Oil recovery device for a gearbox

Abstract

The invention relates to a recovery device (10) for recovering oil intended to be arranged within a gearbox (2) lubricated by oil, such a gearbox (2) comprising an electric machine (40) that is cooled and / or lubricated by the lubricating oil of such a gearbox (2), the recovery device (10) comprising a settling tank (20) for settling the oil, the settling tank (20) comprising at least one discharge port for discharging the oil so as to avoid an overflow of oil from the settling tank (20).

Description

[0001] DESCRIPTION

[0002] TITLE: Gearbox oil recovery device.

[0003] Technical field of the invention

[0004] The invention relates to an oil recovery device intended to be arranged within a gearbox. The invention also relates to a gearbox comprising such an oil recovery device. The invention also relates to a powertrain comprising such a gearbox or such an oil recovery device. The invention also relates to a vehicle comprising such a powertrain or such a gearbox or such an oil recovery device.

[0005] State of the prior art

[0006] A vehicle, particularly an electric or hybrid vehicle, typically includes an oil-lubricated gearbox. Such a gearbox typically accommodates an electric machine. Such an electric machine requires cooling and lubrication with oil. To ensure cooling and lubrication of the electric machine, oil is injected into the electric machine. A shaft of such an electric machine rotates at a very high speed, for example, around 18,000 rpm. To optimize cooling and / or lubrication, the injected oil flow rate is high, for example, around 6 L / min.

[0007] However, such a rotational speed of the electric machine shaft combined with such an oil flow rate results in the creation of a significant volume of foam in the oil. However, oil in the foam state does not have as high a lubricating power as oil in the liquid state. In particular, air bubbles have a different density from oil and degrade the heat dissipation properties of the oil. This results in a risk of degradation and / or potential failure of the surfaces of the gears and / or bearings and / or bearings of the gearbox insufficiently lubricated and / or cooled by an oil containing foam.

[0008] Such a situation is not acceptable.

[0009] Presentation of the invention

[0010] The aim of the invention is to provide an oil recovery device which overcomes the above drawbacks. In particular, the invention proposes an oil recovery device which is easy to manufacture and to install within a gearbox.

[0011] Summary of the invention

[0012] To achieve this objective, the invention relates to an oil recovery device intended to be arranged within an oil-lubricated gearbox, such a gearbox comprising an electrical machine cooled and / or lubricated by the lubricating oil of such a gearbox, the recovery device comprising an oil settling tank, the settling tank comprising at least one oil discharge orifice so as to prevent oil from overflowing from the settling tank.

[0013] The recovery device may comprise at least one deflector intended to direct oil projections from such an electrical machine towards the settling tank.

[0014] The recovery device may be made of plastic and / or composite material.

[0015] The invention also relates to an oil-lubricated gearbox, the gearbox comprising an electrical machine cooled and / or lubricated by the gearbox lubricating oil, the gearbox comprising an oil recovery device as defined previously, the at least one discharge orifice being arranged at the bottom of the settling tank so as to discharge oil free of foam.

[0016] The oil settling tank can be arranged under the electric machine.

[0017] The electric machine may include:

[0018] - a stator,

[0019] - a casing fixed relative to the gearbox, the casing being able to be intended in particular to hold the stator in position,

[0020] - a rotor,

[0021] - a shaft ensuring the rotation of the rotor relative to the stator, the shaft possibly having an axial duct, in particular a non-opening axial duct, and at least one radial duct opening into the axial duct so that the oil travels through the axial duct and is projected radially via the at least one radial duct to lubricate and / or cool the electrical machine.

[0022] The casing of the electric machine may comprise at least one opening in its lower part so as to promote oil flow from the internal walls of the casing towards the settling tank.

[0023] The gearbox may comprise a first outer shell and a second outer shell, the first and second outer shells being intended to be fixed to one another, the settling tank being able to be fixed to the first shell and / or to the second shell, in particular by means of a screw and / or a centering pin and / or a holding pin.

[0024] The at least one deflector may be fixed to the first shell and / or to the second shell, in particular by means of a screw and / or a centering pin and / or a holding pin. The gearbox may comprise a first outer shell and a second outer shell, the first and second outer shells being intended to be fixed to one another, the settling tank being able to be held in position within the gearbox by wedging between the first shell and the second shell.

