ELECTRIC MACHINE CASING

Abstract

The invention relates to a housing (10) for an electric motor vehicle, comprising at least: - a first housing element (12), configured to allow the housing (10) to be attached to a component (11) of said vehicle, and comprising at least one tubular portion (16) with axis A adapted to internally receive a stator (18) of said electric motor, - at least one second, substantially tubular, housing element (22), mounted externally to said tubular portion (16), said at least one second housing element (22) defining with said first housing element (12) at least one circulation chamber (24) for a cooling fluid. Figure for the abstract: Figure 7

Description

Title of the invention: ELECTRICAL MACHINE CASING Technical field of the invention

[0001] The invention relates to an electrical machine housing. Technical background

[0002] A high-power electrical machine, such as an electric machine intended to equip a motor vehicle, requires a cooling system for its operation. This cooling system is generally a liquid cooling system comprising a circulating chamber of a cooling fluid that surrounds the stator of the electrical machine in such a way as to allow maximum absorption of heat by said cooling fluid.

[0003] The stator is housed in a casing of the electric machine. The casing thus performs two main mechanical fastening functions: attaching the electric machine to a transmission casing of the vehicle or a vehicle body structure, and retaining the stator within the electric machine. Furthermore, the casing performs a hydraulic function, as the circulation chamber is located inside the casing.

[0004] The casing can be monobloc and in this case the circulation chamber is arranged in the thickness of the casing walls.

[0005] The casing can be in two parts, and in this case the circulation chamber is hydraulically delimited between the two parts. Since the stator is housed in the casing of the electric machine, it is therefore necessarily housed in one of these parts.

[0006] To facilitate assembly, it is desirable to decouple the functions performed by these two housings by grouping the majority of the main mechanical fastening functions on one of the two housing elements, and limiting the functions performed by the other housing. Summary of the invention

[0007] The invention satisfies this need by proposing an electric machine housing whose main mechanical fixing functions and hydraulic function are decoupled.

[0008] To this end, the invention proposes an electric motor vehicle machine housing, comprising at least:

[0009] - a first housing element, configured to allow the housing to be fixed to an element of said vehicle, comprising at least one tubular part with axis A suitable for internally receiving a stator of said electrical machine,

[0010] - at least one second substantially tubular housing element, mounted external to said tubular part,

[0011] said at least a second casing element delimiting with said first casing element at least one cooling fluid circulation chamber.

[0012] The arrangement of the circulation chamber between the first and second housing elements allows the majority of the main mechanical fastening functions to be grouped on the first housing element, and the hydraulic function on the arrangement of the second housing element around the first. Consequently, this design simplifies the assembly of the housing by grouping most of the mechanical fastening functions on the first housing element and minimizing those assigned to the second housing element.

[0013] This configuration also allows the high mechanical resistance requirements to be reserved mainly for the first housing element since the second housing element provides few or no mechanical fixing functions other than its own fixing, which makes it possible to consider a design of the second housing element in a material with lower mechanical resistance characteristics.

[0014] Furthermore, according to this design, any intervention or maintenance operation carried out on the circulation chamber does not affect the fixing of the casing or the components of the electrical machine.

[0015] According to various additional features of the invention, which may be taken together or separately and which constitute so many embodiments of the invention:

[0016] - said first housing element includes a fixing wall allowing the fixing from the crankcase to the component of said vehicle,

[0017] - said at least a second housing element is fixed to the first housing element,

[0018] - the fixing wall extends transversely with respect to the axis A of the part tubular,

[0019] - the fixing wall is arranged at a first axial end of said part tubular,

[0020] - the mounting wall has a first housing for a first bearing of a rotor of the electrical machine,

[0021] - a first side of the fixing wall is suitable for being fixed to the component of said vehicle,

[0022] - the first side of the fixing wall is shaped into a flat wall suitable for cooperate with a complementary flat wall of the vehicle component,

[0023] - a first end of one of at least a second housing element is fixed to a second, opposite side of the mounting wall,

[0024] - a second end of at least one second housing element includes an annular transverse wall,

[0025] - said annular transverse wall is centered on a second axial end of said tubular part,

[0026] - the tubular part is closed at its second end by a transverse partition,

[0027] - said transverse partition includes a second housing for a second rotor bearing of the electric machine,

