Fluid circuit for cooling and lubricating a hybrid vehicle drive assembly.

Abstract

Title of the invention: Fluid circuit for cooling and lubricating a hybrid drive unit for a vehicle. The present invention relates to a hybrid drive unit (2) for a vehicle comprising at least one gearbox (12), a first electric machine (4) and a second electric machine (8), the first electric machine (4) being housed in a drive housing (6) of the hybrid unit, the second electric machine (8) and the gearbox (12) being housed in a gearbox housing (10), the hybrid unit comprising a heat exchanger (13) and a lubrication system comprising at least one pump (36) and a lubrication circuit (38), the lubrication circuit (38) extending at least partially through the heat exchanger (13) and the gearbox housing (10). (Figure 3)

Description

Title of the invention: Fluid circuit for cooling and lubricating a hybrid vehicle drive assembly.

[0001] The present invention relates to the field of cooling and lubrication systems for a hybrid drive assembly of a vehicle. The present invention relates more particularly to the cooling and lubrication of such a hybrid assembly using the same fluid.

[0002] Vehicles, and in particular motor vehicles, are increasingly frequently hybrid vehicles. These hybrid vehicles are set in motion by a hybrid assembly in which a main electric motor and a generator participate in setting the vehicle in motion, the main electric motor and the generator participating together or individually in transmitting torque to a gearbox in which, for example, pinions transmit the generated torque to drive shafts.

[0003] The main electric motor and the generator are elements that generate heat during their operation. This heat, in too large a quantity, is detrimental to the proper functioning of the main electric motor and the generator. It is thus known to implement cooling fluid circuits around each of these elements to cool them, each of these elements being conventionally housed in its own casing which must be cooled individually.

[0004] The gearbox is an element of the hybrid assembly within which numerous pinions are brought to be meshed and rub against each other, so that it is necessary to lubricate this gearbox, both to limit the wear of the parts and the friction forces between these parts. It is thus known to implement a lubricating fluid circuit within the gearbox to lubricate the different parts.

[0005] The implementation of these circuits generally involves a water circuit to cool the main electrical machine, another water circuit to cool the generator and an oil circuit to lubricate the gearbox. The accumulation of these circuits significantly increases the size of the hybrid assembly, the complexity of the circuits implemented and the risk of leaks.

[0006] The present invention falls within this context and proposes to overcome at least some of the drawbacks of the prior art. The present invention proposes in particular to reduce the number of circuits used to cool and lubricate the hybrid assembly.

[0007] Thus, the present invention relates to a hybrid drive assembly for a vehicle comprising at least one gearbox, a first electric machine and a second electric machine, the first electric machine being housed in a drive housing of the hybrid assembly, the second electric machine and the gearbox being housed in a gearbox housing of the hybrid assembly, the drive housing and the gearbox housing being separate from each other, the hybrid assembly comprising a heat exchanger external to the drive housing and the gearbox housing, the hybrid assembly comprising a lubrication system comprising at least one pump and a lubrication circuit, the pump being configured to circulate a lubricating fluid in the lubrication circuit, the lubrication circuit extending at least partly through the heat exchanger, the drive housing and the gearbox housing.

[0008] It is understood that the first electrical machine is housed in an internal volume defined by the walls of the drive housing and that the second electrical machine and the gearbox are both housed in the internal volume defined by the walls of the gearbox housing. In other words, the first electrical machine is in one compartment and the second electrical machine and the gearbox are in another compartment.

[0009] It should be noted that the heat exchanger is an element of the hybrid assembly separate from the drive casing and the gearbox casing, that is to say that this heat exchanger is an element external to the internal volume defined by each of these casings.

[0010] The pump of the lubrication system is fluidically connected to the gearbox housing such that the lubricating fluid present in the gearbox housing can be circulated in the lubrication circuit by means of the pump. This pump may be internal to the gearbox housing, and in particular arranged against a bottom wall of the housing, or external to this gearbox housing, and fluidically connected to the housing via an orifice provided near the bottom wall of the housing.

