Dual lubricant reservoir powertrain

Abstract

Title of the invention: Powertrain with two lubricant reservoirs. The present invention relates to a powertrain (1) for a vehicle comprising at least one electric motor (2), a speed reducer (8), and a lubrication device (16) for the electric motor (2) and the speed reducer (8). The lubrication device (16) comprises a first lubricant reservoir (20), a second lubricant reservoir (22) separate from the first lubricant reservoir (20), and a pump (34) for conveying lubricant from the first lubricant reservoir (20) to the electric motor (2), the speed reducer (8), and the second lubricant reservoir (22) via a lubricant circuit (18). Abstract figure: Figure 1

Description

Title of the invention: Powertrain with two lubricant reservoirs

[0001] The present invention relates to the field of lubrication of powertrains equipping vehicles, and more particularly to the lubrication of such powertrains equipped with an electric motor and a speed reducer.

[0002] Within a powertrain, certain moving parts such as the electric motor and the gearbox require lubrication and possibly cooling. The powertrain includes a lubricant, for example oil, for this purpose, which aims to reduce friction.

[0003] This lubricant has the disadvantage of deteriorating over time. Consequently, as a precaution, powertrains generally carry a volume of lubricant that exceeds lubrication requirements. It is therefore necessary to find a compromise between a competitive powertrain design and a sufficient volume of lubricant on board. Furthermore, an excessive volume of lubricant within the powertrain can be problematic, as this lubricant is displaced during vehicle movement, for example, when cornering or going downhill. Such lubricant displacement can lead to a churning phenomenon, resulting in a loss of powertrain efficiency. In the case of an electric motor, such lubricant displacement can lead to the presence of lubricant in the air gap, which reduces the efficiency and performance of the electric motor.

[0004] The present invention aims to overcome these drawbacks by proposing a powertrain that includes two separate lubricant reservoirs, which allows the powertrain to have a sufficient volume of lubricant without hindering its performance.

[0005] The main object of the present invention is a vehicle powertrain comprising at least one electric motor, a speed reducer and a lubrication device for the electric motor and the speed reducer, the lubrication device comprising a first lubricant reservoir, a second lubricant reservoir separate from the first lubricant reservoir, and a pump for conveying lubricant from the first lubricant reservoir to the electric motor, the speed reducer and the second lubricant reservoir via a lubricant circuit.

[0006] The powertrain is intended to equip a vehicle, for example a motor vehicle. The powertrain according to the invention can be lubricated, or even The system is cooled either directly by the lubricant from the first lubricant reservoir or by the lubricant that has passed through the second lubricant reservoir. The pump delivers lubricant from this first lubricant reservoir to this second lubricant reservoir.

[0007] The first lubricant reservoir thus allows lubricant to be supplied to the electric motor, to the gearbox, and / or to the second lubricant reservoir, while the lubricant from the second reservoir is intended solely for this gearbox. The first lubricant reservoir is, for example, an oil tank, i.e., an open reservoir, while the second lubricant reservoir is a closed reservoir.

[0008] Such an arrangement of the lubrication system makes it possible to limit the quantity of lubricant in the first lubricant reservoir, which is an open reservoir, and therefore to limit the risk of splashing in the electric motor of the powertrain, for example, during lubricant flow. Splashing is undesirable in the case of the electric motor because the aim is to avoid the presence of lubricant between a rotor and a stator of this electric motor, that is to say, at its air gap.

[0009] The second lubricant reservoir is configured to serve as a reserve of lubricant that can be used when the pump is not operating. When the pump is not running, the presence of the second reservoir allows the gearbox to be lubricated by gravity flow. This solution is particularly advantageous when the lubricant is too cold to be pumped efficiently, as the passage of the lubricant through the gearbox contributes to raising its temperature. Similarly, lubricating the gearbox via the second lubricant reservoir in the event of a pump failure improves the reliability of the powertrain. Indeed, even if the electric motor is not lubricated, the gearbox will be.

[0010] According to one feature of the invention, the pump is arranged on the lubricant circuit between the first lubricant reservoir and the second lubricant reservoir.

[0011] As mentioned previously, the pump is configured to draw from the first lubricant reservoir to supply the second lubricant reservoir. This pump can be linked to the operation of the powertrain, but it can also be rotated by an electric actuator independent of the powertrain.

[0012] According to another feature of the invention, the second lubricant reservoir is intended to supply lubricant to the speed reducer by means of a gravity flow of lubricant.

