Reduction gear for a powertrain

Abstract

The invention relates to a speed reduction gear (1) for a powertrain, comprising: - a reduction device comprising a first toothed wheel (122) able to be rotated about a first axis of rotation (X), the first toothed wheel (122) comprising an annular groove (11) located about the first axis of rotation (X) on a flank of the first toothed wheel (122), - a deflector (20) comprising a ramp (25) for guiding a lubricant, a portion of the ramp being located inside the annular groove (11) of the first toothed wheel (122).

Description

DESCRIPTION TITLE: REDUCER FOR POWERTRAIN TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates, in general, to the technical field of speed reducers, in particular their lubrication means. STATE OF THE PRIOR ART

[0002] To lubricate a speed reduction device, in particular bearings, gears (...), reducers may be equipped with a pump that circulates a lubricant such as oil in a lubrication circuit configured to reach different specific areas to be lubricated. These reducer lubrication devices are called "active".

[0003] There are also so-called "passive" lubrication devices, i.e. without a pump, in which ramps are formed within the casing to encourage the lubricant to rise from the bottom of the reducer to the top and thus disperse the lubricant in different areas of the reducer.

[0004] However, these passive lubrication solutions are not entirely satisfactory and the return of lubricant from the bottom to the top of the reducer is sometimes not sufficient, particularly when elements of the reduction device, for example a transmission shaft carrying toothed wheels, prevent the return of lubricant to the top of the reducer. STATEMENT OF THE INVENTION The invention aims to remedy this problem by proposing a speed reducer for a powertrain, comprising: a reduction device comprising a first toothed wheel capable of being driven in rotation around a first axis of rotation, the first toothed wheel comprising an annular groove arranged around the first axis of rotation on a flank of the first toothed wheel, a deflector comprising a ramp capable of guiding a lubricant, a portion of the ramp being arranged inside the annular groove of the first toothed wheel.

[0005] Thus, by cooperating with the deflector ramp, the annular groove of the gear wheel is used to centrifugally raise lubricant. In fact, the lubricant can be more efficiently transferred from a lower portion of the first gear wheel to a higher portion of the first gear wheel. The lubrication of the reducer is thus improved.

[0006] The reducer may also include at least one of the following characteristics:

[0007] - The annular groove is axially open on one side of the first gear wheel.

[0008] - The first gear wheel comprises a hub, a peripheral toothed band arranged radially outside the hub (relative to the axis of rotation X), and a wheel web connecting the hub and the peripheral toothed band.

[0009] - The annular groove of the first toothed wheel is delimited on one side of the first toothed wheel by the hub, the wheel disc, and the peripheral toothed band.

[0010] - The ramp comprises a main track and an axial protrusion extending the main track and projecting axially from the main track, the axial protrusion being arranged partly or wholly within the annular groove of the first gear.

[0011] - The main track is arranged entirely outside the annular groove of the first gear wheel.

[0012] - The reduction device comprises a second toothed wheel capable of being driven in rotation around a second axis of rotation parallel to the first axis of rotation, the second toothed wheel comprising a peripheral toothed band arranged radially, relative to this second axis, opposite the main track of the ramp.

[0013] - The diameter of the second gear wheel is greater than the diameter of the first gear wheel, for example between 1.5 and 4 times greater, and the first axis of rotation is arranged, when the reducer is in a position corresponding to that taken when it is mounted on a vehicle parked horizontally, above the second axis.

[0014] - A horizontal plane tangent to the first wheel and located below the first axis is arranged higher than a horizontal plane tangent to the second wheel and located below the second axis.

[0015] - The first wheel is arranged above the oil level, in particular below the nominal level NN.

[0016] - The first gear wheel and the second gear wheel are axially offset from each other.

[0017] - In particular, if we consider on the one hand a first plane passing through the first axis of rotation and the second axis of rotation, and on the other hand a second plane corresponding to the horizontal plane passing through the second axis of rotation, an angle between 10 and 45 degrees separates the first plane and the second plane.

[0018] - The ramp, including the main ramp track, is: - arranged to cover a portion of the second toothed wheel, along an angular sector limited relative to the second axis of rotation and - spaced from the teeth of the second gear wheel so as to allow lubricant to flow between the ramp and the second gear wheel.

[0019] - The angular sector can be between 20 and 90 degrees, for example between 30 and 50 degrees.

[0020] - The main track is spaced from the second gear of a first set.

[0021] - The second gear wheel is a drive wheel of a differential drive device.

