Turbomachine module equipped with a blade pitch change system of stator vanes

Abstract

The invention relates to a turbomachine module having a longitudinal axis X, comprising an unducted propeller (2) rotating about the longitudinal axis X and at least one straightener (25) comprising a plurality of unducted variable-pitch stator vanes (26) extending from a fixed casing along a radial axis Z perpendicular to the longitudinal axis X. According to the invention, the module comprises a pitch change system (30) of the first stator vanes (26) comprising: • - at least one first control device (31) comprising a first fixed body (75) connected to the fixed casing and a first mobile body (76) axially mobile relative to the first fixed body, • - at least one first engagement mechanism (32) engaging each stator vane (26) to the first mobile body (76) of the first control device (31), the first engagement mechanism (32) comprising: • o an engagement ring (30) centred on the longitudinal axis and engaged to a foot (28) of each stator vane, and • o at least one rod (73) connected on one hand to the engagement ring (60) and on the other hand to the first mobile body (76) of the first control device.

Description

Technical Field

[0001] This invention relates to the field of turbines, and more particularly to a turbine module comprising a ductless propeller. The invention is also applicable to corresponding turbines. Background Technology

[0002] A turbine that includes at least one ductless propeller is called an "open rotor" or "ductless fan." In such turbines, there are two ductless propellers rotating in opposite directions (called an Unducted Dual Fan (UDF)) or a single ductless propeller and a straightener comprising multiple stator blades (called an Unducted Single Fan (USF)). One or more propellers forming the propulsion section can be positioned behind the gas generator (or engine) so that the gas generator is push-type, or positioned in front of the gas generator so that the gas generator is pull-type. These turbines are turboprop engines, which differ from turbojet engines in that they use an external (ductless) propeller instead of an internal fan. This allows for a very significant increase in bypass ratio, unaffected by the mass of the casing or nacelle designed to surround the propeller or fan blades. Examples of turboprop engines are described in documents FR-A1-3082230 and US-A1-2017 / 102006.

[0003] In the case of a turbine with a single ductless propeller and a straightener, the straightener can be of variable pitch type to improve turbine performance, particularly from an aerodynamic perspective. The straightener blades are oriented according to the needs and phases of flight (takeoff, cruise, landing, etc.). However, depending on the turbine architecture, the integration of the device that makes the straightener blades pitched presents a problem in terms of mass, drag, volume, and the complexity of these devices. Summary of the Invention

[0004] The purpose of this invention is to provide a turbine module having a system for changing the pitch of the blades of a straightener, which is easy to integrate and avoids major structural modifications.

[0005] According to the invention, this is achieved by a turbine module having a longitudinal axis X, the turbine module comprising a ductless propeller rotatably driven about the longitudinal axis and at least one straightener, the at least one straightener comprising a plurality of ductless variable-pitch stator blades extending from a fixed housing along a radial axis perpendicular to the longitudinal axis, the module comprising a first system for changing the pitch of the stator blades, the first system comprising:

[0006] - At least one first control device, the at least one first control device comprising a first fixed body connected to a fixed housing and a first movable body axially movable relative to the first fixed body.

[0007] - At least one first connecting mechanism, which connects each stator blade to a first movable body of the first control device, the first connecting mechanism comprising:

[0008] ○ Connecting ring, the connecting ring is centered on the longitudinal axis and is connected to the root of each stator blade, and

[0009] ○ At least one rod, which is connected on one side to a connecting ring and on the other side to the first movable body of the first control device.

[0010] Therefore, this solution enables the achievement of the aforementioned objectives. In particular, this configuration is easy to implement and simplifies the kinematics of stator blade pitch change. In fact, in the first connection mechanism, all blades change their orientation simultaneously without involving many components that could affect mass and complicate the kinematics.

[0011] The module also includes one or more of the following features, which may be used individually or in combination:

[0012] - The first connecting mechanism includes multiple arms, each of which is connected to the stator blades and the connecting ring.

[0013] - Each arm includes a first end and a second end. The first end is provided with a spherical joint connection part through which a first hinge shaft carried by a connecting ring passes. The second end is connected to the root of the stator blade in an embedded connection manner.

[0014] The rod is held by a support member, which is fixed to a fixed housing, and the rod is pivotally connected to the support member.

