A cooperative positioning anti-vibration device for cold drawing of stainless steel pipe

Abstract

The present application relates to the technical field of metal pipe cold working, and particularly relates to a cooperative positioning anti-vibration device for stainless steel pipe cold drawing, which comprises a rack, a drawing die, a positioning seat, a guide rail, a moving seat, a driving device, a follow-up assembly and a controller. The follow-up assembly comprises a connecting frame provided with at least three rollers, and at least one roller is connected with a radial pre-tightening assembly provided with a pressure sensor. The drawing die is provided with a tapered positioning sleeve on one side, and the positioning hole of the tapered positioning sleeve comprises a tapered guide section and a cylindrical centering section in sequence. The controller controls the moving seat to move along with the steel pipe to be drawn according to the position sensor signal, and gradually adjusts the pre-tightening force of the roller from the first pre-tightening force to the second pre-tightening force in the process that the front end of the steel pipe to be drawn enters the cylindrical centering section from the tapered guide section, while keeping the rolling contact between the roller and the steel pipe to be drawn. The device realizes the cooperative positioning and vibration suppression of the steel pipe in the whole drawing stroke.

Description

Technical Field

[0001] This invention relates to the technical field of cold working of metal pipes, and specifically to a collaborative positioning anti-vibration device for cold drawing of stainless steel pipes. Background Technology

[0002] During the cold drawing process of stainless steel pipes, the steel pipe undergoes plastic deformation under the traction of the drawing die. Its straightness, surface quality, and dimensional accuracy largely depend on the stability during the drawing process. With the increasingly widespread application of high-precision stainless steel pipes in aerospace, petrochemical, and medical device fields, higher requirements are placed on the concentricity and surface quality of the cold-drawn finished pipes. Therefore, the positioning and anti-vibration control of the steel pipe during the cold drawing process have become key aspects that need improvement.

[0003] For example, Chinese invention patent CN100408214C discloses a diameter expansion device for a hydraulic cold drawing machine. This device includes a tube-holding mechanism on the machine body, comprising a tube-holding cylinder, a sliding plate, and tube-holding rollers located on both sides of the tube blank. The tube-holding cylinders push the rollers to clamp the outer diameter of the tube blank, and the rollers retract as the tube diameter increases during diameter expansion. This design utilizes rollers to provide support and clamping for the tube blank, reducing tube blank instability during diameter expansion. Furthermore, by incorporating multiple tube-holding mechanisms, straightness can be improved when drawing longer tubes.

[0004] However, the tube-holding mechanism of CN100408214C is fixed to the cold drawing machine body, and the position of the rollers does not move synchronously with the weak overhang area of ​​the steel pipe to be drawn. The retraction of the rollers is mainly passively triggered by the reaction force generated by the expansion of the pipe diameter. This solution does not involve the coordinated adjustment of the support position and preload according to the position of the steel pipe, the vibration state or the actual radial force, nor does it solve the problem of smooth handover of the external roller support to the mold centering when the front end of the steel pipe enters the mold.

[0005] For example, Chinese utility model patent CN202316603U discloses a cold-drawing inner mold adjustment and positioning device for seamless steel pipes with internal threads. It features a moving trolley mounted on a parallel guide rail, on which a mandrel and an inner mold, coaxial with the inner hole of the outer mold, are installed. An adjuster is placed between the moving trolley and the drawing seat to adjust the axial position of the inner and outer molds. This solution facilitates coaxial positioning and position adjustment between the mandrel, inner mold, and outer mold.

[0006] However, the mobile trolley of CN202316603U is mainly used to carry and adjust the mandrel and inner mold. It does not set a circumferential rolling support structure for the middle and rear section of the steel pipe to be pulled, nor does it disclose that it can follow up and track the position of the steel pipe to be pulled, adjust the radial preload according to the pressure and vibration information, or achieve continuous positioning by reducing the preload between the guide centering structure and the roller support during the process of the steel pipe entering the mold.

[0007] Therefore, existing technologies still require a collaborative positioning anti-vibration device for cold drawing: one that can provide follow-up radial rolling support for the middle and rear sections of the steel pipe throughout the entire cold drawing stroke and suppress vibration and sway, and also smoothly transfer the external support to the centering structure coaxial with the die during the transition stage when the front end of the steel pipe enters the drawing die, thereby reducing the impact of support switching and improving the straightness, concentricity and surface quality of the finished pipe. Summary of the Invention

[0008] The main objective of this application is to provide a collaborative positioning anti-vibration device for cold drawing of stainless steel pipes, which solves the technical problems of existing cold drawing equipment, such as the lack of follow-up support in the middle and rear sections of the steel pipe, which causes lateral vibration and bending swaying of the steel pipe during the drawing process, and the lack of guidance and centering when the front end of the steel pipe enters the mold, which causes skew and shaking in the initial stage. It has the beneficial effects of achieving collaborative positioning anti-vibration throughout the entire stroke of cold drawing of steel pipes and improving the straightness and surface quality of finished pipes.