[0011] The lubrication circuit passes through both the heat exchanger and the gearbox housing and it allows lubricating fluid to be directed onto the electrical machine present within the gearbox housing. In this way, the temperature regulation of the electrical machine and the lubrication of the gearbox are advantageously achieved with the same fluid. More particularly, the lubricating fluid can be cooled within the external heat exchanger to be brought to a suitable temperature for cooling the electrical machine, and this exchange of calories has the advantage of raising the temperature of the lubricating fluid to give it viscosity properties suitable for lubricating the elements of the gearbox onto which the lubricating fluid is directed at the outlet of the electrical machine present in the gearbox housing.

[0012] According to a characteristic of the invention, the lubrication circuit extends at least partly through the heat exchanger, the gearbox housing and the drive housing. The circulation of the lubricating fluid thus takes place throughout the entire hybrid assembly. The passage of the lubrication circuit, successively through each of these different elements of the hybrid assembly, makes it possible to ensure a plurality of functions by minimizing the number of fluid circuits involved in these functions.

[0013] According to a characteristic of the invention, the lubrication circuit extends at least partly in a wall of the gearbox housing, the lubrication circuit comprising projection means configured to project lubricating fluid towards the second electric machine. The arrangement of the lubrication circuit within the wall of the gearbox housing makes it possible to limit the use of external hydraulic connections which may be subject to leaks. It is understood that a major part of the lubrication circuit is directly provided in the wall of the housing, during the manufacture of said housing for example. The projection means may be formed of simple orifices through which the lubricating fluid flows towards the second electric machine or else be formed by projection nozzles projecting the lubricating fluid at a determined pressure towards the second electric machine.

[0014] According to a characteristic of the invention, the lubrication circuit comprises at least one point of divergence at which a first part of the lubrication circuit extends towards the second electrical machine and a second part of the lubrication circuit extends towards the drive housing.

[0015] According to a characteristic of the invention, the second part of the lubrication circuit circulates in a primary shaft of the gearbox extending at least partly in the drive casing and being linked in rotation to the first electric machine. It is understood that the primary shaft of the gearbox comprises a hollow portion within which the lubrication circuit passes and more particularly the second part of the lubrication circuit. The primary shaft of the gearbox is arranged partly in the drive casing, where it is linked to the first electric machine, and partly in the gearbox casing, where it is linked to gears of the gearbox.The lubricating fluid flowing within the primary shaft is intended to pass through the drive housing to exit into the gearbox housing, the portion of the primary shaft present in the gearbox housing being radially perforated to allow passage of the lubricating fluid.

[0016] According to a characteristic of the invention, the primary shaft of the gearbox extends in a longitudinal main elongation direction, the long end tudinal of the primary shaft of the gearbox arranged in the drive housing being covered by a cover attached to the drive housing, the second part of the lubrication circuit extending partly into the cover. In particular, the cover comprises a sealing element which cooperates with the primary shaft to ensure continuity in the circulation between the part of the lubrication circuit extending within a wall of the cover and the part of the lubrication circuit extending inside the primary shaft.

[0017] According to a characteristic of the invention, the first electric machine is an axial flux electric machine.

[0018] According to a characteristic of the invention, the first electrical machine comprises a rotor and a stator, the stator comprising a first stator element housed in a first chamber and a second stator element housed in a second chamber, the second part of the lubrication circuit extending at least partly through one of said chambers. It is understood that at least the first chamber or the second chamber is part of the lubrication circuit. The lubricating fluid is directly in contact with the stator element associated with said chamber.

[0019] According to a characteristic of the invention, the lubricating fluid is a dielectric fluid.

[0020] According to a characteristic of the invention, at least a portion of the second part of the lubrication circuit is external to the drive housing and the gearbox housing. This portion of the lubrication circuit is formed by a hydraulic connection such as a hose.

[0021] According to a characteristic of the invention, at least one portion of the second part of the lubrication circuit external to the drive housing and to the gearbox housing is connected to the cover. In other words, this portion external to the drive housing extends via a hose from the point of divergence to a connection end piece present on the cover. The lubricating fluid then circulates in the cover and then in the primary shaft via the sealing element.

[0022] According to a characteristic of the invention, the second part of the lubrication circuit extends at least in one wall of the drive housing and in one wall of the gearbox housing. In particular, the second part of the lubrication circuit has a portion which extends in a sealed manner at the junction between a wall of the drive housing and a wall of the gearbox housing.

