Winding method and machine for winding conductive wire around pole pieces of an electric motor rotor

Abstract

A method and automatic winding machine for forming high-quality windings on the pole pieces of an electric motor rotor using direct in-slot winding technology is described, overcoming problems related to the elasticity of the laminate assembly that defines the rotor body. During winding, the conductive wire is guided by a movable wire guide cap through the rotor slot in which the pole piece to be wound extends. The rotor body is compressed by a pressing device inside the wire guide cap. The axial pressing of the body is performed parallel to the rotor's rotation axis Z to prevent umbrella-shaped deformation. This is achieved by a specific device integrated into the wire guide cap, namely, by utilizing the wire guide cap's internal volume and providing an axial pressing device.

Description

[Technical Field]

[0001] The present invention relates to a method for winding conductive wire onto the pole pieces of the rotor of an electric motor and a corresponding automatic winding machine. [Background technology]

[0002] It is known to manufacture rotors for electric motors having a body made of a plurality of metal laminates stacked together and held together, particularly by overlapping and pressing, the rotor body defining poles or pole pieces around which conductive wire is wound to form the windings.

[0003] The thickness of each laminate is typically a few tenths of a millimeter, e.g., 0.2 mm to 0.4 mm, and the number of laminates stacked is typically several hundred. For example, a rotor body with a height of 150 mm made by stacking laminates with a thickness of 0.35 mm will have more than 400 laminates.

[0004] Because the laminations are manufactured using metal laminate blanking technology, the thickness of the laminations is subject to certain tolerances. This means that the thickness variations between laminations may be very small, for example a few microns, but they still add a non-negligible amount to the overall height of the rotor body. This tolerance must be taken into account by electric motor manufacturers who create the windings of conductive wire on the rotor body.

[0005] Furthermore, it is important to note that laminations have thickness tolerances even at different locations within the same laminate. This can result in imperfect surface overlap across the laminate, leaving tiny gaps between individual laminations, measured in hundredths of a millimeter or even micrometers. As a result, the rotor body behaves elastically and exhibits size variations measurable in millimeters. When the rotor body is not under axial compressive load (i.e., compressive load parallel to the rotor's axis of rotation), the rotor body's height is at its maximum. Conversely, when the rotor body is under axial compressive load, the gaps between each lamination are eliminated, resulting in a decrease in the rotor body's height.

[0006] In other words, by applying an axial compressive load to the rotor body, the laminated plates are properly overlapped, that is, each laminated plate is placed on the entire surface of the underlying laminated plate. When the load is removed, the laminated plate body undergoes a kind of springback, and the laminated plate returns to its original shape, or approximately its original shape, so the height increases.

[0007] In view of the above, it is clear that the height of the rotor body subjected to an axial load is smaller than the height of the same rotor body without an axial compressive load.

[0008] The application of an axial compressive load results from winding a conductive wire around the poles of the rotor body. In fact, a winding tension is applied to the conductive wire before the conductive wire is wound around the poles. That is, the conductive wire is pre-tensioned by a specific wire tension unit arranged on the upstream side of the rotor body with respect to its forward direction. Therefore, if the number of loops effectively wound around the poles of the rotor body increases, the compressive load on the rotor body increases correspondingly. For example, when a small-diameter conductive wire is wound around the poles of the rotor body hundreds of times with a tension of 1 kg, the axial compressive load applied to the rotor body is several hundred kilograms. Therefore, the first loop is wound around the rotor body having an initial height H, and the last loop is wound around the rotor body having a final height h < H. When the winding is completed, while the appropriate tension is applied to the last winding, no tension is applied to the first winding. This is because the first loop is loose and has a certain degree of freedom of movement, and as a result, the winding may be rearranged within the winding and with respect to the poles of the rotor. This may generally degrade the quality of the winding layer and the mechanical and electrical characteristics of the completed rotor.

[0009] The above-mentioned drawbacks are particularly pronounced in rotors with wound poles, and even more so in rotors with unwound poles. This is because the pole pieces are essentially cantilevered relative to the central portion of the rotor body, i.e., the rotating shaft. This exaggerates the elastic behavior of the rotor body itself, resulting in a phenomenon often referred to as "umbrella deformation." When winding the conductive wire around the pole pieces, the number of conductive wires in the windings near the rotor shaft increases radially toward the outside of the rotor, resulting in fewer conductive wires in the windings farther from the shaft. Therefore, the compression caused by the windings does not act uniformly on the pole pieces, being greater at the free ends of the pole pieces compared to the bases of the pole pieces, which are fixed to the rotor shaft. Unless properly corrected, this difference can cause deformation of the lamination assembly, resulting in an "umbrella" shape for the rotor body.

[0010] Two further techniques for winding conductive wire onto the pole pieces of the rotor of an electric motor, and corresponding winding or coil winding machines, are known: - Needle winding: commonly referred to as needle winding technology in English, involves the controlled placement of wire on the pole pieces, with the rotor either stationary or rotating alternately around its axis, using wire-guiding needles that move along the desired laying path in the rotor slots. - Direct in-slot winding: commonly referred to as the in-slot technique in English, this technique uses metal caps to guide the wire into the slots of the rotor. The wire guide caps are attached to the tailstock of the winding machine, which is movable radially relative to the rotor being wound. The wire guide caps move back and forth within the rotor slots to guide the laying of the conductive wire on the pole pieces according to the desired layered winding pattern.

[0011] Typically, when using the needle winding technique, a removable vice is used to prevent umbrella deformation and ensure proper layer winding of the conductive wire. This removable vice is attached to the rotor body before winding to preload the lamination assembly, i.e., apply the axial compressive load necessary to minimize the height of the rotor body. The removable vice used to compact the lamination assembly (which defines the rotor body) typically has two opposing jaws that can be moved toward and away from each other, and a spring positioned between the jaws that constantly applies a restoring force in the direction of moving the jaws toward each other. The spring with an adjustable preload is temporarily extended to fit each vice onto the rotor body. Once the vice is attached to the rotor body, it applies a clamping force to the vice, bringing the jaws toward each other and applying a predetermined axial load to the lamination assembly. In other words, electric motor manufacturers attach a sufficient number of vises to the rotor body before beginning to wind the conductive wire onto the poles. The vises remain attached to the rotor body throughout the winding process and are removed only after winding is complete. This solution allows manufacturers to maintain a constant rotor body height and tension in each loop of conductive wire during winding. The presence of the vises does not interfere with the movement of the wire guide needles. Therefore, the vises are held outside the pole pieces, parallel to the rotor shaft, i.e., axially aligned. The wire guide needles are inserted into the rotor slots along a path that bypasses both the pole pieces and their respective vises. As mentioned above, the vises are removed from the pole pieces only after winding is complete and the wire guide needles are removed. The vises are removed from their storage compartments, attached to the rotor pole pieces, and stored by an automatic device after use.

