Large-diameter thick-wall pipe electric heating hole shrinkage equipment and hole shrinkage method thereof

Abstract

The invention relates to the technical field of non-cutting machining of metal pipes, in particular to large-diameter thick-wall pipe electric heating hole shrinkage equipment and a hole shrinkage method thereof. The large-diameter thick-wall pipe electric heating hole shrinkage equipment comprises a workbench, hole shrinkage molds, driving units, a pipe clamping device and a supporting inner core system, wherein the hole shrinkage molds and the driving units are symmetrically arranged. The supporting inner core is composed of main core rods, an auxiliary core rod and a reset piece, the installation sinking grooves of the two main core rods are arranged in a staggered mode in the circumferential direction, the auxiliary core rod is matched with the guide inclined face of the fine adjustment inserting plate through a movable sliding groove, and the auxiliary core rod is promoted to be unfolded in the radial direction to support the middle of a pipe when the diameter reducing dies move oppositely. The electric heating device is arranged to reduce deformation resistance of the pipe, the inner wall lubricating device and the outer wall lubricating device spray lubricating liquid to the inner wall and the outer wall of the pipe to reduce friction damage in the machining process, and the lubricating liquid collecting device achieves environment-friendly recovery of redundant lubricating liquid. According to the device, all-directional supporting, temperature control and precise stroke adjustment of the pipe in the diameter reducing process are achieved.

Description

Technical Field

[0001] This application relates to the technical field of non-cutting processing of metal pipes, and particularly to an electrothermal diameter-reducing device for large-diameter thick-walled pipes and its diameter-reducing method. Background Art

[0002] A diameter-reducing machine, belonging to non-cutting processing equipment, has the advantages of high production efficiency, simple process, easy operation, raw material saving, and stable quality. During the diameter-reducing operation, the end of the pipe to be diameter-reduced is placed in a specially designed diameter-reducing die. The inside of the diameter-reducing die is designed with a shape matching the outer diameter of the required finished product. The diameter-reducing machine applies an inward pressure to the end of the pipe. This pressure can be achieved through a hydraulic system or other mechanical means. As the pressure increases, the pipe is forced into the space of the diameter-reducing die that is smaller than its original diameter, thereby achieving diameter reduction.

[0003] The diameter-reducing machine is designed to uniformly reduce the diameter of the pipe. However, in actual operation, due to factors such as the friction between the die and the pipe and the flow characteristics of the material, the end of the pipe being diameter-reduced may deform or collapse due to local stress concentration. Therefore, in some diameter-reducing machines, a mandrel is inserted into the diameter-reducing end of the pipe during diameter reduction to ensure the accuracy of the inner diameter of the pipe and avoid uneven deformation of the diameter-reducing end of the pipe during the diameter reduction process.

[0004] When a double-headed diameter-reducing machine is in use, pressure is applied inward from both ends simultaneously for the diameter-reducing operation. The part of the pipe that is most likely to be affected and collapse is usually the middle part because the middle part is the farthest from the pressure sources at both ends. Even if a mandrel is inserted into the ends of the pipe, the middle part of the pipe cannot be supported enough during the diameter reduction process, resulting in deformation or collapse. Summary of the Invention

[0005] In order to provide sufficient support for the middle part of the pipe during the two-way diameter-reducing operation and reduce the defects generated by the diameter-reducing process, this application provides an electrothermal diameter-reducing device for large-diameter thick-walled pipes and its diameter-reducing method.

[0006] In a first aspect, an electrothermal diameter-reducing device for large-diameter thick-walled pipes provided by this application adopts the following technical solutions, including: A workbench; A diameter-reducing device, including two diameter-reducing dies arranged at intervals on the workbench and a driving unit for driving the diameter-reducing dies to slide. A fixing frame is connected to one side of each diameter-reducing die, and the diameter-reducing die includes a diameter-reducing channel; A pipe clamping device, arranged between the two diameter-reducing dies for clamping the pipe, and the fixing frame is located on the side of the diameter-reducing die away from the pipe clamping device; There are two support inner cores which are arranged oppositely, and the support inner cores correspond to the necking dies one by one. The support inner core includes a main mandrel, a sub-mandrel and a reset member. One end of the main mandrel passes through the necking channel corresponding to the necking die and is connected to the fixed frame; an installation sink for accommodating the sub-mandrel is provided on each main mandrel, and the installation sinks on the two main mandrels are arranged out of phase in the circumferential direction; an active sliding groove is formed on the inner side wall of the installation sink, one end of the sub-mandrel slides in the active sliding groove, and the reset member is used to drive the sub-mandrel to slide in a direction away from the fixed frame; a fine-tuning insertion plate is arranged in the active sliding groove, and one end of the fine-tuning insertion plate is provided with a guiding inclined surface; When the ends of the two support inner cores abut against each other and continue to move towards each other, the sub-mandrel gradually abuts against the adjacent guiding inclined surface, causing the two sub-mandrels to move away from each other.

[0007] By adopting the above technical solution, the necking device can make the necking die slide at both ends of the workbench, apply pressure to the end of the pipe for necking; the pipe clamping device can clamp the pipe to ensure the stable progress of the necking operation; in the support inner core, the main mandrel is connected to the fixed frame and passes through the necking channel, the sub-mandrel can slide in the installation sink and the active sliding groove, and the reset member is used to drive the sub-mandrel to slide in a direction away from the fixed frame, so that the sub-mandrel can be reset after sliding relative to the main mandrel; when driving the two necking dies to move towards each other and perform the necking operation on the pipe, the ends of the two support inner cores abut against each other, so that the support inner cores are distributed in the entire pipe section of the pipe; then the two support inner cores continue to move towards each other, the end of the pipe gradually enters the necking channel, and the sub-mandrel will also gradually abut against the adjacent guiding inclined surface; through the cooperation of the main mandrel, the sub-mandrel and the fine-tuning insertion plate, the two sub-mandrels gradually deflect and expand in the radial direction during the process of the locking die pressing on the pipe, so as to abut against the inner wall of the middle part of the pipe, which can provide sufficient support for the middle part of the pipe during the two-way necking operation, reduce the defects generated by the necking process, and improve the necking quality of the pipe.

[0008] Preferably, the sub-mandrel includes a rod body and an elastic plate fixed on the surface of the rod body, and the elastic plate is located on the side wall of the rod body away from the fine-tuning insertion plate.

[0009] By adopting the above technical solution, during the process of the two sub-mandrels moving away from each other and deflecting, the outer side wall of the sub-mandrel will gradually abut against the inner side of the active sliding groove. The setting of the elastic plate enables the outer side wall of the sub-mandrel to deform within a certain range during the process of abutting against the inner side of the active sliding groove, and it is not easy to damage the sub-mandrel and the main mandrel.

[0010] Preferably, one end of the main mandrel is movably arranged on the fixed frame, and a driving member is arranged on the fixed frame, and the driving member is used to drive the main mandrel to move in the horizontal direction.

[0011] By adopting the above technical solution, the main mandrel is movably connected to the fixing frame and driven by a driving member to move horizontally, which can further flexibly adjust the position of the supporting inner core, better adapt to different reducing requirements, and improve the accuracy of supporting the middle part of the pipe. In addition, by flexibly adjusting the position of the supporting inner core relative to the reducing die, the sliding range of the auxiliary mandrel during the reducing operation is controlled, so as to control the deflection angle range in the radial direction when the two auxiliary mandrels move away from each other, making the auxiliary mandrel deflect within a suitable range to prevent the auxiliary mandrel from excessively pressing against the pipe and damaging the pipe, and further reducing the defects generated during the reducing process.

