Control method for improving strip head bending caused by jaw coiling and application

Abstract

The invention discloses a control method and application for improving strip head bending caused by jaw coiling, and the control method comprises the following steps: at the initial stage of strip steel coiling, setting the linear speed of a coiling machine mandrel to be higher than the linear speed of a tension roller, then gradually reducing the linear speed of the coiling machine mandrel until the linear speed is synchronous with the tension roller, and completing coiling to obtain a strip steel coil; and discharging of the strip steel coil is completed. In the initial stage of strip steel coiling, the linear speed of the coiling machine mandrel is set to be higher than the linear speed of rotation of the tension roller, then the linear speed of the coiling machine mandrel is gradually reduced for normal coiling, weak front tension is formed at the head of the strip steel through the speed difference, vertical bending or stacking caused by loosening is avoided, strip head bending caused by gravity is reduced, and the coiling efficiency is improved. The unfavorable condition that the belt head is curled is reduced, eccentric convex hulls are eliminated, cutting of the belt head by an outlet is reduced, and the yield is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coiled material winding and unloading, and in particular to a control method and application for improving the bending of a strip head caused by jaw winding. Background Art

[0002] Modern cold-rolled pickling lines, due to the relatively thick strip produced, often incorporate a jaw mechanism on the coiler mandrel to account for the strip's strength and rigidity. During coiling, the strip head is introduced into the jaws, where pressure tongues clamp the strip head while the coiler mandrel expands, and the coiler motor rotates the mandrel to coil the strip. However, due to the inherent depth and slope of the jaws as the strip head enters the jaws and begins coiling, the strip head can bend, affecting subsequent packaging and increasing the difficulty of handling the coils during repacking. Furthermore, during strip unloading, the unloading trolley saddle supports the strip while the coiler mandrel shrinks, freeing the coiler mandrel from the inner ring of the strip. Once the coiler mandrel shrinks, the pressure rollers open, the support arms withdraw, and the unloading trolley moves out. This traditional unloading process also makes it difficult to control strip head bending.

[0003] Some corresponding measures have been taken to address the effects of strip head bending. For example, CN105290151A discloses a method for controlling the unwinding of a coiler with jaws. This method involves reducing the diameter of the coiler mandrel and opening the jaws to loosen the strip head, rotating the coiler mandrel to release the strip head from the jaws, expanding the coiler mandrel and closing the jaws to flatten the strip head, and then reducing the coiler mandrel again to unwind the coil, thus avoiding bending and warping of the strip head. However, this method does not optimize the winding process, and the subsequent expansion and flattening of the coiler mandrel may not be able to effectively flatten the bent strip head. CN109772930A discloses a method for controlling coil unloading of a jaw coiler. This method uses a graded control method to adjust the coiler mandrel's expansion and contraction, as well as its rotation times, according to the coiler's coiled strip specifications. The method gradually removes the strip clamped within the jaws during coiling and flattens the removed strip in stages, minimizing friction and obstruction between the strip head, the coiler mandrel, and the jaw mechanism during unloading. This control method significantly increases the coiler mandrel's operating time and reduces unloading efficiency.

[0004] At present, there are few methods reported to control the strip coiling and reduce the bending of the strip head. Regulation from the source may achieve better control effects. Summary of the Invention

[0005] In order to overcome the problems existing in the prior art, the present invention provides a control method for improving the bending of the belt head caused by the jaw winding, comprising: At the beginning of strip coiling, the linear speed of the coiler mandrel is set higher than that of the tension roller, and then the linear speed of the coiler mandrel is gradually reduced until it is the same as that of the tension roller, completing the coiling and obtaining the strip coil; Complete the unloading of the strip steel coil.

[0006] Furthermore, in the initial stage of coiling the strip, setting the linear speed of the coiler mandrel to be higher than that of the tension roller specifically includes: During the first three turns of winding, an advance speed is provided. The advance speed is the difference between the linear speeds of the winding machine core shaft and the tension roller, and its value is 1.5%-3.0% of the linear speed of the tension roller.

[0007] Furthermore, the advance speed per lap is adjusted within a range of 10% to 30%.

