TECHNICAL FIELD
[0001] The present invention mainly relates to an air spinning device for spinning by using air.
BACKGROUND ART
[0002] An air spinning device adapted to form a spun yarn by applying twists to fibers by an action of a swirling airflow current that is formed in a spinning chamber, has been conventionally known. PTL 1 discloses this kind of air spinning device.
[0003] The air spinning device disclosed in PTL 1 has a nozzle cap for fixing a fiber guide and a nozzle block to a nozzle holder, which can prevent deviation of a fixing position of the fiber guide and the nozzle block. Thereby, variation in a shape of a spinning chamber is reduced.
CITATION LIST PATENT LITERATURE
[0004] PTL 1: Japanese Patent Application Laid-Open No. 2012-127009
SUMMARY OF THE INVENTION
[0005] An object of the present invention is to provide an air spinning device capable of spinning a spun yarn with higher quality, an air spinning machine having the air spinning device, and a spinning method using the air spinning device.
[0006] According to a first aspect of the present invention, an air spinning device with the following configuration is provided. That is, the air spinning device forms a yarn by applying twists to a fiber bundle using a swirling airflow current. The air spinning device includes a fiber guide, a nozzle block,

and an inflow chamber forming block. The fiber guide guides the fiber bundle. The nozzle block
has a nozzle through which a compressed air passes, the compressed air for generating the swirling
airflow current to be acted on the fiber bundle that has been guided by the fiber guide. The inflow
chamber forming block has an inflow chamber into which the swirling airflow current flows. The
inflow chamber has a portion whose diameter is 25 mm or more and 36 mm or less.
[0007] Accordingly, the inflow chamber capable of easily collecting fiber waste can be formed. As
a result, each fiber contained in the fiber bundle can be smoothly swirled by an action of the swirling
airflow current, and a yarn with high quality can be formed.
[0008] In the air spinning device, the inflow chamber preferably has a portion whose diameter is 28
mm or more and less than 34 mm.
[0009] Accordingly, the fiber waste can be further easily collected.
[0010] The air spinning device is preferably configured as follows. That is, the length of the inflow
chamber in its axial direction is 38% or more and 75% or less of the diameter of the inflow chamber.
[0011] Accordingly, the inflow chamber with a preferable shape can be realized.
[0012] In the air spinning device, the length of the inflow chamber in its axial direction is preferably
14 mm or more and 25 mm or less.
[0013] Accordingly, the inflow chamber with an appropriate size can be formed.
[0014] In the air spinning device, the inflow chamber is preferably connected to an exhaust passage,
which exhausts the swirling airflow current, via a connection opening formed in the inflow chamber
forming block.
[0015] Accordingly, the air can be exhausted from the inflow chamber. The fiber waste collected
in the inflow chamber can be easily discharged.
[0016] The air spinning device is preferably configured as follows. That is, in the connection
opening, the distance between one end portion located on one side in a circumferential direction of the
inflow chamber and the other end portion located on the other side in the circumferential direction of

the inflow chamber is smaller than the diameter of the inflow chamber.
[0017] Accordingly, the air can be exhausted from the inflow chamber to the outside, with a compact
configuration.
[0018] In the air spinning device, a section of the inflow chamber in which the connection opening
is not formed, preferably has a portion with diameter of 25 mm or more and 36 mm or less.
[0019] Accordingly, the size of the inflow chamber can be defined within an appropriate range.
[0020] In the air spinning device, the diameter of the inflow chamber preferably increases as the
distance from the fiber guide increases.
[0021] Accordingly, a compressed air injected from the nozzle of the nozzle block can be smoothly
exhausted.
[0022] The air spinning device is preferably configured as follows. That is, a maximum value of
the diameter of the inflow chamber is 25 mm or more and 36 mm or less. The difference between
the maximum value and a minimum value of the diameter of the inflow chamber is 5 mm or less.
[0023] Accordingly, a configuration in which the shape of the inflow chamber does not sharply
change can be achieved. Therefore, the air flow in the inflow chamber can be made smooth.
[0024] In the air spinning device, the volume of the inflow chamber is preferably 3000 mm3 or more
and 8000 mm3 or less.
[0025] Accordingly, a space of the inflow chamber suitable for spinning can be formed.
[0026] The air spinning device preferably further includes a hollow guide shaft which guides a yarn
to the outside.
[0027] Accordingly, the yarn spun by the swirling airflow current can be easily guided to the outside
of the air spinning device.
[0028] In the air spinning device, the hollow guide shaft that is inserted into the inflow chamber
preferably has, on such inserted portion, an inclined portion inclining at an angle of 37 degrees or more
and 70 degrees or less, with respect to the axial direction of the inflow chamber.

[0029] Accordingly, in a state in which the hollow guide shaft is inserted, it can be ensured that a
space through which the air flows in the inflow chamber has a certain size.
[0030] The air spinning device is preferably configured as follows. That is, the nozzle block has a
swirling airflow current generating chamber which generates the swirling airflow current. The
swirling airflow current generating chamber is formed in a tapered shape whose diameter increases as
the distance from the fiber guide increases. An outer circumferential surface of an inserted portion
of the hollow guide shaft that is inserted into the swirling airflow current generating chamber, is
parallel to or substantially parallel to an inner wall surface of the swirling airflow current generating
chamber. "Substantially parallel" means that the absolute value of an angle difference is 5° or smaller.
[0031] Accordingly, a swirling space of fibers for forming a yarn can be appropriately formed such
that the swirling airflow current smoothly flows in the swirling space.
[0032] The air spinning device preferably includes a pressure sensor for detecting the pressure in the
inflow chamber.
[0033] Accordingly, conventional problems are solved, the problems being failure in appropriate
detection of the pressure in the inflow chamber due to an influence of exhaust, or delay in detection of
abnormalities in the inflow chamber caused by time consumption from a start of accumulation of
foreign matter in the inflow chamber to an occurrence of a pressure change. Accordingly, the
pressure in the inflow chamber can be appropriately detected.
[0034] The diameter of the inflow chamber is preferably the diameter of a circle of a cross section
obtained by cutting the inflow chamber
[0035] According to a second aspect of the present invention, an air spinning machine with the
following configuration is provided. That is, the air spinning machine includes the air spinning
device and a draft device. The draft device forms a fiber bundle by drafting a sliver. A nozzle
distance, which is a distance from a most-downstream position in the draft device where the fiber
bundle is fed to an upstream end surface of a hollow guide shaft included in the air spinning device, is

