Spinning rotor bearing system for a rotor spinning device having a rotor shaft and a bearing unit

Abstract

This invention relates to a spinning rotor bearing system for a rotor spinning apparatus, comprising a rotor shaft (10) of a spinning rotor (2) and a bearing unit (1) for a radial and axial combined bearing for the rotor shaft (10), the rotor shaft (10) comprising a permanent magnet (20) and an end face (18). The bearing unit (1) comprises a stator having a first axial yoke (11) and a second radial yoke (12), the first yoke (11) comprising a first diameter (D) J1 The first opening (8) of the yoke (12) includes a boss (14). The second yoke (12) includes a second diameter (D). J2 The second opening (9) of the first opening (8) forms a radial air gap (S) between the first opening (8) and the rotor shaft (10). R1 An axial air gap (S) is formed between the end face (18) and the boss (14). A An additional radial air gap (S) is formed between the circumferential surface of the rotor shaft (10) and the second yoke (12). R2 The permanent magnet (20) of the rotating cup shaft (10) is arranged between the first yoke (11) and the second yoke (12).

Description

Technical Field

[0001] This invention relates to the field of magnetic bearing technology, and more specifically to an axial / radial combined magnetic bearing for supporting the spinning rotor of a rotor spinning machine, capable of simultaneously absorbing axial and radial bearing forces. The spinning rotor bearing system of the rotor spinning machine includes a rotor shaft of the spinning rotor and bearing units for a radial and axial combined bearing of the rotor shaft, wherein the rotor shaft includes a first shaft diameter and a second shaft diameter, and at least one permanent magnet disposed between the first shaft diameter and the second shaft diameter, and has an end face extending radially toward the axis of the rotor shaft on one side of the permanent magnet, starting from the first shaft diameter of the rotor shaft. Background Technology

[0002] Magnetic bearings support a shaft (in this case, a rotor shaft) without material contact using magnetic force. The bearing force is typically generated by an adjustable electromagnet. Stability of the electromechanical system is ensured through appropriate feedback and electronic adjustment. Magnetic bearings often utilize a combination of electromagnetic bearings and permanent magnets. They can be designed as either axial or radial bearings. Often, both types of bearings need to be combined in a single machine to absorb axial and radial bearing forces relative to the axis of rotation of the supporting shaft. Machines such as electric motors or magnetic drives generally require two or more radial bearings and at least one axial bearing to maintain the rotor shaft in the desired position.

[0003] Patent document DE 19642471 A1 discloses a free-end rotor spinning device with a spinning rotor, wherein the rotor shaft is supported in the corner braces of two pairs of support discs, supported by axial bearings and operated by a single electric actuator, the stator of which is fixed to the spinning box housing. The rotor shaft is configured as a hollow shaft, and the rotor of the single electric actuator is integrated within the hollow shaft. However, the bearings of the rotor shaft are extremely inaccurate.

[0004] Patent document DE 102006053734 A1 discloses a rotor driver for a free-end spinning device. The rotor driver drives a rotor shaft forming the machine shaft and a rotor body arranged thereon. The rotor shaft and rotor body form a spinning rotor for spinning. The rotor shaft, as part of the rotor driver's rotor, is magnetically supported on both sides of the rotor driver. This support is achieved by means of two permanent magnet rings and a defined, excitable magnetic bearing coil. With the aid of these elements and sensing sensors, the axial position of the freely suspended spinning rotor during operation can be adjusted. This allows for relatively accurate determination and maintenance of the axial position of the shaft and the spinning rotor. However, the radial position of the rotor shaft and the spinning rotor varies within a wide tolerance range. Nevertheless, in order to spin uniform, uninterrupted filaments, the radial position of the spinning rotor is also extremely important, in addition to the axial position.

[0005] In modern free-end rotor spinning machines, the spinning rotor rotates at speeds up to 200,000 revolutions per minute. These rotors have a body into which fibers are fed and then drawn out as filaments. The diameter of the rotor body can exceed 20 mm, reaching a maximum of 40 mm. During rotor operation, the forces acting on the rotor body and bearings are extremely high. Stable and trouble-free rotor support is crucial, as it must produce the most uniform filaments possible while ensuring the safe and trouble-free operation of the spinning equipment.

[0006] Patent document WO 93 / 05310A1 discloses an axial magnetic bearing. A coil is wound around a shaft arranged between magnetic pole pieces of the stator. A magnetic field keeps the shaft radially centered between the coils. Support and centering can be achieved through an active adjustment system. Summary of the Invention

[0007] The purpose of this invention is to improve upon the known concept of supporting a rotor shaft using magnetic bearing technology. The bearings should be precise in both the axial and radial directions, and the rotor shaft should be easily installed and removed from the bearings.

[0008] To achieve the above objectives, the present invention provides the subject matter of the independent claims. Various embodiments and improvements are described in the dependent claims.

[0009] The spinning rotor bearing system of the rotor spinning apparatus according to the present invention includes a rotor shaft of a spinning rotor and a bearing unit for a radial and axial combined bearing for the rotor shaft. The rotor shaft includes a first shaft diameter and a second shaft diameter, and at least one permanent magnet disposed between the first shaft diameter and the second shaft diameter. Starting from the first shaft diameter of the rotor shaft, an end face extending radially toward the axis of the rotor shaft is arranged on one side of the permanent magnet. The bearing unit includes a stator having a first yoke and a second yoke, wherein the first yoke includes a first actuator coil and a first opening having a first diameter, in which a boss extending radially toward the axis of the first yoke is arranged. Axial support of the rotor shaft is achieved, in particular, by the first yoke. The second yoke includes at least two second actuator coils and a second opening having a second diameter. The second yoke is specifically for radial support of the rotor shaft. The first yoke and the second yoke are spaced apart from each other in the axial direction of the rotor shaft. When the rotor shaft is arranged in the bearing unit, during bearing operation, the first diameter of the first opening is larger than the first shaft diameter, such that a radial air gap is formed between the first opening and the rotor shaft. The end face of the rotor shaft interacts with the boss of the first yoke, creating an axial air gap between the end face and the boss. The second diameter of the second opening is larger than the second shaft diameter, creating another radial air gap between the circumferential surface of the rotor shaft and the second yoke. The permanent magnet of the rotor shaft is arranged between the first and second yokes so that when the coil is excited, bias flux is generated in both the axial air gap of the first yoke and the other radial air gap of the second yoke.

