EP2366649A2

EP2366649A2 - Yarn winding machine

Info

Publication number: EP2366649A2
Application number: EP11156725A
Authority: EP
Inventors: Yasunobu Tanigawa; Katsufumi Muta; Tetsuya Namikawa; Hideshige Mori
Original assignee: Murata Machinery Ltd
Current assignee: Murata Machinery Ltd
Priority date: 2010-03-17
Filing date: 2011-03-03
Publication date: 2011-09-21
Also published as: CN201961898U; JP2011195216A; EP2366649A3; CN102190209A

Abstract

An automatic winder includes a cradle, a contact roller (29) and a traverse device. The cradle rotatably supports a winding bobbin (22) around which a yarn is wound into a package (30). The contact roller (29) rotates while making contact with the package (30). The traverse device is provided independently from the contact roller (29), and traverses the yarn with respect to a surface of the package (30). The contact roller 29 is formed as a taper shape. A larger and smaller diameter ratio (d₂/d₁) of the contact roller (29) is smaller than a larger and smaller diameter ratio (D₂/D₁) of the winding bobbin (22).

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a yarn winding machine. More specifically, the present invention relates to a structure of a contact roller that rotates while making contact with a package of a yarn, in the yarn winding machine provided with a traverse device that reciprocates a traverse guide to traverse the yarn guided by the traverse guide.

2. Description of the Related Art

There has been known a yarn winding machine provided with a traverse device that traverses a yarn with respect to a surface of a package by reciprocating a traverse guide. Such a yarn winding machine is disclosed, for example, in Japanese Unexamined Patent Publication No. 2006-298499 . This type of yarn winding machine includes a contact roller (a guide roller in Japanese Unexamined Patent Publication No. 2006-298499 ) that rotates while making contact with a surface of a package in order to prevent the yarn from being swung excessively and the traverse from being unstable. Such a contact roller is typically formed cylindrical (or columnar) as illustrated in the drawings of Japanese Unexamined Patent Publication No. 2006-298499 .
Hereinafter, a conventional yarn winding machine will be briefly described with reference to FIGS. 6 and 7. This type of yarn winding machine includes a contact roller 103, a traverse arm 105, a traverse arm driving motor 106 and a yarn guiding member 107. The contact roller 103 makes contact with a surface of a bobbin 100 (or a package 101). The traverse guide 104 is formed at a tip end of the traverse arm 105. The yarn guiding member 107 guides a yarn 110 to a position at which the traverse guide 104 can catch the yarn 110.
In the yarn winding machine as described above, any one of the package 101 and the contact roller 103 is positively driven and rotated, and the other is passively driven and rotated. In the following, a description will be made of a structure in which the package 101 is positively driven and the contact roller 103 is passively driven.
As illustrated in a side view in FIG. 7, the yarn 110 is wound around the surface of the package 101 by rotating the bobbin 100 (or the package 101). As illustrated by an arrow in FIG. 6, the traverse guide 104 can be reciprocated in a circular arc shape by reciprocating and swinging the traverse arm 105 right and left by the traverse arm driving motor 106. The yarn 110 can be wound around the surface of the rotating package 101 while being traversed right and left (in a width direction of the package 101), by reciprocating the traverse guide 104 in a circular arc shape under a state in which the yarn 110 is caught by the traverse guide 104, while rotating the bobbin 100 (or the package 101).
As illustrated in FIG. 7, the bobbin 100 (or the package 101) and the contact roller 103 rotate in a contact state. At this time, a portion of the yarn 110 between the package 101 and the traverse guide 104 makes contact with a peripheral surface of the contact roller 103. Accordingly, a friction force acts between the yarn 110 immediately before being wound into the package 101 and the peripheral surface of the contact roller 103.
In the following description, temporal contact of the yarn 110 with the outer peripheral surface of the contact roller 103 as described above is referred to as "printing", and a length of the portion of the yarn 110 that is in contact with the contact roller 103 as described above is referred to as "print length". The traverse of the yarn 110 can be stabilized by printing the yarn 110 on the contact roller 103. A distance between the traverse guide 104 and a point at which the yarn 110 makes contact with the surface of the contact roller 103 is referred to as "free length".
In view of accurately performing the traverse of the yarn 110, it is preferable that no slip is generated between the contact roller 103 and the yarn 110 which is printed on the contact roller 103. The yarn 110 which is printed on the contact roller 103 is fed towards the package 101 by a rotation of the contact roller 103, and is wound around the surface of the package 101 by a rotation of the package 101. Accordingly, when a speed at which the contact roller 103 feeds the yarn 110 is different from a speed at which the package 101 winds the yarn 110, the yarn 110 may frequently slip on the contact roller 103. The speed at which the contact roller 103 feeds the yarn 110 substantially coincides with a peripheral speed of the contact roller 103. The speed at which the package 101 winds the yarn 110 substantially coincides with a peripheral speed of the package 101. Accordingly, slip tends to be generated when the peripheral speed of the package 101 is different from the peripheral speed of the contact roller 103.
In the case of a cheese package as illustrated in FIG. 8A, the peripheral speed of the package is the same at any position on the surface of the package. Since the contact roller is passively driven and rotated by driving and rotating the package, the peripheral speed of the contact roller substantially coincides with the peripheral speed of the package. In such a case, regardless of a position where the yarn is traversed on the surface of the package by the traverse arm, the speed at which the yarn is fed from the contact roller substantially coincides with the speed at which the package winds the yarn. Accordingly, when the yarn is wound into the cheese package, the yarn does not slip frequently on the contact roller.
On the other hand, in the case of a cone winding package as illustrated in FIG. 8B, the peripheral speed is larger in a larger diameter side of the package and the peripheral speed is smaller in a smaller diameter side of the package, with respect to the peripheral speed of a center portion in a width direction of the package. A position at which the peripheral speed of the package is substantially equal to the peripheral speed of the contact roller is referred to as "uniform speed point". When the yarn is wound into the cone winding package, the peripheral speed of the package becomes smaller than the peripheral speed of the contact roller at a position which is closer to the smaller diameter side than the uniform speed point. As a result, if the yarn is traversed to the smaller diameter side of the cone winding package, the speed at which the package winds the yarn becomes slower than the speed at which the yarn is fed from the contact roller, and a tension of the yarn between the package and the contact roller becomes low.
