Engine assembly comprising at least one rotational guidance system and at least one lubrication system using a Venturi effect

Abstract

Motor assembly comprising at least one rotational guidance system and at least one lubrication system using a Venturi effect The invention relates to a motor assembly comprising: an electric motor (42) which comprises a rotational guidance system (52) comprising first and second bearings (52.1, 52.2) positioned on either side of the rotor (48) of the electric motor, respectively in first and second annular housings (72.1, 72.2), a main lubrication circuit (78) which comprises at least one passage section reduction (98), a secondary lubrication circuit (86, 90) which comprises at least one downstream section (94), connected to at least one of the annular housings (72.1, 72.2), opening near and upstream of the passage section reduction (98) of the main lubrication circuit (78).This solution allows, thanks to a Venturi effect, to obtain suction and circulation of the lubricant in the secondary lubrication circuit, without a pump. Figure 2.

Description

Title of the invention: Engine assembly comprising at least one rotational guidance system and at least one lubrication system using a Venturi effect

[0001] The present application relates to an engine assembly comprising at least one rotational guidance system and at least one lubrication system using a Venturi effect.

[0002] According to an embodiment visible in [Fig.l], a motor assembly 10 comprises an electric motor 12 comprising a structure 14, a stator 16 fixed relative to the structure 14 and connected to the latter, a rotor 18 positioned inside the stator 16 as well as a shaft 22 secured to the rotor 18 and connected to the structure 14 by a rotational guidance system 20. The shaft 22 and the rotor 18 are coaxial and have a motor axis A12. The structure 14 is delimited by first and second transverse walls 14.1, 14.2 (substantially perpendicular to the motor axis A12), the stator 16, the rotor 18 and the shaft 22 being positioned between the first and second transverse walls 14.1, 14.2. The shaft 22 extends between first and second ends 22.1, 22.2 close respectively to the first and second transverse walls 14.1, 14.2.

[0003] The rotational guidance system 20 comprises first and second bearings 20.1, 20.2, such as rolling bearings for example, positioned near the first and second ends 22.1, 22.2 of the shaft 22, each interposed between the structure 14 and the shaft 22. Each bearing 20.1, 20.2 may be composed of one or more bearing(s).

[0004] According to a first configuration visible in [Fig.l], the shaft 22 is hollow and the motor assembly 10 comprises an output shaft 24, partially positioned in the hollow shaft 22, which extends between first and second ends 24.1, 24.2, the first end 24.1 of the output shaft 24 being positioned projecting relative to the first transverse wall 14.1 of the structure 14 of the electric motor 12 and connected to a load 26, such as a propeller or a gearbox for example, the second end 24.2 of the output shaft 24 and the second end 22.2 of the hollow shaft 22 being located approximately in the same transverse plane. According to one embodiment, the first end 24.1 of the output shaft 24 is connected to the load 26 by a rigid connection. Additionally, the second end 24.2 of the output shaft 24 and the second end 22.2 of the hollow shaft 22 are connected by a coupling system 28.

[0005] According to a second configuration, the shaft 22 is solid and its first end 22.1 is connected directly or indirectly via an output shaft to a load 26, such as a propeller or a gearbox for example.

[0006] According to one arrangement, the load 26 is positioned against the first transverse wall 14.1 and connected to the structure 14.

[0007] To increase reliability and limit the risks of premature wear, the electric motor 12 and the load 26 each have their own lubrication system 30. Each of them comprises a lubricant reservoir 32, a lubrication circuit 34 configured to convey the lubricant from the lubricant reservoir to the various components to be lubricated as well as at least one heat exchanger to cool the lubricant.

[0008] In the electric motor 12, the lubrication system is designed in particular to lubricate the first and second bearings 20.1, 20.2 of the rotational guidance system 20. In order not to cause an excessive rise in temperature, the first and second bearings 20.1, 20.2 must not be immersed in the lubricant. However, the flow rate of lubricant passing through the first and second bearings 20.1, 20.2 must be sufficiently high to cool them properly.

