Method and apparatus for removing residual stresses in a retainer

Abstract

The application discloses a method and equipment for removing the residual stress of a retainer, which comprises the steps of positioning and profiling clamping, oval deformation, S-shaped stress relief, whole circle and the like. In the oval deformation step, a profiling pressure roller applies pressure to the retainer to make it generate oval deformation, so that the roundness tolerance is increased, which creates favorable conditions for subsequent stress relief treatment. By actively expanding the roundness tolerance, more space and possibility are provided for stress release and shape remodeling. The S-shaped deformation stress relief mode can promote the large-scale redistribution of the internal stress of the retainer material and reach a new balance state. In the final circle correction step, the profiling wheel body is adjusted to the standard outer circle size position of the retainer product, and the retainer is rotated to generate permanent plastic deformation again. Through the fine adjustment process, the roundness of the retainer is accurately corrected to the qualified standard, so that the stability and reliability of the product quality are ensured.

Description

Technical Field

[0001] This application belongs to the field of bearing cage roundness correction, and particularly relates to a method and apparatus for removing residual stress from the cage. Background Technology

[0002] In the bearing manufacturing industry, the bearing cage is a core component, and its geometric accuracy has a decisive impact on the overall performance and operational stability of the bearing. Roundness, as a key indicator of cage quality, directly affects the bearing's rotational accuracy, vibration amplitude, and service life. Taking finished tapered cages (product diameter 1.5-3mm) as an example, their roundness requirements are extremely stringent, typically specified to be ≤1.0mm. However, in actual production, due to the inherent limitations of the processing technology, the inherent characteristics of the materials, and the stress release during processing, the roundness of currently produced tapered cages generally exceeds the standard, with actual measurements mostly concentrated in the 1.5-3.0mm range. Excessive roundness will cause uneven stress on the bearing during operation, leading to increased vibration, increased noise, and severe overheating, seriously affecting bearing performance and reliability, and even causing premature bearing failure, posing a hidden danger to the safe operation of equipment.

[0003] To address the issue of out-of-tolerance roundness in tapered cages, improve product quality, and ensure normal bearing operation, tooling is needed to correct the out-of-tolerance cages, bringing their roundness to the acceptable standard. Because the difference between the out-of-tolerance cage and the standard roundness is small, the correction amount is very minute, resulting in a relatively small force applied to the cage. This weak force can only make minor adjustments to a localized area of ​​the cage and cannot generate sufficient force to drive a large-scale redistribution of internal stress within the material. While this minor shaping operation alters the local shape of the cage, temporarily restoring its roundness to the standard, it lacks sufficient force and space for the internal stress to redistribute and reach a new equilibrium. This leads to poor stability after shaping, indicating that existing technology needs further improvement. Summary of the Invention

[0004] This invention provides a method and apparatus for removing residual stress in a cage, which solves the problem that although cage rounding can make local fine adjustments, it cannot solve the problem of residual stress inside the material, resulting in a high roundness rebound rate and poor stability after correction.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for removing residual stress from a cage includes the following steps:

[0007] S1: Positioning and contour clamping: The round cage is precisely placed in the clamping space formed by multiple contouring rollers, and the contouring rollers match the contour of the cage; through the close fit between the contouring rollers and the inner and outer contours of the cage, the cage is stably clamped, and the cage can rotate smoothly as the contouring rollers rotate.

[0008] S2: Elliptical Deformation: The contouring roller applies pressure to the cage, causing the cage to undergo elliptical deformation, increasing the roundness deviation; at the same time, it ensures that the cage can rotate normally under the drive of the contouring roller.

[0009] S3: S-shaped stress relief: The conforming pressure roller drives the cage, which undergoes elliptical deformation, to rotate for a set time. During the elliptical rotation, the outer conforming pressure roller applies pressure towards the two inner conforming pressure rollers, or the inner conforming pressure roller applies pressure towards the two outer conforming pressure rollers, causing local deformation of the ellipse. As it rotates, the deformed part contacts the inner or outer conforming pressure rollers and recovers, forming an S-shaped deformation, achieving stress relief, stabilizing the elliptical shape, and promoting permanent plastic deformation of the cage, thereby initially improving the roundness of the cage.

[0010] S4: Rounding: Adjust all the contour wheels in contact with the cage to the standard outer diameter of the cage product; rotate the cage again for the design time to allow it to undergo permanent plastic deformation in the new dimensional position; through this step, the roundness of the cage is finally made to meet the qualified standard.

