Assembly for minimizing the resistance of an electrical conductor in a device for tworking the conductor
By temporarily eliminating the gap between the wire and the ferromagnetic core holder in the torsion device, the problem of rebound after twisting is solved, ensuring stable alignment and welding quality of the wire, achieving low cost and ease of use Implemented solutions.
Patent Information
- Application Number
- CN202380044833.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-06-07
- Filing Date
- 2023-06-06
- Publication Date
- 2025-01-03
AI Technical Summary
After the twisting operation, the rebound phenomenon of the electrical conductor causes the gap of the handle of the fork in the ferromagnetic core groove to increase, affecting the welding quality and the correct operation of the motor, and reducing the groove size will complicate the insertion. The rebound cannot be ignored.
Using a torsion device provided with at least one pair of sleeves and a plurality of radial pushers, through the cooperation of the turntable and pushers, the gap between the wire and the ferromagnetic core holder is temporarily eliminated to ensure that the wire is radially pressed before twisting. tight, thereby reducing rebound.
It effectively reduces the rebound phenomenon after twisting, makes wire alignment more stable, and welding more precise and stable, avoids poor quality connections caused by rebound, and achieves a low-cost and easy-to-implement solution.
Smart Images
Figure CN119256479A_ABST
Abstract
Description
[0001] The invention relates to an assembly for minimizing the spring-back of an electrical conductor in a device for twisting such a conductor.
[0002] The torsion device operates on a conducting element (electrical conductor, i.e. electrically conductive element) intended to constitute an induction winding (or wire shaft) of an electric motor, such as a motor, a generator and, in general, any other type of electric motor. In this discussion, the term "wire" will be used to denote any electrical conductor or any corresponding substantially elongated portion of a particular electrical conductor, regardless of its shape and geometrical properties.
[0003] Each conducting element is shaped like a fork, often referred to in industry parlance as a "hairpin", and can be conveniently inserted into a slot in a ferromagnetic core of a stator or rotor of an electric motor. The fork has two straight shanks (substantially parallel) that are interconnected by a crossbar. Overall, each fork is shaped substantially like an upward U, and the profile bridge (constituting the "head" of the fork) is shaped like a sharp corner. Each shank has a free end for inserting the fork into a slot in a core, such as an inductor or armature of an electric motor.
[0004] Insertion is achieved by inserting the free ends of the conducting elements into the longitudinal openings of the slots and sliding them until they protrude from the other end of the ferromagnetic core so that they reach the predetermined external protrusions of the shank. Thus, at one end of the ferromagnetic core, the bridge of the fork remains external, while at the other end of the ferromagnetic core, the free ends remain external.
[0005] After insertion, the free end must be bent (twisting step) to be arranged in a predetermined position in which it is connected via welding (according to the topology of the electrical winding to be provided) to the other free end of the other conducting element (fork). Therefore, the free ends of the separate shanks must be arranged according to a criterion of mutual alignment, which makes the welding operation simple and ensures a high stability of the connection. This alignment is achieved by using a twisting device that deforms the shank of the fork protruding from the ferromagnetic core, aligning the shanks of the separate forks with each other to facilitate their connection (generally speaking welding).
[0006] However, due to the inherent elasticity of the fork material, the handles of the forks, after being deformed by the torsion device, exhibit a springback behavior by tending to recover relative to the torsion force to which they are subjected, which impairs the quality of the alignment obtained and in some cases makes the corresponding ends of the handles of different forks more difficult to connect.
[0007] This problem is particularly harmful because it does not allow to determine that the connection of the ends of the shanks is performed according to predetermined quality standards: it must be noted that a connection of poor quality could jeopardize the correct operation of the electric motor containing the windings due to possible overheating phenomena.
[0008] Specific research projects have shown that the greater the spring-back of the shanks of the forks after the operation of twisting them, the greater the play of the shanks in the slots of the ferromagnetic core that houses them.
[0009] However, it is not possible to reduce the size of the slots in the ferromagnetic core in order to make the springback of the shank negligible, since this would make the insertion of the shank of the fork (hairpin) into these slots too complicated (in some cases, it would be practically impossible to perform this operation using an automatic machine).
