CN115210994A - Rotor of axial flux electric machine - Google Patents

Abstract

The invention relates to a rotor (100) for an axial flux electrical machine, comprising a disc-shaped body (110) the outer edge of which is formed by at least one slot (120) which is separated by at least two edges (121), and at least one permanent magnet (130) is located in said slot, and at least two edges (131) are directed towards at least two edges of the slot. According to the invention, one edge of the slot opening extends along a mean line (D1) and has a cross section with a shape which varies along the mean line in order to form at least one first relief groove (140), in which case one edge of the permanent magnet has at least one correspondingly shaped second relief groove (141) to match the shape of the at least one first relief groove.

Description

Rotor of axial flux electric machine

Technical Field

The present invention relates generally to axial flux machines.

It is particularly relevant for a rotor of an axial flux machine, comprising:

-a body in the form of a disk overall, the outer edge of which has at least one notch separated by at least two edges, and

-at least one permanent magnet is located in said slot and at least two edges are directed towards at least two edges of the slot, respectively.

The invention has particularly advantageous application in the electric machines of electric or hybrid vehicles.

Background

Axial flux machines are usually composed of two stators and a rotor, and use an air gap to separate these two types of elements. The rotor has a series of permanent magnets and the stator has a series of coils.

When the coils pick up current, the rotor, which is fixed to the output shaft of the motor, is subjected to a torque generated by the magnetic field (the magnetic flux of which is the axial flux of the axial flux motor).

At present, the demand for electric machines capable of providing high mechanical power, while reducing the weight and space requirements, is very high.

One sensible way to increase the mechanical power provided by the motor is to increase the rotational speed of the rotor. It is also possible to increase its torque, but this method has certain drawbacks, such as increasing the weight and/or size of the engine, or increasing the losses due to joule effect.

Therefore, in order to keep the volume of the motor small, a lightweight rotor capable of withstanding high-speed rotation is designed.

Such a rotor is described specifically in US 2011006631. The rotor is disk-shaped, and the outer edge of the rotor is provided with a notch.

The permanent magnets are shaped to match the shape of the notches and are inserted into the notches. In order to make the fixing of these permanent magnets in the notches more effective, the edges of the permanent magnets are notched so that they can be fitted on the ribs provided along the edges of the notches. Typically, a layer of adhesive is applied to the grooves to ensure securement.

The main disadvantage of such a rotor is that the permanent magnets may fall off the rotor body when the rotor is rotating at extremely high speeds. In fact, when the rotor rotates around its rotation axis, the permanent magnets are subjected to high radial stresses due to centrifugal forces.

Therefore, there is a need for a rotor that better withstands the forces it experiences while maximizing the magnetic flux in the air gap.

Disclosure of Invention

To overcome the drawbacks of the background art described above, the present invention proposes to strengthen the fixation of each permanent magnet in the rotor body.

More specifically, according to the invention it is proposed to use a rotor as defined in the preamble, wherein at least one edge of the slot extends along a mean line for a length and forms a cross-section with this mean line, the shape of the cross-section varying along the mean line in order to form at least a first relief groove and to retain therein at least a part of one edge of the permanent magnet, which edge faces the groove, and at least one correspondingly shaped second relief groove to match the shape of the at least one first relief groove.

Thus, with this invention, the surface area of the permanent magnet bonded to the body is increased.

Machining and assembly difficulties may prevent the release slots from being opened on the edges of the notches and the edges of the permanent magnets.

However, the greater adhesion surface between the permanent magnet and the body ensures a better fixation of the assembly, in particular a better resistance to centrifugal forces. Since the normal direction of the joint face has a further variable direction, the stress caused by the centrifugal force is divided into tensile stress and shear stress. This will improve the bonding efficiency. Thus, the possibility of the permanent magnet falling off from the main body is greatly reduced.

Furthermore, since the larger bonding area increases the resistance to centrifugal forces, any additional accessories for fixing the magnets, such as a support disk surrounding the rotor or a layer of adhesive around the rotor, can be miniaturized or even eliminated. This makes it possible, on the one hand, to reduce the weight of the rotor and, on the other hand, to reduce the distance of the air gap, in order to maximize the circulation of the magnetic flux.