[0012] However, in direct in-slot winding (in-slot technology), the presence of the tailstock of the winding machine makes it impossible to use the above solution, since it occupies the space that would otherwise be used by the vice. In fact, the tailstock must abut the pole piece in order to extend the wire guide cap into the rotor slot, which is not possible in the presence of a vice.

[0013] JP 2012-135077 A describes a winding machine for direct in-slot winding, in which a tailstock abuts the pole pieces and applies radial pressure to the pole pieces, i.e., pressure perpendicular to the rotor axis of rotation.

[0014] JP 02-111245A describes a machine similar to the one described above, which further includes an anti-rotation element, shown by reference numeral 14 in Figure 2. The anti-rotation element is swallowtail-shaped for engaging the pole pieces with a positive fit, which is used to prevent relative rotation between the laminate assembly and the tailstock. The anti-rotation element is not designed to apply pressure to the pole pieces. Summary of the Invention

[0015] The object of the present invention is to provide a method and an automatic winding machine (coil winding machine) for forming high quality windings on the pole pieces of a rotor by direct in-slot winding techniques, which overcomes the problems associated with the elasticity of the laminate assembly that defines the rotor body of an electric motor.

[0016] A first aspect of the present invention relates to a method according to claim 1.

[0017] During winding, the conductive wire is guided by a wire guide cap which is movable within the slot of the rotor through which the pole piece to be wound at that time extends.

[0018] Advantageously, the method comprises pressing the rotor body by means of a pressing device inside the wire guide cap: the pressing of the body in the axial direction parallel to the rotor axis of rotation Z, in order to prevent umbrella deformation, is achieved by a specific device integrated into the wire guide cap.

[0019] By utilizing the volume inside the wire guide cap to place the pressing device inside, the technical problem is solved, and the rotor body to be wound can be compressed in the axial direction while canceling out the elasticity of the assembly of laminated plates.

[0020] The axial compression applied parallel to the axis of rotation of the completed rotor when winding the conductive wire around the pole pieces minimizes the height of the assembly of metal laminations that make up the rotor body, thereby counteracting the elasticity of the bonds between the metal laminations.

[0021] The axial pressing is preferably performed throughout the entire process of winding the conductive wire around the pole piece, and therefore preferably begins just before the winding begins and ends just after the winding is completed.

[0022] The winding of the conductive wire onto the pole pieces is carried out using an automatic winding machine, for example, the following methods are possible (flyer, rotating spindle):

[0023] - a solution called in-slot flyer winding, in which the rotor body is kept stationary while the wire guide caps are moved alternately in both directions in the rotor slots along a radial approach axis Y relative to the rotation axis Z, and the conductive wires are wound on the wire guide caps and laid on the pole pieces.

[0024] - A solution called rotating shaft in-slot winding, in which the wire guide caps are moved alternately in both directions along the approach axis (Y) in the rotor slots, while the shaft with the rotor body, the wire guide caps and the pressure devices integrated in the wire guide caps are rotated together around the approach axis Y and while being constrained (the pressure devices to the rotor body, and the rotor body to the main shaft).

[0025] In other words, the winding machine can be configured to wind the conductive wire around the wire guide cap and position it correctly on the pole pieces (flyer winding), or to rotate the rotor and the cap together, pull the conductive wire onto the wire guide cap, and then wind it onto the pole pieces (spindle winding).

[0026] Preferably, in the automatic winding machine, the wire guide caps are capable of controlled displacement in both directions along an approach axis Y and radially relative to the rotation axis Z of the rotor supported on the main shaft. The wire guide caps are sized to substantially surround the pole pieces of the rotor, and the pressing device is a vice integrated into the wire guide cap. The method further comprises changing the size of the wire guide caps to fit the pole pieces of the rotor and adjusting the wire guide caps within the rotor slots depending on their instantaneous positions.

[0027] During winding of the conductive wire, the pressing device constantly applies axial pressure to the rotor body, i.e., parallel to the rotation axis Z of the rotor, and the rotor, the wire guide cap, and the pressing device rotate together, i.e., synchronously, about an axis of approach. Once winding is complete, the rotor is kept stationary with respect to an external reference system, while the wire guide cap is detached from the pole piece, i.e., disengaged from the rotor, and the pressing device is deactivated and disengaged from the rotor.

[0028] The axial pressure is preferably applied by the pressing device on the pole pieces of the rotor body.

[0029] The operation of the wire guide cap preferably depends on the activation or deactivation of the pressing device, thereby preventing the winding machine from winding the conductive wire without the rotor body being maintained at its minimum height, i.e., minimum axial extent (axis Z).

[0030] The method can be implemented by making the pressure device adjustable in the axial direction against the rotor body, thereby allowing the winding machine to be adapted to rotors of different sizes, i.e. rotors with different numbers of metal laminations.

[0031] A second aspect of the invention relates to an automatic machine according to claim 10, intended for winding conductive wire onto pole pieces of the rotor of an electric motor.

[0032] The machine comprises: a main shaft or support provided with means for supporting the rotor body; a tailstock movable along an approach axis Y relative to the spindle between a proximal position in engagement with the rotor body supported on the spindle and a distal position in disengagement from the rotor body; a unit for supplying said conductive wire.

[0033] The tailstock is provided with a wire guide cap that is movable relative to the main shaft, and the wire guide cap is movable between a position where the insertion width of the wire guide cap into the rotor slot (particularly the slot through which the pole piece extends) of the rotor body supported by the main shaft is maximum, and a position where the insertion width is minimum or the wire guide cap is disengaged from the rotor slot (and therefore does not engage with the pole piece).

[0034] The winding machine comprises an axial pressing device arranged inside the wire guide cap and configured to press the rotor body in a direction parallel to the axis of rotation Z of the finished rotor, i.e. the axis Z about which the rotor is intended to rotate when assembled with a corresponding stator, thus providing an axial pressing parallel to the height of the pole pieces.

[0035] The internal volume of the wire guide cap is utilized to house the pressing device, which compresses the rotor body to prevent umbrella-shaped deformation while not interfering with the winding of the conductive wire. This proposed solution allows for the formation of higher quality windings without increasing the time, i.e., machine cycles, required for conventional solutions without pressing.

[0036] Preferably, the pressing device is adjustable to apply a calibrated axial pressure to the rotor body, in particular to apply sufficient pressure to overcome the elasticity of the body due to the constraints between each stack of metal laminations, to compress it to a minimum height. Adjusting the axial pressure allows the winding machine to be adapted to rotors of different sizes, thereby increasing the versatility of the machine.

[0037] In a preferred embodiment, the pressure device may be operable throughout the entire winding, ensuring that when the conductive wire is supplied pre-tensioned, the tension in each loop of the winding is equal to the tension in the other loops in the same winding. It may also be considered to disable the pressure device before the winding is complete once a sufficient number of loops have been wound on the pole pieces so that the rotor body is no longer subjected to the spring return of the metal laminations.

