A needle seal structure and a manufacturing method thereof

Abstract

The embodiments of the present disclosure disclose a sealing needle structure and a manufacturing method thereof, and relate to the technical field of capacitors, but are not limited thereto. The sealing needle structure is formed by two eccentric circular arcs with different radii, which form a gradual extrusion profile. The metal of the aluminum shell port can sequentially pass through the second circular arc and the first circular arc and continuously and uniformly flow plastically, effectively improving the quality of the edge curl forming, avoiding flat shoulder defects and edge curl damage, and because the first circular platform is located at the end of the sealing needle structure, after the edge curl forming is completed, the circumferential outer side of the first circular platform finally presses the curled aluminum shell edge to the surface of the cover plate, forming a circumferential point-by-point gradual and uniform surface contact and pressing seal between the aluminum shell and the cover plate, thereby effectively improving the irregularity of the aluminum shell and the cover plate, improving the sealing consistency and reliability of the sealing structure, and especially greatly improving the quality and service life of the Snap-in series aluminum electrolytic capacitor.

Description

Technical Field

[0001] This disclosure relates to, but is not limited to, the field of capacitor technology, and in particular to a sealing pin structure and its manufacturing method. Background Technology

[0002] Aluminum electrolytic capacitors are crucial core components in power electronics, new energy, and industrial control equipment. Their sealing process directly affects the capacitor's insulation, sealing performance, service life, and reliability. Aluminum electrolytic capacitors typically employ a high-speed spinning sealing process, where the sealing machine's sleeve and sealing needle roll and squeeze at high speed to press and seal the aluminum shell edge against the cover plate. However, problems such as rough aluminum shell edges, irregular fit between the aluminum shell and cover plate, flat shoulder defects, and failure of the rounded edge forming process can easily occur during production. These issues can lead to quality problems such as electrolyte leakage, excessive leakage current, and high-temperature failure. Summary of the Invention

[0003] The purpose of this disclosure is to propose a sealing pin structure and its manufacturing method, which aims to solve problems such as rough aluminum shell edges, irregular bonding between aluminum shell and cover plate, flat shoulder defects, and failure of arc-shaped edge forming that are prone to occur in the existing production process.

[0004] A first aspect of this disclosure provides a sealing pin structure, comprising: The first circular platform; and A second circular platform is connected to the first circular platform via a connecting segment; The connecting segment has a concave surface on its circumferential outer side. The concave surface connects the first circular platform and the second circular platform and forms an annular groove between the first circular platform and the second circular platform. The first circular platform, the second circular platform and the concave surface are coaxially arranged. The contour line of the concave surface on the cross section passing through the axis of the first circular platform includes a first arc and a second arc connected in sequence. The first arc is set close to the first circular platform, and the second arc is set close to the second circular platform. The center of the first arc and the center of the second arc are eccentrically set in a direction perpendicular to the axis of the first circular platform. The radius of the first arc is smaller than the radius of the second arc.

[0005] According to the sealing pin structure provided in this embodiment, a gradual extrusion surface is formed by two eccentrically arranged arcs of different radii. This allows the aluminum shell end metal to pass through the second and first arcs sequentially and undergo continuous and uniform plastic flow, effectively improving the edge forming quality and avoiding flat shoulder defects and edge breakage. Furthermore, since the first circular platform is located at the end of the sealing pin structure, after the edge forming is completed, the circumferential outer side of the first circular platform finally presses the edge of the rolled aluminum shell against the surface of the cover plate, forming a circumferential, point-by-point, gradual, and uniform surface contact and sealing between the aluminum shell and the cover plate. This effectively improves the problem of irregular fit between the aluminum shell and the cover plate, enhances the sealing consistency and reliability of the sealing structure, and significantly improves the quality and lifespan of Snap-in series aluminum electrolytic capacitors.

[0006] In some embodiments of the sealing pin structure, the distance between the first circular platform and the second circular platform along the axial direction of the first circular platform is equal to the sum of the radius of the first arc and the radius of the second arc.

[0007] In some embodiments of the sealing pin structure, the radius of the first arc is 0.90 mm to 1.05 mm; The radius of the second arc is 0.95 mm to 1.15 mm.

[0008] In some embodiments of the sealing pin structure, the vertical distance between the maximum radial dimension position of the first circular platform and the minimum radial dimension position of the connecting segment along the direction perpendicular to the axial direction of the first circular platform is greater than the radius of the first arc and less than the radius of the second arc.