[0008] The design concept of this invention is that when the strip head enters the jaws and begins to coil, a tension difference is created between the tension roller and the coiler through the speed difference between the coiler core shaft and the tension roller, i.e., the lead speed. This reduces the relative speed difference between the strip and the jaws, lowering the clamping force required and avoiding head creases caused by excessive bending. Under the action of the lead speed, the jaw bar swings and presses the bend of the strip head, making the strip head fit the surface of the coiler core shaft and eliminating eccentric bulges. The lead speed during coiling and establishment is adjusted by 10%-30% per revolution. The speed difference creates a slight front tension in the strip head, preventing sagging or stacking caused by slack and reducing bending of the strip head caused by gravity.

[0009] Furthermore, when winding 4-8 turns, the advance speed is reduced turn by turn until it reaches 0.

[0010] Furthermore, the unloading of the strip steel coil includes: The saddle of the unloading trolley rises until it contacts the bottom of the coil to be unloaded, reaches the supporting pressure, and stops rising; The jaws of the coiler mandrel open, loosen the tape head, and remove it from the jaws; The coiler mandrel is driven to reduce its diameter so that the strip coil and the coiler mandrel are separated, and the unloading trolley lifts the strip coil and moves it out of the coiler mandrel.

[0011] Furthermore, before driving the coiler core shaft to reduce its diameter, the coiler core shaft is controlled to expand its diameter several times to flatten the strip head.

[0012] Furthermore, the stripping out of the jaws includes driving the coiling machine core shaft to reduce its diameter and rotate, and when the rotation time is reached, the rotation is stopped, and the belt head is stripped out of the jaws.

[0013] Furthermore, the rotation time of the coiler core shaft is 900-1200ms.

[0014] Furthermore, the unloading trolley lifting the steel coil out of the coiler mandrel includes: The unloading trolley carries the steel coil out of the coiler core shaft at a low speed. After moving to the set safety position and confirming that it is normal, it moves forward at a high speed out of the unloading area to complete the unloading.

[0015] The present invention also provides the application of the above-mentioned control method for improving strip head bending caused by jaw coiling in strip coiling production.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention sets the linear speed of the coiler core shaft to be higher than the linear speed of the tension roller in the initial stage of strip coiling, and then gradually reduces the linear speed of the coiler core shaft for normal coiling. A weak front tension is formed at the head of the strip through the speed difference, thereby avoiding sagging or stacking caused by relaxation, reducing the bending of the strip head caused by gravity, reducing the occurrence of undesirable conditions of strip head curling, eliminating eccentric bulges, reducing the cutting of the strip head at the outlet, and improving the yield rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 A flow chart showing a method for controlling the improvement of the bending of the tape head caused by the winding of the jaws is shown; Figure 2 A physical picture of a steel coil obtained by an existing production line without using any control method is shown; Figure 3 A physical picture of a steel coil obtained by applying the control method of Example 1 is shown; Figure 4 A physical picture of a steel coil obtained by applying the control method of Example 2 is shown; Figure 5 A physical picture of a steel coil obtained by applying the control method of Comparative Example 1 is shown; Figure 6 A physical picture of a steel coil obtained by applying the control method of Comparative Example 2 is shown. DETAILED DESCRIPTION

[0019] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the specific embodiments of the present invention and the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] Example 1 like Figure 1 As shown, a method for improving the control of the bending of the belt head caused by the jaw winding includes the following steps: S101, coiling preparation stage: the strip head bites into the jaws of the coiler, the photoelectric sensing device detects the strip head position and starts to transmit a signal, and the coiler mandrel transmission device of the coiler starts to move and enters the coiling stage.

[0022] S102, coiling starts: the core shaft starts to rotate and enters the advance speed mode, the advance speed mode: the linear speed of the coiler is greater than the linear speed of the tension roller, the advance speed = the linear speed of the coiler - the linear speed of the tension roller; the advance speed is controlled by PLC to be 1.5-3.0% of the linear speed of the tension roller, and a tension difference is formed between the tension roller and the coiling through the speed difference. The tension difference is about 50% of the tension provided by the tension roller. The specific value of the advance speed is adjusted according to the strip specifications. This process continues until the strip is coiled for 3 turns. The advance speed of each turn is adjusted within the range of increase or decrease of 20%.

[0023] S103, coiling speed reduction: During the process of coiling the strip 4-8 times, the leading speed is continuously reduced to 0, and finally the linear speed of the coiler is made consistent with the linear speed of the tension roller, and the normal coiling mode is entered.

