Work station for forming induction winding of electric motor

Abstract

A station (1) for forming a grid of induction windings of hairpin-type electrical conductors (C), in which each electrical conductor (C) is forked with two straight pins (D) of different lengths joined by a bridge (F). The station (1) comprises a forming tool (4) configured to temporarily accommodate a plurality of electrical conductors (C) about a first axis of symmetry (2a), thereby forming the grid (3), in which the bridges (F) of each electrical conductor (C) are arranged substantially at the same axial height; the station further comprises a pushing element (7) configured to move along the first axis of symmetry (2a) to push the grid (3) relative to the forming tool (4): the pushing element (7) comprises a pusher (8) provided with an operating surface (8a) designed to abut against a distal front (E) of a pin (D) of an electrical conductor (C) forming the grid (3). The operating surface (8a) of the pusher (8) has a radially inclined annular configuration, the projection of which decreases with increasing distance from the first axis of symmetry (2a) so as to abut against the electrical conductor (C) at different axial heights in the radial direction. The operating surface (8a) is configured to move axially while remaining in abutment with the end front (E) until the operating surface partially lifts the pins (D) of the electrical conductor (C) forming the grid from the forming tool (4), so that the grid (3) can be subsequently removed from the forming tool (4) by means of the removal element (9).

Description

Technical Field

[0001] The present invention relates to a workstation for forming an induction winding of an electric motor. Background Art

[0002] Generally, the induction windings in electric motors (especially the stator windings or rotor windings of motors, alternators, generators, and generators) are provided by wire segments that are easy to form. These wire segments are inserted into the through slots of a ferromagnetic core (such formed wire segments are known in the art as "hairpins"). Then, the end pins of the wire segments are connected together according to a pattern (usually by welding), which can provide a continuous winding distributed according to a specific circuit configuration.

[0003] Generally, in order to facilitate certain operation steps, the process uses wire segments that are longer than the strictly required length.

[0004] During the formation of a grid composed of wire segments on a forming tool, the longer the protruding pins of the wire segments, the more advantageous it is (usually, these segments are inserted one by one into specific seats of the forming tool and temporarily held in these seats until the entire grid is formed), and then they are taken out as a whole and transferred to the ferromagnetic core (where each wire segment is inserted into the correct slot). In fact, wire segments with longer pins enable the easy removal of the grid from the forming tool, which takes advantage of its protrusions to perform this operation (by applying a thrust to the pins protruding from the forming tool in a direction that can remove the entire grid from the forming tool).

[0005] In addition, wire segments with some longer pins enable the separation of some pairs of pins from the rest by taking advantage of the longer length of some of their pins: in fact, it is very simple to insert a separating tool using the gap between the long end and the short end.

[0006] However, this implementation generates a large amount of waste because the longer pins need to be cut before being joined (welded). Cutting is necessary to adapt the length of the pins to the correct occupied space and provide a flat end front at the pins, which is a necessary condition for efficiently welding them together according to traditional techniques. This operation also requires the installation of a suitable cutting workstation in the factory, which significantly increases the cost, both in the procurement phase (these machines are expensive) and during use (this cutting workstation requires energy to operate and needs to be regularly inspected and maintained).

[0007] It is also known that there may be factory facilities where it is not necessary to cut the wire segments, because the pins already have a suitable length to ensure subsequent bending and connection operations according to a predetermined circuit diagram. However, in this case, the end pins of the wire must have a flat end front: this is necessary in order to be able to perform subsequent operations on the pair of pins to be soldered.

[0008] However, the flat end front is very inconvenient during the following operations: first inserting the pin into the seat of the forming tool (during grille formation), and then, after the grille is fully formed, inserting it into the slot of the ferromagnetic core (during the process of introducing the grille into the ferromagnetic core). In fact, having pointed pins facilitates the insertion operation because the corresponding inclined surfaces can be used to guide each end to the corresponding seat and / or slot.

[0009] For this reason, the insertion operation requires the use of very precise machines or the adoption of auxiliary components to ensure that each end front can be accurately aligned with the corresponding seat (and / or corresponding slot). These structural measures mean a high procurement cost for the components required for the normal operation of the factory and extremely high precision requirements for construction / installation. These measures mean a high cost for providing such a factory.

[0010] WO2022136488 of the same applicant discloses a method capable of soldering together the end portions of the pins having a pointed-type end front. Due to the difficulties in the operations of inserting the pins of the wire and necking down (i.e., regrouping or re-grouping) the pins of the wire into multiple pairs (or groups), the method described in WO2022136488 cannot be advantageously applied effectively and economically. Summary of the Invention

[0011] The object of the present invention is to solve the above-mentioned defects by providing a workstation for forming the induction winding of an electric motor, which can easily operate on the grille of the conductor, wherein the pins do not need to be cut before joining the pins together to form a group consisting of at least two pins.

[0012] Within this object, the aim of the present invention is to provide a workstation for forming the induction winding of an electric motor, which does not need to be associated with a workstation for cutting the pins.

[0013] Another object of the present invention is to provide a workstation for forming the induction winding of an electric motor, which does not need to use a high-precision machine to perform the following operations: inserting the pins into the corresponding seats of the forming tool during grille formation; and inserting the pins into the slots of the ferromagnetic core during the process of introducing the grille into the ferromagnetic core.

[0014] Another object of the present invention is to provide a workstation for forming the induction winding of an electric motor, which can ensure, without using auxiliary components, that during the formation of the grid, the front part of each end is accurately aligned with the corresponding seat of the forming tool; and during the introduction of the grid into the ferromagnetic core, the front part of each end is accurately aligned with the slots in the ferromagnetic core.

[0015] Another object of the present invention is to provide an apparatus for forming the induction winding of an electric motor, which enables the teachings of WO2022136488 to be applied in the final step of joining the individual pins of the wire by a welding process.

[0016] Another object of the present invention is to provide a workstation and an apparatus for forming the induction winding of an electric motor, which are inexpensive, easy to implement and safe to use.

