JP2019059808A - Fiber reinforced resin tubular body - Google Patents

Abstract

To provide a fiber reinforced resin tubular body of which reinforced fiber forming a flexure planned area is hardly broken and the flexure planned area is hardly buckled when flexure processing is conducted at a state that a resin at the flexure planned area can be plastically deformed by heating.SOLUTION: A fiber reinforced thermoplastic resin forming a fiber reinforced resin tubular body 1 is formed by a continuous carbon fiber S and a polyamide resin, and has an arrangement structure of the continuous carbon fiber so that orientation angle θ1 to an axis line G of the continuous carbon fiber S forming a flexure planned area VE is larger than orientation angle θ2 to the axis line G of the continuous carbon fiber S respectively forming areas E1, E2 which are other than the flexure planned area.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fiber-reinforced resin tubular body formed of a fiber-reinforced resin.

  Conventionally, as a fiber reinforced resin tubular body of this type, an FRP cylindrical body manufactured by winding a fiber reinforced resin around a mandrel is known (Patent Document 1). The FRP cylinder has a winding angle A of ± 80 to 90 ° at both axial ends of the reinforcing fiber pipe, a winding angle B at the central portion of ± 5 to 20 °, and a winding angle between both ends and the central portion Are set to the winding angle C which gradually changes from the winding angle A to the winding angle B.

JP-A-8-99373

  However, since the FRP cylinder described in Patent Document 1 described above has high bending strength in the area other than the end, when bending is performed in a state where plastic deformation is possible by heating the resin in the area to be bent, There is a problem that the reinforcing fiber forming the bending expected area is broken and the bending expected area is easily buckled.

  Therefore, the present invention is created to solve the above-mentioned problems, and when the resin in the area to be bent is bent in a state where plastic deformation is possible by heating, the area to be bent is formed. It is an object of the present invention to provide a fiber-reinforced resin tubular body in which reinforcing fibers are less likely to break and in which a region to be bent is less likely to buckle.

In order to achieve the above-mentioned object, the fiber-reinforced resin tubular body according to the present invention is formed of a fiber-reinforced thermoplastic resin, and is bent in a state where the thermoplastic resin in the area to be bent can be plastically deformed by heating. A fiber-reinforced resin tubular body capable of bending a predetermined area, and the arrangement structure of reinforcing fibers in the predetermined bending area is easier to displace relative to bending than the area other than the predetermined bending area between the reinforcing fibers. The first feature is the arrangement structure.
The above-mentioned "relative displacement between reinforcing fibers is easily caused" means that the reinforcing fibers are easily moved (slippery) in the thermoplastic resin in which plastic deformation is possible by heating.

The fiber-reinforced resin tubular body having the above first feature is a fiber-reinforced resin tubular body which enables bending of the planned bending region in a state where plastic deformation of the thermoplastic resin in the planned bending region becomes possible by heating. Thus, the area to be bent is more likely to be displaced relative to the bending process relative to the area other than the area to be bent.
That is, among the thermoplastic resins which can be plastically deformed by heating, the reinforcing fibers in the planned bending region are relatively easy to be displaced due to the bending load at the time of bending, and are not easily broken. Is hard to buckle.

  Further, in the fiber-reinforced resin tubular body according to the present invention, in the first feature described above, the fiber-reinforced thermoplastic resin is at least formed of a continuous reinforcing fiber and a thermoplastic resin, and the arrangement structure is the fiber-reinforced resin. A second feature is that the orientation structure of the continuous reinforcing fiber with respect to the axis of the resin tubular body is a configuration in which the area to be bent is larger than the area other than the area to be bent.

The fiber-reinforced resin tubular body having the second feature has an arrangement structure in which the orientation angle of the continuous reinforcing fiber with respect to the axis line is larger in the planned bending region than in the region other than the planned bending region.
For this reason, among the continuous reinforcing fibers forming the planned bending region, among thermoplastic resins which can be plastically deformed by heating, they are relatively easy to be displaced following the bending load at the time of bending, and it is difficult to break. , Bending area is difficult to buckle.

  Further, in the fiber-reinforced resin tubular body according to the present invention, in the first or second feature described above, the fiber-reinforced thermoplastic resin is at least formed of a continuous reinforcing fiber and a thermoplastic resin, and the arrangement structure is A third feature of the present invention is a configuration in which the volume content of the continuous reinforcing fibers is smaller in the planned bending region than in the region other than the planned bending region.

The fiber-reinforced resin tubular body provided with the third feature is an arrangement structure in which the volume fraction of continuous reinforcing fibers is smaller in the planned bending region than in the region other than the planned bending region.
For this reason, among the thermoplastic resins which can be plastically deformed by heating, the continuous reinforcing fibers forming the planned bending region interfere with each other when the relative displacement is performed following the bending load at the time of bending. Because there are less continuous reinforcing fibers (that hinder the relative displacement) than the area other than the area to be bent, relative displacement is likely to occur and breakage is difficult.
Therefore, it is difficult for the region to be bent to buckle.

