Welding device for rear lower control arm of automobile

Abstract

The invention provides an automobile rear lower control arm welding device which comprises a base, a support and a side positioning block used for positioning a connecting block are arranged at the upper end of the base, two lower positioning columns used for positioning a control arm are elastically and telescopically arranged at the upper end of the base, and an air cylinder is downwards arranged at the top end of the support. A flat plate is transversely arranged at the end of a piston rod of the air cylinder, the left side and the right side of the lower end of the flat plate are connected with a left connecting column and a right connecting column respectively, the end of the right connecting column is connected with a positioning piece used for positioning the upper cover plate and the control arm, and the left connecting column is connected with an inner transverse welding assembly. The automatic welding device has the advantages that the control arm and the upper cover plate are well positioned through the positioning piece, then the upper cover plate is automatically corrected through the displacement piece, the outer arc winding welding of the upper cover plate and the inner transverse welding of the connecting block are automatically completed, the automation degree is high, and the welding quality is improved.

Description

Technical Field

[0001] The invention relates to the technical field of welding, and in particular to a welding device for a rear lower control arm of an automobile. Background Art

[0002] The multi-link suspension system of an automobile can provide support for both the upper and lower parts of the wheels, and has good strength and stability. The rear lower control arm is an important component of the multi-link suspension, and is mainly used to bear various forces and moments transmitted by the tires during the driving process of the vehicle. It is widely used in fuel vehicles and new energy vehicles. The rear lower control arm consists of a connecting block, an upper cover plate and an integrally formed control arm. The bottom of the control arm is provided with two circular holes distributed on the left and right. After the control arm is processed, the outer circle of the upper cover plate and the outer arc of the upper end surface of the control arm need to be welded, and the connecting block and the inner horizontal welding of the inner side of the control arm are required. Figure 6 , 7 As shown in , 8, at present, the welding of the upper cover plate and the connecting block is done manually, which not only requires repeated adjustment of the upper cover plate so that the axis of the upper cover plate coincides with the axis of the right hole at the bottom of the control arm, but also requires the upper cover plate to be corrected so that the left end face of the upper cover plate remains longitudinal, and then it is necessary to clamp the connecting block and the upper cover plate while welding the connecting block and the upper cover plate. During the welding process, the outer arc rotation welding of the front and rear surfaces of the upper cover plate and the inner horizontal welding of the front and rear sides of the connecting block are also required, which is time-consuming and labor-intensive and it is difficult to ensure the quality of welding. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a welding device for the rear lower control arm of an automobile, which positions the control arm and the upper cover plate through a positioning member, and then automatically completes the correction of the upper cover plate through a displacement member, the outer arc rotation welding of the upper cover plate and the inner horizontal welding of the connecting block, with a high degree of automation and improved welding quality.

[0004] The present invention provides a welding device for a rear lower control arm of an automobile, comprising a base 1, wherein a bracket 2 and a side positioning block 3 for positioning a connecting block are arranged at the upper end of the base 1, and two lower positioning columns 4 for positioning the control arm are elastically and telescopically arranged at the upper end of the base 1, and a cylinder 5 is arranged downward at the top end of the bracket 2, and a flat plate 6 is transversely arranged at the end of the piston rod of the cylinder 5, and the left and right sides of the lower end of the flat plate 6 are respectively connected to a left connecting column and a right connecting column, and the end of the right connecting column is connected to a positioning member 7 for positioning an upper cover plate and a control arm. The left connecting column is connected to an inner horizontal welding component 11, and the inner horizontal welding component 11 is slidably equipped with a displacement member 9 driven by a servo motor 8, and the flat plate 6 and the right connecting column are provided with an outer arc welding component 12. A return component 10 is provided at the bottom of the displacement component 9. During the rightward movement of the displacement component 9, the displacement component 9 first drives the return component 10 to return the upper cover plate, and the displacement component 9 then drives the inner horizontal welding component 11 and the outer arc welding component 12 to weld the connecting block and the upper cover plate respectively.

