INTERNALLY LUBRICATED TRANSMISSION MECHANISM AND ASSOCIATED ELECTRIC PROPULSION ASSEMBLY

Abstract

A transmission mechanism (M) comprising: - a casing (40a); - at least one transmission shaft (10) rotatable relative to the casing about an axis of rotation (X1) and comprising a pinion with teeth; - a guide bearing (100a) supporting the transmission shaft relative to the casing which comprises rolling elements (103), the guide bearing being inserted into a cylindrical housing (41) arranged in the casing, in which a protective plate (70) axially covers the rolling elements (103) of the guide bearing without contact, the guide bearing is interposed axially between the bottom of the cylindrical housing and the protective plate which comprises a lubricating fluid discharge passage (72) located in the lower part of said plate relative to the axis of rotation when the transmission mechanism (M) is in a reference operational position. (Abstract figure: 3)

Description

Title of the invention: INTERNALLY LUBRICATED TRANSMISSION MECHANISM AND ASSOCIATED ELECTRIC PROPULSION ASSEMBLY TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to the internal lubrication, for example by splashing, of the components of a transmission mechanism, and in particular of a speed reduction mechanism. STATE OF THE PRIOR ART

[0002] To lubricate the components of a transmission mechanism, and in particular the rotating guide bearings and gears of such a mechanism, it is known to arrange the moving components of the mechanism inside a casing containing oil, but without the moving components, for example a transmission shaft supporting pinions, being completely immersed in the oil. It is then the movement of the transmission mechanism which, by splashing, stirs the oil and projects it throughout the entire interior volume of the casing, to ensure the desired lubrication of the entire mechanism, including the non-immersed parts.

[0003] Guide bearings, for example of the ball bearing type, must be permanently lubricated and are generally crossed by a flow of lubricating oil. When they are insufficiently lubricated, the guide bearings risk heating up. Conversely, when they are over-lubricated, the guide bearings lose efficiency, particularly at high speeds, and the general efficiency of the speed reduction mechanism decreases. A compromise must be found between the imperative of sufficient lubrication and the desire to minimize the energy consumption induced by the mixing of the oil, which tends to introduce too much oil into the rolling elements of the guide bearing.

[0004] To control the flow of lubricating fluid within the guide bearing, an oil deflector comprising a protrusion that channels the flow of oil to the rear of the guide bearing can be placed in the bottom of the cylindrical housing that accommodates the guide bearing, as illustrated for example in document EP2112405A1. The protrusion directs the flow of oil inside the transmission shaft to be evacuated at the level of the pinion teeth supported by the shaft. This oil deflector does not, however, protect the guide bearing from oil splashes on the front face that result from the mixing of the oil. The flow of oil passing through the guide bearing is not controlled and the energy losses remain significant.

[0005] Another disadvantage of this oil deflector is that it is necessary to maintain it in position within the casing by producing complex shapes which increase the production cost of such a casing. Statement of the invention

[0006] The invention aims to remedy the drawbacks of the state of the art and to propose a transmission mechanism combining good lubrication of the guide bearings and low energy consumption at high speed.

[0007] To do this, according to a first aspect of the invention, a splash lubrication transmission mechanism is proposed, comprising:

[0008] - a casing;

[0009] - at least one transmission shaft movable in rotation relative to the casing around of an axis of rotation of the transmission shaft and comprising a pinion with teeth;

[0010] - a guide bearing supporting the transmission shaft relative to the casing which comprises rolling elements, the guide bearing being inserted into a cylindrical housing provided in the casing,

[0011] in which a protective plate axially covers without contact the rolling elements of the guide bearing, the guide bearing is interposed axially between the bottom of the cylindrical housing and the protective plate which comprises a lubricating fluid discharge passage located in the lower part of said plate relative to the axis of rotation when the transmission mechanism is in a reference operational position.

[0012] The protective plate arranged on the front of the guide bearing, i.e. facing the pinion of the transmission shaft, makes it possible to prevent projections of lubricating fluid, for example oil, from entering the guide bearing. The lubricating oil no longer penetrates in an anarchic manner, the flow passing through the guide bearing is thus controlled.

[0013] For the purposes of the invention, the term “cover” means both covering with contact and covering without contact.

[0014] Preferably, the guide bearing may comprise a rotating inner ring, an outer ring that does not rotate relative to the housing, and rolling elements arranged between the two rings, the protective plate covering the space available between the non-rotating outer ring and the rotating inner ring of the guide bearing. For example, the guide bearing may be a ball bearing, a roller bearing, or a needle bearing.

