Stator with pins connected by additive manufacturing

Abstract

Title of the invention: Stator with pins connected by additive manufacturing. The present invention relates to a stator (1) comprising a stator body (2) and a winding, the stator body (2) comprising a phase output face (4) and an opposite face (6), the winding comprising a plurality of pins (12), each pin (12) having at least one median segment (20) comprising a first end and a second end (26), the first end of the median segment (20) projecting from the phase output face (4) and the second end (26) of the median segment (20) projecting from the opposite face (6), the stator (1) comprising connecting portions (36) connecting the first ends and / or the second ends (26) of the median segments (20) of two pins (12), these connecting portions (36) being produced by additive manufacturing. Abstract figure: Figure 1

Description

Title of the invention: Stator with pins connected by additive manufacturing

[0001] The present invention relates to the field of rotating electrical machines such as alternators, alternator-starters or even electrical propulsion machines for motor vehicles, and more particularly the stators of such rotating electrical machines which comprise a winding made from conductive pins.

[0002] A rotating electrical machine comprises a shaft secured to a rotor and a stator arranged so as to rotate the rotor by means of a magnetic field. For this purpose, the rotor is for example provided with permanent magnets and the stator with an electric winding. The electric winding is supplied with electric current by means of a control module, so as to generate a rotating magnetic field at the electric winding. This rotating magnetic field makes it possible to drive the rotation of the rotor.

[0003] The stator winding can be achieved in different ways, and in particular by means of conductive pins which are inserted into the stator and are connected two by two to form a continuous electrical path. The connection of the conductive pins requires at least one twisting operation, which consists of twisting one of their ends. Each conductive pin then has an angular offset at this end, which will allow a welding operation to be carried out in order to associate it with the end of another conductive pin so as to ensure electrical continuity.

[0004] These twisting and welding operations are however complex and time-consuming, especially since they need to be repeated for each pin. The present invention aims to overcome this drawback by proposing a stator whose conductive pins are joined to each other by a simplified mechanism.

[0005] The main subject of the present invention is thus a stator comprising a stator body and a winding, the stator body comprising a phase output face, an opposite face and notches extending between these two faces, the winding comprising a plurality of pins, each pin having at least one median segment comprising a first end and a second end, this median segment being arranged in a notch, the first end of the median segment projecting from the phase output face and the second end of the median segment projecting from the opposite face, the stator comprising junction portions connecting the first ends and / or the second ends of the median segments of two pins, these joining portions being produced by additive manufacturing.

[0006] The stator according to the invention is intended to be integrated into a rotating electrical machine of an electric vehicle. This stator comprises a stator body which corresponds to a stack of laminations, and which extends, in a direction substantially parallel to an axis passing through its center, between a phase output face and an opposite face. From the phase output face to the opposite face extend notches formed radially in the stator body and which are open onto an internal housing of the stator within which a rotor can be inserted.

[0007] These notches are intended to receive a part of the stator winding, which is formed by conductive pins electrically connected to each other. The winding may further comprise, in addition to these pins which are standard connectors, neutral connectors or even phase output connectors.

[0008] These pins comprise at least one middle segment, or conductive segment, which extends at least partially within a notch. More specifically, a central portion of the middle segment extends within a notch while each of its ends extends beyond one of the faces of the stator body, with its first end projecting from the phase output face and its second end projecting from the opposite face. Preferably, these ends of the middle segments project from their respective faces by 3 to 4 mm. The first ends of the middle segments are arranged at a first longitudinal end of the pins, while their second ends are arranged at a second longitudinal end of these pins.

[0009] As mentioned above, the pins are electrically connected to each other. For this purpose, the stator comprises junction portions, also called junction waves, which provide the electrical connection between either two first ends of two separate pins, or two second ends of two separate pins. All of these junction portions for a given face of the stator constitute a bun.

[0010] Such junction waves are produced by additive manufacturing according to the invention, instead of being formed as in the prior art by welding operations of the longitudinal ends of the pins. In particular, the junction waves can be obtained by a three-dimensional printing operation, which allows targeted heating, for example via a laser source, of a material, here copper powder, to obtain a shape connecting the ends of two pins. The junction waves can also be obtained by projection of the copper powder onto these ends, grains forming this powder being made integral by successive layers of the ends via the intervention of a laser.

