Reduction gear for a power train

Abstract

The invention relates to a speed reducer (1) for a power train, comprising:-a speed reduction device comprising a first gear (122) rotatable about a first axis of rotation (X), the first gear (122) comprising an annular groove (11) on a side of the first gear (122) about the first axis of rotation (X),-a deflector (20) comprising a ramp (25) for guiding a lubricant, a portion of the ramp portion is located within an annular groove (11) of the first gear (122).

Description

Technical Field

[0001] The present invention generally relates to the technical field of speed reducers, and more particularly to their lubrication devices. Background Art

[0002] To lubricate speed reduction devices, especially bearings, gears, etc., speed reducers can be equipped with pumps that circulate a lubricant, such as oil, in a lubrication circuit configured to reach various specific areas to be lubricated. These devices for lubricating speed reducers are called "active" lubrication devices.

[0003] There are also so-called "passive" lubrication devices, that is, lubrication devices without pumps, in which a ramp portion is formed in the housing to cause the lubricant to rise from the bottom to the top of the speed reducer, thereby dispersing the lubricant to various areas of the speed reducer.

[0004] However, these passive lubrication solutions are not entirely satisfactory, and the rise of the lubricant from the bottom to the top of the speed reducer is sometimes insufficient, especially when elements of the speed reduction device, such as the drive shaft carrying the gears, impede the rise of the lubricant to the top of the speed reducer. Summary of the Invention

[0005] The present invention aims to solve this problem by proposing a speed reducer for a power transmission system, the speed reducer comprising:

[0006] - a speed reduction device including a first gear rotatable about a first axis of rotation, the first gear including an annular groove located on a side surface of the first gear and surrounding the first axis of rotation,

[0007] - a deflector including a ramp portion for guiding the lubricant, a part of the ramp portion being located within the annular groove of the first gear.

[0008] Thus, in cooperation with the ramp portion of the deflector, the annular groove of the gear is used to cause the lubricant to rise by centrifugal action. Specifically, the lubricant can be more effectively transferred from the bottom to the top of the first gear. The lubrication of the speed reducer is thus improved.

[0009] The speed reducer may further include at least one of the following features:

[0010] - the annular groove axially leads to one side of the first gear.

[0011] - the first gear includes a hub, a toothed peripheral belt radially arranged outside the hub (relative to the axis of rotation X), and a disk connecting the hub and the toothed peripheral belt.

[0012] - the annular groove of the first gear is defined on the side surface of the first gear by the hub, the disk, and the toothed peripheral belt.

[0013] - The ramp portion includes a main guide rail and an axial projection that extends the main guide rail and projects axially from the main guide rail, and the axial projection is partially or entirely disposed within the annular groove of the first gear.

[0014] - The main guide rail is entirely disposed outside the annular groove of the first gear.

[0015] - The reduction device includes a second gear that is rotatable about a second axis of rotation parallel to the first axis of rotation, and the second gear includes a toothed peripheral belt that is radially disposed with respect to the second axis and faces the main guide rail of the ramp portion.

[0016] - The diameter of the second gear is greater than the diameter of the first gear, for example, between 1.5 and 4 times larger, and when the reducer is in a position corresponding to the position adopted when installed on a horizontally parked vehicle, the first axis of rotation is disposed above the second axis.

[0017] - The horizontal plane that is tangent to the first wheel and located below the first axis is arranged higher than the horizontal plane that is tangent to the second wheel and located below the second axis.

[0018] - The first wheel is disposed above the oil level, particularly below the nominal oil level NN.

[0019] - The first gear and the second gear are axially offset relative to each other.

[0020] - In particular, if on the one hand a first plane passing through the first axis of rotation and the second axis of rotation is considered, and on the other hand a second plane corresponding to the horizontal plane passing through the second axis of rotation is considered, an angle between 10 degrees and 45 degrees separates the first plane and the second plane.

[0021] - The ramp portion, particularly the main guide rail of the ramp portion:

[0022] - Is arranged to cover a part of the second gear along a limited angular sector with respect to the second axis of rotation, and

[0023] - Is spaced apart from the tooth set of the second gear to allow lubricant to flow between the ramp portion and the second gear.

[0024] - The angular sector can be between 20 degrees and 90 degrees, for example, between 30 degrees and 50 degrees.

[0025] - The main guide rail is spaced apart from the second gear by a first clearance.

[0026] - The second gear is the drive wheel of the differential drive device.

[0027] - The shape of the main guide rail encloses the toothed peripheral belt of the second gear covered by the ramp portion.