[0015] Advantageously, the lubricating fluid discharge passage can open opposite the space available between the non-rotating outer ring and the rotating inner ring of the guide bearing.

[0016] According to a variant of the invention, the protective plate is fixed to the non-rotating outer ring of the guide bearing. In this case, the protective plate covers the guide bearing with contact. Fixing the protective plate to a fixed element of the transmission mechanism makes it possible to limit projections within the casing and to limit friction losses. For example, the protective plate may comprise fixing lugs snapped into an inner groove formed in the non-rotating outer ring.

[0017] Preferably, the protective plate may partially cover the casing, at least in an insertion zone of the guide bearing formed on the casing. In this way, the protective surface is increased and the inflow of the lubricating fluid into the guide bearing is better controlled.

[0018] According to a variant of the invention, the protective plate is axially supported on the casing, at least in the insertion zone of the guide bearing. In this case, the protective plate covers the casing with contact. The protective plate can then be fixed to the casing. For example, the protective plate can comprise fixing lugs snapped into an internal groove formed in the cylindrical housing.

[0019] According to another variant of the invention, the protective plate covers the insertion zone of the guide bearing without contact. In this case, an axial space of a few millimeters exists between the protective plate and the casing.

[0020] Advantageously, the protective plate may comprise a central bore into which the transmission shaft is inserted.

[0021] Preferably, the casing may comprise a groove opening into the upper part of the cylindrical housing, the protective plate at least partially covering the groove. In this way, the inflow of the lubricating fluid into the guide bearing is better controlled.

[0022] According to an exemplary embodiment, the casing comprises a groove opening into the upper part of the cylindrical housing, the protective plate at least partially covering the groove, and said lubricating fluid discharge passage being arranged substantially opposite the groove relative to the axis of rotation. In this way, the flow of lubricating oil is channeled within the guide bearing.

[0023] According to a variant of the invention, the lubricating fluid discharge passage is a slot passing right through the thickness of the protective plate. In this variant, the slot may be of elongated shape, for example oblong. This controls the outgoing flow of the lubricating fluid within the guide bearing. In this variant, the slot may open onto the outer periphery of the protective plate. Also, the slot may open opposite the space available between the non-rotating outer ring and the rotating inner ring of the guide bearing. This facilitates the evacuation of the lubricating fluid from the guide bearing.

[0024] According to another variant of the invention, the lubricating fluid discharge passage is a rib stamped into the protective plate which opens onto one of the edges of the protective plate.

[0025] According to yet another variant of the invention, the lubricating fluid discharge passage is a groove dug in the protective plate which opens onto one of the edges of the protective plate.

[0026] Preferably, the guide bearing insertion area may comprise a first substantially annular rim which surrounds the cylindrical housing and the guide bearing, the protective plate contactingly covering the first rim.

[0027] Advantageously, the insertion zone of the guide bearing may also comprise a second substantially annular rim arranged radially beyond the first rim and a groove arranged between the first and second rims, the protective plate covering the insertion zone up to the second rim. In this way, it is possible to improve the cooling of the guide bearing without increasing the quantity of fluid inside it. The protective plate covers the second rim with contact.

[0028] Preferably, the first rim and the second rim may be concentric.

[0029] Advantageously, the groove of the insertion zone may comprise a lubricating fluid inlet and a lubricating fluid outlet oriented vertically relative to the axis of rotation of the transmission shaft, the fluid inlet and the fluid outlet being notches formed in the second rim. This facilitates the flow of the lubricating fluid around the guide bearing.

[0030] Preferably, the groove of the insertion zone may comprise heat exchange fins with the casing distributed angularly around the axis of rotation.

[0031] Advantageously, the protective plate can directly form the second rim and the first oil inlet and / or the second oil inlet.

[0032] According to one aspect of the invention, the transmission mechanism may further comprise, housed in the casing, a first transmission shaft guided in rotation about a first axis of rotation by a first guide bearing and integral in rotation with at least one drive pinion, a second transmission shaft guided in rotation about a second axis of rotation by a second guide bearing and integral in rotation with at least one intermediate pinion, and a third transmission shaft guided in rotation about a third axis of rotation by a third guide bearing and integral in rotation with at least one driven pinion, the protective plate axially covers without contact the rolling elements of at least two guide bearings chosen from the first, the second and the third guide bearing.

