Arc welding apparatus for positioning of aluminum products
By setting an annular retaining groove and an internal expansion clamping assembly in the middle of the mandrel, the problem of insufficient support or jamming caused by axial movement and thermal expansion of the copper liner ring during the butt arc welding of thin-walled aluminum tubes is solved, achieving stable support and smooth extraction at the weld root, and solving the problems of concave defects and jamming at the weld root.
Patent Information
- Application Number
- CN202611228423.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-13
- Publication Date
- 2026-11-03
AI Technical Summary
During the butt welding of thin-walled aluminum tubes, the copper gasket ring may move axially due to gravity eccentricity and welding vibration, losing its inner support for the weld root and causing concave defects at the weld root. At the same time, the gap between the copper gasket ring and the inner wall of the pipe may be too large or too small, resulting in insufficient support or jamming.
A ring-shaped retaining ring is embedded in the middle of the mandrel. Combined with the internal expansion clamping assembly and the rotary drive assembly, the axial movement of the copper liner ring is restricted by the C-shaped retaining ring and the internal expansion clamping assembly, ensuring its rigid support inside the mating seam area. The thermal expansion of the copper liner ring is reduced by the heat dissipation groove.
The copper gasket ring remains within the butt joint area during welding, providing stable inner support, avoiding defects at the weld root, and can be installed before welding and removed after welding without getting stuck in the pipe cavity, thus reducing the impact of thermal expansion.
Smart Images
Figure CN123024958A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of welding equipment technology, and more specifically, to a positioning arc welding device for aluminum product processing. Background Technology
[0002] In the butt welding of thin-walled aluminum tubes, a copper gasket ring is usually placed inside the tube to provide rigid support for the root of the weld. The mandrel drives the tube to rotate to achieve continuous arc welding of the annular butt joint.
[0003] In the prior art, the copper liner ring is fitted onto the mandrel with a clearance fit, allowing it to slide freely along the mandrel's axial direction without any axial restraint. When the mandrel rotates, the copper liner ring tends to move axially due to its own weight and eccentricity. Vibrations caused by the welding arc are transmitted through the pipe fittings to the copper liner ring, further exacerbating this movement.
[0004] The above structure has the following defects: the copper gasket ring loses its inner support for the weld root after deviating axially from the butt joint area, resulting in an inward concave defect at the weld root; the radial gap between the copper gasket ring and the inner wall of the pipe is not constrained. When the gap is too large, the copper gasket ring is insufficient to support the softened pipe wall due to heat, and the pipe wall collapses inward. When the gap is too small, the copper gasket ring expands due to heat and forms an interference fit with the inner wall of the pipe. After welding, the copper gasket ring gets stuck in the inner cavity of the pipe and cannot be pulled out. Summary of the Invention
[0005] This invention provides a positioning arc welding device for aluminum product processing, which solves the technical problems of concave defects at the root of the weld and jamming of the copper gasket ring during the butt arc welding of thin-walled aluminum tubes.
[0006] This invention discloses a positioning arc welding device for aluminum product processing, comprising a frame, a mandrel, a copper liner ring, a pair of C-shaped retaining rings, two sets of internal expansion clamping assemblies, a rotary drive assembly, and a welding torch holder. The frame is a portal frame structure, with bearing seats installed at the top of each of the two side columns. The mandrel is supported at both ends by bearings within the bearing seats, and two annular retaining ring grooves spaced axially on the outer circular surface of the mandrel's middle section. The copper liner ring is fitted into the section between the two retaining ring grooves in the middle of the mandrel, with its inner hole clearance-fitting the outer circular surface of the mandrel, and its outer circular surface adjacent to the inner wall surface of the butt joint area of the thin-walled aluminum tube. A pair of C-shaped retaining rings are respectively embedded in the two retaining ring grooves, with the radial outer edge of each C-shaped retaining ring protruding from the outer circular surface of the mandrel to form an axial shoulder. The two C-shaped retaining rings abut against the two axial end faces of the copper liner ring, confining the copper liner ring within the axial range between the two retaining ring grooves from both axial sides. Two sets of internal expansion clamping assemblies are respectively fitted onto the two ends of the mandrel and symmetrically distributed on both sides of the copper liner ring. Each set of internal expansion clamping assemblies includes an elastic support body, which expands radially after axial compression and fits tightly against the inner wall of the thin-walled aluminum tube. A rotary drive assembly is mounted on the frame and connected to one end of the mandrel, driving the mandrel to rotate around its own axis. The welding torch holder is fixed to the crossbeam of the frame and extends towards the area where the copper liner ring is located. A welding torch clamp is installed at the end of the welding torch holder.
