Automobile suspension swing arm welding device and welding method

Abstract

The invention discloses a welding device and a welding method for automobile suspension swing arm parts, and relates to the technical field of automobile swing arm parts welding, comprising: a frame; a plurality of center shafts, which are fixedly mounted on the frame, and a rotating sleeve is rotatably connected to the center shaft; a transmission assembly, which is transmission-connected to the rotating sleeve; a power assembly, which drives the rotating sleeve to rotate through the transmission of the transmission assembly; a positioning part, which is used for positioning the lower swing arm blank, and the positioning part comprises a first positioning pin and a second positioning pin fixedly mounted on the outside of the rotating sleeve; in the above technical scheme, the present invention automatically performs centralized flipping of the lower swing arm blank during full welding, thereby improving welding efficiency, and during the flipping process, the pressing block passively extends out and moves toward the lower swing arm blank to achieve fixing and locking of the lower swing arm blank, and the pressing block can avoid the welding path, and does not need to be clamped for a second time, thereby further improving welding efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of automobile swing arm welding, and in particular to an automobile suspension swing arm welding device and a welding method. Background Art

[0002] The lower arm is an important part of the automobile suspension system. The double-layer stamped steel plate lower arm refers to a lower arm structure composed of two layers of steel plates. Its design principle is to fix the upper and lower layers of steel plates together by welding and other methods to form an integral structure. This design method can not only improve the rigidity and strength of the lower arm, but also effectively reduce the weight of the vehicle and has the characteristics of improving vehicle stability.

[0003] Currently, when welding, it is necessary to put the overlapped lower arm blank into a specific fixture, clamp the lower arm blank by the fixture to ensure that the lower arm blank is completely fitted, and then perform spot welding or full welding along a pair of lower arm blank gaps through welding equipment. However, the fixture is on the welding path. When spot welding is performed, the welding point can be avoided by the clamping point being in a specific position. However, when full welding is performed, the fixture needs to be avoided accordingly, and the welding needs to be interrupted to replace the clamping point of the fixture, which will inevitably lead to a decrease in welding continuity and affect the improvement of welding efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide a welding device and a welding method for an automobile suspension swing arm to solve the deficiencies in the above-mentioned prior art.

[0005] In order to achieve the above-mentioned purpose, the present invention provides the following technical solution: a welding device for automobile suspension swing arm, comprising:

[0006] frame;

[0007] A plurality of central shafts, wherein the plurality of central shafts are fixedly mounted on the frame, and a rotating sleeve is rotatably connected to the central shaft;

[0008] A transmission assembly, which is in transmission connection with the rotating sleeve;

[0009] A power assembly, which drives the rotating sleeve to rotate through the transmission of the transmission assembly;

[0010] A positioning part, which is used for positioning the lower swing arm blank, and the positioning part includes a first positioning pin and a second positioning pin fixedly mounted on the outside of the rotating sleeve;

[0011] The locking assembly includes a pressing block and a linkage part, wherein the pressing block is slidably connected in the second positioning pin, and the linkage part is used to drive the pressing block to move, and the pressing block has a loading position and a welding position. When in the loading position, the pressing block is inside the second positioning pin, and in the welding position, the pressing block squeezes the lower swing arm blank;

[0012] When switching from the loading position to the welding position, the rotating sleeve rotates, and the linkage part drives the pressing block to extend the second positioning pin and move toward the position of the lower swing arm blank to fix the lower swing arm blank.

[0013] Preferably, the transmission assembly includes a belt, a pulley, a first gear, a second gear and a chain. The pulley is fixedly mounted on the central shaft, and the multiple pulleys are connected by belt transmission. The first gear is fixedly mounted on one of the central shafts, and the second gear is mounted on the output shaft of the power assembly. The first gear and the second gear are connected by chain transmission.

[0014] Preferably, the linkage part includes a sliding groove, a tension rod, a connecting rod, a first elastic member, a second elastic member, and a trigger block. The sliding groove is opened in the second positioning pin, the pressing block is slidably connected in the sliding groove, the tension rod slides through the second positioning pin, one end of the connecting rod is highly mounted on the pressing block, the other end of the connecting rod is slidably inserted in the tension rod, the first elastic member is movably sleeved on the outside of the connecting rod, the second elastic member is movably sleeved on the tension rod, and the trigger block is fixedly mounted on the end of the center axis.

