Aluminum core outer layer PVC continuous extrusion coating forming equipment and method thereof

Abstract

The present application relates to the field of cable manufacturing and continuous extrusion molding, in particular to a continuous extrusion coating molding equipment for PVC outer layer of aluminum core and a method thereof; the equipment comprises a driving unwinding motor, an asymmetric lever with a guide wheel and a planar spiral spring, a claw coupling with a gap, an absolute value rotary encoder, an extrusion coating die and a programmable logic controller; the equipment senses the aluminum core posture through the asymmetric lever, collects the angle by the absolute value rotary encoder through the claw coupling with the gap and submits the angle to the controller for smooth processing; the preset safe angle interval is used as the speed regulation determination condition, when the angle exceeds the limit, the aluminum core vertical displacement deviation is calculated according to the length of the short arm of the lever and the angle, and the rotating speed of the driving unwinding motor is dynamically regulated and controlled; the equipment isolates the slight disturbance through the mechanical gap of the coupling, combines the control algorithm to shield the normal slight fluctuation, avoids the system oscillation caused by the frequent speed regulation of the motor, and effectively solves the problem of coating eccentricity caused by the aluminum core posture fluctuation before entering the die.

Description

Technical Field

[0001] This invention relates to the field of cable manufacturing and continuous extrusion molding, specifically to a continuous extrusion molding equipment and method for aluminum core with PVC outer layer. Background Technology

[0002] In continuous extrusion coating molding, the skeleton material, such as the aluminum core, needs to be unwound, guided, and continuously fed into the extrusion coating die for the outer PVC layer molding. During this feeding and coating process, high-frequency mechanical disturbances are generated due to factors such as the operation of the traction system gears, the periodic operation of the extruder body, and ground vibration. To control the feeding state, existing solutions generally adopt a constant speed unwinding control architecture, that is, the unwinding roller is driven to release the skeleton material through a preset fixed speed. Although this control scheme has basic feeding capabilities in a static ideal scenario, it lacks a real-time perception and adaptive adjustment mechanism for the actual micro-tension drift of the aluminum core. It is easy to misjudge the high-frequency mechanical disturbance noise as the actual tension change, causing frequent speed adjustments of the unwinding motor and resulting in system oscillation. This approach is difficult to effectively suppress the attitude fluctuations of the aluminum core before entering the die, ultimately leading to obvious periodic uneven wall thickness of the PVC coating layer after extrusion molding.

[0003] Therefore, how to accurately sense and compensate for the tension deviation of the aluminum core in real time while isolating high-frequency mechanical disturbances in the isolation system, thereby improving the stability of the mold insertion posture and effectively solving the problem of eccentric wrapping, has become an urgent technical problem to be solved. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A continuous extrusion coating molding machine for an aluminum core with an outer PVC layer includes: The main frame is sequentially fixed along the aluminum core conveying direction to a front unwinding support, a lever mechanism mounting base, a die head mounting platform, and a rear traction base; an active unwinding motor is fixed to the front unwinding support and drives the unwinding roller supported thereon to rotate; an adjustable bracket is fixed to the lever mechanism mounting base, on which a lever hinge shaft is rotatably connected and fixed to an asymmetrical lever. The asymmetric lever consists of a short arm and a long arm. The end of the short arm is rotatably connected to a guide wheel, and the end of the long arm is fixedly connected to a planar spiral spring that provides the initial return torque. An absolute rotary encoder is coaxially connected to the end of the lever's hinge shaft via a gapped claw coupling to collect angle values. An extrusion coating die is fixedly connected to the die mounting platform and contains an aluminum core passageway and a PVC melt flow channel. The programmable logic controller (PLC) is electrically connected to the active unwinding motor and the absolute rotary encoder. It pre-stores a safe angle range, a reference unwinding linear speed, and short arm length parameters. Its configuration is as follows: smooth the collected angle values; if the value is within the range, maintain the active unwinding motor speed unchanged; if it exceeds the range, calculate the vertical linear displacement deviation of the aluminum core based on the length parameter and the value, calculate the target linear speed accordingly, and control the operation of the active unwinding motor.

[0005] In one alternative, the gapped claw coupling is a three-jaw staggered fit structure, including a driving claw disk and a driven claw disk. The driving claw disk is fixed to the lever hinge shaft, the absolute rotary encoder includes an input shaft of the absolute rotary encoder, and the driven claw disk is fixed to the input shaft of the absolute rotary encoder. A mechanical gap is reserved in the circumferential direction between the protruding claw of the active claw disk and the groove of the driven claw disk. When the swing angle of the lever hinge shaft is less than or equal to the mechanical clearance, the active claw disk rotates freely within the mechanical clearance; When the swing angle of the lever hinge shaft exceeds the mechanical clearance, the active claw plate engages with the driven claw plate.

[0006] In one alternative, the outer circumference of the guide wheel is machined with a semi-circular guide groove that matches the outer diameter of the aluminum core; The outer end of the planar spiral hairspring is fixed to the long arm, and the inner end of the planar spiral hairspring is fixed to the adjustable bracket.

[0007] In one alternative, the programmable logic controller is configured as follows: A data buffer queue with a fixed period is established, and the average of multiple continuously collected angle values ​​is calculated to obtain the smoothed angle value.

[0008] In one alternative, the process of calculating the linear displacement deviation and the target linear velocity includes: determining the linear displacement deviation based on the smoothed angle value and the short arm length parameter; performing proportional and integral compensation calculations based on the linear displacement deviation to obtain a speed compensation value; and superimposing the speed compensation value onto the reference unwinding linear velocity to obtain the target linear velocity.

[0009] In one alternative, the top of the lever mechanism mounting base is horizontally machined with a threaded hole, and the adjustable bracket includes a base plate and a side wall of the adjustable bracket. The base plate of the adjustable bracket is machined with an elongated hole, and bolts pass through the elongated hole to fix the adjustable bracket to the lever mechanism mounting base. The top of the adjustable bracket is rotatably connected to the lever hinge shaft via an angular contact ball bearing, and the housing of the absolute rotary encoder is fixedly connected to the side wall of the adjustable bracket via an L-shaped bracket.

