U.S. patent application number 14/646947 was filed with the patent office on 2015-10-22 for tubular fiber structure and fiber reinforced composite material.
This patent application is currently assigned to KABUSHIKI KAISHA TOYOTA JIDOSHOKKI. The applicant listed for this patent is KABUSHIKI KAISHA TOYOTA JIDOSHOKKI. Invention is credited to Fujio HORI, Ryuta KAMIYA.
Application Number | 20150299913 14/646947 |
Document ID | / |
Family ID | 50827621 |
Filed Date | 2015-10-22 |
United States Patent
Application |
20150299913 |
Kind Code |
A1 |
HORI; Fujio ; et
al. |
October 22, 2015 |
TUBULAR FIBER STRUCTURE AND FIBER REINFORCED COMPOSITE MATERIAL
Abstract
A tubular fiber structure, which includes a tubular section and
a flange section that is on at least one end of the tubular section
and which is formed by shaping a wound fabric base material.
Inventors: |
HORI; Fujio; (Kariya-shi,
JP) ; KAMIYA; Ryuta; (Kariya-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KABUSHIKI KAISHA TOYOTA JIDOSHOKKI |
Kariya-shi, Aichi |
|
JP |
|
|
Assignee: |
KABUSHIKI KAISHA TOYOTA
JIDOSHOKKI
Kariya-shi, Aichi-ken
JP
|
Family ID: |
50827621 |
Appl. No.: |
14/646947 |
Filed: |
October 24, 2013 |
PCT Filed: |
October 24, 2013 |
PCT NO: |
PCT/JP2013/078764 |
371 Date: |
May 22, 2015 |
Current U.S.
Class: |
428/34.1 |
Current CPC
Class: |
D03D 3/02 20130101; B32B
2605/00 20130101; B32B 5/024 20130101; B32B 2262/105 20130101; B60R
19/03 20130101; B32B 2262/10 20130101; B32B 1/08 20130101; B32B
2262/101 20130101; B32B 2307/56 20130101; D03D 1/00 20130101; B32B
2262/103 20130101; B32B 5/26 20130101; D10B 2505/02 20130101; D03D
13/004 20130101; B32B 5/06 20130101; B32B 2262/106 20130101; B32B
2307/50 20130101; B32B 2262/02 20130101; B32B 5/22 20130101; B32B
2250/20 20130101; B32B 2260/046 20130101; B32B 2262/0269 20130101;
B32B 2260/021 20130101; B32B 2597/00 20130101; B32B 5/022
20130101 |
International
Class: |
D03D 3/02 20060101
D03D003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 29, 2012 |
JP |
2012-261056 |
Claims
1. A tubular fiber structure comprising: a tube; and a flange
located on at least one side of the tube; wherein the tubular fiber
structure is formed by shaping a fabric base material that is
rolled.
2. The tubular fiber structure according to claim 1, wherein the
flange is formed by a woven texture, and the tube is formed by a
non-woven texture.
3. The tubular fiber structure according to claim 1, further
comprising a reinforcement portion arranged at an inner side of the
tube and formed by a fabric base material.
4. The tubular fiber structure according to claim 3, wherein the
fabric base material forming the tube and the flange includes a
tube-corresponding portion corresponding to the tube, the
tube-corresponding portion includes a rolled inner end located at a
radially inner side when the tube-corresponding portion is rolled
to form the tube, and the fabric base material of the reinforcement
portion is continuous with the rolled inner end.
5. The tubular fiber structure according to claim 1, wherein the
tube is formed to be three-dimensional by sewing together
overlapping layers of the fabric base material with a stitching
thread.
6. The tubular fiber structure according to claim 1, wherein a
fabric base material forming the tube includes a first fabric base
material, in which threads serving as reinforcement fibers are laid
out at angles of 0 degrees and 90 degrees, and a second fabric base
material, in which threads serving as reinforcement fibers are laid
out angles of +45 degrees and -45 degrees.
7. The tubular fiber structure according to claim 1, wherein a
portion of the fabric base material forming the flange includes
threads extending continuously over the entire circumference in a
circumferential direction and laid out in a radial direction.
8. The tubular fiber structure according to claim 1, wherein a
portion of a fabric base material forming the flange includes
threads extending in a circumferential direction and laid out in a
radial direction, and the threads located at outer positions in the
radial direction of the flange are thicker.
9. The tubular fiber structure according to claim 1, wherein a
portion of a fabric base material forming the flange includes
threads extending in a circumferential direction and laid out in a
radial direction, and the threads are laid out in intervals that
become smaller at outer positions in the radial direction.
10. The tubular fiber structure according to claim 1, wherein the
tube is tapered.
11. The tubular fiber structure according to claim 10, wherein the
tube has a thickness that changes in a stepped manner from one end
to another end of the tube.
12. The tubular fiber structure according to claim 1, further
comprising a positioning tube that projects from the flange.
13. A fiber reinforced composite material comprising the tubular
fiber structure according to claim 1 as a reinforcement.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a National Stage of International
Application No. PCT/JP2013/078764, filed Oct. 24, 2013, claiming
priority based on Japanese Patent Application No. 2012-261056,
filed Nov. 29, 2012, the contents of all of which are incorporated
herein by reference in their entirety.
FIELD OF THE INVENTION
[0002] The technology of the present disclosure relates to a
tubular fiber structure and a fiber reinforced composite material
that uses the tubular fiber structure as a reinforcement.
BACKGROUND OF THE INVENTION
[0003] A typical automobile includes bumpers secured to the front
and rear of the vehicle body to absorb impact energy of a collision
and protect the vehicle body and the vehicle occupants during a
collision. A bumper needs to absorb, in an irreversible manner, the
energy of the load that is produced when the automobile collides
with an obstacle. There are structures that support the bumper with
a substantially tubular energy absorption member formed from
fiber-reinforced plastic to increase energy absorption.
[0004] In such a case, as shown in FIG. 26, a bumper beam 81 needs
to be supported through a tubular energy absorption member 82 by a
frame body 83. Since the energy absorption member 82 does not have
a flange, the two ends of the energy absorption member 82 are
coupled to the bumper beam 81 and the frame body 83 with a
complicated structure.
