Fiber-spreading device and fiber-spreading method

Abstract

To stably obtain a fiber bundle that is widely opened.SOLUTION: An opening device comprises: a delivery machine 20 to continuously deliver a long fiber bundle 105; a pair of feed rolls 60 to convey the fiber bundle 105 delivered by the delivery machine 20 to a downstream side; a plurality of opening bars 30 disposed between the delivery machine 20 and the feed roll 60 on a conveying passage 110; and a pair of accelerating relaxation rolls 40 disposed between the opening bar 30 and the feed roll 60 on the conveying passage 110 and rotating at increased speed within a range at which the peripheral velocity thereof with respect to the peripheral velocity of the feed roll 60 is 650% or less and allowing outer peripheral surfaces 44 to come in contact with the fiber bundle 105. The pair of accelerating relaxation rolls 40 have: a first accelerating relaxation roll 41 disposed on a downstream side of the opening bar 30; and a second accelerating relaxation roll 42 disposed between the first accelerating relaxation roll 41 and the feed roll 60 on the conveying passage 110 and coming in contact with a surface different from a surface with which the first accelerating relaxation roll 41 comes in contact in the fiber bundle 105.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fiber-spreading device and a fiber-spreading method, and more particularly to a fiber-spreading device and a fiber-spreading method for spreading fiber bundles of carbon fibers. [Background technology]

[0002] Many proposals have been made so far regarding methods for spreading carbon fibers. For example, Patent Document 1 discloses a method for spreading carbon fibers using a vibrating bar.

[0003] Patent Document 2 describes a fiber-spreading device that includes a fiber-spreading promoting member having corners extending in a direction perpendicular to the feeding direction of the fiber bundle, and feeds the fiber bundle while pressing the fiber bundle against the corners of the fiber-spreading promoting member, thereby causing a shift in the width direction of the fibers constituting the fiber bundle and spreading the fiber bundle. Patent Document 2 also describes that the fiber bundle is further spread by blowing air from an air supplier to the fiber bundle.

[0004] Patent Document 3 describes a fiber-spreading device that softens oil agents and sizing agents (sizing agents) and spreads carbon fiber bundles by bringing carbon fiber bundles into contact with the surface of a heated fiber bundle contacting means and passing the carbon fiber bundles through the fiber bundle contacting means while bending the carbon fiber bundles. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-163196 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-129633 [Patent Document 3] Japanese Patent Application Publication No. 2017-203235 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when carbon fiber bundles are spread using a vibrating bar, fluff may occur in the fiber bundle, and the fluff generated in the fiber bundle may cause the fiber bundle to wind around a roll in a process subsequent to the spreading process, which may result in a decrease in yield or a difference in the supply amount for each fiber bundle. Furthermore, when air is used to spread the fiber to a wide spread width, the fibers are scattered by the air, which may require the preparation of a dust collector or enclosure, which may result in high costs. For this reason, it has been very difficult to stably spread carbon fiber bundles to a wide width.

[0007] The present invention has been made in view of the above, and has an object to provide a fiber spreading device and a fiber spreading method that can stably obtain a fiber bundle that is spread to a wide width. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, a fiber-spreading device according to the present invention includes a payout machine that continuously pays out a long fiber bundle obtained by bundling carbon fibers with a sizing agent, a pair of feed rolls that are each formed in a cylindrical shape and rotate in opposite directions while sandwiching the fiber bundle paid out from the payout machine between them, thereby transporting the fiber bundle to the downstream side of a transport path of the fiber bundle, and a plurality of rod-shaped feed rolls that are arranged between the payout machine and the feed rolls on the transport path and are arranged at positions where they alternately come into contact with different surfaces of the fiber bundle as they move from the upstream side to the downstream side on the transport path. and a pair of speed-increasing relaxation rolls each formed in a cylindrical shape and arranged between the spreading bars and the feed roll in the transport path, rotating at an increased peripheral speed within a range of 650% or less of the peripheral speed of the feed roll, the outer circumferential surfaces of which contact the fiber bundle, wherein the pair of speed-increasing relaxation rolls includes a first speed-increasing relaxation roll arranged downstream of the spreading bars in the transport path, and a second speed-increasing relaxation roll arranged between the first speed-increasing relaxation roll and the feed roll in the transport path, which contacts a surface of the fiber bundle different from a surface of the fiber bundle that contacts the first speed-increasing relaxation roll.

[0009] In order to solve the above-mentioned problems and achieve the object, the fiber-spreading method according to the present invention comprises continuously unwinding a long fiber bundle obtained by bundling carbon fibers with a sizing agent from a unwinding machine, sandwiching the fiber bundle unwound from the unwinding machine between a pair of feed rolls rotating in opposite directions and transporting the fiber bundle downstream in a transport path of the fiber bundle, and alternately bringing different surfaces of the fiber bundle into contact with the plurality of rod-shaped fiber-spreading bars arranged between the unwinding machine and the feed rolls in the transport path from the upstream side to the downstream side in the transport path, thereby spreading the fiber bundle. the fiber bundle is brought into contact with outer peripheral surfaces of a pair of speed-increasing relaxation rolls, the pair of speed-increasing relaxation rolls being arranged between the spreading bar and the feed rolls in the conveying path, the pair of speed-increasing relaxation rolls being cylindrical and rotating at a peripheral speed that is 650% or less of the peripheral speed of the feed rolls, the pair of speed-increasing relaxation rolls being a first speed-increasing relaxation roll arranged downstream of the spreading bar in the conveying path, and a second speed-increasing relaxation roll arranged between the first speed-increasing relaxation roll and the feed rolls in the conveying path, and the fiber bundle is spread by bringing different surfaces of the fiber bundle into contact with the first speed-increasing relaxation roll and the second speed-increasing relaxation roll. [Effects of the Invention]

[0010] The fiber-spreading device and fiber-spreading method according to the present invention have the effect of stably obtaining a fiber bundle that is spread to a wide width. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a fiber-spreading device according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram showing a modified example of the fiber-spreading device according to the embodiment, in which the first speed-increasing / relaxing roll is disposed below the second speed-increasing / relaxing roll. [Figure 3] FIG. 3 is a schematic diagram showing a modified example of the fiber-spreading device according to the embodiment, in which a pair of feed rolls are arranged side by side in the second direction Y. In FIG. [Figure 4]FIG. 4 is a schematic diagram showing a modified example of the fiber-spreading device according to the embodiment, in which a pair of feed rolls are arranged side by side in the second direction Y. In FIG. [Figure 5] FIG. 5 is a schematic diagram showing a modified example of the fiber-spreading device according to the embodiment, in which a pair of speed-up relaxation rolls are arranged side by side in the second direction Y. In FIG. [Figure 6] FIG. 6 is a schematic diagram showing a modified example of the fiber-spreading device according to the embodiment, in which a pair of speed-up relaxation rolls are arranged side by side in the second direction Y. [Figure 7] FIG. 7 is a schematic diagram showing a modified example of the fiber-spreading device according to the embodiment, in which a pair of speed-up / relaxation rolls and a pair of feed rolls are arranged side by side in the second direction Y. In FIG. [Figure 8] FIG. 8 is a schematic diagram showing a modified example of the fiber-spreading device according to the embodiment, in which a pair of speed-up / relaxation rolls and a pair of feed rolls are arranged side by side in the second direction Y. In FIG. [Figure 9] FIG. 9 is a schematic diagram showing the device configuration of the fiber-spreading device used in the evaluation test. [Figure 10] FIG. 10 is a chart showing the results of the evaluation test. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of a fiber-spreading device and a fiber-spreading method according to the present disclosure will be described in detail with reference to the drawings. Note that the present invention is not limited to these embodiments. Furthermore, the components in the following embodiments include those that are replaceable and easily conceivable by a person skilled in the art, or those that are substantially the same.

[0013] [Embodiment] FIG. 1 is a schematic diagram of a fiber-spreading device 10 according to an embodiment. The following description will use a first direction X, a second direction Y, and a third direction Z, which are perpendicular to one another. The first direction X is the direction in which the central rotation axes of a reel-out machine 20, an acceleration / relaxation roll 40, a guide roll 50, and a feed roll 60, which will be described later, extend. The first direction X is the direction that extends horizontally when the fiber-spreading device 10 is installed in an arbitrary installation location and used in a normal usage mode. The second direction Y is a direction that is perpendicular to the first direction X and is horizontally perpendicular to the first direction X when the fiber-spreading device 10 is installed in an arbitrary installation location and used in a normal usage mode. The third direction Z is a direction that is perpendicular to both the first direction X and the second direction Y. Therefore, the third direction Z is the vertical direction or the direction of gravity when the fiber-spreading device 10 is installed in an arbitrary installation location and used in a normal usage mode. In the following description, the upper side in the direction of gravity when the fiber-spreading device 10 is used in a normal manner will be referred to as the upper side of the fiber-spreading device 10, and the lower side in the direction of gravity will be referred to as the lower side of the fiber-spreading device 10.

[0014] <Opening device 10> The spreader 10 according to this embodiment is a device that can spread a long fiber bundle 105 in which carbon fibers are bundled with a sizing agent. That is, the fiber bundle 105 is a bundle of carbon fibers in which carbon fibers are bundled with a sizing agent made of a resin material or the like, and the spreader 10 is a device that spreads the fiber bundle 105 thus configured into a thin, wide shape.

[0015] The fiber-spreading device 10 includes a reeling machine 20, a fiber-spreading bar 30, an increasing-speed relaxation roll 40, a guide roll 50, and a feed roll 60. The reeling machine 20, the fiber-spreading bar 30, the increasing-speed relaxation roll 40, the guide roll 50, and the feed roll 60 are all disposed at the same position in the first direction X, and are respectively disposed on a transport path 110 of the fiber bundle 105 to be spread by the fiber-spreading device 10. In other words, the transport path 110 of the fiber bundle 105 is formed as a continuous path for transporting the fiber bundle 105 by winding the long fiber bundle 105 around or bringing it into contact with the reeling machine 20, the fiber-spreading bar 30, the increasing-speed relaxation roll 40, the guide roll 50, and the feed roll 60.

[0016] Furthermore, in this embodiment, the fiber bundle 105 unwound from the unwinding machine 20 is transported along a transport path 110 of the fiber bundle 105 from the side where the unwinding machine 20 is located to the side where the feed roll 60 is located. Therefore, in the spread device 10 according to this embodiment, the side of the transport path 110 of the fiber bundle 105 where the unwinding machine 20 is located is the upstream side, and the side where the feed roll 60 is located is the downstream side, and the fiber bundle 105 is transported.

