EP3371352B1 - Thread draw-off nozzle - Google Patents

Description

The present invention relates to a yarn withdrawal nozzle for an open-end rotor spinning device having an end face, a nozzle bore and a funnel-shaped Garnumlenkfläche connecting the end face and the nozzle bore, wherein the end face connects to the Garnumlenkfläche and wherein the end face and the Garnumlenkfläche form an effective diameter of the thread take-off.

Thread withdrawal nozzles have become known in the prior art in open-end rotor spinning devices in many designs. Such thread take-off nozzles have the task of redirecting the spun yarn during removal from the spinning device and to give the withdrawn yarn a false twist. The true twist of the yarn is introduced predominantly between the yarn draw-off nozzle and the draw-off device in the freshly spun yarn, but does not propagate sufficiently into the rotor groove. For a good spinning stability, however, it is necessary to achieve the highest possible yarn twist also in the area of the rotor groove. The yarn draw-off nozzle must thus enable the reproduction of the genuine yarn twist into the rotor groove on the one hand and on the other hand give the yarn as much as possible an additional false twist. The false twist and thus the spinning stability is greater, the greater the radius of the Garnumlenkfläche. Due to the crank-like circulation of the yarn on the yarn draw-off nozzle, there is also a comparatively high temperature stress on both the drawn yarn and the take-off nozzles. The design of the thread take-off nozzle is thus essential.

From the DE 32 39 289 C2 is a thread take-off nozzle with a shortened Garnberührungsbahn known. The shortening of the Garnberührungsbahn is achieved in that the upper part of the yarn draw-off, in which Usually the funnel-shaped Garnumlenkfläche merges into the tangentially adjoining end face is cut off. Thus, there is a pronounced, circumferential edge at the transition between the Garnumlenkfläche and the flat end face. The withdrawal force, which acts on the spun thread, should be reduced and thread breaks should be avoided.

The DE 199 01 147 B4 On the other hand, such an edge is disadvantageous, since a high surface pressure is generated during the crank-like rotation of the thread over this edge. To avoid overheating damage to the thread take-off nozzle, suggests the DE 199 01 147 B4 to form the Garnumlenkfläche with a maximum radius of curvature of 3 mm. At the Garnumlenkfläche the end face should connect tangentially and form a yarn supporting the guide surface, which is considered advantageous.

The object of the present invention is to propose a yarn draw-off nozzle which avoids overheating of the draw-off nozzle and enables a good propagation of the yarn twist into the rotor groove.

The object is achieved with the features of claim 1.

A yarn withdrawal nozzle for an open-end rotor spinning device has an end face, a nozzle bore and a funnel-shaped yarn deflection surface connecting the end face and the nozzle bore. The end face adjoins the Garnumlenkfläche, wherein the end face and the Garnumlenkfläche form an effective diameter of the thread take-off. The end face and the Garnumlenkfläche thereby form an input-side region of the yarn draw-off nozzle, while the nozzle bore forms an output-side region of the yarn draw-off nozzle. The nozzle bore usually has a constant inner cross section over the length or the axial extent of the yarn draw-off nozzle, while the yarn deflection surface reduces over the axial extent of the yarn draw-off nozzle Internal cross section has. The end face is oriented substantially radially to the nozzle bore, but may also have a curved or radially outwardly conically sloping course.

It is known from the prior art that with a small radius of curvature of the Garnumlenkfläche the Garnumlenkfläche be shortened and thereby the unwanted heat development can be reduced. However, this improvement in heat development is offset by a reduction in the introduced false twist, which in turn prevents rotation propagation into the rotor groove. The shortening of the Garnumlenkfläche is thus usually accompanied by a deterioration of the spinning stability.

It is now envisaged that the effective diameter of the yarn withdrawal nozzle is less than 8 mm and the Garnumlenkfläche has a radius of curvature of less than 2.5 mm. The present invention has found that in addition to the actual Garnumlenkfläche and the end face has a significant influence on the rotation propagation. In the present yarn withdrawal nozzle not only the radius of the Garnumlenkfläche, but at the same time the entire end face is substantially reduced, so that the overall result is a very small effective diameter. The combination of a small radius of Garnumlenkfläche with the small effective diameter or the smaller end face causes a change in the ratio of false rotations to actual rotations, so that much more real rotations arrive in the rotor groove. Despite the fact that there is less false twist, the overall rotation of the thread towards the rotor groove can thus be increased and thus a very good spinning stability can be achieved. At the same time the heat development is reduced by the short Garnumlenkfläche and subtracted the thread gentler.