When the yarn is wound into the cone winding package, at a position which is closer to the larger diameter side than the uniform speed point, the peripheral speed of the package becomes larger than the peripheral speed of the contact roller. Therefore, if the yarn is traversed to the larger diameter side of the cone winding package, the speed at which the package winds the yarn becomes higher than the speed at which the yarn is fed from the contact roller. Accordingly, the tension of the yarn between the package and the contact roller becomes large. As a result, the yarn is pulled, and a slip is generated between the contact roller and the yarn.
As described above, when the yarn is wound into the cone winding package, the tension of the yarn wound into the package fluctuates between the larger diameter side and the smaller diameter side of the package. Specifically, with respect to the winding tension at the uniform speed point, the winding tension in the smaller diameter side of the package becomes lower, and the winding tension in the larger diameter side of the package becomes higher. As a result, stitching tends to be generated in the larger diameter side of the package, and a defective package may be produced.
The above problems are caused by the peripheral speed difference generated between the package and the contact roller, since the contact roller is formed cylindrical (or columnar) while the package is formed conical. In this regard, Japanese Unexamined Utility Model Publication No. 3-49259 discloses a contact roller (a package driving drum) which is formed as a tapered shape (a conical shape) in conformity to a shape of a bobbin (a paper tube). Japanese Unexamined Utility Model Publication No. 3-49259 states that a slip between the paper tube and the driving drum can accordingly be reduced.
When forming the conical package in the yarn winding machine, various shaped winding bobbins are used according to an intended use of the package, a yarn type or the like. However, since the contact roller (the package driving drum) described in Japanese Unexamined Utility Model Publication No. 3-49259 is formed in conformity to the shape of the bobbin (the paper tube), one contact roller can correspond to only one type of winding bobbin. Therefore, in the structure of Japanese Unexamined Utility Model Publication No. 3-49259 , since a different contact roller needs to be prepared per bobbin having a different shape, there has been a problem in terms of costs. Since the contact roller needs to be replaced every time the shape of the bobbin is changed, there has been a problem that a burden is imposed on an operator.
In the structure of Japanese Unexamined Utility Model Publication No. 3-49259 , the slip can be prevented at the start of winding of the package, however, an assumption can be made that the slip increases as the yarn is wound into the bobbin and the diameter of the package increases. This is because since a ratio of the diameter of the larger diameter side with respect to the diameter of the smaller diameter side of the package changes accompanying an increase in the diameter of the package, the shape of the package does not coincide with the shape of the contact roller in Japanese Unexamined Utility Model Publication No. 3-49259 . As described above, in the structure of Japanese Unexamined Utility Model Publication No. 3-49259 , since the slip frequently generates accompanying an increase in the diameter of the package, quality of the finally produced package is unsatisfactory and there was room for improvement.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a yarn winding machine which can form a high quality cone winding package for various bobbin shapes.
According to an aspect of the present invention, a yarn winding machine includes a bobbin supporting section, a contact roller and a traverse device. The bobbin supporting section rotatably supports a bobbin around which a yarn is wound into a package. The contact roller rotates while making contact with the package. The traverse device is provided independently from the contact roller and traverses the yarn with respect to a surface of the package. The contact roller is formed in a taper shape. A ratio of a diameter of a larger diameter end with respect to a diameter of a smaller diameter end of the contact roller is smaller than a ratio of a diameter of a larger diameter end with respect to a diameter of a smaller diameter end of the bobbin.
By forming the contact roller as the taper shape as described above, a peripheral speed difference generated between the contact roller and the cone winding package can be reduced as compared to the structure in which the shape of the contact roller is cylindrical. Accordingly, stitching or the like in the larger diameter side which tends to be generated during winding of the cone winding package can be prevented, and a high quality package can be formed. As the diameter of the cone winding package increases, the ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end becomes smaller. Accordingly, by making the ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end of the contact roller to be smaller than the ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end of the bobbin, the peripheral speed difference generated between the contact roller and the cone winding package can be prevented from becoming excessively large even if the diameter of the package increases. In the conventional structure (Japanese Unexamined Utility Model Publication No. 3-49259 ) in which the contact roller is formed in conformity to the shape of the bobbin, a different contact roller needs to be prepared per bobbin having a different shape. However, according to the structure described above, the contact roller can be used for a plurality of types of bobbins as long as the ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end of the bobbin is larger than that of the contact roller.
In the above yarn winding machine, the bobbin supporting section has a smaller diameter side supporting section and a larger diameter side supporting section to support a conical bobbin. The smaller diameter end of the contact roller is arranged with respect to the smaller diameter side supporting section. The larger diameter end of the contact roller is arranged with respect to the larger diameter side supporting section. Accordingly, the peripheral speed difference between the contact roller and the bobbin (or the package) can be made small.
In the above yarn winding machine, the ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end of the contact roller is preferably at least 1.1 and less than 1.8. By making the ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end to be at least 1.1, the contact roller having a taper to some degree can be formed. The ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end of the general conical bobbin is at most 1.8. Accordingly, by making the ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end of the contact roller to be less than 1.8, the ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end of the contact roller can be made smaller than the ratio of the general conical bobbin. As a result, even when winding any type of conical bobbin among the generally existing plurality of types of conical bobbins, a high quality package can be wound by the yarn winding machine while maintaining the peripheral speed difference generated between the contact roller and the cone winding package to be small.
In the above yarn winding machine, the bobbin supporting section can preferably support at least a bobbin of which the ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end is 1.6. Since the ratio of the larger diameter end with respect to the diameter of the smaller diameter end is 1.6 in the commonly used conical bobbin, the yarn winding machine is preferable to be structured to support the bobbin of this type.
In the above yarn winding machine, the bobbin supporting section can preferably support at least a bobbin of which the ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end is 1.8. Since the ratio of the larger diameter end with respect to the diameter of the smaller diameter end is 1.8 in the commonly used conical bobbin, the yarn winding machine is preferable to be structured to support the bobbin of this type.
Preferably, the above yarn winding machine further includes a package driving section adapted to directly drive and rotate the bobbin. When passively rotating the bobbin (or the package) by driving and rotating the contact roller, the diameter of the contact roller needs to be made large to some degree to reliably drive the bobbin (or the package). However, according to the above structure, the size of the contact roller does not need to be made large, and the contact roller can be formed compact.
