Propulsion unit and aircraft

Abstract

The invention relates to a propulsion unit and an aircraft, the propulsion unit comprising a propulsion system, at least one electric motor (44) positioned in a first outer region (ZE1), a transmission system (46) and coupling means comprising: a first coupling shaft (68), a second outer region (ZE2) coupled to the output (60) of the electric motor (44), passing through the transmission system (46) and having a first end (68.1) protruding into the second outer region (ZE2); a second coupling shaft (70) coupled to the input (52) of the drivetrain (46), passing through at least one wall of the drivetrain (46) and having a first end (70.1) protruding into a second outer region (ZE2); a coupling system (72) configured to rotationally couple the first end (68.1) of the first coupling shaft (68) and the first end (70.1) of the second coupling shaft (70) and positioned in the second outer region (ZE2). The aircraft comprises at least one such propulsion unit.

Description

Technical Field

[0001] The present application relates to a propulsion unit comprising at least one electric motor positioned on both sides of a transmission system and a coupling system, and furthermore the invention relates to an aircraft comprising at least one such propulsion unit. Background Art

[0002] According to the Figure 1 In one embodiment as seen in FIG. 1 , the aircraft 10 includes a fuselage 12, at least one wing 14 connected to the fuselage 12, and a propulsion unit 16 connected to the wing 14 and arranged on both sides of the fuselage 12. Figure 2 and Figure 3 As illustrated in , each propulsion unit 16 comprises a propeller 18 having an axis of rotation A18 .

[0003] For the remainder of the description, the longitudinal direction is parallel to the axis of rotation A18 of the propeller 18. The terms "front" and "rear" refer to the direction of the flow of air relative to the aircraft in flight, the air flowing from upstream to downstream in the longitudinal direction.

[0004] The electric type propulsion unit comprises a plurality of electric motors 20 and a transmission system 22 , such as, for example, a gearbox, configured to couple the electric motors 20 to the propellers 18 .

[0005] like Figure 3 As illustrated in the figure, the transmission system 22 includes a first housing 24 and at least one kinematic chain 26, the first housing 24 having a front wall F24 oriented toward the propeller 18 in the longitudinal direction and a rear wall F24' to which the electric motor 20 is fixed, the at least one kinematic chain 26 is positioned in the first housing 24, and the at least one kinematic chain 26 has at least one input portion 28 for each electric motor 20 and an output portion 30 in the form of an output shaft that passes through the front wall F24 so as to be connected to the propeller 18.

[0006] Each electric motor 20 has a second housing 32 including a bearing surface F32 fixed to the rear wall F24′ of the first housing 24, and an output shaft 34, relative to which the output shaft 34 projects and through which the output shaft 34 passes. The output shaft 34 is coupled to one of the inputs 28 of the kinematic chain 26 of the transmission system 22 by a coupling system 36 positioned in the first housing 24 of the transmission system 22.

[0007] According to one embodiment, each coupling system 36 includes a flywheel configured to adopt a coupled state and a decoupled state, in which the output shaft 34 of the corresponding electric motor 20 is rotationally coupled to the kinematic chain 26 of the transmission system 22 and transmits the rotational motion to the kinematic chain 26 of the transmission system 22, and in which, in the decoupled state, for example in the event of a fault, the output shaft 34 of the corresponding electric motor 20 is no longer coupled to the kinematic chain 26 of the transmission system 22 and no longer transmits any rotational motion to the kinematic chain 26 of the transmission system 22.

[0008] In this way, if an electric motor 20 is no longer functional and its output shaft 34 is blocked in rotation, the coupling system 36 makes it possible to isolate the kinematic chain 26 which remains operational and transmits the rotational movement of the other electric motor 20 to the propeller 18 .

