REEL FOR WINDING OR UNWINDING STRIP-SHAPED MATERIAL AND METHOD

Description

[0001] The invention relates to a reel for winding or unwinding strip-shaped material, in particular metal strip or the like, and to a method for tensioning a coil, wherein the reel comprises a frame, at least one reel head for arranging a coil for winding or unwinding material, a drive arrangement with at least one electric motor and a shaft connecting the electric motor to the reel head, wherein the electric motor is designed with a stator and with a rotor and is arranged on the frame, wherein the shaft connects the rotor directly to the reel head, wherein the rotor is mounted on the stator so as to be axially displaceable relative to the stator.

[0002] Reels of the type mentioned above are used, for example, in strip production in a rolling process, where the strip is regularly unwound from a first reel in a one-way or reversing operation with a defined strip tension, moved through a roll gap of a rolling device and wound onto another reel with a defined strip tension. Furthermore, in a subsequent rolling pass, after repeated passage through the rolling device, the strip can then be wound onto the reel once the desired rolled strip thickness has been achieved. The strip-shaped material is arranged in the form of a so-called coil on a spool or on a cardboard tube, or can be in the form of a raw bundle, which is picked up by a reel mandrel or reel head.The coil can be clamped on the reel head, which can be designed as an expanding head or a conical head, or reel heads can be provided on both sides of the coil, which hold the coil between them.

[0003] The reel head(s) are each arranged on a shaft mounted on a reel stand. The shaft is connected to an electric motor via a gearbox. Multiple electric motors can also be coupled to the gearbox to achieve different power levels. The shaft can be mounted on the reel stand so that it can be moved along a longitudinal axis of the shaft, so that the coil can be accommodated between two reel heads. The electric motor, the gearbox, optionally a coupling, and a frame to which these components are mounted thus form a reel. Such a reel is known, for example, from EP 2 896 465 B1.

[0004] In conventional reels, the strip material is wound up with a defined strip tension or a tensile force generated in the strip by the reel. This tensile force is adjusted by a control device on the reel, in particular by controlling the electric motor. For control purposes, the torque of the electric motor is calculated, from which the torque of the reel head or spool can then be determined. The torque can be determined, for example, from the power consumption of the electric motor and its current speed. However, since a gearbox, a clutch and possibly an intermediate shaft are installed between the electric motor and the reel head, the torque arriving at the reel head can be reduced, for example due to the efficiency of the gearbox.

[0005] A disadvantage of conventional reels is that, due to their design, they require a comparatively large amount of space in a production facility. Furthermore, each reel is always manufactured for a specific application and is therefore individually manufactured. The electric motor, gearbox, coupling, and reel block with reel head are always coordinated with each other, so that, for example, increasing the reel's performance with a more powerful electric motor usually requires a reinforcement of the drive train, making it hardly economically feasible.

[0006] EP 3 731 384 A1 (which forms the basis of the preamble of claim 1) shows an electric motor used to drive a reel head. The electric motor is directly connected to the reel head via a shaft, and a rotor of the electric motor can be axially displaced somewhat relative to a stator by means of a so-called actuator. The electric motor is an asynchronous motor.

[0007] US 6 293 132 B1 also discloses an electric motor with a reel head, wherein the electric motor is directly connected to the reel head via a common shaft.

[0008] EP 2 896 465 A1 concerns a reel head.

[0009] The invention is based on the object of proposing a reel and a method for tensioning a coil which enables manufacture and operation to be particularly cost-effective.

[0010] This object is achieved by a reel having the features of claim 1 and a method having the features of claim 12.

[0011] The reel according to the invention for winding or unwinding strip-shaped material, in particular metal strip or the like, comprises a frame, at least one reel head for arrangement on a reel for winding material, a drive arrangement with at least one electric motor, and a shaft connecting the electric motor to the reel head, wherein the electric motor is formed with a stator and a rotor and is arranged on the frame, wherein the electric motor is a torque motor or synchronous motor, wherein the shaft connects the rotor directly to the reel head, wherein the rotor is mounted on the stator so as to be axially displaceable relative to the stator, wherein the stator is formed from a winding package with a plurality of windings and surrounds the rotor, wherein the rotor is formed from a ring package with a plurality of rings, each with magnets on a circumference of the respective ring, wherein the rings are connected to one another,wherein, relative to a longitudinal axis of the shaft, a length of the ring package is smaller than the length of the winding package, and a displacement range of the rotor corresponds to a difference in the lengths.

