A welding device and method for high-efficiency and high-quality welding of double oil pipe short sections

Abstract

The present invention discloses a welding device and method for welding double oil pipe short sections with high efficiency and high quality. The present invention relates to the technical field of welding large-size oil pipe short sections and small-size oil pipe short sections. The device comprises a workbench, on which a grabbing mechanism for grabbing a large-size oil pipe short section, an ejecting mechanism for ejecting a large-size oil pipe short section, and an inserting mechanism for tooling and pushing a small-size oil pipe short section are arranged in sequence from left to right. The grabbing mechanism is provided with a welding and rolling mechanism. The present invention has the beneficial effects of greatly improving the welding efficiency of large-size oil pipe short sections and small-size oil pipe short sections, and greatly improving the welding quality of large-size oil pipe short sections and small-size oil pipe short sections.

Description

Technical Field

[0001] The invention relates to the technical field of welding a large-size oil pipe pup joint and a small-size oil pipe pup joint, and in particular to a welding device and method for welding double oil pipe pup joints with high efficiency and high quality. Background Art

[0002] The welding process of double oil pipe short joints is to use a laser welding machine to weld Figure 1 The large size tubing nipple 1 shown is similar to the Figure 2 The small size tubing nipples 2 shown are welded together to obtain Figure 3~Figure 4 In the product A shown, the outer diameter of the small-sized tubing nipple 2 is larger than the inner diameter of the large-sized tubing nipple 1. This product is mainly installed between two valves to realize the transmission of fluid.

[0003] In the workshop, the method of welding the large-size tubing nipple 1 and the small-size tubing nipple 2 together is:

[0004] S1. The worker takes out the large-size tubing nipple 1 and the small-size tubing nipple 2 from the material basket, and fixes the large-size tubing nipple 1 on the machine table of the press by means of a fixture;

[0005] S2. The worker pre-inserts the left end of the small-sized tubing nipple 2 into the right port of the large-sized tubing nipple 1, and then controls the piston rod of the press to extend to the left. The piston rod drives the press head to move to the left, and the press head pushes the small-sized tubing nipple 2 to the left. Under the push of the press head, the left end of the small-sized tubing nipple 2 is gradually pushed into the right port of the large-sized tubing nipple 1. When the insertion is in place, the large-sized tubing nipple 1 and the small-sized tubing nipple 2 form an interference fit.

[0006] S3. The worker opens the fixture and then removes the large-size tubing nipple 1 and the small-size tubing nipple 2 that are interference-fitted from the machine. After removing them, the worker fixes the left end of the large-size tubing nipple 1 on the three-jaw chuck of the machine tool. Figure 5 As shown;

[0007] S4, control the power system of the machine tool to start, the power system drives the three-jaw chuck to rotate, the three-jaw chuck drives the large-size oil pipe short section 1 to rotate synchronously, the large-size oil pipe short section 1 drives the small-size oil pipe short section 2 to rotate synchronously, the rotation direction is as follows Figure 5 As indicated by the arrow;

[0008] S5. The worker aligns the welding head 3 of the laser welding machine with the right end of the large-size oil pipe short section 1. Figure 6As shown, the laser welding machine is then started, and the laser beam emitted downward by the welding head 3 acts on the right end of the large-size oil pipe nipple 1. When the large-size oil pipe nipple 1 rotates one circle, the laser beam forms a circle of annular weld scar 4 on the outer surface of the right end of the large-size oil pipe nipple 1. At the same time, the large-size oil pipe nipple 1 and the small-size oil pipe nipple 2 are welded together, and then the first product A is produced by welding.

[0009] S6. The worker repeats steps S1 to S5 for multiple times, and then continuously welds and produces multiple products A.

[0010] However, although the method used in the workshop can weld the large-size tubing nipple 1 and the small-size tubing nipple 2 together to produce product A, it still has the following technical defects:

[0011] I. Among them, in steps S2 to S5, after the small-size tubing nipple 2 is inserted into the large-size tubing nipple 1, the worker needs to first open the jig to remove the large-size tubing nipple 1 and the small-size tubing nipple 2 that are interference-fitted together; then fix the left end of the large-size tubing nipple 1 on the three-jaw chuck of the machine tool; then align the welding head 3 of the laser welding machine with the right end of the large-size tubing nipple 1 to complete the welding of the large-size tubing nipple 1 and the small-size tubing nipple 2; and the entire operation is completed manually, which not only increases the work intensity of the workers, but also increases the production time of a single product A, thereby reducing the welding efficiency.

[0012] II. Although the welded product A can be used, during use, if the small-size tubing nipple 2 is subjected to external axial force, the small-size tubing nipple 2 is easy to be detached from the large-size tubing nipple 1, thereby causing leakage of the fluid flowing in the large-size tubing nipple 1; therefore, the welding method used in the workshop has a technical defect of low welding quality.

[0013] Therefore, there is an urgent need for a welding device and method that can greatly improve the welding efficiency and quality of large-size oil pipe pup joints and small-size oil pipe pup joints. Summary of the invention

[0014] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a welding device and method for welding double oil pipe pup joints with high efficiency and high quality, which greatly improves the welding efficiency and welding quality of large-sized oil pipe pup joints and small-sized oil pipe pup joints.

[0015] The object of the present invention is achieved through the following technical solutions: A welding device for welding double oil pipe short sections with high efficiency and high quality, comprising a workbench, on which a grabbing mechanism for grabbing a large-size oil pipe short section, an ejecting mechanism for ejecting a large-size oil pipe short section, and an inserting mechanism for tooling and pushing a small-size oil pipe short section are arranged in sequence from left to right, and a welding and rolling mechanism is arranged on the grabbing mechanism;

[0016] The grabbing mechanism comprises a vertical plate fixed on the workbench, a first driving motor fixed on the left end surface of the vertical plate, and a horizontal oil cylinder fixed on the top surface of the vertical plate, the output shaft of the first driving motor penetrates the vertical plate to the right, and a rotating plate is fixed on the extended end, a vertical oil cylinder is fixed on the right end surface of the rotating plate, the piston rod of the vertical oil cylinder extends downward, and a mounting plate is fixed on the extended end, a plurality of clamping oil cylinders are fixed on the bottom surface of the mounting plate, and the clamping heads of the clamping oil cylinders are arranged downward; the piston rod of the horizontal oil cylinder extends to the right, and a second driving motor is fixed on the extended end, and a three-jaw chuck with an opening facing right is connected to the output shaft of the second driving motor;

[0017] The welding and rolling mechanism includes a connecting frame fixedly arranged on the top surface of the vertical plate, the connecting frame extends to the right on the right side of the vertical plate, and a third drive motor is fixedly arranged on the top surface of the extended end, the output shaft of the third drive motor passes downward through the connecting frame, and a turntable is fixedly arranged on the extended end, the left end of the turntable is fixedly connected to the welding head of the laser welding machine, a rolling cylinder is fixedly arranged on the top surface of the right end of the turntable, the piston rod of the rolling cylinder passes downward through the turntable, and a U-shaped frame is fixedly connected to the extended end, a main shaft is rotatably installed in the U-shaped frame, two rolling wheels arranged at intervals are fixedly arranged on the main shaft, a rolling motor is fixedly arranged on the left end surface of the U-shaped frame, and the output shaft of the rolling motor is connected to the main shaft.

