a part made of SMC (Soft Magnetic Composite) or ferrite material, installed around the teeth of an electrical machine.

Abstract

A magnetic flux-generating component comprising a magnetic circuit (1) in the form of a toothed ring (2), the ring (2) and the teeth (3) forming a single piece made from magnetic sheet metal, each tooth (3) having a constant cross-section from a base (9) to a free end (10), each tooth (3) receiving a support (15) wound with electrically conductive wire (16), the support (15) comprising a sleeve (17) surrounding the tooth (3) and extending from the base (9) to the free end (10) of the tooth (3), the support (15) comprising a free peripheral edge (18) attached to the sleeve (17) at the free end (10) of the tooth (3), the free peripheral edge (18) being flush with the free end (10) of the tooth (3) and extending opposite the wire (16), the support (15) being made of a ferromagnetic material. The peripheral edge (18) tapers from the sheath (17) to its contour (20).Figure for the abridged version: Fig. 1.

Description

Title of the invention: Part made of SMC (Soft Magnetic Composite) or ferrite material, installed around the teeth of an electrical machine. technical field

[0001] The invention relates to the field of rotating electrical machines equipped with a magnetic flux-generating component, the component comprising a magnetic circuit in the form of a toothed ring, the teeth each receiving a support wound with electrically conductive wire. The component is structured to generate, as required, an axial magnetic flux or a radial magnetic flux. The invention is used in vehicles such as electric or hybrid automobiles, buses, agricultural machinery, boats, aircraft, industrial machines, and other applications. Previous techniques

[0002] There are different kinds of rotating electrical machines equipped with a magnetic flux generating component. Generally, a machine comprises at least one stator and at least one rotor.

[0003] In the non-limiting case of operation by axial magnetic flux, a machine may comprise a rotor disposed between two stators, or a stator disposed between two rotors. Manufacturing the stator is a complex process that requires technical choices to be simplified. These choices include reducing manufacturing time and costs. There are various ways to make a stator.

[0004] An example consists of separately producing elements which will then be attached to a plate. An element is obtained by making a tooth from laminated iron, then partially covering the tooth with an electrically insulating layer such as a synthetic material, and then winding the insulating layer with a length of electrically conductive wire.

[0005] The plate fitted with the elements is a segmented stator, the advantage of which is the ease of winding the teeth. However, a difficulty arises during the assembly of the elements with the plate. The stator must be perfectly circular, with the teeth in contact with each other at their base, generally called the yoke. But the teeth are not perfect in the geometric sense of the term. In particular, the faces of each base are not perfectly flat; the faces exhibit a certain roughness, a consequence of the manufacturing processes. Once the teeth are positioned on the plate so that the bases are in contact to form a magnetic circuit, air gaps can appear in the form of spaces between the bases. This This creates defects in the flow of magnetic flux and reduces the overall performance of the machine, or can be a source of magnetically induced vibrations. In particular, a reduction in available torque and energy losses is observed.

[0006] To improve the flow of magnetic flux, a single-piece circuit structure has been proposed, obtained by winding a strip of magnetic iron. The strip, of constant width in its original state, is first unwound and guided flat in a cutting device, for example by stamping. The strip exits the device with notches, which define the gaps between the stator teeth, to be wound and form a toothed ring.

[0007] In the case of an axial magnetic flux stator, each tooth extends from its base to its free end in a direction parallel to the axial direction of the stator. It is possible to give the teeth different shapes, which affect the manufacturing of the stator as a whole as well as its operation.

[0008] In certain embodiments, each tooth has a variable cross-section, widening towards the free end. In practice, the tooth's cross-section is initially constant along almost its entire length, more precisely from its base to a limit slightly recessed from the free end. Between this limit and the free end, the tooth has two widenings, one facing one of the neighboring teeth, the other facing the other of the neighboring teeth. These widenings are generally called notch edges or isthmuses, a notch being a space between two teeth.

[0009] Slotted jaws offer several advantages. They reduce the mechanical torque fluctuations of the machine when running unloaded, without electrical current in the coils. The jaws also reduce eddy currents in the windings, which cause electrical losses. Furthermore, the jaws reduce no-load losses in the magnetic circuit or in the magnets when used with a magnetized rotor.