[0025] The gearbox may comprise a first outer shell and a second outer shell, the first and second outer shells being intended to be fixed to each other, the at least one deflector being able to be maintained within the gearbox by being wedged between the first shell and the second shell.

[0026] The invention also relates to a powertrain, in particular for a motor vehicle, the powertrain comprising a gearbox as defined previously or an oil recovery device as defined previously.

[0027] The invention also relates to a vehicle, in particular a motor vehicle, comprising a gearbox as defined previously or an oil recovery device as defined previously or a powertrain as defined previously.

[0028] Presentation of figures

[0029] These objects, characteristics and advantages of the present invention will be explained in detail in the following description of an embodiment of a recovery device given without limitation in relation to the attached figures among which:

[0030] Figure 1 is a schematic view of a motor vehicle according to one embodiment of the invention.

[0031] Figure 2 is a partial perspective view of a gearbox according to one embodiment of the invention. Figure 3 is another partial perspective view of the gearbox according to the embodiment of the invention.

[0032] Figure 4 is a partial sectional view, along a plane P perpendicular to an axis A, of the gearbox according to the embodiment of the invention.

[0033] Figure 5 is a partial sectional view, along a plane B passing through the axis A, of the gearbox according to the embodiment of the invention. Figure 6 is a perspective view of an electric machine of a gearbox according to the embodiment.

[0034] Figure 7 is a perspective view of a baffle of an oil recovery device according to one embodiment.

[0035] Figure 8 is a perspective view of a settling tank of the oil recovery device according to the embodiment.

[0036] Figure 9 is another perspective view of the settling tank of the oil recovery device according to the embodiment.

[0037] Detailed description

[0038] The direction in which a vehicle, especially a motor vehicle, moves in a straight line is defined as the longitudinal direction X. By convention, the direction perpendicular to the longitudinal direction, located in a plane parallel to the ground, is called the transverse direction Y. The third direction, perpendicular to the other two, is called the vertical direction Z. Thus, we use a direct XYZ reference frame in which X is the longitudinal direction in the front-rear direction of the vehicle, therefore directed towards the rear, Y is the transverse direction directed towards the right and Z is the vertical direction directed upwards. The forward direction corresponds to the direction in which the vehicle usually moves in the longitudinal direction and is opposite to the rear direction.

[0039] Figure 1 schematically illustrates a vehicle 1, preferably a motor vehicle. The vehicle 1 comprises a powertrain 9. The powertrain 9 comprises, for example, an electric motor and / or a heat engine. The powertrain 9 or the vehicle 1 comprises a gearbox 2. The gearbox 2 comprises an electric machine 40. The gearbox 2 is lubricated by oil. The electric machine 40 is also lubricated by oil. Advantageously, the lubricating oil of the gearbox 2 is used to lubricate and / or cool the electric machine 40 as will be described later.

[0040] As illustrated in Figures 2, 3 and 4 in particular, the gearbox 2 comprises a lower part 7. By “lower part” is meant an area extending at the lowest points in the vertical direction Z of the gearbox, the gearbox being installed in the vehicle parked on a surface substantially parallel to the XY plane.

[0041] As illustrated in Figures 2 and 3, the gearbox 2 comprises for example a first outer shell or casing or half-casing 3 and a second outer shell or casing or half-casing 4. The first and second outer shells 3, 4 are fixed to each other, or relative to each other. Preferably, a fixing means 8 is provided for assembling the shells 3, 4 together. The fixing means 8 comprises for example screw-nut systems of the bolt type, or screws passing through one shell and cooperating in threads made in the other shell or studs screwed into one shell, passing through the other shell and nuts cooperating with these studs.

[0042] The vehicle 1, or the powertrain 9, or the gearbox 2, comprises an oil recovery device 10.

[0043] The oil recovery device 10 is intended to be arranged within the gearbox 2. As a reminder, the gearbox 2 is lubricated by oil and comprises an electric machine 40 cooled and / or lubricated by the lubricating oil of the gearbox 2. The electric machine 40 is for example sandwiched between the two external shells 3, 4 as illustrated in FIG. 5.

