Propulsion assembly comprising at least one electric motor and a coupling system positioned on either side of a transmission system

Abstract

Propulsion assembly comprising at least one electric motor and a coupling system positioned on either side of a transmission system. The invention relates to a propulsion assembly comprising a propulsion system, at least one electric motor (44) positioned in a first external zone (ZE1), a transmission system (46) and a coupling device which includes: a first coupling shaft (68) coupled to an output (60) of the electric motor (44), passing through the transmission system (46) and having a first end (68.1) projecting into a second external zone (ZE2), a second coupling shaft (70) coupled to an input (52) of the transmission system (46), passing through at least one wall of the transmission system (46) and having a first end (70.1) projecting into the second external zone (ZE2), a coupling system (72) configured to rotationally couple the first ends (68.1, 70.1) of the first and second coupling shafts (68 70), positioned in the second outer zone (ZE2). The invention also relates to an aircraft comprising at least one such propulsion assembly. Figure 4.

Description

Title of the invention: Propulsion assembly comprising at least one electric motor and a coupling system positioned on either side of a transmission system

[0001] The present application relates to a propulsion assembly comprising at least one electric motor and a coupling system positioned on either side of a transmission system and to an aircraft comprising at least one such propulsion assembly.

[0002] According to an embodiment visible in [Fig. 1], an aircraft 10 comprises a fuselage 12, at least one wing 14 connected to the fuselage 12 and propulsion assemblies 16 connected to the wing 14 and arranged on either side of the fuselage 12. As illustrated in Figures 2 and 3, each propulsion assembly 16 comprises a propeller 18 which has an axis of rotation A18.

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

[0004] An electric propulsion assembly includes several electric motors 20 and a transmission system 22, such as a gearbox for example, configured to couple the electric motors 20 to the propeller 18.

[0005] As illustrated in [Fig.3], the transmission system 22 comprises a first housing 24 which has, in the longitudinal direction, a front wall F24 oriented towards the propeller 18 and a rear wall F24' on which the electric motors 20 are fixed, as well as at least one kinematic chain 26 positioned in the first housing 24 which has at least one input 28 for each electric motor 20 and an output 30, in the form of an output shaft, passing through the front wall F24 to be coupled to the propeller 18.

[0006] Each electric motor 20 has a second housing 32 which includes a support face F32, fixed against the rear wall F24' of the first housing 24, and an output shaft 34, projecting from the support face F32, passing through the rear wall F24' of the first housing 24. This output shaft 34 is coupled with 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 comprises a freewheel configured to occupy a coupled state in which the output shaft 34 of the corresponding electric motor 20 is coupled in rotation and transmits a rotational movement to the kinematic chain 26 of the transmission system 22 as well as a discoupled state, in case of an incident for example, in which 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 a rotational movement to it.

[0008] In this way, if an electric motor 20 is no longer working and its output shaft 34 is blocked from rotating, the coupling system 36 allows it to be isolated from the kinematic chain 26 which remains operational and transmits the rotational movements of the other electric motors 20 to the propeller 18.

[0009] The coupling systems 36 require more frequent maintenance operations than the other elements of the transmission system 22. For each of them, the transmission system 22 must be removed, which involves dismantling the electric motors 20, and its housing 24 must be opened in order to access the coupling systems 36. These different steps are relatively long, tedious and costly.

[0010] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0011] To this end, the invention relates to a propulsion assembly comprising a propulsion system, at least one electric motor and a transmission system coupled to the propulsion system, the transmission system comprising first and second transverse walls which delimit an interior zone located between the first and second transverse walls, a first exterior zone separated from the interior zone by the first transverse wall and a second exterior zone separated from the interior zone by the second transverse wall, the electric motor being connected to the first transverse wall and positioned in the first exterior zone, said electric motor having an output coupled by a coupling device to an input of the transmission system positioned in the interior zone.

[0012] According to the invention, the coupling device comprises: a. a first coupling shaft coupled to the output of the electric motor, passing through the transmission system and having a first end protruding into the second outer zone, b. a second coupling shaft coupled to the input of the transmission system, passing through at least the second transverse wall and having a first end projecting into the second outer zone, c. a coupling system configured to rotationally couple the first ends of the first and second coupling shafts, positioned in the second outer zone.