[0010] However, the notch jaws present some drawbacks. Indeed, the winding operation around each tooth must be carried out by passing the wires between the notch jaws. Consequently, the winding operation is tedious and often impossible to perform automatically. Furthermore, applying an insulating layer around the tooth is a delicate process.

[0011] In other embodiments, each tooth has a constant cross-section over its entire length, more precisely from its base to its free end.

[0012] One advantage of the tooth with a constant cross-section, i.e., without notch prongs, is that the winding operation can be carried out on a support made of insulating material away from the tooth. The material can be natural or synthetic, such as plastic or any equivalent. Once the winding is complete, the support, fitted with electrically conductive wire, is directly fitted onto the tooth. Winding the support is easy to perform, and its placement on a tooth can be achieved by a device of Automated assembly.

[0013] However, one of the disadvantages of the constant section tooth is that which results from the absence of notch prongs. The functions provided by the prongs, mentioned earlier, are lost.

[0014] Manufacturers have sought to simultaneously obtain the advantages of a tooth with a variable cross-section and the advantages of a tooth with a constant cross-section. To this end, a tooth with a constant cross-section has been proposed, equipped with notching jaws after the installation of a wound support.

[0015] In practical terms, tests were carried out to secure a thin, flat plate to the free end of each tooth of a stator, each plate extending beyond the end on two sides to form two notch prongs. It proved very difficult to manufacture laminated iron plates and to position them to form the prongs, the difficulty being largely due to the thinness of the plates.

[0016] An alternative to laminated iron has been proposed for the plate, in the form of a composite material: fine iron grains, in powder form, agglomerated in a polymer binder. The composite material is often referred to by the acronym SMC, which comes from the English expression Soft Magnetic Composite. This material can be molded and exhibits good magnetic properties, in particular permeability and high electrical resistivity.

[0017] Another alternative for the plate is to use a ferrite-type material: a binary magnetic ceramic. The ceramic is obtained from metal powders, primarily iron but also, as a complement, nickel, manganese, zinc, magnesium, copper, or other metals. The ceramic can also be molded.

[0018] Whether made of composite material or ferrite-type material, a plate is relatively easy to manufacture. However, the plate is a small, thin piece that must be handled and bonded to a tooth. At the stator scale, it is a series of plates that must be attached to the teeth. Attaching the plates is difficult, particularly because it requires considerable time and precision. Furthermore, complex and expensive tooling is needed for their installation.

[0019] In general, the manufacture of a flux-generating component, such as a stator or rotor, has the disadvantage of involving one or more difficult and / or complicated steps, at least for the production of the notch tips. Description of the invention

[0020] The invention aims to overcome the aforementioned drawbacks in the manufacture of a magnetic flux-generating component, such as a stator or rotor, in a rotating electrical machine. More specifically, the invention seeks to facilitate the realization The creation of notch beaks, or isthmuses, at the level of the teeth of a stator or rotor.

[0021] As a corollary, the invention aims to maintain the ease of setting up a wound support on a tooth.

[0022] The invention also aims to reduce manufacturing and maintenance costs, as well as machine downtime.

[0023] To this end, the invention proposes a magnetic flux generating component comprising a magnetic circuit in the form of a toothed ring, the ring and the teeth forming a single piece made from magnetic sheet metal, each tooth having a constant cross-section from a base to a free end, each tooth receiving a support wound with electrically conductive wire. The support comprises a sleeve that surrounds the tooth and extends from the base to the free end of the tooth, the support comprising a free peripheral edge attached to the sleeve at the free end of the tooth, the free peripheral edge being flush with the free end of the tooth and extending opposite the wire, the support being made of a ferromagnetic material.

[0024] By its shape and the material from which it is made, the peripheral edge delimits two notch edges. A portion of the edge facing one of the adjacent teeth forms a first edge, and another portion of the edge facing the other adjacent tooth forms a second edge. It follows that the support fulfills two functions. One of these is the simplification of the winding operation, which is carried out away from the tooth before the support is attached to it. The other function is the creation of the notch edges. Compared to the prior art, the invention has changed the way the edges are attached by securing them to the support rather than to the tooth.