[0012] Preferably, it further includes a pipe feeding system arranged on the workbench, and the pipe feeding system includes: A feeding box, located on one side of the pipe clamping device. The inner bottom wall of the feeding box is set as a discharging inclined plane. An outlet is provided on the side wall of the feeding box, and a plurality of receiving plates are arranged at intervals at the outlet. The receiving plates are fixed on the outer side wall of the feeding box; A receiving box, arranged below the workbench; A pipe transporting device, used to transport the pipe on the receiving plate to the pipe clamping device, and also used to transport the pipe on the pipe clamping device into the receiving box.

[0013] By adopting the above technical solution, the inner bottom wall of the feeding box being set as a discharging inclined plane facilitates the discharge of the pipe to the receiving plate. The pipe transporting device can transport the pipe on the receiving plate to the pipe clamping device, automatically complete the feeding of the pipe, and also transport the reduced-diameter pipe on the pipe clamping device into the receiving box below the workbench to achieve automatic discharging, improving the automation degree and working efficiency of the pipe reducing operation.

[0014] Preferably, the reducing die includes a die base and a die body arranged in the die base. The die base is slidably connected to the workbench, and the fixing frame is fixed on one side of the die base; An electric heating device is arranged on the side of the die base away from the fixing frame. The electric heating device includes an electric heating table and electric heating coils arranged on the electric heating table.

[0015] By adopting the above technical solution, an electric heating device is arranged on the side of the die base away from the fixing frame. The electric heating coils on the electric heating table can be used to heat the pipe, reduce the deformation resistance of the pipe, make the reducing process smoother, reduce the deformation or collapse caused by local stress concentration during the pipe reducing process, and improve the quality of the reducing process.

[0016] Preferably, it further comprises an outer wall lubricating device, the outer wall lubricating device comprises a first liquid replenishing tank, a first infusion source and a liquid sprayer, the first liquid replenishing tank is fixed on the mold base, the liquid sprayer is arranged in the mold base, and the liquid sprayer comprises a spray channel for the pipe to pass through, a plurality of first liquid spray holes are opened on the inner side wall of the spray channel, and the spray channel is arranged in line with the reduced diameter channel; The first fluid replenishment tank is connected to the liquid sprayer, and the first infusion source is arranged on the first fluid replenishment tank to drive the liquid in the first fluid replenishment tank to flow into the liquid sprayer.

[0017] By adopting the above technical scheme, the first infusion source of the outer wall lubrication device is used to drive the liquid in the first liquid replenishing tank to flow to the sprayer, and the liquid is sprayed through the first spray hole on the inner wall of the injection channel to the outer wall of the tube passing through the injection channel, thereby reducing the friction between the reduction die and the tube, avoiding the mold scratching the outer wall of the tube during the reduction process, and improving the reduction processing quality.

[0018] Preferably, it also includes an inner wall lubricating device, the inner wall lubricating device includes a second liquid replenishing tank, a second infusion source and a liquid spraying box, the second liquid replenishing tank is fixed on the fixing frame, the liquid spraying box is fixed to the end of the main core rod away from the fixing frame, and a plurality of second liquid spraying holes are opened on the outer side wall of the liquid spraying box; The second fluid replenishment tank is connected to the liquid spray box, and the second infusion source is arranged on the second fluid replenishment tank to drive the liquid in the second fluid replenishment tank to flow into the liquid spray box.

[0019] By adopting the above technical solution, the inner wall lubrication device can use the second infusion source to drive the liquid in the second fluid replenishment box to flow to the spray box during the diameter reduction operation, and spray it out through the second spray hole on the outer wall of the spray box, so that the support inner core completes the lubrication of the inner wall of the pipe while entering the interior of the pipe, greatly reducing the friction between the inner core and the pipe. After the diameter reduction is completed, the support inner core is easier to detach from the pipe.

[0020] Preferably, it also includes a lubricating liquid collecting device, which includes a liquid guiding trough body and a liquid collecting pool; a drainage hole group is opened on the workbench, and the liquid guiding trough body is fixed under the workbench in an inclined state; the drainage hole group is connected to one end of the liquid guiding trough body, and the other end extends into the liquid collecting pool.

[0021] By adopting the above technical solution, the liquid guide trough and the liquid collecting pool of the lubricating liquid collecting device cooperate with the drainage hole group on the workbench to collect excess lubricating liquid that flows to the workbench during the pipe diameter reduction process, thereby avoiding pollution and waste caused by the random flow of lubricating liquid.

[0022] Preferably, the workbench is also provided with a stroke control device, and the stroke control device is located on one side of the diameter reduction device; The stroke control device includes a stroke frame, an induction transmitter, and an induction receiver disposed on the stroke frame; A connecting bracket is fixed to one side of each die base, and the induction receiver is disposed on each connecting bracket. Two induction transmitters are spaced apart on the stroke frame; The induction transmitters and the induction receivers are in one-to-one correspondence and are used to transmit signals to the induction receivers.

[0023] By adopting the above technical solution, the induction transmitter of the stroke control device can transmit signals to the corresponding induction receivers, accurately control the moving stroke of the reducing die on the workbench, ensure that the reducing operation is carried out according to the preset distance, improve the accuracy and consistency of the reducing process, and avoid the increase of processing errors and scrap rates caused by inaccurate strokes.

[0024] On the other hand, the present application provides a reducing method. Using the above-mentioned large-diameter thick-wall pipe electrothermal reducing equipment for pipe reducing operation, it includes the following steps: S1. Pipe feeding: Transport the pipe to be reduced to the pipe clamping device and make the pipe clamping device clamp the pipe; S2. Reducing operation: Start the reducing device, drive the reducing dies at both ends of the workbench to move towards each other, make the pipe enter the reducing channel, continue to drive the reducing dies at both ends of the workbench to move towards each other, and the reducing dies apply an inward pressure to the pipe ends, so that the diameter of the pipe ends gradually decreases until the required reducing size is reached; S3. Device reset: After the reducing operation is completed, drive the reducing dies at both ends of the workbench to move away from each other, make the reducing dies move back to the initial position and disengage from the reduced pipe; S4. Pipe discharging: Remove the reduced pipe from the pipe clamping device and transport the reduced pipe away from the workbench.

[0025] By adopting the above technical solution, a series of operations such as pipe feeding, reducing, device reset, and discharging are orderly completed by using the large-diameter thick-wall pipe electrothermal reducing equipment, improving the efficiency and stability of the reducing operation. At the same time, the support inner core in the equipment can provide support for the middle part of the pipe during the reducing process, reducing processing defects such as pipe deformation or collapse caused by two-way reducing.

