Elastic constraint flexible joint structure

Abstract

The invention relates to an elastic constraint flexible joint structure which comprises a cross beam connecting part and a joint base body, and four groups of symmetrically distributed steel ball constraint mechanisms are arranged between the cross beam connecting part and the joint base body to form composite connection with radial rigidity and axial elastic compensation. A top bead screw elastic assembly with a pre-pressing spring is arranged outside the steel ball restraining mechanism, the diameter difference between a positioning pin in the center of the joint base body and a pin hole is 1-2 mm, and a gap is compensated by the steel ball restraining mechanism. The assemblies such as the top ball screw elastic assembly and the steel ball restraining mechanism have specific parameter requirements. The structure is further provided with a dynamic balance monitoring module, the installation face of the cross beam connecting part is provided with a wear-resistant coating, and multiple dynamic response indexes are met. The assembling method comprises the steps of liquid nitrogen freezing assembling of the positioning pin, calibration of the symmetry degree of the steel ball restraining mechanism through the laser interferometer, three times of incremental screwing of the top ball screw set and the like.

Description

Technical Field

[0001] The present application relates to the technical field of mechanical connection and structural stability, and in particular to an elastically constrained flexible joint structure. Background Art

[0002] In the field of mechanical connection and structural stability technology, traditional connection methods and structural designs have many limitations and are difficult to meet the requirements of modern industry for high precision, high stability and high reliability. In terms of power transmission and structural fixation, many designs are difficult to effectively constrain the offset position during operation, which makes the system prone to motion overshoot when moving at high speed or under sudden loads. Once overshoot occurs, the structure is easily damaged, which seriously affects the system's overload resistance and overall stability.

[0003] In addition, the traditional structure has extremely high requirements for processing accuracy, which not only greatly increases the production cost, but also increases the difficulty of processing. In practical applications, due to the influence of factors such as material properties and temperature changes, the two sides of the beam often have asynchronous problems. However, it is difficult for traditional structures to achieve flexible connections to effectively offset this length change, resulting in the accuracy being easily affected by gap changes during high-speed movement.

[0004] More importantly, existing technologies perform poorly in handling dynamic loads and compensating for small displacements. The lack of an effective elastic compensation mechanism makes the structure prone to fatigue damage during long-term use, reducing the service life of the system. At the same time, it is difficult for traditional structures to achieve precise fine-tuning and dynamic balance, which is particularly prominent in application scenarios that require high-precision positioning. Existing technologies have problems such as insufficient wear resistance and slow dynamic response. Under high-frequency and long-term operating conditions, the performance of the structure decays rapidly and it is difficult to maintain long-term stability. In addition, the lack of an effective monitoring and feedback mechanism makes it difficult for the system to adjust and optimize the operating status in a timely manner. In response to the above problems, existing technologies are in urgent need of improvement. Summary of the invention

[0005] The purpose of the present application is to provide an elastically constrained flexible joint structure, which has the advantages of improving structural stability, enhancing overload resistance, achieving precise fine-tuning and dynamic balance, extending service life, and improving wear resistance and dynamic response speed.

[0006] The present application provides an elastically constrained flexible joint structure, and the technical solution is as follows: it comprises a crossbeam connecting portion and a joint base that cooperate with each other, and four groups of symmetrically distributed steel ball constraint mechanisms are arranged between the joint base and the crossbeam connecting portion to form a composite connection structure of radial rigid constraint and axial elastic compensation; an axially arranged top ball screw elastic component is arranged on the periphery of the steel ball constraint mechanism, which has a built-in pre-stressed spring and is coaxially installed with the axis of the crossbeam; a locating pin clearance matching structure is provided in the center of the joint base, comprising a locating pin and a pin hole with a diameter difference of 1-2mm, and the gap between the two is offset compensated by the steel ball constraint mechanism.

[0007] Furthermore, the present application also proposes that the ball screw elastic assembly includes a plunger sleeve, a compensation spring and a preload adjustment screw, wherein the stiffness coefficient K of the compensation spring satisfies: 10N / mm≤K≤30N / mm; and the adjustable range of the spring pre-compression is 2-5mm, and the maximum stroke compensation amount is ≥3mm.

[0008] Furthermore, the present application also proposes that the four groups of steel ball constraint mechanisms are arranged at four quadrant points of the joint base in orthogonal directions, and each group contains two precision steel balls with a diameter tolerance of ≤0.005mm. The gap is fine-tuned by differential locking screws, and the adjustment accuracy reaches 0.01mm.

