CN108977996B

CN108977996B - Air jet loom

Info

Publication number: CN108977996B
Application number: CN201810558101.9A
Authority: CN
Inventors: 木口祐一郎; 牧野洋一
Original assignee: Toyota Industries Corp
Current assignee: Toyota Industries Corp
Priority date: 2017-06-05
Filing date: 2018-06-01
Publication date: 2021-04-30
Anticipated expiration: 2038-06-01
Also published as: JP2018204143A; EP3412812A1; JP6879061B2; CN108977996A

Abstract

The invention provides an air jet loom which can prevent the generation of weft knots and can maintain high weft yarn conveying force. An air jet loom (100) is provided with a thread guide (7) provided with a tunnel (7a) extending in a weft insertion direction (Y), a main nozzle (10) for flying a weft yarn in the tunnel (7a) by air jet injection to perform weft insertion, the acceleration tube (1) of the main nozzle (10) has a tapered section (1a) whose inner diameter increases continuously from the upstream side toward the downstream side, and a straight section (1b) which is provided in connection with the downstream side of the tapered section (1a) and extends so as to have a constant inner diameter from the upstream side to the downstream side, the range of the length (A) of the linear portion (1b) is determined by the distance (c1) from the downstream-side tip portion (1c) of the acceleration tube (1) to the wire guide portion (7), the shortest distance (c2) from the central axis (T) of the acceleration tube (1) to the tunnel of the wire guide portion (7), the inclination angle (theta) of the inner surface of the tapered portion (1a), and the total length (L) of the acceleration tube (1).

Description

Air jet loom

Technical Field

The present invention relates to an air jet loom.

Background

A main nozzle of an air jet loom is a member for performing weft insertion by skipping a weft yarn using compressed air, and has an acceleration tube for accelerating the weft yarn and skipping the weft yarn.

Patent document 1 describes a laval nozzle-shaped tube having a tapered portion continuously expanding from a fluid inlet toward a fluid outlet on an inner surface as an acceleration tube. Here, as described in paragraph [0006] of patent document 1, there is a problem that the leading end of the weft yarn is disturbed at the start of weft insertion, and weft knots, which are defects of the fabric, are likely to occur in the fabric. In the main nozzle of the air jet loom described in patent document 1, the occurrence of weft knots is prevented by setting the length of the tube to 150mm or less.

Patent document 1: japanese laid-open patent publication No. 2004-156162

However, in the main nozzle of the air jet loom of patent document 1, since the length of the acceleration tube is limited to 150mm or less, there is a problem that the weft yarn conveying force cannot be increased.

Disclosure of Invention

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an air jet loom capable of preventing the occurrence of weft knots and maintaining a high weft yarn conveying force.

In order to solve the above problem, an air jet loom of the present invention includes: a guide wire part provided with a tunnel extending in a weft insertion direction; and a main nozzle for flying the weft yarn in the tunnel by air jet injection to perform weft insertion, wherein the acceleration pipe of the main nozzle comprises: a tapered portion having an inner diameter that continuously increases from an upstream side toward a downstream side; and a linear portion which is provided continuously with the downstream side of the tapered portion and extends so as to have a constant inner diameter from the upstream side to the downstream side, wherein a yarn speed ratio (q) of the weft yarn is a speed ratio (U1/U2) of a speed (U1) of the weft yarn at an arbitrary point to a speed (U2) of the downstream side leading end of the weft yarn, the yarn speed ratio (q) is determined from a relationship among a total length (L) of the acceleration tube, a ratio (A/L) of a length (A) of the linear portion to the total length (L) of the acceleration tube, and an inclination angle (theta) of the inner surface of the tapered portion, and the yarn speed ratio (q) is made smaller than a maximum value (qmax) of the yarn speed ratio (q) determined by the following equation from a relationship between a distance (c1) from the downstream side leading end of the acceleration tube to the guide portion and a shortest distance (c2) from the central axis of the acceleration tube to the tunnel of the guide portion, the total length (L) of the acceleration tube, the ratio (A/L) of the length (A) of the straight portion to the total length (L) of the acceleration tube, and the inclination angle (theta) of the inner surface of the tapered portion are determined,