[0009] In some embodiments of the sealing needle structure, the first circular platform includes a circumferential surface and a first plane and a second plane disposed opposite to each other along the axial direction of the first circular platform. The circumferential surface is a cylindrical surface. The first plane is positioned away from the connecting segment, and an arc transition is formed between the first plane and the circumferential surface; The second plane is connected to the connecting segment, and there is an arc transition between the second plane and the circumferential surface.

[0010] In some embodiments of the sealing pin structure, the axial dimension of the first circular platform is 0.6 mm to 0.9 mm; The maximum diameter of the first circular platform is 8 mm.

[0011] In some embodiments of the sealing pin structure, the second circular platform has a conical surface on its circumferential outer side, the conical surface being coaxially arranged with the concave surface, and the conical surface being able to form a small end face on the side of the second circular platform connected to the connecting segment.

[0012] In some embodiments of the sealing needle structure, the small end face is a plane perpendicular to the axial direction of the first circular platform; The intersection of the second arc and the second circular platform is located on the small end face, and the intersection of the second arc and the second circular platform is spaced apart from the intersection of the small end face and the conical surface.

[0013] In some embodiments of the sealing needle structure, the second circular platform is also connected to the connecting part via a third circular platform; The third circular platform and the connecting portion are coaxially arranged with the concave surface; The radial dimension of the third circular platform is the same as the radial dimension of the small end face.

[0014] A second aspect of this disclosure provides a method for manufacturing a sealing pin structure, comprising: Preparation of sealing needle matrix; A hard ceramic layer is formed on the outside of the sealing needle substrate to obtain the sealing needle structure as described above.

[0015] According to the manufacturing method of the sealing pin structure provided in the embodiments of this disclosure, by forming a hard ceramic layer on the substrate surface, the surface hardness, wear resistance and anti-aluminum adhesion properties of the sealing pin can be significantly improved, the service life of the sealing pin can be extended, and the forming quality of the aluminum shell surface during the sealing process can be improved.

[0016] Other features and advantages of this disclosure will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the disclosure. Other advantages of this disclosure may be realized and obtained by means of the methods described in the description and the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] in: Figure 1 This is a schematic diagram of the sealing needle structure in an embodiment of this disclosure; Figure 2 for Figure 1 Sectional view along line AA; Figure 3 for Figure 2 Enlarged structural diagram of section B in the middle; Figure 4 This is a schematic diagram showing the contact between the sealing pin structure and the aluminum shell in an embodiment of this disclosure; Figure 5 This is a photograph of the sealing pin structure in contact with the aluminum shell in an embodiment of this disclosure; Figure 6 This is a flowchart of a method for manufacturing a sealing pin structure according to an embodiment of this disclosure.

[0019] Explanation of icon numbers: 100. First circular platform; 110. Circumferential surface; 120. First plane; 130. Second plane; 200. Connecting section; 210. Concave surface; 211. First arc; 212. Second arc; 300. Second circular platform; 310. Conical surface; 320. Small end face; 330. Large end face; 340. Annular surface; 400. Third circular platform; 500. Connecting part; 20. Aluminum shell; 21. Indentation; 30. Cover plate. Detailed Implementation

[0020] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0021] This disclosure provides a sealing pin structure, which includes a first circular platform, a second circular platform, and a connecting segment connecting the first and second circular platforms. The connecting segment has a concave surface on its outer circumferential side. The contour line of the concave surface on the cross section passing through the axis of the first circular platform includes a first arc and a second arc connected in sequence. The center of the first arc and the center of the second arc are eccentrically arranged in a direction perpendicular to the axis of the first circular platform, and the radius of the first arc is smaller than the radius of the second arc. This sealing pin structure uses two eccentrically positioned arcs of different radii to form a gradual extrusion profile. This allows the metal at the aluminum shell end to pass through the second and first arcs sequentially, resulting in continuous and uniform plastic flow. This effectively improves the quality of the rolled edge forming, avoiding flat shoulder defects and edge breakage. Furthermore, since the first circular platform is located at the end of the sealing pin structure, after the rolled edge forming is completed, the outer circumferential direction of the first circular platform presses the rolled edge of the aluminum shell firmly against the cover plate surface. This creates a circumferential, point-to-point, gradual, and uniform surface contact and sealing between the aluminum shell and the cover plate, effectively improving the problem of irregular fit between the aluminum shell and the cover plate. This enhances the sealing consistency and reliability of the sealing structure, and significantly improves the quality and lifespan of Snap-in series aluminum electrolytic capacitors.

