Railway vehicle coupler yoke plate friction stir welding tool and welding method

Abstract

The present application relates to the technical field of welding tooling device, especially relates to a rail vehicle coupler plate friction stir welding tooling and a welding method, which comprises a supporting base and a limiting structure assembled at the top of the supporting base, and the supporting base comprises a bottom plate welded with a machine tool, the present application utilizes an outside tightening assembly, an external steel top, an inside tightening assembly and an internal steel top to form a bidirectional clamping structure, and simultaneously cooperates with an end limiting plate and an upper pressing assembly to realize complete rigid locking of five degrees of freedom of a workpiece in the longitudinal direction, the transverse direction and the vertical direction, the external steel top is placed on the support table surface of the vertical plate one and slides, ensures that the pressing force is vertically applied to the workpiece, eliminates the lateral component force, avoids the sliding of the clamping component, keeps the gap stable between the two profile butt joints during the whole welding process, inhibits the profile edge misalignment and displacement, reduces the welding seam pores and incomplete penetration defects, guarantees the performance of the key welding joint of the coupler plate and improves the product operation safety.

Description

Technical Field

[0001] This invention relates to the field of welding fixtures and equipment, and in particular to a friction stir welding fixture and welding method for a rail vehicle coupler plate. Background Technology

[0002] The coupler plate at the bottom of aluminum alloy passenger and freight cars in rail transit is a key load-bearing component used to connect adjacent carriages to form a complete train. The coupler plates are basically extruded aluminum alloy profiles with relatively high wall thickness. However, due to the limitations of the profile extrusion process, it is not possible to extrude the profile with the required cross-section in one go. Therefore, it is necessary to use welding to connect two symmetrical coupler plate profiles.

[0003] The current mainstream welding method is traditional MIG welding. However, because MIG welding is prone to welding defects such as porosity at the arc initiation end of the weld, has large welding deformation, and relatively low tensile strength, core components such as coupler plates that bear critical loads during train start-stop and braking are adopting the more advanced and stable welding method FSW. However, friction stir welding has very high requirements for the welding gap during the welding process. At the same time, because the large-diameter stirring head generates huge upsetting force during the welding process, taking a stirring head with a depth of 20 mm as an example, it can generate an upsetting force of about 30 kN during the welding process. This force will force the two profiles to move, resulting in excessive assembly gap and other misalignment problems, thus affecting the welding quality of friction stir welding. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a friction stir welding fixture and welding method for rail vehicle coupler plates. It solves the technical problem that the large-diameter stirring head generates a huge upsetting force during the welding process, which affects the welding quality of friction stir welding. The invention achieves the goal of ensuring that the upsetting force acts perpendicularly on the workpiece, eliminating lateral force components, avoiding slippage of clamping components, and maintaining a stable gap between the two profiles during the entire welding process.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a friction stir welding fixture and welding method for a rail vehicle coupler plate, comprising a support base and a limiting structure assembled on its top end; The support base includes a base plate welded to the machine tool, and vertical plates one welded to its left and right sides. Vertical plates two are welded to the base plate at both ends of the tooling length direction. A flat plate for supporting the hook plate to be welded is arranged horizontally at the top of vertical plate two. A horizontal plate is welded to vertical plate one. The limiting structure includes an outer tightening assembly installed on two vertical plates to apply a horizontal lateral tightening force from the outside of the workpiece, and an inner tightening assembly installed on the inner side of the vertical plate to achieve closed-loop control of the workpiece width. A pressing assembly is provided on both sides above the upper plate, which is horizontally mounted on the hook plate profile to be welded. An end tensioning assembly and an end limiting plate are respectively provided at both ends of the vertical plate for longitudinally limiting the two ends of the workpiece. The end tensioning assembly and the pressing assembly cooperate to achieve vertical pressing of the workpiece.

[0006] Preferably, the upright plates are arranged in pairs on the left and right sides of the base plate, and the upright plates are provided with multiple sets of assembly positioning square holes for installing the horizontal plates. The horizontal plates can be selected to be assembled into the assembly positioning square holes at different heights, such as the upper, middle and lower parts.

