Method for producing a wound magnetic rotor of a rotary electric machine

Abstract

The invention relates to a method for producing a rotor of a rotary electric machine rotating about an axis of rotation (12), the rotor comprising a magnetic core (10) and a plurality of windings of electrical conductors that each form a coil surrounding one portion of the magnetic core, wherein the magnetic core extends between two radial faces and includes core slots extending longitudinally parallel to the axis of rotation, wherein each coil is formed of pins having one or two branches inserted into the slots and ending in a free end, and rigid conductors connecting two of the branches, wherein the rigid conductors extend mainly parallel to the radial faces, and wherein each branch is connected to one of the rigid conductors substantially in the longitudinal extension of the corresponding slot, by alternating the placement of a series of branches and a level of rigid conductors.

Description

DESCRIPTION Method for producing a wound magnetic rotor for a rotating electrical machine

[0001] The invention relates to a method for producing a wound magnetic rotor for a rotating electrical machine. An electric machine is understood to mean a rotating machine capable of converting electrical energy into mechanical energy and acting as a motor or capable of producing electrical energy from mechanical energy and acting as a generator. The same machine can be defined to alternate phases where it acts as a motor and a generator.

[0002] An electrical machine consists of a fixed part called a stator and a moving part called a rotor. Wound rotors generally include a magnetic core and coils of electrical conductors to define magnetic poles facing the poles of the stator of the electrical machine. The rotor can rotate in one direction or possibly in both directions.

[0003] It is possible to make the coils of electrical conductors outside their magnetic core and then insert the already shaped coils into notches in the magnetic core designed to receive them. The coils are inserted radially relative to the rotor's rotation axis. This type of production is not easily automated.

[0004] Alternatively, the coils can be made from pins inserted axially into the slots of the magnetic core. Making coils from pins is well suited to making assemblies with smooth poles but can also be implemented for assemblies with salient poles. In the case of coils made from pins, after insertion, the pins are connected together to form the turns of the coil. To make these turns, the free ends of the pin arms are connected together, for example by soldering. Before making the connection of the free ends, it is necessary to shape the arms in a part opening out of the slots in order to bring them together to be able to make the connection.

[0005] This operation of shaping the arms in order to bring them together to connect them is tedious and can be subject to error due to the large number of pins forming a single coil.

[0006] The invention aims to propose a new method for manufacturing wound magnetic rotors in which the coils are directly produced on the magnetic core comprising longitudinal notches intended to receive pins connected together by means of rigid electrical conductors whose shape is defined so that the connections of the pins and the conductors can be made in the extension of the notches.

[0007] This manufacturing process simplifies the assembly of a wound magnetic rotor. In addition to simplifying rotor assembly, these connections between pins and specific rigid conductors improve the reproducibility and traceability of the wound magnetic component. More specifically, the specific connections are spatially distributed in a more controlled manner.

[0008] To this end, the invention relates to a method for producing a wound rotor of an electrical machine rotating around an axis of rotation, the rotor comprising a magnetic core and several windings of electrical conductors each forming a coil surrounding a part of the magnetic core, the magnetic core extending between two radial faces and in which are made notches extending longitudinally parallel to the axis of rotation, each coil being formed of pins each having one or two branches inserted in series in the notches and ending in a free end and of rigid conductors distributed by levels and each electrically connecting two of the branches, the rigid conductors extending mainly parallel to the radial faces, the electrical connection of each branch to one of the rigid conductors being made substantially in the longitudinal extension of the corresponding notch,the process chaining the following steps:, 1. Arrange a level of rank M of rigid conductors along the first of the two radial faces, 2. Insert a series of rank N branches into the notches, the free ends of these branches emerging from the notches beyond the level of rank M of rigid conductors, 3. Prepare the electrical connection of a first part of the free ends of the series rank N of branches to rigid conductors of the level of rank M, 4. Arrange a level of rank M+1 of rigid conductors covering the level of rank M of rigid conductors, 5. Prepare the electrical connection of a second part of the free ends of the series of rank N branches to rigid conductors of the level of rank M+1, Steps 2 to 5 are then repeated by incrementing the rank of the branch series and the rank of the rigid conductor levels.

[0009] It is possible to perform between step 3 and step 4: - the electrical connection of the first part of the free ends of the series rank N of branches to the rigid conductors of the level of rank M and, - the electrical connection of the second part of the free ends of the series rank N-1 of branches to the rigid conductors of the level of rank M, if applicable.