  Further, in the fiber-reinforced resin tubular body according to the present invention, in the first to third features described above, the disposition structure is a tape formed by weaving reinforcing fibers with a thermoplastic resin. A fourth feature is that the configuration has a spirally wound configuration so as to partially overlap.

The tubular body having the fourth feature is an arrangement structure in which a tape formed by weaving reinforcing fibers with a thermoplastic resin is spirally wound so that a part thereof overlaps. For this reason, when the thermoplastic resin is bent in a state where plastic deformation is possible by heating, between the reinforcing fibers of the tape forming the planned bending region is between the reinforcing fibers forming the region other than the planned bending region. In addition, since the relative displacement is likely to occur and the fracture is unlikely to occur, it is difficult for the region to be bent to buckle.
Moreover, the tape wound in the area to be bent is relatively displaced in the width direction due to the bending load at the time of bending.
At this time, the bending load applied to the tape is greater in the portion of the tape outside in the bending direction that forms the region to be bent than in the portion of the tape inside in the bending direction that forms the region to be bent.
However, since the tape is formed of short reinforcing fibers in the width direction and reinforcing fibers continuous in the winding direction of the tape, in the wound state, the short reinforcing fibers are disposed along the axial direction. become.
Therefore, since the short reinforcing fibers of the tape forming the outside of the bending direction in the bending direction are only displaced following the bending load applied to the tape, it is difficult to break.

  In the fiber-reinforced resin tubular body according to the present invention, a tape formed by weaving reinforcing fibers with a thermoplastic resin with respect to the fiber-reinforced resin tubular body having the second feature described above is a part thereof The fifth feature of the present invention is that it is spirally wound to overlap.

The fiber-reinforced resin tubular body having the fifth feature is a tape formed by weaving reinforcing fibers with a thermoplastic resin with respect to the fiber-reinforced resin tubular body having the second feature described above. It is spirally wound so that parts overlap.
Therefore, the compressive strength of the fiber-reinforced resin tubular body having the second feature described above can be further enhanced.

  In the fiber-reinforced resin tubular body according to the present invention, a tape formed by weaving reinforcing fibers with a thermoplastic resin with respect to the fiber-reinforced resin tubular body having the third feature described above is a part thereof The sixth feature of the present invention is that it is spirally wound so as to overlap each other.

The fiber-reinforced resin tubular body having the sixth feature is a tape formed by weaving reinforcing fibers with a thermoplastic resin with respect to the fiber-reinforced resin tubular body having the third feature described above. It is spirally wound so that parts overlap.
Accordingly, the compressive strength of the fiber-reinforced resin tubular body having the third feature described above can be further enhanced.

  By carrying out the tubular body according to the present invention, when the resin in the planned bending region is bent in a state where plastic deformation is possible by heating, the reinforcing fibers forming the planned bending region are less likely to break, and the planned bending region It is possible to provide a fiber-reinforced resin tubular body which is less likely to buckle.

It is explanatory drawing of the fiber reinforced resin tubular body used for Experiment 1 in 1st Embodiment of this invention, (a) is a front view, (b) is a side view. It is explanatory drawing of the orientation angle of the continuous carbon fiber which forms the fiber reinforced resin tubular body which concerns on 1st Embodiment of this invention, (a) is a front view of the fiber reinforced resin tubular body which continuous carbon fiber was wound, (B), (c) is explanatory drawing of the orientation angle of the continuous reinforcing fiber in a bending plan area | region, (d), (e) is explanatory drawing of the orientation angle of the continuous reinforcing fiber in area | regions other than a bending plan area | region. It is a conceptual diagram of the bending apparatus used in each experiment of this invention. It is a conceptual diagram which shows the state which the bending apparatus shown in FIG. 3 bent-processed the fiber reinforced resin tubular body. It is explanatory drawing of the fiber reinforced resin tubular body which concerns on 3rd Embodiment of this invention, (a) is a front view of a fiber reinforced resin tubular body, (b) is a part of fiber reinforced resin tubular body shown to (a) (C) is an explanatory view of carbon fibers forming the tape shown in (a), and (d) is an explanatory view of a shift width and an overlap width of the tape. It is an explanatory view for explaining displacement of a tape which forms a fiber reinforced resin tubular body shown in Drawing 5 (a), (a) is an explanatory view of a tape before displacement, (b) is an explanation of a tape after displacement. FIG. It is explanatory drawing of the fiber reinforced resin tubular body by which the bending process was carried out, (a) is a top view, (b) is JJ arrow sectional drawing of (a). It is the chart which put together the experimental result.

