An automobile part clamping device based on ring welding processing and a process thereof

Abstract

This invention relates to a clamping device and process for automotive parts based on circumferential welding. It includes an integral base, a first movable seat and a second movable seat respectively installed at both ends along the length of the integral base. Drive components are installed at both ends of the inner side of the integral base along the length direction. The output ends of the two drive components are connected to the first movable seat and the second movable seat respectively, for driving the first and second movable seats to move towards or away from each other and adjusting the distance between them. This invention uses an outer guide roller to position the thin-walled cylindrical part, while the inner side is contacted by an inner support seat, forming an outer guide and inner support structure. Simultaneously, the outer guide roller and the inner support seat clamp the tube wall and form a bidirectional constraint. This symmetrical force structure avoids the elliptical deformation caused by single-point radial extrusion of traditional three-jaw chucks, ensuring the geometric integrity of the thin-walled cylindrical part in the initial clamping stage, avoiding local stress concentration, and improving the roundness and concentricity of the weld.

Description

Technical Field

[0001] This invention relates to the field of automotive parts clamping technology, specifically to an automotive parts clamping device and process based on circumferential welding. Background Technology

[0002] In the automotive manufacturing industry, circumferential welding is a key process for connecting thin-walled cylindrical parts. It is widely used in the production of exhaust pipe assemblies, muffler housings, drive shaft sleeves, and various fluid transport pipelines. These automotive parts typically have long axial dimensions and thin walls. Their assembly accuracy directly determines the sealing performance, NVH (noise, vibration, and harshness) performance, and structural strength of the entire vehicle system. To ensure the quality of the circumferential weld, a special clamping device must be used to fix the parts to be welded in a preset position and maintain their positional stability and concentricity during the welding process. Therefore, the clamping device is not only the basic carrier for realizing automated welding, but also the core tooling to ensure the final forming quality of automotive parts. However, when clamping thin-walled cylindrical automotive parts, traditional three-jaw chucks or multi-point rigid clamps often apply large radial pressure to fix the parts during clamping. Concentrated loads can easily cause elliptical deformation or local indentation in the thin-walled tube, destroying the original geometry of the parts and affecting the alignment of subsequent welding. Secondly, due to the poor rigidity of thin-walled parts, when the length-to-diameter ratio is large, it is difficult to resist the bending deformation caused by its own weight and welding thermal stress by supporting only the two ends, resulting in misalignment or collapse during welding. Furthermore, whether it is an internal support or external clamping structure, for complex tubes with internal reinforcing ribs, constrictions, or irregular cross-sections, traditional mechanical internal support structures cannot achieve effective all-round fit and are prone to forming support dead angles.

[0003] Existing clamping devices, when handling thin-walled cylindrical automotive parts, suffer from low initial deformation and centering accuracy due to rigid clamping, which affects the roundness of the weld. Furthermore, they lack a flexible adaptive mechanism and cannot effectively cope with the irregularity of the inner wall of the part and the thermal deformation during the welding process, leading to welding stress concentration or even cracking. Based on this, we propose an automotive part clamping device and process based on circumferential welding to solve the above problems. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an automotive parts clamping device and process based on circumferential welding. Through flexible support, it facilitates the clamping of thin-walled cylindrical automotive parts, solving the problem that existing clamping devices suffer from initial deformation and low centering accuracy of parts due to rigid clamping, which affects the roundness of the weld.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an automotive parts clamping device based on circumferential welding, comprising an integral base, a first movable seat and a second movable seat respectively installed at both ends of the integral base along its length, and driving components installed at both ends of the integral base along its length. The output ends of the two driving components are respectively connected to the first movable seat and the second movable seat, and are used to drive the first movable seat and the second movable seat to move towards each other or away from each other and adjust the distance between them. The upper end of the first movable seat is fixedly installed with a first column. The upper end of the first column is rotatably installed with a bearing seat. One end of the gripper disc is located on one side of the bearing seat and a drive docking part is provided. The other end of the gripper disc is located on the other side of the bearing seat and a clamping assembly is provided. The clamping assembly is used to clamp and fix the end of the thin-walled cylindrical part. The clamping assembly includes three clamping heads arranged in a ring array, a transmission assembly set in the jaw disk, and a hydraulic motor set on the surface of the jaw disk. The output end of the hydraulic motor is connected to the transmission assembly. The transmission assembly is used to synchronously drive the three clamping heads to move closer or further apart. A positioning assembly is set on the left end face of the clamping head. The positioning assembly is used to position and clamp the thin-walled cylindrical part. The upper end of the second movable seat is fixedly connected to a second column, and the upper end of the second column is provided with a support mechanism. The support mechanism includes a push cylinder and a support head. The push cylinder is used to push the support head closer to or away from the gripper plate. A follow-up support assembly is provided on the outside of the support head. The follow-up support assembly is used to support the welding end of the thin-walled cylindrical part. The clamping end of the gripper plate and the support head are arranged opposite to each other, so as to cooperate with the clamping assembly. The clamping assembly fixes the part, while the follow-up support assembly supports the other end of the part and maintains concentricity with the clamping assembly.

[0006] Furthermore, the overall base has a U-shaped structure, and guide rails are fixedly installed on both the front and rear sides of the upper end of the overall base. The bottom sides of the first and second movable seats are slidably connected to the upper end of the overall base through the guide rails, and an isolation plate is fixedly connected to the inner side of the overall base.

[0007] Furthermore, the drive assembly includes a threaded rod rotatably mounted on the left and right ends of the isolation plate, and a first nut seat threaded onto the threaded rod. The upper ends of the two first nut seats are fixedly connected to the bottom of the first movable seat and the second movable seat, respectively (a protective cover needs to be added between the first movable seat and the second movable seat, preferably an accordion-style structure, which can be adapted to the movement adjustment of the first movable seat and the second movable seat). The end of the threaded rod away from the isolation plate is rotatably connected to the left and right ends of the overall base through a bearing bracket. Servo motors are provided at both ends of the overall base. The output end of the servo motor is connected to the threaded rod to drive the threaded rod to rotate. When the threaded rod rotates, the first nut seat synchronously drives the first movable seat or the second movable seat to move laterally.

[0008] Furthermore, the gripper disc has an annular cavity inside, and three connecting slots arranged in an annular array are formed on the left end face of the gripper disc. The connecting slots communicate with the annular cavity, and the three clamping heads are slidably embedded in the three connecting slots respectively. A T-shaped block is fixed to the right end of each clamping head. The T-shaped block extends into the annular cavity, and a helical meshing groove is formed on the right end face of the T-shaped block. The output shaft of the hydraulic motor extends into the gripper disc and is connected to the transmission component to drive the transmission component to move. In turn, the three clamping heads are driven to synchronously contract or expand radially through the helical meshing groove.