[0018] A plurality of support frames are fixedly arranged on the bottom surface of the workbench, and the support frames are supported on the ground.

[0019] The ejection mechanism includes a barrel fixedly mounted on the workbench and an ejection oil cylinder fixedly mounted on the bottom surface of the workbench. The inner cavity of the barrel matches the outer contour of a large-size oil pipe short section. The piston rod of the ejection oil cylinder sequentially penetrates the workbench and the bottom wall of the barrel upward and extends into the barrel. An ejection plate is fixedly mounted on the active end of the piston rod of the ejection oil cylinder.

[0020] The horizontal oil cylinder, the second drive motor and the three-jaw chuck are located on the same horizontal straight line.

[0021] Two clamping oil cylinders are fixedly arranged on the bottom surface of the mounting plate, and the clamping heads of the two clamping oil cylinders are both located just above the barrel.

[0022] The welding and rolling mechanism comprises a hydraulic slide fixed on the workbench, a frame fixed on the top surface of the moving platform of the hydraulic slide, and a feed oil cylinder fixed in the frame, the piston rod of the feed oil cylinder passes through the top edge of the frame upward, and a bearing plate is fixed on the extended end, a plurality of sleeves are fixed in the bearing plate at intervals along the height direction thereof, each sleeve is provided with a step hole, and the aperture of the large hole of the step hole is equal to the outer diameter of the small-sized oil pipe nipple;

[0023] A base located on the right side of the supporting plate is fixed on the top surface of the frame, a press is fixed on the right end surface of the base, a piston rod of the press passes through the base to the left, and a press head is fixed on the extended end, the press head is opposite to the first step hole on the left and right.

[0024] The vertical spacing between every two adjacent sleeves is equal.

[0025] The welding device also includes a controller, which is electrically connected to the first drive motor, the second drive motor, the third drive motor, the roller motor, the vertical cylinder, the horizontal cylinder, the ejection cylinder, the clamping cylinder, the hydraulic slide, the feed cylinder, and the pressurizer via a signal line.

[0026] A high-efficiency and high-quality welding method for welding double oil pipe short sections, comprising the following steps:

[0027] S1. Pre-installation of large-size oil pipe short sections: Workers take out multiple large-size oil pipe short sections and put them into the barrel from the top port of the barrel of the ejection mechanism. At this time, the bottom layer of large-size oil pipe short sections is just supported on the top surface of the ejection plate, and the top layer of large-size oil pipe short sections is just flush with the top surface of the barrel, thereby realizing the pre-installation of multiple large-size oil pipe short sections;

[0028] S2. Pre-installation of small-sized oil pipe nipples: The worker takes out a plurality of small-sized oil pipe nipples, and inserts a small-sized oil pipe nipple into the step holes of each sleeve of the insertion mechanism from left to right, and ensures that the right end surface of the small-sized oil pipe nipple abuts against the step surface of the step hole, thereby realizing the pre-installation of a plurality of small-sized oil pipe nipples;

[0029] S3. Grab the top large-size tubing nipple in the barrel. The specific operation steps are as follows:

[0030] S31, the piston rod of the vertical oil cylinder of the control grabbing mechanism is extended downward, the piston rod drives the mounting plate to move downward, the mounting plate drives the two clamping oil cylinders to move downward synchronously, the clamping oil cylinder drives the chuck to move toward the barrel, when the piston rod of the vertical oil cylinder is fully extended, the chuck is just close to the top port of the barrel;

[0031] S32, the piston rod of the ejection oil cylinder of the control ejection mechanism is extended upward, the piston rod drives the ejection plate to move upward, and the ejection plate drives all the large-size oil pipe short sections stacked in the barrel to move upward synchronously. When the piston rod of the ejection oil cylinder is extended to the set distance, the controller controls the ejection oil cylinder to close. At this time, the large-size oil pipe short section on the top layer is just pushed into the chuck of the clamping oil cylinder;

[0032] S33, control the clamping oil cylinder to start, the clamping oil cylinder drives the clamp to close, and the clamp clamps and fixes the top large-size oil pipe short section;

[0033] S34, control the piston rod of the vertical oil cylinder to retract upward, the piston rod drives the mounting plate to move upward, the mounting plate drives the clamping oil cylinder and the chuck to move upward synchronously, the chuck drives the clamped large-size oil pipe short section to move upward synchronously, so that the clamped large-size oil pipe short section is separated from the barrel, thereby realizing the grasping of the large-size oil pipe short section;

[0034] S4. Insert the small-sized tubing nipple into the large-sized tubing nipple. The specific operation steps are as follows:

[0035] S41, controlling the first drive motor of the grabbing mechanism to start, the first drive motor drives the rotating plate to rotate, the rotating plate drives the vertical cylinder, the clamping cylinder and the large-size oil pipe short section to rotate synchronously, and when the large-size oil pipe short section rotates 180°, the controller controls the first drive motor to turn off;

[0036] S42, control the piston rod of the vertical oil cylinder to extend upward, the piston rod drives the mounting plate to move upward, the mounting plate drives the clamping oil cylinder, the chuck and the large-size oil pipe short section to move upward synchronously, when the piston rod of the vertical oil cylinder is fully extended, the clamped large-size oil pipe short section is opposite to the three-jaw chuck on the left and right;

[0037] S43, the piston rod of the feed cylinder of the control insertion mechanism is extended upward, the piston rod drives the bearing plate to move upward, and the bearing plate drives each small-sized oil pipe short section thereon to move upward synchronously. When the piston rod of the feed cylinder is extended upward to a set distance, the controller controls the feed cylinder to be closed. At this time, the first small-sized oil pipe short section is just opposite to the large-sized oil pipe short section on the left and right;

[0038] S44, controlling the movable table of the hydraulic slide of the insertion mechanism to move to the left, the movable table drives the frame to move to the left, the frame drives the feed cylinder, the bearing plate, and the press to move to the left synchronously, and the bearing plate drives the sleeve and the small-size oil pipe short section to move to the left synchronously;

[0039] S45, when the moving platform moves to the left limit position of the hydraulic slide, the controller controls the hydraulic slide to close, at which time, the left end of the first small-size oil pipe nipple is just close to the right port of the large-size oil pipe nipple;

[0040] S46, the piston rod of the pressurizing machine controlling the insertion mechanism extends to the left, and the piston rod drives the pressurizing head to move to the left. The pressurizing head first enters the step hole of the first sleeve, and then the pressurizing head gradually pushes the left end of the small-sized oil pipe short section into the right port of the large-sized oil pipe short section. When the piston rod of the pressurizing machine is fully extended, the left end of the small-sized oil pipe short section is finally inserted into the right port of the large-sized oil pipe short section. At this time, the large-sized oil pipe short section and the small-sized oil pipe short section form an interference fit.