[0010] Alternatively: - between step 3 and step 4, the electrical connection of the first part of the free ends of the series rank N of branches to the rigid conductors of the level of rank M is carried out and, - after step 5, the electrical connection of the second part of the free ends of the series of rank N branches to the rigid conductors of the level of rank M+1 is carried out.

[0011] Advantageously, rigid conductors of the same level do not cross.

[0012] Advantageously, the rigid conductors of the same level are attached to an insulating substrate extending mainly in the radial plane.

[0013] Advantageously, each substrate comprises axial protrusions arranged between the rigid conductors and configured to extend axially beyond the free ends of the branches after electrical connection of the branches to the rigid conductors.

[0014] Advantageously, the preparation of the electrical connection of the different free ends includes an operation of bending each free end to come into contact with the corresponding rigid conductor.

[0015] Advantageously, each substrate comprises counterforms on each of which one of the free ends rests during the folding operation.

[0016] Advantageously, the section of a conductive wire used to make the pins is substantially the same as the section of a conductive wire used to make the rigid conductors.

[0017] Advantageously, the pins and rigid conductors are made from flat wires.

[0018] Advantageously, the electrical connection of the rigid conductors to the free ends of the different branches is carried out by brazing.

[0019] Advantageously, to achieve the connection of one of the branches to one of the rigid conductors, the free end of the branch considered is folded to come into contact with the rigid conductor considered defining a contact surface and in which the length of the periphery of the contact surface is greater than the length of a section of the branch considered, the section being defined parallel to the radial plane.

[0020] The invention will be better understood and other advantages will appear on reading the detailed description of an embodiment given by way of example, a description illustrated by the attached drawing in which:

[0021] Figure 1 shows a magnetic core of a wound rotor;

[0022] Figure 2 partially represents the magnetic core, several pins intended to be inserted into notches in the magnetic core of Figure 1, as well as rigid conductors for electrically connecting the pins together;

[0023] Figure 3 illustrates the electrical connection of pins belonging to different radial series;

[0024] Figure 4 represents a substrate carrying rigid conductors allowing the electrical connection of the pins;

[0025] Figures 5, 6 and 7 illustrate several variants of a method of connecting a branch to one of the conductors;

[0026] Figure 8 represents an example of a sequence of steps of the method of the invention;

[0027] Figure 9 shows a variant of the magnetic core, two pins and a rigid conductor for connecting the two pins;

[0028] Figure 10 shows different pins connected to the substrate of Figure 4,

[0029] Figure 11 shows a stack of several substrates on a magnetic core.

[0030] For the sake of clarity, the same elements will have the same references in the different figures.

[0031] Figure 1 represents a magnetic core 10 of a rotor according to the invention and equipping an electrical machine. The magnetic core is made of ferromagnetic material and has the overall shape of a portion of a cylinder with a circular section around an axis 12. The rotor is then intended to rotate around the axis 12 inside a stator of the electrical machine. Figure 1 represents a magnetic core of an internal rotor, i.e. capable of rotating inside a stator. It is also possible to implement the invention for an external rotor, i.e. rotating around the stator.

[0032] The magnetic core 10 is configured to define several magnetic poles alternating radially to the cylindrical surface of the magnetic core 10. In the example shown in Figure 1, the magnetic core 10 is configured to form four magnetic poles 14, 15, 16 and 17 arranged at 90° to each other around the axis 12. It is of course possible to implement the invention for any other number of poles, generally equally distributed. radially around the axis 12. Each pole comprises a coil formed of an electrical conductor wound around a solid part of the magnetic core. The electrical conductor is arranged in notches made in the magnetic core 10. The notches have the form of longitudinal grooves extending parallel to the axis 12. In Figure 1, eight notches appear between each pole. The notches closest to pole 14 are marked 141, 142, 143, 144, 145, 146, 147 and 148. The marked notches are divided into two groups, one group on each side of pole 14. In Figure 1, the notches of the first group 141, 142, 143, 144 are visible to the right of pole 14 and the notches of the second group 145, 146, 147, 148 are to the left of pole 14. The electrical conductor forming a coil surrounding pole 14 is wound in the notches 141 to 148.In the same way around each of the poles 15, 16 and 17, an electrical conductor is wound in the notches closest to the corresponding poles to form the coils of each pole.