[ formula 1] is:

qmax＝(c2/c1)+1。

the thrust force ratio (p) applied to the weft yarn by the acceleration tube of the air jet loom of the present invention may be determined from the relationship among the total length (L) of the acceleration tube, the ratio (a/L) of the length (a) of the linear portion to the total length (L) of the acceleration tube, and the inclination angle (θ) of the inner surface of the tapered portion, and the minimum value (pmin) of the thrust force ratio (p) may be determined from the pressure of the compressed air supplied to the main nozzle or a target value of the opening period of the valve that supplies the compressed air to the main nozzle, and the total length (L) of the acceleration tube, the ratio (a/L) of the length (a) of the linear portion to the total length (L) of the acceleration tube, and the inclination angle (θ) of the inner surface of the tapered portion may be determined so that the thrust force ratio (p) is greater than the minimum value (pmin).

The thrust force ratio (p) and the yarn speed ratio (q) may be obtained by the estimation expressions f (L, A/L, θ) obtained by multivariate analysis, and the range of the ratio (a/L) of the length (a) of the straight portion to the total length (L) of the acceleration tube may be determined in such a manner that the thrust force ratio (p) is larger than the minimum value (pmin) and the yarn speed ratio (q) is smaller than the maximum value (qmax).

When θ is 0.1, L is 240mm, qmax is 1.15, and pmin is 1.2, 0.13 < a/L is 0.76.

According to the air jet loom of the present invention, the occurrence of weft knots can be prevented and a high weft yarn conveying force can be maintained.

Drawings

Fig. 1 is a schematic cross-sectional view of an acceleration pipe of a main nozzle of an air jet loom of an embodiment of the present invention.

Fig. 2 is a schematic perspective view showing a tip end portion and a thread guide portion of an acceleration tube of a main nozzle of the air jet loom shown in fig. 1.

Fig. 3 is a schematic side view showing a positional relationship between a tip end portion of an acceleration tube and a yarn guide portion of a main nozzle of the air jet loom shown in fig. 2.

Fig. 4 is a cross-sectional view of the main nozzle of the air jet loom shown in fig. 2, in which the acceleration tube and the wire guide are cut along a cutting line IV-IV, and schematically shows the positional relationship between the wire guide and the central axis of the acceleration tube.

Fig. 5A is a diagram schematically showing a state of a weft yarn at the start of weft insertion by an acceleration tube of a main nozzle of the air jet loom shown in fig. 1, and fig. 5B is a diagram schematically showing a state of a weft yarn when a leading end portion of the weft yarn reaches a tunnel entrance of a yarn guide portion.

Fig. 6A is a diagram showing a state where the leading end portion of the weft yarn is bent, and fig. 6B is a diagram showing a state where the bending length of the leading end portion of the weft yarn is maximized.

Fig. 7 is a graph showing the relationship between the ratio a/L and the propulsion force ratio p obtained by the estimation formula f (L, A/L, θ) obtained by multivariate analysis.

Fig. 8 is a graph showing the relationship between the ratio a/L and the yarn speed ratio q obtained by the estimation formula f (L, A/L, θ) obtained by multivariate analysis.

FIG. 9 is a graph showing the relationship between the ratio A/L and the evaluation function F0.

Description of the reference numerals

1 … accelerating tube, 1a … conical part, 1b … straight line part, 7 … wire guide part, 7a … tunnel, 10 … main nozzle, 100 … air jet loom, central shaft of T … accelerating tube, Y … wefting direction

Detailed Description

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in fig. 1, the air jet loom 100 has a main nozzle 10. The main nozzle 10 has: an accelerating tube 1; a first main nozzle bracket 3 supporting the acceleration tube 1; a second main nozzle bracket 5 provided upstream of the first main nozzle bracket 3 and supporting the acceleration pipe 1 via a sleeve 4. In addition, a thread guide 2 is provided on the second main nozzle carrier 5, and the thread guide 2 communicates with the acceleration pipe 1 via a sleeve 4. The thread guide 2 is a member that guides the weft yarn so that the weft yarn is conveyed while being aligned with the central axis T of the acceleration tube 1.

