JP2024176573A - Fiber bundle spreading method and device - Google Patents

Abstract

[Problem] In a method for spreading a fiber bundle while bending it by passing a fluid through it, a member that forms a bend is placed in a fiber-spreading processing section, and the fiber bundle is alternately tensioned and relaxed in a short period of time to spread it. However, since the flow of fluid acting on the fiber bundle due to the member fluctuates greatly in a short period of time, there are problems such as low fiber-spreading efficiency and large device vibration.
[Solution] A deflection forming member having an opening through which a fluid passes applies tension and relaxation to the fiber bundle, and the fluid passing through the opening passes through an area near the maximum push-in position of the fiber bundle, deflecting the fibers in the direction of the fluid passage while moving the fibers in the width direction and spreading them out.
[Selected figure] Figure 3

Description

The present invention relates to a method and device for spreading a fiber bundle, which is made by pulling and bundling a large number of fibers from a yarn supplier, transporting the bundle, and spreading the bundle by passing a fluid through the fiber bundle as it is being transported, thereby bending the fibers and moving them in the width direction.

Fiber-reinforced composite materials, which are made of reinforcing fibers such as carbon fiber or glass fiber and a thermosetting resin such as epoxy resin or a thermoplastic resin such as PA6, PPS, or PEEK as a matrix, are lightweight and have excellent mechanical properties and corrosion resistance, and therefore have come to be widely used in products in a variety of fields, including the transportation field such as aircraft and automobiles, industrial applications such as machine tool parts and robot arms, and sports fields such as fishing rods and golf shafts.

The most commonly used method for molding this fiber-reinforced composite material is to use a sheet-like intermediate material called a prepreg sheet, which is made by impregnating the spaces between the individual fibers of the reinforcing fiber bundles with a resin that acts as a matrix. For example, prepreg sheets are laminated in various directions and then heated and pressurized to form the molded product. The molded product obtained by this method is highly elastic and strong, taking advantage of the properties of the long fibers. In another molding method, the prepreg sheets are processed into chopped tape strips, which are then spread inside a mold and heated and pressurized, making it possible to obtain molded products with complex shapes that are lightweight and have excellent mechanical properties.

In recent years, there has been an increasing need for thin prepreg sheets with good fiber dispersion. Thin prepreg sheets are not only used to obtain thin molded bodies, but also allow for a variety of designs that take advantage of the anisotropic characteristics of the excellent physical properties in the long fiber direction. They have also been found to improve the mechanical properties of molded bodies made by laminating prepreg sheets or chopped tapes, and are expected to further expand the uses of fiber-reinforced composite materials. In order to meet the demand for such uniform, thin prepreg sheets, there is also a need for technology to open reinforcing fiber bundles.

In addition, in the manufacture of prepreg sheets, spreading reinforcing fiber bundles is also necessary to reduce material costs. In order to make uniform and thin prepreg sheets, it is common to make them by arranging reinforcing fiber bundles with a small number of fibers (filaments) in one direction. However, since reinforcing fiber bundles with a small number of filaments are expensive, it is desirable to use reinforcing fiber bundles with as many filaments as possible. For this reason, a method in which a reinforcing fiber bundle with a large number of filaments is spread to produce a spread fiber sheet of thin reinforcing fiber bundles and then made into a prepreg sheet makes it possible to make uniform and thin prepreg sheets with reduced material costs.

As a method for spreading multiple fiber bundles, the present inventors have proposed methods such as those described in Patent Document 1 and Patent Document 2. These methods involve applying a fluid to the fiber bundle being conveyed in a direction intersecting the conveying direction, bending the fiber bundle while moving each fiber in the width direction, and spreading the fiber bundle. In order to impart bending to the multiple fiber bundles being conveyed, the method shows a method in which a member that comes into contact with the fiber bundle (called a contact member) is used to push the fiber bundle in a direction intersecting the conveying direction, and then repeatedly moving the contact member away from the pushed-in fiber bundle.

These methods make it possible to spread multiple fiber bundles widely with good fiber distribution. In the method of Patent Document 2, the contact member rotates to repeatedly push the fiber bundles in and away from the fiber bundles at high speed, making it possible to achieve high-quality, wide spreading at high speed.

Patent No. 4740131 Patent No. 5553074

These methods can be performed by an apparatus equipped with a fluctuation imparting section that repeatedly applies the action of pushing the fiber bundle with the contact member and the action of moving the contact member away from the fiber bundle in the pushed-in state, and a fiber-spreading processing section that applies a fluid to the fiber bundle to bend it into a curved shape and move each fiber in the width direction. The apparatus has a contact member of the fluctuation imparting section arranged in the upper part of an air cavity tube (the upper part is open, and the lower part is connected to a suction pump that sucks in fluid) that constitutes the fiber-spreading processing section, and transports the fiber bundle to the downstream side where the fluid of the contact member is sucked in to perform fiber-spreading, thereby making it possible to achieve wide and high-quality fiber-spreading.

However, when the fiber bundle bends inside the air cavity tube, the fluid acting on the fiber bundle is sucked into the air cavity tube around the contact member and acts on the fiber bundle, so it is believed that the sucked-in fluid does not act efficiently on the fiber bundle.

Furthermore, these methods cause large vibrations throughout the fiber-spreading processing section, resulting in problems such as shaking of the device, loosening of screws, damage to parts, and loud noise. This is believed to be due to the fact that when the contact member rotates or vibrates vertically within the fiber-spreading processing section, the area of the region into which fluid flows into the fiber-spreading processing section changes significantly when the contact member pushes the fiber bundle and when it moves away from the fiber bundle. In particular, the vibration increases as the fiber-spreading processing speed increases, posing problems such as device durability and noise when high-speed fiber-spreading processing is performed continuously.

Therefore, the present invention aims to provide a fiber bundle spreading method and device that can perform fiber spreading by allowing a fluid to act efficiently on the fiber bundle.