[0026] In summary, the present invention includes at least one of the following beneficial technical effects: 1. The support inner core in the present application moves with the reducing die to provide support for the inside of the pipe to be reduced. When the ends of the two support inner cores abut against each other and continue to move, the auxiliary mandrel moves away from each other, effectively supporting the middle part of the pipe, reducing deformation or collapse caused by stress concentration, and reducing reducing processing defects; 2. The outer wall lubrication device in the present application is installed on the die base, and while the tube is fed into the diameter reduction die, the lubricant spraying work on the outer wall of the tube is realized, which can effectively reduce the friction between the diameter reduction die and the outer wall of the tube, and avoid the diameter reduction die from scratching the tube during the diameter reduction process, so as to improve the diameter reduction quality of the tube; 3. The present application also provides an inner wall lubrication device, which lubricates the inner wall of the pipe while the supporting inner core enters the pipe, greatly reducing the friction between the supporting inner core and the inner wall of the pipe, and the supporting inner core is easier to detach from the inside of the pipe after the diameter reduction is completed; 4. The present application sets an electric heating device on the side of the mold base away from the fixed frame, and uses the electric heating coil on the electric heating table to heat the pipe before the pipe enters the mold body in the area to be reduced in diameter, thereby reducing the deformation resistance of the pipe, making the reduction process smoother, and reducing the deformation or collapse caused by local stress concentration when the pipe is reduced in diameter; 5. The inductive transmitter of the stroke control device in this application can transmit a signal to the corresponding inductive receiver, which can accurately control the moving stroke of the shrinking die on the workbench, ensure that the shrinking operation is carried out according to the preset distance, and improve the accuracy and consistency of the shrinking process; 6. The present application can collect excess lubricating liquid that flows onto the workbench during the lubrication process of the pipe through a lubricating liquid collection device so that it can be reused later, thereby improving the utilization rate of the lubricating liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the overall structure of an electric heating shrinking device for large-diameter thick-walled pipes in Example 1 of the present application; Figure 2 It is a structural schematic diagram of the material receiving box in Example 1 of the present application; Figure 3 is a schematic structural diagram of the pipe transport device in Example 1 of the present application; Figure 4 is a schematic structural diagram of the diameter reduction device in Example 1 of the present application; Figure 5 This is a front view structural schematic diagram of a large-diameter thick-walled tube electrothermal shrinking device in Example 1 of the present application; Figure 6 is a schematic structural diagram of the outer wall lubrication device in Example 1 of the present application; Figure 7 is a schematic structural diagram of the inner wall lubrication device in Example 1 of the present application; Figure 8 It is a partial cross-sectional structural schematic diagram of the inner wall lubrication device in Example 1 of the present application; Figure 9 It is a structural schematic diagram of the oil cylinder driven clamp in Example 1 of the present application; Figure 10 is a schematic structural diagram of the stroke control device in Example 1 of the present application; Figure 11 is a schematic structural diagram of the diameter reduction device in Embodiment 3 of the present application; Figure 12 is a schematic cross-sectional structural diagram of the support inner core in Embodiment 3 of the present application; Figure 13 is Figure 12 a partial enlarged structural diagram at position A in

[0028] Markings in the drawings: 1. Diameter reduction device; 11. Diameter reduction die; 111. Die base; 112. Connection bracket; 113. Slide sleeve; 114. Die body; 115. Die sleeve; 12. Driving unit; 13. Fixed frame; 131. Liquid guide slope; 1311. Liquid passing through hole; 14. Guide rod; 15. Feed screw; 16. Driving box; 161. Slide block; 162. Rotating shaft; 2. Pipe clamping device; 21. Driving oil cylinder; 22. Claw; 3. Support inner core; 31. Main core rod; 311. Installation sinking groove; 312. Movable sliding groove; 32. Sub-core rod; 321. Rod body; 3211. Guiding inclined surface; 322. Elastic plate; 33. Resetting member; 34. Fine-tuning insertion plate; 341. Guiding inclined surface; 4. Pipe feeding system; 41. Feeding box; 411. Discharge inclined surface; 412. Discharge port; 413. First box body; 414. Second box body; 415. Support column; 416. Roller; 42. Card strip; 421. Card slot; 43. Snap fastener; 431. Stopping plate; 432. Block; 44. Receiving plate; 45. Material receiving box; 451. Suspension rod; 46. Screw rod sliding table module; 461. Servo motor; 47. Lifting mechanism; 471. Lifting frame; 472. Transmission component; 4721. Worm; 4722. Gear; 4723. Rack; 48. Vertical slide rail; 49. Limit loading mechanism; 491. Power source; 492. V-shaped limiting plate; 5. Electric heating device; 51. Electric heating table; 52. Electric heating coil; 53. Connecting rod; 54. Driving motor; 55. Cooling water tank; 551. Water inlet pipe; 552. Water outlet pipe; 6. Outer wall lubrication device; 61. First liquid supplement box; 62. First liquid supply source; 621. Liquid inlet hydraulic plate; 622. Lifting source; 63. Liquid sprayer; 631. Spraying channel; 632. First liquid spraying hole; 64. Liquid supplement pipe; 65. Liquid inlet pipe; 7. Inner wall lubrication device; 71. Second liquid supplement box; 72. Second liquid supply source; 73. Liquid spraying box; 731. Second liquid spraying hole; 74. Sleeve; 75. Hose; 76. Liquid supply pipe; 8. Lubricating liquid collecting device; 81. Liquid guide trough body; 82. Liquid collecting pool; 9. Stroke control device; 91. Stroke frame; 911. Bottom frame; 912. Movable rod; 913. Scale plate; 92. Inductive emitter; 93. Inductive receiver; 10. Workbench; 101. Roller slide rail; 102. Discharge port; 103. Discharge slide rail; 104. Processing track; 105. Drain hole. Detailed implementation mode

[0029] The following will be combined with the attached Figure 1 - Attachment Figure 11 A further detailed description of the present invention will be given.

[0030] Embodiment 1

[0031] The embodiment of the present application discloses a large-diameter thick-walled pipe electrothermal sizing device. Referring to the figure, the large-diameter thick-walled pipe electrothermal sizing device includes a workbench 10, a sizing device 1, a pipe clamping device 2, a pipe feeding system 4 and a stroke control device 9 arranged on the workbench 10.

[0032] Referring to Figure 1 and Figure 2 and, the pipe feeding system 4 includes a feeding box 41, a pipe transportation device and a receiving box 45. The feeding box 41 and the sizing device 1 are arranged at intervals on the workbench 10, and a discharge port 412 is opened on the side wall of the feeding box 41 close to the sizing device 1; a discharge inclined plane 411 is arranged on the inner bottom wall of the feeding box 41. A plurality of receiving plates 44 are fixedly arranged at intervals at the discharge port 412. The receiving plates 44 are in an "L" shape, and the horizontal plate section of the receiving plate 44 is fixedly connected to the side wall of the feeding box 41.

[0033] Referring to Figure 1 and Figure 2, the feeding box 41 includes a first box body 413 and a second box body 414 which are oppositely arranged. The first box body 413 and the second box body 414 are arranged in the shape of a rectangular box body with an open top, and the opposite side walls of the first box body 413 and the second box body 414 are also open. Four support columns 415 are fixed at the bottoms of both the first box body 413 and the second box body 414, and a roller 416 is rotatably connected to the bottom of each support column 415. A roller slide rail 101 for the roller 416 to slide is provided on the workbench 10, and the roller 416 slides in the roller slide rail 101, realizing the sliding connection of the first box body 413 and the second box body 414 on the workbench 10. The distance between the first box body 413 and the second box body 414 can be changed by sliding the first box body 413 or the second box body 414 to adjust the size of the feeding box 41, so that the feeding box 41 can be applicable to pipes of different sizes. In order to keep the adjusted size of the feeding box 41 stable, clamping strips 42 are fixed on both sides of the first box body 413, and buckles 43 are fixed on both sides of the second box body 414. The clamping strips 42 and the buckles 43 are arranged in one-to-one correspondence. A plurality of card slots 421 are spaced apart along the length direction of the clamping strip 42. The buckle 43 includes a stop plate 431 which is rotatably arranged. By rotating the stop plate 431, a clamping block 432 is fixed on one side of the stop plate 431. When the clamping block 432 on one side of the stop plate 431 is clamped into a card slot 421, the relative positions of the first box body 413 and the second box body 414 can be locked.