[0028] - The first gap is between 2 mm and 5 mm.

[0029] - The tooth set of the second gear is inclined, for example helically inclined, and the inclination of the tooth set causes the lubricant to be axially guided to the same side as the first gear.

[0030] - The deflector includes a shield arranged on at least one side of the ramp portion to prevent the lubricant from falling from that side of the ramp portion.

[0031] - In a variant, the shield is formed on the housing.

[0032] - The shield extends in a plane substantially perpendicular to the second rotation axis.

[0033] - The shield is located on the same side of the ramp portion as the first gear.

[0034] - The shield is located on the same side of the main guide rail of the ramp portion as the first gear. Such a shield enables the lubrication of the speed reducer to be improved. Specifically, the shield can direct the lubricant towards the side of the first gear. Thus, by centrifugal action causing the lubricant to rise, the lubricant can be more effectively transferred from the bottom to the top of the first gear.

[0035] - The shield and the axial projection are located on the same side of the main guide rail of the ramp portion.

[0036] - The axial projection includes a guide rail extending in a plane parallel to the first rotation axis.

[0037] - When viewed in the plane of the axial projection, the annular groove has a cross-section with a shape complementary to the edge of the axial projection. In other words, the axial projection and the annular groove are axially nested within each other.

[0038] - The annular groove is bounded by a wall, and a second gap separates the axial projection from the wall of the annular groove. The second gap can be greater in the axial direction than in the radial direction.

[0039] - In a variant, the second gap is substantially constant along the wall of the annular groove.

[0040] - The speed reducer includes a housing surrounding the speed reduction means, and the deflector is manufactured as a component different from the housing, for example made of plastic, in particular by an injection molding method.

[0041] - The deflector includes a mounting portion that includes a plurality of fixing elements that cooperate with complementary fixing elements arranged in the housing of the speed reducer.

[0042] - The housing of the speed reducer includes a first part and a second part, which are assembled together with each other, enclose the speed reduction device, and fixing elements are arranged such that at least one fixing element is fixed to the first part of the housing and at least one fixing element is fixed to the second part of the housing.

[0043] - The mounting part includes a plate extending substantially in a plane perpendicular to the first axis of rotation, and fixing elements are arranged on each side of the plate.

[0044] - The fixing elements are mounting bolts, and the complementary fixing elements belonging to the housing are mounting seats.

[0045] - The fixing bolts project from the plate.

[0046] - The speed reducer includes a first shaft on which a first gear is mounted.

[0047] The speed reducer includes a first bearing which is arranged to guide the first shaft to rotate about the first axis X, the first bearing is mounted in the first seat of the housing, and an end region of the ramp portion of the deflector is arranged such that:

[0048] - It is axially arranged along the first axis of rotation between the first gear and the first bearing,

[0049] - Radially with respect to the first axis of rotation, closer to the first axis of rotation than the outer diameter of the first bearing,

[0050] - More radially close to the first axis of rotation than the outer diameter of the first gear.

[0051] - The speed reduction device includes a third gear which is made to rotate about the first axis of rotation and meshes with a second gear, the second gear and the third gear are arranged in the same plane, and the third gear is arranged outside the upper end of the ramp portion of the deflector.

[0052] - The outer diameter of the third gear is smaller than the outer diameter of the annular groove.

[0053] - The spacing distance between the third gear and the ramp portion is less than 3 cm, preferably less than 2 cm.

[0054] - The third gear is the output wheel of the first shaft.

[0055] - The first gear is the input wheel of the first shaft.

[0056] - The deflector is manufactured as a component different from the housing, for example, made of plastic, especially by an injection molding method.

[0057] - In a variant, the deflector is formed as a single piece with the first part of the housing.

[0058] - When observed in a plane perpendicular to the first axis of rotation, the shape of the ramp portion of the deflector has a circumferential (or tangential) component that increases as it gets closer to the first axis of rotation.

[0059] - The reduction gear includes an input shaft parallel to the first axis and a first double reduction stage, the first double reduction stage comprising:

[0060] - On the one hand, for the first transmission ratio, a first pinion coaxial with the input shaft and non-rotatable independently of the input shaft and a fourth gear meshing with the first pinion and capable of rotating the first shaft about the first axis of rotation; and

[0061] - On the other hand, for the second transmission ratio, a second pinion coaxial with the input shaft and non-rotatable independently of the input shaft and a first gear meshing with the second pinion and capable of rotating the first shaft about the first axis of rotation,

[0062] The reduction gear includes ratio selection means that can be fixed to the first shaft such that it cannot rotate independently thereof, or the first gear or the fourth gear.

