Method for making an electric wire coil on a ferromagnetic core and associated winding apparatus

Abstract

A method for making an electric wire coil (A) of at least one wire (C) around a ferromagnetic core (B) comprising: a step of arranging a ferromagnetic core (B) on a support (3) which is rotatable about a rotation axis (Y), a step of coupling the at least one wire (C) to the ferromagnetic core (B), a step of dispensing the at least one wire (C), a step of rotating, in coordination with the dispensing step according to a predefined rule of motion, the ferromagnetic core (B) to create turns around the ferromagnetic core (B), wherein it comprises, furthermore, a step of adjusting the position of the at least one wire (C) around the ferromagnetic core (B), by virtue of respective position adjusting means (4) and compressing means (5), wherein the position and mutual distance between the position adjusting means (4) and the compressing means (5) are variable as a function of the rule of rotary motion of the ferromagnetic core (B).

Description

[0001] METHOD FOR MAKING AN ELECTRIC WIRE COIL ON A FERROMAGNETIC CORE AND ASSOCIATED WINDING APPARATUS

[0002] The present invention relates to a method for making an electric wire coil on a ferromagnetic core and also to an associated apparatus designed for making an electric wire coil on a ferromagnetic core which operates in accordance with the provisions of the method.

[0003] Making electric wire coils on ferromagnetic cores is necessary for the production of electrical machines (generators, motors, transformers). In some cases, the currents circulating on the coils are so high that they require the use of conductor wires having large cross-sections (for example, on the order of 100 mm2and even higher). When conductor wires with large crosssections are used, phenomena of springback thereof to their original shape may occur after they have been arranged on the ferromagnetic core: this causes irregularities in the shape and position of some turns of the coil that compromise their compliance with design standards.

[0004] It is known to resort to means for guiding the conductor wire during its deposition on the ferromagnetic core that favor its correct and ideal placement but cannot exclude possible springback.

[0005] To overcome this drawback, prior art document No. JP2015228393A describes a coil manufacturing apparatus provided with two pressing rollers coupled to a same movement element. The core, fixed on a rotatable support, faces an assembly for feeding the conductor wire, which is forced elastically by the rollers onto the surfaces of said core. Both rollers are driven by a same actuator, to which they are coupled with the interposition of a respective elastic element.

[0006] The actuator ensures that both rollers are always at a predefined distance from the core (regardless of the shape thereof); contrast to springback of the conductor wound around the core is instead determined by the elastic force (applied by virtue of the presence of the spring interposed between each roller and the common actuator) with which each roller is pushed onto said wound conductor.

[0007] The pressure applied by the rollers to the coil (to lock the turns of conductor and prevent a respective springback) is such as to press the turns thereon, entrusting the task of arranging the turns correctly to the correct alignment between the conductor dispenser and the core.

[0008] Using the device according to prior art document No. JP2015228393 A reduces the risk that the springback of the conductor may affect the quality and stability of the coil on the ferromagnetic core, but the correct positioning of the electric conductor during the step of generating the turns cannot be ensured.

[0009] This aspect is important, however, since the compactness of the coil, determined by the arrangement of the contiguous turns, is a key parameter in ensuring the presence of sufficient current density. In particular, for the production of coils with very high current densities, it is known to resort to conductor wires with rectangular cross-sections, so that the minimum amount of void is interposed between each turn and the contiguous one (the flat lateral surfaces of the contiguous turns are juxtaposed).

[0010] Achieving such a result with the apparatus according to prior art document No. JP2015228393A is in practice extremely difficult and necessarily requires the presence of an operator to check and, if necessary, correct the position of the turns (compacting them, so as to minimize the voids interposed between them).

[0011] The aim of the present invention is to solve the above problems by proposing a method for making an electric wire coil on a ferromagnetic core that allows to provide optimal compaction of the turns while avoiding springback phenomena of the wound conductor.

[0012] Within the scope of this aim, an object of the invention is to propose a method for making an electric wire coil on a ferromagnetic core that does not require the presence of operators to control operation and for possible correction of turn positioning errors.

[0013] Another object of the invention is to propose a method for making an electric wire coil on a ferromagnetic core that is also suitable for application with conductors having a rectangular (or generically polygonal) crosssection, regardless of their arrangement on the core.

[0014] Another object of the invention is to propose an apparatus designed to make an electric wire coil on a ferromagnetic core suitable for providing compact coils juxtaposed against all surfaces of the ferromagnetic core.

[0015] Another object of the invention is to propose an apparatus designed to make an electric wire coil on a ferromagnetic core that does not require the presence of operators to control operation and for possible correction of turn positioning errors.

[0016] Another object of the invention is to propose an apparatus designed to make an electric wire coil on a ferromagnetic core that can also operate with conductors having a rectangular (or generically polygonal) cross-section, regardless of their arrangement on the core.

[0017] A further object of the present invention is to provide a method for making an electric wire coil on a ferromagnetic core and an apparatus designed to make an electric wire coil on a ferromagnetic core that have a low cost, are relatively simple to provide in practice and of assured application.

[0018] This aim and these objects are achieved by a method for making an electric wire coil on a ferromagnetic core according to claim 1.

[0019] This aim and these objects are also achieved by means of an apparatus designed for making an electric wire coil on a ferromagnetic core according to claim 7.