[0007] Furthermore, each end section of the mandrel has an external thread segment on its outer circumferential surface, with each external thread segment located on the side of the corresponding internal expansion clamping assembly away from the copper liner ring. Each set of internal expansion clamping assemblies includes a rubber drum ring, two metal pressure rings, and a locking nut. The rubber drum ring is a ring-shaped elastic body, fitted onto the outer circumferential surface of the mandrel as an elastic support. The two metal pressure rings are respectively fitted onto the mandrel and abut against the two axial end faces of the rubber drum ring, with the inner holes of the metal pressure rings clearance-fitted to the outer circumferential surface of the mandrel. The locking nut is screwed onto the corresponding external thread segment and forms a helical pair with the mandrel. When the locking nut is pushed axially toward the rubber drum ring, the end face of the locking nut abuts against the metal pressure ring on the side away from the copper liner ring, pushing the metal pressure ring to compress the rubber drum ring axially. The metal pressure ring closer to the copper liner ring is axially stopped by the radial outer edge of the corresponding C-shaped retaining spring. Two metal pressure rings clamp the rubber drum ring from both sides of the axial direction. After being compressed axially, the rubber drum ring expands radially and uniformly. The outer circular surface of the rubber drum ring is in close contact with the inner wall of the thin-walled aluminum tube. The friction between the outer circular surface of the rubber drum ring and the inner wall of the thin-walled aluminum tube causes the thin-walled aluminum tube to rotate synchronously around the axis with the mandrel.
[0008] Furthermore, the radial outer edge of each C-shaped retainer ring near the side of the internal expansion clamping assembly abuts against the corresponding axial end face of the copper liner ring on one side along the axial direction, and the radial outer edge abuts against the end face of the metal pressure ring near the side of the copper liner ring on the other side along the axial direction.
[0009] Furthermore, the axial width of the copper gasket ring covers the area where the joint between the two thin-walled aluminum tubes is located. A unilateral radial clearance is maintained between the outer diameter of the copper gasket ring and the inner diameter of the thin-walled aluminum tube. ,in It is the radial distance between the outer surface of the copper gasket ring and the inner wall of the thin-walled aluminum tube on one side. The value ranges from 0.3 mm to 0.8 mm.
[0010] Furthermore, several heat dissipation grooves are formed on the outer circular surface of the copper liner ring along the axial direction. Each heat dissipation groove is evenly distributed along the circumference of the copper liner ring, and each heat dissipation groove extends axially and penetrates to the two axial end faces of the copper liner ring.
[0011] Furthermore, the heat dissipation groove is a long, narrow groove, and the depth of the heat dissipation groove is less than one-third of the wall thickness of the copper liner ring.
[0012] Furthermore, the rotary drive assembly includes a worm gear, a worm, a worm bearing housing, and a geared motor. The worm gear is fixed to the end of the mandrel extending out of the bearing housing via a key connection, and rotates synchronously with the mandrel. The worm is mounted on a column on one side of the frame via a worm bearing housing, with the worm's axis perpendicular to the mandrel's axis. The worm and worm gear mesh to form a worm gear transmission pair. The geared motor is fixed to a column on one side of the frame and connected to one end of the worm. The geared motor drives the worm to rotate around its own axis, and the worm, via the worm gear, drives the mandrel to rotate uniformly around its own axis.
[0013] Furthermore, the welding torch holder is an L-shaped bracket. The vertical section of the welding torch holder is fixed to the middle of the crossbeam of the frame with bolts, and the horizontal section of the welding torch holder extends towards the area where the copper liner ring is located. The welding torch clamp is installed at the end of the horizontal section of the welding torch holder, and the welding torch is clamped in the welding torch clamp. The nozzle of the welding torch points vertically downward and is aligned with the highest point of the butt joint of the thin-walled aluminum tube. The welding torch remains fixed as the thin-walled aluminum tube rotates around its axis.
[0014] Furthermore, each C-shaped retaining ring is an open elastic ring. After radial compression, the C-shaped retaining ring is embedded in the corresponding retaining ring groove. The C-shaped retaining ring expands radially and clamps itself in the retaining ring groove by its own elastic restoring force. When the copper liner ring tends to move axially, the end face of the copper liner ring makes surface contact with the radial outer edge of the corresponding C-shaped retaining ring to stop it. The C-shaped retaining ring transmits the axial force to the groove wall of the retaining ring groove, which is borne by the mandrel as a whole.
[0015] Furthermore, the frame is a portal frame structure, including two side columns and a crossbeam connected to the top of the two side columns. The bearing housing is fixedly installed on the top of the two side columns, and the axis of the spindle extends horizontally.
