AIRCRAFT TURBOMACHINE

Abstract

Aircraft turbomachine (1) (2) comprising: - a propulsion rotor (3) including at least one variable-pitch blade (4); - a blade (4) pitch adjustment device (6), this adjustment device (6) including a hydraulic actuator (9) controlled by a main hydraulic circuit (11) and an auxiliary hydraulic circuit (12), the main circuit (11) being supplied by a main oil reservoir (14) and including a blade (4) pitch adjustment pump (15), the main and auxiliary circuits (11, 12) having a common section (13); - a blade (4) pitch locking device (16); characterized in that the main circuit (11) includes a shut-off valve (17) configured to occupy an inactive position and an active position in which the shut-off valve (17) hydraulically isolates the adjustment pump (15) from the main reservoir (14). Figure for the abstract: 2

Description

Title of the invention: AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The present invention relates to an aircraft turbomachine comprising a propulsion rotor having at least one variable pitch blade, a blade pitch adjustment device and a blade pitch locking device. Technical background

[0002] An aircraft turbomachine may include a propulsion rotor equipped with variable pitch blades, i.e. blades whose pitch (and more precisely the pitch angle) is adjustable according to flight parameters, in order to optimize the performance of the turbomachine.

[0003] By way of example, the propulsion rotor can be a blower or a propeller which is driven into rotation by a power turbine of the turbomachine via a speed reducer.

[0004] Such a turbomachine includes a blade pitch adjustment device. The adjustment device includes one or more actuators and a mechanism specific to each blade, this mechanism being configured to transform the movement initiated by the actuator(s) into a rotational movement of the corresponding blade.

[0005] Traditionally, the actuator(s) are hydraulic actuators controlled by a main hydraulic circuit and an auxiliary hydraulic circuit.

[0006] The auxiliary circuit is used to put the blades in the feathered position in the event of a failure of the main circuit. The main and auxiliary circuits generally have a common section which includes, in particular, a control unit, an oil transfer device, and the hydraulic actuator(s).

[0007] The main circuit is supplied by a main oil reservoir and includes, in particular, a blade pitch adjustment pump which is mechanically driven by the turbomachine's accessory gearbox. The main oil reservoir is also used to supply the turbomachine's lubrication circuit, this lubrication circuit being used, in particular, to lubricate the speed reducer (gears and bearings) and bearings guiding various shafts of the turbomachine.

[0008] A hydraulic leak in the common section of the main and auxiliary circuits is a possible failure that would render both circuits unusable. The blades would then be free to move around their axis of rotation, which is undesirable (risk of significant drag and / or rotor overspeed). To prevent this, it is known to implement a locking device specific to each blade; these devices locking being configured to lock the blade alignment, in particular in the event of a simultaneous failure of both circuits.

[0009] Engine manufacturers note that it is also essential to quickly stop this hydraulic leak, otherwise the main reservoir may be partially or completely emptied. The main reservoir, it should be noted, is also used by the lubrication system. A low oil level in the main reservoir could damage the gearbox and the various bearings due to suboptimal or nonexistent lubrication.

[0010] The objective of the present invention is therefore to provide a simple, effective and economical solution to the aforementioned problem. Summary of the invention

[0011] The invention thus proposes an aircraft turbomachine comprising: - a propulsion rotor comprising at least one variable-pitch blade; - a blade pitch adjustment device, this adjustment device being integral with the rotor and comprising a hydraulic actuator controlled by a main hydraulic circuit and an auxiliary hydraulic circuit, the main circuit being supplied by a main oil reservoir and comprising a blade pitch adjustment pump, the auxiliary circuit being intended for putting the blade in the feather position, the main and auxiliary circuits having a common part; - a blade timing locking device configured to occupy an inactive position and an active position in which the locking device locks the blade timing, particularly in the event of a hydraulic leak in the common part of the circuits; characterized in that the main circuit includes a shut-off valve configured to occupy an inactive position and an active position in which the shut-off valve hydraulically isolates the main reservoir's regulating pump, particularly in the event of a hydraulic leak in the common part of the circuits.

[0012] Such a shut-off valve, in its active position, allows the regulating pump to be hydraulically isolated from the main reservoir by blocking the flow of oil. This is particularly advantageous in the event of a hydraulic leak in the common section of the circuits, so as not to empty the main reservoir, and thus allowing the various components (gearbox, bearings, etc.) of the lubrication circuit to continue to be properly lubricated.

