Method for automatic splicing in rotor spinning based on regulating the length of the tail yarn

Abstract

This invention designs an automatic splicing method for rotor spinning based on controlling the tail length of the yarn. Addressing yarn breakage caused by temporary stops or power outages during rotor spinning, a backup power supply controls the operation of various components of the rotor spinning machine. By precisely calculating the spinnable yarn length of residual fibers after passing through the rotor, the system guides the orderly shutdown of mechanisms such as the guide roller and winding roller, ensuring the broken yarn tail ends stop within the twist stopper's guide tube, thus achieving automatic tail retention during shutdown. Upon restarting or when power is restored, the doffing mechanism unwinds the broken yarn as seed yarn into the rotor's cohesive groove. There, it overlaps and twists with the fiber flow formed by the sliver fed by the cotton roller through the combing roller and fiber conveying channel, completing the splicing action. Furthermore, the linear density, twist, and strength of the seed yarn-fiber flow twisted body are adjusted to improve the splicing success rate, achieving high-quality automatic splicing and improving enterprise production efficiency.

Description

Technical Field

[0001] This invention relates to a method for automatic splicing of rotor spinning based on adjusting the tail length of the yarn, belonging to the field of spinning automation technology. Background Technology

[0002] During rotor spinning, temporary stops or power outages can cause yarn breakage. To resume spinning, the following steps are necessary: ​​① Clean the fibers remaining in the spinneret; ② Locate the broken yarn from the bobbin, pull out a specific length of yarn, pass it through the guide roller's gripping point and into the guide twist-stop tube, where it extends to the stripping point inside the rotor under negative pressure airflow; ③ Feed the cotton sliver into the cotton roller, where the separated single fibers are fed into the rotor through the carding roller and airflow channel, coalescing to form a new fiber sliver, which intersects with the seed yarn located at the stripping point inside the rotor and wraps around it to complete the splice; ④ Start the winding mechanism to resume normal spinning. Splicing methods include manual splicing, semi-automatic splicing, and fully automatic splicing.

[0003] For temporary shutdowns and power outages, existing technical solutions have the following problems: ① The yarn tail after breakage is wound onto the yarn package, requiring re-splitting to continue spinning; ② After breakage, how to adjust the winding mechanism not only to keep the yarn tail in the yarn guide twisting tube, but also to design the tail length to ensure that the tail yarn and the newly condensed fiber sliver can overlap and intersect at the rotor peeling point to form a splice. Therefore, the efficiency of existing technologies in application is not high. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an automatic splicing method for rotor spinning based on adjusting the tail length of the yarn. The invention adopts a brand-new design and efficiently implements the designed stop tail length retention method and splicing method, effectively solving the problem of yarn breakage during stop in rotor spinning and improving splicing efficiency.

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

[0006] 1. Inventing a method for retaining yarn ends during power outages in rotor spinning: In order to eliminate the need to find broken ends from the yarn cones and start new yarn in the traditional splicing process, the UPS power supply after a power outage controls the orderly stopping of each component of the rotor spinning machine, so that the broken yarn ends are retained in the yarn guide tube of the twist stopper to complete the function of retaining yarn ends. When the machine is restarted, it will serve as the tail yarn to lay the foundation for automatic splicing.

[0007] 2. Invention of a method for controlling the position of the yarn tail based on the change of the tail length: In order to accurately control the position of the yarn tail, for different rotor spinning equipment, different spinning raw materials and processes, the weight of the fibers remaining in the spinning machine after power failure and the length of the yarn that can be spun are calculated. By designing the tail length, the position of the yarn tail in the yarn guide twisting tube can be precisely controlled.

[0008] 3. Invent 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.

[0009] 4. Invent a method for automatic splicing of seed yarn and fiber flow in the rotor: By coordinating the changes in the start-up time of the cotton roller, the release length and time of the seed yarn, and the winding time of the winding drum, the overlap length and twisting time of the seed yarn and fiber flow are controlled, and the morphological structure and mechanical properties of the seed yarn-fiber flow twisted body are further controlled to improve the quality of splicing.

[0010] The automatic splicing method for rotor spinning based on adjusting the tail yarn length described in this invention has the following technical advantages compared with the prior art:

[0011] This invention designs an automatic yarn splicing method for rotor spinning based on controlling the tail length of the yarn. Addressing the issue of yarn breakage due to temporary stops or power outages during rotor spinning, a UPS (Uninterruptible Power Supply) provides backup power to the entire machine, controlling the actions of various components. By precisely calculating the spinnable yarn length of residual fibers after passing through the rotor, a program guides the orderly shutdown of mechanisms such as the guide roller and winding roller, ensuring the broken yarn tail stops within the twist stopper's guide tube, thus achieving automatic yarn tail retention during shutdown. Then, upon restarting... When the machine is started or power is restored, the control mechanism unwinds the broken yarn as seed yarn into the rotor's condensing trough. This yarn overlaps and twists with the fiber stream formed by the cotton sliver fed into the rotor's condensing trough via the carding rollers and fiber conveying channel, completing the splicing action. Based on the tail yarn's dwell position using the automatic tail-keeping function, the overlap length and twisting time of the seed yarn and fiber stream are precisely calculated to further adjust parameters such as linear density, twist, and strength of the seed yarn-fiber stream twisted body, improving the splicing success rate and achieving high-quality automatic splicing. This enables efficient and automated completion of automatic tail-keeping and automatic splicing functions during temporary stops or power outages in rotor spinning, improving enterprise production efficiency. Attached Figure Description

[0012] Figure 1 This is a flowchart of the shutdown and tail-retention method in the design of this invention;

[0013] Figure 2 This is a schematic diagram of the fibers that remain inside the rotor spinner after a power outage, as designed and applied in this invention.

[0014] Figure 3a It corresponds to Figure 2 A schematic diagram showing the yarn lengths corresponding to the continuous spinning process at various positions in the middle;

[0015] Figure 3b It corresponds to Figure 2 A diagram showing the corresponding yarn lengths at various locations after a power outage and machine shutdown.

[0016] Figure 4 This is a flowchart of the joint method in the design of this invention;

[0017] Figure 5 This invention relates to the speed distribution of different yarn formation paths within the rotor spinner.

[0018] Figure 6 This is a schematic diagram of the force analysis of the fiber on the sliding surface inside the rotating cup in this invention.

[0019] Figure 7 This is a schematic diagram of the fiber loop linear density distribution within the rotor cup condenser.

[0020] Figure 8 It is quality A schematic diagram of fiber length distribution in a rotary cup condenser;

[0021] Figures 9 to 12 Schematic diagram of the overlapping structure of four types of seed yarn and fiber flow;

[0022] Figure 13 For the corresponding Figure 12 A schematic diagram of the joint structure morphology analysis;

[0023] Figure 14 This is a schematic diagram of the mechanism of the TQFK86 rotor spinning machine.

[0024] Among them, 1. yarn bobbin, 2. winding assembly, 3. yarn storage tube, 4. yarn guide roller, 5. yarn guide motor, 6. yarn guide roller, 7. electronic yarn clearer, 8. spinning machine. Detailed Implementation

[0025] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0026] To address the problems of the prior art, the present invention adopts the following technical solution:

[0027] 1. Inventing a method for retaining yarn ends during power outages in rotor spinning: In order to eliminate the need to find broken ends from the yarn cones and start new yarn in the traditional splicing process, the UPS power supply after a power outage controls the orderly stopping of each component of the rotor spinning machine, so that the broken yarn ends are retained in the yarn guide tube of the twist stopper to complete the function of retaining yarn ends. When the machine is restarted, it will serve as the tail yarn to lay the foundation for automatic splicing.

[0028] 2. Invention of a method for controlling the position of the yarn tail based on the change of the tail length: In order to accurately control the position of the yarn tail, for different rotor spinning equipment, different spinning raw materials and processes, the weight of the fibers remaining in the spinning machine after power failure and the length of the yarn that can be spun are calculated. By designing the tail length, the position of the yarn tail in the yarn guide twisting tube can be precisely controlled.

[0029] 3. Invent 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.

[0030] 4. Invent a method for automatic splicing of seed yarn and fiber flow in the rotor: By coordinating the changes in the start-up time of the cotton roller, the release length and time of the seed yarn, and the winding time of the winding drum, the overlap length and twisting time of the seed yarn and fiber flow are controlled, and the morphological structure and mechanical properties of the seed yarn-fiber flow twisted body are further controlled to improve the quality of splicing.

