Method for optimizing sealing performance of a ball-cone joint

Abstract

The application discloses a kind of ball head-cone joint sealing performance optimization methods, comprising: combing and analyzing the design factors that influence ball-cone joint sealing performance, the design factors include sealing torque, bellows stiffness and sealing pair size;The numerical value of bellows consumption sealing torque is obtained by analyzing and testing bellows stiffness;Establish the mechanical model of ball-cone seal, analyze the structure parameters that influence sealing performance, the structure parameters are the spherical radius, cone angle and tangent circle diameter in sealing pair size;According to the influence of simulation analysis on sealing performance according to structure parameter;Carry out simplified piece verification test, establish the correlation between minimum sealing torque of simplified piece and spherical radius and cone angle;The correlation between minimum sealing torque of product state and spherical radius and cone angle is obtained, and the optimized spherical radius and cone angle are obtained to carry out product piece verification test.The method can improve sealing performance and greatly shorten the development cycle.

Description

Technical Field

[0001] This invention relates to the field of pipeline sealing structure technology, specifically to a method for optimizing the sealing performance of a ball-head-cone joint. Background Technology

[0002] Sealing technology is an important research area in modern science and technology. High-pressure gas testing chambers and similar facilities often use small-diameter pipes as connection pathways between fluid devices. These pipes are small in size, transport high-pressure media, and require stringent sealing performance and high reliability. Furthermore, due to space constraints, the "flange-gasket" sealing structure commonly used in large pipelines cannot be employed for sealing connections in small-diameter pipes. Ball-cone joints, with their compact structure, easy assembly and disassembly, good versatility, and reliable sealing, can achieve sealing connections in small-diameter pipes. Since the ball-cone joint is a weak point leading to leakage, ensuring its sealing performance is crucial for the reliability of the entire piping system during its service life.

[0003] like Figure 1 As shown, the ball-cone seal mainly consists of three components: a ball assembly 1, a cone assembly 2, and a nut 3. To achieve a higher double sealing effect, a bellows 4 is welded between the nut and the cone assembly. The cone assembly has external threads on the outside and a conical surface on the inside, while the ball assembly has a spherical surface. When the nut is tightened onto the external threads on the cone assembly, the nut will move the ball assembly, causing the spherical surface to contact the cone surface. The contact surfaces will undergo stress deformation, thus forming a sealing ring to prevent gas or liquid leakage.

[0004] This type of ball-cone seal has a compact structure and numerous welds, making it susceptible to various factors affecting manufacturing quality. These factors include precision machining, bellows welding, overall welding deformation control, and precise control of the sealing surface shape and position. The manufacturing process is challenging, resulting in a low leak detection pass rate. Traditional methods rely on experience for design and manufacturing optimization, leading to long development cycles and limited optimization effectiveness. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of traditional optimization methods for ball-cone seal structures by providing a method for optimizing the sealing performance of ball-head-cone joints. The ball-cone joint optimized using this method not only has better sealing performance but also significantly reduces the sensitivity of its sealing performance to various manufacturing uncertainties. It has the advantages of simple method and high efficiency in research and development iteration, and is suitable for the development of ball-cone seal structures for pipelines in high-pressure fluid systems.

[0006] This invention is achieved through the following technical solution: This invention provides a method for optimizing the sealing performance of a ball-head-cone joint, comprising: Step 1: Identify and analyze the design factors that affect the sealing performance of the ball-cone joint, including sealing torque, bellows stiffness, and sealing pair dimensions; Step 2: Analyze and test the stiffness of the bellows to obtain the sealing torque consumed by the bellows; Step 3: Establish a mechanical model of the ball-cone seal and theoretically analyze the structural parameters that affect the sealing performance. The structural parameters are the spherical radius, conical angle, and tangent circle diameter in the dimensions of the sealing pair. Step 4: Conduct simulation analysis based on structural parameters to verify the impact on sealing performance; Step 5: Based on theoretical and simulation analysis, conduct simplified part verification tests to establish the relationship between the minimum sealing torque and the spherical radius, conical angle, and tangent circle diameter under simplified part conditions; Step 6: Based on the sealing torque consumed by the bellows, obtain the relationship between the minimum sealing torque under product conditions and the spherical radius, conical angle, and tangent circle diameter, and obtain the optimized spherical radius, conical angle, and tangent circle diameter, and conduct product verification tests accordingly.

