Spring assembly method and spring assembly system

Abstract

This application discloses a spring assembly method and a spring assembly system, relating to the field of precision spring technology. The spring assembly method includes: controlling a first spring to rotate forward along the winding direction, thereby reducing the diameter of the first spring to a target diameter range; controlling the first spring, with its diameter reduced to the target size, to move into the inner cavity of a second spring, wherein the maximum value of the target diameter range is less than the diameter of the second spring; and controlling the first spring to rotate in the reverse direction along the winding direction, thereby increasing the diameter of the first spring and assembling it in a nested configuration with the second spring. The spring assembly method provided in this application aims to reduce the stress experienced by the spring during nested assembly.

Description

Technical Field

[0001] This application relates to the field of precision spring technology, and in particular to a spring assembly method and a spring assembly system. Background Technology

[0002] In the field of precision instrument manufacturing, such as medical equipment, springs are key elastic components, and their assembly accuracy directly affects the performance and service life of the equipment. Traditional spring assembly processes typically employ direct press-fit assembly, which has significant technical defects: when inner and outer springs are nested together, the rough axial pressing method can cause abnormal friction between the spring coils, resulting not only in stress concentration at the contact surface but also potentially causing the coating on the spring surface to peel off or the material to undergo plastic deformation. Summary of the Invention

[0003] The main objective of this application is to provide a spring assembly method and system that aims to reduce the stress experienced by springs during nested assembly.

[0004] To achieve the above objectives, the spring assembly method proposed in this application includes:

[0005] Control the first spring to rotate in the forward direction along the winding direction so that the diameter of the first spring is reduced to the target diameter range;

[0006] The first spring, whose diameter is reduced to the target size, moves into the inner cavity of the second spring, wherein the maximum value of the target diameter range is less than the diameter of the second spring;

[0007] The first spring is controlled to rotate in the opposite direction of the winding so that its diameter is increased and it is nested and matched with the second spring for assembly.

[0008] In one embodiment, the movement of the first spring, whose diameter is reduced to the target size, into the inner cavity of the second spring further includes:

[0009] When the first spring moves into the inner cavity of the second spring, the resistance to the movement of the first spring is obtained;

[0010] When the resistance of the first spring exceeds the preset resistance, the first spring is controlled to vibrate axially within the preset frequency range and the preset amplitude range.

[0011] In one embodiment, the movement of the first spring, whose diameter is reduced to the target size, into the inner cavity of the second spring further includes:

[0012] Obtain the depth of the first spring moving into the inner cavity of the second spring and a preset depth-vibration parameter mapping table, wherein the vibration parameters include amplitude and frequency;

[0013] Based on the depth of the first spring moving into the inner cavity of the second spring and a preset depth-vibration parameter mapping table, the first spring is controlled to vibrate axially with the corresponding amplitude and frequency; wherein, the depth of the first spring moving into the inner cavity of the second spring is negatively correlated with the frequency and amplitude.

[0014] In one embodiment, after the first spring, whose diameter is reduced to the target size, moves into the inner cavity of the second spring, and before the first spring, whose diameter is controlled to rotate in the opposite direction along the winding direction, the method further includes:

[0015] A preset radial force is applied to the first spring toward the inner cavity of the first spring, and the gap fluctuation value between the first spring and the second spring is obtained;

[0016] After a preset time, and if the gap fluctuation value is less than the preset fluctuation value, it is determined that the first spring, which controls the diameter to shrink to the target size, moves to the inner cavity of the second spring.

[0017] In one embodiment, controlling the first spring to rotate forward along the winding direction, so that the diameter of the first spring is reduced to a target diameter range and then the rotation stops, includes:

[0018] A first torque is applied in the positive direction along the winding direction of the first spring to reduce the diameter of the first spring to the target diameter;

[0019] When the diameter of the first spring is reduced to the target diameter, the process switches to applying a second torque to the first spring so that the diameter of the first spring remains within the target diameter range.

[0020] In one embodiment, the movement of the first spring, whose diameter is reduced to the target size, into the cavity of the second spring includes:

[0021] Adjust the relative positions of the first spring and the second spring so that the axes of the first spring and the second spring are coaxial;

[0022] The first spring is controlled to move axially so that it moves into the inner cavity of the second spring.

[0023] In one embodiment, the first spring has a plurality of first coil groups spaced apart along the length direction, and the second spring has a plurality of second coil groups spaced apart along the length direction, wherein each of the first coil group and the second coil group includes at least one spring coil.

[0024] The movement of the first spring, whose diameter is reduced to the target size, into the inner cavity of the second spring includes:

[0025] The first spring, whose diameter is reduced to the target size, moves axially.

[0026] When multiple first coil groups and multiple second coil groups are staggered in radial projection, the nesting and matching of the first spring and the second spring are determined, and the first spring is controlled to stop moving.

[0027] In one embodiment, controlling the first spring to rotate in the opposite direction along the winding direction to increase the diameter of the first spring and to nest and assemble it with the second spring includes:

[0028] A second torque is applied in the opposite direction to the winding direction of the first spring;

[0029] After the diameter of the first spring is enlarged and it is nested and matched with the second spring, the application of the second torque is stopped.

[0030] In one embodiment, stopping the application of the second torque after the diameter of the first spring is enlarged and nested and matched with the second spring includes:

[0031] After the diameter of the first spring is enlarged and it is nested and matched with the second spring, the stress between the first spring and the second spring is obtained.

[0032] When the stress between the first spring and the second spring exceeds the preset stress, the application of the second torque is stopped.

[0033] This application also provides a spring assembly system, the spring assembly system including a control device configured to implement the spring assembly method as described above.

[0034] As can be seen from the above, the spring assembly method and system provided in this application achieve nested matching assembly by controlling the forward rotation of the first spring to reduce its diameter and enter the inner cavity of the second spring, and then rotating it in the opposite direction to expand its diameter. Combined with axial vibration control, gap detection and stress feedback mechanism, it effectively avoids the friction damage and stress concentration problems caused by traditional press-fit assembly, and has the advantages of improving assembly accuracy, extending the service life of the spring and ensuring dynamic working stability. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0036] Figure 1 A flowchart of the first embodiment of the spring assembly method provided in this application;

[0037] Figure 2A flowchart of the second embodiment of the spring assembly method provided in this application;

[0038] Figure 3 A flowchart of the third embodiment of the spring assembly method provided in this application;

[0039] Figure 4 A flowchart of the fourth embodiment of the spring assembly method provided in this application;

[0040] Figure 5 A flowchart of the fifth embodiment of the spring assembly method provided in this application;

[0041] Figure 6 A flowchart of the sixth embodiment of the spring assembly method provided in this application;

[0042] Figure 7 A flowchart of the seventh embodiment of the spring assembly method provided in this application;

[0043] Figure 8 A flowchart of the eighth embodiment of the spring assembly method provided in this application;

[0044] Figure 9 A flowchart of the ninth embodiment of the spring assembly method provided in this application.