[0007] Preferably, the horizontal plate is provided with a movable interface for adjusting the position of the outer tightening assembly. Multiple sets of the outer tightening assembly are arranged along the length of the tooling. The outer tightening assembly includes a nut seat that is fitted inside the movable interface of the horizontal plate and a screw that is threaded inside it. The inner end of the screw has a circular base that slides on the vertical plate. An outer steel top that slides along the workpiece direction is fixed inside the circular base.

[0008] Preferably, the second upright plate has a movable limiting interface, and the inner tightening assembly includes a middle connecting rod that is snapped into the limiting interface. The two ends of the middle connecting rod are respectively machined with a forward thread and a reverse thread, and the two ends are respectively connected to a forward support head and a reverse support head. The forward support head and the reverse support head are cuboid in shape, which restricts the support head from rotating circumferentially with the middle connecting rod and only allows the support head to perform linear extension and retraction. The two ends of the inner tightening assembly abut against an inner steel top corresponding to the position of the outer steel top.

[0009] Preferably, the outer steel top is placed on the support platform of the upright plate and can slide along the support platform to move closer to or away from the workpiece. The inner side of the outer steel top is a contoured surface that matches the outer contour of the coupler plate profile. The inner steel top is arranged on the inner side of the two coupler plate profiles to be welded, and the outer side of the inner steel top is provided with a contoured surface that matches the inner wall of the coupler plate profile.

[0010] Preferably, the clamping assembly includes upper pressure plates located on both sides of the top of the upper plate. The upper pressure plates are thick steel plate components. U-shaped notches are opened at both ends of the upper pressure plates, and lifting lugs are installed in the middle of the upper pressure plates. The rods of the end tensioning assembly pass through the U-shaped notches to achieve a locking fit.

[0011] Preferably, the end tensioning assembly includes a second screw rod that passes upward through a U-shaped notch, a second nut seat that is threaded onto the upper end of the second screw rod, a pressure plate that is fixed to the bottom end of the second screw rod, and a mounting square hole that hangs on the force-bearing protrusion of the second upright plate. Tightening the second nut seat pulls the upper pressure plate downward.

[0012] Preferably, the upper plate has a groove for accommodating the welding boss of the coupler plate, and the end limiting plate is only provided at one end of the support base to prevent the longitudinal movement of the workpiece caused by the forward thrust of the stirring head.

[0013] A welding method for a friction stir welding fixture for a rail vehicle coupler plate, characterized by comprising the following steps: S1. Hoist the coupler plate profile into the mounting fixture, and complete the longitudinal positioning by fitting the end of the workpiece with the end limit plate. S2. Assemble the outer tightening assembly and the outer steel top to complete the pre-tightening of the workpiece on the outside. Insert the inner steel top, assemble the inner tightening assembly, rotate the middle connecting rod, and rely on the positive and negative threads to open the inner steel top in both directions. Measure the workpiece width in real time until the workpiece width meets the process requirements. S3. Place the hoisting and clamping assembly above the workpiece, insert the end tensioning assembly rod into the U-shaped notch, and lock the nut seat two to complete the vertical clamping of the workpiece. S4. Insert the stirring head to a depth of mm, pre-path the probe along the weld seam, and fine-tune the outer tightening component according to the trajectory deviation so that the stirring head trajectory is aligned with the center of the weld seam and all tightening components are fully locked. S5. Perform mm shallow friction stir welding, remove burrs, replace with mm deep stirring head to complete deep welding, remove burrs after welding, loosen all components of the tooling, and take out the finished workpiece.