[0020] Further characteristics and advantages of the invention will become better apparent from the description of a preferred, but not exclusive, embodiment of the method for making an electric wire coil on a ferromagnetic core and of the apparatus designed to make an electric wire coil on a ferromagnetic core, illustrated by way of non-limiting example in the accompanying drawings, wherein:

[0021] Figure 1 is a schematic side view of a possible embodiment of a system comprising an apparatus designed to make an electric wire coil on a ferromagnetic core according to the invention;

[0022] Figure 2 is a schematic axonometric view of a possible embodiment of a part of the apparatus according to the invention;

[0023] Figure 3 is a schematic axonometric view of a possible embodiment of an apparatus according to the invention in an inactive configuration with a completed coil;

[0024] Figure 4 is a schematic axonometric view of the apparatus in the configuration of Figure 3, with the ferromagnetic core on which the coil is arranged partially rotated;

[0025] Figure 5 is a schematic axonometric view of the apparatus of Figure 3 in the configuration of Figure 3 from a different viewpoint;

[0026] Figure 6 is a schematic axonometric view of a possible embodiment of an apparatus according to the invention during the placement of the wire for making the coil on the ferromagnetic core;

[0027] Figure 7 is a schematic axonometric view of a configuration of minimum mutual distance between the position adjusting means for adjusting the position of the wire C and the compressing means for compressing the wire C;

[0028] Figure 8 is a partially sectional schematic top view of the configuration of Figure 7;

[0029] Figure 9 is a schematic axonometric view of a configuration of maximum mutual distance between the position adjusting means for adjusting the position of the wire C and the compressing means for compressing the wire C;

[0030] Figure 10 is a schematic top view of the configuration of Figure 9;

[0031] Figure 11 plots the charts of the trend of the position, as a function of time, of the ferromagnetic core, of the position adjusting means for adjusting the position of the wire C and of the actuation angle of the compressing means.

[0032] With particular reference to the above figures, the reference numeral 1 generally designates an apparatus designed for making an electric wire coil A on a ferromagnetic core B and thus suitable for executing a method for making an electric wire coil A on a ferromagnetic core B according to the invention.

[0033] The various embodiments of the present invention provide for a method for both making the coil A with a single conductor wire C, arriving from a respective reel D, and making the coil A with a plurality of conductor wires C, each wire C of the plurality of wires C being extracted from a respective reel D, to be wound around the ferromagnetic core B. According to the embodiments that provide for a plurality of wires C, they are mutually superimposed and originate from respective reels D. With reference to Figure 1, the apparatus 1 designed for making the electric wire coil A is equipped with two reels D, each making respective wires C available for the operations of the method for making the electric wire coil A.

[0034] Therefore, the present invention is valid for the winding of at least one wire C, said at least one wire C being chosen from a single wire C and a plurality of wires C. For the sake of non-limiting simplicity, the description of the invention will describe the operations for winding a wire C around the ferromagnetic core B. In any case, as mentioned earlier, embodiments of the present invention provide for the winding of a plurality of wires C, in particular two (see Figure 1), around the ferromagnetic core B, each of the wires C originating from a respective reel D. In other words, the reference to the wire C in the description is to be understood as the at least one wire C. Likewise, the reference to the reel D is to be understood as the at least one reel D relative to the respective at least one wire C.

[0035] The method according to the invention provides for a first step of arranging a ferromagnetic core B on a support 3 which is rotatable with respect to a rotation axis Y, which is followed by a second step of arranging and coupling a terminal portion E of a conductor wire C with respect to the ferromagnetic core B.

[0036] In a preferred embodiment, the rotation axis Y is fixed, allowing to optimize the method by reducing the complexity due to the various elements interacting between the ferromagnetic core B and the wire C during the making of the coil A.

[0037] For example (and without thereby limiting in any way the protective scope defined by the present document), in order to lock the terminal portion E of the wire C it is optionally possible to provide locking clamps 2 of a rotatable support 3 on which the core B is arranged (merely by way of nonlimiting example, the accompanying figures show an embodiment comprising said clamps 2, although they may also be absent, achieving the locking of the terminal E of the wire C in a different way, even in accordance with what is already provided in the background art).

[0038] Performing said operations requires the extraction of a conductor wire C that originates from a respective reel D: in particular, the wire C is wound on the reel D and the step of extracting it must provide for a corresponding unwinding of the wire C from the reel D to make it available for the operations provided below.

[0039] Moreover, the method according to the invention comprises a third step of dispensing, from the respective reel D, the wire C, preferably in a direction which is perpendicular to the direction of the axis Y (although the use of a different direction as a function of the specific requirements of application is not excluded), in substantial alignment with respective portions of the ferromagnetic core B: by virtue of said dispensing of the wire C in substantial alignment with the portion of the core B on which it is to be arranged (forming a turn of the coil A), it is possible to ensure the best arrangement of the turns and, consequently, good compaction of the coil A being provided. Should the dispensing, from the respective reel D, of the wire C, occur at right angles to the direction of the axis Y, an alignment is ensured which facilitates optimum adhesion of the wire C to the surface of the ferromagnetic core B on which it is being wound.

[0040] Simultaneously and in coordination with the dispensing of the wire C, a fourth step of rotation about the axis Y of the ferromagnetic core B arranged on the rotatable support 3 is also carried out, with consequent winding of the wire C on the surface of the ferromagnetic core B, creating turns of wire C around the ferromagnetic core B, in particular around its lateral surface.

[0041] In practice, the core B, by rotating, causes the winding, on its lateral outer surface, of the wire C, which is distributed as a series of turns that form the coil A.

[0042] According to the invention, the method comprises a step of adjusting the position of the wire C around the surface of the ferromagnetic core B.

[0043] The step of adjusting the position of the wire C on the surface (for example, but not exclusively, the lateral surface) of the ferromagnetic core B may be performed by virtue of position adjusting means 4 and compressing means 5.

