Automatic yarn feeding and splicing method based on suction-type airflow rotor spinning machine

Abstract

The present invention designs an automatic yarn feeding and splicing method based on a suction-type airflow rotor spinning machine. For yarn breakage during rotor spinning, the method first involves design of a a structure and action sequence of an automatic yarn‑feeding apparatus, to achieve automatic cleaning out of residual fibers inside a spinning device. Then, a yarn‑grasping arm structure of the automatic yarn‑feeding apparatus is controlled to locate a broken yarn from a bobbin, and position same at a specific location; after being cut to a fixed length, the yarn enters a yarn‑leading tube with a negative‑pressure airflow, thereby realizing an automatic yarn‑feeding function. Subsequently, a doffing mechanism is controlled to unwind the broken yarn into a rotor collecting groove as seed yarn, where it overlaps, wraps and twists with the fiber flow formed by a sliver fed by a feed roller having passed through an opening roller and a fiber transport channel, thus completing automatic splicing. Moreover, by means of precisely calculating an overlap length between the seed yarn and the fiber flow, as well as the twisting time, parameters such as linear density, twist and strength of the seed yarn‑fiber flow twisted composite are regulated, thereby finishing automatic splicing and entering normal spinning operation, which enhances production efficiency for enterprises.

Description

Automatic yarn-forming splicing method based on air-assisted rotor spinning machine Technical Field

[0001] This invention relates to an automatic yarn-forming splicing method for a rotary spinning machine based on a vacuum-type airflow spinning cup, belonging to the field of spinning automation technology. Background Technology

[0002] In rotor spinning, sudden yarn breakage requires splicing. Common methods include manual splicing and semi-automatic mechanical splicing. Both methods involve the following four steps: ① Cleaning away any remaining fibers inside the rotor; ② Locating the broken yarn from the bobbin and pulling out a certain length, using it as seed yarn in the guide tube, and extending it into the rotor under negative pressure; ③ Starting the feed roller to feed a sliver, which intersects and wraps with the seed yarn inside the rotor to achieve splicing; ④ Starting the winding mechanism to guide the yarn into normal spinning mode.

[0003] Regarding the problem of sudden yarn breakage, existing technical solutions have the following problems: ① After breakage, the orderly movement of the spinning unit's mechanical structure cannot be controlled to achieve the purpose of automatically cleaning the residual fibers in the spinneret; ② The yarn tail after breakage is wound onto the yarn package, and automatic yarn generation cannot be achieved; ③ After breakage, how to control the length of the yarn generation is necessary not only to ensure that the yarn tail of the generation stays in the yarn guide tube, but also to design its reverse length as the seed yarn to ensure that the seed yarn and the fiber sliver condensed in the rotor can overlap and intersect at the rotor peeling point to form a joint. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an automatic yarn breakage and splicing method based on a vacuum-type airflow rotor spinning machine. The yarn breakage method is designed and implemented through a structural automation control method, and the designed splicing method is executed efficiently, effectively solving the problem of sudden yarn breakage during rotor spinning and improving splicing efficiency.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] 1. An invention based on an automatic yarn head generation method using a yarn gripping arm mechanism: By designing the structure of the yarn gripping arm and its sequential motion, the yarn tail wound onto the yarn cone is located and positioned at a specific position. After being cut to a fixed length, it enters the yarn guide tube with the negative pressure airflow, thus realizing the automatic yarn head generation function.

[0007] 2. A method for controlling the release length of seed yarn based on the change of the storage yarn length: By controlling the reversing speed and time of the winding roller, the length of the yarn stored in the storage tube under negative pressure is controlled, and the length range of the yarn in the storage tube released as seed yarn by the yarn guiding roller at the beginning of splicing is further controlled.

[0008] 3. A method for automatic splicing of seed yarn and fiber flow within the rotor: For different rotor spinning equipment, different spinning raw materials, and processes, the method coordinates the changes in the cotton roller start-up time, seed yarn release length and time, and winding time to regulate the overlap length and twisting time of the seed yarn and fiber flow. Furthermore, it regulates the morphology and mechanical properties of the seed yarn-fiber flow twisted assembly, improving the quality of the splicing and achieving automatic splicing.

[0009] The automatic yarn-forming and splicing method for a vacuum-type airflow rotor spinning machine described in this invention, compared with the prior art, has the following technical advantages:

[0010] This invention designs an automatic yarn-forming and splicing method based on a vacuum-type airflow rotor spinning machine. When yarn breaks due to unforeseen circumstances during rotor spinning, the automatic yarn-forming and splicing method, guided by the configured automatic yarn-forming and splicing device, enables the automatic yarn-forming and splicing of the broken yarn and returns the machine to normal spinning state through coordinated control. First, by designing the structure and sequential operation of the automatic yarn-forming device, the automatic cleaning of residual fibers within the spinning machine is achieved. Then, the yarn-grabbing arm of the automatic yarn-forming device locates the broken yarn on the yarn package and positions it at a specific location. After being cut to a fixed length, it enters the yarn guide tube with negative pressure airflow, realizing the automatic yarn-forming function. Next, the doffing mechanism controls the broken yarn to unwind as seed yarn into the rotor's condensing groove. This yarn overlaps and twists with the fiber flow formed by the sliver fed by the cotton roller through the carding roller and fiber conveying channel, completing the automatic splicing function. Finally, to improve the splicing success rate, based on the yarn dwell position of the automatic yarn-forming function, the overlap length and twisting time of the seed yarn and fiber flow are precisely calculated to further adjust the linear density, twist, and strength parameters of the seed yarn-fiber flow twisted body, ensuring high-quality automatic splicing and returning to normal spinning state. This achieves highly efficient and fully automatic yarn-forming and splicing functions in the event of sudden yarn breakage during rotor spinning, improving enterprise production efficiency. Attached Figure Description

[0011] Figure 1 is a flowchart of the head-forming method in the automatic head-forming and splicing method based on the air-suction rotor spinning machine of the present invention.

[0012] Figure 2 is a schematic diagram of the tail yarn starting length control in the automatic starting splicing method of the present invention based on the air-suction rotor spinning machine.

[0013] Figure 3 is a flowchart of the splicing method in the automatic head splicing method based on the air-suction rotor spinning machine of the present invention.

[0014] Figure 4 is a schematic diagram of the joint structure in the automatic head splicing method of the present invention based on the air-suction rotor spinning machine.

[0015] Figure 5 is a schematic diagram of the joint morphology and structure in the automatic head splicing method of the present invention based on the air-suction rotor spinning machine.

[0016] Figure 6 is a schematic diagram of a structure of a rotary spinning machine based on a suction-type airflow rotor involved in the design method of the present invention.

[0017] Figure 7 is a schematic diagram of a winding roller in a rotary spinning machine based on a vacuum airflow rotor, which is involved in the design method of the present invention.

