ELECTRIC MACHINE ROTOR AND METHOD FOR MANUFACTURING AN ELECTRIC MACHINE ROTOR

Abstract

The invention relates to an electric machine rotor (1) comprising a single-piece body of revolution (2) with an axis of revolution (A) made of a first material and comprising at least one notch (5) extending along the axis of revolution (A); and at least one insert (3) made of a second material, capable of filling the notch (5) by shape complementarity, and securely connected in the notch (5). Figure for abstract: Fig.2

Description

Title of the invention: ELECTRIC MACHINE ROTOR AND METHOD FOR MANUFACTURING AN ELECTRIC MACHINE ROTOR Technical field of the invention

[0001] The present invention relates to the field of electrical machines and more particularly to the rotors of asynchronous machines used at high speeds. The present invention also relates to a method of manufacturing such an electrical machine rotor. Technological background

[0002] Faced with the environmental challenge in many areas and the need for electrical power increasing concomitantly with the number of equipment and new functions in vehicles, such as an aircraft or an automobile, the question of the hybridization of engines arises.

[0003] Such an observation leads to studying architectural solutions combining fossil fuel energy and electrical energy to ensure the drive of the vehicle, such as in particular a turbomachine fan of an aircraft, and the power supply of certain engine and / or vehicle functions, in particular the aircraft.

[0004] Such solutions are likely to implement an electrical machine which is an electromechanical device based on electromagnetism allowing in particular a conversion of electrical energy into mechanical energy, in particular in a so-called “motor” mode or the production of electricity from mechanical energy, in particular in a so-called “generator” mode.

[0005] The electric machine can behave in “generator” mode and / or in “motor” mode.

[0006] An increase in the rotation speeds of electrical machines makes it possible to reduce the specific power. However, it then falls within mechanical limits.

[0007] Asynchronous electrical machines make it possible to meet such a need and each comprise a stator and a rotor. The rotor may be of the “squirrel cage” type comprising a cage, be wound or be solid. The stator has a winding, in particular made of copper, supplied with electric current, capable of driving the rotor in rotation.

[0008] In particular, the magnetic fields in the stator in turn generate induced currents causing the rotor to rotate.

[0009] The solid rotor consists of a cylinder, in particular solid, compact and made from a solid block, in particular from a magnetic material. The material ma- genetic is typically steel.

[0010] The currents induced by the stator winding circulate freely in the rotor and generate a torque of the electric machine.

[0011] Such a configuration is mechanically robust and allows high rotation speeds to be achieved.

[0012] However, the induced currents remain mainly in a part close to the surface of the rotor and the torque obtained is not maximum.

[0013] In addition, since the rotor is made of steel, the electrical resistivity in the rotor remains quite high and generates significant losses. The efficiency of such asynchronous electrical machines with a solid rotor remains low.

[0014] Alternatively, the solid rotor may comprise notches arranged radially substantially in a U shape formed in the material of the rotor and opening onto the surface of the solid rotor.

[0015] Such notches have the effect of causing the induced currents to penetrate into the rotor, greatly increasing the electromagnetic performance of the electrical machine. In fact, due to a reluctance effect of the magnetic circuit, the magnetic flux circulates mainly through the magnetic material and not in the air present in the notches.

[0016] However, the notches reduce the mechanical strength of the solid rotor and generate significant airflow losses due to the mixing of the air; the surface of the solid rotor is not smooth.

[0017] The “squirrel cage” rotor has very good electromagnetic performance but lower mechanical resistance at high speeds.

[0018] Indeed, the cage, which carries the induced currents, comprises in particular two lateral short-circuit rings between which bars extend. A body of the rotor, which carries the magnetic field, comprises a massive part made of magnetic material or made from a stack of magnetic sheets, in which several passages are made, in the form of notches, intended to receive the bars of the cage.

[0019] The short-circuit rings are placed respectively upstream and downstream of the rotor body and connect the bars.

[0020] However, the different parts of the cage require different manipulations to assemble them with the rotor body and can be movable between them.

[0021] Furthermore, the construction of such a rotor does not allow it to withstand the centrifugal forces generated by a high rotation speed of the rotor. Maintaining the bars, particularly those made of copper, in the notches is complex.

[0022] It thus becomes impossible to obtain high rotation speeds without the bars tending to become detached from the rotor.

[0023] Alternatively, the passages may be closed to provide better support. However, such a configuration greatly increases the leakage inductances resulting in low efficiency of the electrical machine.

[0024] There is therefore a need to resolve all or part of the aforementioned drawbacks. Summary of the invention

[0025] The objective of the present invention is to provide an electrical machine rotor which does not exhibit airflow disturbances in the air gap and which has mechanical robustness, particularly at high speeds, in a simple and economical manner.

