Rotating electric machine

Abstract

Rotating electrical machine Rotating electrical machine (1) comprising: - a rotor (2) extending along a longitudinal axis X, - a stator (3) comprising a stator mass (4) comprising notches (12) closed on the rotor side, the notches receiving electrical conductors (11), the stator mass having at least one longitudinal end (5) projecting axially from the rotor along the longitudinal axis X, - a casing (6) surrounding the rotor and the stator, - at least one half-hoop (9), or even two half-hoops, extending from the longitudinal end of the stator mass projecting axially from the rotor, to insulate the electrical conductors of the stator from the rotor, the half-hoop, or even each half-hoop, being formed from a single piece, the half-hoop coming directly into contact with the casing, and the half-hoop being shrunk into the longitudinal end of the stator mass. Figure for abstract: Fig. 1

Description

Title of the invention: Rotating electric machine Technical field

[0001] The present invention relates to rotating electrical machines and in particular to the stators of such machines. The invention relates more particularly to a stator comprising one or more half-frets, allowing the channeling of a cooling fluid in the machine.

[0002] The machines may be synchronous or asynchronous, with alternating current. They may be traction or propulsion machines for electric motor vehicles (Battery Electric Vehicle) and / or hybrid vehicles (Hybrid Electric Vehicle - Plug-in Hybrid Electric Vehicle), such as individual cars, vans, trucks or buses. The invention also applies to rotating electrical machines for industrial and / or energy production applications, in particular naval, aeronautical or wind power. Prior art

[0003] Cooling the stators of rotating electrical machines is essential for their proper operation. It is known from the prior art to circulate a cooling fluid inside a rotating electrical machine. To ensure direct cooling of the coil heads and / or the ends of the electrical conductors received in slots of the stator, it is known to bathe the coil heads and / or the ends of the electrical conductors in a cooling fluid by pressurizing the area of ​​the coil heads and / or the ends of the electrical conductors and by circulating the cooling fluid axially through the stator mass, for example through the slots.

[0004] To do this, through-fret bands running from one end of the casing to the other can be used, as for example in patent applications US 2023 / 0337126 and US 2022 / 0385133. These through-fret bands, in addition to the assembly and mechanical strength difficulties that they can cause, have the consequence of encroaching on the magnetic air gap, which can reduce the electromagnetic performance of the machine.

[0005] Half-frets can also be used, as for example in application US 2022 / 0385152, which presents a rotating electrical machine comprising half-frets having a radial part and an axial part inserted into each other. The axial wall comprises an insert connecting to the casing, the sealing being ensured by an added seal.

[0006] Application US 2022 / 0385127 discloses a rotating electrical machine comprising half-frets having a radial wall and an axial wall, the axial wall being attached to a rib of the casing by means of an added connecting piece.

[0007] Patent application EP 4 142 118 presents an electric machine comprising two L-shaped plastic half-frets, in contact with a metal ring resting on the casing.

[0008] The use of two half-frets creating annular chambers around the coil heads and / or the ends of the electrical conductors of the stator makes it possible to overcome the reduction in performance caused by the through-fret. However, fixing the half-frets to the stator and possibly to the casing, while ensuring sufficient sealing when pressurizing the annular chambers where the coil heads and / or the ends of the electrical conductors are housed, is complex.

[0009] Patent applications US 2017 / 0271955 and US 2022 / 0302784 describe rotating electrical machines comprising annular covers attached to the stator of the machine, encapsulating the coil heads and / or the ends of the electrical conductors.

[0010] There is therefore a need to find a simple solution to implement, requiring few parts, to ensure direct cooling of the coil heads and / or the ends of the electrical conductors and more broadly of the stator, while guaranteeing good sealing with respect to the rotor. Statement of the invention

[0011] The invention aims to meet this need and has as its subject, according to one of its aspects, a rotating electrical machine comprising: - a rotor extending along a longitudinal axis X, - a stator comprising a stator mass comprising closed notches on the rotor side, the notches receiving electrical conductors, the stator mass having at least one longitudinal end protruding axially from the rotor along the longitudinal axis X, - a casing surrounding the rotor and the stator, - at least one half-hoop, or even two half-hoops, extending from the longitudinal end of the stator mass projecting axially from the rotor, to insulate the electrical conductors of the stator from the rotor, the half-hoop, or even each half-hoop, being formed from a single piece, the half-fret coming into direct contact with the casing, and the half-fret being fretted into the longitudinal end of the stator mass.