[0018] Figure 8 is a schematic diagram of a yarn guide plate in a rotary spinning machine based on a vacuum airflow rotor, which is involved in the design method of the present invention.

[0019] Figure 9 is a schematic diagram of a yarn-grabbing arm in a rotary spinning machine based on a suction-type airflow rotor, which is involved in the design method of this invention.

[0020] Figure 10 is a schematic diagram of a connection structure between the yarn guide roller and the pressure roller in a rotary spinning machine based on a vacuum airflow type, which is involved in the design method of the present invention.

[0021] Figure 11 is a schematic diagram of a connection structure between scissors and scissor cylinder in a rotary spinning machine based on a suction-type airflow mechanism, which is involved in the design method of this invention.

[0022] The components include: 1. Frame; 2. Winding bracket; 3. Yarn cone; 4. Yarn; 5. Winding roller; 6. Lifting rod; 7. Winding fixing seat; 8. Semi-automatic mounting beam; 9. Yarn guide plate; 10. Yarn breakage sensor; 11. Yarn grabbing arm; 12. Yarn positioning hook; 13. Yarn grabbing arm motor; 14. Yarn grabbing arm transmission belt; 15. Yarn grabbing arm negative pressure pipe; 16. Yarn grabbing arm fixing seat; 17. Yarn guide roller; 18. Pressure roller; 19. Pressure roller. 20. Roller support; 21. Yarn guide positioning rod; 22. Pressure roller torsion spring; 23. Pressure roller cylinder; 24. Yarn guide rod; 25. Yarn drawing mounting seat; 26. Spinning unit; 27. Yarn guide tube; 28. Scissors; 29. ​​Scissors cylinder; 30. Scissors support seat; 31. Spring; 32. Rotating shaft; 33. Yarn guide roller stepper motor; 34. Pressure roller support shaft; 35. Inclined part; 36. Arc part; 37. Positioning port. Detailed Implementation

[0023] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0024] In order to solve the above-mentioned technical problems, the present invention adopts the following technical solution design idea.

[0025] 1. An invention based on an automatic yarn head generation method using a yarn gripping arm mechanism: By designing the structure of the yarn gripping arm and its sequential motion, the yarn tail wound onto the yarn cone is located and positioned at a specific position. After being cut to a fixed length, it enters the yarn guide tube with the negative pressure airflow, thus realizing the automatic yarn head generation function.

[0026] 2. A method for controlling the release length of seed yarn based on the change of the storage yarn length: By controlling the reversing speed and time of the winding roller, the length of the yarn stored in the storage tube under negative pressure is controlled, and the length range of the yarn in the storage tube released as seed yarn by the yarn guiding roller at the beginning of splicing is further controlled.

[0027] 3. A method for automatic splicing of seed yarn and fiber flow within the rotor: For different rotor spinning equipment, different spinning raw materials, and processes, the method coordinates the changes in the cotton roller start-up time, seed yarn release length and time, and winding time to regulate the overlap length and twisting time of the seed yarn and fiber flow. Furthermore, it regulates the morphology and mechanical properties of the seed yarn-fiber flow twisted assembly, improving the quality of the splicing and achieving automatic splicing.

[0028] The automatic yarn-forming and splicing method designed in this invention based on a vacuum-type airflow rotor spinning machine can, in practical applications, automatically generate yarn when a sudden situation causes yarn breakage. This is achieved through the coordinated control of the various mechanisms of rotor spinning by PLC, which regulates the yarn breakage by finding, positioning, and storing the broken yarn. Based on the winding mechanism, the broken yarn is unwound as seed yarn into the rotor cohesive trough. The fiber flow formed by the sliver fed by the cotton roller through the combing roller and fiber conveying channel into the rotor cohesive trough is regulated to achieve automatic splicing. Furthermore, the splicing process is regulated to optimize the splice shape and structure.

[0029] In practical applications, when the yarn breakage sensor located at the yarn guide plate positioning port detects a yarn breakage, the yarn start-up method is executed as shown in Figure 1, proceeding with steps A to B as follows.

[0030] Step A. Control the cotton feeding roller to reverse and return to the preset length of cotton sliver before stopping. This design is to prevent the combing roller from damaging the fibers. After all the residual fibers in the combing roller and fiber conveying channel are transferred to the rotor, the spinning unit is opened. The combing roller and fiber conveying channel continue to feed the fibers inside into the rotor. The rotor is controlled to stop rotating under the action of the braking structure, and the fibers in the rotor are removed by negative pressure airflow. Then the spinning unit is closed, and at the same time, the pressure roller is disengaged from the yarn feeding roller under the action of the pressure roller cylinder. Then proceed to step B.

[0031] Step B. Control the air-draft rotor spinning machine to obtain the end of the yarn to be wound from the yarn package. After being clamped by the guide roller and the corresponding pressure roller, the yarn is fed into the guide tube of the spinning unit. The winding roller is controlled to rotate, which drives the yarn package to rotate. The yarn is unwound to the storage tube to form seed yarn waiting to be joined.

[0032] In practical applications, step B above includes steps B1 to B5.

[0033] Step B1. First, control the opening of the control valve on the negative pressure pipe of the yarn grabbing arm to connect the negative pressure airflow, so that the yarn grabbing arm maintains suction negative pressure. Then, control the winding roller to reverse and drive the yarn bobbin to rotate, and control the working of the yarn grabbing arm motor to drive the head of the yarn grabbing arm to rotate to the position of the yarn bobbin. The head of the yarn grabbing arm picks up the broken yarn from the yarn bobbin, and after the yarn is detected by the sensor inside the head of the yarn grabbing arm, proceed to step B2.

[0034] Step B2. Control the yarn gripping arm motor to drive the yarn gripping arm head to rotate towards the spinning unit, stretching the yarn on the bobbin. The stretched yarn slides along the yarn slide plate into the yarn slide plate positioning opening. As the yarn gripping arm head continues to rotate towards the spinning unit, the stretched yarn is guided by the yarn guide positioning rod on the pressure roller bracket and moves into the notch positioning position at the front end of the yarn guide positioning rod. Then proceed to step B3.

[0035] Step B3. Control the yarn gripping arm motor to drive the yarn gripping arm head to rotate again towards the yarn package. The two yarn positioning hooks on the back of the yarn gripping arm will hook the stretched yarn, taking over the positioning of the yarn from the yarn guide positioning rod. Then, control the yarn gripping arm motor to drive the yarn gripping arm head to rotate towards the spinning unit. The two yarn positioning hooks will drive the yarn to slide along the yarn guide rod into the space between the yarn guide roller and the corresponding pressure roller. Then, control the yarn guide roller to engage with the pressure roller to hold the yarn. At the same time, stop the middle position of the yarn between the two yarn positioning hooks at the scissor position, and then proceed to step B4.

