WO2023062306A2

WO2023062306A2 - Stator for a rotating electric machine

Info

Publication number: WO2023062306A2
Application number: PCT/FR2022/051896
Authority: WO
Inventors: Sara BAZHAR
Original assignee: Nidec Psa Emotors
Priority date: 2021-10-12
Filing date: 2022-10-06
Publication date: 2023-04-20
Also published as: FR3128074A1; WO2023062306A3

Abstract

Disclosed is a stator (1) for a rotating electric machine, comprising a stator mass (2) formed by a stack of sheets, the sheets comprising teeth (4) forming notches (3) therebetween which are symmetrical relative to a radial axis of the notch, and electric conductors accommodated in the notches (3), at least one of the sheets of the stator mass (2) having a plurality of slots (10) formed in the teeth (4) at the end thereof facing the air gap (E), the stator mass being composed of a plurality of packs (2a, 2b) of sheets arranged consecutively along a longitudinal axis X of the stator, the slots (10) in the sheets of a first pack (2a) being angularly offset relative to the slots in the sheets of a second pack (2b).

Description

Title: Stator of rotating electric machine

The present invention claims the priority of French application 2110780 filed on October 12, 2021, the content of which (text, drawings and claims) is incorporated herein by reference.

Technical area

The present invention relates to rotating electrical machines and more particularly to the stators of such machines. The invention relates more particularly to the stator mass of the stator and the corresponding rotating electrical machine.

The invention relates more particularly to synchronous or asynchronous alternating current machines. It relates in particular to traction or propulsion machines for electric (Battery Electric Vehicle) and/or hybrid (Hybrid Electric Vehicle - Plug-in Hybrid Electric Vehicle) motor vehicles, 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 turbine applications.

Prior technique

It is known to provide notches on the surface of the stator, at the level of the air gap with the rotor.

In particular, application EP 3 288 155 discloses a stator comprising notches arranged radially opposite the lunules provided in the notches of the stator. The notches are asymmetrical.

In application CN 108512320, the teeth of the stator have notches which house round wires. In addition, in application CN 108512320, the plates are successively offset one by one by a tooth pitch, with notches in the center of certain teeth.

In application FR 2 809 547, the stator comprises grooves which can be inclined to form a particular electrical angle between the rotor and the stator.

There is a need to improve the electromagnetic and cooling performance of rotating electrical machines, and in particular to reduce torque ripples, harmonics and noise and to limit iron losses.

Summary of the invention

The invention aims to meet all or part of these needs and thus has as its object, according to one of its aspects, a stator for a rotating electrical machine, comprising a stator mass formed of a stack of sheets, in particular sheets each in one piece, the sheets comprising teeth forming between them notches which are symmetrical with respect to a radial axis of the notch, and electrical conductors housed in the notches , at least one of the laminations of the stator mass comprising a plurality of notches provided in the teeth, at their end facing the air gap, a notch of a tooth being able in particular to be situated circumferentially between two radial edges of the said tooth , the stator mass being composed of a plurality of stacks of laminations arranged consecutively along a longitudinal axis X of the stator, the notches of the laminations of a first stack being angularly offset with respect to the notches of the laminations of a second stack .

In the invention, the notches are symmetrical with respect to a radial axis of the stator, which extends in a plane perpendicular to the longitudinal axis X of the stator and passes through the longitudinal axis X of the stator.

A further subject of the invention, independently or in combination with the foregoing, is a stator for a rotating electrical machine, comprising a stator mass formed from a stack of sheets, in particular sheets each in one piece, the sheets comprising teeth forming between them notches, which may in particular be symmetrical or asymmetrical with respect to a radial axis of the notch, and electrical conductors housed in the notches, at least one of the laminations of the stator mass comprising a plurality of notches formed in the teeth, at their end facing the air gap, a notch of a tooth being located circumferentially between two radial edges of said tooth, the stator mass being composed of a plurality of stacks of laminations arranged consecutively along a longitudinal axis X of the stator, the notches of the sheets of a first package being angularly offset with respect to the notches of the sheets of a second package.

A stack of laminations comprises several laminations, in particular at least two laminations, or even at least three laminations, or even more.

The stator mass may comprise at least two lamination packets, or even at least three or four packets. It can for example comprise two, three or four packs of sheets. The first and second packs of sheets can be consecutive.

The angular offset of the notches makes it possible to obtain a reduction in the vibration levels of certain harmonics. In addition, torque ripples can also be reduced. Finally, the average torque of the machine can also be increased.

Good results are obtained even by reducing the number of packages of the stator, so that the angular offset of the notches can make it possible to reduce the number of packages as well as the angle twisting at the rotor. This represents a gain in terms of manufacturing process, performance and vibration.

At least a portion of the electrical conductors may be U-shaped or I-shaped.

At least one of the laminations of the stator mass, better still a majority of the laminations, or even all of the laminations, comprise a plurality of notches arranged in the teeth, at their end facing the air gap. A notch of a tooth can be located circumferentially between two radial edges of said tooth.

The term “notch” designates a notch or notch made in the tooth, at the level of the air gap of the machine comprising the stator.

In the invention, a notch of a tooth can preferably be located between the two radial edges of said tooth, and not radially above a notch, in particular in the case where the notches are closed. Thus, a notch is placed in the extension of the tooth. In particular, a notch is not located above possible pole shoes of said tooth, or above a bridge of material that can connect two consecutive teeth together. A notch may not be located radially above a notch, in particular not radially above a lunula provided in a notch.

In one embodiment, a notch may be located circumferentially over a central angular extent of the tooth, in particular in the most central 80% of the tooth, or even in the most central 90% and even 95% of the tooth, being for example located more than 5%, even more than 10%, better still more than 15% from a radial edge of the tooth, measured relative to the maximum width of said tooth.

The presence of these notches in the stator allows better modulation of the source harmonics of the critical temporal mechanical orders which are likely to resonate under given spatial modes.

The angular offset according to the invention makes it possible to increase the resulting torque, to reduce the torque ripples, to reduce the levels of harmonics of magnetic origin which are a source of vibration and noise.

The presence of the notches can make it possible to reduce the noise of the machine comprising the stator.

Jamming of gear harmonics to reduce interactions between rotor harmonics and those due to slot reluctance variation can reduce air gap pressure harmonics and thus reduce noise.

The invention can also make it possible to reduce the torque ripples and to limit the iron losses. The angular offset can also allow, when assembling the stator with a rotor, a variation of reluctance along the circumferential and longitudinal axes.

Each lamination of the stator mass can be in one piece. The teeth may not be added or assembled together.

Disclosure of Invention

The laminations of a stack of stator laminations can all be identical to one another. The laminations of each stack of laminations of the stator may be identical between laminations of said stack.

The plates of two different packages can be identical to each other, being angularly offset or being turned over in order to obtain the angular offset of the notches. The sheets of two different packages can be identical to each other, not being returned. The two packages with identical sheets may or may not be consecutive. They can for example be separated by a stack of sheets having different sheets.

By “identical sheets”, it is mainly meant that said sheets are identical by the position of the notch(s).

Alternatively, the sheets of two different packages may be different from each other, the notch or notches not being placed in the same way or possibly having a different shape or size, or the number of notches being different.

By “different sheets”, it is mainly meant that said sheets differ from each other by the position of the notch(s) or by the number of notches.

In one embodiment, two sheets can have a different number of notches.

In one embodiment, the notches are offset from a longitudinal axis of the tooth, which may be an axis of symmetry for the tooth, by an angle θc. The sheets can notably differ from each other by the value of the angle 0c. The angle 0c can be different between a plate from the first stack and a plate from the second stack.

A notch can extend the full length of a stack of stator laminations. The length of a stack of stator laminations is measured along the longitudinal axis X of the stator.

A notch may not extend the full length of the stator mass.