[0005] Furthermore, the positioning member 7 is composed of a middle positioning plate 7.2 connected to an upper pressure plate 7.1 and a lower upper positioning column 7.3. The lower edge of the positioning plate 7.3 is provided with a rounded corner. The upper positioning column 7.3 corresponds to the lower positioning column 4 in upper and lower directions.

[0006] Furthermore, the displacement member 9 is composed of a middle horizontal bar 9.1 connecting the side thrust parts 9.4 and the mounting parts 9.3 on the left and right sides. A rack 9.2 is laterally arranged on the rear side of the upper end of the horizontal bar 9.1. A driving gear 15 meshing with the rack 9.2 is keyed on the output shaft of the servo motor 8. Partial teeth 9.5 are laterally arranged at the front end of the horizontal bar 9.1, and an avoidance groove 9.6 is opened on the left side of the front end of the horizontal bar 9.1.

[0007] Furthermore, the return assembly 10 includes a fixed tube 10.1 transversely arranged at the lower end of the mounting portion 9.3, a telescopic groove is transversely opened in the fixed tube 10.1, a telescopic rod 10.2 is slidably arranged in the telescopic groove, a first elastic member connecting the telescopic rod 10.2 and the telescopic groove is arranged in the telescopic groove, and a push block 10.3 is longitudinally arranged at the end of the telescopic rod 10.2.

[0008] Furthermore, the inner horizontal welding assembly 11 includes a fixing plate 11.1 horizontally connected to the left connecting column, and sliding holes 11.2 are horizontally and symmetrically opened on the front and rear sides of the upper end of the fixing plate 11.1. A sliding rod 11.3 is horizontally arranged in the sliding hole 11.2. A sliding block 11.4 that can be pushed sideways by the side pushing part 9.4 is slidably provided at the sliding hole 11.2 and the sliding rod 11.3. The sliding block 11.4 is outerly provided with a second elastic member connecting the sliding hole 11.2 and the sliding block 11.4, and a first welding gun is arranged at the bottom of the sliding block 11.4.

[0009] Furthermore, the first welding gun is locked to the bottom of the slide block 11.4 by a first locking bolt tilted inward.

[0010] Furthermore, a guide block 14 for slidingly fitting the cross bar 9.1 and the rack 9.2 is disposed at the rear end of the fixing plate 11.1.

[0011] Furthermore, the outer arc welding assembly 12 includes a locking gear 12.1 rotating under the flat plate 6, the locking gear 12.1 can be locked by the horizontal bar 9.1 and cooperate with the partial teeth 9.5, a first large gear 12.2 is coaxially connected to the top of the locking gear 12.1, a small gear 12.3 is meshed at the right end of the first large gear 12.2, a second large gear 12.4 is coaxially connected to the top of the small gear 12.3, a gear ring 12.5 meshing with the second large gear 12.4 is rotatably provided at the upper end of the right connecting column, two fixed columns 12.6 are evenly distributed on the gear ring 12.5 along its axis circumferentially, and a second welding gun is provided at the bottom of the fixed column 12.6.

[0012] Furthermore, the second welding gun is locked to the bottom of the fixing column 12.6 in an oblique manner outwardly by a second locking bolt, and the second welding gun intersects with the axis of the gear ring 12.5.

[0013] Furthermore, guide rods 13 are vertically and symmetrically arranged on the left and right sides of the upper end of the plate 6 , and the guide rods 13 are slidably fitted on the bracket 2 so as to move up and down.

