EP3277449B1 - Forging hammer with electric linear drive - Google Patents

Description

The underlying invention relates to a forging hammer with an electric linear drive.

A forging hammer with linear drive is for example from the DE 20 2008 018 169 U1 known, which forms the basis for the preamble of claim 1. In the known forging hammer, a hammerbeard is designed as a linear rotor of a linear motor and has magnets or secondary parts attached to it, which are held longitudinally displaceably together with the hammerbeard in a stationary primary part. In order to carry out forging movements, the hammerbear, which is designed as a linear runner, is moved up and down by operating the linear motor accordingly, so that forging operations can be carried out at the base of the downward movement.

The well-known forging hammer leaves room for improvements and variations with regard to the design and layout of the linear drive and hammer head.

U.S. 3,709,083 A discloses an electrically powered punch press. In this known punch press, a tool holder that holds a tool is driven by a piston of an electric linear drive. The piston has a spherically designed end which, during a pressing stroke, interacts loosely with a concave recess in a plate screwed onto the tool holder. For the return stroke of the tool holder after the press stroke, return springs are provided which are tensioned during the press stroke and whose spring energy causes the tool holder to be returned during the return stroke.

In this respect, an object of the present invention can be seen in developing the known forging hammer, in particular specifying alternative and / or improved embodiments of a forging hammer with a linear drive.

According to the invention, this object is achieved in particular by the features of claim 1. Further solutions, configurations and variants of the invention emerge in particular from the dependent claims and from the following description of exemplary embodiments.

In embodiments according to patent claim 1, a forging hammer is provided which comprises an electrical, in particular electromagnetic, linear drive with a linear rotor and a hammer or hammer-hammer coupled to this, i.e. the linear rotor, for the purpose of executing forging movements.

In the context of the present application, an electric linear drive is to be understood as meaning, in particular, an electric, in particular electromagnetically operating, linear motor in which the linear rotor for executing a linear translational movement, in particular in the longitudinal direction of the linear rotor, in a stator, in particular fixedly attached to a forging hammer frame is guided or stored. For example, it can be a linear motor with permanent magnet excitation, in particular a solenoid linear motor. As a linear motor, it can be designed, for example, as a synchronous linear motor, for example of a cylindrical design, e.g. with a cylindrical stator and a central, cylindrical through hole in which a cylindrical linear rotor is guided. To this extent, the linear motor can be an electromagnetically operating or operable tubular linear motor.

In the proposed forging hammer, it is provided that the linear runner and the bear are connected to one another with the interposition of a decoupling structure that acts indirectly and / or directly between the linear runner and the bear. In particular, the decoupling structure can be designed and set up for indirect and / or direct decoupling, in particular flexurally elastic decoupling, of the linear rotor and the bear, which is particularly advantageous in the case of an electromagnetic linear motor, in particular a permanent magnet-excited linear motor as included in the invention described herein. For example, a decoupling structure can reduce a mechanical load acting on the rotors and / or stator during operation, for example in the form of longitudinal, transverse, torsional and / or shear vibrations. So in particular a safe running of the linear motor and the associated reliable forging results can be achieved.

The decoupling structure, for example in the form of a two- or three-dimensional connection structure with elasto-mechanical properties, can be designed and set up in such a way that the linear runner is at least partially affected by relative movements of the bear relative to the linear runner that occur during a forging movement, in particular by elasto-mechanical damper mechanisms, can be decoupled.

Relative movements should be understood to mean, in particular, those movements of the bear relative to the linear runner that occur along with the primary up and down movement, or back and forth movement, of the bear and / or during forging, and are caused in particular by the primary movement and / or Forging operations while operating the forging hammer. The primary movement as such can be viewed as a synchronous movement of the linear runner and the bear. Relative movements of the bear that deviate from this can in this respect also be referred to as secondary movements of the bear.

Tilting, deformation, bending, vibrations and / or displacements of the bear and / or tilting, deformation, bending, vibrations and / or occurring with respect to the longitudinal axis or central axis of the linear drive are particularly suitable as relative movements or secondary movements Shifts.

The interposed, in particular flexurally elastic or elasto-mechanical, decoupling structure between the linear runner and the bear can in particular ensure that the linear runner and bear are or can be at least partially, preferably completely, decoupled from one another with regard to the secondary movements that may occur during operation of the bear . In particular, by means of a corresponding decoupling structure an extensive, elasto-mechanical decoupling between the linear motor and the bear can be achieved, which means that less stringent requirements are required for the mechanical strength of the components used in the linear motor.

In particular, it can be avoided, at least largely, that secondary movements of the bear are transmitted to the linear rotor, which would have a disadvantageous effect on the drive and the drive properties of the linear drive. Furthermore, by decoupling the bearing and the linear motor, in particular the linear runner, it can be achieved that mechanical loads actually acting on the linear runner are reduced during operation. In particular, it can be avoided that a magnetization structure formed on or in the linear rotor and made of permanent magnets is fully exposed to the mechanical loads, in particular impacts, occurring during the forging operation.

A, in particular elasto-mechanical, decoupling or a compensation of relative movements can be achieved in particular in that the decoupling structure or at least a section of the decoupling structure is designed to be flexible in bending, in particular elastic in terms of vibration and / or torsion, and deformed accordingly for the purpose of compensation can be, so that a transmission of the respective secondary movement of the bear to the linear rotor can be at least largely avoided or attenuated. According to the invention, the decoupling structure is an elasto-mechanically acting damping structure.

The decoupling structure can comprise specifically designed or configured decoupling segments or decoupling areas for different types of secondary movements, for example tilting relative to the longitudinal axis, displacements transverse to the longitudinal axis, transverse vibrations relative to the longitudinal axis. For example, a decoupling area can include one or more tapers, incisions, beads, openings, recesses, longitudinal and / or transverse grooves, cavities, etc.

As already mentioned, by providing a decoupling structure, in particular a flexurally elastic, decoupling structure, any secondary movements of the bear, such as vibrations, displacements, deformations and / or tilts, are not, or at least essentially not, transmitted to the linear rotor. In this context, it should be mentioned that the present invention is based in particular on the knowledge that in forging hammers with an electric linear drive, which do not have a decoupling structure, in particular the mentioned secondary movements can lead to the running, in particular linear running, of the linear rotor in the associated stator is negatively affected.