[0009] Furthermore, the transmission assembly includes an annular transmission plate slidably mounted in the annular cavity and a bevel gear rotatably mounted on the inner wall of the annular cavity. The left end face of the annular transmission plate is provided with helical teeth, which mesh with a helical meshing groove. The right end of the annular transmission plate is provided with bevel teeth, which mesh with the bevel gear. The output end of the hydraulic motor is connected to the bevel gear. The hydraulic motor is used to drive the bevel gear to rotate. When the hydraulic motor drives the bevel gear to rotate, it drives the annular transmission plate to rotate around the axis. The helical transmission of the helical teeth and the helical meshing groove converts the rotational motion of the annular transmission plate into the radial linear motion of the three clamping heads.

[0010] Furthermore, the positioning assembly includes an outer guide roller disposed on one side of the clamping head surface, two inner supports symmetrically disposed on the other side of the clamping head surface, and a deformation contact element disposed on the contact surface of the inner supports. The outer guide roller is used to conform to the outer wall of the thin-walled cylindrical part, and the inner supports are used to extend into the interior of the thin-walled cylindrical part. A synchronization component is provided in the clamping head to adjust the relative distance between the outer guide roller and the inner supports to accommodate parts with different wall thicknesses. The deformation contact element is a deformation capsule filled with magnetorheological fluid. A magnetic field coil is embedded and installed inside the clamping head. The magnetic field coil is arranged around the deformation capsule. The magnetic field coil is used to generate a magnetic field after being energized to change the viscosity of the magnetorheological fluid, thereby adjusting the stiffness of the deformation capsule and the adaptive support force on the inner wall of the part.

[0011] It is important to note that magnetorheological fluid (MRF) is composed of micron-sized magnetic particles dispersed in a non-conductive carrier fluid (such as silicone oil). During the initial radial contraction of the clamping head, the magnetic field coil is not energized or only slightly energized. At this stage, the MRF is in a Newtonian fluid state with extremely low viscosity, and the deformation capsule exhibits excellent flexibility. This allows the deformation capsule to flow like a fluid into the microscopic unevenness or irregular corners of the part's inner wall, achieving seamless full-surface bonding. Once the outer guide roller and inner support have achieved wall thickness matching and the part's position is confirmed, the control system applies a rated voltage (e.g., 12V-24V DC) to the magnetic field coil, generating a flow perpendicular to the MRF. A strong magnetic field (typically 0.3T-0.6T) is applied in the direction of the magnetic field. Under the influence of the magnetic field, the magnetic particles in the magnetorheological fluid instantly align into a chain-like structure along the direction of the magnetic field lines, causing the liquid to undergo a phase change within milliseconds. The yield strength increases sharply, exhibiting solid-like characteristics. At this time, the flexibility and elasticity of the deformation bladder decrease, providing sufficient radial support force for the part to resist cutting forces or welding gravity, preventing micro-movements during processing. Furthermore, during the welding process, the control system can adjust the current of the magnetic field coil in real time through PWM (pulse width modulation), thereby linearly adjusting the apparent viscosity of the magnetorheological fluid and the damping characteristics of the deformation bladder, achieving dynamic adaptive adjustment of stiffness. Traditional rubber bushings, while flexible, have limited support and are prone to aging, while metal bushings offer strong support but are easily damaged by thin-walled parts. By utilizing the reversible rheological properties of magnetorheological fluid, the same support structure combines the compliance of rubber with a certain degree of rigidity. The outer skin of the deformation bladder is made of polyurethane or fluororubber material that is resistant to high pressure and high temperature and has a low coefficient of friction. This ensures effective penetration of the magnetic field while isolating the magnetorheological fluid from direct contact with the parts. This ensures that the device can adapt to parts with complex internal cavity structures such as reinforcing ribs and constrictions (by filling dead corners through the fluidity of the liquid state) and is easy to adapt to surface indentations and elliptical deformations of thin-walled parts.

[0012] Furthermore, the synchronization component includes a movable cavity inside the clamping head, a double-ended lead screw 1 rotatably installed in the movable cavity, movable blocks threaded onto the upper and lower ends of the double-ended lead screw 1, a slide groove on the surface of the clamping head, and a connecting block slidably installed in the slide groove. There are three slide grooves on the surface of the clamping head. The outer guide roller is rotatably connected to one of the connecting blocks via a connecting shaft. The two inner support seats are fixedly connected to the other two connecting blocks respectively. A power motor is installed at the bottom of the clamping head. The output end of the power motor is connected to the double-ended lead screw 1, driving the double-ended lead screw 1 to rotate, causing the two movable blocks to move synchronously in opposite directions, thereby driving the outer guide roller and the inner support seats to move closer or further apart.

[0013] Furthermore, the support mechanism also includes a fixed base fixedly installed on the upper end of the second column, a support head fixedly installed on the surface of the fixed base, one end of the support head being rotatably installed on the fixed base through a mounting bushing and connected to the output end of the push cylinder; the follow-up support assembly includes an upper support plate set above the support head, five inner support plates arranged in a ring array on the outside of the support head, and an adjustment assembly set in the support head. The main structure of the support head is a regular hexagonal prism. An assembly groove is opened on the upper end face of the upper support plate. An upper floating plate is slidably installed in the assembly groove. The lower end face of the upper floating plate is covered with a porous ceramic layer. A high-pressure gas interface is provided on the surface of the mounting bushing. An airflow channel is opened inside the upper support plate. Multiple air floating holes are opened at the bottom of the assembly groove. The air floating holes are connected to the high-pressure gas interface through the airflow channel. An external air source enters through a high-pressure gas interface and is ejected upward through the airflow channel and air float hole, forming an air film between the upper floating plate and the bottom of the assembly slot. This allows the upper floating plate to float with the slight deformation of the inner wall of the part and provide flexible support.

[0014] It is important to note that the clamping assembly and the follower support assembly work together to form a comprehensive stable constraint system for the thin-walled cylindrical part. The clamping assembly on the first moving seat is mainly responsible for the rotational drive transmission of the part, the establishment of the axial positioning reference, and the initial radial centering function. The follower support assembly on the second moving seat is mainly responsible for the intermediate anti-collapse support of the part with a length-to-diameter ratio, the compensation for welding thermal deformation, and the reduction of rotational friction resistance. This forms a top clamping and a multi-point balanced support in the radial direction, ensuring the coaxiality accuracy of the part during high-speed rotation or static welding.