[0041] S5. Weld the large-size tubing nipple and the small-size tubing nipple together. The specific steps are as follows:

[0042] S51, controlling the piston rod of the horizontal oil cylinder of the grasping mechanism to extend to the right, the piston rod drives the second drive motor and the three-jaw chuck to move to the right synchronously, and the three-jaw chuck moves toward the direction of the large-size oil pipe short section. When the piston rod of the horizontal oil cylinder is fully extended, the three-jaw chuck just covers the left end of the large-size oil pipe short section; then controlling the three-jaw chuck to start, and the claws of the three-jaw chuck clamp and fix the left end of the large-size oil pipe short section;

[0043] S52, the clamping oil cylinder is controlled to be closed, and the clamping oil cylinder drives the chuck to open, so that the chuck no longer clamps the large-size oil pipe short section, and then the piston rod of the vertical oil cylinder is controlled to retract downward, and the piston rod drives the clamping oil cylinder and the chuck to move downward, so that the chuck moves to the bottom of the large-size oil pipe short section;

[0044] S53, controlling the second drive motor of the grabbing mechanism to start, the second drive motor drives the three-jaw chuck to rotate, the three-jaw chuck drives the large-size tubing nipple to rotate synchronously around its own axis, and the large-size tubing nipple also drives the small-size tubing nipple to rotate synchronously;

[0045] S54, the worker controls the laser welding machine connected to the welding head to start, and the laser beam emitted downward by the welding head acts on the right end of the large-size oil pipe short section. When the large-size oil pipe short section rotates one circle, the laser beam forms a circle of annular weld scars on the outer surface of the right end of the large-size oil pipe short section, thereby welding the large-size oil pipe short section and the small-size oil pipe short section together;

[0046] S55, after welding, the laser welding machine is controlled to be turned off, and then the third driving motor of the welding and rolling mechanism is controlled to be started, the third driving motor drives the turntable to rotate, and the turntable drives the welding head, the rolling cylinder, the U-shaped frame, the rolling motor and the rolling wheel to rotate synchronously. After the turntable rotates 180°, the controller controls the third driving motor to be turned off, and at this time, the rolling wheel is just above the right end of the large-size oil pipe short section;

[0047] S56, control the roller pressing motor to start, the roller pressing motor drives the main shaft to rotate around its own axis, and the main shaft drives the roller pressing wheel to rotate synchronously; then control the piston rod of the roller pressing oil cylinder to extend downward, the piston rod drives the U-shaped frame, the roller pressing motor and the roller pressing wheel to move downward synchronously, and the roller pressing wheel that performs rotating motion gradually presses the rotating large-sized oil pipe short section from top to bottom. When the roller pressing wheel moves downward to a certain distance, the outer wall material of the large-sized oil pipe short section is squeezed into the outer wall material of the small-sized oil pipe short section to form an annular protrusion, thereby finally producing the first product B;

[0048] S6. The specific steps of taking out product B are as follows:

[0049] S61, control the piston rod of the roller pressing cylinder to retract upward, and the piston rod drives the U-shaped frame, the roller pressing motor and the roller pressing wheel to move upward synchronously, and the roller pressing wheel is separated from the product B;

[0050] S62, control the movable platform of the hydraulic slide table to move rightward, the movable platform drives the frame to move leftward, the frame drives the feed cylinder, the bearing plate, and the press to move rightward synchronously, and the bearing plate drives other small-sized oil pipe short sections thereon to move rightward;

[0051] S63, the worker holds product B, and then controls the three-jaw chuck to close, the jaws of the three-jaw chuck are separated from the large-size tubing nipple of product B, and then the worker takes product B away;

[0052] S7. The worker repeats the operations of steps S3 to S6 to continuously weld the large-sized tubing nipples in the barrel with the small-sized tubing nipples on the carrier plate, thereby continuously producing a plurality of required products B.

[0053] The present invention has the following advantages: greatly improving the welding efficiency of a large-sized oil pipe pup joint and a small-sized oil pipe pup joint, and greatly improving the welding quality of a large-sized oil pipe pup joint and a small-sized oil pipe pup joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a schematic diagram of the structure of a large-size tubing nipple;

[0055] Figure 2 It is a structural schematic diagram of a small-sized tubing nipple;

[0056] Figure 3 It is a structural diagram of product A;

[0057] Figure 4 for Figure 3 The main cross-sectional diagram of

[0058] Figure 5 A schematic diagram of fixing the left end of a large-size oil pipe nipple to the three-jaw chuck of a machine tool;

[0059] Figure 6 A schematic diagram of aligning the welding head of a laser welding machine with the right end of a large-size tubing nipple;

[0060] Figure 7 It is a structural schematic diagram of the present invention;

[0061] Figure 8 for Figure 7 The main cross-sectional diagram of

[0062] Fig. 9 It is a schematic diagram of the connection between the grabbing mechanism and the ejecting mechanism;

[0063] Fig.10 for Fig. 9 AA cross-section diagram of ;

[0064] Fig.11 It is a structural schematic diagram of the welding and rolling mechanism;

[0065] Fig.12 for Fig.11 A schematic diagram of the connection between the U-shaped frame, the main shaft and the roller pressing wheel;

[0066] Fig.13 It is a structural schematic diagram of the plug-in mechanism;

[0067] Fig.14 It is a schematic diagram of the connection between the bearing plate and the sleeve;

[0068] Fig.15 for Fig.14 The main cross-sectional diagram of

[0069] Fig.16 Schematic diagram for pre-installing multiple large-size tubing nipples;

[0070] Fig.17 for Fig.16 BB cross-section diagram;

[0071] Fig.18 A schematic diagram for pre-installing multiple small-sized tubing nipples;

[0072] Fig.19 A schematic diagram of the clamping head of the clamping cylinder approaching the top port of the barrel;

[0073] Fig. 20 It is a schematic diagram of the topmost large-size oil pipe short joint being pushed into the chuck of the clamping cylinder;

[0074] Fig.21 for Fig. 20 Schematic diagram of CC cross section;

[0075] Fig. 22A schematic diagram of a clamping cylinder clamping the topmost large-size oil pipe nipple;

[0076] Fig.23 It is a schematic diagram of the separation of a large-size tubing nipple from a barrel;

[0077] Fig.24 It is a schematic diagram of a large-size tubing nipple and a three-jaw chuck facing each other on the left and right;

[0078] Fig.25 It is a schematic diagram of the left end of the first small-sized tubing nipple approaching the right port of the large-sized tubing nipple;

[0079] Fig.26 A schematic diagram of inserting the left end of a small-sized tubing nipple into the right port of a large-sized tubing nipple;