[0009] To achieve the above objectives, the present invention provides a cooperative positioning anti-vibration device for cold drawing stainless steel pipes, comprising a frame, a drawing die at one end of the frame, a mandrel passing through the steel pipe to be drawn, a positioning seat for positioning the tail end of the mandrel at the other end of the frame, a guide rail extending along the drawing direction on the frame, a movable seat slidably mounted on the guide rail, a driving device for driving the movable seat to move along the guide rail on the frame, and a follower assembly at its top, wherein the follower assembly includes a connecting frame, at least three rollers distributed around the steel pipe to be drawn on the connecting frame, at least one of the rollers being connected to a radial preload assembly, and a pressure sensor being provided on the radial preload assembly; the drawing... A tapered positioning sleeve is provided on the side of the mold facing the positioning seat. The positioning hole of the tapered positioning sleeve forms a tapered guide section and a cylindrical centering section in sequence along the direction close to the drawing die. The cylindrical centering section is coaxial with the working hole of the drawing die. The frame is also provided with a position sensor and a controller. The controller is connected to the position sensor, the drive device, the radial preload assembly and the pressure sensor respectively. It is used to control the moving seat to move with the steel pipe to be drawn. During the process of the front end of the steel pipe to be drawn entering the cylindrical centering section from the tapered guide section, the preload of the roller is gradually adjusted from the first preload to a second preload that is less than the first preload, while maintaining the roller in rolling contact with the steel pipe to be drawn.

[0010] As a preferred embodiment, the positioning seat includes a base, the base having a limiting cavity for accommodating positioning balls, and the tail end of the mandrel abutting against one side of the positioning balls.

[0011] Furthermore, the base is provided with a first adjusting screw, a second adjusting screw, and a third adjusting screw that abut against the positioning ball. The first adjusting screw is arranged along the axial direction of the mandrel, and the second adjusting screw and the third adjusting screw are arranged along two mutually perpendicular radial directions.

[0012] Furthermore, the end faces of the mandrel, the first adjusting screw, the second adjusting screw, and the third adjusting screw that contact the positioning ball are all curved surfaces adapted to the spherical surface of the positioning ball.

[0013] Furthermore, the positioning ball can rotate within the limiting cavity, the first adjusting screw is used to adjust the axial preload of the mandrel tail end, and the second and third adjusting screws are used to adjust the vertical and lateral positions of the mandrel tail end, respectively.

[0014] As a preferred embodiment, the drive device includes a servo motor mounted on the frame, the output end of the servo motor is connected to a transmission screw extending along the guide rail, and the movable seat is provided with a screw nut that is threadedly engaged with the transmission screw.

[0015] Furthermore, the position sensor includes a first position sensor for detecting the position of the tail end of the steel pipe to be pulled, and a second position sensor disposed at the inlet of the tapered positioning sleeve for detecting the position of the front end of the steel pipe to be pulled.

[0016] Furthermore, the controller controls the movement of the moving seat according to the real-time position of the tail end of the steel pipe to be pulled, so that the axial distance between the roller and the tail end of the steel pipe to be pulled is kept within a preset distance range.

[0017] As a preferred embodiment, the connecting frame is provided with three rollers, which are distributed at equal angles along the circumference of the steel pipe to be pulled. Two of the rollers are located below the steel pipe to be pulled and form a supporting part, while the other roller is located above the steel pipe to be pulled and forms a pressing part.

[0018] Furthermore, each of the rollers has a concave arc-shaped working surface adapted to the outer periphery of the steel pipe to be pulled, and the concave arc-shaped working surface is provided with an elastic wear-resistant layer.

[0019] As a preferred embodiment, a swing arm is rotatably mounted on the connecting frame, and the roller located above the steel pipe to be pulled is rotatably mounted on one end of the swing arm.

[0020] Furthermore, the radial preload assembly includes a loading drive mounted on the connecting frame, the output end of which is connected to an elastic preload member, which abuts against the other end of the swing arm to apply a radial preload force to the roller located above the steel pipe to be pulled through the swing arm.

[0021] Furthermore, the elastic preload is a disc spring assembly or a compression spring, and the pressure sensor is located between the loading drive and the swing arm.

[0022] As a preferred embodiment, the connecting frame is provided with a limiting member located on the swing path of the swing arm. The limiting member is used to limit the maximum distance that the roller located above the steel pipe to be pulled can move toward the steel pipe to be pulled.

[0023] Furthermore, the connecting frame or movable seat is equipped with a vibration sensor connected to the controller. The controller adjusts the output pressure of the loading drive component based on the radial force detected by the pressure sensor and the vibration amplitude detected by the vibration sensor.

