Tractor tension control system and three-layer co-extrusion dry-method crosslinking production line

Abstract

The utility model relates to the technical field of draggers, in particular to a dragger tension control system and a three-layer co-extrusion dry-method crosslinking production line, and the dragger tension control system comprises a dragger and a tension control system; wherein the traction machine comprises a traction machine rack, a traction device and a driving system mounted on the traction device; the traction device is installed on the traction machine rack and used for moving a load, and the driving system is used for driving the traction device to move; the traction device comprises a driving wheel, a driven wheel and a transmission device, and the transmission device acts between the driving wheel and the driven wheel and is used for transmitting power; the tension control system is installed on the driven wheel and comprises a speed reducer and a tension adjusting device connected with the driven wheel, and the tension adjusting device is arranged on an output shaft of the speed reducer. According to the utility model, the problem of unstable transmission caused by too large reverse tension or insufficient positive tension in the transmission control of the tractor is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a traction machine technical field especially relates to a traction machine tension control system and three layer co -extrusion dry method crosslinking production line. BACKGROUND

[0002] The traction machine used on the existing crosslinked cable production line is mainly adjusted by a traditional mechanical speed controller. For example, the patent with the publication number CN110697496A sets a tensioning mechanism 5, so that the tension of the upper track 2 and the lower track 3 can be adjusted by starting the top cylinder 8. The top cylinder 8 drives the pneumatic rod 9 to extend, thereby driving the traction rod 10 to rotate around the shaft between the traction rod 10 and the connecting rod. The traction rod 10 drives the traction wheel 11 to rotate around the shaft between the traction rod 10 and the connecting rod during rotation around the shaft. The active direction of the traction wheel 11 is inclined and active from the left wheel 6 to the top cylinder 8, so that the upper track 2 and the lower track 3 are arched, achieving the purpose of tensioning the track. This mechanical speed controller has the following defects: when the traction machine has insufficient transmission power, the traction machine may have overcurrent or slip phenomenon; when the traction machine is being dragged, the main motor may be in a passive power generation state. These two states will cause unstable transmission operation, and the problems of too large reverse tension or insufficient positive tension causing unstable transmission.

[0003] The utility model provides a traction machine tension control system and three layer co -extrusion dry method crosslinking production line to solve the above technical problems. INVENTION CONTENTS

[0004] The utility model provides a traction machine tension control system and three layer co -extrusion dry method crosslinking production line to solve the above technical problems.

[0005] A traction machine tension control system: including traction machine and tension control system, wherein the traction machine includes traction machine frame, traction device and drive system installed on the traction device, the traction device is installed on the traction machine frame and is used for moving load, and the drive system is used to drive the traction device to move, the traction device includes driving wheel, driven wheel and transmission device, the transmission device acts between the driving wheel and the driven wheel and is used to transmit power, the tension control system is installed on the driven wheel, the tension control system includes speed reducer and tension adjusting device connected with the driven wheel, and the tension adjusting device is arranged on the output shaft of the speed reducer.

[0006] On the basis of the above technical solutions, the tension control system further comprises a control unit, which is electrically connected with the tension adjusting device and used for monitoring and adjusting the operating state of the tension adjusting device to maintain a predetermined tension level.

[0007] Further, the tension control system is a positive tension control system or a negative tension control system; the driving force direction of the driving system is the same as the tension applying direction of the positive tension control system; and the driving force direction of the driving system is opposite to the tension applying direction of the negative tension control system.

[0008] Preferably, the tension adjusting device is one of an electromagnetic brake, a slip head, a magnetic powder brake, a motor or a hysteresis tensioner.

[0009] The three-layer co-extrusion dry crosslinking production line comprises, in sequence, a pay-off machine, a line accumulator, an upper traction machine, three extruders, a three-layer co-extrusion head, a closed crosslinking pipeline, a heating pipeline, a pre-cooling pipeline, a cooling pipeline, a lower traction machine and a take-up machine, the upper traction machine is connected with the negative tension control system, and the lower traction machine is connected with the positive tension control system.