[0009] The coupling system 36 requires more frequent maintenance operations than the other elements of the transmission system 22. For each maintenance operation, the transmission system 22 must be removed, which involves dismantling the electric motor 20, and the housing 24 of the transmission system 22 must be opened in order to access the coupling system 36. These various steps are relatively long, cumbersome and expensive. Summary of the invention

[0010] The present invention aims to remedy all or some of the disadvantages of the prior art. To this end, the subject of the invention is a propulsion unit comprising a propulsion system, at least one electric motor and a transmission system coupled to the propulsion system, the transmission system comprising a first transverse wall and a second transverse wall, the first transverse wall and the second transverse wall delimiting an inner area between the first transverse wall and the second transverse wall, a first outer area separated from the inner area by the first transverse wall and a second outer area separated from the inner area by the second transverse wall, the electric motor being connected to the first transverse wall and being positioned in the first outer area, and having an output coupled to an input of the transmission system positioned in the inner area by a coupling device.

[0011] According to the present invention, the coupling device comprises:

[0012] a first coupling shaft, which is coupled to the output of the electric motor, passes through the transmission system and has a first end projecting into the second outer region,

[0013] a second coupling shaft, which is coupled to the input of the transmission system, passes through at least the second transverse wall and has a first end projecting into the second outer region,

[0014] A coupling system configured to rotationally couple the first end of the first coupling shaft and the first end of the second coupling shaft and positioned in the second outer region.

[0015] According to the invention, the coupling system is positioned outside the transmission system. Therefore, it is no longer necessary to remove and dismantle the transmission system in order to perform maintenance operations on the coupling system, which enables the length of time between two maintenance operations on the transmission system to be increased. A more compact unit can be obtained by arranging the electric motor and the coupling system associated with the electric motor on both sides of the transmission system.

[0016] According to another feature, the second coupling shaft is hollow and is configured to receive the first coupling shaft.

[0017] According to another feature, the first coupling axis and the second coupling axis are coaxial.

[0018] According to another feature, the coupling system is positioned inside the second coupling shaft.

[0019] According to another feature, the coupling device comprises a plug configured to seal the first end of the second coupling shaft and connected to the second coupling shaft by a releasable connection.

[0020] According to a first embodiment, the electric motor comprises an output shaft passing through the transmission system, the output shaft and the first coupling shaft of the coupling device forming one and the same shaft.

[0021] According to a second embodiment, the electric motor comprises an output shaft positioned in the first outer region. In addition, the first coupling shaft of the coupling device and the output shaft of the electric motor are two separate shafts, the first coupling shaft comprises a second end, the second end is positioned in the first outer region, and the second end is coupled to the output shaft of the electric motor.

[0022] According to another feature, the second coupling shaft comprises a second end cooperating with the first transverse wall. In addition, the propulsion unit comprises a pivot connection comprising a first rotation guide inserted between a portion of the second coupling shaft and the second transverse wall, and a second rotation guide inserted between the second end of the second coupling shaft and the first transverse wall.

[0023] According to another feature, the propulsion system is positioned in the second outer region.

[0024] According to another feature, the coupling system is disengageable and is configured to adopt a coupled state, in which the output of the electric motor is rotationally coupled to the input of the transmission system and transmits a rotational movement to the input of the transmission system, and a decoupled state, in which the output of the electric motor is no longer coupled to the input of the transmission system and no longer transmits any rotational movement to the input of the transmission system.

[0025] According to another feature, the coupling system is configured to pass from the coupled state to the decoupled state as soon as the torque transmitted via the coupling system exceeds a given threshold or is no longer within a given range.

[0026] According to another feature, the connection system includes a flywheel configured to adopt a rotationally connected state and a disconnected state, and in the rotationally connected state, the first connection shaft is rotationally connected to the second connection shaft and transmits the rotational motion to the second connection shaft, and in the disconnected state, the first connection shaft is no longer rotationally connected to the second connection shaft and no longer transmits any rotational motion to the second connection shaft.

[0027] Another subject of the invention is an aircraft comprising at least one propulsion unit according to one of the preceding characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Other features and advantages will be found in the following description of the invention, which is provided by way of example only and with reference to the accompanying drawings, in which:

[0029] - Figure 1 This is a side view of the aircraft.

