Speed reducer with integrated lubrication

Abstract

The present invention relates to a speed reducer (1) comprising a reduction device arranged in a casing (60) comprising 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 bearing an input wheel of the differential (30), - an intermediate shaft (110) able to transmit torque between the input shaft (100) and an input wheel of the differential (30), the speed reducer (1) being configured to allow the lubricating fluid to be raised vertically, in two steps, from the second shaft (120) to the intermediate shaft (110), then from the intermediate shaft (110) to the input shaft (100).

Description

[0001] Description

[0002] Title of the invention: Speed ​​reducer with integrated lubrication

[0003] The present invention relates to the technical field of speed reducers, and more particularly to a speed reducer with an integrated lubrication device.

[0004] 11. It is already known that for lubricating a speed reducer device, particularly bearings and gears, a pump circulates a lubricant such as oil through a lubrication circuit configured to reach different specific areas requiring lubrication. These reducer lubrication devices are called "active." One such 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.

[0005] 11. There are also so-called "passive" lubrication systems, meaning 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 on 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.

[0006] Furthermore, all the dimensions of the gear are chosen to optimize torque transmission, not pumping. Lubricating the vertical gearboxes is therefore difficult due to the distance between the oil level and the input shaft, which is located at the top.

[0007] 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.

[0008] The present invention therefore aims to overcome one of the drawbacks of prior art inventions by proposing a speed reducer with an improved passive lubrication system. 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:

[0009] an input shaft intended to be driven by a motor, in particular an electric machine,

[0010] 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,

[0011] 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.

[0012] Such a system allows for better lubrication of the speed reducer.

[0013] According to one embodiment of the invention, the speed reducer includes a first wall to channel 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.

[0014] According to one embodiment of the invention, the first wall is formed by a rim configured to allow the lubricating fluid to rise towards the intermediate shaft.

[0015] According to one embodiment of the invention, the rim is disposed between the two shafts. According to another embodiment of the invention, the speed reducer includes a second wall for channeling the lubricating fluid to the intermediate shaft located at the intermediate shaft wheel.

[0016] According to one embodiment of the invention, the second wall is formed by a rim configured to allow the lubricating fluid to rise towards the input shaft, the second wall being arranged on a face opposite to that where the first wall is located.

[0017] 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.

[0018] According to one embodiment of the invention, the lubrication device comprises at least two reservoirs for the lubricating fluid.

[0019] Such a system allows for better lubrication of the speed reducer. According to one embodiment of the invention, a first reservoir is arranged to collect the dispersed lubricating fluid.

[0020] According to one embodiment of the invention, a second reservoir is arranged to recover the lubricating fluid poured from the first reservoir.

[0021] According to one embodiment of the invention, the second tank is arranged below the first tank, relative to the top and bottom of the reducer.

[0022] According to one embodiment of the invention, the second tank is held in place by the bottom of the casing and a cover, for example by gluing or welding or pinching.

[0023] According to one embodiment of the invention, the first reservoir and the second reservoir are connected by a channel allowing the lubricating fluid to flow from the first reservoir to the second reservoir.

[0024] The invention also relates to a speed reducer comprising a lubrication device according to the invention.

[0025] The invention also relates to a motor-drive unit for a motor vehicle comprising a speed reducer according to the invention.

[0026] 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, which are given by way of example and in which:

[0027] - Figure 1 is a schematic cross-sectional representation of a speed reducer according to an embodiment of the invention in a first stage of operation.

[0028] - Figure 2 is a schematic cross-sectional representation of a speed reducer according to an embodiment of the invention in a second operating stage.

[0029] - [Fig. 3] is a schematic representation of the operation of the speed reducer illustrating the circulation of the fluid according to an embodiment of the invention.

[0030] - Figure 4 is a schematic cross-sectional representation of a speed reducer according to an embodiment of the invention showing the filling of the first reservoir,

[0031] - [Fig. 5] is a schematic cross-sectional representation of a speed reducer according to an embodiment of the invention showing the filling of the second reservoir, - [Fig. 6] is a schematic representation of the lubrication device according to an embodiment of the invention.

[0032] Figures 1 to 5 illustrate a speed reducer 1, comprising a passive lubrication device 21, 22 according to the invention. This speed reducer 1 is generally integrated into a main powertrain of a vehicle, particularly an electric motor vehicle, or into a secondary powertrain. For example, it could be a secondary electric powertrain of a hybrid vehicle, specifically intended for the rear axle of the vehicle.

[0033] According to one embodiment of the invention, the speed reducer comprises a reduction device including at least:

[0034] - an input shaft 100 intended to be driven by a motor, in particular an electric machine, around a first axis of rotation XI,

[0035] - a second shaft 120 extending along a second axis of rotation X2 and coaxially carrying an input wheel of the differential 30,

[0036] - an intermediate shaft 110 movable in rotation around a third axis of rotation X3, and capable of transmitting a torque between the input shaft 100 and the input wheel of the differential 30.

[0037] 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 the opposite direction to that of the intermediate shaft 110.

[0038] 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 disposed on the casing.

[0039] 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.

[0040] According to one embodiment of the invention, the lubricating fluid is oil. According to one embodiment of the invention, the speed reducer 1 is installed in a vehicle so that a part of the toothed wheel 30 is immersed in the lubricating fluid.

[0041] The top H and bottom B of the reducer are defined with respect to its position when mounted in a vehicle.

[0042] 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 SI. 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.

[0043] In the context of the invention, to channel the lubricating fluid to the intermediate shaft 110, a first flange 21 is arranged 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 arranged to extend between the two shafts 110 and 120, from the second shaft 120 to the intermediate shaft 110.