In the above yarn winding machine, the traverse device includes a traverse arm and a traverse guide arranged at a tip end of the traverse arm. The traverse device traverses the yarn with respect to the surface of the package by reciprocating the traverse guide by rotationally driving the traverse arm with its base end as a center under a state in which the yarn is engaged with the traverse guide.
In other words, in the traverse device having the traverse arm, a print length tends to become longer in both end portions of a traverse stroke when the yarn is being traversed. As a result, a slip of the yarn which is printed on the contact roller particularly tends to be generated. Accordingly, an effect of improving package quality can be particularly significantly obtained by adapting the structure of the present invention in the yarn winding machine provided with the traverse device having the traverse arm and reducing the slip of the yarn.
The above yarn winding machine further includes a traverse driving section adapted to drive and rotate the traverse arm. When viewed from a direction of a straight line connecting both ends of a traverse stroke, a driving shaft center of the traverse driving section and an extended line of a yarn path of the yarn wound into the package intersect while forming an acute angle or are parallel to one another. Accordingly, since bending of the yarn by the traverse guide can be reduced particularly at the end portion of the traverse stroke, a load applied to the yarn wound into the package can be reduced, and quality of the package can be further improved.
In the above yarn winding machine, when viewed from the direction of the straight line connecting both ends of the traverse stroke, an imaginary line passing through the base end of the traverse arm and the traverse guide is preferably substantially perpendicular to the yarn path. Accordingly, since the bending of the yarn by the traverse guide can be reduced particularly at the end portion of the traverse stroke, the load applied to the yarn wound into the package can be reduced, and the quality of the package can be further improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front view and a block diagram illustrating a structure of a winder unit provided in an automatic winder according to an embodiment of the present invention;
FIG. 2 is a schematic side view of a traverse device;
FIG. 3 is a view illustrating taper angles, and diameter of a larger diameter end and a smaller diameter end of a winding bobbin and a contact roller;
FIG. 4 is a chart illustrating a result obtained by forming a package by using different contact rollers;
FIG. 5 is a schematic front view and a block diagram illustrating a structure of a winder unit according to a modified example;
FIG. 6 is a front view illustrating a structure of a conventional traverse device and a conventional contact roller;
FIG. 7 is a side view illustrating the structure of the conventional traverse device and the conventional contact roller; and
FIG. 8 is a view illustrating a peripheral speed difference between the package and the contact roller.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Next, a description will be made of an embodiment according to the present invention with reference to the accompanying drawings. A winder unit 10 illustrated in FIG. 1 forms a package 30 having a predetermined shape by winding a yarn 20 unwound from a supply yarn bobbin 21 around a winding bobbin 22 while traversing the yarn 20. An automatic winder (a yarn winding machine) according to the present embodiment includes a plurality of winder units 10 which are arranged in line, and a main control device (not illustrated) which is arranged in one end in a direction in which the winder units 10 are arranged.
Each of the winder units 10 includes a winding unit main body 16, and a unit control section 50.
The unit control section 50 includes, for example, a Central Processing Unit (CPU), a Random Access Memory (RAM) and a Read Only Memory (ROM). A program for controlling various components in the winding unit main body 16 is recorded in the ROM.
In the winding unit main body 16, a yarn unwinding assisting device 12, a tension applying device 13, a splicer device 14 and a clearer (yarn quality measuring device) 15 are arranged in this order from the supply yarn bobbin 21 side in a yarn traveling pathway between the supply yarn bobbin 21 and the winding bobbin 22.
The yarn unwinding assisting device 12 controls a regulating member 40 to make contact with a balloon which is formed at an upper portion of the supply yarn bobbin 21 by the yarn 20 unwound from the supply yarn bobbin 21 being swung. Accordingly, the yarn unwinding assisting device 12 assists the unwinding of the yarn 20 by controlling the balloon to an appropriate size. A sensor (not illustrated) for detecting a chase portion of the supply yarn bobbin 21 is provided in proximity of the regulating member 40. When the sensor detects lowering of the chase portion, the regulating member 40 is lowered following thereto, for example, by an air cylinder (not illustrated).
The tension applying device 13 applies a predetermined tension to a traveling yarn 20. As the tension applying device 13, for example, a gate type can be used in which movable comb teeth 37 are arranged with respect to fixed comb teeth 36. The movable comb teeth 37 can be rotated, for example, by a rotary solenoid 38 so that the comb teeth are engaged with or disengaged from one another. A prescribed tension can be applied to the winding yarn 20 by the tension applying device 13 to improve quality of the package 30. In place of the gate type tension applying device, for example, a disc type tension applying device may be used as the tension applying device 13.
The clearer 15 includes a clearer head 49 and an analyzer 53. A sensor (not illustrated) for detecting a thickness of the yarn 20 is arranged in the clearer head 49. The analyzer 53 processes a yarn thickness signal from the sensor. The clearer 15 detects a yarn defect such as slub by monitoring the yarn thickness signal from the sensor. A cutter 39 is provided near the clearer head 49, and immediately cuts the yarn 20 when the clearer 15 detects the yarn defect. The analyzer 53 may be provided in a unit control section 50.
The splicer device 14 connects a lower yarn from the supply yarn bobbin 21 and an upper yarn from the package 30 when the yarn is cut due to detection of a yarn defect by the clearer 15, or when the yarn is broken during the unwinding of the yarn 20 from the yarn supplying bobbin 21. As a yarn splicing device that connects the upper yarn and the lower yarn, a mechanical type yarn splicing device or a yarn splicing device using a fluid such as compressed air or the like can be used.
A lower yarn guiding pipe 25 is provided below the splicer device 14, and catches the lower yarn from the supply yarn bobbin 21 to guide the lower yarn to the splicer device 14. An upper yarn guiding pipe 26 is provided above the splicer device 14, and catches the upper yarn from the package 30 to guide the upper yarn to the splicer device 14. The lower yarn guiding pipe 25 and the upper yarn guiding pipe 26 can rotate around shafts 33 and 35, respectively. A suction port 32 is formed at a tip end of the lower yarn guiding pipe 25. A suction mouth 34 is provided at a tip end of the upper yarn guiding pipe 26. An appropriate negative pressure source is respectively connected to the lower yarn guiding pipe 25 and the upper yarn guiding pipe 26. A suction flow can be generated in the suction port 32 and the suction mouth 34 to suck and catch yarn ends of the upper yarn and the lower yarn.