The angular offset of the notches between two stacks of laminations of the stator can be less than one pole pitch. It may in particular be included in the following range:

0.1 7i / Ns < 0s < 2n / p, where 0s designates the angular offset between two adjacent notches of two consecutive packages of the stator, otherwise called twist angle, Ns the number of teeth of the stator and p the number of pairs of poles. The cumulative angular extent of the notches of the same tooth a Nnotches can be proportional to the angular extent Odent of said tooth on the surface of the stator at the level of the air gap. In particular, it can verify the following relationship:

0% < (a Nnotches / (Ra Odent)) < 90% with a designating the width a of a notch at the level of the air gap and Nnotches the number of notches of a tooth, Ra the bore radius of the stator, and odent the angular extent of said tooth on the surface of the stator at the level of the air gap.

In all cases, the angular extent Odent of said tooth is measured from the middle of the adjacent notch to the right of the tooth to the middle of the adjacent notch to the left of the tooth. We can also talk about dental steps. We have the relation Odent=2ÎI/NS, with Ns the number of teeth of the stator.

The position of a notch of a tooth can be defined by the relation

0 < 0c < 0.95 Odent / 2, where 0c is the angle between the longitudinal axis of a tooth, which may be a central radial axis of the tooth, and the radial axis passing through the center of said notch, and Odent the angular extent of said tooth at the surface of the stator at the air gap.

A notch may be generally symmetrical with respect to a radial axis passing through the center of said notch.

The angular offset of the notches of two packages of the stator can form a pattern with a regular offset or not, always in the same direction, or with a change of direction, for example herringbone, V, W, zig-zag.

At least a part of the electrical conductors can be in cross section of substantially rectangular shape, called flat. Electrical conductors may not have round wire.

At least some of the electrical conductors may be U-shaped or I-shaped, with a majority of the electrical conductors, or even all of the electrical conductors, being U- or I-shaped hairpin.

Electrical conductors can form a fractional winding.

The plurality of notches can comprise at least 2k notches, where k is the greatest common divisor between the number of teeth Ns and the number of poles 2p of the machine comprising the stator. We denote by p the number of pairs of poles of the machine.

The plurality of notches may comprise at least k notches regularly distributed around the longitudinal axis of the stator. In an exemplary embodiment, the sheets may comprise a plurality of notches distributed with a pattern repeating every 120°. Such a configuration can in particular be chosen when the number of teeth is 63 and the number of poles is 6. For example, the sheets can comprise three notches distributed at 120°, or six notches distributed in pairs at 120°.

In another exemplary embodiment, the sheets may comprise a plurality of notches distributed with a pattern repeating every 45°, for example eight notches distributed at 45° from each other. Such a configuration can in particular be chosen when the number of teeth is 48 and the number of poles is 8.

The plurality of notches may include at least 3k notches, or even at least 4k notches, better still at least 5k notches.

The plurality of notches may include at least 2pk notches, better still at least 3pk notches, or even at least 4pk notches, or even at least 6pk notches.

The plurality of teeth may for example comprise Ns notches, for example 2 Ns notches or even 3 Ns notches.

The plurality of notches may comprise at least three notches, better still at least six notches, for example at least 10 notches, in particular on three or six different teeth, for example consecutive or as a variant regularly distributed around a longitudinal axis of the stator, by example by pairs of notches.

The plurality of notches may comprise at least one notch on at least a quarter of the teeth, better still on at least a third of the teeth, even on at least half the teeth, even better on all the teeth of the stator.

In one embodiment, all the teeth of the stator can be provided with at least one notch. The stator may be devoid of a tooth having no notch.

As a variant, the stator may comprise teeth devoid of notches, for example at least a quarter of the teeth, better still at least a third of the teeth, or even at least half of the teeth of the stator may be devoid of notches.

Preferably, the notches are distributed over all of the teeth of the stator with regularity, for example they are one by one evenly distributed, or in pairs evenly distributed, or in groups of three notches or of four notches, the groups being regularly distributed.

All notches of the same sheet can be identical. As a variant, a sheet may comprise notches of different shapes.

At least one notch, or even a majority of the notches, better all the notches, can be located circumferentially in the middle of the two radial edges of said tooth.

As a variant, at least one notch, or even a majority of the notches, better all the notches, can be located circumferentially eccentric with respect to the middle of the two radial edges of said tooth. They can all be offset in the same direction, for example all to the right or all to the left, or as a variant alternatively offset to the right and to the left, or with yet another configuration.

Two teeth can comprise notches having different positions. Each of the teeth having at least one notch can include a notch at any position.

A tooth may comprise at least one notch, in particular a single notch, or alternatively several notches, for example two notches or three notches. The notches may or may not be arranged symmetrically on the tooth. The symmetry can be observed with respect to a longitudinal axis of the tooth, which can be an axis of symmetry for the tooth.

A tooth may comprise several notches, in particular two notches or three notches, said notches being in particular arranged symmetrically on the tooth.

The number of notches of a tooth can vary from one tooth to another tooth. In one embodiment, each tooth may include at least one notch.

The notches can be located on a single tooth or on several teeth, or even on all the teeth. The distribution of the notches can have a periodicity of the notches on 2n/k or 2îi/p. The periodicity of 2n/p can be applied in particular in the case of an entire winding. Periodicity means that formed by the pattern of all the notches arranged over an angular extent equal to 2n/k or 2i/p.

In another exemplary embodiment, the sheets may comprise a plurality of notches with different patterns on the same sheet.

Ne denotes the number of notches per tooth.

The configuration of the notches can be repeated every 2îi/k.

Over an angular extent of 2n/k, the number of teeth g on which notches can be added belongs to the following set {1, 2, ... Ns/k} . In particular, we have l<g<Ns/k. The total number of notches in a machine is then Nc*g*k.

In an exemplary embodiment, the machine can be fractional winding and comprise Ns=63 and p=3. We then have k=3. We want to add one notch per tooth, with Nc=l. The number of teeth g on which we want to add notches on an angle 2n/3 is 1 <g<21.

If g=l, then the total number of notches is Nc*g*k =1*1*3=3.

If g=2, then the total number of notches is 1*2*3=6.

If g=21. The total number of notches is 1*21*3=63.

In another exemplary embodiment, the machine can be full coil with Ns=48 and p=4. We then have k=8. We want to add one notch per tooth, with Nc=1. The number of teeth g on which one wishes to add notches on an angle 2ÎI/8 is l<g<6.

If g=1, then the total number of notches is 1*1*8=8. If g=2, then the total number of notches is 1*2*8=16.

If g=6, then the total number of notches is 1*6*8=48.

In the particular case of an entire winding, the configuration of the notches can be repeated every 2îi/p. On an angular extent of 2n/p, the number of teeth g on which we can add notches belongs to the following set {1, 2, ... Ns/p} . In particular, we have l<g<Ns/p. The total number of notches in a machine is then Nc*g*p.

In an exemplary embodiment, the machine can be full coil and include Ns=48 and p=4. We consider the case where we want to make the repeatability of the notches on an angle 27i/p=27i/4 with p=4. We want to add one notch per tooth, with Nc=1. The number of teeth g on which we want to add notches on an angle 2ÎI/4 is 1 <g<l 2.

If g=l, the total number of notches is 1*1 *4=4.

If g=2, the total number of notches is 1*2*4=8.

If g=12, the total number of notches is 1*12*4=48.

Notches

The notches may be rectangular in cross section.

The notches can be defined by two large radial sides parallel to each other.

The teeth may be defined by two large radial sides which may not be parallel to each other.

At least some of the notches may be closed, in particular at least a quarter, or even at least a third, in particular at least half of the notches may be closed. By “closed notch”, is meant notches which are not open radially towards the air gap. In one embodiment, all the slots of the stator can be closed.

Closing the slots minimizes air gap harmonics. There is a synergy with the presence of notches, which reinforces this minimization effect.