[0010] Advantages

[0011] Compared with the prior art, the utility model has the advantages that: on the one hand, dynamic balance is used for tension control: by applying positive / negative tension on the driven wheel, a dynamic balance mechanism can be formed, so that the system can be more accurately controlled. This setting helps to maintain a constant transmission level, even in the case of load changes or speed fluctuations. On the other hand, the device has flexibility and adaptability: this method is suitable for various types of traction machines such as track traction machines and belt traction machines, and has wide applicability and good compatibility. Different types of tension adjusting devices (such as electromagnetic brakes, slip heads, magnetic powder brakes or hysteresis tensioners, motors) can be selected according to specific application scenarios to meet specific process requirements. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only one embodiment of the utility model, and for those skilled in the art, other implementation drawings can be obtained from the provided drawings without creative labor.

[0013] Figure 1 The structure diagram of the track traction machine is shown in the utility model.

[0014] Figure 2: Installation diagram of the track traction machine and tension control system described in this utility model;

[0015] Figure 3 : Installation diagram of the dual-drive strapping traction machine and tension control system described in this utility model;

[0016] Figure 4 : A schematic diagram of the tension control system described in this utility model;

[0017] Figure 5 : A schematic diagram of the structure of the strap traction machine described in this utility model;

[0018] Figure 6 : Installation diagram of the strapping traction machine and tension control system described in this utility model;

[0019] Figure 7 : A schematic diagram of the structure of the three-layer co-extrusion dry crosslinking production line of this utility model. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and examples:

[0021] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0022] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0023] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0024] Example 1

[0025] A tension control system for a traction machine is characterized by comprising a traction machine and a tension control system; wherein the traction machine includes a traction machine frame, a traction device, and a drive system mounted on the traction device; the traction device is mounted on the traction machine frame and is used to transmit a load, and the drive system is used to drive the traction device to move; the traction device includes a driving wheel, a driven wheel, and a transmission device, the transmission device acting between the driving wheel and the driven wheel to transmit power; the tension control system is mounted on the driven wheel, and the tension control system includes a reducer 1 connected to the driven wheel and a tension adjusting device 2, the tension adjusting device being disposed on the output shaft of the reducer.

[0026] The driving force direction of the drive system is the same as or opposite to the tension application direction of the tension control system. That is, when the drive system provides insufficient forward or tensile driving force, the tension control system provides the same tensile force to maintain or adjust the required tension level; that is, when the drive system is being dragged, the tension control system provides the same counter-tension to maintain or adjust the required tension level.

[0027] like Figure 4 As shown, the tension adjustment device is one of an electromagnetic brake, a slip head, a magnetic powder brake, a hysteresis tensioner, or an electric motor.

[0028] The working principle of an electromagnetic brake is based on the magnetic field generated when electricity is applied, which acts on a steel element to cut magnetic lines of force, thereby generating a braking torque. By adjusting the voltage supplied to the electromagnet, which is usually a DC voltage, the magnitude of the electromagnetic force can be changed, thus affecting the braking effect.

[0029] The principle of a slip head is the same as that of an electromagnetic brake.

[0030] Magnetic particle brakes utilize changes in the magnetic field to alter the friction between the internal magnetic particles, thereby adjusting the transmitted torque. The greater the current applied to the coil, the stronger the attraction between the magnetic particles, and the greater the resistance generated.

[0031] Hysteresis tensioners rely on the hysteresis effect between a permanent magnet and a soft magnetic material to generate constant resistance. Although the hysteresis characteristic itself has a certain degree of nonlinearity, the output tension can still be controlled within a certain range by adjusting the current in the excitation coil.

[0032] The tension control system further includes a control unit electrically connected to the tension regulating device. The control unit monitors and adjusts the operating state of the tension regulating device to maintain a predetermined tension level. The control unit can be a pressure regulating unit, which controls the output tension of the tension regulating device.

[0033] like Figure 1As shown, the traction machine is a tracked traction machine, which includes a tracked traction machine frame 31. The tracked traction machine frame 31 is equipped with a track drive wheel 32, a track driven wheel 33, and a track 34 positioned between the track drive wheel 32 and the track driven wheel 33. The track drive wheel 32, the track driven wheel 33, and the track 34 are arranged in two sets, upper and lower, and are synchronized to rotate in opposite directions through meshing gears. A track drive motor is mounted on the track drive wheel 32.

[0034] like Figure 2 As shown, a tension control system is installed on the track passive wheel 33.

