An automobile parts welding auxiliary device

Abstract

This invention belongs to the field of component welding technology and discloses an auxiliary device for welding automotive components. The device includes a base, with a detachable positioning support assembly fixed to the upper end of the base. A variable-diameter conical ring to be welded is sleeved in the middle of the positioning support assembly. This invention achieves precise internal positioning of the variable-diameter conical ring and two sections of bellows in a single clamping operation using three coaxial integrated positioning rods. Synchronous welding with a dual-ring welding assembly at the same angular velocity eliminates secondary clamping errors and reduces secondary thermal shock and cumulative thermal damage to the conical ring. Simultaneously, the corrugated profile contact clamping of the corrugated pressing assembly prevents the thin-walled bellows from collapsing and stress concentration. Furthermore, a pre-welding impurity removal is achieved through an electromagnetically driven grinding and hammering integrated assembly combined with a cleaning assembly. The two-stage hammering—low force during welding and high force after welding—counters the solidification shrinkage stress, eliminates most of the residual tensile stress, and introduces surface compressive stress, significantly improving welding quality and ensuring the product quality and service life of the bellows.

Description

Technical Field

[0001] This invention belongs to the field of component welding technology, and in particular relates to an auxiliary device for welding automotive components. Background Technology

[0002] The variable-diameter exhaust flexible joint in the automotive exhaust system is a core vibration damping component. It is usually made up of a large-diameter bellows section, a variable-diameter cone ring, and a small-diameter bellows section welded together in sequence. It has the functions of absorbing engine vibration, compensating for thermal expansion deformation, and realizing the transition of exhaust pipe diameter. It is widely used in the exhaust systems of turbocharged engines and large-displacement engines.

[0003] Currently, the welding of variable-diameter bellows involves welding two circumferential seams sequentially, requiring two clamping of the workpiece. The secondary positioning error leads to a 1°–2° deviation in the coaxiality of the bellows at both ends. Furthermore, the two circumferential seams shrink asynchronously during welding, and the shrinkage force pulls the variable-diameter conical ring in one direction, causing an axial offset of 1–3 mm. This ultimately results in uneven bellows spacing, uneven load distribution during flexible joint operation, and a significant reduction in fatigue life. In addition, the weld metal shrinks as it cools, but is constrained by the surrounding cold substrate, resulting in tensile residual stress. Therefore, it is necessary to hammer the weld area during subsequent processing to eliminate the residual tensile stress. However, the cooling rate of thin-walled bellows is fast, and the optimal hammering temperature window is only a few seconds. Subsequent hammering often misses the optimal time, resulting in persistently high residual tensile stress and a high risk of stress corrosion and fatigue cracking. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an auxiliary device for welding automotive parts, addressing the shortcomings of the prior art.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: an auxiliary device for welding automotive parts, including a base, a positioning support assembly detachably fixed at the upper end of the base, a variable diameter conical ring to be welded sleeved in the middle of the positioning support assembly, and a large diameter corrugated pipe and a small diameter corrugated pipe symmetrically sleeved at both ends of the variable diameter conical ring on the positioning support assembly.

[0006] The upper end of the base is fixed with an external pressure assembly that is pressed against the outside of the variable diameter conical ring. The upper end of the base is also symmetrically fixed with two corrugated pressing assemblies that are respectively pressed against the outside of the large diameter corrugated pipe and the small diameter corrugated pipe. The upper end of the base is also symmetrically fixed with two annular welding assemblies located at the welding points of the variable diameter conical ring and the large diameter corrugated pipe, and the variable diameter conical ring and the small diameter corrugated pipe. The moving end inside the annular welding assembly is also fixed with a grinding and hammering integrated assembly and a cleaning assembly.

[0007] Preferably, the positioning support assembly includes a positioning rod, the middle part of which is configured as a first positioning section that matches the inner conical surface of the variable diameter conical ring, and the two sections of the positioning rod corresponding to the first positioning section are respectively configured as a second positioning section and a third positioning section that match the inner diameter of the large-diameter corrugated pipe and the small-diameter corrugated pipe;

[0008] The upper end of the base is detachably fixed with two symmetrically arranged fixing seats by bolts. The upper end of the fixing seat is fixed with a support rod, and the upper end of the support rod is fixed with a connecting frame. Both ends of the positioning rod are fixed with connecting blocks inserted into the connecting frame. The connecting blocks and the connecting frame are detachably fixed by bolts.

[0009] Preferably, the external pressure assembly includes a first upright fixed to the upper end of the base, a lower pressure seat fixed to the upper end of the first upright, and an upper pressure seat detachably fixed to the upper end of the lower pressure seat. The inner clamping surfaces of the lower pressure seat and the upper pressure seat are both set as conical surfaces that match the outer conical surface of the variable diameter conical ring. After the lower pressure seat and the upper pressure seat are closed, they form a surface contact and press-fit fixation to the variable diameter conical ring.

