ROTOR FOR AN AXIAL FLUX ELECTRIC MACHINE, AND METHODS FOR ASSEMBLING AND REMOVING SUCH A ROTOR

Disclosed is a rotor including: a body including a hub from which a plurality of arms extend; a plurality of magnet blocks disposed between the arms; and a circular ring disposed at the periphery of the rotor. One of an inner face of the circular ring and an outer face of each of the magnet blocks has a first depression, the other having a complementary shape. The rotor includes a plurality of holders each arranged between the body and a magnet block so as to urge the magnet block against the circular ring with the circular ring and the magnet block nested at the first depression.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention generally relates to the field of axial flux electric machines.

It relates more specifically to a rotor for an axial flux electric machine, said rotor having a disc shape centered about a longitudinal axis and comprising:a body comprising a hub from which a plurality of arms extend;a plurality of magnet blocks, each magnet block being disposed between two adjacent arms;a circular ring disposed at the periphery of the rotor and surrounding the magnet blocks.

The invention has a particularly advantageous application in electric engines for electric or hybrid motor vehicles.

It also relates to methods for assembling and removing such a rotor.

Description of the Related Art

An axial flux electric machine generally comprises two stators and one rotor, air gaps separating these two types of elements. The rotor carries a series of permanent magnets or magnet blocks, while a series of coils is carried by the stators.

When the coils are powered by an electric current, the rotor, which is secured to the output shaft of the engine, is subjected to a torque resulting from the magnetic field (the magnetic flux created being an axial flux for an axial flux electric machine).

Conventionally, to assemble such a rotor, on the one hand, a body is manufactured in disc shape and having notches, and on the other hand, the magnet blocks. The magnet blocks are then implemented in the notches provided for this purpose.

To secure the magnet blocks to the body, they are conventionally adhered to the latter. Using adhesive however has several disadvantages.

First, the adhesives used are thermosetting adhesives. Once injected, the rotor must thus be heated at a very high temperature in a furnace and subjected to a holding pressure, which represents both a certain material and energy cost. The series manufacture of adhesive-based rotors is therefore expensive.

Furthermore, an adhesive layer adds an additional link in the chain of dimensions, which complexifies the design of the rotor and does not guarantee the obtaining of an identical air gap difference (which necessarily has a damaging impact on the magnetic performance).

In addition, once adhered, the magnet blocks can no longer be disconnected from the body. The adhesion therefore limits the options for maintaining the rotor, a faulty magnet block not being able, for example, to be replaced by a new magnet block. With the adhesive not being recyclable, once adhered, the rotor or its elements are not either.

Adhesive-free rotors have been proposed, like for example in document FR3027468. In these rotors, the notches are radially open outwards, such that they do not surround the magnet blocks at the periphery of the rotor. The magnet blocks are secured to the body by the implementation, by force, of a pre-urged circular fret surrounding the assembly constituted of the body and of the magnet blocks.

The implementation of a fret is however complex as it requires a great accuracy both with the manufacturing of parts and the application of the force by a specific press to implement the fret. Like adhesive, this solution therefore remains difficult to industrialize.

In addition, once the fret is implemented, the rotor is not longer removable (or is very difficult to remove), which limits, once again, the options of maintaining or recycling parts.

SUMMARY OF THE INVENTION

In this context, a rotor for an axial flux electric machine is proposed, such as defined in the introduction, wherein it is provided that one of an inner face of the circular ring and an outer face of each of the magnet blocks has a first depression, the other having a complementary shape; and wherein the rotor comprises a plurality of holding means, each arranged between the body and one of the magnet blocks so as to urge said magnet block against the circular ring with the circular ring and said magnet block nested at said first depression.

Thus, thanks to the invention, the rotor is assembled without adhesive nor fretting. The holding means, in engagement with the hollow circular ring, ensure the cohesion of the rotor.

Not fixing the magnet blocks to the body by adhering or by fretting makes it possible to do without specific machines, and thus reduce the manufacturing costs. This also simplifies the series manufacture of the rotor, by removing complex steps, such as heating at a high temperature or fretting.

Furthermore, the rotor according to the invention makes it possible to consider the separation of the magnet blocks from the body, and thus to facilitate the maintenance and the recycling of the rotor, or only some of its elements.