[0016] This invention solves the technical problem of axial movement and deviation of the copper gasket ring due to gravity eccentricity and welding vibration, leading to loss of inner support at the weld root, by creating two annular retaining ring grooves in the middle of the mandrel and embedding C-shaped retaining rings. The radial outer edges of the two C-shaped retaining rings form surface contact stops on both sides of the axial direction, thus providing a stop for the copper gasket ring. This achieves the technical effect of keeping the copper gasket ring continuously within the corresponding axial range of the butt joint throughout the welding process, and providing stable inner rigid support at the weld root. The invention also addresses the issue of unilateral radial gap between the outer diameter of the copper gasket ring and the inner diameter of the pipe fitting. By limiting the gap to within the range of 0.3 mm to 0.8 mm, the technical problems of excessive gap causing inward collapse of the pipe wall and insufficient gap causing the copper gasket ring to become stuck in the pipe cavity after thermal expansion are solved. This achieves the technical effect of allowing the copper gasket ring to be smoothly installed before welding and easily removed after welding, while providing effective radial support for the softened pipe wall. The heat dissipation grooves evenly distributed circumferentially on the outer surface of the copper gasket ring increase the air gap area between the copper gasket ring and the inner wall of the pipe, reducing the peak temperature rise of the copper gasket ring and decreasing its radial thermal expansion, further ensuring that the copper gasket ring can be smoothly removed from the pipe cavity after welding. Attached Figure Description
[0017] Figure 1 This is a front view of the thin-walled aluminum tube butt welding aluminum product processing positioning arc welding device of the present invention;
[0018] Figure 2 This is a longitudinal sectional view of the thin-walled aluminum tube butt welding aluminum product processing positioning arc welding device of the present invention;
[0019] Figure 3 This is a cross-sectional view of the copper gasket ring at the processing positioning arc welding device for butt welding of thin-walled aluminum tubes according to the present invention.
[0020] Figure 4 This is an isometric view of the thin-walled aluminum tube butt welding aluminum product processing positioning arc welding device of the present invention;
[0021] Figure 5 This is a schematic diagram of the structure of the copper gasket ring of the present invention;
[0022] Figure 6 This is a schematic diagram of the structure of the rotary drive assembly of the present invention.
[0023] In the diagram: Frame-1; Mandrel-2; Bearing seat-3; Bearing-4; Rubber drum ring-5; Metal pressure ring-6; Locking nut-7; Copper liner ring-8; C-shaped snap ring-9; Worm gear-10; Worm-11; Worm bearing seat-12; Gear motor-13; Welding torch holder-14; Welding torch clamp-15; Welding torch-16; Thin-walled aluminum tube-17. Detailed Implementation
[0024] In the butt arc welding of thin-walled aluminum tubes (wall thickness to outer diameter ratio less than 1:100), two thin-walled aluminum tubes 17 are fitted onto the two ends of a mandrel 2. An internal expansion clamping assembly evenly tightens the tubes circumferentially from the inner wall surface, and the butt joint surfaces of the two tubes are aligned and fitted in the middle region of the mandrel 2. A copper gasket ring 8 is fitted in the middle of the mandrel 2, with its outer surface adjacent to the inner wall surface of the tube in the butt joint area, providing rigid inner support for the weld root. A rotation drive assembly drives the mandrel 2 to rotate uniformly around a horizontal axis, and the welding torch 16 continuously arc welds the annular butt joint at the highest point of the tube.
[0025] The copper gasket ring 8 is fitted onto the mandrel 2 with a clearance fit. During the rotation of the mandrel 2, the copper gasket ring 8 deviates from the axis periodically due to its own weight and eccentricity. In addition, the vibration caused by the welding arc acts on the pipe and is transmitted to the copper gasket ring 8. The copper gasket ring 8 moves axially on the mandrel 2 and deviates from the butt joint area, losing its inner support for the weld root, resulting in an inward concave defect at the weld root. At the same time, the radial clearance between the outer surface of the copper gasket ring 8 and the inner wall of the pipe is not constrained. When the clearance is too large, the copper gasket ring 8 provides insufficient support for the pipe wall, and the pipe wall collapses inward in the weld softening zone. When the clearance is too small, the welding heat input causes the copper gasket ring 8 to expand due to heat, and the outer surface of the copper gasket ring 8 forms an interference fit with the inner wall of the pipe. After welding, the copper gasket ring 8 is stuck in the inner cavity of the pipe and cannot be pulled out axially.
