Stator assembly, corresponding electric motor, and associated motor-fan unit, particularly for motor vehicles

Abstract

The invention relates to a stator assembly for an electric motor of a fan assembly comprising a fan wheel, the electric motor being configured to drive the fan wheel in rotation. The stator assembly comprises a winding support (12) centered around an axis and comprising a plurality of arms (121) extending radially with respect to the axis of the winding support (12). The arms (121) delimit, in pairs, a respective slot (122), and a winding comprising a plurality of windings, one winding being formed around each arm (121). According to the invention, the stator assembly is characterized in that the slots (122) have a respective slot bottom (123) generally rounded inwards towards the winding support (12).The invention also relates to an electric motor and a corresponding motor-fan assembly. Figure for the abstract: Fig. 4.

Description

Title of the invention: Stator assembly, corresponding electric motor, and associated motor-fan unit, particularly for motor vehicles technical field

[0001] The invention relates to a stator assembly for an electric motor. The invention also relates to an electric motor comprising such a stator assembly, as well as to a motor-fan unit or ventilation device comprising such an electric motor, which may be intended for use in vehicles, particularly automobiles. The invention may be applied, for example, to heating, ventilation, and / or air conditioning systems for vehicles, particularly automobiles, comprising such a motor-fan unit. Technical background

[0002] Vehicles, particularly automobiles, are commonly equipped with a system, for example, a heating, ventilation, and / or air conditioning system, which circulates air, particularly within the vehicle's passenger compartment. Such a system also manages the temperature and distribution of the airflow within the passenger compartment. This system includes, among other things, a fan, particularly a blower fan, comprising a fan wheel driven by a drive motor, particularly an electric one. The electric motor may, in particular, be electronically commutated and controlled by a control module.

[0003] An electronically commutated electric motor, or brushless DC motor (also known by the English name "brushless"), comprises a rotor and a stator assembly, carrying electromagnetic elements whose interaction generates the displacement of the rotor relative to the stator assembly, and thus the displacement of the fan wheel.

[0004] The electric motor is assembled in the installation, for example, of heating, ventilation and / or air conditioning by means of a motor support.

[0005] The stator assembly generally comprises a winding having a plurality of windings and a winding support. The winding support comprises a lamination centered around an axis and includes a plurality of arms extending radially from the axis of the winding support. A winding is wound around each arm of the winding support. The arms define a passage cross-section for a magnetic flux. When electric currents flow through the windings, magnetic fields are produced. The rotor is provided with a plurality of permanent magnets. also producing magnetic fields. The interaction of the magnetic fields produced generates the displacement of the rotor relative to the stator assembly, and consequently the rotation of the fan wheel.

[0006] A constant objective in the automotive industry, in particular, is to reduce weight. Specifically, one aim of the present invention is to provide a stator assembly whose weight is reduced without impacting the cross-sectional area useful for magnetic flux. Another objective of the invention is to optimize the shape of the winding support. Summary of the invention

[0007] To this end, the invention relates to a stator assembly for an electric motor of a fan unit comprising a fan wheel, the electric motor being configured to drive the fan wheel in rotation. The stator assembly comprises a winding support centered around an axis and comprising a plurality of arms extending radially with respect to the axis of the winding support, the arms delimiting, in pairs, a respective slot, and a winding comprising a plurality of windings, a winding being formed around each arm. According to the invention, the slots have a respective slot bottom that is generally rounded inwards towards the winding support.

[0008] In the present, "inwards" of an element means an orientation towards the center or substantially towards the center, that is to say, approaching the center of that element, for example of the winding support.

[0009] Thus, at the slot bottoms, the shape changes from convex to inwardly rounded, thereby reducing the radial thickness of the winding support without affecting the magnetic flux passing through it. This inwardly rounded shape of the slot bottoms allows for material removal to reduce overall weight wherever the magnetic flux passage cross-section is unnecessary. Furthermore, this optimized shape offers similar rigidity to previous solutions with a convex shape and greater radial thickness at the slot bottoms.

[0010] The stator assembly may further comprise one or more of the following characteristics described below, taken separately or in combination.