[0011] The above method utilizes multiple contour-following pressure rollers that match the cage's profile to create a clamping space. This close fit to the cage's inner and outer contours ensures stable clamping, guaranteeing not only precise positioning of the cage during subsequent processing but also providing a foundation for its smooth rotation. This avoids processing errors caused by unstable clamping and ensures the accuracy of the entire roundness correction process. In the elliptical deformation step, the contour-following pressure rollers apply pressure to the cage, causing elliptical deformation and increasing the roundness deviation. This creates favorable conditions for subsequent stress relief treatment. By actively expanding the roundness deviation, it provides greater space and possibilities for stress release and shape reshaping. During elliptical rotation, alternating pressure from inner and outer contouring rollers creates localized deformation. As the deformed portion recovers, it forms an S-shaped deformation. This unique stress-relief method promotes a large-scale redistribution of internal stress within the cage material, achieving a new equilibrium. Compared to traditional micro-shaping operations, this fundamentally solves the stability problem caused by insufficient stress release, leading to permanent plastic deformation of the cage and initial improvement in roundness. The final roundness correction step adjusts the contouring rollers to the standard outer diameter of the cage, causing further permanent plastic deformation during cage rotation. Through this meticulous adjustment process, the roundness of the cage is precisely corrected to the acceptable standard, ensuring product quality stability and reliability. The entire method is tightly interconnected, from stable clamping to active deformation, stress relief, and precise roundness correction, forming a complete conical cage roundness correction system. This effectively solves the problems existing in current technologies, significantly improving the product quality of conical cages and the stability of bearing operation.

[0012] In the preferred implementation, in step S2, the contouring pressure roller can dynamically adjust its relative position with the cage. The contouring pressure roller moves precisely a preset design distance in the direction toward the center of the cage, applying controllable pressure to the cage and causing the cage to produce an elliptical deformation. The major axis dimension of the elliptical deformation is denoted as D2, the minor axis dimension is denoted as D2, and D1 < D3 < D2 is satisfied.

[0013] In a preferred implementation, the relative deformation ratio between the moving distance of the contouring pressure roller and the diameter of the cage in step S2 is in the range of 0.7%-2%.

[0014] In the preferred implementation, in step S2, the contouring rollers that contact the outer and inner sides of the cage both move in the direction toward the center of the cage; the moving speed of the inner contouring roller toward the center is less than the moving speed of the outer contouring roller toward the center.

[0015] In a preferred implementation, during steps S3 and S4, the cage is heated, and the cage is synchronously driven to rotate during the heating process.

[0016] In the preferred implementation, the following steps are also included:

[0017] S5: Staged cooling process: After the cage deformation is completed in step S4, it is first naturally cooled to below 200°C, and then forced cooling is used to room temperature;

[0018] S6: Vibration: While performing step S5, use a vibration aging treatment cage with a vibration frequency of 50-200Hz.

[0019] The equipment used in the method for removing residual stress in the cage includes a limiting wheel for limiting the product, a driving wheel that can drive the product to rotate, a pressing wheel that can adjust the roundness of the product opening, a driving height limiting wheel that abuts against the upper surface of the cage, and a bottom flat reference wheel that abuts against the lower surface of the cage; the outer contour shape of the pressing wheel, the driving wheel, and the limiting wheel is adapted to the outer wall shape of the cage.

[0020] The extrusion wheel, the drive wheel, and the limit wheel each include two sets of wheels, one inner and one outer.

[0021] The extrusion wheel, drive wheel, and limit wheel are all movably mounted on the adjustment base;

[0022] The cage is positioned in the clamping space formed between the inner and outer extrusion wheels, the drive wheel, and the limit wheel, with the extrusion wheels, drive wheel, and limit wheel in contact with the inner and outer wall contours of the cage.

[0023] In a preferred implementation, the longitudinal axis and the transverse axis are set with the center of the cage as the center. The extrusion wheel and the limiting wheel are symmetrically distributed relative to the longitudinal axis. No wheel body is set at the straight position of the longitudinal axis. The drive wheel is symmetrically distributed relative to the transverse axis or the extrusion wheel and the limiting wheel are connected to drive the active rotation.

[0024] In the preferred implementation, the inner and outer wheel bodies are spaced apart.

[0025] In a preferred implementation, an inductor coil is set on the base, and the cage is placed inside the inductor coil to achieve electromagnetic induction heating of the cage / extrusion wheel, limit wheel, or drive wheel. The wheel body is equipped with a heating wire, and copper plates are respectively set at both ends of the wheel body. The copper plates are electrically connected to the heating wire. It also includes two brushes, the positions of which correspond to the copper plates at both ends of the wheel body. When the wheel body is installed on the base, the brushes are in contact with the copper plates. The brushes are electrically connected to an external power supply. During the rotation of the wheel body, the brushes remain stationary, and the wheel body can rotate freely. Attached Figure Description

[0026] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and, together with their description, serve to explain this application and do not constitute an undue limitation of the invention. In the drawings:

[0027] Figure 1A schematic diagram illustrating one embodiment of the cage elliptical deformation in the cage residual stress removal method of this application is shown.

[0028] Figure 2 This illustration shows a schematic embodiment of the cage local S-shaped deformation stress relief method of the cage in this application.