[0045] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0046] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0047] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0048] In existing traditional spring assembly processes, the direct insertion method leads to localized stress concentration at the contact surface. This stress concentration phenomenon originates from the instantaneous overload at the contact point between the spring coils, especially in the context of miniature spring nesting required in high-precision medical devices, where the elastic limit of the spring material is easily exceeded. The uneven distribution of stress directly affects the fatigue life of the spring assembly, while axial deviations during assembly can induce additional frictional resistance, resulting in microscopic scratches on the spring surface and compromising the dimensional tolerances and surface integrity of the precision spring.

[0049] For example, in the assembly of a double-spring nested mechanism for a medical catheter, the inner spring is forcibly pressed in using a linear advancement method. Due to the mismatch in the helix angles of the two springs, instantaneous stress and shear force exceeding the material's yield strength are generated at the contact point. Exemplarily, during assembly, the third and fifth turns of the inner spring interfere with the second and fourth turns of the outer spring, respectively, forming two stress peak regions. When the angular deviation during axial advancement exceeds 0.5 degrees, lateral shear force is generated at the spring ends, causing plastic deformation of the helical structure.

[0050] Understandably, springs used in medical settings are precision springs. Stress concentration areas in the spring can trigger dislocation multiplication in the spring material, leading to premature fatigue fracture under cyclic loads. Microstructural defects generated during assembly can reduce the adhesion strength of the spring's conductive coating, accelerating material corrosion during sterilization of medical devices. Non-uniform contact pressure between springs can also distort the magnetic field distribution of the electromagnetic drive mechanism, affecting the positioning accuracy of medical catheters within blood vessels. More seriously, residual stress-induced dimensional rebound can cause millimeter-level displacement of nested components at body temperature, directly impacting the safety boundaries of interventional procedures.

[0051] Faced with the aforementioned problems, this application first analyzes the root causes of stress concentration in traditional assembly processes, finding that the geometric interference and elastic deformation characteristics of the spring helical structure are not being properly utilized. Specifically, the direct-drive assembly method fails to consider the correlation between the spring winding direction and diameter changes, leading to uncontrollable stress distribution at the contact points. To address this, considering the physical relationship between the spring's rotational characteristics and diameter changes, it is found that rotation along the winding direction produces controllable diameter contraction, while reverse rotation restores the original dimensions. This dynamic adjustment method ensures assembly clearance while avoiding permanent deformation.

[0052] To address this, this application proposes a spring assembly method for assembling at least two springs, aiming to reduce the stress on the corresponding springs during assembly. In one embodiment, as... Figure 1 As shown, the spring assembly method includes steps S100 to S300.

[0053] In this embodiment, step S100 involves controlling the first spring to rotate forward along the winding direction so that the diameter of the first spring is reduced to the target diameter range.

[0054] In this embodiment, step S200 involves controlling the first spring, whose diameter is reduced to the target size, to move into the inner cavity of the second spring.

[0055] The maximum value of the target diameter range is less than the diameter of the second spring.

[0056] In this embodiment, step S300 involves controlling the first spring to rotate in the opposite direction along the winding direction, so that the diameter of the first spring is enlarged and it is nested and matched with the second spring for assembly.

[0057] Among them, rotating in the forward direction along the winding direction refers to applying rotational force along the spiral direction of the spring's own spiral structure. Specifically, this can be achieved by using a servo motor to drive the spring end clamp. This operation utilizes the elastic deformation characteristics of the spring material to compress the coil spacing through torque, thereby achieving diameter shrinkage.

[0058] The target diameter range refers to a pre-defined range of spring outer diameters. This range can be monitored in real-time using a laser rangefinder to track changes in the spring diameter. The upper limit of this range must ensure that the scaled-down first spring can enter the inner cavity of the second spring without contact, avoiding assembly interference. It's important to note that the diameter of the first spring refers to its outer diameter, i.e., the diameter of the outermost contour including the thickness of the spring wire itself, not the inner diameter of its cavity. Similarly, the target diameter range is also defined based on the outer diameter of the first spring, ensuring that the maximum value of the scaled-down outer diameter is still less than the inner diameter (i.e., the cavity diameter) of the second spring, thus creating sufficient interference-free clearance during assembly. This avoids any radial contact or friction when the first spring is inserted into the inner cavity of the second spring, effectively preventing surface scratches, localized stress concentration, and plastic deformation of the helical structure, ensuring the smoothness of the assembly process and the final geometric accuracy and functional reliability of the component.

[0059] The process involves controlling the first spring, whose diameter has been reduced to the target size, to move into the inner cavity of the second spring. This can be achieved by a high-precision linear propulsion mechanism that smoothly inserts the first spring into the inner hole of the second spring along the axial direction. During this movement, the first spring maintains a contracted diameter, ensuring a contactless or clearance-fitting insertion relationship with the inner wall of the second spring, thus avoiding mechanical interference, scratching, or localized stress concentration during assembly. Optionally, the linear propulsion mechanism includes a ball screw module driven by a servo motor or a linear actuator driven by a voice coil motor, possessing micron-level positioning accuracy and controllable speed to ensure the smoothness and repeatability of the insertion process. Furthermore, to prevent axial misalignment during assembly, the central axes of the first and second springs can be calibrated before insertion using a visual calibration system or a coaxiality detection device to ensure minimal coaxiality error. Simultaneously, a force sensor can be used to monitor the insertion force in real time. When abnormal resistance is detected, a safety shutdown mechanism is triggered to prevent plastic deformation of the spring or equipment damage due to accidental jamming.

[0060] The reverse rotation along the winding direction refers to applying a rotational force in the opposite direction to the spring winding direction. This can be achieved by using a servo motor to drive the spring end clamp. This operation utilizes the elastic deformation characteristics of the spring material to restore the coil to its initial state through torque. Specifically, a torque sensor can be used to control the rotation angle, releasing the elastic potential energy stored in the spring to restore the diameter to its original size. The elastic deformation of the material is used to achieve a clearance fit with the second spring.

[0061] This application achieves stress-free nested assembly by controlling the deformation of the spring through staged rotation. First, forward rotation shrinks the spring diameter to establish assembly conditions. Then, axial positioning is used to avoid contact friction. Finally, reverse rotation releases elastic potential energy to restore the original size and complete the matching. The entire process is based on the deformation control of the spring itself, replacing the traditional forced insertion method and eliminating the risk of damage caused by assembly stress.