  The fiber-reinforced resin tubular body in each of the following embodiments is formed of CFRTP (Carbon Fiber Reinforced Thermo Plastics: carbon fiber reinforced thermoplastic resin), and the thermoplastic resin in the region to be bent can be plastically deformed by heating. It is a fiber reinforced resin tubular body which enables bending processing of a bending scheduled area in a fixed state. Further, in the fiber-reinforced resin tubular body in each of the following embodiments, the arrangement of carbon fibers in which the carbon fibers are more easily displaced relative to bending processing in the bending planned area than in the area other than the bending planned area. It has a structure.

First Embodiment
A fiber-reinforced resin tubular body according to a first embodiment of the present invention will be described with reference to the drawings.
The fiber-reinforced resin tubular body of this embodiment is formed of CFRTP, and the orientation angle of the continuous carbon fiber with respect to the axis of the fiber-reinforced resin tubular body is continuous with the planned bending area larger than the area other than the planned bending area. It is characterized by having an arrangement structure of reinforcing fibers.
As shown in FIG. 1, the fiber-reinforced resin tubular body 1 of the present embodiment is formed in a cylindrical shape (hollow pipe shape) having a circular longitudinal cross-sectional shape. The total length of the fiber-reinforced resin tubular body 1 is L, the outer diameter is φ1, and the inner diameter is φ2. In the fiber-reinforced resin tubular body 1, an area to be subjected to bending, that is, an area to be bent VE is set. The point indicated by the symbol C is the center of the bending radius. The bending planned area VE starts from the position where the fiber reinforced resin tubular body 1 has moved L1 from the left end to the right end, and the width thereof is set to L2.

The fiber-reinforced resin tubular body 1 is formed by known filament winding. The filaments used for filament winding in the present embodiment are those in which a plurality of continuous carbon fibers are coated with a thermoplastic resin which is a matrix resin, or those in which continuous carbon fibers and thermoplastic resin fibers are mixed. The tubular body is wound and formed while melting the resin portion of the filament using a heating device provided in the filament winder. As a result, a tubular body made of CFRTP (Carbon Fiber Reinforced Thermo Plastics: carbon fiber reinforced thermoplastic resin) is formed.
Fig.2 (a) is explanatory drawing of the fiber reinforced resin tubular body 1 of this embodiment, However, It is represented typically so that the winding state of a filament may be known. In FIG. 2, reference symbols θ 1 and θ 2 indicate orientation angles of continuous carbon fibers forming the fiber reinforced resin tubular body 1. Here, the orientation angle is the angle of the continuous carbon fiber with respect to the axis G of the fiber-reinforced resin tubular body 1 (the central axis along the longitudinal direction of the fiber-reinforced resin tubular body 1). 2 (b) and 2 (c) show the orientation angle in the planned bending region VE, and FIGS. 2 (d) and 2 (e) show the orientation angles in the regions E1 and E2 other than the planned bending region. When the filament is helically wound on the mandrel, the filament reciprocates both ends along the axis of the mandrel, and the angle (outward path) when winding from the left end to the right end of the mandrel is indicated by θ1 and θ2, and from the right end to the left end The angles of (winding back) when winding toward are indicated by -.theta.1 and -.theta.2. As illustrated, the orientation angle θ1 of continuous carbon fibers wound in the planned bending region VE is larger than the orientation angle θ2 of continuous carbon fibers wound in the regions E1 and E2 other than the planned bending region VE. For example, the orientation angle θ1 is 45 degrees, and the orientation angle θ2 is 20 degrees.

[Experiment 1]
The present inventors conducted experiments to investigate the influence of the orientation angle of continuous carbon fibers on bending.
(Contents of experiment)
In this experiment, a filament in which continuous PAN (polyacrylonitrile) carbon fiber is mixed with polyamide resin fiber was used as the filament forming the fiber reinforced resin tubular body 1. The volume content of the continuous reinforcing fiber and the polyamide resin is 50% respectively. The width of the filaments is 5 to 6 mm and the thickness is 0.3 to 0.4 mm. In addition, a filament winding apparatus manufactured by Asahi Kasei Engineering Corporation was used.
In the filament winding, while the polyamide resin contained in the filament is melted by heating, four layers are wound around the mandrel by helical winding, and the polyamide resin is solidified by natural cooling, and the fiber reinforced resin tubular body 1 is formed.
The fiber-reinforced resin tubular body 1 thus prepared is in the form of a hollow pipe having a total length L of 510 mm, an outer diameter φ1 of 31.0 mm, and an inner diameter φ2 of 27.2 mm. The longitudinal cross-sectional shape of the fiber-reinforced resin tubular body 1 is a true circle, and the flatness is 1. Moreover, it is L1 = 210-220 mm shown to Fig.1 (a), and it is L2 = about 150 mm. Moreover, in order to prevent deformation of the fiber reinforced resin tubular body 1 at the time of bending, the core material (core) was filled in the fiber reinforced resin tubular body 1. In this experiment, a core material made of PEEK (polyether ether ketone) resin, which is a bundle of linear material having a diameter of about 1 mm and a circular longitudinal cross-section, was used as the core material.
In this experiment, a fiber-reinforced resin tubular body (first embodiment (1)) in which the orientation angle of the continuous carbon fiber is 20 degrees in all of the areas E1 and E2 other than the planned bending area VE and the planned bending area A fiber reinforced resin tubular body (first embodiment (2)) in which the orientation angle θ1 in the planned bending area VE is 45 degrees and the orientation angles θ2 in the areas E1 and E2 other than the planned bending area is 20 degrees respectively did.

