Weft delivery nozzle for air-jet looms

Abstract

The present invention provides a weft yarn delivery nozzle of an air jet loom capable of further improving the weft yarn propulsion force. Each of the two air guide surfaces (37) has an inner edge (F1) located at the inner peripheral surface of the flow path forming portion (34) and extending in a manner of being recessed toward the base end side of the flow path forming portion (34), and an outer edge (F2) located at the outer peripheral surface of the flow path forming portion (34) and extending in a manner of following the inner edge (F1) more toward the base end side of the flow path forming portion (34) than the inner edge (F1). The two air guide surfaces (37) are disposed equally around the center axis (L1) of the flow path forming portion (34).

Description

TECHNICAL FIELD

[0001] The present application relates to a weft yarn delivery nozzle of an air jet loom. BACKGROUND

[0002] In an air jet loom, a weft yarn is inserted to a weft yarn delivery nozzle by an air jet action of a main nozzle for weft insertion. The weft yarn delivery nozzle is provided with a guide and an acceleration tube.

[0003] The guide divides a weft yarn passage for the weft yarn insertion in the inside, and is provided with a conical cylinder shaped flow path forming portion at the outlet side of the weft yarn passage. The acceleration tube is provided with a conical cylinder shaped flow path dividing portion which surrounds the flow path forming portion, and divides a draft passage in front of the outlet of the weft yarn passage in the weft insertion direction of the weft yarn. Further, an annular air flow path is divided between the outer peripheral surface of the flow path forming portion and the inner peripheral surface of the flow path dividing portion. The flow path sectional area of the air flow path becomes smaller as it goes from the base end side of the flow path forming portion toward the front end. The air flowing out of the air flow path is accelerated by the change in the flow path sectional area of the air flow path.

[0004] The weft yarn inserted to the weft yarn passage passes through the draft passage in the acceleration tube. The weft yarn is accelerated by the air from the air flow path in the draft passage in the acceleration tube in front of the front end of the guide, and is carried by the air.

[0005] In order to improve the propulsion force of the weft yarn in the draft passage, for example, a threading nozzle 80 disclosed in Patent Document 1 is provided with a plurality of notches 82 at the front end of a guide 81 as shown in Figure 13 and Figure 14 The notches 82 are formed so as to gradually narrow from the front end of the guide 81 toward a root side end portion 82a which becomes the base end. By the notches 82, the sharp expansion of the air flowing out of the air flow path 83 is avoided when it flows into the draft passage 84. Since the sharp expansion of the air in the threading nozzle 80 is avoided, the generation of turbulence is prevented, so the propulsion force of the weft yarn is improved.

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 9-21035

[0007] However, in the threading nozzle 80 of Patent Document 1, although the sharp expansion of the air is avoided by the notches 82, in the root side end portion 82a of the notches 82, the flow path sectional area of the air flow path 83 changes sharply. As a result, in the vicinity of the root side end portion 82a of the notches 82, the flow of the air becomes turbulent, and the air flows backward toward the inside of the guide 81, so the improvement of the propulsion force of the weft yarn is not sufficient. SUMMARY

[0008] The gist of the weft yarn delivery nozzle of the air jet loom for solving the above-described problems is to have: a guide, which divides a weft yarn passage through which a weft yarn is inserted, and has a flow path forming portion at an outlet side of the weft yarn passage; and an acceleration tube, which has a flow path dividing portion that surrounds the flow path forming portion, and divides a draft passage in a weft insertion direction of the weft yarn in front of the outlet of the weft yarn passage, divides an annular air flow path between an outer peripheral surface of the flow path forming portion and an inner peripheral surface of the flow path dividing portion, the air flow path communicates with the draft passage at an outlet of the air flow path, and the flow path cross-sectional area decreases as it goes from an inlet of the air flow path toward the outlet of the air flow path, wherein the guide has a plurality of air guide surfaces at a front end of the flow path forming portion, each of the plurality of air guide surfaces has an inner edge that is located at the inner peripheral surface of the flow path forming portion and extends in a manner that is recessed toward a base end side of the flow path forming portion, and an outer edge that is located at the outer peripheral surface of the flow path forming portion and extends in a manner that follows the inner edge toward the base end side of the flow path forming portion than the inner edge, and the plurality of air guide surfaces are equally arranged around a central axis of the flow path forming portion.