[0017] This object and these objects are achieved by the workstation according to claim 1.

[0018] This object and these objects are also achieved by the apparatus according to claim 6.

[0019] This object and these objects are also achieved by the method according to claim 11 and the method according to claim 13. Description of the Drawings

[0020] Other features and advantages of the present invention will become more apparent from the following detailed description of preferred but non-exclusive embodiments of a workstation and an apparatus for forming the induction winding of an electric motor, which are shown by way of non-limiting examples in the accompanying drawings, in which:

[0021] Figure 1 is a block diagram of an apparatus for forming the induction winding of an electric motor according to the present invention;

[0022] Figure 2 is a schematic perspective view of an embodiment of a workstation of an apparatus for forming the induction winding of an electric motor according to the present invention, configured to form a grid of electrical conductors, the workstation being in a configuration fully accommodating the electrical conductors;

[0023] Figure 3 is in Figure 1 the configuration of Figure 1 a partial cross-sectional schematic perspective view of the workstation;

[0024] Figure 4 is a cross-sectional schematic view of the workstation in the configuration of Figure 1 taken along a transverse plane passing through the main symmetry axis; Figure 1 of the workstation;

[0025] Figure 5is in the configuration of the discharge of the electrical conductor part Figure 1 is a schematic perspective view of a workstation, and these electrical conductors remain protruding from the surface of the forming tool that houses them;

[0026] Figure 6 is in Figure 5 the configuration of Figure 1 is a schematic partial cross-sectional perspective view of a workstation;

[0027] Figure 7 is a cross-sectional schematic view of a workstation in the configuration of Figure 5 taken along a transverse plane passing through the main symmetry axis; Figure 1 is a cross-sectional schematic view of a workstation;

[0028] Figure 8 is a cross-sectional view of an embodiment of a grouped workstation taken along a transverse plane passing through the main symmetry axis, and the grouped workstation is provided with at least one element configured to group at least a part of the pins of the electrical conductors protruding from the corresponding ferromagnetic cores;

[0029] Figure 9 is Figure 8 an enlarged view of detail IX shown in;

[0030] Figure 10 is a cross-sectional schematic view of a grouped workstation taken along a transverse cross-section passing through the main symmetry axis; Figure 8 is a cross-sectional schematic view of a grouped workstation;

[0031] Figure 11 is Figure 10 an enlarged view of detail XI shown in;

[0032] Figure 12 is a schematic perspective view of an electrical conductor of a type suitable for being processed by a device according to the present invention;

[0033] Figure 13 is a schematic perspective view of the arrangement of electrical conductors before being joined together by welding;

[0034] Figure 14 is a schematic perspective view of a possible torsional element of a grouping device of a device according to the present invention. Detailed Description of the Invention

[0035] Specifically referring to the drawings, reference numeral 1 generally represents a workstation for forming an induction winding of an electric motor.

[0036] Specifically, the induction winding produced by workstation 1 can be a winding of a stator or a rotor of an electric motor (such as an electric machine, an alternator, a generator, etc.).

[0037] However, the possibility of using station 1 to provide induction windings intended for transformers, electromagnetic brakes, linear induction motors, etc. is not excluded.

[0038] In all these cases, there is a core made of ferromagnetic material A, which is provided with through slots B (substantially parallel to each other), and the electrical conductors C forming the winding can be accommodated in these through slots.

[0039] The electrical conductor C is preferably constituted by wire segments that are usually at least partially coated with a layer of insulating (dielectric) material. The shaped wire segments intended for providing the winding are known in the art as "hairpins" due to their unique shape.

[0040] The conductor C includes two pins D having end fronts E and is in the shape of a fork. These two pins D are connected together by a central portion F, which constitutes a connection bridge (simply referred to as the bridging portion F) between the two pins.

[0041] The pins D must be accommodated in the slots B of the ferromagnetic core A, while the central portion F remains outside the core A (basically facing and close to the head G of the core). A plurality of conductors C (electrically connected to each other) are connected (by coupling the end fronts E in pairs or groups) according to a predetermined pattern to form the induction winding.

[0042] Station 1 is configured to arrange the electrical conductors C according to a predetermined pattern to form a grid 3. Station 1 is provided with a tool 4, which is used to temporarily accommodate the conductor C (with its pins D inserted into the corresponding seats 5, and the bridging portion F facing the upper head 6 of the station 4) and form the grid 3.

[0043] The operation of introducing the conductor C (hairpin) into station 1 to form the grid 3 (commonly referred to as a "basket" in the art) is a method according to the background art (which has been described in the previous patent documents by the same applicant): This introduction can advantageously be carried out by an automated device for introducing the conductor element C. Preferably, the automated device introduces the conductor elements one by one to position them more accurately within the forming tool 4.

[0044] Station 1 includes a forming tool 4, which is configured to temporarily accommodate a plurality of conductors C around a first axis of symmetry 2a to form a grid 3, wherein the bridging portion F of each conductor C is substantially arranged at the same axial height. Station 1 also includes a pushing element 7, which is configured to move along the first axis of symmetry 2a to push the grid 3 relative to the forming tool 4 to move the grid away (i.e., push the grid 3 outward relative to the forming tool 4). The pushing element 7 further includes a pusher 8 provided with an operating surface 8a, which is designed to abut against the end front E of the pin D of the electrical conductor C constituting the grid 3.

[0045] The operating surface 8a of the pusher 8 has an annular configuration that is inclined radially, with its protrusion decreasing as it gradually moves away from the first axis of symmetry 2a: in fact, the operating surface 8a of the pusher 8 has a substantially convex shape (where the maximum protrusion is close to the axis 2a). In fact, the shape of the operating surface 8a is designed to abut against the electrical conductor C at different axial heights in the radial direction.