[0013] According to the invention, the coupling system is positioned outside the transmission system. Consequently, it is no longer necessary to remove and disassemble the transmission system to perform maintenance on the coupling system, thus increasing the time between two maintenance operations on the transmission system. Positioning the electric motor and its associated coupling system on either side of the transmission system results in a more compact assembly.

[0014] According to another feature, the second coupling shaft is hollow and configured to house the first coupling shaft.

[0015] According to another feature, the first and second coupling shafts are coaxial.

[0016] According to another feature, the coupling system is positioned inside the second coupling shaft.

[0017] According to another feature, the coupling device includes a plug configured to seal the first end of the second coupling shaft, connected by a removable link to the second coupling shaft.

[0018] According to a first embodiment, the electric motor includes an output shaft passing through the transmission system, the output shaft and the first coupling shaft of the coupling device forming only one and the same shaft.

[0019] According to a second embodiment, the electric motor includes an output shaft positioned in the first outer zone. 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 having a second end positioned in the first outer zone and coupled to the output shaft of the electric motor.

[0020] According to another feature, the second coupling shaft includes a second end that cooperates with the first transverse wall. In addition, the propulsion assembly includes a pivoting link comprising a first rotational guide interposed between a section of the second coupling shaft and the second transverse wall, and a second rotational guide interposed between the second end of the second coupling shaft and the first transverse wall.

[0021] According to another feature, the propulsion system is positioned in the second outer zone.

[0022] According to another feature, the coupling system is disengageable and configured to occupy a coupled state in which the output of the electric motor is rotationally coupled and transmits a rotational motion to the input of the transmission system, as well as a disengaged state in which the output of the electric motor is no longer coupled to the input of the transmission system and no longer transmits rotational motion to it.

[0023] According to another feature, the coupling system is configured to switch from the coupled state to the uncoupled state as soon as a torque transmitted via the coupling system exceeds a given threshold or is no longer within a given range.

[0024] According to another feature, the coupling system includes a free wheel configured to occupy a rotationally coupled state in which the first coupling shaft is rotationally coupled and transmits a rotational motion to the second coupling shaft, and an uncoupled state in which the first coupling shaft is no longer rotationally coupled to the second coupling shaft and no longer transmits a rotational motion to it.

[0025] The invention also relates to an aircraft comprising at least one propulsion assembly according to one of the preceding characteristics.

[0026] Other features and advantages will become apparent from the following description of the invention, given by way of example only, with reference to the accompanying drawings, among which:

[0027] [Fig-1] is a side view of an aircraft,

[0028] [Fig.2] is a schematic side view of an electric propulsion assembly illustrating a method of realizing earlier art,

[0029] [Fig.3] is a schematic cross-section of a transmission system and electric motors of a propulsion assembly illustrating an embodiment of the prior art,

[0030] [Fig.4] is a schematic cross-section of part of a propulsion assembly illustrating one embodiment,

[0031] [Fig.5] is a cross-section of part of a transmission system, an electric motor and a coupling system illustrating one embodiment of the invention.

[0032] According to an embodiment visible in [Fig.4], an electric propulsion assembly 40 comprises a propeller 42 which has an axis of rotation A42, several electric motors 44 and a transmission system 46, such as a gearbox for example, configured to couple the electric motors 44 to the propeller 42.

[0033] According to one application, an aircraft comprises at least one such propulsion assembly 40. Of course, the invention is not limited to this application. Regardless of the application, the electric propulsion assembly 40 comprises a propulsion system, such as a propeller for example, several electric motors 44, and a transmission system 46 configured to couple the electric motors 44 to the propulsion system.

[0034] According to a configuration visible in [Fig. 4], the transmission system 46 The invention comprises a first housing 48 which, in the longitudinal direction, has a front wall F48 oriented towards the propulsion system and a rear wall F48', to which the electric motors 44 are attached, as well as at least one drive train 50 positioned in the first housing 48 which has 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 to be coupled to the propulsion system. According to a configuration visible in [Fig. 4], the input 52 of the transmission system 46 is a pinion. Of course, the invention is not limited to this embodiment. Thus, the input 52 of the transmission system 46 could be a hollow shaft or any other element enabling coupling and the transmission of rotational motion.

