A sealing tool for the ceramic coating of the surface of a metal liner

Abstract

The utility model discloses a kind of sealing tool for ceramic processing of metal inner container surface, including insulating shell, metal inner container, compression ring, second sealing insulating layer, fastening assembly and conductive grounding assembly.Metal inner container is coaxially arranged in the cavity of shell, and its non-processing area covers first sealing insulating layer.Compression ring and sealing layer jointly realize sealing positioning, fastening assembly forms axial compression force, and conductive assembly guarantees cathode grounding.Each connecting cable one end connects metal inner container inner wall, and the other end connects the metal outer wall of sealed container, and the metal outer wall of sealed container is connected to ground potential;Among them, the preset outer surface area of metal inner container is exposed to electrolyte to constitute anode working surface.The sealing tool effectively limits processing area, improves the stability and safety of micro-arc oxidation process, and has good sealing, repeatability and operation convenience.

Description

Technical Field

[0001] This utility model relates to the field of micro-arc oxidation technology, and in particular to a sealing tool for ceramic treatment of the surface of a metal liner. Background Technology

[0002] Metal liners are widely used in aerospace, chemical, medical, and food processing industries. Especially in complex environments involving high temperatures, high pressures, and highly corrosive media, optimizing their surface properties has become a research hotspot. Traditional surface treatment methods such as spraying, electroplating, and thermal spraying, while improving the corrosion resistance and mechanical properties of metal liners to some extent, still suffer from drawbacks such as weak adhesion, poor coating uniformity, and complex processes. Furthermore, these methods cause significant environmental pollution during processing.

[0003] Micro-arc oxidation (MAO) technology, as a highly efficient and environmentally friendly metal surface ceramicization treatment technology that has emerged in recent years, can generate a dense, hard ceramic coating that is metallurgically bonded to the substrate on the surface of metal substrates such as aluminum, titanium, and magnesium, exhibiting excellent corrosion resistance, wear resistance, and insulation properties. However, when performing MAO treatment on localized areas of metal liners, the liner structure is usually closed or semi-closed, making it difficult to effectively control the treatment area in a liquid electrolysis environment. This can easily lead to problems such as oxidation of non-target areas or poor electrode contact, severely affecting the treatment effect and product consistency.

[0004] Existing micro-arc oxidation electrolysis devices generally lack dedicated sealing and fixing fixtures, making it impossible to effectively define and protect the treatment area of ​​the metal liner. This is especially true when dealing with small, complex, or high-precision metal liners, where existing technologies are clearly insufficient. Therefore, there is an urgent need for a sealing fixture for the ceramicization treatment of metal liners that is structurally sound, has superior sealing performance, reliable positioning, and is suitable for the micro-arc oxidation environment. This fixture would address the technical bottlenecks in controlling the treatment area, improving treatment quality, and enhancing operational safety in existing processes. Utility Model Content

[0005] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a sealing tool for ceramic treatment of the surface of metal liner, so as to improve the stability and safety of the micro-arc oxidation process of metal liner.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a sealing fixture for ceramic treatment of the surface of a metal liner, comprising:

[0007] An insulating shell is fixedly installed inside a sealed container for containing electrolyte. The outer wall of the sealed container is metal and the inner wall is insulated. The insulating shell has a through-hole inner liner cavity in the middle.

[0008] A metal inner liner is coaxially assembled within the inner liner accommodating cavity. The untreated area of ​​the inner wall of the metal inner liner is covered with a first sealing and insulating layer, which tightly fills the pore structure of the inner wall of the metal inner liner.

[0009] A clamping ring is symmetrically arranged at both ends of the inner liner cavity, and the inner ring surface of the clamping ring is pressed against the axial end of the outer wall of the metal inner liner.

