A stretch forming apparatus

Abstract

The application relates to the technical field of metal plastic working, and discloses a stretch forming device which comprises a base power mechanism, a workbench, a supporting column, a pressing plate, a cylinder, a screw rod, a lower pipe opening, an auxiliary stretching mechanism and a source power stretching mechanism. When hydraulic oil enters the device and flows through the impeller set, the inherent path of the traditional hydraulic system which relies on oil compression to transmit pressure is abandoned, linear mechanical coupling of fluid driving to piston displacement is formed, action lag caused by hydraulic valve switching and pipeline pressure establishment is greatly eliminated, the piston movement track accurately follows the hydraulic instruction, the problem of slow response of the hydraulic system is solved, the auxiliary stretching mechanism can offset the piston displacement caused by the elastic deformation of the hydraulic oil, can actively compensate the fluctuation of the blank holder force caused by the pressure fluctuation of the oil circuit, maintain constant contact pressure, and can guarantee the relative uniformity and stability of the surface pressure of the blank holder ring and the plate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal plastic working, more particularly to a stretch forming device. BACKGROUND

[0002] The stretch hydraulic machine is an industrial equipment based on hydraulic transmission technology, mainly used in the fields of metal processing, rubber products, etc., and can perform processes such as correction, press packaging, packaging and stretch forming, and is called a universal hydraulic machine due to its multiple functions.

[0003] Due to the compressibility of hydraulic oil, pipeline flow resistance and control valve switching delay, the propagation speed of pressure waves in oil is limited, resulting in a significant lag between piston action instructions and execution. When fast switching of stretching and edge pressing actions is required, the hydraulic oil needs to go through multiple processes such as compression energy storage, pressure wave transmission and overcoming viscous resistance, resulting in long device startup time and uncontrolled local thinning or wrinkling defects of complex curved surface parts during the variable rate stretching stage. SUMMARY

[0004] In order to overcome the above-mentioned defects of the prior art, the present application provides a stretch forming device to solve the problems existing in the above background art.

[0005] The present application provides the following technical scheme: a stretch forming device, comprising a base power mechanism, a workbench, a support column, the top of the base power mechanism is fixedly connected with a workbench, the top of the workbench is uniformly distributed with support columns around, the outer surface of the support column is provided with a middle layer moving plate in the middle, the outer surface of the support column is provided with a top plate at the top, the top of the top plate is uniformly distributed with a fixed sleeve around, the top of the top plate is fixedly connected with a hydraulic mechanical telescopic structure, the top of the middle layer moving plate is provided with a stretching cylinder mechanism, the bottom of the middle layer moving plate is provided with a pressing plate corresponding to the position of the stretching cylinder mechanism;

[0006] The stretching cylinder mechanism comprises a cylinder fixedly arranged at the top of the middle layer moving plate, the top of the cylinder is circumferentially distributed with a screw around, the top of the cylinder is fixedly connected with a barrel, and the outer surface of the barrel is fixedly connected with a lower pipe opening on one side;

[0007] The hydraulic mechanical telescopic structure comprises an outer cylinder mechanism fixedly connected to the top of the top plate, the outer surface of the outer cylinder mechanism is provided with an upper pipe opening on the side away from the lower pipe opening, the inner side of the outer cylinder mechanism close to the top is provided with an auxiliary stretching mechanism, and the bottom of the auxiliary stretching mechanism is provided with a source power stretching mechanism;

[0008] Further, the hydraulic oil enters from the upper pipe, passes through the inside of the hydraulic mechanical telescopic structure, then passes through the inside of the stretching cylinder mechanism and finally exits from the lower pipe. The hydraulic oil can circulate completely in the inside under the action of the hydraulic pump, but the speed and response time are relatively slow. By setting the structure source power stretching mechanism and the auxiliary stretching mechanism, the power source is created by the flow of the fluid itself, so as to act on the piston in the hydraulic cylinder and help the piston move more quickly.

