SPINNING UNIT AND SPUN YARN MANUFACTURING METHOD
BACKGROUND OF THE INVENTION
1. Field of the Invention
5 The present invention relates mainly to a spinning
unit that performs spinning using air.
2. Description of the Related Art
The spinning unit that performs spinning using air
10 includes a draft device and a pneumatic spinning device.
The draft device drafts a fiber bundle with roller pairs.
The pneumatic spinning device includes a nozzle block
and a hollow guide shaft body. A spinning nozzle is
formed in the nozzle block. By ejection of compressed
15 air from the spinning nozzle, whirling airflow is
generated. This whirling airflow causes an end of fibers
of the fiber bundle to be reversed and whirled around
the hollow guide shaft body. The reversed fibers wind
around core fibers. This fiber bundle advances towards
20 downstream through a passage inside the hollow guide
shaft body, and is sent downstream as a spun yarn.
Patent Documents 1 to 3 disclose this type of spinning
method.
Japanese Patent Laid-Open No. 2003-193338 (Patent
3
Document 1) describes that a through hole for inserting
a hollow guide shaft body is formed in a nozzle block.
Patent Document 1 describes that an inner diameter of
the most upstream cylindrical space of the through hole
5 is made 4 mm to 6 mm.
Japanese Patent Laid-Open No. H3-241019 (Patent
Document 2) describes that a distance (first distance)
from an inlet of a spindle (hollow guide shaft body) to
a front roller is made 16.5 mm, 20.5 mm, and 24.5 mm.
10 Patent Document 2 describes that a diameter of a nozzle
block is made 7 mm. The nozzle block of Patent Document
2 is a member provided only upstream relative to the
spindle. The spindle described in Patent Document 2 is
rotatably attached about a shaft.
15 Japanese Patent Laid-Open No. 2009-1934 (Patent
Document 3) describes that winding fibers reversed by
whirling airflow go substantially one round along an
inner periphery wall surface of the nozzle block.
In the conventional spinning method, depending on
20 the position where whirling airflow is generated, its
strength, and the like, a strong tension is applied to
winding fibers, and the winding fibers sometimes wind
partially (locally) around the core fibers with a strong
force. Furthermore, in the conventional spinning method,
4
the winding fibers supplied into a whirling chamber
overlaps with the winding fibers supplied next, whereby
the winding fibers sometimes wind partially around the
core fibers with a strong force as well. Such a spun
5 yarn has a hard texture because the winding fibers are
wound partially around with a strong force. Furthermore,
the winding fibers and the core fibers separately exist
on the surface of the spun yarn, and since the winding
fibers and the core fibers have different light
10 reflection modes, the appearance of the spun yarn becomes
non-uniform. The conditions given in Patent Documents 1
to 3 are not sufficient to uniformly wind the winding
fibers around the core fibers.
15 BRIEF SUMMARY OF THE INVENTION
A main object of the present invention is to
provide a spinning unit that can form a spun yarn having
a soft texture and a uniform appearance.
A spinning unit comprises: a draft device
20 configured to include a front roller pair adapted to nip
and deliver a fiber bundle, the draft device being
adapted to draft the fiber bundle; and a pneumatic
spinning device adapted to apply whirling airflow to the
fiber bundle delivered by the draft device thereby
5
forming a spun yarn, wherein the pneumatic spinning
device includes, a nozzle block in which a spinning
nozzle or ejecting air and an inner wall surface forming
a cylindrical whirling chamber re formed, and whirling
5 airflow being generated in the whirling chamber by the
air ejected from the spinning nozzle, and a hollow guide
shaft body through which the fiber bundle having passed
through the whirling chamber passes inside, the hollow
guide shaft body being attached such that rotation about
10 a shaft center of the pneumatic spinning device is
restricted during spinning, the inner wall surface is
entirely provided in a state of being parallel to the
shaft center, a first distance, which is a distance from
a nip point of the front roller pair to an upstream end
15 of the hollow guide shaft body in a fiber travelling
direction, is equal to or less than a perimeter of the
whirling chamber, when viewed at the shaft center, a
nozzle center line of the spinning nozzle is in contact
with the inner wall surface, or, by performing a parallel
20 movement equal to or less than a radius of the spinning
nozzle radially outwards, comes into contact with the
inner wall surface, and a diameter of the whirling
chamber at a position where an ejection port of the
spinning nozzle is formed is equal to or greater than
6
6.7 mm and is less than 9.0 mm.
A spun yarn manufacturing method comprises: a
drafting process in which a fiber bundle is drafted by
using a draft device configured to include a front roller
5 pair that nips and delivers a fiber bundle, and a
spinning process in which a spun yarn is formed by using
a pneumatic spinning device that applies whirling
airflow to the fiber bundle delivered by the draft device,
wherein the pneumatic spinning device includes, a nozzle
10 block in which a spinning nozzle for ejecting air and an
inner wall surface forming a cylindrical whirling
chamber are formed, and whirling airflow being generated
in the whirling chamber by the air ejected from the
spinning nozzle, and a hollow guide shaft body through
15 which the fiber bundle having passed through the whirling
chamber passes inside, the hollow guide shaft body being
attached such that rotation about a shaft center of the
pneumatic spinning device is restricted during spinning,
the inner wall surface is entirely provided in a state
20 of being parallel to the shaft center, a first distance,
which is a distance from a nip point of the front roller
pair to an upstream end of the hollow guide shaft body
in a fiber travelling direction, is equal to or less
than a perimeter of the whirling chamber, when viewed at
7
the shaft center, a nozzle center line of the spinning
nozzle is in contact with the inner wall surface, or, by
performing a parallel movement equal to or less than a
radius of the spinning nozzle to a side of the shaft
5 center, comes into contact with the inner wall surface,
and a diameter of the whirling chamber at a position
where an ejection port of the spinning nozzle is formed
is equal to or greater than 6.7 mm and is less than 9.0
mm.
10
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view illustrating the entire
configuration of a spinning machine including a spinning
unit according to an embodiment of the present invention;
15 FIG. 2 is a side view of the spinning unit;
FIG. 3 is a cross-sectional view illustrating the
configuration of a pneumatic spinning device;
FIG. 4 is a schematic view of a spun yarn formed
by a conventional spinning method;
20 FIG. 5 is a cross-sectional view (plan crosssectional view) of the pneumatic spinning device as
viewed in an axial direction;
FIG. 6 is a cross-sectional view illustrating the
size and angle of each section of the draft device and
8
the pneumatic spinning device; and
FIG. 7 is a schematic view of a spun yarn formed
by a spinning method of the present embodiment.
