Aircraft propulsion system comprising at least one disengageable coupling device linking an electric motor and a transmission system

Abstract

Aircraft propulsion assembly comprising at least one disengageable coupling device connecting an electric motor and a transmission system. The invention relates to a disengageable coupling device, adapted to connect an electric motor (32) and a transmission system (34) of an aircraft propulsion assembly, comprising: a first shaft (36) which includes first and second sections (36.1, 36.2), the second section (36.2) comprising a coupling section (40), a second shaft (38) having a housing (42) configured to house the coupling section (40), at least one freewheel (44) interposed between the coupling section (40) of the first shaft (36) and the second shaft (38), allowing the shaft (36, 38) connected to the electric motor (32) to drive the shaft (36, 38) connected to the transmission system (34) in rotation only in a first direction of rotation, a disengageable system (48) configured to occupy a coupled state as well as a disengaged state in which the first and second sections (36.1, 36.2) are separated when the second section (36.2) or the second shaft (38) rotates in the first direction of rotation relative to the stationary first section (36.1). Figure 4.

Description

Title of the invention: Aircraft propulsion assembly comprising at least one disengageable coupling device connecting an electric motor and a transmission system

[0001] The present application relates to an aircraft propulsion assembly comprising at least one disengageable coupling device linking an electric motor and a transmission system.

[0002] According to an embodiment visible in [Fig.1], a propulsion assembly 10 of an aircraft comprises a propeller 12, several electric motors 14, a transmission system 16 such as a gearbox for example, a first coupling device connecting the transmission system 16 and the propeller 12 and, for each electric motor 14, a second coupling device 18 connecting each electric motor 14 and the transmission system 16.

[0003] According to a configuration visible on [Fig.2], each second coupling device 18 comprises a hollow input shaft 20 integral with the transmission system 16, an output shaft 22 integral with the electric motor 14 and positioned coaxially in the hollow input shaft 20, a free wheel 24 positioned between the input and output shafts 20, 22 and first and second rotation guides 26.1, 26.2 positioned between the input and output shafts 20, 22 on either side of the free wheel 24.

[0004] The freewheel 24 is configured so that the output shaft 22 connected to the electric motor 14 drives the input shaft 20 connected to the transmission system 16 in rotation when the output shaft 22 rotates in a first direction of rotation and at a speed greater than or equal to that of the input shaft 20 and so that the input shaft 20 connected to the transmission system 16 does not drive the output shaft 22 connected to the electric motor 14 in rotation when the input shaft 20 rotates in the first direction of rotation and at a speed greater than that of the output shaft 22.

[0005] Thanks to this free wheel 24, the output shaft 22 of an electric motor 14 is not driven in rotation by the transmission system 16 when it is not rotating, for example due to a malfunction.

[0006] In the event of damage to the free wheel 24, for example when it is seized, it no longer performs this protective function and the electric motor 14 can be driven in rotation by the transmission system 16.

[0007] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0008] To this end, the invention relates to a disengageable coupling device adapted to connect an electric motor and a transmission system of an aircraft propulsion assembly, said disengageable coupling device comprising: a. a first shaft configured to be connected to a first element among the electric motor and the transmission system, said first shaft having a coupling section, b. a second shaft configured to be connected to a second element, different from the first element, of the electric motor and the transmission system, said second shaft having a housing configured to house the coupling section of the first shaft, c. at least one freewheel, interposed between the coupling section of the first shaft and the second shaft, allowing the first or second shaft connected to the electric motor to drive the first or second shaft connected to the transmission system in rotation in a first direction of rotation only.

[0009] According to the invention, the first shaft comprises first and second sections, the first section having an end oriented towards the second section and being connected to the first element among the electric motor and the transmission system, the second section having an end oriented towards the first section and comprising the coupling section.In addition, the disengageable coupling device includes a disengageable system, configured to occupy a coupled state in which the first and second sections are kinematically linked and an uncoupled state in which the first and second sections are separated, and a control member having a helical linkage which connects the first section and the second section or the second shaft and has a thread pitch such that, when the second section or the second shaft rotates in the first direction of rotation relative to the first section, the helical linkage causes the disengageable system to switch from the coupled state to the uncoupled state.

