Electric machine for a motor vehicle

Abstract

The invention relates to an electric machine (1) for a motor vehicle, the electric machine comprising at least one casing (2), a transmission shaft (3) arranged at least partly inside the casing (2) and a rotor / stator assembly (4, 5) accommodated in the casing (2), the rotor (4) of which is secured to the transmission shaft (3), the electric machine (1) comprising at least one fastening means (15) for fastening the stator (5), the fastening means comprising a tapped hole (16) in the casing (2) and a fastening bolt (17) able to co-operate with the tapped hole (16), characterised in that the stator (5) comprises a stator body (8) surrounding the rotor (4) and an extension means (9) axially extending the stator body (8), the extension means (8) being in contact with the tapped hole (16) of the fastening means (15).

Description

Description Title of the invention: Electric machine for motor vehicle

[0001] The present invention relates to the field of motor vehicles, and more particularly to the electrical machines equipping these motor vehicles.

[0002] Electric or hybrid vehicles use electric machines, specifically electric machines with at least one stator and one rotor, which are often radial flux machines. In such machines, the rotor and stator are coaxial and arranged around each other, such that windings on the stator, or rotor respectively, and magnetic elements on the rotor, or stator respectively, generate a magnetic flux in a radial direction relative to an axis of rotation of the electric machine.

[0003] Radial flux electric machines are available in various power ratings. They are designed for integration into different types of vehicles according to the specific power requirements of those vehicles. The power output of an electric machine is primarily influenced by the axial dimensions of its two main components: the stator and the rotor.

[0004] Thus, to increase the power of an electrical machine, one can increase the axial dimensions of the stator and rotor. Conversely, to create a machine with lower power, one reduces their axial dimensions.

[0005] Currently, the manufacture of electrical machines of varying power ratings requires separate production lines. This is because the size of each component of the electrical machine must be adapted to the axial dimensions of the rotor and stator. Elements such as the housing, the drive shaft, the mounting hardware for the rotor / stator assembly, and other components are designed according to these dimensions. Consequently, a high-power electrical machine must be assembled on a different production line than one used for a low-power electrical machine, since the component parts of these machines are not interchangeable.

[0006] This separation of production lines results in a loss of time and energy, as it is necessary to maintain and operate several separate production lines. Furthermore, the differences between the parts require the manufacturing of unique components for each type of machine before assembly, which increases production costs and complexity.

[0007] The objective of the invention described in this document is therefore to overcome the disadvantages of the prior art by limiting the number of separate parts needed to make two electrical machines of different powers.

[0008] The present invention thus has as its main object an electric machine for motor vehicle comprising at least one casing, a transmission shaft disposed at least in part within the casing and a rotor / stator assembly housed in the casing and whose rotor is integral with the transmission shaft, the electric machine comprising at least one means for fixing the stator having a threaded barrel of the casing and a fixing screw adapted to cooperate with the threaded barrel, characterized in that the stator comprises a stator body surrounding the rotor and an extension means axially extending the stator body, said extension means being in contact with the threaded barrel of the fixing means.

[0009] The electric machine here is a radial flux electric machine, in which the rotor and stator are cylindrical elements mounted around a common axis formed by the axis of rotation of the transmission shaft. More specifically, it is an internal rotor electric machine, with the stator surrounding the rotor.

[0010] The electric machine according to the invention, which employs an extension means axially prolonging the stator body, is here referred to as a low-power electric machine. The term "low power" is intended to characterize the electric machine in contrast to a high-power electric machine. Thanks to the configuration of the electric machine according to the invention, the high-power electric machine is distinguished from the low-power electric machine by the fact that the stator body is in direct contact with the threaded barrel of the housing, without the interposition of an extension means, and by the fact that the rotor has a larger axial dimension than the rotor of the low-power electric machine.

[0011] It is thus understood that the small power electric machine, with a stator body and a rotor of axial dimensions smaller than those of the stator body and rotor of a large power electric machine, is sized to generate less power than that generated by the large power electric machine.

[0012] According to the invention, the presence of the extension means makes it possible to maintain a reference plane for the stator body that remains the same from a small-power electrical machine to a high-power electrical machine. It should be noted that this reference plane corresponds to the position of the stator body relative to an electronic control component of the rotor and stator of the electrical machine.

