Synchronous lead screw automatic tensioning device with buffering function and method

Abstract

The invention provides a synchronous lead screw automatic tensioning device and method with a buffering function, and relates to the technical field of belt conveyor tensioning equipment. According to the synchronous lead screw automatic tensioning device and method with the buffering function, variable-frequency driving, synchronous lead screw transmission and hydraulic buffering are combined, rapid and accurate tensioning force adjustment is provided for a belt conveyor under the normal working condition, the rope tensioning and rope loosening speed is high, the tensioning force adjustment response speed is high, and the safety of the belt conveyor is guaranteed. Stable operation of the belt conveyor under the normal working condition is guaranteed, rapid and accurate adjustment of the tensioning force can be achieved in the starting stage and the emergency shutdown working condition of the conveyor, instantaneous impact caused by fluctuation of the tension of the rubber belt is absorbed through hydraulic buffering, impact of the peak tension of the rubber belt on mechanical parts is reduced, the tensioning rope is short and not prone to being broken, and the service life of the belt conveyor is prolonged. Safe starting and stopping of the belt conveyor are achieved, the service life of the belt conveyor is prolonged, and the automatic tensioning device is particularly suitable for automatic tensioning of the long-distance belt conveyor.

Description

Technical Field

[0001] The present invention relates to the technical field of belt conveyor tensioning equipment, in particular to an automatic tensioning device and method for a synchronous screw with a buffering function. Background Art

[0002] The tensioning device is one of the key components of the belt conveyor. It provides sufficient tension for the belt conveyor to prevent slipping between the belt and the roller, and plays an important role in ensuring the reliable operation of the belt conveyor.

[0003] Due to the elasticity of the belt, belt conveyor tension fluctuates significantly during startup and shutdown, often fluctuating several or even dozens of times in less than a second. This creates dramatic fluctuations and can lead to damaging mechanical shock. This requires the tensioning device to provide stable tension to the belt at all times. When the belt tension is excessive or insufficient, the tensioning device can quickly loosen or tighten the belt to maintain constant tension and reduce shock.

[0004] Existing winch tensioning devices and hydraulic cylinder tensioning devices no longer meet the automation control requirements of long-distance belt conveyors. The former lacks a buffering function and cannot absorb the transient impact caused by belt tension fluctuations. The entire tensioning process relies entirely on tightening or loosening the wire rope, which is long and prone to breakage when subjected to sudden tension fluctuations. Furthermore, the wire rope is wound around the winch drum, and the tensioning or loosening displacement of the wire rope is adjusted by the number of drum rotations, resulting in low response accuracy (tension adjustment accuracy). While the latter has a certain buffering function and can absorb the transient impact caused by belt tension fluctuations to a certain extent, it relies on the expansion and contraction of the hydraulic cylinder to loosen and loosen the rope. The hydraulic cylinder's expansion and contraction is very slow, resulting in slow tensioning and loosening speeds and a slow tension adjustment response speed. Furthermore, the hydraulic cylinder requires a hydraulic station, hydraulic pump, accumulator, and various valves, making it bulky, occupying a large installation space, and high cost. Furthermore, the tensioning cylinder's tensioning stroke is limited, making it unsuitable for long-distance belt conveyors.

[0005] This shows that the tensioning device of the prior art needs to be further improved and enhanced. Summary of the Invention

[0006] The purpose of the present invention is to provide a synchronous screw automatic tensioning device and method with a buffering function to achieve a fast and accurate response of the tensioning force adjustment, and at the same time, have a buffering function to absorb the impact caused by the fluctuation of the tape tension.

