A grinding tool and method for a rear dynamic ring seal face

Abstract

The application belongs to the field of aero-engine manufacturing, and discloses a kind of rear dynamic ring sealing surface grinding tool and method, including the tool body designed as disc structure, first positioning groove is opened in end face to gap fit rear dynamic ring outer edge, center concave groove gap fit contains rear dynamic ring center convex part, annular boss structure is formed between the two, multiple second positioning grooves are provided on boss in circumferential direction, and are matched with rear dynamic ring convex rib one by one Clamping, ensure that rear dynamic ring cavity bottom surface is closely attached to tool end face after assembly. Through the synergistic effect of multiple positioning grooves, the displacement and vibration of the rear dynamic ring during the grinding process can be accurately constrained, the relative sliding between the tool and the part is reduced, and excessive wear caused by the difference in material hardness of the general platform is avoided. Using this tool can significantly reduce tool wear, ensure that the flatness and roughness of the sealing surface meet the standards, improve the processing qualification rate and quality stability, reduce the need for rework, and overall improve the grinding efficiency and reliability.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine manufacturing, specifically to the field of machining technology, and particularly relates to a grinding fixture and method for the rear dynamic ring sealing surface. Background Technology

[0002] In the field of aero-engine manufacturing, the rear dynamic ring, as a key component of the turbine section, has a significant impact on the overall engine performance due to its sealing surface performance. This sealing surface must not only prevent gas leakage to improve thermal and propulsive efficiency, but also maintain stable airflow to ensure uniform stress on the turbine blades, thereby enhancing engine stability and reliability. For a specific model of rear dynamic ring, its sealing surface is significantly larger than that of conventional products, with a maximum outer diameter of φ116mm and an effective sealing surface range of 84mm. It must also meet high precision requirements of 0.003mm flatness and Ra0.05μm roughness. This part is manufactured using 38CrMoAlA high-grade nitrided steel. After nitriding treatment, the sealing surface achieves a hardness of HRC≥58, while the remaining surfaces are protected by chemical oxidation treatment. Furthermore, the sealing surface must be ground to ensure... The thickness dimension is mm.

[0003] There are obvious drawbacks to using a general-purpose grinding platform for machining: First, due to the high surface hardness of the parts, grinding large sealing surfaces can easily cause wear on the platform, making it difficult to guarantee flatness. In addition, the platform needs to be frequently dressed and lapped, requiring extremely high dressing precision, which makes machining difficult. Second, due to the difference in materials and hardness between the parts and the platform, the platform is prone to wear and gaps, and residual grinding paste can easily scratch the sealing surface, making it difficult to meet the surface roughness requirements. Third, the machining pass rate is only 40%, with a high rework rate and poor quality stability.

[0004] This shows that the grinding process of the large sealing surface of the rear dynamic ring has problems such as difficulty in ensuring accuracy, unstable quality, and low efficiency. Summary of the Invention

[0005] This invention provides a grinding fixture and method for the rear dynamic ring sealing surface. By using this fixture and method, the problems of difficulty in ensuring accuracy, unstable quality and low efficiency in the grinding of the large sealing surface of the rear dynamic ring can be effectively solved.

[0006] To achieve the above objectives, the present invention employs the following technical content: A grinding fixture for a rear dynamic ring sealing surface includes: a fixture body; The tooling body is arranged in a disc-shaped structure, and a circular first positioning groove is opened on the end face. The outer edge of the rear moving ring is in clearance fit with the first positioning groove, and the outer edge of the rear moving ring can be inserted into the first positioning groove. A concave groove is provided at the center of the end face of the tooling body, and the central convex structure of the rear moving ring is in clearance fit with the concave groove, so that the central convex structure of the rear moving ring can be embedded in the concave groove. A ring-shaped boss structure is formed between the first positioning groove and the concave groove. Multiple second positioning grooves are provided on the boss structure along the circumferential direction. The number of second positioning grooves matches the number of boss ribs of the rear moving ring. Each boss rib can be inserted into the corresponding second positioning groove. After the rear moving ring is assembled with the grinding fixture, the bottom surface of the cavity of the rear moving ring fits tightly with the end face of the grinding fixture.

