A rotor for an axial flux electric machine and methods for assembling and disassembling such a rotor.

Abstract

The present invention relates to a rotor (1) comprising a body (10) including a hub (11) from which a number of arms (12) extend, a number of magnet blocks (20) arranged between the arms (12), and a circular ring (30) arranged on the periphery of the rotor, one of the inner surface of the circular ring and the outer surface of each of the magnet blocks having a first recess and the other having a complementary shape, characterized in that the rotor comprises a number of retaining means (40), each of which is arranged between the body and the magnet blocks to bias the magnet blocks against the circular ring, the circular ring and the magnet blocks nested in the first recess.

Description

[Technical Field]

[0001] The present invention relates generally to the field of axial flux electric machines.

[0002] The invention more particularly relates to a rotor for an axial flux electric machine, said rotor having a disk shape centered on a longitudinal axis, a body including a hub having a plurality of arms extending therefrom; a plurality of magnet blocks, each magnet block being disposed between two adjacent arms; a circular ring disposed on the periphery of the rotor and surrounding the magnet block;

[0003] The invention has particularly advantageous application in electric engines for electric or hybrid vehicles.

[0004] The present invention also relates to methods for assembling and disassembling such rotors. [Background technology]

[0005] Axial-flux electric machines generally contain two stators and one rotor with an air gap separating the two types of elements. The rotor carries a series of permanent magnets or magnet blocks, and a series of coils are carried by the stator.

[0006] When the coil is powered by an electric current, the rotor, which is fixed to the output shaft of the engine, experiences a torque due to the magnetic field (the magnetic flux produced is the axial flux in an axial flux electric machine).

[0007] Conventionally, to assemble such a rotor, on the one hand, a disk-shaped body is manufactured with notches, and on the other hand, it contains magnet blocks, which are then inserted into the notches provided for this purpose.

[0008] To secure the magnet block to the body, the magnet block is usually glued to the body, however, there are some drawbacks to using glue.

[0009] First, the adhesive used is a thermosetting adhesive. Therefore, once injected, the rotor must be heated to very high temperatures in a furnace and subjected to holding pressure, which represents a constant material and energy cost. Therefore, continuous production of adhesive-based rotors is expensive.

[0010] Furthermore, the adhesive layer adds an additional link in the dimensional chain, which complicates the rotor design and does not guarantee obtaining the same air gap difference (which inevitably has a negative impact on magnetic performance).

[0011] Furthermore, once glued, the magnet blocks cannot be separated from the main body. Therefore, gluing limits options for maintaining the rotor; for example, a failed magnet block cannot be replaced with a new one. If the adhesive is not recyclable, the rotor or its components, once glued, cannot be recycled.

[0012] Adhesive-free rotors have been proposed, such as in French Patent No. 3027468. In these rotors, the notches open radially outward so as not to enclose the magnet blocks at the rotor periphery. The magnet blocks are fixed to the body by force-mounting pre-tensioned circular frets that enclose the assembly consisting of the body and magnet blocks. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] French Patent No. 3027468 Summary of the Invention [Problem to be solved by the invention]

[0014] However, the mounting of the frets is complex, requiring high precision both in the manufacturing of the components and in the application of the force required by the specific press to mount the frets. Therefore, like adhesives, this solution remains difficult to industrialize.

[0015] Furthermore, once the frets are implemented, the rotor is no longer removable (or is very difficult to remove), which again limits the maintenance or recycling options for the part. [Means for solving the problem]

[0016] In this regard, a rotor for an axial-flux electric machine as defined in the introduction is proposed, provided that one of the inner surface of the circular ring and the outer surface of each magnet block has a first recess and the other has a complementary shape, and the rotor includes a plurality of retaining means, each retaining means being arranged between the body and one of the magnet blocks so as to urge the magnet block against the circular ring when the circular ring and the magnet block are nested in the first recess.

[0017] Thus, thanks to the invention, the rotor is assembled without adhesives and without fretting. The retaining means engages with the hollow circular ring to ensure tight contact of the rotor.