[0033] Preferably, the first transmission shaft, the second transmission shaft and the third drive shaft can be parallel to each other.

[0034] Advantageously, the protective plate can be crossed by at least two transmission shafts chosen from among the first, the second and the third transmission shaft.

[0035] Preferably, the housing may comprise a molded or machined groove connecting two cylindrical guide bearing insertion housings, the protective plate covering the groove and thus forming a lubricating fluid passage conduit between the two cylindrical housings.

[0036] Advantageously, the transmission mechanism may comprise one or more gears establishing a fixed speed ratio between the driving pinion and the receiving pinion, this speed ratio being greater than one.

[0037] Preferably, the transmission mechanism may further comprise a differential housed in the casing, the third transmission shaft constituting an input member of the differential.

[0038] The invention is more particularly applicable to a reduction transmission mechanism, and in particular to a speed reducer with a fixed ratio or with two reduction ratios, to a reducer with parallel shafts or even to a speed reducer of the coaxial type comprising an epicyclic train, in which the axis of rotation of the electric motor is concentric with the output shaft of the epicyclic train.

[0039] According to another aspect of the invention, it relates to an electric propulsion assembly comprising an electric motor and a transmission mechanism incorporating all or part of the characteristics mentioned above, the transmission shaft constituting an output shaft of the electric motor or being integral in rotation with a drive shaft of the electric motor.

[0040] Preferably, the stator of the electric motor can be fixed to the housing. BRIEF DESCRIPTION OF THE FIGURES

[0041] Other characteristics and advantages of the invention will emerge on reading the description which follows, with reference to the appended figures.

[0042] [Fig.l] [Fig.l] partially illustrates an electric propulsion assembly including a transmission mechanism according to a first embodiment of the invention.

[0043] [Fig.2] [Fig.2] illustrates a partial front view of the transmission mechanism of [Fig.l], in a reference operational position.

[0044] [Fig.3] [Fig.3] illustrates a sectional view along a vertical plane of the transmission mechanism of [Fig.2], the latter being in the reference operational position.

[0045] [Fig.4] [Fig.4] illustrates a detailed view of the transmission mechanism according to a second embodiment of the invention.

[0046] [Fig.5] [Fig.5] illustrates a front view of the transmission mechanism according to a third embodiment of the invention, the latter being in a reference operational position.

[0047] [Fig.6] [Fig.6] illustrates a partial view of the transmission mechanism of [Fig.5].

[0048] [Fig.7] [Fig.7] illustrates a partial view of the transmission mechanism according to a fourth embodiment of the invention.

[0049] For clarity, identical or similar elements are identified by identical reference signs throughout the figures. DETAILED description of embodiments

[0050] In Figures 1 to 3 an electric propulsion assembly 1 is illustrated, comprising an electric machine 60 and a transmission mechanism M according to a first embodiment of the invention.

[0051] The electrical machine 60 may be, for example, an induction electric motor, comprising a rotor 62 and a stator 61, electrically powered with three-phase alternating current by accumulator batteries via a current converter (not shown in [Fig.l]).

[0052] The electrical machine 60 is held on a casing 40a, 40b. The casing is generally composed of a main casing 40a supporting the electrical machine 60 and a closing casing 40b bearing on the main casing 40a, at a joint plane 48, to seal a cavity delimited by the main casing 40a and the closing casing 40b.

[0053] The electric machine 60 rotates a first transmission shaft 10 which penetrates into the casing 40a. The first transmission shaft 10 constitutes an input shaft of the transmission mechanism M, which also comprises a second transmission shaft 20, and a third transmission shaft 30 which constitutes an output shaft of the transmission mechanism M.

[0054] The second transmission shaft 20 which constitutes an intermediate shaft of the transmission mechanism M is parallel to the input shaft 10 and the output shaft 30 of the transmission mechanism M.

[0055] As illustrated in [Fig.3], the input shaft 10 is aligned with the motor shaft 63 of the electrical machine 60 relative to the casing 40a, and carries at least one toothed wheel, here called motor pinion 11, linked in rotation to the transmission shaft. The input shaft 10 is guided by two guide bearings 100a, 100b in rotation so as to rotate around a first axis of rotation XI relative to the casing 40a.