[0028] - the annular transverse wall comprises a first axial segment by which it is centered on the second axial end of said tubular part,

[0029] - the annular transverse wall comprises a second axial section extending axially beyond the second axial end of said tubular part,

[0030] - the transverse partition is attached to the second axial section,

[0031] - the transverse partition and the second axial section are in continuous material,

[0032] - the transverse partition is arranged at a distance from the second end of the part tubular,

[0033] - the transverse partition extends inside the tubular part and delimits with the first axial section of the annular transverse wall, an annular groove which receives the second axial end of said tubular part,

[0034] - the transverse partition contributes to the fixing of the electrical machine,

[0035] - a first sealing system is interposed between said fixing wall and the first axial end of said tubular part,

[0036] - a second sealing system is interposed between said transverse wall annular and the second axial end of said tubular part,

[0037] - one of the first and second sealing systems comprises an annular seal with one has radial compression and the other has an axial compression annular seal.

[0038] - the first sealing system comprises a radial compression annular seal interposed radially between a shoulder span extending from the second side of the mounting wall and the first end of the second housing element,

[0039] - the first sealing system comprises an axial compression annular seal interposed axially between the second side of the fixing wall and the first axial end of the second housing element,

[0040] - the second sealing system comprises: • an annular collar of the annular part, arranged near the second axial end of said tubular part, and which extends radially to the second housing element, • an axial compression seal, interposed axially between said collar and the annular transverse wall of the second housing element,

[0041] - at least one circulation chamber extends axially between said wall of fastening and said annular collar,

[0042] - the second sealing system comprises a radially interposed annular seal between the first section of said annular transverse wall and the second axial end of said tubular part,

[0043] - the first axial section of the annular transverse wall extends along a guide short, following 8 to 12% of the length of a section of the second element surrounding the tubular part,

[0044] - the second housing element has a housing for a module of motor management electronics for electric machines. Brief description of the figures

[0045] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent in the course of the detailed explanatory description which follows, of at least one embodiment of the invention, given by way of purely illustrative and non-limiting example, with reference to the accompanying schematic drawings, among which:

[0046] - Fig. 1 is a first perspective view of a first element of a housing of an electric machine according to the invention housing a rotor and a stator of an electric machine;

[0047] - [Fig.2] is a second perspective view of the first housing element;

[0048] - [Fig. 3] is a perspective view of an electrical machine according to a first method of implementing the invention;

[0049] - [Fig. 4] is a cross-sectional view of the elements of the electric machine housing according to the first embodiment of the invention;

[0050] - [Fig. 5] is a cross-sectional view of the electrical machine according to the first mode of realization of the invention;

[0051] - [Fig. 6] is a perspective view of the casing elements of a machine electric according to a second embodiment of the invention;

[0052] - [Fig.7] is a cross-sectional view of the elements of the electric machine housing according the second embodiment of the invention;

[0053] - [Fig.8] is a cross-sectional view of the electrical machine according to the second mode of realization of the invention;

[0054] - [Fig.9] is a cross-sectional view of the elements of the electric machine housing according a third embodiment of the invention. Detailed description of the invention

[0055] Figures 4, 7, and 9 show a housing 10 for an electric motor vehicle machine manufactured according to the invention. The housing 10 and its components will be described with reference to the directions of the trihedral angle "A", "B", "C", where "A" denotes the direction axial, "B" designates a first transverse direction and "C" designates a second transverse direction.

[0056] According to the invention, the housing 10 of an electric motor vehicle machine comprises at least a first housing element 12 which is configured to allow the housing 10 to be fixed to a component of said vehicle. The vehicle component is, for example, a gearbox 11, as shown in particular in [Fig. 9].

[0057] As illustrated in Figures 5 and 8, which represent an electrical machine 14 equipped with such a housing 10, the first housing element 12 comprises at least one tubular part 16 with axis A which is suitable for internally receiving a stator 18 of the electrical machine 14. As illustrated in Figures 4 and 7, the stator is received in a housing 17 of the tubular part 16 which is formed as a bore of the tubular part 16.

[0058] The stator 18 internally receives a rotor 20 of the electric machine, which is mounted to rotate in the casing 10, as will be seen in more detail later in this description.