[0011] The slot bottoms are, in particular, generally concave in shape. Their concavity is oriented inwards (in other words, towards the center or substantially towards the center, i.e., approaching the center) of the winding support. Thus, at the slot bottoms, the shape changes from a convex shape, as in the previous solutions, to a concave shape.

[0012] The winding support may include a bridge or a link between each pair of adjacent branches.

[0013] The branches may be identical.

[0014] The winding support has at the level of the bridges or connections a section, with a minimum section which may be greater than or equal to 40%, preferably 50%, of a minimum section of a branch.

[0015] In particular, the minimum section may be greater than or equal to half of a section of a branch.

[0016] Each branch can have an elongated shape with a given width. The winding support, for example, has a constant height. In this example, the minimum width at the bridges or connections is therefore at least equal to 40%, or in particular half (50%), of the width of a branch.

[0017] The notches delimited between two arms of the winding support are, for example, axially through.

[0018] The winding support comprises, for example, a ring from which the arms extend radially. According to this example, the ring has a central opening and defines a theoretical inner circle and a theoretical outer circle such that the slot bottoms lie within the theoretical outer circle. The theoretical inner circle has a smaller diameter than the theoretical outer circle.

[0019] The ring may have, at the level of the theoretical inner circle, surfaces rounded inwards (in other words towards the center or substantially towards the center, that is to say approaching the center) of the ring, the rounded surfaces being opposite the bottoms of the notch.

[0020] The rounded surfaces at the level of the theoretical inner circle are, for example, concave.

[0021] The ring is, according to a particular embodiment, rounded inwards, in particular concave, on both inner and outer sides of the ring.

[0022] The winding support may include at the free end of a branch at least one tooth or foot. Each branch may be provided with at least one such tooth.

[0023] A tooth or a foot extends for example on either side of a corresponding branch, following the circumference of the winding support.

[0024] The teeth or feet at the free ends of the winding support arms may be designed to be arranged opposite rotor magnets. The rotor may have a cup shape, and the magnets may, for example, be fixed to an inner face of the cup shape.

[0025] The winding support comprises, for example, a bundle of sheets superimposed axially on each other.

[0026] The winding support may include at least one assembly member configured to cooperate with at least one fastening element, the assembly member being selected from a closed eyelet, an open eyelet, a recess, or a clamp shape. Assembly components in cooperation with the fastening elements allow the winding support, in particular the lamination pack, to be fixed to the motor support.

[0027] The winding support may include at least one positioning element configured to cooperate with a complementary element on a motor support on which the stator assembly is intended to be mounted.

[0028] The positioning element can be chosen from a rib, a tooth, a recess, a notch, an eyelet, an ear, a flat, a plate, an outgrowth, a protuberance.

[0029] The positioning element can have a centering function of the winding support, the sheet metal pack, on the motor support, for example a motor support tower.

[0030] Alternatively or in addition, the positioning element may have an anti-rotation function to prevent the stator assembly from being mounted in an incorrect position.

[0031] The invention also relates to an electric motor, in particular for a motor-fan unit, said motor comprising a rotor and a stator assembly as defined above.

[0032] This refers in particular to a brushless motor.

[0033] The invention further relates to a motor-fan unit, in particular of a motor vehicle, the motor-fan unit comprising a fan wheel, an electric motor, as defined above, configured to drive the fan wheel in rotation, and a motor support, the stator assembly being mounted on the motor support.

[0034] In the motor-fan group or ventilation device, the fan is in particular of the blower type.

[0035] The motor-fan unit can be intended for a heating, ventilation and / or air conditioning installation of a vehicle, in particular a motor vehicle. Brief description of the drawings

[0036] Other advantages and features of the invention will become more apparent upon reading the following description, given by way of illustrative and non-limiting example, and the accompanying drawings, among which:

[0037] [Fig. 1] is a perspective view of an embodiment of a motor-fan unit.

[0038] [Fig.2] is a cross-sectional view of the motor-fan assembly of [Fig.1].

[0039] [Fig.3] is a perspective view of an electric motor of the motor-fan assembly of the [Fig.l].