[0031] Specifically, the automatic splicing method for rotor spinning designed in this invention is based on the control of the tail yarn length. After the rotor spinning is powered off, the backup power supply and PLC control the operation of each mechanism of rotor spinning to achieve the automatic head-keeping function by adjusting the tail yarn length and tail yarn position. After the power is turned on and spinning is restarted, the automatic splicing function is achieved by controlling the overlap process between the new fiber ring formed in the rotor coagulation tank and the tail yarn. Furthermore, the splicing morphology and structure are optimized by controlling the overlap process.

[0032] The design of the automatic tail-keeping mechanism and automatic splicing method for rotor spinning machine power failure shutdown is as follows.

[0033] 1. Mechanism for automatic tail retention during rotor spinning machine shutdown in the event of power failure

[0034] Automatic tail-keeping is designed to prevent sudden power outages during normal operation of equipment. With the help of generators in some parts and the UPS uninterruptible power supply, the entire machine is controlled to stop in an orderly manner, and the position of the yarn tail after spinning is precisely controlled, creating favorable conditions for automatic reconnection of the equipment when power is restored.

[0035] like Figure 1As shown, after a power outage, the equipment is powered by a mechanism with high inertia and rotational characteristics, such as a waste removal fan, or by a UPS uninterruptible power supply to maintain the tail-end function of the rotor spinning machine. After a power outage, the carding roller and rotor stop naturally due to their own inertia. Based on the UPS uninterruptible power supply, the feed roller, yarn guide roller, and winding roller are reduced to 30%~60% of their working speed. When a stop feeding command is received, the feed roller instantly reverses and breaks the cotton sliver at the carding roller spacing point. The fibers remaining in the carding roller, airflow channel, and rotor are transformed into yarn under the action of the carding roller, airflow channel, rotor, and yarn guide roller. By appropriately controlling the tail-end length of the winding mechanism, not only can the yarn tail end be kept in the yarn guide twist-stop tube, but the position of the tail yarn in the yarn guide twist-stop tube can also be precisely controlled. Automatic tail-end length lays the foundation for automatic splicing.

[0036] 2. The design meets the requirements for the tail yarn length and dwell position of the automatic splicer.

[0037] By retaining the yarn tail formed by residual fibers in the rotor spinning process after power failure within the yarn guide twist-stop tube under the action of the winding mechanism, the action of finding the yarn end from the package yarn in the traditional splicing process can be eliminated. During splicing, the guide roller needs to release a certain length of the tail yarn to overlap and intersect with the newly condensed fiber flow in the rotor at the peeling point, and then wrap and twist it to complete the automatic splicing. Therefore, the tail yarn length and the position of its dwell are prerequisites for completing the splicing function. At the same time, after the splicing is completed, starting the winding mechanism to continuously draw the yarn out of the rotor to complete the winding is an auxiliary action that must be completed by the automatic splicing.

[0038] (1) Mechanism of tail length retention

[0039] like Figure 2 As shown, after the power is cut off, the cotton feed roller instantly reverses and breaks the cotton sliver at the carding roller spacing point g. The tail length is the length of the yarn remaining after the fibers in the carding roller, airflow channel, and rotor are drawn out and held at a specific position by the action of the carding roller, airflow channel, rotor, and guide roller. Let it be denoted as . (mm). The spinnable yarn length of the residual fibers is also from... Figure 2 The length of yarn that fibers within the section from the center carding roller spacing point g to the inner peeling point p of the rotor can be converted into.

[0040] by Figure 2 The reference point is the gripping point 'a' of the yarn roller, as follows: Figure 3a In the continuous spinning process shown, the yarn within the distance from the rotor peeling point p to the yarn guide roller gripping point a is normal yarn. Let this distance be... And it can be obtained according to the mechanical structure dimensions; after power failure, such as Figure 3bAs shown, the lead-in roller, under the action of the UPS uninterruptible power supply, twists and shapes the fibers remaining in the GP section of the spinning machine and leads them out, continuing to operate for a length of... Then stop, at this time Figure 3a The yarn at point a, where the yarn feed roller grips, reaches point q, which is... The length is equal to Therefore, the yarn tail winding length is the length of continuous operation of the yarn guide roller after a power outage. This means calculating the distance from the carding roller gap point g, through the carding roller, fiber conveying channel, rotor, to the rotor peeling point p. Figure 2 The length of the spinnable yarn and its dwell position of the fiber within the middle path (gp).

[0041] (2) Position where the tail yarn stops

[0042] The tail yarn dwell position refers to the coordinates of the tail yarn end within the yarn guide twist-stop tube. Analysis of the overlap and convergence length of the seed yarn and the fiber flow condensed in the rotor's condensation tank at the peeling point reveals that an excessively long overlap leads to an excessively large thick section at the splice, while an excessively short overlap prevents proper splicing. Therefore, a suitable tail yarn release length is crucial for splicing success rate and quality. Precisely controlling the tail yarn's dwell position within the twist-stop tube after power failure provides an initial reference position for the yarn guide roller's release of the tail yarn during splicing, allowing for further precise control of the released tail yarn length.

[0043] As can be seen from the above (1) interruption of the tail yarn retention length mechanism, the dwell position of the tail yarn is related to the length of continuous operation of the guide roller. Related to length The length of the fiber sliver remaining in the spinning machine after a power outage is related to the weight of the fiber sliver and the speed of the lead-in roller. Therefore, it is necessary to analyze the speed distribution of the fiber sliver remaining in the spinning machine at different stages after a power outage, establish a mathematical model of the speed at different stages and the speed of the lead-in roller, and then calculate the length. Then, by adjusting the speed of the guide roller, the precise control of the tail yarn's stopping position can be achieved.

[0044] 3. Implementation method of automatic splicing function in rotor spinning

[0045] Automatic splicing in rotor spinning 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 around each other at the stripping point, completing the yarn breakage splicing and continuously drawing the yarn out of the rotor under the action of the winding mechanism.

[0046] Automatic connector process as follows Figure 4As shown, after power is supplied, the rotor and carding rollers start at set values. The winding roller reverses and unwinds a specific length of yarn, which is stored in the yarn storage tube under negative pressure airflow. The feeding roller starts at a set speed to feed in the sliver, which is separated into single fibers by the carding roller and airflow channel and enters the rotor's cohesive groove to form a fiber flow. Then, the lead roller releases the seed yarn, which sinks into the rotor's cohesive groove under negative pressure airflow and is twisted by the rotor. The continuously rotating tail yarn ends overlap with the fiber flow for a certain length and become entangled, 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 mechanism starts 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 lead roller and the fiber flow in the rotor, as well as the twisting time of the seed yarn-fiber flow twisted body.

[0047] (1) Mechanism of overlap length between seed yarn and fiber flow

[0048] The overlap length between the seed yarn and the fiber flow is the length of the seed yarn released by the guide roller from the initial position (the position where the tail yarn stays after power failure), which enters the rotor cohesion tank through the rotor peeling point and overlaps with the fiber flow. Therefore, by precisely controlling the position of the tail yarn end that is automatically retained after power failure, and by controlling the reverse speed and reverse time of the guide roller, the release length of the seed yarn can be controlled, and the overlap length between the seed yarn and the fiber flow can be further adjusted.

[0049] (2) Mechanism of seed yarn-fiber flow twisting time

[0050] 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 mechanism 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 when the winding mechanism is started. 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 mechanism is started to guide the yarn.

[0051] Based on the above mechanism construction and analysis, the automatic splicing method for rotor spinning designed in this invention, which achieves automatic splicing of rotor spinning based on adjusting the tail length of the tail yarn, is designed for rotor spinning machines with backup power supply. In practical applications, the method includes a power-off triggered shutdown tail-keeping method that executes steps A to B, and a power-on triggered splicing method that executes the following steps. To the steps .

[0052] Step A. The carding roller and rotor stop naturally due to their own inertia. At the same time, the components of the rotor spinning machine are stopped in an orderly manner based on backup power such as UPS uninterruptible power supply. Specifically, power is supplied to the cotton roller, yarn guide roller and winding roller, and the cotton roller, yarn guide roller and winding roller are controlled to decelerate to 30%~60% of their original working speed and continue to work. Then proceed to step B.

[0053] The above mechanism analysis shows that in the rotor spinning continuous spinning process, the fiber velocity distribution varies at different stages due to the different yarn formation paths. Let the velocities at each stage be: the linear velocity of the feed roller is... (m / min), fiber optic channel inlet is (m / min), the fiber conveying channel outlet speed is (m / min), the linear velocity of the condensation tank is (m / min), the linear velocity of the yarn guide roller after power failure is (m / min), the speed of the combing roller is (rpm), the rotor speed is (rpm) can be divided into, for example Figure 5 The stages shown.