[0026] like Figure 1-6 As shown in the embodiment, according to the embodiment of this invention, this embodiment provides an aluminum product processing positioning arc welding device for butt arc welding of thin-walled aluminum tube 17, which includes at least a frame 1, a mandrel 2, two sets of internal expansion clamping assemblies, a copper liner ring 8, a pair of C-shaped retaining rings 9, a rotary drive assembly and a welding torch holder 14.
[0027] The frame 1 is a portal frame structure, including two side columns and a crossbeam connected to the top of the two side columns. Each side column has a bearing seat 3 fixedly installed at the top, and each bearing seat 3 contains a bearing 4.
[0028] The mandrel 2 is a cylindrical rod with an outer diameter smaller than the inner diameter of the thin-walled aluminum tube 17 to be welded. Both ends of the mandrel 2 are inserted into bearings 4 within the bearing seats 3 on both sides. The mandrel 2, through the bearings 4, forms a rotating pair with the frame 1, allowing it to rotate around its own axis. Two annular retaining grooves are formed on the outer circumferential surface of the central region of the mandrel 2. These grooves are spaced apart axially, and the axial distance between them matches the axial width of the copper liner ring 8. Each end section of the mandrel 2 has an external thread segment machined on its outer circumferential surface, with each thread segment located on the side of the corresponding internal expansion clamping assembly furthest from the copper liner ring 8.
[0029] Two sets of internal expansion clamping assemblies are respectively fitted onto the two end sections of the mandrel 2, symmetrically distributed on both sides of the copper liner ring 8. Each set of internal expansion clamping assemblies includes an elastic support body, which is fitted onto the outer circular surface of the mandrel 2. After being axially compressed, it expands uniformly in the radial direction. The outer circular surface of the elastic support body is in close contact with the inner wall surface of the thin-walled aluminum tube 17, and the tube and the mandrel 2 are connected as one unit by friction.
[0030] In some embodiments, each internal expansion clamping assembly includes a rubber drum ring 5, two metal pressure rings 6, and a locking nut 7. The rubber drum ring 5 is a ring-shaped elastic body, fitted onto the outer circumferential surface of the mandrel 2, serving as an elastic support body to provide radial expansion and support. The two metal pressure rings 6 are respectively fitted onto the mandrel 2 and abut against the two axial end faces of the rubber drum ring 5. The inner hole of the metal pressure ring 6 is clearance-fitted with the outer circumferential surface of the mandrel 2, allowing the metal pressure ring 6 to slide axially along the mandrel 2. The locking nut 7 is screwed onto the corresponding external thread section, forming a helical pair with the external thread section of the mandrel 2. Tightening the locking nut 7 causes it to advance axially toward the rubber drum ring 5, with the end face of the locking nut 7 abutting against the metal pressure ring 6 on the side away from the copper liner ring 8, pushing the metal pressure ring 6 axially toward the rubber drum ring 5. The metal pressure ring 6 on the side closer to the copper liner ring 8 is axially stopped by the radial outer edge of the corresponding C-shaped retaining spring 9 and does not move in the same direction as the compression force. Two metal pressure rings 6 clamp the rubber drum ring 5 from both axial sides. After being compressed axially, the rubber drum ring 5 elastically deforms, and its radial dimension increases uniformly. The outer circular surface of the rubber drum ring 5 is in close contact with the inner wall of the thin-walled aluminum tube 17. The friction between the outer circular surface of the rubber drum ring 5 and the inner wall of the tube transmits the rotational motion of the mandrel 2 to the tube, causing the tube to rotate synchronously around the axis with the mandrel 2.
[0031] The copper liner ring 8 is an annular copper sleeve fitted onto the section of the mandrel 2 located between the two sets of internal expansion clamping components. The inner hole of the copper liner ring 8 penetrates both axial end faces of the copper liner ring 8, and there is a clearance fit between the inner hole and the outer circular surface of the mandrel 2, allowing the copper liner ring 8 to slide axially along the outer circular surface of the mandrel 2. A single-sided radial clearance δ is maintained between the outer diameter of the copper liner ring 8 and the inner diameter of the thin-walled aluminum tube 17, where δ is the single-sided radial distance between the outer circular surface of the copper liner ring 8 and the inner wall surface of the tube. The value ranges from 0.3 mm to 0.8 mm. The axial width of the copper gasket ring 8 covers the area where the joint between the two pipe sections is located. The outer circular surface of the copper gasket ring 8 is close to the inner wall surface of the joint area of the pipe fitting, providing inner rigid support for the root of the weld.