larger than 1.5 times and smaller than 2.0 times the diameter of the inflow chamber.
[0036] Accordingly, the fiber bundle that is appropriately stretched can be introduced into the air
spinning device to be spun.
[0037] The air spinning machine further preferably includes a tension sensor for detecting tension of
a yarn formed by the air spinning device.
[0038] Accordingly, even in a case in which it is difficult to detect spinning abnormalities with the
pressure sensor, the tension sensor can obtain information on the tension of the yarn, and the spinning
abnormalities can be appropriately detected.
[0039] According to a third aspect of the present invention, an air spinning method with the following
configuration is provided. That is, in the air spinning method, the shape of the inflow chamber is
changed depending on a type of fiber bundle to be spun.
[0040] Accordingly, a size of the inflow chamber through which the swirling airflow current flows
is set to a size suitable for the type of fiber bundle. Therefore, foreign matter such as the fiber waste
contained in the fiber bundle can be easily discharged. This can improve the quality of the spun yarn.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] [Fig. 1] A front view showing an overall configuration of an air spinning machine including an air spinning device according to one embodiment of the present invention.
[Fig. 2] A side view showing a spinning unit and a yarn joining cart.
[Fig. 3] A partial cross-sectional view showing a configuration of the air spinning device.
[Fig. 4] An exploded perspective view showing a configuration of a spinning block.
[Fig. 5] A perspective view showing a configuration of the spinning block and a hollow guide shaft.
EMBODIMENT FOR CARRYING OUT THE INVENTION

[0042] Next, an air spinning machine 1 including an air spinning device 4 according to one
embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2.
[0043] The air spinning machine 1 shown in Fig. 1 includes a blower box 11, a motor box 12, a
plurality of spinning units 2, and a yarn joining cart 8. The plurality of spinning units 2 is arranged
side by side in a predetermined direction.
[0044] A blower 13 which functions as a negative pressure source, for example, is arranged inside
the blower box 11.
[0045] A driving source (not shown), a central control device 14, a display 15, and an operation unit
16 are arranged in or on the motor box 12. The driving source arranged in the motor box 12 includes
a motor commonly used in the plurality of spinning units 2.
[0046] The central control device 14 intensively manages and controls each component in the air
spinning machine 1. As shown in Fig. 2, the central control device 14 is connected to a unit control
section 20 provided in each of the spinning units 2 via a signal line (not shown). In this embodiment,
although the unit control section 20 is provided for each of the spinning units 2, the predetermined
number (for example, two or four) of spinning units 2 may share one unit control section 20.
[0047] A display 15 can display settings for each of the spinning units 2, information on a state of
each of the spinning units 2, and the like. When the display 15 is a touch panel display, the display
15 and the operation unit 16 may be assembled integrally with each other.
[0048] Each of the spinning units 2 mainly includes a draft device 3, an air spinning device 4, a yarn
accumulation device 5, and a winding device 6, which are arranged in order from upstream to
downstream. The terms "upstream" and "downstream" refer to upstream and downstream, in a
traveling direction of a sliver S, a fiber bundle F, and a spun yarn Y, at a time of winding the spun yarn
(yarn) Y.
[0049] The draft device 3 is provided near an upper end of a frame 10 in the air spinning machine 1.
As shown in Fig. 2, the draft device 3 has four pairs of draft rollers, which are a pair of back rollers

31, a pair of third rollers 32, a pair of middle rollers 33, and a pair of front rollers 34, in order from
upstream to downstream. An apron belt 35 is provided with respect to each roller in the pair of middle
rollers 33.
[0050] The draft device 3 transports the sliver S that is supplied from a sliver case (not shown) while
sandwiching the sliver S between the rollers in each pair of the draft rollers. Thereby, the sliver S is
stretched (drafted) to a predetermined fiber amount (or thickness) and then the fiber bundle F is formed.
The fiber bundle F formed by the draft device 3 is supplied to the air spinning device 4.
[0051] The air spinning device 4 applies swirling airflow current to the fiber bundle F that is formed
by the draft device 3, to twist the fiber bundle F, thereby forming the spun yarn Y. The air spinning
device 4 will be specifically described later.
[0052] The spun yarn Y that is formed in the air spinning device 4 is supplied to the yarn
accumulation device 5. As shown in Fig. 2, the yarn accumulation device 5 has a yarn accumulation
roller 51, and a motor 52.
[0053] The yarn accumulation roller 51 is rotationally driven by the motor 52. The yarn
accumulation roller 51 temporarily accumulates the spun yarn Y by winding the spun yarn Y on an
outer peripheral surface thereof. The yarn accumulating roller 51 pulls the spun yarn Y from the air
spinning device 4 and transports the spun yarn Y to the downstream side at a predetermined speed by
being rotated at a predetermined rotational speed with the spun yarn Y wound on the outer peripheral
surface of the yarn accumulating roller 51.
[0054] As such, since the yarn accumulating device 5 can temporarily accumulate the spun yarn Y
on the outer peripheral surface of the yarn accumulating roller 51, the yarn accumulating device 5
functions as a kind of buffer of the spun yarn Y. The buffering function of the yarn accumulating
device 5 avoids troubles (for example, slackening and the like of the spun yarn Y) caused by a
mismatch in a spinning speed of the air spinning device 4 and a winding speed (a traveling speed of
the spun yarn Y being wound into a package 60 which will be described later) due to some reason.