[0010] Preferably, the corrugated clamping assembly includes a second upright fixed to the upper end of the base, a lower corrugated clamping seat fixed to the upper end of the second upright, an upper corrugated clamping seat detachably fixed to the upper end of the lower corrugated clamping seat, and the inner clamping surfaces of the lower corrugated clamping seat and the upper corrugated clamping seat are both set as corrugated contour structures that perfectly match the outer corrugations of the corresponding corrugated pipe. After the mold is closed, the clamping surfaces fully fit the crests and troughs of the corrugated pipe.

[0011] Cooling components are also provided on the lower corrugated clamp and the upper corrugated clamp.

[0012] Preferably, the cooling and heat dissipation assembly includes a spiral cooling air duct formed in the lower corrugated clamp and the upper corrugated clamp, the lower corrugated clamp is fixedly connected to the air outlet of the spiral cooling air duct with an air outlet pipe, and the upper corrugated clamp is fixedly connected to the air inlet of the spiral cooling air duct with an air supply pipe.

[0013] A cooling shell, an induced draft fan, and a filter shell are sequentially installed on the air supply pipe. A mounting frame is fixed to the top of the upper corrugated clamping seat, and the cooling shell, induced draft fan, and filter shell are all fixed on the mounting frame.

[0014] A semiconductor refrigeration plate is embedded in the top of the cooling shell. The cold end of the semiconductor refrigeration plate is located inside the cooling shell, and the hot end is located outside the cooling shell. A temperature expansion plate is fixed on the cold end of the semiconductor refrigeration plate, and multiple temperature expansion columns are uniformly fixed at the lower end of the temperature expansion plate.

[0015] The rear side of the filter housing is provided with an opening, and a filter screen is fixed in the corresponding opening.

[0016] Preferably, the annular welding assembly includes a third upright fixed to the upper end of the base, a support ring fixed to the upper end of the third upright, a rotating ring slidably connected to the inner wall of the support ring via a slide rail, a driven gear fixedly sleeved on the outer wall of the rotating ring, a servo motor fixed to the inner wall of the support ring, a driving gear meshing with the driven gear fixed to the output end of the servo motor, and a welding head fixed to the inner wall of the rotating ring.

[0017] The servo motors of the two ring welding components are synchronously controlled, so that the two rotating rings rotate at the same angular velocity, thereby achieving synchronous welding of the two ring seams.

[0018] Preferably, the grinding and hammering integrated assembly is fixed to the inner wall of the rotating ring and is circumferentially offset from the welding head. It includes an insulating shell fixed to the inner wall of the rotating ring. The insulating shell has multiple push-pull rods movably inserted on the side away from the rotating ring. A grinding block is fixed to one end of the multiple push-pull rods located outside the insulating shell. A push-pull plate is fixed to one end of the multiple push-pull rods located inside the insulating shell.

[0019] Multiple return springs sleeved on the outside of the push-pull rod are fixed between the push-pull plate and the insulating shell. A permanent magnet plate is fixed on the side of the push-pull plate away from the push-pull rod. An electromagnetic plate is fixed on the inner wall of the insulating shell opposite to the permanent magnet plate.

[0020] By changing the type and magnitude of the current supplied to the electromagnetic plate, one can switch between grinding mode, light hammering mode during welding, and heavy hammering mode after welding.

[0021] Preferably, the cleaning assembly includes a cleaning pipe fixed to the inner wall of the rotating ring, a plurality of cleaning nozzles facing the weld are fixedly connected to the side wall of the cleaning pipe, and a connecting pipe is fixedly connected to the wall of the cleaning pipe. An air pump is installed on the connecting pipe and the air pump is fixed to the inner wall of the rotating ring.

[0022] Compared with existing technologies, the present invention has the following advantages:

[0023] 1. This invention uses three coaxially integrated positioning rods to achieve precise internal positioning of the variable diameter tapered ring and two bellows sections in a single clamping. Combined with two annular welding components that are synchronously welded at the same angular velocity, it effectively eliminates secondary clamping errors. Furthermore, synchronous welding ensures that the variable diameter tapered ring undergoes only one symmetrical thermal cycle, avoiding secondary thermal shock from sequential welding and reducing cumulative thermal damage.

[0024] 2. This invention utilizes a corrugated clamping assembly with a contoured clamping surface that perfectly matches the outer corrugations of the corrugated pipe. This surface contact replaces the traditional point / line contact, reducing the clamping pressure per unit area by more than 80%. This effectively avoids the problems of crumbling of the thin-walled corrugated pipe and stress concentration caused by using traditional clamps. At the same time, the corrugated groove is embedded to achieve bidirectional positioning in both the axial and circumferential directions, preventing movement and rotation during welding and ensuring a stable weld gap. Combined with a cooling and heat dissipation assembly, it can effectively eliminate the thermal stress generated on the corrugated pipe during welding, ensuring the service life and quality of the corrugated pipe in the future.