[0022] This disclosure also provides a method for manufacturing a sealing pin structure. The method includes preparing a sealing pin substrate and forming a hard ceramic layer on the outer side of the sealing pin substrate to obtain the sealing pin structure. By forming a hard ceramic layer on the substrate surface, the surface hardness, wear resistance, and anti-aluminum adhesion properties of the sealing pin structure can be significantly improved, extending the service life of the sealing pin structure and improving the forming quality of the aluminum shell surface during the sealing process.

[0023] Figure 1 This is a schematic diagram of the sealing needle structure in an embodiment of this disclosure. Figure 2 for Figure 1 Sectional view along the AA direction. Figure 3 for Figure 2 Enlarged structural diagram of section B. Figure 4 This is a schematic diagram showing the contact between the sealing pin structure and the aluminum shell in an embodiment of this disclosure. Figure 5 This is a photograph of the sealing pin structure in contact with the aluminum shell in an embodiment of this disclosure; like Figure 1 and Figure 2 As shown in the figure, this disclosure provides a sealing pin structure, which includes a first circular platform 100 and a second circular platform 300. The second circular platform 300 is connected to the first circular platform 100 via a connecting segment 200.

[0024] The connecting segment 200 has a concave surface 210 on its outer circumferential side. This concave surface 210 connects the first circular platform 100 and the second circular platform 300, forming an annular groove between them. The first circular platform 100, the second circular platform 300, and the concave surface 210 are coaxially arranged, meaning the axes of the first circular platform 100, the second circular platform 300, and the concave surface 210 coincide.

[0025] like Figure 2 and Figure 3 As shown, the contour line of the concave surface 210 on the cross section passing through the axis of the first circular platform 100 (the axis of the first circular platform 100 is entirely located in this cross section) includes a first arc 211 and a second arc 212 connected in sequence. The first arc 211 is located close to the first circular platform 100, and the second arc 212 is located close to the second circular platform 300. The centers of the first arc 211 and the second arc 212 are eccentrically positioned in a direction perpendicular to the axis of the first circular platform 100, that is, the centers of the first arc 211 and the second arc 212 are offset from each other in the radial direction, and the radius R0 of the first arc 211 is smaller than the radius R1 of the second arc 212.

[0026] like Figure 4 and Figure 5 As shown, during the sealing process, the aluminum shell 20 passes sequentially through the second arc 212 and the first arc 211, and is pressed onto the cover plate 30 by the outer circumferential direction of the first circular platform 100. Since the radius R0 of the first arc 211 is smaller than the radius R1 of the second arc 212, and the centers of the two arcs are offset, the metal at the end of the aluminum shell 20 undergoes pre-extrusion deformation under the high-speed rolling extrusion of the sealing needle structure, first passing through the larger radius second arc 212 for pre-extrusion deformation, and then through the smaller radius first arc 211 for finishing, forming a two-stage gradual extrusion effect. This structural design avoids the problems of uneven metal plastic deformation rate and inconsistent circumferential force caused by instantaneous rigid extrusion in traditional single-arc sealing needle structures, thus effectively suppressing flat shoulder defects and edge curling damage.

[0027] In some embodiments, the radius R0 of the first arc 211 is 0.90 mm to 1.05 mm, and the radius R1 of the second arc 212 is 0.95 mm to 1.15 mm. For example, R0 can be 0.90 mm, 0.95 mm, 1.00 mm, or 1.05 mm, and R1 can be 0.95 mm, 1.00 mm, 1.05 mm, 1.10 mm, or 1.15 mm, etc. By setting the radii of the two arcs within the above ranges, the smoothness of the sealing edge can be ensured, while simultaneously meeting the sealing forming requirements of aluminum shells 20 of different specifications. The small difference between the radius R0 of the first arc 211 and the radius R1 of the second arc 212 allows the metal at the port of the aluminum shell 20 to flow smoothly and continuously when transitioning from the second arc 212 to the first arc 211, avoiding stress concentration or local wrinkles caused by abrupt changes in the surface.