[0033] The magnetic core 10 extends between two radial faces 21 and 22.

[0034] Each coil is made by means of pins, visible in Figure 2, inserted into the notches associated with the corresponding pole by the radial face 21. In Figure 2, we can see the pole 14 and the notches 141, 142, 145 and 146 belonging to the magnetic core 10.

[0035] After their insertion, the pins are electrically connected to each other at the level of the radial face 22 of the magnetic core 10 by means of rigid conductors arranged along the radial face 22. To produce a coil, several layers of pins are placed in the same notch.

[0036] The rigid conductors extend mainly parallel to the radial faces 21 and 22. In other words, for each rigid conductor, it is possible to define a minimal parallelepiped volume containing it. The smallest dimension of this volume is perpendicular to the radial faces 21 and 22.

[0037] It is possible to insert a pin with only one branch into one of the notches, used for example for the electrical connection of the coil. The power supply of the individual coils can be achieved in different ways. The external connection of the coils is not shown and does not form the subject of the present invention which concerns the internal connection to a coil.

[0038] The number of turns in each coil can vary depending on the rotor and stator definition. The number of turns can be adapted by varying the number of slots per group and the number of layers of pins inserted in each slot. In practice, the pins are made using insulated electrical wires, for example enameled. The cross-section of the wires can be of any shape, including circular or rectangular. A rectangular cross-section allows for better filling of the slots. More precisely, in the example shown, the length of the rectangular cross-section of a pin is close to the width of the slots, excluding the functional clearance to allow the insertion of the pins. As mentioned above, wires with a rectangular cross-section are called flat wires.

[0039] Figure 2 shows several pins and more precisely a pin 31 in a complete manner and the pins 32 and 33 in a partial manner. The pins 31, 32 and 33 belong to a coil surrounding the magnetic pole 14. In Figure 2 appears the radial face 22 of the magnetic core 10. The pin 31 comprises two branches 311 and 312. The branch 311 is inserted into the notch 142 and the branch 312 into the notch 145. The branch 321 of the pin 32 is inserted into the notch 141 and the branch 332 of the pin 33 is inserted into the notch 146. The branches of the different pins are arranged parallel to the axis 12.

[0040] The pins can be inserted through the radial face 21 of the magnetic core 10, a face not appearing in FIG. 2. The branches can be inserted by translation parallel or perpendicular to the axis 12, in particular for pins having only one branch, in the corresponding notches. After insertion, a free end of each branch protrudes from the radial face 22. The free ends are used for the electrical connection of the pins together in order to produce the coil arranged around the magnetic pole 14.

[0041] The electrical connection of the different coils can be made by free ends of branches, on the side of the radial face 22 by means of pins with two branches or on the side of the radial face 21 by means of single-branch pins.

[0042] To make the connection of the branches, rigid electrical conductors are arranged along the radial face 22. A rigid conductor connects two branches of two separate pins in order to make a winding around the pole 14. In the example shown, a rigid conductor 41 connects the branches 311 and 332. A rigid conductor 42 connects the branches 312 and 321. Generally, to make a coil, the connection of a branch to the rigid conductor is made substantially in the longitudinal extension of the notch in which the branch has been inserted. The extension of the notch is defined parallel to the axis 12. Consequently, each rigid conductor extends substantially between longitudinal projections of the notches receiving the branches connected by the rigid conductor concerned. The presence of rigid conductors separate from the pins makes it possible to avoid direct connection between free ends of branches.This type of direct connection requires complex bending of the branches as well as crossings between branches which the invention makes it possible to avoid.

[0043] In order to facilitate the arrangement of the rigid conductors 41 and 42, they can both advantageously extend in the same radial plane 23 parallel to the radial face 22. In this arrangement, the rigid conductors 41 and 42 do not cross. This makes it easier to produce the conductor level shown in Figure 2. It is of course possible to arrange more than two rigid conductors in the same plane. In Figure 2, the rigid conductors 41 and 42 surround the magnetic pole 14. In the same plane, it is possible to arrange rigid conductors surrounding other poles or even all the magnetic poles of the core 10.