[0013] For this purpose, the second lubricant reservoir is arranged above the first lubricant reservoir when these two reservoirs are mounted on the vehicle they This arrangement is assessed along a vertical direction, which is a direction perpendicular to the ground on which the vehicle rests. The second lubricant reservoir is also positioned above the gearbox; thus, when the lubricant flows from this second reservoir by gravity, it lubricates the gearbox.

[0014] According to one feature of the invention, the lubricant circuit includes at least one main branch for supplying lubricant to the electric motor and / or the speed reducer, and a supplementary branch for supplying lubricant to the second lubricant reservoir.

[0015] It is understood here that the lubricant circuit has several branches, including a main branch and a secondary branch. The main branch lubricates either the electric motor, the gearbox, or both. The secondary branch supplies lubricant to the second lubricant reservoir, which in turn lubricates the gearbox.

[0016] According to another feature of the invention, the lubricant circuit includes a lubrication chute for the speed reducer and / or the electric motor, the main branch and the second lubricant reservoir both supplying lubricant to this lubrication chute.

[0017] Thus, this lubrication channel constitutes a junction point of the lubrication device in which the lubricant circulating in the main branch and the lubricant circulating in the second lubrication reservoir meet.

[0018] According to one feature, the lubrication chute includes two supply nozzles, among which a first nozzle intended to supply lubricant to a first portion of the speed reducer and a second nozzle intended to supply lubricant to a second portion of the speed reducer.

[0019] The lubricant circulating in the lubrication channel can therefore supply two distinct portions of the speed reducer. Since this lubrication channel is a junction point between the main branch and the second lubricant reservoir, it is understood that the lubricant from the main branch can lubricate both the first and second portions of the speed reducer, and that similarly the lubricant from the second lubricant reservoir supplies each of the first and second portions of the speed reducer.

[0020] According to one feature of the invention, the main branch of the lubricant circuit comprises two lubricant supply lines for the electric motor.

[0021] Like the two nozzles equipping the lubrication chute and participating in the lubrication of the speed reducer, the electric motor and more particularly the rotation bearings of the rotor of this electric motor can be supplied with lubricant. For this purpose, each of the two lubricant supply lines of the electric motor can be equipped with a lubrication nozzle.

[0022] According to another feature of the invention, the second lubricant reservoir has a lubricant outlet point which delimits within the second lubricant reservoir a lubricant accumulation zone and a lubricant circulation zone.

[0023] This accumulation zone corresponds to an area capable of collecting a portion of the lubricant, particularly to trap debris that may be contained in this lubricant. The circulation zone, for its part, is an area of ​​the second lubricant reservoir through which this lubricant flows to supply the speed reducer, via the outlet point.

[0024] The circulation zone is here arranged above the accumulation zone in the vertical direction as defined previously. The outlet point is positioned on the second lubricant reservoir according to the duration and lubricant flow requirements of the powertrain.

[0025] According to a feature of the invention, the complementary branch of the lubricant circuit opens into the lubricant circulation zone.

[0026] Such an arrangement makes it easier to circulate the lubricant within the second lubricant reservoir.

[0027] According to one feature, the second lubricant reservoir includes a vent for venting the circulation area to the air.

[0028] This vent, for example a nozzle, allows air contained in the second lubricant reservoir to enter or exit. This vent is located in the circulation area.

[0029] According to one feature of the invention, the powertrain includes a bypass channel, a first end of which opens into the circulation area of ​​the second lubricant reservoir and a second end is connected to the lubricant circuit between the first lubricant reservoir and the pump.

[0030] This bypass channel is therefore located between the second lubricant reservoir and a portion of the lubricant circuit both downstream of the first lubricant reservoir and upstream of the pump. The bypass channel prevents the pump from being supplied with lubricant that has been aerated by its circulation within the electric motor or the gearbox. Indeed, the lubricant that is delivered to the pump via this bypass channel comes directly from the second lubricant reservoir.

[0031] This bypass channel is also connected to the circulation area of ​​the second lubricant reservoir, thus preventing a complete draining of this second lubricant reservoir when the pump is not in operation.

[0032] The invention further relates to a motorized vehicle, comprising a powertrain equipped with a lubrication device as previously mentioned.

[0033] Such a motor vehicle may, for example, be a motor vehicle.

[0034] According to one feature of the invention, the second lubricant reservoir is positioned above the first lubricant reservoir in a direction perpendicular to the ground on which the vehicle rests.

[0035] The second lubricant reservoir is therefore arranged above the first lubricant reservoir in a vertical direction. This arrangement allows the lubricant flowing by gravity from the second lubricant reservoir to be collected in the first lubricant reservoir.

