Special-shaped nut welding tool and control method thereof

Abstract

The invention provides a special-shaped nut welding tool and a control method thereof, and relates to the technical field of mechanical tools.The special-shaped nut welding tool comprises a positioner workbench, the bottom of the positioner workbench is driven by a positioner to rotate, eight positioning tables are annularly distributed at the positions, close to the edge, of the positioner workbench, and vertical air cylinders are arranged at the bottoms of the positioning tables; the lower end of the air cylinder is vertically embedded in a mounting groove of the positioner workbench through a bolt; a pipe fitting is vertically clamped at the upper end of the positioning table; according to all welding process parameters set by the argon arc welding robot, a weld pool is stably formed on the lap joint face of the outer side of the special-shaped nut and the pipe fitting, weld joints are continuous and complete and free of defects such as air holes, inclusions and pits, the requirement for welding airtightness is met, and experimental performance detection such as weld joint penetration depth can be passed.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical tooling, and in particular to a special-shaped nut welding tooling and a control method thereof. Background Art

[0002] Various modules in the National VI exhaust gas treatment assembly are equipped with sensor interfaces. These interfaces are mostly nuts, and welding processes are usually used to achieve permanent connection between them and pipe fittings, thereby ensuring the overall airtightness of the module. Tungsten inert gas arc welding (TIG welding) is a mature welding technology currently used. It is a non-melting electrode gas shielded arc welding that is very suitable for welding different types of stainless steel products. It uses the arc between the tungsten electrode and the workpiece to melt the metal to form a weld. During the welding process, the tungsten electrode does not melt and only acts as an electrode. At the same time, argon or helium is delivered into the nozzle of the welding torch for protection. Filler metal can also be added according to the needs of the weld design.

[0003] Currently, the forms of nut products are becoming more and more diverse, and even non-standard. It is very challenging to weld such sub-parts on stainless steel pipe fittings while providing excellent air tightness. Summary of the Invention

[0004] The invention relates to a special-shaped nut welding tool and a control method thereof, which can keep the positions of the special-shaped nut and a stainless steel pipe fixed, and completely seal the entire circle of the weld, thereby reducing defects caused by weld pores and pits and reducing the need for repair welding and rework.

[0005] The present invention provides a special-shaped nut welding tool and a control method thereof, specifically comprising: a positioner workbench, the bottom of the positioner workbench is driven to rotate by a positioner, eight positioning platforms are distributed in a ring near the edge of the positioner workbench, a vertical cylinder is provided at the bottom of the positioning platform, the lower end of the cylinder is vertically embedded in the mounting groove of the positioner workbench by a bolt; the upper end of the positioning platform is used to vertically clamp the pipe fitting; each of the positioning platforms is provided with an internal support device, and the internal support device is clamped by a cylinder; one side of the pipe fitting is a special-shaped nut to be welded, and an auxiliary positioning frame is provided between the positioning platform and the edge of the positioner workbench, a positioning pin is vertically slidably inserted in the auxiliary positioning frame, and the positioning pin is pushed up to determine the placement direction of the special-shaped nut on the pipe fitting; an independent cylinder switch is provided on the positioner workbench on each side of the cylinder.

[0006] Optionally, the inner support device includes six rails, and the rails are distributed in a ring shape at the bottom of the disc slot of the positioning platform, and the rails are distributed in a scattered manner along the diameter line of the positioning platform.

[0007] Optionally, the internal support device also includes a clamping block, a waist groove and a bundle spring. The number of the clamping blocks is also six. The clamping block is a fan-shaped structure. The bottom of the clamping block is provided with a sliding groove that is slidably engaged with the rail. The middle of the outer arc surface of the clamping block is provided with a waist groove. The bundle spring is installed between the waist grooves of the six clamping blocks. The bundle spring provides cohesive force for the clamping block. The upper end of the clamping block is higher than the upper end of the positioning platform, and the lower end of the inner cavity of the pipe is ringed on the outside of the six clamping blocks.