[0044] The branches shown in Figure 2 may belong to the same layer or to neighboring layers in the arrangement of the pins in their respective notches. The rigid conductors 41 and 42 shown in Figure 2 belong to a level 40 of conductors. To ensure the connection of the different branches, several levels of rigid conductors are present. Each level extends in a plane 23 of its own. This makes it possible to facilitate the making of connections between the branches and the corresponding rigid conductors.

[0045] In each slot several branches are inserted. Figure 3 illustrates how different layers of branches, inserted in the same slot, can be connected by means of rigid conductors to form a coil. As in Figure 2, Figure 3 shows a slot 145 formed in the magnetic core 10. The placement of several layers of branches and their connection can also be implemented for other slots in the magnetic core of a rotor.

[0046] In Figure 3, the radial face 22 of the magnetic core 10 is shown partially around the notch 145. The branch 341 of the pin 34 and the branch 351 of the pin 35 are both inserted into the notch 145. The branch 341 belonging to the layer 48 is located closer to the axis 12 than the branch 351 belonging to the layer 58. A rigid conductor 43 belonging to the level 40 connects the branches 341 and 352. Another rigid conductor 51, shown partially and belonging to the level 50, is connected to the branch 351. The rigid conductors 43 and 51 are stacked by level parallel to the radial face 22, each of the levels in a plane 23 which is specific to it.

[0047] The rigid conductors can be directly connected to the branches of the pins and the connection can be sufficient to hold the rigid conductors in position. Figure 4 represents an advantageous variant in which the rigid conductors of the same level are integral with an insulating substrate 24 extending mainly in the radial plane 23. In Figure 4, there are rigid conductors 61 to 64 surrounding one of the magnetic poles and a conductor 65 intended to surround another magnetic pole. A branch 361 is connected to the rigid conductor 65. The branches connected to the conductors 61 to 64 are not shown. Figure 4 only partially represents the substrate 24 and the rigid conductors that it carries. The substrate 24 can have a washer shape extending mainly in the plane 23 and surrounding the axis 12 of the rotor.Rigid conductors carried by the same substrate allow pins belonging to one or more poles to be connected. magnetic. Advantageously, rigid conductors carried by the same substrate allow pins belonging to all the magnetic poles of the rotor to be connected. The rigid conductors carried by the same substrate form a level 60 of conductors.

[0048] Rigid conductors can be made in different ways, such as by plastic deformation of a conductive wire, for example, delivered in a roll, just like pins. Advantageously, the cross-section of the conductive wire used to make the pins is substantially the same as the cross-section of the conductive wire used to make the rigid conductors. By substantially the same cross-section, we mean that the nominal dimensions of the cross-sections of the conductive wires used on the one hand for the rigid conductors and on the other hand for the pins are the same. Dimensional deviations may occur within the tolerances given by the conductor manufacturers and also depending on the shaping of the conductors. This same cross-section makes it possible to avoid changes in the cross-section of the electrical conductor in the coil. This conductive wire may in particular be a flat conductive wire.The rigid conductor can also be manufactured by additive or subtractive manufacturing of an electrically conductive material, particularly copper-based. The substrate can be produced, in particular, by additive or subtractive manufacturing, by molding an electrically insulating material.

[0049] The substrate 24 may comprise axial protrusions 241 arranged between the rigid conductors. The axial protrusions 241 are configured to extend axially, that is to say parallel to the axis 12, beyond the free ends of the branches after electrical connection of the branches to the rigid conductors. For a given level of rigid conductors, the axial protrusions 241 form spacers on which the substrate 24 of the next level of rigid conductors rests without the free ends of the branches connected to the given level of rigid conductors coming into contact with the substrate 24 of the next level of rigid conductors. In other words, a positive functional clearance remains between the free ends of the branches and the substrate 24 of the next level. This makes it possible to maintain, in an axial direction, a significant manufacturing tolerance of the electrical connections of the branches on the rigid conductors without this tolerance does not harm the installation of the different levels of rigid conductors whose substrates 24 are in contact with each other.

[0050] The various rigid conductors may be thinned at the connection with the corresponding free ends of the branches in order to reduce the axial protrusion of the electrical connections of the branches on their respective rigid conductor. In Figure 4, depressions forming thinned areas can be seen. For example, on the rigid conductor 64, a depression 641 is formed. The other rigid conductors include the same depressions not referenced so as not to weigh down Figure 4. The shape of the rigid conductors, and in particular the depressions, can be obtained by different manufacturing processes, machining, plastic deformation, additive manufacturing, etc.