[0017] <Feeder 20> The unwinder 20 is formed in a cylindrical shape, and a roving 100, on which a fiber bundle 105 is wound into a cylindrical shape, is attached to the outer circumferential surface of the cylinder. The unwinder 20 is rotatable around the axis of the cylinder as a central axis of rotation, and is disposed such that the direction in which the central axis of rotation extends is the first direction X. By rotating around the central axis of rotation, the unwinder 20 can continuously unwind the fiber bundle 105 from the roving 100 attached to the unwinder 20.

[0018] Furthermore, a plurality of rovings 100 can be attached to the unwinding machine 20 so as to be aligned in the first direction X. Fig. 1 is a schematic diagram showing a position where one roving 100 attached to the unwinding machine 20 is arranged in the first direction X, but in the spreading device 10, a plurality of fiber bundles 105 are arranged so as to be aligned in the first direction X, and a plurality of conveying paths 110 as shown in Fig. 1 are formed in the first direction X.

[0019] <Feed Roll 60> A pair of feed rolls 60 are provided, and are arranged at positions in at least one of the second direction Y and the third direction Z that are different from the unwinding machine 20. In this embodiment, as shown in FIG. 1 , the feed rolls 60 are arranged at the same position as the unwinding machine 20 in the third direction Z, and at a position different from the unwinding machine 20 in the second direction Y.

[0020] The pair of feed rolls 60 are each formed in a cylindrical shape, and are arranged such that the direction in which a rotation central axis 67 extends corresponds to the first direction X, and each is rotatable about the rotation central axis 67. The cylindrical feed rolls 60 preferably have a diameter of approximately 50 mm to 300 mm. The pair of feed rolls 60 rotate in opposite directions while sandwiching the fiber bundle 105 unwound from the unwinding machine 20 between the pair of feed rolls 60, thereby transporting the fiber bundle 105 downstream of the spread device 10 in a transport path 110 for the fiber bundle 105.

[0021] More specifically, the pair of feed rolls 60 includes a first feed roll 61 and a second feed roll 62. The first feed roll 61 has an outer circumferential surface 64 made of a resilient rubber material, while the second feed roll 62 has an outer circumferential surface 64 with a matte finish. An air cylinder 66 is connected to the first feed roll 61, and the first feed roll 61 is pressed against the second feed roll 62 by the force applied by the air cylinder 66. A drive motor 65 is connected to the second feed roll 62, and the second feed roll 62 can rotate about a rotation center shaft 67 by the driving force transmitted from the drive motor 65.

[0022] It is preferable that the hardness of the rubber member forming the outer peripheral surface 64 of the first feed roll 61 be set appropriately depending on the magnitude of the force when pressing the first feed roll 61 against the second feed roll 62, the conveying speed of the fiber bundle 105, etc. Furthermore, the drive device connected to the first feed roll 61 and pressing the first feed roll 61 against the second feed roll 62 may be something other than the air cylinder 66. For example, a hydraulic cylinder may be connected to the first feed roll 61, and the first feed roll 61 may be configured to be pressed against the second feed roll 62 by the force applied by the hydraulic cylinder.

[0023] The outer circumferential surface 64 of the first feed roll 61 is pressed against the outer circumferential surface 64 of the second feed roll 62 by the force of the air cylinder 66, and therefore, when the second feed roll 62 rotates by the driving force transmitted from the drive motor 65, the first feed roll 61 also rotates. In other words, the first feed roll 61 rotates because the portion of the outer circumferential surface 64 of the first feed roll 61 that contacts the second feed roll 62 moves in the same direction as the portion of the outer circumferential surface 64 of the second feed roll 62 that contacts the first feed roll 61. As a result, the first feed roll 61 rotates in a direction opposite to the rotation direction of the second feed roll 62 when viewed in a direction along the central axis of rotation 67.

[0024] The rotation direction of the first feed roll 61 and the second feed roll 62 is such that the opposing portions of the outer surface 64 of the first feed roll 61 and the outer surface 64 of the second feed roll 62 move from the upstream side of the conveying path 110 of the fiber bundle 105 toward the downstream side of the fiber-spreading device 10.

[0025] The pair of feed rolls 60 are rotated by the driving force transmitted from the drive motor 65, and thus the fiber bundle 105 unwound from the unwinding machine 20 can be conveyed downstream in a conveyance path 110 for the fiber bundle 105 by rotating while sandwiched between the first feed roll 61 and the second feed roll 62. That is, the outer circumferential surface 64 of the first feed roll 61 is made of an elastic rubber member, and therefore the outer circumferential surface 64 of the first feed roll 61 elastically deforms at the portion where the fiber bundle 105 is positioned between the first feed roll 61 and the second feed roll 62, thereby enabling the fiber bundle 105 to be sandwiched between the first feed roll 61 and the second feed roll 62. As a result, the first feed roll 61 and the second feed roll 62 come into contact with the fiber bundle 105 at high pressure, and as the first feed roll 61 and the second feed roll 62 rotate, the fiber bundle 105 moves and is conveyed by the frictional force between the first feed roll 61 and the second feed roll 62.

[0026] Since the fiber bundle 105 is transported by the pair of feed rolls 60 in this manner, the transport speed of the fiber bundle 105 can be adjusted by adjusting the rotation speed of the feed rolls 60, which are rotated by the driving force transmitted from the drive motor 65.

[0027] The unwinder 20 that unwinds the fiber bundle 105 is able to unwind the fiber bundle 105 by rotating due to tension applied to the fiber bundle 105 from the pair of feed rolls 60. The unwinder 20 is provided as a so-called back tension roll that generates tension in the opposite direction to the traveling direction of the fiber bundle 105 unwound from the unwinder 20. Therefore, the unwinder 20 can apply a force to the fiber bundle 105 unwound from the unwinder 20 in the opposite direction to the direction in which the fiber bundle 105 advances along the conveyance path 110 due to the tension applied by the feed rolls 60. In other words, the unwinder 20 can apply a force to the fiber bundle 105 in the opposite direction to the direction in which the fiber bundle 105 is unwound from the unwinder 20.

[0028] <Opening bar 30> The plurality of fiber spreading bars 30 are formed in a rod shape and are arranged non-rotatably between the unwinder 20 and the feed rolls 60 on the conveying path 110. In this embodiment, the plurality of fiber spreading bars 30 are arranged between the unwinder 20 and the feed rolls 60 in the second direction Y. The plurality of fiber spreading bars 30 formed in a rod shape are arranged such that their extension directions are in the first direction X. The plurality of fiber spreading bars 30 are arranged in a so-called staggered pattern between the unwinder 20 and the feed rolls 60, from the side where the unwinder 20 is located toward the side where the feed rolls 60 are located, at positions between the unwinder 20 and the feed rolls 60. That is, the plurality of fiber spreading bars 30 are arranged in a staggered pattern from the upstream side toward the downstream side on the conveying path 110 of the fiber bundle 105.

[0029] Specifically, the multiple spreading bars 30 are arranged such that their positions in the third direction Z alternate between one direction and the other direction from the side where the unwinding machine 20 is located toward the side where the feed rolls 60 are located. That is, of the multiple spreading bars 30, the spreading bar 30 located closest to the unwinding machine 20 and the adjacent spreading bar 30 on the side where the feed rolls 60 are located are arranged so that their positions in the third direction Z are shifted in one direction relative to the spreading bar 30 located closest to the unwinding machine 20. Furthermore, the adjacent spreading bar 30 on the side where the feed rolls 60 are located is arranged so that its position in the third direction Z is shifted in the other direction relative to the spreading bar 30 located so that its positions are shifted in one direction in the third direction Z.

[0030] As a result, the multiple spreading bars 30 are arranged in a staggered pattern such that their positions in the third direction Z are alternately shifted from the upstream side to the downstream side on the conveying path 110 of the fiber bundle 105. In this embodiment, three spreading bars 30 are arranged, and the three spreading bars 30 are aligned in the second direction Y between the unwinder 20 and the feed roll 60, with the two spreading bars 30 at both ends being positioned close to each other in the third direction Z, and the central spreading bar 30 being positioned at a different position in the third direction Z from the two spreading bars 30 at both ends. That is, in this embodiment, of the three spreading bars 30 aligned in the second direction Y, the central spreading bar 30 is positioned above the two spreading bars 30 at both ends in the third direction Z.

[0031] The fiber bundle 105 is threaded around each of the plurality of fiber spreading bars 30 arranged in a staggered manner as described above. At this time, the fiber bundle 105 is threaded around the fiber spreading bars 30 from the outside in a direction in which the positions of the fiber spreading bars 30 are alternately shifted from the upstream side to the downstream side on the conveying path 110 of the fiber bundle 105. That is, when the plurality of fiber spreading bars 30 are arranged in a staggered manner by lining up in the second direction Y and alternately shifting their positions in the third direction Z, the fiber bundle 105 is threaded around the fiber spreading bars 30 from below for the fiber spreading bars 30 located relatively lower in the third direction Z, and the fiber bundle 105 is threaded around the fiber spreading bars 30 from above for the fiber spreading bars 30 located relatively higher in the third direction Z.

[0032] Therefore, the multiple spreading bars 30 alternately come into contact with different surfaces of the fiber bundle 105 as they move from the upstream side to the downstream side in the conveyance path 110 of the fiber bundle 105. In other words, the multiple spreading bars 30 are arranged at positions where they alternately come into contact with different surfaces of the fiber bundle 105 as they move from the upstream side to the downstream side in the conveyance path 110 of the fiber bundle 105.

[0033] The thus arranged fiber-spreading bars 30 have a matte surface. The fiber-spreading bars 30 are also heatable. For example, a heat medium such as gas or liquid heated by a heating device (not shown) can be passed through the interior of the fiber-spreading bar 30, and the fiber-spreading bar 30 can be heated by the transfer of temperature from the heat medium flowing inside the fiber-spreading bar 30. This allows the fiber-spreading bar 30 to heat the fiber bundles 105 that come into contact with the fiber-spreading bar 30.