According to an advantageous development of the invention, a head diameter of the yarn draw-off nozzle is less than 10 mm. The head diameter is defined as the largest outer diameter of the yarn withdrawal nozzle. Under certain circumstances, the head diameter can also be equal to the effective diameter; As a rule, however, the head diameter is slightly larger than the effective diameter, so that radially outward adjoins the end face another, annular surface, which, however, is not usually in contact with the thread. Due to the very small outer diameter of the yarn withdrawal nozzle, the frictional heat generated by the circled over the yarn withdrawal nozzle thread, are dissipated much better, since the heat radiation of the part of the rotor housing in which the yarn take-off is stored, is not hindered by the Fadenabzugsdüse.

It is also advantageous if the Garnumlenkfläche tangentially adjoins the end face. Thus, no edges are arranged between the Garnumlenkfläche and the end face. The propagation of the true yarn twist in the rotor groove is thereby further improved. At the same time, the contact force of the thread is reduced at the transition from the end face to Garnumlenkfläche, so that less friction occurs and thus the temperature stress of the thread is reduced. It is also advantageous if the Garnumlenkfläche tangentially connects to the nozzle bore.

In order additionally to introduce a spinning stability further increasing rotation in the thread, it is advantageous if the Garnumlenkfläche macrostructures, in particular radially arranged notches having. These stimulate the thread in a manner known per se to rotate about its longitudinal axis and thereby bring a false twist into the thread in a comparatively thread-saving manner.

It is advantageous for the rotation propagation into the rotor groove, if the notches have a radially outer notch inlet and a radially inner notch outlet and the notch outlet is arranged in an input region of the nozzle bore. The notch thus extends into the nozzle bore into it and is characterized comparatively steep. The thread can run better in the notches and thus experiences a particularly significant change in length in the circumferential yarn leg. The change in length and therefore also the thread tension tip produced by the notch are greater, the steeper the notch. Due to the steeper outlet of the notches in the nozzle bore while a smoother transition when reaching and leaving the notch is achieved at the same time, so that negative influences of the notches on the yarn quality can be avoided.

It is advantageous in this case if the notch outlet is arranged at a depth of between 0.1 mm and 0.5 mm away from an inlet of the nozzle bore. With such an arrangement of the notch spout, the thread can be guided particularly securely into the notches and a steep notch is achieved.

In addition, it is advantageous if the notches have a flatter inlet wall and a steeper baffle wall. The thread is thereby safely passed over the inlet wall to the notch base. Skipping the notches through the thread can thereby be avoided.

For this reason, it is also particularly advantageous if between the inlet wall of the notch and the baffle wall, a preferably flat, scored groove bottom is arranged. The inlet wall and the baffle wall thus do not abut each other directly in the region of the notch base, which was often rounded in the prior art. The run-in over the inlet wall thread therefore runs defined along the notch and is safely guided to the notch bottom. In contrast, it was still usual in V-shaped notches despite gently descending inlet wall that the thread does not reach the notch bottom, but jumps from the inlet wall directly onto the baffle.

Preferably, the notch bottom has a width between 0.16 mm and 0.22 mm, in particular between 0.18 mm and 0.20 mm. The thread can be braked gently as it passes over the notch bottom and slide in the direction of the baffle. The yarn is thus safely and over a longer period of the effect of the notch exposed, at the same time the yarn damaging effect of the notches is reduced. It has been found that, with such a width of the notch bottom, an optimal compromise can be achieved between the spinnability enhancing effect of the notches on the one hand and the yarn quality on the other hand.

It is also advantageous if the inlet wall and / or the baffle wall as flat surfaces, d. H. uncoiled, are formed. Preferably, the notch bottom between the baffle wall and the inlet wall is formed as a flat surface. The thread is thereby defined defined within the notch over its entire length and the production of the thread take-off nozzle is facilitated.