[0036] Head length L s This refers to the yarn length from the gripping point of the guide roller to the point where the yarn tail is cut to the specified length by the scissors, obtained through measurements of the mechanical structure. After the yarn tail is cut to the specified length, the guide roller will move at a speed V... y1 Reverse t y1 Send the yarn tail to a specific position on the yarn guide tube, using the bottom of the yarn guide tube as a reference: if the yarn tail end goes past the bottom of the yarn guide tube and stays inside the rotor, the yarn tail will be broken and carried away by the negative pressure airflow as the rotor rotates. Therefore, the yarn tail end should not go past the bottom of the yarn guide tube and should not exceed the center position of the yarn guide tube. Since the yarn tail end is in an unheld state, if the tail end goes past the center position, it may be disturbed by the airflow in the workshop or the yarn's own twist, causing the yarn tail to exit the yarn guide tube. Therefore, a safe yarn tail length range should ensure that the yarn tail end is between the center position and the bottom of the yarn guide tube.

[0037] Step B4. Control the scissors to close and cut the yarn located between the two yarn positioning hooks. The cut yarn slides into the yarn guide tube from the top under negative pressure, specifically satisfying the following model:

[0038]

[0039] Controlling the reverse length L of the yarn feeding roller y1 The unwound yarn from the bobbin is used as seed yarn and fed into the yarn guide tube of the spinning unit at the tail yarn stopping position, where V y1 t y1 These represent the reverse length L achieved by controlling the yarn feeding roller. y1 The corresponding reverse rotation speed and reverse rotation duration, L s L represents the length of yarn from the point where the yarn is gripped by the guide roller to the point where the yarn is cut by the scissors. ws L represents the distance L from the gripping point of the yarn feed roller to the top of the yarn feed tube. sg Indicate the length of the yarn guide tube; then proceed to step B5.

[0040] Step B5. Control the winding roller to reverse and drive the yarn package to rotate to continue unwinding the yarn to a preset length. Under the action of negative pressure airflow, the unwound yarn is stored in the yarn storage tube to form seed yarn.

[0041] Based on the execution of the above steps A to B regarding the yarn-generating method, further analysis reveals that, firstly, regarding the yarn-generating length and stopping position of the automatic splicing, by using the tail yarn formed after fixed-length cutting as seed yarn under the action of pressurized airflow into the yarn-leading tube, the action of finding the yarn end from the bobbin yarn in the traditional splicing process can be eliminated.

[0042] During splicing, the yarn feed roller needs to release a certain length of tail yarn to overlap and intersect with the fiber sliver condensed in the rotor at the peeling point, and then wrap and twist to complete the automatic splicing. Therefore, the length of the tail yarn and its position in the yarn feed tube are prerequisites for completing the automatic splicing function.

[0043] (1) Mechanism of tail yarn start-up length

[0044] As can be seen from the automatic head-generating process, the head-generating length L s (mm) refers to the yarn length from point A where the yarn guide roller grips the yarn to point C where the yarn tail is cut to a fixed length by the scissors. As shown in Figure 2, during the automatic yarn start-up process, the two yarn positioning hooks B and D, under the rotation of the yarn gripping arm, position the yarn at the opening of the yarn guide tube. After the scissor cylinder receives the signal, it cuts the yarn to a fixed length from the middle position of the two yarn positioning hooks. Subsequently, under the action of pressurized airflow, the yarn tail enters the yarn guide tube. Therefore, the yarn start-up length is the length L from point A where the yarn guide roller grips the yarn to positioning hook 1. AB (mm) and the length L between positioning hooks 1 and 2BD (mm) is composed of half of the yarn length. Since the positions of the yarn feed roller gripping point A, the scissor position C, and the positioning hooks 1 and 2 are fixed, the yarn tail length L is... s It can be measured by the mechanical structure.

[0045] (2) Position where the tail yarn stops

[0046] The tail yarn dwell position refers to the coordinates of the tail yarn end within the yarn guide tube. The length of overlap and convergence between the seed yarn and the fiber flow condensed in the rotor's condensing tank at the stripping point affects the splicing success rate and quality. Excessive length leads to excessively large thick knots at the splice, while insufficient length results in failure to splice. Therefore, it is necessary to precisely control the length of the tail yarn released when the yarn guide roller reverses its direction. By precisely controlling the tail yarn's dwell position within the yarn guide tube, an initial reference position is provided for the yarn guide roller's reverse release during splicing, thus achieving precise control of the tail yarn release length.

[0047] As can be seen from the automatic head-generating process, at the head-generating length L... s Once determined, the yarn-drawing roller moves at a speed of V. y1 (m / min) Reversing the rollers feeds the yarn tail to a specific position on the guide tube, so the position where the yarn tail stops is related to the length L of the guide roller reversal. y1 (mm) is related to the precise control of the tail yarn dwell position by adjusting the reverse speed and reverse time of the yarn feeding roller.

[0048] Next, we analyze the implementation method of the automatic splicing function of the air-jet spinning machine. Automatic splicing is a spinning technology that utilizes the tail yarn retained in the yarn guide tube and the fiber flow re-condensed in the rotor to overlap, converge and wrap at the stripping point to complete the yarn break splicing and continuously draw the yarn out of the rotor under the action of the winding mechanism.

[0049] The automatic splicing process is shown in Figure 3. After the spinning unit closes, the rotor and carding rollers gradually accelerate to the working speed under the action of the belt; the cotton roller is fed at a set speed V. g (m / min) The start-up feeds the sliver to the gripping point of the carding roller, and then continues to operate at the normal working speed. The sliver is separated into single fibers by the carding roller and airflow channel, and enters the rotor coagulation tank to form a fiber stream; then the yarn guide roller operates at a speed of V. y2 (m / min) The seed yarn is released by reversing, causing it to sink into the rotor's condensation tank under negative pressure airflow and be twisted by the rotor. The continuously rotating tail yarn end intersects and overlaps with the fiber flow for a certain length and becomes entangled with it, breaking the fiber flow and causing it to twist synchronously to form a seed yarn-fiber flow twisted body, completing the splicing. At this time, the winding device is started to continuously draw the yarn out of the rotor and wind it into a cone. Therefore, the key to automatic splicing is to control the overlap length between the seed yarn released by the reversing roller and the fiber flow in the rotor, as well as the twisting time of the seed yarn-fiber flow twisted body.

[0050] (1) Mechanism of overlap length between seed yarn and fiber flow

[0051] The overlap length between the seed yarn and the fiber flow is the length after the seed yarn is released from the initial position (tail yarn dwell position) by the yarn guide roller, enters the rotor cohesion groove through the rotor peeling point, and overlaps with the fiber flow. Therefore, by precisely controlling the tail yarn dwell position and then controlling the reverse speed and reverse time of the yarn guide roller, the seed yarn release length can be controlled, and the overlap length between the seed yarn and the fiber flow can be further regulated.