For example, a partial transfer of secondary movements of the bear to the linear armature can result in an air gap formed between the linear armature and stator of the electric linear drive being changed or varied over the axial length of the stator during forging operation, which has negative effects on the drive and motor so that forging properties of the forging hammer can result, and possibly damage to the linear rotor and / or stator. By providing a decoupling structure that acts in particular elasto-mechanically in one, two or three dimensions, the aforementioned impairments can advantageously be avoided.

With regard to the term flexurally elastic decoupling structure, it should be noted that the term "flexurally elastic" in the sense of the present application in particular in relation to the flexural elasticity of the material of the bear and / or the linear rotor and / or directly to the decoupling structure of adjacent components and / or in relation to different Sections of the decoupling structure as such should be understood as a relative dimension, to the effect that the decoupling structure or a section thereof can have a deliberately higher, in particular elasto-mechanical, flexural elasticity than the material of the bear and / or the linear rotor and / or that directly adjacent to the decoupling structure Components and / or that at least the section of the decoupling structure can have a deliberately higher flexural elasticity than further sections of the decoupling structure or adjoining areas.

A deliberately higher flexural elasticity than adjacent or adjoining components or sections can be implemented, for example, in that the decoupling structure is tapered at least in sections in the direction transverse, in particular perpendicular, to the direction of movement of the linear rotor, or has a taper, compared to the neighboring or adjoining components. A corresponding taper can, for example, have a concave curvature formed in cross section along the direction of movement of the linear rotor or have a shape shaped in some other way.

A taper formed in connection with the decoupling structure can, for example, be designed in such a way that a diameter of the decoupling structure measured transversely to the direction of movement of the linear rotor, in particular a section of the decoupling structure, by a factor between 0.85 to 0.97, in particular by a factor of about 0.95, is smaller than a correspondingly measured diameter of an adjacent or adjoining component and / or of a further section of the decoupling structure.

For example, there may be a tapered section whose diameter is transverse to the direction of movement of the linear rotor by a factor between 0.85 to 0.97, in particular by a factor of about 0.95 smaller than a maximum diameter of the decoupling structure measured transversely to the direction of movement of the linear rotor.

Furthermore, a targeted higher flexural elasticity than adjacent or adjoining components or sections of the decoupling structure can be achieved by the area content of cross-sections or cross-sectional areas of the decoupling structure being or being varied in a targeted manner at least in sections transversely to the direction of movement.

In particular, the decoupling structure or a section thereof can be designed in its two- or three-dimensional geometric structure in such a way that the surface area of cross-sectional areas varies in the direction parallel to the direction of movement. For example, the two- or three-dimensional structure can have one or more tapers, incisions, beads, depressions, penetrations, recesses, cavities, etc., which are designed so that in a direction parallel to the direction of movement, areas of cross-sectional areas of the decoupling structure between a maximum and a minimum value or vary. A reduction in the surface area compared to adjoining or neighboring components or sections can, for example, be in the range between 0.65 and 0.95, in particular approximately 0.90.

It should be noted at this point that a reduction in the surface area does not necessarily have to be accompanied by a reduction in the overall diameter of the decoupling structure transversely to the direction of movement. In particular in the case of a three-dimensional structure with flexurally elastic, resilient properties in the transverse and / or parallel to the direction of movement, a reduction in the cross-sectional area can be combined with an increase in the overall diameter. In particular, corresponding three-dimensional structures for the decoupling structure can be designed in such a way that a comparatively low material fatigue is achieved, and a comparatively long service life for the decoupling structure can thus be achieved during operation with continued flexurally elastic loading of the decoupling structure.

In refinements, the decoupling structure can comprise at least one, in particular elasto-mechanically designed, flexurally elastic, decoupling element which can be designed and set up in such a way that the linear armature with respect to secondary movements of the bear occurring longitudinally and / or transversely to the longitudinal axis of the linear armature during a forging movement, eg vibrations, displacements, deformations and / or tilts, at least largely, is decoupled.

The flexurally elastic decoupling element can in particular be designed in such a way that the mentioned variation in the diameter and / or in the surface area of the cross-sectional areas is achieved or implemented over the course of the decoupling element parallel to the direction of movement of the linear rotor.

According to the invention, the decoupling structure can be designed in one piece with the linear rotor, it being possible, for example, to be designed at the end of a piston rod or piston-like rod or structure. It is also possible for the decoupling structure to be designed as a separate construction element and to be connected to the linear rotor and / or a piston thereof with a form fit, material fit and / or force fit.

With one or more corresponding decoupling elements, it can be achieved, for example, that secondary movements that may occur along and / or transversely to the direction of longitudinal movement of the linear rotor can be counteracted, so that, for example, by at least partial vibration decoupling of the linear rotor and bear, an advantageous geometry of the Air gap between the linear rotor and stator can be reached or maintained. Furthermore, one or more decoupling elements make it possible to at least reduce the mechanical load, in particular vibration load, of the linear rotor during operation of the forging hammer, for example to at least partially eliminate it, in particular in such a way that damage to the linear rotor and possibly permanent magnets attached to it or in it can be avoided.

In refinements, it can be provided that the forging hammer further comprises a first linear guide or linear bearing formed between the stator of the linear drive and the bear, in particular in alignment with the central axis of the linear drive, in which the linear rotor is guided and supported in the longitudinal direction.

The first linear guide can be, for example, a bearing, such as a roller or sliding bearing, in particular a sliding or guide bush, through which the linear rotor is supported so that it can be moved in the axial direction and transversely to the axial direction, in particular with or largely free of play, can be supported.

By providing such a first linear guide, in cooperation with the decoupling structure, in particular a stabilization of the axial run of the linear rotor, in particular the axial position of the linear rotor in the stator, can be achieved. For example, in support of the decoupling structure, deflections occurring transversely to the axial direction, which can occur during operation of the forging hammer, for example due to secondary movements of the bear on the linear rotor, can at least be counteracted. By stabilizing the position and running of the linear rotor, it can also be achieved that the geometry, shape and / or width of the air gap formed between the linear rotor and stator is stabilized during the forging operation, and variations in the air gap geometry caused by forging processes are at least suppressed or at least largely avoided be able. This leads in particular to improved drive properties of the linear drive and thus, at least indirectly, to improved forging results.

According to a further embodiment, it can be provided that the forging hammer further comprises a second linear guide on a side of the linear drive facing away from the bear, in which or through which the linear rotor is guided in the longitudinal direction, and in particular is supported transversely to the longitudinal direction.

