WO2023062307A1

WO2023062307A1 - End shield for a rotary electric machine

Info

Publication number: WO2023062307A1
Application number: PCT/FR2022/051899
Authority: WO
Inventors: Hussain Nouri
Original assignee: Nidec Psa Emotors
Priority date: 2021-10-12
Filing date: 2022-10-07
Publication date: 2023-04-20
Also published as: FR3128078A1

Abstract

The invention relates to an end shield (10) for a rotor of an electric machine rotating about an axis of rotation X, comprising an inner face (11) facing a rotor mass (4), an outer face (12) opposite the inner face, a radially outer edge (17) extending between the inner face and the outer face, and a central bore (13), the end shield comprising: - one or more through-openings (14) between the inner face and the outer face; and - at least one fin (15) extending at least partially into the opening.

Description

Title: Flange for rotating electrical machine

The present invention claims the priority of French application 2110789 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 those cooled by a circulation of a cooling fluid, in particular air, circulating at least partially by the rotor of the 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 cool the coil heads of the stator during operation of a rotating electrical machine by a fluid, in particular by a gas, in particular by air circulating in the electrical machine.

Such electric machines often have localized high temperature zones close to the winding heads of the stator and in the rotor of the electric machine. The coil heads being in contact with the cooling fluid, the quality of their cooling depends on the internal forced convection in the electrical machine.

Applications WO 2021/115806, EP 2 918 000, FR 2 988 236, FR 2 984 625, FR 2 984 630, FR 2 988 238, FR 2 988 237, FR 2 984 626, FR 2 995 171, EP 2 109 207, US 2011/0181138, EP 2605380, US 2020/0321830, FR 2887698, CN 207459903, US 2018/0337569, KR 1020180094446 and CN 210517922 disclose flanges for rotating electrical machines. The flanges have apertures and fins that extend away from the apertures.

Application EP 2 873 137 describes a fan comprising blades extending in openings. The blades are attached to the fan disc.

There is a need to further improve the cooling of rotating electrical machines cooled by a circulation of cooling fluid, in particular air.

Disclosure of Invention

The invention aims to meet this need and it achieves, according to one of its aspects, thanks to an electrical machine rotor flange rotating around an axis of rotation X, the flange comprising an inner face turned towards a mass rotor, an outer face opposite the inner face, a radially outer edge extending between the inner face and the outer face and a central bore, the flange comprising:

- one or more through openings between the inner face and the outer face, and

- at least one fin extending at least partially into the opening.

The flange according to the invention, and in particular the fins of the flange, promotes the circulation and mixing of the air at the level of the winding heads of the stator and/or inside the rotor. This improvement in air circulation improves the cooling of the electrical machine during its operation. In particular, the temperature at the stator coil heads, rotor magnets and/or phase connector can be reduced more effectively.

Furthermore, the flange according to the invention makes it possible to improve the cooling of electrical conductors of the electrical machine, which are in particular made of copper, and thus to reduce the losses by Joules effect.

In addition, the flange according to the invention makes it possible to reduce the temperature of the electrical machine and in particular the temperature of the ends of the stator coils.

A single fin can extend through an opening. As a variant, several fins, for example two, can extend through the same opening.

The flange may also include fins which do not extend through an opening. The flange may also include openings in which no fin extends at least partially.

The flange can have as many fins as there are poles of the machine. For example, the flange may comprise six fins.

The flange can have as many openings as there are poles of the machine. As a variant, the flange may comprise fewer openings than poles of the machine, the number of openings possibly being in particular equal to half the number of poles. For example, the flange may have 3 or 6 openings.

In a particular embodiment, the flange may comprise 6 openings and 6 fins, each extending at least partially into an opening. In another embodiment, the flange may have 3 openings and 6 fins, three of the fins extending at least partially into an opening and the other three fins not extending into any opening.

The opening or openings can be arranged radially between the edge and the central bore of the flange.

The flange can be manufactured by machining or by molding, in particular by foundry.

Fins

The fins can all extend over the outer face. The inner face, which is in contact with the rotor mass, can be substantially smooth. The inner face can thus be firmly attached to the rotor mass.

The fin(s) can be formed as a single piece with the flange. They may not be reported on the flange.

The manufacture of the flange is thus facilitated. In particular, it can be molded in one piece by foundry.

At least one fin may be substantially planar in shape, and may extend along a master plane.