[0040] [Fig.4] is a perspective view of a winding support for the electric motor of [Fig.3] according to one embodiment.

[0041] [Fig.5] is a perspective view of a winding support for the electric motor of [Fig.3] according to another embodiment.

[0042] [Fig.6] is a perspective view of a winding support for the electric motor of [Fig.3] according to yet another embodiment.

[0043] In these figures, identical elements bear the same reference numbers.

[0044] The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments can also be combined or interchanged to provide other embodiments, without departing from the scope of the invention as defined by the claims. Detailed description

[0045] Figures 1 and 2 illustrate a motor-fan assembly 1, particularly for a vehicle such as a motor vehicle. This may specifically be a motor-fan assembly 1 for a heating, ventilation and / or air conditioning system, particularly for a vehicle.

[0046] The motor-fan assembly 1 (or ventilation device) includes in particular a fan wheel 3, a fan wheel drive motor 5, and a motor support 7 for the motor 5, hereafter referred to as the motor support 7.

[0047] The fan wheel 3, particularly of the blower type, rotates about an axis A of rotation. The motor 5 is intended to drive the fan wheel 3 in rotation about its axis A. In this document, the terms "axial", "coaxial", "axially", "radial" or "radially" are defined with respect to this axis A. The motor 5 is described in more detail below.

[0048] The motor support 7 is intended to allow the fixing of the motor-fan assembly 1 in the vehicle, in particular a motor vehicle.

[0049] The motor support 7 may include a base 71 for attaching the motor 5. The base 71 may be intended to be attached to the motor 5. The base 71 has an opening 72 through which a rotor shaft passes at least partially.

[0050] The base 71 can also be intended to be fixed, directly or indirectly, to a structural element of the vehicle, for example, a vehicle heating, ventilation and / or air conditioning system. In the illustrated example, the engine mount 7 has a mounting interface 73 to which the base 71 is fixed. This mounting interface 73 can advantageously also have a deflector function. air allowing, in operation of the motor-fan group 1, to divert at least part of the air set in motion by the fan wheel 3 towards a control module 11 of the motor 5 and / or towards the motor 5. The mounting interface 73 may be intended to be fixed to the vehicle.

[0051] The base 71 may have at least a partial shape of revolution about an axis coinciding, for example, with the axis A of rotation of the fan wheel 3 in the assembled state of the motor-fan unit 1. The base 71 may be centered about this axis A. The axis A hereafter refers to both the axis of the base 71 and the axis of rotation of the fan wheel 3. The base 71 may extend mainly along a plane normal to the axis A. For example, the base 71 may have an annular shape, or a ring shape, or a disc shape.

[0052] The motor support 7 advantageously carries the control module 11 of the motor 5. In particular, the base 71 can carry the control module 11. The control module 11 can include an electronic board (not visible in the figures) and at least one connector electrically connected to the electronic board for supplying power to the electronic board and, consequently, to the motor, when connected to an electrical harness, in particular of the vehicle.

[0053] In addition, the motor support 7 may include a bearing carrier 13 comprising a tower or chimney extending axially. The tower may be tubular in shape around the axis A.

[0054] Engine

[0055] As regards the motor 5, more clearly visible in figures 2 and 3, it is an electric motor 5, in particular a brushless motor 5 (also known by the English name "brushless").

[0056] The motor 5 comprises a rotor 5A and a stator assembly 5B, the rotor 5A being movable relative to the stator assembly 5B and capable of driving the fan wheel 3. The rotor 5A is, for example, an external rotor. The rotor 5A may have a cup shape fixed to a rotor shaft 51. Bearings 9 are mounted around the rotor shaft 51. The fan wheel 3 may be fixed directly to the rotor shaft 51. The rotor 5A may include magnets, for example, fixed to an inner face of the cup. The stator assembly 5B may be internal, that is, located inside the rotor 5A.

[0057] The stator assembly 5B can be fixed to the motor support 7.