[0036] 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:

[0037] [Fig-1] illustrates, schematically, the powertrain according to the invention;

[0038] [Fig.2] illustrates, schematically, another view of the powertrain of the [Fig.l] according to a first embodiment;

[0039] [Fig.3] illustrates, schematically, the powertrain according to a second method of implementation.

[0040] The features, variants, and different embodiments 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 features, described hereafter in isolation 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.

[0041] In the figures, the elements common to several figures retain the same reference.

[0042] In the detailed description that follows, the terms "longitudinal," "vertical," and "transverse" refer to the orientation of the powertrain according to the invention. A longitudinal direction corresponds to a direction in which the axis of rotation of the electric motor of the powertrain is located. A vertical direction corresponds to a direction perpendicular to the ground on which the vehicle equipped with the powertrain rests. Finally, a transverse direction corresponds to a direction parallel to a transverse axis T of the L, V, T frame, this transverse axis T being perpendicular to the longitudinal axis L and to the vertical axis V.

[0043] Figure 1 schematically illustrates a powertrain 1 according to the invention in a longitudinal-vertical plane, whereas in Figures 2 and 3 this powertrain 1 is represented in a transverse-vertical plane. Figure 2 corresponds to a first embodiment of the invention, Figure 3 representing a second embodiment thereof.

[0044] The powertrain 1 is intended to equip a motorized vehicle, for example an electric vehicle 2, comprising in particular a rotor 4 and a stator 6 which contribute to the propulsion of the vehicle. The rotor 4 rotates within the stator 6 around an axis of rotation X, this axis of rotation X extending along the longitudinal direction.

[0045] The drive unit 1 further comprises a speed reducer 8 associated with the electric motor 2. This speed reducer 8 includes a differential 10 which extends along the axis of rotation X of the rotor 4. This differential 10 drives a primary shaft 12 which itself drives a secondary shaft 14. Primary shaft 12 and secondary shaft 14 extend mainly in the longitudinal direction, and their respective axes of rotation are parallel and distinct from the axis of rotation X of the rotor 4.

[0046] According to the invention, the powertrain 1 is equipped with a lubrication device 16 for lubricating and cooling the electric motor 2 and the speed reducer 8. The lubrication device 16 includes a lubricant circuit 18 which serves to deliver lubricant to the electric motor 2 and / or to the speed reducer 8. This lubricant circuit 18 thus allows lubricant to be delivered from a first lubricant reservoir 20 and a second lubricant reservoir 22 separate from this first lubricant reservoir 20. This second lubricant reservoir 22 is arranged above the first lubricant reservoir 20 in a vertical direction which corresponds to a direction perpendicular to the ground on which the vehicle equipped with the powertrain 1 according to the invention rests.

[0047] More specifically, the lubricant circuit 18 supplies lubricant from the first lubricant reservoir 20 to the electric motor 2, and supplies lubricant from both the first and second lubricant reservoirs 22 to the gearbox 8. For this purpose, the lubricant circuit 18 has a main branch 24 for supplying lubricant to the electric motor 2 and / or the gearbox 8, and a secondary branch 26 for supplying lubricant to the second lubricant reservoir 22. The main branch 24 and the secondary branch 26 separate within the lubricant circuit 18 at a junction 28. The lubricant circuit 18 also has a common section 30, through which the lubricant flows to reach either the main branch 24 or the secondary branch 26.

[0048] The first lubricant reservoir 20 is located at one end 32 of this portion common 30. This end 32 is further equipped with a filter, for example a strainer, which retains undesirable particles contained in the lubricant when it is drawn from the first lubricant reservoir 20.

[0049] Such lubricant suction involves a pump 34 which is driven by the powertrain 1 or by a dedicated electric actuator. This pump 34 is located on the lubricant circuit 18 between the first lubricant reservoir 20 and the branch 28, that is, on the common portion 30 of the lubricant circuit 18. More generally, the pump 34 is located on the lubricant circuit 18 between the first lubricant reservoir 20 and the second lubricant reservoir 22.

[0050] The pump 34 is equipped with a pressure relief valve, not shown in the figures. This pump 34 allows drawing from the first lubricant reservoir 20 either to supply the second lubricant reservoir 22 via the auxiliary branch 26, or to directly lubricate the electric motor 2 and the speed reducer 8 via the main branch 24.

[0051] The first lubricant reservoir 20 is an open reservoir, for example such as an oil tank. The gears of the speed reducer 8, in particular the differential 10, can thus be lubricated at least by splash lubrication.