[0005] Patent document 1 discloses an example of a ceramic group
composite member that includes flanges on two ends of a tube. The
ceramic group composite member is formed from ceramic fibers and
serves as a ceramic group composite member applied to a turbine
vane. As shown in FIG. 27, the ceramic fiber reinforcement member
used as the ceramic group composite member includes spread portions
92 and plain weave plates 93. The spread portions 92 are formed by
cutting slits in the two ends of a tubular vane 91, which is formed
by a three-axis braid texture, and bending the cut ends. The plain
weave plates 93 of ceramic fibers hold the spread portions 92. In
this manner, the ceramic group composite member includes flanges at
the two ends of a tube.
[0006] Patent document 2 discloses a rotor, which is formed from a
composite material and includes a cylindrical tube projecting from
an inner circumference of a toroidal disk-shaped main body, and a
disk-shaped fabric used as a reinforcement for the rotor. As shown
in FIG. 28, a disk-shaped fabric 95 includes radial threads 96,
which extend radially from the center of the disk-shaped fabric 95,
and circumferential threads 97, which extend spirally (helically)
around the center. The radial threads 96 and the circumferential
threads 97 form a disk-shaped main body 98. The circumferential
threads 97 are not woven at the central portion of the disk-shaped
fabric 95 so that an opening is formed at the central portion. The
radial threads 96 form a long extension 99 that projects from the
circumference of the opening. A plurality of the disk-shaped
fabrics 95 are stacked and impregnated with a resin to form the
composite material rotor.
PRIOR ART DOCUMENT
Patent Documents
[0007] Patent Document 1: Japanese Laid-Open Patent Publication No.
2003-148105
[0008] Patent Document 2: Japanese Laid-Open Patent Publication No.
2-234944
SUMMARY OF THE INVENTION
[0009] When applying the structure of patent document 1 to an
energy absorption member, the coupling of the energy absorption
member to the bumper beam 81 and the frame body 83 at the flanges
simplifies the coupling structure. However, in the structure of
patent document 1, the slits are cut into the two ends of the tube,
which is formed by a three-axis braid texture, and the cut ends are
bent to form the flanges. Thus, when using the structure of patent
document 1 as a reinforcement for fiber-reinforced plastic to form
the energy absorption member, cracks may form from the slits and
lower the energy absorption efficiency. Further, when increasing
the amount of the axial threads to counter compression in the
three-axis braid texture, undulations (crimps) increase in the
radial threads. This lowers the strength.
[0010] When using the disk-shaped fabric 95 of patent document 2 to
form an energy absorption member having a flange at one side,
disk-shaped fabrics 95 having central openings with different
diameters are stacked in layers to form the tube. This results in a
complicated manufacturing process. Further, the threads serving as
the reinforcement fibers of the tube are in a free state. Thus,
when manufacturing a composite material, it is difficult to lay out
the threads, and it is difficult to increase the strength.
[0011] It is an object of the present disclosure to provide a
tubular fiber structure that includes a flange and obtains the
necessary strength when used as reinforcement for tubular
fiber-reinforced composite material to facilitate coupling to
another member. It is also on object of the present disclosure to
provide a fiber reinforced composite material that uses the tubular
fiber structure as the reinforcement.
[0012] One aspect of the present disclosure is a tubular fiber
structure including a tube and a flange located on at least one
side of the tube. The tubular fiber structure is formed by shaping
a fabric base material that is rolled. Here, the "fabric base
material" is formed by threads laid out to extend in at least two
directions and includes at least a portion that is woven from
threads (interweaved portion). In the present description,
"threads" are not limited to twisted fiber bundles and include
non-twisted fiber bundles.
[0013] In this structure, the tubular fiber structure includes the
flange that is shaped at the region of the end of the rolled fabric
base material. Thus, the formation of cracks from the boundary of
the flange and the tube is limited when forming a composite
material. This differs from when cutting slits into the region at
the end of a tubular braid texture. Further, the tubular fiber
structure is entirely formed by a fabric base material. Thus,
compared to when threads serving as reinforcement fibers of a tube
are free, the threads may be laid out in an orderly manner when
manufacturing a composite material. Accordingly, when the tubular
fiber structure, which includes the flange, is used as a
reinforcement for a tubular fiber reinforced composite material
that can easily be coupled to another member, the necessary
strength may be ensured.
[0014] A fiber reinforced composite material according to one
embodiment of the present disclosure includes the tubular fiber
structure of the present disclosure as a reinforcement.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a schematic perspective view showing a tubular
fiber structure of a first embodiment.
[0016] FIG. 2 is a schematic plan view showing the woven texture of
a fabric base material that forms the tubular fiber structure of
FIG. 1.
[0017] FIG. 3A is a schematic view showing a portion, cut out from
a roll, of the fabric base material that forms the tubular fiber
structure of FIG. 1, FIG. 3B is a schematic diagram of the cut-out
fabric base material, and FIG. 3C is a partially enlarged plan view
of FIG. 3C.
[0018] FIG. 4A is a schematic plan view of a jig used to shape the
fabric base material of FIG. 3, and FIG. 4B is a schematic
perspective view showing the shaping of the flange in the tubular
fiber structure of FIG. 1.
[0019] FIG. 5 is a schematic perspective view showing a tubular
fiber structure of a second embodiment.
[0020] FIG. 6A is a schematic view showing a portion, cut out from
a roll, of a fabric base material forming the tubular fiber
structure of FIG. 5, and FIG. 6B is a schematic view of the cut-out
fabric base material.
[0021] FIG. 7A is a cross-sectional view of a jig used to shape the
fabric base material of FIG. 6, and FIG. 7B is a schematic
cross-sectional view showing the relationship of the jig and the
fabric base material when forming the tubular fiber structure of
FIG. 5.
[0022] FIG. 8 is a schematic perspective view showing a tubular
fiber structure of a third embodiment.
[0023] FIG. 9 is a schematic view showing the relationship of
stitching threads and fiber bundles, which are overlapped in a
thicknesswise direction of the tube in the tubular fiber structure
of FIG. 8.
[0024] FIG. 10 is a schematic perspective view showing the tube of
the tubular fiber structure of FIG. 8 when stitched with stitching
wires.