[0056] The guide bearing 100a which supports the first transmission shaft relative to the casing comprises in particular rolling elements 103, in this case rolling balls. The guide bearing 100a is inserted into a cylindrical housing 41 provided in the casing 40a.

[0057] To lubricate the various components of the transmission mechanism M, the casing 40a, 40b contains lubricating oil. The guide bearings and the pinions of the transmission shafts are partially immersed in the oil. It is then the movement of the transmission mechanism which, by splashing, stirs the oil and projects it throughout the entire interior volume of the casing, to ensure the desired lubrication of the entire mechanism, including the non-immersed parts.

[0058] In the first embodiment of the invention, a protective plate 70 partially covers the casing, in an insertion zone 50 of the guide bearing formed on the casing. The insertion zone 50 of the guide bearing comprises a first substantially annular rim 51 which surrounds the cylindrical housing 41 and the guide bearing 100a. The protective plate 70 bears axially on the casing 40a, at least in the insertion zone 50 of the guide bearing. In this case, the protective plate 70 covers the casing 40a with contact.

[0059] The protective plate 70 is arranged axially between the drive pinion 11 and the guide bearing 100a. The protective plate 70 arranged on the front of the guide bearing, i.e. facing the drive pinion of the transmission shaft, makes it possible to prevent projections of lubricating fluid, for example oil, from being introduced into the guide bearing.

[0060] The output shaft 30 carries in joint rotation at least one driven pinion 31. The output shaft 30 further comprises a fixed connection in rotation with a planet carrier of a differential 32, or constitutes the planet carrier of the differential 32. The differential 32 can be open or with limited slip, depending on the desired properties. The output shaft 30 is guided by two guide bearings 300a, 300b in rotation so as to rotate around a third axis of rotation X3 relative to the casing 40a.

[0061] Like the input shaft 10 and the output shaft 30, the intermediate shaft 20 is guided by several guide bearings 200a, 200b in rotation about a second axis of rotation X2, and carries two intermediate pinions 21, 22 in joint rotation, the first intermediate pinion 21 forming a first speed reduction gear with the driving pinion 11 of the input shaft 10, and the second intermediate pinion 22 forming a second speed reduction gear with the receiving pinion 31 of the output shaft 30.

[0062] The first, second and third axes of rotation XI, X2, X3 are parallel to each other. The first axis of rotation XI and the third axis of rotation X3 are located in a reference plane P of the transmission mechanism M. The second axis of rotation X2 is located outside the reference plane P.

[0063] The motor pinion 11 has a diameter and a number of teeth smaller than the diameter and to the number of teeth of the intermediate pinion 21 of the intermediate shaft 20 forming the first speed reduction gear. Similarly, the second intermediate pinion 22 of the intermediate shaft 20 forming the second speed reduction gear has a diameter and a number of teeth smaller than the diameter and the number of teeth of the receiving pinion 31 of the output shaft 30. The transmission mechanism M is therefore reducing and without changing ratio.

[0064] For the remainder of the description, a reference operational position of the transmission mechanism M is defined as being the three-dimensional orientation in which the transmission mechanism M is installed in a vehicle horizontally. In this reference operational position, the second axis of rotation X2 is located above the reference plane P. In the remainder of this description, unless otherwise stated, the invention will be described in a reference operational position.

[0065] In [Fig.2] the transmission mechanism M is illustrated in a partial and simplified front view showing the first transmission shaft 10 guided in rotation by means of a guide bearing 100a, and in the reference operational position.

[0066] In use, the casing 40a is filled with lubricating oil up to a prescribed limit which corresponds to an oil level plane at rest, this oil level plane at rest being horizontal when the transmission mechanism is in the reference operational position.

[0067] A portion of the reference plane P of the transmission mechanism M, delimited by the input shaft 10 and the output shaft 30, is located above the oil level plane at rest.

[0068] An oil collecting tank 80 is arranged between the first transmission shaft 10 and the third transmission shaft 30. The oil collecting tank 80 retains a portion of the oil sprayed by the elements of the transmission mechanism which splash in the oil. The oil collecting tank 80 has at least one upper opening 82, located above the oil level plane at rest as well as outlet orifices 81 located below the upper opening 82. It is thus possible to precisely bring a flow of lubricating oil into an upper zone of the casing 40a.

[0069] The oil collecting tank 80 makes it possible to provide a dynamic oil level as a function of the rotational speed of the input shaft 10, and more precisely, to reduce the oil level when the speed increases, by retaining a portion of the oil sprayed by the elements of the transmission mechanism which splash in the oil.