[0022] - The main track has a shape that matches the peripheral toothed band of the second toothed wheel covered by the ramp.

[0023] - The first set is between 2 and 5mm.

[0024] - The teeth of the second gear wheel are inclined, for example helical, the inclination of the teeth being such that the lubricant is directed axially towards the side of the first gear wheel.

[0025] - The deflector comprises a screen arranged on at least one side of the ramp so as to prevent the lubricant from falling on that side of the ramp.

[0026] - According to one variant, the screen is formed on the casing.

[0027] - The screen extends in a plane substantially perpendicular to the second axis of rotation.

[0028] - The screen is located on the same side of the ramp as the first cogwheel.

[0029] - the screen is located on the same side of the main ramp track as the first gear wheel. Such a screen improves the lubrication of the reducer. In fact, the screen directs the lubricant towards the flank of the first gear wheel. The rise of the lubricant by centrifugation is thus encouraged and the lubricant can be more efficiently transferred from a lower portion of the first gear wheel to a higher portion of the first gear wheel.

[0030] - The screen and the axial protrusion are located on the same side of the main ramp track.

[0031] - The axial protrusion comprises a track extending in a plane parallel to the first axis of rotation.

[0032] - Viewed in the plane of the axial protrusion, the annular groove has a cross-section of complementary shape to the edge of the axial protrusion. In other words, the axial protrusion and the annular groove are axially nested within each other.

[0033] - The annular groove is delimited by walls and a second clearance separates the axial protrusion from the walls of the annular groove. The second clearance may be greater in the axial direction than in the radial direction.

[0034] - According to a variant, the second clearance is substantially constant along the walls of the annular groove.

[0035] - The reducer comprises a casing enclosing the reduction device, the deflector being manufactured in a separate part from the casing, for example in plastic, in particular by an injection molding process.

[0036] - The deflector comprises a mounting portion comprising a plurality of fixing elements cooperating with complementary fixing elements arranged in the gearbox housing.

[0037] - The reducer housing comprises a first part and a second part assembled to each other by enclosing the reduction device, the fixing elements are arranged so that at least one fixing element is fixed on the first part of the housing and at least one fixing element is fixed on the second part of the housing.

[0038] - The mounting portion provided with a plate extending substantially in a plane perpendicular to the first axis of rotation and the fixing elements are arranged on either side of the plate.

[0039] - The fixing elements are mounting studs and the complementary fixing elements of the housing are mounting housings.

[0040] - The fixing studs protrude from the plate.

[0041] - The reducer comprises a first shaft on which the first toothed wheel is mounted.

[0042] The reducer comprises a first bearing arranged to guide in rotation, along the first axis X, the first shaft, the first bearing being mounted in a first housing of the casing, and in which an end zone of the ramp of the deflector is arranged: - axially along the first axis of rotation, between the first toothed wheel and the first bearing, - radially relative to the first axis of rotation, closer to the first axis of rotation than the radially outer periphery of the first bearing, - radially closer to the first axis of rotation than the radially outer periphery of the first gear wheel.

[0043] - The reduction device comprises a third toothed wheel driven in rotation about the first axis of rotation and meshing with the second toothed wheel, the second toothed wheel and the third toothed wheel being arranged on the same plane, the third toothed wheel being arranged beyond an upper end of the deflector ramp.

[0044] - The outer diameter of the third gear wheel is less than the outer diameter of the annular groove.

[0045] - The third gear wheel is spaced from the ramp by a distance of less than 3 cm, preferably less than 2 cm.

[0046] - The third gear wheel is an output wheel of the first shaft.

[0047] - The first gear wheel is an input wheel of the first shaft.

[0048] - The deflector is manufactured in a separate part from the casing, for example from plastic, in particular using an injection molding process.

[0049] - According to one variant, the deflector is formed in one piece with the first part of the casing.

[0050] - Seen in a plane perpendicular to the first axis of rotation, the deflector ramp has a shape which has a circumferential (or tangential) component which increases as it approaches the first axis of rotation.

[0051] - The reduction device comprises an input shaft parallel to the first shaft and a first double reduction stage comprising: - on the one hand, for a first ratio, a first coaxial pinion and integral in rotation with the input shaft as well as a fourth toothed wheel meshing with the first pinion and capable of driving the first shaft in rotation around the first axis of rotation; and - on the other hand, for a second ratio, a second coaxial pinion and integral in rotation with the input shaft as well as the first toothed wheel meshing with the second pinion and capable of driving the first shaft in rotation around the first axis of rotation, the reduction device comprising a speed selection device capable of securing in rotation the first toothed wheel or the fourth toothed wheel with the first shaft.