What is more, in a preferred embodiment, the magnet blocks can make small translations in radial directions. The holding means thus play the role of dampers when the magnet blocks move towards the center of the rotor. The urges that the magnet blocks undergo are thus reduced, which makes it possible to limit the risks of breaking and increase their longevity.

Other advantageous and non-limiting features of the rotor according to the invention, taken individually or according to all the technically possible combinations, are as follows:said holding means are removable;said circular ring is resilient;each of said holding means is disposed in a housing provided in the body, said housing comprising an opening designed to introduce said holding means in said housing, said opening having a size less than that of said holding means;said holding means are springs or clips or fretted pin gauges;each of said holding means is surrounded between an inner face of a magnet block and the body;each of said holding means is eccentric with respect to the thickness of the body about the longitudinal axis;each of said arms comprises two second depressions or protrusions opposite one another and extending in length in an extension direction of said arm, and each of said magnet blocks has two side faces, each comprising a third depression or protrusion, of shape complementary to that of the second depression or protrusion of the arm with which said side face is in contact;each of said second depressions or protrusions has a depth or respectively a height, towards the side face with which said second depression or protrusion is in contact, increasing by moving closer to the longitudinal axis;each of said magnet blocks comprises a plurality of single magnets, glued or fretted in a peripheral support;anti-vibration means are provided between each magnet block and the hub;said body is made of aluminum.

The invention also proposes a method for assembling a rotor such as described above comprising the following steps:insertion of the magnet blocks between the arms;implementation of the circular ring around the magnet blocks;activation of the holding means between the body and the magnet blocks so as to urge the magnet blocks against the circular ring.

This assembling method makes it possible to assemble the rotor without fretting nor adhering. Indeed, before the implementation of the holding means, the magnet blocks are slightly closer to the body, which leaves a sufficient clearance to implement the circular ring, without force.

The invention finally proposes a method for removing a rotor such as described above, comprising the following steps:deactivation of the holding means so as to separate the magnet blocks from the circular ring;removal of the circular ring from the periphery of the magnet blocks;removal of at least one of the magnet blocks from between the arms.

This removal method makes it possible, for example, to be able to separate one of the elements of the rotor, with the aim of repairing it or replacing it. Generally, this removal method facilitates the maintenance of the rotor.

Naturally, the different features, variants and embodiments of the invention can be associated with one another according to various combinations, insofar as they are not incompatible or exclusive from one another.

DETAILED DESCRIPTION

A rotor for an axial flux electric machine according to the invention, such as represented inFIG.1and referenced in its entirety by the reference1, mainly has a disc shape centered about a longitudinal axis A1. In this case, the rotor1has, more specifically, a flattened cylinder shape, the thickness of which, dimension about the longitudinal axis1, is a lot less than the diameter, dimension along a radial direction, perpendicular to the longitudinal axis A1. The longitudinal axis A1corresponds, in this case, to the axis of rotation of the rotor1when it rotates within an electric machine.

InFIG.1, the rotor1is secured by screws2to a flange3and to an engine shaft4. The rotor1is, for example, comprised between two disc-shaped stators, also centered about the longitudinal axis A1. When the stators rotate the rotor1, the latter drives the engine shaft4. The electric machine comprising the rotor1and the stators thus produces a torque.

The rotor1has two opposite circular faces. The distance between these two circular faces about the longitudinal axis A1defines the thickness of the rotor1. Below, the periphery of the rotor1is called its outer part, opposed to its central part, located at the longitudinal axis A1. Thus, the periphery of the rotor1corresponds to a circular perimeter located at a distance from the longitudinal axis A1.

AsFIG.1shows, the rotor1comprises:a body10;a plurality of magnet blocks20disposed at the periphery of the body10;a circular ring30surrounding the magnet blocks20, the circular ring30and the magnet blocks20being nested at a first depression50(which cannot be seen inFIG.1);a plurality of holding means40of the magnet blocks20(which cannot be seen inFIG.1).

The body10comprises a hub11and a plurality of arms12extending from the hub11. The hub11constitutes the central part of the body10and has a central recessing enabling the fixing of the flange3and of the engine shaft4. In this case, the arms12extend in directions substantially radial with respect to the longitudinal axis A1. Such as represented in the figures, the arms12taper towards the periphery of the rotor1.

The arms12are all identical and regularly distributed around the hub11, so as to be separated, two-by-two, by a space.

