Propulsion system for aircraft and aircraft comprising such propulsion system

Abstract

The invention relates to a propulsion system (1) for an aircraft and to an aircraft having such a propulsion system (1). The invention relates to a propulsion system (1) having a longitudinal axis (A1) and comprising: a propeller (2) movable in rotation about the longitudinal axis (A1) and comprising a plurality of blades (20) distributed at an angle with respect to said longitudinal axis, and first means (3) for adjusting the blade angle of said blades, the first device (3) is configured to adjust the blade angle of each blade according to the angular position of each blade about the longitudinal axis. The propulsion system can cyclically adjust the blade angle of each blade according to the angular position of each blade. This adjustment enables the adjustment of the blade angle of the blades during the complete rotation in order to produce optimal thrust regardless of the flight phase. In addition, this adjustment can reduce the effects of distortion of the flow, and thus greatly reduce noise.

Description

Technical Field

[0001] This invention relates to a propeller propulsion system for an aircraft, comprising means for adjusting the blade angle of the propeller blades. This adjustment allows the pitch of each blade of the propeller to be adjusted according to the position of the blades during propeller rotation. The invention also relates to an aircraft comprising at least one such propulsion system. Background Technology

[0002] In propeller propulsion systems used in aircraft, it is known to adjust the pitch of the propeller blades during different phases of flight. In fact, adjusting the propeller blade pitch allows for the adjustment of the propulsion system's thrust according to the different flight phases of the aircraft. For example, the blade pitch can be adjusted between the takeoff phase and the constant-speed flight phase (called the cruise phase).

[0003] For this purpose, propulsion systems typically include a system for controlling the pitch of the propeller blades of an aircraft, designed to uniformly adjust the blade angles of all blades. Thus, the same blade angle variation applies to all blades, regardless of their angular position relative to the longitudinal axis of the propulsion system around which the propeller rotates.

[0004] Currently, height distortion of the airflow entering the front of the propeller is observed during different flight phases. Although tilting the propulsion system to control the distortion of the airflow entering the front of the propeller is also known, this solution is only effective for a given flight condition, namely the cruise phase. Therefore, the solution of the prior art is not optimal for other flight phases of the aircraft, especially the takeoff phase.

[0005] In fact, during takeoff, the airflow entering the front of the propeller continues to distort. This results in an axisymmetric inflow to the propeller, and thus an axisymmetric load on each blade, which significantly impacts the aircraft's noise level and directivity. Specifically, the riser and descent blades do not experience the same local angle of attack and therefore do not generate the same loads. This load difference between the riser and descent blades leads to increased static loads at the aircraft level and increased vibration loads at the blade level.

[0006] In particular, on the ground, the descending blades generate a high level of noise.

[0007] Therefore, it is necessary to provide a solution for adjusting the blade angle of the propeller blades of the propulsion system used in aircraft, which can adjust the blade pitch of the propeller to optimize the load generated by each blade and limit the noise generated by the propeller. Summary of the Invention

[0008] The purpose of this invention is to provide a propeller propulsion system for aircraft that can optimally adjust the blade angle of the propeller blades.

[0009] To this end, a propulsion system for an aircraft is proposed, which has a longitudinal axis and includes:

[0010] - A propeller capable of rotational movement about the longitudinal axis, the propeller comprising a plurality of blades, each blade having a blade axis generally perpendicular to the longitudinal axis, the blades being distributed at an angle relative to the longitudinal axis; and

[0011] - A first device for adjusting the blade angle of the blades, the first adjusting device being configured to adjust the blade angle of each blade according to the angular position of each blade about the longitudinal axis.

[0012] This propulsion system can cyclically adjust the blade angle of each blade based on its angular position about the longitudinal axis (that is, repeatedly adjust it during each rotation of the propeller). This cyclic adjustment allows the blade angle to be adjusted during the propeller's complete rotation about the longitudinal axis, thus enabling the propeller to provide optimal thrust to the blades regardless of the flight phase of the aircraft. Furthermore, this adjustment of the blade angle based on the blade's angular position about the longitudinal axis allows different blade angles to be assigned to the ascending and descending blades, aiming to adjust the load applied to each blade of the propeller and thus reduce the distortion of the flow entering the front of the propeller during the takeoff phase. This significantly reduces the noise generated by the propeller during this flight phase.

[0013] In order to adjust the blade angle of each blade according to the angular position of each blade about the longitudinal axis, the first adjusting device advantageously includes a generally tubular roller that is generally coaxial with the longitudinal axis, the roller having a receiving portion on its outer surface configured to receive the root of the blade, the receiving portion extending along a first plane that is at a non-zero angle between -15° and +15° relative to a plane perpendicular to a reference plane containing the longitudinal axis.

[0014] In a first embodiment of the invention, the roller is fixed in rotation about the longitudinal axis, and the receiving portion takes the form of a groove that generally extends along the first plane, the root of the blade is received in the groove such that the blade pivots about the roller and about the longitudinal axis, and the angle of the first plane relative to the vertical plane is fixed, non-zero and between -15° and +15°.