[0034] After the pipe is loaded into the feeding box 41 from the opening at the top of the feeding box 41, the pipe slides out of the discharge port 412 along the discharge inclined plane 411 under the action of gravity and falls onto the receiving plate 44, realizing automatic discharging.

[0035] Refer to Figure 3, the pipe transportation device is located on the side of the feeding box 41 close to the necking device 1. The pipe transportation device includes a lead screw sliding table module 46, a lifting mechanism 47, and a limit loading mechanism 49. There are two lead screw sliding table modules 46 arranged at intervals on the workbench 10. The lead screws in the lead screw sliding table module 46 are perpendicular to the roller slide rail 101, and two lifting mechanisms 47 and limit loading mechanisms 49 are also correspondingly arranged for the lead screw sliding table module 46. The lifting mechanism 47 is located on the slide table in the corresponding lead screw sliding table module 46. The lifting mechanism 47 includes a lifting frame 471 and a transmission component 472. The lifting frame 471 is slidably connected to the slide table in the lead screw sliding table module 46 through a vertical slide rail 48; in this embodiment, the transmission component 472 includes a worm 4721, a gear 4722, and a rack 4723 that are sequentially engaged. The worm 4721 is slidably connected to the lifting frame 471, the gear 4722 is rotatably connected to the lifting frame 471, and the rack 4723 is fixed to one side of the vertical slide rail 48. Fix a drive source on one side of the lifting frame 471 to drive the gear 4722 to rotate, and the lifting and lowering of the lifting frame 471 can be achieved. The limit loading mechanism 49 is located at the top of the lifting frame 471. The limit loading mechanism 49 includes a power source 491 and a V-shaped limit plate 492 rotatably connected to the lifting frame 471. The power source 491 can be a rotary motor. The V-shaped limit plate 492 is driven to rotate by the rotary motor, and the V-shaped limit plate 492 can be adjusted to different use states for receiving or discharging materials. The drive source can be a stepping motor.

[0036] Refer to Figure 1 and Figure 3 , a servo motor 461 is installed at one end of the lead screw sliding table module 46. Start the servo motors 461 on the two lead screw sliding table modules 46 at the same time to drive the limit loading mechanism 49 to slide close to the feeding box 41; then use the lifting mechanism 47 to drive the limit loading mechanism 49 to move upward, so that the V-shaped limit plate 492 jacks up the pipes on the receiving plate 44. Then start the servo motors 461 on the two lead screw sliding table modules 46 again to transport the pipes to the necking device 1 for necking treatment.

[0037] Refer to Figure 1 and Figure 4 , a discharge port 102 is opened on the upper end surface of the workbench 10. The discharge port 102 is located on the side of the necking device 1 away from the feeding box 41. The pipe feeding system 4 further includes a receiving box 45. Refer to Figure 4 and Figure 5, there are two discharge slide rails 103 fixed below the workbench 10, and two rows of suspension rods 451 are fixed on the top of the material receiving box 45. The ends of the suspension rods 451 slide within the discharge slide rails 103, realizing the sliding connection of the material receiving box 45 below the workbench 10. The material receiving box 45 is arranged as a rectangular box with an open top, and the opening of the material receiving box 45 faces the discharge port 102. One end of the horizontal slide rail in the lead screw slide module 46 extends to the discharge port 102. After the pipe diameter reduction is completed, the pipe transportation device can transport the pipe to the discharge port 102; start the rotating motor to make the opening of the V-shaped limiting plate 492 face the discharge port 102, and the diameter-reduced pipe can be unloaded into the material receiving box 45.

[0038] Refer to Figure 4 and Figure 6 , the diameter reduction device 1 includes a diameter reduction die 11 and a driving unit 12. There are two diameter reduction dies 11 symmetrically arranged on the workbench 10, and two driving units 12 are also correspondingly arranged for the diameter reduction dies 11. The diameter reduction die 11 includes a die base 111 and a die body 114. A hollow die sleeve 115 is fixed inside the die base 111, and the die body 114 is fixed within the die sleeve 115. A diameter reduction channel for the pipe to enter is machined inside the die body 114. A fixed frame 13 is fixed on one side of the die base 111, and two processing tracks 104 are fixed on the workbench 10. The bottom of the die base 111 is slidably connected to the processing tracks 104. The driving unit 12 is fixed on the workbench 10. The driving unit 12 is specifically selected as a feed oil cylinder, and one end of the ejector rod of the driving unit 12 is fixedly connected to the fixed frame 13 by welding or bolts.

[0039] Refer to Figure 6 , an outer wall lubrication device 6 is provided on each die base 111. The outer wall lubrication device 6 includes a first liquid replenishing tank 61, a first liquid supply source 62, and a sprayer 63; the first liquid replenishing tank 61 is fixed at the top of the die base 111. A liquid replenishing pipe 64 is connected to the top of the first liquid replenishing tank 61, and a liquid inlet pipe 65 is fixed at the bottom. The sprayer 63 is fixed inside the die sleeve 115 and is located on one side of the die body 114. The sprayer 63 is specifically arranged as a cylindrical hollow shell, and an inner circle of the sprayer 63 is provided with a spray channel 631 for the pipe to pass through. A plurality of first liquid spray holes 632 are opened on the inner side wall at the spray channel 631. One end of the liquid inlet pipe 65 penetrates to the inner side of the die sleeve 115 and is connected to the sprayer 63. The top of the first liquid replenishing tank 61 is open. The first liquid supply source 62 includes a liquid inlet pressure plate 621 and a lifting source 622; the liquid inlet pressure plate 621 is clamped within the opening of the first liquid replenishing tank 61 and is slidably connected to the first liquid replenishing tank 61. The lifting source 622 is fixed on the side wall of the first liquid replenishing tank 61, and the lifting end of the lifting source 622 is fixedly connected to the liquid inlet pressure plate 621 through a connecting rod. By starting the lifting source 622, lubricating liquid can be replenished into the sprayer 63, facilitating the spraying of lubricating liquid on the outer side wall of the pipe before the pipe enters the die body 114. The lifting source 622 can be selected as a lifting electric cylinder.

