FR3091059A1 - Rotating electric machine stator body - Google Patents

Abstract

The subject of the present invention is a stator body for a rotary electrical machine comprising a series of notches (3) arranged around an axis of the stator (1), at least one notch (3) being lined with an insulating envelope (5) having at least one fold zone (53) to match the shape of the notch (3), characterized in that the insulating envelope (5) comprises microperforations (52) arranged linearly so as to define the at least one fold zone (53) of the insulating envelope (5). Figure for the abstract: Figure 3b

Description

Description

Title of the invention: Rotating electric machine stator body

The present invention relates to a rotary electrical machine such as an alternator or an alternator starter for a motor vehicle. The invention relates more particularly to a rotary electrical machine comprising a stator winding made from conductive elements.

A rotary 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, the rotor is provided with permanent magnets and the stator with an electric winding. The electric winding is supplied with electric current through a control module, so as to generate a rotating magnetic field, in order to drive the rotation of the rotor provided with permanent magnets.

It is known to wind the stator by means of pins electrically connected to each other. The stator has a body provided with radial notches open at one end to receive phase windings formed by sets of pins connected to each other. The phase windings are polyphase windings, connected in star or triangle, whose phase inputs and outputs are connected to an electronic control module.

The pins comprise at least one branch capable of being housed in a notch of the stator and whose axial ends, protruding axially on either side of the notch considered, are configured to make the link with a neighboring pin, at least one branch extends into another notch of the stator. The connection of each pin thus generates continuity in the winding, from one notch to another. Each notch is thus filled with pin segments, arranged one behind the other according to the radial dimension of the notch.

During the insertion of the conductive segments into each of the notches, from an inner diameter to an outer diameter of the stator, the possible contact of the segments with the edges delimiting the entry of the notch can cause degradation of the copper enamel.

In order to avoid a short circuit between the electric winding and the stator body, an insulator is installed in the notches of the stator, so that the electric winding and the stator body are excluded from any contact. The insulator may in particular be in the form of a sheet of insulating paper to which a shape substantially complementary to that of the notch is given.

This shape given to the sheet of insulating paper can be obtained by means of an appropriately shaped matrix which is slid inside a sheet and against which the sheet is pressed.

Such a matrix solution is not completely satisfactory in that it can be difficult to form from the insulating sheet an envelope with well defined edges in the fold zones. However, in order to obtain optimal electrical insulation, it is desirable that said envelope formed from the insulating sheet closely matches the shape of the notch in order to avoid asymmetries.

Other manufacturing processes can be implemented, such as hot deformation of paper, but it has been observed that heating the insulating paper could alter the mechanical properties of the insulator by weakening the fold areas.

The present invention is part of this context and aims in particular to solve the drawbacks described below.

The invention relates to a stator body for a rotary electrical machine comprising a series of notches arranged around an axis of the stator, at least one notch being lined with an insulating envelope having at least one fold zone to match the shape of the notch, characterized in that the insulating envelope comprises microperforations arranged linearly so as to define the at least one fold zone of the insulating envelope.

Such a characteristic of the insulating envelope, that is to say the fact of producing the fold zones at the level of a microperforation line, thus makes it possible to obtain more angular folds, so that the folds better fit the corners of the notch. In addition, the location of the fold zones is more precise, since it is defined directly on the sheet participating in forming the insulating envelope and not by means of a matrix.

Each microperforation, according to the invention defining a fold to be given to the sheet to form the insulating envelope, forms with a plurality of other microperforations an alignment corresponding to a fold zone, the microperforations being arranged in relation to each other. to the others so that each of the microperforations is disposed at a non-zero distance from the neighboring microperforation.

According to the invention, the microperforations have a diameter of less than 0.7mm.

In order to obtain microperforations of such a diameter less than 0.7 mm, they are advantageously produced by laser perforation, making it possible to define sharp and precise microperforations.

The notches of the stator body extend over the entire axial dimension of the stator body and they are configured to receive an electrical winding formed of a plurality of conductive elements housed in the notches in a through manner.