[0025] With the invention the effects obtained and the advantages that result from it are multiple.

[0026] The invention increases the iron surface area available for the circulation of magnetic flux. This increase is provided by the ferromagnetic material of the support. This allows for an increase in the torque supplied by the component, and therefore by the machine.

[0027] Parts of a laminated iron stator can be brought very close to a rotor. These parts are the free ends of the teeth, which are not covered by plates. This allows for better conduction of the magnetic flux, and therefore better efficiency of the machine equipped with the component.

[0028] The notch jaws are easily installed without being fixed to a tooth, since they are integral with the winding support. The jaws can therefore be removed: simply detach the support. Consequently, maintenance is simplified, and operating costs are lower.

[0029] A support is obtained by a molding technique. Thus, each support has the same dimensions. This allows for easy and quick placement of the supports on the teeth, while simplifying the manufacturing process. An advantage which... The result is the geometric precision of the component: the position of the notch prongs is precise and regular at the periphery of the component.

[0030] Because it contains a large number of iron particles, the support conducts heat well. This advantageously results in improved heat transfer to a tooth from a winding, due to the Joule effect. Consequently, the cooling of the component is improved.

[0031] In one embodiment, the support comprises a basic peripheral edge attached to the sleeve at the base of the tooth, the basic peripheral edge extending opposite the wire. This causes the support to accommodate three winding faces. As a result, the wire is held more securely, and the support is easier to handle.

[0032] The sleeve, the free peripheral edge, and the peripheral support edge form a single piece. This piece, generally obtained by molding, for example by injection molding, has dimensions that are identical for all supports. As a result, the geometry of the component, which depends in part on the geometry of its constituent elements, is much more precise and consistent for mass production.

[0033] The ferromagnetic material is a composite material comprising iron grains in a synthetic matrix, or the ferromagnetic material is of the ferrite type. This makes the support magnetically conductive. As a result, the volume of material available for the flow of magnetic flux is greater. Consequently, the useful magnetic torque is greater.

[0034] A bonding agent is placed between the tooth and the support, and / or an insulating layer is placed between the wire and the support. The bonding agent facilitates the placement of the support on the tooth, as it is liquid or viscous in this phase and acts as a lubricant. The bonding agent then holds the support on the tooth because it has hardened. The insulating layer reinforces the insulation already present on the electrical wire.

[0035] The component is a stator. In this case, the component is a fixed part of a machine.

[0036] Each cross-section of a tooth is parallel to the crown. In this case, the wire of each winding is wound along an axis parallel to the axis of the crown. It follows that the magnetic flux of the stator is axial.

[0037] The component is a rotor. In this case the component is a moving part of the machine, more precisely a rotating part.

[0038] The invention also relates to a rotating electrical machine comprising a magnetic flux generating component, in particular a stator, comprising a toothed ring made from magnetic sheet as shown above.

[0039] The invention further relates to a method for manufacturing a magnetic flux generating component for a rotating machine, the method comprising a manufacturing step The method involves creating a magnetic circuit in the form of a toothed ring, the ring and teeth forming a single piece of magnetic sheet metal, each tooth of a selection having a constant cross-section from a base to a free end. The method includes a step of producing a wire-wound support of electrically conductive wire for each tooth of the selection, the support comprising at least a sleeve and a free peripheral edge attached to the sleeve, the support being made of a ferromagnetic material, the method including a step of positioning the wire-wound support so that the sleeve surrounds the tooth and so that the free peripheral edge is flush with the free end of the tooth. Brief description of the drawings

[0040] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example and made with reference to the accompanying drawings in which:

[0041] - [Fig. 1] is a perspective view of a magnetic circuit for a component magnetic flux generator, according to one embodiment of the invention,

[0042] - [Fig.2] is a perspective view of an electrically wound wire support conductor, in place on a tooth of the magnetic circuit of the [Fig.1],

[0043] - [Fig.3] is a section along III-III of [Fig.2],

[0044] - [Fig.4] is a diagram that describes the structure of a material used in the invention. Detailed description

[0045] Figure 1 shows, for the described embodiment, a magnetic circuit 1 intended for manufacturing a component of a rotating electrical machine. The component as a whole is not shown. Nor is the machine.

