Ring for ring spinning machine or ring twisting machine

Abstract

The invention relates to a driven ring for a ring spinning machine or a ring twister, having an electric drive (11) with a stator (12) and a rotor (13) with magnets (17), wherein the ring comprises a ring crown (15) for abutting against a ring traveler (10) and a connecting section (16), and the ring is connected to the rotor (13) of the drive (11) via the connecting section (16) in a rotationally fixed manner. The drive (11) has a coil system for generating a torque and a radial force, wherein one axial degree of freedom (26) and two tilting degrees of freedom (27, 28) of the rotor (13) are passively stabilized by means of a magnetoresistive force, and two radial degrees of freedom (29, 30) are actively stabilized by means of a control loop.

Description

Technical Field

[0001] This invention relates to a ring for use in a ring spinning machine or a ring twisting machine. Background Technology

[0002] Rings, also known as spinning rings, are used in so-called ring spinning machines or as twisting rings in so-called twisting machines. Here, the ring or twisting ring works in conjunction with a ringläufern (a type of traveler). The traveler, dragged by the thread held by the traveler, rotates at high speed on the upper side of the ring, the so-called ringkrone, resulting in a high load on the contact surface between the traveler and the ringkrone. To secure the ring or twisting ring in the machine, a web is provided, which may end in a foot flange. The ringkrone and the foot flange, or in the absence of a foot flange and the web, are manufactured in various embodiments, each tailored to the shape and geometry required by the machine and the structure of the fasteners provided for the ring or twisting ring. The ring is held in the machine in a so-called ringrahmen. Hereinafter, the terms ring and twisting ring are collectively referred to as ring.

[0003] During operation, the frictional surfaces between the ring and the traveler generate heat, and consequently, the yarn also heats up. The rapid rotation of the traveler on the ring can cause localized temperatures exceeding 400°C, setting operational limits for the traveler-ring system. Due to these mechanical conditions, the traveler's rotational speed cannot exceed 30,000 revolutions per minute, otherwise damage to the traveler or yarn may occur. In the prior art, attempts have been made to remedy this situation by using a rotating ring. By using a rotating ring, the relative speed between the traveler and the ring can be reduced, and therefore, compared to a fixed ring, the traveler's rotational speed can be increased without increasing the thermal load on the traveler-ring system. Increasing the traveler's rotational speed can also correspondingly increase the spinning machine's output. Different embodiments of the traveler-ring system with a rotating ring are known from the prior art. For example, CN 109 763220 A describes a ring drive with a hollow shaft motor. Here, the hollow shaft of the motor, fastened to a ring seat, is non-rotatably connected to the ring. The traveler is either held freely in rotation on the ring crown or held in a fixed position on the ring crown. Furthermore, utility model CN ​​208 266 341 U discloses a driven ring in which the ring is connected to the rotor of an electric motor, and the stator of the electric motor is secured to a ring bank via the motor housing. CN108 301 078 A discloses a driven ring-travel system that should achieve “high-speed operation” of the spinning machine and should improve the traveler’s lifespan by reducing the relative speed between the ring and the traveler. An assembly for a traveler-ring system includes a ring for supporting the traveler, wherein the ring is mounted on the rotor of a driver. The rotor is held in an outer ring by means of ball bearings, which is secured to a ring bank.

[0004] A disadvantage of known implementations of driven steel rings is their support mechanism. Roller bearings or similar structures are used to stabilize the steel ring in the radial direction. However, the mechanical support mechanism generates heat, and the mechanical properties of the mating materials in the mechanical bearings limit the rotational speed. Summary of the Invention

[0005] The objective of this invention is to provide a driven ring in which the possibility of increasing rotational speed is not hindered by mechanically generated frictional heat.

[0006] This task is accomplished by a driven ring used in ring spinning machines or ring twisting machines.

