Hydraulic coupler for aircraft accessory drive gearbox

Abstract

Hydraulic coupler (10) for an aircraft accessory drive gearbox (1) comprising a housing (14), first (11) and second (12) turbines arranged in the housing, the first and second turbines being opposite each other and defining a coupling volume (13) within the housing, the coupling volume comprising a coupling fluid, in which the hydraulic coupler includes means (4) for emptying the coupling fluid from the coupling volume. Figure for the abbreviation: [Fig.1]

Description

Title of the invention: Hydraulic coupler for aircraft accessory drive gearbox Technical field of the invention

[0001] The invention relates to the field of accessory drive gearboxes within an aircraft. In particular, the invention relates to a hydraulic coupler for an aircraft accessory drive gearbox. Prior art

[0002] Accessory drive boxes, by drawing energy from a turbomachine, allow for the mechanical driving of equipment or accessories such as pumps, electric generators, etc., necessary for the operation of said turbomachine and / or the aircraft during a steady-state operating phase. Accessory drive boxes also allow for the mechanical driving of the turbomachine during its start-up phase.

[0003] In the case of hybridized turbomachinery, an electric machine is provided to inject energy into the turbomachine depending on the flight phase. When the electric machine is not used for hybridization, it draws energy from the turbomachine and thus functions as an electric generator. The electric machine is mechanically linked to the turbomachine by an accessory drive gearbox in a manner known per se. However, this alternation of the drawing and injection phases generates torque oscillations that can severely degrade components of the accessory drive gearbox.

[0004] Furthermore, it is also necessary to be able to control a mechanical disconnection of the electrical machine in the event of a fault (short circuit or other). This capability is commonly called "disconnect". An example of the implementation of such a function is described in document WO2019 / 149564. Description of the invention

[0005] An object of the invention is to provide a coupling device for an accessory, such as an electrical machine, minimizing the effects of torque oscillations while allowing decoupling of said accessory.

[0006] To this end, according to the invention, a hydraulic coupler is provided for an aircraft accessory drive gearbox, comprising a housing, first and second turbines formed within the housing, the first and second turbines being opposite each other and defining a coupling volume within the housing, the coupling volume comprising a coupling fluid, in which the coupler hydraulics includes means for emptying the coupling fluid from the coupling volume.

[0007] Advantageously, but optionally, the hydraulic coupler according to the invention has at least one of the following technical characteristics: • the means of emptying include a discharge pipe arranged so as to present a predetermined leakage rate; • The hydraulic coupler includes a coupling fluid supply line; the hydraulic coupler includes a pilot-operated valve provided on the supply line; and, • The means of emptying include a pilot-operated drain valve.

[0008] According to the invention, an aircraft accessory drive box is also provided in which the accessory drive box includes a hydraulic coupler having at least one of the preceding technical characteristics.

[0009] Advantageously, but optionally, the accessory drive box according to the invention has at least one of the following technical characteristics: - the hydraulic coupler is housed within the accessory drive box.

[0010] According to the invention, an aircraft turbomachine is also provided in which the turbomachine includes an accessory drive box having at least one of the preceding technical characteristics.

[0011] Advantageously, but optionally, the turbomachine according to the invention has at least one of the following technical characteristics:

[0012] - the turbomachine includes an accessory consisting of an electric machine coupled to the accessory drive gearbox via the hydraulic coupler.

[0013] The invention also provides a method for decoupling an accessory connected to an accessory drive gearbox via a hydraulic coupler having at least one of the preceding technical characteristics, wherein the method comprises the steps of: a. Triggering of accessory decoupling; b. Implementation of drainage means to evacuate the coupling fluid from the coupling volume of the hydraulic coupler.

[0014] Advantageously, but optionally, the method according to the invention has at least one of the following technical characteristics: • Step b) involves opening the pilot-operated drain valve; and, • step b) involves closing the supply line. Brief description of the figures

[0015] Other features and advantages of the invention will become apparent from the following description of an embodiment of the invention. See the accompanying drawings:

[0016] [Fig-1] is a schematic cross-sectional view of a hydraulic coupler according to the invention positioned between a drive box and an accessory;

[0017] [Fig.2] is a cross-sectional view of the hydraulic coupler of [Fig.1];

[0018] [Fig.3] is a partial three-dimensional cross-sectional view of an example embodiment of the assembly of [Fig. 1]; and,

[0019] [Fig.4] is a three-dimensional view of an accessory drive box comprising a hydraulic coupler according to the invention.