The fiber-spreading method of the present invention involves drawing out and conveying a fiber bundle formed by aligning and bundling a large number of fibers from a yarn supplier, pushing a part of the fiber bundle in a direction intersecting the conveying direction while contacting a deflection-forming member to place the fiber bundle in a tensed state, and then moving the deflection-forming member away from the tensed fiber bundle to place the fiber bundle in a relaxed state in a region where a fluctuating operation is repeatedly performed, passing a fluid through the fiber bundle and moving the fibers in the width direction while bending them in the direction of passage of the fluid to spread the fiber bundle. In this method, an opening is formed in the deflection-forming member through which the fluid passes, and the fluid that has passed through the opening passes through a region near the maximum pushing position of the fiber bundle due to the operation of the deflection-forming member, bending the fibers in the direction of passage of the fluid and moving the fibers in the width direction to spread the fiber bundle. Furthermore, the deflection-forming member rotates to repeatedly apply fluctuating operations of tension and relaxation to the fiber bundle. Furthermore, the deflection forming member vibrates in a direction intersecting the feeding direction of the fiber bundle, and repeatedly applies fluctuating motions of tension and relaxation to the fiber bundle. Furthermore, the relationship between the deflection section length, which is the length in the feeding direction of the region where the fiber bundle is deflected, and the fluid action section length, which is the length in the feeding direction of the region where the fluid acts on the deflected fiber bundle and passes through, is such that the deflection section length > the fluid action section length. Furthermore, a region in which a fluid acts on the fiber bundle being fed to deflect the fibers and move them in the width direction to spread them is set at multiple locations on the feeding path of the fiber bundle. Furthermore, the deflection forming member is provided with a width restriction guide that restricts the spread width of the fiber bundle being fed, and the fiber bundle is spread while gradually expanding the spread width. Furthermore, a plurality of the fiber bundles are lined up in the width direction and fed, and each of the fiber bundles is spread.

The fiber bundle spreading device according to the present invention includes a fiber spreading processing section that spreads the fiber bundle by applying a fluid to the fiber bundle being conveyed, while bending the fibers and moving them in the width direction, and a bending forming section that arranges a bending forming member having an opening through which the fluid passes within the fiber spreading processing section, and that repeatedly performs a fluctuating operation in which the bending forming member pushes the fiber bundle in a direction intersecting the conveying direction to place it in a tensed state, and separates the bending forming member from the tensed fiber bundle to place it in a relaxed state. Furthermore, the bending forming member includes a plurality of pushing members that push the fiber bundle being conveyed in a direction intersecting the conveying direction, and an attachment member that is attached to the pushing members so as to form the openings at intervals that allow the fluid to pass through. Furthermore, the pushing members are formed in a roll shape.

By having the above-mentioned configuration, the present invention can reduce the fluctuation of the fluid passing through the fiber bundle and perform the fiber-spreading action efficiently. In addition, by reducing the fluctuation of the fluid passing through the fiber bundle, it is possible to reduce the vibration generated in the entire fiber-spreading processing section, thereby reducing problems such as shaking of the device, loosening of screws, damage to the shaft of the components, and high noise.

Here, the conveying direction of the fiber bundle means the direction of the conveying path of the conveyed fiber bundle, and in the case where the conveying path is defined by a guide member such as a guide roll, it means the direction in which the fiber bundle is stretched on the conveying path.

1 is a schematic side view of a fiber spreading device according to the present invention. FIG. 2 is a schematic diagram of a pivoting deflection forming member according to the present invention; 4 is a schematic diagram showing a state in which a plurality of fiber bundles are spread by a rotating deflection forming member according to the present invention. FIG. 6A and 6B are explanatory diagrams regarding air flow caused by a rotating deflection forming member according to the present invention. 11 is a schematic diagram of another embodiment of a pivoting flexure forming member according to the present invention; FIG. 1 is a schematic diagram of a deflection forming member that vertically vibrates in a direction intersecting with the feeding direction of the fiber bundle according to the present invention. FIG. FIG. 4 is an explanatory diagram relating to the length of a section in which the fiber bundle according to the present invention is bent and the length of a section in which a fluid acts on and passes through the fiber bundle. FIG. 4 is a schematic plan view of a fiber opening device according to another embodiment of the present invention. FIG. 4 is a schematic side view of a fiber spreading device according to another embodiment of the present invention. 13 is an explanatory diagram regarding fiber spreading when a rotating contact member according to a conventional example is used. FIG. FIG. 11 is an explanatory diagram regarding dimensional settings of a fiber-spreading processing section and a bend forming section in the embodiment. FIG. 11 is an explanatory diagram regarding dimensional settings of a fiber-spreading processing section and a bend forming section in the embodiment. 13 is a result showing a vibration state during fiber spreading at a processing speed of 15 m/min in the air cavity tube portion of the fiber spreading device according to the present invention. 13 is a result showing a vibration state during fiber spreading at a processing speed of 40 m/min in the cavity tube portion of the fiber spreading device according to the present invention. 13 is a result showing a vibration state during fiber spreading at a processing speed of 15 m/min in a cavity tube portion of a fiber spreading device according to the prior art. 13 is a result showing a vibration state during fiber spreading at a processing speed of 40 m/min in a cavity tube portion of a fiber spreading device according to the prior art.

The following describes an embodiment of the present invention with reference to the drawings. Note that the embodiment described below is a preferred example of the present invention, and therefore various technical limitations are imposed. However, the present invention is not limited to these forms unless otherwise specified in the following description.

Figure 1 is a schematic side view of a fiber-spreading device according to the present invention. This device example includes a yarn supplying section 1 that supplies multiple fiber bundles Tm, a guide section 2 that guides each of the supplied fiber bundles Tm, a deflection forming section 3 that performs a fluctuating operation to deflect and temporarily relax each of the transported fiber bundles Tm, a fiber-spreading processing section 4 that spreads each of the transported fiber bundles Tm, a heating section 5 that blows hot air onto each of the fiber bundles Tm to heat them, and a take-up section 6 that clamps and transports the spread yarn Ts formed by spreading each of the fiber bundles.