[0029] Figure 3 This illustration shows a schematic embodiment of the cage rounding method for removing residual stress in the cage according to this application;

[0030] Figure 4 A schematic diagram illustrating one embodiment of the cage residual stress removal device of this application is shown;

[0031] Figure 5 A schematic diagram illustrating one embodiment of the inner extrusion wheel and inner limiting wheel of this application is shown;

[0032] Figure 6 A schematic diagram illustrating one embodiment of the active wheel of this application is shown;

[0033] Figure 7 A schematic diagram illustrating one embodiment of the heating wire installed inside the wheel body of this application is shown;

[0034] Label Explanation:

[0035] 10. Outer contouring pressure roller; 11. Inner contouring pressure roller; 20. Outer extrusion roller; 21. Outer limiting roller; 22. Inner extrusion roller; 23. Inner limiting roller; 24. Active height limiting roller; 25. Bottom flat reference roller; 26. Active roller; 260. Rotating motor; 261. First tooth body; 262. Second tooth body; 263. Heating wire; 264. Copper sheet; 265. Brush; 30. Adjusting base. Detailed Implementation

[0036] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit and scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0037] The present invention will now be described with reference to the accompanying drawings.

[0038] The specific solution adopted is as follows:

[0039] like Figure 1-7 As shown, the present invention provides a method for removing residual stress in a cage, comprising the following steps:

[0040] S1: Positioning and contour clamping: The round cage is precisely placed in the clamping space formed by multiple contouring rollers, and the contouring rollers match the contour of the cage; through the close fit between the contouring rollers and the inner and outer contours of the cage, the cage is stably clamped, and the cage can rotate smoothly as the contouring rollers rotate.

[0041] The cage to be rounded is precisely placed within a clamping space formed by multiple contouring rollers. These rollers match the cage's contour, ensuring the cage remains in the correct position during subsequent machining. The close fit between the contouring rollers and the cage's inner and outer contours—for example, cylindrical rollers for cylindrical cages and frustum-shaped rollers for conical cages—and the contouring rollers corresponding to the flanged end rings of conical cages (i.e., a smaller cylindrical frustum at the top of the frustum) provides stable clamping. This stable clamping prevents displacement or wobbling during machining, ensuring precision and stability. As the contouring rollers rotate, the cage rotates smoothly. This smooth rotation ensures that all parts of the cage are evenly stressed during machining.

[0042] S2: Elliptical Deformation: The contouring roller applies pressure to the cage, causing the cage to undergo elliptical deformation, increasing the roundness deviation; at the same time, it ensures that the cage can rotate normally under the drive of the contouring roller.

[0043] The conforming pressure roller applies pressure to the cage, causing it to deform into an elliptical shape, further increasing the roundness deviation. This step, seemingly contrary to the goal of achieving complete roundness, aims to promote internal stress transfer and redistribution. Compared to traditional local fine-tuning, triggering stress release through overall deformation allows for controlled elliptical deformation of the cage. By appropriately controlling the pressure and degree of deformation, it's possible to ensure the cage can still rotate normally while undergoing this controlled elliptical deformation. Normal rotation ensures that all parts of the cage are subjected to uniform force, resulting in more uniform stress release and shape adjustment during the elliptical deformation process. During rotation, each part of the cage sequentially passes through the area of ​​action of the conforming pressure roller, experiencing uniform pressure and deformation.

[0044] S3: S-shaped stress relief: The conforming pressure roller drives the cage, which undergoes elliptical deformation, to rotate for a set time. During the elliptical rotation, the outer conforming pressure roller applies pressure towards the two inner conforming pressure rollers, or the inner conforming pressure roller applies pressure towards the two outer conforming pressure rollers, causing local deformation of the ellipse. As it rotates, the deformed part contacts the inner or outer conforming pressure rollers and recovers, forming an S-shaped deformation, achieving stress relief, stabilizing the elliptical shape, and promoting permanent plastic deformation of the cage, thereby initially improving the roundness of the cage.

[0045] The elliptical deformation and S-shaped deformation steps are closely linked and work together on the cage, with elliptical deformation being a prerequisite for S-shaped deformation. This step creates the conditions for subsequent S-shaped deformation, as S-shaped deformation is more effective only when there is uneven stress distribution within the cage. S-shaped deformation is performed based on elliptical deformation. The conforming pressure roller drives the cage, which has undergone elliptical deformation, to rotate. During this elliptical rotation, the ellipse is locally deformed. As it rotates, the deformed portion contacts other inner or outer conforming pressure rollers and recovers, forming an S-shaped deformation. Through this process of localized deformation and recovery, S-shaped deformation allows for a more thorough release of stress within the cage. Although some stress release is triggered during elliptical deformation, some stress concentration areas still exist. S-shaped deformation further releases the stress in these areas, thereby reducing the risk of shape changes due to stress concentration.

[0046] Because the S-shaped deformation causes permanent plastic deformation of the cage, the shape of this deformation is fixed. Under the new stress equilibrium state, the elliptical shape of the cage is no longer easily changed by changes in internal stress, thus maintaining the stability of the elliptical shape. This initially improves the roundness of the cage and creates favorable conditions for subsequent rounding steps.

[0047] S4: Rounding: Adjust all the contour wheels in contact with the cage to the standard outer diameter of the cage product; rotate the cage again for the design time to allow it to undergo permanent plastic deformation in the new dimensional position; through this step, the roundness of the cage is finally made to meet the qualified standard.