[0009] Furthermore, the present application also proposes that the differential set screw has a double thread structure, including an external thread portion and an internal push cone surface, and the thread lead difference is designed to be 0.5 mm / turn, thereby realizing nano-level displacement adjustment of the steel ball.

[0010] Furthermore, the present application also proposes that the fit between the locating pin and the pin hole satisfies: 0.8mm≤Dhole-Dpin≤1.5mm and a spherical contact portion is provided at the end of the locating pin, and its curvature radius R and the steel ball diameter d satisfy: R=1.2d±0.1mm.

[0011] Furthermore, the present application also proposes that the constraint contact surface of the joint matrix adopts a gradient heat treatment process, the surface hardness is HRC62±2, the core hardness is maintained at HRC35-40, and the hardened layer depth is 0.3-0.5mm.

[0012] Furthermore, the present application also proposes that it also includes a dynamic balance monitoring module, which is equipped with: a strain sensor embedded in the joint base, detecting the offset ε and satisfying: |ε|≤0.15mm; a pressure sensor arranged in the ball screw assembly, monitoring the spring force fluctuation ΔF and satisfying: |ΔF / F0|≤5% where F0 is the initial preload.

[0013] Furthermore, the present application also proposes that the mounting surface of the beam connection portion is provided with a laser cladding wear-resistant coating, the coating composition is WC-12Co, the thickness is 0.2-0.3mm, and the surface roughness Ra≤0.4μm.

[0014] Furthermore, the present application also proposes that the structure meets the dynamic response indicators: axial elastic compensation response time ≤50ms; radial rigid constraint displacement hysteresis ≤0.02mm; stiffness attenuation rate after 10^6 cycles of loading ≤3%.

[0015] The present application also proposes an embodiment, an assembly method for an elastically constrained flexible joint structure, which is used for an elastically constrained flexible joint structure, and includes the following steps: using a liquid nitrogen freezing assembly process to press the locating pin into the joint base with an interference fit; using a laser interferometer to calibrate the symmetry of four sets of steel ball constraint mechanisms, with the deviation controlled to be ≤0.005mm; and tightening the top ball screw group in three increments using a torque wrench.

[0016] Beneficial Effects

[0017] As can be seen from the above, the elastically constrained flexible joint structure and its assembly method provided by the present application include a crossbeam connection part and a joint base that cooperate with each other, and four groups of symmetrically distributed steel ball constraint mechanisms are arranged between the joint base and the crossbeam connection part to form a composite connection structure of radial rigid constraint and axial elastic compensation; the periphery of the steel ball constraint mechanism is provided with an axially arranged top ball screw elastic component, which has a built-in pre-stressed spring and is coaxially installed with the axis of the crossbeam; the center of the joint base is provided with a positioning pin clearance matching structure, including a positioning pin and a pin hole with a diameter difference of 1-2mm, and the gap between the two is offset compensated by the steel ball constraint mechanism. Through this design, a composite connection of radial rigid constraint and axial elastic compensation is achieved, which effectively solves the shortcomings of traditional structures in dynamic load and small displacement compensation, and has the advantages of improving structural stability, enhancing overload resistance, achieving precise fine-tuning and dynamic balance, extending service life, and improving wear resistance and dynamic response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of an elastically constrained flexible joint structure provided in the first embodiment of the present invention;

[0020] Figure 2 A working step diagram of an assembly method of an elastically constrained flexible joint structure provided in accordance with the second embodiment of the present invention. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0023] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0024] In the current field of mechanical connection and structural stability technology, traditional connection methods and structural designs have many limitations. For example, in terms of power transmission and structural fixation, many designs are difficult to effectively constrain the offset position during operation. Once an overshoot occurs, the structure is easily damaged, the overload resistance is poor, and the system stability and durability are insufficient. Moreover, traditional structures have extremely high requirements for processing accuracy, which increases production costs and processing difficulties. When dealing with the problem of asynchrony on both sides of the beam, it is difficult to achieve flexible connection to offset the length change, and the accuracy is easily affected by the gap change during high-speed movement. Therefore, a new structural design is urgently needed to solve the above problems and improve the performance and reliability of the mechanical structure.