[0009] Further, the outer cylinder mechanism includes a large outer cylinder fixedly connected in the inside of the top plate. The inside of the top plate and the top of the middle layer moving plate are fixedly connected with a small inner cylinder. The inside of the small inner cylinder is provided with an inner layer piston. The inside of the large outer cylinder and the outside of the small inner cylinder are provided with an outer layer piston.

[0010] Further, one side of the outer surface of the large outer cylinder is fixedly connected with a connecting rod. The other side of the connecting rod is fixedly connected with the upper pipe.

[0011] Further, the auxiliary stretching mechanism includes a rotating connecting rod rotatably connected to the inside of the top of the outer cylinder mechanism. One side of the outer surface of the rotating connecting rod close to the bottom is provided with a small gear.

[0012] The source power stretching mechanism includes a circular wheel fixedly connected to the bottom of the rotating connecting rod. The outside of the circular wheel is fixedly connected with a set of impellers uniformly distributed. The bottom of the circular wheel is fixedly provided with a wire reel mechanism. One side of the wire reel mechanism is fixedly connected with a front cross rod. The other side of the wire reel mechanism is fixedly connected with a rear cross rod. The outside of the wire reel mechanism is provided with a steel wire. One side of the steel wire close to the bottom is rotatably connected with a small wire reel. The outside of the small wire reel is rotatably connected with a fixed seat one. The bottom of the fixed seat one is fixedly connected with a bottom rod.

[0013] Further, when the hydraulic oil flows through the circular wheel and contacts the set of impellers around the circular wheel, pressure and thrust are generated on the set of impellers to make the set of impellers rotate. After the set of impellers rotates, the rotating connecting rod on the set of impellers also rotates synchronously, so that the small gear and the auxiliary stretching mechanism can further move through the mutual engagement of the threads.

[0014] Further, the wire reel mechanism includes an upper fixed plate fixedly connected to the bottom of the circular wheel. The bottom of the upper fixed plate is fixedly connected with an upper wire reel. The bottom of the upper wire reel is fixedly connected with a lower wire reel. The outside of the upper wire reel and the lower wire reel is provided with a steel wire. The bottom of the lower wire reel is fixedly connected with a rear cross rod. The bottom of the rear cross rod is fixedly connected with a base disc. One side of the base disc and the same side of the upper fixed plate are fixedly connected with a front cross rod.

[0015] Further, the impeller set generates rotation, and drives the upper wire disc fixedly connected below to generate rotation, so that the steel wires arranged on the upper wire disc and the lower wire disc rotate along the structure passed by the steel wires, the winding directions of the steel wires in the upper wire disc and the lower wire disc are opposite, and the diameter of the upper wire disc is larger than that of the lower wire disc, when the impeller set moves counterclockwise, the steel wires in the upper wire disc are released, and the steel wires in the lower wire disc are wound, due to the diameter difference, the steel wires are in a downward releasing state, and the movement of the hydraulic oil to the inner layer piston is assisted; when the impeller set moves clockwise, the steel wires in the upper wire disc are wound, and the steel wires in the lower wire disc are released, under the influence of the diameter difference, the inner layer piston is pulled upward to complete the stable and efficient stretching action, mainly through the opposite winding directions of the lower wire disc and the steel wires in the lower wire disc, so that one winding and one releasing are performed when rotating, and the diameter difference between the upper wire disc and the lower wire disc is used for auxiliary work.

[0016] Further, the auxiliary stretching mechanism comprises a rotating rod rotatably connected to the top of the inner side of the outer cylinder mechanism, a small gear is arranged on the outer surface of the rotating rod and close to the bottom, a threaded rod is fixedly connected to the inside of the large outer cylinder, a built-in threaded block is arranged on the outer surface of the threaded rod and close to the two ends through threads, limit rods are rotatably connected to the two sides of the built-in threaded block, and a second fixing seat is fixedly connected to the other end of the limit rod and the top of the outer layer piston.