The use of substantially planar fins facilitates their manufacture. In addition, the flat fins make it possible to have the same flow of cooling fluid, in particular of air, whatever the direction of rotation of the machine. A single type of fin can therefore be used for the entire flange. The manufacture of the flange is thus more economical. As a variant, at least one fin may comprise a curved portion, in particular in the axial direction. The latter can be curved around an axis of curvature oriented perpendicular to a radial plane containing the axis of rotation X of the electric machine. Such a curvature of the fin makes it possible to modify the direction of the flow of the cooling fluid by a certain angle in order to direct the flow towards the axial channels of the rotor mass.

At least one fin may include a straight portion and a curved portion. As a variant, at least one fin comprises two non-aligned rectilinear portions. The two rectilinear portions forming between them an angle 0 which can be between 90° and 180°, better still between 100° and 170°, better still between 110° and 160°, better still between 120° and 150°, for example of the order of 135°.

The master plane of the vane can include the axis of rotation X of the machine.

The fins can be of substantially parallelepiped shape. As a variant, at least one fin can be L-shaped. In this case, it can comprise two parallelepipedal parts arranged perpendicularly. The two parts can extend in a plane including the axis of rotation X of the machine. Each fin may comprise a part which extends over the external face of the flange and a part which extends into the opening.

A fin may comprise two substantially parallel faces oriented radially.

The term “thickness of the fin” designates the dimension of the fin measured in the circumferential direction. The term "height of the fin" designates the dimension of the fin measured in the radial direction. The term “width of the fin” designates the dimension of the fin measured in the axial direction.

The thickness of the flange corresponds to the distance, measured in the axial direction, between the internal face and the external face.

The flange may have a thickness comprised between 5 and 30 mm, better still between 7 and 20 mm, better still between 10 and 15 mm, for example of the order of 13 mm.

The flange may have a diameter of between 50 and 300 mm, better still between 75 and 200 mm, better still between 100 and 150 mm, for example of the order of 136 mm.

The width of the fin, in particular the width of the part of the fin which extends into the opening, may be greater than the thickness of the flange. The fins can thus protrude from the flange, including at the level of the openings. These overruns allow the formation of coolant turbulence at the fins and thus improves cooling.

Alternatively, the width of the fins may be less than the thickness of the flange.

The term “width of a part of a fin which extends over the outer face of the flange” designates the width of the part of the fin which extends from the flange. This width does not include the thickness of the flange.

The width of a portion of a fin which extends over the outer face of the flange may be between 1 and 15 mm, better still between 2 and 10 mm, better still between 3 and 8 mm, for example of the order of 5mm.

The width of a portion of a fin which extends over the outer face of the flange may be between 0 and 20% of the diameter of the flange, better still between 1 and 15%, better still between 3 and 10%, for example the order of 3.7% of the diameter of the flange.

The width of a portion of a fin which extends over the outer face of the flange may be between 3 and 300% of the thickness of the flange, better between 10 and 200%, better between 15 and 100%, better between 20 and 75%, better still between 30 and 50%, for example of the order of 38% of the thickness of the flange.

The height of a fin can be between 10 and 35% of the diameter of the flange, better still between 15 and 30%, better still between 18 and 27%, for example of the order of 25% of the diameter of the flange.

The height of a fin can be between 10 and 60 mm, better between 20 and 50 mm, better between 30 and 40 mm, for example of the order of 35 mm.

The height of the part of the fin which extends into the opening may be between 1 and 15 mm, better still between 3 and 10 mm, better still between 5 and 8 mm, for example of the order of 7 mm.

The height of the part of the fin which extends into the opening may be greater than 30% of the height of the opening measured in the radial direction, better still greater than 50%, better still greater than 70%, for example the order of 100%.

In the case where the height of the part of the fin which extends into the opening is of the order of 100% of the height of the opening measured in the radial direction, the fin completely crosses the opening. . The thickness of a fin can be between 0 and 20% of the diameter of the flange, better still between 1 and 15%, better still between 3 and 10%, for example of the order of 3.7% of the diameter of the flange.

The thickness of a fin can be between 1 and 15 mm, better between 2 and 10 mm, better between 3 and 8 mm, for example of the order of 5 mm.

The thickness of a fin may be less than the width of the opening, measured in the circumferential direction, through which it extends. This makes it possible to leave space in the openings, in particular on either side of the fin, to allow the flow of the cooling fluid.

In the case of an L-shaped fin, the two parallelepipedal parts can have different heights and/or widths.