[0025] Example 1

[0026] refer to Figure 1, in this application, the technical problem of effectively constraining the offset position and providing axial elastic compensation during operation is solved. Specifically, the application provides an elastically constrained flexible joint structure, including a crossbeam connection part and a joint base that cooperate with each other, and four groups of symmetrically distributed steel ball constraint mechanisms are arranged between the joint base and the crossbeam connection part to form a composite connection structure of radial rigid constraint and axial elastic compensation. An axially arranged top ball screw elastic component is arranged on the periphery of the steel ball constraint mechanism, which has a built-in preload spring and is coaxially installed with the axis of the crossbeam. A positioning pin clearance matching structure is provided at the center of the joint base, including a positioning pin and a pin hole with a diameter difference of 1-2mm, and the gap between the two is offset compensated by the steel ball constraint mechanism. The elastically constrained flexible joint structure realizes radial rigid constraint and axial elastic compensation by setting four groups of symmetrically distributed steel ball constraint mechanisms, solving the problem of effectively constraining the offset position and providing axial elastic compensation during operation. The top ball screw elastic component on the periphery of the steel ball constraint mechanism provides elastic compensation through the built-in preload spring. The positioning pin clearance matching structure at the center of the joint base realizes offset compensation through the steel ball constraint mechanism, thereby ensuring the stability and accuracy of the structure.

[0027] The steel ball constraint mechanism, the top ball screw elastic component and the positioning pin clearance fit structure in the elastic constraint flexible joint structure are key terms. The steel ball constraint mechanism realizes radial rigid constraint through four groups of symmetrically distributed steel balls, the top ball screw elastic component provides axial elastic compensation through the built-in pre-stressed spring, and the positioning pin clearance fit structure realizes offset compensation through the steel ball constraint mechanism. The introduction and explanation of these terms help to understand the working principle of the structure and its role in solving technical problems.

[0028] The main features of the elastically constrained flexible joint structure include four sets of symmetrically distributed steel ball constraint mechanisms, a top ball screw elastic component and a locating pin clearance fit structure. The four sets of steel ball constraint mechanisms are evenly distributed between the joint base and the beam connection to form a radial rigid constraint. The top ball screw elastic component provides axial elastic compensation through a built-in preload spring and is coaxial with the beam axis when installed. The locating pin clearance fit structure includes a locating pin and a pin hole with a diameter difference of 1-2mm, and the gap between the two is offset compensated by a steel ball constraint mechanism. Specifically, the steel ball constraint mechanism can fine-tune the gap through a differential set screw with an adjustment accuracy of up to 0.01mm. The preload spring in the top ball screw elastic component has a certain stiffness coefficient to ensure the effect of elastic compensation. The spherical contact portion at the end of the locating pin matches the diameter of the steel ball, further improving the stability of the structure.

[0029] Compared with the prior art, the elastically constrained flexible joint structure of the present application has significant advantages in many aspects. The traditional mechanical connection method is difficult to effectively constrain the offset position during operation, and has poor overload resistance, insufficient system stability and durability. However, the present application realizes a composite connection structure of radial rigid constraint and axial elastic compensation by setting four groups of symmetrically distributed steel ball constraint mechanisms, which significantly improves the stability and durability of the system. In addition, the design of the top ball screw elastic component and the locating pin clearance fit structure further reduces the requirements for processing accuracy, reducing production costs and processing difficulty.

[0030] The elastically constrained flexible joint structure realizes radial rigid constraint and axial elastic compensation by setting four groups of symmetrically distributed steel ball constraint mechanisms, solving the problem of effectively constraining the offset position and providing axial elastic compensation during operation. The top ball screw elastic component on the periphery of the steel ball constraint mechanism provides elastic compensation through the built-in pre-stressed spring. The locating pin clearance fit structure at the center of the joint base realizes offset compensation through the steel ball constraint mechanism, thereby ensuring the stability and accuracy of the structure. Specifically, the steel ball constraint mechanism realizes gap fine-tuning through differential set screws, and the pre-stressed spring in the top ball screw elastic component has a certain stiffness coefficient to ensure the effect of elastic compensation. The spherical contact portion at the end of the locating pin matches the diameter of the steel ball, further improving the stability of the structure. Therefore, the present application not only improves the performance and reliability of the mechanical structure, but also reduces the production cost and processing difficulty.

