Yarn forming element

Abstract

The invention relates to a yarn forming element for an air-jet spinning nozzle comprising a spinning cone with a conical tip, a first end face with an inlet opening, a channel body, and a second end face with an outlet opening, wherein the channel body and the spinning cone are connected to each other, and a passage through which the channel body and the spinning cone pass to connect the inlet opening with the outlet opening. To provide a yarn forming element that is particularly cost-effective and easy to manufacture, the spinning cone has a truncated cone-shaped segment extending towards the second end face with an increasing distance between its inner surface and an outer surface of the channel body radially limiting the passage, thus forming a gap.

Description

[0001] The invention relates to a yarn-forming element, an air-jet spinneret comprising such a yarn-forming element, and a method for producing such a yarn-forming element. Yarn-forming elements for spinning devices, in particular for air-jet spinning devices, are known in a wide variety of designs from the prior art. Yarn-forming elements are used to produce an air-jet spun thread from a fiber sliver coming from a drafting system, which is fed in a controlled manner into a spinneret comprising the yarn-forming element. Compressed spinning air is fed into the spinneret to generate a swirling air flow. The air-jet spun thread is discharged from the spinneret via the yarn-forming element.

[0002] A yarn-forming element is known, for example, from the publications EP 3 293 294 A1, WO 2010 / 034416 A1, EP 2 573 218 A2, EP 3 428 330 A1, JP 2017 025437 A, EP 3 115 485 A1, and CH 679 491 A5, in which the yarn-forming element is formed from several assembled components. Due to the fluid flows used for spinning, on the one hand for spinning the fiber sliver into a thread using spinning compressed air and, on the other hand, for discharging the air-spun thread, a particularly precise and tight connection must be established between the individual components, necessitating particularly complex and cost-intensive manufacturing with very tight tolerances.

[0003] In addition to the problem that the components have to be connected particularly tightly, the yarn forming elements of the state of the art also have the disadvantage that fibers can get caught at the separation points or seams of the individual components and are thereby detached from the thread, which can impair the strength of the thread and also lead to an accumulation of detached fibers at the separation points, which can also impair the spinning result.

[0004] The invention is therefore based on the object of providing a yarn-forming element that can be manufactured at least cost-effectively and, in particular, is also simple in design. Furthermore, the yarn-forming element proposed by the invention should preferably enable a spinning process with improved precision and efficiency, in particular reducing contamination from detached fibers during the spinning operation and the piecing process.

[0005] The object is achieved by a yarn-forming element according to claim 1, an air spinneret according to claim 12, and a method according to claim 13. Advantageous developments of the invention are specified in the dependent claims.

[0006] The yarn-forming element for an air spinneret according to the present invention comprises a spinning cone with a cone tip forming a first end face with an inlet opening for receiving a yarn. Furthermore, a channel body is provided, which has a second end face with an outlet opening for discharging a yarn from the yarn-forming element, wherein the channel body and the spinning cone are connected to one another. A passage passes through the channel body and the spinning cone to connect the inlet opening to the outlet opening for passing the yarn. The yarn received by the inlet opening can thus be guided via the passage to the outlet opening and discharged from the outlet opening of the yarn-forming element.

[0007] The yarn-forming element is characterized in that the spinning cone has a truncated cone-shaped sub-segment which extends in the direction of the second end face with increasing distance between its inner surface and an outer surface of the channel body radially delimiting the passage, forming an intermediate space. This allows the yarn-forming element to be designed in a manner that at least saves material and is therefore more cost-effective. The truncated cone-shaped sub-segment can preferably be arranged adjacent to a sub-segment forming the cone tip, either directly or via at least one additional sub-segment in between. This allows the conical region of the spinning cone to be configured as required in a direction pointing from the inlet opening to the outlet opening, for example, taking into account the fiber length to be spun, whether short, medium, or long staple fibers.

[0008] According to a preferred embodiment of the present invention, the spinning cone has a cylindrical sub-segment into which the truncated cone-shaped sub-segment merges on its side facing away from the cone tip, wherein an inner surface of the cylindrical sub-segment is spaced from the outer surface of the channel body, continuing the formed intermediate space. The yarn-forming element can thus also be provided with a horizontal, outer stop surface in a material-saving manner, via which the yarn-forming element can be suitably and very precisely positioned within the spinneret relative to a fiber sliver feed of the spinneret, via which the fiber sliver is fed to the yarn-forming element.