[0015] Furthermore, the adjustment assembly includes a rotary motor, a double-ended lead screw, two second nut seats, six positioning blocks, and six hinge components. A lead screw cavity is axially formed at the center of the support head. The double-ended lead screw is rotatably mounted within the lead screw cavity. The rotary motor is fixed to the right end face of the support head, and its output shaft is connected to the double-ended lead screw. The two second nut seats are threaded onto both ends of the double-ended lead screw. The two ends of the double-ended lead screw have the same pitch but opposite threads. Radially extending guide grooves are formed on all six outer surfaces of the support head. The six positioning blocks are slidably mounted within these guide grooves, with the inner end of each positioning block extending into the lead screw cavity and fixedly connected to the corresponding second nut seat. The outer end of each positioning block is rotatably connected to the inner side of the upper support plate or inner support plate via hinge components. When the rotary motor drives the double-ended lead screw to rotate, it causes the two second nut seats to move towards or away from each other. Through the linkage of the positioning blocks and hinge components, the upper support plate and the five inner support plates are driven to extend or retract radially synchronously.

[0016] A ring welding process, employing the aforementioned automotive parts clamping device, includes the following steps: S1. Initial Reset: The drive assembly puts the first and second moving seats at the maximum distance, controls the three clamping heads of the clamping assembly to be fully open, and controls the upper support plate and inner support plate of the follow-up support assembly to be fully retracted. S2. Loading and rough positioning: Place the thin-walled cylindrical part to be welded between the first moving seat and the second moving seat, so that one end of the part is in contact with the clamping head area and the other end is aligned with the support head. S3, Axial clamping: Start the drive assembly to control the first and second moving seats to move towards each other until the support head is inserted into the other end of the part. At the same time, the push cylinder is activated to push the support head to move further to the left, so that the part is pressed between the clamping assembly and the support head. S4, Radial adaptive clamping: S41. Start the hydraulic motor to drive the clamping head to retract radially, so that the outer guide roller fits against the outer wall of the part and the inner support enters the inner wall of the part. S42. Start the power motor and adjust the distance between the outer guide roller and the inner support to match the wall thickness of the part. S43. By energizing the magnetic field coil, the stiffness of the deformation capsule is adjusted to achieve flexible centering clamping of the end of the part. S5, Internal follow-up support: S51. Start the rotary motor to drive the upper support plate and inner support plate to extend radially until they are in close contact with the inner wall of the part. S52. Open the high-pressure gas interface to supply air to the air float hole in the upper support plate to form an air float support layer, reduce friction and compensate for the roundness error of the parts. S6. Circumferential welding: Start the rotation drive mechanism of the gripper disc or keep it stationary to cooperate with the external welding gun to perform circumferential welding. During the welding process, the follow-up support component adjusts the support force in real time according to the thermal deformation of the part. S7. Unloading: After welding is completed, the power supply to the magnetic field coil is cut off, the high-pressure gas is released, the actuators are controlled to reverse and reset, and the finished parts are removed.

[0017] Compared with the prior art, the technical solution of this application has the following beneficial effects: 1. This invention positions thin-walled cylindrical parts using an outer guide roller, while the inner side is contacted by an inner support seat, forming an outer guide and inner support structure. At the same time, the outer guide roller and the inner support seat clamp the tube wall and form a bidirectional constraint. The symmetrical force structure avoids the elliptical deformation caused by the single-point radial extrusion of the traditional three-jaw chuck, ensuring the geometric integrity of the thin-walled cylindrical parts in the initial clamping stage. This provides a stable reference for subsequent high-precision circumferential welding, avoids local stress concentration, and significantly improves the roundness and concentricity of the weld. 2. The present invention sets a deformation bladder filled with magnetorheological fluid on the surface of the inner support seat and controls it with a magnetic field coil. When no power is applied or the field strength is low, the deformation bladder is fluid and can automatically fill the irregular gaps and micro depressions on the inner wall of the part, achieving a seamless fit. After being powered on, it quickly solidifies to provide a certain support, eliminating local high pressure marks caused by rigid contact. It effectively adapts to automotive pipe parts with complex internal structures and ensures the self-adaptive capability of clamping. 3. The present invention provides a support head and a follow-up support assembly driven by a push cylinder at the other end of the part. By adjusting the distance between the first and second moving seats through the drive assembly, the follow-up support unit can accurately abut against the far end of the part, forming a double-end support structure, which effectively resists the bending deformation caused by the weight of the part, ensures the coaxiality of the long pipe in the entire axial range, and prevents the misalignment caused by eccentricity during the welding process; 4. The present invention uses a wide upper support plate to increase the support area and directly support the softened area below the weld, preventing the weld from sagging due to gravity and causing it to become concave. In addition, the high-pressure gas ejected from the porous ceramic layer forms a gas film, so that the upper support plate is in a non-contact or micro-contact state with the inner wall of the part, which greatly reduces the rotational friction, avoids the mechanical support from scratching the high-temperature softened material, and ensures the support effect. 5. This invention utilizes a servo motor on the overall base to drive a threaded rod, which can steplessly adjust the axial distance between the first and second moving seats to accommodate parts of different lengths. At the same time, the wall thickness gap of the clamping head and the radial diameter of the support head are adjusted by the power motor and the rotary motor respectively, which facilitates compatibility with parts of different specifications and sizes. It also ensures that the geometric center and rotation center of parts of different specifications are highly coincident after clamping, thus guaranteeing welding quality. Attached Figure Description

[0018] Figure 1 The diagram shown is a schematic representation of the overall structure of the present invention. Figure 2 The diagram shown is a top view of the overall base structure of the present invention; Figure 3 The diagram shown is a schematic representation of the first column structure of the present invention; Figure 4 The diagram shown is a schematic representation of the gripper disk structure of the present invention. Figure 5 The diagram shown is a schematic representation of the internal structure of the annular cavity of the present invention. Figure 6 The diagram shown is a schematic representation of the surface structure of the gripper disk of the present invention. Figure 7 The diagram shown is a schematic of the clamping head structure of the present invention; Figure 8 The diagram shown is a schematic representation of the internal structure of the active cavity of the present invention. Figure 9 The diagram shown is a schematic representation of the fixing base structure of the present invention; Figure 10 The diagram shown is a schematic representation of the internal structure of the lead screw cavity of the present invention.