[0026] Such an objective is achieved in accordance with the invention by means of an electric machine rotor comprising: - a single-piece body of revolution with an axis of revolution made from a first material, in particular magnetic, and comprising at least one notch extending along the axis of revolution, and - at least one insert, in particular longitudinal, made from a second material, in particular non-magnetic, capable of filling the notches by complementarity of shape.

[0027] More particularly, the inserts are securely connected in the notches.

[0028] Thus arranged, the rotor according to the invention makes it possible to achieve the aforementioned objective.

[0029] In particular, such a rotor is a single-piece material and comprises the first material, in particular magnetic, and the second material, in particular non-magnetic, firmly connected and capable of being driven in rotation at very high speeds. In the present description, the expression "firmly connected" must be understood as such a strong connection between the first material and the second material that they adhere to each other even at very high speeds and / or whatever the conditions of use and the environment in which the rotor is placed.

[0030] In addition, the notches filled by the inserts made from the second material, in particular non-magnetic, make it possible to optimize the path of the magnetic flux within the rotor of the electric machine and thus increase the efficiency of the electric machine.

[0031] Furthermore, such a configuration of the rotor of the electric machine according to the invention makes it possible to eliminate possible airflow losses generated by the notches. Indeed, the inserts made of the second material fill the notches of the body of revolution, by complementarity of shape, in particular in order to define a continuous surface on a periphery of the body of revolution.

[0032] The electric machine rotor also includes one or more of the following features, taken alone or in combination: - the notches open onto a radially external surface of the body of revolution; - the body of revolution comprising inserts inserted into the notches has a radial section which is constant along the axis of revolution; - the insert comprises a recess which extends along the axis of revolution and passes through the insert on either side along the axis of revolution; - the electric machine rotor comprises at least one bar, in particular longitudinal, inserted into the recess and having a length, along the axis of revolution, substantially equal to a length of the recess; - a portion of insert is arranged radially outside the bar so as to form a bridge; - the electric machine rotor comprises two plates arranged respectively at the first end and at the second end of the body of revolution and connected by the longitudinal bar; - the bar is made from a third material, in particular non-magnetic, in particular having very high electrical conductivity, more specifically different from the second material; - the plates are made of the third material; - the body of revolution comprises a plurality of notches distributed around the axis of revolution; and / or - the second material is in powder form.

[0033] The invention also relates to a method of manufacturing such an electric machine rotor, comprising at least: - a production step, during which a single-piece body of revolution with an axis of revolution, comprising at least one notch extending along the axis of revolution and opening onto a radially external surface of the body of revolution, is produced from a first material, in particular magnetic, in particular in powder form and, - a filling step, during which the notch is filled by shape complementarity with an insert, formed from a second material, in particular non-magnetic, in particular, in powder form.

[0034] Thus, the manufacturing method according to the invention makes it possible to achieve the aforementioned objective. In particular, the manufacturing of the electric machine rotor and inserts during the same additive manufacturing process makes it possible to bond the first material, in particular magnetic, and the second material, in particular non-magnetic, so as to ensure a bond as strong as if the electric machine rotor had been constructed with a single material.

[0035] Thus, the electric machine rotor thus obtained by the manufacturing method according to the invention can be driven in rotation at high speeds.

[0036] For example, for an electric machine rotor of approximately 300 mm in diameter, a rotation speed could reach 10,000 revolutions per minute.

[0037] The peripheral speed of the rotor of an electric machine could approach 340 m / s with significant mechanical forces.

[0038] In particular, if the second material is non-magnetic, the improved connection and the notch filled with non-magnetic material make it possible to optimize the path of the magnetic flux within the rotor of the electric machine and thus increase the efficiency of the electric machine. The air losses generated by the notches are minimized thanks to the second non-magnetic material which fills the notch in the body of revolution.

