Automatic axial alignment flange pipeline butt welding clamp and using method thereof

Abstract

The invention belongs to the technical field of welding clamps, and discloses an automatic axial alignment flange pipeline butt welding clamp and a using method thereof, and the automatic axial alignment flange pipeline butt welding clamp comprises a rack, a three-jaw chuck, a chuck rotating shaft, a gear motor, a small belt wheel, a large belt wheel, a sliding rail and a motor support; the large belt wheel is installed at the rear end of the chuck rotating shaft in a key connection mode, a synchronous belt is rotationally connected between the large belt wheel and the small belt wheel, and the method further comprises the following steps that zero setting is conducted, and the upper sliding block and the lower sliding block are adjusted to be in a closed state. The pipeline can be firmly clamped by simply rotating the hand wheel, particularly, when the pipeline is clamped, the axis of the pipeline can be automatically and accurately aligned with the axis of the flange, the characteristic reduces tedious adjusting steps, the four roller way bodies capable of freely rotating are used for clamping the pipeline in the assembling process, and the assembling efficiency is improved. And uniform and balanced stress of the pipeline is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of welding fixtures, and in particular relates to an automatic axial alignment flange pipeline butt welding fixture and a use method thereof. Background Art

[0002] Welding fixtures play a vital role in the manufacturing industry. They not only ensure the accurate and reliable positioning and clamping of the workpiece during the welding process, but are also the key factors in reducing product size deviations and improving part accuracy and interchangeability. Through precise design and manufacturing, welding fixtures can effectively prevent and reduce possible deformation during welding, so that the workpiece is always kept in the most suitable welding position, thereby greatly improving the speed and efficiency of welding operations. The application of this technology not only significantly improves the quality stability of welding products, but also effectively reduces the labor intensity of operators. It is an indispensable part of modern welding production.

[0003] In the field of flange pipe welding, the subdivision of welding fixtures is particularly critical, mainly including assembly fixtures, welding fixtures, and assembly-welding fixtures that integrate the functions of both. Although assembly fixtures and welding fixtures each play a role in their respective dedicated fields, the singleness of their functions limits the optimization space of the overall production process. In contrast, assembly-welding fixtures are designed to improve production efficiency by integrating the dual functions of assembly and welding. However, assembly-welding fixtures in the prior art generally face the problem of insufficient assembly accuracy. In actual operation, the process of adjusting the position of the weldment is often complicated and cumbersome, which not only increases the difficulty and time cost of the operation, but also inevitably leads to the aggravation of welding deformation, which in turn seriously affects the quality of the welded product. In addition, these defects also directly lead to low welding efficiency, becoming an important bottleneck restricting the improvement of production efficiency and product quality. Summary of the invention

[0004] The object of the present invention is to provide an automatic axial alignment flange pipe butt welding fixture and a use method thereof to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: an automatic axial alignment flange pipe butt welding fixture, comprising a frame, a three-jaw chuck, a chuck shaft, a reduction motor, a small pulley, a large pulley, a slide rail and a motor support;

[0006] The large pulley is installed at the rear end of the chuck shaft through a key connection, a synchronous belt is rotatably connected between the large pulley and the small pulley, the small pulley is connected to the output shaft of the reduction motor, the reduction motor is horizontally fixedly connected to the motor support, and the front end face axis of the chuck shaft is connected to the three-jaw chuck;

[0007] There are two slide rails in total, and the two slide rails are symmetrically fixedly connected to the frame. A slider is arranged inside the dovetail groove of the slide rail, and the slider is slidably connected to the slide rail.

[0008] Preferably, the frame includes an L-shaped bracket, a chuck bracket and a load-bearing bracket;

[0009] The L-shaped bracket is fixedly mounted on one end of the load-bearing bracket, the chuck frame is fixedly mounted on the other end of the load-bearing bracket, and the motor support is mounted flush with the rear end outer corner of the chuck frame.