[0010] Typically, active magnetic radial bearings, for example, generate stable axial forces through magnetic reluctance, thus generally eliminating the need for a separate axial support bearing. However, significant forces still act on the spinning rotor, which can cause it to shift from its preset position. This drawback is that changes in the rotor's position, from which the yarn is produced, can lead to yarn unevenness or even fiber breakage. By using an additional axial support bearing, such as an active magnetic bearing, the spinning rotor can be axially supported to compensate for the axial forces acting upon it. Such axial forces, such as compression forces, are generated when fibers are fed into the rotor. On the other hand, the spinning rotor rotates within its housing, and pulling forces, for example, are generated by attraction present within the housing, acting on the spinning rotor.

[0011] The spinning rotor bearing system according to the invention serves as a combined bearing, with no contact in the axial and radial directions at least during spinning. Because the rotor shaft employs a non-contact bearing, the spinning rotor can operate energy-efficiently. The bearing unit occupies minimal structural space because it combines the axial and radial bearings of the rotor shaft. The axial and radial bearings cooperate, thus providing optimal axial and radial support for the rotor shaft as a whole during spinning operation. Using the combined bearing according to the invention, rotor shaft bearing adjustment can be achieved both axially and radially.

[0012] Advantageously, the first shaft diameter is equal to or smaller than the second shaft diameter and / or smaller than the diameter of the second opening. This allows the rotor shaft to be inserted into and removed from the bearing unit of the combined bearing from at least one side. This facilitates the assembly and disassembly of the rotor shaft, resulting in a cost-effective and easy-to-maintain spinning rotor bearing system.

[0013] Another advantage is that the rotor shaft is axially closed at the end face, or at least the second diameter of the rotor shaft is reduced to the first shaft diameter. When the rotor shaft is axially closed at the end face, the rotor shaft terminates here, within the bearing unit of the spinning rotor bearing system. The bearing unit can also be closed here, thus reducing the risk of contamination. If the diameter of the rotor shaft decreases only at the end face, it is likely that the rotor shaft will penetrate the bearing unit and continue beyond it. The bearing unit can then be located at the end of the rotor shaft or somewhere along the rotor shaft.

[0014] Another advantage is that the first and second yokes are interconnected, particularly via connecting plates. This further enhances the magnetic deflection applied to the rotor shaft by the bearing unit.

[0015] Another particularly advantageous feature is that the pole pieces of the second yoke are interconnected within the opening region of the rotor shaft by very thin (e.g., 0.5 mm to 1 mm wide) magnetic saturation tabs. Because the magnetic flux density distribution in the air gap between the stator and the shaft is very uniform, these magnetic saturation tabs connecting adjacent pole pieces minimize eddy current losses in the rotor. The magnetic saturation tabs are directly positioned in the gap between the pole pieces and the rotor shaft in the opening. Through these magnetic saturation tabs, the main magnetic flux is generated between the stator cross and the rotor shaft therebetween, rather than around the rotor shaft.

[0016] Advantageously, the rotor shaft terminates at the boss of the first yoke. This forms the end of the spinning rotor bearing system. This is advantageous both for introducing force axially and radially onto the rotor shaft and for the configuration of the entire structural unit, including the rotor actuator, and for the arrangement of the structural unit within the spinning unit of the spinning machine. Alternatively, if the rotor shaft extends through the first yoke, the spinning rotor bearing system can also be arranged, for example, near the rotor body in which the filaments are formed. While in the first alternative the rotor actuator is located between the bearing unit and the rotor body, in this second alternative the rotor actuator is arranged on the side of the bearing unit opposite the rotor body. For example, this may be advantageous for mounting sensors to determine the current position of the spinning rotor.

[0017] Another advantage is that the first or second diameter of the rotor shaft is constituted by elements connected to the rotor shaft, particularly permanent magnets and / or flux guides. This makes the rotor shaft configuration particularly simple to design. The permanent magnets and / or flux guides form their respective required diameters, which in turn makes the rotor shaft very simple to design in terms of construction and manufacturing technology.

[0018] Another advantage is that the end face is formed by an element connected to the rotor shaft. This allows the end face to be made of a material particularly conducive to magnetic flux, different from the rest of the rotor shaft. Thus, for example, when the spinning rotor accelerates, the natural frequency of the rotor shaft in the axial direction can play a particularly advantageous role.

[0019] Also advantageous is that the permanent magnet is axially magnetized and arranged within the central opening of the rotor shaft or around the circumference of the rotor shaft. Because the permanent magnet is arranged within the central opening of the rotor shaft, it is particularly simple and stable to secure the permanent magnet to the rotor shaft. If the permanent magnet is attached around the circumference of the rotor shaft, this has advantages in some embodiments regarding the axial positioning of the bearing unit relative to the rotor shaft.

[0020] Another advantage is that, particularly between the first and second yokes, at least one compensation coil is arranged coaxially with the first actuator coil to reduce the leakage flux of the first actuator coil in the radial air gap when properly excited. This achieves better decoupling of the generation of axial and radial forces.

[0021] Also advantageous is that the rotor shaft is equipped with a position sensor for determining the axial and / or radial position of the rotor shaft relative to the bearing unit. The position sensor can thus determine the current position of the rotor shaft, for example, by measuring the distance from a defined surface of the spinning rotor. The resulting signal can be used to adjust the appropriate position of the rotor shaft axially and / or radially via the bearing unit.

[0022] Advantageously, the rotor shaft is supported by a bearing unit and an additional bearing, particularly a radial magnetic bearing. While the bearing unit is located at one end of the rotor shaft, it may be particularly advantageous that the additional bearing is located at the other end. This allows the rotor shaft to be supported in a particularly stable position. This additional bearing (preferably a radial magnetic bearing) can be composed of permanent magnets. Compared to the active bearing in the combined bearing unit, this additional bearing typically functions only as a passive bearing, attempting to keep the rotor shaft as constant as possible in its position.