[0010] The second sealing and insulating layer covers the outer ring surface and end face of the compression ring and forms a sealed contact with the end face of the insulating shell;

[0011] Fastening components, including:

[0012] Multiple threaded holes are arranged in a ring on the end face of the insulating housing;

[0013] The second insulating hole penetrates the clamping ring;

[0014] A first insulating hole penetrating the second sealing insulating layer;

[0015] A fastening bolt, which passes through the first insulating hole and the second insulating hole in sequence and is screwed into the threaded hole to form an axial clamping force;

[0016] Conductive grounding components include:

[0017] Multiple connecting cables, one end of each connecting cable is connected to the inner wall of the metal liner, and the other end is connected to the outer metal wall of the sealed container, wherein the outer metal wall of the sealed container is connected to the earth potential;

[0018] The predetermined outer surface area of ​​the metal liner is exposed in the electrolyte to form the anode working surface.

[0019] Furthermore, the insulating housing includes an upper shell and a lower shell that are spliced ​​together, and the upper shell and the lower shell are detachably connected.

[0020] Furthermore, the mating surfaces of the upper shell and the lower shell are provided with staggered positioning bosses and positioning grooves. The positioning bosses have a trapezoidal cross-section, and the inclined surfaces of the positioning bosses are interference-fitted with the inner walls of the positioning grooves.

[0021] Furthermore, the first sealing insulation layer is a double-layer sleeve structure, comprising:

[0022] The inner silicone rubber sealing sleeve tightly covers the inner wall of the metal liner;

[0023] The outer rigid insulating sleeve has raised ribs on its outer surface;

[0024] The raised rib is interference-fitted with the groove on the inner wall of the metal liner.

[0025] Furthermore, the clamping ring is embedded with a wave-shaped spring plate, the spring plate having a peak spacing of 10-15mm and a peak height of 1.5-2mm, and both ends of the spring plate being fixed in a pre-drilled limiting groove in the clamping ring.

[0026] Furthermore, the insulating housing sidewall is provided with heat dissipation fins, the fin thickness is 2mm, and the fin height is 8-12mm.

[0027] Furthermore, multiple through holes are formed on the surface of the heat dissipation fins, and the diameter of each through hole is 3mm.

[0028] Furthermore, the head of the fastening bolt is provided with a mechanical pressure indicator ring, the mechanical pressure indicator ring comprising:

[0029] A color-coded ring that rotates coaxially with the fastening bolt;

[0030] A transparent observation window fixed to the head of the fastening bolt;

[0031] When the axial clamping force is sufficient, the green area of ​​the color mark ring aligns with the transparent observation window.

[0032] The beneficial effects of this utility model are:

[0033] (1) High-efficiency sealing performance: By setting a first sealing insulation layer and a second sealing insulation layer, combined with a pressure ring and a multi-point bolt fastening structure, a double seal is achieved on the metal inner liner, which can effectively prevent electrolyte leakage and ensure that non-target areas are protected from electrolytic corrosion during the treatment process.

[0034] (2) Precise and controllable treatment area: The non-treatment area of ​​the metal inner liner is covered by the first sealing insulation layer. Combined with the precise limitation of the shell structure, it ensures that only the preset outer surface is exposed to the electrolyte, forming a stable anode working surface, thereby improving the consistency and precision of the ceramicization treatment.

[0035] (3) The structure is easy to assemble and highly reusable: The modular design of each component of this utility model makes it easy to disassemble and assemble, maintain and replace, and is suitable for the rapid replacement and repeated processing of metal liners of various specifications, which significantly improves processing efficiency.

[0036] (4) Improved electrical safety and reliability: The conductive grounding component ensures that a stable grounding circuit is formed between the metal inner liner and the sealed container shell, reducing the risk of abnormal discharge or workpiece damage caused by unstable potential, and enhancing the electrical safety of the processing.

[0037] (5) Excellent corrosion resistance and insulation: The insulating shell and insulating layer materials in this utility model are selected from materials with excellent corrosion resistance and insulation performance, which can work stably for a long time in the environment of strong corrosion of electrolyte and high voltage, thereby improving the life and reliability of the whole machine.

[0038] In summary, the tooling structure of this utility model is reasonably designed and has a high degree of functional integration. It can provide precise, safe and repeatable operating conditions in the micro-arc oxidation process, significantly improve the technical problems existing in traditional processes such as leakage, oxidation of non-target areas and poor electrical contact, and has broad application prospects. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the sealing fixture used for ceramic treatment of the surface of a metal inner liner in this utility model;

[0040] Figure 2 This is a side sectional view of the insulating shell in this utility model;

[0041] Figure 3 This is a side sectional view of the first sealing and insulating layer in this utility model.