[0030] - Figure 2 is a side view of an electric propulsion unit illustrating an embodiment of the prior art,

[0031] - Figure 3 is a schematic cross section of a drive train and an electric motor of a propulsion unit, illustrating an embodiment of the prior art,

[0032] - Figure 4 is a schematic cross-section of a portion of a propulsion unit illustrating an embodiment,

[0033] - Figure 5 is a cross section of a portion of a drive train and coupling system of an electric motor illustrating an embodiment of the invention. DETAILED DESCRIPTION

[0034] According to the Figure 4In one embodiment seen in FIG. 4 , a propulsion unit 40 of the electric type comprises a propeller 42 having an axis of rotation A42 , a plurality of electric motors 44 and a transmission system 46 , such as, for example, a gearbox, configured to couple the electric motors 44 to the propeller 42 .

[0035] According to one application, the aircraft comprises at least one such propulsion unit 40. Naturally, the invention is not limited to this application. Whatever the application, the propulsion unit 40 of the electric type comprises a propulsion system such as, for example, a propeller, a plurality of electric motors 44 and a transmission system 46 configured to couple the electric motors 44 to the propulsion system.

[0036] According to the Figure 4 In the configuration seen in FIG. 4 , the transmission system 46 comprises a first housing 48 and at least one kinematic chain 50, the first housing 48 having in the longitudinal direction a front wall F48 oriented toward the propulsion system and a rear wall F48 'to which the electric motor 44 is fixed, the at least one kinematic chain 50 being positioned in the first housing 48 and having at least one input 52 for each electric motor 44 and an output 54 in the form of an output shaft passing through the front wall F48 in order to be coupled to the propulsion system. Figure 4 In the configuration seen in FIG. 4 , the input 52 of the transmission system 46 is a pinion. Naturally, the invention is not limited to this embodiment. Thus, the input 52 of the transmission system 46 may be a hollow shaft or any other element allowing coupling and transmission of rotational movement.

[0037] Each electric motor 44 comprises a second housing 56 having a first face 56.1 oriented towards the transmission 46 and a second face 56.2 opposite the first face 56.1 and the transmission 46. For each electric motor 44, the propulsion unit 40 comprises a connection element 58 enabling the electric motor 44 to be fixed to the first housing 48 of the transmission 46. By way of example, the connection elements 58 are screws passing through lugs of the second housing 56 fixed to the electric motor 44, the screws each being screwed into a threaded hole of the first housing 48 fixed to the transmission 46. Naturally, as for the connection elements 58, the invention is not limited to this embodiment.

[0038] According to one arrangement, the at least one electric motor 44 is positioned against a rear wall F48 ′ of the first housing 48 of the transmission system 46 and is connected to the rear wall F48 ′ by means of a connecting element 58 .

[0039] According to another arrangement, the at least one electric motor 44 is positioned against the front wall F48 of the first housing 48 of the transmission system 46 and is connected to the front wall F48 by means of a connecting element 58 .

[0040] Whatever the arrangement, the transmission system (more specifically, the first housing 48 of the transmission system) comprises a first transverse wall PT1 from the front wall F48 and the rear wall F48' and a second transverse wall PT2 from the front wall F48 and the rear wall F48' that is different from the first transverse wall PT1. The first transverse wall PT1 and the second transverse wall PT2 define an inner zone ZI located between the first transverse wall PT1 and the second transverse wall PT2, a first outer zone ZE1 separated from the inner zone ZI by the first transverse wall PT1, and a second outer zone ZE2 separated from the inner zone ZI by the second transverse wall PT2. At least one electric motor 44 is connected to the first transverse wall PT1 and positioned in the first outer zone ZE1, the electric motor 44 having an output 60 that is coupled to an input 52 of the transmission system 46 positioned in the inner zone ZI.

[0041] Each electric motor 44 includes an output 60 connected to the second housing 56 by a pivot connection 64 , such as, for example, an output shaft 62 having a pivot axis A62 .

[0042] According to one arrangement, the pivot axis A62 of the output shaft 62 is substantially parallel to the longitudinal direction. The first face 56.1 and the second face 56.2 are substantially perpendicular to the pivot axis A62 and are offset from each other in the longitudinal direction.

[0043] According to the Figure 4 , the output shaft 62 extends from the first face 56.1, passes through the transmission system 46, in particular the front wall F48 and the rear wall F48' of the first housing 48, and has a free end 62.1 that protrudes relative to the front wall F48 and is offset forward relative to the front wall F48.

