Large diameter thick wall pipe electric heating shrinking device and shrinking method

Abstract

The present application relates to the technical field of non-cutting processing of metal tubes, and in particular to an electric heating shrinking device for large-diameter thick-walled tubes and a shrinking method thereof. The electric heating shrinking device for large-diameter thick-walled tubes comprises a workbench, a symmetrically arranged shrinking die and a drive unit, a tube clamping device and a supporting inner core system. The supporting inner core is composed of a main core rod, a secondary core rod and a reset part. The mounting grooves of the two main core rods are circumferentially staggered. The secondary core rod cooperates with the guide slope of the fine-tuning insert through a movable slide groove. When the shrinking die moves toward each other, the secondary core rod is prompted to expand radially to support the middle part of the tube. An electric heating device is equipped to reduce the deformation resistance of the tube. The inner and outer wall lubrication devices spray lubricating liquid on the inner and outer walls of the tube to reduce friction damage during processing. The lubricating liquid collection device realizes the environmentally friendly recycling of excess lubricating liquid. The present application realizes all-round support, temperature control and precise stroke adjustment of the tube during the shrinking process.

Description

Technical Field

[0001] The present application relates to the technical field of non-cutting processing of metal pipes, and in particular to an electric heating shrinking device for large-diameter thick-walled pipes and a shrinking method thereof. Background Art

[0002] A reducing machine is a non-cutting processing device with advantages such as high production efficiency, simple process, easy operation, material conservation, and consistent quality. During the reducing operation, the end of the pipe to be reduced is placed in a specially designed reducing die. The die's interior is shaped to match the desired outer diameter of the finished product. The reducing machine applies inward pressure to the end of the pipe. This pressure can be applied by hydraulics or other mechanical means. As the pressure increases, the pipe is forced into a cavity smaller than its original diameter, thereby reducing its diameter.

[0003] Reducing machines are designed to uniformly reduce the diameter of pipes. However, in practice, due to factors such as friction between the die and the pipe and the material's flow characteristics, the reduced end of the pipe may deform or collapse due to localized stress concentration. Therefore, some reducing machines use a mandrel inserted into the reduced end of the pipe during the reduction process to ensure the accuracy of the pipe's inner diameter and prevent uneven deformation of the reduced end during the reduction process.

[0004] When a double-head reducing machine is in use, pressure is applied inward from both ends simultaneously to perform the reducing operation. The place where the pipe is most susceptible to collapse is usually the middle part, because the middle part is farthest from the pressure sources at both ends. Even if a core shaft is inserted into the end of the pipe, the middle part of the pipe cannot get enough support during the reducing 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 bidirectional shrinking operation and reduce the defects caused by the shrinking process, the present application provides an electric heating shrinking device for large-diameter thick-walled pipes and a shrinking method thereof.

[0006] In a first aspect, the present application provides an electric heating shrinking device for large-diameter thick-walled pipes, which adopts the following technical solutions, including:

[0007] Workbench;

[0008] A diameter reduction device, comprising two diameter reduction dies spaced apart on the workbench, and a driving unit for driving the diameter reduction dies to slide, wherein one side of each of the diameter reduction dies is connected to a fixing frame, and the diameter reduction dies include a diameter reduction channel;

[0009] A pipe clamping device is provided between the two reducing dies for clamping the pipe, and the fixing frame is located on a side of the reducing dies away from the pipe clamping device;

[0010] There are two supporting inner cores relatively arranged, and the supporting inner cores correspond to the reducing mold one by one, and the supporting inner core comprises a main core rod, a secondary core rod and a reset member, and one end of the main core rod is connected to the fixed frame after passing through the reducing channel corresponding to the reducing mold; each of the main core rods is provided with a mounting groove for accommodating the secondary core rod, and the mounting grooves on the two main core rods are staggered in the circumferential direction; a movable slide groove is provided on the inner side wall of the mounting groove, and one end of the secondary core rod slides in the movable slide groove, and the reset member is used to drive the secondary core rod to slide in the direction away from the fixed frame; a fine-tuning plugboard is provided in the movable slide groove, and a guide inclined surface is provided at one end of the fine-tuning plugboard;

[0011] When the ends of the two supporting inner cores abut against each other and continue to move toward each other, the auxiliary core rods gradually abut against the adjacent guiding inclined surfaces, so that the two auxiliary core rods move away from each other.

[0012] By adopting the above technical solution, the diameter reduction device can make the diameter reduction die slide at both ends of the workbench, exerting pressure on the end of the pipe to reduce the diameter; the pipe clamping device can clamp the pipe to ensure the stable diameter reduction operation; the main core rod in the supporting inner core is connected to the fixed frame and passes through the diameter reduction channel, and the auxiliary core rod can slide in the installation sink and the movable slide groove, and the reset part is used to drive the auxiliary core rod to slide away from the fixed frame, so that the auxiliary core rod can be reset after sliding relative to the main core rod; when the two diameter reduction dies are driven to move toward each other, the two support rods are in the process of reducing the diameter of the pipe. The ends of the inner cores are pressed against each other, so that the supporting inner cores are distributed throughout the entire section of the pipe; then the two supporting inner cores continue to move toward each other, the ends of the pipe gradually enter the reducing channel, and the auxiliary core rods will gradually press against the adjacent guide slopes; through the cooperation of the main core rod, the auxiliary core rod and the fine-tuning insert, the two auxiliary core rods are gradually deflected and expanded in the radial direction during the process of the locking mold applying pressure to the pipe, so as to press against the inner wall of the middle part of the pipe, which can provide sufficient support for the middle part of the pipe in the bidirectional reducing operation, reduce the defects caused by the reducing process, and improve the reducing quality of the pipe.

[0013] Preferably, the auxiliary core rod comprises a rod body and an elastic plate fixed to the surface of the rod body, and the elastic plate is located on a side wall of the rod body away from the fine-tuning plug plate.

[0014] By adopting the above technical solution, when the two auxiliary core rods move away from each other and deflect, the outer wall of the auxiliary core rod will gradually come into contact with the inner side of the movable slide groove. The setting of the elastic plate allows the outer wall of the auxiliary core rod to deform within a certain range during the process of coming into contact with the inner side of the movable slide groove, which makes it less likely to damage the auxiliary core rod and the main core rod.

[0015] Preferably, one end of the main core rod is movably arranged on the fixing frame, and a driving member is provided on the fixing frame, and the driving member is used to drive the main core rod to move in the horizontal direction.