[0048] The ellipse has a greater difference in roundness compared to the original cage and the standard circle, meaning there is a more significant shape difference between the ellipse and the standard circle. During the rounding process, this larger roundness difference provides ample space for deformation. During the S-shaped deformation, the stress inside the cage is released and redistributed, forming a stable elliptical shape. At this point, the stress distribution within the ellipse is relatively uniform and stable. This stable stress distribution provides favorable conditions for the rounding step, as it eliminates the need to expend significant effort addressing stress concentration and uneven stress distribution. Due to the stable stress distribution within the ellipse, stress changes are relatively controllable during further deformation adjustments to the cage during the rounding process. When the conforming wheel in contact with the cage is adjusted to the standard outer circle dimension, causing permanent plastic deformation of the cage in the new dimension, sudden stress concentration or uncontrolled deformation will not occur due to uneven stress distribution.

[0049] During the rounding process, the cage undergoes permanent plastic deformation at its new dimensional position. Plastic deformation is an irreversible process; once the material enters the plastic deformation stage, the shape of the cage is no longer easily altered by changes in internal stress or slight external forces. Even if the external force is removed, the material cannot completely return to its original shape. This irreversibility ensures the stability of the cage's shape after rounding, ultimately ensuring that the cage's roundness meets the acceptable standard and stabilizes.

[0050] In a preferred embodiment of this application, in step S2, the contouring pressure roller can dynamically adjust its relative position with the cage. The contouring pressure roller moves precisely a preset design distance in the direction toward the center of the cage, applying controllable pressure to the cage and causing the cage to produce an elliptical deformation. The major axis dimension of the elliptical deformation is denoted as D2, the minor axis dimension is denoted as D2, and D1 < D3 < D2 is satisfied.

[0051] Furthermore, in step S2, the relative deformation ratio between the traveling distance of the contouring roller and the diameter of the cage ranges from 0.7% to 2%.

[0052] The deformation range is set between 0.7% and 2% to ensure that the cage can produce sufficient deformation to adjust roundness without causing excessive deformation of the material that could lead to cracking or damage. If the deformation range is too small, it may not be able to effectively improve roundness; if the deformation range is too large, it may exceed the material's tolerance limit, leading to cracks or other defects in the cage.

[0053] The product model TSSF-8224 was selected for verification (product parameters: material: S355MC, product diameter: 2163, product angle: 18°54′, product thickness: 13, product height: 174). This material has certain strength and toughness.

[0054] The processing steps (taking 8224 as an example) involve adjusting the contouring roller to move 20-30mm toward the center, resulting in an elliptical product (D1 < D3 < D2). The stress relief step involves rotating for 10 minutes to redistribute stress and induce permanent plastic deformation, which alters the roundness of the product.

[0055] Finally, adjust all the contacting wheels to the "standard outer diameter D3 position of product 8224", rotate for 10 minutes to allow the product to undergo permanent plastic deformation.

[0056] After the rounding process is completed, the cage undergoes an initial roundness test. A high-precision roundness tester is used to select multiple representative measurement sections and points on the cage surface to comprehensively and accurately measure its roundness error. The test results show that the roundness of the cage has been significantly improved after the rounding process, meeting the roundness standard specified in the product design, which fully demonstrates the effectiveness of the rounding process.

[0057] To further verify the stability of the cage's roundness, the cages that passed the initial inspection were left to stand for a period of time. During this period, the cages may be affected by factors such as the release of residual stress within the material and changes in ambient temperature and humidity. After a sufficiently long period, the roundness of the cages was tested again. The test data showed that the roundness of the cages did not rebound and remained stably within the acceptable range. This indicates that the permanent plastic deformation formed during the rounding process has good stability and can resist interference from various potential factors, ensuring that the cages maintain high-precision roundness throughout long-term use.

[0058] In the example above, the product diameter D = 2163 mm, and the distance the extrusion roller moves towards the center is within the range of 20-30 mm. r1 = Extrusion roller movement distance / Product diameter.

[0059] When the extrusion roller travels 20mm, substituting the extrusion roller travel distance of 20mm and the product diameter of 2163mm into the formula, we get: r1≈0.00925, which can be converted into percentage form as r1≈0.925%.

[0060] When the extrusion roller travels 30mm, substituting the extrusion roller travel distance of 30mm and the product diameter of 2163mm into the formula, we get: r2≈0.01387, which can be converted into percentage form as r2≈1.387%.

[0061] Calculations show that the ratio of the extrusion roller travel distance to the product diameter is approximately 0.925%. - The value is between 1.387%. This ratio falls within the previously mentioned deformation ratio range of 0.7%-2%, indicating that for product model TSSF-8224, the processing parameter setting of moving the extrusion roller 20-30mm towards the center is reasonable. It can ensure that the cage produces sufficient deformation to adjust the roundness while preventing excessive deformation of the material that could lead to breakage or damage, and it also meets the requirements for processing stability.