[0023] According to a characteristic of the invention, one of the chambers communicates with an evacuation duct opening into the cover. The second part of the lubrication circuit thus passes through one of the chambers, which forms a relay between a duct formed within the drive housing and a duct formed within the cover, in particular to fill the interior of the primary shaft with lubricating fluid. gearbox located opposite this cover.

[0024] According to a characteristic of the invention, one of the chambers communicates with a communication duct opening into the gearbox housing. In this way, a third part of the lubrication circuit is formed, which extends in parallel with the second part of the lubrication circuit, and which is intended to regulate the temperature of another chamber of an electric machine and to lubricate another zone of the gearbox.

[0025] The invention also relates to a vehicle comprising a hybrid assembly conforming to any one of the aforementioned characteristics.

[0026] Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows on the one hand, and examples of embodiment given for informational and non-limiting purposes with reference to the appended schematic drawings on the other hand, in which:

[0027] [Fig-1] schematically represents a sectional view of a hybrid assembly according to an embodiment of the invention, in which a lubrication system is configured to cool a second electric machine and to lubricate a gearbox, a first electric machine being cooled by a separate water circuit;

[0028] [Fig.2] schematically represents the circulation of a lubricating fluid within of the lubrication system according to the embodiment shown in [Fig.l];

[0029] [Fig.3] schematically represents a sectional view of a hybrid assembly according to another embodiment of the invention, in which the lubrication system is this time configured to cool the first electric machine and the second electric machine and to lubricate the gearbox;

[0030] [Fig.4] and a detailed view of [Fig.3], which makes more particularly visible the lubrication system at the first electric machine;

[0031] [Fig.5] schematically represents the circulation of the lubricating fluid within of the lubrication system according to the embodiment shown in [Fig.3].

[0032] The features, variants and different embodiments of the invention may be combined with each other, in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the state of the art.

[0033] In the figures, the elements common to several figures retain the same reference.

[0034] In the following description, reference will be made to an orientation as a function of the axes Longitudinal, Vertical and Transverse as arbitrarily defined by the trihedron L, V, T shown in Figures 1 to 4.

[0035] Figures 1 and 2 show a hybrid assembly 2 according to one embodiment of the invention. More specifically, [Fig. 1] shows a sectional view of the hybrid assembly 2 and [Fig. 2] shows a schematic view of the circulation of at least one lubricating fluid within the hybrid assembly 2 shown by [Fig. 1]. It should be noted that in [Fig. 2] the circulation of the fluids involved in the hybrid assembly 2 is shown by solid arrows.

[0036] This hybrid assembly 2 comprises in particular a first electric machine 4 housed in a drive casing 6, a second electric machine 8 and a gearbox 12 housed in a gearbox casing 10 and a heat exchanger 13 external to the drive casing 6 and to the gearbox casing 10.

[0037] The first electrical machine 4 is an axial flux electrical machine. This first electrical machine 4 comprises on the one hand a rotor formed by a rotor disc 14 connected in rotation with a primary shaft of the gearbox 16 and on the other hand a stator 18 comprising a first stator element 20 and a second stator element 22 arranged axially one after the other, on either side of the rotor disc 14.

[0038] The first stator element 20 comprises a wound stator body housed in a first chamber 24 and the second stator element 22 comprises a wound stator body housed in a second chamber 26, the rotor disk 14 interposed between the stator elements participating in delimiting each of the two chambers 24, 26. As visible in [Fig. 4] in particular, which is a detailed view of the hybrid assembly which relates particularly to the first electrical machine, a seal 25, 27 is arranged in each of these first and second chambers 24, 26 to prevent a cooling fluid present in the chamber from flowing by gravity to the center of the drive casing 6 towards the primary shaft 16.

[0039] The first chamber 24 thus extends on the periphery of the internal volume of the drive casing, around the primary shaft 16, being delimited radially on one side by the seal 25 which is specific to it and on the other side by an axial wall 61 of the drive casing 6, and being delimited axially by the rotor disk 14 and by a first radial wall 62 of the drive casing, facing towards the outside of the hybrid assembly.

[0040] The second chamber 26 also extends on the periphery of the internal volume of the drive casing, around the primary shaft 16, being delimited radially by the seal 27 which is specific to it and by an axial wall of the drive casing, in the extension of the axial wall 61 which participates in delimiting the first chamber 24, and being delimited axially by the rotor disk 14 and by a second wall radial 63 of the drive housing, opposite the gearbox housing 10.