Advantageously, a gap is provided between the at least one slot edge and the at least one permanent magnet edge, said gap extending at least over a part of the long side of the slot and only over a part of the body bead.

Thus, the effect of applying a layer of adhesive or varnish around the rotor is greatly improved. The gap increases the thickness of the adhesive or varnish layer between the edge of the slot and the edge of the permanent magnet. This layer is thicker and therefore more elastic than before, which makes it better able to absorb the slight movements of the permanent magnets opposite the body due to centrifugal forces.

Advantageously, the permanent magnet consists of a magnet and a housing at least partially surrounding the magnet, the magnet having at least one relief groove corresponding to the shape of the second relief groove. By having the magnet shape correspond to the shape of the slot edges, the magnet volume can be maximized relative to the total volume of the permanent magnets (and thus relative to the rotor volume), thereby improving the magnetic performance of the rotor.

Advantageously, the collar surrounds the outer edge of an assembly formed by the above-mentioned body and the at least one permanent magnet, the inner diameter portion of the collar being smaller than the outer diameter of said assembly in the disassembled state.

The use of a collar having a diameter smaller than the diameter of the assembly formed by the main body and the permanent magnet ensures that the permanent magnet remains well fixed in the slot, while facilitating its mounting over a larger diameter by its end. Since such a ferrule is already subjected to pressure, the magnetic holding force of the permanent magnet due to centrifugal force is reduced. Furthermore, this geometry of the ferrule makes it possible to improve the distribution of the adhesive between the ferrule and the body when the ferrule is mounted.

Other advantageous and non-limiting characteristics of the rotor according to the invention are now set out (alone or in all technically possible combinations) as follows:

-at least one edge of the slot opening has a plurality of first relief grooves and at least one edge of the permanent magnet has a plurality of correspondingly shaped second relief grooves to match the shape of the plurality of first relief grooves;

-at least one of said first relief grooves has a flat surface;

-at least one edge of the permanent magnet is in contact with at least one edge of the slot over its entire length;

-at least one of said first relief grooves having a normal to any point of said surface directed outwardly of the notch;

one edge of the slot has a rib or a groove extending at least over part of the length of the permanent magnet, which permanent magnet has a groove or a correspondingly shaped rib, respectively (preferably forming a seal); and

-said at least one notch extends over the entire thickness of said body.

Of course, the various features, variants and embodiments of the invention may be interrelated in different combinations, as long as they are not mutually incompatible or mutually exclusive.

Drawings

The following description, provided by way of non-limiting example, and with reference to the accompanying drawings, will clearly illustrate the construction and how this invention may be carried out.

In the attached drawings:

fig. 1 is a schematic view of a rotor of an electric machine.

Fig. 2 is a schematic exploded view of the rotor part of fig. 1, showing a state before permanent magnets are inserted into the slots.

Fig. 3 isbase:Sub>A sectional view taken alongbase:Sub>A-base:Sub>A of fig. 2.

Fig. 4 is a sectional view taken along B-B of fig. 2.

Fig. 5 is a cross-sectional view along the plane C-C of fig. 1.

Fig. 6 is a cross-sectional view taken along line D-D of fig. 1.

Figure 7 shows schematically figure 6 before assembly of the rotor.

Detailed Description

Fig. 1 shows a rotor 100 of an electric machine. The rotor 100 is composed of a main body 110, a plurality of permanent magnets 130, and a collar 150.

The body 110 is generally disc-shaped, i.e. it is substantially constrained by a cylinder of rotation about an axis, hereinafter referred to as the axis of rotation A1. Its height (the size of the body along the axis of rotation A1) is much smaller than its diameter. In the following description, this height is referred to as the thickness of the body 110. Thus, the body 110 has two planar circular faces, parallel to each other and perpendicular to the rotation axis A1 of the rotor 100, one of which is shown in fig. 1.

As shown in fig. 1, the body 110 has a central recess for receiving a drive shaft extending along the rotational axis A1. The rotor 100 is designed to be fixed to the drive shaft, which is used to drive the rotor.