[0062] In summary, the stress is redistributed evenly, and the ratio of the moving distance (20-30mm) to the cage diameter (1.5m-2.8m, i.e., 1500-3000mm) reflects a relatively low degree of deformation. Due to the small relative deformation, although the product becomes elliptical (D1 < D3 < D2) after the extrusion roller is moved towards the center, this deformation does not cause the product to lose its basic rotational ability. The small relative deformation does not destroy the overall structural stability of the product; only the local shape is changed.

[0063] As the extrusion rollers move towards the center, the product is compressed, altering its internal stress state. Due to the relatively small movement distance, the stress redistribution process is relatively gentle. During the 10-minute rotation, the stress gradually becomes more evenly distributed, while the product undergoes permanent plastic deformation to change its roundness. The small movement distance prevents excessive stress concentration, avoiding cracking or excessive deformation of the product due to excessive localized stress.

[0064] Under the influence of stress redistribution and permanent plastic deformation, the roundness of the product is improved to a certain extent. Although the initial deformation worsens the roundness, through subsequent adjustments and rotation, the product gradually approaches the standard roundness. The ratio of the movement distance to the cage diameter determines the stress distribution and the degree of deformation. A smaller movement distance makes the deformation process controllable, which is beneficial for ultimately achieving qualified roundness.

[0065] In a preferred embodiment of this application, in step S2, the contouring rollers that contact the outer and inner sides of the cage move in the direction toward the center of the cage; the moving speed of the inner contouring roller 11 toward the center is less than the moving speed of the outer contouring roller 10 toward the center.

[0066] The outer contouring roller 10 moves at a faster speed, initially applying force to the outer side of the cage. However, due to the slower movement of the inner contouring roller 11, the overall deformation of the cage is initially limited. This design ensures that deformation does not occur instantaneously or violently, but rather through a gradual induction process. This gradual deformation allows the cage material time to adjust and rearrange its microstructure, preventing internal cracks or damage caused by sudden, violent deformation, and contributing to a more uniform stress distribution within the cage. When the outer roller applies force first, it generates stress on the outer side of the cage. The slow movement of the inner roller allows the stress to gradually transfer and diffuse inward, preventing excessive stress concentration in any localized area. A uniform stress distribution means that the forces borne by different parts of the cage are relatively balanced, preventing damage to any part due to excessive stress.

[0067] If the inner and outer contouring rollers 10 move rapidly towards the center simultaneously, or if the inner roller moves at a speed greater than the outer roller, a large instantaneous impact force will be generated on the cage. This impact force may far exceed the cage material's bearing capacity, causing the cage to rupture instantly or suffer irreparable deformation. By using different speeds for the inner and outer rollers, this instantaneous impact force is avoided, allowing the cage to deform gradually under relatively gentle force. Cages made of different materials have different mechanical properties and deformation characteristics. Although steels such as S355MC have certain strength and ductility, they may still be damaged under severe deformation. This method of different speeds for the inner and outer contouring rollers 10 better adapts to the characteristics of the material.

[0068] In a preferred embodiment of this application, in steps S3 and S4, the cage is heated and the cage is synchronously driven to rotate during the heating process.

[0069] The yield strength of a material decreases with increasing temperature. At high temperatures, the atomic mobility within the material increases, and grain slippage is easier. This allows the cage material to better adapt to shape changes during deformation, reducing the risk of cracks or breakage due to excessive deformation. Synchronous cage rotation further promotes uniform stress distribution, reducing material damage or fatigue problems during subsequent use caused by excessive localized stress.

[0070] Furthermore, it also includes the following steps,

[0071] S5: Staged cooling process: After the cage deformation is completed in step S4, it is first naturally cooled to below 200°C, and then forced cooling is used to room temperature;

[0072] S6: Vibration: While performing step S5, use a vibration aging treatment cage with a vibration frequency of 50-200Hz.

[0073] If rapid forced cooling is applied directly, the inconsistent cooling rates between the cage surface and interior will generate significant thermal stress. This thermal stress can lead to defects such as deformation and cracking of the cage. However, by first allowing natural cooling to below 200°C, the overall temperature of the cage decreases slowly, giving the material sufficient time for heat conduction and reducing the temperature gradient. When forced cooling is then applied, thermal stress can be effectively controlled, reducing the risk of cage damage.

[0074] Simultaneously with step S5, the cage undergoes vibration aging treatment at a frequency of 50-200Hz. Vibration aging involves applying alternating vibration loads to the cage using a vibration device, causing microscopic plastic deformation within the cage, thereby eliminating or reducing residual stress. The selection of the vibration frequency needs to be adjusted based on factors such as the cage's material, shape, and size to ensure optimal aging treatment results.

[0075] The equipment used in the method for removing residual stress in the cage includes a limiting wheel for limiting the product, a drive wheel 26 that can drive the product to rotate, a pressing wheel that can adjust the roundness of the product opening, a drive height limiting wheel 24 that abuts against the upper surface of the cage, and a bottom flat reference wheel 25 that abuts against the lower surface of the cage; the outer contour shape of the pressing wheel, the drive wheel 26, and the limiting wheel is adapted to the outer wall shape of the cage.