[0041] The winding of the stator 18 is electrically powered by electrical connection means, not shown here, such that a magnetic field is generated at the level of the first and second stator elements 20 and 22. This magnetic field is configured to set the rotor disk 14 in motion around an axis of rotation 28.

[0042] The rotor disc 14 is linked in rotation with the primary shaft of the gearbox 16 in such a way that the axis of rotation 28 of the rotor disc 14 is coaxial with the axis of rotation of the primary shaft of the gearbox 16. It is understood that the rotation of the rotor disc 14 causes the rotation of the primary shaft of the gearbox 16.

[0043] As visible in [Fig.l], the primary shaft of the gearbox 16 extends in a longitudinal main elongation direction, that is to say parallel to the axis L, partly in the drive casing 6 and partly in the gearbox casing 10. More specifically, the primary shaft of the gearbox 16 is connected in rotation at a longitudinal end to the first electrical machine 4, and more specifically to the rotor disk 14, and by a longitudinal end opposite the gearbox 12. For this purpose, the primary shaft 16 passes through the second radial wall 63 of the drive casing, as well as a radial wall of the gearbox casing 10 arranged opposite this second radial wall 63.

[0044] In the example illustrated, without this being limiting of the invention, the gearbox 12 comprises a first secondary drive shaft 30 and a second secondary drive shaft 32 each extending parallel to the primary shaft of the gearbox 16. The first secondary drive shaft 30 is able to be connected in rotation, on the one hand with the primary shaft of the gearbox 16 and on the other hand, with the second electric machine 8. The second secondary drive shaft 32 is able to be connected in rotation on the one hand, with the primary shaft of the gearbox 16 and on the other hand, with a transmission shaft 34. This transmission shaft 34 makes it possible to transmit the torque generated by the first electric machine 4 and the second electric machine 8 to the wheels of the vehicle to set it in motion.

[0045] It should be noted that the gearbox 12 comprises a plurality of dog clutches, fixed gears and idler gears ensuring the passage of the torque generated by the first electric machine 4 and by the second electric machine 8 to the transmission shaft 34n, and that these dog clutches and gears are here shown schematically or not shown, in particular in FIGS. 1 and 3, to make the other components of the hybrid assembly more visible. This torque is transmitted to the transmission shaft 34, where appropriate by increasing or reducing the rotation speed of the transmission shaft 34 according to the fixed or idle gears engaged by the dogs.

[0046] It is understood that the movement of all of these elements within the gearbox 12 requires adequate lubrication to limit the impact of the friction forces of the parts relative to each other.

[0047] For this purpose, the hybrid assembly 2 comprises a lubrication system comprising at least one pump 36 and a lubrication circuit 38, shown in more detail in [Fig. 2]. The pump 36 is configured to allow the circulation of a lubricating fluid in the lubrication circuit 38. In the embodiment shown, the pump 36 makes it possible to recirculate the lubricating fluid that has fallen by gravity to the bottom of the gearbox housing 10, that is to say in the embodiment shown at the level of the transmission shaft 34.

[0048] The lubricating fluid circulated by the pump 36 is sent into the lubrication circuit 38 towards the heat exchanger 13. At this heat exchanger 13, a heat exchange takes place between the lubricating fluid and a heat transfer fluid. It should be noted that this portion of the lubrication circuit 38 joining the pump 36 and the heat exchanger 13 is external to the gearbox casing 10.

[0049] The lubricating fluid having carried out a heat exchange within the heat exchanger 13 circulates in the lubrication circuit 38 until it reaches a point of divergence 40 at which the lubrication circuit 38 separates into a first part 42 and a second part 44. In the embodiment illustrated in FIGS. 1 and 2, this point of divergence 40 is formed outside the gearbox housing 10 while in the embodiment illustrated in FIGS. 2 to 5, this point of divergence is formed within the gearbox housing.

[0050] The first part 42 of the lubrication circuit 38 extends at least in part, in the form of a pipe, in a wall of the gearbox casing 10 defining an internal volume in which the second electrical machine 8 and the gearbox 12 are located. Furthermore, said wall of the gearbox casing 10 comprises projection means 46 configured to project the lubricating fluid, circulating in the first part 42 of the lubrication circuit 38, towards the second electrical machine 8.