[0007] To address this task, a novel drive for a ring in a ring spinning machine or ring twisting machine is proposed, comprising an electric drive having a stator and a rotor with magnets. The ring includes a crown for abutting a traveler and a connecting section, and the ring is non-rotatably connected to the rotor of the drive via the connecting section. The drive has a coil system for generating torque and radial force, wherein one axial degree of freedom and two tilting degrees of freedom of the rotor are passively stabilized by magnetic resistance, and the two radial degrees of freedom are actively stabilized by an adjustment loop. Drives with coil systems capable of generating torque and radial force are known in the prior art and are referred to in the literature as bearingless motors.

[0008] A magnet firmly connected to the rotor generates an excitation magnetic field. Three degrees of freedom are passively stabilized by this magnetic field, that is, without energizing the coils. These are the axial degree of freedom and two tilting degrees of freedom. The two radial degrees of freedom are stabilized by appropriately energizing a given sub-coil. In this adjustment, the energizing is adjusted not only according to the rotor's radial position but also according to the rotor's electrical rotation angle. The rotor's radial position (x and y directions) and electrical rotation angle are continuously detected by sensors. The required coil current is determined in this adjustment to move the rotor into its unloaded pose in the xy-plane. The current generated by this adjustment is called the force-current component. The average value of the force-current component is approximately 0 amperes because the rotor is held in its unloaded pose by the adjustment. In addition to the force-current component, a torque-current component is also applied to the coils. This current component corresponds to the current used by the synchronous motor during its operation. Therefore, all manipulation methods known from the field of synchronous motors, such as achieving higher speeds through field weakening, are feasible in bearingless motors.

[0009] Bearingless motors can be implemented with four or fewer strands. Each strand can be implemented by series and / or parallel connection of coils, as is common in motor technology. The individual coils can be arranged concentrically around the pole shoes, or implemented as distributed windings.

[0010] Figure 9 illustrates an embodiment with 5 strands and 5 concentric coils. Each coil, as described, has two current components: a force-current component for radially supporting the rotor and a torque-current component for driving and braking the rotor. Figure 10 An alternative implementation is shown. Here, there is only one coil for the force-current component and for the torque-current component. Compared to Figure 9, the disadvantage of this implementation is that it requires multiple electronic components (typically power semiconductors) to control the coil.

[0011] Advantageously, the drive is constructed as a bearingless disc rotor system (Scheibenläufer) with a flat stator, and the ratio of the axial length of the rotor magnet to its diameter is less than 0.4. The data for axial length and diameter pertain to the rotor magnet, not the external dimensions of the entire rotor structure. The geometric variable that decisively affects the passive stability of the rotor is the axial length, or the ratio of the axial length to the diameter of the rotor disc or its magnet. Since changes in axial length also alter the maximum air gap flux of the pole pitch, changes in length also affect the degrees of freedom for active stabilization, namely load capacity and motor torque. Here, only the amplitudes of the force and torque are changed, not their orientation depending on the rotor angle. For this reason, variations in axial length must be considered in the design of bearings and motors regarding the magnitude of achievable forces and torques. For passive stability of the rotor's axial and tilting movements, the preferred ratio of the rotor magnet's axial length to its diameter is 0.3, or expressed as the reciprocal of the diameter to the length of 3.

[0012] In an alternative embodiment of a bearingless disc rotor system with a flat stator, the drive is configured as a bearingless disc rotor system with a temple configuration, wherein, in this embodiment, the ratio of the axial length of the rotor magnet to the diameter of the rotor magnet is less than 0.4. In this case, the axial length and diameter data also refer to the rotor magnet, not the external dimensions of the entire rotor structure. The advantage of a drive with a temple configuration stator is that the entire drive has a smaller external diameter than a disc rotor system with a flat stator. This results in less space requirement between the individual drives installed in the ring spinning machine, allowing for closer assembly of the spinning positions, and enabling the addition of rings according to the invention to existing machines, for example.

[0013] Preferably, the wire traveler is configured to move freely against the ring crown. In this embodiment, the wire traveler is dragged along the ring crown by yarn. With the driven ring, the maximum speed difference between the ring crown and the wire traveler can now be maintained, although the wire traveler can run at a much higher speed relative to the ring frame than existing rings.