[0007] Furthermore, the end face of the first positioning groove and the tooling body, the first positioning groove and the boss structure, and the two sides of the second positioning groove all adopt rounded transitions.

[0008] Furthermore, the angle of the arc transition is R0.5~R1; where R is the radius of the arc; R0.5~R1 indicates that the radius of the arc is between 0.5 units and 1 unit.

[0009] Furthermore, the tooling body is made of polytetrafluoroethylene.

[0010] 5. A grinding fixture for a rear dynamic ring sealing surface according to claim 4, characterized in that, further, the fixture body is made of SFB-2 polytetrafluoroethylene.

[0011] A grinding method for a rear dynamic ring sealing surface, based on the aforementioned grinding fixture for a rear dynamic ring sealing surface, includes: A grinding technique combining figure-eight motion and 180° rotation is used to grind the rear moving ring sealing surface on a cast iron platform to remove the chemical oxide layer on the sealing surface; wherein, the grinding motion of the rear moving ring is driven by a grinding fixture on the rear moving ring sealing surface. A grinding technique combining figure-eight motion and 180° rotation is used to grind the sealing surface of the rear dynamic ring with the chemical oxide layer on a glass platform to obtain a pre-ground rear dynamic ring. Three pre-ground moving rings were randomly selected, and a sawtooth cyclic method was used to perform mutual grinding on the two pre-ground moving rings to obtain a finely ground moving ring; during the grinding process, any one of the moving rings was installed into a grinding fixture for the sealing surface of the moving ring.

[0012] Furthermore, after randomly selecting three pre-ground moving rings and using a sawtooth cyclic method to perform pairwise mutual grinding of the pre-ground moving rings, the process further includes: The sealing surface of the precision-ground rotating ring is polished on a felt wheel to obtain a well-ground rotating ring.

[0013] Furthermore, before grinding the rear moving ring sealing surface on the cast iron platform using the figure-eight motion combined with 180° rotation, the grinding method further includes: The rear dynamic ring is subjected to nitriding treatment; After polishing the sealing surface of the precision-ground rotating ring on a felt wheel, the process further includes: The ground rear rotating ring is then cleaned, inspected, and oil-sealed in sequence.

[0014] Furthermore, in the grinding method that combines figure-eight motion with 180° rotation, the rear dynamic ring sealing surface is ground on a cast iron platform using W7~W10 diamond grinding paste. The grinding technique, which combines figure-eight motion with 180° rotation, grinds the rear dynamic ring sealing surface of the chemical oxide layer on a glass platform using W7~W10 diamond grinding paste. The process involves randomly selecting three pre-ground moving rings and using a sawtooth cyclic method to perform pairwise mutual grinding on the pre-ground moving rings. W7~W10 diamond grinding paste is used to perform pairwise mutual grinding on the pre-ground moving rings.