The second linear guide can be designed, for example, as a guide bushing, bearing or the like, and can in particular be connected to or attached to a housing or a support structure and / or the stator. The second linear guide can be designed, for example, as a type of bushing or sleeve, in particular closed on one side, in which a corresponding Part or section of the linear rotor can be performed during the operation of the forging hammer. In embodiments it can be provided that a length of the bushing or sleeve measured in the axial direction, ie parallel to the direction of movement of the linear rotor, is at least as large as 1 times the diameter of the linear rotor.

By means of the second linear guide it can be achieved that on the one hand the linear armature is movably supported in the axial direction, and on the other hand that the linear armature is supported or held transversely to the axial direction, in particular with or without play.

A particularly stable run of the linear rotor can be achieved if the electric linear drive has both the first and the second linear guide. In other words, it is particularly advantageous if the linear rotor is mounted axially on both sides of the stator, on the one hand in the first linear guide facing the bear and on the other hand in the second linear guide facing away from the bear.

In particular, the linear armature, the first and second linear guides can be designed and designed relative to one another in such a way that the linear armature is always guided and supported in both the first and second linear guides over an entire linear movement cycle. The linear rotor, the first and second linear guides can be designed in such a way that the first axial end region of the linear rotor facing the bear in the assembled state is always guided in the first linear guide, and a second axial end region facing away from the bear in the assembled state is always guided in the second linear guide.

In particular, through the interaction of the first and second linear guides, the linear armature and stator can be aligned with one another at least over the respective overlap area of the linear armature and stator, in the case of a cylindrical linear motor, concentrically, ie axially aligned are arranged to each other. It can thus be achieved that variations in the air gap are largely avoided.

By using the first and second linear guide, a linear drive can be implemented with a linear motor, in which the linear rotor is guided in a central rotor space, e.g. in the form of a through-hole or through-opening, of a stator with a hollow-cylindrical geometry, the first and second linear guides facing away from each other axial end faces or ends of the stator are arranged so that guide elements, for example guide bushes, the first and second linear guide are axially aligned with the rotor space.

In particular in the case of configurations with a cylindrical geometry of the stator and linear rotor, the width of the air gap measured between the linear rotor and stator can be, for example, 2 mm.

In refinements, the first and / or second linear guide can be present or formed in or on a support or carrying structure for a linear motor of the electric linear drive. In particular, the first and / or second linear guide can be present or formed on or in a housing structure for an electric linear motor of the electric linear drive. Support or support structure can, for example, be components of the housing structure.

The housing structure can, for example as a load-bearing element, for example have a housing base on which the stator of the linear motor can be held, in particular fixed and supported. The first linear guide can be formed in or on the housing bottom, the first linear guide being at least partially attached and fixed in a through opening of the housing bottom, wherein the through opening, in particular through hole, can be formed such that it is axially aligned with the rotor space , and the linear rotor can be moved therein in accordance with the respective linear movement during operation. the The first linear guide, for example a plain bearing structure, can for example be arranged to run circumferentially along the through opening, so that the plain bearing structure forms a through opening for the linear rotor that is concentric to the through opening.

The second linear guide can be formed on an end face facing away from the first linear guide, in particular on an end face facing away from the housing base, of the housing or of the stator. The second linear guide can comprise a guide cylinder, in particular provided with a support structure, for example externally designed. The guide cylinder can be attached to a support or guide plate, with support ribs connecting the guide plate and the guide cylinder being provided for mechanical stabilization.

Support walls can extend from the housing base on laterally opposite sides of the stator and parallel to the longitudinal direction of the linear motor, to which the guide cylinder, in particular the guide plate, can be attached. Support walls and housing base can be stiffened against each other by one or more support ribs, in particular in such a way that deformation of the housing, in particular due to torsional, shear and / or longitudinal vibrations, can at least largely be avoided during operation of the forging hammer.

In embodiments, the housing can comprise a housing jacket which is fastened to the housing base and / or to the side support walls and which is designed to surround at least the stator of the linear motor in the assembled state. The housing jacket can comprise one or more mutually connected housing jacket elements which each protectively surround a section of the stator of the linear motor. The housing jacket elements are preferably detachably connected to one another, for example via flanges which are arranged corresponding to one another and formed on adjacent housing jacket elements. The housing jacket elements can be connected to one another and to the housing base and / or the supporting walls trained cylinders, cylinder shells or partial cylinder shells, for example cylinder half-shells, include. A correspondingly modular construction of the housing offers advantages in particular with regard to maintenance work to be carried out.

In refinements, it can be provided that the housing, in particular the housing base, comprises one or more stop buffers on a side facing the bear, which are designed in such a way that in the event of a particularly unusual collision between the bear and the housing, the mechanical Load on the linear motor can at least be weakened or buffered.

The housing as such can be mounted on an underframe of the forging hammer in configurations with the linear motor fastened in and on the housing. Between the underframe and the housing, the underframe can have a bear guide designed and set up for linear guidance of the bear, which bear guide is formed on or in the underframe and / or is mechanically connected to it. The bear guide is advantageously connected to the underframe in this way, and the linear motor and the housing are preferably connected to the underframe in such a way that the linear motor at least largely with regard to the mechanical connection between the linear drive and the bear and bear guide via the underframe is mechanically decoupled. For this purpose, absorber or damping elements or structures connected between the subframe and the linear drive can be provided, for example.

In particular, with the structure proposed here, it is possible to decouple existing, direct and / or indirect mechanical connections between the linear drive and the bear from the transmission of shocks and / or vibrations. In this way it can be achieved in particular that the linear motor is exposed to comparatively low mechanical loads during the forging operation, whereby on the one hand the material stress on components of the linear motor is reduced by mechanical decoupling and, on the other hand, reliable operation of the linear motor can be ensured in that variations in the air gap formed between the stator and linear rotor due to the mechanical decoupling can at least largely be avoided during operation.

According to one embodiment, the linear rotor, at least in the connection area to the decoupling structure, and / or the decoupling structure as such can have a piston-like, in particular cylinder, structure.

The decoupling structure can be designed in such a way that the flexural strength is reduced in relation to components or elements of the forging hammer that are directly adjacent or connected to it, in particular by a factor less than the flexural strength of the adjacent components and / or elements.