[0015] Preferably, at the loading position, the trigger block is located on the moving path of the tension rod, and the end of the tension rod abuts against the trigger block.

[0016] Preferably, in the welding position, the tension rod and the trigger block are separated.

[0017] Preferably, the sliding groove is provided with a sloped area, and the distance from the center line of the second positioning pin increases from one end to the other end of the sloped area.

[0018] Preferably, one end of the first elastic member abuts against the tension rod, and the other end of the first elastic member abuts against the pressing block.

[0019] Preferably, the second elastic member applies a thrust to the tension rod in the direction of the central axis.

[0020] Preferably, there are two welding positions, and the two welding positions are obtained by rotating the rotating sleeve 90 degrees and 270 degrees respectively with the loading position as the starting point.

[0021] A method for welding a vehicle suspension swing arm comprises the following steps:

[0022] S1, assembling the lower swing arm blank to the positioning portion so that the first positioning pin and the second positioning pin are inserted into the hole of the lower swing arm blank;

[0023] S2, the rotating sleeve rotates 90 degrees so that the weld on one side of the lower arm blank faces upward, and the welding robot is used to weld the weld on the side;

[0024] S3, the rotating sleeve continues to rotate 180 degrees so that the weld on the other side of the lower arm blank faces upward, and the welding robot is used to weld the weld on the other side;

[0025] S4, welding is completed, the rotating sleeve is reset to the loading position, and the lower swing arm blank is removed after welding.

[0026] In the above technical scheme, the present invention provides a welding device and a welding method for automobile suspension arm parts. When full welding is performed, the lower arm blank is automatically flipped over centrally to improve welding efficiency. During the flipping process, the pressing block is passively extended and moved toward the lower arm blank to fix and lock the lower arm blank. The pressing block can avoid the welding path and does not need to be clamped for the second time, thereby further improving welding efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a schematic diagram of the overall structure of a welding device and a welding method for a vehicle suspension swing arm according to the present invention;

[0029] Figure 2 It is a structural schematic diagram of a welding device and welding method for a vehicle suspension swing arm of the present invention at a loading position;

[0030] Figure 3 This is an appendix of a welding device and a welding method for a vehicle suspension swing arm of the present invention. Figure 2 The schematic diagram of the structure after the enlargement of A in the middle;

[0031] Figure 4 It is a structural schematic diagram of a welding position of a welding device and a welding method for a vehicle suspension swing arm of the present invention;

[0032] Figure 5 This is an appendix of a welding device and a welding method for a vehicle suspension swing arm of the present invention. Figure 4 The enlarged schematic diagram of point E in the middle;

[0033] Figure 6 It is a schematic diagram of the central axis structure of a welding device and welding method for a vehicle suspension swing arm of the present invention;

[0034] Figure 7It is a schematic diagram of the structure of a rotating sleeve of a welding device and a welding method for a vehicle suspension swing arm of the present invention;

[0035] Figure 8 It is a structural schematic diagram of the linkage part of a welding device and a welding method for a vehicle suspension swing arm of the present invention when the welding device and the welding method are in a loading position;

[0036] Fig. 9 This is an appendix of a welding device and a welding method for a vehicle suspension swing arm of the present invention. Figure 8 The schematic diagram of the structure after the enlargement of B in the middle;

[0037] Fig.10 It is a schematic diagram of the linkage structure of a welding device and a welding method for a vehicle suspension swing arm of the present invention when the device and the welding method are in a welding position;

[0038] Fig.11 This is an appendix of a welding device and a welding method for a vehicle suspension swing arm of the present invention. Fig.10 The schematic diagram of the structure after enlarging at C in the middle;

[0039] Fig.12 This is an appendix of a welding device and a welding method for a vehicle suspension swing arm of the present invention. Fig.10 Schematic diagram of the structure after enlarging point D in the middle.