[0010] Thus, in the event of a malfunction of the freewheel, the shaft connected to the transmission system does not drive in rotation, thanks to the disengageable system, the shaft connected to the electric motor, which reduces the risk of a short circuit occurring in the electric motor.

[0011] According to another feature, the control member comprises a threaded portion located at a first end among the ends of the first and second sections and a tapped housing located at a second end different from the first end among the ends of the first and second sections, said tapped housing being configured to house the threaded portion and cooperate with the latter so as to form the helical link.

[0012] According to another feature, the first section is configured to be connected to the electric motor.

[0013] According to another feature, the threaded portion is provided at the end of the first section, the tapped housing being provided at the end of the second section.

[0014] According to another feature, the control member comprises a threaded portion positioned on the first section and oriented towards the second shaft and a tapped portion, positioned on the second shaft and oriented towards the first section, configured to cooperate with the threaded portion so as to form the helical link.

[0015] According to another feature, the first segment is configured to be connected to the transmission system.

[0016] According to another feature, the first and second sections comprise first and second end faces, respectively. In addition, the disengageable system comprises shapes, located at the end faces of the first and second sections, configured to cooperate with each other such that, when the end faces of the first and second sections are pressed against each other, the first and second sections are kinematically linked in at least the first direction of rotation.

[0017] According to another feature, the disengageable coupling device includes at least one rotational guide interposed between the second shaft and the first section.

[0018] According to another feature, the rotational guide is positioned between the threaded cylindrical portion and the terminal face of the first section.

[0019] The invention also relates to an aircraft propulsion assembly comprising at least one disengageable coupling device according to one of the preceding characteristics, as well as an aircraft comprising at least one such propulsion assembly.

[0020] 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:

[0021] [Fig. 1] is a perspective view of a propulsion assembly illustrating an embodiment of the prior art,

[0022] [Fig.2] is a longitudinal section of a coupling device connecting an electric motor and a transmission system illustrating an embodiment according to the prior art,

[0023] [Fig.3] is a longitudinal section of a disengageable coupling device connecting an electric motor and a transmission system illustrating an embodiment according to the invention,

[0024] [Fig.4] is a longitudinal section of a disengageable coupling device linking an electric motor and a transmission system illustrating another embodiment according to the invention.

[0025] According to one embodiment, a disengageable coupling device 30 is configured to connect an electric motor 32 and a transmission system 34 of an aircraft propulsion system. Thus, an aircraft comprises at least one propulsion system that incorporates at least one such disengageable coupling device 30.

[0026] This disengageable coupling device 30 comprises a first shaft 36 directly or indirectly connected to a first element among the electric motor 32 and the transmission system 34 and a second hollow shaft 38 directly or indirectly connected to a second element, different from the first element, among the electric motor 32 and the transmission system 34.

[0027] According to an embodiment visible in [Fig.3], the first shaft 36 is connected to the electric motor 32 and the second shaft 38 is connected to the transmission system 34.

[0028] According to another embodiment visible in [Fig.4], the first shaft 36 is connected to the transmission system 34 and the second shaft 38 is connected to the electric motor.

[0029] The first and second trees 36, 38 respectively have first and second axes of revolution A36, A38 coaxial.

[0030] The first shaft 36 has a coupling section 40, positioned in the second shaft 38, which has a first peripheral surface S40 that is substantially cylindrical and oriented towards the hollow second shaft 38. In addition, the hollow second shaft 38 has a housing 42, configured to house the coupling section 40, which has a second peripheral surface S42 that is substantially cylindrical, coaxial with the first peripheral surface S40 and oriented towards the coupling section 40 of the first shaft 36.

[0031] The disengageable coupling device 30 includes at least one free wheel 44 interposed between the coupling section 40 of the first shaft 36 and the second shaft 38 and positioned in the housing 42. The free wheel 44 has first and second coaxial surfaces in contact respectively with the first and second peripheral surfaces S40, S42.