[0017] Further, when the source power stretching mechanism rotates counterclockwise, the hydraulic oil moves downward along the inside of the small inner cylinder, the device is ready to press and pull the material downward, and the hydraulic oil in the outside of the small inner cylinder and the inside of the large outer cylinder also flows downward to be compressed, when the rotating rod rotates to engage through the principle of the worm gear, the small gear and the threaded rod also rotate, and through the engagement of the threads again, the threaded rod moves to the side close to the rotating rod, and under the limitation of the second fixing seat and the limit rod, the outer layer piston continues to be compressed downward to help the hydraulic oil to be pressed downward more quickly, and when the hydraulic oil is pressed upward, the rotating rod rotates to engage through the principle of the worm gear, the small gear and the threaded rod also rotate, and through the engagement of the threads again, the threaded rod moves to the side away from the rotating rod, and under the limitation of the second fixing seat and the limit rod, the outer layer piston continues to be stretched upward.

[0018] Technical effects and advantages of the present application:

[0019] The present application is provided with a source power stretching mechanism, when hydraulic oil enters the device and flows through the impeller group, the fluid kinetic energy is directly converted into rotary mechanical energy, the high-speed rotation of the impeller drives the rigid connection of the steel wire transmission system, discards the inherent path of the traditional hydraulic system relying on oil compression to transmit pressure, forms the linear mechanical coupling of fluid driving to piston displacement, greatly eliminates the action lag caused by hydraulic valve switching and pipeline pressure establishment, makes the piston movement trajectory accurately follow the hydraulic instruction, solves the problem of slow response of the hydraulic system.

[0020] The present application is provided with an auxiliary stretching mechanism, the rotating impeller drives the precision pinion through the vertical rotating rod, and then drives the micro-displacement system composed of the threaded rod and the built-in threaded block, cooperates with the circumferentially arranged hard limiting rod to form a mechanical constraint frame, can offset the piston displacement caused by the elastic deformation of the hydraulic oil, can actively compensate the pressure fluctuation caused by the pressure fluctuation of the oil circuit, maintains the constant contact pressure, and can guarantee the relative uniformity and stability of the pressure of the pressure ring and the plate. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is the overall structure schematic diagram of the present application.

[0022] Figure 2 It is the structure schematic diagram of the stretching cylinder mechanism of the present application.

[0023] Figure 3 It is the structure schematic diagram of the hydraulic mechanical telescopic structure of the present application.

[0024] Figure 4 It is the cross-sectional structure schematic diagram of the hydraulic mechanical telescopic structure of the present application.

[0025] Figure 5 It is the structure schematic diagram of the source power stretching mechanism of the present application.

[0026] Figure 6 It is the structure schematic diagram of the wire reel mechanism of the present application.

[0027] Figure 7 It is the structure schematic diagram of the auxiliary stretching mechanism of the present application.

[0028] The drawings are marked as: 1, base power mechanism; 2, workbench; 3, support column; 4, middle layer moving plate; 5, top plate; 6, hydraulic mechanical telescopic structure; 61, upper pipe opening; 611, connecting rod; 62, source power stretching mechanism; 621, round wheel; 622, impeller group; 623, front cross rod; 624, rear cross rod; 625, steel wire; 626, bottom rod; 627, small wire disc; 628, fixed seat one; 629, wire disc mechanism; 6291, upper fixed plate; 6292, upper wire disc; 6293, lower wire disc; 6294, base disc; 63, auxiliary stretching mechanism; 631, rotating rod; 632, pinion; 633, threaded rod; 634, built-in threaded block; 635, limiting rod; 636, fixed seat two; 64, outer cylinder mechanism; 641, large outer cylinder; 642, outer layer piston; 643, small inner cylinder; 644, inner layer piston; 7, fixed sleeve; 8, stretching cylinder mechanism; 81, cylinder; 82, screw rod; 83, lower pipe opening; 84, cylinder body; 9, pressing plate. DETAILED DESCRIPTION