[0019] Explanation of reference numerals in the attached drawings: 1. Overall base; 101. Guide slide rail; 102. Isolation plate; 103. Threaded rod; 104. First nut seat; 105. Servo motor; 2. First moving seat; 3. Second moving seat; 4. First column; 5. Bearing seat; 6. Gripper plate; 61. Clamping head; 611. T-block; 612. Connecting groove; 613. Spiral meshing groove; 62. Hydraulic motor; 63. Annular cavity; 631. Annular transmission plate; 632. Bevel gear; 601. Outer guide roller; 602. Inner support seat; 603. Deformation bladder; 6011. Movable cavity 6012, Double-ended lead screw one; 6013, Moving block; 6014, Slide groove; 6015, Connecting block; 6016, Power motor; 7, Second column; 8, Fixed seat; 9, Mounting bushing; 10, Push cylinder; 11, Support head; 111, Upper support plate; 112, Inner support plate; 113, Assembly groove; 114, Upper floating plate; 115, Porous ceramic layer; 1101, Rotary motor; 1102, Lead screw cavity; 1103, Double-ended lead screw two; 1104, Second nut seat; 1105, Guide groove; 1106, Positioning block; 1107, Hinge component. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figures 1-10This embodiment discloses an automotive parts clamping device based on circumferential welding, comprising an integral base 1, a first movable seat 2 and a second movable seat 3 respectively installed at both ends along the length of the integral base 1. Drive components are installed at both ends along the length of the inner side of the integral base 1. The output ends of the two drive components are connected to the first movable seat 2 and the second movable seat 3 respectively, for driving the first movable seat 2 and the second movable seat 3 to move towards or away from each other and adjusting the distance between them. The integral base 1 has a U-shaped structure, and the front and rear sides of the upper end of the integral base 1 are fixedly mounted with… Equipped with guide rails 101, the bottom sides of the first movable seat 2 and the second movable seat 3 are slidably connected to the upper end of the integral base 1 via the guide rails 101. An isolation plate 102 is fixedly connected to the inner side of the integral base 1. A first column 4 is fixedly installed on the upper end of the first movable seat 2. A 6 is rotatably installed on the upper end of the first column 4 via a bearing seat 5. One end of the gripper disc 6 is located on one side of the bearing seat 5 and has a drive docking component. The drive docking component is driven by an external rotational power source, such as a servo... The other end of the gripper disk 6, located on the other side of the bearing housing 5, is equipped with a clamping assembly for clamping and fixing the end of the thin-walled cylindrical part. The clamping assembly includes three clamping heads 61 arranged in a ring array, a transmission assembly disposed in the gripper disk 6, and a hydraulic motor 62 disposed on the surface of the gripper disk 6. The hydraulic motor 62 is a low-speed, high-torque radial piston hydraulic motor. The output end of the hydraulic motor 62 is connected to the transmission assembly, which is used to synchronously drive the three clamping heads 61 to move closer or further apart. The left end face of the clamping head 61 is provided with... A positioning component is provided for positioning and clamping the thin-walled cylindrical part; a second column 7 is fixedly connected to the upper end of the second movable seat 3, and a support mechanism is provided at the upper end of the second column 7. The support mechanism includes a push cylinder 10, which is a standard double-acting cylinder, and a support head 11. The push cylinder 10 is used to push the support head 11 closer to or away from the gripper disk 6. A follow-up support component is provided on the outside of the support head 11. The follow-up support component is used to support the welding end of the thin-walled cylindrical part, and the clamping end of the gripper disk 6 and the support head 11 are arranged opposite to each other.

[0022] It should be noted that during the ring welding process, metal spatter, welding slag, and coolant drips are inevitably generated. An accordion-style protective cover is installed between the first moving seat 2 and the second moving seat 3 to prevent welding slag from falling into the threaded pair or motor bearing and causing jamming or damage. At the same time, the guide slide rail 101 adopts a high-rigidity linear guide rail to ensure the parallelism and straightness of the first moving seat 2 and the second moving seat 3 during long-distance movement. The clamping assembly and the follow-up support assembly form a clamping limit on both ends of the part, and the outer guide and inner support structure are realized simultaneously to ensure the concentricity of the long strip part.

[0023] In this embodiment, the driving component includes a threaded rod 103 rotatably mounted on the left and right ends of the isolation plate 102, and a first nut seat 104 threaded onto the threaded rod 103. The upper ends of the two first nut seats 104 are fixedly connected to the bottom of the first movable seat 2 and the second movable seat 3, respectively. The end of the threaded rod 103 away from the isolation plate 102 is rotatably connected to the left and right ends of the integral base 1 through a bearing bracket. A servo motor 105 is provided on both the left and right ends of the integral base 1. The output end of the servo motor 105 is connected to the threaded rod 103 and is used to drive the threaded rod 103 to rotate. When the threaded rod 103 rotates, the first nut seat 104 synchronously drives the first movable seat 2 or the second movable seat 3 to move laterally.

[0024] It should be noted that the first moving seat 2 and the second moving seat 3 are controlled separately, thus driven by two servo motors 105 to move towards or away from each other. The threaded rod 103 and the first nut seat 104 have a self-locking characteristic. During the welding process, even if subjected to a large axial thrust or vibration, the moving seat can maintain its position locked and will not cause accidental displacement, thus ensuring the stability of the welding process.

[0025] In this embodiment, another implementation of the drive component adopts a gear and rack meshing drive structure. The rack is fixed inside the overall base 1, and the gear driven by the servo motor is installed at the bottom of the moving seat, which is suitable for clamping large pipe fittings with ultra-long stroke.

[0026] Please see Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 In this embodiment, the gripper disk 6 has an annular cavity 63 inside, and three connecting grooves 612 arranged in an annular array are opened on the left end face of the gripper disk 6. The connecting grooves 612 communicate with the annular cavity 63. The three clamping heads 61 are slidably embedded in the three connecting grooves 612 respectively. A T-shaped block 611 is fixed to the right end of each clamping head 61. The T-shaped block 611 extends into the annular cavity 63, and a spiral engagement groove 613 is opened on the right end face of the T-shaped block 611. The output shaft of the hydraulic motor 62 extends into the gripper disk 6 and is connected to the transmission assembly to drive the transmission assembly to move, thereby driving the three clamping heads 61 to synchronously contract or expand radially through the spiral engagement groove 613.

[0027] It should be noted that the fit between the T-block 611 and the connecting groove 612 restricts the axial degree of freedom of the clamping head 61. The screw pair has a certain degree of self-locking. When the hydraulic motor 62 stops working, the clamping head 61 can remain in the current radial position and will not retract due to the reaction force of the parts, thus ensuring the constant clamping force.

[0028] In this embodiment, the transmission assembly includes an annular transmission plate 631 slidably mounted in an annular cavity 63 and a bevel gear 632 rotatably mounted on the inner wall of the annular cavity 63. The left end face of the annular transmission plate 631 is provided with helical teeth, which mesh with a helical meshing groove 613. The right end of the annular transmission plate 631 is provided with bevel teeth, which mesh with the bevel gear 632. The output end of the hydraulic motor 62 is connected to the bevel gear 632. The hydraulic motor 62 is used to drive the bevel gear 632 to rotate. When the hydraulic motor 62 drives the bevel gear 632 to rotate, it drives the annular transmission plate 631 to rotate around the axis. The helical transmission of the helical teeth and the helical meshing groove 613 converts the rotational motion of the annular transmission plate 631 into the radial linear motion of the three clamping heads 61.

