Speed ​​reducer with integrated lubrication

Abstract

The present invention relates to a speed reducer (1) comprising a reduction device disposed in a housing (60) containing a lubricating fluid, the reduction device comprising at least: an input shaft (100) intended to be driven by a motor, in particular an electric machine, a second shaft (120) coaxially carrying an input wheel of the differential (30), an intermediate shaft (110) adapted to transmit torque between the input shaft (100) and an input wheel of the differential (30), the speed reducer (1) being configured to allow, in two stages, the vertical upward flow of the lubricating fluid from the second shaft (120) to the intermediate shaft (110), and then from the intermediate shaft (110) to the input shaft (100). Fig. 1.

Description

Title of the invention: Speed ​​reducer with integrated lubrication

[0001] The present invention relates to the technical field of speed reducers, and more particularly to a speed reducer with an integrated lubrication device.

[0002] It is already known that to lubricate a speed reducer device, particularly bearings and gears, a pump can be used to circulate a lubricant such as oil in a lubrication circuit configured to reach different specific areas requiring lubrication. These reducer lubrication devices are called "active." Such a device is described, for example, in document FR2982003, in which a pump supplies oil to the rotating shafts of the gearbox. This device has the disadvantage of being energy-intensive to operate the pump and bulky.

[0003] There are also so-called "passive" lubrication systems, i.e., those without a pump, in which the rotation of the various gears disperses the lubricant to different areas of the gearbox. However, these passive lubrication solutions are not entirely satisfactory. Indeed, the upward flow of lubricant from the bottom to the top of the gearbox is insufficient to properly lubricate it, particularly because the gears of the transmission shaft obstruct the upward flow of lubricant. This is further complicated when the differential gear or ring gear of the gearbox rotates in the opposite direction to that of the secondary gear.

[0004] Moreover, in all cases, the dimensions of the gear are chosen to optimize torque transmission and not to optimize pumping. Lubrication of the vertical reducers is therefore difficult to achieve due to the distance between the oil level and the input shaft, which is located at the top.

[0005] The present invention therefore aims to overcome one of the drawbacks of those of the prior art by proposing a speed reducer with an improved passive lubrication device.

[0006] To this end, the present invention proposes a speed reducer comprising a reduction device disposed in a housing containing a lubricating fluid, the reduction device comprising at least: - an input shaft intended to be driven by a motor, in particular an electric machine, - a second shaft coaxially supporting an input wheel of the differential, - an intermediate shaft capable of transmitting torque between the input shaft and an input wheel of the differential,

[0007] the speed reducer being configured to allow, in two stages, the vertical rise of the lubricating fluid from the second shaft to the intermediate shaft, then from the intermediate shaft to the input shaft.

[0008] Such a system allows for better lubrication of the speed reducer.

[0009] According to one embodiment of the invention, the speed reducer includes a first wall for channeling the lubrication fluid at the level of the intermediate shaft located at the level of the differential wheel, on the side of the intermediate shaft.

[0010] According to one embodiment of the invention, the first wall is formed by a rim of the housing configured to allow the lubricating fluid to rise towards the intermediate shaft.

[0011] According to one embodiment of the invention, the rim is arranged between the two trees.

[0012] According to one embodiment of the invention, the speed reducer includes a second wall to channel the lubrication fluid at the level of the intermediate shaft located at the level of the intermediate shaft wheel.

[0013] According to one embodiment of the invention, the wall is formed by a rim of the housing configured to allow the lubricating fluid to rise towards the input shaft, the second wall being disposed on a face opposite to that where the first wall is located.

[0014] According to one embodiment of the invention, the two walls are arranged along an axis parallel to the axes of the shafts of the speed reducer.

[0015] The invention also relates to a motor vehicle powertrain comprising a speed reducer according to the invention.