[0013] The turbomachine according to the invention may comprise one or more of the following features, taken individually or in combination with each other: - the shut-off valve is located between the main tank and the regulating pump; - the main circuit includes a fuel pump, the shut-off valve being located between the fuel pump and the regulating pump; - the propulsion rotor is driven in rotation by a power turbine via a speed reducer, the reducer being lubricated via a lubrication circuit which is supplied by the main reservoir; - the turbomachine includes several bearings configured to guide in rotation several moving shafts of the turbomachine, the bearings being lubricated via the lubrication circuit; - the common part of the circuits includes a control unit, an oil transfer bearing and the actuator, the control unit being controlled by a turbomachine control computer; - the regulating pump is mechanically driven by an accessory gearbox of the turbomachine, the accessory gearbox itself being mechanically driven by a gas generator of the turbomachine; - the auxiliary circuit is supplied by an auxiliary oil reservoir and includes an auxiliary pump mechanically driven by an electric motor; - the locking device and the shut-off valve are in an active position when the oil pressure in the common part of the circuits is below a predetermined threshold value; - oil pressure is measured redundantly by two independent pressure sensors; - the shut-off valve is redundantly controlled by a control unit which is common to the main and auxiliary circuits, and / or a turbomachine control computer; - the propulsion rotor is a propulsion blower or a propulsion propeller. Brief description of the figures

[0014] The invention will be better understood and other details, features and advantages of the invention will become more apparent upon reading the following description, given by way of non-limiting example and with reference to the accompanying drawings in which:

[0015] [Fig-1] [Fig.1] is a schematic view of an aircraft turbomachine according to the invention;

[0016] [Fig.2] [Fig.2] is a schematic detail view of [Fig.1];

[0017] [Fig.3] [Fig.3] is a schematic view similar to [Fig.2] which illustrates a alternative implementation. Detailed description of the invention

[0018] Figure [Fig.1] schematically and partially represents a turbomachine 1 of aircraft 2 which is defined along a longitudinal axis X.

[0019] The turbomachine 1 comprises a propulsion rotor 3 which is free to rotate about the X-axis relative to a fixed structure of the turbomachine 1. The rotor 3 comprises an annular array of variable-pitch blades 4, each blade 4 being pitched about an axis of rotation Y which is substantially perpendicular to the X-axis. The rotor 3 is driven in rotation by a power turbine associated with a gas generator of the turbomachine 1. The power turbine and the gas generator are not shown in the figures for clarity.

[0020] The propulsion rotor 3 can be a shrouded fan, and thus be part of a turbojet, for example a UHBR type turbojet for “Ultra High Bypass Ratio”.

[0021] The propulsion rotor 3 can be an unducted fan, and thus be part of a UDF type "Unducted Fan", USF type "Unducted Single Fan", or "Open Rotor" type turbomachine.

[0022] The rotor 3 can also be a shrouded or unshrouded propeller.

[0023] The turbomachine could comprise two or more propulsion rotors 3 which are counter-rotating or not.

[0024] The rotor(s) 3 can be arranged upstream or downstream of the assembly comprising the gas generator and the power turbine.

[0025] According to the embodiments illustrated in the figures, the rotor 3 is driven in rotation by the power turbine via a speed reducer 5. The speed reducer 5 reduces the rotational speed of the rotor 3 relative to that of the power turbine, while simultaneously increasing its torque. The speed reducer 5 is, for example, an epicyclic gear reducer, which has the advantage of a high reduction ratio while remaining compact.

[0026] The gas generator conventionally comprises, from upstream to downstream, at least one compressor, one combustion chamber, and at least one expansion turbine (or high-pressure turbine). The compressor and the expansion turbine are rotationally linked to each other via a drive shaft.

[0027] The power turbine is independent of the gas generator, and in other words the power turbine is not rotationally linked with the gas generator.

[0028] The rotor 3 can operate in "propulsion mode" so as to propel or move aircraft 2 forward, and in "reversing mode" so as to brake aircraft 2 at the time of its landing.