In particular, in configurations with a cylinder-like or piston-like linear runner, for example in the form of a piston rod, it can be provided that an axial length of the first and / or second linear guide, in particular of guide surfaces of the first and / or second linear guide, measured in the direction of movement of the linear runner, at least so is as large as 1 times the diameter of the linear rotor, in particular in the area interacting with the first or second linear guide. In short, in corresponding configurations, the axial length of the first and / or second linear guide can be at least 1 times the diameter of the corresponding section of the linear rotor.

In refinements, it can be provided that a ratio of the diameter of the cylinder structure to the length of the decoupling structure formed between the linear rotor and the bear is in the range between 1/5 to 1/2. By appropriate or suitable setting of the length and / or diameter of the cylinder structure formed between the linear rotor and the bear, in particular the flexural rigidity or, alternatively, the flexural elasticity can be changed and set in a targeted manner.

In refinements, it can be provided that the decoupling structure is formed between the linear runner or an extension adjoining the linear runner and a fastening structure designed to fasten the bear to the linear runner.

The fastening structure can be designed, for example, as a wedge or conical segment that can be connected to the bear in a form-fitting or frictional connection, in particular that engages the bear in the axial direction. In particular with corresponding wedge or conical segment connections, a comparatively robust and reliable connection between the bearer and the linear rotor can be achieved by providing the decoupling structure.

In refinements, in particular according to claim 12, a forging hammer can be provided which can be constructed, for example, in accordance with the refinements described above, and which comprises an or the electric linear drive with a or the linear rotor. The linear rotor can comprise a magnet section formed from a plurality of permanent magnets arranged one behind the other in the axial direction and extending in the axial direction.

In its extension at an axial end of the linear rotor, for example, a cylindrical extension can be attached to the magnet section, on or in which, for example, the or a decoupling structure as described herein and / or the or a fastening structure designed for fastening to the bear as described herein can be formed.

The permanent magnets of the magnet section can be configured, for example, as magnet ring disks and axially aligned one behind the other. In this arrangement, a cylindrical magnet section can be achieved, which can be performed, for example, in a cylindrical rotor space of a stator with a hollow cylindrical geometry.

In configurations with a magnet section composed at least partially of magnetic ring disks, the linear rotor can have a central piston rod which passes through central through holes in the magnetic ring disks. In other words, the ring magnetic disks can be slipped or threaded onto a piston rod, so that the piston rod reaches through the through holes and the ring magnetic disks are arranged axially in alignment with one another. The piston rod and magnetic ring disks can, so to speak, be viewed as a cylindrical magnetization structure for the linear rotor.

With the aid of the piston rod, the ring magnet disks can be or be fixed on the linear rotor aligned in and transversely to the longitudinal direction. Correspondingly, fastening elements, for example clamping nuts, which are present or attached on both sides, for example at the end, of the magnet section can be provided in configurations. The fastening elements and the piston rod can, for example, be designed in such a way that the permanent magnets and piston rod can be braced together by the fastening elements, for example for the purpose of improving the mechanical stability.

In further refinements, the permanent magnets can be provided and arranged in the magnet section in such a way, or have a configuration, according to which the permanent magnets are alternately magnetized radially and axially in the axial direction. Such a magnetization structure with alternating radial magnetization and axial magnetization has proven to be particularly advantageous with regard to use in a forging hammer, in particular using a stator with a hollow-cylindrical geometry.

In configurations, laminated sheets, in particular peelable laminated sheets, can be arranged between axially successive permanent magnets. Such laminated sheets, for example in the form of stainless steel laminated sheets, can be interposed, for example, to compensate for manufacturing tolerances of the permanent magnets and / or to set a respective magnetization structure.

A linear rotor suitable for forging hammers can be implemented in particular through the proposed construction of the magnet section, for example comprising permanent magnets braced together on a piston rod by interposed laminations.

According to embodiments, a neodymium-iron-boron (NdFeB) material is preferably used as the material for the permanent magnets. Such materials in particular have proven to be advantageous for the accelerations and force effects required in forging hammers. However, the permanent magnets can also be made of other materials and, in particular, the permanent magnets can be designed as sintered bodies.

In further refinements, the linear rotor can comprise at least one guide sleeve in an area that is adjacent, preferably directly adjoining, the magnet section. Preferably, an outer surface of the guide sleeve forms a bearing surface with the aid of which the linear rotor can be mounted so as to be movable in the longitudinal direction in the first or second linear guide. The guide sleeve can be designed in such a way that, in order to support or mount the linear rotor, its outer surface rests against an inner surface of the linear guide or can be mounted in a sliding manner.

In order to improve the tribological properties of the guide sleeve, it can have one or more sliding guide rings according to further configurations. The outer diameter of the sliding guide rings is preferably selected so that they are in a linear guide designed as a guide bush, for example, the second linear guide, can be slidably received.

In refinements, the guide sleeve can be designed in such a way that only the guide sleeve is in contact with a corresponding guide surface, so that the guide sleeve can in this respect be viewed as part of a linear bearing for the linear actuator.

According to embodiments, a stop sleeve can be provided at an end of the magnet section opposite the guide sleeve, which can in particular be designed to interact with a stop present on the first linear guide, for example to limit the possible freedom of movement of the linear rotor in the longitudinal direction.

In particular, the linear rotor can be designed in such a way that it is or can be supported in two regions spaced apart from one another in the longitudinal direction, preferably immediately adjacent to the longitudinal ends of the magnet section.

In refinements, it can be provided that an outer surface of at least the magnet section is provided with a coating in order to protect at least the permanent magnets from external influences such as dirt, dust, moisture, etc. A resin, in particular epoxy resin, or a material comprising a resin can be used as the material for the coating.

As already mentioned elsewhere, the linear drive can be designed as a cylindrical, ie tubular, linear motor. In the case of such configurations in particular, the linear rotor, but at least the magnet section or the magnetized part of the linear rotor, can have a cylindrical shape with a preferably approximately circular cross section. Correspondingly, the stator can be designed with a cylindrical central passage.

In embodiments, the linear motor can be designed as a permanent magnet excited synchronous linear motor. With the appropriate forging hammers, forging processes can be controlled comparatively precisely and precisely.

A travel or stroke path of the linear rotor can, for example, be between 700 mm and 800 mm, in particular around 750 mm. However, the invention proposed here is also suitable for other stroke paths, in particular larger or else smaller stroke paths of the linear rotor.