[0062] The working process and principle of this application are as follows: The spring assembly method includes three key steps: First, the first spring is controlled to rotate forward along the winding direction, reducing its diameter to the target diameter range. This step utilizes the helical structure of the spring to achieve controllable diameter shrinkage through rotation. Second, the first spring, with its diameter reduced to the target size, is moved into the inner cavity of the second spring. During this process, the maximum value of the target diameter range is set to be smaller than the diameter of the second spring, ensuring that the first spring can smoothly enter the inner cavity of the second spring without interference. Third, the first spring is controlled to rotate in the reverse direction along the winding direction, expanding its diameter and nesting it with the second spring for assembly. This step utilizes the elastic deformation characteristics of the spring material, restoring the diameter of the first spring through reverse rotation, achieving a tight nesting with the second spring. These three steps form a closed-loop control process: forward rotation to reduce diameter establishes assembly conditions, axial movement completes initial positioning, and reverse rotation to expand diameter achieves final matching. The synergistic effect of each step achieves the technical effect of reducing assembly stress. By precisely controlling the rotation direction and deformation, the stress concentration problem caused by traditional direct insertion is eliminated.

[0063] As an optional embodiment, the solution of this application is implemented as follows: First, a stepper motor is used to control the first spring to rotate forward along its winding direction. During the rotation, the diameter change of the first spring is monitored in real time using a laser diameter gauge. When the diameter of the first spring shrinks to a preset target diameter range, the stepper motor stops rotating. Further, a precision positioning platform is used to control the first spring, whose diameter has shrunk, to move axially. During the movement, a force sensor monitors the motion resistance of the first spring. When the first spring is completely inside the cavity of the second spring, the precision positioning platform stops moving. Finally, the stepper motor is restarted to control the first spring to rotate in the reverse direction along its winding direction. During the reverse rotation, strain gauges monitor the contact stress between the first spring and the second spring. When the contact stress reaches a preset value, the reverse rotation stops, completing the nested matching assembly of the springs.

[0064] Understandably, the nested matching assembly results in the outer diameter of the first spring gradually expanding during its reverse rotation recovery process, forming a stable and uniform clearance fit or transition fit with the inner wall of the second spring. This matching process is based on the elastic deformation characteristics of the material, without producing plastic damage, and the contact stress is continuously distributed circumferentially along the helix, avoiding stress concentration caused by point contact or local compression in traditional assembly. Optionally, a micrometer-level design gap is maintained between the two springs in the final nested structure.

[0065] Optionally, the first spring and the second spring can be precision springs, which can be used in medical devices, such as electromagnetic positioning modules for interventional catheter guidance systems, microsurgical instrument drive mechanisms, or implantable medical devices.

[0066] It is particularly important to note that the first spring can be a multi-strand wire spring, i.e., a composite structure spring made of multiple thin metal wires twisted together according to a specific helical pattern. Such springs possess excellent flexibility, fatigue resistance, and radial self-adaptation capability, and are commonly used in precision applications. When this method is applied to multi-strand wire springs, during the reverse rotation recovery phase, the multi-strand wire spring exhibits good structural memory and self-adaptation capability. When its outer diameter recovers and contacts the inner wall of the outer spring, the relative positions of each strand can be finely adjusted, forming a more uniform circumferential contact pressure distribution, reducing local high-stress areas, and improving the stability and smoothness of the nested structure. Furthermore, multi-strand wire springs are made of multiple thin wires twisted together, and their internal structure contains minute gaps and interlayer slip mechanisms. When a forward rotational torque is applied, the metal wires can respond more quickly to torsional deformation through relative sliding and rearrangement, thereby producing a greater radial contraction effect under the same torque. Thus, applying this method to multi-strand wire springs enables lower drive energy required for assembly, more sensitive control, and suitability for miniaturized, low-torque driven automated assembly systems.

[0067] Understandably, this method can achieve nested assembly of multiple springs. When there are three springs, the spring that has already been nested and assembled can be regarded as the first spring, and the third spring that needs to be nested again can be regarded as the second spring.

[0068] The lengths of the first spring and the second spring can be the same or different.

[0069] By employing the above-described solution, this application effectively addresses the problem of spring damage caused by excessive stress due to direct insertion during spring assembly. This reduces stress concentration during spring assembly, preventing permanent deformation or damage to the spring material.

[0070] In some of the solutions described above in this application, when the first spring enters the inner cavity of the second spring, the movement resistance may be too great due to contact surface friction or structural interference. Forcibly pushing it in may cause damage to the spring surface or permanent deformation.

[0071] In one embodiment, such as Figure 2 As shown, step S200 also includes steps S211 and S212.

[0072] In this embodiment, step S211 is to obtain the motion resistance of the first spring.

[0073] In this embodiment, step S212 involves controlling the first spring to vibrate axially within a preset frequency range and a preset amplitude range when the motion resistance exceeds a preset resistance.

[0074] In one feasible implementation, the motion resistance can be obtained by real-time acquisition of axial propulsion force data via a pressure sensor. The preset resistance can be set to 70%-90% of the critical safety value based on the yield strength of the spring material. The preset frequency range can be set to 10-50Hz, and the preset amplitude range can be set to 0.1-0.5mm. The vibration direction is strictly limited to the axial direction to avoid secondary interference caused by radial offset. When the motion resistance exceeds the preset resistance, the vibration control module initiates axial vibration, eliminating static friction on the contact surface through periodic displacement, while simultaneously using vibration energy to induce local deformation release of the spring. The vibration parameters are related to the spring stiffness coefficient; for example, for a medical spring with a wire diameter of 0.3mm, a frequency of 20Hz and an amplitude of 0.2mm are preferred. The axial vibration and the rotational diameter reduction action work together to reduce the coefficient of friction on the contact surface while maintaining the diameter reduction, thus avoiding stress concentration caused by continuous unidirectional propulsion.

[0075] Specifically, during axial propulsion, a pressure sensor continuously monitors the resistance to motion. When the resistance reaches a preset level, for example, if a sudden increase in resistance exceeding 20% ​​of the threshold curve is detected, the vibration actuator immediately intervenes, driving the first spring to vibrate axially at a frequency of 20Hz and an amplitude of 0.2mm. This vibration causes microscopic slippage on the contact surface, converting static friction into dynamic friction and reducing the coefficient of friction by approximately 30%-50%. Simultaneously, the periodic strain caused by the vibration redistributes the local stress in the spring, eliminating jamming caused by assembly path deviations. Vibration parameters are optimized through finite element simulation to ensure that the energy is sufficient to overcome the resistance but below the material fatigue limit. For example, an amplitude exceeding 0.5mm may lead to plastic deformation; therefore, closed-loop control dynamically adjusts the amplitude within a safe range. This process maintains assembly accuracy while reducing the maximum assembly resistance by more than 40%, effectively preventing scratches or permanent deformation of the spring surface.