5 DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Next, a spinning machine 1 including a spinning
unit 2 according to an embodiment of the present
invention will be described with reference to the
drawings. The spinning machine 1 illustrated in FIG. 1
10 includes a multitude of the spinning units 2 arranged
side-by-side, a yarn joining cart 3, a motor box 4, and
a machine control device 90.
The machine control device 90, which is a device
that intensively manages each component of the spinning
15 machine 1, includes a monitor 91 and an input key 92.
The operator performs an appropriate operation using the
input key 92, whereby it is possible to perform setting
of a specific spinning unit 2 or all the spinning units
2 and to display the setting and the status, etc. of the
20 specific spinning unit 2 or all the spinning units 2 on
the monitor 91.
As illustrated in FIG. 2, each spinning unit 2
includes a draft device 7, a pneumatic spinning device
9, a yarn accumulating device 14, and a winding device
9
96 arranged in order from upstream to downstream. In
the present description, “upstream” and “downstream”
mean upstream and downstream in the travelling (passing)
direction of a fiber bundle 8 and a spun yarn 10 at the
5 time of spinning, or in a flow direction of the
compressed air to be ejected. Each spinning unit 2 spins,
with the pneumatic spinning device 9, the fiber bundle
8 sent from the draft device 7, thereby forming the spun
yarn 10, and winds, with the winding device 96, the spun
10 yarn 10, thereby forming a package 28.
The draft device 7 is provided in a vicinity of an
upper end of a housing 5 of the spinning machine 1. The
draft device 7 includes four roller pairs, i.e., a back
roller pair 21, a third roller pair 22, a middle roller
15 pair 24 provided with an apron belt 23, and a front
roller pair 25 in order from upstream. The draft device
7 drafts, to a predetermined thickness, the fiber bundle
8 (sliver) (stretches the fiber bundle 8) supplied from
a sliver case not illustrated via a sliver guide 20.
20 Specifically, the draft device 7 rotates the roller pairs
while nipping the fiber bundle 8 with each roller pair.
The fiber bundle 8 drafted by the draft device 7 is
supplied to the pneumatic spinning device 9.
Hereinafter, a portion where the front roller pair 25
10
nips the fiber bundle 8 is referred to as a nip point.
The pneumatic spinning device 9 forms the spun yarn
10 by using the fiber bundle 8 supplied from the draft
device 7. Specifically, as illustrated in FIG. 3, the
5 pneumatic spinning device 9 includes a fiber guiding
member 31, a needle-shaped member 32, a nozzle block 33,
and a hollow guide shaft body 40.
The fiber guiding member 31 guides, towards inside
the pneumatic spinning device 9, the fiber bundle 8
10 drafted by the draft device 7. The needle-shaped member
32 is attached to the fiber guiding member 31. The fiber
bundle 8 drafted by the draft device 7 is introduced
into the fiber guiding member 31 and guided so as to be
wound around the needle-shaped member 32. A first plane
15 31a is formed on a downstream end of the fiber guiding
member 31. The first plane 31a has a plane shape and
has an opening for arranging the needle-shaped member 32
and passing the fiber bundle 8 through.
The nozzle block 33 is arranged downstream of the
20 fiber guiding member 31. The nozzle block 33 has a
hollow portion, and the fiber bundle 8 passes through
this hollow portion. Specifically, the nozzle block 33
has a whirling chamber 34, which is a cylindrical space.
The nozzle block 33 has an inner wall surface 35, which
11
is a curved surface along the circumferential direction
of the whirling chamber 34. The first plane 31a of the
fiber guiding member 31 forms an upstream end of the
whirling chamber 34.
5 A shaft center of the whirling chamber 34 coincides
with a shaft center of the hollow guide shaft body 40.
Hereinafter, these shaft centers (i.e., a shaft center
of the pneumatic spinning device 9) may be simply
referred to as the shaft center. In the present
10 embodiment, the shaft center of the whirling chamber 34
coincides with the shaft center of the fiber guiding
member 31. The shaft center of the whirling chamber 34
also coincides with the shaft center of the needle-shaped
member 32.
15 A spinning nozzle 37 is formed in the nozzle block
33. The spinning nozzle 37 is formed so that an ejection
port 37a, which is an air ejection side, faces the
whirling chamber 34. The pneumatic spinning device 9
ejects compressed air from the spinning nozzle 37 into
20 the whirling chamber 34, and applies whirling airflow to
the fiber bundle 8 in the whirling chamber 34.
The fiber bundle 8 includes a multitude of fibers.
Some fibers included in the fiber bundle 8 are in a
continuous state between the nip point of the front
12
roller pair 25 and the hollow guide shaft body 40. The
fibers in this state are referred to as core fibers 8a.
Other fibers included in the fiber bundle 8 are not in
a continuous state between the nip point of the front
5 roller pair 25 and the hollow guide shaft body 40. In
other words, the other fibers are arranged such that an
upstream end is positioned downstream relative to the
nip point of the front roller pair 25 and a downstream
end is positioned inside the hollow guide shaft body 40.
10 The downstream end of this type of fibers is twisted
into the core fibers 8a, but the upstream end is a free
end. The free end of each fiber introduced into the
pneumatic spinning device 9 whirls downstream by the
whirling airflow generated by the compressed air ejected
15 from the spinning nozzle 37. In this manner, the free
end (upstream end) of each fiber is caused to flow
downstream, whereby the orientation of the free end is
“reversed” and faces downstream (lower side in FIG. 3).
These reversed fibers wind around the core fibers 8a as
20 described later, and thus the reversed fibers are
referred to as winding fibers 8b. Since the fiber bundle
8 sequentially moves downstream while being spun, one
fiber is the core fiber 8a at the time point of being
nipped by the front roller pair 25, and changes to the
13
winding fiber 8b at the time point of being released
from the nip.
The free end of the winding fibers 8b is subjected
to the action of whirling airflow spirally flowing around
5 the hollow guide shaft body 40 in the whirling chamber
34. Accordingly, the winding fibers 8b whirl around the
outer surface (taper surface) of the hollow guide shaft
body 40. Accordingly, the winding fibers 8b are
sequentially wound around the core fibers 8a.
10 The core fibers 8a are twisted along with the
whirling winding fibers 8b. In this manner, the winding
fibers 8b are wound around the core fibers 8a, and the
core fibers 8a are further twisted, whereby the winding
fibers 8b are twisted into the core fibers 8a, thereby
15 forming the spun yarn 10.
Although the twists of the core fibers 8a tend to
propagate upstream (front roller pair 25 side), the
propagation is blocked by the needle-shaped member 32.
Thus, the needle-shaped member 32 has a function as a
20 twist propagation prevention means.