[0029] The technical solutions in the present application will be described clearly and completely below in combination with the drawings in the present application, and in addition, the forms of each structure described in the following embodiments are only examples, and the stretching forming device involved in the present application is not limited to each structure described in the following embodiments. All other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0030] Referring to Figure 1 and Figure 2 , the present application provides a stretching forming device, which comprises a base power mechanism 1, a workbench 2, a support column 3, the top of the base power mechanism 1 is fixedly connected with the workbench 2, the top of the workbench 2 is uniformly distributed with the support column 3 around, the outer surface of the middle part of the support column 3 is provided with a middle layer moving plate 4, the outer surface of the top of the support column 3 is provided with a top plate 5, the top of the top plate 5 is uniformly distributed with a fixed sleeve 7 around, the top of the top plate 5 is fixedly connected with a hydraulic mechanical telescopic structure 6, the top of the middle layer moving plate 4 is provided with a stretching cylinder mechanism 8, the bottom of the middle layer moving plate 4 is provided with a pressing plate 9 at the position corresponding to the stretching cylinder mechanism 8, the pressing plate 9 is used for fixing the edge of the metal plate and preventing wrinkles or movement from occurring during the stretching process;

[0031] The stretching cylinder mechanism 8 comprises a cylinder 81 fixedly arranged at the top of the middle layer moving plate 4, the top of the cylinder 81 is circumferentially distributed with a screw rod 82 around, the top of the cylinder 81 is fixedly connected with a cylinder body 84, the outer surface of the cylinder body 84 is fixedly connected with a lower pipe opening 83 on one side;

[0032] The hydraulic mechanical telescopic structure 6 comprises an outer cylinder mechanism 64 fixedly connected to the top of the top plate 5, an upper pipe opening 61 is arranged on the outer surface of the outer cylinder mechanism 64 away from one side of the lower pipe opening 83, an auxiliary stretching mechanism 63 is arranged on the inner side of the outer cylinder mechanism 64 close to the top, and a source power stretching mechanism 62 is arranged on the bottom of the auxiliary stretching mechanism 63.

[0033] With reference to Figure 1 and Figure 2 , hydraulic oil enters from the upper pipe opening 61, passes through the inside of the hydraulic mechanical telescopic structure 6, and finally exits from the lower pipe opening 83 through the inside of the stretching cylinder mechanism 8, wherein the hydraulic oil can be circulated smoothly and completely inside through the action of the hydraulic pump, but the speed and response time are relatively slow, and by arranging the source power stretching mechanism 62 and the auxiliary stretching mechanism 63, a power source is created by the flow of the fluid itself, so as to act on the piston inside the original hydraulic cylinder and help it move more quickly.

[0034] With reference to Figure 4 , the outer cylinder mechanism 64 comprises a large outer cylinder 641 fixedly connected to the inside of the top plate 5, a small inner cylinder 643 fixedly connected to the top of the middle layer moving plate 4 inside the top plate 5, and an outer layer piston 642 arranged on the inner side of the large outer cylinder 641 and the outer side of the small inner cylinder 643.

[0035] With reference to Figure 4 , the outer surface of one side of the large outer cylinder 641 is fixedly connected with a connecting rod 611, and the other side of the connecting rod 611 is fixedly connected with the upper pipe opening 61.

[0036] With reference to Figure 5 , the auxiliary stretching mechanism 63 comprises a rotating rod 631 rotatably connected to the top of the inner side of the outer cylinder mechanism 64, and a pinion 632 is arranged on the outer surface of one side of the rotating rod 631 close to the bottom.

[0037] The source power stretching mechanism 62 comprises a circular wheel 621 fixedly connected to the bottom of the rotating rod 631, a plurality of impeller groups 622 fixedly connected to the outer side of the circular wheel 621, a wire disc mechanism 629 fixedly arranged on the bottom of the circular wheel 621, a front cross rod 623 fixedly connected to one side of the wire disc mechanism 629, a rear cross rod 624 fixedly connected to the other side of the wire disc mechanism 629, a steel wire 625 arranged on the outer side of the wire disc mechanism 629, a small wire disc 627 rotatably connected to one side of the steel wire 625 close to the bottom, a fixed seat one 628 rotatably connected to the outer side of the small wire disc 627, and a bottom rod 626 fixedly connected to the bottom of the fixed seat one 628.