[0032] This freewheel 44 is configured so that the shaft connected to the electric motor 32, one of the first and second shafts 36, 38, drives the shaft connected to the transmission system 34, one of the first and second shafts 36, 38, in rotation when the shaft connected to the electric motor 32 rotates in a first direction of rotation and at a speed greater than or equal to that of the shaft connected to the transmission system 34, and so that the shaft connected to the transmission system 34 does not drive the shaft connected to the electric motor 32 in rotation when the shaft connected to the transmission system 34 rotates in the first direction of rotation and at a speed greater than that of the shaft connected to the electric motor 32. Thus, this freewheel 44 allows the shaft connected to the electric motor 32 to drive the shaft connected to the transmission system 34 in a first direction of rotation only.

[0033] This free wheel 44 is not further detailed as it may be identical to that of the prior art.

[0034] According to one embodiment, the disengageable coupling device 30 comprises at least one rotary guide 46 interposed between the coupling section 40 of the first shaft 36 and the second shaft 38. Each rotary guide 46 has first and second coaxial surfaces in contact respectively with the first and second peripheral surfaces S40, S42. According to one configuration, the disengageable coupling device 30 comprises first and second rotary guides 46, 46' positioned on either side of the freewheel 44.

[0035] For the sake of indication, each rotational guide 46, 46' is a bearing or a support.

[0036] Each rotational guide 46, 46' is not further detailed as it may be identical to that of the earlier art.

[0037] The first shaft 36 comprises first and second sections 36.1, 36.2, the first section 36.1 being directly or indirectly connected to a first element of the electric motor 32 and the transmission system 34, the second section 36.2 comprising the coupling section 40 connected to the second shaft 38 by the freewheel 44. The first and second sections 36.1, 36.2 have aligned axes of revolution A36.1, A36.2. The first section 36.1 has an end and a terminal face S361 oriented towards the second section 36.2. The second section 36.2 has an end and a terminal face S36.2 oriented towards the first section 36.1.

[0038] The disengageable coupling device 30 includes a disengageable system 48 configured to occupy a coupled state in which the first and second sections 36.1, 36.2 are kinematically linked and an uncoupled state in which the first and second sections 36.1, 36.2 are separated and not kinematically linked.

[0039] The disengageable coupling device 30 also includes a control member 50 configured to control the coupled / disengaged state of the disengageable system 48. This control member 50 is a passive member. It comprises a helical linkage 52, connecting the first section 36.1 and the second section 36.2 or the second shaft 38, which has a thread pitch such that when the second section 36.2 or the second shaft 38 rotates in the first direction relative to the first section 36.1, the helical linkage 52 causes the first and second sections 36.1, 36.2 to separate and the disengageable system 48 to transition from the coupled state to the disengaged state.

[0040] The control element 50 is configured to switch the disengageable system 48 from its coupled state to its disengaged state following a rotational movement in the first direction (called positive rotational movement) with negative torque or following a rotational movement in the opposite direction to the first direction (called negative torque movement). negative rotation) with positive torque. The control element 50 is configured to move the disengageable system 48 from its disengaged state to its coupled state following a rotational movement in the first direction with positive torque or following a rotational movement in the opposite direction to the first direction with negative torque.

[0041] According to the embodiment shown in [Fig. 3], the disengageable system 48 and the control member 50 are combined and comprise a threaded portion 54 located at a first end among the ends of the first and second sections 36.1, 36.2 and a threaded housing 56, located at a second end different from the first end among the ends of the first and second sections 36.1, 36.2, configured to house the threaded portion 54 and cooperate with it so as to form the helical connection 52. According to this embodiment, the coupled state is obtained when the end faces S36.1, S36.2 of the first and second sections 36.1, 36.2 are in contact with each other.

[0042] According to one configuration, the threaded portion 54 is provided at the end of the first section 36.1 and the tapped housing 56 is provided at the end of the second section 36.2.

[0043] According to the embodiment shown in [Fig.4], the disengageable system 48 and the control member 50 are separate.