[0046] The pusher 8 is conveniently configured to be movable from a first configuration to a second configuration parallel to the first axis of symmetry 2a. In the first configuration, the pusher is arranged at a predetermined maximum distance from the second surface 6. In the second configuration, the operating surface 8a of the pusher 8 is closer to the second surface 6 compared to the first configuration (both configurations are within the stroke of the pusher 8, and the range of this stroke is selected according to the expected operating requirements during the design phase), and the pin D of the electrical conductor C partially protrudes from the second surface 6.

[0047] The operating surface 8a is actually configured to move axially while maintaining abutment (and thus impact) against the end front E until it partially lifts the pin D of the electrical conductor C forming the grid 3 from the forming tool 4 (i.e., by means of synchronous lifting, causing all the conductors C forming the grid 3 to be "exposed" or "raised" relative to the top of the forming tool 4), so that subsequently the grid 3 can be removed from the forming tool 4 by means of the removal element 9 (the end of which is provided with clamping protrusions 11 configured to hold the grid 3).

[0048] It should be noted that it is conceivable that the pin D and / or the electrical conductor C will not undergo plastic deformation due to this lifting operation.

[0049] In fact, the length of the axial stroke executed by the pusher when the pusher 8 comes into contact with the end front E is equivalent to the axial movement of the conductor C in the direction parallel to the axis 2a: in fact, the pusher 8 synchronously lifts all the conductors C.

[0050] Therefore, during the lifting process (and after the lifting is completed), the bridging portions F of the conductor elements C remain substantially aligned with each other (or more precisely, they will maintain their respective relative axial heights), and then the grid 3 is removed and subsequently moved to transfer the grid to a work station for inserting it into the through slot B of the ferromagnetic core A.

[0051] With particular reference to an embodiment that undoubtedly has practical and application value, the operating surface 8a of the pusher 8 has at least one configuration (shape structure) selected from the following: frustoconical, hemispherical, spherical, paraboloidal, hyperboloidal, polyhedral, and / or their combinations.

[0052] It should be noted that the substantially frustoconical operating surface of the pusher 8 of the pushing element 7 for removing the grid 3 from the tool 4 faces the seat 5 of the forming tool 4.

[0053] The pusher 8 (and, obviously, the operating surface 8a integrally formed therewith) can conveniently move from a first configuration (as shown by way of non - limiting example in Figure 3 and Figure 4 ) to a second configuration (as shown by way of non - limiting example in Figure 6 and Figure 7 ). In the first configuration, the pusher is arranged at a predetermined distance from the forming tool 4. In the second configuration, the pusher faces and is close to the first surface 15 of the forming tool 4 (in the drawings, the first surface 15 corresponds to the lower head of the tool 4).

[0054] It should be noted that during the transition from the first configuration to the second configuration, contact occurs between the front part E and the operating surface 8a to achieve synchronous lifting. In fact, in the second configuration, this lifting has already occurred, and this lifting is actually caused by the axial movement of the pusher 8.

[0055] Therefore, the forming tool 4 preferably includes a first surface 15 and a second surface 6, which corresponds to the upper head 6 of the tool 4, is arranged opposite to the first surface, and the bridging part F of the conductor C of the grid 3 protrudes relative to the second surface.

[0056] In this second configuration, the substantially frustoconical operating surface of the pusher 8 closely fits with the front end part E of the pin C of the electrical conductor C, thereby determining the partial exposure of the electrical conductor from the seat 5 and the protrusion of the electrical conductor from the second surface (coinciding with the upper head 6) of the forming tool 4.

[0057] In fact, by looking at Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 (provided by way of non - limiting example), the arrangement of the grid 3 can be observed: in particular, in Figure 2 , Figure 3 and Figure 4 , the arrangement of the grid 3 when the pusher 8 (and its acting surface) is in the first configuration mentioned can be seen; while in Figure 5 , Figure 6 and Figure 7 , the arrangement of the grid 3 when the pusher 8 (and its acting surface) is in the second configuration mentioned can be seen.

[0058] The forming tool 4 can advantageously include a body 14, which is symmetric about a first axis of symmetry 2a and is provided with a plurality of seats 5. Each of these seats 5 is configured to accommodate at least one pin D of the electrical conductor C in a direction parallel to the first axis of symmetry 2a.

[0059] It should be noted that the seat portion 5 can advantageously be arranged in a ring shape on the body 14 and can advantageously be distributed with the same geometry as the slots B of the corresponding ferromagnetic core A.

[0060] In this way, the shape and size of the grille 3 formed on the tool 4 are such that the grille can be transferred to the corresponding ferromagnetic core A without any modification thereof.

[0061] In a particularly effective application embodiment, the seat portions 5 can advantageously be arranged circumferentially (i.e., along a circumference preferably centered on the axis 2a) and separated from each other by corresponding radial partitions.

[0062] The pusher 8 is conveniently configured to move from a first configuration to a second configuration parallel to the first symmetry axis 2a. In the first configuration, the pusher is arranged at a predetermined maximum distance from the second surface 6. In the second configuration, the operating surface 8a of the pusher 8 is closer to the second surface 6 compared to the first configuration (both of these configurations are included within the stroke of the pusher 8, and the range of this stroke is selected according to the expected operating requirements during the design phase), and the pin D of the electrical conductor C partially protrudes from the second surface 6.

[0063] It should be noted that the forming tool 4 can advantageously include a restraining element 19, which is symmetric about the first axis 2a, located above and concentric with the pusher 8, and can move integrally with the pusher 8. The size of the restraining element 19 is designed such that the shape of its lower surface matches the shape of the upper surface of the pusher 8, thereby ensuring that one of them stably rests on the other. The restraining element 19 has a generally cylindrical geometry at least in the part in contact with the pusher 8, and its upper part can be tapered, such as frustoconical, curved surface or similar shapes. It should be noted that the diameter of the restraining element 19 is slightly smaller than the distance between the top part of the pusher 8 and its corresponding operating surface 8a and the symmetry axis 2a of the tool, so as to be inserted into the pusher. This restraining element 19 preferably includes at least one first cylindrical side surface 20, which protrudes in the direction of the first symmetry axis 2a with respect to the pusher 8 and is configured to radially restrain the pin D of the conductor element C. The first cylindrical side surface 20 optionally serves as a physical restraint / barrier for the pin D of the conductor element C at a position more inside than the grille without causing plastic deformation of the conductor C, thereby ensuring higher stability both during the insertion of the conductor element C into the forming tool 4 and during the lifting of the grille 3 after its formation.