If the inlet wall and / or the baffle wall are bent and / or bent, then a gentler thread treatment can take place in this way than in the case of an uncurved surface. The kinked or curved surface shortens the steep surface and continues through a flatter surface to the top of the nozzle.

According to a further advantageous embodiment of the yarn withdrawal nozzle is an angle of the baffle to a notch center plane between 32.5 ° and 47.5 °, preferably between 35 ° and 45 °, more preferably between 37 ° and 42 °. The release of the thread after its deceleration by the baffle can thus also be gentle and an undefined jumping of the thread can also be avoided. For the safe guidance of the thread to the notch base or notch bottom, it is also advantageous if the angle of the inlet wall to a notch center plane between 50 ° and 65 °, preferably between 52 ° and 60 °, more preferably between 54 ° and 58 °.

In the case of a bent or curved inlet wall and / or the baffle wall, it is advantageous if a first angle (β ₁ ) of a first part of the inlet wall and / or the baffle wall to a notch central plane between 32.5 ° and 47.5 °, preferably between 35 ° and 45 °, more preferably between 37 ° and 42 ° and a second angle (β2) of a second part of the inlet wall (8) and / or the baffle (9) to the first part between 10 ° and 20 °, preferably between 13 ° and 17 °. Hereby, the thread is performed very gently.

For achieving a good yarn quality, it is also advantageous if the Garnumlenkfläche in the region of the notch enemas a circumferential recess, in particular a circumferential, preferably rounded, groove. The recess can be directly adjacent to the notch enemas; it is likewise possible for an upper region of the notches with the original notch inlets to be removed through the cutout, and thus for new notches occurring at the transition of the cutout to the notch to be found in a deeper area of the funnel-shaped yarn deflection surface. The recess itself can reach up to the end face of the thread withdrawal nozzle or even interrupt the Garnumlenkfläche only. By such a recess, an aggressive effect of the notch run on the thread can be further reduced. Instead of a circumferential groove, it is also possible to form the recess, for example by a spherical recess.

In order to safely release the thread after braking, the depth of the notch is preferably between 0.14 mm and 0.25 mm, preferably between 0.16 mm and 0.22 mm and particularly preferably between 0.16 and 0.20 mm ,

Figur 1

eine schematische Darstellung einer Offenendspinnvorrichtung mit einem Spinnrotor und einer Abzugsdüse,

Figur 2

eine schematische Darstellung einer Fadenabzugsdüse mit einem verkleinerten Wirkdurchmesser,

Figur 3

eine schematische Schnittdarstellung einer Fadenabzugsdüse mit einem verkleinerten Wirkdurchmesser und mit Kerben,

Figur 4

eine schematische Schnittdarstellung einer Kerbe einer Fadenabzugsdüse,

Figur 5

eine schematische Schnittdarstellung einer weiteren Fadenabzugsdüse mit einer umlaufenden Ausnehmung,

Figur 6

eine weitere Ausführung einer Fadenabzugsdüse mit einer umlaufenden Ausnehmung sowie

Figur 7

eine weitere Ausführung einer Fadenabzugsdüse mit einer geknickten Prallwand.

Further advantages of the invention will be described with reference to the embodiments illustrated below. Show it:

FIG. 1

a schematic representation of an open-end spinning device with a spinning rotor and a discharge nozzle,

FIG. 2

a schematic representation of a thread take-off nozzle with a reduced effective diameter,

FIG. 3

a schematic sectional view of a yarn withdrawal nozzle with a reduced effective diameter and notches,

FIG. 4

a schematic sectional view of a notch of a thread take-off nozzle,

FIG. 5

a schematic sectional view of another yarn withdrawal nozzle with a circumferential recess,

FIG. 6

a further embodiment of a yarn withdrawal nozzle with a circumferential recess and

FIG. 7

another embodiment of a yarn withdrawal nozzle with a kinked baffle.