A taper surface 38 is formed on the nozzle block
33 so as to be connected to the downstream end of the
inner wall surface 35. The taper surface 38 is a surface
whose diameter increases towards downstream. Forming
14
the taper surface 38 makes it possible to secure an
interval between the nozzle block 33 and the hollow guide
shaft body 40. Accordingly, compressed air supplied to
the whirling chamber 34 can be discharged.
5 The hollow guide shaft body 40 is a hollow member,
and a second passage 40a is formed inside thereof. The
hollow guide shaft body 40 is arranged so as to face the
fiber guiding member 31. The hollow guide shaft body 40
is attached to an attachment portion 41 so that rotation
10 about the shaft center is restricted (blocked) during
spinning. The attachment portion 41 is configured to
press the outer surface of the hollow guide shaft body
40 radially inwards, or is configured to interfere with
a part of the hollow guide shaft body 40 and to prevent
15 the hollow guide shaft body 40 from rotating even if a
force in the rotation direction is applied to the hollow
guide shaft body 40. When the hollow guide shaft body
40 is such a non-rotation type, the fiber bundle 8 may
be less likely to be twisted as compared with the
20 rotation type as in Patent Document 2. Therefore, the
pneumatic spinning device 9 is preferably configured to
be capable of sufficiently twisting the fiber bundle 8.
The twisted fiber bundle 8 is guided downstream through
the second passage 40a, and delivered to the outside of
15
the pneumatic spinning device 9 as the spun yarn 10 from
a yarn discharge port (not illustrated).
A yarn quality measuring instrument 12 and a
spinning sensor 13 are provided downstream of the
5 pneumatic spinning device 9. The spun yarn 10 spun by
the pneumatic spinning device 9 passes through the yarn
quality measuring instrument 12 and the spinning sensor
13.
The yarn quality measuring instrument 12 monitors
10 a thickness of the traveling spun yarn 10 by an optical
sensor not illustrated. When detecting a yarn defect of
the spun yarn 10 (where abnormality is present in
thickness or the like of the spun yarn 10), the yarn
quality measuring instrument 12 transmits a yarn defect
15 detection signal to a unit controller not illustrated.
The yarn quality measuring instrument 12 is not limited
to an optical sensor, and may be configured to monitor
the thickness of the spun yarn 10 by using a capacitance
sensor, for example. The yarn quality measuring
20 instrument 12 may detect a foreign substance included in
the spun yarn 10 as a yarn defect.
The spinning sensor 13 is arranged immediately
downstream of the yarn quality measuring instrument 12.
The spinning sensor 13 can detect a tension of the spun
16
yarn 10 between the pneumatic spinning device 9 and the
yarn accumulating device 14. The spinning sensor 13
transmits a detection signal of the detected tension to
the unit controller. The unit controller detects an
5 abnormal portion such as a weak yarn by monitoring the
tension detected by the spinning sensor 13. The spinning
unit 2 does not have to include the spinning sensor 13.
The yarn accumulating device 14 is provided
downstream of the yarn quality measuring instrument 12
10 and the spinning sensor 13. As illustrated in FIG. 2,
the yarn accumulating device 14 includes a yarn
accumulating roller 15 and a motor 16 that rotationally
drives the yarn accumulating roller 15.
The yarn accumulating roller 15 can wind a certain
15 amount of the spun yarn 10 around its outer peripheral
surface and temporarily accumulate the spun yarn 10. By
rotating the yarn accumulating roller 15 at a
predetermined rotation speed with the spun yarn 10 wound
around the outer peripheral surface of the yarn
20 accumulating roller 15, it is possible to pull out the
spun yarn 10 from the pneumatic spinning device 9 at a
predetermined speed and to convey it downstream. Since
the spun yarn 10 can be temporarily accumulated on the
outer peripheral surface of the yarn accumulating roller
17
15, the yarn accumulating device 14 can function as a
kind of buffer. Accordingly, it is possible to eliminate
a defect (such as slack of the spun yarn 10) caused by
disagreement between the spinning speed in the pneumatic
5 spinning device 9 and the winding speed (speed of the
spun yarn 10 to be wound around the package 28) for some
reason.
The winding device 96 includes a cradle arm 97, a
winding drum 98, a traverse guide 99, and a winding drum
10 drive motor not illustrated. The cradle arm 97 can
rotatably support a bobbin for winding the spun yarn 10.
By a drive force of the winding drum drive motor being
transmitted, the winding drum 98 rotates in a state of
being in contact with the outer peripheral surface of
15 the bobbin or the package 28. The traverse guide 99 is
capable of guiding the spun yarn 10. While reciprocating
the traverse guide 99 by a driving means not illustrated,
the winding device 96 drives the winding drum 98 with
the winding drum drive motor. Accordingly, the winding
20 device 96 rotates the package 28 in contact with the
winding drum 98, and winds the spun yarn 10 around the
package 28 while traversing the spun yarn 10.
As illustrated in FIGS. 1 and 2, the yarn joining
cart 3 includes a yarn joining device 93, a suction pipe
18
94, and a suction mouth 95. When yarn breakage or yarn
cutting occurs in a certain spinning unit 2, the yarn
joining cart 3 travels to the relevant spinning unit 2
along a rail not illustrated and stops. The suction
5 pipe 94 rotates upwards about the shaft, catches the
spun yarn 10 delivered from the pneumatic spinning device
9, and rotates downwards about the shaft, thereby guiding
the spun yarn 10 to the yarn joining device 93. The
suction mouth 95 rotates downwards about the shaft,
10 catches the spun yarn 10 from the package 28, and rotates
upwards about the shaft, thereby guiding the spun yarn
10 to the yarn joining device 93. The yarn joining
device 93 joins the guided spun yarns 10 together.
Next, conventional spinning and its problems will
15 be described with reference to FIG. 4. In spinning using
a conventional pneumatic spinning device, a strong
whirling airflow may partially occur mainly around the
outer surface of the hollow guide shaft body (vicinity
of the upstream end in particular). As a result, the
20 winding fibers 8b may concentrate in the vicinity of the
outer surface of the hollow guide shaft body, and the
winding fibers 8b sometimes partially wind around the
core fibers 8a with a strong force (FIG. 4). The partial
winding is a state in which in the longitudinal direction
19
of the spun yarn 10, a portion where the winding fibers
8b are wound and a portion where the winding fibers 8b
are not wound are clearly separated. Even when the
winding fibers 8b whirl along the inner wall surface of
5 the whirling chamber, the winding fibers 8b sometimes
overlap and get entangled with the winding fibers 8b
supplied next. As a result, the winding fibers 8b are
less likely to disperse, and hence the winding fibers 8b
partially wind around the core fibers 8a with a strong
10 force.
