminate those with abnormal leakage current. Test the capacitance, loss tangent, equivalent series inductance, insulation resistance, and withstand voltage at room temperature to ensure that they meet the design requirements.

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