[0063] Thus, the present invention is particularly advantageous in such a two-speed reduction architecture where it is difficult to properly disperse the lubricant. Since the first gear is necessarily driven to rotate when the motor is running (regardless of the selected transmission ratio), the lubricant can be properly dispersed regardless of the selected transmission ratio.

[0064] The present invention also relates to a power transmission system including a motor and a reduction gear as described above. Where appropriate, the motor includes a rotor shaft that can be coaxial with the input shaft of the reduction gear and cannot rotate independently of the input shaft.

[0065] Further features and advantages of the present invention are revealed by the following description of non-limiting exemplary embodiments of various aspects of the present invention. Description of the Drawings

[0066] With reference to the accompanying drawings, other features and advantages of the present invention will become apparent by reading the following description, wherein:

[0067] Figure 1 is a side view of a reduction gear according to a first embodiment, with the housing not shown.

[0068] Figure 2 is Figure 1 a perspective view of the reduction gear of

[0069] Figure 3 is a perspective view of a deflector of a first embodiment, with the housing and the differential wheel removed.

[0070] Figure 4Is a view schematically depicting the installation of the deflector in the housing in the first embodiment.

[0071] Figure 5 Is a view of a part of the housing cooperating with the deflector according to the first embodiment.

[0072] Figure 6 Is a view showing the cooperation between the protrusion of the deflector and the annular groove of the driven wheel according to the first embodiment.

[0073] Figure 7 Is a partial side view of the deflector according to the second embodiment.

[0074] Figure 8 Is a perspective view of the deflector according to the third embodiment.

[0075] Figure 9 Is a perspective view of the deflector and the bottom of the housing according to the fourth embodiment. Detailed Description

[0076] In the following description, the first axis of rotation is referred to as the axis of rotation X, the second axis of rotation is referred to as the axis of rotation Y, and the third axis of rotation is referred to as the axis of rotation Z.

[0077] In the specification and claims, the terms "external" and "internal" and the orientations "axial" and "radial" will be used to denote the elements of the transmission system according to the definitions given in the specification. By convention, the "axial" orientation refers to the reference axis X, Y or Z or a direction parallel to these axes, while the "radial" orientation refers to being orthogonal to the reference axes X, Y and Z. A "radially internal" element is closer to the reference axis than a "radially external" element.

[0078] The first axis mentioned above and in the claims corresponds to the intermediate shaft 120 in the embodiments described below.

[0079] The first gear mentioned above and in the claims corresponds to the driven wheel 122 of the second transmission ratio in the embodiments described below.

[0080] The second gear mentioned above and in the claims corresponds to the differential wheel 30 in the embodiments described below.

[0081] The third gear mentioned above and in the claims corresponds to the third pinion 123 in the embodiments described below.

[0082] The fourth gear mentioned above and in the claims corresponds to the driven wheel 121 of the first transmission ratio in the embodiments described below.

[0083] The terms "upper", "lower", "higher", "lower", "top" and "bottom" shall be considered when observing the speed reducer at a position / tilt similar to its position when the speed reducer is installed on a vehicle parked horizontally.

[0084] Figure 1 is a simplified side view of the speed reducer 1 (also known as the reducer), with its housing not shown so that the reduction device can be seen. Figure 2 The same reducer 1 is shown in perspective, without the housing and without Figure 1 the oil collector 40 shown.

[0085] In Figure 1 it is shown that the position of the reducer corresponds to its position when installed in a vehicle parked on a horizontal plane. It includes a relatively lower part and a relatively higher part.

[0086] Such a reducer includes two transmission ratios. It can form the main power transmission system of the vehicle, especially for electric vehicles, or the auxiliary power transmission system. For example, this can be the auxiliary electric power transmission system of a hybrid vehicle, especially for the rear axle of the vehicle.

[0087] The reducer 1 includes:

[0088] - An input shaft 110, which is intended to be driven by a motor, especially an electric motor, around the rotation axis Z,

[0089] - A differential drive device 130 (also known as a differential), which includes a differential wheel 30 and a differential shaft 300. The differential shaft 300 can rotate two half shafts around the rotation axis Y,

[0090] - An intermediate shaft 120, which can rotate around the rotation axis X and is capable of transmitting torque between the input shaft 110 and the differential wheel 30.

[0091] The input shaft 111 can be coaxially driven by the rotor shaft of the motor, especially through splines.

[0092] The differential wheel 30 drives the differential shaft 300 to rotate around the rotation axis Y in a known manner. The differential wheel 30 is the driving wheel of the differential drive device.