[0044] According to the Figure 5 In another configuration seen in , the output shaft 62 is hollow and is offset rearwardly relative to the first face 56 . 1 of the second housing 56 and the rear wall F48 ′ of the first housing 48 .

[0045] Naturally, the output 60 of the electric motor 44 is not limited to these configurations. Thus, the output 60 of the electric motor 44 may be a pinion or any other element allowing coupling and transmission of rotational movement.

[0046] The propulsion unit 40 comprises at least one coupling device 66 connecting an output 60 of one of the electric motors 44 located in the first outer zone ZE1 and an input 52 of the transmission system 46 and configured to transmit a rotational movement between the output 60 and the input 52 .

[0047] The coupling device 66 comprises:

[0048] a first coupling shaft 68 which is coupled to the output 60 of the electric motor 44 , passes through the first housing 48 and has a first end 68 . 1 which projects into the second outer zone ZE2 ,

[0049] a second coupling shaft 70 coupled to the input 52 of the transmission 46 , passing through at least the second transverse wall PT2 of the first housing 48 and having a first end 70 . 1 protruding into the second outer zone ZE2 ,

[0050] A coupling system 72 which is configured to rotationally couple the first end 68 . 1 of the first coupling shaft 68 and the first end 70 . 1 of the second coupling shaft 70 and which is positioned in the second outer zone ZE2 .

[0051] According to one configuration, the propulsion unit 40 comprises a coupling device 66 for each electric motor 44 , whether the electric motor 44 is positioned in the first outer zone ZE1 or in the second outer zone ZE2 .

[0052] The coupling system 72 is disengageable and is configured to adopt a coupled state, in which the output 60 of the electric motor 44 is rotationally coupled to the input 52 of the transmission 46 and transmits a rotational movement to the input 52 of the transmission 46, and a decoupled state, in which, for example in the case of a fault, the output 60 of the electric motor 44 is no longer coupled to the input 52 of the transmission 46 and no longer transmits any rotational movement to the input 52 of the transmission 46. The coupling system 72 passes from the coupled state to the decoupled state as soon as the torque transmitted via the coupling system 72 exceeds a given threshold or is no longer within a given range, for example in the case of a fault.

[0053] In this way, for example, if the electric motor 44 coupled to the coupling system 72 is no longer functional and the output shaft 62 of the electric motor 44 is blocked in rotation, the coupling system 72 makes it possible to isolate the transmission system 46, which remains operational and transmits the rotational movement of the other electric motor to the propulsion system.

[0054] According to one embodiment, the connection system 72 includes a flywheel 72.1, which is configured to adopt a rotationally connected state and a disconnected state, and in the rotationally connected state, the first connecting shaft 68 is rotationally connected to the second connecting shaft 70 and transmits the rotational movement to the second connecting shaft 70, and in the disconnected state, for example in the event of a failure, the first connecting shaft 68 is no longer rotationally connected to the second connecting shaft 70 and no longer transmits any rotational movement to the second connecting shaft 70.

[0055] According to one configuration, the coupling system 72 comprises a first rotation guide 72.2 and a second rotation guide 72.3 positioned on both sides of a flywheel 72.1. The flywheel comprises a ring having an inner surface cooperating with the first coupling shaft 68 and an outer surface cooperating with the second coupling shaft 70, at least one of the inner and outer surfaces being coupled to the first coupling shaft 68 or the second coupling shaft 70 by friction.

[0056] Since the flywheel 72 . 1 is located outside the first housing 48 of the transmission system 46 , dust that may be generated by the friction coupling of the flywheel 72 . 1 does not contaminate the interior of the transmission system 46 , thereby limiting the risk of premature damage to components of the transmission system 46 .

[0057] In order to obtain a more compact unit, for at least one electric motor 44, the second coupling shaft 70 is hollow and configured to accommodate the first coupling shaft 68. According to one arrangement, the first coupling shaft 68 and the second coupling shaft 70 are coaxial.