[0012] Because the electric motor is a torque motor or a synchronous motor, it is possible to connect the reel head directly to the rotor via the shaft. Since the electric motor can generate a comparatively high torque, it is no longer necessary to provide a gearbox that is interposed between the electric motor and the reel stand. Furthermore, a coupling, the necessary motor bearings and the reel stand itself can be omitted. The frame or the foundation required for the frame at a production facility can thus be significantly reduced in size. In particular, the installation space for the reel and the size of the frame are then determined solely by the dimensions of the electric motor integrated into the reel stand and the reel head. Because a large part of the installation space originally required and thus the foundation can be saved, the reel can be manufactured particularly cost-effectively and operated energy-efficiently.

[0013] According to the invention, the rotor is mounted on the stator so that it can be axially displaced relative to the stator. The axial displaceability of the rotor relative to the stator can be achieved by mounting the rotor so that it can be axially displaced on the stator. The electric motor can thus be used like a prior art coiling stand. A coil can then be clamped particularly easily between two coiling heads, or a coiling head can be adapted to a length or position of a coil relative to the longitudinal axis of a shaft.

[0014] Furthermore, the rotor is formed from a ring package, which in turn is composed of a plurality of rings. Magnets are arranged on the rings on a circumference of the respective ring or in insertion pockets directly below the circumference of the ring. The size of the magnets is limited to the dimensions of the respective ring, i.e. the magnets are not arranged across rings. The rings can in turn be composed of discs or metal sheets. The rings are connected to one another directly or indirectly. For example, the rings can be screwed together, i.e. they can be detachably connected. Furthermore, the rings can also be attached directly to the shaft or arranged on a rotor carrier arranged between the shaft and an inner diameter of the rings. The stator can surround the rotor, although in principle the rotor can also surround the stator.Using multiple rings to form the rotor makes it possible to create a modular electric motor. The number of rings can always be selected to create an electric motor with the desired power output without having to modify the stator. This makes it possible to produce electric motors with different power outputs using a single stator. The production of individually designed reels can thus be standardized and thus particularly cost-effective.

[0015] The drive arrangement can be gearless. This makes the reel even more cost-effective to manufacture. In particular, a gear oil system can be omitted. Furthermore, the reel's efficiency can be improved because there are no friction losses caused by a gear. Furthermore, the reel's noise emissions are significantly reduced. Overall, the reel's maintenance effort is also lower, as it has fewer components.

[0016] According to the invention, the stator is formed from a winding package with a plurality of windings and surrounds the rotor, wherein the rotor is formed from a ring package with a plurality of rings, each with magnets on a circumference of the respective ring, wherein the rings are connected to one another, wherein, relative to a longitudinal axis of the shaft, a length LR of the ring package is formed less than the length LW of the winding package, and a displacement range V of the rotor corresponds to a difference V = LW - LR of the lengths. Consequently, the rotor can be designed as an internal rotor. The stator can be formed from a stack of ring-shaped metal sheets in which the windings are arranged in an integrated manner. The ring-shaped sheets can be surrounded by a frame that secures them. Furthermore, the frame can be formed with channels or lines through which a cooling medium flows.If the length of the ring pack is shorter than the length of the winding pack, it is possible to easily increase the power of the electric motor by adding a ring to the ring pack. The length of the winding pack can always be the same for all electric motors used to form a reel, whereby the power required by the individual electric motor for each reel can be adapted by selecting the length of the ring pack. It is advantageous to standardize the length of the stator or its winding pack. If the length of the rotor pack and the length of the winding pack are essentially the same, no more rings can be added to the electric motor. The possibility of axially displacing the rotor then arises because the length of the winding pack is greater than the length of the ring pack.The displacement range resulting from the difference in length allows the rotor to be displaced within this displacement range without such a displacement resulting in a change in the electric motor's power. This can be ensured, in particular, by ensuring that the ring core is always covered by the winding core during operation within the displacement range.

