Open-end spinning device with an intermediate chamber

Abstract

An open-end spinning device of a rotor spinning machine has a spinning rotor with a rotor cup, in which fiber material is spun, and with a rotor shaft through which the spinning rotor is driven. A bearing is arranged in a contactless way with a drive to drive the spinning rotor. A rotor housing is provided in which the rotor cup is arranged and which is impinged with spinning negative pressure (p.sub.SU) during spinning operation through a negative pressure channel. A drive housing is provided in which the rotor shaft of the spinning rotor extends, and in which the drive and the bearing of the spinning rotor are arranged. The rotor housing and the drive housing are arranged spaced apart from one another in the open-end spinning device in the axial direction of the rotor shaft. In a method to operate such an open-end spinning device, the rotor housing is impinged with spinning negative pressure (p.sub.SU) during the spinning operation. Air current is prevented from flowing from the rotor housing into the drive housing by arranging the rotor housing and the drive housing spaced apart from one another in the axial direction of the rotor shaft.

Claims

1. An open-end spinning device of a rotor spinning machine, comprising: a spinning rotor having a rotor cup in which fiber material is spun; a rotor shaft through which the spinning rotor is driven, the rotor shaft arranged in a bearing with an individual drive for driving the spinning rotor; a rotor housing in which the rotor cup is arranged, the rotor housing impinged with spinning negative pressure (pSU) through a negative pressure channel; a drive housing in which the rotor shaft extends and in which the drive and bearing of the spinning rotor are arranged; the rotor housing and the drive housing spaced apart from one another in an axial direction of the rotor shaft; an intermediate chamber enclosed by walls and arranged between the rotor housing and the drive housing, the intermediate chamber having a first connecting opening to the rotor housing and a second connecting opening to the drive housing; and the intermediate chamber having a third opening through which the intermediate chamber is connected to a negative pressure source when spinning operation of the open-end spinning device is interrupted.

2. The open-end spinning device according to claim 1, wherein the first connecting opening and the second connecting opening are defined as a ring gap within the walls around the rotor shaft or around an axially extending collar of the rotor cup.

3. The open-end spinning device according to claim 1, wherein the bearing comprises an axial bearing acting on an end of the spinning rotor facing away from the rotor cup.

4. The open-end spinning device according to claim 3, wherein the axial bearing comprises an axial air bearing.

5. The open-end spinning device according to claim 3, wherein the bearing comprises a magnetic bearing.

6. An open-end spinning device of a rotor spinning machine, comprising: a spinning rotor having a rotor cup in which fiber material is spun; a rotor shaft through which the spinning rotor is driven, the rotor shaft arranged in a bearing with an individual drive for driving the spinning rotor; a rotor housing in which the rotor cup is arranged, the rotor housing impinged with spinning negative pressure (pSU) through a negative pressure channel; a drive housing in which the rotor shaft extends and in which the drive and bearing of the spinning rotor are arranged; the rotor housing and the drive housing spaced apart from one another in an axial direction of the rotor shaft; an intermediate chamber arranged between the rotor housing and the drive housing, the intermediate chamber having a first connecting opening to the rotor housing and a second connecting opening to the drive housing; the intermediate chamber having a third opening through which the intermediate chamber is connected to a negative pressure source when spinning operation of the open-end spinning device is interrupted; and wherein the intermediate chamber is connected to the negative pressure channel for the spinning negative pressure (pSU) or to an own negative pressure channel through the third opening.

7. The open-end spinning device according to claim 1, wherein at least one of the third opening or the rotor housing is configured with a controllable shut-off device that is activated by opening and closing the rotor housing.

8. The open-end spinning device according to claim 1, wherein the third opening is provided with an air filter.

9. A method to operate an open-end spinning device of a rotor spinning machine wherein the open-end spinning device includes: a spinning rotor driven by an individual drive; a spinning rotor arranged in a contactless way in a bearing, the spinning rotor including a rotor cup and with a rotor shaft; the rotor cup arranged in a rotor housing impinged with spinning negative pressure (pSU) during spinning operation; the rotor shaft extending into a drive housing in which the drive and the bearing of the spinning rotor are arranged; wherein the method further comprises: preventing an air current from the rotor housing to the drive housing by spacing the rotor housing and the drive housing from each other in axial direction of the rotor shaft; enclosing an intermediate chamber with walls between the rotor housing and the drive housing; defining a first connecting opening from the intermediate chamber to the rotor housing around the rotor shaft, and a second connecting opening from the intermediate chamber to the drive housing around the rotor shaft; and impinging the intermediate chamber with negative pressure when the spinning operation is interrupted and the rotor housing is opened such that an air current is prevented from entering the drive housing.