[0018] By not fixing the magnet blocks to the body by adhesive or fretting, it is possible to do this without special machinery, thus reducing manufacturing costs. This also simplifies serial manufacturing of the rotor by eliminating complex steps such as high-temperature heating or fretting.

[0019] Furthermore, the rotor according to the invention makes it possible to consider the separation of the magnet blocks from the body, thus facilitating the maintenance and recycling of only some of the rotor or its elements.

[0020] Furthermore, in a preferred embodiment, the magnet blocks are capable of small radial translations, so that the retaining means act as a damper when the magnet blocks move towards the centre of the rotor, thus reducing the forces experienced by the magnet blocks, limiting the risk of breakage and making it possible to extend their lifespan.

[0021] Other advantageous, non-limiting features of the rotor according to the invention, taken individually or according to all technically possible combinations, are: the retaining means is removable; the circular ring is elastic; each of said retaining means is disposed in a housing provided in the body, said housing including an opening designed to introduce said retaining means into said housing, said opening having a size smaller than that of said retaining means; said retaining means being a spring, clip or fret pin gauge; Each of the retaining means is enclosed between the inner surface of the magnet block and the body; each of said retaining means being eccentric relative to the thickness of the body about the longitudinal axis; each of the arms includes two second recesses or protrusions facing each other and extending in the extension direction of the arm; and each of the magnet blocks has two side surfaces each including a third recess or protrusion having a shape complementary to the shape of the second recess or protrusion of the arm with which the side surface is in contact; each of the second recesses or protrusions has a depth or height, respectively, that increases toward the longitudinal axis toward the side that the second recesses or protrusions contact; each of said magnet blocks includes a plurality of unitary magnets bonded or fretting to a peripheral support; Vibration isolation means are provided between each magnet block and the hub; The body is made of aluminum.

[0022] The present invention also provides a method for assembling a rotor as described above, comprising the steps of: Inserting a magnet block between the arms; mounting the circular ring around a magnet block; and c) actuating the retaining means between the body and the magnet block to bias the magnet block against the circular ring.

[0023] This assembly method allows the rotor to be assembled without fretting or sticking: in fact, before the mounting of the holding means, the magnet block is slightly close to the body, leaving a gap sufficient to mount the circular ring without force.

[0024] The present invention relates to a method for removing a rotor as described above, comprising the steps of: stopping the retaining means to separate the magnet block from the circular ring; removing the circular ring from the periphery of the magnet block; and removing at least one of the magnet blocks from between the arms.

[0025] This method of removal makes it possible, for example, to separate one of the rotor's elements in order to repair or replace it. In general, this method of removal makes it easier to maintain the rotor.

[0026] Naturally, the different features, variants and embodiments of the invention can be associated with one another according to various combinations, unless they are mutually incompatible or exclusive.

[0027] The following description with reference to the accompanying drawings is given by way of non-limiting example to make it clear what the invention consists of and how it can be achieved. [Brief explanation of the drawings]

[0028] In the accompanying drawings:

[0029] [Figure 1]1 is a schematic diagram of a rotor according to the present invention;

[0030] [Figure 2] FIG. 2 is a schematic perspective view of a portion of the body of the rotor of FIG. 1.

[0031] [Figure 3] FIG. 2 is a schematic perspective view of a magnet block of the rotor of FIG. 1.

[0032] [Figure 4] 2 is a schematic cross-sectional view of the peripheral portion of the rotor of FIG. 1 along plane AA.

[0033] [Figure 5] 10 is a schematic cross-sectional view of a peripheral portion of a variant of an embodiment of a rotor according to the present invention.

[0034] [Figure 6] FIG. 2 is a schematic perspective view of the holding means of the rotor of FIG. 1 before mounting.

[0035] [Figure 7] FIG. 7 is a schematic perspective view of the holding means of FIG. 6 after mounting.