[0024] As a preferred embodiment, the end of the tapered positioning sleeve away from the drawing die is provided with a flared capturing part, the flared capturing part is connected to the tapered guide section, and an arc transition section is provided between the tapered guide section and the cylindrical centering section.

[0025] Furthermore, the tapered positioning sleeve has a cylindrical positioning stop at one end near the drawing die, and the drawing die has a positioning groove that matches the cylindrical positioning stop. The tapered positioning sleeve is inserted into the positioning groove through the cylindrical positioning stop.

[0026] As a preferred embodiment, the controller is configured to: when the second position sensor does not detect the front end of the steel pipe to be pulled entering the tapered guide section, control the radial preload assembly to apply a first preload force to the roller; as the front end of the steel pipe to be pulled moves along the tapered guide section towards the cylindrical centering section, gradually reduce the output pressure of the radial preload assembly; after the front end of the steel pipe to be pulled enters the cylindrical centering section, control the radial preload assembly to apply a second preload force to the roller; the second preload force is less than the first preload force and not less than the minimum contact force required to maintain rolling contact between the roller and the steel pipe to be pulled, so that the radial support effect on the steel pipe to be pulled is continuously transferred from the roller to the cylindrical centering section.

[0027] The beneficial effects of this invention are as follows: (1) In this invention, a three-roller floating support mechanism that can synchronously track the steel pipe is used. The rollers are evenly arranged circumferentially to form a stable radial constraint. The controller controls the moving seat to follow the tail end of the steel pipe in real time, constraining the overhanging section of the steel pipe throughout the entire process. The rollers have an elastic wear-resistant layer that can absorb vibration. Combined with pressure and vibration sensors, the radial preload is adjusted in a closed loop, which effectively suppresses the lateral vibration and bending of the steel pipe during long-stroke cold drawing, improves the problems of uneven wall thickness and straightness deviation, avoids steel pipe bending and mold wear and scrapping, and stabilizes the surface processing quality of the pipe.

[0028] (2) In this invention, the front end of the mold is provided with a tapered positioning sleeve with a flared capture structure, which can correct the skewed front end of the steel pipe and center it coaxially. The controller adjusts the preload of the rollers in segments: a high preload is applied before the steel pipe enters the mold, the load is gradually reduced when the front end slides into the guide section, and a low preload is maintained after it has fully entered the cylindrical centering section. The support force is smoothly transferred from the rollers to the positioning sleeve, without constraint discontinuity or impact vibration throughout the process, which solves the problem of skewness in the early stage of the steel pipe entering the mold, continuously ensures the coaxial accuracy of the steel pipe, greatly improves the concentricity of the finished product, and the moving seat follows the steel pipe to be pulled through the position sensor and controller, and actively reduces the preload of the rollers when the steel pipe enters the cylindrical centering section from the tapered guide section, so that the roller support is smoothly transferred to the mold centering, thereby reducing the risk of support switching impact and steel pipe surface damage.

[0029] (3) In this invention, the mandrel tail end adopts a ball-type three-axis adjustable positioning seat. Three orthogonal lead screws cooperate with spherical contact balls to precisely adjust the three-dimensional position of the mandrel, release the skew stress, and achieve precise alignment between the mandrel and the mold, eliminating the wall thickness deviation caused by eccentricity. The device links the follow-up roller, the front centering sleeve, and the rear positioning seat, and relies on the unified coordinated control of the controller to achieve continuous and stable constraint of the entire stroke of cold drawing of steel pipe, improve the overall pipe size accuracy, adapt to the production of high-precision stainless steel pipe, reduce the scrap rate, and extend the service life of the mold. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structural distribution of the collaborative positioning and anti-vibration device for cold drawing of stainless steel pipes in this invention; Figure 2 This is a schematic diagram of the main structure of the movable seat in this invention; Figure 3 This is a cross-sectional view of the radial preload assembly in this invention. Figure 4 This is a cross-sectional view of the tapered positioning sleeve in this invention. Figure 5 This is a cross-sectional view of the positioning seat in this invention; Figure 6 This is the control and sensing logic diagram of the collaborative positioning anti-vibration device for cold drawing of stainless steel pipes in this invention.

[0031] Reference numerals: 1. Frame; 10. Guide rail; 110. Servo motor; 2. Drawing die; 3. Mandrel; 4. Positioning seat; 40. Positioning ball; 41. First adjusting screw; 42. Second adjusting screw; 400. Base; 401. Limiting cavity; 5. Moving seat; 50. Connecting frame; 51. Roller; 52. Radial preload assembly; 53. Swing arm; 520. Loading drive component; 521. Elastic preload component; 522. Limiting component; 6. Gradient positioning sleeve; 60. Gradient guide section; 61. Cylindrical centering section; 62. Cylindrical positioning stop; 600. Flared capture part; 601. Arc transition section. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0033] It should be noted that the "front end", "rear end" or "tail end" described in the embodiments of this application are relative to the drawing direction. During the drawing process, the end of the steel pipe to be drawn that moves toward the drawing die 2 is called the front end, and the other end that moves away from the drawing die 2 is called the tail end.