[0052] (2) Mechanism of seed yarn-fiber flow twisting time

[0053] The twisting time of the seed yarn-fiber flow twister refers to the time from when the seed yarn stops being released by the guide roller to when the winding device starts to guide the yarn after the splicing is completed. During the twisting time, the seed yarn, which sinks into the rotor's condensing tank under the action of negative pressure airflow, breaks the fiber flow in the condensing tank and drives the fibers in the fiber flow to wrap around and twist synchronously, thus completing the splicing. Therefore, the twisting time not only affects the quality of the splice but also the time to start the winding device. The quality of the splice includes parameters such as the twist and thickness of the splice. The greater the twist, the higher the strength of the splice. However, excessive twist will cause a twisting shrinkage effect, which will affect the success rate of the splice. The thickness of the splice is positively correlated with the twisting time. The longer the twisting time, the thicker the splice. However, too short a twisting time will also affect the success rate of the splice. Therefore, the twisting time is fine-tuned within a certain range according to the quality of the splice. After the twisting time is determined, the timing can be started from when the seed yarn stops being released by the guide roller. When the twisting time is reached, the winding device is started to guide the yarn.

[0054] Based on the above analysis, the joint method is further performed as follows: steps C to D.

[0055] Step D. After the spinning unit is closed, control the rotor and carding roller to work, and control the cotton feeding roller to start feeding cotton sliver. The cotton sliver is separated into single fibers through the carding roller and fiber conveying channel, and then conveyed to the coagulation tank in the rotor to coagulate and form a fiber flow, and then proceed to step D.

[0056] Step D. Control the yarn guide roller to reverse, and release the seed yarn from the yarn storage tube. Under the action of negative pressure airflow, the seed yarn sinks into the coagulation tank in the rotor, so that the seed yarn overlaps with the fiber flow in the coagulation tank. The upper limit of the overlap length is the circumference of one rotor coagulation tank. In the overlapping state, the fiber flow condensed in the rotor coagulation tank forms a fiber ring, as shown in Figure 4. Further control the seed yarn and fiber flow to twist and wrap each other to achieve splicing. Then control the yarn guide roller and winding roller to rotate forward, and continuously output the generated yarn and wind it into a bobbin.

[0057] In practical applications, the above-designed joint structure is achieved by first feeding cotton sliver into the cotton roller, which then sends the separated single fibers into the rotor via the combing roller and airflow channel, gradually stacking them in the condensing groove to form fiber rings. Then, the yarn guide roller reverses to release the seed yarn, which passes the rotor's peeling point and enters the rotor's condensing groove. After overlapping the fiber rings in the condensing groove for a specific length, the yarn guide roller stops. As the rotor rotates, the seed yarn and fiber rings intertwine and twist to form a twisted body. When the twisting time is reached, the winding device starts to guide the yarn.

[0058] In practical applications, before the head generation method and the jointing method are executed, the various control parameters are further adjusted in the following manner, and then the designed head generation method and jointing method are executed based on the various control parameters.

[0059] Based on the definition in step D, control the yarn drawing roller at speed V. y2 Reversal time t2, constructing the overlap length L between the seed yarn and the fiber flow in the coagulation tank. q The seed yarn length L is released from the yarn storage tube by the yarn drawing roller. p The relationship between them is as follows:

[0060]

[0061] Among them, L sz L represents the length from the bottom of the yarn guide tube to the rotor peeling point. sg t2 represents the length of the yarn guide tube, and t2 represents the time elapsed from the start of the yarn guide roller reversing to release the seed yarn to the stop time.

[0062] The yarn storage length refers to the length of yarn that remains in the yarn storage tube after being unloaded by the winding roller. After the lead-in roller grasps the yarn, the winding roller moves at a speed V. j Reverse t j After stopping, the unwound yarn is stored in the yarn storage tube under the action of negative pressure airflow; when the yarn guide roller reverses at a set speed, the yarn guide roller reverses and pulls out the yarn stored in the yarn storage tube as seed yarn and releases it to a specific position in the rotor condensing tank, so that the seed yarn and the fiber flow maintain a sufficient overlap length to ensure the quality of the splice.

[0063] To control the winding roller to reverse and drive the yarn bobbin to rotate, the unwinding length L is... j The yarn is stored in the yarn storage tube to form seed yarn, and the following model is constructed:

[0064]

[0065] Among them, L p This indicates the length of seed yarn released from the yarn storage tube by controlling the reversal of the yarn guide roller in step D. V j t jThese represent the control of the winding roller to reverse and drive the yarn bobbin to achieve the unwinding length L. j The reversing speed and reversing time corresponding to the yarn, a1 and a2 respectively represent L j Compared to L p The preset lower limit length and preset upper limit length for upward floating.

[0066] Regarding the control of the twisting time between the seed yarn and the fiber flow, a longer twisting time results in a greater twist of the twisted body and a higher joint strength. However, due to the existence of a critical twist value, excessive twist can lead to over-twisted sections, causing twist shrinkage and making it difficult for the seed yarn and fiber flow to overlap. This results in a weak overlap of the twisted section, affecting the joint diameter, joint strength, and joint success rate. Therefore, while ensuring the joint success rate, the joint twist should be kept as close as possible to the critical twist value to maximize the joint strength.

[0067] Based on the overlap between the seed yarn and the fiber flow in the condenser, according to the yarn linear density ρ y Twist coefficient α t The critical twist is And according to the rotor speed n z Yarn drawing speed V y Then the initial twist T0 = n z / V y Combined with the overlap length L between the seed yarn and the fiber flow in the coagulation tank q With twisting time t3 and splice twist T1, based on the instantaneous twist theory of the inner yarn arm of the spinning cup, the following structure is constructed:

[0068]

[0069] The control of the seed yarn-fiber flow twisting time t3 is based on the twist coefficient α. t and critical twist For reference, the overlap length L between the seed yarn and the fiber flow in the coagulation tank is controlled. q accomplish.

[0070] That is, based on the determination of the position of the yarn tail end connected to the cut point and the yarn wound on the bobbin in the yarn guide tube, combined with the overlap length L between the seed yarn and the fiber flow in the coagulation tank. q According to equation (3), the speed V of the yarn-drawing roller is determined. y2 The reversal time t2 is used to release length L from the yarn storage tube. p The control of the seed yarn is further adjusted according to equation (2), which causes the winding roller to reverse and drive the bobbin to rotate to continue unwinding for a length L. j The yarn is stored in the yarn storage tube to form seed yarn for regulation, and the overlap length L between the seed yarn and the fiber flow in the coagulation tank is used as the basis for regulation. qThe control of twisting time t3 is achieved through equation (4), thereby determining the various control parameters in the head-forming method and the jointing method.

[0071] In practical applications, while executing steps C to D to implement the joint method, the following steps E to F are also included: the method of adjusting the joint morphology and structure based on the joint weight distribution.

