Method for manufacturing a wound magnetic rotor of a rotating electrical machine

Abstract

The invention relates to a method for manufacturing a rotor of a rotary electrical machine about a rotation axis (12), said rotor comprising a magnetic core (10) and a plurality of windings of electrical conductors, each winding forming a coil about a portion of said magnetic core, the magnetic core extending between two radial surfaces and having formed therein slots extending longitudinally parallel to said rotation axis, each coil being formed by hairpins, each hairpin having one or two branches inserted into said slots and ending in a free end, and rigid conductors, each rigid conductor connecting two of said branches, the rigid conductors extending mainly parallel to said radial surfaces, the connection of each branch to one of said rigid conductors being substantially achieved in the longitudinal extension of the corresponding slot, the series of branches and the levels of rigid conductors being installed alternately.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a wound magnetic rotor for a rotating electric machine. An electric machine is a rotating machine that can convert electrical energy into mechanical energy for use as an electric motor, or can generate electrical energy from mechanical energy for use as a generator. A single machine can be defined as alternating between being used as an electric motor and as a generator. Background Technology

[0002] An electrical machine consists of a stationary part called the stator and a movable part called the rotor. A wound rotor typically includes a magnetic core and coils of electrical conductors that define magnetic poles facing the poles of the stator of the machine. The rotor can rotate in one direction or optionally in two directions.

[0003] Electrical conductor coils can be fabricated and shaped outside their magnetic core, and then inserted into slots in the core designed to receive them. The coils are inserted radially relative to the rotor's axis of rotation. This type of production is not easily automated.

[0004] Alternatively, the coil can be made from hairpins that are axially inserted into slots in the magnetic core. Coils made from hairpins are well-suited for manufacturing salient pole components, but can also be used for salient pole components. In the case of coils made from hairpins, after insertion, the hairpins are joined together to form turns of the coil. To produce these turns, the free ends of the hairpin legs are joined together, for example, by brazing. Before joining the free ends, a portion of the legs extending from the slot must be shaped to bring them closer together to achieve the connection.

[0005] Because of the large number of hairpins that form a single coil, the operation of shaping the branches to bring them closer together for connection is laborious and error-prone. Summary of the Invention

[0006] The present invention aims to provide a novel method for manufacturing a wound magnetic rotor, wherein the coil is formed directly on a magnetic core including longitudinal slots designed to receive hairpins connected to each other by rigid electrical conductors, the rigid electrical conductors being shaped such that the hairpins and conductors can be formed in extensions of the slots.

[0007] This manufacturing process simplifies the assembly of wound magnetic rotors. In addition to simplifying rotor assembly, these connections between the hairpin and specific rigid conductors improve the repeatability and traceability of the wound magnetic components. More specifically, the spatial distribution of these specific connections is better controlled.

[0008] Therefore, the present invention relates to a method for manufacturing a wound rotor around a rotation axis for a rotary electrical machine, the rotor comprising a magnetic core and a plurality of electrical conductor windings, each winding forming a coil around a portion of the magnetic core. The magnetic core extends between two radial end faces, and a slot is formed therein that extends longitudinally parallel to the axis of rotation. Each coil is formed by a hairpin, each hairpin having one or two branches inserted in series into a slot and terminating at a free end, and rigid conductors distributed in layers and each electrically connecting two of the branches. The rigid conductors extend primarily parallel to the radial end face, and the electrical connection of each branch to one of the rigid conductors is substantially achieved in the longitudinal extension of the corresponding slot. The method includes the following steps: 1. Arrange M-level rigid conductors along the first of the two radial end faces. 2. A series of N-level branches are inserted into the slot, with the free ends of these branches extending beyond the M-level rigid conductor. 3. Prepare to electrically connect the first portion of the free ends of a series of N-level branches to the M-level rigid conductor. 4. Arrange rigid conductors of level M+1 to overlap with rigid conductors of level M. 5. Prepare to electrically connect the second part of the free ends of a series of N-level branches to the rigid conductor of the M+1 level. Then repeat steps 2 through 5, increasing the branch series level and the rigid conductor layer level.

[0009] The following operations can be performed between step 3 and step 4: - Electrically connecting the first portion of the free ends of a series of N-level branches to a rigid conductor of the M-level layer; and - Electrically connect the second part of the free end of a series of N-1 level branches to the rigid conductor of the M level, if applicable.