[0013] Indeed, the axial dimensions of parts other than the rotor / stator assembly are calibrated based on the axial dimensions of a rotor / stator assembly from a high-power electrical machine. Therefore, when a low-power rotor / stator assembly is used to create a low-power electrical machine, the stator body has a smaller axial dimension than the axial dimension of a stator body from a high-power electrical machine. The means of extension is then interposed between the stator body and the threaded shaft of the housing. The extension means ensures the fixing of the stator onto the threaded shaft, at the level of a first axial end of the stator, while maintaining the opposite axial end of the stator at the level of the previously mentioned reference plane.

[0014] This feature allows for the standardization of other parts. It is therefore important to understand that the casing, the drive shaft, the mounting hardware, and all the other components of the electric machine are common to both small and large-power electric machines. Consequently, during assembly on a production line, only the rotor / stator assembly needs to be changed to obtain either a small or a large-power electric machine.

[0015] Since the extension means extends axially from the stator body, and the stator body surrounds the rotor, and the stator body has approximately the same axial dimensions as the rotor, it follows that the extension means is axially offset from the rotor. In this way, the extension means has no magnetic effect on the rotor. Therefore, it is not necessary for the extension means to be made of a magnetic material.

[0016] According to an optional feature of the invention, the fixing screw comprises at least a head and a shank having a threaded end, the stator body being interposed between the head of the fixing means and the extension means.

[0017] The electric machine includes, in addition to the electronic control part, a motor output part, the electronic control part and the motor output part being arranged on either side of the casing.

[0018] The threaded shaft is machined into a closing wall of the housing on the motor output side. The screw head is located on the side of the electronic control unit. The stator / rotor assembly is thus mounted in the housing through an opening opposite the closing wall, until the extension means abuts against the threaded shafts. The fixing screw is then tightened, and the electronic control unit can be attached to the housing to position it close to the stator body and the reference plane formed by the axial end of the stator facing away from the extension means.

[0019] According to an optional feature of the invention, the shank of the fixing screw passes through the stator body and the extension means, the threaded end being housed in the tapped barrel.

[0020] The threaded barrel is arranged so that, when the threaded end is housed in the threaded barrel, the shank of the fixing screw extends in a direction parallel to the axis of rotation of the rotor.

[0021] It is therefore necessary to understand that, in this direction parallel to the axis of rotation of the transmission shaft going from the head of the fixing screw to its threaded end, the shank of the fixing screw passes through the stator body and then the extension means, the fixing screw being dimensioned so that, when the screw head is in contact with the stator body, the threaded end protrudes from the extension means in order to cooperate with the threaded barrel.

[0022] According to an optional feature of the invention, the extension means is removable relative to the stator body.

[0023] In other words, in this embodiment, the extension means takes the form of a spacer, manufactured separately from the stator body and then attached to it. The extension means is an added component intended to be interposed between the stator body and the threaded shaft for securing the stator body. This arrangement implies that the stator body has dimensions typical of a low-power electrical machine, notably the same axial dimensions as the rotor. The extension means allows for a local increase in the stator's axial dimension, enabling the use of the same fastening methods as when the stator body is manufactured with dimensions typical of a high-power electrical machine.

[0024] By adding the extension means, the stator body sized for a low power rotor / stator assembly also becomes compatible with an electrical machine designed for a high power rotor / stator assembly.

[0025] According to an optional feature of the invention, the extension means is formed of a different material from that forming the stator body.

[0026] The extension means is axially offset from the rotor, resulting in little or no electromagnetic interaction with it. Therefore, magnetic properties are not essential for the extension means. Consequently, the extension means can be made of a different material than the stator body, for example, a non-magnetic material. This characteristic allows for cost savings by using a less expensive material than that used for the stator body.

[0027] According to an optional feature of the invention, the extension means and the stator body form a single unit.