[0016] By adopting the above technical solution, the main core rod is movably connected to the fixed frame and is driven by the driving member to move horizontally, which can further flexibly adjust the position of the supporting inner core to better adapt to different diameter reduction 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 diameter reduction mold, the sliding range of the auxiliary core rod during the diameter reduction operation is controlled to control the radial deflection angle range of the two auxiliary core rods when they move away from each other, so that the auxiliary core rod deflects within an appropriate range to prevent the auxiliary core rod from being over-pressed and damaging the pipe, thereby further reducing the defects caused by the diameter reduction process.

[0017] Preferably, the apparatus further comprises a pipe feeding system provided on the workbench, wherein the pipe feeding system comprises:

[0018] A feeding box is located on one side of the pipe clamping device, the inner bottom wall of the feeding box is set as a discharge slope, a discharge port is opened on the side wall of the feeding box, and a plurality of receiving plates are arranged at intervals at the discharge port, and the receiving plates are fixed to the outer side wall of the feeding box;

[0019] A material receiving box is arranged below the workbench;

[0020] The pipe transport device is used to transport the pipes on the material receiving plate to the pipe clamping device, and is also used to transport the pipes on the pipe clamping device into the material receiving box.

[0021] By adopting the above technical solution, the bottom wall of the feeding box is set as a discharging slope to facilitate the discharge of pipes to the receiving plate. The pipe transport device can transport the pipes on the receiving plate to the pipe clamping device, which can automatically complete the pipe feeding. It can also transport the reduced-diameter pipes on the pipe clamping device to the receiving box under the workbench to realize automatic unloading, thereby improving the degree of automation and work efficiency of the pipe reducing operation.

[0022] Preferably, the reducing die comprises a die base and a die body disposed in the die base, the die base is slidably connected to the workbench, and the fixing frame is fixed to one side of the die base;

[0023] An electric heating device is provided on a side of the mold base away from the fixing frame. The electric heating device includes an electric heating table and an electric heating coil provided on the electric heating table.

[0024] By adopting the above technical solution, an electric heating device is set on the side of the mold base away from the fixed frame. The electric heating coil on the electric heating table can be used to heat the pipe, thereby reducing the deformation resistance of the pipe, making the diameter reduction process smoother, reducing deformation or collapse caused by local stress concentration during pipe diameter reduction, and improving the quality of the diameter reduction process.

[0025] Preferably, the outer wall lubrication device is further included, the outer wall lubrication device including a first liquid replenishing tank, a first infusion source and a liquid sprayer, the first liquid replenishing tank is fixed to the mold base, the liquid sprayer is arranged in the mold base, and the liquid sprayer includes 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 collinearly with the reduced diameter channel;

[0026] The first fluid replenishing tank is connected to the liquid sprayer, and the first infusion source is arranged on the first fluid replenishing tank, and is used to drive the liquid in the first fluid replenishing tank to flow into the liquid sprayer.

[0027] By adopting the above technical solution, 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 pipe passing through the injection channel, thereby reducing the friction between the reduction die and the pipe, avoiding the mold from scratching the outer wall of the pipe during the reduction process, and improving the reduction processing quality.

[0028] Preferably, it further comprises an inner wall lubricating device, the inner wall lubricating device comprising a second liquid replenishing tank, a second infusion source and a liquid spray box, the second liquid replenishing tank being fixed to the fixing frame, the liquid spray box being fixed to an end of the main core rod away from the fixing frame, and a plurality of second liquid spray holes being opened on the outer side wall of the liquid spray box;

[0029] The second fluid replenishing tank is connected to the liquid spraying box, and the second infusion source is provided on the second fluid replenishing tank for driving the liquid in the second fluid replenishing tank to flow into the liquid spraying box.

[0030] 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 supporting 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 supporting inner core can be more easily separated from the pipe.

[0031] Preferably, it also includes a lubricating liquid collection device, which includes a liquid guide trough body and a liquid collection pool; a drainage hole group is opened on the workbench, and the liquid guide trough body is fixed under the workbench in an inclined state; the drainage hole group is connected to one end of the liquid guide trough body, and the other end extends into the liquid collection pool.

[0032] By adopting the above technical solution, the liquid guide trough and liquid collection pool of the lubricating liquid collection 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.

[0033] Preferably, the workbench is further provided with a stroke control device, and the stroke control device is located on one side of the diameter reducing device;

[0034] The stroke control device includes a stroke frame, an inductive transmitter and an inductive receiver arranged on the stroke frame;

[0035] A connecting bracket is fixed on one side of each mold base, and the connecting bracket is provided with the induction receiver, and two induction transmitters are provided at intervals on the travel frame;

[0036] The induction transmitter corresponds to the induction receiver on a one-to-one basis and is used to transmit a signal to the induction receiver.

[0037] By adopting the above technical solution, the inductive transmitter of the stroke control device can transmit a signal to the corresponding inductive receiver, which can accurately control the moving stroke of the reduction die on the workbench, ensure that the reduction operation is carried out according to the preset distance, improve the accuracy and consistency of the reduction processing, and avoid processing errors and increased scrap rate caused by inaccurate stroke.

[0038] On the other hand, the present application provides a pipe reduction method, which uses the above-mentioned large-diameter thick-wall pipe electric heating pipe reduction equipment to perform pipe reduction operations, including the following steps:

[0039] S1. Tube feeding: transporting the tube to be reduced in diameter to the tube clamping device, and allowing the tube clamping device to clamp the tube;

[0040] S2, reducing operation, starting the reducing device, driving the reducing dies at both ends of the workbench to move toward each other, allowing the pipe to enter the reducing channel, and continuing to drive the reducing dies at both ends of the workbench to move toward each other, the reducing dies apply inward pressure to the end of the pipe, causing the diameter of the end of the pipe to gradually reduce until the required reduced diameter size is reached;

[0041] S3, the device is reset. After the diameter reduction operation is completed, the diameter reduction dies at both ends of the workbench are driven to move away from each other, so that the diameter reduction dies move back to the initial position and separate from the reduced pipe;

[0042] S4. Unloading of pipes: removing the pipes after diameter reduction from the pipe clamping device and transporting the pipes after diameter reduction away from the workbench.

[0043] By adopting the above technical solution, a series of operations such as pipe feeding, pipe shrinking, device resetting and unloading can be completed in an orderly manner using large-diameter thick-walled pipe electric heating shrinking equipment, thereby improving the efficiency and stability of the shrinking operation. At the same time, the supporting inner core in the equipment can provide support for the middle part of the pipe during the shrinking process, thereby reducing processing defects such as pipe deformation or collapse caused by two-way shrinking.

[0044] In summary, the present invention includes at least one of the following beneficial technical effects:

[0045] 1. The supporting core in this application moves with the reducing die to provide support for the interior of the tube to be reduced. When the ends of the two supporting cores abut against each other and continue to move, the auxiliary core rods move away from each other, effectively supporting the middle portion of the tube, reducing deformation or collapse caused by stress concentration, and minimizing reduction defects.