[0012] The use of one or two half-frets instead of a through-fret allows the machine air gap to be left free and thus not to reduce the electrical performance. electromagnetic fields of the machine.

[0013] The stator mass having one or two longitudinal ends axially projecting from the rotor along the longitudinal axis X, the stator has an excess length relative to the rotor. The excess length of the stator relative to the rotor makes it possible to accommodate the half-fret(s), in particular by shrink-fitting. The shrink-fitting of the half-fret(s) in the stator mass thus ensures overall sealing. The rotating electrical machine may be devoid of seals in the shrink-fitting zone of a half-fret on the stator mass.

[0014] Choosing one or two half-frets can also help form the winding, with the half-frets acting as a comb for bending the electrical conductors.

[0015] The use of half-frets formed from a single piece in direct contact with the casing contributes to the simplicity of production of the machine according to the invention and makes it possible to limit costs. There is in fact no longer any need to use an additional seal. A half-fret integral with the stator can even help guide the stator in the casing.

[0016] By "coming into direct contact with the casing", it is meant that the half-hoop may have come in one piece with the casing or be in contact, by insertion, fitting or otherwise, with the casing, such as with a groove or a shoulder of the casing for example. The rotating electrical machine is in the invention devoid of connecting parts or linking parts to allow the attachment of the half-hoop to the casing. The rotating electrical machine may be devoid of a seal in the area of ​​attachment of the half-hoop(s) with the casing.

[0017] At least one electrical conductor, or even a majority of the electrical conductors, or even all of the electrical conductors, may be bent, in particular in the shape of a U-shaped pin. Alternatively, at least one electrical conductor, or even a majority of the electrical conductors, or even all of the electrical conductors, may be I-shaped.

[0018] Alternatively, at least one electrical conductor may be wound, so as to form a continuous wire winding.

[0019] The electrical conductors may comprise one or more strands, for example two or three strands.

[0020] An electrical conductor, or even each electrical conductor, may comprise at least one leg, in particular two legs connected by a coil head. The leg, in particular each leg, may comprise a straight portion intended to extend axially along the longitudinal axis X in the notch and at the outlets of the notch on either side of the stator mass.

[0021] The electrical conductor may have a rectangular, square or circular cross-section, this list not being limiting. A strand may have a cross-section transverse rectangular, square or circular in shape, this list not being exhaustive.

[0022] The electrical conductor may be made of metal, in particular copper or aluminum.

[0023] In one embodiment, the machine comprises a single half-hoop. In this embodiment, the half-hoop insulates the coil heads and / or the ends of the electrical conductors from the rotor.

[0024] In another embodiment, the machine comprises two half-hoops. In this embodiment, a first half-hoop insulates the winding heads and / or ends of the electrical conductors from the rotor and a second half-hoop insulates opposite ends of the electrical conductors. In the case of continuous winding, each half-hoop insulates a winding area of ​​the electrical conductors from the rotor.

[0025] Each half-fret may define an annular chamber. An annular chamber may encapsulate the coil heads or ends of the electrical conductors.

[0026] An annular chamber containing the coil heads and / or ends of the electrical conductors may be filled with a cooling fluid, so that the coil heads and / or ends of the electrical conductors are immersed in the fluid, thus ensuring good direct cooling thereof. Generally, the annular chambers may be filled with a cooling fluid, so as to act as cooling chambers.

[0027] The stator mass may comprise at least one axial channel extending parallel to the longitudinal axis X, configured to be traversed by a cooling fluid. By "axial channel" is meant a channel formed in the stator mass distinct from the notches. This or these additional axial channels make it possible to improve the efficiency of the cooling of the stator. They may in particular allow fluid communication between the two annular chambers defined by the half-collars.

[0028] The invention thus contributes to improving the cooling of the machine by increasing the wetted surface and reducing pressure losses.

