Friction-stir welding tool for circular seam at bottom of carrier rocket storage tank and using method of friction-stir welding tool

Abstract

The invention discloses a friction stir welding tool for a circular seam at the bottom of a carrier rocket storage tank and a using method, and belongs to the technical field of carrier rocket storage tanks. The tool comprises an inner supporting part, an outer pressing part, a fork-shaped ring workpiece, a circular ring workpiece, a top cover workpiece and a short shell workpiece, and the fork-shaped ring workpiece, the circular ring workpiece, the top cover workpiece and the short shell workpiece are all arranged on the inner supporting part; the inner supporting part is used for adjusting the position of the workpiece corresponding to each circular seam and providing inner jacking force for at least one part of the workpiece, and the outer pressing part is used for providing outer pressure for the workpiece corresponding to each welding seam. During pre-welding milling and friction stir welding of the fork-shaped ring circular seam and the top cover circular seam, the workpieces are pressed all the time, and the precision of the gap amount of the welding edges and the milling amount after pre-welding milling of the two workpieces is guaranteed through related structures.

Description

Technical Field

[0001] The present invention belongs to the technical field of launch vehicle tanks, and particularly relates to a friction stir welding tooling for the bottom circumferential seam of a launch vehicle tank. Background Art

[0002] At present, the existing friction stir welding tooling for the bottom circumferential seam of a launch vehicle tank mainly consists of an inner support part and an outer pressing part.

[0003] For the motion mechanism in the inner support part, a pneumatic solution is preferably adopted as much as possible, and an electric solution is adopted when the pneumatic solution cannot be realized due to large forces, so as to reduce the design difficulty and manufacturing cost increase of the conductive slip ring caused by the number of cables. For example, for the inner top pressing mechanism of the fork-shaped ring circumferential seam, since sufficient top pressing force for the welded parts needs to be ensured within a limited space, the moving mechanism cannot adopt a cylinder pneumatic control linear moving mechanism to drive the welding backing plate, but adopts a multi-group (6 groups or more, different numbers for different specifications of tank bottoms) servo motor control linear moving mechanism to drive the welding backing plate. The disadvantages of this solution mainly include: 1. The welding backing plate is designed as an annular structure, and the surface shape of the part in contact with the two welding edges needs to be as close as possible to the surface shapes of the two welding edges (the inner surface of the tank bottom is an ellipsoidal surface or a spherical surface). The mobile welding backing plate generally adopts a multi-group (6 groups or more) servo motor control linear moving mechanism to drive the welding backing plate to move horizontally in a straight line. When the multi-group annular welding backing plates are pressed against the two welding annular edges, a high synchronous control accuracy of the multi-group servo motors needs to be ensured.

[0004] 2. For the multi-group mobile welding backing plate top pressing mechanisms of the fork-shaped ring circumferential seam and the lock bottom circumferential seam, the relevant designs of the circular ring lifting mechanism for the fork-shaped ring circumferential seam lifting and the top cover lifting mechanism for the top cover circumferential seam lifting also need to be considered, which occupies a large amount of space and has great design difficulty within a limited space.

[0005] 3. The friction stir welding tooling for the bottom circumferential seam is installed on the circumferential seam turntable, and the circumferential seam turntable rotates to realize the circumferential continuous rotation of workpiece milling and welding. The multi-group mobile welding backing plate mechanisms, lifting mechanisms, relevant motors and sensor cables of the fork-shaped ring circumferential seam and the lock bottom circumferential seam realize the continuous rotation of the circumferential seam turntable through the conductive slip ring installed in the middle of the circumferential seam turntable. The number of cables is large, and the excessive cables cause a significant increase in the design difficulty and manufacturing cost of the conductive slip ring.

[0006] For the circular ring outer pressing component in the outer pressing part tooling, it is installed on the upper side of the middle of the circular ring die, and is used for outer pressing of the large end of the circular ring and outer pressing of the small end of the circular ring. The disadvantages of this solution are mainly as follows: 1. It occupies the installation space of the top cover workpiece, and the top cover without a central hole cannot be used, resulting in the inability to weld the circumferential seam of the top cover without a central hole (i.e., the small end of the circular ring and the large end of the top cover).

[0007] 2. The middle part of the ring die blank is occupied, and the top cover cannot be lifted or lowered, making it impossible to perform milling before welding the small end of the ring and the large end of the top cover. The solution is to use a separate tooling to achieve the welding of the top cover without a central hole. At the same time, different toolings are required for different specifications of the bottom of the box and different diameters of the top cover, resulting in complex operations, low efficiency, complex tooling structure, increased tooling cost, etc., thus increasing the manufacturing cost of the bottom of the box welding.

[0008] Therefore, a box bottom circumferential seam friction stir welding tooling that is as universal as possible is needed, with as few servo motors as possible in the inner support part; the circular ring outer pressing component in the outer pressing part of the tooling realizes the outer pressing of the large end and the small end of the circular ring in the same state, as well as the outer pressing of different diameters of the top cover and different types of the top cover under different specifications of the bottom of the box, to solve this problem.

[0009] The information disclosed in this background art section is only intended to enhance the understanding of the overall background of the present invention and should not be regarded as an admission or any form of suggestion that this information constitutes the prior art known to those of ordinary skill in the art. Summary of the Invention

[0010] In order to solve the technical problems existing in the inner support part and the outer pressing part of the box bottom circumferential seam friction stir welding tooling of the launch vehicle fuel tank in the above-mentioned prior art, a method for using a box bottom circumferential seam friction stir welding tooling of the launch vehicle fuel tank is provided.

[0011] In a first aspect, the present invention provides a box bottom circumferential seam friction stir welding tooling for a launch vehicle fuel tank, including the following steps: The box bottom circumferential seam friction stir welding tooling for a launch vehicle fuel tank includes: an inner support part and an outer pressing part connected to the inner support part, and is characterized in that it further includes: a fork-shaped ring workpiece, a circular ring workpiece, a top cover workpiece and a short shell workpiece. A fork-shaped ring circumferential seam is constructed by the small end of the fork-shaped ring workpiece and the large end of the circular ring workpiece, a top cover circumferential seam is constructed by the small end of the circular ring workpiece and the large end of the top cover workpiece, and a bottom locking circumferential seam is constructed by the outer cylindrical step surface of the fork-shaped ring workpiece and the lower end of the short shell workpiece; The fork-shaped ring workpiece, the circular ring workpiece, the top cover workpiece and the short shell workpiece are all arranged on the inner support part; The inner support part is used to adjust the positions of the workpieces corresponding to each circumferential seam and provide an inner top force for at least some of the workpieces, while the outer pressing part provides an outer pressure for the workpieces corresponding to each weld seam; the outer pressure can form a clamping force with the inner top force for clamping the workpieces.

[0012] In some embodiments, the outer pressing part includes outer pressing mechanisms corresponding to multiple circumferential seam weldings, the inner support part includes a support mechanism, a position adjustment mechanism and a circumferential seam inner tightening mechanism, each circumferential seam is equipped with the support mechanism and the position adjustment mechanism, and at least some of the circumferential seams are equipped with the circumferential seam inner tightening mechanism; Among them, the support mechanism is used to assemble each workpiece, the position adjustment mechanism is used to adjust the position of the workpiece, and the circumferential seam inner pressing mechanism is used to provide an inner pressing force for the workpiece corresponding to the weld seam.

[0013] In some embodiments, during the milling before circumferential seam welding, the fork-shaped ring workpiece, the circular ring workpiece, and the top cover workpiece are all adjusted to the corresponding milling positions through the corresponding position adjustment mechanisms; and During circumferential seam welding, the fork-shaped ring workpiece, the circular ring workpiece, the top cover workpiece, and the short shell workpiece are all adjusted to the corresponding circumferential seam welding positions through the corresponding position adjustment mechanisms. Each circumferential seam inner pressing mechanism provides an inner pressing force for the workpiece corresponding to the weld seam, and the outer pressing mechanism provides an outer pressure for the workpiece corresponding to the circumferential seam welding.

[0014] In some embodiments, the inner support part includes a tooling base, a fork-shaped ring mounting seat mechanism, a die holder lifting mechanism, a fork-shaped ring circumferential seam inner pressing mechanism, a circular ring die holder, and a top cover circumferential seam inner pressing mechanism; The tooling base is used to support the rest of the inner support part; the fork-shaped ring mounting seat mechanism is used for leveling and installing and fixing the fork-shaped ring workpiece and is arranged on the tooling base; the circular ring inner die holder is used to assemble the circular ring workpiece and the top cover workpiece and is arranged on the die holder lifting mechanism; the die holder lifting mechanism is arranged on the tooling base and is used for the overall lifting of the circular ring die holder; the fork-shaped ring circumferential seam inner pressing mechanism is arranged on the fork-shaped ring mounting seat and is used for inner pressing of the small end of the fork-shaped ring workpiece and the large end of the circular ring workpiece during friction stir welding of the fork-shaped ring circumferential seam; the top cover circumferential seam inner pressing mechanism is installed on the circular ring die holder and is used for inner pressing of the small end of the circular ring workpiece and the large end of the top cover workpiece during friction stir welding of the top cover circumferential seam; Among them, the tooling base, the fork-shaped ring mounting seat mechanism, and the circular ring die holder as a whole are all components of the support mechanism, and the die holder lifting mechanism is a component of the position adjustment mechanism.