[0008] Optionally, the internal support device also includes an extrusion head and a threaded sleeve. The extrusion head is a truncated cone structure that is wide at the top and narrow at the bottom. The extrusion head is located between the six clamping blocks. The inner ends of the six clamping blocks are concave surface structures that fit the conical surface of the extrusion head. The lower end of the extrusion head is a threaded sleeve. The lower end of the threaded sleeve is threadedly connected to the upper end of the piston rod of the cylinder. The piston rod of the cylinder drives the extrusion head to move vertically, and the extrusion head moves downward, forcing the six clamping blocks to move outward. The six clamping blocks tighten the inner wall of the pipe fitting.

[0009] Optionally, the upper end of the locating pin is a Y-shaped head, and the width of the Y-shaped head is consistent with the diameter of the special-shaped nut.

[0010] A control method for a special-shaped nut welding tool comprises the following steps:

[0011] Step 1: Debug the TIG welding process parameters of the pipe fitting, welding current, argon gas flow and welding speed, and adjust the welding robot program, set the rotation angle and displacement speed of the robot welding gun, etc., to ensure that the thread weld of each special-shaped nut on the pipe fitting is complete and continuous.

[0012] Step 2: Place the non-interference end of the pipe fitting into the positioning tables of the tooling. Eight similar products can be placed at the same time. First, use the positioning pin to locate the same special-shaped nut to ensure that the direction and position to be welded are consistent.

[0013] Step 3: Open the eight cylinders on the positioning table so that the end of the pipe is clamped by the internal support device.

[0014] Step 4: Make an appointment for the welding procedure of the corresponding product, click the green start button of the robot workstation, and the entire workbench will rotate 45° sideways from the horizontal state so that the special-shaped nuts are vertically facing upwards and enter the welding posture.

[0015] Step 5: Fine-tune the working angle, welding speed, and welding process parameters of the welding robot to make the welding wire of the outer ring of the special-shaped nut melt evenly to form a stable molten pool, ensuring that the annular weld of each special-shaped nut is complete, continuous and dense.

[0016] The present invention provides a special-shaped nut welding tool and a control method thereof, which has the following beneficial effects:

[0017] 1. The present invention sets various welding process parameters through the argon arc welding robot, so that the outer side of the special-shaped nut and the overlapping surface of the pipe are stably formed into a molten pool, the weld is continuous and complete, without defects such as pores, inclusions, and depressions, meets the welding air tightness requirements, and can pass experimental performance tests such as weld penetration.

[0018] 2. The present invention adopts the angle of the re-rotating workbench for vertically clamping the pipe fittings, so that the welding posture of the nut is not affected by whether the shape is irregular or not, and the direction and position of the sub-parts are highly consistent. By adjusting a set of welding procedures, multiple parts of the same type can be repeatedly welded, which not only improves the welding efficiency and production capacity, but also ensures accurate welding positioning and improves other comprehensive performances such as weld width and excess height, further playing a role in suppressing welding deformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments are briefly introduced below.

[0020] The drawings described below only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0021] In the attached figure:

[0022] Figure 1 shows a first axial structural schematic diagram of the present invention;

[0023] Figure 2 The present invention shows Figure 1 A in the middle is a schematic diagram of the structure of the enlarged part;

[0024] Figure 3 It shows an axial structural schematic diagram of the pipe fitting and the positioning platform in a state of being separated;

[0025] Figure 4 It shows a schematic diagram of the axial structure of the present invention in a state without a pipe fitting;

[0026] Figure 5 It shows a schematic diagram of the axial structure of a single positioning platform of the present invention;

[0027] Figure 6 It shows a schematic diagram of the upper axis structure of the positioning platform of the present invention in a partially disassembled state;

[0028] Figure 7 It shows a schematic diagram of the axial structure of the positioning platform of the present invention in a partially disassembled state;

[0029] Figure 8 A partial axial structural schematic diagram of the clamping block of the present invention is shown.