[0014] In an alternative embodiment of the freely movable traveler, the traveler is positioned fixedly against the ring crown. In this embodiment, the traveler is not dragged by the yarn independently of the movement of the ring crown. The rotation of the traveler is determined solely by the rotation of the rotor of the ring and therefore the drive. In a preferred embodiment, the traveler and the ring crown are constructed as a single unit.

[0015] Advantageously, an additional active magnetic bearing can be installed to stabilize the rotor's axial degree of freedom. With an active axial magnetic bearing, the stiffness and damping associated with axial vibration can be adjusted. This improves the stability of axial vibration, that is, reduces the maximum axial deviation of the rotor. Furthermore, the rotor can be held in a defined axial position. The magnetic bearing contains corresponding sensors to enable active adjustment of the axial position.

[0016] Preferably, damping of tilting vibrations is provided by means of a compensating device, wherein the compensating device has at least one electrical conductor loop separated from the winding. The application of such a compensating device is known from the disclosure of EP 3 255 760 A1. Here, the electrical conductor loop separated from the winding is not linked to the excitation magnetic field chain in the reference position of the rotational axis on the one hand, and is linked to the excitation magnetic field chain in the actual position of the rotational axis tilted relative to the reference position on the other hand, to counteract the effects of tilting. This mode of operation corresponds to the effect of an electric damper, with the particular advantage that the damping effect increases with increasing rotational speed.

[0017] An emergency bearing is advantageously positioned, consisting of at least one sliding ring fastened to the stator. The emergency bearing is made of a material with sliding properties, such as PTFE, and is used to hold the rotor in the correct position when the drive is de-energized. If the force acting on the rotor is higher than the force of the magnetic bearing, the emergency bearing ensures that the rotor remains within the stator. For this reason, the emergency bearing is typically positioned not only radially but also axially. In the event of a power outage, the DC voltage intermediate circuit typically continues to supply power through regeneration, i.e., targeted braking of the rotor, which also allows the active radial magnetic bearing to continue functioning properly. If the rotor speed falls below a defined limiting speed, regeneration is no longer possible, and the rotor falls into the radial emergency bearing.

[0018] Only specific combinations of the number of rotor magnet poles and the number of stator strands are suitable for operation as a bearingless motor. The minimum number of strands is 4. With a strand count ranging from 4 to 6 and a pole count ranging from 2 to 10, the following implementation schemes are possible:

[0019] - 4 strands / 4 poles

[0020] - 5 strands / 2 poles

[0021] - 5 strands / 6 poles

[0022] - 4 strands / 4 poles

[0023] - 6 strands / 2 poles

[0024] - 6 strands / 6 poles

[0025] - 6 strands / 8 poles

[0026] If the number of strands corresponds to the number of poles, the motor has single-phase characteristics. This means that at a specific motor rotation angle, the motor torque becomes zero. However, this characteristic does not fundamentally preclude the application of this topology.

[0027] If the extreme number divided by 2 is even, then the compensation device described in EP 3 255 760 A1 will not work.

[0028] It has been found that it is advantageous if the rotor magnets have 6 poles and the stator has 4 to 6 strands. In an alternative embodiment, the rotor magnets have 4 poles and the stator has 4 strands.

[0029] A ring spinning machine with a ring seat is also proposed, having at least one driven ring fastened to the ring seat as described above. Here, the stator is fastened to the ring seat, for example by clamping or tightening. An opening for the spindle is correspondingly provided in the ring seat, which is concentric with the opening of the rotor. To accurately position the drive or ring, a measuring tool or a positioning aid mounted on the ring seat can be used.

[0030] Advantageously, the damping of the driven ring's support device is provided by damping elements made of viscoelastic material in the fasteners of the stator on the ring seat. The advantage of arranging the damping in the fasteners is that, on the one hand, rotor vibrations transmitted to the stator are converted into heat in the damping elements, and on the other hand, external vibrations are not transmitted to the rotor. Typically, damping elements made of butyl rubber are used here.