[0055] A yarn monitoring device 50 and a tension sensor 53 are provided between the air spinning device 4 and the yarn accumulation device 5. The spun yarn Y that is formed in the air spinning device 4 passes through the yarn monitoring device 50 and the tension sensor 53 before being accumulated by the yarn accumulation device 5.
[0056] The yam monitoring device 50 monitors the quality of the traveling spun yarn Y by using a light sensor, and detects a yarn defect contained in the spun yam Y. The yam defect includes abnormalities in the thickness of the spun yam Y, and foreign matters contained in the spun yarn Y, etc. The yarn monitoring device 50 transmits a yarn defect detection signal to the unit control section 20 when the yarn defect of the spun yam Y is detected. The yarn monitoring device 50 may monitor the quality of the spun yarn Y by using a capacitance sensor, for example, instead of the light sensor. Instead of or in addition to the above-described sensors, the yarn monitoring device 50 may measure the tension of the spun yarn Y as the quality of the spun yarn Y.
[0057] The tension sensor 53 measures the tension of the spun yarn Y which travels between the air spinning device 4 and the yarn accumulation device 5. The tension sensor 53 transmits a measured tension value to the unit control section 20.
[0058] Upon receipt of the yarn defect detection signal from the yarn monitoring device 50 or upon receipt of the tension value with abnormalities, from the tension sensor 53, the unit control section 20 causes the spun yarn Y to be cut by stopping the drive of the air spinning device 4 and/or the draft device 3. That is, the air spinning device 4 functions as a cutting section for cutting the spun yam Y when the yarn monitoring device 50 detects the yarn defect. Each of the spinning units 2 may have a cutter for cutting the spun yam Y.
[0059] The winding device 6 includes a cradle arm 61, a winding drum 62, and a traverse guide 63. The cradle arm 61 is swingably supported around a supporting shaft 64. The cradle arm 61 can rotatably support a bobbin 65 (that is, the package 60) for winding the spun yarn Y. The winding drum 62 is rotated in contact with the outer peripheral surface of the bobbin 65 or the package 60, and

thereby the package 60 is rotationally driven in a winding direction. The winding device 6 drives the winding drum 62 by an electric motor (not shown) while causing the traverse guide 63 to reciprocatingly move by using a driving member (not shown). Accordingly, the spun yarn Y is wound into the package 60 while being traversed.
[0060] As shown in Fig. 1, a rail 81 is provided on the frame 10 in the air spinning machine 1 along the direction in which the plurality of spinning units 2 is arranged side by side. The yarn j oining cart 8 is configured to travel on the rail 81. Accordingly, the yarn joining cart 8 can be moved with respect to the plurality of spinning units 2. The yarn joining cart 8 travels to each spinning unit 2 in which a yarn breakage or a yarn cutting has occurred, and then performs a yarn joining work with respect to such spinning unit 2.
[0061 ] As shown in Fig. 1, the yarn j oining cart 8 includes a traveling wheel 82, a yarn j oining device 83, a suction pipe 84 and a suction mouth 85. The yarn joining cart 8 further includes a cart control section 80 as shown in Fig. 2.
[0062] The suction pipe 84 can catch the spun yarn Y formed by the air spinning device 4 during yarn discharge spinning. Specifically, the suction pipe 84 generates a suction air stream at its tip, which can suck and catch the spun yarn Y fed from the air spinning device 4. The suction mouth 85 can catch the spun yarn Y wound around the package 60 of the winding device 6. Specifically, the suction mouth 85 generates the suction air stream at its tip, which can suck and catch the spun yarn Y from the package 60 that is supported by the winding device 6. The suction pipe 84 and the suction mouth 85 are swung with the caught spun yarn Y, and thereby guide the spun yarn Y to a position where the spun yarn Y can be introduced to the yarn joining device 83.
[0063] The yarn joining device 83 joins the spun yarn Y from the air spinning deice 4 that is guided by the suction pipe 84 and the spun yarn Y from the package 60 that is guided by the suction mouth 85. In this embodiment, the yarn joining device 83 is a splicer device in which the yarn ends are twisted by using the swirling airflow current. The yarn joining device 83 is not limited to the above-

described splicer device. For example, a mechanical knotter etc. may be adopted.
[0064] The cart control section 80 (see Fig. 2) is configured as a known computer having a CPU, a
ROM, and a RAM, etc. (not shown). The cart control section 80 controls the operations of each
component included in the yarn joining cart 8, and thereby controls the yarn joining work performed
by the yarn joining cart 8.
[0065] Next, a configuration of the air spinning device 4 will be specifically described with reference
to Fig. 3, etc.
[0066] As shown in Fig. 3, the air spinning device 4 mainly includes a spinning block 41 and a hollow
guide shaft 42.
[0067] The fiber bundle F that is supplied from the draft device 3 is guided into the spinning block
41, and then the swirling airflow current is applied to the fiber bundle F. The unit control section 20
controls to generate and stop the swirling airflow current. The spinning block 41 mainly includes, as
shown in Fig. 3 and Fig. 4, a fiber guide 41a, a nozzle block 41b, a nozzle head (inflow chamber
forming block) 41c, and a nozzle cap 4Id.
[0068] The fiber guide 41a is a member for guiding the drafted fiber bundle F to a swirling airflow
current generating chamber 40 which will be described later. As shown in Fig. 4, the fiber guide 41a
has a guide hole 41e which penetrates the fiber guide 41a in a fiber bundle traveling direction (in the
vertical direction in Fig. 4). The fiber bundle F which passes through the guide hole 41 e, is introduced
into the swirling airflow current generating chamber 40.
[0069] The swirling airflow current generating chamber 40 is formed inside the nozzle block 41b.
As shown in Fig. 3, the swirling airflow current generating chamber 40 has a tapered shape whose
diameter increases from upstream to downstream. In the swirling airflow current generating chamber
40, by injecting the compressed air (air) from a nozzle (not shown), the swirling airflow current which
acts on the fiber bundle F is generated. With such action of the swirling airflow current, each fiber
end of the plurality of fibers forming the fiber bundle F is inverted and swirled.

[0070] The nozzle block 41b has a plurality of nozzles (not shown) through which the air injected to the swirling airflow current generating chamber 40 passes. Each of the nozzles is, for example, an elongated hole formed in the nozzle block 41b (a wall defining the swirling airflow current generating chamber 40). Each nozzle is provided such that its longitudinal direction is slightly inclined toward a downstream side in a yarn feeding direction. The plurality of nozzles is arranged at equal angular interval around the swirling airflow current generating chamber 40. The compressed air that is supplied from a compressed air source (not shown) is injected into the swirling airflow current generating chamber 40 via each nozzle. The air that is injected from each nozzle flows toward the downstream side while swirling around the hollow guide shaft 42 (which will be described later) that is inserted into the swirling airflow current generating chamber 40. As such, the swirling airflow current flowing in a counterclockwise direction as viewed in the direction from upstream to downstream, is generated in the swirling airflow current generating chamber 40. The swirling airflow current flows toward the downstream side (an inflow chamber 7) in a spiral manner. [0071] The nozzle head 41c and the nozzle cap 41d hold the fiber guide 41a and the nozzle block 41b. The nozzle head 41c and the nozzle cap 41d function as a casing which accommodates a part of the fiber guide 41a and the nozzle block 41b.
[0072] The nozzle head 41c is formed in a block shape with a certain thickness. As shown in Fig. 4, when viewed in the thickness direction, the nozzle head 41c has a shape of a rectangle to which a semicircle is connected to one side of the rectangle, the semicircle having diameter equal to the length of such one side. In the following description, the direction in which the above-described rectangle and the semicircle are arranged may be referred to as a longitudinal direction of the nozzle head 41c. The inflow chamber 7 and an air exhaust passage (exhaust passage) 70 are formed in the nozzle head 41c.
[0073] The inflow chamber 7 is formed in a substantially columnar shape on one side in the longitudinal direction of the nozzle head 41c. A central axis of the inflow chamber 7 coincides with