[0023] The bearing unit of the spinning rotor bearing system according to the invention includes a stator having a first axial yoke and a second radial yoke, wherein the first yoke includes a first actuator coil and a first opening having a first diameter. A boss extending radially toward the axis of the first yoke is arranged in the first opening. The second yoke includes at least two second actuator coils and a second opening having a second diameter. Each actuator coil is located at a magnetic pole piece of the second yoke. The midpoints of the two openings are concentrically aligned with each other and define an axial direction in which the rotor shaft can be axially oriented. The first and second yokes are spaced apart from each other in this axial direction. The bearing unit forms a combined bearing for radial and axial support of the rotor shaft. The bearing is movable, i.e., the position of the rotor shaft can be corrected using the bearing unit according to the invention when the actual position of radial concentricity and axial offset deviates from the target position radially and axially.

[0024] The rotor shaft according to the invention includes a first shaft diameter and a second shaft diameter, and at least one permanent magnet disposed between the first shaft diameter and the second shaft diameter. Starting from the first shaft diameter, the rotor shaft has an end face extending radially toward the axis of the rotor shaft on one side of the permanent magnet. The rotor can be supported relative to a bearing unit on the end face, and thus can be adjusted for support not only radially but also axially. The rotor shaft and the rotor body form a rotor for spinning. During operation, the rotor shaft is driven by a rotor driver. The rotor shaft, as part of the rotor driver's rotor, interacts with a coil of the rotor driver, which is stationary around the rotor shaft.

[0025] Another advantage is that the rotor body is positioned at one end of the rotor shaft. The rotor shaft and rotor body together form the spinning rotor for free-end rotor spinning machines. Fibers are fed into the rotor, and the high-speed rotation of the spinning rotor presses the fibers against the inner wall of the rotor. When the fibers are pulled out of the rotor, twisting occurs in the resulting fiber strands, thus forming yarn from the fibers.

[0026] Also advantageously, the permanent magnet is arranged at one of the ends of the rotor shaft. The permanent magnet can be particularly advantageously connected to the rotor shaft at this location. In this way, for example, the permanent magnet can be inserted into the central gap of the rotor shaft and fastened there, for example, by press fitting or adhesive.

[0027] This specification describes a device for supporting a rotor shaft. According to one example, the device includes at least one permanent magnet and a stator having a first yoke and a second yoke, the permanent magnet being connected to and thus rotatable with the rotor shaft. The first and second yokes are made of a soft magnetic material. The first yoke has an opening for insertion of the rotor shaft, such that an axial air gap is formed between the first yoke and an end face of the rotor shaft or a connected element thereto. Simultaneously, the first axial yoke is configured such that a first radial air gap is formed between the first yoke and the circumferential surface of the rotor shaft. The second radial yoke is arranged such that a second radial air gap is formed between the circumferential surface of the rotor shaft and the second yoke. The device also includes a first actuator coil disposed at the first yoke and two or more second actuator coils disposed at the second yoke. The permanent magnet is positioned relative to the first and second yokes to generate bias flux in both the axial and radial air gaps.

[0028] Since the permanent magnet is positioned at the rotor shaft, axial forces can be generated in two directions even though the rotor shaft and stator are not undercut.

[0029] These devices are configured according to the above description, wherein the features mentioned can exist individually or in any combination.

[0030] Various embodiments are described in detail below with reference to the examples shown in the accompanying drawings. The drawings are not necessarily to scale, and the invention is not limited to the aspects illustrated. Rather, the focus is on presenting the basic principles of the illustrated embodiments. Attached Figure Description

[0031] The following embodiments illustrate further advantages of the present invention. (See figures:)

[0032] Figure 1 An example perspective view of a bearing unit of a combined bearing according to the present invention is shown;

[0033] Figure 2 Show Figure 1 The image shows a transverse sectional view of a bearing unit of a combined bearing according to the present invention;

[0034] Figure 3 Show Figure 2 The magnetic field lines of the device shown;

[0035] Figure 4 Show Figure 1 The force effect of the coil current in the axial actuator coil of the combined bearing unit according to the present invention is shown.

[0036] Figure 5 Show Figure 1 The force effect of the coil current in the radial actuator coil of the combined bearing unit according to the present invention is shown.

[0037] Figure 6 A transverse sectional view of another embodiment of the bearing unit of the combined bearing according to the present invention is shown;

[0038] Figure 7 Another example is shown of a bearing unit with an additional compensation coil in a combined bearing according to the invention;

[0039] Figure 8 A cross-sectional view of the spinning rotor and the bearing unit of the combined bearing according to the present invention is shown;

[0040] Figure 9 A cross-sectional view showing another example of a spinning rotor and a bearing unit of a combined bearing according to the invention. Detailed Implementation

[0041] In the following description of the illustrated alternative embodiments, features in these embodiments that are the same as and / or at least equivalent to those in the embodiments described above are labeled with the same reference numerals. Unless otherwise specifically explained, their design and / or mode of operation correspond to the design and mode of operation of the features already described. For clarity, not all identical parts may be labeled with reference numerals, but they are drawn in the same manner. For greater clarity, in some figures, the rotor shaft is shown only in the bearing unit area of ​​the combined bearing.

[0042] According to the embodiments described herein, magnetic bearings can support a rotor (e.g., the rotor of an electric motor) in a non-contact manner by generating bearing forces (electromagnetic forces) in both the radial and axial directions. In addition to other non-contact bearings, the rotor can also be supported entirely non-contactly. According to the invention, the rotor is the rotor shaft 10 of a spinning rotor 2. Hereinafter, this combination of axial and radial bearings is also referred to as a combined bearing (axial / radial combined bearing). The axial direction is determined by the orientation of the rotor shaft's axis of rotation, defined in this specification as the z-direction, which, together with the x and y directions, forms a Cartesian coordinate system. Therefore, the radial bearing force lies in the xy-plane.