[0036] [Figure 8] FIG. 10 is a schematic perspective view of a holding means of a variant of an embodiment of a rotor according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] The rotor for an axial-flux electric machine according to the invention, as shown in Figure 1 and generally designated by the numeral 1, has a generally disk-like shape centered on a longitudinal axis A1. In this case, the rotor 1 has, more specifically, a flat cylindrical shape, the thickness of which is much smaller about the longitudinal axis A1 than along a radial direction perpendicular to the longitudinal axis A1. The longitudinal axis A1 corresponds in this case to the axis of rotation of the rotor 1 as it rotates in the electric machine.

[0038] In Figure 1, rotor 1 is fixed to flange 3 and engine shaft 4 by screws 2. Rotor 1 is contained between, for example, two disk-shaped stators, also centered on longitudinal axis A1. When the stators rotate rotor 1, rotor 1 drives engine shaft 4. Thus, an electric machine including rotor 1 and stators generates torque.

[0039] The rotor 1 has two opposing circular surfaces, the distance between which, centered on the longitudinal axis A1, defines the thickness of the rotor 1.

[0040] In the following, the periphery of the rotor 1 will be referred to as its outer part, which is opposite to its central part located on the longitudinal axis A1. The periphery of the rotor 1 therefore corresponds to the circular outer periphery located away from the longitudinal axis A1.

[0041] As shown in FIG. 1, the rotor 1 is The main body 10 and A plurality of magnet blocks 20 arranged on the periphery of the main body 10; a circular ring 30 surrounding the magnet block 20, the circular ring 30 and the magnet block 20 nested in a first recess 50 (not visible in FIG. 1); and a plurality of holding means 40 for the magnet blocks 20 (not visible in FIG. 1).

[0042] The body 10 includes a hub 11 and a plurality of arms 12 extending from the hub 11. The hub 11 forms the central portion of the body 10 and has a central recess that allows the flange 3 and the engine shaft 4 to be fixed thereto. In this case, the arms 12 extend substantially radially relative to the longitudinal axis A1. As shown in the figure, the arms 12 taper toward the outer periphery of the rotor 1.

[0043] The arms 12 are all identical and are regularly distributed around the hub 11, whereby they are spaced apart two by two.

[0044] As can be seen in Figure 2, each pair of two adjacent arms 12 defines a trapezoidal notch 13. In this case, the two arms 12 are adjacent when not separated by another arm. The notch 13 in this case opens radially towards the periphery of the rotor 1.

[0045] In this case, the body 10 is preferably made of aluminum, which reduces the manufacturing costs of the rotor 1. As will be explained below, the fact that the magnet blocks 20 are not fixed to the arms 12 allows the use of an aluminum body 10, which is weaker than a body made of composite material. The arms 12 are therefore subjected to little radial bias when the rotor 1 is in operation.

[0046] The body 10 is made, for example, by stacking aluminum sheets with a thickness of less than one millimeter. Alternatively, it can be provided that the body 10 of the rotor 1 is made of another metallic material or a composite material, for example a fiber compound embedded in a resin.

[0047] The magnet blocks 20 are distributed in the free space between the arms 12. Each magnet block 20 is disposed between two adjacent arms 12. Therefore, each magnet block 20 is disposed in a notch 13, and the shape of the notch is adapted to the shape of the magnet block 20. One magnet block 20 is disposed between each pair of adjacent arms 12. Therefore, similar to the example shown in FIG. 1 , the rotor 1 includes the same number of magnet blocks 20 as the number of arms 12, for example, 16 magnet blocks 20 for each of the arms 12 and the magnet blocks 20.

[0048] As shown more specifically in Figure 3, each magnet block 20 in this case has a primarily trapezoidal shape. Thus, each magnet block 20 includes two substantially trapezoidal main surfaces and two side surfaces 21. Within the rotor 1, each side surface 21 faces an arm 12. Each magnet block 20 also includes an inner surface 22 that faces the hub 11 within the rotor 1. Finally, each magnet block 20 includes an outer surface 23. The outer surface 23 is located on the outer periphery of the rotor 1 and has a primarily arcuate curvature.

[0049] In this case, as shown more specifically in Figure 3, each magnet block 20 includes a plurality of single magnets 25 inserted inside a peripheral support 26. The single magnets 25 are, for example, glued or fretting to the peripheral support 26. In this case, the side surface 21, the inner surface 22 and the outer surface 23 of the magnet block 20 are formed by the peripheral support 26. The peripheral support 26 is made of a diamagnetic material, for example made of a polymer.