[0028] It should be noted that the rolled edge profile of traditional sealing pin structures typically adopts a single arc design, resulting in a relatively simple metal plastic flow path. This makes it difficult to simultaneously meet the requirements of both pre-forming and finishing stages, easily leading to insufficient rolled edge forming or excessive extrusion. In contrast, the embodiment disclosed in this paper employs a structure with two arcs of different radii, eccentrically positioned. This allows the metal at the aluminum shell 20 port to first undergo pre-bending through the larger radius region of the second arc 212 during the sealing process, and then final shaping through the smaller radius region of the first arc 211. In other words, the metal at the aluminum shell 20 port undergoes three angular changes—displacement, flow guidance, and progressive extrusion—resulting in a more rational metal flow path and a smoother, more uniform rolled edge profile after forming.

[0029] In some embodiments, such as Figure 3 As shown, the distance H between the first circular platform 100 and the second circular platform 300 along the axial direction of the first circular platform 100 is equal to the sum of the radius R0 of the first arc 211 and the radius R1 of the second arc 212, i.e., H = R0 + R1. Therefore, the first arc 211 and the second arc 212 can be tangentially connected to the first circular platform 100 and the second circular platform 300 respectively, allowing the metal at the port of the aluminum shell 20 to move more smoothly in and out of the annular groove.

[0030] In some embodiments, the perpendicular distance D1 between the position of the maximum radial dimension of the first circular platform 100 and the position of the minimum radial dimension of the connecting section 200 (i.e., the joint of the first arc 211 and the second arc 212) along the direction perpendicular to the axial direction of the first circular platform 100 is greater than the radius R0 of the first arc 211 and less than the radius R1 of the second arc 212, that is, R0<D1<R1. Illustratively, D1 is 0.92mm to 1.09mm. By setting D1 between R0 and R1, the size of the first circular platform 100 protruding from the connecting section 200 is moderate, which ensures that a circumferential point-by-point progressive uniform surface contact compression seal is formed between the aluminum case 20 and the cover plate 30, and at the same time avoids scratching the aluminum case 20 and / or the cover plate 30.

[0031] Please continue to refer to Figure 1 and Figure 2 , the first circular platform 100 comprises a circumferential surface 110, a first plane 120 and a second plane 130 which are oppositely arranged along the axial direction of the first circular platform 100. The circumferential surface 110 is a cylindrical surface, the first plane 120 is arranged away from the connecting section 200, and the second plane 130 is connected with the connecting section 200. An arc transition is formed between the first plane 120 and the circumferential surface 110, and an arc transition is formed between the second plane 130 and the circumferential surface 110.

[0032] In some embodiments, the radius of the arc transition between the first plane 120 and the circumferential surface 110 is 0.20mm to 0.25mm, and the radius of the arc transition between the second plane 130 and the circumferential surface 110 is 0.20mm to 0.25mm. Forming arc transitions between the first plane 120, the second plane 130 and the circumferential surface 110 can prevent sharp edges from scratching the surface of the aluminum case 20 during the sealing process, and at the same time help the metal at the port of the aluminum case 20 to smoothly fit the surface of the cover plate 30 in the final compaction stage, and can form a raised structure on both sides of the indentation 21 of the aluminum case 20, which increases the connection area between the aluminum case 20 and the rubber sealing layer of the cover plate 30, and improves the fitting stability between the aluminum case 20 and the cover plate 30.

[0033] In some embodiments, the axial dimension W1 of the first circular platform 100 is 0.6 mm to 0.9 mm. Exemplarily, W1 can be 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm, etc. The maximum diameter D3 of the first circular platform 100 (i.e., the diameter of the circumferential surface 110) is 8 mm. The first circular platform 100 is configured such that after the sealing pin structure completes the edge-rolling process, it can press the edge of the aluminum shell 20 onto the capacitor cover plate 30 through the circumferential surface 110, forming an annular indentation 21. This indentation 21 is a deliberately designed process mark; the presence of indentation 21 indicates that the sealing pressure is qualified. Operators can visually determine whether this process is normal without the need for additional pressure testing instruments, thereby reducing testing costs and improving production efficiency.