According to a characteristic of the invention, the electric winding of the stator is covered with an impregnation varnish making it possible to protect the winding once the rotary electric machine has been assembled and in operation, the impregnation varnish also taking part in increase the electrical insulation between the electrical winding and the stator body. The varnish also has the function of guaranteeing the mechanical strength of the conductors therebetween, as well as the mechanical strength of the entire electrical winding of the stator in the sheet package.

According to the invention, the insulating envelope comprises perforations formed outside the fold zones and having a diameter greater than that of the microperforations.

The perforations have a larger diameter than the microperforations so that the impregnation varnish present on the electric coil can migrate towards the walls delimiting the notches, passing through these perforations

According to the invention, at least part of the microperforations is arranged so as to form alignments parallel to the axial direction of the stator.

It is understood that the part of the microperforations which form an alignment in the axial direction of the stator participate in particular in forming the bending zones configured to cooperate with the corners of the notch.

According to the invention, at least part of the microperforations is arranged so as to form alignments parallel to a radial direction of the stator.

The microperforations aligned in the radial direction of the stator are more particularly arranged in the vicinity of an axial end of the insulating envelope and they make it possible to define a folding of the sheet capable of flaring the axial end of the insulating envelope . Such a characteristic facilitates the insertion into the notch, in an axial direction, of the conductive elements, for example pins, forming the coil.

According to the invention, the insulating envelope is made of a polyester or polymer type material.

Materials of the polymer and polyester type allow the deformation of the insulation sheets to conform them in a complementary manner to the shape of the notches, while offering acceptable electrical insulation.

According to a characteristic of the invention, the notch comprises a bottom wall and an open end opposite the bottom wall, and the insulating envelope is folded so as to have, in a transverse plane perpendicular to the 'axis of the stator, a closed profile, so that this insulating envelope partitions the open end of the notch.

In this configuration, the insertion of the conductive elements in the notches is carried out in the axial direction of the stator.

According to a characteristic of the invention, the insulating envelope can be folded so as to have, in a transverse plane perpendicular to the axis of the stator, an open profile, and the insulating envelope can comprise in this context edges delimiting the opening of the profile which are perforated edges. It is understood that by perforated edge, it is intended to protect that the envelope has been cut along a line defining the edge, the line being formed by alignment of microperforations in accordance with which has been described above. The fact that the fold here results in a tear in the envelope along this fold line implies the presence of an irregular edge due to the remaining part of the microperforations. It is intended in this context that the opening of the profile of the insulating envelope corresponds to the open end of the notch.

According to one embodiment of the invention, a partition is inserted into the open end of the notch in order to block the conductive elements in the notch.

The invention also relates to a process for obtaining a stator body for a rotary electrical machine as just described, with a plurality of insulating envelopes with open profile. The method is such that an insulating sheet is folded so as to form a unit comprising in one piece several insulating envelopes capable of being housed respectively in one of the notches of the stator body, and the method of obtaining comprises in addition to a step of cutting each intermediate sheet forming in said assembly a connection between two insulating envelopes. According to the invention, the cutting step is performed once the insulating envelopes in position in the notches so as to release the inner faces of the teeth formed between the notches.

Furthermore, provision may be made for the cutting step to take place only once the insulating envelopes and the conductors in position in the notches, so as to provide an additional advantage in that it is thus protected. the conductors from any direct contact with the sheet bundle when the conductors are inserted into the notches, and that this avoids degrading the enamel of the conductors during their insertion.

It is understood that the microperforations of each insulating envelope arranged linearly in the axial direction and in the vicinity of the open end of the notch in which is housed the insulating envelope will allow to clearly tear the intermediate sheet positioned on the face inside of the stator teeth, so that no insulating film residue crosses the rotating magnetic field generated between the stator and the rotor. The intermediate sheet is all the easier to tear that the insulating envelopes, and if necessary the conductors, are already in position in the notches.

