Winded rotor for an electric motor with a cooling circuit

Description

[0001] The invention relates to a wound rotor for an electric motor arranged to allow better evacuation of the heat generated during its operation. The invention also relates to an electric motor comprising such a wound rotor.

[0002] Generally speaking, current electric motors comprise a rotor secured to a shaft and a stator which surrounds the rotor. The stator is mounted in a casing which comprises bearings for the rotational mounting of the shaft. The stator generally comprises a body consisting of a stack of sheets forming a crown, the inner face of which is provided with teeth delimiting two by two a plurality of notches open towards the inside of the stator body and intended to receive phase windings. These phase windings pass through the notches of the stator body and form buns projecting on either side of the stator body. The phase windings may for example consist of a plurality of U-shaped conductor segments, the free ends of two adjacent segments being connected together by welding. The rotor may be of several types.A possible configuration consists of a wound rotor consisting of a stack of laminations mounted coaxially on the rotor shaft, said stack of laminations having several pairs of poles, each pole being spaced from an adjacent pole by an interpolar space, and windings surrounding the poles of the stack of laminations and being connected to a collector generally formed by copper rings coming opposite brushes for supplying the windings.

[0003] During motor operation, the currents flowing through the stator phase windings and rotor windings generate significant heat that must be removed. There are currently several solutions for cooling the motor. One of these solutions is to spray a cooling fluid inside the motor so that it is in contact with the stator phase windings and rotor windings. However, this solution has the disadvantage of not spraying the cooling fluid directly onto the stator phase windings and rotor windings, which generates excess consumption of cooling fluid to allow proper removal of the heat generated by these phase windings and windings.

[0004] EP 3 633 825 A1 relates to a wound rotor comprising pipes for circulating a cooling fluid arranged either in contact with the insulators of the windings or inside the spaces between several windings.

[0005] The invention therefore aims to propose a wound rotor and an electric motor comprising such a rotor arranged to allow better evacuation of the heat generated during its operation, by cooling the rotor windings and / or the stator coils as closely as possible, and not having the drawbacks of the existing solutions described previously.

[0006] To this end, the invention relates to a wound rotor for an electric motor comprising: a rotor shaft rotatably mounted about an axis;a lamination pack mounted coaxially on the rotor shaft, said lamination pack extending between a front lateral face and a rear lateral face and having an alternation of poles and interpolar spaces, lamination pack insulators arranged so as to at least partially cover external surfaces of the lamination pack defining the interpolar spaces, said lamination pack insulators and said external surfaces being configured to form, between them, longitudinal fluid circulation channels, said longitudinal fluid circulation channels extending axially along the lamination pack such that they open, at one of their ends, at the front lateral face of said lamination pack and, at another of their ends, at the rear lateral face of said lamination pack, said longitudinal fluid circulation channels being configured to allow the circulation of a cooling fluid;a front winding flange and a rear winding flange mounted coaxially on the rotor shaft and arranged axially on either side of the lamination pack so as to be contiguous respectively to the front and rear lateral faces of the lamination pack, said front and rear winding flanges each having a series of T-shaped radial branches, each of said radial branches being axially aligned with one of the poles of the lamination pack and preferably having a profile similar or identical to that of said pole in a plane perpendicular to the axis of the shaft; windings partially surrounding the lamination pack insulators and the radial branches of the front and rear winding flanges; ; in which the shaft is provided with at least one first internal channel for circulating a cooling fluid, called the fluid inlet channel, and at least one second internal channel for circulating a cooling fluid, called the fluid outlet channel, and in that the front winding flange, respectively the rear winding flange, is crossed by at least one front, respectively rear connecting channel, inside which a cooling fluid can circulate, said at least one front, respectively rear connecting channel, being in fluid communication with one of said fluid inlet and fluid outlet channels and with at least one of said longitudinal fluid circulation channels.

[0007] Thus configured, the rotor of the invention can advantageously be cooled by means of a cooling fluid circulating successively inside the rotor shaft via the fluid inlet channel, then inside one of the winding flanges via the front or rear connecting channels, then along the stack of laminations via the longitudinal fluid circulation channels, then inside the other winding flange via the rear or front connecting channels, to finally exit the rotor via the fluid outlet channel, thus allowing good heat removal from the rotor due to the direct contact of the fluid with the stack of laminations.