  Moreover, as a bending apparatus, what was shown in FIG. 3 was used. The bending apparatus 2 includes a mold 3, a fixed clamp 4, a movable clamp 5, and a slide device (not shown). In this experiment, a stretch bend method was used in which the object to be bent was wound around a die and bent. The left end of the fiber-reinforced resin tubular body 1 is held by the fixed clamp 4, and the right end is held by the movable clamp 5. The fixed clamp 4 and the movable clamp 5 are respectively provided on independent slide devices movable back and forth. The radius of curvature of the R portion 3a of the mold 3 is 284 mm. The bending condition of the fiber-reinforced resin tubular body 1 is that the bending angle θ3 (FIG. 7 (a)) is 10 degrees, and the inner bending radius r in the bending direction, that is, the curvature of the bending center C (FIG. 7 (a)) The radius is 300 mm.

  First, the left end of the fiber-reinforced resin tubular body 1 is attached to the fixed clamp 4 and the right end thereof is attached to the moving clamp 5, and the bending scheduled area VE of the fiber-reinforced resin tubular body 1 is heated by a heating device (not shown). Then, after the bending planned area VE reaches 240 ° C. and the polyamide resin forming the bending planned area VE is melted, the slide device is moved forward (in the direction indicated by the arrow F1 in FIG. 3), that is, toward the mold 3 Move it. Then, as shown in FIG. 4, when the fiber-reinforced resin tubular body 1 abuts on the mold 3, the slide device to which the left fixed clamp 4 is attached is stopped. On the other hand, the slide device to which the movable clamp 5 on the right side is attached advances, and a tensile load is applied to the fiber reinforced resin tubular body 1 in the direction shown by the arrow F2, and the bending planned area VE follows the R portion 3a of the mold 3. Turn. In this experiment, a bending load of 3500 N was applied to the right end of the fiber-reinforced resin tubular body 1 via the movable clamp 5 to perform bending. Then, after natural cooling, the fiber reinforced resin tubular body 1 was removed from the fixed clamp 4 and the movable clamp 5.

(Experimental result)
The inventors of the present invention, the outer diameter A in the inward and outward directions of the bending direction of the fiber-reinforced resin tubular body 1 bent by the above-described method, and the outer diameter B in the vertical direction of the bending direction (FIG. 7 (b)) The bending radius r was measured. In addition, the flatness (= B / A) was calculated. In addition, it was examined whether or not wrinkles, buckling and breakage occurred in the bent area. As shown in FIG. 7, the flatness is obtained by cutting the bending center C of the bent region of the fiber-reinforced resin tubular body 1 in the longitudinal direction, and the ratio of the outer diameter A in the inner and outer directions to the outer diameter B in the vertical direction B / A) was calculated as flatness. The flatness of the fiber-reinforced resin tubular body 1 before bending is 1 because the fiber-reinforced resin tubular body 1 is not crushed.
And each experimental result was evaluated based on the result of having examined whether the crooked area was buckling or breaking. That is, when there was no buckling and breakage in the bent region, it was judged that the bending state was good, and a circle was written as a judgment result of the bending property. In addition, when buckling or breakage occurs in a bent area, no bending occurs under a specified tensile load, and bending radius r is 300 mm or more, the determination of bendability is applicable. As a result, it marked x.

As a result, as shown in FIG. 8, the fiber reinforced resin tubular body (1) in which the orientation angle of the continuous carbon fiber is 20 degrees in all of the areas E1, E2 other than the planned bending area VE and the planned bending area Can not be made, and the determination result of bendability is x.
On the other hand, the fiber-reinforced resin tubular body (2) in which the planned bending area VE is 45 degrees and the areas E1 and E2 other than the planned bending area is 20 degrees can be bent along the bending conditions and is seated in the bent area. Since no bending and breakage occurred, the determination result of bendability is ○. In addition, almost no wrinkles occurred in the bent area.