The invention also covers a rotary electric machine comprising at least one stator according to the preceding characteristics.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below for information only, in relation to the drawings in which:

[Fig.l] is a general perspective view of a stator according to the invention, showing a stator body with an electric winding in continuous corrugated winding;

[Fig.2] is a radial sectional view of the stator of [Figure 1], showing the arrangement of the electrical winding in notches in the stator body, a notch being devoid of conductive element retaining partitions in the notch;

[Fig.3a] and [Figure 3b] are perspective views of an insulation sheet provided, according to a first embodiment of the invention, to be disposed in a notch in the stator body illustrated in [Figure 4], [Figure 3a] illustrating the sheet before folding and [Figure 3b] illustrating the sheet in its folded form capable of being arranged in a notch;

[Fig.4] is a view similar to that of [Figure 2] with insulating envelopes as illustrated in [Figure 3b] and respectively inserted into a notch in the stator body, a notch being devoid an insulating jacket for the example;

[Fig.5] is a perspective view of the insulating jacket according to a second embodiment of the invention, adapted to be disposed in a notch in the stator body illustrated in [Figure 2];

[Fig.6a] is a perspective view illustrating a third alternative embodiment of the invention according to which a plurality of insulating envelopes is adapted to be inserted simultaneously in the notches of the stator;

[Fig.6b] is a perspective view of part of the insulating jacket from the folded sheet of [Figure 6a], torn after insertion into the notches in the stator body.

It should first be noted that the figures show the invention in detail to implement the invention, said figures can of course be used to better define the invention if necessary.

[Fig.l] illustrates a stator 1 of a rotating electric machine, which can in particular, but not limited to, be implemented in a motor vehicle, especially in the case of application of alto-starters in which, in an alternator mode, the rotating electrical machine transforms mechanical energy into electrical energy and in a motor mode, it transforms electrical energy into mechanical energy.

The stator 1 comprises a stator body 2 formed of a pack of sheets and which extends around an axis of revolution R of the stator. In the following detailed description, the terms radial / axial and interior / exterior refer to the axis of revolution R of the stator 1.

The stator body 2 comprises notches 3 passing through the stator body 2 axially and an electric coil 4 making it possible to generate, in motor mode, a rotating magnetic field capable of generating a rotation of a rotor, not shown here, for example provided with permanent magnets and arranged inside the stator.

The notches 3 have a trapezoidal shape as illustrated in the radial sectional view of [fig.2]. The notches 3 are formed from the internal wall of the stator so that they comprise an open end 32 towards the interior of the stator 1 and a bottom wall 31 facing the open end 32. A first radial wall 33a and a second radial wall 33b participate in delimiting the notch, each extending substantially parallel in a radial direction of the stator.

The first radial wall 33a and the second radial wall 33b define with the bottom wall 31 respectively a first corner 34a and a second corner 34b of the corresponding notch.

As illustrated in particular in [fig.2], the open end 32 allows the insertion of conductive elements 41 forming the electrical winding 4 inside the corresponding notch 3, the insertion is in the radial direction of the stator 1 in the direction of the bottom wall 31. More particularly, in the case of an electric coil 4 formed by a plurality of waves connected together at the level of the front and rear chignon visible on the [ Figure 1], each wave forming the conductive element mentioned above and passing axially through the stator body, extending in a notch 3.

According to the embodiment illustrated in [fig.2], each of the notches 3 comprises twelve conductive elements 41. Advantageously, the conductive elements 41 are aligned in two series of radial direction, thereby optimizing the space of the notches 3.

In addition, according to the invention, the conductive elements 41 of the electric winding 4 are covered with an insulating varnish so that it diffuses on the radial walls 33 and the bottom wall 31 of the notch 3.

So that the conductive elements 41 remain in place in the notches 3, partitions 6 are positioned in the open ends 32 of the notches 3, preventing the output of the conductive elements 41 from the notches 3. The partitions 6 extend as follows the axial direction of the stator 1 and have dimensions capable of covering the open end 32 of the notch 3.

Teeth 8 extend radially between each of the notches 3 of the stator body 2, so that the stator body is an alternation of notches and teeth between which the stator winding is arranged. Each of the teeth 8 has an inner face 9 facing the center of the stator and which is tangentially extended by two flanges 10 extending respectively across one of the two notches surrounding said tooth.

The flanges 10 extend across the open ends 32 of the notches 3 without however partitioning them in order to allow the insertion of the conductive elements 41 in the notches 3. The first radial wall 33a and the second radial wall 33b then go define with the edges 10 respectively a third corner 34c and a fourth corner 34d.