[0044] As illustrated in particular in Figure 2, the recovery device 10 comprises an oil settling and recovery tank 20. Preferably, as illustrated in Figures 3, 4 and 5, the settling tank 20 comprises at least one oil discharge orifice 21 so as to prevent oil from overflowing from the settling tank 20. In the illustrated embodiment, three orifices 21 are provided. Alternatively, one, two, or more than three orifices may also be suitable. For example, as illustrated, the orifices 21 are provided in conduits or tubes or pipes extending from a bottom 22 of the settling tank 20. For example, the section of the orifices is circular. Alternatively, a single orifice is provided within a chute. For example, the section of such an orifice is square or rectangular or of another shape.Thus, advantageously, the orifice(s) 21 for discharging the oil from the settling tank are arranged at the bottom of the settling tank 20 so as to discharge oil free of foam as will be explained later. Preferably, the orifice(s) are located at the lowest points of the settling tank so as to allow discharge of the oil without residual oil volume within a cavity of the settling tank. In any event, the orifice(s) 21 for extracting the oil are arranged below a predefined lower level N of the oil in the foam state (Figure 4).

[0045] As illustrated in particular in Figures 2, 3 and 4, the oil settling tank 20 is arranged under the electric machine 40 or at least partly under the electric machine 40.

[0046] Preferably, the settling tank is a tank or reservoir or oil reserve of the gearbox 2. For example, in the case where the first and second external shells 3, 4 are fixed to each other, the settling tank 20 is held in position within the gearbox 2 by wedging or blocking or pinching between the first shell 3 and the second shell 4.

[0047] Alternatively, the settling tank 20 is fixed to the first shell 3 and / or to the second shell 4, for example by means of a screw 5 and / or a centering pin and / or a holding pin. If one or more screws 5 are used, ears or extensions 23 are preferably made of the same material as the settling tank, as illustrated in FIGS. 8 and 9 in particular.

[0048] For example, as illustrated in Figures 2, 3, 4 and 5, the oil recovery device 10 also comprises at least one deflector 30. The deflector 30 is intended to direct oil projections coming in particular from the electric machine 40 towards the settling tank 20. Alternatively, several deflectors are arranged within the gearbox 2 (variant not illustrated).

[0049] For example, in the case where the first and second external shells 3, 4 are fixed to each other, the deflector(s) 30 are held within the gearbox 2 by wedging or blocking or pinching between the first shell 3 and the second shell 4.

[0050] Preferably, the deflector 30 is fixed to the first shell 3. Alternatively, the deflector 30 is fixed to the second shell 4. Alternatively, the deflector 30 is fixed to both shells 3, 4. For example, the fixing to one shell or to both shells is ensured by means of one or more screws 6 and / or one or more centering pins 6' and / or one or more holding pins. If one or more pins are used, such pins are preferably made of the same material as the deflector, as illustrated in FIG. 7. In any case, the container 20 and the deflector 30 are obtained from a material with which it is easy to obtain complex shapes. The container 20 and the deflector 30 are held in position within the casings 3, 4 once the gearbox is closed after assembly.

[0051] As illustrated in Figure 5, the electrical machine 40 comprises for example a stator 41 and a casing 50 fixed relative to the gearbox 2. Preferably, the casing 50 comprises two parts or shells or half-casings 54, 55 which pinch the stator 41 between them to hold it in position. Thus, the casing 50 is for example intended to hold the stator 41 in position. The electrical machine also comprises a rotor 43. The electrical machine also comprises a shaft 44 of axis A ensuring the rotation of the rotor 43 relative to the stator 41 around or substantially around the axis A. The shaft 44 comprises an axial conduit 45, or axial bore, preferably of circular section. Advantageously, the axial conduit 45 is non-opening.The shaft 44 further comprises at least one radial duct 46 opening into the axial duct 45 so that the oil travels through the axial duct 45 and is projected radially via the radial duct(s) 46 to lubricate and / or cool the electrical machine 40. Note that the electrical machine 40 preferably comprises a tapping or supply or duct or oil inlet pipe 42 intended to bring a flow of oil into the axial duct 45. Preferably, the outlet of the tapping 42 corresponds to or extends opposite or opens into the axial duct 45.