[0093] The rotation axes X, Y and Z are parallel.

[0094] The rotation axis Y is intended to be located on the vehicle, towards the front of the vehicle relative to the rotation axis X. Similarly, the rotation axis X is intended to be located on the vehicle, towards the front of the vehicle relative to the rotation axis Z.

[0095] In other words, the reduction gear has a front part AV and a rear part AR. The front part AV is intended to be positioned more towards the front of the vehicle than the rear part AR. Thus, the differential is positioned towards the front part of the reduction gear and the input shaft is positioned towards the rear part. Thus, when the vehicle has an engaged forward gear ratio, the differential wheel 30 rotates in the direction shown by the arrow T.

[0096] The diameter of the differential wheel 30 is greater than the diameter of the driven wheel 122 of the second gear ratio, for example between 1.5 and 4 times greater, and when the reduction gear is in a position corresponding to the position adopted when mounted on a horizontally parked vehicle, the axis of rotation X is arranged above the axis of rotation Y.

[0097] In particular, if on the one hand one considers 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, the angle between 10 and 45 degrees separates the first plane and the second plane.

[0098] The reduction gear 1 includes a first double reduction stage E1 between the input shaft 110 and the intermediate shaft 120. The reduction gear also includes a second reduction stage E2 between the intermediate shaft 120 and the differential shaft 300.

[0099] The first double reduction E1 includes:

[0100] - On the one hand, for the first gear ratio, a first pinion 111 that cannot rotate independently of the input shaft 110 relative to the axis of rotation Z and a driven wheel 121 that meshes with the first pinion 111 and is capable of rotating the intermediate shaft 120 about the axis of rotation X; and

[0101] - On the other hand, for the second gear ratio, a second pinion 112 that cannot rotate independently of the input shaft 110 relative to the axis of rotation Z and a driven wheel 122 that meshes with the second pinion 112 and is capable of rotating the intermediate shaft 120 about the axis of rotation X.

[0102] The terms "driven wheel 121 of the first gear ratio" and "driven wheel 122 of the second gear ratio" will be used in the remainder of the specification.

[0103] The second reduction stage E2 includes a third pinion 123 that cannot rotate independently of the intermediate shaft 120 relative to the axis of rotation X and a differential wheel 30 that can rotate about the axis of rotation Y, the differential wheel 30 meshing with the third pinion 123.

[0104] The driven wheel of the second gear ratio 122 and the differential wheel 30 are axially offset relative to each other.

[0105] Therefore, the change in the transmission ratio occurs in the first double reduction stage E1 via the ratio selection device 400. The ratio selection device 400 includes a fork 401 that can move translationally parallel to the axis of rotation X. The fork can be moved by a known actuating device (not shown). The fork 401 allows the claw coupling engagement sleeve to slide along the axis of rotation X in order to fix the intermediate shaft 120 to the driven wheel 121 of the first transmission ratio or the driven wheel 122 of the second transmission ratio. For this purpose, each of the driven wheels 121 of the first transmission ratio and 122 of the second transmission ratio includes a set of engagement teeth arranged around the axis of rotation X and capable of cooperating with the engagement sleeve. The driven wheels 121 of the first transmission ratio and 122 of the second transmission ratio are rotatably mounted around the intermediate shaft 120, and the engagement sleeve itself is mounted on the intermediate shaft 120 such that it cannot rotate independently thereof, for example by means of splines. Thus, it is the cooperation between the engagement sleeve and the set of engagement teeth of the driven wheel 121 of the first transmission ratio or the driven wheel 122 of the second transmission ratio respectively that enables the driven wheel 121 of the first transmission ratio or the driven wheel 122 of the second transmission ratio respectively to be fixed to the intermediate shaft 120 and not to be able to rotate independently around the axis of rotation X. The engagement sleeve includes engagement teeth, for example, at its two axial ends.

[0106] Preferably, the engagement sleeve can be kept spaced apart from the driven wheel 121 of the first transmission ratio and the driven wheel 122 of the second transmission ratio in the neutral position, in which no torque is transmitted between the input shaft 110 and the intermediate shaft 120 because neither the driven wheels 121 and 122 of the first and second transmission ratios interact with the engagement sleeve. The neutral position corresponds to the disengaged mode. In this mode, the motor no longer transmits torque to the two half shafts and also no longer transmits torque to the wheels in contact with the road, and vice versa.