[0017] The drive arrangement can comprise two electric motors, wherein the electric motors can each have a frame and a reel head, wherein a coil can be arranged between the reel heads, wherein the respective winding packages of the electric motors can have a matching length LW. Consequently, an electric motor can be arranged on either side of the coil. If the respective winding packages of the electric motors have a matching length, the respective stator of the electric motors is essentially of the same design. The electric motors can then be essentially of the same design or have different rotors. Because the winding packages do not have to be designed differently to form electric motors of different power, the electric motors can be manufactured and maintained more easily. Costs can also be saved by producing identical stators in large quantities.Each of the electric motors can be arranged or mounted on a dedicated frame, or the electric motors can be arranged on a common frame. The coil, then arranged between the electric motors or the respective reel heads, can be moved on a carriage, which is guided, for example, on rails, transversely to a longitudinal axis of the two shafts of the electric motors. A conveyor track designed for the carriage can be arranged on a dedicated foundation.

[0018] The power of the electric motors can be different or the same. The electric motors can be operated synchronously when winding strip material. Furthermore, it can be provided to operate only one of the two electric motors if lower power is required. If the electric motors are torque motors or synchronous motors, the drive power of each electric motor can be electrically switched between two inverters as needed, allowing two or more power levels to be created for each electric motor. Depending on the total power required by the reel, the individual power outputs of the electric motors can be configured accordingly and can therefore be the same or different.

[0019] The length LR of the respective ring packs of the electric motors can vary. The length of the ring pack determines the mass of magnets on the circumference of the respective ring pack, and thus the power output of the respective electric motor. The design of electric motors with different power outputs can then be easily achieved by varying the length of the respective ring pack.

[0020] The rings can have different or identical widths. Since a ring pack is made up of a plurality of rings, it is possible to influence the length of the ring pack. This can be achieved by using a specific number of rings to create the desired length, and thus the power of the electric motor. The rings used can have the same width or different widths. If a selection of rings with different widths is available, it is possible to provide a larger number of possible ring pack lengths when designing an electric motor. A large possible variation in the length of the ring pack is already achieved if the ring pack can be put together from a number of rings with two or three different widths.

[0021] The drive arrangement can comprise a tensioning device with an actuator, wherein the rotor can be axially displaceable relative to the stator by means of the actuator. The actuator can be, for example, a hydraulically or pneumatically driven piston or a linear motor. The actuator can be coupled to the shaft of the electric motor in such a way that a movement of the actuator causes the shaft to be displaced along the longitudinal axis. Because the rotor can then be displaced relative to the stator by means of the actuator, the reel head can also be displaced along the longitudinal axis. It is then possible to arrange a coil between reel heads and to tension the coil at the reel heads or to move the reel heads into the coil and / or to create a tensioning force between the reel heads and the coil.

[0022] The rotor can be arranged on the shaft and mounted on a stator housing with radial bearings and at least one axial bearing, wherein a longitudinal guide can be formed between the bearings and the housing on either side of the rotor with respect to a longitudinal axis of the shaft. The bearings can be plain bearings and / or preferably roller bearings. The roller bearings can be deep groove ball bearings, for example, so that the bearings can absorb axial and radial forces. In this case, the radial bearing and the axial bearing can be formed by a single bearing. The longitudinal guide can be formed, for example, by a sleeve that is movable in the direction of the longitudinal axis in a bushing. However, other types of longitudinal guides can also be used. The sleeve can be part of the stator housing, and the rotor is then rotatably mounted on the sleeve with the radial bearings or the axial bearing.Preferably, such a shaft bearing can be provided on the housing on both sides of the rotor. This makes it possible for the rotor to be rotatable relative to the stator and, at the same time, to be displaceable along the longitudinal axis of the shaft together with the shaft. Such a longitudinal guide is particularly easy to design. The actuator can then also be connected to the bushing. Furthermore, it can be provided that the bushing is displaceable in the sleeve only in an axial direction. In principle, in addition to a circular sleeve or bushing, any cross-sectional shape can be provided to form such a longitudinal guide.

[0023] The drive arrangement can comprise a further actuator, by means of which the electric motor can be axially displaced relative to the frame, with respect to a longitudinal axis of the shaft, on a further longitudinal guide formed on the frame. The further actuator can be designed like the actuator and arranged on a housing of the stator or on the frame. The further actuator can then be coupled to the housing or the frame, for example, with a piston, such that a movement of the piston causes a relative movement of the frame and the housing. A further linear guide can also be formed between the housing and the frame, which enables a longitudinal displacement of the electric motor. If the drive arrangement comprises several electric motors, each of these electric motors can be designed to be longitudinally displaceable in this way.In particular, the displacement range of the electric motor can be significantly extended so that coils of different lengths can be accommodated on the reel.