[0007] In order to achieve the above objectives, the technical solutions adopted by the present invention are as follows:

[0008] A synchronous screw automatic tensioning device with a buffering function, comprising:

[0009] A roller frame, on which a roller is provided, and the roller is connected with an adhesive tape;

[0010] A guide platform is provided with a hydraulic buffer cylinder, and a telescopic rod of the hydraulic buffer cylinder is connected to the roller frame via a tension rope;

[0011] The lead screw cooperates with the nut on the guide table, and the lead screw rotates to drive the nut and the guide table to move;

[0012] The motor has an output shaft that is connected to the lead screw, and the output shaft rotates to drive the lead screw to rotate;

[0013] A tension sensor is provided on the tension rope to monitor the tension of the tension rope in real time;

[0014] Frequency converter, signal is connected to the control end of the motor;

[0015] The controller is respectively connected to the tension sensor and the frequency converter through signals, and is used to control the frequency converter to output three-phase alternating current of different frequencies to the motor according to the tension of the tension rope, so as to change the speed of the motor.

[0016] Furthermore, the number of the lead screws is two;

[0017] It also includes a synchronous reversing reducer and a deceleration and torque-increasing reducer. The output shaft of the motor is connected to the input end of the synchronous reversing reducer. The two output ends of the synchronous reversing reducer are both connected to the input end of a deceleration and torque-increasing reducer. The output end of each deceleration and torque-increasing reducer is connected to a lead screw.

[0018] Furthermore, the output shaft of the motor is connected to the input end of the synchronous reversing reducer via a coupling, the output end of the synchronous reversing reducer is connected to the input end of the deceleration and torque increasing reducer via a coupling, and the output end of the deceleration and torque increasing reducer is connected to one end of the screw via a coupling.

[0019] Furthermore, the lead screw is symmetrically arranged on both sides of the hydraulic buffer cylinder and the tensioning rope, and the axial direction of the lead screw is arranged parallel to the extending direction of the tensioning rope.

[0020] Furthermore, it also includes a support seat, on which a bearing is provided, and both ends of the lead screw are rotatably connected to the bearing.

[0021] Furthermore, the hydraulic buffer cylinder also includes a cylinder body, a piston and a spring. The cylinder body is arranged on the guide platform, and the cylinder body is filled with hydraulic oil. The piston is fitted into the interior of the cylinder body, and the piston can move along the axial direction of the cylinder body. Several damping holes connecting the rod cavity and the rodless cavity of the cylinder body are opened on the piston, and a spring is connected between the rod cavity of the cylinder body and the piston.

[0022] Furthermore, the spring is configured as a disc spring.

[0023] Furthermore, the tension sensor is configured as a plate-ring type tension sensor.

[0024] A belt conveyor automatic tensioning method, using the above-mentioned synchronous screw automatic tensioning device with a buffering function, the method process is as follows:

[0025] The tension sensor monitors the tensioning force F of the tensioning rope in real time and uploads it to the controller. When the controller determines that Fu ≥ F ≥ Fd, it outputs no command, the motor does not operate, and the guide table does not move. When the controller determines that F > Fu or F < Fd, the controller outputs a command according to the set algorithm, causing the inverter to drive the motor to change the motor speed and control the motor's running time, driving the screw to rotate to move the guide table, and then driving the roller frame to move to change the belt tension and the tensioning force F of the tensioning rope, until the tension F is restored to Fu ≥ F ≥ Fd. Here, Fu is the set upper limit of the tensioning force, and Fd is the set lower limit of the tensioning force.

[0026] at the same time,

[0027] When the belt tension fluctuates, the piston is driven to move along the axial direction of the cylinder body through the tensioning rope and the telescopic rod. The piston moves along the axial direction of the cylinder body to compress the spring or reset the spring. The hydraulic oil flows between the rod cavity and the rodless cavity through the damping hole to absorb the instantaneous impact caused by the belt tension fluctuation.

[0028] Further, the controller outputs instructions according to a proportional-integral-derivative control algorithm;

[0029] When the controller determines that F>Fu or F<Fd, the controller determines the difference △F between the tensioning force F of the tensioning rope and the set tension; when the controller determines that △F is greater than or equal to the set value, the controller outputs an instruction to make the frequency converter output three-phase alternating current of the set high frequency segment to the motor, so that the motor outputs the speed of the set high speed segment, and the guide platform moves at the speed of the set high speed segment; when the controller determines that △F is less than the set value, the controller outputs an instruction to make the frequency converter output three-phase alternating current of the set low frequency segment to the motor, so that the motor outputs the speed of the set low speed segment, and the guide platform moves at the speed of the set low speed segment; wherein, the frequency of the set high frequency segment is greater than the frequency of the set low frequency segment, the speed of the set high speed segment is greater than the speed of the set low speed segment, and the speed of the set high speed segment is greater than the speed of the set low speed segment.

