Method for supporting a spinning rotor and bearing system, spinning rotor and support bearings

Abstract

A bearing system and associated method of operation are provided to support a spinning rotor having a pot and a shaft of an open-end spinning device with two radial bearings and at least one axial support bearing, wherein at least one of the radial bearings is an active magnetic bearing. The axial support bearing is configured such that a magnetic bearing acts in opposition to one or both of an aerostatic air bearing or a mechanical starting element.

Claims

1. A bearing system of a spinning rotor having a pot and a shaft of an open-end spinning device, comprising: radial bearings, wherein at least one of the radial bearings is an active magnetic bearing; an actively controlled axial support bearing comprising a magnetic bearing configured at an end of the shaft that, during normal spinning operations, acts in equilibrium opposition to an oppositely directed force from an actively controlled electrical coil; and wherein the electrical coil is configured to act on the shaft of the spinning rotor to controllably apply pulling or compressive forces on the spinning rotor.

2. The bearing system according to claim 1, wherein the equilibrium is maintained such that the axial support bearing is a contact-free bearing relative to the shaft of the spinning rotor.

3. The bearing system according to claim 1, wherein the axial support bearing further comprises a control board for the control of the electrical coil.

4. The bearing system according to claim 1, wherein the magnetic bearing comprises a magnet arranged at the end of the shaft of the spinning rotor.

5. The bearing system according to claim 4, wherein the magnet is surrounded by a non-magnetic material.

6. The bearing system according to claim 1. wherein the magnetic bearing comprises a magnet arranged on a holder of the axial support bearing.

7. The bearing system according to claim 1, further comprising a mechanical starting element directed towards the end of the shaft of the spinning rotor comprising one of a flat or protruding contact point oriented towards an end of the shaft of the spinning rotor.

8. A bearing system of a spinning rotor having a pot and a shaft of an open-end spinning device, comprising: radial bearings, wherein at least one of the radial bearings is an active magnetic bearing: an actively controlled axial support bearing comprising a magnetic bearing configured at an end of the shaft that, during normal spinning operations, acts in equilibrium opposition to an oppositely directed repulsive force from an actively controlled aerostatic bearing; and wherein the aerostatic bearing builds up an air cushion between the end of the shaft of the spinning rotor and the aerostatic bearing, and further comprising a mechanical starting element that is directed towards the end of the shaft of the spinning rotor, the aerostatic bearing comprising at least one opening through the mechanical starting element for directing air to build up the air cushion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages of the invention are described in the following embodiments. The following is shown:

(2) FIG. 1 is a schematic overall view of a spinning rotor with a drive and a bearing system;

(3) FIG. 2 is a sectional view of a shaft end of a spinning rotor;

(4) FIG. 3 is an active axial bearing system in a sectional view;

(5) FIG. 4 is a front view of FIG. 3;

(6) FIG. 5 is a detail in the area of the shaft end and an electromagnetic axial bearing system;

(7) FIG. 6 is a detail in the area of the shaft end and a pneumatic axial bearing system;

(8) FIG. 7 is a detail in the area of the shaft end and a pneumatic axial bearing system with a permanent magnet;

(9) FIG. 8 is a detail in the area of the shaft end and a mechanical starting element with a permanent magnet; and

(10) FIG. 9 is a detail in the area of the shaft end and a pneumatic axial bearing system with a permanent magnet in a cartridge.

DETAILED DESCRIPTION

(11) 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.

(12) FIG. 1 shows a schematic illustration of a spinning rotor 1 with a motor 2 as its drive and an axial support bearing 6 of the spinning rotor 1. The spinning rotor 1 features a pot 3 that is connected to a shaft 4. The connection between the pot 3 and the shaft 4 can take place firmly, for example by welding, pressing or gluing. However, it can also represent a detachable connection, by which the pot 3 is interchangeably held by the shaft 4. The shaft 4 is the rotating rotor of the motor 2 and thereby can be set in a rotary motion. In this manner, more than 200,000 revolutions/min of the shaft 4, and thus of the spinning rotor 1, can be generated.

(13) In this embodiment, the bearing system of the spinning rotor 1 consists of two active radial bearing systems 5 and an active axial bearing 6. In two degrees of freedom, the active radial bearings 5 support the shaft 4 between electromagnets without contact. As long as they are supplied with energy, it is possible to position the shaft 4 between them without contact. Although, given their design, the active radial bearing systems 5 effect a certain axial guidance of the shaft 4, this is not sufficient in many applications. External forces that can act on the spinning rotor 1, such as, for example, the negative pressure in the rotor housing, the feeding of fibers or the abrupt interruption of the fiber feed, or pressure differences in the individual spinning phases, can effect an axial displacement of the shaft 4. To largely avoid this, the active axial bearing 6 is provided; it is preferably arranged at the end of the shaft 4, which is opposite to the pot 3.