For example, the body 110 may be made of aluminum, steel, iron, titanium, or an alloy containing these metals. It is made, for example, of a stack of metal plates having a thickness of less than or equal to 1 mm. These metal plates are here bent, radially stacked. They extend over the entire height of the body 101. Therefore, stator losses due to eddy currents are limited. The body 110 is preferably made of a glass or carbon fiber reinforced composite material.

As shown in fig. 2, the body is composed of three layers, two outer layers 112, 114 and a central layer 113, which are substantially identical in shape. The three layers are stacked along the rotation axis A1, forming the body 110. Alternatively, the body 110 may be machined from a single piece.

As shown in FIG. 1, the outer edge of the body 110 has a plurality of notches 120. Here, the body 110 has 12 identical notches 120. The notches 120 are regularly distributed over the entire outer edge of the body 110. This ensures that the rotor 110 is well balanced when rotating.

In other words, the body 110 includes a central hub and a plurality of branches extending outwardly from the hub in a generally radial direction relative to the axis of rotation A1. As shown in fig. 1, the branches are slightly reduced in the direction of the outer periphery of the rotor 100. The 12 branches in fig. 1 are identical and are regularly distributed on the hub so as to be separated in pairs by a space, and then a notch 120 is formed by each pair of adjacent branches. Here, the notches are radially outward, i.e. towards the outer edge of the rotor 100.

As shown in fig. 2, each notch 120 preferably extends through the entire thickness of the body 110. This has the advantage of providing two opposing working surfaces. Such a rotor 100 may be formed of two stators, for example, to provide more mechanical power.

Each notch 120 is generally U-shaped with a spacer arm, two substantially radially extending sides 121, and a bottom portion referred to herein as an inner edge 122.

Here, the inner edge 122 is straight (it is a plane). As a variation, the inner edge 122 may be curved, e.g., having the same radius of curvature as the body 110.

As another variation, the notch 120 may be V-shaped with only two sides, an inner edge 122 being absorbed onto a side 121 formed by the contact of the two sides.

In this example, each notch 120 has three straight sides, including two lateral sides 121, which move from the center 110 of the body to the outside of the body. This geometry allows for simple engagement movement in the radial direction A2 (relative to the rotational axis A1) to simply radially insert the permanent magnet 130 into the slot 120.

Advantageously, as shown in fig. 2, each side of the slot 120 is designed to provide a groove 160, which may extend longitudinally in a generally radial direction. Each groove 160 has a U-shaped cross-section and is located between two side walls 161. As shown in fig. 3 and 4, the side walls 161 separating the U-shape here are formed by the two outer layers 112, 114 of the body 110. Each groove 160 is located at an intermediate position between the two circular faces of the body 110.

Furthermore, the inner edge 122 may have a relief groove, for example, formed by the difference in the radial extension of the outer edges 112, 114 and the radial extension of the intermediate layer 113. Thus, the inner edge 122 may have a groove 160 similar to the side 121 of the notch 120. At this time, the permanent magnet 130 has a supplementary shape, and can be installed in the relief groove.

Each groove 160 is designed to cooperate with a corresponding rib 170 on the permanent magnet 130 and protrudes from a lateral edge thereof. Such slot and rib type assemblies ensure high resistance of the permanent magnets 130 when subjected to axial forces and attraction of the permanent magnets 130 to the stator coils when the rotor 100 is operated relative to the electric machine.

As a variant, it is possible to design each rib to project from a lateral edge of the slot, with each groove extending to one lateral edge of the permanent magnet 130.

Each side 121 of the slot 120 extends longitudinally along a mean line D1 (here, a direction orthogonal to the axis of rotation A1). The average line D1 here is a straight line. As a variant, the mean line may also be a curve.

Here, the average line D1 is defined as a line that is as close as possible to the geometric center of the curved surface formed by the lateral edge segments by averaging (this edge is considered to extend generally along a cross-section that is orthogonal in radius). Thus, the mean line can be defined as the linear regression line at the geometric center of the surface formed by the transverse edge segments.

Each permanent magnet 130 has a shape adapted to be inserted into the slot 120. As shown in fig. 1 and 2, each permanent magnet 130 is generally trapezoidal in shape. The thickness (dimension in the direction of the rotation axis A1) of each permanent magnet 130 is substantially equal to the thickness of the main body 110.