[0030] Beneficial technical effects of the present invention:

[0031] The synchronous screw automatic tensioning device and method with a buffering function of the present invention combines frequency conversion drive, synchronous screw transmission and hydraulic buffering to provide fast and accurate tensioning force adjustment for the belt conveyor under normal working conditions. The rope tightening and loosening speeds are very fast, and the tensioning force adjustment response speed is fast, ensuring the stable operation of the belt conveyor under normal working conditions. It can also achieve fast and accurate adjustment of the tensioning force during the conveyor starting stage and emergency shutdown conditions, and absorb the instantaneous impact caused by the belt tension fluctuation through hydraulic buffering, reducing the impact of the belt peak tension on mechanical components. The tensioning rope is short and not easy to break, thereby achieving safe starting and stopping of the belt conveyor and extending the service life of the belt conveyor. It is particularly suitable for automatic tensioning of long-distance belt conveyors. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic structural diagram of a synchronous screw automatic tensioning device with a buffering function according to an embodiment of the present invention;

[0033] Figure 2 This is a schematic structural diagram of a hydraulic buffer cylinder according to an embodiment of the present invention;

[0034] Figure 3 A side view of a guide platform according to an embodiment of the present invention;

[0035] Figure 4 This is a schematic structural diagram of the lead screw, nut and other components of an embodiment of the present invention;

[0036] Figure 5 This is a structural diagram of a synchronous reversing reducer according to an embodiment of the present invention;

[0037] Figure 6 This is a schematic structural diagram of a tension sensor according to an embodiment of the present invention;

[0038] Reference numerals:

[0039] 1. Roller frame, 11. Roller, 12. Tape, 2. Guide platform, 21. Telescopic rod, 22. Cylinder body, 221. Assembly bolt, 23. Piston, 231. Damping hole, 24. Spring, 25. Hydraulic oil, 31. Screw, 32. Nut, 4. Electric motor, 401. First coupling, 402. Second coupling, 403. Third coupling, 41. Synchronous reversing reducer, 42. Speed reduction and torque increase reducer, 43. Support seat, 5. Tension sensor, 6. Frequency converter, 7. Controller, 8. Tension rope, 9. Signal cable. DETAILED DESCRIPTION

[0040] To make the objectives, technical solutions, and beneficial effects of the present invention more clearly understood, the present invention is further described below in conjunction with specific embodiments and with reference to the accompanying drawings. Certain embodiments of the present invention will be more fully described below with reference to the accompanying drawings, some, but not all, of which are illustrated. The various embodiments of the present invention may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present invention satisfies applicable legal requirements.

[0041] In the description of the present invention, it should be noted that the terms "inner," "outer," "upper," "lower," "front," and "rear," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] In an embodiment of the present invention, a synchronous screw automatic tensioning device and method with a buffer function is provided. Please refer to Figures 1 to 6 shown.

[0043] A synchronous screw automatic tensioning device with a buffering function comprises a roller frame 1, a guide platform 2, a screw 31, a motor 4, a tension sensor 5, a frequency converter 6 and a controller 7.

[0044] A roller 11 is provided on the roller frame 1, and the roller 11 is connected to a belt 12. During the operation of the belt conveyor, the roller 11 rotates relative to the roller frame 1, and the belt 12 moves to drive the material thereon to move, thereby realizing the conveying of the material.

[0045] A hydraulic buffer cylinder is provided on the guide platform 2, and a telescopic rod 21 of the hydraulic buffer cylinder is connected to the drum frame 1 via a tensioning rope 8. The tensioning rope 8 is provided as a steel wire rope, and the tension sensor 5 is a plate-ring type tension sensor, which is provided on the tensioning rope 8 for real-time monitoring of the tensioning force of the tensioning rope 8.