[0040] Explanation of the accompanying drawings: 1. frame; 2. center axis; 3. rotating sleeve; 32. first positioning pin; 321. movable sleeve; 33. second positioning pin; 4. power assembly; 5. transmission assembly; 51. belt; 52. pulley; 53. first gear; 54. second gear; 55. chain; 6. lower swing arm blank; 7. locking assembly; 71. sliding groove; 711. inclined area; 72. pressing block; 73. tension rod; 74. connecting rod; 75. first elastic member; 76. second elastic member; 8. trigger block. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0042] See also Figure 1-12 , an embodiment of the present invention provides a welding device for a vehicle suspension swing arm, comprising:

[0043] Rack 1;

[0044] A plurality of central shafts 2 are fixedly mounted on the frame 1, and a rotating sleeve 3 is rotatably connected to the central shaft 2;

[0045] A transmission assembly 5, which is transmission-connected to the rotating sleeve 3;

[0046] A power assembly 4, the power assembly 4 drives the rotating sleeve 3 to rotate through the transmission assembly 5;

[0047] A positioning part, which is used for positioning the lower swing arm blank 6, and the positioning part includes a first positioning pin 32 and a second positioning pin 33 fixedly mounted on the outside of the rotating sleeve 3;

[0048] The locking assembly 7 includes a pressing block 72 and a linkage part. The pressing block 72 is slidably connected in the second positioning pin 33. The linkage part is used to drive the pressing block 72 to move. The pressing block 72 has a loading position and a welding position. When in the loading position, the pressing block 72 is inside the second positioning pin 33. In the welding position, the pressing block 72 squeezes the lower swing arm blank 6.

[0049] When switching from the loading position to the welding position, the rotating sleeve 3 rotates, and the linkage part drives the pressing block 72 to extend the second positioning pin 33 and move toward the position of the lower swing arm blank 6 to fix the lower swing arm blank 6.

[0050] A plurality of central shafts 2 are fixedly mounted on the frame 1, and each central shaft 2 is rotatably connected to a rotating sleeve 3, and each rotating sleeve 3 is connected to each other through a transmission assembly 5, so that each rotating sleeve 3 can rotate synchronously;

[0051] The first locating pin 32 and the second locating pin 33 are both fixed on the rotating sleeve 3, and the first locating pin 32 and the second locating pin 33 are adapted to the lower swing arm blank 6, so that the lower swing arm blank 6 can be installed on the first locating pin 32 and the second locating pin 33, and the first locating pin 32 and the second locating pin 33 provide a positioning function, which is helpful for batch processing, and the first locating pin 32 and the second locating pin 33 also play a testing role. When the lower swing arm blank 6 cannot be assembled with the first locating pin 32 and the second locating pin 33, it means that the size of the lower swing arm blank 6 is unqualified, and it plays a testing role while loading;

[0052] The pressing block 72 is slidably connected to the second positioning pin 33. In the loading position, the pressing block 72 is retracted into the second positioning pin 33. At this time, the lower swing arm blank 6 can be smoothly sleeved on the first positioning pin 32 and the second positioning pin 33. By rotating the rotating sleeve 3, the linkage part will drive the pressing block 72 to move, and the pressing block 72 extends out of the second positioning pin 33 and moves toward the lower swing arm blank 6. In this way, the pressing block 72 is used to squeeze the lower swing arm blank 6 so that the lower swing arm blank 6 is fixed, which facilitates welding. By rotating the rotating sleeve 3 90 degrees and 270 degrees, full welding of the gap of the lower swing arm blank 6 can be achieved respectively. While the rotating sleeve 3 rotates automatically, the pressing block 72 is passively extended and moved toward the lower swing arm blank 6 to fix and lock the lower swing arm blank 6, and the pressing block 72 can avoid the welding path, and does not need to be clamped twice, thereby further improving the welding efficiency.

[0053] In the embodiments of the present invention, please refer to Figure 1 The transmission assembly 5 includes a belt 51, a pulley 52, a first gear 53, a second gear 54 and a chain 55. The pulley 52 is fixedly mounted on the central shaft 2, and multiple pulleys 52 are connected by the belt 51. The first gear 53 is fixedly mounted on one of the central shafts 2, and the second gear 54 is mounted on the output shaft of the power assembly 4. The first gear 53 and the second gear 54 are connected by the chain 55.