[0025] 3. This invention utilizes an integrated grinding and hammering component, which achieves tool-free switching between grinding and hammering via electromagnetic drive. Before welding, automatic grinding removes oxide film and oil stains, while a cleaning component removes dust. The two-stage hammering addresses defects at different stages: during welding, low-intensity hammering matches the optimal plasticity window of 500-800℃ to offset solidification shrinkage stress and prevent solidification cracks in thin-walled welds; after welding, high-intensity hammering eliminates 60-80% of residual tensile stress and introduces surface compressive stress, significantly improving the fatigue resistance and stress corrosion resistance of the weld. Attached Figure Description

[0026] Figure 1 This is a three-dimensional structural schematic diagram of the present invention;

[0027] Figure 2 This is a three-dimensional structural schematic diagram of the positioning support component of the present invention;

[0028] Figure 3 This is a three-dimensional cross-sectional view of the external pressure component of the present invention;

[0029] Figure 4 This is a three-dimensional structural schematic diagram of the corrugated compression assembly of the present invention;

[0030] Figure 5 This is a front cross-sectional view of the cooling and heat dissipation component of the present invention;

[0031] Figure 6 This is a front sectional view of the annular welding assembly of the present invention;

[0032] Figure 7 yes Figure 6 Enlarged view of section A;

[0033] Figure 8 This is a front cross-sectional view of the grinding and hammering integrated assembly of the present invention;

[0034] Figure 9 This is a schematic diagram of the structure of the blowing component of the present invention.

[0035] In the diagram: 1. Base; 2. Positioning support assembly; 21. Positioning rod; 22. First positioning section; 23. Second positioning section; 24. Third positioning section; 25. Fixed seat; 26. Support rod; 27. Connecting frame; 28. Connecting block; 3. Variable diameter conical ring; 4. Large diameter bellows; 5. Small diameter bellows; 6. External pressure assembly; 61. First upright; 62. Lower pressure seat; 63. Upper pressure seat; 7. Corrugated pressing assembly; 71. Second upright; 72. Lower corrugated clamping seat; 73. Upper corrugated clamping seat; 74. Cooling assembly; 741. Spiral cooling duct; 742. Air outlet; 743. Air supply duct; 744. Cooling shell; 745. Exhaust fan. 746. Filter housing; 747. Mounting bracket; 748. Semiconductor cooling plate; 749. Temperature expansion plate; 7410. Temperature expansion column; 7411. Filter screen; 8. Annular welding assembly; 81. Third upright; 82. Support ring; 83. Slide rail; 84. Rotating ring; 85. Driven gear; 86. Servo motor; 87. Drive gear; 88. Welding head; 9. Grinding and hammering integrated assembly; 91. Insulating shell; 92. Push-pull rod; 93. Grinding block; 94. Push-pull plate; 95. Return spring; 96. Permanent magnet plate; 97. Electromagnetic plate; 10. Cleaning assembly; 101. Cleaning pipe; 102. Cleaning nozzle; 103. Connecting pipe; 104. Air pump.

[0036] The technical solution of the present invention will now be clearly and completely described in conjunction with the accompanying drawings. Detailed Implementation

[0037] like Figures 1-9 As shown, an auxiliary welding device for automotive parts is used for the automated welding of variable diameter flexible joints in automotive exhaust systems. The variable diameter flexible joint is formed by sequentially butt-welding a large-diameter bellows 4, a variable diameter conical ring 3, and a small-diameter bellows 5. The entire device is based on a base 1 and integrates a positioning support assembly 2, an external pressure assembly 6, a bellows pressing assembly 7, a ring welding assembly 8, a grinding and hammering integrated assembly 9, and a cleaning assembly 10. The entire process of pre-welding treatment, synchronous welding, and post-weld stress relief is completed in one clamping.

[0038] like Figures 1-2 As shown, further, in this embodiment, the positioning support assembly 2 includes a positioning rod 21. The middle part of the positioning rod 21 is configured as a first positioning section 22 that matches the inner conical surface of the variable diameter conical ring 3. The two sections of the positioning rod 21 corresponding to the first positioning section 22 are respectively configured as a second positioning section 23 and a third positioning section 24 that match the inner diameters of the large-diameter corrugated pipe 4 and the small-diameter corrugated pipe 5. The outer surface of the first positioning section 22 is a conical surface, and the taper is completely matched with the inner conical surface of the variable diameter conical ring 3 to be welded. The outer diameter of the second positioning section 23 is clearance-fitted with the inner diameter of the large-diameter corrugated pipe 4. The outer diameter of the third positioning section 24 is clearance-fitted with the inner diameter of the small-diameter corrugated pipe 5.

[0039] The upper end of the base 1 is detachably fixed with two symmetrically arranged fixing seats 25 by bolts. The upper end of the fixing seat 25 is fixed with a support rod 26, and the upper end of the support rod 26 is fixed with a connecting frame 27. Both ends of the positioning rod 21 are fixed with connecting blocks 28 inserted into the connecting frame 27. The connecting blocks 28 and the connecting frame 27 are detachably fixed by bolts.