[0050] To ensure retention of the magnet blocks 20 within the body 10 around the longitudinal axis A1, each magnet block 20 is sandwiched between two adjacent arms 12 by means of slider connections, in this case of groove rib type, which extend towards the periphery of the rotor 1.

[0051] To effect the slider connection, each arm 12 includes two second recesses or protrusions 14 facing each other and extending longitudinally in the extension direction of the arm 12, i.e. towards the outer periphery of the rotor 1. Each magnet block 20 itself includes, on each of its side surfaces 21, a third recess or protrusion 24 of a shape complementary to the second recesses or protrusions 14. The third recesses or protrusions 24 are in this case formed in the peripheral support 26.

[0052] In this case, for each arm 12, the second recesses or protrusions 14 are of the same type.

[0053] In practice, as shown in Figure 2, each arm 12 carries on its two opposing sides (sides arranged to face the magnet block 20) ​​two ribs whose profile has rectangular portions (these ribs form two second recesses or protrusions 14). Correspondingly, as shown in Figure 3, the two sides 21 of each magnet block 20 each have a hollow groove designed to be inserted into the rib of the corresponding arm 12. In a variant, the arm 12 can include the grooves and the magnet block 20 can include the ribs.

[0054] Advantageously, the provision of ribs on the arm 12 and grooves in the magnet block 20 makes it possible to reinforce the arm 12 .

[0055] 2 and 3, the dimensions of the second recesses or protrusions 14 and the third recesses or protrusions 24 in the plane perpendicular to the longitudinal axis A1, i.e., in this case, the depth of the ribs and the height of the grooves along the orthogonal dimensions of the rotor, gradually increase as they approach the longitudinal axis A1. This change in nest size allows for improved retention of the magnet block 20 around the longitudinal axis A1 while limiting the risk of breakage of the arms 12.

[0056] 1, the circular ring 30 has a generally annular shape. The circular ring 30 is arranged on the periphery of the rotor 1. The circular ring 30 surrounds the magnet block 20, more specifically, the assembly formed by the body 10 and the magnet block 20. The circular ring 30 contacts the outer surface 23 of the magnet block 20 with its inner surface 31.

[0057] The circular ring 30 is made of aluminum in this case. Aluminum is actually cheaper than the carbon fiber material traditionally used for circular rings. As will be explained below, the implementation of the circular ring 30 does not require fretting, making the use of an aluminum circular ring 30 particularly feasible.

[0058] Additionally, in this case, the circular ring 30 is only in contact with the magnet blocks 20, which means that the circular ring 30 is not in contact with the body 10. For this reason, the magnet blocks 20 protrude slightly from the notches 13 on the periphery of the rotor 1. The full force exerted by the circular ring 30 is therefore applied to the magnet blocks 20, which improves their retention in the notches 13.

[0059] In a variant, the circular ring 30 can be in contact with the magnet block 20 and the body 10 .

[0060] In this case, the circular ring 30 is elastic, which means that in this case the circular ring 30 can deform slightly when the rotor rotates, accelerates or decelerates suddenly.

[0061] Preferably, the circular ring 30 is shaped in this sense to have a cross section of constant shape all along its contour, thus making it easier to mount it on the magnet block 20.

[0062] The retention of the circular ring 30 to these magnet blocks is not achieved by forceful attachment or by the use of adhesive or attached fastening means, but rather by geometric engagement.

[0063] In this case, the inner surface 31 of the circular ring 30 or the outer surface 23 of the magnet block 20 has a first recess 50. The outer surface 23 of the magnet block 20 or the inner surface 31 of the circular ring 30, respectively, has a shape complementary to the first recess 50. Therefore, the inner surface 31 of the circular ring 30 or the outer surface 23 of the magnet block 20 are designed to nest within each other at the first recess 50.