[0059] According to the invention, the housing 10 of an electric motor vehicle machine comprises at least a second substantially tubular housing element 22, which is mounted externally on said tubular part 16 of the first element 12.

[0060] Advantageously, this second housing element 22, together with the first housing element 12, and in particular with its tubular portion 16, defines at least one cooling fluid circulation chamber 24. The cooling fluid is a heat transfer fluid capable of absorbing the heat generated by the operation of the electric machine. It is introduced into the circulation chamber 24, absorbs the heat as it passes through it, and is then discharged from the circulation chamber 24 into a cooling circuit of the associated vehicle (not shown).

[0061] In the figures, a single second housing element 22 is shown surrounding the tubular part 16 of the first housing element 12. The second housing element 22 thus delimits with the tubular part 16 a single chamber 24 for the circulation of a cooling fluid.

[0062] It will be understood that this configuration is not limiting to the invention, and that the tubular portion 16 of the first housing element 12 can be surrounded by several second housing elements 22 separated from each other, which together would define as many circulation chambers for a cooling fluid. In this case, the circulation chambers could be independent or interconnected to allow the passage of the cooling flow from one chamber to another.

[0063] In the figures, a tubular part 16 substantially smooth externally is also shown around which is mounted a second housing element 22 substantially smooth internally.

[0064] It will also be understood that this configuration is not limiting of the invention, and that either of the housing elements 12, 22 may have protruding shapes inside the circulation chamber 24 in order to increase heat exchange within this circulation chamber 24. For example, these protruding elements could take the form of fins, or a helix shape wound around the tubular part 16 of the first housing element 12 or inside the second housing element 22 opposite the tubular part 16 in order to promote heat exchange between the tubular part 16 and the cooling fluid, in particular by increasing the heat exchange surfaces and allowing mixing of the cooling fluid.

[0065] The particularly advantageous feature of this design is that the arrangement of the circulation chamber 24 between the first housing element 12 and the second housing element 22 allows for the separation of the mechanical fastening functions from the hydraulic functions. Indeed, all the mechanical fastening functions are grouped on the first housing element 12 alone, whether it be its attachment to a vehicle component or the retention of the stator 18. The hydraulic function associated with the circulation of the cooling fluid is specifically dedicated to the mounting of the second housing element 22 around the first housing element 12.

[0066] This makes it possible, during maintenance operations, to avoid a complete disassembly of the electric machine 14 when only the replacement of the second element 22 is necessary. For example, any intervention on the circulation chamber 24 only requires the removal of the second casing element 22 without disassembling the internal components of the electric machine within the first casing element 12.

[0067] As we have seen, the first housing element 12 is configured to allow the housing 10 to be attached to a component of said vehicle. To this end, the first housing element 12 includes a mounting wall 26 for attaching the housing 10 to the component of said vehicle. Preferably, the mounting wall 26 extends transversely with respect to the axis A of the tubular part 16, that is to say, in the transverse plane defined by the directions B, C.

[0068] Without limiting the invention, the fixing wall 26 can be fixed to the vehicle component by either of its sides, or by its edges.

[0069] The second housing element 22 could be attached directly to the vehicle component. However, preferably, the second housing element 22 is attached to the first casing element 12 so as to constitute a casing 10 which can be removed as a single unit from the vehicle component.

[0070] The mounting wall 26 is arranged at a first axial end 28 of the tubular part 16. It preferably comprises, along axis A, a first side 30 which is adapted to be fixed to the component of said vehicle. For example, the first side may have holes (not shown) adapted to be passed through by screws received in the component of the vehicle, and / or transverse tabs (not shown) having these holes.

[0071] The first side 30 of the fixing wall 26 is preferably formed into a flat wall which is able to cooperate with a complementary flat wall 31 of the vehicle component, as for example shown in [Fig.9].

[0072] The fixing wall 26 also has a second side 32, opposite the first side 30 along axis A, on which the second housing element 22 is fixed. The second side 32 therefore extends transversely with respect to the tubular part 16.

[0073] It will be understood that the fixing wall 26 could be arranged at another point on the tubular part 16, for example in an intermediate part. For example, in this case the housing 10 could comprise a single second element extending only over a part of the tubular wall, or two second housing elements 22 which would be fixed to each of the sides 30, 32.