[0034] like Figures 1 to 6 As shown in the figure, this application provides a cooperative positioning anti-vibration device for cold drawing stainless steel pipes. The device includes a frame 1, a drawing die 2 is fixedly installed at one end of the frame 1, a mandrel 3 is inserted inside the steel pipe to be drawn, and a positioning seat 4 for positioning the tail end of the mandrel 3 is provided at the other end of the frame 1. A guide rail 10 extending along the drawing direction is fixedly installed on the frame 1, and a movable seat 5 is slidably installed on the guide rail 10. A drive device is provided on the frame 1 to drive the movable seat 5 to move along the guide rail 10, and a follower component is provided on the top of the movable seat 5.

[0035] Specifically, the follower component includes a connecting frame 50, on which at least three rollers 51 are arranged around the steel pipe to be pulled. At least one roller 51 is connected to a radial preload component 52, and a pressure sensor is arranged on the radial preload component 52.

[0036] A tapered positioning sleeve 6 is provided on the side of the drawing die 2 facing the positioning seat 4. The positioning hole of the tapered positioning sleeve 6 forms a tapered guide section 60 and a cylindrical centering section 61 in sequence along the direction close to the drawing die 2.

[0037] The axis of the cylindrical centering section 61 coincides with the axis of the working hole of the drawing die 2 to ensure centering accuracy.

[0038] The frame 1 is also equipped with a position sensor and a controller. The controller is electrically connected to the position sensor, the drive unit, the radial preload assembly 52, and the pressure sensor, respectively.

[0039] The controller is configured to control the moving seat 5 to move synchronously with the steel pipe to be pulled, and during the process of the front end of the steel pipe to be pulled entering the cylindrical centering section 61 from the tapered guide section 60, gradually adjust the preload applied by the roller 51 to the steel pipe to be pulled from the first preload to the second preload which is less than the first preload, while always maintaining the rolling contact between the roller 51 and the steel pipe to be pulled.

[0040] According to this embodiment, the collaborative positioning anti-vibration device solves the lateral vibration problem during the long overhang drawing process by providing circumferentially distributed rollers 51 with dynamically adjustable preload in the middle and rear sections of the steel pipe to be drawn. Simultaneously, by setting a positioning sleeve with both tapering guidance and cylindrical centering functions at the entrance of the drawing die 2, and coordinating the smooth reduction of the preload of the rollers 51 during the transition phase when the steel pipe enters the die, it ensures that the steel pipe is always subjected to reasonable and uninterrupted physical constraints throughout the entire drawing process, reducing swaying, vibration, and bending deformation caused by lack of support or switching impacts, thereby improving the straightness, wall thickness uniformity, and surface quality of the finished pipe.

[0041] In practical applications, the overall working process of this collaborative positioning anti-shake device is as follows: In the initial stage, the steel pipe to be pulled is fitted onto the mandrel 3, and the tail end of the mandrel 3 is precisely fixed by the positioning seat 4. At this time, the controller controls the drive device to move the moving seat 5 to the initial position close to the tail end of the steel pipe to be pulled, and controls the radial pre-tightening component 52 to press the roller 51 against the outer circumference of the steel pipe with a larger (relative to the second pre-tightening force) first pre-tightening force, forming a strong radial support.

[0042] After the drawing process begins, the steel pipe passes through the front end of the follower assembly and first contacts the drawing die 2. During this process, the first position sensor detects the position of the tail end of the steel pipe in real time. Based on this position signal, the controller controls the servo motor 110 to drive the moving seat 5 to move synchronously and in the same direction as the steel pipe along the guide rail 10, so that the axial distance between the roller 51 and the tail end of the steel pipe is kept within a preset distance, ensuring the most effective vibration suppression for the overhang section.

[0043] Simultaneously, when the second position sensor detects that the front end of the steel pipe has entered the tapered guide section 60 of the tapered positioning sleeve 6, the controller immediately initiates control. During the brief period when the front end of the steel pipe is guided by the tapered guide section 60 and moves into the cylindrical centering section 61, the preload of the roller 51 is smoothly reduced from the first preload to the second preload. At this point, the front end of the steel pipe is precisely coaxially constrained by the cylindrical centering section 61, while the middle and rear sections of the steel pipe are still supported by the roller 51 rolling with a smaller preload, achieving a smooth transfer of support. Thus, both ends of the steel pipe are in a stable constrained state throughout the stroke until the drawing is completed.

