TURBOMACHINE MODULE EQUIPPED WITH A HYDRAULIC ACCUMULATOR AND TURBOMACHINE CONTAINING IT

Abstract

The invention relates to a turbomachine module comprising: - variable-pitch blades; - a power shaft (7) driving the blades via a speed reducer (9); - a pitch-changing system (15) comprising a linkage mechanism (16) connected to the blades and a control means (17) acting on the linkage mechanism (16); and - a pressurized fluid supply system (19) comprising a main circuit (21) for supplying the control means, the main circuit comprising a main feed pump (22) connected to a power source (18) and driven by the power shaft. According to the invention, the supply system comprises a hydraulic accumulator (27) storing hydraulic fluid, the hydraulic accumulator (27) being connected to the main circuit and intended to supply the control means when the main feed pump is inactive for driving the blades into the feathered position.Figure for the abbreviation: Figure 2.

Description

Title of the invention: TURBOMACHINE MODULE EQUIPPED WITH A HYDRAULIC ACCUMULATOR AND TURBOMACHINE CONTAINING IT Scope of the invention

[0001] The present invention relates to the field of turbomachinery equipped with variable pitch blades. State of the art

[0002] Variable-pitch or variable-speed turbine blades used on turbomachinery improve their performance under various flight conditions. Turbomachinery incorporates a pitch control system to change the blade orientation to several positions. Variable-pitch blades can, in particular, occupy a "feathered" position, where the blade is oriented in the direction of the airflow to reduce drag, and a "reverse" position, where the blade is positioned transversely to the flow to slow the aircraft, for example.

[0003] It is intended that the variable pitch blades will automatically occupy the feathering position in the event of a failure in the turbomachine or malfunction of the pitch change system regardless of the operating regime of the turbomachine.

[0004] The pitch change system may include an electric actuator or a hydraulic actuator. The hydraulic actuator is actuated by a pressurized fluid and is particularly advantageous in turbomachinery and aircraft subjected to high aerodynamic stress for controlling blade position and feathering.

[0005] The pressurized fluid comes from a main feed pump connected to a power source and driven by a shaft of the turbomachine. In the event of a failure in the turbomachine, the main pump can no longer supply the hydraulic power required to operate the hydraulic actuator. Generally, the turbomachine also includes an auxiliary electric feed pump to compensate for a failure in the turbomachine and to drive the variable-pitch blades into the feathered position. The turbomachine further includes a secondary pump connected to the same power source and intended to lubricate components of the turbomachine.

[0006] However, the auxiliary pump must be able to pump the feed fluid to the actuator when the turbomachine is not operating. This constraint This requires modifications to the turbomachine casings to accommodate piping between the main pump and the main reservoir, or a dedicated pressurized reservoir for the auxiliary pump with a sufficient fluid volume to operate the variable-pitch blades. These constraints can complicate the integration and geometry of the gearbox casings that support these systems. Furthermore, the electric auxiliary pump, in the form of a battery, can increase the turbomachine's overall weight. Summary of the invention

[0007] The present invention aims in particular to provide a solution enabling autonomous power supply to a control means for the feathering position of variable pitch blades in case of failure.

[0008] We achieve this objective, in accordance with the invention, by means of a turbomachine module comprising:

[0009] - a plurality of variable-pitch blades, - a power shaft driving the variable-pitch blades via a speed reducer, - a pitch change system comprising a linkage mechanism connected to the variable-pitch blades and a hydraulic control means acting on the linkage mechanism; and - a pressurized fluid supply system comprising a main circuit intended to supply the hydraulic control means, the main circuit comprising a main supply pump which is connected to a power source and which is driven by the power shaft, the supply system comprising a hydraulic accumulator configured to store a hydraulic fluid, the hydraulic accumulator being on the one hand connected to the main circuit and on the other hand intended to supply the control means when the main supply pump is inactive so as to drive the variable pitch vanes into the feathering position.

[0010] Thus, this solution makes it possible to achieve the aforementioned objective. In particular, the hydraulic accumulator is a completely self-contained device that actuates the control means so that the variable-pitch blades assume the feathered position in the event of a turbomachine failure, or even a failure of the feed pump. The accumulator's configuration eliminates the need for various additional pipes or reservoirs to supply the control means, resulting in weight and cost savings. More precisely, the accumulator is lighter than a prior art auxiliary pump.