[0051] These projection means 46 may be, as shown, orifices provided in the wall of the gearbox casing 10. More precisely, these orifices open at one end into the first part 42 of the lubrication circuit 38 and at an opposite end into the gearbox casing 10. It is understood that these projection means 46 allow the lubricating fluid to flow from the first part 42 of the lubrication circuit 38 to the second electrical machine 8. Alternatively, these projection means 46 may be formed by nozzles of projection spraying the lubricating fluid towards the second electric machine 8. It is notable that the lubricating fluid is a dielectric fluid making it possible not to alter the operation of the second electric machine 8.

[0052] The first part 42 of the lubrication circuit 38 thus extends from the point of divergence 40 to the projection means 46.

[0053] At the outlet of these projection means 46, the contact of the lubricating fluid with the second electric machine 8 generates a heat exchange between the lubricating fluid and the second electric machine 8. This heat exchange can, if necessary, make it possible to regulate the temperature of the second electric machine 8 while modifying the temperature of the lubricating fluid in desired proportions. In particular, the lubricating fluid can cool the second electric machine, and even more so when the lubricating fluid has been previously cooled in the heat exchanger 13. The lubricating fluid, heated by this exchange of calories with the second electric machine and made less viscous, then flows by gravity to the gearbox 12 so that the lubricating fluid makes it possible to lubricate the gearbox 12.It is notable that the increase in the temperature of the lubricating fluid was able to give the lubricating fluid a viscosity suitable for lubricating the gearbox 12.

[0054] It is understood that the gearbox 12 is arranged, when the hybrid assembly 2 equips the vehicle, below the second electric machine 8 relative to the vertical axis V, so that the lubricating fluid flows by gravity from the second electric machine to the various pinions of the gearbox.

[0055] The lubricating fluid is then recovered at the bottom of the casing by the pump 36 and reinjected into the lubrication circuit.

[0056] The second part 44 of the lubrication circuit 38 extends from the point of divergence 40 to the drive casing 6. More specifically, in the embodiment shown in Figures 1 and 2, the second part 44 of the lubrication circuit 38 extends externally to the drive casing 6 and to the gearbox casing 10 and is formed, for example, by a hose, while in the embodiment shown in Figures 3 to 5, the second part 44 of the lubrication circuit extends internally, in particular through several successive walls forming the drive casing 6 and the gearbox casing 10.

[0057] The second part 44 of the lubrication circuit 38 will be described initially with reference to FIGS. 1 and 2. The second part 44 of the lubrication circuit 38, which extends outside the casings from the point of convergence, in particular in the form of a hose, reaches the drive casing 6 at a cover 48 associated with this drive casing. This cover 48 is fixed to the first radial wall 62 of the drive casing 6, so as to cover, in the longitudinal direction, the primary shaft of the gearbox 16.

[0058] The hose forming the second part 44 is connected to an end piece secured to the cover and which allows fluid communication between the hose and a channel internal to the cover which extends the second part 44 of the lubrication circuit 38. This internal channel opens onto a hollow portion 50 of the primary shaft of the gearbox 16, this junction being made watertight by a sealing element fixed to the cover and which, in the embodiment shown, is formed of a lip ring 51.

[0059] In other words, in this embodiment, the second part 44 of the lubrication circuit 38 thus extends from the point of divergence 40 to the sealing element associated with the cover 48 and the hollow portion 50 of the primary shaft, being produced successively by a flexible pipe external to the different casings of the hybrid assembly of the invention and by a pipe formed within a cover covering the primary shaft.

[0060] The lubrication circuit 38 also extends into the hollow portion 50 of the primary shaft of the gearbox 16, which, as a reminder, is driven in rotation by the first electrical machine 4. The hollow portion 50 of the primary shaft of the gearbox 16 comprises openings, not shown here, opening at one end into the hollow portion 50 of the primary shaft of the gearbox 16 and at an opposite end into the gearbox casing 10.

[0061] It is understood that the lubricating fluid is projected, by means of said openings, into the gearbox casing 10 and that it then flows to the previously mentioned bottom of said gearbox casing 10. The lubricating fluid is then taken by the pump 36 and returned to the lubrication circuit 38 cyclically.