[0064] Therefore, when the outer surface 23 of the magnet block 20 has a first recess 50 , this means that each outer surface 23 has a first recess 50 that is preferably identical on all outer surfaces 23 .

[0065] In general, complementary shape does not mean that the face in question, i.e., in this case, the inner surface 31 of the circular ring 30 or the outer surface 23 of the magnet block 20, necessarily has a protrusion of a shape complementary to the first recess 50, even if it does. As can be seen in the example shown in Figures 4 and 5, the face in question can have a straight linear profile (without raised portions), while being designed by its dimensions to nest within the first recess 50.

[0066] In the example shown in Figure 4, the first recess 50 is located on the inner surface 31 of the circular ring 30, and the magnet block 20 has a complementary shaped raised portion. This is the case for the rotor 1 shown in Figure 1. In this case, the circular ring 30 includes a recess that is oriented toward the magnet block 20, i.e., toward the longitudinal axis A1. In this case, the outer surface 23 of the magnet block 20 contacts the bottom of the recess formed in the inner surface 31 of the circular ring 30.

[0067] 5, the first recess 50 is located on the outer surface 23 of the magnet block 20, and the circular ring 30 has a complementary shape. However, the circular ring 30 may have a height around the longitudinal axis A1 that is greater than the height of the first recess 50 (and therefore the size of the inner surface 31 does not correspond to the size of the first recess 50), and the inner surface 31 of the circular ring 30 may have a rib of a complementary shape that protrudes into the first recess 50 provided on the outer surface 23 of the magnet block 20.

[0068] In a variation, the circular ring can include both a recess surrounding the outer surface of the magnet block and a protruding rib designed to nest in the recess in the outer surface of the magnet block. Such a variation corresponds to a combination of the two examples shown in Figures 4 and 5.

[0069] The retaining means 40 engage with the circular ring 30 to make it possible to retain the magnet block 20 in the notch 13 , i.e. to fix the magnet block to the body 10 .

[0070] 1 shows, each holding means 40 is associated with a respective magnet block 20. In other words, in this case, one holding means 40 is provided for each magnet block 20. The rotor 1 therefore includes the same number of holding means 40 as there are magnet blocks. In a variant, several holding means can be provided per magnet block.

[0071] 7 or 8, it can be seen that each holding means 40 is arranged between the main body 10 and the magnet block 20. More specifically, each holding means 40 is arranged in this case between the hubs 11 at the bases of two adjacent arms 12 and the inner surface 22 of the magnet block 20.

[0072] Each holding means 40 is arranged to bias the associated magnet block 20 against the circular ring 30. The holding means 40 thus make it possible to hold the magnet block 20 nested in the circular ring 30 and the first recess 50.

[0073] In this case, if a radial plane of symmetry of the magnet block 20 is considered (containing the longitudinal axis A1), each holding means 40 is contained in this radial plane of symmetry and is arranged to apply a force to this magnet block in a direction oriented towards the outer periphery of the rotor 1.

[0074] To generate these forces, the holding means 40 is preferably pre-biased in this case. This means that when attached to the body 10, it undergoes elastic deformation by compression about a radial axis relative to the longitudinal axis A1. The biasing force acting on the magnet block 20 therefore results from a return force. For greater reliability, the holding means 40 is preferably made in one piece. The holding means 40 is made, for example, of metal.

[0075] Thanks to the elasticity of the retaining means 40 and the circular ring 30, when the rotor 1 is in operation, radial forces directed towards the centre or periphery of the rotor 1 are exerted on the magnet blocks 20, which are able to make small movements while being permanently held on both sides. The engagement of the retaining means 40 with the circular ring 30 makes it possible to damp these movements. This freedom of movement transmitted to the magnet blocks 20 makes it possible to limit shocks during acceleration and deceleration phases, and therefore the risk of damaging the magnet blocks 20.

[0076] In this case, the holding means 40 is removable, which means that it can be detached from the rotor 1, for example using a specific tool, while leaving the magnet blocks 20 in the notches 13. A removable holding means 40 offers multiple maintenance options, for example by allowing its elements to be reused and the rotor 1 to be removed.