[0058] The stator assembly 5B includes a winding support 12 fitted around an axis and an associated winding 14. The axis, i.e. the central axis of the winding support 12, can coincide with the axis A of rotation of the fan wheel 3 or the axis of the base 71. In the following description, axis A also designates the axis of the winding support.

[0059] The winding support 12 can be mounted around the tower of the bearing carrier 13.

[0060] The winding support 12 comprises at least one sheet metal 16, and preferably can comprising a stack of 16 plates axially superimposed on one another. The plates 16 may be identical to each other. According to one embodiment, each of the plates 16 fits within a disc, each of the plates 16 having a central hole, so that the stack of plates 16 is axially perforated to receive by insertion a cylindrical part, such as the bearing support tower 13.

[0061] With reference to Figures 3 and 4, the winding support 12 comprises a plurality of branches 121 extending radially with respect to the axis A of the winding support 12. Thus, each of the sheets 16 can have a shape with a plurality of radial branches 121.

[0062] Each arm 121 can carry an associated winding 141. More precisely, a winding 141 is formed around a superposition of corresponding arms 121 of each sheet 16. These are the arms 121 that are aligned with each other along the axis A. The rotor magnets 5A can be arranged radially outside with respect to the windings 141. The term radially is understood with respect to the axis A.

[0063] The branches 121 can be identical.

[0064] The branches 121 may have the same dimensions. In particular, the branches 121 may have a cross-section whose minimum cross-section is the same for several or even all of the branches 121.

[0065] Each branch 121 has an elongated shape of width LL. The branches 121 may have a minimum width L1 which may be the same for several or even all of the branches 121.

[0066] The winding support 12 can be provided with teeth or feet on the side of the free ends of the arms 121. Each tooth or foot extends for example on either side of a corresponding arm 121, according to the circumference of the winding support 12.

[0067] The teeth or feet at the free ends of the arms 121 of the winding support 12 are arranged opposite the magnets of the rotor 5A or a support surface for the magnets of the rotor 5A, for example an inner face of the cup shape of the rotor 5A.

[0068] The arms 121 delimit, in pairs, a respective notch 122. Thus, along the circumference of the winding support 12, the latter presents an alternation of arms 121 and notches 122. The notches 122 can be distributed angularly in a regular manner around the axis A.

[0069] The notches 122 delimited between two branches 121 of the winding support 12 are axially through.

[0070] The arms 121 are preferably parallel-edged, so that the inner faces opposite each other of the notches 122 are inclined relative to each other.

[0071] In addition, each notch 122 has a notch bottom 123 with a generally rounded shape towards the inside of the winding support 12. In particular, the notch bottoms 123 are generally concave in shape, with the concavity oriented towards the inside of the winding support 12.

[0072] “Inwards” corresponds to an orientation towards the center or substantially from the center, that is to say approaching the center, of the winding support 12.

[0073] This inwardly rounded, in particular concave, shape of the notch bottoms 123 makes it possible to remove material to reduce the overall weight, wherever the magnetic flux passage cross-section is superfluous.

[0074] Two adjacent branches 121 are connected by a bridge or link 124. Such a bridge or link 124 is therefore opposite a corresponding notch bottom 123.

[0075] The winding support 12 may have at the level of the bridges or links 124 a cross-section whose minimum (minimum cross-section) is greater than or equal to 40%, preferably half (50%), of the minimum cross-section of a branch 121. For reasons of clarity, the cross-section of a branch 121 is called the first cross-section and the cross-section at the level of the bridges or links 124 is called the second cross-section.

[0076] Such a ratio between the first minimum section of the branches 121 and the second minimum section of the links 124 with regard to the slot bottoms 123 makes it possible not to disturb the magnetic flux of the stator assembly while ensuring good mechanical strength of the latter.

[0077] The winding support 12, for example, has a constant height. The height extends axially.

[0078] The bridges or links 124 may in particular have a radial thickness L2 (or width) with respect to the axis A, the minimum of which is at least equal to 40%, preferably at least half (i.e. at least 50%), of the minimum width L1 of a branch 121.