[0015] In a second embodiment of the invention, the roller is fixed in rotation about the longitudinal axis, and the receiving portion takes the form of a groove that generally extends along the first plane, the root of the blade is received in the groove such that the blade pivots about the roller and about the longitudinal axis, and the first adjusting device is configured to adjust the angle of the first plane relative to the vertical plane to between -15° and +15°.

[0016] According to a particular aspect of this second embodiment, the first adjusting device includes a transmission tube generally coaxial with the longitudinal axis, the roller being mounted on the transmission tube and rotatably movable on the transmission tube about a rotation axis perpendicular to the longitudinal axis, the transmission tube including a first actuator including a first actuator chamber defined by a wall of the transmission tube and a first actuator piston received in the first actuator chamber and rotatably movable along the longitudinal axis within the first actuator chamber, and the free end of the first actuator piston being connected to the roller via a first connecting rod to pivot the roller relative to the transmission tube about the rotation axis and adjust the angle of the first plane relative to the vertical plane.

[0017] In a third embodiment of the invention, the roller is rotatably movable about the longitudinal axis, and the receiving portion takes the form of a plurality of independent receiving portions generally extending along the first plane, the root of each blade being received in one of the receiving portions, such that the blade and the roller pivot together about the longitudinal axis, and the first adjusting device is configured to adjust the angle of the first plane relative to the vertical plane to between -15° and +15°.

[0018] According to a specific aspect of this third embodiment, the first adjusting device further includes a transfer tube rotatably movable about the longitudinal axis, the roller being rotatably movable about the longitudinal axis and mounted on the transfer tube and rotatably movable about a rotation axis perpendicular to the longitudinal axis on the transfer tube, the first adjusting device further including an auxiliary transfer tube rotatably fixed relative to the longitudinal axis and coaxial with the transfer tube, the transfer tube being rotatably movable within the auxiliary transfer tube about the longitudinal axis, the auxiliary transfer tube including a second actuator, the second actuator including a second actuator chamber defined by a wall of the auxiliary transfer tube and a second actuator piston received in the second actuator chamber and rotatably movable within the second actuator chamber, and the free end of the second actuator piston being connected to the roller via a second link so as to pivot the roller relative to the transfer tube about the rotation axis and adjust the angle of the first plane relative to the vertical plane.

[0019] According to another specific aspect of this third embodiment, the roller has a lateral surface generally parallel to the first plane, and the first adjusting device includes a plate having a shape substantially corresponding to the shape of the lateral surface, the plate being coaxial with the roller, the plate being fixed about a longitudinal axis and rotatably relative to the roller, and the plate including a receiving portion configured to receive the end of the second connecting rod opposite to the second actuator piston.

[0020] According to a particular aspect of the invention, the system further includes a second means for adjusting the blade angle of the blades, and the second adjusting means is configured to move the roller in a translational manner along the longitudinal axis so as to adjust the blade angle of all blades of the propeller uniformly and simultaneously.

[0021] According to another specific aspect, the system includes a housing, and the second adjustment device includes a third actuator comprising:

[0022] - A third actuator chamber, which is coaxial with the longitudinal axis and defined by the wall of the housing, and

[0023] - A third actuator piston, formed from a portion of the transmission tube, is received within the third actuator chamber and is capable of translational movement along a longitudinal axis within the third actuator chamber.

[0024] Furthermore, the roller is designed to move along the longitudinal axis during the movement of the third actuator piston.

[0025] The present invention also proposes an aircraft comprising at least one propulsion system as described above. Attached Figure Description

[0026] The features of the invention mentioned above, as well as other features, will become more apparent when reading the following description of embodiments of the invention, which is given with reference to the accompanying drawings, in which:

[0027] Figure 1 This is a side view of an aircraft employing the aircraft propulsion system according to the present invention;

[0028] Figure 2 This is a cross-sectional side view of a propulsion system according to a first embodiment of the present invention;

[0029] Figure 3 This is a cross-sectional side view of a propulsion system according to a second embodiment of the present invention, with the first adjustment device in its initial position;

[0030] Figure 4 yes Figure 3 A cross-sectional side view of the propulsion system, with the first adjustment device in a pivot position;

[0031] Figure 5 yes Figure 3 A three-dimensional cross-sectional view of the propulsion system;

[0032] Figure 6 yes Figure 4 A three-dimensional cross-sectional view of the propulsion system;

[0033] Figure 7 This is a cross-sectional side view of a variant of the propulsion system according to a second embodiment of the present invention, with the first adjustment device in its initial position;

[0034] Figure 8 This is a cross-sectional side view of a propulsion system according to a third embodiment of the present invention, with the first adjustment device in its initial position; and

[0035] Figure 9 yes Figure 8 A cross-sectional side view of the propulsion system, with the first adjustment device in a pivot position. Detailed Implementation

[0036] Figure 1 An aircraft 9 comprising a fuselage 91 is shown, with wings 92 fixed to each side of the fuselage 91. At least one propulsion system 1 according to the invention is fixed below each wing 92 by means of a jet engine pylon 93.