[0011] According to an optional characteristic of the invention, the joining portions com take return junction portions connecting the second ends of the middle segments of two pins.

[0012] In other words, among the junction portions included in the stator, some have the purpose of connecting the second end of the middle segment of a first hairpin to the second end of the middle segment of a second hairpin; these are return junction portions, which are therefore arranged at the level of the face opposite the phase output face.

[0013] According to an optional characteristic of the invention, each joining portion is formed in a single piece by a first edge, a second edge and an arch continuously connecting this first edge and this second edge.

[0014] The first edge and the second edge are each in contact with a first end or are each in contact with a second end of the middle segments.

[0015] The use of additive manufacturing makes it possible to obtain junction portions whose shapes would otherwise not be achievable with copper wire without using a welding operation.

[0016] According to an optional characteristic of the invention, the pins each comprise a single median segment.

[0017] This is a first embodiment of the pins, in which they have an I-shape.

[0018] According to an optional characteristic of the invention, the joining portions comprise connecting joining portions connecting the first end of the middle segment of one pin to the first end of the middle segment of another pin.

[0019] In the first embodiment which has just been mentioned, the connection junction portion here corresponds to a junction portion at the level of the phase output face, as opposed to the return junction portion which is arranged at the level of the opposite face.

[0020] According to an optional characteristic of the invention, the pins each comprise two median segments each having a first end and a second end, the two first ends of the median segments of a pin being joined to each other by a connecting portion formed of material with said median segments, at least one of the second ends of the median segments of said pin being connected to the second end of the median segment of another pin by one of the joining portions.

[0021] Such a feature corresponds to a second embodiment of the pins, in which they have a U-shape. According to this second embodiment, the first longitudinal end of a pin comprises the first end of a first median segment and the first end of a second median segment, which are joined by a connecting portion which is formed of material with these middle segments. The first middle segment, the connecting portion and the second middle segment thus form a single-piece assembly. The second longitudinal end of the hairpin comprises the second end of the first middle segment and the second end of the second middle segment, which are each connected to the second end of the middle segment of another hairpin via one of the joining portions, and more particularly one of the return joining portions, of the stator. The connecting portions are distinguished from these joining portions in that they are not produced by additive manufacturing but form a continuity in the material with the middle segments.

[0022] According to an optional characteristic of the invention, a portion of the median segments extending within the notch is covered with an insulating layer, at least one terminal portion of the ends of these median segments connected by a junction portion being devoid of insulating layer.

[0023] The junction portion here corresponds to a connection junction portion and / or to a return junction portion as mentioned above. The insulating layer is a layer of enamel which at least partially covers the middle segments, and in particular their central portion which extends within the notches. The terminal portion of the first end and / or of the second end is conversely devoid of this insulating layer, in order to allow the adhesion of the copper powder during the additive manufacturing operation. Such an end portion thus corresponds to a shoulder at the ends of the middle segments, which corresponds to a thickness of removed insulating layer.

[0024] According to one feature, a dimension of the terminal portion measured from the face of the stator body from which the end of the middle segment projects is between 0.5 and 5 mm.

[0025] Such a dimension is measured in a direction substantially parallel to a main direction of extension of the median segment, i.e. parallel to the axis of the stator.

[0026] According to one characteristic, the ends of the median segments connected by the junction portion have a surface whose roughness is between 0.8 and 3.2 μm.

[0027] According to a characteristic of the invention, the joining portion has a widening in the vicinity of the first edge and / or the second edge.

[0028] In other words, the joining portion has, in the vicinity of a free end forming the first edge and / or in the vicinity of a free end forming the second edge, a section greater than an equivalent section of the first end or the second end of the median segment of the pin. Here, the term “free end of the joining portion” means the end intended to be in contact with the first or second end of the middle segment. Such widening or flattening ensures better grip of the joining portion over the entire end of the middle segment of the pin, in particular by compensating for any positioning tolerances of the middle segments. The widening is, for example, 0.1 to 0.4 mm over a height of 1 to 5 mm.