[0029] The annular chambers can be pressurized. The resulting increase in pressure in the stator makes it possible to increase the threshold for the occurrence of partial discharges and consequently the durability of the insulation system. This proves to be particularly advantageous during a voltage increase, for example for a voltage of 800 V instead of the usual 400 V.

[0030] By "notches closed on the rotor side" is meant that the notches are closed on the side of the bore of the stator in which the rotor is inserted, in other words on the air gap side, in order to isolate the electrical conductors of the stator from the rotor. The notches may have at least one opening opposite the air gap, for example on the side of a yoke of the stator mass. Alternatively, the notches may be completely closed, that is to say not having an opening on the side of the yoke of stator mass

[0031] The presence of closed notches on the rotor side, or even completely closed, allows the cooling fluid, in particular oil, to circulate directly in the notches. The fluid is put under pressure and passes into the notches comprising electrical conductors and at least one free space allowing the oil to pass through. This free space can be on the side of the internal diameter of the stator, which would not be possible with open notches.

[0032] Each longitudinal end of the stator mass may axially extend beyond one end of the rotor along the longitudinal axis X by a non-zero distance d. The distance d may be between 1 mm and 8 mm, or even between 2 mm and 5 mm, being for example of the order of 3 mm.

[0033] The stator mass may be formed from a plurality of layers of laminations. A longitudinal end of the stator mass may be obtained by extending the stator mass by means of additional laminations and / or with solid added parts. The number of additional laminations at a longitudinal end of the stator mass may be between 3 and 40 laminations, or even between 6 and 20 laminations, better still between 8 and 12 laminations.

[0034] At least one half-fret, or even both half-frets, may be made of a non-conductive material, in particular plastic, for example polyethersulfone (PES) or polyetheretherketone (PEEK).

[0035] This makes it possible to improve the resistance to the electric field since there is no need to respect a current path distance from the conductor to the stator mass.

[0036] At least one half-fret, or even both half-frets, may comprise a longitudinal portion. By "longitudinal portion" is meant a portion whose longitudinal cross-section extends parallel to the longitudinal axis X.

[0037] At least one half-fret, or even both half-frets, may be formed solely from a longitudinal portion.

[0038] At least one half-fret, or even both half-frets, may be devoid of a radial portion. By "radial portion" is meant a portion extending in a radial plane relative to the longitudinal axis X.

[0039] At least one half-fret, or even both half-frets, may comprise a longitudinal portion and a radial portion. In one embodiment, each half-fret comprises a longitudinal portion and a radial portion.

[0040] The radial portion of the half-fret can contribute to ensuring electrical insulation between the stator mass and the coil heads and / or ends of the electrical conductors. It also makes it possible to limit the need, or even avoid, to control the axial protrusion of the insulating paper inserted in the notches for insulation purposes, this control being usually imperative in structures known from the prior art.

[0041] The longitudinal portion and the radial portion of at least one half-fret may be arranged in an L-shape when the half-fret is viewed in longitudinal section. In one embodiment, each half-fret is arranged in an L-shape when the half-fret is viewed in longitudinal section.

[0042] The L-shape of a half-hoop provides mechanical support for the stator mass in the axial and radial directions. This reduces the bulging (the separation of the sheets from each other) of the end sheets which can occur when the sheets are assembled together.

[0043] The radial portion of at least one half-fret may be arranged in abutment against an end face of the stator mass. By "end face" of the stator mass is meant one of the two faces of the stator mass extending in a transverse plane perpendicular to the longitudinal axis X.

[0044] In an embodiment where the longitudinal portion and the radial portion of a half-fret are arranged in an L-shape when the half-fret is viewed in longitudinal section, the fact that the radial portion abuts against an end face of the stator mass facilitates the bending of the electrical conductors by acting as a comb and electrically protects the bent areas of the electrical conductors and thus contributes to extending the life of the electrical insulation system.

[0045] The radial portion of the half-fret(s) may be arranged to match the shape of the notches present on the end faces of the stator mass. This configuration allows the electrical conductors of the stator to pass through.