[0040] In actual use, the variable diameter conical ring 3 is first inserted from one end of the positioning rod 21 and pushed along the rod to the first positioning section 22. The inner conical surface of the variable diameter conical ring 3 is completely fitted with the conical surface of the first positioning section 22. Utilizing the automatic centering characteristic of the conical surface, the variable diameter conical ring 3 and the positioning rod 21 are automatically positioned coaxially. Then, the large diameter bellows 4 and the small diameter bellows 5 are inserted from both ends in sequence and fitted onto the second positioning section 23 and the third positioning section 24, respectively, to complete the pre-assembly of the workpiece. The pre-assembled positioning rod 21 is then passed through the center of the two annular welding components 8. The connecting blocks 28 at both ends are snapped into the corresponding connecting frames 27 and the bolts are tightened. The fixing seat 25 is then fixed to the base 1, completing the positioning of the entire workpiece.

[0041] The three positioning sections are coaxially integrated on a single positioning rod 21, achieving coaxial constraint between the variable diameter conical ring 3 and the two bellows sections from the inside in one go. The first positioning section 22 adopts a conical surface matching design, which, compared with cylindrical surface positioning, can automatically compensate for the inner diameter tolerance of the variable diameter conical ring 3, always maintaining surface contact and centering, and avoiding uneven circumferential gaps in the ring seam caused by the misalignment of the variable diameter conical ring 3. The positioning rod 21 is detachable as a whole, and the corresponding size positioning rod 21 can be quickly replaced according to different specifications of variable diameter flexible joints, adapting to flexible production of multiple varieties. It solves the problem that it is difficult to ensure coaxiality of the three sections with different diameters in the variable diameter structure.

[0042] like Figure 1 and Figure 3 As shown, further, in this embodiment, the external pressure assembly 6 includes a first upright 61 fixed to the upper end of the base 1, a lower pressure seat 62 fixed to the upper end of the first upright 61, and an upper pressure seat 63 detachably fixed to the upper end of the lower pressure seat 62. The inner clamping surfaces of the lower pressure seat 62 and the upper pressure seat 63 are both set as conical surfaces that match the outer conical surface of the variable diameter conical ring 3. After the lower pressure seat 62 and the upper pressure seat 63 are molded, they form a surface contact pressing and fixing of the variable diameter conical ring 3.

[0043] In actual use, after the positioning rod 21 is placed in place, the variable diameter tapered ring 3 naturally falls into the tapered groove of the lower pressure seat 62, and the upper pressure seat 63 is engaged and the fastener is locked. The upper and lower tapered clamping surfaces clamp the variable diameter tapered ring 3 together. Due to the wedge-shaped self-locking effect of the tapered surface, the clamping force will generate a radial component force, so that the variable diameter tapered ring 3 is firmly fixed, and at the same time, circumferential and axial limiting are achieved.

[0044] The conical contour clamping achieves surface contact clamping, replacing the line contact of the traditional V-block. The clamping force is evenly distributed on the entire outer surface of the variable diameter conical ring 3, reducing the pressure per unit area by more than 70%, avoiding local pressure deformation of the thin-walled variable diameter conical ring 3. At the same time, the clamping friction is greatly improved, preventing the variable diameter conical ring 3 from rotating circumferentially during welding. The conical clamping has an automatic centering and correction effect, which can automatically correct the slight deviation of the variable diameter conical ring 3 during mold closing. It cooperates with the inner positioning of the positioning rod 21 to further improve the coaxial accuracy.

[0045] like Figure 1 and Figure 4 As shown, further, in this embodiment, the corrugated pressing assembly 7 includes a second upright 71 fixed to the upper end of the base 1. A lower corrugated clamping seat 72 is fixed to the upper end of the second upright 71. An upper corrugated clamping seat 73 is detachably fixed to the upper end of the lower corrugated clamping seat 72. The inner clamping surfaces of the lower corrugated clamping seat 72 and the upper corrugated clamping seat 73 are both set as corrugated contour structures that completely match the outer corrugations of the corresponding corrugated pipe. After the mold is closed, the clamping surfaces fully fit the crests and troughs of the corrugated pipe.

[0046] In actual use, after the large-diameter corrugated pipe 4 and the small-diameter corrugated pipe 5 are fitted into the positioning rod 21, their corrugated sections naturally embed into the contour groove of the lower corrugated clamping seat 72. The upper corrugated clamping seat 73 is then engaged and locked, ensuring that each corrugation of the corrugated pipe is enclosed in the corresponding contour groove, achieving full corrugated surface contact clamping. During the welding process, the axial contraction force and circumferential rotational force of the corrugated pipe are evenly distributed and borne by the contour groove.

[0047] Corrugated contour clamping transforms traditional point contact at the corrugation crest into full corrugated surface contact, reducing clamping pressure per unit area by more than 80%. This effectively solves the problem of corrugation crests being crushed and stress concentration occurring in thin-walled corrugated pipes of 0.2–0.3 mm. After the corrugations are embedded in the contour groove, they simultaneously achieve bidirectional positioning in both the axial and circumferential directions, preventing axial movement and circumferential torsion of the corrugated pipe caused by welding thermal stress. This ensures the stability of the weld gap throughout the entire process and avoids burn-through or incomplete fusion caused by gap changes.