[0010] In one alternative, the active unwinding motor includes an output shaft, which is connected to the unwinding roll via a quincunx flexible coupling. The tail end of the extrusion coating die is connected to the main barrel of the twin-screw extruder, and the PVC melt flow channel is connected to the main barrel of the twin-screw extruder.

[0011] A control method for a continuous extrusion coating molding equipment for an aluminum core with an outer PVC layer includes: S1: When the aluminum core is statically tensioned and the asymmetric lever is in a horizontal reference position, set the current angle value output by the absolute rotary encoder to the zero angle position, and set the short arm length parameter, the safe angle range, and the reference unwinding speed in the programmable logic controller. S2: The active unwinding motor drives the unwinding roller to rotate and release the aluminum core. After being guided by the guide wheel, the aluminum core enters the extrusion coating die head. When the tension of the aluminum core changes, causing the asymmetric lever to generate an angular displacement around the lever hinge axis, and the angular displacement exceeds the mechanical clearance of the claw coupling with clearance, the absolute value rotary encoder outputs an angle value. S3: The programmable logic controller performs a smoothing operation on the continuously collected angle values ​​to obtain a smoothed angle value, and compares the smoothed angle value with the safe angle range; if the smoothed angle value is less than or equal to the upper limit of the safe angle range and greater than or equal to the lower limit of the safe angle range, the current active unwinding motor speed is maintained unchanged; if the smoothed angle value is greater than the upper limit of the safe angle range or less than the lower limit of the safe angle range, the speed compensation calculation process is triggered. S4: The programmable logic controller calculates the linear displacement deviation of the aluminum core in the vertical direction based on the smoothed angle value and the short arm length parameter, and calculates the target linear velocity of the active unwinding motor based on the linear displacement deviation. S5: The active unwinding motor runs at the target linear speed, changing the supply amount at the front end of the aluminum core; when the asymmetric lever retracts to the mechanical clearance range of the claw coupling with gap under the return torque of the planar spiral spring, the programmable logic controller stops adding speed compensation.

[0012] The beneficial effects of this invention are as follows: 1. This invention effectively solves the problem of coating eccentricity caused by aluminum core posture fluctuations before entering the die by using an asymmetrical lever, a claw coupling with clearance, and a programmable logic controller in synergy. The mechanical clearance of the claw coupling with clearance can isolate minor mechanical disturbances in advance. The controller further smooths the collected angle values ​​and uses a safe angle range as a precondition for speed adjustment, effectively shielding normal micro-fluctuations and avoiding system oscillations caused by frequent speed adjustments of the active unwinding motor. This improves the posture stability of the aluminum core when entering the extrusion coating die and the consistency of the coating layer thickness. 2. This invention utilizes a programmable logic controller (PLC) to accurately convert the angle into a vertical linear displacement deviation based on the short arm length parameter when the smoothed angle value exceeds the safe range. The PLC then calculates the target linear speed to control the active unwinding motor. By superimposing the proportional compensation value and integral compensation value derived from the linear displacement deviation onto the reference unwinding linear speed, it can quickly respond to sudden tension changes and continuously converge and eliminate errors caused by long-term material supply imbalance, precisely correcting the material supply speed and ensuring constant tension when the aluminum core enters the die. Attached Figure Description

[0013] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0014] Figure 1 This is a schematic diagram of the overall external structure of the device; Figure 2 This is a structural diagram of the front unwinding support base; Figure 3 This is a schematic diagram of the structure of the lever mechanism mounting base; Figure 4 This is a schematic diagram of the lever hinge shaft; Figure 5 This is a schematic diagram of the extrusion coating die head; Figure 6 A flowchart illustrating the steps of the control method provided in this application embodiment.

[0015] In the diagram: 1. Main frame; 2. Front unwinding support; 3. Lever mechanism mounting base; 4. Die head mounting platform; 5. Rear traction base; 6. Active unwinding motor; 7. Unwinding roller; 8. Adjustable bracket; 9. Lever hinge shaft; 10. Asymmetric lever; 11. Guide wheel; 12. Planar spiral hairspring; 13. Claw coupling with clearance; 14. Absolute rotary encoder; 15. Extrusion coating die head; 16. Short arm; 17. Long arm; 18. Aluminum core passageway; 19. 10. PVC melt flow channel; 21. Active claw disc; 22. Driven claw disc; 23. Protruding claw; 24. Groove; 25. Semi-circular guide groove; 26. Threaded hole; 27. Oblong hole; 28. Bolt; 29. ​​Angular contact ball bearing; 30. L-shaped bracket; 31. Output shaft of active unwinding motor; 32. Plum blossom-shaped flexible coupling; 33. Main barrel of twin-screw extruder; 34. Input shaft of absolute rotary encoder; 35. Base plate of adjustable bracket; 36. Side wall of adjustable bracket. Detailed Implementation

[0016] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. Furthermore, the accompanying drawings of the present invention are for simple illustrative purposes only and are not depictions of actual dimensions; this is stated beforehand. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of protection of the present invention.