[0030] Reference numerals

[0031] 1. Positioner workbench;

[0032] 2. Positioning platform; 21. Clamping rail; 22. Clamping block; 221. Slide groove; 222. Waist groove; 223. Beam spring;

[0033] 3. Cylinder; 31. Extrusion head; 311. Threaded sleeve;

[0034] 4. Pipe fittings; 41. Special-shaped nuts;

[0035] 5. Cylinder switch;

[0036] 6. Auxiliary positioning frame; 61. Positioning pin; 62. Y-shaped head. DETAILED DESCRIPTION

[0037] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of 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 described 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.

[0038] Example: Please refer to Figures 1 to 8 :

[0039] The present invention proposes a special-shaped nut welding tool and a control method thereof, comprising: a positioner workbench 1, the bottom of the positioner workbench 1 is driven to rotate by a positioner, and eight positioning platforms 2 are distributed in a ring near the edge of the positioner workbench 1, and a vertical cylinder 3 is provided at the bottom of the positioning platform 2, and the lower end of the cylinder 3 is vertically embedded in the mounting groove of the positioner workbench 1 by a bolt; the upper end of the positioning platform 2 vertically clamps the pipe fitting 4; each positioning platform 2 is provided with an internal support device, and the internal support device is clamped by the cylinder 3; one side of the pipe fitting 4 is a special-shaped nut 41 to be welded, and an auxiliary positioning frame 6 is provided between the positioning platform 2 and the edge of the positioner workbench 1, and a positioning pin 61 is vertically slidably inserted in the auxiliary positioning frame 6, and the positioning pin 61 is pushed up to determine the placement direction of the special-shaped nut 41 on the pipe fitting 4; an independent cylinder switch 5 is provided on the positioner workbench 1 on each side of the cylinder 3.

[0040] The inner support device includes six rails 21 , which are distributed in a ring shape at the bottom of the disc slot of the positioning platform 2 . The rails 21 are distributed in a scattered manner along the diameter line of the positioning platform 2 .

[0041] Among them, the internal support device also includes a clamping block 22, a waist groove 222 and a spring 223. There are also six clamping blocks 22. The clamping block 22 is a fan-shaped structure. The bottom of the clamping block 22 is provided with a sliding groove 221 that is slidably engaged with the rail 21. The middle of the outer end arc surface of the clamping block 22 is provided with a waist groove 222. The spring 223 is inserted between the waist grooves 222 of the six clamping blocks 22. The spring 223 provides cohesive force for the clamping block 22. The upper end of the clamping block 22 is higher than the upper end of the positioning platform 2, and the lower end of the inner cavity of the pipe 4 is ringed on the outside of the six clamping blocks 22.

[0042] Among them, the internal support device also includes an extrusion head 31 and a threaded sleeve 311. The extrusion head 31 is a truncated cone structure that is wide at the top and narrow at the bottom. The extrusion head 31 is located between the six clamping blocks 22. The inner ends of the six clamping blocks 22 are concave surface structures that fit the conical surface of the extrusion head 31. The lower end of the extrusion head 31 is a threaded sleeve 311. The lower end of the threaded sleeve 311 is threadedly connected to the upper end of the piston rod of the cylinder 3. The piston rod of the cylinder 3 drives the extrusion head 31 to move vertically. The extrusion head 31 moves downward, forcing the six clamping blocks 22 to move outward, and the six clamping blocks 22 tighten the inner wall of the pipe fitting 4.

[0043] The upper end of the positioning pin 61 is a Y-shaped head 62 , and the width of the Y-shaped head 62 is consistent with the diameter of the special-shaped nut 41 .

[0044] A control method for a special-shaped nut welding tool comprises the following steps:

[0045] Step 1: Debug the TIG welding process parameters of pipe fitting 4, welding current, argon gas flow and welding speed, and adjust the welding robot program, set the rotation angle and displacement speed of the robot welding gun, etc., so that the thread weld of each special-shaped nut 41 on pipe fitting 4 is complete and continuous.

