Plant and method for assemblying electric motor armatures through winding of metallic tape

Abstract

The invention relates to a plant for the production of electrical armatures such as stators or rotors of motors or electrical generators, the plant comprising: a source store (1); at least one cutting station (2); a separating and forming station (3); a collecting station (5); motorized transport and tensioning means; wherein the cutting station (2) is equipped with at least one laser cutting unit (21), positioned on at least one vertically sliding cutting slide (22), the laser cutting unit (21) comprising a laser head (221) for laser cutting the strip, which is movable along an axis perpendicular to the strip's forward direction in opposite directions over a predetermined stroke length and optionally also in a direction parallel to the said forward direction. The invention also relates to a method for controlling a plant for the production of electrical armatures such as stators or rotors of motors or electrical generators, obtained through laser cutting and winding of a metal strip, enabling specific configurations such as chamfers to make the winding seats better suited to accommodate the windings themselves, thereby increasing the performance of electric motors comprising such armatures.

Description

Plant and method for assemblying electric motor armatures through winding of metallic tapeDESCRIPTION

[0001] The present invention relates to a machine or apparatus for manufacturing components of electric motors , in particular for producing armatures that form the stators or rotors of such electric motors . The control procedures of the machine are also included in a set of operational steps which, in their generic form, can be referred to as a method for constructing or assembling said armatures as speci fied below .

[0002] The present invention also relates to an improved method for producing armatures of electric motors , using the advantages introduced by such a machine , in particular for creating optimi zed geometries of said armatures which enable better support for the windings inserted into them, and consequently better performance of the electric motor due to enhanced mechanical and electromagnetic configurations .

[0003] The apparatus is designed to assemble said armatures starting from material originally stored in a source store where it is present in the form of a semi- finished strip . The apparatus operates on such semi- finished material in a semi-automatic manner, performing, among other operations , cuts or etchings on the strip, and then winding it around a spindle to form said armatures .

[0004] Speci fically, the electric motors to be produced include armatures involved in generating magnetic fieldswith axial flux, armatures which are obtained by winding a strip of known material, which is given a specific shaping, around a rotating spindle to form a structure such as a motor core having a spiral configuration with radial slots.

[0005] Hereinafter, unless otherwise specified, the terms "slot, " "aperture, " "cavity, " and "groove" will be used interchangeably to denote the radial openings obtained or obtainable in the rotor or stator armature of the motor.

[0006] Furthermore, a "tape" of material may also be referred to as a "strip" of material, referring to elements of substantially elongated shape that extend along a longitudinal axis with respect to which the length of the element or of one of its portions can also be defined; transversely to the longitudinal axis, a transverse axis of the element can be identified, where the width of the element, among other dimensions, can be measured, defining a direction of advancement of the element (strip / tape) itself within the apparatus. Along the direction perpendicular to the two axes mentioned, the thickness of the element is defined.

[0007] For the purposes of this description, an electric "motor" may also be regarded as an electric "generator" for the processes and components of interest here, namely the creation of armatures whose use is not restricted to converting electrical energy into mechanical energy or vice versa .

[0008] In its simplest form, axial electric motors and generators essentially comprise a stator and a rotor having a cylindrical shape, with the rotor positioned facing the stator. One method for producing axial flux rotors and stators involves winding a magnetic sheet strip, suitably preformed, around a spindle to form a lamination pack.

[0009] The lamination pack is made in such a way as to feature a certain number of radial slots or slots oriented according to a radial component, of known shape and size, to accommodate the windings of electrical conductors.

[0010] Compared to other types of electric motors, such as radial flux motors, axial flux motors offer specific advantages which are not further discussed here.

[0011] Processes and devices are known for the production of spiral armatures for axial flux motors that perform processing on a origin strip; such processing mainly includes punching the strip and subsequently winding it onto a spindle whose rotational amplitude is chosen so that the wound spiral presents the desired radial slots.

[0012] The precision of the slots is one of the critical aspects for achieving the best possible performance, measured according to various criteria such as thermal, magnetic, or electrical efficiency and / or effectiveness parameters. The known machinery, despite improvements over the years, still has limitations which the applicant aims to overcome at least in part with the present invention.

[0013] A first limitation lies in the fact that punching is performed using a punch tool of specific size chosen for the cut to be made on the strip. Consequently, varying the size of the cut can only be achieved by changing the punch, an operation that may need to be performed manually, requiring the intervention of an operator and resulting in machine downtime. This requires specific punch tools and trained personnel to perform the operation. Alternatively, machines equipped with two or more punches are conceivable, which introduce greater complexity and cost in exchange for overcoming some of the aforementioned limitations.

[0014] Another limitation lies in the flexibility of the machine, i.e., the maximum number of different shapes that can be executed without having to modify and / or redesign new tooling. In a punching machine, the need for an additional new shape entails the design of new tooling suitable for creating the new shape. In a laser system, the geometry of the executable shapes is reprogrammable without having to design new mechanical components and / or make substantial modifications to the machine.

[0015] Another limitation consists of mechanical imperfections in the punched strip, such as burrs and deformations in the cutting area.

[0016] Another limitation lies in the stresses to which the strip is subjected during punching: in addition to the aforementioned deformations, the machine must be equipped with systems for holding the strip and / or for controlling and adjusting the undesired advancement of the strip during cutting .

[0017] Another limitation is the noise level of the punching system compared to laser cutting. This may require noise attenuation measures in certain production environments.

[0018] Another limitation is the minimum achievable distance between two shapes. In punching, the minimum distance between two shapes is often constrained by the size of the punches and the shape of the punch tool. In laser cutting, this distance can be significantly reduced, allowing for closer spacing of shapes.

[0019] A further limitation concerns the precision of the slots obtained when the armature is made. In fact, to achieve slots / grooves / channels with walls that are as straight aspossible ( as shown in the figures ) , it is necessary to increase the distance between the grooves obtained by the cuts applied to the unprocessed strip . These distances must increase as the spiral diameter grows during winding . The alignment of the grooves is critical for the performance of the assembled component . For example , tolerances on high- performance motors are in the range of tens of microns .