[0028] When the extension means and the stator body form a single unit, they are generally made from the same material, the extension means exhibiting a magnetic effect similar to that of the stator body. In this configuration, where the extension means and the stator body form a single unit, the stator as a whole can be considered a stator body, with an end portion of the stator body facing the rotor or not. depending on the type of electrical machine being assembled. In other words, the same stator body can be used in a high-power machine by fitting a rotor the same size as the stator body, and in a low-power machine by fitting a rotor with a smaller axial dimension than the stator body. In the first case, the stator body can be considered as having no means of extension and the entire stator body is functional, while in the second case, the end portion of the stator body that is axially offset from the rotor serves no other purpose than to ensure contact with the mounting bushings and must therefore be considered as a means of extension within the meaning of the invention. This simplifies the assembly since the only part of the rotor / stator assembly that changes between a high-power and a low-power electrical machine is the rotor.

[0029] According to an optional feature of the invention, the extension means is annular in shape and includes at least one orifice intended to cooperate with at least one fastening means.

[0030] The annular shape of the extension means allows it to conform to the cylindrical shape of the stator body, thus extending the stator body axially. Thanks to this shape, the extension means therefore surrounds the transmission shaft.

[0031] The orifice is an opening that passes through the extension means in a direction parallel to the axis of rotation of the transmission shaft. This orifice allows the fixing screw of the fixing means to pass through the extension means.

[0032] The stator body also includes at least one orifice through said stator body in a direction parallel to the axis of rotation of the transmission shaft and used to pass the fixing screw through the stator body.

[0033] The extension means is then positioned relative to the stator body so that the through-holes are coaxial. The extension means and the stator body are thus held in place within the housing by the fixing screw.

[0034] To ensure that the screw passes through each of the consecutive orifices, the orifice diameter of the extension means can be slightly larger than the orifice diameter of the stator body.

[0035] According to an optional feature of the invention, the stator comprises at least one radial boss, said radial boss comprising at least one orifice.

[0036] It is important to understand that the radial boss locally and radially increases the stator's dimensions, that is, in a radial direction perpendicular to the axis of rotation of the transmission shaft. This increase in thickness allows the mounting hardware and corresponding opening to be placed around the stator's periphery without reducing the amount of stator material contributing to field formation. Electromagnetic. The radial boss extends from one axial end of the stator to the other, so that it is in contact with the screw head on one side and with the threaded shaft on the other. Thus, the radial boss is present on both the stator body and the extension means.

[0037] The radial boss therefore includes an opening, which allows the fixing screw to pass through the radial boss of the stator in order to hold the stator and therefore the rotor / stator assembly in place in the housing.

[0038] The stator may include a plurality of radial bosses, and the electrical machine may include a plurality of fastening means. In this case, there may be one radial boss for each fastening means, such that the screw of each fastening means passes through the hole in each radial boss, thus securely holding the stator / rotor assembly in the housing. When there are a plurality of radial bosses, they may, for example, be equidistant from one another and arranged at regular angles to surround the stator. In this way, when the fastening screws pass through their holes, the rotor / stator assembly is securely fastened to the housing.

[0039] According to an optional feature of the invention, the axial dimension of the extension means is at least 5%, and preferably at least 20%, of that of the stator body.

[0040] This axial dimensioning of the extension means is designed so that the stator, formed by the stator body and extension means assembly, has the same size as a stator body of a high-power electrical machine. Thus, the stator according to the invention can be placed in the housing of a high-power electrical machine, and the components of these high-power machines can be used in the assembly of a low-power electrical machine. In other words, the axial dimension of the extension means is determined to compensate for the missing axial dimension of the stator body of the low-power electrical machine in order to achieve the axial dimension of the stator body of the high-power electrical machine.

[0041] It should be noted that this axial dimension value is such that the means of extension is distinguished from a simple stiffening rib that would protrude axially from the stator body.

[0042] The invention also relates to an assembly method enabling, in particular, the manufacture of an electrical machine as previously mentioned. More specifically, according to the invention, an assembly method for an electrical machine may comprise at least the following steps: 1. Identification of a reference for a first type of electrical machine or a reference for a second type of electrical machine, 2. Assembly of an electrical machine according to the indicated reference, with:

[0043] - if the reference corresponds to the first type of electrical machine, an assembly of an electrical machine as previously mentioned,

[0044] - if the reference corresponds to the second type of electric machine, assembly of an electric machine in which the casing and the transmission shaft are similar to those of the electric machine as previously mentioned and comprising a stator body pressed directly against the threaded barrels of the casing, as well as a rotor of the same axial dimension as this stator body.