[0009] Preferably, the intermediate space is accessible or open from a direction extending from the outlet opening to the inlet opening. In other words, the end of the spinning cone facing the second end face is spaced from the outer surface of the channel body such that the outer intermediate space enclosed by the spinning cone can communicate with the surroundings of the spinning cone. This allows a stabilizing element suitable for stabilizing the position of the yarn-forming element to engage in the intermediate space.

[0010] According to a further preferred embodiment of the present invention, the channel body projects beyond the spinning cone in the direction of the second end face. Consequently, the channel body has an extension length along the passage such that the second end face or the outlet opening projects toward the end of the spinning cone facing this second end face or the outlet opening, forming a gap. This enables the end segment of the channel body having the outlet opening to be received by a cover element that defines the end of the spinneret and seals it off, thereby reliably discharging the thread from the spinneret. The channel body can be aligned with an outer surface of the cover element with respect to its extension length or spaced apart therefrom as required.

[0011] The cylindrical sub-segment preferably has a first sub-segment and a second sub-segment, wherein an outer diameter of the first sub-segment differs from an outer diameter of the second sub-segment. Further preferably, the first sub-segment and the second sub-segment are connected to one another via a stepped increase in their outer diameters. In other words, the outer surface sides of the first and second sub-segments merge into one another in a stepped manner. This allows a stop acting along the passage for a fastening element engaging the yarn-forming element on the outside to be provided in order to reliably position the yarn-forming element within the spinneret in the passage direction.

[0012] Particularly preferably, the first sub-segment is arranged along the channel body closer to the cone tip than the second sub-segment, wherein the outer diameter of the second sub-segment is larger than the outer diameter of the first sub-segment. As a result, the section of the second sub-segment radially projecting beyond the first sub-segment provides a stop, as described above, on a side of the second sub-segment facing the inlet opening, as well as a further stop on a side of the second sub-segment facing the outlet opening, via which the second sub-segment and thus the yarn-forming element can be clamped or locked in position via clamping or fastening means of the spinneret. This allows simple and secure assembly of the yarn-forming element within the spinneret.

[0013] According to a further preferred embodiment of the present invention, the cylindrical sub-segment comprises a first sub-segment and a second sub-segment, wherein an inner diameter of the first sub-segment is equal to an inner diameter of the second sub-segment. The cylindrical sub-segment is formed with its inner surface side equidistant from the outer surface side of the channel body over its extension length extending along the channel body. This allows for a deeper engagement for engagement elements of the spinneret in order to achieve a more stable positioning of the yarn-forming element within the spinneret.

[0014] According to a further preferred embodiment of the present invention, the yarn-forming element has a three-segmented passage. The passage preferably comprises at least three segments, each with a different inner diameter, wherein two consecutive segments merge seamlessly into one another with the interposition of a transition region. The transition region thus connects a segment of the passage with a diameter that is different from a diameter of the segment following along the passage.

[0015] Such transition regions promote fluid flows within the passage. Particularly preferably, a first passage segment, which adjoins the inlet opening, has the smallest inner diameter, and a third passage segment, which adjoins the outlet opening, has the largest inner diameter. An intermediate second passage segment comprises an inner diameter that is larger than the inner diameter of the first passage segment, but smaller than the inner diameter of the third inner diameter. The passage consequently widens from the inlet opening to the outlet opening. This allows the thread to be reliably introduced and discharged to the inlet opening and via this into the vortex chamber of the spinneret, particularly with regard to a piecing process in which the thread for piecing is preferably introduced into the yarn forming element via the outlet opening.

[0016] Although the yarn-forming element can be made of any material, according to the invention the yarn-forming element is formed from a single piece, which allows for particularly good guidance of the fibers or thread and a surface that is particularly free of separations and joints or seamlessly to be designed in a simple manner. For example, the yarn-forming element can be formed using an additive manufacturing process, which reliably prevents separations and joints. Possible additive manufacturing processes can include, for example, 3D printing, selective laser melting (SLM), electron beam melting (EBM), binder jetting (BJ) and / or fused deposition modeling (FDM). Additionally, subsequently or alternatively, the workpiece can also be sintered, particularly if the yarn-forming element is to be formed entirely from a ceramic material.Alternatively or additionally, the stereolithography process (SLA) can be used to form the yarn formation element from the ceramic material.

[0017] Furthermore, the yarn-forming element can preferably have a ceramic coating on at least all fiber-guiding surface sections in order to provide a particularly smooth, stable, and also resistant surface. Particularly preferably, at least the outer surface of the spinning cone and / or the inner surface of the passage have a ceramic coating.