In refinements, a linear motor of the linear drive can have a modular structure parallel to the direction of movement of the linear rotor. For example, the linear rotor can have a predetermined, but variable number of permanent magnets arranged one behind the other. The stator can, for example, have a predetermined, but variable number of magnet coils connected in series parallel to the direction of movement, for example each comprising a coil carrier and a corresponding coil winding. The housing can, for example, have one of the plurality of housing segments connected one behind the other. With the modular structure, it is possible to flexibly adapt the linear motor according to the respective requirements and boundary conditions.

In refinements, the linear motor can have a housing with a one-part or multi-part housing jacket, in particular with a modular structure, which is supported on a housing base or a base plate. For mechanical reinforcement, reinforcement elements, in particular reinforcement ribs, can be provided between the base plate and the housing shell.

In embodiments, the base plate can have a fastening interface by means of which the linear motor can be attached to a support frame of the linear hammer. The base plate can in particular be designed in such a way that different fastening interfaces can be implemented, for example on its underside, so that it is possible to mount a respective linear motor on different linear hammers.

In refinements, the housing, in particular the base plate or the housing base, can be connected to one or the support frame of the linear hammer in a force-locking manner. For example, screw connections provided at respective corners of the base plate can be used for fastening.

A corresponding screw connection can, in configurations for example, comprise a damping element and / or damping bearing element, for example a metal rubber bearing, between screw elements, for example screw head and / or screw nut.

In refinements, the base plate or the housing base can be mounted and fastened to the hammer frame by means of interposed damping or damping strips.

In particular, damping elements and / or damping strips and other damping or absorber components that are present between the linear motor and hammer frame contribute to the decoupling of the linear motor from the hammer frame, so that mechanical shocks, vibrations and the like that occur during forging processes can at least be attenuated, so that a direct loading of the linear motor with occurring mechanical forces can at least be reduced.

FIG. 1

eine perspektivische Ansicht eines Schmiedehammers;

FIG. 2

eine Schnittdarstellung des Schmiedehammers;

FIG. 3

ein Detail des Schmiedehammers nach FIG. 2;

FIG. 4

ein weiteres Detail des Schmiedehammers nach FIG. 2,

FIG. 5

eine beispielhafte Ausgestaltung eines Abschnitts eines Linearläufers;

FIG. 6

eine perspektivische Ansicht einer weiteren Ausführungsform eines Schmiedehammers; und

FIG. 7

eine Schnittdarstellung des Schmiedehammers der weiteren Ausführungsform.

Embodiments of the invention are described in more detail below with reference to the attached figures. Show it:

FIG. 1

a perspective view of a forging hammer;

FIG. 2

a sectional view of the forging hammer;

FIG. 3

a detail of the blacksmith's hammer FIG. 2 ;

FIG. 4th

after another detail of the blacksmith's hammer FIG. 2 ,

FIG. 5

an exemplary configuration of a section of a linear rotor;

FIG. 6th

a perspective view of another embodiment of a forging hammer; and

FIG. 7th

a sectional view of the forging hammer of the further embodiment.

FIG. 1 shows a perspective view of a forging hammer 1, with a hammer frame 2 with two lateral uprights 3 for supporting a crosshead 4.

A like in FIG. 1 The forging hammer 1 shown can comprise a lower insert 5, which can be fastened in the hammer frame 2 by means of an insert wedge 6, and have a receptacle 7 for a lower hammer die 8, which in the forging hammer 1 shows a sectional view FIG. 2 you can see.

The forging hammer 1 further comprises a tubular solenoid linear motor 9 fastened and supported on the upper crosshead 4, in particular a solenoid-permanently excited synchronous linear motor.

The solenoid linear motor 9, designed as an electric linear drive, comprises a stator 10 and a linear rotor 11 guided therein in the longitudinal direction (see FIG FIG. 2 ).

The linear rotor 11 is coupled to a bear 12, which in turn is guided in two bear guides 13 formed on the stands 3, so that the bear 12 can be moved up and down by the electric linear motor 9.

The linear solenoid motor 9 is housed in a housing 32. The housing 32 has a modular structure and, in the example shown in the figures, comprises a housing base 33 with a cylindrical first housing jacket 34 attached and fixed to it Support ribs 35, or support brackets, mechanically stiffened with respect to the housing base 33.

The housing 32 further comprises a cylindrical second housing jacket 36, which is connected to the first housing jacket 34 via a releasable flange connection 37, in the present example in a force-locking manner.

On the side of the second housing shell facing away from the first housing shell 34, a linear bearing 38, described in more detail below, is attached, which comprises a base plate 39 and a cylindrical guide bushing 15 attached to the base plate 39, in particular in a materially bonded manner. The guide bush 15 and base plate 39 are mechanically stiffened against one another by means of second support ribs 40 or support brackets attached to them.

By a mechanically comparatively stable construction of the housing 32, on the one hand, protection of electronic components of the solenoid linear motor 9 from mechanical influences can be achieved. On the other hand, the modular structure makes it possible to achieve that components accommodated in the housing are comparatively easily accessible, for example when maintenance work may be required.

The solenoid linear motor 9 is connected to the underframe of the forging hammer 1, that is to say the uprights 3, by means of the housing bottom 33 of the housing 32. Specifically, the housing bottom 33 is screwed to the stand heads 3 of the stand 3, which are designed in a T-shape. Positioning elements and / or dampers or absorber elements can be present between the housing base 33 and the stator heads. The damper or absorber elements can be designed a To at least dampen the transmission of mechanical shocks and / or vibrations from the underframe to the housing 32.

As in FIG. 2 As shown, the bear 12 carries an upper hammer die 14 which is fixed thereto and corresponds to the lower hammer die 8.

In operation of the forging hammer 1, the bear 12 is moved up and down by the corresponding drive of the linear rotor 11 by the solenoid linear motor 9, wherein in the lower base points of the bear 12 respective forging operations can be carried out on a workpiece (not shown).

Like in particular from FIG. 2 As can be seen, the linear rotor 11 is designed like a piston rod and has a length measured parallel to the longitudinal axis L which is greater than the length of the stator 10 measured parallel to the longitudinal axis.

At an upper end, ie at an end facing away from the bear 12, the solenoid linear motor 9 has, as already described, the guide bush 15, which in the detailed illustration of FIG FIG. 3 is shown in more detail.

The guide bushing 15 is aligned and arranged as an extension of the running axis or guide axis L of the solenoid linear motor 9 and is designed such that the linear rotor 11 is guided in the longitudinal direction and is supported transversely to the longitudinal direction.

At a lower end of the solenoid linear motor 9 facing away from the upper end, there is a support bearing 16 which, in the illustration in FIG FIG. 3 , which shows an enlarged section of the FIG. 2 shows can be seen in more detail.