As shown in fig. 1, the acceleration pipe 1 has a tapered portion 1a and a linear portion 1 b. The tapered portion 1a is formed such that the inner diameter increases continuously from the upstream side toward the downstream side. Further, the inclination angle of the inner side surface of the tapered portion 1a is θ. The linear portion 1b is connected to the downstream side of the tapered portion 1a, and is formed in a linear shape so as to have the same diameter from the upstream side to the downstream side. The acceleration tube 1 jets air from the downstream end 1c to the weft. The length of the linear portion 1b is a, and the entire length of the acceleration tube 1 is L.

As shown in fig. 2, the air jet loom 100 includes a yarn guide 7. A tunnel 7a extending in the weft insertion direction Y is formed in the yarn guide 7. The weft yarn 20 is ejected from the tip end 1c of the acceleration tube 1, and flies in the tunnel 7a along the central axis T of the acceleration tube 1 to be inserted.

As shown in fig. 3, the distance between the tip end portion 1c of the acceleration pipe 1 and the entrance of the tunnel 7a of the wire guide portion 7 is c 1. As shown in fig. 4, the shortest distance between the tunnel 7a of the wire guide portion 7 and the central axis T of the acceleration pipe 1 is c 2. Further, a circle E of a broken line shown in fig. 4 shows the position of the acceleration pipe 1.

Next, a method for determining the range of the length a of the linear portion 1b of the acceleration pipe 1 will be described with reference to fig. 5 to 9.

First, as shown in fig. 5(a) and 5(B), a weft yarn 20 is represented by 2 dots P1 and P2 in a simplified model. The yarn speed of an arbitrary point P1 of the weft yarn 20 is U1, and the yarn speed of the downstream leading end P2 of the weft yarn 20 is U2. Here, at the start of weft insertion, the yarn speed U1 of point P1 is faster than the yarn speed U2 of point P2. As shown in fig. 5A, when the leading end P2 of the weft yarn 20 is located at the same position as the leading end 1c of the acceleration tube 1 at the start of weft insertion, the interval between 2 dots P1 and P2 of the weft yarn 20 is D1. Next, as shown in fig. 5B, when the leading end P2 of the weft yarn 20 reaches the entrance of the tunnel 7a of the guide portion 7, the interval between the 2 particles P1 and P2 of the weft yarn 20 is reduced from D1 to D2. Therefore, a curve is generated in the vicinity of the downstream-side leading end of the weft yarn 20.

When the weft yarn 20 is bent in this way, the weft yarn 20 is bent as shown in fig. 6A. As shown in fig. 6A, the length of the weft yarn 20 at the bent portion is set to the bent length S. The distance from the central axis T of the acceleration tube 1 to the tip P2 of the weft yarn 20 is defined as a bending distance h. As shown in fig. 6B, when the bending distance h is substantially the same as the bending length S, that is, the yarn is bent at a right angle, the approach distance between the mass points P1 and P2 is substantially the same as the bending length S, and the bending distance h is the maximum value hmax. Such a kink is mainly generated at the initial stage of the pressure rise immediately after the start of weft insertion in the air jet loom 100.

Here, when the yarn speed ratio q is defined as U1/U2, the following relational expression is established. The time taken for the leading end P2 of the weft yarn 20 to reach the entrance of the tunnel 7a of the yarn guide 7 is t 2. The yarn speed U1/U2 is determined, for example, by the ratio of the amount of work done by air during the time when the yarn enters D1 of 20mm to the amount of increase in kinetic energy of the yarn relative to energy.

[ formula 2]

S＝(U1-U2)*t2

＝U2*(q-1)*(c1/U2)

＝(q-1)*c1

Here, when the leading end P2 of the folded weft yarn 20 comes into contact with the wall of the tunnel 7a of the guide portion 7, the possibility of occurrence of weft knots in the fabric becomes high. Therefore, the condition that the leading end P2 of the folded weft yarn 20 does not contact the wall of the tunnel 7a of the guide portion 7 is expressed by the following relational expression.

[ formula 3]

C2>hmax＝S＝(q-1)*c1

When the yarn speed ratio q is set, the following relationship is established.