Each fin may comprise a lower face and an upper face which both extend in planes perpendicular to the flange. The lower face is closer to the axis of rotation X of the electrical machine than the upper face.

The underside of a fin may be located at a distance from the axis of rotation X of the machine of at least 20%, better still at least 30%, better still at least 40%, for example l order of 45% of the diameter of the flange.

The underside of a fin may be located at a distance from the axis of rotation X of the machine of at most 70%, better still at most 60%, better still at most 50%, for example l order of 45% of the diameter of the flange.

The underside of a fin can be located at a distance from the axis of rotation X between 30 and 90 mm, better between 40 and 80 mm, better between 50 and 70 mm, for example of the order of 60 mm .

The upper face of a fin can be located at a distance from the axis of rotation X of the machine of at least 60%, better still at least 70%, better still at least 80%, for example l 82% of the diameter of the flange.

The upper face of a fin may be located at a distance from the axis of rotation X of the machine of at most 100%, better still at most 90%, better still at most 85%, for example l 82% of the diameter of the flange.

The upper face of a fin can be located at a distance from the axis of rotation X of between 70 and 135 mm, better still between 80 and 125 mm, better still between 100 and 115 mm, for example of the order of 112 mm . At least one fin can extend along a master plane perpendicular to the inner and outer faces of the flange. At least one fin can extend along a master plane inclined with respect to the axis of rotation X of the electric machine.

A fin extending along a master plane perpendicular to the inner and outer faces makes it possible to form a turbulent flow on one of its faces.

A fin extending along a master plane inclined with respect to the axis of rotation X of the electric machine makes it possible to ensure that the flow of the cooling fluid better matches the shape of the fin. This limits turbulence on the upper surface of the fin, which reduces aerodynamic losses.

A fin can be inclined at an angle relative to the inner and outer faces of the flange comprised between 0 and 90°, better still between 10 and 80°, better still between 20 and 70°, better still between 30 and 60°, for example l order of 45°.

At least one fin may extend along a master plane inclined with respect to a radial plane containing the axis of rotation of the machine.

Such inclinations of the fins make it possible to optimize the flow of air for a given operating point. For example, the fins can be tilted so that the flow is optimized for the rotational speed at which the electrical machine in operation is the hottest.

At least one third of the fins can extend along a master plane perpendicular to the inner and outer faces of the flange, better still at least half, better still at least two thirds, better all the fins can extend along a master plane perpendicular to the inner and outer faces of the flange.

At least one third of the fins can extend along a master plane inclined with respect to the axis of rotation of the machine, better still at least half, better still at least two thirds, better still all the fins can extend along a master plane inclined with respect to the axis of rotation of the machine.

At least one third of the fins can extend along a master plane inclined with respect to a radial plane, better at least half, better at least two thirds, better all the fins can extend along a master plane inclined with respect to to a radial plane.

All the inclined fins can have the same inclination. As a variant, at least two fins can have different inclinations. For example 2, 3, 4, 5 fins can have different inclinations. In another embodiment, all the fins can have different inclinations.

You can tilt only the leading edge of a fin. Thus, only the leading edge of the fin(s) can be inclined relative to the axis of rotation of the machine and/or relative to a radial plane.

Openings

The flange according to the invention may comprise at least two openings, in particular at least two openings uniformly distributed around the central bore.

In a particular embodiment, the flange may comprise six uniformly distributed openings and the angle between the middles of two consecutive openings may be of the order of 60°. In another particular embodiment, the flange may comprise three uniformly distributed openings and the angle between the middles of two consecutive openings may be of the order of 120°.

Each opening may have a height, measured in the radial direction, of between 5 and 25 mm, better still between 10 and 20 mm, better still between 12 and 15 mm, for example of the order of 13 mm.

Each opening may have a width, measured in the circumferential direction, of between 3 and 45 mm, better still between 5 and 40 mm, better still between 7 and 35 for example of the order of 11 mm or 30 mm.

The flange may comprise at least two openings of substantially identical shape.

Each opening can be the image of another opening by an angle rotation between 30° and 180°.

In a variant embodiment, the flange may comprise at least two openings of different shapes.

The openings can have an oblong, rectangular or even oval shape.

The flange may include at least one fin extending over the entire height of the opening in the radial direction, the fin dividing in particular the opening into two sub-openings which may be substantially identical.