[0034] <Accelerating Relaxation Roll 40> A pair of accelerating relaxation rolls 40 are arranged between the opening bar 30 and the feed roll 60 on the transport path 110 of the fiber bundle 105. Each of the pair of accelerating relaxation rolls 40 is formed in a cylindrical shape, and the outer circumferential surface 44 of each roll has a matte surface roughness. The pair of accelerating relaxation rolls 40 formed in a cylindrical shape are arranged so that the direction in which the rotation central axis 47 extends is the first direction X, and each roll is rotatable about the rotation central axis 47. The diameter of the accelerating relaxation roll 40 is larger than the diameter of the feed roll 60. The diameter of the accelerating relaxation roll 40 is desirably about 100 mm to 300 mm, for example.

[0035] Each of the pair of speed-increasing relaxation rolls 40 is capable of passing a heat medium, for example, a gas or liquid heated by a heating device (not shown), through the interior thereof, and can be heated by the heat transfer from the heat medium flowing inside the speed-increasing relaxation roll 40. In this way, the speed-increasing relaxation roll 40 can heat the fiber bundle 105 in contact with the speed-increasing relaxation roll 40.

[0036] The pair of speed-increasing relaxation rolls 40 includes a first speed-increasing relaxation roll 41 and a second speed-increasing relaxation roll 42, and the first speed-increasing relaxation roll 41 is disposed downstream of the opening bar 30 in the transport path 110 of the fiber bundle 105. The second speed-increasing relaxation roll 42 is disposed between the first speed-increasing relaxation roll 41 and the feed roll 60 in the transport path 110 of the fiber bundle 105.

[0037] The first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 are disposed with a predetermined gap between them. In this embodiment, the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 are positioned at approximately the same position in the second direction Y, and the second speed-up relaxation roll 42 is positioned below the first speed-up relaxation roll 41 in the third direction Z. Therefore, the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 are disposed with a predetermined gap between them in the third direction Z. The gap between the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 is preferably as small as possible, for example, approximately 1 mm to 50 mm. The gap between the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 is specifically the gap between the opposing outer circumferential surfaces 44 of the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42; in other words, it is a roll gap.

[0038] A drive motor 45 is connected to the pair of speed-up relaxation rolls 40, and each of the pair of speed-up relaxation rolls 40 can rotate about a central rotation axis 47 by a driving force transmitted from the drive motor 45. In this embodiment, the drive motor 45 is connected to the second speed-up relaxation roll 42, and the driving force generated by the drive motor 45 is transmitted to the second speed-up relaxation roll 42.

[0039] The first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 are connected via a power transmission mechanism (not shown) consisting of gears and the like, and the driving force transmitted from the drive motor 45 to the second speed-up relaxation roll 42 is transmitted via the power transmission mechanism to the first speed-up relaxation roll 41. As a result, the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 can each rotate about their own central rotation axis 47 by the driving force transmitted from the drive motor 45.

[0040] At this time, the power transmission mechanism that transmits the driving force between the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 is configured to rotate the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 in opposite directions to each other. As a result, the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 can rotate in opposite directions about their respective rotation central axes 47 by the driving force transmitted from the drive motor 45.

[0041] The fiber bundle 105 is wound around both the first increasing speed relaxation roll 41 and the second increasing speed relaxation roll 42 at a position downstream of the spreading bar 30 in the conveying path 110 of the fiber bundle 105, and the outer peripheral surfaces 44 of the first increasing speed relaxation roll 41 and the second increasing speed relaxation roll 42 come into contact with the fiber bundle 105. At this time, the fiber bundle 105 is wound around the first increasing speed relaxation roll 41 and the second increasing speed relaxation roll 42 so that different surfaces of the fiber bundle 105 come into contact with the first increasing speed relaxation roll 41 and the second increasing speed relaxation roll 42. In other words, when the fiber bundle 105 is wound around the first increasing speed relaxation roll 41 and the second increasing speed relaxation roll 42, the second increasing speed relaxation roll 42 comes into contact with a surface of the fiber bundle 105 that is different from the surface that comes into contact with the first increasing speed relaxation roll 41.

[0042] Specifically, when the speed-increasing relaxation roll 40 is viewed in a direction along the rotation center axis 47 of the speed-increasing relaxation roll 40, the fiber bundle 105 is wound around the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 in an S-shape or an inverted S-shape. That is, the portion of the fiber bundle 105 from the position where it is wound around the fiber spreading bar 30 toward the first speed-increasing relaxation roll 41 is wound around the first speed-increasing relaxation roll 41 from the side opposite to the side where the second speed-increasing relaxation roll 42 is located. The fiber bundle 105 further passes between the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 from the position where it is wound around the first speed-increasing relaxation roll 41, facing the side where the second speed-increasing relaxation roll 42 is located, and is wound around the second speed-increasing relaxation roll 42. As a result, the fiber bundle 105 is wound around the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 in an S-shape or an inverted S-shape.

[0043] At that time, when viewed from the portion of the fiber bundle 105 located between the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42, the portion of the fiber bundle 105 that is wound around the first speed-increasing relaxation roll 41 and the portion of the fiber bundle 105 that is wound around the second speed-increasing relaxation roll 42 are wound around such that different surfaces of the fiber bundle 105 come into contact with the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42. As a result, the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42, around which the fiber bundle 105 is wound, come into contact with different surfaces of the fiber bundle 105.

[0044] In this way, the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 come into contact with different surfaces of the fiber bundle 105, but the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 rotate in opposite directions when rotated by the driving force transmitted from the drive motor 45. Therefore, the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 rotate in a direction such that the portion of their outer circumferential surfaces 44 that is in contact with the fiber bundle 105 moves from the upstream side to the downstream side in the feeding direction of the fiber bundle 105.

[0045] At this time, the accelerating speed relaxation rolls 40 rotate at an increased speed within a range in which the peripheral speed is 650% or less of the peripheral speed of the feed rolls 60. In other words, the drive motor 45 that rotates the accelerating speed relaxation rolls 40 rotates the first accelerating speed relaxation roll 41 and the second accelerating speed relaxation roll 42 at an increased speed relative to the peripheral speed of the feed rolls 60 within a range in which the peripheral speed is 650% or less of the peripheral speed of the feed rolls 60. Specifically, each of the pair of accelerating speed relaxation rolls 40 rotates at an increased speed relative to the feed rolls 60 within a range in which the peripheral speed is 200% or more and 650% or less of the peripheral speed of the feed rolls 60.

[0046] The accelerating relaxation roll 40 is rotated at a peripheral speed faster than the peripheral speed of the feed roll 60, and when the rotation speed reaches a set rotation speed, the accelerating relaxation roll 40 is rotated at a constant speed while maintaining that speed, thereby making it possible to relax the tension in the fiber bundle 105 and spread the fiber bundle 105. The circumferential speed of the accelerating relaxation roll 40, which is rotated at a speed faster than the circumferential speed of the feed roll 60, can be changed separately from the circumferential speed of the feed roll 60. In other words, the rotation speed of the accelerating relaxation roll 40, which is rotated by a driving force transmitted from a drive motor 45, can be changed separately from the rotation speed of the feed roll 60.

[0047] The speed-up relaxation rolls 40 and the feed rolls 60 are each rotatable, but the rotation directions of a pair of speed-up relaxation rolls 40 and a pair of feed rolls 60 are opposite. More specifically, if the line connecting the speed-up relaxation rolls 40 and the line connecting the feed rolls 60 are taken as boundary lines 70, the rotation directions of the speed-up relaxation rolls 40 and the feed rolls 60 are opposite to each other when the rotation axes 47 and 67 of the feed rolls 60 are on the same side of the boundary lines 70.

[0048] In this case, boundary line 70 is a straight line connecting midpoint 68a of line 68 connecting the rotation central axes 67 of the pair of feed rolls 60 and midpoint 48a of line 48 connecting the rotation central axes 47 of the pair of speed-up and speed-down rolls 40. Feed roll 60 and speed-up and speed-down roll 40 have rotation central axes 47, 67 located on the same side of boundary line 70 defined in this way, and their rotation directions are opposite to each other.

[0049] That is, in this embodiment, the rotation axis 47 of the first accelerating / relaxing roll 41 and the rotation axis 67 of the first feed roll 61 are located on the same side of the boundary line 70, and the rotation axis 47 of the second accelerating / relaxing roll 42 and the rotation axis 67 of the second feed roll 62 are located on the same side. Therefore, for the pair of accelerating / relaxing rolls 40 and the pair of feed rolls 60, the first accelerating / relaxing roll 41 and the first feed roll 61 rotate in opposite directions, and the second accelerating / relaxing roll 42 and the second feed roll 62 rotate in opposite directions.

[0050] <Guide Roll 50> The guide roll 50 is disposed between the speed-up / relaxation roll 40 and the feed roll 60 in the transport path 110 of the fiber bundle 105. The guide roll 50 is formed in a cylindrical shape, and the outer circumferential surface has a matte surface roughness. The guide roll 50 is disposed so that the direction in which the rotation central axis extends is the first direction X, and is a free roll that can rotate around the rotation central axis in response to an externally input force. The guide roll 50 preferably has a diameter of approximately 30 mm to 100 mm.

[0051] The guide roll 50 is disposed between the speed-increasing relaxation roll 40 and the feed roll 60 in the transport path 110 of the fiber bundle 105, and therefore the fiber bundle 105 is looped around the guide roll 50 between the speed-increasing relaxation roll 40 and the feed roll 60 in the transport path 110 of the fiber bundle 105. That is, the fiber bundle 105 is looped around the guide roll 50 at a position downstream of the second speed-increasing relaxation roll 42 of the pair of speed-increasing relaxation rolls 40, which is located relatively downstream in the transport path 110 of the fiber bundle 105.

[0052] In this embodiment, the guide roll 50 is arranged on the side where the second speed-up relaxation roll 42 is located, with respect to the boundary line 70, which is a line connecting the spaces between the speed-up relaxation rolls 40 and the spaces between the feed rolls 60, and a part of the outer circumferential surface of the guide roll 50 is arranged in the vicinity of the boundary line 70. Therefore, the guide roll 50 can position the fiber bundle 105 wound around the guide roll 50 at a position where it is transported along the boundary line 70 on the downstream side of the guide roll 50 in the transport path 110 of the fiber bundle 105.

[0053] <Contact Range of the Speed-Up Relaxation Roll 40 with the Fiber Bundle 105> A guide roll 50 is arranged downstream of the second speed-increasing relaxation roll 42, and a fiber-spreading bar 30 is arranged upstream of the first speed-increasing relaxation roll 41. The guide roll 50 and the fiber-spreading bar 30 are arranged at positions where the fiber bundle 105 can be brought into contact with the speed-increasing relaxation roll 40 over a range of at least half of the circumference of the speed-increasing relaxation roll 40.