In one embodiment, at least one notch, or even each notch, can be continuously closed on the side of the air gap by a bridge of material coming in one piece with the teeth defining the notch. All the notches can be closed on the air gap side by material bridges closing the notches. The material bridges may have come in one piece with the teeth defining the notch. The stator mass then has no cutout between the teeth and the bridges of material closing the slots, and the slots are then continuously closed on the side of the air gap by the bridges of material coming in one piece with the teeth defining the notch.

In addition, the notches can also be closed on the side opposite the air gap by an added yoke or in one piece with the teeth. The notches are then not open radially outward. The stator mass may have no cutout between the teeth and the yoke.

In one embodiment, each of the notches has a continuously closed contour. By “continuously closed” is meant that the notches have a continuous closed contour when viewed in cross section, taken perpendicular to the axis of rotation of the machine. You can go all the way around the notch without encountering a cutout in the stator mass.

Alternatively, at least some of the notches may be open, in particular at least a quarter, or even at least a third, in particular at least half of the notches may be open. All stator slots can be open, with or without pole shoes. We can speak of partially open or fully open notches.

As a further variant, the stator may comprise closed slots and open slots.

Notches

The notches can all be identical from one tooth to another.

As a variant, the notches may differ from one tooth to another, for example by their size and/or by their shape.

At least one notch can have a shape, in the plane of the sheet, chosen from the following list, which is not exhaustive: partially circular, semi-circular, long ob, partially elliptical, polygonal, square, rectangular, rectangular with or without rounded corners, triangular, trapezoidal, dovetail, V-shaped or W-shaped.

In the case where the notch comprises a partially circular portion, for example semi-circular, its radius of curvature may be between 0.1 and 2 mm, better still between 0.36 and 1.8 mm, or even between 0.63 and 1.26 mm, being for example of the order of 0.36 mm or 0.4 mm or 0.6 mm or 0.63 mm or 0.8 mm or 0.9 mm or 1 mm or 1.2mm or 1.26mm or 1.4mm or 1.6mm or 1.8mm.

The radius of curvature of a rounded corner may be less than half the width a of a notch, measured circumferentially in the plane of the sheet. The radius of curvature of a rounded corner may be less than or equal to at least half the width a of a notch and its depth b, measured radially in the plane of the sheet, i.e. min (b, a/ 2).

At least one notch may comprise a partially circular or even semi-circular portion, its radius of curvature R being between 0.4 e and 2 e, better still between 0.7 e and 1.4 e, being for example of the order of e, where e denotes the width of the air gap of the machine comprising the stator.

At least one notch may have a depth b, measured radially in the plane of the sheet, less than its width a, measured circumferentially in the plane of the sheet. As a variant, the depth, measured radially in the plane of the sheet, can be greater than the width of the notch, measured circumferentially in the plane of the sheet.

A ratio a between the width a of the notch and the depth b of the notch being between 0.1 and 20, or even between 0.15 and 10, between 0.20 and 4, better still between 0.25 and 3, even between 0 ,5 and 2, being for example 0.5, 1 or 2.

We have the relation a = a b. The ratio a can be less than 1 or greater than 1 or even equal to 1.

The width a of a notch, measured circumferentially in the plane of the sheet, can be between 0.1 and 3.2 mm, or even between 0.5 and 3 mm, or even between 0.7 and 2.7 mm , better still between 1.2 and 2.4 mm, being for example of the order of 0.9 or 1 mm or 1.35 mm or even 1.8 mm.

The width a of a notch, measured circumferentially in the plane of the sheet, can be between 0.01 A and 0.45 A, better still between 0.07 A and 0.42 A, or even between 0.1 A and 0.38 A, better still between 0.17 A and 0.34 A being for example of the order of 0.13 A or 0.14 A or 0.19 A, where A denotes the width of the tooth pitch of the stator.

In one embodiment, we can have A=2TIRS/NS, and in particular

A = 7.01 mm or A = 7.08 mm, where Rs is the bore radius of the stator.

The width a of one notch, measured circumferentially in the plane of the sheet, may be less than the tooth pitch, which depends on the radius of the stator and the number of slots in the stator.

We can have a < [(2n Rs)/Ns] where Rs is the radius of the stator and Ns is the number of slots in the stator.

The width a of a notch, measured circumferentially in the plane of the sheet, can be between 0.25 e and 6 e, better still between 0.5 e and 4 e, being for example of the order of 2 e, where e denotes the width of the air gap of the machine comprising the stator.

The depth b of a notch, measured circumferentially in the plane of the sheet, can be between 0.1 and 4 mm, or even between 0.2 and 2.5 mm, or even between 0.3 and 2 mm, better between 0.4 and 1.5 mm, or even between 0.63 and 1.26 mm, being for example of the order of 0.54 mm or 0.9 mm or 1.35 mm or even 2 mm .

The depth b of a notch, measured circumferentially in the plane of the sheet, can be between 0.4 e and 3 e, better still between 0.7 e and 1.4 e, being for example of the order of e , where e designates the width of the air gap of the machine comprising the stator.

A b/a ratio can be between 0.25 and 4.

In one embodiment, a notch can be rectangular in shape, with the depth b being between 0.63 and 1.26 mm, or between 0.7 e and 1.4 e. The width a can preferably be between b and 3b, namely b<a<3b.

Finally, when the corners are rounded, we can have their radius of curvature R which verifies the relation min(a/2,b)/4 < R < min(a/2,b)

In particular, we can have b = e, a = 2b=2e, e/4<R<e, with b = 0.9 mm and a = 1.8 mm for example, and for example R=1/3 e =0.3 mm or R=0.5 e.

When we have R = e, this is the case of a semicircular notch of radius e.

In another variant embodiment, the width a can be between 0.5 e and 3 e. For the depth b, we can have a < b < 3 a, and for the rounded corners we can have the radius of curvature R which satisfies min(a/2,b)/4 < R < min(a/2,b ), or even for example 0.5 e < R < e.

In particular, a = e, b = 2 a = 2 e, R < e, and for example R=0.5 e.

In another embodiment variant, one can have the depth b=a; and for rounded corners we can have the radius of curvature R which verifies min(a/2,b)/4 < R < min(a/2,b), in particular a/8 < R <a Z2, in particular R = a/2 or R = a/4.

The width a can be in the interval [0.72 mm; 2.07 mm] or in the interval [0.8 e;

2.3 e].

In particular, we can have a=1.5 e = 1.35 mm, b = 1.5 e = 1.35 mm where e = 0.9 mm and 0.75 e/4 < R < 0.75 e ; in particular R=0.75 e=0.675 mm.

The stator mass can be made by stacking magnetic laminations, the notches being made by cutting the laminations. The closing of the slots on the side of the air gap can be obtained by material bridges coming from a single piece with the rest of the laminations forming the stator mass.

The stator may be devoid of added magnetic shims for closing the slots. This eliminates the risk of accidental detachment of these wedges.

The stator may include two electrical conductors per slot. The stator may in one embodiment comprise two columns of electrical conductor strands.

The electrical conductors can form a distributed winding. The winding can be corrugated or interleaved. The winding may not be concentrated or tooth wound. Electrical conductors can form a whole or fractional winding. The winding can be full-pitch with or without shortening, or in a fractional variant. In one embodiment, the electrical conductors form a fractional winding, in particular with a shortened pitch. We speak of fractional winding when the number of notches per pole and per phase is a fractional number. The number of slots per pole and per phase is defined by the following ratio: Ns / (Nph x 2p), where Ns is the number of teeth, Nph the number of phases and 2p the number of machine poles.

When the winding is fractional, the least common multiple between the number of teeth Ns and the number of poles 2p of the machine comprising the stator is increased. This causes the frequency of the first torque ripples to move away. The creation of the modulation of harmonics linked to the presence of the notches makes it possible to reduce the torque ripples.