[0076] As an optional embodiment, the solution of this application is implemented as follows: When the first spring moves into the inner cavity of the second spring, the motion resistance of the first spring is acquired in real time by a force sensor. When the detected motion resistance exceeds a preset resistance value, for example, exceeding 10N, the control system will activate the vibration mechanism. The vibration mechanism can be an electromagnetic actuator or a piezoelectric ceramic actuator, controlling the first spring to vibrate axially within a preset frequency range, the frequency of which can be adjusted between 20Hz and 200Hz. Simultaneously, the preset amplitude range of the vibration can be controlled between 0.1mm and 1mm. The vibration duration can be adjusted according to actual conditions; for example, after 5 seconds, the motion resistance is detected again. If the resistance decreases below the preset resistance value, the vibration stops and the first spring continues to advance; if the resistance is still too high, the vibration continues or the vibration parameters are adjusted.

[0077] In one embodiment, the first spring is a multi-strand wire spring. When the axial vibration-assisted insertion is applied, the internal structural characteristics of the multi-strand wire spring enable it to utilize vibration energy more efficiently and respond better. The tiny gaps between the wires and the inherent tendency to slip allow vibration energy to be transferred more effectively to the entire spring body and overcome microstatic friction, maintaining good passability even at complex contact interfaces (such as when there are minor unevennesses in the inner cavity of the second spring). This helps achieve ideal drag reduction at lower vibration energy (amplitude, frequency), reducing the negative impact of vibration on the spring itself or the assembly system.

[0078] Through the above technical solution, this application can effectively solve the problem of excessive motion resistance that may be encountered when the first spring enters the inner cavity of the second spring. By monitoring the motion resistance in real time and applying axial vibration when necessary, the static friction between the contact surfaces can be reduced, avoiding damage or permanent deformation of the spring surface. This dynamic adjustment mechanism ensures the smoothness and reliability of the spring nesting process, improving assembly efficiency and product quality.

[0079] In some of the solutions described above in this application, a technical means of assisting the first spring to enter the inner cavity of the second spring through axial vibration is proposed. However, during the assembly process, due to the change in the insertion depth of the first spring, its contact state and frictional resistance with the inner wall of the second spring will dynamically change. If fixed vibration parameters are used, the amplitude at the shallow position may be too large, causing spring deformation, while the amplitude at the deep position may be insufficient to overcome the resistance, making it impossible to achieve dynamically adapted vibration control.

[0080] In one embodiment, such as Figure 3 As shown, step S200 also includes steps S221 and S222.

[0081] In this embodiment, step S221 involves obtaining the depth of the first spring moving into the inner cavity of the second spring and a preset depth-vibration parameter mapping table.

[0082] The vibration parameters include amplitude and frequency.

[0083] In this embodiment, step S222 involves controlling the first spring to vibrate axially with the corresponding amplitude and frequency based on the depth of the first spring moving into the inner cavity of the second spring and a preset depth-vibration parameter mapping table.

[0084] Among them, the depth of the first spring moving into the inner cavity of the second spring is negatively correlated with the frequency and amplitude.

[0085] The preset depth-vibration parameter mapping table can contain multiple discrete depth nodes and corresponding vibration parameter combinations. For example, for every 5mm increase in depth, the frequency decreases by 2Hz and the amplitude decreases by 0.1mm. The gradient of vibration parameter changes can be generated by fitting experimental data. For example, the frequency can be set to 50Hz and the amplitude to 0.5mm in the depth range of 0-10mm, and adjusted to 40Hz and 0.4mm in the depth range of 10-20mm. Depth data can be collected by a laser rangefinder, and vibration parameter adjustment commands are transmitted to the piezoelectric ceramic actuator through a closed-loop control system. The negative correlation is reflected in the fact that as the depth increases, the system automatically reduces the vibration energy input to avoid excessive deformation while maintaining effective penetration.

[0086] Specifically, in one feasible embodiment, when the first spring begins to enter the inner cavity of the second spring, a laser rangefinder sensor monitors the insertion depth in real time and inputs the data into the control unit. The control unit calls a preset depth-vibration parameter mapping table; for example, when a depth of 5 mm is detected, it outputs a control signal with a frequency of 45 Hz and an amplitude of 0.45 mm. The piezoelectric ceramic actuator drives the first spring to generate axial vibration according to this signal, enabling it to quickly overcome the initial contact resistance in the shallow region. As the insertion depth increases to 15 mm, the system automatically switches to a frequency of 35 Hz and an amplitude of 0.35 mm. At this point, the reduced vibration intensity prevents plastic deformation between the spring coil and the inner wall of the second spring, while continuously overcoming the gradually increasing frictional resistance. The dynamic adjustment process of the vibration parameters matches the physical characteristics of the spring nesting; for example, when the depth reaches 20 mm, the frequency further decreases to 30 Hz and the amplitude to 0.3 mm, ensuring that propulsion force is maintained while energy loss is controlled during the deep nesting stage. Through the coordinated adjustment of amplitude and frequency, the vibration energy distribution during the assembly process and the resistance changes at different depths form a dynamic balance, thereby improving assembly efficiency while reducing the risk of structural damage.

[0087] As an optional embodiment, the solution of this application is specifically implemented as follows: The depth to which the first spring moves into the inner cavity of the second spring and a preset depth-vibration parameter mapping table are obtained. Vibration parameters include amplitude and frequency. The preset depth-vibration parameter mapping table can be a two-dimensional array, where one dimension represents the depth value and the other dimension represents the corresponding amplitude and frequency values. For example, when the depth is 0-5mm, the amplitude can be set to 0.5mm and the frequency can be set to 100Hz; when the depth is 5-10mm, the amplitude can be set to 0.4mm and the frequency can be set to 90Hz; when the depth is 10-15mm, the amplitude can be set to 0.3mm and the frequency can be set to 80Hz, and so on. Based on the depth to which the first spring moves into the inner cavity of the second spring and the preset depth-vibration parameter mapping table, the first spring is controlled to vibrate axially with the corresponding amplitude and frequency.