[0076] The extrusion wheel, the drive wheel 26, and the limit wheel each include two sets of wheels, one inner and one outer;

[0077] See Figure 4 The outer extrusion roller 20, the outer drive roller 26, and the outer limit roller 21 are all movably mounted on the adjustment base 30. Specifically, the adjustment base 30 has movable slots, including an extrusion roller movable slot for mounting the outer extrusion roller 20, a drive roller movable slot for mounting the outer drive roller 26, and a limit roller movable slot for mounting the outer limit roller 21. It is worth mentioning that the extending direction of the extrusion roller movable slot is perpendicular to the extending direction of the drive roller 26 movable slot and the extending direction of the limit roller movable slot.

[0078] A ball screw drive mechanism is configured inside the moving groove, and this ball screw drive mechanism works in conjunction with a servo motor. The bases of the outer pressing wheel 20, the outer limit wheel 21, and the outer driving wheel 26 are all connected to the moving part of the ball screw drive mechanism. When the screw rotates, the base can move along the corresponding moving groove.

[0079] By combining a ball screw drive mechanism with a servo motor, and electrically connecting the servo motor to the controller, intelligent control of the movement distance is achieved. Combined with the vertical layout of the moving slot, high-precision, high-dynamic, and high-stability movement control of the outer extrusion roller 20, outer drive roller 26, and outer limit roller 21 is realized. This control method can meet the micron-level precision requirements for cage roundness correction, ensuring consistency in the processing technology. Simultaneously, it supports real-time adjustment and multi-condition collaborative operation, which is beneficial for improving production efficiency and flexibility.

[0080] See Figure 4 and Figure 5 The inner extrusion roller 22 and the inner limit roller 23 are respectively mounted on two arc-shaped plates, with a certain gap between the two arc-shaped plates. Each arc-shaped plate is connected to a ball screw mechanism, specifically to the moving part of the screw. In this way, when the servo motor equipped with one of the ball screw mechanisms drives the screw to rotate, the arc-shaped plate connected to it will move, thereby driving the inner extrusion roller 22 and the inner limit roller 23 mounted on that arc-shaped plate to move together.

[0081] See Figure 4 With the center of the cage as the center, the longitudinal axis and the transverse axis are set. The extrusion wheel and the limiting wheel are symmetrically distributed relative to the longitudinal axis. No wheel body is set at the straight position of the longitudinal axis. The driving wheel 26 is symmetrically distributed relative to the transverse axis or the extrusion wheel and the limiting wheel are connected to drive the active rotation.

[0082] This layout offers significant advantages when the cage undergoes elliptical deformation. During elliptical deformation, the cage deforms in different directions, with the longitudinal axis typically forming the major axis of the ellipse. Since there are no wheel obstructions along the longitudinal axis, the cage can deform more freely at the major axis point, allowing the main deformation path to extend smoothly as expected, avoiding problems such as uneven deformation or localized stress concentration caused by wheel obstruction.

[0083] The drive wheels 26 are symmetrically distributed relative to the transverse axis. The drive wheels 26 play a driving and guiding role in the cage's machining process. This symmetrical distribution relative to the transverse axis ensures a uniform driving force in the cage's transverse direction, maintaining stable motion during rotation and deformation. This symmetrical distribution helps ensure uniform stress distribution on the cage during elliptical deformation, avoiding deformation deviations caused by uneven stress.

[0084] Another approach is to connect the extrusion wheel and the limit wheel to a drive unit to achieve active rotation. When the extrusion wheel and the limit wheel rotate actively, they not only limit and guide the deformation of the cage, but also drive the cage to rotate through friction with the cage surface, thus meeting the performance requirements of the cage in various application scenarios.

[0085] Furthermore, when radial pressure is applied by the extrusion rollers, the cage may warp or shift in the height direction (axial direction) due to material elasticity or uneven stress distribution. The active height limiting roller 24 directly restricts axial displacement through rigid contact, ensuring that deformation is strictly controlled within the radial plane and avoiding three-dimensional deformation during the "ellipticization" process. Specifically, the active height limiting roller 24 has a first position and a second position; when the active height limiting roller 24 is in the first position, its axial direction is parallel to the axial direction of the cage, so as to facilitate placing the cage in the corresponding position in the device; when the active height limiting roller 24 is in the second position, its axial direction is perpendicular to the axial direction of the cage, so as to press the upper edge of the cage, thereby limiting the height of the cage.

[0086] In the specific implementation, the active height limiting wheel 24 is rotatably mounted on the fixed rod, and the two are connected by rotating components such as bearings, allowing the active height limiting wheel 24 to rotate freely around the fixed rod. The fixed rod is vertically connected to one end of the rotating rod, and the two can be fixed by welding, threaded connection, or other methods to ensure a firm and reliable connection. The other end of the rotating rod is rotatably connected to the base, which is fixedly installed in a suitable position of the device to provide stable support for the entire rotating structure. The rotating rod and the base are also connected by rotating components such as bearings, allowing the rotating rod to rotate freely around the base.