[0037] In the following description, position-related terms refer to the aircraft being in its normal flight position, that is, as... Figure 1The flight position indicated in the text, and the "forward" position and "rear" position refer to the front and rear of the propulsion system 1 and are relative to the direction F of the forward movement of the aircraft 9 when the propulsion system 1 is operating.

[0038] In the following description and by convention, X represents the longitudinal direction of the propulsion system, which is horizontal when the aircraft is on the ground; Y represents the lateral direction, which is horizontal when the aircraft is on the ground; and Z represents the vertical direction, which is vertical when the aircraft is on the ground. These three directions X, Y and Z are orthogonal to each other.

[0039] In the embodiments of the invention described herein, the propulsion system 1 takes the form of an internal combustion engine, which includes a propeller 2 mounted on the drive shaft of the internal combustion engine. The propulsion system 1 has a vertical intermediate plane XZ and a horizontal intermediate plane XY.

[0040] like Figures 2 to 9 As depicted, the propulsion system 1 (hereinafter referred to as the system) of the aircraft 9 has a longitudinal axis A1 that extends generally parallel to axis X. System 1 includes a propeller 2 that rotates about the longitudinal axis A1 and includes a plurality of blades 20, each having a blade axis Ax that extends generally perpendicular to the longitudinal axis A1. The blade axis Ax is generally defined by a straight line passing through the root 201 of the blade and the tip (not depicted) of the blade, and the blades 20 are angled about the longitudinal axis A1.

[0041] According to the present invention, system 1 includes a first device 3 for adjusting the blade angle of blades 20, the first device 3 being configured to adjust the blade angle of each blade 20 according to the angular position of each blade 20 about the longitudinal axis A1 of system 1. The blade angle of a blade is defined by its orientation relative to the blade axis Ax. Therefore, the blade angle is adjusted by pivoting the blade 20 about its blade axis Ax.

[0042] For this purpose, the first adjusting device 3 includes a generally tubular roller 30 that is generally coaxial with the longitudinal axis A1. The roller 30 includes receiving portions 32a and 32b on its outer surface 31, the receiving portions 32a and 32b being configured to receive the root 201 of the blade 20. As described in more detail with reference to various embodiments, the receiving portions 32a and 32b may take the form of a groove or a plurality of notches extending generally along a first plane P1. The first plane P1 forms an angle α with a vertical plane PP, which is perpendicular to a reference plane P0 containing the longitudinal axis A1. The first plane P1 has a non-zero angle α, which is between -15° and +15°, particularly between -5° and +5°, for example, substantially equal to -2° or +2°. More precisely, the reference plane P0 is a plane generally parallel to the vertical intermediate plane XZ, while the vertical plane PP is a plane generally parallel to the vertical plane YZ.

[0043] During the rotation of the propeller 2, the inclination of the housings 32a and 32b along the first plane P1 along which they extend makes it possible to adjust the blade angle of the blade 20 according to the angular position of the blade 20 about the longitudinal axis A1.

[0044] In this way, the present invention can cyclically adjust (that is, repeatedly adjust in each rotation of the propeller 2) the blade angle of each blade 20 according to the angular position of each blade 20 about the longitudinal axis A1. For example, the blade angle of the blade 20 is different when the blade 20 is at the 3 o'clock, 6 o'clock, 9 o'clock or 12 o'clock position about the longitudinal axis A1.

[0045] This cyclic adjustment allows the blade angles of the blades 20 to be adjusted (i.e., changed) during the complete rotation of the propeller 2 about the longitudinal axis A1, thus enabling the propeller 2 to provide optimal thrust to the blades regardless of the flight phase of the aircraft 9. Furthermore, this adjustment of the blade angles according to the angular position of the blades about the longitudinal axis A1 allows different blade angles to be assigned to the rising and falling blades, with the aim of adjusting the load applied to each blade 20 of the propeller 2 and thus reducing the distortion of the flow entering the front of the propeller during the takeoff phase. This, in turn, significantly reduces the noise generated by the propeller 2 during this flight phase.

[0046] Figure 2This is a cross-sectional view on the horizontal plane XY, depicting a first embodiment of system 1 according to the invention. In this first embodiment, the roller 30 is fixed in rotation about the longitudinal axis A1, and the receiving portion 32a takes the form of a groove. The groove 32a is formed on the entire periphery of the roller 30, flush with the outer surface 31, and generally extends along the first plane P1. The root 201 of the blade 20 is received in the groove 32a, such that the blade 20 pivots about the roller 30 and about the longitudinal axis A1. Furthermore, the angle α of the first plane P1 relative to the vertical plane PP is fixed, non-zero, and between -15° and +15°, particularly between -5° and +5°, for example, substantially equal to -2° or +2°. Figure 2 In the example depicted, the angle α between the first plane P1 and the vertical plane PP is 5°.

