Method for producing a wound magnetic component of a rotating electrical machine

Abstract

The invention relates to a method for producing a wound magnetic component of an electrical machine rotating around an axis of rotation, the component 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 extending between two radial faces (22) and in which are made notches (142, 145, 146) extending longitudinally parallel to the axis of rotation, each coil being formed of pins (31, 32, 33) each having one or two branches (311, 312, 321, 332) inserted in the notches and terminating in a free end and of rigid conductors (41, 42) each connecting two of the branches, the rigid conductors extending mainly parallel to the radial faces, the connection of each branch to one of the rigid conductors being made substantially in the longitudinal extension of the corresponding notch.Figure for abstract: Fig. 3.

Description

Title of the invention: Method for producing a wound magnetic component of a rotating electrical machine

[0001] The invention relates to a method for producing a wound magnetic component of a rotating electrical machine. The wound magnetic component may be a rotor or a stator of the electrical machine. An electrical 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 may be defined to alternate phases where it acts as a motor and a generator.

[0002] Wound rotors generally comprise a magnetic core and coils of electrical conductors making it possible to define magnetic poles facing poles of the stator of the electrical machine. The wound stator also comprises a magnetic core and coils of electrical conductors making it possible to define magnetic poles. A circulation of an electric current in the conductors of the stator and the rotor makes it possible to generate the magnetic poles. This type of wound magnetic component can be implemented in an electrical machine which can operate as a motor, a generator or by alternating the two types of operation. The rotor can rotate in only one direction of rotation or possibly in both directions.

[0003] It is possible to produce the coils of electrical conductors outside their magnetic core and then to insert the already shaped coils into notches in the magnetic core designed to receive them. This embodiment is well suited to assemblies (rotor or stator) whose poles are protruding. There is in fact sufficient space around protrusions of the magnetic core to position the coils. On the other hand, for assemblies with smooth poles, where the magnetic core is practically flush with the air gap over its entire circumference, the positioning of the already shaped coils in notches in the magnetic core can be more difficult to achieve.

[0004] The coils can be made from conductive wires wound continuously or discontinuously, in particular from pins inserted into the notches of the magnetic core. The production of coils from pins is well suited to the production of 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 produce these turns, the free ends of the pin arms are connected together for example by soldering. Before connecting the free ends, it is necessary to shape the arms in a part opening out of the notches 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 components 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 makes it possible to simplify the assembly of a wound magnetic component, whether a rotor or a stator. In addition to simplifying the assembly of a rotor, these connections between pins and specific rigid conductors improve the reproducibility and traceability of the wound magnetic component. More precisely, the specific connections are spatially distributed in a better controlled manner.

[0008] To this end, the invention relates to a method for producing a wound magnetic component of an electrical machine rotating around an axis of rotation, the component 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 into the notches and ending in a free end and of rigid conductors each connecting two of the branches, the rigid conductors extending mainly parallel to the radial faces, the 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: - insert each branch into one of the notches, the free ends emerging from the notches beyond the first of the two radial faces, - arrange the rigid conductors along the first of the two radial faces, - electrically connect the rigid conductors to the free ends so as to create the winding.

[0009] Advantageously, in each notch are inserted several radial layers of branches, the rigid conductors, extending in groups, each of the groups in a plane parallel to the first radial face, each group being dedicated to connecting the branches of one of the layers.

[0010] Advantageously, the rigid conductors of the same group do not cross.

[0011] Advantageously, the rigid conductors of the same group are attached to a insulating substrate extending mainly in the radial plane.

[0012] Advantageously, the section of a conductive wire used to make the pins is the same as the section of a conductive wire used to make the rigid conductors.

[0013] Advantageously, the pins and the rigid conductors are made from flat wires.

[0014] Advantageously, to electrically connect the rigid conductors to the free ends, the free ends are folded along the rigid conductors.

[0015] Advantageously, the connection of the rigid conductors to the free ends of the different branches is carried out by brazing.

[0016] Advantageously, several layers of branches are inserted into the same notch and in which one of the rigid conductors connects two branches arranged in two separate layers.

[0017] The invention also relates to a wound rotor forming a wound magnetic component obtained by a method according to the invention.

[0018] The invention also relates to a wound stator, a wound magnetic component obtained by a method according to the invention.

[0019] 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:

[0020] [Fig-1] [Fig. 1] represents a magnetic core of a wound rotor;

[0021] [Fig.2] [Fig.2] represents a magnetic core of a wound stator;

[0022] [Fig.3] [Fig.3] partially represents the magnetic core, several pins intended to be inserted into notches in the magnetic core of [Fig.l], as well as rigid conductors allowing the pins to be electrically connected together;

[0023] [Fig.4] [Fig.4] illustrates the electrical connection of pins belonging to different radial layers;

[0024] [Fig.5] [Fig.5] represents a substrate carrying rigid conductors allowing the electrical connection of the pins;

[0025] [Fig.6] [Fig.6] illustrates a method of connecting a branch to one of the conductors;

[0026] [Fig.7] [Fig.7] represents a variant of the magnetic core, two pins and a rigid conductor allowing the two pins to be connected;

[0027] [Fig.8] [Fig.8] represents different pins connected on the substrate of the [Fig.5],

[0028] [Fig.9] [Fig.9] represents a stack of several substrates on a magnetic core.