[0038] In a first embodiment, when the winding machine is in use, the rotor body is kept stationary within the main shaft or support (relative to an external reference system, e.g., the environment in which the machine resides), while the wire guide caps are moved alternately in both directions within the rotor slots along the approach axis Y. The conductive wire is provided by the feed unit and wound onto the wire guide caps, thereby laying them on the pole pieces. In practice, the feed unit rotates about the approach axis Y, guiding the conductive wire onto the wire guide caps while the wire guide caps are moving within the rotor slots, and positioning the conductive wire in the appropriate position.

[0039] In a second preferred embodiment, while the winding machine is operating, the wire guide cap moves alternately in both directions in the rotor slot along the approach axis Y. At the same time, the machine rotates the main shaft, the rotor body, the wire guide cap and the pressing device integrated in the wire guide cap together around the approach axis Y. Thus, in the above embodiment, the feeding unit that feeds the conductive wire does not move, and the wire guide cap that rotates around the approach axis Y draws in the conductive wire.

[0040] The rotor body is preferably supported on the main shaft or support such that the rotation axis Z of the rotor is perpendicular to and intersects the approach axis Y. The wire guide cap is capable of controlled displacement in both directions along the approach axis Y. The wire guide cap is sized to substantially surround the rotor pole pieces wound with the conductive wires. The pressing device is a vice integrated into the wire guide cap, i.e., located inside the wire guide cap, which functions synergistically to apply axial pressure parallel to the rotation axis Z of the rotor to the assembly of laminates.

[0041] It is preferable that the main shaft, the rotor body supported thereon, the wire guide cap, and the vise integrated into the wire guide cap are rotatable integrally, i.e., as a whole, about the approach axis Y.

[0042] Rotation of the wire guide cap and the vice about the axis of approach Y preferably depends on the action of the vice on the edge of at least one pole piece of the rotor body, so that the laying of the conductive wire is performed with the rotor body in axial compression and with guaranteed absence of umbrella deformation.

[0043] In a preferred embodiment, the pressing device is a vice. The vice includes two jaws that are movable radially relative to the axis of approach Y, and thus parallel to the axis of rotation Z of the rotor supported on the main shaft. The jaws are movable between a distal position, corresponding to an open state of the vice, and a proximal position, corresponding to a closed state of the vice. When the vice is open, it can disengage from and engage with the rotor body. When the vice is closed, the jaws apply pressure to the rotor body, compressing it to a minimum axial extent (with respect to axis Z).

[0044] The vise may be of various types, for example hydraulic, but is preferably mechanical, and the vise actuator is attached to the tailstock. The actuator comprises a drive shaft extending on the approach axis Y, a lever system fixed to the jaws, and one or more springs that constantly exert a return force that returns the jaws to a closed position proximal to the vise. With this arrangement, the vise is normally in a closed position and is temporarily moved to an open position by the intervention of an actuator. The machine can further comprise an inverse kinematics, i.e., a spring that tends to open the vise and an actuator that keeps it closed. The operation of the vise causes the drive shaft to move on the approach axis Y, a position in which the lever system resists the action of the spring to maintain the jaws in a distal open position of the vise, the engaged position of the lever system; and a disengaged position in which the drive shaft does not exert sufficient thrust on the lever system to overcome the action of the spring and the jaws are in a proximal closed position of the vise. The alternating movement of the drive shaft of the vise along the approximation axis Y can be provided, for example, by an electric linear actuator.

[0045] In an alternative embodiment, movement of the vise may be achieved by an actuator that moves radially relative to the axis of rotation.

[0046] In a preferred embodiment, the wire guide cap is mounted on a rotating shaft rotatable on the approach axis Y. The drive shaft of the vise is coaxially disposed within the rotating shaft of the wire guide cap. As will become more apparent below, this configuration allows the drive shaft of the vise and the rotating shaft of the wire guide cap to rotate synchronously when the conductive wire is wound onto the pole pieces of the rotor, and allows the drive shaft of the vise to move relative to the rotating shaft of the wire guide cap along the approach axis Y when the vise needs to be opened to release the rotor.

[0047] In this manner, this configuration in which each actuator shares an internal volume of space within the wire guide cap allows the vise to be integrated into the wire guide cap, without the vise occupying any external space of the wire guide cap.

[0048] The wire guide caps have a variable shape and can be adjusted in size to match the shape of the pole pieces during winding, in particular to fit the rotor slots as they move along the approach axis Y and radially relative to the rotor axis of rotation Z between minimum and maximum insertion positions. The wire guide caps have a generally conical shape, so unless the shape of the wire guide caps is variable, interference will occur and they will not be able to be fully inserted into the rotor slots.

[0049] The wire guide cap is made up of two halves arranged on opposite sides of a pressing device, i.e., the vice, which are movable radially towards and away from each other relative to the approach axis Y, allowing the size of the wire guide cap to be changed and its insertion into the rotor slot.

[0050] In operation of the winding machine, the rotor body is placed on the main shaft with the pole pieces positioned facing the tailstock. Before starting rotation of the main shaft and the rotor body, the tailstock is placed against the stationary pole pieces of the rotor body around which the conductive wire is to be wound, and the pressing device (vice) is activated to compress the rotor body. The main shaft is started to rotate the rotor body about the approach axis Y, and at the same time, the tailstock rotates integrally with the main shaft and the rotor body. The conductive wire slides on the outer surface of the wire guide cap and is laid down by moving back and forth within the rotor slots according to the predetermined winding pattern, continuing until the winding is complete. Once the winding is wound around the pole pieces, the main shaft and the tailstock are stopped, i.e., rotation about the approach axis Y is interrupted, the pressing device is released, and the rotor body is released. The tailstock is moved away from the main shaft and the rotor body rotates about its axis of rotation Z to present a new pole piece opposite the tailstock in preparation for the next winding cycle. [Brief explanation of the drawings]