[0018] According to a further preferred embodiment, the yarn-forming element is formed rotationally symmetrically and / or mirror-symmetrically to a central longitudinal axis of the passage. The latter configuration is particularly preferred when the channel body is not to be formed rotationally symmetrically. The symmetrical configuration of the yarn-forming element in any case facilitates its manufacture.

[0019] According to a further aspect of the present invention, an air spinneret is proposed which has a yarn forming element as described above.

[0020] Further features and advantages of the invention will become apparent from the following description of a preferred embodiment, with reference to the figures and drawings, which illustrate details essential to the invention, and from the patent claims. The individual features can be implemented individually or in combination in a preferred embodiment of the invention.

[0021] The invention is explained in more detail below with reference to an embodiment shown in the drawings. Fig. 1 is a schematic side view of a yarn forming element according to an embodiment, and Fig. 2 is a schematic sectional view of the Figure 1 shown yarn forming element along the cutting line AA.

[0022] Figures 1 and 2show a schematic side and sectional view of a yarn forming element 1 formed from a single piece of a ceramic material according to an embodiment of the present invention.

[0023] The yarn-forming element 1 comprises a spinning cone 2 with a cone tip 3, which forms a first end face 4 with an inlet opening 5 for the yarn-forming element 1. The yarn-forming element 1 further comprises a channel body 6, which forms a second end face 7 with an outlet opening 8 for the yarn-forming element 1. Due to the one-piece design of the yarn-forming element 1, the channel body 6 seamlessly transitions into the spinning cone 2.

[0024] The channel body 6 and the spinning cone 2 are passed through a passage 9, via which the inlet opening 5 and the outlet opening 8 are communicatively connected to one another for the passage of a thread. The passage 9 is divided into three segments 18, 19, 20, each with a different inner diameter, with two consecutive segments 18, 19, 20 merging seamlessly or without separation or connection points via a transition region 21, 22. A first passage segment 18, which adjoins the inlet opening 5, has the smallest inner diameter, and a third passage segment 20, which adjoins the outlet opening 8, has the largest inner diameter.An intermediate second passage segment 19, enclosed by a first 21 and a second transition region 22, via which the first 18 and second passage segments 20 are connected, comprises an inner diameter that is larger than the inner diameter of the first passage segment 18, but smaller than the inner diameter of the third inner diameter 20. The passage 9 consequently widens from the inlet opening 5 to the outlet opening 8.

[0025] The spinning cone 2 has a truncated cone-shaped sub-segment 10, which extends in the direction of the second end face 7 with increasing distance between its inner surface 11 and an outer surface 12 of the channel body 6 radially delimiting the passage 9, forming an intermediate space 13. Adjoining the truncated cone-shaped sub-segment 10 is a cylindrical sub-segment 14 assigned to the spinning cone 2, into which sub-segment the truncated cone-shaped sub-segment 10 merges seamlessly, i.e., without separation or connection points, on its side facing away from the cone tip 3 due to the one-piece design of the yarn-forming element 1. The cylindrical sub-segment 14 comprises a first sub-segment 16 and a second sub-segment 17, wherein an inner diameter of the first sub-segment 16 is equal to an inner diameter of the second sub-segment 17. The outer diameter of the first sub-segment 16, however, is smaller than the outer diameter of the second sub-segment 17.The second sub-segment 17 is therefore formed with a greater material thickness than the first sub-segment 16. The first sub-segment 16 and second sub-segment 17 merge into one another in a stepped manner on the outside, forming a stop pointing both toward the inlet opening 5 and toward the outlet opening 8.

[0026] The intermediate space 13 delimited on the outside by the truncated cone-shaped sub-segment 10 and the cylindrical sub-segment 14 is accessible from a direction running from the outlet opening 8 to the inlet opening 5, wherein the channel body 6 projects beyond the spinning cone 2 in the direction of the second end face 7 or the outlet opening 8.

[0027] The yarn forming element 1 is rotationally symmetrical with respect to a central longitudinal axis M of the passage 9.