[0010] Alternatively: - Between steps 3 and 4, the first portion of the free ends of a series of N-level branches is electrically connected to the rigid conductor of the M-level layer; and - After step 5, the second part of the free ends of a series of N-level branches is electrically connected to the rigid conductor of the M+1 level.

[0011] Advantageously, rigid conductors at a given level do not cross.

[0012] Advantageously, a rigid conductor of a given level is attached to an insulating substrate that extends primarily in a radial plane.

[0013] Advantageously, each substrate includes axial protrusions arranged between the rigid conductors and configured to extend axially beyond the free end of the branch after the branch is electrically connected to the rigid conductor.

[0014] Advantageously, the preparation of the electrical connection at each free end includes bending each free end to make contact with the corresponding rigid conductor.

[0015] Advantageously, each base includes a mating portion, during which one of the free ends abuts against each mating portion.

[0016] Advantageously, the cross-section of the conductive wire used to produce hairpins is substantially the same as the cross-section of the conductive wire used to produce rigid conductors.

[0017] Advantageously, the hairpin and rigid conductor are made of flat wire.

[0018] Advantageously, the rigid conductors are electrically connected to the free ends of the various branches by brazing.

[0019] Advantageously, in order to connect one of the branches to one of the rigid conductors, the free end of the branch in question is folded to contact the rigid conductor in question, thereby defining a contact surface, wherein the perimeter length of the contact surface is greater than the length of the cross section of the branch in question, which is defined as being parallel to a radial plane. Attached Figure Description

[0020] The invention will be better understood and other advantages will become apparent by reading a detailed description of an embodiment given by way of example, the description being illustrated in the accompanying drawings, in which: Figure 1 The magnetic core of the wound rotor is shown; Figure 2 The magnetic core, intended for insertion, is partially shown. Figure 1 The magnetic core contains several hair clips in its slots and a rigid conductor for electrically connecting the hair clips together. Figure 3 Electrical connections for hair clips belonging to different radial series are shown; Figure 4 A substrate supporting a rigid conductor for electrically connecting a hair clip is shown; Figure 5 , Figure 6 and Figure 7 Several variations of the method for connecting a branch to one of the conductors are shown; Figure 8 An example of the sequence of steps in the method of the present invention is shown; Figure 9 A variation of the magnetic core, two hairpins, and a rigid conductor for connecting the two hairpins is shown; Figure 10 It shows the connection to Figure 4 The individual hair clips on the base; Figure 11 The image shows a stack of several substrates on a magnetic core. Detailed Implementation

[0021] For clarity, the same elements will be labeled with the same reference numerals in all the accompanying drawings.

[0022] Figure 1 A magnetic core 10 of a rotor according to the invention is shown, which is assembled into an electric machine. The magnetic core is made of a ferromagnetic material and has the overall shape of a portion of a cylinder with a circular cross-section around an axis 12. The rotor is then intended to rotate about axis 12 inside the stator of the electric machine. Figure 1 The diagram shows the magnetic core of an inner rotor, i.e., a rotor capable of rotating inside the stator. The invention can also be applied to an outer rotor, i.e., one rotating about the stator.

[0023] The magnetic core 10 is configured to radially and alternately define a plurality of magnetic poles on the cylindrical surface of the magnetic core 10. Figure 1 In the example shown, the magnetic core 10 is configured to form four magnetic poles 14, 15, 16, and 17, which are arranged at 90° to each other around axis 12. Of course, the invention can be implemented with any other number of poles, typically evenly distributed radially around axis 12. Each pole comprises a coil formed of an electrical conductor wound around a solid portion of the magnetic core. The electrical conductor is arranged in a slot formed in the magnetic core 10. The slot is in the form of a longitudinal slot extending parallel to axis 12. Figure 1 Eight slots are shown between each pole. The slots closest to pole 14 are labeled 141, 142, 143, 144, 145, 146, 147, and 148. The referenced slots are divided into two groups: one group on each side of pole 14. Figure 1 In the diagram, slots 141, 142, 143, and 144 of the first group are visible to the right of pole 14, and slots 145, 146, 147, and 148 of the second group are visible to the left of pole 14. Electrical conductors forming a coil around pole 14 are wound in slots 141 to 148. Similarly, around each pole 15, 16, and 17, electrical conductors are wound in the slot closest to the corresponding pole to form a coil for each pole.