[0035] The tracked traction machine also includes an adjusting plate, which comprises adjusting cylinders arranged side-by-side on the upper and lower parts of the tracked traction machine frame 31. The output end of each adjusting cylinder is connected to a top plate. The size of the area through which the load passes is adjusted by changing the distance between the upper and lower adjusting plates.

[0036] The tracked traction machine frame 31 provides the support framework for the entire system. The track drive sprocket 32 ​​and track driven sprocket 33 are mounted on the frame to drive and guide the tracks. The track 34 is positioned between the drive and driven sprockets, forming a closed-loop structure to bear and move the load. The upper and lower track systems rotate synchronously in opposite directions via meshing gears, ensuring smooth operation. The track drive motor is mounted on the track drive sprocket, providing driving force to rotate the tracks. The motor's speed and torque directly affect the track's speed and load-bearing capacity. When the motor starts, it drives the track drive sprocket 32 ​​to rotate, thereby transmitting power to the track driven sprocket 33 through the track 34, enabling the track to move along a predetermined path. The arrangement of the upper and lower track systems traction and moves the load.

[0037] The tension control system is mounted on the track driven wheel 33. The tension adjustment device can adjust the forward and reverse tension according to actual needs to ensure a constant and appropriate transmission level throughout the entire conveyor belt operation. The control unit monitors and automatically adjusts the operating status of the tension adjustment device in real time to cope with any factors that may affect the tension, such as speed changes or load changes.

[0038] The main motor current signal of the traction machine is monitored in real time, and the tension is adjusted by PID calculation to achieve stable operation of the traction machine.

[0039] Example 2

[0040] like Figure 3As shown, the traction machine is a dual-drive belt traction machine. The dual-drive belt traction machine includes a dual-drive belt traction machine frame 41, an inner belt traction device, and an outer belt traction device. The inner belt traction device includes an inner belt drive wheel 431, an inner belt driven wheel 432, a center wheel 42, and an arc-shaped roller 433 sequentially arranged on the dual-drive belt traction machine frame 41. The arc-shaped roller 433 is located around the center wheel 42. An inner belt 46 is mounted on the shaped roller 433. The outer belt traction device includes an outer belt drive wheel 451, a first outer belt driven wheel 452, a second outer belt driven wheel 453, and a fourth outer belt driven wheel 454, all mounted on the dual-drive wrapping belt traction machine frame 41. An outer belt 44 is mounted on the outer belt drive wheel 451 and the driven wheel. A dual-drive wrapping belt traction machine drive motor is mounted on both the outer belt drive wheel 451 and the inner belt drive wheel 431. A tension control system is mounted on the first outer belt driven wheel 452. The inner belt 46 is arc-shaped, and the outer belt 44 is U-shaped. The load runs between the inner belt 46 and the outer belt 44.

[0041] The dual-drive belt traction machine frame 41 is also equipped with a first adjusting cylinder 461 and a second adjusting cylinder 462. The free end of the piston rod of the first adjusting cylinder 461 is connected to the center wheel 42, and the free end of the piston rod of the second adjusting cylinder 462 is connected to the fourth outer passive wheel 454. The center wheel 42 and the fourth outer passive wheel 454 are slidably connected to the dual-drive belt traction machine frame 41.

[0042] The dual-drive belt traction machine frame 41 serves as the support frame for the entire system, ensuring the stable installation of all components. The inner and outer belt traction devices each consist of one or more sets of wheels, including drive wheels, driven wheels, center wheels, and auxiliary rollers, which work together on the inner belt 46 and outer belt 44 to clamp and move the load. The dual-drive belt traction machine drive motor is mounted on the outer belt drive wheel 451 and the inner belt drive wheel 431, providing the necessary driving force.

[0043] Cables or materials to be processed are drawn from upstream equipment, such as a cable feeder, and enter the inlet of the dual-drive wrapping tape traction machine. At this point, the cable is positioned between the inner and outer tapes, awaiting clamping and transport. When the drive motor starts, the inner tape drive wheel 431 and the outer tape drive wheel 451 rotate synchronously, driving their respective wrapping tapes 46 and 44. These tapes gently clamp the cable, ensuring it travels along the correct path.