[0009] Thus, the air flowing out from the outlet of the air flow path toward the draft passage is guided by the air guide surfaces so as to be directed toward the central axis of the draft passage. Therefore, it is possible to suppress a case where the air flowing in the air flow path is reversed toward the base end side of the flow path forming portion and flows back to the weft yarn passage. Therefore, it is possible to suppress a decrease in the weft yarn advancing force caused by the backflow of the air, and it is possible to increase the weft yarn advancing force. In addition, by the plurality of air guide surfaces that are equally arranged, the air flowing out from the outlet of the air flow path toward the draft passage is uniformly dispersed into a plurality of air flows. Thus, it is possible to suppress the size of the shock wave generated by the air flowing out from the outlet of the air flow path. Therefore, it is possible to suppress a decrease in the weft yarn advancing force caused by the shock wave in the acceleration tube. Therefore, it is possible to further increase the weft yarn advancing force generated by the air jet action of the weft insertion main nozzle by the plurality of air guide surfaces that are equally arranged.

[0010] As for the weft yarn delivery nozzle of the air jet loom, it is also possible to have two of the air guide surfaces.

[0011] Thus, the fewer the number of air guide surfaces, the easier it is for the air flowing out from the outlet of the air flow path toward the draft passage to be dispersed. Therefore, it is possible to further suppress the size of the shock wave generated by the air flowing out from the outlet of the air flow path by the two air guide surfaces.

[0012] With respect to the weft yarn delivery nozzle of the air jet loom, the two air guide surfaces can also be disposed sandwiching an imaginary line orthogonal to the center axis of the flow path forming portion, and the cross section of the air guide surface around the center axis and orthogonal to the imaginary line can be a curved surface that bulges toward the front of the weft insertion direction as it moves from the base end side of the flow path forming portion toward the imaginary line.

[0013] Accordingly, the air flowing out of the outlet of the air flow path is guided by the air guide surface so as to flow along the center axis of the draft passage.

[0014] According to the present application, the weft yarn advancing force can be further improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a cross-sectional view of a weft yarn delivery nozzle that represents an embodiment.

[0016] Figure 2 is a partial cross-sectional view of the periphery of an air guide surface.

[0017] Figure 3 is a partial perspective view of an air guide surface.

[0018] Figure 4 is a partial cross-sectional view of a precursor and a flow path forming portion.

[0019] Figure 5 is a partial cross-sectional view of an embodiment of another example of an air guide surface.

[0020] Figure 6 is a partial perspective view of an embodiment of another example of an air guide surface.

[0021] Figure 7 is a partial cross-sectional view of an embodiment of another other example of an air guide surface.

[0022] Figure 8 is a partial perspective view of an embodiment of another other example of an air guide surface.

[0023] Figure 9 is a partial cross-sectional view of an embodiment of another other example of an air guide surface.

[0024] Figure 10 is a partial perspective view of an embodiment of another other example of an air guide surface.

[0025] Figure 11 is a partial cross-sectional view of an embodiment of another other example of an air guide surface.

[0026] Figure 12is a partial perspective view of another embodiment of the air guide surface.

[0027] Figure 13 is a diagram showing the background art.

[0028] Figure 14 is a diagram showing the root side end portion of the notch.

[0029] Explanation of Reference Signs

[0030] B…imaginary line, F1…inner edge, F2…outer edge, L, L1…center axis, Y…weft yarn, Z…weft insertion direction, 10…weft yarn delivery nozzle, 20…accelerating tube, 22…flow path dividing portion, 26…traction passage, 30…guide, 30a…weft yarn passage, 34…flow path forming portion, 37…air guide surface, 50…air flow path, 50a…inlet, 50b…outlet. DETAILED DESCRIPTION

[0031] Hereinafter, an embodiment of a weft yarn delivery nozzle of an air jet loom will be explained based on Figures 1-4

[0032] [Overall of Weft Yarn Delivery Nozzle]

[0033] Although not shown, in an air jet loom, a weft yarn is inserted into a weft yarn delivery nozzle by the air jet action of a main nozzle for weft insertion.

[0034] As shown in Figure 1 , the weft yarn delivery nozzle 10 is provided with a nozzle body 11, an accelerating tube 20, and a guide 30.