[0044] The position adjusting means 4 allow to control and manage the position of the wire C, and allow to arrange the wire C, by abutment against at least one part of its surface, so that it is properly juxtaposed against the faces of the ferromagnetic core B (according to the example above, the faces of its lateral surface) and the turns already provided on the core itself (so that each new turn that is arranged is contiguous to the one previously deposited). This allows to adjust the alignment of the wire C on a respective portion of the surface of the ferromagnetic core B.

[0045] Moreover, the step of adjusting the position of the wire C is completed by virtue of respective means 5 for compressing the turns already made and arranged (constituted by the wire C), even indirectly (as might occur if insulating sheets are interposed or if the turns are arranged on a previously made layer of turns), on the surface of the ferromagnetic core B.

[0046] The compressing means 5 are configured to push portions of turns of the wire C against the respective portion of the surface of the ferromagnetic core B according to a respective rule of motion.

[0047] Compression of the wire C on the core B is a key operation, since it allows to avoid elastic deformations and / or bending of the wire C already wound on the core B: in fact, the wire C is constituted by a slender element made of preferably metallic material (generally copper or aluminum, although the use of other materials is not ruled out) which, once subjected to the bending processes necessary to juxtapose it against the core B, can undergo a springback which is opposite to the bending it has undergone and would make the coil A loose and uneven; performing compression of the wire C wound in turns around the core B ensures that the correct tension of the coil A is maintained and thus that it complies with design standards.

[0048] The position adjusting means 4 and the compressing means 5 are jointly mounted on a common slidable frame 7, in which the mutual distance between the position adjusting means 4 and the compressing means 5 can vary to keep both the position adjusting means 4 and the compressing means 5 continuously in contact with the at least one wire C in different portions thereof, during winding around the ferromagnetic core B, thus keeping the position adjusting means 4 and the compressing means 5 at a respective predefined distance with respect to the ferromagnetic core B to draw the at least one wire C.

[0049] With particular reference to a constructive solution of unquestionable practical interest, the predefined distance of the position adjusting means 4 and of the compressing means 5 with respect to the ferromagnetic core B is substantially equal to the thickness of the at least one wire C wound around the ferromagnetic core B.

[0050] It is specified that in the present description the term "shape" (for example, the shape of the core B on which the wire C is wound, or the shape of any other component) is understood to mean the set of geometric parameters that define it, thus the shape proper but also the dimensions (which may cause a greater or smaller width / size of the component) and the proportions among them.

[0051] This step of adjusting the position of the wire C on specific surfaces of the core B is carried out so that the position and the mutual distance between the position adjusting means 4 and the compressing means 5 is defined point by point according to the rule of rotary motion of the ferromagnetic core B, thereby causing an adaptation of the wire C to the shape of the surface of the ferromagnetic core B and maintaining said position adjusting means 4 and said compressing means 5 at a predefined distance from the surfaces of said core B that face them, in order to avoid voids between contiguous turns of the wire C along the direction of the rotation axis Y and between the wire C and the surface of the core B on which it is wound.

[0052] With particular reference to a possible embodiment of the method according to the invention, illustrated by way of nonlimiting example, the rule of motion of the rotation of the core B determines the rule of motion of the position adjusting means 4 and of the compressing means 5, with a consequent variation of their mutual distance for adaptation to the shape of the ferromagnetic core B, ensuring minimization of the voids between contiguous turns of the wire C and between the wire C and the surface of the core B on which it is wound.

[0053] In the accompanying Figure 11 it is possible to see that as a function of the trend of the angular position (plotted in chart I) assumed at a predefined instant by the ferromagnetic core B, the position of the means 4 for adjusting the position of the wire C (plotted in chart II) and the position of the means 5 for compressing the wire C (whose trend of the angle of inclination through which they are actuated is shown in chart III) change.

[0054] The position adjusting means 4 are movable away from and toward the surface of the core B on which the turns of the wire C are wound and have an axial constriction protrusion configured to affect the wire C so as to avoid deformations due to torsional stresses during the forming of the turns.

[0055] The compressing means 5 comprise at least one presser 6 which is mounted so that it can rotate on a first end 21 of a pivoting arm 22 which is pivoted about a respective pivoting axis 23 with respect to the slidable frame 7 ; the presser 6 is therefore movable away and toward the surface of the core B on which the turns are wound.

[0056] The pivoting arm 22 is pivoted on the position adjusting means 4.

[0057] In the step of rotation of the ferromagnetic core B (in which position adjustment may also be performed), each portion (i.e., each point, each portion, each section) of the at least one wire C is abutted preemptively (primarily) by the position adjusting means 4 and subsequently (secondarily) by the compressing means 5.

[0058] As anticipated earlier, in some embodiments these operations are carried out in a structure in which the rotation axis Y is fixed.

[0059] The trend of the position of the position adjusting means 4 and of the compressing means 5 can be understood better by observing the two boundary configurations that occur at specific positions assumed by the ferromagnetic core B during its rotation: Figures 7 and 8 show the configuration in which the position adjusting means 4 and the compressing means 5 are at the minimum mutual distance; Figures 9 and 10 show the configuration in which the position adjusting means 4 and the compressing means 5 are at the maximum mutual distance. As a function of the rotation of the core B on the rotatable support 3, the position adjusting means 4 and the compressing means 5 may assume any configuration (to abut against the wire C and keep it in the ideal arrangement on the surface of the core B) which is intermediate between the minimum mutual distance configuration of Figures 7 and 8 and the maximum mutual distance configuration of Figures 9 and 10. The goal to be achieved by using the position adjusting means 4 and the compressing means 5 is to ensure that the wire C adheres to the surface of the core B as best as possible regardless of its shape (and thus whatever its shape, dimensions and relative proportions).