[0070] At rest, that is to say when stopped, the oil collecting tank 80 located above the oil level plane at rest is empty, and the oil level corresponds to the plane of oil level at rest. The maximum oil level varies only slightly when the transmission mechanism M is operating at very low speed. This is explained by low-speed rotation of the driven pinion 31, the driven pinion 31 being the largest toothed wheel of the transmission mechanism M and therefore the wheel most capable of projecting the oil through the casing 40a.

[0071] The higher the rotation of the transmission shafts, the more oil will be thrown through the housing 40a by the rotation of the gears. When the oil is thrown into the housing 40a, it falls back • on a mechanical part such as a pinion or a bearing; and / or • in the bottom of the crankcase 40a where the oil rests; and / or • in the oil collecting tank 80 shown in [Fig.3].

[0072] The oil collected by the oil collecting tank 80 is then partly directed into a groove 45 formed in the casing 40a in order to be conveyed into the guide bearing 100a as illustrated by arrows in [Fig. 3]. The groove 45 opens into the upper part of the cylindrical housing 41.

[0073] To control the flow of lubricating fluid passing through the guide bearing 100a, the transmission mechanism M comprises a protective plate 70 axially covering without contact the rolling elements 103 of the guide bearing 100a. The guide bearing 100a is interposed axially between the bottom 41a of the cylindrical housing 41 and the protective plate 70. The protective plate 70 at least partially covers the groove 45 and comprises a lubricating fluid discharge passage 72 located in the lower part of said plate relative to the first axis of rotation XI when the transmission mechanism is in the reference operational position.

[0074] A flow of lubricating oil is therefore conveyed towards the guide bearing 100a to a space available between the bottom 41a of the cylindrical housing 41 and the rear face of the guide bearing 100a. By gravity, the lubricating fluid descends along the groove 45, then enters the cavity formed by the cylindrical housing of the casing 40a before exiting through a lower notch 55 formed in the casing and through the lubricating fluid discharge passage 72 provided on the protective plate 70. The lubricating fluid discharge passage 72 is a slot located in the lower part of said protective plate relative to the axis of rotation when the transmission mechanism M is in the reference operational position.

[0075] The guide bearing 100a comprises a rotating inner ring 101, an outer ring 102 which does not rotate relative to the housing and the rolling elements 103 arranged between the two rings. The protective plate 70 covers the space available between the non-rotating outer ring 102 and the inner ring 101 rotating guide bearing.

[0076] In this example, the lubricating fluid discharge passage 72 is a slot passing right through the thickness of the protective plate. The slot 72 is elongated, more particularly oblong. The slot 72 opens opposite the space available between the outer ring 102 and the inner ring 101 of the guide bearing. The lubricating fluid discharge slot 72 is oriented downwards relative to the first axis of rotation XI when the transmission mechanism M is in the reference operational position. The geometry and size of the slot 72 makes it possible to adjust the lubricating fluid discharge flow rate within the guide bearing.

[0077] To facilitate its integration within the transmission mechanism, the protection plate 70 comprises a central bore 73 in which the first transmission shaft 10 is inserted. The protection plate 70 is fixed on the non-rotating outer ring 102 of the guide bearing. In this case, the protection plate covers the guide bearing with contact. The protection plate 70 also comprises fixing lugs 74 snapped into an inner groove 104 formed in the non-rotating outer ring.

[0078] A second embodiment of the invention will now be described with reference to [Fig. 4], which differs from the previous one by a particular arrangement of the lubricating fluid discharge passage 72 relative to the first axis of rotation XI. In this embodiment, the lubricating fluid discharge passage 72 is a slot passing right through the thickness of the protective plate 70. The slot 72 is oblong in shape and opens opposite the space available between the outer ring 102 and the inner ring 101 of the guide bearing. However, the oblong shape is asymmetrical relative to a vertical plane passing through the first axis of rotation XI. The slot 72 is therefore angularly offset to favor the oil level in one direction of rotation. At low rotation speed, a certain quantity of oil is maintained within the guide bearing because the oil does not rise sufficiently to reach the bottom of the slot 72.At high rotational speed, the oil is rotated by the rolling elements 103 and reaches the bottom of the slot 72, thus allowing it to be evacuated. The quantity of oil inside the guide bearing is thus reduced.