[0035] <Nozzle Body>

[0036] The nozzle body 11 is cylindrical. A through-hole 12 is formed in the nozzle body 11 so as to pass through in the axial direction X of the nozzle body 11. The axial direction X of the nozzle body 11 is the direction in which the center axis of the nozzle body 11 extends. The nozzle body 11 is provided with a first end surface 11a at one end in the axial direction X, and a second end surface 11b at the other end in the axial direction X. The nozzle body 11 is provided with an internal thread 13, a first dividing surface 14, a second dividing surface 15, and a step surface 16 arranged in the axial direction X, and is provided with a connection port 17 extending in a direction intersecting the axial direction X.

[0037] ​The female screw 13 is formed between the first end surface 11a of the inner peripheral surface of the nozzle body 11 and the first division surface 14. The inner diameter of the first division surface 14 of the nozzle body 11 is larger than the inner diameter of the second division surface 15 of the nozzle body 11. The first division surface 14 divides a large-diameter hole 14a on the inner side of the nozzle body 11. The second division surface 15 divides a small-diameter hole 15a on the inner side of the nozzle body 11. A step surface 16 is formed at the boundary of the first division surface 14 and the second division surface 15. A connection port 17 is opened toward the large-diameter hole 14a. The connection port 17 communicates the inside of the nozzle body 11 with the outside. An air supply tube 18 is connected to the connection port 17.

[0038] <Acceleration pipe>

[0039] The acceleration pipe 20 is cylindrical. The axis direction of the acceleration pipe 20 coincides with the axis direction X of the nozzle body 11. Therefore, the axis direction of the acceleration pipe 20 is described as "axis direction X". The acceleration pipe 20 has a flow path division portion 22 and a small-diameter cylindrical portion 23 arranged in the axis direction X. The outer diameter of the flow path division portion 22 is larger than the outer diameter of the small-diameter cylindrical portion 23. The outer diameter of the flow path division portion 22 is slightly smaller than the hole diameter of the large-diameter hole 14a. The outer diameter of the small-diameter cylindrical portion 23 is slightly smaller than the outer diameter of the small-diameter hole 15a. The flow path division portion 22 is inserted into the inner side of the nozzle body 11 in the large-diameter hole 14a, and the small-diameter cylindrical portion 23 is inserted into the inner side of the nozzle body 11 in the small-diameter hole 15a. The boundary portion of the flow path division portion 22 and the small-diameter cylindrical portion 23 is in contact with the step surface 16. By this contact, the case where the acceleration pipe 20 is detached from the nozzle body 11 is suppressed.

[0040] The acceleration pipe 20 has a tapered inner peripheral surface 24 and a passage division surface 25. The tapered inner peripheral surface 24 is opened at an end surface 20a of the flow path division portion 22 of the acceleration pipe 20. The inner diameter of the tapered inner peripheral surface 24 of the acceleration pipe 20 is reduced toward the passage division surface 25 from the end surface 20a. The inner diameter of the passage division surface 25 of the acceleration pipe 20 is constant. A traction passage 26 is divided on the inner side of the acceleration pipe 20 by the passage division surface 25. The passage diameter of the traction passage 26 is constant in the axis direction X. In addition, the center axis L of the traction passage 26 coincides with the center axis of the acceleration pipe 20.

[0041] <Guide>

[0042] The guide 30 is cylindrical. The guide 30 divides a weft passage 30a through which the weft Y is inserted. A direction in which the weft Y flies is described as a weft insertion direction Z. The "front" in the weft insertion direction Z is a direction in which the weft Y advances. An axial direction of the guide 30 coincides with the axial direction X of the nozzle body 11. Therefore, the axial direction of the guide 30 is described as the "axial direction X". The guide 30 includes an external thread 31 arranged in the axial direction X, a base 32, fins 33, a flow path forming portion 34, and a plurality of air guide surfaces 37. The external thread 31 is screwed into the internal thread 13 of the nozzle body 11. The base 32 is cylindrical. An outer diameter of the base 32 of the guide 30 is slightly smaller than a hole diameter of the large-diameter hole 14a. An outer peripheral surface of the base 32 contacts the first division surface 14, and the base 32 is fitted inside the nozzle body 11 in the large-diameter hole 14a.

[0043] The fins 33 are apart from the base 32 in the axial direction X of the guide 30. The fins 33 are provided at equal intervals in a circumferential direction of the guide 30. An outer diameter of the fins 33 of the guide 30 is slightly smaller than the hole diameter of the large-diameter hole 14a. An outer peripheral surface of the guide 30 of each of the fins 33 contacts the first division surface 14, and each of the fins 33 is fitted inside the nozzle body 11 in the large-diameter hole 14a.

