Description:TECHNICAL FIELD
[0001] The present invention relates to a yarn winding apparatus that winds yarn to form a package.

BACKGROUND ART
[0002] There is known a yarn winding apparatus that winds yarn fed from a yarn feeding unit around a take-up pipe to form a package. In the yarn winding apparatus, it is necessary that a yarn winding amount when yarn winding on the package is finished is not varied from a predetermined winding amount. For this reason, deceleration of the package is started at timing when the yarn winding amount of the package becomes a winding amount a little less than the above predetermined winding amount (see, for example, JPH05-286646A).

SUMMARY OF INVENTION
TECHNICAL PROBLEM
[0003] In the yarn winding apparatus, depending on winding conditions, a yarn speed when forming the package may be changed. In this case, if the timing of decelerating the package is determined considering only the yarn winding amount of the package as described above, a variation will occur in the yarn winding amount when yarn winding on the package is finished. Specifically, the yarn winding amount of the package when winding is finished is different depending on a yarn speed just before decelerating the package.
[0004] It is an object of the present invention to keep a yarn winding amount of the package when winding is finished constant, even in a case where the yarn speed is changed when winding yarn on the package.

TECHNICAL SOLUTION
[0005] Hereinafter, a plurality of embodiments are described as means for solving the problem. These embodiments can be arbitrarily combined as necessary.
A yarn winding apparatus according to one aspect of the present invention includes a yarn feeding unit, a winding unit, and a control unit. The yarn feeding unit is configured to feed yarn. The winding unit is configured to wind the yarn to form a package. The control unit is configured to control the winding unit. The control unit performs deceleration stop control of the winding unit. The deceleration stop control is a control for decelerating a yarn speed as a yarn running speed from a package forming yarn speed, to be zero when the length of the yarn wound on the package becomes a preset package winding end length. In this case, start timing of the deceleration stop control is determined based on the package winding end length, the package forming yarn speed, and the length of the yarn wound on the package.
[0006] In the yarn winding apparatus that finishes yarn winding on the package by the above deceleration stop control, the start timing of the deceleration stop control is determined considering not only the length of the yarn wound on the package but also the package forming yarn speed, i.e., the yarn speed just before the deceleration stop control is started, and hence it is possible to keep a yarn winding amount of the package when the winding is finished substantially constant, as the package winding end length, even if the package forming yarn speed is different.
[0007] In the above yarn winding apparatus, a deceleration rate of the yarn in the deceleration stop control may be set in advance. In this way, a time period necessary for decreasing the yarn speed from the speed just before starting the deceleration stop control to zero can be known, and hence the start timing of the deceleration stop control can be accurately determined.
[0008] In the above yarn winding apparatus, the deceleration rate of the yarn in the deceleration stop control may be changeable. In this way, package formation conditions can be set more flexibly.
[0009] In the above yarn winding apparatus, the winding unit may include a rotary drive unit that is configured to rotate the package. In this case, the control unit may measure the length of the yarn wound on the package based on a drive amount of the rotary drive unit. In this way, there is no need to dispose a sensor that can directly measure the length of the wound yarn.
[0010] In the above yarn winding apparatus, the winding unit may further include a braking device that is configured to decelerate rotation speed of the package. In this case, the control unit may perform the deceleration stop control by using both deceleration of the package by the braking device and deceleration of the rotary drive unit. In this way, rotation of the package can be stopped in a short time while suppressing slippage between the package and the rotary drive unit.
[0011] In addition, in the case of using both the deceleration of the package by the braking device and deceleration of the rotary drive unit, when the deceleration stop control is finished, the package is contacted with the rotary drive unit, and the yarn is connected. In other words, when the deceleration stop control is finished, lifting up for separating the package from the rotary drive unit is not performed, but by determining the start timing of the deceleration stop control as described above, the yarn winding amount of the package when winding is finished can be substantially constant as the package winding end length, without the lifting up.
[0012] The above yarn winding apparatus may further include an accumulating roller. The accumulating roller is disposed between the yarn feeding unit and the winding unit in a yarn running direction, and is configured to wind the yarn to temporarily accumulate the same. In this case, the control unit may measure the length of the yarn wound on the package, based on the number of rotations of the accumulating roller. In this way, regardless of a shape of the package, the length of the yarn wound on the package can be accurately measured.
[0013] The above yarn winding apparatus may further include a yarn amount detection sensor. The yarn amount detection sensor is configured to detect that a yarn retention amount on the accumulating roller has become a predetermined retention amount. In this case, the control unit may measure the length of the yarn wound on the package, based on the number of rotations of the accumulating roller after the yarn amount detection sensor detects that the yarn retention amount on the accumulating roller has become the predetermined retention amount. When starting (restarting) to form the package, the yarn retention amount on the accumulating roller is uncertain (varied), and hence the length of the yarn measured based on the number of rotations of the accumulating roller from the start of formation is not accurate. Therefore, as described above, by measuring the length of the yarn based on the number of rotations of the accumulating roller after the yarn retention amount on the accumulating roller has become the predetermined retention amount, it is possible to measure the length of the yarn more accurately.
[0014] In the above yarn winding apparatus, when starting forming the package, the control unit may set a yarn winding speed on the package to be lower than a yarn accumulating speed on the accumulating roller. In this way, it is possible to shorten the time period after starting forming the package until the predetermined retention amount of yarn is accumulated on the accumulating roller, and hence it is possible to advance the start timing of measuring the length of the yarn based on the number of rotations of the accumulating roller.
[0015] In the above yarn winding apparatus, the control unit may calculate a deceleration stop yarn length, which is length of the yarn wound on the package from start to end of the deceleration stop control, based on the package forming yarn speed, and may determine the time when the length of the yarn wound on the package becomes a deceleration start yarn length, which is obtained by subtracting the deceleration stop yarn length from the package winding end length, as the start timing of the deceleration stop control. In this way, the start timing of the deceleration stop control can be accurately determined, based on the package winding end length, the package forming yarn speed, and the length of the yarn wound on the package.
[0016] In the above yarn winding apparatus, the deceleration stop yarn length may change linearly with respect to the package forming yarn speed. In this way, the deceleration stop yarn length can be easily calculated.

ADVANTAGEOUS EFFECTS
[0017] It is possible to keep a yarn winding amount of the package when winding is finished, as the package winding end length, substantially constant even if the package forming yarn speed is different.

BRIEF DESCRIPTION OF DRAWINGS
[0018] Fig. 1 is a diagram illustrating a structure of an automatic winder.
Fig. 2 is a diagram illustrating a structure of a winder unit.
Fig. 3 is a diagram illustrating a structure of a package forming unit.
Fig. 4 is an enlarged diagram of an accumulating roller.
Fig. 5 is a diagram illustrating a control structure of a control device.
Fig. 6 is a flowchart illustrating a package forming operation using the winder unit.
Fig. 7 is a diagram illustrating an example of temporal changes of yarn winding lengths for different yarn speeds.
Fig. 8 is a diagram illustrating an example of a temporal change of the yarn speed when package formation is finished by multiple steps of deceleration.