[0032] A pair of C-shaped retaining rings 9 are respectively embedded in two annular retaining ring grooves in the middle of the mandrel 2. Each C-shaped retaining ring 9 is an open elastic ring that is radially compressed and inserted into the retaining ring groove during assembly. The C-shaped retaining ring 9 expands radially and clamps itself into the retaining ring groove by its own elastic restoring force. The radial outer edge of each C-shaped retaining ring 9 protrudes from the outer circular surface of the mandrel 2, forming a shoulder along the axial direction. The end faces of the two C-shaped retaining rings 9 facing the copper liner ring 8 are respectively opposite to the two axial end faces of the copper liner ring 8 and abut against the two axial end faces of the copper liner ring 8. The two C-shaped retaining rings 9 constrain the copper liner ring 8 from both axial sides within the axial range between the two retaining ring grooves. When the copper liner ring 8 tends to move axially due to gravity eccentricity or welding vibration during the rotation of the mandrel 2, the end face of the copper liner ring 8 makes surface contact with the radial outer edge of the corresponding C-shaped retaining ring 9 to stop it. The C-shaped retaining ring 9 transmits the axial force to the groove wall of the retaining ring groove, which is borne by the mandrel 2 as a whole. The axial displacement of the copper liner ring 8 is restricted to the range between the two retaining ring grooves.
[0033] It should be noted that the C-shaped retaining ring 9 on the side of the inner expansion clamping assembly in the two retaining ring grooves simultaneously performs two functions: axial limiting of the copper pad ring 8 and axial stopping of the metal pressure ring 6 on the side of the copper pad ring 8. The height of the radial outer edge of the C-shaped retaining ring 9 protruding from the outer circle of the spindle 2 on the side of the inner expansion clamping assembly must simultaneously meet the above two stopping requirements.
[0034] Furthermore, to reduce the radial dimension increase of the copper gasket ring 8 due to thermal expansion during welding, several heat dissipation grooves are formed axially on the outer circular surface of the copper gasket ring 8. Each heat dissipation groove is evenly distributed circumferentially along the copper gasket ring 8, extending axially, with both ends penetrating to the two axial end faces of the copper gasket ring 8. The heat dissipation grooves are formed within the solid outer circular surface of the copper gasket ring 8, appearing as elongated grooves, with a groove depth less than one-third of the wall thickness of the copper gasket ring 8. The heat dissipation grooves increase the air gap area between the outer circular surface of the copper gasket ring 8 and the inner wall of the pipe fitting. Welding heat is conducted through the copper gasket ring 8 to the groove wall and then dissipated into the air within the groove, reducing the peak temperature rise of the copper gasket ring 8 and decreasing its radial thermal expansion.
[0035] The rotary drive assembly is mounted on a column on one side of the frame 1 and connected to one end of the spindle 2, driving the spindle 2 to rotate at a constant speed around its own axis.
[0036] In some embodiments, the rotary drive assembly is a worm gear drive assembly. The worm gear 10 is fixed via a key to the end of the spindle 2 extending beyond the bearing housing 3 on the side where the rotary drive assembly is mounted. The worm gear 10 rotates synchronously with the spindle 2 around its axis. The worm 11 is mounted on a column on the side where the rotary drive assembly is mounted via a worm bearing housing 12. The axis of the worm 11 is perpendicular to the axis of the spindle 2, and the worm 11 can rotate around its own axis. The worm 11 and the worm gear 10 mesh to form a worm gear transmission pair, creating a cross-axis reduction transmission. One end of the worm 11 is connected to a geared motor 13, which is bolted to the outer surface of the column on the side where the rotary drive assembly is mounted. The power cable of the geared motor 13 is laid along the column surface to the bottom of the frame 1 for power supply. The geared motor 13 drives the worm 11 to rotate around its own axis. The meshing of the worm 11 and the worm gear 10 transmits the rotational motion to the worm gear 10, which, via a key connection, drives the spindle 2 to rotate uniformly around its own axis.
[0037] The welding torch holder 14 is an L-shaped support. The vertical section of the welding torch holder 14 is fixed to the middle of the crossbeam of the frame 1 with bolts. The horizontal section of the welding torch holder 14 extends from the crossbeam toward the area where the copper gasket ring 8 is located. A welding torch clamp 15 is installed at the end of the horizontal section of the welding torch holder 14. The welding torch 16 is clamped in the welding torch clamp 15, with the nozzle of the welding torch 16 pointing vertically toward the ground and aimed at the highest point of the pipe fitting joint. The welding torch 16 remains stationary as the pipe fitting rotates around its axis, continuously arc welding the pipe fitting joint that passes the highest point.
[0038] When using an aluminum product processing positioning arc welding device to perform butt arc welding of thin-walled aluminum tube 17, follow these steps.