[0010] Therefore, by all conventional devices, including attempts to reduce as much as possible the existing play between each groove and the shank of the fork contained therein, it is impossible to make the springback of the shank of the fork negligible after the twisting operation, thus considerably complicating the subsequent welding operation according to the established procedures.
[0011] The object of the present invention is to solve the above-mentioned drawbacks by providing an assembly for minimizing the spring-back of an electrical conductor in a device for twisting such a conductor, which assembly ensures optimal alignment of the conductor ends of the corresponding shanks / conductors of a separating fork made of conductive material, which is arranged in a slot of a ferromagnetic core.
[0012] Within this aim, an object of the invention is to provide an assembly for minimizing the spring-back of an electrical conductor in a device for twisting such a conductor, which assembly ensures stable alignment of the ends of corresponding shanks / conductors of a split fork made of conductive material, which is arranged in a slot of a ferromagnetic core.
[0013] Another object of the invention is to provide an assembly for minimizing the springback of an electrical conductor in a device for twisting such a conductor, which facilitates the operation of joining (welding) the corresponding ends of the shanks / conductors of separate forks made of conductive material.
[0014] Another object of the invention is to provide an assembly for minimizing the springback of an electrical conductor in a device for twisting such a conductor, which makes the joining (welding) of the corresponding ends of the shanks of separate forks made of conductive material more stable and precise.
[0015] Another object of the present invention is to provide an assembly for minimizing the spring-back of an electrical conductor in a device for twisting such a conductor, which assembly is low-cost, easy and practical to implement and safe to use.
[0016] This aim and these objects are achieved by an assembly for minimizing the spring-back of an electrical conductor in a device for twisting such a conductor according to claim 1 .
[0017] This aim and these objects are also achieved by a method for twisting a conductor constituting a winding of an electric motor according to claim 8 .
[0018] Other characteristics and advantages of the invention will become more apparent from the following detailed description of a preferred, but not exclusive, embodiment of an assembly for minimizing the springback of an electrical conductor in a device for twisting such a conductor, which embodiment is illustrated by way of non-limiting example in the accompanying drawings, in which:
[0019] Figure 1 is a schematic perspective view of a possible embodiment of a component for minimizing the spring-back of an electrical conductor in a device for twisting such a conductor in a first step of the method according to the invention, shown from a perspective arranged in the upper region;
[0020] Figure 2 In the first step of the method according to the invention Figure 1 A schematic perspective view of a component arranged in a lower area;
[0021] Figure 3 In the second step of the method according to the invention Figure 1 A schematic perspective view of a component arranged in a lower area;
[0022] Figure 4 In the third step of the method according to the invention Figure 1 A schematic perspective view of a component arranged in a lower area;
[0023] Figure 5 In the fourth step of the method according to the invention Figure 1 A schematic perspective view of a component arranged in a lower area;
[0024] Figure 6 In the fifth step of the method according to the invention Figure 1 A schematic perspective view of a component arranged in a lower area;
[0025] Figure 7 In the sixth step of the method according to the invention Figure 1 A schematic perspective view of the assembly, shown from the perspective of the lower region, wherein the conductors have been completely twisted;
[0026] Figure 8is a schematic perspective view of a pusher provided with shoulders adjacent to wires protruding from corresponding seats of a ferromagnetic core of a stator of an electric motor;
[0027] Fig. 9 yes Figure 8 A schematic side view of the pusher, wire and ferromagnetic core;
[0028] Fig.10 is a schematic perspective view of an enlarged pusher of the type shown in the preceding figures.
[0029] With particular reference to the drawings, reference numeral 1 generally designates an assembly for minimizing the springback of electrical conductors A, and in particular their electrical conductor ends T, of windings B arranged on ferromagnetic cores C in respective seats D of a torsion device 2 .