(Discussion)
The present inventors considered the relationship between the orientation angle of the continuous carbon fiber and the bendability based on the above-described experimental results.
When bending the fiber-reinforced resin tubular body 1 of the present embodiment, the planned bending area VE is heated until the planned bending area VE becomes plastically deformable. Specifically, the bending planned area VE is heated until the polyamide resin of the filament wound in the bending planned area VE is in a molten state. For this reason, when the polyamide resin forming the bending expected area VE is in a molten state, the continuous carbon fibers forming the bending expected area VE can move (slip) in the molten polyamide resin. In other words, between the continuous carbon fibers forming the bending intended area VE, relative displacement is possible among the molten polyamide resin. As a result, in the molten polyamide resin, continuous carbon fibers with a large orientation angle tend to move following the bending load during bending, and elongation and shear deformation of the continuous carbon fibers are suppressed to a small extent. It was guessed that it was hard to break. In addition, when bending is performed, the load in the tensile direction for continuous carbon fibers increases outside the planned bending area VE, but the orientation angle of the continuous carbon fibers in the planned bending area VE is large, so the continuous carbon fibers have an orientation angle Since the load can be followed by displacing so as to be smaller, it was inferred that breakage did not occur. In addition, it was presumed that the continuous carbon fiber was likely to be displaced following the load in the same manner as the inside of the bending planned area VE, thus preventing the continuous carbon fiber from breaking, buckling and breaking.
That is, if the orientation angle of the continuous carbon fiber is large, the relative displacement between the continuous carbon fibers is likely to cause relative breakage, and therefore, it is presumed that buckling or breakage is less likely to occur in the planned bending region and wrinkles are less likely to occur. did.

(Conclusion)
The inventors of the present application have found that the arrangement structure of the reinforcing fibers in the planned bending region is more likely to be displaced relative to bending between the reinforcing fibers than in the region other than the planned bending region, from the above-described experimental results and discussion. It was concluded that if a fiber-reinforced resin tubular body having an arrangement structure is produced, it is possible to provide a fiber-reinforced resin tubular body in which buckling and breakage are less likely to occur in a region to be bent.

Second Embodiment
Next, a fiber-reinforced resin tubular body according to a second embodiment of the present invention will be described with reference to the drawings.
The fiber-reinforced resin tubular body according to the present embodiment is formed of CFRTP, and has a continuous reinforcing fiber arrangement structure in which the volume fraction of continuous carbon fibers is smaller in the planned bending area than in the area other than the planned bending area. It is characterized by

[Experiment 2]
The present inventors conducted experiments to investigate the influence of the volume content of continuous carbon fibers on bending.
(Contents of experiment)
In this experiment, using the same filament as that used in Experiment 1, a fiber-reinforced resin tubular body having the same size as that of Experiment 1 was produced.
Further, in this experiment, the orientation angle of the continuous reinforcing fibers in all the regions is 20 degrees, and the volume content of the continuous carbon fibers is in each of the regions E1 and E2 other than the planned bending region VE and the planned bending region. In the 50% fiber-reinforced resin tubular body (the second embodiment (1)), the orientation angle of the continuous reinforcing fibers in all the regions is 20 degrees, and the volume content of the continuous carbon fibers is 40 in the bending planned region VE %, And in each of the regions E1 and E2 other than the region to be bent, the fiber reinforced resin tubular body (second embodiment (2)) and the orientation angle of continuous reinforcing fibers in all the regions are 20 degrees. And a fiber-reinforced resin tubular body having a continuous carbon fiber volume content of 30% in the planned bending area VE and 50% in each of the areas E1 and E2 other than the planned bending area (second embodiment (3)) It was used. Also, this experiment was performed in the same experimental apparatus and procedure as in Experiment 1.

(Experimental result)
As described in FIG. 8, each fiber reinforced resin tubular body of the second embodiment (1) and the second embodiment (2) did not bend even when subjected to a prescribed tensile load (determination of bendability) However, the fiber-reinforced resin tubular body of the second embodiment (3) was bent, and the bendability was evaluated as ○.

(Discussion)
The present inventors considered the relationship between the volume fraction of continuous carbon fibers and the bendability based on the above-described experimental results.
When bending the fiber-reinforced resin tubular body 1 of the present embodiment, the planned bending area VE is heated until the planned bending area VE becomes plastically deformable. Specifically, the bending planned area VE is heated until the polyamide resin of the filament wound in the bending planned area VE is in a molten state. For this reason, when the polyamide resin forming the bending expected area VE is in a molten state, the continuous carbon fibers forming the bending expected area VE can move (slip) in the molten polyamide resin. In other words, between the continuous carbon fibers forming the bending intended area VE, relative displacement is possible among the molten polyamide resin. As a result, in the melted polyamide resin, when the volume content of the continuous carbon fiber is smaller, interference occurs when the relative displacement is performed following the bending load at the time of bending (which causes the relative displacement to be disturbed) It was estimated that relative displacement is likely to occur and breakage is difficult because there are few continuous carbon fibers. That is, it was presumed that the smaller the volume content of the continuous carbon fiber, the relative displacement between the continuous carbon fibers would make it difficult to break, and therefore the buckling and the break would not easily occur in the planned bending region.