[0009] According to a first configuration, the circulation of the lubricant in the lubrication circuit 34 is obtained by gravity. In this case, the conduits of the lubrication circuit 34 must have a large section to obtain a high flow rate up to the second bearing 20.2 positioned at a distance from the load 26 and therefore from the heat exchanger provided for cooling the lubricant of the lubrication system dedicated to the load 26. This first configuration is not satisfactory because such conduits are difficult to integrate into the electric motor 12 and impact the mass and volume of the latter.

[0010] According to a second configuration, the lubrication circuit 34 comprises a pump in order to generate a flow of lubricant suitable for the first and second bearings 20.1, 20.2. This second configuration is not satisfactory because such a pump is difficult to integrate into an electric motor 12 and impacts the mass and volume of the latter.

[0011] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0012] For this purpose, the invention relates to a motor assembly comprising: a. an electric motor which comprises a structure having first and second transverse walls, a stator fixed relative to the structure, a rotor coaxial with the stator, a shaft secured to the rotor and a rotational guidance system connecting the structure and the shaft, b. a load connected to the first transverse wall of the structure and coupled to the shaft, c. the rotational guidance system comprising first and second bearings positioned on either side of the rotor respectively in first and second annular housings, the first annular housing being positioned close to the load, the second annular housing being distant from the load, d. a main lubrication circuit and a secondary lubrication circuit, configured to lubricate at least one annular housing among the first and second annular housings, comprising at least one downstream section which extends between first and second ends, the first end opening into the annular housing.

[0013] According to the invention, the main lubrication circuit comprises at least one passage section reduction. In addition, the second end of the downstream section opens close to and upstream of the passage section reduction of the main lubrication circuit.

[0014] This solution makes it possible, thanks to a Venturi effect, to obtain suction and circulation of the lubricant in the secondary lubrication circuit, without a pump, which facilitates the integration of the secondary lubrication circuit in the electric motor.

[0015] According to another characteristic, the main lubrication circuit comprises an upstream section upstream of the passage section reduction, a convergent positioned between the upstream section and the passage section reduction as well as a divergent positioned downstream of the passage reduction, the passage section reduction having a passage section less than a predetermined value.

[0016] According to another characteristic, the second end of the downstream section opens into the convergent.

[0017] According to another characteristic, the reduction in passage section has a passage section substantially identical to that of the downstream section.

[0018] According to another characteristic, the first end of the downstream section opens at a low point of the first or second annular housing.

[0019] According to another characteristic, the first or second annular housing comprises a hollow shape at the low point.

[0020] According to another characteristic, the main lubrication circuit comprises: a. at least one enclosure, in which the stator is positioned, comprising a first end oriented towards the first transverse wall and a second end oriented towards the second transverse wall, b. an upstream annular collector communicating with the first end of the (or different) enclosure(s), c. a downstream annular collector communicating with the second end of the (or different) enclosure(s), d. at least one return conduit communicating with the downstream annular collector and opening at the level of the first transverse wall.

[0021] According to another characteristic, the reduction in passage section is located at the level of the return duct.

[0022] According to another characteristic, the electric motor comprises at least one lubrication system for the first bearing comprising at least one upstream section which extends between a first end opening into the upstream annular collector and a second end opening into the first annular housing as well as at least one lubrication system for the second bearing comprising at least one upstream section which extends between a first end opening into the downstream annular collector and a second end opening into the second annular housing.

[0023] According to another characteristic, the lubrication system of the first or second bearing comprises several upstream sections, oriented radially around the first or second annular housing, connecting the latter and the upstream or downstream annular collector.

[0024] According to another characteristic, the first annular housing communicates directly or indirectly with a circuit of a load lubrication system.

[0025] According to another characteristic, the main lubrication circuit is connected to a circuit of a load lubrication system.

[0026] The invention also relates to an aircraft propulsion assembly comprising at least one engine assembly according to one of the preceding characteristics.

[0027] Other characteristics and advantages will emerge from the description of the invention which follows, a description given by way of example only, with reference to the appended drawings, among which:

[0028] [Fig. 1] is a schematic section of an engine assembly illustrating a first embodiment of the prior art, and

[0029] [Fig.2] is a schematic section of an engine assembly illustrating an embodiment according to the invention.