[0029] The turbomachine 1 includes a fan pitch adjustment device 6 for the blades 4, better known by the English acronyms FPAS for "Fan Pitch Actuation System" or PCM for "Pitch Change Mechanism". The fan pitch adjustment device 6 is integral with the rotor 3 and is therefore located in a rotating frame 7. The fan pitch adjustment device 6 includes one or more hydraulic actuators 9 and a mechanism 10 specific to each of the blades 4, this mechanism 10 being configured to transform the movement initiated by the actuator(s) 9 into a rotational movement of the corresponding blade 4. The movement of the actuator(s) 9 thus allows for the synchronized adjustment of the timing of all the blades 4 via, in particular, the various mechanisms 10.

[0030] The hydraulic actuator 9 can be linear or rotary.

[0031] According to the embodiments illustrated in the figures, and in particular in [Fig. 1], the adjustment device 6 comprises a single actuator 9, which is a hydraulic and linear cylinder. Each mechanism 10 may include, in particular, a crank having a first end connected to a pivot of the blade and a second end (eccentric with respect to the first end) connected to a synchronizing ring, which is controlled by the actuator 9.

[0032] The actuator(s) 9 are controlled by a main hydraulic circuit 11 and an auxiliary hydraulic circuit 12. The auxiliary circuit 12 is used to put the blades 4 in the feathering position in the event of a failure of the main circuit 11. The main and auxiliary circuits 11, 12 have a common section 13 which includes various hydraulic components useful to both circuits 11, 12. The main circuit 11 is supplied by a main oil reservoir 14 and includes a pump 15 for adjusting the blade pitch of the blades 4.

[0033] The turbomachine 1 also includes a locking device 16 for the blade positioning 4. This locking device 16 may be common to all the blades 4 or specific to each of the blades 4.

[0034] According to the embodiments illustrated in the figures and in particular in [Fig.1], each blade 4 is associated with a locking device 16. The locking device 16 is configured to occupy an inactive position in which the locking device 16 allows the blade 4 to be set, and an active position in which the locking device 16 locks the blade 4 to be set, in particular in the event of a hydraulic leak in the common part 13 of the circuits 11, 12.

[0035] More generally, the various locking devices 16 are in the active position when both the main and auxiliary circuits 11,12 fail simultaneously, to avoid excessive drag and / or overspeed of the rotor 3.

[0036] By way of example, a locking device 16 comprises a disc linked to the blade, this disc being inserted between two jaws fixed to a ring carrying the blade, one of the jaws being fixed, the other being movable and controlled by an actuator. In the active position, the jaws clamp the disc under the impulse of the actuator.

[0037] According to the invention, the main circuit 11 includes a shut-off valve 17 (or isolation valve) configured to occupy an inactive position and an active position in which the shut-off valve 17 hydraulically isolates the regulating pump 15 from the reservoir main 14, in particular in the event of a hydraulic leak in the common part 13 of circuits 11, 12.

[0038] Such a shut-off valve 17, in its active position, allows the regulating pump 15 to be hydraulically isolated from the main reservoir 14 by blocking the flow of oil. This is particularly advantageous in the event of a hydraulic leak in the common section 13 of the circuits 11, 12, so as not to empty the main reservoir 14, and thus allowing the various components (gearbox, bearings, etc.) of the lubrication circuit to continue to be properly lubricated.

[0039] By convention, in the present application, the terms "upstream" and "downstream" are defined with respect to the direction of gas flow in the turbomachine 1 and the direction of oil flow in each of the circuits 11, 12, 19.

[0040] Advantageously, the shut-off valve 17 is located between the main reservoir 14 and the regulating pump 15.

[0041] The main circuit 11 may include a feed pump 18 (or booster pump) upstream of the regulating pump 15. The shut-off valve 17 is then located between the feed pump 18 and the regulating pump 15.

[0042] The turbomachine 1 may include a lubrication circuit 19 which is separate from the main and auxiliary circuits 11, 12. The lubrication circuit 19 is supplied by the main oil reservoir 14 and is used in particular to lubricate the speed reducer 5 (gears and bearings) and bearings 20 guiding various moving shafts of the turbomachine 1.

[0043] The common part 13 of the circuits 11,12 may include a control unit 21 and / or an oil transfer bearing 22 (rotating fitting or rotating joint).