[0044] The tension control system is installed on the first outer belt driven pulley 452 and connected to a tension adjustment device such as an electromagnetic brake, slip head, magnetic powder brake, hysteresis tensioner, or electric motor via a reducer. The control unit monitors and adjusts the operating status of the tension adjustment device in real time, monitors the main motor current signal of the traction machine in real time, and uses PID calculation to adjust the tension to achieve stable operation of the traction machine. As the strapping belt continues to move, the cable is gradually conveyed forward.

[0045] Example 3

[0046] like Figure 5 As shown, the traction machine is a strapping traction machine. The strapping traction machine support 51 is equipped with a strapping traction machine center wheel 52 and a strapping traction device. The strapping traction device includes a first strapping drive wheel 53, a second strapping driven wheel 54, a third strapping driven wheel 55, a fourth strapping driven wheel 56, and an outer strapping traction machine 57. The strapping traction machine center wheel 52 is equipped with an inner strapping traction machine. The outer strapping traction machine 57 is mounted on the driven wheel, which is positioned around the center wheel 52. Both the center wheel 52 and the first strapping drive wheel 53 are equipped with strapping drive motors. A tension control system is installed on the fourth strapping driven wheel 56.

[0047] The tape traction machine bracket 51 is provided with a slide rail, the second tape driven wheel 54 is slidably connected to the slide rail, the cylinder body of the tape tensioning cylinder is connected to the tape traction machine bracket 51, and the free end of its piston rod is connected to the second tape driven wheel 54.

[0048] The tape traction machine bracket 51 provides the support frame for the entire system. The tape traction machine center wheel 52, first tape drive wheel 53, and tape driven wheels 54, 55, and 56 work together to clamp and move the load using the outer and inner tape of the tape traction machine. Cables or materials to be processed are drawn from upstream equipment, such as a cable feeder, and enter the inlet position of the tape traction machine. At this point, the cable is positioned between the inner and outer tapes 57, awaiting clamping and transport. Tape drive motors are mounted on both the center wheel 52 and the first tape drive wheel 53. When the drive motors start, the motor on the center wheel 52 rotates the inner tape. The motor on the first tape drive wheel rotates the outer tape 57. The inner and outer tapes gently clamp the cable, ensuring it is aligned on the correct path and begins to move. The tension control system is installed on the fourth belt drive pulley 56. The control unit monitors and adjusts the operating status of the tension adjustment device in real time, and uses the main motor current signal of the traction machine for real-time monitoring. It uses PID calculation to adjust the tension to achieve stable operation of the traction machine. As the belt continues to move, the cable is gradually conveyed forward.

[0049] The free end of the piston rod of the tape tensioning cylinder is connected to the second tape driven pulley 54, and the connection is achieved through a slide rail. This design allows for fine-tuning of the position of the second tape driven pulley according to actual needs, further optimizing the tension distribution.

[0050] Alternatively, a drive motor can be used, mounted in a fixed position, with its output shaft connected to a main gear via a coupling. The main gear meshes with two driven gears, which are respectively mounted on the shafts of the central wheel 52 of the wrapping traction machine and the first wrapping drive wheel 53. Alternatively, chain drive or belt drive can be used.

[0051] Example 4

[0052] like Figure 7 As shown, the three-layer co-extrusion dry crosslinking production line includes, in sequence, a wire feeding machine 61, a wire storage device 62, an upper traction machine 63, three extruders, a three-layer co-extrusion die head 64, a seal 65, crosslinking pipelines, heating pipelines 67, precooling pipelines 68, cooling pipelines 69, a lower traction machine 66, and a take-up machine. The upper traction machine 63 is connected to a counter-tension control system. The upper traction machine 63 can be selected from the tracked traction machine, dual-drive wrapping traction machine, and wrapping traction machine described in Examples 1 to 3 above.