[0010] Preferably, the rack also includes a corner seat, a screw and a foot pad, the corner seat is symmetrically installed at the four corners of the lower end of the load-bearing bracket, the screw vertically passes through the central screw hole of the corner seat, and the screw is screwed together with the corner seat, the foot pad is fixedly installed at the bottom end of the screw, and the lower surface of the foot pad is in contact with the ground.

[0011] Preferably, a lower support plate is provided above the chuck frame, and the top surface of the chuck frame and the bottom surface of the groove are in contact with the lower support plate, and the two ends of the lower support plate are aligned with the two ends of the chuck frame and fixedly connected with the lower support plate by bolts;

[0012] The upper surface of the lower support plate is aligned and fixedly connected with an upper cover plate, and two bearings are symmetrically arranged inside the upper cover plate and the lower support plate. One end of the chuck shaft passes through the two bearings to form a rotating mechanism, and the other end is connected to the three-jaw chuck.

[0013] Preferably, it further comprises a support plate, the sliders comprise two groups, one upper group and one lower group, and each group of the sliders is fixedly connected to the left and right vertical angles of the support plate;

[0014] There are two support plates in total, and the two support plates are symmetrically arranged in the upper and lower parts, a roller body support is arranged between the two support plates, and there are four roller body supports in total, and the four roller body supports are divided into two groups symmetrical in the upper and lower parts, each group of the roller body supports is symmetrically arranged in the left and right parts, each group of the roller body supports is flush with the left and right end surfaces of the support plates, and the roller body supports are fixedly connected to the support plates by bolts, a roller body rotating shaft is arranged inside the roller body support, and there are four roller body rotating shafts in total, the through holes at the upper ends of the roller body supports are aligned with the roller body rotating shafts and are locked by nuts, a roller body is arranged on the roller body rotating shaft, and the roller body is horizontally arranged.

[0015] Preferably, a bearing seat is arranged between the two slide rails, and there are two bearing seats in total. The two bearing seats are symmetrically arranged up and down, and are respectively vertically fixed on the upper and lower beams at the vertical ends of the L-shaped bracket. A vertical rotating shaft is rotatably connected between the two bearing seats.

[0016] Preferably, an upper rotating shaft sleeve and a lower rotating shaft sleeve are vertically and symmetrically fixedly connected on one side of the L-shaped bracket, the upper rotating shaft sleeve is located above the lower rotating shaft sleeve, and the upper rotating shaft sleeve and the lower rotating shaft sleeve are located between two bearing seats, the rotating shaft passes through the screw holes on the upper rotating shaft sleeve and the lower rotating shaft sleeve, and the top end of the rotating shaft is fixedly connected to a handwheel through a spline groove, the upper rotating shaft sleeve and the lower rotating shaft sleeve have the same shape, the center screw hole is a reverse thread, and a support plate is fixedly connected to the upper rotating shaft sleeve and the lower rotating shaft sleeve and the L-shaped bracket by bolts.

[0017] Preferably, the L-shaped bracket and the chuck frame are both formed by welding rectangular tubes, and the load-bearing bracket is formed by welding equilateral angle steels.

[0018] A method for using the automatic axial alignment flange pipe butt welding fixture comprises the following steps:

[0019] S1: Zero adjustment, adjust the upper and lower sliders to the close state, and make the dividing line between the upper and lower sliders coincide with the zero scale line on the surface of the slide rail, and complete the zero adjustment operation. At this time, the upper and lower roller bodies are tangent, and the central axis of the roller body group is aligned with the axis of the three-jaw chuck;

[0020] S2: Fix the butt welding flange to the three-jaw chuck;

[0021] S3: Turn the hand wheel to make the upper and lower support plates move in opposite directions, drive the upper and lower roller bodies to separate, place the pipeline horizontally between the upper and lower support plates, and turn the hand wheel in the opposite direction so that the four roller bodies clamp the pipeline in the middle, and adjust the horizontal position of the pipeline so that the distance between the welding joint of the butt-welding flange and the welding joint of the pipeline is adjusted;