[0079] The arms 121 can extend radially from a ring 125 of the winding support 12, more precisely from each sheet 16. Preferably, this is a central ring 125 with axis A as its axis. The arms 121 can be regularly distributed angularly around this ring 125. This gives, in particular, a general star shape to the winding support 12, to each sheet 16.

[0080] The teeth or feet at the free ends of the branches 121 are therefore opposite the ring 125.

[0081] The ring 125 has a central orifice. The central orifice can be configured to be traversed by the corresponding rotor shaft 51.

[0082] The ring 125 defines a theoretical inner circle Ci and a theoretical outer circle Ce. The theoretical inner circle Ci is schematically drawn by lines discontinuous on figures 4 and 5, and the outer circle. This theoretical is drawn schematically by dotted lines.

[0083] The theoretical inner circle Ci has a smaller diameter than the theoretical outer circle Ce.

[0084] The theoretical inner circle Ci is, for example, the smallest circle circumscribed by the surfaces of the ring 125 opposite the notch bottoms 123.

[0085] In other words, it is the inner circle defined without taking into account any possible elements opposite the branches 121, protruding towards the inside of the ring 125 or on the contrary cutting into the radial thickness of the ring 125, such as one or more assembly members 20 protruding towards the inside of the ring 125 and / or one or more recesses 22 cut into the ring 125 opposite the branches 121.

[0086] The notch bottoms 123 fit within the theoretical outer circle Ce of the ring 125.

[0087] The ring 125 may have, between the theoretical inner circle Ci and the theoretical outer circle Ce, a section whose minimum corresponds to the second minimum section which is greater than or equal to 40%, preferably half (50%) of the first minimum section of a branch 121. In particular, the ring 125 has between the theoretical inner circle Ci and the theoretical outer circle Ce, the radial thickness L2 with respect to the axis A.

[0088] The ring 125 may, in particular, have surfaces rounded towards the inside of the ring 125 at the level of the theoretical inner circle Ci (in other words, towards the center or substantially the center, i.e., approaching the center of the ring 125). The rounded surfaces are opposite the notch bottoms 123. The rounded surfaces at the level of the theoretical inner circle Ci are, for example, concave.

[0089] The ring 125 is, according to the particular embodiment shown, rounded inwards, in particular concave, on both inner and outer sides of the ring 125.

[0090] According to one variant, on the inner side of the ring 125, the shape could remain substantially circular.

[0091] The winding support 12 may include at least one insulator 18 arranged at least partially on one face of the stack of sheets 16, in particular a face normal to the axis A of the winding support 12. The insulator 18 covers at least partially the branches 121 of the winding support 12. For this purpose, it may have a shape complementary to the shape of a sheet 16.

[0092] According to one example, two insulators 18 can be arranged above and below the stack of sheets 16, that is, on either side of the stack of sheets 16 along axis A, as illustrated in [Fig. 2], in particular at opposite faces along axis A of the stack of sheets 16, so as to protect and insulate the windings of the stack of sheets 16. The insulators 18 are made of plastic parts. A insulator 18 can be on the side of the motor support 7 and another insulator 18 can be on the side of the fan wheel 3 in the assembled state of the motor-fan group 1.

[0093] At least one insulator 18, in particular the one on the side of the motor support 7, can be made from a part separate from the motor support 7.

[0094] In this particular case, the winding support 12, in particular the lamination pack 16, can be fixed to the motor support 7.

[0095] For this purpose, the winding support 12, in particular the sheets 16, include at least one assembly member 20, 20' (an example of which is shown in [Fig.5] or [Fig.6]) intended to cooperate with at least one fastening element, such as a screw for example.

[0096] The assembly member 20, 20' extends inward from the ring 125, and thus inward from the winding support 12. More precisely, the assembly member 20 extends radially from the theoretical inner circle Ci inward from the ring 125. The assembly member 20, 20' is advantageously positioned opposite a branch 121. This assembly member 20, 20' can be selected from a closed eyelet 20' ([Fig. 6]), an open eyelet 20 ([Fig. 5]), a recess, a clamp shape, or any other suitable shape. For example, at least three assembly members 20, 20' such as closed or open eyelets 20' can be provided. They are advantageously spaced 120° apart.