[0087] Driven by external force, the rotating rod rotates around the base, causing the fixed rod and the active height limiting wheel 24 to rotate together. This allows the active height limiting wheel 24 to switch its axial direction between the direction parallel to the cage axis (first position) and the direction perpendicular to the cage axis (second position). This switching method is simple and flexible, and can quickly adapt to different working requirements. To ensure that the active height limiting wheel 24 remains stably in the first and second positions, a detachable anti-rotation structure is provided on the base and the rotating rod. For example, two positioning holes are provided on the base, corresponding to the first and second positions of the active height limiting wheel 24, respectively; and a retractable positioning pin is provided on the rotating rod. When the active height limiting wheel 24 rotates to the desired position, the positioning pin is inserted into the corresponding positioning hole to prevent the rotating rod from continuing to rotate, thereby limiting the position of the active height limiting wheel 24. When it is necessary to switch positions, simply pull out the positioning pin, rotate the rotating rod to the target position, and then insert the positioning pin into the corresponding positioning hole.

[0088] See Figure 6 The drive wheel 26 includes a shaft, a wheel body sleeved outside the shaft, the shaft is rotatably mounted on the base, the shaft is provided with a second tooth 262, a rotary motor 260 is provided on the moving part of the lead screw, the output rod of the rotary motor 260 is provided with a second tooth 262, the first tooth 261 and the second tooth 262 mesh with each other, thereby realizing the active rotation of the drive wheel 26.

[0089] See Figure 4 The inner and outer wheel bodies are spaced apart to allow for independent driving of a single extrusion wheel to move between the two inner extrusion wheels 22 to apply pressure and perform step S3.

[0090] In one method of heating the cage, an inductor coil is installed on the base, and the cage is placed inside the inductor coil to achieve electromagnetic induction heating of the cage. The electromagnetic coil is located outside the moving slot, for example, using a U-shaped structure with one side opening. The cage is placed inside the space enclosed by the U-shaped electromagnetic coil, and heating of the cage is achieved through the principle of electromagnetic induction.

[0091] See Figure 7 The extrusion wheel, limit wheel, or drive wheel 26 has an electric heating wire 263 inside its body. Copper sheets 264 are respectively provided at both ends of the wheel body. The copper sheets 264 are electrically connected to the electric heating wire 263. It also includes two brushes 265. The positions of the brushes 265 correspond to the copper sheets 264 at both ends of the wheel body. When the wheel body is installed on the base, the brushes 265 are in contact with the copper sheets 264. The brushes 265 are electrically connected to an external power source. During the rotation of the wheel body, the brushes 265 remain stationary, and the wheel body can rotate freely. The electric heating wire heats the wheel body, ensuring that the temperature difference between the cage heated by electromagnetic induction and the wheel body is reduced, thereby reducing thermal stress.

[0092] The specific usage steps are as follows:

[0093] At the start of processing, the active height limiting wheel 24 is first adjusted to the open position, with its axis parallel to that of the cage, creating conditions for subsequent cage placement. Next, the cage is placed within the clamping space formed by the inner and outer extrusion wheels, the active wheel 26, and the limiting wheel, with the bottom surface of the cage in contact with the bottom flat reference wheel 25. Subsequently, the inner and outer extrusion wheels, the active wheel 26, and the limiting wheel are moved to gradually bring them into close contact with the inner and outer wall contours of the cage, ensuring the cage remains stable within the clamping space and preparing for subsequent deformation processing. Then, the active height limiting wheel 24 is brought into contact with the upper surface of the cage, and the active wheel 26 is rotated to test rotational smoothness.

[0094] After initial placement and wheel contact are completed, the cage undergoes initial deformation. The outer compression wheel 20 and inner compression wheel 22 on one side are selected and moved synchronously towards the center of the cage, while the wheel on the other side remains in its current position. Under this action of compression on one side and fixation on the other, the cage experiences uneven compressive force, resulting in initial elliptical deformation.

[0095] After the cage forms its initial elliptical deformation, the rotation of the drive wheel 26 causes the cage to rotate as well, ensuring that all parts of the cage are evenly affected by subsequent processing. The heating function of each wheel is activated simultaneously. Heating can reduce the cage's yield strength.

[0096] After a certain period of rotation of the drive wheel 26 and heating of the wheel body, further deformation is performed. A single outer extrusion wheel 20 is selected and controlled to move in the direction of the two inner extrusion wheels 22. Under the extrusion action of the outer extrusion wheel 20, the shape of the cage will change, gradually forming an S-shaped deformation.

[0097] After the cage undergoes an S-shaped deformation for a certain period of time, the controller begins its intelligent adjustment function. Based on preset standard circle parameters, the controller precisely controls the position and speed of each wheel, enabling them to work together to gradually adjust the cage to the standard circle position. Once the cage reaches the standard circle position, the rolling operation begins.

[0098] For any parts not mentioned in this invention, existing technologies can be used or referenced.