[0046] The lead screw 31 cooperates with the nut 32 on the guide platform 2 , and the lead screw 31 rotates to drive the nut 32 and the guide platform 2 to move along the axial direction of the lead screw 31 .

[0047] The output shaft of the motor 4 is connected to the lead screw 31 in a transmission manner. The output shaft of the motor 4 rotates to drive the lead screw 31 to rotate.

[0048] Two lead screws 31 are provided. The output shaft of the motor 4 is connected to the input of a synchronous reversing reducer 41 via a first coupling 401. Both output ends of the synchronous reversing reducer 41 are connected to the input of a torque-reducing reducer 42 via a second coupling 402. The output end of each torque-reducing reducer 42 is connected to one end of a lead screw 31 via a third coupling 403. Bearings are provided on the support base 43. The ends of the lead screw 31 are rotatably connected to the bearings, allowing the lead screw 31 to rotate relative to the support base 43.

[0049] The output shaft of the motor 4 rotates, and drives the input end of the synchronous reversing reducer 41 to rotate through the first coupling 401. The input end of the synchronous reversing reducer 41 drives the two output ends of the synchronous reversing reducer 41 to rotate synchronously, and then drives the two lead screws 31 to rotate synchronously through the deceleration and torque-increasing reducer 42, so that the two sides of the guide platform 2 move synchronously, and then drive the hydraulic buffer cylinder and the tensioning rope 8 to move along the same axis. The movement process does not deflect, and the tensioning rope 8 maintains the traction direction of the tensioning force on the belt 12.

[0050] The motor 4 transmits power to two parallel arranged screws 31 through a synchronous reversing reducer 41 and a deceleration and torque increasing reducer 42. The transmission ratio between the output shaft of the motor 4 and the screw 31 is precise and the transmission efficiency is high, thereby making the moving speed and displacement of the guide platform 2 precise, and the moving speed can be adjusted quickly, so that the moving speed and displacement of the hydraulic buffer cylinder and the tensioning rope 8 (tightening the rope, loosening the rope) are precise, and the moving speed is switched quickly, thereby realizing fast and precise adjustment of the tensioning force of the belt 12.

[0051] The travel of guide platform 2 is the tensioning travel. This travel is achieved by rotating the lead screw 31, which drives the nut 32 and guide platform 2 along the axial direction of the lead screw 31. The lead screw 31 can rotate rapidly, driving the nut 32 and guide platform 2 to move quickly, allowing for rapid rope tightening and loosening as needed. The tensioning force is precisely adjusted by the distance the nut 32 moves relative to the lead screw 31, resulting in high adjustment accuracy.

[0052] The inverter 6 is connected to the control terminal of the motor 4 via a signal cable 9. The controller 7 is also connected to the tension sensor 5 and the inverter 6 via the signal cable 9. The controller 7 is used to control the inverter 6 to output three-phase AC power of different frequencies to the motor 4 according to the real-time tension of the tension rope 8, thereby changing the speed of the motor 4 in real time.

[0053] The tension sensor 5 monitors the tension of the tension rope 8 in real time and uploads it to the controller 7. The controller 7 controls the frequency converter 6 to drive the motor 4 to change the speed (including the speed and rotation direction) of the motor 4 according to the real-time tension of the tension rope 8, and controls the running time of the motor 4. The frequency converter 6 outputs three-phase AC power of a set frequency to the motor 4, so that the motor 4 outputs a set speed, drives the screw 31 to rotate, and moves the guide platform 2 at a set speed, so that the guide platform 2 moves to a set position at a set speed, and then drives the roller frame 1 to move to change the tension of the tape 12 and the tension of the tension rope 8.

[0054] The lead screw 31 is axially symmetrically arranged on either side of the hydraulic buffer cylinder and the tensioning rope 8, with the axial direction of the lead screw 31 parallel to the extension direction of the tensioning rope 8. This arrangement allows the lead screw 31 to be arranged on both sides of the belt conveyor, allowing the lead screw 31 to be set to a longer length. This allows the nut 32 to move along the lead screw 31 over a longer range, resulting in a longer tensioning stroke, suitable for the tensioning requirements of long-distance belt conveyors.