[0030] The device 2 for twisting the ends T of wires to which the invention relates comprises a fixed body 3 (which is generally rigidly coupled to a fixed frame of the twisting device 2) on which a turntable 4 can rotate, provided with at least one pair of seats designed to temporarily house the ends T of the respective wires A (in order to be able to perform a twisting operation on them). The remaining part of the wire A will be housed in a specific slot of a ferromagnetic core C which will constitute part of the electric motor (motor, generator, transformer, etc.) being built, typically a stator. The turntable 4 comprises at least two sleeves 5, 6, which are circular in cross section (in the technical terminology of the industry, the sleeves 5, 6 are called torsion rings), are concentric with each other and are provided with respective channels 5a, 6a (which define temporary housing seats for the wires A; in practice, each seat can be identified as a space defined by two adjacent channels 5a, 6a), which are substantially parallel to the axis of symmetry IV of the turntable 4 and each of which defines at least one receiving portion, which is in fact configured to partially accommodate at least one wire end T of at least one corresponding wire A protruding from the seat D of the ferromagnetic core C. Each receiving portion will be open on the side directed towards at least one adjacent sleeve 5, 6 (or 6, 5).
[0031] At least two sleeves 5, 6 will be effectively configured to rotate in order to twist the wire end T of the wire A protruding from the seat D of the ferromagnetic core C and partially housed in the channel 5a, 6a.
[0032] In addition to the torsion device 2, the component 1 according to the invention advantageously comprises a plurality of radial pushers 7 which are arranged circumferentially and are configured to be positioned axially between the ferromagnetic core C and the turntable 4, the pushers being configured to be substantially aligned with the space defined between the conductors A, which can be arranged in adjacent channels 5a, 6a.
[0033] Such a pusher 7 is advantageously provided with an end element 9 and a shoulder 8 adjacent to this element 9 .
[0034] According to a preferred embodiment, the pusher 7 is effectively movable in the radial direction between a passive configuration in which the end element 9 is arranged outside the turntable 4, i.e. separated from and facing the wire end T of the wire A protruding from the seat D of the ferromagnetic core C (the passive configuration is located adjacent to the end element 9). Figure 1 , Attachment Figure 2 , Attachment Figure 6 and attached Figure 7 ), shown for illustrative purposes, in the active configuration, the end element 9 of each pusher 7 enters the space defined between the wire ends T of the wire A, which wire ends protrude from adjacent seats D of the ferromagnetic core C and are partially accommodated in adjacent channels 5a, 6a of the turntable 4, so as to be inserted between the wire ends T of the circumferentially adjacent wires A, and the front portion 8a of the respective shoulder 8 abuts against the wire end T of the wire A1 of the wire accommodated in the corresponding channel 5a, 6a (and in the corresponding seat D of the ferromagnetic core C), which channel is arranged outermost and therefore closer to the end element 9 of the respective pusher 7, so as to force such wire end T of the wire A arranged in the corresponding seat D of the ferromagnetic core C against the inner bottom wall E of the seat D, thereby radially compressing them so as to temporarily eliminate their play inside the corresponding seat D before the twisting step is achieved by means of the rotating sleeves 5, 6.
[0035] However, the possibility of adopting an alternative embodiment is not excluded in which, when the pusher 7 is in the passive configuration, the pusher 7 is located radially inside the wire end T of the wire A, the end element 9 being further away from the axis of symmetry IV relative to the shoulder 8 (example not shown in the figures): according to this additional embodiment, the sequence of movements is substantially reversed with respect to the embodiment described in the previous paragraph. In this additional alternative embodiment, the wire A1 will be arranged between the wire housed in the corresponding seat D of the ferromagnetic core C and the channel 5a, 6a. In this case, the wall E against which the wire end T of the wire is pressed will be the outer wall (outside with respect to the axis of symmetry IV).
[0036] This compression of the conductor A in the seat D (groove) of the ferromagnetic core C in fact determines the temporary elimination of the play existing between the seat D and the conductor A, which is thus locked in the seat D (pressed against the internal bottom wall E of the corresponding seat D). The function of the pusher 7 and the corresponding shoulder 8 is to (temporarily) eliminate the play existing inside each seat D and the conductor A housed therein.
[0037] This elimination of play is an important factor, since it makes it possible to carry out a twisting operation on conductor A, which will significantly reduce the springback phenomenon (even to the point of being negligible).
[0038] During the study of the problem of springback of a wire end T subjected to torsion, it is necessary to determine the mechanical properties of the material constituting the wire A, its geometrical properties, the properties of the torsion equipment and the degree of play existing between the wire A and the seat D which houses them.