[0020]

[0021] For clarity, identical or similar elements are identified by identical reference signs throughout the figures. Detailed description of an implementation method

[0022] With reference to figures 1 to 3, we will describe an embodiment of a hydraulic coupler 10 according to the invention.

[0023] The hydraulic coupler 10 according to the invention is mounted here between a pinion output 110 of an accessory drive gearbox 1 and an accessory 2. In particular, accessory 2 is an electric machine. The hydraulic coupler 10 according to the invention allows power to be transmitted between the accessory drive gearbox 1 and accessory 2, and vice versa in the case where accessory 2 is an electric machine. The hydraulic coupler 10 according to the invention, the accessory drive gearbox 1, and accessory 2 are, in this instance, part of an aircraft turbomachine 100.

[0024] The hydraulic coupler 10 according to the invention is preferably integrated into the accessory drive gearbox 1. The hydraulic coupler 10 according to the invention comprises a housing 14. The hydraulic coupler 10 according to the invention further comprises, in a manner known per se, a first 11 and a second 12 turbine positioned opposite each other. The turbine 11, respectively 12, is connected to the pinion output 110 via a first shaft 111, respectively to an accessory shaft via a second shaft 1221. The first 11 and second 12 turbines move within the housing 14, which is partially filled with a coupling fluid, generally oil. Once positioned within the housing 14, the first 11 and second 12 turbines define, within the housing 14, a coupling volume 13 that receives the coupling fluid.

[0025] At the start of a power-storage phase (the turbomachine transmits power to the accessory 2 via the accessory drive gearbox 1), the first turbine 11 connected to the pinion output 110 is set in rotation. The first turbine 11 then drives the coupling fluid within the coupling volume as its rotational speed increases. Above a certain rotational speed, energy from the coupling fluid thus driven by the first turbine 11 is transferred. turbine 11 is sufficient to drive the second turbine 12, the latter being connected to the accessory 2. The power transmission is then carried out via the coupling fluid within the coupling volume 13, without any mechanical contact between the first 111 and second 112 shafts.

[0026] It should be noted that the hydraulic coupler 10 according to the invention can be used for any type of accessory 2 other than an electric machine.

[0027] For the injection phases where the accessory 2 (typically an electric machine) transmits power to the turbomachine via the accessory drive box 1, the operation of the hydraulic coupler 10 according to the invention is reversed: it is the second turbine 12 connected to the accessory 2 which is first set into rotational motion and this rotational motion is transmitted to the accessory drive box 1 via the coupling fluid within the coupling volume 13 and then to the first turbine 11 connected to the pinion output 110 of the accessory drive box 1.

[0028] The use of the hydraulic coupler 10 according to the invention allows power transmission by viscous friction with damping between the injection and extraction phases, significantly reducing problems related to torsional dynamics, since torque reverses more slowly and gradually. Furthermore, torque oscillations are greatly reduced thanks to the coupling fluid present in the coupling volume 13.

[0029] On the other hand, the hydraulic coupler 10 according to the invention includes means for emptying the coupling fluid from the coupling volume 13. These emptying means make it possible to perform a "disconnect" function by emptying the coupling fluid from the housing 14 and therefore from the coupling volume 13. If the coupling fluid is no longer present in the coupling volume 13, that is to say between the first 11 and second 12 turbines, there is no longer any power transmission and the accessory 2 is thus disengaged from the accessory drive gearbox 1.

[0030] According to a first embodiment illustrated in [Fig. 1], the hydraulic coupler 10 of the invention is fluidly connected to the accessory drive gearbox 1. In this embodiment, the hydraulic coupler 10 of the invention continuously receives oil from the accessory drive gearbox 1 via a supply line 3. The oil from the accessory drive gearbox 1 serves as the coupling fluid for the hydraulic coupler 10 of the invention. The draining means 4 here constitute a discharge line that allows the oil to be discharged from the crankcase 14 and returned to the accessory drive gearbox 1. Furthermore, the accessory drive gearbox 1 is fluidly connected to the oil system of the associated turbomachine via a supply circuit 5. The discharge line of the draining means 4 is arranged to exhibit a pre-calibrated leakage rate. This flow rate of A pre-calibrated leak allows for the regulation of the quantity of oil within the housing 14 and therefore within the coupling volume 13 of the hydraulic coupler 10 according to the invention, the oil serving as the coupling fluid for the operation of said hydraulic coupler 10 according to the invention. Additionally, the draining means 4 are associated with a pilot-operated valve provided on the inlet line 3. Closing this inlet line when the "disconnect" function is activated cuts off the oil supply to the hydraulic coupler 10 according to the invention, and the oil present is then drained from the coupling volume 13 according to the pre-calibrated leak rate via the discharge line.