DESCRIPTION OF EMBODIMENTS
[0019] 1. First Embodiment
(1) Automatic Winder
Hereinafter, a first embodiment is described in detail. Note that in description of the drawings, the same or corresponding element is denoted by the same numeral or symbol, and overlapping description is omitted. The terms of "upstream" and "downstream" respectively mean upstream and downstream in a yarn running direction.
[0020] With reference to Fig. 1, an automatic winder 1 is described. Fig. 1 is a diagram illustrating a structure of the automatic winder 1. The automatic winder 1 includes a plurality of winder units 2 arranged side by side, a machine stand control device 3, a yarn feeding bobbin supply device 4, and a doffing device 5. In addition, the automatic winder 1 is provided with a blower box.
[0021] The winder unit 2 winds yarn Y on a winding bobbin 22 to form a package 30. The winder unit 2 unwinds the yarn Y from a yarn feeding bobbin 21, temporarily accumulates the unwound yarn Y in a yarn accumulating device 40, and then pulls out the yarn Y accumulated in the yarn accumulating device 40, to wind the same on the winding bobbin 22, thereby forming the package 30.
[0022] The machine stand control device 3 is configured to communicate with each of the winder units 2. An operator of the automatic winder 1 can centrally manage the plurality of winder units 2 by appropriately operating the machine stand control device 3. The machine stand control device 3 controls operations of the yarn feeding bobbin supply device 4 and the doffing device 5.
[0023] The yarn feeding bobbin supply device 4 sets the yarn feeding bobbin 21 on a transport tray 26 one by one. The yarn feeding bobbin supply device 4 supplies the yarn feeding bobbin 21 set on the transport tray 26 to each of the plurality of winder units 2.
[0024] When the package 30 becomes a fully wound state (a state where a defined amount of the yarn Y is wound) in the winder unit 2, the doffing device 5 travels to the position of the winder unit 2, and detaches the fully wound package 30. The doffing device 5 sets another winding bobbin 22 without the yarn Y to the winder unit 2 from which the package 30 has been detached.
[0025] (2) Winder Unit
(2-1) Schematic Structure of Winder Unit
Hereinafter, a structure of the winder unit 2 is described. First, with reference to Fig. 2, a schematic structure of the winder unit 2 is described. Fig. 2 is a diagram illustrating a structure of the winder unit 2. The winder unit 2 includes a yarn feeding unit 6, the yarn accumulating device 40, a yarn guide unit 7, a package forming unit 8, and a control device 25.
[0026] The yarn feeding unit 6 is configured to support the yarn feeding bobbin 21 set on the transport tray 26 at a predetermined position, to unwind the yarn Y from the yarn feeding bobbin 21. When the yarn Y is fully unwound from the yarn feeding bobbin 21, the yarn feeding unit 6 discharges a core tube of the yarn feeding bobbin 21 without the yarn Y, and receives a new yarn feeding bobbin 21 supplied from the yarn feeding bobbin supply device 4.
[0027] The yarn accumulating device 40 is disposed in a yarn running path between the yarn feeding unit 6 and the package forming unit 8. The yarn accumulating device 40 is disposed at a position on an upstream side of a wax applying device 70 in a running direction of the yarn Y. The yarn accumulating device 40 winds the yarn Y unwound in the yarn feeding unit 6 to temporarily accumulate the same. The yarn accumulating device 40 supplies the accumulated yarn Y to the package forming unit 8.
[0028] The yarn guide unit 7 is disposed between the yarn feeding unit 6 and the yarn accumulating device 40, and guides the yarn Y fed from the yarn feeding unit 6 between the yarn feeding unit 6 and the yarn accumulating device 40. In the yarn guide unit 7, when the yarn Y is disconnected between the yarn feeding unit 6 and the yarn accumulating device 40, a termination part of the yarn Y on the yarn feeding unit 6 side and a termination part of the yarn Y on the yarn accumulating device 40 side are spliced.
[0029] The package forming unit 8 winds the yarn Y fed from the yarn accumulating device 40 on the winding bobbin 22 to form the package 30.
[0030] The control device 25 is a computer system having hardware including an information processing circuit such as a CPU and the like, a storage device (such as a ROM and a RAM), various interfaces, and the like. The storage device stores software such as a control program. The control device 25 controls each structural element of the winder unit 2 by cooperation between hardware and software. The control device 25 is configured to be communicable with the machine stand control device 3. In this way, it is possible to centrally manage the operations of the plurality of winder units 2 of the automatic winder 1 by the machine stand control device 3.
[0031] The winder unit 2 may include the wax applying device 70. The wax applying device 70 is disposed between the yarn accumulating device 40 and the package forming unit 8. The wax applying device 70 applies wax onto the yarn Y running from the yarn accumulating device 40 to the package forming unit 8.
[0032] (2-2) Package forming unit
Hereinafter, with reference to Fig. 3, the package forming unit 8 is described. Fig. 3 is a diagram illustrating a structure of the package forming unit 8. The package forming unit 8 includes a cradle 23 and a traverse drum 24. The cradle 23 supports the winding bobbin 22 (or the package 30) in a rotatable manner. The cradle 23 is configured to allow the outer periphery of the supported package 30 to contact or separate from the outer periphery of the traverse drum 24.
[0033] The cradle 23 includes a pair of cradle arms 23a and 23b. The cradle arms 23a and 23b are supported in a pivotable manner about an axis A1, to pivot in a direction approaching or separating from the traverse drum 24.
[0034] Distal ends of the cradle arms 23a and 23b are provided with bobbin holders 23c and 23d for holding the winding bobbin 22 in a rotatable manner. The bobbin holders 23c and 23d respectively have holder main bodies 23e and 23f engaging with ends of the winding bobbin 22 in the rotational axial direction. The holder main bodies 23e and 23f engage with the ends of the winding bobbin 22, to rotate together with the winding bobbin 22 integrally.
[0035] The bobbin holder 23c includes a braking device 60 inside. The braking device 60 has a brake shoe that approaches or separates from the holder main body 23e. The brake shoe can move by air pressure supplied from an air pressure varying unit 60a. Specifically, when the air pressure varying unit 60a increases air pressure, the brake shoe contacts the holder main body 23e to act as a brake on rotation of the winding bobbin 22 (the package 30). Using the air pressure by the air pressure varying unit 60a, the deceleration rate in the rotation speed of the winding bobbin 22 (the package 30) can be adjusted.
[0036] In addition, a package rotation number sensor 61 is disposed near the bobbin holder 23d, and detects the number of rotations of the package 30 to output the same to the control device 25.
[0037] The traverse drum 24 is driven to rotate by a drum drive motor 62. When the traverse drum 24 rotates while contacting the package 30, the winding bobbin 22 and the package 30 are driven to rotate. The drum drive motor 62 is a position controllable motor such as a DC brushless motor, a stepping motor, or a servo motor, for example.
[0038] A drum rotation number sensor 63 is disposed in a vicinity of the traverse drum 24. The drum rotation number sensor 63 detects the number of rotations of the traverse drum 24 and outputs the same to the control device 25. Note that the number of rotations of the traverse drum 24 may be measured by a sensor (such as an encoder) that measures the number of rotations of the drum drive motor 62.
[0039] A traversing groove 24a is formed on the outer periphery of the traverse drum 24. The traverse drum 24 rotates while allowing the yarn Y to pass through the traversing groove 24a, to traverse the yarn Y by a predetermined width. With the structure described above, the yarn Y can be traversed and wound around the winding bobbin 22 to form the package 30 having a predetermined shape.
[0040] (2-3) Yarn Accumulating Device
With reference to Figs. 2 and 4, a detailed structure of the yarn accumulating device 40 is described. Fig. 4 is an enlarged diagram of an accumulating roller 41. The yarn accumulating device 40 includes the accumulating roller 41 on which the yarn Y can be wound, and a drive motor 45 that drive the accumulating roller 41 to rotate.
[0041] The accumulating roller 41 has a drum shape, and allows the yarn Y to be wound on an outer periphery 41d of the accumulating roller 41 in an accumulating region A, to temporarily accumulate the yarn Y. The accumulating roller 41 is supported by a machine stand (frame) of the automatic winder 1, in a rotatable manner about a rotation axis C1 slightly tilted from a horizontal direction. As illustrated in Figs. 2 and 4, both end sides of the accumulating roller 41 in the axial direction are respectively provided with tapered portions 41a and 41b whose diameters increase toward the ends. The portion between the two tapered portions 41a and 41b is a cylindrical portion 41c having a constant diameter, and the outer periphery 41d of the cylindrical portion 41c is the accumulating region A on which the yarn Y is wound. The outer periphery 41d of the cylindrical portion 41c is mirror-finished. The two tapered portions 41a and 41b on both end sides prevents the yarn Y wound on the cylindrical portion 41c from falling off.
[0042] A ring member 42 is wound around the outer periphery 41d of the cylindrical portion 41c of the accumulating roller 41. The ring member 42 is made of rubber, for example, and is formed in a ring shape. The ring member 42 is attached to a boundary between the cylindrical portion 41c and the tapered portion 41b on the distal end side. The ring member 42 is a tension ring, which surrounds the yarn Y pulled out from the accumulating roller 41 by the package forming unit 8, and contacts the yarn Y to give a resistance. The ring member 42 is attached onto the cylindrical portion 41c with its elastic force inward in the radial direction. The ring member 42 gives a resistance by its elastic force to the yarn Y pulled out from the accumulating roller 41. The ring member 42 supplies the yarn Y pulled out from the accumulating roller 41 with an appropriate tension, and unwinding of the yarn Y from the accumulating roller 41 is stabilized.
[0043] On the outer periphery 41d of the accumulating roller 41, a first recess (recess) 43a is disposed in a region that covers the attachment position of the ring member 42 in the direction along the rotation axis C1. In other words, viewing from outside of the accumulating roller 41 in the radial direction, the first recess 43a is disposed to pass the attachment position of the ring member 42 to cross the attachment position, and the first recess 43a partially overlaps the attachment position. Here, the first recess 43a constitutes a groove extending in the direction along the rotation axis C1 from one end to the other end of the accumulating roller 41. The first recess 43a has the same cross-sectional shape in its longitudinal direction, for example, and is formed in a substantially rectangular cross-sectional shape. A second recess (recess) 43b is further formed on the outer periphery 41d of the accumulating roller 41. The second recess (recess) 43b is a recess (a so-called downgage) that is formed to prevent formation of a depression (a so-called sink mark), when forming a boss for embedding a sensor magnet or a reinforcing rib on an inner periphery 41g of the cylindrical portion 41c.