[0015] Furthermore, the process of randomly selecting three pre-ground moving rings and using a sawtooth cyclic method to perform pairwise mutual grinding of the pre-ground moving rings includes: From all the pre-grinding moving rings, three were randomly selected and designated as No. 1, No. 2, and No. 3; the cyclic grinding process was divided into three steps: first step: Insert No. 2 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 1 against No. 2. Insert No. 1 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 1 against No. 3. Insert No. 3 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 2 with No. 3. Step Two: Insert No. 1 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 1 against No. 2. Insert No. 2 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 2 against No. 3. Insert No. 3 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 1 against No. 3. Step 3: Insert No. 2 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 2 against No. 3. Insert No. 3 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 1 against No. 3. Insert No. 1 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 1 against No. 2.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a grinding fixture for the sealing surface of a rear moving ring, comprising a fixture body designed as a disc, with a circular first positioning groove on the end face to clearance fit the outer edge of the rear moving ring, and a central concave groove to clearance fit the central protrusion of the rear moving ring, forming an annular boss structure. Multiple second positioning grooves are provided circumferentially along the upper edge of the boss, matching and securing with the boss ribs of the rear moving ring to ensure a tight fit between the bottom surface of the rear moving ring cavity and the end face of the fixture. Through the synergistic effect of the multi-level positioning grooves, the displacement and vibration of the rear moving ring during the grinding process can be precisely constrained, reducing relative sliding between the fixture and the part, thereby avoiding excessive wear caused by material hardness differences on a general-purpose platform. Simultaneously, the tight fit of the end faces forms a sealing interface, effectively preventing grinding paste from seeping into gaps. Using this fixture significantly reduces fixture wear, ensures that the flatness and roughness of the sealing surface meet standards, improves the processing qualification rate and quality stability, reduces rework requirements, and overall improves grinding efficiency and reliability.

[0017] Preferably, in this invention, the arc transition treatment significantly reduces stress concentration at the edge of the positioning groove, preventing microscopic impact damage caused by rigid contact during workpiece assembly. This design further protects the surface integrity of the workpiece, reduces accidental scratches caused by mechanical interference, and ensures uniform surface roughness during the grinding process.

[0018] Preferably, in this invention, limiting the range of the arc radius ensures a balance between the smoothness of the transition surface and the structural strength: too small a radius fails to effectively disperse stress, while too large a radius weakens positioning accuracy. This optimization allows the tooling to both buffer assembly impacts and maintain rigid support for the workpiece, enhancing the reliability of the grinding process.

[0019] Preferably, in this invention, the polytetrafluoroethylene (PTFE) material imparts self-lubricating properties and a low coefficient of friction to the tooling, significantly reducing the probability of wear between it and the workpiece. Its soft properties absorb vibration energy, preventing the hard platform from scratching the sealing surface, while also reducing the tooling's own wear and extending its service life.

[0020] Preferably, in this invention, SFB-2 type polytetrafluoroethylene is selected to further enhance wear resistance and dimensional stability. This material maintains deformation resistance under high-pressure grinding conditions, ensuring long-term accuracy of the positioning structure and avoiding batch quality fluctuations caused by tooling deformation.

[0021] This invention also provides a grinding method for the rear dynamic ring sealing surface. Based on the aforementioned grinding fixture for the rear dynamic ring sealing surface, this method first uses a cast iron platform combined with a special fixture to drive the rear dynamic ring to perform an "8-shaped motion + 180° rotation" to remove the oxide layer. Then, the dynamic grinding method is repeated on a glass platform to achieve preliminary fine grinding. Finally, three initially ground workpieces are randomly selected and subjected to pairwise fine grinding using a sawtooth cyclic method. The staged grinding strategy fully utilizes the cutting force of the cast iron platform and the flatness of the glass platform, and the dynamic composite motion eliminates unidirectional textures. The special fixture ensures accurate workpiece positioning and force transmission stability throughout the process, avoiding surface scratches caused by vibration. In the final grinding stage, the self-matching material similarity between workpieces is utilized to achieve microscopic correction of the sealing surface under controlled conditions. The dynamic grinding method of this method uniformizes the force distribution and avoids local deviations. The automatic compensation of system errors during the grinding process ultimately achieves simultaneous improvement in the flatness and roughness of the sealing surface, significantly enhancing the processing qualification rate and quality stability, and greatly reducing the rework rate.

[0022] Preferably, in this invention, the felt wheel polishing process effectively removes the microscopic peaks and valleys remaining after fine grinding, and further reduces the surface roughness value through flexible contact. This process overcomes the limitations of mechanical grinding, enabling the sealing surface to achieve a mirror finish and meeting the sealing requirements under high operating conditions.