[0054] (1) After power failure, in the cotton feeding area, the fibers within the cotton feeding-carding gripping gap are transferred to the fibers of the carding roller;

[0055] (2) In the combing zone, starting from the point where the combing roller holds the gap, the combing roller needle separates the cotton sliver from the cotton roller into single fibers and sends them into the fiber conveying channel.

[0056] (3) In the fiber conveying channel, the single fiber flow is conveyed to the inner wall of the rotor under the negative pressure formed by the speed of the combing roller and the speed of the rotor;

[0057] (4) In the rotor, the single fiber captured in the rotor sliding surface is gradually accelerated to the rotor speed by the high speed of the rotor and gradually condensed in the coagulation tank along the sliding surface from the rotor position corresponding to the fiber conveying channel. When the fiber gradually stacked at the peeling point of the coagulation tank reaches the set yarn weight, it is twisted by the yarn drawing roller and drawn out through the yarn drawing twist resistance tube.

[0058] Therefore, by analyzing the speed distribution of the fiber sliver in the above four stages, the quantitative relationship between the weight of the fiber sliver and the speed of the yarn drawing roller is established, and the tail length of the yarn is calculated, that is, further performing the following step B.

[0059] Step B. Send a stop feeding command to the feed roller, controlling the feed roller to instantly reverse and stop. At the carding roller spacing point, the sliver conveyed by the feed roller will be broken. Under the operation of the guide roller and winding roller, the fibers remaining in the carding roller, fiber conveying channel, and rotor will be transformed into yarn under the action of the carding roller, fiber conveying channel, rotor, guide roller, and winding roller. At the same time, control the guide roller and winding roller to wind the yarn onto the winding mechanism, stopping the yarn tail in the guide twist-stop tube. This eliminates the need to find the yarn end from the bobbin in the traditional splicing process and controls the guide roller and winding roller to stop.

[0060] In practical applications, the fibers remaining in the combing roller, fiber conveying channel, and rotor cup in step B above include the sliver fibers transferred away by the combing roller when the cotton feed roller reverses instantaneously, the fibers remaining in the combing roller, the fibers remaining in the fiber conveying channel, the fibers remaining on the sliding surface in the rotor cup, and the fiber rings remaining in the coagulation groove in the rotor cup. The corresponding weights are calculated separately as follows.

[0061] Regarding the weight of the cotton sliver fibers transferred away by the combing rollers during the instantaneous reversal of the cotton feeding rollers. Obtain as follows:

[0062] Based on the length of the fiber held between the gripping point of the cotton feeding roller and the spacing point of the combing roller According to the following formula:

[0063] (1)

[0064] Obtain the weight of the held fiber. ,in, This indicates the fixed weight of the cotton swabs fed into the cotton roller.

[0065] After power failure, the feed roller decelerates to 50% of its set speed, then momentarily reverses to retract the sliver, causing it to break at the carding roller spacing point. Due to inertia, the carding roller continues to rotate, feeding the fibers gripped by the carding roller needles into the airflow channel, where they then enter the rotor under the influence of the airflow. Because the feed roller grips the sliver through a tight grip between the roller and the feed plate, while the carding roller grips the sliver through a carding grip between the carding needles and the feed plate, and because the main body length of the fiber is greater than the feed-carding grip spacing... Therefore, the breakage and separation of the cotton sliver is based on the spacing point of the combing rollers. One can imagine the weight of the fiber flow held within the feeding and combing sections. In addition to the weight of the fiber flow brought back by the reverse rotation of the cotton roller, the weight of the fiber flow transferred to the carding roller is... Define the fiber transfer rate from the feed roller to the carding roller when power is off. as follows:

[0066] (2)

[0067] Therefore, the fiber transfer rate when the cotton feeding roller reverses instantaneously downwards and transfers fibers to the combing roller is... According to the following formula:

[0068] (4)

[0069] Obtain weight .

[0070] In applications, fiber transfer rate The value has a significant impact on the length of the yarn tail, usually The value is related to factors such as the length and distribution of the main fiber, the fineness and distribution of the fiber, the sliver weight, the short fiber percentage, and the impurity content. Based on experiments and relevant experience, generally... The range of values ​​for is as follows:

[0071] (3)

[0072] ①If If the value is too large, a longer tail yarn length can be obtained. When it is used as the connector between the seed yarn and the fiber flow output from the rotor coagulation tank, the excessively long tail yarn will remain in the rotor, causing blockage of the coagulation tank channel and preventing normal connection.

[0073] ②If When the value is within a reasonable range, a reasonable tail yarn length can be obtained. When it is used as the connector between the seed yarn and the fiber flow output from the rotor cohesive tank, the tail yarn will stay at the peeling point inside the rotor and can form a normal connector with the fiber flow output from the rotor cohesive tank.

[0074] ③If If the value is too small, the tail yarn length will be too short. As a seed yarn, the tail yarn will not stay at the stripping point inside the rotor and will not be able to form a normal joint with the fiber flow output from the rotor cohesion tank.

[0075] Since the entire spinning process is continuous, after the equipment is powered off, the fiber weight from the carding roller gripping point (distance point) to the fiber feed channel inlet remains consistent with the fiber weight during the continuous spinning process; that is, the amount fed in equals the amount output. Therefore, the weight of the residual fiber in the carding roller... Obtain as follows:

[0076] According to the following formula:

[0077] (5)

[0078] Obtain the arc length of the combing roller corresponding time ,in, This indicates the arc length of the combing roller from the spacing point of the combing roller to the fiber conveying channel. Indicates the rotational speed of the combing rollers. This indicates the diameter of the combing roller.

[0079] Then follow the formula below:

[0080] (6)

[0081] Obtain weight ,in, This indicates the linear velocity of the yarn guide roller after power failure. This indicates the linear density of the yarn.

[0082] Since the entire spinning process is continuous, even after the equipment is powered off, the weight of the fiber flow in the fiber conveying channel remains consistent with the fiber weight during the continuous spinning process; that is, the amount fed in equals the amount output. Therefore, the weight of the residual fiber in the fiber conveying channel... Obtain as follows:

[0083] First, follow the formula below:

[0084] (7)

[0085] Obtain the linear velocity at the inlet of the fiber conveying channel ,in, This represents the correction factor used to convert the linear velocity of the combing roller into fiber transfer velocity. Indicates the rotational speed of the combing rollers. Indicates the diameter of the combing roller. This indicates the linear speed of the combing roller.

[0086] Simultaneously, use the following formula:

[0087] (8)

[0088] Obtain the linear velocity at the fiber conveyor outlet. ,in, This represents the correction factor used to convert the rotor linear velocity into fiber transfer velocity. Indicates the rotor speed. This represents the diameter of the corresponding circle on the sliding surface of the rotor.

[0089] Then follow the formula below:

[0090] (9)

[0091] Obtain the transfer time of the fiber flow within the fiber transport channel , This indicates the length of the fiber conveying channel.

[0092] Finally, use the following formula:

[0093] (10)

[0094] Obtain weight ,in, This indicates the linear velocity of the yarn guide roller after power failure. This indicates the linear density of the yarn.

[0095] Regarding the fiber weight within the rotor, the fibers that initially enter the rotor from the fiber feed channel are gradually accelerated to the rotor's rotational speed by the high-speed rotation of the rotor. During this acceleration, the fibers gradually condense along the sliding surface from the rotor position corresponding to the fiber feed channel outlet into the condensation tank. Therefore, the fiber volume within the rotor should be divided into two parts: the first part is the fiber weight from its initial entry into the rotor from the fiber feed channel outlet to the condensation tank position, and the second part is the fiber weight within the condensation tank.

[0096] Regarding the residual fibers on the sliding surface of the rotor, the process of fibers gradually entering the rotor's condensation tank from the fiber conveying channel outlet along the sliding surface is an accelerated process. Let the linear velocity of the condensation tank be... During the entire spinning process, continuous fibers are separated into single fibers after passing through the combing rollers and then uniformly reach the rotor sliding surface through the fiber conveying channel. They then form continuous fiber rings layer by layer in the coagulation tank, and the sliver is drawn out and twisted into yarn near the peeling point.