[0034] Furthermore, the width W1 of the first circular platform 100 is 0.6mm to 0.9mm, and its maximum diameter is 8mm. This allows the sealing pin structure of this embodiment to be applicable to the sealing process of aluminum electrolytic capacitor products with different diameters ranging from φ22 to φ42. In other words, a single sealing pin structure can cover the sealing requirements of products with diameters from φ22 to φ42, eliminating the need to change the sealing pin structure for different product specifications. This significantly improves the flexibility of the production line and the utilization rate of equipment. Furthermore, by combining the radius of the arc transition between the first plane 120 and the circumferential surface 110, and the radius of the arc transition between the second plane 130 and the circumferential surface 110, a certain span is ensured for the circumferential surface 110, ensuring a flat bottom corresponding to the indentation 21, further enhancing the sealing effect.

[0035] In some embodiments, the minimum diameter D2 of the connecting segment 200 is 5.82 mm. The vertical distance L1 between the first plane 120 and the location of the minimum radial dimension of the connecting segment 200 (i.e., the minimum diameter of the concave surface 210) along the axial direction of the first circular platform 100 is 1.65 mm.

[0036] Please continue to refer to this. Figures 1 to 3The second circular platform 300 has a conical surface 310 on its outer circumferential side, which is coaxially arranged with the concave surface 210. The conical surface 310 forms a small end face 320 on one side of the connecting section 200 of the second circular platform 300. The small end face 320 is a plane perpendicular to the axial direction of the first circular platform 100. The intersection of the second arc 212 and the second circular platform 300 is located at the small end face 320, meaning the end of the second arc 212 extends to the small end face 320. The intersection of the second arc 212 and the second circular platform 300 is spaced apart from the intersection of the small end face 320 and the conical surface 310, with a spacing of 0.42 mm to 0.46 mm, thus exposing part of the small end face 320 outside the connecting section 200, forming an annular platform. The annular platform primarily serves as a load-bearing surface, pressing down on the rolled edge of the aluminum shell 20 to provide stable axial pressure. This annular platform is not a sharp corner, but rather a plane with a finite width. It distributes pressure evenly across the rolled edge of the aluminum shell 20 through surface contact rather than line contact. The annular platform supports the already partially bent rolled edge of the aluminum shell 20, pressing it to a set height and controlling the axial dimensions of the seal. Without this annular platform, pressure would concentrate on a single edge, creating indentations 21 on the aluminum shell 20, and potentially even producing localized sharp corners and flat shoulders.

[0037] In some embodiments, the diameter D4 of the small end face 320 is 9 mm. The conical surface 310 is provided so that the second circular platform 300 forms a conical transition structure on the side near the connecting section 200. When the sealing needle structure is in high-speed rotation extrusion, if the main body of the aluminum shell 20 tilts slightly, the conical surface 310 can straighten the main body of the aluminum shell 20. In addition, the conical surface 310 will not damage the aluminum shell 20 during high-speed rotation extrusion and removes burrs on the aluminum shell 20.

[0038] In some embodiments, please continue reading Figure 1 and Figure 2 The second circular platform 300 also includes a large end face 330 disposed opposite to the small end face 320 along the axial direction of the first circular platform 100, and the large end face 330 is parallel to the small end face 320. The second circular platform 300 also has an annular surface 340 located between the conical surface 310 and the large end face 330 on its circumferential outer side. The diameter D5 of the large end face 330 is 15 mm, and the axial dimension W2 of the second circular platform 300 is 2.5 mm. Thus, the arrangement of the large end face 330 and the annular surface 340 increases the overall thickness of the second circular platform 300, improving its structural strength.

[0039] In some embodiments, the second circular platform 300 is also connected to the connecting portion 500 via a third circular platform 400. The third circular platform 400 and the connecting portion 500 are coaxially arranged with the concave surface 210. The radial dimension of the third circular platform 400 is the same as the radial dimension of the small end face 320, that is, the maximum diameter of the third circular platform 400 is also 9 mm. The axial dimension W3 of the third circular platform 400 is 1 mm. The connecting portion 500 is cylindrical, and the maximum diameter D6 of the connecting portion 500 is 6 mm. The connecting portion 500 does not directly participate in the edge rolling of the aluminum shell 20. It is the main structure of the sealing needle structure, playing the roles of positioning, support, and pressure transmission, ensuring the rigidity of the sealing needle structure itself, and preventing deformation and vibration under pressure. The connecting portion 500 is configured to connect with the drive structure that drives the sealing needle structure to rotate. The total axial dimension L3 of the sealing needle structure is 32 mm.