[0077] Preferably, the inner surfaces 22 of the magnet blocks 20 each include a reinforcement designed to receive an end of the retaining means 40 .

[0078] In this case, the retaining means 40 are, for example, springs, typically helical springs, or clips or fret pin gauges. Spring blades can also be used. Preferably, all retaining means 40 of a rotor 1 are of the same type.

[0079] In a first embodiment of the rotor 1 shown in Figures 1, 6 and 7, the retaining means 40 is a clip. As shown in Figure 6, the retaining means 40 is more specifically a circlip having mainly the shape of an open ring with two orifices 41 on either side of the opening designed to handle the retaining means 40 using a specific tool (for example circlip pliers). The elastic deformation of the retaining means 40 in this case results in a reduction in the diameter of the clip, i.e. a reduction in the opening of the ring.

[0080] In a second embodiment of the rotor 1 shown in Figure 8, the retaining means 40 is a helical compression spring, the axis of winding of which corresponds to the radial direction. The elastic deformation of the retaining means 40 in this case is a reduction in the length of the spring.

[0081] In a third embodiment (not shown), the holding means is a fret pin gauge. The pin gauge is, for example, a conical or truncated section forcibly placed by its end having the smallest diameter between the body 10 and the magnet block 20. By inserting the pin gauge between the hub 11 and the inner surface 22 of the magnet block 20, the magnet block 20 is gradually biased against the circular ring 30. The elastic deformation of the holding means 40 in this case is a slight compression of the volume of the pin gauge.

[0082] If the retaining means is a spring or a clip (or even a pin gauge), the retaining means can be arranged in a housing 60 provided in the body 10. The housing 60 is in this case a recess formed in the body 10, the dimensions of which are adapted to receive at least a part of the retaining means 40. The housing 60 is provided in the body 10, more particularly in the hub 11. The housing 60 opens towards the magnet blocks 20 with an outlet directed towards the periphery of the rotor 1 so that the retaining means 40 can apply a force to the magnet blocks 20.

[0083] In the first embodiment, as shown in FIGS. 6 and 7, the housing 60 is disposed within the hub 11 and has a disk shape centered on an axis parallel to the longitudinal axis A1.

[0084] In the first embodiment shown in Figures 6 and 7, each housing 60 includes, in addition to its outlet, an opening 61 specifically designed to introduce the retaining means 40 into the housing 60. As Figures 6 and 7 show, the opening 61 is circular. The opening 61 is provided in the hub 11 on one of the two circular faces of the rotor 1. To prevent the retaining means 40 from unpredictably exiting the housing 60, the opening 61 has a size smaller than that of the retaining means 40. In other words, the opening 61 has a size smaller than that of the housing 60 itself. In this case, the elasticity of the retaining means 40 is used to compress the retaining means 40 and introduce it through the opening 61. Once inside the housing 60, the retaining means 40 expands.

[0085] In the second embodiment shown in Figure 8, the housing 60 has the shape of a radially extending cylinder. The housing 60 is therefore hollow at the outer surface of the hub 11 facing the associated magnet block. In a variant not shown, the spring housing 60 may further comprise a rectangular opening that allows for lateral insertion of the spring when it is compressed.

[0086] In this case, the retaining means 40 are eccentric with respect to the thickness of the body 10. In other words, the retaining means 40 are not located in the center of the thickness of the body 10, but are closer to one of the two circular faces of the rotor 1. This positioning of the retaining means 40 can be seen in particular in Figure 8. In this case, the housing 60 itself is eccentric with respect to the thickness of the body 10. Due to this eccentricity, each retaining means 40 exerts a force on the associated magnet block 20, which improves the retention of the magnet block 20 in the notch 13.

[0087] Two embodiments of a method for assembling the rotor 1 will now be described with reference to FIGS.

[0088] In these two embodiments, the assembly method includes the following main steps: e1 - inserting the magnet block 20 between the arms 12 (before insertion between the arms 12, an anti-vibration seal or elastic strip, e.g. made from foam, is optionally glued to the inner surface 22 of the magnet block 20), e2—mounting the circular ring 30 around the magnet block 20; e3—activating the retention means 40 between the body 10 and the magnet block 20 so as to bias the magnet block 20 against the circular ring 30.