[0045] This process allows for the production of two types of machines on the same production line. Indeed, all the parts, with the exception of the rotor / stator assembly, are identical in both small and large power electric machines. Therefore, the assembly of the electric machine is essentially the same. The only difference lies in the positioning of the rotor / stator assembly, which varies depending on whether it is a small or large power electric machine.

[0046] Thus, for a small power electrical machine, a stator consisting of a rotor body and an extension means is installed, as described in the description, and a rotor with the same axial dimensioning as the stator body is installed.

[0047] If it is a high-power machine, a stator is installed which consists only of a stator body which has the same axial dimensions as the stator of the low-power machine and a rotor is installed which has the same axial dimensions as the stator body.

[0048] This process allows for significant savings in time and energy, since the fastening methods remain the same for both types of electrical machines. Therefore, more electrical machines can be produced more quickly, and production can be easily changed if a switch from a high-power to a low-power electrical machine is required.

[0049] Other features, details and advantages of the invention will become clearer upon reading the following description on the one hand, and the illustrative and non-limiting examples of embodiments given with reference to the accompanying drawings on the other hand, in which:

[0050] [Fig.1] is a cross-section of a small power electrical machine according to a first embodiment of the invention.

[0051] [Fig.2] is a perspective view of a low-power rotor / stator assembly of the electric machine according to the first embodiment.

[0052] [Fig.3] is a cross-section of a small power electrical machine according to a second embodiment of the invention.

[0053] [Fig.4] is a perspective view of a low-power rotor / stator assembly of the electric machine according to the second embodiment.

[0054] [Fig-5] is a cross-section of a high-power electrical machine.

[0055] The features and variants of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of the features described below, isolated from the other described features, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0056] In the figures, elements common to several figures retain the same reference.

[0057] Figure 1 is a cross-section of a small-power electrical machine according to a first embodiment of the invention. The small-power electrical machine 1 includes, in particular, a housing 2 designed to accommodate either a high-power rotor / stator assembly or a low-power rotor / stator assembly, a drive shaft 3 that can cooperate with either a high-power rotor / stator assembly or a low-power rotor / stator assembly, and it includes a low-power rotor / stator assembly 4, 5. In addition, the electrical machine 1 includes an electronic control section 6 and a motor output section 7.

[0058] More specifically, the casing 2 is an enclosure that surrounds certain components of the small power electric machine 1. The small power rotor / stator assembly 4,5 is thus housed in this casing 2, and part of the transmission shaft 3 is also located in the casing 2. The casing 2 includes a closing wall 60 which extends perpendicularly to an axis of rotation A of the transmission shaft, and opposite the motor output part 7. This closing wall 60 is traversed only by the transmission shaft 3.

[0059] The stator 5 is a stationary part of the small power electric machine 1. It may include conductive elements which, when supplied with electricity, generate a magnetic field, or conversely, when subjected to a magnetic field, generate an electric current at the machine's output. These conductive elements may, in particular, be arranged axially in slots formed within the stator, and the winding formed by all these interconnected conductive elements presents coils 25 at the axial ends of the stator, schematically represented in the figures.

[0060] The electronic control unit 6 is specifically configured to supply electrical current to the conductive elements of the stator 5, excite the wound rotor 4, and recover the electrical current. The electronic control unit 6 includes a plurality of electronic components for controlling the electrical connection. with the conductive elements. Due to this electrical connection, it is necessary to ensure that the position of the electronic control part 6 relative to the stator 5 and the rotor 4 is in accordance with the desired theoretical position.

[0061] The rotor 4 is a component of the electric machine rotating around the axis of rotation A. It can, for example, consist of coils wound on a pole reacting to the magnetic field produced within the stator 5, which has the effect, by driving a rotating magnetic field, of generating a rotational movement around this axis of rotation A.