[0046] The longitudinal portion of the half-hoop may extend beyond the radial portion of the half-hoop on the stator mass side by a non-zero distance dL, forming a hooping portion inserted into the stator mass. The distance dL is preferably less than the distance d, so that the hooping portion of the half-hoop does not penetrate into the air gap of the machine, between the rotor and the stator.

[0047] The radial portion of the half-fret may comprise at least one insertion pad. The radial portion may comprise a single insertion pad. Alternatively, it may comprise several insertion pads, for example two or four insertion pads, or even more, for example between 10 and 14, in particular 12 insertion pads.

[0048] The insertion pads may all be equidistant from the longitudinal axis X. They may be equally distributed angularly around the longitudinal axis X.

[0049] The insertion pad(s) may have a circular or oval, or polygonal, in particular square or rectangular, cross-section, this list not being limiting.

[0050] At least one female receiving portion may be arranged on the end face of the stator mass to receive each insertion pad of the half-hoop. The presence of at least one insertion pad and at least one female receiving portion to receive it facilitates the assembly of the half-fret. This can also help ensure the sealing of the structure formed by the half-fret(s) and the stator.

[0051] Each female receiving portion may be formed by a hole in a longitudinal end of the stator mass. In an embodiment where the stator mass is formed from a plurality of layers of laminations and where a longitudinal end of the stator mass is obtained by extending the stator mass by means of additional laminations, at least one female receiving portion may be formed by a hole passing through at least one additional lamination, preferably several additional laminations. The greater the number of additional laminations passed through, the better the retention of the half-collar. The number of laminations passed through is limited by the number of additional laminations.

[0052] The rotor may comprise at least one flange. The longitudinal portion of at least one half-fret, or even both half-frets, may comprise an end that is hooped to the stator and is chamfered, on a face directly facing a flange of the rotor. The presence of chamfers helps to maintain a sufficient distance between the half-frets and the flanges of the rotor.

[0053] The casing may comprise a circumferential portion and two end portions. The longitudinal portion of at least one half-fret may be in contact with an end portion of the casing and / or the radial portion of at least one half-fret may be in contact with the circumferential portion of the casing.

[0054] By "circumferential portion of the casing" is meant a portion of casing having a cross-section perpendicular to the longitudinal axis X of at least partly circular shape. The circumferential portion surrounds the rotor and the stator when the machine is observed along the longitudinal axis X.

[0055] By "end portion of the casing" is meant a portion of casing extending at least partly in a transverse plane perpendicular to the longitudinal axis X. One end portion may close the circumferential portion of the casing on one side, the two end portions may close the circumferential portion of the casing on both sides.

[0056] The casing may comprise at least one groove or at least one shoulder into which a half-hoop is fitted. In an embodiment where the machine comprises two half-hoops, the casing may comprise two grooves or shoulders, into each of which a half-hoop is fitted. The groove(s) may be formed in a single piece in the casing.

[0057] In one embodiment, the circumferential portion of the casing may comprise at least one groove or at least one shoulder into which the radial portion of a half-collar is fitted. Alternatively or additionally, at least one portion end of the casing may comprise at least one groove or at least one shoulder into which the longitudinal part of a half-collar is fitted.

[0058] At least one half-fret may be integral with the casing. In an embodiment where the machine comprises two half-frets, the two half-frets may be integral with the casing, in particular with each of the end portions of the casing.

[0059] In one embodiment, the longitudinal portion of at least one half-fret, or even both half-frets, may be made in one piece with an end portion of the casing.

[0060] The rotor may comprise at least one flange, or even two flanges. At least one flange of the rotor may be arranged so as to maintain a non-zero minimum distance <Apar rapport à la demi-frette, la distance minimale d2 étant notamment comprise entre 1 mm et 10 mm, mieux entre 2 mm et 5 mm. Le ou les flasques du rotor peuvent être chanfreinés.

[0061] The casing may have at least one axial channel and / or at least one radial channel arranged so as to recover leaks of a cooling fluid in the rotor.

[0062] The electrical conductors may comprise one or more strands, at least one strand being formed from a hollow wire configured to be traversed by a cooling fluid.