[0044] The drive motor 45 rotates the accumulating roller 41 in the direction winding the yarn Y fed from the yarn feeding unit 6. In addition, the drive motor 45 can also rotate the accumulating roller 41 in the direction opposite to the winding direction. The drive motor 45 is a position controllable motor such as a DC brushless motor, a stepping motor, or a servo motor, for example.
[0045] The yarn accumulating device 40 includes an accumulating roller rotation number sensor 46 (Fig. 5). The accumulating roller rotation number sensor 46 measures the number of rotations of the accumulating roller 41. This accumulating roller rotation number sensor 46 is connected to an output rotation shaft of the drive motor 45, for example, and measures the number of rotations of the accumulating roller 41, based on the number of rotations of the output rotation shaft. The accumulating roller rotation number sensor 46 is an encoder, for example.
[0046] The yarn Y wound around the accumulating roller 41 is pulled out from the tapered portion 41b on the other end side of the accumulating roller 41 (the upstream side of the accumulating roller 41) and is sent to the downstream side (the package forming unit 8 side). At the tapered portion 41b, the yarn Y on the accumulating roller 41 is pulled out to the downstream side via a pull-out guide 37 positioned on the extension line of the rotation axis C1 of the accumulating roller 41. The yarn Y wound around the accumulating roller 41 is unwound through a gap between the accumulating roller 41 and the ring member 42, and thus the unwound yarn Y is supplied with an appropriate tension.
[0047] A yarn amount detection sensor 50 is disposed in a vicinity of the outer periphery 41d of the accumulating roller 41 of the cylindrical portion 41c. The yarn amount detection sensor 50 detects that the retention amount of the yarn Y on the accumulating roller 41 has become the predetermined retention amount. Note that the yarn amount detection sensor 50 may have a detection range from an upper limit amount to a lower limit amount of the retention amount. For instance, the yarn amount detection sensor 50 can be constituted of a light source 53 that emits light to the accumulating roller 41, and a sensor 55 that is disposed not to receive light reflected by the outer periphery 41d but to receive light reflected by the yarn Y accumulated on the accumulating roller 41. In this case, the yarn amount detection sensor 50 can detect that the retention amount of the yarn Y has become the predetermined retention amount, when the light emitted from the light source 53 is reflected by the yarn Y and is detected by the sensor 55.
[0048] The light source 53 may be a light emitting diode (LED), for example. In addition, the sensor 55 may be a photodiode, for example. Other than that, the sensor 55 may be a line sensor, which is a CCD image sensor or a CMOS image sensor having photodiodes arranged in a row to obtain light amount.
[0049] (2-4) Yarn Guide Unit
With reference to Fig. 2, a detailed structure of the yarn guide unit 7 is described, which guides the yarn Y between the yarn feeding unit 6 and the yarn accumulating device 40. The yarn guide unit 7 is disposed in the yarn path (yarn running path) of the yarn Y, and includes an unwinding assist device 7a, a lower yarn feeler 7b, a tension applying unit 7c, a catching device 7d, a yarn splicing device 7e, a yarn monitoring device 7f, a yarn ejection unit 7g, and a yarn guide member 7h.
[0050] When the yarn Y unwound from the yarn feeding bobbin 21 is swung to form a balloon above the yarn feeding bobbin 21, the unwinding assist device 7a assists unwinding of the yarn Y by allowing a moving member 71 to contact the balloon, to appropriately control the size of the balloon.
[0051] The lower yarn feeler 7b is disposed at a position near the unwinding assist device 7a on the downstream side of the unwinding assist device 7a. The lower yarn feeler 7b defines presence or absence of the yarn Y fed from the unwinding assist device 7a.
[0052] The tension applying unit 7c applies a predetermined tension to the running yarn Y. The tension applying unit 7c applies a predetermined tension to the yarn Y based on the tension of the yarn Y detected by the tension sensor. The tension applying unit 7c is constituted as a gate type in which a movable comb tooth member is disposed with respect to a fixed comb tooth member, and applies a predetermined resistance to the yarn Y running between the comb tooth members. The movable comb tooth member is configured to move by a solenoid, for example, so that the comb tooth members are engaged or released. Note that the structure of the tension applying unit 7c is not particularly limited, but may be a disc type tension applying unit, for example.
[0053] The catching device 7d is disposed on the downstream side of the tension applying unit 7c. The catching device 7d includes a first catching unit 72 and a second catching unit 73. In this embodiment, the first catching unit 72 and the second catching unit 73 are integrated, and are constituted as one component. Each of the first catching unit 72 and the second catching unit 73 is connected to a negative pressure source.
[0054] The first catching unit 72 is constituted as a cylindrical member having an opening on the distal end portion. When performing yarn splicing, the first catching unit 72 generates a suction air flow and sucks the internal space of the yarn guide member 7h, to suck and catch the yarn Y on the yarn accumulating device 40 side.
[0055] The second catching unit 73 is constituted as a cylindrical member having an opening on the distal end portion. The second catching unit 73 is disposed in a pivotable manner. The second catching unit 73 pivots between a catching position to catch the yarn Y fed from the unwinding assist device 7a side (the position shown by a solid line in Fig. 2), and a guiding position to guide the yarn Y to the yarn splicing device 7e (the position shown by a broken line in Fig. 2). The catching position may be a standby position of the second catching unit 73.
[0056] The second catching unit 73 in the catching position generates the suction air flow on the distal end side while approaching the yarn path on the downstream side of the lower yarn feeler 7b, to suck and catch the yarn end from the yarn feeding bobbin 21. When a cutter 74 cuts the yarn Y, the second catching unit 73 sucks and catches the yarn end of the cut yarn Y on the yarn feeding bobbin 21 side. In addition, the second catching unit 73 may be constituted to generate the suction air flow on the distal end side, to suck and remove cotton fly or the like adhered to the running yarn Y.
[0057] When the second catching unit 73 catches the yarn Y, if it is just after a new yarn feeding bobbin 21 is supplied to the yarn feeding unit 6, there is disposed an auxiliary blowing unit 75 that blows and sends the yarn end to a downstream side position of the lower yarn feeler 7b (to the distal end of the second catching unit 73).
[0058] The auxiliary blowing unit 75 ejects compressed air into the transport tray 26 formed in a hollow shape and inside of the yarn feeding bobbin 21, to form an air flow at the distal end portion of the yarn feeding bobbin 21, to blow and send the yarn Y of the yarn feeding bobbin 21 to the lower yarn feeler 7b side. If a newly supplied yarn feeding bobbin 21 is supported by the yarn feeding unit 6, the auxiliary blowing unit 75 operates, and hence the yarn end on the yarn feeding bobbin 21 side can be securely sent to the lower yarn feeler 7b side.
[0059] The yarn splicing device 7e performs yarn splicing of the disconnected yarn Y. When cutting the yarn, i.e., when the yarn monitoring device 7f detects a yarn defect and cuts the yarn Y with the cutter 74, or when the yarn breaks, i.e., when the yarn Y being unwound from the yarn feeding bobbin 21 breaks, or when the yarn Y between the yarn feeding bobbin 21 and the yarn accumulating device 40 is disconnected in a case such as replacing the yarn feeding bobbin 21, the yarn splicing device 7e performs yarn splicing between the termination part of the yarn Y on the yarn feeding bobbin 21 side and the termination part of the yarn Y on the yarn accumulating device 40 side. The yarn splicing device 7e is disposed at a position slightly retracted from the yarn path. The yarn splicing device 7e can splice the introduced yarn ends to make the yarn Y continuous. As the yarn splicing device 7e, it is possible to use a device using a fluid such as compressed air, or a mechanical device.
[0060] The yarn monitoring device 7f monitors a thickness or the like of the yarn Y with an appropriate sensor, to detect a yarn defect such as a slub or a foreign object. The cutter 74 is disposed at a position near the yarn monitoring device 7f on the upstream side of the yarn monitoring device 7f. When the yarn monitoring device 7f detects a yarn defect, the cutter 74 promptly cuts the yarn Y. The cutter 74 and the yarn monitoring device 7f are both housed in a housing 76. The housing 76 that houses the yarn monitoring device 7f is disposed on the downstream side of the yarn splicing device 7e.
[0061] The yarn ejection unit 7g is disposed near the tapered portion 41a on one end side of the accumulating roller 41 (the upstream side of the accumulating roller 41), and is constituted of a thin cylindrical member in which the yarn Y can pass. Compressed air can be ejected from an opening of the yarn ejection unit 7g on the yarn feeding unit 6 side, in the direction from the yarn accumulating device 40 toward the yarn feeding unit 6. When the yarn Y is disconnected between the yarn feeding bobbin 21 and the yarn accumulating device 40, the yarn ejection unit 7g ejects air in the direction from the yarn accumulating device 40 toward the yarn feeding unit 6, to suck inside and catch the yarn end of the yarn Y on the yarn accumulating device 40 side, and to blow the same to a guide path of the yarn guide member 7h.
[0062] On the other hand, for normal yarn winding, the yarn ejection unit 7g guides the yarn Y fed from the yarn feeding unit 6 to the tapered portion 41a on one end side of the accumulating roller 41. When the drive motor 45 is driven to rotate the accumulating roller 41 in one direction, the yarn Y is guided by the yarn ejection unit 7g to the tapered portion 41a on one end side of the accumulating roller 41, and is wound sequentially from the one end side (upstream side) of the cylindrical portion 41c by pushing the previous yarn layer. As a result, the yarn Y wound around the outer periphery 41d of the accumulating roller 41 is pushed by a newly wound yarn Y and is sent to the other end side (downstream side) in turn. In this way, on the outer periphery of the cylindrical portion 41c of the accumulating roller 41, the yarn Y is aligned in a helical shape, and regularly wound from one end side to the other end side.
[0063] The yarn ejection unit 7g can be moved by a moving unit 77 between an optimum position for guiding the yarn Y from the yarn feeding unit 6 to the accumulating roller 41 (referred to as a yarn guiding position), and an optimum position for sucking and pulling out the yarn end of the yarn Y accumulated in the yarn accumulating device 40 to guide the same to the yarn splicing device 7e (the guide path of the yarn guide member 7h) (referred to as a yarn pulling-out position).