[0097] like Figure 6 As shown, a single fiber entering the rotor from the fiber feeding channel outlet can be considered as a particle M with a certain weight m. According to the literature, the centrifugal force on the fiber particle is much greater than its own weight. Moreover, the relative velocity between the fiber particle and the air is very small, so its own weight and air resistance can be ignored.

[0098] Therefore, regarding the weight of the residual fibers on the sliding surface in the rotor cup Obtain as follows:

[0099] First, the rotor radius corresponding to the point where the fiber is transferred to the rotor sliding surface is... angular velocity is And taking the fiber at that point as the fiber mass, the centrifugal force experienced by the fiber mass is obtained as follows: The component of the force of fiber particles along the wall of the rotor towards the condensation tank. The component of the force of the fiber particles perpendicular to the wall of the rotor. Acceleration of fiber particles along the sliding surface of the rotor The quality of fiber particles The coefficient of friction between the fiber and the rotor wall Inclination angle of the inner wall of the swivel cup The dynamic equations are constructed as follows:

[0100] (11).

[0101] Next, the time it takes for the fiber to slide from the fiber conveying channel outlet to the coagulation tank inside the rotor is defined as... Then, based on the length of the fiber sliding along the generatrix of the rotor's sliding surface during that time period, For the acceleration in equation (11) Taking the derivative, we obtain the following:

[0102] (12).

[0103] Then, based on the entire sliding process of the fiber transferring from the fiber conveying channel outlet to the rotor condenser, in equation (12)... and If the relationship is linearly increasing, then the following structure is constructed:

[0104] (13)

[0105] in, This represents the distance along the rotor's generatrix from the fiber conveying channel outlet to the location of the internal coagulation tank. This represents the diameter of the condensation tank.

[0106] Then, combining equations (11), (12), and (13), when the fiber slides from the fiber conveying channel outlet into the coagulation tank inside the rotor, that is... The time it takes for the fiber to slide from the fiber conveying channel outlet to the condensation tank can be determined using the characteristic root method. Then, according to the following formula (14):

[0107] (14)

[0108] The time it takes for the fiber to slide from the fiber conveying channel outlet to the coagulation tank inside the rotor is determined. .

[0109] Finally, use the following formula:

[0110] (15)

[0111] Obtain weight ,in, This indicates the linear speed of the yarn drawing roller.

[0112] Regarding the weight of the residual fiber rings in the coagulation tank of the rotor, when the rotor rotates at high speed, it can be assumed that the distribution of single fibers continuously input into the rotor coagulation tank through the fiber feeding channel and sliding surface within a very short time on the circumference of the rotor coagulation tank is equally probable. That is to say, the distribution length of the single fibers continuously input within the rotor coagulation tank within a very short time is the circumference of the rotor.

[0113] Taking the stripping point as the research object, the fiber at the stripping point moves within the rotor at a speed equal to its extraction speed relative to the rotor. Let... The point is any point within the rotating cup agglomeration tank, and the peeling point is set from... Starting from the point, it moves relative to the circumference of the rotating cup condenser for one revolution and then returns to the starting point. The number of times the stripping point passes the fiber feed channel outlet during this period (rotor rotation cycle) (the number of rotations of the rotor within one revolution of the stripping point within the rotor) is: This refers to the number of single fibers combined in the condensation tank.

[0114] Let the time it takes for the rotating cup to complete one revolution be... ,but:

[0115] (16)

[0116] Since the entire spinning process is continuous, the fiber feed and output remain balanced per unit time to ensure a stable yarn count. Therefore, based on the fiber merging effect in the condenser described above, and taking the stripping point as the research object, the linear density of the fiber rings within the rotor condenser can be considered as a linear distribution, such as... Figure 7 As shown, let the stripping point be at the beginning of one rotor cycle. At the end of the term That is, starting from the peeling point, the linear density of the fiber ring in the coagulation groove decreases linearly from high to low along the direction of movement from the peeling point, until it is zero at the position where the yarn is just pulled out from the peeling point by the yarn-drawing roller.

[0117] Regarding the weight of the residual fiber rings in the coagulation tank of the rotor cup According to the following formula:

[0118] (17)

[0119] Obtain weight ,in, Indicates the linear density of the yarn. This indicates the diameter of the condensation tank in the rotating cup.

[0120] Further analysis based on the weight of the residual fibers obtained above shows the length of yarn that the residual fibers are transformed into under the action of the combing roller, fiber conveying channel, rotor, yarn guide roller, and winding roller. Obtain as follows, then based on the length of the converted yarn. Control the operation of the yarn guide roller and the winding roller, stop the end of the yarn in the yarn guide twist tube, and finally control the yarn guide roller and the winding roller to stop rotating.

[0121] First, based on the weight of the cotton sliver fibers transferred away by the combing rollers when the cotton rollers momentarily reverse direction. The weight of residual fibers in the combing roller The weight of residual fibers in the fiber conveying channel The weight of residual fibers on the sliding surface in the rotor cup The weight of the residual fiber rings in the coagulation tank of the rotating cup According to the following formula:

[0122] (18)

[0123] Obtain the sum of weights Then follow the formula below:

[0124] (19)

[0125] Obtain the total weight of residual fibers The number of fiber rings corresponding to the weight of the rotating cup condenser. And the weight of the remaining residual fibers that are less than a complete fiber loop. .

[0126] The weight is Fiber flow forms in the rotor cup condenser The mass of the remaining fiber sliver after each fiber ring, so the remaining weight after power is cut off is Total length of spun yarn Including formation within the rotating cup condenser Length of each fiber ring and the remaining weight is The fibers gradually overlap in the coagulation tank according to the merging effect, forming a yarn tail that is from coarse to fine. ,but Length such as Figure 8 As shown.

[0127] According to the following formula:

[0128] (20)

[0129] For the remaining residual fibers, based on the rotor cup coalescence effect, fiber rings of varying thickness are gradually formed within the cohesion tank of the rotor cup, according to the following formula:

[0130] (twenty one)

[0131] Obtain the length corresponding to the yarn tail. ,in, This indicates the linear density of the yarn.

[0132] Finally, according to the following formula:

[0133] (twenty two)

[0134] Get length ,in, This indicates the diameter of the condensation tank in the rotating cup. This indicates the length of the yarn corresponding to all remaining fibers.

[0135] Regarding the calculation of the tail length and stopping position after power failure, the tail length after power failure... This refers to the linear speed of the yarn drawing roller after the power is cut off, starting from when the feed roller stops feeding cotton. Run for a specific time The length of the yarn that is drawn out is then stopped. Therefore, the key to calculating the tail length is to ensure that all the spinnable yarn length of the residual fiber in the spinning machine is drawn out, and that the end of the drawn-out tail yarn is kept in the yarn guide twist tube to prepare for automatic splicing.

[0136] It is known that the length of spinnable yarn remaining in the spinning machine after a power outage is... Using the peeling point inside the rotor as a reference, if the tail length is less than... If the tail yarn remains before the rotor's separation point, it will be pulled apart and carried away by the negative pressure airflow as the rotor rotates. Therefore, the tail yarn length should be greater than [a certain value]. Furthermore, it should not exceed the center position of the yarn guide tube. Since the tail end of the yarn is not held, if it exceeds the center position of the yarn guide tube, it may be affected by airflow disturbances in the workshop, causing the tail end to exit the yarn guide tube. Therefore, a safe tail length range should ensure that the tail end enters the yarn guide tube and does not exceed the center position. Let the distance from the bottom of the yarn guide tube to the rotor peeling point be... The length of the yarn guide twist-stop tube is Then, based on the length of the yarn transformed from the residual fibers... According to the following formula:

[0137] (twenty three)

[0138] The length to retain the tail, the length to retain the tail. This refers to the linear speed of the yarn drawing roller after the power is cut off, starting from when the feed roller stops feeding cotton. Run for a specific time Then stop drawing out the yarn length, and determine the control of the yarn draw-out tail length for the draw-out roller and winding roller. The yarn is wound onto the winding mechanism, and the yarn end is stopped inside the yarn guide tube. This indicates the length of the yarn feed roller corresponding to the tail length. The movement of the yarn, This indicates the linear velocity of the yarn guide roller after power failure. This indicates the distance from the bottom of the yarn guide twist-stop tube to the peeling point inside the rotor. This indicates the length of the yarn guide twist-stop tube.

[0139] Step C. Control the rotor and combing roller to start working, and control the winding roller to reverse. The unwound yarn is stored in the yarn storage tube as seed yarn under the action of negative pressure airflow. Then control the winding roller to stop and proceed to step D.