As appears inFIG.2, each pair of two adjacent arms12delimits a trapezoidal-shaped notch13. Two arms12are, in this case, adjacent when they are not separated by another arm. The notch13is, in this case, radially open towards the periphery of the rotor1.

In this case, the body10is preferably made of aluminum, which makes it possible to reduce the manufacturing costs of the rotor1. As is described below, the use of an aluminum body1, more fragile than a body made of composite material, is made possible by the fact that the magnet blocks20are not fixed to the arms12. The arms12thus undergo almost no radial urges when the rotor1is in operation.

The body10is, for example, made by a stack of aluminum sheets of a thickness less than or equal to one millimeter. In a variant, it can be provided that the body10of the rotor1is made of another metal material or of composite materials, for example, fiber compounds buried in a resin.

The magnet blocks20are distributed in free spaces between the arms12.

Each magnet block20is disposed between two adjacent arms12. Each magnet block20is thus disposed in a notch13, the shape of the notches being adapted to the shape of the magnet blocks20. One single magnet block20is disposed between each pair of adjacent arms12. The rotor1therefore comprises as many magnet blocks20as arms12, for example16of each, like in the example illustrated inFIG.1.

AsFIG.3more specifically shows, each magnet block20has, in this case, a mainly trapezoidal shape. Each magnet block20thus comprises two main faces of substantially trapezoidal shapes and two side faces21. Within the rotor1, each side face21faces an arm12. Each magnet block20also comprises an inner face22, facing, within the rotor1, the hub11. Finally, each magnet block20comprises an outer face23. The outer face23is located at the periphery of the rotor1and mainly has a circular arc-shaped curvature.

In this case, asFIG.3more specifically shows, each magnet block20comprises a plurality of single magnets25inserted inside a peripheral support26. The single magnets25are, for example, adhered or fretted in the peripheral support26. In this case, the side21, inner22and outer23faces of the magnet blocks20are formed by the peripheral support26. The peripheral support26is made of an antimagnetic material, for example made of polymer.

To ensure the holding of the magnet blocks20in the body10about the longitudinal axis A1, each magnet block20is sandwiched between two adjacent arms12by means of slider connections, in this case, of the groove-rib type, extending towards the periphery of the rotor1.

To make slider connections, each arm12comprises two second depressions or protrusions14, opposite one another and extending in length in an extension direction of the arm12, i.e. towards the periphery of the rotor1. Each magnet block20itself comprises, at each of its side faces21, a third depression or protrusion24of shape complementary to the second depression or protrusion14. The third depressions or protrusions24are, in this case, formed in the peripheral support26.

In this case, for each arm12, the second depressions or protrusions14are of the same type.

In practice, asFIG.2shows, each arm12carries on its two opposite sides (those located facing the magnet blocks20), two ribs, the profiles of which have rectangular sections (these ribs form the two second depressions or protrusions14). Correspondingly, asFIG.3shows, the two side faces21of each magnet block20each have a hollow groove designed to be inserted in the rib of the corresponding arm12. In a variant, the arms12could comprise grooves and the magnet blocks20could comprise ribs.

Advantageously, providing ribs on the arms12and grooves on the magnet blocks20makes it possible to reinforce the arms12.

AsFIGS.2and3show, the dimension of the second depressions or protrusions14and of the third depressions or protrusions24in a plane orthogonal to the longitudinal axis A1, i.e. in this case, the depth of the ribs and the height of the grooves along the orthoradial dimension of the rotor, progressively increases by moving closer to the longitudinal axis A1. This variation of size of the nesting makes it possible to improve the holding of the magnet blocks20about the longitudinal axis A1, while limiting the risks of the arms12breaking.

As represented inFIG.1, the circular ring30has a mainly annular shape. The circular ring30is disposed at the periphery of the rotor1. The circular ring30surrounds the magnet blocks20, and more specifically, the assembly formed by the body10and the magnet blocks20. The circular ring30is in contact by its inner face31with the outer faces23of the magnet blocks20.

The circular ring30is, in this case, made of aluminum. Aluminum is indeed cheaper than the carbon fiber materials conventionally used for circular rings. Using an aluminum circular ring30is in particular made possible as, as is described below, the implementation of the circular ring30does not require fretting.