[0044] According to one embodiment of the invention, the first wall 21 is oriented upwards in the gearbox H to promote a vertical flow of the lubricating fluid. 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, thereby drawing the lubricating fluid F2 in a direction of rotation SI. The lubricating fluid is drawn and dispersed F2, in part, towards the input shaft 100.

[0045] In the context of the invention, to channel the lubricating fluid to the intermediate shaft 120, a second wall 22 is arranged at the level of the intermediate shaft 120's impeller. The second wall 22 is formed from the cover on a face opposite to that where the first wall 21 is located. More specifically, the gearbox 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 and 100. According to another embodiment of the invention, the first wall 21 is oriented towards the top of the gearbox H so as to promote a vertical flow of the lubricating fluid. The lubricating fluid is carried and dispersed, in part, towards the input shaft 100 and the surface 63 at the top of the housing 60.

[0046] The fluid can then fall back down, to lubricate the assembly and start a cycle Fl, F2 again. Thus, the lubricating fluid circulates Fl from the second shaft 120 to the intermediate shaft 110 and then to the input shaft 100.

[0047] 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. More precisely, the two walls 21 and 22 are orthogonal to the axes XI, X2, X3 and extend parallel to the axes XI, X2, X3.

[0048] According to one embodiment of the invention, the two walls 21, 22 thus delimit a second partial housing 64 inside the housing 70 which also promotes the vertical rise of the lubricating fluid towards the top H of the reducer while avoiding its lateral dispersion on the walls of the housing 70.

[0049] In the context of the invention, in order to optimize the recycling of the lubricating fluid to the bottom B of the reducer, the lubrication device 20 [Fig. 6] comprises at least two receptacles or reservoirs 23, 24 for the lubricating fluid [Fig. 4]. In the context of the invention, the housing 60 is not considered as one of the two reservoirs or receptacles.

[0050] Such a system allows for better lubrication of the speed reducer 1.

[0051] According to one embodiment of the invention, a first reservoir 23 is arranged to collect the lubricating fluid dispersed by the wheel of the intermediate shaft 120 at the top H of the reducer 1. More specifically, the first reservoir 23 is arranged at the top of the reducer on one side of the input shaft 100 from which the lubricating fluid is ejected, that is to say on the side towards which the direction of rotation SI of the input shaft 100 is oriented.

[0052] According to one embodiment of the invention, the first reservoir 23 is held in place by the bottom of the housing and the cover, for example by positioning pins on the reservoir, which fit into corresponding bores in the housing 60. The fastening is therefore only complete when the cover is fixed to the housing 60 [the reservoir is "sandwiched"] or by screwing. The reservoir 23 is intended to lubricate elements such as gears, bearings, the dynamic seal of the shaft 100 and all or part of the elements of the shaft 110 by means of pipettes not shown.

[0053] According to one embodiment of the invention [Fig. 5], a second reservoir 24 is arranged to recover the lubricating fluid poured from the first reservoir 23.

[0054] According to one embodiment of the invention, the second reservoir 24 is arranged below the first reservoir 23, with respect to the top H and the bottom B of the reducer defined previously.

[0055] According to one embodiment of the invention, the second reservoir 24 is held in place by the bottom of the housing and the cover, for example by positioning pins on the reservoir, which fit into corresponding bores in the housing 60. The fixing is therefore only complete when the cover is fixed on the housing 60 [the reservoir is "sandwiched") or by screwing.

[0056] According to one embodiment of the invention, the first reservoir 23 and the second reservoir 24 are connected by a channel 25. This channel 25 allows the lubricating fluid to flow from the first reservoir 23 to the second reservoir 24.

[0057] According to one embodiment of the invention, the reservoirs 23, 24 and the channel are formed in a single piece directly from the casing 60, made of plastic or aluminum.

[0058] According to one embodiment of the invention, the tanks 23, 24 and the channel are formed by three additional pieces made of plastic or aluminum or of plastic for the first tank 23 and of aluminum for the second tank 24.

[0059] According to one embodiment of the invention, one of the reservoirs 23, 24 is an additional part, and the other is formed in a single piece directly from the casting of the casing 60.

[0060] According to one embodiment of the invention, the two reservoirs 23, 24 are formed in a single piece directly from the casting of the casing 60.

[0061] The invention also relates to a speed reducer comprising a lubrication device according to the invention.

[0062] The invention also relates to a motor-drive unit for a motor vehicle comprising a speed reducer according to the invention.

[0063] Such a system allows for better lubrication of the speed reducer. The invention also relates to a speed reducer comprising a lubrication device according to the invention.

[0064] The invention also relates to a motor-drive unit for a motor vehicle comprising a speed reducer according to the invention.

[0065] 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 illustrative only and may be modified without 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 supporting 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 rise of the lubricating fluid from the second shaft (120) to the intermediate shaft (110), 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 level of the intermediate shaft (110) disposed at the level of 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 configured to allow the lubricating fluid to rise (Fl) towards the intermediate shaft (110).

4. Speed ​​reducer (1) according to claim 3, in which the rim is disposed between the two shafts (110, 120).

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, in which the second wall (22) is formed by a rim 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 any one of claims 1 to 6, comprising at least two reservoirs (23, 24) for the lubricating fluid.

8. Speed ​​reducer (1) according to claim 7, in which a first reservoir (23) is arranged to recover the dispersed lubricating fluid.

9. Lubrication device (20) according to any one of claims 7 or 8, wherein a second reservoir (24) is arranged to recover the lubricating fluid discharged from the first reservoir (23) 10. Powertrain for motor vehicle comprising a speed reducer (1) according to any one of claims 1 to 9.

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