[0064] The yarn guide member 7h is a curved cylindrical member, and its both ends in the longitudinal direction are provided with openings. One opening of the yarn guide member 7h is disposed to be close to an opening of the yarn ejection unit 7g on the yarn feeding unit 6 side. The other opening is disposed to face the first catching unit 72. Inside the yarn guide member 7h, a guide path is formed. The guide path connects both end openings of the yarn guide member 7h to bypass the yarn monitoring device 7f, the yarn splicing device 7e, and the like. The yarn guide member 7h has a slit penetrating to the guide path over the entire length.
[0065] When the yarn Y is disconnected between the yarn feeding bobbin 21 and the yarn accumulating device 40, the yarn guide member 7h guides the yarn Y, which is blown by the yarn ejection unit 7g to the guide path, along the guide path to the first catching unit 72, and allows the first catching unit 72 to catch the guided yarn Y. Because the yarn guide member 7h has the slit penetrating to the guide path over the entire length, the yarn guide member 7h can pull out the yarn Y caught by the first catching unit 72 from the guide path of the yarn guide member 7h and can guide the same to the yarn splicing device 7e side.
[0066] (2-5) Control Device
Hereinafter, with reference to Fig. 5, a structure of the control device 25 is described. In particular, a control structure is described, which is related to rotation control of the package 30 by the control device 25, and control of the yarn accumulating device 40. Fig. 5 is a diagram illustrating a control structure of the control device 25. The control device 25 includes an information processing unit 25a and a storage unit 25b.
[0067] The information processing unit 25a is constituted of an information processing circuit such as a CPU and the like of the control device 25, and performs various information processing related to the winder unit 2. The information processing unit 25a executes a program stored in the storage unit 25b to perform various information processing. The storage unit 25b is constituted of the storage device of the control device 25, and stores various programs and various parameters or the like related to control of the winder unit 2.
[0068] The storage unit 25b stores at least deceleration rate information IN1, winding end length information IN2, and deceleration stop yarn length information IN3. The deceleration rate information IN1 is information for setting a deceleration rate of the yarn Y in a deceleration stop control. The deceleration stop control is a control for stopping winding of the yarn Y when the package 30 becomes a fully wound state, in which a yarn speed as a running speed of the yarn Y in the yarn running path is decelerated from a yarn speed for forming the package 30 by a constant deceleration rate (i.e., by a deceleration rate set in the deceleration rate information IN1), and the yarn speed becomes zero when the length of the yarn Y wound on the package 30 becomes a length when winding is finished (referred to as a package winding end length). Note that in the deceleration stop control, the yarn speed when the length of the yarn Y wound on the package 30 becomes the package winding end length may have a little increase or decrease (error) from zero.
[0069] The deceleration rate of the yarn Y set in the deceleration rate information IN1, i.e., the deceleration rate of the yarn Y in the deceleration stop control can be changeable depending on formation conditions of the package 30, or the like. In this way, the formation conditions of the package 30 can be set more flexibly.
[0070] The winding end length information IN2 is information for setting the above package winding end length. The package winding end length can be determined as the winding end length information IN2 when the formation conditions of the package 30 are set.
[0071] The deceleration stop yarn length information IN3 is information for determining a yarn length of the yarn Y wound on the package 30 from start to end of the above deceleration stop control (referred to as a deceleration stop yarn length). The inventor experimentally investigated a relationship between a yarn speed just before starting the deceleration stop control and the deceleration stop yarn length, while changing the yarn speed just before starting the deceleration stop control, and found that the deceleration stop yarn length changes linearly with respect to the yarn speed just before starting the deceleration stop control. In other words, the inventor found that y = a*x-b (a and b are positive constants) holds, where x is the yarn speed just before starting the deceleration stop control, and y is the deceleration stop yarn length. The deceleration stop yarn length information IN3 stores this equation or the constants a and b included in this equation.
[0072] As described above, for example, the deceleration stop yarn length information IN3 can be calculated by experimentally obtaining data indicating a relationship between the yarn speed just before starting the deceleration stop control and the deceleration stop yarn length, and by using the obtained data.
[0073] Other than that, for example, it is also possible to theoretically calculate the above equation, based on the yarn speed when forming the package 30 (i.e., the yarn speed just before starting the deceleration stop control) and the deceleration rate set in the deceleration rate information IN1, to determine the deceleration stop yarn length information IN3. Specifically, supposing that V represents the yarn speed when forming the package 30, Ac represents the deceleration rate, and t represents a time period necessary for decelerating the yarn speed from V to zero at the deceleration rate Ac, then the yarn length from start to end of the deceleration stop control is expressed by (Ac*t2)/2. Since the above t can be expressed by V/Ac, the yarn length from start to end of the deceleration stop control can be finally expressed by V2/(2*Ac), using the yarn speed when forming the package 30 and the deceleration rate.
[0074] Note that although not described in detail, the above deceleration rate may be different depending on a type of the yarn wound as the package 30. The deceleration rate is set in advance considering, for example, a thickness, a density, a weight per unit length, and the like of the yarn, and can be appropriately set in accordance with a type of the yarn to be wound.
[0075] The above information processing unit 25a of the control device 25 feeds back the rotation speed of the traverse drum 24 measured by the drum rotation number sensor 63, and controls the rotation speed of the drum drive motor 62 so that the fed-back rotation speed becomes a target rotation speed, thereby it can accurately control the rotation speed of the traverse drum 24.
[0076] In addition, the information processing unit 25a feeds back the rotation speed based on the number of rotations of the accumulating roller 41 measured by the accumulating roller rotation number sensor 46, and controls the rotation speed of the drive motor 45 so that the fed-back rotation speed becomes a target rotation speed, thereby it can accurately control the rotation speed of the accumulating roller 41.
[0077] When performing deceleration of the package 30, the information processing unit 25a feeds back the rotation speed based on the number of rotations of the package 30 measured by the package rotation number sensor 61, and controls the air pressure by the air pressure varying unit 60a so that the fed-back rotation speed becomes a target rotation speed, thereby it can accurately decelerate the package 30.
[0078] In the winder unit 2 having the above structure, by rotating the traverse drum 24, the yarn Y is wound by the traverse drum 24, and after that, the yarn Y is fed from the traverse drum 24 to the package 30 while being traversed. For this reason, the number of rotations of the traverse drum 24 corresponds to the length of the yarn Y wound on the package 30. Therefore, the information processing unit 25a can measure the length of the yarn Y wound on the package 30, based on the number of rotations of the traverse drum 24 measured by the drum rotation number sensor 63.
[0079] In addition, a feed amount of the yarn Y fed to the traverse drum 24 corresponds to an amount of the yarn Y fed from the accumulating roller 41 to the traverse drum 24 after being wound around the accumulating roller 41 of the yarn accumulating device 40. For this reason, the amount of the yarn Y wound around the accumulating roller 41 by rotation of the accumulating roller 41 also corresponds to the length of the yarn Y wound on the package 30. Therefore, the information processing unit 25a can measure the length of the yarn Y wound on the package 30, based on the number of rotations of the accumulating roller 41 measured by the accumulating roller rotation number sensor 46.
[0080] In this embodiment, the information processing unit 25a measures the length of the yarn Y wound on the package 30, by combining measurement of the length of the yarn Y using the drum rotation number sensor 63, and measurement of the length of the yarn Y using the accumulating roller rotation number sensor 46.
[0081] Specifically, when starting forming the package 30, or when restarting forming the package 30 after stopping for running out of yarn, cutting of yarn, replacing of bobbin, or the like, the drum rotation number sensor 63 is used for measuring the length of the yarn Y wound on the package 30, and otherwise the accumulating roller rotation number sensor 46 is used for measuring the length of the yarn Y wound on the package 30. Specifically, when the yarn amount detection sensor 50 detects that the retention amount of the yarn Y on the accumulating roller 41 becomes the predetermined retention amount, the information processing unit 25a switches from the method of measuring the length of the yarn Y using the drum rotation number sensor 63, to the method of measuring the length of the yarn Y using the accumulating roller rotation number sensor 46.
[0082] When starting/restarting forming the package 30, particularly when restarting, a work such as removing the yarn Y is performed, and hence the retention amount of the yarn Y on the accumulating roller 41 is uncertain. For this reason, when starting/restarting forming the package 30, the length of the yarn Y cannot be accurately measured using the accumulating roller rotation number sensor 46. Therefore, when starting/restarting forming the package 30, the drum rotation number sensor 63 is used for measuring the length of the yarn Y, so that the length of the yarn Y wound on the package 30 can be accurately measured.
[0083] On the other hand, during formation of the package 30, particularly if the package 30 has a corn shape (a circular truncated cone shape), the length of the yarn Y cannot be accurately measured using the drum rotation number sensor 63. In contrast, since the accumulating roller 41 has a drum shape (a circular column shape), after the predetermined retention amount of the yarn Y are accumulated on the accumulating roller 41, the length of the yarn Y wound on the package 30 can be accurately measured based on the number of rotations of the accumulating roller 41, regardless of the shape of the package 30.
[0084] Therefore, after the yarn amount detection sensor 50 detects that the retention amount of the yarn Y on the accumulating roller 41 becomes the predetermined retention amount, the length of the yarn Y wound on the package 30 is measured based on the number of rotations of the accumulating roller 41, and hence regardless of the shape of the package 30, the length of the yarn Y wound on the package 30 can be accurately measured.