[0058] According to one arrangement, the coupling system 72 is positioned inside the second coupling shaft 70 between the first end 68 . 1 of the first coupling shaft 68 and the first end 70 . 1 of the second coupling shaft 70 , which makes it possible to protect the coupling system.

[0059] Furthermore, the coupling device 66 comprises a plug 74 which is configured to seal the first end 70.1 of the second coupling shaft 70 and which is connected to the second coupling shaft 70 via a releasable connection. This embodiment makes it possible to increase the protection of the coupling system 72.

[0060] According to the Figure 4 In the first embodiment seen in FIG. 4 , the output shaft 62 of the electric motor 44 and the first coupling shaft 68 of the coupling device 66 form one and the same shaft. This shaft may be hollow or solid.

[0061] According to the Figure 5 In the second embodiment seen in FIG. 4 , the output shaft 62 of the electric motor 44 is positioned in the first outer zone ZE1 and is separate from the first coupling shaft 68 of the coupling device 66. According to this embodiment, the first coupling shaft 68 comprises a second end 68.2 which is positioned in the first outer zone ZE1 and which is coupled to the output shaft 62 of the electric motor 44.

[0062] According to one embodiment, the output shaft 62 of the electric motor 44 is hollow and configured to receive the second end 68.2 of the first coupling shaft 68. By way of example, the second end 68.2 and the output shaft 62 are splined. Other solutions for coupling the output shaft 62 of the electric motor 44 and the first coupling shaft 68 of the coupling device 66 can be envisaged.

[0063] According to one embodiment, the coupling means 66 comprise a pinion 76 fixed to and stationary relative to the second coupling shaft 70 , which cooperates with a pinion or ring gear of the input 52 of the transmission 46 .

[0064] According to one arrangement, the propulsion unit 40 includes a pivot connection 78 connecting the second coupling shaft 70 and the first housing 48 of the transmission system 46 .

[0065] According to one embodiment, the second coupling shaft 70 comprises a second end 70.2 cooperating with the first transverse wall PT1. In addition, the pivot connection 78 comprises a first rotation guide 78.1, such as a bearing, for example, and a second rotation guide 78.2, such as a bearing, for example, which is inserted between a portion 70.3 of the second coupling shaft 70 and the second transverse wall PT2, and a second rotation guide 78.2, such as a bearing, which is inserted between the second end 70.2 of the second coupling shaft 70 and the first transverse wall PT1.

[0066] According to a first configuration, all the electric motors 44 are positioned against the rear wall F48 ′ of the transmission 46 and each coupling system 72 of all the electric motors 44 is positioned upstream of the front wall F48 of the transmission 46 in the second outer zone ZE2 in which the propulsion system is positioned.

[0067] According to another configuration, at least one electric motor 44 is positioned against the front wall F48 of the transmission system 46 and the coupling system 72 associated with said at least one electric motor 44 is positioned downstream of the rear wall F48 ′.

[0068] Whatever the embodiment, the coupling system 72 is positioned outside the first housing 48 of the transmission system 46. Thus, it is no longer necessary to remove the transmission system 46 and dismantle the transmission system 46 in order to perform maintenance operations on the coupling system 72, which allows the length of time between two maintenance operations on the transmission system 46 to be increased. A more compact unit can be obtained by arranging the electric motor 44 and the coupling system 72 associated with the electric motor 44 on both sides of the transmission system 46. In addition, the coupling system 72 is more accessible when the coupling system 72 is positioned upstream of the transmission system, thereby facilitating maintenance operations.