[0046] Step 2: Place the non-interference end of the pipe fitting 4 into each positioning table 2 of the tooling. Eight similar products can be placed at the same time. First, use the positioning pin 61 to position the same special-shaped nut 41 to ensure that the direction and position to be welded are consistent.

[0047] Step 3: Open the eight cylinders 3 on the positioning platform 2 so that the ends of the pipes 4 are expanded and clamped by the inner support device.

[0048] Step 4: Make an appointment for the welding procedure of the corresponding product, click the green start button of the robot workstation, and the entire workbench will rotate 45° sideways from the horizontal state, so that the special-shaped nuts 41 are all vertically facing upwards to enter the welding posture.

[0049] Step 5: Fine-tune the working angle, welding speed, and welding process parameters of the welding robot to evenly melt the welding wire on the outer ring of the special-shaped nut 41 to form a stable molten pool, ensuring that the annular weld of each special-shaped nut 41 is complete, continuous, and dense.

[0050] The following further explains and illustrates the functions and effects of each structure in the above content so that those skilled in the art can better understand the technical solution:

[0051] The positioner workbench 1 serves as the basic platform for tooling, and its bottom drive mechanism realizes the overall rotation function; the eight positioning platforms 2 distributed in a ring maximize welding efficiency through spatial layout, realizing the simultaneous clamping of eight pipe fittings 4; the cylinder 3 at the bottom of each positioning platform 2 is vertically embedded in the mounting groove by bolts to ensure the stability of power transmission; the independent cylinder switch 5 design allows for separate control of the clamping action of each workstation, which is convenient for single-piece debugging or abnormal handling.

[0052] The internal support device achieves precise clamping through three-stage mechanical transmission. The six scattered rails 21 constitute a radial sliding reference, forming a directional guide rail with the slide groove 221 at the bottom of the clamping block 22; the waist groove 222 at the top of the fan-shaped clamping block 22 provides a constant cohesive force through the annular beam spring 223, so that the clamping block 22 remains in a retracted state in a natural state, which is convenient for the pipe fitting 4 to be inserted; the piston rod of the cylinder 3 pushes the threaded sleeve 311 to drive the truncated cone-shaped extrusion head 31 downward; the conical surface of the extrusion head 31 precisely fits the concave surface of the clamping block 22, converting the vertical thrust into a radial expansion force; when the six clamping blocks 22 expand outward synchronously, their outer arc surface forms a surface contact with the inner wall of the pipe fitting 4, and the elastic compensation function of the beam spring 223 can adapt to the pipe diameter tolerance of ±0.5mm to avoid deformation caused by local stress concentration.

[0053] The vertical slide rail of the auxiliary positioning frame 6 cooperates with the Y-head 62 positioning pin 61 to form double positioning. The fork width of the Y-head 62 accurately matches the diameter of the special-shaped nut 41. The circumferential angle of the nut is automatically corrected when pushed up. The vertical stroke of the positioning pin 61 covers pipes 4 of different specifications, ensuring that the welding end of the special-shaped nut 41 is always in the optimal reachable area of ​​the robot's welding gun.

[0054] The 45° lateral rotation function of the positioner workbench 1 allows all special-shaped nuts 41 to be converted from a horizontal clamping state to a vertical upward welding posture; this design eliminates the need for welding gun angle compensation, and cooperates with the welding robot program preset. The circularly distributed positioning table 2 ensures that the spacing between each weld point is constant, and the unified vertical posture makes the gravity flow direction of the molten pool consistent. The rotation angle of the positioner forms a spatial linkage with the robot welding path.

[0055] Through the mechanical optimization design of the internal support device (rail 21 / clamping block 22 / extrusion head 31), this tooling ensures the concentricity of the pipe fitting 4 is ≤0.1mm while avoiding surface indentations caused by traditional external clamps; the eight-station synchronous operation increases welding efficiency by 600%, and the directional function of the Y-head 62 positioning pin 61 reduces the product defective rate from the industry average of 5% to below 0.3%; the posture conversion of the positioner workbench 1 makes the welding penetration consistency reach 98%, meeting the weld flaw detection standards of high-end fields such as nuclear power pipe fittings 4.