[0043] Figure 1 and Figure 2 A first embodiment of the bearing unit 1 of the combined bearing is shown, wherein Figure 1 This is a perspective view. Figure 2 This represents the relevant cross section of the xz plane. Figure 1 and Figure 2 The illustrated device includes a stator forming the bearing unit 1 and a rotor shaft 10 configured as a rotor. The stator may be arranged on or within the housing 29 of the spinning station in the rotor spinning equipment. The rotor shaft 10 may, for example, be the motor shaft of an electric motor that drives the spinning rotor 2. The stator includes all non-rotating components for generating and guiding magnetic flux. Similarly, the rotor includes the rotating rotor shaft 10 itself and those components connected thereto for generating and guiding magnetic flux and rotating with the rotor shaft 10.

[0044] The spinning rotor bearing system includes a combined bearing 1 and a rotor shaft 10 and has at least one permanent magnet 20, which is assembled in or on the rotor shaft 10 and rotates therewith. Therefore, the permanent magnet 20 is also called a rotor magnet. Figure 2 In the example shown, the permanent magnet 20 is arranged in the central opening 15 at the end of the rotor shaft 10, for example, coaxial with the axis of rotation. The rotor shaft 10 itself is preferably, but not necessarily, made of a non-ferromagnetic material, such as stainless steel, plastic, or other low-permeability materials. In some applications, the rotor shaft 10 may be designed as a hollow shaft. The permanent magnet 20 can be magnetized axially. Figure 2 In the diagram, arrows indicate the magnetization of permanent magnet 20.

[0045] like Figure 2 As shown, the permanent magnet 20 is disposed at the end of the rotor shaft 10. In other embodiments, the permanent magnet 20 may also be disposed at any axial position (z-coordinate) of the rotor shaft 10 (see also...). Figure 6 or Figure 9 ).exist Figure 2 In the example shown, the flux concentrator 13 (also referred to as a flux guide) is arranged axially adjacent to the permanent magnet 20. The flux concentrator 13 is made of a soft magnetic material and is used to guide magnetic flux, which is substantially locally confined within the flux concentrator 13. Optionally, the central opening 15 (e.g., a channel) may have an additional flux guide 19 at its axial end, which may form a cover for the central opening 15. The flux guide 19 may also be made of a soft magnetic material. However, the cover for the central opening 15 may be omitted or made of a different material.

[0046] Bearing unit 1 includes two soft magnetic elements. Hereinafter, one of these soft magnetic elements is referred to as radial yoke 12 or second yoke 12 because it guides magnetic flux radially. Radial yoke 12 may be a generally disc-shaped element extending radially (i.e., in or parallel to the xy-plane). The axial position (i.e., z-coordinate) of radial yoke 12 approximately corresponds to the axial position of flux concentrator 13 or the axial position of one end of permanent magnet 20. In some embodiments, flux concentrator 13 may be omitted, although this would result in increased leakage flux. Figure 2 In this configuration, the radial second yoke 12 is located beside the permanent magnet 20 relative to the z-direction. Generally, the yoke serves as part of the magnetic conduction path, i.e., the magnetic circuit, and therefore the radial yoke 12 is made of a soft magnetic material. A radial air gap S exists between the flux concentrator 13 and the radial yoke 12. R2 (See also) Figure 3 That is, the magnetic field lines pass through the air gap S essentially radially. R2 The term "air gap" generally does not imply that the gap contains only air, but rather refers to the presence of non-magnetic material within the gap. Accordingly, in this embodiment, in addition to air, there is also material of the rotor shaft 10, particularly the wall of the opening 15.

[0047] Another soft magnetic element is called the axial yoke, also known as the first yoke 11. Figure 2 In the example shown, the axial first yoke 11 is located beside the permanent magnet 20 along the z-direction, but on the side of the permanent magnet 20 opposite to the radial second yoke 12. The axial first yoke 11 is also used to guide magnetic flux and can, for example, have a shape similar to a pot magnet. In the example shown, the axial yoke 11 has a generally cylindrical shape, with one end of the rotor shaft 10 inserted into this cylindrical shape, such that a small axial air gap S is formed between the end face 16 of the rotor shaft 10 and the axial yoke 11. A The end face 16 forms the end face 18 of the boss 14 of the first yoke 11. In the axial air gap S A In this configuration, the magnetic field lines extend substantially axially between the rotor shaft 10 and the axial yoke 11. An additional radial air gap S is formed between the circumferential surface of the rotor shaft 10 and the yoke 11. R1 (see Figure 3 This allows us to deduce the magnetic properties.

[0048] The rotor magnet or permanent magnet 20 is connected by an axial yoke 11, a radial yoke 12, and an air gap S. R2 S A S X A magnetic field and a corresponding magnetic flux B are generated. BIAS In the example shown, the air gap S X Located between the axial yoke 11 and the radial yoke 12 in the axial z-direction, the air gap is significantly larger than other air gaps, thus resulting in a certain leakage flux (see...). Figure 3 Thus, the magnetic flux B generated by the rotor magnet or permanent magnet 20 BIAS Also known as magnetic bias or bias flux. The direction of magnetic field lines will be described in detail later. In some embodiments, the air gap S between the axial yoke 11 and the radial yoke 12 is... X It can also be bridged by ferromagnetic connector 17, such as Figure 9 As shown.

[0049] To generate axial force, the stator of the magnetic bearing has at least one coil 21 coaxial with the axis of rotation (z-axis) of the rotor shaft 10, hereinafter referred to as the "axial actuator coil". The axial actuator coil 21 can be arranged inside a pot-shaped axial yoke 11, similar to a pot magnet (electromagnet). More generally, the axial actuator coil 21 is formed by a soft magnetic element, i.e., the yoke 11, which guides the magnetic flux and forms an axial air gap S to the end face 16 of the rotor shaft 10. A and the radial air gap S to the circumferential surface of the rotor shaft 10 R1 Axial air gap S A The effective magnetic flux (total magnetic flux) is generated by the bias magnetic flux B induced by the permanent magnet 20. BIAS and the magnetic flux B caused by the axial actuator coil 21 21 This is generated by superposition. Based on the direction of the current in coil 21, the bias flux B generated by permanent magnet 20... BIAS In the axial air gap S A The force may be enhanced or weakened. According to the embodiments described herein, the axial force between the yoke 11 (stator portion) and the rotor shaft 10 can even change direction, i.e., from the negative z-direction of attraction to the positive z-direction of repulsion, and vice versa.