[0031] Similarly, protection is claimed for a ring twisting machine having at least one driven ring as described above. Attached Figure Description

[0032] The invention is explained in detail below with reference to the drawings, wherein:

[0033] Figure 1 A schematic diagram of a ring spinning machine is shown;

[0034] Figure 2 A schematic diagram of a driven steel collar according to the invention in a first embodiment is shown;

[0035] Figure 3 It shows that in accordance with Figure 2 A schematic cross-sectional view of part XX in the implementation method;

[0036] Figure 4 A schematic diagram of a driven steel collar according to the invention in a second embodiment is shown;

[0037] Figure 5 A schematic diagram of the fasteners on the ring seat of the driven steel collar is shown;

[0038] Figure 6a , 6b A schematic diagram of a disc rotor system with a flat stator in a first embodiment is shown.

[0039] Figure 7a , 7b A schematic diagram of a disc rotor system with a temple configuration is shown.

[0040] Figure 8 A schematic diagram of the degrees of freedom is shown;

[0041] Figure 9a , 9b A schematic diagram of the disc rotor system in the second embodiment is shown;

[0042] Figure 10 A schematic diagram of the disc rotor system in the third embodiment is shown. Detailed Implementation

[0043] Figure 1 The schematic diagram shows the spinning positions of a ring spinning machine, where modern ring spinning machines have up to 2000 such spinning positions. In the ring spinning machine, a fiber bundle, called a fiber sliver 1, is supplied to the drafting mechanism 2. The fiber sliver 1 is drafted into a thread 3 by the drafting mechanism 2. The drafting mechanism 2 shown is a so-called apron drafting mechanism, commonly used for cotton. Many structural types of drafting mechanisms 2 are known from the prior art, depending on the application. After the drafting mechanism 2, the thread 3 is guided to a traveler 10 via a guide wire 4. After passing the traveler 10, the thread 3 is wound onto a bobbin 5. The bobbin 5 is placed in a rotation 6 by a drive 7. The rotation 6 of the bobbin 5 carries the traveler 10 through the thread 3, which results in the thread 3 being twisted and thus forming yarn. By holding the traveler 10 on a ring 8, the traveler 10 is forced to wrap around the bobbin 5. The ring 8 is fixedly held on a ring seat 9.

[0044] Figure 2 A schematic diagram of the driven ring according to the invention in the first embodiment is shown in the top view. Figure 3 It shows according to Figure 2 A schematic cross-sectional view of part XX in the embodiment. The stator 12 is fastened to the ring bank 9 using fasteners 18. The exemplary stator 12 has a square shape and is fixedly held to the ring bank 9 at each corner using fasteners 18 in the form of screws. One possible embodiment of the fastener is shown in... Figure 5As shown in the diagram. A rotor 13 is arranged within a stator 12, wherein the stator 12 and rotor 13 together form a drive 11. A magnet 17 is connected to the rotor. The rotor 13 or its magnet 17 has an axial length L and a diameter D. The magnet 17 has, for example, 4, 6, or 8 poles. The magnet 17 can be implemented as a single ring or formed by segments. The stator 12 and rotor 13 are arranged concentrically about the axis of rotation 14 of the steel ring 8. The steel ring 8 is also arranged concentrically with the drive 11 and is fixedly fastened to the rotor 13 via a connecting section 16. The steel ring 8 has a ring crown 15 on which a wire coil 10 is movably abutted.

[0045] Figure 4 A schematic diagram of the driven ring according to the invention in a second embodiment is shown. A rotor 13 with magnet 17 and a stator 12 arranged around the rotor 13 are shown. A steel ring 8 is constructed on the rotor, having a ring crown 15 and a connecting section 16. The steel ring 8 is fixedly connected to the rotor 13 via the connecting section 16. A wire coil 10 is fixedly fastened to the same position on the ring crown 15. Thus, the rotor 13 is placed in rotation, and the steel ring 8 and the wire coil 10 fastened thereto are also placed in rotation via the rotor 13. Figure 3 Unlike the illustrations, the wire ring 10 cannot move freely on the ring crown 15, but always has the same rotational speed as the wire ring 8 or the rotor 13.