[0051] Further features and advantages of the present invention will become apparent from a consideration of the following detailed description, taken in conjunction with the accompanying drawings, which illustrate preferred embodiments by way of example and without limitation, in which: [Figure 1] FIG. 1 is a perspective view and an elevation view of a rotor made using the method and machine of the present invention, the rotor having wound poles. [Figure 2] FIG. 2 is a cross-sectional front view of a portion of the rotor, particularly one of its pole pieces, in combination with a vise and prepared for winding conductive wire according to known needle winding techniques. [Figure 3] 3 is a bottom perspective view of a portion of the rotor and a vice shown in FIG. 2. FIG. [Figure 4] 4 is a bottom view of a portion of the rotor and a vice shown in FIG. 2. FIG. [Figure 5]FIG. 5 is a front perspective view of a needle winder (coil winder) according to known technology and a rotor having pole pieces wound with conductive wire. [Figure 6] FIG. 6 is a perspective view showing a winding machine (coil winding machine) according to the present invention. [Figure 7] FIG. 7 is a top view of the machine shown in FIG. [Figure 8] 8A and 8B are a front view and a front cross-sectional view showing the first part of the machine shown in FIG. 6, which is the main shaft and the rotor to be wound. [Figure 9] FIG. 9 is a side view, a front view, and a partial cross-sectional view showing the main shaft portion of the machine shown in FIGS. [Figure 10] FIG. 10 is a plan view, a top view, and a partial cross-sectional view of the spindle portion of the machine shown in FIGS. 6 and 8. [Figure 11] FIG. 11 is an isometric view of the spindle portion of the machine shown in FIGS. 6 and 8. [Figure 12] FIG. 12 is a perspective view and a front view of the tailstock, which is the second part of the machine shown in FIG. [Figure 13] FIG. 13 is a vertical cross-sectional view of the tailstock of the machine shown in FIGS. 6 and 12. [Figure 14] 14 is a sectional plan view of the tailstock of the machine shown in FIGS. 6 and 12, taken along section BB in FIG. [Figure 15] FIG. 15 is an isometric and vertical (axial) cross-sectional view of the tailstock of the machine shown in FIGS. 6 and 12. [Figure 16] FIG. 16 is a cross-sectional plan view of the machine shown in FIG. 6 illustrating a first configuration for the process of laying conductive wire to the pole pieces of the rotor of the electric motor. [Figure 17] FIG. 17 is a cross-sectional plan view of the machine shown in FIG. 6 illustrating a second configuration for the process of laying conductive wire to the pole pieces of the rotor of the electric motor. [Figure 18] FIG. 18 is a cross-sectional plan view of the machine shown in FIG. 6 illustrating a third configuration for the process of laying conductive wire to the pole pieces of the rotor of the electric motor. [Figure 19] FIG. 19 is a cross-sectional plan view of the machine shown in FIG. 6 illustrating a fourth configuration for the process of laying conductive wire to the pole pieces of the rotor of the electric motor. [Figure 20] Figure 20 is a vertical (axial) cross-sectional view of the tailstock of the machine shown in Figures 6, 12 and 16 to 19, showing a first configuration for the process of laying conductive wires on the pole pieces of the rotor of an electric motor. [Figure 21] Figure 21 is a vertical (axial) cross-sectional view of the tailstock of the machine shown in Figures 6, 12 and 16 to 19, showing a second configuration for the process of laying conductive wires on the pole pieces of the rotor of an electric motor. [Figure 22] Figure 22 is a vertical (axial) cross-sectional view of the tailstock of the machine shown in Figures 6, 12 and 16 to 19, showing a third configuration for the process of laying conductive wires on the pole pieces of the rotor of an electric motor. [Figure 23] Figure 23 is a vertical (axial) cross-sectional view of the tailstock of the machine shown in Figures 6, 12 and 16 to 19, showing a fourth configuration for the process of laying conductive wires on the pole pieces of the rotor of an electric motor. Detailed Description of the Invention

[0052] 1 shows a rotor 1 with wound poles for assembling an electric motor. The rotor 1 comprises a body 2 having a shaft 3 that rotates about a rotation axis Z, and a plurality of pole pieces 4 extending radially from the rotating shaft 3 and defining rotor slots 5 therebetween.

[0053] The body 2 of the rotor 1 is an assembly of stacked metal laminations, with reference numeral 6 indicating a single lamination, particularly the top lamination. A winding 7 of conductive wire 8 (e.g., copper wire) is formed around each pole piece 4.

[0054] The rotor 1 as shown in FIG. 1 can be formed by needle winding or in-slot techniques.

[0055] 5 shows a winding machine (coil winding machine) 9 according to known technology, which comprises two wire guide needles 10 fed with a conductive wire 8 and which moves around the pole pieces 4 and within the rotor slots 5 to lay the conductive wire according to the desired layered winding pattern to form the windings 7. The vertical movement of the wire guide needles 10 (axial movement parallel to the axis Z of the rotor 1) is synchronized with the alternating rotational movement of the rotor body 2 about the axis Z.

[0056] 2 to 4 show a portion of the rotor 1, particularly the pole pieces 4 of the rotor 1, when the windings 7 are being formed by a needle machine 9 shown in FIG. 5. As shown in FIGS. 2 to 5, at the pole pieces 4, the rotor body 2 is compressed by a vice 11 that clamps the stack of metal laminate plates 6 that make up the rotor body 2 in the axial direction (axis Z) to compress it in the axial direction. As can be seen from FIG. 5, a corresponding vice 11 is attached to every pole piece 4 of the rotor 1, which prevents the aforementioned umbrella-shaped deformation from occurring during winding by the needle machine 9. Each vice 11 has two jaws 12' and 12" that are movable in the axial direction. These jaws 12' and 12" move away from each other to open the vice 11 and move toward each other to tighten the vice 11. The clamping force is applied by a spring disposed inside the vice 11, and the preload can be adjusted by a screw 13. As explained with respect to the known art, the vice 11 is initially open and is pre-attached to each of the pole pieces 4 of the rotor 1 before the rotor 1 is placed in the machine, i.e. before the body 2 of the rotor 1 is placed in the winding machine 9 and the pole pieces 4 are wound with the conductive wire 8. Once this process is completed and the windings 7 are formed on the rotor 1, the rotor 1 is removed from the machine 9 and the vice 11 is opened and removed from the body 2 of the rotor 1.

[0057] 2 to 5, it can be seen that the size of the vice 11 cannot be ignored. This size does not prevent the wire guide needles 10 from being inserted into the rotor slots 5, and therefore does not cause any problems when performing winding with a needle machine such as machine 9, but it is not compatible with winding methods using the in-slot technique, in which a metal wire guide cap is inserted into the rotor slots 5 and the rotor body 2 is rotated around an axis perpendicular to axis Z.

[0058] This is where the present invention of a winding method and machine using in-slot technology, capable of forming high quality windings on a rotor having wound poles without the use of a vice 11, is useful.

[0059] 6 and 7 show the entirety of an automatic winding machine (coil winding machine) 14 for in-slot winding according to the present invention.

[0060] The automatic winding machine 14 (hereinafter simply referred to as the machine 14 or the winding machine 14) is composed of three main units: a spindle unit 15 and a tailstock unit 16 (hereinafter simply referred to as the spindle 15 and the tailstock 16), and a supply unit 17 that supplies conductive wire.

[0061] The supply unit 17 includes a wire guide tube 18 through which the conductive wire is fed from a wire tensioning device 19 that maintains the conductive wire at a nominal tension throughout the winding process of the rotor 1. The supply unit 17 is located above the spindle 15 and tailstock 16, and the wire guide tube 18 is generally aligned with the end of the tailstock 16.