[0044] The control unit 21 is also known by the English acronym PCU for "Power Control Unit". The control unit 21 allows, in particular, the distribution of pressurized oil via various distributors. The control unit 21 is controlled by a control computer 23 of the turbomachine 1, this computer 23 being more commonly known by the English acronym FADEC for "Full Authority Digital Engine Control". Advantageously, the control computer 23 comprises two separate channels operating in parallel, to ensure redundancy in the event of a failure of either channel.

[0045] The oil transfer bearing 22 is also known by the English acronym OTB for "Oil Transfer Bearing". The oil transfer bearing 22 allows the oil to be transferred from the fixed reference mark 8 (attached to the structure) to the rotating reference mark 7 (attached to the rotor 3).

[0046] Advantageously, the regulating pump 15 is mechanically driven by an accessory gearbox 24 of the turbomachine 1. The accessory gearbox 24 is also known by the English acronym AGB for "Accessory Gear Box". In the conventional way, the accessory box 24 is mechanically driven by the gas generator of the turbomachine 1.

[0047] Advantageously, the auxiliary circuit 12 is supplied by an auxiliary oil reservoir 25 (separate from the main oil reservoir 14) and includes an auxiliary pump 26 mechanically driven by an electric motor 27.

[0048] Advantageously, the locking devices 16 and the shut-off valve 17 are in an active position when the oil pressure in the common section 13 of the circuits 11, 12 is below a predetermined threshold (or reference) value. The oil pressure is preferably measured redundantly by two independent pressure sensors, each pressure sensor being connected to the control unit 21 and / or to one of the channels of the control computer 23.

[0049] The shut-off valve 17 can be redundantly controlled by the control unit 21 and / or the control computer 23.

[0050] Advantageously, the shut-off valve 17 is tested before each flight of the aircraft 2, to verify its proper functioning.

[0051] According to the embodiments illustrated in the figures, and in particular figures 2 and 3, the main circuit 11 comprises successively, from the main reservoir 14 to the common part 13 of the circuits 11, 12, a volumetric lift pump 18, a filter 28, an air / oil heat exchanger 29, the shut-off valve 17 and the regulating pump 15. The main circuit 11 further comprises a bypass valve 30 in parallel with the shut-off valve 17 and the regulating pump 15.

[0052] The feed pump 18 and the adjustment pump 15 are mechanically driven by the accessory housing 24 of the turbomachine 1.

[0053] As illustrated in Figures 2 and 3, the auxiliary circuit 12 comprises successively, from the auxiliary reservoir 25 to the common part 13 of the circuits 11, 12, an auxiliary volumetric pump 26 and a bypass valve 31.

[0054] The auxiliary pump 26 is mechanically driven by an electric motor 27.

[0055] As illustrated in more detail in [Fig. 1], the common part 13 of the circuits 11,12 comprises successively a control unit 21, an oil transfer bearing 22 and the hydraulic cylinder (adjustment device 6).

[0056] As illustrated in Figures 2 and 3, the turbomachine 1 comprises a lubrication circuit 19 which includes successively, from the main reservoir 14 to the bearings 20 and the gearbox 5 to be lubricated, a supply pump 32, a filter 33, an air / oil heat exchanger 34 and two fuel / oil heat exchangers 35. The speed reducer 5 is supplied via a branch or connection located between the two fuel / oil heat exchangers 35.

[0057] Figure 1 illustrates, by means of dotted lines, the different elements located in the fixed frame 8 (linked to the fixed structure) and the different elements located in the Rotating datum 7 (linked to rotor 3). The oil transfer bearing 22 straddles the fixed datum 8 and the rotating datum 7 because it comprises a fixed component attached to the fixed datum 8 and a movable component attached to the rotating datum 7, to allow the transfer of oil from the fixed datum 8 to the rotating datum 7. The fixed datum 8 includes, in particular, the main reservoir 14, the feed pump 18, the regulating pump 15, the shut-off valve 17, the control unit 21, and the control computer 23. The rotating datum 7 includes, in particular, the drive rotor 3, the regulating device 6 (actuator 9 and mechanisms 10), and the locking devices 16.

[0058] As illustrated in [Fig. 1], the control unit 21 is controlled by a FADEC-type control computer 23, which is described above. The control computer 23 receives information on the blade positioning 4 via various angular position sensors 36.