[0080] Fig. 27 The diagram is a diagram showing that the jaws of a three-jaw chuck clamp and fix the left end of a large-sized tubing nipple;

[0081] Fig.28 A schematic diagram of forming a circle of annular weld scars on the outer surface of the right end of a large-size oil pipe nipple;

[0082] Fig.29 for Fig.28 A partial enlarged view of the D part;

[0083] Fig.30 It is a schematic diagram showing that the roller is located directly above the right end of the large-size tubing nipple;

[0084] Fig.31 It is a schematic diagram of the roller rolling the outer wall of a large-sized oil pipe short section from top to bottom;

[0085] Fig.32 A schematic diagram for taking away product B;

[0086] Fig.33 It is a schematic diagram of the structure of the produced product B;

[0087] In the figure:

[0088] 1-large size tubing nipple, 2-small size tubing nipple, 3-welding joint, 4-annular weld scar;

[0089] 5-working table, 6-grasping mechanism, 7-ejection mechanism, 8-insertion mechanism, 9-welding and rolling mechanism;

[0090] 10-vertical plate, 11-first drive motor, 12-horizontal cylinder, 13-rotating plate, 14-vertical cylinder, 15-clamping cylinder, 16-chuck, 17-second drive motor, 18-three-jaw chuck;

[0091] 19-connecting frame, 20-third driving motor, 21-turntable, 22-rolling cylinder, 23-U-shaped frame, 24-main shaft, 25-rolling wheel;

[0092] 26-barrel, 27-ejection cylinder, 28-ejection plate; 29-hydraulic slide, 30-moving table, 31-feed cylinder, 32-bearing plate, 33-sleeve, 34-step hole, 35-pressing machine, 36-pressing head, 37-annular protrusion. DETAILED DESCRIPTION

[0093] The present invention is further described below in conjunction with the accompanying drawings, and the protection scope of the present invention is not limited to the following: Figure 7 to Figure 15 As shown, a welding device for welding double oil pipe pup joints with high efficiency and high quality comprises a workbench 5, on which are arranged, from left to right, a grasping mechanism 6 for grasping a large-sized oil pipe pup joint 1, an ejecting mechanism 7 for ejecting the large-sized oil pipe pup joint 1, and an inserting mechanism 8 for tooling and pushing a small-sized oil pipe pup joint 2, and a welding and rolling mechanism 9 is arranged on the grasping mechanism 6; a plurality of support frames are fixedly arranged on the bottom surface of the workbench 5, and the support frames are supported on the ground.

[0094] The grabbing mechanism 6 includes a vertical plate 10 fixedly mounted on the workbench 5, a first drive motor 11 fixedly mounted on the left end surface of the vertical plate 10, and a horizontal cylinder 12 fixedly mounted on the top surface of the vertical plate 10. The output shaft of the first drive motor 11 penetrates the vertical plate 10 to the right, and a rotating plate 13 is fixedly mounted on the extended end. A vertical cylinder 14 is fixedly mounted on the right end surface of the rotating plate 13. The piston rod of the vertical cylinder 14 extends downward, and a mounting plate is fixedly mounted on the extended end. A plurality of clamping cylinders 15 are fixedly mounted on the bottom surface of the mounting plate, and the chuck 16 of the clamping cylinder 15 is arranged downward. The piston rod of the horizontal cylinder 12 extends to the right, and a second drive motor 17 is fixedly mounted on the extended end. A three-jaw chuck 18 with an opening facing right is connected to the output shaft of the second drive motor 17. The horizontal cylinder 12, the second drive motor 17 and the three-jaw chuck 18 are located on the same horizontal straight line. Two clamping cylinders 15 are fixedly disposed on the bottom surface of the mounting plate, and the clamping heads 16 of the two clamping cylinders 15 are both located directly above the barrel 26 .

[0095] The welding and rolling mechanism 9 includes a connecting frame 19 fixedly arranged on the top surface of the vertical plate 10, the connecting frame 19 extends to the right on the right side of the vertical plate 10, and a third drive motor 20 is fixedly arranged on the top surface of the extended end, the output shaft of the third drive motor 20 passes through the connecting frame 19 downward, and a turntable 21 is fixedly arranged on the extended end, the left end of the turntable 21 is fixedly connected to the welding head 3 of the laser welding machine, a rolling cylinder 22 is fixedly arranged on the top surface of the right end of the turntable 21, the piston rod of the rolling cylinder 22 passes through the turntable 21 downward, and a U-shaped frame 23 is fixedly connected to the extended end, a main shaft 24 is rotatably installed in the U-shaped frame 23, two rolling wheels 25 arranged at intervals are fixedly arranged on the main shaft 24, a rolling motor is fixedly arranged on the left end surface of the U-shaped frame 23, and the output shaft of the rolling motor is connected to the main shaft 24.

[0096] The ejection mechanism 7 includes a barrel 26 fixedly mounted on the workbench 5 and an ejection cylinder 27 fixedly mounted on the bottom surface of the workbench 5. The inner cavity of the barrel 26 matches the outer contour of the large-size oil pipe nipple 1. The piston rod of the ejection cylinder 27 sequentially penetrates the workbench 5 and the bottom wall of the barrel 26 upward and extends into the barrel 26. An ejection plate 28 is fixedly mounted on the active end of the piston rod of the ejection cylinder 27.

[0097] The welding and rolling mechanism 9 includes a hydraulic slide 29 fixed on the workbench 5, a frame fixed on the top surface of the movable platform 30 of the hydraulic slide 29, and a feed cylinder 31 fixed in the frame. The piston rod of the feed cylinder 31 passes through the top edge of the frame upward, and a bearing plate 32 is fixed on the extended end. A plurality of sleeves 33 are fixed in the bearing plate 32 along its height direction. The vertical spacing between each two adjacent sleeves 33 is equal. A step hole 34 is opened in each sleeve 33. The aperture of the large hole of the step hole 34 is equal to the outer diameter of the small-size oil pipe short section 2. A base located on the right side of the bearing plate 32 is fixed on the top surface of the frame, and a pressurizing machine 35 is fixed on the right end surface of the base. The piston rod of the pressurizing machine 35 passes through the base to the left, and a pressurizing head 36 is fixed on the extended end. The pressurizing head 36 is opposite to the first step hole 34 on the left and right.

[0098] The welding device also includes a controller, which is electrically connected to the first drive motor 11, the second drive motor 17, the third drive motor 20, the roller motor, the vertical cylinder 14, the horizontal cylinder 12, the ejection cylinder 27, the clamping cylinder 15, the hydraulic slide 29, the feed cylinder 31, and the press 35 via a signal line. The worker can start or shut down the first drive motor 11, the second drive motor 17, the third drive motor 20, and the roller motor, and at the same time control the extension or retraction of the piston rods of the horizontal cylinder 12, the ejection cylinder 27, the feed cylinder 31, and the press 35, which facilitates the worker's operation and has the characteristics of a high degree of automation.