[0074] However, the previously mentioned configuration involving the fixing of the wall 26 to the organ on the first side 30 and the fixing to a single housing element 22 on the second side 32 remains the simplest in its arrangement.

[0075] The location of the fixing wall 26 at the first end 28 of the tubular part 16 allows to locate in this wall 26 a first housing 34 for a first bearing (not shown) of the rotor 20 of the electric machine, as shown in figures 4, 5, 7, 8, 9.

[0076] The mounting wall 26 receives on its second side 32 a first end 38 of the second housing element 22, which is fixed thereto. As will be seen in the remainder of this description, the first end 38 of the second housing element 22 can be fixed there coaxially or in a plane-to-plane bearing manner.

[0077] Opposite this first end 38, the second housing element 22 has a second end 40 which has an annular transverse wall 42.

[0078] The housing 10 can be made according to three main embodiments. In each of these embodiments, the annular transverse wall 42 is centered on a second axial end 44 of the tubular part 16. Thus, the conjunction of the fixing of the first end 38 of the second housing element 22 on the fixing wall 26 and the centering of the second end 40 of the second housing element 22 on the second end 44 of the tubular part 16 ensures good coaxiality of the second housing element 22 with respect to the first housing element 12.

[0079] A particularly advantageous configuration is obtained in the third embodiment shown in [Fig. 9], which comprises a fixing of the first end 38 of the second housing element 22 to the fixing wall 26 in the form of a planar support and which further comprises a centering of the second end 40 of the second housing element 22 on the second end 44 of the tubular part 16 in the form of a centering with a short guide length 1. In this embodiment, the centering length 1 corresponds to 8 to 12% of a length L of a section of the second element 22 encircling the tubular part 16.

[0080] To ensure the protection of the stator 18 and the rotor 20, the housing 17 of the tubular section 16 is sealed. For this purpose, as illustrated in Figures 3, 5, 6, 7, 8 and 9, the tubular section 16 is closed at its second end 44 by a transverse partition 46. This transverse partition advantageously includes a second housing 48 for a second bearing of the rotor 20 of the electric machine 10.

[0081] The annular transverse wall 42 can substantially be decomposed into two zones or sections. It comprises, firstly, as shown in Figures 4, 5 and 7 to 9, a first axial section 50 by which it is centered on the second axial end 44 of the tubular part 16. In the particular case of the third embodiment offering centering with a short guide length as previously mentioned with reference to [Fig. 9], this section is therefore of length 1.

[0082] The annular transverse wall 42 secondly comprises a second axial section 52 extending axially beyond the second axial end 44 of said tubular part 16.

[0083] This axial section 52 supports the transverse partition 46 which closes the housing 17.

[0084] In the first embodiment of the housing 10 which has been shown in figures 3 and 5, the transverse partition 46 is referred to the second axial section 52. The transverse partition 52 is for example made in the form of a disc whose outer peripheral bearing surface 54 is fitted into the second axial section 52.

[0085] In the second embodiment of the housing 10 which has been shown in figures 6 to 8 and in the third embodiment of the housing 10 which has been shown in [Fig.9], the transverse partition 46 and the second axial section 52 are in continuity of material.

[0086] In each of these first two embodiments, the transverse partition 46 extends inside the tubular part 16. For this purpose, it includes an internal peripheral span 56 which is fitted into the tubular part 16.

[0087] In the first two embodiments, the transverse partition 46 delimits, with the first axial section 50 of the annular transverse wall 42, a groove annular 58 which receives the second axial end 44 of said tubular part 16, which makes it possible to reinforce the assembly of the second element 22 on the first element 12.

[0088] In the third embodiment of the invention which has been represented in [Fig.9], the transverse partition 46 is instead arranged at a distance d from the second end 44 of the tubular part 16.

[0089] It will also be noted that, without limiting the invention or having been shown in the figures, the transverse partition 46 can also participate in the fixing of the electrical machine 12, in the same way as the fixing wall 26. It is for example possible to fix tabs or any other means of fixing it allowing it to be connected to a part of the vehicle.

[0090] In all embodiments of the invention, the sealing of the housing 17 is ensured. To this end, a first sealing system 60 is interposed between the fixing wall 26 and the first axial end 28 of said tubular part 16,

[0091] Conversely, a second sealing system 62 is interposed between the annular transverse wall 42 and the second axial end 44 of said tubular part 16.