[0015] In some embodiments, the fork-shaped ring circumferential seam inner pressing mechanism includes a double fork-shaped ring inner pressing motor, a gear transmission mechanism, and a workpiece tightening and loosening action execution mechanism. The gear transmission mechanism includes a gear set and a fork-shaped ring inner pressing turntable. The workpiece tightening and loosening control action execution mechanism includes multiple sets of fork-shaped ring welding pads. All the fork-shaped ring welding pads form a complete circumferential welding inner pressing ring structure. The double fork-shaped ring inner pressing motor drives the fork-shaped ring inner pressing turntable in the gear transmission mechanism to rotate, driving the fork-shaped ring welding pads in the workpiece tightening and loosening action execution mechanism to move radially synchronously to control the tightening and loosening of the inner sides of the small end of the fork-shaped ring workpiece and the large end of the circular ring workpiece.

[0016] In some embodiments, the number of the inner pressing mechanisms for the top cover circumferential seam is multiple, and each of the inner pressing mechanisms for the top cover circumferential seam includes: an inner pressing screw lift for the top cover circumferential seam, a pressing transmission mechanism, and a guiding assembly. The guiding assembly includes a top cover welding backing plate, and all the top cover welding backing plates form a complete circumferential welding pressing ring structure. All the inner pressing mechanisms for the top cover circumferential seam drive the top cover welding backing plates in the guiding assembly to move synchronously through the pressing transmission mechanism to control the tightness of the inner sides of the small end of the circular ring workpiece and the large end of the top cover workpiece.

[0017] In some embodiments, the external pressing part includes a fork-shaped ring external pressing mechanism, a large end external pressing mechanism for the circular ring, a small end external pressing mechanism for the circular ring, a moving gantry, a gantry pressing mechanism, a lifting pressing mechanism, a large top cover external pressing mechanism, and a lock bottom welding external pressing mechanism.

[0018] In some embodiments, the top cover workpiece includes a small-sized top cover workpiece and a large-sized top cover workpiece.

[0019] In a second aspect, the present invention provides a method for using a friction stir welding tooling for the bottom circumferential seam of a launch vehicle propellant tank, which is applicable to the friction stir welding tooling for the bottom circumferential seam of a launch vehicle propellant tank described in any one of the first aspects, and includes the following steps: First, perform pre-welding milling on the fork-shaped ring circumferential seam and the top cover circumferential seam through the inner support part. During milling, it is necessary to adjust the positions of the fork-shaped ring workpiece, the circular ring workpiece, and the top cover workpiece to the corresponding milling positions through the inner support part; Then, perform friction stir welding on the fork-shaped ring circumferential seam, the top cover circumferential seam, and the lock bottom circumferential seam through the inner support part and the external pressing part. During friction stir welding, it is necessary to adjust the positions of the fork-shaped ring workpiece, the circular ring workpiece, the top cover workpiece, and the short shell workpiece to the corresponding circumferential seam welding positions through the inner support part. The inner support part also provides an inner pressing force for the workpiece corresponding to the circumferential seam welding, while the external pressing part provides an external pressure for the workpiece corresponding to the circumferential seam welding; Finally, complete the welding of all circumferential seams.

[0020] Compared with the prior art, the technical effects achieved by the present invention are as follows: When the present invention is used for friction stir welding of the bottom circumferential seam of a rocket tank, it has sufficient strength and stiffness. It ensures a small deformation amount of the welding edge, a pre-welding gap, and a pre-welding misalignment amount of the two welded parts, improving the welding quality and welding strength of the friction stir weld. The welded parts and the bottom friction stir welding tooling of the tank are installed once, and milling (installing a milling cutter on the friction stir welding main head) and friction stir welding (installing a stirring pin on the friction stir welding main head) are realized in the same state. By ensuring that the pre-welding gap and the pre-welding misalignment amount of the welding edge are as small as possible in the same clamping state, the machining accuracy and welding accuracy are ensured. As a result, the metal crystals in the repaired welding seam area of the aluminum alloy rocket tank are uniform, the weld appearance is exquisite, the welding strength is high, the residual welding stress is small, the welding deformation is small, ensuring extremely high quality of the friction stir welding seam. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. 5 is a schematic structural view of the friction stir welding tooling for the circumferential seam of the bottom of the launch vehicle tank provided by the present invention in one embodiment; Figure 2 FIG. 6 is a schematic structural view of the friction stir welding tooling for the circumferential seam of the bottom of the launch vehicle tank provided by the present invention in another angle in one embodiment; Figure 3 FIG. 7 is a schematic structural view of the friction stir welding tooling for the circumferential seam of the bottom of the launch vehicle tank provided by the present invention in one embodiment, including an inner support part and an outer pressing part; Figure 4 FIG. 8 is a schematic structural view of the main body part of the friction stir welding tooling for the circumferential seam of the bottom of the launch vehicle tank provided by the present invention in one embodiment; Figure 5 FIG. 9 is a schematic structural view of the part where the circumferential seam of the fork-shaped ring is located provided by the present invention in one embodiment; Figure 6 FIG. 10 is a schematic structural view of the part where the die lifting mechanism is located provided by the present invention in one embodiment; Figure 7 FIG. 11 is a schematic structural view of the first part of the inner top pressing mechanism for the circumferential seam of the fork-shaped ring provided by the present invention in one embodiment; Figure 8 FIG. 12 is a schematic structural view of the second part of the inner top pressing mechanism for the circumferential seam of the fork-shaped ring provided by the present invention in one embodiment; Figure 9 FIG. 13 is a schematic structural view of the part where the circular die is located provided by the present invention in one embodiment; Figure 10 FIG. 14 is a schematic structural view of the part where the inner top pressing mechanism for the circumferential seam of the top cover is located provided by the present invention in one embodiment; Figure 11 FIG. 15 is a schematic structural view of the part where the outer pressing mechanism for the fork-shaped ring is located provided by the present invention in one embodiment; Figure 12 FIG. 16 is a schematic structural view of the part where the outer pressing mechanism for the large end of the circular ring is located provided by the present invention in one embodiment; Figure 13 FIG. 17 is a schematic structural view of the part where the outer pressing mechanism for the small end of the circular ring is located provided by the present invention in one embodiment; Figure 14 FIG. 18 is a schematic structural view of the part where the mobile gantry, the gantry top pressing mechanism and the lifting pressing mechanism are located provided by the present invention in one embodiment; Figure 15 FIG. 19 is a schematic structural view of the part where the lifting pressing mechanism is located provided by the present invention in one embodiment; Figure 16It is a schematic structural diagram of the part where the mobile gantry and the gantry tightening mechanism are provided in an embodiment of the present invention; Figure 17 It is a schematic structural diagram of a part of the mobile gantry provided in an embodiment of the present invention; Figure 18 It is a schematic structural diagram of the part where the outer pressing mechanism of the large top cover is provided in an embodiment of the present invention; Figure 19 It is a schematic structural diagram of the part where the outer pressing mechanism of the bottom lock welding is provided in an embodiment of the present invention. Detailed implementation manners

[0022] The technical solutions of the present invention will be described below with reference to the accompanying drawings through specific embodiments. It should be understood that one or more than four steps mentioned in the present invention do not exclude the existence of other methods and steps before and after the combined steps, or other methods and steps can be inserted between these clearly mentioned steps. It should also be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. Unless otherwise specified, the numbers of each method step are only for the purpose of identifying each method step, rather than limiting the arrangement order of each method or limiting the implementation scope of the present invention. The change or adjustment of their relative relationship can also be regarded as the implementable scope of the present invention under the condition of no substantial change in technical content.

[0023] There are no specific restrictions on the sources of the raw materials and instruments used in the embodiments, and they can be purchased in the market or prepared according to the conventional methods well-known to those skilled in the art.

[0024] Embodiment: The present invention provides a method for using a friction stir welding tool for the bottom circumferential seam of a launch vehicle storage tank, which is mainly used for the friction stir welding of the fork-shaped ring circumferential seam (i.e., the small end of the fork-shaped ring and the large end of the circular ring), the top cover circumferential seam (i.e., the small end of the circular ring and the large end of the top cover), and the bottom lock circumferential seam (i.e., the outer cylindrical step surface of the fork-shaped ring and the lower end of the short shell). When the present invention is used for the pre-milling and friction stir welding of the fork-shaped ring circumferential seam and the top cover circumferential seam, the workpiece is always pressed. The relevant structure ensures the accuracy of the gap amount and milling amount of the welding edges after the pre-milling of the two workpieces, which is beneficial to ensuring the high quality of the friction stir welding seam. Thereby, it ensures that the metal crystals in the repaired welding seam area of the aluminum alloy rocket storage tank are uniform, the appearance of the welding seam is beautiful, the welding strength is high, the residual welding stress is small, and the welding deformation is small, ensuring the extremely high quality of the friction stir welding seam and improving technical indicators such as the rocket carrying capacity and the reliability of the rocket system. At the same time, for the general outer pressing of the top cover and the outer pressing of the bottom lock welding, the relevant structures, the outer pressing structure and the disassembly and assembly structure are simple and convenient, greatly reducing the relevant operation time and greatly improving the operation efficiency of the outer pressing of the bottom lock welding.

[0025] As Figure 1-19As shown, in some embodiments, a friction stir welding tooling for the circumferential seam of the bottom of a launch vehicle tank is provided.