[0020] To mitigate this criticality, known machines resort to speci fic measures , such as the retraction of the spindle at the end of each punching step, combined with the winding of the punched strip portion . The spindle is installed on a translatable platform ( e . g . , operated by a motori zed screw) that is progressively retracted during spindle rotation . This retraction movement ensures , on the one hand, that the strip remains orthogonal to the cutting station and tangent to the wound armature portion as the armature diameter increases during winding . On the other hand, it ensures that the grooves of each strip layer forming the spiral are aligned with the grooves of subsequent layers until the armature is fully wound . In this way, the walls o f the armature openings will be straight and not misaligned . Various improvements to this method are known, including speci fic algorithms for calculating the spacing required at each punching step and / or detecting the alignment of overlapping grooves in the spirals during winding . These algorithms can improve the precision o f the obtainable armature but do not appear to resolve the problem entirely and remain limited in their application .

[0021] In the field of forming armatures for electric motors from punched metal strips , an alternative technique is described in EP2675049B1 , which discloses a method and apparatus for forming a core for an electrical machine . Inthis method, a stamped metal strip is wound onto a spindle to form a helical winding that grows in an axial direction of the armature , with windings of constant radius along the entire axial extension of the armature . To properly wind and align the wound tape , it is provided that the diameter of the spindle is increased to apply tension to the wounding strip and subsequently reduced to disengage the laminated core from the spindle . In this solution, the unprocessed strip is cut with a single profile that repeats uni formly along the entire length of the strip required to build the armature . As will be seen later, the technical solution o f this prior art operates very di fferently from the present invention, which provides for winding a spiral of shaped strip around a spindle , growing radially rather than axially, with windings that continuously increase their radial dimension from a radially inner position to a radially outer position . One of the numerous di f ferences compared to EP2675049B1 is therefore that the profile of the radial grooves obtained by winding can be shaped by varying the dimensions of the individual cuts made in the unprocessed strip .

[0022] An alternative solution to stamping or punching involves the use of laser cutting machines , as described in CN106026555 , which discloses a CNC laser cutting system for processing unprocessed metal strips , allowing the creation of shaped bands for industrial applications . However, the document neither teaches nor suggests dynamic adj ustment of the groove profile during cutting, nor does it address the geometric variations of the final product during the winding process .

[0023] Considering these and other limitations , the in-vention aims to improve the production technique for armatures for electric motor components through a plant for the production of electric armatures such as stators or rotors of electric motors or generators . This plant comprises :- a source store provided with a known quantity of unprocessed metal strip to be processed, said source store being preferably in the form of a reel containing said unprocessed strip ;- at least one cutting station for processing said unprocessed strip coming from the source store , where at least one cut is performed on the unprocessed strip according to a predefined shape , generating a shaped strip band and at least one waste strip band;- a separating and forming station for separating the shaped strip band and the waste strip band from the cut processed strip and forming at least one armature , which separating and forming station comprises winding means for winding the shaped strip band around a winding spindle to form the metal spiral of an electric motor armature ;- a collecting station for collecting the waste material , particularly said at least one waste strip band, that is , the portion of the strip not used after the cutting operations performed in said cutting station;- transporting and tensioning means for moving said unprocessed strip and / or portions thereof along a forward direction parallel to the longitudinal direction of the strip, along a path extending from said source store to said cutting station and to said separating, forming stations and to the collecting station; wherein said cutting station is provided with at least one laser cutting unit , positioned on at least one verticallysliding cutting slide , said laser cutting unit comprising a laser cutting head movable along an axis perpendicular to the forward direction of the strip in two opposing directions for a stroke of predetermined length and optionally also in a direction parallel to said forward direction . Additionally, the laser head can be adj usted in a direction orthogonal to the strip to correctly set the focal distance depending on the thickness of the strip .

[0024] The invention also relates to a method of controlling a plant for manufacturing electric motor armatures , preferably for controlling a plant of the type described here , comprising the steps of :- supplying a unprocessed, continuous , metallic strip made of ferromagnetic material ;- performing, in a cutting zone and by means of a laser cutting unit , one or more continuous cuts on said unprocessed strip and along said unprocessed strip, separating a continuous shaped strip band from a waste part of the unprocessed strip, preferably in the form of a waste strip band, in such a way as to create a number of strip openings or grooves mutually spaced according to a predefined criterion;- determining a target number of windings and / or the target length of said shaped strip band necessary to form an electric motor armature ;- winding said shaped strip band to create a spiral composed of a plurality of windings such that the grooves of the shaped strip overlap to form a plurality o f radial slots in the armature ;- detecting the achievement of the target number of windings or the target length currently wound during said winding step ;- interrupting the continuous shaped strip band upon reaching the target number of windings or the target length wound;- attaching to the spiral , by gluing or welding, the end of the shaped strip band created after the interruption in the previous step .

[0025] According to one embodiment , the laser cutting unit performing the cut on the unprocessed strip is translated along a direction parallel to a radial direction of the winding spiral of the shaped strip band . The translation is proportional to the growth of the winding spiral during the winding of the shaped strip band, and it is performed in such a way that the laser cutting unit maintains a constant angle of incidence towards the unprocessed strip in the cutting zone as the radial dimensions of the armature increase during winding .

[0026] An improvement to said method provides that the grooves in the unprocessed strip are generated by advancing the strip along a processing path and / or by moving the laser cutting unit along an axis perpendicular to the forward direction of the strip in two opposing directions for a stroke of predetermined length, optionally also in a direction parallel to said forward direction .

[0027] A further improvement provides that the laser head performs at least one continuous cut extending in the longitudinal direction of the virgin strip, separating the virgin strip into at least two portions , namely a shaped strip band intended to be wound onto a winding spindle to form the electric motor armature and at least one waste strip band to be discarded and optionally subsequently collected for recycling or reuse .

[0028] In a preferred variant , the cutting profile of the laser head is dynamically varied, under the control of a control unit , in such a way as to modi fy the width of the grooves along the virgin strip in one or more portions of the shaped strip band, depending on the geometric speci fications of the armature to be produced .