[0089] A first embodiment of the assembly method is shown in Figures 6 and 7. In this first embodiment, the circular ring 30 has a hollow recess on its inner surface and the retaining means 40 is a clip.

[0090] This first embodiment is characterized in that the holding means 40 are mounted after mounting the circular ring 30 around the magnet block 20 .

[0091] During a preliminary step, the magnet block 20 is assembled by gluing or fretting a single magnet 25 within a peripheral support 26 .

[0092] Then, in an insertion step e1, the magnet blocks 20 are inserted approximately radially between the arms 12 of the body 10. The insertion is guided by the slider connections between the arms 12 and the side surfaces 21 of the magnet blocks 20. The magnet blocks 20 are inserted until their inner surfaces 22 come into contact with the hub 11.

[0093] Therefore, in the following implementation step e2, the circular ring 30 can be mounted without forcing, typically without fretting. Indeed, in this case, the circular ring 30 is slightly wider than the outer periphery of the magnet block 20 when the latter is flattened against the hub 11 of the body 10. In this configuration, the gap between the outer periphery of the magnet block 20 and the circular ring 30 makes the latter easy to implement. Only during step e3, in which the holding means 40 is activated, does the magnet block 20 come into contact with the circular ring 30 again.

[0094] The circular ring 30 is therefore in this case detachable with respect to the body 10 in particular in the sense that the body 10 is adapted to be reversibly mounted around the magnet block 20 .

[0095] The actuating step e3 in this case comprises the following sub-steps: gripping and compressing the retaining means 40 with a tool; inserting the retaining means 40 into the housing 60 through the opening 61; Removing the tool and deploying the retaining means 40, thereby biasing the magnet block 20 against the circular ring 30.

[0096] In this case, the tool is designed to grip the clip, for example, at the two orifices 41. By approaching these two orifices 41, the diameter of the clip is reduced, which makes it possible to position the clip in the housing 60. By removing the tool, the clip expands and abuts against the inner surface 22 of the magnet block 20.

[0097] During actuation step e3, the magnet block 20 is nested with the circular ring 30 in the recess 50, which is provided on the circular ring 30 as in FIG. 5, or which is provided on the outer surface 23 of the magnet block 20 as in FIG.

[0098] In a variant, it can be provided that the retaining means is a fret pin gauge and that the actuation step consists of inserting the pin gauge between the body and the magnet block, for example by pressing. Also, in a variant, it can be provided that the retaining means is a spring introduced laterally into the housing through the rectangular opening.

[0099] A second embodiment of the assembly method is shown in Figure 8. In this second embodiment, the retaining means 40 is a spring. This second embodiment is distinguished from the first embodiment in that the retaining means 40 is positioned in the housing 60 before the magnet block 20 is mounted.

[0100] Therefore, before step e1 of inserting the magnet block 20, the assembly method according to this second embodiment includes the preliminary step of placing the holding means 40 on the body 10.

[0101] When inserted between the arms of the body 10, the magnet block 20 is compressed against the hub 11 (and therefore the spring is compressed), which, like the first embodiment, allows the circular ring 30 to be mounted without force, thanks to the gap between the outer periphery of the magnet block 20 and the circular ring 30.

[0102] Step e3 of activating the holding means 40 therefore consists in relaxing the compression of the magnet block 20 so that the holding means 40 can expand.

[0103] Next, a method for removing the rotor 1 will be described, which method comprises the following main steps: e4—stopping the holding means 40 so as to separate the magnet block 20 from the circular ring 30; e5—removing the circular ring 30 from the periphery of the magnet block 20; e6—removing at least one of the magnet blocks 20 from between the arms 12.

[0104] When the rotor 1 is assembled according to the first embodiment, the stopping step e4 comprises the following sub-steps: gripping and compressing the clip with a tool to de-energize the magnet block 20; Removing the retaining means 40 from the housing 60 through the opening 61 .