[0026] The friction stir welding tooling for the circumferential seam of the bottom of the launch vehicle tank includes: an inner support part 1, an outer pressing part 2, a fork-shaped ring workpiece 3, a circular ring workpiece 4, a top cover workpiece 5, and a short shell workpiece 6. Among them, the top cover workpiece 5 includes two specifications, a small-sized top cover workpiece and a large-sized top cover workpiece. Part of the structure of the outer pressing part 2 is installed on the ground track 7. The inner support part 1 is used to adjust the positions of the workpieces corresponding to each circumferential seam and provide an inner jacking force for at least part of the workpieces, while the outer pressing part 2 provides an outer pressure for the workpieces corresponding to each weld seam; the outer pressure can form a clamping force with the inner jacking force to clamp the workpieces.

[0027] The outer pressing part 2 includes outer pressing mechanisms corresponding to multiple circumferential seam weldings. The inner support part 2 includes a support mechanism, a position adjustment mechanism, and a circumferential seam inner jacking mechanism. Each circumferential seam is configured with a support mechanism and a position adjustment mechanism, and at least part of the circumferential seams are configured with a circumferential seam inner jacking mechanism.

[0028] Specifically, the inner support part 1 includes: a tooling base 11, a fork-shaped ring mounting seat mechanism 12, a die lifting mechanism 13, a fork-shaped ring circumferential seam inner jacking mechanism 14, a circular ring die 15, and a top cover circumferential seam inner jacking mechanism 16.

[0029] The tooling base 11 is the foundation of the inner support part 1 of the friction stir welding tooling for the circumferential seam of the bottom of the tank, and is used for the rest of the inner support part 1.

[0030] The fork-shaped ring mounting seat mechanism 12 is used for leveling and installing and fixing the fork-shaped ring workpiece 3. In some embodiments, the fork-shaped ring mounting seat mechanism 12 includes a fork-shaped ring mounting seat 121, a fork-shaped ring leveling screw 122, and a fork-shaped ring fixing screw 123; the fork-shaped ring mounting seat 121 is screwed and installed on the tooling base 11, and the upper outer side is an ellipsoid or a revolving surface of a spherical generatrix, which is close to the inner side of the fork-shaped ring workpiece 3. Then, multiple (4 or 6 pieces) fork-shaped ring leveling screws 122 installed on the fork-shaped ring mounting seat 121 are used for leveling the fork-shaped ring workpiece 3. Finally, multiple (4 or 6 pieces) fork-shaped ring fixing screws 123 installed on the fork-shaped ring mounting seat 121 are used to press the outer step surface of the fork-shaped ring workpiece 3 to realize the fixing of the fork-shaped ring workpiece 3.

[0031] The mold blank lifting mechanism 13 is installed on the tooling base 11 and is used for the overall lifting of the circular mold blank 15. In some embodiments, the mold blank lifting mechanism 13 includes a mold blank screw lift 131, a mold blank lift screw nut 132, and a mold blank lift linear guide slider 133; the lower part of the mold blank screw lift 131 is installed inside the fork-shaped ring mounting seat 121, and the mold blank lift screw nut 132 on the upper part of the mold blank screw lift 131 is fixed to the inner circular mold blank 151 in the circular mold blank 15; the mold blank lift linear guide slider 133 is installed on the fork-shaped ring mounting seat 121 and the inner circular mold blank 151 to serve as a lifting guiding mechanism; the mold blank lifting mechanism 13 uses the mold blank screw lift 131 to achieve lifting, uses the mold blank lift screw nut 132 to connect with the circular mold blank 15, and realizes lifting guidance through the mold blank lift linear guide slider 133, so as to achieve the overall lifting of the circular mold blank 15. When the mold blank screw lift 131 rises, it is used for pre-welding milling of the fork-shaped ring seam (i.e., the small end of the fork-shaped ring workpiece 3 and the large end of the circular ring workpiece 4); when the mold blank screw lift 131 falls, the fork-shaped ring mounting seat 121, the circular mold blank 15, and the fork-shaped ring welding backing plate 148 are combined into an integral mold blank for the fork-shaped ring seam part, which is used for friction stir welding of the fork-shaped ring seam (i.e., the small end of the fork-shaped ring workpiece 3 and the large end of the circular ring workpiece 4).

[0032] The inner top-tightening mechanism 14 for the fork-shaped ring circumferential seam is installed on the fork-shaped ring mounting seat 121 and is used to tightly hold the inner sides of the small end of the fork-shaped ring workpiece 3 and the large end of the circular ring workpiece 4 during the friction stir welding of the fork-shaped ring circumferential seam. In some embodiments, the inner top-tightening mechanism 14 for the fork-shaped ring circumferential seam includes a fork-shaped ring inner top-tightening motor 141, a pinion 142, a slewing support gear 143, a fork-shaped ring inner top-tightening turntable 144, a fork-shaped ring inner top-tightening rod 145, a convex fork-shaped ring inner top-tightening block 146, a concave fork-shaped ring inner top-tightening block 147, a fork-shaped ring welding backing plate 148, and a fork-shaped ring inner top linear guide slider 149; the inner top-tightening mechanism 14 for the fork-shaped ring circumferential seam adopts an inner top-tightening solution of a slewing support gear set and a connecting rod slider. The double fork-shaped ring inner top-tightening motors 141 are directly connected to the pinions 142 to drive the backlash elimination gear set of the slewing support gear 143, ensuring the top-tightening synchronism of the multiple convex fork-shaped ring inner top-tightening blocks 146 and concave fork-shaped ring inner top-tightening blocks 147 for circumferential inner top-tightening and the contour accuracy of the inner top-tightening parts. Each set of fork-shaped ring inner top-tightening motors 141 is installed inside the fork-shaped ring mounting seat 121, and the pinions 142 are installed on the upper part. The two sets of pinions 142 and the slewing support gear 143 form a gear set, and the fork-shaped ring inner top-tightening turntable 144 is installed on the upper part of the slewing support gear 143; multiple fork-shaped ring inner top-tightening rods 145 are installed circumferentially on the fork-shaped ring inner top-tightening turntable 144. The outer ends of the fork-shaped ring inner top-tightening rods 145 are installed with convex fork-shaped ring inner top-tightening blocks 146 and concave fork-shaped ring inner top-tightening blocks 147, and the outer ends of the convex fork-shaped ring inner top-tightening blocks 146 and concave fork-shaped ring inner top-tightening blocks 147 are installed with fork-shaped ring welding backing plates 148; the fork-shaped ring inner top linear guide sliders 149 are installed on the fork-shaped ring mounting seat 121 and the convex fork-shaped ring inner top-tightening blocks 146 / concave fork-shaped ring inner top-tightening blocks 147 as a circumferential top-tightening movement guiding mechanism; thus, by controlling the synchronous forward and reverse rotation of the two sets of fork-shaped ring inner top-tightening motors 141, the inner sides of the small end of the fork-shaped ring workpiece 3 and the large end of the circular ring workpiece 4 are tightly held and the top-tightening is released by the fork-shaped ring welding backing plates 148. The slewing support gear 143 rotates synchronously with the fork-shaped ring inner top-tightening turntable 144 installed thereon, driving the 16 sets of fork-shaped ring inner top-tightening rods 145 and convex fork-shaped ring inner top-tightening blocks 146 / concave fork-shaped ring inner top-tightening blocks 147 to move, and guiding the movement through the fork-shaped ring inner top linear guide sliders 149 installed at the lower parts of the convex fork-shaped ring inner top-tightening blocks 146 / concave fork-shaped ring inner top-tightening blocks 147. The 8 sets of convex fork-shaped ring inner top-tightening blocks 146 and 8 sets of concave fork-shaped ring inner top-tightening blocks 147 are installed at intervals. The front ends of the convex fork-shaped ring inner top-tightening blocks 146 / concave fork-shaped ring inner top-tightening blocks 147 are installed with fork-shaped ring welding backing plates 148. The 16 sets of fork-shaped ring welding backing plates 148 form a complete circumferential welding top-tightening ring structure to ensure the top-tightening strength of the weld seam.When the inner pressing turntable 144 of the fork-shaped ring rotates clockwise, the 16 sets of fork-shaped ring welding pads 148 move radially outward synchronously, realizing the inner pressing of the small end of the fork-shaped ring workpiece 3 and the large end of the circular ring workpiece 4, which is used for the friction stir welding of the fork-shaped ring circumferential seam; when the inner pressing turntable 144 of the fork-shaped ring rotates counterclockwise, the 16 sets of fork-shaped ring welding pads 148 move radially inward synchronously, realizing the release of the inner pressing of the small end of the fork-shaped ring workpiece 3 and the large end of the circular ring workpiece 4, which is used for the movement space of the milling cutter during the milling before the fork-shaped ring circumferential seam welding.

[0033] The circular ring die blank 15 is installed on the die blank lifting mechanism 13 and is used for the fixed installation of the circular ring workpiece 4 and the top cover workpiece 5 thereon. In some embodiments, the circular ring die blank 15 includes a circular ring inner die blank 151 and a top cover inner die blank 152; the lower circular ring inner die blank 151 and the upper top cover inner die blank 152 are screwed and centered for installation as a combination, and the outer sides of the circular ring inner die blank 151 and the top cover inner die blank 152 are ellipsoidal or spherical generatrix revolving surfaces, which are respectively close to the inner sides of the large and small ends of the circular ring workpiece 4 and the large end of the top cover workpiece 5.