[0052] Conversely, the second lubricant reservoir 22 is a closed reservoir. It thus has a bottom wall 36 and an upper wall 38 opposite this bottom wall 36, these walls 36, 38 extending mainly in a longitudinal-transverse plane. The bottom wall 36 and the upper wall 38 define between them an internal cavity 40 of the second lubricant reservoir 22. Furthermore, a dimension of the second lubricant reservoir 22, measured between its bottom wall 36 and its upper wall 38 in the vertical direction, corresponds to its height H. It is therefore understood that the height H corresponds to the vertical dimension of the internal cavity 40 of the second lubricant reservoir 22. Such a height H is, for example, approximately 50 millimeters, plus or minus 10 millimeters.

[0053] The lubricant enters the second lubricant reservoir 22 through the auxiliary branch 26, which connects to this second lubricant reservoir 22 at one of its longitudinal ends. At the opposite longitudinal end is an outlet point 42, which corresponds to an area through which the lubricant leaves the second lubricant reservoir 22. This outlet point 42 makes it possible to delineate, within the internal housing 40, a lubricant accumulation zone 44 and a lubricant circulation zone 46.

[0054] The lubricant accumulation zone 44 is a lubricant collection zone. It participates, possibly in conjunction with the strainer located at the end 32 of the common portion 30 of the lubricant circuit 18 opening into the first lubricant reservoir 20, in trapping any debris or particles present in the lubricant so that these are not directed to the components of the powertrain 1 to be lubricated and / or cooled. The lubricant circulation zone 46 is located above the lubricant accumulation zone 44 in the vertical direction. It corresponds to the area of ​​the second lubricant reservoir 22 through which the lubricant flows, from the auxiliary branch 26 to the outlet point 42. It is thus understood that the auxiliary branch 26 of the lubricant circuit 18 opens into the lubricant circulation zone 46 of the second lubricant reservoir 22.

[0055] The upper wall of the second lubricant reservoir 22 is equipped with a vent 48, which is intended to vent the lubricant circulation area 46 to the air. This vent 48 is more particularly supported by the upper wall 38 of the second lubricant reservoir 22. It allows air to circulate from or to this second lubricant reservoir 22.

[0056] Due to the arrangement of the second lubricant reservoir 22 relative to the first lubricant reservoir 20 within the lubrication device 16, namely above this first lubricant reservoir 20, this lubricant flows by gravity towards the elements of the powertrain to be lubricated.

[0057] The lubricant thus flows from the second lubricant reservoir 22 via the outlet point 42. It then passes through an overflow channel 50 connected to this outlet point 42, this overflow channel 50 opening into a lubrication chute 52.

[0058] The lubrication trough 52 can constitute a junction point between the main branch 24 and the auxiliary branch 26. In other words, both the main branch 24 and the auxiliary branch 26 supply the lubrication trough 52. More specifically, this lubrication trough 52 is supplied with lubricant via the second lubricant reservoir 22 for the auxiliary branch 26, while it is supplied via a supply conduit 54 for the main branch 24.

[0059] Alternatively, it is possible that this lubrication chute 52 is only connected to the second lubricant reservoir 22.

[0060] The lubrication chute 52 is used to lubricate the speed reducer 8. For this purpose, it has two supply nozzles 56 and 58, including a first supply nozzle 56 and a second supply nozzle 58. The first supply nozzle 56 is intended to supply lubricant to a first portion of the speed reducer 8, while the second supply nozzle 58 is intended to supply lubricant to a second portion of this speed reducer 8. As can be clearly seen in Figures 2 and 3, the first portion of the speed reducer 8 corresponds to the differential 10 and the input shaft 12, while its second portion corresponds to the output shaft 14. The first supply nozzle 56 and the second supply nozzle 58 are equipped with lubrication holes 60 which allow a lubricant flows by gravity towards the speed reducer 8.

[0061] It is therefore understood that the gearbox 8 is supplied with lubricant either directly from the first lubricant reservoir 20 via the main branch 24, or through the second lubricant reservoir 22 via the auxiliary branch 26. These two branches 24 and 26 meet at the lubrication trough 52, from which the lubricant can lubricate the gearbox 8 by flowing under gravity. Since this lubrication of the gearbox 8 relies on gravity, it can occur even when the pump 34 is not running.