[0062] The main shaft 15 and the tailstock 16 face each other across the rotor 1, i.e., are positioned diametrically opposite each other with respect to the rotation axis Z of the rotor 1. The main shaft 15 is provided with a fork 19 that locks the body 2 of the rotor 1 during winding of the conductive wire. The fork 19 is rotated by the main shaft 15 around an axis Y, which serves as an approach axis Y perpendicular to the rotation axis Z of the rotor 1. Rotation of the rotor 1 about the axis Y causes the pole pieces 4, which occasionally face the tailstock 16, to rotate like spools, onto which the conductive wire can be wound with the desired number of loops and in the desired layered winding pattern. Once a pole piece 4 is completed, i.e., once the winding 7 is completed, the rotor 1 rotates around the fork 19 around the axis Z, bringing a new pole piece 4 into contact with the tailstock and starting winding. The rotation of the rotor about axis Z relative to the fork 19 is intermittent, and when the rotor 1 is not rotating about axis Z, it is rotated about axis Y to wind one of the pole pieces 4, and vice versa, until all windings 7 are completed. The rotation of the fork 19, and therefore of the rotor 1 about axis Y, is controlled by an electric motor M1.

[0063] The tailstock 16 has different functions as described below.

[0064] The tailstock 16 is provided with a metal cap 20 which is used to guide the conductive wire 8 to the pole piece 4 during the winding process. To this end, the wire guide cap 20 (hereinafter simply referred to as cap 20) is movable along the axis Y, and thus radially relative to the rotating shaft 3 of the rotor 1, and alternately in both directions relative to the same tailstock 16, and is inserted into the rotor slots 5 to surround the pole piece 4 and guide the conductive wire 8 while the rotor 1 is rotating about the axis Y, to form the desired layered winding.

[0065] Figures 8-11 show the spindle 15 in more detail. In particular, Figure 8 is a front and elevational view of the spindle 15 with the rotor 1 inserted into the fork 19, as seen from the tailstock. Figure 9 is a side view, elevational view, and partial cross-sectional view of the spindle 15 with the rotor 1 locked to the fork 19. Figure 10 is a top view and partial cross-sectional view of the spindle 15 with the rotor 1 locked to the fork 19. Note that the releasable fork 19 securely holds the rotor 1 to prevent undesired movement of the rotor 1 relative to the fork 19. Once the winding 7 on the pole piece 4 shown in Figure 8 is complete (pole piece 4 facing the tailstock 16), the fork 19 partially opens, the rotor rotates about axis Z to move the new pole piece 4 into the position shown in Figure 8, and the fork 19 closes again to begin forming the new winding 7 using conductive wire. Figure 11 is a perspective view of the spindle 15 and rotor 1. In addition to opening the forks 19, the main shaft 15 is provided with a linear actuator 21 for pressing the rotor against the ends of the forks 19 to lock the rotor 1 together with the forks 19. Rotation about axis Y is indicated by the arrows shown in Figures 8 and 11 and may be counterclockwise as shown, or clockwise.

[0066] In summary, the tailstock 16 is movable along axis Y towards or away from the spindle 15, and the rotor 1, which is disposed on the spindle 15 and has an axis of rotation Z perpendicular to axis Y, is caused to rotate clockwise or counterclockwise about axis Y.

[0067] 12 to 15 show the tailstock 16. In particular, FIG. 12 is a perspective view of the tailstock 16 from the side facing the main shaft 15, i.e., toward the rotor 1 and one of its pole pieces 4, the pole piece through which the conductive wire is laid. As can be seen, a metal cap 20 is attached to the tailstock 16 and is movable along axis Y toward and away from the main shaft 15 along with and / or relative to the tailstock 16. The cap 20 is shaped to be inserted into the rotor slot 5 of the rotor 1, surround the pole piece 4, and engage with two rotor slots 5 located to the left and right of the pole piece 4. For this reason, the cap 20 extends primarily in the height direction, parallel to the rotor 1.

[0068] The tailstock 16 is movable between a retracted position where it is completely removed from the rotor 1 and an abutment position, which is an advanced position where the tailstock abuts the pole piece 4 of the rotor 1 shown in Figures 8 and 11, i.e., the pole piece 4 accessible via the fork 19 in the Y direction.

[0069] The cap 20 is movable between an advanced position where the rotor 1 is inserted into the rotor slot 5 to the maximum extent and a retracted position where the rotor 1 is inserted into the rotor slot 5 to the minimum extent.

[0070] The winding of the conductive wire 8 onto the pole pieces 4 is performed with the caps 20 inserted into the rotor slots 5. The desired layered winding of the conductive wire 8 onto the pole pieces 4, and thus the desired shape of the windings 7, is achieved by appropriately controlling the alternating movement of the caps 20 along the axis Y between advanced and retracted positions.

[0071] The tailstock 16 further comprises an internally integrated vice 22, which is inserted in particular in the cap 20 and serves to compact the pole pieces 4 on the body 2 of the rotor 1 while the winding is taking place.

[0072] The vice 22 is movable between a proximal position and a distal position and has jaws 23 and 24 for compacting and releasing the body 2 of the rotor 1. As can be seen from Figure 12, the jaws have a concave shape that corresponds to the convex shape of the radial outer surface of the pole piece 4 of the rotor 1, allowing the tailstock 16 to abut against the pole piece 4 and press the jaws 22 and 23 against the pole piece 4.

[0073] When the rotor slot 5 extends radially relative to the shaft 3 of the rotor 1, the shape of the cap 20 can be modified to allow it to be inserted into the slot 5, i.e., to fit the shape of the slot 5. In particular, the cap 20 is formed by two halves 20' and 20" located on opposite sides of a vise 22. The two halves 20' and 20" of the vise 22 are movable toward and away from each other and relative to the vise 22 located intermediate them, such that when the cap 20 moves from the retracted position to the advanced position, the two halves 20' and 20" move toward each other, correspondingly toward the angle formed at the center by the windings 7 on the pole pieces 4, and conversely, when the cap 20 moves from the advanced position to the retracted position, the two halves 20' and 20" move away from each other.

[0074] Therefore, the formation of the windings 7 on the pole pieces 4 of the rotor 1 is - an operation for rotating the main shaft 15 and the rotor 1 about the axis Y; - moving the cap 20 back and forth radially on the axis Y relative to the rotation axis X of the rotor 1; - This can be achieved by combining the action of opening and closing the cap 20, i.e. the action of opening and closing the halves 20' and 20''.

[0075] The operation of the tailstock 16, and particularly the operation of the cap 20 and vice 22, will now be described in detail with reference to the remaining figures.

[0076] 13 shows a vertical cross section and an elevation view of the tailstock 16. That is, the cross section is taken on a vertical plane passing through the rotation axis Z of the rotor 1 (before it has rotated about the axis Y) as shown in FIGS. 6 to 11. The cross section is also the plane of symmetry of the vice 20.

[0077] The vise 20 is further provided with a drive shaft 25 disposed along an axis Y for driving the jaws 23, 24. The drive shaft 25 has a first end inserted into the body of the tailstock 16, which is supported by bearings, and a wedge-shaped second end for engaging an articulated quadrilateral lever system 27. Such lever system 27 is hingedly connected to both the body of the tailstock 16 and the jaws 23, 24, - forcing the wedge-shaped end 26 into the lever system 27 (thrust applied by the actuator) opens the vise 20, i.e. moves the jaws 23, 24 apart; a similar result can be achieved by a toggle mechanism; Returning the drive shaft 25 to its initial position causes the vise 20 to self-close, i.e. the vise 23, 24 to move towards each other by means of a preload spring (not shown in FIG. 3).