[0008] The rotor of the invention may also include one or more of the following characteristics: said at least one front connecting channel is in fluid communication with the fluid inlet channel and said at least one rear connecting channel is in fluid communication with the fluid outlet channel, such that a fluid intended for cooling the rotor can circulate in the rotor successively through the fluid inlet channel, then inside the front winding flange through said at least one front connecting channel, then along the stack of sheets through at least one of the longitudinal fluid circulation channels, then inside the rear winding flange through said at least one rear connecting channel, and finally through the fluid outlet channel.the shaft comprises a front end portion and a rear end portion separated from the front end portion by a solid central portion, the front end portion, respectively the rear end portion, being crossed by a central cavity of cylindrical shape, said central cavity forming the fluid inlet channel, respectively the fluid outlet channel, of the shaft, and in that at least one connecting hole oriented radially relative to the axis of the shaft is formed inside the front end portion, respectively the rear end portion, so as to open on one side into the fluid inlet channel, respectively into the fluid outlet channel, and on the other side into said at least one front connecting channel, respectively into said at least one rear connecting channel.said at least one front, respectively rear, connecting channel comprises at least one first section oriented radially relative to the axis of the shaft, at least one second section oriented orthoradially relative to the axis of the shaft, and at least one third section oriented parallel to the axis of the shaft, in which said at least one first section has at least one end adjoining the rotor shaft, in which said at least one second section opens, on one side, onto said at least one first section and, on the other side, onto said at least one third section, and in which said at least one third section has at least one end opening at one of the longitudinal fluid circulation channels. the front, respectively rear, winding flange is crossed by a plurality of front, respectively rear connecting channels, each of said front, respectively rear connecting channels comprises a first section oriented radially relative to the axis of the shaft, several second sections oriented orthoradially relative to the axis of the shaft, and several third sections oriented parallel to the axis of the shaft, in which said first section has at least one end adjoining the rotor shaft, in which each of said second sections opens, on one side, onto the first section and, on the other side, onto one of the third sections, and in which each of said third sections has at least one end opening at one of the longitudinal fluid circulation channels.the third section or each of the third sections has at least one other end opening at an external lateral face of the front, respectively rear, winding flange, which faces the windings. the front, respectively rear, winding flange has an internal lateral face in contact with the front, respectively rear, lateral face of the pack of sheets, said internal lateral face being provided with a cavity in which a cover is housed, said cavity being configured to form at least partially, in combination with said cover, the front, respectively rear, connecting channel(s).the cavity comprises a central portion of annular shape, which extends radially from a hollowed-out central zone of the front, respectively rear winding flange, said central zone being configured to partially house the rotor shaft, and several radial extensions extending radially from said central portion, each of the radial extensions being aligned with one of the radial branches of the front, respectively rear winding flange.the cavity is delimited by a bottom wall and by several side walls oriented perpendicular to said bottom wall, said bottom wall being provided with first grooves oriented radially with respect to the axis of the shaft and second grooves oriented orthoradially with respect to the axis of the shaft, said first and second grooves forming respectively, in combination with corresponding grooves of the cover, the first and second sections of the front, respectively rear connecting channels. several side walls, which are oriented radially with respect to the axis of the shaft, are provided with third grooves oriented parallel to the axis of the shaft, said third grooves forming, in combination with corresponding grooves of the cover, at least part of the third sections of the front, respectively rear connecting channels.the cavity is configured to form housings arranged radially around the central portion, each of the housings having a specific shape and being intended to receive a corresponding connecting element of the cover having a shape complementary to that of said housing, said specific shape and said complementary shape being configured to prevent any relative movement between the cover and the front, respectively rear, winding flange in a radial direction, thus securing the coupling of the cover on the front, respectively rear, winding flange. the housings of the cavity have a dovetail shape. the longitudinal fluid circulation channels are defined at least partially by grooves formed along the external surfaces of the sheet stack which are in contact with the sheet stack insulators.the longitudinal fluid flow channels are defined at least partially by grooves formed along internal surfaces of the lamination pack insulators that are in contact with the lamination pack.

[0009] The invention also relates to an electric motor comprising a wound rotor as defined above.