[0048] like Figure 1 , Figure 4 and Figure 5 As shown, further, in this embodiment, the lower corrugated clamping seat 72 and the upper corrugated clamping seat 73 are also provided with a cooling and heat dissipation assembly 74. The cooling and heat dissipation assembly 74 includes a spiral cooling air duct 741 formed in the lower corrugated clamping seat 72 and the upper corrugated clamping seat 73. The spiral cooling air duct 741 extends spirally along the axial direction of the lower corrugated clamping seat 72 and the upper corrugated clamping seat 73, completely covering the entire clamping area. The lower corrugated clamping seat 72 is fixedly connected to the air outlet of the spiral cooling air duct 741 with an air outlet pipe 742, and the upper corrugated clamping seat 73 is fixedly connected to the air inlet of the spiral cooling air duct 741 with an air supply pipe 743.

[0049] A cooling shell 744, an induced draft fan 745, and a filter shell 746 are sequentially installed on the air supply duct 743. A mounting bracket 747 is fixed to the top of the upper corrugated clamping seat 73, and the cooling shell 744, induced draft fan 745, and filter shell 746 are all fixed on the mounting bracket 747. A semiconductor cooling plate 748 is embedded in the top of the cooling shell 744. The cold end of the semiconductor cooling plate 748 is located inside the cooling shell 744, and the hot end is located outside the cooling shell 744. A heat expansion plate 749 is fixed on the cold end of the semiconductor cooling plate 748. Multiple heat expansion columns 7410 are fixed on the lower side of the heat expansion plate 749, extending into the airflow channel to significantly increase the heat exchange area. The rear side of the filter shell 746 is provided with an air inlet, and a filter screen 7411 is fixed in the corresponding opening to filter dust and impurities in the air.

[0050] In actual use, the induced draft fan 745 is started simultaneously during the welding process. Outside air enters the air supply duct 743 after being filtered by the filter screen 7411. When the airflow flows through the cooling shell 744, the cooling capacity of the semiconductor cooling plate 748 is fully transferred to the airflow through the heat expansion plate 749 and the heat expansion column 7410, cooling the air to 10-20°C. The low-temperature cold air enters the spiral cooling duct 741 and flows slowly along the spiral path, fully exchanging heat with the lower corrugated clamp 72 and the upper corrugated clamp 73, continuously carrying away the welding heat conducted to the lower corrugated clamp 72 and the upper corrugated clamp 73. The hot air after heat exchange is discharged from the air outlet duct 742. By adjusting the power of the semiconductor cooling plate 748 and the airflow of the induced draft fan 745, the temperature of the lower corrugated clamp 72 and the upper corrugated clamp 73 can be precisely controlled, keeping the temperature of the corrugated pipe clamping area within a safe range and avoiding the impact of high heat on the corrugated pipe.

[0051] The design of the spiral cooling duct 741 significantly extends the flow path and residence time of cold air within the lower corrugated clamp 72 and upper corrugated clamp 73, increasing heat exchange efficiency by more than 40% compared to straight ducts, resulting in more uniform cooling and avoiding additional stress caused by localized temperature differences. The active temperature control method, employing both semiconductor refrigeration and forced air cooling, allows for continuous adjustment of cooling capacity and precise temperature control within the clamping area, better preserving the work-hardening elasticity of the corrugated tube and preventing softening and stiffness reduction. The structure of the expansion plate 749 and expansion column 7410 expands the planar cold end of the semiconductor refrigeration plate 748 into a three-dimensional heat exchange structure, increasing the heat exchange area by more than five times and significantly improving cooling efficiency, ensuring stable low temperatures even under high heat input. The intake filter prevents dust from clogging the duct and also prevents dust-laden airflow from blowing towards the weld area, causing welding defects.

[0052] like Figure 1 , Figure 6 and Figure 7As shown, further, in this embodiment, the annular welding assembly 8 is provided in two sets, corresponding to the large-diameter end annular seam and the small-diameter end annular seam respectively. Each set includes a third upright 81 fixed to the upper end of the base 1, a support ring 82 fixed to the upper end of the third upright 81, a rotating ring 84 slidably connected to the inner wall of the support ring 82 through a slide rail 83, a driven gear 85 fixedly sleeved on the outer wall of the rotating ring 84, a servo motor 86 fixed to the inner wall of the support ring 82, a driving gear 87 meshing with the driven gear 85 fixed to the output end of the servo motor 86, and a welding head 88 fixed to the inner wall of the rotating ring 84, with the nozzle of the welding head 88 facing the center of the annular seam; the servo motors 86 of the two sets of annular welding assemblies 8 are connected to the same control system to achieve synchronous drive, so that the two rotating rings 84 rotate at the same angular velocity, realizing synchronous welding of the two annular seams.

[0053] In actual use, the two servo motors 86 receive control signals synchronously and start at the same speed. Through gear transmission, they drive the two rotating rings 84 to rotate at the same angular velocity. The two welding heads 88 start arc synchronously and move along their respective circumferential seams. Finally, the two circumferential seams start arc simultaneously and complete welding at the same time.