[0107] The reduction gear, 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, and the claw clutch engagement sleeve all need to be lubricated, especially with oil. Here, the lubrication of the reduction gear is passive. In other words, it does not include a pump dedicated to circulating the lubricant within the reduction gear. Thus, the lubrication here relies on the presence of an oil bath at the bottom of the reduction gear and on the oil being conveyed in the direction of the various elements of the reduction gear to be lubricated (bearings, meshing gears, claw coupling tooth sets), especially by the splashing of the oil caused by the rotation of the differential wheel 30, the pinions 111, 112, 123 and the driven wheels 121, 122, and by gravity.

[0108] The term bearing here refers to both sliding bearings and rolling bearings.

[0109] When the vehicle is stationary, the lower part of the differential wheel 30 is immersed in an oil bath. When the vehicle is in motion, the differential wheel 30 rotates about the axis of rotation Y, which allows the oil to be dispersed, in particular to cause the oil to rise, as shown by the arrow F. As a result, the oil level at the bottom of the reducer decreases.

[0110] To improve the passive lubrication of the reducer, a deflector 20 is arranged at the lower part of the reducer to promote the rise of the lubricant, and a collector 40 is arranged at the upper part to receive on the one hand the lubricant that has risen beforehand and on the other hand to redirect the lubricant to various points of the reducer, in particular by gravity.

[0111] The deflector 20 is capable of guiding the splashing of the oil.

[0112] Figure 3 and Figure 4 A first embodiment of the deflector and the driven wheel 122 of the second gear ratio cooperating with the deflector is shown.

[0113] The gear 122 of the second transmission ratio includes an annular groove 11 which is arranged around the axis of rotation X and is axially open on one side of the gear 122 of the second transmission ratio. Here, the annular groove 11 is arranged on the right hand side of the driven wheel 122 of the second transmission ratio.

[0114] The driven wheel 122 of the second gear ratio includes a hub 1223, a toothed peripheral belt 1221 radially arranged outside the hub 1223, and a disc 1222 connecting the hub 1223 and the toothed peripheral belt 1221.

[0115] The annular groove 11 of the driven wheel 122 is bounded on the side of the driven wheel 122 by the hub 1223, the disc 1222 and the toothed peripheral belt 1221.

[0116] The deflector 20 includes a ramp portion 25 capable of guiding the lubricant. A part of the ramp portion 25 is arranged in the annular groove 11 of the driven wheel 122 of the second transmission ratio. The ramp portion is configured to introduce the lubricant into the annular groove of the driven wheel 122 of the second transmission ratio, so that the lubricant is centrifugally separated by the driven wheel 122 of the second transmission ratio and is thus redirected to the top of the reducer.

[0117] The lower edge of the ramp portion 25 is preferably arranged below the oil level, in particular below the nominal oil level NN. The nominal oil level corresponds to the indicated oil level on the reducer when the vehicle is stationary. Alternatively, the nominal oil level can correspond to the horizontal plane passing through the lower edge of the opening for filling / draining the reducer. The driven wheel 122 of the second transmission ratio is completely arranged above the nominal oil level by itself.

[0118] The ramp portion 25 includes a main guide rail 22 and an axial protrusion 21 extending the main guide rail 22 and protruding axially from the main guide rail 22.

[0119] The axial projection 21 is largely arranged within the annular groove 11 of the driven wheel 122 of the second transmission ratio. The main guide 22 itself is entirely arranged outside the annular groove 11 of the driven wheel 122 of the second transmission ratio.

[0120] The differential wheel 30 includes a toothed peripheral belt, a part of which is arranged radially facing the main guide 22 of the ramp portion 25 with respect to the axis of rotation Y.

[0121] The ramp portion 25 of the deflector, in particular the main guide 22 of the ramp portion 25, is arranged such that it covers the toothed peripheral belt of the differential wheel 30 along a limited angular sector with respect to the axis of rotation Y. The angular sector is between 20 degrees and 90 degrees, for example between 30 degrees and 50 degrees.

[0122] Furthermore, the ramp portion 25, in particular the main guide 22 of the ramp portion 25, is spaced from the tooth set of the differential wheel 30 by a first gap 31. This first gap can be between 2 mm and 5 mm

[0123] The main guide 22 advantageously has a shape that encloses the toothed peripheral belt of the differential wheel 30 covered by the ramp portion. In particular, in a plane perpendicular to the axis of rotation Y, the ramp portion 25 has the form of a circular arc.

[0124] The deflector 20 further includes a shield 23, which is arranged on at least one side of the ramp portion 25 to prevent lubricant from falling from that side of the ramp portion 25. The shield 23 is located on the same side of the ramp portion 25 as the driven wheel 122 of the second transmission ratio. The shield 23 and the axial projection 21 are located on the same side of the main guide 22 of the ramp portion 25.