[0029] According to another characteristic of the invention, the junction portion is covered with an insulating coating.

[0030] Such an insulating coating is added to the junction portion once it has been made integral with the pins by additive manufacturing; it may for example involve the addition of enamel by steam or dipping in an impregnation varnish, without this list being limiting. This insulating coating is distinct from the insulating layer present on the middle segments.

[0031] According to another characteristic, the joining portion is partially laminated.

[0032] Such a layered composition results from additive manufacturing. Here, "partially layered" means that the core of the joining portion is layered, whereas this is not the case for the insulating coating.

[0033] According to a characteristic of the invention, a porosity measured within the junction portion is greater than 1%.

[0034] Such porosity results from the additive manufacturing process, which consists of welding powder grains between which voids may remain.

[0035] According to another characteristic, each notch comprises an insulating material.

[0036] This insulating material is for example kapton, or another polyimide-based material. The insulating material is pressed against the walls delimiting the corresponding notch and it forms a housing within which one or more median segments arranged side by side are received. The insulating material may protrude from the phase output face and / or the opposite face over an axial dimension of between 0.5 and 4 mm; preferably, over between 1 and 2 mm.

[0037] The invention further relates to a method for manufacturing a stator as mentioned above, comprising a step of inserting the pins into the stator body, an impregnation step during which the position of the middle segments of the pins is fixed within the notches, an additive manufacturing step during which the stator body is embedded in copper powder which is heated to produce junction portions connecting two by two the first ends and / or the second ends of the middle segments of the pins, and a protection step during which at least the junction portions are covered with an insulating coating.

[0038] The step of inserting the pins is carried out so that their middle segment is arranged in a notch, the first end of this middle segment projecting of the phase output face and its second end protruding from the opposite face. The additive manufacturing step corresponds to the production of the junction portions by three-dimensional printing, these junction portions being subsequently covered with the insulating coating. During the protection step, the terminal portions of the ends of the middle segments are also covered with the insulating coating.

[0039] The method may further comprise, prior to the insertion step, a step of machining the ends intended to be connected by joining portions. The median segments have, at the end of this machining step, a reduced size compared to the median segments of the prior art, such a reduction in size resulting from a need to accommodate the joining portion. The machining step also allows the ends of all the pins to extend in the same plane.

[0040] According to one characteristic, the method comprises, prior to the step of inserting the pins, a step of inserting the insulating material into the notches.

[0041] According to another characteristic, the method comprises a step of depositing the insulating layer on at least part of the median segments of the pins between their first ends and their second ends.

[0042] The method may alternatively comprise a step of removing the insulating layer on the terminal portions of the ends of the middle segments intended to be connected by a joining portion. This removal step is for example a machining step which creates a shoulder on the first ends and / or the second ends of the middle segments of the pins. The removal step consists of locally removing the insulating layer on the terminal portions of the ends. The absence of an insulating layer on these terminal portions allows the joining portions to adhere.

[0043] According to another characteristic, during the additive manufacturing step, copper powder is heated to produce junction portions connecting two by two the second ends of the middle segments of the pins, the method comprising an additional additive manufacturing step during which copper powder is heated to produce junction portions connecting two by two the first ends of the pins.

[0044] Such a method corresponds to the manufacture of a stator comprising pins according to the first embodiment. Both the first ends and the second ends are here connected by junction portions, respectively return junction portions and connection junction portions. Prior to the additional additive manufacturing step, the method comprises a step of turning over the stator body, so as to successively position the opposite face and then the phase output face under the printer.