[0007] As a further aspect of the present invention, the corrugated pipe stiffness includes axial stiffness and torsional stiffness. The axial stiffness and torsional stiffness of the corrugated pipe can be obtained by theoretical calculation and verified by actual measurement through compression test and torsion test.

[0008] As a further aspect of the present invention, the theoretical formula for calculating the axial stiffness of the bellows is as follows: ; In the formula: E is the elastic modulus, D m d1 is the mean diameter of the bellows, t is the thickness of the bellows diaphragm, n is the number of bellows, h is the depth of the bellows, d1 is the inner diameter of the bellows, and d2 is the outer diameter of the bellows.

[0009] As a further aspect of the present invention, the theoretical formula for calculating the torsional stiffness of the bellows is as follows: ; In the formula: R m R is the average radius of the bellows, t is the thickness of the bellows diaphragm, n is the wavenumber of the bellows, v is Poisson's ratio, h is the depth of the bellows, and R c R is the crest radius. r The radius of the trough.

[0010] As a further aspect of the present invention, the sealing torque consumed by the bellows can be obtained by calculating the torque value consumed by the bellows torsion based on the torsional stiffness of the bellows and the maximum torsional angle of the bellows when forming a seal.

[0011] As a further aspect of the present invention, in step three, based on Hertzian contact theory, a mechanical model of the ball-cone seal is established as follows: ; In the formula: P is the sealing specific pressure, W is the sealing surface width, F is the axial clamping force, R is the radius of the sphere, A is the cone angle, and D is the diameter of the tangent circle.

[0012] As a further aspect of the present invention, in step four, during the simulation analysis, the spherical radius, conical angle, and tangent circle diameter are optimized with the goal of reducing the minimum sealing torque, and the sealing structure performance before and after optimization is analyzed by finite element simulation.

[0013] As a further aspect of the present invention, in step five, the bellows structure is ignored when conducting the simplified part verification test, and based on the simplified part test results, a data fitting method is used to establish the correlation between the minimum sealing torque and the spherical radius, conical angle, and tangent circle diameter under the simplified part condition: ; In the formula: T min Let A be the minimum sealing torque, R be the cone angle, D be the spherical radius, K be the diameter of the tangent circle, K be the proportionality coefficient, α be the power exponent of A, β be the power exponent of R, and χ be the power exponent of D.

[0014] As a further aspect of the present invention, the relationship between the minimum sealing torque in the product state in step six and the spherical radius, conical angle, and tangent circle diameter is as follows: T 产品min = T 简化min + T 波纹管 ; In the formula: T 产品min The minimum sealing torque for the product, T 简化min To simplify the minimum sealing torque of the component, T 波纹管 The sealing torque consumed by the bellows.

[0015] As a further aspect of the present invention, in step six, based on the relationship between the minimum sealing torque under the product condition and the spherical radius, conical angle, and tangent circle diameter, and combined with the establishment of a mechanical model of the ball-cone seal, the optimized spherical radius, conical angle, and tangent circle diameter can be obtained.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention analyzes the design factors affecting the sealing performance of ball-cone joints and conducts analysis and testing of bellows stiffness. Simultaneously, it constructs a ball-cone seal contact mechanics model and establishes a rapid optimization iteration mode based on theory, simulation, and simplified component testing. The ball-cone joint optimized using the method described in this invention not only exhibits better sealing performance but also significantly reduces the sensitivity of its sealing performance to various manufacturing uncertainties. It boasts advantages such as simple method and the ability to substantially shorten the ball-cone joint development cycle, making it suitable for the development of ball-cone sealing structures for pipelines in high-pressure fluid systems. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the ball-head-cone joint seal in this invention; Figure 2 This is a schematic diagram illustrating the impact of design factors on sealing performance in this invention; Figure 3 This is the axial stiffness curve of the bellows in this invention; Figure 4 This is the torsional stiffness curve of the bellows in this invention; Figure 5 This is a finite element simulation diagram of the ball-cone seal in this invention; Figure 6 This is a simplified schematic diagram of the test specimen used in this invention; Figure 7 This is a diagram illustrating the effect of sealing pair dimensions on sealing performance in a simplified experiment of this invention; Figure 8 This is a flowchart of the method for optimizing the sealing performance of the ball-head-conical joint in this invention.

[0018] The attached diagram shows the markings and corresponding component names: 1-Spherical assembly, 2-Conical assembly, 3-Nut, 4-Bellwall. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0021] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly indicating the number, specific order, or primary and secondary relationship of the indicated technical features.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0024] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0025] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces), unless otherwise explicitly specified.