[0055] The hydraulic buffer cylinder also includes a cylinder body 22, a piston 23 and a spring 24. One end of the cylinder body 22 is connected to the guide platform 2 via an assembly bolt 221. The cylinder body 22 is filled with hydraulic oil 25. The piston 23 fits inside the cylinder body 22. The piston 23 can move along the axial direction of the cylinder body 22. Several damping holes 231 are opened on the piston 23. The damping holes 231 connect the rod cavity and the rodless cavity of the cylinder body 22. The spring 24 is connected between the rod cavity of the cylinder body 22 and the piston 23. The spring 24 is configured as a disc spring.

[0056] It should be noted that the hydraulic buffer cylinder only requires that the cylinder body 22 be filled with hydraulic oil 25 before operation. Unlike ordinary hydraulic cylinders, the cylinder body 22 does not need to be continuously filled with and discharged hydraulic oil during operation. The hydraulic buffer cylinder also does not require a hydraulic station, hydraulic pump, accumulator, various valves, etc.

[0057] When the tension of the adhesive tape 12 fluctuates and creates a transient impact, the tension acts on the telescopic rod 21 via the roller 11, roller frame 1, and tensioning rope 8. The telescopic rod 21 drives the piston 23 to reciprocate relative to the cylinder 22. During the reciprocating movement of the piston 23 relative to the cylinder 22, the spring 24 is repeatedly compressed and reset. Simultaneously, the piston 23 squeezes the hydraulic oil in the rod chamber or the rodless chamber. The hydraulic oil 25 flows from the rod chamber of the cylinder 22 through the damping hole 231 in the piston 23 into the rodless chamber of the cylinder 22. Alternatively, the hydraulic oil 25 flows from the rodless chamber of the cylinder 22 through the damping hole 231 in the piston 23 into the rod chamber of the cylinder 22. Specifically, when the piston 23 moves outward relative to the cylinder body 22, the spring 24 is compressed, and the hydraulic oil 25 flows from the rod chamber of the cylinder body 22 through the damping hole 231 on the piston 23 into the rodless chamber of the cylinder body 22; when the piston 23 moves inward relative to the cylinder body 22, the spring 24 is reset, and the hydraulic oil 25 flows from the rodless chamber of the cylinder body 22 through the damping hole 231 on the piston 23 into the rod chamber of the cylinder body 22.

[0058] Spring 24 is repeatedly compressed and reset, absorbing the energy of transient impacts and enabling piston 23 to reciprocate within cylinder 22, gradually damping the impact. Hydraulic oil 25 flows between the rod chamber and rodless chamber of cylinder 22 through damping orifice 231, also absorbing the energy of transient impacts and extending the compression and reset cycle of spring 24. This provides smoother and more flexible cushioning of transient impacts and prevents frequent side-to-side oscillation of telescopic rod 21. Depending on the required conveyor tensioning stroke, a longer tensioning stroke can be achieved by increasing the number of springs 24 and lengthening cylinder 22.

[0059] A belt conveyor automatic tensioning method is provided, which uses the synchronous screw automatic tensioning device with a buffering function described above in this embodiment. The method process is as follows:

[0060] The tension sensor 5 monitors the tensioning force F of the tensioning rope 8 in real time and uploads it to the controller 7; when the controller 7 determines that Fu≥F≥Fd, the controller 7 has no command output, the motor 4 does not operate, and the guide platform 2 does not move; when the controller 7 determines that F>Fu or F<Fd, the controller 7 outputs a command according to the set algorithm, causing the frequency converter 6 to drive the motor 4 to change the speed of the motor 4, and controls the running time of the motor 4, driving the screw 31 to rotate to move the guide platform 2, and then driving the roller frame 1 to move to change the tension of the tape 12 and the tensioning force F of the tensioning rope 8, until the tensioning force F is restored to Fu≥F≥Fd; wherein Fu is the set upper limit value of the tensioning force, Fu is 1.05Fe, Fd is the set lower limit value of the tensioning force, Fd is 0.95Fe, and Fe is the rated tension;

[0061] at the same time,

[0062] When the tension of the tape 12 fluctuates, the piston 23 is driven to move axially along the cylinder body 22 through the tensioning rope 8 and the telescopic rod 21. The piston 23 moves axially along the cylinder body 22 to compress or reset the spring 24. The hydraulic oil 25 flows between the rod cavity and the rodless cavity through the damping hole 231 to absorb the instantaneous impact caused by the tension fluctuation of the tape 12.