[0046] The magnetic circuit 1 has the general shape of a toothed ring, with axis L1, comprising the ring 2 itself and teeth 3. The ring 2 and the teeth 3 form a single piece made from magnetic sheet metal, in this case a strip of constant width. The strip is left intact on one side and notched on the other. The notches, obtained by any suitable means such as a stamping device, define slots 4 between two successive teeth 3. It is the winding of the notched strip that gives the magnetic circuit 1 its shape. In the described embodiment, the magnetic circuit 1 comprises twenty-four teeth, although this number may be smaller or larger.

[0047] By way of exception, the teeth 3 are evenly distributed around the periphery of the crown 2. The teeth 3 and the notches 4 all have the same dimensions. This allows the magnetic flux to flow regularly.

[0048] Each tooth 3 extends lengthwise between an external face 5 and an internal face 6. The The outer face 5 is located at an external diameter of the magnetic circuit 1, which is also the external diameter of the ring 2. Thus, the outer face 5 is convex, that is, curved and protruding. The inner face 6, on the other hand, is located at an internal diameter of the magnetic circuit 1, which is also the internal diameter of the ring 2. Thus, the inner face 6 is concave, that is, curved and concave.

[0049] Each tooth 3 extends in width between a first lateral face 7 and a second lateral face 8. The first lateral face 7 partially delimits a notch 4 and the second lateral face 8 partially delimits another notch 4. Each of the first and second lateral faces 7, 8 is flat and perpendicular to the crown 2.

[0050] Each tooth 3 extends vertically from a base 9 to a free end 10, the base 9 being the part of the tooth 3 which is at the level of the crown 2. The bases 9 of each tooth 3 are respectively located in the same plane perpendicular to the axis L1 of the circuit 1. As a corollary, the free ends 10 of each tooth 3, which are planar, are respectively located in another plane also perpendicular to the axis L1 of the circuit 1.

[0051] It follows from the above that each cross-section of a tooth 3 is constant from its base 9 to its free end 10. Each cross-section is parallel to the ring 2. In other words, a plane which contains a cross-section of the tooth 3 is perpendicular to the axis L1 of the magnetic circuit 1. It can also be said that the tooth 3 protrudes in the axial direction L1 of the ring.

[0052] Figures 2 and 3 show how a tooth 3 accommodates a support 15 wound with electrically conductive wire 16.

[0053] According to the invention, the support 15 includes a sleeve 17 which surrounds the tooth 3 and extends from the base 9 to the free end 10 of the tooth 3. The support 15 also includes a free peripheral edge 18 attached to the sleeve 17 at the free end 10 of the tooth 3. The peripheral edge 18 is perpendicular to the sleeve 17. The peripheral edge 18 is flush with the free end 10 of the tooth 3, in the sense that it borders the end 10 without covering it, and extends opposite the wire 16, for example along the entire thickness of the winding. The peripheral edge 18 tapers from the sleeve 17 to its contour 20. Thus, the peripheral edge 18 defines a notch beak projecting from the first lateral face 7 of the tooth 3, and a notch beak projecting from the second lateral face 8 of the tooth 3, the beaks being carried by the sleeve 17.

[0054] By way of exception, the support 15 further comprises a basic peripheral edge 19 attached to the sleeve 17 at the base 9 of the tooth 3. The basic peripheral edge 19 is perpendicular to the sleeve 17 and extends along the electrical wire 16, again, for example, through the entire thickness of the winding. The basic peripheral edge 19 has a constant thickness from the sleeve 17 to its contour 21.

[0055] The support 15 is made of a ferromagnetic material. Consequently, the sleeve 17, the free peripheral edge 18, and the base peripheral edge 19 are respectively made of a ferromagnetic material. Without limitation, as shown in [Fig. 4], the ferromagnetic material is a composite material comprising iron grains 22 in a synthetic material matrix 23. The iron grains 22 are generally nanoparticles or microparticles. Dimensions between 5 and 500 nm have given good results. The synthetic material 23 is a thermoformable material, such as polyamide, polyethylene, polyvinyl chloride, or any equivalent.