[0072] Step E. First, perform a joint weight distribution analysis as follows.

[0073] The joint consists of three parts: the fiber ring superimposed on the rotor cohesive trough from the start of feeding the sliver into the cotton roller until the winding roller reverses and starts to drive the yarn guide; the seed yarn released into the rotor cohesive trough by the yarn storage tube during the release delay t2 when the yarn guide roller reverses; and the newly fed fiber flow into the rotor cohesive trough at the start of yarn guide.

[0074] Regarding the weight of the fiber ring, it is determined by t, which includes the yarn sinking delay t1, from the start of feeding the sliver into the cotton roller until the start of yarn drawing in the winding device. 1b The three time periods are release delay t2 and twisting delay t3.

[0075] The yarn sinking delay t1 refers to the time from when the cotton sliver is fed into the feeding roller to when the guide roller begins to reverse and release the seed yarn. During this time, the feeding roller first feeds the cotton sliver from the return position to the carding roller gripping point at a set speed, and then continues to operate at the normal working speed. Therefore, the yarn sinking delay t1 is calculated from the rapid feed time t. 1a and normal feeding time t 1b composition;

[0076] Release delay t2 refers to the time from the start of the yarn feeding roller reversing to release the seed yarn into the rotor condenser until it stops;

[0077] Twisting delay t3 refers to the twisting time after the seed yarn and fiber ring overlap to form a twisted body, that is, the time from when the seed yarn stops being released by the guide roller to when the guide yarn starts to be drawn.

[0078] According to the speed V of feeding tampons into the cotton roller g , tampon weight ρ s The weight W1 of the fiber ring is obtained as follows;

[0079] W1=(t 1b +t2+t3)×V g ×ρ s (5).

[0080] Regarding the weight of the seed yarn entering the rotor condenser within the release delay t2, ρ is calculated based on the fact that the linear density of the seed yarn is the same as the linear density of the finished yarn. y Combined with the overlap length L between the seed yarn and the fiber flow in the coagulation tankq As follows:

[0081] W2 = L q ×ρ y (6)

[0082] The weight of the seed yarn that enters the rotor condenser within the release delay t2 is W2.

[0083] Regarding the weight of the newly fed fiber stream in the rotor condenser at the start of yarn feeding, based on the fiber coalescence effect in the rotor condenser, it is calculated using the following formula:

[0084]

[0085] The weight W3 of the newly fed fiber stream in the rotor coagulation tank at the start of yarn feeding is obtained.

[0086] Then follow the formula below:

[0087] W = W1 + W2 + W3 = (t 1b +t2+t3)×V1×ρ s +L q ×ρ y +π×D Z ×ρ y (8)

[0088] Obtain the total fiber weight W at the joint.

[0089] Step F. Adjustment of the joint morphology and structure.

[0090] Given that fibers of weight W1 are distributed in the form of fiber rings around the rotor condenser, and considering the fiber coalescence effect in the rotor condenser, the distribution of newly fed fibers of weight W3 around the condenser is linear. Therefore, the linear density of the fiber rings is ρ. r =W / (π×D) Z The maximum linear density of the newly fed fiber stream is set to ρ. y The joint morphology is shown in Figure 5, and the linear density of the seed yarn in the rotor condenser is ρ. y Taking the debonding point inside the rotor as a reference, within the circumference of a coagulation tank, the morphological structure changes from left to right at the joint as follows: coarse section 1 → fine section → coarse section 2. Let the linear densities of coarse section 1, fine section, and coarse section 2 be ρ1, ρ2, and ρ3, respectively, then the structure is as follows:

[0091]

[0092] Based on the overlap length L between the seed yarn and the fiber flow in the coagulation tank qThe control of the twist is based on formula (4). The twisting time t3 is adjusted to control the twist of the joint T1. Combined with the sinking delay t1 and the release delay t2, the maximum and minimum linear density of the joint are controlled to achieve the control of the joint shape and structure. In practical applications, the overlap length is generally about 20mm, and the maximum and minimum linear density are generally 1.4-2 times that of normal yarn.

[0093] Applying the above design scheme to practice, the first step is to adjust the automatic head generation and jointing methods.

[0094] Taking the TQF-K90A rotor spinning machine as an example, the relevant structural parameters in Table 1 can be obtained through measurement. When yarn breakage occurs during normal spinning using the spinning process in Table 2, the relevant yarn breakage and splicing parameters can be obtained by combining the above mathematical model. The specific calculation process is as follows.

[0095] Table 1

[0096]

[0097] Table 2

[0098]

[0099] (1) The length of the tail yarn and its stopping position

[0100] Combining Figure 2 and the model of the yarn tail length and dwell position, it can be seen that a safe yarn tail length range should ensure that the yarn tail end is located between the center of the yarn guide tube and the bottom of the yarn guide tube. Table 1 shows that the yarn tail length L... s = 99.56mm, distance L between the yarn guide roller gripping point and the top of the yarn guide tube ws = 81.3mm, the length of the yarn guide tube is L sg = 83.9mm (mm), according to formula (1), the calculation is based on the end of the yarn stopping at the bottom of the yarn guide tube, that is, the reverse length L of the yarn guide roller. y1 =L sg -(L s -L ws = 65.64mm, set the draft roller to V y1 If the speed is reversed at 10 m / min, then the running time t of the yarn feeding roller is... y1 for:

[0101]

[0102] (2) Seed yarn storage length, release length and overlap length

[0103] According to equation (2), the storage yarn length is related to the release length of the seed yarn, so the release length L of the seed yarn needs to be determined first. pAccording to equation (3), the release length of the seed yarn is related to the release delay t2, and the release delay also directly determines the overlap length L between the seed yarn and the fiber flow within the rotor. q In practical applications, the overlap length of seed yarn cut to a fixed length is generally around 20mm, with the overlap length L... q Substituting 20mm into the calculation, we can see from Table 1 that the length L from the bottom of the yarn guide tube to the rotor peeling point is... sz =19mm, given that the end of the yarn stops at the bottom of the yarn guide tube, the release length of the seed yarn is L. p :

[0104] L p =L q +L sz =20+19=39mm(11)

[0105] Given the seed yarn release length, set the speed at which the guide roller reverses to release the seed yarn to be V. y2 =90m / min, then the seed yarn release delay t2 is:

[0106]

[0107] Given that the general yarn storage length should be 30mm-60mm longer than the release length of the seed yarn, and taking the yarn storage length to be 40mm longer than the release length of the seed yarn, according to formula (2), the yarn storage length L is... j for:

[0108] L j =L p +40=39+40=79mm(13)

[0109] Set the coiled roll with V j If the unwinding speed is 30 m / min, then the reversal time t of the winding roller is... j for:

[0110]