[0039] The empirical model determined is as follows:
[0040] ΔD = μ·Dtheoretical = (a·ϑ·D / 2+b·g - c·H_pt)·Dtheoretical
[0041] in:
[0042] g is the total radial clearance in the groove;
[0043] ·ϑ is the twist angle;
[0044] H_pt is the final distance between the slot of the torsion device and the stator;
[0045] ΔD is the difference between the external diameter after torsion (measured experimentally) and the theoretical diameter;
[0046] a, b, c are empirical coefficients (must be evaluated in each case for each geometry / material), the condition b>c>a is true (this indicates that the influence of radial clearance in groove g is greater, associated with a multiplication factor for larger sizes).
[0047] Using this empirical model (obtainable experimentally and verifiable and extendable, for example, by applying the Finite Element Method (FEM)), it is found that the parameter with the greatest influence on the final result is the play of the wire A inside the seat D of the ferromagnetic core C: this is because the multiplication factor of g is greater than the other factors.
[0048] It is therefore clear that the use of the pusher 7 provided with the shoulder 8 constitutes an extremely important innovation in the twisting device 2 by ensuring the possibility of temporarily eliminating the play in the groove, i.e. because it minimizes (almost eliminates) the springback of the wire A after twisting.
[0049] With particular reference to an embodiment that is undoubtedly of practical and applicable value, it should be noted that the pusher 7 may certainly have a substantially prismatic elongated shape, the terminal element 9 being tapered.
[0050] The front portion 8a of the shoulder 8 comprises a pair of steps 11 arranged at the side of the terminal element 9, which are adapted to abut against respective wire ends T of the wires A1 protruding from respective seats D.
[0051] With specific reference to the above-mentioned preferred embodiment, the pusher 7 is configured to move toward the symmetry axis IV of the turntable 4 when it changes from a passive configuration to an active configuration, so as to move from a position farther away from the symmetry axis IV of the turntable 4 in the passive configuration to a position closer to the symmetry axis IV of the turntable 4 in the active configuration.
[0052] In this case, the pusher 7 will preferably comprise at its inner end portion (i.e. the portion pointing inwards and suitable for insertion between the respective wires A arranged in adjacent channels 5a, 6a) a tapered end element (coincident with the end element 9) the width of which is smaller than the width of the outside of the pusher.
[0053] It is important to note that the shoulder 8 is substantially arranged in the connection area between the interior of the terminal element 9 and the exterior 10 of the pusher 7 , defining two lateral steps 11 protruding outwards relative to the interior of the terminal element 9 .
[0054] Such lateral steps 11 are suitable for abutting against the outermost conductor A arranged in each corresponding channel 5a, 6a (and the seat D of the ferromagnetic core C), as shown in the attached Figure 8 and Fig. 9 The non-limiting examples are shown in FIG.
[0055] As previously mentioned, the pusher 7 comprises an end element 9 which can be inserted between the wires A present in adjacent channels 5a, 6a (and in the corresponding seats D of the ferromagnetic core C). Each seat D houses a corresponding wire A and a layer of insulating paper P interposed between the inner wall of the seat and the outer surface of the wire A itself: the function of this insulating paper P is to electrically insulate the wire A from the ferromagnetic core C (composed of an electrically conductive material, i.e. an electrical conductor), thereby preventing the flow of current from each wire A to the ferromagnetic core C in the event of damage to the surface insulating layer integral with it.
[0056] The end element 9 of the pusher 7 is conveniently configured to mechanically protect the paper layer during the step of twisting the wire A.
[0057] In fact, while the pusher 7 exerts pressure on the wires A through the shoulder 8, it also ensures through its end element 9 that the paper layer P remains completely attached to the surface of the wires A, thus preventing these wires A from damaging the paper layer P by their movement due to torsion.
[0058] Finally, it should be noted that between the pushers 7 and the fixed body 3, at least one actuator 7a can advantageously be inserted, which is configured to synchronously move radially all the pushers 7. Thanks to the synchronous movement in the radial direction (which ensures the transition from the first passive configuration mentioned to the active configuration mentioned), it is possible to intervene simultaneously on all the wire ends T of the wires A in the seat D of the ferromagnetic core C, so as to avoid the application of uneven external forces on these wires A.