[0088] Through the above technical solution, this application achieves dynamic adjustment of vibration parameters during spring nesting. By establishing a mapping relationship between depth and vibration parameters, appropriate vibration parameters can be selected based on the real-time insertion depth of the first spring. Using larger amplitude and higher frequency at shallow depths helps overcome initial resistance; while using smaller amplitude and lower frequency at deeper depths avoids excessive vibration that could cause spring deformation. This allows for adaptation to changes in contact state and frictional resistance between springs at different depths, thus maintaining a moderate vibration-assisted effect throughout the nesting process. Consequently, it improves the efficiency and stability of spring nesting while reducing the risk of spring deformation or damage due to excessive vibration.

[0089] In some of the solutions described above in this application, when the first spring is placed into the inner cavity of the second spring and then rotated in the opposite direction, the uneven stress distribution during assembly may be caused by the unstable gap, which may damage the precision spring structure.

[0090] In one embodiment, such as Figure 4 As shown, steps S410 and S420 are also included between steps S100 and S200.

[0091] In this embodiment, step S410 involves applying a preset radial force toward the inner cavity of the first spring and obtaining the gap fluctuation value between the first spring and the second spring.

[0092] In this embodiment, in step S420, if the gap fluctuation value is less than the preset fluctuation value, it is determined that the first spring with the control diameter reduced to the target size will move to the inner cavity of the second spring.

[0093] It is understandable that applying a preset radial force toward the inner cavity of the first spring can simulate the actual contact state during the assembly process, actively stimulating the deformation response of the spring under stress conditions, thereby effectively exposing local geometric inconsistencies caused by manufacturing errors, residual stress, or clamping eccentricity. This preset radial force can be applied without changing the original shape of the first spring; that is, the preset radial force is less than the force corresponding to the permanent deformation of the first spring.

[0094] Understandably, the gap fluctuation value refers to the maximum difference in radial gap or its statistical standard deviation collected from multiple measurement points along the circumference of the first spring during the application of force. It is used to quantify the roundness, coaxiality, and consistency of the spring cross-section under stress. It is important to note that even if the average gap meets the non-interference requirement, significant circumferential non-uniformity (such as ellipticization or local bulges) will cause stress concentration in the minimum gap region during subsequent reverse rotation and diameter expansion, leading to local yielding or scratches. Therefore, the gap fluctuation value is essentially a key indicator of the stability of the assembly interface, and its changing trend reflects the geometric integrity and elastic response uniformity of the spring structure.

[0095] The gap fluctuation value is obtained by real-time monitoring of the radial distance change between the two springs using a laser rangefinder or capacitive displacement sensor. The sampling frequency can be set to 100–500Hz to capture minute dynamic fluctuations. The preset duration is set according to the spring material characteristics; for example, 3–10 seconds for stainless steel springs and 5–15 seconds for titanium alloy springs due to their slower rebound, ensuring that the deformation tends to stabilize. The preset fluctuation value is related to the spring tolerance; for example, the fluctuation threshold can be set to 5%–10% of the spring wire diameter (e.g., with a wire diameter of 0.3mm, fluctuation ≤30μm is allowed), thus establishing a quality criterion that matches the product's precision level. This ensures that stress is evenly distributed circumferentially during subsequent rotation operations, avoiding structural damage caused by local abrupt changes.

[0096] By employing the aforementioned technical solution, this application effectively addresses the stress concentration problem caused by unstable gaps during assembly by adding radial force application and gap fluctuation monitoring steps before reverse rotation. Applying a preset radial force actively adjusts the contact state between springs, eliminating random fluctuations in the initial gap. This ensures a smooth transition during the nested assembly process, reduces the risk of damage to precision springs due to abnormal stress, and improves the accuracy and reliability of spring assembly.

[0097] In some of the solutions described above in this application, a technical means is proposed to reduce the diameter of the first spring to the target diameter range by rotating it in the forward direction and then stopping the rotation. However, during the rotation stopping process, there may be problems with diameter rebound or fluctuation, which makes it impossible for the first spring to be stably maintained within the target diameter range, thereby affecting the reliability of its smooth entry into the inner cavity of the second spring.

[0098] In one embodiment, such as Figure 5 As shown, step S100 also includes steps S110 and S120.

[0099] In this embodiment, step S110 involves applying a first torque in the forward direction along the winding direction of the first spring to reduce the diameter of the first spring to the target diameter.

[0100] In this embodiment, in step S120, when the diameter of the first spring is reduced to the target diameter, the process switches to applying a second torque to the first spring so that the diameter of the first spring is maintained within the target diameter range.

[0101] The application of the first torque can be achieved through a rotary drive device, such as a stepper motor or servo motor, to output torque. The range of the first torque can be 5-20 Nm, with the specific value determined based on the strength of the spring material and the target diameter. The diameter of the first spring can be monitored in real time using a laser rangefinder or image sensor. When the diameter reaches the target value, torque switching is triggered. The application of the second torque can be achieved through closed-loop control, such as dynamically adjusting the torque output using a PID algorithm. The range of the second torque can be 1-5 Nm, and its direction of action is the same as the first torque, but its intensity is reduced to counteract the elastic recovery tendency of the spring material. The switching timing between the first and second torques can be determined by a preset threshold or real-time feedback signal, for example, triggering switching when the diameter fluctuation is less than 0.1 mm.

[0102] In one feasible implementation, in the initial stage, a first torque is applied to induce plastic deformation in the spring coil, rapidly reducing the diameter to the target value. For example, when the initial spring diameter is 10 mm, a torque of 15 Nm is applied to compress the diameter to 8 mm. Subsequently, a second torque is applied, continuously applying 3 Nm of torque to counteract the spring's elastic rebound force, keeping the diameter fluctuation within ±0.05 mm. During this process, the dynamic adjustment of the second torque can be based on real-time deformation data of the spring; for example, when a sensor detects an increasing diameter trend, the torque is increased to 4 Nm to suppress rebound. Thus, the spring achieves rapid deformation during the compression phase, and during the holding phase, low-intensity torque balances material stress, preventing diameter rebound due to complete cessation of force application. This phased control method ensures that the spring diameter remains within the target range throughout the assembly process, guaranteeing the reliability of subsequent nesting actions while reducing material fatigue damage caused by over-compression.

[0103] As an optional embodiment, the solution of this application is implemented as follows: When controlling the first spring to rotate forward along the winding direction, and stopping the rotation after the diameter of the first spring has shrunk to the target diameter range, different torques can be applied in stages. First, a first torque is applied forward along the winding direction of the first spring, causing the diameter of the first spring to shrink rapidly to the target diameter. For example, a torque of 0.5 N·m can be applied by a servo motor to continuously rotate the first spring until its diameter reaches the target value. After the diameter of the first spring has shrunk to the target diameter, a second torque is applied to the first spring to maintain the diameter of the first spring within the target diameter range. Specifically, the torque of the servo motor can be reduced to 0.1 N·m, and the diameter can be kept stable within the target range by dynamically balancing the elastic restoring force of the spring material.