[0017] Example 1: Combination Figure 1 A continuous extrusion coating molding equipment for an aluminum core with an outer PVC layer, comprising: The main frame 1 is sequentially fixed along the aluminum core conveying direction to the front unwinding support 2, the lever mechanism mounting base 3, the die head mounting platform 4, and the rear traction base 5; the active unwinding motor 6 is fixed to the front unwinding support 2 and drives the unwinding roller 7 supported on it to rotate; the adjustable bracket 8 is fixed to the lever mechanism mounting base 3, and the lever hinge shaft 9 rotatably connected on it is fixed to the asymmetric lever 10. The asymmetric lever 10 includes a short arm 16 and a long arm 17. The end of the short arm 16 is rotatably connected to a guide wheel 11, and the end of the long arm 17 is fixedly connected to a planar spiral hairspring 12 that provides initial return torque. An absolute rotary encoder 14 is coaxially connected to the end of the lever hinge shaft 9 via a gapped claw coupling 13 to collect angle values. An extrusion coating die head 15 is fixedly connected to the die head mounting platform 4 and has an aluminum core through channel 18 and a PVC melt flow channel 19 inside. The programmable logic controller (PLC) is electrically connected to the active unwinding motor 6 and the absolute rotary encoder 14. It pre-stores the safety angle range, the reference unwinding linear speed, and the length parameters of the short arm 16. Its configuration is as follows: smooth the collected angle values; if the value is within the range, maintain the speed of the active unwinding motor 6 unchanged; if it exceeds the range, calculate the vertical linear displacement deviation of the aluminum core based on the length parameters and the value, calculate the target linear speed accordingly, and control the operation of the active unwinding motor 6.

[0018] This embodiment provides a molding device for continuous feeding of aluminum cores and forming a continuous PVC coating layer on the outer periphery, which is used to solve the problem of coating eccentricity caused by aluminum core posture fluctuation and micro-tension drift before entering the mold; the device uses the main frame 1 as the bearing base, and arranges the front unwinding support 2, lever mechanism mounting base 3, mold head mounting platform 4 and rear traction base 5 in sequence along the conveying direction, so that the aluminum core forms a continuous conveying path from unwinding, guiding, entering the mold to traction. The active unwinding motor 6 drives the unwinding roller 7 to release the aluminum core. The guide wheel 11 is installed at the end of the short arm 16 of the asymmetric lever 10. The planar spiral hairspring 12 provides a stable initial return torque for the asymmetric lever 10. The gapped claw coupling 13 isolates the small mechanical disturbances of the lever hinge shaft 9 from the sampling end of the absolute value rotary encoder 14. After reading the angle value output by the absolute rotary encoder 14, the programmable logic controller (PLC) performs smoothing processing and uses a pre-stored safe angle range as a judgment benchmark. When the angle value remains within the range, the benchmark unwinding linear speed is maintained. When the angle value exceeds the range, the linear displacement deviation is calculated based on the length parameter of the short arm 16 and the angle value, and the target linear speed of the active unwinding motor 6 is then corrected accordingly. Through this structure and control method, mechanical disturbances are suppressed in advance, the true tension trend is preserved and converted into an executable speed correction amount, thereby improving the posture stability and coating layer thickness consistency when the aluminum core enters the extrusion coating die 15. Among them, the safe angle range represents the range of angle fluctuations that the asymmetric lever 10 is allowed to maintain the current feeding state around the zero angle position. Its physical meaning is the angle zone corresponding to when the aluminum core can still be regarded as being in a stable posture and with acceptable tension deviation before entering the extrusion coating die head 15. The center value of this interval is taken as the zero angle. The upper and lower limits of the interval can be determined based on the angle samples continuously collected during the trial run under stable production conditions: first, after the extruder, traction machine and unwinding mechanism have all entered stable working conditions, record multiple continuous angle samples, then take the upper and lower boundaries of the fluctuation of the stable sample, and add an allowable process margin on this basis as the upper and lower limits of the safe angle interval. The process margin is specifically determined by reverse calculation based on the speed regulation response time of the active unwinding motor 6 and the tolerance requirements of the eccentricity of the PVC coating layer, so as to ensure that the attitude fluctuation within this margin range will not cause the coating layer thickness to exceed the standard error; the role of this safety angle range in the control process is as a logical threshold for whether to start speed compensation. Only when the smoothed angle value exceeds this range will the controller determine that the aluminum core attitude deviation has continued to the point that the feeding speed needs to be corrected. The reference unwinding speed represents the reference feeding speed that the active unwinding motor 6 should maintain when the aluminum core tension is stable and the asymmetric lever 10 is within the safe angle range. Its physical meaning is the balanced speed when the front unwinding amount, the rear traction amount, and the die head wrapping rhythm are matched. This reference unwinding speed can be calibrated by the rear traction speed or the actual speed of the unwinding roller 7 during stable production, and written into the programmable logic controller as the basis value for subsequent speed compensation superposition. When the smoothed angle value is within the safe angle range, the controller does not recalculate the compensation amount, but keeps the current speed running around the reference unwinding speed to avoid over-adjusting normal micro-fluctuations. Among them, the length parameter of the short arm 16 represents the geometric distance from the center of the lever hinge shaft 9 to the center of the guide wheel 11. Its physical meaning is the mechanism size reference used when converting the angle change into the vertical displacement of the guide wheel 11. This parameter can be obtained by physical measurement after the equipment is assembled, or it can be recalibrated and written into the controller after replacing the guide wheel 11 with different specifications or adjusting the installation position of the guide wheel 11. After the controller smooths the angle value output by the absolute rotary encoder 14, it first obtains the smoothed angle value for judgment, and then calls the short arm 16 length parameter to convert the angle value into the vertical displacement deviation of the guide wheel 11. Then the displacement deviation is converted into the target linear velocity. Therefore, the short arm 16 length parameter is the geometric source parameter connecting the angle sampling result and the velocity correction result. Smoothing, interval judgment, displacement conversion, and speed correction are performed in the following order: The controller first receives the original angle value from the absolute rotary encoder 14 as input, and then performs smoothing calculation on the continuous angle samples to reduce instantaneous sampling glitch; then it compares the smoothed angle value with the safe angle interval to determine whether to enter the compensation process; if compensation is required, the angle offset is converted into a linear displacement deviation in the vertical direction based on the length parameter of the short arm 16; the target linear velocity is generated based on the linear displacement deviation and output to the active unwinding motor 6; Thus, a clear data flow relationship is formed between the angle sampling result, the logical threshold judgment, the geometric conversion result, and the motor control output, avoiding the control process from merely remaining at the level of abstract description. Because comparing the smoothed angle value with the safe angle range is used as a logical prerequisite for whether to start speed compensation, it can effectively shield normal micro-tension fluctuations within the allowable range and avoid system oscillations caused by frequent speed adjustments of the active unwinding motor 6. Because the linear displacement deviation is accurately calculated based on geometric parameters only when the range is exceeded, the speed compensation action has clear targeting and appropriateness, ensuring constant tension when the aluminum core enters the extrusion coating die 15, and ultimately controlling the eccentricity of the coating layer within the set tolerance range.