[0040] Referring to Figure 7 and Figure 8 , an inner wall lubricating device 7 is provided on each fixing bracket 13. The inner wall lubricating device 7 includes a second liquid supply tank 71, a second liquid infusion source 72 and a liquid spraying box 73. The second liquid supply tank 71 is fixed on the fixing bracket 13. The structure of the second liquid infusion source 72 is the same as that of the first liquid infusion source 62, and the connection mode of the second liquid infusion source 72 on the second liquid supply tank 71 is the same as that of the first liquid infusion source 62 on the first liquid supply tank 61. Guide rods 14 and feed screws 15 are fixedly spaced on the fixing bracket 13, and the guide rods 14 and the feed screws 15 are arranged in parallel. There are two guide rods 14 arranged at intervals. A driving member is provided on the fixing bracket 13. The driving member is specifically set as a driving box 16. Sliders 161 are provided on both sides of the driving box 16. The sliders 161 are arranged in one-to-one correspondence with the guide rods 14 and are sleeved on the guide rods 14 and slidably connected to the guide rods 14. A motor and transmission components (not shown in the figure) are provided in the driving box 16. The feed screw 15 passes through the driving box 16 and is threadedly connected to the transmission components in the driving box 16. A rotating shaft 162 for outputting rotation is further connected to the driving box 16. A cylindrical support inner core 3 is coaxially fixed at one end of the rotating shaft 162. The outer diameter of the support inner core 3 is slightly smaller than the inner diameter of the pipe to be reduced in diameter. A sleeve 74 is sleeved outside the rotating shaft 162, and a sealing ring is fixed at the connection of the sleeve 74 and the rotating shaft 162. A liquid inlet channel is opened in the rotating shaft 162, and the liquid inlet channel is communicated with the sleeve 74. A hose 75 is communicated with the sleeve 74, and one end of the hose 75 is communicated with the second liquid supply tank 71. A liquid supply pipe 76 is fixed in the support inner core 3. One end of the liquid supply pipe 76 is communicated with the liquid inlet channel, and the other end is communicated with the liquid spraying box 73. The support inner core 3 is arranged in a cylindrical shape, and the liquid spraying box 73 is arranged in a hollow cylindrical shape. The liquid spraying box 73 is fixed at one end of the support inner core 3 away from the rotating shaft 162, and a plurality of second liquid spraying holes 731 are opened on the outer side wall of the liquid spraying box 73.

[0041] Starting the driving box 16 can drive the support inner core 3 to slide away from the fixing bracket 13, so that the support inner core 3 slides into the pipe. The support inner core 3 rotates while sliding. After the liquid spraying box 73 enters the inside of the pipe, starting the second liquid infusion source 72 can transport the lubricating liquid into the liquid spraying box 73 to spray the lubricating liquid on the inner side wall of the pipe. The design of the support inner core 3 also effectively avoids the collapse of the pipe during the diameter reduction process. The support inner core 3 cooperates with the inner wall lubricating device 7 to complete the lubrication of the inner wall of the pipe while the support inner core 3 rotates into the inside of the pipe, greatly reducing the friction between the support inner core 3 and the pipe. After the diameter reduction is completed, the support inner core 3 is more easily separated from the inside of the pipe.

[0042] In other embodiments, the support inner core 3 can also be directly fixed on the fixing bracket 13.

[0043] Referring toFigure 6 On one side of the die holder 111 away from the fixing frame 13, there is an electric heating device 5. The electric heating device 5 includes an electric heating table 51 and an electric heating coil 52. The inner diameter of the electric heating coil 52 is larger than the outer diameter of the pipe to be reduced in diameter so that the pipe can pass through. A connecting rod 53 is rotatably connected to the electric heating table 51. The electric heating coil 52 is fixed to the connecting rod 53 and is electrically connected to the electric heating table 51. A driving motor 54 is installed inside the electric heating table 51. Starting the driving motor 54 can drive the connecting rod 53 to rotate, making the electric heating coil 52 approach or move away from the die sleeve 115. The electric heating table 51 can be made of ceramic or plastic, having good insulation and heat resistance. The electric heating coil 52 can be a copper coil, which can quickly generate heat after being powered on, preheat the pipe, reduce the hardness of the pipe, and facilitate the diameter reduction operation.

[0044] Refer to Figure 4 On one side of the electric heating table 51, there is also a cooling water tank 55 fixed. An inlet pipe 551 and an outlet pipe 552 are connected to the cooling water tank 55. The electric heating coil 52 is hollow. One end of the inlet pipe 551 penetrates into the connecting rod 53 and is communicated with one end of the electric heating coil 52. One end of the outlet pipe 552 also penetrates into the connecting rod 53 and is communicated with the other end of the electric heating coil 52. A water pump is installed inside the cooling water tank 55. The water outlet end of the water pump is connected to the inlet pipe 551, and can transport the water in the cooling water tank 55 into the inlet pipe 551. After the electric heating coil 52 is used up, start the water pump, transport the cooling water in the cooling water tank 55 along the inlet pipe 551 into the electric heating coil 52, and then drain it into the cooling water tank 55 from the outlet pipe 552 to realize the circulation of the cooling water.

[0045] Refer to Figure 1 and Figure 4 On the workbench 10, there is also a lubricating fluid collecting device 8. Drainage hole groups are provided on the workbench 10. The drainage hole groups are located between two processing tracks 104 on the workbench 10. The drainage hole groups include a plurality of drainage holes 105, and the drainage holes 105 are provided in circular and square shapes. Refer to Figure 4 and Figure 8 In order to facilitate the excess lubricating fluid flowing onto the fixing frame 13 to flow into the drainage holes 105, a liquid guiding slope 131 is also machined on the fixing frame 13, and a liquid passing through hole 1311 is provided on the liquid guiding slope 131. Refer to Figure 1 The lubricating fluid collecting device 8 includes a liquid guiding trough body 81 and a liquid collecting pool 82. One end of the liquid guiding trough body 81 is fixed to the bottom of the workbench 10, and two liquid guiding trough bodies 81 are spaced apart under the workbench 10. The projection of the drainage hole 105 in the vertical direction is located on the inner bottom wall of the liquid guiding trough body 81, so that the lubricating fluid can flow into the liquid guiding trough body 81 along the drainage hole 105. The liquid collecting pool 82 is located below the liquid guiding trough body 81. One end of the liquid guiding trough body 81 slopes downward away from the workbench 10 and extends into the liquid collecting pool 82.

[0046] Refer to Figure 1 andFigure 9 The pipe clamping device 2 is arranged between two necking dies 11. The pipe clamping device 2 includes two oil cylinder-driven clamps arranged at intervals. The oil cylinder-driven clamp includes a driving oil cylinder 21 and an openable and closable jaw 22. The driving oil cylinder 21 is located at the bottom of the workbench 10 and is fixedly connected to the workbench 10. The jaw 22 is located above the workbench 10. By starting the two driving oil cylinders 21 simultaneously, the opening and closing of the jaw 22 can be realized, so that the jaw 22 can clamp or loosen the pipe. When necking the pipe, the pipe needs to be transported between the two necking dies 11. After clamping the pipe by using the pipe clamping device 2, the drive box 16 and the drive unit 12 can be started.