the center of the semicircle of the nozzle head 41c. The inflow chamber 7 is connected to the swirling airflow current generating chamber 40. Most of the inflow chamber 7 is located at a position farther than the swirling airflow current generating chamber 40 when viewed from the fiber guide 41a. [0074] The hollow guide shaft 42 which will be specifically described later, is inserted in the center of the inflow chamber 7. A ring-shaped gap is formed between an inner wall of the inflow chamber 7 and the hollow guide shaft 42. A ring-shaped portion in an internal space of the inflow chamber 7, the ring-shaped portion where the hollow guide shaft 42 is not placed, effectively functions as an air passage.
[0075] When the inflow chamber 7 is cut perpendicular to a traveling direction of the spun yarn Y, its cross section has a circular shape. The traveling direction of the spun yarn Y can be rephrased as the axial direction of the inflow chamber 7. In this embodiment, the outer diameter of the inflow chamber 7 gradually increases as the distance from the fiber guide 41a increases. Therefore, as a position where the inflow chamber 7 is cut approaches the downstream side, the diameter of the circle of the above-described cross section (corresponding to the diameter of the outer circumference of the inflow chamber 7) gradually increases.
[0076] Fig. 5 shows a maximum diameter Dl that is the diameter of a portion with the largest outer circumference (in other words, a portion farthest from the swirling airflow current generating chamber 40) of the inflow chamber 7 and a minimum diameter D2 that is the diameter of a portion with the smallest outer circumference of the inflow chamber 7, as indicated by an outline arrow. In this embodiment, both the maximum diameter Dl and the minimum diameter D2 are 28 mm or more and less than 34 mm. However, the present invention is not limited to such range. The maximum diameter Dl can be set within the range of 25 mm or more and 36 mm or less, depending on the type of fiber bundle F to be spun.
[0077] As described above, in this embodiment, the inflow chamber 7 has various diameters. In the following, an average diameter of the inflow chamber 7 may be simply referred to as a diameter D of

the inflow chamber 7. The diameter D is shown in Fig. 3. The diameter D of the inflow chamber 7 can be, for example, an arithmetic mean of the maximum diameter Dl and the minimum diameter D2. The diameter D of the inflow chamber 7 is larger than the minimum diameter D2 and smaller than the maximum diameter Dl.
[0078] A portion that is connected to the air exhaust passage 70 via a connection opening 71, is formed on the outer circumference of the inflow chamber 7, which will be specifically described later. When the inflow chamber 7 is cut so as to include the above-described connection portion, its cross section is not a circular shape. However, such cross section has an arc-shaped portion. It is sufficient to consider the diameter of the arc. Alternatively, when the inflow chamber 7 is cut at its portion where the connection opening 71 is not formed in the same manner as above, it is sufficient that the inflow chamber 7 has a portion whose diameter of its circular cross section is within the range of 25 mm or more and 36 mm or less.
[0079] The axial direction of the inflow chamber 7 is a direction connecting front and back when viewed in the direction where the fiber bundle F or the spun yarn Y passes through the air spinning device 4. Considering this direction, in the following, the length of the inflow chamber 7 in the axial direction is referred to as a depth. The depth is indicated by a reference numeral LI, in Fig. 3 and Fig. 5. The outer circumference at one end of the inflow chamber 7 in the axial direction can be formed in an arc fillet shape as shown in Fig. 3. In this case, the depth LI is a depth of a portion excluding the fillet portion. Instead of the arc fillet shape, a chamfered shape can be also adopted. In this case, the depth LI is a depth of a portion excluding the chamfered portion. In this embodiment, the depth LI is 38% or more and 75% or less of the diameter D of the inflow chamber 7. [0080] The size of the depth LI of the inflow chamber 7 is set in accordance with the diameter D of the inflow chamber 7 and an inclination angle of a tapered surface 43 of a shaft holder 42b which will be described later. In this embodiment, the depth LI of the inflow chamber 7 is 14 mm or more and 25 mm or less. This can maintain a sufficient volume of the inflow chamber 7.

[0081] In the inflow chamber 7 of this embodiment, a difference between the diameter of a portion with the largest outer circumference (the above-described maximum diameter Dl) and the minimum diameter D2, which is the diameter of a portion with the smallest outer circumference, is 5mm or smaller. In this embodiment, the difference between the maximum diameter Dl and the minimum diameter D2 is 3mm.
[0082] The inflow chamber 7 that is formed as described above, has the volume of 3000 mm3 or more and 8000 mm3 or less. Here, the volume of the inflow chamber 7 is a volume, in a substantially cylindrical internal space in the inflow chamber 7, excluding a portion into which the swirling airflow current does not flow (specifically, a portion in which the hollow guide shaft 42 etc. is inserted). In the nozzle head 41c, although the inflow chamber 7 is connected to the air exhaust passage 70, the volume described herein does not include the volume of the air exhaust passage 70. [0083] The inflow chamber 7 is formed such that its side facing the hollow guide shaft 42, which will be described later, is opened. In other words, in the inflow chamber 7, one side opposite to the side where the nozzle block 41b is inserted is opened. Through this opened side, the hollow guide shaft 42 can be inserted into the inflow chamber 7.
[0084] The inflow chamber 7 has the connection opening 71 which opens toward the air exhaust passage 70. The inflow chamber 7 is connected to the air exhaust passage 70 through the connection opening 71. The air inside the inflow chamber 7 is exhausted to the outside through the air exhaust passage 70.
[0085] The air exhaust passage 70 is straight and elongated. The longitudinal direction of the air exhaust passage 70 is parallel to the longitudinal direction of the nozzle head 41c and perpendicular to the traveling direction of the spun yarn Y (the axial center of the hollow guide shaft 42). The cross section that is cut perpendicular to the longitudinal direction of the air exhaust passage 70 has a rectangular shape. The air exhaust passage 70 is formed so as to be opened to a side opposite to the side where the inflow chamber 7 is formed, in the longitudinal direction of the nozzle head 41c. That