[0015] The rod has an L-shape and has a first branch and a second branch. The first branch and the second branch each include a first distal end and a second distal end. The first distal end of the first branch is pivotally connected to the axial rod of the first movable body of the first control device. The second distal end of the second branch includes a ball joint through which a second hinge shaft carried by a connecting ring passes.

[0016] - The first pitch changing system includes two first control devices and two levers, which are respectively connected to the first control devices and the connecting ring.

[0017] - The first pitch-changing system is installed in the annular space of the outer casing, which partially defines the main duct through which the main airflow passes.

[0018] - The outer casing supports the separator nose, and the first control device is arranged at the level of the separator nose.

[0019] - The stator blades are configured to pivot between -10° and +10°.

[0020] - The connecting ring is unique.

[0021] - The first hinge axis of the arm is regularly arranged around the longitudinal axis X.

[0022] - The module includes a second system for changing the pitch of the movable blades of the propeller, the second system comprising:

[0023] ○ The second control device includes a second movable body that is axially movable relative to a second fixed body mounted on the inner housing, and movable blades are mounted on a rotating housing supported by the inner housing.

[0024] ○ At least one load-transfer bearing, the at least one load-transfer bearing comprising an outer ring and an inner ring connected to a second movable body; and

[0025] ○ Second mechanism, used to connect the outer ring to the propeller blades.

[0026] - The inner and outer shells at least partially define the main duct through which the main airflow passes.

[0027] The present invention also relates to an aircraft turbine comprising at least one module as described above and a gas generator for driving the rotation of a ductless propeller. Attached Figure Description

[0028] The invention will be better understood by reading the following detailed illustrative description of embodiments of the invention, given as purely illustrative and non-limiting examples, with reference to the illustrative drawings, in which:

[0029] [ Figure 1 ] Figure 1 This is a schematic diagram of the axial and partial cross-section of an example turbine with a single ductless propeller to which the present invention applies;

[0030] [ Figure 2 ] Figure 2 A perspective view is shown of a system for changing the blade pitch of the stator blades of a turbine with a single ductless propeller to which the present invention is applicable.

[0031] [ Figure 3 ] Figure 3This is a partial axial cross-sectional view of the stator blade root of the turbine according to the present invention;

[0032] [ Figure 4 ] Figure 4 This is a partial perspective view of the stator blade pitch changing system of a turbine with a single ductless propeller according to the present invention.

[0033] [ Figure 5 ] Figure 5 This is an axial cross-sectional view of the rod of the connecting mechanism that is connected to the rod of the movable body of the control device according to the present invention;

[0034] [ Figure 6 ] Figure 6 This is an axial cross-sectional view of the rod of the connecting mechanism that connects to the support member and the connecting ring member according to the present invention;

[0035] [ Figure 7 ] Figure 7 An example of a system for changing the pitch of stator blades is shown in the perspective view and upstream view, the system being arranged in the fixed housing of a turbine according to the invention. Detailed Implementation

[0036] This invention applies to a turbine 1, which includes a ductless propeller 2 for mounting on an aircraft. Such a turbine is as follows: Figure 1 The turboprop engine shown is described above. The turbine is referred to as an "open rotor" or "ductless fan."

[0037] In this invention, and generally, the terms "upstream," "downstream," "axial," and "axially" refer to the gas flow in the turbine and here along the longitudinal axis X (even in...). Figure 1 The terms "radial," "inner," and "outer" are defined relative to the radial axis Z perpendicular to the longitudinal axis X and relative to the distance from the longitudinal axis X. Furthermore, identical or substantially identical elements and / or elements having the same function are indicated by the same reference numerals.

[0038] Turbine 1 includes a gas generator or engine 3, which, from upstream to downstream, comprises a low-pressure compressor 4, a high-pressure compressor 5, a combustion chamber 6, a high-pressure turbine 7, and a low-pressure turbine 8. The low-pressure compressor 4 and the low-pressure turbine 8 are mechanically connected via a low-pressure shaft 9 to form a low-pressure body. The high-pressure compressor 5 and the high-pressure turbine 7 are mechanically connected via a high-pressure shaft 9 to form a high-pressure body. The high-pressure shaft extends inside the low-pressure shaft 9, and the high-pressure shaft and the low-pressure shaft are coaxial.

