System having a mechanical linkage device with two paths for mechanical torque transmission

Abstract

The present invention relates to a system comprising a linkage device (20) having a first shaft (25) and a second shaft (30), the linkage device (20) comprising a freewheel (35) interposed between the first shaft (25) and the second shaft (30) capable of transmitting only motor torque from the first shaft (25) to the second shaft (30) in motor mode. The linkage device (20) comprises a coupler (40), the coupler (40) being provided with a fusible section (45), the linkage device (20) comprising a dog clutch (50) capable of transmitting only motor torque from the coupler (40) to the first shaft (25) in electric generator mode. (Shorthand figure: Figure 1)

Description

Title of the invention: System having a mechanical linkage device with two paths for mechanical torque transmission

[0001] The present invention relates to a system having a two-way mechanical linkage device for transmitting mechanical torque. For example, a vehicle may be equipped with a mechanical device connected to a hybrid powertrain, this hybrid powertrain having at least one electric machine connected to the mechanical device by such a mechanical linkage device.

[0002] In particular, the mechanical device may include at least one rotor driven by a power transmission to contribute to the lift and / or propulsion of the aircraft. By way of illustration, the aircraft may include a power transmission driving at least one main rotor to provide at least partial lift or even propulsion, or even a rotor contributing to yaw control.

[0003] A hybrid thermal / electric drive system can be connected to the mechanical device to set it in motion, and in particular can be connected to the power transmission box according to the aforementioned example.

[0004] This hybrid powertrain comprises at least one internal combustion engine. The term "internal combustion engine" refers to turboshaft engines or any internal combustion engine, particularly piston engines, that can be used in such a powertrain. The term "internal combustion engine" is distinct from the term "electric motor," which refers to motors that consume only electrical energy.

[0005] Furthermore, the hybrid drive system includes at least one electric machine. Such an electric machine can operate in an electric motor mode by converting electrical energy into mechanical energy to contribute to the movement of the power transmission, but also in an electric generator mode by converting extracted mechanical energy into electrical energy that can be transmitted to an aircraft electrical network.

[0006] Document FR 3106570 describes a rotary-wing aircraft comprising at least one internal combustion engine and one backup electric motor.

[0007] Furthermore, the electric machine can be controlled, depending on the flight phase, to operate either in electric motor mode or in electric generator mode. The mechanical power transmitted to the mechanical device in electric motor mode may differ from the mechanical power that can be extracted during operation in electric generator mode.

[0008] Furthermore, the electrical machine may be subject to a risk of internal blockage. To resolve this problem, the electrical machine can be connected to the mechanical device by means of a mechanical linkage capable of disengaging the mechanical device from the electrical machine. This mechanical linkage can, for example, kinematically disengage the electrical machine from the mechanical device in the event of a blockage.

[0009] Document EP 3693627 B1 does not fall within the technical field of the invention and does not provide a solution to the aforementioned problem. Indeed, document EP 3693627 B1 relates to a selectable clutch device positioned between a primary drive system and a secondary drive system, the primary drive system having power transmission gearboxes and a primary engine, such as a turboshaft engine. The secondary drive system has a secondary engine, such as a turboshaft engine. The selectable clutch device comprises an input pinion fixed to an outer ring. A freewheel is interposed between the outer ring and an inner ring that is rotationally fixed to an output pinion. The selectable clutch device includes a bypass assembly for rotationally locking the outer ring and the inner ring in a coupled mode, and for rotationally locking the outer ring and the inner ring in an uncoupled mode.The bypass assembly includes a component with splines engaging with splines on the inner ring. The bypass assembly also includes an actuator for engaging, on demand, splines on this component with splines on the outer ring. In decoupled mode, the selectable clutch operates in a unidirectional torque transfer mode from the input gear to the output gear. In coupled mode, the selectable clutch operates in a bidirectional torque transfer mode between the input gear and the output gear via the bypass assembly.

[0010] Document FR3122407 discloses a transmission system for, on the one hand, transmitting a motor torque from a primary shaft of an electric machine operating in motor mode to a secondary shaft, and, alternatively, on the other hand, transmitting another motor torque from the secondary shaft to the primary shaft of the electric machine operating in generator mode. This system comprises two freewheels arranged in opposite phase.