The support bearing 16 is arranged in alignment with the longitudinal axis L and in alignment with the upper guide bushing 15, and is designed and set up in such a way that the linear rotor 11 is guided therein in the longitudinal direction and is supported transversely to the longitudinal direction.

At the end facing the bear 12, the linear rotor 11 has a piston rod extension 17 which is in the retracted position of the linear rotor 11, as in FIG FIG. 2 and FIG. 4th shown, extends between the support bearing 16 and the bear 12.

The piston rod extension 17 comprises a piston section 18, a fastening structure 19 provided at the distal end and a decoupling structure 20 located between the piston section 18 and the fastening structure.

The fastening structure 19 is designed in the form of a wedge or conically tapered section, and positively, in particular frictionally, connected to the bear 12 by means of a retaining bushing 21 in a corresponding recess or a through or blind hole of the bear 12.

The decoupling structure 20 comprises a flexurally elastic decoupling section 22 arranged between the piston extension and the fastening structure 19. The decoupling section 22 has an increased flexural elasticity compared to the neighboring components and materials.

The increased flexural elasticity or reduced flexural rigidity compared to the neighboring or directly adjoining components or materials can be brought about, for example, by one or more tapers formed in the area of the decoupling structure, for example with a structure concave with respect to the longitudinal axis L, by using or providing a correspondingly flexurally elastic Material, through cuts, recesses, openings, etc.

In particular, a ratio between the diameter of the linear rotor 11 or a piston of the linear rotor to the diameter of the decoupling structure can be used 20, each measured transversely to the direction of movement of the linear rotor 11, lie in the range of approximately 0.95. In particular, ratios in the range from 0.80 to 0.97, or 0.85 to 0.95, with which comparatively advantageous elasticity properties can be achieved for forging processes, are also possible.

When the forging hammer 1 is in operation, the guide bushing 15, the support bearing 16 and the decoupling structure act in forging processes in which the bear 12 is moved up and down to machine a workpiece, and in which the workpiece is or can be deformed at a lower reversal point 20 together in such a way that the linear rotor 11 and bear 12 are decoupled with respect to the relative movements of the bear 12 with respect to the linear rotor 11, and the linear rotor 11 is properly guided in the stator 10. In other words, through the interaction of the guide bushing 15, the support bearing 16 and the decoupling structure 20, in particular the decoupling section 22, and any dampers and / or absorber elements present between the hammer frame 2 and the housing 32, secondary movements of the bear 12 can be compensated for or absorbed, and so on a transfer to the linear rotor 11, at least largely, to avoid.

More precisely, the decoupling structure 20, in particular the decoupling section 22 and / or decoupling section 22 and piston section 18, does not prevent secondary movements of the bear 12 occurring during a forging process, for example in the form of tilting with respect to the longitudinal axis, displacements or vibrations transverse to the longitudinal axis or the like , or not fully transferred to the linear rotor 11.

Support bearing 16 and guide bush 15 have a stabilizing effect with regard to the position and the running of the linear rotor 11 in the stator 10, and an air gap formed between the linear rotor 11 and stator 10 in the interior of the linear motor 9, and in particular contribute to the transmission of secondary movements of the Bear 12 on the linear runner 11 can be avoided.

The proposed measures, i.e. in particular the provision of the decoupling structure 20, the lower support bearing 16 and the upper guide bush 15, can ensure that the linear rotor 11 is optimally guided in the stator 10. In particular, the stabilization of the linear rotor 11 and its mechanical decoupling from the bear 12 prevent the geometry of the air gap formed between the linear rotor 11 and stator 10 in the interior of the solenoid linear motor 9 from being influenced, in particular varied, by forging movements. Changes in the air gap during the operation of the linear motor have an adverse effect on the operation of the solenoid linear motor 9, which in turn can lead to impairments in the forging result and / or to reduced energy efficiency. In other words, the decoupling structure 20 and the combined effect and interaction with the linear guides designed as guide bushing 15 and support bearing 16 can stabilize the position of linear rotor 11 during the forging operation and at least largely independent of secondary movements of the bear 12 is.

FIG. 5 shows an embodiment of a section of the linear rotor 11. The linear rotor 11 according to FIG FIG. 5 comprises an approximately centrally located magnet section 23 extending in the axial direction.

The magnet section 23 comprises a plurality of first permanent magnets 24 and second permanent magnets 25. The first permanent magnets 24 are axially magnetized permanent magnets, while the second permanent magnets 25 are radially magnetized permanent magnets. The first permanent magnets 24, measured in the direction parallel to the longitudinal axis L, are narrower than the second permanent magnets 25.

In each case between two adjacent permanent magnets (not shown) laminated sheets are arranged, which are designed in particular to meet manufacturing tolerances of the permanent magnets with respect to the surfaces oriented in the longitudinal direction L.

The permanent magnets 24, 25 are designed as ring disks with a central through hole. The linear rotor 11 has a piston rod 26 which passes through the through holes of the permanent magnets 24, 25 and forms a central seat for the permanent magnets 24, 25.

Immediately adjacent to the magnet section 23, the linear rotor 11 has a guide sleeve 27 with several sliding guide rings. The guide sleeve 27, in particular the sliding guide rings, form / s part of a plain bearing with which the linear rotor 11 in the guide bush 15 (see FIG FIG. 3 ) can be or is longitudinally displaceable. An inner surface of the guide bush 15 can accordingly be designed as a counter bearing surface for the sliding guide rings.

The permanent magnets 24, 26, laminated sheets and the guide sleeve 27 are fastened by means of clamping nuts 28 which are fastened or fixed on both sides of the piston rod 26 and which each abut against a stop nut 29. The clamping nuts 28 and stop nuts 29 as well as corresponding fastening points, in particular threads, the piston rod 26 and the piston rod 26 as such are designed such that the permanent magnets 24, 25 and piston rod 26 are braced together when the stop nuts 29 and clamping nuts 28 are properly attached. In this way, in particular, improved mechanical stability, in particular of the magnet section 23, can be achieved.

At the end of the linear rotor 11 facing away from the guide sleeve 27, in the assembled state, as in the embodiment according to FIG FIG. 4th is shown, the piston portion 18, the fastening structure 19 and the decoupling structure 20 may be attached.