[0062] The drive shaft 3 is connected to the rotor 4; thus, when the rotor 4 rotates, the drive shaft also rotates around the axis of rotation A. The drive shaft 3 then transmits the mechanical energy of the rotational movement to the motor output part 7.

[0063] The stator 5 and the rotor 4 both have a cylindrical shape surrounding the axis of rotation A. In the illustrated example of a radial flux internal rotor motor, the stator 5 surrounds the rotor 4, which itself surrounds the transmission shaft 3. The magnetic field within the stator 5 passes radially between the stator 5 and the rotor 4.

[0064] The stator 5 comprises, in addition to the winding, a stator body 8 and an extension means 9. The extension means 9 extends the stator body 8 in an axial direction D. This axial direction D is parallel to the axis of rotation A. The stator body 8 and the extension means 9 are both cylindrical parts, with a common axis, here coinciding with the axis of rotation A of the transmission shaft.

[0065] The stator body 8 comprises a first axial end 10 and a second axial end 11. These ends therefore correspond to ends of the cylinder formed by the stator body 8 in the axial direction D.

[0066] The extension means 9 includes a first axial edge 12 and a second axial edge 13. These edges correspond to the ends of the cylinder formed by the extension means in the axial direction D.

[0067] The extension means axially extends the stator body such that the second axial end 11 of the stator body 8 is in contact with the first axial edge 12 of the extension means 9. In this way, the stator 5 as a whole is axially delimited on one side by the first axial end 10 of the stator body 8 and on the other side by the second axial edge 13 of the extension means 9. In other words, the stator 5 extends axially between this first axial end 10 and this second axial edge 13.

[0068] The rotor 4 comprises a first axial termination 14A and a second axial termination 14B. The arrangement of the extension means 9 within the stator 5 results in an axial misalignment of the rotor 4 with respect to the stator 5. The rotor 4 is therefore not axially centered with respect to the stator 5, but rather axially coincident. with the stator body 8. In other words, the first axial termination 14A of the rotor 4 is positioned at the same axial level as the first axial end 10 of the stator body 8, and the second axial termination 14B of the rotor 4 is positioned at the same axial level as the second axial end 11 of the stator body 8. The stator body 8 thus surrounds the rotor 4, while the extension means 9 is axially offset with respect to the rotor 4 and therefore does not surround it.

[0069] A radial magnetic field is formed between the stator body 8 and the rotor 4, facing each other along this radial direction. The extension means 9, however, since it is axially offset from the rotor 4, does not need to possess magnetic strength. As will be described below, its sole function is to secure the stator to threaded shafts, which are used regardless of the size of the electrical machine. The extension means can therefore be made of a different material than the stator body 8, for example, an inexpensive plastic material with no electromagnetic properties.

[0070] As mentioned, the small power electric machine 1 also includes at least one means 15 for securing the stator 5. This means 15 includes, in particular, a threaded barrel 16 formed in the closing wall 60 and a fixing screw 17. When the stator 5 is disposed in the housing 2, the means 15 is configured to be able to press the extension means 9 of the stator 5 against the threaded barrel 16. More precisely, the second axial edge 13 of the extension means 9 is the part of the stator 5 that is in contact with said threaded barrel 16.

[0071] The fixing screw 17 comprises a shank 18 and a head 19, the shank having a threaded end 20. The threaded end 20 is designed to cooperate with the threaded barrel 16 of the housing 2. The shank 18 passes through the stator body 8 and the extension means 9. The stator body 8 and the extension means 9 have through holes for this purpose, which are aligned when the extension means 9 is against the stator body 8. These through holes, when aligned, form an opening 24 visible in [Fig. 2]. This opening 24 is intended to be traversed by the shank 18. Thus, the shank 18 passes through the stator body 8 from its first axial end 10 to its second axial end 11, and then through the extension means 9 from its first axial edge 12 to its second axial edge 13, following the axial direction D.

[0072] It should be noted that in this embodiment the stator comprises several orifices 24, each of the orifices 24 being formed by a through orifice of the stator body and a through orifice of the extension means.