[0092] It is important that the two sealing systems 60, 62 not be oriented in the same direction for assembly reasons. Indeed, since the assembly of the second housing element 22 onto the first housing element 12 is achieved by sliding, a different orientation of the two sealing systems 60, 62 allows them to absorb the micro-deformations of the second housing element in all directions.

[0093] Incidentally, the orientation of two sealing systems 60, 62 in two different directions makes it possible to avoid losses of sealing due to micro-deformations of the first and second housing elements 12, 22.

[0094] For this purpose, one of the first and second sealing systems 60, 62 comprises a radial compression annular seal and the other comprises an axial compression annular seal.

[0095] Thus, in the first and second embodiments of the invention which have been represented in figures 4, 5, 7, 8, the first sealing system 60 comprises an annular radial compression seal 64 interposed radially between a shoulder bearing surface 68 extending from the second side 32 of the fixing wall 26 and the first end 38 of the second housing element 22.

[0096] Conversely, in these first and second embodiments of the invention, the second sealing system 62 comprises an annular collar 70 of the annular part 16, arranged near the second axial end 44 of said tubular part 16, and which extends radially to the second housing element 22. An axial compression seal 66 is interposed axially between this collar 70 and the annular transverse wall 42 of the second housing element 22.

[0097] In these two embodiments, it will be understood that the circulation chamber 24 extends axially between the fixing wall 26 and said annular collar 70.

[0098] The configuration is different in the third embodiment of the housing 10 which has been shown in [Fig.9]. In this case, the first sealing system comprises an axial compression annular seal interposed axially between the second side 32 of the fixing wall 26 and the first axial end 38 of the second element 22. This seal is, for example, a flat annular seal, which has not been shown in [Fig.9], but it could be an O-ring.

[0099] In this third embodiment of the housing 10, the second sealing system includes an annular seal (not shown in [Fig.9]) which is interposed radially between the first section 50 of the annular transverse wall 45 and the second axial end 44 of the tubular part 16.

[0100] In this third embodiment, the alignment of the rotor shaft, and consequently the regularity of the value of its air gap with the stator, depends, as in the other embodiments, on the coaxiality of the first bearing housing 34 and second bearing housing 48. However, in this third embodiment, compared to the two previous ones, the second housing element 22 is centered only on the second axial end 44 of said tubular part due to the planar support between the second housing element 22 and the second opposite side 32 of the fixing wall 26, given the absence of a shoulder on the fixing wall 22, as is the case in the two previous embodiments.

[0101] Moreover, the transverse partition 46 and the second axial section 52 in this embodiment are, as we have seen, in continuity of material.

[0102] Consequently, the chain of dimensions which links the first bearing housing 34 to the second bearing housing 48 has one less link than in the case of the second embodiment, due to the absence of a shoulder on the fixing wall 22, and two less links than in the case of the first embodiment, due to the absence of a shoulder on the fixing wall 22 and the absence of an added transverse partition 46.

[0103] In the third embodiment, since the dimension chain between these two bearing housings is shorter, the dimensional variations associated with the two aforementioned embodiments are eliminated from this chain. It is therefore possible to achieve better coaxiality between the first bearing housing 34 and the second bearing housing 48, which allows for a reduced air gap between the rotor and the stator, and consequently, improved efficiency of the electric machine.

[0104] The arrangement of the circulation chamber 24 around the first casing element 12 by a simple mounting of the second casing element 22 around the first casing element 12 makes it possible to simplify the mounting of the electric machine by providing hydraulic connections to the circulation chamber 24 which are arranged externally to the electric machine 10, outside of the second casing element 22.

[0105] Similarly, electrical connections to the electric machine 10 can be arranged outside the second housing element 22. In the same spirit, as illustrated in [Fig.9], the second housing element 22 can include a housing 72 for a motor management electronics module (not shown) of the electric machine 12, this motor management module being a power module, a DC / DC converter, a charger or any other module.

[0106] Finally, it should be noted that the mounting of the second housing element 22 around the first housing element 12 and the arrangement of the circulation chamber 24 around the first housing element 12 allow for differential expansion of the materials of the first and second housing elements 12, 22, and consequently the use of different materials. Furthermore, since the second housing element 22 is not subjected to mechanical fastening stresses, it can be made of a material less mechanically resistant than the first housing element.