In addition, it is, in this case, provided that the circular ring30is only in contact with the magnet blocks20. This means that the circular ring30is not in contact with the body10. For this, the magnet blocks20slightly project from the notches13at the periphery of the rotor1. The whole urge exerted by the circular ring30is thus applied to the magnet blocks20, which improves their holding in the notches13.

In a variant, the circular ring30could come into contact with the magnet blocks20and with the body10.

In this case, the circular ring30is resilient. This means, in this case, that the circular ring30can slightly be deformed when the rotor rotates, accelerates or decelerates suddenly.

Preferably, the circular ring30is profiled in this sense that it has a cross-section of invariable shape all along its contour. Its implementation on the magnet blocks20is thus facilitated.

The holding of the circular ring30on these magnet blocks is not done by a forceful mounting or via the use of adhesive or of mounted fixing means. On the contrary, it is done by engagement of geometric shapes.

In this case, the inner face31of the circular ring30or the outer faces23of the magnet blocks20have a first depression50. The outer faces23of the magnet blocks20, or respectively the inner face31of the circular ring30, have a shape complementary to the first depression50. Thus, the inner face31of the circular ring30or the outer faces23of the magnet blocks20are designed to be nested in one another at the first depression50.

When the outer faces23of the magnet blocks20have a first depression50, this thus means that each outer face23has a first depression50, which is preferably identical on all the outer faces23.

Generally, a complementary shape does not mean, in this case, that the face in question, i.e. that inner face31of the circular ring30or the outer face23of the magnet block20, necessarily has a protrusion of shape complementary to the first depression50, even if this can be the case. As appears in the examples illustrated inFIGS.4and5, the face in question can have a straight rectilinear profile (without raised part) while being designed to be nested, by its dimensions, in the first depression50.

In the example illustrated inFIG.4, the first depression50is located at the inner face31of the circular ring30and the magnet block20has a complementarily-shaped raised part. This case is that of the rotor1represented inFIG.1. In this case, the circular ring30comprises a recess, the concavity of which is oriented towards the magnet blocks20, i.e. towards the longitudinal axis A1. In this case, the outer face23of the magnet block20is in contact with the bottom of the recess formed in the inner face31of the circular ring30.

In the example illustrated inFIG.5, the first depression50is located on the outer face23of the magnet block20and the circular ring30has a complementary shape. However, it can be provided that the circular ring30has a height about the longitudinal axis A1greater than that of the first depression50(the size of the inner face31does not thus correspond to that of the first depression50), and that the inner face31of the circular ring30has a complementarily-shaped rib projecting to the first depression50provided in the outer face23of the magnet block20.

In a variant, the circular ring could comprise both a recess surrounding the outer face of the magnet block and a projecting rib designed to be nested in an indentation of the outer face of the magnet block. Such a variant corresponding to a combination of the two examples illustrated inFIGS.4and5.

The holding means40make it possible, in engagement with the circular ring30, to hold the magnet blocks20in the notches13, i.e. to secure them to the body10.

In this case, asFIG.1shows, each holding means40is associated with a respective magnet block20. In other words, it is provided, in this case, with one holding means40per magnet block20. The rotor1therefore comprises as many holding means40as magnet blocks. In a variant, several holding means could be provided per magnet block.

It is observed, inFIG.7or8, that each holding means40is arranged between the body10and a magnet block20. More specifically, each holding means40is, in this case, arranged between the hub11, at the base of two adjacent arms12, and the inner face22of the magnet block20.

Each holding means40is arranged so as to urge the associated magnet block20against the circular ring30. Thus, the holding means40makes it possible to hold the circular ring30and the magnet block20nested at the first depression50.

In this case, if the radial symmetry plane of a magnet block30is considered (comprising the longitudinal axis A1), each holding means40is disposed so as to exert a force on this magnet block in a direction comprised in this radial symmetry plane and oriented towards the periphery of the rotor1.

To generate these forces, the holding means40are, in this case, preferably pre-urged. This means that they have undergone, at the time of their mounting on the body10, a resilient deformation due to a compression about a radial axis with respect to the longitudinal axis A1. The urges that they generate on the magnet blocks20therefore come from return forces. For more reliability, the holding means40are preferably made in one piece. The holding means40are, for example, made of metal.