[0023] Preferably, in this invention, nitriding pretreatment enhances the hardness of the substrate, providing a uniform material base for subsequent grinding; the final cleaning-inspection-oil closed-loop process ensures the rust prevention preservation and quality traceability of the finished product, forming a full-chain quality control.

[0024] Preferably, in this invention, diamond polishing paste with the same grit size range is used throughout the process to maintain consistent cutting force at each stage. This standardized setting avoids process fluctuations caused by abrasive switching, ensuring surface texture consistency and parameter compliance rate.

[0025] Preferably, in this invention, the sawtooth cyclic method forcibly disperses system errors through multi-round cross-lapping: the three workpieces are cyclically paired so that each sealing surface serves as a reference for the other, and the errors are mutually canceled under the guidance of the tooling, ultimately achieving ultra-precise flatness matching. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the rear dynamic ring provided in an embodiment of the present invention; Figure 2 for Figure 1 Sectional view along line AA; Figure 3 A perspective view of the rear dynamic ring provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of a grinding fixture for a rear dynamic ring sealing surface provided in an embodiment of the present invention; Figure 5 for Figure 4 Sectional view along line AA; Figure 6 An assembly diagram of the grinding fixture and the rear moving ring provided in an embodiment of the present invention; Figure 7 A flowchart illustrating a grinding method for the rear dynamic ring sealing surface provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of the sawtooth loop method provided in an embodiment of the present invention.

[0027] Figure label: 1. First positioning groove; 2. Concave groove; 3. Boss structure; 4. Second positioning groove; 5. Rear moving ring; 6. End face; 5-1. Cavity bottom surface; 5-2. Sealing surface; 5-3. Boss rib. Detailed Implementation

[0028] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] As mentioned in the background section, in practical applications, due to the large sealing surface area of ​​the rear dynamic ring, grinding it on a grinding platform using general methods presents the following challenges: First, grinding a large sealing surface can easily cause wear on the grinding platform due to the high surface hardness of the parts, making it difficult to guarantee the flatness of the rear dynamic ring sealing surface to 0.003mm. Furthermore, the grinding platform requires frequent re-grinding, demanding high precision from the re-grinded platform, thus increasing processing difficulty. Second, because the materials and hardness of the parts differ from those of the grinding platform, the grinding platform is prone to wear during processing. Grinding paste remaining in the tiny gaps of the grinding platform can easily scratch the surface of the parts, making it difficult to guarantee a sealing surface roughness Ra of 0.05. Third, the parts qualification rate is only 40%, resulting in a high rework rate and unstable processing quality.

[0033] To address the aforementioned issues, this embodiment provides a grinding fixture for the rear dynamic ring sealing surface. This grinding fixture can solve the machining problem of the large sealing surface of the rear dynamic ring, ensure product quality, improve the part qualification rate, and achieve zero rework.

[0034] For example, such as Figure 1 , Figure 2 and Figure 3 As shown, this embodiment provides a grinding object for the grinding fixture—the rear moving ring 5; the front of the rear moving ring 5 is a sealing surface 5-2, the back is a cavity bottom surface 5-1, and a protruding structure protruding towards the cavity bottom surface 5-1 is provided in the middle; multiple boss ribs 5-3 are connected between the protruding structure and the outer edge; this rear moving ring 5 has 4 boss ribs 5-3; it can be seen that, in view of the problem that the sealing surface 5-2 of the rear moving ring 5 is large and difficult to process, this embodiment provides a grinding fixture for the sealing surface of the rear moving ring, such as... Figure 4 As shown, it specifically includes the tooling body; the tooling body is preferably made of SFB-2 material in polytetrafluoroethylene. This material is relatively soft and can effectively avoid scratching the surface of the rear moving ring 5 during the contact process, thus providing a basic guarantee for the grinding quality of the rear moving ring 5.