[0039] The manufacturing method also comprises one or more of the following steps and / or features, considered independently or in combination: - the body of revolution is formed layer by layer, in particular by means of an additive manufacturing method, from the first material; - the insert is formed layer by layer, in particular by means of an additive manufacturing process from the second material; - the electric machine rotor has an external peripheral surface formed of constant radial sections and comprising alternating portions of the first material and the second material around the axis of revolution; - a recess is formed in the insert during the filling step; - the recess extends along the axis of revolution; - the recess is transverse on both sides following the axis of revolution; - the manufacturing method comprises a step of producing bars, during which at least one bar, in particular longitudinal, intended to be integrated into the recess is produced from a third material, in particular non-magnetic, in particular different from the second material; - the second material may have high electrical conductivity and low electrical resistivity; - the third material is a good electrical conductor; - the bar has a length along the axis of revolution that is substantially equal at a length of the recess; - at least one insert portion is arranged radially outside the bar so as to form a bridge; - the bar is produced, layer by layer using an additive manufacturing process, in particular from the third material, in particular in powder form; - the bar is produced by a casting, rolling, forging and / or machining process; - the manufacturing process includes a step of producing plates, at during which plates, intended to be arranged respectively at a first end and at a second end of the body of revolution and to be connected by the bar, are produced, in particular from the third material; - the first material and the second material comprise steel or a steel alloy; - the steel alloy is of the iron-cobalt type (FeCo) or of the iron-silicon type (FeSi); - the first material comprises a steel of type 17-4 PH; - the second material comprises a steel of type 316L; - the third material includes copper, a copper alloy, aluminum and / or an aluminum alloy; - the additive manufacturing process is selected from the group consisting of selective laser melting (SLM), electron beam melting (EBM), direct laser additive manufacturing (CLAD), electron beam additive manufacturing (EBAM), laser metal deposition (LMD), binder diffusion, or selective laser sintering (SLS); - the manufacturing process includes a design step, during which a digital model of the rotor is defined; - the manufacturing method comprises a storage step, during which the digital model of the rotor is stored, in particular in computer-aided design software of the CAD type; and / or; - the manufacturing direction of the electric machine rotor is parallel or perpendicular to the axis of revolution of the body of revolution.

[0040] The invention relates to an electrical machine comprising a stator and a rotor obtained according to the manufacturing method having any one of the steps and / or characteristics detailed above. Brief description of the figures

[0041] The invention will be better understood and other aims, details, characteristics and advantages thereof will appear more clearly on reading the detailed explanatory description which follows, of embodiments of the invention given as purely illustrative and non-limiting examples, with reference to the appended schematic drawings in which: - [Fig.l] is an axial and local half-sectional view of an example of a bi-material electric machine rotor according to the invention; - [Fig.2] is a radial and local half-sectional view of the machine rotor electric according to [Fig.l]; - [Fig.3] is an axial and local half-sectional view of another example of an electric machine rotor equipped with a squirrel cage according to the invention; - [Fig.4] is a radial and local half-section view of the electric machine rotor according to [Fig.3]; - [Fig.5] is an example of a flowchart of a method of manufacturing an electric machine rotor according to the invention; and, - [Fig.6] is a variant of the flowchart of the manufacturing process in [Fig.5]. Detailed description of the invention

[0042] [Fig.l] is an axial and local half-sectional view of an example of an electric machine rotor according to the invention.

[0043] The electrical machine or induction machine is, in particular, an asynchronous machine comprising a stator and a rotor. The stator has a winding powered by an electric current and capable of driving the rotation of the rotor by induced currents flowing through it. Advantageously, the electrical machine can operate in “motor” mode or in “generator” mode.

[0044] The electric machine is intended to be mounted, advantageously, but not limitingly, in an electric compressor of a vehicle or in an aircraft turbomachine.

[0045] The rotor of the electric machine is capable of operating at high rotational speeds, such as rotational speeds of at least 40,000 revolutions per minute, in particular 200,000 revolutions per minute, in particular in the context of the application of an on-board electric compressor. Of course, such an electric machine rotor can be applied in another field.

[0046] According to the embodiment of [Fig.l], a rotor 1 of an electric machine comprises a single-piece body of revolution 2 with an axis of revolution A made of a first material, in particular magnetic. The rotor 1 also comprises inserts 3, in particular longitudinal inserts 3, made of a second material, in particular non-magnetic.

[0047] In the present description, - the term “monobloc” must be understood as defining a part made from a single piece and / or from a single material, i.e. made from a single material; - the expression “magnetic material” must be understood as defining a material capable of producing a magnetic field and / or of reacting to the presence of an external magnetic field, such as a ferromagnetic material. soft magnetic, which may have a high relative permeability; and - the term "non-magnetic material" should be understood as defining a material that exhibits no interaction or very weak interaction with magnetic fields. A non-magnetic material is neither magnetically attractive nor repulsive, and may have almost zero relative permeability. Such a non-magnetic material is generally considered to be a material that does not disturb an external magnetic field or only very weakly. It therefore has a magnetic behavior close to that of air.

[0048] The body of revolution 2 generally has the shape of a cylinder having a diameter D, preferably but not limited to a straight one. In particular, the body of revolution 2 extends between a first end 2a and a second end 2b along an axis of revolution A.

[0049] Advantageously, but not limitingly, the body of revolution 2 comprises a shaft 4 centered on the axis of revolution A and extending in projection respectively from the first end 2a and the second end 2b of the body of revolution 2. The shaft 4 allows the rotor 1 to be driven in rotation and the latter to be held in bearings, in particular fixed on a chassis or casing of the electrical machine, allowing a free connection in rotation with the stator.

[0050] [Fig.2] is a radial and local half-sectional view of the rotor 1 of the electric machine according to [Fig.l].