[0046] 2. The outer wall lubrication device in this application is installed on the die base. While the pipe is being fed into the reduction die, the lubricant is sprayed on the outer wall of the pipe. This can effectively reduce the friction between the reduction die and the outer wall of the pipe, preventing the reduction die from scratching the pipe during the reduction process, thereby improving the pipe reduction quality.

[0047] 3. This application also provides an inner wall lubrication device, which lubricates the inner wall of the pipe while the support core enters the pipe, greatly reducing the friction between the support core and the inner wall of the pipe. After the diameter reduction is completed, the support core is easier to remove from the inside of the pipe.

[0048] 4. This application installs an electric heating device on the side of the mold base away from the fixed frame. The electric heating coil on the electric heating table heats the pipe in the area to be reduced in diameter before it enters the mold body, reducing the deformation resistance of the pipe, making the reduction process smoother and reducing deformation or collapse caused by local stress concentration during pipe reduction.

[0049] 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 movement stroke of the diameter reduction die on the workbench, ensuring that the diameter reduction operation is carried out according to the preset distance, thereby improving the accuracy and consistency of the diameter reduction process;

[0050] 6. The present application uses a lubricating liquid collection device to collect excess lubricating liquid that flows onto the workbench during the pipe lubrication process for subsequent reuse, thereby improving the utilization rate of the lubricating liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] 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;

[0052] Figure 2 This is a schematic structural diagram of the material receiving box in Example 1 of the present application;

[0053] Figure 3 This is a schematic structural diagram of the pipe transport device in Example 1 of the present application;

[0054] Figure 4 Schematic diagram of the structure of the diameter reducing device in Example 1 of the present application;

[0055] Figure 5 This is a front view structural diagram of an electric heating shrinking device for large-diameter thick-walled tubes in Example 1 of the present application;

[0056] Figure 6 This is a schematic structural diagram of the outer wall lubrication device in Example 1 of the present application;

[0057] Figure 7 Schematic diagram of the structure of the inner wall lubrication device in Example 1 of the present application;

[0058] Figure 8 It is a partial cross-sectional structural schematic diagram of the inner wall lubrication device in Example 1 of the present application;

[0059] Figure 9 Schematic diagram of the structure of the cylinder-driven clamp in Example 1 of the present application;

[0060] Figure 10 Schematic diagram of the structure of the stroke control device in Example 1 of the present application;

[0061] Figure 11 Schematic diagram of the structure of the diameter reducing device in Example 3 of the present application;

[0062] Figure 12 is a schematic cross-sectional structural diagram of the support inner core in Example 3 of the present application;

[0063] Figure 13 yes Figure 12 Schematic diagram of the locally enlarged structure at point A in the middle.

[0064] Reference numerals in the accompanying drawings: 1, reducing device; 11, reducing die; 111, die base; 112, connecting bracket; 113, sliding sleeve; 114, die body; 115, die sleeve; 12, driving unit; 13, fixing bracket; 131, liquid guide slope; 1311, liquid through hole; 14, guide rod; 15, feed screw; 16, driving box; 161, slider; 162, rotating shaft;

[0065] 2. Pipe clamping device; 21. Driving cylinder; 22. Clamping claw;

[0066] 3. Supporting inner core; 31. Main core rod; 311. Mounting groove; 312. Movable slide; 32. Auxiliary core rod; 321. Rod body; 3211. Guide slope; 322. Elastic plate; 33. Reset member; 34. Fine-tuning plug plate; 341. Guide slope;

[0067] 4. Pipe feeding system; 41. Feed box; 411. Discharge ramp; 412. Discharge port; 413. First box; 414. Second box; 415. Pillar; 416. Roller; 42. Card strip; 421. Card slot; 43. Buckle; 431. Stop plate; 432. Card block; 44. Material receiving plate; 45. Material receiving box; 451. Hanging rod; 46. Screw slide module; 461. Servo motor; 47. Lifting mechanism; 471. Lifting frame; 472. Transmission assembly; 4721. Worm; 4722. Gear; 4723. Rack; 48. Vertical slide rail; 49. Limit loading mechanism; 491. Power source; 492. V-shaped limit plate;

[0068] 5. Electric heating device; 51. Electric heating table; 52. Electric heating coil; 53. Connecting rod; 54. Drive motor; 55. Cooling water tank; 551. Water inlet pipe; 552. Water outlet pipe;

[0069] 6. Outer wall lubrication device; 61. First fluid replenishment tank; 62. First infusion source; 621. Hydraulic inlet plate; 622. Lifting source; 63. Sprayer; 631. Spray channel; 632. First spray hole; 64. Fluid replenishment tube; 65. Liquid inlet tube;

[0070] 7. Inner wall lubrication device; 71. Second fluid replenishing tank; 72. Second infusion source; 73. Spray box; 731. Second spray hole; 74. Sleeve; 75. Hose; 76. Liquid supply pipe;

[0071] 8. Lubricating liquid collecting device; 81. Liquid guide trough; 82. Liquid collecting tank;

[0072] 9. Stroke control device; 91. Stroke frame; 911. Base frame; 912. Movable rod; 913. Scale plate; 92. Inductive transmitter; 93. Inductive receiver;

[0073] 10. Workbench; 101. Roller slide; 102. Discharge port; 103. Discharge slide; 104. Processing track; 105. Drain hole. DETAILED DESCRIPTION

[0074] The following is combined with Figure 1 -Attached Figure 11 The present invention is described in further detail.

[0075] Example 1

[0076] The present invention discloses an electric heat shrinking device for large-diameter thick-walled pipes. Referring to the drawings, the electric heat shrinking device for large-diameter thick-walled pipes comprises a workbench 10 , a shrinking device 1 , a pipe clamping device 2 , a pipe feeding system 4 , and a stroke control device 9 .

[0077] Reference Figure 1 and Figure 2 The pipe feeding system 4 includes a feed box 41, a pipe transport device, and a pipe receiving box 45. The feed box 41 and the pipe reducing device 1 are spaced apart on the workbench 10. A discharge port 412 is defined on the side wall of the feed box 41, adjacent to the pipe reducing device 1. A discharge slope 411 is provided on the inner bottom wall of the feed box 41. Multiple L-shaped receiving plates 44 are fixed to the discharge port 412 at intervals. The horizontal sections of these plates are fixedly connected to the side wall of the feed box 41.