The fiber bundle Tm, which is a bundle of multiple long fibers, is wound around a bobbin-type yarn supplier 11, and as the spread yarn Ts is drawn in by the take-up section 6, the yarn supplier 11 rotates and the fiber bundle Tm is unwound. Note that, although five yarn suppliers are set in FIG. 1, the number of fiber bundles Tm supplied may be one, or five or more may be set to produce a wide spread yarn sheet.

Examples of fiber materials used for the fiber bundle Tm include reinforced fiber bundles made of high-strength fibers such as carbon fiber bundles, glass fiber bundles, aramid fiber bundles, and ceramic fiber bundles, and thermoplastic resin fiber bundles made of thermoplastic synthetic fibers such as polyethylene, polypropylene, nylon 6, nylon 66, nylon 12, polyethylene terephthalate, polyphenylene sulfide, and polyether ether ketone. For example, the number of fibers in a carbon fiber bundle is generally 12,000 to 24,000, but in the present invention, a fiber bundle with a number of fibers exceeding 24,000 (for example, 50,000) can also be used.

In the example of FIG. 1, a yarn supply motor (not shown in FIG. 1) is attached to the yarn supplier 11, and the amount of fiber unwound from the yarn supplier 11 can be adjusted by rotating the yarn supply motor. The fiber bundle Tm unwound from the yarn supplier 11 is fed to the guide section 2, where it is conveyed with a constant tension. In the guide section 2, the fiber bundle Tm is first pulled out in a predetermined pull-out direction by the rotating guide roll 21.

The fiber bundle Tm pulled out in a predetermined direction by the guide roll 21 is transported to the tensioning section 22. The tensioning section 22 includes a pair of support rolls 221 arranged at a predetermined interval in the transport direction D of the fiber bundle Tm, and a tensioning roll 222 that applies tension to the fiber bundle Tm between the pair of support rolls 221. The fiber bundle Tm is set and transported so that it wraps around from the upper side of the support rolls 221 to the lower side of the tensioning roll 222. When the length of the fiber bundle Tm passing between the support rolls 221 changes, the tensioning roll 222 rises and falls accordingly. The rising and lowering movement of the tensioning roll 222 is detected by an upper limit position detection sensor 223 and a lower limit position detection sensor 224.

When the tensioning roll 222 rises and is detected by the upper limit position detection sensor 223, the payout amount of the yarn supply motor connected to the yarn supplier 11 increases, and the feed amount of the fiber bundle Tm increases. When the tensioning roll 222 descends and is detected by the lower limit position detection sensor 224, the payout amount of the yarn supply motor connected to the yarn supplier 11 decreases, and the feed amount of the fiber bundle Tm decreases.

In this way, the feed rate of the fiber bundle Tm is adjusted so that the tension-applying roll 222 is positioned within a predetermined range based on the detection signals from the upper limit position detection sensor 223 and the lower limit position detection sensor 224, and the tension of the fiber bundle Tm is stabilized by the weight of the tension-applying roll 222. The tension applied to the fiber bundle Tm can be appropriately determined by adjusting the weight of the tension-applying roll 222.

A vibration elimination section 23 is provided downstream of the tension applying section 22 in the conveying direction as a mechanism for reducing vibrations occurring in the fiber bundle Tm. The vibration elimination section 23 is provided with a pair of support rolls 231 and an oscillating roll 232. The oscillating roll 232 is arranged between the pair of support rolls 231, and is set so that the fiber bundle Tm passing below the support roll 231 passes above the oscillating roll 232. A spring member 233 is provided to bias the oscillating roll 232 to move upward, and the oscillating roll 232 is biased upward. This configuration reduces vibrations occurring in the fiber bundle Tm.

Downstream of the vibration removal section 23 in the conveying direction, a reverse-back prevention section 24 is provided to prevent the conveyance of the fiber bundle Tm from reversing. The reverse-back prevention section 24 is composed of a unidirectional rotating roll 241 and a support roll 242. The unidirectional rotating roll 241 is fitted with a one-way clutch (not shown) so that it rotates only in the direction in which the fiber bundle Tm is conveyed and does not rotate in the direction in which it is pulled back. The fiber bundle Tm is nipped and conveyed by the unidirectional rotating roll 241 and the support roll 242 to prevent the fiber bundle Tm from traveling in the reverse direction.

The fiber bundles Tm unwound from each yarn supplier 11 are given a predetermined tension, sent out through the vibration elimination section 23 and the reverse return prevention section 24, and transported by the guide roll 25 toward the alignment roll 26. The alignment roll 26 aligns the multiple transported fiber bundles Tm so that they are arranged at equal intervals on the same plane, and discharges the multiple fiber bundles Tm.

The fiber bundle Tm, which is set to a predetermined range of tension, passes through the fiber spread processing section 3 installed in the conveying direction D. The fiber spread processing section supports the fiber bundle Tm with a pair of guide rolls 31 arranged in the conveying direction D. Between the guide rolls 31, an air cavity tube 32 is provided, and the upper opening of the air cavity tube 32 is formed at a predetermined length between the guide rolls 31. A flow rate adjustment valve 33 and an intake pump 34 are attached to the lower side of the air cavity tube 32. By operating the intake pump 34 to suck air from the air cavity tube 32, a downward air current due to suction is generated at the upper opening between the guide rolls 31. In the present invention, the downward air current due to suction is called an intake air current. The flow rate of the intake air current can be adjusted by adjusting the flow rate adjustment valve 33.

When the suction airflow passes over the fiber bundle Tm being transported between the guide rolls 31 and the fiber bundle Tm becomes bent in the direction of the airflow, the air passes between the fibers of the bent fiber bundle Tm, exerting a force that moves the fibers in the width direction of the fiber bundle Tm, and the fiber bundle Tm is opened. This opening action is well known. In this example, the opening process is performed using an air flow, but the opening process can also be performed using a liquid such as water as the fluid.

The deflection forming section 4 is disposed between a pair of guide rolls 31 in the fiber spreading section 3. In this example, the deflection forming section 4 is configured as shown in the explanatory diagram in FIG. 2. It is composed of a deflection forming member 41 that rotates to give the fiber bundle Tm a tensioned state and a relaxed state, a support rod 43 that is disposed along a central axis O set in the longitudinal direction of the deflection forming member, and a rotary motor 44 that rotates the deflection forming member 41 around the central axis O.