[0034] The inner pressing mechanism 16 for the top cover circumferential seam is installed on the circular ring inner die blank 151 in the circular ring die blank 15 and is used for the inner pressing of the small end of the circular ring workpiece 4 and the large end of the top cover workpiece 5 during the friction stir welding of the top cover circumferential seam. In some embodiments, the inner pressing mechanism 16 for the top cover circumferential seam includes an inner pressing screw elevator 161 for the top cover circumferential seam, an inner pressing seat 162 for the top cover circumferential seam, an inner pressing block 163 for the top cover circumferential seam, a top cover welding pad 164, and a top cover welding pad guiding bushing 165; the inner pressing screw elevator 161 for the top cover circumferential seam is installed on the circular ring inner die blank 151, and the inner pressing seat 162 for the top cover circumferential seam, the inner pressing block 163 for the top cover circumferential seam, and the top cover welding pad 164 are sequentially installed on its upper part and are guided by the top cover welding pad guiding bushing 165. The top cover welding pads 164 in multiple sets (6 sets or 8 sets) of the inner pressing mechanism 16 for the top cover circumferential seam form a complete circumferential welding pressing ring structure to ensure the pressing strength of the weld seam. When multiple inner pressing screw elevators 161 for the top cover circumferential seam are synchronously lifted electrically, the top cover welding pads 164 move outward synchronously, realizing the inner pressing of the small end of the circular ring workpiece 4 and the large end of the top cover workpiece 5, which is used for the friction stir welding of the fork-shaped ring circumferential seam; when multiple inner pressing screw elevators 161 for the top cover circumferential seam synchronously fall, the top cover welding pads 164 move inward synchronously, realizing the unlocking of the inner pressing of the small end of the circular ring workpiece 4 and the large end of the top cover workpiece 5, which is used for the movement space of the milling cutter during the milling before the top cover circumferential seam welding.

[0035] The external pressing part 2 includes: a fork-shaped ring external pressing mechanism 21, a circular ring large-end external pressing mechanism 22, a circular ring small-end external pressing mechanism 23, a moving gantry 24, a gantry pressing mechanism 25, a lifting pressing mechanism 26, a large top cover external pressing mechanism 27, and a bottom-lock welding external pressing mechanism 28.

[0036] The fork-shaped ring outer pressing mechanism 21 adopts a pneumatic scheme with multiple sets of cylinders driving swing arms, and is installed on the tooling base 11, on the outer side of the inner support part 1 and the workpiece, and is used for pressing the outer side of the small end of the fork-shaped ring workpiece 3 during pre-welding milling and friction stir welding of the fork-shaped ring seam (i.e., the small end of the fork-shaped ring workpiece 3 and the large end of the circular ring workpiece 4). In some embodiments, the fork-shaped ring outer pressing mechanism 21 includes a fork-shaped ring outer pressing ring seat 211, a fork-shaped ring outer pressing cylinder seat 212, a fork-shaped ring outer pressing cylinder 213, a fork-shaped ring outer pressing cylinder mounting shaft 214, a fork-shaped ring outer pressing cylinder spherical plain bearing 215, a fork-shaped ring outer pressing cylinder spherical plain shaft 216, a fork-shaped ring outer pressing swing arm 217, a fork-shaped ring outer pressing swing arm shaft 218, a fork-shaped ring outer pressing swing arm seat 219, and a fork-shaped ring outer pressing block 2110; the fork-shaped ring outer pressing ring seat 211 is screwed and positioned on the tooling base 11, the fork-shaped ring outer pressing cylinder seat 212 is installed on the outer side of the side part of the fork-shaped ring outer pressing ring seat 211, the fork-shaped ring outer pressing cylinder 213 is hingedly installed on the fork-shaped ring outer pressing cylinder seat 212 through the fork-shaped ring outer pressing cylinder mounting shaft 214, the fork-shaped ring outer pressing cylinder spherical plain bearing 215 is installed on the upper part of the fork-shaped ring outer pressing cylinder 213, one end of the fork-shaped ring outer pressing swing arm 217 is hingedly installed on the fork-shaped ring outer pressing cylinder spherical plain bearing 215 through the fork-shaped ring outer pressing cylinder spherical plain shaft 216, the other end is screwed with the fork-shaped ring outer pressing block 2110, and the middle part is hingedly installed on the fork-shaped ring outer pressing swing arm seat 219 through the fork-shaped ring outer pressing swing arm shaft 218, and the fork-shaped ring outer pressing swing arm seat 219 is installed on the upper part of the fork-shaped ring outer pressing ring seat 211. When the fork-shaped ring outer pressing cylinder 213 is inflated, it drives multiple sets of fork-shaped ring outer pressing swing arms 217 to press the outer side of the small end of the fork-shaped ring workpiece 3; when the fork-shaped ring outer pressing cylinder 213 exhausts, it drives multiple sets of fork-shaped ring outer pressing swing arms 217 to press and contact the outer side of the small end of the fork-shaped ring workpiece 3.

[0037] The outer pressing mechanism 22 at the large end of the ring is installed in the middle of the upper side of the ring die blank 15 and is used for pressing the outer side of the large end of the ring workpiece 4 during the pre-welding milling and friction stir welding of the fork-shaped ring seam (i.e., the small end of the fork-shaped ring workpiece 3 and the large end of the ring workpiece 4). In some embodiments, the outer pressing mechanism 22 at the large end of the ring includes an outer pressing mounting shaft 221 at the large end of the ring, an outer pressing fixing nut 222 at the large end of the ring, an outer pressing connecting frame 223 at the large end of the ring, an outer pressing ring frame 224 at the large end of the ring, an outer pressing cylinder seat 225 at the large end of the ring, an outer pressing cylinder 226 at the large end of the ring, an outer pressing cylinder mounting shaft 227 at the large end of the ring, an outer pressing cylinder spherical plain bearing 228 at the large end of the ring, an outer pressing cylinder spherical plain shaft 229 at the large end of the ring, an outer pressing swing arm 2210 at the large end of the ring, an outer pressing swing arm shaft 2211 at the large end of the ring, an outer pressing block 2212 at the large end of the ring, and an outer pressing swing arm seat 2213 at the large end of the ring; the outer pressing connecting frame 223 at the large end of the ring is positioned and fitted in the central hole at the upper part of the inner ring die blank 151 through the shaft hole of the outer pressing mounting shaft 221 at the large end of the ring and is fixed by screwing with the outer pressing fixing nut 222 at the large end of the ring. The outer pressing ring frame 224 at the large end of the ring is screwed and installed at the lower part of the outer pressing connecting frame 223 at the large end of the ring. The outer pressing cylinder 226 at the large end of the ring is hinged and installed on the outer pressing ring frame 224 at the large end of the ring through the outer pressing cylinder mounting shaft 227 at the large end of the ring. The outer pressing cylinder spherical plain bearing 228 at the large end of the ring is installed on the upper part of the outer pressing cylinder 226 at the large end of the ring. One end of the outer pressing swing arm 2210 at the large end of the ring is hinged and installed on the outer pressing cylinder spherical plain bearing 228 at the large end of the ring through the outer pressing cylinder spherical plain shaft 229 at the large end of the ring, and the other end is screwed and installed with the outer pressing block 2212 at the large end of the ring. The middle part is hinged and installed on the outer pressing block 2212 at the large end of the ring through the outer pressing swing arm shaft 2211 at the large end of the ring. The outer pressing block 2212 at the large end of the ring is installed on the upper part of the outer pressing ring frame 224 at the large end of the ring, and the outer pressing swing arm seat 2213 at the large end of the ring is installed on the outer pressing ring frame 224 at the large end of the ring. When the outer pressing cylinder 226 at the large end of the ring is inflated, it drives multiple sets of outer pressing swing arms 2210 at the large end of the ring to press the outer side of the large end of the ring workpiece 4 with the outer pressing block 2212 at the large end of the ring; when the outer pressing cylinder 226 at the large end of the ring exhausts air, it drives multiple sets of outer pressing swing arms 2210 at the large end of the ring to press and contact the outer side of the large end of the ring workpiece 4 with the outer pressing block 2212 at the large end of the ring.