[0038] With reference to Figure 4 and Figure 5When the hydraulic oil flows through the circular wheel 621, contacts the impeller group 622 around it, it will generate pressure and thrust to make the impeller group 622 rotate, and the rotating rod 631 on the impeller group 622 will also rotate synchronously, thereby enabling the pinion 632 and the auxiliary stretching mechanism 63 to move further through the mutual engagement of the threads.

[0039] With reference to Figure 6 , the wire disc mechanism 629 includes an upper fixed plate 6291 fixedly connected to the bottom of the circular wheel 621, an upper wire disc 6292 fixedly connected to the bottom of the upper fixed plate 6291, a lower wire disc 6293 fixedly connected to the bottom of the upper wire disc 6292, and a steel wire 625 provided on the outer sides of the upper wire disc 6292 and the lower wire disc 6293. The bottom of the lower wire disc 6293 is fixedly connected to a rear cross rod 624, the bottom of the rear cross rod 624 is fixedly connected to a base disc 6294, and one side of the base disc 6294 and the same side of the upper fixed plate 6291 are fixedly connected to a front cross rod 623.

[0040] With reference to Figure 5 and Figure 6 , when the impeller group 622 rotates, it drives the upper wire disc 6292 fixedly connected below it to also rotate, thereby causing the steel wire 625 provided on the upper wire disc 6292 and the lower wire disc 6293 to rotate along the structure it passes through. The winding direction of the steel wire 625 inside the upper wire disc 6292 and the lower wire disc 6293 is opposite, and the diameter of the upper wire disc 6292 is larger than that of the lower wire disc 6293. When the impeller group 622 moves counterclockwise, the steel wire 625 inside the upper wire disc 6292 is released, and the wire inside the lower wire disc 6293 is retracted. Due to the diameter difference, the steel wire 625 is in a state of being released, and it conforms to the original movement of the hydraulic oil pressing the inner layer piston 644 downward. When the impeller group 622 moves clockwise, the steel wire 625 inside the upper wire disc 6292 is retracted, and the wire inside the lower wire disc 6293 is released. Under the influence of the diameter difference, it will assist in pulling the inner layer piston 644 upward to complete the stable and efficient stretching action. The winding direction of the steel wire 625 inside the lower wire disc 6293 is opposite to that of the upper wire disc 6292, so that one performs winding and the other performs releasing when rotating. The diameter difference between them is used to assist in the work.

[0041] With reference to Figure 7 , the auxiliary stretching mechanism 63 includes a rotating rod 631 rotatably connected to the inner top of the outer cylinder mechanism 64, a pinion 632 provided on one side of the outer surface of the rotating rod 631 close to the bottom, a threaded rod 633 fixedly connected inside the large outer cylinder 641, an internally threaded block 634 provided on the outer surface of the threaded rod 633 close to both ends through threads, a limiting rod 635 rotatably connected to both sides of the internally threaded block 634, and a fixed seat two 636 fixedly connected to the top of the outer layer piston 642 at the other end of the limiting rod 635.

[0042] Referring to Figure 7 When the source power stretching mechanism 62 rotates counterclockwise, the hydraulic oil moves downward along the inside of the small inner cylinder 643, the device is ready to press and pull the material, at the same time, the hydraulic oil in the outside of the small inner cylinder 643 and the inside of the large outer cylinder 641 will also flow downward to compress, when the rotating rod 631 rotates and engages through the principle of worm gear, the pinion 632 and the threaded rod 633 also rotate, and through the engagement of the threads, the threaded rod 633 moves towards the side close to the rotating rod 631, and under the restriction of the fixed seat two 636 and the limiting rod 635, the outer piston 642 continues to compress downward, helping the hydraulic oil to be pressed downward more quickly. Similarly, when the hydraulic oil is pressed upward, the rotating rod 631 rotates and engages through the principle of worm gear, the pinion 632 and the threaded rod 633 also rotate, and through the engagement of the threads, the threaded rod 633 moves away from the side of the rotating rod 631, and under the restriction of the fixed seat two 636 and the limiting rod 635, the outer piston 642 continues to stretch upward.