[0030] According to an embodiment visible in [Fig.2], a motor assembly 40 comprises an electric motor 42 comprising a structure 44, a stator 46 fixed relative to the structure 44 and connected to the latter, a rotor 48 coaxial with the stator 46, a shaft 50 secured to the rotor 48 as well as a rotational guidance system 52 connecting the structure 44 and the shaft 50.

[0031] The shaft 50 and the rotor 48 are coaxial and have a motor axis A42. According to one embodiment, the stator 46 comprises several coils.

[0032] For the remainder of the description, an axial direction is parallel to the motor axis A42. A transverse plane is perpendicular to the motor axis A42. A radial direction is perpendicular to the motor axis A42. In operation, the axial direction is generally horizontal. The terms low / high or lower / upper refer to gravity.

[0033] According to one embodiment, the structure 44 comprises a tubular body 44.1 as well as first and second transverse walls 44.2, 44.3 positioned at each end of the tubular body 44.1, the tubular body 44.1, the first and second transverse walls 44.2, 44.3 being connected to each other.

[0034] Of course, the invention is not limited to this embodiment for the structure 44.

[0035] The shaft 50 extends between first and second ends 50.1, 50.2 close respectively to the first and second transverse walls 44.2, 44.3. According to one arrangement, the first and second ends 50.1, 50.2 of the shaft 50 pass respectively through the first and second transverse walls 44.2, 44.3 of the structure 44.

[0036] The rotational guidance system 52 comprises first and second bearings 52.1, 52.2, such as rolling bearings for example, positioned near or at the first and second ends 50.1, 50.2 of the shaft 50, on either side of the rotor 48. Each bearing 52.1, 52.2 may be composed of one or more bearing(s).

[0037] For each of the first and second bearings 52.1, 52.2, the rotational guidance system 52 comprises outer and inner cylindrical walls 54.1, 54.2 secured respectively to the structure 44 and to the shaft 50. Each of the first and second bearings 52.1, 52.2 of the rotational guidance system 52 comprises an outer part 56.1 in contact with the outer cylindrical wall 54.1 as well as an inner part 56.2 in contact with the inner cylindrical wall 54.2.

[0038] According to one embodiment, the motor assembly 40 comprises, for each first or second bearing 52.1, 52.2, an internal seal 58.1, 58.2 interposed between the first or second bearing 52.1, 52.2 and the rotor 48, in contact simultaneously with the outer and inner cylindrical walls 54.1, 54.2. A first internal seal 58.1 is positioned between the first bearing 52.1 and the rotor 48. A second internal seal 58.2 is positioned between the second bearing 52.2 and the rotor 48.

[0039] According to a first configuration, the shaft 50 is hollow and the motor assembly 40 comprises an output shaft 60, which extends between first and second ends 60.1, 60.2, partially positioned in the hollow shaft 50, the first end 60.1 of the output shaft 60 being positioned projecting relative to the first transverse wall 44.2 of the structure 44 of the electric motor 42 and configured to be connected to a load 62, the second end 60.2 of the output shaft 60 and the second end 50.2 of the hollow shaft 50 being located approximately in the same transverse plane.

[0040] The motor assembly 40 comprises at least one coupling system 64 connecting the hollow shaft 50 and the output shaft 60. According to one embodiment, the coupling system 64 connects, directly or indirectly, the second ends 50.2, 60.2 of the hollow shaft 50 and the output shaft 60.

[0041] According to an arrangement visible in [Fig.2], the second end 50.2 of the hollow shaft 50 is blind. According to another arrangement, the second end 50.2 of the hollow shaft 50 is open.

[0042] According to one embodiment, the second transverse wall 44.3 of the structure 44 comprises an orifice 66 positioned in the extension of the second end 50.2 of the hollow shaft 50 to make the coupling system 64 accessible when the second end 50.2 of the hollow shaft 50 is open.