[0099] A high-efficiency and high-quality welding method for welding double oil pipe short sections, comprising the following steps:

[0100] S1. Pre-installation of large-size tubing nipple 1: Workers take out several Figure 1 The large-size tubing nipple 1 shown in the figure is put into the barrel 26 from the top port of the barrel 26 of the ejection mechanism 7. At this time, the bottom layer of the large-size tubing nipple 1 is just supported on the top surface of the ejection plate 28, and the top layer of the large-size tubing nipple 1 is just flush with the top surface of the barrel 26, thereby realizing the pre-installation of multiple large-size tubing nipple 1. Figure 16-17 As shown;

[0101] S2. Pre-installation of small-size tubing nipple 2: Workers take out several Figure 2 As shown in the small-sized tubing nipple 2, the worker inserts a small-sized tubing nipple 2 from left to right into the step hole 34 of each sleeve 33 of the insertion mechanism 8, and ensures that the right end face of the small-sized tubing nipple 2 abuts against the step surface of the step hole 34, thereby realizing the pre-installation of multiple small-sized tubing nipple 2. Fig.18 As shown;

[0102] S3, grab the top layer of the large-size tubing nipple 1 in the barrel 26, and the specific operation steps are as follows:

[0103] S31, control the piston rod of the vertical oil cylinder 14 of the grabbing mechanism 6 to extend downward, the piston rod drives the mounting plate to move downward, the mounting plate drives the two clamping oil cylinders 15 to move downward synchronously, the clamping oil cylinders 15 drive the chuck 16 to move toward the barrel 26, when the piston rod of the vertical oil cylinder 14 is fully extended, the chuck 16 is just close to the top end of the barrel 26, as shown in FIG. Fig.19 As shown;

[0104] S32, the piston rod of the ejection cylinder 27 of the ejection mechanism 7 is controlled to extend upward, and the piston rod drives the ejection plate 28 to move upward, and the ejection plate 28 drives all the large-size oil pipe short sections 1 stacked in the barrel 26 to move upward synchronously. When the piston rod of the ejection cylinder 27 is extended to the set distance, the controller controls the ejection cylinder 27 to close. At this time, the top large-size oil pipe short section 1 is just pushed into the chuck 16 of the clamping cylinder 15, as shown in FIG. Figure 20~Figure 21 As shown;

[0105] S33, control the clamping oil cylinder 15 to start, the clamping oil cylinder 15 drives the clamp 16 to close, and the clamp 16 clamps and fixes the top large-size oil pipe short section 1, such as Fig. 22 As shown;

[0106] S34, control the piston rod of the vertical oil cylinder 14 to retract upward, the piston rod drives the mounting plate to move upward, the mounting plate drives the clamping oil cylinder 15 and the chuck 16 to move upward synchronously, the chuck 16 drives the clamped large-size oil pipe short section 1 to move upward synchronously, so that the clamped large-size oil pipe short section 1 is separated from the barrel 26, as shown in FIG. Fig.23 As shown, the large-sized tubing nipple 1 is grasped;

[0107] S4. Insert the small-size tubing nipple 2 into the large-size tubing nipple 1. The specific operation steps are as follows:

[0108] S41, control the first drive motor 11 of the grabbing mechanism 6 to start, the first drive motor 11 drives the rotating plate 13 to rotate, the rotating plate 13 drives the vertical cylinder 14, the clamping cylinder 15 and the large-size oil pipe short section 1 to rotate synchronously, and when the large-size oil pipe short section 1 rotates 180°, the controller controls the first drive motor 11 to turn off;

[0109] S42, control the piston rod of the vertical oil cylinder 14 to extend upward, the piston rod drives the mounting plate to move upward, the mounting plate drives the clamping oil cylinder 15, the chuck 16 and the large-size oil pipe short section 1 to move upward synchronously, when the piston rod of the vertical oil cylinder 14 is fully extended, the clamped large-size oil pipe short section 1 is opposite to the three-jaw chuck 18, as shown in FIG. Fig.24 As shown;

[0110] S43, the piston rod of the feed cylinder 31 of the insertion mechanism 8 is controlled to extend upward, and the piston rod drives the bearing plate 32 to move upward, and the bearing plate 32 drives each small-sized oil pipe short section 2 thereon to move upward synchronously. When the piston rod of the feed cylinder 31 extends upward to a set distance, the controller controls the feed cylinder 31 to close. At this time, the first small-sized oil pipe short section 2 is just opposite to the large-sized oil pipe short section 1 on the left and right.

[0111] S44, control the moving platform 30 of the hydraulic slide 29 of the insertion mechanism 8 to move leftward, the moving platform 30 drives the frame to move leftward, the frame drives the feed cylinder 31, the bearing plate 32, and the pressurizing machine 35 to move leftward synchronously, and the bearing plate 32 drives the sleeve 33 and the small-size oil pipe nipple 2 to move leftward synchronously;

[0112] S45, when the moving platform 30 moves to the left limit position of the hydraulic slide 29, the controller controls the hydraulic slide 29 to close. At this time, the left end of the first small-sized tubing nipple 2 is just close to the right end of the large-sized tubing nipple 1. Fig.25 As shown;

[0113] S46, the piston rod of the pressurizing machine 35 of the control insertion mechanism 8 is extended to the left, and the piston rod drives the pressurizing head 36 to move to the left. The pressurizing head 36 first enters the step hole 34 of the first sleeve 33, and then the pressurizing head 36 gradually pushes the left end of the small-sized tubing nipple 2 into the right port of the large-sized tubing nipple 1. When the piston rod of the pressurizing machine 35 is fully extended, the left end of the small-sized tubing nipple 2 is finally inserted into the right port of the large-sized tubing nipple 1. Fig.26 As shown, at this time, the large-size tubing nipple 1 and the small-size tubing nipple 2 form an interference fit;

[0114] S5. Weld the large-size tubing nipple 1 and the small-size tubing nipple 2 together. The specific operation steps are as follows:

[0115] S51, control the piston rod of the horizontal oil cylinder 12 of the grasping mechanism 6 to extend to the right, and the piston rod drives the second drive motor 17 and the three-jaw chuck 18 to move to the right synchronously, and the three-jaw chuck 18 moves toward the direction of the large-size oil pipe short section 1. When the piston rod of the horizontal oil cylinder 12 is fully extended, the three-jaw chuck 18 just fits on the left end of the large-size oil pipe short section 1; then control the three-jaw chuck 18 to start, and the claws of the three-jaw chuck 18 clamp and fix the left end of the large-size oil pipe short section 1, as shown in FIG. Fig. 27 As shown;

[0116] S52, control the clamping oil cylinder 15 to close, the clamping oil cylinder 15 drives the chuck 16 to open, the chuck 16 no longer clamps the large-size tubing nipple 1, and then control the piston rod of the vertical oil cylinder 14 to retract downward, the piston rod drives the clamping oil cylinder 15 and the chuck 16 to move downward, so that the chuck 16 moves to the bottom of the large-size tubing nipple 1;