[0054] The power component 4 is configured as a servo motor, which can drive the second gear 54 to rotate. The second gear 54 can drive the first gear 53 to rotate under the transmission of the chain 55, and the first gear 53 is fixedly installed on the rotating sleeve 3, so that the rotating sleeve 3 rotates synchronously. When the rotating sleeve 3 rotates, it can drive the pulley 52 installed outside it to rotate, and the pulleys 52 are connected by a belt 51. In this way, the synchronous rotation of multiple rotating sleeves 3 can be achieved. After completing a set of welding, the lower swing arm blank 6 can be synchronously flipped.

[0055] In the embodiments of the present invention, please refer to Figure 2-3 , Figure 8-12 The linkage part includes a sliding groove 71, a tension rod 73, a connecting rod 74, a first elastic member 75, a second elastic member 76, and a trigger block 8. The sliding groove 71 is opened in the second positioning pin 33, the pressing block 72 is slidably connected in the sliding groove 71, the tension rod 73 slides through the second positioning pin 33, one end of the connecting rod 74 is highly mounted on the pressing block 72, and the other end of the connecting rod 74 is slidably inserted in the tension rod 73, the first elastic member 75 is movably sleeved on the outside of the connecting rod 74, the second elastic member 76 is movably sleeved on the tension rod 73, and the trigger block 8 is fixedly mounted on the end of the central axis 8.

[0056] The sliding groove 71 is provided in the second positioning pin 33, and the pressing block 72 is slidably connected in the sliding groove 71. The pressing block 72 is always in contact with the sliding groove 71. Under the elastic force of the second elastic member 76, the tension rod 73 always has a tendency to move toward the direction where the rotating sleeve 3 is located. The tension rod 73 is slidably connected with the pressing block 72 under the connection of the connecting rod 74. In the loading position, as shown in the attached Fig. 9 As shown in FIG. 1 , at this time, the trigger block 8 is used to resist the tension rod 73 to resist the thrust of the second elastic member 76. After the rotation, Fig.12 As shown, at this time, the tension rod 73 and the trigger block are separated, so the tension rod 73 moves toward the rotating sleeve 3, and the tension rod 73 can synchronously drive the pressing block 72 to move. Fig. 9 As shown in the figure, the sliding groove 71 is provided with an inclined surface area 711. As the pressing block 72 moves toward the rotating sleeve 3, under the elastic force of the first elastic member 75, the pressing block 72 will be close to the inclined surface area 711. Since the distance between the inclined surface area 711 and the center line of the second positioning pin 33 increases, the pressing block 72 will extend outward. As the pressing block 72 gradually approaches the rotating sleeve 3, the extension amount of the pressing block 72 will also increase until it is as shown in the figure. Fig.11 As shown in , the pressing block 72 will be squeezed on the lower swing arm blank 6 at this time, and under the elastic force of the second elastic member 76, the lower swing arm blank 6 is firmly squeezed by the pressing block 72, so that during the flipping process, the pressing block 72 is passively extended and squeezed toward the lower swing arm blank 6 to achieve the fixing and locking of the lower swing arm blank 6, and when loading, the pressing block 72 is retracted into the second positioning pin 33 to clamp the lower swing arm blank 6 from the end, so that the welding path can be avoided, and a pair of lower swing arm blanks 6 can be fully welded without secondary clamping, thereby further improving the welding efficiency.

[0057] By rotating the lower swing arm blank 6, there is an additional advantage. During the rotation of the rotating sleeve 3, not only the lower swing arm blank 6 is clamped and fixed, but the lower swing arm blank 6 is also synchronously flipped 90 degrees and 270 degrees, so that the welding gap of the lower swing arm blank 6 is always in an upward state, which greatly facilitates welding. Compared with welding from the side, welding from the top has a larger space, which greatly facilitates the spatial layout of the welding robot. In this way, the welding equipment is more compact and the space utilization rate is improved.

[0058] In the embodiments of the present invention, please refer to Fig. 9 In the loading position, the trigger block 8 is in the moving path of the tension rod 73 , and the end of the tension rod 73 abuts against the trigger block 8 .