[0014] By means of the above technical solution, the present invention provides a friction stir welding fixture and welding method for railway vehicle coupler plates, which has at least the following beneficial effects: 1. This invention uses bidirectional rigid clamping to resist the 30KN forging force of the stirring head, thereby improving weld quality. The bidirectional clamping structure, consisting of an outer tightening component, an outer steel top, an inner tightening component, and an inner steel top, along with an end limiting plate and an upper pressing component, achieves complete rigid locking of the workpiece in five degrees of freedom: longitudinal, transverse, and vertical. The outer steel top slides on the support platform of the vertical plate, ensuring that the clamping force acts perpendicularly on the workpiece, eliminating lateral forces, and preventing slippage of the clamping components. Throughout the welding process, the gap between the two profiles remains stable, suppressing misalignment and displacement of the profiles, reducing weld porosity and incomplete penetration defects, ensuring the performance of key weld joints in the coupler plate, and improving product operational safety.

[0015] 2. This invention uses an internal tightening assembly with a central connecting rod featuring bidirectional threads for both forward and reverse rotation. Rotating the connecting rod allows for simultaneous bidirectional opening of the internal steel tops on both sides, forming an internal and external clamping mechanism with the external steel tops. During clamping, the workpiece width can be measured and locked in real time, directly controlling the finished width of the coupler plate within the process tolerance range before welding. This significantly reduces the probability of dimensional deviations after welding, reduces the need for thick plate correction processes, lowers the rework and scrap rate, and is suitable for mass production.

[0016] 3. This invention, by mounting the external steel top on a support platform, allows for direct sliding forward and backward movement during clamping and disassembly, eliminating the need for repeated hoisting of the heavy steel top. The clamping assembly is equipped with lifting lugs for convenient overall hoisting and transportation. The symmetrical structure of the upper pressure plate allows it to be flipped over and reused after deformation under pressure, reducing on-site hoisting of large components, shortening clamping time, and reducing the labor intensity of operators. It also extends the service life of the clamping assembly and reduces the cost of tooling and spare parts.

[0017] 4. This invention features multiple sets of assembly positioning square holes on the upright plate, allowing the horizontal plate to be installed at different heights (upper, middle, and lower). The horizontal plate has a long, narrow movable interface, and the outer tightening component can slide freely along the length of the tooling to adjust the tightening point. The steel top adopts a replaceable contoured structure. The same set of standard tooling can be adapted to coupler plate profiles with various cross-sectional shapes, eliminating the need to develop tooling separately for each product and reducing the overall cost of tooling design, processing, and storage.

[0018] 5. This invention uses an end limiting plate to rigidly block the welding direction of the coupler plate profile by arranging the tooling at only one end. This can resist the longitudinal thrust brought by the advance of the stirring head, prevent the workpiece from moving along the welding direction, and ensure that the welding trajectory of the stirring head does not deviate, thus guaranteeing the welding quality of the arc start and arc end segments of the weld. Attached Figure Description

[0019] The accompanying drawings, which are provided to further illustrate this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application.

[0020] In the attached diagram: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the support base structure of the present invention; Figure 3 This is a schematic diagram of the limiting structure of the present invention; Figure 4 This is a schematic diagram showing the installation positions of the outer tightening assembly, the outer steel top, and the inner steel top of the present invention. Figure 5 This is a schematic diagram of the inner tightening assembly structure of the present invention; Figure 6 This is a schematic diagram of the outer tightening assembly structure of the present invention; Figure 7 This is a schematic diagram of the clamping component structure of the present invention; Figure 8 This is a schematic diagram of the end tensioning assembly structure of the present invention; Figure 9 This is an exploded view of the entire invention; Figure 10 This is a schematic diagram of the upright plate structure of the present invention; Figure 11 This is a schematic diagram of the second vertical plate structure of the present invention.