The fin can thus pass right through an opening. Such an arrangement improves the mechanical holding of the flange. Radial grooves

The inner face of the flange may comprise at least one radial groove extending radially from the edge in the direction of the central bore of the flange.

Such radial grooves allow the coolant to exit the flange and be directed towards the coil heads in order to cool them.

At least one groove, better at least half of the grooves, better all the grooves, can be located substantially at the same circumferential position as the opening or openings, in particular the same circumferential position as the center of the openings. As a variant at least one groove, better at least half of the grooves, better all the grooves, can be located at circumferential positions distinct from the openings.

The presence of a radial groove allows the cooling fluid to circulate efficiently beyond the radius of the flange and thus improves the cooling of the coil heads. The grooves force the flow in radial directions using the centrifugation created by the rotation of the flange.

When the flange and the machine rotate, a vortex may be created. For example, the cooling fluid which is in the groove can be sucked by centrifugal effect and can be projected radially on the coil heads to cool them.

The cooling fluid can be supplied to the grooves through the openings in the flange. As a variant, the cooling fluid can be supplied to the grooves via axial channels formed in the rotor mass.

The flow rate of coolant escaping from the grooves and/or the local or global characteristics of the cooling may depend on the rotational speed of the machine and the dimensions of the grooves.

The grooves arranged on the inner face can be against the rotor, in particular against the rotor mass.

At least one groove may extend along a rectilinear elongation axis L. All the grooves can extend along a straight elongation axis L. The axis or axes of elongation L can be radial.

The length of the radial grooves may be less than the distance, measured radially, between the edge and the outside diameter of the central bore. The cross section of the groove may be constant over at least one third of the length, better over at least half the length, better over at least two thirds of the length, better over its entire length.

Alternatively, the cross section of the groove may not be constant.

For example, the groove may widen towards the edge. In this case, the closer you get to the edge of the flange, the more the cross section of the groove increases. Such a groove shape allows, by venturi effect, that the speed of the cooling fluid at the outlet of the groove is lower than at the inlet. Such a shape allows a more global and homogeneous cooling.

As a variant, the groove can converge in the direction of the edge. In this case, the closer you get to the edge of the flange, the more the cross section of the groove narrows. With such a groove shape, the speed of the cooling fluid at the outlet is greater than at the inlet. This makes it possible to create localized rotating cooling, in particular close to the coil heads.

The outer face can have the same number of grooves as openings.

At least one groove can open into an opening.

In a particular embodiment, all the grooves can open into an opening. An aperture may be in fluid communication with only one groove. Alternatively, an aperture may be in fluid communication with multiple grooves.

The groove(s) can be oriented along an axis of symmetry of the opening into which they open.

The groove(s) may be remote from the opening(s).

The groove or grooves may not be in fluid communication with the openings of the flange which carries them. The grooves may be in fluid communication with the openings of a flange disposed at another end of the rotor.

Rotor

The invention also relates to an electric machine rotor, comprising a rotor mass and at least one flange as defined above. In one embodiment, the subject of the invention is a rotor comprising a rotor mass and two flanges as defined previously, each disposed at one end of the rotor mass.

The invention also relates, according to another of its aspects, to a rotor of an electrical machine rotating around an axis of rotation X, the rotor comprising a rotor mass and at least one flange as defined above, the mass rotor comprising at least one housing intended to receive a magnet, the housing comprising at least one recess, at least one recess of one of the housings being at least partially superimposed on at least one opening of the flange when the rotor is observed according to axis of rotation X of the machine.

As a variant, the openings can be superimposed on recesses made in the rotor mass and arranged elsewhere than in the housings of the magnets, for example recesses dedicated specifically to the circulation of the cooling fluid.

In cross section, the openings have an extent substantially equal to the extent of the housing to which they are partially superimposed.

The rotor can comprise a first and a second flange as described above. The two flanges can be angularly offset by an angle P relative to each other around the axis of rotation.

The angle P can be equal to the angle between two poles of the electrical machine. The angle P can be between 50 and 80°, better still between 45 and 75°, between 40 and 70°, for example of the order of 60°.

The rotor can be configured to provide cross circulation of the cooling fluid within the rotor mass.

In particular, the fluid can circulate in the recesses of the rotor mass which are angularly offset around the axis of rotation, the recesses in which the fluid circulates towards the rear preferably alternating with those in which the fluid circulates towards the front, the recesses being preferably parallel and associated with respective poles of the rotor.