[0045] Other features, details and advantages of the invention will become more apparent clearly upon reading the description which follows on the one hand, and examples of embodiment given for informational and non-limiting purposes with reference to the attached drawings on the other hand, in which:

[0046] [Fig.l] illustrates, schematically, a stator according to the invention, pins of this stator being connected to each other by junction portions produced by additive manufacturing;

[0047] [Fig.2] illustrates, schematically, a pin of the stator of [Fig.l], this pin having an I-shape which corresponds to a first embodiment;

[0048] [Fig.3] illustrates, schematically, a pin of the stator of [Fig.l] having a U-shape, which corresponds to a second embodiment;

[0049] [Fig.4] illustrates, schematically, the pin according to the second embodiment inserted into a stator body;

[0050] [Fig.5] illustrates, schematically, a sectional view of the stator body in which is inserted a plurality of pins, ;

[0051] [Fig.6] illustrates, schematically, a sectional view of the stator body in which is inserted a plurality of pins, these pins being connected at one of their ends by connecting portions;

[0052] [Fig.7] illustrates, schematically, a perspective view of the stator body of the [Fig.5], the pins being connected by joining portions produced by additive manufacturing according to a first shape;

[0053] [Fig.8] illustrates, schematically, a perspective view of the stator body of [Fig.5], the pins being connected by junction portions produced by additive manufacturing according to a second shape.

[0054] The features, variants and different embodiments of the invention may be combined with each other, in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0055] In the figures, the elements common to several figures retain the same reference.

[0056] [Fig.l] thus illustrates, schematically, a stator 1 according to the invention. Such a stator 1 is intended to equip a rotating electrical machine of a vehicle, such a rotating machine having an axis X of rotation. By way of example, this rotating electrical machine may consist of an alternator, an alternator-starter or even an electrical propulsion machine of a hybrid or electric vehicle.

[0057] The stator 1 comprises a stator body 2 which extends, in a direction substantially parallel to the axis X, between two faces including a phase output face 4 and an opposite face 6.

[0058] The stator body 2 is crossed, from its phase output face 4 to its opposite face 6, by an internal housing 8 of substantially cylindrical shape which extends around the axis X. This internal housing 8 can receive a rotor of the electrical machine. Such a rotor can for example be a permanent magnet rotor, a squirrel cage rotor for an asynchronous machine, a rotor for a variable reluctance machine, a claw rotor or even a wound rotor for a synchronous machine, without this list being limiting of the invention.

[0059] The stator body 2 has notches 10 which correspond to radial indentations, such notches 10 being open onto the internal housing 8. These notches 10 extend from the phase output face 4 to the opposite face 6 and are configured to receive a winding of the stator 1, and more particularly a plurality of pins 12 participating in forming this winding. These pins 12 are conductive elements which allow the transmission of an electric current, and which participate in generating a magnetic field so as to drive the rotor in rotation. Each notch 10 here comprises an insulating element 14, positioned as a covering of the walls delimiting the notch and which constitutes a housing for receiving a pin. This insulating element 14 is for example obtained from polyimide.The insulating element 14 projects from the phase output face 4 and / or the opposite face 6 over a dimension of the order of 0.5 to 4 mm, preferably between 1 and 2 mm, such dimensions being measured parallel to the X axis. Such a projection is particularly visible in [Fig.4].

[0060] The pins 12 will now be described in detail. These pins 12 can alternatively have an I-shape, which corresponds to a first embodiment illustrated in [Fig.2], or a U-shape which corresponds to a second embodiment shown in [Fig.3]. Whatever the embodiment, each pin 12 extends between a first longitudinal end 16 and a second longitudinal end 18. When the pins 12 are received in the notches 10, their first longitudinal ends 16 are opposite the phase output face 4 while their second longitudinal ends 18 are opposite the opposite face 6.

[0061] Each pin 12 comprises at least one connector segment or median segment 20, which corresponds to a portion of the pin 12 which extends substantially parallel to the axis X when the stator is arranged within the stator body 2. This median segment 20 has a central portion 22 which extends within one of the notches 10, this central portion 22 being bordered at the level of the phase output face 4 by a first end 24 of the median segment 20 and at the level of the opposite face 6 by a second end 26 of this median segment 20. The first end 24 corresponds more precisely to a part of the middle segment 20 projecting from the phase output face 4, while the second end 26 corresponds to its part which projects from the opposite face 6. Preferably, the first and second ends 24, 26 of a middle segment project from their respective face 4, 6 by 3 to 4 mm. It is further understood that the first end 24 of the middle segment 20 is in the vicinity of the first longitudinal end 16 of the pin 12, the second end 26 being in the vicinity of its second longitudinal end 18.