[0011] The blower module also includes one or more of the following features, taken alone or in combination:

[0012] - the hydraulic accumulator is associated with a regulating device which is configured to occupy at least: - a closed position in which the regulating device blocks the passage of hydraulic fluid from the hydraulic accumulator to the control means; and

[0013] - -an open position in which the regulatory device allows the passage of hydraulic fluid from the hydraulic accumulator to the control means.

[0014] - the regulating device is in the open position when the pressure decreases in the main circuit to reach a predetermined value.

[0015] - the main circuit includes a conduit directly connecting the means of control to the main feed pump and in that an auxiliary pipeline directly connects the hydraulic accumulator to the pipeline.

[0016] - the regulating device includes a non-return valve arranged between an orifice of outlet of the hydraulic accumulator and the auxiliary pipeline.

[0017] - the hydraulic accumulator is installed outside a lubrication chamber in which the speed reducer is arranged.

[0018] - the hydraulic fluid stored in the hydraulic accumulator is identical to the fluid circulating at least in the main circuit.

[0019] - the hydraulic fluid is intended to be pressurized by an inert gas.

[0020] - the accumulator includes means for pressurizing the hydraulic fluid.

[0021] -the accumulator includes a chamber containing an inert gas intended to pressurize the hydraulic fluid.

[0022] - the module includes a secondary pump connected to the power supply and connected to the main feed pump via a connecting pipe, the secondary pump is intended to lubricate components and / or equipment of the tur-bomachine.

[0023] The invention also relates to an aircraft turbomachine comprising a turbomachine module having any of the preceding characteristics.

[0024] The invention further relates to an aircraft comprising a turbomachine as mentioned above. Brief description of the figures

[0025] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent upon reading the following detailed explanatory description, of embodiments of the invention given by way of purely illustrative and non-limiting examples, with reference to the following attached figures:

[0026] Figure 1 is a schematic, axial, partial cross-sectional view of a turbomachine to which the invention applies; and

[0027] Figure 2 schematically represents a power supply system for a pitch change system equipping a turbomachine according to the invention. Detailed description of the invention

[0028] The invention applies to any turbomachine comprising a plurality of variable pitch blades.

[0029] Fig. 1 shows an axial and partial cross-sectional view of a turbomachine 1 with longitudinal axis X.

[0030] The illustrated turbomachine 1 is a turboprop equipped with a single annular row of unfaired variable-pitch blades 2 forming a propeller. The turboprop is intended for mounting on an aircraft. The turboprop may include a pair of unfaired, counter-rotating propellers. These turboprops are known by the English term "open rotor".

[0031] Of course, the turbomachine can be a single-flow or double-flow turbojet with variable-pitch blades that are shrouded and form a fan.

[0032] Generally speaking and in the rest of the description, the term "propeller" is used to refer indifferently to a blower or a propeller.

[0033] In the present application, the terms "upstream", "downstream", "axial" and "axially" are defined with respect to the direction of gas flow in the turbomachine and also along the longitudinal axis X. The terms "radial", "radially", "internal" and "external" are also defined with respect to a radial axis Z which is perpendicular to the X axis of the turbomachine.

[0034] The turbomachine 1 comprises a gas generator 3 or gas turbine engine generally including a compressor assembly, a combustion chamber, and a turbine assembly. The variable-pitch blades 2 are mounted upstream of the gas generator 3. The variable-pitch blades 2 can be mounted downstream of the gas generator, particularly in the case of a turboprop with a propeller pair.

[0035] The variable-pitch blades 2 each comprise a foot 4 and a blade 5 extending radially outwards. Each foot 4 is received in a corresponding recess in a support ring 6 centered on the longitudinal axis X. In other words, the support ring 6 comprises several recesses distributed around its periphery. In particular, the foot 4 of each variable-pitch blade 2 is pivotally mounted so that the blade 2 is rotatable about a pitch axis A. The pitch axis A is here substantially (+ / - 5°) parallel to the radial axis Z.