[0140] Step D. Control the start of the cotton feeding roller to feed the cotton sliver. The cotton sliver is separated into fibers by the combing roller and fiber conveying channel, and then conveyed to the coagulation tank in the rotor to coagulate and form a fiber stream. Then proceed to step E.

[0141] Step E. Control the yarn guide roller to reverse, release the seed yarn in the yarn storage tube and sink it into the coagulation tank in the rotor under the action of negative pressure airflow. It overlaps with the fiber flow in the coagulation tank, twists and wraps with each other to achieve splicing, and continues to spin the rotor to generate yarn. Then control the yarn guide roller and winding roller to rotate forward, continuously output the generated yarn and wind it into a cone.

[0142] Analysis of the overlap between seed yarn and fiber flow

[0143] Based on the implementation method of the automatic splicing function in rotor spinning, the key to the automatic splicing of the seed yarn and the fiber flow in the rotor is the overlap length of the seed yarn and the fiber flow, as well as the twisting time of the seed yarn and fiber flow. Taking the circumference of a rotor condensing tank as the research object and the stripping point of the rotor condensing tank as the reference, when the winding mechanism starts to guide the yarn, the overlap of the seed yarn and the fiber flow in the condensing tank can be divided into four types.

[0144] (1) As Figure 9 As shown, if the seed yarn released by the inverted yarn guide roller has not yet overlapped with the fiber flow condensed in the rotor, and the winding mechanism starts to guide the yarn, the splicing cannot be completed.

[0145] (2) Figure 10 As shown, the seed yarn released by the reverse rotation of the yarn guide roller overlaps with the fiber flow condensed in the rotor for a short length. The winding mechanism starts to guide the yarn. At this time, there will be a small detail at the joint. However, the twisting time is too short, resulting in insufficient joint strength, which affects the joint quality and has a low success rate.

[0146] (3) Figure 11As shown, the overlap length between the seed yarn released by the reverse rotation of the yarn guide roller and the fiber flow condensed in the rotor is the circumference of one rotor condensation groove. This length is ideal, and there will be a thick section at the joint. However, the twisting time may not meet the joint strength requirements, thus affecting the joint success rate.

[0147] (4) Figure 12 As shown, the seed yarn released by the reverse rotation of the lead roller overlaps with the fiber flow condensed within the rotor, with a maximum overlap length equal to the circumference of one rotor condensation groove. At this point, the fiber flow condensed within the rotor condensation groove forms a stable fiber ring, resulting in two thick nodes and one thin node at the joint. The strength at the joint is also reliable. Therefore, by using this joint model and adjusting the joint's morphology and structure within the allowable range of joint strength, joint quality meeting industrial requirements can be obtained.

[0148] In practical applications, the fourth seed yarn-fiber flow splicing model is selected as the method for achieving automatic splicing. The specific automatic splicing action is as follows:

[0149] First, the cotton roller is started to feed in the cotton sliver. The single fibers separated by the combing roller and airflow channel are sent into the rotor and gradually stacked in the condensing groove to form fiber rings. Then, the yarn guide roller reverses to release the seed yarn. The yarn tail left in the yarn guide twist stop is pushed past the rotor peeling point and into the rotor condensing groove under the action of negative pressure airflow. After it intersects and overlaps with the fiber rings in the condensing groove for a certain length, the yarn guide roller stops. As the rotor rotates, the seed yarn and the fiber rings wrap around each other and twist to form a twisted body. When the twisting time is reached, the winding mechanism starts to start the yarn guide.

[0150] Regarding the connector method triggered by restoring power in steps C to E above, in practical applications, in step... In the process, 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. The design makes the seed yarn overlap with the fiber flow in the coagulation tank, and the upper limit of the overlap length is the circumference of the rotor coagulation tank. In the overlapping state, the fiber flow condensed in the rotor coagulation tank forms a fiber ring.

[0151] Based on the above-designed overlapping structure between the seed yarn and the fiber flow, before steps C to E of the splicing method are executed, the various control parameters are adjusted in the following manner.

[0152] The yarn storage length after power is restored refers to the length of yarn retained in the yarn storage tube after the winding roller reverses and unwinds. After power is restored, first press the process negative pressure button. When the process and impurity removal negative pressure reach the set value, the yarn storage tube air supply door opens to maintain a certain negative pressure in the yarn storage tube. Then, the winding roller operates at the set speed. Reverse Time After stopping, the unwound yarn is retained in the yarn storage tube under the action of negative pressure airflow, completing the splicing preparation action; when the yarn guide roller reverse signal is received, the yarn guide roller starts at the set speed. The process involves reversing the flow of yarn, pulling out the yarn stored in the yarn storage tube as seed yarn, and releasing it to a specific position in the rotor coagulation tank. This ensures that the seed yarn and the fiber flow maintain sufficient overlap to guarantee the quality of the splice.

[0153] For the speed of the winding roller Reverse Time The length of the unwound yarn from the winding mechanism is The yarn is stored in a yarn storage tube as seed yarn under the action of negative pressure airflow, and the following model is constructed:

[0154] (twenty four)

[0155] in, This indicates the length of the seed yarn released from the yarn storage tube by controlling the reversal of the yarn guide roller in step E. , They represent Compared The preset lower and upper limits for upward movement, in specific applications, such as... , .

[0156] Based on the definition in step E, the speed of the yarn-drawing roller is controlled as follows: Reverse release delay The overlap length between the seed yarn in the yarn storage tube and the fiber flow in the coagulation tank is constructed. The length of the seed yarn released from the yarn storage tube by the reversal of the yarn drawing roller The relationship between them is as follows:

[0157] (25)

[0158] in, This indicates the distance from the bottom of the yarn guide twist-stop tube to the peeling point inside the rotor. Indicates the length of the yarn guide twist-stop tube and the release delay. This refers to the time from when the seed yarn is released by the starting rollers reversing until it stops.

[0159] 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.

[0160] Based on the linear density of the yarn Twist coefficient Then the critical twist And according to the rotor speed Yarn drawing speed The initial twist Further based on the overlap length Twisting delay The twist of the joint is Based on the theory of instantaneous twist of the inner yarn arm of the rotor, the following structure is constructed:

[0161] (26)

[0162] That is, twisting delay The control is based on the twist coefficient and critical twist For reference, by controlling the overlap length Achieved, twist delay The twisting time 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 is released from the drawing roller to when the winding mechanism starts drawing the yarn; different yarn types correspond to different applicable twist coefficients, which can be obtained by consulting the yarn types and twist coefficients in "Spinning Science".

[0163] The draw-out length of the yarn-drawing roller and the winding roller is controlled according to the method of stopping the machine and leaving the tail. The yarn, with a tail length, is wound onto the winding mechanism. The position of the yarn tail end within the yarn guide tube is determined, and this is combined with the overlap length. According to formula (25), the length of the seed yarn released from the yarn storage tube by reversing the yarn guide roller is determined. The control is further based on equation (24), which controls the length of the unwound yarn on the winding mechanism of the winding roller. Adjustments are made based on the overlap length. The control of twisting delay is achieved through equation (26). The control parameters in steps C to E of the joint method are determined by adjusting the parameters.

[0164] In practical applications, steps C to E of the joint method are executed according to the above control parameters to achieve the joint. Furthermore, during the execution of steps C to E of the joint method, a method for adjusting the joint morphology and structure based on the joint linear density and annual distribution is designed as follows: steps F to G.

[0165] Step F. First, perform a joint line density distribution analysis as follows.

[0166] The splice point is formed from the start of sliver feeding on the feed roller to the start of yarn drawing in the winding mechanism, and includes the fiber ring superimposed on the rotor's condensing groove and the release delay. It consists of three parts: the seed yarn entering the rotor coagulation tank, the newly fed fiber flow into the rotor coagulation tank when the yarn is first drawn in.

[0167] Regarding the weight of the fiber ring, it is determined based on the following yarn sinking delay, which includes the time from when the sliver is fed into the feeding rollers to when the winding mechanism starts to draw the yarn. Release delay and twisting delay Three time periods;

[0168] Deep yarn delay This refers to the time from when the cotton sliver is fed into the cotton roller until the lead roller begins to reverse and release the seed yarn;

[0169] Release delay This refers to the time from when the seed yarn is released by the infeed rollers reversing until it stops;

[0170] Twisting delay The twisting time refers to the time after the seed yarn and fiber ring overlap to form a twisted body, that is, the time from when the seed yarn is released from the starting roller to when the winding mechanism starts to start the yarn.