(Conclusion)
The inventors of the present application have found from the above experimental results and discussion that a fiber-reinforced resin tube having a continuous carbon fiber arrangement structure in which the volume fraction of continuous carbon fibers is smaller in the area to be bent than in the area other than the area to be bent. It was concluded that if a body is made, it is possible to provide a fiber-reinforced resin tubular body in which buckling or breakage is unlikely to occur in a region to be bent.

Third Embodiment
A fiber-reinforced resin tubular body according to a third embodiment of the present invention will be described with reference to the drawings.
The fiber-reinforced resin tubular body of the present embodiment is characterized in that the CFRTP tape has an arrangement structure of carbon fibers spirally wound so that a part of the tape overlaps.

As shown in FIG. 5A, the fiber-reinforced resin tubular body 1 of the present embodiment is formed by spirally winding a tape T made of CFRTP so that a part thereof is overlapped. The fiber-reinforced resin tubular body 1 is formed by winding and winding a thermoplastic resin on a mandrel by hoop-wrapping a tape T, and cooling and solidifying the thermoplastic resin. As shown in FIG. 5B, the tape T is formed by so-called plain weave in which wefts we and warps wa are alternately ups and downs and woven. The weft yarn we and the warp yarn wa are PAN-based carbon fiber filaments using a thermoplastic epoxy resin as a matrix resin. As shown in FIG. 5 (c), the weft we has a length corresponding to the width of the tape T, while the warp wa has a length corresponding to the length of the tape T, and It is continuous until the end of the session. That is, the carbon fibers forming the warp yarn wa are continuous carbon fibers, and the carbon fibers forming the weft yarn we are short fibers.
As shown in FIG. 5D, assuming that the width of the tape T is d, the tapes T overlap at the width d1 and deviate at the width Δd. That is, the tape T is wound while being shifted by the width Δd in one turn (one rotation of the mandrel).

[Experiment 3]
The inventors of the present invention conducted experiments to investigate the influence of the width of the tape forming the fiber-reinforced resin tubular body and the overlapping width on bending.
(Contents of experiment)
In this experiment, a fiber-reinforced resin tubular body having the same size as that of Experiment 1 was produced using the tape T described above.
Further, in this experiment, the tape T was wound such that the winding angle with respect to the axis G (axis of the mandrel) of the fiber-reinforced resin tubular body to be completed was about 80 degrees. Then, a fiber-reinforced resin tubular body (third embodiment (1)) prepared by overlapping a tape T having a tape width d of 10 mm and winding it at an overlapping width d1 of 5 mm (a shift width Δd of 5 mm) A fiber-reinforced resin tubular body (third embodiment (2)) prepared by winding a 15 mm tape T at an overlapping width d1 of 10 mm (shift width Δd 5 mm) and a tape T having a tape width d of 15 mm are overlapped A fiber-reinforced resin tubular body (third embodiment (3)) prepared by winding with a width d1 of 5 mm (a displacement width Δd of 10 mm) and a tape T having a tape width d of 20 mm overlap a width d1 of 15 mm (a displacement) The fiber-reinforced resin tubular body (third embodiment (4)) wound with a width Δd of 5 mm and a tape T having a tape width d of 20 mm are overlapped so that the width d1 is 10 mm (displacement width Δd is 10 mm) Create it The fiber-reinforced resin tubular body (third embodiment (5)) was used. Also, this experiment was performed in the same experimental apparatus and procedure as in Experiment 1.

(Experimental result)
As shown in the experimental results of FIG. 8, in the fiber-reinforced resin tubular body of the third embodiment (1), although the bending planned region is broken (the bendability determination is x), the third embodiments (2) to (5) Each of the fiber-reinforced resin tubular bodies of the above was bent (judgement of bendability is ○).