[0059] It should also be noted that at least one receiving portion will be defined by a respective pair of channels 5a, 6a, since each of the pair of channels will be open on a side facing towards the respective adjacent sleeve 6,5.
[0060] According to an alternative embodiment, in a passive configuration, the pusher 7 is located inside the wire end T and will therefore be suitable for forcing the wire end T towards the outer wall E (outside with respect to the axis IV).
[0061] The invention also extends its scope of protection to include a method for twisting the wire ends of a wire A constituting a winding B of an electric motor.
[0062] According to known techniques, this method requires aligning a ferromagnetic core C of the electric motor, which accommodates in respective seats D a plurality of wires A with wire ends T protruding from the front of such core C, with a twisting device 2 for twisting such wire ends T, the twisting device comprising a fixed body 3 on which a turntable 4 is rotatable, the turntable being provided with at least one pair of seats for respective wires A, in particular for protruding wire ends of such wires A. More precisely, the turntable 4 comprises at least two sleeves 5, 6, which are circular in section and are adjacent to each other, concentric, and provided with respective channels 5a, 6a substantially parallel to the axis IV of the turntable 4, each channel 5a, 6a defining at least one receiving portion.
[0063] Also according to the prior art, such a wire end T of the wire A needs to be inserted into the channels 5a, 6a of the sleeves 5, 6. Then, such sleeves 5, 6 can be rotated according to a preset angle, which twists the wire end T of the wire A. Then, the wire end of the wire A can be taken out from the channels 5a, 6a.
[0064] Furthermore, there are a plurality of radial pushers 7 which are arranged circumferentially and positioned axially between the front of the ferromagnetic core C and the turntable 4 so that they are radially aligned in the space defined between the wires A which are arranged circumferentially continuously and which can be arranged in radially continuous channels 5a, 6a.
[0065] In this case, each pusher 7 will be provided with an end element 9 and a shoulder 8 adjacent to the end element 9 .
[0066] According to the invention, prior to the step of twisting the wire ends T by means of the rotation of the sleeves 5, 6, there is a step of moving the radial pusher 7 from a passive configuration, in which the end elements 9 are arranged to be separated from and facing the wire ends T of the wires A protruding from the seats D of the ferromagnetic core C, to an active configuration, in which each end element 9 enters the space defined between the respective wire ends T of the wires A protruding from adjacent seats D of the ferromagnetic core C and partially accommodated in adjacent channels 5a, 6a of the turntable 4, so as to be inserted between the wire ends T of circumferentially adjacent wires A, until the end element abuts against the end element T of the wire A1 (the one closest to the pusher 7) by means of the front part 8a of the respective shoulder 8.
[0067] Prior to the twisting step, there is an additional step of forcing the wires A (more precisely, their wire ends T) arranged in the common seat D of the ferromagnetic core C against the walls E of the respective seat D. This step of forcing the wires A (more precisely, their wire ends T) therefore requires that the wires be compressed radially in order to temporarily eliminate their play inside the respective seat D.
[0068] As previously mentioned, eliminating the play that exists between the wires A and the seats D that house them makes it possible to minimize (or even to neglect) the springback of these wires A after twisting.
[0069] Conveniently, a layer of insulating paper P may be inserted between the inner wall of the seat D of the ferromagnetic core C and the wire A contained therein. Each end element 9 of these pushers 7 is configured so that when the end element 9 is inserted between the wires A in adjacent seats D (and therefore also in adjacent channels 5a, 6a during the twisting operation), it is suitable for keeping the layer of paper P resting on the surface of the wire A adjacent thereto (thus maintaining this mutual arrangement of the layer of paper P and the wire A even during the twisting operation), thereby protecting the layer of paper P from mechanical damage.
[0070] In a preferred embodiment, it should be noted that when the pusher 7 moves from the passive configuration to the active configuration, the pusher moves toward the symmetry axis IV of the turntable 4, that is, in more detail, from a position farther away from the symmetry axis IV of the turntable 4 in the passive configuration to a position closer to the symmetry axis IV of the turntable 4 in the active configuration.
[0071] In a preferred embodiment, the movement of the plurality of movers 7 between the passive configuration and the active configuration will therefore be simultaneous, preventing the generation of uneven stresses on the wires A of the same winding B (arranged on the same ferromagnetic core Q).