[0011] The present invention then aims to provide a connection device innovative mechanics aimed at limiting the risks of the mechanical device jamming in the event of the electrical machine jamming and at limiting the risks of fire in the event of a short circuit in the electrical machine.

[0012] The invention thus relates to a transmission system equipped with a mechanical device connected to a drive installation, said drive installation comprising a machine electric capable of operating in a motor mode to move the mechanical device and in an electric generator mode by being moved by the mechanical device, the electric machine being kinematically connected to the mechanical device by a bidirectional linkage device, the linkage device comprising a first shaft kinematically connected to the electric machine and a second shaft kinematically connected to the mechanical device, the second shaft being movable in rotation about an axis of rotation in a direction of rotation, the linkage device comprising a free wheel interposed between the first shaft and the second shaft to only transmit a motor torque from the first shaft to the second shaft in motor mode.

[0013] This bidirectional linkage device includes a coupler, the coupler being provided with a fusible section, the coupler being fixed to the second shaft rotating around said axis of rotation, the linkage device including a dog clutch link being able to transmit only a motor torque from the coupler to the first shaft in electric generator mode.

[0014] The motor torque transmitted by the dog clutch link during the electric generator mode can be described as generator torque to distinguish it from the motor torque transmitted by the freewheel during the motor mode.

[0015] The dog clutch link and the freewheel can thus make it possible to obtain two different transmission paths of a mechanical torque during two different modes of operation.

[0016] During motor operation, the first shaft is set in motion by the electric machine. The linkage transmits a motor torque from the first shaft to the second shaft via the freewheel due to the design of the dog clutch. The dog clutch is inoperative in this case. Consequently, a blockage of the electric machine does not cause a blockage of the mechanical device because of the freewheel and the fusible link. If the electric machine blocks, the freewheel becomes unsynchronized and causes a change in the transmission of forces to activate the fusible link. If no action is taken, the fusible link will eventually rupture and disconnect the electric machine from the mechanical device.

[0017] During electric generator mode, the second shaft is driven by the mechanical device. The linkage transmits a motor torque from the second shaft to the first shaft via the dog clutch. The freewheel is then desynchronized. In the event of a blockage of the electric machine, the fusible section can rupture in order to prevent hindering the operation of the mechanical device.

[0018] This separation of the transmission paths of a mechanical torque allows the fuse section to be arranged within the coupler. Indeed, the separation of the transmission paths of a mechanical torque allows for precise and easy dimensioning. The fuse section, in particular, is important when the power transmitted by the coupling device during generator mode is less than the power transmitted through the coupling device during motor mode. For example, the coupling device can transmit a mechanical power of approximately 250 to 300 kilowatts during motor mode, and approximately 30 to 50 kilowatts during generator mode.

[0019] Such a linking device can also be compact, and / or relatively light, and / or can be arranged relatively easily within an existing architecture.

[0020] The transmission system may include, for example, one or more of the following features, taken alone or in combination.

[0021] Thus, the coupler can include an intermediate shaft equipped with said fusible section and integral with the second shaft rotating around the axis of rotation, said intermediate shaft being connected to the first shaft by the dog clutch connection; the dog clutch connection having at least a non-zero play in rotation around the axis of rotation in the direction of rotation.

[0022] This game makes it possible to prevent the intermediate shaft from being driven by the first shaft during motor mode, in order to separate the power transmission paths in the linkage device.

[0023] According to a possibility compatible with the preceding ones, the dog clutch connection may include several first teeth which are fixed to the first shaft rotating around the axis of rotation and several second teeth which are fixed to the intermediate shaft rotating around the axis of rotation, each second tooth being arranged on an arc of a circle centered on the axis of rotation between an upstream first tooth and a downstream first tooth and being separated from the upstream first tooth by said clearance, the upstream first tooth being upstream of the downstream second tooth with regard to an observer during a rotation in the direction of rotation around the axis of rotation of the first shaft.

[0024] For example, such a game can be defined angularly by an angle between 45° and 60°.

[0025] The coupler is thus simple and compact.

[0026] According to a possibility compatible with the preceding ones, said intermediate shaft may include first splines engaging second splines of the second shaft.