[0078] Reference Figure 1 and Figure 2 The feed box 41 includes a first box body 413 and a second box body 414 arranged opposite to each other. The first box body 413 and the second box body 414 are configured as rectangular boxes with open tops, and the opposing side walls of the first box body 413 and the second box body 414 are also open. Four pillars 415 are fixed to the bottom of each of the first box body 413 and the second box body 414, and a roller 416 is rotatably connected to the bottom of each pillar 415. The workbench 10 is provided with a roller guide 101 for the rollers 416 to slide. The rollers 416 slide within the roller guide 101, achieving a sliding connection between the first box body 413 and the second box body 414 on the workbench 10. The size of the feed box 41 can be adjusted by sliding the first box body 413 or the second box body 414 and changing the distance between the first box body 413 and the second box body 414, so that the feed box 41 can be used for pipes of different sizes. To maintain the stability of the adjusted dimensions of the feed box 41, a clamping strip 42 is fixed to each side of the first box 413, and a buckle 43 is fixed to each side of the second box 414. The clamping strips 42 and buckles 43 are arranged in a one-to-one correspondence. The clamping strip 42 has multiple slots 421 spaced along its length, and the buckle 43 includes a rotatable stop plate 431. By rotating the stop plate 431, a block 432 is fixed to one side of the stop plate 431. By snapping the block 432 into one of the slots 421, the relative position of the first and second boxes 413, 414 is locked.

[0079] 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 slope 411 under the action of gravity and falls onto the receiving plate 44 to achieve automatic discharge.

[0080] Reference Figure 3The pipe transport device is located on the side of the feed box 41 close to the reducing device 1. The pipe transport device includes a screw slide module 46, a lifting mechanism 47 and a position limiting loading mechanism 49. Two screw slide modules 46 are arranged on the workbench 10 at intervals. The screw in the screw slide module 46 is arranged perpendicular to the roller slide rail 101, and two lifting mechanisms 47 and position limiting loading mechanisms 49 are also provided corresponding to the screw slide module 46. The lifting mechanism 47 is located on the slide in the corresponding screw slide module 46. The lifting mechanism 47 includes a lifting frame 471 and a transmission assembly 472. The lifting frame 471 is slidably connected to the slide in the screw slide module 46 through a vertical slide rail 48. In this embodiment, the transmission assembly 472 includes a worm 4721, a gear 4722 and a rack 4723 that are meshed in sequence. The worm 4721 is slidably connected to the lifting frame 471, the gear 4722 is rotationally connected to the lifting frame 471, and the rack 4723 is fixed to one side of the vertical slide rail 48. A driving source is fixed to one side of the lifting frame 471, and the driving gear 4722 is rotated to realize the raising and lowering of the lifting frame 471. The limiting loading mechanism 49 is located at the top of the lifting frame 471. The limiting loading mechanism 49 includes a power source 491 and a V-shaped limiting plate 492 that is rotatably connected to the lifting frame 471. The power source 491 can be a rotary motor. The V-shaped limiting plate 492 is driven by the rotary motor to rotate. The V-shaped limiting plate 492 can be adjusted to different usage states for receiving or unloading materials. The driving source can be a stepper motor.

[0081] Reference Figure 1 and Figure 3 A servo motor 461 is installed at one end of the screw slide module 46. At the same time, the servo motors 461 on the two sets of screw slide modules 46 are started to drive the limit loading mechanism 49 to slide close to the feed box 41; then the lifting mechanism 47 is used to drive the limit loading mechanism 49 to move upward, so that the V-shaped limit plate 492 supports the pipe on the receiving plate 44, and then the servo motors 461 on the two sets of screw slide modules 46 can be started again to transport the pipe to the reducing device 1 for reducing treatment.

[0082] Reference Figure 1 and Figure 4 The upper end surface of the workbench 10 is provided with a discharge port 102, which is located on the side of the reducing device 1 away from the feeding box 41. The pipe feeding system 4 also includes a receiving box 45. Figure 4 and Figure 5Two unloading slides 103 are fixed under 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 in the unloading slides 103 to realize the sliding connection of the material receiving box 45 under the workbench 10. The material receiving box 45 is configured as a rectangular box with an open top, and the opening of the material receiving box 45 is opposite to the unloading port 102. One end of the horizontal slide rail in the screw slide module 46 extends to the unloading port 102. When the pipe is reduced in diameter, the pipe transport device can transport the pipe to the unloading port 102; start the rotary motor to make the opening of the V-shaped limit plate 492 face the unloading port 102, and the reduced pipe can be unloaded into the material receiving box 45.

[0083] Reference Figure 4 and Figure 6 The reducing device 1 includes a reducing die 11 and a driving unit 12. Two reducing dies 11 are symmetrically arranged on the workbench 10, and two driving units 12 are also arranged corresponding to the reducing dies 11. The reducing die 11 includes a die base 111 and a die body 114. A hollow die sleeve 115 is fixed inside the die base 111. The die body 114 is fixed in the die sleeve 115. A reducing channel for the pipe to enter is processed in the die body 114. A fixing frame 13 is fixed on one side of the die base 111. Two processing rails 104 are fixed on the workbench 10. The bottom of the die base 111 is slidably connected to the processing rails 104. The driving unit 12 is fixed on the workbench 10. The driving unit 12 is specifically a feed cylinder. One end of the ejector rod of the driving unit 12 is fixed to the fixing frame 13 by welding or bolts.

[0084] Reference Figure 6 Each mold base 111 is provided with an outer wall lubricating device 6, which includes a first liquid replenishing tank 61, a first infusion source 62 and a liquid sprayer 63; the first liquid replenishing tank 61 is fixed to the top of the mold base 111, and the top of the first liquid replenishing tank 61 is connected to a liquid replenishing tube 64, and the bottom is fixed with a liquid inlet tube 65. The liquid sprayer 63 is fixed in the mold sleeve 115, and the liquid sprayer 63 is located on one side of the mold body 114. The liquid sprayer 63 is specifically configured as a cylindrical hollow shell, and the inner circle of the liquid sprayer 63 is configured as a spray channel 631 for the pipe to pass through, and a plurality of first liquid spray holes 632 are opened on the inner side wall of the spray channel 631. One end of the liquid inlet tube 65 is passed through the inner side of the mold sleeve 115 and is connected to the liquid sprayer 63. The first fluid replenishment tank 61 is open at the top. The first fluid infusion source 62 includes a hydraulic inlet plate 621 and a lifting source 622. The hydraulic inlet plate 621 is inserted into the opening of the first fluid replenishment tank 61 and is slidably connected to the first fluid replenishment tank 61. The lifting source 622 is fixed to the side wall of the first fluid replenishment tank 61, and the lifting end of the lifting source 622 is fixedly connected to the hydraulic inlet plate 621 via a connecting rod. Activating the lifting source 622 replenishes lubricating fluid into the sprayer 63, facilitating the lubrication of the outer wall of the tubing before it enters the mold body 114. The lifting source 622 can be an electric lifting cylinder.