[0062] It should be noted that the projection of the lubricating fluid from the hollow portion 50 is, when the primary shaft of the gearbox 16 is driven in rotation, facilitated by the centrifugal force exerted by the primary shaft of the gearbox 16 on the lubricating fluid. In addition, the rotation of the primary shaft of the gearbox 16 makes it possible to uniformly project the lubricating fluid throughout the entire gearbox housing 10.

[0063] As mentioned previously, in the embodiment shown in Figures 1 and 2, the lubricating fluid makes it possible to carry out a heat exchange with the second electric machine 8 and to lubricate the gearbox 12. Concerning the lubrication of the gearbox 12, the lubricating fluid performs this function on the one hand by flowing by gravity from the second electric machine 8 and on the other hand by being projected from the hollow portion 50 of the primary shaft of the gearbox 16 through the openings mentioned.

[0064] The cooling of the first electrical machine 4 is ensured, in the embodiment shown, by a water circuit 52, independent of the lubrication circuit and in which a cooling fluid circulates. The cooling fluid circulates in the wall of the drive casing 6, and more particularly in the walls of said drive casing 6 adjoining the first stator element 20 and the second stator element 22.

[0065] We will now describe, with reference to Figures 3 to 5, a particular embodiment of the invention in which the cooling of the second electrical machine 8 and the lubrication of the gearbox is still ensured by the lubricating fluid circulating in the lubrication circuit 38, but in which, moreover, the cooling of the first electrical machine 4 is also ensured by this lubricating fluid, by means of a structural modification of the lubrication circuit.

[0066] The lubrication circuit 38 is notably modified in that it no longer comprises a flexible hose external to the casings but is integrated into the casings, with notably the second part 44 of this lubrication circuit 38 which circulates from the point of convergence 40 within walls delimiting the casings and within the chambers 24, 26 of the first electrical machine 4.

[0067] As seen in [Fig. 3], the point of divergence 40 of the lubrication circuit 38 is located in the wall of the gearbox casing 10. According to the embodiment shown in [Fig. 1], the first part 42 of the lubrication circuit 38 extends in the wall of the gearbox casing 10 in the direction of the second electric machine 8. The lubricating fluid is then projected in the direction of the second electric machine 8 from the projection means 46. The lubricating fluid then carries out a heat exchange with the second electric machine 8 and then flows by gravity to the gears of the gearbox to carry out its lubrication function.

[0068] The second part 44 of the lubricating fluid circuit this time extends, between the point of divergence 40 and the wall of the drive casing 6, within the wall of the gearbox casing 10.

[0069] At the junction between the drive casing 6 and the gearbox casing 10, sealing means are implemented to allow the continuity of the second part 44 of the lubrication circuit 38 from the wall of the gearbox casing 10 to a wall of the drive casing 6 and more particularly the axial wall 61 participating in radially delimiting both the first chamber 24 and the second chamber 26.

[0070] This portion of the second part 44 of the lubrication circuit 38 entering the wall of the drive casing 6 separates into a first branch 54 and a second branch 56. The first branch 54 is fluidically connected to the first chamber 24 of the stator 18 of the first electrical machine 4 and the second branch 56 is connected to the second chamber 26 of this stator.

[0071] It should be noted that the first branch 54 comprises at least one first hole opening at one end into the first branch 54 and at an opposite end into the first chamber 24. Similar to the first branch 54, the second branch 56 comprises a second hole opening at one end into the second branch 54 and at an opposite end into the second chamber 26. Where appropriate, projection nozzles may be provided in place of the holes to allow the projection of the lubricating fluid onto the windings of the stator elements present in each chamber 24, 26.

[0072] It is understood that the first stator element 20 and the second stator element 22 each carry out a heat exchange with the lubricating fluid which comes directly into contact with said stator elements 20 and 22. Here again, it is notable that the lubricating fluid is a dielectric fluid making it possible not to alter the operation of said stator elements 20, 22.

[0073] Each chamber is filled with lubricating fluid, in which the stator elements are bathed, the lubricating fluid being retained in particular in each chamber by the seals 25, 27 which seal their respective chamber in the vicinity of the rotor disk 14. The lubricating fluid present in each chamber and raised in temperature by the calories recovered from the corresponding stator element is progressively replaced by the lubricating fluid, at a lower temperature, arriving through the openings or nozzles at the end of the branches 54, 56. The arrival of fluid, under pressure, helps to push a part of the fluid present in each chamber to allow its replacement as it progresses.