[0024] The magnetic core 10 extends between two radial end faces 21 and 22.

[0025] Each coil is manufactured using hairpins, such as Figure 2 As shown, the hairpin is inserted into the slot associated with the corresponding magnetic pole via its radial end face 21. Figure 2 In the image, pole 14 and slots 141, 142, 145 and 146 belonging to core 10 can be seen.

[0026] After insertion, the hair clips are electrically connected to each other on the radial end face 22 of the magnetic core 10 via rigid conductors arranged along the radial end face 22. Several layers of hair clips are mounted in the same slot to manufacture the coil.

[0027] The rigid conductors extend primarily parallel to radial surfaces 21 and 22. In other words, a minimum parallelepiped volume containing each rigid conductor can be defined. The minimum dimension of this volume is perpendicular to radial surfaces 21 and 22.

[0028] A hair clip with only one branch, for example for electrical connections to a coil, can be inserted into one of the slots. Power supply to different coils can be achieved in different ways. External connections to the coils are not shown and are not the subject of this invention; the invention relates to internal connections to the coils.

[0029] The number of turns in each coil can vary depending on the constraints of the rotor and stator. The number of turns can be adapted by changing the number of slots in each group and the number of hairpin layers inserted into each slot. In practice, the hairpins are manufactured using insulated, such as enamel, wire. The wire cross-section can have any shape, and is particularly circular or rectangular. A rectangular cross-section allows for better slot filling. More precisely, in the example shown, the length of the rectangular cross-section of the hairpin is close to the width of the slot, within the required functional gap that allows the hairpin to be inserted. As mentioned above, wire with a rectangular cross-section is referred to as flat wire.

[0030] Figure 2 Several hair clips are shown, with hair clip 31 shown in full and hair clips 32 and 33 shown in part. Hair clips 31, 32 and 33 belong to a coil surrounding magnetic pole 14. Figure 2 The radial surface 22 of the magnetic core 10 is shown. The hairpin 31 includes two branches 311 and 312. Branch 311 is inserted into slot 142 and branch 312 is inserted into slot 145. Branch 321 of hairpin 32 is inserted into slot 141 and branch 332 of hairpin 33 is inserted into slot 146. The branches of each hairpin are arranged parallel to axis 12.

[0031] The hair clip can be inserted via the radial surface 21 of the magnetic core 10, said surface being... Figure 2 Not shown in the diagram. The insertion of the branches can be achieved by translation in the corresponding slots parallel or perpendicular to axis 12, especially for hair clips with only one branch. After insertion, the free end of each branch protrudes from radial surface 22. The free ends are used to electrically connect the hair clips to each other to produce coils arranged around magnetic pole 14.

[0032] The electrical connection of each coil can be achieved by using a double-branch hair clip on the radial surface 22 side or a single-branch hair clip on the radial surface 21 side at the free end of the branch.

[0033] To connect the branches, rigid conductors are arranged along radial surface 22. The rigid conductors connect the two branches of two separate hairpins to form a winding around pole 14. In the illustrated example, rigid conductor 41 connects branches 311 and 332. Rigid conductor 42 connects branches 312 and 321. Typically, for the fabrication of a coil, the branches are connected to the rigid conductors essentially in the longitudinal extension of the slot into which they are inserted. The extension of the slot is defined parallel to axis 12. Thus, each rigid conductor extends essentially between the longitudinal projections of the slots that accommodate the branches connected by the rigid conductors in question. The presence of rigid conductors, unlike hairpins, prevents direct connection between the free ends of the branches. This type of direct connection requires complex bending of the branches and crossings between them, which the present invention avoids.

[0034] To facilitate the arrangement of rigid conductors 41 and 42, they can advantageously extend in a common radial plane 23 parallel to the radial surface 22. In this arrangement, rigid conductors 41 and 42 do not intersect. This facilitates manufacturing. Figure 2 The conductor hierarchy is shown. Of course, more than two rigid conductors can be arranged in a given plane. Figure 2 In the core 10, rigid conductors 41 and 42 surround the magnetic pole 14. In a given plane, rigid conductors can be arranged around other poles or even all the magnetic poles of the core 10.