[0051] Figure 5 illustrates a method of connecting a branch to a rigid conductor. Branch 361 is inserted into a notch of the magnetic core 10. Figure 5 is a partial representation in a radial plane of the rotor containing the notch into which branch 361 is inserted. In Figure 5, other branches, 351, 341 and 331 are partially shown. Branches 361, 351, 341 and 331 are all inserted into the same notch. In other words, the branches appearing in Figure 5 belong to different layers.

[0052] After insertion of the pins into their respective notches, the rigid conductors, possibly secured to their substrate 24, are positioned along the face 22 of the magnetic core 10. The branch 361 has a free end 361a which can be folded after insertion into the notch. The free end 361a is prepared for a connection. More precisely, the electrical insulation of the branch 361 is removed at the free end 361a. This preparation of the free end 361a can take place before or after insertion of the branch 361 into the corresponding notch. The free end 361a is folded to come into contact with the conductor 65, which has also been prepared. Once the free end 361a is in contact with the conductor 65, the connection is made. This may be a brazing 25 as shown in Figure 5. A tool 27 may ensure the bending and hold the free end 361 a at the contact of conductor 65 during the soldering operation. Any other means of connection can be used, such as crimping.

[0053] The tool 27 can, by itself, hold each free end during folding. Alternatively, to facilitate folding and simplify the tool 27, each substrate 24 can comprise counterforms 242, visible in FIG. 4. Each counterform 242 is configured so that, during folding, one of the free ends rests on it.

[0054] Figures 6 and 7 show variants suitable for brazing with bending as shown in Figure 5. In the variant shown in Figure 6, the free end 361 b of the branch 361 comprises a notch 361 c configured to increase the length of the periphery 361 d of the contact surface 361 e between the free end 361 b and the rigid conductor 65. Thus, during brazing, the length of the brazing bead is greater than the length of the brazing bead obtained without a notch. The brazing bead follows the periphery 361 d. The periphery 361 d and therefore the brazing bead are shown in bold lines in Figure 6. By increasing this length, the mechanical strength of the brazing is improved. This advantage is of particular interest for a rotor in order to improve its mechanical strength and in particular its resistance to centrifugal forces due to the rotation of the rotor.

[0055] In the variant shown in Figure 7, the free end 361 f of the branch 361 comprises a bore 361 g which, as in the variant shown in Figure 6, is configured to increase the length of the periphery 361 d of the contact surface 361 e between the free end 361 f and the rigid conductor 65. Indeed, the contour of the bore contributes to the periphery. It is possible to combine one or more accidents of external shapes such as the notch 361 c of the variant of Figure 6 and one or more accidents of internal shapes such as the bore 361 g of the variant of Figure 7. More generally, any shape of free end making it possible to increase the length of the periphery of the contact surface between the free end and the rigid conductor is advantageous.

[0056] Alternatively, to the folding illustrated in Figures 5 to 7, it is possible to keep the free ends of the pins without folding, for example by providing holes in the rigid conductors, holes crossed by the free ends. The free ends of the pins are placed in the holes of the rigid conductors by translating the rigid conductors along the axis 12. After placement, it is easy to connect the free ends to their respective rigid conductor, for example by soldering, in the manner of an electronic component to be inserted into a printed circuit. However, folding the free ends has several advantages and in particular the fact of better controlling the axial protrusion of the free ends of the branches after their connection to the respective rigid conductors.

[0057] The sequence of steps of inserting the branches into the notches, placing levels of rigid conductors and connecting the branches to the rigid conductors is repeated by alternating a series of branches and a level of rigid conductors. A series of branches includes several branches belonging to the same layer or to neighboring layers.

[0058] Figure 8 illustrates an example of a sequence of steps of the method of the invention. A rank of the series of branches and a rank of the levels of rigid conductors are defined. To better understand the invention, the sequence of steps can be described for a current rank M of rigid conductors and a current rank N of series of branches.

[0059] In a first step, a level of rank M of rigid conductors is placed along the face 22. This level is for example level 40 shown in figure 3.