[0036] The turbomachine 1 includes a power shaft 7 which drives the pitching blades variable 2 around the longitudinal axis X. Advantageously, but not limitingly, the variable pitch blades 2 are carried by a propeller shaft 8. The latter is driven in rotation by the power shaft 7 and is fixed to the support ring 6.

[0037] The turbomachine 1 may include a speed reducer 9 arranged between the propeller shaft 8 and the power shaft 7. The speed reducer 9 is intended to be driven by the power shaft 7 and to rotate the propeller shaft 8 at a speed different from that of the power shaft 7.

[0038] The speed reducer 9 may include a planetary or epicyclic gear train in the field of turbomachinery. Advantageously, the gear train typically includes a sun gear (or internal planet gear), a plurality of planet gears, a planet carrier, and a ring gear (outer planet gear).

[0039] In the case of a planetary-type speed reducer, the sun gear is centered on the longitudinal axis X and is rotationally coupled to the turbomachine's power shaft 7. The planet carrier is fixed against rotation and is integral with a fixed structure of the turbomachine. Finally, the ring gear is centered on the longitudinal axis X and is rotationally coupled to the propeller shaft 8.

[0040] In the case of an epicyclic speed reducer, the solar element is coupled to the power shaft 7, the planet carrier is rotationally coupled to the propeller shaft 8, and the ring gear is fixed to the stationary structure of the turbomachine. In other words, the ring gear is rotationally fixed.

[0041] The speed reducer 9 is housed in a lubrication enclosure 10. In the present example, the enclosure 10 is arranged upstream of the gas generator 3. The lubrication chamber 10 allows lubrication of the speed reducer 9 as well as the rotational guide bearings of the speed reducer 9 and the propeller shaft 8.

[0042] Advantageously, but not limitingly, the enclosure 10 is delimited by an annular housing 11 which is integral with a fixed structure of the turbomachine 1. The annular housing 11 is formed for example of bearing support 12 upstream and possibly downstream of the speed reducer 9.

[0043] With reference to [Fig.2], the turbomachine 1 advantageously includes a pitch change system 15 for changing the pitch or orientation of the blades around their pitch axis A. This allows the blades 5 to be oriented into a desired angular position according to the operating conditions of the turbomachine and the different phases of flight.

[0044] In the present example, the pitch change system 15 is arranged along the longitudinal axis of the turbomachine 1. More specifically, the pitch change system 15 is advantageously mounted upstream of the speed reducer 9. The pitch change system 15 is advantageously mounted on the propeller shaft 8, between the propeller and the speed reducer 9 along the longitudinal axis X.

[0045] Each blade 5 can pivot between an extreme working position (thrust reversal position, known in English as "reverse") and an extreme feathering position. In particular, in the extreme thrust reversal position, the propeller blades 5 contribute to the aircraft's braking, in the manner of conventional thrust reversers, and each has a pitch angle of approximately 5° relative to the plane of rotation of the blades. In the extreme feathering position, the blades 5 are then as far removed as possible from the aircraft's forward direction, for example, in the event of a turbomachine failure, which helps to limit drag. In this latter position, the blade pitch angle is positive and is generally around 90° relative to the plane of rotation of the blades.

[0046] The pitch change system 15 includes a linkage mechanism 16 connected to the variable pitch vanes 2 and a control means 17 acting on the linkage mechanism 16.

[0047] The linkage mechanism 16 may include connecting rods, rods and / or levers.

[0048] Advantageously, but not exclusively, the control means 17 is hydraulic.

[0049] The control means 17 comprises a moving body and a fixed body (not shown) relative to the moving body. The fixed body is advantageously integral with the fixed structure of the turbomachine. As for the moving body, it moves axially in translation relative to the fixed body. The latter is mounted on a fixed housing so as to be immobile in translation and rotation relative to the fixed housing. According to another embodiment, the fixed body may be integral with the propeller shaft 8

[0050] In the present example, the control means 17 is a hydraulic cylinder comprising the fixed body and the moving body. The moving body is here the rod of the cylinder and the fixed body is here the cylinder of the cylinder, or vice versa.