[0029] A further improvement provides that the grooves of the shaped strip band are made with a rounded geometry at the edges , obtained by dynamically varying the cutting profile of the laser head to modi fy the width of the grooves along speci fic sections , in such a way that :- the bevels are present at the radially innermost and / or outermost corners of the grooves ;- the bevels have a configuration, defined by preset or dynamic parameters , such as to reduce stress concentration points during winding and to optimi ze the distribution of the magnetic flux in the armature .

[0030] Profiles with polar expansions made with bevels are known from document CN105375655A, in a similar technological context but with structures made as standalone entities ( see in particular Figure 1 ) , for example produced by sintering or stamping, and subsequently applied to a base support by gluing or a similar process . Moreover, the document teaches a construction obtained by axial assembly, partially similar to EP2675049B1 , with a series of adj acent layers as shown in Figures 12 , 13 , and 14 . This technique has limitations in terms of complexity in production and assembly of the elements in the finished structure , making its industrial application impractical , less functional , and less economical .

[0031] Such document does not describe a process for producing the stator but focuses mainly on the geometric configurations and magnetic materials used to optimi ze the performance of an axial flux motor .

[0032] Such document describes speci fic configurations , such as the use of soft magnetic cores and permanent magnets arranged in single-layer or multi-layer structures to improve magnetic flux density, but does not speci fy how to produce the stator or which production method to use to achieve the described configurations . There are no references to processes such as laser cutting, winding of metal strips , or dynamic adj ustment of geometries during production .

[0033] Moreover, it is evident even to a person not skilled in the art that the shape of the stator as taught in CN105375655A cannot be obtained by winding a metal strip growing around a spindle , making the concepts inapplicable to the automatic machines subj ect of the present invention .

[0034] As also described below, the configurations therewith described ensure a high-quality electrical armature due to the precision of the cut and the optimi zation of the geometries , with benefits in terms of mechanical and magnetic ef ficiency, waste reduction, and operational costs .

[0035] In particular, but not exclusively, the ability to dynamically vary the cutting profi le of the laser head allows the width of the grooves to be adapted to the geometric speci fications required by the armature . This makes the system suitable for customi zed and multi- format configurations without requiring hardware modi fications .

[0036] In addition to reducing the risk of machining er-rors that could result in non-compliant or unusable materials , the dynamic adj ustment of the cutting process improves the overall quality of the radial slots , ensuring optimal alignment during winding and a de fect- free final armature . In the case of rounded slot geometry, the presence of bevels at the edges , achieved by dynamically varying the cutting profile , evenly distributes mechanical forces during winding, preventing stress concentration points that could cause deformations or cracks .

[0037] Furthermore , the rounded edge configuration reduces the risk of damage to the conductor material or insulation during winding, increasing the durability and reliability of the armature .

[0038] Furthermore , the bevels reduce geometric discontinuities that could interfere with the magnetic flux path . This improves the ef ficiency of the motor or electric generator by reducing magnetic losses and increasing performance . The presence of bevels at the innermost and outermost corners of the grooves enables a seamless geometric transition, enhancing the alignment and stability of the radial slots .

[0039] The capability to integrate the rounded geometry and dynamic cutting variations into the automated process makes the plant highly versatile , suitable for di f ferent types of electric armatures .

[0040] The control unit and laser head work in synergy to ensure precise and continuous adj ustment of the cutting profile , without interruptions in the production process .

[0041] These advantages make the production process unique compared to known technologies , combining precision, automation, and design and production flexibility .

[0042] These and other features and advantages of the present invention will become more apparent from the following description of an embodiment i llustrated in the attached drawings , in which :Figures 1 and 2 show, in di f ferent perspective views , a plant according to the invention;Figure 3a shows a single cutting l ine made on a unprocessed strip ;Figure 3b shows a double cutting l ine made on a unprocessed strip ;Figures 4a and 4b show two armatures obtained from winding the strips in Figures 3a and 3b ;Figure 5 illustrates a detail of the separation phase of the cut virgin strip and winding to form a stator armature ;Figure 6 shows the profiles of two possible shapes of the armature grooves , the second with rounded edges ;Figure 7 illustrates details of a waste band collecting station;Figure 8 shows details of a cutting, separating, and winding station for the strip ;Figure 9 provides a block diagram of the control part of a plant according to the invention;Figure 10a shows a comparison between a radial flux armature and an axial flux armature ;Figure 10b shows an example of an axial flux induction motor structure , with a stator located between a pair of rotors of the type subj ect to the invention;Figure 11 shows a plan view of two strips , shaped withconstant and variable slot width, respectively.DESCRIPTION OF EMBODIMENTS

[0043] Referring to the figures, Figures 1 and 2 present an embodiment of the plant according to the invention. It comprises a source store (1) loaded with a reel (11) containing a known quantity of unprocessed metal strip (9) that is processed within the plant as it passes through various stations until an armature is obtained, along with a certain amount of waste strip collected in a collecting station (5) .

[0044] In the specific case of armatures for electric motors, the invention can be applied to the construction of axial flux motor rotors, as shown in Figure 10b. These motors operate using magnetic fluxes propagating in the axial direction, unlike the more common radial flux motors, as compared in Figure 10a.

[0045] Along the path the strip takes from the reel (11) within the plant, it is sequentially processed by several stations performing specific operations. Among these, the cutting station (2) is a laser cutting station where at least a single cut (90) (Figure 3a) or double cut (90' and 90' ' ) (Figure 3b) are performed on the unprocessed strip (9) according to a predefined shape, so as to separate the unprocessed strip and create a shaped strip band (91 or 91' ) and at least one waste strip band (92 or 92' and 92' ' ) .

[0046] The shaped strip band is formed so that, when wound, it can constitute the armature shown in Figures 4a or 4b, and a skilled person will easily understand that various shapes chosen according to the resulting armature form fall within the scope of this invention.

[0047] Still focusing on Figures 4a and 4b, it can be observed that the armatures correspond to single- or doublepolarity structures; the double-polarity form in Figure 4b is wound starting from a strip with double cutting shape, which can be made with a cutting unit performing a double pass or with a double-head laser cutting unit, according to known technologies not further described here.