[0044] As shown in Figs. 1 and 2, the flow path forming portion 34 is provided with a plurality of air guide surfaces 37. The air guide surfaces 37 are provided at equal intervals in the circumferential direction of the guide 30. The air guide surfaces 37 are provided on the outer peripheral surface of the flow path forming portion 34. The air guide surfaces 37 are provided on the outer peripheral surface of the flow path forming portion 34 so as to be apart from each other in the axial direction X of the guide 30. The air guide surfaces 37 are provided on the outer peripheral surface of the flow path forming portion 34 so as to be apart from each other in the axial direction X of the guide 30. The air guide surfaces 37 are provided on the outer peripheral surface of the flow path forming portion 34 so as to be apart from each other in the axial direction X of the guide 30. Figure 1 Figure 2 As shown in Figs. 1 and 2, the flow path forming portion 34 is provided with a plurality of air guide surfaces 37. The air guide surfaces 37 are provided at equal intervals in the circumferential direction of the guide 30. The air guide surfaces 37 are provided on the outer peripheral surface of the flow path forming portion 34. The air guide surfaces 37 are provided on the outer peripheral surface of the flow path forming portion 34 so as to be apart from each other in the axial direction X of the guide 30. The air guide surfaces 37 are provided on the outer peripheral surface of the flow path forming portion 34 so as to be apart from each other in the axial direction X of the guide 30. The air guide surfaces 37 are provided on the outer peripheral surface of the flow path forming portion 34 so as to be apart from each other in the axial direction X of the guide 30.

[0045] Most of the flow path forming portion 34 is inserted inside the flow path division portion 22. Therefore, the acceleration pipe 20 includes the flow path division portion 22 that surrounds the flow path forming portion 34. An annular air flow path 50 is formed between the outer peripheral surface of the flow path forming portion 34 and the conical inner peripheral surface 24 of the flow path division portion 22.

[0046] The air supplied from the air supply pipe 18 flows into the air flow path 50. Specifically, the air supplied from the air supply pipe 18 into the nozzle body 11 is supplied between the base 32 and the fins 33 of the guide 30, and passes between the fins 33 to be supplied to the air flow path 50. The pressure of the air flowing in the air flow path 50 is adjusted by adjusting the pressure of the air supplied from the air supply pipe 18. The greater the pressure of the air supplied from the air supply pipe 18, the higher the flow rate of the air flowing in the air flow path 50 can be increased.

[0047] ​The airflow path 50 is the portion of the outer peripheral surface of the flow path forming section 34 extending from the position corresponding to the end face 20a of the acceleration tube 20 to the front end of the flow path forming section 34. The airflow path 50 has an inlet 50a and an outlet 50b. The inlet 50a is located between the outer peripheral surface of the flow path forming section 34 and the conical inner peripheral surface 24. The outlet 50b is located between the front end of the flow path forming section 34 and the conical inner peripheral surface 24. The airflow path 50 communicates with the traction passage 26 at its outlet 50b.

[0048] The cross-sectional area of ​​the airflow path 50 gradually decreases from the inlet 50a towards the outlet 50b. Therefore, the airflow path 50 functions as a throttle valve at the outlet 50b. Furthermore, through this throttle valve function, the air velocity is increased when air is discharged from the outlet 50b of the airflow path 50. The air flowing in the airflow path 50 is supplied from the outlet 50b to the traction passage 26.

[0049] A weft yarn passage 30a extending along the axial direction X is formed inside the yarn guide 30. The weft yarn Y is inserted into the weft yarn passage 30a. The inlet of the weft yarn passage 30a opens on the first end face 11a side of the nozzle body 11. The outlet of the weft yarn passage 30a opens in the traction passage 26. Therefore, the yarn guide 30 has a flow path forming part 34 on the outlet side of the weft yarn passage 30a. In addition, the acceleration tube 20 divides the traction passage 26 in the weft insertion direction Z of the weft yarn Y ahead of the outlet of the weft yarn passage 30a.