The machine may comprise a cooling fluid supply to the flanges, the fluid supplying the first flange circulating from the latter through the rotor mass via at least one recess towards the second flange, and the fluid supplying the second flange flowing from the latter to the first flange by at least one recess of the rotor mass.

Preferably, the first and second flanges are identical and angularly offset so as to supply different recesses, the recesses traversed by the fluid circulating from the first flange to the second flange being for example made within the odd poles, and those traversed by the fluid in the opposite direction, being for example located within the even poles.

The inner face of the first flange and the inner face of the second flange may each comprise at least one groove extending radially from the edge in the direction of the central bore of the flanges, at least one groove of the first flange being at least partially superimposed on at least one opening of the second flange when the rotor is observed along the axis of rotation X of the machine.

The cooling fluid enters the rotor through the openings of the first flange and exits through the grooves of the second flange. It is thus possible to impose a direction on the flow of cooling fluid.

The grooves preferably open opposite the coil heads of the stator, in order to allow the projected fluid to cool them. The cooling fluid that supplies the second flange joins the first flange by flowing through the recesses and then is ejected from the first flange via one of the grooves to cool the coil heads. Similarly, the cooling fluid which supplies the first flange joins the second flange by flowing through the recesses and then is ejected from the second flange via one of the grooves to cool the coil heads.

The cooling fluid can be a gas, for example air.

electric machine

The invention also relates to an electric machine comprising a stator and a rotor as defined above.

The stator may comprise a stator mass comprising notches provided between teeth, each notch receiving one or more winding conductors. The machine can be used as a motor or as a generator. The machine can be reluctance. It can constitute a synchronous motor or, as a variant, 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.

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. The housing is, for example, water-cooled.

The notches can be at least partially closed. A partially closed notch makes it possible to create an opening at the level of the air gap, which can be used, for example, for the installation of electrical conductors for filling the notch. A partially closed notch is in particular made between two teeth which each have pole shoes at their free end, which close the notch at least in part.

Alternatively, the notches can be completely closed. By “fully closed notch”, is meant notches which are not open radially towards the air gap.

In one embodiment, at least one notch, or even each notch, can be continuously closed on the air gap side 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 bridges of material closing the notches. The material bridges may be integral 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 notches are then continuously closed on the side of the air gap by the bridges of material coming from a single 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 outwards. 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.

The stator may comprise coils arranged in a distributed manner in the slots, having in particular electrical conductors arranged in a row in the slots. By “distributed”, we mean that at least one of the coils passes successively through two non-adjacent slots.

The electrical conductors may not be arranged in the notches loosely but in an orderly manner. They are stacked in the slots in a non-random manner, being for example arranged in rows of aligned electrical conductors. The stack of electrical conductors is for example a stack according to a hexagonal network in the case of electrical conductors of circular cross-section.

The stator may include electrical conductors housed in the slots. Electrical conductors at least, see a majority of electrical conductors, can be pin-shaped, U-shaped or I-shaped. The pin can be U-shaped ("U-pin" in English) or straight, being in form of I ("I-pin" in English).

The electrical conductors can thus form a distributed winding. The winding may not be concentrated or tooth wound.

In a variant embodiment, the stator has a concentrated winding. The stator may include teeth and coils disposed on the teeth. The stator can thus be wound on teeth, in other words with undistributed winding.

The stator teeth may include pole shoes. Alternatively, the stator teeth are devoid of pole shoes.

The stator may include an outer carcass surrounding the yoke. The teeth of the stator can be made with a stack of magnetic laminations, each covered with an insulating resin, in order to limit the losses by induced currents.

Manufacturing process

Process for manufacturing a flange as defined above, the flange(s) possibly being produced by foundry and/or machining.

Brief description of the drawings

The invention can be better understood on reading the following description, non-limiting examples of implementation thereof, and on examining the attached drawing, in which:

[Fig la] figure la is a perspective view of the outer face of a flange according to the invention,

[Fig 1b] Figure 1b is a perspective view of the inner face of the flange of Figure la,

[Fig le] figure le is a cross-sectional diagram of an electrical machine comprising two flanges as illustrated in figures la and 1b,

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

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

[Fig 2c] figure 2c is a view similar to figure le of an alternative embodiment,

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

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

[Fig 4] Figure 4 is a front view of a rotor plate attached to the inner face of the flange of Figures 3a and 3b,