[0031] Furthermore, the present application also proposes that the ball screw elastic assembly includes a plunger sleeve, a compensation spring and a preload adjustment screw, and the stiffness coefficient K of the compensation spring satisfies: 10N / mm≤K≤30N / mm, and the spring pre-compression amount can be adjusted in the range of 2-5mm, and the maximum stroke compensation amount is ≥3mm.

[0032] The ball screw elastic component is composed of a plunger sleeve, a compensation spring and a preload adjustment screw. The stiffness coefficient of the compensation spring ranges from 10N / mm to 30N / mm, the pre-compression amount can be adjusted between 2-5mm, and the maximum stroke compensation amount is not less than 3mm. Through these technical features, the ball screw elastic component can be effectively compensated and adjusted in the elastically constrained flexible joint structure, improving the stability and durability of the structure.

[0033] The stiffness coefficient K of the compensation spring is selected in the range of 10N / mm to 30N / mm in order to provide appropriate elastic compensation capacity under different working conditions. The preload adjustment screw can adjust the pre-compression of the spring to vary it within the range of 2-5mm to adapt to different preload requirements. The maximum stroke compensation is not less than 3mm, which means that during operation, the component can provide at least 3mm of displacement compensation to cope with possible mechanical deformation or position offset.

[0034] By adopting the above-mentioned technical means, the present application can realize effective compensation and adjustment of the elastic component of the ball screw in the elastically constrained flexible joint structure. Specifically, the adjustment of the stiffness coefficient and pre-compression amount of the compensation spring enables the component to provide a stable elastic compensation effect under different working conditions, thereby improving the stability and durability of the entire structure. Compared with the prior art, the technical solution of the present application can not only effectively solve the problem of offset compensation in mechanical connections, but also adapt to different working environments and load conditions by adjusting the preload force and compensation amount, significantly improving the performance and reliability of the mechanical structure.

[0035] Furthermore, the present application also proposes that four groups of steel ball constraint mechanisms are arranged at four quadrant points of the joint base in orthogonal directions, each group contains two precision steel balls with a diameter tolerance of ≤0.005mm, and the gap is fine-tuned by differential set screws with an adjustment accuracy of 0.01mm.

[0036] Four sets of steel ball restraint mechanisms are arranged at four quadrants of the joint base in orthogonal directions. This arrangement ensures the symmetry and stability of the structure. Each set contains two precision steel balls with a diameter tolerance of ≤0.005mm. These precision steel balls ensure high precision and low wear of the structure through high-precision manufacturing processes. The gap is fine-tuned by differential set screws with an adjustment accuracy of 0.01mm. This high-precision adjustment method can effectively control the gap of the steel balls and ensure the stability and accuracy of the structure during operation.

[0037] Four groups of steel ball constraint mechanisms are arranged in four quadrants of the joint base in orthogonal directions, and each group contains two precision steel balls. The diameter tolerance of the steel balls is controlled at ≤0.005mm, and the gap is fine-tuned by differential set screws. The differential set screws have a double thread structure, and fine-tuning is achieved through the relative movement of the inner and outer threads, with an adjustment accuracy of up to 0.01mm. Specific implementation methods include but are not limited to the following: First, use high-precision CNC machine tools to process steel balls and set screws to ensure their dimensional accuracy; second, use high-precision measuring equipment to detect and calibrate steel balls and set screws to ensure that they meet design requirements; third, through reasonable assembly technology, ensure the accuracy and consistency of steel balls and set screws during assembly.

[0038] The present application ensures the symmetry and stability of the structure by arranging four groups of steel ball restraint mechanisms at the four quadrant points of the joint base. Each group of steel ball restraint mechanisms contains two precision steel balls, and the diameter tolerance is controlled at ≤0.005mm. The high precision and low wear of the structure are guaranteed by the high-precision manufacturing process. The gap is fine-tuned by differential set screws with an adjustment accuracy of 0.01mm, which effectively controls the gap of the steel balls and ensures the stability and precision of the structure during operation. Compared with the prior art, the present application has significant improvements in structural layout, manufacturing accuracy and adjustment methods, improves the stability and precision of the structure, and solves the problems of the layout of the steel ball restraint mechanism on the joint base and the fine-tuning of the gap.

[0039] The differential set screw has a double thread structure, including an external thread part and an internal push cone surface. The thread lead difference is designed to be 0.5mm / turn, which realizes the nano-level displacement adjustment of the steel ball. The double thread structure of the differential set screw is used in conjunction with the external thread part and the internal push cone surface. The thread lead difference is designed to be 0.5mm / turn, which realizes the nano-level displacement adjustment of the steel ball. Through this structural design, precise adjustment can be made within a very small displacement range, solving the problem of how to achieve nano-level displacement adjustment of the steel ball.