[0048] The cutting station (2) is equipped with at least one laser cutting unit (21) , positioned on a cutting slide (22) sliding vertically along a Z direction (Figure 2) and capable of movements also along the strip's advancement direction Y, i.e. the longitudinal direction of the strip itself, and along an X direction orthogonal to the previous directions and transverse to the strip.

[0049] The laser cutting unit (21) comprises a laser head (221) for laser cutting the strip, which performs movements along the X-axis, perpendicular to the strip's advancement direction Y, in two opposing directions of displacement. The length of the transverse cuts or the stroke along the X-axis is predetermined and controlled by a control unit (1000) , better described later.

[0050] Hereafter, reference will be made to a laser head capable of performing cuts in multiple directions. However, this does not exclude the possibility that the cutting unit may include two or more laser heads, positioned, for example, at different locations along the longitudinal stroke of the unprocessed metal strip, which may operate sequentially or in parallel. These laser heads may be specialized for specific tasks (e.g., performing cuts in a particular direction and / or having different intensities) or may all be configured in the same mode.

[0051] The 1 aser head 221 may, thanks to motorized organs mounted on the slide 22, also perform movements along a direction Y parallel to the said forward direction, i.e., the longitudinal direction of the unprocessed metal strip 9. Alternatively, it can be provided that longitudinal cutting may be performed by keeping the laser head 221 stationary and operational at a specific transverse position, while advancing the strip for the portion necessary to execute the longitudinal cutting required to form the continuous cutting line (90) and thus the shaping of the strip.

[0052] Overall, the plant is capable of performing at least one continuous cut 90, as well as other cuts, such as 90' and 90' ', extending in the longitudinal direction of the unprocessed metal strip 9, separating it into at least two portions, corresponding to a shaped strip band 91 destined to be wound onto the winding spindle 32 to form the armature 4 of an electric motor, and at least one waste strip band 92 to be discarded and optionally collected in the subsequent collecting station 5.

[0053] To optimize the operation of the laser head, the cutting station 2 is provided with a pulley or drum 64 positioned on the slide 22 in such a way as to keep the strip horizontal, or more generally parallel, to the sliding direction of the head and orthogonal to the vertical sliding axis. The strip is tensioned between the organ 64 and the edge of the strip winding around the armature 4, i.e., the area where the edge of the shaped strip band 90 or 90' begins to form the winding spiral 41 of the armature (Figure 5) .

[0054] The plant may also be configured such that the control unit 1000 commands the laser head 221 to perform an additional cut to interrupt the shaped strip band 91 upon reaching a predetermined dimension of the armature 4 woundon the winding spindle 32 .

[0055] Alternatively, the plant may integrate a speci fic unit for interrupting the shaped strip band, with the control unit 1000 configured to command this interrupting unit to sever the shaped strip band 91 upon reaching the predetermined si ze of the armature 4 wound on the winding spindle 32 .

[0056] The separating and forming station 3 ) is responsible for forming the armature by winding the shaped strip band previously processed in the cutting station 2 . Referring also to Figure 8 , the strip is wound around a spindle 32 , moved by motori zed winding organs 31 , which are commanded by the control unit 1000 . The spindle includes removable means for gripping the strip during the building of the armature , and means for ej ecting the wound armature , for example by means of an axial ej ector 36 capable of applying an ej ection force along the axial direction of the armature after it has been completed and released from the spindle .

[0057] Still referring to Figure 8 , it is noted that in station 3 the unprocessed metal strip 9 , previously cut with at least one cutting line 90 , is separated into two parts : the shaped strip band 91 and the waste strip band 92 . The representation is schematic and does not show the progressive spacing of the grooves 95 ) Figure 3a ) , which are essential for allowing the formation of grooves 42 with substantially flat internal profiles and at least partially oriented in a radial direction . Figure I l a provides a view of the strip where the grooves , of constant width, are progressively spaced along the winding path of the strip . This representation is illustrative , and in practice , the grooves are spaced with an interval that increases as a function of the radius and the state of winding .

[0058] The winding means 31 are regulated to maintain the correct tension of the strip around the spindle and activated in coordination with the cutting operations of the unprocessed metal strip .

[0059] The station 3 ) s also equipped with a finishing station 35 for securing the free terminal end of the shaped strip band 91 or 91 ' to the completed armature 4 . This finishing station 35 preferably operates by gluing or a similar chemical and / or physical action on a portion of the shaped strip band that is adhered to the underlying spiral after the band itsel f has been severed upon reaching the desired radial dimension . Since the strip is made of ferromagnetic material for operation with appropriate magnetic fluxes , gluing is preferred over welding to avoid short circuits between the windings and / or grounding connections of the armature when the electric motor is assembled .

[0060] Downstream of station 3 there is a tensioning station 8 comprising a tensioning assembly 82 , for example composed of two counter-rotating pres sing drums or pulleys , at least one of which is motori zed . This assembly receives the waste strip band 92 , guiding it towards the downstream station, even in the event of its interruption, while keeping it tensioned to facilitate its separation from the shaped strip .

[0061] This feature is optional and may be implemented in other forms . In the embodiment described here , an additional slide 81 is present , sliding vertically, and it is preferably actuated to ensure that the waste strip band remains substantially hori zontal along the path extending from the pulley 64 to the strip winding edge around the armature 4 .

[0062] Subsequently, the plant includes a collecting station 5 ( fig . 7 ) where the waste strip band 92 is collected and wound onto a collecting reel 56 . The collecting station 5 comprises a collecting store 51 , such as a winding reel 53 supported in rotation by a motori zed mandrel or winding spindle 512 , and emptying means for unloading the collecting store upon reaching a certain amount of material . The emptying means may consist of an ej ection system 511 capable of applying an axial ej ection force on the reel 53 , guiding it along the removal direction from the winding spindle 512 .

[0063] The collecting station 5 is equipped with pulling organs for the waste strip band exiting the mobile tensioning station 8 , in particular a calender system 52 and rotary pressing cylinders 531 and 532 , which cooperate with a motori zed pulling system 54 for moving the waste strip band towards the collecting reel 56 .