Thus, each permanent magnet 130 has two magnet edges 131 located opposite to the lateral edges 121 of the insertion slot 120. The geometry of magnet edge 131 is nearly identical to the geometry of side 121. The magnet rim 131 design is provided with ribs 170 to facilitate installation into the groove 160.

According to the invention, each recess 120 has at least one side 121 extending along a respective median line D1, which has a cross section whose shape varies along the median line so as to form at least one first relief groove 140, and a second relief groove 141 of corresponding shape matching the shape of the first relief groove 140 when at least part of the magnet edge 131 is in contact with the side 121.

Here, both sides of the notch 120 are the same.

FIG. 3 illustratesbase:Sub>A first section A-A of the lateral edge 121 of FIG. 2 showingbase:Sub>A first cross-section at the first relief groove 140. Fig. 4 shows a second section B-B of the transverse edge 121 of fig. 2, which section shows a second cross section in the section without the first relief groove 140.

As shown in fig. 3 and 4, the shape of the cross-section of the average line D1 varies between the two profilesbase:Sub>A-base:Sub>A and B-B along the average line D1. Here, since the first relief groove 140 is protruded from the lateral edge 121, the sidewall 161 of the dividing groove 160 is higher in the first cross section than in the second cross section. In other words, the grooves 160 in the first relief groove 140 are deeper than the grooves 160 in the area without the first relief groove 140.

Here, the shape of the cross section of the average line D1 is a U shape whose depth linearly varies along each section of the average line D1 between the minimum depth and the maximum depth.

The relief slots 140, 141 increase the contact surface between the permanent magnet 130 and the body 110, and more particularly, between the sides 121 of the slot 120 and the magnet edge 131.

Here, as shown in fig. 6, a layer of adhesive 190 is applied to the notches 120 between the permanent magnet 130 and the body 110 (on the body 110 and/or the permanent magnet 130). The function of this layer of adhesive 190 is to ensure that when the rotor 100 rotates, the permanent magnets 130 are fixed in the slots 120 and that the permanent magnets 130 are subjected to high centrifugal forces (the higher the rotation speed, the greater the centrifugal force).

Therefore, increasing the contact surface increases the adhesion surface, thereby ensuring better fixation of the permanent magnet 130 in the slot 120.

Furthermore, due to this invention, the direction of the contact surface (i.e. the bonding surface) is also different. In so doing, the stress experienced by the bond line may be better distributed between tensile and shear stresses as the rotor 100 rotates.

In the axial direction, here along the axis of rotation A1, the permanent magnet 130 is mainly fixed by the transverse slots 160. The body 110 is fabricated from a strong material, such as a glass or carbon fiber reinforced composite, that enables the permanent magnet 130 to be effectively axially fixed.

Advantageously, each side 121 has a plurality of first relief slots 140 and each magnet edge 131 has a corresponding plurality of second relief slots 141. Therefore, the adhesion surface is further increased, thereby enhancing the fixation of the permanent magnet 130 in the slot 120.

As shown in fig. 2, each side 121 has five first relief grooves 140 on both sidewalls 161 for dividing the groove 160. Here, the first relief groove 140 provides the end surface of the sidewall 161 of the groove 160 with a zigzag or zigzag shape composed of a broken line.

According to a corresponding relationship, each magnet edge 131 has ten second relief grooves 141: five on each side of the rib 170.

Here, the first relief groove 140 is a relief groove 161 protruding from an end surface of a side wall of the groove 160, and the second relief groove 141 is a notch in the magnet rim 131.

As a variant, the first relief groove 140 located on the side 121 of the notch 120 (more precisely on the side wall 161 of the notch 160) may be a notch, and the second relief groove 141 may protrude from the edge of the magnet 131. It is also possible to design the first relief groove 141 to include both a protruding groove and a notch, and the second relief groove 141 to include a corresponding notch and protruding groove.

It is also possible to locate the first relief groove design on the groove bottom and the second relief groove on the rib.

Preferably, each first relief notch 140 has a flat surface. This means that the corresponding second relief groove 141 also has a flat surface. In fig. 2, each first relief groove 140 has two rectangular end faces connected together by a stop face and two triangular lateral faces (here isosceles triangles).