[0063] The straight portion of each leg of at least one electrical conductor may have, for at least one strand formed from a hollow wire, a plurality of orifices for the passage of the cooling fluid. The plurality of orifices may comprise at least two end orifices intended to be arranged on either side of the stator mass.

[0064] The straight portion of each leg may have, in one embodiment, two end orifices, located on either side of the stator mass.

[0065] Each passage orifice of a leg may be located on a face of a strand of the electrical conductor extending radially relative to the longitudinal axis X.

[0066] The plurality of orifices may comprise at least one secondary orifice intended to be arranged within the stator mass, in particular in the middle thereof. In one embodiment, the plurality of orifices comprises a single secondary orifice, in particular arranged in the middle of the stator mass. Alternatively, the plurality of orifices comprises several secondary orifices, in particular two or three.

[0067] The electrical conductor may also comprise, as a variant or additionally, a strand, hollow or not, having at least one groove, the groove extending parallel to the longitudinal axis X of the stator. This strand may have a single groove. As a variant, it may have several grooves, for example two grooves. The two grooves may be arranged on either side of the strand, in particular on parallel faces of the strand.

[0068] The groove(s) may be arranged on a face of the strand, hollow or not, extending radially relative to the longitudinal axis X. Alternatively or additionally, they may be arranged on a face extending circumferentially relative to the longitudinal axis X.

[0069] At least two consecutive strands may be arranged so that two of their grooves face each other. By "consecutive strands" is meant two strands stacked on top of each other. Consecutive strands may belong to the same electrical conductor or to different conductors.

[0070] In one embodiment, the stator of a rotating electrical machine comprises at least one electrical conductor, the plurality of orifices of which comprises at least one secondary orifice intended to be arranged within the stator mass, in particular in the middle thereof, being received in the notches. The stator comprises at least one radial channel, configured to be traversed by the cooling fluid, passing at least in part through the stator yoke to at least one notch, so as to allow the circulation of the cooling fluid between the radial channel and at least one secondary orifice of at least one electrical conductor

[0071] By "radial channel" is meant a channel extending radially relative to the longitudinal axis X. The presence of a radial channel allows the fluid to arrive through the stator mass, in particular through its middle depending on the placement of the secondary orifices. A secondary orifice can thus constitute an entry point for the cooling fluid into the electrical conductor. The cooling fluid can flow axially along the longitudinal axis X on either side of a secondary orifice. In this embodiment, each end orifice can constitute an outlet for the cooling fluid from the electrical conductor.

[0072] In an embodiment where the stator comprises at least one radial channel, at least one radial channel can open onto at least one axial channel, so as to allow circulation of the cooling fluid between the radial channel and the axial channel.

[0073] The cooling fluid, in particular oil, can thus pass into the stator: either axially directly into the notches, or into axial channels formed within the stator mass, or axially inside the electrical conductors, or by a combination of these solutions. Brief description of the drawings

[0074] The invention may be better understood by reading the detailed description which follows, non-limiting examples of its implementation, and by examining the attached drawing in which:

[0075] [Fig.l] [Fig.l] is a schematic and partial longitudinal sectional view of a rotating electrical machine according to the invention.

[0076] [Fig.2a] [Fig.2a] is a schematic and partial perspective view of a half- fret used in the rotating electrical machine of [Fig.l].

[0077] [Fig.2b] [Fig.2b] is another schematic and partial perspective view of the half-fret of [Fig.2a].

[0078] [Fig.3] [Fig.3] is a schematic and partial perspective view of a half- fretted fret in the rotating electric machine of [Fig.l].

[0079] [Fig.4] [Fig.4] is a schematic and partial longitudinal sectional view, of an alternative embodiment of a rotating electrical machine.

[0080] [Fig.5] [Fig.5] is a detail view of [Fig.4] showing the presence of electrical conductors in the slots and a rotor flange.

[0081] [Fig.6] [Fig.6] is a longitudinal sectional view of an alternative embodiment of rotating electrical machine.

[0082] [Fig.7] [Fig.7] is a schematic and partial longitudinal sectional view, of an alternative embodiment of a rotating electrical machine.