[0059] The shut-off valve 17 can occupy an inactive position in which it allows the passage of oil and an active position in which it blocks the passage of oil, so as to hydraulically isolate the regulating pump 15 from the main reservoir 14.

[0060] As indicated above, the shut-off valve 17 is in an active position in the event of a hydraulic leak in the common section 13 of the circuits 11, 12, and for example, a leak at the control unit 21 or the oil transfer bearing 22 or the actuator 9, or even at a line connecting the aforementioned components. The shut-off valve 17 can also be in an active position when one of the hydraulic components of the common section 13 is faulty.

[0061] According to the embodiment illustrated in Figures 1 and 2, the shut-off valve 17 is redundantly controlled by the FADEC-type control unit 23. As indicated above, the control unit 23 comprises two separate channels operating in parallel, to ensure redundancy in the event of a failure of either channel.

[0062] According to the embodiment illustrated in [Fig.3], the stop valve 17 is redundantly controlled by the control unit 21.

Claims

Demands

1. Aircraft turbomachine (1) (2) comprising: - a propulsion rotor (3) including at least one variable-pitch blade (4); - a blade (4) pitch adjustment device (6), this adjustment device (6) being integral with the rotor (3) and including a hydraulic actuator (9) controlled by a main hydraulic circuit (11) and an auxiliary hydraulic circuit (12), the main circuit (11) being supplied by a main oil reservoir (14) and including a blade (4) pitch adjustment pump (15), the auxiliary circuit (12) being intended for feathering the blade (4), the main and auxiliary circuits (11, 12) having a common part (13);- a locking device (16) for the blade (4) timing configured to occupy an inactive position and an active position in which the locking device (16) locks the blade (4) timing, particularly in the event of a hydraulic leak in the common part (13) of the circuits (11, 12); characterized in that the main circuit (11) includes a shut-off valve (17) configured to occupy an inactive position and an active position in which the shut-off valve (17) hydraulically isolates the regulating pump (15) from the main reservoir (14), particularly in the event of a hydraulic leak in the common part (13) of the circuits (11, 12).

2. Turbomachine (1) according to claim 1, characterized in that the shut-off valve (17) is located between the main tank (14) and the regulating pump (15).

3. Turbomachine (1) according to the preceding claim, characterized in that the main circuit (11) includes a feed pump (18), the shut-off valve (17) being located between the feed pump (18) and the regulating pump (15).

4. Turbomachine (1) according to any one of the preceding claims, characterized in that the propulsion rotor (3) is driven into rotation by a power turbine via a speed reducer (5), the reducer (5) being lubricated via a lubrication circuit (19) which is supplied by the main tank (14).

5. Turbomachine (1) according to the preceding claim, characterized in that the turbomachine (1) comprises several bearings (20) configured to guide in rotation several moving shafts of the turbomachine (1), the bearings (20) being lubricated via the lubrication circuit (19).

6. Turbomachine (1) according to any one of the preceding claims, characterized in that the common part (13) of the circuits (11, 12) comprises a control unit (21), an oil transfer bearing (22) and the actuator (9), the control unit (21) being controlled by a control computer (23) of the turbomachine (1).

7. Turbomachine (1) according to any one of the preceding claims, characterized in that the regulating pump (15) is mechanically driven by an accessory box (24) of the turbomachine (1), the accessory box (24) itself being mechanically driven by a gas generator of the turbomachine (1).

8. Turbomachine (1) according to the preceding claim, characterized in that the auxiliary circuit (12) is supplied by an auxiliary oil reservoir (25) and includes an auxiliary pump (26) mechanically driven by an electric motor (27).

9. Turbomachine (1) according to any one of the preceding claims, characterized in that the locking device (16) and the shut-off valve (17) occupy an active position when the oil pressure in the common part (13) of the circuits (11, 12) is less than a predetermined threshold value.

10. Turbomachine (1) according to the preceding claim, characterized in that the oil pressure is measured redundantly by two independent pressure sensors.

11. Turbomachine (1) according to any one of the preceding claims, characterized in that the shut-off valve (17) is redundantly controlled by a control unit (21) which is common to the main and auxiliary circuits (11, 12), and / or a control computer (23) of the turbomachine (1).

12. Turbomachine (1) according to any one of the preceding claims, characterized in that the propulsion rotor (3) is a propulsion blower or a propulsion propeller.

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