[0010] The invention will be better understood upon reading the non-limiting description which follows, given with reference to the attached figures. [ Fig. 1 ] is a perspective view of an electric motor equipped with a wound rotor according to the invention, the motor being seen from its front side, [ Fig. 2 ] is a view similar to the figure 1 , the engine being seen from its rear side, [ Fig. 3 ] is a longitudinal sectional view of the engine of the figures 1 et 2 , [ Fig. 4 ] is a perspective view of the wound rotor equipping the motor of the figures 1 et 2 , [ Fig. 5a ] is a perspective view of the sheet metal stack covered with sheet metal stack insulators equipping the rotor of the figure 4 , [ Fig. 5b ] is a view similar to the figure 5a according to a first variant embodiment of the sheet metal pack and the sheet metal pack insulators, [ Fig. 5c ] is a view similar to the figure 5a according to a second variant of embodiment of the sheet metal pack insulators, [ Fig. 6 ] is a longitudinal sectional and perspective view of the rotor of the figure 4 , the sheet metal pack and the windings having been removed, [ Fig. 7 ] is an axial view of one of the winding flanges equipping the rotor of the figure 4 , [ Fig. 8 ] is a perspective view of the internal face of the flange shown in the figure 7 , the cover having been removed, [ Fig. 9 ] is a perspective view of the external face of the flange shown in the figure 7 , the cover having been removed, [ Fig. 10 ] is a perspective view of the external face of the cover of the flange shown in the figure 7 , [ Fig. 11 ] is a perspective view of the inner face of the cover of the flange shown in the figure 7 .

[0011] Throughout the description and in the claims, the terms "axial" and "radial" and their derivatives are defined relative to the axis of rotation of the rotor. Thus, an axial orientation refers to an orientation parallel to the axis of rotation of the rotor and a radial orientation refers to an orientation perpendicular to the axis of rotation of the rotor. Furthermore, by convention, the terms "front" and "rear" refer to separate positions along the axis of rotation of the rotor. In particular, the "front" end of the rotor shaft corresponds to the end of the shaft on which a pulley, a pinion, a spline intended to transmit the rotational movement of the rotor to any other similar motion transmission device can be fixed.

[0012] THE figures 1 à 3 represent an electric motor 1 according to the invention comprising two bearings, respectively a front bearing 2 in the form of a bell and a rear bearing 3 in the form of a disc, connected together by means of screws 4, the front bearing 2 housing a rotor 10 integral in rotation with a shaft 12 and an annular stator 11 which surrounds the rotor 10 coaxially with the shaft 12. As represented in figure 3 , the front and rear bearings 2, 3 each centrally carry a ball bearing respectively 5 and 6 for the rotational mounting of the shaft 12. Ball ends 13 project axially on either side of the stator 11 and are housed in the intermediate space separating the stator 11 from the respective bearings 2, 3. The front and rear bearings 2, 3 will advantageously be made of metal. In the configuration shown, the front bearing 2 is provided with a series of openings 7 which will be used for the evacuation of a cooling fluid to the outside of the motor 1. This cooling fluid will be able to penetrate inside the internal space defined by the front and rear bearings 2, 3 via a first internal circulation channel 124, called the fluid inlet channel, and a second internal channel 126 for circulation of a cooling fluid, called the fluid outlet channel.The fluid inlet and outlet channels 124, 126 are respectively defined by blind holes aligned along the axis X of the shaft 12 and formed through front 121 and rear 123 end portions of the shaft 12, said end portions 121, 123 being separated by a solid central portion 122.

[0013] Rotor 10 equipping motor 1 of the figures 1 à 3 is represented on the figures 4 And 6 The rotor 10 is of the wound type and notably comprises a pack of sheets 14 (shown in the figure 5a ) formed from an axial stack of laminations which extend in a radial plane perpendicular to the axis X of the shaft 12. The lamination pack 14 is mounted coaxially on the shaft 12. The shaft 12 may be force-fitted inside a central opening of the lamination pack 14 so as to connect the rotor body in rotation with the shaft 12. The lamination pack 14 extends between a front lateral face 143 and a rear lateral face 144 and has a circumferential alternation of poles 141 and interpolar spaces 142. The interpolar spaces 142 extend between two adjacent poles 141 and form recesses extending over the entire length of the lamination pack 14, between the two adjacent poles 141.