[0050] The aforementioned equipment also includes sensor devices (see Figures 1 to 3 The sensor device includes one or more position sensors 28 for measuring the axial and radial position of the rotor shaft 10, and associated electronic control devices that adjust the current passing through the axial actuator coil 21 and the radial actuator coils 22a-22d based on the measured position of the rotor shaft 10. The entire system, consisting of the stator, rotor, and electronic control devices for the magnetic bearings, can maintain the rotor shaft 10 in the desired axial position. The sensor device and electronic control devices will be described in detail later.

[0051] As mentioned above, for example from Figure 3 As can be seen from this, permanent magnet 20 uses magnetic flux B BIAS Biased axial air gap S A Therefore, the magnetic flux B BIASAlso known as bias flux. When no current flows through the axial actuator coil 21, an axial force in the negative z-direction usually acts on the rotor shaft 10, thus forming axial prestress. This force serves as the bias flux B. BIAS The result can be compensated, for example, by exciting actuator coil 21, thereby causing actuator coil 21 to generate magnetic flux (using B). 21 (Representation). Magnetic flux B 21 The bias flux B can be partially compensated, fully compensated, or overcompensated. BIAS .exist Figure 3 Combination Figure 4 In this case, Figure 4 In the middle (a), the bias flux B is represented. BIAS With magnetic flux B 21 Constructive superposition (coil current is positive, magnetic flux B) 21 Along the z-direction), and Figure 4 (b) represents the bias flux B BIAS With magnetic flux B 21 Destructive superposition (coil current is negative, magnetic flux B) 21 (in the opposite z direction).

[0052] In full compensation (B) BIAS +B 21 When the axial prestress is zero, the axial (net) force is zero, and the rotor shaft 10 is in its axial target position. However, to reduce energy consumption, additional bearings can be used to compensate for the axial prestress (see [reference]). Figure 8 and Figure 9 For example, the additional bearing could be a passive magnetic bearing 6. However, a second combined bearing or another bearing could be used to generate an axial prestress of approximately the same magnitude but in the opposite direction (i.e., along the z-direction) acting on the rotor shaft 10. In this case, a relatively small current through the axial actuator coil 21 is sufficient to keep the rotor shaft 10 in its unstressed position (target position).

[0053] As described above, the axial position of the rotor shaft 10 is continuously detected by the sensor device using its position sensor 28. The electronic control unit is configured to set the current through the axial actuator coil 21 such that the rotor shaft 10 always returns to its unloaded position or remains in that position (position adjustment). In this case, the current during magnetic bearing operation fluctuates around zero amperes. If, as described above, the axial prestress is not compensated or not fully compensated, the current in the axial actuator coil 21 fluctuates around a specific rated current during operation.

[0054] To reduce eddy current losses, in some embodiments, the soft magnetic elements that conduct magnetic flux (i.e., the radial second yoke 12 and the axial first yoke 11) may also be made of laminated metal sheets or, for example, soft magnetic composite material.

[0055] To generate radial bearing force, at least two, but particularly three or four actuator coils 22a-22d (here referred to as radial actuator coils 22a-22d) are arranged on the radial yoke 12. In the illustrated embodiment, the four actuator coils 22a-22d are magnetically coupled to the radial yoke 12. By properly exciting the radial actuator coils 22a-22d, any radial force can be generated in the xy plane, such as... Figure 5 The cross-sectional view is shown. As described above, the permanent magnet 20 is in the radial air gap S R2 The bias flux B is generated in the middle BIAS The magnetic flux B generated by coils 22a-22d 22 Depending on the direction of the current, they may either be constructive or destructive, resulting in superposition.

[0056] The rotor shaft 10 has a first shaft diameter d in the region of the first axial yoke 11. S1 The region of the second radial yoke 12 has a second shaft diameter d. S2 The permanent magnets 20 are arranged on two shafts with diameters d. S1 and d S2 Between. The end face 16 of the rotor shaft 10 begins from the first shaft diameter d. S1 And it extends radially toward the axis in the z-direction and further toward the axis of the rotor shaft 10. The first axial yoke 11 includes a first diameter D J1 The first opening 8 has a boss 14 extending radially toward the z-axis of the first yoke 11. The second yoke 12 includes the bearing unit 1 having a second diameter D. J2 The second opening 9. The first yoke 11 and the second yoke 12 are spaced apart by a distance S along the axial direction of the rotor shaft 10. x (see Figure 3 ).

[0057] When the rotor shaft 10 is arranged in the bearing unit 1, during bearing operation, i.e., in the position where the rotor shaft 10 is operably supported in the bearing unit 1, the first diameter D of the first opening 8 is... J1 Greater than the first shaft diameter d S1 Thus, a radial air gap S is formed between the first opening 8 and the rotor shaft 10. R1 (see Figure 3 The end face 16 of the rotor shaft 10 interacts with the boss 14 of the first yoke 11, creating an axial air gap S between the end face 16 and the boss 14. A The second diameter D of the second opening 9 J2 Greater than the second shaft diameter d S2 This creates an additional radial air gap S between the circumferential surface of the rotor shaft 10 and the second yoke 12. R2 .

[0058] from Figure 2 As can be seen from the illustration, in this embodiment, the first shaft diameter d S1 Equal to the second shaft diameter d S2 Therefore, the rotor shaft 10 can be removed from the bearing unit 1 in the positive z-direction because there is no undercut between the rotor shaft 10 and the bearing unit 1 in this direction. Removing the rotor shaft 10 from the bearing unit 1 is crucial for the simple and low-cost assembly and disassembly of the spinning rotor bearing system. When the first shaft diameter d... S1 Less than the second shaft diameter d S2 In particular, the diameter D of the second opening 9 at the radial yoke 12 is smaller than that of the second opening 9. J2 At the same time, such removal may also be achieved (see Figure 6 ).