(Discussion)
The present inventors considered the relationship between the width and overlap width of the tape and the bendability based on the above-described experimental results.
When the tape T forming the fiber-reinforced resin tubular body of the third embodiment (2) to (5) which succeeded in bending in this experiment was observed, relative displacement between the tapes T was caused by bending. I understood. FIG. 6 is an explanatory view for explaining the displacement of the tape forming the fiber reinforced resin tubular body shown in FIG. 5 (a), where (a) is an explanatory view of the tape before displacement, and (b) is after displacement It is explanatory drawing of the tape. In FIG. 6, reference symbols T1 to T3 indicate one winding of the wound tape T. Moreover, in order to make the displacement state of tape T intelligible, FIG. 6 is described by the displacement amount larger than the actual displacement amount. As shown in FIG. 6 (a), assuming that the overlapping width of the tape T (T2, T3) before bending is d1, as shown in FIG. 6 (b), bending is performed after bending. The overlapping width d2 of the tape T (T2, T3) outside the bending direction of the area is smaller than the overlapping width d1 before bending (d2 <d1). Further, the overlapping width d3 of the tape T on the inner side in the bending direction of the bent region was larger than the overlapping width d1 before bending (d3> d1).
From the above observation results, the inventors of the present invention absorb the bending load by relative displacement between the tapes T when the fiber reinforced resin tubular body 1 is subjected to a tensile load in the direction indicated by the arrow F2. Since the carbon fiber forming the planned area VE did not break, it was estimated that no buckling or breakage occurred in the planned bending area VE.

  Also, when the thermoplastic epoxy resin forming the bending expected area VE is in a molten state, the weft yarn we and the warp yarn wa forming the bending expected area VE can move (slip) in the molten thermoplastic epoxy resin It will be In other words, relative displacement is possible among the molten thermoplastic epoxy resin between the weft yarns we and the warp yarns wa which form the planned bending region VE. As described above, since the winding angle of the tape T is 45 degrees or more with respect to the axis G of the fiber-reinforced resin tubular body to be completed, it can be inferred that the orientation angle of the warp yarn wa is 45 degrees or more . For this reason, as described in the discussion of Experiment 1, it was presumed that as the orientation angle is larger, warps wa which are continuous carbon fibers are more likely to break because they tend to move following the bending load at the time of bending. On the other hand, weft we had only the length of the tape width, was discontinuous, and there was almost no connection between wefts we, so it was presumed that it was not broken by the bending load.

(Conclusion)
From the experimental results and discussion described above, the inventors of the present invention have found that the tape formed by weaving the carbon fiber with the thermoplastic resin has a configuration structure in which the tape is spirally wound so as to partially overlap. It was concluded that if a reinforced resin tubular body is produced, it is possible to provide a fiber reinforced resin tubular body in which buckling or breakage is unlikely to occur in a region to be bent.

Fourth Embodiment
A fiber-reinforced resin tubular body according to a fourth embodiment of the present invention will be described with reference to the drawings.
In the fiber-reinforced resin tubular body of this embodiment, a tape formed by weaving reinforcing fibers with a thermoplastic resin is partially overlapped with the fiber-reinforced resin tubular body of the first embodiment described above. It is characterized in that it is spirally wound.

[Experiment 4]
The inventors of the present invention conducted an experiment to investigate the bendability of the fiber-reinforced resin tubular body of the present embodiment.
(Contents of experiment)
In this experiment, a fiber reinforced resin in which the orientation angles of the continuous carbon fibers forming the areas E1 and E2 other than the bending planned area VE and the bending planned area VE are set to 45 degrees by the same method as the first embodiment described above. A tubular body was created. Furthermore, the tape T used in the third embodiment described above is wound such that the winding angle with respect to the axis G (axis of the mandrel) of the fiber-reinforced resin tubular body to be completed is about 80 degrees (fourth Embodiment (1)). The tape width d of the tape T used is 20 mm, and the overlapping width d1 is 10 mm (displacement width Δd is 10 mm). And bending was performed by the same apparatus and method as Experiment 1 mentioned above.

(Experimental result)
As shown in the experimental result of FIG. 8, the fiber-reinforced resin tubular body of the fourth embodiment (1) was bent (the determination of bendability is ○).

(Discussion)
The present inventors considered the relationship between the structure and bendability of the fiber-reinforced resin tubular body of the present embodiment based on the above-described experimental results.
In the fiber-reinforced resin tubular body of the fourth embodiment (1), in addition to the fact that the orientation angle of the continuous carbon fiber forming the bending expected area VE is 45 degrees, the tape T wound further in the bending expected area VE Since the winding angle is about 80 degrees, that is, the orientation angle of the continuous carbon fibers forming the tape T is about 80 degrees, all continuous reinforcing fibers forming the scheduled bending area VE are 45 degrees or more. For this reason, continuous carbon fibers forming the bending planned area VE are difficult to be broken because they are relatively displaced following the bending load in the melted thermoplastic resin, and hence it is difficult to break or bend in the bending planned area VE Guessed that would not occur. Furthermore, since wefts we (FIG. 5C) are arranged in the direction of the axis G by the wound tape T in the planned bending area VE, bending strength (rigidity) in the planned bending area VE I guess I was able to boost. Furthermore, the orientation angle of the continuous carbon fibers forming the regions E1 and E2 other than the planned bending region VE is also 45 degrees, and the bending strength is compared with the case where the orientation angle is smaller than 45 degrees, for example 20 degrees. Although it is inferior in (rigidity), since the tape T is wound in the areas E1 and E2 other than the planned bending area VE, it was presumed that the reduction in bending strength could be suppressed.