[0014] In the configuration shown, the poles 141 are 6 in number and are arranged around the shaft 12 so as to be regularly spaced, two adjacent poles 141 being spaced by an angle of approximately 60°. The poles 141 extend radially from an annular portion 146 of the lamination pack 14 provided with a central opening 149 configured to partially house the shaft 12 of the rotor. Each pole 141 has a T-shaped profile in a plane orthogonal to the axis X and has, in the radial direction, a narrow section extended by a widened section of domed shape. The widened domed section has an external peripheral surface 147 which, in the mounted position of the rotor 10, faces an internal peripheral surface 111 of the stator 11 (see figure 3 ), said external peripheral surface 147 being spaced from said internal peripheral surface 111 by a distance less than 1 mm.

[0015] Each pole 141 receives a longitudinal winding 16 intended to generate a magnetic flux in the rotor pole. The windings 16 are wound around the poles 141 and around front 15 and rear 15' winding flanges which axially enclose the lamination pack 14. These winding flanges 15, 15' are mounted coaxially on the shaft 12 of the rotor and arranged axially on either side of the lamination pack 14 so as to be contiguous respectively to the front and rear lateral faces 143, 144 of the lamination pack 14.

[0016] As shown in the figure 5a , lamination pack insulators 17 are arranged to cover the outer lateral surfaces 145 of the lamination pack 14 which define the interpolar spaces 142. These lamination pack insulators 17 are configured to prevent the establishment of a short circuit between the windings 16 and the poles 141 of the lamination pack. The lamination pack insulators 17 are usually made from dielectric materials, for example based on plastic. Each lamination pack insulator 17 has an inner face 171 in contact with an outer lateral surface 145 of the lamination pack 14 and an outer face 172 which is opposite the inner face 171, said inner and outer faces 171, 172 extending axially between a front end edge 173 and a rear end edge 174 (see figure 6 ).

[0017] The sheet metal pack insulators 17 and the outer side surfaces 145 of the sheet metal pack 14 are configured to form longitudinal fluid circulation channels 18, which extend axially along the sheet metal pack 14 (see figure 3 ) such that they open, at one of their ends, at the front lateral face 143 of the stack of sheets 14 and, at another of their ends, at the rear lateral face 144 of said stack of sheets 14. These longitudinal channels 18 will thus make it possible to circulate a cooling fluid along the stack of sheets 14, thereby evacuating the heat stored by this stack of sheets during operation of the engine.

[0018] These longitudinal fluid circulation channels 18 are defined, in the embodiment variant shown in the figure 5a , by the combination of grooves 148 formed axially along the external lateral surfaces 145 of the sheet metal pack 14 and grooves 178 formed axially along the internal faces 171 of the sheet metal pack insulators 17, said grooves 148, 178 facing each other in pairs. In this variant, the longitudinal fluid circulation channels 18 are six in number for each of the poles 141, said channels 18 being arranged angularly around the shaft 12 in several groups of three channels aligned in the same radial direction.

[0019] This embodiment variant is obviously only a non-limiting example for the invention. It will be possible in particular to reduce or increase the number of channels 18 per notch and / or to form the channels 18 solely by means of grooves 148 formed along the external lateral surfaces 145 of the sheet stack 14 or solely by means of grooves 178 formed along the internal faces 171 of the sheet stack insulators 17.

[0020] Thus, in the embodiment shown in the figure 5b , the channels 18 are two in number per notch and are defined solely by means of grooves 178 formed axially along the internal faces 171 of the sheet metal pack insulators 17, whereas in the embodiment variant shown in the figure 5c , the channels 18 are still six in number per notch but the channels 18 are defined here only by means of grooves 148 formed along the external lateral surfaces 145 of the sheet metal pack 14.

[0021] In reference to the figure 7 , the internal lateral face 153 of the front winding flange 15 is shown, which is oriented towards the pack of sheets 14. The front and rear winding flanges 15 and 15' having the same profile, the structural details given below with reference to the figure 7 also apply to the rear winding flange 15'. The front winding flange 15 has a series of T-shaped radial branches 151. Each of the radial branches 151 is axially aligned with one of the poles 141 of the lamination pack 14 and has, in the preferred configuration shown in the figure 4 , a profile similar or identical to that of the pole 141 with which it is aligned in a plane orthogonal to the axis X of the shaft 12. Thus, each radial branch 151 has, in the radial direction, a narrow section 152 extended by a widened section 154 of curved shape.