[0039] In another configuration, not shown, the low-pressure unit includes a low-pressure compressor connected to the intermediate-pressure turbine. A free-powered turbine is mounted downstream of the intermediate-pressure turbine and connected via a power drive shaft to a propeller, as described below, to drive the propeller to rotate.

[0040] The main airflow F1 flows through the main duct 10 passing through the gas generator 3. The main duct 10 is radially defined by a radial inner wall 11 and a radial outer wall 12. The radial inner wall 11 is supported by an inner housing 13. The radial outer wall 12 is supported by an outer housing 14. The main airflow F1 enters the gas generator 3 through an annular air inlet 15 and exits through a main nozzle 16 located downstream of the gas generator 3.

[0041] The turbine includes a rotating housing 20 that centers on and rotates about a longitudinal axis X. The rotating housing 20 carries an annular gear that forms movable blades 21 of the propeller 2. The rotating housing 20 is mounted such that it is movable relative to an inner housing 13 that supports it. Figure 1 In the example shown, propeller 2 is mounted upstream of the gas generator (traction configuration). Alternatively, propeller 2 is mounted downstream of the gas generator (push configuration). Airflow F entering the turbine passes through propeller blades 21 to form a secondary airflow F2. This secondary airflow flows around the outer casing 14. Airflow F is split into a primary airflow and a secondary airflow at the level of the separator nose 22 carried by the outer casing 14. Each blade 21 of propeller 2 includes a root 23 and extends radially outward from the root 23. Figure 1 As shown, the propeller blades are without ducts (the turbine shown is of the "USF" type, i.e., as described above, the turbine consists of a single ductless propeller and a straightener, which consists of multiple ductless stator blades).

[0042] The power shaft or low-pressure shaft 9 (a power shaft or low-pressure shaft with a free-running turbine and a low-pressure turbine respectively) drives the propeller 2 through a reduction gear 24, which compresses the air outside the outer casing 14 and provides most of the thrust. The reduction gear 24 can be of the planetary gear type or the planetary gear type.

[0043] like Figure 1 As shown, the turbine 1 includes a straightener 25 comprising a plurality of stator blades 26 (or fixed blades), known as outlet guide vanes (OGVs). The stator blades 26 are uniformly distributed around a longitudinal axis X and extend radially into the secondary airflow. The stator blades 26 are supported by a fixed structure attached to the outer housing 14. Specifically, each stator blade 26 includes a blade 27 extending radially from a root 28. It is understood that the stator blades 26 are ductless.

[0044] exist Figure 2 In this turbine, ten stator blades 26 are mounted on the outer casing 14. Advantageously, the pitch of the stator blades 26 is variable to optimize turbine performance. For this purpose, the turbine includes a first system 30 for changing the pitch of the stator blades. Figure 2 In the first pitch changing system 30, there are at least one first control device 31 and at least one first connection mechanism 32 that connects each stator blade 26 to the first control device 31.

[0045] Figure 3 An axial cross-sectional view of the root 28 of the stator blade 26 is shown. Typically, the root 28 takes the form of a pivot 33, which is pivotally mounted in a housing 34 along axis A. Specifically, an annular shroud 35 centered on the longitudinal axis X includes a plurality of housings 34 circumferentially distributed around the annular shroud. The annular shroud 35 is secured to the outer housing 14. Each housing 34 is defined by a cylindrical skirt-like portion 36 extending along the radial axis Z. The pivot 33 of the root is pivotally mounted by at least one guide bearing 37. In this example, two guide bearings 37, 37' are stacked along the radial axis Z. These bearings 37 are preferably, but not limited to, rolling bearings.

[0046] Each bearing 37, 37' includes an inner ring 38 rotatably fixed to a pivot 33 and an outer ring 39 surrounding the inner ring 38. A rolling element is mounted between the inner surface of the inner ring 38 and the inner surface of the outer ring 39, forming a track. Here, the rolling element includes a spherical portion 40.