[0026] In the description of the embodiments of this application, the technical 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 only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0027] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0028] like Figure 1 The ball-cone seal structure shown is widely used in high-pressure gas laboratories and other fields where tight sealing is required, making it a weak point in pipeline systems prone to leakage. Due to widespread uncertainties in manufacturing and assembly, uncertainties in sealing performance are unavoidable, thus reducing the reliability of pipeline systems in harsh environments. Traditionally, ball-cone joint design and manufacturing optimization mainly rely on experience, resulting in long development cycles and limited optimization effects.

[0029] In view of this, the applicant proposes a sealing performance optimization method that can effectively solve the above-mentioned design and manufacturing problems. It can be used in the sealing structure of high-pressure fluid systems in pipeline systems and other fields. The method establishes the relationship between design and manufacturing parameters and sealing performance, and optimizes structural parameters such as cone angle and spherical radius to improve the robustness of sealing performance. The optimized ball-cone joint not only has better sealing performance, but also greatly reduces the sensitivity of sealing performance to various manufacturing uncertainties.

[0030] Please refer to Figures 1 to 8 The present application provides a method for optimizing the sealing performance of a ball-head-cone joint, comprising: Step 1: Identify and analyze the design factors that affect the sealing performance of the ball-cone joint, including sealing torque, bellows stiffness, and sealing pair dimensions; Step 2: Analyze and test the stiffness of the bellows to obtain the sealing torque consumed by the bellows; Step 3: Establish a mechanical model of the ball-cone seal and theoretically analyze the structural parameters that affect the sealing performance. The structural parameters are the spherical radius, cone angle, and tangent circle diameter in the dimensions of the sealing pair. Step 4: Conduct simulation analysis based on structural parameters to verify the impact on sealing performance; Step 5: Based on theoretical and simulation analysis, conduct simplified part verification tests to establish the relationship between the minimum sealing torque and the spherical radius, conical angle, and tangent circle diameter under simplified part conditions; Step 6: Based on the sealing torque consumed by the bellows, obtain the relationship between the minimum sealing torque under product conditions and the spherical radius, conical angle, and tangent circle diameter, and obtain the optimized spherical radius, conical angle, and tangent circle diameter, and conduct product verification tests accordingly.

[0031] This application outlines and analyzes the design influencing factors of ball-head-cone seal performance, such as... Figure 2 As shown, the main factors are axial force and three other factors. The influence of each key element on sealing performance is analyzed. Increasing the sealing torque can improve the sealing specific pressure and sealing surface width. If the sealing torque is increased to a certain level to meet basic requirements, the pass rate can be significantly improved. However, increasing the sealing torque will affect the lifespan of the bellows, and consequently, the opening and closing lifespan of the ball cone seal.

[0032] According to some embodiments of this application, the corrugated pipe stiffness includes axial stiffness and torsional stiffness. The axial stiffness and torsional stiffness of the corrugated pipe can be obtained by theoretical calculation and verified by actual measurement through compression test and torsion test.

[0033] According to some embodiments of this application, the theoretical formula for calculating the axial stiffness of the bellows is as follows: ; (1) In the formula: E is the elastic modulus, D m d1 is the median diameter of the bellows, t is the thickness of the bellows diaphragm, n is the wave number of the bellows, h is the depth of the bellows, d1 is the inner diameter of the bellows, and d2 is the outer diameter of the bellows.

[0034] From the force transmission process of the sealing action of the ball-cone joint, it can be seen that the bellows is an important link. Therefore, the axial stiffness of the bellows was theoretically analyzed. Substituting the corresponding parameters into equation (1), the estimated axial stiffness of the bellows was about 74 N / mm, and the maximum axial displacement of the bellows was about 0.6 mm. The axial stiffness was also measured by compression test, which was consistent with the theoretical analysis.

[0035] The axial force-displacement test curves of bellows samples S1 and S2 are as follows: Figure 3 As shown, the maximum moving distance is 0.6 mm, the axial force is less than 40 N, and the axial stiffness of the bellows has little impact on the sealing performance.

[0036] According to some embodiments of this application, the theoretical formula for calculating the torsional stiffness of the bellows is as follows: ; (2) In the formula: R m R is the average radius of the bellows, t is the thickness of the bellows diaphragm, n is the wavenumber of the bellows, v is Poisson's ratio, h is the depth of the bellows, and R c R is the crest radius. r The radius of the trough.