[0035] Combination Figure 5 As shown, the tooling body is arranged in a disc-shaped structure, and a circular first positioning groove 1 is opened on its end face 6. The outer edge of the rear moving ring 5 is fitted with the first positioning groove 1 with a clearance. This fitting method allows the outer edge of the rear moving ring 5 to be smoothly inserted into the first positioning groove 1, realizing the initial positioning of the rear moving ring 5 in the radial direction and preventing the rear moving ring 5 from having excessive radial displacement during the grinding process.

[0036] A concave groove 2 is formed at the center of the end face of the tooling body. The central convex structure of the rear moving ring 5 is clearance-fitted with the concave groove 2, allowing the central convex structure of the rear moving ring 5 to be embedded in the concave groove 2. Through the cooperation between the concave groove 2 and the central convex structure of the rear moving ring 5, the positioning stability of the rear moving ring 5 on the tooling is further enhanced, making it less prone to skewing during grinding and ensuring the uniformity of grinding.

[0037] In this embodiment, an annular boss structure 3 is formed between the first positioning groove 1 and the concave groove 2. Multiple second positioning grooves 4 are circumferentially formed on the boss structure 3. The number of second positioning grooves 4 matches the number of boss ribs 5-3 of the rear moving ring 5. Each boss rib 5-3 can be inserted into a corresponding second positioning groove 4. In this embodiment, four second positioning grooves 4 are used. The width of the second positioning groove 4 is designed as follows: mm, the width of the boss rib 5-3 of the rear moving ring 5 is This dimensional design, measured in mm, creates a small clearance fit, effectively reducing friction between the grinding fixture and the part, and also preventing the chemical oxide layer from peeling off the assembly surface during grinding. Simultaneously, this structural design increases the grinding clamping range, making the clamping more stable and allowing for better dimensional control during the grinding of the rear dynamic ring sealing surface. It is easier to guarantee that the surface roughness is 0.003 mm, flatness is 0.003 mm, and roughness is Ra0.05 mm.

[0038] After the rear moving ring 5 is assembled with the grinding fixture, the bottom surface 5-1 of the cavity of the rear moving ring 5 is tightly fitted with the end face 6 of the grinding fixture. This fit further ensures the stability of the rear moving ring 5 during the grinding process and avoids affecting the grinding accuracy due to loosening.

[0039] For example, the first positioning groove 1 and the end face 6 of the tooling body, the first positioning groove 1 and the boss structure 3, and both sides of the second positioning groove 4 all adopt rounded transitions, with the angle of the rounded transition being R0.5~R1. This rounded transition design can effectively avoid scratching the surface of the parts during assembly, ensuring the quality of the rear moving ring 5 from the details.

[0040] like Figure 7 As shown, this embodiment also provides a grinding method for the rear dynamic ring sealing surface. Based on the above-mentioned grinding fixture for the rear dynamic ring sealing surface, the specific steps are as follows: First, the rear moving ring 5 is subjected to a nitriding process. Nitriding treatment can improve the surface hardness and wear resistance of the rear moving ring 5, laying a good foundation for subsequent grinding processing and enabling the rear moving ring 5 to maintain good performance during long-term use.

[0041] After nitriding and before chemical oxidation, the sealing surface needs to be corrected using a surface grinder and a single-end honing machine to ensure a flatness of ≤0.008mm and a roughness of Ra0.2. This step is crucial; only when the initial state of the sealing surface meets the requirements can the final technical requirements be guaranteed during subsequent fine grinding. If the initial flatness and roughness do not meet the standards, it is difficult to compensate for them in subsequent grinding processes, which will affect the sealing performance and usability of the final rear dynamic ring 5.