[0038] The outer pressing mechanism 23 at the small end of the ring is installed on the tooling base 11 and is used to press the outer side of the small end of the ring workpiece 4 during the pre-welding milling and friction stir welding of the top cover ring seam (i.e., the small end of the ring workpiece 4 and the large end of the top cover workpiece 5). In some embodiments, the outer pressing mechanism 23 at the small end of the ring includes the outer pressing mounting leg 231 at the small end of the ring, the outer pressing cylinder seat 232 at the small end of the ring, the outer pressing cylinder 233 at the small end of the ring, the outer pressing cylinder mounting shaft 234 at the small end of the ring, the outer pressing cylinder spherical plain bearing 235 at the small end of the ring, the outer pressing cylinder spherical plain shaft 236 at the small end of the ring, the outer pressing swing arm 237 at the small end of the ring, the outer pressing swing arm shaft 238 at the small end of the ring, the outer pressing block 239 at the small end of the ring, the outer pressing swing arm seat 2310 at the small end of the ring, and the outer pressing ring frame 224 at the large end of the ring (shared); the lower parts of multiple outer pressing mounting legs 231 at the small end of the ring are screwed and positioned on the tooling base 11, and the upper parts are screwed and positioned on the lower plane of the outer pressing ring frame 224 at the large end of the ring. The outer pressing cylinder seat 232 at the small end of the ring is hinged and installed on the outer pressing ring frame 224 at the large end of the ring through the outer pressing cylinder mounting shaft 234 at the small end of the ring. The outer pressing cylinder spherical plain bearing 235 at the small end of the ring is installed on the upper part of the outer pressing cylinder 233 at the small end of the ring. One end of the outer pressing swing arm 237 at the small end of the ring is hinged and installed on the outer pressing cylinder spherical plain bearing 235 at the small end of the ring through the outer pressing cylinder spherical plain shaft 236 at the small end of the ring, the other end is screwed and installed with the outer pressing block 239 at the small end of the ring, and the middle part is hinged and installed on the outer pressing block 239 at the small end of the ring through the outer pressing swing arm shaft 238 at the small end of the ring. The outer pressing block 239 at the small end of the ring is installed on the upper part of the outer pressing ring frame 224 at the large end of the ring, and multiple outer pressing swing arm seats 2310 at the small end of the ring are installed on the outer pressing ring frame 224 at the large end of the ring. When the outer pressing cylinder 233 at the small end of the ring is inflated, it drives multiple sets of outer pressing swing arms 237 at the small end of the ring to press the outer side of the small end of the ring workpiece 4; when the outer pressing cylinder 233 at the small end of the ring exhausts, it drives multiple sets of outer pressing swing arms 237 at the small end of the ring to press and contact the outer side of the small end of the ring workpiece 4. Before pressing the outer side of the small end of the ring workpiece 4, it is necessary to first remove the outer pressing mounting shaft 221 at the large end of the ring, the outer pressing fixing nut 222 at the large end of the ring, and the outer pressing connecting frame 223 at the large end of the ring.

[0039] In some embodiments, the mobile gantry 24 includes a gantry 241, driving wheels 242, a mobile gantry speed reducer 243, a mobile gantry motor 244, driven wheels 245, and a gantry tightening seat 246; the mobile gantry 24 adopts an electric moving solution (RGV) in which two sets of driving wheels 242 and two sets of driven wheels 245 are installed at the lower part of the gantry 241 on the ground track 7. The gantry 241 adopts a manufacturing solution of profile combination welding followed by machining. The electric moving adopts a transmission solution of the mobile gantry motor 244 and the mobile gantry speed reducer 243. One set of driving wheels 242 and driven wheels 245 are installed on each of the lower left and right sides of the gantry 241. The mobile gantry speed reducer 243 and the mobile gantry motor 244 are bolted together as the driving mechanism of the driving wheels 242. The two sets of driving wheels 242, the mobile gantry speed reducer 243, and the mobile gantry motor 244 enable the mobile gantry 24 to move on the ground track 7; the two sets of gantry tightening seats 246 are installed outside the left and right sides of the gantry 241 and cooperate with the gantry tightening mechanism 25 to enable the gantry tightening cylinder 252 to jack up the gantry tightening seat 246. The mobile gantry 24 is provided with two workstations such as a placement workstation and a working workstation, and is electrically controlled to automatically move between the two workstations, lock in place when reaching the working workstation, and then the gantry tightening seat 246 in the mobile gantry 24 is positioned and jacked up by the gantry tightening mechanism 25, and then used for related operations of the gantry tightening mechanism 25.

[0040] The gantry tightening mechanism 25 uses a hydraulic cylinder to jack up and tighten the mobile gantry 24; in some embodiments, the gantry tightening mechanism 25 includes a gantry tightening cylinder mounting frame 251, a gantry tightening cylinder 252, and a gantry tightening hydraulic stack 253; the gantry tightening cylinder mounting frame 251 serves as the basis of the gantry tightening mechanism 25 and is installed on the foundation under the ground. The gantry tightening cylinder 252 is installed on the gantry tightening cylinder mounting frame 251, and the corresponding gantry tightening seat 246 in the mobile gantry 24 is jacked up by controlling the 4 sets of gantry tightening cylinders 252 through the gantry tightening hydraulic stack 253, realizing the jacking and fixing of the mobile gantry 24.

[0041] The lifting and pressing mechanism 26 adopts the lifting scheme of a screw elevator and mechanical top cover pressing, and is used for milling before welding of the circumferential seam of the small-sized top cover in bottom cases of different specifications (i.e., the small end of the circular workpiece 4 and the large end of the small-sized top cover workpiece 5) and pressing the outside of the large end of the small-sized top cover workpiece 5 during friction stir welding. It is installed in the middle of the upper side of the moving gantry 24 and is used for pressing the outside of the large end of the top cover workpiece 4 during milling before welding of the circumferential seam of the top cover and friction stir welding, and pressing the outside of the short shell workpiece during friction stir welding of the bottom locking circumferential seam (i.e., the outer cylindrical step surface of the fork-shaped ring workpiece 3 and the lower end of the short shell workpiece 6). In some embodiments, the lifting and pressing mechanism 26 includes a lifting and pressing mounting frame 261, a lifting and pressing motor 262, a lifting and pressing speed reducer 263, a lifting and pressing screw elevator 264, a screw nut of the elevator 265, a lifting and pressing guide bushing 266, a lifting and pressing mounting sliding key 267, a lifting and pressing cylinder 268, a flange of the lifting and pressing cylinder 269, a rotary support of the lower interface of the lifting and pressing 2610, a flange of the lower interface of the lifting and pressing 2611, a swing arm seat for pressing the small top cover 2612, a swing arm for pressing the small top cover 2613, a swing arm shaft for pressing the small top cover 2614, an outer pressing block for the small top cover 2615, a bull's-eye bearing of the swing arm for pressing the small top cover 2616, a disc spring of the swing arm for pressing the small top cover 2617, and a tension spring of the swing arm for pressing the small top cover 2618; The lifting and pressing mounting frame 261 is installed on the upper middle part of the gantry 241 and serves as the basis of the lifting and pressing mechanism 26 for installing other components. The lifting and pressing screw elevator 264 is installed on the upper part of the lifting and pressing mounting frame 261 and adopts the transmission scheme of the lifting and pressing motor 262 and the lifting and pressing speed reducer 263. The lifting and pressing motor 262 and the lifting and pressing speed reducer 263 are fixedly connected by screwing, and the lifting and pressing speed reducer 263 is installed on the lifting and pressing screw elevator 264 on the upper part of the lifting and pressing mounting frame 261; The lifting and pressing cylinder 268 installed at the lower part of the screw of the lifting and pressing screw elevator 264 is fixedly connected by the screw nut 265 of the elevator; Between the inner cylindrical surface of the lifting and pressing mounting frame 261 and the outer cylindrical surface of the lifting and pressing cylinder 268, rotation prevention is achieved through the lifting and pressing mounting sliding key 267; Two sets of lifting and pressing guide bushings 266 are installed on the gantry 241 to serve as the lifting guide structure of the flange 269 of the lifting and pressing cylinder. The lifting and pressing cylinder 268 is installed on the screw nut 265 of the elevator and is controlled to lift by the lifting and pressing screw elevator 264; The lifting and pressing cylinder 268 is guided by the lifting and pressing guide bushing 266 and slides up and down inside the lifting and pressing mounting frame 261; And through the lifting and pressing mounting sliding key 267 installed on the side of the lifting and pressing mounting frame 261, it is used to prevent rotation when the lifting and pressing cylinder 268 lifts. The flange 269 of the lifting and pressing cylinder is installed at the lower part of the lifting and pressing cylinder 268, and the lower part is used to install the rotary support 2610 of the lower interface of the lifting and pressing and the flange 2611 of the lower interface of the lifting and pressing in sequence.The small top cover pressing swing arm seat 2612 is installed on the cylindrical surface of the outer part of the lifting pressing lower interface flange 2611. The middle part of the small top cover pressing swing arm 2613 is installed on the small top cover pressing swing arm seat 2612 through the small top cover pressing swing arm shaft 2614. The small top cover outer pressing block 2615 is installed at the front end, and parts such as the small top cover pressing swing arm ball eye bearing 2616, the small top cover pressing swing arm disc spring 2617, and the small top cover pressing swing arm tension spring 2618 are installed at the lower part of the rear end. The lower screw of the small top cover pressing swing arm ball eye bearing 2616 is screwed and installed on the lifting pressing lower interface flange through multiple small top cover pressing swing arm disc springs 2617. Inside the small top cover pressing swing arm 2613, it is connected to the lifting pressing lower interface flange 2611 through the small top cover pressing swing arm tension spring 2618. The above structure realizes the pressing of the large end of the small-sized top cover workpiece 5 by the small top cover pressing swing arm 2613 and the small top cover outer pressing block 2615 installed at the front end.

[0042] In some embodiments, the moving gantry 24, the gantry tightening mechanism 25, and the lifting pressing mechanism 26, as a general-purpose small-sized top cover outer pressing mechanism, are used for the outer pressing of small-sized top cover workpieces of the bottom of each specification box.