[0073] When the stator is housed within the casing, it is inserted through an opening opposite the closing wall 60 carrying the threaded barrels 16, until the extension means is in contact with these threaded barrels 16. The fixing screws 17 are then inserted into the corresponding holes 24, so that the shank 18 of the fixing screw 17 successively passes through the stator body 8 and the extension means 9 so that its threaded end 20 cooperates with the threaded barrel 16. The head 19 of the screw is then positioned in contact with the first axial end 10 of the stator body 8 to participate in the clamping of the stator 5 against the threaded barrels 16.

[0074] The faces of the threaded barrels 16, against which the extension means rests, form a reference positioning surface and ensuring that the stator is firmly pressed against these threaded barrels ensures that the stator is correctly positioned in the housing, in particular with respect to the electronic control part 6.

[0075] It is thus understood that thanks to the extension means 9, which participates in forming the stator, the low power rotor / stator assembly 4,5 can be correctly positioned in a housing 2 which is designed to accommodate a stator body and a rotor of a high power rotor / stator assembly which would therefore have an axial dimension equivalent to the axial dimension of the complete stator 5 of this embodiment.

[0076] In order for the extension means 9 to allow the low power rotor / stator assembly 4.5 to be positioned in the housing 2 designed for a high power rotor / stator assembly, the axial dimensioning of this extension means 9 must correspond to the difference in axial dimensioning between a low power stator body 8 and a high power stator body 8.

[0077] It should be noted, particularly as can be seen in the figures, that the extension means 9 according to the invention should be understood as an excess of material whose function is to ensure the positioning of a low-power stator body 8, by passing through an orifice intended to receive a fixing screw, and it cannot be confused for this purpose with a simple stiffening rib that would extend axially from the stator body. More specifically, the axial dimension of the extension means 9 is at least 5% of the axial dimension of the low-power stator body 8. Preferably, the axial dimension of the stator body of the extension means is at least 20% of the axial dimension of the low-power stator body 8.

[0078] In this first embodiment illustrated in [Fig.1], the extension means 9 is removable from the stator 5. More precisely, the extension means 9 is made independently of the stator body 8 and can be separated from the latter by removing the fixing screw 17. In other words, the stator 5 is formed by two distinct parts, namely the stator body 8 and the extension means 9.

[0079] Figure 2 is a perspective view of the low-power rotor / stator assembly. 4.5 according to the embodiment of [Fig.1].

[0080] This figure allows for a clearer observation of the fact that the rotor 4 and the stator 5 are cylinders, and helps to better understand that the stator 5 surrounds the rotor 4, which surround the axis of rotation A. This figure also makes visible the shape of the extension means 9 and the fact that the stator 5 includes radial bosses 23 within which are formed the holes for the passage of the fixing screws.

[0081] The radial bosses 23 are local increases in the radial dimension of the stator 5, the radial dimension being measured perpendicular to the axis of rotation A. The radial bosses 23 are configured to locally increase the radial dimension of the stator along its entire axial dimension. The radial bosses 23 extend parallel to the axis of rotation A continuously from the first axial end 10 of the stator body 8 to the second axial edge 13 of the extension means 9. The radial bosses 23 therefore extend continuously over both the stator body 8 and the extension means 9.

[0082] In this embodiment, the stator 5 comprises four radial bosses 23 arranged at regular intervals around the circumference of the stator 5. Each of the radial bosses 23 comprises an orifice 24 as previously described. Each of these orifices 24 extends within one of the radial bosses 23, parallel to the axis of rotation A.

[0083] Since composed of through orifices in the stator body and through orifices in the extension means, the orifices 24 can be considered as passing through the whole of the stator 5, and therefore pass through said stator 5 from the first axial end 10 of the stator body 8 to the second axial edge 13 of the extension means 9. 9.

[0084] As mentioned previously, these orifices 24 are arranged to house respectively the rod 18 of one of the fixing screws 17 in order to allow the positioning of the low power rotor / stator assembly 4.5 in the housing 2.

[0085] The extension means 9 includes an annular band 50 surrounding the rotor 4. This annular band 50 serves as a support for the radial bosses 23 of the extension means 9. The extension means 9 thus has an annular shape enabling it to follow the cylindrical shape of the stator body 8 and thus axially extending the stator body 8.

[0086] We will now describe a second embodiment, with reference to figures 3 and 4 which respectively illustrate in section and perspective a small power electrical machine according to this second embodiment of the invention.