[0062] The pins 12 according to the first embodiment, i.e. the I-shaped pins 12, have a single median segment 20 bordered by its first end 24 and its second end 26. Such pins 12 are shown in FIGS. 1, 2, 5, 7 and 8. Conversely, the pins 12 according to the second embodiment, i.e. the U-shaped pins 12 which are illustrated in FIGS. 3, 4 and 6, comprise two median segments 20A, 20B which each have a first end 24 and a second end 26. In this second embodiment, the first end 24 of one of the median segments 20A, 20B of a given pin 12 is joined to the first end 24 of the other of the median segments 20A, 20B by a connecting portion 28. Such a connecting portion 28 is formed of material with the middle segments 20A, 20B.This connecting portion 28, which corresponds to the first longitudinal end 16 of the pin 12 according to the second embodiment, is particularly visible in FIGS. 3, 4 and 6. The connecting portion 28 has an offset between the two median segments 20A, 20B, which in particular makes it possible to house the two median segments in different notches of the stator body and in different radial positions from one notch to the other.

[0063] As mentioned previously, the middle segments 20 of the pins 12, and more precisely their central portions 22, are inserted into the notches 10 covered with the insulating material 14. These notches 10 can also receive other types of conductive segments participating in the winding, and in particular phase current inputs and outputs 30. The phase current inputs and outputs 30, visible in FIGS. 6 to 8, have axial extensions at the level of the phase output face 4.

[0064] In the example illustrated, and as can be seen in particular in FIGS. 4 and 6, the pins 12 are arranged within the notches 10 in two rows, with a first row or inner row 32 closest to the axis X, and a second row or outer row 34 further from this axis X and arranged concentrically around the inner row 32. Each notch 10 can therefore receive two median segments 20, with a median segment 20 arranged in the inner row 32 and a median segment 20 arranged in the outer row 34. It would however be possible to envisage, without departing from the scope of the invention, a stator body 2 having four, six, eight or even ten rows arranged radially around each other. In the presence of the pins 12 according to the second embodiment, their first median segment 20A is arranged in the internal row 32 and their second median segment 20B is arranged in the external row 34 or vice versa. The first median segment 20A and the second median segment 20B are however not received by the same notch 10; they are arranged at a given number of notches 10 apart, preferably between one and eight notches 10, even more preferably between five and seven notches. [Fig.4] shows an embodiment where the first median segment 20A and the second median segment 20B of a pin 12 are arranged in two separate notches 10 separated from each other by six notches 10.As mentioned previously, such a gap between the middle segments 20A, 20B is dependent on a shape of the twist of the connecting portion 28 at the level of the phase output face 4.

[0065] According to the invention, the stator 1 comprises junction portions 36 produced by additive manufacturing which connect the first ends 24 and / or the second ends 26 of the median segments 20 of two pins 12. These junction portions 36 are for example obtained by heating grains of copper powder in order to weld them to each other.

[0066] The junction portions 36 comprise, according to the embodiments, connection junction portions 36A which each connect the first end 24 of the middle segment 20 of a given pin 12 to the first end 24 of the middle segment 20 of another pin 12, and / or return junction portions 36B which each connect the second end 26 of the middle segment 20 of a given pin 12 to the second end 26 of the middle segment 20 of another pin 12. It is thus understood that the connection junction portions 36A correspond to the junction portions 36 arranged within the stator 1 at the level of the phase output face 4, the return junction portions 36B constituting the junction portions 36 arranged opposite the opposite face 6.

[0067] In the presence of pins 12 according to the first embodiment, the stator 1 according to the invention has both connection junction portions 36A and return junction portions 36B, as shown in FIGS. 7 and 8. Such pins 12 are thus connected to each other by parts produced by additive manufacturing both at the phase output face 4 and the opposite face. Conversely, in the presence of pins 12 according to the second embodiment, the stator 1 has only return junction portions 36B, since the first ends 24 of the pins 12 are already connected at the phase output face 4 by the connecting portions 28.