[0059] Under the elastic force of the second elastic member 76, the tension rod 73 tends to move toward the central axis 2. At the loading position, the trigger block 8 is on the moving path of the tension rod 73. In this way, the trigger block 8 resists the tension rod 73 to prevent the tension rod 73 from being displaced, thereby ensuring that the pressing block 72 can be retracted into the second positioning pin 33, thereby ensuring that at the loading position, the lower swing arm blank 6 can be smoothly sleeved on the first positioning pin 32 and the second positioning pin 33.

[0060] In the embodiments of the present invention, please refer to Figure 10-12 , in the welding position, the tension rod 73 and the trigger block 8 are separated.

[0061] After the rotating sleeve 3 rotates, the moving path of the tension rod 73 will change, while the position of the trigger block 8 remains unchanged. In this way, the trigger block 8 is not on the moving path of the tension rod 73. Under the elastic force of the second elastic member 76, the tension rod 73 will move toward the central axis 2. During the displacement of the tension rod 73, the pressing block 72 can be driven to move, and the pressing block 72 can be used to extrude the lower swing arm blank 6 to fix the lower swing arm blank 6.

[0062] In the embodiments of the present invention, please refer to Fig. 9 The sliding groove 71 is provided with a sloped area 711 , and the distance from the center line of the second positioning pin 33 increases from one end to the other end of the sloped area 711 .

[0063] By setting the inclined surface area 711, when the pressing block 72 moves toward the central axis 2, the first elastic member 75 squeezes the pressing block 72 to make it fit the inclined surface area 711. In this way, since the distance between the center line of the inclined surface area 711 and the second positioning pin 33 increases from one end to the other end, the pressing block 72 will extend out of the second positioning pin 33 to fix the lower swing arm blank 6.

[0064] In the embodiments of the present invention, please refer to Fig.10 , Fig.11 One end of the first elastic member 75 abuts against the tension rod 73 , and the other end of the first elastic member 75 abuts against the pressing block 72 .

[0065] The pressing block 72 is squeezed by the first elastic member 75 so that the pressing block 72 can extend outward from the second positioning pin 33 . The pressing block 72 can extend outward while being displaced toward the outer center axis 2 , so as to fix the lower swing arm blank 6 .

[0066] In the embodiments of the present invention, please refer to Fig. 9 The second elastic member 76 applies a thrust to the tension rod 73 in the direction of the central axis 2 .

[0067] The tension rod 73 and the second positioning pin 33 are slidably connected. Under the elastic force of the second elastic member 76 , the tension rod 73 tends to move toward the direction of the central axis 2 .

[0068] In another embodiment of the present invention, please refer to Figure 3 A movable sleeve 321 is provided at the lower part of the first positioning pin 32, and the sliding sleeve 321 is fixed to the outside of the rotating sleeve 3 by bolts.

[0069] The sliding sleeve 321 can be laterally displaced along the axial direction of the rotating sleeve 3 , so that the position of the first positioning pin 32 is adjusted accordingly according to the different sizes of the lower swing arm blank 6 to meet the positioning requirements of different lower swing arm blanks 6 .

[0070] In the embodiment of the present invention, there are two welding positions, and the two welding positions are obtained by rotating the rotating sleeve 3 90 degrees and 270 degrees respectively with the loading position as the starting point.

[0071] When fully welding the lower swing arm blank 6, in order to ensure that all the gaps in the lower swing arm blank 6 are welded, it is necessary to first rotate 90 degrees to weld one side of the lower swing arm blank 6. After welding is completed, continue to rotate 180 degrees to facilitate welding of the other side of the lower swing arm blank 6.

[0072] A method for welding a vehicle suspension swing arm comprises the following steps:

[0073] S1, assembling the lower swing arm blank 6 to the positioning portion so that the first positioning pin 32 and the second positioning pin 3 are inserted into the holes of the lower swing arm blank 6;

[0074] S2, the rotating sleeve 3 rotates 90 degrees so that the weld seam on one side of the lower arm blank 6 faces upward, and the welding robot is used to weld the weld seam on the side;

[0075] S3, the rotating sleeve 3 continues to rotate 180 degrees, so that the weld on the other side of the lower arm blank 6 faces upward, and the welding robot is used to weld the weld on the side;

[0076] S4, welding is completed, the rotating sleeve 3 is reset to the loading position, and the lower swing arm blank 6 after welding is completed is removed.