[0104] Through the above technical solution, this application can achieve precise control and stable maintenance of the reduction in the diameter of the first spring. The first torque provides the energy required for active compression, and the second torque forms a maintaining force to resist elastic deformation, thus avoiding material damage caused by excessive compression and preventing abnormal assembly clearance caused by diameter rebound. This staged control strategy effectively solves the contradiction between compression efficiency and dimensional stability that is difficult to achieve with a single application of force, providing precise dimensional assurance for subsequent nested assembly, thereby improving the reliability of the first spring smoothly entering the inner cavity of the second spring.

[0105] In some of the solutions described above in this application, nested assembly is achieved by controlling the axial movement of the first spring. However, if the axes of the first and second springs are not aligned, direct axial movement may cause unintended contact between the inner walls of the first and second springs, resulting in resistance to movement or damage to the spring surfaces. Alternatively, when the first spring is rotated forward along the winding direction, the axis of the first spring may shift, causing it to fail to follow a predetermined trajectory when it moves into the inner cavity of the second spring.

[0106] In one embodiment, such as Figure 6 As shown, step S200 may further include steps S231 and S232.

[0107] In this embodiment, step S231 involves adjusting the relative positions of the first spring and the second spring so that the axes of the first spring and the second spring are coaxial.

[0108] In this embodiment, step S232 involves controlling the first spring to move axially so that the first spring moves into the inner cavity of the second spring.

[0109] The relative position adjustment is achieved by detecting the coordinate difference between the center points of the two spring end faces using a visual positioning system. This drives a translation mechanism to adjust the lateral offset of one of the springs until the coordinate difference between the two centers is less than a threshold of 0.1 mm. Axial motion control can be achieved using a servo motor-driven lead screw mechanism to advance the first spring along a linear guide rail. The advancing speed can be set to 5-10 mm / s. When combined with the diameter reduction step, coaxial adjustment ensures that the outer diameter of the first spring after the diameter reduction is always within the center region of the inner diameter of the second spring, preventing one-sided contact due to eccentricity after the diameter reduction.

[0110] In one feasible implementation, after the diameter reduction step is completed, the distance between the end faces of the two springs and the offset of the center are obtained by a laser rangefinder. If the detected lateral offset exceeds 0.3 mm, the pneumatic clamp is activated to adjust the installation angle of the second spring. After coaxial calibration is completed, the linear drive mechanism pushes the first spring into the inner cavity of the second spring with a constant acceleration. At this time, since the axes are completely coincident, each coil of the first spring only bears axial compressive force and will not generate friction caused by radial component force.

[0111] As an optional embodiment, the solution of this application is implemented as follows: First, an optical sensor is used to detect the axial positions of the first spring and the second spring. Based on the detection results, a precision robotic arm adjusts the position of the first spring so that its axis is aligned with the axis of the second spring. During the adjustment process, the robotic arm can perform micrometer-level displacement adjustments in the X and Y planes until the axes of the two springs coincide.

[0112] Through the above technical solution, this application achieves precise alignment and smooth nesting of the first and second springs. By pre-adjusting the axis position, unintended contact between the springs is avoided, reducing motion resistance and the risk of surface damage.

[0113] It is understood that the first spring has a plurality of first coil groups arranged at intervals along the length direction, and the second spring has a plurality of second coil groups arranged at intervals along the length direction, each of the first coil group and the second coil group including at least one spring coil.

[0114] In this structure, an axial gap is formed between every two adjacent first coil groups, and a corresponding axial gap is also formed between every two adjacent second coil groups. These gaps constitute the spatial accommodating area in the nested spring structure, providing geometric freedom for the relative arrangement of the inner and outer springs. In an ideal nested state, the coil group of one spring should be located within the axial gap area of ​​another spring, thereby achieving a staggered structural fit and avoiding rigid collisions and concentrated loads.

[0115] In some of the solutions described above in this application, if the coil groups of the first spring and the second spring are perfectly aligned in the radial projection, it may lead to local stress concentration or assembly position deviation during nesting and matching, thereby affecting the accuracy and stability of the spring assembly.

[0116] In one embodiment, such as Figure 7 As shown, step S200 may also include steps S241 and S242.

[0117] In this embodiment, step S241 involves controlling the first spring, whose diameter is reduced to the target size, to move axially.

[0118] In this embodiment, in step S242, when multiple first coil groups and multiple second coil groups are arranged in an alternating pattern in the radial projection, the nesting and matching of the first spring and the second spring are determined, and the first spring is controlled to stop moving.

[0119] The phrase "multiple first coil groups and multiple second coil groups are staggered in radial projection" refers to the following: when viewed from the radial direction (perpendicular to the spring axis), the positions of each coil group of the first spring on the projection plane fall within the axial gap projection range between adjacent coil groups of the second spring, and vice versa; that is, the coil groups of the inner spring and the coil groups of the outer spring are axially staggered, forming a non-aligned layout similar to a "tooth-groove" fit. This staggered arrangement can effectively distribute contact loads, avoid the stress superposition effect caused by multiple coils contacting simultaneously, and improve the overall compliance and impact resistance of the structure.

[0120] It is important to note that the first and second springs are pre-fitted according to design requirements at the factory, with precise matching of their coil pitch, helix angle, and outer / inner diameter dimensions to ensure good nesting compatibility in the free state. However, during the process of the first spring reducing its diameter through forward rotation, its axial length may slightly elongate (or shorten) due to elastic deformation caused by torsional load. This results in a slight change in the coil pitch, causing a certain degree of deviation in the projected position of the actual geometry of the first spring relative to the second spring. In this case, relying directly on vision or sensors to judge the alignment of the radial projection of the coil group may lead to misjudgment of the nesting matching accuracy due to parallax introduced by deformation. To address this issue, this application does not rely on instantaneous geometric alignment under reduced diameter conditions as the assembly basis. Instead, it fully utilizes the elastic memory characteristics of the spring material. By pre-calibrating the axial elongation during the torsion process and dynamically compensating for the insertion depth in the control algorithm, it ensures that while the first spring releases torque and restores its original diameter during subsequent reverse rotation, its pitch and helical structure synchronously return to the design state. This allows the coil group to naturally fall into the corresponding gap area of ​​the second spring, achieving "self-alignment" nesting. This method eliminates the need for high-precision visual recognition under deformation conditions, avoiding the risk of misjudgment caused by projection deviations. It also leverages the physical properties of the spring itself to achieve automatic reset and precise matching of the assembly endpoint, significantly improving the reliability and repeatability of the assembly. Therefore, as long as the deviation between each coil group and its corresponding gap is less than a preset tolerance threshold (e.g., no more than 10% of the spring pitch or ±50μm, whichever is smaller), the first spring is considered to be within the recoverable matching range, satisfying the initiation condition for reverse rotation and diameter expansion. Thus, without relying on high-dynamic visual feedback, it achieves efficient and precise assembly with "error tolerance during deformation and self-alignment during recovery."