[0022] S4: Use an electric welder to spot weld the welds between the butt-welded flange and the pipe, start the reduction motor, drive the three-jaw chuck to rotate slowly through the transmission, and use the manual electric welder or welding robot to perform full welding again.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] In the weldment assembly process, the present invention only needs to manually fine-tune the distance between the pipe and the flange to control the distance, and then simply turn the hand wheel to achieve firm clamping of the pipe. It is particularly worth mentioning that when the pipe is clamped, its axis and the flange axis can be automatically and accurately aligned. This feature reduces the cumbersome adjustment steps. In addition, the assembly process uses four freely rotatable roller bodies to clamp the pipe, which not only ensures the uniform balance of force on the pipe, but also significantly reduces the deformation that may occur during welding due to the effective extension of the clamping section. Compared with traditional integrated welding fixtures, this new fixture is lightweight in weight, making it more convenient to carry and move. This improvement not only improves the flexibility of operation, but also significantly improves the efficiency of welding operations and the quality of welded products through its efficient application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is one of the invented stereograms;

[0026] Figure 2 It is the second of the invented stereograms;

[0027] Figure 3 It is a top view of the invention with the upper cover removed;

[0028] Figure 4 It is a three-dimensional diagram of the invention when the load-bearing bracket, the chuck bracket and the L-shaped bracket are connected;

[0029] Figure 5 is a three-dimensional diagram of the invented support plate;

[0030] Figure 6 It is a three-dimensional diagram of the invention of the slide;

[0031] Figure 7 yes Figure 6 Enlarged view of part A in the middle;

[0032] Figure 8 It is a three-dimensional diagram of the invented roller body support;

[0033] Fig. 9 It is a stereogram of the invented slider;

[0034] In the figure: 101, small pulley; 102, motor support; 103, synchronous belt; 104, reduction motor; 105, chuck shaft; 106, three-jaw chuck; 107, L-shaped bracket; 108, handwheel; 109, slide rail; 110, bearing seat; 111, shaft; 112, upper rotating shaft sleeve; 113, support plate; 114, roller body; 115, roller body support; 116, angle seat; 117, screw; 118, foot pad; 119, roller body shaft; 120, pipeline; 121, lower bearing plate; 122, chuck frame; 123, upper cover plate; 124, large pulley; 125, load-bearing bracket; 126, butt welding flange; 127, lower rotating shaft sleeve; 128, slider; 129, bearing. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] See also Figure 1-Figure 9 As shown, the present invention provides the following technical solutions:

[0037] An automatic axial alignment flange pipe butt welding fixture comprises a frame, a three-jaw chuck 106, a chuck shaft 105, a reduction motor 104, a small pulley 101, a large pulley 124, a slide rail 109 and a motor support 102;

[0038] The large pulley 124 is installed at the rear end of the chuck shaft 105 through a key connection, and a synchronous belt 103 is rotatably connected between the large pulley 124 and the small pulley 101. The small pulley 101 is connected to the output shaft of the reduction motor 104, and the reduction motor 104 is horizontally fixedly connected to the motor support 102. The front end face axis of the chuck shaft 105 is connected to the three-jaw chuck 106;

[0039] There are two slide rails 109 in total, and the two slide rails 109 are symmetrically fixedly connected to the frame. A slider 128 is arranged inside the dovetail groove of the slide rail 109, and the slider 128 is slidably connected to the slide rail 109.

[0040] Through the above technical solution, the device is moved to the point of use, supported by the frame for other structures, and zeroed until the upper and lower sets of sliders 128 are close together, and the dividing line between the upper and lower sliders 128 coincides with the zero scale line on the surface of the slide rail 109. The zeroing operation can be completed, the processed material is fixed on the three-jaw chuck 106, the reduction motor 104 is started, and the three-jaw chuck 106 is driven to rotate slowly through the transmission, and the manual electric welder or welding robot is used again to perform full welding operations.