[0060] With particular reference to a possible constructive solution, the rule of motion of the position adjusting means 4 and the rule of motion of the compressing means 5 may be defined by feedback as a function of the rule of motion of rotation of the ferromagnetic core B (on the rotatable support 3), causing a consequent variation of the mutual distance between the position adjusting means 4 and the compressing means 5, for adaptation of the wire C to the shape of the surface of the ferromagnetic core B and to keep the position adjusting means 4 and the compressing means 5 at a predefined distance from the surfaces of the core B itself that face them.

[0061] In practice, that is, all the steps of the method are controlled by the rule of motion of rotation of the ferromagnetic core B on its respective rotatable support 3: the rotation of the ferromagnetic core B is performed taking into account its shape and the breadth of the angles formed between the contiguous faces thereof, in order to facilitate the juxtaposition of the wire C against the faces of the core B (for example, by slowing down at the arrangement of the wire C on edges of the core B that delimit an acute angle and accelerating upon the arrangement of the wire C on flat faces of the core B).

[0062] According to the invention, the position adjusting means 4 define the position of the wire C on the ferromagnetic core B in a radial direction (more precisely, in a direction at right angles to the lateral faces of the core B, in order to ensure the best juxtaposition of the wire C against said faces and / or turns of an already present layer of the coil A) and in a direction which is parallel to the rotation axis Y, with respect to the core B, so as to affect the surface of the core B and thus avoid unintended deformations due to torsional stresses. As mentioned earlier, the compressing means 5 may conveniently comprise at least one presser 6 which is movable with respect to a frame 7 assigned only to support the position adjusting means 4 for adjusting the position of the wire C: the at least one presser 6 is movable relative to the frame 7 by virtue of the action of a respective actuator 8.

[0063] Merely by way of nonlimiting example, it is specified that the at least one presser 6 might be constituted by at least one idler roller (although it is not ruled out that it might be motorized), by an axially symmetrical rotatable element, by a skid, or by a generic component provided with a surface suitable to abut against the turns of the wire C that are already present on the core B.

[0064] In this constructive solution, the at least one presser 6 can be moved relative to the frame 7, by means of the actuator 8, in a manner that is completely independent of the frame 7 itself, or it can also be coupled to the frame 7 so that the actuator 8 determines a relative motion between the frame 7 and the at least one presser 6.

[0065] It should be specified that the third step of dispensing the at least one wire C in partial alignment with respective portions of the ferromagnetic core B (its surface, preferably the lateral one) is accomplished by means of a dispensing head 9 which is integral with the frame 7. Said dispensing head 9 may be movable on a plane which is perpendicular to the rotation axis Y to align with respect to the core B.

[0066] Therefore, in an embodiment shown by way of nonlimiting example, it is specified that the position adjusting step, performed by virtue of respective position adjusting means 4 and compressing means 5, of the wire C on the ferromagnetic core B may comprise operations for aligning the dispensing head 9 that have to be performed during the execution of the third dispensing step of the wire C, so as to ensure its substantial alignment with respect to respective portions of the ferromagnetic core B.

[0067] The ferromagnetic core B will be generally prismatic, and therefore, in the course of its rotation on the rotatable support 3 (by virtue of the action thereof), considering that the rotation axis Y is preferably fixed, the wire C will be arranged on portions of the core B that are at different distances from the axis Y: the continuous variation of said distances from the axis Y is managed by means of a transverse movement of the dispensing head 9, aimed at maintaining a predefined alignment of the wire C that exits from the head 9 with the portion of the core B on which it is to be juxtaposed and arranged.

[0068] Moreover, as the turns of the wire C are progressively arranged on the core B, the height at which the wire C that arrives from the head 9 is to be arranged also change (since it have to be juxtaposed against a respective portion of the core B, surmounting the last turn already made, i.e., arranging itself above it). For this reason, the dispensing head 9 can also translate parallel to the axis Y, so as to change the height (with respect to the base of the core B) at which to align the wire C to be wound to the core B.

[0069] In addition to the hypothesis of moving the dispensing head 9, the possibility is not ruled out that, alternatively or additionally, the rotatable support 3 on which the core B is fixed also could be subjected to movement: by means of a movement of rotatable support 3, it would be possible to align specific portions of the core B with the dispensing head 9 for dispensing the wire C, thus ensuring in any case that a compact and regular coil A is obtained.

[0070] With particular reference to a particularly efficient embodiment of the present invention, the position adjusting means 4 for adjusting the position of the wire C on the core B and the dispensing head 9 for dispensing the wire C may be coordinated with each other to obtain a compact and regular coil A. By way of nonlimiting example, the position adjusting means 4 for adjusting the position of the wire C on the core B and the dispensing head 9 for dispensing the wire C may be moved with the same rule of motion (defined as a function, optionally also with feedback, of the rule of motion of rotation of the core B on rotatable support 3). It is not ruled out that they may be integral, in order to facilitate their synchronous movement (although this is in any case easily achieved even if they are not integral, by using control techniques of the known type).

[0071] Moreover, the method according to the invention may advantageously comprise a step of transverse displacement of the wire C, at the third dispensing step and at the rotation step coordinated therewith, in which the wire C is moved transversely with respect to the dispensing direction and the rotation axis Y, so as to arrange it facing and close to the surface of the ferromagnetic core B, to wind turns of the wire C which are contiguous to each other, and not superimpose, along the direction of the rotation axis Y, on a single layer of the ferromagnetic core B.