[0056] Working principle:

[0057] When the operator places the non-interference end of the pipe 4 vertically into the positioning table 2, the lower end of the inner cavity of the pipe 4 is first inserted into the six clamping blocks 22 in a naturally retracted state; at this time, the bundle spring 223 applies a radially inward cohesive force to the clamping block 22 through the bundle waist groove 222, so that the outer arc surface of the clamping block 22 and the inner wall of the pipe 4 maintain a small gap (about 0.5-1mm), realizing rapid pre-positioning; then the positioning pin 61 in the auxiliary positioning frame 6 is pushed upward, and the Y-shaped head 62 at its top is precisely stuck in the outer edge of the special-shaped nut 41, and the circumferential angle of the nut is forced to be corrected by matching the fork width; in this process, the vertical sliding characteristics of the positioning pin 61 can adapt to pipes 4 of different heights, ensuring that the welding end face of the special-shaped nut 41 is always in the optimal working range of the robot welding gun.

[0058] After the cylinder switch 5 is triggered, the piston rod of the cylinder 3 pushes the extrusion head 31 downward through the threaded sleeve 311; the truncated cone structure of the extrusion head 31 converts the vertical mechanical force into a radial expansion force: its conical surface and the inner concave surface of the clamping block 22 produce a wedge-shaped extrusion effect, forcing the six clamping blocks 22 to slide synchronously outward along the scattered track of the rail 21; the beam spring 223 undergoes elastic deformation in this process, which not only ensures that the outer arc surface of the clamping block 22 forms a uniform surface contact with the inner wall of the pipe fitting 4, but also can adaptively compensate for the pipe diameter tolerance (±0.5mm); finally, a three-point mechanical balance is formed: ① the vertical thrust of the cylinder 3 ② the conical surface component of the extrusion head 31 ③ the elastic reset force of the beam spring 223, so that the pipe fitting 4 can obtain a coaxiality guarantee of ≤0.1mm and no surface indentation.

[0059] After completing the eight-station clamping, the positioner worktable 1 performs a 45° lateral rotation; this angle has been verified by fluid dynamics: when the special-shaped nut 41 is rotated from horizontal to vertical, the molten pool metal produces a directional flow due to gravity, which just offsets the arc blowing force during TIG welding; during the rotation process, the annular positioning platform 2 maintains a constant circumferential spacing between each pipe 4, so that the welding robot's welding gun movement path forms a closed loop trajectory, reducing the idle stroke by 70%.

[0060] After the welding robot is started according to the preset program, its welding gun is aimed at the outer ring of the vertical special-shaped nut 41 at a constant inclination angle; the extrusion head 31 maintains the rigid support generated by the clamping state, effectively suppressing welding thermal deformation; under the protection of argon gas, the molten droplets of welding wire form an annular molten pool along the joint between the special-shaped nut 41 and the pipe fitting 4; because all welding postures are unified and the gravity flow direction is consistent, the fluctuation range of the penetration depth is controlled within ±0.05mm, achieving continuous and dense welds in all positions; after welding is completed, the piston rod of the cylinder 3 retracts, the extrusion head 31 moves up to release the wedge effect, and the beam spring 223 drives the clamping block 22 to reset, and the workpiece can be removed without damage.

[0061] In this article, there are several points to note:

[0062] 1. The drawings of the embodiments of the present invention only relate to the structures related to the embodiments of the present invention. Other structures may refer to conventional designs.

[0063] 2. In the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other to form new embodiments.