The winding unit main body 16 includes a cradle (a bobbin supporting section) 23, and a contact roller 29. The cradle 23 detachably supports a winding bobbin (a paper tube or a core tube) 22. The contact roller 29 can be rotated while making contact with a peripheral surface of the winding bobbin 22 or a peripheral surface of the package 30. In the winding unit main body 16, an arm type traverse device 27 is provided near the cradle 23. The winding unit main body 16 winds the yarn 20 into the package 30 while traversing the yarn 20 with respect to the surface of the package 30 by the traverse device 27.
The cradle 23 has a smaller diameter side supporting arm (a smaller diameter side supporting section) 23a which supports a smaller diameter side of the conical (tapered) winding bobbin 22, and a larger diameter side supporting arm (a larger diameter side supporting section) 23b which supports a larger diameter side of the winding bobbin 22. The cradle 23 rotatably supports the conical winding bobbin 22 by holding the conical winding bobbin 22 by the smaller diameter side supporting arm 23a and the larger diameter side supporting arm 23b. More specifically, the cradle 23 can support a winding bobbin in which a ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end is 1.6 and a winding bobbin in which the ratio is 1.8. These winding bobbins are generally used as the conical winding bobbin (in other words, the general conical winding bobbin can be supported by the cradle 23 according to the present embodiment). The cradle 23 can also support a cylindrical winding bobbin.
The cradle 23 can swing around a rotating shaft 48. An increase in a yarn layer diameter of the package 30 accompanying the winding of the yarn 20 around the winding bobbin 22 can be absorbed by the swinging of the cradle 23. In other words, even if the yarn layer diameter of the package 30 changes by the yarn 20 being wound, the surface of the package 30 can be appropriately made in contact with the contact roller 29. The cradle 23 and the traverse device 27 can form the conical package 30 as illustrated in FIG. 1 by winding the yarn 20 around the conical winding bobbin 22.
A package driving motor (a package driving section) 41 is attached to the cradle 23. The yarn 20 can be wound around the surface of the winding bobbin 22 (or the surface of the package 30) by driving and rotating the winding bobbin 22 by the package driving motor 41. A motor shaft of the package driving motor 41 is coupled to the winding bobbin 22 so as not to relatively rotate when the winding bobbin 22 is supported by the cradle 23 (so-called direct drive type). An operation of the package driving motor 41 is controlled by a unit control section 50. A package driving motor control section which is independent from the unit control section 50 may be provided, and the operation of the package driving motor 41 may be controlled by the package driving motor control section.
An angle sensor 44 for detecting an angle (a swing angle around the rotating shaft 48) of the cradle 23 is attached to the rotating shaft 48. The angle sensor 44 is, for example, a rotary encoder, and transmits an angle signal corresponding to the angle of the cradle 23 to the unit control section 50. The angle of the cradle 23 changes accompanying an increase in the diameter of the package 30. The diameter of the yarn layer of the package 30 can be detected by detecting the angle by the angle sensor 44. By controlling the traverse device 27 according to the yarn layer diameter of the package 30, the traverse of the yarn 20 can be appropriately carried out by the traverse device 27. As a method of detecting the diameter of the yarn layer of the package 30, appropriate structures can be adapted as long as the method can detect the diameter of the package, for example, a structure using a Hall IC, an absolute type encoder and the like, in addition to the angle sensor 44.
Next, a description will be made of the traverse device 27. The traverse device 27 includes a traverse arm 28, a traverse guide 11, a traverse arm driving motor 45 and a yarn guiding member 52 as main components. A side view of the traverse device 27 is illustrated in FIG. 2.
The traverse arm 28 is formed as an elongate arm which is formed capable of swinging around a supporting shaft. The traverse guide 11 is held at a tip end of the traverse arm 28, and is formed as a hook shape so that the yarn 20 can be engaged. A base end side of the traverse arm 28 is fixed to a driving shaft center 45a of the traverse arm driving motor 45. The traverse arm driving motor 45 is provided for driving the traverse arm 28, and is a servo motor (an appropriate motor, for example, a brushless DC motor, a stepping motor, a voice coil motor or the like can be used as the servo motor).
The traverse device 27 reciprocates and swings the traverse arm 28 as illustrated by arrows in FIG. 1 by driving the traverse arm driving motor 45 under a state in which the yarn 20 is engaged with the traverse guide 11. Accordingly, the traverse device 27 traverses the yarn 20 with respect to the surface of the package 30 in a lateral direction by reciprocating the traverse guide 11 in the lateral direction (a width direction of the package 30). In the following description, a locus in which the traverse guide 11 reciprocates is referred to as "traverse stroke". Since the traverse guide 11 reciprocates in the lateral direction as described above, the side view, for example, FIG. 2 can be referred to as a view as viewed from a direction of a straight line connecting both ends of the traverse stroke.
An operation of the traverse arm driving motor 45 is controlled by a traverse control section (not illustrated). The operation of the traverse arm driving motor 45 may be controlled by the unit control section 50. The yarn guiding member 52 is arranged upstream in a yarn traveling direction with respect to the traverse guide 11. The yarn guiding member 52 makes a yarn path of the yarn 20 located upstream of the yarn guiding member 52 in the yarn traveling direction to bend towards the contact roller 29. Accordingly, the yarn guiding member 52 guides the yarn 20 so that the traverse guide 11 can catch the yarn 20.
As illustrated in FIG. 2, when viewed from the direction of the straight line connecting both ends of the traverse stroke, the driving shaft center 45a of the traverse arm driving motor 45 is arranged to have an angle close to parallel with respect to the yarn path of the yarn 20 located upstream of the yarn guiding member 52 (such that an extended line of the driving shaft center 45a and the yarn path of the yarn 20 form an acute angle). When viewed from the direction of the straight line connecting both ends of the traverse stroke, an imaginary line connecting the base end of the traverse arm 28 and the traverse guide 11 is arranged to be substantially orthogonal to the extended line of the yarn path of the yarn 20 located upstream of the yarn guiding member 52. The yarn path of the yarn 20 is substantially perpendicular to an installation surface of the winder unit 10 (a horizontal surface in the present embodiment). Accordingly, in the automatic winder according to the present embodiment, the traverse guide 11 is structured to reciprocate within a plane which is substantially parallel to the installation surface of the winder unit 10 (the horizontal surface in the present embodiment).