[0054] That is, the guide roll 50 disposed downstream of the second speed-increasing relaxation roll 42 is disposed at a position where a portion of the outer peripheral surface of the guide roll 50 is located near the boundary line 70, which is a line connecting the adjacent speed-increasing relaxation rolls 40 and the adjacent feed rolls 60. Therefore, the guide roll 50 can bring the fiber bundle 105 wound around the second speed-increasing relaxation roll 42 into contact with the second speed-increasing relaxation roll 42 over as wide an area as possible in the circumferential direction of the second speed-increasing relaxation roll 42 in the downstream portion of the second speed-increasing relaxation roll 42. This makes it possible for the guide roll 50 to bring the fiber bundle 105 wound around the second speed-increasing relaxation roll 42 into contact with the second speed-increasing relaxation roll 42 over a range of at least half of the circumferential direction of the second speed-increasing relaxation roll 42.

[0055] Furthermore, the spreading bar 30 that can increase the contact area of ​​the fiber bundle 105 with the first increasing speed relaxation roll 41 is the spreading bar 30 located most downstream on the conveyance path 110, among the multiple spreading bars 30 arranged upstream of the first increasing speed relaxation roll 41. Of the multiple spreading bars 30, the spreading bar 30 located most downstream is arranged closer to the second increasing speed relaxation roll 42 with respect to the position of the midpoint 48a of the line 48 connecting the rotation central axes 47 of the pair of increasing speed relaxation rolls 40, in a direction parallel to the line 48 connecting the rotation central axes 47 of the pair of increasing speed relaxation rolls 40. Therefore, the spreading bar 30 can bring the fiber bundle 105, which is wound around the first increasing speed relaxation roll 41, into contact with the first increasing speed relaxation roll 41 over as wide an area as possible in the circumferential direction of the first increasing speed relaxation roll 41, in the upstream portion of the first increasing speed relaxation roll 41. As a result, the spreading bar 30 located at the most downstream side can contact the fiber bundle 105 wound around the first speed-increasing relaxation roll 41 over a range of at least half of the circumference of the first speed-increasing relaxation roll 41.

[0056] It is preferable that the most downstream spreading bar 30 among the plurality of fiber-spreading bars 30 is arranged at a position where it can contact the fiber bundle 105 over a range of at least half of the circumference of the first speed-increasing relaxation roll 41, and is arranged as close as possible to the first speed-increasing relaxation roll 41. By arranging the most downstream spreading bar 30 among the plurality of fiber-spreading bars 30 as close as possible to the first speed-increasing relaxation roll 41, the fiber bundle 105 can be fed to the first speed-increasing relaxation roll 41 while maintaining the temperature of the fiber bundle 105, which has been increased by heating in the fiber-spreading bar 30.

[0057] <Action of the fiber-spreading device 10> The spread device 10 according to this embodiment has the above-described configuration, and its operation will be described below. When the fiber bundle 105 is spread by the spread device 10, the roving 100 on which the fiber bundle 105 is wound into a cylindrical shape is attached to the unwinding machine 20, and the fiber bundle 105 is pulled out from the roving 100 and wound around the spread bar 30, the speed-up relaxation roll 40, and the guide roll 50, and passed between the pair of feed rolls 60. In this way, the fiber bundle 105 is arranged along the transport path 110 for the fiber bundle 105.

[0058] In this state, the speed-up and relaxation rolls 40 and the feed rolls 60 are rotated. As a result, the fiber bundle 105 is pulled from the upstream side to the downstream side of the conveyance path 110 of the fiber bundle 105 by rotating the feed rolls 60 while sandwiched between the first feed roll 61 and the second feed roll 62. That is, tension acts on the fiber bundle 105 in the direction from the upstream side to the downstream side of the conveyance path 110. Due to the tension thus applied by the feed rolls 60, the fiber bundle 105 is continuously unwound from the unwinding machine 20 to which the roving 100 is attached.

[0059] At this time, the unwinding machine 20 is provided as a back tension roll that generates tension on the fiber bundle 105 in the direction opposite to the traveling direction of the fiber bundle 105. Therefore, the fiber bundle 105 unwound from the unwinding machine 20 by the tension generated by the feed roll 60 is continuously unwound from the unwinding machine 20 while receiving tension from the unwinding machine 20 in the direction opposite to the tension applied by the feed roll 60. That is, the fiber bundle 105 transported on the transport path 110 is transported in a state in which tension is applied.

[0060] The tension acting on the fiber bundle 105 is thus generated by the force of the feed roll 60 pulling the fiber bundle 105 toward the downstream side and the tension in the opposite direction to the traveling direction of the fiber bundle 105 that is applied to the fiber bundle 105 by the unwinding machine 20. For this reason, the magnitude of the tension acting on the fiber bundle 105 can be adjusted by adjusting the strength of the tension exerted by the back tension roll of the unwinding machine 20.

[0061] The fiber bundle 105 unwound from the unwinder 20 first reaches the position of the spreading bar 30, which is arranged downstream of the unwinder 20, and comes into contact with the spreading bar 30. The spreading bar 30 can be heated by passing a heat medium through it, and the fiber bundle 105 that comes into contact with the spreading bar 30 is heated by the heat transferred from the spreading bar 30. The fiber bundle 105 heated by the spreading bar 30 also heats the sizing agent that bundles the carbon fibers, causing the sizing agent to volatilize. This allows the carbon fibers that have been bundled by the sizing agent to move freely, and the fiber bundle 105 becomes more susceptible to deformation.

[0062] In addition, the fiber bundle 105 in contact with the fiber spreading bar 30 is wound around the fiber spreading bar 30, and thus its traveling direction changes at the position of the fiber spreading bar 30. On the other hand, since the fiber bundle 105 is fed while being tensioned, the fiber bundle 105, whose traveling direction changes at the position of the fiber spreading bar 30, is pressed against the fiber spreading bar 30. That is, the fiber bundle 105 fed along the feeding path 110 comes into contact with the fiber spreading bar 30, which is arranged in a non-rotatable state, and passes the position of the fiber spreading bar 30 while being pressed against the fiber spreading bar 30.

[0063] Therefore, when the fiber bundle 105, in which the carbon fibers are more easily movable, is pressed against the spreading bar 30, its shape is deformed in the direction in which it is pressed against the spreading bar 30, for example, in the direction in which its thickness decreases in the radial direction of the rod-shaped spreading bar 30. That is, the shape of the fiber bundle 105 is deformed in the direction in which its width in the first direction X increases, and as a result, the fiber bundle 105 passing the position of the spreading bar 30 is spread by the spreading bar 30.

[0064] Furthermore, a plurality of spreading bars 30 are arranged, and the fiber bundle 105 is pressed against the spreading bars 30 while different surfaces of the fiber bundle 105 are in contact with the plurality of spreading bars 30, and passes through the positions of the spreading bars 30. Therefore, the fiber bundle 105 is heated from both surfaces that contact the spreading bars 30, and is spread by being pressed against the spreading bars 30, resulting in balanced spreading. Note that in this embodiment, the plurality of spreading bars 30 are arranged in a staggered pattern, but the arrangement of the spreading bars 30 is not limited to a regular arrangement such as a staggered arrangement, and can be adjusted as appropriate, as long as the fiber bundle 105 can be spread in a balanced manner.

[0065] The fiber bundle 105 spread by the spreading bar 30 is transported along the transport path 110 and reaches the position of the increasing speed relaxation roll 40. The increasing speed relaxation roll 40 is provided as a pair of a first increasing speed relaxation roll 41 and a second increasing speed relaxation roll 42, and therefore the fiber bundle 105 reaches the position of the first increasing speed relaxation roll 41, which is located relatively more upstream of the first increasing speed relaxation roll 41 and the second increasing speed relaxation roll 42.

[0066] The speed-increasing and relaxation rolls 40, which come into contact with the fiber bundle 105 as the fiber bundle 105 is wound around them, are rotated at an increased peripheral speed within a range of 650% or less of the peripheral speed of the feed rolls 60, and when the rotation speed reaches a set rotation speed, the speed is maintained and the rolls are rotated at a constant speed. On the other hand, the fiber bundle 105 moves along the transport path 110 due to the tension applied by the feed rolls 60, and therefore the movement speed of the fiber bundle 105 is substantially the same as the peripheral speed of the feed rolls 60.

[0067] Therefore, the speed-up relaxation roll 40, which rotates at a constant speed at an increased peripheral speed within a range of 650% or less of the peripheral speed of the feed roll 60, rotates with its outer peripheral surface 44 sliding relative to the fiber bundle 105 wound around the speed-up relaxation roll 40. That is, the first speed-up relaxation roll 41, around which the fiber bundle 105 transported from the fiber-spreading bar 30 is wound, comes into contact with the fiber bundle 105 with its outer peripheral surface 44 sliding relative to the fiber bundle 105.

[0068] The force that the fiber bundle 105 receives from the first speed-increasing relaxation roll 41 as the first speed-increasing relaxation roll 41 comes into contact with the fiber bundle 105 while sliding acts on the fiber bundle 105 as a force in a direction that pushes the fiber bundle 105 in the traveling direction along the transport path 110. As a result, the fiber bundle 105 wound around the first speed-increasing relaxation roll 41 is transported while being pushed slightly in the traveling direction along the transport path 110 by the first speed-increasing relaxation roll 41 that rotates at an increased peripheral speed within a range of 650% or less of the peripheral speed of the feed roll 60.

[0069] When the first speed-increasing relaxation roll 41 comes into sliding contact with the fiber bundle 105 and the fiber bundle 105 is pushed in the traveling direction of the conveyance path 110, the tension acting on the fiber bundle 105 is reduced and the fiber bundle 105 is relaxed. That is, tension acts on the fiber bundle 105 by pulling it from the upstream side to the downstream side of the conveyance path 110 by the feed roll 60 and by applying a force by the unwinding machine 20 in the direction opposite to the direction in which the fiber bundle 105 is pulled by the feed roll 60. That is, tension acts on the fiber bundle 105 by applying a force by the unwinding machine 20 in the direction opposite to the traveling direction of the fiber bundle 105.