The use of flat surfaces for relief grooves 140, 141 facilitates machining.

It is preferable that the magnet edge 131 is in contact with the side 121 of the slot 120 over the entire length thereof. In doing so, the contact surface between the permanent magnet 130 and the slot 120 is maximized.

The permanent magnet edge 131 is in contact with the side 121 of the slot 120 over its entire length, which means that the side 121 has a single contact surface adjacent to the associated magnet edge 131, which is a continuous surface extending from the inner edge 122 to the outer edge of the body 110. At this point, we can assume that the nesting is complete.

To enable assembly of the rotor, each first relief groove 140 is oriented in such a way that the permanent magnet 130 can engage in the notch 120 in the radial direction A2.

According to an advantage of the invention, the surface of each first notch 141 is always directed towards the outside of the notch 120 (towards its outer edge), instead of the inner edge 122. Therefore, the surface of each first relief groove 141 never faces the inner edge 122. The surface of each first relief groove 141 is orthogonal to the surface of the inner rim 122, subject to restriction.

As shown in fig. 1, a surface of each first relief groove 141 faces the outside of the notch 120. The notch is also understood to be, in the extreme case, in the direction perpendicular to the radial direction A2.

As shown in fig. 6, when the rotor 100 is assembled, there is a gap 143 between the main body 110 and the permanent magnet 130 at least partially along each lateral edge 121. This gap extends only a portion of the thickness of the body 110.

To form this gap 143, it may be designed, for example, that the height of the ribs 170 protruding from each magnet edge 131 is slightly greater than the depth of the corresponding groove 160. Thus, the first 140 and second 141 relief slots face each other over a short distance.

Typically, once the rotor 100 is assembled, it is painted with an external adhesive that covers the rotor 100. The outer adhesive layer may be applied by spraying in aerosol form or dipping the rotor 100 into a liquid adhesive.

In this step, the outer adhesive layer will penetrate into the gap 143. Gap 143 increases the thickness of the adhesive layer between lateral edge 121 and permanent magnet 130 (i.e., between lateral edge 121 and magnet edge 131). The glue layer is thicker than before and therefore more elastic. This allows better absorption of slight displacements of the permanent magnet 130 relative to the main body 110 when subjected to centrifugal forces. The adhesive may deform slightly but does not crack or break.

To further secure the permanent magnet 130 in the slot 120, a layer of adhesive may be applied between the inner edge 122 and the inner edge 132 of the permanent magnet 130.

All the advantageous features of the above described invention ensure a better fixation of the permanent magnet 130 in the body 110. The outer adhesive layer can be thinned. It is also possible to design without support disks (such disks are typically used to clamp the rotor for integration). This results in a lighter rotor 100 on the one hand and a reduced air gap distance (between rotor 100 and stator) on the other hand, thereby improving the performance of the machine.

As shown in fig. 1 and 2, each permanent magnet 130 has a flat inner edge 132 and an outer edge 180, except for two magnet edges 131.

The inner edge 132 abuts the inner edge 122 of the notch 120. The outer edge 180 is flush with the outer edge of the body 110. The outer edge 180 is curved with the same radius of curvature as the body 110. Therefore, the outer circumferential surface of the rotor 110 is cylindrical.

Each permanent magnet 130 has a housing 135 and a magnet 136.

The magnet 136 is part of the permanent magnet 130 and generates a static magnetic field. For example, it may be assembled from neodymium iron boron or barium cobalt.

Here, each of the magnets 136 is composed of a plurality of unit magnets, the length of which extends to the entire thickness of the permanent magnet 130, and the cross-section of which is hexagonal. The use of a plurality of unit magnets can reduce eddy current loss as compared to a single magnet of the same size. As a variant, the elementary magnets may have different cross-sections, for example square, triangular or circular.

The housing 135 surrounds the magnet 136, at the edge of the slot 120 and at the outer edge of the magnet 110. The housing 135 does not cover the main face of the magnet 136. The housing 135 is preferably made of a non-magnetic material. The housing 135 may be made of plastic or resin, such as epoxy.