[0035] Figure 2 The branches shown may belong to the same or adjacent layers in the arrangement of the hairpin in its corresponding slot. Figure 2 The rigid conductors 41 and 42 shown belong to conductor layer 40. Several layers of rigid conductors are provided to connect different branches. Each layer extends in its specific plane 23. This facilitates the production of connections between branches and corresponding rigid conductors.

[0036] Insert several branches into each slot. Figure 3 This illustrates how different branches of a branch inserted into a given slot can be connected using a rigid conductor to form a coil. Figure 2 Same, Figure 3 The slot 145 formed in the magnetic core 10 is shown. The mounting and connection of several layers of branches can also be implemented for other slots of the rotor's magnetic core.

[0037] exist Figure 3In the diagram, the radial surface 22 of the magnetic core 10 is partially shown around the slot 145. Branches 341 of the hairpin 34 and 351 of the hairpin 35 are both inserted into the slot 145. Branch 341, belonging to layer 48, is closer to axis 12 than branch 351, belonging to layer 58. A rigid conductor 43, belonging to level 40, connects branches 341 and 352. Another rigid conductor 51, partially shown and belonging to level 50, is connected to branch 351. Rigid conductors 43 and 51 are stacked parallel to the radial surface 22 through levels, each level located in its specific plane 23.

[0038] The rigid conductor can be directly connected to the branch of the hairpin, and this connection is sufficient to hold the rigid conductor in place. Figure 4 An advantageous variation is shown in which a rigid conductor of a given level is fixed to an insulating substrate 24 that extends primarily in a radial plane 23. Figure 4 Rigid conductors 61 to 64 surrounding one of the magnetic poles are shown, as well as conductor 65 intended to surround the other magnetic pole. Branch 361 is connected to rigid conductor 65. Branches connected to conductors 61 to 64 are not shown. Figure 4 Only a portion of the substrate 24 and the rigid conductors it carries are shown. The substrate 24 may be in the shape of a washer and extends primarily in plane 23 and around the axis 12 of the rotor. The rigid conductors carried by the common substrate can be used to connect hairpins belonging to a single magnetic pole or several magnetic poles. Advantageously, the rigid conductors carried by the common substrate can be used to connect hairpins belonging to all magnetic poles of the rotor. The rigid conductors carried by the common substrate form conductor layers 60.

[0039] Rigid conductors can be manufactured in various ways, such as by plastic deformation of conductive wire, for example, by conveying it on a spool, similar to a hairpin. Advantageously, the cross-section of the conductive wire used to produce the hairpin is substantially the same as the cross-section of the conductive wire used to produce the rigid conductor. "Substantially the same cross-section" means that the nominal dimensions of the cross-sections of the conductive wires used for the rigid conductor and the hairpin are identical. Dimensional deviations can occur within tolerances given by the conductor manufacturer and also depend on the conductor's shape. This identical cross-section avoids variations in the cross-section of the electrical conductor in the coil. The conductive wire can be, in particular, a flat conductive wire. Rigid conductors can also be manufactured using additive or subtractive manufacturing of conductive materials, particularly copper-based conductive materials. The substrate can be manufactured by additive or subtractive manufacturing, or by molding an electrically insulating material.

[0040] The substrate 24 may include axial protrusions 241 disposed between the rigid conductors. The axial protrusions 241 are configured to extend axially, i.e., parallel to axis 12, beyond the free end of the branch after the branch is electrically connected to the rigid conductor. For a given level of rigid conductor, the axial protrusions 241 form a spacer against which the substrate 24 of the next level of rigid conductor abuts, while the free end of the branch connected to the rigid conductor of the given level does not contact the substrate 24 of the next level of rigid conductor. In other words, a positive functional gap is provided between the free end of the branch and the substrate 24 of the next level. This allows for high manufacturing tolerances in the axial direction of the electrical connection from the branch to the rigid conductor without compromising the mounting of the individual levels of the rigid conductors in contact with each other on the substrate 24.

[0041] Each rigid conductor can be thinned at its connection with the corresponding free end of the branch to reduce the axial protrusion of the branch's electrical connection on its respective rigid conductor. Figure 4 The recess forming the thinning region is shown. For example, a recess 641 is formed on a rigid conductor 64. Other rigid conductors include the same recess in order to... Figure 4 For clarity, these recesses are not referenced. The shape of a rigid conductor, especially the recesses, can be obtained through various manufacturing methods, such as machining, plastic deformation, and additive manufacturing.