The rotating deflection forming member 41 in FIG. 2 is formed as a plate-like body having a predetermined thickness, and its length in the longitudinal direction is set to be longer than the length that allows contact across the entire width of the multiple spread fiber bundles Tm. A pair of contact surfaces 41a are formed on both side edges that are set parallel to the central axis O set in the longitudinal direction and at a predetermined distance. Since the contact surface 41a is the surface that comes into contact with the fiber bundles Tm, it is formed into a curved shape on the cut surface in the direction perpendicular to the central axis O. The curved shape makes it possible to prevent damage to the fiber bundles that it comes into contact with. Specifically, it is desirable for the cross-sectional shape to be an arc shape, etc.

The deflection forming member 41 is provided with an opening M through which the suction airflow passes. In the rotating deflection forming member 41 in FIG. 2, the opening M opens in the thickness direction of the plate-like body, and the opening width is set to a predetermined width that allows the passage of fluid within a range in which the fiber bundles Tm can be spread symmetrically about the central axis O, and the opening length is set to be longer than the length over which the suction airflow acts across the entire width of the multiple spread fiber bundles Tm.

Figure 3 shows a schematic diagram of the opening state of multiple fiber bundles by a rotating deflection forming member. The deflection forming member 41 is arranged on the opposite side of the guide roll 31 with respect to the fiber bundle Tm being conveyed, and is set to a length that allows contact across the entire width of the multiple fiber bundles Tm being opened. The deflection forming member 41 rotates by the rotation drive of the rotation motor 44, and the contact surface 41a of the deflection forming member 41 moves in a direction inclined to the conveying direction D while alternately contacting the fiber bundle Tm, rotating to stroke the surface of the fiber bundle Tm and pushing the fiber bundle Tm between the guide rolls 31 to make it tense. The contact surface 41a further rotates upward, and the fiber bundle Tm enters a temporarily relaxed state at the moment when the contact surface 41a separates from the tense fiber bundle Tm.

In FIG. 3, the deflection forming member 41 is attached to a pair of wall surfaces arranged on the width direction side of the fiber bundle Tm of the cavity tube 32. In this case, a disk-shaped wall member 42 is attached to both longitudinal ends of the deflection forming member 41, and a circular opening is provided in the wall surface so that the wall member 42 fits within the wall surface of the cavity tube 32. A ball bearing or the like is arranged between the opening in the wall surface and the outer periphery of the wall member 42, so that the deflection forming member 41 can rotate.

After the contact surface 41a of the deflection forming member 41 pushes the fiber bundle Tm between the pair of guide rolls 31, it rotates to separate from the fiber bundle Tm. Immediately afterwards, the air flow (suction airflow) sucked into the air cavity tube 32 from the opening M of the deflection forming member 41 acts directly on the fiber bundle, causing the fiber bundle Tm to bend in a curved shape in the direction of the suction airflow. At the same time, air passes between each fiber, spreading the fibers in the width direction with good dispersion.

In a method in which a fiber bundle is spread while bending in a curved shape by passing a fluid between each fiber, when the fiber bundle is bent in the direction of the fluid flow, the fibers can be moved in the width direction most efficiently by passing the fluid through the area adjacent to the position downstream in the flow direction where the bundle is most bent (hereinafter referred to as the "maximum bending area"), and spreading with good fiber distribution can be achieved.

Figure 4 is an explanatory diagram of the air flow when a rotating deflection forming member 41 with an opening M is placed at approximately the center between the guide rolls 31. By providing the opening M in the deflection forming member 41, immediately after the contact surface 41a of the deflection forming member 41 separates from the fiber bundle Tm, the air that has passed through the opening flows directly into and passes through the maximum deflection region N of the fiber bundle Tm, which allows for efficient fiber spreading. In this case, the area near the position where the deflection forming member 41 pushes the fiber bundle Tm to the maximum (maximum pushing position P) becomes the maximum deflection region N when the fiber bundle Tm is curved in the direction of the fluid flow.

Figure 10 is an explanatory diagram of fiber spreading when a rotating contact member according to a conventional example is used. In the conventional example, a fluctuation imparting section 8 is provided between guide rolls 31 arranged at the upper opening of the cavity tube 32 of the fiber spreading processing section 3. The fluctuation imparting section 8 corresponds to the deflection forming section 4 of the present invention. The contact member 81, which corresponds to the deflection forming member 41 of the present invention, alternately pushes the fiber bundle Tm into the cavity tube 32 to make it tense, and moves it away from the fiber bundle Tm to make it relaxed. Since the contact member 81 in the conventional example has a solid plate-like structure, after the contact surface 81a of the contact member 81 moves away from the fiber bundle Tm, the suction airflow flows around the contact member 81 and flows in, and it is considered that the suction airflow does not efficiently pass through the maximum deflection region of the fiber bundle Tm for fiber spreading.

In addition, in the conventional example, the area through which the suction airflow passes at the upper opening of the cavity tube 32 when the contact surface 81a of the contact member 81 pushes the fiber bundle Tm to the most downstream side varies greatly from the area through which the suction airflow passes at the upper opening when the contact surface 81a separates from the fiber bundle Tm and becomes approximately parallel to the conveying direction D. It is believed that the large variation in the area causes the flow of fluid to vary greatly, which is also a cause of vibrations occurring throughout the entire fiber-spreading processing section. In particular, it is believed that the vibrations become greater as the fiber-spreading processing speed increases, since the area width changes in a short period of time.

As can be seen from the explanatory diagram of FIG. 4, in the present invention, by providing an opening M in the deflection forming member 41, the difference in area between the area through which the suction airflow passes at the upper opening of the cavity tube 32 when the contact surface 41a of the deflection forming member 41 pushes the fiber bundle Tm to the most downstream side and the area through which the suction airflow passes at the upper opening when the contact surface 41a separates from the fiber bundle Tm and becomes approximately parallel to the conveying direction D is smaller than in the conventional example. Therefore, compared to the conventional example, vibrations and noise generated in the entire fiber spreading processing section are reduced, and stable fiber spreading can be performed even at high speed processing.