[0060] In a second step, a series of rank N branches is inserted into the notches, the free ends of these branches opening out of the notches, along axis 12, beyond the level of rank M of rigid conductors. In Figure 8, we can see 8 branches arranged between two poles. Figure 8 illustrates the sequence of steps between two magnetic poles. In Figure 8, we can see 8 branches per series. When the rigid conductors are carried by the same substrate going around axis 12, the series of branches considered includes branches arranged between all the magnetic poles of the rotor.

[0061] For the first level of rigid conductors and for the first series of branches, the first two steps can be reversed.

[0062] Then, in a third step, the electrical connection of a first part of the free ends of the series of branches of rank N to rigid conductors of level M is prepared. In the example shown in Figure 8, four free ends of branches are folded to come into contact with their respective rigid conductor. As seen previously, other methods of preparation are possible. The other four branches of the series of rank N are not folded. The preparation of their electrical connection will take place later in the fifth step.

[0063] Then, in a fourth step, a level of rank M+1 of rigid conductors is placed covering the level of rank M of rigid conductors. This is, for example, level 50 of rigid conductors shown in Figure 3. Level 50 covers level 40, which was installed in step 1.

[0064] Then, in a fifth step, the electrical connection of a second part of the free ends of the series of rank N branches to rigid conductors of the level of rank M+1 is prepared.

[0065] Then, steps 2 to 5 are repeated by incrementing the ranks of the branch series and the ranks of the rigid conductor levels.

[0066] The electrical connection, for example by soldering, of the free ends of the branches to their respective rigid conductor can take place after each connection preparation step, i.e. between step 3 and step 4 as well as between step 5 and step 2 of the higher rows of branch series and level of rigid conductors. In other words, the preparation and electrical connection steps are not distinguished.

[0067] Alternatively, to reduce the number of electrical connection steps, it is possible to carry out between step 3 and step 4 both the electrical connection of the first part of the free ends of the series rank N of branches to the rigid conductors of the level of rank M and the electrical connection of the second part of the free ends of the series rank N-1 of branches to the rigid conductors of the level of rank M. Thus, there is only one single electrical connection step per level of rigid conductors and we avoid an electrical connection step after step 5.

[0068] In the examples shown in Figures 2, 3 and 4, the free ends of the branches are folded towards the axis 12. As mentioned above, it is also possible to fold the free ends of the branches away from the axis 12. Figure 5 illustrates such a folding which can be described as radial.

[0069] Figure 9 represents a variant of connection of two pins 37 and 38 and more precisely of their respective branches 371 and 382 by means of a rigid conductor 44 extending on its substrate 24 parallel to the face 22 of the magnetic core 10. In the variant of Figure 9, the folding is carried out perpendicular to a radial direction. In the example shown in Figure 9, the conductive wires used to make the pins are flat wires. The folding can be carried out on the flat of the wire or on its edge.

[0070] Figure 10 shows the substrate 24 carrying the rigid conductors 61 to 64 as well as several pins intended to be connected to the rigid conductors carried by this substrate or to other rigid conductors. It can be seen in Figure 10 that the rigid conductors are arranged closer to the axis 12 than the pins whose branches are shown. Alternatively, the rigid conductors can be arranged further from the axis 12 than the pins. Both arrangements are conceivable within the scope of the invention. The arrangement shown is advantageous for an internal rotor because the rigid conductors do not leave the radial volume of the rotor.

[0071] It is desirable to provide means for positioning the different substrates 24 relative to each other. In Figure 10, the substrate 24 is equipped with a radial protrusion 26 projecting from the area occupied by the rigid conductors and making it possible to ensure the positioning and holding of the different substrates 24. The protrusions 26 of several superimposed substrates 24 are for example pierced with holes arranged opposite each other in order to slide a rod therein holding the substrates together. The rod can also be inserted into a hole in the magnetic core made opposite the holes in the substrates 24, which makes it possible to ensure the positioning and holding of the different substrates 24 between them and relative to the magnetic core. Any other means of positioning and holding is of course possible. Holding can for example be ensured by means of an external hoop.

[0072] Figure 11 represents a magnetic core 10 comprising a stack of several substrates 24. For the pole 14, a substrate 24 makes it possible to connect eight branches, four branches on each side of the pole 14. As mentioned above, the invention can be implemented regardless of the number of branches arranged on each side of the pole 14. The number of branches and the number of layers are notably defined as a function of the number of turns that the coil must comprise and the spatial organization of these turns around the pole 14. A substrate 24 allows the same connections for the other poles of the rotor. Without considering the protrusions 26, the substrates 24 can have external diameters that increase as the substrates 24 move away from the magnetic core 10. In Figure 11, the protrusions of the different substrates 24 are aligned to facilitate the fixing of the different substrates.