[0042] Figure 5 A method for connecting a branch to a rigid conductor is shown. The branch 361 is inserted into a slot in the magnetic core 10. Figure 5 It is represented in the radial plane of the rotor containing the slot into which branch 361 is inserted. Figure 5 In the diagram, other branches 351, 341, and 331 are partially shown. Branches 361, 351, 341, and 331 are all inserted into the same slot. In other words, they appear... Figure 5 The branches in the text belong to different layers.

[0043] After the hairpin is inserted into its corresponding slot, a rigid conductor, which can be fixed to its base 24, is positioned along the surface 22 of the magnetic core 10. The branch 361 has a free end 361a, which can be folded after insertion into the slot. The free end 361a is prepared for connection. More specifically, the electrical insulation of the branch 361 is removed at the free end 361a. This preparation of the free end 361a can be performed before or after the branch 361 is inserted into the corresponding slot. The free end 361a is bent to contact the equally prepared conductor 65. Once the free end 361a contacts the conductor 65, a connection is achieved. It can be as follows: Figure 5 The brazing is shown as 25. Tool 27 can perform bending and keep the free end 361a in contact with conductor 65 during the brazing operation. Any other connection means, such as crimping, can be used.

[0044] Tool 27 can hold each free end independently during bending. Alternatively, to facilitate bending and simplify tool 27, each base 24 may include abutments 242, such as... Figure 4 As shown. Each abutment 242 is configured such that during bending, one of the free ends abuts against it.

[0045] Figure 6 and Figure 7 It shows that it is suitable for, for example Figure 5 The diagram shows a variation with a bent brazed joint. Figure 6 In the variant shown, the free end 361b of branch 361 includes a notch 361c, which is configured to increase the length of the perimeter 361d of the contact surface 361e between the free end 361b and the rigid conductor 65. Therefore, during brazing, the length of the brazing bead is greater than the length of the brazing bead obtained without the notch. The brazing bead follows the perimeter 361d. The perimeter 361d and thus the brazing bead... Figure 6 The brazing is shown in thick lines. By increasing this length, the mechanical strength of the brazing is improved. This advantage is particularly beneficial to the rotor, improving its mechanical strength and, in particular, its ability to resist centrifugal forces caused by rotor rotation.

[0046] exist Figure 7 In the variant shown, the free end 361f of branch 361 includes a hole 361g, which is connected to... Figure 6 Similar to the variant shown, it is configured to increase the length of the perimeter 361d of the contact surface 361e between the free end 361f and the rigid conductor 65. In practice, the profile of the hole contributes to the perimeter. One or more external geometric features, such as... Figure 6 The variant cutout 361c shown, with one or more internal geometric features, such as Figure 7 The illustrated variation of the hole 361g is a combination. More generally, any shape that allows for an increase in the perimeter length of the contact surface between the free end and the rigid conductor is advantageous.

[0047] Alternatively, in Figures 5 to 7 In the bend shown, the free end of the hairpin can remain unbent, for example, by providing a hole in the rigid conductor through which the free end passes. The free end of the hairpin is mounted in the hole of the rigid conductor by translation along axis 12. After mounting, the free end can be easily connected to its corresponding rigid conductor, for example by brazing, in a manner similar to that of an electronic component to be mounted on a printed circuit board. However, bending the free end has several advantages, particularly the fact that the axial protrusion of the branched free end after it has been connected to its corresponding rigid conductor provides better control.

[0048] The sequence of steps—inserting branches into slots, installing rigid conductor layers, and connecting branches and rigid conductors—is repeated through alternating series of branches and rigid conductor layers. A series of branches comprises several branches belonging to the same or adjacent layers.

[0049] Figure 8 An example of the sequence of steps in the method of the present invention is shown. Levels of the branching series and the rigid conductor layer are defined. The sequence of steps for the current M-level rigid conductor and the current N-level branching series can be described to better understand the invention.

[0050] In the first step, an M-level rigid conductor is arranged along surface 22. This level is, for example, a... Figure 3 The level shown is 40.