[0087] As previously described, the small-power electric machine 1 comprises a housing 2 designed to accommodate either a high-power rotor / stator assembly or a low-power rotor / stator assembly, as well as a drive shaft 3 common to both assemblies. Furthermore, the electric machine 1 includes an electronic control unit 6 and a motor output unit 7, along with a mounting means. The housing 2, the drive shaft 3, the electronic control unit 6, the motor output unit 7, and the mounting means are similar to those of the first embodiment, the description of which is given in the description of [Fig.1] in relation to these elements therefore applies identically to this embodiment.

[0088] One of the differences of this second embodiment with the first embodiment lies in the small power stator / rotor assembly 4.5 and more particularly in the extension means 9.

[0089] In this second embodiment, the extension means 9 forms a single unit with the stator body 8. A single unit is understood to mean that the extension means 9 cannot be separated from the stator body without damaging one or both. Here, the single unit is made of a single material so that the extension means 9 has the same magnetic properties as the stator body 8.

[0090] The rotor 4, for its part, remains similar in terms of dimensions and materials to that of the first embodiment when it comes to implementing a small power electrical machine.

[0091] The fact that the extension means can contribute to the formation of a magnetic field makes it possible for the stator 5 of this second embodiment to also be used in high-power rotor / stator assemblies, since it is possible to use a high-power rotor with an axial dimension identical to that of the monobloc assembly forming the stator. Thus, to convert the low-power electric machine 1 of this second embodiment into a high-power electric machine, it is sufficient to replace the rotor 4 with a rotor having an axial dimension equal to that of the stator 5.

[0092] Apart from this difference, the cylindrical shape of the low-power rotor / stator assembly 4.5 is similar to that of the first embodiment. Furthermore, the presence of radial bosses 23 and openings 24 allowing attachment to the housing 2 by means of the housing 2's fastening means 15 is also identical to that of the first embodiment. These features are particularly visible in [Fig. 4].

[0093] It should also be noted that it is entirely possible to have an extension means which is removable in accordance with the first embodiment, but made of the same material as the stator body.

[0094] The [Fig.5] is a cross-section of a high-power electrical machine 26 and aims to illustrate the advantage of the means of extension, whether it is carried out according to the first or second embodiment.

[0095] The high-power electric machine 26 includes, in particular, a housing 2 designed to accommodate a high-power rotor / stator assembly, a transmission shaft 3, and a high-power rotor / stator assembly 27, 28. Furthermore, the electric machine 1 includes an electronic control unit 6 and a motor output unit 7, as well as a mounting means 15. The housing 2, the transmission shaft 3, the electronic control part 6, the motor output part 7 and the fastening means are similar to those of the first and second embodiments; the description given in that of [Fig.1] concerning these elements applies here.

[0096] The difference with the small-power electrical machines 4,5 lies in the fact that the high-power electrical machine 26 comprises a high-power rotor / stator assembly 27, 28. This high-power rotor / stator assembly 27, 28 includes a stator 28 and a rotor 27, with the rotor 27 having a larger axial dimension than the axial dimension of the rotors intended for the small-power electrical machines. Advantageously, the stator 28, consisting solely of a stator body and a winding, here with a baffle 25, has the same axial dimension as the axial dimension of the stator, including the extension means 9, of the small-power electrical machine. Thus, the same housing can be reused regardless of whether the rotor / stator assembly to be inserted into the housing is a high-power or low-power rotor / stator assembly.

[0097] We will now describe an assembly process for an electrical machine as just mentioned, with in particular a first example of an assembly process when a small power machine 1 according to the first embodiment is envisaged and a second example of an assembly process when a small power machine 1 according to the second embodiment is envisaged.

[0098] In both cases, the assembly process allows, on the same production line and without the need to stop the line at each change of reference of machine to be assembled, the assembly of a small power electrical machine 1 or the assembly of a large power electrical machine.

[0099] In both cases, the assembly process includes an identification step, during which an operator or a machine identifies on the production line a reference that allows differentiation between whether one wants to assemble a small power electrical machine 1 or a large power electrical machine 26.