[0064] Between the two cylinders 531 and 532 , a cutting unit 55 for the waste strip band i s interposed . This cutting unit is used to sever the waste strip band when it is necessary to remove the winding reel , typically when it has been loaded with a certain amount of material . The configuration with the cutting unit positioned between the two pressing cylinders allows the waste strip to be cut ( once its movement has been halted) and subsequently held in the first cylinder 531 while the severed part is advanced over the second cylinder towards the loaded winding reel . After replacing the loaded winding reel with a new empty reel , the waste strip band can be advanced from the first cylinder 531 to the second cylinder and to the new reel to resume the plant ' s operation .

[0065] With reference to figure 9 , the plant includes a control unit 1000 that acts on one or more parts of the plantitsel f to manage its operation, al lowing it to operate in at least partially automated mode . The control unit 1000 includes , in addition to common functional modules such as power supply devices , human-machine and machine-machine interfaces , a processing unit 1100 and at least one memory 1200 , in which a software program is loaded to manage the motori zed organs present in the various stations so as to command the di f ferent operations for the production of armatures and recovery of waste , including the advancement of the unprocessed metal strip and the movement and activation of the laser cutting unit 21 to create a plurality of grooves 95 on the unprocessed metal strip 9 having dimensions and positions designed to form the radial slots 42 of the armatures 4 upon the winding of the spiral 41 of the shaped strip band 91 around the winding spindle 32 , an operation also at least partially commanded and supervised by the control unit .

[0066] The control unit operates on the various stations of the plant , from 1 to 8 , supervising and / or controlling the operations of the plant .

[0067] With reference to figure 6 , it shows two possible implementations of an axial flux stator armature in a frontal view of portions of the same . The upper figure can be referred back to the armatures illustrated earlier, such as those in figure 4a and figure 5 . It can be seen from this that the radial slots 42 develop with a substantially par- allelepipedal shape , whose cross-section corresponds to the shape of the grooves 95 that the laser head 221 cuts into the unprocessed strip 9 .

[0068] Compared to armatures produced by previously known machines , the invention allows the production of radial slots with improved wall uni formity : laser cutting enables increased precision of the grooves , in particular the distancebetween them when created on the unprocessed metal strip . This precision is crucial to ensure that the grooves of two overlapping windings are perfectly aligned . Moreover, the combination of laser cutting with the spindle 32 , operated by motori zed winding organs 31 controlled by the control unit 1000 , eliminates the need for translating the spindle itsel f to vary the distance between the grooves , as is required in known machines .

[0069] Moreover, comparing the two representations in figure 6 , it can be observed that , thanks to this plant , it is possible to achieve rounded edges at the ends of the slots or, more generally, to vary the cutting profile of the laser head 211 in such a way as to modi fy the width of the grooves 95 in one or more portions of the shaped strip band that forms the armature 4 . The variation in groove width is achieved through an algorithm loaded into the memory of the control unit 1000 , which calculates the adj ustment in real time based on the geometric parameters of the forming spiral . The plant thus allows the production of armatures with di fferent geometric configurations without manual modi fications or tool changes .

[0070] In one embodiment , the algorithm may provide instructions for the control unit 1000 that enable it to receive input information regarding the shape of the grooves and automatically generate control signals for the laser head and the various components of the armature production plant based on this information .

[0071] Speci fically, according to this method for manufacturing an armature , the width of the grooves is increased in the strip sections that form a certain number of radially inner and / or radially outer windings at the terminal ( outerand / or inner) part of the windings, following a known progression to create a chamfer at the radially innermost edges 43 and / or radially outermost edges 43' ' of the armature slots, with a predetermined chamfer radius R.

[0072] The armature thus obtained provides significant advantages, such as:

[0073] Mechanical advantages, for example the reduction of mechanical stresses on the windings, as the rounded edges better distribute mechanical forces during the coil winding on the shaped strip, reducing stress concentration points at sharp edges.

[0074] This reduces the risk of deformations or crack- ing / micro-f racturing in the material, improving the durability of the armature.

[0075] Consequently, damage is prevented as the presence of rounded edges reduces friction between successive layers of the wound strip, avoiding damage to the insulation of the conductor wires or the ferromagnetic material.

[0076] Addit ionally, the winding process is improved, as the rounded geometry facilitates the precise positioning of conductors during winding, preventing misalignments and improving the overall quality of the armature.

[0077] The reduction of mechanical stresses and the greater uniformity of magnetic flux can help decrease vibrations and noise during operation.

[0078] Further advantages arising from this configuration are achieved from a magnetic performances: for example the reduction of magnetic losses as the rounded edges create a more uniform path for the magnetic flux, reducing losses caused by localized dispersion or saturation and therebyallowing improved electromagnetic performance.

[0079] Furthermore, a rounded edge geometry reduces discontinuities in the radial slot geometry, optimizing the conduction of magnetic flux through the armatures.

[0080] From a manufacturing perspective, the rounded shape is achieved directly during the laser cutting process, avoiding the need for subsequent mechanical treatments to round the edges. Laser processing ensures precise and uniform chamfering across all grooves, improving process repeatability and reducing defects.

[0081] Still in terms of manufacturing benefits, the reduction of mechanical stresses and greater geometric precision lower the risk of defects in the finished product, contributing to reduced production waste.

[0082] Additionally, a rounded-edge geometry increases the structural strength of the armature, making it more stable during operation at high speeds and loads, thus ensuring greater integrity and longer service life of the produced armature .

[0083] From an application standpoint, the method is easily usable in various contexts, and the rounded-edge geometry is particularly useful for armatures of high-performance motors, such as those used in automotive, industrial, or aerospace applications.

[0084] It is therefore clear that the rounded-edge geometry improves the mechanical, magnetic, and production performance of the armature, reducing stresses and optimizing system efficiency. This approach not only ensures greater durability and reliability but also represents a cost-effective solution due to the simplification of production pro-cesses . It becomes evident that such an armature configuration requires instead signi ficantly complicates punches-op- erating machines , as it requires additional equipment .