[0047] Therefore, the blades 20 of the propeller 2 rotate about the roller 30, and the root 201 of the blades 20 moves in the groove 32a of the roller 30 during the rotation of the propeller 2. The groove 32a extends along a first plane P1, which is inclined at an angle α relative to the vertical plane PP, such that the movement of the root 201 of the blades 20 in the groove 32a during the complete rotation of the propeller 2 about the longitudinal axis A1 is not parallel to the vertical plane PP. Therefore, depending on the angular position of the blades 20, the root 201 of the blades 20 will find itself aligned with the vertical plane PP during the rotation of the propeller 2, and then offset to one side or the other side of the vertical plane PP (e.g., ...). Figure 2 (As depicted in the text). This movement of the blade root 201 relative to the vertical plane PP causes the blade angle of the blade 20 to change during the rotation of the propeller 2 about the longitudinal axis A1.

[0048] In this embodiment, the roller 30 is fixed in rotation relative to the axis Z. Therefore, the inclination of the groove 32a formed in the roller 30 defines the angle α between the first plane P1 and the vertical plane PP. Therefore, depending on the desired angle α, it is necessary to use a roller 30 with a corresponding groove 32a. The angle α of the groove 32a relative to the vertical plane PP (corresponding to the angle α of the first plane P1) is selected to obtain optimal performance in terms of thrust and noise generated by the propeller 2.

[0049] In this example, groove 32a extends in a generally straight manner and parallel to the first plane P1, although it is conceivable to use more complex grooves, such as grooves with curved portions, to manage more complex blade load effects (wing effects, inlet effects, etc.).

[0050] Furthermore, and as Figure 2As depicted, system 1 also includes a housing 70, which in this example forms the hub of propeller 2 and thus carries blades 20. The housing 70 rotates about a longitudinal axis A1 and therefore about a roller 30 that is fixed in rotation relative to the longitudinal axis A1. The housing 70 can be driven to rotate by, for example, a gearbox (not depicted) of propulsion system 1.

[0051] Figures 3 to 7 A second embodiment of the propulsion system 1 according to the present invention is depicted. More precisely, Figure 3 and Figure 4 A cross-sectional view of the system 1 on the horizontal plane XY is provided, wherein the first adjustment device 3 is in the initial position and the pivot position, respectively. Figure 5 and Figure 6 These are a three-dimensional view and a cross-sectional view of the system 1 on the horizontal plane XY, wherein the first adjustment device 3 is in the initial position and the pivot position, respectively. Figure 7 A variation of the second embodiment is described.

[0052] In this second embodiment, the roller 30 is fixed in rotation about the longitudinal axis A1, and the receiving portion 32a takes the form of a groove that generally extends along the first plane P1. As previously described, the groove 32a is formed on the entire periphery of the roller 30, flush with the outer surface 31, and generally extends along the first plane P1. The root 201 of the blade 20 is received in the groove 32a, such that during the rotation of the propeller 2, the blade 20 pivots about the roller 30 and about the longitudinal axis A1. The first adjustment device 3 is configured to adjust the angle α of the first plane P1 relative to the vertical plane PP to between -15° and +15°, particularly between -5° and +5°, for example, substantially equal to -2° or +2°. More precisely, the first adjustment device 3 is able to adjust the initial position ( Figure 3 and Figure 5 The pivot position (as depicted in the text) Figure 4 and Figure 6 The plane moves between the planes described in the diagram. In the initial position, the angle α between the first plane P1 and the vertical plane PP is zero (that is, in the initial position, the first plane P1 extends parallel to the vertical plane PP). In the pivot position, the angle α between the first plane P1 and the vertical plane PP is non-zero and lies between -15° and +15°.

[0053] In other words, the groove 32a extends along the first plane P1, which is here movable (in this case, pivotable) relative to the vertical plane PP by an angle α via the first adjusting device 3. When the first plane P1 is in the pivoted position, the movement of the root 201 of the blade 20 in the groove 32a during the complete rotation of the propeller 2 about the longitudinal axis A1 is therefore not parallel to the vertical plane PP. In this case, depending on the angular position of the blade 20, the root 201 of the blade 20 will find itself aligned with the vertical plane PP and then move to one side or the other side of the vertical plane PP (e.g., ...). Figure 4 (As depicted in the text). This movement of the blade root 201 relative to the vertical plane PP causes the blade angle of the blade 20 to change during the rotation of the propeller 2 about the longitudinal axis A1.

[0054] In this way, the first adjustment device 3 enables different adjustments to the blade angles of the propeller 2 blades 20 according to the flight phase of the aircraft. For example, during the cruise phase, the first adjustment device 3 can be positioned in its initial position such that the blade angles are generally the same for all blades 20. During the takeoff phase of the aircraft 9, the first adjustment device 3 can be positioned in a pivot position where the angle α between the first plane P1 and the vertical plane PP is non-zero and between -15° and +15°, particularly between -5° and +5°, for example, substantially equal to -2° or +2°, so that the blade angles of the blades 20 vary according to the angular position of the blades 20, thereby limiting, for example, noise generated by the propeller 2.