[0016] Other objects, features and advantages of the invention will be better understood and will become more apparent upon reading the description given below, with reference to the accompanying figures, given by way of example and in which:

[0017] - Fig. 1 is a schematic cross-sectional representation of a reducer speed according to an embodiment of the invention in a first stage of operation,

[0018] - [Fig.2] is a schematic cross-sectional representation of a reducer of speed according to an embodiment of the invention in a second operating stage,

[0019] - [Fig. 3] is a schematic representation of the operation of the reducer speed illustrating the circulation of the fluid according to an embodiment of the invention.

[0020] Figures 1 and 2 illustrate a speed reducer 1, without the cover, comprising a passive lubrication device 21, 22 according to the invention. This speed reducer 1 is generally integrated within a main powertrain of a vehicle, in particular an electric motor vehicle, or a group secondary powertrain. For example, this could be a secondary electric powertrain of a hybrid vehicle, specifically intended for the rear axle of the vehicle.

[0021] According to one embodiment of the invention, the speed reducer comprises a reduction device including at least: - an input shaft 100 intended to be driven by a motor, in particular an electric machine, around a first axis of rotation XI, - a second shaft 120 extending along a second axis of rotation X2 and coaxially carrying an input wheel of the differential 30,

[0022] - an intermediate shaft 110 movable in rotation about a third axis of rotation X3, and capable of transmitting torque between the input shaft 100 and the input wheel of the differential 30.

[0023] According to one embodiment of the invention, the input shaft 100 rotates in a direction of rotation SI, driving the intermediate shaft 110 in a direction of rotation S2, which in turn drives the second shaft 120 in a direction of rotation SI. The rotation of the differential wheel 30 by the second shaft 120 is in a direction opposite to that of the intermediate shaft 110.

[0024] According to one embodiment of the invention, the reduction device is housed in a closed enclosure 70 formed by a casing 60 and a closing cover (not illustrated) disposed on the casing.

[0025] According to one embodiment of the invention, a portion of the housing 60 is filled with a lubricating fluid to lubricate the reduction device. More specifically, the housing 60 is filled with lubricating fluid such that the gear 30 is partially immersed in the fluid. In this way, when the gear 30 rotates, it carries the lubricating fluid with it. This allows the lubricating fluid to rise from the bottom B of the reducer to the top H of the reducer and to be dispersed throughout the different areas of the reducer 1.

[0026] According to one embodiment of the invention, the lubricating fluid is oil.

[0027] According to one embodiment of the invention, the speed reducer 1 is installed in a vehicle in such a way that part of the toothed wheel 30 is immersed in the lubricating fluid.

[0028] The top H and the bottom B of the reducer are defined with respect to its position when mounted in a vehicle.

[0029] In the context of the invention, according to a first operating step [Fig. 1], the differential wheel 30, during its operation, rotates in a direction SL. Since the rotation of the differential wheel 30 is in the opposite direction to that of the intermediate shaft 110, the lubricating fluid is carried Fl in a direction of rotation S2. The lubricating fluid is carried and dispersed Fl, in part, towards the intermediate shaft 110.

[0030] In the context of the invention, to channel the lubricating fluid to the intermediate shaft 110, a first flange 21 is disposed at the differential wheel 30, on the side 61 of the intermediate shaft 110 [Fig. 1]. The flange 21 is formed from the housing 60. More specifically, the housing 60 has a lip configured to allow the lubricating fluid to flow upwards Fl towards the intermediate shaft 110 [Fig. 3]. According to one embodiment of the invention, the lip 21 is disposed so as to extend between the two shafts 110, 120, from the second shaft 120 to the intermediate shaft 110.

[0031] According to one embodiment of the invention, the first wall 21 is oriented towards the top of the reducer H so as to promote a vertical rise of the lubricating fluid.

[0032] In the context of the invention, according to a second operating step [Fig.2], the wheel of the intermediate shaft 120, during its operation, rotates in a direction S2, the lubricating fluid is thus carried F2 in a direction of rotation SL. The lubricating fluid is carried and dispersed F2, in part, towards the input shaft 100.