[0125] The shield 23 extends in a plane substantially perpendicular to the axis of rotation Y. The shield takes the form of a plate arranged parallel to the differential wheel 30. The shield 23 is arranged to face axially a part of the differential wheel 30. Thus, the shield meets the ramp portion at least over half of its length.

[0126] The lower edge of the shield 23 can be arranged below the oil level, in particular below the nominal oil level.

[0127] In this example, the bottom of the shield 23 coincides with the bottom of the ramp portion 25.

[0128] The third pinion 123 is arranged outside the upper end of the ramp portion of the deflector. The outer diameter of the third pinion 123 is smaller than the outer diameter of the annular groove 11.

[0129] The speed reducer contains a lubricant such as oil, and when the speed reducer is in a position corresponding to the position adopted when installed on a horizontally parked vehicle, the lower end of the ramp portion is immersed in the lubricant.

[0130] The deflector 20 further includes a mounting portion 26.

[0131] The mounting part 26 includes a plate 27 extending substantially in a plane perpendicular to the axis of rotation X. The plate is preferably arranged in a continuation of the shroud 23, beyond the ramp part 25. In other words, the plate 27 and the shroud 23 are arranged in the same plane.

[0132] The mounting part 26 further includes a plurality of fixing bolts 29 which cooperate with seats 63 arranged in the reduction gear housing 60.

[0133] The fixing bolts 29 are arranged on each side of the plate 27. In Figure 3 the illustrated embodiment, the deflector includes four fixing bolts, namely two fixing bolts 29 arranged on one side of the plate 27 and two fixing bolts 29 arranged on the other side of the plate 27. The fixing bolts 29 project from the plate. They extend perpendicular to the plate 27.

[0134] The housing includes a first part 61 and a second part 62 which are assembled together with each other to enclose the reduction gear. The first part 61 may also form all or part of the motor housing.

[0135] The first part 61 includes two mounting seats 63 which cooperate with two fixing bolts 29 of the deflector, and the second part 62 includes two other mounting seats 63 which cooperate with two other fixing bolts 29 of the deflector.

[0136] In another embodiment not shown, the mounting seats are formed on the deflector and the fixing bolts are formed on the housing.

[0137] Figure 4 The mounting of the deflector 20 in the two parts 61 and 62 of the housing 60 is schematically described.

[0138] The intermediate shaft 120 extends along the axis of rotation X and carries a driven wheel 122 of the second transmission ratio.

[0139] The first bearing 66 guides the rotation of the intermediate shaft 120 about the axis of rotation X. The first bearing 66 is mounted in a first seat 69 made in the first part 61 of the housing 60. The first bearing 66 supports the first end of the intermediate shaft 120.

[0140] The second bearing 67 guides the rotation of the intermediate shaft 120 about the axis of rotation X. The second bearing 67 is mounted in a second seat made in the second part 62 of the housing 60.

[0141] Since it is manufactured as a component different from the housing 60, the end region 28 of the deflector 20, in particular including the axial projection 21, can be arranged radially with respect to the first axis of rotation X closer to the axis of rotation X than the outer periphery of the first bearing 66.

[0142] The end region 28 of the deflector is arranged axially along the first axis X between the driven wheel 122 of the second transmission ratio and the first bearing 66.

[0143] This feature is also visible in Figure 1 where only the outer ring of the bearing 66 with an outer diameter d66 is depicted. It can be seen that the deflector penetrates an axially straight cylindrical volume centered on the rotational axis X, the diameter of which corresponds to the outer diameter d66 of the first bearing 66.

[0144] The end region 28 of the deflector is arranged axially along the first axis X between the driven wheel of the second transmission ratio and the first bearing 66.

[0145] As previously mentioned, due to the cooperation between the axial projection and the annular groove of the driven wheel 122 of the second transmission ratio, the end region 28 of the deflector is also arranged radially with respect to the first axis X closer to the rotational axis X than the outer peripheral diameter of the driven wheel 122 of the second transmission ratio.

[0146] In Figure 5 it can be seen that the housing 60 also includes a complementary ramp portion 64 arranged in the continuation of the ramp portion 25 of the deflector 20, so that the lubricant is guided from the complementary ramp portion 64 of the housing 60 to the ramp portion 25 of the deflector 20.