As shown in fig. 1 and 2, the second relief notch 141 is comprised of a letter housing 135. However, the magnet 136 preferably has a relief groove (at the magnet edge 131) having a shape corresponding to the second relief groove 141. Here, the magnet 136 of each permanent magnet 130 has a saw-tooth profile, as does the side 121 of each slot 120. When the second relief groove 141 forms a notch in the housing 135, the magnet 136 also has a notch in the area of the second relief groove 141. The shape 141 of the second relief groove is followed as much as possible, thereby maximizing the volume of the magnet 136 relative to the volume of the permanent magnet 130. The adaptation of the magnet 136 to the second relief groove 141 may be achieved by arranging the unit magnets according to the shape of the notch 120.

As shown in fig. 1, the collar 150 of the rotor surrounds the outer edge of the body 110 and the outer edge 180 of the permanent magnet 130. The function of the collar 150 is to provide an additional fixing means for the permanent magnets 130 (to counter centrifugal forces) when the rotor 100 is rotating. The ferrule 150 is made of a composite material such as glass fiber, carbon fiber, or polymer fiber embedded in a resin.

Ferrule 150 is annular.

Advantageously, in the disassembled state, the inner diameter of the ferrule 150 is strictly smaller than the outer diameter of the body 110.

Ferrule 150 may undergo a slight elastic deformation when it is installed in place. Thus, the collar 150 is pre-stressed and provides more support for the permanent magnet 130.

The outer edge of each permanent magnet may be designed to extend along the cylindrical surface.

However, as shown in fig. 2 and 5, the outer edge 180 of each permanent magnet 130 has a different shape, here three faces. The first face 181 extends along a cylindrical surface around the axis of rotation A1, extending to an extension of the outer periphery of the body 110, while the second face 183 extends along a cylindrical surface around a larger diameter of rotation. The third face 182 may connect two other faces together, which extend along the conical surface of rotation of the axis of rotation A1.

The inner surface of the collar 150 conforms to the inner surface of the magnet outer rim 180. Thus, the inner surface of the ferrule 150 also has three faces.

As a variant, the outer edge of each permanent magnet can be designed as a conical surface with a single rotation around the axis of rotation. The inner surface of the ferrule is a corresponding conical surface. In this case, in axial section, the profile of the ferrule is not isosceles trapezoidal.

The face diameter of the collar 150 of larger diameter is equal to the outer diameter of the body 110 within the gap and also equal to the outer diameter of the first face 181 of the outer rim 180 of the permanent magnet 130. Thus, ferrule 150 can be placed in position on this side of body 110. Ferrule 150 deforms upon insertion because the other face of the inner surface of ferrule 150 has a diameter less than the outer diameter of body 110.

The ferrule 150 is also bonded to the body 110 and the permanent magnet 130. Since the inner diameter of ferrule 150 in the disassembled state is smaller than the outer diameter of body 110, a small amount of adhesive can be applied to spread ferrule 150 evenly when it is installed.

Fig. 6 shows section D-D of fig. 1, illustrating the rotor 100 after the permanent magnets 130 are inserted into the slots 120 and the collar 150 are installed in place. A first layer of adhesive 190 is distributed between the notches 120 and the permanent magnets 130. Here, a first layer of adhesive 190 is distributed in the gap 143 between the slot edge 121 and the body of permanent magnet 130. A second layer of adhesive 191 is distributed between the permanent magnet 130 and the collar 150.

Fig. 7 shows the rotor 100, again in section D-D of fig. 1, before the permanent magnets 130 are inserted into the slots 120 and before the collar 150 is put in place. A first layer of adhesive 190 is disposed in the groove 160. A second layer of adhesive 191 is distributed at a third face 182 of the outer edge 180 of the permanent magnet 130.

In this case, the rotor 110 is assembled by radially inserting the permanent magnets 130 into the slots 120. Ferrule 150 may be installed in place at the same time, or at a second time.

When put in place, ferrule 150 is translated in the direction of rotational axis A1. Where ferrule 150 may be mounted with second layer of adhesive 190 distributed along outer edge 180. The internal dimensions of the collar 150 mean that the permanent magnet 130 can also be restrained in a direction towards the slot 120 by mounting it, as shown in figure 7. This restriction may facilitate or facilitate insertion of the rib 170 into the groove 160. When the rib 170 is inserted into the groove 160, the first layer of adhesive 190 is distributed along the edges of the slot 121.