The magnet section 23 can have a protective coating, which can consist, for example, of an epoxy resin or comprise an epoxy resin. The permanent magnets 23, 24 of the magnet section 23 in particular can be protected from external influences by a corresponding coating.

Corresponding to the magnet sections 24, 25, the stator 10 of the tubular solenoid linear motor 9, which is designed in a hollow cylindrical geometry, can be arranged along the longitudinal direction L and spaced apart from each other ring coils 30 (see FIG. 2 exhibit). By means of a corresponding control (not shown), the ring coils 30 can be controlled in such a way that the magnet section 23 is moved up and down in the stator, with corresponding forging movements of the bear 12 being carried out.

The stator 10 with toroidal coils 30 can, as for example in the embodiment according to FIG. 2 is shown, received in the modular housing 32, in particular fastened therein. As a result of the approximately centrally located flange connection 37 of the housing halves, it can be achieved that the components located within the housing 32 are comparatively easily accessible, for example for maintenance purposes and the like.

An interface of the stator 10 or the housing 32 with which the solenoid linear motor 9 is attached to the hammer frame 2 can be designed such that the linear drive designed as described herein can also be installed, i.e. retrofitted, on already existing forging hammers.

In order to avoid or at least largely prevent any damage to the linear drive, in particular to the permanent magnets 24, 25, stop buffers 31 (see FIG FIG. 2 ) be provided.

To compensate for pressure fluctuations that can occur inside the housing during operation of the forging hammer due to the movement of the linear rotor 11, the housing 32, in particular the housing wall, and / or the linear bearing 38 can have corresponding air inlet and air outlet elements.

Overall, the housing 32 can be designed such that the stator 10 and linear rotor 11 are essentially encapsulated, in particular mechanically encapsulated, and largely protected from external influences. In particular in the case of partial or even complete encapsulation, it may be necessary to provide the previously mentioned pressure compensation elements.

FIG. 6th shows a perspective view of a further embodiment of a further forging hammer 1a. The further forging hammer 1.1 is constructed similarly to the forging hammer 1 according to FIG. 1 , wherein, unless otherwise described, elements and components labeled with the same reference symbols have functions and / or properties that correspond to one another and / or correspond to one another.

In contrast to the forging hammer 1 after FIG. 1 the further forging hammer 1a comprises a linear motor which is shorter measured in the longitudinal direction L and which is also designed as a solenoid linear motor, and to which reference is made below under the designation of further linear motor 9.1.

The further linear motor 9.1, which is shown in FIG. 7th is shown in section, comprises a stator 10, which compared to the embodiment according to FIG. 1 and FIG. 2 is shortened. The stator of the further linear motor 9.1, measured in the longitudinal direction, can be designed, for example, to be half as long as that of the linear motor FIG. 1 and FIG. 2 . In the case of the further linear motor 9.1, the linear rotor 11 can also be designed correspondingly shortened, the magnet section and the adjoining sections of the linear rotor 11 corresponding to the method shown in FIG FIG. 5 shown example can be configured.

Due to the shortened shape of the further linear motor 9.1, which is designed as a tubular linear motor, the housing 32 comprises only one housing jacket 34. The one housing jacket 34 is similar to the embodiment according to FIG FIG. 1 and FIG.2 mounted on a housing base 33, in particular welded. For stiffening purposes, the housing jacket 34 and the housing base 33 are supported against one another via first support ribs 35, it being possible for the first support ribs 35 and the housing base 33, for example, to be welded to one another.

On the side of the housing jacket 34 facing away from the housing base 33, there is one as in the embodiment of FIG FIG. 1 and FIG. 2 trained linear bearing 38 attached, in particular screwed. The linear bearing 38 is according to the configuration FIG. 1 to FIG. 4th formed, and reference is made to corresponding statements.

Similar to the design after FIG. 1 to FIG. 4th the further linear motor 9.1 received in the housing 32 is connected to the hammer frame 2 via the housing base 33.

As if from the perspective of the FIG. 6th and FIG. 7th As can be seen, the housing base 33 is connected to the hammer frame 2 in a force-locking manner, with screw connections 41 provided at the respective corners of the housing base 33 being used in the present example. A corresponding screw connection 41 can, for example, comprise a metal rubber bearing 43 between screw head 42.1 and screw nut 42.2. Furthermore, the housing bottom 33 can be mounted and fastened to the support heads 45 of the hammer frame 2 by means of interposed damping or absorber strips 44. This structure and this method of fastening essentially corresponds to that of the forging hammer 1 FIG. 1 to FIG. 4th .

The metal rubber bearings 43 and / or damping or damping strips 44 contribute in particular to the decoupling of the linear motor 9, 9.1 from the hammer frame, so that mechanical impacts, vibrations and the like that occur during forging processes can at least be attenuated, so that a direct loading of the linear motor 9, 9.1 with occurring mechanical forces can at least be reduced.

For the in FIG. 6th and FIG. 7th The further linear motor 9.1 shown results in yet another advantage, because the modular design of the housing 32, the linear rotor 11, including, for example, several ring-shaped permanent magnets connected in series, and also the stator 10, which can include several winding bodies 46 connected in series with corresponding coil windings, can in particular the overall length of the linear motor varies at least within certain limits and, in this respect, can be adapted comparatively flexibly to the respective requirements.

Not least due to the fact that the interface for attaching the bear, as well as the interface for attachment to the hammer frame, can be designed according to the conventional, hydraulically operated forging hammers, it is possible to use conventional, hydraulically operated forging hammers according to the solutions proposed here with electric Equip or retrofit linear motors without significant structural changes, for example to the hammer frame 2, being necessary.

Overall, it can be seen that the solution proposed here, in particular the use of an electric linear drive, for example a linear motor in combination with a decoupling structure, and in particular first and second linear guides, can provide a new type of forging hammer. In particular, with the construction proposed here, a forging hammer with a permanent magnet-excited linear motor provided for driving the bear can be implemented, with which sufficient impact forces and accelerations for the bear can be achieved, while at the same time a comparatively precise position control of the bear is possible.