[0077] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A welding device for automobile suspension swing arm, characterized in that: include: Rack (1); A plurality of central shafts (2), wherein the plurality of central shafts (2) are fixedly mounted on the frame (1), and a rotating sleeve (3) is rotatably connected to the central shaft (2); A transmission assembly (5) which is in transmission connection with the rotating sleeve (3); A power assembly (4), the power assembly (4) drives the rotating sleeve (3) to rotate through the transmission of the transmission assembly (5); A positioning part, which is used for positioning the lower swing arm blank (6), and the positioning part comprises a first positioning pin (32) and a second positioning pin (33) fixedly mounted on the outside of the rotating sleeve (3); The locking assembly (7) comprises a pressing block (72) and a linkage part, wherein the pressing block (72) is slidably connected in the second positioning pin (33), and the linkage part is used to drive the pressing block (72) to move, and the pressing block (72) has a loading position and a welding position. When in the loading position, the pressing block (72) is located in the second positioning pin (33), and when in the welding position, the pressing block (72) squeezes the lower swing arm blank (6); When switching from the loading position to the welding position, the rotating sleeve (3) rotates, and the linkage part drives the pressing block (72) to extend the second positioning pin (33) and move toward the position where the lower swing arm blank (6) is located, so as to fix the lower swing arm blank (6); The linkage part includes a sliding groove (71), a tension rod (73), a connecting rod (74), a first elastic member (75), a second elastic member (76), and a trigger block (8); the sliding groove (71) is opened in the second positioning pin (33); the pressing block (72) is slidably connected in the sliding groove (71); the tension rod (73) slides through the second positioning pin (33); one end of the connecting rod (74) is fixedly mounted on the pressing block (72); the other end of the connecting rod (74) is slidably inserted in the tension rod (73); the first elastic member (75) is movably sleeved on the outside of the connecting rod (74); the second elastic member (76) is movably sleeved on the tension rod (73); and the trigger block (8) is fixedly mounted on the end of the central axis (2); At the loading position, the trigger block (8) is located on the moving path of the tension rod (73), and the end of the tension rod (73) abuts against the trigger block (8); In the welding position, the tension rod (73) and the trigger block (8) are separated; The sliding groove (71) is provided with an inclined surface area (711), and the distance from the center line of the second positioning pin (33) increases gradually from one end to the other end of the inclined surface area (711); One end of the first elastic member (75) abuts against the tension rod (73), and the other end of the first elastic member (75) abuts against the pressing block (72); The second elastic member (76) applies a thrust to the tension rod (73) in the direction of the central axis (2).

2. The welding device for automobile suspension swing arm according to claim 1, characterized in that: The transmission assembly (5) comprises a belt (51), a pulley (52), a first gear (53), a second gear (54) and a chain (55); the pulley (52) is fixedly mounted on the central shaft (2); a plurality of pulleys (52) are connected to each other via a belt (51); the first gear (53) is fixedly mounted on one of the central shafts (2); the second gear (54) is mounted on the output shaft of the power assembly (4); and the first gear (53) and the second gear (54) are connected to each other via a chain (55).

3. The welding device for automobile suspension swing arm according to claim 1, characterized in that: There are two welding positions, and the two welding positions are obtained by rotating the rotating sleeve (3) by 90 degrees and 270 degrees respectively, with the loading position as the starting point.

4. A method for welding a vehicle suspension swing arm, which is implemented based on the welding device according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, assembling the lower swing arm blank (6) to the positioning portion so that the first positioning pin (32) and the second positioning pin (33) are inserted into the holes of the lower swing arm blank (6); S2, the rotating sleeve (3) is rotated 90 degrees so that the weld seam on one side of the lower swing arm blank (6) faces upward, and the weld seam on one side of the lower swing arm blank (6) is welded by a welding robot; S3, the rotating sleeve (3) continues to rotate 180 degrees so that the weld seam on the other side of the lower swing arm blank (6) faces upward, and the welding robot is used to weld the weld seam on the other side of the lower swing arm blank (6); S4, welding is completed, the rotating sleeve (3) is reset to the loading position, and the lower swing arm blank (6) after welding is completed is removed.

Images