[0022] The front winding flange 15 is furthermore provided with a central cavity 21 in which a cover 22 is housed. As described in detail in the following paragraphs, the cavity 21 and the cover 22 are configured to form at least one fluid connection channel, and preferably a plurality of fluid connection channels, inside the front winding flange 15, this or these fluid connection channels communicating fluidically with the fluid inlet channel 124 of the shaft 12 and with the longitudinal fluid circulation channels 18 passing through the stack of sheets 14. This or these fluid connection channels may advantageously open at fluid outlet openings located at the external periphery of said front winding flange 15 and oriented towards the windings 16.Similarly, the rear winding flange 15' is provided with a central cavity 21 in which a cover 22 is housed, said cavity 21 and said cover 22 being configured to form at least one fluid connection channel, and preferably a plurality of fluid connection channels, inside the rear winding flange 15', this or these fluid connection channels communicating fluidically with the fluid outlet channel 126 of the shaft 12 and with the longitudinal channels 18 for fluid circulation passing through the stack of sheets 14. This or these fluid connection channels will advantageously open at fluid outlet openings located at the external periphery of said rear winding flange 15' and oriented towards the windings 16.In the remainder of the description, and by convention, the fluid connection channel(s) formed inside the front winding flange 15 will be called front connection channels and the fluid connection channel(s) formed inside the rear winding flange 15' will be called rear connection channels.

[0023] So, as shown in the figure 6 , a cooling fluid F supplied from the fluid inlet channel 124 may circulate inside the front winding flange 15 via said front connecting channel(s), then may either be projected towards the windings 16 surrounding the front winding flange 15, thus allowing effective cooling of said windings 16, or circulate along the sheet metal pack 14 through at least one of the longitudinal fluid circulation channels 18, then may circulate inside the rear winding flange 15' through said rear connecting channel(s), and finally may either be projected towards the windings 16 surrounding the rear winding flange 15', or exit the motor through the fluid outlet channel 126.

[0024] The particular configuration of the front winding flange 15 and its associated cover 22 as shown in the figure 6 is described in detail below, with reference to the figures 8 à 11 . Since the rear winding flange 15' has a structure substantially identical to that of the front winding flange 15, the technical details given below will apply in a similar manner to the rear winding flange 15' and its associated cover.

[0025] Thus, the front winding flange 15 substantially defines a star-shaped structure comprising a central portion 156 of hexagonal shape extended on each of its sides by the T-shaped radial branches 151. The central portion 156 has a hollowed-out central zone 157, which is configured to partially house the shaft 12 of the rotor.

[0026] The front winding flange 15 has an internal side face 153 (visible on the figure 8 ) and an external lateral face 155 (visible on the figure 9 ). The internal lateral face 153 is in contact with the front lateral face 143 of the sheet metal pack 14 and the external lateral face 155 is oriented towards the front bearing 2.

[0027] The external lateral face 155 is configured to define between the enlarged section 154 of each radial branch 151 and the central part 156 a radial space allowing the windings 16 to be housed.

[0028] The internal lateral face 153, which is predominantly flat, is provided with a central cavity 21 which extends radially from the central zone 157 towards the external peripheral faces 158 of the front winding flange 15, which are defined by the curved external sides of the enlarged sections 154 of the radial branches 151.

[0029] The cavity 21 comprises in particular a central portion 21a of annular shape, which adjoins the central zone 157, and several radial extensions 21b extending radially from said central portion 21a. Each of the radial extensions 21b is aligned with one of the radial branches 151 of the front winding flange 15 and comprises a narrow portion 21b1 extended radially by a widened portion 21b2.

[0030] The cavity 21 is in particular delimited by a bottom wall 211, by several side walls 212 oriented radially with respect to the axis X, and by several side walls 213 oriented orthoradially with respect to the axis X.

[0031] The bottom wall 211 is provided with first grooves 214 oriented radially relative to the axis X and second grooves 215 oriented orthoradially relative to the axis X. The side walls 212 are, for their part, provided with third grooves 218 oriented parallel to the axis X, each of the third grooves 218 opening, at a first end, onto a first axial fluid outlet opening 219 (see figures 6 And 7 ) located on the internal lateral face 153 of the winding flange 15 and opening onto one of the longitudinal channels 18 of the sheet metal pack 14, and, at a second end, onto a second axial fluid outlet opening 220 located on the external lateral face 155 of the winding flange 15, at the level of the radial space which serves as housing for the windings 16.

[0032] In the configuration shown, the first grooves 214 are 6 in number, each of the first grooves 214 being formed through the central portion 21a and the narrow and widened portions of one of the radial extensions 21b and extending from a first end adjoining the central zone 157 to a second end located at one of the side walls 213 of the cavity 21.