[0029] It should be noted that the power of the hydraulic motor 62 is input through the bevel gear 632, and the meshing with the annular transmission plate 631 realizes the change of power direction, thereby driving the annular transmission plate 631 to rotate, synchronously driving the three clamping heads 61 to move, and ensuring the absolute synchronicity of the movement of the three clamping heads 61. This ensures that the three clamping heads 61 always move radially around the same center point, which facilitates synchronizing the clamping axis of the part with the jaw disk 6.

[0030] Please see Figure 1 , Figure 4 , Figure 5 , Figure 7 and Figure 8 In this embodiment, the positioning component includes an outer guide roller 601 disposed on one side of the surface of the clamping head 61, two inner support seats 602 symmetrically disposed on the other side of the surface of the clamping head 61, and a deformation contact element disposed on the contact surface of the inner support seats 602. The outer guide roller 601 is used to fit against the outer wall of the thin-walled cylindrical part, and the inner support seats 602 are used to extend into the interior of the thin-walled cylindrical part. A synchronization component is provided in the clamping head 61 to adjust the relative distance between the outer guide roller 601 and the inner support seats 602 to adapt to parts with different wall thicknesses. The deformation contact element is a deformation capsule 603 filled with magnetorheological fluid. A magnetic field coil (the magnetic field coil is a hollow coil wound with high-temperature resistant enameled wire and connected to an external DC regulated power supply) is embedded and installed inside the clamping head 61. The magnetic field coil is arranged around the deformation capsule 603. The magnetic field coil is used to generate a magnetic field after being energized to change the viscosity of the magnetorheological fluid, thereby adjusting the stiffness of the deformation capsule 603 and the adaptive support force on the inner wall of the part.

[0031] It should be noted that the apparent viscosity of the magnetorheological fluid (MRF) changes rapidly and reversibly with the strength of the applied magnetic field. The control logic of the magnetic field coil is divided into two stages: The first stage is the flexible bonding stage, in which the coil is not energized or is energized with a weak current (such as 0.5A). The magnetorheological fluid is in a low-viscosity fluid state, and the deformation capsule 603 is extremely soft, able to flow into the microscopic unevenness of the inner wall of the part or the corner of the irregular cross section like a liquid, achieving gapless full-surface contact and eliminating the stress concentration points caused by traditional rigid support. The second stage is the rigid locking stage. After the clamping position is determined, a strong current (such as 2.0A-3.0A) is passed through the coil to generate a strong magnetic field. The magnetorheological fluid solidifies instantly, and the yield strength of the deformation capsule 603 increases sharply, becoming a near-solid state, providing strong radial support to resist welding vibration and cutting force.

[0032] In this embodiment, the synchronization component includes a movable cavity 6011 formed inside the clamping head 61, a double-ended lead screw 6012 rotatably installed in the movable cavity 6011, movable blocks 6013 threaded onto the upper and lower ends of the double-ended lead screw 6012, a sliding groove 6014 formed on the surface of the clamping head 61, and a connecting block 6015 slidably installed in the sliding groove 6014. Three sliding grooves 6014 are provided on the surface of the clamping head 61. The outer guide roller 601 is connected to one of the connecting blocks 6015 via a connecting shaft. The 015 is rotatably connected, and the two inner support seats 602 are fixedly connected to the other two connecting blocks 6015 respectively. The bottom of the clamping head 61 is equipped with a power motor 6016 (the power motor 6016 is a small stepper motor or servo motor with encoder feedback). The output end of the power motor 6016 is connected to the double-headed lead screw 6012, which drives the double-headed lead screw 6012 to rotate, so that the two moving blocks 6013 move synchronously in opposite directions, thereby driving the outer guide roller 601 and the inner support seat 602 to move closer or further away from each other.

[0033] It should be noted that the three grooves 6014 provide channels for the connection of the outer guide roller 601, the inner support 602 and the moving block 6013, respectively. The two ends of the double-ended lead screw 6012 have opposite threads, which ensures that the two moving blocks 6013 always move in opposite directions and at the same speed. This allows the outer guide roller 601 and the inner support 602 to open and close symmetrically with the theoretical center line of the part as the reference. The power motor 6016 adjusts the outer guide roller 601 and the inner support 602 to a state where they just contact the inner and outer walls of the part. The center line of the part will then coincide with the geometric center of the clamping head 61, which improves the versatility of the equipment and production efficiency.

[0034] Please see Figure 1 , Figure 9 and Figure 10In this embodiment, the support mechanism further includes a fixed base 8 fixedly installed on the upper end of the second column 7, and a support head 11 fixedly installed on the surface of the fixed base 8. One end of the support head 11 is rotatably installed on the fixed base 8 through a mounting bushing 9 and connected to the output end of the push cylinder 10. The follow-up support assembly includes an upper support plate 111 disposed above the support head 11, five inner support plates 112 arranged in a ring array on the outside of the support head 11, and an adjustment assembly disposed in the support head 11. The main structure of the support head 11 is a regular hexagonal prism. An assembly groove 113 is opened on the upper end surface of the upper support plate 111, and an upper support plate 112 is slidably installed in the assembly groove 113. The upper floating plate 114 has a porous ceramic layer 115 covering its lower end surface (the porous ceramic layer 115 is made of alumina porous ceramic with uniform pore size and good air permeability). The surface of the mounting bushing 9 is provided with a high-pressure gas interface. An airflow channel is opened inside the upper support plate 111. Multiple air floating holes are opened at the bottom of the assembly groove 113. The air floating holes are connected to the high-pressure gas interface through the airflow channel. An external air source enters through the high-pressure gas interface and is sprayed upward through the airflow channel and air floating holes, forming an air film between the upper floating plate 114 and the bottom of the assembly groove 113, so that the upper floating plate 114 can float with the slight deformation of the inner wall of the part and provide flexible support.

[0035] It should be noted that during the circumferential welding process, the temperature in the weld area is extremely high and the material softens. If rigid support is used, the thermal expansion of the parts will be constrained, resulting in huge thermal stress, which may cause the weld to crack or deform. However, the upper floating plate 114 achieves elastic contact through air film suspension, which not only provides support to the welding area but also reduces the impact of contact friction on the softened material.

[0036] In this embodiment, a mechanical spring buffer structure can be used instead of an air flotation structure between the upper floating plate 114 and the assembly groove 113. Multiple compression springs are set at the bottom of the assembly groove to support the upper floating plate. Although the coefficient of friction is slightly higher than that of air flotation, the structure is simple and does not require an air source. It is suitable for occasions where the surface finish requirement is slightly lower or where there is no air source.