[0025] FIG. 11A is a schematic view showing a fabric base material
in a fourth embodiment when a portion cut out from a roll is a
second fabric base material in which the reinforcement fibers are
laid out at an angle of .+-.45 degrees, and FIG. 11B is a schematic
view of the cut-out fabric base material.
[0026] FIG. 12A is a schematic view showing a fabric base material
in the fourth embodiment when a portion cut out from a roll is a
first fabric base material in which the reinforcement fibers are
laid out at an angle of 0 degrees and 90 degrees, and FIG. 12B is a
schematic view of the cut-out fabric base material.
[0027] FIG. 13 is a schematic perspective view showing a tubular
fiber structure of a fifth embodiment.
[0028] FIG. 14A is a schematic view showing the tubular fiber
structure of FIG. 13 when a portion cut out from a roll is a first
fabric base material in which the reinforcement fibers are laid out
at an angle of 0 degrees and 90 degrees, and FIG. 14B is a
schematic view of the cut-out fabric base material.
[0029] FIG. 15A is a schematic view showing the tubular fiber
structure of FIG. 13 when a portion cut out from a roll is a second
fabric base material in which the reinforcement fibers are laid out
at an angle of .+-.45 degrees, and FIG. 15B is a schematic view of
the cut-out fabric base material.
[0030] FIG. 16 is a graph showing the relationship of load and
displacement when the tubular fiber structure of FIG. 13 is applied
to an energy absorption member.
[0031] FIG. 17 is a schematic view showing a flange-corresponding
portion in a fabric base material of a further embodiment.
[0032] FIG. 18 is a schematic perspective view showing a tubular
fiber structure of a further embodiment.
[0033] FIG. 19 is a schematic perspective view showing a tubular
fiber structure of a further embodiment.
[0034] FIG. 20 is a schematic perspective view showing a tubular
fiber structure of a further embodiment.
[0035] FIG. 21A is a schematic perspective view showing a tubular
fiber structure of a further embodiment, and FIG. 21B is a
schematic perspective view showing the fabric base material of FIG.
21A.
[0036] FIG. 22 is a schematic view showing a fabric base material
of a further embodiment.
[0037] FIGS. 23A and 23B are schematic views showing a tubular
fiber structure of a further embodiment.
[0038] FIGS. 24A and 24B are schematic views showing a tubular
fiber structure of a further embodiment.
[0039] FIG. 25 is a schematic view showing a lock stitch in a
further embodiment.
[0040] FIG. 26 is a schematic perspective view showing a coupled
energy absorption member.
[0041] FIG. 27 is a schematic perspective view of the prior
art.
[0042] FIG. 28 is a schematic perspective view showing further
prior art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
[0043] A first embodiment of a tubular fiber structure will now be
described with reference to FIGS. 1 to 4.
[0044] Referring to FIG. 1, a tubular fiber structure 10 is formed
by rolling a sheet of a fabric base material 11 and shaping the
rolled fabric base material 11. The tubular fiber structure 10
includes a tube 12 and a flange 13, which is located on at least
one side (i.e., one axial end) of the tube 12. In this embodiment,
the tube 12, which is tubular and has a circular cross-section,
includes the flange 13 at two sides (two axial ends). The "fabric
base material" is formed by threads laid out to extend in at least
two directions and includes at least a portion that is woven from
threads (interweaved portion).
[0045] Referring to FIG. 2, the fabric base material 11 includes a
woven texture 14 and a non-woven texture 15. As shown in FIG. 3A,
the fabric base material 11 of this embodiment includes the woven
texture 14 at the two widthwise sides of the fabric base material
11 and the non-woven texture 15 at the middle region in the
widthwise direction between the two woven textures 14. The woven
textures 14 each have a predetermined width corresponding to the
width of the flanges 13 in the radial direction. The non-woven
texture 15 has a predetermined width corresponding to the axial
length of the tube 12. That is, the tube 12 of the tubular fiber
structure 10 is formed by the non-woven texture 15, and the flanges
13 of the tubular fiber structure 10 are formed by the woven
textures 14. The woven textures 14 are formed by laying out threads
(fiber bundles), which function as reinforcement fibers of a
composite material, to extend in at least two directions, with
intersections of threads extending in different directions defining
woven portions (interweaved portion).
[0046] In detail, as shown in FIG. 2, the fabric base material 11
includes reinforcement threads 16, which are laid out at an angle
of 0 degrees, reinforcement threads 17, which are laid out at an
angle of 90 degrees, auxiliary threads 16a, which are laid out at
an angle of 0 degrees, and auxiliary threads 17a, which are laid
out at an angle of 90 degrees. The layout angle of a thread is the
angle of the direction the thread extends relative to the
longitudinal direction of the fabric base material 11. The layout
angle of 0 degrees indicates that the thread extends in a direction
parallel to the longitudinal direction of the fabric base material
11. The layout angle of 90 degrees indicates that the thread
extends in a direction perpendicular to the longitudinal direction
of the fabric base material 11. That is, the warps of the fabric
are the threads laid out at 0 degrees, and the wefts are the
threads laid out at 90 degrees.
[0047] The portions of the reinforcement threads 16 and the
reinforcement threads 17 corresponding to the flanges 13 form the
woven textures 14. The portions of the reinforcement threads 16 and
the reinforcement threads 17 corresponding to the tube 12 form the
non-woven texture 15. The woven texture 14 forms a plain weave. In
the portions of the reinforcement threads 16 and the reinforcement
threads 17 corresponding to the tube 12, the reinforcement threads
16 are all laid out along the same plane at the same side of the
reinforcement threads 17, and the reinforcement threads 17 are all
laid out along the same plane at the same side of the reinforcement
threads 16. In FIG. 2, the reinforcement threads 16 are laid out at
the upper side of the reinforcement threads 17.
[0048] The auxiliary threads 16a are laid out adjacent to the
reinforcement threads 16 in a portion corresponding to the tube 12.