10. The method according to claim 9, wherein the intermediate chamber is impinged with negative pressure when the rotor housing is opened through a negative pressure channel for the spinning negative pressure (pSU) or through an own negative pressure channel.

11. The method according to claim 9, wherein the bearing of the spinning rotor comprises an axial air bearing, and further comprising controlling air flowing through the air bearing such that air pressure (pAG) in the drive housing is always greater than the air pressure (pZK) in the intermediate chamber.

12. A method to operate an open-end spinning device of a rotor spinning machine wherein the open-end spinning device includes: a spinning rotor driven by an individual drive; a spinning rotor arranged in a contactless way in a bearing, the spinning rotor including a rotor cup and with a rotor shaft; the rotor cup arranged in a rotor housing impinged with spinning negative pressure (pSU) during spinning operation; the rotor shaft extending into a drive housing in which the drive and the bearing of the spinning rotor are arranged; wherein the method further comprises: preventing an air current from the rotor housing to the drive housing by spacing the rotor housing and the drive housing from each other in axial direction of the rotor shaft; arranging an intermediate chamber between the rotor housing and the drive housing; defining a first connecting opening from the intermediate chamber to the rotor housing around the rotor shaft, and a second connecting opening from the intermediate chamber to the drive housing around the rotor shaft; impinging the intermediate chamber with negative pressure when the spinning operation is interrupted and the rotor housing is opened such that an air current is prevented from entering the drive; and wherein the intermediate chamber is impinged with spinning negative pressure (pSU) through the negative pressure channel of the open-end spinning device or through an own negative pressure channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) More advantages of the invention are described by means of the embodiments described below, which show:

(2) FIG. 1 a side view of an open-end spinning device of a rotor spinning machine in a schematic overview;

(3) FIG. 2 a first embodiment of an open-end spinning device with an intermediate chamber connected to a negative pressure source;

(4) FIG. 3 a variation of the open-end spinning device shown in FIG. 2 with an intermediate chamber impinged with negative pressure;

(5) FIG. 4 a further variation of the open-end spinning device shown in FIG. 2 with an intermediate chamber impinged with negative pressure;

(6) FIG. 5 another embodiment of an open-end spinning device with an intermediate chamber impinged with negative pressure and an axial bearing comprising merely an axial magnetic bearing; and

(7) FIG. 6 an open-end spinning device with an intermediate chamber impinged with surrounding air.

DETAILED DESCRIPTION

(8) Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

(9) FIG. 1 shows a schematic side view of an open-end spinning device 1 of a rotor spinning machine 2. The rotor spinning machine 2 usually comprises a feeding device 8, which supplies fiber material 6 to the open-end spinning device 1 through an opening device 9 that opens the fiber material into individual fibers. In the open-end spinning device 1, the fiber material 6 is spun to yarn 7 in a rotor cup 4 (see FIGS. 2-6) of a spinning rotor 3, drawn off through a draw-off device 10 and wound on a bobbin 12 with a winding device 11.

(10) Apart from the spinning rotor 3 with the rotor cup 4 and rotor shaft 5 (see FIGS. 2-6), the open-end spinning device 1 comprises a rotor housing 15, in which the rotor cup 4 is arranged, and a drive housing 17, in which the shaft 5 of the spinning rotor 3 extends. According to this description, the spinning rotor 3 is driven by means of an individual drive 14 and arranged in a bearing 13. Here, support disk bearings, magnetic bearings and air bearings are considered as a bearing 13 of the spinning rotor. In this case, the bearing 13 comprises radial bearings 25 and can additionally also comprise an axial bearing 24 executed separately from the radial bearings 25. The axial bearing 24 can be executed as an axial air bearing 24a or as an axial magnetic bearing or also be formed by a combination of these two bearing types. Another type of bearing different from the bearing types shown can be used alternatively or additionally in the open-end spinning machines 1 of FIGS. 2-6. For reasons of clarity, only the bearing 13 is labeled without its individual components here.