[0043] The working principle of the present application is as follows: hydraulic oil enters from the upper pipe opening 61, passes through the inside of the hydraulic mechanical telescopic structure 6, then passes through the inside of the stretching cylinder mechanism 8, and finally exits from the lower pipe opening 83. Through the driving of the process, the device completes the process of pulling the material to stretch upwardly, wherein the hydraulic oil can circulate smoothly and completely inside through the action of the hydraulic pump, but the speed and response time are relatively slow. Through the setting of the structural source power stretching mechanism 62 and the auxiliary stretching mechanism 63, the power source is created by the flow of the fluid itself, so as to act on the piston inside the original hydraulic cylinder, help it move more quickly. When the hydraulic oil flows through the circular wheel 621 and contacts the surrounding impeller set 622, pressure and thrust are generated on the impeller set 622 to make the impeller set 622 rotate. After the rotation of the impeller set 622, the rotating rod 631 on the impeller set 622 also rotates synchronously, so that the pinion 632 and the auxiliary stretching mechanism 63 can further move through the meshing of the worm and the gear. After the rotation of the impeller set 622, the upper wire disc 6292 fixedly connected below the impeller set 622 also rotates, so that the steel wire 625 arranged on the upper wire disc 6292 and the lower wire disc 6293 rotates along the structure passed by the steel wire 625. The winding inside the upper wire disc 6292 and the lower wire disc 6293 is opposite, and the diameter of the upper wire disc 6292 is larger than that of the lower wire disc 6293. When the impeller set 622 moves counterclockwise, the steel wire 625 inside the upper wire disc 6292 is released, and the wire inside the lower wire disc 6293 is retracted. Due to the diameter difference, the steel wire 625 is in a state of lowering, and conforms to the movement of the inner piston 644 pressed downwardly by the original hydraulic oil.When the impeller group 622 moves clockwise, the steel wire 625 inside the upper wire disc 6292 is retracted, and the wire inside the lower wire disc 6293 is released, which will assist in pulling the inner layer piston 644 up to complete the stable and efficient stretching action under the influence of the diameter difference. The main way is that the direction of the wire inside the lower wire disc 6293 is opposite to that of the lower wire disc 6293, so that when rotating, one is winding and the other is releasing. The diameter difference between them is used to assist the work. When the source power stretching mechanism 62 rotates counterclockwise, the hydraulic oil moves downward along the inside of the small inner cylinder 643. The device is ready to press and pull the material, and the hydraulic oil outside the small inner cylinder 643 and inside the large outer cylinder 641 will also flow downward to compress. When the rotating rod 631 rotates, the small gear 632 and the threaded rod 633 also rotate through the meshing of the worm gear, and then the threaded rod 633 moves towards the side close to the rotating rod 631 through the meshing of the threads. Under the restriction of the fixed seat two 636 and the limiting rod 635, the outer layer piston 642 continues to compress downward to help the hydraulic oil be pressed downward more quickly. Similarly, when the hydraulic oil is pressed upward, the rotating rod 631 rotates through the meshing of the worm gear to make the small gear 632 and the threaded rod 633 rotate, and then the threaded rod 633 moves away from the rotating rod 631 through the meshing of the threads. Under the restriction of the fixed seat two 636 and the limiting rod 635, the outer layer piston 642 continues to stretch upward.

[0044] Finally: the above only for the preferred embodiments of the present application, and not for limiting the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application, should be included in the protection scope of the present application.