[0072] The present invention also relates to an apparatus 1 for making an electric wire coil A on the surface (preferably the lateral surface) of a ferromagnetic core B; the apparatus 1 comprises a supporting device 10 for at least one reel D for storage of a respective wire C, a dispensing head 9 for dispensing the wire C (which in a constructive solution of unquestionable interest in application and practice could have a polygonal cross-section, for example a rectangular one) that originates from the at least one reel D, a rotatable support 3 for the temporary accommodation of the ferromagnetic core B and its rotation about an axis Y.

[0073] In said apparatus 1, both the position adjusting means 4 and the compressing means 5 are jointly mounted on a common slidable frame 7.

[0074] The apparatus 1 moreover comprises an actuator 8 configured to adjust the mutual distance between the position adjusting means 4 and the compressing means 5 to keep both the position adjusting means 4 and the compressing means 5 continuously in contact with the at least one wire C, in different parts thereof, during winding around the ferromagnetic core B, thus keeping the position adjusting means 4 and the compressing means 5 at a respective predefined distance with respect to the ferromagnetic core B. It is reiterated that the reasoning related to the at least one wire C and the at least one respective reel D is still valid. With reference to Figure 1, the apparatus 1 is shown with two reels D from which to extract respective wires C according to an embodiment of unquestionable interest according to the present invention. As reported above, the various embodiments of the present invention provide either for the configuration with a single reel D from which to extract a respective wire C, or the configuration with a plurality of reels D, for example two (see Figure 1), from which to extract a plurality of wires C to be arranged facing each other for the necessary operations for making the coil A. For the sake of nonlimiting simplicity, when the terms "the wire C" and "the reel D" are mentioned, they are to be understood as the at least one wire C and the at least one reel D, respectively.

[0075] According to the invention, the apparatus 1 advantageously comprises a movable slide 11 configured to support the dispensing head 9 and align the wire C that exits from the dispensing head 9 with the region of the surface of the core B on which it is to be instantaneously arranged.

[0076] The apparatus 1 according to the invention may moreover conveniently comprise a second frame 12, functionally associated with the slide 11, configured only to support the position adjusting means 4, i.e., the means 4 are assigned to adjust the position of the wire C on the core B, i.e., they are configured to abut against at least one part of said wire C and to adjust the alignment of said wire C on a respective portion of the surface of said ferromagnetic core B.

[0077] The apparatus 1 according to the invention also advantageously comprises the compressing means 5 for compressing the wire C on the core B configured to push (being integral with a respective frame 7 and / or 12), with at least one respective portion, portions of turns of the wire C against the respective surface portion of the ferromagnetic core B, so as to avoid deformations of the wire C due to elastic phenomena. In the case of a wire C having a polygonal cross-section, the term "portion of the surface" is understood to mean a face, i.e., a flat region of its lateral surface bounded between two consecutive edges; in the case of a wire C having a crosssection that is circular or generically bounded by a closed line, the term "portion of the surface" is understood to mean a region of indefinite width of its lateral surface.

[0078] More precisely, the position adjusting means 4 and the compressing means 5, operating synergistically, avoid the presence of voids between contiguous turns of the wire C along the direction of the rotation axis Y and between the wire C and the surface of the core B on which it is wound.

[0079] In fact, the wire C is preferably constituted by metallic materials (by way of nonlimiting example, copper and / or aluminum) and thus is subject to elastic reactions to the deformations it undergoes in the course of winding around the core B; these elastic reactions may cause shape deviations, with respect to the ideal arrangement of the turns of the coil A, which, in addition to having negative repercussions on the operation of the coil A (when it will be installed in the electrical machine for which it was designed), entail a lower stability of the coil A itself (some turns will be loose on the core B) and thus the risk that if the wound core B is installed on a moving machine, inertial phenomena may be triggered which would lead in a short time to damage of the wire C.

[0080] It should be pointed out that these phenomena of elastic reaction of the wire C are particularly evident if wire C has a polygonal cross-section, and especially if the wire C has a rectangular cross-section and is wound on the core B by juxtaposing one of its narrower faces against the lateral surface of the core B.

[0081] This last manner of arrangement of the wire C in the making of the coil A is the one that has the most problems in terms of deformations of the wound wire C due to elastic reactions (this is precisely due to the particular shape of the wire C), but it is also the winding mode that ensures that the maximum current density is available during the operation of the electrical machine in which the core B provided with such coil A will be installed.

[0082] According to the constructive solution shown by way of nonlimiting example in the accompanying figures, the frame 7 and the frame 12 may coincide and may be constituted by a single supporting component for both the position adjusting means 4 and the compressing means 5.

[0083] The apparatus 1 according to the invention also advantageously comprises at least one actuator 8 configured to adjust the position of at least one component chosen from the position adjusting means 4 and the compressing means 5.

[0084] Moreover, said actuator 8 ensures the adjustment of the distance of the compressing means 5 from the position adjusting means 4, depending on the rule of rotational motion of the core B on the rotatable support 3 (i.e., performing an associated control, optionally also in feedback, controlled by the rule of rotational motion of the rotatable support 3).

[0085] With particular reference to a constructive solution of unquestionable interest in application and practice, the apparatus 1 may validly comprise a fixed supporting structure 13.

[0086] Between the movable slide 11 and the fixed supporting structure 13 of the apparatus 1 it is possible to advantageously interpose a respective handling member 14 configured for the translation of the slide 11 while maintaining the substantial alignment of the wire C that exits from the respective dispensing head 9 with the region of the surface of the ferromagnetic core B on which it is to be arranged instantaneously.

[0087] In practice, by virtue of the slide 11 which can move by virtue of the action of the handling member 14, it is possible to move the dispensing head 9 for dispensing the wire C, keeping it substantially aligned with the surface of the core B on which the wire C is to be arranged for making of a specific turn of the coil A.