The number of phases can be 3, 5, 6, 7, 9, 11, 13, 15 or other.

For a fractional winding, the number of notches per pole and per phase is fractional, i.e. the ratio q defined by Z=Ns/(2 </) is written in the form of a fraction irreducible z/m, z and m being two non-null integers, m being different from 1, where Ns is the number of notches of the stator, q the number of phases of the winding and p the number of pairs of poles.

The number of notches of the stator can be between 18 and 96, better still between 30 and 84, being for example 18, 24, 27, 30, 36, 42, 45, 48, 54, 60, 63, 72, 81 , 92, 96, better being 48 or 60 or 63. The number of poles of the stator can be between 2 and 24, or even between 4 and 12, being for example 6 or 8.

The combination number of notches/number of poles of the stator can be chosen from the combinations of the following list, which is not exhaustive: 30/4, 42/4, 45/6, 48/8, 63/6, 60/8, 84/8.

At least one first electrical conductor housed in a first notch can be electrically connected to a second electric conductor housed in a second notch, at the exit from said notches.

All the electrical conductors having a free end located at the same circumferential position around the axis of rotation of the machine, whatever their radial position, can be electrically connected together.

The stator may comprise a phase connector comprising metallic elements connected to electrical conductors of the stator. The metal elements can be arranged radially externally or internally with respect to the electrical conductors to which they are connected. The metal elements connected to conductors of the stator windings can be held by an insulating support. Furthermore, the phase connector may have lugs for connection to a power supply bus. The machine can thus be connected to an inverter, electrically connected to the connection tabs of the connector.

Pins Electrical conductors at least, see a majority of electrical conductors, better all electrical conductors, can be in the shape of pins, U or I. The pin can be U-shaped ("U-pin" in English ) or straight, being I-shaped (“I-pin”).

The electrical conductors may not form a concentrated winding, called tooth-wound.

Electrical conductors may not have round wire.

The hairpin and flat electrical conductors increase the filling factor of the slot, making the machine more compact. Thanks to a high filling coefficient, heat exchanges between the electrical conductors and the stator mass are improved, which makes it possible to reduce the temperature of the electrical conductors inside the slots.

Furthermore, the manufacture of the stator can be facilitated thanks to the electrical conductors in the form of pins. Finally, the pins do not require having open notches, we can have closed notches which allow the pins to be held and we can therefore eliminate the step of inserting the stator wedges.

Electrical conductors, or even a majority of the electrical conductors, extend axially in the slots. The electrical conductors can be introduced into the corresponding slots by one or both axial ends of the machine.

An I-shaped electrical conductor has two axial ends each placed at one of the axial ends of the stator. It passes through a single notch, and can be welded at each of its axial ends to two other electrical conductors, at the axial ends of the stator. The stator may for example comprise 6, 10, 12, 14, 18, 22 or 26 I-shaped electrical conductors, the other electrical conductors all being able to be U-shaped.

The stator may be devoid of an I-shaped electrical conductor.

A U-shaped electrical conductor has two axial ends both placed at one of the axial ends of the stator. These two axial ends are defined by the two legs of the U. It passes through two different notches, and can be welded at each of its axial ends to two other electrical conductors, at the same axial side of the stator. The bottom of the U, i.e. the side of the U forming the bun or coil head, is placed on the other axial side of the stator.

At least a portion of the electrical conductors, or even a majority of the electrical conductors, may be U-shaped hairpin.

In addition, the size of the electrical conductors at the level of the coil heads is reduced. This facilitates the interweaving of electrical conductors.

The same U-shaped electrical conductor can be placed in two different, non-consecutive slots in the stator mass of the stator. In the event that an electrical conductor is U-shaped, it can be welded to two other electrical conductors on the same side of the machine.

It is possible to interconnect two electrical conductors in the form of an I previously introduced into two different, non-consecutive slots in the stator mass of the stator. In the case where an electrical conductor is I-shaped, it can be soldered to another electrical conductor and to the connector, on the two opposite sides of the machine.

In the invention, it is possible to electrically connect together all the electrical conductors having a free end located at the same circumferential position around the axis of rotation of the machine, whatever their radial position.

Each electrical conductor may comprise one or more strands (“wire” or “strand” in English). By “strand” we mean the most basic unit for electrical conduction. A strand can be of round cross section, we can then speak of a 'thread', or flat. The flat strands can be shaped into pins, for example U or I. Each strand is coated with an insulating enamel.

The electrical conductors can be made of copper or aluminum, or any other enamelled conductive material or coated with any other suitable insulating coating.

The stator mass can be produced by stacking sheets. The teeth can be interconnected by material bridges, and on the opposite side by a yoke. The notches can be closed. They can be produced entirely by cutting in the sheets. Each sheet of the stack of sheets can be monobloc.

Each sheet is for example cut from a sheet of magnetic steel or sheet containing magnetic steel, for example steel 0.1 to 1.5 mm thick. The sheets can be coated with an electrically insulating varnish on their opposite faces before they are assembled within the stack. Electrical insulation can still be obtained by heat treatment of the sheets, if necessary.

The stator may include an outer carcass surrounding the yoke.

The stator teeth can be made with a stack of magnetic laminations, each covered with an insulating varnish, in order to limit the losses by induced currents.

Machine

Another subject of the invention, according to another of its aspects, independently or in combination with the foregoing, is a rotating electrical machine comprising a stator as defined above.

The rotating electrical machine can be synchronous or asynchronous. The machine can be used as a motor or as a generator. The machine can be reluctance. She can constitute a synchronous motor or alternatively a synchronous generator. As a further variant, it constitutes an asynchronous machine.

The maximum speed of rotation of the machine can be high, being for example greater than 10,000 rpm, better still greater than 12,000 rpm, being for example of the order of 14,000 rpm to 15,000 rpm. min, or even 20,000 rpm or 24,000 rpm or 25,000 rpm. The maximum speed of rotation of the machine may be less than 100,000 rpm, or even 60,000 rpm, or even even less than 40,000 rpm, better still less than 30,000 rpm.

The invention may be particularly suitable for high-powered machines.

Rotor

The rotating electrical machine may include a rotor. The rotor may comprise a rotor mass and permanent magnets inserted therein. The rotor can be permanent magnets, with surface or buried magnets. The rotor can be flux concentrating. It may comprise one or more layers of magnets arranged in an I, U or V. The rotor may have no squirrel cage.

Alternatively, it may be a wound or squirrel cage rotor, or a variable reluctance rotor.

The rotor mass can extend along the axis of rotation and be arranged around a shaft. The shaft may include torque transmission means for driving the rotor mass in rotation.

The rotor may include permanent magnets inserted into the rotor mass. The rotor mass may comprise rotor laminations. The housings for the permanent magnets can be produced entirely by cutting in the sheets. Each sheet of the stack of sheets can be monobloc.

The number of pairs of poles at the rotor is for example between 1 and 24, being for example 1, 2, 3, 4, 5 or 6.

The diameter of the rotor may be less than 600 mm, or even less than 400 mm, better still less than 300 mm, better still less than 200 mm, and greater than 40 mm, better greater than 60 mm, being for example between 80 and 160 mm.

The shaft can be made of a magnetic material, which advantageously makes it possible to reduce the risk of saturation in the rotor mass and to improve the electromagnetic performance of the rotor.

As a variant, the rotor comprises a non-magnetic shaft on which the rotor mass is arranged. The shaft can be made at least in part from a material from the following list, which is not exhaustive: steel, stainless steel, titanium or any other non-magnetic material. The rotor mass can in one embodiment be placed directly on the non-magnetic shaft, for example without an intermediate rim. As a variant, in particular in the case where the shaft is not non-magnetic, the rotor may comprise a rim surrounding the shaft of the rotor and coming to rest on the latter.