[0027] According to a possibility compatible with the preceding ones, the linkage device may include an elastic return system interposed between the intermediate shaft and the second shaft, the elastic return system pushing the coupler into a predetermined coupling position allowing the dog clutch linkage to transmit a motor torque only from the coupler to the first shaft.

[0028] For example, the recall system tends to bring certain first teeth and second teeth into contact.

[0029] According to a possibility compatible with the preceding ones, said linkage device may include an actuator configured to move the coupler in translation from a predetermined coupling position allowing the dog clutch linkage to transmit a motor torque from the coupler to the first shaft at a predetermined decoupling position inhibiting the dog clutch linkage.

[0030] Such an actuator can be hydraulic, pneumatic, or even electric, for example. Such an actuator can, for instance, take the form of a cylinder. The actuator prevents the transmission of motor torque from the second shaft to the first shaft for safety reasons, particularly in the event of a short circuit in the electric machine during generator mode. Such an actuator can also be used to verify the operation of the connecting device during a pre-use test.

[0031] The actuator can be controlled by a controller, for example to move the coupler to the decoupling position in the event of a blockage or short circuit of the electrical machine. For this purpose, the system may include at least one sensor for detecting such an event, such as a current sensor and / or a rotational speed sensor, for example.

[0032] According to a possibility compatible with the preceding ones, the drive installation may include at least one heat engine kinematically connected to the mechanical device.

[0033] The invention also relates to an aircraft comprising such a transmission system.

[0034] For example, the mechanical device includes a transmission box of power, the power transmission box setting in motion at least one lift and / or propulsion rotor.

[0035] The invention and its advantages will become apparent in more detail in the following description, with illustrative examples given by reference to the accompanying figures, which represent:

[0036] [Fig. 1], a diagram showing a linking device according to the invention equipped with an actuator,

[0037] [Fig.2], a three-dimensional view showing the dog clutch connection of [Fig.1],

[0038] the [Fig.3], a diagram showing a linking device according to the invention arranged by for example within a transmission system, for example located within an aircraft,

[0039] [Fig. 4], a diagram showing a linking device according to the invention equipped with an actuator in a coupling position, and

[0040] [Fig. 5], a diagram showing a connecting device according to the invention equipped with a actuator in a decoupling position.

[0041] Elements present in several separate figures are assigned one and the same reference.

[0042] Figure 1 shows a bidirectional linkage device 20. This linkage device 20 comprises a first shaft 25 and a second shaft 30 that rotate about the same axis of rotation AXROT. The term "shaft" refers to a mechanical component that transmits power in the form of torque and rotational motion, this component being able to comprise one or more components.

[0043] The linking device 20 can be arranged within any system requiring bidirectional power transmission between two sets.

[0044] According to the example, the first shaft 25 can be kinematically connected to an electrical machine 9 of a transmission system 3.

[0045] For example, the first shaft 25 can thus be fixed in rotation around the axis of rotation AXROT to a first pinion 26 connected by a mechanical chain to the electric machine 9. According to the possibility illustrated on [Fig.1], the electric machine 9 comprises a power shaft 10 fixed to an input / output pinion 11 in mesh with the first pinion 26.

[0046] According to another aspect, the first tree 25 can be supported by a structure 200.

[0047] Such an electric machine 9 is configured to operate in a MODMOT motor mode to move the first shaft 25 and in a MODGEN electric generator mode by being moved by the first shaft 25.

[0048] For example, the electric machine 9 is typically controlled by a computer or a human-machine interface. The transmission system may include at least one sensor emitting a signal carrying information relating to the operation of the electric machine 9. For example, the system includes a current sensor measuring an electric current in the electric machine 9, a speed sensor measuring the rotational speed of an internal component of the electric machine 9, or others.

[0049] Furthermore, the second shaft 30 can be kinematically linked / connected to a mechanical device 4 of the transmission system 3 by conventional means.

[0050] According to another aspect, the linkage device 20 is equipped with a freewheel 35 interposed between the first shaft 25 and the second shaft 30. The freewheel 35 is configured to transmit a motor torque only from the first shaft 25 to the second shaft 30 during motor mode, when the first shaft rotates, in a direction called the "direction of rotation," around the axis of rotation AXROT. The freewheel is then synchronized. During motor mode, the first shaft 25 thus acts as a driving shaft, rotating, via the freewheel 35, the second shaft 30, which forms a driven shaft.