[0043] In addition, the motor assembly 40 comprises a plug 68 configured to close the orifice 66, fixing elements 68.1 connecting the plug 68 and the second transverse wall 44.3 as well as at least one sealing gasket inserted between the second transverse wall 44.3 and the plug 68.

[0044] According to one embodiment, the motor assembly 40 comprises an external seal 70 in simultaneous contact with the hollow shaft 50 and the plug 68 or the second transverse wall 44.3 of the structure 44.

[0045] According to a second configuration, the shaft 50 is solid and directly or indirectly connected to the load 62.

[0046] Regardless of the configuration, the shaft 50 is directly or indirectly coupled to a load 62.

[0047] The load 62 is positioned against the first transverse wall 44.2 of the structure 44 and connected to the latter by at least one fixing element 62.1.

[0048] According to one application, the load 62 is a propeller and / or a gearbox of a propulsion assembly of an aircraft. Thus, an aircraft propulsion assembly comprises at least one engine assembly 40 as illustrated in [Fig.2].

[0049] Whatever the embodiment, the motor assembly 40 comprises a first annular housing 72.1, in which the first bearing 52.1 is positioned, positioned close to the load 62, as well as a second annular housing 72.2 in which the second bearing 52.2 is positioned, distant from the load 62.

[0050] According to one embodiment, the first annular housing 72.1 is delimited by the first transverse wall 44.2 of the structure 44, the shaft 50 and the first internal seal 58.1. The first annular housing 72.1 is open towards the load 62. The second annular housing 72.2 is delimited by the second transverse wall 44.3 of the structure 44, the shaft 50, the second internal seal 58.2 and the external seal 70.

[0051] According to one embodiment, the motor assembly 40 comprises at least one sensor 74 configured to determine at least one characteristic of the rotational movement of the shaft 50 and / or the output shaft 60. By way of example, the sensor 74 is a resolver configured to determine the angular position of the shaft 50 and / or the shaft output 60. According to one configuration, the sensor 74 is positioned between the plug 68 secured to the structure 44 and the shaft 50. According to one arrangement, the sensor 74 is positioned between the external seal 70, the shaft 50 and the plug 68.

[0052] Of course, the invention is not limited to this type of sensor 74 or to this positioning for the sensor 74.

[0053] According to one embodiment, the load 62 comprises at least one load lubrication system 76 comprising a lubricant reservoir, a lubrication circuit configured to convey the lubricant from the lubricant reservoir to the various components to be lubricated as well as at least one pump to circulate the lubricant in the lubrication circuit.

[0054] The electric motor 42 comprises at least one stator lubrication circuit 78 configured to lubricate the stator 46. According to one embodiment, the stator lubrication circuit 78 comprises at least one enclosure 80, in which the stator 46 and its coils are positioned, comprising a first end 80.1 oriented towards the first transverse wall 44.2 and a second end 80.2 oriented towards the second transverse wall 44.3.

[0055] According to one arrangement, the stator lubrication circuit 78 comprises a single annular enclosure 80 which extends over the entire circumference of the structure 44.

[0056] According to another arrangement, the stator lubrication circuit 78 comprises several enclosures 80 distributed around the circumference of the structure 44. In addition, the electric motor 42 comprises an upstream annular collector 82.1 communicating with the first end 80.1 of the (or different) enclosure(s) 80 as well as a downstream annular collector 82.2 communicating with the second end 80.2 of the (or different) enclosure(s) 80. According to one embodiment, the upstream and downstream annular collectors 82.1, 82.2 are positioned at the first and second transverse walls 44.2, 44.3 and extend over the entire circumference of said walls. In addition, each enclosure 80 extends from the first transverse wall 44.2 to the second transverse wall 44.3. According to this embodiment, the upstream and downstream annular collectors 82.1, 82.2 communicate directly with the different enclosures 80.

[0057] According to one configuration, the upstream annular collector 82.1 communicates with a lubricant reservoir. In addition, the stator lubrication circuit 78 comprises at least one return conduit 84 communicating with the downstream annular collector 82.2 and opening at the first transverse wall 44.2. According to this configuration, the lubricant flows into the upstream annular collector 82.1, into the enclosures 80, into the downstream annular collector 82.2 then into the return conduit 84.