The rotor mass may include one or more holes to lighten the rotor, allow its balancing or for the assembly of the rotor plates constituting it. Holes can allow passage of the tie rods now integral with the sheets.

Sheets can be cut in a tool one after the other. They can be stacked and clipped or glued into the tool, in complete bundles or sub-bundles. The sheets can be clicked on top of each other. Alternatively, the stack of sheets can be stacked and welded outside the tool.

The rotor mass may have an outer contour which is circular or multi-lobed, a multi-lobed shape being useful for example to reduce torque ripples or current or voltage harmonics.

The rotor can be cantilevered or cantilevered from the bearings used to guide the shaft.

The machine may comprise a single inner rotor or, as a variant, an inner rotor and an outer rotor, arranged radially on either side of the stator and coupled in rotation.

The machine can be inserted alone into a casing or inserted into a gearbox casing. In this case, it is inserted into a casing which also houses a gearbox.

Yrilled Rotor

In one embodiment, the rotor may comprise a rotor mass and permanent magnets inserted therein, the rotor mass being composed of a plurality of packages arranged consecutively along an axis of rotation of the rotor, two consecutive packages being angularly offset around the axis of rotation of the rotor by an elementary angle θr.

The rotor may in particular comprise a first stack of laminations and a second stack of laminations.

Such a rotor is said to be 'twisted'. The rotor can advantageously be twisted, particularly in the case where the stator comprises a full-pitch winding. The invention can make it possible to reduce the number of packages needed by the rotor. When the rotor is twisted, the reduction of torque ripples can be further improved.

The invention can thus make it possible to simplify the method of manufacturing the machine, to improve the precision of the method, and to reduce its cost, by making it possible to reduce the stages of assembly of the stator and/or the rotor, by reducing the number of stacks of laminations to the stator and/or to the rotor, and by reducing the assembly steps of the rotor.

Alternatively, the rotor may not be twisted. We then speak of a so-called ‘straight’ rotor. The rotor may advantageously be straight, particularly in the case where the stator comprises a fractional-pitch winding.

Rotor notches

The rotor may comprise a rotor mass formed of a stack of laminations, in particular of laminations each in one piece, at least one of the laminations of the rotor mass comprising a plurality of notches on the surface of the rotor mass facing in the air gap.

The notches of the rotor can all be identical or different. They may differ, for example, in their size and/or in their shape. The notches of the rotor can be provided facing the air gap, on the surface of the rotor or slightly buried.

The notches of the rotor can be identical to or different from the notches of the stator.

At least one notch of the rotor may have a shape, in the plane of the sheet, chosen from the following list, which is not exhaustive: partially circular, semi-circular, oblong, partially elliptical, polygonal, square, rectangular, rectangular with or without rounded corners, triangular, trapezoidal, dovetail, V-shaped or W-shaped.

In the case where the notch comprises a partially circular portion, for example semi-circular, its radius of curvature can be between 0.1 and 4 mm, better still between 0.36 and 3 mm, or even between 0.63 and 2 mm. , being for example of the order of 0.36 mm or 0.4 mm or 0.6 mm or 0.63 mm or 0.8 mm or 0.9 mm or 1 mm or 1 .2 mm or 1.26 mm or 1.4 mm or 1.6 mm or 1.8 mm.

The radius of curvature of a rounded corner may be less than half the width a of a notch, measured circumferentially in the plane of the sheet. The radius of curvature of a rounded corner may be less than or equal to at least half the width ar of a notch and its depth br, measured radially in the plane of the sheet, i.e. min (br, ar/ 2).

At least one notch of the rotor may include a partially circular or even semi-circular portion, its radius of curvature R being between 0.4 e and 8 e, better still between 0.7 e and 4 e, being for example order of e, where e denotes the width of the air gap of the machine comprising the stator. At least one notch of the rotor can have a depth br, measured radially in the plane of the sheet, less than its width ar, measured circumferentially in the plane of the sheet.

As a variant, the depth, measured radially in the plane of the sheet, can be greater than the width of the notch of the rotor, measured circumferentially in the plane of the sheet.

The width ar of the notches of the rotor can be included in the interval [0; 5 a] where a is the width of the notches at the stator. The depth br of the notches at the rotor can be included in the interval [0;5 b], where b is the depth of the notches at the stator.

The notches of the laminations of a first pack of the rotor mass can be angularly offset with respect to the notches of the laminations of a second pack of the rotor mass.

The laminations of a stack of rotor laminations can all be identical to each other.

The laminations of each stack of laminations of the rotor may be identical between laminations of said stack.

In one embodiment, two sheets can have a different number of notches.

In one embodiment, the detents are offset relative to a longitudinal axis of the rotor pole, which may be an axis of symmetry for the pole, by an offset angle. The sheets may in particular differ from each other by the value of the offset angle. The offset angle can be different between a sheet of the first package and a sheet of the second package. The angular offset of the notches of two packages of the rotor can form a pattern with a regular offset or not, always in the same direction, or with a change of direction, for example herringbone, V, W, zig-zag.

Alternatively, the rotor may be devoid of notches on the surface of the rotor mass. The surface of the rotor mass can be substantially smooth.

Rotor packages

The rotor mass may comprise an even number of packets. As a variant, the rotor mass can comprise an odd number of packets.

The angular offset between two consecutive bunches can be constant when moving along the axis of rotation of the rotor, or alternatively it can vary.

The packages of the rotor mass can all be angularly offset in the same direction around the axis of rotation of the rotor.

As a variant, they can be angularly offset successively in one direction then in the other, being arranged in a V. They can be arranged in a V, being offset symmetrically with respect to a plane of symmetry perpendicular to the axis of rotation of the rotor. An advantage of the V configuration is to allow the axial force to be minimized. If the number of bunches twisted in one direction is n, the total number nt of bunches in V will be nt = 2n or nt = 2n -1.

The rotor mass may comprise a single central packet cut in two by said plane of symmetry.

As a variant, the rotor mass can comprise two central packets separated by said plane of symmetry. The two central packages may not be angularly offset from each other.

The total number of bunches can be equal to the number n of consecutive bunches shifted in the same direction around the axis of rotation, or alternatively equal to 2n, or else to 2n-1.

As a further variant, the packets of the rotor mass can be angularly offset successively in one direction and then in the other, being arranged in herringbone pattern.

In one embodiment, it is possible to further reduce the pressure harmonics and the noise levels by twisting n packets, in particular herringbone or V-shaped, and by multiplying this pattern r times over the length of the rotor.

All rotor packages can each have the same length or different lengths

Alternatively, two packets may have different lengths. For example, the arrangement of the bundles in the rotor mass can be such that the length of the bundles can increase and then decrease as one moves along the axis of rotation, or increase all along the rotor, or decrease all the way. along the rotor. As a further variant, the length of the packets may vary with a sawtooth variation as one moves along the axis of rotation.

In one embodiment, the central packet or packets may have a different length from the other packets, for example a shorter or longer length.