[0097] The assembly members 20, 20' for fixing, for example, by screws, may also offer an anti-rotation function. In the case of three assembly members 20, 20' such as three eyelets 20, 20', only three angular positions are acceptable for mounting the winding support 12 on the motor support 7.

[0098] According to one embodiment, the insulator 18 on the side of the motor support 7 can be integrated into the motor support 7, i.e., formed as a single piece with it. According to this embodiment, fasteners such as screws are not required; the windings allow the insulator on the opposite side, as well as the insulator integrated into the motor support, to be held in place on the lamination pack 16.

[0099] As an alternative or in addition to the assembly member 20, 20', the winding support 12 may include at least one positioning element configured to cooperate with a complementary element on the motor support 7, so as to participate in the correct positioning of the winding support 12. The positioning element may be chosen from a rib, a tooth, a recess, a notch, an eyelet, an ear, a flat, a plate, an outgrowth or a protuberance.

[0100] Furthermore, at least one positioning element may have a centering function of the winding support 12, of the sheet metal pack 16, on the motor support 7, for example around the tower of the motor support 7.

[0101] Alternatively or in addition, at least one positioning element may have an anti-rotation function to prevent the stator assembly from being mounted in a position that is not correct.

[0102] According to a particular example, the additional positioning elements carried on the one hand by the winding support 12 and on the other hand by the motor support tower 7 can be formed by ribs, for example axial ribs, and notches or recesses 22 ([Fig. 5]) or even additional flat surfaces. For example, one or more ribs can be formed on an external wall of the tower. These can be axial ribs. The additional elements can be formed on the winding support 12, in particular on one or more of the laminations 16. Of course, the reverse is also possible with one or more positioning ribs formed on the winding support 12.

[0103] Other examples of positioning elements can be formed by outgrowths 22'.

[0104] Figure 6 shows an alternative example of a winding support 12 of the stator assembly 5B. Only the differences from the previously described examples are detailed below.

[0105] According to this alternative, the winding support 12 comprises a stack of different sheets 16 or plates, in particular having at least two different types I, II of plates or sheets 16.

[0106] At least one type I of plates or sheets 16 can correspond to the embodiment previously described with reference to [Fig.5].

[0107] This first type I of plates or sheets 16 can for example be arranged in a lower part of the winding support 12 according to the orientation of the elements on the [Fig.6].

[0108] As an alternative or in addition, the winding support 12 may include a second type II of plates or sheets 16 different from those of the first type I.

[0109] The second type II of plates or sheets 16 can for example be arranged in an upper part of the winding support 12 according to the orientation of the elements on the [Fig.6].

[0110] The plates or sheets 16 of this second type II may each have: - one or more outgrowths 22', - one or more 20' eyelets which can be closed (as opposed to the open 20' eyelets of the 16' sheets of first type I).

[0111] The protrusions 22' and the assembly elements such as closed eyelets 20' can succeed one another alternately at the level of the theoretical inner circle Ci of the ring 125.

[0112] The protrusions 22' advantageously have a centering function. These protrusions 22' extend radially in projection with respect to the ring 125, in particular with respect to the theoretical inner circle Ci, towards the center or substantially the center of the ring 125, or more generally towards the winding support 12.

[0113] These protrusions 22' may have a rounded, or concave, shape towards the inside of the ring 125, or of the winding support 12.

[0114] The protrusions 22' can be dimensioned so that when the stator assembly 5B is assembled with the bearing carrier 13 (visible in [Fig.2]) there is a gap between the end of the protrusions 22' and the bearing carrier 13, in particular the tower, for centering with respect to the bearing carrier 13.

[0115] The 20' eyelets can serve to receive a fastening means such as a screw as previously described. In addition, the 20' eyelets can provide a rotational locking function.

[0116] These eyelets 20' can also form outgrowths for example rounded towards the inside / center of the ring 125 and forming a projection, radially, in relation to the ring 125, in particular in relation to the theoretical inner circle Ci of the ring 125.

[0117] In particular, the eyelets 20' may project more radially towards the inside / center of the ring 125 than the outgrowths 22'.