[0014] The advantages of the present invention are as follows: the control arm and the upper cover plate are positioned by the positioning member, and then the upper cover plate is automatically corrected by the displacement member, and the outer arc rotation welding of the upper cover plate and the inner horizontal welding of the connecting block are completed, with a high degree of automation and improved welding quality; the cylinder is lowered to the bottom through the flat plate with the positioning member, the servo motor, the displacement member, the return assembly, the inner horizontal welding assembly, and the outer arc welding assembly, so that the welding gun is aligned with the welding position and the upper cover plate and the control arm are positioned; the connecting block is positioned by the side positioning block, and the upper positioning column presses the lower positioning column to enter the two holes of the control arm to prevent the control arm from rotating. After the positioning plate enters the inner circle of the upper cover plate, the pressure plate slightly presses the upper cover plate, so that the axis of the upper cover plate is in the correct position, so that the upper cover plate can be corrected later, thereby positioning the upper cover plate and the control arm; the servo motor drives the displacement member to move right through the rack, and the mounting part of the displacement member moves right with the return assembly, so that the upper cover plate is corrected, and the side push part and part of the teeth drive the inner horizontal welding assembly and the outer arc welding assembly to weld the connecting block and the upper cover plate respectively; the telescopic The push block on the rod contacts the side of the upper cover plate that can only rotate and returns the upper cover plate to the center. The push block presses the side of the upper cover plate under the action of the first elastic member and maintains the side pressure in the subsequent process, thereby positioning the upper cover plate; the side push block of the displacement member pushes the slider to move right along the slide groove and the slide rod, and the slider moves right with the first welding gun, and the first welding gun performs transverse welding on the connecting block and the inner side of the control arm. The slider and the first welding gun move to the right to the bottom, and at the same time, part of the teeth of the displacement member are engaged with the locking gear, and the locking gear rotates with the second large gear through the first large gear and the small gear, and the second large gear drives the gear ring to rotate, and the gear ring rotates with the two fixed columns and the second welding gun, and the second welding gun performs outer arc rotation welding on the outer ring of the upper cover plate; the first welding gun tilted inwardly can be moved laterally to weld the connecting block on the inner side of the control arm to ensure the welding quality; the second welding gun tilted outwardly performs rotation welding on the outer ring of the upper cover plate on the upper end face of the control arm by rotating to ensure the welding quality, and the intersection of the axis of the second welding gun and the gear ring can make the welding precise. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A perspective view of the present invention; Figure 2 It is a structural schematic diagram of the present invention; Figure 3 It is a front view of the present invention; Figure 4 A top view of the present invention; Figure 5 for Figure 4 AA section view; Figure 6 This is a schematic diagram of the structure of the present invention when the control arm, the connecting block and the upper cover plate are placed; Figure 7 This is a top view of the present invention when the control arm, the connecting block and the upper cover plate are placed; Figure 8It is a cross-sectional view of the flat plate of the present invention when it is moved down to the bottom and the positioning member has positioned the control arm and the upper cover plate; Fig. 9 It is a cross-sectional view of the displacement member of the present invention when it moves rightward and the push block returns to the upper cover plate; Fig.10 It is a cross-sectional view of the displacement member of the present invention when it moves to the right and the welding gun completes welding; Fig.11 for Figure 2 A magnified view of part B; Fig.12 for Figure 6 Enlarged view of part C; Fig.13 for Fig. 9 A magnified view of the D portion; Fig.14 It is a schematic structural diagram of the displacement member of the present invention; Fig.15 It is a schematic structural diagram of the positioning member of the present invention. DETAILED DESCRIPTION