[0078] With this configuration, the jaws 23, 24 are firmly pressed against and held by the assembly 6 of laminated plates that constitutes the body 2 of the rotor 1 at the position of the pole piece 4, thereby preventing umbrella-shaped deformation.

[0079] Because the tailstock 16 must rotate about axis Y to wind the conductive wire, the drive shaft 25 is mounted for rotation about axis Y. An actuator controls the displacement of the drive shaft 25 along axis Y, and rotation is imparted by another component described below. That is, while the conductive wire 8 is being laid, the drive shaft 25 is driven to rotate about axis Y.

[0080] The drive shaft 25 is coaxially inserted into the rotating shaft 28 of the cap 20, and the rotating shaft 28 has the function of driving the cap 20 to rotate about the axis Y in synchronization with the rotation of the rotor 1 about the axis Y. During this rotation, the rotor 1 rotates about the axis Y together with the fork 19 and the cap 20. To be precise, the rotating shaft 28 of the cap 20 also rotates the drive shaft 25 of the vice 22. Furthermore, the shaft 25 slides inside the shaft 28 to open and close the vice 20.

[0081] FIG. 14 shows the tailstock 16 in a plan view, a top view and a partial cross section on the plane BB of FIG. 13. FIG. 15 shows the tailstock 16 in a perspective view and a vertical cross section (elevation). Inside the cap 20, an actuator 29 for actuating the two halves 20' and 20" of the cap 20 is arranged between the vice 22 and the body of the tailstock 16. The actuator 29 has guides or tracks 32 arranged inclined to the axis Y, which are inclined relative to each other at an angle (for example, 60°) corresponding to the angle formed by the pole pieces of the rotor to be machined (360° / 6=60° for 6 poles, 360° / 8=45° for 8 poles). The guides 32 engage with corresponding guides 33 in the halves 20' and 20" of the cap 20. Movement of the actuator 29 along the axis Y displaces the guide 32, which exerts a thrust on the guides 33 of the two halves 20' and 20" of the cap, thereby controlling their opening and closing. In this way, the cap 20 can expand and contract to fit the available space depending on the position of the rotor slots 5.

[0082] 16 to 19 show, in time sequence, the operation of inserting caps 20 into rotor slots 5 of rotor 1 mounted on main shaft 15. In particular, these figures are plan and cross-sectional views of winding machine 14, the cross-sectional view being taken on a horizontal plane that includes axis Y and is perpendicular to axis Z.

[0083] In the state shown in Figure 16 (standby configuration), the spindle 15 and tailstock 16 face each other and are spaced apart along the axis Y. The tailstock 16 is held in place by the spindle 15 and is in a retracted position ready to abut the locked rotor 1 between the fork 19 and the actuator 21. The rotor 1 is stationary in this configuration. A single pole piece 4 is accessible to the tailstock 16 from the outside of the fork 19, with the pole 4 facing away from the fork 19. If necessary, the rotor can be unlocked to allow partial rotation and then relocked once a new pole piece 4 is aligned with the tailstock 16.

[0084] In the configuration shown in FIG. 17 (engaged configuration), the tailstock 16 is shown in an abutting position. The body of the tailstock 16 has moved forward toward the spindle 15, and the two halves 20′ and 20″ of the cap 20 surround the end of the pole piece 4 that is furthest from the rotating shaft 3 of the rotor 1. The vice 22 abuts the outer surface of the pole piece 4 and is complementary in shape to it. The rotor 1, fork 19, and tailstock 16 are all stationary. The vice 22 is open, i.e., the drive shaft 25 is in the forward position and the wedge-shaped end 26 is inserted into the lever system 27, and in this state the jaws 23 and 24 are in an open distal position. The jaw 23 is above the metal lamination assembly 6 that defines the body 2 of the rotor 1, and the jaw 24 is below the lamination assembly 6.

[0085] In the configuration shown in FIG. 18 (compression configuration), the vise 22 is closed, i.e., the jaws 23 and 24 are close together and clamp the assembly 6 of laminations that make up the body 2 of the rotor 1. In this way, compression of the body 2 of the rotor 1 is achieved, at least at the pole piece 4 against which the tailstock 16 abuts. As can be seen by comparing FIGS. 17 and 18, closing the vise 22 is achieved by moving the drive shaft 25 of the vise 22 rearward relative to the body of the tailstock 16. As the drive shaft 25 moves rearward, the wedge-shaped portion 26 also moves rearward, causing the lever system 27 to be pushed back by a restoring force provided by a spring (not shown) that moves the jaws 23 and 24 to their proximal positions. In this configuration, the body 2 of the rotor 1 is compressed in the same manner as in the prior art configuration shown in FIGS. 2-4. That is, instead of attaching an external vice 11 to the pole piece 4, a vice 22 integrated into the tailstock 16 of the winding machine is used to prevent umbrella deformation. This vice 22 is actuated by the same actuator as the tailstock 16, rather than an external actuator.

[0086] When the body 2 of the rotor 1 is compressed, the winding of the conductive wire 8 begins.

[0087] In the configuration shown in Figure 19 (layered winding configuration), the machine 14 is shown during winding. Imagine the rotor 1 in the same position as in Figures 16-18, but rotating clockwise or counterclockwise about axis Y. As previously described, the rotor is rotated about axis Y by the main shaft 15 while locked between the fork 19 and the linear actuator 21. As the body 2 of the rotor 1 rotates about axis Y, the vice 22 keeps the pole pieces 4 clamped, rotating together with the rotor 1 about axis Y. Therefore, during rotation, the body 2 of the rotor 1 does not expand axially, i.e., in a direction parallel to the axis Z of the rotor 1, due to the spring return of the lamination assembly 6. As the body 2 of the rotor 1 rotates about axis Y, the tailstock 16 is displaced alternately in both directions along the same axis Y, resulting in the metal caps 20 being inserted into the rotor slots 5 defining the pole pieces 4 and the conductive wire being wound around their sides.

[0088] This alternating movement of the cap 20 when it is inserted into or removed from the rotor slot 5 is indicated by the arrow W in FIG. 19. Since the rotor slot 5 extends substantially radially, it is not a simple translational movement. The two halves 20' and 20" of the cap 20 must move towards and away from each other, i.e., towards and away from the axis Y, to fit into the rotor slot 5 during the forward movement of the cap 20. This prevents interference with the rotor body 2 and allows the conductive wire 8 to follow the path required to achieve the desired layered winding.

[0089] The cap 20 therefore undergoes several movements, including a back and forth movement along the axis Y, an opening and closing movement, i.e., a movement of the halves 20' and 20" towards and away from each other, and also a rotational movement about the axis Y, taking into account that during winding the cap 20, like the vice 22, rotates integrally with the body 2 of the rotor 1.