[0046] A distance sensor 22 is embedded in the stator 12 for adjusting the active radial magnetic bearing. Similarly, an emergency bearing 20 is fastened to the stator 12, partially surrounding and abutting the fitted rotor 13 in a ring-like manner. The emergency bearing 20 functions both radially and axially. Additionally, an additional axial magnetic bearing 31 with an attached axial distance sensor 21 is shown. A compensation device 19 in the form of a conductor circuit is embedded in the stator 12.

[0047] Figure 5 A schematic diagram of the fasteners on the ring seat 9 of the driven ring is shown. Here, the stator 12, equipped with the compensation device 19 and the radial distance sensor 22, has a through opening, and the ring seat 9 has a correspondingly arranged internal thread. The through opening has an increased diameter at both ends for receiving the damping device 23. The damping device 23 disengages the stator 12 from the ring seat 9 on the one hand, and from the fastener 18 on the other. The fastener 18 is exemplarily represented by a screw. In the case of the screw in the illustrated embodiment, it is necessary to install the damping device 23 at both ends of the screw, because otherwise vibration would be transmitted from the ring seat 9 to the stator 12 via the screw body (or vice versa).

[0048] Figure 6a and 6bA schematic diagram of a so-called bearingless disc rotor system in the first embodiment is shown. A top view and cross-section of the disc rotor system with a flat stator 12 are shown. A rotor 13 is arranged within the stator 12, and its magnets 17 have an axial length L and a diameter D. The rotor 13 and stator 12 are arranged concentrically about a rotation axis 14. Magnets 17 are schematically shown on the rotor 13, where the number of poles is not shown. The stator 12 is shown as a lamination with five-strand windings 24 facing the rotor 13.

[0049] Figure 7a and 7b A schematic diagram of a disc rotor system with a stator 12 having a temple configuration is shown. A top view and cross-section of the disc rotor system are shown. The structural form of the rotor 13, with its magnets 17 and its axial length L and diameter D, corresponds to that of... Figure 6a and 6b The rotor 13. In this embodiment, the stator 12 and the rotor 13 are also arranged concentrically about the axis of rotation 14. However, the stator 12 has a larger axial extension than the rotor 13, so that the winding 24 shown here as six strands is arranged to be axially displaced along the axis of rotation 14 of the rotor 13.

[0050] Figure 8 A schematic diagram of the degrees of freedom is shown. For simplicity, rotor 13 is shown as a cylindrical ring. Rotation of rotor 13 about rotational axis 14 is shown, and rotational degree of freedom 25 is marked here. However, for... Figure 8 All direction markings apply, including those for the opposite direction. Additionally, two tilt degrees of freedom (27 and 28), one axial degree of freedom (26), and two radial degrees of freedom (29 and 30) are marked.

[0051] Figure 9a and 9b A schematic diagram of a disc rotor system in a second embodiment is shown. A top view and cross-section of the disc rotor system are shown. A rotor 13 is arranged within a stator 12, and its magnet 17 has an axial length L and a diameter D. Steel rings 8 are fastened to the rotor 13. The rotor 13 and stator 12 are arranged concentrically about a rotation axis 14. Four fasteners 18 are provided on the stator 12. The magnet 17 is schematically shown on the rotor 13, where the number of poles is six, visible in the top view. The stator 12 has five teeth 34, on which a winding 24 is mounted, resulting in five strands.

[0052] Figure 10A schematic diagram of the disc rotor system in the third embodiment is shown in a top view. The rotor 13 is arranged within the stator 12. The rotor 13 and stator 12 are arranged concentrically. Four fasteners 18 are provided on the stator 12. Magnets 17 are schematically shown on the rotor 13, where the number of poles is six, visible in the top view. The stator 12 has five teeth 34, resulting in five strands. Windings in the form of coils are mounted on the teeth, wherein each inner coil on the tooth 34 is configured as a radial force coil 32 and each outer coil on the tooth 34 is configured as a torque coil 33.