[Fig 5] Figure 5 is a schematic partial profile view of a rotor comprising the flange of Figure 3 a, [Fig 6] Figure 6 is a front view of the outer face of a flange according to another embodiment of the invention,

[Fig 7] Figure 7 is a view similar to Figure la of an alternative embodiment,

[Fig 8] Figure 8 is a view similar to Figure la of an alternative embodiment,

[Fig 9a] figure 9a is a diagram seen in profile of a fin of a flange according to the invention,

[Fig 9b] Figure 9b is a view similar to Figure 9a of an alternative embodiment, and

[Fig 9c] Figure 9c is a view similar to Figure 9a of an alternative embodiment, and

[Fig 9d] Figure 9d is a view similar to Figure 9a of an alternative embodiment.

detailed description

In the figures and in the rest of the description, the same references represent identical or similar elements.

There is illustrated in Figures la, 1b and a flange 10 according to the invention. The flange has a central bore 13, an inner face 11, an outer face 12 and a radially outer edge 17 extending between the inner face 11 and the outer face 12.

The flange 10 has openings 14, for example it has six openings 14. In the illustrated embodiment, the openings 14 are all identical and are evenly distributed around the central bore 13.

On its outer face 12, the flange 10 comprises fins 15 extending partially into the openings 14. Each fin 15 comprises a part 15a which extends into the opening 14 and a part 15b which extends from the outer face 12. The fins 15 do not extend completely through the openings 14. In the example illustrated, the fins 15 have a thickness of the order of 5 mm, a width of the order of 5 mm and a height of the order of 20 mm. In this variant embodiment, the flange 10 has grooves 16 on its inner face 11. The grooves 16 are arranged at the same circumferential position as the fins 15 have on the outer face 12. The grooves 16 extend from the edge 17 from the flange to the periphery of the openings 14 so that they open there and that fluid communication between them is ensured. The grooves 16 extend along a rectilinear elongation axis L. The grooves 16 are for example of cross-section of constant shape over their entire height, in particular of rectangular shape.

Figure le illustrates an electric machine 1 arranged in a casing 6 comprising a rotor 2 and an external stator 3. The stator 3 makes it possible to generate a rotating magnetic field for driving the rotor 2 in rotation, within the framework of a synchronous motor , and in the case of an alternator, the rotation of the rotor induces an electromotive force in the electrical conductors of the stator 3.

The rotor 1 represented in figure 1e comprises a magnetic rotor mass 4 extending axially along the axis of rotation X of the rotor, this rotor mass being formed by a stack of magnetic rotor laminations stacked along the axis X, the laminations being for example identical and superimposed exactly. The magnetic laminations are preferably made of magnetic steel. All grades of magnetic steel can be used.

The rotor mass 4 has a central opening for mounting on a shaft 5. The shaft can, in the example considered, be made of a non-magnetic material, for example non-magnetic stainless steel or aluminum, or on the contrary be magnetic.

According to the invention, the rotor 1 comprises two flanges 10, as described above, each disposed at one end of the rotor mass 4. The use of such flanges in an electric machine allows cooling, in particular cooling by air, effective.

The rotor mass, and in particular the rotor laminations, comprises housings intended to receive permanent magnets.

Recesses 41 in which the cooling fluid can circulate are made in the rotor mass 4. The recesses 41 can be arranged in the housings of the permanent magnets. As a variant, the recesses 41 can be axial channels arranged elsewhere than in the housings of the permanent magnets. The recesses 41 are at least partially superimposed on the openings 14 of the flange when the rotor is observed along the axis of rotation X of the electric machine. Thus, the cooling fluid can enter the rotor mass through the openings 14.

The circulation of the cooling fluid in the electric machine 1 has been illustrated in FIG. particular by the parts 15a of the fins which extend in the openings 14, through the openings 14 towards the recesses 41 made in the rotor mass 4. The cooling fluid can thus cool the heart of the rotor mass 4.

As illustrated in FIG. 1e, the outlets of the grooves 16 are oriented towards the ends of the coils 30 of the stator. Part of the cooling fluid contained in the casing can be directed by centrifugal force into the grooves 16 then towards the coil heads 30 to cool them.

There is illustrated in Figures 2a, 2b and 2c a flange 10 according to another embodiment of the invention. In this variant, the flange has three openings 14. The flange has on its outer face 12 three fins 15 which partially extend into the openings 14 and three fins 15' which do not extend into an opening. On its inner face 11, the flange has three grooves 16 arranged at the same circumferential positions as the fins 15' which do not extend into an opening. In this embodiment, the grooves 16 extend from the edge 17 of the flange and do not open into the openings 14. The grooves 16 extend along a straight elongation axis L.