The flanges 10 will also allow the partitions 6 to be held in the open ends 32 once the conductive elements 41 are inserted in the notches 3.

Insulating envelopes 5 are inserted into the notches 3, between the walls defining the notch, namely the radial walls 33a, 33b and the bottom wall 31 and the conductive elements 41. The insulating envelopes 5 have the function of '' provide electrical insulation between the electrical winding 4 and the stator body 2 and thus avoid possible short circuits.

In the following detailed description, an insulating envelope 5 according to a first embodiment of the invention will be described with reference to [fig.3a] showing an insulation sheet before folding, [Figure 3b] showing the insulating jacket of [Figure 3a] after folding the insulation sheet and [Figure 4] showing the insulating jacket of [Figure 3b] inserted in the notch 3.

The insulating envelope 5 is in the form of a flat surface comprising microperforations 52 which are distinguished by their arrangement on the sheet. Thus, the insulating envelope comprises first microperforations 52a which are aligned in the axial direction of the stator and second microperforations 52b which are aligned in the radial direction of the stator. According to the invention, the microperforations 52 have a diameter of less than 0.7mm.

The first microperforations 52a are spaced apart from one another by a non-zero distance and are configured to define first folding zones 53a of the insulating envelope 5. The first folding zones 53a make it possible to fold the insulating envelope 5 according to predefined areas. We understand the advantage of such a characteristic since the following folding of the first microperforations 52a makes it possible to obtain more angular and more precise folds so that the insulating envelope 5 best matches the shape of the notch 3 and in particular the corners 34 of the notch.

The second microperforations 52b are positioned in the vicinity of an axial end 51 of the insulating envelope 5 and they are configured to define a second fold zone 53b of the insulating envelope 5. When the insulating envelope 5 is positioned in the notch 3 as illustrated in [fig.4], the axial end 51 remains outside the notch 3. Thus, when the conductive elements 41 are inserted in the notches 3 in an axial direction, the second microperforations 52b will make it possible to flare the axial end 51 of the insulating envelope 5, facilitating the insertion of the conductive elements.

Once folded along the first fold zones 53a, the insulating envelope 5 takes the form of a quadrilateral with four first fold zones 53a as illustrated in [fig.3b]. In other words, the insulating envelope is folded so as to have, in a transverse plane perpendicular to the axis of the stator, a closed profile.

We can separate the insulating jacket 5 into four separate sheets. First of all, a bottom sheet 56, configured to cooperate with the bottom wall 31 of the notch 3 and an internal sheet 59 radially opposite to the bottom sheet 56 and configured to be positioned in the open end 32 of the 'notch 3. Between the internal sheet 59 and the bottom sheet 56 extend a first radial sheet 58a and a second radial sheet 58b. It will then be understood that the first radial sheet 58a and the second radial sheet 58b are configured to be opposite respectively the first radial wall 33a and the second radial wall 33b of the notch 3.

The joins of the bottom sheet 56 with the first radial sheet 58a and the second radial sheet 58b respectively form a first sheet corner 57a and a second sheet corner 57b, able to cooperate with the first and second corners 34a and 34b of the notch as previously mentioned. The joints of the internal sheet 59 with the first radial sheet 58a and the second radial sheet 58b respectively form a third sheet corner 57c and a fourth sheet corner 57d, able to cooperate with the third and fourth corners 34c and 34d. The sheet corners 57 are then configured to cooperate with the corners 34 of the notch as illustrated in [fig.4].

We then understand the advantage of the first fold zones 53a defined by the first microperforations 52a since they make it possible to obtain angular sheet corners 57 which conform to the angular shape of the bottom corners 34 of the notch 3 as illustrated in [fig.4]. Such a characteristic optimizes the covering of the walls 31, 33 of the notch 3, thus ensuring better electrical insulation by covering and optimal filling of the notch by the conductive elements 4L [0064] The [fig.5] illustrates a variant embodiment of the insulating envelope 5, which differs from the above in particular in the form of folding of the insulating envelope 5 and in the presence of perforations, of dimensions and function different from those of the microperforations previously mentioned.