[0037] According to some embodiments of this application, the sealing torque consumed by the bellows can be obtained by calculating the torque value consumed by the bellows torsion based on the torsional stiffness of the bellows and the maximum torsional angle of the bellows when forming a seal.

[0038] During the tightening of the nut, the bellows will experience a certain axial displacement and a certain torsional angle. The torsion of the bellows will consume a certain amount of torque, which means a certain amount of sealing torque will be consumed.

[0039] Substituting the relevant parameters into equation (2), the estimated torsional stiffness of the bellows is approximately 53 Nm / rad, the maximum torsional angle of the bellows is approximately 1.5°, and the calculated torque consumed by the bellows during torsion is approximately 1.4 Nm. The torsional stiffness was measured through torsion tests and is consistent with the theoretical analysis. The torsional moment-rotation angle test curves of bellows samples S1, S2, and S3 are shown below. Figure 4 As shown.

[0040] According to some embodiments of this application, in step three, based on Hertzian contact theory, a mechanical model of the ball-cone seal is established as follows: ; (3) ; (4) In the formula: P is the sealing specific pressure, W is the sealing surface width, F is the axial clamping force, R is the radius of the sphere, A is the cone angle, and D is the diameter of the tangent circle.

[0041] The sealing torque is converted into an axial clamping force due to the relative motion of the ball assembly and the cone assembly. The spherical surface of the ball assembly contacts the conical surface of the cone assembly, forming a ball-cone sealing surface (e.g., Figure 1 (As shown). According to theoretical analysis, the spherical radius of the sphere assembly, the conical angle of the cone assembly, and the tangent circle diameters of the sphere and cone assemblies are the main structural parameters affecting the sealing performance. The relationship between the sealing specific pressure (i.e., contact stress) and sealing surface width of the ball-cone seal and the dimensions of the sealing pair is shown in formulas (3, 4).

[0042] According to the mechanical model of the ball-cone seal, the sealing specific pressure is inversely proportional to the radius of the sphere, the angle of the cone, and the diameter of the tangent circle. The sealing surface width is inversely proportional to the angle of the cone and the diameter of the tangent circle, and directly proportional to the radius of the sphere.

[0043] With the ball-cone seal structure unchanged, the main dimensions affecting sealing performance are the spherical radius, the cone angle, and the tangent circle diameter. When the existing joint structure has limitations, the optimization range of the tangent circle diameter is limited. Furthermore, to minimize changes, the tangent circle diameter can be kept constant (i.e., the tangent point and sealing position remain unchanged), optimizing only the spherical radius and cone angle. The theoretical analysis above shows that reducing the spherical radius and cone angle can increase the sealing specific pressure; however, if the spherical radius is too small, the sealing surface width will be significantly reduced, deteriorating the sealing performance.

[0044] According to some embodiments of this application, in step four, during simulation analysis, the spherical radius, conical angle, and tangent circle diameter are optimized with the goal of reducing the minimum sealing torque, and the sealing structure performance before and after optimization is analyzed by finite element simulation.

[0045] With the ball-cone seal structure unchanged, the main dimensions affecting sealing performance are the radius of the sphere, the angle of the cone, and the diameter of the tangent circle. Reducing the radius of the sphere increases the sealing specific pressure. Reducing the angle of the cone increases the normal pressure of the sealing pair, thereby increasing the sealing specific pressure.

[0046] The spherical radius, cone angle, and tangent circle diameter were optimized to minimize the sealing torque. Finite element simulation analysis was performed on the sealing structure before and after optimization, yielding the same influence trend as the theoretical analysis, both indicating that the optimized structure can effectively improve the sealing performance. The finite element simulation results of the ball-cone seal are as follows: Figure 5 As shown.

[0047] To quickly verify the theoretical analysis, a simplified experimental specimen (such as...) was designed. Figure 6 (As shown). Based on theoretical and simulation analysis, this application conducted simplified component verification experiments ignoring the bellows structure to facilitate rapid optimization and iteration. The influence of the sealing pair dimensions on the sealing performance was verified using the simplified test piece, as shown below. Figure 7 As shown in the results, under the simplified part condition: reducing the radius of the sphere and reducing the angle of the cone both contribute to sealing. The experimental results are consistent with the theoretical analysis trend.