The rotating deflection forming member 41 in FIG. 2 has an opening M of a predetermined width and length in the thickness direction of a plate-like body having a predetermined thickness, and the opening is formed by drilling or the like. The deflection forming member 41 only needs to have an opening formed in the maximum deflection area during rotation through which airflow can pass, and the shape of the opening is not particularly limited. For example, the deflection forming member can be formed by combining multiple members to form the opening. In FIG. 5, it is composed of two pushing members 411 and two mounting members 412.

The pushing member 411 is a member that pushes the fiber bundle Tm in a direction perpendicular to the conveying direction. The cross-sectional shape in the direction perpendicular to the central axis O is approximately rectangular, and the contact surface 41a that comes into contact with the fiber bundle Tm is curved so as not to damage the fiber bundle. The mounting member 411 is disk-shaped with a predetermined thickness, and has holes that allow the pushing member 411 to be fixed.

Two pushing members 411 are arranged at positions symmetrical about the central axis O, and both ends of the pushing members 411 are fitted and fixed into the respective mounting members 412. Then, by fitting the pushing members 411 into the mounting members 412 at a fixed distance from the central axis O, a specified gap is created between the two pushing members, and this gap is formed as an opening M. The length of the pushing members along the central axis O is set to be equal to or greater than the length that allows contact over the entire width of the multiple spread fiber bundles Tm.

A support rod 43 is attached to the center of one of the disk-shaped mounting members 412 and connected to a rotary motor 44, while the other disk-shaped mounting member 412 is attached so that it fits inside a circular opening provided in the wall of the cavity tube. A ball bearing or the like is placed between the opening in the wall and the outer periphery of the mounting member 412. With this configuration, the deflection forming member 41 can rotate at the upper opening of the cavity tube.

The shape of the pushing member 411 may be a roll shape or an ellipse shape in the cross section perpendicular to the central axis O. It is sufficient that the surface in contact with the fiber bundle Tm is curved. The number of pushing members 411 may be more than two. By arranging multiple pushing members so that the tips of the contact surfaces 41a of the pushing members 411 are equally spaced on one circumference, the rotation of the deflection forming member 41 is stabilized and the deflection of the fiber bundle Tm is also stably formed, which is desirable. As a result of the study by the inventors, it is desirable to have up to four pushing members 411. If the number of pushing members 411 is more than that, the pushing members 411 will not separate from the fiber bundle Tm, or even if they do separate, it will be instantaneous, and the fiber bundle will not be deflected, and wide spreading will not be possible.

Figure 6 is a schematic diagram of a deflection forming member that vibrates vertically in a direction intersecting the conveying direction of the fiber bundle according to the present invention. In the present invention, a deflection forming member with an opening M for efficiently spreading the fiber bundle is placed at the upper opening of the air cavity tube. The deflection forming member can be rotated to give tension and relaxation to the fiber bundle, or the deflection forming member can be vibrated up and down to give tension and relaxation to the fiber bundle.

The deflection forming member 41 in FIG. 6 causes deflection in the multiple fiber bundles by vibrating it up and down in the conveying direction of the fiber bundle. The deflection forming member 41 has a cross-sectional shape in a direction perpendicular to the central axis O that is, for example, semicircular as shown in FIG. 6, and the curved surface portion is the portion that comes into contact with the fiber bundle. The opening M is set in a direction in which the suction airflow can pass, with a predetermined width that allows the suction airflow to pass through within a range in which the fiber bundles can be spread symmetrically about the central axis O, and with a predetermined length that allows the suction airflow to act over the entire width of the multiple spread fiber bundles.

The deflection forming member 41 in FIG. 6 has a support rod 43 protruding along the central axis O, and one of the support rods 43 is connected to a lifting rod 453, a connecting rod 452, and a rotating plate 451. When the rotating plate 451 rotates by receiving a rotational drive from the rotating motor 44, the connecting rod 452 and the lifting rod 453 form a crank mechanism to move the support rod up and down. The other support rod 43 is attached to the wall of the air cavity tube with a mechanism such as a linear slide that allows the support rod to move up and down smoothly. With this configuration, the deflection forming member 41 can move up and down quickly and smoothly.

The deflection forming member 41 in FIG. 6 is placed at the upper opening of the air cavity tube, and the deflection forming member 41 is vibrated up and down taking into account the transport speed of the fiber bundle, so that the fiber bundle is deflected immediately after the deflection forming member 41 separates from the fiber bundle. At this time, the fluid that passes through the opening M provided in the deflection forming member 41 acts on the maximum deflection area of the deflected fiber bundle, opening the fiber bundle.

Figure 7 is an explanatory diagram of the length of the section in which the fiber bundle according to the present invention is deflected and the length of the section through which the fluid acts on and passes through the fiber bundle. In the present invention, a deflection forming member 41 is disposed between a pair of guide rolls 31 to push the fiber bundle Tm in a direction perpendicular to the conveying direction D, so that the length of the fiber bundle Tm conveyed between the pair of guide rolls 31 is equal to or greater than the linear distance between the guide rolls 31. Therefore, when the fiber bundle Tm separates from the deflection forming member 41, it can bend between the guide rolls 31 in the direction in which the fluid passes.

In the method of passing a fluid through a fiber bundle to bend it into a curved shape and spread it, efficient spreading can be achieved by applying the fluid to the maximum deflection area of the bent fiber bundle and passing it through. Therefore, it is desirable to apply the fluid to an area centered on the nearby area and pass it between each fiber. In the present invention, an opening is provided in the deflection forming member 41, so that the fluid that passes through the opening can flow directly into the nearby area and pass between the fibers, enabling efficient spreading.