[0056] By way of exception, the sleeve 17, the free peripheral edge 18, and the base peripheral edge 19 form a single piece. This can be obtained by any suitable technique such as injection molding. A single-piece molded part is easy to produce and offers high dimensional accuracy. Consequently, the dimensional accuracy of the magnetic circuit 1 is also high. This advantageously results in a homogeneous flow of the magnetic flux.

[0057] With further reference to [Fig. 3], it can be seen that a bonding agent 24 is disposed between the tooth 3 and the support 15. In practice, this agent 24 is an adhesive, a resin, or any suitable material. Without limitation, the bonding agent extends along the sleeve 17 and along the peripheral base edge 19. This distribution provides the largest possible bonding surface, for better adhesion of the support 15 to the tooth 3.

[0058] An insulating layer 25 can also be seen arranged between the wire 16 and the support 15. The insulating layer 25 reinforces the electrical insulation between the winding and the support 15.

[0059] When in place on the tooth 3, the wound support 15 increases the amount of material capable of carrying a magnetic flux. Indeed, both the tooth 3 and the sleeve 17 conduct magnetic flux, and not the tooth alone. This results in improved energy efficiency of the magnetic circuit 1, and consequently improved efficiency of the machine in which it is installed.

[0060] The invention is not limited to the embodiment described, and includes all equivalents that may fall within the scope of the following claims.

[0061] In particular, various shape variants can be provided for the components of the magnetic circuit 1. For example, each tooth could be oriented in a radial direction of the ring 2. In this case, a cross-section of the tooth would be parallel to the axis L1 of the magnetic circuit 1.

Claims

Demands

1. A magnetic flux-generating component comprising a magnetic circuit (1) in the form of a toothed ring (2), the ring (2) and the teeth (3) forming a single piece made from magnetic sheet metal, each tooth (3) having a constant cross-section from a base (9) to a free end (10), each tooth (3) receiving a support (15) wound with electrically conductive wire (16), the support (15) comprising a sleeve (17) surrounding the tooth (3) and extending from the base (9) to the free end of the tooth (3), the support (15) comprising a free peripheral edge (18) attached to the sleeve (17) at the free end (10) of the tooth (3), the free peripheral edge (18) being flush with the free end (10) of the tooth (3) and extending opposite the wire (16), the support (15) being made of a ferromagnetic material,characterized by the fact that the peripheral edge (18) tapers from the sheath (17) to its contour (20).

2. Component according to claim 1, wherein the support (15) comprises a basic peripheral edge (19) attached to the sleeve (17) at the level of the base (9) of the tooth (3), the basic peripheral edge (19) extending opposite the wire (16).

3. Component according to claim 2, wherein the sleeve (17), the free peripheral edge (18) and the base peripheral edge (19) form a single piece.

4. Component according to any one of claims 1 to 3, wherein the ferromagnetic material is a composite material comprising iron grains (22) in a synthetic material matrix (23), or wherein the ferromagnetic material is of the ferrite type.

5. Component according to any one of claims 1 to 4, wherein a bonding agent (24) is disposed between the tooth (3) and the support (15), and / or an insulating layer (25) is disposed between the wire (16) and the support (15).

6.

7. A component according to any one of claims 1 to 5, which is a stator. A component according to claim 6, in which each cross-section of a tooth (3) is parallel to the crown (2).

8.

9. A component according to any one of claims 1 to 5, which is a rotor. A rotating electrical machine comprising a magnetic flux generating component according to any one of claims 1 to 8.

10. Method for manufacturing a magnetic flux-generating component for a rotating machine, the method comprises a step of producing a magnetic circuit (1) in the form of a toothed ring (2), the ring (2) and the teeth (3) forming a single piece of magnetic sheet, each tooth (3) having a constant cross-section from a base (9) to a free end (10), the method being characterized in that it comprises a step of producing a support (15) wound with electrically conductive wire (16) for each tooth (3), the support (15) comprising at least one sleeve (17) and a free peripheral edge (18) attached to the sleeve (17), the peripheral edge (18) tapering from the sleeve (17) to its contour (20), the support (15) being made of a ferromagnetic material, the method comprising a step of positioning the wound support (15) so that the sleeve (17) surrounds the tooth (3) and so that the free peripheral edge (18) is flush with the free end (10) of the tooth (3).

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