[0048] According to some embodiments of this application, in step five, the bellows structure is ignored when conducting simplified part verification tests. Based on the simplified part test results, the generalized Taylor formula method is used to establish a high-order nonlinear relationship between input and output quantities. The fitting result is shown in equation (5). That is, by using data fitting, the relationship between the minimum sealing torque and the spherical radius, conical angle, and tangent circle diameter under simplified part conditions is established: ; (5) In the formula: T min Let A be the minimum sealing torque, R be the cone angle, D be the spherical radius, K be the diameter of the tangent circle, K be the proportionality coefficient, α be the power exponent of A, β be the power exponent of R, and χ be the power exponent of D.

[0049] According to equation (5), the cone angle has a greater impact on sealing performance (minimum sealing torque) than the spherical radius. The trend of the fitted equation (5) is consistent with the trend of the theoretical analysis equation (3). Based on the theoretical analysis and the fitted equation, we can guide the optimization selection of the sealing dimensions of subsequent products.

[0050] Since theoretical analysis and simplified component verification show that reducing the spherical radius / conical angle can improve sealing performance, experiments can be planned to optimize the spherical radius, conical angle, and both the spherical radius and conical angle to verify the improvement in product-level pass rate.

[0051] According to some embodiments of this application, the relationship between the minimum sealing torque in the product state in step six and the spherical radius, conical angle, and tangent circle diameter is as follows: T 产品min = T 简化min + T 波纹管 ; (6) In the formula: T 产品min The minimum sealing torque for the product, T 简化min To simplify the minimum sealing torque of the component, T 波纹管 The sealing torque consumed by the bellows.

[0052] Based on the test results of the simplified part, this application uses a data fitting method to establish the correlation between the minimum sealing torque of the simplified part and the spherical radius, conical angle, and tangent circle diameter. Then, the correlation between the minimum sealing torque of the product state and the spherical radius, conical angle, and tangent circle diameter can be calculated through the sealing torque consumed by the bellows. In other words, the sealing torque estimate of the product state can be obtained by adding the minimum sealing torque of the simplified part to the sealing torque consumed by the bellows.

[0053] According to some embodiments of this application, in step six, based on the relationship between the minimum sealing torque in the product state and the spherical radius, conical angle, and tangent circle diameter, and combined with the establishment of a mechanical model of the ball-cone seal, the optimized spherical radius, conical angle, and tangent circle diameter can be obtained.

[0054] By obtaining the relationship between the minimum sealing torque and the spherical radius, conical angle, and tangent circle diameter under the product condition, we can obtain the desired optimized spherical radius, conical angle, and tangent circle diameter. Furthermore, through product production verification, we can further refine the relationship between the minimum sealing torque and the spherical radius, conical angle, and tangent circle diameter under the product condition, providing support for other optimization conditions.

[0055] Specifically, the objective function aims to find the optimal combination of the cone angle A, the spherical radius R, and the tangent circle diameter D, minimizing the minimum sealing torque in the product state (a smaller sealing torque corresponds to a longer product lifespan). Simultaneously, the design must satisfy two constraints: first, the sealing specific pressure must not be lower than the minimum pressure requirement; second, the sealing surface width must not be lower than the minimum width requirement. The minimum sealing torque in the product state equals the sealing torque in the simplified part state plus the sealing torque consumed by the bellows. The objective function and constraints are as follows: Objective function: ; In the formula, T obj Let be the objective function. T 产品min This is the minimum sealing torque for the product.

[0056] Constraints: ; In the formula: P min For minimum sealing pressure, W min Where F is the minimum sealing surface width, R is the axial clamping force, A is the radius of the sphere, D is the cone angle, and k is the diameter of the tangent circle. p k is the sealing pressure correction factor. w This is a correction factor for the width of the sealing surface. T 产品min The minimum sealing torque for the product, T 简化min To simplify the minimum sealing torque of the component, K 简化 To simplify the proportionality coefficients, α is the power exponent of A, β is the power exponent of R, and χ is the power exponent of D. T 波纹管 The sealing torque consumed by the bellows.

[0057] By verifying the product during production and correcting the relationship between the minimum sealing torque and the cone angle, spherical radius, and tangent circle diameter in the product state, the minimum sealing torque of the product can be designed as needed.