FIG. 1 shows a schematic sectional view of a spinning rotor 2 and a yarn draw-off nozzle 1 in an open-end spinning device only partially shown here. To produce a yarn F, the spinning rotor 2 is supplied in a known manner with a fiber material dissolved in individual fibers. The spinning rotor 2 runs during the yarn production at high speeds, so that the supplied fibers are stored in the form of a fiber ring in the rotor groove 3 of the spinning rotor 2. The newly spun yarn F is withdrawn continuously via the yarn draw-off nozzle 1 and reaches Due to the rotation of the spinning rotor 2 thus creates a crank-like circumferential yarn leg 4, in which the stored in the rotor groove 3 fibers are involved. The yarn draw-off nozzle 1 is mounted in a manner known per se either in an extension or in an insert of a cover element of the rotor housing 17.

The yarn withdrawal nozzle 1 has in the usual way a cylindrical nozzle bore 6 and a curved Garnumlenkfläche 5 for the withdrawn thread F on. Finally, on the yarn deflection surface 5, on the side of the yarn withdrawal nozzle 1 facing away from the nozzle bore 6, there is an end face 16 of the yarn draw-off nozzle 1, which in different ways, for example flat, curved, or also in the direction of the outer diameter of the yarn draw-off nozzle 1, here with head diameter D. _K is designated, may be formed sloping. The curved Garnumlenkfläche 5 and the end face 16 together form a standing with the thread F in contact effective diameter Dw of the yarn draw 1. The nozzle bore 6 is generally coaxial with the axis of rotation 15 of the spinning rotor 2, so that the withdrawn thread F is deflected during its withdrawal from the rotor groove 3 on the Garnumlenkfläche 5 by about 90 °. As described above, it is desirable that the rotation introduced into the thread propagate as far as possible into the rotor groove 3 in order to achieve the best possible spinning stability.

FIG. 2 shows in a schematic sectional view of a yarn draw-off nozzle 1, which has a Garnumlenkfläche 5 with a very small radius of curvature R of less than 2.5 mm and a reduced effective diameter D _W of less than 8 mm. Thus, in the present yarn withdrawal nozzle and the annular end face 16 is greatly reduced. While an excessive reduction of the radius of curvature R was always avoided in conventional yarn withdrawal nozzles, since this was associated with a reduction in spinning stability, has now been surprising Nevertheless, a good spinning stability can be achieved if at the same time the end face 16 or the entire effective diameter D _{W is} reduced. The reason for this is that due to the special, overall small dimensions less false twist is introduced into the thread F, but at the same time the propagation of the true rotation is improved in the rotor groove 3 at otherwise identical spinning ratios. It can thus be increased with the same geometry of the spinning rotor 2 alone by the use of the yarn draw-off nozzle 1 described without changes in the rotor speed or the delivery speed, the total rotation of the thread F to the rotor groove. At the same time, the yarn F is gently removed by the geometry of the yarn draw-off nozzle 1 with a very small effective diameter D _W. Due to the lower friction on the shortened Garnumlenkfläche 5 and end face 16 reduces the thread withdrawal tension and at the same time the temperature stress of the thread F.

At the same time, the yarn draw-off nozzle 1 shown here also has a particularly small head diameter D _K of less than 10 mm. Now, turn off Fig. 1 can be seen, this is a particular large radiating surface AF on which projecting into the spinning rotor 2 part of the rotor housing 17, here an extension of a cover member of the rotor housing achieved. The resulting at the yarn withdrawal 1, already reduced by the shortened Garnumlenkfläche 5 friction heat can thereby be dissipated even better. The thermal load of the yarn draw-off nozzle 1 itself can also be reduced thereby. At the same time damage to the withdrawn yarn F and yarn breaks are avoided by the reduced surface temperature at the yarn draw 1. This has a very beneficial effect especially on chemical fibers. Likewise, contamination of the yarn draw-off nozzle 1 are avoided especially in chemical fibers.