[0052] Thus, the invention is particularly useful in this two-speed reduction architecture where it is difficult to properly disperse the lubricant. Since the first gear is necessarily rotated when the electric machine is rotating, (regardless of the selected ratio), the lubricant can be properly dispersed regardless of the selected ratio.

[0053] The invention also relates to a powertrain comprising an electric machine and a reducer as described above. Where appropriate, the electric machine comprises a rotor shaft which may be coaxial and integral in rotation with the input shaft of the reducer.

[0054] Other characteristics and advantages of the invention are highlighted by the following description of non-limiting examples of embodiments of the different aspects of the invention. BRIEF DESCRIPTION OF THE FIGURES Other characteristics and advantages of the invention will emerge on reading the description which follows, with reference to the appended figures, which illustrate: Figure 1: a side view of a reducer, according to a first embodiment, shown without the casing. Figure 2: A perspective view of the reducer of Figure 1, shown without the casing and without the oil receiver. Figure 3: A perspective view of the deflector of the first embodiment, in which the housing and the differential wheel have been removed. Figure 4: a view schematically showing the mounting of the deflector of the first embodiment in the casing. Figure 5: a view of a part of the casing cooperating with the deflector, according to the first embodiment. Figure 6: A view illustrating the cooperation between the protrusion of the deflector and the annular groove of the driven wheel, according to the first embodiment. Figure 7: a partial side view of a deflector according to a second embodiment. Figure 8: A perspective view of a deflector according to a third embodiment. Figure 9: a perspective view of a deflector and the bottom of a casing according to a fourth embodiment. DETAILED DESCRIPTION OF AN EMBODIMENT

[0055] In the following description, the first axis of rotation is called the X axis of rotation, the second axis of rotation is called the Y axis of rotation, and the third axis of rotation is called the Z axis of rotation.

[0056] In the description and the claims, the terms "external" and "internal" as well as the orientations "axial" and "radial" will be used to designate, according to the definitions given in the description, elements of the transmission system. By convention, the "axial" orientation relates to the reference axes X, Y or Z or to directions parallel to these axes, and the "radial" orientation is directed orthogonally to the reference axes X, Y and Z. A "radially internal" element is located closer to the reference axis than a "radially external" element.

[0057] The first shaft mentioned above as well as in the claim set corresponds to the intermediate shaft 120 in the embodiments described below.

[0058] The first gear wheel mentioned above as well as in the claim set corresponds to the driven gear 122 of the second gear in the embodiments described below.

[0059] The second gear wheel mentioned previously as well as in the claim set corresponds to the differential wheel 30 in the embodiments described below.

[0060] The third gear wheel mentioned above as well as in the claim set corresponds to the third pinion 123 in the embodiments described below.

[0061] The fourth gear wheel mentioned previously as well as in the claim set corresponds to the driven gear 121 of the first gear in the embodiments described below.

[0062] The terms "upper", "lower", "top", "bottom", and "bottom" should be considered when viewing the speed reducer in a position / tilt similar to its position when mounted on a vehicle parked horizontally.

[0063] Figure 1 is a simplified side view of a speed reducer 1 (also called a gear reducer) shown without its casing so as to visualize the reduction device. Figure 2 shows the same reducer 1 in perspective, without the casing, and without the oil receiver 40 present in Figure 1.

[0064] In Figure 1, the reducer is shown in a position corresponding to its position when mounted in a vehicle parked on a horizontal plane. It has a relatively low portion and a relatively high portion.

[0065] This reducer includes two gear ratios. It can form the primary powertrain of a vehicle, particularly an electric motor vehicle, or a secondary powertrain. For example, it could be a secondary electric powertrain of a hybrid vehicle, particularly intended for the rear axle of the vehicle.

[0066] Reducer 1 includes: - an input shaft 110 intended to be driven by a motor, in particular an electric machine, around an axis of rotation Z, - a differential drive device 130 (also called differential) comprising a differential wheel 30 and a differential bridge 300 capable of rotating two half-shafts along an axis of rotation Y, - an intermediate shaft 120 movable in rotation around an axis of rotation X, and capable of transmitting a torque between the input shaft 110 and the differential wheel 30.

[0067] The input shaft 111 is capable of being driven coaxially by an electric machine rotor shaft, in particular by means of splines.