[0085] Reference Figure 7 and Figure 8 , each fixed frame 13 is provided with an inner wall lubricating device 7, and the inner wall lubricating device 7 includes a second liquid replenishing tank 71, a second infusion source 72 and a spray box 73. The second liquid replenishing tank 71 is fixed to the fixed frame 13, and the structure of the second infusion source 72 is the same as that of the first infusion source 62, and the connection method of the second infusion source 72 on the second liquid replenishing tank 71 is the same as the connection method of the first infusion source 62 on the first liquid replenishing tank 61. Guide rods 14 and feed screws 15 are fixed on the fixed frame 13 at intervals, and the guide rods 14 and the feed screws 15 are arranged in parallel, and two guide rods 14 are arranged at intervals. A driving member is provided on the fixed frame 13, and the driving member is specifically configured as a driving box 16. Sliders 161 are provided on both sides of the driving box 16. The slides 161 are arranged in a 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. The drive housing 16 houses a motor and transmission components (not shown). The feed screw 15 extends through the drive housing 16 and is threadedly connected to the transmission components within. A rotating shaft 162 is also connected to the drive housing 16 for outputting rotation. A cylindrical support core 3 is coaxially secured to one end of the rotating shaft 162. The outer diameter of the support core 3 is slightly smaller than the inner diameter of the tubing to be reduced. A sleeve 74 is positioned over the rotating shaft 162, with a sealing ring secured to the connection between the sleeve 74 and the rotating shaft 162. A liquid inlet passage is defined within the rotating shaft 162 and communicates with the sleeve 74. A hose 75 is connected to the sleeve 74, one end of which is connected to the second liquid replenishing tank 71. A liquid supply tube 76 is secured within the support core 3. One end of the liquid supply tube 76 communicates with the liquid inlet passage and the other end with the liquid spray box 73. The support core 3 is cylindrical, and the spray box 73 is hollow cylindrical. The spray box 73 is fixed to one end of the support core 3 away from the rotation axis 162 . A plurality of second spray holes 731 are formed on the outer wall of the spray box 73 .

[0086] By starting the drive box 16, the support inner core 3 can be driven to slide in the direction away from the fixed frame 13, so that the support inner core 3 slides into the pipe. The support inner core 3 also rotates while sliding. After the spray box 73 enters the interior of the pipe, the second infusion source 72 is started to transport the lubricating liquid into the spray box 73 and spray the lubricating liquid on the inner wall of the pipe. The design of the support inner core 3 also effectively prevents the pipe from collapsing 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 interior 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 easier to detach from the inside of the pipe.

[0087] In other embodiments, the supporting core 3 may also be directly fixed on the fixing frame 13 .

[0088] Reference Figure 6 An electric heating device 5 is provided on the side of the mold base 111 away from the fixed frame 13. 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 on the connecting rod 53 and is electrically connected to the electric heating table 51. A driving motor 54 is installed in the electric heating table 51. Starting the driving motor 54 can drive the connecting rod 53 to rotate, so that the electric heating coil 52 is close to or away from the mold sleeve 115. The electric heating table 51 can be made of ceramic or plastic material with good insulation and heat resistance. The electric heating coil 52 can be made of copper coil. It can heat up quickly after being energized, preheat the pipe, reduce the hardness of the pipe, and facilitate the reduction operation.

[0089] Reference Figure 4 A cooling water tank 55 is also fixed to one side of the electric heating table 51. 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 passes through the connecting rod 53 and is connected to one end of the electric heating coil 52. One end of the outlet pipe 552 also passes through the connecting rod 53 and is connected to the other end of the electric heating coil 52. A water pump is installed in the cooling water tank 55. The outlet end of the water pump is connected to the inlet pipe 551, which can input water in the cooling water tank 55 into the inlet pipe 551. After the electric heating coil 52 is used, the water pump is started to transport the cooling water in the cooling water tank 55 along the inlet pipe 551 to the electric heating coil 52, and then discharged from the outlet pipe 552 into the cooling water tank 55, realizing the cooling water circulation.

[0090] Reference Figure 1 and Figure 4 The workbench 10 is also provided with a lubricating liquid collecting device 8, and a drainage hole group is provided on the workbench 10. The drainage hole group is located between two processing tracks 104 on the workbench 10. The drainage hole group includes a plurality of drainage holes 105. The drainage holes 105 are provided in circular and square shapes. Figure 4 and Figure 8 In order to facilitate the excess lubricating liquid flowing to the fixing frame 13 to flow into the drainage hole 105, a liquid guide slope 131 is processed on the fixing frame 13, and a liquid through hole 1311 is opened on the liquid guide slope 131. Figure 1 The lubricating liquid collection device 8 includes a liquid guide trough 81 and a liquid collection tank 82. One end of the liquid guide trough 81 is fixed to the bottom of the workbench 10, and two liquid guide troughs 81 are spaced apart below the workbench 10. The vertical projection of the drainage hole 105 is located on the inner bottom wall of the liquid guide trough 81, allowing the lubricating liquid to flow through the drainage hole 105 into the liquid guide trough 81. The liquid collection tank 82 is located below the liquid guide trough 81. One end of the liquid guide trough 81 slopes downward, away from the workbench 10, and extends into the liquid collection tank 82.

[0091] Reference Figure 1 and Figure 9 The pipe clamping device 2 is disposed between the two reducing dies 11. The pipe clamping device 2 includes two spaced-apart cylinder-driven clamps. The cylinder-driven clamps include a driving cylinder 21 and a closable clamping jaw 22. The driving cylinder 21 is located at the bottom of the workbench 10 and is fixedly connected to the workbench 10. The clamping jaw 22 is located above the workbench 10. Simultaneously activating the two driving cylinders 21 can open and close the clamping jaw 22, causing the clamping jaw 22 to clamp or release the pipe. When reducing the pipe, the pipe must be transported between the two reducing dies 11. After the pipe is clamped by the pipe clamping device 2, the drive box 16 and the drive unit 12 can be activated.