[0051] According to the embodiment of [Fig.2], the body of revolution 2 comprises a plurality of notches 5, in particular extending along the axis of revolution A. In addition, the notches 5 are distributed, in particular angularly distributed, around the axis of revolution A. The distribution of the notches 5 is, advantageously regular, i.e. equally distributed.

[0052] According to a particular embodiment, the notches 5 pass through the body of revolution 2 on either side along the axis of revolution A.

[0053] Thus arranged, each notch 5 opens onto a radially external surface 6 of the body of revolution 2.

[0054] The notches 5 may have, respectively or individually, a radial section substantially in the shape of a “U”, a “V”, a “C”, or even a hemispherical shape.

[0055] According to the embodiment of [Fig.2], the notches 5 open out at the level of the radially external surface 6.

[0056] According to the invention, each notch 5 is filled by at least one insert 3.

[0057] More specifically, the insert 3 has a shape complementary to that of the notch 5 in which it is inserted and matches the shape of the notch 5 in which it is inserted.

[0058] The insert 3 is securely connected to the walls of the notch 5 in which it is inserted, in order to ensure a robust, strong and firm assembly. Thus arranged, the insert 3 is integral with the notch 5. The assembly between the insert 3 and the notch 5 in which it is inserted may in particular result from a force-fit assembly.

[0059] In such an arrangement, an electric current can flow freely between the first material, in particular magnetic, and the second material, in particular non-magnetic.

[0060] In particular, the second material has a very low electrical resistivity to reduce losses by Joule effect through current circulation, in particular having a value less than or equal to 30 x 109 Qm

[0061] The insert 3 has an external surface 7 which can have surface continuity with the radially external surface 6 of the body of revolution 2.

[0062] More specifically, the notch 5 has a depth Pe between a notch bottom 8 and the radially external surface 6 of the body of revolution 2. The notch bottom 8 forms a surface, which can extend substantially over a portion of a circle positioned radially, at a distance Re from the axis of revolution A.

[0063] Furthermore, the insert 3 has a height HL Advantageously, the height H1 of the insert 3, taken in a radial direction when the insert 3 is inserted into the notch 5, is less than a radius R of the body of revolution 2.

[0064] According to the embodiment example of [Fig.2], the height H1 of the insert 3 corresponds to the difference between the radius R of the body of revolution 2 and the distance Re of the bottom of the notch 8 relative to the axis of revolution A.

[0065] Thus arranged, the radial section of the rotor 1 comprising the inserts 3 inserted into the notches 5, is constant along the axis of revolution A. In other words, the rotor 1 according to the invention has an external peripheral surface formed of constant radial sections.

[0066] According to the exemplary embodiment presented in Figures 1 and 2, the rotor 1 according to the invention comprises an alternation of portions of the first material, constituted by projecting parts of the body of revolution 2, and of the second material, constituted by the inserts 3, arranged around the axis of revolution A.

[0067] The external peripheral surface of the rotor 1, here smooth, comprises the external surfaces 7 of the inserts 3 and the radially external surface 6 of the body of revolution 2. With such a smooth and constant surface, the air losses are negligible.

[0068] According to the embodiment shown in Figures 1 and 2, the insert 3 may have a generally substantially trapezoidal shape. Alternatively, the insert 3 may have a generally substantially semi-elliptical shape or other shape provided that the shape allows the notch 5 in which it is inserted to be filled without play with surface continuity.

[0069] In addition, the rotor 1 may comprise various forms of inserts 3 inserted into notches 5 having different shapes, complementary to the insert 3 intended to be inserted there.

[0070] [Fig. 3] is an axial and local half-sectional view of another embodiment of the rotor 1 of an electric machine according to the invention. Furthermore, [Fig. 4] is a radial and local half-sectional view of the rotor of an electric machine according to [Fig. 3].

[0071] The embodiment shown in Figures 3 and 4 differs from the embodiment shown in Figures 1 and 2 in that the rotor 1 is equipped with a cage 10, also called a “squirrel cage”.

[0072] In particular, the rotor 1 comprises recesses 11 made in the inserts 3. More particularly, a recess 11 passes respectively on either side of an insert 3 along the axis of revolution A.

[0073] Furthermore, the recess 11 has a height H2.

[0074] According to an exemplary embodiment, the height H2 of the recess 11 is less than the height H1 of the insert 3. In such a configuration, the recess 11 does not open onto the radially external surface 6 of the body of revolution 2. In such a case, the insert 3 comprises at least one insert portion 3a.

[0075] Furthermore, the insert 3 may also comprise a recess portion. The recess portion may comprise the recess 11, which opens into the corresponding notch 5, or a wall radially and axially delimiting the recess 11.

[0076] Furthermore, according to the embodiment presented in figures 3 and 4, the rotor 1 comprises bars 12, in particular longitudinal bars 12, respectively inserted in a recess 11.