[0021] In the diagram: 1. Support base; 11. Vertical plate one; 12. Vertical plate two; 13. Base plate; 14. Upper plate; 15. Horizontal plate; 2. Limiting structure; 21. Outer tightening assembly; 201. Outer steel top; 202. Inner steel top; 211. Screw one; 212. Nut seat one; 213. Circular base; 22. Inner tightening assembly; 221. Reverse rotation support head; 222. Intermediate connecting rod; 223. Forward rotation support head; 23. Pressing assembly; 231. Upper pressure plate; 232. U-shaped notch; 233. Lifting lug; 24. End tensioning assembly; 241. Screw two; 242. Nut seat two; 243. Pressure plate; 244. Mounting square hole; 25. End limiting plate. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1 To address the shortcomings of existing technologies, this invention provides a friction stir welding fixture and method for railway vehicle coupler plates. It solves the technical problem in existing technologies where the large-diameter stirring head generates enormous upsetting force during welding, affecting the welding quality of friction stir welding. This invention achieves the goal of ensuring the upsetting force acts perpendicularly to the workpiece, eliminating lateral forces, preventing slippage of clamping components, and maintaining a stable gap between the two profiles during the entire welding process. Please refer to... Figure 1 - Figure 11 The friction stir welding fixture and welding method for the coupler plate of the rail vehicle includes a support base 1 and a limiting structure 2 assembled on its top; the two coupler plate profiles are respectively hoisted into the mounting fixture and placed on the upper plate 14, the welding boss of the profile falls into the groove of the upper plate 14, and one end of the workpiece in the length direction is attached to the end limiting plate 25 to complete the longitudinal positioning.

[0024] The support base 1 includes a base plate 13 welded to the machine tool. The base plate 13 is located at the bottom of the tooling, serving as the assembly base for the entire tooling set, providing overall rigidity, enabling connection between the tooling and the welding machine tool, and ensuring the tooling's datum flatness. It also includes vertical plates 11 welded to its left and right sides. The vertical plates 11 are welded and fixed to the left and right sides of the base plate 13. Multiple support platforms are machined on the inner side of the vertical plates 11, providing sliding support for the external steel top 201, bearing the lateral tightening reaction force of the external tightening assembly 21, providing sliding support for the external steel top 201, and providing multi-height installation interfaces compatible with different shaped coupler plate profiles. For details, please refer to the appendix. Figure 10 The base plate 13 is welded with two vertical plates 12 located at both ends along the length of the tooling. The vertical plates 12 have mounting interfaces and movement limit interfaces for the inner tightening assembly 22. A force-bearing boss is provided at the upper end of the vertical plates 12, serving as a force-bearing fulcrum for the end tensioning assembly 24. This boss can constrain the circumferential rotation of the inner tightening assembly 22, allow its longitudinal sliding adjustment, and withstand the tensioning reaction force of the end tensioning assembly 24. For details, please refer to the appendix. Figure 11 The top of the second vertical plate 12 is horizontally arranged with an upper plate 14 to support the hook plate to be welded, and a horizontal plate 15 is horizontally welded on the first vertical plate 11. Because the friction stir welding head generates a huge forging force of approximately 30 kN, the workpiece is prone to lateral displacement, widening of assembly gaps, and misalignment, resulting in weld porosity and incomplete penetration defects. To solve this problem, such as... Figure 1 - Figure 9 As shown, the limiting structure 2 includes an outer tightening assembly 21 installed on two vertical plates 11 to apply a horizontal lateral tightening force from the outside of the workpiece, resisting the 30KN upsetting force of friction stir welding and preventing the profile from shifting outward; and an inner tightening assembly 22 installed on the inner side of the vertical plate 12 to achieve closed-loop control of the workpiece width dimension. A pressing assembly 23 is horizontally mounted on both sides above the upper plate 14, supporting the hook plate profile to be welded. End tensioning assemblies 24 for longitudinally limiting the two ends of the workpiece are respectively installed at both ends of the vertical plate 12. The end limiting plate 25, end tensioning assembly 24 and pressing assembly 23 cooperate to achieve vertical clamping of the workpiece. The outer torsion assembly 21 and the outer steel top 201 and the inner torsion assembly 22 and the inner steel top 202 are set to perform bidirectional rigid clamping of the workpiece. All five degrees of freedom of the workpiece are rigidly locked. The steel top slides on the vertical plate support platform. The clamping force acts vertically on the workpiece, eliminating the lateral component force. It can resist the large upsetting force of the stirring head. The assembly gap of the two profiles is stable throughout the welding process, avoiding misalignment, ensuring the internal quality of the weld, and reducing the welding defect rate.