As a variation, it is contemplated that a first layer of adhesive may be placed on the rib and then a second layer of adhesive may be placed on the collar.

As described above, once the collar 150 is in place, a layer of paint or a layer of external adhesive may be applied to the rotor 100. This fills the gap between the gap 120 and the permanent magnet 130, and between the permanent magnet 130 and the ferrule 150, wherein the first layer of adhesive 190 and the second layer of adhesive 191 will not spread. In particular, this may allow the gap 143 to be filled with adhesive.

In this assembly method, the first and second relief grooves 140 and 141 are shaped and oriented such that the permanent magnet 130 is completely received in the slot 120. In another variation, the permanent magnet 130 may be inserted into the intermediate layer 113 of the body 110 first. After this first step, the ribs 170 adjacent to the permanent magnets 130 are in contact with the bottom of the grooves 160 in the slots 120. In a second step, the outer layers 112, 114 side of the body 110 are plated on the intermediate layer 113. Here, the first relief groove 140 is manufactured in these outer layers 112, 114 of the body 110 and inserted into the second relief groove 141 manufactured in the outer shell 135 of the permanent magnet 130.

In this variation of the assembly method, the shape and orientation of the first and second relief grooves 140, 141 are not limited by the radial insertion of the permanent magnet 130. Other alternative shapes for the first relief groove 141 are also contemplated, such as a shape that prevents the permanent magnet 130 from radially exiting when the rotor 100 is rotating.

Claims (10)

1. Rotor (100) of an axial-flux electrical machine, comprising:

-a body (110) of overall disc shape, the outer edge of which has at least one notch (120) separated by at least two borders (121), and

-at least one permanent magnet (130) located in said slot (120) and having at least two edges (131) facing at least two edges (121) of the slot (120), respectively,

at least one edge (121) of the notch (120) extends along a mean line (D1) and has a cross section with a shape that varies along the mean line (D1) so as to form at least one first relief groove (140),

the permanent magnet (130) has at least one edge (131) with a portion facing the recess (120), and at least one edge (121) with at least one second relief recess (141) of corresponding shape to match the shape of the at least one first relief groove (140),

in the notch (120), an outer edge of the main body (110) is recessed.

2. The rotor (100) of claim 1, wherein the edge (121) of at least one slot (120) has a plurality of first relief grooves (140), and wherein the edge (131) of at least one permanent magnet (130) has a plurality of correspondingly shaped second relief grooves (141) conforming to the shape of the plurality of first relief grooves (140).

3. The rotor (100) according to one of the claims 1 to 2, wherein at least one of the first slots (140) has a plane.

4. The rotor (100) according to one of claims 1 to 3, wherein at least one edge (131) of the permanent magnet (130) is in contact with at least one edge (121) of the slot (120) along its entire length.

5. The rotor (100) according to one of claims 1 to 4, wherein a normal of any point of the surface of at least one of the first slots (140) is directed towards the outside of the slot (120).

6. The rotor (100) according to one of claims 1 to 5, wherein the at least one permanent magnet (130) consists of a magnet (136) and a housing (135) at least partially surrounding the magnet (136), the magnet (136) having a relief groove corresponding to the shape of the at least one second relief groove (141).

7. The rotor (100) according to one of claims 1 to 6, wherein at least one edge (121) of the slot (120) has a groove (160) or a rib extending at least over part of its length and at least one permanent magnet (130) has a rib (170) or a correspondingly shaped groove.

8. Rotor (100) according to one of the claims 1 to 7, wherein there is a gap (143) between the edge (121) of at least one slot (120) and at least one edge (131) of a permanent magnet (130), the gap (143) extending at least over part of the length of one edge (121) of the slot (120) and only over part of the thickness of the housing (110).

9. The rotor (100) of one of claims 1 to 8, wherein the at least one notch (120) extends over the entire thickness (110) of the body.

10. The rotor (100) of one of claims 1 to 9, comprising a collar (150) surrounding an outer periphery of an assembly of said main body (110), and said at least one permanent magnet (130), wherein, in a disassembled state, an inner diameter portion of the collar (150) is smaller than an outer diameter of said assembly.

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