[0070] When the first speed-increasing relaxation roll 41 comes into sliding contact with the fiber bundle 105 while sliding against the fiber bundle 105, pushing the fiber bundle 105 in the traveling direction, the force acting on the fiber bundle 105 in the direction opposite to the traveling direction of the fiber bundle 105 is reduced in the portion of the fiber bundle 105 looped around the first speed-increasing relaxation roll 41. As a result, the tension acting on the fiber bundle 105 is reduced in the portion of the fiber bundle 105 looped around the first speed-increasing relaxation roll 41, causing the fiber bundle 105 to relax. As the tension is reduced, the fiber bundle 105 tends to increase in size in the direction perpendicular to the direction in which the tension acts.

[0071] That is, when a large tension acts on the fiber bundle 105 in the extension direction of the fiber bundle 105, the fiber bundle 105 tends to stretch in the extension direction due to the tension, and accordingly, the size of the fiber bundle 105 in the direction perpendicular to the extension direction tends to decrease. When the tension acting on the fiber bundle 105 is reduced in this way, the fiber bundle 105 tends to stretch less in the extension direction of the fiber bundle 105, which is the direction in which the tension was acting, and the fiber bundle 105 tends to assume a free shape due to the reduced tension, so the size of the fiber bundle 105 in the direction perpendicular to the extension direction, which tended to decrease when tension was acting, tends to increase.

[0072] Here, the first speed-increasing relaxation roll 41, which slides in contact with the fiber bundle 105 to push the fiber bundle 105 in the direction of travel along the transport path 110 and reduce the tension of the fiber bundle 105, can be heated by passing a heat medium through the interior. Therefore, the first speed-increasing relaxation roll 41 can heat the fiber bundle 105 that it comes into contact with, and volatilize the sizing agent in the fiber bundle 105, thereby maintaining a state in which the carbon fibers can move freely and easily. As a result, the first speed-increasing relaxation roll 41 can transport the fiber bundle 105 while maintaining a state in which the fiber bundle 105 is easily deformed.

[0073] Furthermore, in the portion of the fiber bundle 105 that is wound around the first speed-increasing relaxation roll 41, the direction of travel of the fiber bundle 105 is changed by the first speed-increasing relaxation roll 41 as a result of being wound around the first speed-increasing relaxation roll 41, and the fiber bundle 105 is pressed against the first speed-increasing relaxation roll 41. This allows the carbon fibers to move freely, and the fiber bundle 105, which is more likely to assume a free shape compared to when tension is applied, deforms in the direction in which it is pressed against the first speed-increasing relaxation roll 41, i.e., in the direction in which its thickness in the radial direction of the first speed-increasing relaxation roll 41 decreases and its width in the first direction X increases.

[0074] As a result, the first speed-increasing relaxation roll 41 makes contact while sliding, and the fiber bundle 105 passing the position of the first speed-increasing relaxation roll 41 while the tension is reduced is spread by the first speed-increasing relaxation roll 41. That is, the tension of the fiber bundle 105 passing the position of the first speed-increasing relaxation roll 41 is reduced by the first speed-increasing relaxation roll 41, increasing the freedom of size in the direction perpendicular to the direction in which the tension acts, and the fiber bundle 105 is spread by being pressed against the first speed-increasing relaxation roll 41, increasing the width in the first direction X.

[0075] In the present embodiment, the fiber bundle 105 is wound around the first speed-increasing relaxation roll 41 by the spreading bar 30 located most downstream among the multiple spreading bars 30, in a state where the fiber bundle 105 is in contact with the first speed-increasing relaxation roll 41 over a range of at least half in the circumferential direction of the first speed-increasing relaxation roll 41. Therefore, the fiber bundle 105 is in contact with the first speed-increasing relaxation roll 41 over a relatively long distance, and is heated over a long distance by the first speed-increasing relaxation roll 41, while the tension is reduced and the fiber bundle is spread.

[0076] Since the second speed-increasing relaxation roll 42 is disposed downstream of the first speed-increasing relaxation roll 41, the fiber bundle 105 spread by the first speed-increasing relaxation roll 41 reaches the position of the second speed-increasing relaxation roll 42. Like the first speed-increasing relaxation roll 41, the second speed-increasing relaxation roll 42 also rotates at a constant speed, increasing its peripheral speed within a range of 650% or less of the peripheral speed of the feed roll 60, so that the outer peripheral surface 44 of the second speed-increasing relaxation roll 42 also comes into sliding contact with the fiber bundle 105. Therefore, the fiber bundle 105 wound around the second speed-increasing relaxation roll 42 is transported while being slightly pushed forward by the second speed-increasing relaxation roll 42 in the traveling direction along the transport path 110.

[0077] Therefore, in the portion of the fiber bundle 105 that is wound around the second speed-increasing relaxation roll 42, the tension acting on the fiber bundle 105 is reduced, and the fiber bundle 105 is relaxed, similar to the portion that is wound around the first speed-increasing relaxation roll 41. Furthermore, like the first speed-increasing relaxation roll 41, the second speed-increasing relaxation roll 42 can also be heated by passing a heat medium through its interior. Therefore, the second speed-increasing relaxation roll 42 can heat the fiber bundle 105 that comes into contact with it, and by volatilizing the sizing agent in the fiber bundle 105, it is possible to maintain a state in which the carbon fibers can move freely. As a result, the second speed-increasing relaxation roll 42 can transport the fiber bundle 105 while maintaining a state in which the fiber bundle 105 is easily deformed.

[0078] Furthermore, in the portion of the fiber bundle 105 that is wound around the second speed-increasing relaxation roll 42, the traveling direction of the fiber bundle 105 is changed by the second speed-increasing relaxation roll 42, and the fiber bundle 105 is pressed against the second speed-increasing relaxation roll 42. Therefore, in the portion of the fiber bundle 105 that is wound around the second speed-increasing relaxation roll 42, the thickness in the radial direction of the second speed-increasing relaxation roll 42 becomes thinner, similar to the portion that is wound around the first speed-increasing relaxation roll 41, and the shape is deformed in a direction that increases the width in the first direction X.

[0079] As a result, the second speed-increasing relaxation roll 42 makes contact while sliding, and the fiber bundle 105 passing the position of the second speed-increasing relaxation roll 42 while the tension is reduced is spread by the second speed-increasing relaxation roll 42. That is, the tension of the fiber bundle 105 passing the position of the second speed-increasing relaxation roll 42 is reduced by the second speed-increasing relaxation roll 42, increasing the freedom of size in the direction perpendicular to the direction in which the tension acts, and the fiber bundle 105 is spread by being pressed by the second speed-increasing relaxation roll 42, increasing the width in the first direction X.

[0080] In this embodiment, the fiber bundle 105 is wound around the second speed-increasing relaxation roll 42 by the guide roll 50 in a state of contact with the second speed-increasing relaxation roll 42 over a range of at least half in the circumferential direction of the second speed-increasing relaxation roll 42. Therefore, the fiber bundle 105 contacts the second speed-increasing relaxation roll 42 over a relatively long distance, and is heated by the second speed-increasing relaxation roll 42 over a long distance while the tension is reduced and the fiber is spread.

[0081] Moreover, the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42, which spread the fiber bundle 105 in this manner, come into contact with different surfaces of the fiber bundle 105. Therefore, the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 heat the fiber bundle 105 from different surfaces while pressing the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 against each other to spread the fiber bundle 105, thereby enabling well-balanced spreading.

[0082] As described above, the speed-increasing relaxation roll 40 reduces the tension of the fiber bundle 105 by slidingly contacting with the fiber bundle 105 and spreading the fiber bundle 105, so the rotation speed of the speed-increasing relaxation roll 40 is preferably set in accordance with the required spread width of the fiber bundle 105. That is, the rotation speed of the speed-increasing relaxation roll 40 is preferably set in accordance with the required spread width of the fiber bundle 105 at a rotation speed that increases the peripheral speed within a range of 650% or less of the peripheral speed of the feed roll 60.

[0083] In addition, the temperature of the speed-up relaxation roll 40 when heating the fiber bundle 105 is preferably adjusted according to the thermal decomposition temperature of the sizing agent used in the fiber bundle 105 or the amount of the sizing agent to be thermally decomposed.

[0084] The fiber bundle 105 spread by the speed-increasing relaxation roll 40 is transported along the transport path 110 and reaches the position of the guide roll 50 arranged downstream of the speed-increasing relaxation roll 40. The fiber bundle 105 is wound around the guide roll 50, and its traveling direction is changed by the guide roll 50. However, because the guide roll 50 is a free roll, the fiber bundle 105 that has reached the position of the guide roll 50 smoothly changes its traveling direction as the guide roll 50 rotates in accordance with the movement of the fiber bundle 105.

[0085] The fiber bundle 105, whose traveling direction is changed by the guide roll 50, has its traveling direction changed to a direction that directs the fiber bundle 105 toward the portion between the first feed roll 61 and the second feed roll 62. That is, the fiber bundle 105 wound around the guide roll 50 has its traveling direction changed by the guide roll 50 to a direction perpendicular to a line 68 connecting the rotation center axes 67 of the pair of feed rolls 60.

[0086] The fiber bundle 105, whose traveling direction has been changed by the guide rolls 50, reaches the position of the feed rolls 60, which are arranged downstream of the guide rolls 50. At that time, the fiber bundle 105 has its traveling direction changed by the guide rolls 50, so the fiber bundle 105, which reaches the position of the feed rolls 60, reaches the part between the first feed roll 61 and the second feed roll 62 of the feed rolls 60. As a result, the fiber bundle 105 comes into contact with the first feed roll 61 and the second feed roll 62 almost simultaneously, and moves downstream of the spread device 10 while being sandwiched between the rotating first feed roll 61 and second feed roll 62. The spread device 10 spreads the fiber bundle 105 in this way, and transports the spread fiber bundle 105 to a process downstream of the spread device 10.

[0087] <Effects of the embodiment> The fiber-spreading device 10 according to the above embodiment includes the speed-increasing relaxation roll 40 that rotates at an increased peripheral speed within a range of 650% or less of the peripheral speed of the feed roll 60 and comes into contact with the fiber bundle 105, and therefore can spread the fiber bundle 105 while reducing the tension in the fiber bundle 105 with the speed-increasing relaxation roll 40. Furthermore, the speed-increasing relaxation roll 40 includes the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 that comes into contact with a surface of the fiber bundle 105 different from the surface that comes into contact with the first speed-increasing relaxation roll 41, and therefore can spread the fiber bundle 105 from both sides of the fiber bundle 105 in a balanced manner. As a result, the fiber bundle 105 that is spread to a wide width can be stably obtained.