[0025] Specifically, such as Figure 1 - Figure 2As shown, upright plates 11 are arranged in pairs on the left and right sides of the base plate 13. Upright plates 11 have multiple sets of assembly positioning square holes for installing horizontal plates 15. Horizontal plates 15 can be selected to be assembled into assembly positioning square holes at different heights (upper, middle, and lower). Horizontal plates 15 are equipped with upper, middle, and lower multi-height assembly interfaces. The steel top adopts a contour-following replaceable structure. The tightening assembly can slide and adjust along the long groove of horizontal plate 15. One set of tooling is compatible with various cross-section coupler plate profiles. The tooling has strong versatility and reduces the manufacturing cost of multiple sets of tooling.

[0026] The horizontal plate 15 has a movable interface for adjusting the position of the outer tightening assembly 21. Multiple sets of the outer tightening assembly 21 are arranged along the length of the tooling. The outer tightening assembly 21 includes a nut seat 212 that is fitted into the movable interface of the horizontal plate 15 and a screw 211 threaded inside it. The inner end of the screw 211 has a circular base 213 that slides on the vertical plate 11. An external steel top 201 that slides along the workpiece direction is fixed inside the circular base 213 to concentrate and tighten the screw 211. Force is converted into uniform pressure on the contoured surface, avoiding local damage to the workpiece. During welding, it can slide along the support platform, and during disassembly, it can be moved directly backward without repeated hoisting. According to the cross-section of the coupler plate profile, select a suitable height position on the horizontal plate 15, install the outer tightening component 21 nut seat 212 into the moving interface of the horizontal plate 15, slide it to the tightening point corresponding to the length of the workpiece, place the outer steel top 201 on the support platform of the vertical plate 11, and rotate the screw 211 to push the outer steel top 201 to fit against the outer surface of the coupler plate, completing the outer pre-tightening.

[0027] Traditional tooling only clamps from the outside, making it impossible to directly control the width of the finished coupler plate. This results in post-weld defects exceeding tolerances and significant difficulty in correction. To address this issue, such as... Figure 1 - Figure 5 As shown, the upright plate 212 has a movable limiting interface. The inner tightening component 22 includes an intermediate connecting rod 222 that is inserted into the limiting interface. The two ends of the intermediate connecting rod 222 are respectively machined with a forward thread and a reverse thread, and the two ends are respectively connected to a forward support head 223 and a reverse support head 221. The forward support head 223 and the reverse support head 221 are cuboid in shape, which restricts the support head from rotating circumferentially with the intermediate connecting rod 222 and only allows the support head to perform linear extension and retraction. The two ends of the inner tightening component 22 are respectively abutted by an inner steel top 202 corresponding to the position of the outer steel top 201. The tooling is equipped with an inner tightening component 22 with forward and reverse threads, which synchronously opens the inner steel top 202 in both directions. The inner and outer steel tops cooperate to directly control the width of the workpiece in a closed loop. The finished product size is locked during the welding and clamping stage. The product width is directly guaranteed during the clamping and welding process, reducing the post-weld correction process and improving the finished product size qualification rate.

[0028] When the intermediate connecting rod 222 is rotated, the forward rotation support head 223 and the reverse rotation support head 221 extend outward simultaneously, opening the internal steel top 202 in both directions, realizing closed-loop control of the workpiece width dimension. The cuboid support head is constrained by the vertical plate 12, and the support head only moves in a straight line and does not rotate when the connecting rod rotates.