[0037] Please see Figure 9 and Figure 10In this embodiment, the adjustment assembly includes a rotary motor 1101 (a hollow shaft servo motor is selected for easy cable passage), a double-ended lead screw 1103, two second nut seats 1104, six positioning blocks 1106, and six hinge components 1107. A lead screw cavity 1102 is axially formed at the center of the support head 11. The double-ended lead screw 1103 is rotatably mounted within the lead screw cavity 1102. The rotary motor 1101 is fixed to the right end face of the support head 11. The output shaft of the rotary motor 1101 is connected to the double-ended lead screw 1103. The two second nut seats 1104 are threaded onto both ends of the double-ended lead screw 1103. The two ends of the double-ended lead screw 1103 have the same pitch but opposite threads. Radially extending guide grooves 1105 are provided on all six outer surfaces. Six positioning blocks 1106 are slidably installed in the guide grooves 1105, and the inner end of each positioning block 1106 extends to the lead screw cavity 1102 and is fixedly connected to the corresponding second nut seat 1104. The outer end of each positioning block 1106 is rotatably connected to the inner side of the upper support plate 111 or the inner support plate 112 through the hinge 1107. When the rotary motor 1101 drives the double-headed lead screw 1103 to rotate, it drives the two second nut seats 1104 to move towards or away from each other. Through the linkage of the positioning blocks 1106 and the hinge 1107, the upper support plate 111 and the five inner support plates 112 are driven to extend or retract radially in sync.

[0038] It should be noted that the linear motion of the double-ended lead screw 1103 is converted into the radial motion of the upper support plate 111 and the inner support plate 112 through the hinge 1107. Due to the hinge angle, a small axial displacement can be converted into a large radial extension, which improves the sensitivity and range of adjustment. The regular hexagonal layout makes the support force more evenly distributed in the circumferential direction. The six-point support can better constrain the roundness of the parts and prevent polygonal deformation of the parts during rotation. At the same time, all support plates are driven by the same motor, which ensures the high synchronization of the action and ensures the consistency between the support center and the axis of the parts, further improving the clamping rigidity of parts with a length-to-diameter ratio.

[0039] In this embodiment, the present invention provides a ring welding process, including the following steps: S1. Initial Reset: The controller (Siemens S7-1200PLC) issues a command to drive the first moving seat 2 and the second moving seat 3 to the maximum distance state, control the three clamping heads 61 of the clamping assembly to be fully open, control the upper support plate 111 and the inner support plate 112 of the follow-up support assembly to be fully retracted, and each sensor (limit switch, origin sensor) confirms that the reset is complete. S2. Loading and rough positioning: Place the thin-walled cylindrical part to be welded between the first moving seat 2 and the second moving seat 3, so that one end of the part is in contact with the clamping head 61 area and the other end is aligned with the support head 11. The part can be roughly centered by a visual recognition system or manual assistance. S3, Axial clamping: Start the drive assembly to control the first moving seat 2 and the second moving seat 3 to move towards each other. The servo motor 105 quickly approaches according to the preset part length. When the distance is close to the set value, it slows down until the support head 11 is inserted into the other end of the part. Then, the push cylinder 10 is activated to push the support head 11 to move further to the left and apply a constant axial preload force so that the part is pressed between the clamping assembly and the support head 11. S4, Radial adaptive clamping: S41. Start the hydraulic motor 62 to drive the clamping head 61 to retract radially, so that the outer guide roller 601 fits against the outer wall of the part and the inner support 602 enters the inner wall of the part. At this time, the magnetic field coil is not energized and the deformation bladder 603 is in a soft state. S42, Wall thickness adaptation: Start the power motor 6016, adjust the distance between the outer guide roller 601 and the inner support 602, the system monitors the current feedback of the power motor 6016, when the current reaches a peak, it is determined that the contact is in place, and the adjustment is stopped to match the actual wall thickness of the part and eliminate eccentricity. S43, Stiffness Locking: When the magnetic field coil is energized, the stiffness of the deformation capsule 603 is adjusted. The current gradually rises to the rated value, and the magnetorheological fluid changes from liquid to semi-solid / solid state, realizing flexible centering clamping of the end of the part and absorbing high-frequency vibration. S5, Internal follow-up support: S51, Radial Expansion: Start the rotary motor 1101 to drive the upper support plate 111 and inner support plate 112 to extend radially. By monitoring the motor current or displacement sensor, the extension continues until the parts are in close contact with the inner wall, thus establishing basic support. S52, Air Float Activation: Open the high-pressure gas interface (pressure set to 0.4-0.6MPa) to supply air to the air float hole in the upper support plate 111. The gas overflows evenly through the porous ceramic layer 115 and forms a stable gas film between the upper float plate 114 and the pipe wall. The air pressure sensor monitors in real time to ensure the stability of the gas film, thereby reducing friction and compensating for the roundness error of the parts. S6. Circumferential welding: Start the rotation drive mechanism of the gripper disk 6 to drive the part to rotate, and cooperate with the fixed welding head to perform circumferential welding. During the welding process, the control system monitors the welding current and temperature in real time. If local overheating is detected, causing the part to soften and deform, the air flotation pressure can be increased appropriately or the magnetic field coil current can be finely adjusted so that the follow-up support component can finely adjust the support force in real time according to the thermal deformation of the part, release thermal stress, and prevent collapse. S7. Unloading: After welding, wait for the part to cool to a safe temperature. Cut off the power supply to the magnetic field coil, and the deformation bladder 603 returns to a liquid state; release the high-pressure gas, and the gas film disappears; control the rotary motor 1101, the power motor 6016, the hydraulic motor 62, and the push cylinder 10 to reverse and reset; drive the assembly to separate the moving seat and remove the finished part.