[0051] In the second step, a series of N-level branches are inserted into the slot, with the free ends of these branches extending beyond the M-level rigid conductor along axis 12. Figure 8 In the middle, there are 8 branches arranged between the two magnetic poles. Figure 8 The sequence of steps between the two magnetic poles is shown. Figure 8 In this series, each has 8 branches. When the rigid conductor is supported by a common base around axis 12, the branch series under consideration includes branches arranged between all the magnetic poles of the rotor.

[0052] For the first-level rigid conductor and the first series of branches, the first two steps can be reversed.

[0053] Next, in the third step, preparations are made to electrically connect the first portion of the free ends of a series of N-level branches to the M-level rigid conductor. Figure 8 In the example shown, the four free ends of the branch are folded to contact their corresponding rigid conductors. As previously seen, other preparation methods are possible. Four additional branches of a series of N-levels are not folded. Preparation of their electrical connections will be carried out in a later, fifth step.

[0054] Next, in the fourth step, M+1 level rigid conductors are arranged to overlap the M level rigid conductors. This is, for example, Figure 3 The rigid conductor layer 50 shown is covered by the layer 40 installed in step 1.

[0055] Next, in the fifth step, the second part of the free ends of a series of N-level branches is prepared to be electrically connected to the rigid conductor of the M+1 level.

[0056] Next, steps 2 through 5 are repeated by increasing the branch series level and the rigid conductor layer level.

[0057] The free end of the branch can be electrically connected to its corresponding rigid conductor, for example, by brazing, after each preparatory connection step, i.e., between steps 3 and 4 in the higher-level branch series and rigid conductor level, and between step 5 and step 2. In other words, there is no distinction between the preparatory step and the electrical connection step.

[0058] Alternatively, to reduce the number of electrical connection steps, between steps 3 and 4, both the first portion of the free ends of a series of N-level branches can be electrically connected to the M-level rigid conductor, and the second portion of the free ends of a series of N-1-level branches can be electrically connected to the M-level rigid conductor. Therefore, there is only one electrical connection step per rigid conductor level, and the electrical connection steps after step 5 are avoided.

[0059] exist Figure 2 , Figure 3 and Figure 4 In the example shown, the free end of the branch is folded toward axis 12. As mentioned above, the free end of the branch can also be folded away from axis 12. Figure 5 This type of fold is shown and can be referred to as a radial fold.

[0060] Figure 9 A variation is shown for connecting two hairpins 37 and 38, and more precisely, their respective branches 371 and 382, ​​via a rigid conductor 44 that extends on its base 24 parallel to the face 22 of the magnetic core 10. Figure 9 In the variant, the folding is performed perpendicular to the radial direction. Figure 9 In the example shown, the conductive wire used to produce the hair clip is a flat wire. Folding can be done on the flat portion of the wire or on its edges.

[0061] Figure 10 A substrate 24 carrying rigid conductors 61 to 64 is shown, along with several hairpins intended for connection to the rigid conductors carried by the substrate or to other rigid conductors. Figure 10 As can be seen, the rigid conductor is arranged closer to axis 12 than the hairpin shown in the diagram. Alternatively, the rigid conductor can be arranged further away from axis 12 than the hairpin. Both arrangements are within the scope of the invention. The arrangement shown is advantageous for an inner rotor because the rigid conductor remains within the radial volume of the rotor.

[0062] It is desirable to provide means for positioning the individual substrates 24 relative to each other. Figure 10In this configuration, the base 24 is provided with radial protrusions 26 that project from the area occupied by the rigid conductor, serving to position and retain the individual bases 24. The protrusions 26 of the stacked bases 24 may, for example, have holes arranged facing each other, allowing a rod to slide through and be inserted to secure the bases. The rod may also be inserted into a hole in the magnetic core facing the hole in the base 24, which positions and retains the individual bases 24 relative to each other and relative to the magnetic core. Of course, any other positioning and holding mechanism is possible. For example, retention may be provided by an external ring clamp.

[0063] Figure 11 A magnetic core 10 comprising a stack of several substrates 24 is shown. For each pole 14, the substrate 24 connects eight branches, four on each side of the pole 14. As described 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 layers is determined in particular by taking into account the number of turns the coil must contain and the spatial organization of these turns around the pole 14. The substrate 24 allows for the same connections to the other poles of the rotor. Ignoring the protrusions 26, the outer diameter of the substrate 24 can increase with the distance from the substrate 24 to the magnetic core 10. Figure 11 In the middle, the protrusions of each base 24 are aligned to facilitate the fixation of each base.