[0024] The electric motor can be designed with a housing that can be attached to the frame, wherein at least one force transducer of a sensor device of a control device of the reel can be arranged between the housing and the frame. The control device can therefore be used to control and regulate the reel and in particular the strip tension of the reel, which is generated by a strip tensile force within a strip that is wound onto the spool by the reel. The electric motor, together with the rotor, creates a torque that is transmitted via the shaft to the reel head and thus to the spool. Depending on the amount of material stored on the spool, the diameter of the spool can vary greatly, so that the strip tensile force is always dependent on this diameter. A control device of the control device can be designed such that the relevant diameter is taken into account when regulating the strip tensile force.To regulate the strip tension, the shaft torque can also be regulated using the control device. This is then usually achieved by controlling the electric motor connected to the shaft. Since the electric motor is directly connected to the reel head via the shaft, without a gearbox, clutch, or the like in a drive train, it is possible to measure the torque that effectively acts on the reel head or spool at the electric motor. Due to the direct power transmission, a very precise torque measurement can be assumed. The direct power transmission enables torque measurement using the force transducer, which is located between the housing of the electric motor and the frame on which the electric motor is mounted.When the force transducer is mounted between the housing and the frame, the torque applied by the electric motor to the shaft imparts a force to the force transducer that can be measured. The sensor device or control device can then determine the shaft torque from the measured values. Only the direct connection between the electric motor and the reel head via the shaft enables this type of torque measurement and thus particularly precise control of the strip tension.

[0025] The force transducer can be designed to detect a compressive force and / or tensile force or a torque. The force transducer can be a sensor, in particular a force sensor, a load cell, or a load cell with which a force acting on the sensor can be measured. Force measurement can be carried out using a spring body, piezoelectrically, electromagnetically, electrodynamically, or electroresistively. It can be provided that electroresistive sensors, in particular strain gauges, are omitted, since these can be influenced by the magnetic field of the electric motor.

[0026] The force transducer can be arranged at a radial distance relative to a longitudinal axis of the shaft. The radial distance of the force transducer relative to the shaft can be used to easily calculate a torque from a force measured with the force transducer.

[0027] The force transducer can be designed to measure a compressive force and / or a tensile force. Depending on the direction of rotation of the shaft relative to the direction of the belt tensile force, the force transducer can be subjected to a compressive force or a tensile force. It is particularly advantageous if the force transducer can measure both a compressive force and a tensile force.

[0028] The housing can be fixed to the frame at attachment points, with a force transducer being arranged at at least one attachment point. The attachment point can be formed, for example, by a screw connection between the housing and the frame. In principle, however, the attachment point can also be a support point of the housing on the frame.

[0029] It is particularly advantageous if force transducers are installed at all mounting points. This makes it possible to measure all forces acting between the housing and the frame and thus determine the shaft torque with great precision. In principle, however, this is not necessary, since a torque can already be determined with a single force transducer if the distribution of the forces acting at the mounting points is known.

[0030] The force transducer can be arranged on a connecting flange of the housing and / or the frame. For example, the housing and the frame can each form a connecting flange, whereby the connecting flanges then abut one another and can be firmly connected via a screw connection. The force transducer can then be arranged between these connecting flanges. In this case, a preload from a screw connection can already act on the force transducer. The sensor device can be calibrated so that this preload is disregarded or does not falsify a measurement result of the force transducer. Optionally, it is also possible to arrange the force transducer on the connecting flanges so that the force transducer is not positioned between the connecting flanges, but spans the connecting flanges.For this purpose, the force transducer can then be firmly fixed to both connecting flanges so that forces acting between the connecting flanges are also transferred to the force transducer.