[0040] In some embodiments, the vertical distance L4 between the side of the third circular platform 400 away from the second circular platform 300 and the position of the minimum radial dimension of the connecting segment 200 along the axial direction of the first circular platform 100 is 4.65 mm. The distance L2 between the first plane 120 and the side of the third circular platform 400 away from the second circular platform 300 along the axial direction of the first circular platform 100 is 6.3 mm.

[0041] In some embodiments, a circular arc transition with a radius of 0.25 mm is formed between the large end face 330 and the annular face 340. A circular arc transition with a radius of 0.25 mm is also formed between the circumferential outer side of the third circular platform 400 and the side of the third circular platform 400 opposite to the second circular platform 300. This circular arc transition avoids stress concentration and improves the structural strength and fatigue resistance of the sealing pin structure.

[0042] The sealing pin structure of this embodiment features an eccentrically positioned large and small arc structure between the first circular platform 100 and the second circular platform 300 at the head of the sealing pin structure. The radius R0 of the first arc 211 (small ring) ranges from 0.90 mm to 1.05 mm, and the radius R1 of the second arc 212 (large ring) ranges from 0.95 mm to 1.15 mm. This is crucial for ensuring a smooth sealing edge. Traditional sealing pin structures typically use a single-radius arc for edge forming, resulting in an edge profile equivalent to a semi-circular structure (while this embodiment uses a combination of two quarter-circular arc structures with different radii). This only achieves a single level of bending deformation and cannot meet the process requirements for maximum explosion-proof pressure. However, this embodiment, through the eccentric arrangement of two arcs with different radii, allows the metal at the aluminum shell 20 port to undergo pre-extrusion by the large-radius arc and finishing by the small-radius arc during the sealing process. This optimizes the metal's plastic flow path, resulting in more thorough and uniform edge forming, thereby significantly improving the internal pressure strength of the capacitor after sealing. The small difference between the radius R0 of the first arc 211 and the radius R1 of the second arc 212 allows the metal at the port of the aluminum shell 20 to flow smoothly and continuously when transitioning from the second arc 212 to the first arc 211, avoiding stress concentration or local wrinkles caused by abrupt changes in the surface.

[0043] The axial distance H between the first circular platform 100 and the second circular platform 300 is equal to the sum of R0 and R1. This design ensures that the first arc 211 and the second arc 212 can be tangentially connected to the first circular platform 100 and the second circular platform 300, respectively, allowing the metal at the port of the aluminum shell 20 to move more smoothly in and out of the annular groove. The above-mentioned configuration enables the sealing pin structure of this embodiment to cover the sealing process of aluminum electrolytic capacitors with diameters ranging from φ22 to φ42 without changing the sealing pin structure, greatly improving the versatility of the sealing pin structure and the flexibility of the production line.

[0044] To verify the technical effectiveness of the sealing pin structure of the present disclosure embodiments, the applicant conducted numerous experimental tests. After sealing aluminum electrolytic capacitors of different diameters using the sealing pin structure of the present disclosure embodiments, their internal pressure (i.e., the maximum pressure that the capacitor can withstand) was tested, and the test results are shown in Table 1.

[0045] Table 1. Test data of sealed internal pressure of capacitors of different specifications As can be seen from the test data in Table 1, after sealing with the sealing pin structure of this embodiment, the internal pressure of capacitors of all diameters is significantly higher than the general industry standard (13KG to 15KG). Furthermore, the aforementioned internal pressure values ​​are also greater than the nominal internal pressure rating of aluminum-cased capacitors currently manufactured (11KG to 15KG). This indicates that the sealing pin structure of this embodiment can effectively improve the sealing strength and airtightness of the capacitors, providing a strong guarantee for the long-term reliable operation of capacitors under harsh conditions such as high temperature and high pressure.

[0046] Figure 6 This is a flowchart of a method for manufacturing a sealing pin structure according to an embodiment of this disclosure.

[0047] like Figure 6 As shown in the embodiments of this disclosure, a method for manufacturing a sealing pin structure is also provided, including the following steps: S100, Prepare the sealing needle substrate.

[0048] In some embodiments, the sealing pin substrate is made of SKT11 carbon steel. SKT11 carbon steel has the characteristics of high hardness and high wear resistance, and is suitable for manufacturing molds and tools that are subjected to high contact stress.