[0052] As illustrated in particular in Figures 5 and 6, the casing 50 of the electrical machine 40 comprises at least one opening 51 in a lower part 52. Preferably, as illustrated in Figure 6, each half-casing or flange 54, 55 comprises at least one opening 51. Advantageously, the openings 51 or orifices are provided at the lowest points of the half-casings 54, 55. In any case, the openings 51 allow the oil to be evacuated by trickling from the internal walls 53 of the casing 50. This oil evacuation is done by gravity towards the settling tank 20 arranged under the openings 51.

[0053] Advantageously, the oil recovery device is made of plastic and / or composite material. Thus, the settling tank and / or the deflector(s) are made of plastic and / or composite material.

[0054] Alternatively, the deflector and the settling tank form a single piece by being integrally formed together. Alternatively, the deflector(s) are attached to the settling tank so as to form a single piece.

[0055] As illustrated in particular in Figure 4, the settling tank 20 recovers a large volume of oil containing foam. This foam is produced, and possibly projected, by the rotating electrical machine due to its high rotation and / or the high flow rate of injected oil. In addition to the walls of the shells 3, 4, the additional deflector 30 redirects the oil projections towards the tank 20. Preferably, a projecting rib 11 provided on the second shell 4 (Figures 3 and 4) ensures continuity, or directs, or promotes the flow of the oil projections between this casing 4 of the box 2 and the deflector 30. More projecting shapes or cavities to control the gravitational runoff of the oil can also be provided. For example, as illustrated in Figures 2, 3 and 7, a recess 31 provided on the deflector 30 facilitates the nesting or association or complementarity of shapes between the deflector 30 and the casing 3.

[0056] Thus, the oil projections, in particular foamy ones, are channeled and redirected towards the settling tank 20. The settling tank fills. More precisely, the foam rises in suspension above the oil layer. In other words, the foam floats in the upper part of the oil layer. Advantageously, the volume created within the settling tank 20 is a calm zone, in particular an area not disturbed by the rotating shaft(s) of the gearbox. Advantageously, the oil and the foam within the receiving cavity of the settling tank 20 are not impacted by the movements of the shafts and / or pinions and / or bearings of the rest of the gearbox.

[0057] Due to the presence of the orifices 21, the oil flows from the tank 20. The orifices being arranged at the bottom, it is only oil purged of its foam, that is to say without foam, which is evacuated. Note that the evacuation orifices can be arranged above the lowest level of the settling tank as long as they are below the lower level N of the foam illustrated in Figure 4.

[0058] For example, a cavity extends between the level of the discharge orifice(s) 21 and the bottom of the settling tank so as to store residues, such as filings and / or other waste present in the decanted liquid oil. This prevents these residues from being absorbed by a pump and reinjected into the shaft 44. For example, a means for capturing the residues is provided at the bottom of such a cavity, for example a magnetic capture means.

[0059] It should be noted that the volume of the settling tank 20 is defined to be capable of recovering the oil dripping from the electric machine, while containing a volume of foam in the upper part without overflow. The sections of the extractions 21 are sized accordingly to avoid any overflow of the tank 20. In addition, the conduits comprising the orifices 21, if applicable, have a short length. Indeed, it is appropriate for the orifices 21 to be positioned close to the oil layer in order to prevent the flow of oil leaving the settling tank 20 from generating foam again. Thanks to the oil recovery device, the gearbox 2 and / or the electric machine 40 are not lubricated and / or cooled by oil in the foam state. Only liquid oil is reinjected into the tapping 42.In other words, the oil is free of foam to ensure the cooling and / or lubrication of the electrical machine via axial injection into the rotating shaft 44 of the electrical machine 40 (via the axial conduit 45) and diffused radially via the radial orifices or conduits 46 provided in the shaft. This results in optimal lubrication and / or cooling. Thus, the creation of foam in the oil due to the very high rotation speed of the shaft 44, for example of the order of 18,000 rpm, and / or the high flow rate of the injected oil, for example of the order of 6 L / min, is not harmful. Indeed, the oil falls by gravity, in particular thanks to the deflector 30, into the settling tank 20 which makes it possible to separate the oil in the foam state from the oil in the liquid state. Since HM oil foam is lighter than HL liquid oil, the foam remains and stagnates at the top of the tank.Thus, the oil containing foam is not discharged through one of the discharge orifices 21 of the tank 20 provided at the bottom, or substantially at the bottom, of the settling tank. In other words, the oil discharged from the settling tank is decanted, that is to say free of foam, so that this oil intended to be reinjected at the level of the tapping 42 is in its liquid state. As a result, its lubricating and / or cooling power is optimal for the electrical machine 40 arranged inside the casing 50.