[0088] If one considers that the ferromagnetic core B may be prismatic (having a substantially polygonal cross-section), it is evident that, upon its rotation with respect to the axis Y of the rotatable support 3, the distance between its surface on which to arrange the wire C and the axis Y itself is variable over time (depending on the length and number of sides of the polygon that defines the cross-section of the core B). For this reason, the movements of the dispensing head 9 (obtained by virtue of the movement of the slide 11 by the action of the handling member 14) allow to provide, instantaneously, the correct alignment of the wire C with the portion of the lateral surface of the core B on which it is to be arranged.

[0089] Obviously, as turns are arranged on the core B, the height (with respect to the height of the core B) at which the wire C is to be arranged (which will generally overlap or underlie the turn previously made in the direction of the axis Y) will vary. For this reason, it is possible to provide that the handling member 14 can also vary the height in the direction of the axis Y of the slide 11 , so as to also ensure the alignment of the dispensing head 9 with the specific portion of the core B on which the wire C is to be arranged.

[0090] Preferably, it is possible to perform a height adjustment, along the axis Y, of the position of the ferromagnetic core B by virtue of handling apparatuses 15, 16 configured to vary the height at which the core B is held by changing the vertical elevation of the rotatable support 3.

[0091] As mentioned earlier, the rotation axis Y is preferably fixed.

[0092] With particular reference to an embodiment of unquestionable interest in application, the frame 7, 12 is preferably integral with the slide 11. In particular, the frame 7, 12 might advantageously comprise a post 17, which protrudes with respect to the slide 11, at least partially laterally adjacent to the ferromagnetic core B when arranged on the rotatable support 3.

[0093] The dispensing head 9 can be fully associated with and supported by the frame 7.

[0094] The position adjusting means 4 (therefore assigned to position control and management) for adjusting the position of the wire C on the core B may advantageously comprise an appendix 18 which protrudes toward the core B and is provided with a contoured terminal front, configured and sized for abutment against the wire C (for example, against one of its surfaces) during the deposition thereof on the ferromagnetic core B, i.e., during its winding: this condition may contribute to the creation of turns around the ferromagnetic core B. In the assumption, related to a constructive solution illustrated by way of non-limiting example, in which the dispensing head 9 is integral with the position adjusting means 4, the at least one appendix 18 is coupled to the post 17, which protrudes with respect to the slide 11, of the frame 7, 12 (this does not, however, exclude any alternative arrangement of the at least one appendix 18).

[0095] Said appendix 18 is the main component of the position adjusting means 4 for adjusting the position of the wire C on the core B.

[0096] It is specified that the appendix 18 may advantageously comprise a terminal front provided with a substantially flat surface 19 configured to abut against the part of the surface on the wire C (for example, on part of the corresponding surface that is opposite the part of the surface juxtaposed against the core B) and a laminar protrusion 20 arranged transversely to and overlying the substantially flat surface 19; said laminar protrusion 20 is conveniently configured to abut against a further part of the upper surface of the wire C, so as to compact said at least one wire C on the adjacent turns already wound on the core B, i.e. arranged upstream and / or downstream with respect to the instantaneously abutted turn.

[0097] It is not ruled out to adopt an appendix 18 comprising a lower laminar protrusion 20 configured to abut against the part of the lower surface of the wire C, compacting it onto the overlying turns.

[0098] Likewise, it is specified that the appendix 18 might comprise two laminar protrusions 20, a lower one and an upper one with respect to the substantially flat surface 19, designed to guide the wire C during its arrangement on the core B (in this case, the space between the two laminar protrusions 20 will be not less than the width of the wire C, so that the latter can be interposed between them).

[0099] The compressing means 5 may validly comprise at least one presser 6, coupled to a first end 21 of an arm 22 which pivots with respect to a respective pivoting axis 23 with respect to the position adjusting means 4.

[0100] In this case, the actuator 8 is associated with a second end 24 of the pivoting arm 22.

[0101] In order to properly achieve the intended aim and objects, the actuator 8 may be chosen from a pneumatic cylinder (constructive solution shown by way of nonlimiting example in the accompanying figures), a hydraulic cylinder, a screw / nut assembly, a pusher crank, a linear motor, a pinion / rack assembly, and any combination thereof.

[0102] In other words, changing the position of the stem 25 of the actuator 8 causes oscillations of the arm 22 that change the position of the at least one presser 6, relative to the appendix 18 (thus changing the mutual distance between the compressing means 5 and the adjusting position means 4): these changes in the position of the at least one presser 6 ensure that, while the appendix 18 abuts against the wire C by juxtaposing it against a specific portion of the ferromagnetic core B, the at least one presser 6 compress specific turns of the wire C already provided at a distinct portion of the core B. The oscillation of the arm 22 allows the at least one presser 6 to maintain the correct compression of the turns by following the variation of the shape of the core B as a function of its rotation about the axis Y. In fact, the actuator 8 imposes oscillations of the arm 22 which are dependent on the angular position of the core B on the rotatable support 3 (also taking into account the shape and size of the core B itself).

[0103] The apparatus 1 according to the invention may moreover usefully comprise at least one straightening device 26, arranged upstream of the dispensing head 9 and configured to straighten the wire C itself: said straightening device 26 is favorably provided with elements of the type of calendering rolls, rectifiers with rolling components, conveyor tracks and combinations thereof to straighten the wire C, which, originating from the reel D on which it was wound, would tend to bend elastically (due to elastic "memory" phenomena that would persist even following its unwinding from the reel D). In particular, the straightening device 26 can be interposed between the reel D for storing the wire C and the dispensing head 9 for dispensing the wire C. It is specified that the number of straightening devices 26 comprised in the apparatus 1 depends on the maximum number of reels D that can be accommodated in the apparatus 1 and are useful for dispensing the respective wires C. Each straightening device 26 is therefore arranged between a respective reel D and the dispensing head 9.