[0111] (3) Twisting time

[0112] During splicing, the rotor speed and yarn feeding speed are both the set values ​​in Table 2, i.e., n z =52000rpm, V y =80m / min, then the initial twist T0 = n z / V y =650 twists / m; the maximum twist coefficient of the warp yarn is obtained from "Spinning Science" as α. t =480, yarn linear density is ρ y =36.4tex, then the twist of the joint should be equal to the twist corresponding to the maximum twist coefficient, that is According to the instantaneous twist theory of the inner yarn arm of the spinning cup in equation (4), the overlap length is known to be L. q =20mm, then the twisting time t3 is:

[0113]

[0114] (4) The shape and structure of the joint

[0115] According to equation (5), combined with the yarn sinking delay t1, release delay t2 = 0.026s, twisting delay t3 = 0.03s, and the diameter D of the rotor coagulation tank... Z =34mm, and the speed at which the cotton roller feeds the swab during splicing is the set value in Table 2, i.e., V g =0.6m / min, the fixed weight of the swab is ρ s =48.5g / 10m, then the linear density ρ of the fiber ring r for:

[0116]

[0117] The maximum linear density of the seed yarn in the coagulation tank is the set yarn linear density ρ. y =36.4tex; the maximum linear density of the newly fed fiber stream is the set yarn linear density ρ y = 36.4 tex; According to equation (9), the overlap length is known to be L. q =20mm, then the linear densities ρ1(tex), ρ2(tex), and ρ3(tex) corresponding to detail 1, thick section, and detail 2 in the joint structure of Figure 5 are respectively:

[0118]

[0119] By regulating t in formula (17) 1b This allows for the adjustment of the linear density of the two detailed sections and one coarse section of the joint, thereby enabling control over the joint's shape. If t is taken... 1b =0.005s, then the maximum linear density of the splice ρ2 = 70.9tex, and the minimum linear density ρ1 = ρ3 = 64tex. Given that the unwinding length of the feeding roller when the yarn breaks is 13mm, and that the feeding roller starts rapidly at a speed of 4m / min during automatic splicing to feed the sliver to the carding roller gripping point, then t 1a =13 / 4000×60=0.195s, then the delay time for yarn sinking t1=t 1a +t 1b =0.2s.

[0120] For the air-suction rotor spinning machine structure shown in Figures 6 to 11, based on the calculated yarn breakage and splicing parameters, the yarn breakage sensor installed at the yarn guide plate positioning port detects yarn breakage. In actual application, the yarn breakage method is first executed as follows: step A and steps B1 to B5. Then, the splicing method is executed as follows: steps I to III.

[0121] Step A. When yarn 4 breaks, the spinning unit 25 is opened by pushing the cylinder. The rotor stops rotating under the action of the brake structure. The fibers inside the rotor are cleaned by negative pressure airflow, so that there are no residual fibers inside the rotor. At the same time, the pressure roller 18 is disengaged from the yarn guide roller 17 by the action of the pressure roller cylinder 22. The spinning unit 25 is closed by the retraction of the cylinder. At this time, the rotor is disengaged from the brake block and gradually accelerates to the working speed of 52,000 rpm with the transmission belt. The carding roller also gradually accelerates to the working speed of 8,000 rpm with the belt.

[0122] Step B1. The control valve on the negative pressure pipe 15 of the yarn grabbing arm is opened, and the yarn grabbing arm 11 is connected to the negative pressure airflow. The yarn grabbing arm 11 maintains a stable suction of negative pressure. The lifting rod 6 is in the raised position under the push of the cylinder. The winding roller 5 rotates in the opposite direction at a speed of 30m / min, driving the yarn package 3 to rotate. The head end of the yarn grabbing arm 11 rotates to the yarn package 3 under the drive of the yarn grabbing arm motor 13, and picks up the broken ends of the yarn 4 on the yarn package 3, and proceeds to step B2.

[0123] Step B2: Control the operation of the yarn gripping arm motor to drive the head of the yarn gripping arm 11 to rotate towards the spinning unit 25, stretching the yarn 4 on the yarn package 3, so that the stretched yarn 4 slides along the yarn slide plate 9 into the positioning port 36 of the yarn slide plate 9, and as the head of the yarn gripping arm 11 continues to rotate towards the spinning unit 25, the stretched yarn 4 is guided by the yarn guide positioning rod 20 on the pressure roller bracket 19 and moves into the notch positioning position at the front end of the yarn guide positioning rod 20, and then proceeds to step B3.

[0124] Step B3. Control the yarn gripping arm motor to drive the head of the yarn gripping arm 11 to rotate again towards the yarn package 3. The two yarn positioning hooks 12 on the back of the yarn gripping arm 11 hook the stretched yarn 4, taking over the positioning of the yarn 4 from the yarn guide positioning rod 20. Then control the yarn gripping arm motor to drive the head of the yarn gripping arm 11 to rotate towards the spinning unit 25. The two yarn positioning hooks 12 drive the yarn 4 to slide along the yarn guide rod 23 into the space between the yarn guide roller 17 and the corresponding pressure roller 18. Then the pressure roller cylinder 22 is de-energized. Under the pressure of the pressure roller torsion spring 21, the yarn guide roller 17 and the pressure roller 18 are engaged to hold the yarn 4. At the same time, the middle position of the yarn 4 between the two yarn positioning hooks 12 is stopped at the scissor 27 position. Then proceed to step B4.

[0125] Step B4. Control the scissor cylinder 28 to push the scissors 27 to close and cut the yarn 4 located between the two yarn positioning hooks 12. The cut yarn 4 slides from the top of the yarn guide tube 26 into the yarn guide tube 26 under negative pressure. Then the scissor cylinder 28 retracts to reset the scissors 27. Then control the yarn guide roller 17 to rotate 65.64 mm at a speed of 10 m / min so that the yarn 4 reaches the bottom position of the yarn guide tube 26, and proceed to step B5.

[0126] Step B5. Control the winding roller 5 to drive the yarn package 3 to rotate in the opposite direction at a speed of 30m / min. The yarn package 3 has a storage length of 79mm, and under the action of negative pressure airflow, the unwound yarn 4 is stored in the yarn storage tube to form seed yarn.

[0127] Step I. After the spinning unit is closed, control the rotor and carding roller to work. First, control the cotton feed roller to start and feed the cotton sliver to the carding roller gripping point at a speed of 4 m / min. Then, feed the cotton sliver continuously at a working speed of 0.6 m / min. When the sand settling delay t1 = 0.2 s, proceed to Step II.

[0128] Step II. Control the yarn guide roller to quickly reverse 39mm at a speed of 90m / min, so that the tail end of the yarn 4 enters the rotor cohesion tank and twists with the pre-formed fiber flow. When the twisting time t3 = 0.03s is reached, the yarn guide roller 17 starts to rotate forward at a working speed of 80m / min. At the same time, the winding roller 5 also drives the yarn package 3 to wind. The lifting rod 6 falls under the action of the cylinder, so that the yarn 4 slides into the transverse moving mouth, realizing the continuous output of the yarn. This completes the automatic yarn production and splicing action of the entire device.