[0068] Whether it is a connection junction portion 36A or a portion of return junction 36B, each of the junction portions 36 is partially laminated. Each junction portion 36 thus has a laminated core resulting from successive heating operations of copper powder grains to bond them to each other. This laminated core may also be covered with an insulating coating, for example an enamel or a varnish. A porosity measured within the junction portion 36, and more specifically its laminated core, is greater than 1%.

[0069] Each joining portion 36 is formed in one piece by a first edge 38, a second edge 40 and an arch 42 continuously connecting this first edge 38 and this second edge 40. Here, the term "in one piece" means that the joining portion 36 is devoid of weld beads. Two different shapes of joining portions 36 are shown in Figures 7 and 8, with a joining portion 36 having a rounded arch 42 in [Fig.7] and a joining portion 36 having a tapered arch 42 in [Fig.8].

[0070] Each of the first edge 38 and the second edge 40 is intended to come into contact with an end 24, 26 of the median segment 20 of a pin 12. It is understood that the first edge 38 is integral with a first end 24 of a given pin 12 while the second edge 40 is integral with the first end 24 of another pin 12 when the junction portion 36 is a connection junction portion 36A, and that alternatively the first edge 38 is integral with a second end 26 of a given pin 12 while the second edge 40 is integral with the second end 24 of another pin 12 when the junction portion 36 is a return junction portion 36B.Whatever the shape of the joining portion 36, it must have a twist so that a point of the arch 42 extends mainly in a plane arranged between a plane in which the first edge 38 extends and a plane in which the second edge 40 extends, this twist allowing the joining of ends 24, 26 of median segments 20 arranged in different notches 10.

[0071] In order to best secure itself with, depending on the embodiments, the first or second ends 24, 26 of the median segments 20 of the pins 12, the joining portion 36 is made so as to have a widening, that is to say a local increase in the section in a plane perpendicular to the axis X whether in the vicinity of the first edge 38, in the vicinity of the second edge 40, or in the vicinity of each of the two edges. The widening, although not shown in the figures, can be progressive so that the section of the joining portion 36 increases, over an axial dimension of 5 mm for example, as the first edge 38 and / or the second edge 40 move closer together.

[0072] The middle segments 20 of the pins 12 are machined to facilitate the adhesion and holding of the copper powder forming a junction portion 36 obtained by additive manufacturing according to the invention. More particularly, an end portion 44 of the ends 24, 26 intended to be connected by a junction portion 36 is devoid of an insulating layer while such an insulating layer covers the central portion 22 of the middle segments 20 which extends within the notches 10. The machining mentioned above consists of a removal operation, for example by cutting, of the insulating layer on said terminal portion 44 of the ends 24, 26. The terminal portions 44 of the ends 24, 26 of the middle segments 20 being thus devoid of an insulating layer, a shoulder 46 is formed at the junction of a terminal portion and the central portion. Such a shoulder 46 is particularly visible in FIGS. 2 and 3. An axial dimension of the terminal portion 44 is between 0.5 and 5 mm.Additionally and always with a view to facilitating their attachment to the joining portions 36, the ends 24, 26 of the middle segments 20 of the pins 12 intended to be connected by one of these joining portions 36 have a surface whose roughness is between 0.8 and 3.2 μm.

[0073] A method of manufacturing the stator 1 according to the invention will now be described in detail. Such a manufacturing method begins with a step of manufacturing the stator body 2, for example by superimposing sheets with cutouts which form the notches 10 once the stack of sheets has been obtained. This step of manufacturing the stator body 2 continues with a step of inserting the insulating element 14 into the notches 10. This insulating element 14 can make it possible to radially close the notches 10 at the level of their portion closest to the axis X.

[0074] The method for manufacturing the stator 1 further comprises a step of manufacturing the pins 12. This manufacturing step includes, in particular, for the second embodiment of the pins 12 in which they have a U shape, twisting the pins 12 at their connecting portions 28. Whether for the first embodiment or the second embodiment of the pins 12, the manufacturing step includes a sub-step during which the insulating layer is deposited on at least a portion of the middle segments 20 of the pins 12 between their first ends 24 and their second ends 26. This sub-step, which is therefore a sub-step of depositing an insulating layer, is optionally followed by a sub-step of removing this insulating layer on the terminal portions 44 of the first and second ends 24, 26 of the middle segments 20 intended to be connected by junction portions 36.The removal sub-step results in the formation of the shoulder 46 on the middle segments 20. It is thus understood that the removal sub-step is necessary when the insulating layer has been deposited, during the deposition sub-step, uniformly between the first ends 24 and the second ends 26 of the middle segments 20 of the pins 12, the terminal portions 44 having to be devoid of this insulating layer to allow the adhesion of the joining portions 36.