[0092] Reference Figure 1 and Figure 10 The workbench 10 is also provided with a stroke control device 9, which is located on the side of the pipe clamping device 2 away from the feed box 41. The stroke control device 9 includes a stroke frame 91, an inductive transmitter 92, and an inductive receiver 93. The stroke frame 91 includes a base frame 911, a movable rod 912 fixed to the base frame 911, and a long scale plate 913. The scale plate 913 has scale lines engraved along its length. A connecting bracket 112 is fixed to one side of each mold base 111. A sliding sleeve 113 is fixed to one end of the connecting bracket 112. The sliding sleeve 113 is sleeved on the movable rod 912 and slidably connected to the sliding rod. The bottom of each connecting bracket 112 is fixed with an inductive receiver 93. Two inductive transmitters 92 are slidably connected to the bottom of the scale plate 913. There is a certain amount of friction between the inductive transmitter 92 and the scale plate 913, which makes the position of the inductive transmitter 92 relatively stable after sliding. The inductive receiver 93 and inductive transmitter 92 are arranged in a one-to-one correspondence. The inductive receiver 93 is electrically connected to the drive unit 12 corresponding to the connected die base 111. The inductive transmitter 92 can be adjusted to the corresponding scale line on the scale bar according to the desired reduction distance. During the reduction process, the die base 111 drives the inductive receiver 93 to move. The inductive receiver 93 receives the signal sent by the inductive transmitter 92 to confirm the movement distance of the reduction die 11, thereby precisely controlling the reduction distance of the pipe. The inductive transmitter 92 can be a photoelectric sensor or an ultrasonic sensor.

[0093] The implementation principle of an electric heating shrinking device for large-diameter thick-walled pipes in the embodiment of the present application is as follows: during operation, the width of the feed box 41 and the initial spacing between the two shrinking dies 11 are first adjusted according to the size of the pipe so that the pipe can be placed smoothly. By sliding the first box body 413 and the second box body 414 and locking the spacing between the first box body 413 and the second box body 414 through the buckle 43 and the slot 421, multiple pipes can be stacked in the feed box 41. The pipe slides along the discharge slope 411 to the receiving plate 44. The two sets of screw slide modules 46 synchronously drive the limiting loading mechanism 49 to move toward the direction close to the feed box 41, and the V-shaped limiting plate 492 is lifted by the lifting mechanism 47 to lift the pipe and transport it to the shrinking station; the pipe is then clamped by the cylinder-driven clamp to position the pipe.

[0094] Subsequently, the two drive units 12 are simultaneously activated, causing the two reducing dies 11 to move toward each other, and synchronously applying pressure to form the pipe through the reducing 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, the first infusion source 62, the second infusion source 72, and the drive element are activated. The sprayer 63 forms an annular lubricating coating through the first spray hole 632. At the same time, the drive box 16 drives the rotating support inner core 3 carrying the spray box 73 to be inserted into the pipe, spraying the inner wall of the pipe through the second spray hole 731. The drive unit 12 drives the two side die bases 111 to move toward 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 reducing dies 11. After the pipe processing is completed, the pipe clamping device 2 releases the workpiece, and the screw slide module 46 transports the pipe in the opposite direction to the discharge port 102. The rotating V-shaped limit plate 492 unloads the finished product into the receiving box 45. Excess lubricant on the workbench 10 flows through the liquid guide slope 131 and the drain hole 105 into the liquid collection tank 82. Finally, the drive unit 12 resets the two reducing dies 11, and the pipe transport device returns to its initial position, completing the cycle. The entire process fully automates loading, positioning, lubrication, heating, reducing, and unloading, ensuring uniform stress distribution and controllable surface quality on the pipe.

[0095] Example 2

[0096] This embodiment discloses a method for reducing the diameter of a thick-walled pipe with an electrothermal shrinking device 1 having a relatively large diameter. The method uses the electrothermal shrinking device 1 having a relatively large diameter and a relatively thick-walled pipe in Example 1 to reduce the diameter of the pipe. The specific steps are as follows:

[0097] S1. Pipe feeding: transport the pipe to be reduced in diameter to the pipe clamping device 2, and allow the pipe clamping device 2 to clamp the pipe.

[0098] S11. Adjust the size of the feed box 41 by sliding the first box 413 and the second box 414 according to the length of the pipe to be reduced. Then, use the clamping strip 42 and the buckle 43 to fix the size of the feed box 41. Arrange multiple pipes to be reduced in the feed box 41. After the pipes are discharged from the discharge port 412, they are supported by the L-shaped receiving plate 44.

[0099] S12. The pipe transport device moves to the bottom of the material receiving plate 44 under the action of the screw slide module 46, and the V-shaped limit plate 492 on the lifting frame 471 lifts the pipe to be reduced in diameter, and then the screw slide module 46, the lifting mechanism 47 and the limit loading mechanism 49 cooperate to deliver the pipe to the clamping claw 22 of the pipe clamping device 2.

[0100] S13: Activate the driving cylinders 21 in each pipe clamping device 2 to close the clamping jaws 22 and clamp the pipe, ensuring that the pipe will not be displaced during the diameter reduction process.

[0101] 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 toward each other, so that the pipe enters the diameter reduction channel, and continue to drive the diameter reduction dies 11 at both ends of the workbench 10 to move toward each other. The diameter reduction dies 11 apply opposite inward pressure to the end of the pipe, so that the outer diameter of the end of the pipe is gradually reduced until the required diameter reduction size is reached.

[0102] S21, the driving unit 12 drives the supporting inner core 3, the outer wall lubrication device 6, the inner wall lubrication device 7, the reducing die 11 and the electric heating device 5 to move close to the end of the reduced diameter pipe. At this time, the driving box 16 is started to make the supporting inner core 3 rotate slowly along the reducing channel through the die body 114.

[0103] S22, the driving unit 12 continues to work to drive the two diameter-reducing dies 11 to move toward each other. While the diameter-reducing dies 11 are moving, the electric heating device 5 is energized, and the electric heating coil 52 preheats the pipe to be reduced in diameter.

[0104] S23, the reducing die 11 continues to feed, allowing the heated pipe to enter the reducing die 11, and the first infusion source 62 sprays the lubricating liquid in the first liquid replenishing tank 61 from the sprayer 63 through the liquid inlet pipe 65 to lubricate the outer wall of the pipe.

[0105] S24, while the reducing die 11 is being fed, the spray box 73 connected to one end of the supporting inner core 3 enters the interior of the pipe to be reduced in diameter; the second infusion source 72 is started, and the lubricating liquid in the second liquid replenishing tank 71 is sent to the sleeve 74 through the hose 75, and then sent to the spray box 73, and then the lubricating liquid is evenly sprayed onto the inner wall of the pipe through the second spray hole 731 on the spray box 73.

[0106] S25 , the driving unit 12 continues to move, and the two diameter-reducing dies 11 move toward each other, so that the pipe gradually enters the die body 114 , and the pipe diameter-reducing operation is performed.