The auxiliary threads 17a are laid out adjacent to the
reinforcement threads 17 in a portion corresponding to the tube 12
and also extend to portions corresponding to the flanges 13. The
auxiliary threads 16a are laid out to alternately form woven
portions (interweaved portions) with the reinforcement threads 17
and the auxiliary threads 17a. The auxiliary threads 17a are laid
out to form woven portions (interweaved portions) with the
reinforcement threads 16 in portions corresponding to the flanges
13 and alternately form woven portions (interweaved portions) with
the reinforcement threads 16 and the auxiliary threads 16a in
portions corresponding to the tube 12. Thus, although the
reinforcement threads 16 and the reinforcement threads 17 that form
the tube 12 do not form woven portions (interweaved portions) with
each other in the tube 12, the auxiliary threads 16a alternately
form woven portions (interweaved portions) with the reinforcement
threads 17 and the auxiliary threads 17a, and the auxiliary threads
17a alternately form woven portions (interweaved portions) with the
reinforcement threads 16 and the auxiliary threads 16a. Thus, the
reinforcement threads 16 and the reinforcement threads 17 are held
at predetermined positions.
[0049] The threads (fiber bundles) forming the fabric base material
11 are selected in accordance with the required performance and may
be, for example, inorganic fibers such as carbon fibers, glass
fibers, ceramic fibers, or metal fibers, or may be organic fibers
having high strength. Organic fibers including high strength may be
aramid fibers, poly-p-phenylene benzo bis-oxazole fibers,
polyallylate fibers, ultra-high molecular weight polyethylene
fibers, or the like. Carbon fibers are preferred when the fiber
reinforced composite material requires, for example, high rigidity
and high strength. The use of glass fibers in the fiber bundles
lowers costs.
[0050] A method for manufacturing the tubular fiber structure 10
will now be described.
[0051] First, referring to FIG. 3A, the fabric base material 11 is
cut out from a roll 50 including the woven textures 14 at the two
widthwise sides. As shown in FIG. 3B, the fabric base material 11
includes a tetragonal tube-corresponding portion 11a and
trapezoidal flange-corresponding portions 11b, which are formed
continuously with the two widthwise sides of the tube-corresponding
portion 11a. Triangular portions are located at the two ends of
each flange-corresponding portion 11b. As shown in FIG. 3C, wefts
are eliminated from the triangular portions leaving only the warps.
The wefts of the flange-corresponding portions 11b refer to the
reinforcement threads 17 and the auxiliary threads 17a laid out at
an angle of 90 degrees, and the warps of the flange-corresponding
portions 11b refer to the reinforcement threads 16 laid out at an
angle of 0 degrees.
[0052] FIG. 4A shows a shaping jig 51 (shaping mold) used to roll
the fabric base material 11 and shape the flanges 13. The jig 51
(shaping mold) includes a tube-shaped outer jig 51a, which is
separable into two pieces, and a bar-shaped inner jig 51b, which is
able to hold the fabric base material 11 in cooperation with the
outer jig 51a. The outer jig 51a has an inner diameter
corresponding to the outer diameter of the tubular fiber structure
10. The inner jig 51b has an outer diameter corresponding to the
inner diameter of the tubular fiber structure 10.
[0053] The jig 51 is used to roll the fabric base material 11 into
a tubular form and shape the flanges 13.
[0054] The tube-corresponding portion 11a of the fabric base
material 11 is first rolled around the outer side of the inner jig
51b. Here, the flange-corresponding portions 11b project from the
two ends of the inner jig 51b. Then, the outer jig 51a is fitted
onto the outer side of the tube-corresponding portion 11a of the
fabric base material 11, which is rolled around the inner jig 51b.
When the tube-corresponding portions 11a are held between the inner
jig 51b and the outer jig 51a, the jig 51 is held by a support
device (not shown). The support device supports the inner jig 51b
at a recess (not shown) formed in an end surface of the inner jig
51b and supports the outer jig 51a from an outer side.
[0055] As shown in FIG. 4B, the flange-corresponding portions 11b
of the fabric base material 11 held by the jig 51 undergo shaping.
The shaping of the flange-corresponding portion 11b is first
performed by, for example, using a manipulator to bend the
flange-corresponding portion 11b projecting from one end of the jig
51 while widening the intervals of the reinforcement threads 17 and
the auxiliary threads 17a that form the flange-corresponding
portion 11b toward outer sides in the radial direction. The
overlapping sections of the flange-corresponding portion 11b
(overlapping sections of the fabric base material 11) that has
undergone shaping are fixed by an adhesive agent or by stitches.
Then, the flange-corresponding portion 11b projecting from the
other end of the jig 51 is also shaped in the same manner, and the
overlapping sections of the flange-corresponding portion 11b that
has undergone shaping are fixed by an adhesive agent or by
stitches. This completes the manufacturing of the tubular fiber
structure 10.
[0056] The tubular fiber structure 10, which is formed as described
above, is used as a reinforcement for a fiber reinforced composite
material. The tubular fiber structure 10 is, for example,
impregnated with a matrix resin and hardened in an RTM process to
form a fiber reinforced composite material. More specifically, the
tubular fiber structure 10, removed from the outer jig 51a and the
inner jig 51b, is accommodated in a cavity of a mold. Then, the
cavity is closed, and the cavity is depressurized. After the cavity
becomes almost vacuum, the cavity is filled with uncured
thermosetting resin. Then, the resin is heated and cured to
manufacture the fiber reinforced composite material. The
thermosetting resin may be unsaturated polyester resin, epoxy
resin, phenol resin, or the like.
[0057] This embodiment has the advantages described below.
[0058] (1) The tubular fiber structure 10 is formed by rolling a
sheet of the fabric base material 11 and shaping the rolled fabric
base material 11 so that at least one side of the tube 12 includes
the flange 13. This differs from when forming a flange by cutting
slits into a tubular braid texture in that cracks do not form from
the boundary of the flange 13 and the tube 12 when forming a
composite material. Further, the tubular fiber structure 10 is
entirely formed by the fabric base material 11. Thus, compared to
when the threads forming a tube of a fiber reinforced composite
material are free, the threads may be laid out in an orderly manner
when manufacturing a composite material. Accordingly, when the
tubular fiber structure 10, which includes flanges, is used as a
reinforcement for a fiber reinforced composite material that can
easily be coupled to another member, the necessary strength may be
ensured.