[0040] The double thread structure of the differential set screw is a precise mechanical design. The external thread part and the internal push cone surface cooperate with each other, and the adjustment of micro displacement is achieved through the design of the thread lead difference. Specifically, the external thread part drives the internal push cone surface to move by rotation. Since the thread lead difference is only 0.5mm / turn, very fine displacement adjustment can be achieved, thus achieving nanometer-level accuracy. In addition, this structural design can further optimize the adjustment accuracy by changing the size of the thread lead difference to adapt to different application requirements.

[0041] This design has significant advantages over the existing technology. By adopting a double-thread structure and a thread lead difference design, nanometer-level displacement adjustment of the steel ball is achieved, solving the problem that traditional structures are difficult to achieve high-precision adjustment. As a result, a more stable and precise connection method can be provided in the field of mechanical connection and structural stability technology, improving the stability and reliability of the system.

[0042] The fit between the locating pin and the pin hole satisfies: 0.8mm≤Dhole-Dpin≤1.5mm, and a spherical contact portion is provided at the end of the locating pin, and its curvature radius R and the steel ball diameter d satisfy: R=1.2d±0.1mm.

[0043] The clearance between the locating pin and the pin hole is between 0.8mm and 1.5mm. This design can ensure the stability of the locating pin in the pin hole while allowing a certain degree of offset compensation. A spherical contact portion is provided at the end of the locating pin, and the relationship between its radius of curvature and the diameter of the steel ball is R=1.2d±0.1mm. This design helps to provide stable contact and support in the radial and axial directions, further enhancing the stability and accuracy of the structure. The above technical means can effectively solve the problem of the clearance between the locating pin and the pin hole, ensuring that the locating pin can be stably maintained in the pin hole during operation, while allowing a certain degree of offset compensation, thereby improving the stability and accuracy of the mechanical structure.

[0044] Specifically, the end of the positioning pin is designed as a spherical contact part, which not only provides a larger contact area, but also can adapt to the slight deformation or position error of the pin hole to a certain extent. The relationship between the radius of curvature R of the spherical contact part and the diameter d of the steel ball is designed to be R = 1.2d ± 0.1mm, which can ensure that the spherical contact part and the inner wall of the pin hole can effectively contact, thereby providing stable support and positioning. In addition, this design method can also disperse the force, reduce the risk of excessive force at a single point, and improve the durability of the structure.

[0045] As a preferred embodiment, the locating pin can be made of high-strength material, such as hardened steel or cemented carbide, to improve its wear resistance and service life. In order to further improve the matching accuracy, precision machining and testing methods can be used during the manufacturing process to ensure that the dimensional tolerance of the locating pin and the pin hole is within the design range. In addition, in actual applications, the surface of the locating pin can be properly lubricated according to specific needs to reduce friction and wear.

[0046] Therefore, the present application not only solves the problem of the clearance between the locating pin and the pin hole by optimizing the clearance between the locating pin and the pin hole and designing the spherical contact portion at the end of the locating pin, but also improves the stability and precision of the mechanical structure. Compared with the prior art, the technical solution of the present application allows a certain offset compensation while ensuring the stability of the locating pin, has stronger adaptability and a more reliable structure.

[0047] Furthermore, the constrained contact surface of the joint matrix adopts a gradient heat treatment process, the surface hardness is HRC62±2, the core hardness is maintained at HRC35-40, and the depth of the hardened layer is 0.3-0.5mm.

[0048] Through the gradient heat treatment process, the surface hardness of the joint matrix is ​​significantly improved to HRC62±2, thereby enhancing the surface wear resistance and fatigue resistance. At the same time, the core hardness is maintained at HRC35-40, so that the joint matrix has a certain toughness while maintaining high hardness, avoiding brittle fracture caused by excessive hardness. The depth of the hardened layer is controlled at 0.3-0.5mm, ensuring a reasonable transition between the surface hardness and the core toughness. These technical features effectively solve the problem of how to improve the surface hardness and wear resistance of the joint matrix while maintaining the toughness of the core through mutual cooperation.