[0129] The above technical solution is based on the structure of a spinning machine. It designs a time-series automated operation for the yarn-grabbing arm structure, efficiently locating the yarn tail from the yarn package and positioning it at specific locations on the spinning machine structure. After being cut to a fixed length, it enters the yarn guide tube with negative pressure airflow, achieving automatic yarn head generation. Then, cotton sliver is fed into the rotor's condensing tank via the cotton roller to form a fiber flow, and the seed yarn is fed into the rotor's condensing tank by controlling the yarn guide roller. The seed yarn and fiber flow overlap, performing mutual twisting and wrapping to achieve splicing. During the design and execution, precise speed and time control calculations are used to coordinate the control between various device structures, adjusting the overlap length and twisting time of the seed yarn and fiber flow, and further controlling the morphology and mechanical properties of the seed yarn-fiber flow twisted body. This improves the quality and efficiency of splicing broken yarn in practical applications.

[0130] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An automatic yarn-forming splicing method based on a vacuum-type airflow rotor spinning machine, characterized in that: Based on the yarn breakage sensor installed at the yarn guide plate positioning port, the yarn breaks, and the PLC coordinates the actions of each mechanism of the rotor spinning to execute the yarn breakage and start-up method as follows: Steps A to B. Step A. Control the cotton feeding roller to reverse and return to the preset length of cotton sliver and then stop. During this period, all residual fibers in the combing roller and fiber conveying channel are transferred to the rotor. The spinning unit is opened under the action of the cylinder, and the rotor stops rotating under the action of the brake structure. The fibers in the rotor are cleaned by the negative pressure airflow. Then the spinning unit is closed by the action of the cylinder. At the same time, the pressure roller is disengaged from the yarn feeding roller under the action of the pressure roller cylinder. Then proceed to step B. Step B. Control the air-assisted rotor spinning machine to obtain the end of the broken yarn from the yarn package. After being clamped by the guide roller and the corresponding pressure roller, the yarn is fed into the guide tube of the spinning unit. The winding roller is controlled to rotate, which drives the yarn package to rotate and unwind the yarn to the storage tube to form seed yarn waiting to be joined.

2. The automatic yarn-forming and splicing method for a rotary spinning machine based on a vacuum-type airflow spinning machine according to claim 1, characterized in that: Based on the winding mechanism, the broken yarn is unwound as seed yarn into the rotor coagulation tank. The fiber flow formed by the cotton sliver fed by the cotton roller and entering the rotor coagulation tank through the combing roller and fiber conveying channel is overlapped and controlled to achieve automatic splicing function. The splicing method is as follows: steps C to D. Step C. After the spinning unit is closed, control the rotor and carding roller to work, and control the cotton feeding roller to start feeding cotton sliver. The cotton sliver is separated into single fibers through the carding roller and fiber conveying channel, and then conveyed to the coagulation tank in the rotor to coagulate and form a fiber flow, and then proceed to step D. Step D. Control the yarn guide roller to reverse, and release the seed yarn from the yarn storage tube. Under the action of negative pressure airflow, the seed yarn sinks into the coagulation tank in the rotor cup, overlaps with the fiber flow in the coagulation tank, and twists and wraps with each other to achieve splicing. Then control the yarn guide roller and winding roller to rotate forward, and continuously output the generated yarn and wind it into a cone.

3. The automatic yarn-forming and splicing method for a rotary spinning machine based on a vacuum-type airflow spinning machine according to claim 1, characterized in that: Step B includes the following steps B1 to B5; Step B1. First, control the opening of the control valve on the negative pressure pipe of the yarn grabbing arm to connect the negative pressure airflow, so that the yarn grabbing arm maintains the suction negative pressure. Then, control the winding roller to reverse and drive the yarn package to rotate, and control the working of the yarn grabbing arm motor to drive the head of the yarn grabbing arm to rotate to the yarn package position. The head of the yarn grabbing arm picks up the broken yarn from the yarn package, and after the yarn is detected by the sensor inside the head of the yarn grabbing arm, proceed to step B2. Step B2. Control the yarn grabbing arm motor to drive the head of the yarn grabbing arm to rotate towards the spinning unit, stretch the yarn on the bobbin, so that the stretched yarn slides into the positioning opening of the yarn slide plate along the yarn slide plate, and as the head of the yarn grabbing arm continues to rotate towards the spinning unit, the stretched yarn is guided by the yarn guide positioning rod on the pressure roller bracket and moves into the notch positioning position at the front end of the yarn guide positioning rod, and then proceeds to step B3; Step B3. Control the yarn gripping arm motor to drive the yarn gripping arm head to rotate again towards the yarn package. The two yarn positioning hooks on the back of the yarn gripping arm will hook the stretched yarn and take over the positioning of the yarn from the yarn guide positioning rod. Then, control the yarn gripping arm motor to drive the yarn gripping arm head to rotate towards the spinning unit. The two yarn positioning hooks will drive the yarn to slide along the yarn guide rod into the space between the yarn guide roller and the corresponding pressure roller. Then, control the yarn guide roller to mesh with the pressure roller to hold the yarn. At the same time, stop the middle position of the yarn between the two yarn positioning hooks at the scissor position, and then proceed to step B4. Step B4. Control the scissors to close and cut the yarn located between the two yarn positioning hooks. The cut yarn slides from the top of the yarn guide tube into the yarn guide tube under negative pressure, and then proceeds to step B5. Step B5. Control the winding roller to reverse and drive the yarn package to rotate to continue unwinding the yarn to a preset length. Under the action of negative pressure airflow, the unwound yarn is stored in the yarn storage tube to form seed yarn.

4. The automatic yarn-forming and splicing method for a rotary spinning machine based on a vacuum-type airflow spinning machine according to claim 3, characterized in that: In step B4, the following model is satisfied: Control the reverse length L of the yarn feeding roller y1 The unwound yarn from the bobbin is used as seed yarn and fed into the yarn guide tube of the spinning unit at the tail yarn stopping position, where V y1 t y1 These represent the reverse length L achieved by controlling the yarn feeding roller. y1 The corresponding reverse rotation speed and reverse rotation duration, L s L represents the length of yarn from the point where the yarn is gripped by the guide roller to the point where the yarn is cut by the scissors. ws L represents the distance L from the gripping point of the yarn feed roller to the top of the yarn feed tube. sg This indicates the length of the yarn guide tube.