[0072] In an alternative embodiment, it should be noted that the pusher 7 moves radially away from the axis of symmetry IV of the turntable 4 when it moves from the passive configuration to the active configuration, i.e., in more detail, from a position closer to the axis of symmetry IV of the turntable 4 in the passive configuration to a position farther away from the axis of symmetry IV of the turntable 4 in the active configuration.
[0073] Also in this alternative embodiment, the movement of the plurality of movers 7 between the passive configuration and the active configuration will therefore be simultaneous, preventing the generation of uneven stresses on the wires A of the same winding B (arranged on the same ferromagnetic core C).
[0074] In the preferred embodiment, it should also be noted that the step of pressing the wire A against the wall E of the corresponding seat D, in which the wire A is radially pressed against the inner bottom wall E of the corresponding seat D, thereby compacting it, continues until the twisting step is completed.
[0075] A similar invention (while providing opposite movement criteria due to the aforementioned structural geometric differences) will also be employed in the aforementioned alternative embodiments.
[0076] It should be noted that the present invention also requires the step of radially spacing the pusher 7 from the twisting device 2 before removing the wire end T of the wire A from the passage 5a, 6a and after the step of twisting by rotating the sleeves 5, 6 is completed.
[0077] Since the pusher 7 presses the wires A against the bottom of the seat D by means of the wall 11 of the shoulder 8 which bears against the wire A1 of the adjacent seat, during the twisting operation the wires A remain immobile in the respective seat D and only their wire ends T are deformed.
[0078] This condition ensures that at the end of the twisting operation, there is no spring-back of the wire end T of the wire A which could impair the correct alignment of the wire (which is necessary for the subsequent welding step).
[0079] At the same time, keeping the end element 9 of the pusher 7 between the wires A also ensures the protection of the insulating paper layer P arranged between the inner wall E of the seat D and the wires A contained therein: in this way, therefore, damage to the paper layer P is also prevented, which damage could cause non-compliance of the winding B (for the specific type of operation for which it is intended).
[0080] Finally, it should be noted that in each of the channels 5 a , 6 a of a respective bushing 5 , 6 defining at least one receptacle, this receptacle is open and faces towards the respective adjacent bushing 6 , 5 .
[0081] Advantageously, according to the invention, a mode of operation has been determined which makes it possible to reduce (or even eliminate) the play existing between the seat D of the ferromagnetic core C and the wire contained therein, before the twisting operation is carried out.
[0082] Therefore, the twisting operation performed with the wire A fixed against the wall E by the shoulder 8 of the pusher 7 will be less prone to the rebound phenomenon after twisting, because this negative phenomenon is closely related to the clearance between the wire A and the seat D accommodating the wire A (as shown in the empirical formula given above).
[0083] Advantageously, the present invention solves the above-mentioned problem by providing an assembly 1 for minimizing the spring-back of these electrical conductors A in a device 2 for twisting these electrical conductors A, which assembly is suitable for ensuring optimal alignment of the ends of the respective shanks of the separating forks (profile conductors A) made of conductive material arranged in the slots of the ferromagnetic core (this optimal alignment is precisely ensured by the fact that, by twisting the ends of the conductors A while they are fixed in the respective seats D by the pushers 7, their spring-back after twisting will be substantially negligible, since the deformations produced during the twisting step will be limited only to the conductor ends T of the conductors A).
[0084] Conveniently, the assembly 1 according to the invention ensures that this alignment will be stable over time due to the precise positioning of the deformation caused by the torsion only in the wire end T of the wire A, which is located downstream of the shoulder 8 and the terminal portion 9 of the pusher 7.
[0085] Advantageously, the assembly 1 according to the invention facilitates the operation of joining (welding) the corresponding ends of the shanks of separate forks (bent wires A) made of conductive material, thanks to their precise and stable positioning at the end of twisting.
[0086] Advantageously, the assembly 1 according to the invention makes the joining (welding) of the respective wire ends of the wires A of the separate forks made of conductive material (called "hairpins" in the industry) more stable and precise, since these wire ends will arrive at the mutual welding device in optimal alignment.