[0051] The control means 17 is connected to a fluidic supply source 18 to supply pressurized fluid to chambers (not shown) of the control means 17. Advantageously, the fixed body comprises a radial wall that delimits the two variable-volume chambers in the moving body. The chambers are advantageously axially opposed. The moving body is mounted around the fixed body and coaxial with the longitudinal axis. Alternatively, the fixed body is mounted outside the moving body.

[0052] The moving body moves under the action of a control from the pitch change system 15. For this purpose, the pitch change system 15 is connected to a fluid supply system 19, for example hydraulic pressure.

[0053] More specifically, the supply system 19 includes the pressurized fluid supply source 18, which supplies the chambers of the control means 17. The supply source 18 is arranged, for example, in the nacelle of the turbine. The supply source 18 may be a main tank 20 that stores the supply fluid.

[0054] The power supply system 19 includes a main circuit 21 which is intended to supply at least the hydraulic control means 17.

[0055] The main circuit 21 includes a main supply pump 22 which is connected to the supply source 18. The main supply pump 22 allows the circulation of the fluid from the supply source (here the reservoir 20 as shown in [Fig.2]) to the control means 17. We understand that the main supply pump 22 is dedicated to the control of the propeller.

[0056] In this embodiment, the main feed pump 22 is driven downstream of the speed reducer 9. For this purpose, the main feed pump 22 uses the rotational speed of the power shaft 7 which is greater than that of the propeller shaft 8.

[0057] The main circuit 21 advantageously includes a pipe 23 that directly connects the main feed pump 22 by means of a control means 17. This pipe 23 is advantageously a high-pressure pipe. The pressure flowing in the pipe 23 is between 30 and 150 bar.

[0058] As shown schematically in [Fig.2], the pipe 23 passes through the speed reducer 9. The high-pressure fluid passes inside the propeller shaft.

[0059] Advantageously, but not exclusively, the pressurized fluid is oil.

[0060] The main feed pump 22 communicates with an electronic control unit 24, which is dedicated to controlling certain components and / or equipment of the turbomachine. This electronic control unit 24 may be an EEC (Electronic Engine Controller). The ECU is controlled by a full authority electronic system (known as FADEC for "Full Authority Digital Engine Control"), which manages the proper operation of the turbomachine. The ECU is also connected to means for monitoring power shaft parameters, such as its speed, and to means for detecting the fluid pressure in the main circuit.

[0061] A secondary feed pump 25 is also provided, which is driven by the power shaft 7. This secondary pump 25 is advantageously dedicated, but not limited to, the lubrication of other components and / or equipment of the turbine. The secondary feed pump 25 is arranged outside the enclosure 10. This frees up space in the lubrication enclosure 10.

[0062] Advantageously, but not exclusively, the main supply pump 22 is common to the lubrication of components and / or equipment of the turbomachine and the speed reducer 9 and allows an initial rise in the pressure level in the main circuit 21. For propeller actuation requirements, the required pressure level is achieved using the secondary supply pump 25.

[0063] In the present example, a connecting pipe 26 directly links the secondary pump 25 to the main supply pump 22. The secondary supply pump 25 is separate and independent from the main supply pump 22.

[0064] When the turbomachine 1 is running and all equipment and / or components are functional, the supply system 19 allows the circulation of pressurized fluid in the main circuit 21 to the control means 17 to change the pitch of the variable-pitch blades 2 to the different positions required according to the operating conditions. The fluid flows via the pipes 23, 26 and the supply pump 22. The supply pump 22 is primed (or activated) as soon as the power shaft 7 rotates at a predetermined speed and / or a predetermined pressure P is reached in the main circuit 21 so as to allow the circulation of fluid from the supply source 18 to the chambers of the control means 17. This mode of operation takes place after the turbomachine has started and during flight.

[0065] The supply system 19 includes a hydraulic accumulator 27 which is intended to supply the control means 17 when the supply pump 22 is inactive (for example in the event of failure of the pump 22 or if the power shaft 7 no longer rotates) to drive the variable pitch vanes 2 into the feathering position.