(14) The active axial support bearing 6 comprises a holder 7 for fixing a coil 8 and a core 9 along with a control board 10. The coil 8 surrounds the core 9 and is controlled by the control located on the board 10. Electromagnetic forces, which act through the holder 7 on the shaft 4 of the spinning rotor 1, are generated through the coil 8. Depending on the polarity of the voltage applied at the coil 8, such electromagnetic forces attempt to repel or attract the shaft 4. With a magnet 11, which is arranged at the end of the shaft 4 on the spinning rotor 1 and which works together with the core 9, an attractive force that compensates for the repulsion of the electromagnetic forces or enhances the attraction by the electromagnetic forces is generated. The control on the board 10 causes the distance between the axial support bearing 6 and the shaft end to remain largely the same, by the repulsion of the shaft 4 taking place with more or less strength. In order to largely avoid reciprocal effects between the attraction and repulsion, a non-magnetic material 12 (for example, aluminum) is arranged between the magnetizable material of the shaft 4 at its end and the magnet 11.

(15) FIG. 2 shows the end of the shaft 4 of the spinning rotor 1 in a longitudinal section. The shaft 4 is formed as a hollow shaft, in which a magnet holder 13 is inserted and attached with an extension. The magnet holder 13 supports the magnet 11. The non-magnetic material 12, such as aluminum, surrounds the magnet 11 in an annular manner, and is also received in the magnet holder 13.

(16) In another embodiment, the magnet 11 and the non-magnetic material 12 may also be received directly in the shaft 4. For manufacturing reasons and for the variable design of the shaft end 4, a corresponding magnetic holder 13 can be used. Depending on which axial bearing the shaft 4 faces, instead of a magnet 11 or in addition to the magnet 11, a suitable friction surface for an air bearing can be used at this place. For example, such an air bearing has been offered for some time under the name Aerolager by Rieter. For example, the controlled air bearing can apply the compressive force at the shaft end, and the magnet can apply the pulling force counteracting the compressive force.

(17) FIG. 3 shows a section through an active magnetic bearing as an axial support bearing 6. The axial support bearing 6 is essentially received in the holder 7. The holder 7 also serves the purpose of attaching the axial support bearing 6 in a carrier (not shown) of the spinning device. The holder 7 is formed to be pot-shaped. The core 9, which is connected to the holder 7, is arranged in the holder 7. The core 9 features tiered taperings, whereas one of such taperings is surrounded by the coil 8. There is insulation 15 between the coil 8 and the core 9. The coil 8 is connected to the control board 10 with an electrical line 14, and can be controlled accordingly in order to exert a compressive force on the shaft 4. Thereby, the distance of the magnet 11 and the spinning rotor 1 from the stationary axial bearing 6 is kept constant or at a defined distance, as the case may be.

(18) A distance sensor that measures the distance between the spinning rotor 1 and the axial support bearing 6 is arranged on the board 10. Depending on the signal of this sensor, the coil 8 is acted upon by more or less current or alternating voltage, as the case may be, in order to exert a more or less strong compressive force or pulling force on the spinning rotor 1, and thereby bring this to the desired position against or in addition to the magnetic force. Through the arrangement of the board 10 on the core 9, a compact design is achieved, which receives both the controller and the sensor as a structural unit with the axial bearing 6.

(19) On the holder 7, a starting element 16 is arranged directly opposite the spinning rotor 1. Such starting element 16 is a favorable friction surface to the shaft end of the spinning rotor 1 and, in the event that the axial bearing 6 fails, causes the spinning rotor 1 to stop without damage to the axial bearing 6 and in a predetermined manner, also without the radial bearing 5 allocated to the spinning rotor 1 being damaged. The starting element 16 may be made of ceramic (for example) in order to protect the axial bearing 6 upon a collision with the spinning rotor 1. However, the starting element 16 can also be designed, for example, as a carbon element or can be made of plastic in order to ensure trouble-free sliding until the spinning rotor 1 is stopped.

(20) For better clarity, FIG. 4 also shows a front view of the axial bearing 6. It is evident from this that the board 10 is allocated to the axial bearing 6. The starting element 16 is cut out in the area of the board 8, in order to avoid a collision of the spinning rotor 1 with the board 10. Fasteners, through which the axial support bearing 6 can be attached to the spinning unit, are indicated on the holder 7.

(21) For a better illustration of the design of the axial support bearing 6, FIG. 5 once again presents an enlarged illustration of the interaction between the end of the shaft 4 or the magnet holder 13, as the case may be, and the side of the bearing system 6 turned towards the end of the shaft 4. With this view, it is evident that the magnet 11 faces the tapered core 9. The core 9 consists of magnetizable material. The magnet 11 attempts to attract the core 9. In contrast, the coil 8 acts on the spinning rotor 1, in particular through a collar 17 of the holder 7 on the annular edge 18 of the spinning rotor 1, and attempts to repel it. By changing the repulsive force by means of a modified power supply to the coil, the attraction force of the magnet 11 is more or less overcome and the spinning rotor 1 is kept in balance. Thus, the magnet 11 attracts the spinning rotor 1 at the core 9, while, with a corresponding supplying of current, the coil 8 attempts to push the spinning rotor 1 away. Through the interaction between the pulling force of the magnet 11 and the pressing force of the spool 8, the spinning rotor 1 is kept in balance and a designated distance from the bearing system 6 is maintained. On the other hand, through the forces acting on the spinning rotor 1, it may also be necessary for the magnetic force to have to be increased in order to keep the spinning rotor 1 in the desired position. In this case, by reversing the polarity of the voltage acting on the coil 8, the spinning rotor 1, in addition to the magnetic force, is pulled in its direction. The insulation 15 ensures that, when the coil 8 is energized, the electromagnetic waves interact through the holder 7 or the collar 17, as the case may be, with the annular edge 18 of the magnet holder 13.