[0087] Positively, the assembly 1 according to the invention for minimizing the springback of an electrical conductor in a device for twisting an electrical conductor is easy and practical to implement and is low-cost: this characteristic makes the assembly 1 according to the invention an innovation that is safe to use.
[0088] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. Furthermore, all the details may be replaced by other technically equivalent elements.
[0089] In the embodiments shown, individual characteristics shown with respect to a specific example may in fact be interchanged with other different characteristics present in other embodiments.
[0090] In practice, the materials used, as well as the dimensions, may be chosen at will according to requirements and the state of the art.
[0091] The disclosures in Italian Patent Application No. 102022000011924 from which this application claims priority are incorporated herein by reference.
[0092] In the event that technical features mentioned in any claim are followed by reference numerals, the sole purpose of including these reference numerals is to increase the intelligibility of the claims and therefore these reference numerals have no limiting effect on the interpretation of each element identified by these reference numerals in an illustrative manner.
Claims
1. An assembly for minimizing the springback of a conductor end (T) of an electric conductor (A) arranged in a seat (D) of a ferromagnetic core (C) when subjected to torsion, the assembly comprising a torsion device (2), the torsion device comprising a fixed body (3), a turntable (4) being mounted on the fixed body so that the turntable (4) can rotate, the turntable (4) comprising at least two sleeves (5, 6), the cross section of the at least two sleeves being circular, and the at least two sleeves being adjacent to each other, concentric and provided with a substantially parallel rotation of the turntable (4). The invention relates to a magnetic core (C) and a magnetic conductor (A) having a plurality of respective channels (5a, 6a) extending along a symmetry axis (IV), each of the channels (5a, 6a) defining at least one receiving portion configured to partially accommodate at least one respective wire end (T) of a wire (A) protruding from a seat (D) of the ferromagnetic core (C), and the at least two sleeves (5, 6) are configured to rotate to perform a twisting on the wire end (T) of the wire (A) protruding from the seat (D) of the ferromagnetic core (C) and partially accommodated in the channels (5a, 6a), characterized in that: The assembly further comprises a plurality of radial pushers (7) which are circumferentially arranged and configured to be positioned axially between the ferromagnetic core (C) and the turntable (4), each of the pushers (7) being provided with an end element (9) and a shoulder (8) adjacent to the end element (9), and the pushers (7) being further capable of moving in a radial direction between a passive configuration and an active configuration, wherein in the passive configuration, the end element (9) is arranged at a distal side of a wire end (T) of the wire (A) protruding from the seat (D) of the ferromagnetic core (C), and in the active configuration, the end element (9) enters a portion of the ferromagnetic core (C) protruding from the seat (D) adjacent to the ferromagnetic core (C). The invention relates to a method for manufacturing a ferromagnetic core (C) having a plurality of conductors (A) and a plurality of conductors (A) disposed in a common seat (D) of the ferromagnetic core (C). The ferromagnetic core (C) comprises ...
2. The assembly according to claim 1, characterized in that The pusher (7) has a substantially prismatic elongated shape, wherein the end element (9) is tapered.
3. The assembly according to claim 1 or 2, characterized in that The front portion (8a) of the shoulder (8) comprises a pair of steps (11) arranged at the side of the terminal element (9), the pair of steps being adapted to abut against respective wire ends (T) of the wires (A1) protruding from the corresponding seats (D).
4. Assembly according to one or more of the preceding claims, characterized in that The pusher (7) is configured to perform a movement toward the symmetry axis (IV) of the turntable (4) when the pusher moves from the passive configuration to the active configuration, thereby moving from a position farther away from the symmetry axis (IV) of the turntable (4) in the passive configuration to a position closer to the symmetry axis (IV) of the turntable (4) in the active configuration.
5. Assembly according to one or more of the preceding claims, characterized in that The terminal element (9) is dimensioned to contact an insulating paper layer (P) inserted between the inner wall of the seat (D) and the outer surface of the conductor (A) to ensure mechanical protection of the paper layer (P) during twisting of the conductor end (T) of the conductor (A) housed in the channel (5a, 6a).
6. Assembly according to one or more of the preceding claims, characterized in that The assembly further comprises at least one actuator (7a) configured for synchronous radial movement of all the pushers (7).