[0047] Cylindrical sleeves 41 are installed in each receiving portion 34 to connect the inner ring 38 of each bearing 37, 37' to the root of each stator blade 26. Sleeves 41 are centered on the pitch axis A of the stator blade. Each sleeve 41 extends between a first end 42 and a second end 43. Each sleeve 41 has an inner spline 44 arranged on an inner cylindrical surface. The inner spline 44 is intended to engage with an outer spline 45, which is provided on the outer surface of the pivot 33 at the root of each stator blade 26. The second end 43 of the sleeve 41 includes a collar 46 extending radially outward from the (cylindrical) body of the sleeve 41 relative to axis A. The collar 46 forms a radially outer surface 47 on which the hub 48 of the pivot 33 rests. The outer ring 39 of each bearing 37, 37' is supported by a shroud 35, specifically by a cylindrical skirt 36. The spacer 50, extending along the radial axis Z between each bearing, is intended to maintain a distance (in this case, a radial distance) between the two bearings 37, 37'. The spacer 50 is advantageously, but not limitingly, arranged between the two inner rings 38 of the bearings 37, 37'.

[0048] The shield 35 also includes an annular bottom wall 51 fixed to the cylindrical skirt portion 36. The bottom wall includes a hole 53 that passes through the bottom wall on both sides along the radial axis and allows the free end 54 of the pivot 33 to pass through.

[0049] Sealing elements are arranged in each housing 34 to prevent lubricant from leaking from the bearing to the outside of the housing. Specifically, a first annular seal 55 is arranged between the inner surface 56 of the cylindrical skirt-shaped portion 36 and the outer peripheral boundary 48a of the hub portion 48. A second seal 57 is provided between the inner boundary 58 of the hole 53 and the outer surface 41a of the sleeve 41.

[0050] Finally, to prevent any displacement of the pivot 33 along the radial axis, the retaining element 59 allows the free end 54 of the pivot to be attached to the bottom wall 51 of the housing 35. The retaining element 59 includes a nut. Of course, other similar threaded elements that allow the pivot to be attached to the housing are also possible.

[0051] Reference Figure 3 and Figure 4 The first connecting mechanism 32 includes a connecting ring 60 centered on the longitudinal axis X. The connecting ring 60 includes a first annular segment 61 and a second annular segment 62 that are concentric and coaxial. The first segment 61 and the second segment 62 are radially spaced apart and connected to each other by a bridging member 63 forming a through hole 64 along the longitudinal axis. The connecting ring 60 is connected to the root of each stator blade.

[0052] For this purpose, the first connecting mechanism 32 includes at least one arm 65, which is connected on one side to the connecting ring 60 and on the other side to the root 28 of the impeller 26. The arm 65 extends between a first end 66 and a second end 67. The first end 66 is provided with a ball joint 68 (see...). Figure 3 The spherical joint is traversed by a hinge shaft 69 carried by a connecting ring 60. The hinge shaft 69 is mounted between the first section 61 and the second section 62, and is parallel to the radial axis Z. The second end 67 is connected to the root 28 of the stator blade 26 in an embedded connection. Figure 3 As shown, the second end 67 includes an aperture 70 that passes through the second segment on both sides along a radial axis. The free end 54 of each pivot is fitted into each aperture 70. Advantageously, but not limitingly, the pivot 33 includes a radial bore 71 that opens at the level of its free end 54. An attachment member 72, such as a screw, is received in the radial bore 71 to attach an arm 65 to the root of the stator blade 26. In the example shown, the number of arms is as many as the number of stator blades. Each arm is connected to the blade root and the connecting ring 60.

[0053] Reference Figure 4 and Figure 5 The first connecting mechanism 32 also includes at least one rod 73, which is connected to the connecting ring 60 on one side and to the first control device 31 on the other side.

[0054] In this example, there are two first control devices 31 and two levers 73 that cooperate with each other. The two first control devices 31 enable the transmission of force to the connecting ring 60 and allow the pitch of the stator blades 26 to be changed. The first connecting devices are radially opposite to the axis of the connecting ring 60.

[0055] Each first control device 31 includes a first fixed body 75 and a first movable body 76 movable relative to the first fixed body. Each first fixed body 75 is connected to a turbine mounting cover 77 (see [link]). Figure 5 The first movable body 76 is designed to be immovable during translation and rotation. Specifically, the fixed cover 77 is mounted on the outer housing 14. Each first movable body 76 is translatably displaced relative to the corresponding first fixed body 75 along the longitudinal axis X. Each first movable body 76 includes an axial rod 78, the free end 79 of which is connected to a rod 73.