[0074] At least one outlet is provided in each chamber to allow the exit of a portion of the lubricating fluid.

[0075] As illustrated in particular by arrows visible in [Fig. 4], the lubricating fluid present in the first chamber 24 leaves the latter, under the effect of the pressure generated by fluid arriving specifically in this chamber, through a supply conduit 65 arranged both in the first radial wall 62 of the drive casing 6 and in the cover 48. The lubricating fluid pushed out of the first chamber 24 is then intended to circulate in the cover 48 and then, in accordance with what has been described in connection with [Fig. 1], enter the hollow portion 50 of the primary shaft of the gearbox 16.

[0076] As is illustrated in particular by arrows visible in [Fig.4], the lubricating fluid present in the second chamber 26 leaves the latter, under the effect of the pressure generated by fluid arriving specifically in this chamber, by a communication duct 58 formed in the second radial wall 63 of the drive casing 6 and in the radial wall of the gearbox casing 10, such that the lubricating fluid present in the second chamber 26 is sent into the gearbox casing 10 to lubricate the gearbox 12, and more particularly here within one of the secondary drive shafts 30. A stud 64 is formed projecting from the radial wall of the gearbox casing 10 to come into contact with the second radial wall 63 of the drive casing 6, opposite the part of the communication duct 58 formed in the second radial wall 63 of the drive casing 6, the stud being pierced to form a part of this communication duct 58.It should be noted that sealing means are also implemented at the junction between the wall of the drive housing 6 and the wall of the gearbox housing 10, here the stud 64, to ensure sealed circulation of the lubricating fluid within the communication duct 58.

[0077] In this embodiment, it is thus possible to identify a third part 45 of the lubrication circuit 38 formed successively by the second branch 56, the second chamber 26 of the axial drive motor and the communication conduit 58. This third part 45 makes it possible to regulate the temperature of a chamber of the first electrical machine 4 which was not regulated by the second part 44 of the lubrication circuit and also makes it possible to lubricate a secondary drive shaft, not lubricated by the second part 44 of the lubrication circuit.

[0078] In the illustrated example, it should be noted that only one orifice is formed in the first chamber 24 to communicate with the supply duct 64 and that only one orifice is formed in the second chamber 26 to communicate with the discharge duct 58. It is understood, however, that without departing from the context of the invention, each chamber could be equipped with several orifices, each communicating with a supply duct or a discharge duct. In particular, an orifice could be arranged in the vicinity of the axial wall delimiting the chambers which is intended to be arranged vertically lowest when the hybrid drive assembly is mounted on the vehicle.

[0079] In other words, in this embodiment illustrated in Figures 3 to 5, the second part 44 of the lubrication circuit 38 thus extends from the point of divergence 40 to the sealing element associated with the cover 48 and the hollow portion 50 of the primary shaft, being produced mainly within walls of casings forming the hybrid assembly of the invention and by a pipe formed within a cover covering the primary shaft, each passage from one casing to the other or from one casing to the cover being made watertight by appropriate means.

[0080] Furthermore, the second part 44 of the lubrication circuit further comprises a buffer zone of lubricating fluid formed in the first chamber 24 of the first electrical machine 4, this buffer zone being supplied by the first branch 54 and evacuated by the evacuation conduit 65.

[0081] Finally, the lubrication circuit is distinguished in that a third part 45 as mentioned extends in parallel with the second part 44.

[0082] Thus, in the embodiment shown in Figures 3 to 5, the lubricating fluid circulating in the different parts of the lubrication circuit makes it possible to carry out a heat exchange with the second electric machine 8 and to carry out a heat exchange with the first electric machine 4, it being noted that these temperature regulations are carried out substantially in parallel. During the same cycle, before reinjection via the pump 36, the lubricating fluid used to exchange calories with the first electric machine has not been heated by a prior passage within the second electric machine, and vice versa. The temperature regulation is thus particularly effective for the two electric machines because the temperature of the lubricating fluid in contact with these electric machines is substantially equal to its temperature at the outlet of the heat exchanger 13.

[0083] Furthermore, this lubricating fluid allows the lubrication of the gearbox 12 on the one hand by flowing by gravity from the second electrical machine 8, on the other hand by being projected from the hollow portion 50 of the primary shaft of the gearbox 16 through the openings mentioned, and finally by being projected from the interior of a secondary shaft.