[0085] In one variant , the plant further includes a unit for interrupting the shaped strip band 91 , and the control unit commands this interruption unit to sever the shaped strip band 91 upon reaching the desired si ze of the armature 4 wound on the spindle . Alternatively, the interruption of the shaped strip band is performed by the laser cutting head 211 under the command of the control unit .

[0086] In another variant , the invention introduces an additional finishing station 35 for securing the free terminal end of the shaped strip band 91 to the wound armature . Preferably, this station operates by gluing the terminal section of the shaped strip band after cutting . Less preferably, but still within the scope of the invention, the finishing station operates by welding the free end of the shaped strip band to the wound body of the armature .

[0087] In yet another variant , the plant includes a collecting station 5 for the waste strip bands 92 , positioned downstream of the separating and forming station 3 in the strip ' s processing path within the plant . The collecting station includes a collecting store 511 , such as a winding reel supported in rotation by a motori zed mandrel or winding spindle 512 , preferably controlled by the plant ' s control unit . The collecting store also includes means for removing the collected material once a known amount is reached, as in the case of the available volume of the collecting reel being filled, with an ej ection system 512 for the reel ' s replacement by an operator .

[0088] The collecting station 5 is advantageouslyequipped with pulling organs for the strip, such as a calender system and rotary pressing cylinders 531 , which cooperate with a motori zed pulling system to drive the waste strip band . The pulling force faci litates the advancement o f the waste strip band toward the scrap reel and also aids in the advancement and tensioning of the unprocessed metal strip through the previous stations from which the waste strip originates . Thanks to the calender, it is possible to adj ust the force between the rotating cylinders and the strip required for its movement .

[0089] The collecting station 5 also includes a cutting unit 55 for the waste strip band, which is activated when the collecting store is full , allowing it to be emptied before resuming collection operations with an empty store .

[0090] Advantageously, the cutting unit 55 is positioned between two pressing cylinders along the waste strip band ' s path, so as not to interrupt the tensioning action towards the separating and forming station 3 or towards the collecting store when the waste strip band is severed .

[0091] Once the collecting store 511 has been emptied by ej ecting the waste reel , the pulling organs 531 ensure it is replenished by advancing the edge of the waste strip band previously severed by the cutting unit 55 toward the mandrel or winding spindle .

[0092] In one embodiment , the plant includes a j oining station 7 to j oin the terminal end of the strip when it is depleted in the store 1 of unprocessed metal strip with the starting end of a new strip made available after replenishing the store . To this end, the spl icing station includes a j oining unit 71 interposed between two tensioning organs , such as two motori zed rollers or pulleys 61 and 62 . When theplant is stopped, the second pulley 62 can hold the terminal end of the depleted unprocessed metal strip, while an operator manually or semi-automatical ly replenishes the store ( e . g . , by placing a new unprocessed strip reel on its unwinding mandrel ) and positions the starting end of the new strip in the first pulley 61 . In this way, the operator only needs to weld the two ends of the old and new strips using the splicing unit 71 without manual ly threading the new strip along the entire line .

[0093] Optionally, the plant includes at least one sensor to determine the status of the source store and / or the approaching depletion of the unprocessed metal strip to be processed .

[0094] Thus , the plant is capable of operating according to the following method :Determine the depletion of the unprocessed metal strip 9 in the store 1 ;Stop the advancement of the unprocessed metal strip 9 when its terminal end has been released from the first pulley 61 but is still engaged in the second pulley 62 ;Replenish the store with a new unprocessed metal strip ;Engage the starting end of the new unprocessed metal strip in the first pulley 61 ; j oin the terminal end of the previous strip to the starting end of the new strip using the j oining unit 71 .

[0095] With the described method, it is possible to continue producing axial motor armatures when the strip is depleted from the source store , j oining the strip . However, this results in an armature made with j oined strip, which may exhibit reduced performance due to imperfections in theshaped strip band forming the wound spiral .

[0096] I f such imperfections negatively impact the armature ' s performance beyond acceptable levels , the machine can operate di f ferently, as follows :Determine the depletion of the strip in the store ;Stop the cutting and winding process of the armature ;Discard the wound portion of the armature ;Replenish the source store ;Load the new unprocessed metal strip from the replenished store into the plant ;Resume the cutting and winding process .Or alternatively :Determine the depletion of the strip in the store ;Stop the cutting and winding process of the armature and simultaneously stop the advancement of the unprocessed metal strip 9 when its terminal end has been released from the first pulley 61 but is still engaged in the second pulley 62 ;Discard the wound portion of the armature ;Replenish the source store ;Load the new unprocessed metal strip from the replenished store into the plant ;Engage the starting end of the new unprocessed metal strip in the first pulley 61 ;Join the terminal end of the previous strip to the starting end of the new strip using the splicing unit 71 ;Resume the cutting and winding process only when the section of the strip containing the splice has passed theseparating station 3 and subsequently entered the scrap store 511.

[0097] Throughout the description, similar reference numbers may be used to identify similar elements.

[0098] While the various aspects of the embodiments are presented in the drawings, the drawings are not necessarily to scale unless specifically indicated.

[0099] It will be readily understood that the components of the embodiments, as generally described here and at least partially illustrated in the attached figures, may be arranged and designed in a wide variety of different configurations .

[0100] The refore, the following detailed description of various embodiments, as represented in the figures, is not intended to limit the scope of the present description but is merely representative of some possible embodiments.

[0101] The described embodiments should be considered in all respects as illustrative and not limiting.

[0102] All changes that fall within the meaning and range of equivalence of the claims should be encompassed within their scope.

[0103] References throughout this description to features, advantages, or similar language do not imply that all features and advantages that may be achieved with the present invention must be or are present in any single embodiment of the invention.

[0104] Rather, the language referring to features and advantages is intended to indicate that a specific feature, advantage, or characteristic described in connection with a particular embodiment is included in at least one embodimentof the present invention.

[0105] Consequently, discussions of features and advantages and similar language throughout this description may, but are not required to, refer to the same embodiment.

[0106] Furthermore, the features, advantages, and claimed characteristics of the invention may be combined in any suitable manner in one or more embodiments.