[0049] The sealing pin substrate can be prepared by machining methods such as turning, milling, and grinding, processing SKT11 carbon steel bars into the geometric shape of the sealing pin structure described in any of the aforementioned embodiments. During processing, strict control of each key dimensional parameter is necessary to ensure the forming accuracy of the sealing pin structure.

[0050] S200. A hard ceramic layer is formed on the outside of the sealing needle substrate to obtain the sealing needle structure.

[0051] In some embodiments, the hard ceramic layer is made of titanium nitride (TiN) coating. The main phase of the titanium nitride coating is titanium nitride, with a titanium-to-nitrogen atom ratio close to 1:1, and a NaCl-type face-centered cubic crystal structure. Trace impurities that may be present during the preparation process include: small amounts of residual metallic titanium (Ti) and titanium dioxide (TiO2), as well as trace amounts of argon (Ar), carbon (C), and alloying elements such as Fe, Cr, and V diffused from the sealing needle substrate. The titanium nitride coating has a typical golden-yellow appearance, and the color can be finely adjusted by changing the nitrogen content.

[0052] In some embodiments, the hard ceramic layer is prepared using a physical vapor deposition (PVD) process. Specifically, the processed sealing pin substrate is placed in a PVD coating apparatus, using high-purity titanium (Ti) as the target material and nitrogen (N2) as the reactant gas. Under vacuum conditions, titanium atoms react with nitrogen ions through methods such as arc evaporation or magnetron sputtering to deposit a titanium nitride coating on the surface of the sealing pin substrate. The temperature of the PVD process is typically controlled between 400°C and 500°C, a temperature range that does not adversely affect the internal structure and mechanical properties of the sealing pin substrate.

[0053] In some embodiments, the hard ceramic layer is deposited in two stages to form a double-layer sealing pin structure. Both layers are titanium nitride (TiN) coatings, but the deposition processes and film structures differ. The total coating thickness of the hard ceramic layer is controlled between 2.0 μm and 3.5 μm, and the thicknesses of the two coatings are as follows: The first layer (bottom titanium nitride layer): with a thickness of 0.8μm to 1.2μm. This bottom titanium nitride layer is mainly used to reduce internal stress, improve the adhesion between the hard ceramic layer and the sealing pin substrate, fill the micro-defects in the sealing pin substrate, and prevent the second layer (top titanium nitride layer) from cracking and falling off; the bottom titanium nitride layer has relatively coarse grains and better toughness.

[0054] The second layer (surface titanium nitride layer): with a thickness of 1.2μm to 2.0μm. This surface titanium nitride layer has high density, high hardness (2200HV to 2500HV), and low coefficient of friction. It can prevent aluminum material from sticking and is wear-resistant, ensuring that the sealing pin structure can withstand long-term rolling of the aluminum shell without wear or scratches, and ensuring that the rolled edge is smooth and without flat shoulders.

[0055] In a specific dual-layer physical vapor deposition (PVD) process, the process parameters for the first deposition of the underlying titanium nitride layer are as follows: substrate temperature 280℃ to 350℃, negative bias voltage 150V to 200V, nitrogen partial pressure 0.3Pa to 0.5Pa, titanium target arc current 60A to 70A; deposition time 40min to 60min, slow deposition to form a transition layer with low internal stress, density and good toughness, focusing on adhesion; after deposition, the process is stopped and allowed to cool down to stabilize the film stress.

[0056] During the second deposition of the titanium nitride surface layer, the process parameters were increased: the negative bias voltage was increased to 200V to 250V, the nitrogen partial pressure was finely adjusted to 0.4Pa to 0.6Pa, and the titanium target arc current was increased to 70A to 80A to enhance the ion bombardment energy; the deposition time was increased to 60min to 90min to achieve rapid and dense deposition, resulting in fine and uniform grains and a surface roughness Ra≤0.2μm.