[0058] According to one arrangement, this return conduit 84 is positioned in the structure 44. According to one embodiment, the return conduit 84 comprises a first section 84.1 of plugging into the downstream annular collector 82.2 and positioned in the second transverse wall 44.3, a second section 84.2 positioned in the extension of the first section 84.1 and passing through the tubular body 44.1 as well as a third section 84.3 positioned in the extension of the second section 84.2 and passing through the first transverse wall 44.2.

[0059] According to one embodiment, the upstream annular collector 82.1 and the return conduit 84 are connected to the circuit of the load lubrication system 76. This embodiment makes it possible to share the equipment of the electric motor 42 and the load 62.

[0060] According to one configuration, the upstream and downstream annular collectors 82.1, 82.2, the enclosures 80 and the return conduit 84 have large passage sections which guarantee a high flow rate.

[0061] Of course, the invention is not limited to this embodiment for the stator lubrication circuit 78. According to a preferred configuration, the latter comprises at least one circuit connected to the load lubrication system 76, which makes it possible to share the equipment of the electric motor 42 and the load 62. This also makes it possible to simplify the integration of the stator lubrication circuit 78 in the electric motor 42 insofar as this lubrication circuit does not include a pump and / or heat exchanger for example.

[0062] The electric motor 42 comprises at least one lubrication circuit of the first bearing 86, configured to lubricate the first annular housing 72.1, comprising at least one upstream section 88 which extends between first and second ends 88.1, 88.2, the second end 88.2 of the upstream section 88 opening into the first annular housing 72.1. This upstream section 88 is positioned in the first transverse wall 44.2.

[0063] According to one configuration, the lubrication circuit of the first bearing 86 is connected to the circuit of the load lubrication system 76 via in particular the stator lubrication circuit 78. According to one arrangement, the first end 88.1 of the upstream section 88 is directly or indirectly connected to the circuit of the load lubrication system 76 and / or the first annular housing 72.1 communicates directly or indirectly with the circuit of the load lubrication system 76. According to this configuration, the lubricant of the load lubrication system 76 is used to lubricate the first annular housing 72.1 in which the first bearing 52.1 is positioned, which makes it possible to share the equipment of the electric motor 42 and the load 62.

[0064] According to one embodiment, the first end 88.1 of the upstream section 88 is connected to the stator lubrication circuit 78 and more particularly to the upstream annular collector 82.1. This upstream section 88 has a clearly defined passage section lower than that(s) of the stator lubrication circuit 78. According to one arrangement, the lubrication circuit of the first bearing 86 comprises several upstream sections 88, oriented radially around the first annular housing 72.1, connecting the latter and the upstream annular collector 82.1. The fact that the first annular housing 72.1 is supplied by several upstream sections 88 themselves supplied by the stator lubrication circuit 78 which has large passage sections makes it possible to ensure optimal lubrication of the first bearing 52.1 over its entire periphery.

[0065] The electric motor 42 comprises at least one lubrication circuit of the second bearing 90, configured to lubricate the second annular housing 72.2 in which the second bearing 52.2 is positioned, which comprises at least one upstream section 92 extending between first and second ends 92.1, 92.2, the second end 92.2 of the upstream section 92 opening into the second annular housing 72.2. This upstream section 92 is positioned in the second transverse wall 44.3.

[0066] According to one embodiment, the first end 92.1 of the upstream section 92 is connected to the stator lubrication circuit 78 and more particularly to the upstream annular collector 82.1. This upstream section 92 has a passage section that is significantly smaller than that(s) of the stator lubrication circuit 78. According to one arrangement, the lubrication circuit of the second bearing 90 comprises several upstream sections 92, oriented radially around the second annular housing 72.2, connecting the latter and the downstream annular collector 82.2. The fact that the second annular housing 72.2 is supplied by several upstream sections 92 themselves supplied by the stator lubrication circuit 78 which has large passage sections makes it possible to ensure optimal lubrication of the second bearing 52.2 over its entire periphery.