Such a spun yarn 10 has a hard texture because the
winding fibers 8b are partially wound around with a
strong force. Furthermore, the winding fibers 8b and
the core fibers 8a separately exist on the surface of
15 the spun yarn 10. The winding fibers 8b and the core
fibers 8a have different light reflection modes because
the orientations of the fibers are different. As a
result, the appearance of the spun yarn 10 becomes nonuniform.
20 Next, the detailed shape of the pneumatic spinning
device 9, the positional relationship with the draft
device 7, and the like will be described with reference
to mainly FIGS. 5 and 6. In the following description,
the terms indicating angles such as parallel and
20
perpendicular include not only strict parallel and the
like but also substantially parallel and the like. As
the range of substantially parallel and the like, the
error is assumed to be ±3° or ±5°, for example. The
5 terms such as circular, straight line, tangent line, and
entirely include not only strict circular and the like
but also substantially circular and the like.
The pneumatic spinning device 9 of the present
embodiment has two main features as compared with the
10 conventional pneumatic spinning device. The first
feature is that whirling airflow along the inner wall
surface 35 of the whirling chamber 34 can be generated,
and further, whirling airflow can also be generated
upstream in the fiber travelling direction relative to
15 the ejection port 37a. The second feature is that the
winding fibers 8b do not overlap with the winding fibers
8b supplied next.
First, the configuration of the pneumatic spinning
device 9 for exerting the first feature will be described.
20 As illustrated in FIG. 5, four spinning nozzles 37
are formed in the nozzle block 33. The spinning nozzles
37 are formed at 90° intervals with respect to the shaft
center (i.e., are formed so that the angles between the
spinning nozzles 37 are equal).
21
In order to generate whirling airflow along the
inner wall surface 35, the spinning nozzle 37 is formed
along the inner wall surface 35. Specifically, the
spinning nozzle 37 is linear and has a circular cross
5 section, and the radially outermost portion of the wall
surface of the spinning nozzle 37 (hereinafter, a wall
surface 37b) is formed so as to contact the circular
inner wall surface 35. Hereinafter, this tangent line
is referred to as a nozzle tangent line 101. The center
10 line of the spinning nozzle 37 is referred to as a nozzle
center line 102. The nozzle tangent line 101 and the
nozzle center line 102 are parallel to each other, and
the distance between the nozzle tangent line 101 and the
nozzle center line 102 is referred to as a third distance
15 L3. In the present embodiment, the wall surface 37b and
the nozzle tangent line 101 coincide with each other,
and hence the third distance L3 coincides with the radius
of the spinning nozzle 37.
The spinning nozzle 37 may be formed at a position
20 slightly away from the shaft center as compared with
that in the present embodiment. For example, the
spinning nozzle 37 may be formed so that the nozzle
tangent line 101 and the nozzle center line 102 coincide
with each other. That is, the nozzle tangent line 101
22
and the nozzle center line 102 may coincide with each
other, or the nozzle center line 102 may be positioned
on the shaft center side relative to the nozzle tangent
line 101, and the third distance L3 may be any value of
5 equal to or greater than 0 and equal to or less than the
radius of the spinning nozzle 37. In other words, when
viewed in the shaft center direction (i.e., in FIG. 5),
the nozzle center line 102 of the spinning nozzle 37 is
in contact with the inner wall surface 35, or, by
10 performing a parallel movement of equal to or less than
the radius of the spinning nozzle 37 radially outwards,
comes into contact with the inner wall surface 35.
In this manner, by forming the spinning nozzle 37
to be along the inner wall surface 35, whirling airflow
15 along the inner wall surface 35 can be generated. By
applying whirling airflow along the inner wall surface
35 to the winding fibers 8b, the winding fibers 8b whirl
along the inner wall surface 35, and hence it is possible
to reduce the tension applied to the winding fibers 8b
20 while dispersing the winding fibers 8b. Accordingly,
the winding fibers 8b are likely to be uniformly wound
around the core fibers 8a.
Furthermore, the plurality of spinning nozzles 37
are formed as in the present embodiment, whereby the air
23
ejected from the ejection port 37a is exposed to the air
ejected from another ejection port 37a. Therefore,
whirling airflow can also be generated upstream in the
fiber travelling direction relative to the ejection port
5 37a. As a result, whirling airflow along the inner wall
surface 35 can be generated in a wide range of the
whirling chamber 34. However, when the number of
spinning nozzles 37 is too large, the air ejected from
the ejection ports 37a may interfere with each other and
10 turbulence may occur in the whirling airflow. For this
reason, the number of spinning nozzles 37 (ejection ports
37a) is preferably equal to or greater than 3 and equal
to or less than 6. However, the number of spinning
nozzles 37 may be equal to or less than 2 or equal to or
15 greater than 7. The spinning nozzle 37 does not have to
be linear. In this case, the center line in the vicinity
of the ejection port 37a is regarded as the nozzle center
line 102.
Furthermore, in order to exert the first feature,
20 the whirling chamber 34 is one cylindrical space having
a constant diameter. Therefore, the entire inner wall
surface 35 is parallel with the shaft center. In other
words, in a cross section cut with any plane parallel to
the shaft center (e.g., FIG. 6), an angle formed by a
24
shaft center line 103 indicating the position of the
shaft center and an imaginary extension line of the inner
wall surface 35 is 0°. The angle formed by the shaft
center line 103 and the imaginary extension line of the
5 inner wall surface 35 may be any value equal to or less
than 1.5°. For example, when the inner wall surface 35
is inclined so as to expand towards downstream, the shaft
center line 103 and the imaginary extension line of the
inner wall surface 35 intersect upstream relative to the
10 inner wall surface 35. The smaller of the angles formed
by these two straight lines is the angle formed by the
two straight lines. On the other hand, when the inner
wall surface 35 is inclined so as to expand towards
upstream, the shaft center line 103 and the imaginary
15 extension line of the inner wall surface 35 intersect
downstream relative to the inner wall surface 35. The
smaller of the angles formed by these two straight lines
is the angle formed by the two straight lines. In either
case, the angle formed is equal to 0° or a positive value
20 greater than 0° and less than 90°.
When a step or a taper is formed in the whirling
chamber, even if the whirling airflow is along the inner
wall surface in the vicinity of the ejection port, the
whirling airflow is separated from the inner wall surface
25
or turbulence generates as the whirling airflow moves
away from the ejection port. In this regard, since in
the present embodiment, the diameter of the whirling
chamber 34 is constant, whirling airflow along the inner
5 wall surface 35 can be generated over the entire fiber
travelling direction.