[0059] Figure 3 The example shown illustrates the relationship with Figure 2 The same cross-section, Figure 3 The magnetically related air gap S is shown. R2 S R1 S A and S X And the bias flux generated by the rotor magnet 20 and the magnetic flux generated by the coil 21. Figure 5 The magnetic flux direction in the radial yoke 12 is schematically shown, especially in Figure 3 The magnetic flux of actuator coils 22a-22d not included in the calculation. Figures 3 to 5 In the diagram, the bias flux generated by the permanent magnet 20 is labeled as B. BIAS The associated magnetic field lines pass from the permanent magnet 20 through the radial air gap S. R2 Radial yoke 12, air gap S X (Possible magnetic flux leakage), axial yoke 11 and axial air gap S A Return to permanent magnet 20. In Figure 5 In the diagram, the symbol ⊙ usually represents magnetic field lines pointing out of the paper, while... This indicates the magnetic field lines pointing towards the paper. The same applies to the direction of current flowing through a coil (see, for example, [reference needed]). Figure 4 ).

[0060] The magnetic field generated by the axial actuator coil 21 is B 21 The associated magnetic field lines pass through coil 21 along the z-direction and through the air gap S. A and S R1 And yoke 12. As described above, Figure 5 The figure shows the magnetic flux B generated by the radial actuator coils 22a-22d. 22 However, it essentially passes through the radial yoke 12 and the air gap S. R2 , where magnetic flux B BIAS and B 22Superposition (total magnetic flux B) 22 +B BIAS Similarly, magnetic flux B BIAS and B 21 In the air gap d A Superimposed (total magnetic flux B) 21 +B BIAS ).from Figure 3 As can be seen from this, the permanent magnet 20 is in the radial air gap S R2 and axial air gap S A Bias flux B is generated in all of them. BIAS .

[0061] exist Figure 3 and Figure 4 ( Figure 4 In the case shown in (a)), the axial actuator coil 21 will enhance the magnetic flux B of the permanent magnet 20. BIAS This causes the tension on the rotor shaft 10 to increase against the z-direction. By changing the direction of the current in coil 21, the magnetic flux B generated by coil 21... 21 It will cancel the magnetic flux B of permanent magnet 20 BIAS This reduces the downward pull (see...) Figure 4 (b) Current direction is opposite). With the device shown, it is even possible to generate a force that moves the rotor shaft 10 in the z direction through appropriate design.

[0062] In the example shown, four radial actuator coils 22a-22d are provided. In principle, two or three coils would suffice. Figure 5 In the figure, through excitation coils 22a and 22c, a force is applied to the left in the negative x-direction to the rotor shaft 10. As shown in the figure, in the annular air gap S R2 In the left region, the generated magnetic flux increases compared to the prestress, while in the air gap S R2 In the right region, the generated magnetic flux is reduced compared to the prestress. If the current directions in coils 22a and 22c are reversed, a force is generated accordingly in the positive x-direction. In this theoretical case, the other two radial actuator coils 22b and 22d remain without current because they only need to generate a force in the y-direction.

[0063] If the rotor shaft 10 is in its target position, that is... Figure 2 When x = 0 and y = 0, the radial force is canceled out by magnetic deflection. This means that the radial actuator coils 22a-22d can be operated with an average current of zero amperes, resulting in relatively low energy consumption.

[0064] In the example described herein, the magnetically conductive radial yoke 12 shown is wound around four pole pieces, each pole piece having one of four coils 22a-22d. Figure 5The grooves 24 between the pole pieces of the yoke 12 shown can induce alternating magnetic flux components in the shaft clamp of the rotor shaft 10. To reduce eddy current losses in the conductive rotor shaft clamp, these grooves 24 can also be connected by thin tabs 25 (i.e., so-called magnetic saturation tabs).

[0065] To radially center the rotor shaft 10, in addition to the axial position (z-coordinate), the aforementioned sensor device continuously measures the radial position (x-coordinate and y-coordinate) of the rotor shaft 10 using its position sensor 28. The electronic control unit determines the current position of the rotor shaft 10 based on the sensor signals. The electronic control unit also includes position adjustment, comparing the measured position (x, y, z) of the rotor shaft 10 with a target position (e.g., (0, 0, 0)) and adjusting the current through actuator coils 21 and 22a-22d to adjust the air gap S. A and S R2 The magnetic force generated cancels out any deviation from the target position. For this purpose, the electronic control device can have a suitable power output stage (e.g., made of (MOS) transistors). Suitable electronic control devices are well known and will not be described further herein.

[0066] In the example described so far, the end of the rotor shaft 10 is inserted into the axial first yoke 11, a design similar to a pot magnet. However, this is not always the case. Figure 6 In the example shown, the rotor shaft 10 extends through the axial yoke 11. In this example, the permanent magnet 20 can be arranged in a ring around the outer circumference of the rotor shaft 10. The same applies to the optional flux guide 19. Magnetic lines of force and magnetic flux (biased flux B) BIAS and coil B 21 and B 22 The direction of the magnetic flux is not significantly different from the previous example; please refer to the above text, especially in conjunction with... Figure 4 and Figure 5 The content described above. In this example, the axial air gap S A It is not between the end face 16 of the axial yoke 11 and the rotor shaft 10, but between the end face 18 of the axial yoke 11 and the shaft platform, shaft shoulder, or part connected to the rotor shaft 10 (e.g., flux guide 19 or permanent magnet 20).

[0067] In the example described herein, the rotor magnet 20 is magnetized axially. Specifically... Figure 6 In the example, the permanent magnet 20 can also be configured as a radial magnetization ring. In this case, the permanent magnet 20 will be positioned at the location of the flux guide, which will no longer be needed. Furthermore, the permanent magnet 20 does not necessarily have to be cylindrical or annular, as long as the flux guide 19 is adapted to the shape of the yokes 11 and 12 or the air gap S. R1 S R2 S A and SX The shape is acceptable. Therefore, the rotor shaft 10 has a diameter d in the region of the position sensor 28 and yoke 12, together with the flux guide 19 and the permanent magnet 20. S2 The diameter d S2 The diameter D of the opening 9 of the yoke 12 is smaller than that of the yoke 12. J2 It is also smaller than the diameter D of the opening 8 of the yoke 11. J1 In a further direction, the end face 16 of the rotor shaft 10 facing the rotor shaft 10 has a diameter d. S1 The diameter d S1 The diameter D of the additional opening 26 of the yoke 11 is smaller than that of the yoke 11. J3 The rotor shaft 10 can pass through the bearing unit 1 and can still be removed from the bearing unit 1 axially.