[0016] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0017] See also Figures 1 to 15The present invention provides a welding device for a rear lower control arm of an automobile, which comprises a base 1, a bracket 2 and a side positioning block 3 for positioning a connecting block are arranged at the upper end of the base 1, the side positioning block is L-shaped, a placement groove for placing the connecting block is arranged at the upper end of the side positioning block, the front and rear sides of the connecting block are defined by the inner side wall of the control arm, and the left and right sides of the connecting block are defined by the placement groove, two lower positioning columns 4 for positioning the control arm are elastically and telescopically arranged at the upper end of the base 1, a cylinder 5 is arranged downward at the top end of the bracket 2, a plate 6 is arranged transversely at the end of the piston rod of the cylinder 5, guide rods 13 are arranged vertically and symmetrically at the left and right sides of the upper end of the plate 6, the guide rods 13 are slidably matched with the bracket 2 in an up-and-down manner, and the guide rods can guide the movement of the piston rod, To ensure that there will be no lateral deviation during the movement to avoid damage to the cylinder, the left and right sides of the lower end of the plate 6 are respectively connected to the left and right sides of the left and right connecting columns, and the end of the right connecting column is connected to a positioning member 7 for positioning the upper cover and the control arm, and the left connecting column is connected to an inner horizontal welding assembly 11, and the inner horizontal welding assembly 11 is equipped with a displacement member 9 driven by a servo motor 8 for sliding movement left and right. The flat plate 6 and the right connecting column are provided with an outer arc welding assembly 12, and a return assembly 10 is provided at the bottom of the displacement member 9. In the process of the displacement member 9 moving to the right, the displacement member 9 first drives the return assembly 10 to return the upper cover, and the displacement member 9 then drives the inner horizontal welding assembly 11 and the outer arc welding assembly 12 to weld the connecting block and the upper cover respectively. Place the control arm on the base and let the two lower positioning columns enter the two holes of the control arm to prevent the control arm from rotating. The side positioning column extends into the left side of the control arm. Place the connecting block and the upper cover on the side positioning column and the control arm respectively. The cylinder drives the plate to move downward. The plate passes through the left connecting column and the right connecting column with the positioning parts, servo motor, displacement parts, return assembly, inner transverse welding assembly, and outer arc welding assembly to the bottom. The positioning parts position the upper cover and the control arm and slightly press the upper cover. The servo motor drives the displacement parts to move right. The displacement parts first drive the return assembly to return the upper cover. The displacement parts then drive the inner transverse welding assembly and the outer arc welding assembly to weld the connecting block and the upper cover respectively (the inner side of the connecting block and the control arm is horizontally welded, and the outer ring of the upper cover and the upper end face of the control arm are arc-shaped welded). After welding is completed, the servo motor drives the displacement parts to move left and reset. The displacement parts drive the return assembly, the inner transverse welding assembly, and the outer arc welding assembly to reset. Then the cylinder drives the plate to move up and reset with each component.

[0018] The positioning member 7 is composed of a positioning plate 7.2 in the middle connected to a pressure plate 7.1 on the upper side and an upper positioning column 7.3 on the lower side. The lower edge of the positioning plate 7.3 is provided with a rounded corner, which enables the positioning plate to smoothly enter the inner circle of the upper cover plate. The upper positioning column 7.3 corresponds to the lower positioning column 4. The cylinder drives the flat plate and the positioning member to move downward, and the upper positioning column presses the lower positioning column to enter the two holes of the control arm to prevent the control arm from rotating. After the positioning plate enters the inner circle of the upper cover plate, the pressure plate slightly presses the upper cover plate, so that the axis of the upper cover plate is in the correct position (the axis of the arc inner wall in the middle of the control arm and the axis of the right hole at the bottom of the control arm are coincident, and the axis of the upper cover plate can coincide with the axis of the right hole at the bottom of the control arm), so that the upper cover plate can be corrected later, thereby positioning the upper cover plate and the control arm.

[0019] See also Figure 2 , Fig.11 , Fig.14 The displacement member 9 is composed of a horizontal bar 9.1 in the middle, connecting the side thrust parts 9.4 and the mounting part 9.3 on the left and right sides. A rack 9.2 is disposed transversely on the rear side of the upper end of the horizontal bar 9.1. A driving gear 15 meshing with the rack 9.2 is keyed on the output shaft of the servo motor 8. The front end of the horizontal bar 9.1 is transversely provided with partial teeth 9.5. The left side of the front end of the horizontal bar 9.1 is provided with an avoidance groove 9.6. The servo motor drives the driving gear to rotate, and the driving gear moves the displacement member to the right through the rack. The mounting part of the displacement member moves to the right with the return assembly, thereby returning the upper cover plate to the right. The side thrust part and the partial teeth drive the inner transverse welding assembly and the outer arc welding assembly to weld the connection block and the upper cover plate respectively.