[0104] Finally, it is specified that the apparatus 1 according to the invention may favorably comprise at least one processing unit 27 (a controller) which controls handling components comprising at least the actuator 8 and a drive motor of the rotatable support 3 (it is considered that it might comprise a single motor assigned to defining the rule of rotary motion of the core B or also an additional motor assigned to changing the elevation of the core B along the axis Y during the execution of the coil A). It is not ruled out that the handling member 14 also might be controlled by the processing unit 27.

[0105] Said processing unit 27 defines the rule of motion of said components according to the shape, size and rule of rotary motion of the core B on the rotatable support 3.

[0106] Generally, the rotary motion of the core B on the rotatable support 3 will be of a type that is variable according to a predefined rule of motion that must take into account the shape and dimensions of the core B itself.

[0107] It is not ruled out that the position adjusting means 4 for adjusting the position of the wire C may be completely independent of the dispensing head 9: in this case, they will be associated with a respective handling device that defines their rule of motion (controlled by the processing unit 27 mentioned above, according to the principles of generation of the respective rule of motion that have been described), ensuring that the appendix 18 is always in the position suitable to arrange the wire C on the core B, gradually forming turns of the coil A.

[0108] If the compressing means 5 are independent of all the other components, the actuator 8 is controlled by the processing unit 27 to ensure that it can apply the correct pressure to the turn already provided on the core B, acting on successive predetermined portions of the lateral surface of the core B, throughout the entire handling of the core B required to make the entire coil A.

[0109] It should be noted that the presence of the laminar protrusion 20 on the appendix 18 also ensures that, at the edges of the core B, the wire C cannot be subjected to torsional deformations due to the different state of tension to which its parts are subjected: in fact, the region of the wire C closest to the core B, at the edges thereof, is subject to compression, while the outer region is subject to traction, and this could cause even the onset of deformations of a torsional nature that would compromise the quality of the coil A (and are avoided by the particular shape of the appendix 18 provided with the laminar protrusion 20).

[0110] As specified above, the coil A may be constituted by at least one wire C (i.e., in particular, two or more wires C arriving from different reels D may also be superimposed). In fact, as noted earlier, the term "wire C" is to be understood as at least one wire C.

[0111] The accompanying figures show, by way of nonlimiting example, a constructive solution in which there are two reels D assigned to supplying respective wires C: the coil A, in this case, comprises, at each turn, mutually overlapping wires C originating from the two distinct reels D.

[0112] Advantageously, the present invention solves the problems described above, proposing a method for making an electric wire coil A on a ferromagnetic core B that allows to provide optimal turn compaction while avoiding springback phenomena of the wound wire C (regardless of its cross-section and shape), by virtue of the simultaneous presence and respective control (applied by the processing unit 27 with respect to the rule of rotary motion of the core B and its dimensions) of the position adjusting means 4 for adjusting the position of the wire C and the compressing means 5 for compressing the wire C already arranged in turns around the ferromagnetic core B.

[0113] Conveniently, the method according to the invention does not require the presence of operators to control the operation and possibly correct turn positioning errors, by virtue of the fact that the operations for positioning the wire C on the core B and the operations for compressing the wire C already arranged in turns around the core B are controlled and performed as a function of the rule of motion of the rotatable support 3 on which the core B is located and as a function of the shape and dimensions of said core B.

[0114] Advantageously, the method according to the invention is also adapted to be applied with wires C having a rectangular (or generically polygonal) cross-section, regardless of their arrangement on the core B: in fact, even when adopting wires C with a rectangular cross-section, the particular shape of the appendix 18 of the means 4 for adjusting the position of the wire C is such as to keep them in their ideal configuration (avoiding torsional or other deformations).

[0115] Favorably, the apparatus 1 designed for making an electric wire coil A on a ferromagnetic core B is suitable for providing compact windings A juxtaposed against all the surfaces of the ferromagnetic core B, precisely because the means 4 for adjusting the position of the wire C and the means 5 for compressing the already wound turns of the wire C on the core B ensure that the turns are properly arranged in the design configuration, with the right level of compaction (mutual proximity of contiguous turns).

[0116] Positively, the apparatus 1 according to the invention does not require the presence of operators to control its operation and for any correction of turn positioning errors (such errors, in fact, do not occur precisely because of the simultaneous presence of the position adjusting means 4 and of the compressing means 5).

[0117] Usefully, the apparatus 1 according to the invention can also operate with wires C having a rectangular (or generically polygonal) cross-section, regardless of their arrangement on the core B.

[0118] Validly, the method and the apparatus 1 according to the invention are relatively simple to provide in practice and modest in cost: these characteristics make the method and the apparatus 1 according to the invention innovations of assured application.

[0119] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; all the details may furthermore be replaced with other technically equivalent elements.

[0120] In the examples of embodiment shown, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other examples of embodiment.

[0121] In practice, the materials used, as well as the dimensions, may be any according to the requirements and the state of the art.

[0122] The disclosures in Italian Patent Application No. 102023000015534 from which this application claims priority are incorporated herein by reference.