[0019] Combination Figure 4 The gapped claw coupling 13 has a three-jaw staggered fit structure, including a driving claw disk 20 and a driven claw disk 21. The driving claw disk 20 is fixed to the lever hinge shaft 9. The absolute rotary encoder 14 includes an input shaft 33 of the absolute rotary encoder. The driven claw disk 21 is fixed to the input shaft 33 of the absolute rotary encoder. A mechanical clearance is reserved in the circumferential direction between the protruding claw 22 of the active claw disk 20 and the groove 23 of the driven claw disk 21; when the swing angle of the lever hinge shaft 9 is less than or equal to the mechanical clearance, the active claw disk 20 rotates freely within the mechanical clearance; when the swing angle of the lever hinge shaft 9 exceeds the mechanical clearance, the active claw disk 20 and the driven claw disk 21 engage.

[0020] In this embodiment, the gapped claw coupling 13 adopts a three-jaw staggered fit structure. The active claw disk 20 is installed at the end of the lever hinge shaft 9, and the driven claw disk 21 is installed at the end of the input shaft 33 of the absolute rotary encoder. The two achieve torque transmission through the cooperation of the protruding claw 22 and the groove 23. A circumferential mechanical gap is set between the protruding claw 22 and the groove 23, which corresponds to the range of small high-frequency disturbances that the equipment can absorb. When ground vibration, traction system gear disturbance or periodic vibration of the extruder body is transmitted to the lever hinge shaft 9, if the swing angle does not exceed the mechanical clearance, the active claw disk 20 will only rotate relative to each other within the clearance, the input shaft 33 of the absolute value rotary encoder will remain stationary, and the sampling end will not record this type of short-amplitude mechanical noise. If the change in aluminum core tension reaches a level that exceeds the mechanical clearance, the active claw plate 20 and the driven claw plate 21 enter a meshing state, and the swing of the lever hinge shaft 9 is transmitted to the absolute rotary encoder 14 so that the controller can respond to the actual attitude deviation. This structure separates the mechanical disturbance and the effective attitude change, so that the input signal faced by the subsequent smoothing calculation is closer to the actual tension trend.

[0021] The outer circumference of the guide wheel 11 is machined with a semi-circular guide groove 24 that matches the outer diameter of the aluminum core; the outer end of the planar spiral hairspring 12 is fixed to the long arm 17, and the inner end of the planar spiral hairspring 12 is fixed to the adjustable bracket 8.

[0022] In this embodiment, a semi-circular guide groove 24 is provided on the outer circumference of the guide wheel 11. The curved contour of the semi-circular guide groove 24 matches the outer diameter of the aluminum core, so that the aluminum core maintains a limited contact position when guided by the guide wheel 11, and avoids the aluminum core from lateral deviation when the short arm 16 is under force. The outer end of the planar spiral hairspring 12 is fixed to the long arm 17 of the asymmetric lever 10, and the inner end is fixed to the adjustable bracket 8. After installation, the planar spiral hairspring 12 is preset with a return torque to offset the downward bias caused by the weight of the guide wheel 11 and the reference tension of the aluminum core, so that the asymmetric lever 10 maintains a repeatable zero position under static conditions. Since the semi-circular guide groove 24 of the guide wheel 11 defines the contact geometry of the aluminum core and the planar spiral hairspring 12 defines the return torque of the lever, the centerline position of the aluminum core before entering the extrusion coating die head 15 is more stable after the two work together, and the angle change corresponding to the absolute value rotary encoder 14 is also easier to establish a one-to-one correspondence with the tension change.

[0023] The programmable logic controller is configured to: establish a data buffer queue with a fixed period, and perform an average calculation on multiple continuously collected angle values ​​to obtain a smoothed angle value.

[0024] In this embodiment, the programmable logic controller reads the output angle value of the absolute value rotary encoder 14 at a fixed period and establishes a data buffer queue in the storage unit. The buffer queue stores multiple continuously acquired angle samples. After each new angle sample is obtained, the earliest sample that entered the buffer queue is removed, and the latest sample is written to the end of the queue. Then, the arithmetic mean of all angle samples in the queue is calculated to obtain the smoothed angle value. The specific calculation formula is as follows:

[0025] In the formula, This represents the smoothed angle value; This represents the i-th consecutively acquired angle value in the data buffer queue; N represents the number of samples stored in the data buffer queue; ∑ is the summation operator, which means summing up the N consecutively acquired angle values ​​in the data buffer queue; this processing method is suitable for reducing the impact burrs and short-cycle vibrations at the moment of coupling engagement on the judgment result, making the angle value based on the controller more stable. Since the smoothed angle value is directly involved in the safe zone judgment and speed compensation calculation, the buffer queue is not an independent data storage, but constitutes part of the control logic to ensure that the output speed correction action only responds to the persistent attitude offset. The fixed period refers to the sampling time interval between two adjacent readings of the absolute value rotary encoder 14 angle values ​​by the controller. The setting principle is to cover the effective response process of the aluminum core attitude change while avoiding the high-frequency mechanical disturbance amplitude from exceeding the set threshold. In actual applications, the fixed period can be set to be the same as the speed regulation refresh period of the active unwinding motor 6 or its integer frequency division relationship, so that angle sampling, smoothing processing and speed output are carried out under the same rhythm, thereby avoiding lag misjudgment caused by the inconsistency between the sampling rhythm and the execution rhythm. The number of samples stored in the data cache queue represents the length of the smoothing window, which physically represents the range of continuous historical data referenced by the controller when determining attitude changes. This number of samples can be determined based on the frequency of on-site disturbances and the allowable response time: when the frequency or amplitude of short-cycle jitter on-site exceeds a set threshold, the number of samples is increased to enhance noise suppression capability; when it is desired that the controller responds to continuous offsets more quickly, the number of samples is decreased to shorten the averaging window. The controller sequentially performs the operations of reading new samples, updating the queue, calculating the average value, and outputting the smoothed angle value within a fixed period, thereby giving the smoothed angle value a clear input source and processing flow. When the buffer queue is not yet full of the preset number of samples, the controller can first calculate the average of the currently collected samples and use the result as the smoothed angle value for the transition phase; when the buffer queue is full, it will be continuously updated in a first-in-first-out manner; through this process, the system can form a usable judgment input at the beginning of the power-on, without having to wait for the entire window to be established before starting control; the above smoothing process logically constructs a moving average filtering logic model. The purpose of this model is to accurately eliminate high-frequency mechanical noise while preserving the true tension drift trend of the aluminum core. In terms of logic structure and data flow, the model receives discrete angle values ​​collected at fixed periods as input. The data flows in a fixed-length buffer queue according to the first-in-first-out rule, and after being processed by the arithmetic average operation unit, the smoothed angle value is output. This model characterizes the physical difference between the zero-mean characteristic of mechanical vibration in the time domain and the low-frequency cumulative characteristic of tension change in the time domain. Because of this averaging mechanism based on historical data windows, the system can effectively suppress the interference of transient shocks on the control logic. For example, in real engineering applications, if the high-frequency mechanical disturbances are mainly concentrated above 10Hz, the fixed period can be set to 20ms and the number of samples in the data buffer queue can be set to 10. When the controller operates according to the first-in-first-out rule to the 11th sampling period, the first sample is removed and the 11th sample enters the queue. The arithmetic mean calculation unit sums the 10 samples in the queue and divides by 10 to output the smoothed angle value. This specific queue flow mechanism ensures the clarity of data flow and interaction. At the same time, the 200ms window length can filter out high-frequency noise and meet the response requirements of tension changes, making the algorithm module fully programmable.

[0026] The process of calculating the linear displacement deviation and the target linear velocity includes: determining the linear displacement deviation based on the smoothed angle value and the short arm 16 length parameter; performing proportional and integral compensation calculations based on the linear displacement deviation to obtain the velocity compensation value; and superimposing the velocity compensation value onto the reference unwinding linear velocity to obtain the target linear velocity.

[0027] In this embodiment, the programmable logic controller takes the smoothed angle value as the input variable, first performs a sine operation to convert the angle into a dimensionless sine value corresponding to the lever geometry, and then multiplies the sine value by the length parameter of the short arm 16 to obtain the linear displacement deviation of the guide wheel 11 in the vertical direction. The linear displacement deviation is used as a control quantity and enters the speed correction calculation module, where the proportional compensation coefficient is used to respond to the current deviation in real time, and the integral compensation coefficient is used to cumulatively correct the persistent deviation. The two are superimposed to form the speed compensation value that needs to be added to the reference unwinding speed. If the displacement deviation is positive, it indicates that the aluminum core tension is too high and there is an upward trend. The target linear velocity is increased accordingly to increase the front-end feeding. If the displacement deviation is negative, it indicates that the aluminum core is supplied too fast and there is a downward trend. The target linear velocity is decreased accordingly to weaken the front-end feeding. This calculation path links the angle signal, mechanism size and feeding speed together, so that the speed correction has a clear geometric and process basis. The speed correction calculation module described above logically constitutes a proportional-integral control model. The purpose of this model is to accurately convert the geometric displacement deviation of the guide wheel 11 into a compensation command for the speed of the active unwinding motor 6. In terms of logical structure and data flow, the model takes the linear displacement deviation as a unified input and is divided into two parallel paths: one path calculates the proportional compensation value through the proportional compensation coefficient, and the other path calculates the integral compensation value by integrating over time and multiplying by the integral compensation coefficient. Finally, the two data flows are merged and superimposed to the reference unwinding linear speed to form the target linear speed. This model characterizes the physical relationship between tension deviation and feeding speed in dynamic adjustment. Because a proportional compensation path is introduced, the system can output a corresponding instantaneous correction amount for sudden tension changes, achieving a rapid response. Because an integral compensation path is introduced, the system can continuously accumulate small and persistent displacement deviations, thereby converging and eliminating the steady-state error caused by long-term feeding imbalance. To prevent the integral compensation value from accumulating infinitely under long-term unidirectional deviation, causing the target linear speed to exceed the physical limit of the active unwinding motor 6, the programmable logic controller is also equipped with anti-integral saturation logic when calculating the integral compensation value: preset upper and lower threshold values ​​for integral compensation. When the integral compensation value reaches the upper or lower threshold value, the integral accumulation operation is paused, and the current integral value is maintained. The upper and lower threshold values ​​for integral compensation are numerically equal to the difference between the maximum allowable speed adjustment upper limit and the minimum allowable speed adjustment lower limit of the active unwinding motor 6 and the reference unwinding linear speed, respectively, so as to strictly match the physical operating limit of the active unwinding motor 6. If the length parameter of the short arm 16 is 100mm and the smoothed angle value is 5°, the calculated linear displacement deviation is 8.7mm. If the proportional compensation coefficient is set to 0.5 (mm / s) / mm and the integral compensation coefficient is set to 0.1 (mm / s) / (mm·s), then the proportional compensation value for the current cycle is 4.35mm / s, and the integral compensation value is calculated based on the historical cumulative deviation. The two are superimposed on the reference unwinding line speed. This structured business logic decomposition and specific calculation example not only makes the proportional-integral control calculation process data traceable, but also ensures the programmable implementation of the software module.