[0033] In the configuration shown, the second grooves 215 are 36 in number, each of the second grooves 215 being formed through the widened portion 21b2 of one of the radial extensions 21b and extending from a first end adjoining one of the first grooves 214 to a second end located at one of the side walls 212 of the cavity 21. This second end opens onto one of the third grooves 218.

[0034] The first, second and third grooves 214, 215 and 218 are configured to form, in combination with corresponding grooves of the front cover 22, the front connecting channels of the front winding flange 15.

[0035] For this purpose, and as shown on the figures 10 And 11 , the cover 22 has a shape complementary to the cavity 21 of the winding flange 15.

[0036] The cover 22 comprises in particular a central part 22a of annular shape intended to fit inside the central part 21a of the cavity 21. In order to secure the coupling of the cover 22 on the winding flange 15, the cover 22 is advantageously provided with dovetail ribs 226 forming projections at the external periphery of the central part 22a of the cover 22, said ribs 226 having a shape complementary to that of corresponding hollow shapes 216 of the winding flange 15 (see figure 8 ), each of said hollow shapes 216 being intended to house one of said ribs 226.

[0037] The cover 22 also comprises several radial extensions 22b extending radially from the central portion 22a. Each of the radial extensions 22b comprises a narrow portion 22b1 extended radially by a widened portion 22b2. The radial extensions 22b are intended to fit inside the radial extensions 21b of the cavity 21.

[0038] The cover 22 is in particular delimited by an internal wall 221, which is in contact with the bottom wall 211 of the cavity 21, by an external wall 229, which is opposite the internal wall 221, by several side walls 222, which are in contact with the side walls 212 of the cavity 21, and by several side walls 223, which are in contact with the side walls 213 of the cavity 21.

[0039] The inner wall 221 is provided with first grooves 224 oriented radially with respect to the axis X and forming, in combination with the first grooves 214 of the cavity 21, first sections of the front connecting channels. Each of said first sections opens, at its proximal end, onto a through hole 125 formed inside the shaft 12 and oriented radially with respect to the axis X (see figure 3), said holes 125 being formed inside the front end portion 121 so as to open, on one side, into the fluid inlet channel 124 and, on the other side, at the peripheral wall of the shaft 12. Similarly, several holes 127 oriented radially relative to the axis X of the shaft 12 are formed inside the rear end portion 123 so as to open, on one side, into the fluid outlet channel 126 and, on the other side, at the peripheral wall of the shaft. These holes 125, 127 will make it possible to supply fluid to the front and rear connection channels of the front and rear winding flanges 15, 15' respectively.

[0040] The inner wall 221 is also provided with second grooves 225 oriented orthoradially relative to the X axis and forming, in combination with the second grooves 215 of the cavity 21, second sections of the front or rear connecting channels, said second sections being in fluid communication with said first sections.

[0041] The side walls 222 of the cover 22 are, for their part, provided with third grooves 228 oriented parallel to the axis X and forming, in combination with the third grooves 218 of the cavity 21, third sections of the front or rear connecting channels, said third sections being in fluid communication with said second sections. Each of said third sections thus opens, on one side, onto the first axial outlet opening 219 and, on the other side, onto the second axial outlet opening 220.

[0042] Thus configured, the rotor 10 and the motor 1 may be cooled by a cooling fluid, such as oil or pressurized air for example, said cooling fluid circulating in the rotor 10 successively through the fluid inlet channel 124, then inside the front winding flange 15 through, successively, the first, second and third sections of the front connecting channels, then between the lamination pack 14 and the lamination pack insulators 17 through the longitudinal channels 18, then inside the rear winding flange 15' through, successively, the third, second and first sections of the rear connecting channels, to finally be expelled from the motor 1 through the fluid outlet channel 126. During its journey inside the rotor 10, the cooling fluid can thus extract part of the heat stored by the lamination pack 14.

[0043] Furthermore, the cooling fluid may also be sprayed onto the windings 16 through the second axial openings 220 so that, once in contact with the windings 16, it can extract part of the heat stored by said windings 16. The cooling fluid thus sprayed then circulates inside the stator 11, before being evacuated from the motor 1 via the openings 7.