Thanks to the resilience of the holding means40and of the circular ring30, when the rotor1is in operation and that radial forces, directed towards the center or the periphery of the rotor1, are exerted on the magnet blocks20, the latter can make small movements, while being permanently held on either side. The engagement of the holding means40and of the circular ring30makes it possible to dampen these movements. This freedom of movement transferred to the magnet blocks20makes it possible to limit jolts in the acceleration phase and in the deceleration phase and thus to limit the risks of the magnet blocks20breaking.

In this case, the holding means40are removable. This means that the holding means40can be disconnected from the rotor1, for example using a specific tool, while leaving the magnet blocks20in the notches13. Removable holding means40offer numerous maintenance options, for example, by enabling a removal of the rotor1with a reuse of its elements.

Preferably, the inner face22of the magnet blocks20each comprise a reinforcement designed to receive an end of the holding means40.

In this case, the holding means40are, for example, springs, typically helical springs, or clips or fretted pin gauges. Spring blades could also be used. Preferably, all the holding means40of the rotor1are of the same type.

In a first embodiment of the rotor1, shown inFIGS.1,6and7, the holding means40are clips. As represented inFIG.6, the holding means40are more specifically circlips mainly having the shape of an open ring comprising, on either side of the opening, two orifices41designed to handle the holding means40using a specific tool (for example, circlip pliers). The resilient deformation of the holding means40is, in this case, a reduction of the diameter of the clips, i.e. a reduction of the opening of the ring.

In a second embodiment of the rotor1, represented inFIG.8, the holding means40are helical compression springs, the winding axis of the spirals of which corresponds to a radial direction. The resilient deformation of the holding means40is, in this case, a reduction of the length of the springs.

In a third embodiment (not represented), the holding means are fretted pin gauges. A pin gauge is, for example, a conic or truncated part forcefully arranged by its end having the smallest diameter between the body10and the magnet block20. By inserting the pin gauge between the hub11and the inner face23of a magnet block20, the magnet block20is progressively urged against the circular ring30. The resilient deformation of the holding means40is, in this case, a slight compression of the volume of the pin gauge.

When the holding means are springs or clips (even pin gauges), the latter can be positioned in housings60provided in the body10. A housing60is, in this case, a recessing, made in the body10, the dimensions of which are adapted to receive at least one part of a holding means40. The housings60are provided in the body10and more specifically, in the hub11. The housings60open towards the magnet blocks20, at an outlet oriented towards the periphery of the rotor1, such that the holding means40can apply an urge on the magnet blocks20.

In the first embodiment, as represented inFIGS.6and7, the housing60is located in the hub11and has a disc shape centered on an axis parallel to the longitudinal axis A1.

In the first embodiment, shown inFIGS.6and7, each housing60comprises, in addition to its outlet, an opening61specifically designed to introduce the holding means40in the housing60. AsFIGS.6and7show, the openings61are circular. The openings61are provided in the hub11at one of the two circular faces of the rotor1. To prevent the holding means40from exiting the housing60unpredictably, the opening61has a size less than that of the holding means40. In other words, the opening61has a size less than that of the housing60itself. In this case, the resilience of the holding means40is used to compress it and to introduce it through the opening61. Once in the housing60, the holding means40expand.

In the case of the second embodiment represented inFIG.8, the housing60has the shape of a cylinder extending in a radial direction. The housing60is thus hollow in the outer face of the hub11which faces the associated magnet block. In a variant not represented, it can be provided that the housing60of the spring further comprises a rectangular-shaped opening enabling a side insertion of the spring when the latter is compressed.

In this case, the holding means40are eccentric with respect to the thickness of the body10. In other words, the holding means40are not located at the middle of the thickness of the body10, but are closer to one of the two circular faces of the rotor1. This positioning of the holding means40can be particularly seen inFIG.8. In this case, the housings60themselves are eccentric with respect to the thickness of the body10. Due to this eccentricity, each holding means40applies a force on the associated magnet block20, which improves the holding of the magnet block20in the notch13.

Now, in reference toFIGS.6to8, two embodiments of a method for assembling the rotor1are described.

In these two embodiments, the assembly method comprises the following main steps:e1—insertion of the magnet blocks20between the arms12(an anti-vibration seal or a resilient strip, for example made of foam, being optionally adhered to the inner face22of the magnet blocks20before their insertion between the arms12;e2—implementation of the circular ring30around the magnet blocks20;e3—activation of the holding means40between the body10and the magnet blocks20so as to urge the magnet blocks20against the circular ring30.

