Gear lubrication device

Abstract

The present invention relates to a lubrication device (20) for a gear (30, 31, 34, 35, F32, A32, X2) of a reducer (1), the gear (30) having helical teeth formed of at least one tooth (32) and at least one groove (33), the lubrication device (20, 21, D1) being disposed laterally with respect to the gear (30) and fixed so as to rotate with the gear (30). Fig. 2.

Description

Title of the invention: Lubrication device for gear wheel

[0001] The present invention relates to the technical field of lubrication devices, and more particularly to a lubrication device for gear wheel of speed reducer.

[0002] It is already known that a pump can be used to lubricate a speed reduction device, particularly bearings and gears, by circulating a lubricant such as oil in a lubrication circuit configured to reach different specific areas requiring lubrication. These gearbox lubrication devices are called "active." For example, such a device is described in document FR2982003, in which a pump supplies oil to a gearbox via a trough acting as a reservoir within the gearbox casing. The trough supplies oil to the rotating shafts of the gearbox via a plurality of orifices. This device has the disadvantage of being energy-intensive to operate the pump and bulky.

[0003] There are also so-called "passive" lubrication devices, i.e., those without a pump, in which channels are formed to facilitate the upward flow of lubricant from the bottom of the gearbox, thus dispersing the lubricant in different areas of the gearbox. However, these passive lubrication solutions are not entirely satisfactory, and the upward flow of lubricant from the bottom of the gearbox is sometimes insufficient, particularly because the gears of the transmission shaft obstruct the upward flow of lubricant.

[0004] Moreover, all the dimensions of the gear are chosen to optimize torque transmission and not to optimize pumping.

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

[0006] For this purpose, the present invention proposes a lubrication device for a gear reducer, the gear comprising helical teeth formed of at least one tooth and at least one groove, the lubrication device being disposed laterally with respect to the gear and fixed so as to rotate with the gear.

[0007] This allows for more efficient recovery and dispersion of the lubricating fluid.

[0008] According to one embodiment of the invention, the lubrication device is formed by at least one plate fixed to the gear wheel or to a shaft on which the gear wheel is mounted.

[0009] Such a plate thus makes it possible to retain and block laterally the lubricating fluid which circulates during the rotation of the gear.

[0010] According to one embodiment of the invention, the lubrication device extends from a shaft on which the gear wheel is mounted to the end of the teeth of the gear wheel.

[0011] According to one embodiment of the invention, at least a part of the lubrication device is pressed against the toothed wheel, the radial end of the lubrication device not being in contact with the toothed wheel.

[0012] This avoids interfering with another gear or gear system

[0013] According to one embodiment of the invention, the radial end of the lubrication device is serrated or corrugated.

[0014] According to one embodiment of the invention, the bumps formed by the undulation of the end of the lubrication device are in contact with the solid parts of the teeth of the gear and form pockets for the recovery of a lubricating fluid.

[0015] According to one embodiment of the invention, the device includes openings to allow air to be admitted between the lubrication device and the toothed wheel.

[0016] According to one embodiment of the invention, the lubrication device is formed by at least one pre-stressed plate on the toothed wheel.

[0017] The invention also relates to a speed reducer comprising a lubrication device according to the invention.

[0018] The invention also relates to a motor propulsion unit for a motor vehicle comprising a speed reducer according to the invention.

[0019] 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:

[0020] - Fig. 1 is a schematic cross-sectional representation of a speed reducer according to one embodiment of the invention,

[0021] - [Fig. 2] is a schematic representation of a toothed wheel comprising a lubrication device according to an embodiment of the invention,

[0022] - [Fig.3] is a schematic cross-sectional representation of a gear comprising a lubrication device according to an embodiment of the invention,

[0023] - [Fig. 4] is a schematic representation of part of a gear comprising a lubrication device according to another embodiment of the invention,

[0024] - [Fig. 5] is a schematic representation of the lubrication device according to a another embodiment of the invention,

[0025] - [Fig. 6] is a schematic cross-sectional representation of part of a wheel toothed part comprising a lubrication device according to another embodiment of the invention,

[0026] - [Fig.7] is a schematic cross-sectional representation of a gear comprising a lubrication device according to another embodiment of the invention, a) before mounting the lubrication device on the gear, b) after mounting the lubrication device on the gear,

[0027] - [Fig.8] is a schematic cross-sectional representation of part of a wheel toothed comprising a lubrication device according to another embodiment of the invention.