[0068] The differential wheel 30 drives the differential bridge 300 in a known manner to rotate around the axis of rotation Y. The differential wheel 30 is the drive wheel of the differential drive device.

[0069] The X, Y and Z axes of rotation are parallel.

[0070] The Y axis of rotation is intended to be located, on the vehicle, towards the front of the vehicle relative to the X axis of rotation. Similarly, the X axis of rotation is intended to be located, on the vehicle, towards the front of the vehicle relative to the Z axis of rotation.

[0071] In other words, the reducer has a front AV part and a rear AR part. The front AV part is intended to be positioned further towards the front of the vehicle than the rear AR part. The differential is therefore positioned towards the front of the reducer and the input shaft towards the rear. Thus, when the vehicle is moving forward, the differential wheel 30 rotates in the direction indicated by the arrow T.

[0072] The diameter of the differential wheel 30 is greater than the diameter of the driven wheel 122 of the second gear, for example between 1.5 and 4 times greater, and the axis of rotation X is arranged, when the reducer is in a position corresponding to that taken when it is mounted on a vehicle parked horizontally, above the axis of rotation Y.

[0073] In particular, if we consider on the one hand a first plane passing through the axis of rotation X and the axis of rotation Y, and on the other hand a second plane corresponding to the horizontal plane passing through the axis of rotation Y, an angle between 10 and 45 degrees separates the first plane and the second plane.

[0074] The reducer 1 comprises a first double reduction stage El between the input shaft 110 and the intermediate shaft 120. The reducer also comprises a second reduction stage E2 between the intermediate shaft 120 and the differential axle 300.

[0075] The first stage of double reduction El includes: - on the one hand, for the first gear, a first pinion 111 integral in rotation with the input shaft 110 relative to the axis of rotation Z as well as a driven wheel 121 meshing with the first pinion 111 and capable of driving the intermediate shaft 120 in rotation around the axis of rotation X; and - on the other hand, for the second gear, a second pinion 112 integral in rotation with the input shaft 110 relative to the axis of rotation Z as well as a driven wheel 122 meshing with the second pinion 112 and capable of driving the intermediate shaft 120 in rotation around the axis of rotation X.

[0076] The names “driven wheel 121 of the first gear” and “driven wheel 122 of the second gear” will be used in the remainder of the description.

[0077] The second reduction stage E2 comprises a third pinion 123 integral in rotation with the intermediate shaft 120 relative to the axis of rotation X as well as the differential wheel 30, rotating around the axis of rotation Y, the differential wheel 30 meshing with the third pinion 123.

[0078] The driven wheel of the second gear 122 and the differential wheel 30 are axially offset from each other.

[0079] The gear ratio change therefore occurs at the first double reduction stage E1 by means of a gear selection device 400. The gear selection device 400 comprises a fork 401 capable of translating parallel to the axis of rotation X. This fork can be moved by a known actuating device not shown. The fork 401 makes it possible to slide a dog clutch sleeve along the axis of rotation X so as to secure the intermediate shaft 120 with the driven wheel 121 of the first gear, or with the driven wheel 122 of the second gear. To do this, the driven wheel 121 of the first gear and the driven wheel 122 of the second gear each comprise a dog clutch toothing arranged around the axis of rotation X capable of cooperating with the dog clutch sleeve.The driven wheel 121 of the first gear and the driven wheel 122 of the second gear are rotatably mounted around the intermediate shaft 120 and the dog clutch sleeve is mounted to rotate with the intermediate shaft 120, for example by means of splines. It is therefore the cooperation between the dog clutch sleeve and the dog clutch teeth of the driven wheel 121 of the first gear, respectively of the driven wheel 122 of the second gear, which makes it possible to rotate with the driven wheel 121 of the first gear, respectively the driven wheel 122 of the second gear, and the intermediate shaft 120 about the axis of rotation X. The dog clutch sleeve comprises, for example, dog clutch teeth at its two axial ends.

[0080] Preferably, the dog clutch sleeve can be kept spaced from the driven wheel 121 of the first gear and the driven wheel 122 of the second gear in a neutral position, for which no torque is transmitted between the input shaft 110 and the intermediate shaft 120 because none of the driven wheels 121 and 122 of the first and second gears cooperates with the dog clutch sleeve. The neutral position corresponds to a disconnection mode. In this mode, the electric machine no longer transmits torque to the two half-shafts, therefore to the wheels in contact with the road, and vice versa.