(11) The rotor housing 15 is closed by means of a detachable lid 27, especially one that can be swiveled (see arrow). To perform maintenance work on the open-end spinning device, the lid 27 of the rotor housing 15 can be removed either by an automatic maintenance mechanism or an operator, as symbolized here by an arrow. According to this drawing, the lid 27 of the rotor housing 15 is connected to a swivel housing 29 that can be swiveled out and opened together with it. However, it is also possible to provide the rotor housing 15 with a separate lid 27. During the spinning operation, the rotor housing 15 is impinged with the spinning negative pressure p.sub.SU required for the spinning process by means of a negative pressure channel 16 of the open-end spinning device 1. To do this, the negative pressure channel 16 of the open-end spinning device 1 is connected here to a machine-long negative pressure line 33 which, in turn, is connected to a central negative pressure source 23. To maintain the spinning negative pressure p.sub.SU in the rotor housing 15, a seal 28 has been placed between the lid 27 of the rotor housing 15 and the rotor housing 15.

(12) On the other hand, the drive 14 and the bearing 13, which act together with the rotor shaft 5 of the spinning rotor 3, are arranged in a drive housing 17 separated from the rotor housing 15 in order to protect it from impurities coming from the surroundings and also from fiber fly and impurities coming from the spinning rotor 3 area. Thus, the rotor shaft 5 of the spinning rotor 3 extends from the rotor housing 15 to the drive housing 17.

(13) Owing to the high revolutions per minute of the spinning rotor 3, it is not possible to fully seal the rotor housing 15 from the drive housing 17. In conventional spinning devices, this also leads to the build-up of negative pressure in the drive housing 17 as well during the spinning operation, which then in turn causes air and impurities to be sucked into the drive housing 17 from the rotor housing 15 area when the rotor housing 15 is opened. To prevent this, according to FIG. 1, the rotor housing 15 and the drive housing 17 are arranged spaced-apart from one another in the axial direction of the rotor shaft 5 in the open-end spinning device 1. The drive housing 17 is now no longer directly connected to the rotor housing 15 but merely to an area of the open-end spinning device 1 not sealed from the surrounding air pressure p.sub.U. Thus, no negative pressure builds up in the drive housing 17 during the spinning operation, so that no impurities can be sucked any longer into the drive housing 17 even when the rotor housing 15 is opened. In this case, it is advantageous if the two housings 15 and 17 are separated from one another by at least 3 mm, preferably by at least 5 mm, very preferably by at least 10 mm, to securely prevent the effects that the negative pressure prevailing in the rotor housing 15 will have on the drive housing 17. According to an advantageous further development, an intermediate chamber 18 is provided between the rotor housing 15 and the drive housing 17 arranged at a distance from it. Such an open-end spinning device 1 with the rotor housing 15 and the drive housing 17 will be described in more detail below with the help of FIGS. 2-6, which show a detailed view of various embodiments of an open-end spinning device 1.

(14) FIG. 2 shows once again the rotor 3 with the rotor cup 4 and the rotor shaft 5. Furthermore, a draw-off nozzle 34 arranged in the lid 27 of the rotor housing 15 can be seen, through which the yarn 7 produced in the rotor cup 4 is drawn off. In the area of the drive housing 17, both the individual drive 14 and the bearing 13 can now be recognized in detail. In this case, two radial bearings 25 executed as magnetic bearings 25a are provided. Furthermore, an axial bearing 24 is provided that can comprise an axial magnetic bearing or an axial air bearing 24a or an axial bearing 24 combined from both types of bearing. Here, an axial air bearing 24a fed by a pressurized air source 31 is shown that acts on an end of the spinning rotor 3 facing away from the rotor cup 4.