[0085] Note that the information processing unit 25a can calculate the yarn speed of the yarn Y as the length of the yarn Y wound on the package 30 per predetermined unit time.
[0086] (3) Package Forming Operation
Hereinafter, with reference to Fig. 6, an operation of forming the package 30 using the winder unit 2 is described. Fig. 6 is a flowchart illustrating the operation of forming the package 30 using the winder unit 2. Fig. 6 illustrates a flowchart when forming one package 30. First, the formation conditions of the package 30 are set (Step S1). For instance, using an input device of the machine stand control device 3 or an input device of the control device 25, the formation conditions of the package 30 can be set. Specifically, for example, the yarn length of the yarn Y to be wound on the package 30 (i.e., the package winding end length (the winding end length information IN2)), the yarn speed of the yarn Y during the formation of the package 30, the deceleration rate in the deceleration stop control (i.e., the deceleration rate information IN1), and the like are set. The deceleration rate in the deceleration stop control can be the maximum deceleration rate. The information processing unit 25a of the control device 25 stores the set formation conditions in the storage unit 25b.
[0087] After that, the information processing unit 25a calculates the length of the yarn Y wound on the package 30 when starting the deceleration stop control (referred to as a deceleration start yarn length) (Step S2). Specifically, the deceleration start yarn length is calculated as follows.
[0088] First, the information processing unit 25a refers to the deceleration stop yarn length information IN3 to grasp a relationship between the deceleration stop yarn length and the yarn speed during the formation of the package 30, and calculates the deceleration start yarn length using the relationship. For instance, if the equation y = a*x-b (x is the yarn speed during the formation of the package 30, y is the deceleration stop yarn length, and a and b are positive constants) is grasped from the deceleration stop yarn length information IN3, the information processing unit 25a can calculate the deceleration stop yarn length, by substituting the yarn speed during the formation of the package 30 set in Step S1 (the yarn speed just before starting the deceleration stop control) for x in the above equation.
[0089] Note that if the deceleration stop yarn length is calculated to be zero or less (zero or a negative value) using the above equation, zero is set to the deceleration stop yarn length. In other words, the start timing of the deceleration stop control is set as timing when the length of the yarn Y wound on the package 30 becomes the package winding end length. This occurs in the case where the yarn speed during the formation of the package 30 is calculated to be b/a or less, by solving the above equation for x with setting y = 0.
[0090] If the yarn speed during the formation of the package 30 is small, and even if the deceleration stop control is performed at timing when the length of the yarn Y wound on the package 30 becomes the package winding end length, the length of the yarn Y wound on the package 30 is short when the deceleration stop control is performed. Therefore, even if the deceleration stop control is performed at timing when the length of the yarn Y wound on the package 30 becomes the package winding end length, the length of the yarn Y wound on the package 30 can be regarded to be within the error of the package winding end length.
[0091] For instance, if the equation y = x2/(2*Ac) (x is the yarn speed during the formation of the package 30, y is the deceleration stop yarn length, and Ac is the deceleration rate) is grasped from the deceleration stop yarn length information IN3, the information processing unit 25a can calculate the deceleration stop yarn length, by substituting the yarn speed during the formation of the package 30 set in Step S1 for x in the above equation, and by substituting the deceleration rate set in the deceleration rate information IN1 for Ac in the equation.
[0092] Next, the information processing unit 25a can calculate the deceleration start yarn length by subtracting the deceleration stop yarn length calculated as described above from the package winding end length set in the winding end length information IN2. In other words, it can be calculated by (deceleration start yarn length) = (package winding end length) - (deceleration stop yarn length).
[0093] After calculating the deceleration start yarn length, the formation of the package 30 is started (Step S3). The information processing unit 25a controls the drive motor 45 to rotate the accumulating roller 41, and allows the accumulating roller 41 to wind and accumulate the yarn Y that is supplied from the yarn feeding unit 6 and passes the yarn guide unit 7. In addition, the information processing unit 25a controls the drum drive motor 62 to rotate the traverse drum 24, so that the winding bobbin 22 (the package 30) can rotate. In this way, the yarn Y is wound around the winding bobbin 22 (the package 30) so that the package 30 can be formed.
[0094] When starting forming the package 30, the information processing unit 25a sets a winding speed of the yarn Y on the package 30 by rotation of the traverse drum 24, to be less than the yarn accumulating speed on the accumulating roller 41 by rotation of the accumulating roller 41. In this way, since accumulating of the yarn Y on the accumulating roller 41 has higher priority than supply of the yarn Y from the accumulating roller 41 to the traverse drum 24, the retention amount of the yarn Y on the accumulating roller 41 becomes the predetermined retention amount in a short time, and hence the yarn amount detection sensor 50 detects the yarn Y in a short time. As a result, the method of measuring the length of the yarn Y wound on the package 30 is changed in a short time, form the method using the drum rotation number sensor 63 to the method using the accumulating roller rotation number sensor 46.
[0095] In other words, it is possible to shorten the time period after staring forming the package 30 until the predetermined retention amount of the yarn Y is accumulated on the accumulating roller 41, and hence it is possible to advance the start timing of measuring the length of the yarn Y based on the number of rotations of the accumulating roller 41.
[0096] As described above, during the formation of the package 30, the information processing unit 25a measures the length of the yarn Y wound on the package 30 using the drum rotation number sensor 63 or the accumulating roller rotation number sensor 46 (Step S4).
[0097] After measuring the length of the yarn Y wound on the package 30, the information processing unit 25a determines whether or not the measured length of the yarn Y is the deceleration start yarn length calculated in the above Step S2 (Step S5). If the measured length of the yarn Y is less than the deceleration start yarn length ("No" in Step S5), the formation of the package 30 is continued while measuring the length of the yarn Y wound on the package 30.
[0098] In contrast, if the measured length of the yarn Y is the deceleration start yarn length ("Yes" in Step S5), the information processing unit 25a starts the deceleration stop control (Step S6). Specifically, the information processing unit 25a decelerates the yarn speed of the yarn Y by the deceleration rate set in the deceleration rate information IN1 (e.g., the maximum deceleration rate), from the yarn speed during the formation of the package 30 to zero, to stop rotation of the package 30, thereby finishes the formation of the package 30.
[0099] During execution of the above deceleration stop control, the information processing unit 25a uses both the deceleration of the package 30 by the braking device 60 and the deceleration of the traverse drum 24. The deceleration using these two decelerations is performed specifically as described below.
[0100] First, the information processing unit 25a controls the air pressure varying unit 60a of the braking device 60 to start the deceleration of the package 30 at the set deceleration rate. After that, the information processing unit 25a controls the drum drive motor 62 to start the deceleration of the traverse drum 24. In other words, the information processing unit 25a first decelerates the package 30, and then decelerates the traverse drum 24. In this way, a circumferential speed of the package 30 becomes less than a circumferential speed of the traverse drum 24.
[0101] In this case, the information processing unit 25a adjusts the deceleration rate of the package 30 by controlling the air pressure varying unit 60a of the braking device 60, so that a difference between the circumferential speed of the package 30 and the circumferential speed of the traverse drum 24, i.e., a slippage amount between the package 30 and the traverse drum 24 is within a predetermined range, and controls rotation of the drum drive motor 62 to control the deceleration rate of the traverse drum 24. The tolerance of the slippage amount is preferably 50 to 1000 m/min, and is more preferably 200 to 400 m/min, for example.
[0102] In this way, the deceleration of the package 30 by the braking device 60 and the deceleration of the traverse drum 24 are both used for decelerating the package 30, and hence rotation of the package 30 can be stopped in a short time while suppressing slippage between the package 30 and the traverse drum 24. In other words, for example, the package 30 is not damaged even if the package 30 is stopped in a short time by the maximum deceleration rate.
[0103] In addition, by using both the deceleration of the package 30 by the braking device 60 and the deceleration of the traverse drum 24, it is possible to lift up the package 30 for separating the same from the traverse drum 24, and to stop the package 30 without cutting the yarn Y. In other words, in the winder unit 2 of this embodiment, the package 30 is stooped in the state where the package 30 is contacted with the traverse drum 24, and the yarn Y is connected (is not cut) between the package 30 and the yarn accumulating device 40.
[0104] In the above winder unit 2, which finishes winding of the yarn Y on the package 30 by the deceleration stop control, the start timing of the deceleration stop control is determined by considering not only the length of the yarn Y wound on the package 30 but also the yarn speed during the formation of the package 30, i.e., the yarn speed just before starting the deceleration stop control. Specifically, the deceleration stop yarn length, which is the yarn length of the yarn Y wound on the package 30 from start to end of the deceleration stop control, is calculated based on the yarn speed during the formation of the package 30, and timing when the length of the yarn Y wound on the package 30 becomes the deceleration start yarn length obtained by subtracting the deceleration stop yarn length from the package winding end length is set as the start timing of the deceleration stop control.
[0105] In this way, even if the yarn speed during the formation of the package 30 is different, the yarn winding amount on the package 30 when winding is finished can be substantially constant as the package winding end length. For instance, as illustrated in Fig. 7, if the yarn speed of the yarn Y is V1, the deceleration start yarn length is calculated to be L1, the deceleration stop control is started at time point t1 when the length of the yarn Y wound on the package 30 becomes the deceleration start yarn length L1, and at time point tf1, the yarn speed becomes zero so that the formation of the package 30 is finished, and a winding length of the yarn Y becomes a package winding end length LF. Fig. 7 is a diagram illustrating an example of a temporal change of the winding length of the yarn Y when the yarn speed is different.