[0147] It can be noted that the complementary ramp portion 64 has a channel 641 to allow the lubricant to return at the bottom of the complementary ramp portion, especially under the action of gravity. Thus, the lubricant can fall back to the bottom of the circular recess corresponding to the position of the differential wheel 30 in the housing. Preferably, the bottom of the circular recess is the lowest point of the internal volume of the housing.

[0148] The complementary ramp portion and the channel can be formed on two parts 61 and 62 of the housing 60. This is particularly advantageous when the differential wheel 30 is located in the axial assembly plane of the first part 61 and the second part 62 of the housing 60.

[0149] The deflector is made of plastic as a component different from the housing, for example, using an injection molding method. Thus, deflectors of various shapes can be envisaged.

[0150] In different configurations of the speed reducer, it is conceivable that the deflector is formed as a single piece with one of the first part or the second part of the housing.

[0151] Returning to Figure 3 the embodiment of, it can be seen that the axial projection 21 extends substantially in a plane parallel to the rotational axis X, or even in a plane containing the rotational axis X

[0152] When observed in the plane of the axial projection ( Figure 6), the annular groove 11 has a cross-section with a shape complementary to the edge of the axial projection (21). In other words, the axial projection 21 and the annular groove 11 are axially nested within each other. A second axial gap between 1 and 3 mm can, for example, separate the projection 21 and the groove 11. This gap can be larger in the axial direction than in the radial direction.

[0153] In Figure 6 the embodiment, when observed in a plane perpendicular to the axis of rotation X, the ramp portion 25 of the deflector has such a shape that its inclination has a circumferential or tangential (with respect to the axis of rotation X) component that increases as it gets closer to the axis of rotation X. Thus, the oil is gradually guided in a direction that makes it closer to the circumferential rotation of the driven wheel 122 of the second transmission ratio.

[0154] In Figure 8 the embodiment, as it gets closer to the driven wheel 122 of the second transmission ratio, the projection has an axially increasing thickness. This makes it possible to create a draft angle that is favorable for demolding the deflector.

[0155] In Figure 9 the variant, the housing does not have a complementary ramp portion, and the ramp portion includes a lower part that extends from the bottom of the shroud 23 towards the bottom of the housing 60.

[0156] A third gap j3 separates the bottom of the ramp portion 25 and the bottom of the housing 60 in order to allow the oil to return, especially under the action of gravity, below the lower end of the ramp portion 25 (in other words, below the bottom of the lower part of the ramp portion).

[0157] In the various embodiments described herein, the deflector makes it possible to lift the oil in the central region of the speed reducer, which is still blocked by the intermediate shaft 120, the driven wheels 121, 122, and the pinion 123.

[0158] Of course, the present invention has been described above by way of example. It should be understood that those skilled in the art can generate various alternative embodiments of the present invention without departing from the scope of the present invention. For example, the present invention described in the case of a speed reducer with two transmission ratios can also be applied to a speed reducer with a single transmission ratio or more than two transmission ratios.

[0159] It must be emphasized that all the features that those skilled in the art can see based on this specification, the drawings, and the appended claims, even if they are actually only described individually and in any combination relative to other given features, can be combined with other features or groups of features disclosed herein, as long as this is not explicitly excluded and the technical environment does not make such a combination impossible or meaningless.

Claims

1. A speed reducer (1) for a power train, comprising: - a reduction device, the reduction device including a first gear (122) capable of rotating about a first axis of rotation (X), the first gear (122) including an annular groove (11) located on a side surface of the first gear (122) and surrounding the first axis of rotation (X); - a deflector (20), the deflector (20) including a ramp portion (25) for guiding lubricant, a part of the ramp portion being located within the annular groove (11) of the first gear (122).

2. The speed reducer (1) according to claim 1, wherein, The ramp portion (25) includes a main guide rail (22) and an axial projection (21), the axial projection (21) extending the main guide rail (22) and axially protruding from the main guide rail (22), the axial projection (21) being partially or entirely arranged within the annular groove (11) of the first gear (122).

3. The speed reducer (1) according to claim 2, wherein, The reduction device includes a second gear (30) capable of rotating about a second axis of rotation (Y) parallel to the first axis of rotation (X), the second gear (30) including a toothed peripheral belt radially arranged with respect to the second axis (Y), the toothed peripheral belt facing the main guide rail of the ramp portion.

4. The speed reducer (1) according to claim 3, wherein, The diameter of the second gear (30) is greater than the diameter of the first gear (122), for example between 1.5 and 4 times larger, and when the speed reducer is in a position corresponding to that adopted when installed on a horizontally parked vehicle, the first axis of rotation X is arranged above the second axis (Y).