[0066] The hydraulic accumulator 27 is configured to store hydraulic fluid. The hydraulic accumulator 27 is also configured to maintain the hydraulic fluid under pressure. The pressure that can exist in the hydraulic accumulator is between 30 and 150 bar.

[0067] The supply system 19 includes an auxiliary circuit 28 which includes the hydraulic accumulator 27. The auxiliary circuit 28 is advantageously independent of the main circuit 21.

[0068] The auxiliary circuit 28 includes an auxiliary pipe 29 directly connecting the hydraulic accumulator 27 to the pipe 23.

[0069] Advantageously, but not exclusively, the hydraulic accumulator 27 is installed outside the lubrication chamber 10. This also frees up space inside the lubrication chamber and facilitates maintenance. In this example, the accumulator 27 is fixed to the annular housing 11 surrounding the speed reducer 9.

[0070] The hydraulic accumulator 27 is associated with a control device 30 that is configured to occupy at least one closed position and one open position. In the closed position, the control device 30 blocks the flow of hydraulic fluid from the hydraulic accumulator 27 to the control means 17. In the open position, the control device 30 allows the flow of hydraulic fluid from the hydraulic accumulator 27 to the control means 17. In other words, the control device 30 is mounted in a sealed manner at an outlet port 31 of the hydraulic accumulator 27. The control device 30 is advantageously configured to open or close the outlet port 31.

[0071] The hydraulic accumulator 27 comprises a peripheral wall 32 delimiting a volume 33 receiving the hydraulic fluid. The peripheral wall 32 includes the outlet 31 through which the fluid can fill the volume or empty the volume into the auxiliary pipe 29. The outlet 31 is connected to the auxiliary pipe 29.

[0072] The storage volume 33 can be equivalent to the volume defined by the displacement (here, a translation) of the moving body of the control means 17 when the latter moves from the "full fine pitch" position (pitch angle at 0°) to the feathered position (pitch angle at 90°). The full fine pitch position corresponds to a takeoff phase of the aircraft (vertical forward speed only). The blade pitch angle in the thrust reversal position can be as low as -10°. The accumulator 17 must contain enough hydraulic fluid to cause this translation of the control means 17.

[0073] According to one embodiment, the hydraulic accumulator 17 includes means 36 for pressurizing the volume 33 or the hydraulic fluid. The volume 33 is divided into two chambers (not shown and referred to as the first chamber and the second chamber) by a sealed element (not shown) and includes two orifices. Each first and second chamber is coupled to an orifice. The first chamber is connected to the main circuit 19, and the second chamber is filled with a pressurized inert gas such as nitrogen. Advantageously, the first chamber is connected to the main circuit 19 via the outlet orifice 31. The inert gas creates a counterforce (equivalent to a mechanical spring). This configuration maintains the hydraulic fluid under pressure in the hydraulic accumulator.

[0074] According to one embodiment, the volume 33 is filled with the hydraulic fluid prior to the installation of the accumulator 27 in the turbomachine.

[0075] Advantageously, but not limitingly, the hydraulic fluid stored in the accumulator 27 is identical to the fluid circulating at least in the pipe 21.

[0076] Advantageously, the regulating device 30 is arranged between the outlet port 31 and the auxiliary pipe 29.

[0077] Advantageously, the control device 30 is a non-return valve 34. This is simple to implement and install in the auxiliary circuit 28. On the other hand, it is a lightweight component which does not affect the mass of the turbomachine.

[0078] The non-return valve 34 can be integrated into the hydraulic accumulator 27.

[0079] Alternatively, the regulating device 30 may comprise a valve, a drawer device as soon as these can be ordered to release the outlet orifice 31.

[0080] The non-return valve 34 is mounted at the outlet orifice 31 so as to block or release the outlet orifice 31.

[0081] For this purpose, the check valve 34 comprises a passage 34a and a sealing element 34b which is movably mounted inside this passage. The passage is fluidly connected to the auxiliary pipeline. The sealing element 34c is intended to open or close the passage. The passage is advantageously delimited by a conical wall 34c, the apex of which forms a seat. The check valve 34 further comprises a spring 34d which holds the sealing element in the closed position against the seat. In the present embodiment, the sealing element 34b comprises a ball.