[0049] The gradient heat treatment process can be achieved in the following ways: One way is to use a multi-stage heating and cooling process in different temperature ranges to achieve different hardnesses of the surface and the core. Another way is to use surface carburizing or nitriding treatment, and then adjust the core hardness through a temperature-controlled tempering process. As a preferred embodiment, a laser quenching process can be used to quickly heat and cool the surface to form a high-hardness surface layer, and the depth of the hardened layer and the core hardness can be adjusted by controlling the laser power and scanning speed.

[0050] This application adopts a gradient heat treatment process to make the surface hardness of the joint matrix reach HRC62±2, significantly improving the surface wear resistance and fatigue resistance, while the core hardness is maintained at HRC35-40, ensuring the toughness of the joint matrix and avoiding the risk of brittle fracture. Compared with the prior art, this application provides an effective solution to achieve a balance between high hardness and toughness of the joint matrix, thereby improving the performance and reliability of the overall structure.

[0051] refer to Figure 2 Furthermore, the present application also proposes that it also includes a dynamic balance monitoring module, which is provided with a strain sensor embedded in the joint base, detecting the offset ε and satisfying: |ε|≤0.15mm; a pressure sensor provided in the ball screw assembly, monitoring the spring force fluctuation ΔF and satisfying: |ΔF / F0|≤5% where F0 is the initial preload.

[0052] The dynamic balance monitoring module includes a strain sensor and a pressure sensor. The strain sensor is embedded in the joint base to detect the offset of the joint structure during operation and ensure that the offset does not exceed 0.15mm. The pressure sensor is installed on the top ball screw assembly to monitor the fluctuation of the spring force and ensure that the spring force fluctuation does not exceed 5% of the initial preload. These two sensors ensure that the joint structure remains stable during operation through real-time monitoring and feedback, avoiding structural damage or performance degradation caused by excessive offset and spring force fluctuations.

[0053] The strain sensor can use a high-precision resistance strain gauge or a fiber Bragg grating sensor to ensure detection accuracy and reliability. The pressure sensor can use a piezoelectric or capacitive sensor to accurately monitor the change of spring force. The sensor signal can be transmitted to the control unit in real time through the data acquisition system, and the control unit performs data processing and feedback control. Furthermore, the dynamic balance monitoring module can also integrate a temperature compensation function to eliminate the influence of ambient temperature changes on the sensor measurement accuracy.

[0054] Through the dynamic balance monitoring module, the joint structure of the present application can monitor and adjust the offset and spring force in real time during operation to ensure the stability and reliability of the joint structure. Compared with the prior art, the joint structure of the present application can effectively avoid structural damage or performance degradation caused by excessive fluctuations in the offset and spring force, thereby improving the service life and working performance of the joint structure.

[0055] Furthermore, the present application also proposes that the mounting surface of the beam connection portion is provided with a laser cladding wear-resistant coating, the coating composition is WC-12Co, the thickness is 0.2-0.3mm, and the surface roughness Ra≤0.4μm.

[0056] By setting a laser cladding wear-resistant coating on the mounting surface of the beam connection, the wear resistance and service life of the connection part are significantly improved. The coating composition is WC-12Co, which has high hardness and wear resistance. The thickness range is 0.2-0.3mm, which ensures the effectiveness and uniformity of the coating. The surface roughness Ra≤0.4μm ensures the smoothness of the connection surface, thereby reducing friction and wear, and further improving the stability and reliability of the connection part.

[0057] The component of laser cladding wear-resistant coating, WC-12Co, is a common cemented carbide with excellent wear resistance and corrosion resistance. The thickness is controlled between 0.2-0.3mm, which can ensure the effectiveness of the coating while avoiding material waste and weight increase caused by excessive thickness. The surface roughness Ra≤0.4μm is achieved through precision machining and control of process parameters, ensuring the smoothness and matching accuracy of the connection parts and effectively reducing the friction coefficient.

[0058] The present application solves the problem of insufficient wear resistance and stability of mechanical connection parts by providing a laser cladding wear-resistant coating on the mounting surface of the crossbeam connection part. Compared with the traditional connection method, it has significant wear resistance and corrosion resistance and prolongs the service life. At the same time, the uniformity and surface smoothness of the coating improve the stability of the connection part and reduce the risk of failure caused by friction and wear. Therefore, the present application is of great significance in improving the performance and reliability of mechanical structures.

[0059] Furthermore, the present application also proposes that the structure meets the dynamic response indicators: axial elastic compensation response time ≤50ms; radial rigid constraint displacement hysteresis ≤0.02mm; stiffness attenuation rate after 10^6 cycles of loading ≤3%.