[0073] Figures 9 and 10 are well suited to the construction of a rotor for which the magnetic poles are spatially defined. The protrusions are advantageously arranged in the longitudinal extension of the magnetic poles. Alternatively, protrusions, allowing the positioning and holding of the substrates, yet the rigid conductors, can be arranged outside the longitudinal extensions of the magnetic poles.

Claims

CLAIMS 1 . Method for producing a wound rotor of an electrical machine rotating around an axis of rotation (12), the rotor comprising a magnetic core (10) and several windings of electrical conductors each forming a coil surrounding a part of the magnetic core, the magnetic core (10) extending between two radial faces (21, 22) and in which are made notches (141, 142, 143, 144, 145, 146, 147, 148) extending longitudinally parallel to the axis of rotation, each coil being formed of pins (31, 32, 33, 34, 35, 36, 37, 38) each having one or two branches (311, 312, 321, 332, 341, 351, 352, 371, 382) inserted in series into the notches and ending in a free end (361 a) and rigid conductors (41, 42, 43, 44, 51, 61, 62, 63, 64) distributed by levels and each electrically connecting two of the branches, the rigid conductors extending mainly parallel to the radial faces,the electrical connection of each branch to one of the rigid conductors being made substantially in the longitudinal extension of the corresponding notch, the method chaining the following steps:, 1. Arrange a level of rank M of rigid conductors along the first (22) of the two radial faces, 2. Insert a series of rank N branches into the notches, the free ends of these branches emerging from the notches beyond the level of rank M of rigid conductors, 3. Prepare the electrical connection of a first part of the free ends of the series rank N of branches to rigid conductors of the level of rank M, 4. Arrange a level of rank M+1 of rigid conductors covering the level of rank M of rigid conductors, 5. Prepare the electrical connection of a second part of the free ends of the series of rank N branches to rigid conductors of the level of rank M+1, Steps 2 to 5 are then repeated by incrementing the rank of the branch series and the rank of the rigid conductor levels.

2. Method according to claim 1, in which between step 3 and step 4, the following are carried out: - the electrical connection of the first part of the free ends of the series rank N of branches to the rigid conductors of the level of rank M and, - the electrical connection of the second part of the free ends of the series rank N-1 of branches to the rigid conductors of the level of rank M, if applicable.

3. Method according to claim 1, in which: - between step 3 and step 4, the electrical connection of the first part of the free ends of the series rank N of branches to the rigid conductors of the level of rank M and, - after step 5, the electrical connection of the second part of the free ends of the series of rank N branches to the rigid conductors of the level of rank M+1 is carried out.

4. Method according to one of the preceding claims, in which the rigid conductors of the same level do not cross.

5. Method according to one of the preceding claims, in which the rigid conductors of the same level are attached to an insulating substrate (24) extending mainly in the radial plane (23).

6. The method of claim 5, wherein each substrate (24) comprises axial protrusions (241) disposed between the rigid conductors and configured to extend axially beyond the free ends of the branches after electrical connection of the branches to the rigid conductors.

7. Method according to one of claims 5 or 6, in which the preparation of the electrical connection of the different free ends comprises an operation of bending each free end to come into contact with the corresponding rigid conductor.

8. Method according to claim 7, in which each substrate (24) comprises counterforms (242) on each of which one of the free ends rests during the folding operation.

9. Method according to one of the preceding claims, in which the section of a conductive wire used to make the pins is substantially the same as the section of a conductive wire used to make the rigid conductors.

10. Method according to one of the preceding claims, in which the pins and the rigid conductors are made from flat wires.

11. Method according to one of the preceding claims, in which the connection of the rigid conductors to the free ends of the different branches is carried out by soldering.

12. Method according to the preceding claim, in which, to carry out the connection of one of the branches to one of the rigid conductors, the free end of the branch considered is folded to come into contact with the rigid conductor considered defining a contact surface and in which the length of the periphery of the contact surface is greater than the length of a section of the branch considered, the section being defined parallel to the radial plane (23).

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