[0053] List of reference numerals

[0054] 1. Fiber strip

[0055] 2. Drafting mechanism

[0056] 3 lines

[0057] 4. Conductor

[0058] 5 yarn tubes

[0059] 6. Rotation of the yarn tube

[0060] 7 drives

[0061] 8 steel collar

[0062] 9 rings

[0063] 10 Steel wire rings

[0064] 11 drives

[0065] 12 stators

[0066] 13 Rotors

[0067] 14. The axis of rotation of the steel ring

[0068] 15 Ring Crown

[0069] 16 Connecting Sections

[0070] 17 Magnets

[0071] 18 Fasteners

[0072] 19 Compensation device

[0073] 20 Emergency Bearings

[0074] 21 Axial Distance Sensor

[0075] 22 Radial path sensor

[0076] 23 Damping elements

[0077] 24 windings

[0078] 25 rotational degrees of freedom

[0079] 26 axial degrees of freedom

[0080] 27 tilting degrees of freedom

[0081] 28 tilting degrees of freedom

[0082] 29 radial degrees of freedom

[0083] 30 radial degrees of freedom

[0084] 31 Axial magnetic bearing

[0085] 32 Radial force coil

[0086] 33 Torque Coil

[0087] 34 Stator teeth

[0088] D Rotor diameter

[0089] L is the axial length of the rotor.

Claims

1. A driven ring for a ring spinning machine or ring twisting machine, having an electrically driven actuator (11) having a stator (12) and a rotor (13) with magnets (17), wherein, The ring includes a crown (15) for abutting the wire coil (10) and a connecting section (16), and the ring is non-rotatably connected to the rotor (13) of the driver (11) via the connecting section (16). The driver (11) is characterized by having a coil system for generating torque and radial force, wherein one axial degree of freedom (26) and two tilting degrees of freedom (27, 28) of the rotor (13) are passively stabilized by magnetic resistance, and two radial degrees of freedom (29, 30) are actively stabilized by an adjustment loop. An emergency bearing (20) is provided, wherein the emergency bearing (20) is formed by at least one sliding ring fastened to the stator (12). The emergency bearing (20) partially surrounds and embeds the rotor (13), and the emergency bearing functions in both the radial and axial directions.

2. The ring according to claim 1, characterized in that, The drive is configured as a bearingless disc rotor system with a flat stator (12), and the ratio of the axial length (L) of the magnet (17) to the diameter (D) of the magnet (17) is less than 0.

4.

3. The ring according to claim 1, characterized in that, The drive is configured as a bearingless disc rotor system with a stator (12) having a temple configuration, and the ratio of the axial length (L) of the magnet (17) to the diameter (D) of the magnet (17) is less than 0.

4.

4. The ring according to any one of claims 1 to 3, characterized in that, The wire ring (10) is configured to move freely and rest against the ring crown (15).

5. The ring according to any one of claims 1 to 3, characterized in that, The wire ring (10) is positioned to be fixedly attached to the ring crown (15).

6. The ring according to claim 5, characterized in that, The wire ring (10) and the annular crown (15) are constructed as a single unit.

7. The ring according to any one of claims 1 to 3, characterized in that, An additional active magnetic bearing (31) is provided to stabilize the axial degree of freedom (26) of the rotor (13).

8. The ring according to any one of claims 1 to 3, characterized in that, Damping of tilting vibrations is provided by means of a compensation device (19), wherein the compensation device (19) has at least one electrical conductor loop that is separate from the winding.

9. The ring according to any one of claims 1 to 3, characterized in that, The rotor (13) has a magnet (17) with 6 poles and the stator (12) has 5 strands.

10. The ring according to any one of claims 1 to 3, characterized in that, The rotor (13) has magnets (17) with 6 poles and the stator (12) has 4 to 6 strands.

11. The ring according to any one of claims 1 to 3, characterized in that, The rotor (13) has a magnet (17) with 4 poles and the stator (12) has 4 strands.

12. A ring spinning machine having a ring seat (9) and at least one driven ring fastened to the ring seat (9) according to any one of claims 1 to 11.

13. The ring spinning machine according to claim 12, characterized in that, The damping of the bearing of the driven ring is provided by a damping element (23) made of viscoelastic material in the fastener (18) of the stator (12) on the ring seat (9).

14. A ring twisting machine having at least one driven ring according to any one of claims 1 to 11.

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