[0057] Titanium nitride coating has the following advantages: 1. Ultra-high surface hardness, with a microhardness reaching 1800HV to 2400HV. The surface titanium nitride layer of the double-coated layer can reach 2200HV to 2500HV, far exceeding the hardness of SKT11 carbon steel (approximately 800HV). This significantly improves the wear resistance and scratch resistance of the sealing pin structure, significantly reducing wear under high-speed rolling extrusion conditions. 2. Low coefficient of friction, with a dry friction coefficient of 0.3 to 0.5, which improves the surface smoothness of the aluminum shell 20 during the sealing process and reduces wear. 3. Excellent chemical inertness, resistant to acids and alkalis at room temperature, and does not adhere to materials such as aluminum, copper, and plastics, making it particularly suitable for aluminum parts processing; 4. Moderate high-temperature resistance, stable and non-oxidizing in air below 500℃, and can be used at 600℃ for short periods, while ordinary carbon steel without coating is prone to tempering and softening at 300℃; 5. Thin and dense coating, the thickness of PVD titanium nitride coating is usually only 2.0μm to 3.5μm, the coating is uniform, and the mating dimensions of the sealing pin structure are hardly changed after processing, requiring no subsequent grinding.

[0058] It is understood that in other embodiments, the hard ceramic layer may also use other types of coating materials, such as titanium carbonitride (TiCN), chromium nitride (CrN), or diamond-like carbon (DLC), which can be selected according to specific working conditions and cost considerations.

[0059] In some embodiments, after forming the hard ceramic layer, a post-processing step may be included, such as polishing the surface of the hard ceramic layer to further reduce surface roughness and reduce frictional resistance during the sealing process.

[0060] In the description of this disclosure, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" 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 this disclosure and 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 this disclosure.

[0061] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include at least one of those features.

[0062] In the description of this disclosure, "multiple" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

[0063] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0064] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0065] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0066] Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A sealing needle structure, characterized in that, include: First circular platform; as well as A second circular platform is connected to the first circular platform via a connecting segment; The connecting segment has a concave surface on its outer circumferential side. The concave surface connects the first circular platform and the second circular platform and forms an annular groove between the first circular platform and the second circular platform. The first circular platform, the second circular platform and the concave surface are coaxially arranged. The contour line of the concave surface on the cross section passing through the axis of the first circular platform includes a first arc and a second arc connected in sequence. The first arc is set close to the first circular platform, and the second arc is set close to the second circular platform. The center of the first arc and the center of the second arc are eccentrically set in a direction perpendicular to the axis of the first circular platform. The radius of the first arc is smaller than the radius of the second arc.

2. The sealing needle structure according to claim 1, characterized in that, The distance between the first circular platform and the second circular platform along the axial direction of the first circular platform is equal to the sum of the radius of the first circular arc and the radius of the second circular arc.

3. The sealing needle structure according to claim 2, characterized in that, The radius of the first arc is between 0.90 mm and 1.05 mm; The radius of the second arc is 0.95 mm to 1.15 mm.

4. The sealing pin structure according to any one of claims 1 to 3, characterized in that, The vertical distance between the maximum radial dimension of the first circular platform and the minimum radial dimension of the connecting segment along the direction perpendicular to the axial direction of the first circular platform is greater than the radius of the first arc and less than the radius of the second arc.

5. The sealing needle structure according to claim 4, characterized in that, The first circular platform includes a circumferential surface and a first plane and a second plane disposed opposite to each other along the axial direction of the first circular platform. The circumferential surface is a cylindrical surface. The first plane is positioned away from the connecting segment, and an arc transition is formed between the first plane and the circumferential surface; The second plane is connected to the connecting segment, and there is an arc transition between the second plane and the circumferential surface.

6. The sealing needle structure according to claim 5, characterized in that, The axial dimension of the first circular platform is 0.6 mm to 0.9 mm; The maximum diameter of the first circular platform is 8 mm.

7. The sealing needle structure according to claim 4, characterized in that, The second circular platform has a conical surface on its outer circumferential side. The conical surface is coaxially arranged with the concave surface, and the conical surface can form a small end face on the side of the second circular platform that connects to the connecting segment.

8. The sealing needle structure according to claim 7, characterized in that, The small end face is a plane perpendicular to the axis of the first circular platform; The intersection of the second arc and the second circular platform is located on the small end face, and the intersection of the second arc and the second circular platform is spaced apart from the intersection of the small end face and the conical surface.

9. The sealing needle structure according to claim 7, characterized in that, The second circular platform is also connected to the connecting part via the third circular platform; The third circular platform and the connecting portion are coaxially arranged with the concave surface; The radial dimension of the third circular platform is the same as the radial dimension of the small end face.

10. A method for manufacturing a sealing pin structure, characterized in that, include: Preparation of sealing needle matrix; A hard ceramic layer is formed on the outer side of the sealing needle substrate to obtain the sealing needle structure as described in any one of claims 1 to 9.

Images