[0083] [Fig.8] [Fig.8] is a longitudinal sectional view of an alternative embodiment of rotating electrical machine. Detailed description

[0084] Figures 1 to 3 illustrate a rotating electrical machine 1, which comprises a rotor 2 extending along a longitudinal axis X, a stator 3 comprising a stator mass 4. The stator mass 4 has two longitudinal ends 5 axially projecting from the rotor 2 along the longitudinal axis X. Each longitudinal end 5 can axially project beyond one end of the rotor by a distance d of approximately 5 mm.

[0085] The rotating electrical machine 1 comprises a casing 6 surrounding the rotor 2 and the stator 3. The casing 6 comprises a circumferential part 7 and two end parts 8.

[0086] The rotating electrical machine 1 comprises two half-frets 9. Each half-fret 9 defines annular chambers 10 insulating for one the coil heads and for the other the free ends of electrical conductors 11 received in notches 12 of the stator mass 4. The notches 12 are closed on the side of the rotor 2 so as to completely insulate the electrical conductors 11 from the rest of the machine.

[0087] Each half-fret 9 comprises a radial part 13 and a longitudinal part 14. The radial part 13 and the longitudinal part 14 are arranged in an L shape as shown in [Fig.l], which is a longitudinal section of the rotating electrical machine 1.

[0088] The radial part 13 of each half-fret 9 is arranged in abutment against an end face 15 of the stator mass 4.

[0089] The longitudinal part 14 of each half-fret 9 can exceed the radial part 13 of the half-fret on the stator mass side by a non-zero distance dL, forming a portion of hooping 16 inserted into the stator mass 4. The distance dL is approximately 3 mm and is less than the distance d.

[0090] The radial part 13 of each half-fret 9 is in contact with the circumferential portion 7 of the casing 6.

[0091] The longitudinal part 14 of each half-fret is fitted into a groove 17 of an end portion 8 of the casing 6.

[0092] The radial part 13 of each half-fret 9 can match the shape of the notches 12 present on the end faces 15 of the stator mass 4, in which the electrical conductors 11 are received, as illustrated in FIGS. 2a, 2b and 3.

[0093] As illustrated in figures 2a and 2b, the radial part 13 comprises twelve insertion pads 18 equidistant and equally distributed angularly with respect to the longitudinal axis X. Female receiving portions 19 are arranged on the end faces 15 of the stator mass 4.

[0094] The electrical conductors may comprise three strands 20, as illustrated in [Fig. 3]. At least one strand 20 may be formed of a hollow wire configured to be traversed by a cooling liquid.

[0095] Figures 4 and 5 show another configuration of the arrangement of the half-frets 9 in which the radial part 13 is not in abutment against an end face 15 of the stator mass 4. The radial part 13 and the longitudinal part 14 are still arranged so as to form an L.

[0096] The rotor 2, as visible in [Fig.5], has at each end a flange 21, which is chamfered.

[0097] The longitudinal part 14 of each half-fret 9 has an end 22 fretted to the rotor 2 which is chamfered, on a face directly facing the flange 21 of the rotor 2.

[0098] The flanges 21 of the rotor 2 are arranged so as to maintain a minimum distance d 2 with respect to each half-fret 9, the distance d2 being approximately 2 mm.

[0099] The half-frets 9 may be made of a non-conductive material, for example PES plastic.

[0100] Each electrical conductor 11 may comprise two legs 23 connected by a coil head 24. The annular chamber 10 shown in [Fig.5] isolates the coil heads 24 from the rest of the machine 1.

[0101] In an alternative embodiment illustrated in Figures 6 and 7, each half-fret 9 of a rotating electrical machine 1 may comprise only one longitudinal part 14. The longitudinal parts 14 of the half-frets 9 of the embodiment of [Fig.6] are each fitted into a groove 17 of the casing 6.

[0102] In an alternative embodiment illustrated in [Fig.8], the half-frets 9 comprise only one longitudinal part 14 and these longitudinal parts 14 have come each in one piece with an end portion 8 of the casing 6.

[0103] The invention is not limited to the preceding examples.

[0104] The rotating electrical machine may have only half a fret.