[0107] S26. During the diameter reduction operation, the inductive receiver 93 moves together with the die base 111 until the inductive receiver 93 moves to the inductive transmitter 92 and receives the signal emitted by the inductive transmitter 92. Then, the required diameter reduction size is achieved and the diameter reduction operation is completed.

[0108] S3. The device resets. After the reduction operation is completed, the reduction dies 11 at both ends of the workbench 10 are driven to move away from each other, returning to their initial positions and separating from the reduced pipe. The drive unit 12 on the workbench 10 is retracted, driving the supporting core 3, outer wall lubrication device 6, inner wall lubrication device 7, reduction die 11, electric heating device 5, and induction receiver 93 to withdraw from the pipe.

[0109] S4, pipe unloading, removing the pipe after diameter reduction from the pipe clamping device 2, and transporting the pipe after diameter reduction away from the workbench 10.

[0110] S41. Loosen the clamping claws 22 in each cylinder-driven clamp, use the V-shaped limit plate 492 on the lifting frame 471 to lift the reduced-diameter pipe, and then send the reduced-diameter pipe to the discharge port 102 with the cooperation of the screw slide module 46, the lifting mechanism 47 and the limit loading mechanism 49. Start the rotary motor to rotate the V-shaped limit plate 492 toward the discharge port 102, and dump the pipe from the discharge port 102 on the workbench 10 into the receiving box 45 to complete the unloading.

[0111] S42. During the reduction operation, excess lubricating liquid will overflow. The lubricating liquid on the fixed frame 13 flows into the middle of the two processing tracks 104 on the workbench 10 through the liquid through-hole 1311 on the liquid guide slope 131, and then flows into the liquid guide trough 81 through the drainage hole group on the processing table, and finally flows along the liquid guide trough 81 to the liquid collecting pool 82.

[0112] Example 3

[0113] The embodiment of the present application discloses an electric heating shrinking device for large-diameter thick-walled pipes. The difference between this embodiment and embodiment 1 is that:

[0114] Reference Figure 11The outer diameter of the supporting inner core 3 is slightly smaller than the inner diameter of the pipe to be reduced. In this embodiment, one end of each supporting inner core 3 is extended in the direction away from the drive box 16 and passes through the die base 111. The length of the two processing rails 104 is extended, and the feed cylinder with a longer telescopic stroke is replaced to expand the sliding stroke of the reduction die 11. In this embodiment, the supporting inner core 3 includes a main core rod 31, a secondary core rod 32 and a reset member 33. One end of the main core rod 31 is fixed on the rotating shaft 162, and the end of the main core rod 31 away from the rotating shaft 162 is provided with a mounting groove 311. The mounting grooves 311 on the two main core rods 31 on the workbench 10 are staggered in the circumferential direction. In this embodiment, the secondary core rod 32 is set in a semi-cylindrical shape; correspondingly, the mounting grooves 311 on the two main core rods 31 are staggered 180° in the circumferential direction. When the auxiliary core rod 32 is configured in other shapes, the circumferential offset angles of the mounting recesses 311 on the two main core rods 31 can be designed to be adaptable to the shape of the auxiliary core rod 32 .

[0115] Reference Figure 11 and Figure 12 A movable slot 312 is provided on the inner wall of the mounting groove 311, and one end of the secondary core rod 32 slides in the movable slot 312. The secondary core rod 32 includes a rod body 321 and an arc-shaped elastic plate 322. A receiving slot is provided on the side wall of the rod body 321 away from the fine-tuning plug plate 34, and the elastic plate 322 is fixed in the receiving slot. 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 movable slot 312. In this embodiment, the reset member 33 is a reset spring, which is fixed between the inner wall of the movable slot 312 and the secondary core rod 32. When the secondary core rod 32 is squeezed by an external force, the spring is compressed. When the external force disappears, the spring returns to its original state, pushing the secondary core rod 32 back to its original position.

[0116] Reference Figure 12 and Figure 13 A fine-tuning plate 34 is fixed within the movable chute 312. A guide bevel 341 is machined on the end of the fine-tuning plate 34 near the auxiliary mandrel 32. A guide bevel 3211 is machined on the end of the auxiliary mandrel 32 near the reset member 33. The included angle between the guide bevel 3211 and the tilting direction and the guide bevel 341 ranges from 0 to 90°, specifically 15° in this embodiment. The fine-tuning plate 34 can be made of a lightweight material such as plastic or aluminum alloy.

[0117] In this embodiment, the liquid spray box 73 is configured as a semi-cylindrical box body. The liquid spray box 73 is embedded and fixed 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 .

[0118] During the reduction operation, the two drive units 12 and drive box 16 are activated, causing the ends of the two support cores 3 to abut against each other within the tube, distributing the support cores 3 throughout the entire tube section. Before activating the drive box 16, the placement angles of the two support cores 3 must be adjusted so that the secondary core rods 32 within one support core 3 align with the mounting recess 311 within the other support core 3. This facilitates the alignment of the two support cores 3, and after the drive box 16 is deactivated, the secondary core rods 32 within the support core 3 align with the mounting recess 311 within the other support core 3. The two drive units 12 continue to drive the support cores 3 toward each other, gradually allowing the ends of the tube to enter the reduction channel of the mold body 114. At this point, under the pressure of the opposing primary core rod 31, the secondary core rods 32 slide toward the fine-tuning plate 34, with each secondary core rod 32 gradually abutting against the guide slope 341 of the adjacent fine-tuning plate 34 as it slides. Through the mutual cooperation of the main core rod 31, the auxiliary core rod 32 and the fine-tuning insert plate 34, the two auxiliary core rods 32 are gradually deflected and expanded in the radial direction during the process of the locking mold applying pressure to the tube, so as to press against the inner tube wall in the middle of the tube, so that the ends of the auxiliary core rods 32 provide more effective support for the middle part of the tube.

[0119] By controlling the drive box 16, the length of the support core 3 extending beyond the die base 111 can be precisely adjusted. On the one hand, when the drive unit 12 drives the reduction die 11 to slide and move the support core 3 toward the pipe, the end of the pipe will not enter the constriction channel of the die body 114 (not shown) for constriction until the ends of the two support cores 3 abut against each other. Only after the ends of the two support cores 3 abut against each other can the pipe enter the constriction channel of the die body 114 as the support cores 3 continue to advance, ensuring that the support cores 3 effectively support the middle of the pipe during the constriction operation. On the other hand, when processing pipes of different lengths, adjusting the length of the supporting inner core 3 passing through the die base 111 can also control the distance that the two ends of the supporting inner core 3 need to continue feeding after they are against each other in the pipe to complete the pipe diameter reduction operation, thereby controlling the sliding range of the auxiliary core rod 32; thereby indirectly controlling the radial deflection angle range of the two auxiliary core rods 32 when they move away from each other, so that the auxiliary core rod 32 deflects within an appropriate range to prevent the auxiliary core rod 32 from causing excessive pressure on the inner wall of the pipe and damaging the pipe, further reducing the defects caused by the diameter reduction process.