[0029] For the sake of clarity, the same elements will bear the same references in the different figures.

[0030] [Fig. 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. [Fig. 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.

[0031] 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 [Fig.l], 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 [Fig.l], eight notches appear between each pole. The notches closest to pole 14 are marked 141, 142, 143, 144, 145, 146, 147 and 148.The notches are divided into two series. In [Fig.l], notches 141, 142, 143, 144 are visible to the right of pole 14 and notches 145, 146, 147, 148 are to the left of pole 14. The electrical conductor forming a coil surrounding pole 14 is wound in notches 141 to 148. In the same way around each of 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.

[0032] The magnetic core 10 extends between two radial faces 21 and 22.

[0033] [Fig. 2] represents a magnetic core 18 of a stator according to the invention and equipping an electrical machine. As previously, 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 associated rotor is then intended to rotate around the axis 12 inside the stator of the electrical machine. [Fig. 2] represents a magnetic core of an external stator. In other words, the rotor rotates at inside the stator. It is also possible to implement the invention for an internal stator, i.e. around which the rotor rotates.

[0034] As for the magnetic core 10, the magnetic core 18 comprises longitudinal notches, extending parallel to the axis 12. Unlike the magnetic core 10, the notches, shown here, are distributed regularly around the axis 12. The magnetic core 18 does not include a solid part without a notch. It is of course possible to implement the invention for any other distribution of the notches around the axis 12. With the distribution of the notches as shown in [Fig. 2], the magnetic poles of the stator can be nested within each other. The nesting of the poles is particularly possible for a polyphase supply of the stator. In [Fig. 2], only a few notches 191 to 198 are referenced. The referenced notches are, as previously, divided into two series, on the one hand notches 191, 192, 193 and 194 and on the other hand, notches 195, 196, 197 and 198.The electrical conductor forming a coil surrounding the pole is wound alternating a notch of the first series and a notch of the second series.

[0035] The magnetic core 18 also extends between two radial faces whose references used previously will be used: 21 and 22.

[0036] Each coil is made by means of pins, visible in [Fig.3], inserted into the notches associated with the corresponding pole by the radial face 21. In [Fig.3], we can see the pole 14 and the notches 141, 142, 145 and 146 belonging to the magnetic core 10. It is entirely possible to transpose this figure for the magnetic core 18 shown in [Fig.2].

[0037] 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 can be placed in the same notch.

[0038] 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.

[0039] It is possible to insert into one of the notches a pin having only one branch, used for example for the electrical connection of the coil. The electrical supply of the different coils can be carried out 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.

[0040] The number of turns of each coil can vary depending on the definition of the rotor and stator. The number of turns can be adapted by varying the number of slots per series and the number of layers of pins inserted in each slot. In practice, 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 notches. More precisely, in the example shown, the length of the rectangular cross-section of a pin is close to the width of the notches, excluding the functional clearance to allow the insertion of the pins. As mentioned above, wires with a rectangular cross-section are called flat wires.

[0041] [Fig. 3] 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 [Fig. 3] 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.

[0042] The pins are inserted through the radial face 21 of the magnetic core 10, a face not appearing in [Fig. 3]. The branches are inserted by translation parallel to the axis 12 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.

[0043] 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.

[0044] In order to facilitate the arrangement of the rigid conductors 41 and 42, they 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 group of conductors shown in [Fig. 3]. It is of course possible to arrange more than two rigid conductors in the same plane.

[0045] The branches shown in [Fig.3] advantageously belong to the same layer in the arrangement of the pins in their respective notches. To achieve a coil, some pins may have branches belonging to different layers. The rigid conductors 41 and 42 shown in [Fig.3] belong to a group 40 of conductors, the group 40 being dedicated to a given layer 48 of branches. To ensure the connection of the different layers, several groups of rigid conductors are present. Each group extends in a plane 23 of its own. This makes it easier to make connections between the branches and the corresponding rigid conductors.

[0046] In each notch several branches can be inserted. [Fig.4] illustrates how different layers of branches, inserted in the same notch, can be connected by means of rigid conductors to form a coil. As for [Fig.3], [Fig.4] represents a notch 145 managed in the magnetic core 10. The placement of several layers of branches and their connection can also be implemented for other notches whether for a magnetic core of a rotor or also of a stator.

[0047] In [Fig. 4], 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 in 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 group 40 connects the branches 341 and 352. Another rigid conductor 51, shown partially and belonging to the group 50, is connected to the branch 351. The rigid conductors 43 and 51 are stacked parallel to the radial face 22, each in a plane 23 of its own.