[0105] The magnet block 20 can then be moved closer to the body 10, typically until the inner surface 22 is in contact with the hub 11, creating a gap between the outer periphery of the magnet block 20 and the circular ring 30. Thus, during step e5 of removing the circular ring 30, the circular ring can be removed without difficulty.

[0106] When the rotor 1 is assembled according to the second embodiment, the stopping step e4 involves compressing the magnet block 20, and therefore the holding means 40, relative to the body 10 towards the longitudinal axis A1 to create the aforementioned gap.

[0107] One, several or all of the magnet blocks 20 can then be removed during a removal step e6 below.

[0108] This removal method has many advantages, such as allowing the elements of the rotor 1 to be replaced or repaired, or to separate and sort the different elements for the purpose of recycling them.

[0109] The invention is in no way limited to the embodiments described and presented, but a person skilled in the art will know how to provide any variant according to the invention.

Claims

1. A rotor (1) for an axial flux electric machine, said rotor (1) having a disk shape centered on a longitudinal axis (A1), a body (10) including a hub (11) having a plurality of arms (12) extending therefrom; a plurality of magnet blocks (20), each of which is disposed between two adjacent arms (12); a removable circular ring (30) arranged on the periphery of the rotor (1), surrounding the magnet blocks (20) and only in contact with the magnet blocks (20); One of the inner surface (31) of the circular ring (30) and the outer surface (23) of each of the magnet blocks (20) has a first recess (50), and the other has a complementary shape; The rotor (1) comprises a plurality of holding means (40), each of which is disposed between the body (10) and a magnet block (20) to urge the magnet block (20) against the circular ring (30), and the circular ring (30) and the magnet block (20) are nested in the first recess (50).

2. A rotor (1) according to claim 1, wherein said retaining means (40) are removable.

3. 3. A rotor (1) according to claim 1 or 2, wherein each of the holding means (40) is arranged in a housing (60) provided in the body (10), the housing (60) comprising an opening (61) designed to introduce the holding means (40) into the housing (60), the opening (61) having a size smaller than the size of the holding means (40).

4. A rotor (1) according to any one of claims 1 to 3, wherein the retaining means (40) is a spring, a clip, or a conical or frustoconical fret pin gauge.

5. A rotor (1) according to any one of claims 1 to 4, wherein each of said retaining means (40) is enclosed between an inner surface (22) of a magnet block (20) and said body (10).

6. A rotor (1) according to any one of claims 1 to 5, wherein each of said retaining means (40) is eccentric with respect to the thickness of said body (10) about said longitudinal axis (A1).

7. 7. A rotor (1) according to any one of claims 1 to 6, wherein each of the arms (12) includes two second recesses or protrusions (14) facing each other and extending in the extension direction of the arms (12), each of the magnet blocks (20) has two side surfaces (21), and each of the two side surfaces (21) includes a third recess or protrusion (24) having a shape complementary to the shape of the second recess or protrusion (14) of the arm (12) with which the side surface (21) is in contact.

8. A rotor (1) according to claim 7, wherein each of said second recesses or protrusions (14) has a depth or height that increases with approach to said longitudinal axis (A1).

9. A rotor (1) according to any one of the preceding claims, wherein each of the magnet blocks (20) comprises a plurality of single magnets (25) glued or arranged on a peripheral support (26).

10. A rotor (1) according to any one of claims 1 to 9, wherein vibration isolation means are provided between each magnet block (20) and the hub (11).

11. A method for assembling a rotor (1) according to any one of claims 1 to 10, comprising the steps of: inserting the magnet block (20) between the arms (12); Mounting the circular ring (30) around the magnet block (20) so that the circular ring (30) is in contact only with the magnet block (20); and actuating the retaining means (40) between the body (10) and the magnet block (20) so as to urge the magnet block (20) against the circular ring (30).

12. A method for removing a rotor (1) according to any one of claims 1 to 10, comprising: stopping the holding means (40) to separate the magnet block (20) from the circular ring (30); removing the circular ring (30) from the periphery of the magnet block (20); and removing at least one of the magnet blocks (20) from between the arms (12).

Images