[0062] In parallel with the supply conduit 54, the main branch 24 has a first supply conduit 62 and a second supply conduit 64 which are intended to supply lubricant to the electric motor 2, and more specifically to the rotating bearings of its rotor 4. In the same way as for the two supply nozzles 56, 58 of the lubrication chute 52, the presence of two supply conduits 62, 64 makes it possible to supply lubricant to the two rotating bearings of the rotor 4. To do this, each of the first supply conduit 62 and second supply conduit 64 is here equipped with a lubrication nozzle 66.

[0063] According to a particular embodiment of the invention illustrated in [Fig. 3], the powertrain 1, and more particularly the lubrication device 16, includes a bypass channel 68. This bypass channel 68 has a first end 70 and a second end 72. The first end 70 opens into the lubricant circulation zone 46 of the second lubricant reservoir 22, while the second end 72 is connected to the lubricant circuit 18 between the first lubricant reservoir 20 and the pump 34. The bypass channel 68 thus constitutes a branch of a portion of the common section 30 of the lubricant circuit 18.

[0064] The bypass channel 68 allows some of the lubricant to reach the pump 34 without passing through the speed reducer. This arrangement of the lubrication system 16 reduces lubricant aeration within the lubricant circuit 18, particularly because the lubricant flowing through it comes directly from the second lubricant reservoir 22. This bypass channel 68 also, in conjunction with the pressure relief valve on the pump 34, reduces the pressure in the common section 30 between this pump 34 and the branch 28.

[0065] The present invention thus proposes a powertrain with two separate lubricant reservoirs, which in particular allows the powertrain to be supplied with lubricant when a pump which equips it is not in operation.

[0066] However, the present invention is not limited to the means and configurations described and illustrated herein, and also extends to any means and configuration equivalents as well as any technically operative combination of such means.

Claims

Demands

1. Powertrain (1) for a vehicle comprising at least one electric motor (2), a speed reducer (8) and a lubrication device (16) for the electric motor (2) and the speed reducer (8), the lubrication device (16) comprising a first lubricant reservoir (20), a second lubricant reservoir (22) separate from the first lubricant reservoir (20), and a pump (34) for conveying lubricant from the first lubricant reservoir (20) to the electric motor (2), the speed reducer (8) and the second lubricant reservoir (22) via a lubricant circuit (18), the lubricant circuit (18) comprising at least one main branch (24) for supplying lubricant to the electric motor (2) and / or the speed reducer (8), and one auxiliary branch (26) for supplying lubricant to the second lubricant reservoir (22),the lubricant circuit (18) comprising a lubrication channel (52) for the speed reducer (8) and / or the electric motor (2), the main branch (24) and the second lubricant reservoir (22) both supplying lubricant to this lubrication channel (52).

2. Powertrain (1) according to claim 1, wherein the pump (34) is disposed on the lubricant circuit (18) between the first lubricant reservoir (20) and the second lubricant reservoir (22).

3. Powertrain (1) according to any one of claims 1 and 2, wherein the second lubricant reservoir (22) is intended to supply lubricant to the speed reducer (8) by gravity flow of the lubricant.

4. Powertrain (1) according to any one of claims 1 to 3, wherein the lubrication chute (52) comprises two supply nozzles (56, 58), of which a first nozzle (56) intended to supply lubricant to a first portion of the speed reducer (8) and a second nozzle (58) intended to supply lubricant to a second portion of the speed reducer (8).

5. Powertrain (1) according to any one of claims 1 to 4, wherein the main branch (24) of the lubricant circuit (18) comprises two lubricant supply lines (62, 64) for the electric motor (2).

6. Powertrain (1) according to any one of claims 1 to 5, wherein the second lubricant reservoir (22) has a lubricant outlet point (42) which delimits within the second lubricant reservoir (22) a lubricant accumulation zone (44) and a lubricant circulation zone (46).

7. Powertrain (1) according to claim 6, wherein the additional branch (26) of the lubricant circuit (18) opens into the lubricant circulation zone (46).

8. Powertrain (1) according to any one of claims 1 to 7 in combination with claim 6, wherein the second lubricant reservoir (22) includes a vent (48) for venting the circulation area (46).

9. Powertrain (1) according to any one of claims 1 to 8 in combination with claim 6, comprising a bypass channel (68) having a first end (70) open into the circulation area of ​​the second lubricant reservoir (22) and a second end (72) connected to the lubricant circuit (18) between the first lubricant reservoir (20) and the pump (34).

10. Motorized vehicle, comprising a powertrain (1) equipped with a lubrication device (16) according to any one of claims 1 to 9.

11. Motorized vehicle according to claim 10, wherein the second lubricant reservoir (22) is arranged above the first lubricant reservoir (20) in a direction perpendicular to the ground on which the vehicle rests.