[0041] Specifically, in one embodiment, regarding the above-mentioned rack, as Figure 1-Figure 4 As shown, the frame includes an L-shaped bracket 107, a chuck bracket 122 and a load-bearing bracket 125;

[0042] The L-shaped bracket 107 is fixedly mounted on one end of the load-bearing bracket 125 , the chuck frame 122 is fixedly mounted on the other end of the load-bearing bracket 125 , and the motor support 102 is installed flush with the rear end outer corner of the chuck frame 122 .

[0043] In this embodiment, when the device is in use, the L-shaped bracket 107 and the chuck frame 122 are supported by the load-bearing bracket 125, the motor support 102 is supported by the chuck frame 122, the reduction motor 104 is supported by the motor support 102, and the slide rail 109 is supported by the L-shaped bracket 107. The zero adjustment operation can be completed by adjusting the upper and lower groups of sliders 128 to be close together and making the dividing line between the upper and lower sliders 128 coincide with the zero scale line on the surface of the slide rail 109.

[0044] Furthermore, when personnel place the device, in order to further improve the stability of the device after placement, such as Figure 1-Figure 2As shown, the rack also includes an angle seat 116, a screw rod 117 and a foot pad 118. The angle seat 116 is symmetrically installed at the four corners of the lower end of the load-bearing bracket 125. The screw rod 117 vertically passes through the central screw hole of the angle seat 116, and the screw rod 117 is screwed together with the angle seat 116. The foot pad 118 is fixedly installed at the bottom end of the screw rod 117, and the lower surface of the foot pad 118 is in contact with the ground.

[0045] In this embodiment, when the device is in use, the L-shaped bracket 107 and the chuck frame 122 are supported by the load-bearing bracket 125, the motor support 102 is supported by the chuck frame 122, the reduction motor 104 is supported by the motor support 102, and the slide rail 109 is supported by the L-shaped bracket 107. The zero adjustment operation can be completed by adjusting the upper and lower groups of sliders 128 to be close together and making the dividing line between the upper and lower sliders 128 coincide with the zero scale line on the surface of the slide rail 109.

[0046] Furthermore, in the present invention, in order to stably support the large pulley 124, as Figure 1-Figure 3 As shown, a lower support plate 121 is provided above the chuck frame 122, and the top surface and the bottom surface of the groove on the chuck frame 122 are in contact with the lower support plate 121, and the two ends of the lower support plate 121 are aligned with the two ends of the chuck frame 122 and are fixedly connected to the lower support plate 121 by bolts;

[0047] The upper surface of the lower support plate 121 is aligned and fixedly connected with an upper cover plate 123 , and two bearings 129 are symmetrically arranged inside the upper cover plate 123 and the lower support plate 121 . One end of the chuck shaft 105 passes through the two bearings 129 to form a rotating mechanism, and the other end is connected to the three-jaw chuck 106 .

[0048] In this embodiment, when the device is in use, the L-shaped bracket 107 and the chuck frame 122 are supported by the load-bearing bracket 125, the motor support 102 is supported by the chuck frame 122, the reduction motor 104 is supported by the motor support 102, the slide rail 109 is supported by the L-shaped bracket 107, and the large pulley 124 is supported by the upper cover plate 123, and the chuck shaft 105 is supported by the large pulley 124, so as to support the three-jaw chuck 106, and the zeroing work is performed to adjust the upper and lower The two sets of sliders 128 are brought together, and the dividing line between the upper and lower sliders 128 coincides with the zero scale line on the surface of the slide rail 109 to complete the zero adjustment operation. The processing material is fixed on the three-jaw chuck 106, and the reduction motor 104 is started. The small pulley 101 is driven to rotate by the reduction motor 104, and the large pulley 124 is driven to rotate through the cooperation of the small pulley 101 and the transmission belt. The three-jaw chuck 106 is driven to rotate slowly through the cooperation of the chuck shaft 105, and the full welding operation is performed again using the manual electric welder or the welding robot.