[0067] According to one configuration, the lubrication circuit of the second bearing 90 comprises at least one downstream section 94 which extends between first and second ends 94.1, 94.2, the first end 94.1 opening into the second annular housing 72.2.

[0068] According to one arrangement, the first end 94.1 of the downstream section 94 opens at a low point 96 of the second annular housing 72.2 to collect the lubricant by gravity. According to one configuration, the second annular housing 72.2 comprises a hollow shape, at the low point 96 of the second annular housing 72.2 at which the first end 94.1 of the downstream section 94 opens, to promote the collection of the lubricant.

[0069] According to one configuration, the lubrication circuit of the first bearing 86 also comprises at least one downstream section which extends between first and second ends, the first end opening into the first annular housing 72.1, in particular at a low point of the latter. Like the second annular housing 72.1, the first annular housing 72.1 may comprise a shape in hollow at which the first end of the downstream section opens.

[0070] According to one embodiment, the downstream section 94 has a passage section that is significantly smaller than that(s) of the stator lubrication circuit 78.

[0071] According to a feature of the invention, the stator lubrication circuit 78 comprises a passage section reduction 98 as well as an upstream section 100 upstream of the passage section reduction 98. The upstream section 100 and the passage section reduction 98 are substantially coaxial. According to one embodiment, the passage section reduction has a passage section less than a predetermined value depending for example on the desired flow rate. By way of example, the passage section of the passage section reduction is less than half that of the upstream section 100, preferably less than 20% of that of the upstream section 100. According to one arrangement, the stator lubrication circuit 78 comprises a convergent 102 between the upstream section 100 and the passage section reduction 98 as well as a divergent downstream of the passage reduction 98.

[0072] According to one arrangement, the passage section reduction 98 has a section substantially identical to that of the downstream section 94. According to one embodiment, the passage section reduction 98 is provided at the level of the return conduit 84, more particularly at the level of the first section 84.1 of the return conduit 84.

[0073] In addition to the passage section reduction 98, the second end 94.2 of the downstream section 94 opens near the passage section reduction 98, upstream of the latter, in the convergent 102. The second end 94.2 of the downstream section 94 and the passage section reduction 98 are substantially coaxial. By near, it is meant that the second end 94.2 of the downstream section 94 is spaced from the passage section reduction 98 by a distance of less than 20 mm.

[0074] The combination of the reduction in passage section 98 and the positioning of the second end 94.2 of the downstream section 94 just upstream of the reduction in passage section 98 causes, by Venturi effect, a suction of the lubricant which circulates in the lubrication circuit of the second bearing 90. This solution makes it possible to obtain a circulation of the lubricant in the lubrication circuit of the second bearing 90, without a pump, in an area remote from the load 62.

[0075] Of course, the invention is not limited to this embodiment. The electric motor 42 comprises a main lubrication circuit, such as the stator lubrication circuit 78 for example, as well as at least one secondary lubrication circuit 90 configured to lubricate at least one annular housing, among the first and second annular housings 72.1, 72.2, comprising at least one downstream section 94 which extends between first and second ends 94.1, 94.2, the first end 94.1 opening into the annular housing 72.1, 72.2. According to a feature of the invention, the main lubrication circuit comprises at least one passage section reduction 98, the second end 94.2 of the downstream section 94 opening near and upstream of said passage section reduction 98. This solution makes it possible, thanks to a Venturi effect, to obtain suction and circulation of the lubricant in the secondary lubrication circuit, without a pump, which facilitates the integration of the secondary lubrication circuit in the electric motor.

[0076] According to a preferred mode of operation, the lubricant circulates at a high pressure in the main lubrication circuit and at a low pressure in the secondary lubrication circuit.

[0077] According to a preferred configuration, the main lubrication circuit is connected to the circuit of the lubrication system of the load 76, which makes it possible to share the equipment of the electric motor 42 and the load 62.