is, the air exhaust passage 70 connects the inflow chamber 7 and an outside of the air spinning device 4. Specifically, the outside of the air spinning device 4 is a negative pressure source including the blower 13 etc. which sucks with a weak force. The air exhaust passage 70 is connected to, for example, the blower 13 via a duct (not shown), etc. arranged along an arrangement direction of the spinning units 2.
[0086] The inflow chamber 7 is located on the downstream side of the swirling airflow current generating chamber 40, in a flow of the swirling airflow current. The inflow chamber 7 has a relatively larger space than the swirling airflow current generating chamber 40. Therefore, the pressure in the inflow chamber 7 is lower than the pressure in the swirling airflow current generating chamber 40. The degree in which the pressure in the inflow chamber 7 is lower than that in the swirling airflow current generating chamber 40, is greatly affected by the size of the inflow chamber 7.
[0087] In this regard, in this embodiment, the pressure in the inflow chamber 7 can be appropriately maintained by forming the inflow chamber 7 with a size depending on the type of the fiber bundle F. It is conceivable that, for example, plural spinning blocks 41 with the maximum diameter Dl, the minimum diameter D2, and the depth LI, etc., respectively having various sizes, are prepared in advance and then one of the spinning blocks 41 is replaced with the other spinning block 41 depending on the fiber bundle F to be used. Accordingly, an air flow in the swirling airflow current generating chamber 40 can flow into the inflow chamber 7 at an appropriate speed. Then, the fiber waste which has dropped out of the fiber bundle F is carried by the air flow and easily introduced into the inflow chamber 7.
[0088] The fiber waste in the inflow chamber 7 is easily discharged from the air spinning device 4 through the air exhaust passage 70 without remaining in the inflow chamber 7 by a suction force of the negative pressure source. As a result, in the swirling airflow current generating chamber 40, the fiber waste is smoothly discharged without remaining in the fiber bundle F for forming the spun yarn

Y. Therefore, the spun yarn Y with high quality can be formed. As such, since the fiber waste and the like are less likely to remain in the inflow chamber 7, foreign matters such as the fiber waste are less likely to come into contact with fibers rotating while being inverted in the swirling airflow current generating chamber 40. Therefore, the tension of the fiber bundle F can be stabilized. [0089] The connection opening 71 is formed in a substantially rectangular shape (a rectangular shape with rounded corners) as shown in Fig. 5. In the connection opening 71, a distance L2 between an end portion located on one side in the circumferential direction of the inflow chamber 7 and an end portion located on the other side in the circumferential direction of the inflow chamber 7 is smaller than the maximum diameter Dl. Accordingly, with a compact configuration, the air flow can be smoothly exhausted from the inflow chamber 7.
[0090] An insertion hole 41f for receiving a part of the nozzle block 41b is formed on one of surfaces of the nozzle head 41c, the one of the surfaces being a surface which faces the nozzle cap 4Id. A part of the nozzle block 41b is inserted into the inflow chamber 7 through the insertion hole 41f. [0091] When assembling the spinning block 41, a part of the nozzle block 41b, as shown in Fig. 4, etc., is inserted into the inflow chamber 7 through the above-described insertion hole 41f. Accordingly, the swirling airflow current generating chamber 40 formed in the nozzle block 41b and the inflow chamber 7 formed in the nozzle head 41c are connected to each other. Therefore, the swirling airflow current formed in the swirling airflow current generating chamber 40 can flow into the inflow chamber 7.
[0092] A pressure sensor 9 for detecting the pressure in the inflow chamber 7 is provided in each spinning unit 2 of this embodiment, as shown in Fig. 3. The pressure sensor 9 detects the pressure in the inflow chamber 7 via, for example, a tube (not shown) that is inserted in a pressure detection hole penetrating through a wall of the inflow chamber 7. The pressure sensor 9 is electrically connected to the unit control section 20. The pressure sensor 9 transmits a signal indicating the detected pressure to the unit control section 20. The unit control section 20 determines whether or not abnormalities

such as clogging in the inflow chamber 7 have occurred, based on the pressure obtained from the pressure sensor 9.
[0093] In the air spinning device 4 of this embodiment, as described above, the maximum diameter Dl of the inflow chamber 7 is 25 mm or more, preferably 28 mm or more. The inflow chamber 7 has a relatively large size. Therefore, the pressure detection hole for detecting the pressure in the inflow chamber 7 can be provided at a position away from the connection opening 71. As a result, detection of the pressure is less affected by exhaust, thereby a change in the pressure in the inflow chamber 7 can be accurately detected.
[0094] However, in this embodiment, the above-described maximum diameter Dl is 36 mm or less, preferably less than 34 mm. The inflow chamber 7 is not too large. Therefore, even when the foreign matters such as the fiber waste are accumulated in the inflow chamber 7, the pressure in the inflow chamber 7 is likely to be changed. Before a large amount of the foreign matters such as the fiber waste are accumulated in the inflow chamber 7, the foreign matters such as the fiber waste can be discharged by performing an appropriate operation (for example, an automatic cleaning operation) based on a pressure detection. This can avoid the foreign matters such as the fiber waste from adhering to the spun yarn Y.
[0095] The nozzle cap 41d is arranged on the nozzle head 41c. The nozzle cap 41d is removably mounted to the nozzle head 41c via a bolt, for example. As shown in Fig. 4, the nozzle cap 41d is formed in a plate-like shape whose cross section cut perpendicular to the traveling direction of the fiber bundle F is circular. A through hole through which a part of the fiber guide 41a passes, is formed in the center of the nozzle cap 4 Id.
[0096] When assembling the spinning block 41, as shown in Fig. 3 or Fig. 5, the fiber guide 41a is passed through the through hole, from the downstream side of the nozzle cap 41d (a downstream side in the yarn traveling direction during spinning) and then passed through the nozzle cap 4Id. Then, a head (an upstream end portion) of the fiber guide 41a is exposed upward (the upstream side in the yarn