[0055] In this example, the groove 32a extends parallel to the first plane P1 in a generally straight manner, although it is conceivable to use a more complex groove 32a, such as a groove with curved portions, to manage more complex blade load effects (wing effects, inlet effects, etc.).

[0056] To enable the roller 30 to move from its initial position to its pivot position (and vice versa), the first adjusting device 3 includes a transmission tube 4 that is generally coaxial with the longitudinal axis A1. The roller 30 is mounted on the transmission tube 4 and is capable of rotating about an axis Az perpendicular to the longitudinal axis A1 on the transmission tube 4. Figure 5 and Figure 6 (As can be seen in the image) it moves in a rotating manner. More precisely, the axis of rotation Az of roller 30 is generally parallel to the vertical axis Z.

[0057] The transmission tube 4 includes a first actuator 41, which comprises a first actuator chamber 411 defined by a wall 413 of the transmission tube 4 and a first actuator piston 412 received in the first actuator chamber 411 and capable of translational movement within the first actuator chamber 411 along a longitudinal axis A1. The free end 414 of the first actuator piston 412 is connected to a roller 30 via a first link 415, such that the roller 30 pivots relative to the transmission tube 4 about a rotation axis Az as the first actuator piston 412 moves within the first actuator chamber 411. During the movement of the first actuator piston 412 within the first actuator chamber 411, the roller 30 pivots about the rotation axis Az (by being pushed or pulled by the first link 415, depending on the direction of movement of the first actuator piston 412), thereby adjusting the angle α of the first plane P1 relative to the vertical plane PP.

[0058] In order to enable the first actuator piston 412 to move within the first actuator chamber 411, the transmission conduit 4 includes a passage for supplying fluid, i.e., supplying fluid to the first actuator chamber 411. The first actuator 41 may be a single-acting type and include a spring (as depicted herein) or it may be a double-acting type (not depicted).

[0059] In addition, such as Figures 3 to 6 The system 1 according to the second embodiment of the present invention, as depicted herein, includes a housing 70. In this example, the housing 70 includes a hub 701 that carries the blade 20 and a fixed base 702 that extends coaxially with the longitudinal axis A1. The hub 701 is rotatable about the fixed base 702 about the longitudinal axis A1.

[0060] Hub 701 rotates about longitudinal axis A1 and thus about roller 30. Hub 701 is driven to rotate, for example, by a gearbox (not depicted) of propulsion system 1. In this example, the wall 413 of the transmission tube 4 defining the first actuator chamber 411 is outside the housing 70. Only the first connecting rod 415 extends from the free end 414 of the first actuator piston 412 to the roller 30 located inside the housing 70.

[0061] exist Figure 7 In this variant of the second embodiment depicted, system 1 further includes a housing 70, which in this example forms a hub carrying the blade 20. The housing 70 rotates about a longitudinal axis A1, and thus about the transmission tube 4 and roller 30, which are rotationally fixed relative to the longitudinal axis A1. In this variant, there is no fixed base, and the wall 413 of the transmission tube 4 defining the first actuator chamber 411 is disposed within the housing 70. This simplifies the structure of system 1 because the first link 415 is no longer required to pass through the fixed base, or to form a connection between the fixed base and the hub, allowing the hub to rotate about the fixed base.

[0062] Figure 8 and Figure 9 A third embodiment of the propulsion system 1 according to the present invention is depicted. More precisely, Figure 8 and Figure 9 A cross-sectional view of the system 1 on the horizontal plane XY is depicted, wherein the first adjustment device 3 is in the initial position and the pivot position, respectively.

[0063] In this third embodiment, the roller 30 rotates about the longitudinal axis A1, and the receiving portion 32b takes the form of multiple recesses 32b, each recess 32b being an independent receiving portion arranged flush with the outer surface 31 of the roller 30 and generally extending along the first plane P1. Therefore, the root 201 of each blade 20 is received in one of the recesses 32b, causing the blade 20 to pivot together with the roller 30 about the longitudinal axis A1. In other words, during the rotation of the propeller 2, the roller 30 rotates together with the blade 20 about the longitudinal axis A1.

[0064] The first adjustment device 3 is configured to adjust the angle α of the first plane P1 relative to the vertical plane PP to between -15° and +15°, particularly between -5° and +5°, for example, substantially equal to -2° or +2°. As previously described, the first adjustment device 3 is capable of adjusting the angle α of the first plane P1 relative to the vertical plane PP to between -15° and +15°, particularly between -5° and +5°, for example, substantially equal to -2° or +2°. Figure 8 The pivot position (as depicted in the text) Figure 9 The plane moves between the planes described in the diagram. In the initial position, the angle α between the first plane P1 and the vertical plane PP is zero (that is, the first plane P1 extends parallel to the vertical plane PP). In the pivot position, the angle α between the first plane P1 and the vertical plane PP is non-zero and lies between -15° and +15°.