[0063] On this basis, the controller outputs instructions according to the proportional-integral-derivative control algorithm;

[0064] When the controller 7 determines that F>Fu or F<Fd, the controller 7 determines the difference ΔF between the tensioning force F of the tensioning rope 8 and the set tension; when the controller 7 determines that ΔF is greater than or equal to the set value, the controller 7 outputs an instruction to cause the frequency converter 6 to output three-phase AC power of the set high frequency range to the motor 4, causing the motor 4 to output a speed of the set high speed range, and the guide platform 2 moves at the speed of the set high speed range, and the guide platform 2 moves quickly to quickly adjust the tension;

[0065] When the controller 7 determines that ΔF is less than the set value, the controller 7 outputs a command to make the inverter 6 output three-phase AC power of the set low frequency range to the motor 4, so that the motor 4 outputs the speed of the set low speed range, and the guide table 2 moves at the speed of the set low speed range. The guide table 2 moves slowly and the tensioning force is accurately adjusted;

[0066] The frequency of the high frequency segment is set to be greater than the frequency of the low frequency segment, the speed of the high speed segment is set to be greater than the speed of the low speed segment, and the speed of the high speed segment is set to be greater than the speed of the low speed segment.

[0067] So far, this embodiment has been described in detail with reference to the accompanying drawings. Based on the above description, those skilled in the art should have a clear understanding of the synchronous screw automatic tensioning device and method with a buffering function of the present invention. The synchronous screw automatic tensioning device and method with a buffering function of the present invention combine variable frequency drive, synchronous screw transmission and hydraulic buffering to provide fast and accurate tensioning force adjustment for the belt conveyor under normal working conditions. The rope tightening and loosening speeds are very fast, and the tensioning force adjustment response speed is fast, ensuring the stable operation of the belt conveyor under normal working conditions. It can also achieve fast and accurate adjustment of the tensioning force during the conveyor start-up phase and emergency shutdown conditions, and absorb the instantaneous impact caused by the tension fluctuation of the belt 12 through hydraulic buffering, reducing the impact of the peak tension of the belt 12 on the mechanical components. The tensioning rope 8 is short and not easy to break, thereby achieving safe starting and stopping of the belt conveyor and extending the service life of the belt conveyor. It is particularly suitable for automatic tensioning of long-distance belt conveyors.

[0068] Of course, the specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A synchronous screw automatic tensioning device with a buffer function, characterized in that: include: A roller frame, on which a roller is provided, and the roller is connected with an adhesive tape; A guide platform is provided with a hydraulic buffer cylinder, and a telescopic rod of the hydraulic buffer cylinder is connected to the roller frame via a tension rope; The lead screw cooperates with the nut on the guide table, and the lead screw rotates to drive the nut and the guide table to move; The motor has an output shaft that is connected to the lead screw, and the output shaft rotates to drive the lead screw to rotate; A tension sensor is provided on the tension rope to monitor the tension of the tension rope in real time; Frequency converter, signal is connected to the control end of the motor; The controller is respectively connected to the tension sensor and the frequency converter through signals, and is used to control the frequency converter to output three-phase alternating current of different frequencies to the motor according to the tension of the tension rope, so as to change the speed of the motor.

2. The automatic tensioning device for a synchronous screw with a buffering function according to claim 1, characterized in that: The number of the lead screws is two; It also includes a synchronous reversing reducer and a deceleration and torque-increasing reducer. The output shaft of the motor is connected to the input end of the synchronous reversing reducer. The two output ends of the synchronous reversing reducer are both connected to the input end of a deceleration and torque-increasing reducer. The output end of each deceleration and torque-increasing reducer is connected to a lead screw.