[0039] Step 1: Assemble the copper liner ring 8 and C-shaped retaining ring 9: After radially compressing one C-shaped retaining ring 9, insert it into one of the two retaining ring grooves in the middle of the mandrel 2. The C-shaped retaining ring 9 expands radially and locks into the retaining ring groove due to its elastic restoring force, with its radial outer edge protruding from the outer surface of the mandrel 2. Slide the copper liner ring 8 from the end of the mandrel 2, and slide it along the outer surface of the mandrel 2 until it abuts against the end face of the already installed C-shaped retaining ring 9. Insert the other C-shaped retaining ring 9 into the other retaining ring groove. The two C-shaped retaining rings 9 abut against the end face of the copper liner ring 8 from both axial sides, and the copper liner ring 8 is positioned within the axial range between the two retaining ring grooves.
[0040] Step 2, Pipe insertion and alignment of mating ends: Pass the mandrel 2 through the inner cavity of the two thin-walled aluminum tubes 17, so that the two tubes are respectively fitted on the outer side of the two sets of internal expansion clamping components of the mandrel 2, and push the two tubes to move towards each other along the axial direction, so that the mating ends of the two tubes are aligned and fitted in the area corresponding to the outer circle of the copper liner ring 8.
[0041] Step 3, internal expansion clamping of pipe fittings: Apply axial compression force to the two sets of internal expansion clamping components. After being axially compressed, the elastic support body expands radially. The outer circular surface of the elastic support body is in close contact with the inner wall of the pipe fitting, and the pipe fitting is fixed to the mandrel 2 by friction.
[0042] In some embodiments, the specific operation of step three is as follows: tighten two sets of locking nuts 7 respectively, each locking nut 7 is pushed along the external thread section of the spindle 2 towards the rubber drum ring 5, pushing the outer metal pressure ring 6 to press the rubber drum ring 5 axially, the two metal pressure rings 6 clamp the rubber drum ring 5 from both sides of the axial direction, the rubber drum ring 5 expands radially uniformly after being axially compressed, and the outer circular surface of the rubber drum ring 5 is in close contact with the inner wall surface of the pipe fitting.
[0043] Step 4, install mandrel 2 to frame 1: place both ends of mandrel 2 into bearings 4 inside bearing seats 3 at the top of the two side columns, and the mandrel 2 is supported on frame 1 by bearings 4.
[0044] Step 5, Rotary Welding: The rotary drive assembly drives the mandrel 2 to rotate uniformly around its own axis, and the pipe fitting rotates synchronously around the axis with the mandrel 2. The welding torch 16 continuously performs arc welding on the butt joint at the highest point of the pipe fitting from a fixed position. During the rotation of the mandrel 2, the copper gasket ring 8 is held in the corresponding position in the butt joint area by the axial limiting action of the two C-shaped retaining rings 9, and the outer circular surface of the copper gasket ring 8 continuously provides inner rigid support for the root of the weld. After the pipe fitting rotates a full circle, the circumferential weld is closed.
[0045] Step 6, Disassembly: After welding, release the axial compressive force of the two sets of internal expansion clamping components. The elastic support body retracts radially under the action of elastic restoring force, releasing the pipe fitting. After removing a C-shaped retaining ring 9 from the end of the mandrel 2, pull the copper liner ring 8 axially out of the inner cavity of the pipe fitting.
[0046] In some embodiments, the specific operation of relieving the axial compressive force in step six is as follows: remove the two sets of locking nuts 7, and the rubber drum ring 5 retracts radially to a free state under the action of elastic restoring force, and the outer circular surface of the rubber drum ring 5 separates from the inner wall surface of the pipe fitting.
[0047] In this embodiment, two annular retaining ring grooves are formed on the outer circular surface of the central region of the mandrel 2. C-shaped retaining rings 9 are embedded in the two retaining ring grooves respectively. The radial outer edges of the two C-shaped retaining rings 9 protrude from the outer circular surface of the mandrel 2 and abut against the two axial end faces of the copper liner ring 8 respectively, forming a surface contact stop on the copper liner ring 8 from both axial sides. Therefore, the axial movement tendency of the copper liner ring 8 caused by gravity eccentricity and welding vibration during the rotation of the mandrel 2 is blocked by the two C-shaped retaining rings 9. The copper liner ring 8 always remains within the axial range between the two retaining ring grooves. This range corresponds to the butt joint area of the pipe fitting. The weld root continuously receives rigid support from the inner side of the outer circular surface of the copper liner ring 8 throughout the welding process, avoiding the concave defect of the weld root due to loss of support.