[0033] In the context of the invention, to channel the lubricating fluid at the intermediate shaft 120, a second wall 22 is arranged at the level of the wheel of the intermediate shaft 120. The wall 22 is formed from the housing 60 on a face opposite to that where the first wall 21 is located. More specifically, the housing 60 has a rim configured to allow the lubricating fluid to flow upwards F2 towards the input shaft 100 [Fig. 3]. According to one embodiment of the invention, the rim 22 is arranged between the two shafts 110, 100.

[0034] According to one embodiment of the invention, the first wall 22 is oriented towards the top of the reducer H so as to promote a vertical rise of the lubricating fluid.

[0035] The lubricating fluid is carried and dispersed, in part, towards the input shaft 100 and the surface 63 of the top of the housing 60.

[0036] The fluid can thus fall back down, to lubricate the assembly and start a cycle Fl, F2 again.

[0037] Thus, the lubricating fluid circulates Fl from the second shaft 120 to the intermediate shaft 110 to the input shaft 100.

[0038] According to one embodiment of the invention, the two walls 21, 22 are arranged along an axis parallel to the axes XI, X2, X3 of the shafts of the speed reducer 1.

[0039] According to one embodiment of the invention, the two walls 21, 22 thus delimit a second partial casing 64 inside the casing 70 which also facilitates the ascent vertical flow of the lubricating fluid upwards H of the reducer, avoiding its lateral dispersion on the walls of the casing 70.

[0040] Such a system allows for better lubrication of the speed reducer.

[0041] The invention also relates to a speed reducer comprising a lubrication device according to the invention.

[0042] The invention also relates to a motor propulsion unit for a motor vehicle comprising a speed reducer according to the invention.

[0043] The scope of the present invention is not limited to the details given above and allows for embodiments in many other specific forms without departing from the field of application of the invention. Therefore, the present embodiments should be considered by way of illustration and may be modified without, however, departing from the scope defined by the claims.

Claims

Demands

1. Speed ​​reducer (1) comprising a reduction device disposed in a housing (60) containing a lubricating fluid, the reduction device comprising at least: - an input shaft (100) intended to be driven by a motor, in particular an electric machine, - a second shaft (120) coaxially carrying an input wheel of the differential (30), - an intermediate shaft (110) capable of transmitting torque between the input shaft (100) and an input wheel of the differential (30), characterized in that the speed reducer (1) is configured to allow, in two stages, the vertical upward movement of the lubricating fluid from the second shaft (120) to the intermediate shaft (110), and then from the intermediate shaft (110) to the input shaft (100).

2. Speed ​​reducer (1) according to claim 1, comprising a first wall (21) for channeling the lubrication fluid at the intermediate shaft (110) disposed at the differential wheel (30), on the side of the intermediate shaft (110).

3. Speed ​​reducer (1) according to claim 2, wherein the first wall (21) is formed by a rim of the casing (60) configured to allow the lubricating fluid to rise (Fl) towards the intermediate shaft (110).

4. Speed ​​reducer (1) according to claim 2 or 3, wherein the rim (21) is disposed between the two shafts (110, 220).

5. Speed ​​reducer (1) according to any one of claims 1 to 4, comprising a second wall (22) for channeling the lubrication fluid at the intermediate shaft (120) disposed at the wheel of the intermediate shaft (120)

6. Speed ​​reducer (1) according to claim 5 when it depends on claims 2 to 4, wherein the wall (22) is formed by a rim of the casing (60) configured to allow the lubricating fluid to rise F2 towards the input shaft (100), the second wall (22) being disposed on a face (62) opposite to that (61) where the first wall (21) is located.

7. Speed ​​reducer (1) according to claim 5, when it depends on claims 2 to 4, or 6, wherein the two walls (21, 22) are arranged along an axis parallel to the axes (XI, X2, X3) of the shafts of the speed reducer (1).

8. Powertrain for motor vehicle comprising a speed reducer (1) according to any one of claims 1 to 7.