[0060] In other words, the generation of foam in the oil does not penalize the electric machine. The creation of foam, which is a phenomenon due to air retention in the oil that is excessively agitated in a non-vacuum environment, is not stopped. Indeed, the foam is created by the high rotational speed of the electric machine and the high flow rate of the oil passing through its shaft as mentioned above. The solution thus aims to decant enough oil to have liquid oil, without foam, to supply the shaft of the electric machine so as to optimally cool and / or lubricate the electric machine. The oil injected into the shaft 44 is in the liquid state, which ensures the characteristics of the oil both in terms of lubrication and in terms of cooling (removal of calories from elements receiving oil).

[0061] Preferably, a pumping means (not shown) pumps oil, for example at the outlet of an orifice, or orifices 21, that is to say at the bottom or at the level of the liquid oil layer HL to raise it up to the tapping 42 located further up the gearbox preferably. More precisely, as illustrated in Figure 5, the tapping 42 makes it possible to inject oil through the casing 3, directly or substantially directly into the bore 45 of the hollow shaft 44. In particular thanks to the high rotational speed of the electric machine 40 (for example of the order of 18000 rpm) and to the radial holes or conduits 46 in the shaft 44, the parts requiring cooling and / or lubrication, in particular the bearings, receive oil. This therefore results in the lubrication and cooling of these elements.Under the effect of the rotation speed, and / or after cooling and lubrication of the electric machine, the oil is projected towards the inside of the gearbox, or falls directly into the water table or tank by trickling, in particular along the internal walls of the casings 3, 4.

[0062] The solution also makes it possible to store air bubbles that have a different density from the oil while waiting for the oil to reform to its liquid state. This prevents the air bubbles from being conveyed to the elements to be cooled or lubricated while their heat dissipation capacity is lower than that of the oil. This then avoids any risk of degradation and / or potential failure of the surfaces of elements such as, for example, gears or bearings of the gearbox. The deflector(s) 30 make it possible, for example, to partition and / or separate the electric machine from the rest of the gearbox in order to direct the oil projections towards the settling tank 20. These partitions are designed according to the internal architecture of the gearbox and / or according to the architectural constraints of the gearbox. Alternatively, these partitions are provided directly in the walls of the casings 3, 4.

[0063] Thus, the recovery device 10 makes it possible to overcome a disadvantage of an electrical machine arranged within a gearbox, in particular an electrical machine lubricated and / or cooled by the same layer of oil as the rest of the gearbox. The solution is inexpensive, in particular due to the possibility of manufacturing the recovery device in plastic for example. This type of material makes it easy to add ribs, walls, complex shapes to adapt to the internal shapes of the shells 3, 4 of the gearbox which are generally made from castings. Optionally, at least one shell 3, 4 comprises at least one rib 11 making it possible to maximize runoff and / or to allow nesting of the parts.

[0064] The solution also makes it possible to resolve the problem of excessive foam generation resulting from oil mixing in all types of gearbox. For this, as seen previously, partitioning around the areas promoting foam generation can be provided, for example at the gearbox housing, for example via additional ribs in the casting, or the addition of additional partitions. Alternatively, or in addition, other shapes promoting the guidance and recovery of the oil by gravity flow are provided, in particular at the deflector. These added parts are maintained within the assembled, closed gearbox, for example between the external shells 3, 4. Note that this decanted oil is possibly raised to be conveyed to elements of the gearbox requiring lubrication.Furthermore, this oil may flow from the orifices 21 to another tank or receptacle or casing receiving a pinion or a pulley or a crown, for example a differential crown, so that the decanted oil lubricates the gearbox by splashing such a crown in the oil.

[0065] In the case of a single-piece deflector and settling tank in particular (variant not shown), positioning within the gearbox is easier and faster.