Brief description of the drawings

The invention may be better understood on reading the detailed description which follows, of a non-limiting example of embodiment thereof, and on examining the appended drawing, in which:

[Fig 1] Figure 1 is a view, schematic and partial, of a rotating electrical machine stator sheet,

[Fig la] figure la is a detail view of figure 1,

[Fig 1b] figure 1b is a detail view of figure 1,

[Fig 2] Figure 2 is a view similar to Figure 1 of an alternative embodiment,

[Fig 2a] Figure 2a is a view similar to Figure 1 of a variant embodiment, [Fig 2b] Figure 2b is a view similar to Figure 1 of a variant embodiment, [Fig 2c] Figure 2c is a view similar to FIG. 1 of a variant embodiment, [Fig 2d] FIG. 2d is a view similar to FIG. 1 of a variant embodiment, [Fig 2e] FIG. 2e is a view similar to Figure 1 of a variant embodiment, [Fig 2f] Figure 2f is a view similar to Figure 1 of a variant embodiment, [Fig 2g] Figure 2g is a view similar to Figure 1 of a embodiment variant,

[Fig 2h] figure 2h is a view similar to figure 1 of an alternative embodiment,

[Fig 3] Figure 3 is a view similar to Figure 1 of a variant embodiment, [Fig 3a] Figure 3a is a view similar to Figure 1 of a variant embodiment,

[Fig 3b] Figure 3b is a view similar to Figure 1 of an alternative embodiment,

[Fig 3c] figure 3c is a view similar to figure 1 of a variant embodiment, [fig 3d] figure 3d is a view similar to figure 1 of a variant embodiment, [fig 3e] figure 3e is a view similar to FIG. 1 of a variant embodiment, [Fig 3f] FIG. 3f is a view similar to FIG. 1 of a variant embodiment, [Fig 4] FIG. 4 is a view similar to Figure 1 of a variant embodiment, [Fig 5] Figure 5 is a view similar to Figure 1 of a variant embodiment, [Fig 6] Figure 6 is a view similar to Figure 1 of variants of embodiment, [Fig 7] Figure 7 is a view similar to Figure 1 of an alternative embodiment,

[Fig 8] Figure 8 is a perspective view, schematic and partial, of an alternative embodiment, [Fig 8a] Figure 8a is a sectional view, schematic and partial, of the machine of Figure 8,

[Fig 8b] Figure 8b is another sectional view, schematic and partial, of the machine of Figure 8,

[Fig 9] figure 9 is a perspective view, schematic and partial, of an alternative embodiment,

[Fig 9a] Figure 9a is a schematic partial sectional view of the machine of Figure 9,

[Fig 9b] figure 9b is another sectional view, schematic and partial, of the machine of figure 9,

[Fig 9c] figure 9c is another sectional view, schematic and partial, of the machine of figure 9,

[Fig 9d] figure 9d is another sectional view, schematic and partial, of the machine of figure 9,

[Fig 10] Figure 10 is a perspective view, schematic and partial, of an alternative embodiment,

[Fig 10a] figure 10a is a schematic and partial sectional view of the machine of figure 10,

[Fig 10b] figure 10b is another sectional view, schematic and partial, of the machine of figure 10,

[Fig 10c] figure 10c is another sectional view, schematic and partial, of the machine of figure 10,

[Fig lOd] figure lOd is another sectional view, schematic and partial, of the machine of figure 10,

[Fig 11] Figure 11 is a perspective view, schematic and partial, of an alternative embodiment,

[Fig l ia] Figure 1 la is a sectional view, schematic and partial, of the machine of Figure 11,

[Fig 11b] figure 11b is another sectional view, schematic and partial, of the machine of figure 11,

[Fig 12] figure 12 is a perspective view, schematic and partial, of an alternative embodiment,

[Fig 12a] Figure 12a is a schematic and partial sectional view of the machine of Figure 12, [Fig 12b] figure 12b is another sectional view, schematic and partial, of the machine of figure 12,

[Fig 12c] figure 12c is another sectional view, schematic and partial, of the machine of figure 12,

[Fig 12d] figure 12d is another sectional view, schematic and partial, of the machine of figure 12,

[Fig 13] Figure 13 is a sectional view, schematic and partial, of a rotor embodiment variant,

[Fig 14] Figure 14 is a sectional view, schematic and partial, of an alternative machine embodiment,

[Fig 15] figure 15 is a sectional view, schematic and partial, of a rotor embodiment variant,

[Fig 16] figure 16 is a sectional view, schematic and partial, of a rotor embodiment variant,

[Fig 17] figure 17 is a sectional view, schematic and partial, of an alternative rotor embodiment,

[Fig 18] Figure 18 is a sectional view, schematic and partial, of an alternative stator embodiment.

detailed description

There is illustrated in Figures 1, la and 1b a stator 1 of a rotating electrical machine, comprising a stator mass 2 comprising notches 3 and teeth 4 defining between them the notches, the teeth being attached to a yoke 57. The notches of the stator are here closed by bridges of material 60.

The stator can be associated with a rotor, not shown in FIG. 1, being separated from the latter by an air gap E of zero width.

The stator 1 may comprise a winding not visible in the figure, comprising electrical conductors housed in the notches 3. The electrical conductors are in cross section of generally rectangular shape, with rounded corners. They can be superimposed radially in a single row. The circumferential dimension of an electrical conductor corresponds substantially to the width of a notch.

The electrical conductors are made of copper or aluminium, or any other enamelled conductive material or coated with any other suitable insulating coating. The electrical conductors can be in the shape of a U-shaped or I-shaped hairpin. They can each comprise first and second legs intended to extend axially respectively in first and second notches of the stator.

The stator mass 2 is formed from a stack of magnetic laminations each in one piece. Each lamination of the stator mass can be in one piece. Each sheet has teeth 4 forming between them notches 3.

The notches 3 are rectangular in cross section, and they are defined by two large radial sides 12 parallel to each other.

The teeth are defined by two large radial sides 12 which are not mutually parallel.

Notches

The sheet has a plurality of notches 10 formed in the teeth 4, at their end facing the air gap E. A notch 10 of a tooth 4 is located circumferentially between the two radial edges 12 of said tooth. Thus, notch 10 of a tooth is not located radially above a notch. Notch 10 is not spared in a bridge of material 60 connecting two consecutive teeth together.

In the example described, each tooth 4 comprises a single notch 10, all the teeth 4 comprise a notch 10, and the notches are thus regularly distributed around the longitudinal axis of the stator. The stator thus has as many notches 10 as teeth 4, i.e. 63.

In addition, the notches 10 are here arranged centrally, that is to say they are located circumferentially in the middle of the two radial edges 12 of said tooth 4. The longitudinal axis of the tooth 4 is thus an axis of symmetry for the tooth.

In the example described, the notches have a substantially rectangular shape with rounded corners. The width a can be defined by one notch, measured circumferentially in the plane of the sheet, as well as the depth b, measured radially in the plane of the sheet. The depth b is here less than the width a.

R is the radius of curvature of the rounded corners.

In the example described, we have R = 0.4 mm, a = 1 mm and b = 0.54 mm.

Alternatively, the notch may have a different shape.

By way of example, there is illustrated in FIG. 2 a sheet comprising a notch of semi-circular shape, of radius R. The radius of curvature R can be between 0.1 and 2 mm, better still between 0.36 and 1.8 mm, or even between 0.63 and 1.26 mm.

FIGS. 2a to 2h show different possibilities of curvature. The radius of curvature R can be for example of the order of 0.36 mm, as illustrated in FIG. 2a, or 0.4 mm as illustrated in FIG. 2b, or 0.6 mm as illustrated in FIG. 2c, or 0.63 mm as shown in Figure 2d, or 0.9mm as shown in Figure 2e, or 1.26mm as shown in Figure 2f, or 1.6mm as shown in Figure 2g, or 1.8 mm as shown in Figure 2h.

In another embodiment variant, the shape of the notch is strictly rectangular, as illustrated in figure 3.

It is possible to define a ratio a between the width a of the notch and the depth b of the notch being between 0.20 and 4, better still between 0.25 and 3, being for example 0.5, 1 or 2. We have the relation a = a b. The ratio a can be greater than 1, as shown in Figure 3a with a = 2, or equal to 1 as shown in Figure 3b, or even smaller than 1 as shown in Figure 3c with a = 0.5 .

In the embodiment illustrated in FIG. 3d, the notch is rectangular in shape with rounded corners, with the depth b=0.9 mm and a=1.8 mm, and R=0.3 mm.

In another alternative embodiment illustrated in FIG. 3e, the notch is rectangular in shape with a semi-circular bottom. We have in particular a = e, b = 2 a = 2 e, and R = 0.5 e.