[0042] For example, before grinding, such as Figure 6 As shown, the grinding fixture provided in this embodiment is assembled with the rear moving ring 5; the specific grinding stages are as follows: The first step involves using a grinding technique combining a figure-eight motion with 180° rotation. W10 diamond grinding paste is selected, and the rear moving ring sealing surface is ground on a cast iron platform to remove the chemical oxide layer. This figure-eight motion combined with 180° rotation ensures more even grinding, avoiding over- or under-grinding in certain areas. W10 diamond grinding paste has strong cutting power, quickly and effectively removing the chemical oxide layer, preparing the surface for subsequent fine grinding. During the grinding process, it is important to control the grinding force and time to ensure that only the chemical oxide layer is removed without affecting the basic dimensions and structure of the rear moving ring 5.

[0043] The second step involves grinding the parts using a figure-eight motion combined with 180° rotation, employing W7 diamond polishing paste on a glass platform. This process aims to achieve a flatness of 0.004mm and a roughness of Ra0.1 on the sealing surface. The high flatness of the glass platform provides a precise reference surface for grinding. The W7 diamond polishing paste has finer particles than W10, enabling more refined grinding and further improving the flatness and smoothness of the sealing surface. The 0.004mm flatness requirement is ensured by using a dial indicator on the platform for precise measurement. Accurate measurement allows for timely detection and adjustment of deviations during the grinding process, ensuring the desired precision is achieved.

[0044] The third step involves randomly selecting three rear moving rings 5 ​​that have undergone preliminary grinding, and then measuring the width of any one of the rear moving rings 5. The 5-3 mm boss rib is installed into the corresponding width of the lapping fixture. Within the second positioning groove 4, ensure that the bottom surface 5-1 of the cavity of the rear moving ring 5 fits against the end face 6 of the lapping fixture. This assembly process must be accurate, the boss rib 5-3 must fit properly with the second positioning groove 4, and the bottom surface 5-1 of the cavity must fit tightly against the end face 6; otherwise, the lapping accuracy will be affected.

[0045] Then, the three rear moving rings 5 ​​were machined by mutual grinding using a "serrated circulation method" and W7 diamond grinding paste. Figure 8 As shown, the specific serrated cyclic grinding process consists of three steps: S1: Install the No. 2 rear moving ring into the grinding fixture for the sealing surface of the rear moving ring, and grind the sealing surface of the No. 2 rear moving ring against the No. 1 rear moving ring. Install the No. 1 rear moving ring into the grinding fixture for the sealing surface of the rear moving ring, and grind the sealing surface of the No. 1 rear moving ring against the No. 3 rear moving ring. Install the No. 3 rear moving ring into the grinding fixture for the sealing surface of the rear moving ring, and grind the sealing surface of the No. 3 rear moving ring against the No. 2 rear moving ring.

[0046] S2: Install the No. 1 rear moving ring into the grinding fixture for the sealing surface of the rear moving ring, and grind the sealing surface of the No. 1 rear moving ring against the No. 2 rear moving ring. Install the No. 2 rear moving ring into the grinding fixture for the sealing surface of the rear moving ring, and grind the sealing surface of the No. 2 rear moving ring against the No. 3 rear moving ring. Install the No. 3 rear moving ring into the grinding fixture for the sealing surface of the rear moving ring, and grind the sealing surface of the No. 3 rear moving ring against the No. 1 rear moving ring.

[0047] S3: Install the No. 2 rear moving ring into the grinding fixture for the sealing surface of the rear moving ring, and grind the sealing surface of the No. 2 rear moving ring against the No. 3 rear moving ring. Install the No. 3 rear moving ring into the grinding fixture for the sealing surface of the rear moving ring, and grind the No. 3 rear moving ring against the No. 1 rear moving ring. Install the No. 1 rear moving ring into the grinding fixture for the sealing surface of the rear moving ring, and grind the sealing surface of the No. 1 rear moving ring against the No. 2 rear moving ring.