(15) Furthermore, it can be seen in FIG. 2 that, in spite of the arrangement of ring seals 21, a ring gap remains in each case between the contiguous housings or chambers. To prevent air of the rotor housing 15 area from being sucked into the drive housing 17 when the rotor housing 15 is opened, an intermediate chamber 18 has therefore been arranged between the rotor housing 15 and the drive housing 17. The intermediate chamber 18 is connected to the rotor housing via a connecting opening 19 and to the drive housing 17 via a second connecting opening 20. To keep the size of the connecting openings 19 and 20 as small as possible, a ring seal 21 is provided in each case in the area of the two ring gaps.

(16) According to the embodiment of an open-end spinning device shown in FIG. 2, the intermediate chamber 18 has a third opening 22 that is in constant contact with a negative pressure source 23. For example, the intermediate chamber 18 can be in contact with the negative pressure source 23 for the spinning negative pressure p.sub.SU through the machine-long negative pressure line 33. Here, the intermediate chamber 18 is also connected to the negative pressure channel 16 for this.

(17) Thus, during the spinning operation, spinning negative pressure p.sub.SU prevails in the rotor housing 15, while a pressure P.sub.AG sets in inside the drive housing 17 owing to the axial bearing 24 executed as air bearing 24a that exceeds the spinning negative pressure p.sub.SU. However, due to the very small amount of air passing through the air bearing 24a compared to the amount of air passing through the negative pressure channel 16, the air pressure P.sub.AG always remains lower than the surrounding air pressure P.sub.U that surrounds the spinning device 1, even during the spinning operation. As a result of this, an air pressure P.sub.ZK sets in inside the intermediate chamber 18 that is also lower than the surrounding air pressure P.sub.U and lies between the spinning negative pressure P.sub.SU and the air pressure of the drive housing P.sub.AG. Thus, during the spinning operation, an air current is generated from the drive housing to the intermediate chamber that advantageously prevents impurities from penetrating the drive housing 17 already during the spinning operation.

(18) When the rotor housing 15 is opened, however, pressure is now equalized in the rotor housing 15 to that of the surrounding air pressure P.sub.U. Any impurities from the rotor housing 15 are now, however, merely sucked into the intermediate chamber 18 owing to the negative pressure P.sub.ZK adjacent to the intermediate chamber and transported out to the negative pressure channel 16 through the third opening 22. The penetration of impurities from the rotor housing 15 into the drive housing 17 can thus be prevented both during the spinning operation and when the rotor housing 15 is opened.

(19) The effect described can be improved even more if, similarly to FIG. 3, the intermediate chamber 18 is connected to the machine-long negative pressure line 33 or another negative pressure source 23 via a separate negative pressure channel 16a. Due to the sudden pressure compensation in the rotor housing 15 to the surrounding air pressure P.sub.U when the rotor housing 15 is opened, the pressure can also equalize in the negative pressure channel 16, so that the intermediate chamber 18 can now no longer be sufficiently impinged with negative pressure. By connecting the intermediate chamber 18 by means of its own negative pressure channel 16a, the negative pressure (air pressure P.sub.ZK) in the intermediate chamber 18 can still be maintained after opening the rotor housing 15. Alternately to an own negative pressure channel 16a for the intermediate chamber 18, it is also possible to arrange the third opening 22 or the connection of the intermediate chamber 18 to the negative pressure channel 16 near the machine-long negative pressure line 33 or connect the intermediate chamber 18 directly to the machine-long negative pressure line 33. Owing to the spatial proximity to the machine-long negative pressure line 33, sufficient negative pressure still prevails in this area even when the rotor housing 15 is opened.

(20) Since FIG. 3 shows a variation of the open-end spinning device of FIG. 2, only the differences to the device shown in FIG. 2 will be discussed below; the same elements and modes of operation will no longer be described separately. According to FIG. 3, it is also foreseen for the intermediate chamber 18 to be connected to a negative pressure source 23 through a third opening 22. For the pressure equalization reasons given in FIG. 2 that also occur in the negative pressure channel 16 when the rotor housing 15 is opened, the intermediate chamber 18 is also connected here to the negative pressure source 23 through its own negative pressure channel 16a. Naturally, and depending on the geometric conditions of the open-end spinning device 1, the intermediate chamber 18 could be connected directly to the machine-long negative pressure line 33. Compared to the open-end spinning device 1 of FIG. 2, however, the third opening 22 has been provided with a controllable shut-off device 26, so that the intermediate chamber 18 is not constantly in contact with the negative pressure source 23 but only until the lid 27 is opened. Due to the connecting openings 19 and 20 to the rotor housing 15 impinged with spinning negative pressure P.sub.SU, however, a negative pressure sets in also in the intermediate chamber 18 and in the drive housing 17 during the spinning operation. According to the present description, a sensor 32 is provided to achieve this, either in the area of the lid 27 of the rotor housings 15 or in the area of the swivel housing 29 to register the opening of the rotor housing 15 and the shut-off device 26 opens as a result of this. The intermediate chamber 18 is therefore further impinged with a negative pressure also when the lid 27 of the rotor housing 15 is opened, thus preventing impurities from being sucked into the drive housing 17. Any deposits from the rotor housing 15 area are also transported away via the third opening 22 and the negative pressure channel 16a after the shut-off device 26 is opened.