[0049] In addition, in the present invention, in order to support one end of the pipe 120, the clamp further includes a support plate 113, and the slider 128 includes two groups, upper and lower, and each group of sliders 128 is fixedly connected to the left and right vertical angles of the support plate 113;

[0050] There are two support plates 113 in total, and the two support plates 113 are symmetrically arranged up and down, a roller body support 115 is arranged between the two support plates 113, and there are four roller body supports 115 in total, and the four roller body supports 115 are divided into two groups that are symmetrical up and down, each group of roller body supports 115 is symmetrically arranged left and right, each group of roller body supports 115 is flush with the left and right end surfaces of the support plate 113, and the roller body supports 115 are fixedly connected to the support plate 113 by bolts, a roller body rotating shaft 119 is arranged inside the roller body support 115, and there are four roller body rotating shafts 119 in total, the through hole at the upper end of the roller body support 115 is aligned with the roller body rotating shaft 119 axis, and is locked by a nut, a roller body 114 is arranged on the roller body rotating shaft 119, and the roller body 114 is horizontally arranged.

[0051] In this embodiment, zero adjustment is performed by pulling the two groups of sliders 128 and cooperating with the slide rail 109 to move the two groups of sliders 128 until the upper and lower groups of sliders 128 are close together and the dividing line between the upper and lower sliders 128 coincides with the zero scale line on the surface of the slide rail 109. The zero adjustment operation is completed. At this time, the upper and lower roller bodies 114 are tangent to each other, and the central axis of the roller body 114 group is aligned with the axis of the three-jaw chuck 106.

[0052] Furthermore, in the present invention, in order to facilitate the adjustment of the slider 128, a bearing seat 110 is provided between the two slide rails 109, and there are two bearing seats 110 in total, and the two bearing seats 110 are symmetrically arranged up and down, and are respectively vertically fixed on the upper and lower beams at the vertical end of the L-shaped bracket 107, and a vertical rotating shaft 111 is rotatably connected between the two bearing seats 110, and an upper rotating shaft sleeve 112 and a lower rotating shaft sleeve 127 are vertically and symmetrically fixedly connected to one side of the L-shaped bracket 107, and the upper rotating shaft sleeve 112 is located above the lower rotating shaft sleeve 127, and the upper rotating shaft sleeve 112 and the lower rotating shaft sleeve 127 are located between the two bearing seats 110, and the rotating shaft 111 passes through the upper rotating shaft sleeve 112 and the lower rotating shaft sleeve 127. The screw hole of the rotating shaft 111 is fixedly connected with the hand wheel 108 through the spline groove. The upper rotating shaft sleeve 112 has the same shape as the lower rotating shaft sleeve 127, and the center screw hole is a reverse thread. The upper rotating shaft sleeve 112 and the lower rotating shaft sleeve 127 are fixedly connected with the L-shaped bracket 107 by bolts. When the position of the slider 128 needs to be adjusted, the vertical rotating shaft 111 is rotated, and the bearing seat 110 is matched, and the upper rotating shaft sleeve 112 and the lower rotating shaft sleeve 127 are matched. Since the upper rotating shaft sleeve 112 and the lower rotating shaft sleeve 127 have the same shape and the center screw hole is a reverse thread, the two support plates 113 are moved relative to each other, thereby adjusting the distance between the two support plates 113.

[0053] The L-shaped bracket 107 and the chuck frame 122 are both formed by welding rectangular tubes, and the load-bearing bracket 125 is formed by welding equilateral angle steels.