[0107] A person skilled in the art will recognize, in light of this description, that the invention may be implemented without one or more of the specific features or advantages of a particular claimed embodiment.

[0108] In other cases, additional features and advantages may be identified in certain embodiments that may not be present in all embodiments of the invention.

[0109] References throughout this description to "an embodiment, " "a variant, " "an implementation, " or similar language mean that a particular function, structure, or characteristic described in connection with the mentioned embodiment is included in at least one embodiment of the present invention .

[0110] Consequently, references to "an embodiment, " "a variant, " and similar language throughout this description may, but are not required to, refer to the same embodiment.

[0111] The components of the embodiments, as generally described in this document and illustrated in the accompanying figures, may be utilized and designed in a wide variety of different configurations. Therefore, the following more detailed description of various embodiments, as represented in the figures, is not intended to limit the scope of the present description but is simply representative of someembodiments .

[0112] All changes that fall within the meaning and scope of equivalence of the claims are to be encompassed within their scope .

[0113] Although the steps of the methods herein are shown and described in a particular order, the order of steps of each method may be altered such that some operations are performed in a di f ferent order and / or so that some operations may be performed, at least in part , simultaneously with other operations .

[0114] It should be noted that at least some of the operations for the methods may be implemented using software instructions stored on a computer-readable storage medium for execution by a computer .

[0115] For example , one embodiment of a computer program product includes a computer-readable storage medium storing a computer-readable program which, when executed on a computer, causes the computer to perform operations as described herein .

[0116] Furthermore , embodiments of at least portions of the invention may take the form of a computer program product accessible from a computer-usable or computer-readable medium providing program code for use by or in connection with a computer or any instruction execution system .

[0117] For the purposes of this description, a computer- usable or computer-readable medium may be any apparatus that can contain, store , communicate , propagate , or transport the program for use by or in connection with the system, apparatus , or device which executes instructions .

[0118] The computer-usable or computer-readable mediummay be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium.

[0119] Examples of a computer-readable medium include a semiconductor or solid-state memory, magnetic tape, a removable computer diskette, random access memory (RAM) , readonly memory (ROM) , a magnetic disk, and an optical disk.

[0120] Current examples of optical disks include a compact disk read-only memory (CD-ROM) , a compact disk read / write (CD-R / W) , a digital versatile disk (DVD) , and a Blu-ray disk.

[0121] In the description above, specific details of various embodiments have been provided.

[0122] However, some embodiments may be implemented with fewer than all these specific details.

[0123] In other cases, certain methods, processes, components, structures, and / or functions are described not fully but only with the minimum detail necessary to understand the various embodiments of the invention, for the sake of brevity and clarity.

[0124] Although specific embodiments of the invention have been described and illustrated, the invention should not be limited to the specific forms or arrangements of parts so described and illustrated.

[0125] It is nonetheless evident that the invention should not be considered limited to the particular arrangements illustrated above, which constitute only exemplary embodiments thereof, and that various modifications are possible, all within the reach of a person skilled in the art,without departing from the scope of protection of the invention itself, which is defined by the claims that follow.

Claims

CLAIMS1. A plant for the production of electrical armatures such as stators or rotors of electric motors or generators, which plant comprises:- a source store (1) provided with a known quantity of unprocessed metal strip (9) to be processed, said source store being preferably made in the form of a reel (11) containing said unprocessed metal strip;- at least one cutting station (2) for processing said unprocessed metal strip (9) coming from the source store (1) , where at least one cut (90; 90' ; 90' ' ) is performed on said unprocessed metal strip (9) according to a predefined shape, generating a shaped strip band (91) and at least one waste strip band (92; 92' ; 92' ' ) ;- a separating and forming station (3) for separating the shaped strip band (91) and the waste strip band (92) from the cut unprocessed metal strip (9) and for forming at least one armature (4) , which separating and forming station (3) comprises winding means (31) for winding the shaped strip band (91) around a winding spindle (32) to form the metal spiral (41) of an electric motor armature ;- a collecting station (5) for the collection of the waste material, and in particular of said at least one waste strip band (92; 92' ; 92' ' ) , or of the portion of unprocessed metal strip (9) not used after the cutting operations performed in said cutting station (2) ;- motorized conveying and tensioning organs for moving said unprocessed metal strip (9) and / or portions thereof in a forward direction parallel to the longitudinal direction of the strip, along a path extendingfrom said source store (1) to said cutting station (2) and to said separating and forming stations (3) and the collecting station (5) ;- wherein said cutting station (2) is provided with at least one laser cutting unit (21) , positioned on at least one vertically sliding cutting slide (22) , said laser cutting unit (21) comprising a laser head (221) for laser cutting of the strip, movable along an axis perpendicular to the forward direction of the strip in two opposing directions of displacement for a stroke of predetermined length and optionally also in a direction parallel to said forward direction,- wherein a control unit (1000) of the plant or at least of part of it is provided, which control unit (1000) comprises a processing unit (1100) and at least one memory (1200) in which a software program is loaded to control said motorized organs present in the various stations, so as to command the advancement of the strip and also control the laser cutting unit (21) to create a plurality of grooves (95) in the unprocessed metal strip (9) , of such size and position as to form the radial channels (42) of the armatures (4) as a result of winding the spiral (41) of the shaped strip band (91) around the winding spindle (32) .

2. A plant according to claim 1, wherein the control unit (1000) configures the plant such that the laser head performs at least one continuous cut (90; 90', 90' ' ) extending in the longitudinal direction of the unprocessed metal strip (9) , separating the unprocessed metal strip into at least two portions, namely a shaped strip band (91; 91' ) intended to be wound onto the winding spindle (32) to form the electric motor armature, and atleast one waste strip band (92; 92', 92' ' ) to be discarded and optionally collected in the collecting station (5) for the waste strip.

3. A plant according to one or more of the preceding claims, wherein the cutting slide (22) on which the laser cutting unit (21) is positioned is provided with motorized lifting organs (221) , the cutting and forming station (2) comprises at least one movable guiding and tensioning organ of the unprocessed metal strip (64) , and the control unit (1000) commands such motorized lifting organs (221) to vary the position of the cutting slide (22) in a manner directly proportional to the variation of the radial dimension of the armature (4) being formed during the process of winding the metal spiral (41) onto the winding spindle (32) .