[0024] S104, normal coiling: In normal mode, the linear speed of the coiler is consistent with the linear speed of the tension roller. The weight of the steel coil is automatically calculated in real time according to the PLC setting program. When the steel coil reaches the weight, it is cut and unloaded.

[0025] S105, coil unloading starts: PLC program controls the coil unloading trolley saddle to start rising. When the coil unloading trolley saddle starts to contact with the strip coil and the detected pressure value reaches the support pressure, the coil unloading trolley saddle stops rising.

[0026] S106, expansion and contraction of the coiler core shaft: After detecting the pressure signal, the PLC controls the coiler core shaft to shrink and rotate. When the rotation time reaches 1000ms, the coiler core shaft stops rotating and the strip head is released from the jaws; the PLC controls the coiler core shaft to expand and flatten the strip head, and repeats the expansion and flattening operation 2-3 times to further control the bending of the strip head; during this process, the strip coil has a slight rotational displacement, and the rotatable saddle of the unloading trolley can rotate with the strip to avoid the strip coil from shaking due to friction.

[0027] S107, normal unloading: The unloading trolley carries the steel coil out of the coiler core shaft at a low speed, moves to the set safety position and after confirmation that it is normal, it moves forward at high speed out of the unloading area to complete the unloading.

[0028] The main working mechanism of this embodiment includes: the jaws need to provide sufficient clamping force at the initial stage of coiling. T s Greater than or equal to the bending tension of the strip T b , ; in, b 、 h and σ s are the width, thickness and yield strength of the strip respectively, D is the diameter of the coiler mandrel.

[0029] The advance speed minimizes the relative speed difference between the strip and the jaws, lowering the clamping force required and preventing creases at the strip's head due to excessive bending. At the advance speed, the jaws swing to compress the strip's bend, forcing it to conform to the coiler's core surface and eliminating eccentric bulges. During the first three coiling turns, the advance speed is adjusted within a 20% increment per turn. This speed differential creates a slight front tension at the strip's head, preventing sagging or stacking due to slack and reducing gravitational head bending.

[0030] Example 2 Compared with Example 1, the difference is that in step S106, after the strip head is released from the jaws, the coiler core shaft is not controlled to expand the strip head to flatten it.

[0031] Comparative Example 1 Compared with Example 1, the difference is that after the rotation time in step S106 is reduced from 1000ms to 600ms, the rotation of the coiler core shaft is stopped.

[0032] Comparative Example 2 A method for improving the control of the bending of the belt head caused by the jaw winding includes the following steps: T101. Coiling of strip steel coil: The strip head bites into the jaws of the coiler, the photoelectric sensing device detects the position of the strip head and starts to transmit a signal, the coiler mandrel transmission device starts to move and enters the coiling stage, the mandrel rotates, and the coiling of the strip steel coil is completed.

[0033] T102, coil unloading starts: PLC program controls the coil unloading trolley saddle to start rising. When the coil unloading trolley saddle starts to contact with the strip coil, the detected pressure value reaches the support pressure, and the coil unloading trolley saddle stops rising.

[0034] T103, expansion and contraction of the coiler core shaft: After detecting the pressure signal, the PLC controls the coiler core shaft to drive the coiler core shaft to reduce its diameter and rotate. When the rotation time reaches 600ms, the coiler core shaft stops rotating and the strip head is released from the jaws; the PLC controls the coiler core shaft to expand the strip head and flatten the strip head. The expansion and flattening operations are repeated 2-3 times to further control the bending of the strip head. During this process, the strip coil has a slight rotational displacement, and the rotatable saddle of the unloading trolley can rotate with the strip to avoid shaking of the strip coil due to friction.

[0035] T104, normal unloading: The unloading trolley carries the steel coil out of the coiler core shaft at a low speed, moves to the set safety position and after confirmation that it is normal, it moves forward at high speed out of the unloading area to complete the unloading.