5. The automatic yarn-forming and splicing method for a rotary spinning machine based on a vacuum-type airflow spinning machine according to claim 2, characterized in that: In step D, the yarn guide roller is reversed, and the seed yarn in the yarn storage tube is released and sinks into the coagulation tank in the rotor under the action of negative pressure airflow, so that the seed yarn overlaps with the fiber flow in the coagulation tank, and the upper limit of the overlap length is the circumference of one rotor coagulation tank. In the overlapping state, the fiber flow condensed in the rotor coagulation tank forms a fiber ring.

6. The automatic yarn-forming splicing method for a rotary spinning machine based on a vacuum-type airflow spinning machine according to claim 5, characterized in that, Before the head-generating method and the jointing method are executed, the various control parameters are adjusted as follows: Based on the definition in step D, control the yarn drawing roller at speed V. y2 Reversal time t2, constructing the overlap length L between the seed yarn and the fiber flow in the coagulation tank. q The seed yarn length L is released from the yarn storage tube by the yarn drawing roller. p The relationship between them is as follows: Among them, L sz L represents the length from the bottom of the yarn guide tube to the rotor peeling point. sg t2 represents the length of the yarn guide tube, and t2 represents the time elapsed from the start of the yarn guide roller reversing to release the seed yarn to the stop time. To control the winding roller to reverse and drive the yarn bobbin to rotate, the unwinding length L is... j The yarn is stored in the yarn storage tube to form seed yarn, and the following model is constructed: Among them, L p This indicates the length of seed yarn released from the yarn storage tube by controlling the reversal of the yarn guide roller in step D. V j t j These represent the control of the winding roller to reverse and drive the yarn bobbin to achieve the unwinding length L. j The reversing speed and reversing time corresponding to the yarn, a1 and a2 respectively represent L j Compared to L p The preset lower limit length and preset upper limit length for upward movement; Based on the overlap between the seed yarn and the fiber flow in the condenser, according to the yarn linear density ρ y Twist coefficient α t The critical twist is And according to the rotor speed n z Yarn drawing speed V y Then the initial twist T0 = n z / V y Combined with the overlap length L between the seed yarn and the fiber flow in the coagulation tank q With twisting time t3 and splice twist T1, based on the instantaneous twist theory of the inner yarn arm of the spinning cup, the following structure is constructed: The control of the seed yarn-fiber flow twisting time t3 is based on the twist coefficient α. t and critical twist T αt For reference, the overlap length L between the seed yarn and the fiber flow in the coagulation tank is controlled. q accomplish; That is, based on the determination of the position of the yarn tail end connected to the cut point and the yarn wound on the bobbin in the yarn guide tube, combined with the overlap length L between the seed yarn and the fiber flow in the coagulation tank. q According to equation (3), the speed V of the yarn-drawing roller is determined. y2 The reversal time t2 is used to release length L from the yarn storage tube. p The control of the seed yarn is further adjusted according to equation (2), which causes the winding roller to reverse and drive the bobbin to rotate to continue unwinding for a length L. j The yarn is stored in the yarn storage tube to form seed yarn for regulation, and the overlap length L between the seed yarn and the fiber flow in the coagulation tank is used as the basis for regulation. q The control of twisting time t3 is achieved through equation (4), thereby determining the various control parameters in the head-forming method and the jointing method.

7. The automatic yarn-forming splicing method for a rotary spinning machine based on a vacuum-type airflow spinning machine according to claim 6, characterized in that, The execution of steps C to D of the joint method also includes steps E to F as follows: A method for adjusting the joint morphology and structure based on the joint weight distribution. Step E. First, perform a joint weight distribution analysis as follows: The joint consists of three parts: the fiber ring superimposed on the rotor cohesive trough from the start of feeding cotton sliver into the feed roller until the winding roller reverses and starts to drive the yarn guide; the seed yarn released into the rotor cohesive trough by the yarn storage tube during the release delay t2; and the newly fed fiber flow into the rotor cohesive trough at the start of yarn guide. Regarding the weight of the fiber ring, it is determined by t, which includes the yarn sinking delay t1, from the start of feeding the sliver into the cotton roller until the start of yarn drawing in the winding device. 1b The three time periods are: release delay t2 and twisting delay t3; The yarn sinking delay t1 refers to the time from when the cotton sliver is fed into the feeding roller to when the guide roller begins to reverse and release the seed yarn. During this time, the feeding roller first feeds the cotton sliver from the return position to the carding roller gripping point at a set speed, and then continues to operate at the normal working speed. Therefore, the yarn sinking delay t1 is calculated from the rapid feed time t. 1a and normal feeding time t 1b composition; Release delay t2 refers to the time from the start of the yarn feeding roller reversing to release the seed yarn into the rotor condenser until it stops; Twisting delay t3 refers to the twisting time after the seed yarn and fiber ring overlap to form a twisted body, that is, the time from when the seed yarn stops being released by the guide roller to when the guide yarn starts to be drawn. According to the speed V of feeding tampons into the cotton roller g , tampon weight ρ s The weight W1 of the fiber ring is obtained as follows; W1=(t 1b +t2+t3)×V g ×ρ s (5) Regarding the weight of the seed yarn entering the rotor condenser within the release delay t2, ρ is calculated based on the fact that the linear density of the seed yarn is the same as the linear density of the finished yarn. y Combined with the overlap length L between the seed yarn and the fiber flow in the coagulation tank q As follows: W2=L q ×ρ y (6) The weight of the seed yarn entering the rotor condenser within the release delay t2 is W2; Regarding the weight of the newly fed fiber stream in the rotor condenser at the start of yarn feeding, based on the fiber coalescence effect in the rotor condenser, it is calculated using the following formula: The weight W3 of the newly fed fiber stream in the rotor coagulation tank at the start of yarn feeding is obtained; Then follow the formula below: W=W1+W2+W3=(t 1b +t2+t3)×V1×ρ s +L q ×ρ y +π×D Z ×ρ y (8) Obtain the total fiber weight W at the joint; Step F. Adjustment of joint morphology and structure: Given that fibers of weight W1 are distributed in the form of fiber rings around the rotor condenser, and considering the fiber coalescence effect in the rotor condenser, the distribution of newly fed fibers of weight W3 around the condenser is linear. Therefore, the linear density of the fiber rings is ρ. r =W / (π×D) Z The maximum linear density of the newly fed fiber stream is set to ρ. y And combined with the linear density of the seed yarn in the rotor condenser as ρ y Taking the debonding point inside the rotor as a reference, within the circumference of a coagulation tank, the morphological structure changes from left to right at the joint as follows: coarse section 1 → fine section → coarse section 2. Let the linear densities of coarse section 1, fine section, and coarse section 2 be ρ1, ρ2, and ρ3, respectively, then the structure is as follows: Based on the overlap length L between the seed yarn and the fiber flow in the coagulation tank q According to formula (4), the twisting time t3 is adjusted to control the twist of the joint T1. Then, combined with the sinking delay t1 and the release delay t2, the maximum and minimum linear density of the joint are controlled to achieve the regulation of the joint shape and structure.

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