[0051] Such a freewheel 35 can be a conventional freewheel, with ramps or pawls for example. By way of illustration, the freewheel 35 can comprise an outer ring provided with ramps and fixed in rotation about the axis of rotation AXROT of the first shaft 25, an inner ring fixed in rotation about the axis of rotation AXROT of the second shaft 30, and rolling elements disposed between the outer ring and the inner ring.

[0052] Therefore, when the free wheel 35 is synchronized, the first shaft 25 rotates the second shaft 30 around the axis of rotation AX in the direction of rotation.

[0053] On the other hand, if the second shaft 30 rotates faster than the first shaft 25 in the direction of rotation, the free wheel 35 is desynchronized.

[0054] To rotate the first shaft 25 with the second shaft 30 around the axis of rotation AXROT and always in the direction of rotation during the electric generator mode, the linkage device 20 then includes a coupler 40. The term "coupler" designates a device configured to transmit a motor torque only from the second shaft 30 to the first shaft 25 during the electric generator mode, unlike the free wheel 35.

[0055] For this purpose, the linkage device 20 has a dog clutch link 50 configured to only transmit motor torque from the coupler 40 to the first shaft 25 during the electric generator mode.

[0056] Furthermore, the coupler is equipped with a fusible section 45 to disconnect the first shaft 25 from the second shaft 30, in the event of the first shaft 25 being blocked.

[0057] According to one possibility, the coupler 40 has an intermediate shaft 55 equipped with the fusible section 45. The fusible section 45 is obtained by locally reducing the thickness of the intermediate shaft 55 for example.

[0058] This intermediate shaft 55 can be fixed in rotation around the axis of rotation AXROT of the second shaft 30. According to the illustrated example, the intermediate shaft 55 has first splines 56 in contact with second splines 31 of the second shaft 30.

[0059] Furthermore, the dog clutch 50 serves to lock the intermediate shaft 55 and the first shaft 25, rotating about the axis of rotation AX, only during the electric generator mode and in the absence of a malfunction. Referring to [Fig. 2], the dog clutch 50 has at least a non-zero functional clearance 95, rotating about the axis of rotation AXROT in a direction of rotation 96, so as to prevent the first shaft 25 and the second shaft 30 from being locked in rotation during the motor mode, at least in the absence of a malfunction.

[0060] In particular, the dog clutch 50 comprises several first teeth 60 fixed to the first shaft 25 rotating about the axis of rotation AXROT. The first teeth can be arranged on a circle centered on the axis of rotation AXROT, by example in an equally distributed manner. Each first tooth 60 can extend from one end of the first shaft 25 parallel to the axis of rotation AXROT.

[0061] The dog clutch 50 also includes several second teeth 65 fixed to the intermediate shaft 55, which rotates about the axis of rotation AXROT. The second teeth 65 can be arranged on said circle centered on the axis of rotation AXROT, for example, in an evenly distributed manner. Each second tooth 65 can extend radially from the intermediate shaft 55 or from a disk 66 fixed to the intermediate shaft 55 with respect to the axis of rotation AXROT.

[0062] Each second tooth 65 is further arranged on an arc of a circle centered on the axis of rotation AXROT between a first upstream tooth 601 and a first downstream tooth 602. The expressions "upstream tooth" and "downstream tooth" are to be considered in the eyes of an observer 97 during a rotation around the axis of rotation AXROT of the first shaft 25 in the direction of rotation 96.

[0063] Each second tooth 65 is then separated from the corresponding first upstream tooth 601 by a clearance 95 sufficient to prevent the second tooth 65 from meshing with the associated first upstream tooth 601 during motor mode.

[0064] Furthermore and with reference again to [Fig. 1], the linkage device 20 may include an elastic return system 70 interposed between the intermediate shaft 55 and the second shaft 30 in order to position the first teeth 60 and the second teeth 65 on the same circle centered on the axis of rotation AXROT.

[0065] The elastic return system 70 is thus configured to push the coupler 40 into a predetermined POSCOUP coupling position allowing the dog clutch link 50 to transmit motor torque only from the coupler 40 to the first shaft 25.

[0066] Such an elastic return system 70 may include a spring 71 for example, or an equivalent.