[0171] According to the speed at which the cotton roll is fed into the cotton roller Tampon weight The weight of the fiber ring is obtained as follows. ;

[0172] (27).

[0173] Regarding release delay The weight of the seed yarn entering the rotor coagulation tank is based on the total remaining fibers, including those of length [missing information]. The yarn length is The yarn tail, based on the weight of the remaining residual fibers corresponding to the yarn tail. Linear density of yarn Combined with overlap length As follows:

[0174] (28)

[0175] Get release delay The weight of the seed yarn entering the rotor coagulation tank .

[0176] 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:

[0177] (29)

[0178] Obtain the weight of the newly fed fiber stream in the rotor coagulation tank at the start of yarn feeding. .

[0179] Then follow the formula below:

[0180] (30)

[0181] The total weight of the fibers at the joint was obtained as follows .

[0182] Step G. Adjustment of connector morphology and structure.

[0183] The morphology and structure of the joint are determined by the weight distribution of the three fiber components within the condensation tank at the joint. Since the weight is... The fibers are distributed in the condensation tank in the form of fiber rings, so the weight of this part is evenly distributed around the circumference of the condensation tank; according to the fiber aggregation effect in the rotor condensation tank, the weight is The newly fed fiber stream is linearly distributed around the condenser, with a minimum linear density of zero and a maximum linear density equal to the set yarn linear density. Therefore, the splice morphology is determined by the overlap length of the seed yarn. Let the linear density of the fiber ring be... The maximum linear density of the newly fed fiber stream is the set yarn linear density. Considering the evenness of the yarn, excessive or abrupt changes in linear density at the joint should be avoided. Generally, a joint structure with an overlap length equal to the length of the tail yarn transition section should be selected, such as... Figure 13 As shown.

[0184] Based on weight The fibers are distributed in the form of fiber rings around the rotor agglomeration tank, and based on the fiber merging effect in the rotor agglomeration tank, the weight is... If the distribution of the newly fed fiber stream around the condenser is linear, then the linear density of the fiber ring is: The maximum linear density and bonding length of the newly fed fiber stream are The maximum linear density of the yarn tail, the maximum linear density of the seed yarn in the rotor coagulation tank, and the three values ​​are all set as the linear density of the yarn. Taking the peeling 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 respectively... , , The structure is as follows:

[0185] (31).

[0186] Then, based on the overlap length The adjustment is based on formula (26), which is achieved by adjusting the twist delay. Achieve joint twist Control, combined with sedimentation delay With release delay By controlling the maximum and minimum linear density of the joint, the morphology and structure of the joint can be regulated.

[0187] Applying the above design scheme to practice, Figure 14 Taking the TQFK86 rotor spinning machine as an example, the spinning process in Table 1 is used for normal spinning, and 20 sets of yarn tails are taken by manually stopping the machine.

[0188] Table 1

[0189]

[0190] The specific operation for manual shutdown is as follows: use the spinning process in Table 1 for normal spinning, and set the tail length after power failure. After the spinning process stabilizes, manually press the stop button. The guide roller will move 180mm and then the entire machine will stop completely. At this point, the guide roller will have drawn all the fiber slivers remaining in the spinning unit into yarn. Taking the guide roller grip point a as a reference, measure 180mm upwards from the guide roller grip point a and cut it. This will give you the length of the fiber sliver drawn out by the guide roller from the feed roller grip point g to the rotor peeling point p after the stop button is pressed. The length of the yarn within the distance from the rotor peeling point p to the yarn guide roller gripping point a. The length of the tail yarn after power failure, consisting of two parts The distance from the rotor peeling point p to the yarn-feeding roller gripping point a can be measured using the mechanical mechanism of the spinning machine, and the length of the yarn tail can also be determined. It can also be measured, then:

[0191] (32)

[0192] The mass and length of each of the 20 yarn groups were measured, and then the length of the formed yarn from the gripping point of the lead-in roller to the peeling point was subtracted from each yarn group. and its corresponding mass The length of the formed yarn from the gripping point of the yarn guide roller to the peeling point. If it is 187.343mm, then The average length and mass of the 20 sets of experimental data are shown in Table 2.

[0193] Table 2

[0194]

[0195] by Figure 14 Taking the TQFK86 rotor spinning machine as an example, the structural parameters of the TQFK86 rotor spinning machine are shown in Table 3. It is known that after a power outage, the speed of the yarn guide roller decreases to 50% of the normal spinning speed. The relevant structural parameters in Table 3 can be obtained through measurement. Combined with a mathematical model of the residual fiber weight of the rotor spinner after a power outage, the following can be calculated: , , , , The weight of the fibers, therefore the total weight of the fibers remaining after the equipment is powered off. It can be obtained.

[0196] Table 3

[0197]

[0198] (1) After a power outage, the fiber weight from the break point of the sliver to the holding point of the combing roller is calculated based on the shortest remaining yarn length, i.e., k is taken as 0.01. :

[0199] (33)

[0200] in: To determine the quantification of tampons, use 45g / 10m; The cotton-combing gripping distance is 18.274 mm, as shown in Table 2.

[0201] (2) The weight of the fiber from the gripping point of the combing roller to the inlet of the fiber conveying channel is: :

[0202] (34)

[0203] in: The arc length (mm) of the combing roller from the gripping point of the combing roller to the fiber conveying channel inlet is 102.638 mm, as shown in Table 2; the linear velocity of the yarn guide roller after power failure. (m / min) is 50% of the set value, which is 33.33 m / min; The yarn linear density (tex) is set to 37.6 tex; The speed of the combing roller (rpm) is set to 8000 rpm; The diameter of the combing roller (mm) is 65mm, as shown in Table 2.

[0204] (3) The weight of the fiber in the fiber transport channel is :

[0205] (35)

[0206] Wherein: the correction factor for converting the combing roller linear speed into fiber transfer speed. Correction factor for converting rotor linear velocity to fiber transfer velocity Take 1; The fiber feeding channel length, as shown in Table 2, is 22.811 mm; the yarn guide roller speed during tail retention... (m / min) is 50% of the set value, which is 33.33 m / min; The yarn linear density (tex) is set to 37.6 tex; Rotor speed (rpm), set to 50000 rpm; The speed of the combing roller (rpm) is set to 8000 rpm; The rotor radius corresponding to the fiber conveying channel outlet is 14.05 mm, as shown in Table 2. The radius of the combing roller is 32.5 mm, as shown in Table 2.

[0207] (4) The weight of the fiber within the sliding surface of the rotor is :

[0208] (36)

[0209] in: The diameter of the rotating cup condenser is 36 mm, as shown in Table 2. The distance from the fiber conveying channel outlet to the condenser along the rotor generatrix is ​​8.717 mm, as shown in Table 2; the yarn guide roller speed during tail retention. (m / min) is 50% of the set value, which is 33.33 m / min; The yarn linear density (tex) is set to 37.6 tex; The angle of inclination of the sliding surface of the rotor cup is 22°, as shown in Table 2. Let be the angular velocity of the rotating cup, which can be obtained from the rotational speed of the rotating cup. ; The coefficient of friction between the fiber and the cup wall is 0.35, as shown in Table 2.

[0210] (5) The weight of the fiber in the rotating cup agglomeration tank is :

[0211] (37)

[0212] in: The diameter of the rotating cup condenser is 36 mm, as shown in Table 1. The yarn linear density (tex) is taken as 37.6 tex.

[0213] (6) Total weight of residual fibers and length of spinnable yarn:

[0214] By analyzing the fiber transfer (velocity distribution) model for each of the above stages, a total of five fiber weights can be obtained, namely... , , , , After the power is cut off and the machine is stopped, the total weight of all fibers in the spinning machine is Then we have:

[0215] (38)

[0216] According to equation (19), the total weight of residual fibers after the equipment is powered off is known. and Then we can obtain , .