[0053] Cable or conductor is drawn out of the pay-off machine 61, ensuring a continuous and stable supply. Cable reservoir 62 buffers the cable supply, preventing tension fluctuations due to speed variations. Upper traction machine 63 gently clamps the cable via a track or other clamping device and feeds it forward at a constant speed. This stage begins to apply initial tension control to the cable. Three extruders and a three-layer co-extrusion die 64: This is the core of the production line, responsible for simultaneously extruding three different materials—an inner insulation layer, a middle shielding layer, and an outer protective layer—on a single cable. Each layer is supplied by a corresponding extruder according to a specific formulation and precisely assembled at the co-extrusion die head. During extrusion, molten plastic material is uniformly coated onto the cable surface, forming the required thickness and shape. Sealing 65: The extruded cable enters a sealed environment to prevent external air from interfering with the cross-linking reaction. Cross-linking conduit: In this area, the cable undergoes a chemical or physical cross-linking process, forming a cross-linked network structure between polymer molecular chains, thereby improving the material's mechanical strength, heat resistance, and electrical properties. Heating pipe 67: If thermal cross-linking is used, the cable will pass through the heating pipe to accelerate the cross-linking reaction in a high-temperature environment. After cross-linking is completed, the cable will immediately enter the pre-cooling pipe for initial cooling to fix its shape and reduce subsequent cooling time.

[0054] After pre-cooling, the cable continues to undergo final cooling and shaping in cooling pipe 69. This step ensures that the cable has stable dimensions and good appearance quality.

[0055] The lower traction machine 66 is mainly used for the final transportation and sorting of finished cables. The take-up machine neatly winds the processed finished cables onto reels for easy storage and transportation.

[0056] The tension control system is installed on the upper traction machine 63. It can monitor and adjust the tension level of each section in real time through precision sensors and controllers to ensure that the cable always maintains an ideal tension state throughout the production process, unaffected by speed changes or load.

[0057] This device employs advanced electromagnetic brakes, slip heads, magnetic powder brakes, hysteresis tensioners, or electric motors as tension adjustment devices, enabling more precise tension control. It includes a control unit capable of real-time monitoring and adjustment of the tension adjustment device's operating status, ensuring the predetermined tension level is consistently maintained. The driving force direction of the drive system and the tension application direction of the tension control system are related to the operating conditions, forming a dynamic balance that helps improve system stability and response speed. Different application scenarios for various types of traction machines, such as tracked traction machines and dual-drive belt traction machines, have been considered, and specific structural optimizations have been provided for each application scenario.

[0058] Tension control systems are divided into positive tension adjustment systems and negative tension adjustment systems.

[0059] The positive tension adjustment system, mounted on the driven pulley, provides auxiliary traction when the traction machine's power transmission is insufficient. The motor's torque, transmitted through a reducer, acts on the pulley, allowing the driven belt to provide some tension for operation. The motor can be torque-controlled; based on the main motor's current signal, a PLC calculates that when the main motor's current reaches a set value, the positive tension adjustment system maintains the main motor's current within the set value through torque output.

[0060] The anti-tension adjustment system, mounted on the driven pulley, provides counter-tension when the traction machine is being towed. This counter-tension is achieved through the torque of an eddy current brake, slip head, magnetic powder brake, and hysteresis tensioner, which, via a reducer, acts on the pulley, allowing the driven belt to provide a certain amount of counter-tension for operation. This functions as a reverse auxiliary traction mechanism. Based on the main motor's current signal, the PLC calculates that when the main motor's current falls below a set value, the anti-tension adjustment system maintains the main motor's current within the set value through torque output.

[0061] The positive tension adjustment system is suitable for the lower traction machine, while the negative tension adjustment system is suitable for both the upper and lower traction machines.

[0062] It should be noted that the electromagnetic brake, slip head, magnetic powder brake or hysteresis tensioner, electric motor, drive main motor and reducer in this embodiment are all general standard parts or components known to those skilled in the art. Their structure and principle can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0063] The present invention has been described above by way of example, but the present invention is not limited to the specific embodiments described above. Any modifications or variations made based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A traction machine tension control system, characterized in that: The system includes a traction machine and a tension control system; the traction machine includes a traction machine frame, a traction device, and a drive system mounted on the traction device; the traction device is mounted on the traction machine frame and is used to move the load, and the drive system is used to drive the traction device to move; the traction device includes a driving wheel, a driven wheel, and a transmission device, the transmission device acting between the driving wheel and the driven wheel to transmit power; the tension control system is mounted on the driven wheel, and the tension control system includes a reducer (1) connected to the driven wheel and a tension adjusting device (2), the tension adjusting device (2) being disposed on the output shaft of the reducer.

2. The traction tension control system according to claim 1, characterized in that... The tension control system further includes a control unit, which is electrically connected to the tension regulating device and is used to monitor and adjust the operating status of the tension regulating device to maintain a predetermined tension level.