traveling direction, the draft device 3 side) from the nozzle cap 4Id.
[0097] The nozzle cap 41d is mounted on the nozzle head 41c, thereby the fiber guide 41a and the nozzle block 41b are sandwiched between the nozzle head 41c and the nozzle cap 41d and their positions are fixed. In this way, the spinning block 41 is assembled.
[0098] The hollow guide shaft 42 is provided on the downstream side of the spinning block 41. A position of the hollow guide shaft 42 is switchable between a contact position in contact with the spinning block 41 and a separation position located away from the spinning block 41. Switching of the position of the hollow guide shaft 42 is performed by a movement mechanism (not shown). When the hollow guide shaft 42 is located in the contact position, the hollow guide shaft 42 closes the opened side in the inflow chamber 7 so as to form the inflow chamber 7 in a closed manner. When the hollow guide shaft 42 is located in the separation position, the inflow chamber 7 is opened to the outside. In a state where the inflow chamber 7 is closed, a suction device (not shown, for example, the above-described negative pressure source) can be used to remove the fiber waste remaining in the inflow chamber 7. In a state where the inflow chamber 7 is opened, the fiber waste remaining in the swirling airflow current generating chamber 40 or on a tip of the hollow guide shaft 42 can be removed by injecting the air from the nozzle of the nozzle block 41b, for example.
[0099] The hollow guide shaft 42 is fixed to a hollow guide shaft holding part (not shown). The hollow guide shaft holding part and the hollow guide shaft 42 form a guide shaft block. The hollow guide shaft 42 includes a shaft body 42a and a shaft holder 42b.
[0100] A cylindrical yarn passage is formed inside the shaft body 42a. The yarn passage leads the fiber bundle F, which has been spun in the swirling airflow current generating chamber 40, to the outside as the spun yarn Y. The swirling airflow current which flows from upstream to downstream may be generated in the yarn passage, by injecting the air from the nozzle (not shown). When viewed in the direction from upstream to downstream, the direction of the swirling airflow current generated in the yarn passage is opposite to the direction of the swirling airflow current in the swirling airflow

current generating chamber 40. In Fig. 3, a tip (an inlet of the yarn passage) of the shaft body 42a which forms a part of the swirling airflow current generating chamber 40 and the entire yarn passage are integrally formed therewith. The nozzle (not shown) may be formed as a tubular member separated from the shaft body 42a. The tubular member may be placed inside the shaft body 42a. The yarn passage may be formed by a plurality of members.
[0101] An upstream portion of the shaft body 42a is formed in a conical shape. The conical-shaped upstream portion of the shaft body 42a is formed slightly smaller than the taper-shaped space of the swirling airflow current generating chamber 40. The upstream portion of the shaft body 42a is inserted into the swirling airflow current generating chamber 40.
[0102] As shown in Fig. 3, the outer circumferential surface of the upstream portion of the shaft body 42a, which is inserted into the swirling airflow current generating chamber 40, is formed substantially parallel to an inner wall surface forming the swirling airflow current generating chamber 40 in the nozzle block 41b. That is, the distance between an outer wall surface of the upstream portion of the shaft body 42a, which is inserted into the swirling airflow current generating chamber 40, and the inner wall surface of the swirling airflow current generating chamber 40 facing the outer wall surface, is almost constant. Accordingly, easiness of the flow of the air of the swirling airflow current through a flow passage, can be avoided from sharply being changed. Therefore, in the swirling airflow current generating chamber 40, it is possible to avoid a sharp change in a speed of the air flow and to perform stable spinning. However, the shape of the upstream portion of the shaft body 42a and/or the shape of the inner wall surface of the swirling airflow current generating chamber 40 may be different from the shapes described above. The above-described distance may not be constant. For example, the distance on the upstream side may be larger or smaller than the distance on the downstream side.
[0103] In a state where the spinning block 41 and the hollow guide shaft 42 are in contact with each other, the upstream portion of the shaft body 42a passes through the inflow chamber 7 and protrudes

into the swirling airflow current generating chamber 40. Accordingly, a tapered tubular space is formed between the shaft body 42a and the swirling airflow current generating chamber 40. In this space, fibers contained in the fiber bundle F are swirled by the action of the swirling airflow current. [0104] The shaft holder 42b is used for holding the shaft body 42a. The shaft holder 42b with a tapered shape has its outer diameter which gradually increases from upstream to downstream. A holding hole is formed through the shaft holder 42b. An orientation of the holding hole is parallel to the traveling direction of the spun yarn Y (the axial direction of the yarn passage). The shaft holder 42b holds the shaft body 42a in a state in which a downstream portion of the shaft body 42a is inserted into the holding hole.
[0105] An upstream portion of the shaft holder 42b is formed in a conical shape whose diameter increases as the distance from the nozzle block 41b increases. In the following description, a tapered outer circumferential surface that is formed on the upstream portion of the shaft holder 42b may be referred to as the tapered surface (inclined surface) 43. An inclination angle (inner angle) 9 formed by the tapered surface 43 with respect to an axis of the hollow guide shaft 42 is 37 degrees or more and 70 degrees or less. Accordingly, a sufficient space for flowing and exhausting the air can be formed between the hollow guide shaft 42 and the wall of the inflow chamber 7. Therefore, the fiber waste can be smoothly discharged by the air flow.
[0106] As shown in Fig. 3, the air spinning device 4 of this embodiment is provided downstream of the draft device 3. Specifically, the air spinning device 4 is provided downstream of the draft device 3 such that a nozzle distance L3, which is the distance between a position (a nip point by the pair of front rollers 34) where the fiber bundle F is discharged from the pair of front rollers 34 in the draft device 3 and an upstream end surface (tip) of the hollow guide shaft 42 in the air spinning device 4, is larger than 1.5 times and smaller than 2.0 times the diameter D of the inflow chamber 7. Accordingly, the fiber bundle F is appropriately stretched and introduced into the air spinning device 4 in a stable state, resulting in the spun yarn Y with favorable quality.