[0048] The radial clearance δ between the outer diameter of the copper gasket ring 8 and the inner diameter of the pipe fitting is between 0.3 mm and 0.8 mm. This clearance range allows the copper gasket ring 8 to slide freely axially into the inner cavity of the pipe fitting before welding for assembly. Simultaneously, during welding, the radial dimension of the copper gasket ring 8 increases due to thermal expansion, narrowing the clearance while still retaining a margin to prevent interference compression with the inner wall of the pipe fitting. After welding, the copper gasket ring 8 can still be smoothly extracted axially from the inner cavity of the pipe fitting. Furthermore, this clearance range ensures a sufficiently small distance between the outer surface of the copper gasket ring 8 and the softened pipe wall, allowing the copper gasket ring 8 to provide effective radial support for the softened pipe wall and prevent inward collapse.
[0049] Furthermore, the circumferentially distributed heat dissipation grooves on the outer surface of the copper liner ring 8 increase the air gap area between the outer surface of the copper liner ring 8 and the inner wall of the pipe fitting. Welding heat is conducted through the copper liner ring 8 to the wall of the heat dissipation groove and then dissipates into the air within the groove, reducing the peak temperature rise of the copper liner ring 8 and decreasing its radial thermal expansion. This further ensures that the copper liner ring 8 can be smoothly removed from the inner cavity of the pipe fitting after welding. Simultaneously, no metallurgical bond is formed between the copper and aluminum solder, and the outer surface of the copper liner ring 8 does not adhere to the weld root, ensuring that the copper liner ring 8 can be completely removed axially during disassembly.
[0050] The embodiments of the present invention have been described above. However, the embodiments are not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make more equivalent embodiments under the guidance of the present embodiments, and all of them are within the protection scope of the present embodiments.
Claims
1. A positioning arc welding device for aluminum product processing, characterized in that, include: The frame (1) includes two side columns and a crossbeam, and each side column is equipped with a bearing seat (3) at the top. The mandrel (2) is supported at both ends by bearings (4) in the bearing seats (3) on both sides. Two annular snap ring grooves are provided on the outer circular surface of the middle part of the mandrel (2) at intervals along the axial direction. A copper liner ring (8) is fitted in the section between two retaining ring grooves in the middle of the mandrel (2). The inner hole of the copper liner ring (8) is in clearance fit with the outer circular surface of the mandrel (2). The outer circular surface of the copper liner ring (8) is close to the inner wall surface of the butt joint area of the thin-walled aluminum tube (17). A pair of C-shaped retaining rings (9) are respectively embedded in two retaining ring grooves. The radial outer edge of each C-shaped retaining ring (9) protrudes from the outer circular surface of the spindle (2) to form an axial shoulder. The two C-shaped retaining rings (9) respectively abut against the two axial end faces of the copper pad ring (8), limiting the copper pad ring (8) to the axial range between the two retaining ring grooves from both axial sides. Two sets of internal expansion clamping components are respectively fitted on both ends of the mandrel (2) and symmetrically distributed on both sides of the copper pad ring (8). Each set of internal expansion clamping components includes an elastic support body. After being axially compressed, the elastic support body expands radially and adheres tightly to the inner wall of the thin-walled aluminum tube (17). A rotary drive assembly is mounted on the frame (1) and connected to one end of the spindle (2) to drive the spindle (2) to rotate around its own axis; The welding torch holder (14) is fixed on the crossbeam of the frame (1) and extends toward the area where the copper pad ring (8) is located. The welding torch holder (14) is equipped with a welding torch clamp (15) at the end.
2. The aluminum product processing positioning arc welding device according to claim 1, characterized in that, Each end section of the mandrel (2) has an external thread segment on its outer circular surface. Each external thread segment is located on the side of the corresponding internal expansion clamping assembly away from the copper liner ring (8). Each set of internal expansion clamping assemblies includes a rubber drum ring (5), two metal pressure rings (6), and a locking nut (7). The rubber drum ring (5) is a circular elastic body, which is fitted onto the outer circular surface of the mandrel (2) as an elastic support. The two metal pressure rings (6) are respectively fitted onto the mandrel (2) and abut against the two axial end faces of the rubber drum ring (5). The inner hole of the metal pressure ring (6) is clearance-fitted with the outer circular surface of the mandrel (2). The locking nut (7) is screwed onto the corresponding external thread segment and forms a helical pair with the mandrel (2). The locking nut (7) is screwed along the corresponding external thread segment. When the rubber drum ring (5) is pushed axially, the end face of the locking nut (7) abuts against the metal pressure ring (6) on the side away from the copper liner ring (8), pushing the metal pressure ring (6) to compress the rubber drum ring (5) axially; the metal pressure ring (6) on the side close to the copper liner ring (8) is axially stopped by the radial outer edge of the corresponding C-shaped retaining ring (9); the two metal pressure rings (6) clamp the rubber drum ring (5) from both sides axially, and the rubber drum ring (5) expands radially uniformly after being axially compressed. The outer circle of the rubber drum ring (5) is in close contact with the inner wall of the thin-walled aluminum tube (17), and the friction between the outer circle of the rubber drum ring (5) and the inner wall of the thin-walled aluminum tube (17) causes the thin-walled aluminum tube (17) to rotate synchronously around the axis with the mandrel (2).