[0059] (2) The flanges 13 are formed by the woven texture 14, and
the tube 12 is formed by the non-woven texture 15. Thus, the
reinforcement fibers (reinforcement threads 16 and 17) forming the
tube 12 do not include crimps. Accordingly, when the tubular fiber
structure 10 is used to form a composite material, the composite
material has higher strength and rigidity than when the flanges 13
and the tube 12 are both formed by the woven texture 14.
[0060] (3) The tubular fiber structure 10 includes the flanges 13
at opposite sides of the tube 12. The tube 12 is formed by the
reinforcement threads 16 and 17 of the non-woven texture 15.
Accordingly, when a composite material (fiber reinforced resin)
employing the tubular fiber structure 10 as a reinforcement base
material is used to absorb impacts, for example, when using such a
composite material as an energy absorption member for supporting a
vehicle bumper, coupling is facilitated and impact energy is
efficiently absorbed.
Second Embodiment
[0061] A second embodiment will now be described with reference to
FIGS. 5 to 7. This embodiment differs from the tubular fiber
structure 10 of the first embodiment in that a reinforcement
portion 18 formed by a fabric base material 21 is arranged at the
inner side of the tube 12. Otherwise, the structure is basically
the same as the tubular fiber structure 10 of the first embodiment.
Same reference numerals are given to those components that are the
same as the corresponding components of the first embodiment. Such
components will not be described in detail.
[0062] As shown in FIG. 5, the fabric base material 21 of the
reinforcement portion 18 is continuous with a rolled inner end 11d
of the tube-corresponding portion 11a, which corresponds to the
tube 12, in the fabric base material 11 forming the tube 12 and the
flanges 13. The fabric base material 21 is arranged so as to extend
in the radial direction of the tube 12. The fabric base material 21
includes a fixed portion 21a, which is fixed along the inner
surface of the tube 12 at the opposite side of a position
continuous with the tube-corresponding portion 11a in the tube 12.
The fixed portion 21a is fixed to the inner surface of the tube 12
by an adhesive agent or stitches (not shown).
[0063] A method for manufacturing the tubular fiber structure 10
will now be described.
[0064] As shown in FIGS. 6A and 6B, the fabric base material 11,
which forms the tube 12 and the flanges 13, and the fabric base
material 21, which forms the reinforcement portion 18, are cut out
integrally from the roll 50. The fabric base material 21 is formed
continuously with the tube-corresponding portion 11a and has the
same width as the tube-corresponding portion 11a. The fabric base
material 21 is formed to have a length that is the sum of the inner
diameter of the tube 12 and the length of the fixed portion
21a.
[0065] When manufacturing the tubular fiber structure 10, the inner
jig 51b of the jig 51 has a structure that differs from the inner
jig 51b of the first embodiment. As shown in FIG. 7A, in the jig
51, the outer jig 51a and the inner jig 51b are both formed by two
separate pieces. More specifically, the inner jig 51b includes
semi-cylinders and a recess in each of the two end surfaces.
[0066] Referring to FIG. 7B, when the fabric base material 21 is
held between the two inner jigs 51b so that the fixed portion 21a
of the fabric base material 21 extends along the circumferential
surface of the inner jig 51b, the tube-corresponding portion 11a of
the fabric base material 11 is rolled around the circumferential
surfaces of the two inner jigs 51b. Further, the outer jig 51a is
fitted to the outer side of the tube-corresponding portion 11a of
the fabric base material 11, which is rolled around the inner jigs
51b. When the tube-corresponding portions 11a are held between the
inner jig 51b and the outer jig 51a, the jig 51 is held by a
support device (not shown). Then, in the same manner as the first
embodiment, the flange-corresponding portions 11b of the fabric
base material 11 held by the jig 51 is shaped with, for example, a
manipulator. In FIG. 7B, to ease understanding of the relationship
of the jig 51 with the fabric base material 11 and the fabric base
material 21, a gap is shown between the jig 51 and the fabric base
materials 11 and 21 and between the overlapping portions of the
fabric base material 11.
[0067] In addition to advantages (1) to (3) of the first
embodiment, this embodiment has the advantages described below.
[0068] (4) The tubular fiber structure 10 includes the
reinforcement portion 18, which is formed by the fabric base
material 21, at the inner side of the tube 12. In this structure,
when using the tubular fiber structure 10 as an impact absorption
composite material, the absorption amount of impact energy may be
increased and buckling may be limited as compared with when the
reinforcement portion 18 does not exist. Further, when using the
tubular fiber structure 10 as a composite material that receives a
large aerodynamic force like a turbine blade, deformation caused by
aerodynamic force may be limited.
[0069] (5) The fabric base material 21 of the reinforcement portion
18 is continuous with the rolled inner end 11d of the
tube-corresponding portion 11a of the fabric base material 11,
which forms the tube 12 and the flanges 13. With this structure,
the reinforcement portion 18 may be formed more easily at a
predetermined position than when forming the reinforcement portion
18 with a fabric base material 21 that is separate from the fabric
base material 11 before integration with the tube 12.
Third Embodiment
[0070] A third embodiment will now be described with reference to
FIGS. 8 to 10. This embodiment differs from the first embodiment in
that multiple layers of the fabric base material 11 are stacked and
sewn together with stitching threads 22 so that the tube 12 is
three-dimensional. Same reference numerals are given to those
components that are the same as the corresponding components of the
first embodiment. Such components will not be described in
detail.
[0071] As shown in FIGS. 8 and 9, the overlapping layers of the
fabric base material 11 at the tube 12 are lock-stitched with the
stitching threads 22 so that the tubular fiber structure 10 is
three-dimensional. As shown in FIG. 9, the stitching threads 22
include a piercing thread 22a, which is pierced through and
returned from portions where the fabric base material 11 is
overlapped in layers, and a locking thread 22b, which locks the
piercing thread 22a to the fabric base material 11 at portions of
the fabric base material 11 where the piercing thread 22a is
pierced through and returned. The piercing thread 22a is sewn at
predetermined intervals in the circumferential direction of the
tube 12. The locking thread 22b is laid out at the inner surface
side of the tube 12 parallel to the axial direction of the tube 12.
A lockstitch refers to a stitch that uses two threads, namely, a
first thread (upper thread) and a second thread (lower thread) and
entwines loops of the first thread with the second thread. In this
embodiment, the piercing thread 22a corresponds to the first
thread, and the locking thread 22b corresponds to the second
thread.