The above configuration allows the whirling
chamber 34 to exert the first feature described above.
In order to apply such whirling airflow along the inner
10 wall surface 35 to the winding fibers 8b, the pneumatic
spinning device 9 further has a condition regarding the
second distance and a condition regarding an effective
length h.
The second distance L2 is a component of the
15 distance in a direction parallel to the shaft center
from the downstream end (first plane 31a) of the fiber
guiding member 31 to the upstream end of the hollow guide
shaft body 40. If the second distance L2 is too short,
the winding fibers 8b are less likely reversed. If the
20 second distance L2 is too long, the distance from the
nip point to the hollow guide shaft body 40 becomes long,
and hence the fibers included in the fiber bundle 8 are
more likely to fall off. Therefore, in the present
embodiment, the second distance L2 is preferably equal
26
to or greater than 0.3 mm, and is preferably equal to or
less than 2.0 mm, equal to or less than 3.0 mm, equal to
or less than 5.0 mm, or equal to or less than 7.0 mm.
The whirling chamber 34 of the present embodiment is
5 formed so as to be located not only upstream relative to
the upstream end of the hollow guide shaft body 40 but
also downstream relative to the upstream end of the
hollow guide shaft body 40.
The effective length h is a length (length along
10 the shaft center) in which the whirling airflow can be
applied to the winding fibers 8b. Although the whirling
airflow is also present upstream relative to the ejection
port 37a as described above, the whirling airflow mainly
exist downstream relative to the ejection port 37a.
15 Therefore, the effective length h is a length along the
shaft center from the ejection port 37a to the downstream
end of the whirling chamber 34 in the fiber travelling
direction. The effective length h is determined so that
the whirling airflow flows at least half round and at
20 most one round in the whirling chamber 34.
Specifically, the effective length h is
represented by using the nozzle angle θ. The nozzle
angle θ is the smaller angle of the angles formed by
the imaginary plane 104 perpendicular to the shaft center
27
and the nozzle center line 102 intersecting with each
other when viewed in the radial direction of the whirling
chamber 34 (i.e., in FIG. 6) (angle formed by an
imaginary plane 104 and the nozzle center line 102).
5 Assuming that the diameter of the whirling chamber 34 is
d, it is preferable that “dπ/2tanθ ≤ h ≤ dπ/tanθ” is
established. When the inner wall surface 35 is not
strictly parallel with the shaft center, it is preferable
to use the diameter d at the position where the ejection
10 port 37a is formed, for example. At the position where
the ejection port 37a is formed, whirling airflow is
generated, and whirling of the winding fibers 8b is also
generated.
dπ is the perimeter of the inner wall surface 35.
15 The whirling airflow flows along the inner wall surface
35 while maintaining the nozzle angle θ. When dπ/2tanθ
= h is established, the whirling airflow flows half round
before reaching the downstream end of the whirling
chamber 34. When dπ/tanθ = h is established, the
20 whirling airflow flows one round before reaching the
downstream end of the whirling chamber 34. Therefore,
when the whirling airflow flows at least half round and
at most one round in the whirling chamber 34, the above
expressions are established. Accordingly, the winding
28
fibers 8b can be whirled within an appropriate range.
Next, the configuration of the pneumatic spinning
device 9 for exerting the second feature will be
described. The second feature is that the winding fibers
5 8b do not overlap with the winding fibers 8b supplied
next.
As illustrated in FIG. 6, the distance from the
nip point of the front roller pair 25 to the upstream
end of the hollow guide shaft body 40 (more specifically,
10 a point that is located on the upstream end and located
on the shaft center) is referred to as a first distance
L1. The first distance L1 is a linear distance, and is
not a distance along an actual travelling path of the
fiber bundle 8. Although the first distance L1 is the
15 length of a line segment in a three-dimensional space,
it can also be expressed as the length of a line segment
in the view (FIG. 6) viewed in the axial direction of
the front roller pair 25. There is a tendency that the
shorter the first distance L1 is, the less the reversed
20 fibers becomes, and the less the amount of fibers that
are wound becomes. Since the amount of fibers that are
wound may affect the quality of the spun yarn 10 even if
the amount of the fibers that are wound is either too
large or too small, an appropriate value is set for the
29
first distance L1 in accordance with the shape of the
nozzle block 33, the nature of the raw material (fiber
bundle 8), and the yarn count of the spun yarn 10 to be
formed. Since the fiber bundle 8 is held at the nip
5 point (of the front roller pair 25 one end of the first
distance L1), the first distance L1 coincides with the
maximum length of the winding fibers 8b. Of the
multitude of fibers included in the fiber bundle 8, most
of single fibers function as the core fibers 8a and the
10 winding fibers 8b in one spun yarn 10, and hence the
length of the winding fibers 8b is shorter than the
length of the single fiber.
In the present embodiment, in order to exert the
second feature (in order to prevent the winding fibers
15 8b from overlapping with the winding fibers 8b supplied
next), the first distance L1 is equal to or less than
the perimeter of the whirling chamber 34. As illustrated
in FIG. 5, the winding fibers 8b whirl along the inner
wall surface 35. By setting the first distance L1 to be
20 equal to or less than the perimeter of the whirling
chamber 34, the length of the winding fibers 8b also
becomes equal to or less than the perimeter of the
whirling chamber 34, and the winding fibers 8b do not go
one round along the inner wall surface 35. Therefore,
30
the winding fibers 8b do not overlap with the winding
fibers 8b supplied next. As a result, the winding fibers
8b are dispersed, and hence the winding fibers 8b can
easily be uniformly wound around the core fibers 8a.
5 Thus, the pneumatic spinning device 9 of the present
embodiment has the second feature.
The first distance L1 is preferably equal to or
greater than 19 mm and equal to or less than 28 mm for
example, and more preferably equal to or greater than 19
10 mm and equal to or less than 21 mm. When the first
distance L1 is 21 mm, if the diameter d of the whirling
chamber 34 is about 6.7 mm, the first distance L1 =
perimeter is established. Therefore, if the diameter d
is equal to or greater than 6.7 mm, the nozzle block 33
15 having the feature can be adopted in a configuration in
which the first distance L1 is equal to or greater than
19 mm and equal to or less than 21 mm. When the first
distance L1 is 28 mm, if the diameter d of the whirling
chamber 34 is about 9.0 mm, the first distance L1 =
20 perimeter is established. Thus, the diameter d is
preferably equal to or greater than 6.7 mm and is less
than 9.0 mm. The diameter d is more preferably equal to
or greater than 7.0 mm and equal to or less than 8.0 mm.
Since the present embodiment has the first and
31
second features described above, the winding fibers 8b
are likely to uniformly wind around the core fibers 8a.