[0043] The outer pressing mechanism 27 of the large top cover adopts a pneumatic top cover pressing scheme and is installed on the lower interface of the lifting and pressing mechanism 26. It is used to press the outer side of the small end of the circular workpiece 4 during milling before circumferential welding of the large-sized top cover and during friction stir welding. In some embodiments, the outer pressing mechanism 27 of the large top cover includes an outer pressing ring seat 271 of the large top cover, an outer pressing cylinder seat 272 of the large top cover, an outer pressing cylinder 273 of the large top cover, an outer pressing cylinder mounting shaft 274 of the large top cover, an outer pressing cylinder spherical plain bearing 275 of the large top cover, an outer pressing cylinder spherical plain shaft 276 of the large top cover, an outer pressing swing arm 277 of the large top cover, an outer pressing swing arm shaft 278 of the large top cover, an outer pressing block 279 of the large top cover, and an outer pressing swing arm seat 2710 of the large top cover. The outer pressing ring seat 271 of the large top cover is screwed and installed on the lower interface of the lower interface flange 2611 in the lifting and pressing mechanism 26. The outer pressing cylinder seat 272 of the large top cover is installed on the outer side of the side part of the outer pressing ring seat 271 of the large top cover. The outer pressing cylinder 273 of the large top cover is hingedly installed on the outer pressing cylinder seat 272 through the outer pressing cylinder mounting shaft 274. The outer pressing cylinder spherical plain bearing 275 of the large top cover is installed on the upper part of the outer pressing cylinder 273 of the large top cover. One end of the outer pressing swing arm 277 of the large top cover is hingedly installed on the outer pressing cylinder spherical plain bearing 275 through the outer pressing cylinder spherical plain shaft 276, and the other end is screwed and installed on the outer pressing swing arm seat 2710. The middle part is hingedly installed on the outer pressing block 279 through the outer pressing swing arm shaft 278. The outer pressing block 279 of the large top cover is installed on the upper part of the outer pressing ring seat 271 of the large top cover. When the outer pressing cylinder 273 of the large top cover is inflated, it drives multiple sets of outer pressing swing arms 277 of the large top cover to press the outer side of the large end of the large-sized top cover workpiece 5. When the outer pressing cylinder 273 of the large top cover exhausts air, it drives multiple sets of outer pressing swing arms 277 of the large top cover to achieve the pressing contact of the outer pressing swing arm seat 2710 with the outer side of the large end of the large-sized top cover workpiece 5.

[0044] The outer pressing mechanism 28 for lock butt welding adopts a mechanical lock butt welding pressing scheme and is installed on the lower interface of the lifting and pressing mechanism 26. It is used to press the upper plane of the short shell workpiece 6 during friction stir welding for lock butt welding. In some embodiments, the outer pressing mechanism 28 for lock butt welding includes an outer pressing mounting seat 281 for lock butt welding, an outer pressing ring frame 282 for lock butt welding, and an outer pressing screw for lock butt welding. The outer pressing mounting seat 281 for lock butt welding is screwed and installed on the lower interface of the lower interface flange 2611 in the lifting and pressing mechanism 26. The outer pressing ring frame 282 for lock butt welding is screwed and installed on the outer pressing mounting seat 281 for lock butt welding. The lower plane of the outer pressing ring frame 282 for lock butt welding contacts the upper plane of the short shell workpiece 6. The short shell workpiece 6 and the fork-shaped ring workpiece 3 are assembled with shaft-hole fit. The upper plane of the short shell workpiece 6 is pressed through the lifting and pressing mechanism 26. At the same time, multiple pieces (8 or 12 pieces) of outer pressing screws for lock butt welding are circumferentially installed on the lower plane of the outer pressing ring frame 282 for lock butt welding and manually adjusted to firmly press the short shell workpiece 6.

[0045] In some embodiments, the movable gantry 24, the gantry clamping mechanism 25, the lifting and pressing mechanism 26, and the outer pressing mechanism 27 for the large cover are used for pneumatic external pressing of large-sized cover workpieces. The external pressing structure and disassembly structure of the pneumatic solution are simple and convenient, greatly improving the operation efficiency of the external pressing of the cover.

[0046] In some embodiments, the movable gantry 24, the gantry clamping mechanism 25, the lifting and pressing mechanism 26, and the external pressing mechanism 28 for lock-seam welding are used for external pressing during the lock-seam welding of the fork-shaped ring workpiece 3 and the short shell workpiece 6. The external pressing structure and disassembly structure are simple and convenient, greatly improving the operation efficiency of the external pressing for lock-seam welding.

[0047] During the pre-welding milling and friction stir welding of the fork-shaped ring circumferential seam (i.e., the small end of the fork-shaped ring workpiece 3 and the large end of the circular ring workpiece 4), the external pressing mechanism 21 for the fork-shaped ring and the external pressing mechanism 22 for the large end of the circular ring are always in the pressing state for the small end of the fork-shaped ring workpiece 3 and the large end of the circular ring workpiece 4 respectively. The relevant structure ensures the accuracy of the gap and milling amount of the welding edges after pre-welding milling of the two workpieces, which is beneficial to ensuring the high quality of the friction stir welding seam.

[0048] During the pre-welding milling and friction stir welding of the cover circumferential seam (i.e., the small end of the circular ring workpiece 4 and the large end of the cover workpiece 5), the external pressing mechanism 23 for the small end of the circular ring is always in the pressing state for the small end of the circular ring workpiece 4. The relevant structure ensures the accuracy of the gap and milling amount of the welding edges after pre-welding milling of the two workpieces, which is beneficial to ensuring the high quality of the friction stir welding seam.

[0049] As Figure 1 、 2 、Fig. 3 shows, in some embodiments, the fork-shaped ring mounting seat 121 is close to the inner side surface of the fork-shaped ring workpiece 3. The fork-shaped ring leveling screw 122 is used for leveling the fork-shaped ring workpiece 3, and the fork-shaped ring fixing screw 123 presses the outer stepped surface of the fork-shaped ring workpiece 3 to fix the fork-shaped ring workpiece 3.

[0050] As Figure 1 、 2 、Fig. 4 shows, in some embodiments, the die lifting mechanism 13 is used for the overall lifting of the circular ring die 15. When the die screw jack 131 rises, it is used for the pre-welding milling of the fork-shaped ring circumferential seam; when the die screw jack 131 falls, it is used for the friction stir welding of the fork-shaped ring circumferential seam.

[0051] As Figure 1 、 2, as shown in FIGS. 5, in some embodiments, when performing friction stir welding on the fork ring circumferential seam, the inner sides of the small end of the fork ring workpiece 3 and the large end of the circular ring workpiece 4 are tightly abutted. When the inner tightener turntable 144 of the fork ring rotates clockwise, the fork ring welding backing plate 148 moves radially outward synchronously, achieving the tight abutment of the inner sides of the small end of the fork ring workpiece 3 and the large end of the circular ring workpiece 4 for friction stir welding of the fork ring circumferential seam; when the inner tightener turntable 144 of the fork ring rotates counterclockwise, the fork ring welding backing plate 148 moves radially inward synchronously, achieving the tight abutment contact of the inner sides of the small end of the fork ring workpiece 3 and the large end of the circular ring workpiece 4 for the movement space of the milling cutter during milling before the fork ring circumferential seam welding.

[0052] As Figure 1 , 2 , 6, in some embodiments, the inner circular ring die 151 at the lower part of the circular ring die blank 15 and the inner top cover die 152 at the upper part are installed in a combined manner with central positioning by screwing, and the outer sides of the inner circular ring die 151 and the inner top cover die 152 are ellipsoidal or spherical generatrix revolving surfaces, which are respectively close to the inner sides of the large and small ends of the circular ring workpiece 4 and the large end of the top cover workpiece 5.

[0053] As Figure 1 , 2 , 7, in some embodiments, the inner tightener mechanism 16 for the top cover circumferential seam is used to tightly abut the inner sides of the small end of the circular ring workpiece 4 and the large end of the top cover workpiece 5 during friction stir welding of the top cover circumferential seam. When the inner tightener screw lift 161 of the top cover circumferential seam is lifted electrically, the inner sides of the small end of the circular ring workpiece 4 and the large end of the top cover workpiece 5 are tightly abutted for friction stir welding of the fork ring circumferential seam; when the inner tightener screw lift 161 of the top cover circumferential seam falls synchronously, the inner sides of the small end of the circular ring workpiece 4 and the large end of the top cover workpiece 5 are unlocked from the tight abutment for the movement space of the milling cutter during milling before the top cover circumferential seam welding.

[0054] As Figure 1 , 2 , 8, in some embodiments, the outer pressing mechanism 21 of the fork ring adopts a pneumatic scheme with multiple sets of cylinders driving swing arms to press the outer side of the small end of the fork ring workpiece 3.

[0055] As Figure 1 , 2 , 9, in some embodiments, the outer pressing mechanism 22 at the large end of the circular ring is used to press the outer side of the large end of the circular ring workpiece 4 during milling before the fork ring circumferential seam welding and friction stir welding. When the outer pressing cylinder 226 at the large end of the circular ring is inflated, it drives multiple sets of outer pressing swing arms 2210 at the large end of the circular ring to achieve the pressing of the outer pressing block 2212 at the large end of the circular ring on the outer side of the large end of the circular ring workpiece 4; when the outer pressing cylinder 226 at the large end of the circular ring exhausts air, it drives multiple sets of outer pressing swing arms 2210 at the large end of the circular ring to achieve the pressing contact of the outer pressing block 2212 at the large end of the circular ring on the outer side of the large end of the circular ring workpiece 4.