[0028] Combination Figure 3 The top of the lever mechanism mounting base 3 is horizontally machined with a threaded hole 25. The adjustable bracket 8 includes a base plate 34 and a side wall 35. The base plate 34 of the adjustable bracket is machined with an elongated hole 26. Bolts 27 pass through the elongated hole 26 to fix the adjustable bracket 8 to the lever mechanism mounting base 3. The top of the adjustable bracket 8 is rotatably connected to the lever hinge shaft 9 through an angular contact ball bearing 28. The housing of the absolute value rotary encoder 14 is fixedly connected to the side wall 35 of the adjustable bracket through an L-shaped bracket 29.

[0029] In this embodiment, the top of the lever mechanism mounting base 3 is provided with a threaded hole 25, and the bottom plate 34 of the adjustable bracket is provided with an elongated hole 26. After the bolt 27 passes through the elongated hole 26 and is screwed into the threaded hole 25, the position of the adjustable bracket 8 can be slightly adjusted along the direction of the elongated hole 26 in the loosened and tightened state, and then locked in the predetermined position, thereby adjusting the relative relationship between the rotation center of the asymmetric lever 10 and the inlet of the extrusion coating die head 15; the top of the adjustable bracket 8 supports the lever hinge shaft 9 through an angular contact ball bearing 28, so that the lever hinge shaft 9 reduces the rotational friction resistance and limits the axial clearance when it is deflected by force; The housing of the absolute rotary encoder 14 is mounted on the side wall 35 of the adjustable bracket via an L-shaped bracket 29, keeping the body of the absolute rotary encoder 14 in the same position as the lever mechanism, reducing the gap and friction caused by the additional connecting rod; this mounting method facilitates position calibration according to the aluminum core specifications, the mold head inlet height and the force state of the guide wheel 11, thereby maintaining the guide wheel 11 in a working position suitable for detecting posture changes.

[0030] Combination Figure 2 and Figure 5 The active unwinding motor 6 includes an output shaft 30, which is connected to the unwinding roller 7 via a plum blossom-shaped flexible coupling 31. The tail of the extrusion coating die head 15 is connected to the main barrel 32 of the twin-screw extruder, and the PVC melt flow channel 19 is connected to the main barrel 32 of the twin-screw extruder.

[0031] In this embodiment, the output shaft 30 of the active unwinding motor is connected to the unwinding roller 7 through a plum blossom-shaped elastic coupling 31. The plum blossom-shaped elastic coupling 31 is used to compensate for the coaxiality deviation between the output shaft 30 of the active unwinding motor and the shaft of the unwinding roller 7, and to buffer the impact load transmitted to the unwinding roller 7 during the start-up and speed regulation process, so as to make the aluminum core release process more stable. The tail of the extrusion coating die 15 is connected to the main barrel 32 of the twin-screw extruder. The PVC melt conveyed in the main barrel 32 of the twin-screw extruder enters the high-pressure zone of the die through the PVC melt flow channel 19, forming a continuous coating layer on the outer periphery of the aluminum core through the channel 18. Since the release speed of the unwinding roller 7 and the extrusion state of the PVC melt in the die are coordinated by the controller, the aluminum core supply and melt coating can maintain a matching relationship, reducing the fluctuation of the coating thickness in the circumferential direction.

[0032] Example 2: Combination Figure 6 A control method for a continuous extrusion coating molding equipment for an aluminum core with an outer PVC layer includes: S1: When the aluminum core is statically tensioned and the asymmetric lever 10 is in the horizontal reference position, set the current angle value output by the absolute rotary encoder 14 to the zero angle position, and set the short arm 16 length parameter, safety angle range and reference unwinding speed in the programmable logic controller. S2: The active unwinding motor 6 drives the unwinding roller 7 to rotate and release the aluminum core. The aluminum core is guided by the guide wheel 11 and enters the extrusion coating die head 15. When the tension of the aluminum core changes, the asymmetric lever 10 causes angular displacement around the lever hinge shaft 9. When the angular displacement exceeds the mechanical clearance of the claw coupling 13 with clearance, the absolute value rotary encoder 14 outputs the angle value. S3: The programmable logic controller performs smoothing calculations on the continuously collected angle values ​​to obtain smoothed angle values, and compares the smoothed angle values ​​with the safe angle range; if the smoothed angle value is less than or equal to the upper limit of the safe angle range and greater than or equal to the lower limit of the safe angle range, the current speed of the active unwinding motor 6 remains unchanged; if the smoothed angle value is greater than the upper limit of the safe angle range or less than the lower limit of the safe angle range, the speed compensation calculation process is triggered. S4: The programmable logic controller calculates the linear displacement deviation of the aluminum core in the vertical direction based on the smoothed angle value and the length parameter of the short arm 16, and calculates the target linear velocity of the active unwinding motor 6 based on the linear displacement deviation. S5: The active unwinding motor 6 runs at the target linear speed, changing the front-end supply of the aluminum core; when the asymmetric lever 10 returns to the mechanical clearance range of the claw coupling 13 with clearance under the return torque of the planar spiral hairspring 12, the programmable logic controller stops adding speed compensation.