In a fiber bundle that is bent between a pair of guide rolls 31, the length of the linear section from the point where the fiber bundle leaves contact with the guide roll 31 to the point where the fiber bundle comes into contact with the other guide roll 31 is defined as the bending section length L, and the length in the conveying direction D of the area where the fluid acts on the fiber bundle Tm and passes between each fiber is defined as the fluid action section length W. In this invention, since the opening M is provided in the bending forming member 41, it is possible to set L>W, and the fluid can be passed through the maximum bending area of the fiber bundle that is bent in the fluid passing direction, and efficient fiber spreading can be performed. Since it is possible to narrow the fluid action section length W, the amount of fluid consumed can be reduced, and therefore the effect of reducing energy consumption can be obtained. Furthermore, by reducing the amount of fluid sucked into the air cavity tube, there is also the effect of reducing vibration of the entire fiber spreading processing section.

In FIG. 1, the fiber bundle Tm is subjected to repeated fluctuations by the deflection forming member 41 and is subjected to the action of the fluid passing through the opening M formed in the deflection forming member 41, and is deflected while being efficiently opened. At this time, the fiber bundle Tm is composed of multiple fibers bundled together by a sizing agent, etc., but if a sizing agent with high bundling properties is used as the sizing agent, or if the amount of sizing agent attached is large, the bundling properties of the fibers become strong and the fibers become difficult to separate. In such a case, it is recommended to heat the fiber bundle Tm by blowing hot air onto the fiber bundle Tm using the heating unit 5. The sizing agent softens when heated, making it easier for the fibers to separate. The heating temperature depends on the type and amount of sizing agent, and the conveying speed of the fiber bundle Tm, and it is recommended to find and set a temperature at which the sizing agent used is softened and the fiber bundle is easy to open. The inventors set the non-ambient temperature to a range of 60 degrees to 120 degrees.

The fiber bundle Tm that has passed through the fiber spreading processing section 3 is processed into a spread fiber yarn Ts that has been spread with good fiber distribution. In FIG. 1, a plurality of spread fiber yarns Ts are clamped and transported by a pair of take-up rolls 61 in the take-up section 6. The take-up rolls 61 are rotated by a take-up motor (not shown in FIG. 1) to transport the spread fiber yarns Ts. The plurality of spread fiber yarns Ts that have been transported by the take-up rolls 61 are wound up by a winding device (not shown) or are directly transported to a resin impregnation device or the like and processed into a prepreg sheet. Note that a prepreg sheet manufacturing device that manufactures prepreg sheets is usually configured with a mechanism for transporting the sheet, and in this case, the take-up section 6 in FIG. 1 is not provided.

8 and 9 are schematic plan and side views of a fiber-spreading device according to another embodiment of the present invention. In this fiber-spreading device, fiber-spreading processing sections 3 are arranged at three locations along the conveying path of the fiber bundle Tm. A heating section 5 is provided corresponding to each fiber-spreading processing section 3, and the spread width of each fiber-spreading processing section 3 is set to be gradually wider from the upstream side to the downstream side in the conveying direction. A rotating deflection forming member 41 having an opening M is arranged at the upper opening of each fiber-spreading processing section 3. A support rod 43 is attached to one side of the deflection forming member 41, and a drive pulley 46 is fixed to each support rod 43, and each drive pulley 46 is connected to a rotary motor 44 via a drive transmission belt 47. By rotating and driving the rotary motor 44, each drive pulley 46 rotates and the deflection forming members 41 rotate in synchronization with each other. In this embodiment, three fiber-spreading processing sections are provided, but there may be two or four or more fiber-spreading processing sections, and the number of sections to be used can be determined based on the fiber bundles to be used, the width to be spread, the conveying speed, etc.

In the above-mentioned example of the fiber spreading device, a drive transmission belt is used, but a drive transmission chain may also be used. In addition, although multiple deflection forming members 41 are rotated synchronously, the timing of rotation of the deflection forming members 41 can easily be varied, and it is desirable to adjust the rotation timing according to the characteristics of the fiber bundle, such as the type, fineness, and number of fibers, and the spread width, and perform the fluctuating operation at the optimal timing.

The deflection forming members 41 synchronously push the fiber bundle Tm in a direction intersecting the conveying direction to place it in a tensed state, and then the deflection forming members 41 move away from the tensed fiber bundle Tm to place it in a relaxed state. This repeats the fluctuating operation, allowing the fiber bundle Tm to bend in the direction of the fluid flow in the air cavity tube of each fiber-spreading processing unit 3. Since the deflection forming members 41 have an opening M, the suction airflow that passes through the opening acts on the area near the most downstream side of the deflected fiber bundle, and the fluid passes between the fibers, allowing for wide fiber-spreading with good fiber distribution.

The width of the spread of each fiber bundle Tm can be restricted by providing a width restriction guide 48 on the deflection forming member 41. In the embodiment of Figures 8 and 9, three fiber spreading processing sections are arranged, but the most upstream deflection forming member 41 is provided with a wide width restriction guide 48, the next deflection forming member 41 is provided with a narrow width restriction guide 48, and the last deflection forming member 48 is provided with no width restriction guide. With this configuration, wider fiber spreading can be performed in sequence starting from the fiber spreading processing section 3 located upstream in the conveying direction.

The width restriction guide may be a disk-shaped plate that is directly inserted into the deflection forming guide 41 as shown in FIG. 8, or the upper opening of the cavity tube may be formed into a rectangular shape and the side wall may be used as is. Also, multiple wires or the like may be erected inside the cavity tube and used as width restriction guides.

On the downstream side of the fiber-spreading processing section 3 in the conveying direction, a width direction variation imparting section 7 that slides in the width direction against the spread yarn Ts formed by spreading each fiber bundle is provided. The width direction variation imparting section 7 has a horizontal vibration roll 71 arranged over the entire width above the multiple spread yarns Ts, and a support roll 72 is arranged below the multiple spread yarns Ts. The horizontal vibration roll 71 is connected to a crank mechanism 74, and the crank mechanism 74 is driven by a crank motor 73 to move the horizontal vibration roll 71 back and forth in the width direction of the multiple spread yarns Ts. The horizontal vibration roll 71 moves back and forth to slide in contact with the fibers of the multiple spread yarns Ts, softly loosening the portions where the fibers are attached to each other and filling the gaps between the fibers by moving the fibers laterally, and the multiple spread yarns Ts are finished into a sheet state in which the fibers are uniformly distributed, to form a spread fiber sheet S.