[0081] The reduction device, in particular the bearings supporting the shafts 110, 120, the meshing between the pinions 111, 112 and the driven wheels 121, 122, the meshing between the pinion 123 and the differential wheel 30 as well as the dog clutch sleeve require lubrication, in particular with oil. The lubrication of the reducer is passive here. In other words, it does not include a pump dedicated to circulating a lubricant within the reducer. The lubrication is based here on the presence of an oil bath at the bottom of the reducer and on the routing of this oil towards the various elements of the reducer to be lubricated (bearings, gears, dog teeth) thanks, in particular, to the projections of oil caused by the rotation of the differential wheel 30, the pinions 111, 112, 123 and the driven wheels 121, 122, and thanks to gravity.

[0082] The term bearing here refers to both plain bearings and rolling bearings.

[0083] When the vehicle is stationary, a lower portion of the differential wheel 30 is immersed in the oil bath. When the vehicle is in motion, the differential wheel 30 rotates around the axis of rotation Y, which allows the oil to be dispersed, in particular to rise as indicated by the arrow F. The oil level at the bottom of the reducer is then lower.

[0084] To improve the passive lubrication of the reducer, a deflector 20 is arranged, in the lower part of the reducer, to promote the rise of the lubricant and a receiving tank 40 is arranged in the upper part so as, on the one hand, to receive the lubricant which has been previously raised and, on the other hand, to redirect the lubricant to different points of the reducer, in particular by gravity.

[0085] The deflector 20 allows the projection of oil to be guided.

[0086] A first embodiment of the deflector and the driven wheel 122 of the second gear with which it cooperates is shown in Figures 3 and 4.

[0087] The toothed wheel 122 of the second gear comprises an annular groove 11 arranged around the axis of rotation X and axially open on one side of the toothed wheel 122 of the second gear. Here, the annular groove 11 is arranged on the right side of the driven wheel 122 of the second gear.

[0088] The driven wheel 122 of the second gear comprises a hub 1223, a peripheral toothed band 1221 arranged radially outside the hub 1223, and a wheel disc 1222 connecting the hub 1223 and the peripheral toothed band 1221.

[0089] The annular groove 11 of the driven wheel 122 is delimited on one side of the driven wheel 122 by the hub 1223, the wheel disc 1222 and the toothed peripheral strip 1221.

[0090] The deflector 20 comprises a ramp 25 capable of guiding the lubricant. A portion of the ramp 25 is arranged inside the annular groove 11 of the driven wheel 122 of the second gear. The ramp is configured to direct the lubricant into the annular groove of the driven wheel 122 of the second gear so that the lubricant is centrifuged by the driven wheel 122 of the second gear and thus redirected towards the top of the reducer.

[0091] The lower edge of the ramp 25 is preferably arranged below the oil level, in particular below the nominal level NN. The nominal level corresponds to the indicative oil level marked on the reducer, when the vehicle is stationary. Otherwise, the nominal level may correspond to the horizontal plane passing through the lower edge of the opening intended for filling / draining the reducer. The driven wheel 122 of the second gear is arranged completely above the nominal oil level.

[0092] The ramp 25 comprises a main track 22 and an axial protrusion 21 extending the main track 22 and projecting axially from the main track 22.

[0093] The axial protrusion 21 is arranged largely inside the annular groove 11 of the driven wheel 122 of the second gear. The main track 22 is arranged entirely outside the annular groove 11 of the driven wheel 122 of the second gear.

[0094] The differential wheel 30 comprises a peripheral toothed band, a part of which is arranged, relative to the axis of rotation Y, radially opposite the main track 22 of the ramp 25.

[0095] The ramp 25 of the deflector, in particular the main track 22 of the ramp 25, is arranged to cover the peripheral toothed band of the differential wheel 30, along an angular sector limited relative to the axis of rotation Y. The angular sector is between 20 and 90 degrees, for example between 30 and 50 degrees.

[0096] In addition, the ramp 25, in particular the main track 22 of the ramp 25, is spaced from the teeth of the differential wheel 30 by a first set 31. This first set can be between 2 and 5 mm.

[0097] The main track 22 advantageously has a shape matching the peripheral toothed band of the differential wheel 30 covered by the ramp. In particular, in a plane perpendicular to the axis of rotation Y, the ramp 25 has the shape of an arc of a circle.

[0098] The deflector 20 further comprises a screen 23 arranged on at least one side of the ramp 25 so as to prevent the lubricant from falling on this side of the ramp 25. The screen 23 is located on the same side of the ramp 25 as the driven wheel 122 of the second gear. The screen 23 and the axial protrusion 21 are located on the same side of the main track 22 of the ramp 25.