[0084] This embodiment illustrated in Figures 3 to 5 is thus particularly advantageous in that a lubrication circuit, internal to the hybrid drive assembly and therefore without external hose penalizing the size of the hybrid assembly, makes it possible to effectively regulate the temperature of two separate electrical machines and to effectively lubricate, because it is introduced into the card from several zones, the gearbox.

[0085] The present invention achieves the aim it set itself by proposing a hybrid drive assembly for a vehicle in which the cooling of at least one of the electrical machines and the lubrication of the gearbox are carried out by the same lubrication circuit. Such pooling of the lubrication circuit to ensure both cooling and lubrication makes it possible to increase the compactness of the hybrid assembly and to reduce the risks of leakage which could occur in a hybrid assembly with multiple circuits.

Claims

Claims

1. A hybrid drive assembly (2) for a vehicle comprising at least one gearbox (12), a first electric machine (4) and a second electric machine (8), the first electric machine (4) being housed in a drive housing (6) of the hybrid assembly (2), the second electric machine (8) and the gearbox (12) being housed in a gearbox housing (10) of the hybrid assembly (2), the drive housing (6) and the gearbox housing being separate from each other, the hybrid assembly (2) comprising a heat exchanger (13) external to the drive housing (6) and the gearbox housing (10), the hybrid assembly (2) comprising a lubrication system comprising at least one pump (36) and a lubrication circuit (38), the pump (36) being configured to circulate a lubricating fluid in the lubrication circuit (38),the lubrication circuit (38) extending at least partly through the heat exchanger (13) and the gearbox housing (10).,

2. Hybrid assembly (2) according to the preceding claim, in which the lubrication circuit (38) extends at least partly in a wall of the gearbox housing (10), the lubrication circuit (38) comprising projection means (46) configured to project lubricating fluid towards the second electric machine (8).

3. A hybrid assembly (2) according to any preceding claim, wherein the lubrication circuit (38) comprises at least one divergence point (40) at which a first portion (42) of the lubrication circuit (38) extends towards the second electrical machine (8) and a second portion (44) of the lubrication circuit (38) extends towards the drive housing (6).

4. Hybrid assembly (2) according to the preceding claim, in which the second part (44) of the lubrication circuit (38) circulates in a primary shaft of the gearbox (16) extending at least partly in the drive housing (6) and being linked in rotation to the first electric machine (4).

5. Hybrid assembly (2) according to the preceding claim, in which the primary shaft of the gearbox (16) extends in a longitudinal main elongation direction, the longitudinal end of the primary shaft of the gearbox (16) arranged in the casing drive (6) being covered by a cover (48) attached to the drive housing (6), the second part (44) of the lubrication circuit (38) extending partly into the cover (48).

6. Hybrid assembly (2) according to any one of claims 1 to 5, in combination with claim 3, in which at least a portion of the second part (44) of the lubrication circuit (38) is external to the drive housing (6) and to the gearbox housing (10).

7. Hybrid assembly (2) according to the preceding claim, in combination with claim 5, in which the at least one portion of the second part (44) of the lubrication circuit (38) external to the drive housing and to the gearbox housing is connected to the cover.

8. A hybrid assembly (2) according to any one of claims 1 to 5, in combination with claim 3, wherein the second part (44) of the lubrication circuit (38) is formed in a wall of the gearbox housing (10) and in a wall of the drive housing (6).

9. Hybrid assembly (2) according to the preceding claim, wherein the first electrical machine (4) comprises a rotor and a stator (18), the stator (18) comprising a first stator element (20) housed in a first chamber (24) and a second stator element (22) housed in a second chamber (26), the second part (44) of the lubrication circuit (38) extending at least partly through one of said chambers (24, 26).

10. Hybrid assembly (2) according to the preceding claim, in combination with claim 5, in which one of the chambers (24, 26) communicates with an evacuation conduit (65) opening into the cover (48).

11. Hybrid assembly (2) according to claim 9 or 10, in which one of the chambers (24, 26) communicates with a communication duct (58) opening into the gearbox housing (10).

12. Vehicle comprising a hybrid assembly (2) according to any one of claims 1 to 11.

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