[0020] The return assembly 10 includes a fixed tube 10.1 which is transversely arranged at the lower end of the mounting part 9.3, a telescopic slot is transversely opened in the fixed tube 10.1, a telescopic rod 10.2 is slidably arranged in the telescopic slot, a first elastic member connecting the telescopic rod 10.2 and the telescopic slot is arranged in the telescopic slot, and a push block 10.3 is longitudinally arranged at the end of the telescopic rod 10.2. When the displacement member moves to the right, the mounting part of the displacement member moves to the right with the return assembly, the push block on the telescopic rod contacts the side of the upper cover plate which can only rotate and returns the upper cover plate to the right (the staff will basically deflect a little when placing the upper cover plate), and the push block presses the side of the upper cover plate under the action of the first elastic member, and maintains the side pressure in the subsequent process, thereby positioning the upper cover plate.

[0021] The inner horizontal welding assembly 11 includes a fixed plate 11.1 horizontally connected to the left connecting column, and a sliding hole 11.2 is horizontally and symmetrically opened on the front and rear sides of the upper end of the fixed plate 11.1. The right end of the sliding hole is provided with a receiving hole for the sliding rod and the second elastic member to extend into, and a sliding rod 11.3 is horizontally arranged in the sliding hole 11.2. The sliding hole 11.2 and the sliding rod 11.3 are slidably provided with a slider 11.4 that can be pushed sideways by the side pushing part 9.4. The outer sleeve of the sliding rod 11.3 is provided with a second elastic member connecting the sliding hole 11.2 and the slider 11.4, and the bottom of the slider 11.4 is provided with a first welding gun. When the displacement member moves to the right, the side pushing block of the displacement member pushes the slider to move to the right along the slide groove and the sliding rod, and the slider moves to the right with the first welding gun, and the first welding gun performs horizontal welding on the inner side of the connecting block and the control arm. After the slider and the first welding gun move to the right to the bottom, the welding is completed, and the displacement member moves to the left to reset, and the slider and the first welding gun move to the left to reset under the action of the second elastic member.

[0022] See also Figure 8 , Fig.12 The first welding gun is locked to the bottom of the slider 11.4 by the first locking bolt tilted inward. The welding position of the connecting block is on the inner side of the control arm, and the first welding gun tilted inward moves horizontally to weld the connecting block to ensure the welding quality.

[0023] The rear end of the fixed plate 11.1 is provided with a guide block 14 for slidingly fitting the horizontal bar 9.1 and the rack 9.2. The guide blocks are distributed on both sides of the driving gear, and the horizontal movement of the displacement member is ensured by the guide blocks.

[0024] See also Figure 2 , Figure 4 , Figure 5The outer arc welding assembly 12 includes a locking gear 12.1 rotating under the flat plate 6. The locking gear 12.1 can be locked by the horizontal bar 9.1 and cooperate with the partial teeth 9.5. The locking gear is driven to rotate by the partial teeth. After the partial teeth are disengaged from the locking gear, the locking gear is locked by the horizontal bar. A first large gear 12.2 is coaxially connected to the top of the locking gear 12.1, and a small gear 12.3 is meshed at the right end of the first large gear 12.2. A second large gear 12.4 is coaxially connected to the top of the small gear 12.3. A gear ring 12.5 meshing with the second large gear 12.4 is rotatably provided on the upper end of the right connecting column. Two fixed columns 12.6 are evenly distributed on the gear ring 12.5 along its axis circumferentially, and a second welding gun is provided at the bottom of the fixed column 12.6. When the displacement piece moves to the right, the push block returns the upper cover plate to the center and keeps the upper cover plate under side pressure. Then some teeth of the displacement piece engage with the locking gear. The locking gear rotates with the second large gear through the first large gear and the small gear. The second large gear drives the gear ring to rotate. The gear ring rotates with the two fixed columns and the second welding gun. The second welding gun performs outer arc rotation welding on the outer ring of the upper cover plate and the upper end face of the control arm. After welding is completed, the displacement piece moves to the left and resets. Some teeth of the displacement piece drive the gear ring and the second welding gun to reverse and reset. Then some teeth disengage from the locking gear, and the locking gear is locked by the horizontal bar of the displacement piece.