[0217] According to equation (22), the total length of the remaining fiber that can be spun into yarn after the power outage can be calculated as follows: :

[0218] (39)

[0219] (7) Length and position of the tail yarn:

[0220] The above calculations yielded... Compared with the total length of spinnable yarn remaining from the fibers after power failure obtained in Table 2, The average difference is 0.732 mm, which is negligible. Combining Figure 3(b) and the model of the yarn tail length and position after power failure, it can be seen that to accurately control the yarn tail to remain between the bottom and middle of the yarn guide tube after power failure, according to equation (23), the tail length... for:

[0221] (40)

[0222] in The distance from the bottom of the yarn guide twist-stop tube to the rotor peeling point is 49.776 mm, as shown in Table 2. The length of the yarn guide twist-stop tube is 50mm, as shown in Table 2. Therefore, under the spinning process described in Table 1, the tail length is... The minimum should be 211.901mm, and the maximum should be 236.901mm. It is known that the speed of the yarn feed roller during the tail-holding phase is 50% of the set value, i.e. According to equation (23), the minimum tail length is used. Substituting the values ​​into the calculation (i.e., the end of the yarn is currently at the bottom of the yarn guide tube), the yarn guide roller running time is then calculated. for:

[0223] (41)

[0224] (8) Seed yarn release length and yarn storage length:

[0225] according to Figure 13 From the seed yarn joint model, it can be seen that the overlap length is the length of the transition section of the seed yarn. Given that the tail yarn stops at the bottom of the yarn guide tube after power failure, according to equation (25), the seed yarn release length is... for:

[0226] (42)

[0227] in The distance from the bottom of the yarn guide twist-stop tube to the rotor peeling point can be found in Table 2. Given the seed yarn release length, set the reverse speed of the yarn guide roller. Then release delay for:

[0228] (43)

[0229] Given that the stored yarn length is generally 20mm-50mm longer than the seed yarn release length, and taking the stored yarn length to be 30mm longer than the seed yarn release length, according to formula (24), the stored yarn length is... for:

[0230] (44)

[0231] Given that the reversing speed of the winding roller is Then, the time is reversed by the coiled Lola. for:

[0232] (45)

[0233] (9) Twisting time:

[0234] During splicing, the rotor speed and yarn feeding speed are 50% of the set values, i.e. , The initial twist The maximum twist coefficient of the warp yarn, obtained from "Spinning Science", is: The yarn linear density is 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 (26), the overlap length is known to be... Then twisting time for:

[0235] (46)

[0236] (10) The shape and structure of the joint:

[0237] According to formula (27), combined with the yarn sinking delay Release delay Twisting delay and the diameter of the rotating cup condenser It is known that the speed at which the cotton roller feeds the swab during the joint is 50% of the set value, that is... Tampons are weighed as Then the linear density of the fiber ring for:

[0238] (47)

[0239] If the overlap length is equal to the length of the tail yarn transition section, then the maximum linear density of the seed yarn in the condensation tank is the set yarn linear density. The maximum linear density of the newly fed fiber stream is the set yarn linear density. According to equation (31), the overlap length is known to be... ,but Figure 13 In the joint structure, the linear densities corresponding to thick section 1, thin section, and thick section 2 are respectively (tex), (tex), (tex) is:

[0240] (48)

[0241] By controlling the sedimentation delay in formula (48) This allows for adjustment of the linear density of the two coarse sections and one fine section of the joint, thereby enabling control over the joint's shape. If we take... The maximum linear density of the joint minimum linear density .

[0242] This invention addresses the issue of yarn breakage during rotor spinning due to temporary shutdowns or power outages. It utilizes a UPS (Uninterruptible Power Supply) to provide backup power, controlling the operation of various components of the rotor spinning machine. By precisely calculating the remaining fiber length of the spinnable yarn after passing through the rotor, the invention guides the orderly shutdown of mechanisms such as the guide roller and winding roller, ensuring the broken yarn end stops within the twist stopper's guide tube, thus achieving automatic yarn tail retention during shutdown. Upon restarting or when power is restored, the doffing mechanism unwinds the broken yarn as seed yarn into the rotor's condensing groove. This yarn overlaps and twists with the fiber flow formed by the cotton sliver fed into the condensing groove via the combing roller and fiber conveying channel, completing the splicing action. Based on the yarn tail position of the automatic tail retention function, the invention further adjusts parameters such as linear density, twist, and strength of the seed yarn-fiber flow twist by precisely calculating the overlap length and twisting time, thereby improving the splicing success rate and achieving high-quality automatic splicing. It enables efficient and automated completion of automatic tail-keeping and automatic splicing functions during temporary stops or power outages in rotor spinning, thereby improving enterprise production efficiency.

[0243] 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. A method for automatic splicing of rotor spinning based on adjusting the tail length of the yarn, characterized in that, For rotor spinning machines with backup power, the tail position of the yarn is adjusted when the machine stops due to power failure. The following steps A to B are performed to implement the method of leaving the yarn tail during shutdown. Step A. The carding roller and the rotor stop naturally due to their own inertia. At the same time, based on the backup power supply and PLC control, the cotton feeding roller, yarn feeding roller and winding roller are decelerated to 30%~60% of the working speed. Then proceed to step B. Step B. The PLC sends a stop feeding command to the feed roller, controlling the feed roller to instantly reverse and stop. At the carding roller spacing point, the sliver conveyed by the feed roller is broken. Under the operation of the yarn guide roller and the winding roller, the fibers remaining in the carding roller, fiber conveying channel, and rotor are transformed into yarn by the action of the carding roller, fiber conveying channel, rotor, yarn guide roller, and winding roller. At the same time, the yarn guide roller and the winding roller are controlled to wind the yarn onto the winding mechanism, stopping the end of the yarn in the yarn guide twist-stopping tube, and controlling the yarn guide roller and the winding roller to stop. In step B of the shutdown and tail-retention method, the fibers remaining in the combing roller, fiber conveying channel, and rotor, including the sliver fibers transferred away by the combing roller when the feed roller momentarily reverses, the fibers remaining in the combing roller, the fibers remaining in the fiber conveying channel, the fibers remaining on the sliding surface in the rotor, and the fiber rings remaining in the cohesion groove in the rotor, are transformed into yarn of the corresponding length under the action of the combing roller, fiber conveying channel, rotor, yarn guide roller, and winding roller. Obtain as follows, then based on the length of the converted yarn. Execute the following formula: (23)； The length to retain the tail, the length to retain the tail. This refers to the linear speed of the yarn drawing roller after the power is cut off, starting from when the feed roller stops feeding cotton. Run for a specific time Then stop drawing out the yarn length, and determine the control of the yarn draw-out tail length for the draw-out roller and winding roller. The yarn is wound onto the winding mechanism, and the yarn end is stopped inside the yarn guide twist-stopping tube. Finally, the yarn guide roller and winding roller are stopped. Indicates the tail length corresponding to the yarn feeding roller. Yarn running time, This indicates the linear velocity of the yarn guide roller after power failure. This indicates the distance from the bottom of the yarn guide twist-stop tube to the peeling point inside the rotor. Indicates the length of the yarn guide twist-stop tube; First, based on the weight of the cotton sliver fibers transferred away by the combing rollers when the cotton rollers momentarily reverse direction. The weight of residual fibers in the combing roller The weight of residual fibers in the fiber conveying channel The weight of residual fibers on the sliding surface in the rotor cup The weight of the residual fiber rings in the coagulation tank of the rotating cup The sum of their weights ,according to Obtain the total weight of all residual fibers. The number of fiber rings corresponding to the weight of the rotating cup condenser. And the weight of the remaining residual fibers that are less than a complete fiber loop. ; Then, for the remaining residual fibers, based on the rotor cup coalescence effect, fiber rings of varying thickness are gradually formed within the cohesion tank of the rotor cup. Obtain the length corresponding to the yarn tail. ,in, Indicates the linear density of the yarn; Finally, based on , obtain length ,in, This indicates the diameter of the condensation tank in the rotating cup. This indicates the length of the yarn corresponding to all remaining fibers; Based on the control of the process of overlapping the new fiber ring formed in the rotor coagulation tank with the tail yarn after the spinning is restarted by powering on, the splicing method is as follows: steps C to E. Step C. Control the rotor and combing roller to start working, and control the winding roller to reverse. The unwound yarn is stored in the yarn storage tube as seed yarn under the action of negative pressure airflow. Then control the winding roller to stop and proceed to step D. Step D. Control the start of the cotton feeding roller to feed cotton sliver. The cotton sliver is separated into fibers by the combing roller and fiber conveying channel, and then conveyed to the coagulation tank in the rotor to coagulate and form a fiber stream, and then proceed to step E; Step E. Control the yarn guide roller to reverse, release the seed yarn in the yarn storage tube and sink it into the coagulation tank in the rotor under the action of negative pressure airflow. It overlaps with the fiber flow in the coagulation tank, twists and wraps with each other to achieve splicing, and continues to spin the rotor to generate yarn. Then control the yarn guide roller and winding roller to rotate forward, continuously output the generated yarn and wind it into a cone.

2. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length as described in claim 1, characterized in that, Regarding the weight of the cotton sliver fibers transferred away by the combing rollers during the instantaneous reversal of the cotton feeding rollers. Obtain as follows: Based on the length of the fiber held between the gripping point of the cotton feeding roller and the spacing point of the combing roller ,according to To obtain the weight of the held fiber. ,in, This indicates the fixed weight of the cotton swabs fed into the cotton roller; Then, the fiber transfer rate is increased when the cotton roller is instantly reversed and transferred to the combing roller. ,according to Obtain weight .

3. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 1, characterized in that, The weight of residual fibers in the combing roller Obtain as follows: according to Obtain the arc length of the combing roller. corresponding time ,in, This indicates the arc length of the combing roller from the spacing point of the combing roller to the fiber conveying channel. Indicates the rotational speed of the combing rollers. Indicates the diameter of the combing roller; Then press Obtain weight ,in, This indicates the linear velocity of the yarn guide roller after power failure. This indicates the linear density of the yarn.

4. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 1, characterized in that, The weight of residual fibers in the fiber transport channel Obtain as follows: First press Obtain the linear velocity at the inlet of the fiber conveying channel. ,in, This represents the correction factor used to convert the linear velocity of the combing roller into fiber transfer velocity. Indicates the rotational speed of the combing rollers. Indicates the diameter of the combing roller. Indicates the linear speed of the combing rollers; Press at the same time Obtain the linear velocity at the outlet of the fiber conveying channel. ,in, This represents the correction factor used to convert the rotor linear velocity into fiber transfer velocity. Indicates the rotor speed. This represents the diameter of the corresponding circle on the sliding surface of the rotor. Then press The transfer time of the fiber flow within the fiber transport channel is obtained. , Indicates the length of the fiber conveying channel; Finally press Obtain weight ,in, This indicates the linear velocity of the yarn guide roller after power failure. This indicates the linear density of the yarn.

5. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 1, characterized in that, The weight of residual fibers on the sliding surface in the rotor. Obtain as follows: First, the rotor radius corresponding to the point where the fiber is transferred to the rotor sliding surface is... angular velocity is And taking the fiber at that point as the fiber mass, the centrifugal force experienced by the fiber mass is obtained as follows: The component of the force of fiber particles along the wall of the rotating cup towards the condensation tank. The component of the force of the fiber particles perpendicular to the wall of the rotor. Acceleration of fiber particles along the sliding surface of the rotor The quality of fiber particles The coefficient of friction between the fiber and the rotor wall Inclination angle of the inner wall of the swivel cup The dynamic equations are constructed as follows: (11)； Next, the time it takes for the fiber to slide from the fiber conveying channel outlet to the coagulation tank inside the rotor is defined as... Then, based on the length of the fiber sliding along the generatrix of the rotor's sliding surface during that period, For the acceleration in equation (11) Taking the derivative, we obtain the following: (12)； Then, based on the entire sliding process of the fiber transferring from the fiber conveying channel outlet to the rotor condenser, in equation (12)... and If the relationship is linearly increasing, then the following structure is constructed: (13)； in, This represents the distance along the rotor's generatrix from the fiber conveying channel outlet to the location of the internal coagulation tank. This is expressed as the diameter of the condensation tank; Then, combining equations (11), (12), and (13), when the fiber slides from the fiber conveying channel outlet into the coagulation tank inside the rotor, that is... Then, by using the characteristic root method, according to the following formula (14): (14)； The time it takes for the fiber to slide from the fiber conveying channel outlet to the coagulation tank inside the rotor is determined. ; Finally press Obtain weight ,in, This indicates the linear speed of the yarn guide roller after power failure.

6. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 1, characterized in that, The weight of the residual fiber rings in the coagulation tank of the rotating cup ,according to Obtain weight ,in, Indicates the linear density of the yarn. This indicates the diameter of the condensation tank in the rotating cup.

7. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 1, characterized in that: In step E of the splicing method, 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.

8. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 7, characterized in that: Before steps C to E of the joint method are executed, the various control parameters are adjusted as follows: For the speed of the winding roller Reverse Time The length of the unwound yarn from the winding mechanism is The yarn is stored in a yarn storage tube as seed yarn under the action of negative pressure airflow, and the following model is constructed: (24)； in, This indicates the length of the seed yarn released from the yarn storage tube by controlling the reversal of the yarn guide roller in step E. , They represent Compared The preset lower limit length and preset upper limit length for upward movement; Based on the definition in step E, the speed of the yarn-drawing roller is controlled as follows: Reverse release delay The overlap length between the seed yarn in the yarn storage tube and the fiber flow in the coagulation tank is constructed. The length of the seed yarn released from the yarn storage tube by the reversal of the yarn drawing roller The relationship between them is as follows: (25)； in, This indicates the distance from the bottom of the yarn guide twist-stop tube to the peeling point inside the rotor. Indicates the length of the yarn guide twist-stop tube and the release delay. This refers to the time from when the seed yarn is released by the infeed rollers reversing until it stops; Based on the linear density of the yarn Twist coefficient Then the critical twist And according to the rotor speed Linear velocity of the yarn guide roller after power failure The initial twist Further based on the overlap length Twisting delay The twist of the joint is Based on the theory of instantaneous twist of the inner yarn arm of the rotor, the following structure is constructed: (26)； That is, twisting delay The control is based on the twist coefficient and critical twist For reference, by controlling the overlap length Achieved; twisting delay The twisting time 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 is released from the starting roller to when the winding mechanism starts to start the yarn feeding. The draw-out length of the yarn-drawing roller and the winding roller is controlled according to the method of stopping the machine and leaving the tail. The yarn, with a tail length, is wound onto the winding mechanism. The position of the yarn tail end within the yarn guide tube is determined, and this is combined with the overlap length. According to formula (25), the length of the seed yarn released from the yarn storage tube by reversing the yarn guide roller is determined. The control is further based on equation (24), which controls the length of the unwound yarn on the winding mechanism of the winding roller. Adjustments are made based on the overlap length. The twisting delay is controlled by equation (26). The control parameters in steps C to E of the joint method are determined by adjusting the parameters.

9. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 8, characterized in that, The execution of steps C to E of the joint method also includes a method for adjusting the joint morphology and structure based on the joint linear density distribution, as shown in steps F to G below: Step F. First, perform the joint line density distribution analysis as follows: The splice point is formed from the start of sliver feeding on the feed roller to the start of yarn drawing in the winding mechanism, and includes the fiber ring superimposed on the rotor's condensing groove and the release delay. It consists of three parts: the seed yarn that enters the rotor coagulation tank, the fiber flow that is newly fed into the rotor coagulation tank when the yarn is first drawn; Regarding the weight of the fiber ring, it is determined based on the following yarn sinking delay, which includes the time from when the sliver is fed into the feeding rollers to when the winding mechanism starts to draw the yarn. Release delay and twisting delay Three time periods; Deep yarn delay This refers to the time from when the cotton sliver is fed into the cotton roller until the lead roller begins to reverse and release the seed yarn; According to the speed at which the cotton roll is fed into the cotton roller Tampon weight The weight of the fiber ring is obtained as follows. ; (27)； Regarding release delay The weight of the seed yarn entering the rotor coagulation tank is based on the total remaining fibers, including those of length [missing information]. The yarn length is The yarn tail, based on the weight of the remaining residual fibers corresponding to the yarn tail. Linear density of yarn Combined with overlap length As follows: (28)； Get release delay The weight of the seed yarn entering the rotor coagulation tank ; 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: (29)； Obtain the weight of the newly fed fiber stream in the rotor coagulation tank at the start of yarn feeding. ; Then follow the formula below: (30)； The total weight of the fibers at the joint was obtained as follows ; Step G. Adjustment of joint morphology and structure: Based on weight The fibers are distributed in the form of fiber rings around the rotor agglomeration tank, and based on the fiber merging effect in the rotor agglomeration tank, the weight is... If the distribution of the newly fed fiber stream around the condenser is linear, then the linear density of the fiber ring is: The maximum linear density and bonding length of the newly fed fiber stream are The maximum linear density of the yarn tail, the maximum linear density of the seed yarn in the rotor coagulation tank, and the three values ​​are all set as the linear density of the yarn. Taking the peeling 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 respectively... , , The structure is as follows: (31)； Then, based on the overlap length The adjustment is based on formula (26), which is achieved by adjusting the twist delay. Achieve joint twist Control, combined with sedimentation delay With release delay By controlling the maximum and minimum linear density of the joint, the morphology and structure of the joint can be regulated.

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