First, it should be noted that the insulating envelope 5 differs here from what has been previously described in that it has a profile, in a transverse plane, of open section, in that it does not have an internal sheet. Here the insulating envelope 5 comprises the first fold zones 53a defining the first sheet corner 57a and the second sheet corner 57b but also first fold zones 53a formed on the first radial sheet 58a and the second radial sheet 58b. In accordance with the invention and with what has been described above, these different fold zones 53a are produced along lines defined by a plurality of first microperforations 52a aligned with each other.

The first two fold zones 53a of the radial sheets 58 are positioned facing one another. An advantage of these first fold zones 53a of the radial sheets 58 is that they participate, when the insulating envelope is in the notch and that the conductive elements 41 are also inserted in the notch and push back towards the first radial walls. bending zones of the radial sheets, to generate a spring effect which tends to mechanically press the first sheet corner 57a and the second sheet corner 57b in the corresponding corner of the notch.

Furthermore, according to the alternative embodiment illustrated in [fig.5], the insulating envelope 5 includes perforations 54 formed outside the fold areas 53, visible in Figures 3a and 3b. The perforations 54 are distinguished from microperforations 52 in that they have a diameter strictly greater than the diameter of microperforations 52.

The perforations 54 have the function of allowing the diffusion of the impregnation varnish, contained on the conductive elements at the time of their insertion, on the bottom wall and the radial walls of the notch. A diameter of these perforations can be understood, for example, between 0.7 mm and 1 mm, it being understood that the perforations can be distinguished as having a larger diameter than that of microperforations.

Finally, the insulating jacket 5 illustrated in [fig.5] has an opening. The presence of this opening allows the insertion of the conductive elements 41 into the notch 3 via the open end 32 from an internal diameter 9 to an external diameter of the stator body 2, the conductive elements filling the notch 3.

We will now describe a third alternative embodiment of the invention with reference to Figures 6a and 6b, as well as a process for obtaining a stator body fitted with insulating envelopes according to this third variant. Here, several insulating envelopes are formed from the same insulation sheet so as to be inserted simultaneously into a plurality of notches of the stator. [Fig.6a] then illustrates the plurality of insulating envelopes 5 at the time of insertion into the notches of the stator and [Ligure 6b] illustrates the final shape of the insulating envelope 5 after cutting the assembly illustrated on [Ligure 6a].

In accordance with what has been described with reference to [fig.5], each insulating envelope has in an transverse plane an open profile, with an absence of internal sheet at the open end of the notch .

The insulating envelope 5 of [fig.6a] differs from the above in that it is obtained by a particular process, with a single insulating sheet which is folded to form the plurality of insulating envelopes brought to fit into the notches in the stator body. Such a configuration of the insulating sheet confers a technical advantage in that it accelerates the installation of all of the insulating envelopes 5 in all of the notches by a single manipulation.

The insulating envelope 5 comprises, conforming to what has been described above, a bottom sheet 56 configured to cooperate with the bottom wall of the notch, as well as a first radial sheet 58a and a second radial sheet 58b, forming respectively with the bottom sheet 56, the first sheet corner 57a and the second sheet corner 57b configured to cooperate with the first corner and the second corner of the notch.

The insulating envelope 5 does not have an internal sheet and therefore again has an open profile.

The plurality of insulating envelopes being originally formed by the same insulating sheet, so as to be arranged in the notches in a single operation, the assembly formed by this plurality of insulating envelopes comprises intermediate sheets 60 configured to connect two by two of the neighboring insulating envelopes 5, and more particularly to connect a first radial sheet 58a of a first insulating envelope and a second radial sheet 58b of a second insulating envelope close to the first insulating envelope. When the assembly is positioned on the stator body, these intermediate sheets are positioned opposite the interior faces of the teeth of the stator body, visible in FIGS. 1 and 2. It will then be understood that there is an alternating arrangement of the intermediate sheets 60 and open ends 32 of notches when the assembly is in position.

According to the invention, and as can be seen in [fig.6a], the fold zone between the intermediate sheets 60 and the radial sheets 58a, 58b is produced by means of an axial alignment of microperforations 52.