[0060] Through the mutual cooperation of the above technical features, it is possible to effectively solve the problem of achieving efficient axial elastic compensation and radial rigidity constraint in the field of mechanical connection and structural stability technology, while ensuring the stability and durability of the system under high-frequency cyclic loads. The setting of dynamic response indicators ensures the accuracy and stability of the system in high-speed motion, while improving the durability of the structure and reducing maintenance costs.

[0061] The implementation of this technical solution includes the following aspects. First, the axial elastic compensation response time is ≤50ms, which ensures a fast response in high-speed movement and reduces overshoot and offset during movement. Secondly, the radial rigid constraint displacement hysteresis is ≤0.02mm, which ensures the high rigidity constraint of the structure in the radial direction and reduces the accuracy problems caused by gap changes. Finally, the stiffness attenuation rate after 10^6 cycles of loading is ≤3%, indicating that the structure has good durability and stability under high-frequency cyclic loading.

[0062] Specifically, the realization of axial elastic compensation response time can be achieved by optimizing the design and material selection of elastic components, such as using materials with high elastic modulus and optimizing the pre-compression of springs. The control of radial rigid constraint displacement hysteresis can be achieved by precise adjustment of precision steel balls and differential set screws. For the stiffness attenuation rate after cyclic loading, its durability can be enhanced by improving the heat treatment process and material selection of the joint matrix.

[0063] Therefore, this application effectively solves the problem of insufficient stability and durability of traditional mechanical connection methods under high-frequency cyclic loads through optimized structural design and material selection. Compared with the prior art, this application significantly improves the accuracy and stability of the system in high-speed motion, reduces maintenance costs, and has significant technical advantages while achieving efficient axial elastic compensation and radial rigidity constraints.

[0064] Example 2

[0065] refer to Figure 2 The present invention also includes another embodiment, an assembly method for an elastically constrained flexible joint structure, comprising the following steps: (S1) using a liquid nitrogen freezing assembly process to press the locating pin into the joint base with an interference fit; (S2) using a laser interferometer to calibrate the symmetry of four sets of steel ball constraint mechanisms, with the deviation controlled to be ≤0.005mm; (S3) using a torque wrench to tighten the top ball screw set in three increments.

[0066] Step (S1) adopts liquid nitrogen freezing assembly technology, and shrinks the locating pin through low temperature, so as to achieve interference fit and press it into the joint matrix. This process ensures the close fit between the locating pin and the joint matrix, and improves the stability and accuracy of the assembly. Step (S2) uses a laser interferometer to calibrate the symmetry of the four sets of steel ball constraint mechanisms, and controls the deviation within 0.005mm through high-precision measurement means to ensure the symmetry of the steel ball constraint mechanism, thereby improving the symmetry and stability of the joint structure. Step (S3) uses a torque wrench to tighten the top ball screw group in three increments, gradually increasing the tightening force of the screw to avoid stress concentration and structural deformation caused by one-time tightening, ensuring that the tightening force of the screw group is evenly distributed, and improving the reliability and accuracy of the assembly. Through the mutual cooperation of the above steps, the present application effectively solves the technical problems of accuracy and stability of the elastically constrained flexible joint structure during the assembly process.

[0067] The specific implementation method of the liquid nitrogen freezing assembly process includes immersing the locating pin in liquid nitrogen to rapidly reduce its temperature, thereby shrinking the size of the locating pin. The shrunk locating pin is then quickly inserted into the hole of the joint base. As the temperature rises, the locating pin returns to its original size to achieve an interference fit. The calibration process of the laser interferometer can be performed by setting measurement points at symmetrical positions of four sets of steel ball constraint mechanisms and using the principle of laser interference for high-precision measurement and adjustment. The incremental tightening process of the torque wrench can be divided into three stages, gradually increasing the torque value to ensure that the screw group is evenly stressed after each tightening to avoid stress concentration.

[0068] The present application improves the assembly accuracy and stability of the elastically constrained flexible joint structure by adopting technical means such as liquid nitrogen freezing assembly process, laser interferometer calibration and torque wrench incremental tightening. Compared with the prior art, the present application effectively controls the matching accuracy of the locating pin and the joint base during the assembly process, ensures the symmetry of the steel ball constraint mechanism, and avoids stress concentration and structural deformation by incrementally tightening the screw group in batches, thereby improving the reliability and accuracy of the assembly. Therefore, the present application has significant advantages in solving the problems of assembly accuracy and stability of elastically constrained flexible joint structures.