[0068] exist Figure 6 In the example shown, the positions of yoke 11 and yoke 12 can also be reversed, that is, the axial yoke 11 does not need to be arranged at the shaft end or the axial yoke 11 is closer to the end face 17 of the rotor shaft 10 than the radial yoke 12. Accordingly, the bearing unit 1 can be configured in a mirror-inverted manner.

[0069] Figure 7 A perspective cross-sectional view of another embodiment is shown. Figure 7 Examples and Figures 1 to 3 The example is essentially the same, except that an additional compensation coil 23 is arranged beside the radial yoke 12 when viewed from the z-direction. This is to minimize the leakage flux of the axial actuator coil 21 on the radial air gap S. R2 Medium bias flux B BIAS To mitigate the impact, an additional compensation coil 23 can be placed near the radial yoke 12. The compensation coil 23 can be arranged coaxially with the rotor shaft 10. Excitation of the compensation coil 23 causes the air gap S to... R2 The leakage flux of the central axial actuator coil 21 is almost completely canceled out by the flux of the compensation coil 23. This can be easily achieved by connecting the actuator coil 21 and the compensation coil 23 in series. This reduces axial coupling with the radial adjustment circuit that adjusts the axial or radial position of the rotor shaft 10. Please refer primarily to the description in conjunction with the above figures.

[0070] Figure 8 A cross-sectional view of the spinning rotor 2 and the bearing unit 1 of the combined bearing according to the present invention is shown. The bearing unit 1 corresponds to... Figures 1 to 5The structure and description of bearing unit 1 are presented. The driver 30 of spinning rotor 2 is shown in the central axial region of rotor shaft 10. The driver 30 of spinning rotor 2 includes a stationary coil 3 and a rotor magnet 4. The coil 3 is stationary and fixed in housing 29, while the rotor magnet 4 is fixed in rotor shaft 10. During operation of the driver 30 of spinning rotor 2, an electromagnetic field is generated, causing rotor shaft 10 and its rotor magnet 4 to rotate non-contactly within coil 3. Thus, rotor shaft 10 and spinning rotor 2 achieve rotational speeds up to approximately 200,000 rpm.

[0071] The rotor shaft 10 has a rotor body 5 located at its end opposite to the bearing unit 1. During the operation of the spinning equipment, single fibers are fed into the rotor body 5, and under the high-speed rotation of the spinning rotor 2, these fibers are pressed against the inner wall of the rotor body 5 and pulled out as twisted yarns along the central axis of the spinning rotor 2. This can cause imbalance, especially during yarn splicing, and must be balanced by bearings.

[0072] To ensure stable operation of the spinning rotor 2, the rotor shaft 10 is supported not only by the bearing unit 1 but also by additional bearings, particularly the radially acting magnetic bearing 6. The magnetic bearing 6 shown in this figure acts passively only. It does not adjust the precise position of the rotor shaft 10. Opposite-polarized permanent magnet rings 7a and 7b repel each other, thus guiding their concentric positioning and consequently, the concentric positioning of the rotor shaft 10. When the outer permanent magnet ring 7a is stationary on the housing 29, the inner permanent magnet ring 7b is fixed to the rotor shaft 10. The inner permanent magnet ring 7b is thus centered within the outer permanent magnet ring 7a. Stable support of the rotor shaft 10 is achieved by arranging multiple pairs of permanent magnet rings 7a and 7b side-by-side (four pairs in this embodiment). The alternating magnetization of adjacent pairs also generates higher radial stiffness of the rotor shaft 10. Axial force on the rotor shaft 10 can be generated by the axial misalignment between the permanent magnet rings 7a and 7b. In this way, the static axial force can be passively absorbed by the permanent magnet ring, that is, without consuming energy.

[0073] Figure 9 Another example is shown of the spinning rotor 2 and the bearing unit 1 of the combined bearing according to the invention. The design of the bearing unit 1 is substantially corresponding to... Figure 6The design is as follows: Bearing unit 1 is equipped with a position sensor 28 located near the rotor body 5. The position sensor 28 measures the distance to the collar 27 on the rotor body 5. An annular flux concentrator 13 and an annular permanent magnet 20 are arranged on the rotor shaft 10, corresponding to the axial yoke 11 and radial yoke 12. Following bearing unit 1 is a driver 30 for the rotor shaft 10, which has a coil 3 and a rotor magnet 4. The rotor shaft 10 terminates at a passive magnetic bearing 6, which has a stationary permanent magnet ring 7a and a permanent magnet ring 7b that rotates with the rotor shaft 10. By matching the diameter of the rotor shaft 10 with the openings of the yoke 11 and yoke 12, as well as other channels in the stator and permanent magnet ring 7a region of the driver 30 of the rotor shaft 10, in this embodiment of the invention, the spinning rotor 2 can also be removed from the spinning rotor bearing system without assembly work.

[0074] The shaft diameter d of the rotor shaft 10 S1 The rotor shaft 10 is equipped with components connected to it, including a permanent magnet 20 and two flux guides 19 or flux concentrators 13, thereby expanding the rotor shaft 10 to a diameter d. S2 The end face 18 that interacts with the first axial yoke 11 is correspondingly formed by one of these elements, here a flux concentrator.

[0075] This invention is not limited to the embodiments shown in the figures and described herein. The combination of features represented and described in different embodiments may also be covered within the scope of the claims.