[0033] The control method of this embodiment is applicable to the continuous operation of the above-mentioned equipment. When the equipment is initialized, under the condition that the aluminum core is in a static tension state and the asymmetric lever 10 maintains a horizontal reference position, the current angle of the absolute value rotary encoder 14 is set to the zero angle position, and the short arm 16 length parameter, safety angle range and reference unwinding speed are written into the programmable logic controller. During operation, the active unwinding motor 6 drives the unwinding roller 7 to release the aluminum core, which enters the extrusion coating die head 15 via the guide wheel 11. When the tension of the aluminum core changes and pushes the asymmetric lever 10 to deflect, if the deflection exceeds the mechanical clearance reserved by the claw coupling 13 with gap, the absolute value rotary encoder 14 outputs the corresponding angle value. After the controller performs smoothing calculation on the continuous angle values, it compares them with the safe angle range. If the angle is within the range, the speed of the active unwinding motor 6 is kept constant. If the angle exceeds the range, speed compensation calculation is performed. The controller calculates the linear displacement deviation based on the smoothed angle value and the length parameter of the short arm 16, and then obtains the target linear velocity accordingly, which is then sent to the active unwinding motor 6. As the front-end supply is adjusted, the aluminum core tension gradually approaches the set state. Under the return torque of the planar spiral spring 12, the asymmetric lever 10 returns to the mechanical clearance range, the controller stops adding compensation, and the system maintains the current feeding state. This method connects mechanical detection, angle smoothing, geometric conversion, and speed correction into an executable process, so that the aluminum core maintains controllable micro-tension and a centered posture before entering the die head. In this embodiment, the zero angle in S1 is used to characterize the reference posture of the asymmetric lever 10 when the aluminum core is under reference tension. The method of determination is as follows: first, the aluminum core is made to be in a static tension state between the unwinding end and the traction end, and then the position of the adjustable bracket 8 or the working height of the guide wheel 11 is adjusted so that the asymmetric lever 10 reaches the predetermined horizontal reference position. The current output value of the absolute value rotary encoder 14 is read and written to the controller as the zero position reference. In the subsequent operation, the controller first performs zero position offset correction on the angle value collected in real time, and then enters the smoothing calculation, so as to ensure that the subsequent comparison and compensation are all carried out around the same reference posture. In this embodiment, the safe angle range and the reference unwinding linear speed in S1 are both derived from the trial run calibration results. Specifically, after the extrusion coating die 15 and the rear traction enter a stable working condition, the active unwinding motor 6 is kept running at a speed matching the traction speed, and angle samples and unwinding roller 7 linear speed samples are continuously recorded over a period of time. The average linear speed of the unwinding roller 7 during stable operation is set as the reference unwinding linear speed, and the normal fluctuation range of the angle samples during stable operation, combined with the process allowable margin, is set as the safe angle range. Thus, the reference unwinding linear speed represents the normal feeding state, and the safe angle range represents the normal attitude fluctuation boundary. Together, they constitute the benchmark for subsequent control decisions. In this embodiment, the processing flow of S3 and S4 is executed according to a clear data flow sequence; its input source is the raw angle value continuously output by the absolute value rotary encoder 14; the controller first receives the raw angle value according to a fixed sampling period, then averages multiple continuous angle samples to obtain a smoothed angle value; then compares the smoothed angle value with the safe angle range to determine whether to start speed compensation. The controller only calls the short arm 16 length parameter when the judgment result is outside the range, converts the angle offset into the vertical displacement deviation of the guide wheel 11 relative to the zero position; a new target linear velocity is generated based on the displacement deviation and sent to the active unwinding motor 6; the output of this process is the smoothed angle value, the linear displacement deviation and the target linear velocity in sequence, with the former result serving as the input for the latter, ensuring that the control logic has a clear data mapping relationship and traceability; In this embodiment, the stop speed compensation in S5 means that after the controller detects that the smoothed angle value has returned to the safe angle range and the mechanical transmission corresponding to the asymmetric lever 10 has fallen back into the mechanical clearance range of the claw coupling 13 with clearance, it will no longer increase or decrease the compensation amount on the reference unwinding speed, but will maintain the current output speed and continue to monitor subsequent angle changes. If the subsequent angle value exceeds the safe angle range again, the speed compensation calculation process is restarted. Through this reciprocating judgment method, the controller only corrects persistent attitude imbalances and does not frequently act on short-term, self-recoverable micro-disturbances. To verify the technical effect of the control method in this embodiment, a set of comparative experiments were conducted. The experimental conditions used an aluminum core with an outer diameter of 3mm, PVC material with a target coating thickness of 1mm, and the extruder and traction machine speeds were kept constant. The control group used traditional constant speed unwinding control, while the experimental group used the control method of this embodiment. After continuous production of 1000m, samples were taken at every 100m intervals for eccentricity measurement. Experimental data showed that the eccentricity of the control group samples fluctuated between 5% and 12%, and there was obvious periodic uneven wall thickness. In contrast, the eccentricity of the experimental group samples was stably controlled within 2% to 4%. This comparative experimental data demonstrates the significant improvement of this invention in isolating mechanical disturbances and compensating for tension deviations in real time. It effectively supports the technical effect of solving the problem of eccentricity caused by aluminum core posture fluctuations and micro-tension drift before mold insertion, ensuring the rationality of the effect-means correspondence.