(Conclusion)
From the above experimental results and discussion, the inventors of the present invention wound continuous carbon fibers at an orientation angle at which relative reinforcing fibers are easily displaced relative to bending to form a matrix of a fiber reinforced resin tubular body, Furthermore, if a fiber-reinforced resin tubular body is produced by winding a plain-woven tape of a filament on a matrix, buckling or breakage is unlikely to occur in a region to be bent, and the bending strength (rigidity) is high. It was concluded that fiber reinforced resin tubular body can be provided.

Other Embodiments
(1) A fiber-reinforced resin tubular body can also be produced by using the fiber-reinforced resin tubular body prepared in the first embodiment as a matrix and winding the tape T on the matrix. If this fiber-reinforced resin tubular body is implemented, it is possible to provide a fiber-reinforced resin tubular body which is unlikely to cause buckling or breakage in the planned bending region VE and which has high compressive strength. In addition, the tape T may be wound only in the planned bending region VE.
(2) A fiber-reinforced resin tubular body can also be produced by using the fiber-reinforced resin tubular body prepared in the second embodiment as a matrix and winding the tape T on the matrix. If this fiber-reinforced resin tubular body is implemented, it is possible to provide a fiber-reinforced resin tubular body which is unlikely to cause buckling or breakage in the planned bending region VE and which has high compressive strength. In addition, the tape T may be wound only in the planned bending region VE.

(3) It is also possible to use pitch-based carbon fiber instead of PAN-based carbon fiber.
(4) As the thermoplastic resin, polypropylene, polyethylene, polyester, polyamide, polycarbonate, polyoxymethylene, ABS, PES, PEEK, polyimide, PMMA or the like can also be used.
(5) Instead of carbon fiber, glass fiber, PBO (polyparaphenylene benzoxazole) fiber, polyarylate fiber, aramid fiber, polyimide fiber, polyphenylene sulfide (PPS) fiber, fluorine fiber, mineral fiber or the like can be used.
(6) As a bending method of the fiber-reinforced resin tubular body, it is possible to use a so-called slide bending method in which a die is pressed against a bending object and bent instead of the stretch bending method.
(7) A method may be used in which a tensile load is applied to both ends of the fiber-reinforced resin tubular body for bending.

[Correspondence between claim and embodiment]
The CFRTP corresponds to the fiber reinforced thermoplastic resin according to claim 1, the polyamide resin or the thermoplastic epoxy resin corresponds to the thermoplastic resin, and the carbon fiber corresponds to the reinforcing fiber.

Reference Signs List 1 fiber reinforced resin tubular body 2 bending apparatus 3 mold 3a R part 4 fixed clamp 5 moving clamp E1, E2 area other than planned bending area S continuous carbon fiber T tape VE planned bending area wa warp we weft θ1, θ2 orientation angle θ3 bending angle

Claims (6)

A fiber-reinforced resin tubular body, which is formed of a fiber-reinforced thermoplastic resin, and in which the thermoplastic resin in the region to be bent can be plastically deformed by heating so that the bending region can be bent.
The arrangement structure of reinforcing fibers in the planned bending area is a configuration structure in which the reinforcing fibers are more easily displaced relative to bending than the area other than the planned bending area. body. The fiber reinforced thermoplastic resin is
At least formed of continuous reinforcing fiber and thermoplastic resin,
The arrangement structure is
The orientation structure of the continuous reinforcing fiber with respect to the axis of the fiber reinforced resin tubular body is an arrangement structure in which the bending expected area is larger than the area other than the bending expected area. Fiber reinforced resin tubular body. The fiber reinforced thermoplastic resin is
At least formed of continuous reinforcing fiber and thermoplastic resin,
The arrangement structure is
The fiber reinforced resin tubular body according to claim 1 or 2, wherein the volume reinforcing ratio of the continuous reinforcing fibers is smaller in the bending expected area than in the area other than the bending expected area. body. The arrangement structure is
The tape according to any one of claims 1 to 3, characterized in that the tape formed by weaving the reinforcing fiber with the thermoplastic resin has an arrangement structure in which the tape is spirally wound so that a part thereof overlaps. The fiber reinforced resin tubular body according to claim 1.   A tape formed by weaving reinforcing fibers with the thermoplastic resin is spirally wound on a portion of the fiber-reinforced resin tubular body according to claim 2 so that a part thereof is overlapped. Fiber reinforced resin tubular body.   A tape formed by weaving reinforcing fibers with the thermoplastic resin is spirally wound on a portion of the fiber-reinforced resin tubular body according to claim 3 so that the tape partially overlaps. Fiber reinforced resin tubular body.

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