FIG. 3 shows a thread take-off nozzle 1, which is additionally provided with notches 7, in a sectional view. The notches 7 (present are two Notches 7 opposite each other recognizable) are arranged in the Garnumlenkfläche 5, but extend into the nozzle bore 6 into it. It has proved to be particularly advantageous if the notch run 11, which is defined here by the exit-side intersection or the exit-side intersection of the notch bottom 12 with the inner surface of the thread take-off 1, at a distance A between 0.1 mm and 0.5 mm is located away from the inlet of the nozzle bore. For example, the distance A is 0.25 mm. The entrance of the nozzle bore 6 is defined as the beginning of the constant inner cross section of the yarn withdrawal nozzle 1 and is characterized by the tangential edge between the Garnumlenkfläche 5 and the nozzle bore 6. The notch inlet 10 is in turn defined in the case of conventional V-shaped notches by the common intersection of the inlet wall 8 and the baffle 9 with the inner surface of the nozzle funnel 5 or in the present case by the input-side cutting line of the notch bottom 12 with the inner surface of the nozzle funnel.

FIG. 4 shows a schematic section through a notch 7 of a yarn draw-off nozzle 1, with which a particularly good and safe effect of the notch 7 on the withdrawn yarn F can be ensured. The notch 7 has in a conventional manner an inlet wall 8 and a baffle 9, which reaches the thread F during its crank-shaped circulation over the Garnumlenkfläche 5 successively. The direction of rotation of the thread F is symbolized here by an arrow. In contrast to known notch shapes, which were always executed V-shaped, it is now provided that the inlet wall 8 and the baffle 9 do not directly adjoin one another, but a defined, preferably flat, notched bottom 12 with a defined width B between the inlet wall 8 and the baffle 9 extends. By the notch bottom 12 between the inlet wall 8 and the baffle 9 ensures that the thread F reaches the notch base or the flat notch bottom 12 in each case and thus the notch 7 can exert its effect on the thread F. An undefined Jumping of the thread F from the inlet wall 8 directly on the baffle 9 can be avoided thereby.

The secure reaching of the notch bottom 12 is still supported according to the present illustration in that the thread F is passed over a comparatively flat inlet wall 8 slowly and gently in the direction of the notch bottom 12. The angle α to a notch center plane 14 or to a parallel thereto is preferably between 54 ° and 58 ° and is designed for example at 56 °. The notch bottom 12 further has a width B between 0.18 mm and 0.24 mm. For example, the width B of the notch bottom is 0.22 mm. The angle β of the baffle 9 to the notch center plane 14, however, is preferably between 37 ° and 42 °. According to a particularly advantageous embodiment, the angle β is 40 °. This results in a notch angle α + β between the inlet wall 8 and the baffle 9, for example, 96 °. It has also proved to be advantageous for the guidance of the thread F along the notch 7 when the depth T of the notch 7 is between 0.16 mm and 0.20 mm. The notch shape shown thus not only contributes to improving the spinning stability, but also to improving the yarn quality.

FIG. 5 shows a further embodiment of a yarn draw-off nozzle 1, in which the yarn damaging effect of the notch inlet 10 by a peripheral recess 13, here a circumferential groove, is defused. The comparatively sharp transition between the curved Garnumlenkfläche 5 and the notch 7 can thereby be made gentler. The circumferential groove preferably has a radius of between 0.15 mm and 0.3 mm and in the present case extends as far as the end face. However, the groove could also be designed such that it only interrupts the Garnumlenkfläche 5.

FIG. 6 shows another embodiment of a yarn withdrawal nozzle 1, in which the notch enemas 10 was defused by a spherical recess 13. The radius of the spherical recess 13b is preferably on the inner diameter D _{I of} the nozzle bore 6 and is between 0.7 * D _I and 0.9 * D _I. For example, the radius R _{2 is} 0.8 * D _I. The aggressive, yarn damaging effect of the notch enemas 10 can thereby be substantially reduced.

In FIG. 7 a notch 7 is shown, in which the baffle 9 is formed kinked. The notch bottom 12 facing first part of the baffle 9 is inclined at an angle β ₁ to the notch center plane 14. The edge of the yarn withdrawal nozzle 1 facing second part of the baffle 9 is formed flat and has a second angle β ₂ . With this type of notch 7, a gentler thread treatment is possible than with the notches shown above. because the baffle 9 does not slow down the thread as much. Such a kinked training is also possible for the inlet wall 8 in addition to or as an alternative to the kinked baffle 9.

It has been found that the small radius of curvature in combination with the small effective diameter D _{W is} particularly advantageous in the case of a yarn withdrawal nozzle 1 provided with notches 7, since in addition to increasing the true twist, a false twist is also introduced into the yarn F. The spinning stability is thereby further improved.