The spread fiber sheet S is clamped and transported by the take-up roll 61. The take-up roll 61 is rotated and driven by a rotary motor 62 to transport the spread fiber sheet S. The spread fiber sheet S delivered by the take-up roll 61 is wound up by a winding device (not shown) or is directly delivered to a resin impregnation device or the like and processed into a prepreg sheet.

Example 1
The experiment was carried out with a device configuration that had one set of a fiber spreading section such as the fiber spreading device shown in Figure 1 and a deflection forming section using a rotating deflection forming member. A carbon fiber bundle (manufactured by Toray Industries, Inc., product number T700SC-60E-12K, fiber diameter approximately 7 μm, number of fibers 12,000) was used as the fiber bundle. The original width of the fiber bundle was approximately 6 mm.

The dimensions of each member in the device in the fiber-spreading section and the bend forming section shown in Figs. 11A and 11B were set as follows.
Deflection forming member 41: width X1 = 48 mm, thickness X2 = 20 mm
Contact surface 41a: cross-sectional shape curvature radius X3 = 10 mm
Opening width at opening M: X4 = 20 mm
Guide roll 31; outer diameter X5 = 20 mm
Cavity tube 32: length in the conveying direction, i.e., length of the fluid action section X6 = 52 mm
Height difference X7 between the central axis O of the deflection forming member 41 and the uppermost point of the guide roll 31 = 2 mm
Distance X8 between the central axis O of the deflection forming member 41 and the central axis of the guide roll 31 = 36 mm
Distance X9 between the central axes of the guide rolls 31 = 72 mm
The height difference X10 between the lowest point of the contact surface 41a during rotation and the highest point of the guide roll 31 is 22 mm.

The heating temperature by the heating mechanism 5 was set to approximately 80°C near where the blown hot air hit the fiber bundle, and the flow rate of the suction airflow of the air cavity tube 32 was 20 m/sec when there was no fiber bundle. The number of fiber bundles transported to the fiber opening processing section 3 was eight, and they were transported at intervals of 25 mm in the width direction. The initial tension of the fiber bundle was set to 150 g, and the transport speed was set to 15 m/min and 40 m/min. The rotation speed of the deflection forming member 41 was set to 250 rpm when the transport speed was 15 m/min and 450 rpm when the transport speed was 40 m/min, and the fluctuating operation was performed 500 times and 900 times per minute, respectively.

The state of the fibers being spread during the spreading process was visually confirmed after passing through the fiber spreading section. The vibration of the device during the spreading process was also confirmed as follows.

A miniature accelerometer (model NP-3211, manufactured by Ono Sokki Co., Ltd.) was attached to the bottom of the cavity tube 32, and the miniature accelerometer was connected to a sensor amplifier (model PS-1300, manufactured by Ono Sokki Co., Ltd.). The output data from the sensor amplifier was then input to a personal computer, where the relationship between time and acceleration was plotted in a graph to confirm the vibration of the device during fiber spreading.

When the fiber-spreading process was performed as described above, the fiber bundles were processed into a spread fiber with a uniform distribution in a width of 25 mm at both the processing speed of 15 m/min and 40 m/min, and a spread fiber sheet with a width of 200 mm was also able to be finished. As for the continuity of the fiber-spreading, the fiber-spreading could be performed stably for 10 minutes or more without generating large gaps between the spread fiber bundles.

Regarding the vibration state of the fiber-spreading device, Fig. 12A shows the results at a processing speed of 15 m/min, and Fig. ^12B shows the results at a processing speed of 40 m/min. The fiber-spreading process was carried out for more than 10 minutes, and the results for 30 seconds are shown. At a processing speed of 15 m/min, the acceleration was 50 m/s2 or less, and at a processing speed of 40 m/min, the acceleration was 75 m/s2 or ^less . In both cases, the vibration was stable and no irregular vibration was generated.

Comparative Example

<Comparative Example 1>
The experiment was carried out with a fiber spreading device having a configuration similar to that shown in Fig. 1, with one fiber spreading section and a rotating contact member that gives a deflection to the fiber bundle within the fiber spreading section. As in Example 1, a carbon fiber bundle (manufactured by Toray Industries, Inc., product number T700SC-60E-12K, fiber diameter about 7 μm, number of fibers 12,000) was used as the fiber bundle. The original width of the fiber bundle was about 6 mm.

The device configuration of the fiber opening processing section and the contact member was the same as in Example 1, and a solid member without openings of the deflection forming member of Example 1 was used as the contact member. All dimensions were the same as in Example 1.

The heating mechanism for heating the fiber bundle was the same as in Example 1. The number of fibers to be conveyed, the flow rate of the suction air flowing into the cavity tube, the set spread width, the initial tension of the fiber bundle, and the rotation speed of the contact member corresponding to the processing speed were also the same as in Example 1. The conveying speed was also set to 15 m/min and 40 m/min, as in Example 1.

The state of the fibers being spread during the spreading process was visually confirmed after passing through the fiber spreading section. As in Example 1, the vibration of the device during the spreading process was also measured using a miniature accelerometer attached to the bottom of the wind tunnel tube. The relationship between time and acceleration was then plotted in a graph to confirm the vibration of the device during the spreading process.

When the prior art spreading process was carried out as described above, a spread fiber in which each fiber bundle was dispersed to a width of 25 mm was obtained at processing speeds of 15 m/min and 40 m/min. Under the processing conditions used this time, gaps were observed in the fiber bundles at a conveying speed of 40 m/min. When the conveying speed was 40 m/min, the contact member rotation speed was set to 550 rpm and fluctuating operations were performed 1,100 times per minute, resulting in a spread fiber sheet with good fiber distribution and a width of 200 mm.