[0054] The two circumferential seams solidify and shrink simultaneously, with the shrinkage force acting symmetrically on both sides of the variable diameter conical ring 3. The variable diameter conical ring 3 solidifies in dynamic force balance, and the axial offset is reduced from 1-3mm in traditional sequential welding to within 0.2mm, ensuring that the corrugation spacing of the bellows at both ends is uniform and consistent, avoiding the deviation of the bellows preload from the design value due to the offset of the variable diameter conical ring 3. There is no need to flip the workpiece for secondary clamping, eliminating secondary positioning errors, and the coaxiality of the bellows at both ends is greatly improved. At the same time, the clamping auxiliary time is reduced, and the welding efficiency is increased by more than 40%. Synchronous welding allows the variable diameter conical ring 3 to undergo only one symmetrical thermal cycle, avoiding the problem of heat conduction from the first weld end causing overheating of the bellows at the second weld end when welding sequentially. The temperature field of the variable diameter conical ring 3 is uniform, and thermal deformation and cumulative thermal damage are significantly reduced.

[0055] like Figure 6 and Figure 8As shown, further, in this embodiment, the integrated grinding and hammering assembly 9 is fixed to the inner wall of the rotating ring 84 and arranged circumferentially offset from the welding head 88. It includes an insulating shell 91 fixed to the inner wall of the rotating ring 84. Multiple push-pull rods 92 are movably inserted on the side of the insulating shell 91 away from the rotating ring 84. A grinding block 93 is fixed to one end of the multiple push-pull rods 92 located outside the insulating shell 91. A push-pull plate 94 is fixed to one end of the multiple push-pull rods 92 located inside the insulating shell 91. Multiple return springs 95 are fixed between the push-pull plate 94 and the insulating shell 91 and are sleeved on the outside of the push-pull rods 92. A permanent magnet plate 96 is fixed to the side of the push-pull plate 94 away from the push-pull rods 92. An electromagnetic plate 97 is fixed to the inner wall of the insulating shell 91 and is arranged opposite to the permanent magnet plate 96. The working surface of the grinding block 93 is an arc surface that matches the outer curved surface of the circumferential seam. It is made of alumina abrasive or stainless steel wire, which takes into account both grinding and rust removal and hammering force transmission.

[0056] In actual use, by controlling the type and magnitude of the current supplied to the electromagnetic plate 97, seamless switching between three operating modes can be achieved:

[0057] Grinding mode: A positive constant current is passed through the electromagnetic plate 97, which generates a magnetism of the same name as the permanent magnet plate 96. The magnetic repulsion pushes the push-pull plate 94 to extend outward, compressing the reset spring 95, so that the grinding block 93 is pressed tightly against the weld surface with a set pressure; the rotating ring 84 rotates, causing the grinding block 93 to rotate around the weld once, completing the removal of oxide film and cleaning of oil stains in the weld and the areas on both sides;

[0058] Welding-assisted low-force hammering mode: A small current high-frequency alternating power supply is supplied to the electromagnetic plate 97. The magnetism of the electromagnetic plate 97 changes rapidly and alternately, generating magnetic repulsion and magnetic attraction. Combined with the elastic force of the return spring 95, it drives the push-pull plate 94 and the grinding block 93 to reciprocate at high speed, performing high-frequency low-force hammering on the newly solidified weld. The hammering force is controlled at 5-15N and the frequency is 20-50Hz. At this time, the grinding block 93 is located 30mm behind the welding head 88, and the corresponding weld temperature is exactly in the optimal plasticity range of 500-800℃.

[0059] Post-weld high-intensity hammering mode: After welding is completed, a high-current alternating power supply is applied, the magnetic force of the electromagnetic plate 97 is significantly enhanced, the hammering force is increased to 30-80N, and the rotating ring 84 continues to rotate 1-2 times to strengthen the hammering of the entire weld and the heat-affected zone on both sides.

[0060] The system allows for seamless switching between grinding and hammering functions without tool changes. Its compact structure accommodates the limited installation space of the ring welding assembly 8, reducing station switching time compared to split-type equipment. Constant-pressure automatic grinding replaces manual labor, ensuring consistent grinding force, trajectory, and range, resulting in stable oxide film removal. Combined with the cleaning assembly 10, dust is promptly removed. The low-force hammering during welding precisely matches the optimal plasticity temperature window of thin-walled welds, using minute plastic extension to offset solidification shrinkage stress, effectively preventing solidification cracks in 0.25mm-class thin-walled welds – a timeliness impossible with manual hammering. Post-weld high-force hammering further eliminates residual tensile stress, achieving an elimination rate of 60-80%, and introduces 100-200MPa of residual compressive stress into the weld surface, offsetting alternating tensile stress during operation and increasing the vibration fatigue life of the flexible joint by 2-3 times. For variable-diameter scenarios, hammering parameters can be set separately at both ends, with slightly higher hammering force at the larger diameter end and slightly lower at the smaller diameter end, matching different weld cross-sectional areas and ensuring consistent hammering energy per unit area.