[0050] The weft yarn passage 30a is connected to the traction passage 26. The weft yarn Y is inserted into the weft yarn passage 30a by air jetting from a main weft insertion nozzle (not shown). The weft yarn Y inserted into the weft yarn passage 30a flies along the weft insertion direction Z. The weft yarn Y flies in the traction passage 26 ahead of the exit of the weft yarn passage 30a in the weft insertion direction Z. The weft yarn Y is accelerated by air from the airflow path 50 and carried by the airflow. This applies a propulsive force to the weft yarn Y.

[0051] <Air Guide Surface>

[0052] like Figure 2 , Figure 3 as well as Figure 4 As shown, two air guiding surfaces 37 are provided at the front end of the flow path forming section 34. Each of the two air guiding surfaces 37 has an inner edge F1 and an outer edge F2.

[0053] A pair of inner peripheral ends T1 are present at the front end of the flow path forming section 34. The pair of inner peripheral ends T1 are located on the inner peripheral edge of the flow path forming section 34. In addition, a pair of outer peripheral ends T2 are present at the outer peripheral edge of the flow path forming section 34. The inner peripheral ends T1 and the outer peripheral ends T2 are located at the boundary of the two air guiding surfaces 37.

[0054] Two front edges 36 that link the inner peripheral end T1 and the outer peripheral end T2 are formed in the flow path forming portion 34. Each front edge 36 links the inner peripheral end T1 and the outer peripheral end T2 in the radial direction of the flow path forming portion 34. If an imaginary line G passing through the front edge 36 is extended in the radial direction of the flow path forming portion 34, the imaginary line G is orthogonal to the central axis L of the weft drawing passage 26. Two front edges 36 are formed in the front end of the flow path forming portion 34. The two front edges 36 are located at the boundary of the two air guide surfaces 37. Further, the air guide surface 37 including the front edge 36 is inclined with respect to the weft direction Z.

[0055] The inner edge F1 is located in the inner peripheral surface of the flow path forming portion 34. The inner edge F1 is a curve that links the pair of inner peripheral ends T1 in the circumferential direction of the flow path forming portion 34. In addition, the inner edge F1 is an opening edge that extends along the outlet of the weft passage 30a. The inner edge F1 extends toward the base end side of the flow path forming portion 34 in a manner that is concave in a circular arc shape. The outer edge F2 is located in the outer peripheral surface of the flow path forming portion 34. The outer edge F2 is a curve that links the pair of outer peripheral ends T2 in the circumferential direction of the flow path forming portion 34. In addition, the outer edge F2 extends in the circumferential direction of the flow path forming portion 34 in a manner that follows the inner edge F1 on the base end side of the flow path forming portion 34 than the inner edge F1. Each air guide surface 37 is formed in a surface that links the inner edge F1 and the outer edge F2. In detail, each air guide surface 37 is a surface surrounded by the pair of front edges 36, the inner edge F1, and the outer edge F2.

[0056] Therefore, each of the two air guide surfaces 37 has the inner edge F1 that extends in a manner that is concave toward the base end side of the flow path forming portion 34, and the outer edge F2 that is located in the outer peripheral surface of the flow path forming portion 34 and extends in a manner that follows the inner edge F1 on the base end side of the flow path forming portion 34 than the inner edge F1.

[0057] A point on the outer edge F2 and an intermediate position of the two outer peripheral ends T2 are taken as an intermediate point FP. In addition, a surface in which the two inner peripheral ends T1 are located and the central axis L1 of the flow path forming portion 34 is orthogonal is taken as a front end imaginary surface N1. Further, a surface passing through the two inner peripheral ends T1 and the intermediate point FP is taken as an imaginary surface H. The imaginary surface H is obliquely intersected with the front end imaginary surface N1. Since the two inner peripheral ends T1 are formed in the flow path forming portion 34, the two intermediate points FP are also formed in the flow path forming portion 34. Therefore, the two imaginary surfaces H are formed in the flow path forming portion 34. Further, the two imaginary surfaces H are intersected with the front end imaginary surface N1 at an inclination angle θ. In the flow path forming portion 34, the air guide surface 37 is formed along each imaginary surface H.