[0075] Once the pins 12 have been manufactured, the manufacturing method continues with a step of inserting these pins 12 into the stator body 2. The stator body 2 can for this purpose be held in position by a holding tool 48, notably visible in FIGS. 1 and 5 to 8. Such a holding tool 48 advantageously has a hollowed-out portion 50 within which the winding projecting from one or the other of the phase output face 4 and the opposite face 6 can extend when the stator body 2 is arranged on the holding tool 48. This hollowed-out portion 50 is particularly visible in the sectional view of [Fig. 6].

[0076] At the end of the insertion step, the pins 12 are arranged in the stator body 2 in such a way that the central portions 22 of their median segments 20 are each arranged in a notch 10. In this way, the first ends 24 project from the phase output face 4 and the second ends 26 project from the opposite face 6. Once the pins 12 are correctly positioned in the stator body 2, their position within the notches 10 is fixed by an impregnation step during which the median segments 20 are covered with a fixing material.

[0077] If necessary, an additional machining operation is carried out to adjust the dimension of the segments projecting from the stator body and / or to adjust the surface roughness of the ends of the segments.

[0078] The manufacturing method then comprises an additive manufacturing step during which the stator body 2 is embedded in copper powder, grains of which are heated locally, for example via a laser beam, to produce junction portions 36 connecting two by two the first ends 24 and / or the second ends 26 of the middle segments 20 of the pins 12. Such an additive manufacturing step involves a three-dimensional printer 52, shown in [Fig. 6] in a rectangular schematic form, which allows heating of the grains of the copper powder until a desired shape of the junction portion 36 is obtained.The adhesion of the copper powder to the ends 24, 26 of the middle segments 20 of the pins 12 is facilitated where appropriate on the one hand by the removal of the insulating layer from the terminal portions 22 carried out during the aforementioned removal step, and on the other hand by the widening of the first edge 38 and / or the second edge 40 of the junction portion 36.

[0079] As has been specified, the additive manufacturing step can take place on the first ends 24 and / or on the second ends 26. Such a distinction depends on the embodiment of the pins 12. Indeed, in the presence of pins 12 according to the first embodiment there is both an additive manufacturing step for the production of junction portions 36 at the second ends 26 of the median segments 20 of the pins 12, i.e. return junction portions 36B, and an additional additive manufacturing step for producing junction portions 36 at the first ends 24 of the middle segments 20 of the pins 12, i.e. connection junction portions 36A. The pins 12 will therefore be connected to each other by junction portions 36 produced by additive manufacturing both at the phase output face 4 and at the opposite face 6. Between these two additive manufacturing steps, the manufacturing method comprises a step of turning the stator body 2 over on the holding tool 48. This makes it possible to successively position the opposite face 6 and then the phase output face 4 under the three-dimensional printer 52.

[0080] Conversely, in the presence of pins 12 according to the second embodiment, a single additive manufacturing step is sufficient, this resulting in the production of junction portions 36 at the second ends 26 of the median segments 20 of the pins 12, namely return junction portions 36B at the level of the opposite face 6. It is in fact not necessary to carry out an additive manufacturing step at the level of the phase output face 4, since the first ends 24 are already connected to each other there by the connecting portions 28.

[0081] Whether for the first embodiment or the second embodiment, the manufacturing method ends with a protection step during which the junction portions 36 are covered with the insulating coating. The terminal portions 44 of the ends 24, 26 of the middle segments 20 can also undergo such a protection step.

[0082] The present invention thus proposes a stator in which pins are connected to each other by joining portions produced by additive manufacturing, such joining portions making it possible to facilitate the machining of the stator, in particular by simplifying the steps of twisting the pins and the steps of inserting the winding that they help to form within a body of the stator.