[0044] The control member 50 includes a threaded portion 58 positioned on the first section 36.1 and oriented towards the second hollow shaft 38 and a tapped portion 60, positioned on the second shaft 38 and oriented towards the first section 36.1, configured to cooperate with the threaded portion 58 so as to form the helical link 52.

[0045] According to the embodiment visible in [Fig.4], the disengageable system 48 comprises forms, located at the terminal faces S36.1, S36.2 of the first and second sections 36.1, 36.2, configured to cooperate so that when the terminal faces S36.1, S36.2 of the first and second sections 36.1, 36.2 are pressed against each other, the first and second sections 36.1, 36.2 are kinematically linked in the first direction of rotation at least.

[0046] In one configuration, the disengageable coupling device 30 comprises at least one rotary guide 62 interposed between the second hollow shaft 38 and the first section 36.1. Each rotary guide 62 has first and second coaxial surfaces in contact with the second hollow shaft 38 and the first section 36.1, respectively. By way of example, each rotary guide 62 is a bearing or a bushing. In one arrangement, the rotary guide 62 is positioned between the threaded cylindrical portion 58 and the first end face S36.1.

[0047] According to a first architecture, for each electric motor 32, the disengageable coupling device 30 is positioned between the electric motor 32 and the transmission system 34.

[0048] According to a second architecture, the electric motors 32 are positioned on the rear face of the transmission system 34 and the disengageable coupling devices 18 are positioned on the front face of the transmission system 34 oriented towards the propeller. In addition, the propulsion assembly includes, for each electric motor, a coupling shaft, connecting the output of the electric motor and its associated disengageable coupling device, which passes through the transmission system.

[0049] The operating principle of the disengageable coupling device visible in [Fig.3] is now described.

[0050] In operation, when the electric motor 32 drives the first shaft 36 in the first direction of rotation SI, the latter drives via the free wheel 44 the second shaft 38 connected to the transmission system 34.

[0051] When the freewheel 44 is functioning correctly, if the electric motor 32 is stopped and if the transmission system 34 drives the second shaft 38 in rotation in the first direction of rotation SI', the freewheel 44 does not transmit this rotational movement to the first shaft 36 connected to the electric motor 32.

[0052] When the freewheel 44 is not functioning correctly, if the electric motor 32 is stopped and the transmission system 34 drives the second shaft 38 in rotation in the first direction of rotation SI', the freewheel 44 is not functioning correctly, and the second shaft 38 drives the second section 36.2 in rotation in the first direction of rotation SI'. Since the first section 36.1 is stationary, the rotation of the second section 36.2 in the first direction of rotation SI' causes, via the helical linkage 52, the first and second sections 36.1 and 36.2 to separate and transition from the coupled to the uncoupled state. Consequently, even if the second section 36.2 rotates, this movement is not transmitted to the first section 36.1 connected to the electric motor 32.

[0053] The operating principle of the disengageable coupling device visible in [Fig.4] is now described.

[0054] In operation, when the electric motor 32 drives the second shaft 38 in the first direction of rotation SI, the latter drives via the free wheel 44 the first shaft 36 connected to the transmission system 34.

[0055] When the freewheel 44 is functioning correctly, if the electric motor 32 is stopped and if the transmission system 34 drives the first shaft 36 in rotation in the first direction of rotation SI', the freewheel 44 does not transmit this rotational movement to the second shaft 38 connected to the electric motor 32.

[0056] When the freewheel 44 does not function correctly, if the electric motor 32 is stopped, the second shaft 38 and the second section of the first shaft 36 are stationary relative to each other. If the transmission system 34 drives the first section 36.1 of the first shaft 36 in rotation in the first direction SI', the second section 36.2 being stationary, the rotation of the first section 36.1 in the first direction SI' causes, via the helical linkage 52, a separation of the first and second sections 36.1 and 36.2 and a transition from the coupled to the uncoupled state. Consequently, even if the first section 36.1 rotates, this movement is not transmitted to the second shaft 38 connected to the electric motor 32.

[0057] In the first and second embodiments, in the event of a malfunction of the free wheel 44, the shaft connected to the transmission system 34 does not drive in rotation, thanks to the disengageable system 48, the shaft connected to the electric motor 32, which reduces the risk of a short circuit occurring in the electric motor 32 and prevents any type of electrical regeneration of the electric motor 32 by preventing it from performing a rotational movement.