Claims

Claims

1. Engine assembly comprising: a. an electric motor (42) which comprises a structure (44) having first and second transverse walls (44.2, 44.3), a stator (46) fixed relative to the structure (44), a rotor (48) coaxial with the stator (46), a shaft (50) secured to the rotor (48) as well as a rotational guidance system (52) connecting the structure (44) and the shaft (50), b. a load (62) connected to the first transverse wall (44.2) of the structure (44) and coupled to the shaft (50), c. the rotational guidance system (52) comprising first and second bearings (52.1, 52.2) positioned on either side of the rotor (48) respectively in first and second annular housings (72.1, 72.2), the first annular housing (72.1) being positioned close to the load (62), the second annular housing (72.2) being distant from the load (62), d. a main lubrication circuit (78) and a secondary lubrication circuit (86, 90), configured to lubricate at least one annular housing among the first and second annular housings (72.1, 72.2), comprising at least one downstream section (94) which extends between first and second ends (94.1, 94.2), the first end (94.1) opening into the annular housing (72.1, 72.2), e. characterized in that the main lubrication circuit (78) comprises at least one passage section reduction (98) and in that the second end (94.2) of the downstream section (94) opens near and upstream of the passage section reduction (98) of the main lubrication circuit (78).

2. Engine assembly according to claim 1, characterized in that the main lubrication circuit (78) comprises an upstream section (100) upstream of the passage section reduction (98), a convergent (102) positioned between the upstream section (100) and the passage section reduction (98) as well as a divergent positioned downstream of the passage reduction (98), the passage section reduction (98) having a passage section less than a predetermined value.

3. Engine assembly according to the preceding claim, characterized in that the second end (94.2) of the downstream section (94) opens into the convergent (102).

4. Engine assembly according to one of the preceding claims, characterized in that the passage section reduction (98) has a passage section substantially identical to that of the downstream section (94).

5. Engine assembly according to one of the preceding claims, characterized in that the first end (94.1) of the downstream section (94) opens at a low point (96) of the first or second annular housing (72.1, 72.2).

6. Engine assembly according to the preceding claim, characterized in that the first or second annular housing (72.1, 72.2) comprises a hollow shape at the low point (96).

7. Motor assembly according to one of the preceding claims, characterized in that the main lubrication circuit (78) comprises: a. at least one enclosure (80), in which the stator (46) is positioned, comprising a first end (80.1) oriented towards the first transverse wall (44.2) and a second end (80.2) oriented towards the second transverse wall (44.3), b. an upstream annular collector (82.1) communicating with the first end (80.1) of the at least one enclosure (80), c. a downstream annular collector (82.2) communicating with the second end (80.2) of the at least one enclosure (80), d. at least one return conduit (84) communicating with the downstream annular collector (82.2) and opening at the first transverse wall (44.2).

8. Engine assembly according to the preceding claim, characterized in that the reduction in passage section (98) is located at the level of the return duct (84).

9. Motor assembly according to one of claims 7 to 8, characterized in that the electric motor (42) comprises at least one lubrication circuit of the first bearing (86) comprising at least one upstream section (88) which extends between a first end (88.1) opening into the upstream annular collector (82.1) and a second end (88.2) de- opening into the first annular housing (72.1) as well as at least one lubrication circuit (90) of the second bearing (52.2) comprising at least one upstream section (92) which extends between a first end (92.1) opening into the downstream annular collector (82.2) and a second end (92.2) opening into the second annular housing (72.2).

10. Engine assembly according to the preceding claim, characterized in that the lubrication circuit (86, 90) of the first or second bearing (52.1, 52.2) comprises several upstream sections (88, 92), oriented radially around the first or second annular housing (72.1, 72.2), connecting the latter and the upstream or downstream annular collector (82.1, 82.2).

11. Engine assembly according to one of the preceding claims, characterized in that the first annular housing (72.1) communicates directly or indirectly with a circuit of a load lubrication system (76).

12. Engine assembly according to one of the preceding claims, characterized in that the main lubrication circuit (78) is connected to a circuit of a load lubrication system (76).

13. Aircraft propulsion assembly comprising at least one engine assembly according to one of the preceding claims.

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