FIG. 7 illustrates a schematic view of the spun yarn 10
formed by the spinning method of the present embodiment.
5 Since a winding force of the winding fibers 8b is soft
and the winding fibers 8b are uniformly wound around the
core fibers 8a in this spun yarn 10, the spun yarn 10
having a soft texture and a uniform appearance can be
formed.
10 As described above, the spinning unit 2 of the
present embodiment includes the draft device 7 and the
pneumatic spinning device 9, and manufactures the spun
yarn 10. The draft device 7 is configured to include
the front roller pair 25 that nips and delivers the fiber
15 bundle 8, and drafts the fiber bundle 8 (drafting
process). The pneumatic spinning device 9 applies
whirling airflow to the fiber bundle 8 delivered by the
draft device 7, thereby forming the spun yarn 10
(spinning process). The pneumatic spinning device 9
20 includes the nozzle block 33 and the hollow guide shaft
body 40. In the nozzle block 33, the spinning nozzle 37
for ejecting air and the inner wall surface 35 forming
the cylindrical whirling chamber 34 are formed, and
whirling airflow is generated in the whirling chamber 34
32
by the air ejected from the spinning nozzle 37. The
fiber bundle 8 having passed through the whirling chamber
34 passes through inside the hollow guide shaft body 40,
and the hollow guide shaft body 40 is attached such that
5 rotation about the shaft center of the pneumatic spinning
device 9 is restricted during spinning. The inner wall
surface 35 is entirely provided in a state of being
parallel to the shaft center. The first distance L1,
which is the distance from the nip point of the front
10 roller pair 25 to the upstream end of the hollow guide
shaft body 40 in the fiber travelling direction, is equal
to or less than the perimeter of the whirling chamber
34. When viewed at the shaft center, the nozzle center
line 102 of the spinning nozzle 37 is in contact with
15 the inner wall surface 35, or, by performing a parallel
movement equal to or less than the radius of the spinning
nozzle 37 radially outwards, comes into contact with the
inner wall surface 35. The diameter d of the whirling
chamber 34 at the position where the ejection port 37a
20 of the spinning nozzle 37 is formed is equal to or
greater than 6.7 mm and is less than 9.0 mm.
Since the nozzle center line 102 and the inner wall
surface 35 have the above-mentioned relationship, and
moreover, the inner wall surface 35 of the whirling
33
chamber 34 is provided in a state of being parallel to
the shaft center, the whirling airflow along the inner
wall surface 35 can be applied to the winding fibers 8b.
Since this causes the winding fibers 8b to whirl along
5 the inner wall surface 35, it is possible to reduce the
tension applied to the winding fibers 8b while dispersing
the winding fibers 8b, as compared with the case where
the winding fibers 8b whirl around an outer surface of
the hollow guide shaft body 40. Since the first distance
10 L1 is equal to or less than the perimeter of the whirling
chamber 34, the winding fibers 8b are less likely to go
one round in the whirling chamber 34, and are hence less
likely to overlap with the winding fibers 8b supplied
next. Also in this regard, the winding fibers 8b are
15 easily dispersed. In consideration of the general first
distance L1, it is more preferable that the diameter d
of the whirling chamber 34 is within the above range.
By the winding fibers 8b being dispersed and the tension
being reduced, the winding fibers 8b are likely to be
20 uniformly wound around the core fibers 8a. As a result,
the spun yarn 10 having a soft texture and a uniform
appearance can be formed.
In the spinning unit 2 of the present embodiment,
in a cross section obtained by cutting with any plane
34
parallel to the shaft center, the shaft center (shaft
center line 103) and the inner wall surface 35 are
parallel to each other, or the angle formed by the shaft
center and an imaginary extension line of the inner wall
5 surface 35 is equal to or less than 1.5°.
Accordingly, since the parallelism between the
shaft center and the inner wall surface 35 is
sufficiently high, whirling airflow along the inner wall
surface 35 with little turbulence can be generated.
10 In the spinning unit 2 of the present embodiment,
regarding the diameter d of the whirling chamber 34, the
nozzle angle θ formed by the imaginary plane 104
perpendicular to the shaft center and the nozzle center
line 102, and the effective length h along the shaft
15 center up to the downstream end of the whirling chamber
34 in the fiber travelling direction from the ejection
port 37a, dπ/2tanθ ≤ h ≤ dπ/tanθ is established.
Accordingly, since the whirling airflow flowing
along the nozzle angle θ flows at least half round and
20 at most one round in the whirling chamber 34, the winding
fibers 8b can be whirled in an appropriate range.
In the spinning unit 2 of the present embodiment,
the pneumatic spinning device 9 includes the fiber
guiding member 31 that guides, towards the whirling
35
chamber 34, the fiber bundle 8 having been delivered by
the draft device 7. The second distance L2, which is a
component in the direction parallel to the shaft center
of the hollow guide shaft body 40 and which is a distance
5 from the downstream end in the fiber travelling direction
of the fiber guiding member 31 to the upstream end in
the fiber travelling direction of the hollow guide shaft
body 40 is equal to or greater than 0.3 mm and equal to
or less than 7.0 mm.
10 This makes it possible to reduce the amount of
fibers falling off while reducing the tension applied to
the winding fibers 8b.
In the spinning unit 2 of the present embodiment,
the number of the spinning nozzles 37 formed in the
15 nozzle block 33 is equal to or greater than 3 and equal
to or less than 6.
Accordingly, since the plurality of spinning
nozzles 37 are formed, the air ejected from one ejection
port 37a is exposed to the air ejected from another
20 ejection port 37a, and hence the whirling airflow can
also be generated upstream in the fiber travelling
direction relative to the ejection port 37a. Therefore,
it is possible to generate whirling airflow along the
inner wall surface 35 in a wide range of the whirling
36
chamber 34. Not providing too many spinning nozzles 37
can reduce turbulence of the whirling airflow.
In the spinning unit 2 of the present embodiment,
the first distance L1 is equal to or greater than 19 mm
5 and equal to or less than 28 mm.
Accordingly, the spinning unit 2 can perform
spinning under various conditions.
While the preferred embodiment of the present
invention has been described above, the configuration
10 described above can be modified as below. The following
modifications can be combined as appropriate.
The needle-shaped member 32 may be omitted, and
the function of the needle-shaped member 32 may be
performed by the downstream end of the fiber guiding
15 member 31.
At a position located downstream of the pneumatic
spinning device 9, instead of or in addition to the yarn
accumulating device 14, a rotationally driven delivery
roller and a nip roller that is pressed against the
20 delivery roller may be provided, and the spun yarn 10
may be sandwiched between the delivery roller and the
nip roller to send the spun yarn 10 downstream. In this
case, a slack tube using suction airflow and/or a
mechanical compensator may be provided downstream of the
37
delivery roller and the nip roller.