[0058] The air guide surface 37 is a surface inclined at an inclination angle θ with respect to the front end imaginary surface Nl. The length of the inner edge Fl, which is the dimension linking the two inner peripheral ends Tl in the circumferential direction of the flow path forming portion 34, is set as the inner edge length of the air guide surface 37. The inner edge lengths of the two air guide surfaces 37 are equal to each other. In addition, the length of the outer edge F2, which is the dimension linking the two outer peripheral ends T2 in the circumferential direction of the flow path forming portion 34, is set as the outer edge length of the air guide surface 37. The outer edge lengths of the two air guide surfaces 37 are equal to each other. That is, the dimensions of the two air guide surfaces 37 in the circumferential direction of the flow path forming portion 34 are equal to each other. Therefore, the two air guide surfaces 37 are disposed equally around the center axis Ll of the flow path forming portion 34. In other words, the air guide surfaces 37 are disposed equally without being inclined around the center axis Ll.

[0059] As Figure 4 The material before the air guide surfaces 37 are formed is shown by the two-dot chain line as the precursor 90. The precursor 90 is a conical cylindrical shape in which each of the outer peripheral surface and the inner peripheral surface of the flow path forming portion 34 is elongated toward the front end imaginary surface Nl. The center axis of the precursor 90 is also the center axis Ll of the flow path forming portion 34, and is described as "the center axis Ll of the precursor 90". The inner diameter of the precursor 90 is constant in the axial direction X, and the outer diameter of the precursor 90 gradually decreases as it goes from the base end side of the precursor 90 toward the front end.

[0060] In the precursor 90, two inner peripheral ends Tl are set on the front end imaginary surface Nl. The two inner peripheral ends Tl are set at the inner peripheral edge of the precursor 90, and are set at positions diametrically opposite to the flow path forming portion 34. In addition, an intermediate point FP is set on the outer peripheral surface on the base end side of the precursor 90 than the front end imaginary surface Nl. In the cross section of the precursor 90 along the center axis Ll, the intermediate point FP is an intersection point of the imaginary surface H inclined at an inclination angle θ with respect to the front end imaginary surface Nl and the outer peripheral surface of the precursor 90. Two intermediate points FP are set on the outer peripheral surface of the precursor 90. Furthermore, if the precursor 90 is cut along the imaginary surface H passing through the intermediate points FP and the two inner peripheral ends Tl, the air guide surfaces 37 are formed. Each air guide surface 37 is inclined from the outlet side of the weft yarn passage 30a toward the inlet side of the weft yarn passage 30a.

[0061] [Effects of Embodiments]

[0062] The weft yarn Y passing through the weft yarn passage 30a of the guide 30 and the draft passage 26 of the accelerating tube 20 is subjected to a propulsive force caused by the air jet action of the main weft nozzle in the draft passage 26 in front of the air guide surface 37 in the weft direction Z. The air flowing out of the outlet 50b of the air flow path 50 is guided by each air guide surface 37 so as to flow toward the central axis L of the draft passage 26. In addition, the air around the outlet of the weft yarn passage 30a does not flow in a circular shape concentric with the annular air flow path 50, but is uniformly dispersed into two air streams by each air guide surface 37. Therefore, the size of the shock wave generated in the accelerating tube 20 can be suppressed by the air flowing out of the outlet 50b of the air flow path 50. Moreover, the two air guide surfaces 37 are disposed equally around the central axis Ll, so the air becomes an air stream that is not deflected in the circumferential direction of the flow path forming portion 34 and is uniformly dispersed.

[0063] [Effects of Embodiments]

[0064] According to the above-described embodiments, the following effects can be obtained.

[0065] (1) The air flowing out of the air flow path 50 toward the base end side of the flow path forming portion 34 toward the weft yarn passage 30a can be suppressed by the air guide surface 37. Therefore, the decrease in the propulsive force of the weft yarn Y caused by the backflow of air can be suppressed, and the propulsive force of the weft yarn Y can be further increased. In addition, the size of the shock wave generated by the air flowing out of the outlet 50b of the air flow path 50 can be suppressed by the two air guide surfaces 37 disposed equally. Therefore, the decrease in the propulsive force of the weft yarn Y caused by the shock wave can be suppressed. Thus, the propulsive force of the weft yarn Y generated by the air jet action of the main weft nozzle can be further increased by the two air guide surfaces 37 disposed equally. Moreover, since it is not necessary to increase the pressure supplied to the air flow path 50 in order to increase the propulsive force of the weft yarn Y, an increase in energy consumption for increasing the pressure can also be suppressed.