(22) In order to ensure a controlled start-up of the spinning rotor 1 at the axial support bearing 6, the starting element 16 is arranged between the collar 17 and the annular edge 18.

(23) If the power supply of the coil 8 fails, the shaft 4 is pulled over the permanent magnet 11 in the direction of the core 9 and makes contact with the starting element 16. The starting element 16 slightly projects above the board 10, such that the spinning rotor 1 cannot make contact with and damage the board 10.

(24) Instead of the electromagnetically acting axial support bearing 6 with an electromagnetic coil 8, as shown here, an air bearing may be present instead of such electromagnetic coil 8. In this case, on the one hand, the spinning rotor 1 would be attracted to the axial bearing 6 because of the magnet 11 and the core 9. In this embodiment, instead of the coil 8, in particular centrally positioned in the core 9, one or more air openings 19 (FIG. 6) that direct compressed air against the end of the shaft 4 of the spinning rotor 1 are present. By means of an air flow that is more or less strong, which presses against the shaft 4, a repulsive force, which overcomes the attraction force of the magnet 11, is generated. By controlling such air flow, the spinning rotor 1 is to be kept in balance in the same manner as with the electromagnetic coil 8. This is illustrated schematically in FIG. 6. The change to compressed air can be achieved by a controllable valve.

(25) FIG. 7 shows such a detail in the area of shaft end and pneumatic axial bearing with a permanent magnet 11. Here, the permanent magnet 11 is not arranged on the shaft 4, as described above, but on the holder 7. With this, the magnet 11 is located in the starting element 16 and is covered by it in the direction of the shaft 4. Nevertheless, its magnetic force continues to act on the shaft 4 made of a ferromagnetic material, and attracts it. The starting element 16 consists of a material that gives rise to a good slide pairing with the shaft end. For example, if the shaft end is made of steel, the starting element 16 may be made of carbon or a plastic such as polyimide. If the shaft 4 starts against the starting element 16, the two parts slide on each other, without causing excessive wear. As such, an exchange of the starting element 16 will rarely be required. Moreover, the friction losses are low, such that the energy consumption, especially during start-up of the spinning rotor, is low.

(26) Air openings 19 are arranged in the starting element 16. For example, they surround the permanent magnet 11. On the side of the starting element 16 turned towards the permanent magnet 11, excess pressure is applied, such that air flow is directed against the shaft end. Together with the attractive force of the magnet 11, the repulsive force of the air flow gives rise to an equilibrium that keeps the shaft 4 in a stable state. The material of the starting element 16 may also be porous, such that the air diffuses through the starting element 16.

(27) FIG. 8 shows an additional alternative detail in the area of the shaft end and mechanical starting element 16 with a permanent magnet 11. The structure is similar to FIG. 7, but the starting element 16 with air openings 19 is replaced by a starting element 16 with a central projection 20. The shaft 4 can be supported on this projection 20 as needed. This results in a punctiform contact point, which is subject to less friction. The projection can be formed in one piece with the starting element 16, or can be used as a separate component, for example as a ball or a ball section in the starting element 16. As a material for this, steel or ceramic is advisable. The shaft end can also be reinforced with a ceramic insert.

(28) FIG. 9 shows a design similar to the design according to FIG. 7. The starting element 16 and the magnet 11 are arranged in a replaceable holder 7, which is constructed in the form of a cartridge. The holder 7 features an air connection 21, which can be connected to an excess pressure line (not shown) and an excess pressure source. Thereby, the cartridge can be pressurized in order to generate a flow from the air openings 19, which acts against the force of the magnet 11 on the shaft 4. The holder 7 is attached, for example, by means of screws or a thread on a housing 22 of the spinning station. The design shown here facilitates the manufacture and assembly of the axial bearing, since all important components are combined into one component. Of course, the other embodiments may be constructed by means of such a cartridge.

(29) This invention is not limited to the illustrated and described embodiments. Variations within the scope of the claims, just as the combination of characteristics, are possible, even if they are illustrated and described in different embodiments.

LIST OF REFERENCE SIGNS

(30) 1 Spinning rotor 2 Motor 3 Pot 4 Shaft 5 Radial bearing system 6 Axial support bearing system 7 Holder 8 Coil 9 Core 10 Board 11 Magnet 12 Non-magnetic material 13 Magnet holder 14 Line 15 Insulation 16 Starting element 17 Collar 18 Edge 19 Air opening 20 Projection 21 Air connection 22 Housing