4. A plant according to claim 3, wherein the control unit(1000) commands the positioning and movement of the cutting slide (22) and the positioning and movement of the at least one movable guiding and tensioning organ (64) of the unprocessed metal strip (9) such that the unprocessed metal strip (9) tensioned between said movable organ (64) and the strip winding edge around the armature (4) , i.e., the area where the edge of the shaped strip (90; 90' ) begins to form the winding spiral (41) of the armature, remains substantially horizontal and perpendicular to the laser beam emitted by the cutting laser head (211) throughout the winding process and during the growth of the armature (4) on the winding spindle (32) .

5. A plant according to one or more of the preceding claims, wherein the control unit (1000) is configured to vary the cutting profile of the laser head (211) to change the width of the grooves (95) obtained in the unprocessedmetal strip (9) in one or more portions of the shaped strip band (92; 92', 92' ' ) forming the armature (4) .

6. A plant according to the preceding claim, wherein the control unit (1000) is configured to increase the width of the grooves in the strip sections forming a certain number of radially inner and / or outer windings at the outer and / or inner end of the winding according to a known progression to generate a bevel at the radially innermost (43) and / or radially outermost (43' ' ) edges of the armature's grooves, with a predetermined bevel radius R.

7. A plant according to at least one of the preceding claims, which alternatively: further comprises an interrupting unit (55) for the shaped strip band (91; 91', 91' ' ) , wherein, preferably, the control unit (1000) is configured to command said interrupting unit (55) to interrupt the shaped strip band (91; 91', 91' ' ) upon reaching a predetermined dimension of the armature (4) wound on the winding spindle (32) ; or :- is configured such that the control unit (1000) commands the laser head (221) of the separating and forming station (2) to perform an additional cut to interrupt the shaped strip band (91; 91', 91' ' ) upon reaching a predetermined size of the armature (4) wound on the winding spindle (32) .

8. A plant according to at least one of the preceding claims further comprising a finishing station (35) for attaching the free terminal end of the shaped strip band (91) to the wound armature (4) , which finishing station (35)preferably comprises means for chemical and / or physical adhesion of the terminal portion of the shaped strip to the wound body of the armature (4) .

9. A plant according to at least one of the preceding claims further comprising a collecting station (5) for the waste strip bands (92; 92', 92' ' ) located downstream of the separating and forming station (3) along the strip processing path in the plant, which collecting station (5) comprises a collecting store (51) , such as a winding reel supported in rotation by a motorized reel or winding spindle (512) , and emptying means (512) for emptying the collecting store (51) .

10. A plant according to claim 9, wherein the collecting station (5) is equipped with pulling organs for the waste strip bands (92; 92', 92' ' ) , comprising a calender system (52) and rotary cylinder pressers (531; 532) that cooperate with a motorized pulling system (54) to move the waste strip band and optionally a cutting unit (55) for the waste strip band, preferably positioned between two pressing cylinders (531, 532) along the path of the waste strip band ( 92 ; 92 ' , 92 ' ' ) .

11. A plant according to at least one of the preceding claims further provided with a joining station (7) configured to join the terminal end of the depleted unprocessed metal strip with the initial end of a new unprocessed metal strip, maintaining the continuity of the etching and winding process, which joining station (7) is arranged along the path of the unprocessed metal strip (9) downstream of the source store (1) and includes a joining unit (71) interposed between two dragging organs of the unprocessed metal strip, such as two motorized rollers or pulleys (61, 62) .2 . A method for producing electrical armatures such as stators or rotors of electric motors or generators using a plant according to one or more of the preceding claims , which method comprises the steps of :- supplying an unprocessed, continuous , metallic strip made of ferromagnetic material ;- performing, in a cutting zone and by means of a laser cutting unit , one or more continuous cuts on said unprocessed metal strip and along said unprocessed metal strip, separating a continuous shaped strip band from a waste part of the unprocessed metal strip, preferably in the form of a waste strip band, in such a way as to create a number of mutually spaced openings or grooves in the strip according to a predefined criterion;- determining a target number of windings and / or the target length of said shaped strip band necessary to form an electric motor armature ;- winding the said shaped strip band to create a spiral composed of a plurality of windings , where the grooves of the shaped strip are provided at predetermined distances between consecutive grooves along the axial extension of the strip, such that the grooves of the shaped strip overlap to form a plurality of radial channels of the armature ;- detecting the reaching of the target number of windings or the target length currently wound in said winding step ;- interrupting the continuous shaped strip band upon reaching the target number of windings or the target length wound;- binding to the spiral , by gluing or welding, the endof the shaped strip band created after the interruption in the previous step.

13. A method according to claim 12, wherein:- the laser cutting unit performing the cutting on the unprocessed metal strip is translated along a direction parallel to a radial direction of the winding spiral of the shaped strip band;- the translation is proportional to the growth of the radial dimension of the winding spiral during the winding of the shaped strip band; so that the laser cutting unit maintains a constant angle of incidence towards the unprocessed metal strip in the cutting zone as the radial dimensions of the spiral increase during winding.

14. A method according to claim 12 or 13, characterized in that the cutting profile of the laser head (211) is dynamically varied to change the width of the grooves (95) along the unprocessed metal strip (9) in one or more portions of the shaped strip band (92; 92', 92' ' ) , based on the specific geometries of the grooves of the armature (4) to be produced.

15. A method according to claim 14, characterized in that the grooves (95) of the shaped strip band (92; 92', 92' ' ) have radial lateral fronts extending along curved and / or inclined lines relative to the longitudinal axis of the strip and, in particular, are made with a rounded geometry at the edges (R) , obtained by dynamically varying the cutting profile of the laser head (211) to change the width of the grooves along specific sections, such that : the bevels are present at the radially innermostand / or outermost corners of the grooves (95) ; the bevels have a configuration that reduces stress concentration points during winding and optimizes the distribution of the magnetic flux in the armature (4) .

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