[0035] Each electric motor 44 comprises a second housing 56 having a first face 56.1 oriented towards the transmission system 46 and a second face 56.2 opposite the first face 56.1 and the transmission system 46. The drive assembly 40 includes, for each electric motor 44, connecting elements 58 for attaching the electric motor 44 to the first housing 48 of the transmission system 46. By way of example, the connecting elements 58 are screws that pass through tabs attached to the second housing 56 of the electric motor 44, each screwing into a tapped hole attached to the first housing 48 of the transmission system 46. Of course, the invention is not limited to this embodiment for the connecting elements 58.

[0036] According to one arrangement, at least one electric motor 44 is positioned against the rear wall F48' of the first housing 48 of the transmission system 46 and connected to the rear wall F48' by the connecting elements 58.

[0037] According to another arrangement, at least one electric motor 44 is positioned against the front wall F48 of the first housing 48 of the transmission system 46 and connected to the front wall F48 by the connecting elements 58.

[0038] Regardless of the arrangement, the transmission system (more particularly its first housing 48) comprises a first transverse wall PT1 among the front and rear walls F48, F48' and a second transverse wall PT2, different from the first transverse wall PT1, among the front and rear walls F48, F48'. The first and second transverse walls PT1, PT2 delimit an inner zone ZI located between the first and second transverse walls PT1, 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, said electric motor 44 having an output 60 coupled to an input 52 of the transmission system 46 positioned in the inner zone ZI.

[0039] Each electric motor 44 includes an output 60, such as an output shaft 62 for example connected to the second housing 56 by a pivoting link 64, which has a pivot axis A62.

[0040] According to one arrangement, the pivot axis A62 of the output shaft 62 is substantially parallel to the longitudinal direction. The first and second faces 56.1, 56.2 are substantially perpendicular to the pivot axis A62 and offset from each other along the longitudinal direction.

[0041] According to a configuration visible on [Fig.4], the output shaft 62 extends from the first face 56.1, passes through the transmission system 46, in particular the front and rear walls F48, F48' of the first housing 48, and has a free end 62.1 projecting from the front wall F48, offset forward from said front wall F48.

[0042] According to another configuration visible in [Fig.5], the output shaft 62 is hollow and offset towards the rear relative to the first face 56.1 of the second housing 56 and the rear wall F48' of the first housing 48.

[0043] Of course, the output 60 of the electric motor 44 is not limited to these configurations. Thus, the output 60 of the electric motor 44 could be a pinion or any other element enabling coupling and the transmission of a rotational motion.

[0044] The propulsion assembly 40 includes at least one coupling device 66 connecting the output 60 of one of the electric motors 44 located in the first outer zone ZE1 and the input 52 of the transmission system 46, configured to transmit a rotational motion between the output 60 and the input 52.

[0045] This coupling device 66 comprises: a. a first coupling shaft 68 coupled to the output 60 of the electric motor 44, passing through the first housing 48 and having a first end 68.1 projecting into the second outer zone ZE2, b. a second coupling shaft 70 coupled to the input 52 of the transmission system 46, passing through at least the second transverse wall PT2 of the first housing 48 and having a first end 70.1 projecting into the second outer zone ZE2, c. a coupling system 72 configured to rotationally couple the first ends 68.1, 70.1 of the first and second coupling shafts 68 70, positioned in the second outer zone ZE2.

[0046] According to one configuration, the propulsion assembly 40 includes a coupling device 66 for each electric motor 44 whether it is positioned in the first external zone ZE1 or in the second external zone ZE2.

[0047] The coupling system 72 is disengageable and configured to occupy a state The coupling system 72 has a coupled state in which the output 60 of the electric motor 44 is rotationally coupled and transmits a rotational motion to the input 52 of the transmission system 46, and a discoupled state, for example in the event of an incident, 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 a rotational motion to it. The coupling system 72 switches from the coupled state to the discoupled state, for example in the event of an incident, as soon as a torque transmitted via the coupling system 72 exceeds a given threshold or is no longer within a given range.