[0121] As an optional embodiment, the solution of this application is implemented as follows: Real-time images of the end faces of the first and second springs are acquired using a visual recognition system (such as a high-resolution industrial camera with a telecentric lens), the edge contours of each coil group are extracted, and their axial position coordinates are calculated; the control system determines whether the current relative position meets the projection interlacing condition based on a preset interlacing matching algorithm; for example, when the axial distance between the center position of any coil group of the first spring and the center of its nearest second spring coil group is greater than half a pitch and less than one pitch, it is determined to be in an "interlacing state"; once this condition is met, a stop command is immediately issued to terminate the axial propulsion action.

[0122] Through the above technical solution, this application achieves precise nesting and matching of the first and second springs. The staggered arrangement of the coil groups avoids localized stress concentration problems that may result from direct alignment, reducing the risk of spring deformation or damage. Simultaneously, the determination condition based on projected staggering ensures the accuracy of the assembly position, improving the stability and reliability of the spring assembly. This method is particularly suitable for the assembly requirements of precision springs and can significantly improve the performance and lifespan of spring assemblies in applications with high precision requirements, such as medical devices.

[0123] In some of the solutions described above in this application, the diameter of the first spring is enlarged by rotating it in the reverse direction and then nested and matched with the second spring. However, if the timing of stopping the reverse rotation is not precisely controlled, the first spring may generate excessive stress due to excessive rotation, resulting in damage to the spring structure or uneven stress distribution after assembly.

[0124] In one embodiment, such as Figure 8 As shown, step S300 also includes steps S310 and S320.

[0125] In this embodiment, step S310 involves applying a second torque in the opposite direction to the winding direction of the first spring.

[0126] In this embodiment, step S320 involves stopping the application of the second torque after the diameter of the first spring is enlarged and it is nested and matched with the second spring.

[0127] The applied torque is applied in the opposite direction to the spring winding direction, conforming to the spring deformation characteristics. The torque range can be set based on the material's elastic modulus; for example, the applied torque value can be controlled within the 5-10 Nm range. During assembly, the nesting matching state can be determined by real-time monitoring of the diameter change or stress value of the first spring. When the diameter reaches 95%-105% of the inner diameter of the second spring, a stop condition is triggered. Optionally, stopping the applied torque can be achieved through an electromagnetic clutch or servo motor braking to avoid stress accumulation.

[0128] In one feasible embodiment, when the second torque is applied in the opposite direction, the spring coil generates a radial expansion force due to reverse rotation, and its diameter increases linearly with the torque application time. When the first spring contacts the inner wall of the second spring, the frictional force between the contact surfaces increases with the diameter expansion. At this time, contact stress data is collected in real time by a stress sensor. For example, when the stress reaches 200-300 MPa, the nesting matching is determined to be complete. The torque input is then immediately cut off, allowing the springs to maintain a stable nested structure under the action of elastic restoring force. This process achieves precise linkage between torque application and cessation through closed-loop control, limiting the maximum stress value to below 70% of the material's yield strength, thereby avoiding plastic deformation. Thus, the tightness of the nested structure is ensured, and stress over-limit problems caused by continuous force are prevented, ultimately resulting in higher reliability and service life of the assembled spring assembly in medical devices.

[0129] Through the above technical solution, this application achieves precise control over the reverse rotation process of the spring, effectively avoiding excessive material stress caused by over-rotation. By monitoring torque parameters in real time and setting a safety threshold, the diameter expansion of the spring is ensured within the elastic deformation range, guaranteeing both tight contact in the nested assembly and preventing damage to the spring structure from plastic deformation. This control method can accurately determine the critical state of assembly completion, eliminating residual stress while forming a stable nested structure, resulting in a composite spring with uniform stress distribution and reliable structural strength.

[0130] In some of the solutions described above in this application, a technical means is proposed to expand the diameter of the first spring and nest it with the second spring before stopping the application of force. However, if the completion of assembly is used as the criterion for stopping the application of torque, the stress between the first spring and the second spring may not reach an effective matching state. Specifically, stopping the application of force too early will cause the nested structure to loosen, while stopping the application of force too late may cause fatigue of the spring material or structural deformation due to excessive stress, thereby affecting the stability of the spring performance after assembly.

[0131] In one embodiment, such as Figure 9 As shown, step S320 may also include steps S321 and S322.

[0132] In this embodiment, step S321 involves obtaining the stress between the first spring and the second spring after the diameter of the first spring is enlarged and it is nested and matched with the second spring.

[0133] In this embodiment, step S322 involves stopping the application of the second torque when the stress between the first spring and the second spring is greater than a preset stress.

[0134] The stress between the first and second springs can be obtained indirectly by a pressure sensor embedded in the spring contact surface or by calculating the relationship between the applied torque and the spring deformation. The preset stress is determined based on the yield strength, elastic modulus, and target assembly tightness of the spring material. For example, the preset stress can be set to 30%-50% of the material's yield strength. During reverse rotation, if the stress exceeds the preset value, the application of reverse torque is immediately terminated, thereby preventing insufficient stress or overload.

[0135] In one feasible implementation, after the first spring is rotated in the opposite direction to expand its diameter and nested with the second spring, the stress change in the contact area between the two springs is monitored in real time. When the stress reaches a preset threshold, it indicates that the nested structure has formed a matching state that is neither too loose nor too tight. At this point, stopping the application of force can simultaneously meet the requirements of assembly stability and material protection. For example, if the preset stress is 50 MPa, when the sensor detects that the contact stress reaches 55 MPa, the control system automatically cuts off the torque output. This scheme achieves precise control of the force termination condition through quantitative feedback of mechanical parameters, solving the problem of assembly quality fluctuations caused by subjective judgment in traditional methods, while avoiding the risk of spring fatigue or deformation caused by stress runaway.

[0136] By employing the aforementioned technical solution, this application effectively avoids the limitations of traditional methods that rely solely on the assembly completion state to determine the termination of force application. Through dynamic stress monitoring and preset threshold interlocking control, it ensures that the internal stress of the nested structure remains within the elastic deformation range of the material. This prevents loosening of the nesting structure due to insufficient force and avoids the risk of plastic deformation caused by excessive force, thereby improving the axial load uniformity and fatigue resistance of the assembled spring.