[0099] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in the present invention, and these should all be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for removing residual stress in a cage, characterized in that, Includes the following steps: S1: Positioning and contour clamping: The round cage is precisely placed in the clamping space formed by multiple contouring rollers, and the contouring rollers match the contour of the cage; through the close fit between the contouring rollers and the inner and outer contours of the cage, the cage is stably clamped, and the cage can rotate smoothly as the contouring rollers rotate. S2: Elliptical Deformation: The contouring roller applies pressure to the cage, causing the cage to undergo elliptical deformation, increasing the roundness deviation; at the same time, it ensures that the cage can rotate normally under the drive of the contouring roller. S3: S-shaped stress relief: The conforming pressure roller drives the cage, which undergoes elliptical deformation, to rotate for a set time. During the elliptical rotation, the outer conforming pressure roller applies pressure towards the two inner conforming pressure rollers, or the inner conforming pressure roller applies pressure towards the two outer conforming pressure rollers, causing local deformation of the ellipse. As it rotates, the deformed part contacts the inner or outer conforming pressure rollers and recovers, forming an S-shaped deformation, achieving stress relief, stabilizing the elliptical shape, and promoting permanent plastic deformation of the cage, thereby initially improving the roundness of the cage. S4: Rounding: Adjust all the contour wheels in contact with the cage to the standard outer diameter of the cage product; rotate the cage again for the design time to allow it to undergo permanent plastic deformation in the new dimensional position; through this step, the roundness of the cage is finally made to meet the qualified standard.

2. The method for removing residual stress from a cage according to claim 1, characterized in that, In step S2, the contouring pressure roller can dynamically adjust its relative position with the cage. The contouring pressure roller moves precisely a preset design distance in the direction toward the center of the cage, applying controllable pressure to the cage and causing the cage to produce an elliptical deformation. The major axis dimension of the elliptical deformation is denoted as D2, the minor axis dimension is denoted as D1, and the standard outer circle dimension of the cage product is denoted as D3, and D1 < D3 < D2 is satisfied.

3. The method for removing residual stress from a cage according to claim 2, characterized in that, In step S2, the relative deformation ratio between the moving distance of the contouring roller and the diameter of the cage ranges from 0.7% to 2%.

4. The method for removing residual stress from a cage according to claim 2, characterized in that, In step S2, the contouring rollers that contact the outer and inner sides of the cage both move in the direction toward the center of the cage; the inner contouring roller moves at a slower speed toward the center than the outer contouring roller moves at a slower speed toward the center.

5. The method for removing residual stress from a cage according to claim 1, characterized in that, In steps S3 and S4, the cage is heated, and the cage is driven to rotate synchronously during the heating process.

6. The method for removing residual stress from a cage according to claim 1, characterized in that, It also includes the following steps, S5: Staged cooling process: After the cage deformation is completed in step S4, it is first naturally cooled to below 200°C, and then forced cooling is used to room temperature; S6: Vibration: While performing step S5, use a vibration aging treatment cage with a vibration frequency of 50-200Hz.

7. The apparatus used in the method for removing residual stress from a cage according to any one of claims 1-6, characterized in that, It includes a limiting wheel for limiting the product, a driving wheel that can drive the product to rotate, an extrusion wheel that can adjust the roundness of the product opening, a driving height limiting wheel that abuts against the upper surface of the cage, and a bottom flat reference wheel that abuts against the lower surface of the cage; the outer contour shape of the extrusion wheel, the driving wheel, and the limiting wheel is adapted to the outer wall shape of the cage. The extrusion wheel, the drive wheel, and the limit wheel each include two sets of wheels, one inner and one outer. The extrusion wheel, drive wheel, and limit wheel are all movably mounted on the adjustment base; The cage is positioned in the clamping space formed between the inner and outer extrusion wheels, the drive wheel, and the limit wheel, and the extrusion wheels, drive wheel, and limit wheel are in contact with the inner and outer wall contours of the cage.

8. The apparatus for removing residual stress from a cage according to claim 7, characterized in that, With the center of the cage as the center, the longitudinal axis and the transverse axis are set. The extrusion wheel and the limiting wheel are symmetrically distributed relative to the longitudinal axis. No wheel body is set at the straight position of the longitudinal axis. The driving wheel is symmetrically distributed relative to the transverse axis or the extrusion wheel and the limiting wheel are connected to drive the active rotation.

9. The apparatus for removing residual stress from a cage according to claim 8, characterized in that, The inner and outer wheel bodies are spaced apart.

10. The apparatus for removing residual stress from a cage according to claim 7, characterized in that, The base is adjusted to accommodate an inductor coil, and the cage is placed inside the inductor coil area to achieve electromagnetic induction heating of the cage / extrusion wheel, limit wheel, or drive wheel. The wheel body contains a heating wire, and copper plates are located at both ends of the wheel body, electrically connected to the heating wire. Two brushes are also included, their positions corresponding to the copper plates at both ends of the wheel body. When the wheel body is mounted on the base, the brushes contact the copper plates. The brushes are electrically connected to an external power source. During wheel rotation, the brushes remain stationary, while the wheel body can rotate freely.

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