[0120] The embodiments of this specific implementation method are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. An electric heating shrinking device for large diameter thick wall pipes, characterized in that: include: Workbench (10); A diameter reduction device (1) comprises two diameter reduction dies (11) spaced apart and arranged on the workbench (10), and a driving unit (12) for driving the diameter reduction dies (11) to slide, wherein one side of each of the diameter reduction dies (11) is connected to a fixing frame (13), and the diameter reduction dies (11) include a diameter reduction channel; A pipe clamping device (2) is provided between the two reducing dies (11) and is used for clamping the pipe, and the fixing frame (13) is located on a side of the reducing dies (11) away from the pipe clamping device (2); Two supporting inner cores (3) are arranged opposite to each other, and the supporting inner cores (3) correspond to the reducing mold (11) one by one. The supporting inner core (3) includes a main core rod (31), a secondary core rod (32) and a reset member (33). One end of the main core rod (31) passes through the reducing channel corresponding to the reducing mold (11) and is connected to the fixing frame (13); each main core rod (31) is provided with a mounting groove (311) for accommodating the secondary core rod (32), and the two main core rods The mounting groove (311) on the (31) is staggered in the circumferential direction; a movable slide groove (312) is provided on the inner side wall of the mounting groove (311), one end of the auxiliary core rod (32) slides in the movable slide groove (312), and the reset member (33) is used to drive the auxiliary core rod (32) to slide in a direction away from the fixed frame (13); a fine-tuning plug plate (34) is provided in the movable slide groove (312), and a guide inclined surface (341) is provided at one end of the fine-tuning plug plate (34); When the ends of the two supporting inner cores (3) abut against each other and continue to move toward each other, the auxiliary core rods (32) gradually abut against the adjacent guide inclined surfaces (341), so that the two auxiliary core rods (32) move away from each other; It also includes an inner wall lubricating device (7), the inner wall lubricating device (7) including a second liquid replenishing tank (71), a second infusion source (72) and a liquid spray box (73), the second liquid replenishing tank (71) is fixed on the fixing frame (13), the liquid spray box (73) is fixed to an end of the main core rod (31) away from the fixing frame (13), and a plurality of second liquid spray holes (731) are opened on the outer side wall of the liquid spray box (73); The second liquid replenishing tank (71) is connected to the liquid spraying box (73), and the second infusion source (72) is arranged on the second liquid replenishing tank (71) and is used to drive the liquid in the second liquid replenishing tank (71) to flow into the liquid spraying box (73).

2. The large diameter thick wall pipe electric heating shrinking equipment according to claim 1 is characterized in that: The auxiliary core rod (32) comprises a rod body (321) and an elastic plate (322) fixed to the surface of the rod body (321); the elastic plate (322) is located on a side wall of the rod body (321) away from the fine-tuning plug plate (34).

3. The large diameter thick wall pipe electric heating shrinking equipment according to claim 1 is characterized in that: One end of the main core rod (31) is movably arranged on the fixing frame (13), and a driving member is provided on the fixing frame (13), and the driving member is used to drive the main core rod (31) to move in a horizontal direction.

4. The large diameter thick wall pipe electric heating shrinking equipment according to claim 1 is characterized in that: It also includes a pipe feeding system (4) arranged on the workbench (10), and the pipe feeding system (4) includes: A feeding box (41) is located on one side of the pipe clamping device (2), the inner bottom wall of the feeding box (41) is set as a discharge slope (411), a discharge port (412) is opened on the side wall of the feeding box (41), and a plurality of receiving plates (44) are arranged at intervals at the discharge port (412), and the receiving plates (44) are fixed on the outer side wall of the feeding box (41); A material receiving box (45) is arranged below the workbench (10); The pipe transport device is used to transport the pipe on the material receiving plate (44) to the pipe clamping device (2), and is also used to transport the pipe on the pipe clamping device (2) to the material receiving box (45).

5. The large diameter thick wall pipe electric heating shrinking equipment according to claim 1 is characterized in that: The reducing die (11) comprises a die base (111) and a die body (114) disposed 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 provided on a side of the mold base (111) away from the fixing frame (13), and the electric heating device (5) comprises an electric heating table (51) and an electric heating coil (52) provided on the electric heating table (51).

6. The large diameter thick wall pipe electric heating shrinking equipment according to claim 5, characterized in that: The outer wall lubricating device (6) further comprises an outer wall lubricating device (6), the outer wall lubricating device (6) comprising a first liquid replenishing tank (61), a first infusion source (62) and a liquid sprayer (63), the first liquid replenishing tank (61) being fixed on the die base (111), the liquid sprayer (63) being arranged in the die base (111), and the liquid sprayer (63) comprising a spray channel (631) for the pipe to pass through, a plurality of first liquid spray holes (632) being opened on the inner side wall of the spray channel (631), and the spray channel (631) being arranged collinearly with the diameter-reducing channel; The first fluid replenishing tank (61) is connected to the liquid sprayer (63), and the first infusion source (62) is arranged on the first fluid replenishing tank (61) and is used to drive the liquid in the first fluid replenishing tank (61) to flow into the liquid sprayer (63).

7. The large diameter thick wall pipe electric heating shrinking equipment according to claim 6, characterized in that: The invention also includes a lubricating liquid collecting device (8), wherein the lubricating liquid collecting device (8) includes a liquid guide trough body (81) and a liquid collecting pool (82); a group of drainage holes (105) is provided on the workbench (10), and the liquid guide trough body (81) is fixed below the workbench (10) in an inclined state; one end of the liquid guide trough body (81) is connected to the group of drainage holes (105), and the other end extends into the liquid collecting pool (82).

8. The large diameter thick wall pipe electric heating shrinking equipment according to claim 5, characterized in that: The workbench (10) is further provided with a stroke control device (9), and the stroke control device (9) is located on one side of the diameter reducing device (1); The stroke control device (9) includes a stroke frame (91), an inductive transmitter (92) and an inductive receiver (93) arranged on the stroke frame (91); a connecting bracket (112) is fixed to one side of each mold base (111), and the inductive receiver (93) is arranged on the connecting bracket (112), and two inductive transmitters (92) are arranged at intervals on the stroke frame (91); the inductive transmitters (92) correspond to the inductive receivers (93) one by one and are used to transmit signals to the inductive receivers (93).

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