[0036] from Figure 2 It can be seen that in the current production process, there is no control over coiling and uncoiling, and the strip head has obvious bending. Figure 3 and Figure 4 It can be seen that both Example 1 and Example 2 of the present invention can effectively control the bending of the strip head and meet the needs of customers. In particular, Example 1, under the premise of introducing the advanced speed mode, extends the diameter reduction rotation of the coiler mandrel, and controls the diameter expansion action of the coiler mandrel to flatten the strip head before unloading, which basically eliminates the bending of the strip head, and at the same time, the eccentric bulge is extremely slight. However, from Figure 5 It can be seen that in Comparative Example 1, due to the short time the coiler mandrel rotates to reduce its diameter, the strip head fails to fully disengage from the jaws, resulting in multiple bend marks on the strip head. Compared to Example 1, Comparative Example 2 does not employ the advanced speed mode; instead, it controls the coiler mandrel to expand and flatten the strip head before unloading. While this largely eliminates bends in the strip head, a noticeable eccentric bulge remains.

[0037] To sum up, the present invention sets the linear speed of the coiler core shaft to be higher than that of the tension roller in the initial stage of strip coiling, and then gradually reduces the linear speed of the coiler core shaft for normal coiling. A weak front tension is formed at the head of the strip through the speed difference, thereby avoiding sagging or stacking caused by relaxation, reducing the bending of the strip head caused by gravity, and further using the coiler core shaft to expand and flatten in certain application scenarios. Such a control method reduces the occurrence of undesirable conditions of strip head curling, eliminates eccentric bulges, reduces the cutting of the strip head at the outlet, and improves the yield rate.

[0038] Devices, components, methods, etc. not described in detail in the present invention are all prior art and are implemented according to common understanding in the art.

[0039] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. 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 method for improving the control of the bending of the belt head caused by the jaw winding, characterized in that: include At the beginning of strip coiling, the linear speed of the coiler mandrel is set higher than that of the tension roller, and then the linear speed of the coiler mandrel is gradually reduced until it is the same as that of the tension roller, completing the coiling and obtaining the strip coil; Complete the unloading of the strip steel coil.

2. The method for improving the control of the belt head bending caused by the jaw winding according to claim 1 is characterized in that: The method of setting the linear speed of the coiler mandrel to be higher than the tension roller in the initial stage of coiling the strip specifically includes: During the first three turns of winding, an advance speed is provided. The advance speed is the difference between the linear speeds of the winding machine core shaft and the tension roller, and its value is 1.5%-3.0% of the linear speed of the tension roller.

3. The method for improving the control of the belt head bending caused by the jaw winding according to claim 2, characterized in that: The advance speed of each lap is adjusted within the range of 10%-30%.

4. The method for improving the control of the belt head bending caused by the jaw winding according to claim 2, characterized in that: When winding 4-8 turns, reduce the advance speed turn by turn until it reaches 0.

5. The method for improving the control of the belt head bending caused by the jaw winding according to claim 1, characterized in that: The process of completing the unloading of the strip steel coil comprises: The saddle of the unloading trolley rises until it contacts the bottom of the coil to be unloaded, reaches the supporting pressure, and stops rising; The jaws of the coiler mandrel open, loosen the tape head, and remove it from the jaws; The coiler mandrel is driven to reduce its diameter so that the strip coil and the coiler mandrel are separated, and the unloading trolley lifts the strip coil and moves it out of the coiler mandrel.

6. The method for improving the control of the belt head bending caused by the jaw winding according to claim 5, characterized in that: Before driving the coiler mandrel to reduce its diameter, the coiler mandrel is also controlled to expand its diameter several times to flatten the strip head.

7. The method for improving the control of the belt head bending caused by the jaw winding according to claim 5, characterized in that: The stripping jaws include driving the coiling machine core shaft to reduce its diameter and rotate, and when the rotation time is reached, the rotation is stopped and the strip head is stripped out of the jaws.

8. The method for improving the control of the belt head bending caused by the jaw winding according to claim 7, characterized in that: The rotation time of the coiler core shaft is 900-1200ms.

9. The method for improving the control of the belt head bending caused by the jaw winding according to claim 5, characterized in that: The unloading trolley lifting the steel coil out of the coiler core shaft includes: The unloading trolley carries the steel coil out of the coiler core shaft at a low speed. After moving to the set safety position and confirming that it is normal, it moves forward at a high speed out of the unloading area to complete the unloading.

10. Application of the control method for improving strip head bending caused by jaw coiling as claimed in any one of claims 1 to 9 in strip coiling production.

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