[ formula 4]

q<(c2/c1)+1

Therefore, if the yarn speed ratio q is smaller than the maximum value qmax (c2/c1) +1, the leading end P2 of the bent weft yarn 20 does not contact the wall of the tunnel 7a of the yarn guide 7. That is, the condition of the yarn speed ratio q under which the leading end P2 of the folded weft yarn 20 does not contact the lead portion 7, that is, the maximum value qmax of the yarn speed ratio q depends on the positional relationship between the lead portion 7 and the leading end portion 1c of the acceleration tube 1.

Next, in fig. 7, the relationship between the ratio a/L and the thrust force ratio p obtained from the estimation formula f (L, A/L, θ) obtained by the multivariate analysis is graphed. The ratio a/L represents the ratio of the length a of the linear portion 1b to the entire length L of the acceleration pipe 1. Here, the thrust force ratio p is a ratio of the thrust force received by the weft yarn 20 per unit length from the jet fluid when the inner surface of the tapered portion 1a is inclined to form the inclination angle θ, and the thrust force when the inclination angle θ is 0. The minimum value pmin of the thrust force ratio p is determined in accordance with the pressure of the compressed air supplied to the main nozzle 10 or a target value of the opening period of the valve that supplies the compressed air to the main nozzle 10. According to the graph of fig. 7, when the propulsion force ratio p of the acceleration pipe 1 takes the minimum value pmin of 1.2, the ratio a/L is 0.76.

In fig. 8, the relationship between the ratio a/L and the yarn speed ratio q obtained by the estimation formula f (L, A/L, θ) obtained by multivariate analysis is graphed. Here, when the yarn speed ratio q has a maximum value qmax of 1.15 in the case where the distance c1 is 20mm and the distance c2 is 3mm, the ratio a/L is 0.13.

Fig. 9 graphically shows an evaluation function F0 of the ratio a/L when L is 240mm and θ is 0.10. The evaluation function F0 of the ratio A/L is a dimensionless number of 0 to 1 and is represented by the following formula. The evaluation function F1 of the thrust force ratio p is a ratio to an arbitrary sufficiently large value of the thrust force ratio p, and if the thrust force ratio p is smaller than the minimum value pmin, F1 is set to 0. The evaluation function F2 of the yarn speed ratio q U1/U2 is a ratio of an arbitrarily sufficiently large value to the yarn speed ratio q, and when the yarn speed ratio q is larger than the maximum value qmax, F2 is 0.

[ formula 5]

F0＝(F1*F2)^0.5

Therefore, according to fig. 9, when L is 240 and θ is 0.10, the ratio a/L is a value in the range of 0.13 < ratio a/L ≦ 0.76.

Accordingly, the acceleration tube 1 of the air jet loom 100 of the present embodiment includes the tapered portion 1a and the linear portion 1b provided in series with the downstream side of the tapered portion 1 a. Here, the yarn speed ratio q of the weft yarn is obtained from the relationship among the total length L of the acceleration tube 1, the ratio a/L of the length a of the linear portion 1b to the total length L of the acceleration tube 1, and the inclination angle θ of the inner surface of the tapered portion 1 a. The maximum value qmax of the yarn speed ratio q for the values of L, the ratio a/L, and θ is determined to satisfy the following expression by utilizing the relationship between the distance c1 from the downstream end of the acceleration pipe 1 to the wire guide portion 7 and the shortest distance c2 from the central axis T of the acceleration pipe 1 to the tunnel 7a of the wire guide portion 7.

[ formula 6]

qmax＝(c2/c1)+1

The thrust force ratio p applied to the weft yarn by the acceleration tube 1 is determined from the relationship among the total length L of the acceleration tube 1, the ratio a/L of the length a of the linear portion 1b to the total length L of the acceleration tube 1, and the inclination angle θ of the inner surface of the tapered portion 1a, as well as the yarn speed ratio q. The thrust force ratio p is determined so as to be greater than a minimum value pmin determined based on the pressure of the compressed air supplied to the main nozzle 10 or a target value of the opening period of the valve that supplies the compressed air to the main nozzle 10, with respect to the values of L, the ratio a/L, and θ. Here, since the thrust force ratio p is improved by forming the inclination angle θ by inclining the inner side surface of the tapered portion 1a, the pressure of the compressed air supplied to the main nozzle 10 and the opening period of the valve supplying the compressed air to the main nozzle 10 can be reduced accordingly, thereby enabling energy saving.