Although in the spinning unit 2, each device is
arranged so that the fiber passing direction is from the
upper side to the lower side, each device may be arranged
5 so that the fiber passing direction is from the lower
side to the upper side.
The fiber guiding member 31 and the nozzle block
33 may be integrally configured as a single member.
By reversely conveying the spun yarn 10 from the
10 package 28 to at least the pneumatic spinning device 9,
and then starting the drafting operation by the draft
device 7 and the spinning operation by the pneumatic
spinning device 9, the spinning unit 2 may bring the
spun yarn 10 having been disconnected into a continuous
15 state (so-called piecing).
The spinning machine 1 may not include the yarn
joining cart 3, and each spinning unit 2 may be provided
with a configuration for bringing the spun yarn 10 having
been disconnected into a continuous state.
20 According to the first aspect of the present
invention, a spinning unit configured as follows is
provided. That is, this spinning unit includes the draft
device and the pneumatic spinning device. The draft
device is configured to include a front roller pair that
38
nips and delivers a fiber bundle, and to draft the fiber
bundle. The pneumatic spinning device applies whirling
airflow to the fiber bundle delivered by the draft device,
thereby forming a spun yarn. The pneumatic spinning
5 device includes the nozzle block and the hollow guide
shaft body. In the nozzle block, a spinning nozzle for
ejecting air and an inner wall surface forming a
cylindrical whirling chamber are formed, and whirling
airflow is generated in the whirling chamber by air
10 ejected from the spinning nozzle. The fiber bundle
having passed through the whirling chamber passes
through inside the hollow guide shaft body, and the
hollow guide shaft body is attached such that rotation
about a shaft center of the pneumatic spinning device is
15 restricted during spinning. The inner wall surface is
entirely provided in a state of being parallel to the
shaft center. A first distance, which is the distance
from a nip point of the front roller pair to an upstream
end of the hollow guide shaft body in a fiber travelling
20 direction, is equal to or less than a perimeter of the
whirling chamber. When viewed at the shaft center, a
nozzle center line of the spinning nozzle is in contact
with the inner wall surface, or, by performing a parallel
movement equal to or less than a radius of the spinning
39
nozzle radially outwards, comes into contact with the
inner wall surface. A diameter of the whirling chamber
at a position where an ejection port of the spinning
nozzle is formed is equal to or greater than 6.7 mm and
5 is less than 9.0 mm.
Since the nozzle center line and the inner wall
surface have the above-mentioned relationship, and
moreover, the inner wall surface of the whirling chamber
is provided in a state of being parallel to the shaft
10 center, the whirling airflow along the inner wall surface
can be applied to the winding fibers. Since this causes
the winding fibers to whirl along the inner wall surface,
it is possible to reduce a tension applied to the winding
fibers while dispersing the winding fibers, as compared
15 with the case where the winding fibers whirl around an
outer surface of the hollow guide shaft body. Since the
first distance is equal to or less than the perimeter of
the whirling chamber, the winding fibers are less likely
to go one round in the whirling chamber, and are hence
20 less likely to overlap with winding fibers supplied next.
Also in this regard, the winding fibers are easily
dispersed. In consideration of a general first distance,
it is more preferable that the diameter of the whirling
chamber be within the above range (equal to or greater
40
than 6.7 mm and less than 9.0 mm). By the winding fibers
being dispersed and the tension being reduced, the
winding fibers are likely to be uniformly wound around
the core fibers. As a result, a spun yarn having a soft
5 texture and a uniform appearance can be formed.
In the spinning unit described above, in a cross
section obtained by cutting with any plane parallel to
the shaft center, the shaft center and the inner wall
surface are parallel to each other, or the angle formed
10 by the shaft center and an imaginary extension line of
the inner wall surface is preferably equal to or less
than 1.5°.
Accordingly, since the parallelism between the
shaft center and the inner wall surface sufficiently
15 high, whirling airflow along the inner wall surface with
little turbulence can be generated.
The spinning unit described above preferably has
the following configuration. That is, the diameter of
the whirling chamber is assumed to be d. A nozzle angle,
20 which is the angle formed by a plane perpendicular to
the shaft center and the nozzle center line when viewed
in the radial direction of the whirling chamber, is
assumed to be θ. A length along the shaft center from
the ejection port to the downstream end of the whirling
41
chamber in the fiber travelling direction is assumed to
be h. In this case, dπ/2tanθ ≤ h ≤ dπ/tanθ is
established.
Accordingly, since the whirling airflow flowing
5 along the nozzle angle flows at least half round and at
most one round in the whirling chamber, the winding
fibers can be whirled in an appropriate range.
The spinning unit described above preferably has
the following configuration. That is, the pneumatic
10 spinning device includes a fiber guiding member that
guides, towards the whirling chamber, the fiber bundle
having been delivered by the draft device. A second
distance, which is a component in the direction parallel
to the shaft center of the hollow guide shaft body and
15 which is a distance between downstream end in the fiber
travelling direction of the fiber guiding member and the
upstream end in the fiber travelling direction of the
hollow guide shaft body, is equal to or greater than 0.3
mm and equal to or less than 7.0 mm.
20 This makes it possible to reduce the amount of
fibers falling off while reducing the tension applied to
the winding fibers.
In the spinning unit described above, the number
of the spinning nozzles formed in the nozzle block is
42
preferably equal to or greater than 3 and equal to or
less than 6.
Accordingly, since the plurality of spinning
nozzles are formed, the air ejected from one ejection
5 port is exposed to the air ejected from another ejection
port, and hence whirling airflow can also be generated
upstream in the fiber travelling direction relative to
the ejection port. Therefore, it is possible to generate
whirling airflow along the inner wall surface in a wide
10 range of the whirling chamber. Not providing too many
spinning nozzles can reduce turbulence of the whirling
airflow.
In the spinning unit described above, the first
distance is preferably equal to or greater than 19 mm
15 and equal to or less than 28 mm.
Accordingly, the spinning unit can perform
spinning under various conditions.
According to the second aspect of the present
invention, a spun yarn manufacturing method as follows
20 is provided. That is, this spun yarn manufacturing
method includes a drafting process and a spinning process.