[0025] The second welding gun is locked to the bottom of the fixing column 12.6 by the second locking bolt, and the second welding gun intersects with the axis of the gear ring 12.5. The welding position of the outer ring of the upper cover plate is at the upper end surface of the control arm. The second welding gun, which is tilted outward, rotates to ensure the welding quality, and the intersection of the axis of the second welding gun and the gear ring can make the welding accurate.

[0026] The specific working process of the present invention is as follows: Place the control arm on the base and insert the two lower positioning columns into the two holes of the control arm to prevent the control arm from rotating. The side positioning column extends into the left side of the control arm. Place the connecting block and the upper cover plate above the side positioning column and the control arm respectively. Figure 6 , Figure 7 As shown, the cylinder drives the plate to move downward, and the plate is lowered to the bottom through the left connecting column and the right connecting column with the positioning parts, the servo motor, the displacement parts, the return assembly, the inner horizontal welding assembly, and the outer arc welding assembly. The first welding gun and the second welding gun are aligned with the welding position, and the upper positioning column presses the lower positioning column to enter the two holes of the control arm to prevent the control arm from rotating. After the positioning plate enters the inner circle of the upper cover plate, the pressure plate slightly presses the upper cover plate, so that the axis of the upper cover plate is in the correct position, so that the upper cover plate can be returned to the correct position later, thereby positioning the upper cover plate, the control arm, and the connecting block. Figure 8As shown, the servo motor drives the displacement member to move right, and the mounting portion of the displacement member moves right with the return assembly, and the push block on the telescopic rod contacts the side of the upper cover that can only rotate and returns the upper cover (the staff will basically deflect a little when placing the upper cover), and the push block presses the side of the upper cover under the action of the first elastic member, and maintains the side pressure in the subsequent process, thereby positioning the upper cover, as shown in FIG. Fig. 9 As shown, the displacement member continues to move right, and the side push block of the displacement member pushes the slider to move right along the slide groove and the slide rod, and the slider moves right with the first welding gun, and the first welding gun performs transverse welding on the inner side of the connecting block and the control arm, and the slider and the first welding gun move right to the bottom, and at the same time, part of the teeth of the displacement member mesh with the locking gear, and the locking gear rotates with the second large gear through the first large gear and the small gear, and the second large gear drives the gear ring to rotate, and the gear ring rotates with the two fixed columns and the second welding gun, and the second welding gun performs arc welding on the outer ring of the upper cover plate and the upper end surface of the control arm, and the welding of the connecting block and the upper cover plate is completed, as shown in FIG. Fig.10 As shown, the servo motor drives the displacement member to move the return assembly to the left and reset, and the slider and the first welding gun move to the left and reset under the action of the second elastic member. At the same time, some teeth of the displacement member drive the gear ring and the second welding gun to reverse and reset, and then some teeth disengage from the locking gear, and the locking gear is locked by the horizontal bar of the displacement member. Then the cylinder drives the plate to move the components upward and reset.