[0064] The present invention also relates to an apparatus 100 for forming an induction winding arranged in the slots B of a ferromagnetic core A of an electric motor, the apparatus including at least one work station 1 for forming a grille 3 of the induction winding of the aforementioned type.

[0065] The device 100 further includes a pick - up element 9, which is configured to pick up the grid 3 of the electrical conductor C from the forming tool 4 (a clamping protrusion 11 configured to hold the grid 3 is provided at the end of the pick - up element), and then insert the grid into the ferromagnetic core A symmetric about the second symmetry axis 2b, such that each pin D of the conductor C is received in a corresponding slot B of the core A.

[0066] The device 100 further includes a grouping device 10, which is configured to divide (i.e., re - divide) the pins D into a plurality of groups. Each group in these groups includes at least the pins D of the conductor C arranged in the core A, and these pins are arranged at substantially the same radial distance from the second symmetry axis 2b.

[0067] The dimensions of the grouping device 10 are conveniently designed to act on the longitudinal portion H adjacent to the end front E of each pin D in the group.

[0068] It is noted that the grouping device 10 may conveniently include a widening element 12, which is configured and dimensioned such that: first, it can be translated parallel to the second symmetry axis 2b of the conductor C so as to be inserted into the gap 17 between two radially adjacent pins D of different electrical conductors C, thereby bringing the longitudinal portion H of the pins D to a predetermined axial height; second, it can also be translated in the radial direction relative to the second symmetry axis 2b so as to at least partially deform the portion H of the pins D, thereby moving them away from the second symmetry axis 2b.

[0069] The widening element 12 includes at least one partition 16, which is configured and dimensioned to be axially inserted into the gap 17. The at least one partition 16 includes an edge 18, which is configured and dimensioned such that: first, it faces the end front E of the pin D during translation along a direction parallel to the second symmetry axis 2b; and second, it abuts against a part of the end front E of one of the two pins D defining the gap 17.

[0070] It should be noted that the widening element 12 is configured to neck down or re - divide at least one part H of the pins D of different electrical conductors C protruding from the corresponding ferromagnetic core A into a plurality of groups (preferably, the widening element 12 is configured to neck down or re - divide a group composed of at least two parts H into a plurality of groups, as shown by way of non - limiting example in the drawings). The at least one partition 16 included in the widening element is very thin.

[0071] The partition 16 is advantageously configured to be translated along a direction parallel to the longitudinal axis of the pin D of the conductor C: such translation along a direction parallel to the pin axis enables the partition 16 to enter the gap 17 defined by two adjacent pins D of different electrical conductors C up to their predetermined length range.

[0072] In addition, the partition 16 is effectively configured to also be additionally translatable in a direction substantially transverse to the longitudinal axis of the pin D, so that a portion of these pins D is deformed according to a predetermined geometry (in order to achieve the alignment of the front ends E of some of the pins D of different conductors C according to the specifications of the circuit diagram of the induction winding it is intended to provide).

[0073] It should be noted that the top portion 18 of the partition 16 can advantageously be wedge-shaped (i.e., the thickness gradually decreases towards its end edge): this particular shape structure facilitates its entry into any gap 17 defined between two adjacent pins D.

[0074] With particular reference to the characteristics of the conductors that can be processed using the device 1 of the present invention, it should be noted that the front ends E of the pins D of the relevant electrical conductors C must be tapered.

[0075] The tapered surfaces L of the front ends E of two adjacent pins D of different conductors C define corresponding inclined planes that converge along the gap 17 defined between the adjacent pins D.

[0076] To achieve the described conditions, at least two inclined and tapered surfaces L are required, and in the extreme case where the front end E is wedge-shaped, they are arranged to form a ramp to guide the partition 16 towards the gap 17.

[0077] More specifically, it should be noted that the front end E of the pin D of the electrical conductor C can have a shape structure selected from the following: wedge-shaped (in this case, the top edge of the wedge is advantageously parallel to the surface defining the gap 17 between adjacent pins D of different conductors C), pyramidal, frustoconical, conical, truncated conical, partially spherical, partially elliptical, partially paraboloidal, etc.

[0078] The shape structure of the front end E must be tapered to facilitate guiding the partition 16 towards the gap 17: when the partition 16 is pushed onto the pins, this taper allows a slight deformation of a portion H of the pin D until the partition 16 is correctly directed towards the gap 17 into which it is to be inserted.

[0079] The thin partition 16 includes an edge (of the top portion 18) facing the front end E of the pin D. When translating in a direction parallel to the longitudinal axis of the pin D of the conductor C, this edge (of the top portion 18) conveniently abuts against some portions (inclined surfaces L) of the front end E of one of the two pins D that define the gap 17 into which the partition 16 is to be inserted. This will determine the subsequent guiding of the partition 16 towards the gap 17, which is achieved by the surfaces L of those portions of the front end E that substantially constitute inclined planes.

[0080] More specifically, it should be noted that the implementation of the verified functions of the grouping device 10 may clearly also include a torsion element 10a, which includes at least one first sleeve 10b, 10c and at least one second sleeve 10d, 10e. These sleeves 10b, 10c, 10d, 10e preferably have a circular cross-section, are concentric with each other and are mounted to be rotatable about a third axis of symmetry 2c of the torsion element 10a (in fact, the sleeves 10b, 10c, 10d, 10e have at least one degree of rotational freedom about the axis 2c relative to the axis 2c). Each of at least one first sleeve and the second sleeves 10b, 10c, 10d, 10e is provided with a respective channel 10f, 10g, 10h, 10j, which are configured to accommodate the widened longitudinal portions H of the end portions of the constituent pins D of each conductor C to be twisted and are arranged parallel to the third axis of symmetry 2c.