[0054] A method for using an automatic axial alignment flange pipe butt welding fixture comprises the following steps:

[0055] S1: Zero adjustment, adjust the upper and lower sliders 128 to a close state, and make the boundary line of the upper and lower sliders 128 coincide with the zero scale line on the surface of the slide rail 109, and complete the zero adjustment operation. At this time, the upper and lower roller bodies 114 are tangent, and the central axis of the roller body 114 group is aligned with the axis of the three-jaw chuck 106;

[0056] S2: Fix the butt welding flange 126 to the three-jaw chuck 106;

[0057] S3: Turn the hand wheel 108 to make the upper and lower support plates 113 move in the opposite direction, drive the upper and lower roller bodies 114 to separate, place the pipeline 120 horizontally between the upper and lower support plates 113, and turn the hand wheel 108 in the opposite direction to make the four roller bodies 114 sandwich the pipeline 120, and adjust the horizontal position of the pipeline 120 to adjust the distance between the welding joint of the welding flange 126 and the welding joint of the pipeline 120;

[0058] S4: Use an electric welder to spot weld the weld joint between the butt-welding flange 126 and the pipeline 120, start the reduction motor 104, drive the three-jaw chuck 106 to rotate slowly through the transmission, and use the manual electric welder or welding robot again to perform full welding operation.

[0059] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An automatic axial alignment flange pipe butt welding fixture, characterized by: It comprises a frame, a three-jaw chuck (106), a chuck rotating shaft (105), a reduction motor (104), a small pulley (101), a large pulley (124), a slide rail (109) and a motor support (102); The large pulley (124) is installed on the rear end of the chuck shaft (105) through a key connection, a synchronous belt (103) is rotatably connected between the large pulley (124) and the small pulley (101), the small pulley (101) is connected to the output shaft of the reduction motor (104), the reduction motor (104) is horizontally fixedly connected to the motor support (102), and the front end face axis of the chuck shaft (105) is connected to the three-jaw chuck (106); There are two slide rails (109) in total, and the two slide rails (109) are symmetrically fixedly connected to the frame. A slider (128) is arranged inside the dovetail groove of the slide rail (109), and the slider (128) is slidably connected to the slide rail (109).

2. The automatic axial alignment flange pipe butt welding fixture according to claim 1 is characterized by: The frame comprises an L-shaped bracket (107), a chuck bracket (122) and a load-bearing bracket (125); The L-shaped bracket (107) is fixedly mounted on one end of the load-bearing bracket (125), the chuck frame (122) is fixedly mounted on the other end of the load-bearing bracket (125), and the motor support (102) is installed flush with the outer corner of the rear end of the chuck frame (122).

3. The automatic axial alignment flange pipe butt welding fixture according to claim 2 is characterized by: The frame also includes an angle seat (116), a screw rod (117) and a foot pad (118), wherein the angle seat (116) is symmetrically mounted at the four corners of the lower end of the load-bearing bracket (125), the screw rod (117) vertically passes through the central screw hole of the angle seat (116), and the screw rod (117) is screwed and connected to the angle seat (116), and the foot pad (118) is fixedly mounted at the bottom end of the screw rod (117), and the lower surface of the foot pad (118) is in contact with the ground.

4. The automatic axial alignment flange pipe butt welding fixture according to claim 2 or 3, characterized in that: A lower support plate (121) is arranged above the chuck frame (122), and the top surface and the bottom surface of the groove on the chuck frame (122) are in contact with the lower support plate (121), and two ends of the lower support plate (121) are aligned with two ends of the chuck frame (122) and are fixedly connected to the lower support plate (121) by bolts; The upper surface of the lower support plate (121) is aligned and fixedly connected with an upper cover plate (123); two bearings (129) are symmetrically arranged inside the upper cover plate (123) and the lower support plate (121); one end of the chuck shaft (105) passes through the two bearings (129) to form a rotating mechanism, and the other end is connected to the three-jaw chuck (106).