3. A traction machine tension control system according to claim 2, characterized in that... The tension control system is either a positive tension control system or a negative tension control system; the driving force direction of the drive system is the same as the tension application direction of the positive tension control system; the driving force direction of the drive system is opposite to the tension application direction of the negative tension control system.

4. A traction machine tension control system according to claim 3, characterized in that... The tension adjustment device is one of the following: electromagnetic brake, slip head, magnetic powder brake, electric motor, or hysteresis tensioner.

5. A traction machine tension control system according to claim 3, characterized in that... The traction machine is a tracked traction machine, which includes a tracked traction machine frame (31). The tracked traction machine frame (31) is provided with a track drive wheel (32), a track driven wheel (33), and a track (34) between the track drive wheel (32) and the track driven wheel (33). The track drive wheel (32), the track driven wheel (33), and the track (34) are set as two sets, upper and lower, and the upper and lower wheels rotate synchronously in opposite directions through meshing gears. The track drive wheel (32) is equipped with a track drive motor, and the track driven wheel (33) is equipped with a tension control system.

6. A traction machine tension control system according to claim 3, characterized in that... The traction machine is a dual-drive belt traction machine. The dual-drive belt traction machine includes a dual-drive belt traction machine frame (41), an inner belt traction device, and an outer belt traction device. The inner belt traction device includes an inner belt drive wheel (431), an inner belt driven wheel (432), a center wheel (42), and an arc-shaped roller (433) arranged sequentially on the dual-drive belt traction machine frame (41). The arc-shaped roller (433) is arranged around the center wheel (42). An inner belt (46) is installed on (433). The outer belt traction device includes an outer belt drive wheel (451), a first outer belt passive wheel (452), a second outer belt passive wheel (453), and a fourth outer belt passive wheel (454) set on the frame (41) of the dual-drive belt traction machine. An outer belt (44) is installed on the outer belt drive wheel (451) and the passive wheel. A dual-drive belt traction machine drive motor is set on both the outer belt drive wheel (451) and the inner belt drive wheel (431). A tension control system is installed on the first outer belt passive wheel (452).

7. A traction machine tension control system according to claim 6, characterized in that... The dual-drive belt traction machine frame (41) is also equipped with a first adjusting cylinder (461) and a second adjusting cylinder (462). The free end of the piston rod of the first adjusting cylinder (461) is connected to the center wheel (42), and the free end of the piston rod of the second adjusting cylinder (462) is connected to the fourth outer belt passive wheel (454). The center wheel (42) and the fourth outer belt passive wheel (454) are slidably connected to the dual-drive belt traction machine frame (41).

8. A traction machine tension control system according to claim 3, characterized in that... The traction machine is a wrapping traction machine. The wrapping traction machine support (51) is equipped with a wrapping traction machine center wheel (52) and a wrapping traction device. The wrapping traction device includes a first wrapping drive wheel (53), a second wrapping driven wheel (54), a third wrapping driven wheel (55), a fourth wrapping driven wheel (56), and an outer wrapping belt (57). The wrapping traction machine center wheel (52) is equipped with an inner wrapping belt. The wrapping traction machine outer wrapping belt (57) is equipped on the driven wheel. The driven wheel is located around the wrapping traction machine center wheel (52). Both the wrapping traction machine center wheel (52) and the first wrapping drive wheel (53) are equipped with wrapping drive motors. The fourth wrapping driven wheel (56) is equipped with a tension control system.

9. A traction machine tension control system according to claim 8, characterized in that... The tape traction machine bracket (51) is provided with a slide rail, the second tape driven wheel (54) is slidably connected to the slide rail, the cylinder body of the tape tensioning cylinder is connected to the tape traction machine bracket (51), and the free end of its piston rod is connected to the second tape driven wheel (54).

10. A three-layer co-extrusion dry crosslinking production line, characterized in that... The system includes a wire feeding machine (61), a wire storage device (62), a traction machine as described in any one of claims 1 to 9 as an upper traction machine (63), three extruders, a three-layer co-extrusion die head (64), a seal (65), a cross-linking pipeline, a heating pipeline (67), a pre-cooling pipeline (68), a cooling pipeline (69), a lower traction machine (66), and a take-up machine. The upper traction machine (63) is connected to a counter-tension control system, and the lower traction machine (66) is connected to a positive tension control system.

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