It is understood that once the plurality of insulation envelopes 5 of [fig.6a] inserted into the notches of the stator body, the inner faces of the stator teeth are covered by the intermediate sheets 60 of l insulating jacket 5.

The open profile allows the insertion of the conductive elements 41 in the notch 3 via the open end 32 from an inside diameter 9 to an outside diameter of the stator body 2, the presence of the insulator covering the flanges 10 protecting conductors from contact with these same edges, helping to maintain the integrity of the enamel of these same conductors.

The method of obtaining then comprises, in addition to the step of folding the insulating sheet and after its installation and the installation of the conductors in the notches of the stator body, a step of cutting out each intermediate sheet 60 forming in said assembly a connection between two insulating envelopes 5, so as to release the inner faces 9 of the teeth 8 formed between the notches.

This mechanical removal operation of the intermediate sheets 60 is carried out by tearing them thanks to microperforations 52. The tearing generates perforated edges 62, visible in [fig.6b]. More particularly, each insulating casing 5 has, in a transverse plane perpendicular to the axis of the stator, an open profile, with edges delimiting the opening of the profile which are perforated edges 62. It is understood that the perforated edges 62 are arranged on the side of the open ends 32 of the notches of the stator.

The invention thus achieves the goal it set for itself by improving the covering of the walls of the notches in the body of the stator by means of more angular folds of the insulation sheets by means of microperforations.

The invention cannot however be limited to the means and configurations exclusively described and illustrated, and also applies to all means or configurations, equivalent and to any combination of such means or configurations.

Claims (1)

Claims [Claim 1] Stator body for a rotary electrical machine comprising a series of notches (3) arranged around an axis of the stator (1), at least one notch (3) being lined with an insulating envelope (5) having at least one zone fold (53) to match the shape of the notch (3), characterized in that the insulating envelope (5) comprises microperforations (52) arranged linearly so as to define the at least one fold zone (53) of the insulating jacket (5). [Claim 2] Stator body for a rotary electrical machine according to the preceding claim, in which the microperforations (52) have a diameter of less than 0.7 mm. [Claim 3] Stator body for a rotary electrical machine according to one of the preceding claims, in which the insulating envelope (5) comprises perforations (54) formed outside the fold zones (53) and having a diameter greater than that of the microperforations ( 52). [Claim 4] Stator body for a rotary electrical machine according to one of the preceding claims, in which at least part of the microperforations (52) is arranged so as to form alignments parallel to the axial direction of the stator (1). [Claim 5] Stator body for a rotary electrical machine according to one of the preceding claims, in which at least part of the microperforations (52) is arranged so as to form alignments parallel to a radial direction of the stator (1). [Claim 6] Stator body for a rotary electrical machine according to one of the preceding claims, in which the insulating jacket (5) is made of a polyester or polymer type material. [Claim 7] Stator body for a rotary electrical machine according to one of the preceding claims, in which the notch (3) comprises a bottom wall (31) and an open end (32) facing the bottom wall (31), and the insulating jacket (5) is folded so as to have, in a transverse plane perpendicular to the axis of the stator, a closed profile, so that this insulating jacket partitions the open end (32) of the notch ( 3). [Claim 8] Stator body for a rotary electrical machine according to one of Claims 1 to 6, in which the insulating envelope (5) is folded so as to have, in a transverse plane perpendicular to the axis of the stator, an open profile, l 'insulating envelope including edges delimiting the opening of the profile which are perforated edges (62). [Claim 9] Method for obtaining a stator body for a rotary electric machine according to the preceding claim, during which an insulating sheet is folded so as to form an assembly comprising in one piece several insulating envelopes (5) capable of being housed respectively. in one of the notches in the stator body, the process for obtaining further comprising a step of cutting each intermediate sheet (60) forming in said assembly a connection between two insulating envelopes (5), said cutting step being carried out once the insulating envelopes in position in the notches so as to release the inner faces (9) of the teeth (8) formed between the notches. [Claim 10] Rotating electric machine comprising at least one stator (1), the stator body of which conforms to one of claims 1 to 8. 1/5