[0044] In one embodiment, such as Figure 5As shown, the positioning seat 4 includes a base 400, inside which a limiting cavity 401 is machined for accommodating the positioning ball 40. The tail end of the mandrel 3 abuts against one side of the positioning ball 40. A first adjusting screw 41, a second adjusting screw 42, and a third adjusting screw are mounted on the base 400, all abutting against the positioning ball 40. The first adjusting screw 41 is arranged along the axial direction of the mandrel 3 and is used to axially tighten the positioning ball 40, thereby adjusting the axial preload at the tail end of the mandrel 3. The second adjusting screw 42 and the third adjusting screw are arranged along two mutually perpendicular radial directions (e.g., horizontal and vertical). By rotating these three mutually orthogonal screws, the positioning ball 40 can be driven to produce a small three-dimensional spatial displacement within the limiting cavity 401, thereby precisely adjusting the position of the tail end of the mandrel 3 in the upper, lower, left, right, and axial directions. This achieves precise alignment adjustment between the mandrel 3 and the working hole of the drawing die 2, effectively preventing uneven wall thickness of the steel pipe caused by the eccentricity of the mandrel 3.

[0045] Specifically, the end faces of the mandrel 3, the first adjusting screw 41, the second adjusting screw 42, and the third adjusting screw that contact the positioning ball 40 are all machined into concave spherical or conical surfaces that fit the spherical surface of the positioning ball 40. This curved surface fit design ensures that the adjusting force is always transmitted along the normal direction of the positioning ball 40, the contact stress is evenly distributed, and crushing caused by point contact and creeping phenomenon during the adjustment process are avoided. At the same time, the positioning ball 40 is allowed to rotate within the limiting cavity 401. During the drawing process, when the tail end of the mandrel 3 has a slight tendency to deflect due to force, the positioning ball 40 can adaptively adjust its force posture through its own slight rotation, absorb and release the deflection stress, thereby preventing the tail end of the mandrel 3 from generating additional bending moment due to rigid constraint and ensuring the stability of the working posture of the mandrel 3.

[0046] In one embodiment, such as Figure 1 As shown, the drive unit specifically includes a servo motor 110 mounted on the frame 1. The output end of the servo motor 110 is connected to a transmission screw extending along the guide rail 10 via a coupling. A screw nut that is threadedly engaged with the transmission screw is fixedly installed at the bottom of the movable seat 5. The controller precisely controls the speed and angle of the servo motor 110 through pulse or bus commands, thereby realizing the control of the position and speed of the movable seat 5.

[0047] Specifically, the position sensors include a first position sensor for detecting the real-time position of the tail end of the steel pipe to be pulled, and a second position sensor located at the inlet of the tapered positioning sleeve 6 for detecting whether the front end of the steel pipe to be pulled has arrived. Based on the tail end position information fed back by the first position sensor, the controller calculates the required tracking speed of the moving seat 5 in real time and controls the servo motor 110 to drive the moving seat 5 to move, ensuring that the axial distance between the roller 51 and the tail end of the steel pipe to be pulled is always maintained within a preset range, typically 10-50mm. This ensures that throughout the entire drawing process, the roller 51 always provides support for the weakest area of ​​the steel pipe with the longest overhang.

[0048] In one embodiment, such as Figure 1 and Figure 2 As shown, the connecting frame 50 is equipped with three rollers 51, which are distributed at 120° equidistant angles along the circumference of the steel pipe to be pulled. Two of the rollers 51 are located below the steel pipe, and their wheel surfaces together form a V-shaped support to bear the weight of the steel pipe; the other roller 51 is located directly above the steel pipe, forming a pressing part that applies a downward preload to the steel pipe. This three-point layout, with two points supporting from below and one point pressing from above, constitutes a stable clamping triangle, which can apply uniform constraint to the steel pipe in all radial directions in a plane perpendicular to the steel pipe axis, providing good support rigidity and a simple structure.

[0049] Specifically, such as Figure 6 As shown, each roller 51 has a concave arc-shaped working surface that matches the outer circumference of the steel pipe to be drawn. The radius of curvature of this arc-shaped surface is slightly larger than the outer diameter of the steel pipe, so that the roller 51 and the steel pipe form a surface contact rather than a line contact, increasing the contact area and effectively reducing the contact stress. An elastic wear-resistant layer, such as a polyurethane layer or a wear-resistant rubber layer, is vulcanized or embedded on the concave arc-shaped working surface. This elastic wear-resistant layer not only protects the surface of the steel pipe from scratches by the roller 51, but also absorbs high-frequency micro-amplitude vibrations during the drawing process through its own slight elastic deformation, thus playing a damping and vibration reduction role.