[0028] Figure 1 illustrates a speed reducer 1 comprising a lubrication device 20 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 secondary powertrain. For example, it may be a secondary electric powertrain of a hybrid vehicle, in particular intended for the rear axle of the vehicle.

[0029] In [Fig.1] the speed reducer 1 is shown without its closing cover so as to visualize the inside of the speed reducer 1.

[0030] According to one embodiment of the invention, the speed reducer comprises a reduction device 10 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 a differential input wheel 30,

[0031] - an intermediate shaft 110 movable in rotation about a third axis of rotation X3, and capable of transmitting torque between input shaft 100 and differential input wheel 30.

[0032] According to one embodiment of the invention, the reduction device 10 is housed in a closed enclosure 70 formed by a casing 60 and a closing cover (not illustrated) disposed on the casing.

[0033] According to one embodiment of the invention, a portion of the housing 60 is filled with a lubricating fluid to lubricate the reduction device 10. 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 of the reducer to the top of the reducer and to be dispersed throughout the different areas of the reducer.

[0034] According to one embodiment of the invention, the lubricating fluid is oil.

[0035] 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.

[0036] The top and bottom of the reducer are defined with respect to its position when mounted in a vehicle.

[0037] According to an embodiment of the invention illustrated [Fig.2], the toothed wheel 30 has an opening 31 in its center for the passage of the second shaft 120.

[0038] The differential gear 30 of the speed reducer 1 has helical teeth formed of teeth 32 and grooves 33 between each tooth. Thus, as it rotates, the teeth 32 of the gear 30 carry the lubricating fluid to disperse it within the reducer 1. The angle A32 between the axis X32 of the tooth 32 and the axis of rotation X2 is approximately 15°. This angle allows a tangential flow F32, opposite to the direction of rotation of the gear 30, into the grooves 33 between the teeth 33.

[0039] In the context of the invention, in order to avoid dispersion losses due to the lateral flow created by the angle A32 of inclination of the teeth 32, the gear 30 includes a lubrication device 20. The lubrication device 20 is fixed so as to rotate with the gear 30. This allows for more efficient recovery and dispersion of the lubricating fluid.

[0040] According to one embodiment of the invention, the lubrication device 20 is formed by at least one plate 20.

[0041] According to one embodiment of the invention, the plate 20 is disposed on the side 34 of the gear 30 towards which the tangential flow F32 of the lubricating fluid is directed. Such a plate thus makes it possible to retain and laterally block the lubricating fluid which flows along the path F32 during the rotation of the gear 30.

[0042] More specifically, plate 20 is located on the side where the lubricating fluid is sprayed when the vehicle is operating in forward gear.

[0043] According to one embodiment of the invention, the diameter DI of the plate is less than or equal to the diameter of the gear wheel 30. More specifically, the diameter DI of the plate 20 is determined so as not to interfere with another gear wheel or another gear system.

[0044] According to one embodiment of the invention, the plate 20 is fixed to the second shaft 120, which allows it to rotate at the same time as the gear.

[0045] According to one embodiment of the invention, the plate 20 is fixed by welding, press fitting, free centering on the shaft and axial pinching between two toothed wheels, free centering and drive by obstacle of notch type, or any other type of compatible fixing.

[0046] According to one embodiment of the invention, the plate is fixed directly to the gear, allowing it to rotate simultaneously with the gear. In this case, the fixing is achieved by screwing or welding onto the gear or the gear support.

[0047] Thus, the plate 20 extends from the second shaft 120 to the end of the teeth 32 of the gear 30.

[0048] According to one embodiment of the invention, at least a part of the plate is pressed against the gear wheel 30. More specifically, the plate 20 is in contact 35 with solid parts of the teeth 32 forming the teeth of the gear wheel 30.

[0049] In this way, the plate 20 makes it possible to reduce the loss of lubricating fluid flow by preventing it from escaping from the grooves 33 of the gear 30.

[0050] According to an embodiment of the invention illustrated [Fig. 3], the radial end 22 of the plate 20 is not in contact with the gear 30 so as to avoid interfering with another gear or gear system. To this end, the plate has a step 23. That is to say, the radial end 22 forms a step 23, oriented opposite to the gear 30, which is therefore not in contact with the teeth 32 of the gear 30.