5. The speed reducer (1) according to claim 3 or 4, wherein, The first gear (122) and the second gear (30) are axially offset relative to each other.

6. The speed reducer (1) according to any one of claims 3 to 5, wherein, The second gear (30) is a drive wheel 30 of a differential drive device 130.

7. The speed reducer (1) according to any one of claims 3 to 6, wherein, The tooth set of the second gear (30) is inclined, for example helically inclined, and the inclination of the tooth set causes the lubricant to be axially guided to the same side as the first gear (122).

8. The speed reducer (1) according to any one of claims 3 to 7, wherein, The reduction device includes a third gear (123) made to rotate about the first axis of rotation (X) and meshing with the second gear (30), the second gear (30) and the third gear (123) being arranged in the same plane, the third gear (123) being arranged outside the upper end of the ramp portion (25) of the deflector (20).

9. The speed reducer (1) according to any one of claims 2 to 8, wherein, The deflector (20) includes a shield (23), the shield (23) being arranged on at least one side of the main guide rail (22) of the ramp portion (25) to prevent the lubricant from falling from that side of the ramp portion.

10. The speed reducer (1) according to claim 9, wherein, The shield (23) is located on the same side of the main guide rail (22) of the ramp portion (25) as the first gear (122).

11. The speed reducer (1) according to any one of claims 2 to 10, wherein, When observed in the plane of the axial projection, the annular groove (11) has a cross-section with a shape complementary to the edge of the axial projection (21).

12. The speed reducer (1) according to any one of the preceding claims, wherein, The speed reducer includes a housing (60) surrounding the reduction device, the deflector (20) being manufactured as a component different from the housing (60), for example made of plastic, in particular by an injection molding method.

13. The speed reducer (1) according to claim 12, wherein, The deflector (20) includes a mounting part (26), and the mounting part (26) includes a plurality of fixing elements (29), and the fixing elements (29) cooperate with complementary fixing elements (63) arranged in the housing (60) of the speed reducer.

14. The speed reducer (1) according to claim 13, wherein, The housing (60) of the speed reducer includes a first part (61) and a second part (62), and these two parts are assembled with each other to surround the speed reduction device. The fixing elements (29) are arranged such that at least one fixing element (29) is fixed to the first part (61) of the housing, and at least one fixing element (29) is fixed to the second part (62) of the housing.

15. The speed reducer (1) according to claim 13 or 14, wherein, The fixing element (29) is a mounting bolt, and the complementary fixing element (63) belonging to the housing (60) is a mounting seat.

16. The speed reducer (1) according to any one of claims 12 to 15, wherein, The speed reducer includes a first shaft (120) on which the first gear (122) is mounted, and a first bearing (66) arranged to guide the first shaft (120) to rotate about the first rotation axis (X). The first bearing (66) is mounted in the first seat (69) of the housing (60), and wherein, the end region of the ramp part (25) of the deflector (20) is arranged to: - Axially be arranged between the first gear (122) and the first bearing (66) along the first rotation axis (X), - Radially with respect to the first rotation axis (X), be closer to the rotation axis X than the outer peripheral diameter of the first bearing (66), - Be more radially close to the rotation axis X than the outer peripheral diameter of the first gear (122).

17. The speed reducer (1) according to any one of claims 12 to 15, wherein, The speed reduction device includes a first shaft (120) on which the first gear (122) is mounted, an input shaft (110) parallel to the first shaft (120), and a first double reduction stage (E1). The first double reduction stage (E1) includes: - On the one hand, for a first transmission ratio, a first pinion (111) coaxial with the input shaft (110) and not capable of rotating independently of the input shaft (110), and a fourth gear (121) meshing with the first pinion (111) and capable of causing the first shaft (120) to rotate about the first rotation axis (X); and - On the other hand, for a second transmission ratio, a second pinion (112) coaxial with the input shaft (110) and not capable of rotating independently of the input shaft (110), and a first gear (122) meshing with the second pinion (112) and capable of causing the first shaft (120) to rotate about the first rotation axis (X), The speed reduction device includes ratio selection means, and the ratio selection means can be fixed to the first shaft (120) such that the first gear (122) or the fourth gear (121) cannot rotate independently of the first shaft (120).

18. The speed reducer (1) according to any one of the preceding claims, wherein, The first gear (122) includes a hub (1223), a toothed outer peripheral band (1221) radially arranged outside the hub (1223), and a web (1222) connecting the hub (1223) and the toothed outer peripheral band (1221), and the annular groove (11) is defined on one side of the first gear (122) by the hub (1223), the web (1222) and the toothed outer peripheral band (1221).

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