[0031] In a second embodiment, the hydraulic coupler 10 according to the invention is not continuously supplied with oil. In this case, the draining means 4 comprise a pilot-operated drain valve whose opening allows the oil contained in the housing 14, and therefore in the coupling volume 13, of the hydraulic coupler 10 according to the invention to be drained when the "disconnect" function is activated. The oil contained in the housing 14 is then drawn by pumping means from a lubrication unit of the turbomachine and returns to the turbomachine's oil system. If coupling is again required between the accessory drive gearbox 1 and the accessory 2, the draining means 4 are then used intermittently to refill the housing 14 with oil in reverse operation.

[0032] With reference to [Fig. 4], the hydraulic coupler 10 according to the invention, in an embodiment illustrated herein, is integrated within the accessory drive gearbox 1 on one of the pinion outputs shown. It should be noted that more than one hydraulic coupler 10 according to the invention may be provided within the accessory drive gearbox 1. Such integration makes it possible to minimize the space occupied by the hydraulic coupler 10 according to the invention.

[0033] The use of such a hydraulic coupler 10 according to the invention makes it possible to achieve the required compactness, as the accessory drive gearbox 1 is increasingly intended to be located in the engine area, its size is a major consideration, especially as a control component. Furthermore, such an arrangement of the accessory drive gearbox 1 and one or more hydraulic couplers 10 according to the invention will allow for heat exchange between the oil circuit and a fuel circuit, improving the integration of these different systems as well as the compactness of other engine components.

[0034] It follows from the foregoing that the use of such a hydraulic coupler 10 according to the invention, particularly in a hybrid context, makes it possible to resolve problems related to torsional dynamics and the "disconnect" function: the hydraulic coupler 10 according to the invention transmits power from the accessory drive gearbox 1 to the accessory 2 and vice versa. The fact that the power that is transmitted only by the coupling fluid allows to absorb the torque oscillations and the emptying of the coupling fluid of the hydraulic coupler 10 according to the invention allows to realize the "disconnect" function.

[0035] Naturally, the invention is described above by way of example. It is understood that a person skilled in the art is able to carry out different embodiments of the invention without departing from the scope of the invention.

[0036] It is emphasized that all features, as they are apparent to a person skilled in the art from the present description, drawings and attached claims, even if in practice they have only been described in relation to other specific features, both individually and in any combinations, may be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances make such combinations impossible or meaningless.

Claims

Demands

1. Hydraulic coupler (10) for an aircraft accessory drive box (1), comprising a housing (14), first (11) and second (12) turbines provided in the housing, the first and second turbines being opposite each other and defining a coupling volume (13) within the housing, the coupling volume comprising a coupling fluid, wherein the hydraulic coupler includes means for emptying (4) the coupling fluid from the coupling volume.

2. Hydraulic coupler according to claim 1, wherein the discharge means comprise a discharge conduit arranged to exhibit a predetermined leakage rate.

3. Hydraulic coupler according to claim 2, wherein the hydraulic coupler comprises a coupling fluid supply line (3).

4. Hydraulic coupler according to claim 3, wherein the hydraulic coupler comprises a piloted valve provided on the supply line.

5. Hydraulic coupler according to claim 1, wherein the discharge means comprise a piloted discharge valve.

6. Aircraft accessory drive box (1) wherein the accessory drive box comprises a hydraulic coupler (10) according to any one of claims 1 to 5.

7. Accessory drive box according to claim 6, wherein the hydraulic coupler is provided within the accessory drive box.

8. Aircraft turbomachine (100) wherein the turbomachine includes an accessory drive box (1) according to any one of claims 6 to 7.

9. Turbomachine according to claim 8, wherein the turbomachine includes an accessory (2) consisting of an electric machine coupled to the accessory drive box via the hydraulic coupler (10).

10. A method for decoupling an accessory (2) connected to an accessory drive gearbox (1) via a hydraulic coupler according to any one of claims 1 to 5, wherein the method comprises the steps of: a. Triggering of a decoupling of the accessory; b. Implementation of the emptying means (4) to evacuate the coupling fluid from the coupling volume (13) of the hydraulic coupler.

11. Decoupling method according to claim 10, wherein, the hydraulic coupler being according to claim 5, step b) includes an opening of the piloted drain valve.

12. Decoupling method according to claim 10, wherein, the hydraulic coupler being according to any one of claims 3 to 4, step b) comprises a closure of the supply line.