[0034] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A continuous extrusion coating molding device for an aluminum core with an outer PVC layer, characterized in that, include: The main frame (1) is fixedly connected in sequence to the front unwinding support (2), the lever mechanism mounting base (3), the die mounting platform (4) and the rear traction base (5) along the aluminum core conveying direction; the active unwinding motor (6) is fixedly connected to the front unwinding support (2) and drives the unwinding roller (7) supported on it to rotate. An adjustable bracket (8) is fixed to the lever mechanism mounting base (3), and a lever hinge shaft (9) rotatably connected thereto is fixed to an asymmetric lever (10); the asymmetric lever (10) includes a short arm (16) and a long arm (17), the end of the short arm (16) is rotatably connected to a guide wheel (11), and the end of the long arm (17) is fixed to a planar spiral hairspring (12) that provides the initial return torque. An absolute rotary encoder (14) is coaxially connected to the end of the lever hinge shaft (9) via a gapped claw coupling (13) to collect angle values; an extrusion coating die (15) is fixed to the die mounting platform (4) and has an aluminum core through channel (18) and a PVC melt flow channel (19); the gapped claw coupling (13) is a three-jaw staggered fit structure, including a driving claw disc (20) and a driven claw disc (21), the driving claw disc (20) is fixed to the lever hinge shaft (9), and the absolute rotary encoder (14) contains an absolute rotary encoder. The input shaft (33) of the encoder is fixed to the input shaft (33) of the absolute rotary encoder; a mechanical gap is reserved in the circumferential direction between the protruding claw (22) of the active claw (20) and the groove (23) of the passive claw (21); when the swing angle of the lever hinge shaft (9) is less than or equal to the mechanical gap, the active claw (20) rotates freely within the mechanical gap; when the swing angle of the lever hinge shaft (9) exceeds the mechanical gap, the active claw (20) engages with the passive claw (21); The programmable logic controller is electrically connected to the active unwinding motor (6) and the absolute rotary encoder (14), and pre-stores the safety angle range, the reference unwinding linear speed and the length parameters of the short arm (16); Its configuration is as follows: smooth the collected angle values ​​to obtain smoothed angle values; if the smoothed angle values ​​are within the range, maintain the speed of the active unwinding motor (6) unchanged; If the deviation exceeds the limit, the linear displacement deviation of the guide wheel (11) relative to the zero position in the vertical direction is calculated according to the length parameter and the smoothed angle value, by first performing a sine operation on the smoothed angle value and then multiplying the obtained sine value with the length parameter; the zero position is the position of the guide wheel (11) when the asymmetric lever (10) is in the horizontal reference position; the target linear velocity is calculated according to the linear displacement deviation and the active unwinding motor (6) is controlled to run.

2. The continuous extrusion coating molding equipment for an aluminum core with an outer PVC layer as described in claim 1, characterized in that, The outer circumference of the guide wheel (11) is machined with a semi-circular guide groove (24) that matches the outer diameter of the aluminum core; the outer end of the planar spiral hairspring (12) is fixed to the long arm (17), and the inner end of the planar spiral hairspring (12) is fixed to the adjustable bracket (8).

3. The continuous extrusion coating molding equipment for an aluminum core with an outer PVC layer as described in claim 1, characterized in that, The programmable logic controller is configured to: establish a data buffer queue with a fixed period, and perform an average calculation on multiple continuously collected angle values ​​to obtain the smoothed angle value.

4. The aluminum core outer PVC continuous extrusion coating molding equipment as described in claim 3, characterized in that, The process of calculating the linear displacement deviation and the target linear velocity includes: determining the linear displacement deviation based on the smoothed angle value and the length parameter of the short arm (16); performing proportional and integral compensation calculations based on the linear displacement deviation to obtain a speed compensation value; and superimposing the speed compensation value onto the reference unwinding linear velocity to obtain the target linear velocity.

5. The continuous extrusion coating molding equipment for an aluminum core with an outer PVC layer as described in claim 1, characterized in that, The top of the lever mechanism mounting base (3) is horizontally machined with a threaded hole (25). The adjustable bracket (8) includes a base plate (34) and a side wall (35) of the adjustable bracket. The base plate (34) of the adjustable bracket is machined with an elongated hole (26). Bolts (27) pass through the elongated hole (26) to fix the adjustable bracket (8) to the lever mechanism mounting base (3). The top of the adjustable bracket (8) is rotatably connected to the lever hinge shaft (9) via an angular contact ball bearing (28), and the housing of the absolute rotary encoder (14) is fixedly connected to the side wall (35) of the adjustable bracket via an L-shaped bracket (29).

6. The continuous extrusion coating molding equipment for aluminum core outer PVC as described in claim 1, characterized in that, The active unwinding motor (6) includes an output shaft (30) of the active unwinding motor, and the output shaft (30) of the active unwinding motor is connected to the unwinding roller (7) through a plum blossom-shaped flexible coupling (31); the tail of the extrusion coating die (15) is connected to the main barrel (32) of the twin-screw extruder, and the PVC melt flow channel (19) is connected to the main barrel (32) of the twin-screw extruder.

7. The control method for the continuous extrusion coating molding equipment for an aluminum core with an outer PVC layer as described in claim 1, characterized in that, include: S1: When the aluminum core is statically tensioned and the asymmetric lever (10) is in a horizontal reference position, the current output angle value of the absolute value rotary encoder (14) is set to the angle zero position, and the length parameter of the short arm (16), the safe angle range and the reference unwinding speed are set in the programmable logic controller. S2: The active unwinding motor (6) drives the unwinding roller (7) to rotate and release the aluminum core. The aluminum core is guided by the guide wheel (11) and enters the extrusion coating die head (15). When the change in the tension of the aluminum core causes the asymmetric lever (10) to generate an angular displacement around the lever hinge axis (9), and the angular displacement exceeds the mechanical clearance of the claw coupling (13) with clearance, the absolute value rotary encoder (14) outputs the angle value. S3: The programmable logic controller performs smoothing calculations on the continuously collected angle values ​​to obtain smoothed angle values, and compares the smoothed angle values ​​with the safe angle range; if the smoothed angle values ​​are less than or equal to the upper limit of the safe angle range and greater than or equal to the lower limit of the safe angle range, the current speed of the active unwinding motor (6) remains unchanged. If the smoothed angle value is greater than the upper limit of the safe angle range or less than the lower limit of the safe angle range, the speed compensation calculation process is triggered. S4: The programmable logic controller calculates the linear displacement deviation of the aluminum core in the vertical direction based on the smoothed angle value and the length parameter of the short arm (16), and calculates the target linear velocity of the active unwinding motor (6) based on the linear displacement deviation. S5: The active unwinding motor (6) runs at the target linear speed, changing the front end supply of the aluminum core; when the asymmetric lever (10) retracts to the mechanical clearance range of the claw coupling (13) with gap under the return torque of the planar spiral hairspring (12), the programmable logic controller stops adding speed compensation.

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