[0048] During the lamination process, when replacing the rear moving ring 5 installed on the lamination fixture, ensure that the sealing surface of the rear moving ring 5 is completely exposed to light before replacing it with the next one. "Completely exposed sealing surface" means that the sealing surface has been thoroughly and evenly ground, ensuring the effectiveness of the lamination. After mutual lamination, the flatness of the sealing surface of the rear moving ring 5 can be guaranteed to be 0.003mm, and the roughness can meet the technical requirement of Ra0.05. The flatness of 0.003mm is guaranteed by 100% measurement using a coordinate measuring machine (CMM). The CMM can accurately measure the flatness of the sealing surface, ensuring that each rear moving ring 5 meets the requirements. The roughness Ra0.05 is guaranteed by 100% measurement using a roughness tester. The roughness tester can accurately measure the roughness value of the sealing surface, providing reliable inspection data for the quality of the rear moving ring 5.

[0049] After the grinding process is completed, the sealing surface of the precision-ground rotating ring 5 is polished on a φ125×50mm felt wheel to obtain the well-ground rotating ring 5. The felt wheel is soft and will not scratch the sealing surface during the polishing process, which can further improve the smoothness of the sealing surface and make it smoother, thus improving the sealing performance of the rotating ring 5.

[0050] Finally, the ground rear rotating ring 5 undergoes a series of cleaning, testing, and oil-sealing processes. The cleaning process removes residual grinding paste, metal shavings, and other impurities from the surface of the rear rotating ring 5, preventing these impurities from affecting its use and the accuracy of subsequent testing. The testing process performs a final inspection of the various performance indicators of the rear rotating ring 5 to ensure it meets design requirements. The oil-sealing process prevents corrosion of the rear rotating ring 5 during storage and transportation, ensuring that its quality remains unaffected.

[0051] By combining the aforementioned grinding fixtures and methods, the processing difficulties of wear on the grinding platform and easy scratching of the sealing surface caused by differences in materials and hardness during surface grinding are eliminated. This achieves efficient grinding of the large sealing surface of the rear dynamic ring with stable and reliable processing quality. Furthermore, the use of a three-part mutual grinding method increases the processing efficiency by three times, significantly improving production efficiency while ensuring quality, demonstrating significant practical application value.

[0052] Therefore, the grinding fixture and method for the rear dynamic ring sealing surface provided by the present invention has the following advantages compared with existing grinding methods: First, this grinding fixture is easy to clamp, stable, reliable, and easy to operate; Secondly, the use of this grinding fixture and method can ensure stable part processing quality and meet the dimensional requirements of the design drawings; Third, by using this grinding fixture and method, the first-pass yield of parts can be increased to 100%, achieving zero rework.

[0053] Fourth, using this grinding fixture and method can increase processing efficiency by 3 times.

[0054] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A grinding fixture for the rear dynamic ring sealing surface, characterized in that, include: Tooling body; The tooling body is arranged in a disc-shaped structure, and a circular first positioning groove (1) is opened on the end face (6). The outer edge of the rear moving ring (5) is in clearance fit with the first positioning groove (1), and the outer edge of the rear moving ring (5) can be inserted into the first positioning groove (1). The tool body has a concave groove (2) at the center of its end face. The central convex structure of the rear moving ring (5) is in clearance fit with the concave groove (2). The central convex structure of the rear moving ring (5) can be embedded in the concave groove (2). The front of the rear moving ring (5) is the sealing surface (5-2), the back is the bottom surface of the cavity (5-1), and a protruding structure protruding towards the bottom surface of the cavity (5-1) is provided in the middle; four boss ribs (5-3) are connected between the protruding structure and the outer edge. A ring-shaped boss structure (3) is formed between the first positioning groove (1) and the concave groove (2). Four second positioning grooves (4) are provided on the boss structure (3) along the circumferential direction. The number of the second positioning grooves (4) matches the number of boss ribs (5-3) of the rear moving ring (5). Each boss rib (5-3) can be inserted into the corresponding second positioning groove (4). The width of the second positioning groove (4) is designed as follows: mm, the width of the boss rib (5-3) of the rear moving ring (5) is mm; After the rear moving ring (5) is assembled with the grinding fixture, the bottom surface (5-1) of the cavity of the rear moving ring (5) is in close contact with the end face (6) of the grinding fixture; The first positioning groove (1) and the end face (6) of the tooling body, the first positioning groove (1) and the boss structure (3), and both sides of the second positioning groove (4) are all rounded. The angle of the arc transition is R0.5~R1; where R is the radius of the arc. The tooling body is made of SFB-2 from polytetrafluoroethylene.