[0048] In this way, if the electric motor 44 coupled to the coupling system 72 no longer works and its output shaft 62 is blocked in rotation for example, the coupling system 72 makes it possible to isolate it from the transmission system 46 which remains operational and transmits the rotational movements of the other electric motors to the propulsion system.

[0049] According to one embodiment, the coupling system 72 includes a free wheel 72.1 configured to occupy a rotationally coupled state in which the first coupling shaft 68 is rotationally coupled and transmits a rotational motion to the second coupling shaft 70, as well as a discoupled state, in case of an incident for example, in which the first coupling shaft 68 is no longer rotationally coupled to the second coupling shaft 70 and no longer transmits a rotational motion to it.

[0050] According to one configuration, the coupling system 72 comprises first and second rotational guides 72.2, 72.3 positioned on either side of the free wheel 72.1. The latter comprises a ring having an inner surface which cooperates with the first coupling shaft 68 and an outer surface which cooperates with the second coupling shaft 70, at least one of the surfaces among the inner and outer surfaces being coupled by friction with the first or second coupling shaft 68, 70.

[0051] Since the free wheel 72.1 is located outside the first housing 48 of the transmission system 46, any dust generated by the friction coupling of the free wheel 72.1 does not pollute the inside of the transmission system 46, thus limiting the risks of premature degradation of the components of the transmission system 46.

[0052] To obtain a more compact assembly, for at least one electric motor 44, the second coupling shaft 70 is hollow and configured to house the first coupling shaft 68. According to one arrangement, the first and second coupling shafts 68, 70 are coaxial.

[0053] According to one arrangement, the coupling system 72 is positioned inside the second coupling shaft 70, between the first ends 68.1, 70.1 of the first and second coupling shafts 68, 70, which allows it to be protected.

[0054] In addition, the coupling device 66 includes a plug 74 configured to seal the first end 70.1 of the second coupling shaft 70, connected by a detachable link to the second coupling shaft 70. This embodiment makes it possible to strengthen the protection of the coupling system 72.

[0055] According to a first embodiment shown in [Fig. 4], the output shaft 62 of the electric motor 44 and the first coupling shaft 68 of the coupling device 66 form a single shaft. This shaft can be hollow or solid.

[0056] According to a second embodiment shown in [Fig. 5], 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. In this embodiment, the first coupling shaft 68 comprises a second end 68.2 positioned in the first outer zone ZE1 and coupled to the output shaft 62 of the electric motor 44. In 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. For example, the second end 68.2 and the output shaft 62 are splined. Other solutions are conceivable for coupling the output shaft 62 of the electric motor 44 and the first coupling shaft 68 of the coupling device 66.

[0057] According to one embodiment, the coupling device 66 includes a pinion 76 integral with the second coupling shaft 70 and fixed relative to the latter, which cooperates with a pinion or ring of the input 52 of the transmission system 46.

[0058] According to one arrangement, the propulsion assembly 40 comprises a pivot joint 78 connecting the second coupling shaft 70 and the first housing 48 of the transmission system 46. According to one embodiment, the second coupling shaft 70 comprises a second end 70.2 which cooperates with the first transverse wall PT1. In addition, the pivot joint 78 comprises a first rotational guide 78.1, such as a bearing, interposed between a section 70.3 of the second coupling shaft 70 and the second transverse wall PT2, and a second rotational guide 78.2, such as a bearing, interposed between the second end 70.2 of the second coupling shaft 70 and the first transverse wall PT1.

[0059] According to a first configuration, the electric motors 44 are all positioned against the rear wall F48' of the transmission system 46 and the coupling system 72 of each of them is positioned in front of the front wall F48 of the transmission system 46, in the second outer zone ZE2 in which the propulsion system is positioned.

[0060] 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 it is positioned at the rear of the rear wall F48'.