[0077] The induced currents circulate in the bars 12. Each bar 12 may have a length, considered along the axis of revolution A in the installation situation, at least equal to the length of the recess 11.

[0078] The bars 12 are in particular made of a third material, in particular non-magnetic. The third material is advantageously different from the second material.

[0079] In particular, the third material, in particular non-magnetic, has a very low electrical resistivity to reduce losses by Joule effect through current circulation, in particular having a value less than or equal to 30 x 109 Qm

[0080] The bars 12 make it possible to further reduce the electrical resistivity of the cage 10 and, consequently, the losses due to induced currents. With such a configuration, the efficiency of the electrical machine is thus significantly improved.

[0081] According to an exemplary embodiment, the bar 12 being of height H2 less than the height H1 of the insert 3, the insert portion 3a, located at the level of the radially external surface 6 of the body of revolution 2, is arranged radially on the external periphery of the bar 12 so as to form a bridge between two contiguous portions of the body of revolution 2.

[0082] In other words, a residual part of the notch 5 and / or the insert 3 is filled by the bar 12.

[0083] The bridge formed by the insert portion 3a is in particular made of non-magnetic material, in particular corresponding to the second material of the insert 3.

[0084] In addition, the bridge formed by the insert portion 3a makes it possible to ensure cohesion and robust, resistant and firm support of the cage 10, in particular in another non-magnetic material, within the body of revolution 2.

[0085] Such a configuration implies a great robustness of the assembly and makes it possible to prevent a magnetic short circuit on the surface of the rotor 1. In addition, it makes it possible to facilitate the passage of the internal radial magnetic flux so that it embraces all of the bars 12.

[0086] The rotor 1 may also comprise two plates 13, also called short-circuit rings, arranged respectively at the first end 2a and at the second end 2b of the body of revolution 2. The plates 13 are connected to each other by the bars 12.

[0087] In the present example, each plate 13 has an annular shape and is centered on the axis of revolution A. According to one embodiment, the plates 13 are also made of the third material, in particular non-magnetic.

[0088] The bars 12 and the plates 13 form the cage 10.

[0089] In particular, the bars 12 and at least one of the plates 13 may be formed from a single piece, made from one material.

[0090] The plates 13 form a short circuit and allow the circulation of current in the bars 12 by creating a closed loop circuit.

[0091] The plates 13 are arranged respectively upstream and downstream of the ends of the inserts 3. Advantageously, but not limitingly, each plate 13 has a surface flush with the surface respectively of the first end 2a and the second end 2b of the body of revolution 2.

[0092] [Fig.5] is an example of flowcharts of a method of manufacturing an electric machine rotor according to the invention.

[0093] An example of a manufacturing method 100 of a rotor 1 of an electric machine such as those of FIGS. 1 to 4 is described in detail below in relation to the flowchart of [Fig.5].

[0094] The manufacturing method 100 may comprise a design step, during which a digital model of the rotor 1 is defined. Consequently, the manufacturing method 100 may comprise a storage step, during which the digital model of the rotor 1 is stored, in particular in computer-aided drawing design software of the CAD type.

[0095] The manufacture of the rotor 1 may, in particular, be based on such a digital model of the rotor 1.

[0096] According to the invention, the manufacturing method 100 comprises at least one forming step 110, during which the body of revolution 2 is formed. At the end of the forming step 110, the body of revolution 2 is a single piece, i.e. a single piece and / or made from a single material, with an axis of revolution A.

[0097] The manufacturing method 100 is, advantageously, an additive manufacturing method or selective powder fusion consisting of producing complex three-dimensional parts by fusing layers of powder.

[0098] Various additive manufacturing techniques are conceivable. In the present invention, additive manufacturing can be selected from the group comprising: - selective laser melting, also designated by the acronym "SLM" for "Selective Laser Melting" in English, - electron beam fusion, also known by the acronym “EBM” for “Electron Beam Melting” in English, - direct additive laser construction, also referred to by the acronym "CLAD" for "Construction Laser Additive Direct" in English, - electron beam additive manufacturing, also designated by the acronym "EBAM" for "Electron Beam Additive Manufacturing" in English, - laser metal deposition, also known by the acronym “LMD” for “Laser Metal Deposition” in English, - the binder jetting process, also known as “Binder Jetting” in English, or - selective laser sintering, also known by the acronym “SLS” for “Selective Laser Sintering” in English.

[0099] Advantageously, but not limitatively, the manufacturing method 100 is carried out by an additive manufacturing installation, not shown.

[0100] Such an additive manufacturing installation comprises, for example, at least one first supply tank containing a first powder, in particular the first material, and at least one member for depositing the first powder from the first supply tank onto a manufacturing support.

[0101] During the production step 110 of the electric machine rotor, layers of first powder are successively spread on the manufacturing support of the additive manufacturing installation.