More specifically, the thrust force ratio p and the yarn speed ratio q are obtained by an estimation equation f (L, A/L, θ) obtained by multivariate analysis. The range of the ratio a/L of the length a of the linear portion 1b to the total length L of the acceleration tube 1 is determined by the range in which the propulsion force ratio p is greater than the minimum value pmin and the yarn speed ratio q is less than the maximum value qmax. As an example of the range of the specific ratio a/L determined in this manner, when θ is 0.1, L is 240mm, qmax is 1.15, and pmin is 1.2, the range of the ratio a/L of the length a of the linear portion 1b to the total length L of the acceleration pipe 1 is 0.13 < the ratio a/L ≦ 0.76.

By appropriately determining the range of the length a of the linear portion 1b of the acceleration tube 1 in this manner, the occurrence of weft knots due to the random movement of the leading end of the weft yarn can be prevented, and the main nozzle 10 can maintain a high weft yarn conveying force

Further, the acceleration pipe 1 and the sleeve 4 may also be integrally formed. This can reduce the number of components of the air jet loom 100. The linear portion 1b of the acceleration pipe 1 may be connected to a linear second acceleration pipe via a joint member. This can lengthen the entire length L of the acceleration tube, and can further improve the weft yarn conveying force.

Claims

1. An air jet loom, comprising:

a guide wire part provided with a tunnel extending in a weft insertion direction; and

a main nozzle for performing weft insertion by flying a weft yarn in the tunnel by air jet injection,

the acceleration tube of the main nozzle has:

a tapered portion having an inner diameter that continuously increases from an upstream side toward a downstream side; and

a straight portion that is provided in connection with a downstream side of the tapered portion and extends so as to have a constant inner diameter from an upstream side to a downstream side,

the weft yarn speed ratio q is a speed ratio U1/U2 of a speed U1 at any point of the weft yarn and a speed U2 at the downstream side of the weft yarn,

the yarn speed ratio q is obtained from a relationship among the total length L of the acceleration tube, the ratio A/L of the length A of the straight portion to the total length L of the acceleration tube, and the inclination angle theta of the inner surface of the tapered portion to the central axis of the acceleration tube,

the values of the total length L of the acceleration tube, the ratio A/L of the length A of the linear portion to the total length L of the acceleration tube, and the inclination angle theta of the inner surface of the tapered portion are determined so that the yarn speed ratio q is smaller than the maximum value qmax of the yarn speed ratio q obtained by the following equation in the relationship between the distance c1 from the downstream-side tip of the acceleration tube to the wire guide portion and the shortest distance c2 from the central axis of the acceleration tube to the tunnel of the wire guide portion,

[ formula 1] is:

qmax＝(c2/c1)+1。

2. the air jet loom of claim 1,

the thrust force ratio p applied to the weft yarn by the acceleration tube is determined by the relationship among the total length L of the acceleration tube, the ratio A/L of the length A of the straight portion to the total length L of the acceleration tube, and the inclination angle theta of the inner surface of the tapered portion,

the thrust force ratio p is a ratio of a thrust force received by the weft yarn per unit length from the jet fluid when the inner surface of the tapered portion is inclined to form the inclination angle theta to a thrust force compared when the inclination angle theta is 0,

the minimum value pmin of the propulsion force ratio p is determined in accordance with the pressure of the compressed air supplied to the main nozzle or a target value of the opening period of a valve that supplies the compressed air to the main nozzle,

the values of the total length L of the acceleration tube, the ratio a/L of the length a of the linear portion to the total length L of the acceleration tube, and the inclination angle θ of the inner surface of the tapered portion are determined so that the thrust force ratio p is larger than the minimum value pmin.

3. The air jet loom of claim 2,

the propulsion force ratio p and the yarn speed ratio q are obtained by an inference formula f (L, A/L, theta) obtained by multivariate analysis,

the range of the ratio a/L of the length a of the straight portion to the total length L of the acceleration tube is determined by the range in which the propulsion force ratio p is larger than the minimum value pmin and the yarn speed ratio q is smaller than the maximum value qmax.

4. The air jet loom of claim 3,

0.13 < A/L.ltoreq.0.76 when θ is 0.1, L is 240mm, qmax is 1.15, and pmin is 1.2.