[0061] Regardless of the embodiment, the coupling system 72 is positioned outside the first housing 48 of the transmission system 46. Consequently, it is no longer necessary to remove and disassemble the transmission system 46 to perform maintenance on the coupling system 72, thus increasing the time between maintenance operations on the transmission system 46. Positioning the electric motor 44 and its associated coupling system 72 on either side of the transmission system 46 results in a more compact assembly. Furthermore, when the coupling system 72 is positioned at the front of the transmission system, it is more accessible, which facilitates maintenance operations.

Claims

Claims

1. A propulsion assembly comprising a propulsion system, at least one electric motor (44) and a transmission system (46) coupled to the propulsion system, the transmission system (46) comprising first and second transverse walls (PT1) which delimit an inner zone (ZI) located between the first and second transverse walls (PT1, 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 positioned in the first outer zone (ZE1), said electric motor (44) having an output (60) coupled by a coupling device (66) to an input (52) of the transmission system (46) positioned in the inner zone (ZI);characterized in that the coupling device (66) comprises: a. a first coupling shaft (68) coupled to the output (60) of the electric motor (44), passing through the transmission system (46) and having a first end (68.1) projecting into the second outer zone (ZE2), b. a second coupling shaft (70) coupled to the input (52) of the transmission system (46), passing through at least the second transverse wall (PT2) and having a first end (70.1) projecting into the second outer zone (ZE2), c. a coupling system (72) configured to rotationally couple the first ends (68.1, 70.1) of the first and second coupling shafts (68 70), positioned in the second outer zone (ZE2).;

2. Propulsion assembly according to the preceding claim, characterized in that the second coupling shaft (70) is hollow and configured to house the first coupling shaft (68).

3. Propulsion assembly according to the preceding claim, characterized in that the first and second coupling shafts (68, 70) are coaxial.

4. Propulsion assembly according to one of claims 2 to 3, characterized in that the coupling system (72) is positioned inside the second coupling shaft (70).

5. Propulsion assembly according to the preceding claim, characterized in that the coupling device (66) comprises a plug (74) configured to close the first end (70.1) of the second coupling shaft (70), connected by a removable connection to the second coupling shaft (70).

6. Propulsion assembly according to one of the preceding claims, characterized in that the electric motor (44) comprises an output shaft (62) passing through the transmission system (46) and in that the output shaft (62) and the first coupling shaft (68) of the coupling device (66) form a single shaft.

7. Propulsion assembly according to one of claims 1 to 5, characterized in that the electric motor (44) comprises an output shaft (62) positioned in the first outer zone (ZE1) and in that 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) positioned in the first outer zone (ZE1) and coupled to the output shaft (62) of the electric motor (44).

8. Propulsion assembly according to one of the preceding claims, characterized in that the second coupling shaft (70) comprises a second end (70.2) which cooperates with the first transverse wall (PT1) and in that the propulsion assembly (40) comprises a pivoting connection (78) comprising a first rotational guide (78.1) interposed between a section (70.3) of the second coupling shaft (70) and the second transverse wall (PT2) as well as a second rotational guide (78.2) interposed between the second end (70.2) of the second coupling shaft (70) and the first transverse wall (PT1).

9. Propulsion assembly according to one of the preceding claims, characterized in that the propulsion system is positioned in the second outer zone (ZE2).

10. A propulsion assembly according to one of the preceding claims, characterized in that the coupling system (72) is disengageable and configured to occupy a coupled state in which the output (60) of the electric motor (44) is rotationally coupled and transmits a rotational movement at the input (52) of the transmission system (46) as well as 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 rotational movement to it.

11. Propulsion assembly according to the preceding claim, characterized in that the coupling system (72) is configured to switch from the coupled state to the uncoupled state as soon as a torque transmitted via the coupling system (72) exceeds a given threshold or is no longer within a given range.

12. Propulsion assembly according to one of the preceding claims, characterized in that the coupling system (72) comprises a freewheel (72.1) configured to occupy a rotationally coupled state in which the first coupling shaft (68) is rotationally coupled and transmits a rotational movement to the second coupling shaft (70) as well as an uncoupled state in which the first coupling shaft (68) is no longer rotationally coupled to the second coupling shaft (70) and no longer transmits a rotational movement thereto.

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

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