Claims

Demands

1. A disengageable coupling device adapted for connecting an electric motor (32) and a transmission system (34) of an aircraft propulsion assembly, said disengageable coupling device comprising: a. a first shaft (36) configured to be connected to a first element among the electric motor (32) and the transmission system (34), said first shaft (36) having a coupling section (40), b. a second shaft (38) configured to be connected to a second element, different from the first element, of the electric motor (32) and the transmission system (34), said second shaft (38) having a housing (42) configured to house the coupling section (40) of the first shaft (36), c. at least one freewheel (44), interposed between the coupling section (40) of the first shaft (36) and the second shaft (38), allowing the first or second shaft (36, 38) connected to the electric motor (32) to drive the first or second shaft (36, 38) connected to the transmission system (34) in rotation only in a first direction of rotation, characterized in that the first shaft (36) comprises first and second sections (36.1, 36.2), the first section (36.1) having an end oriented towards the second section (36.2) and being connected to the first element of the electric motor (32) and the transmission system (34), the second section (36.2) having an end oriented towards the first section (36.1) and comprising the coupling section (40), and in that the disengageable coupling device comprises a disengageable system (48) configured to occupy a coupled state in which the first and second sections (36.1, 36.2) are kinematically linked, as well as a disengaged state in which the first and second sections (36.1, 36.2) are separated, and a control member (50) comprising a helical linkage (52) that connects the first section (36.1) and the second section (36.2) or the second shaft (38) and has a screw pitch such that, when the second section (36.2) or the second shaft (38) rotates in the first direction of rotation relative to the first section (36.1), the helical link (52) causes the disengageable system (48) to pass from the coupled state to the disengaged state.

2. A disengageable coupling device according to claim 1, characterized in that the control member (50) comprises a threaded portion (54) located at a first end among the ends of the first and second sections (36.1, 36.2) and a threaded housing (56) located at a second end different from the first end among the ends of the first and second sections (36.1, 36.2), said threaded housing (56) being configured to house the threaded portion (54) and cooperate with the latter so as to form the helical link (52).

3. Disengageable coupling device according to claim 2, characterized in that the first section (36.1) is configured to be connected to the electric motor (32).

4. Disengageable coupling device according to any one of claims 2 to 3, characterized in that the threaded portion (54) is provided at the end of the first section (36.1), the tapped housing (56) being provided at the end of the second section (36.2).

5. Disengageable coupling device according to claim 1, characterized in that the control member (50) comprises a threaded portion (58) positioned on the first section (36.1) and oriented towards the second shaft (38) and a tapped portion (60), positioned on the second shaft (38) and oriented towards the first section (36.1), configured to cooperate with the threaded portion (58) so as to form the helical link (52).

6. Disengageable coupling device according to the preceding claim, characterized in that the first section (36.1) is configured to be connected to the transmission system (34).

7. A disengageable coupling device according to any one of claims 5 to 6, characterized in that the first and second sections (36.1, 36.2) comprise first and second end faces (S36.1, S36.2) respectively, and in that the disengageable system (48) comprises shapes, located at the end faces (S36.1, S36.2) of the first and second sections (36.1, 36.2), configured to cooperate with each other such that, when the end faces (S36.1, S36.2) of the first and second sections (36.1, 36.2) are pressed against each other, the first and second sections (36.1, 36.2) are kinematically linked in the first direction of rotation at least.

8. Disengageable coupling device according to any one of claims 5 to 7, characterized in that the disengageable coupling device comprises at least one rotational guide (62) interposed between the second shaft (38) and the first section (36.1).

9. Disengageable coupling device according to claims 7 and 8, characterized in that the rotational guide (62) is positioned between the threaded cylindrical portion (58) and the terminal face (S36.1) of the first section (36.1).

10. Aircraft propulsion assembly comprising at least one disengageable coupling device according to one of the preceding claims.

11. Aircraft comprising at least one propulsion system according to the preceding claim.

Images