Claims

1. A stretch forming apparatus, comprising a base power supply mechanism (1), a worktable (2), and a support column (3), characterized in that: The top of the base power supply mechanism (1) is fixedly connected to a workbench (2). Support columns (3) are evenly distributed around the top of the workbench (2). A middle moving plate (4) is provided in the middle of the outer surface of the support column (3). A top plate (5) is provided on the top of the outer surface of the support column (3). Fixing sleeves (7) are evenly distributed around the top of the top of the top plate (5). A hydraulic mechanical telescopic structure (6) is fixedly connected to the center of the top of the top plate (5). A tensioning cylinder mechanism (8) is provided on the top of the middle moving plate (4). A pressure plate (9) is provided at the bottom of the middle moving plate (4) corresponding to the position of the tensioning cylinder mechanism (8). The stretching cylinder mechanism (8) includes a cylinder (81) fixedly installed on the top of the middle moving plate (4). Screws (82) are distributed around the top of the cylinder (81) in a circumferential direction. A cylinder body (84) is fixedly connected to the top of the cylinder (81). A lower pipe opening (83) is fixedly connected to one side of the outer surface of the cylinder body (84). The hydraulic mechanical telescopic structure (6) includes an outer cylinder mechanism (64) fixedly connected to the top of the top plate (5). An upper pipe port (61) is provided on the outer surface of the outer cylinder mechanism (64) away from the lower pipe port (83). An auxiliary tensioning mechanism (63) is provided on the inner side of the outer cylinder mechanism (64) near the top. A power tensioning mechanism (62) is provided at the bottom of the auxiliary tensioning mechanism (63). The auxiliary stretching mechanism (63) includes a rotating rod (631) rotatably connected to the top of the inner side of the outer cylinder mechanism (64), and a small gear (632) is provided on the outer surface of the rotating rod (631) near the bottom. The power-driven tensioning mechanism (62) includes a wheel (621) fixedly connected to the bottom of the rotating rod (631). A uniformly distributed impeller group (622) is fixedly connected to the outer side of the wheel (621). A coil mechanism (629) is fixedly installed at the bottom of the wheel (621). A front cross rod (623) is fixedly connected to one side of the coil mechanism (629). A rear cross rod (624) is fixedly connected to the other side of the coil mechanism (629). A steel wire (625) is provided on the outer side of the coil mechanism (629). A small coil (627) is rotatably connected to the side of the steel wire (625) near the bottom. A fixed seat (628) is rotatably connected to the outer side of the small coil (627). A bottom rod (626) is fixedly connected to the bottom of the fixed seat (628).

2. The stretch forming apparatus according to claim 1, characterized in that: The outer cylinder mechanism (64) includes a large outer cylinder (641) fixedly connected inside the top plate (5), a small inner cylinder (643) fixedly connected inside the top plate (5) and the top of the middle moving plate (4), an inner piston (644) is provided inside the small inner cylinder (643), and an outer piston (642) is provided inside the large outer cylinder (641) and outside the small inner cylinder (643).

3. The stretch forming apparatus according to claim 2, characterized in that: A connecting rod (611) is fixedly connected to one side of the outer surface of the large outer cylinder (641), and an upper pipe opening (61) is fixedly connected to the other side of the connecting rod (611).

4. The stretch forming apparatus according to claim 3, characterized in that: The reel mechanism (629) includes an upper fixed plate (6291) fixedly connected to the bottom of the wheel (621). An upper reel (6292) is fixedly connected to the bottom of the upper fixed plate (6291). A lower reel (6293) is fixedly connected to the bottom of the upper reel (6292). A steel wire (625) is provided on the outer side of the upper reel (6292) and the lower reel (6293). A rear cross bar (624) is fixedly connected to the bottom of the lower reel (6293). A base disc (6294) is fixedly connected to the bottom of the rear cross bar (624). A front cross bar (623) is fixedly connected to one side of the base disc (6294) and the same side of the upper fixed plate (6291).

5. The stretch forming apparatus according to claim 2, characterized in that: The large outer cylinder (641) is internally fixedly connected to a threaded rod (633). The outer surface of the threaded rod (633) is provided with built-in threaded blocks (634) near both ends by threads. The two sides of the built-in threaded blocks (634) are rotatably connected to limit rods (635). The other end of the limit rods (635) and the top of the outer piston (642) are fixedly connected to a second fixed seat (636).

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