[0105] The half-fret(s) can come into contact with the casing by fitting into it. They can also come into contact with the casing via a shoulder.

[0106] The radial and longitudinal parts can be arranged in different ways.

[0107] The stator mass of the stator may comprise axial channels extending parallel to the longitudinal axis X, configured to be traversed by a cooling fluid.

[0108] The electrical conductors may be I-shaped. Alternatively, they may be wound to form a continuous coil.

Claims

Claims

1. Rotating electrical machine (1) comprising: - a rotor (2) extending along a longitudinal axis X, - a stator (3) comprising a stator mass (4) comprising notches (12) closed on the rotor side, the notches receiving electrical conductors (11), the stator mass having at least one longitudinal end (5) axially projecting from the rotor along the longitudinal axis X, - a casing (6) surrounding the rotor and the stator, - at least one half-hoop (9), or even two half-hoops, extending from the longitudinal end of the stator mass axially projecting from the rotor, to insulate the electrical conductors of the stator from the rotor, the half-hoop, or even each half-hoop, being formed from a single piece, the half-hoop coming into direct contact with the casing, and the half-hoop being shrunk into the longitudinal end of the stator mass.

2. Rotating electrical machine (1) according to the preceding claim, at least one half-fret (9), or even both half-frets, being formed solely from a longitudinal part (14).

3. Rotating electrical machine (1) according to one of the preceding claims, at least one half-fret (9), or even both half-frets, comprising a longitudinal part (14) and a radial part (13).

4. Rotating electrical machine (1) according to the preceding claim, the longitudinal part (14) and the radial part (13) of at least one half-fret (9) being arranged in an L shape when the half-fret is observed in longitudinal section.

5. Rotating electrical machine (1) according to one of the two preceding claims, the radial part (13) of at least one half-fret (9) being arranged in abutment against an end face (15) of the stator mass (4).

6. Rotating electrical machine (1) according to the two preceding claims, the longitudinal part (14) of the half-hoop (9) extending beyond the radial part (13) of the half-hoop on the side of the stator mass (4) by a non-zero distance dL, forming a hooping portion (16) inserted into the stator mass.

7. Rotating electrical machine (1) according to one of the two claims previous, the radial part (13) of the half-fret (9) comprising at least one insertion pad (18).

8. Rotating electrical machine (1) according to the preceding claim, at least one female receiving portion (19) being arranged on the end face (15) of the stator mass (4) to receive each insertion pad (18) of the half-hoop (9).

9. Rotating electrical machine (1) according to any one of claims 2 to 8, the rotor (2) comprising at least one flange (21), the longitudinal part (14) of at least one half-fret (9), or even of the two half-frets, comprising a fretted end (22) to the stator which is chamfered, on a face directly facing a flange of the rotor.

10. Rotating electrical machine (1) according to any one of claims 2 to 9, the casing (6) comprising a circumferential portion (7) and two end portions (8), the longitudinal part (14) of at least one half-hoop (9) being in contact with an end portion of the casing and / or the radial part (13) of at least one half-hoop being in contact with the circumferential portion of the casing.

11. Rotating electrical machine (1) according to any one of the preceding claims, the casing (6) comprising at least one groove (17) or at least one shoulder into which a half-collar (9) is fitted.

12. Rotating electrical machine (1) according to any one of the preceding claims, at least one half-fret (9) being integral with the casing (6).

13. Rotating electrical machine (1) according to any one of the preceding claims, the rotor (2) comprising at least one flange (21), or even two flanges, at least one flange of the rotor being arranged so as to maintain a non-zero minimum distance d2 relative to the half-fret, the minimum distance d2 being in particular between 1 mm and 10 mm, better still between 2 mm and 5 mm.

14. Rotating electrical machine (1) according to any one of the preceding claims, the electrical conductors (11) comprising one or more strands (20), at least one strand being formed of a hollow wire configured to be traversed by a cooling fluid.

15. Rotating electrical machine (1) according to any one of the preceding claims, the stator mass (4) comprising at least one axial channel extending parallel to the longitudinal axis X, configured to be traversed by a cooling fluid.

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