The first embodiment of the assembly method is illustrated inFIGS.6and7. In this first embodiment, the circular ring30has a hollow recess in its inner face and the holding means40are clips.

This first embodiment is characterized by the fact that the holding means40are implemented after the implementation of the circular ring30around the magnet blocks20.

During a preliminary step, the magnet blocks20are assembled by adhering or fretting the single magnets25in the peripheral support26.

Then, during the insertion step e1, the magnet blocks20are inserted between the arms12of the body10in substantially radial directions. The insertion is guided by the slider connections between the arms12and the side faces21of the magnet blocks20. The magnet blocks20are inserted until their inner faces22are in contact with the hub11.

Thus, the following implementation step e2, the circular ring30can be implemented without forcing, typically without fretting. Indeed, the circular ring30is, in this case, slightly wider than the perimeter of the magnet blocks20when the latter are flattened against the hub11of the body10. In this configuration, a clearance between the perimeter of the magnet blocks20and the circular ring30makes it possible to implement the latter easily. It is only during the step e3 of activating the holding means40that the magnet blocks20come back into contact with the circular ring30.

The circular ring30is thus removable, in this case, in particular with respect to the body10, in the sense where the latter is adapted to be reversibly mounted around the magnet blocks20.

The activation step e3 comprises, in this case, the following substeps:gripping and compression of the holding means40by a tool;insertion of the holding means40in the housing60through the opening61;removal of the tool and deployment of the holding means40, which leads to the urging of the magnet block20against the circular ring30.

In this case, the tool is, for example, designed to grip a clip at the two orifices41. By moving closer to these two orifices41, the diameter of the clip decreases, which makes it possible to position it in the housing60. By removing the tool, the clip expands and abuts against the inner face23of the magnet block20.

During the activation step e3, the magnet blocks20are nested with the circular ring30at the depression50, that this is provided on the circular ring30as inFIG.5or that this is provided on the outer faces23of the magnet blocks20as inFIG.4.

In a variant, it can be provided that the holding means are fretted pin gauges and that the activation step consists of inserting the pin gauges between the body and the magnet blocks, for example by means of a press. Also, in a variant, it can be provided that the holding means are springs introduced laterally in the housings through the rectangular openings.

A second embodiment of the assembly method is illustrated byFIG.8. In this second embodiment, the holding means40are springs. This second embodiment is distinguished from the first embodiment, in that the holding means40are positioned in the housings60before the implementation of the magnet blocks20.

Thus, before the step e1 of inserting the magnet blocks20, the assembly method according to this second embodiment comprises a preliminary step of placing the holding means40on the body10.

Once inserted between the arms of the body10, the magnet blocks20are compressed against the hub11(the springs are therefore also compressed). This makes it possible, as in the first embodiment, to implement the circular ring30without forcing, thanks to a clearance between the perimeter of the magnet blocks20and the circular ring30.

The step e3 of activating the holding means40thus consists of relaxing the compression of the magnet blocks20such that the holding means40can expand.

Now, a method for removing the rotor1is described, comprising the following main steps:e4—deactivation of the holding means40so as to separate the magnet blocks20from the circular ring30;e5—removal of the circular ring30from the periphery of the magnet blocks20;e6—removal of at least one of the magnet blocks20from between the arms12.

When the rotor1has been assembled according to the first embodiment, the deactivation step e4 comprises the following substeps:gripping and compression of the clip by a tool, which leads to the de-urging of the magnet block20;removal of the holding means40from the housing60through the opening61.

The magnet blocks20can then be moved closer to the body10, typically until putting the inner face23in contact with the hub11, to produce the clearance between the perimeter of the magnet blocks20and the circular ring30. During the step e5 of removing the circular ring30, the latter can thus be removed without difficulty.

When the rotor1has been assembled according to the second embodiment, the deactivation step e4 comprises the compression of the magnet blocks20, and therefore the holding means40, against the body10towards the longitudinal axis A1to produce the clearance mentioned above.

Then, during the following removal step e6, one, more or all the magnet blocks20can be removed.

This removal method has numerous advantages, such as being able to replace or repair an element of the rotor1or being able to separate and sort the different elements with a view to recycling them.

The present invention is not at all limited to the embodiments described and represented, but a person skilled in the art will know how to provide any variant according to the invention.