Claims

1. A propulsion unit, comprising a propulsion system, at least one electric motor (44), a coupling device (66) and a transmission system (46) coupled to the propulsion system, the transmission system (46) comprising a first transverse wall (PT1) and a second transverse wall, the first transverse wall (PT1) and the second transverse wall delimiting an inner zone (ZI) between the first transverse wall (PT1) and the second transverse wall (PT2), a first outer zone (ZE1) separated from the inner zone (ZI) by the first transverse wall (PT1) and a second outer zone (ZE2) separated from the inner zone (ZI) by the second transverse wall (PT2), the electric motor (44) being connected to the first transverse wall (PT1) and being positioned in the first outer zone (ZE1), and the electric motor (44) having an output (60) coupled to an input (52) of the transmission system (46) positioned in the inner zone (ZI) by the coupling device (66); wherein The coupling device (66) comprises: a first coupling shaft (68) which is coupled to the output (60) of the electric motor (44), passes through the transmission system (46) and has a first end (68.1) which projects into the second outer region (ZE2), a second coupling shaft (70) which is coupled to the input (52) of the transmission system (46), passes through at least the second transverse wall (PT2) and has a first end (70.1) which projects into the second outer zone (ZE2), A coupling system (72) is configured to rotationally couple the first end (68.1) of the first coupling shaft (68) and the first end (70.1) of the second coupling shaft (70), and the coupling system (72) is positioned in the second outer zone (ZE2).

2. Propulsion unit according to the preceding claim, wherein: The second coupling shaft (70) is hollow and configured to receive the first coupling shaft (68).

3. Propulsion unit according to the preceding claim, wherein: The first coupling shaft (68) and the second coupling shaft (70) are coaxial.

4. The propulsion unit according to one of claims 2 to 3, wherein: The coupling system (72) is positioned inside the second coupling shaft (70).

5. Propulsion unit according to the preceding claim, wherein: The coupling device (66) comprises a plug (74) which is configured to seal the first end (70.1) of the second coupling shaft (70) and which is connected to the second coupling shaft (70) by a releasable connection.

6. Propulsion unit according to one of the preceding claims, wherein The electric motor (44) comprises an output shaft (62) passing through the transmission system (46), and wherein the output shaft (62) and the first coupling shaft (68) of the coupling device (66) form one and the same shaft.

7. The propulsion unit according to one of claims 1 to 5, wherein: The electric motor (44) comprises an output shaft (62) positioned in the first outer zone (ZE1), and wherein the first coupling shaft (68) of the coupling device (66) and the output shaft (62) of the electric motor (44) are two separate shafts, the first coupling shaft (68) comprising a second end (68.2), the second end (68.2) being positioned in the first outer zone (ZE1) and the second end (68.2) being coupled to the output shaft (62) of the electric motor (44).

8. Propulsion unit according to one of the preceding claims, wherein The second connecting shaft (70) includes a second end (70.2) that cooperates with the first transverse wall (PT1), and wherein the propulsion unit (40) includes a pivot connection (78), the pivot connection (78) includes a first rotation guide (78.1) and a second rotation guide (78.2), the first rotation guide (78.1) is inserted between a portion (70.3) of the second connecting shaft (70) and the second transverse wall (PT2), and the second rotation guide (78.2) is inserted between the second end (70.2) of the second connecting shaft (70) and the first transverse wall (PT1).

9. The propulsion unit according to one of the preceding claims, wherein: The propulsion system is positioned in the second outer zone (ZE2).

10. The propulsion unit according to one of the preceding claims, wherein: The coupling system (72) is disengageable and is configured to adopt a coupled state, in which the output (60) of the electric motor (44) is rotationally coupled to the input (52) of the transmission system (46) and transmits rotational motion to the input (52) of the transmission system (46), and a decoupled state, in which the output (60) of the electric motor (44) is no longer coupled to the input (52) of the transmission system (46) and no longer transmits any rotational motion to the input (52) of the transmission system (46).

11. Propulsion unit according to the preceding claim, wherein: The coupling system (72) is configured to transition from the coupled state to the decoupled state once the torque transmitted via the coupling system (72) exceeds a given threshold or is no longer within a given range.

12. Propulsion unit according to one of the preceding claims, wherein The coupling system (72) comprises a flywheel (72.1), which is configured to adopt a rotationally coupled state and a decoupled state, and in the rotationally coupled state, the first coupling shaft (68) is rotationally coupled to the second coupling shaft (70) and transmits rotational motion to the second coupling shaft (70), and in the decoupled state, the first coupling shaft (68) is no longer rotationally coupled to the second coupling shaft (70) and no longer transmits any rotational motion to the second coupling shaft (70).

13. An aircraft comprising at least one propulsion unit according to one of the preceding claims.

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