[0081] It should be noted that this arrangement and the rotational movement of at least one first sleeve and at least one second sleeve 10b, 10c, 10d, 10e are carried out about a third axis of symmetry 2c that coincides with the second axis of symmetry 2b.

[0082] The torsion element 10a of the device 100 further includes at least one moving element (not shown in the drawings but which can be provided in a manner known to those skilled in the art and / or those belonging to the background art) for at least one first sleeve and one second sleeve 10b, 10c, 10d, 10e, which at least one moving element is configured to cause at least one first sleeve 10b, 10c and the second sleeves 10d, 10e to rotate relative to each other, so as to twist the longitudinal portion H. The rotation of the sleeves 10b, 10c, 10d, 10e takes place along a stroke from an initial position in which the longitudinal portion H retains the shape it had before being received in the channels (10f, 10g, 10h, 10j) to a final position in which each portion H deformed by twisting the conductor C is offset circumferentially (along an arc of a circle) until a different alignment configuration of the radially adjacent portions H is achieved.

[0083] It should be noted that in the case where the grouping device 10 includes both a widening device and the torsion element 10a, the longitudinal portions H to be inserted into the sleeves 10b, 10c, 10d, 10e of the torsion element 10a already have a widened shape due to the operations carried out in the widening element 12. In this case, the rotation of the sleeves 10b, 10c, 10d, 10e takes place along a stroke starting from an initial position in which the longitudinally widened portion H retains the shape it had when received from the widening element 12.

[0084] The device 100 further includes interconnecting means 13 configured to interconnect the longitudinal portions H belonging to the same winding.

[0085] The interconnecting device 13 preferably further includes a welding unit configured to weld together at least two adjacent end fronts E that are substantially positioned at the same axial height without the need for a prior cutting operation to equalize the axial protrusion or overhang relative to the ferromagnetic core.

[0086] It should also be noted that the device 13 for stably interconnecting the parts H belonging to the same set of pins D (which is not shown in its entirety in the figures since its type is substantially known; for the purposes of a non-limiting example only, the device 13 may correspond to the device described in WO2022136488) includes a laser welding unit for welding together the fronts E (and a part of the adjacent part H).

[0087] The laser welding unit includes a control and management module for a number of devices configured to direct and move a laser beam along the end fronts E of the pins D of the multi-group electrical conductors C according to programmable movement rules. By selecting suitable movement rules, the end fronts E can be melted, initially confined only to the most central region of each front E and subsequently spreading to all the fronts E of the same group, thus welding them together.

[0088] The scope of the present invention also relates to a method of forming a grid 3 of electrical conductors C for an electric motor winding, wherein each conductor C is hairpin-shaped, in the form of a fork, and has two straight pins D of different lengths connected by a bridging portion F. In such a conductor C shaped as a fork-shaped hairpin, each pin D includes a respective end front E.

[0089] The method includes the following steps.

[0090] Step II: An annular grid 3 is formed within the tool 4 (which has a first axis of symmetry 2a) by arranging the electrical conductors C within the tool 4 for temporarily accommodating the conductors C according to a predetermined pattern. In step II of forming the grid 3, the conductors C are arranged within the tool 4, wherein the end fronts E of the pins D are located in a radial plane, the longer pins are farther from the first axis of symmetry 2a, and the bridging portion F of each conductor C is substantially arranged at the same axial height and protrudes above the tool 4.

[0091] Next, step III is carried out: A thrust is applied to the grid 3 relative to the tool 4 by means of a pusher 8 that can move in the direction of the first axis of symmetry 2a. The pusher 8 is provided with an operating surface 8a designed to abut against the end fronts E of the pins D of the electrical conductors C of the grid 3.

[0092] During the pushing step III, the conductor elements C do not undergo plastic deformation because the sole purpose of this pushing is to move the conductors C axially so that they can be further manipulated by the extraction element 9, which, through the exposed grille 3, can completely remove the grille from the tool 4 to move all the conductors C to another workstation for inserting the grille 3 into the ferromagnetic core A.

[0093] According to the invention, the operating surface 8a of the pusher 8 simultaneously abuts against the front ends E of the electrical conductors C at different axial heights in the radial direction.

[0094] The operating surface 8a moves axially while maintaining abutment against the front ends E (i.e., abutting against the corresponding front ends E) until it partially lifts the pins D of the electrical conductors C forming the grille from the forming tool 4 (i.e., by means of synchronous lifting, causing all the conductors C forming the grille 3 to "emerge" or "rise" relative to the top of the forming tool 4). In fact, since no other external forces (except weight, i.e., gravity) act during the pushing step III, the only possible effect is the rise of the grille 3, from which it is predicted that the conductors C will not undergo significant plastic deformation, which could change their geometry related to the first forming step II of the grille 3.

[0095] During this operation, the pins D remain straight so that the grille 3 can subsequently be removed from the forming tool 4.

[0096] It is worth noting that during the forming step II of the grille 3 and the pushing step III of the grille 3 (to move it away from the forming tool 4), the shape of the conductors C remains substantially unchanged, from which it is envisaged and / or determined that no significant plastic deformation occurs.

[0097] It is worth noting that the method according to the invention can advantageously include a preparatory step I of preparing a plurality of electrical conductors C, wherein the longer the length of each pin D, the further its position in the grille 3 relative to the first symmetry axis 2a.

[0098] Therefore, this additional preparatory step I also includes: cutting each conductor C to a suitable length, optionally removing the surface insulation layer from a specific end portion of the pin D of the conductor C, and optionally shaping it into a specific shape, such as the so-called "hairpin" shape (because of its shape similar to a hairpin).

[0099] Each conductor C thus prepared is suitable for providing a specific part of the corresponding induction winding without further cutting any of its end portions.