[0088] Furthermore, the feed roll 60 and the speed-up relaxation roll 40 located on the same side of a boundary line 70 connecting the midpoint 68a of a line 68 connecting the rotation central axes 67 of the pair of feed rolls 60 and the midpoint 48a of a line 48 connecting the rotation central axes 47 of the pair of speed-up relaxation rolls 40 rotate in opposite directions, so it is possible to efficiently arrange the speed-up relaxation roll 40 that applies a force in a direction that reduces the tension on the fiber bundle 105. As a result, it is possible to reduce the size of the entire fiber-spreading device 10 that can stably obtain a wide-spread fiber bundle 105.

[0089] Furthermore, since the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 are arranged at a predetermined interval, the fiber bundle 105 can be transported from the first speed-increasing relaxation roll 41 to the second speed-increasing relaxation roll 42 without the fiber bundle 105 being sandwiched between the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42. This allows the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 to reduce the tension of the fiber bundle 105 and spread the fiber bundle 105, respectively. As a result, the fiber bundle 105 spread to a wide width can be stably obtained.

[0090] Furthermore, since the guide roll 50 is disposed between the speed-increasing relaxation roll 40 and the feed roll 60 in the conveying path 110 of the fiber bundle 105, the fiber bundle 105 can be made to appropriately reach the portion between the first feed roll 61 and the second feed roll 62 with respect to the feed roll 60. This allows the fiber bundle 105 to be appropriately sandwiched between the first feed roll 61 and the second feed roll 62, and tension can be applied to the fiber bundle 105. Therefore, the fiber bundle 105 can be moved from the upstream side to the downstream side in the conveying direction of the conveying path 110, and by applying tension to the fiber bundle 105, a force can be generated that presses the fiber bundle 105 against the spreading bar 30 and the speed-increasing relaxation roll 40, thereby promoting spreading of the fiber bundle 105. As a result, the fiber bundle 105 that is spread to a wide width can be stably obtained.

[0091] Furthermore, the spreading bar 30 located most downstream on the conveying path 110 is disposed closer to the second increasing-speed relaxation roll 42 than the midpoint 48a of the line 48 connecting the rotation center axes 47 of the pair of speed-increasing relaxation rolls 40 in a direction parallel to the line 48. This allows the fiber bundle 105 wound around the first increasing-speed relaxation roll 41 to come into contact with the first increasing-speed relaxation roll 41 over a range of at least half in the circumferential direction. This allows the fiber bundle 105 wound around the first increasing-speed relaxation roll 41 to come into contact with the first increasing-speed relaxation roll 41 over a relatively long distance, and allows the fiber bundle 105 to be heated over a long distance by the first increasing-speed relaxation roll 41 while being spread with reduced tension. As a result, a wide-spread fiber bundle 105 can be stably obtained.

[0092] Furthermore, when the speed-increasing relaxation roll 40 is viewed in a direction along the rotation center axis 47 of the speed-increasing relaxation roll 40, the fiber bundle 105 is wound around the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 in an S-shape or an inverted S-shape, so that the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 can be efficiently brought into contact with different surfaces of the fiber bundle 105. That is, by winding the fiber bundle 105 around the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 in an S-shape or an inverted S-shape, the second speed-increasing relaxation roll 42 can be brought into contact with a surface of the fiber bundle 105 opposite to the surface with which the first speed-increasing relaxation roll 41 contacted, on the downstream side immediately after the first speed-increasing relaxation roll 41 contacted the fiber bundle 105. This allows the transport path 110 of the fiber bundle 105 to be shortened when the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 are brought into contact with different surfaces of the fiber bundle 105, thereby reducing the size of the area around the speed-increasing relaxation roll 40. As a result, the overall size of the fiber-spreading device 10, which can stably obtain the fiber bundle 105 spread to a wide width, can be reduced.

[0093] Furthermore, because the surfaces of the spreading bar 30, the speed-up relaxation roll 40, and the second feed roll 62 have a matte finish, surface friction can be reduced compared to when the surfaces are plated. This can suppress the generation of fuzz in the fiber bundle 105. In other words, if the surfaces of the spreading bar 30, the speed-up relaxation roll 40, and the second feed roll 62 are plated, the surfaces become flat, and the contact area of ​​the fiber bundle 105 increases when the fiber bundle 105 comes into contact with them. In this case, the frictional force between these members and the fiber bundle 105 increases, and so when the fiber bundle 105 is pressed against these members, the large frictional force may make fuzz more likely to occur on the surface of the fiber bundle 105.

[0094] In contrast, when the surface roughness of the fiber-spreading bar 30, the speed-increasing relaxation roll 40, and the second feed roll 62 is matte, the contact area between these members and the fiber bundle 105 can be reduced. This reduces the frictional force between the fiber-spreading bar 30, the speed-increasing relaxation roll 40, and the second feed roll 62 and the fiber bundle 105, thereby suppressing the generation of fluff in the fiber bundle 105. As a result, the fiber bundle 105 that is spread to a wide width can be stably obtained.

[0095] Furthermore, by setting the distance between the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 as close as possible to about 1 mm to 50 mm, when the fiber bundle 105 is transported from the first speed-increasing relaxation roll 41 to the second speed-increasing relaxation roll 42, the fiber bundle 105 can be transported to the second speed-increasing relaxation roll 42 while maintaining the temperature of the fiber bundle 105 heated by the first speed-increasing relaxation roll 41. As a result, when the fiber bundle 105 is spread by the second speed-increasing relaxation roll 42, the sizing agent of the fiber bundle 105 volatilizes, so that the fiber bundle 105 can be spread in a state where it is easily deformed. As a result, a fiber bundle 105 spread to a wide width can be stably obtained.

[0096] Furthermore, in the fiber-spreading method according to the embodiment, the speed-up relaxation roll 40, which rotates at an increased peripheral speed within a range of not more than 650% of the peripheral speed of the feed roll 60, is brought into contact with the fiber bundle 105, so that the fiber bundle 105 can be spread while the tension of the fiber bundle 105 is reduced by the speed-up relaxation roll 40. Furthermore, different surfaces of the fiber bundle 105 are brought into contact with the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42, so that the fiber bundle 105 can be spread in a balanced manner from both sides of the fiber bundle 105. As a result, the fiber bundle 105 that is spread to a wide width can be stably obtained.

[0097] Furthermore, the speed-increasing relaxation roll 40 increases the peripheral speed within a range of 200% to 650% of the peripheral speed of the feed roll 60, and therefore the fiber bundle 105 can be spread by the speed-increasing relaxation roll 40 while suppressing defects of the fiber bundle 105 upstream of the speed-increasing relaxation roll 40. In other words, when the peripheral speed of the speed-increasing relaxation roll 40 relative to the peripheral speed of the feed roll 60 is less than 200%, the peripheral speed of the speed-increasing relaxation roll 40 is too slow, which may make it difficult for the speed-increasing relaxation roll 40 to effectively reduce the tension of the fiber bundle 105 wound around the speed-increasing relaxation roll 40. In this case, it may be difficult for the speed-increasing relaxation roll 40 to effectively spread the fiber bundle 105. Furthermore, when the peripheral speed of the speed-increasing relaxation roll 40 exceeds 650% of the peripheral speed of the feed roll 60, the peripheral speed of the speed-increasing relaxation roll 40 is too fast, and there is a risk that the force exerted by the speed-increasing relaxation roll 40 in the direction of travel of the fiber bundle 105 will become too large. In this case, there is a risk that the tension of the fiber bundle 105 on the upstream side of the speed-increasing relaxation roll 40 will become too large, and the large tension will press the fiber bundle 105 against the spreading bar 30 with a large force, which may easily cause problems such as the generation of fluff on the surface of the fiber bundle 105 that contacts the spreading bar 30.

[0098] In contrast, when the speed-up relaxation roll 40 is increased in a range of 200% to 650% of the peripheral speed of the feed roll 60, the tension of the fiber bundle 105 wound around the speed-up relaxation roll 40 can be effectively reduced while preventing the tension of the fiber bundle 105 from becoming too large at a position upstream of the speed-up relaxation roll 40. This makes it possible to spread the fiber bundle 105 by the speed-up relaxation roll 40 while suppressing problems such as fuzzing of the fiber bundle 105 upstream of the speed-up relaxation roll 40. As a result, a fiber bundle 105 that is spread to a wide width can be stably obtained.

[0099] [Variations] In the spreader device 10 according to the above-described embodiment, an example of the arrangement of the spreader bars 30, the speed-up and speed-relaxation rolls 40, the guide rolls 50, and the feed rolls 60 has been described, but these arrangements may be arrangements other than those in the above-described embodiment.

[0100] 2 is a schematic diagram showing a modified example of the fiber-spreading device 10 according to the embodiment, in which the first increasing-speed relaxation roll 41 is disposed below the second increasing-speed relaxation roll 42. For example, as shown in FIG. 2, the increasing-speed relaxation roll 40 may be arranged such that the first increasing-speed relaxation roll 41 is disposed below the second increasing-speed relaxation roll 42 in the third direction Z, and the second increasing-speed relaxation roll 42 is disposed above the first increasing-speed relaxation roll 41. In this case, the fiber bundle 105 fed from the most downstream fiber-spreading bar 30 among the plurality of fiber-spreading bars 30 to the increasing-speed relaxation roll 40 is fed to the first increasing-speed relaxation roll 41, which is relatively lower among the pair of increasing-speed relaxation rolls 40.

[0101] Furthermore, the fiber bundle 105 fed to the first speed-increasing relaxation roll 41 is fed from the first speed-increasing relaxation roll 41 to the second speed-increasing relaxation roll 42 located above it, and then fed from the second speed-increasing relaxation roll 42 toward the guide roll 50. In this way, the pair of speed-increasing relaxation rolls 40 only need to be configured so that the fiber bundle 105 is fed from the spreading bar 30 to the first speed-increasing relaxation roll 41 and from the first speed-increasing relaxation roll 41 to the second speed-increasing relaxation roll 42, regardless of the relative positions of the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 in the vertical direction.