[0072] The stitching method will now be described. As shown in FIG.
10, the tubular fiber structure 10, which includes the flanges 13
on the two ends of the tube 12, is stitched when supported by a
support device (not shown) with the tube 12 extending in the
vertical direction.
[0073] An insertion device for the piercing thread 22a includes
piercing thread insertion needles 23, which are laid out along a
single line in the axial direction (vertical direction as viewed in
FIG. 10) of the tube 12. The piercing thread insertion needles 23
are simultaneously reciprocated to simultaneously insert the
piercing threads 22a. The piercing thread insertion needles 23
insert the piercing threads 22a so that the piercing threads 22a
are inserted through the tube 12 from the outer side, looped (not
shown) at the inner side, and then returned.
[0074] An insertion device for the locking thread 22b includes a
single locking thread needle 24. The locking thread needle 24 is
arranged at a standby position above the tube 12 and is
reciprocally movable through the loops of the piercing threads 22a
formed by the piercing thread insertion needs 23 along a single
line at the inner side of the tube 12. When moved forth, the
locking thread needle 24 passes through the loops of the piercing
threads 22a from the standby position. When moved back, the locking
thread needle 24 moves with the locking thread 22b hooked to the
distal end of the locking thread needle 24 and returns through the
loops of the piercing threads 22a with the locking thread 22b. The
locking thread 22b is fed from a locking thread feeding unit 25
located below the tube 12. Then, a tension adjustment unit (not
shown) functions to pull the piercing threads 22a and tighten the
piercing threads 22a, which are inserted into the tube 12 and
locked by the locking thread 22b. This completes a single insertion
cycle of the piercing threads 22a. Whenever a single insertion
cycle of the piercing threads 22a is completed, the tube 12, the
piercing thread insertion needles 23, the locking thread needle 24,
and the locking thread feeding unit 25 are relatively rotated to
sequentially stitch the tube 12 and manufacture the tubular fiber
structure 10 shown in FIG. 8. The distal end of the locking thread
needle 24 includes a latch (not shown) so that the locking thread
needle 24 is not caught in a loop when passing through the loops of
the piercing threads 22a.
[0075] In addition to advantages (1) to (3) of the first
embodiment, this embodiment has the advantages described below.
[0076] (6) The overlapped layers of the fabric base material 11 are
sewn together with the stitching threads 22 so that the tube 12 is
three-dimensional. Thus, in comparison with a structure in which
the overlapping layers of the fabric base material 11 is not sewn
together with the stitching threads 22, the energy absorption
characteristics are improved when using the tubular fiber structure
10 as a composite material for absorbing impacts. Further, when
using the tubular fiber structure 10 as a composite material that
needs to release heat out of the tube 12, the fibers extending in
the thicknesswise direction increase thermal conductivity in the
thicknesswise direction and allows for the release of heat from the
high-temperature side.
[0077] (7) The stitching threads 22, namely, the piercing threads
22a and the locking thread 22b, sew the fabric base material 11 in
a lockstitch with the locking thread 22b entwined with the loops of
the piercing threads 22a. This restricts easy removal of the
stitching threads as compared with a chainstitch that forms
continuous chains with loops formed from a single thread.
Fourth Embodiment
[0078] A fourth embodiment will now be described with reference to
FIGS. 11 and 12. The tubular fiber structure 10 of this embodiment
differs from the first embodiment in that the tube 12 is formed
from two types of fabric base materials, namely, a first fabric
base material 11, in which the threads serving as the reinforcement
fibers are laid out at angles of 0 degrees and 90 degrees, and a
second fabric base material 31, in which the threads serving as the
reinforcement fibers are laid out at angles of +45 degrees and -45
degrees. Same reference numerals are given to those components that
are the same as the corresponding components of the first
embodiment. Such components will not be described in detail. The
"layout angle of a thread" refers to the angle of a direction
corresponding to the circumferential direction when the fabric base
material is rolled relative to the direction the thread
extends.
[0079] Referring to FIGS. 11A and 11B, the second fabric base
material 31, in which the layout angles of the threads serving as
the reinforcement fibers are +45 degrees and -45 degrees, is cut
out from a roll 60 of the non-woven texture 15, in which the layout
angles of the threads serving as the reinforcement fibers are 0
degrees and 90 degrees. The second fabric base material 31 is cut
out so that the angle of the longitudinal direction of the second
fabric base material 31 is 45 degrees relative to the longitudinal
direction of the roll 60. The second fabric base material 31 has
the same width as the tube-corresponding portion 11a of the first
fabric base material 11 shown in FIGS. 12A and 12B, and the second
fabric base material 31 has the same length as the
tube-corresponding portion 11a.
[0080] Referring to FIGS. 12A and 12B, the first fabric base
material 11, in which the layout angles of the threads serving as
the reinforcement fibers are 0 degrees and 90 degrees, is cut out
from the roll 50. The roll 50 includes the woven textures 14 at the
two widthwise sides and the non-woven texture 15 at the middle
region in the widthwise direction between the two woven textures
14. In the same manner as the fabric base material 11 of the first
embodiment, the first fabric base material 11 includes the
tube-corresponding portion 11a and the flange-corresponding portion
11b.
[0081] When manufacturing the tubular fiber structure 10, a jig 51
similar to that of the first embodiment is used. First, the second
fabric base material 31 is stacked on the tube-corresponding
portion 11a of the first fabric base material 11 and rolled around
the inner jig 51b with the second fabric base material 31 located
at the outer side. Then, the outer jig 51a is fitted to the outer
side of the second fabric base material 31, and the first and
second fabric base materials 11 and 31 are held between the outer
jig 51a and the inner jig 51b. Further, in the same manner as the
first embodiment, the flange-corresponding portions 11b projecting
from the two ends of the jig 51 are shaped to form the tubular
fiber structure 10. As a result, in the obtained tubular fiber
structure 10, a layer in which the layout angles of the threads
serving as the reinforcement fibers are 0 degrees and 90 degrees
and a layer in which the layout angles of the threads serving as
the reinforcement fibers are +45 degrees and -45 degrees are
alternately stacked.