[0040] It should be noted that in step S3, the axial clamping adopts a strategy of coarse adjustment followed by fine clamping. The drive component first quickly adjusts the distance between the two moving seats to a position slightly smaller than the length of the part to achieve rapid positioning. Then, the push cylinder 10 intervenes to provide a constant axial preload. The phased control not only ensures clamping efficiency but also avoids damage to the end of the part or overload of the equipment caused by direct hard collision of the servo motor 105, thus ensuring the initial stability of the part axis. In step S4, the position adjustment of the clamping head 61 and the adjustment of the positioning component are mutually compatible. When clamping one side of the part, the position of the clamping head 61 is first adjusted to make the concentricity of the clamping head 61 match the part. Then, the outer guide roller 601 and the inner support seat 602 form a clamping limit on the part tube wall. In S41, the screw drive driven by the hydraulic motor 62 ensures the absolute synchronous self-centering of the three clamping heads 61. In S42, the power motor 6016 accurately matches the wall thickness, eliminating the clamping eccentricity caused by the wall thickness tolerance. In S43, the timing of energizing the magnetic field coil is strictly controlled after the mechanical contact is completed. At this time, the magnetorheological fluid changes from liquid to semi-solid / solid, locking the current geometry. In step S5, the internal follow-up support introduces a low-friction air-floating structure. In S52, an air-floating space is formed in the assembly groove 113 by an external air source, thereby reducing the contact friction between the upper support plate 111 and the pipe wall. During the ring welding process in S6, when the part undergoes slight bending or elliptical deformation due to uneven heating, the upper floating plate 114 can follow the movement of the inner wall of the part in real time under the action of air buoyancy, without generating a reaction force that hinders the deformation. This can release welding thermal stress and prevent stress concentration and collapse at the weld. In addition, the entire process is coordinated by a central control system (such as a PLC). Pressure sensors, displacement sensors and current feedback loops are set up between each step. For example, in S42, the system will determine whether the wall thickness is properly matched based on the current load; in S52, the air pressure sensor monitors the stability of the air film in real time. This closed-loop control ensures that automotive parts of different batches and specifications can obtain consistent high-quality clamping results.

[0041] It should be noted that the control method of the present invention is implemented through a controller. The control circuit of the controller can be implemented by those skilled in the art through simple programming. The power supply is also common knowledge in the field. Furthermore, since the present invention is mainly used to protect mechanical devices, the control method and circuit connection will not be explained in detail.

[0042] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for clamping an automobile part based on ring welding processing, characterized in that: It includes an integral base (1), a first movable seat (2) and a second movable seat (3) respectively installed at both ends of the integral base (1) along its length. Both ends of the integral base (1) along its length are equipped with drive components. The output ends of the two drive components are connected to the first movable seat (2) and the second movable seat (3) respectively, and are used to drive the first movable seat (2) and the second movable seat (3) to move closer to or further away from each other. The upper end of the first movable seat (2) is fixedly installed with a first column (4), and the upper end of the first column (4) is rotatably installed with (6) through the bearing seat (5). One end of the gripper disc (6) is provided with a drive docking part on one side of the bearing seat (5), and the other end of the gripper disc (6) is provided with a clamping assembly on the other side of the bearing seat (5). The clamping assembly is used to clamp and fix the end of the thin-walled cylindrical part. The clamping assembly includes three clamping heads (61) arranged in a ring array, a transmission assembly disposed in the jaw disk (6), and a hydraulic motor (62) disposed on the surface of the jaw disk (6). The output end of the hydraulic motor (62) is connected to the transmission assembly. The transmission assembly is used to synchronously drive the three clamping heads (61) to move closer or further apart. A positioning assembly is provided on the left end face of the clamping head (61). The positioning assembly is used to position and clamp the thin-walled cylindrical part. The upper end of the second movable seat (3) is fixedly connected to the second column (7). The upper end of the second column (7) is provided with a support mechanism, which includes a push cylinder (10) and a support head (11). The push cylinder (10) is used to push the support head (11) closer to or away from the gripper disk (6). The outer side of the support head (11) is provided with a follow-up support assembly, which is used to support the welding end of the thin-walled cylindrical part. The gripping end of the gripper disk (6) and the support head (11) are arranged opposite to each other.

2. The automotive parts clamping device based on circumferential welding as described in claim 1, characterized in that: The overall base (1) is a U-shaped structure. Guide rails (101) are fixedly installed on the front and rear sides of the upper end of the overall base (1). The bottom sides of the first movable seat (2) and the second movable seat (3) are slidably connected to the upper end of the overall base (1) through the guide rails (101). An isolation plate (102) is fixedly connected to the inner side of the overall base (1).

3. The automotive parts clamping device based on circumferential welding as described in claim 2, characterized in that: The drive assembly includes a threaded rod (103) rotatably mounted on the left and right ends of the isolation plate (102) and a first nut seat (104) threaded onto the threaded rod (103). The upper ends of the two first nut seats (104) are fixedly connected to the bottom of the first moving seat (2) and the second moving seat (3), respectively. The end of the threaded rod (103) away from the isolation plate (102) is rotatably connected to the left and right ends of the integral base (1) through a bearing bracket. Both the left and right ends of the integral base (1) are equipped with servo motors (105). The output end of the servo motor (105) is connected to the threaded rod (103) to drive the threaded rod (103) to rotate. When the threaded rod (103) rotates, the first nut seat (104) synchronously drives the first moving seat (2) or the second moving seat (3) to move laterally.

4. The automotive parts clamping device based on circumferential welding as described in claim 3, characterized in that: The gripper disk (6) has an annular cavity (63) inside. The left end face of the gripper disk (6) has three connecting grooves (612) arranged in an annular array. The connecting grooves (612) are connected to the annular cavity (63). The three clamping heads (61) are slidably embedded in the three connecting grooves (612). The right end of each clamping head (61) is fixed with a T-shaped block (611). The T-shaped block (611) extends into the annular cavity (63), and the right end face of the T-shaped block (611) has a spiral meshing groove (613). The output shaft of the hydraulic motor (62) extends into the gripper disk (6) and is connected to the transmission assembly to drive the transmission assembly to move. Then, the three clamping heads (61) are driven to synchronously contract or expand radially through the spiral meshing groove (613).

5. The automotive parts clamping device based on circumferential welding as described in claim 4, characterized in that: The transmission assembly includes an annular transmission plate (631) slidably mounted in the annular cavity (63) and a bevel gear (632) rotatably mounted on the inner wall of the annular cavity (63). The left end face of the annular transmission plate (631) is provided with helical teeth, which mesh with the helical meshing groove (613). The right end of the annular transmission plate (631) is provided with bevel teeth, which mesh with the bevel gear (632). The output end of the hydraulic motor (62) is connected to the bevel gear (632). The hydraulic motor (62) is used to drive the bevel gear (632) to rotate. When the hydraulic motor (62) drives the bevel gear (632) to rotate, it drives the annular transmission plate (631) to rotate around the axis. The helical transmission of the helical teeth and the helical meshing groove (613) converts the rotational motion of the annular transmission plate (631) into the radial linear motion of the three clamping heads (61).