Claims

Demands

1. Housing (10) of an electric motor vehicle machine, comprising at least: - a first housing element (12), configured to allow the housing (10) to be fixed to a component (11) of said vehicle, and comprising at least one tubular portion (16) of axis A suitable for internally receiving a stator (18) of said electric machine, - at least one second substantially tubular housing element (22), mounted externally to said tubular portion (16), said at least one second housing element (22) delimiting with said first housing element (12) at least one circulation chamber (24) of a cooling fluid.

2. Housing (10) of an electrical machine according to the preceding claim, wherein said first housing element (12) comprises a fixing wall (26) allowing the housing (10) to be fixed to the component (11) of said vehicle.

3. Housing (10) of an electrical machine according to any one of the preceding claims, wherein said at least one second housing element (22) is fixed to the first housing element (12).

4. Housing (10) of an electric machine according to any one of claims 2 or 3, wherein the fixing wall (26) extends transversely with respect to the axis A of the tubular part (16).

5. Housing (10) of an electrical machine according to any one of claims 2 to 4, wherein the fixing wall (26) is arranged at a first axial end (28) of said tubular part (16).

6. Housing (10) of an electrical machine according to any one of claims 2 to 4, wherein a first side (30) of the fixing wall (26) is formed into a flat wall suitable for cooperating with a complementary flat wall (31) of the component (11) of the vehicle.

7. Housing (10) of an electrical machine according to the preceding claim, wherein a first end (38) of one of at least a second housing element is fixed to a second opposite side (32) of the fixing wall (26).

8. A housing (10) for an electrical machine according to the preceding claim, wherein a second end (40) of one of at least one second housing element has a transverse wall annular (42) which is centered on a second axial end (44) of said tubular part (16).

9. Housing (10) of an electrical machine according to the preceding claim, in which the tubular part (16) is closed at its second end by a transverse partition (46).

10. Housing (10) of an electric machine according to the preceding claim, in which the mounting wall (26) has a first housing (34) for a first bearing of a rotor of the electric machine and said transverse partition (46) has a second housing (48) for a second bearing of the rotor of the electric machine,

11. Housing (10) of an electrical machine according to any one of claims 9 or 10, wherein the annular transverse wall (46) comprises a first axial section (50) by which it is centered on the second axial end (44) of said tubular part (16).

12. Housing (10) of an electrical machine according to the preceding claim, wherein the annular transverse wall (46) comprises a second axial section (52) extending axially beyond the second axial end (44) of said tubular part (16).

13. Housing (10) of an electrical machine according to the preceding claim, in which the transverse partition (46) is referred to the second axial section (52).

14. Housing (10) of an electrical machine according to claim 12, in which the transverse partition (46) and the second axial section (52) are in continuity of material.

15. Housing (10) of an electrical machine according to any one of claims 9 to 14, wherein the transverse partition (46) is arranged at a distance (d) from the second end (44) of the tubular part (16).

16. Housing (10) of an electric machine according to any one of claims 9 to 14, wherein the transverse partition (46) extends inside the tubular part (16) and delimits with the first axial section (50) of the annular transverse wall (42) an annular groove (28) which receives the second axial end (44) of said tubular part (16).

17. Housing (10) of an electrical machine according to any one of claims 5 to 16, wherein a first sealing system (60) is interposed between said fixing wall (26) and the first axial end (28) of said tubular part (16).

18. Housing (10) of an electrical machine according to any one of claims 8 to 16 taken in combination with the preceding claim, wherein a second sealing system (62) is interposed between said annular transverse wall (42) and the second axial end (44) of said tubular part (16).

19. Housing (10) of an electrical machine according to claims 17 and 18 taken in combination, wherein one of the first and second sealing systems (60, 62) comprises a radial compression annular seal (64) and the other (60, 62) comprises an axial compression annular seal (66).

20. Housing (10) of an electrical machine according to any one of claims 11 to 19, wherein the first axial section (50) of the annular transverse wall (42) extends according to a centering having a short guide length (1) corresponding to 8 to 12% of a length (L) of a section of the second element (22) circumventing the tubular part (16),

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