[0028] The yarn-forming element 1 is suitable for an air-jet spinneret, by means of which an air-spun thread can be produced. The air-jet spinneret has appropriate fastening means for receiving the yarn-forming element 1 in order to be able to position the yarn-forming element 1 precisely and as required opposite a fiber sliver feed with the conical tip 3. For this purpose, the air-jet spinneret, according to an embodiment not shown, can comprise engagement elements which come into contact with the radially outer surface of the first sub-segment 16 as well as with the stop and with the surface of the second sub-segment 17 facing the outlet opening 8. This enables reliable and stable positioning of the yarn-forming element 1 within the air-jet spinneret, which also allows effortless replacement of the yarn-forming element 1. List of reference symbols

[0029] 1 Yarn formation element 2 Spinning cone 3 Cone tip 4 First end face 5 Inlet opening 6 Channel body 7 Second end face 8 Outlet opening 9 Passage 10 Truncated cone-shaped sub-segment 11 Inner surface side of the truncated cone-shaped sub-segment 12 Outer surface side of the channel body 13 Intermediate space 14 Cylindrical sub-segment 15 Inner surface side of the cylindrical sub-segment 16 First sub-segment 17 Second sub-segment 18 First segment 19 Second segment 20 Third segment 21 First transition area 22 Second transition area MCenter longitudinal axis of the passage

Claims

1. A yarn forming element (1) for an air spinning nozzle, comprising a spinning cone (2) having a cone tip (3), the spinning cone (2) forming a first end face (4) having an inlet opening (5), a channel body (6) forming a second end face (7) having an outlet opening (8), the channel body (6) and the spinning cone (2) being interconnected, and a passage (9), which passes through the channel body (6) and the spinning cone (2) in order to connect the inlet opening (5) to the outlet opening (8), wherein the spinning cone (2) has a frustoconical partial segment (10), which extends toward the second end face (7) with increasing distance of the inner surface side (11) of said frustoconical partial segment (10) from an outer surface side (12) of the channel body (6) such that an intermediate space (13) is formed, which channel body (6) radially delimits the passage (9), characterised in that the yarn forming element (1) is formed as a single piece, more particularly from a ceramic material.

2. The yarn forming element (1) according to claim 1, characterised in that the spinning cone (2) has a cylindrical partial segment (14), into which the frustoconical partial segment (10) transitions on its side facing away from the cone tip (3), and an inner surface side (15) of the cylindrical partial segment (14) is spaced apart from the outer surface side (12) of the channel body (6) such that the intermediate space (13) formed is continued.

3. The yarn forming element (1) according to claim 1 or 2, characterised in that the intermediate space (13) is accessible from a direction running from the outlet opening (8) to the inlet opening (5).

4. The yarn forming element (1) according to at least one of the preceding claims, characterised in that channel body (6) protrudes beyond the spinning cone (2) toward the second end face (7).

5. The yarn forming element (1) according to at least one of the preceding claims, characterised in that the cylindrical partial segment (14) has a first partial segment (16) and a second partial segment (17), and the inner diameter of the first partial segment (16) is equal to the inner diameter of the second partial segment (17).

6. The yarn forming element (1) according to at least one of the preceding claims 1 to 4, characterised in that the cylindrical partial segment (14) has a first partial segment (16) and a second partial segment (17), and the outer diameter of the first partial segment (16) is different from the outer diameter of the second partial segment (17).

7. The yarn forming element (1) according to claim 6, characterised in that first partial segment (16) is arranged closer to the cone tip (3), along the channel body (6), than the second partial segment (17) is, and the outer diameter of the second partial segment (17) is greater than the outer diameter of the first partial segment (16).

8. A yarn forming element (1) according to claim 6 or 7, characterised in that the inner diameter of the first partial segment (16) is equal to the inner diameter of the second partial segment (17).

9. The yarn forming element (1) according to at least one of the preceding claims, characterised in that the passage (9) has at least three segments (18, 19, 20) having different respective inner diameters, and each pair of consecutive segments (18, 19, 20) has a seamless transition by means of an interposed transition area (21, 22).

10. The yarn forming element (1) according to one of the preceding claims, characterised in that the yarn forming element (1) has a ceramic coating at least on all fibre-guiding surface portions.

11. The yarn forming element (1) according to at least one of the preceding claims, characterised in that the yarn forming element (1) is rotationally symmetric and / or mirror symmetric with respect to the central longitudinal axis (M) of the passage (9).

12. An air spinning nozzle for an air-spinning device of an air-spinning machine, characterised by a yarn forming element (1) according to at least one of the preceding claims.

13. A method for producing a yarn forming element (1), characterised in that the yarn forming element (1) is a yarn forming element (1) according to any one of claims 1 to 11, wherein the yarn forming element (1) is formed as a single piece, more particularly from ceramic, more particularly by means of a sintering process or a stereolithography method.

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