[0042] Reference numerals: 1. Insulating shell; 11. Upper shell; 12. Lower shell; 13. Positioning boss; 14. Positioning groove; 2. Metal inner liner; 3. Compression ring; 4. First sealing insulation layer; 41. Inner silicone rubber sealing sleeve; 42. Outer hard insulating sleeve; 43. Rib; 5. Second sealing insulation layer; 6. Fastening bolt; 7. Connecting cable; 8. Heat dissipation fins; 9. Through hole. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Identical components are indicated by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, and the terms "bottom surface," "top surface," "inner," and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0044] Example 1, referring to Figure 1 This embodiment provides a sealing fixture for ceramic treatment of the surface of a metal liner. Its core is to improve the stability and safety of the micro-arc oxidation process of the metal liner 2 through multi-layer sealing and reliable grounding.

[0045] The sealing fixture includes:

[0046] An insulating housing 1 is fixedly disposed inside the electrolytic cell (i.e., the "sealed container" in the claims) of the micro-arc oxidation equipment. The electrolytic cell is used to contain the electrolyte, and its outer wall is metal with an insulating lining (or the inner wall is made of insulating material directly). The insulating housing 1 is made of engineering plastics (such as PTFE, PPO) or ceramic materials that are resistant to electrolytic corrosion and have high insulation properties. A through-hole inner liner accommodating cavity is provided in the middle of the insulating housing 1 for installing a metal inner liner 2.

[0047] A metal inner liner 2, coaxially assembled within the inner liner cavity, serves as the workpiece to be processed. The non-processed areas of the inner wall of the metal inner liner 2 are covered with a first sealing and insulating layer 4. This first sealing and insulating layer 4 tightly fills the pores and gaps in the inner wall of the metal inner liner 2. It can be made of a coating material resistant to electrolyte corrosion and possessing excellent flexibility (such as silicone rubber coating or epoxy resin), or a prefabricated sealing sleeve, the purpose of which is to prevent electrolyte from penetrating into the interior of the inner liner.

[0048] The clamping ring 3 is symmetrically positioned at both ends of the inner liner cavity. The inner ring surface of the clamping ring 3 is pressed against the axial end of the outer wall of the metal inner liner 2, forming preliminary mechanical positioning and axial sealing.

[0049] The second sealing insulation layer 5 covers the outer ring surface and end face of the compression ring 3 and forms a sealed contact with the end face of the insulating housing 1, together forming a second barrier to prevent electrolyte leakage from the end.

[0050] Fastening components are used to provide a stable and reliable axial clamping force. They include:

[0051] Multiple threaded holes are arranged in a ring on the end face of the insulating housing 1;

[0052] The second insulating hole penetrates the clamping ring 3;

[0053] The first insulating hole penetrating the second sealing insulation layer 5;

[0054] The fastening bolt 6 passes through the first insulating hole and the second insulating hole in sequence and is screwed into the threaded hole. By tightening the bolt, the required axial clamping force is generated, which clamps the clamping ring 3, the second sealing insulating layer 5 and the insulating shell 1 into a whole.

[0055] A conductive grounding assembly is used to establish a safe and reliable electrolysis circuit. It includes:

[0056] Multiple connecting cables 7 are provided, with one end of each cable 7 connected (e.g., by welding or bolting) to the inner wall of the metal liner 2 (i.e., the anode area), and the other end connected to the outer metal wall of the electrolytic cell (i.e., the cathode grounding terminal). The outer metal wall of the electrolytic cell is reliably connected to the earth's potential.

[0057] Among them, the predetermined outer surface area of ​​the metal inner liner 2 (i.e. the area not covered by the insulating shell 1 and the clamping ring 3) is exposed to the electrolyte, forming the anode working surface for micro-arc oxidation reaction.