7. Assembly according to one or more of the preceding claims, characterized in that The at least one receiving portion of each channel (5a, 6a) is open on a side pointing toward the corresponding adjacent sleeve (5, 6).
8. A method for twisting a wire (A) constituting a winding (B) of an electric motor, the method comprising the following steps: - aligning a ferromagnetic core (C) of the electric motor, the ferromagnetic core accommodating a plurality of wires (A) in respective seats (D), the wires having wire ends (T) protruding from the front of the ferromagnetic core (C), the twisting device being used to twist the wire ends (T), the twisting device comprising a fixed body (3) on which a turntable (4) is rotatable, the turntable (4) comprising at least two sleeves (5, 6) of circular cross-section and adjacent to each other, concentric and provided with respective channels (5a, 6a) substantially parallel to the axis of symmetry (IV) of the turntable (4), each of the channels (5a, 6a) defining at least one receiving portion, - partially inserting the wire end (T) of the wire (A) into the channel (5a, 6a) of the sleeve (5, 6), - twisting the wire end (T) of the wire (A) by rotating the sleeve (5, 6) according to a preset angle, - removing the wire end (T) of the wire (A) from the channel (5a, 6a), - providing a plurality of radial pushers (7), which are arranged circumferentially and positioned axially between the turntable (4) and the front part of the ferromagnetic core (C), and which are radially aligned with the space defined between the wires (A) arranged continuously in the circumferential direction and which can be accommodated in the radially adjacent channels (5a, 6a), each of the pushers (7) being provided with an end element (9) and a shoulder (8) adjacent to the end element (9), The method comprises, before the step of twisting the wire end (T) by means of the rotation of the sleeve (5, 6): - moving the radial pusher (7) in the radial direction from a passive configuration, in which the end element (9) is separated from and faces the wire end (T) of the wire (A) protruding from the seat (D) of the ferromagnetic core (C), to an active configuration, in which the end element (9) enters the space defined between the wire ends (T) of the wire (A) protruding from adjacent seats (D) of the ferromagnetic core (C) and partially accommodated in adjacent channels (5a, 6a) of the turntable (4) to be inserted between the wire ends (T) of the circumferentially adjacent wires (A) until the pusher abuts against the end element (T) of the wire (A1) adjacent to the corresponding pusher (7) by means of the front part (8a) of the corresponding shoulder (8), and - forcing the wires (A) arranged in the common seats (D) of the ferromagnetic core (C) against the walls (E) of the respective seats (D), thereby compressing the wires radially in order to temporarily eliminate the play of the wires inside the respective seats (D) prior to the step of twisting the wire ends (T) of the wires (A) housed in the channels (5a, 6a) by means of the rotation of the sleeves (5, 6).
9. The method according to the preceding claim, characterized in that An insulating paper layer (P) is inserted between the conductor (A) and the inner wall of the seat (D), and the end element (9) of the pusher (7) is inserted between the conductors (A) arranged in adjacent seats (D) to keep the paper layer (P) resting on the surface of the conductor (A) adjacent to the paper layer during the step of twisting the conductor ends (T) of the conductors (A) accommodated in the channels (5a, 6a) by means of rotation of the sleeves (5, 6), thereby protecting the paper layer (T) from mechanical damage.
10. The method according to claim 8 or 9, characterized in that: When the pusher (7) moves from the passive configuration to the active configuration, the pusher (7) moves toward the symmetry axis (IV) of the turntable (4), thereby moving from a position farther away from the symmetry axis (IV) of the turntable (4) in the passive configuration to a position closer to the symmetry axis (IV) of the turntable (4) in the active configuration.
11. The method according to one or more of claims 8 to 10, characterized in that The step of forcing said wire (A) against the wall (E) of the corresponding seat (D) is prolonged until the twisting step is completed.
12. Method according to one or more of claims 8 to 11, characterized in that The method further comprises the step of radially spacing the pusher (7) from the twisting device (2) before removing the wire end (T) of the wire (A) from the channel (5a, 6a) and after the step of twisting by rotation of the sleeve (5, 6) is completed.
13. Method according to one or more of claims 8 to 12, characterized in that In each of the channels (5a, 6a) of the respective sleeve (5, 6) defining at least one receiving portion, the receiving portion is open and faces the respective adjacent sleeve (5, 6).