[0079] A third embodiment of the invention will now be described with reference to FIGS. 5 and 6, which differs from the first embodiment in that the protective plate 70 axially covers the rolling elements 103 of the first, second and third guide bearings 100a, 200a, 300a.

[0080] Since the first transmission shaft 10, the second transmission shaft 20 and the third transmission shaft 30 are parallel to each other, the protective plate is crossed by the first, second and third transmission shafts 10, 20, 30.

[0081] As illustrated in [Fig.6], the housing 40a includes a molded groove 45 connecting two cylindrical guide bearing insertion housings 41. The protective plate 70 covers the groove 45 and thus forms a lubricating fluid passage conduit 46 between the two cylindrical housings.

[0082] At the level of the third transmission shaft 30, the protective plate 70 has a slot 72a which opens onto the outer periphery of the plate.

[0083] We will now describe with reference to [Fig.7], a fourth embodiment of the invention, which differs from the first embodiment by a different geometry of the insertion zone 50 of the guide bearing.

[0084] In this fourth embodiment, the insertion zone 50 of the guide bearing 100a comprises a first substantially annular rim 51 which surrounds the cylindrical housing 41 and the guide bearing, a second substantially annular rim 52 arranged radially beyond the first rim and a groove 53 arranged between the first and second rims 51, 52.

[0085] The protective plate 70 covers the insertion zone 50 up to the second edge 52. For greater efficiency, the protective plate 70 covers the first edge 51 and the second edge 52 in contact. The first edge and the second edge are concentric.

[0086] The groove 53 of the insertion zone comprises a lubricating fluid inlet 46 and a lubricating fluid outlet 47 oriented vertically relative to the axis of rotation XI of the first transmission shaft 10. The fluid inlet 46 and the fluid outlet 47 are notches 55 formed in the second rim 52. This facilitates the flow of the lubricating fluid around the guide bearing.

[0087] Finally, the groove 53 of the insertion zone 50 comprises fins 58 for heat exchange with the casing 40a distributed angularly around the first axis of rotation XI.

[0088] In this fourth embodiment, the lubricating oil captured by the oil collecting tank 80 is directed towards the lubricating fluid inlet 46 formed in the casing 40a in order to be conveyed partly into the guide bearing 100a and partly into the groove 53 of the insertion zone 50 as illustrated by arrows in [Fig.7].

[0089] Via the pipe 48, a flow of lubricating oil is conveyed towards the guide bearing 100a to a space available between the bottom 41a of the cylindrical housing 41 and the rear face of the guide bearing 100a. By gravity, the lubricating fluid enters the cavity formed by the cylindrical housing of the casing 40a before exiting through a lower notch 55a formed in the casing and by the lubricating fluid discharge passage 72 provided on the protective plate 70. The lubricating fluid discharge passage 72 is for example a groove dug in the protective plate which opens onto one of the edges of the protective plate of said protective plate relative to the axis of rotation when the transmission mechanism M is in the reference operational position.

[0090] The flow of lubricating oil passing through the groove 53 is divided into two parts and makes it possible to cool the first rim 51 and consequently the guide bearing 100a without it being necessary to introduce more lubricating oil inside the latter.

[0091] Naturally, the examples shown in the figures and discussed above are given for illustrative purposes only and are not limiting. It is explicitly provided that the different embodiments illustrated can be combined with each other to propose others.

[0092] According to a variant not illustrated, the transmission mechanism M is of the coaxial type comprising an epicyclic train.

[0093] The transmission mechanism described above is a reduction mechanism with a constant speed ratio to an intermediate shaft, but the invention is also intended to be applied to mechanisms with several intermediate shafts, or without an intermediate shaft, to mechanisms with several speed ratios, and / or to mechanisms whose ratio of the input speed to the output speed is less than 1.

[0094] The transmission mechanism M described above is a speed reducer mechanism with internal splash lubrication, but the invention is also intended to be applied to a speed reducer mechanism with internal lubrication under pressure in which the oil is directed via pipes or hoses to the main points of the reducer to be lubricated. The oil then falls by gravity into the bottom of the casing. In this other example, a mechanical or electric pump can be used to bring the fluid under pressure into the pipes or hoses.