[0056] Each rod 73 is L-shaped, having a first branch 80 and a second branch 81 connected to each other. Figure 5 In the middle, the first branch 80 is at the first distal end 82 (see...) Figure 4 The location includes a U-shaped clip 83. According to... Figure 5 The U-shaped clamp includes a first ear 84 and a second ear 85 stacked and spaced along a radial axis. The first ear 84 and the second ear 85 extend in a plane that is generally parallel to each other. A hinge shaft 86 extends along an axis parallel to the radial axis between the first ear and the second ear. The free end 79 of the axial bar 78 includes an eyelet through which the hinge shaft 86 passes for pivoting connection.

[0057] exist Figure 6 In the second branch 81, a ball joint 87 is included, through which a second hinge shaft, carried by a connecting ring 60, passes. The second hinge shaft is mounted between the first section 61 and the second section 62, and is parallel to the radial axis Z.

[0058] Reference Figure 6 Rod 73 is mounted on support 90, which is fixed to the turbine's mounting structure. The mounting structure is fixed to the outer housing 14. Support 90 allows rod 73 to be held relative to the outer housing 14. Specifically, at the level of the joint between the first branch 80 and the second branch 81, rod 73 is pivotally connected to support 90. Figure 4As shown, the support includes a base plate 91 connected to a body 92. The body is attached to a fixing structure 93, which is fixed to the outer casing of the turbine. This attachment is accomplished by attachment members such as screws and nuts. The base plate 91 extends in a plane perpendicular to the radial axis and parallel to the plane defining the body. The base plate 91 and the body 92 form a C-shape or a U-shape. The space between the base plate 91 and the body 92 receives the apex 94 of the rod 73 defined by the junction of the first branch and the second branch. The apex 94 passes through an aperture 95 along the radial axis. A pivot member 96, carried by the body and the base plate 91, extends along the radial axis Z through the aperture of the rod. An upper buffer pad 97 and a lower buffer pad 98 are arranged in the aperture 95. The pivot member passes through the buffer pads 97 and 98.

[0059] Then, each rod 73 has three axes of rotation.

[0060] Advantageously, each of the first control devices is a hydraulic cylinder comprising a fixed body and a movable body. Each first control device is connected to a fluid supply source for supplying pressurized oil to a chamber (not shown) of the fixed body. The movable body extends inside the fixed body.

[0061] Advantageously, the pitch-changing system is arranged in an annular space 29 defined within the outer housing 14. For example... Figure 1 As shown, each first control device is arranged at the level of the separator nose 22. In particular, each first control device is arranged upstream of the root 28 of the stator blades and also upstream of the connecting annulus 60.

[0062] The axial rod 78 of each movable body extends through the through hole 64 defined in the connecting ring 60.

[0063] We will now describe the kinematics of the individual components during the pitch change of the stator blades. All blades of stator blade 26 pivot simultaneously. As the first movable body 76 of the first control device 31 translates along the longitudinal axis, the free end 79 of the axial rod 78 of the first movable body 76 also translates along the axis X, driving the rotation of the rod 73 connected to the support. This rod 73, also connected to the connecting ring 60, drives the connecting ring 60 to rotate about the longitudinal axis, resulting in a pitch change of the stator blades 26 connected to the connecting ring 60 via the arm 65. In this way, with the translation of the first movable body of the cylinder and the rotation of the rod 73 connected to the individual connecting ring 60, all blades of stator blade 26 change their blade pitch or blade orientation. The blades of stator blade 26 rotate between -10° and +10°.

[0064] The turbine module may include a second system 100 for changing the pitch of the movable blades of the propeller 2. This second pitch-changing system is arranged upstream of the gas generator 3 and radially below the root of the movable blade 21 of the propeller 2. The pitch-changing system 100 includes a second control device comprising a second movable body axially movable relative to a second fixed body mounted on the inner housing 13. The pitch-changing system also includes at least one load-transfer bearing and a second mechanism comprising an outer ring and an inner ring connected to the second movable body, the second mechanism for connecting the outer ring to the movable blade of the propeller. The system for changing the pitch of the blades of the propeller 2 enables the change of the pitch of the blade 21 about its pitch axis, such that the blade occupies different angular positions depending on the turbine operating conditions and the relevant flight phase (e.g., extreme operating positions of the blade (thrust reversal position) and extreme feathering positions). The second control device is also a hydraulic cylinder comprising the second fixed body and the second movable body. Here, the connecting mechanism includes a connecting rod.