[0107] As described above, the air spinning device 4 of this embodiment forms the spun yarn Y by
applying twists to the fiber bundle F by using the swirling airflow current. The air spinning device 4
includes the fiber guide 41a, the nozzle block 41b, and the nozzle head 41c. The fiber guide 41a
guides the fiber bundle F. The nozzle block 41b has the nozzle through which the compressed air
passes, the compressed air for generating the swirling airflow current to be acted on the fiber bundle F
that has been guided by the fiber guide 41a. The nozzle head 41c has the inflow chamber 7 in which
the swirling airflow current flows. The inflow chamber 7 has a portion whose diameter is 25 mm or
more and 36 mm or less.
[0108] Accordingly, the inflow chamber 7 capable of easily collecting the fiber waste can be formed.
As a result, each fiber contained in the fiber bundle F can be smoothly swirled by the action of the
swirling airflow current, and the spun yarn Y with high quality can be formed.
[0109] In the air spinning device 4 of this embodiment, the inflow chamber 7 has a portion whose
diameter is 28 mm or more and less than 34 mm.
[0110] Accordingly, the fiber waste can be further easily collected.
[0111] In the air spinning device 4 of this embodiment, the length (depth LI) of the inflow chamber
7 in its axial direction is 38% or more and 75% or less of the diameter D of the inflow chamber 7.
[0112] Accordingly, the inflow chamber 7 suitable for a shape of the hollow guide shaft 42 can be
formed.
[0113] In the air spinning device 4 of this embodiment, the length (the depth LI) of the inflow
chamber 7 in its axial direction is 14 mm or more and 25 mm or less.
[0114] Accordingly, the inflow chamber 7 with an appropriate size can be formed.
[0115] In the air spinning device 4 of this embodiment, the nozzle head 41c has the connection
opening 71. The inflow chamber 7 is connected to the air exhaust passage 70, which exhausts the
swirling airflow current, via the connection opening 71.
[0116] Accordingly, the air can be exhausted from the inflow chamber 7. The fiber waste collected

in the inflow chamber 7 can be easily discharged.
[0117] In the air spinning device 4 of this embodiment, in the connection opening 71, the distance
L2 between one end portion located on one side in the circumferential direction of the inflow chamber
7 and the other end portion located on the other side in the circumferential direction of the inflow
chamber 7 is smaller than the diameter D of the inflow chamber 7.
[0118] Accordingly, the air can be exhausted from the inflow chamber 7 to the outside, with a
compact configuration.
[0119] In the air spinning device 4 of this embodiment, a section of the inflow chamber 7 in which
the connection opening 71 is not formed, has a portion with diameter of 25 mm or more and 36 mm or
less.
[0120] Accordingly, the size of the inflow chamber 7 can be defined within an appropriate range.
[0121] In the air spinning device 4 of this embodiment, the diameter of the inflow chamber 7
increases as the distance from the fiber guide 41a increases.
[0122] Accordingly, the compressed air injected from the nozzle of the nozzle block 41b can be
smoothly exhausted.
[0123] In the air spinning device 4 of this embodiment, the maximum diameter Dl of the inflow
chamber 7 is 25 mm or more and 36 mm or less. The difference between the maximum diameter Dl
and the minimum diameter D2 of the inflow chamber 7 is 5 mm or less.
[0124] Accordingly, a configuration in which the shape of the inflow chamber 7 does not sharply
change can be achieved. Therefore, the air flow in the inflow chamber 7 can be made smooth.
[0125] In the air spinning device 4 of this embodiment, the volume of the inflow chamber 7 is 3000
mm3 or more and 8000 mm3 or less.
[0126] Accordingly, a space of the inflow chamber 7 suitable for spinning can be formed.
[0127] The air spinning device 4 of this embodiment further includes the hollow guide shaft 42 which
guides the spun yarn Y to the outside.

[0128] Accordingly, the spun yarn Y spun by the swirling airflow current can be easily guided to the
outside of the air spinning device 4.
[0129] In the air spinning device 4 of this embodiment, the hollow guide shaft 42 that is inserted into
the inflow chamber 7 has, on such inserted portion, the tapered surface 43 inclined at an angle of 37
degrees or more and 70 degrees or less, with respect to the axial direction of the inflow chamber 7.
[0130] Accordingly, in a state in which the hollow guide shaft 42 is inserted, it can be ensured that a
space through which the air flows in the inflow chamber 7 has a certain size.
[0131] In the air spinning device 4 of this embodiment, the nozzle block 41b has the swirling airflow
current generating chamber 40 which generates the swirling airflow current. The swirling airflow
current generating chamber 40 is formed in a tapered shape whose diameter increases as the distance
from the fiber guide 41a increases. The outer circumferential surface of an inserted portion of the
hollow guide shaft 42 that is inserted into the swirling airflow current generating chamber 40, is parallel
to or substantially parallel to the inner wall surface of the swirling airflow current generating chamber
40.
[0132] Accordingly, a swirling space of the fibers for forming the spun yarn Y can be appropriately
formed such that the swirling airflow current smoothly flows in the swirling space.
[0133] The air spinning device 4 of this embodiment includes the pressure sensor 9 for detecting the
pressure in the inflow chamber 7.
[0134] Accordingly, conventional problems are solved, the problems being failure in appropriate
detection of the pressure in the inflow chamber 7 due to an influence of exhaust, or delay in detection
of abnormalities in the inflow chamber 7 caused by time consumption from a start of accumulation of
foreign matter in the inflow chamber 7 to an occurrence of a pressure change. Accordingly, the
pressure in the inflow chamber 7 can be appropriately detected by the pressure sensor 9.
[0135] It is conceivable that the diameter of the inflow chamber 7 is the diameter of a circle of a cross
section obtained by cutting the inflow chamber 7 (on a plane perpendicular to the axial direction of the

inflow chamber 7).
[0136] As described above, the air spinning machine 1 of this embodiment includes the air spinning
device 4 and the draft device 3. The draft device 3 forms the fiber bundle F by drafting a sliver. The
nozzle distance L3, which is the distance from a position in the draft device 3 (a nip point by the pair
of front rollers 34) where the fiber bundle F is fed at the most downstream to an upstream end surface
of the hollow guide shaft 42, is larger than 1.5 times and smaller than 2.0 times the diameter D of the
inflow chamber 7.
[0137] Accordingly, the fiber bundle F that is appropriately stretched can be introduced into the air
spinning device 4 to be spun.
[0138] The air spinning machine 1 of this embodiment further includes the tension sensor 53 for
detecting tension of the spun yarn Y formed by the air spinning device 4.
[0139] Accordingly, even in a case in which it is difficult to detect spinning abnormalities with the
pressure sensor 9, the tension sensor 53 can provide information on the tension of the spun yarn Y.
Then, the spinning abnormalities can be appropriately detected.
[0140] Although a preferred embodiment of the present invention has been described above, the
above-described configuration can be modified, for example, as follows.
[0141] A pair of delivery rollers provided between the air spinning device 4 and the yarn
accumulation device 5, may pull the spun yarn Y from the air spinning device 4. In this case, at least
one of the yarn accumulation device 5, a slack tube using a suction air stream, and a mechanical
compensator, may be provided downstream of the pair of delivery rollers.
[0142] The yarn joining cart 8 may cause the spun yarn Y to be a continuous state with a knotter
device, piecing, etc. instead of the splicer device. Alternately, the yarn joining cart 8 may be omitted,
and each spinning unit 2 may have an equipment required for yarn joining.
[0143] In each spinning unit 2, each device may be arranged such that, in a height direction, the spun
yarn Y supplied from a lower side is wound on an upper side.