[0099] The screen 23 extends in a plane substantially perpendicular to the axis of rotation Y. The screen has the shape of a plate arranged parallel to the differential wheel 30. The screen 23 is arranged axially opposite a portion of the differential wheel 30. The screen thus borders the ramp over at least half of its length.

[0100] The lower edge of the screen 23 can be arranged below the oil level, in particular below the nominal level.

[0101] Here the bottom of screen 23 coincides with the bottom of ramp 25.

[0102] The third pinion 123 is disposed beyond an upper end of the deflector ramp. The outer diameter of the third pinion 123 is less than the outer diameter of the annular groove 11.

[0103] The reducer includes a lubricant such as oil, and when the reducer is in a position corresponding to that taken when mounted on a horizontally parked vehicle, a lower end of the ramp is immersed in the lubricant.

[0104] The deflector 20 also includes a mounting portion 26.

[0105] The mounting portion 26 comprises a plate 27 extending substantially in a plane perpendicular to the axis of rotation X. The plate is preferably arranged in the extension of the screen 23, beyond the ramp 25. In other words, the plate T1 and the screen 23 are arranged on the same plane.

[0106] The mounting portion 26 also comprises a plurality of fixing studs 29 cooperating with housings 63 arranged in the casing 60 of the reducer.

[0107] The fixing studs 29 are arranged on either side of the plate T1. In the embodiment shown in FIG. 3, the deflector comprises four fixing studs, namely two fixing studs 29 arranged on one side of the plate 27 and two other fixing studs 29 arranged on the other side of the plate. The fixing studs 29 protrude from the plate. They extend perpendicular to the plate T1.

[0108] The casing comprises a first part 61 and a second part 62 assembled together and enclosing the reduction device. The first part 61 may also form all or part of the casing of the electric machine.

[0109] The first part 61 comprises two mounting housings 63 cooperating with two fixing studs 29 of the deflector and the second part 62 comprises two other mounting housings 63 cooperating with two other fixing studs 29 of the deflector.

[0110] In another embodiment not shown, the mounting housings are formed on the deflector and the fixing studs are formed on the housing.

[0111] In Figure 4, the mounting of the deflector 20 in the two parts 61 and 62 of the casing 60 is shown schematically.

[0112] The intermediate shaft 120 extends along the axis of rotation X and carries the driven wheel 122 of the second gear.

[0113] A first bearing 66 makes it possible to guide the intermediate shaft 120 in rotation along the axis of rotation X. The first bearing 66 is mounted in a first housing 69 of the first part 61 of the casing 60. The first bearing 66 supports a first end of the intermediate shaft 120.

[0114] A second bearing 67 makes it possible to guide the intermediate shaft 120 in rotation along the rotation axis X. The second bearing 67 is mounted in a second housing of the second part 62 of the casing 60.

[0115] Because it is manufactured in a separate part from the casing 60, it is possible for an end zone 28 of the deflector 20, comprising in particular the axial protrusion 21, to be arranged, radially relative to the first axis of rotation X, closer to the axis of rotation X than the radially external periphery of the first bearing 66.

[0116] The end zone 28 of the deflector is arranged, axially along the first axis X, between the driven wheel 122 of the second gear and the first bearing 66.

[0117] This feature is also visible in Figure 1 in which only the outer ring of the bearing 66, with its outer diameter d66, is shown. It can be seen that the deflector penetrates into a straight axial cylindrical volume centered on the axis of rotation X whose diameter corresponds to the outer diameter d66 of the first bearing 66.

[0118] The end zone 28 of the deflector is arranged, axially along the first axis X, between the driven wheel of the second gear and the first bearing 66.

[0119] As seen previously, due to the cooperation between the axial protrusion and the annular groove of the driven wheel 122 of the second gear, the end zone 28 of the deflector is also arranged, radially, relative to the first axis X, closer to the axis of rotation X than the radially outer periphery of the driven wheel 122 of the second gear.

[0120] In Figure 5, it can be seen that the casing 60 also comprises a complementary ramp 64 arranged in the extension of the ramp 25 of the deflector 20 so that the lubricant is guided from the complementary ramp 64 of the casing 60 to the ramp 25 of the deflector 20.