[0061] like Figure 6 and Figure 9 As shown, further, in this embodiment, the cleaning assembly 10 includes a cleaning pipe 101 fixed to the inner wall of the rotating ring 84. The side wall of the cleaning pipe 101 is fixedly connected to a plurality of cleaning nozzles 102 facing the weld. The pipe wall of the cleaning pipe 101 is also fixedly connected to a connecting pipe 103. An air pump 104 is installed on the connecting pipe 103 and is fixed to the inner wall of the rotating ring 84.

[0062] In actual use, in grinding mode, the air pump 104 starts synchronously, and compressed air enters the cleaning pipe 101 through the connecting pipe 103. It is then sprayed out at high speed from multiple cleaning nozzles 102, closely following the grinding block 93 to promptly blow away the dust and debris generated during grinding from the weld area. As the rotating ring 84 rotates, it achieves full-circumference cleaning without dead angles. It can be selectively activated in welding and hammering modes to blow away welding fumes and hammering debris.

[0063] Simultaneous cleaning and blowing during grinding promptly removes grinding dust, preventing dust residue from forming pores and slag inclusions during welding. This is an essential component for ensuring the quality of automatic grinding. Multiple cleaning nozzles (102) cover the weld and the heat-affected zones on both sides, ensuring thorough cleaning. The cleaning position always closely follows the processing area, moving synchronously with the rotating ring (84), providing high timeliness.

[0064] The operation process in this embodiment is as follows: the variable diameter tapered ring 3, the large diameter bellows 4, and the small diameter bellows 5 are sequentially inserted into the first positioning section 22, the second positioning section 23, and the third positioning section 24 corresponding to the positioning rod 21 to complete the pre-assembly of the workpiece;

[0065] The positioning rod 21 of the pre-installed workpiece is passed through the center of the two annular welding components 8 and placed on the lower mold of the external pressure component 6 and the corrugated clamping component 7. The upper pressure seat 63 and the upper corrugated clamping seat 73 are fastened and locked. Then the connecting blocks 28 at both ends of the positioning rod 21 are locked and fixed to the connecting frame 27.

[0066] When the grinding mode is activated, the electromagnetic plate 97 is supplied with positive current, the grinding block 93 extends and presses the weld seam, the servo motor 86 drives the rotating ring 84 to rotate one revolution, and the grinding of the two ring seams is completed simultaneously. At the same time, the air pump 104 is activated, and the cleaning nozzle 102 follows the grinding block 93 to remove dust.

[0067] After grinding, the grinding block 93 retracts, the two welding heads 88 start arcing synchronously, and the two rotating rings 84 rotate synchronously at the same angular velocity to perform synchronous welding of the two circumferential seams; at the same time, the cooling and heat-reducing component 74 is activated to control the temperature of the clamping area of ​​the corrugated pressing component 7 within a safe range.

[0068] At the same time as welding starts, the grinding and hammering integrated component 9 switches to low-force hammering mode, closely following the welding head 88 to perform high-frequency low-force hammering on the newly solidified weld to eliminate solidification shrinkage stress.

[0069] After the two welds are completed simultaneously, the rotating ring 84 continues to rotate, switching to the high-intensity hammering mode, and then rotates 1 to 2 more times to strengthen the hammering of the welds and eliminate residual stress.

[0070] After hammering, release each clamping component in sequence, pull out the positioning rod 21, remove the welded variable diameter flexible joint, and conduct subsequent airtightness testing.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A welding auxiliary device for automotive parts, comprising a base (1), characterized in that, The upper end of the base (1) is detachably fixed with a positioning support assembly (2), and a variable diameter conical ring (3) to be welded is sleeved in the middle of the positioning support assembly (2). Large diameter corrugated pipes (4) and small diameter corrugated pipes (5) located at both ends of the variable diameter conical ring (3) are also symmetrically sleeved on the positioning support assembly (2). The upper end of the base (1) is fixed with an external pressure assembly (6) that is pressed against the outside of the variable diameter conical ring (3). The upper end of the base (1) is also symmetrically fixed with two corrugated pressing assemblies (7) that are respectively pressed against the outside of the large diameter corrugated pipe (4) and the small diameter corrugated pipe (5). The upper end of the base (1) is also symmetrically fixed with two annular welding assemblies (8) located at the welding points of the variable diameter conical ring (3) and the large diameter corrugated pipe (4), and the variable diameter conical ring (3) and the small diameter corrugated pipe (5). The moving end inside the annular welding assembly (8) is also fixed with a grinding and hammering integrated assembly (9) and a cleaning and blowing assembly (10). The positioning support assembly (2) includes a positioning rod (21). The middle part of the positioning rod (21) is set as a first positioning section (22) that matches the inner conical surface of the variable diameter conical ring (3). The two sections of the rod wall corresponding to the first positioning section (22) of the positioning rod (21) are respectively set as a second positioning section (23) and a third positioning section (24) that match the inner diameter of the large diameter corrugated pipe (4) and the small diameter corrugated pipe (5). The upper end of the base (1) is detachably fixed with two symmetrically arranged fixing seats (25) by bolts. The upper end of the fixing seat (25) is fixed with a support rod (26). The upper end of the support rod (26) is fixed with a connecting frame (27). Both ends of the positioning rod (21) are fixed with connecting blocks (28) inserted into the connecting frame (27). The connecting blocks (28) and the connecting frame (27) are detachably fixed by bolts. The corrugated clamping assembly (7) includes a second upright (71) fixed to the upper end of the base (1). A lower corrugated clamping seat (72) is fixed to the upper end of the second upright (71). An upper corrugated clamping seat (73) is detachably fixed to the upper end of the lower corrugated clamping seat (72). The inner clamping surfaces of the lower corrugated clamping seat (72) and the upper corrugated clamping seat (73) are both set as corrugated contour structures that are completely matched with the outer corrugations of the corresponding corrugated pipe. After the mold is closed, the clamping surfaces are fully in contact with the crests and troughs of the corrugated pipe. Cooling components (74) are also provided on the lower corrugated clamp (72) and the upper corrugated clamp (73). The annular welding assembly (8) includes a third upright (81) fixed to the upper end of the base (1), a support ring (82) fixed to the upper end of the third upright (81), a rotating ring (84) slidably connected to the inner wall of the support ring (82) via a slide rail (83), a driven gear (85) fixedly sleeved on the outer wall of the rotating ring (84), a servo motor (86) fixed to the inner wall of the support ring (82), a drive gear (87) meshing with the driven gear (85) fixed to the output end of the servo motor (86), and a welding head (88) fixed to the inner wall of the rotating ring (84). The servo motors (86) of the two ring welding assemblies (8) are synchronously controlled to make the two rotating rings (84) rotate at the same angular velocity, thereby achieving synchronous welding of the two ring seams.