[0048] 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. [Fig. 5] represents an advantageous variant in which the rigid conductors of the same group are integral with an insulating substrate 24 extending mainly in the radial plane 23. Here again this variant is adaptable to the connection of the pins of a stator. In [Fig. 5], 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. [Fig. 5] 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 magnetic poles to be connected. 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 group 60 of conductors associated with a layer of branches.

[0049] 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 the pins. Advantageously, the cross-section of the conductive wire used to make the pins is the same as the cross-section of the conductive wire used to make the rigid 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 can in particular be a flat conductive wire. The rigid conductor can also be manufactured by additive or subtractive manufacturing of an electrically conductive material, in particular based on copper. The substrate can in particular be produced by additive or subtractive manufacturing, by molding an electrically insulating material.

[0050] [Fig. 6] illustrates a method of connecting a branch to a rigid conductor. Branch 361 is inserted into a notch of the magnetic core 10. [Fig. 6] is a partial representation in a radial plane of the rotor containing the notch into which branch 361 is inserted. In [Fig. 6], other branches, 351, 341 and 331 are partially represented. Branches 361, 351, 341 and 331 are all inserted into the same notch. In other words, the branches appearing in [Fig. 6] belong to different layers.

[0051] 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 can be a solder 25 as shown in [Fig.6]. A tool 27 may hold the free end 361a in contact with the conductor 65 during the soldering operation.Any other means of connection can be implemented, such as crimping.

[0052] Alternatively, to the folding illustrated in [Fig. 6], 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, like an electronic component to be inserted into a printed circuit.

[0053] The sequence of shaping and connection steps is repeated for each group of conductors. More precisely, a first substrate 24, closest to the face 22, is put in place. Then the free ends of the branches are shaped and connected to the rigid conductors of this substrate. Then a second substrate 24 is put in place followed by the shaping and connection of the corresponding branches and so on until all the rigid conductors are put in place and connected.

[0054] In the examples shown in Figures 3, 4 and 5, 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. [Fig.6] illustrates such a folding which can be described as radial.

[0055] [Fig.7] shows 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 [Fig.7], the folding is carried out perpendicular to a radial direction. In the example shown in [Fig.7], 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.

[0056] [Fig.8] represents 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 [Fig.8] 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.

[0057] It was mentioned above that the branches of the pins can be arranged in the notches in several layers. It is then possible to use as many substrates 24 as there are layers in order to make the connections of the pins per stage. It is desirable to provide means for positioning the different substrates 24 relative to each other. In [Fig. 8] the substrate 24 is equipped with a radial protuberance 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 protuberances 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 the 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. The holding can for example be ensured by means of an external hoop.

[0058] [Fig. 9] represents a rotor 10 comprising a stack of several substrates 24, each dedicated to the connection of a layer of pin branches. For the pole 14, a substrate 24 makes it possible to connect eight branches occupying the same row of layers, 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 in particular 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 may have external diameters that increase as the substrates 24 move away from the magnetic core 10. The growth in diameters corresponds to the addition of a layer of pin branches. In [Fig.9], the protrusions of the different substrates 24 are aligned to facilitate the fixing of the different substrates.

[0059] Figures 8 and 9 are well suited to the production of a wound magnetic component, for example a rotor, for which the magnetic poles are spatially defined. Alternatively, when the magnetic poles are nested, as is possible with the magnetic core of [Fig. 2], 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 magnetic component of an electrical machine rotating about an axis of rotation (12), the component 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 into the notches and terminating in a free end (361a) and rigid conductors (41, 42, 43, 44, 51, 61, 62, 63, 64) each connecting two of the branches, the rigid conductors extending mainly parallel to the radial faces,the connection of each branch to one of the rigid conductors being carried out substantially in the longitudinal extension of the corresponding notch, the method chaining the following steps: - inserting each branch into one of the notches, the free ends emerging from the notches beyond a first (22) of the two radial faces, - arranging the rigid conductors along the first of the two radial faces, - electrically connecting the rigid conductors to the free ends so as to carry out the winding.,

2. Method according to claim 1, in which in each notch are inserted several radial layers (48, 58) of branches, in which the rigid conductors extend in groups (40, 50), each of the groups in a plane (23) parallel to the first radial face, each group being dedicated to the connection of the branches of one of the layers.

3. A method according to claim 2, wherein the rigid conductors of the same group do not cross.

4. Method according to one of claims 2 or 3, in which the rigid conductors of the same group are attached to an insulating substrate (24) extending mainly in the radial plane (23).

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

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

7. Method according to one of the preceding claims, in which to electrically connect the rigid conductors to the free ends, the free ends are folded along the rigid conductors.

8. 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.

9. Method according to one of the preceding claims, in which several layers (48, 58) of branches are inserted into the same notch and in which one of the rigid conductors connects two branches arranged in two separate layers.

10. Wound rotor forming a wound magnetic component obtained by a method according to one of the preceding claims.

11. Wound stator a wound magnetic component obtained by a method according to one of claims 1 to 8.

Images