There is illustrated in Figure 2c the circulation of the cooling fluid in an electrical machine comprising a first flange 10a and a second flange 10b according to the variant embodiment of Figures 2a and 2b. The two flanges 10a and 10b can be angularly offset by an angle P of the order of 60° relative to each other around the axis of rotation.

The flanges 10a and 10b are placed against the rotor mass so that the grooves 16 and the openings 14 face the recesses 41 formed in the rotor mass when the rotor is observed along the axis of rotation X of the electric machine. The first 10a and second 10b flanges are identical and angularly offset so as to supply different recesses 41. When the machine is running, the cooling fluid which supplies the second flange 10b joins the first flange 10a by flowing through the openings 14 of the first flange then through the recesses 41 then is ejected from the first flange 10a via the grooves 16 to cool the coil heads 30. Similarly, the cooling fluid which supplies the first flange 10a joins the second flange 10b by flowing through the openings 14 of the second flange, then through the recesses 41 then is ejected of the second flange via the grooves 16 to cool the coil heads 30. The direction of circulation of the cooling fluid in the rotor is thus imposed.

There is illustrated in Figures 3a, 3b, 3c and 3d another embodiment of the invention. In this variant, the fins 15 all pass through one of the openings 14. Each fin 15 divides the opening 14 through which it extends into two symmetrical sub-openings 14a and 14b.

There is illustrated in Figure 4 a sheet 42 of the rotor mass. The sheet 42 has housings 43 for magnets 44. The magnets 44 do not occupy all the space of the housings 43 so that recesses 41 are made in the housings.

The flange 10 is placed against the plate 42 of the rotor mass in such a way that the openings 14 are partially superimposed on the recesses 41 formed in the housings 43 of the magnets.

The cooling fluid which is directed towards the openings 14 can thus flow in the recesses 41 to reach the opposite flange and cool the heart of the rotor mass.

There is illustrated in Figure 5 an example of an electric machine rotor comprising a flange 10 according to Figures 3a or 3b.

In this variant, the fins 15 have a height L of the order of 25 mm. Figures 6 to 8 illustrate alternative embodiments in which the flange 10 comprises six openings 14 and six fins 15 on its outer face 12. Each fin 15 comprises a part 15a which extends into one of the openings 14 and a part 15b which extends from the outer face 12 of the flange 10.

In the embodiment of Figure 6, the part 15b of the fin which extends from the outer face 12 of the flange 10 does not extend to the edge 17 of the flange. The height ha of the part 15b of the fin 15 which extends from the outer face 12, measured in the radial direction, is less than the radial distance between the edge 17 of the flange and the peripheral edge 140 of the opening 14 closest to the edge.

The width of the part 15b of the fin 15 which extends from the outer face 12, measured in the axial direction, is of the order of 5 mm.

In the embodiment of Figure 7, the part 15b of the fin which extends from the outer face 12 of the flange 10 extends from the edge 17 of the flange 10 to the periphery of an opening 14. The height ha of the part 15b of the fin 15 which extends from the outer face 12, measured in the radial direction, is substantially equal to the radial distance between the edge 17 of the flange and the peripheral edge 140 of the opening. 14 closest to the slice. The height ha of the part 15b of the fin 15 which extends from the outer face 12, measured in the radial direction, is of the order of 46.4 cm.

In the embodiment of Figure 8, the part 15b of the fin which extends from the outer face 12 of the flange 10 does not extend to the edge 17 of the flange. The height ha of the part 15b of the fin 15 which extends from the outer face 12, measured in the radial direction, is less than the radial distance between the edge 17 of the flange and the peripheral edge 140 of the opening 14 closest to the slice.

The width la of the part 15b of the fin 15 which extends from the outer face 12, measured in the axial direction, is of the order of 10 mm.

There is illustrated in Figures 9a, 9b and 9c, the different possibilities of orientations of the fins 15 with respect to the axis of orientation X of the electric machine.

In the example of Figure 9a, the master plane of the fin 15 is substantially perpendicular to the outer face 12 of the flange. The flow of cooling fluid is shown schematically by the arrows 150. The fin 15 is placed at the entrance to a recess 41 forming a channel in the rotor mass. Part of the cooling fluid is oriented towards the recess 4L It can be seen that the flow of cooling fluid is turbulent on one of the faces of the fin, for example on the upper face 151.