[0102] Each layer of first powder of the first material, in particular magnetic, is scanned by an energy generating element, such as a laser, melting the first powder constituting the layer so as to form a solidified portion of the rotor 1 which will be covered by another layer of first powder of the first material.

[0103] The manufacturing support moves in a manufacturing enclosure as the rotor 1 is formed.

[0104] The body of revolution 2 is formed layer by layer, by means of an additive manufacturing process from the first material, in particular in powder form.

[0105] As previously stated, the body of revolution 2 is made so as to comprise notches 5 extending in directions parallel to the axis of revolution A, which are distributed around the axis of revolution A and which open onto the radially external surface 6 of the body of revolution 2.

[0106] During the forming step 110, the notches 5 are formed simultaneously in the powder layers of the first material.

[0107] The successive layers of the first material are arranged in a manufacturing direction. The manufacturing direction is advantageously parallel to the axis of revolution A. Alternatively, the manufacturing direction may be perpendicular to the axis of revolution A. Generally, the manufacturing direction may be oriented at an angle of inclination, non-zero and different from 90°, with the axis of revolution A.

[0108] The first material comprises steel or a steel alloy.

[0109] In particular, but not limited to, the steel alloy may be of the iron-cobalt (FeCo) type or of the iron-silicon (FeSi) type.

[0110] In addition, the steel may be a 17-4 PH steel, having ferromagnetic properties. In particular, such a type of steel has a relative magnetic permeability greater than or equal to 1000, making it possible to optimize the passage of the magnetic flux within the body of revolution 2. Such a steel also has good mechanical properties.

[0111] The manufacturing method 100 comprises a filling step 120, during which notches 5 are filled by shape complementarity with the inserts 3, layer by layer, by means of the additive manufacturing method from the second material, in particular non-magnetic, in particular in powder form.

[0112] According to various modes of relationship of the manufacturing method 100, the filling step 120 can be subsequent to the formation step 110, as represented in [Fig.5], or simultaneous with the formation step 110.

[0113] Thus, according to one embodiment, the body of revolution 2 and the inserts 3 can be manufactured simultaneously and during the same steps of the manufacturing method according to the invention.

[0114] Alternatively, according to another embodiment, the inserts 3 can be manufactured after the body of revolution 2 and during separate steps of the manufacturing method 100 according to the invention.

[0115] According to a specific embodiment, the layers of the first material, in particular magnetic, and of the second material, in particular non-magnetic, can be arranged in the same plane.

[0116] In practice, a layer of the first material is arranged on the manufacturing support. A layer of the second material is then arranged at the location forming a notch portion in the layer of the first material.

[0117] Alternatively, the layers of the first material, in particular magnetic, and the layers of the second material, in particular non-magnetic, are arranged at the same time on the manufacturing support.

[0118] Alternatively, the layers of the first material, in particular magnetic, and the layers of the second material, in particular non-magnetic, are arranged one after the other, layer by layer on the manufacturing support.

[0119] The layers of the first material and the second material are melted by the energy generating element, solidified and then covered by other layers of the first material and / or the second material and repeated multiple times to form the rotor 1 of the electric machine according to the invention.

[0120] The forming step 110 and the filling step 120 are repeated until the rotor 1 is completely formed.

[0121] In this context, the additive manufacturing installation comprises a second reservoir intended to contain the powder of the second material, in particular non-magnetic. The powder of the second material is applied, in particular advantageously, by another deposition member connected to the second reservoir for supplying the powder of the second material.

[0122] Alternatively, the first material, in particular magnetic, and the second material, in particular non-magnetic, are applied by the same deposition member.

[0123] Examples of additive manufacturing installations for depositing layers of powder of different materials are marketed, for example, by the company Aerosint or the company Grid Logic.

[0124] The second material, in particular non-magnetic, may comprise a steel or a steel alloy. Advantageously, but not limitingly, the steel is chosen from 316L steel or 304 steel.

[0125] In particular, the steel may be an austenitic steel. Indeed, such a type of steel has good mechanical resistance.

[0126] Furthermore, 316L steel has very low magnetic permeability (close to that of air).

[0127] The inserts 3 made of the second material, in particular non-magnetic steel, completely fill the notches 5 and cause the penetration of the magnetic flux into the body of revolution 2.

[0128] In this way, the manufacturing method 100 by additive manufacturing makes it possible to obtain a rotor 1, massive, single-piece and compact, made of the first material, the purpose of which is to guide the magnetic flux within bodies of revolution 2, and of the second material, in which the magnetic flux does not propagate.

[0129] The second material is intended to provide very good mechanical strength. In addition, the second material is compatible for steel / steel co-manufacturing. With such robustness, the rotor 1 can be driven at high speed.

[0130] The inserts 3 in the notches 5 make the induced currents penetrate further towards the center of the body of revolution 2 and avoid air losses given that the external peripheral surface of the electric machine rotor is smooth.