Claims

1. A turbine module having a longitudinal axis (X), the turbine module comprising a ductless propeller (2) rotated about the longitudinal axis (X) and at least one straightener (25), the at least one straightener comprising a plurality of ductless variable-pitch stator blades (26) extending from a fixed housing along a radial axis (Z) perpendicular to the longitudinal axis (X), and the turbine module comprising a first pitch changing system (30) for changing the pitch of the blades of the stator blades (26), the first pitch changing system comprising: At least one first control device (31) includes a first fixed body (75) connected to the fixed housing and a first movable body (76) axially movable relative to the first fixed body (75). At least one first connecting mechanism (32) connects each stator blade (26) to the first movable body (76) of the first control device (31), the first connecting mechanism (32) comprising: A connecting ring (60), centered on the longitudinal axis, is connected to the root (28) of each stator blade, and At least one rod (73) is connected on one side to the connecting ring (60) and on the other side to the first movable body (76) of the first control device (31). The rod (73) is characterized in that it is L-shaped and has a first branch (80) and a second branch (81), the first branch and the second branch respectively including a first distal end and a second distal end, the first distal end of the first branch (80) being pivotally connected to the axial rod (78) of the first movable body (76) of the first control device (31), and the second distal end of the second branch (81) including a ball joint (87), the ball joint being supported by a second hinge shaft (88) carried by the connecting ring (60). 8) Through which the second hinge axis is parallel to the radial axis (Z), the axial bar (78) of the first movable body (76) passes through a through hole (64) defined in the connecting ring (60) along the longitudinal axis (X), the through hole (64) being formed by a bridge (63) connecting the first annular segment (61) and the second annular segment (62) of the connecting ring (60) to each other, the first annular segment (61) and the second annular segment (62) being concentric, coaxial and radially spaced.

2. The turbine module according to claim 1, characterized in that, The first connecting mechanism (32) includes a plurality of arms (65), each of which is connected to the stator blade (26) and the connecting ring (60).

3. The turbine module according to claim 2, characterized in that, Each arm (65) includes a first end and a second end, the first end being provided with a ball joint connection (68) through which a first hinge shaft (69) carried by the connecting ring (60) passes, and the second end being connected to the root (28) of the stator blade (26) by an embedded connection.

4. The turbine module according to any one of claims 1 to 3, characterized in that, The rod (73) is held by a support (90) which is fixed to the fixed housing, and the rod is pivotally connected to the support (90).

5. The turbine module according to any one of claims 1 to 3, characterized in that, The first pitch changing system (30) includes two first control devices (31) and two rods (73), the two rods being respectively connected to the first control devices (31) and the connecting ring (60).

6. The turbine module according to any one of claims 1 to 3, characterized in that, The first pitch changing system (30) is installed in the annular space (29) of the outer housing (14), which partially defines the main duct (10) through which the main airflow passes.

7. The turbine module according to claim 6, characterized in that, The outer housing (14) carries the separator nose (22), and the first control device (31) is arranged at the level of the separator nose (22).

8. The turbine module according to any one of claims 1 to 3, characterized in that, The stator blades (26) are configured to pivot between -10° and +10°.

9. The turbine module according to any one of claims 1 to 3, characterized in that, The connecting ring (60) is unique.

10. The turbine module according to any one of claims 1 to 3, characterized in that, The turbine module includes a second pitch changing system (100) for changing the pitch of the movable blades (21) of the ductless propeller (2), the second pitch changing system including: The second control device includes a second movable body axially movable relative to a second fixed body mounted on the inner housing (13), the movable blade (21) being mounted on a rotating housing (20) carried by the inner housing (13). At least one load-transfer bearing, the at least one load-transfer bearing comprising an outer ring and an inner ring connected to the second movable body; and A second mechanism is used to connect the outer ring to the movable blade of the ductless propeller.

11. The turbine module according to claim 10, characterized in that, The inner shell (13) and the outer shell (14) at least partially define the main duct (10) through which the main airflow passes.

12. An aircraft turbine (1) comprising at least one turbine module according to any one of claims 1 to 11 and a gas generator (3) for driving the rotation of the ductless propeller (2).

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