(21) Due to the fact that the intermediate chamber 18 is in any case impinged with spinning negative pressure P.sub.SU when the rotor housing 15 is opened, any impurities from the rotor housing 15 are sucked out through the negative pressure channel 16a and no longer reach the drive housing 17. The penetration of impurities into the drive housing 17 can therefore be prevented with all bearing types. However, this effect can be enhanced even more if—as in the description for FIG. 2—the axial bearing 24 is executed as axial air bearing 24a or the bearing comprises an air bearing. In this case, a higher air pressure P.sub.AG will always prevail in the drive housing 17 than the air pressure P.sub.ZK in the intermediate chamber 18. As a result of this, the sucking of impurities is once again prevented.

(22) FIG. 4 shows another variation of the open-end spinning device 1 shown in FIG. 2 with an intermediate chamber 18 impinged with negative pressure, in which the intermediate chamber 18 is connected to the negative pressure channel 16 of the rotor housing 15 via the third opening 22. To prevent the negative effect of pressure equalization in the negative pressure channel 16 described already under FIG. 2 when the rotor housing 15 is opened, instead of providing a separate negative pressure channel 16a, it can also be closed against the negative pressure channel 16 when the rotor housing 15 is opened. To do this, the rotor housing 15 is provided with a shut-off device 26 that blocks or allows its connection to the negative pressure channel 16. To control the shut-off device 26, a purely mechanical coupling can be provided with the lid 27 of the rotor housing or a sensor-controlled drive, similar to what FIG. 3 shows.

(23) Here, a slider 26a is provided as shut-off device 26 that connects the rotor housing 15 and the intermediate chamber 18 alternately with the negative pressure channel 16. During a regular spinning operation, the rotor housing 15 is connected to the negative pressure channel 16 to maintain the spinning negative pressure p.sub.SU in the rotor housing 15 in the usual way. On the other hand, the intermediate chamber 18 is closed against the negative pressure channel 16 during the regular spinning operation. Nonetheless, owing to the connective opening 19 towards the rotor housing, a negative pressure builds up in the intermediate chamber. The slider 26a can now be controlled in such a way that when the rotor housing 15 is opened, the connection of the rotor housing 15 to the negative pressure channel 16 is closed, while the third opening 22 is opened and the intermediate chamber 18 is now connected to the negative pressure channel 16. Thus, pressure equalization with the surrounding air pressure P.sub.U takes place only in the opened rotor housing 15, but not in the negative pressure channel 16, while the intermediate chamber 18 continues to be impinged with negative pressure through the third opening 22.

(24) The advantage of this embodiment is that no separate negative pressure line 16a is necessary for the intermediate chamber 18 to maintain the negative pressure in the intermediate chamber 18, even while and after the rotor housing 15 is opened. Additionally, owing to the fact that during the spinning operation the intermediate chamber 18 is closed against the negative pressure channel 16, no air current is generated from the rotor housing 15 through the intermediate chamber 18 into the negative pressure channel 16; rather, an advantageous air current is generated from the drive housing 17 through the intermediate chamber 18 into the rotor housing 15. As a result of this, dirt deposits can largely be prevented in the intermediate chamber 18.

(25) If full spinning negative pressure P.sub.SU prevails in the intermediate chamber 18 even with an opened rotor housing 15 in such a solution, then no dirt will be sucked into the drive housing 17 when the rotor housing 15 is opened; rather, impurities will be sucked out by the intermediate chamber 18 in the negative pressure channel 16. Such a solution therefore differs from the drawing shown in FIG. 4 and can be used even if no axial air bearing 24a is provided.