[0102] 2, drive motor 45 that supplies drive force to speed-up relaxation roll 40 may be connected to first speed-up relaxation roll 41. In this case, the drive force generated by drive motor 45 is transmitted to first speed-up relaxation roll 41, and the drive force transmitted to first speed-up relaxation roll 41 is transmitted to second speed-up relaxation roll 42 via a power transmission mechanism. As a result, first speed-up relaxation roll 41 and second speed-up relaxation roll 42 each rotate about their respective rotation central axes 47 by the drive force transmitted from drive motor 45.

[0103] Furthermore, in the above-described embodiment, the pair of feed rolls 60 are arranged side by side in the third direction Z, but the direction in which the pair of feed rolls 60 are arranged may be a direction other than the third direction Z. FIG. 3 is a schematic diagram showing a modified example of the fiber-spreading device 10 according to the embodiment, in which the pair of feed rolls 60 are arranged side by side in the second direction Y. FIG. 4 is a schematic diagram showing a modified example of the fiber-spreading device 10 according to the embodiment, in which the pair of feed rolls 60 are arranged side by side in the second direction Y. For example, as shown in FIGS. 3 and 4 , the pair of feed rolls 60 may be a first feed roll 61 and a second feed roll 62 arranged side by side in the second direction Y. In this case, the first feed roll 61 and the second feed roll 62 sandwich the fiber bundle 105 from both sides in the second direction Y and transport it in the third direction Z. Therefore, the fiber bundle 105 transported from the guide roll 50 to the feed roll 60 is transported along the third direction Z so that the fiber bundle 105 can be sandwiched between the pair of feed rolls 60 from both sides in the second direction Y.

[0104] 3 and 4, the guide roll 50 is disposed above the feed roll 60 in the third direction Z, and the fiber bundle 105 transported from the guide roll 50 toward the feed roll 60 is transported from the upper side in the third direction Z toward the feed roll 60. As a result, the feed roll 60 transports the fiber bundle 105, which has been spread by the spreading bar 30 and the speed-up relaxation roll 40, downward in the third direction Z.

[0105] Furthermore, when the first feed roll 61 and the second feed roll 62 are arranged side by side in the second direction Y, the speed-up relaxation roll 40 may be arranged such that the first speed-up relaxation roll 41 is arranged on the upper side and the second speed-up relaxation roll 42 is arranged on the lower side, as shown in Figure 3, or such that the first speed-up relaxation roll 41 is arranged on the lower side and the second speed-up relaxation roll 42 is arranged on the upper side, as shown in Figure 4.

[0106] Furthermore, in the above-described embodiment, the pair of speed-increasing relaxation rolls 40 are arranged side by side in the third direction Z, but the direction in which the pair of speed-increasing relaxation rolls 40 are arranged side by side may be a direction other than the third direction Z. FIG. 5 is a schematic diagram showing a modified example of the fiber-spreading device 10 according to the embodiment, in which the pair of speed-increasing relaxation rolls 40 are arranged side by side in the second direction Y. FIG. 6 is a schematic diagram showing a modified example of the fiber-spreading device 10 according to the embodiment, in which the pair of speed-increasing relaxation rolls 40 are arranged side by side in the second direction Y. For example, as shown in FIGS. 5 and 6, the pair of speed-increasing relaxation rolls 40 may be a first speed-increasing relaxation roll 41 and a second speed-increasing relaxation roll 42 arranged side by side in the second direction Y.

[0107] In this case, the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 may be arranged, for example, as shown in Fig. 5 , such that the first speed-increasing relaxation roll 41, to which the fiber bundle 105 is fed from the fiber spreading bar 30, is positioned closer to the feed roll 60 in the second direction Y, and the second speed-increasing relaxation roll 42, which is positioned downstream of the first speed-increasing relaxation roll 41, is positioned closer to the unwinder 20 in the second direction Y. Alternatively, as shown in Fig. 6 , the first speed-increasing relaxation roll 41, to which the fiber bundle 105 is fed from the fiber spreading bar 30, is positioned closer to the unwinder 20 in the second direction Y, and the second speed-increasing relaxation roll 42, which is positioned downstream of the first speed-increasing relaxation roll 41, is positioned closer to the feed roll 60 in the second direction Y.

[0108] Furthermore, both the direction in which the pair of speed-increasing relaxation rolls 40 are lined up and the direction in which the pair of feed rolls 60 are lined up may be a direction other than the third direction Z. FIG. 7 is a schematic diagram showing a modified example of the fiber-spreading device 10 according to the embodiment, in which the pair of speed-increasing relaxation rolls 40 and the pair of feed rolls 60 are lined up in the second direction Y. FIG. 8 is a schematic diagram showing a modified example of the fiber-spreading device 10 according to the embodiment, in which the pair of speed-increasing relaxation rolls 40 and the pair of feed rolls 60 are lined up in the second direction Y. As shown in FIGS. 7 and 8, the direction in which the pair of speed-increasing relaxation rolls 40 and the pair of feed rolls 60 are lined up may be such that the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 are lined up in the second direction Y, and the first feed roll 61 and the second feed roll 62 are lined up in the second direction Y.

[0109] In this case, as shown in Fig. 7, the first speed-increasing relaxation roll 41, to which the fiber bundle 105 is fed from the fiber spreading bar 30, may be arranged on the opposite side to the side where the unwinding machine 20 is located in the second direction Y, and the second speed-increasing relaxation roll 42, which is arranged on the downstream side of the first speed-increasing relaxation roll 41, may be arranged closer to the unwinding machine 20 in the second direction Y. Alternatively, as shown in Fig. 8, the first speed-increasing relaxation roll 41, to which the fiber bundle 105 is fed from the fiber spreading bar 30, may be arranged closer to the unwinding machine 20 in the second direction Y, and the second speed-increasing relaxation roll 42, which is arranged on the downstream side of the first speed-increasing relaxation roll 41, may be arranged on the opposite side to the side where the unwinding machine 20 is located in the second direction Y.

[0110] As described above, the arrangement of the spreading bar 30, the speed-up / relaxation roll 40, the guide roll 50, and the feed roll 60 may be other than that of the embodiment described above, and it is preferable that the arrangement be set appropriately based on the position where the spreading device 10 is placed, the environment in which it is placed, etc.

[0111] Furthermore, in the above-described embodiment, the speed-up relaxation roll 40 is configured such that the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 are connected via a power transmission mechanism, and both the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42 are rotated by the driving force generated by one drive motor 45, but a drive motor 45 may be provided for each of the first speed-up relaxation roll 41 and the second speed-up relaxation roll 42.

[0112] Similarly, the feed roll 60 has a first feed roll 61 and a second feed roll 62 connected via a power transmission mechanism, and both the first feed roll 61 and the second feed roll 62 rotate by the driving force generated by a single drive motor 65, but the drive motor 65 may be provided on each of the first feed roll 61 and the second feed roll 62.

[0113] Furthermore, in the above-described embodiment, two speed-increasing relaxation rolls 40, namely, first speed-increasing relaxation roll 41 and second speed-increasing relaxation roll 42, are used, but the number of speed-increasing relaxation rolls 40 may be other than two, and there may be three or more speed-increasing relaxation rolls 40. The number of speed-increasing relaxation rolls 40, which rotate at a peripheral speed increased relative to the peripheral speed of feed roll 60, is not limited as long as it is two or more.

[0114] Furthermore, although three spreading bars 30 are provided in the above-described embodiment, the number of spreading bars 30 may be other than three. It is preferable to determine the number of spreading bars 30 to be arranged depending on the tension applied to the fiber bundle 105, the contact angle of the fiber bundle 105 with the spreading bars 30 when the fiber bundle 105 is wound around the spreading bars 30, the heating time of the fiber bundle 105 by the spreading bars 30, etc.

[0115] Furthermore, in the above-described embodiment, the magnitude of the tension acting on the fiber bundle 105 is adjusted by adjusting the strength of the tension applied by the back tension roll of the unwinding machine 20, but the tension acting on the fiber bundle 105 may be adjusted by other methods. The magnitude of the tension acting on the fiber bundle 105 may be adjusted by, for example, changing the number of fiber spreading bars 30, the diameter of the fiber spreading bars 30, the angle at which the fiber bundle 105 is wound around the fiber spreading bars 30, etc.

[0116] <Test of Spreading of Fiber Bundle 105 by Spreading Device 10> The inventors conducted a test on the amount of fiber spreading when the fiber bundle 105 is spread by the fiber spreading device 10. Next, an evaluation test on the relationship between the circumferential speed of the speed-up relaxation roll 40 relative to the circumferential speed of the feed roll 60 and the amount of fiber spreading of the fiber bundle 105 will be described.

[0117] Fig. 9 is a schematic diagram showing the device configuration of the spreader 10 used in the evaluation test. The evaluation test for the spread amount of the fiber bundle 105 was performed using a spreader 10 in which five spread bars 30 are provided, the first speed-increasing relaxation roll 41 and the second speed-increasing relaxation roll 42 are arranged side by side in the second direction Y, and the first feed roll 61 and the second feed roll 62 are also arranged side by side in the second direction Y, as shown in Fig. 9. The evaluation test used a carbon fiber tow TR50S15L (15,000 filaments, filament diameter 7 µm) manufactured by Mitsubishi Chemical Corporation as the fiber bundle 105, and was performed by attaching a plurality of the fiber bundles 105 to the spreader 10 shown in Fig. 9 and determining the spread state of the fiber bundles 105 when they were spread by the spreader 10.

[0118] The evaluation test for the spread amount of the fiber bundle 105 was performed by setting the feeding speed of the fiber bundle 105 in the spread device 10 to 5 m / min and varying the peripheral speed of the speed-up relaxation roll 40 relative to the peripheral speed of the feed roll 60 to spread the fiber bundle 105. The evaluation test was performed by measuring the spread amount of the fiber bundle 105 and the tension of the fiber bundle 105 when the fiber bundle 105 was spread by the spread device 10 in this way, and determining whether or not fluff occurred in the fiber bundle 105.

[0119] 10 is a table showing the results of the evaluation test. Regarding the spread amount of the fiber bundle 105, the position where the fiber bundle 105 is wound around the first speed-increasing relaxation roll 41 is defined as the first spread width measuring position S1, and the position where the fiber bundle 105 is wound around the second speed-increasing relaxation roll 42 is defined as the second spread width measuring position S2, and the spread width of the fiber bundle 105 in the first direction X is measured at each position. The value obtained by subtracting the spread width of the fiber bundle 105 at the first spread width measuring position S1 from the spread width of the fiber bundle 105 measured in this way at the second spread width measuring position S2 is defined as the spread amount of the fiber bundle 105 spread by the speed-increasing relaxation roll 40 in this evaluation test.