6. The automotive parts clamping device based on circumferential welding as described in claim 5, characterized in that: The positioning assembly includes an outer guide roller (601) disposed on one side of the surface of the clamping head (61), two inner supports (602) symmetrically disposed on the other side of the surface of the clamping head (61), and a deformation contact element disposed on the contact surface of the inner supports (602). The outer guide roller (601) is used to fit against the outer wall of the thin-walled cylindrical part, and the inner supports (602) are used to extend into the interior of the thin-walled cylindrical part. A synchronization assembly is provided in the clamping head (61) to adjust the relative distance between the outer guide roller (601) and the inner supports (602) to accommodate parts with different wall thicknesses. The deformation contact element is a deformation capsule (603) filled with magnetorheological fluid. A magnetic field coil is embedded and installed inside the clamping head (61). The magnetic field coil is arranged around the deformation capsule (603). The magnetic field coil is used to generate a magnetic field after being energized to change the viscosity of the magnetorheological fluid, thereby adjusting the stiffness of the deformation capsule (603) and the adaptive support force on the inner wall of the part.

7. The automotive parts clamping device based on circumferential welding as described in claim 6, characterized in that: The synchronization component includes a movable cavity (6011) inside the clamping head (61), a double-ended lead screw (6012) rotatably mounted in the movable cavity (6011), movable blocks (6013) threaded onto the upper and lower ends of the double-ended lead screw (6012), a slide groove (6014) on the surface of the clamping head (61), and a connecting block (6015) slidably mounted in the slide groove (6014). Three slide grooves (6014) are provided on the surface of the clamping head (61). The outer guide roller (601) passes through... The connecting shaft is rotatably connected to one of the connecting blocks (6015), and the two inner support seats (602) are fixedly connected to the other two connecting blocks (6015) respectively. The bottom of the clamping head (61) is equipped with a power motor (6016). The output end of the power motor (6016) is connected to the first double-headed screw (6012), which drives the first double-headed screw (6012) to rotate, so that the two moving blocks (6013) move synchronously in opposite directions, thereby driving the outer guide roller (601) and the inner support seat (602) to move closer or further away from each other.

8. The automotive parts clamping device based on circumferential welding as described in claim 7, characterized in that: The support mechanism also includes a fixed seat (8) fixedly installed on the upper end of the second column (7), a support head (11) fixedly installed on the surface of the fixed seat (8), one end of the support head (11) is rotatably installed on the fixed seat (8) through the mounting bushing (9), and connected to the output end of the push cylinder (10); The follow-up support assembly includes an upper support plate (111) set above the support head (11), five inner support plates (112) arranged in a ring array on the outside of the support head (11), and an adjustment assembly set in the support head (11). The main structure of the support head (11) is a regular hexagonal prism. An assembly groove (113) is opened on the upper end face of the upper support plate (111). An upper floating plate (114) is slidably installed in the assembly groove (113). The lower end face of the upper floating plate (114) is covered with a porous ceramic layer (115). A high-pressure gas interface is provided on the surface of the mounting bushing (9). An airflow channel is opened inside the upper support plate (111). Multiple air floating holes are opened at the bottom of the assembly groove (113). The air floating holes are connected to the high-pressure gas interface through the airflow channel. An external air source enters through a high-pressure gas interface and is ejected upward through the airflow channel and air float hole, forming an air film between the upper floating plate (114) and the bottom of the assembly groove (113), enabling the upper floating plate (114) to float with the slight deformation of the inner wall of the part and provide flexible support.

9. The automotive parts clamping device based on circumferential welding as described in claim 8, characterized in that: The adjustment assembly includes a rotary motor (1101), a double-ended lead screw (1103), two second nut seats (1104), six positioning blocks (1106), and six hinge components (1107). A lead screw cavity (1102) is axially formed at the center of the support head (11). The double-ended lead screw (1103) is rotatably mounted within the lead screw cavity (1102). The rotary motor (1101) is fixed to the right end face of the support head (11). The output shaft of the rotary motor (1101) is connected to the double-ended lead screw (1103). The two second nut seats (1104) are threaded onto both ends of the double-ended lead screw (1103). The two ends of the double-ended lead screw (1103) have the same pitch but opposite threads. Radial openings are formed on all six outer surfaces of the support head (11). The extended guide groove (1105) has six positioning blocks (1106) that are slidably installed in the guide groove (1105). The inner end of each positioning block (1106) extends to the screw cavity (1102) and is fixedly connected to the corresponding second nut seat (1104). The outer end of each positioning block (1106) is rotatably connected to the inner side of the upper support plate (111) or the inner support plate (112) through the hinge (1107). When the rotary motor (1101) drives the double-headed screw (1103) to rotate, it drives the two second nut seats (1104) to move towards or away from each other. Through the linkage of the positioning block (1106) and the hinge (1107), the upper support plate (111) and the five inner support plates (112) are driven to extend or retract radially in sync.

10. A ring welding process, employing the automotive parts clamping device as described in claim 9, characterized in that: Includes the following steps: S1. Initial reset: The drive assembly puts the first moving seat (2) and the second moving seat (3) at the maximum distance, controls the three clamping heads (61) of the clamping assembly to be fully open, and controls the upper support plate (111) and inner support plate (112) of the follow-up support assembly to be fully retracted. S2, Loading and rough positioning: Place the thin-walled cylindrical part to be welded between the first moving seat (2) and the second moving seat (3), so that one end of the part is attached to the clamping head (61) area and the other end is aligned with the support head (11). S3, Axial clamping: Start the drive assembly to control the first moving seat (2) and the second moving seat (3) to move towards each other until the support head (11) is inserted into the other end of the part. At the same time, the push cylinder (10) moves to push the support head (11) to move further to the left, so that the part is pressed between the clamping assembly and the support head (11). S4, Radial adaptive clamping: S41. Start the hydraulic motor (62) to drive the clamping head (61) to retract radially, so that the outer guide roller (601) fits against the outer wall of the part and the inner support (602) enters the inner wall of the part; S42. Start the power motor (6016) and adjust the distance between the outer guide roller (601) and the inner support (602) to match the wall thickness of the part; S43. Energize the magnetic field coil and adjust the stiffness of the deformation capsule (603) to achieve flexible centering clamping of the end of the part. S5, Internal follow-up support: S51. Start the rotary motor (1101) to drive the upper support plate (111) and inner support plate (112) to extend radially until they are in close contact with the inner wall of the part; S52. Open the high-pressure gas interface and supply air to the air float hole in the upper support plate (111) to form an air float support layer, reduce friction and compensate for the roundness error of the parts. S6. Ring welding: Start the rotation drive mechanism of the gripper disc (6) or keep it stationary to cooperate with the external welding gun to perform ring welding. During the welding process, the follow-up support component adjusts the support force in real time according to the thermal deformation of the part. S7. Unloading: After welding is completed, the power supply to the magnetic field coil is cut off, the high-pressure gas is released, the actuators are controlled to reverse and reset, and the finished parts are removed.

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