[0082] Alternatively, the sealing element 34b comprises a stem extending from a base. The passage 34a in this case has a shape conforming to the shape of the stem and the base for a tight seal.

[0083] In the present example, the non-return valve 34 is electrically controlled. Advantageously, but not exclusively, the non-return valve 34 is connected to the control unit which controls its opening and closing.

[0084] In particular, the check valve 34 changes position when the pressure in the auxiliary line 39 reaches a predetermined value. Advantageously, the valve 34 opens when the predetermined value is less than the pressure flowing in the line 23, and the valve 34 closes when the predetermined value is greater than the predetermined value. The pressure decreases in the line 23 in the event of a failure of the main pump 22, the turbomachine 1, etc. Conversely, the pressure increases in the main circuit 19 when the main supply pump 22 is active, which prevents the fluid from the hydraulic accumulator 27 from flowing to the control means 17.

[0085] Once the outlet 31 of the hydraulic accumulator 27 is opened, the pressurized fluid flows into the auxiliary pipe 29 and then into a part from the pipeline 23 to the control means 17. The pressure increases in the auxiliary circuit 28 until it reaches a pressure which will cause the moving body of the control means 17 to move so that the blades 2 occupy the feathering position.

[0086] Thus, the hydraulic accumulator 27 operates completely autonomously to compensate for the failure of the main feed pump 22 and to feather the variable-pitch blades. Furthermore, the arrangement of this hydraulic accumulator 27 does not entail any major modifications to the lubrication chamber 10 and / or the gearbox housing.

[0087] Advantageously, the supply system 19 includes a recovery pipeline 35 which directly connects the control means 17 to the main reservoir 20.

Claims

Demands

1. Turbomachine module comprising: - a plurality of variable-pitch blades (2), - a power shaft (7) driving the variable-pitch blades (2) via a speed reducer (9), - a pitch change system (15) comprising a linkage mechanism (16) connected to the variable-pitch blades (2) and a hydraulic control means (17) acting on the linkage mechanism (16); and - a pressurized fluid supply system (19) comprising a main circuit (21) for supplying the hydraulic control means (17), the main circuit (21) comprising a main supply pump (22) which is connected to a power source (18) and which is driven by the power shaft (7), and a hydraulic accumulator (27) configured to store a hydraulic fluid, the hydraulic accumulator (27) being on the one hand connected to the main circuit (21) and on the other hand intended to supply the control means (27) when the main supply pump (22) is inactive so as to drive the variable pitch vanes (2) into the feathering position, characterized in that the hydraulic accumulator (27) is installed outside a lubrication enclosure (10) in which the speed reducer (9) is arranged.

2. Module according to the preceding claim, characterized in that the hydraulic accumulator (27) is associated with a regulating device (30) which is configured to occupy at least: - a closed position in which the regulating device (30) blocks the passage of hydraulic fluid from the hydraulic accumulator (27) to the control means (17); and - an open position in which the regulating device (30) allows the passage of hydraulic fluid from the hydraulic accumulator (27) to the control means (17).

3. Module according to the preceding claim, characterized in that the regulating device (30) occupies the open position when the pressure decreases in the main circuit (21) to reach a predetermined value.

4. Module according to any one of the preceding claims, characterized in that the main circuit (21) comprises a pipe (23) directly connecting the control means (17) to the main supply pump (22) and in that an auxiliary pipe (29) directly connects the hydraulic accumulator (27) to the pipe (23).

5. Module according to the preceding claim, characterized in that the control device (30) comprises a check valve (34) arranged between an outlet port (31) of the hydraulic accumulator (27) and the auxiliary pipeline (29).

6. Module according to any one of the preceding claims, characterized in that the conduit (23) passes through the speed reducer (9).

7. Module according to any one of the preceding claims, characterized in that the hydraulic fluid stored in the hydraulic accumulator (27) is identical to the fluid circulating at least in the main circuit (19).

8. Module according to any one of the preceding claims, characterized in that the accumulator (27) includes means for pressurizing the hydraulic fluid.

9. Aircraft turbomachine (1) comprising a turbomachine module according to any one of the preceding claims.

10. Aircraft comprising a turbomachine according to the preceding claim.

Images