[0121] It is noted that the complementary ramp 64 is provided with a passage 641 to allow a return of the lubricant to the base of the complementary ramp, in particular by gravity. Thus, the lubricant can fall back to the bottom of a circular housing of the casing corresponding to the location of the differential wheel 30. Preferably, the bottom of the circular housing is the lowest point of the interior volume of the casing.

[0122] The complementary ramp and the passage can be made on both parts 61 and 62 of the casing 60. This is particularly useful when the differential wheel 30 is located in the axial assembly plane of the first part 61 and the second part 62 of the casing 60.

[0123] The baffle is made of plastic in a separate part from the housing, for example using an injection molding process. This allows for different baffle shapes.

[0124] In a different reducer configuration, it could be envisaged that the deflector is formed in one piece with one of the first part or the second part of the casing.

[0125] Returning to the embodiment of Figure 3, it can be seen that the axial protrusion 21 extends substantially in a plane parallel to the axis of rotation X, or even in a plane comprising the axis of rotation X.

[0126] Seen in the plane of the axial protrusion (figure 6), the annular groove 11 has a section of complementary shape to the edge of the axial protrusion (21). In other words, the axial protrusion 21 and the annular groove 11 are nested axially one into the other. A second axial clearance of between 1 and 3 mm may, for example, separate the protrusion 21 and the groove 11. This clearance may be greater in the axial direction than in the radial direction.

[0127] In the embodiment of Figure 6, seen in a plane perpendicular to the axis of rotation X, the ramp 25 of the deflector has a shape whose inclination has a circumferential or tangential component (relative to the axis of rotation X) which increases as it approaches the axis of rotation X. Thus, the oil is gradually guided in a direction approaching the circumferential direction of rotation of the driven wheel 122 of the second gear.

[0128] In the embodiment of Figure 8, the protrusion has a thickness that increases axially, approaching the driven wheel 122 of the second gear. This makes it possible to create an advantageous clearance angle for demolding the deflector.

[0129] In the variant of Figure 9, the casing is devoid of an additional ramp and the ramp comprises a lower portion extending from the bottom of the screen 23 towards the bottom of the casing 60.

[0130] A third clearance j3 separates the bottom of the ramp 25 and the bottom of the casing 60 so as to allow a return of the oil, in particular by gravity, under the lower end of the ramp 25 (in other words under the bottom of the lower portion of the ramp).

[0131] In the various embodiments described here, the deflector allows oil to flow back into a central area of ​​the reducer which is nevertheless cluttered by the intermediate shaft 120, the driven wheels 121, 122 and the pinion 123.

[0132] Naturally, the invention is described in the foregoing by way of example. It is understood that a person skilled in the art is able to carry out different variant embodiments of the invention without departing from the scope of the invention. For example, the invention which has been described here in the context of a two-speed reducer can also be applied to a reducer having a single ratio or more than two ratios.

[0133] It is emphasized that all features, as they emerge for a person skilled in the art from this description, the drawings and the attached claims, even if they have been specifically described only in relation to other specific features, both individually and in any combinations, may be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances make such combinations impossible or meaningless.

Claims

CLAIMS 1. Speed ​​reducer (1) for a powertrain, comprising: - a reduction device comprising a first toothed wheel (122) capable of being driven in rotation around a first axis of rotation (X), the first toothed wheel (122) comprising an annular groove (11) arranged around the first axis of rotation (X) on a flank of the first toothed wheel (122), - a deflector (20) comprising a ramp (25) capable of guiding a lubricant, a portion of the ramp being arranged inside the annular groove (11) of the first toothed wheel (122).

2. Speed ​​reducer (1) according to claim 1 wherein the ramp (25) comprises a main track (22) and an axial protrusion (21) extending the main track (22) and projecting axially from the main track (22), the axial protrusion (21) being arranged partly or entirely inside the annular groove (11) of the first toothed wheel (122).

3. Speed ​​reducer (1) according to claim 2 wherein the reduction device comprises a second toothed wheel (30) capable of being driven in rotation around a second axis of rotation (Y) parallel to the first axis of rotation (X), the second toothed wheel (30) comprising a peripheral toothed band arranged radially, relative to this second axis (Y), opposite the main track of the ramp.

4. Speed ​​reducer (1) according to claim 3 wherein the diameter of the second toothed wheel (30) is greater than the diameter of the first toothed wheel (122), for example between 1.5 and 4 times greater, and the first axis of rotation X is arranged, when the reducer is in a position corresponding to that taken when it is mounted on a vehicle parked horizontally, above the second axis (Y).