[0082] In addition to advantages (1) to (3) of the first
embodiment, this embodiment has the following advantage.
[0083] (8) The tube 12 of the tubular fiber structure 10 includes
the first fabric base material 11, in which the layout angles of
the threads serving as the reinforcement fibers are 0 degrees and
90 degrees, and the second fabric base material 31, in which the
layout angles of the threads serving as the reinforcement fibers
are +45 degrees and -45 degrees. This structure increases the
rigidity in a plane and limits buckling when forming a composite
material in comparison with a structure that forms the tube 12 with
only the fabric base material 11, in which the layout angles of the
threads serving as the reinforcement fibers are 0 degrees and 90
degrees.
Fifth Embodiment
[0084] A fifth embodiment will now be described with reference to
FIGS. 13 to 16. The tubular fiber structure 10 of this embodiment
differs from the fourth embodiment in that the tube 12 is tapered.
Same reference numerals are given to those components that are the
same as the corresponding components of the fourth embodiment. Such
components will not be described in detail.
[0085] Referring to FIG. 13, the tube 12 has an inner diameter that
is fixed and an outer diameter that is changed in a stepped manner.
Thus, the thickness of the tubular fiber structure 10 changes in a
stepped manner from one end to the other end.
[0086] Referring to FIGS. 14A and 14B, the first fabric base
material 11, which is an element forming the tubular fiber
structure 10 and in which the layout angles of the threads serving
as the reinforcement fibers are 0 degrees and 90 degrees, is cut
out from the roll 50. The roll 50 includes the woven textures 14 at
the two widthwise sides and the non-woven texture 15 at the middle
region in the widthwise direction between the two woven textures
14. In the same manner as the first fabric base material 11 of the
fourth embodiment, the first fabric base material 11 includes the
tube-corresponding portion 11a and the flange-corresponding
portions 11b. Further, the first fabric base material 11 includes a
taper-corresponding portion 11c that is continuous with the
tube-corresponding portion 11a, which has a fixed width, and has a
gradually decreasing width.
[0087] Referring to FIGS. 15A and 15B, the second fabric base
material 31, which is an element forming the tubular fiber
structure 10 and in which the layout angles of the threads serving
as the reinforcement fibers are +45 degrees and -45 degrees, is cut
out from the roll 60. The roll 60 includes the non-woven texture
15, in which the layout angles of the threads serving as the
reinforcement fibers are 0 degrees and 90 degrees. The second
fabric base material 31 is cut out so that the angle of the
longitudinal direction of the second fabric base material 31 is 45
degrees relative to the longitudinal direction of the roll 60. The
second fabric base material 31 includes a tube-corresponding
portion 31a and a taper-corresponding portion 31c, which is
continuous with the tube-corresponding portion 31a. The
tube-corresponding portion 31a has the same width and length as the
tube-corresponding portion 11a of the first fabric base material
11. The taper-corresponding portion 31c has the same width and
length as the taper-corresponding portion 11c of the first fabric
base material 11.
[0088] When manufacturing the tubular fiber structure 10, a jig 51
similar to that of the first embodiment is used. First, the
tube-corresponding portion 31a and the taper-corresponding portion
31c of the second fabric base material 31 are stacked on the
tube-corresponding portion 11a and the taper-corresponding portion
11c of the first fabric base material 11 and rolled around the
inner jig 51b with the second fabric base material 31 located at
the outer side. Then, the outer jig 51a is fitted to the outer side
of the second fabric base material 31, and the first and second
fabric base materials 11 and 31 are held between the outer jig 51a
and the inner jig 51b. Further, in the same manner as the first
embodiment, the flange-corresponding portions 11b projecting from
the two ends of the jig 51 are shaped to form the tubular fiber
structure 10. As a result, in the tube 12 of the obtained tubular
fiber structure 10, a layer in which the layout angles of the
threads serving as the reinforcement fibers are 0 degrees and 90
degrees and a layer in which the layout angles of the threads
serving as the reinforcement fibers are +45 degrees and -45 degrees
are alternately stacked. Further, the tube 12 has an inner diameter
that is fixed and an outer diameter that changes in a stepped
manner so that the thickness changes in a stepped manner from one
end to the other end.
[0089] In addition to advantages (1) to (3) of the first embodiment
and advantage (8) of the fourth embodiment, this embodiment has the
advantages described below.
[0090] (9) The tube 12 of the tubular fiber structure 10 is
tapered. Thus, the energy absorption characteristics are improved
when using the tubular fiber structure 10 as a composite material
for absorbing impacts compared to when the tube 12 has a fixed
diameter and a fixed thickness. More specifically, as shown in the
graph of FIG. 16, the relationship of load and displacement is such
that the displacement gradually increases in proportion to the
compression load and then the displacement increases at a fixed
load.
[0091] (10) The tube 12 has a fixed inner diameter and an outer
diameter that changes in a stepped manner to change the thickness
in a stepped manner from one end to the other end. This tapers the
tube 12. This differs from when rolling a spiral fabric to form a
tapered tube 12 having a fixed thickness in that the density of
fibers does not decrease toward the basal portion (larger diameter
side). Thus, the energy absorption characteristics are further
improved. Further, the first and second fabric base materials 11
and 31 may be formed without using a spiral fiber. This facilitates
manufacturing compared to when using a spiral fabric.
[0092] The embodiments are not limited to the foregoing
description. For example, the technology of the present disclosure
may be embodied as described below.
[0093] As shown in FIG. 17, among the reinforcement threads 16 and
17 forming the flange-corresponding portions 11b of the fabric base
material 11, the threads extending in the circumferential direction
when the flanges 13 are formed, namely, the reinforcement threads
16, may be thicker at the radially outer side of the flange 13
(upper side as viewed in FIG. 17). As a result, the radial layout
density of the reinforcement threads 16 extending in the
circumferential direction of the flange 13 would be greater at
outer positions in the radial direction. In contrast, the
circumferential layout density of the reinforcement threads 17
extending in the radial direction of the flange 13 is smaller at
outer positions in the radial direction. Thus, the difference in
the layout densities of the reinforcement threads 16 and 17 at the
flange 13 may be limited.