[0100] In each case, following this identification step, the assembly process includes an assembly step. In this step, if a small power electrical machine 1 has been identified, the set of parts common to small and large power machines is assembled and a small power rotor / stator assembly 4,5 is installed. If a large power electrical machine 26 is identified, the set of parts common to small and large power machines is assembled and a large power rotor / stator assembly 27,28 is installed as described in [Fig.5].

[0101] The first example of the process differs from the second example of the process in that, during the assembly step, the operator positions the means against the threaded barrels The extension (9) is used before positioning the stator body and tightening the assembly against the threaded barrels using the fixing screws. Advantageously, the operator can first pass a fixing screw through the openings formed in the extension and the stator body to secure them during insertion into the housing. In the second method example, the stator inserted into the housing can be the same regardless of the electrical machine identified in the identification step; only the rotor differs depending on whether a small-power electrical machine (1) or a large-power electrical machine (26) has been identified.

[0102] As described above, the present invention achieves its intended purpose by providing an electric motor for motor vehicles comprising a housing, a drive shaft, and a rotor / stator assembly. The stator includes an extension mechanism to increase the axial dimension of the stator body. This design allows the use of standardized components to manufacture electric motors of varying power ratings, thus simplifying and simplifying their production process.

[0103] The present invention is not limited to the means and configurations described and illustrated herein, and also extends to any equivalent means and configuration as well as any technically operative combination of such means.

Claims

Demands

1. Electric machine (1) for motor vehicle comprising at least one housing (2), a transmission shaft (3) disposed at least in part within the housing (2) and a rotor / stator assembly (4,5) housed in the housing (2) and of which the rotor (4) is integral with the transmission shaft (3), the electric machine (1) comprising at least one fixing means (15) for the stator (5) having a threaded barrel (16) of the housing (2) and a fixing screw (17) adapted to cooperate with the threaded barrel (16), characterized in that the stator (5) comprises a stator body (8) surrounding the rotor (4) and an extension means (9) axially extending the stator body (8), said extension means (8) being in contact with the threaded barrel (16) of the fixing means (15).

2. Electric machine (1) for motor vehicle according to claim 1, wherein the fixing screw (17) comprises at least one head (19) and a shaft (18) having a threaded end (20), the stator body (8) being interposed between the head (19) of the fixing means (15) and the extension means (8).

3. Electric machine (1) for motor vehicle according to claim 2, wherein the shank (18) of the fixing screw (17) passes through the stator body (8) and the extension means (9), the threaded end (20) being housed in the tapped barrel (16).

4. Electric machine (1) for motor vehicle according to any one of claims 1 to 3, wherein the extension means (9) is removable from the stator body (8).

5. Electric machine (1) for motor vehicle according to any one of claims 1 to 4, wherein the extension means (9) is formed of a material different from that forming the stator body (8).

6. Electric machine (1) for motor vehicle according to any one of claims 1 to 3, wherein the extension means (9) and the stator body (8) form a single unit.

7. An electric machine (1) for a motor vehicle according to any one of claims 1 to 6, wherein the extension means (9) is annular in shape and comprises at least one orifice (24) for cooperating with at least one fastening means

8. Electric machine (1) for motor vehicle according to claim 7, wherein the stator (5) comprises at least one radial boss (23), said radial boss (24) comprising F at least one orifice (24).

9. Electric machine (1) for motor vehicle according to any one of claims 1 to 8, wherein the axial dimension of the extension means (9) is at least 5%, and preferably at least 20%, of that of the stator body (8).

10. Method for assembling (30,40) an electrical machine comprising at least the following steps: - identification (32,42) of a reference of a first type of electrical machine (1) or of a reference of a second type of electrical machine (26), - assembly (34, 44) of an electrical machine according to the reference indicated: if the reference corresponds to the first type of electrical machine (1), assembly of an electrical machine according to any one of claims 1 to 9, if the reference corresponds to the second type of electrical machine (26), assembly of an electrical machine in which the casing and the drive shaft are similar to those of the electrical machine according to any one of claims 1 to 9, and comprising a stator body pressed directly against the threaded barrels of the casing, and a rotor of the same axial dimension as this stator body.

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