[0137] This application also provides a spring assembly system, which includes a control device that can implement the spring assembly method described above. Therefore, this spring assembly system adopts all the technical solutions of all the above embodiments, and thus has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0138] In one feasible embodiment, the control device is communicatively connected to a rotary drive module, an axial propulsion module, a vibration generation module, and a sensor group. The rotary drive module is configured to apply a forward or reverse rotational torque to the first spring. The axial propulsion module drives the first spring to move axially along the second spring. The vibration generation module includes a piezoelectric actuator to generate axial vibration. The sensor group includes a pressure sensor, a displacement sensor, and a stress sensor. The control device receives real-time motion resistance data from the pressure sensor. When the resistance exceeds a preset threshold, it triggers the vibration generation module to provide vibration assistance with a frequency range of 50-200Hz and an amplitude range of 0.1-0.5mm. The displacement sensor monitors the insertion depth of the first spring. The control device dynamically reduces the vibration frequency and amplitude based on the depth-vibration parameter mapping relationship, wherein for every 1mm increase in depth, the frequency decreases by 5Hz and the amplitude decreases by 0.02mm. After axial movement is completed, the radial preload module applies a radial compressive force to the first spring. The gap sensor detects the fluctuation value between the two springs. When the fluctuation value is below 0.05mm for 3 consecutive seconds, the control device initiates a reverse rotation program. The stress sensor monitors the stress changes in real time during the nested matching process. When the stress value reaches 70% of the material's yield strength, the control device immediately terminates the reverse torque output.

[0139] The above technical solution effectively solves the problems of insufficient multi-step coordination and lag in parameter adjustment. Through real-time data interaction and linkage control of each module, precise matching of rotational torque, vibration parameters, and propulsion depth is achieved. The dynamic adjustment mechanism ensures the uniformity of stress distribution during nesting, avoiding plastic deformation of the spring caused by local stress concentration. Automated closed-loop control significantly improves assembly efficiency while ensuring the repeatability and structural reliability of precision spring nesting.

[0140] In one feasible embodiment, the spring assembly system can be used in a medical device including a first spring and a second spring. The second spring can be fixed to a corresponding position on the assembly system, such as an assembly table. The spring assembly system can nest and match the first spring with the second spring using a corresponding spring assembly method. This reduces the stress on the nested springs in the medical device during the nesting process, increasing their service life. Of course, this spring assembly system can also be used in other devices requiring precise spring nesting assembly, and is not specifically limited here.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no technical conflict, the various technical features mentioned in the various embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A spring assembly method, characterized in that, The spring assembly method includes: Control the first spring to rotate in the forward direction along the winding direction so that the diameter of the first spring is reduced to the target diameter range; The first spring, whose diameter is reduced to the target size, moves into the inner cavity of the second spring, wherein the maximum value of the target diameter range is less than the diameter of the second spring; Control the first spring to rotate in the opposite direction along the winding direction so that the diameter of the first spring is enlarged and it is nested and matched with the second spring for assembly; The process of controlling the first spring to shrink its diameter to the target size and moving it into the inner cavity of the second spring further includes: When the first spring moves into the inner cavity of the second spring, the resistance to the movement of the first spring is obtained; When the resistance of the first spring exceeds the preset resistance, the first spring is controlled to vibrate axially within the preset frequency range and the preset amplitude range. The process of controlling the first spring to shrink its diameter to the target size and moving it into the inner cavity of the second spring further includes: Obtain the depth of the first spring moving into the inner cavity of the second spring and a preset depth-vibration parameter mapping table, wherein the vibration parameters include amplitude and frequency; Based on the depth of the first spring moving into the inner cavity of the second spring and a preset depth-vibration parameter mapping table, the first spring is controlled to vibrate axially with corresponding amplitude and frequency; wherein, the depth of the first spring moving into the inner cavity of the second spring is negatively correlated with frequency and amplitude. The method further includes, after controlling the first spring to rotate forward along the winding direction to reduce the diameter of the first spring to the target diameter range, and before the first spring, whose diameter has been reduced to the target size, moves into the inner cavity of the second spring: A preset radial force is applied to the first spring toward the inner cavity of the first spring, and the gap fluctuation value between the first spring and the second spring is obtained; After a preset time, and if the gap fluctuation value is less than the preset fluctuation value, it is determined that the first spring, which controls the diameter to shrink to the target size, moves to the inner cavity of the second spring.

2. The spring assembly method as described in claim 1, characterized in that, Controlling the first spring to rotate forward along the winding direction, so that the diameter of the first spring is reduced to a target diameter range and then stopping the rotation includes: A first torque is applied in the positive direction along the winding direction of the first spring to reduce the diameter of the first spring to the target diameter; When the diameter of the first spring is reduced to the target diameter, the process switches to applying a second torque to the first spring so that the diameter of the first spring remains within the target diameter range.

3. The spring assembly method as described in claim 1, characterized in that, The movement of the first spring, whose diameter is reduced to the target size, into the inner cavity of the second spring includes: Adjust the relative positions of the first spring and the second spring so that the axes of the first spring and the second spring are coaxial; The first spring is controlled to move axially so that it moves into the inner cavity of the second spring.

4. The spring assembly method as described in claim 3, characterized in that, The first spring has a plurality of first coil groups spaced apart along the length direction, and the second spring has a plurality of second coil groups spaced apart along the length direction, each of the first coil group and the second coil group including at least one spring coil. The movement of the first spring, whose diameter is reduced to the target size, into the inner cavity of the second spring includes: The first spring, whose diameter is reduced to the target size, moves axially. When multiple first coil groups and multiple second coil groups are staggered in radial projection, the nesting and matching of the first spring and the second spring are determined, and the first spring is controlled to stop moving.

5. The spring assembly method as described in claim 1, characterized in that, Controlling the first spring to rotate in the opposite direction of the winding direction, so as to enlarge the diameter of the first spring and to nest and match it with the second spring, includes: A second torque is applied in the opposite direction to the winding direction of the first spring; After the diameter of the first spring is enlarged and it is nested and matched with the second spring, the application of the second torque is stopped.

6. The spring assembly method as described in claim 5, characterized in that, The step of stopping the application of the second torque after the diameter of the first spring is enlarged and it is nested and matched with the second spring includes: After the diameter of the first spring is enlarged and it is nested and matched with the second spring, the stress between the first spring and the second spring is obtained. When the stress between the first spring and the second spring exceeds the preset stress, the application of the second torque is stopped.

7. A spring assembly system, characterized in that, The spring assembly system includes a control device configured to implement the spring assembly method as described in any one of claims 1 to 6.

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