(26) Another embodiment of the open-end spinning device 1 with an intermediate chamber 18 impinged with negative pressure, usable especially for bearings without an axial air bearing 24a, is shown in FIG. 5. Here, the intermediate chamber 18 is connected to a negative pressure source 23 by means of an own negative pressure channel 16a, as described in FIG. 3. However, another alternative is also possible, namely to provide only one negative pressure channel 16 and to block off the rotor housing 15 against the negative pressure channel 16 when it is opened by means of a shut-off device 26. With regard to possible embodiments of the shut-off device 26, please refer to the explanation in FIG. 3.

(27) Furthermore, the drive housing 17 is provided with a purge opening 35, through which the drive housing 17 can be supplied temporarily, preferably when the rotor housing 15 is opened, with dust-free purge air to flush out the impurities that could have penetrated the drive housing 17 to the intermediate chamber 18. To supply filtered surrounding air to the drive housing 17 with the surrounding air pressure p.sub.U, the purge opening 35 is provided with a filter 30 or is connected to a filter 30.

(28) According to this explanation, a purge line 36 is connected to the purge opening 35 that is, in turn, provided with a filter 30 and is closed by the lid 27 of the rotor housing 15 during the spinning operation. When the rotor housing 15 is opened, the purge line 36 is then connected to the surrounding air, so that dust-free purge air is supplied to the drive housing 17. Since purging takes place only when the rotor housing 15 is open, the purge opening 35 can be of relatively generous dimensions so fast thorough purging can be achieved.

(29) A further embodiment of an open-end spinning device 1, in which the penetration of impurities into the drive housing 17 is prevented, is shown in FIG. 6. Unlike in FIGS. 2 and 3, the intermediate chamber 18 is constantly impinged with surrounding air pressure P.sub.U or is connected to it. In this spinning device 1, an air current is generated due to the intermediate chamber 18 from the third opening 22 through the first connective opening 19 into the rotor housing 15. Thus, no negative pressure occurs in the drive housing 17 even during the spinning, but depending on the bearing type used therein, either the surrounding air pressure P.sub.U too or, if an axial air bearing 24a is used, an increased air pressure P.sub.AG compared to the surrounding air pressure P.sub.U. Different from the drawing shown with an axial air bearing 24a, it is therefore just as possible to use the spinning device 1 in connection with other bearing types.

(30) The relationships during the regular spinning operation are shown in FIG. 6, as in FIGS. 2 and 3. Since no negative pressure builds up in the drive housing 17 during the spinning operation, air carrying the respective impurities cannot be sucked in any longer even if the rotor housing 15 is opened. To keep preventing the sucking in of impurities through the third opening 22 and the connecting opening 19 into the rotor housing 15, it is advantageous to provide the third opening 22 with an air filter 30, as shown in FIG. 6.

(31) The invention is not restricted to the embodiments shown. Variations and combinations as part of the patent claims fall also under the invention.

LIST OF REFERENCE CHARACTERS

(32) 1 Open-end spinning device 2 Rotor spinning machine 3 Spinning rotor 4 Rotor cup 5 Rotor shaft 6 Fiber material 7 Yarn 8 Feeding device 9 Dissolving device 10 Draw-off device 11 Winding device 12 Bobbin 13 Bearing 14 Individual drive 15 Rotor housing 16 Negative pressure channel 17 Drive housing 18 Intermediate chamber 19 first connecting opening 20 second connecting opening 21 Ring seal 22 third opening 23 negative pressure source 24 Axial bearing 24a Axial air bearing 25 Radial bearing 25a Radial magnet bearing 26 Shut-off device 26a Slider 27 Lid of the rotor housing 28 Seal of the rotor housing 29 Swivel housing 30 Air filter 31 Pressurized air source 32 Sensor 33 Negative pressure line 34 Draw-off nozzle 35 Purge opening 36 Purge line P.sub.U Surrounding air pressure p.sub.SU Spinning negative pressure p.sub.AG Air pressure in the drive housing p.sub.ZK Air pressure in the intermediate chamber