[0090] Referring to Figure 19, it can be imagined that the conductive wire 8 is continuously fed by the feed unit 17 through the wire guide tube 18 and extends perpendicular to the plane of Figure 19 in a pre-tensioned state. During winding, the conductive wire 8 abuts against the cap 20, which guides it into laying on the rotating pole piece 4. The cap 20 moves back and forth along the axis Y, winding the conductive wire 8 in layers. Figure 19 shows a cross-sectional view of the conductive wire 8 (not to scale for instructional purposes).

[0091] Once the winding 7 is completed, the machine 14 stops the rotation of the main shaft 15, returns the rotor 1 to the vertical axis Z, retracts the tailstock 16, withdraws the caps 20 from the rotor slots 5, and releases the vice 22. The rotor 1 is now rotated about the axis Z, causing new pole pieces 4 to interact with the tailstock 16 as previously described, forming the winding 7.

[0092] The above process is repeated for all pole pieces 4 until the rotor 1 is completed.

[0093] Figures 20 to 23 are vertical cross-sectional views, i.e., elevation views, of a portion of the tailstock 16 and spindle 15 in the four configurations shown in Figures 16 to 19. In other words, Figures 16 and 20, 17 and 21, 18 and 22, and 19 and 23 correspond to each other, and show the four work steps of waiting, engaging, pressing, and layer winding in chronological order.

[0094] 20 shows the machine 14 in a standby configuration, with the drive shaft 25 of the vise 22 in an advanced position. The vise 22 has been opened under the influence of a force from a lever system 27 acting from a wedge-shaped end 26 of the drive shaft 25, with the jaws 23 and 24 in a wide-open, distal position. In this configuration, the jaws 23 and 24 are sufficiently spaced apart to allow the lamination assembly 6 making up the body 2 of the rotor 1 to be inserted therebetween at the pole piece 4. The tailstock 16 is spaced from the spindle 15 and rotor 1, ready for proximity placement.

[0095] 21 shows the machine 14 in an engaged configuration. The tailstock 16 advances along axis Y to a position where the vise 22 abuts the side 4' of the pole piece 4, which is stationary with the spindle 15. Jaws 23 and 24 surround the metal laminate assembly 6.

[0096] 22 shows the machine 14 in a configuration for pressing the rotor 1. The drive shaft 25 of the vise 22 is retracted from the position shown in the previous figure by an actuator, so that the wedge-shaped end 26 is disengaged from the lever system 27. The closing movement of the vise 22, i.e., the displacement of the jaws 23 and 24 to their proximal position and the consequent pressing of the laminate assembly 6, is achieved by no longer resisting the action of the spring. The spindle 15 and tailstock 16 are stationary at this stage in the direction of the axis Y, so that no umbrella-shaped deformation of the body 2 of the rotor 1 occurs.

[0097] FIG. 23 shows the machine 14 in a layered winding configuration, i.e., during winding. The spindle 15 and tailstock 16 rotate together (synchronously) about axis Y, while the vice 22 remains clamped to maintain the body 2 of the rotor 1 in compression. The conductive wire 8, supplied from the supply unit 17 and pretensioned by the wire tensioner 19, is continuously fed into the tailstock 16, and in particular into the cap 20. For example, as shown in FIG. 23, to achieve the desired layered winding, the rotor 1 rotates about axis Y, and the vice 22 presses against the body 2, while the tailstock 16 and / or the cap 20 moves in both directions along axis Y to guide the conductive wire 8, so as to create fewer loops near axis Z of the pole piece 4 and more loops in sectors further from axis Z. During the alternating movement of the cap 20 along axis Y, the vice 22 always remains clamped against the body 2 of the rotor 1, preventing umbrella-shaped deformation. The cap 20 moves in both directions along the axis Y and simultaneously rotates about the axis Y together with the main shaft 15 and the rotor 1. Once winding 7 is complete, the procedure is repeated until all windings on the rotor 1 are completed.

[0098] This winding machine 14 does not use an external vice, which is large in size and prevents the tailstock 16 from abutting against the side 4' of the pole piece 4, but instead uses a vice 22 that is integrated into the tailstock, i.e., located inside the cap 20 and operated by an actuator shared with the cap 20, thereby enabling in-slot winding of the rotor 1 by inserting the cap 20 between the pole pieces 4 in the rotor slot 5.

[0099] The integration of the vise 22 and cap 20 allows for the use of a drive shaft 25 for operation of the vise 22 (via a spring and lever system 27) and a rotating shaft 28 for the cap 20. The shafts 25 and 28 are coaxial with axis Y, with the drive shaft 25 inside the rotating shaft 28. The two shafts are interdependent, and when the vise 22 is open, the drive shaft 25 slides, or translates, inside the rotating shaft 28. When the vise 22 compacts the body 2 of the rotor 1, the two shafts 25 and 28 rotate together.

[0100] By utilizing the internal volume of the cap 20, space for the vice 22 can be secured without excessively complicating the structure of the tailstock 16, and the problem of umbrella deformation can be solved even in the in-slot winding method.

[0101] The solution of integrating the vice 22 inside the cap 20 can also be applied to another embodiment of the winding machine, in which the conductive wire 8 is wound while the body 2 of the rotor 1 remains stationary on the main shaft 15. That is, the body 2 of the rotor 1 is not rotated about the axis Y, and therefore neither are the cap 20 nor the vice 22, but a rotation system for the conductive wire 8, which rotates about the axis Y, is used to wind the conductive wire 8 onto the cap 20, which guides its laying on the pole pieces 4. In this embodiment, which is not shown, the main shaft 15 can simply be a non-rotating support, and the feed unit 17 rotates about the approach axis Y to wind the conductive wire 8 onto the wire guide cap 20, which controls the laying path of the winding 7 around the pole pieces 4.

Claims

1. 1. A method for winding windings (7) of a conductive wire (8) around pole pieces (4) of a rotor (1) of an electric motor by in-slot technique, wherein the conductive wire (8) is guided during winding by wire guide caps (20) movable in slots (5) of the rotor through which the pole pieces (4) extend, characterized in that the body (2) of the rotor (1) is pressed axially by a device (22) inside the wire guide caps (20).

2. 2. The method according to claim 1, wherein the body (2) of the rotor (1) is made of a stack of metal laminates (6), and when the conductive wires (8) are wound around the pole pieces (4), the body (2) is pressed axially parallel to the rotation axis (Z) of the rotor (1) to counteract the elasticity of the bonds between the metal laminates (6) and keep the height of the stack of the metal laminates (6) to a minimum.

3. 3. A method according to claim 1 or 2, characterized in that the pressing is performed throughout the process of winding the conductive wire (8) around the pole piece (4).