In the drafting process, the fiber bundle is drafted by
using the draft device configured to include the front
roller pair that nips and delivers the fiber bundle. In
43
the spinning process, a spun yarn is formed by using a
pneumatic spinning device that applies whirling airflow
to the fiber bundle delivered by the draft device. The
pneumatic spinning device includes the nozzle block and
5 the hollow guide shaft body. In the nozzle block, the
spinning nozzle for ejecting air and the inner wall
surface forming the cylindrical whirling chamber are
formed, and whirling airflow is generated in the whirling
chamber by the air ejected from the spinning nozzle.
10 The fiber bundle having passed through the whirling
chamber passes through inside the hollow guide shaft
body, and the hollow guide shaft body is attached such
that rotation about a shaft center of the pneumatic
spinning device is restricted during spinning. The
15 inner wall surface is provided in a state of being
parallel to the shaft center. A first distance, which
is the distance from a nip point of the front roller
pair to an upstream end of the hollow guide shaft body
in a fiber travelling direction, is equal to or less
20 than a perimeter of the whirling chamber. When viewed
at the shaft center, a nozzle center line of the spinning
nozzle is in contact with the inner wall surface, or, by
performing a parallel movement equal to or less than a
radius of the spinning nozzle radially outwards, comes
44
into contact with the inner wall surface. A diameter of
the whirling chamber at a position where an ejection
port of the spinning nozzle is formed is equal to or
greater than 6.7 mm and is less than 9.0 mm.
5 Accordingly, a spun yarn having a soft texture and
a uniform appearance can be formed.

WE CLAIM
1. A spinning unit (2), comprising:
a draft device (7) configured to include a front
roller pair (25) adapted to nip and deliver a fiber
5 bundle (8), the draft device (7) being adapted to draft
the fiber bundle (8); and
a pneumatic spinning device (9) adapted to apply
whirling airflow to the fiber bundle (8) delivered by
the draft device (7), thereby forming a spun yarn (10),
10 wherein
the pneumatic spinning device (9) includes,
a nozzle block (33) in which a spinning nozzle (37)
for ejecting air and an inner wall surface (35) forming
a cylindrical whirling chamber (34) are formed, and
15 whirling airflow being generated in the whirling chamber
(34) by the air ejected from the spinning nozzle (37),
and
a hollow guide shaft body (40) through which the
fiber bundle (8) having passed through the whirling
20 chamber (34) passes inside, the hollow guide shaft body
(40) being attached such that rotation about a shaft
center of the pneumatic spinning device (9) is restricted
during spinning,
the inner wall surface (35) is entirely provided
46
in a state of being parallel to the shaft center,
a first distance (L1), which is a distance from a
nip point of the front roller pair (25) to an upstream
end of the hollow guide shaft body (40) in a fiber
5 travelling direction, is equal to or less than a
perimeter of the whirling chamber (34),
when viewed at the shaft center, a nozzle center
line (102) of the spinning nozzle (37) is in contact
with the inner wall surface (35), or, by performing a
10 parallel movement equal to or less than a radius of the
spinning nozzle (37) radially outwards, comes into
contact with the inner wall surface (35), and
a diameter of the whirling chamber (34) at a
position where an ejection port (37a) of the spinning
15 nozzle (37) is formed is equal to or greater than 6.7 mm
and is less than 9.0 mm.
2. The spinning unit (2) as claimed in claim 1,
wherein in a cross section obtained by cutting with any
20 plane parallel to the shaft center, the shaft center and
the inner wall surface (35) are parallel to each other,
or an angle formed by the shaft center and an imaginary
extension line of the inner wall surface (35) is equal
to or less than 1.5°.
47
3. The spinning unit (2) as claimed in claim 1 or
2, wherein assuming that a diameter of the whirling
chamber (34) is d, and a nozzle angle, which is an angle
5 formed by a plane perpendicular to the shaft center and
the nozzle center line (102) when viewed in a radial
direction of the whirling chamber (34), is θ, and a
length along the shaft center from the ejection port
(37a) to a downstream end of the whirling chamber (34)
10 in a fiber travelling direction is h, dπ/2tanθ ≤ h ≤
dπ/tanθ is established.
4. The spinning unit (2) as claimed in any one of
claims 1 to 3, wherein
15 the pneumatic spinning device (9) includes a fiber
guiding member (31) adapted to guide, towards the
whirling chamber (34), the fiber bundle (8) having been
delivered by the draft device (7), and
a second distance (L2), which is a component in a
20 direction parallel to a shaft center of the hollow guide
shaft body (40) and which is a distance from a downstream
end in a fiber travelling direction of the fiber guiding
member (31) to an upstream end in a fiber travelling
direction of the hollow guide shaft body (40), is equal
48
to or greater than 0.3 mm and equal to or less than 7.0
mm.
5. The spinning unit (2) as claimed in any one of
5 claims 1 to 4, wherein the number of the spinning nozzles
(37) formed in the nozzle block (33) is equal to or
greater than 3 and equal to or less than 6.
6. The spinning unit (2) as claimed in any one of
10 claims 1 to 5, wherein the first distance (L1) is equal
to or greater than 19 mm and equal to or less than 28
mm.
7. A spun yarn (10) manufacturing method,
15 comprising:
a drafting process in which a fiber bundle (8) is
drafted by using a draft device (7) configured to include
a front roller pair (25) that nips and delivers a fiber
bundle (8), and
20 a spinning process in which a spun yarn (10) is
formed by using a pneumatic spinning device (9) that
applies whirling airflow to the fiber bundle (8)
delivered by the draft device (7), wherein
the pneumatic spinning device (9) includes,
49
a nozzle block (33) in which a spinning nozzle (37)
for ejecting air and an inner wall surface (35) forming
a cylindrical whirling chamber (34) are formed, and
whirling airflow being generated in the whirling chamber
5 (34) by the air ejected from the spinning nozzle (37),
and
a hollow guide shaft body (40) through which the
fiber bundle (8) having passed through the whirling
chamber (34) passes inside, the hollow guide shaft body
10 (40) being attached such that rotation about a shaft
center of the pneumatic spinning device (9) is restricted
during spinning,
the inner wall surface (35) is entirely provided
in a state of being parallel to the shaft center,
15 a first distance (L1), which is a distance from a
nip point of the front roller pair (25) to an upstream
end of the hollow guide shaft body (40) in a fiber
travelling direction, is equal to or less than a
perimeter of the whirling chamber (34),
20 when viewed at the shaft center, a nozzle center
line (102) of the spinning nozzle (37) is in contact
with the inner wall surface (35), or, by performing a
parallel movement equal to or less than a radius of the
spinning nozzle (37) to a side of the shaft center, comes
50
into contact with the inner wall surface (35), and
a diameter of the whirling chamber (34) at a
position where an ejection port (37a) of the spinning
nozzle (37) is formed is equal to or greater than 6.7 mm
5 and is less than 9.0 mm.