Claims

Claims

1. Transmission mechanism (M) with internal lubrication, comprising: - a casing (40a, 40b); - at least one transmission shaft (10, 20, 30) movable in rotation relative to the casing around an axis of rotation (XI, X2, X3) of the transmission shaft and comprising a pinion with teeth;- a guide bearing (100a, 200a, 300a) supporting the transmission shaft relative to the casing which comprises rolling elements (103, 203, 303), the guide bearing being inserted into a cylindrical housing (41) arranged in the casing, characterized in that a protective plate (70) axially covers without contact the rolling elements of the guide bearing, the guide bearing is interposed axially between the bottom (41a) of the cylindrical housing (41) and the protective plate which comprises a lubricating fluid discharge passage (72, 72a) located in the lower part of said plate relative to the axis of rotation when the transmission mechanism (M) is in a reference operational position.;

2. Transmission mechanism (M) according to claim 1, characterized in that the guide bearing (100a, 200a, 300a) comprises a rotating inner ring (101, 201, 301), an outer ring (102, 202, 302) not rotating relative to the casing (40a, 40b) and the rolling elements (103, 203, 303) arranged between the two rings, the protective plate covering the space available between the non-rotating outer ring and the rotating inner ring of the guide bearing.

3. Transmission mechanism (M) according to the preceding claim, characterized in that the lubricating fluid discharge passage (72, 72a) opens opposite the space available between the non-rotating outer ring (102, 202, 302) and the rotating inner ring (101, 201, 301) of the guide bearing.

4. Transmission mechanism (M) according to one of the preceding claims, characterized in that the lubricating fluid discharge passage (72, 72a) is a slot passing right through the thickness of the protective plate (70).

5. Transmission mechanism (M) according to the preceding claim, characterized in that the slot (72) is of elongated shape, for example of oblong shape.

6. Transmission mechanism (M) according to claim 4, characterized in that the slot (72) opens onto the outer periphery of the protective plate (70).

7. Transmission mechanism (M) according to one of the preceding claims, characterized in that the protective plate (70) partially covers the housing (40a, 40b), at least in an insertion zone (50) of the guide bearing formed on the housing.

8. Transmission mechanism (M) according to the preceding claim, characterized in that the protective plate (70) is axially supported on the casing, at least in the insertion zone (50) of the guide bearing.

9. Transmission mechanism (M) according to one of the preceding claims, characterized in that the casing (40a, 40b) comprises a groove (45) opening into the upper part of the cylindrical housing (41), the protective plate (70) at least partially covering the groove (45), and said lubricating fluid discharge passage (72, 72a) being arranged substantially opposite the groove (45) relative to the axis of rotation.

10. Transmission mechanism (M) according to one of the preceding claims, characterized in that the protective plate (70) is fixed on the non-rotating outer ring of the guide bearing and / or on the housing (40a, 40b).

11. Transmission mechanism (M) according to one of the preceding claims, characterized in that the protection plate (70) comprises a central bore into which the transmission shaft (10, 20, 30) is inserted.

12. Transmission mechanism (M) according to claim 7, characterized in that the insertion zone (50) of the guide bearing comprises a first substantially annular rim (51) which surrounds the cylindrical housing (41) and the guide bearing (100, 200, 300), the protective plate (70) covering with contact the first rim (51).

13. Transmission mechanism (M) according to the preceding claim, characterized in that the insertion zone (50) of the guide bearing also comprises a second substantially annular rim (52) arranged radially beyond the first rim (51) and a groove (53) arranged between the first and second rims, the protective plate (70) covering the insertion zone up to the second rim.

14. Transmission mechanism (M) according to one of the preceding claims, further comprising, housed in the casing (40a, 40b), a first transmission shaft (10) guided in rotation about a first axis of rotation (X1) by a first guide bearing (100a, 100b) and rotationally fixed to at least one drive pinion (11), a second transmission shaft (20) guided in rotation about a second axis of rotation (X2) by a second guide bearing (200a, 200b) and rotationally fixed to at least one intermediate pinion (21, 22), and a third transmission shaft (30) guided in rotation about a third axis of rotation (X3) by a third guide bearing (300a, 300b) and rotationally fixed to at least one driven pinion (31), the protective plate (70a) axially covers without contact the rolling elements of at least two guide bearings chosen from the first, the second and the third guide bearing.

15. Electric propulsion assembly comprising an electric motor (60) and a transmission mechanism (M) according to any one of the preceding claims, the transmission shaft (10, 20, 30) constituting an output shaft of the electric motor (60) or being rotationally integral with a drive shaft (63) of the electric motor.

Images