[0131] This also has the consequence of better distributing the currents induced in the body of revolution 2 of the rotor 1, in particular in the bars 12 of the cage 12.

[0132] [Fig.6] is a variant of the flowchart of the manufacturing process of [Fig.5]

[0133] In the context of a rotor 1 of an electric machine equipped with a cage 10 and produced according to the manufacturing method 100 illustrated in [Fig.6], the inserts 3 are formed so as to comprise recesses 11.

[0134] According to various modes of relationship of the manufacturing method 100, the filling step 120 can be subsequent to the formation step 110, as represented in [Fig.6], or simultaneous with the formation step 110.

[0135] Thus, according to one embodiment, during the filling step 120, the recesses 11 and the inserts 3 can be formed simultaneously in the layers of powder of the second material, in particular non-magnetic.

[0136] Alternatively, according to another embodiment, during the filling step 120, the inserts 3 can be formed after the body of revolution 2 and during separate steps of the manufacturing method 100 according to the invention.

[0137] In particular, spaces may be left empty in each layer of powder of the second material intended to form a portion of insert 3a.

[0138] By successive layers, the recess 11 is thus created, extending along the axis of revolution A and crossing the insert 3 on either side.

[0139] The manufacturing method 100 comprises a step of producing bars 130, during which the bars 12 intended to be integrated respectively into a recess 11 are produced.

[0140] According to various embodiments of the manufacturing method 100, the step of producing bars 130 can be simultaneous with the forming step 110 and / or the filling step 120, or subsequent to the forming step 110 and / or the filling step 120, as shown in [Fig.6].

[0141] The bars 12 are made of a third material, in particular non-magnetic, notably different from the second material. Advantageously, but not limitingly, the third material comprises copper, aluminum, a copper alloy, an aluminum alloy and / or a mixture thereof.

[0142] According to an exemplary embodiment, the bars 12 are produced, layer by layer, by additive manufacturing and independently of the body of revolution 2 and the inserts 3.

[0143] According to another exemplary embodiment, the bars 12 are produced, layer by layer, by additive manufacturing and simultaneously with the body of revolution 2 and the inserts 3.

[0144] Advantageously, the bars 12 are produced by the same additive manufacturing process. In particular, the additive manufacturing installation comprises a third reservoir for supplying powder of the third material, in particular non-magnetic, and a deposition member connected to this third reservoir.

[0145] Once powder layers of the first material and second material are arranged in the required shape, a powder layer of the third material is applied to the manufacturing support at the spaces drawn in the powder layers of the first material and the second material intended to form recess portions.

[0146] Alternatively, the layer of the first material, the layer of the second material and the layer of the third material are arranged in the required shape at the same time.

[0147] The layer of the first material, the layer of the second material and the layer of the third material are melted by a power generating element, solidified and then covered by other layers of the first material, the second material and the third material, and repeated multiple times to form the rotor 1 of the electric machine according to the invention.

[0148] The forming step 110, the filling step 120 and the bar-making step 130 are repeated until the rotor 1 is completely formed.

[0149] The additive manufacturing of at least a portion of the cage 10 allows a saving of time in the manufacturing and in the assembly of the rotor 1 of the electric machine.

[0150] Furthermore, the rotor 1 of the electric machine according to the invention is very robust and can be driven at very high rotational speeds.

[0151] According to another exemplary embodiment, the bars 12 are produced by a casting, rolling, forging and / or machining process. In such a case, the bars 12 are each manufactured separately from the other parts of the rotor 1 and are then inserted into each recess 11.

[0152] The bars 12 can be, for example, introduced from the first end 2a, respectively the second end 2b, of the body of revolution 2, slid inside the recesses 11 and / or the inserts 3 and up to the second end, respectively the first end 2a, of the body of revolution 2.

[0153] In such an embodiment, the bars 12 are then fixed inside the recesses 11 using the plates 13 then positioned subsequently.

[0154] The bars 12 are thus trapped in the recesses 11 and held by the plates 13. The mechanical play between the bars 12 and the recesses 11 to promote sliding is advantageously very reduced so that the cage 10 cannot move.

[0155] The manufacturing method 100 comprises a step of producing plates 140, during which the plates 13 intended to be connected to the longitudinal bars 12 are produced, in particular in the third material, in particular non-magnetic.

[0156] The plates 13 are arranged at the first end 2a and at the second end 2b of the body of revolution 2. The plates 13 are in particular produced, layer by layer, by the additive manufacturing process.

[0157] According to various modes of relationship of the manufacturing method 100, the step of producing plates 140 can be simultaneous with the forming step 110, the filling step 120, and / or the step of producing bars 130, or subsequent to the forming step 110, the filling step 120 and / or the step of producing bars 130.