[0029] The internal steel top 202 is located inside the two coupler plate profiles. Multiple internal tightening components 22 are sequentially installed from the mounting interface of the second vertical plate 12. The rectangular forward rotation support head 223 and the reverse rotation support head 221 are engaged in the movement limiting groove of the second vertical plate 12 to prevent the support head from rotating with the connecting rod. The rotating intermediate connecting rod 222 drives the forward rotation support head 223 and the reverse rotation support head 221 to push the internal steel top 202 on both sides outward simultaneously by relying on the positive and negative T-shaped threads at both ends. The width of the finished workpiece is measured in real time, and the intermediate connecting rod 222 is continuously rotated until the width of the workpiece meets the process dimension requirements of the drawing. The rotation is stopped, and the internal support of the workpiece and the locking of the finished size are completed.

[0030] The inner tightening component 22 opens synchronously in both directions, the inner steel top 202 pushes the profile outward, and the outer steel top 201 bears the reaction force. The inner and outer steel tops together clamp the profile, locking the width of the two profiles and counteracting the tendency of the profile to open and misalign during the welding process.

[0031] Example 2 Based on Example 1, such as Figure 1 - Figure 5 As shown, the outer steel top 201 is placed on the support platform of the upright plate 11 and can slide towards and away from the workpiece along the support platform. The inner side of the outer steel top 201 is a contoured surface that matches the outer contour of the coupler plate profile. The inner steel top 202 is arranged on the inner side of the two coupler plate profiles to be welded. The outer side of the inner steel top 202 is provided with a contoured surface that matches the inner wall of the coupler plate profile. The two sets of inner steel tops 202 are located on both sides of the weld and the inner side of the workpiece, respectively, between the coupler plate profile and the inner tightening assembly 22. They evenly transmit the bidirectional spreading force of the inner tightening assembly 22 to the inner side of the profile and work together with the outer steel top to control the finished width of the workpiece.

[0032] The workpiece is clamped and locked vertically; please refer to the appendix for details. Figure 7 As shown, the clamping assembly 23 includes upper pressure plates 231 located on both sides of the top of the upper plate 14. The upper pressure plates 231 are thick steel plate components. U-shaped notches 232 are opened at both ends of the upper pressure plates 231, and lifting lugs 233 are installed in the middle of the upper pressure plates 231. The rods of the end tensioning assembly 24 are inserted into the U-shaped notches 232 to achieve a locking fit. The clamping assembly 23 is erected above the workpiece. The screw 241 of the end tensioning assembly 24 is inserted into the U-shaped notches 232 at both ends of the upper pressure plates 231. The nut seat 242 is tightened, and the upper pressure plates 231 are pulled down to apply a vertical downward clamping force to the coupler plate profile to eliminate the risk of vertical movement of the workpiece.

[0033] The end tensioning assembly 24 includes a screw 241 that passes upward through a U-shaped notch 232. A nut seat 242 is threaded onto the upper end of the screw 241. A pressure plate 243 is fixed to the bottom end of the screw 241. A square hole 244 is provided on the pressure plate 243 to hang on the force-bearing protrusion of the upright plate 212. Tightening the nut seat 242 pulls the upper pressure plate 231 downward.

[0034] Insert a 5mm deep stirring head, pre-pathetize the stirring head probe along the weld seam, observe the deviation between the probe trajectory and the center of the weld seam, fine-tune the screws of the outer tightening assembly 21 on both sides, correct the left and right positions of the profile, ensure that the running trajectory of the stirring head is strictly aligned with the center of the two profiles, tighten all threaded pairs, and complete the omnidirectional rigid clamping of the workpiece.

[0035] The first 5mm shallow friction stir welding is performed. The shallow welding first forms a preliminary weld joint, which disperses the huge upsetting force of about 30KN generated by the subsequent deep stirring head, inhibits the opening of the assembly gap, removes the weld burrs, replaces the 20mm deep stirring head, and performs the second layer of deep welding to complete the full thickness friction stir welding on the front of the coupler plate. After welding, the burrs are cleaned, all tightened components are loosened, and the inner steel top 202 and the outer steel top 201 slide backward along the vertical plate support platform to allow the finished workpiece to be lifted out.