5. Speed ​​reducer (1) according to claim 3 or 4 wherein the first toothed wheel (122) and the second toothed wheel (30) are axially offset relative to each other.

6. Speed ​​reducer (1) according to one of claims 3 to 5 in which the second toothed wheel (30) is a drive wheel 30 of a differential drive device 130.

7. Speed ​​reducer (1) according to one of claims 3 to 6 wherein the teeth of the second toothed wheel (30) are inclined, for example helically, the inclination of the teeth being such that the lubricant is directed axially towards the side of the first toothed wheel (122).

8. Speed ​​reducer (1) according to one of claims 3 to 7 wherein the reduction device comprises a third toothed wheel (123) driven in rotation about the first axis of rotation (X) and meshing with the second toothed wheel (30), the second toothed wheel (30) and the third toothed wheel (123) being arranged on the same plane, the third toothed wheel (123) being arranged beyond an upper end of the ramp (25) of the deflector (20).

9. Speed ​​reducer (1) according to one of claims 2 to 8 wherein the deflector (20) comprises a screen (23) arranged on at least one side of the main track (22) of the ramp (25) so as to prevent the lubricant from falling on this side of the ramp.

10. Speed ​​reducer (1) according to claim 9 wherein the screen (23) is located on the same side of the main track (22) of the ramp (25) as the first toothed wheel (122).

11. Speed ​​reducer (1) according to one of claims 2 to 10, in which, seen in the plane of the axial protrusion, the annular groove (11) has a section of complementary shape to the edge of the axial protrusion (21).

12. Speed ​​reducer (1) according to one of the preceding claims in which the reducer comprises a casing (60) enclosing the reduction device, the deflector (20) being manufactured in a part separate from the casing (60), for example in plastic material, in particular by an injection molding process.

13. Speed ​​reducer (1) according to the preceding claim, in which the deflector (20) comprises a mounting portion (26) comprising a plurality of fixing elements (29) cooperating with complementary fixing elements (63) arranged in the casing (60) of the reducer.

14. Speed ​​reducer (1) according to the preceding claim wherein the casing (60) of the reducer comprises a first part (61) and a second part (62) assembled to each other enclosing the reduction device, the fixing elements (29) are arranged so that at least one fixing element (29) is fixed to the first part (61) of the casing and at least one fixing element (29) is fixed to the second part (62) of the casing.

15. Speed ​​reducer (1) according to claim 13 or 14 wherein the fixing elements (29) are mounting studs and the complementary fixing elements (63) of the casing (60) are mounting housings.

16. Speed ​​reducer (1) according to one of claims 12 to 15 wherein the reducer comprises a first shaft (120) on which the first toothed wheel (122) is mounted, as well as a first bearing (66) arranged to guide in rotation, along the first axis of rotation (X), the first shaft (120), the first bearing (66) being mounted in a first housing (69) of the casing (60), and in which an end zone of the ramp (25) of the deflector (20) is arranged: - axially along the first axis of rotation (X), between the first toothed wheel (122) and the first bearing (66), - radially relative to the first axis of rotation (X), closer to the axis of rotation X than the radially outer periphery of the first bearing (66), - radially closer to the axis of rotation X than the radially outer periphery of the first toothed wheel (122).

17. Speed ​​reducer (1) according to one of claims 12 to 15 wherein the reduction device comprises a first shaft (120) on which the first toothed wheel (122) is mounted, an input shaft (110) parallel to the first shaft (120) and a first double reduction stage (El) comprising: - on the one hand, for a first ratio, a first coaxial pinion (111) and integral in rotation with the input shaft (110) as well as a fourth toothed wheel (121) meshing with the first pinion (111) and capable of rotating the first shaft (120) around the first axis of rotation (X); and - on the other hand, for a second ratio, a second pinion (112) coaxial and integral in rotation with the input shaft (110) as well as the first toothed wheel (122) meshing with the second pinion (112) and capable of rotating the first shaft (120) around the first axis of rotation (X), the reduction device comprising a speed selection device capable of rotatingly securing the first toothed wheel (122) or the fourth toothed wheel (121) with the first shaft (120).

18. Speed ​​reducer (1) according to one of the preceding claims wherein the first toothed wheel (122) comprises a hub (1223), a toothed peripheral strip (1221) arranged radially outside the hub (1223), and a wheel web (1222) connecting the hub (1223) and the toothed peripheral strip (1221), the annular groove (11) being delimited on one side of the first toothed wheel (122) by the hub (1223), the wheel web (1222) and the toothed peripheral strip (1221).

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