In this regard, in the conventional traverse device, as illustrated in FIG. 7, the driving shaft center 106a of the traverse arm driving motor 106 is arranged substantially orthogonal to the yarn path of the yarn 110 located upstream of the yarn guiding member 107. In the conventional traverse device, when viewed from the direction of the straight line connecting both ends of the traverse stroke, the imaginary line connecting the base end of the traverse arm 105 and the traverse guide 104 is arranged to be substantially parallel to the imaginary line of the yarn 110 located upstream of the yarn guiding member 107. That is, in the conventional traverse device, the traverse guide 104 is structured to reciprocate within the plane which is substantially orthogonal to the installation surface of the winder unit. In this conventional structure, the yarn path is greatly bent by the yarn guiding member 107, and a load is applied to the yarn 110. The bending of the yarn path tends to be particularly great at both right and left ends of the traverse stroke. In the conventional traverse device, since the traverse guide 104 carries out the circular arc motion within the vertical plane, a vertical position of the traverse guide 104 greatly differs at the center position and the right and left ends of the traverse stroke. Therefore, at the traverse stroke ends, the yarn 110 is pulled downward by the traverse guide 104, whereby excess force is applied to the yarn 110. As a result, the end surface of the formed package 101 may be hardened.
On the other hand, the bending of the yarn path by the yarn guiding member 52 can be reduced, as compared to the conventional traverse device, by structuring the traverse guide 11 to reciprocate within the plane which is substantially parallel to the installation surface of the winder unit 10, as in the traverse device 27 according to the present embodiment. An effect of reducing the bending of the yarn path can be greatly obtained particularly at both the right and left ends of the traverse stroke in which the bending of the yarn path becomes maximum. In the traverse device 27 according to the present embodiment, since the vertical position of the traverse guide 11 does not change so much between the center position and the right and left ends of the traverse stroke, the yarn 20 is not pulled downward by the traverse guide 11. As a result, hardening of the end surface of the package 30 due to the yarn 20 being pulled downward can be reduced. According to the traverse device 27 of the present embodiment, since excess force is not applied to the yarn 20, the slip of the yarn 20 printed on the contact roller 29 can be reduced, and accurate traverse can be performed. As a result, the high quality package 30 can be formed.
Next, a description will be made of the contact roller 29. The contact roller 29 is arranged facing the winding bobbin 22, which is supported by the cradle 23. The contact roller 29 is rotated by driving and rotating the winding bobbin 22 under a state in which an outer peripheral surface of the winding bobbin 22 (or the package 30) is in contact with an outer peripheral surface of the contact roller 29.
As illustrated in FIG. 1, the contact roller 29 in the present embodiment is formed as a taper shape (a conical shape). More specifically, the contact roller 29 is formed such that a cross-sectional shape in a plane passing through the axis of the contact roller 29 is trapezoidal (the contact roller 29 may be formed hollow). The smaller diameter end of the contact roller 29 is arranged so as to be located close to the smaller diameter side supporting arm 23a. The larger diameter end of the contact roller 29 is arranged so as to be located close to the larger diameter side supporting arm 23b. That is, the contact roller 29 is arranged such that the larger diameter side of the contact roller 29 is located close to the larger diameter side of the winding bobbin 22, and the smaller diameter side of the contact roller 29 is located close to the smaller diameter side of the winding bobbin 22. With this structure, a peripheral speed of the contact roller 29 can be made smaller at the bobbin smaller diameter side in which the peripheral speed of the winding bobbin 22 (or the package 30) becomes smaller, and the peripheral speed of the contact roller 29 can be made larger at the bobbin larger diameter side in which the peripheral speed of the winding bobbin 22 (or the package 30) becomes larger. Accordingly, since the peripheral speed difference between the winding bobbin 22 (or the package 30) and the contact roller 29 can be made smaller, the slip of the yarn 20 printed on the contact roller 29 can be suppressed, and accurate traverse can be executed.
The arm type traverse device 27 is structured such that the print length tends to become longer at the traverse stroke ends during the traverse of the yarn 20. If the print length becomes long, the yarn 20 printed on the contact roller 29 tends to be affected by the peripheral speed difference between the contact roller 29 and the package 30. As a result, the yarn 20 printed on the contact roller 29 tends to slip on the contact roller 29. That is, since the print length becomes longer at the traverse stroke ends, the arm type traverse device 27 has a problem that the slip tends to be generated.
In this regard, by winding the yarn 20 using the tapered contact roller 29 as in the present embodiment, the peripheral speed difference generated between the package 30 and the contact roller 29 can be made small in the larger diameter end and the smaller diameter end of the winding bobbin 22. In FIG. 1, the larger diameter end of the winding bobbin 22 is arranged in the right end of the traverse stroke, and the smaller diameter end of the winding bobbin 22 is arranged in the left end of the traverse stroke. Accordingly, the slip of the yarn 20 at both the right and left ends of the traverse stroke can be reduced by using the contact roller 29 according to the present embodiment.
As described above, the tapered contact roller 29 can reduce the defect of the arm type traverse device 27, that is, the slip of the yarn 20 that tends to be generated at the traverse stroke ends. Accordingly, it is particularly preferable to combine the arm type traverse device 27 and the tapered contact roller 29, as the automatic winder according to the present embodiment.
In place of the structure in which the contact roller 29 is rotated by driving and rotating the winding bobbin 22 (or the package 30) as described above, the winding bobbin 22 (or the package 30) may be rotated by driving and rotating the contact roller 29. However, when having the winding bobbin 22 (or the package 30) rotated, in order to stably rotate the winding bobbin 22 (or the package 30) , a sufficient amount of contact area needs to be obtained between the contact roller 29 and the winding bobbin 22 (or the package 30). Therefore, in this case, the diameter of the contact roller 29 is required to be made large to some extent. If the contact roller 29 is enlarged as described above, the print length becomes longer. Since the traverse guide 11 cannot be provided close to the package 30 if the diameter of the contact roller 29 is large, a free length may become longer.
As described above, if the print length is too long, the yarn 20 tends to slip on the contact roller 29. If the free length is too long, a behavior of the yarn 20 becomes unstable, and reproducibility of the locus of the yarn 20 wound into the package 30 becomes low (that is, a delay is generated in the locus) . In this regard, in the present embodiment, the diameter of the contact roller 29 can be formed small by directly driving and rotating the winding bobbin 22 as described above. As a result, since the print length and the free length can be shortened, the high quality package 30 can be formed by reducing the slip of the yarn 20 on the contact roller 29.