[0047] Refer to Figure 1 and Figure 10 As shown in FIGS. and, a stroke control device 9 is further arranged on the workbench 10. The stroke control device 9 is located on the side of the pipe clamping device 2 away from the feeding box 41. The stroke control device 9 includes a stroke frame 91, an induction emitter 92 and an induction receiver 93. The stroke frame 91 includes a base frame 911, a movable rod 912 fixed on the base frame 911 and a strip-shaped scale plate 913. Scale lines are engraved on the scale plate 913 along its length direction. A connecting bracket 112 is fixed on one side of each die base 111. One end of the connecting bracket 112 is fixed with a sliding sleeve 113. The sliding sleeve 113 is sleeved on the movable rod 912 and is slidably connected with the sliding rod. Induction receivers 93 are fixed at the bottoms of the two connecting brackets 112. Two induction emitters 92 are slidably connected to the bottom of the scale plate 913. There is a certain friction between the induction emitter 92 and the scale plate 913, so that the position of the induction emitter 92 after sliding is relatively stable. The induction receivers 93 and the induction emitters 92 are arranged in one-to-one correspondence. The induction receiver 93 is electrically connected to the drive unit 12 corresponding to the connected die base 111. The induction emitter 92 can be adjusted to the position corresponding to the scale line on the scale bar according to the distance to be necked. During the necking process, the die base 111 drives the induction receiver 93 to move. By receiving the signal emitted by the induction emitter 92 through the induction receiver 93, the moving distance of the necking die 11 can be confirmed to accurately control the necking distance of the pipe. The induction emitter 92 can be selected from an optoelectronic sensor or an ultrasonic sensor, etc.

[0048] In the embodiment of the present application, the implementation principle of a large-diameter thick-wall pipe electrothermal sizing device is as follows: During operation, first adjust the width of the feeding box 41 and the initial distance between the two sizing dies 11 according to the pipe size to facilitate the smooth placement of the pipe. Slide the first box body 413 and the second box body 414 and lock the distance between the first box body 413 and the second box body 414 through the buckle 43 and the card slot 421, then multiple pipes can be stacked in the feeding box 41. The pipes slide along the discharge inclined plane 411 to the receiving plate 44. The two screw slide table modules 46 synchronously drive the limit loading mechanism 49 to move towards the feeding box 41, and the V-shaped limit plate 492 is lifted by the lifting mechanism 47 to lift the pipes and transport the pipes to the sizing station; then the pipe is clamped by the oil cylinder-driven clamp to position the pipe.

[0049] Subsequently, start the two driving units 12 simultaneously, make the two sizing dies 11 move towards each other, and apply pressure synchronously to form the pipe through the sizing channel. The electric heating coil 52 in the electric heating device 5 rotates to the front of the die base 111 to heat the pipe; when the pipe enters the die base 111, start the first liquid supply source 62, the second liquid supply source 72 and the driving part, and the sprayer 63 forms an annular lubricating coating through the first spray holes 632. At the same time, the driving box 16 drives the rotating support inner core 3 to insert the spray liquid box 73 into the pipe, and spray the inner wall of the pipe through the second spray holes 731; the driving unit 12 drives the two die bases 111 to move towards each other along the processing track 104, and cooperates with the sensor of the stroke control device 9 to accurately control the sliding distance of the two sizing dies 11. After the pipe processing is completed, the pipe clamping device 2 releases the workpiece, and the screw slide table module 46 transports the pipe in the reverse direction to the discharge port 102, and rotates the V-shaped limit plate 492 to unload the finished product into the receiving box 45. The excess lubricating liquid on the workbench 10 flows into the liquid collecting pool 82 through the liquid guiding slope 131 and the drain hole 105; finally, the driving unit 12 drives the two sizing dies 11 to reset, and the pipe transportation device returns to the initial position to complete the cycle. The whole process realizes full-automatic feeding, positioning, lubrication, heating and sizing, and unloading, ensuring that the pipe is uniformly stressed and the surface quality is controllable.

[0050] Embodiment 2

[0051] This embodiment discloses a sizing method for a large-diameter thick-wall pipe electrothermal sizing device 1. The large-diameter thick-wall pipe electrothermal sizing device 1 in Embodiment 1 is used to size the pipe. The specific steps are as follows: S1. Pipe feeding: Transport the pipe to be sized to the pipe clamping device 2 and make the pipe clamping device 2 clamp the pipe.

[0052] S11. According to the length of the pipe to be reduced in diameter, slide the first box body 413 and the second box body 414 to adjust the size of the feeding box 41, and then fix the size of the feeding box 41 by the cooperation of the clamping strip 42 and the buckle 43. Arrange multiple pipes to be reduced in diameter in the feeding box 41. After the pipes are discharged from the discharge port 412, they are supported by the L-shaped material receiving plate 44.

[0053] S12. The pipe transportation device moves under the action of the lead screw sliding table module 46 to the lower part of the material receiving plate 44. The V-shaped limiting plate 492 on the lifting frame 471 lifts the pipe to be reduced in diameter, and then under the combined action of the lead screw sliding table module 46, the lifting mechanism 47 and the limiting material loading mechanism 49, the pipe is sent to the clamping jaws 22 of the pipe clamping device 2.

[0054] S13. Start the drive oil cylinders 21 in each pipe clamping device 2 to make the clamping jaws 22 close and clamp the pipes. Ensure that the pipes will not displace during the diameter reduction process.

[0055] S2. Diameter reduction operation: Start the diameter reduction device 1, drive the diameter reduction dies 11 at both ends of the workbench 10 to move towards each other, make the pipe enter the diameter reduction channel, and continue to drive the diameter reduction dies 11 at both ends of the workbench 10 to move towards each other. The diameter reduction dies 11 apply an inward pressure to the end of the pipe, so that the outer diameter of the pipe end gradually decreases until the required diameter reduction size is reached.

[0056] S21. The drive unit 12 drives the support inner core 3, the outer wall lubrication device 6, the inner wall lubrication device 7, the diameter reduction die 11, the electric heating device 5, etc. to move to a position close to the port of the pipe to be reduced in diameter. At this time, start the drive box 16 to make the support inner core 3 slowly rotate and pass through the die body 114 along the diameter reduction channel.

[0057] S22. The drive unit 12 continues to work to drive the two diameter reduction dies 11 to move towards each other. While the diameter reduction dies 11 are moving, the electric heating device 5 is powered on, and the electric heating coil 52 preheats the pipe to be reduced in diameter.

[0058] S23. The diameter reduction die 11 continues to feed, so that the heated pipe enters the diameter reduction die 11. The first liquid supply source 62 acts to spray the lubricating liquid in the first liquid supply tank 61 from the liquid sprayer 63 through the liquid inlet pipe 65 to achieve the lubrication of the outer wall of the pipe.

[0059] S24. While the diameter reduction die 11 is feeding, the liquid spraying box 73 connected to one end of the support inner core 3 enters the interior of the pipe to be reduced in diameter; start the second liquid supply source 72, send the lubricating liquid in the second liquid supply tank 71 to the sleeve 74 through the hose 75, and then send it to the liquid spraying box 73, and then evenly spray the lubricating liquid onto the inner wall of the pipe through the second liquid spraying holes 731 on the liquid spraying box 73.

[0060] S25. The driving unit 12 continues to move, and the two reducing dies 11 move towards each other, causing the pipe to gradually enter the die body 114 for pipe reducing operation.

[0061] S26. During the reducing operation, the induction receiver 93 moves together with the die holder 111 until the induction receiver 93 moves to the position of the induction transmitter 92 and receives the signal emitted by the induction transmitter 92, indicating that the required reducing size has been reached and the reducing operation is completed.