[0106] On the other hand, if the yarn speed of the yarn Y is V2 lower than V1, the deceleration start yarn length is calculated to be L2 larger than L1, and time point t2 when the length of the yarn Y wound on the package 30 becomes the deceleration start yarn length L2 is after time point t1. At this time point t2, the deceleration stop control is started, and the yarn speed becomes zero at time point tf2 so that the formation of the package 30 is finished. The winding length of the yarn Y when the formation of the package 30 is finished is the same package winding end length LF as that for the yarn speed V1.
[0107] 2. Other Embodiment
Although an embodiment of the present invention is described above, the present invention is not limited to the above embodiment, but can be variously modified within the scope of the invention without deviating from the spirit thereof. In particular, a plurality of embodiments and variations described in this specification can be arbitrarily combined as necessary.
(A) In the flowchart of Fig. 6, which illustrates the operation of forming the package 30 using the winder unit 2, details of processing in each step and the execution order of the steps can be arbitrarily modified within the scope of the invention without deviating from the spirit thereof.
[0108] (B) In the above embodiment, the yarn speed is decelerated just once from the yarn speed during the formation of the package 30 to zero, to finish the formation of the package 30. However, without limiting to this, the yarn speed may be decelerated to zero by two or more steps of deceleration to finish the formation of the package 30. Specifically, for example, as illustrated in Fig. 8, the formation of the package 30 may be finished by three steps of deceleration. Fig. 8 is a diagram illustrating an example of a temporal change of the yarn speed when the formation of the package 30 is finished by a multiple steps of deceleration.
[0109] More specifically, the yarn speed during the formation of the package 30 is set to V3, the deceleration is started at time point t3, and a constant yarn speed V4 is maintained to continue the formation of the package 30. Further, deceleration is started at time point t4, and a constant yarn speed V5 is maintained to continue the formation of the package 30. After that, as described above, the deceleration stop control is started at time point t5 to decelerate the yarn speed from V5 to zero, and finish the formation of the package 30. In this case, the deceleration start yarn length is calculated as the above winding length of the yarn Y at time point t5.
[0110] By finishing the formation of the package 30 by the above multiple steps of deceleration, compared with the case where the yarn speed is decelerated in one step from the yarn speed during the formation of the package 30 to zero, the yarn speed just before starting the deceleration stop control can be small, and hence the length of the yarn Y wound on the package 30 when the formation of the package 30 is finished can be close to the package winding end length.
[0111] (C) If the sensor 55 of the yarn amount detection sensor 50 is a line sensor, the retention amount of the yarn Y on the accumulating roller 41 can be determined even in a case where the yarn Y is removed due to occurrence of running out of yarn or the like, and hence the length of the yarn Y wound on the package 30 may be measured based on only the number of rotations of the accumulating roller 41.
[0112] (D) In the above first embodiment, the yarn feeding unit 6 feeds the yarn Y that is unwound from the yarn feeding bobbin 21. In other words, the winder unit 2 in the first embodiment is an automatic winder. Without limiting to this, it may be possible to use other types of yarn feeding unit 6. It may be possible that the yarn feeding unit 6 feeds the yarn Y that is spun by power of air, for example. In other words, the winder unit 2 may be an air spinning machine.
[0113] (E) Other than that, the yarn feeding unit 6 may feed the yarn Y that is spun by rotation power of a rotor. In other words, the winder unit 2 may be an open end spinning machine.
[0114] 3. Features of Embodiment
The above embodiment may also be described as follows.
(1) A yarn winding apparatus (e.g., the winder unit 2) includes a yarn feeding unit (e.g., the yarn feeding unit 6), a winding unit (e.g., the package forming unit 8), and a control unit (e.g., the control device 25). The yarn feeding unit is configured to feed yarn (e.g., the yarn Y). The winding unit is configured to wind the yarn to form a package (e.g., the package 30). The control unit is configured to control the winding unit. The control unit performs deceleration stop control on the winding unit. The deceleration stop control is a control for decelerating a yarn speed as a running speed of the yarn from a package forming yarn speed to be zero when a length of the yarn wound on the package becomes a preset package winding end length. In this case, the start timing of the deceleration stop control is determined based on the package winding end length, the package forming yarn speed, and the length of the yarn wound on the package.
[0115] In the above yarn winding apparatus that finishes the yarn winding on the package by the deceleration stop control, because the start timing of the deceleration stop control is determined by considering not only the length of the yarn wound on the package but also the package forming yarn speed, i.e., the yarn speed just before starting the deceleration stop control, the yarn winding amount of the package when winding is finished can be substantially constant as the package winding end length, even if the package forming yarn speed is different.
[0116] (2) In the above yarn winding apparatus of (1), a deceleration rate of the yarn in the deceleration stop control may be set in advance. In this way, since a time period necessary for decelerating the yarn speed from the speed just before starting the deceleration stop control to zero is known, the start timing of the deceleration stop control can be accurately determined.
[0117] (3) In the above yarn winding apparatus of (1) or (2), a deceleration rate of the yarn in the deceleration stop control may be changeable. In this way, package formation conditions can be set more flexibly.
[0118] (4) In the above yarn winding apparatus of any one of (1) to (3), the winding unit may include a rotary drive unit that is configured to rotate the package (e.g., the traverse drum 24). In this case, the control unit may measure the length of the yarn wound on the package based on a drive amount of the rotary drive unit (e.g., the number of rotations of the traverse drum 24). In this way, it is not necessary to provide a sensor that can directly measure the length of the wound yarn.
[0119] (5) In the above yarn winding apparatus of (4), the winding unit may further include a braking device (e.g., the braking device 60) that is configured to decelerate rotation speed of the package. In this case, the control unit may perform the deceleration stop control by using both deceleration of the package by the braking device and deceleration of the rotary drive unit. In this way, rotation of the package can be stopped in a short time while suppressing slippage between the package and the rotary drive unit.
[0120] In addition, by using the deceleration of the package by the braking device and the deceleration of the rotary drive unit, when the deceleration stop control is finished, the package is contacted with the rotary drive unit, and the yarn is connected. In other words, when the deceleration stop control is finished, although lifting up for separating the package from the rotary drive unit is not performed, by determining the start timing of the deceleration stop control as described above, the yarn winding amount of the package when winding is finished can be substantially constant as the package winding end length, without the lifting up.
[0121] (6) The above yarn winding apparatus of any one of (1) to (5) may further include an accumulating roller (e.g., the accumulating roller 41). The accumulating roller is disposed between the yarn feeding unit and the winding unit in a yarn running direction, to wind and temporarily accumulate the yarn. In this case, the control unit may measure the length of the yarn wound on the package based on the number of rotations of the accumulating roller. In this way, regardless of a shape of the package, the length of the yarn wound on the package can be accurately measured.
[0122] (7) The above yarn winding apparatus of (6) may further include a yarn amount detection sensor (e.g., the yarn amount detection sensor 50). The yarn amount detection sensor is configured to detect that a yarn retention amount on the accumulating roller becomes a predetermined retention amount. In this case, the control unit may measure the length of the yarn wound on the package based on the number of rotations of the accumulating roller, after the yarn amount detection sensor detects that the yarn retention amount on the accumulating roller becomes the predetermined retention amount. When starting (restarting) forming the package, the yarn retention amount on the accumulating roller is uncertain (varied), and hence the length of the yarn measured based on the number of rotations of the accumulating roller from the start of formation is not accurate. Therefore, as described above, by measuring the length of the yarn based on the number of rotations of the accumulating roller after the yarn retention amount on the accumulating roller has become the predetermined retention amount, it is possible to measure the length of the yarn more accurately.
[0123] (8) In the above yarn winding apparatus of (7), the control unit may set a yarn winding speed on the package to be lower than a yarn accumulating speed on the accumulating roller, when starting forming the package. In this way, a time period after starting forming the package until the predetermined retention amount of yarn is accumulated on the accumulating roller can be shortened, and hence it is possible to advance start timing of measuring the length of the yarn based on the number of rotations of the accumulating roller.
[0124] (9) In the above yarn winding apparatus of any one of (1) to (8), the control unit may calculate a deceleration stop yarn length as a yarn length of the yarn wound on the package from start to end of the deceleration stop control, based on the yarn speed during formation of the package, and when the length of the yarn wound on the package becomes a deceleration start yarn length obtained by subtracting the deceleration stop yarn length from the package winding end length, the control unit may determine to be the start timing of the deceleration stop control. In this way, the start timing of the deceleration stop control can be accurately determined, based on the package winding end length, the package forming yarn speed, and the length of the yarn wound on the package.
[0125] (10) In the above yarn winding apparatus of (9), the deceleration stop yarn length may change linearly with respect to the package forming yarn speed. In this way, the deceleration stop yarn length can be easily calculated.