[0058] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for optimizing the sealing performance of a ball-head-conical joint, characterized in that, include: Step 1: Identify and analyze the design factors that affect the sealing performance of the ball-cone joint, including sealing torque, bellows stiffness, and sealing pair dimensions; Step 2: Analyze and test the stiffness of the bellows to obtain the sealing torque consumed by the bellows; Step 3: Establish a mechanical model of the ball-cone seal and theoretically analyze the structural parameters that affect the sealing performance. The structural parameters are the spherical radius, conical angle, and tangent circle diameter in the dimensions of the sealing pair. Step 4: Conduct simulation analysis based on structural parameters to verify the impact on sealing performance; Step 5: Based on theoretical and simulation analysis, conduct simplified part verification tests to establish the relationship between the minimum sealing torque and the spherical radius, conical angle, and tangent circle diameter under simplified part conditions; Step 6: Based on the sealing torque consumed by the bellows, obtain the relationship between the minimum sealing torque under product conditions and the spherical radius, conical angle, and tangent circle diameter, and obtain the optimized spherical radius, conical angle, and tangent circle diameter, and conduct product verification tests accordingly.

2. The method for optimizing the sealing performance of a ball-head-conical joint according to claim 1, characterized in that, The bellows stiffness includes axial stiffness and torsional stiffness. The axial stiffness and torsional stiffness of the bellows can be obtained through theoretical calculations and verified by actual measurement through compression tests and torsion tests.

3. The method for optimizing the sealing performance of a ball-head-conical joint according to claim 2, characterized in that, The theoretical formula for calculating the axial stiffness of the bellows is as follows: ； In the formula: E is the elastic modulus, D m d1 is the mean diameter of the bellows, t is the thickness of the bellows diaphragm, n is the number of bellows, h is the depth of the bellows, d1 is the inner diameter of the bellows, and d2 is the outer diameter of the bellows.

4. The method for optimizing the sealing performance of a ball-head-conical joint according to claim 2, characterized in that, The theoretical formula for calculating the torsional stiffness of the bellows is as follows: ； In the formula: R m R is the average radius of the bellows, t is the thickness of the bellows diaphragm, n is the wavenumber of the bellows, v is Poisson's ratio, h is the depth of the bellows, and R c R is the crest radius. r The radius of the trough.

5. The method for optimizing the sealing performance of a ball-head-conical joint according to claim 1, characterized in that, The sealing torque consumed by the bellows can be obtained by calculating the torque value consumed by the bellows torsion based on the torsional stiffness of the bellows and the maximum torsional angle of the bellows when forming a seal.

6. The method for optimizing the sealing performance of a ball-head-conical joint according to claim 1, characterized in that, In step three, based on Hertzian contact theory, the mechanical model of the ball-cone seal is established as follows: ； In the formula: P is the sealing specific pressure, W is the sealing surface width, F is the axial clamping force, R is the radius of the sphere, A is the cone angle, and D is the diameter of the tangent circle.

7. The method for optimizing the sealing performance of a ball-head-conical joint according to claim 1, characterized in that, In step four, during the simulation analysis, the spherical radius, conical angle, and tangent circle diameter are optimized with the goal of reducing the minimum sealing torque. Finite element simulation analysis is then performed on the sealing structure performance before and after optimization.

8. The method for optimizing the sealing performance of a ball-head-conical joint according to claim 1, characterized in that, In step five, the bellows structure is ignored when conducting simplified part verification tests. Based on the simplified part test results, a data fitting method is used to establish the relationship between the minimum sealing torque and the spherical radius, conical angle, and tangent circle diameter under the simplified part condition: ； In the formula: T min Let A be the minimum sealing torque, R be the cone angle, D be the spherical radius, K be the diameter of the tangent circle, K be the proportionality coefficient, α be the power exponent of A, β be the power exponent of R, and χ be the power exponent of D.

9. The method for optimizing the sealing performance of a ball-head-conical joint according to claim 8, characterized in that, The relationship between the minimum sealing torque in the product state in step six and the spherical radius, conical angle, and tangent circle diameter: T 产品min = T 简化min + T 波纹管 ； In the formula: T 产品min The minimum sealing torque for the product, T 简化min To simplify the minimum sealing torque of the component, T 波纹管 The sealing torque consumed by the bellows.

10. The method for optimizing the sealing performance of a ball-head-conical joint according to claim 9, characterized in that, In step six, based on the relationship between the minimum sealing torque under product conditions and the spherical radius, conical angle, and tangent circle diameter, and by establishing a mechanical model of the ball-cone seal, the optimized spherical radius, conical angle, and tangent circle diameter can be obtained.

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