[0062] S3. Device reset. After the reducing operation is completed, the reducing dies 11 at both ends of the driving workbench 10 move away from each other, causing the reducing dies 11 to move back to the initial position and separate from the reduced pipe. The driving unit 12 on the workbench 10 contracts, driving the support inner core 3, the outer wall lubrication device 6, the inner wall lubrication device 7, the reducing dies 11, the electric heating device 5, and the induction receiver 93 to retreat from the pipe.

[0063] S4. Pipe unloading. The reduced pipe is removed from the pipe clamping device 2 and transported away from the workbench 10.

[0064] S41. The jaws 22 in each oil cylinder-driven clamp are loosened, and the reduced pipe is lifted by the V-shaped limit plate 492 on the lifting frame 471. Then, with the cooperation of the lead screw slide module 46, the lifting mechanism 47, and the limit loading mechanism 49, the reduced pipe is sent to the unloading port 102. The rotary motor is started to make the V-shaped limit plate 492 rotate towards the direction of the unloading port 102, and the pipe is dumped from the unloading port 102 of the workbench 10 into the receiving box 45 to complete the unloading.

[0065] S42. During the reducing operation, there will be excess overflow of the lubricating fluid. The lubricating fluid on the fixing frame 13 flows into the middle of the two processing tracks 104 on the workbench 10 through the liquid passing through holes 1311 on the liquid guiding slope 131, then flows into the liquid guiding groove body 81 through the liquid drainage hole group on the processing table, and finally flows towards the liquid collecting pool 82 along the liquid guiding groove body 81.

[0066] Embodiment 3

[0067] The embodiment of the present application discloses a large-diameter thick-wall pipe electrothermal reducing device. The difference between this embodiment and Embodiment 1 is as follows: Refer to Figure 11, the outer diameter of the support inner core 3 is slightly smaller than the inner diameter of the pipe to be reduced in diameter. In this embodiment, one end of each support inner core 3 extends away from the drive box 16 and passes through the die base 111. Extend the lengths of the two processing tracks 104 and replace the feed cylinder with a longer telescopic stroke to increase the sliding stroke of the diameter reduction die 11. In this embodiment, the support inner core 3 includes a main core rod 31, a sub-core rod 32, and a reset member 33. One end of the main core rod 31 is fixed to the rotating shaft 162, and an installation sink 311 is formed at the end of the main core rod 31 away from the rotating shaft 162. The installation sinks 311 on the two main core rods 31 on the workbench 10 are arranged in a circumferential offset. In this embodiment, the sub-core rod 32 is arranged in a semi-cylindrical shape; correspondingly, the installation sinks 311 on the two main core rods 31 are offset by 180° circumferentially. When the sub-core rod 32 is arranged in other shapes, the circumferential offset angle of the installation sinks 311 on the two main core rods 31 can be designed adaptively according to the shape of the sub-core rod 32.

[0068] Refer to Figure 11 and Figure 12 , an activity chute 312 is formed on the inner side wall of the installation sink 311, and one end of the sub-core rod 32 slides in the activity chute 312. The sub-core rod 32 includes a rod body 321 and an arc-shaped elastic plate 322. A receiving sink is formed on the side wall of the rod body 321 away from the fine-tuning insertion plate 34, and the elastic plate 322 is fixed in the receiving sink. Both the rod body 321 and the main core rod 31 can be made of metal materials, and the elastic plate 322 can be made of elastic materials such as rubber or spring steel plate. The reset member 33 is located in the activity chute 312. In this embodiment, the reset member 33 is a reset spring, which is fixed between the inner side wall of the activity chute 312 and the sub-core rod 32. When the sub-core rod 32 is externally squeezed, the spring is compressed. After the external force disappears, the spring returns to its original state and pushes the sub-core rod 32 back to its original position.

[0069] Refer to Figure 12 and Figure 13 , a fine-tuning insertion plate 34 is fixed in the activity chute 312, and a guiding inclined surface 341 is processed at one end of the fine-tuning insertion plate 34 close to the sub-core rod 32. A guiding inclined surface 3211 is processed at one end of the sub-core rod 32 close to the reset member 33, and the included angle range between the inclination direction of the guiding inclined surface 3211 and the guiding inclined surface 341 is 0 - 90°. In this embodiment, it is specifically 15°. The fine-tuning insertion plate 34 can be made of lightweight materials such as plastic or aluminum alloy.

[0070] In this embodiment, the liquid spraying box 73 is arranged as a semi-cylindrical box body, and the liquid spraying box 73 is fixedly embedded at one end of the main core rod 31, and the liquid supply pipe 76 is also only distributed in the main core rod 31.

[0071] During the pipe diameter reduction operation, start the two drive units 12 and the drive box 16. After the ends of the two support inner cores 3 abut against each other inside the pipe, the support inner cores 3 are distributed within the entire pipe section of the pipe. Before starting the drive box 16, it is necessary to adjust the placement angles of the two support inner cores 3 so that the sub-core rods 32 inside one support inner core 3 correspond to the installation sinking grooves 311 inside the other support inner core 3; this facilitates controlling that after the ends of the two support inner cores 3 abut against each other inside the pipe and the drive box 16 is shut down, the sub-core rods 32 inside the support inner cores 3 are opposite to the installation sinking grooves 311 inside the other support inner core 3. The two drive units 12 continue to drive the support inner cores 3 to move towards each other, causing the pipe ends to gradually enter the diameter reduction channel of the die body 114. At this time, the sub-core rods 32 slide in the direction close to the fine-tuning insertion plate 34 under the pressing of the main core rods 31 opposite to themselves, and each sub-core rod 32 gradually abuts against the guiding inclined surfaces 341 of the adjacent fine-tuning insertion plates 34 during sliding. Through the mutual cooperation of the main core rods 31, sub-core rods 32, and fine-tuning insertion plates 34, the two sub-core rods 32 gradually deflect radially and expand during the process of the locking die pressing on the pipe, so as to tightly press against the inner pipe wall in the middle of the pipe, enabling the ends of the sub-core rods 32 to provide more effective support for the middle part of the pipe.

[0072] By controlling the drive box 16, the length of the support inner core 3 extending out of the die base 111 can be precisely adjusted. On the one hand, when controlling the drive unit 12 to drive the diameter reduction die 11 to slide and the support inner core 3 to move towards the pipe, before the ends of the two support inner cores 3 abut against each other, the pipe ends will not enter the contraction channel of the die body 114 (not shown in the figure) for diameter reduction; after the ends of the two support inner cores 3 abut against each other, the pipe can enter the contraction channel of the die body 114 only with the continuous feeding of the support inner core 3, so as to ensure the effective support of the support inner core 3 for the middle part of the pipe during the diameter reduction operation. On the other hand, when processing pipes of different lengths, adjusting the length of the support inner core 3 extending out of the die base 111 can also control the distance that needs to be continuously fed after the ends of the two support inner cores 3 abut against each other inside the pipe to complete the diameter reduction operation of the pipe, so as to control the sliding range of the sub-core rods 32; thereby indirectly controlling the deflection angle range in the radial direction when the two sub-core rods 32 move away from each other, enabling the sub-core rods 32 to deflect within a suitable range to prevent the sub-core rods 32 from causing excessive pressing on the inner wall of the pipe and damaging the pipe, and further reducing the defects generated during the diameter reduction processing.