Figure 13A shows the vibration state of the fiber-spreading device at a processing speed of 15 m/min, and Figure 13B shows the results at a processing speed of 40 m/min. Fiber-spreading was performed for more than 10 minutes, and the results for 30 seconds are shown. At processing speeds of 15 m/min and 40 m/min, the acceleration was greater than in Example 1, indicating that the device vibration was greater. When a contact member is used, when the contact member is nearly parallel to the transport direction of the fiber bundle, the area through which the suction airflow can pass through the cavity tube is very narrow. It is believed that the large change in the area through which the suction airflow can pass also increases the vibration generated in the cavity tube.

From the examples and comparative examples, it was found that the present invention allows the suction airflow that passes through the openings in the deflection forming member to flow directly through the maximum deflection area of the fiber bundle, thereby enabling efficient fiber spreading. It was also confirmed that the vibration frequency during the fiber spreading process is reduced for devices such as air tunnel tubes, and it is expected that the durability of the device will improve.

1... Yarn supplying section, 11... Yarn supply body, 12... Yarn supplying motor, 2... Guide section, 21... Guide roll, 22... Tensioning section, 221... Support roll, 222... Tensioning roll, 223... Upper limit position detection sensor, 224... Lower limit position detection sensor, 23... Vibration elimination section, 231... Support roll, 232... Oscillating roll, 233... Spring member, 24... Reverse return prevention section, 241... One-way rotation roll, 242... Support roll, 25... Guide roll, 26... Alignment roll, 3... Fiber opening processing section, 31... Guide roll, 32...air cavity tube, 33...flow rate control valve, 34...suction pump, 4...deflection forming section, 41...deflection forming member, 41a...contact surface, 411...pushing member, 412...mounting member, 42...wall member, 43...support rod, 44...rotation motor, 45...crank mechanism, 451...rotating plate, 452...connecting rod, 453...lifting rod, 46...driving pulley, 47...drive transmission belt, 48...width regulating guide, 5...heating section, 6...take-up section, 61...take-up roll, 62: Rotation motor, 7: Width direction fluctuation imparting section, 71: Lateral vibration roll, 72: Support roll, 73: Crank motor, 74: Crank mechanism, 8: Fluctuation imparting section, 81: Contact member, 81a: Contact surface, Tm: Fiber bundle, Ts: Spread yarn, S: Spread yarn sheet, O: Central axis, M: Opening, P: Maximum push-in position, N: Maximum deflection region, L: Deflection section length, W: Fluid action section length, D: Feed direction, X1: Width of deflection forming member 41, X2: Thickness of deflection forming member 41 , X3: radius of curvature of the cross-sectional shape of the contact surface 41a, X4: opening width at the opening of the deflection forming member 41, X5: diameter of the guide roll 31, X6: length of the air cavity tube 32 in the conveying direction, i.e., length of the fluid action section, X7: height difference between the central axis O of the deflection forming member 41 and the uppermost point of the guide roll 31, X8: distance between the central axis O of the deflection forming member 41 and the central axis of the guide roll 31, X9: distance between the central axes of the guide rolls 31, X10: height difference between the lowest point of the contact surface 41a when rotating and the highest point of the guide roll 31

Claims (10)

A fiber-spreading method in which a fiber bundle formed by aligning and bundling a large number of fibers is pulled out from a yarn supplier and conveyed, a deflection-forming member is brought into contact with a portion of the fiber bundle and pushed in a direction intersecting the conveying direction to place it in a tensed state, and then the deflection-forming member is moved away from the tensed fiber bundle to place the fiber bundle in a relaxed state, and in a region where a fluctuating operation is repeatedly performed, a fluid is passed through the fiber bundle, and the fibers are moved in the width direction while being deflected in the direction of fluid passage, to be opened in the fiber-spreading method, in which an opening is formed in the deflection-forming member through which the fluid passes, and the fluid that has passed through the opening passes through a region near the maximum push-in position of the fiber bundle due to the operation of the deflection-forming member, and the fibers are moved in the width direction while being deflected in the direction of fluid passage, to be opened. The fiber bundle spreading method according to claim 1, in which the deflection forming member rotates to repeatedly apply fluctuating tension and relaxation to the fiber bundle. The fiber bundle spreading method according to claim 1, in which the deflection forming member vibrates in a direction intersecting the conveying direction of the fiber bundle, repeatedly applying fluctuating tension and relaxation to the fiber bundle. The fiber bundle spreading method according to claim 1, wherein the relationship between the bending section length, which is the length in the conveying direction of the region where the fiber bundle bends, and the fluid action section length, which is the length in the conveying direction of the region where a fluid acts on and passes through the bent fiber bundle, is such that the bending section length is greater than the fluid action section length. The fiber bundle spreading method according to claim 1, in which a region in which a fluid is applied to the fiber bundle being transported to bend the fibers and move them in the width direction to spread them is set at a plurality of locations on the transport path of the fiber bundle. The fiber bundle spreading method according to claim 5, in which the deflection forming member is provided with a width restriction guide that restricts the spread width of the fiber bundle being conveyed, and the fiber bundle is spread while gradually expanding its spread width. The fiber bundle spreading method according to claim 1, in which a plurality of the fiber bundles are arranged in the width direction and conveyed, and each of the fiber bundles is spread. A fiber-spreading device that includes a fiber-spreading section that applies a fluid to the fiber bundle being conveyed to bend the fibers and move them in the width direction to spread them out, and a deflection forming section that arranges a deflection forming member with an opening through which the fluid passes within the fiber-spreading section, and that repeatedly performs a fluctuating operation in which the deflection forming member pushes the fiber bundle in a direction intersecting the conveying direction to make it tense, and then separates the deflection forming member from the fiber bundle in the tense state to make it relax. The fiber bundle spreading device according to claim 8, wherein the deflection forming member comprises a plurality of pushing members that push the transported fiber bundle in a direction intersecting the transport direction, and a mounting member that is attached to the pushing members so as to form the openings at intervals that allow the fluid to pass through the pushing members. The fiber bundle spreading device according to claim 9, wherein the pushing member is formed in a roll shape.

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