[0067] According to the example illustrated in [Fig. 1], the spring 71 may comprise a coil in contact with or fixed to an internal disc 57 integral with the intermediate shaft 55, and a coil in contact with or fixed to a connecting disc 73. The connecting disc 73 may be fixed in translation parallel to the axis of rotation AXROT of the second shaft 30. For example, the connecting disc 73 is formed by a shoulder of a locking rod 72 passing through the spring 71. The locking rod 72 may have a fastening end 75 passing through a fastening disc 32 integral with the second shaft 30. A nut 74 may be screwed onto the fastening end 75 to be pressed against the fastening disc 32.

[0068] According to another aspect, the linkage device 20 may include an actuator 80 configured to move the coupler 40 in translation parallel to the axis of rotation AXROT from the coupling position POSCOUP to a decoupling position A predetermined POSDECOUP position inhibits the dog clutch linkage 50, and vice versa. In the POSDECOUP decoupling position, the first teeth 60 and the second teeth 65 are no longer located on the same circle centered on the AXROT rotation axis.

[0069] The actuator 80 can be controlled by a controller 82, such a controller 82 being able to include a human-machine interface and / or a standalone computer possibly linked to the aforementioned system monitoring sensors. For example, such a computer is configured to transmit a signal to the actuator in order to place the dog clutch linkage 50 in the POSDECOUP decoupling position in the event of a blockage or short circuit of the electric machine or during motor mode.

[0070] The actuator 80 shown is a hydraulic actuator comprising a standard hydraulic network (not shown) that is easily understood by those skilled in the art. Alternatively, the actuator 80 can be an electric or pneumatic cylinder, for example.

[0071] Figures 3 to 5 illustrate the operation of a linking device 20 according to the invention and an example of arrangement within a transmission system 3.

[0072] This transmission system 3 is equipped with a mechanical device 4 connected to a drive unit 6.

[0073] The drive installation 6 includes the electric machine 9 which can operate in a motor mode to move the mechanical device 4 and in an electric generator mode by being moved by the mechanical device 4.

[0074] The electric machine 9 is kinematically connected to the mechanical device 4 by a linkage device 20. In particular, the first shaft 25 is kinematically connected to the electric machine 9, and the second shaft 30 is kinematically connected to the mechanical device 4.

[0075] Optionally, the drive installation 6 includes at least one thermal engine 7 connected in the usual way to the mechanical device 4, possibly via a freewheel 8.

[0076] The transmission system 3 can be arranged within an aircraft 1. In particular, the mechanical device 4 can include a power transmission 5 driving at least one lift and / or propulsion rotor 2. The power transmission 5 can then be connected to the second shaft 30, or even to the internal combustion engine 7.

[0077] Figure 3 illustrates in particular a linkage device 20 without an actuator.

[0078] During motor mode, the electric machine 9 sets the first shaft in motion. 25 rotates the first shaft 25 around the axis of rotation AXROT. The linkage device 20 transmits mechanical power from the first shaft 25 to the second shaft 30, rotating in the direction of rotation 96, solely via the freewheel 35 as indicated by the dashed arrows. The clearance 95 prevents power transmission through the coupler 40. In addition, the second shaft 30 contributes to the movement of the power transmission box 5, jointly or not with the internal combustion engine 7. In the event of a blockage of the electrical machine 9, a rupture of the fuse section may occur and detach the electrical machine 9 from the mechanical device.

[0079] During the electric generator mode, the second shaft 30 is rotated by the mechanical device 4. As illustrated, the power transmission gearbox 5 is driven by the internal combustion engine 7 and causes the rotation of the second shaft 30 around its axis of rotation AXROT. The coupling device 20 transmits mechanical power from the second shaft 30 to the first shaft 25 solely via the coupler 40, as indicated by the solid arrows. The first shaft 25 then drives the input / output shaft 10 of the electric machine 9 in rotation.

[0080] In the event of a blockage of the electric machine 9, the fuse section 45 can break so as not to block the mechanical device 4. The use of a different power transmission path than in the context of the motor mode allows the placement of such a fuse section 45.

[0081] Figures 4 and 5 illustrate a variant of the linkage device 20 of [Fig.3] equipped with an actuator 80.

[0082] With reference to [Fig.4], the actuator 80 can position the coupler 40 in a POSCOUP coupling position. The linking device 20 then functions in the same way as in [Fig.3].