[0066] As a note, the solution therefore achieves the desired objective of providing an oil recovery device preventing the injection of oil foam into the lubrication and / or cooling circuit(s) of the gearbox and the electric machine and has the following advantages:

[0067] - it can be used in gearboxes intended for other types of vehicles, such as agricultural machinery, construction machinery, boats, or other equipment.

[0068] - the shape of the oil recovery device can be easily adapted to the internal configuration of any type of gearbox, in particular due to its material.

Claims

CLAIMS 1. Oil recovery device (10) intended to be arranged within a gearbox (2) lubricated by oil, such a gearbox (2) comprising an electric machine (40) cooled and / or lubricated by the lubricating oil of such a gearbox (2), characterized in that the recovery device (10) comprises an oil settling tank (20), the settling tank (20) comprising at least one oil discharge orifice (21) so as to prevent oil from overflowing from the settling tank (20).

2. Oil recovery device (10) according to the preceding claim, characterized in that the recovery device (10) comprises at least one deflector (30) intended to direct oil projections from such an electrical machine (40) towards the settling tank (20).

3. Oil recovery device (10) according to one of the preceding claims, characterized in that the recovery device (10) is made of plastic material and / or composite material.

4. Gearbox (2) lubricated by oil, the gearbox (2) comprising an electric machine (40) cooled and / or lubricated by the lubricating oil of the gearbox (3), characterized in that the gearbox (2) comprises an oil recovery device (10) according to one of the preceding claims, the at least one discharge orifice (21) being arranged at the bottom of the settling tank (20) so as to discharge oil free of foam.

5. Gearbox (2) according to the preceding claim, characterized in that the oil settling tank (20) is arranged under the electric machine (40).

6. Gearbox (2) according to one of claims 4 or 5, characterized in that the electric machine (40) comprises: - a stator (41), - a casing (50) fixed relative to the gearbox (2), the casing (50) being intended in particular to hold the stator (41) in position, - a rotor (43), - a shaft (44) ensuring the rotation of the rotor (43) relative to the stator (41), the shaft (44) having an axial conduit (45), in particular an axial conduit (45) non-opening, and at least one radial conduit (46) opening into the axial conduit (45) so that the oil travels through the axial conduit (45) and is projected radially via the at least one radial conduit (46) for lubricating and / or cooling the electric machine (40).

7. Gearbox (2) according to the preceding claim, characterized in that the casing (50) of the electric machine (40) comprises at least one opening (51) in its lower part (52) so as to promote oil flow from the internal walls (53) of the casing (50) towards the settling tank (20).

8. Gearbox (2) according to one of claims 4 to 7, the gearbox (2) comprising a first outer shell (3) and a second outer shell (4), the first and second outer shells (3, 4) being intended to be fixed to one another, characterized in that the settling tank (20) is fixed to the first shell (3) and / or to the second shell (4), in particular by means of a screw (5) and / or a centering pin and / or a holding pin.

9. Gearbox (2) according to the preceding claim in combination with claim 2, characterized in that the at least one deflector (30) is fixed to the first shell (3) and / or to the second shell (4), in particular by means of a screw (6) and / or a centering pin (6') and / or a holding pin.

10. Gearbox (2) according to one of claims 4 to 7, the gearbox (2) comprising a first outer shell (3) and a second outer shell (4), the first and second outer shells (3, 4) being intended to be fixed to one another, characterized in that the settling tank (20) is held in position within the gearbox (2) by wedging between the first shell (3) and the second shell (4). . Gearbox (2) according to one of claims 4 to 7 in combination with claim 2, the gearbox (2) comprising a first outer shell (3) and a second outer shell (4), the first and second outer shells (3, 4) being intended to be fixed to one another, characterized in that the at least one deflector (30) is held within the gearbox (2) by wedging between the first shell (3) and the second shell (4).. Powertrain (9), in particular for a motor vehicle (1), characterized in that the powertrain (9) comprises a gearbox (2) according to one of claims 4 to 11 or an oil recovery device (10) according to one of claims 1 to 3. .Vehicle, in particular a motor vehicle (1), characterized in that it comprises a gearbox (2) according to one of claims 4 to 11 or an oil recovery device (10) according to one of claims 1 to 3 or a powertrain (9) according to the preceding claim.

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