[0050] In one embodiment, such as Figure 1 , Figure 2 and Figure 3As shown, a swing arm 53 is rotatably mounted on the connecting frame 50 via a rotating shaft, and a roller 51 located above the steel pipe to be pulled is rotatably mounted on one end of the swing arm 53. The radial preload assembly 52 specifically includes a loading drive 520 mounted on the connecting frame 50. The loading drive 520 can be an electrically controlled pneumatic cylinder, hydraulic cylinder, or electric cylinder, and its cylinder body is fixed on the connecting frame 50. The output end of the loading drive 520 is connected to an elastic preload member 521, and the other end of the elastic preload member 521 abuts against the other end of the swing arm 53. When the output end of the loading drive 520 extends, it pushes the elastic preload member 521 against the swing arm 53, causing the swing arm 53 to swing around the rotating shaft, thereby driving the roller 51 at its other end to press down and apply radial preload force to the steel pipe to be pulled.

[0051] Specifically, the elastic preload element 521 is either a disc spring assembly or a compression spring. Disc spring assemblies offer the stiffness characteristic of providing large loads under small deformations and have a long lifespan, making them suitable for compact structures; compression springs, on the other hand, have linear stiffness, facilitating force calculation and control. A pressure sensor is positioned on the force transmission path between the output end of the loading drive element 520 and the swing arm 53. Specifically, it can be a washer-type or piezoelectric force sensor, clamped between the elastic preload element 521 and the swing arm 53, used to directly and accurately measure the actual force applied to the swing arm 53. This force is proportional to the preload force of the roller 51 on the steel pipe. This design integrates loading, force measurement, and elastic buffering functions, achieving precise closed-loop control of the preload force.

[0052] More specifically, a limiting member 522 is also fixedly installed on the connecting frame 50, located on the swing path of the swing arm 53. This limiting member 522 is a solid, one-piece stop; when the swing arm 53 swings to its limit position, its power arm end will touch and stop on the limiting member 522. This limiting member 522 is used to physically limit the maximum distance the upper roller 51 moves towards the steel pipe to be pulled, preventing excessive downward pressure from the roller 51 due to misoperation or control system failure, thus protecting the steel pipe from being flattened or indented.

[0053] In addition, a vibration sensor connected to the controller is installed on the connecting frame 50 or the movable seat 5. The vibration sensor is used to monitor the vibration amplitude of the follower component during the drawing process in real time. The controller combines the radial force detected by the pressure sensor and the vibration amplitude detected by the vibration sensor. When the vibration amplitude exceeds a preset threshold, it indicates that the current support force is insufficient to suppress the vibration, and the controller will control the loading drive 520 to appropriately increase the output pressure; when the vibration amplitude is very low and the pressure monitoring value is stable, the controller can appropriately reduce the output pressure to reduce the rolling friction resistance of the roller 51 on the steel pipe, thereby achieving dynamic optimization of the preload force based on the actual working conditions.

[0054] In one embodiment, such as Figure 4As shown, the end of the tapered positioning sleeve 6 furthest from the drawing die 2 is provided with a flared capturing part 600. This flared capturing part 600 is a conical or trumpet-shaped opening, the maximum inner diameter of which is much larger than the outer diameter of the steel pipe to be drawn. The rear end of the flared capturing part 600 is smoothly connected to the tapered guide section 60. Even if the front end of the steel pipe undergoes a slight deflection due to its long journey, it can be smoothly received by the large diameter of the flared capturing part 600 and guided into the tapered guide section 60, thereby reducing the risk of rigid collision between the steel pipe and the end face of the tapered positioning sleeve 6.

[0055] Specifically, the tapered guide section 60 and the cylindrical centering section 61 are smoothly connected by an arc transition section 601, so that the contact trajectory of the front end of the steel pipe is smooth and without inflection points during the process of sliding from the inclined plane to the cylindrical surface.

[0056] More specifically, the outer surface of the tapered positioning sleeve 6 near the drawing die 2 is machined with a precision cylindrical positioning stop 62. Correspondingly, a positioning groove with a transition or clearance fit to the cylindrical positioning stop 62 is formed on the end face of the drawing die 2. The tapered positioning sleeve 6 is inserted into the positioning groove through the cylindrical positioning stop 62 and is axially pressed by fasteners such as screws. This positioning method of cylindrical surface to cylindrical surface fit, utilizing its own automatic centering function, ensures the coaxial installation accuracy between the tapered positioning sleeve 6 and the drawing die 2, thereby fundamentally ensuring that the cylindrical centering section 61 and the axis of the working hole are precisely coincident.

[0057] In one embodiment, the controller is configured to execute the following phased preload control logic: During the initial and middle stages of the drawing process, the second position sensor has not yet detected the front end of the steel pipe to be drawn entering the tapered guide section 60. At this time, the controller controls the loading drive 520 of the radial preload assembly 52 to output full pressure, applying a large first preload force to the roller 51 to strongly constrain the middle and rear sections of the steel pipe and provide maximum vibration resistance.