2. A grinding method for the rear dynamic ring sealing surface, characterized in that, A grinding fixture for a rear dynamic ring sealing surface according to claim 1 includes: A grinding technique combining figure-eight motion and 180° rotation is used to grind the rear moving ring sealing surface on a cast iron platform to remove the chemical oxide layer on the sealing surface; wherein, the grinding motion of the rear moving ring is driven by a grinding fixture on the rear moving ring sealing surface. A grinding technique combining figure-eight motion and 180° rotation is used to grind the sealing surface of the rear moving ring on a glass platform to obtain a pre-ground rear moving ring. Three pre-ground moving rings were randomly selected, and a sawtooth cyclic method was used to perform mutual grinding on the two pre-ground moving rings to obtain a finely ground moving ring; during the grinding process, any one of the moving rings was installed into a grinding fixture for the sealing surface of the moving ring.

3. The grinding method for the rear dynamic ring sealing surface according to claim 2, characterized in that, The process of randomly selecting three pre-ground moving rings and using a sawtooth cyclic method to perform pairwise mutual grinding of the pre-ground moving rings further includes: The sealing surface of the precision-ground rotating ring is polished on a felt wheel to obtain a well-ground rotating ring.

4. The grinding method for the rear dynamic ring sealing surface according to claim 3, characterized in that, Before grinding the rear moving ring sealing surface on the cast iron platform using the figure-eight motion combined with 180° rotation, the grinding method also includes: The rear dynamic ring is subjected to nitriding treatment; After polishing the sealing surface of the precision-ground rotating ring on a felt wheel, the process further includes: The ground rear rotating ring is then cleaned, inspected, and oil-sealed in sequence.

5. The grinding method for the rear dynamic ring sealing surface according to claim 2, characterized in that, The grinding method, which combines figure-eight motion with 180° rotation, involves grinding the rear dynamic ring sealing surface on a cast iron platform using W7~W10 diamond grinding paste. The grinding technique, which combines figure-eight motion with 180° rotation, grinds the rear dynamic ring sealing surface of the chemical oxide layer on a glass platform using W7~W10 diamond grinding paste. The process involves randomly selecting three pre-grinding moving rings and using a sawtooth cyclic method to perform pairwise mutual grinding on the pre-grinding moving rings. W7~W10 diamond grinding paste is used to perform pairwise mutual grinding on the pre-grinding moving rings.

6. The grinding method for the rear dynamic ring sealing surface according to claim 2, characterized in that, The process involves randomly selecting three pre-ground moving rings and using a sawtooth-shaped cyclic method to perform pairwise mutual grinding of the pre-ground moving rings, including: From all the pre-grinding moving rings, three were randomly selected and designated as No. 1, No. 2, and No. 3; the cyclic grinding process was divided into three steps: first step: Insert No. 2 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 1 against No.

2. Insert No. 1 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 1 against No.

3. Insert No. 3 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 2 with No.

3. Step Two: Insert No. 1 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 1 against No.

2. Insert No. 2 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 2 against No.

3. Insert No. 3 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 1 against No.

3. Step 3: Insert No. 2 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 2 against No.

3. Insert No. 3 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 1 against No.

3. Insert No. 1 into the grinding fixture for the sealing surface of the rear dynamic ring, and grind the sealing surface of No. 1 against No. 2.

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