[0036] The upper plate 14 has a groove for accommodating the welding boss of the coupler plate. The end limiting plate 25 is only set at one end of the support base 1 to prevent the longitudinal movement of the workpiece caused by the forward thrust of the stirring head. During the friction stir welding process, the stirring head will generate a huge horizontal upsetting thrust. The tooling implements rigid constraints in five directions: longitudinal, transverse inner and outer, and vertical. The positive tooling adds an inner bidirectional support mechanism to achieve controllable width of the finished product during the welding process. A layered process of 5mm shallow pre-welding and 20mm deep welding is adopted to reduce the damage to the assembly gap caused by the instantaneous upsetting force of the deep stirring head.

[0037] A welding method for a friction stir welding fixture for a rail vehicle coupler plate, characterized by comprising the following steps: S1. Hoist the coupler plate profile into the mounting fixture, and the end of the workpiece is attached to the end limiting plate 25 to complete the longitudinal positioning. S2. Assemble the outer tightening assembly 21 and the outer steel top 201 to complete the pre-tightening of the workpiece on the outside. Insert the inner steel top 202, assemble the inner tightening assembly 22, rotate the intermediate connecting rod 222, and rely on the positive and negative threads to open the inner steel top 202 in both directions. Measure the workpiece width in real time until the workpiece width meets the process requirements. S3. The hoisting and clamping assembly 23 is placed above the workpiece, the end tensioning assembly 24 rod is inserted into the U-shaped notch 232, and the locking nut seat 242 completes the vertical clamping of the workpiece. S4. Insert a 5mm deep stirring head, pre-pathetize the probe along the weld seam, and fine-tune the outer tightening component 21 according to the trajectory deviation so that the stirring head trajectory is aligned with the center of the weld seam and all tightening components are fully locked. S5. Perform 5mm shallow friction stir welding, remove burrs, replace with a 20mm deep stirring head to complete deep welding, remove burrs after welding, loosen all components of the tooling, and take out the finished workpiece.

[0038] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0039] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A friction stir welding fixture for a railway vehicle coupler plate, characterized in that: It includes a support base (1) and a limiting structure (2) assembled on its top; The support base (1) includes a base plate (13) welded to the machine tool, and a first vertical plate (11) welded to its left and right sides. The base plate (13) is welded with a second vertical plate (12) located at both ends of the tooling length direction. The top of the second vertical plate (12) is horizontally arranged with an upper plate (14) supporting the hook plate to be welded. A horizontal plate (15) is welded to the first vertical plate (11). The limiting structure (2) includes an outer tightening assembly (21) installed on two upright plates (11) to apply a horizontal lateral tightening force from the outside of the workpiece, and an inner tightening assembly (22) installed on the inside of the upright plate (12) to achieve closed-loop control of the workpiece width dimension. A pressing assembly (23) is provided on both sides above the upper plate (14) and is horizontally mounted on the hook plate profile to be welded. An end tensioning assembly (24) and an end limiting plate (25) are provided at both ends of the upright plate (12) to longitudinally limit the two ends of the workpiece. The end tensioning assembly (24) and the pressing assembly (23) cooperate to achieve vertical pressing of the workpiece.

2. The friction stir welding method for a railway vehicle coupler plate according to claim 1, characterized in that: The upright plates (11) are arranged in pairs on the left and right sides of the base plate (13). The upright plates (11) have multiple sets of assembly positioning square holes for installing the horizontal plates (15). The horizontal plates (15) can be selected to be installed in the assembly positioning square holes at different heights, such as the upper, middle and lower parts.

3. The friction stir welding fixture for a rail vehicle coupler plate according to claim 1, characterized in that: The horizontal plate (15) is provided with a movable interface for the outer tightening assembly (21) to slide and adjust its position; The outer tightening assembly (21) is provided in multiple sets along the length of the tooling. The outer tightening assembly (21) includes a nut seat (212) that is clamped inside the moving interface of the horizontal plate (15) and a screw (211) that is threaded inside it. The inner end of the screw (211) has a circular base (213) that slides on the vertical plate (11). The inner side of the circular base (213) has an outer steel top (201) that slides along the workpiece direction.