Next, a description will be made in detail of a shape of the contact roller 29.
As described above, from the viewpoint that the yarn 20 is accurately traversed with respect to the surface of the package 30, even within a region located closer to the smaller diameter side than the uniform speed point, the peripheral speed of the contact roller 29 is preferable to coincide with the peripheral speed of the winding bobbin 22 (or the package 30). Similarly, even within a region located closer to the larger diameter side than the uniform speed point, the peripheral speed of the contact roller 29 is preferable to coincide with the peripheral speed of the winding bobbin 22 (or the package 30). Accordingly, if the shape of the contact roller 29 is formed at the same larger and smaller diameter ratio as the winding bobbin 22, the difference in the peripheral speed can be prevented from being generated between the winding bobbin 22 and the contact roller 29 in both of the larger diameter side and the smaller diameter side of the winding bobbin 22. The "larger and smaller diameter ratio" refers to a ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end.
Meanwhile, in the conical package 30, the difference between the peripheral speed in the smaller diameter side and the peripheral speed in the larger diameter side of the package 30 becomes smaller accompanying an increase in the diameter of the package 30. This is because since the speed at which the thickness of the yarn layer increases is almost the same at the smaller diameter side and the larger diameter side when the yarn 20 is wound around the winding bobbin 22 to form the yarn layer, the larger and smaller diameter ratio of the package 30 becomes gradually smaller. Therefore, if the shape of the contact roller 29 is formed at the same larger and smaller diameter ratio as that of the winding bobbin 22, the peripheral speed of the contact roller 29 can be coincided with the peripheral speed of the winding bobbin 22 at the start of winding the package 30. However, as the diameter of the package 30 increases, the peripheral speed difference is enlarged at the larger diameter side and the smaller diameter side than at the uniform speed point.
Accordingly, in the present embodiment, the contact roller 29 is formed such that the larger and smaller diameter ratio (d₂/d₁ in FIG. 3) of the contact roller 29 becomes smaller than the larger and smaller diameter ratio (D₂/D₁ in FIG. 3) of the winding bobbin 22. Therefore, the larger and smaller diameter ratio associated with the increase in the diameter of the package 30 can be obtained, as compared to the structure in which the larger and smaller diameter ratio of the contact roller 29 is coincided with the larger and smaller diameter ratio of the winding bobbin 22. In other words, as compared to the structure in which the larger and smaller diameter ratios of the winding bobbin 22 and the contact roller 29 are coincided, the peripheral speed difference between the contact roller 29 and the package 30 generated closer to the larger diameter side and the smaller diameter side than the uniform speed point can be made small at the increased diameter of the package 30.
In the automatic winder, winding bobbins having various larger and smaller diameter ratios are used depending on an intended purpose of the package, the yarn type or the like. Accordingly, it is preferable if one contact roller can be used for a plurality of types of winding bobbins. In this regard, according to the structure described above, the larger and smaller diameter ratio of the contact roller 29 does not need to coincide with the larger and smaller diameter ratio of the winding bobbin 22. Therefore, one contact roller 29 can be used for winding bobbins 22 having various larger and smaller diameter ratios.
Regarding this point, the inventors have carried out experiments of winding the yarn by using the contact rollers 29 having various larger and smaller diameter ratios for determining a shape of a general-purpose contact roller 29 which can be applied to conical bobbins of various shapes. Results are shown in a table in FIG. 4. FIG. 4 illustrates the results of visual observation obtained by evaluating the end surface of the package formed by using the contact roller 29. In FIG. 4, "1" denotes the best, "3" denotes average, and "5" denotes the worst. More specifically, in the package having the evaluation "1", stitching did not generate or hardly generated in both of the larger diameter side and the smaller diameter side, and the end surface of the package was clean. In such a package, the yarn cut or the like is hardly generated, for example, when unwinding the yarn from the package in a subsequent processing. On the other hand, in the package having the evaluation "5", a depression was generated in an inner layer of the package or the stitching was generated in the larger diameter side, and a wrinkle was generated in the smaller diameter side, and the end surface of the package was not clean. In such a package, the yarn cut or the like tends to be generated, for example, when unwinding the yarn from the package in a subsequent processing.
A left end of each row in FIG. 4 illustrates a diameter of the used winding bobbin, and a ratio of diameter (D₁ : D₂) between the smaller diameter end and the larger diameter end of the winding bobbin. An upper end of each line in FIG. 4 illustrates a ratio of diameter (d₁ : d₂) between the smaller diameter end and the larger diameter end of the used contact roller.
As described above, when the winding bobbin is conical, quality of the package is deteriorated if the package is wound using the cylindrical contact roller. Therefore, the contact roller is preferably formed based on a certain degree of larger and smaller diameter ratio. In this regard, as illustrated in the table in FIG. 4, when the conical winding bobbin is used, an improvement in the package quality as compared to the cylindrical contact roller was recognized by using the contact roller in which the larger and smaller diameter ratio (=d₂/d₁₎ is at least 1.1. Accordingly, the larger and smaller diameter ratio of the contact roller 29 is preferably set to be at least 1.1.
On the other hand, from the table in FIG. 4, the evaluation becomes "4" if the larger and smaller diameter ratio (=d₂/d₁) of the winding bobbin 22 becomes equal to or greater than the larger and smaller diameter ratio (= D₂/D₁) of the contact roller. In other words, if the larger and smaller diameter ratio of the contact roller 29 is made too large, the quality of the package 30 deteriorates. Accordingly, the larger and smaller diameter ratio of the contact roller 29 is preferably set to be less than the larger and smaller diameter ratio of the winding bobbin 22. The larger and smaller diameter ratio of the generally used conical winding bobbin is at most 1.8. Therefore, the larger and smaller diameter ratio of the contact roller is preferably set to be less than 1.8.
The table in FIG. 4 illustrates with a two-dot chain line a range of the contact roller 29 which can be determined to be used in common for three types of winding bobbins having general taper angles 3° 30' , 4° 20' and 5° 57' (the ratios of diameter between the smaller diameter end and the larger diameter end are respectively 1 : 1.6, 1 : 1.6 and 1 : 1.8). In other words, the contact roller 29 in which the larger and smaller diameter ratio is in the range of at least 1.1 and at most 1.5 can be used in common for the plurality of types of winding bobbins. Accordingly, the contact roller 29 in which the larger and smaller diameter ratio is in this range can be generally used for winding bobbins of various shapes. Particularly, the contact roller in which the larger and smaller diameter ratio is in the range from 1.3 to 1.5 is preferable because the evaluation equal to or higher than "3" (average) is obtained in all of three types of winding bobbins. Further, the contact roller having the larger and smaller diameter ratio 1.4 which is an intermediate value of the range from 1.3 to 1.5 is particularly preferable.