[0051] According to an embodiment of the invention illustrated in [Fig. 4] and [Fig. 5], the radial end 22 of the plate 20 is serrated or corrugated. The radial end 22 of the plate 20 thus has bumps 24, also called teeth, and hollows 25.

[0052] According to one embodiment of the invention, the bumps 24 of the plate are in contact 34 with the solid parts of the teeth 32 of the gear 30.

[0053] According to one embodiment of the invention, the bumps 24 form ribs at the periphery and their height gradually decreases towards the center of the plate 20 so as to form a pocket 26. Each pocket 26 is positioned opposite a groove 33 of the gear 30. This allows the lubricating fluid to be collected and then re-dispersed under centrifugal force.

[0054] According to one embodiment of the invention, the number of bumps 24 of the plate 20 is equal to the number of teeth 32 of the gear 30.

[0055] According to an embodiment of the invention illustrated [Fig.5], the bumps have their longitudinal axis X24 parallel to the axis X32 of the teeth 32 of the gear 30. That is to say, the pockets 26 are in line with the grooves 33. This allows better recovery of the lubricating fluid.

[0056] According to an embodiment of the invention illustrated [Fig.6], the plate 20 has openings 27 to allow an air intake Al between the plate 20 and the toothed wheel 30, which will facilitate the flow A2 of the lubricating fluid and its evacuation A3.

[0057] According to an alternative embodiment of the invention illustrated [Fig.7], the plate 20 is pre-stressed 36 onto the gear wheel.

[0058] To this end, according to one embodiment of the invention, the plate 20 has a conical shape. More precisely, the plate 20 has a conical shape [Fig. 7] a) before its mounting on the gear 30 and then a flat shape [Fig. 7] b) after mounting on the gear 30.

[0059] According to one embodiment of the invention, the cone-shaped plate 20 is arranged on the wheel so that its radial end 22 bears against the gear 30 and its center 21 is offset from the gear 30. Thus, during the mounting and fastening 36 of the plate 20 onto the gear 30 by its center 21, the fastening pressure flattens the cone. This creates a pre-stress on the plate, which generates a constant force exerted on the gear. During the rotation of the gear, relative displacements between the plate and the gear occur, allowing some of the vibrational energy to be absorbed. Such a cone-shaped plate thus limits the vibrations of the gearbox while also limiting the loss of lubricating fluid.

[0060] According to an embodiment of the invention illustrated [Fig.8], the lubrication device is formed by at least two plates 20, 20'. This makes it possible to increase the wetting surface and therefore the volume of lubricating fluid carried.

[0061] The two plates 20, 20' are identical or each include one or more of the characteristics of the variants described above.

[0062] 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. Lubrication device (20) for gear wheel (30) of reducer (1), the gear wheel (30) having helical teeth formed of at least one tooth (32) and at least one groove (33), characterized in that the lubrication device (20) is disposed laterally with respect to the gear wheel (30) and fixed so as to rotate with the gear wheel (30).

2. Lubrication device (20) according to claim 1, wherein the lubrication device is formed by at least one plate fixed to the gear (30) or to a shaft (120) on which the gear (30) is mounted.

3. Lubrication device (20) according to claim 1 or 2, wherein the lubrication device (20) extends from a shaft (120) on which the gear wheel (30) is mounted to the end of the teeth (32) of the gear wheel (30).

4. Lubrication device (20) according to any one of claims 1 to 3, wherein at least a portion of the lubrication device (20) is pressed against the gear wheel (30), the radial end (22) of the lubrication device (20) not being in contact with the gear wheel (30).

5. Lubrication device (20) according to any one of claims 1 to 4, wherein the radial end (22) of the lubrication device (20) is serrated or corrugated.

6. Lubrication device (20) according to claim 5, wherein the bumps (24) formed by the undulation of the end of the lubrication device (20) are in contact (34) with the solid parts of the teeth (32) of the gear wheel 30 and form pockets (26) for recovering a lubricating fluid.

7. Lubrication device (20) according to any one of claims 1 to 6, comprising openings (27) to allow air (Al) to be admitted between the lubrication device (20) and the toothed wheel (30).

8. Lubrication device (20) according to any one of claims 1 to 7, wherein the lubrication device is formed by at least one plate (20) pre-stressed on the gear (30).

9. Speed ​​reducer (1) comprising a lubrication device (20) according to any one of claims 1 to 8.

10. Motor vehicle propulsion unit comprising a speed reducer (1) according to claim 9.

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