[0065] In other words, the notch 32b extends along the first plane P1, which is here movable (in this case, pivotable) relative to the vertical plane PP by an angle α via the first adjusting device 3. When the first plane P1 is in the pivoted position, the movement of the root 201 of the blade 20 in the notch 32b during the complete rotation of the propeller 2 about the longitudinal axis A1 is therefore not parallel to the vertical plane PP. In this case, depending on the angular position of the blade 20, the root 201 of the blade 20 will find itself aligned with the vertical plane PP and then move to one side or the other side of the vertical plane PP (e.g., ...). Figure 4 (As depicted in the text). This movement of blade 201 relative to the vertical plane PP causes the blade angle of blade 20 to change during the rotation of propeller 2 about longitudinal axis A1.

[0066] In this way, the first adjustment device 3 enables different adjustments to the blade angles of the propeller 2 blades 20 during the flight phase of the aircraft. For example, during the cruise phase, the first adjustment device 3 can be positioned in its initial position such that the blade angles are generally the same for all blades. During the takeoff phase of the aircraft 9, the first adjustment device 3 can be positioned in a pivot position where the angle α between the first plane P1 and the vertical plane PP is non-zero and between -15° and +15°, particularly between -5° and +5°, for example, substantially equal to -2° or +2°, so that the blade angles of the blades 20 vary according to the angular position of the blades 20, thereby limiting, for example, noise generated by the propeller 2.

[0067] The first adjusting device 3 includes a transmission tube 4 capable of rotating about a longitudinal axis A1. A roller 30 is also capable of rotating about the longitudinal axis A1 and is mounted on the transmission tube 4, capable of rotating about a rotation axis Az perpendicular to the longitudinal axis A1. More precisely, the rotation axis Az of the roller 30 is generally parallel to the vertical axis Z.

[0068] The first adjusting device 3 also includes an auxiliary transmission tube 5, which is fixed in rotation relative to the longitudinal axis A1 and coaxial with the transmission tube 4. More precisely, the transmission tube 4 is capable of rotating about the longitudinal axis A1 inside the auxiliary transmission tube 5.

[0069] In other words, the first adjusting device 3 includes an auxiliary transmission tube 5, which is coaxial with the longitudinal axis A1 and fixed in rotation relative to the longitudinal axis A1. A transmission tube 4 is installed inside the auxiliary transmission tube 5 and is capable of rotating about the longitudinal axis A1. Therefore, the transmission tube 4, the roller 30, and the blade 20 rotate together about the longitudinal axis A1.

[0070] To allow the roller 30 to move from its initial position to its pivot position (and vice versa), the auxiliary transmission tube 5 includes a second actuator 51 comprising a second actuator chamber 511 defined by a wall 513 of the auxiliary transmission tube 5 and a second actuator piston 512 received in the second actuator chamber 511 and capable of translational movement within the second actuator chamber 511. The free end 514 of the second actuator piston 512 is rigidly fixed to the roller 30 by a second connecting rod 515, so that the roller 30 pivots relative to the transmission tube 4 about the rotation axis Az and adjusts the angle α of the first plane P1 relative to the vertical plane PP.

[0071] Therefore, during the movement of the second actuator piston 512 in the second actuator chamber 511, the roller 30 pivots (by being pushed or pulled by the second link 515, depending on the direction of movement of the second actuator piston 512), thereby adjusting the angle α of the first plane P1 relative to the vertical plane PP.

[0072] To enable the second actuator piston 512 to move within the second actuator chamber 511, the transmission pipe 4 and the auxiliary transmission pipe 5 include passages for supplying fluid, i.e., supplying fluid to the second actuator chamber 511. The second actuator 51 may be a single-acting type and include a spring (as depicted herein) or it may be a double-acting type (not depicted).

[0073] The auxiliary transmission tube 5 is fixed relative to the longitudinal axis A1, and the roller 30 is movable about the longitudinal axis A1, therefore it is necessary to provide a proper connection between these two components. For this purpose, the roller 30 has a lateral surface 33 that is generally parallel to the first plane P1. The first adjusting device 3 also includes a plate 6 having a shape substantially corresponding to the shape of the lateral surface 33. The plate 6 is coaxial with the roller 30. Furthermore, the plate 6 is fixed in rotation about the longitudinal axis A1 and relative to the roller 30. Finally, the plate 6 includes a receiving portion 60 configured to receive the end of the second connecting rod 515 opposite to the second actuating piston 512.

[0074] In this way, plate 6 can thus pivot together with roller 30 about the axis of rotation Az of roller 30. Roller 30 can therefore rotate freely relative to auxiliary transmission tube 5, and the second link 515 can cause roller 30 to pivot about the axis of rotation Az by pushing or pulling plate 6, which is rigidly connected to roller 30.

[0075] This third embodiment therefore provides an alternative to the above solution, wherein the roller 30 rotates together with the blade 20 of the propeller 2.