[0144] Although Fig. 3, etc. show a configuration in which a needle-shaped member is provided on the fiber guide 41a, the air spinning device 4 may not have the needle-shaped member. Instead of separate members, one member may constitute the fiber guide 41a and the nozzle block 41b. [0145] In the above-described embodiment, although each spinning unit 2 includes both the pressure sensor 9 and the tension sensor 53, each spinning unit 2 may include only one of the pressure sensor 9 or the tension sensor 53.
[0146] In the above-described embodiment, specific devices in the plurality of spinning units 2 are driven in the plurality of spinning units 2 at the same time by the driving source provided in the motor box 12. Each spinning unit 2 may be configured such that some or all of these specific devices are driven independently in each spinning unit 2.
DESCRIPTION OF THE REFERENCE NUMERALS
[0147] 4 air spinning device
7 inflow chamber
41a fiber guide
41b nozzle block
41c nozzle head
F fiber bundle
Y spun yarn (yarn)

WE CLAIM
1. An air spinning device (4) adapted to form a yarn (Y) by applying twists to a fiber bundle (F)
by using a swirling airflow current, the air spinning device (4) comprising:
a fiber guide (41a) which guides the fiber bundle (F);
a nozzle block (41b) having a nozzle through which a compressed air passes, the compressed air for generating the swirling airflow current acting on the fiber bundle (F) that has been guided by the fiber guide (41a); and
an inflow chamber forming block (41c) having an inflow chamber (7) in which the swirling airflow current flows, wherein
the inflow chamber (7) has a portion whose diameter is 25 mm or more and 36 mm or less.
2. The air spinning device (4) as claimed in claim 1, wherein
the inflow chamber (7) has a portion whose diameter is 28 mm or more and less than 34 mm.
3. The air spinning device (4) as claimed in claim 1 or 2, wherein
a length of the inflow chamber (7) in its axial direction is 38% or more and 75% or less of the diameter of the inflow chamber (7).
4. The air spinning device (4) as claimed in claim 3, wherein
the length of the inflow chamber (7) in its axial direction is 14 mm or more and 25 mm or less.
5. The air spinning device (4) as claimed in any one of claims 1 to 4, wherein
the inflow chamber (7) is connected to an exhaust passage (70), which exhausts the swirling

airflow current, via a connection opening (71) formed in the inflow chamber forming block (41c).
6. The air spinning device (4) as claimed in claim 5, wherein
in the connection opening (71), a distance between one end portion located on one side in a circumferential direction of the inflow chamber (7) and the other end portion located on the other side in the circumferential direction of the inflow chamber (7) is smaller than the diameter of the inflow chamber (7).
7. The air spinning device (4) as claimed in claim 5 or 6, wherein
the inflow chamber (7) has a section in which the connection opening (71) is not formed, the section has a portion with diameter of 25 mm or more and 36 mm or less.
8. The air spinning device (4) as claimed in any one of claims 1 to 7, wherein
the diameter of the inflow chamber (7) increases as the distance from the fiber guide (41a) increases.
9. The air spinning device (4) as claimed in claim 8, wherein
a maximum value of the diameter of the inflow chamber (7) is 25 mm or more and 36 mm or less, and
a difference between the maximum value and a minimum value of the diameter of the inflow chamber (7) is 5 mm or less.
10. The air spinning device (4) as claimed in any one of claims 1 to 9, wherein
a volume of the inflow chamber (7) is 3000 mm3 or more and 8000 mm3 or less.

11. The air spinning device (4) as claimed in any one of claims 1 to 10, comprising a hollow guide shaft (42) which guides a yarn (Y) to the outside.
12. The air spinning device (4) as claimed in claim 11, wherein
the hollow guide shaft (42) that is inserted into the inflow chamber (7) has, on such inserted portion, an inclined surface (43) inclining at an angle of 37 degrees or more and 70 degrees or less, with respect to the axial direction of the inflow chamber (7).
13. The air spinning device (4) as claimed in claim 11 or 12, wherein
the nozzle block (41b) has a swirling airflow current generating chamber (40) which generates the swirling airflow current,
the swirling airflow current generating chamber (40) is formed in a tapered shape whose diameter increases as the distance from the fiber guide (41a) increases,
an outer circumferential surface of an inserted portion of the hollow guide shaft (42) that is inserted into the swirling airflow current generating chamber (40) is parallel to or substantially parallel to an inner wall surface of the swirling airflow current generating chamber (40).
14. The air spinning device (4) as claimed in any one of claims 1 to 13, comprising a pressure sensor (9) for detecting a pressure in the inflow chamber (7).
15. The air spinning device (4) as claimed in any one of claims 1 to 14, wherein
the diameter of the inflow chamber (7) is the diameter of a circle of a cross section obtained by cutting the inflow chamber (7) .
16. An air spinning machine (1) comprising:

the air spinning device (4) as claimed in any one of claims 1 to 15; and a draft device (3) which forms a fiber bundle (F) by drafting a sliver, wherein a nozzle distance (L3), which is a distance from a most-downstream position in the draft device (3) where a fiber bundle (F) is fed to an upstream end surface of a hollow guide shaft (42) included in the air spinning device (4), is larger than 1.5 times and smaller than 2.0 times the diameter of the inflow chamber (7).
17. The air spinning machine as claimed in claim 16, comprising a tension sensor (53) for detecting a tension of a yarn (Y) formed by the air spinning device (4).
18. An air spinning method adapted to perform spinning by using the air spinning device (4) as claimed in any one of claims 1 to 15, wherein
a shape of the inflow chamber (7) is changed depending on a type of fiber bundle (F) to be
spun.