[0027] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A welding device for a rear lower control arm of an automobile, characterized in that: The invention comprises a base, wherein the upper end of the base is provided with a bracket and a side positioning block for positioning the connecting block, the upper end of the base is elastically and telescopically provided with two lower positioning columns for positioning the control arm, the top end of the bracket is provided with a cylinder downwardly, the piston rod end of the cylinder is laterally provided with a plate, the left and right sides of the lower end of the plate are respectively connected with a left connecting column and a right connecting column, the end of the right connecting column is connected with a positioning member for positioning the upper cover plate and the control arm, the left connecting column is connected with an inner transverse welding assembly, the inner transverse welding assembly is slidably provided with a displacement member driven by a servo motor for moving left and right, the plate and the right connecting column are provided with an outer arc welding assembly, the bottom of the displacement member is provided with a return assembly, and during the process of the displacement member moving right, the displacement member first causes the return assembly to return the upper cover plate, and the displacement member then drives the inner transverse welding assembly and the outer arc welding assembly to weld the connecting block and the upper cover plate respectively.

2. The welding device for the rear lower control arm of an automobile as claimed in claim 1, characterized in that: The positioning member is composed of a middle positioning plate connected to an upper pressure plate and an upper positioning column at a lower side. The lower edge of the positioning plate is provided with a rounded corner. The upper positioning column corresponds to the lower positioning column up and down.

3. The welding device for a rear lower control arm of an automobile as claimed in claim 1, characterized in that: The displacement member is composed of a middle horizontal bar connecting the side thrust parts and the mounting parts on the left and right sides. A rack is laterally arranged on the rear side of the upper end of the horizontal bar. A driving gear meshing with the rack is keyed on the output shaft of the servo motor. Partial teeth are laterally arranged on the front end of the horizontal bar, and an avoidance groove is opened on the left side of the front end of the horizontal bar.

4. The welding device for the rear lower control arm of an automobile as claimed in claim 3, characterized in that: The return assembly includes a fixed tube transversely arranged at the lower end of the erection part, a telescopic groove is transversely opened in the fixed tube, a telescopic rod is slidably fitted in the telescopic groove, a first elastic member connecting the telescopic rod and the telescopic groove is arranged in the telescopic groove, and a push block is longitudinally arranged at the end of the telescopic rod.

5. The automobile rear lower control arm welding device as claimed in claim 3, characterized in that: The inner horizontal welding assembly includes a fixing plate horizontally connected to the left connecting column, and sliding holes are horizontally and symmetrically opened on the front and rear sides of the upper end of the fixing plate. A sliding rod is horizontally arranged in the sliding hole, and a sliding block that can be pushed sideways by the side pushing part is slidably arranged at the sliding hole and the sliding rod. A second elastic member connecting the sliding hole and the sliding block is arranged on the outer sleeve of the sliding bar, and a first welding gun is arranged at the bottom of the sliding block.

6. The welding device for the rear lower control arm of an automobile as claimed in claim 5, characterized in that: The first welding gun is locked to the bottom of the sliding block in an inclined manner inwardly by a first locking bolt.

7. The welding device for a rear lower control arm of an automobile as claimed in claim 5, characterized in that: A guide block for slidingly fitting the horizontal bar and the rack is arranged at the rear end of the fixing plate.

8. The automobile rear lower control arm welding device as claimed in claim 3, characterized in that: The outer arc welding assembly includes a locking gear rotating under the flat plate, the locking gear can be locked by the horizontal bar and cooperate with the partial teeth, a first large gear is coaxially connected to the top of the locking gear, a small gear is meshed at the right end of the first large gear, a second large gear is coaxially connected to the top of the small gear, a gear ring meshing with the second large gear is rotatably provided at the upper end of the right connecting column, two fixing columns are evenly distributed on the gear ring along the circumference of its axis, and a second welding gun is provided at the bottom of the fixing column.

9. The welding device for the rear lower control arm of an automobile as claimed in claim 8, characterized in that: The second welding gun is locked to the bottom of the fixing column in an oblique manner outwardly through a second locking bolt, and the second welding gun intersects with the axis of the gear ring.

10. The automobile rear lower control arm welding device according to claim 1, characterized in that: Guide rods are vertically and symmetrically arranged on the left and right sides of the upper end of the flat plate, and the guide rods are slidably matched with the bracket so as to move up and down.

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