The width (the length in the direction of the rotational axis) of the contact roller 29 is not particularly limited, however, is required to be made at least longer than the width at which the yarn 20 is traversed with respect to the surface of the package 30. In the present embodiment, the width of the contact roller 29 is set to be substantially the same as the width of the winding bobbin 22. Although the diameter of the contact roller 29 is not particularly limited, inertia becomes too large if the diameter is made too large, and it is not preferable in view of the manufacturing cost. In the present embodiment, at least the diameter of the larger diameter end of the contact roller 29 is smaller than the diameter of the larger diameter end of the winding bobbin 22.
As described above, the automatic winder according to the present embodiment includes the cradle 23, the contact roller 29 and the traverse device 27. The cradle 23 rotatably supports the winding bobbin 22 around which the package 30 of the yarn 20 is wound. The contact roller 29 rotates while making contact with the package 30. The traverse device 27 is provided independently from the contact roller 29, and traverses the yarn 20 with respect to the surface of the package 30. The contact roller 29 is formed as the taper shape. The larger and smaller diameter ratio of the contact roller 29 is smaller than the larger and smaller diameter ratio of the winding bobbin 22.
By forming the contact roller 29 as the taper shape as described above, the peripheral speed difference generated between the contact roller 29 and the cone winding package 30 can be made smaller as compared to the structure in which the contact roller is formed cylindrical. Accordingly, the stitching or the like in the larger diameter side which tends to be generated when winding the cone winding package 30 can be prevented, thereby forming the high quality package 30. Further, the larger and smaller diameter ratio of the cone winding package 30 becomes smaller accompanying an increase in the diameter of the package 30. Accordingly, as described above, by forming the larger and smaller diameter ratio of the contact roller 29 to be smaller than the larger and smaller diameter ratio of the winding bobbin 22, the peripheral speed difference generated between the contact roller 29 and the cone winding package 30 can be prevented from becoming excessively large even if the diameter of the package 30 increases. Further, in the conventional structure (Japanese Unexamined Utility Model Publication No. 3-49259 ) in which the contact roller is formed in conformity to the shape of the bobbin, a different contact roller needs to be prepared per bobbin having a different shape. However, with the above structure, the contact roller 29 can be used for a plurality of types of bobbins as long as the ratio of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end of the bobbin is larger than that of the contact roller.
In the automatic winder according to the present embodiment, the cradle 23 has the smaller diameter side supporting arm 23a and the larger diameter side supporting arm 23b, and the cradle 23 can support the conical winding bobbin 22. The smaller diameter end of the contact roller 29 is arranged with respect to the smaller diameter side supporting arm 23a. The larger diameter end of the contact roller 29 is arranged with respect to the larger diameter side supporting arm 23b. Accordingly, the peripheral speed difference between the contact roller 29 and the winding bobbin 22 (or the package 30) can be made small.
In the automatic winder according to the present embodiment, the larger and smaller diameter ratio of the contact roller 29 is at least 1.1 and less than 1.8. By making the larger and smaller diameter ratio to be at least 1.1, the contact roller 29 having a taper to some degree can be formed. The larger and smaller diameter ratio of the generally used conical winding bobbin is at most 1.8. Therefore, by making the larger and smaller diameter ratio of the contact roller 29 to be less than 1.8, the larger and smaller diameter ratio of the contact roller 29 can be made smaller than the larger and smaller diameter ratio of the general conical bobbin. As a result, even when winding any type of conical bobbin among the generally existing plural types of conical bobbins, a high quality package can be wound by the yarn winding machine while maintaining the peripheral speed difference generated between the contact roller and the cone winding package to be small.
In the automatic winder according to the present embodiment, the cradle 23 can support the bobbin having the larger and smaller diameter ratio of 1.6 and the winding bobbin having the larger and smaller diameter ratio of 1.8. The winding bobbins having the larger and smaller diameter ratios 1.6 and 1.8 are commonly used. Therefore, by forming the automatic winder according to the present embodiment to be capable of supporting such bobbins, the automatic winder can wind the yarn around winding bobbins of many types.
The automatic winder according to the present embodiment is provided with the package driving motor 41 which directly drives and rotates the winding bobbin 22. When passively rotating the winding bobbin 22 (or the package 30) by driving and rotating the contact roller 29, the diameter of the contact roller 29 needs to be made large to some degree for reliably driving the winding bobbin 22 (or the package 30). In this regard, with the above structure, the size of the contact roller 29 does not need to be made large, and the contact roller 29 can be formed compact.
In the automatic winder according to the present embodiment, the traverse device 27 includes the traverse arm 28, and the traverse guide 11 which is arranged at the tip end of the traverse arm 28. By engaging the yarn 20 with the traverse guide 11 and rotationally driving the traverse arm 28 with its base end as the center, the traverse device 27 traverses the yarn 20 with respect to the surface of the package 30 by reciprocating the traverse guide 11.
In other words, since the traverse device with the traverse arm is structured such that the print length tends to be longer at both ends of the traverse stroke during the traverse, the yarn 20 printed on the contact roller 29 particularly tends to slip. Accordingly, the effect of improving the quality of the package 30 can be particularly significantly obtained by adapting the structure of the present invention in the automatic winder provided with the traverse device having the traverse arm 28 and reducing the slip of the yarn 20.
The automatic winder according to the present embodiment includes the traverse arm driving motor 45 which rotationally drives the traverse arm 28. When viewed from the direction of the straight line connecting both ends of the traverse stroke, the driving shaft center 45a of the traverse arm driving motor 45 and the extended line of the yarn path of the yarn 20 wound into the package 30 intersect while forming an acute angle.
In the automatic winder according to the present embodiment, when viewed from the direction of the straight line connecting both ends of the traverse stroke, an imaginary line passing through the base end of the traverse arm 28 and the traverse guide 11 is substantially perpendicular to the yarn path.
Accordingly, bending of the yarn 20 by the traverse guide 11 particularly the traverse stroke ends can be reduced. As a result, the load applied to the yarn 20 wound into the package 30 can be reduced, and the quality of the package 30 can be further improved.