[0064] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. A special-shaped nut welding tool, comprising: A positioner workbench (1), wherein the bottom of the positioner workbench (1) is driven to rotate by a positioner, and is characterized in that eight positioning platforms (2) are distributed in a ring near the edge of the positioner workbench (1), and a vertical cylinder (3) is provided at the bottom of the positioning platform (2), and the lower end of the cylinder (3) is vertically embedded in the installation groove of the positioner workbench (1) by bolts; the upper end of the positioning platform (2) is vertically clamped with a pipe fitting (4); each of the positioning platforms (2) is provided with an internal support device, and the internal support device The clamping is controlled by a cylinder (3); one side of the pipe fitting (4) is a special-shaped nut (41) to be welded, an auxiliary positioning frame (6) is provided between the positioning platform (2) and the edge of the positioner workbench (1), a positioning pin (61) is vertically slidably inserted in the auxiliary positioning frame (6), and the positioning pin (61) is pushed upward to determine the placement direction of the special-shaped nut (41) on the pipe fitting (4); an independent cylinder switch (5) is respectively provided on the positioner workbench (1) on one side of each cylinder (3).

2. A special-shaped nut welding tool according to claim 1, characterized in that: The inner support device comprises six rails (21) which are distributed in an annular manner at the bottom of the disc groove of the positioning platform (2). The rails (21) are distributed in a scattered manner along the diameter line of the positioning platform (2).

3. The special-shaped nut welding tool according to claim 1, characterized in that: The inner support device also includes a clamping block (22), a waist groove (222) and a beam spring (223). The clamping blocks (22) are also six in number. The clamping blocks (22) are fan-shaped structures. The bottom of the clamping block (22) is provided with a slide groove (221) that is slidably engaged with the rail (21). The middle part of the outer end arc surface of the clamping block (22) is provided with a waist groove (222). The beam spring (223) is set between the waist grooves (222) of the six clamping blocks (22). The beam spring (223) provides cohesive force for the clamping block (22). The upper end of the clamping block (22) is higher than the upper end of the positioning platform (2). The lower end of the inner cavity of the pipe (4) is ring-sheathed on the outside of the six clamping blocks (22).

4. The special-shaped nut welding tool according to claim 1, characterized in that: The inner support device also includes an extrusion head (31) and a threaded sleeve (311). The extrusion head (31) is a truncated cone structure that is wide at the top and narrow at the bottom. The extrusion head (31) is located between the six clamping blocks (22). The inner ends of the six clamping blocks (22) are inner concave structures that match the conical surfaces of the extrusion head (31). The lower end of the extrusion head (31) is a threaded sleeve (311). The lower end of the threaded sleeve (311) is threadedly connected to the upper end of the piston rod of the cylinder (3). The piston rod of the cylinder (3) drives the extrusion head (31) to move vertically. The extrusion head (31) moves downward, pressing the six clamping blocks (22) to move outward. The six clamping blocks (22) tighten the inner wall of the pipe fitting (4).

5. The special-shaped nut welding tool according to claim 1, characterized in that: The upper end of the positioning pin (61) is a Y-shaped head (62), and the width of the Y-shaped head (62) is consistent with the diameter of the special-shaped nut (41).

6. The control method of a special-shaped nut welding tool according to claim 1, characterized in that: The following steps are involved: Step 1: Debugging the TIG welding process parameters of the pipe fitting (4), welding current, argon gas flow rate and welding speed, and adjusting the welding robot program, setting the rotation angle and displacement speed of the robot welding gun, etc., so that the thread weld of each special-shaped nut (41) on the pipe fitting (4) is complete and continuous. Step 2: Place the non-interference end of the pipe fitting (4) into each positioning table (2) of the tooling. Eight similar products can be placed at the same time. First, use the positioning pin (61) to position the same special-shaped nut (41) to ensure that the direction and position to be welded are consistent. Step 3: Open the eight cylinders on the positioning platform (2) so that the end of the pipe (4) is clamped by the inner support device. Step 4: Make an appointment for the welding procedure of the corresponding product, click the green start button of the robot workstation, and the entire workbench rotates 45 degrees sideways from the horizontal state, so that the special-shaped nuts (41) are all vertically facing upwards to enter the welding posture. Step 5: Fine-tune the working angle, welding speed, and welding process parameters of the welding robot so that the welding wire on the outer ring of the special-shaped nut (41) is uniformly melted to form a stable molten pool, ensuring that the annular weld of each special-shaped nut (41) is complete, continuous, and dense.

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