4. 10. A method according to any one of the preceding claims, wherein winding the conductive wire (8) around the pole piece (4) is carried out using an automatic winding machine (14): - keeping the body (2) of the rotor (1) stationary while simultaneously moving the wire guide caps (20) alternately in both directions along the approach axis (Y) in the slots (5) of the rotor, winding the conductive wires (8) on the wire guide caps (8) and laying them on the pole pieces (4), or - moving the wire guide cap (20) alternately in both directions along the approach axis (Y) in the rotor slot (5), while simultaneously rotating the main shaft (15) carrying the body (2) of the rotor (1), the wire guide cap (20) and the pressing device (22) integrated in the wire guide cap (20) simultaneously and integrally around the approach axis (Y).

5. 5. The method of claim 4, wherein the rotor (1) has a rotation axis (Z), and in the automatic winding machine (14), the wire guide cap (20) is capable of controlled displacement in both directions along the approach axis (Y) and in a radial direction relative to the rotation axis (Z) of the rotor (1), the wire guide cap (20) has a size that substantially surrounds the pole pieces (4) of the rotor (1), and the pressing device (22) is a vice integrated in the wire guide cap (20).

6. 6. The method of claim 5, During the winding of the conductive wire (8), the vice (22) constantly applies axial pressure to the body (2) of the rotor (1), and the rotor (1), the wire guide cap (20) and the vice (22) rotate together, i.e., synchronously, around the axis of approach (Y); - once winding is complete, the rotor (1) is kept stationary while the wire guide caps (20) are removed from the pole pieces (4), i.e. disengaged from the rotor (1), and the vice (22) is released and disengaged from the rotor (1).

7. 10. A method according to any one of the preceding claims, characterized in that the axial pressure is applied to the body (2) of the rotor (1) at the edges of the pole pieces (4).

8. 10. A method according to any one of the preceding claims, characterized in that the operation of the wire guide cap (20) depends on the activation or deactivation of the pressing device (22).

9. 10. The method according to any one of the preceding claims, characterized in that the axial pressure exerted by the pressing device (22) on the body (2) of the rotor (1) is adjustable.

10. An in-slot winding machine (14) for forming windings of conductive wire (8) on pole pieces (4) of a rotor (1) of an electric motor, comprising: a main shaft or support (15) provided with means (19, 21) for supporting the body (2) of the rotor (1); a tailstock (16) movable along an approach axis (Y) relative to the main shaft (15) between a proximal position in engagement with the body (2) of the rotor (1) supported on the main shaft (15) and a distal position in disengagement from the body (2) of the rotor (1); a unit (17) for supplying said conductive wire (8), In the winding machine (14), the tailstock (16) includes a wire guide cap (20) movable relative to the main shaft (15), and the wire guide cap (20) is movable between a position where the insertion width of the wire guide cap (20) into the rotor slot (5) of the body (2) of the rotor (1) supported by the main shaft (15) is maximum, and a position where the wire guide cap (20) is not engaged with the rotor slot (5), where the insertion width is minimum, or where the wire guide cap (20) is disengaged. A winding machine (14) comprising a pressing device (22) arranged inside the wire guide cap (20) and configured to press the body (2) of the rotor (1) in the axial direction.

11. 11. The winding machine (14) according to claim 10, characterized in that the pressing device (22) is capable of adjusting a calibrated axial pressure applied to the body (2) of the rotor (1) parallel to the rotation axis (Z) of the rotor (1), in particular to a pressure sufficient to compress the body (2) against the elasticity of the body (2) and minimize its height.

12. 12. The winding machine (14) according to claim 10 or claim 11, characterized in that the pressing device (22) is operable throughout the entire winding.

13. A winding machine (14) according to any one of the preceding claims, which in use comprises: - the body (2) of the rotor (1) is kept stationary in the main shaft or support (15), while the wire guide cap (20) is moved alternately in both directions in the rotor slot (5) along the approach axis (Y), and the conductive wire (8) is wound onto the wire guide cap (8) by a feeding unit (17), thereby laying it on the pole pieces (4); - the wire guide cap (20) moves alternately in both directions along an approach axis (Y) in the rotor slot (5), and the main shaft (15), the body (2) of the rotor (1), the wire guide cap (20), and the pressing device (22) integrated in the wire guide cap (20) are rotated simultaneously and integrally around the approach axis (Y).

14. 14. A winding machine (14) according to claim 13, characterized in that the body (2) of the rotor (1) is supported on the main shaft or support (15) so that the rotation axis (Z) of the rotor (1) is perpendicular to and intersects with the approach axis (Y), the wire guide cap (20) is capable of controlled displacement in both directions along the approach axis (Y), the wire guide cap (20) has a size that substantially surrounds the pole pieces (4) of the rotor (1), and the pressing device (22) is a vice integrated in the wire guide cap (20).

15. 15. The winding machine (14) according to claim 14, wherein the main shaft (15), the main body (2) of the rotor (1), the wire guide cap (20), and the vise (22) integrated in the wire guide cap (20) are rotatable together on the approach axis (Y).

16. 16. The winding machine (14) according to claim 15, characterized in that the rotation of the wire guide cap (20) and the vise (22) about the axis of approach (Y) depends on the action of the vise (22) on the edge of at least one pole piece (4) of the body (2) of the rotor (1).

17. 10. A winding machine (14) according to any one of the preceding claims, characterized in that the pressing device (22) comprises a vise having two jaws (23, 24), the two jaws (23, 24) being radially movable relative to the approximation axis (Y) between a distal position corresponding to an open state of the vise (22) and a proximal position corresponding to a closed state of the vise (22).

18. 18. The winding machine (14) of claim 17, further comprising an actuator for the vise (22), the actuator comprising a drive shaft (25) extending on the approximation axis (Y), a lever system (27) fixed to the jaws (23, 24), and at least one spring for continuously applying a return force returning the jaws (23, 24) to a closed position proximal to the vise (22), The drive shaft (25) slides along the approximation axis (Y) between an engaged position of the lever system (27), in which the lever system (27) resists the action of the spring to maintain the jaws (23, 24) in a distal open position of the vise (22), and a disengaged position of the lever system (27), in which the lever system (27) does not resist the action of the spring and the jaws (23, 24) are in a proximal closed position of the vise (22).

19. 19. The winding machine (14) according to claim 18, characterized in that the wire guide cap (20) is mounted on a rotating shaft (28) rotatable about the axis of approach (Y), and the drive shaft (25) of the vise (22) is coaxially arranged inside the rotating shaft (28) of the wire guide cap (20).

20. 10. The winding machine (14) according to claim 9, wherein the wire guide cap (20) comprises two halves (20′, 20″) arranged on opposite sides of the pressing device (22) and movable radially toward and away from each other relative to the approach axis (Y) to change the size of the wire guide cap (20).

21. 10. A winding machine (14) according to claim 9, wherein the wire guide cap (20) is movable along the approach axis (Y) relative to the pressing device (22) for insertion into the rotor slot (5) when the pressing device (22) is engaged with the body (2) of the rotor (1).

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