[0083] The present invention cannot, however, be limited to the means and configurations described and illustrated here and it also extends to any equivalent means and configuration as well as to any technically operative combination of such means.

Claims

Claims

1. Stator (1) comprising a stator body (2) and a winding, the stator body (2) comprising a phase output face (4), an opposite face (6) and notches (10) extending between these two faces (4, 6), the winding comprising a plurality of pins (12), each pin (12) having at least one middle segment (20) comprising a first end (24) and a second end (26), this middle segment (20) being arranged in a notch (10), the first end (24) of the middle segment (20) projecting from the phase output face (4) and the second end (26) of the middle segment (20) projecting from the opposite face (6), the stator (1) comprising junction portions (36) connecting the first ends (24) and / or the second ends (26) of the middle segments (20) of two pins (12), these joining portions (36) being produced by additive manufacturing,each joining portion (36) being formed in one piece by a first edge (38), a second edge (40) and an arch (42) continuously connecting this first edge (38) and this second edge (40), the joining portion having a widening in the vicinity of the first edge (38) and / or the second edge (40).,

2. Stator (1) according to the preceding claim, in which the junction portions (36) comprise return junction portions (36B) connecting the second ends (26) of the middle segments (20) of two pins (12).

3. Stator (1) according to any one of the preceding claims, wherein the pins (12) each comprise a single middle segment (20).

4. Stator (1) according to the preceding claim, wherein the junction portions (36) comprise connection junction portions (36A) connecting the first end (24) of the middle segment (20) of one pin (12) to the first end (24) of the middle segment (20) of another pin (12).

5. Stator (1) according to any one of claims 1 or 2, wherein the pins (12) each comprise two middle segments (20) each having a first end (24) and a second end (26), the two first ends (24) of the middle segments (20) of a pin (12) being joined to each other by a connecting portion (28) formed of material with said middle segments (20), at least one of the second ends (26) of a middle segment (20) of said pin (12) being connected to the second end (26) of the middle segment (20) of another pin (12) by one of the joining portions (36).

6. Stator (1) according to any one of the preceding claims, in which a portion of the middle segments (20) extending within the notch (10) is covered with an insulating layer, at least one terminal portion (44) of the ends (24, 26) of these middle segments (20) connected by a junction portion (36) being devoid of insulating layer.

7. Stator (1) according to the preceding claim, wherein a dimension of the terminal portion (44) measured from the face (4, 6) of the stator body (2) from which the end (24, 26) of the middle segment (20) projects is between 0.5 and 5 mm.

8. Stator (1) according to any one of the preceding claims, wherein the ends (24, 26) of the middle segments (20) connected by the joining portion (36) have a surface whose roughness is between 0.8 and 3.2 pm.

9. Stator (1) according to any one of the preceding claims, wherein the junction portion (36) is covered with an insulating coating.

10. Stator (1) according to any one of the preceding claims, wherein the joining portion (36) is partially laminated.

11. A method of manufacturing a stator (1) according to any one of the preceding claims, comprising a step of inserting the pins (12) into the stator body (2), an impregnation step during which the position of the middle segments (20) of the pins (12) is fixed within the notches (10), an additive manufacturing step during which the stator body is embedded in copper powder which is heated to produce junction portions (36) connecting two by two the first ends (24) and / or the second ends (26) of the middle segments (20) of the pins (12), and a protection step during which at least the junction portions (36) are covered with an insulating coating.

12. Method of manufacturing a stator (1) according to the preceding claim in combination with claim 6, comprising a step of depositing the insulating layer on at least a portion of the median segments (20) of the pins (12) between their first ends (24) and their second ends (26).

13. Method for manufacturing a stator (1) according to any one of claims 11 and 12 in combination with claim 4, wherein during the additive manufacturing step copper powder is heated to produce junction portions (36) connecting two by two the second ends (26) of the middle segments of the pins (12), the method comprising an additional additive manufacturing step during which copper powder is heated to produce junction portions (36) connecting two by two the first ends (24) of the pins (12).

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