[0118] These eyelets 20' are advantageously dimensioned so as to come into contact with the bearing carrier 13, in particular the tower, and to prevent the stator assembly 5B from rotating relative to the bearing carrier 13. Additionally, the bearing carrier 13, more precisely the tower of the bearing carrier 13, may have respective recesses having a complementary shape to the eyelets 20'. Thus, through contact / cooperation of the eyelets 20' with such recesses, the stator assembly 5B is prevented from rotating relative to the bearing carrier 13.

[0119] Thus, by making the sheet metal(s) 16 with the rounded shape towards the inside (the center) of the winding support 12, in particular concave, at the level of the notch bottoms, on the outside side, or even also on the inside side, of the ring 125, it is possible to reduce the radial thickness of the ring 125 at least at the level of the bridges or links 124, without affecting the magnetic flux which passes through the winding support 12.

[0120] In addition, the winding support 12 with this inwardly rounded or concave shape of the links 124 and reduced radial thickness, offers a rigidity similar to a winding support according to the prior art with radially wider links 124 and whose ring has a convex outer circle.

Claims

Demands

1. Stator assembly (5B) for an electric motor (5) of a motor-fan unit (1) comprising a fan wheel (3), the electric motor (5) being configured to drive the fan wheel (3) in rotation, the stator assembly (5B) comprising: - a winding support (12) centered about an axis (A) and comprising a plurality of branches (121) extending radially with respect to the axis (A) of the winding support (12), the branches (121) delimiting in pairs a respective slot (122), and - a winding (14) comprising a plurality of windings (141), a winding (141) being formed around each branch (121), - characterized in that the slots (122) have a respective slot bottom (123) of generally rounded shape towards the inside of the support winding (12).

2. Stator assembly (5B) according to the preceding claim, wherein the slot bottoms (122) are generally concave in shape, with the concavity oriented towards the inside of the winding support (12).

3. Stator assembly (5B) according to any one of the preceding claims, wherein the winding support (12) comprises a link (124) between each pair of adjacent branches (121), and wherein the winding support (12) has at the links (124) a minimum cross-section greater than or equal to 40% of a minimum cross-section of a branch (121).

4. Stator assembly (5B) according to any one of the preceding claims, wherein the notches (122) delimited between two arms (121) of the winding support (12) are axially through.

5. Stator assembly (5B) according to any one of the preceding claims, wherein: - the winding support (12) comprises a ring (125) from which the arms (121) extend radially, the ring (125) having a central orifice and defining a theoretical inner circle (Ci) and a theoretical outer circle (Ce) such that the slot bottoms (123) lie within the outer circle (Ce), and in which - the ring (125) has at the level of the theoretical inner circle (Ci) rounded surfaces towards the inside of the ring (125), the rounded surfaces being opposite the bottoms of the notch (123).

6. Stator assembly (5B) according to any one of the preceding claims, wherein the winding support (12) comprises a bundle of laminations (16) axially superimposed on one another.

7. Stator assembly (5B) according to any one of the preceding claims, wherein the winding support (12) comprises at least one assembly member (20, 20') configured to cooperate with at least one fastening element, the assembly member (20, 20') being selected from a closed eyelet, an open eyelet, a recess, a clamp shape.

8. Stator assembly (5B) according to any one of the preceding claims, wherein the winding support (12) comprises at least one positioning element configured to cooperate with a complementary element on a motor support on which the stator assembly is intended to be mounted, the positioning element being selected from a rib, a tooth, a recess (22), a notch, an eyelet, an ear, a flat, a plate, a protrusion (22'), a protrusion.

9. Electric motor (5) in particular for a motor-fan unit (1), said motor (5) comprising a rotor (5A) and a stator assembly (5B) according to any one of the preceding claims.

10. Motor-fan unit (1), in particular of a motor vehicle, the motor-fan unit (1) comprising a fan wheel (3), an electric motor (5) according to the preceding claim configured to drive the fan wheel (3) in rotation, and a motor support (7), the stator assembly (5B) being mounted on the motor support (7).

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