[0058] As the drawing stroke nears its end, the second position sensor detects that the front end of the steel pipe to be drawn has entered the tapered guide section 60. The controller then executes a preset gradual decreasing curve based on the displacement of the steel pipe's front end in the feed direction (this displacement can be obtained from the drawing trolley's encoder or calculated based on speed and time), controlling the loading drive 520 to gradually reduce its output pressure. During this process, the front end of the steel pipe is gradually corrected and retracted under the guidance of the conical surface of the tapered guide section 60, and its dependence on the radial support of the roller 51 gradually decreases.

[0059] Once the front end of the steel pipe reaches the cylindrical centering section 61, the controller stabilizes the output pressure of the loading drive component 520 at a lower value, thereby applying a small second preload to the roller 51. This second preload is calibrated to be slightly higher than the minimum contact force required to maintain reliable rolling contact between the roller 51 and the steel pipe, for example, slightly greater than the force required to overcome the weight of the servo component and the rotational inertia of the roller 51. At this point, the front end of the steel pipe is completely constrained by the cylindrical centering section 61, and the radial positioning task is taken over by the cylindrical centering section 61. The function of the roller 51 changes from primary support to auxiliary servo alignment. Through this strictly controlled, continuously decreasing preload adjustment, the radial support force on the steel pipe is smoothly and uninterruptedly transferred from the roller 51 to the cylindrical centering section 61, avoiding any sudden changes in support force or control vacuum periods.

[0060] Furthermore, it should be noted that in some optional embodiments, the aforementioned drive device, in addition to employing a servo motor 110 in conjunction with a transmission lead screw, can also use a linear motor to directly drive the moving base 5, or use a servo motor 110 to drive a gear that meshes with a rack fixed on the frame 1. The power source for the loading drive component 520 can be pneumatic, hydraulic, or a voice coil motor or other fast-response solution. The material of the elastic wear-resistant layer can be selected from polyurethane or engineering plastics of different hardness depending on the working conditions. The specific shape of the flared capturing part 600 can be conical or an arc surface with a large radius of curvature. Those skilled in the art can select these alternative solutions according to actual production needs, and all of them should be covered within the scope of protection of this application.

[0061] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A collaborative positioning anti-vibration device for cold drawing of stainless steel pipes, comprising a frame (1), a drawing die (2) provided at one end of the frame (1), a mandrel (3) inserted into the steel pipe to be drawn, and a positioning seat (4) for positioning the tail end of the mandrel (3) at the other end of the frame (1), characterized in that: The frame (1) is provided with a guide rail (10) extending along the pulling direction. A movable seat (5) is slidably mounted on the guide rail (10). The frame (1) is provided with a driving device that drives the movable seat (5) to move along the guide rail (10). A follower assembly is provided on its top. The follower assembly includes a connecting frame (50). The connecting frame (50) is provided with at least three rollers (51) distributed around the steel pipe to be pulled. At least one of the rollers (51) is connected to a radial preload assembly (52). A pressure sensor is provided on the radial preload assembly (52). The drawing die (2) is provided with a tapered positioning sleeve (6) on the side facing the positioning seat (4). The positioning hole of the tapered positioning sleeve (6) is formed in sequence with a tapered guide section (60) and a cylindrical centering section (61) along the direction close to the drawing die (2). The cylindrical centering section (61) is coaxial with the working hole of the drawing die (2). The frame (1) is also equipped with a position sensor and a controller. The controller is connected to the position sensor, the drive device, the radial preload assembly (52) and the pressure sensor respectively. It is used to control the moving seat (5) to move with the steel pipe to be pulled. During the process of the front end of the steel pipe to be pulled entering the cylindrical centering section (61) from the tapered guide section (60), the preload of the roller (51) is gradually adjusted from the first preload to the second preload which is less than the first preload, while maintaining the roller (51) in rolling contact with the steel pipe to be pulled.

2. The collaborative positioning anti-vibration device for cold drawing of stainless steel pipes according to claim 1, characterized in that: The positioning seat (4) includes a base (400), and the base (400) has a limiting cavity (401) for accommodating the positioning ball (40). The tail end of the mandrel (3) abuts against one side of the positioning ball (40). The base (400) is provided with a first adjusting screw (41), a second adjusting screw (42) and a third adjusting screw that abut against the positioning ball (40). The first adjusting screw (41) is arranged along the axial direction of the mandrel (3), and the second adjusting screw (42) and the third adjusting screw are arranged along two mutually perpendicular radial directions.