[0123] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

CLAIMS1. Method for making an electric wire coil by winding at least one wire (C) around a ferromagnetic core (B), said method comprising the following steps:- arranging a ferromagnetic core (B) on a support (3) rotatable about a rotation axis (Y),- fixing an end portion (E) of at least one wire (C) on said ferromagnetic core (B),- dispensing, from at least one respective reel (D), said at least one wire (C) toward said ferromagnetic core (B),- rotating said ferromagnetic core (B) about said rotation axis (Y) in order to drag said at least one wire (C) with consequent winding of said at least one wire (C) around said ferromagnetic core (B),- adjusting the position of said at least one wire (C) with respect to said ferromagnetic core (B) by means of respective position adjusting means(4) and compressing means (5), wherein said position adjusting means (4) abut on said at least one wire (C) to align said at least one wire (C) with respect to said ferromagnetic core (B), and wherein said compressing means(5) push the at least one wire (C) against the ferromagnetic core (B), characterized in that both said position adjusting means (4) and said compressing means (5) are jointly mounted on a common slidable frame (7), wherein the reciprocal distance between said position adjusting means (4) and said compressing means (5) can vary between each other for keeping both said position adjusting means (4) and said compressing means (5) continuously in contact with said at least one wire (C) at different portions thereof during winding around said ferromagnetic core (B), thus maintaining said position adjusting means (4) and said compressing means (5) at a respective predefined distance with respect to the ferromagnetic core (B).

2. The method according to claim 1, characterized in that said compressing means (5) comprise at least one presser (6) which is rotatablymounted on a first end (21) of a pivoting arm (22) pivoting about a respective pivoting axis (23) with respect to said slidable frame (7).

3. The method according to claim 2, characterized in that the pivoting arm (22) is pivotally mounted on said position adjusting means (4).

4. The method according to one or more of the preceding claims, characterized in that during the step of rotating said ferromagnetic core (B), each portion of the at least one wire (C) is abutted firstly by the position adjusting means (4) and subsequently by the compressing means (5).

5. The method according to one or more of the preceding claims, characterized in that said step of dispensing the at least one wire (C) is performed by a dispensing head (9) which is integral with said frame (7).

6. The method according to one or more of the preceding claims, characterized in that the predefined distance of said position adjusting means (4) and said compressing means (5) with respect to the ferromagnetic core (B) is substantially equal to the thickness of the at least one wire (C) wound around said ferromagnetic core (B).

7. Apparatus for making an electric wire coil by winding at least one wire (C) around a ferromagnetic core (B), said apparatus (1) comprising- a dispensing head (9) of said at least one wire (C) coming from a respective reel (D),- a rotatable support (3) configured to temporarily hold and to rotate said core (B) about a rotation axis (Y),- position adjusting means (4) configured to abut on said at least one wire (C) to align said at least one wire (C) with respect to said ferromagnetic core (B),- compressing means (5) configured to push the at least one wire (C) against the ferromagnetic core (B), so as to prevent deformations of said at least one wire (C) due to elastic phenomena, characterized in that both said position adjusting means (4) and said compressing means (5) are jointly mounted on a common slidable frame (7),and in that said apparatus further comprises an actuator (8) configured to adjust the mutual distance between said position adjusting means (4) and said compressing means (5) for keeping both said position adjusting means (4) and said compressing means (5) continuously in contact with said at least one wire (C) at different portions thereof during winding around said ferromagnetic core (B), thus maintaining said position adjusting means (4) and said compressing means (5) at a respective predefined distance with respect to the ferromagnetic core (B).

8. The apparatus according to the preceding claim, characterized in that it further comprises a movable slide (11) configured to support said dispensing head (9) and to slide in order to align the at least one wire (C) coming out from said head (9) with respect to the ferromagnetic core (B).

9. The apparatus according to the preceding claim, characterized in that it further comprises a fixed supporting structure (13), and in that between said movable slide (11) and said fixed supporting structure (13) a respective handling member (14) is interposed, said handling member (14) being configured to translate said slide (11), in order to maintain a substantial alignment of the at least one wire (C) coming out of the respective dispensing head (9) with the ferromagnetic core (B).

10. The apparatus according to at least one of the claims 7, 8 and 9, characterized in that said dispensing head (9) is integral with said frame (7).

11. The apparatus according to at least one of the claims 7 - 10, characterized in that said position adjusting means (4) comprise an appendix (18) protruding towards said ferromagnetic core (B) and provided with a terminal front configured and dimensioned to abut against said at least one wire (C) during its winding.

12. The apparatus according to the preceding claim, characterized in that said appendix (18) comprises a terminal front provided with a substantially flat surface (19) and a laminar protrusion (20), said substantially flat surface (19) being configured to abut a portion of thesurface of said at least one wire (C) opposite said ferromagnetic core (B), and said laminar protrusion (20) being arranged transversally with respect to said substantially flat surface (19) and configured to abut a further portion of the surface of said at least one wire (C), so as to compact said at least one wire (C) on coil turns already wound on the core (B).

13. The apparatus according to one or more of the claims 7 to 12, characterized in that said compressing means (5) comprise at least one presser (6) coupled to a first end (21) of an arm (22) pivoting about a respective pivoting axis (23) with respect to said position adjusting means (4).

14. The apparatus according to one or more of the claims 7 to 13, characterized in that it further comprises at least one straightening device (26), arranged upstream of said dispensing head (9) and configured to straighten said at least one wire (C) and provided with straightening elements of the type selected from calendering rolls, rectifiers with rolling components, conveyor tracks and combinations thereof.

15. The apparatus according to one or more of the claims 7 to 14, characterized in that it further comprises one controller (27) to which handling components of said apparatus are associated, said handling components being at least said actuator (8) and a drive motor of said rotatable support (3), said controller (27) defining a rule of motion of said handling components as a function of the shape of said ferromagnetic core (B) and of a rule of motion of the rotation of said core (B) on said rotatable support (3).

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