5. The automatic axial alignment flange pipe butt welding fixture according to claim 4 is characterized by: It also includes a support plate (113), wherein the sliders (128) include two groups, an upper group and an lower group, and each group of the sliders (128) is fixedly connected to the left and right vertical angles of the support plate (113); There are two support plates (113) in total, and the two support plates (113) are symmetrically arranged in the upper and lower parts. A roller body support (115) is arranged between the two support plates (113). There are four roller body supports (115) in total, and the four roller body supports (115) are divided into two groups symmetrical in the upper and lower parts. Each group of roller body supports (115) is symmetrically arranged in the left and right parts. Each group of roller body supports (115) is flush with the left and right end surfaces of the support plate (113). The roller body support (115) is fixedly connected to the support plate (113) by bolts; a roller body rotating shaft (119) is arranged inside the roller body support (115); there are four roller body rotating shafts (119); the through hole at the upper end of the roller body support (115) is aligned with the roller body rotating shaft (119) and locked by a nut; a roller body (114) is arranged on the roller body rotating shaft (119); and the roller body (114) is arranged horizontally.

6. The automatic axial alignment flange pipe butt welding fixture according to claim 5 is characterized by: A bearing seat (110) is arranged between the two slide rails (109), and there are two bearing seats (110) in total. The two bearing seats (110) are symmetrically arranged up and down and are respectively vertically fixed on the upper and lower beams at the vertical ends of the L-shaped bracket (107). A vertical rotating shaft (111) is rotatably connected between the two bearing seats (110).

7. The automatic axial alignment flange pipe butt welding fixture according to claim 6 is characterized by: An upper rotating shaft sleeve (112) and a lower rotating shaft sleeve (127) are vertically and symmetrically fixedly connected on one side of the L-shaped bracket (107); the upper rotating shaft sleeve (112) is located above the lower rotating shaft sleeve (127), and the upper rotating shaft sleeve (112) and the lower rotating shaft sleeve (127) are located between two bearing seats (110); the rotating shaft (111) passes through the screw holes on the upper rotating shaft sleeve (112) and the lower rotating shaft sleeve (127), and the top of the rotating shaft (111) is fixedly connected to a hand wheel (108) via a spline groove; the upper rotating shaft sleeve (112) and the lower rotating shaft sleeve (127) have the same appearance, and the central screw hole is a reverse thread; and a support plate (113) is fixedly connected between the upper rotating shaft sleeve (112) and the lower rotating shaft sleeve (127) and the L-shaped bracket (107) via bolts.

8. The automatic axial alignment flange pipe butt welding fixture according to claim 2 is characterized by: The L-shaped bracket (107) and the chuck frame (122) are both formed by welding rectangular tubes, and the load-bearing bracket (125) is formed by welding equilateral angle steels.

9. A method for using the automatic axial alignment flange pipe butt welding fixture according to any one of claims 1 to 8, characterized in that: The steps include: S1: Zero adjustment, adjust the upper and lower sliders (128) to a close state, and make the boundary line of the upper and lower sliders (128) coincide with the zero scale line on the surface of the slide rail (109), and complete the zero adjustment operation. At this time, the upper and lower roller bodies (114) are tangent, and the central axis of the roller body (114) group is aligned with the axis of the three-jaw chuck (106); S2: Fix the butt welding flange (126) to the three-jaw chuck (106); S3: Turn the hand wheel (108) to make the upper and lower support plates (113) move in opposite directions, drive the upper and lower roller bodies (114) to separate, and place the pipeline (120) horizontally between the upper and lower support plates (113). Then, turn the hand wheel (108) in the opposite direction to make the four roller bodies (114) sandwich the pipeline (120) in the middle, and adjust the horizontal position of the pipeline (120) so that the distance between the weld joint of the butt-weld flange (126) and the weld joint of the pipeline (120) is adjusted. S4: Use an electric welder to spot weld the weld joint between the butt-welding flange (126) and the pipe (120), start the reduction motor (104), drive the three-jaw chuck (106) to rotate slowly through the transmission, and use the manual electric welder or welding robot to perform full welding again.

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