[0044] The invention is obviously not limited to the embodiments as described above. In particular, in other embodiments (not shown) of the invention, the front and / or rear winding flanges 15, 15' may also be provided with radial fluid outlet channels opening at radial outlet openings located at the outer periphery of said front and / or rear winding flanges, each of said radial fluid outlet channels being in fluid communication with said front or rear connecting channel(s) and being oriented towards the coil ends protruding at the front or rear of the stator. Furthermore, the presence of a cover 22 housed inside a central cavity 21 of the front winding flange 15, respectively rear 15', is only one possibility for forming the fluid circulation channels.In other embodiments of the invention, it is conceivable not to provide such a cover and such a cavity.

Claims

1. A wound rotor (10) for an electric motor (1) comprising: - a rotor shaft (12) rotatably mounted about an axis (X); - a stack of laminations (14) mounted coaxially on the rotor shaft (12), said stack of laminations (14) extending between a front lateral face (143) and a rear lateral face (144) and having an alternation of poles (141) and interpolar spaces (142), - stack of laminations insulators (17) arranged so as to at least partially cover external surfaces (145) of the stack of laminations (14) defining the interpolar spaces (142), said stack of laminations insulators (17) and said external surfaces (145) being configured to form, therebetween, longitudinal fluid circulation channels (18), said longitudinal fluid circulation channels (18) extending axially along the stack of laminations (14) such that they open, at one of their ends, at the level of the front lateral face (143) of said stack of laminations (14) and, at another of their ends, at the level of the rear lateral face (144) of said stack of laminations (14), said longitudinal fluid circulation channels (18) being configured to allow the circulation of a cooling fluid; - a front winding flange (15) and a rear winding flange (15') mounted coaxially on the rotor shaft (12) and arranged axially on either side of the stack of laminations (14) so as to be contiguous respectively to the front and rear lateral faces (143, 144) of the stack of laminations (14), said front and rear winding flanges (15, 15') each having a series of T-shaped radial branches (151), each of said radial branches (151) being axially aligned with one of the poles (141) of the stack of laminations (14) and preferably having a profile similar or identical to that of said pole (141) in a plane perpendicular to the axis (X) of the shaft; - windings (16) partially surrounding the stack of laminations insulators (17) and the radial branches (151) of the front and rear winding flanges (15, 15'); in which the shaft (12) is provided with at least one first internal channel (124) for circulating a cooling fluid, called the fluid inlet channel, and at least one second internal channel (126) for circulating a cooling fluid, called the fluid outlet channel, and in that the front winding flange (15), respectively the rear winding flange (15'), is crossed by at least one front, respectively rear, connecting channel, inside which a cooling fluid can circulate, said at least one front, respectively rear connecting channel being in fluid communication with one of said fluid inlet (124) and fluid outlet (126) channels and with at least one of said longitudinal fluid circulation channels (18).

2. The wound rotor (10) according to claim 1, characterized in that said at least one front connecting channel is in fluid communication with the fluid inlet channel (124) and said at least one rear connecting channel is in fluid communication with the fluid outlet channel (126), such that a fluid intended for cooling the rotor can circulate in the rotor successively through the fluid inlet channel (124), then inside the front winding flange (15) through said at least one front connecting channel, then along the stack of laminations (14) through at least one of the longitudinal fluid circulation channels (18), then inside the rear winding flange (15') through said at least one rear connecting channel, and finally through the fluid outlet channel (126).

3. The wound rotor (10) according to claim 2, characterized in that the shaft (12) comprises a front end portion (121) and a rear end portion (123) separated from the front end portion (121) by a solid central portion (122), the front end portion (121), respectively the rear end portion (123), being crossed by a central cavity of cylindrical shape, said central cavity forming the fluid inlet channel (124), respectively the fluid outlet channel (126), of the shaft (12), and in that at least one connecting hole (125, 127) oriented radially relative to the axis (X) of the shaft (12) is formed inside the front end portion (121), respectively the rear end portion (123), so as to open on one side into the fluid inlet channel (124), respectively in the fluid outlet channel (126), and on the other side in said at least one front connecting channel, respectively in said at least one rear connecting channel.

4. The wound rotor (10) according to any of the preceding claims, characterized in that said at least one front, respectively rear, connecting channel comprises at least one first section (214, 224) oriented radially relative to the axis (X) of the shaft, at least one second section (215, 225) oriented orthoradially relative to the axis (X) of the shaft, and at least one third section (218, 228) oriented parallel to the axis (X) of the shaft, in which said at least one first section (214, 224) has at least one end adjoining the rotor shaft (12), in which said at least one second section (215, 225) opens, on one side, onto said at least one first section (214, 224) and, on the other side, onto said at least one third section (218, 228), and in which said at least one third section (218, 228) has at least one end opening at one of the longitudinal fluid circulation channels (18).