[0056] As Figure 1 , 2As shown in FIGS. 10, in some embodiments, the outer pressing mechanism 23 at the small end of the ring is used to press the outer side of the small end of the ring workpiece 4 during milling before circumferential seam welding of the top cover and friction stir welding. When the outer pressing cylinder 233 at the small end of the ring is inflated, it drives multiple sets of outer pressing swing arms 237 at the small end of the ring to press the outer side of the small end of the ring workpiece 4 with the outer pressing block 239 at the small end of the ring; when the outer pressing cylinder 233 at the small end of the ring exhausts air, it drives multiple sets of outer pressing swing arms 237 at the small end of the ring to press and contact the outer side of the small end of the ring workpiece 4 with the outer pressing block 239 at the small end of the ring.

[0057] As Figure 1 , 2 As shown in FIGS. 11 and 12, in some embodiments, the moving gantry 24 is electrically moved on the ground track 7 by installing two sets of driving wheels 242 and two sets of driven wheels 245 at the lower part of the gantry 241. The gantry 241 adopts a manufacturing scheme of combined welding of profiles followed by machining, and the electric movement adopts a transmission scheme of the moving gantry motor 244 and the moving gantry speed reducer 243. The moving gantry 24 is provided with two working positions such as a placement position and a working position, and is electrically controlled to automatically move between the two positions, lock and self-lock when reaching the working position, and then the gantry jacking mechanism 25 positions and jacks up the gantry jacking seat 246 in the moving gantry 24 for related operations of the gantry jacking mechanism 25.

[0058] As Figure 1 , 2 As shown in FIGS. 11 and 12, in some embodiments, the gantry jacking mechanism 25 adopts a scheme of jacking up the moving gantry 24 by a hydraulic cylinder. The gantry jacking cylinder 252 controls 4 sets of gantry jacking cylinders 252 to jack up the corresponding gantry jacking seats 246 in the moving gantry 24 through the gantry jacking hydraulic stack 253 to realize the jacking and fixing of the moving gantry 24.

[0059] As Figure 1 , 2 As shown in FIGS. 11 and 13, in some embodiments, the lifting and pressing mechanism 26 adopts a screw lift scheme and a mechanical top cover pressing scheme, and is used to press the outer side of the large end of the small-size top cover workpiece 5 during milling before circumferential seam welding of the small-size top cover and friction stir welding in different specifications of box bottoms. It is installed in the middle of the upper side of the moving gantry 24 and is used to press the outer side of the large end of the top cover workpiece 4 during milling before circumferential seam welding of the top cover and friction stir welding, and to press the outer side of the short shell workpiece during friction stir welding of the bottom locking circumferential seam.

[0060] As Figure 1 , 2, as shown in

[0061] As Figure 1 , 2 , 15, in some embodiments, the outer pressing mechanism 28 for bottom-lock welding is used to press the upper plane of the short shell workpiece 6 during friction stir welding for bottom-lock welding. The lower plane of the outer pressing ring frame 282 of the bottom-lock welding contacts the upper plane of the short shell workpiece 6, and the upper plane of the short shell workpiece 6 is pressed through the lifting and pressing mechanism 26. At the same time, multiple outer pressing screws for bottom-lock welding are installed circumferentially on the lower plane of the outer pressing ring frame 282 and manually adjusted to firmly press the short shell workpiece 6.

[0062] In some embodiments, the fork-shaped ring mounting seat mechanism 12 is used to install the inner side of the small end of the fork-shaped ring workpiece 3, the outer pressing mechanism 21 for the fork-shaped ring is used to press the outer side of the small end of the fork-shaped ring workpiece 3, the circular ring die 15 is used to install the inner side of the large end of the circular ring workpiece 4, and the outer pressing mechanism 22 for the large end of the circular ring is used to press the outer side of the large end of the circular ring workpiece 4.

[0063] Before milling, after the inner top pressing mechanism 14 for the fork-shaped ring circumferential seam releases the inner top pressing contact between the small end of the fork-shaped ring workpiece 3 and the large end of the circular ring workpiece 4, the die lifting mechanism 13 rises to lift the circular ring die 15 and the above structural parts. At this time, milling before the fork-shaped ring circumferential seam welding can be carried out. First, the small end of the fork-shaped ring workpiece 3 is milled, and then the large end of the circular ring workpiece 4 is milled.

[0064] Before welding, after the die lifting mechanism 13 drops, the fork-shaped ring mounting seat mechanism 12 and the circular ring die 15 are combined into a complete die. The inner top pressing mechanism 14 for the fork-shaped ring circumferential seam realizes the inner top pressing between the small end of the fork-shaped ring workpiece 3 and the large end of the circular ring workpiece 4; the outer pressing mechanism 21 for the fork-shaped ring and the outer pressing mechanism 22 for the large end of the circular ring respectively realize the outer pressing of the small end of the fork-shaped ring workpiece 3 and the large end of the circular ring workpiece 4. This ensures a smaller weld gap and misalignment before welding, and at this time, the fork-shaped ring circumferential seam welding can be carried out.

[0065] By adopting one-time installation, milling and friction stir welding of the fork-shaped ring circumferential seam are realized under the same state. By ensuring that the weld gap and misalignment before welding are as small as possible under the same clamping state, the machining accuracy of the welding edge of the fork-shaped ring circumferential seam and the welding accuracy of the weld seam are guaranteed.

[0066] In some embodiments, the inner side installation of the small end of the ring workpiece 4 is completed using the ring die 15, and the outer side of the small end of the ring workpiece 4 is clamped using the outer clamping mechanism 23 for the small end of the ring; the inner side installation of the small end of the top cover workpiece 5 is completed using the ring die 15, and the outer side of the small end of the small-sized top cover workpiece is clamped using the moving gantry 24, the gantry clamping mechanism 25, and the lifting and clamping mechanism 26, and the outer side of the small end of the large-sized top cover workpiece is clamped using the moving gantry 24, the gantry clamping mechanism 25, the lifting and clamping mechanism 26, and the outer clamping mechanism 27 for the large top cover.

[0067] Before milling, after the inner clamping mechanism 16 for the top cover ring seam releases the inner clamping contact between the small end of the ring workpiece 4 and the small end of the top cover workpiece 5, the milling of the small end of the ring workpiece 4 can be performed at this time.

[0068] Before welding, after the lifting and clamping mechanism 26 drops, the inner clamping mechanism 16 for the top cover ring seam realizes the inner clamping between the small end of the ring workpiece 4 and the small end of the top cover workpiece 5; the outer side of the small end of the small-sized top cover workpiece is clamped using the moving gantry 24, the gantry clamping mechanism 25, and the lifting and clamping mechanism 26, or the outer side of the small end of the large-sized top cover workpiece is clamped using the moving gantry 24, the gantry clamping mechanism 25, the lifting and clamping mechanism 26, and the outer clamping mechanism 27 for the large top cover. This ensures a smaller weld gap and misalignment before welding, and at this time, the welding of the top cover ring seam can be performed.

[0069] In some embodiments, the moving gantry 24, the gantry clamping mechanism 25, the lifting and clamping mechanism 26, and the outer clamping mechanism 28 for the lock bottom weld are used to complete the pre-welding clamping of the fork-shaped ring workpiece 3 and the short shell workpiece 6 during the friction stir welding of the lock bottom weld.

[0070] Before welding, after the lifting and clamping mechanism 26 drops, the outer clamping mechanism 28 for the lock bottom weld completes the clamping of the upper plane of the short shell workpiece 6. This ensures a smaller weld gap and misalignment before welding, and at this time, the welding of the lock bottom weld ring seam can be performed.

[0071] Adopting one-time installation, the milling and friction stir welding of the lock bottom weld ring seam are realized in the same state. By ensuring that the pre-welding gap and pre-welding misalignment of the welding edge are as small as possible in the same clamping state, the machining accuracy of the welding edge of the lock bottom weld ring seam and the welding accuracy of the weld are ensured.

[0072] In some embodiments, a method for using the friction stir welding tooling for the bottom ring seam of the carrier rocket tank is provided, which is applicable to the friction stir welding tooling for the bottom ring seam of the carrier rocket tank in any of the above embodiments, and includes the following steps: First, the inner support part is used to perform pre-welding milling on the fork-shaped ring seam and the top cover ring seam. During milling, it is necessary to adjust the positions of the fork-shaped ring workpiece, the ring workpiece, and the top cover workpiece to the corresponding milling positions through the inner support part; Then, friction stir welding is performed on the fork ring circumferential seam, the top cover circumferential seam, and the bottom lock circumferential seam through the inner support part and the outer pressing part. During friction stir welding, it is necessary to adjust the positions of the fork ring workpiece, the circular ring workpiece, the top cover workpiece, and the short shell workpiece to the corresponding circumferential seam welding positions through the inner support part. The inner support part also provides an inner jacking force for the workpieces corresponding to the circumferential seam welding, while the outer pressing part provides an outer pressing force for the workpieces corresponding to the circumferential seam welding. The fork ring circumferential seam is constructed by the small end of the fork ring workpiece and the large end of the circular ring workpiece. The top cover circumferential seam is constructed by the small end of the circular ring workpiece and the large end of the top cover workpiece. The bottom lock circumferential seam is constructed by the outer cylindrical step surface of the fork ring workpiece and the lower end of the short shell workpiece. The fork ring workpiece, the circular ring workpiece, the top cover workpiece, and the short shell workpiece are all arranged on the inner support part. The inner support part is used to adjust the positions of the workpieces corresponding to each circumferential seam and provide an inner jacking force for at least some of the workpieces.