[0076] In addition, such as Figure 8 and Figure 9 As depicted, system 1 also includes a housing 70, which in this example forms the hub of propeller 2 and thus carries blades 20. The housing 70 rotates about a longitudinal axis A1 together with rollers 30 and transmission tube 4. Here, the housing 70 is rotatably driven by a main shaft 80, which is connected, for example, to a gearbox (not depicted) of propulsion system 1.

[0077] In a manner compatible with all the embodiments described above, the propulsion system 1 of the present invention further includes a second device 7 for adjusting the blade angle of the blades 20, the second device 7 being configured to move the roller 30 in a translational manner along the longitudinal axis A1 so as to uniformly and simultaneously define the blade angle of all blades 20 of the propeller 2.

[0078] Therefore, the present invention can combine (via the second adjustment device 7) uniform and simultaneous adjustment of all blades 20 with additional independent adjustment of the blade angle of each blade according to the angular position of each blade about the longitudinal axis A1 (via the first adjustment device 3). In other words, the present invention provides additional adjustment of the blade angle of the blades 20 in order to optimize the performance of the propulsion system 1 on the one hand, and optimize the noise generated during the full flight phase of the aircraft on the other hand.

[0079] To enable the roller 30 to move in a translational manner along the longitudinal axis A1, the system 1 includes a housing 70, and the second adjustment device 7 includes a third actuator 71. The third actuator 71 specifically includes:

[0080] - A third actuator chamber 711, which extends coaxially with the longitudinal axis A1 and is defined by the third wall 713 of the housing 70, and

[0081] - The third actuator piston 712 is formed by a portion of the transmission tube 4. The third actuator piston 712 is received in the third actuator chamber 711 and moves in a translational manner along the longitudinal axis A1 in the third actuator chamber 711.

[0082] Therefore, the roller 30 is designed to move along the longitudinal axis A1 during the movement of the third actuator piston 712. Thus, during the movement of the third actuator piston 712 within the third actuator chamber 711, the roller 30 moves along the longitudinal axis A1 in a translational manner (forward or backward). This movement of the roller 30 along the longitudinal axis A1 allows for adjustment of the position of the root 201 of the propeller blades 20, thereby adjusting the blade angle.

[0083] In order to enable the third actuator piston 712 to move within the third actuator chamber 711, the transmission pipe 4 includes a channel for supplying fluid, i.e., supplying fluid to the third actuator chamber 711. The third actuator 71 may be a double-acting type (as depicted herein) or a single-acting type (not depicted).

[0084] In the above-described first, third, and second embodiments (and references) Figure 7 In the variant described, the outer casing 70 forms the hub of the propeller 2, and the third chamber 711 is formed within the outer casing 70. Therefore, the hub rotates about the longitudinal axis A1.

[0085] Second implementation method (and reference) Figures 3 to 6 In the described variant, the third wall 713 of the outer casing 70 is formed in a fixed base 702 that does not rotate about the longitudinal axis A1.

[0086] In the second and third embodiments described above, the connection between the roller 30 and the transmission tube 4 is preferably a ball joint connection in order to limit the friction between the roller 30 and the transmission tube 4.

[0087] Regardless of the embodiment of the invention, each root 201 of the blade 20 preferably carries a pin 202, which is designed to be received in the receiving portions 32a, 32b of the roller 30. In the depicted example, and to limit friction between the blade 20 and the receiving portions 32a, 32b of the roller 30, the pin 202 has a generally circular shape. It is also conceivable to use a lubricant to limit friction between the blade 20 and the receiving portions 32a, 32b of the roller 30.

[0088] In order to limit friction and thereby improve the efficiency of propulsion system 1, a bearing mechanism 81 is preferably used between components that rotate relative to each other (e.g., between the fixed base 702 and the hub 701 or between the plate 6 and the roller 30).

Claims

1. A propulsion system (1) for an aircraft, the propulsion system (1) having a longitudinal axis (A1) and comprising: - A propeller (2) capable of rotating about the longitudinal axis (A1), the propeller (2) comprising a plurality of blades (20), each of the plurality of blades (20) having a blade axis (Ax) generally perpendicular to the longitudinal axis (A1), the blades (20) being distributed at an angle relative to the longitudinal axis (A1); as well as - A first device (3) for adjusting the blade angle of the blade (20), the first adjusting device (3) being configured to adjust the blade angle of each blade (20) according to the angular position of each blade (20) about the longitudinal axis (A1). The first adjusting device (3) is characterized in that it includes a generally tubular roller (30) that is generally coaxial with the longitudinal axis (A1), the roller (30) including receiving portions (32a, 32b) on its outer surface (31), the receiving portions (32a, 32b) being configured to receive the root (201) of the blade (20), the receiving portions (32a, 32b) extending along a first plane (P1), the first plane (P1) being at a non-zero angle (α) between -15° and +15° relative to a plane (PP) perpendicular to a reference plane (P0) containing the longitudinal axis (A1).