[0117] S53, control the second drive motor 17 of the grabbing mechanism 6 to start, the second drive motor 17 drives the three-jaw chuck 18 to rotate, the three-jaw chuck 18 drives the large-size tubing nipple 1 to rotate synchronously around its own axis, and the large-size tubing nipple 1 also drives the small-size tubing nipple 2 to rotate synchronously, and the rotation direction is as follows: Figure 28-29 As indicated by the arrow;

[0118] S54, the worker controls the laser welding machine connected to the welding head 3 to start, and the laser beam emitted downward by the welding head 3 acts on the right end of the large-size oil pipe short section 1. When the large-size oil pipe short section 1 rotates one circle, the laser beam forms a circle of annular weld scar 4 on the outer surface of the right end of the large-size oil pipe short section 1, as shown in FIG. Figure 28-29 As shown, the large-size tubing nipple 1 and the small-size tubing nipple 2 are welded together;

[0119] S55, after welding, the laser welding machine is controlled to be turned off, and then the third driving motor 20 of the welding and rolling mechanism 9 is controlled to start, the third driving motor 20 drives the turntable 21 to rotate, and the turntable 21 drives the welding head 3, the rolling cylinder 22, the U-shaped frame 23, the rolling motor and the rolling wheel 25 to rotate synchronously. After the turntable 21 rotates 180°, the controller controls the third driving motor 20 to be turned off. At this time, the rolling wheel 25 is just above the right end of the large-size tubing short section 1. Fig.30 As shown;

[0120] S56, control the rolling motor to start, the rolling motor drives the main shaft 24 to rotate around its own axis, and the main shaft 24 drives the rolling wheel 25 to rotate synchronously; then control the piston rod of the rolling cylinder 22 to extend downward, the piston rod drives the U-shaped frame 23, the rolling motor and the rolling wheel 25 to move downward synchronously, and the rotating rolling wheel 25 gradually rolls the rotating large-size tubing short section 1 from top to bottom. When the rolling wheel 25 moves downward to a certain distance, the outer wall material of the large-size tubing short section 1 is squeezed into the outer wall material of the small-size tubing short section 2, such as Fig.31 As shown, an annular protrusion 37 is formed, thereby finally producing a first product B, the structure of which is as follows Fig.33 As shown;

[0121] Among them, it can be seen from step S5 that the outer wall material of the large-sized tubing nipple 1 in product B is squeezed into the small-sized tubing nipple 2 by the roller 25, forming an annular protrusion 37, that is, the annular protrusion 37 hangs the small-sized tubing nipple 2, thereby effectively preventing the small-sized tubing nipple 2 from coming off the large-sized tubing nipple 1 when the small-sized tubing nipple 2 is subjected to external axial force. Therefore, compared with product A produced by the welding method used in the workshop, the welding device of this invention greatly improves the welding quality of the large-sized tubing nipple 1 and the small-sized tubing nipple 2.

[0122] S6. The specific steps of taking out product B are as follows:

[0123] S61, the piston rod of the roller pressing oil cylinder 22 is controlled to retract upward, and the piston rod drives the U-shaped frame 23, the roller pressing motor and the roller pressing wheel 25 to move upward synchronously, and the roller pressing wheel 25 is separated from the product B;

[0124] S62, control the moving platform 30 of the hydraulic slide 29 to move rightward, the moving platform 30 drives the frame to move leftward, the frame drives the feed cylinder 31, the bearing plate 32, and the press 35 to move rightward synchronously, and the bearing plate 32 drives other small-sized oil pipe short sections 2 thereon to move rightward;

[0125] S63, the worker holds the product B, and then controls the three-jaw chuck 18 to close, the claws of the three-jaw chuck 18 are separated from the large-size tubing nipple 1 of the product B, and then the worker takes the product B away, and the direction of taking away is as follows: Fig.32 As indicated by the arrow;

[0126] S7. The worker repeats the operations of steps S3 to S6 to continuously weld the large-size tubing nipple 1 in the barrel 26 and the small-size tubing nipple 2 on the carrier plate 32, thereby continuously producing a plurality of required products B.

[0127] Among them, it can be seen from steps S3 to S5 that the present welding device can realize the insertion of the large-size tubing nipple 1 and the small-size tubing nipple 2, as well as the welding of the large-size tubing nipple 1 and the small-size tubing nipple 2, through the linkage cooperation of the grabbing mechanism 6, the ejecting mechanism 7, the welding and rolling mechanism 9, and the insertion mechanism 8, thereby obtaining the product B. It can be seen that the present welding device is better than the Figure 5~Figure 6 The welding method shown does not require manual work to fix the left end of the large-size tubing nipple 1 on the three-jaw chuck of the machine tool, nor does it require manual work to align the welding head 3 of the laser welding machine with the right end of the large-size tubing nipple 1. Instead, automatic welding is achieved, thereby greatly shortening the welding time of the large-size tubing nipple 1 and the small-size tubing nipple 2, thereby greatly improving the welding efficiency of the large-size tubing nipple 1 and the small-size tubing nipple 2.

[0128] In addition, the present welding device can automatically weld the large-size tubing nipple 1 in the barrel 26 with the small-size tubing nipple 2 on the carrier plate 32 through the linkage of the grabbing mechanism 6, the ejecting mechanism 7, the welding and rolling mechanism 9, and the inserting mechanism 8, thereby continuously producing a plurality of required products B. Figure 5~Figure 6 The welding method shown greatly shortens the welding time of the large-size tubing nipple 1 and the small-size tubing nipple 2, and further improves the welding efficiency of the large-size tubing nipple 1 and the small-size tubing nipple 2.