INDUSTRIAL APPLICABILITY
[0126] The present invention can be widely applied to yarn winding apparatuses.
, Claims:We claim:

1. A yarn winding apparatus (2) comprising:
a yarn feeding unit (6) configured to feed yarn (Y);
a winding unit (8) configured to wind the yarn (Y) to form a package (30; and
a control unit (25) configured to control the winding unit (8), wherein
the control unit (25) performs deceleration stop control on the winding unit (8), for decelerating a yarn speed as a running speed of the yarn (Y) from the yarn speed during formation of the package (30), to be zero when a length of the yarn (Y) wound on the package (30) becomes a preset package winding end length, and
the start timing of the deceleration stop control is determined based on the package winding end length, the yarn speed during formation of the package (30), and the length of the yarn (Y) wound on the package (30).

2. The yarn winding apparatus (2) as claimed in claim 1, wherein a deceleration rate of the yarn (Y) in the deceleration stop control is set in advance.

3. The yarn winding apparatus (2) as claimed in claim 1 or 2, wherein a deceleration rate of the yarn (Y) in the deceleration stop control is changeable.

4. The yarn winding apparatus (2) as claimed in one of claims 1 to 3, wherein
the winding unit (8) includes a rotary drive unit (24) configured to rotate the package (30), and
the control unit (25) measures the length of the yarn (Y) wound on the package (30) based on a drive amount of the rotary drive unit (24).