[0073] The embodiments of this specific implementation manner are all preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. An electrothermal necking-down device for large-diameter thick-walled pipes, characterized in that, Comprising: A workbench (10); A diameter-reducing device (1), including two diameter-reducing dies (11) spaced apart on the workbench (10), and a driving unit (12) for driving the sliding of the diameter-reducing dies (11). A fixing frame (13) is connected to one side of each diameter-reducing die (11), and the diameter-reducing die (11) includes a diameter-reducing channel; A pipe clamping device (2), arranged between the two diameter-reducing dies (11) for clamping a pipe. The fixing frame (13) is located on the side of the diameter-reducing die (11) away from the pipe clamping device (2); Two support inner cores (3) are oppositely arranged, and the support inner cores (3) correspond to the diameter-reducing dies (11) one by one. The support inner core (3) includes a main core rod (31), a sub-core rod (32), and a reset member (33). One end of the main core rod (31) passes through the diameter-reducing channel of the corresponding diameter-reducing die (11) and is connected to the fixing frame (13); An installation sink (311) for accommodating the sub-core rod (32) is provided on each main core rod (31), and the installation sinks (311) on the two main core rods (31) are circumferentially offset; An activity chute (312) is opened on the inner side wall of the installation sink (311), one end of the sub-core rod (32) slides in the activity chute (312), and the reset member (33) is used to drive the sub-core rod (32) to slide in a direction away from the fixing frame (13); A fine-tuning insertion plate (34) is arranged in the activity chute (312), and a guiding inclined surface (341) is arranged at one end of the fine-tuning insertion plate (34); When the ends of the two support inner cores (3) abut against each other and continue to move towards each other, the sub-core rod (32) gradually abuts against the adjacent guiding inclined surface (341), causing the two sub-core rods (32) to move away from each other.

2. The large-diameter thick-wall pipe electrothermal necking-down device according to claim 1, characterized in that The sub-core rod (32) includes a rod body (321) and an elastic plate (322) fixed on the surface of the rod body (321). The elastic plate (322) is located on the side wall of the rod body (321) away from the fine-tuning insertion plate (34).

3. The large-diameter thick-wall pipe electric heat shrinking diameter reduction device according to claim 2, characterized in that, One end of the main core rod (31) is movably arranged on the fixing frame (13), and a driving member is arranged on the fixing frame (13). The driving member is used to drive the main core rod (31) to move in the horizontal direction.

4. The electrothermal necking-down device for large-diameter thick-wall pipes according to claim 1, wherein It further includes a pipe feeding system (4) arranged on the workbench (10), and the pipe feeding system (4) includes: A feeding box (41), located on one side of the pipe clamping device (2). The inner bottom wall of the feeding box (41) is set as a discharging inclined surface (411), a discharging port (412) is opened on the side wall of the feeding box (41), and a plurality of receiving plates (44) are spaced apart at the discharging port (412). The receiving plates (44) are fixed on the outer side wall of the feeding box (41); A collecting box (45), arranged below the workbench (10); A pipe transportation device is used to transport the pipes on the material receiving plate (44) to the pipe clamping device (2), and is also used to transport the pipes on the pipe clamping device (2) into the material receiving box (45).

5. The large-diameter thick-wall pipe electrothermal necking-down device according to claim 1, wherein, The reducing die (11) includes a die base (111) and a die body (114) arranged in the die base (111). The die base (111) is slidably connected to the workbench (10), and the fixing frame (13) is fixed to one side of the die base (111); An electric heating device (5) is arranged on one side of the die base (111) away from the fixing frame (13). The electric heating device (5) includes an electric heating table (51) and electric heating coils (52) arranged on the electric heating table (51).

6. The large-diameter thick-wall pipe electrothermal necking-down device according to claim 5, characterized in that, It further includes an outer wall lubricating device (6). The outer wall lubricating device (6) includes a first liquid replenishing tank (61), a first liquid infusion source (62) and a liquid sprayer (63). The first liquid replenishing tank (61) is fixed to the die base (111). The liquid sprayer (63) is arranged in the die base (111), and the liquid sprayer (63) includes a spraying channel (631) for the pipe to pass through. A plurality of first liquid spraying holes (632) are formed on the inner side wall of the spraying channel (631), and the spraying channel (631) is arranged collinearly with the reducing channel; The first liquid replenishing tank (61) is communicated with the liquid sprayer (63), and the first liquid infusion source (62) is arranged on the first liquid replenishing tank (61) for driving the liquid in the first liquid replenishing tank (61) to flow into the liquid sprayer (63).

7. The electric heat shrinking diameter equipment for large-diameter thick-wall pipes according to claim 1, characterized in that, It further includes an inner wall lubricating device (7). The inner wall lubricating device (7) includes a second liquid replenishing tank (71), a second liquid infusion source (72) and a liquid spraying box (73). The second liquid replenishing tank (71) is fixed to the fixing frame (13), and the liquid spraying box (73) is fixed to one end of the main mandrel (31) away from the fixing frame (13). A plurality of second liquid spraying holes (731) are formed on the outer side wall of the liquid spraying box (73); The second liquid replenishing tank (71) is communicated with the liquid spraying box (73), and the second liquid infusion source (72) is arranged on the second liquid replenishing tank (71) for driving the liquid in the second liquid replenishing tank (71) to flow into the liquid spraying box (73).

8. The electrothermal necking-down device for large-diameter thick-walled pipes according to claim 6, characterized in that, It further includes a lubricating liquid collecting device (8). The lubricating liquid collecting device (8) includes a liquid guiding trough body (81) and a liquid collecting pool (82); A set of liquid drainage holes (105) are formed on the workbench (10). The liquid guiding trough body (81) is fixed below the workbench (10) in an inclined state; One end of the liquid guiding trough body (81) is communicated with the set of liquid drainage holes (105), and the other end extends into the liquid collecting pool (82).

9. The large-diameter thick-wall pipe electrothermal necking-down device according to claim 5, characterized in that, A stroke control device (9) is further arranged on the workbench (10), and the stroke control device (9) is located on one side of the reducing device (1); The stroke control device (9) includes a stroke frame (91), an induction transmitter (92), and an induction receiver (93) disposed on the stroke frame (91); a connection bracket (112) is fixed to one side of each die base (111), and the induction receiver (93) is disposed on each connection bracket (112). Two induction transmitters (92) are spaced apart on the stroke frame (91); the induction transmitters (92) and the induction receivers (93) are in one-to-one correspondence and are used to transmit signals to the induction receivers (93).

10. A diameter reduction method, characterized in that, When using the large-diameter thick-wall pipe electrothermal necking equipment described in any one of claims 1-9 for pipe necking operations, the following steps are included: S1. Pipe feeding: Transport the pipe to be necked to the pipe clamping device (2) and make the pipe clamping device (2) clamp the pipe. S2. Necking operation: Start the necking device (1), drive the necking dies (11) at both ends of the workbench (10) to move towards each other, make the pipe enter the necking channel, continue to drive the necking dies (11) at both ends of the workbench (10) to move towards each other, and the necking dies (11) apply an inward pressure to the pipe ends, so that the diameter of the pipe ends gradually decreases until the required necking size is reached. S3. Device reset: After the necking operation is completed, drive the necking dies (11) at both ends of the workbench (10) to move away from each other, make the necking dies (11) move back to the initial position and disengage from the necked pipe. S4. Pipe unloading: Remove the necked pipe from the pipe clamping device (2) and transport the necked pipe away from the workbench (10).

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