[0064] Figure 9 and Figure 10 This is ideal for constructing rotors in which the magnetic poles are spatially defined. The protrusions are advantageously arranged in the longitudinal extensions of the magnetic poles. Alternatively, protrusions that enable positioning and holding of the substrate carrying the rigid conductor can be arranged outside the longitudinal extensions of the magnetic poles.

Claims

1. A method for manufacturing a wound rotor of a rotary electrical machine about a rotation axis (12), the rotor comprising a magnetic core (10) and a plurality of electrical conductor windings, each winding forming a coil around a portion of the magnetic core. The magnetic core (10) extends between two radial surfaces (21, 22) and therein are grooves (141, 142, 143, 144, 145, 146, 147, 148) extending longitudinally parallel to the axis of rotation. Each coil is formed by hairpins (31, 32, 33, 34, 35, 36, 37, 38), each hairpin having one or two branches (311, 312, 321, 332, 341, 351, 352, 371, 382) inserted in series into the slot and terminating at a free end (361a), and rigid conductors (41, 42, 43, 44, 51, 61, 62, 63, 64), the rigid conductors being distributed in layers and each electrically connected to two of the branches, the rigid conductors extending primarily parallel to the radial surface, and the electrical connection from each branch to one of the rigid conductors being substantially achieved in the longitudinal extension of the corresponding slot. The method includes the following steps:

1. An M-level hierarchical rigid conductor is arranged along the first radial surface (22) of the two radial surfaces.

2. A series of N-level branches are inserted into the slot, the free ends of which extend beyond the M-level rigid conductor.

3. Prepare to electrically connect the first portion of the free end of the series of N-level branches to the M-level rigid conductor.

4. Arrange M+1 level rigid conductors to stack the M level rigid conductors.

5. Prepare to electrically connect the second portion of the free end of the series of N-level branches to the M+1 level rigid conductor. Then repeat steps 2 through 5, incrementally increasing the series of branch levels and rigid conductor layer levels.

2. The method as described in claim 1, wherein, Between step 3 and step 4, perform the following operations: - Electrically connect the first portion of the free end of the series of N-level branches to the rigid conductor of the M-level layer; as well as - Where applicable, the second portion of the free ends of a series of N-1 level branches is electrically connected to the rigid conductor of the M level.

3. The method of claim 1, wherein: - Between steps 3 and 4, the first portion of the free ends of the series of N-level branches is electrically connected to the rigid conductor of the M-level layer; as well as - After step 5, the second portion of the free ends of the series of N-level branches is electrically connected to the rigid conductor of the M+1 level.

4. The method as described in any of the preceding claims, wherein, Rigid conductors at a given level do not cross.

5. The method as described in any one of the preceding claims, wherein, A rigid conductor of a given level is attached to an insulating substrate (24) that extends primarily in a radial plane (23).

6. The method of claim 5, wherein, Each substrate (24) includes an axial protrusion (241) arranged between the rigid conductors and configured to extend axially beyond the free end of the branch after the branch is electrically connected to the rigid conductors.

7. The method of any one of claims 5 or 6, wherein, The preparation of electrical connections at each free end includes bending each free end to make contact with the corresponding rigid conductor.

8. The method of claim 7, wherein, Each base (24) includes abutting portions (242), one of the free ends abutting against each of the abutting portions during bending operations.

9. The method as described in any of the preceding claims, wherein, The cross-section of the conductive wire used to produce the hair clip is substantially the same as the cross-section of the conductive wire used to produce the rigid conductor.

10. The method as described in any of the preceding claims, wherein, The hair clip and the rigid conductor are made of flat wire.

11. The method as described in any of the preceding claims, wherein, The rigid conductors are brazed to the free ends of each branch.

12. The method as claimed in the preceding claim, wherein, In order to connect one of the branches to one of the rigid conductors, the free end of the branch in question is folded to contact the rigid conductor in question, thereby defining a contact surface, wherein the length of the perimeter of the contact surface is greater than the length of the cross section of the branch in question, which is defined as being parallel to the radial plane (23).

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