[0069] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An elastically constrained flexible joint structure, comprising a cross beam connection portion and a joint base (3) that cooperate with each other, characterized in that: Four groups of symmetrically distributed steel ball restraint mechanisms (6) are arranged between the joint base (3) and the crossbeam connection portion, forming a composite connection structure with radial rigid restraint and axial elastic compensation; The outer periphery of the steel ball restraining mechanism (6) is provided with an axially arranged top ball screw elastic component (7), which has a built-in pre-stressed spring and is coaxially installed with the axis of the crossbeam; The center of the joint base (3) is provided with a positioning pin clearance matching structure, which includes a positioning pin (8) and a pin hole (4) with a diameter difference of 1-2 mm, and the gap between the two is offset compensated by the steel ball restraint mechanism (6).

2. The elastically constrained flexible joint structure according to claim 1, characterized in that: The ball screw elastic component (7) comprises a plunger sleeve, a compensation spring and a preload adjustment screw, wherein the stiffness coefficient K of the compensation spring satisfies: 10N / mm≤K≤30N / mm; the adjustable range of spring pre-compression is 2-5mm, and the maximum stroke compensation is ≥3mm.

3. The elastically constrained flexible joint structure according to claim 1, characterized in that: The four groups of steel ball restraint mechanisms (6) are arranged at four quadrants of the joint base (3) in orthogonal directions, and each group contains two precision steel balls with a diameter tolerance of ≤0.005 mm. The gap is finely adjusted through differential set screws (5), and the adjustment accuracy reaches 0.01 mm.

4. The elastically constrained flexible joint structure according to claim 3, characterized in that: The differential set screw (5) has a double thread structure, including an external thread portion and an internal push cone surface, and the thread lead difference is designed to be 0.5 mm / turn, which is used to achieve nanometer-level displacement adjustment of the steel ball restraint mechanism (6).

5. The elastically constrained flexible joint structure according to claim 1, characterized in that: The cooperation between the positioning pin (8) and the pin hole (4) satisfies: 0.8mm≤D hole-D pin≤1.5mm0.8mm≤D hole-D pin≤1.5mm The end of the positioning pin (8) is provided with a spherical contact portion, the curvature radius R of which satisfies the diameter d of the steel ball: R=1.2d±0.1mmR=1.2d±0.1mm.

6. The elastically constrained flexible joint structure according to claim 1, characterized in that: The constrained contact surface of the joint base (3) adopts a gradient heat treatment process, the surface hardness is HRC62±2, the core hardness is maintained at HRC35-40, and the depth of the hardened layer is 0.3-0.5mm.

7. The elastically constrained flexible joint structure according to claim 1, characterized in that: It also includes a dynamic balance monitoring module, which features: The strain sensor embedded in the joint base (3) detects the offset ε and satisfies: |ε|≤0.15mm|ε|≤0.15mm; the pressure sensor provided in the ball screw elastic component (7) monitors the spring force fluctuation ΔF and satisfies: |ΔF / F0|≤5% |ΔF / F0|≤5% Where F0 is the initial preload force.

8. The elastically constrained flexible joint structure according to claim 1, characterized in that: The mounting surface of the beam connection portion is provided with a laser cladding wear-resistant coating, the coating composition is WC-12Co, the thickness is 0.2-0.3mm, and the surface roughness Ra≤0.4μm.

9. The elastically constrained flexible joint structure according to any one of claims 1 to 8, characterized in that: The elastically constrained flexible joint structure meets the dynamic response index: The axial elastic compensation response time is ≤50ms; the radial rigid constraint displacement hysteresis is ≤0.02mm; the stiffness attenuation rate after 10^6 cycles of loading is ≤3%.

10. An assembly method of an elastically constrained flexible joint structure, used for the elastically constrained flexible joint structure according to any one of claims 1 to 9, characterized in that: The following steps are involved: Using a liquid nitrogen freezing assembly process, the positioning pin (8) is pressed into the joint base (3) with an interference fit; The symmetry of the four sets of steel ball restraint mechanisms (6) is calibrated using a laser interferometer, and the deviation is controlled to be ≤0.005 mm; Use a torque wrench to tighten the ball screw assembly in three increments.

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