3. The aluminum product processing positioning arc welding device according to claim 2, characterized in that, The radial outer edge of each C-shaped retaining ring (9) near the side of the internal expansion clamping assembly abuts against the corresponding axial end face of the copper liner ring (8) on one side along the axial direction, and the radial outer edge abuts against the end face of the metal pressure ring (6) near the side of the copper liner ring (8) on the other side along the axial direction.
4. The aluminum product processing positioning arc welding device according to claim 1, characterized in that, The axial width of the copper gasket ring (8) covers the area where the joint of the two thin-walled aluminum tubes (17) is located; a unilateral radial gap is maintained between the outer diameter of the copper gasket ring (8) and the inner diameter of the thin-walled aluminum tube (17). ,in The distance between the outer surface of the copper gasket ring (8) and the inner wall of the thin-walled aluminum tube (17) in the radial direction on one side. The value ranges from 0.3 mm to 0.8 mm.
5. The aluminum product processing positioning arc welding device according to claim 1, characterized in that, Several heat dissipation grooves are provided on the outer circular surface of the copper liner ring (8) along the axial direction. Each heat dissipation groove is evenly distributed along the circumference of the copper liner ring (8). Each heat dissipation groove extends along the axial direction and penetrates to the two axial end faces of the copper liner ring (8).
6. The aluminum product processing positioning arc welding device according to claim 5, characterized in that, The heat dissipation groove is a long strip-shaped groove, and the depth of the heat dissipation groove is less than one-third of the wall thickness of the copper liner ring (8).
7. The aluminum product processing positioning arc welding device according to claim 1, characterized in that, The rotary drive assembly includes a worm wheel (10), a worm (11), a worm bearing seat (12), and a geared motor (13). The worm wheel (10) is fixed to the end of the spindle (2) that extends out of the bearing seat (3) on one side by a key connection, and the worm wheel (10) rotates synchronously with the spindle (2). The worm (11) is mounted on a column on one side of the frame (1) through the worm bearing seat (12), and the axis of the worm (11) is perpendicular to the axis of the spindle (2). The worm (11) meshes with the worm wheel (10) to form a worm wheel and worm gear transmission pair. The geared motor (13) is fixed on a column on one side of the frame (1) and connected to one end of the worm (11). The geared motor (13) drives the worm (11) to rotate around its own axis, and the worm (11) drives the spindle (2) to rotate at a constant speed around its own axis through the worm wheel (10).
8. The aluminum product processing positioning arc welding device according to claim 1, characterized in that, The welding torch holder (14) is an L-shaped bracket. The vertical section of the welding torch holder (14) is fixed to the middle of the crossbeam of the frame (1) by bolts. The horizontal section of the welding torch holder (14) extends towards the area where the copper pad ring (8) is located. The welding torch clamp (15) is installed at the end of the horizontal section of the welding torch holder (14). The welding torch (16) is clamped in the welding torch clamp (15). The nozzle of the welding torch (16) is vertically downward and aligned with the highest point of the butt joint of the thin-walled aluminum tube (17). The welding torch (16) remains fixed during the rotation of the thin-walled aluminum tube (17) around the axis.
9. The aluminum product processing positioning arc welding device according to claim 1, characterized in that, Each C-shaped retaining ring (9) is an elastic ring with an opening. After being radially compressed, the C-shaped retaining ring (9) is embedded in the corresponding retaining ring groove. The C-shaped retaining ring (9) expands radially and clamps itself in the retaining ring groove by its own elastic restoring force. When the copper pad ring (8) tends to move along the axial direction, the end face of the copper pad ring (8) makes surface contact with the radial outer edge of the corresponding C-shaped retaining ring (9) to stop it. The C-shaped retaining ring (9) transmits the axial force to the groove wall of the retaining ring groove, which is borne by the mandrel (2) as a whole.
10. The aluminum product processing positioning arc welding device according to claim 1, characterized in that, The frame (1) is a portal frame structure, including two side columns and a crossbeam connected to the top of the two side columns. The bearing seat (3) is fixedly installed on the top of the two side columns, and the axis of the spindle (2) extends in the horizontal direction.