Claims

1. A method for welding a double oil pipe short section with high efficiency and high quality, the method using a welding device for welding a double oil pipe short section with high efficiency and high quality, the welding device comprising a workbench (5), on which are arranged, from left to right, a grasping mechanism (6) for grasping a large-sized oil pipe short section (1), an ejecting mechanism (7) for ejecting the large-sized oil pipe short section (1), and an inserting mechanism (8) for tooling and pushing a small-sized oil pipe short section (2), and the grasping mechanism (6) is provided with a welding and rolling mechanism (9); The gripping mechanism (6) comprises a vertical plate (10) fixedly mounted on the workbench (5), a first drive motor (11) fixedly mounted on the left end surface of the vertical plate (10), and a horizontal oil cylinder (12) fixedly mounted on the top surface of the vertical plate (10); the output shaft of the first drive motor (11) penetrates the vertical plate (10) to the right, and a rotating plate (13) is fixedly mounted on the extended end; a vertical oil cylinder (14) is fixedly mounted on the right end surface of the rotating plate (13); the piston rod of the vertical oil cylinder (14) extends downwardly, and a mounting plate is fixedly mounted on the extended end; a plurality of clamping oil cylinders (15) are fixedly mounted on the bottom surface of the mounting plate; the clamping heads (16) of the clamping oil cylinders (15) are arranged downwardly; the piston rod of the horizontal oil cylinder (12) extends to the right, and a second drive motor (17) is fixedly mounted on the extended end; the output shaft of the second drive motor (17) is connected to a three-jaw chuck (18) with an opening facing rightward; The welding and rolling mechanism (9) comprises a connecting frame (19) fixedly arranged on the top surface of the vertical plate (10), the connecting frame (19) extending rightward to the right side of the vertical plate (10), and a third drive motor (20) is fixedly arranged on the top surface of the extension end, the output shaft of the third drive motor (20) passes through the connecting frame (19) downward, and a turntable (21) is fixedly arranged on the extension end, the left end of the turntable (21) is fixedly connected to the welding head (3) of the laser welding machine, a rolling cylinder (22) is fixedly arranged on the top surface of the right end of the turntable (21), the piston rod of the rolling cylinder (22) passes through the turntable (21) downward, and a U-shaped frame (23) is fixedly arranged on the extension end, a main shaft (24) is rotatably mounted in the U-shaped frame (23), two rolling wheels (25) arranged at intervals are fixedly arranged on the main shaft (24), a rolling motor is fixedly arranged on the left end surface of the U-shaped frame (23), and the output shaft of the rolling motor is connected to the main shaft (24); The ejection mechanism (7) comprises a barrel (26) fixedly mounted on the workbench (5) and an ejection oil cylinder (27) fixedly mounted on the bottom surface of the workbench (5); the inner cavity of the barrel (26) matches the outer contour of the large-size oil pipe nipple (1); the piston rod of the ejection oil cylinder (27) sequentially penetrates the workbench (5) and the bottom wall of the barrel (26) upwards and extends into the barrel (26); an ejection plate (28) is fixedly mounted on the active end of the piston rod of the ejection oil cylinder (27); The welding and rolling mechanism (9) comprises a hydraulic slide (29) fixedly mounted on a workbench (5), a frame fixedly mounted on the top surface of a movable platform (30) of the hydraulic slide (29), and a feed cylinder (31) fixedly mounted in the frame, wherein a piston rod of the feed cylinder (31) passes through the top edge of the frame upward, and a bearing plate (32) is fixedly mounted on the extended end, and a plurality of sleeves (33) are fixedly mounted in the bearing plate (32) at intervals along the height direction thereof, and each sleeve (33) is provided with a stepped hole (34), and the diameter of the large hole of the stepped hole (34) is equal to the outer diameter of the small-sized oil pipe nipple (2); A base is fixedly provided on the top surface of the frame and is located on the right side of the bearing plate (32). A pressurizing machine (35) is fixedly provided on the right end surface of the base. The piston rod of the pressurizing machine (35) passes through the base to the left, and a pressurizing head (36) is fixedly provided on the extended end. The pressurizing head (36) is opposite to the first step hole (34) on the left and right. The welding device further comprises a controller, which is electrically connected to a first drive motor (11), a second drive motor (17), a third drive motor (20), a roller motor, a vertical oil cylinder (14), a horizontal oil cylinder (12), an ejection oil cylinder (27), a clamping oil cylinder (15), a hydraulic slide (29), a feed oil cylinder (31), and a pressurizing machine (35) via a signal line, and is characterized in that: The method comprises the following steps: S1. Pre-installation of large-size oil pipe short sections (1): A worker takes out a plurality of large-size oil pipe short sections (1), and places the large-size oil pipe short sections (1) into the barrel (26) from the top port of the barrel (26) of the ejection mechanism (7). At this time, the large-size oil pipe short sections (1) at the bottom layer are just supported on the top surface of the ejection plate (28), and the large-size oil pipe short sections (1) at the top layer are just flush with the top surface of the barrel (26), thereby realizing the pre-installation of the plurality of large-size oil pipe short sections (1); S2. Pre-installation of small-sized oil pipe short sections (2): A worker takes out a plurality of small-sized oil pipe short sections (2), and inserts a small-sized oil pipe short section (2) from left to right into the step holes (34) of each sleeve (33) of the insertion mechanism (8), and ensures that the right end surface of the small-sized oil pipe short section (2) abuts against the step surface of the step hole (34), thereby achieving pre-installation of the plurality of small-sized oil pipe short sections (2); S3. Grab the topmost large-size tubing nipple (1) in the barrel (26). The specific operation steps are as follows: S31, controlling the piston rod of the vertical oil cylinder (14) of the grasping mechanism (6) to extend downward, the piston rod drives the mounting plate to move downward, the mounting plate drives the two clamping oil cylinders (15) to move downward synchronously, the clamping oil cylinders (15) drive the chuck (16) to move toward the barrel (26), and when the piston rod of the vertical oil cylinder (14) is fully extended, the chuck (16) is just close to the top end of the barrel (26); S32, controlling the piston rod of the ejection cylinder (27) of the ejection mechanism (7) to extend upward, the piston rod drives the ejection plate (28) to move upward, and the ejection plate (28) drives all the large-sized oil pipe short sections (1) stacked in the barrel (26) to move upward synchronously. When the piston rod of the ejection cylinder (27) extends to a set distance, the controller controls the ejection cylinder (27) to close. At this time, the top large-sized oil pipe short section (1) is just pushed into the chuck (16) of the clamping cylinder (15); S33, controlling the clamping oil cylinder (15) to start, the clamping oil cylinder (15) drives the clamping head (16) to close, and the clamping head (16) clamps and fixes the topmost large-size oil pipe short section (1); S34, controlling the piston rod of the vertical oil cylinder (14) to retract upward, the piston rod drives the mounting plate to move upward, the mounting plate drives the clamping oil cylinder (15) and the chuck (16) to move upward synchronously, the chuck (16) drives the clamped large-size oil pipe short section (1) to move upward synchronously, so that the clamped large-size oil pipe short section (1) is separated from the barrel (26), thereby achieving the grasping of the large-size oil pipe short section (1); S4. Insert the small-sized tubing nipple (2) into the large-sized tubing nipple (1). The specific operation steps are as follows: S41, controlling the first drive motor (11) of the grabbing mechanism (6) to start, the first drive motor (11) drives the rotating plate (13) to rotate, the rotating plate (13) drives the vertical cylinder (14), the clamping cylinder (15) and the large-size oil pipe short section (1) to rotate synchronously, and when the large-size oil pipe short section (1) rotates 180°, the controller controls