5. The yarn winding apparatus (2) as claimed in claim 4, wherein
the winding unit (8) further includes a braking device (60) configured to decelerate rotation speed of the package (30),
the control unit (25) performs the deceleration stop control by using both deceleration of the package (30) by the braking device (60) and deceleration of the rotary drive unit (24), and
when the deceleration stop control is finished, the package (30) is contacted with the rotary drive unit (24), and the yarn (Y) is connected.

6. The yarn winding apparatus (2) as claimed in one of claims 1 to 5, further comprising an accumulating roller (41) disposed between the yarn feeding unit (6) and the winding unit (8) in a yarn running direction, and configured to wind and temporarily accumulate the yarn (Y), wherein
the control unit (25) measures the length of the yarn (Y) wound on the package (30) based on the number of rotations of the accumulating roller (41).

7. The yarn winding apparatus (2) as claimed in claim 6, further comprising a yarn amount detection sensor (59) configured to detect that a retention amount of the yarn (Y) on the accumulating roller (41) becomes a predetermined retention amount, wherein
the control unit (25) measures the length of the yarn (Y) wound on the package (30) based on the number of rotations of the accumulating roller (41), after the yarn amount detection sensor (59) detects that the retention amount of the yarn (Y) on the accumulating roller (41) becomes the predetermined retention amount.

8. The yarn winding apparatus (2) as claimed in claim 7, wherein the control unit (25) sets a winding speed of the yarn (Y) on the package (30) to be lower than a retailing speed of the yarn (Y) on the accumulating roller (41), when starting forming the package (30).

9. The yarn winding apparatus (2) as claimed in one of claims 1 to 8, wherein
the control unit (25) calculates a deceleration stop yarn length as a yarn length of the yarn (Y) wound on the package (30) from start to end of the deceleration stop control, based on the yarn speed during formation of the package (30), and
when the length of the yarn (Y) wound on the package (30) becomes a deceleration start yarn length obtained by subtracting the deceleration stop yarn length from the package winding end length, the control unit (25) determines to be the start timing of the deceleration stop control.

10. The yarn winding apparatus (2) as claimed in claim 9, wherein the deceleration stop yarn length changes linearly with respect to the yarn speed during formation of the package (30).