2. The system (1) according to claim 1, characterized in that, The roller (30) is fixed in rotation about the longitudinal axis (A1), and the receiving portion (32a) takes the form of a groove that generally extends along the first plane (P1), in which the root (201) of the blade (20) is received, such that the blade (20) pivots about the roller (30) and about the longitudinal axis (A1), and the angle (α) of the first plane (P1) relative to the vertical plane (PP) is fixed, non-zero, and between -15° and +15°.

3. The system (1) according to claim 1, characterized in that, The roller (30) is fixed in rotation about the longitudinal axis (A1), and the receiving portion (32a) takes the form of a groove that generally extends along the first plane (P1), in which the root (201) of the blade (20) is received, such that the blade (20) pivots about the roller (30) and about the longitudinal axis (A1), and the first adjusting device (3) is configured to adjust the angle (α) of the first plane (P1) relative to the vertical plane (PP) to between -15° and +15°.

4. The system (1) according to claim 3, characterized in that, The first adjusting device (3) includes a transmission tube (4) generally coaxial with the longitudinal axis (A1), the roller (30) being mounted on the transmission tube (4) and rotatably movable on the transmission tube (4) about a rotation axis (Az) perpendicular to the longitudinal axis (A1), the transmission tube (4) including a first actuator (41), the first actuator (41) including a first actuator chamber (411) defined by a wall (413) of the transmission tube (4) and received in the first actuator chamber. A first actuator piston (412) is located in the actuator chamber (411) and is capable of translational movement along the longitudinal axis (A1) in the first actuator chamber (411), and the free end (414) of the first actuator piston (412) is connected to the roller (30) via a first link (415) so that the roller (30) pivots about the axis of rotation (Az) relative to the transmission tube (4) and adjusts the angle (α) of the first plane (P1) relative to the vertical plane (PP).

5. The system (1) according to claim 1, characterized in that, The roller (30) is rotatably movable about the longitudinal axis (A1), and the receiving portion (32b) takes the form of a plurality of independent receiving portions generally extending along the first plane (P1), the root (201) of each blade (20) being received in one of the receiving portions (32b) such that the blade (20) pivots together with the roller (30) about the longitudinal axis (A1), and the first adjusting device (3) is configured to adjust the angle (α) of the first plane (P1) relative to the vertical plane (PP) to between -15° and +15°.

6. The system (1) according to claim 5, characterized in that, The first adjusting device (3) includes a transfer tube (4) rotatably movable about the longitudinal axis (A1), the roller (30) rotatably movable about the longitudinal axis (A1) and rotatably movable on the transfer tube (4) about a rotation axis (Az) perpendicular to the longitudinal axis (A1). The first adjusting device (3) further includes an auxiliary transfer tube (5) rotatably fixed relative to the longitudinal axis (A1) and extending coaxially with the transfer tube (4). The transfer tube (4) is rotatably movable inside the auxiliary transfer tube (5) about the longitudinal axis (A1). The auxiliary transfer tube (5) includes a first... The second actuator (51) includes a second actuator chamber (511) defined by the wall (513) of the auxiliary transmission tube (5) and a second actuator piston (512) received in the second actuator chamber (511) and movable in the second actuator chamber (511) in a translational manner. The free end (514) of the second actuator piston (512) is connected to the roller (30) by a second link (515), thereby causing the roller (30) to pivot about the axis of rotation (Az) relative to the transmission tube (4) and adjust the angle (α) of the first plane (P1) relative to the vertical plane (PP).

7. The system (1) according to claim 6, characterized in that, The roller (30) has a lateral surface (33) that extends generally parallel to the first plane (P1), and the first adjusting device (3) includes a plate (6) having a shape that substantially corresponds to the shape of the lateral surface (33), the plate (6) being coaxially mounted with the roller (30), the plate being fixed in rotation about the longitudinal axis (A1) and relative to the roller (30), and the plate (6) including a receiving portion (60) configured to receive the end of the second connecting rod (515) opposite to the second actuator piston (512).

8. The system (1) according to any one of claims 1 to 7, characterized in that, It also includes a second device (7) for adjusting the blade angle of the blades (20), the second adjusting device (7) being configured to move the roller (30) in a translational manner along the longitudinal axis (A1) so as to adjust the blade angle of all the blades (20) of the propeller (2) uniformly and simultaneously.

9. The system (1) according to claim 8, characterized in that, The system (1) includes a housing (70), and the second regulating device (7) includes a third actuator (71), the third actuator (71) comprising: - A third actuator chamber (711), said third actuator chamber (711) being coaxial with said longitudinal axis (A1) and defined by the wall (713) of said housing (70), and - A third actuator piston (712), which is formed from a portion of the transmission tube (4), is received in the third actuator chamber (711) and is capable of translational movement in the third actuator chamber (711) along the longitudinal axis (A1), wherein the roller (30) is designed to move along the longitudinal axis (A1) during the movement of the third actuator piston (712).

10. An aircraft (9) comprising at least one propulsion system (1) according to any one of claims 1 to 9.

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