In another alternative embodiment illustrated in FIG. 3f, the notch is rectangular in shape with a semi-circular bottom. We have in particular a = 1.5 e = 1.35 mm, b = 1.5 e = 1.35 mm, where e = 0.9 mm and R = 0.75 e = 0.675 mm.

The notches could of course be of yet another shape. By way of example, notches 10 in the shape of a trapezium have been illustrated in FIG. 4, and in FIG. 5 notches 10 in the shape of a dovetail.

Oblong, rectangular and triangular notches have also been illustrated in FIG. 6. We have here in the three examples a=0.6 mm and b=0.3 mm. The dimensions of the notches are the same for the three embodiments.

The notches could still be partially circular, polygonal, square, V-shaped or W-shaped.

Angular offset at the stator

Furthermore, in the invention, the notches 3 are symmetrical with respect to a radial axis of the stator, which extends in a plane perpendicular to the longitudinal axis X of the stator and passes through the longitudinal axis X of the stator.

In addition, in the examples which have just been described, the notches are arranged in the middle of the teeth, on the longitudinal axis Z thereof.

As a variant, as illustrated in FIG. 7, the notches 10 can be offset with respect to a longitudinal axis Z of the tooth, which here is an axis of symmetry Z for the tooth, by an angle θc.

It can also be seen that the cumulative angular extent of the notches of the same tooth a Nnotches is proportional to the angular extent Odent of said tooth on the surface of the stator at the level of the air gap, verifying the following relationship:

Furthermore, the position of notch 10 of tooth 3 can be defined by the relation 0 < 0c < 0.95 Odent / 2, where 0c is the angle between the longitudinal axis of the tooth, which is a central radial axis Z of the tooth, and the radial axis Y passing through the center of said notch, and Odent the angular extent of said tooth at the surface of the stator at the level of the air gap.

The notch 10 is here symmetrical with respect to the radial axis Y passing through the center of said notch.

The stator 1 according to the invention is also characterized by the fact that the stator mass 2 is composed of a plurality of stacks of laminations 2a, 2b arranged consecutively along the longitudinal axis X of the stator. According to the invention, the notches 10 of the sheets of a first package 2a are angularly offset with respect to the notches 10 of the sheets of a second package 2b by an angle 0s, as illustrated in figure 8.

Thus, the laminations of different packages of the stator may in particular differ from each other by the value of the angle θc. The angle θc can be different between a plate from the first stack and a plate from the second stack, as described below.

In the example of FIG. 8, the notches 10 of the first stack of plates 2a are offset by an angle Ocl of −1.5° relative to the longitudinal axis Z of the tooth, which is a central radial axis Z of the tooth, as illustrated in FIG. 8a, while the notches 10 of the second stack of sheets 2b are offset by an angle θc2 of 1.5° relative to the longitudinal axis Z of the tooth, as illustrated in Figure 8b. Position 0 _ci designates the position of the notch at stack i of the stator.

Thus, each tooth of the stator has a notch, and the stator allows twisting of the notches at a total angle of 3°. The same sheet is here turned over to create a twist of notches along the Z axis. The sheets of a stack of stator sheets are all identical to each other, and the notches extend over the entire length of a stack of the stator.

The rotor 50 with which the stator 1 is associated comprising a rotor mass 55 and permanent magnets 56 inserted therein. The rotor mass is made up of a plurality of packets 50a, 50b arranged consecutively along an axis of rotation of the rotor. Two consecutive packets are angularly offset around the axis of rotation of the rotor by an elementary angle θr. In the example of FIGS. 8 to 8b, the rotor 50 comprises a single version of laminations, which are arranged in two packets 50a, 50b offset by an angle of +/-3.75°. As illustrated, the first packet 50a is offset by an angle θr1 of -3.75°, and the second packet 50b is offset by an angle θr2 of 3.75°. Position 0 _ri designates the position of stack i of the rotor. The total angle of offset to the rotor is 7.5°.

The stator mass may comprise two packs of laminations, as described with reference to FIG. 8. As a variant, it may for example comprise four packs of laminations 2a, 2b, 2c, 2d, as illustrated in the example of FIG. 9. In this example, the sheets of two different packages can be different from each other, the notch or notches not being placed in the same way. Thus, each tooth of the stator has a notch 10, and the stator has two versions of sheets, which can be turned over.

In the example of Figures 9 to 9d, the notches 10 of the first stack of plates 2a are offset by an angle θcl of -2.25° relative to the longitudinal axis Z of the tooth, which is a central radial axis Z of the tooth, as illustrated in FIG. 9a, the notches 10 of the second stack of sheets 2b are offset by an angle θc2 of −0.75° with respect to the longitudinal axis Z of the tooth, as illustrated in FIG. 9b, the notches 10 of the third stack of plates 2c are offset by an angle θc3 of 0.75° relative to the longitudinal axis Z of the tooth, as illustrated in FIG. 9c, and the notches 10 of the fourth stack of sheets 2d are offset by an angle θc4 of 2.25° with respect to the longitudinal axis Z of the tooth.

The total offset angle at the stator is 4.5°, and the fourth sheet corresponds to the first sheet turned over, and the third sheet to the second sheet turned over.

As regards the rotor 50, it also comprises four packets 50a, 50b, 50c, 50d, with a total angular offset of 5.62°. In this example of FIGS. 9 to 9d, the rotor 50 comprises a single version of plates, which are arranged in four packets 50a, 50b, 50c, 50d, offset by an angle of +/-2.81° or of +/ -0.94°.

As illustrated, the first packet 50a is offset by an angle θr1 of - 2.81°, the second packet 50b is offset by an angle θr2 of - 0.94°, the third packet 50c is offset by an angle θr3 of 0.94°, and the fourth packet 50d is offset by an angle θr4 of 2.81°.

As a further variant, the stator mass may for example comprise four packets of laminations 2a, 2b, 2c, 2d, as illustrated in the example of FIG. 10, with the two identical central packets 2b and 2c, which therefore do not form only one. Thus, in this example, the sheets of two different packages can be identical to each other, not being returned.

In addition, this example differs from the previous ones in that on the stator only one tooth out of three has a notch 10.

In the example of Figures 10 to 10d, the notches 10 of the first stack of sheets 2a are offset by an angle θcl of 0.75° relative to the longitudinal axis Z of the tooth, which is a radial axis center Z of the tooth, as shown in Figure 1 Oa, the notches 10 of the second stack of sheets 2b are offset by an angle θc2 of 0°, as shown in Figure 10b, the notches 10 of the third stack of sheets 2c are offset by an angle θc3 of 0°, as illustrated in FIG. 10c, and the notches 10 of the fourth stack of sheets 2d are offset by an angle θc4 of −0.75°.

The total offset angle at the stator is 1.5°, and the fourth sheet corresponds to the first sheet turned over, and the third sheet and the second sheet are identical.

As regards the rotor 50, it also comprises four packets 50a, 50b, 50c, 50d, with a total angular offset of 7.5°. In this example of FIGS. 10 to 10d, the rotor 50 comprises a single version of sheets, which are arranged in four packets 50a, 50b, 50c, 50d, offset by an angle of +/-3.75° or +/ -1.25°.

As illustrated, the first packet 50a is offset by an angle θr1 of -3.75°, the second packet 50b is offset by an angle θr2 of -1.25°, the third packet 50c is offset by an angle θr3 of 1.25°, and the fourth packet 50d is offset by an angle θr4 of 3.75°.

In the alternative embodiment illustrated in FIGS. 11, 1 la and 11b, the rotor has a single version of sheet metal and is not twisted. In other words 0rl = 0°.

The stator mass 2 of the stator 1 is made up of two packs of laminations 2a, 2b arranged consecutively along the longitudinal axis X of the stator. The notches 10 of the sheets of the first package 2a are angularly offset by an angle θcl of -0.25°, as illustrated in FIG. 1 ia, while the notches 10 of the second package of sheets 2b are offset by an angle θc2 0.25°, as shown in Figure 11b.