LIST OF REFERENCE NUMBERS

1

off nozzle

2

spinning rotor

3

rotor groove

4

circumferential yarn leg

5

Garnumlenkfläche

6

nozzle bore

7

score

8th

entry wall

9

baffle wall

10

notched inlet

11

notch outlet

12

Kerbboden

13

recess

14

Notch midplane

15

Rotary axis of the spinning rotor

16

face

17

rotor housing

B

Width of the notch bottom

T

Depth of notch

F

thread

D _K

Head diameter

D _I

Inner diameter of the nozzle bore

D _W

Effective diameter

A

Distance of the notch outlet from the inlet of the nozzle bore

α

Angle of the inlet wall

β

Angle of the baffle

R

Radius of curvature of Garnumlenkfläche

AF

radiating

Claims (13)

1. Thread draw-off nozzle (1) for an open-end rotor spinning device with a front surface (16), a nozzle bore (6) and a funnel-shaped yarn deflection surface (5) connecting the front surface (16) and the nozzle bore (6), whereas the front surface (16) adjoins the yarn deflection surface (5) and whereas the front surface (16) and the yarn deflection surface (5) form an effective diameter (D_W) of the thread draw-off nozzle (1), characterized in that the effective diameter (D_W) of the thread draw-off nozzle (1) is less than 8 mm, and the yarn deflection surface (5) features a radius of curvature (R) of less than 2.5 mm.
2. Thread draw-off nozzle according to the preceding claim, characterized in that a head diameter (D_K) of the thread draw-off nozzle (1) is less than 10 mm.
3. Thread draw-off nozzle according to one of the preceding claims, characterized in that the yarn deflection surface (5) tangentially adjoins the front surface (16).
4. Thread draw-off nozzle according to one of the preceding claims, characterized in that the yarn deflection surface (5) features macrostructures, in particular notches (7) that are arranged in a radial manner.
5. Thread draw-off nozzle according to one of the preceding claims, characterized in that the notches (7) feature a radially outer notch inlet (10) and a radially inner notch outlet (11), and the notch outlet (11) is arranged in an entrance area of the nozzle bore (6).
6. Thread draw-off nozzle according to one of the two preceding claims, characterized in that the notches (7) feature a flatter inlet wall (8) and a steeper baffle wall (9).
7. Thread draw-off nozzle according to the preceding claim, characterized in that a notch bottom (12) is arranged between the inlet wall (8) and the baffle wall (9) whereas the notch bottom (12) preferably features a width (B) of between 0.16 mm and 0.22 mm, in particular between 0.18 mm and 0.20 mm.
8. Thread draw-off nozzle according to one of the two preceding claims, characterized in that an angle (β) of the baffle wall (9) to a center notch plane (14) is between 32.5° and 47.5°, preferably between 35° and 45°, more preferably between 37° and 42°.
9. Thread draw-off nozzle according to one of the preceding claims 6 to 7, characterized in that a first angle (β₁) of a first part of the inlet wall (8) and/or the baffle wall (9) to a center notch plane (14) is between 32.5° and 47.5°, preferably between 35° and 45°, more preferably between 37° and 42°, and a second angle (β₂) of a second part of the inlet wall (8) and/or the baffle wall (9) to the first part is between 10° and 20°, preferably between 13° and 17°.
10. Thread draw-off nozzle according to one of the preceding claims 5 to 9, characterized in that the yarn deflection surface (5) features, in the area of the notch inlets (10), a circumferential recess (13), in particular a circumferential, preferably rounded, groove.
11. Thread draw-off nozzle according to one of the preceding claims 6 to 10, characterized in that the inlet wall (8) and/or the baffle wall (9) are formed to be flat.
12. Thread draw-off nozzle according to one of the preceding claims 6 to 10, characterized in that the inlet wall (8) and/or the baffle wall (9) are formed to be kinked and/or bent.
13. Thread draw-off nozzle according to one of the preceding claims 4 to 12, characterized in that a depth (T) of the notch (7) is between 0.14 mm and 0.25 mm, preferably between 0.16 mm and 0.22 mm and more preferably between 0.16 and 0.20 mm.

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