3. The automatic tensioning device for synchronous screw with buffer function according to claim 2, characterized in that: The output shaft of the motor is connected to the input end of the synchronous reversing reducer through a coupling, the output end of the synchronous reversing reducer is connected to the input end of the deceleration and torque increasing reducer through a coupling, and the output end of the deceleration and torque increasing reducer is connected to one end of the screw through a coupling.

4. The automatic tensioning device for synchronous screw with buffer function according to claim 2, characterized in that: The lead screw is symmetrically arranged on both sides of the hydraulic buffer cylinder and the tensioning rope, and the axial direction of the lead screw is arranged parallel to the stretching direction of the tensioning rope.

5. The automatic tensioning device for synchronous screw with buffer function according to claim 1, characterized in that: It also includes a support seat, on which a bearing is provided, and both ends of the lead screw are rotatably connected to the bearing.

6. The automatic tensioning device for synchronous screw with buffer function according to claim 1, characterized in that: The hydraulic buffer cylinder also includes a cylinder body, a piston and a spring. The cylinder body is arranged on the guide platform. The cylinder body is filled with hydraulic oil. The piston is fitted into the interior of the cylinder body. The piston can move along the axial direction of the cylinder body. Several damping holes connecting the rod cavity and the rodless cavity of the cylinder body are opened on the piston. A spring is connected between the rod cavity of the cylinder body and the piston.

7. The automatic tensioning device for synchronous screw with buffer function according to claim 6, characterized in that: The spring is configured as a disc spring.

8. The automatic tensioning device for synchronous screw with buffer function according to claim 1, characterized in that: The tension sensor is configured as a plate-ring type tension sensor.

9. A belt conveyor automatic tensioning method, using the synchronous screw automatic tensioning device with buffering function according to any one of claims 1 to 8, characterized in that: The method process is as follows: The tension sensor monitors the tensioning force F of the tensioning rope in real time and uploads it to the controller. When the controller determines that Fu ≥ F ≥ Fd, it outputs no command, the motor does not operate, and the guide table does not move. When the controller determines that F > Fu or F < Fd, the controller outputs a command according to the set algorithm, causing the inverter to drive the motor to change the motor speed and control the motor's running time, driving the screw to rotate to move the guide table, and then driving the roller frame to move to change the belt tension and the tensioning force F of the tensioning rope, until the tension F is restored to Fu ≥ F ≥ Fd. Here, Fu is the set upper limit of the tensioning force, and Fd is the set lower limit of the tensioning force. at the same time, When the belt tension fluctuates, the piston is driven to move along the axial direction of the cylinder body through the tensioning rope and the telescopic rod. The piston moves along the axial direction of the cylinder body to compress the spring or reset the spring. The hydraulic oil flows between the rod cavity and the rodless cavity through the damping hole to absorb the instantaneous impact caused by the belt tension fluctuation.

10. The automatic tensioning method for a belt conveyor according to claim 9, characterized in that: The controller outputs instructions according to the proportional-integral-derivative control algorithm; When the controller determines that F>Fu or F<Fd, the controller determines the difference △F between the tensioning force F of the tensioning rope and the set tension; when the controller determines that △F is greater than or equal to the set value, the controller outputs an instruction to make the frequency converter output three-phase alternating current of the set high frequency segment to the motor, so that the motor outputs the speed of the set high speed segment, and the guide platform moves at the speed of the set high speed segment; when the controller determines that △F is less than the set value, the controller outputs an instruction to make the frequency converter output three-phase alternating current of the set low frequency segment to the motor, so that the motor outputs the speed of the set low speed segment, and the guide platform moves at the speed of the set low speed segment; wherein, the frequency of the set high frequency segment is greater than the frequency of the set low frequency segment, the speed of the set high speed segment is greater than the speed of the set low speed segment, and the speed of the set high speed segment is greater than the speed of the set low speed segment.

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