[0100] The method of forming the winding further includes an extraction step IIIa: extracting the grid 3 from the forming tool 4 so that the grid 3 can then be inserted into the ferromagnetic core A (as already explained in step III, the conductor C also does not undergo significant plastic deformation in step IIIa).

[0101] It is worth noting that after the extraction step IIIa, the method of forming the winding can advantageously include the following steps:

[0102] - Transfer step IV, transferring the grid 3 into the ferromagnetic core A and arranging each pin D of each conductor C inside the corresponding slot B of the core A.

[0103] - Grouping step V, dividing these pins D into multiple groups: each group in these groups at least includes the pins D of the conductors C arranged at the same radial distance from the second symmetry axis 2b in the core A, so as to act on the corresponding longitudinal part H adjacent to the end front E of each pin D in the group.

[0104] - Joining step VI, joining (i.e., deforming by performing a widening operation along the radial direction and / or determining at least partial twisting) the end fronts E of the grouped parts H belonging to the same winding.

[0105] It is worth noting that after the grouping step V, the end fronts E of each conductor in the conductors C belonging to different groups have substantially the same axial height in the final position with respect to the second symmetry axis 2b. Therefore, before the joining step VI, there is no need to perform other steps of cutting the longitudinal part H to make the axial protrusion amounts of the end fronts E of the conductors C inserted into the core A equal.

[0106] It is worth noting that the grouping step V can effectively include a necking step Va, which includes: symmetrically deforming the longitudinal part H group in the radial direction with respect to the second symmetry axis 2b by means of a widening element 12 including at least one partition 16. First, move the widening element 12 in a direction parallel to the second symmetry axis 2b, thereby inserting the corresponding partition 16 axially into the gap 17 defined by two longitudinally adjacent parts H until reaching a predetermined axial height with respect to the second symmetry axis 2b. Subsequently, move the element 12 in the radial direction with respect to the second symmetry axis 2b, thereby deforming the pins D of the part H in the radial direction according to a predetermined geometry.

[0107] It should also be noted that the grouping step V can effectively include a twisting step Vb, in which the longitudinal portions H of each of at least two groups of pins D arranged at the same radial distance are first inserted into at least one corresponding rotating annular sleeve 10b, 10c, 10d, 10e of the twisting element 10a. In this step Vb, each sleeve 10b, 10c, 10d, 10e must be symmetric about a third symmetry axis 2c that coincides with the second symmetry axis 2b during the twisting step Vb. Subsequently, at least two sleeves 10b, 10c, 10d, 10e are rotated relative to each other from an initial position to a final position, so that the longitudinal portions H of each of at least two groups of pins D are deformed: this deformation is achieved by offsetting the front end E of the pins D circumferentially (i.e., along a substantially circular trajectory) until a different alignment configuration of the radially adjacent portions H is formed in the final position.

[0108] The joining step VI is advantageously carried out by means of a laser welding operation, in which at least one laser source generates at least one corresponding light beam, which advantageously can move along the front end E of the electrical conductors C of the same winding to be welded according to a predetermined pattern.

[0109] This welding can advantageously be carried out by means of a laser, the light beam of which can move along the front end E of the pins D of multiple groups of electrical conductors C to be welded according to programmable movement rules. The laser beam passes through these front ends E along a preset trajectory and at preset time intervals multiple times, so as to liquefy the front ends.

[0110] It should be noted that the method implemented using the workstation 1 according to the present invention does not include any operation of cutting a portion of the electrical conductor C after the first step of preparing multiple electrical conductors C of a predetermined length.

[0111] Advantageously, the present invention solves the above problems by providing the workstation 1 integrated in the device 100 and a method for forming an induction winding of an electric motor. The present invention can easily operate on the grid 3 of the conductor C, where there is no need to cut the pins before joining the pins D together to form a group consisting of at least two pins D.

[0112] The device 100 according to the present invention, the workstation 1 contained therein, and the method can actually use the conductor C of an appropriate length required to provide the winding, thus eliminating the cutting workstations required in most traditional factories (which would result in a significant increase in factory costs, require regular maintenance, consume energy, and generate a large amount of waste conductor C parts).

[0113] Therefore, the device 100 and the method according to the present invention conveniently do not include a cutting workstation for cutting the pins D of the conductor C.

[0114] Advantageously, the device 100, the workstation 1 and the method according to the present invention do not require the use of high-precision machines to perform the following operations: inserting the pins D into the corresponding seats 5 of the forming tool 4 during the formation of the grid 3; and inserting the pins into the slots B of the ferromagnetic core A during the introduction of the grid 3 into the ferromagnetic core A.

[0115] Such high-precision machines are not necessary because the pointed shape of the front end E of the conductor C pin D facilitates its entry into the seats 5 and the slots B.

[0116] Effectively, the device 100, the workstation 1 and the method according to the present invention can ensure the accurate alignment of each front end E with the corresponding seat 5 of the forming tool 4 during the formation of the grid 3 and the accurate alignment of each front end with the slot B of the ferromagnetic core A during the introduction of the grid 3 into the ferromagnetic core A without the need for auxiliary components.

[0117] Such auxiliary components are not necessary because the pointed shape of the front end E of the conductor C pin D facilitates its entry into the seats 5 and the slots B.

[0118] Advantageously, the device 100, the workstation 1 and the method according to the present invention enable the teachings of WO2022136488 to be applied in the final step of joining the individual pins D of the conductor C by means of a welding process.

[0119] More precisely, the device 100, the workstation 1 and the method according to the present invention are easy to implement and are actually implemented, and are cost-effective: these characteristics make the device 100, the workstation 1 and the method according to the present invention an innovation that is bound to be applied.

[0120] The present invention thus conceived is susceptible to various modifications and changes, all of which are within the scope of the appended claims. In addition, all details may be replaced by other technically equivalent elements.

[0121] In the illustrated embodiments, the various features associated with a particular instance can actually be interchanged with other different features present in other embodiments.

[0122] In practice, the materials and dimensions employed can be any materials and dimensions according to requirements and the prior art.