Each tooth of the stator has a notch, and the stator allows twisting of the notches at a total angle of 0.5°. The same sheet is here turned over to create a twist of notches along the Z axis. The sheets of a stack of stator sheets are all identical to each other, and the notches extend over the entire length of a stack of the stator.

In the alternative embodiment illustrated in FIGS. 12 and 12a to 12d, the stator mass 2 of the stator 1 is made up of two stacks of laminations 2a, 2b arranged consecutively along the longitudinal axis X of the stator. The notches 10 of the sheets of the first stack 2a are angularly offset by an angle θcl=θc2 of -0.75°, as illustrated in FIGS. 12a and 12b, while the notches 10 of the second stack of sheets 2b are offset by one angle θc3 = θc4 of 0.75°, as shown in Figures 12c and 12d.

Each tooth of the stator has a notch, and the stator allows twisting of the notches at a total angle of 1.5°. The same sheet is here turned over to create a twist of notches along the Z axis. The sheets of a stack of stator sheets are all identical to each other, and the notches extend over the entire length of a stack of the stator. As regards the rotor 50, it comprises four packets 50a, 50b, 50c, 50d, with a total angular offset of 7.5°. In this example of FIGS. 12 to 12d, the rotor 50 comprises a single version of plates, which are arranged in four packets 50a, 50b, 50c, 50d, offset by an angle of +1-3.15° or +/ -1.25°.

Rotor notches

In an alternative embodiment illustrated in Figure 13, the laminations of the rotor mass have notches 62 on the surface of the rotor mass facing the air gap E.

In this example, the notches are of partially elliptical shape, with a depth br, measured radially in the plane of the sheet, greater than the width ar of the notch 62, measured circumferentially in the plane of the sheet. The width ar of the notches of the rotor can be included in the interval [0; 5 a] where a is the width of the notches at the stator. The depth br of the notches at the rotor can be included in the interval [0; 5 b], where b is the depth of the notches in the stator.

In the example of Figure 13, a pole of the rotor has four notches 62 distributed symmetrically on either side of an axis of the pole.

In the variant of Figure 14, a pole of the rotor has three notches 62 also symmetrically distributed, with a central notch on the axis of the pole.

In particular when the notches of a pole are not distributed symmetrically, the notches of the laminations of a first package of the rotor mass are angularly offset with respect to the notches of the laminations of a second package of the rotor mass.

By way of example, there is illustrated in FIG. 15 a rotor formed of two identical sheets turned over, in order to form two packets 50a, 50b of sheets each comprising two notches 62 angularly offset.

In the example of Figure 16, the packets 50a, 50b of sheets each have a single notch 62 angularly offset.

In the example of Figure 17, the rotor comprises four packets 50a, 50b, 50c, 50d, each comprising a single notch 62 angularly offset. The notches 62 here differ in their depth.

Finally, in the example of figure 18, the stator is formed of two packages 2a, 2b comprising identical sheets not turned over but angularly offset, in order to allow the angular offset of the notches 10. Of course, it is not beyond the scope of the present invention if the stator and/or the rotor comprises a configuration different from those illustrated, for example by the number of packets, by the position of the notches or their shape or size.

Claims

1. Stator (1) of a rotating electric machine, comprising a stator mass (2) formed of a stack of sheets, in particular sheets each in one piece, the sheets comprising teeth (4) forming between them notches ( 3) which are symmetrical with respect to a radial axis of the notch, and electrical conductors housed in the notches (3), at least one of the laminations of the stator mass (2) comprising a plurality of notches (10) formed in the teeth (4), at their end facing the air gap (E), a notch (10) of a tooth being in particular situated circumferentially between two radial edges (12) of the said tooth (4), the mass stator being composed of a plurality of stacks (2a, 2b) of laminations arranged consecutively along a longitudinal axis X of the stator, the notches (10) of the laminations of a first stack (2a) being angularly offset with respect to the notches of the sheets of a second package (2b), at least a part of the electrical conductors being in cross section of substantially rectangular shape, called flat.

2. Stator according to the preceding claim, the laminations of a pack of laminations of the stator all being identical to each other.

3. Stator according to one of the two preceding claims, a notch (10) extending over the entire length of a stack of stator laminations.

4. Stator according to any one of the preceding claims, the angular offset (0s) of the notches between two stacks of laminations of the stator being less than one pole pitch.

5. Stator according to any one of the preceding claims, the cumulative angular extent of the notches of the same tooth (a Nnotches) being proportional to the angular extent (Odent) of said tooth on the surface of the stator at the level of the air gap, verifying in particular the following relation: 0% < (a Ncrans / (Ra Odent)) < 90% with a which designates the width a of a notch at the level of the air gap and Ncrans the number of notches of a tooth, Ra the bore radius of the stator, and Odent the angular extent of said tooth on the surface of the stator at the air gap.

6. Stator according to any one of the preceding claims, in which the position of a notch of a tooth is defined by the relation

7. Stator according to any one of the preceding claims, at least a part of the electrical conductors being in cross section of substantially rectangular shape, called flat.

8. Stator according to any one of the preceding claims, at least some of the electrical conductors being hairpin-shaped in U or I, or even a majority of the electrical conductors, or even all the electrical conductors, being hairpin-shaped. in U or in I.

9. Rotary electrical machine comprising a stator (1) according to any one of the preceding claims and a rotor (50).

10. Machine according to the preceding claim, the rotor (50) comprising a rotor mass (55) and permanent magnets (56) inserted therein, the rotor mass (55) being composed of a plurality of packages (50a, 50b) arranged consecutively along an axis of rotation of the rotor, two consecutive packets being angularly offset around the axis of rotation of the rotor by an elementary angle (Or).

11. Machine according to one of the two preceding claims, the rotor (50) comprising a rotor mass (55) formed of a stack of sheets, in particular of sheets each in one piece, at least one of the sheets of the rotor mass (55) having a plurality of notches (62) on the surface of the rotor mass facing the air gap (E).

12. Machine according to the two preceding claims, the notches (62) of the sheets of a first package (50a) of the rotor mass being angularly offset with respect to the notches (62) of the sheets of a second package of the rotor mass ( 50b).

13. Rotating electric machine comprising:

- a stator (1) comprising a stator mass (2) formed of a stack of laminations, in particular laminations each in one piece, the laminations comprising teeth (4) forming between them notches (3) which are symmetrical relative to a radial axis of the notch, and electrical conductors housed in the notches (3), at least one of the laminations of the stator mass (2) comprising a plurality of notches (10) made in the teeth ( 4), at their end facing the air gap (E), a notch (10) of a tooth being in particular located circumferentially between two radial edges (12) of said tooth (4), the stator mass being composed of a plurality of packs (2a, 2b) of laminations arranged consecutively along a longitudinal axis X of the stator, the notches (10) of the laminations of a first pack (2a) being angularly offset with respect to the notches of the laminations of a second packet (2b), and

- A rotor (50) right untwisted.

14. Stator (1) of a rotating electrical machine, comprising a stator mass (2) formed of a stack of sheets, in particular sheets each in one piece, the sheets comprising teeth (4) forming between them notches (3), which are in particular symmetrical or asymmetrical with respect to a radial axis of the notch, and electrical conductors housed in the notches (3), at least one of the plates of the stator mass (2) comprising a plurality of notches (10) formed in the teeth (4), at their end facing the air gap (E), a notch (10) of a tooth being located circumferentially between two radial edges (12) of said tooth (4), the stator mass being composed of a plurality of packets (2a, 2b) of laminations arranged consecutively along a longitudinal axis X of the stator, the notches (10) of the laminations of a first package (2a) being angularly offset with respect to the notches of the sheets of a second package (2b), at least a part of the electrical conductors being in cross section of substantially rectangular shape, called flat.