[0031] The drive arrangement can have two reel heads, whereby the reel heads can each be designed with an expanding head or a cone for receiving the coil. In principle, it is also possible for the drive arrangement, if it only has an electric motor, to be designed with a single expanding head. The expanding head can be designed such that it can be inserted into an opening at one end of a coil. Segments of the expanding head can then be clamped against an internal tension of the coil so that the coil is firmly fixed to the expanding head and centered. The movement of the segments can be effected, for example, hydraulically or by means of a pull rod. The cone can be designed such that it rests on one end of the coil so that the coil is clamped between two reel heads that can be moved against each other. Here, too, the coil is centered relative to the reel head.

[0032] The expansion head can have an expansion segment arrangement comprising expansion segments designed for radial tensioning of the coil. At least one hydraulic line or a pull rod for actuating the expansion segments can be arranged within the shaft. The shaft can therefore be designed as a hollow shaft or a solid shaft. In principle, it is also possible to connect the expansion head directly, i.e., to a hydraulic or mechanical actuator on the expansion head itself, so that the shaft is unaffected.

[0033] A modular system for forming a reel according to the invention comprises a stator formed from a winding package with a plurality of windings or winding heads and a plurality of rings, each with magnets on a circumference of the respective ring or in insertion pockets directly below the circumference of the ring, which serve to form a ring package of a rotor, wherein the rings are selected from a first set of rings with a first width and a second set of rings with a second width, which can differ from the first width. The modular system enables the formation of ring packages with different lengths LR, so that electric motors with different power outputs can be assembled from these ring packages or the modular systems. By having different sets of rings available for selection, a high level of variability can be achieved while at the same time significantly reducing costs.The production of rotors and electric motors can thus be standardized to a high degree and is therefore particularly cost-effective.

[0034] In the method according to the invention for tensioning a spool for winding or unwinding strip-shaped material, in particular metal strip or the like, using a reel according to the invention, a rotor on at least one electric motor of a drive arrangement of the reel is axially displaced relative to a stator of the electric motor by means of a tensioning device of the drive arrangement, such that the spool arranged between reel heads of the drive arrangement is tensioned or released, wherein the electric motor is a torque motor or synchronous motor. For the advantageous effects of the method, reference is made to the description of the advantages of the reel according to the invention.

[0035] The axial displacement can be used for strip centering and / or strip centering before or during rolling operations. Strip centering is used to unwind the strip from a coil that is not wound with a straight edge during rolling and to guide it centrally through a roll gap, so that it is then wound with a straight edge onto a spool. Strip centering is used to center a coil that is not wound with a straight edge in a rolling line before rolling, so that the wound strip is guided centrally through the roll gap. The position of the strip can be determined using sensors. Data from the sensors can be used for control and thus for axial displacement.

[0036] To carry out the method according to the invention, a reel according to the invention is used. Further advantageous embodiments of the method emerge from the descriptions of the features of the subclaims referring back to device claim 1.

[0037] A preferred embodiment of the reel is explained in more detail below with reference to the drawings.

[0038] They show: Fig. 1 A first embodiment of a reel in a longitudinal sectional view; Fig. 2 a second embodiment of a reel in a longitudinal sectional view; Fig. 3 a third embodiment of a reel in a longitudinal sectional view; Fig. 4 a fourth embodiment of a reel in a longitudinal section.

[0039] The Fig. 1 shows a reel 10 for winding strip-shaped material 11 or a metal strip onto a spool 12. The reel 10 here comprises two essentially identically designed frames 13, two identically designed reel heads 14 for arranging the spool 12, and a drive arrangement 15, which in turn comprises two identically designed electric motors 16 or torque motors. Each of the electric motors 16 is formed from a stator 17 and a rotor 18, wherein the stator 17 surrounds the rotor 18 and the rotor 18 is rotatably mounted within the stator 17. The rotor 18 is arranged in a rotationally fixed manner by means of a rotor carrier 19 directly on a shaft 20 of the electric motor 16, wherein the shaft 20 is in turn directly connected to the reel head 14. The rotor 18 is further formed from a ring package 21 comprising a plurality of rings (not shown in detail here), each with magnets on a circumference 22 of the respective ring.These rings are detachably connected to one another. The stator 17 is formed from a winding package 23 with a plurality of windings (not shown in detail here), which are surrounded by a frame (not shown in detail here). Cooling channels 24 are formed within this frame, through which a cooling medium (not shown here) flows and serve to cool the winding package 23. Passive cooling or surface cooling of the frame is also possible.