[0058] Working principle of Example 1:

[0059] In actual use, the untreated areas (inner wall and ends) of the metal inner liner 2 are first pre-covered or the first sealing insulation layer 4 is installed. Then, it is coaxially inserted into the inner liner receiving cavity of the insulating shell 1. Next, clamping rings 3 are installed at both ends of the insulating shell 1 to ensure good contact between the second sealing insulation layer 5 and the end face of the insulating shell 1. Finally, torque is applied and tightened by the fastening bolts 6 of the fastening assembly to form a stable structural connection and a double-layer seal at the ends.

[0060] When the micro-arc oxidation device is started, the electrolyte is injected into the electrolytic cell, and the liquid only contacts the preset area (anode working surface) on the outer wall of the metal inner tank 2 that is not covered by the insulating layer. This area is subjected to micro-arc discharge by an externally applied high-voltage pulse current, and a ceramic oxide layer is generated on its surface.

[0061] Meanwhile, the connecting cable 7 in the conductive grounding assembly connects the metal inner tank 2 (anode) to the metal outer shell of the electrolytic cell (cathode), forming a complete electrolytic circuit and ensuring stable current conduction. Throughout the process, because the tooling has a multi-layer sealing system consisting of a first sealing insulation layer 4, a clamping ring 3, and a second sealing insulation layer 5, the electrolyte will not leak into the inner tank or non-treated areas, thus ensuring the precision and uniformity of the oxidation area and effectively preventing secondary defects caused by liquid leakage or uneven electric field distribution.

[0062] Example 2, refer to Figure 2 Based on Example 1, this example optimizes the structure of the insulating shell 1, which facilitates quick disassembly and assembly when replacing metal inner liner 2 of different specifications or when maintaining the tooling, thereby improving the versatility and ease of operation of the equipment.

[0063] The insulating housing 1 includes an upper shell 11 and a lower shell 12 that are spliced ​​together. The upper shell 11 and the lower shell 12 are detachably connected by bolts or buckles.

[0064] Preferably, the mating surfaces of the upper shell 11 and the lower shell 12 are provided with staggered positioning bosses 13 and positioning grooves 14. The cross-section of the positioning bosses 13 is trapezoidal. This trapezoidal design allows the inclined surface of the positioning bosses 13 to form an interference fit with the inner wall of the positioning grooves 14, which not only provides a self-guiding effect during assembly and achieves preliminary mechanical positioning, but also generates a radial component force under the action of fastening components, forming a self-locking effect, significantly enhancing the stability and sealing of the upper and lower shells after connection, and preventing shell displacement caused by vibration during the micro-arc oxidation process.

[0065] Working principle of Example 2:

[0066] During operation, the lower shell 12 is first placed in the electrolytic cell, then the metal inner liner 2 with its inner wall already sealed is placed into the cavity of the lower shell 12, and then the upper shell 11 is axially connected to the lower shell 12. The initial positioning is completed by the self-guiding action of the positioning boss 13 and the positioning groove 14. Then, the clamping rings 3 at both ends and the second sealing insulation layer 5 are installed, and the fastening bolts 6 are tightened to complete the assembly and fastening of the entire tooling.

[0067] This detachable, modular design has the following advantages:

[0068] Easy to disassemble and assemble: The shell can be quickly opened to replace the inner liner, adapting to the processing needs of multiple batches and models of workpieces.

[0069] High repeatability and positioning accuracy: The fit between the trapezoidal boss and the groove ensures precise alignment in every assembly, guaranteeing the consistency of the electrolytic treatment area.

[0070] Stable and reliable structure: The self-locking effect generated by the interference fit allows it to maintain stable engagement even under high-voltage electrolysis environment, effectively preventing loosening and leakage.

[0071] Example 3, based on Example 1 or 2, further optimizes the first sealing insulation layer 4, the compression ring 3, the insulating shell 1 and the fastening bolt 6.