[0066] (2) Two air guide surfaces 37 are provided at the front end of the flow path forming portion 34. The fewer the number of air guide surfaces 37, the more difficult it is for the air flowing out of the air flow path 50 to flow in a concentric circular shape in front of the outlet of the weft yarn passage 30a in the weft direction Z. Therefore, the size of the shock wave can be further suppressed by the two air guide surfaces 37. As a result, the propulsive force of the weft yarn Y can be further increased.

[0067] (3) The size of the shock wave generated by the air flowing out of the outlet 50b of the air flow path 50 can be suppressed by the air guide surface 37. Therefore, the adverse effects of the air flowing out of the air flow path 50 on the weft yarn Y can be suppressed, and the opening of the weft yarn Y can be suppressed in the case where the weft yarn Y is a filament yarn.

[0068] (4) The air guide surfaces 37 can guide the air flowing out of the air flow path 50 in a manner so as to be directed toward the central axis L of the draft passage 26. Therefore, the weft yarn Y flies in a manner so as to follow the central axis L of the draft passage 26. As a result, it is possible to suppress the collision of the weft yarn Y with the inner peripheral surface of the acceleration tube 20, so it is possible to suppress the quality reduction of the weft yarn Y.

[0069] The present embodiment can be implemented by being changed as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a range in which they are not technically contradictory.

[0070] As shown in Figs. 1 and 2, the air guide surfaces 37 can be provided at the front end of the flow path forming portion 34. In this case, each of the air guide surfaces 37 has an inner edge F1 and an outer edge F2. The inner edge F1 is provided at the front end of the flow path forming portion 34. The outer edge F2 is provided at the rear end of the flow path forming portion 34. The inner edge F1 and the outer edge F2 are arranged so as to be spaced apart by 120 degrees in the circumferential direction of the flow path forming portion 34. Figure 5 Figure 6 As shown in Figs. 1 and 2, the air guide surfaces 37 can be provided at the front end of the flow path forming portion 34. In this case, each of the air guide surfaces 37 has an inner edge F1 and an outer edge F2. The inner edge F1 is provided at the front end of the flow path forming portion 34. The outer edge F2 is provided at the rear end of the flow path forming portion 34. The inner edge F1 and the outer edge F2 are arranged so as to be spaced apart by 120 degrees in the circumferential direction of the flow path forming portion 34.

[0071] In addition, eight front edges 36 are provided at the front end of the flow path forming portion 34. If an imaginary line G passing through each of the front edges 36 is extended in the radial direction of the flow path forming portion 34, the imaginary line G is obliquely intersected with the central axis L of the draft passage 26.

[0072] Although not shown, three imaginary surfaces H are formed. Furthermore, the three imaginary surfaces H are obliquely intersected with the front end imaginary surface N1 at an oblique angle θ. At the front end portion of the flow path forming portion 34, the air guide surfaces 37 are formed along each of the imaginary surfaces H. The air guide surfaces 37 are surfaces that are inclined at the oblique angle θ with respect to the front end imaginary surface N1. The three air guide surfaces 37 are equal in length. Therefore, the three air guide surfaces 37 are equally provided around the central axis L1.

[0073] As shown in Figs. 1 and 2, the air guide surfaces 37 can be provided at the front end of the flow path forming portion 34. In this case, each of the air guide surfaces 37 has an inner edge F1 and an outer edge F2. The inner edge F1 is provided at the front end of the flow path forming portion 34. The outer edge F2 is provided at the rear end of the flow path forming portion 34. The inner edge F1 and the outer edge F2 are arranged so as to be spaced apart by 120 degrees in the circumferential direction of the flow path forming portion 34. Figure 7 Figure 8 As shown in Figs. 1 and 2, the air guide surfaces 37 can be provided at the front end of the flow path forming portion 34. In this case, each of the air guide surfaces 37 has an inner edge F1 and an outer edge F2. The inner edge F1 is provided at the front end of the flow path forming portion 34. The outer edge F2 is provided at the rear end of the flow path forming portion 34. The inner edge F1 and the outer edge F2 are arranged so as to be spaced apart by 120 degrees in the circumferential direction of the flow path forming portion 34.

[0074] In addition, eight front edges 36 are provided at the front end of the flow path forming portion 34. If an imaginary line G passing through each of the front edges 36 is extended in the radial direction of the flow path forming portion 34, the imaginary line G is obliquely intersected with the central axis L of the draft passage 26.