[0123] This application claims priority from Italian Patent Application No. 102022000024435, the disclosure of which is incorporated herein by reference.

[0124] Where reference signs follow the technical features recited in any claim, including these reference signs is only for the purpose of enhancing the intelligibility of the claim and, accordingly, such reference signs have no limiting effect on the interpretation of each element identified by way of example by these reference signs.

Claims

1. A workstation for forming a grid of inductive windings for a hairpin-shaped electrical conductor (C), wherein, Each electrical conductor (C) is fork-shaped and has two straight pins (D) of different lengths joined by a bridging portion (F). The work station (1) comprises: - a forming tool (4) configured to temporarily accommodate a plurality of said electrical conductors (C) around a first axis of symmetry (2a) in order to form the grid (3), wherein the bridging portion (F) of each said electrical conductor (C) is substantially arranged at the same axial height; and - a pushing element (7) configured to move along the first axis of symmetry (2a) to push the grid (3) relative to the forming tool (4). The pushing element (7) comprises a pusher (8) provided with an operating surface (8a), the operating surface being designed to abut against the front end portion (E) of the end of the pin (D) of the electrical conductor (C) forming the grid (3); Characterized in that the operating surface (8a) of the pusher (8) has an annular configuration that is inclined radially, and the protrusion of the operating surface decreases as it gradually moves away from the first axis of symmetry (2a), so as to abut against the electrical conductor (C) at different axial heights in the radial direction. The operating surface (8a) is configured to move axially while maintaining abutment against the front end portion (E) until the operating surface partially lifts the pin (D) of the electrical conductor (C) forming the grid (3) out of the forming tool (4), so that the grid (3) can subsequently be removed from the forming tool (4) by means of a removal element (9).

2. The work station according to claim 1, characterized in that, The operating surface (8a) of the pusher (8) has a configuration selected from at least the following types: frustoconical, hemispherical, spherical, paraboloidal, hyperboloidal and polyhedral.

3. The work station according to claim 1 or 2, characterized in that, The forming tool (4) comprises a body (14) that is symmetric with respect to the first axis of symmetry (2a) and is provided with a plurality of seats (5), each of the seats (5) being configured to accommodate at least one pin (D) of the electrical conductor (C) in a direction parallel to the first axis of symmetry (2a).

4. The workstation according to the preceding claim, characterized in that, The seats (5) are arranged circumferentially and are separated from each other by respective radial partitions.

5. The work station according to one or more of the preceding claims, characterized in that, The forming tool (4) comprises a first surface (15) and an opposite second surface (6). The bridging portion (F) of the electrical conductor (C) forming the grid (3) protrudes from the second surface (6). The pusher (8) is configured to be movable from a first configuration to a second configuration parallel to the first axis of symmetry (2a). In the first configuration, the pusher is arranged at a distance from the second surface (6); compared with the first configuration, the operating surface (8a) of the pusher (8) is closer to the second surface (6) in the second configuration; and wherein the pins (D) of the electrical conductor (C) partially protrude from the second surface (6).

6. An apparatus for forming an induction winding disposed within a through-slot (B) of a ferromagnetic core (A) of an electric motor, characterized in that, The device at least comprises: - a work station (2) for forming a grid of an induction winding according to one of the preceding claims; - A component (9) is taken out, configured to take out the grid (3) of the electrical conductor (C) from the forming tool (4), and then insert the grid into a ferromagnetic core (A) symmetric with respect to a second symmetry axis (2b), such that each pin (D) of the electrical conductor (C) is received in a corresponding slot (B) of the core (A); and - A grouping device (10), configured to re-divide the pins (D) into a plurality of groups, each group in the plurality of groups including at least the pins (D) of the electrical conductor (C) arranged at a substantially same radial distance from the second symmetry axis (2b) in the core (A), the grouping device (10) being dimensioned to act on a longitudinal portion (H) of each pin (D) adjacent to the front end (E).

7. The device according to the preceding claim, characterized in that, The grouping device (10) includes a widening element (12), the widening element being configured and dimensioned such that: first, it can be translated parallel to the second symmetry axis (2b) so as to be inserted into a gap (17) existing between two radially adjacent pins (D) of different electrical conductors (C), so that the longitudinal portion (H) of the pins (D) reaches a predetermined axial height; second, it can also be translated in a radial direction with respect to the second symmetry axis (2b) so as to at least partially deform the portion (H) of the pins (D) in a direction away from the second symmetry axis (2b).

8. The device according to the preceding claim, characterized in that, The widening element (12) includes at least one partition (16), the at least one partition being configured and dimensioned to be axially inserted into the gap (17), wherein the at least one partition (16) includes an edge (18), the edge being configured and dimensioned such that: first, during translation along a direction parallel to the second symmetry axis (2b), the edge faces the front end (E) of the pin (D); second, the edge abuts against a part of the front end (E) of one of the two pins (D) defining the gap (17).

9. The device according to one or more of claims 6 to 8, characterized in that, The grouping device (10) further includes a twisting element (10a), the twisting element including: - at least one first sleeve (10b, 10c) and at least one second sleeve (10d, 10e), the at least one first sleeve and the at least one second sleeve having a circular cross-section, being concentric with each other and mounted to be rotatable about a third symmetry axis (2c) of the twisting element (10a), each of the at least one first sleeve and the at least one second sleeve (10b, 10c, 10d, 10e) being provided with a corresponding channel (10f, 10g, 10h, 10j), the channel being configured to receive a longitudinal portion (H) of the end portion of the pin (D) constituting the electrical conductor (C) to be twisted and the channel being arranged parallel to the third symmetry axis (2c), wherein the third symmetry axis (2c) coincides with the second symmetry axis (2b), and - An element for moving the at least one first sleeve and the at least one second sleeve (10b, 10c, 10d, 10e), the element being configured to rotate the at least one first sleeve (10b, 10c) and the at least one second sleeve (10d, 10e) relative to each other, so as to twist the widened longitudinal portion (H), the sleeves (10b, 10c, 10d, 10e) rotating from an initial position, in which the longitudinal portion (H) retains the shape before being received in the channels (10f, 10g, 10h, 10j), to a final position, in which each portion (H) deformed by twisting the electrical conductor (C) is circumferentially offset until a different alignment configuration of the radially adjacent portions (H) is achieved.