[0076] List of reference numerals

[0077] 1 Bearing Unit

[0078] 2 Spinning rotor

[0079] 3. Coil (Stator)

[0080] 4. Rotor magnet

[0081] 5. Rotate the cup body

[0082] 6 magnetic bearings

[0083] 7a, 7b permanent magnet rings

[0084] 8. The first opening of the yoke 11

[0085] 9. Opening of yoke 12

[0086] 10-turn cup shaft

[0087] 11 First Yoke

[0088] 12 Second yoke

[0089] 13 Flux Concentrator

[0090] 14. Bosses

[0091] 15 Openings

[0092] 16 End Face

[0093] 17. Piece stitching

[0094] 18 end face

[0095] 19 Flux Guide

[0096] 20 permanent magnets

[0097] 21 Actuator coil

[0098] 22a-22d actuator coil

[0099] 23 Compensation coil

[0100] 24 Grooves

[0101] 25 stitched images

[0102] 26. Another opening

[0103] 27 collar

[0104] 28 Position Sensors

[0105] 29. Shell

[0106] 30 drives

[0107] B BIAS Magnetic flux

[0108] B 21 Magnetic flux

[0109] B 22 Magnetic flux

[0110] d S1 First shaft diameter

[0111] d S2 Second shaft diameter

[0112] D J1 First opening diameter

[0113] D J2 Second opening diameter

[0114] D J3 Other opening diameter

[0115] S A Axial air gap

[0116] S R1 radial air gap

[0117] SR2 radial air gap

[0118] S X The air gap between the first yoke and the second yoke

Claims

1. A spinning rotor bearing system for a rotor spinning apparatus, comprising a rotor shaft (10) of a spinning rotor (2) and a bearing unit (1) for a radial and axial combined bearing for said rotor shaft (10), in, The rotor shaft (10) includes a first shaft diameter (d) S1 ) and second shaft diameter (d S2 ) and arranged in the first shaft diameter (d S1 ) and the second shaft diameter (d S2 At least one permanent magnet (20) between the rotor shaft (10) and the first axial diameter (d) of the rotor shaft (10). S1 The permanent magnet (20) has an end face (18) on one side that extends radially toward the axis of the rotor shaft (10), and The bearing unit (1) includes a stator having an axial first yoke (11) and a radial second yoke (12), wherein, The first yoke (11) includes a first actuator coil (21) and a first diameter (D). J1 The first opening (8) of the first yoke (11) has a boss (14) extending radially toward the axis of the first yoke (11). The second yoke (12) includes at least two second actuator coils (22a-22d) and has a second diameter (D). J2 The second opening (9) of ) and The first yoke (11) and the second yoke (12) are spaced apart from each other in the axial direction of the rotor shaft (10). Wherein, when the rotor shaft (10) is arranged in the bearing unit (1), during bearing operation, The first diameter (D) of the first opening (8) J1 ) is greater than the first shaft diameter (d) S1 This creates a radial air gap (S) between the first opening (8) and the rotor shaft (10). R1 ), The end face (18) of the rotor shaft (10) interacts with the boss (14) of the first yoke (11), thereby forming an axial air gap (S) between the end face (18) and the boss (14). A ), The second diameter (D) of the second opening (9) J2 ) is greater than the second shaft diameter (d) S2 This creates an additional radial air gap (S) between the circumferential surface of the rotor shaft (10) and the second yoke (12). R2 ),and The permanent magnet (20) of the rotor shaft (10) is arranged between the first yoke (11) and the second yoke (12) so that when the coils (21, 22a-22d) are excited, the permanent magnet (20) in the axial air gap (S) of the first yoke (11) is filled with a permanent magnet. A The additional radial air gap (S) in the second yoke (12) and the second yoke (12) R2 Bias flux (B) is generated in all of them. BIAS ).

2. The spinning rotor bearing system according to claim 1, characterized in that, The first shaft diameter (d) S1 ) equal to or less than the second shaft diameter (d) S2 ) and / or a second diameter (D) smaller than the second opening (9) J2 ).

3. The spinning rotor bearing system according to claim 1, characterized in that, The end face (18) axially closes the rotor shaft (10) or makes the second diameter (d) of the rotor shaft (10) of the rotor shaft (10) smaller. S2 ) reduced to the first shaft diameter (d S1 ).

4. The spinning rotor bearing system according to claim 1, characterized in that, The first yoke (11) and the second yoke (12) are connected to each other.

5. The spinning rotor bearing system according to claim 4, characterized in that, The first yoke (11) and the second yoke (12) are connected to each other by a connecting piece (17).

6. The spinning rotor bearing system according to claim 1, characterized in that, The rotating cup shaft (10) terminates at the boss (14) of the first yoke (11) or passes through the first yoke (11).

7. The spinning rotor bearing system according to claim 1, characterized in that, The first shaft diameter (d) of the rotor shaft (10) S1 ) or second shaft diameter (d S2 It consists of elements connected to the rotor shaft (10).

8. The spinning rotor bearing system according to claim 7, characterized in that, The first shaft diameter (d) of the rotor shaft (10) S1 ) or second shaft diameter (d S2 It is composed of the permanent magnet (20) and / or the flux guide (19).

9. The spinning rotor bearing system according to claim 7 or 8, characterized in that, The end face (18) is formed by an element connected to the rotor shaft (10).

10. The spinning rotor bearing system according to claim 1, characterized in that, The permanent magnet (20) is axially magnetized and arranged in the central opening (15) of the rotor shaft (10) or around the circumference of the rotor shaft (10).

11. The spinning rotor bearing system according to claim 1, characterized in that, At least one compensation coil (23) is arranged coaxially with the first actuator coil (21) to reduce the first actuator coil (21) in the radial air gap (S) when properly excited. R1 The leakage flux in ).

12. The spinning rotor bearing system according to claim 11, characterized in that, The at least one compensation coil (23) is arranged coaxially with the first actuator coil (21) between the first yoke (11) and the second yoke (12).

13. The spinning rotor bearing system according to claim 1, characterized in that, The rotor shaft (10) is equipped with a position sensor (28) for determining the axial and / or radial position of the rotor shaft (10) relative to the bearing unit (1).

14. The spinning rotor bearing system according to claim 1, characterized in that, The rotor shaft (10) supports the bearing unit (1) and another bearing, a radial magnetic bearing (6).

15. The spinning rotor bearing system according to claim 14, characterized in that, The rotor shaft (10) supports the bearing unit (1) and the radial magnetic bearing (6).

16. A bearing unit for a spinning rotor bearing system according to any one of claims 1 to 15, characterized in that, The bearing unit (1) includes a stator having an axial first yoke (11) and a radial second yoke (12), wherein, The first yoke (11) includes a first actuator coil (21) and a first diameter (D). J1 The first opening (8) of the first yoke has a boss extending radially toward the axis of the first yoke. The second yoke (12) includes at least two second actuator coils (22a-22d) and has a second diameter (D). J2 The second opening (9) of ) and The first yoke (11) and the second yoke (12) are spaced apart from each other in the axial direction.

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