[0040] The electric motor 16 is further formed with a housing 25, which surrounds the rotor 18 and the stator 17. The housing 25 is firmly connected or screwed to the frame 13 at fastening points 26. The frame 13, in turn, is firmly connected to a foundation 28 at fastening points 27. Furthermore, the housing 25 is formed with a longitudinal guide 29, which allows axial displacement of the rotor 18 relative to the stator along a longitudinal axis 30 of the shaft 20. The longitudinal guide 29 is formed from sleeves 31 and 32, which are arranged on either side of the rotor 18, and bushings 33 and 34, respectively, surrounding the sleeves 31 and 32. The shaft 20 is radially and axially mounted within the sleeves 31 and 32 by means of rolling bearings 35. A displacement of the rotor 18 relative to the stator is possible within a displacement range V, wherein the displacement range V results from a difference between a length LR of the ring package 21 and a length LW of the winding package 23.A possible displacement is achieved by means of an actuator 36, which here is formed by a hydraulic cylinder 37 and is coupled to the bushing 33 via a strut 38. The possibility of displacing the rotor 18 or the shaft 20 with the reel head 14 thus creates a tensioning device 39 for tensioning the coil 12 between the reel heads 14.

[0041] In particular, the direct drive of the coil 12 by the electric motors 16 makes it possible to significantly reduce the number of rotating parts of the reel 10 and to dispense with additional drive shafts, couplings, or the like. A mechanical brake as a service brake on the reel can also be dispensed with, since the electric motors 16 can be braked via a short circuit of the windings via a resistor in the event of a power failure or a converter malfunction. Furthermore, a standstill brake can be omitted, since the rotor can be held in position by short circuiting the windings when the rotor is stationary. By reducing the number of parts or assemblies of the reel 10, maintenance costs can be significantly reduced.

[0042] Furthermore, it is possible to adjust the power of the electric motors 16 by adding rings even after the reel 10 has already been put into operation or to increase the power.

[0043] The drive assembly 15 comprises a further actuator 40, which is arranged on the frame 13 and is formed by a further hydraulic cylinder 41. The housing 25 is mounted on a further longitudinal guide 42, which is formed on the frame 13, and is also axially displaceable in the longitudinal direction of the longitudinal axis by means of the further actuator 40.

[0044] The reel heads 14 are each designed as an expansion head 43, which has expansion segments (not shown here) that can be actuated via a hydraulic line (also not shown). The expansion segments can exert a clamping force on an inner side 44 of the coil 12, so that the coil 12 is centered on the respective expansion heads 43 and clamped in a rotationally fixed manner. The coil 12 with the material 11 can be transported to the reel 10 by means of a carriage 45, which is movable on rails 46 transversely to the longitudinal axis 30.

[0045] Furthermore, force transducers 47 are arranged on the housing 25 or the fastening points 26 between the housing 25 and the frame 13. The force transducers 47 are a component of a control device not shown in detail here. The control device serves to regulate a strip tension or a strip tensile force of the reel 10 or a power and thus a torque of the electric motors 16. The control device comprises a control device for regulating the strip tensile force or the electric motors 16 and a sensor device, which in turn comprises the force transducers 47. Because the force transducers 47 are arranged between the frame 13 and the housing 25, it is possible to determine the forces acting between the frame 13 and the housing 25.Since the electric motors 16 are each directly connected to the reel 12 via the shaft 20 and the reel head 14, a torque of the respective electric motor 16 can be determined directly and thus particularly accurately via the force transducers 47 or the sensor device, which enables improved control of the strip tensile force.

[0046] The Fig. 2 shows a reel 48, in which, in contrast to the reel from the Fig. 1 a frame 49 is designed without any further longitudinal guide. Tensioning of a coil 50 is already possible here by the tensioning device 39.

[0047] The Fig. 3 shows a reel 51, in which, in contrast to the reel from the Fig. 2 Reel heads 52 are provided, which form a cone 53 for receiving a coil 54. The coil 54 is formed with an inner cone 56 at its respective ends 55. The coil 54 can be held centered and non-rotatably on the reel 48 by clamping it between the reel heads 52.