[0158] Advantageously, but not limitingly, the layers of powder of the third material intended to form the plates 13 are arranged concomitantly with the layers of powder intended to form the bars 12. This makes it possible to reduce the manufacturing time as well as the manufacturing and / or assembly of the rotor 1 of the electric machine.

[0159] Alternatively, the plates 13 are produced by a casting or forging process. In such a case, the manufacturing method 100 comprises a positioning step, during which the plates 13 are arranged at the first end 2a and at the second end 2b of the body of revolution 2.

[0160] In such a configuration, the plates 13 are fixed to the bars 12 produced by casting or forging. The fixings between the plates 13 and the bars 12 can advantageously be produced by welding or brazing.

[0161] The additive manufacturing of the inserts 3 which form bridges in such an embodiment ensures a robust connection with the cage 10 and the body of revolution 2.

[0162] The induced currents are better distributed in the body of revolution 2 of the rotor 1 and in particular in the bars 12 of the rotor 1 of the electric machine equipped with the cage 10.

[0163] In this way, the additive manufacturing of the body of revolution 2, the inserts 3 and / or bars 12 makes it possible to obtain a robust electric machine rotor 1, with a smooth external peripheral surface eliminating air losses and a high-performance magnetic circuit which generates a high torque, capable of driving the rotation of the electric machine rotor 1.

[0164] In addition, with an integrated cage 10, the robustness of the rotor 1 of the electric machine obtained by additive manufacturing is preserved and the presence of the cage allows to improve electrical conductivity and efficiency.

Claims

Claims

1. Rotor (1) of an electric machine comprising: - a single-piece body of revolution (2) with an axis of revolution (A) made of a first material, in particular magnetic, and comprising at least one notch (5) extending along the axis of revolution (A), and - at least one insert (3), in particular longitudinal, made of a second material, in particular non-magnetic, capable of filling the notch (5) by complementarity of shape, characterized in that the insert (3) is securely connected in the notch (5).

2. Rotor (1) of an electric machine according to claim 1, characterized in that the notch (5) opens onto a radially external surface (6) of the body of revolution (2).

3. Rotor (1) of an electric machine according to claim 1 or 2, characterized in that the body of revolution (2) comprising the insert (3) inserted into the notch (5) has a constant radial section along the axis of revolution (A).

4. Rotor (1) of an electric machine according to claim 1 or 2, characterized in that the insert (3) comprises a recess (11) extending along the axis of revolution and passing through the insert (3) on either side along the axis of revolution (A).

5. Rotor (1) of an electric machine according to claim 4, characterized in that it comprises at least one bar (12) inserted in the recess (11) and having a length along the axis of revolution (A) substantially equal to a length of the recess (11).

6. Rotor (1) of an electric machine according to claim 5, characterized in that an insert portion (3a) is arranged radially outside the bar (12) so as to form a bridge.

7. Rotor (1) of an electric machine according to claim 5 or 6, characterized in that it comprises two plates (13) arranged respectively at a first end (2a) and at a second end (2b) of the body of revolution (2) and connected by the bar (12),

8. Rotor (1) of an electric machine according to any one of claims 5 to 7, characterized in that the bar (12) is made of a third material, in particular non-magnetic, in particular different from the second material.

9. Rotor (1) of an electric machine according to claims 7 and 8, characterized in that the plates (13) are made in the third material.

10. Rotor (1) of an electric machine according to any one of the preceding claims, characterized in that the body of revolution (2) comprises a plurality of notches (5) distributed around the axis of revolution (A).

11. Method (100) for manufacturing a rotor (1) of an electric machine, comprising at least: - a production step (110), during which a single-piece body of revolution (2) with an axis of revolution (A), comprising at least one notch (5) extending along the axis of revolution (A) and opening onto a radially external surface (6) of the body of revolution (2), is produced from a first material, in particular magnetic, in particular in powder form, and - a filling step (120), during which the notch (5) is filled by form-fitting with a longitudinal insert (3), formed from a second material, in particular non-magnetic, in particular in powder form.

12. Manufacturing method (100) according to claim 11, characterized in that a recess (11) is formed in the insert (3) during the filling step (120).

13. Manufacturing method (100) according to claim 11 or 12, characterized in that it comprises a step of producing bars (130), during which at least one bar (12) intended to be integrated into the recess (11) is produced from a third material, in particular non-magnetic, in particular different from the second material.

14. Manufacturing method (100) according to claim 13, characterized in that the bar (12) is produced layer by layer by an additive manufacturing method or by a molding, rolling, forging and / or machining method.

15. Manufacturing method (100) according to any one of claims 11 to 14, characterized in that it comprises a step of producing plates (140), during which plates (13), intended to be arranged respectively at a first end (2a) and at a second end (2b) of the body of revolution (2) and to be connected by the bar (12), are produced, in particular from the third material.

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