4. The friction stir welding fixture for a rail vehicle coupler plate according to claim 3, characterized in that: The second vertical plate (12) has a movable limiting interface. The inner tightening assembly (22) includes an intermediate connecting rod (222) that is inserted into the limiting interface. The two ends of the intermediate connecting rod (222) are respectively machined with a forward thread and a reverse thread, and the two ends are respectively connected to a forward support head (223) and a reverse support head (221). The forward support head (223) and the reverse support head (221) are rectangular in shape, which restricts the support head from rotating circumferentially with the intermediate connecting rod (222) and only allows the support head to perform linear extension and retraction. The two ends of the inner tightening assembly (22) are respectively abutted against an inner steel top (202) corresponding to the position of the outer steel top (201).

5. The friction stir welding fixture for a rail vehicle coupler plate according to claim 4, characterized in that: The outer steel top (201) is placed on the support platform of the upright plate (11) and can slide along the support platform to move closer to and away from the workpiece. The inner side of the outer steel top (201) is a contour surface that matches the outer contour of the coupler plate profile. The inner steel top (202) is arranged on the inner side of the two coupler plate profiles to be welded. The outer side of the inner steel top (202) is provided with a contour surface that matches the inner wall of the coupler plate profile.

6. The friction stir welding fixture for a rail vehicle coupler plate according to claim 1, characterized in that: The clamping assembly (23) includes upper pressure plates (231) located on both sides of the top of the upper plate (14). The upper pressure plates (231) are thick steel plate components. U-shaped notches (232) are opened at both ends of the upper pressure plates (231), and lifting lugs (233) are installed in the middle of the upper pressure plates (231). The rods of the end tensioning assembly (24) are inserted into the U-shaped notches (232) to achieve a locking fit.

7. The friction stir welding fixture and welding method for a rail vehicle coupler plate according to claim 1, characterized in that: The end tensioning assembly (24) includes a screw rod (241) that passes upward through a U-shaped notch (232). The upper end of the screw rod (241) is threaded with a nut seat (242). The bottom end of the screw rod (241) is fixed with a pressure plate (243). The pressure plate (243) has a mounting square hole (244) that hangs on the force-bearing boss of the upright plate (12). Tightening the nut seat (242) pulls the upper pressure plate (231) downward.

8. The friction stir welding fixture for a rail vehicle coupler plate according to claim 1, characterized in that: The upper plate (14) has a groove for accommodating the welding boss of the hook plate. The end limiting plate (25) is only set at one end of the support base (1) to prevent the longitudinal movement of the workpiece caused by the forward thrust of the stirring head.

9. A welding method using the friction stir welding fixture for a rail vehicle coupler plate as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. The cross-linked plate profile is hoisted into the mounting fixture, and the end of the workpiece is attached to the end limiting plate (25) to complete the longitudinal positioning. S2. Assemble the outer tightening assembly (21) and the outer steel top (201) to complete the pre-tightening of the workpiece on the outside. Install the inner steel top (202), assemble the inner tightening assembly (22), rotate the middle connecting rod (222), and rely on the positive and negative threads to open the inner steel top (202) in both directions. Measure the workpiece width in real time until the workpiece width meets the process requirements. S3. The hoisting and clamping assembly (23) is placed above the workpiece, and the end tensioning assembly (24) rod is inserted into the U-shaped notch (232). The locking nut seat (242) completes the vertical clamping of the workpiece. S4. Insert a 5mm deep stirring head, pre-path the probe along the weld seam, and fine-tune the outer tightening component (21) according to the trajectory deviation so that the stirring head trajectory is aligned with the center of the weld seam and all tightening components are fully locked. S5. Perform 5mm shallow friction stir welding, remove burrs, replace with a 20mm deep stirring head to complete deep welding, remove burrs after welding, loosen all components of the tooling, and take out the finished workpiece.

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