the first drive motor (11) to turn off; S42, controlling the piston rod of the vertical oil cylinder (14) to extend upward, the piston rod drives the mounting plate to move upward, and the mounting plate drives the clamping oil cylinder (15), the chuck (16) and the large-size oil pipe short section (1) to move upward synchronously, and when the piston rod of the vertical oil cylinder (14) is fully extended, the clamped large-size oil pipe short section (1) is opposed to the three-jaw chuck (18) on the left and right; S43, controlling the piston rod of the feed cylinder (31) of the insertion mechanism (8) to extend upward, the piston rod drives the carrier plate (32) to move upward, and the carrier plate (32) drives each small-sized oil pipe short section (2) thereon to move upward synchronously. When the piston rod of the feed cylinder (31) extends upward to a set distance, the controller controls the feed cylinder (31) to close. At this time, the first small-sized oil pipe short section (2) is just opposite to the large-sized oil pipe short section (1) on the left and right. S44, controlling the movable platform (30) of the hydraulic slide (29) of the insertion mechanism (8) to move leftward, the movable platform (30) drives the frame to move leftward, the frame drives the feed cylinder (31), the bearing plate (32), and the pressurizing machine (35) to move leftward synchronously, and the bearing plate (32) drives the sleeve (33) and the small-size oil pipe short section (2) to move leftward synchronously; S45, when the moving platform (30) moves to the left limit position of the hydraulic slide (29), the controller controls the hydraulic slide (29) to close, at which time the left end of the first small-sized oil pipe short section (2) is just close to the right end of the large-sized oil pipe short section (1); S46, the piston rod of the pressurizing machine (35) of the control insertion mechanism (8) extends to the left, and the piston rod drives the pressurizing head (36) to move to the left. The pressurizing head (36) first enters the stepped hole (34) of the first sleeve (33), and then the pressurizing head (36) gradually pushes the left end of the small-sized oil pipe short section (2) into the right port of the large-sized oil pipe short section (1). When the piston rod of the pressurizing machine (35) is fully extended, the left end of the small-sized oil pipe short section (2) is finally inserted into the right port of the large-sized oil pipe short section (1). At this time, the large-sized oil pipe short section (1) and the small-sized oil pipe short section (2) form an interference fit; S5. Welding the large-size tubing nipple (1) and the small-size tubing nipple (2) together. The specific operation steps are as follows: S51, controlling the piston rod of the horizontal oil cylinder (12) of the grasping mechanism (6) to extend to the right, the piston rod drives the second drive motor (17) and the three-jaw chuck (18) to move to the right synchronously, and the three-jaw chuck (18) moves toward the direction of the large-size oil pipe short section (1). When the piston rod of the horizontal oil cylinder (12) is fully extended, the three-jaw chuck (18) just fits on the left end of the large-size oil pipe short section (1); then controlling the three-jaw chuck (18) to start, the claws of the three-jaw chuck (18) clamp and fix the left end of the large-size oil pipe short section (1); S52, controlling the clamping cylinder (15) to close, the clamping cylinder (15) drives the chuck (16) to open, the chuck (16) no longer clamps the large-size oil pipe short section (1), and then controlling the piston rod of the vertical cylinder (14) to retract downward, the piston rod drives the clamping cylinder (15) and the chuck (16) to move downward, so that the chuck (16) moves to the bottom of the large-size oil pipe short section (1); S53, controlling the second drive motor (17) of the grasping mechanism (6) to start, the second drive motor (17) drives the three-jaw chuck (18) to rotate, the three-jaw chuck (18) drives the large-size oil pipe short section (1) to rotate synchronously around its own axis, and the large-size oil pipe short section (1) also drives the small-size oil pipe short section (2) to rotate synchronously; S54, the worker controls the laser welding machine connected to the welding head (3) to start, and the laser beam emitted downward by the welding head (3) acts on the right end of the large-sized oil pipe short section (1). When the large-sized oil pipe short section (1) rotates one circle, the laser beam forms a circle of annular weld scars (4) on the outer surface of the right end of the large-sized oil pipe short section (1), thereby welding the large-sized oil pipe short section (1) and the small-sized oil pipe short section (2) together; S55, after welding, the laser welding machine is controlled to be turned off, and then the third drive motor (20) of the welding and rolling mechanism (9) is controlled to start, the third drive motor (20) drives the turntable (21) to rotate, and the turntable (21) drives the welding head (3), the rolling cylinder (22), the U-shaped frame (23), the rolling motor and the rolling wheel (25) to rotate synchronously. After the turntable (21) rotates 180 degrees, the controller controls the third drive motor (20) to be turned off, and at this time, the rolling wheel (25) is just above the right end of the large-size oil pipe short section (1); S56, controlling the rolling motor to start, the rolling motor drives the main shaft (24) to rotate around its own axis, and the main shaft (24) drives the rolling wheel (25) to rotate synchronously; then controlling the piston rod of the rolling cylinder (22) to extend downward, the piston rod drives the U-shaped frame (23), the rolling motor and the rolling wheel (25) to move downward synchronously, the rolling wheel (25) performing the rotating motion gradually rolls the rotating large-sized oil pipe short section (1) from top to bottom, when the rolling wheel (25) moves downward for a certain distance, the outer wall material of the large-sized oil pipe short section (1) is squeezed into the outer wall material of the small-sized oil pipe short section (2) to form an annular protrusion (37), thereby finally producing the first product B; S6. The specific steps of taking out product B are as follows: S61, the piston rod of the roller pressing oil cylinder (22) is controlled to retract upward, and the piston rod drives the U-shaped frame (23), the roller pressing motor and the roller pressing wheel (25) to move upward synchronously, and the roller pressing wheel (25) is separated from the product B; S62, controlling the movable platform (30) of the hydraulic slide (29) to move rightward, the movable platform (30) drives the frame to move leftward, the frame drives the feed cylinder (31), the bearing plate (32), and the press (35) to move rightward synchronously, and the bearing plate (32) drives other small-sized oil pipe short sections (2) thereon to move rightward; S63, the worker holds the product B, and then controls the three-jaw chuck (18) to close, the jaws of the three-jaw chuck (18) are separated from the large-size tubing nipple (1) of the product B, and then the worker takes the product B away; S7. The worker repeats the operations of steps S3 to S6 to continuously weld the large-sized oil pipe short section (1) in the barrel (26) and the small-sized oil pipe short section (2) on the supporting plate (32), thereby continuously producing a plurality of required products B.

2. The high-efficiency and high-quality welding method for welding double oil pipe short sections according to claim 1 is characterized in that: A plurality of support frames are fixedly arranged on the bottom surface of the workbench (5), and the support frames are supported on the ground.

3. The high-efficiency and high-quality welding method for welding double oil pipe short sections according to claim 2 is characterized in that: The horizontal oil cylinder (12), the second drive motor (17) and the three-jaw chuck (18) are located on the same horizontal straight line.

4. The high-efficiency and high-quality welding method for welding double oil pipe short sections according to claim 3 is characterized in that: Two clamping cylinders (15) are fixedly arranged on the bottom surface of the mounting plate, and the clamping heads (16) of the two clamping cylinders (15) are both located directly above the barrel (26).

5. The high-efficiency and high-quality welding method for welding double oil pipe short sections according to claim 4 is characterized in that: The vertical spacing between every two adjacent sleeves (33) is equal.

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