List of reference symbols

1

Blacksmith hammer

1.1

another blacksmith hammer

2

Hammer frame

3

Stand

4th

Crosshead

5

mission

6th

Insert wedge

7th

admission

8th

lower hammer die

9

Solenoid linear motor

9.1

another linear motor

10

stator

11th

Linear runner

12th

bear

13th

Bear leadership

14th

upper hammer die

15th

Guide bush

16

Support bearing

17th

Piston rod extension

18th

Piston section

19th

Fastening structure

20th

Decoupling structure

21

Retaining sleeve

22nd

Decoupling section

23

Magnet section

24

first permanent magnet

25th

second permanent magnet

26th

Piston rod

27

Guide sleeve

28

Clamping nut

29

Stop nut

30th

Toroidal coil

31

Stop buffer

32

casing

33

Case back

34

first housing jacket

35

first support rib

36

second housing jacket

37

Flange connection

38

Linear bearing

39

Base plate

40

second support rib

41

Screw connection

42.1

Screw head

42.2

Screw nut

43

Metal rubber bearings

44

Damping or damping strips

45

Carrying head

46

Winding body

L.

Longitudinal axis

Claims (15)

1. A forging hammer (1) comprising an electric linear drive (9) with a linear runner (11) and a bear (12) coupled to the latter for the purpose of executing forging movements, characterized in that linear runner (11) and bear (12) are connected to one another with the interposition of a decoupling structure (20) acting between linear runner (11) and bear (12), in that the decoupling structure (20) is constructed in one piece with the linear runner (11), or is connected as a separate construction element in a form-fitting, material-fitting and/or force-fitting manner to the linear runner (11) and/or a piston (17) of the linear runner (11), and in that the decoupling structure (20) is designed and set up as an elasto-mechanically acting damping structure for at least partially decoupling the linear runner (11) from relative movements of the bear (12) relative to the linear runner (11) occurring during a forging movement.
2. Forging hammer (1) according to claim 1, wherein the decoupling structure (20) comprises at least one (20) flexible elastic decoupling element (22) which is constructed and arranged to decouple the linear runner (11) with respect to vibrations, displacements, deformations and/or tilting of the bear (12) occurring longitudinally and/or transversely to the longitudinal axis (L) of the linear runner (11) during a forging movement.
3. Forging hammer (1) according to any one of claims 1 or 2, wherein the decoupling structure (20) for different types of secondary movements, in particular tilting relative to the longitudinal axis (L), displacements transverse to the longitudinal axis (L), transverse vibrations with respect to the longitudinal axis (L), each comprising specifically formed or arranged decoupling segments (22) or decoupling regions (22), wherein the decoupling region (22) optionally comprises one or more tapers (22), incisions, beads, apertures, recesses, longitudinal and/or transverse grooves, and/or cavities.
4. Forging hammer (1) according to any one of claims 1 to 3, wherein the decoupling structure (20) has a taper (22) at least in sections in a direction transverse, in particular perpendicular, to the direction of movement (L) of the linear runner (11), wherein the taper (22) optionally has a concave curvature formed in cross-section along the direction of movement of the (L) linear runner (11), and/or
   the surface area of cross-sections or cross-sectional areas of the decoupling structure (20) transverse to the direction of movement (L) is varied in a systematic manner, at least in sections.
5. Forging hammer (1) according to any one of claims 1 to 4, wherein the decoupling structure (20) is formed at the end of the piston rod (17).
6. Forging hammer (1) according to any one of claims 1 to 5, further comprising a first linear guide (16), in particular a linear bearing, formed between the stator (10) of the linear drive (9) and the bear (12), in which linear guide the linear runner (11) is guided in the longitudinal direction (L).
7. Forging hammer (1) according to claim 6, wherein the first linear guide (16) is provided or formed in or on a supporting structure for a linear motor (9) of the electric linear drive (9), and wherein optionally a length of the first linear guide (16) measured parallel to the direction of movement (L) of the linear runner (11) is at least as great as 1 times the diameter of the linear runner (11).
8. Forging hammer (1) according to any one of claims 1 to 7, further comprising, on a side of the linear drive (11) facing away from the bear (12), a second linear guide (15) in which the linear runner (11) is guided in the longitudinal direction (L), in particular is supported transversely to the longitudinal direction (L).
9. Forging hammer (1) according to claim 8, wherein a length of the second linear guide (15) measured parallel to the direction of movement (L) of the linear runner (11) is at least as great as 1 times the diameter of the linear runner (11).
10. Forging hammer (1) according to claims 6 and 8, wherein the linear runner (11), the first (16) and second linear guide (15) are formed and designed relative to each other in such a way that over an entire linear movement cycle the linear runner (11) is always guided and supported in both the first (16) and second linear guide (15).
11. Forging hammer (1) according to any one of claims 1 to 10, wherein the decoupling structure (20) is formed between the linear runner (11) or an extension (18) adjoining the linear runner (11) and a fastening structure (19) formed for fastening the bear (12) to the linear runner (11), wherein the fastening structure (19) is preferably formed as a wedge or cone segment which can be form- or force-fittingly connected to the bear (12).
12. Forging hammer (1) according to any one of claims 1 to 11, wherein the linear drive (11) comprises a magnet section (23) formed of a plurality of permanent magnets (24, 25) arranged one behind the other in the axial direction and extending in the axial direction, wherein, preferably, the permanent magnets (24, 25) are formed as magnetic ring discs and are fixed, in particular braced, on a piston rod (26) extending through the magnetic ring discs, preferably by fastening elements (28, 29) located on both sides of the magnetic section (23), wherein the linear drive (9) is optionally designed as a tubular linear motor, wherein in extension of the magnetic section (23) a cylindrical extension (17, 18) adjoins one axial end of the linear rotor (11), on or in which the decoupling structure (20, 22) and/or, if dependent on claim 11, the fastening structure (19) is formed.
13. Forging hammer (1) according to claim 12, wherein the permanent magnets (24, 25) are successively magnetised alternately radially and axially in the axial direction (L), wherein optionally laminated sheets, in particular peelable laminated sheets, are arranged between axially successive permanent magnets (24, 25).
14. Forging hammer (1) according to any one of claims 1 to 13, wherein the linear drive (9) comprises a linear motor which is designed as a permanent magnet excited synchronous linear motor, in particular a solenoid linear motor.
15. Forging hammer (1) according to any one of claims 1 to 14, further comprising a housing structure (32) for a or the electric linear motor (9) of the electric linear drive (9), the housing structure (32) being formed as a load-bearing element; has a housing base (33) on which the stator (10) of the linear motor (9) is held, in particular fixed and supported, and, on a side facing the bear (12), comprises one or more stop buffers (29) which are designed in such a way that, in the event of a collision, in particular an extraordinary collision, between the bear (12) and the housing structure (32), a mechanical load caused by the collision for the linear motor (9) is at least attenuated or buffered.

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