5. The wound rotor (10) according to any of the preceding claims, characterized in that the front (15), respectively rear (15'), winding flange is crossed by a plurality of front, respectively rear, connecting channels, each of said front, respectively rear, connecting channels comprises a first section (214, 224) oriented radially relative to the axis (X) of the shaft, several second sections (215, 225) oriented orthoradially relative to the axis (X) of the shaft, and several third sections (218, 228) oriented parallel to the axis (X) of the shaft, in which said first section (214, 224) has at least one end adjoining the rotor shaft (14), in which each of said second sections (215, 225) opens, on one side, onto the first section (214, 224) and, on the other side, on one of the third sections (218, 228), and in which each of said third sections (218, 228) has at least one end opening at one of the longitudinal fluid circulation channels (18).

6. The wound rotor (10) according to claim 4 or 5, characterized in that the third section (218, 228) or each of the third sections (218, 228) has at least one other end (220) opening at an external lateral face (155) of the front winding flange (15), respectively rear winding flange (15'), which faces the windings (16).

7. The wound rotor (10) according to any of claims 4 to 6, characterized in that the front winding flange (15), respectively the rear winding flange (15'), has an internal lateral face (153) in contact with the front lateral face (143), respectively with the rear lateral face (144), said internal lateral face (153) being provided with a cavity (21) in which a cover (22) is housed, said cavity (21) being configured to form at least partially, in combination with said cover (22), the front, respectively rear, connecting channel(s).

8. The wound rotor (10) according to claim 7, characterized in that the cavity (21) comprises a central part (21a) of annular shape, which extends radially from a hollowed-out central zone (157) of the front (15), respectively rear (15') winding flange, said central zone (157) being configured to partially house the shaft (12) of the rotor, and several radial extensions (21b) extending radially from said central part (21a), each of the radial extensions (21b) being aligned with one of the radial branches (151) of the front (15), respectively rear (15'), winding flange.

9. The wound rotor (10) according to claim 8, characterized in that the cavity (21) is delimited by a bottom wall (211) and by several lateral walls (212, 213) oriented perpendicular to said bottom wall (211), said bottom wall (211) being provided with first grooves (214) oriented radially relative to the axis (X) of the shaft and second grooves (215) oriented orthoradially relative to the axis (X) of the shaft, said first and second grooves (214, 215) respectively forming, in combination with corresponding grooves (224, 225) of the cover (22), the first and second sections (214, 224, 215, 225) of the front, respectively rear, connecting channels.

10. The wound rotor (10) according to claim 9, characterized in that several lateral walls (212), which are oriented radially with respect to the axis (X) of the shaft, are provided with third grooves (218) oriented parallel to the axis (X) of the shaft, said third grooves (218) forming, in combination with corresponding grooves (228) of the cover (22), at least part of the third sections (218, 228) of the front, respectively rear, connecting channels.

11. The wound rotor (10) according to any of claims 8 to 10, characterized in that the cavity (21) is configured to form housings (216) arranged radially about the central part (21a), each of the housings (216) having a specific shape and being intended to receive a corresponding connecting element (226) of the cover (22) having a shape complementary to that of said housing (216), said specific shape and said complementary shape being configured to prevent any relative displacement between the cover (22) and the front winding flange (15), respectively the rear winding flange (15'), in a radial direction, thus securing the coupling of the cover (22) on the front winding flange (15), respectively the rear winding flange (15').

12. The wound rotor (10) according to claim 11, characterized in that the housings (216) of the cavity (21) have a dovetail shape.

13. The wound rotor (10) according to any of the preceding claims, characterized in that the longitudinal fluid circulation channels (18) are defined at least partially by grooves (148) formed along the outer surfaces (145) of the stack of laminations (14) that are in contact with the stack of laminations insulators (17).

14. The wound rotor (10) according to any of the preceding claims, characterized in that the longitudinal fluid circulation channels (18) are defined at least partially by grooves (178) formed along internal surfaces (171) of the stack of laminations insulators (17) that are in contact with the stack of laminations (14).

15. An electric motor (1) comprising a wound rotor (10) according to any of the preceding claims.