[0073] When the present invention is used for friction stir welding of the circumferential seam at the bottom of the rocket tank, it has sufficient strength and stiffness. It ensures a small deformation amount, pre-welding gap, and pre-welding misalignment amount of the welding edges of the two welded parts, improving the welding quality and welding strength of the friction stir weld. The welded parts and the bottom tank friction stir welding tooling are installed once, realizing milling (installing a milling cutter on the friction stir main head) and friction stir welding (installing a stirring pin on the friction stir main head) in the same state. By ensuring that the pre-welding gap and pre-welding misalignment amount of the welding edges are as small as possible in the same clamping state, the machining accuracy and welding accuracy are guaranteed. As a result, the metal crystals in the repaired weld area of the aluminum alloy rocket storage tank are uniform, the weld appearance is exquisite, the welding strength is high, the residual welding stress is small, and the welding deformation is small, ensuring extremely high quality of the friction stir weld and improving technical indicators such as the rocket's carrying capacity and the reliability of the rocket system. Therefore, the present invention has a wide range of application prospects. The present invention adopts a universal design. For the same specification of the bottom tank, only a very small number of parts of the tooling need to be changed to be directly used with different diameters; for different specifications of the bottom tank, the tooling base 11, the moving gantry 24, the gantry tightening mechanism 25, the lifting and pressing mechanism 26, the outer pressing mechanism 27 for the large top cover, and the control and other parts are all commonly used parts. At the same time, the present invention adopts the same structure and operation control method for different specifications of the bottom tank.

[0074] The foregoing description of the specific exemplary embodiments of the present invention is for the purposes of illustration and exemplification. These descriptions are not intended to limit the present invention to the precise forms disclosed, and obviously, many changes and variations are possible in light of the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical applications, so that those skilled in the art can implement and utilize various different exemplary embodiments of the present invention, as well as various different selections and changes. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. Friction stir welding tooling for the circumferential seam of the bottom of a launch vehicle propellant tank, comprising: An inner support part and an outer pressing part connected to the inner support part, characterized in that it further includes: a fork-shaped ring workpiece, a circular ring workpiece, a top cover workpiece and a short shell workpiece. A fork-shaped ring seam is constructed by the small end of the fork-shaped ring workpiece and the large end of the circular ring workpiece, a top cover seam is constructed by the small end of the circular ring workpiece and the large end of the top cover workpiece, and a bottom locking seam is constructed by the outer cylindrical step surface of the fork-shaped ring workpiece and the lower end of the short shell workpiece; The fork-shaped ring workpiece, the circular ring workpiece, the top cover workpiece and the short shell workpiece are all arranged on the inner support part; The inner support part is used to adjust the positions of the workpieces corresponding to each seam and provide an inner jacking force for at least some of the workpieces, while the outer pressing part provides an outer pressure for the workpieces corresponding to each weld seam; the outer pressure can form a clamping force for clamping the workpieces together with the inner jacking force.

2. The friction stir welding tooling for the bottom circumferential seam of the launch vehicle tank according to claim 1, wherein: The outer pressing part includes outer pressing mechanisms corresponding to multiple seam weldings, and the inner support part includes a support mechanism, a position adjustment mechanism and a seam inner jacking mechanism. Each seam is configured with the support mechanism and the position adjustment mechanism, and at least some seams are configured with the seam inner jacking mechanism; Among them, the support mechanism is used to mount each workpiece, the position adjustment mechanism is used to adjust the position of the workpiece, and the seam inner jacking mechanism is used to provide an inner jacking force for the workpiece corresponding to the weld seam.

3. The friction stir welding tooling for the bottom ring seam of a launch vehicle propellant tank according to claim 1, characterized in that: During milling before seam welding, the fork-shaped ring workpiece, the circular ring workpiece and the top cover workpiece are all adjusted to their corresponding milling positions through the corresponding position adjustment mechanisms; and During seam welding, the fork-shaped ring workpiece, the circular ring workpiece, the top cover workpiece and the short shell workpiece are all adjusted to their corresponding seam welding positions through the corresponding position adjustment mechanisms. Each seam inner jacking mechanism provides an inner jacking force for the workpiece corresponding to the weld seam, and the outer pressing mechanism provides an outer pressure for the workpiece corresponding to the seam welding.

4. The friction stir welding tooling for the circumferential seam of the bottom of the launch vehicle propellant tank according to claim 2, characterized in that, The inner support part includes a tooling base, a fork-shaped ring mounting seat mechanism, a die carrier lifting mechanism, a fork-shaped ring seam inner jacking mechanism, a circular ring die carrier and a top cover seam inner jacking mechanism; The tooling base is used to support the rest of the inner support part; the fork-shaped ring mounting seat mechanism is used for leveling and installing and fixing the fork-shaped ring workpiece and is arranged on the tooling base; the circular ring inner die carrier is used to mount the circular ring workpiece and the top cover workpiece and is arranged on the die carrier lifting mechanism; the die carrier lifting mechanism is arranged on the tooling base and is used for the overall lifting of the circular ring die carrier; the fork-shaped ring seam inner jacking mechanism is arranged on the fork-shaped ring mounting seat and is used for inner jacking of the small end of the fork-shaped ring workpiece and the large end of the circular ring workpiece during friction stir welding of the fork-shaped ring seam; the top cover seam inner jacking mechanism is installed on the circular ring die carrier and is used for inner jacking of the small end of the circular ring workpiece and the large end of the top cover workpiece during friction stir welding of the top cover seam; Among them, the tooling base, the fork-shaped ring mounting seat mechanism and the circular ring die carrier as a whole are all components of the support mechanism, and the die carrier lifting mechanism is a component of the position adjustment mechanism.

5. The friction stir welding tooling for the circumferential seam of the bottom of the launch vehicle tank according to claim 4, wherein The inner top-tightening mechanism for the fork-shaped ring circumferential seam includes a double-fork-shaped ring inner top-tightening motor, a gear transmission mechanism, and a workpiece tightening / loosening action execution mechanism. The gear transmission mechanism includes a gear set and a fork-shaped ring inner top-tightening turntable. The workpiece tightening / loosening control action execution mechanism includes multiple sets of fork-shaped ring welding pads. All the fork-shaped ring welding pads form a complete circumferential welding top-tightening ring structure. The double-fork-shaped ring inner top-tightening motor drives the fork-shaped ring inner top-tightening turntable in the gear transmission mechanism to rotate, driving the fork-shaped ring welding pads in the workpiece tightening / loosening action execution mechanism to move radially synchronously, so as to control the tightness of the inner sides of the small end of the fork-shaped ring workpiece and the large end of the circular ring workpiece.

6. The friction stir welding tooling for the circumferential seam of the bottom of the launch vehicle tank according to claim 4, characterized in that, The number of the inner top-tightening mechanisms for the top cover circumferential seam is multiple, and each of the inner top-tightening mechanisms for the top cover circumferential seam includes: a top cover circumferential seam inner top-tightening screw jack, a top-tightening transmission mechanism, and a guiding component. The guiding component includes a top cover welding pad. All the top cover welding pads form a complete circumferential welding top-tightening ring structure. All the inner top-tightening mechanisms for the top cover circumferential seam drive the top cover welding pads in the guiding component to move synchronously through the top-tightening transmission mechanism, so as to control the tightness of the inner sides of the small end of the circular ring workpiece and the large end of the top cover workpiece.

7. The friction stir welding tooling for the circumferential seam of the bottom of the launch vehicle tank according to claim 1, wherein, The outer pressing part includes a fork-shaped ring outer pressing mechanism, a large end outer pressing mechanism for the circular ring, a small end outer pressing mechanism for the circular ring, a moving gantry, a gantry top-tightening mechanism, a lifting pressing mechanism, a large top cover outer pressing mechanism, and a bottom locking weld outer pressing mechanism.

8. The friction stir welding tooling for the circumferential seam of the bottom of the launch vehicle tank according to claim 1, wherein The top cover workpiece includes a small-sized top cover workpiece and a large-sized top cover workpiece.

9. A method for using a friction stir welding tool for the circumferential seam of the bottom of a launch vehicle propellant tank, characterized in that, Applicable to the friction stir welding tooling for the bottom circumferential seam of the launch vehicle fuel tank according to any one of claims 1 - 8, it includes the following steps: First, use the inner support part to perform pre-welding milling on the fork-shaped ring circumferential seam and the top cover circumferential seam. During milling, it is necessary to adjust the positions of the fork-shaped ring workpiece, the circular ring workpiece, and the top cover workpiece to the corresponding milling positions through the inner support part; Then, use the inner support part and the outer pressing part to perform friction stir welding on the fork-shaped ring circumferential seam, the top cover circumferential seam, and the bottom locking circumferential seam. During friction stir welding, it is necessary to adjust the positions of the fork-shaped ring workpiece, the circular ring workpiece, the top cover workpiece, and the short shell workpiece to the corresponding circumferential seam welding positions through the inner support part. The inner support part also provides an inner top force for the workpiece corresponding to the circumferential seam welding, while the outer pressing part provides an outer pressure for the workpiece corresponding to the circumferential seam welding; Finally, complete the welding of all circumferential seams.

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