[0075] ​​Although not shown, eight imaginary planes H are formed. Moreover, the eight imaginary planes H intersect the front end imaginary plane Nl at an inclination angle θ. In the front end portion of the flow path forming portion 34, air guide surfaces 37 are formed along the imaginary planes H. The air guide surfaces 37 are surfaces inclined at the inclination angle θ with respect to the front end imaginary plane Nl. The eight air guide surfaces 37 are equal in circumference. Therefore, the eight air guide surfaces 37 are equally arranged around the central axis Ll.

[0076] The number of the air guide surfaces 37 can also be appropriately changed.

[0077] As shown in Figs. 6 and 7, the two air guide surfaces 37 are arranged with each sandwiching an imaginary line B orthogonal to the central axis Ll of the flow path forming portion 34. The cross section of the air guide surface 37 around the central axis Ll and orthogonal to the imaginary line B is a curved surface that bulges toward the front in the weft direction Z as it goes from the base end side of the flow path forming portion 34 toward the imaginary line B. Figure 9 Figure 10 As shown in Figs. 6 and 7, the two air guide surfaces 37 are arranged with each sandwiching an imaginary line B orthogonal to the central axis Ll of the flow path forming portion 34. The cross section of the air guide surface 37 around the central axis Ll and orthogonal to the imaginary line B is a curved surface that bulges toward the front in the weft direction Z as it goes from the base end side of the flow path forming portion 34 toward the imaginary line B.

[0078] Thus, the air flowing in the air flow path 50 is guided by the air guide surfaces 37 so as to flow smoothly along the central axis Ll of the flow path forming portion 34 and the central axis L of the draft passage 26. Therefore, generation of turbulence can be suppressed.

[0079] As shown in Figs. 6 and 7, the two air guide surfaces 37 are arranged with each sandwiching an imaginary line B orthogonal to the central axis Ll of the flow path forming portion 34. The cross section of the air guide surface 37 around the central axis Ll and orthogonal to the imaginary line B is a curved surface that bulges toward the front in the weft direction Z as it goes from the base end side of the flow path forming portion 34 toward the imaginary line B. Figure 11 Figure 12 As shown in Figs. 6 and 7, the two air guide surfaces 37 are arranged with each sandwiching an imaginary line B orthogonal to the central axis Ll of the flow path forming portion 34. The cross section of the air guide surface 37 around the central axis Ll and orthogonal to the imaginary line B is a curved surface that bulges toward the front in the weft direction Z as it goes from the base end side of the flow path forming portion 34 toward the imaginary line B.

[0080] The angle at which the air guide surfaces 37 are inclined can also be appropriately changed.​​

Claims

1. A weft yarn delivery nozzle of an air jet loom, comprising: a guide, which divides a weft yarn passage through which a weft yarn is inserted, and which has a flow path forming portion at an outlet side of the weft yarn passage; and an acceleration tube, which has a flow path dividing portion that surrounds the flow path forming portion, and which divides a draft passage in front of the outlet of the weft yarn passage in a weft insertion direction of the weft yarn, an annular air flow path is divided between an outer peripheral surface of the flow path forming portion and an inner peripheral surface of the flow path dividing portion, the air flow path communicates with the draft passage at an outlet of the air flow path, and a flow path cross-sectional area of the air flow path decreases as it goes from an inlet of the air flow path toward the outlet of the air flow path, characterized in that the guide has a plurality of air guide surfaces at a leading end of the flow path forming portion, each of the plurality of air guide surfaces has an inner edge that is located at the inner peripheral surface of the flow path forming portion and extends in a manner that is recessed toward a base end side of the flow path forming portion, and an outer edge that is located at the outer peripheral surface of the flow path forming portion and extends in a manner that is along the inner edge toward the base end side of the flow path forming portion than the inner edge, and the plurality of air guide surfaces are disposed equally around a central axis of the flow path forming portion.

2. The weft yarn delivery nozzle of an air jet loom according to claim 1, characterized in that two of the air guide surfaces are provided.

3. The weft yarn delivery nozzle of an air jet loom according to claim 2, characterized in that the two air guide surfaces are disposed sandwiching an imaginary line that is orthogonal to the central axis of the flow path forming portion, and a cross section of the air guide surfaces around the central axis and orthogonal to the imaginary line is a curved surface that bulges toward a front of the weft insertion direction as it goes from the base end side of the flow path forming portion toward the imaginary line. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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