In the example of FIG. 9b, the directing plane P of the fin 15 is inclined with respect to the axis of rotation X. The cooling fluid 150 is directed towards the recess 41 creating a channel in the rotor mass. It can be seen that there is no turbulence near the fin 15. In the example of FIG. 9c, the directing plane of the fin 15 is inclined at an angle a with respect to the axis of rotation X and the fin 15 comprises a rectilinear portion 152 and a curved portion 153 around an axis of curvature oriented perpendicular to a radial plane containing the axis of rotation X of the electrical machine. Such a shape of fin 15 makes it possible to further improve the quantity of cooling fluid which is oriented in the recess 41.

In the example of Figure 9d, the fin has two straight portions 154, 155. The two rectilinear portions 154, 155 form between them an angle 0 of the order of 135°. The invention is not limited to what has just been described. For example, the flange may have a different number of openings. It may also include fins and/or openings of different sizes.

Claims

22 Claims

1. flange (10) of an electrical machine rotor rotating around an axis of rotation X, comprising an inner face (11) facing a rotor mass (4), an outer face (12) opposite the inner face, a radially outer edge (17) extending between the inner face and the outer face and a central bore (13), the flange comprising:

- one or more through openings (14) between the inner face and the outer face, and

- at least one fin (15) extending at least partially into the opening, the inner face (11) comprising at least one radial groove (16) extending radially from the edge (17) in the direction of the bore center (13) of the flange (10).

2. flange (10) of an electric machine rotor rotating around an axis of rotation X, comprising an inner face (11) facing a rotor mass (4), an outer face (12) opposite the inner face, a radially outer edge (17) extending between the inner face and the outer face and a central bore (13), the flange comprising:

- at least one fin (15) extending at least partially into the opening, at least one fin being L-shaped.

3. Flange according to one of the two preceding claims, the fin(s) (15) being formed integrally with the flange (10).

4. Flange according to one of the three preceding claims, at least one fin (15) may be of substantially flat shape, and extending along a master plane.

5. Flange according to the preceding claim, the master plane of the fin (15) comprising the axis of rotation X of the machine.

6. Flange according to any one of the preceding claims, at least one fin (15) extending along a master plane perpendicular to the inner (11) and outer (12) faces of the flange (10) and / or at least one fin (15) extending along a master plane inclined relative to the axis of rotation X of the electric machine.

7. Flange according to any one of the preceding claims, at least one fin (15) extending along a master plane inclined relative to a radial plane containing the axis of rotation of the machine.

8. Flange according to any one of the preceding claims, comprising at least two openings (14) uniformly distributed around the central bore (13).

9. Flange according to any one of the preceding claims, comprising at least two openings (14) of substantially identical shape.

10. Flange according to any one of the preceding claims, comprising at least one fin (15) extending over the entire height of the opening (14) in the radial direction, the fin dividing in particular the opening into two under -openings (14a, 14b) which may be substantially identical.

11. Flange according to any one of claims 2 to 10, the inner face (11) comprising at least one radial groove (16) extending radially from the edge (17) in the direction of the central bore (13) of the flange (10).

12. Flange according to the preceding claim, at least one groove (16) opening into an opening (14).

13. Flange according to claim 10, the groove or grooves (16) being spaced from the opening or openings (14).

14. Rotor of an electric machine rotating about an axis of rotation X, the rotor comprising a rotor mass (4) and at least one flange (10) according to any one of the preceding claims, the rotor mass comprising at least one housing (43) intended to receive a magnet (44), the housing comprising at least a recess (41), at least one recess of one of the housings being at least partially superimposed on at least one opening (14) of the flange when one observes the rotor along the axis of rotation X of the electrical machine.

15. Rotor according to the preceding claim, the rotor comprising a first and a second flange (10a, 10b) according to any one of claims 1 to 12, the two flanges being angularly offset by an angle P relative to one another. the other around the X axis of rotation.

16. Rotor according to the preceding claim, the inner face (12) of the first flange (10a) and the inner face (12) of the second flange (10b) each comprising at least one groove (16) extending radially from the edge ( 17) towards the bore center (13) of the flanges, at least one groove of the first flange being at least partially superimposed on at least one opening (14) of the second flange when the rotor is observed along the axis of rotation X of the electric machine.