[0048] The Fig. 4 shows a reel 57, in contrast to the reel from the Fig. 1 a frame 13 and an electric motor 16 are provided. Instead of an additional electric motor, a counterbearing 58 is provided here. A spreading drum 59 for receiving a coil 60 or raw coil is attached to the shaft 20 of the electric motor 16. In the case of a raw coil, the material 11 is placed directly on the spreading drum 59 without the coil 60.

Claims

1. A reel (10, 48, 51, 57) for winding or unwinding strip-shaped material (11), in particular a metal strip or the like, the reel comprising a frame (13, 49), at least one reel head (14, 52) for disposing a coil (12, 50, 54) for winding or unwinding material, a drive arrangement (15) having at least one electric motor (16), and a shaft (20) which connects the electric motor to the reel head, the electric motor being formed comprising a stator (17) and a rotor (18) and being disposed on the frame, the shaft connecting the rotor directly to the reel head, the rotor being mounted on the stator so as to be axially displaceable relative to the stator characterized in that the electric motor is a torque motor or a synchronous motor, the stator (17) being formed from a coil package (23) having a plurality of coils and surrounding the rotor (18), the rotor being formed from a ring package (21) having a plurality of rings, each having magnets on a circumference (22) of the respective ring, the rings being connected to each other, a length (LR) of the ring package being smaller than the length (LW) of the coil package relative to a longitudinal axis (30) of the shaft (20), and a displacement range (V) of the rotor corresponding to a difference of the lengths (LW, LR).

2. The reel according to claim 1, characterized in that the drive arrangement (15) comprises two electric motors (16), the electric motors each comprising a frame (13, 49) and a reel head (14, 52), a coil (12, 50, 54) being disposed between the reel heads, the respective coil packages (23) of the electric motors having a corresponding length (LW).

3. The reel according to claim 2, characterized in that a power of the electric motors (16) differs or is the same in size.

4. The reel according to claim 3, characterized in that a length (LR) of the respective ring packages (21) of the electric motors (16) is different.

5. The reel according to any one of the claims 1 to 4, characterized in that the rings differ from each other in width or are identical in width.

6. The reel according to any one of the preceding claims, characterized in that the drive arrangement (15) comprises a tensioning device (39) having an actuator (36), the rotor (18) being axially displaceable relative to the stator (17) by means of the actuator.

7. The reel according to claim 6, characterized in that the rotor (18) is disposed on the shaft (20) and mounted on a housing (25) of the stator (17) by means of radial bearings and at least one axial bearing, a longitudinal guide (29) being formed between each of the bearings (35) and the housing on either side of the rotor relative to a longitudinal axis (30) of the shaft.

8. The reel according to claim 6 or 7, characterized in that the drive arrangement (15) comprises an additional actuator (40) by means of which the electric motor (16) is axially displaceable on an additional longitudinal guide, which is formed on the frame, relative to the frame (13, 49) with respect to a longitudinal axis (30) of the shaft (20).

9. The reel according to any one of the preceding claims, characterized in that the electric motor (16) is formed having a housing (25) which is attached to the frame (13, 49), at least one force transducer (47) of a sensing device of a control device of the reel (10, 48, 51, 57) being disposed between the housing and the frame.

10. The reel according to any one of the preceding claims, characterized in that the drive arrangement (15) has two reel heads (14, 52), each reel head being formed so as to have an expansion head (43) or a cone (53) for receiving the coil (12, 50, 54).

11. The reel according to claim 10, characterized in that the expansion head (43) has an expansion-segment arrangement which has expansion segments and which is formed for radially tensioning the coil (12, 50), at least one hydraulic line being formed or a drawbar for actuating the expansion segments being disposed within the shaft (20).

12. A method for tensioning a coil (12, 50, 54, 60) for winding or unwinding strip-shaped material (11), in particular a metal strip or the like, by means of a reel (10, 48, 51, 57) according to any one of the claims 1 to 11, characterized in that a rotor (18) is axially displaced relative to a stator (17) of the electric motor on at least one electric motor (16) of a drive arrangement (15) of the reel by means of a tensioning device (39) of the drive arrangement in such a manner that the coil, which is disposed between reel heads (14, 52) of the drive arrangement, is tensioned or released, the electric motor being a torque motor or a synchronous motor.

13. The method according to claim 12, characterized in that the axial displacement is used for a strip center control and / or a strip center alignment before or during a rolling operation.