[0120] The tension of the fiber bundle 105 is measured with a handheld tension meter at a position between the spreading bar 30 and the first speed-increasing relaxation roll 41 on the transport path 110 of the fiber bundle 105, which is designated as a first tension measurement position T1, and at a position between the guide roll 50 and the feed roll 60, which is designated as a second tension measurement position T2. ​​The tension of the fiber bundle 105 reduced by the speed-increasing relaxation roll 40 is the tension difference obtained by subtracting the tension of the fiber bundle 105 at the second tension measurement position T2 from the tension of the fiber bundle 105 at the first tension measurement position T1 measured in this manner.

[0121] The spread amounts of the fiber bundles 105 measured in this manner were evaluated by calculating the average value of the spread amounts of three of the multiple fiber bundles 105 attached to the spreading device 10, that is, the average value of the spread amounts of the three pass lines. Similarly, the tension difference of the fiber bundle 105 was evaluated by calculating the average value of the tension differences of the three pass lines.

[0122] The presence or absence of fluff in the fiber bundle 105 was determined by visually observing the fiber bundle 105 that had passed through the fiber-spreading bar 30 when the fiber-spreading device 10 performed fiber-spreading.

[0123] In the evaluation tests conducted as described above, tests were conducted under nine conditions: Examples 1 to 6, which are examples in which the circumferential speed ratio, which is the ratio of the circumferential speed of the speed-up relaxation roll 40 to the circumferential speed of the feed roll 60, was varied, and Comparative Examples 1 to 3, which were compared with these Examples. Of these, Example 1 had a circumferential speed ratio, which is the ratio of the circumferential speed of the speed-up relaxation roll 40 to the circumferential speed of the feed roll 60, of 150%, Example 2 had a circumferential speed ratio of 200%, Example 3 had a circumferential speed ratio of 250%, Example 4 had a circumferential speed ratio of 400%, Example 5 had a circumferential speed ratio of 600%, and Example 6 had a circumferential speed ratio of 650%. In contrast, Comparative Example 1 had a circumferential speed ratio of 50%, Comparative Example 2 had a circumferential speed ratio of 100%, and Comparative Example 3 had a circumferential speed ratio of 700%.

[0124] As a result of conducting a test to spread the fiber bundle 105 under these conditions, the results shown in FIG. 10 were obtained regarding the spread amount of the fiber bundle 105, the tension difference of the fiber bundle 105, and the presence or absence of fluffing of the fiber bundle 105 at the spreading bar 30.

[0125] That is, when the peripheral speed of the accelerating relaxation roll 40 is low relative to the peripheral speed of the feed roll 60 as in Comparative Example 1, or when the peripheral speeds are the same as those of the feed roll 60 as in Comparative Example 2, it is difficult to reduce the tension of the fiber bundle 105 by the accelerating relaxation roll 40, making it difficult to effectively increase the amount of fiber spreading of the fiber bundle 105. Furthermore, when the peripheral speed of the accelerating relaxation roll 40 exceeds 650% relative to the peripheral speed of the feed roll 60 as in Comparative Example 3, the peripheral speed of the accelerating relaxation roll 40 is too fast relative to the peripheral speed of the feed roll 60, and there is a risk that the tension of the fiber bundle 105 on the upstream side of the accelerating relaxation roll 40 will become too large. In this case, when the fiber bundle 105 passes the position of the fiber spreading bar 30, it is rubbed with a large force against the fiber spreading bar 30, and therefore fuzz is likely to occur at the position of the fiber spreading bar 30.

[0126] In contrast, when the peripheral speed of the accelerating-speed relaxation roll 40 is increased within a range of 650% or less relative to the peripheral speed of the feed roll 60 as in Examples 1 to 6, it was confirmed that the tension of the fiber bundle 105 can be effectively reduced by the accelerating-speed relaxation roll 40, and therefore the amount of opening of the fiber bundle 105 can be increased by the accelerating-speed relaxation roll 40. That is, in this test, it was confirmed that a pair of accelerating-speed relaxation rolls 40 was disposed between the spreading bar 30 and the feed roll 60 in the transport path 110, and the accelerating-speed relaxation roll 40 was rotated while increasing the peripheral speed within a range of 650% or less relative to the peripheral speed of the feed roll 60, thereby stably obtaining a fiber bundle 105 that was spread to a wide width. [Explanation of symbols]

[0127] 10...spreading device, 20...unwinding machine, 30...spreading bar, 40...accelerating relaxation roll, 41...first increasing speed relaxation roll, 42...second increasing speed relaxation roll, 44...outer periphery, 45...drive motor, 47...rotation center shaft, 50...guide roll, 60...feed roll, 61...first feed roll, 62...second feed roll, 64...outer periphery, 65...drive motor, 66...air cylinder, 67...rotation center shaft, 70...boundary line, 100...roving, 105...fiber bundle, 110...conveying path

Claims

1. a payout machine that continuously pays out a long fiber bundle obtained by bundling carbon fibers with a sizing agent; a pair of feed rolls each formed in a cylindrical shape, which rotate in opposite directions while sandwiching the fiber bundle unwound from the unwinder between them, thereby transporting the fiber bundle downstream in a transport path of the fiber bundle; a plurality of spreading bars formed in a rod shape and arranged in the conveying path between the unwinder and the feed roll, the plurality of spreading bars being arranged at positions where they alternately come into contact with different surfaces of the fiber bundle as they move from the upstream side to the downstream side of the conveying path; a pair of speed-increasing relaxation rolls each formed in a cylindrical shape and disposed between the fiber-spreading bar and the feed roll in the transport path, rotating at a peripheral speed increased within a range of 650% or less of the peripheral speed of the feed roll, and having outer circumferential surfaces in contact with the fiber bundle; Equipped with The pair of speed-increasing relaxation rolls are a first speed-increasing relaxation roll disposed downstream of the fiber-spreading bar in the conveying path; a second speed-increasing relaxation roll that is disposed between the first speed-increasing relaxation roll and the feed roll in the transport path and that comes into contact with a surface of the fiber bundle different from a surface that comes into contact with the first speed-increasing relaxation roll, When the speed-increasing relaxation roll is viewed in a direction along the rotation center axis of the speed-increasing relaxation roll, the fiber bundle is wound around the first speed-increasing relaxation roll and the second speed-increasing relaxation roll in an S-shape or an inverted S-shape, so that the first speed-increasing relaxation roll and the second speed-increasing relaxation roll come into contact with different surfaces of the fiber bundle, the pair of speed-up relaxation rolls are each in contact with the fiber bundle over a range of at least half of the circumferential direction of the speed-up relaxation roll, A drive motor is connected to the second speed-up relaxation roll, the first speed-up relaxation roll and the second speed-up relaxation roll are connected via a power transmission mechanism, and a driving force transmitted from the drive motor to the second speed-up relaxation roll is transmitted to the first speed-up relaxation roll via the power transmission mechanism.

2. 2. The fiber-spreading device according to claim 1, wherein, when the feed roll and the speed-up relaxation roll are viewed in a direction along the central axes of rotation of the feed roll and the speed-up relaxation roll, the feed roll and the speed-up relaxation roll whose central axes of rotation are located on the same side of a boundary line defined by a straight line connecting a midpoint of a line connecting the central axes of rotation of each of the pair of feed rolls and a midpoint of a line connecting the central axes of rotation of each of the pair of speed-up relaxation rolls are such that the rotation direction of the speed-up relaxation roll is opposite to the rotation direction of the feed roll.

3. The fiber-spreading device according to claim 1 or 2, wherein the first speed-increasing relaxation roll and the second speed-increasing relaxation roll are arranged at a predetermined interval.

4. The fiber-spreading device according to any one of claims 1 to 3, further comprising a guide roll formed in a cylindrical shape and arranged between the speed-up / relaxation roll and the feed roll in the transport path.

5. 5. The fiber-spreading device according to any one of claims 1 to 4, wherein the fiber-spreading bar located most downstream in the conveyance path is arranged closer to the second speed-up relaxation roll with respect to a midpoint of a line connecting the rotation central axes of the pair of speed-up relaxation rolls in a direction parallel to the line connecting the rotation central axes of the pair of speed-up relaxation rolls.

6. a fiber-spreading method comprising: continuously unwinding a long fiber bundle obtained by bundling carbon fibers with a sizing agent from a unwinding machine; sandwiching the fiber bundle unwound from the unwinding machine between a pair of feed rolls rotating in opposite directions and transporting the fiber bundle downstream in a transport path of the fiber bundle; and alternately bringing different surfaces of the fiber bundle into contact with a plurality of rod-shaped fiber-spreading bars arranged between the unwinding machine and the feed rolls in the transport path as the fiber bundle moves from the upstream side to the downstream side in the transport path, thereby spreading the fiber bundle; a first speed-increasing relaxation roll disposed downstream of the fiber-spreading bar in the conveying path, the first speed-increasing relaxation roll being cylindrical and rotating at a peripheral speed that is 650% or less of the peripheral speed of the feed roll; and a second speed-increasing relaxation roll disposed between the first speed-increasing relaxation roll and the feed roll in the conveying path, the first speed-increasing relaxation roll and the second speed-increasing relaxation roll being connected to each other via a power transmission mechanism, and the fiber bundle is brought into contact with outer peripheral surfaces of the pair of speed-increasing relaxation rolls, the drive force of a drive motor being transmitted to the second speed-increasing relaxation roll being transmitted to the first speed-increasing relaxation roll via the power transmission mechanism, a fiber-spreading method in which the fiber bundle is wound around the first speed-up relaxation roll and the second speed-up relaxation roll in an S-shape or an inverted S-shape when the speed-up relaxation rolls are viewed in a direction along the central axis of rotation of the speed-up relaxation roll, so that different surfaces of the fiber bundle come into contact with the first speed-up relaxation roll and the second speed-up relaxation roll, and the fiber bundle comes into contact with each of the pair of speed-up relaxation rolls over a range of at least half of the circumference of each of the speed-up relaxation rolls.

7. The fiber-spreading method according to claim 6 , wherein the speed-up / relaxation roll increases the peripheral speed of the speed-up / relaxation roll within a range of 200% to 650% of the peripheral speed of the feed roll.

Images