[0072] As a preferred embodiment of the first sealing insulation layer 4, refer to Figure 3 The first sealing and insulating layer 4 has a double-layer sleeve structure to enhance the sealing reliability, insulation protection effect, and structural support of the inner wall of the metal liner 2. It includes:

[0073] The inner silicone rubber sealing sleeve 41 is made of silicone rubber material with high elasticity, high temperature resistance and electrolyte corrosion resistance. Its function is to tightly cover the inner wall of the metal inner liner 2 and use its softness to fill the micro-uneven areas to achieve a primary seal.

[0074] The outer rigid insulating sleeve 42 is made of an insulating material with high dielectric strength and mechanical strength (such as high-strength epoxy glass fiber or polyimide). Its outer surface is provided with annular ribs 43.

[0075] The raised rib 43 forms an interference fit with the pre-machined annular groove on the inner wall of the metal inner liner 2. This structure generates radial clamping force after assembly, which not only firmly locks the double-layer sealing sleeve onto the metal inner liner 2, preventing it from shifting or falling off during processing, but also further enhances the sealing effect.

[0076] As a preferred embodiment of the clamping ring 3, the clamping ring 3 has a corrugated (or wavy) spring sheet (not shown) embedded in it to provide a continuous elastic compensation force to cope with the decrease in preload caused by thermal expansion and contraction or vibration, thereby enhancing the reliability of the seal and the anti-loosening performance.

[0077] The spring sheet is made of stainless steel with excellent elasticity. Its crest spacing is designed to be 10-15mm, and the wave height is designed to be 1.5-2mm. This parameter range has been optimized to provide sufficient elastic deformation while maintaining stable mechanical properties.

[0078] The two ends of the spring sheet are fixed in the pre-opened limiting grooves of the clamping ring 3 to ensure that it will not move in the ring direction.

[0079] As a preferred embodiment of the insulating housing 1, refer to Figure 2 The side wall of the insulating housing 1 is provided with heat dissipation fins 8, which are intended to improve the heat dissipation efficiency of the tooling during operation, reduce the system heat load, and ensure the thermal stability of the micro-arc discharge process and the long-term performance of the insulating material.

[0080] The heat dissipation fins 8 and the insulating shell 1 can be integrally molded or bonded together with high-strength thermally conductive adhesive to ensure a good heat conduction path.

[0081] The fin thickness is preferably 2mm to balance structural strength and thermal conductivity.

[0082] The fin height is preferably 8-12mm to provide a sufficiently large heat dissipation surface area.

[0083] Preferably, multiple through holes 9 are formed on the surface of the heat dissipation fins 8. The diameter of each through hole 9 is 3 mm. These through holes 9 can form additional airflow channels between the fins, significantly enhancing the efficiency of air convection heat dissipation and preventing local overheating. At the same time, the 3 mm hole diameter can achieve a good balance between enhancing heat dissipation and maintaining the structural strength of the fins.

[0084] As a preferred embodiment of the fastening bolt 6, the head of the fastening bolt 6 is provided with a mechanical pressure indicator ring, which is used to intuitively indicate whether the tightening force of the bolt has reached the preset standard value, realize the quantitative control of the assembly process, ensure consistent clamping force, and avoid sealing failure or damage to parts due to overtightness or looseness.

[0085] Mechanical pressure indicator rings include:

[0086] A color mark ring that rotates coaxially with the screw of fastening bolt 6 (linkage can be achieved through internal threads or a slot structure). The ring surface has three color zones: red zone (insufficient clamping force), yellow zone (critical clamping force), and green zone (clamping force meets the standard).

[0087] A transparent viewing window, made of high-strength transparent polycarbonate material, is fixedly mounted on the housing of the head of the fastening bolt 6, for observing the color of the color mark ring below it.

[0088] Working principle of Example 3:

[0089] During the tightening of bolt 6, the bolt's thread rotates forward, generating axial clamping force. Simultaneously, the color-coded ring, linked to the thread, also rotates. This indicator mechanism is pre-calibrated so that when the axial clamping force reaches a preset standard value, the green area on the color-coded ring rotates precisely to align with the transparent observation window, allowing the operator to visually assess the situation. If a red or yellow area is observed, tightening must continue or over-tightening should be checked. This design enables intuitive and rapid inspection of assembly quality.