Next, a description will be made of a modified example of the above embodiment. In the following description, as to components which are the same or similar to the above embodiment, the same reference numerals are denoted in the drawings and the description thereof will be omitted.
As illustrated in FIG. 5, the automatic winder according to this modified example includes a contact roller driving motor 51 for driving the contact roller 29 in place of the package driving motor 41 for driving the winding bobbin 22 (or the package 30). In the automatic winder having this structure, the winding bobbin 22 (or the package 30) is rotated by driving and rotating the contact roller 29.
Even in the automatic winder according to this structure, when winding the yarn 20 around the conical winding bobbin, the peripheral speed difference between the contact roller 29 and the winding bobbin 22 (or the package 30) can be made small by using the tapered contact roller 29 in the same manner as the above embodiment. Accordingly, the slip of the yarn 20 printed on the contact roller 29 can be suppressed.
In the case of the structure in which the contact roller 29 is driven and rotated, as described above, the diameter of the contact roller 29 needs to be formed larger for stabilizing the rotation of the winding bobbin 22 (or the package 30) as compared to the structure in which the winding bobbin 22 is directly driven and rotated. However, if the diameter of the contact roller 29 is formed large as described above, there is a problem that the print length becomes longer and the slip of the yarn 20 increases. Therefore, in view of reducing the slip of the yarn 20 and improving the quality of the package 30, the structure for directly driving the winding bobbin 22 (or the package 30) as in the above embodiment is preferable.
The description has been made of the preferred embodiment (and the modified example) according to the present invention, however, the above structure may be changed, for example, as follows.
As illustrated in FIG. 4, the tapered contact roller in which the larger and smaller diameter ratio is less than 1.8 can form a cheese winding package in which the evaluation is equal to or higher than "3" (average) even if the contact roller is used for a cylindrical winding bobbin. In other words, the contact roller 29 according to the present embodiment can also be used for the cylindrical winding bobbin.
In the traverse device 27 according to the above embodiment, when viewed from the direction of the straight line connecting both ends of the traverse stroke, the driving shaft center 45a of the traverse arm driving motor 45 is arranged such that the extended line of the driving shaft center 45a and the yarn path of the yarn 20 form an acute angle. In this regard, when viewed from the direction of the straight line connecting both ends of the traverse stroke, the driving shaft center 45a and the yarn 20 located upstream of the yarn guiding member 52 may be parallel to one another. The point is that the traverse guide 11 can be reciprocated within the plane which is substantially parallel to the installation surface of the winder unit 10.
As a matter of fact, the traverse device 27 is not limited to the structure in which the traverse guide 11 is reciprocated within the substantially horizontal surface as in the above embodiment, but the conventional traverse device which reciprocates the traverse guide within the substantially vertical surface as in, for example, Japanese Unexamined Patent Publication No. 2006-298499 , may be used as the traverse device 27.
In place of the arm type traverse device as described above, the traverse device 27 may be formed by a belt type traverse device which reciprocates the traverse guide right and left by a belt, a rotary type traverse device using a rotary blade, a rod type traverse device which reciprocates a rod to which the traverse guide is attached, and the like.
The shape of the traverse guide 11 according to the above embodiment may be appropriately changed according to circumstances. For example, the portion of the traverse guide engaging the yarn may be formed as U-shape in which a tip end is opened. Further, for example, the traverse may be carried out by nipping the yarn with two rod-like members.
The present invention is not limited to the automatic winder, but can be applied to other yarn winding machines such as a rewinding machine, a spinning machine (for example, a pneumatic spinning machine, and an open-end spinning machine) and the like.

Claims

A yarn winding machine comprising:
a bobbin supporting section (23) adapted to rotatably support a bobbin around which a yarn is wound into a package;

a contact roller (29) that rotates while making contact with the package;

a traverse device (27) that is provided independently from the contact roller (29) and traverses the yarn with respect to the surface of the package;

wherein the contact roller (27) is formed in a taper shape, and a ratio (d2:d1) of a diameter of a larger diameter end with respect to a diameter of a smaller diameter end of the contact roller (27) is smaller than a ratio (D2:D1) of a diameter of a larger diameter end with respect to a diameter of a smaller diameter end of the bobbin.
The yarn winding machine according to claim 1, wherein the bobbin supporting section (23) has a smaller diameter side supporting section (23a) and a larger diameter side supporting section (23b) to support a conical bobbin, and
the smaller diameter end of the contact roller (29) is arranged with respect to the smaller diameter side supporting section (23a), and the larger diameter end of the contact roller (29) is arranged with respect to the larger diameter side supporting section (23b).
The yarn winding machine according to claim 1 or claim 2, wherein the ratio (d2:d1) of the diameter of the larger diameter end with respect to the diameter of the smaller diameter end of the contact roller (27) is at least 1.1 and less than 1.8.
The yarn winding machine according to claim 3, wherein the bobbin supporting section (23) can support at least a bobbin of which the ratio (D2:D1) of the diameter of the larger diameter end with respect to the diameter of the larger diameter end is 1.6.
The yarn winding machine according to claim 3, wherein the bobbin supporting section (23) can support at least a bobbin of which the ratio (D2:D1) of the diameter of the larger diameter end with respect to the diameter of the larger diameter end is 1.8.
The yarn winding machine according to any one of claim 1 through claim 5, further comprising a package driving section (41) adapted to directly drive and rotate the bobbin.
The yarn winding machine according to claim 1 through claim 6, wherein the traverse device (27) includes a traverse arm (28) and a traverse guide (11) arranged at a tip end of the traverse arm (28), and traverses the yarn with respect to the surface of the package by reciprocating the traverse guide (11) by rotationally driving the traverse arm (28) with its base end as a center under a state in which the yarn is engaged in the traverse guide (11).
The yarn winding machine according to claim 7, further comprising a traverse driving section (45) adapted to drive and rotate the traverse arm (28),
wherein when viewed from a direction of a straight line connecting both ends of a traverse stroke, a driving shaft center of the traverse driving section (45) and an extended line of a yarn path of the yarn wound into the package intersect while forming an acute angle or are parallel to one another.
The yarn winding machine according to claim 8, wherein when viewed from the direction of the straight line connecting both ends of the traverse stroke, an imaginary line passing through the base end of the traverse arm (28) and the traverse guide (11) is substantially perpendicular to the yarn path.