[0094] The threads extending in the circumferential direction of
the flange 13, namely, the reinforcement threads 16, may be laid
out so that the layout interval in the radial direction becomes
smaller at outer positions in the radial direction. This also
allows the difference in the layout densities of the reinforcement
threads 16 and 17 at the flange 13 to be limited.
[0095] As shown in FIG. 18, a tubular fiber structure 10 in which
the tube 12 is tapered, may have a structure in which the tube 12
has a fixed thickness and the diameter of the tube 12 gradually
changes from one end to the other end. This tubular fiber structure
10 may be manufactured by using a spiral fabric as the fabric base
material. FIG. 18 does not show overlapping portions of the fabric
base material. The term "tapered" includes a case in which the tube
has a fixed thickness and a diameter that gradually changes from
one end to the other end and also a case in which the tube has a
fixed inner diameter and a gradually changing outer diameter that
changes the thickness in a stepped manner from one end to the other
end.
[0096] The tube 12 does not have to be tubular or a tapered tube
and may be changed in shape in accordance with the usage purpose of
the tubular fiber structure 10. For example, when using the tubular
fiber structure 10 as a reinforcement for a turbine blade composite
material, the tube 12 may be shaped to have a curved surface that
partially bulges inward, as shown in FIG. 19. In this case,
compared to when formed by a three-axis braid structure, the
reinforcement threads forming the tube 12 have fewer crimps. This
decreases the undulation in the surface when forming the composite
material and limits buckling. Further, the amount of deformation
caused by an external force is small. This allows for the flow of
air currents to be stabilized. Further, when using a ceramic matrix
composite (CMC) as the composite material, breakage may be limited
in the CMC, in which the distortion amount until breakage is small
(brittle).
[0097] As shown in FIG. 20, the tubular fiber structure 10 may
include a positioning tube 26 projecting from the flange 13. When
forming a composite material with the tubular fiber structure 10,
the composite material needs to be fixed when positioned at a
predetermined position to couple the composite material to another
member. As long as the tubular fiber structure 10 includes the
positioning tube 26 that projects from the flange 13, the composite
material may be coupled to a coupled portion at the flange 13 with
the positioning tube 26 fitted to a positioning projection or
positioning recess arranged in the coupled portion. Accordingly,
compared to when the positioning tube does not exist, coupling of
the composite member to a target position is facilitated.
[0098] Referring to FIG. 21B, when arranging the reinforcement
portion 18, which is formed by the fabric base material 21, at the
inner side of the tube 12 like in the second embodiment, the
reinforcement portion 18 may be prepared separately from the fabric
base material 11 that forms the tube 12 and the flanges 13. In this
case, after forming the fabric base material 21 including the fixed
portions 21a, as shown in FIG. 21A, the reinforcement portion 18
may be integrated with the tube 12 at the fixed portions 21a. The
reinforcement portion 18 and the tube 12 are integrated by an
adhesive agent or by stitches. In this case, after the formation of
the tubular fiber structure 10, the reinforcement portion 18 may be
coupled when necessary.
[0099] In the fabric base material 11 including the woven texture
14 and the non-woven texture 15, the structure holding the
reinforcement threads 16 and 17 of the non-woven texture 15 at
predetermined positions does not have to be a structure that forms
a woven texture together with the auxiliary threads 16a and 17a.
For example, as shown in FIG. 22, the reinforcement threads 16 and
the reinforcement threads 17 may be adhered with a binder at the
intersections. The intersections do not all have to be adhered with
the binder as long as the shape may be sustained when handling the
tubular fiber structure 10.
[0100] The fabric base material 11 does not have to include the
tube-corresponding portion 11a, which is formed by the non-woven
texture 15 of the reinforcement threads 16 and 17, and the
flange-corresponding portions 11b, which are formed by the woven
texture 14 of the reinforcement threads 16 and 17. For example, in
the fourth embodiment, the fabric base material 11 may be cut out
from the roll shown in FIG. 23B that is plain-weaved by only the
reinforcement threads 16 and 17. From the same roll, the fabric
base material 31 shown in FIG. 23A may be cut out in which
reinforcement threads 19a are laid out at an angle of +45 degrees
and reinforcement threads 19b are laid out an angle of -45
degrees.
[0101] In the fourth embodiment and the fifth embodiment, the
second fabric base material 31 shown in FIG. 24A formed by
reinforcement threads 19a laid out at an angle of +45 degrees and
reinforcement threads 19b laid out an angle of -45 degrees may be
cut out from a roll shown in FIG. 24B that is formed by adhering
only the reinforcement threads 16 and 17 with a binder. The
intersections of the reinforcement threads 16 and 17 do not all
have to be adhered with the binder as long as the shape may be
sustained when handling the tubular fiber structure 10.
[0102] In the lockstitch formed by the stitching threads 22, the
locking thread 22b that corresponds to the lower thread does not
have to extend straight. For example, like a typical lockstitch
shown in FIG. 25, the piercing thread 22a, which corresponds to the
upper thread, and the locking thread 22b are each returned at the
middle of the fabric base material 11 in the thicknesswise
direction so that the seams are the same at the upper and lower
sides and the seams are each independent.
[0103] When using fibers, such as glass fibers or carbon fibers,
that are non-water-absorptive and have high strength as the
stitching threads 22, the energy absorption characteristics are
improved as compared with when using organic fibers that are
water-absorptive.
[0104] Preferably, ceramic fibers are used as the reinforcement
fibers and the stitching threads 22 when using the tubular fiber
structure 10 with a turbine blade. The composite material is CMC.
Thus, the matrix contracts greatly during molding, and cracks
easily form, especially, at corners. However, when the structure is
three-dimensional, deformation resulting from contraction is
reduced, and cracks formed during molding are limited.
[0105] The reinforcement portion 18 does not have to be a
plate-like structure that extends in the radial direction of the
tube 12. For example, the reinforcement portion 18 may be formed by
a fabric base material that is bent in an undulated manner or be
formed by rolling a fabric base material in a tubular manner.
[0106] The tubular fiber structure 10 is not limited to an energy
absorption member that supports a vehicle bumper or a turbine plate
and may be used as a reinforcement for a fiber reinforced composite
material used for a different purpose.
* * * * *