[0090] The above are merely preferred embodiments of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are within its protection scope. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within its protection scope.

Claims

1. A sealing fixture for ceramic treatment of the surface of a metal liner, applied in a micro-arc oxidation electrolysis device, characterized in that, include: An insulating shell (1) is fixedly installed inside a sealed container. The sealed container is used to contain electrolyte. The outer wall of the sealed container is metal and the inner wall is insulated. The insulating shell (1) has a through-hole inner liner cavity in the middle. A metal inner liner (2) is coaxially assembled in the inner liner cavity. The non-treated area of ​​the inner wall of the metal inner liner (2) is covered with a first sealing and insulating layer (4). The first sealing and insulating layer (4) tightly fills the pore structure of the inner wall of the metal inner liner (2). A clamping ring (3) is symmetrically arranged at both ends of the inner liner cavity, and the inner ring surface of the clamping ring (3) is pressed against the axial end of the outer wall of the metal inner liner (2). The second sealing insulation layer (5) covers the outer ring surface and end face of the compression ring (3) and forms a sealed contact with the end face of the insulating shell (1); Fastening components, including: A ring array of multiple threaded holes on the end face of the insulating housing (1); The second insulating hole penetrates the clamping ring (3); A first insulating hole penetrating the second sealing insulating layer (5); Fastening bolt (6), the fastening bolt (6) passes through the first insulating hole and the second insulating hole in sequence and is screwed into the threaded hole to form an axial clamping force; Conductive grounding components include: Multiple connecting cables (7), one end of each connecting cable (7) is connected to the inner wall of the metal inner liner (2), and the other end is connected to the outer metal wall of the sealed container. The outer metal wall of the sealed container is connected to the ground potential. The outer surface area of ​​the metal liner (2) is exposed to the electrolyte to form the anode working surface.

2. The sealing fixture for ceramic treatment of metal inner liner surface according to claim 1, characterized in that: The insulating housing (1) includes an upper shell (11) and a lower shell (12) that are spliced ​​together, and the upper shell (11) and the lower shell (12) are detachably connected.

3. The sealing fixture for ceramic treatment of metal liner surfaces according to claim 2, characterized in that: The mating surfaces of the upper shell (11) and the lower shell (12) are provided with staggered positioning bosses (13) and positioning grooves (14). The positioning bosses (13) have a trapezoidal cross section, and the inclined surface of the positioning bosses (13) is interference-fitted with the inner wall of the positioning grooves (14).

4. The sealing fixture for ceramic treatment of metal inner liner surface according to claim 1, characterized in that: The first sealing insulation layer (4) is a double-layer sleeve structure, including: The inner silicone rubber sealing sleeve (41) tightly covers the inner wall of the metal inner liner (2); The outer rigid insulating sleeve (42) has raised ribs (43) on its outer surface; The rib (43) is interference-fitted with the groove on the inner wall of the metal liner (2).

5. The sealing fixture for ceramic treatment of metal liner surfaces according to claim 1, characterized in that: The clamping ring (3) is embedded with a wave-shaped spring plate. The spring plate has a peak spacing of 10-15mm and a peak height of 1.5-2mm. Both ends of the spring plate are fixed in the limiting grooves pre-opened in the clamping ring (3).

6. The sealing fixture for ceramic treatment of metal liner surfaces according to claim 1, characterized in that: The insulating shell (1) has heat dissipation fins (8) on its side wall. The fins are 2 mm thick and 8-12 mm high.

7. The sealing fixture for ceramic treatment of metal liner surfaces according to claim 6, characterized in that: The heat dissipation fins (8) have multiple through holes (9) on their surface, and the diameter of each through hole (9) is 3 mm.

8. The sealing fixture for ceramic treatment of metal inner liner surface according to claim 1, characterized in that: The head of the fastening bolt (6) is provided with a mechanical pressure indicator ring, the mechanical pressure indicator ring comprising: A color mark ring that rotates coaxially with the fastening bolt (6); A transparent observation window fixed to the head of the fastening bolt (6); When the axial clamping force is sufficient, the green area of ​​the color mark ring aligns with the transparent observation window.

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