10. The device according to one or more of claims 6 to 9, characterized in that, The device further includes interconnecting means (13) configured to interconnect the longitudinal portions (H) belonging to the same winding, the interconnecting means (13) including a welding unit configured to weld together at least two adjacent end fronts (E) substantially positioned at the same axial height without performing a cutting operation, so that the axial protrusion amounts of the end fronts relative to the ferromagnetic core are equal.

11. A method of forming a grid (3) of electrical conductors (C) of an electric motor winding, wherein, Each electrical conductor (C) is hairpin-shaped, formed to be fork-like, and has two straight pins (D) of different lengths joined by a bridging portion (F), wherein each pin (D) includes a respective end front (E), and the method includes the following steps: - II. Forming an annular grid (3) within a tool (4) for temporarily accommodating the electrical conductors (C) by arranging the electrical conductors (C) within the tool (4) according to a predetermined pattern, wherein the tool has a first axis of symmetry (2a), wherein the electrical conductors (C) are arranged to be received within the tool (4), wherein the end fronts (E) of the pins (D) are located in a radial plane, wherein the longer pin is farther from the first axis of symmetry (2a), and the bridging portion (F) of each electrical conductor (C) is substantially arranged at the same axial height and protrudes from the tool (4); - III. Applying a thrust to the grid (3) relative to the tool (4) by means of a pusher (8), the pusher being movable in the direction of the first axis of symmetry (2a), and the pusher (8) being provided with an operating surface (8a) designed to abut against the end fronts (E) of the pins (D) of the electrical conductors (C) abutting against the grid (3); It is characterized in that the operating surface (8a) simultaneously abuts against the front end part (E) of the electric conductor (C) at different axial heights in the radial direction, and the operating surface (8a) moves axially while maintaining the abutment against the front end part (E) until the operating surface partially lifts the pins (D) of the electric conductor (C) forming the grid from the forming tool (4), wherein the pins (D) remain straight so that the grid (3) can then be removed from the forming tool (4).

12. The method according to the preceding claim, characterized in that, The method includes a preparatory step (I) of preparing a plurality of electric conductors (C), wherein the longer the length of the pin (D), the farther the position taken by the pin in the grid (3) relative to the first symmetry axis (2a).

13. A method for forming an induction winding of an electric motor, the induction winding being of the type arranged in slots (B) of a ferromagnetic core (A) symmetric about a second axis of symmetry (2b), characterized in that, The method includes: - a step of forming a grid (3) of electric conductors (C) according to at least one of claims 11 and 12; - a removal step (IIIa): removing the grid (3) from the forming tool (4) so that the grid (3) can then be inserted into the ferromagnetic core (A).

14. The method for forming an induction winding of an electric motor according to the previous claim, characterized in that, After the removal step (IIIa), the method includes the following steps: - IV. Transferring the grid (3) into the ferromagnetic core (A) and arranging each pin (D) of each electric conductor (C) inside the corresponding through slot (B) of the core (A); - V. Dividing the pins (D) into a plurality of groups, each group in the plurality of groups at least including the pins (D) of the electric conductors (C) arranged at the same radial distance from the second symmetry axis (2b) in the core (A), so as to act on the corresponding longitudinal parts (H) adjacent to the front end part (E) of each pin (D) in the group; - VI. Connecting together the front end parts (E) of the grouped parts (H) belonging to the same winding; wherein, after the grouping step (V), the front end parts (E) of each electric conductor in the electric conductors (C) belonging to different groups have substantially the same axial height in the final position relative to the second symmetry axis (2b), so that before performing the connecting step (VI), there is no need to perform an additional step of cutting the longitudinal parts (H) to make the axial protrusion amounts of the front end parts (E) of the electric conductors (C) inserted into the core (A) equal.

15. The method according to the preceding claim, characterized in that, The grouping step (V) includes a necking step (Va), which includes: by means of a widening element (12) including at least one partition (16), symmetrically deforming the group formed by the longitudinal portions (H) in the radial direction with respect to the second symmetry axis (2b). In the necking step, first, the widening element (12) is moved in a direction parallel to the second symmetry axis (2b) such that the partition (16) of the widening element (12) is axially inserted into the gap (17) defined by two radially adjacent longitudinal portions (H) until a predetermined axial height is reached with respect to the second symmetry axis (2b), and then the widening element is moved in the radial direction with respect to the second symmetry axis (2b) such that the pins (D) of the portions (H) are deformed in the radial direction according to a predetermined geometry.

16. The method according to claim 14 or 15, characterized in that, The grouping step (V) includes a twisting step (Vb). In the twisting step, first, the longitudinal portions (H) of each group of pins in at least two groups of pins arranged at the same radial distance are inserted into at least one corresponding rotating annular sleeve (10b, 10c, 10d, 10e) of a twisting element (10a). Each of the sleeves (10b, 10c, 10d, 10e) is symmetric with respect to a third symmetry axis (2c) coinciding with the second symmetry axis (2b) during the twisting step (Vb), and then at least two of the sleeves (10b, 10c, 10d, 10e) are rotated relative to each other from an initial position to a final position to deform the longitudinal portions (H) of each group of pins in the at least two groups of pins, so that the front ends (E) of the ends of the pins (D) are circumferentially offset until different alignment configurations of the radially adjacent portions (H) are formed in the final position.

17. The method according to at least one of claims 14 to 16, characterized in that, The joining step (VI) is carried out by means of a laser welding operation. In the joining step, at least one laser source generates at least one corresponding beam, and the at least one beam can move along the front ends (E) of the conductors (C) of the same winding to be welded according to a predetermined pattern.

Images