[0083] Upon command from a control 82, the actuator 80 can position the coupler 40 in a decoupling position POSDECOUP illustrated in [Fig. 5]. The coupler 40 is moved in translation parallel to the axis of rotation AXROT to inhibit the dog clutch 60. The elastic return system 70 is compressed. The electrical generator mode is then disabled for safety reasons.

[0084] Naturally, the present invention is subject to numerous variations in its implementation. Although several embodiments have been described, it is understood that it is not conceivable to exhaustively identify all possible embodiments. It is, of course, conceivable to replace a described means with an equivalent means without departing from the scope of the present invention and, in particular, the claims.

Claims

Claims

1. Transmission system (3) provided with a mechanical device (4) connected to a power plant (6), said power plant (6) comprising an electric machine (9) capable of operating in a motor mode for setting the mechanical device (4) in motion and in an electric generator mode by being set in motion by the mechanical device (4), the electric machine (9) being kinematically connected to the mechanical device (4) by a bidirectional connecting device (20), the connecting device (20) comprising a first shaft (25) kinematically connected to the electric machine (9) and a second shaft (30) kinematically connected to the mechanical device (4), the second shaft (30) being rotatable about an axis of rotation (AXROT) in a direction of rotation (96),the connecting device (20) comprising a freewheel (35) interposed between the first shaft (25) and the second shaft (30) for only transmitting a motor torque from the first shaft (25) to the second shaft (30) during the motor mode, characterized in that the bidirectional connecting device (20) comprises a coupler (40) provided with a fusible section (45), the coupler (40) being integral with the second shaft (30) rotating around said axis of rotation (AXROT), the connecting device (20) comprising a dog clutch connection (50) capable of only transmitting a motor torque from the coupler (40) to the first shaft (25) during the electric generator mode.,

2. Transmission system according to claim 1, characterized in that the coupler (40) comprises an intermediate shaft (55) provided with said fusible section (45) and secured to the second shaft (30) in rotation around the axis of rotation (AXROT), said intermediate shaft (55) being connected to the first shaft (25) by the dog connection (50), the dog connection (50) having at least one non-zero play (95) in rotation around the axis of rotation (AXROT) in the direction of rotation (96).

3. Transmission system according to claim 2, characterized in that said dog connection (50) comprises several first teeth (60) which are integral with the first shaft (25) rotating around the axis of rotation (AXROT) and several second teeth (65) which are integral with the intermediate shaft (55) rotating around the axis of rotation (AXROT), each second tooth (65) being arranged on an arc of a circle centered on the axis of rotation (AXROT) between a first upstream tooth (601) and a first downstream tooth (602) and being separated from the first upstream tooth (601) by a said clearance (95); the first upstream tooth (601) being upstream of the second downstream tooth (602) with regard to an observer (97) during a rotation in the direction of rotation around the axis of rotation (AXROT) of the first shaft (25).

4. Transmission system according to any one of claims 2 to 3, characterized in that said intermediate shaft (55) comprises first splines (36) meshing with second splines (56) of the second shaft (30).

5. Transmission system according to any one of claims 2 to 4, characterized in that said connecting device (20) comprises an elastic return system (70) interposed between the intermediate shaft (55) and the second shaft (30), the elastic return system (70) pushing the coupler (40) into a predetermined coupling position (POSCOUP) allowing the dog connection (50) to transmit a driving torque only from the coupler (40) to the first shaft (25).

6. Transmission system according to any one of claims 1 to 5, characterized in that said connecting device (20) comprises an actuator (80) configured to move the coupler (40) in translation from a predetermined coupling position (POSCOUP) allowing the dog connection (50) to transmit a driving torque from the coupler (40) to the first shaft (25) to a predetermined decoupling position (POSDECOUP) inhibiting the dog connection (50).

7. Transmission system according to any one of claims 1 to 6, characterized in that said power plant (6) comprises at least one thermal engine (7) kinematically connected to the mechanical device (4).

8. Aircraft (1), characterized in that said aircraft (1) comprises a transmission system (3) according to any one of claims 1 to 7.

9. Aircraft according to claim 8, characterized in that said mechanical device (4) comprises a box power transmission (5), the power transmission box (5) setting in motion at least one rotor (2) for lift and / or propulsion.

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