2. The automotive parts welding auxiliary device according to claim 1, characterized in that, The external pressure assembly (6) includes a first upright (61) fixed to the upper end of the base (1). A lower pressure seat (62) is fixed to the upper end of the first upright (61). An upper pressure seat (63) is detachably fixed to the upper end of the lower pressure seat (62). The inner clamping surfaces of the lower pressure seat (62) and the upper pressure seat (63) are both set as conical surfaces that match the outer conical surface of the variable diameter conical ring (3). After the lower pressure seat (62) and the upper pressure seat (63) are molded, they form a surface contact and press-fit fixation on the variable diameter conical ring (3).

3. The automotive parts welding auxiliary device according to claim 1, characterized in that, The cooling and heat dissipation assembly (74) includes a spiral cooling air duct (741) formed in the lower corrugated clamp (72) and the upper corrugated clamp (73). The lower corrugated clamp (72) is fixedly connected to the air outlet of the spiral cooling air duct (741) with an air outlet pipe (742), and the upper corrugated clamp (73) is fixedly connected to the air inlet of the spiral cooling air duct (741) with an air supply pipe (743). The air supply pipe (743) is sequentially equipped with a cooling shell (744), an exhaust fan (745) and a filter shell (746). The top of the upper corrugated clamp (73) is fixed with a mounting bracket (747). The cooling shell (744), the exhaust fan (745) and the filter shell (746) are all fixed on the mounting bracket (747). The top of the cooling shell (744) is fitted with a semiconductor refrigeration plate (748). The cold end of the semiconductor refrigeration plate (748) is located inside the cooling shell (744), and the hot end is located outside the cooling shell (744). A heat expansion plate (749) is fixed on the cold end of the semiconductor refrigeration plate (748), and multiple heat expansion columns (7410) are uniformly fixed at the lower end of the heat expansion plate (749). The rear side of the filter housing (746) is provided with an opening, and a filter screen (7411) is fixed in the corresponding opening.

4. The automotive parts welding auxiliary device according to claim 1, characterized in that, The grinding and hammering integrated assembly (9) is fixed to the inner wall of the rotating ring (84) and is circumferentially offset from the welding head (88). It includes an insulating shell (91) fixed to the inner wall of the rotating ring (84). Multiple push-pull rods (92) are movably inserted on the side of the insulating shell (91) away from the rotating ring (84). A grinding block (93) is fixed to one end of the multiple push-pull rods (92) located outside the insulating shell (91). A push-pull plate (94) is fixed to one end of the multiple push-pull rods (92) located inside the insulating shell (91). Multiple return springs (95) sleeved on the outside of the push-pull rod (92) are fixed between the push-pull plate (94) and the insulating shell (91). A permanent magnet plate (96) is fixed on the side of the push-pull plate (94) away from the push-pull rod (92). An electromagnetic plate (97) is fixed on the inner wall of the insulating shell (91) opposite to the permanent magnet plate (96). By changing the type and magnitude of the current supplied to the electromagnetic plate (97), one can switch between grinding mode, light hammering mode during welding, and heavy hammering mode after welding.

5. The automotive parts welding auxiliary device according to claim 1, characterized in that, The cleaning assembly (10) includes a cleaning pipe (101) fixed to the inner wall of the rotating ring (84). The side wall of the cleaning pipe (101) is fixedly connected to a plurality of cleaning nozzles (102) facing the weld. The pipe wall of the cleaning pipe (101) is also fixedly connected to a connecting pipe (103). An air pump (104) is installed on the connecting pipe (103). The air pump (104) is fixed to the inner wall of the rotating ring (84).

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