3. The collaborative positioning anti-vibration device for cold drawing of stainless steel pipes according to claim 2, characterized in that: The end faces of the mandrel (3), the first adjusting screw (41), the second adjusting screw (42) and the third adjusting screw that contact the positioning ball (40) are all curved surfaces that are adapted to the spherical surface of the positioning ball (40); The positioning ball (40) can rotate within the limiting cavity (401). The first adjusting screw (41) is used to adjust the axial preload of the tail end of the mandrel (3). The second adjusting screw (42) and the third adjusting screw are used to adjust the vertical and horizontal positions of the tail end of the mandrel (3) respectively.

4. The collaborative positioning anti-vibration device for cold drawing of stainless steel pipes according to claim 1, characterized in that: The drive device includes a servo motor (110) mounted on the frame (1), the output end of the servo motor (110) is connected to a transmission screw extending along the guide rail (10), and the moving seat (5) is provided with a screw nut that is threadedly engaged with the transmission screw. The position sensor includes a first position sensor for detecting the position of the tail end of the steel pipe to be pulled, and a second position sensor located at the inlet of the tapered positioning sleeve (6) for detecting the position of the front end of the steel pipe to be pulled. The controller controls the movement of the moving seat (5) according to the real-time position of the tail end of the steel pipe to be pulled, so that the axial distance between the roller (51) and the tail end of the steel pipe to be pulled is kept within a preset distance range.

5. The collaborative positioning anti-vibration device for cold drawing of stainless steel pipes according to claim 1, characterized in that: The connecting frame (50) is provided with three rollers (51). The three rollers (51) are distributed at equal angles along the circumference of the steel pipe to be pulled. Two of the rollers (51) are located below the steel pipe to be pulled and form a supporting part, while the other roller (51) is located above the steel pipe to be pulled and forms a pressing part. Each of the rollers (51) has a concave arc-shaped working surface adapted to the outer periphery of the steel pipe to be pulled, and the concave arc-shaped working surface is provided with an elastic wear-resistant layer.

6. The collaborative positioning anti-vibration device for cold drawing of stainless steel pipes according to claim 1, characterized in that: A swing arm (53) is rotatably mounted on the connecting frame (50), and the roller (51) located above the steel pipe to be pulled is rotatably mounted on one end of the swing arm (53). The radial preload assembly (52) includes a loading drive (520) mounted on the connecting frame (50), the output end of which is connected to an elastic preload member (521), which abuts against the other end of the swing arm (53) to apply radial preload force to the roller (51) located above the steel pipe to be pulled through the swing arm (53).

7. A cooperative positioning anti-vibration device for cold drawing of stainless steel pipes according to claim 6, characterized in that, The elastic preload (521) is a disc spring assembly or a compression spring, and the pressure sensor is located between the loading drive (520) and the swing arm (53).

8. A cooperative positioning anti-vibration device for cold drawing of stainless steel pipes according to claim 7, characterized in that: The connecting frame (50) is provided with a limiting member (522) located on the swing path of the swing arm (53). The limiting member (522) is used to limit the maximum distance that the roller (51) located above the steel pipe to be pulled moves toward the steel pipe to be pulled. The connecting frame (50) or the movable seat (5) is provided with a vibration sensor connected to the controller. The controller adjusts the output pressure of the loading drive (520) according to the radial force detected by the pressure sensor and the vibration amplitude detected by the vibration sensor.

9. A cooperative positioning anti-vibration device for cold drawing of stainless steel pipes according to claim 7, characterized in that: The tapered positioning sleeve (6) is provided with a flared capturing part (600) at one end away from the drawing die (2). The flared capturing part (600) is connected to the tapered guide section (60). An arc transition section (601) is provided between the tapered guide section (60) and the cylindrical centering section (61). The tapered positioning sleeve (6) has a cylindrical positioning stop (62) at one end near the drawing die (2). The drawing die (2) has a positioning groove that matches the cylindrical positioning stop (62). The tapered positioning sleeve (6) is inserted into the positioning groove through the cylindrical positioning stop (62).

10. A cooperative positioning anti-vibration device for cold drawing of stainless steel pipes according to claim 5, characterized in that: The controller is configured to: When the second position sensor does not detect the front end of the steel pipe to be pulled entering the tapered guide section (60), the radial preload assembly (52) is controlled to apply a first preload force to the roller (51); As the front end of the steel pipe to be pulled moves along the tapered guide section (60) toward the cylindrical centering section (61), the output pressure of the radial preload assembly (52) is gradually reduced. After the front end of the steel pipe to be pulled enters the cylindrical centering section (61), the radial pre-tightening assembly (52) is controlled to apply a second pre-tightening force to the roller (51); The second preload is less than the first preload and not less than the minimum contact force required to keep the roller (51) in rolling contact with the steel pipe to be pulled, so that the radial support effect on the steel pipe to be pulled is continuously transferred from the roller (51) to the cylindrical centering section (61).

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