Variable pitch changing device for a turbine blade, turbomachine and aircraft having it

Abstract

A device (1) for changing the pitch of a variable-pitch blade (100), comprising: a cylinder (3), having a fixed part (31) and a movable part (32), a linkage mechanism (4) connecting the part (32) to the blade (100), a pitch locking device (7) suitable for immobilizing the part (32) and comprising a screw (71), a nut (74) whose translation along a determined direction (S1) causes the screw (71) to rotate in a determined direction (S10) of rotation, and a braking device (9) suitable for being actuated to prevent the screw (71) from rotating in the determined direction (S10) of rotation; an electric motor (6) mechanically configured to rotate the screw (71) in the other direction of rotation (S20) so as to move the part (32) along the other direction (S2) to an angular position for feathering the blade (100). Figure for the abbreviation: Figure 1

Description

Title of the invention: Device for changing the pitch of a variable-pitch turbine blade, turbomachine and aircraft having it

[0001] TECHNICAL BACKGROUND

[0002] The invention relates to a device for changing the pitch of at least one variable-pitch turbine blade of a turbomachine, a turbomachine comprising this device and an aircraft comprising this turbomachine.

[0003] The field of the invention relates to aircraft turbomachinery, in particular turbojets or turboprops.

[0004] Such a pitch-changing device is known from document WO 2023 / 247907, which describes a pitch-changing mechanism for adjusting the angular position of at least one variable-pitch blade about a blade pivot axis, said pitch-changing mechanism comprising: - a fixed frame relative to the pivot axis, - a control cylinder comprising a fixed part attached to the frame and a movable part in translation along a longitudinal axis relative to the fixed part between a retracted position and an extended position. - a linking system connecting the moving part to the variable-pitch blade suitable for conversion:

[0005] a translation of the moving part along the longitudinal axis in a first direction by a rotation of the blade with variable pitch around the pivot axis towards the sail position, and

[0006] a translation of the moving part along the longitudinal axis in a second direction opposite to the first direction in a rotation of the variable pitch blade around the pivot axis towards a feathering position; - a pitch locking device designed to block the translation of the moving part relative to the fixed part in at least one direction,

[0007] the step locking device comprising: - a support element, movable in translation relative to the frame along the longitudinal axis between an operating position and a locking position, - a spring-loaded return device that pulls the support member back into its locking position, - a retaining device to maintain the support member in its operating position under normal operating conditions, the retaining device comprising a counterbalancing cylinder a counterbalancing chamber supplied with control fluid at the third pressure to counterbalance the stress on the return device, and - a screw-nut system with: • a screw fixed in translation to the support member and mounted to rotate freely about the longitudinal axis relative to the support member, the screw having a stop surface which is at a distance from the frame when the support member is in the operating position and in contact with the frame when the support member is in the locked position, and • a nut fixed to the moving part and coaxial with the screw, the nut cooperating with the screw such that a translation of the nut along the longitudinal axis causes the screw to rotate around the longitudinal axis, - the cylinder comprising a piston dividing said internal cavity of the cylinder into two contiguous fluidic chambers, each containing a control fluid, these two chambers being connected to a control fluid pilot circuit, to control the movement of the moving part relative to the fixed part by means of a control fluid pressure generator, - the pilot circuit comprising a pressure generator equipped with a main pump and a return line to evacuate the depressurized control fluid, a main reservoir configured to collect depressurized control fluid from the return line and supplying the pressure generator, and an auxiliary reservoir configured to collect depressurized control fluid from the return line and supplying an auxiliary pump,and a backup circuit capable of supplying the first fluidic chamber with control fluid so as to move the piston to its deployed position in the event of a pressure generator failure.

[0008] This control thus makes it possible to achieve a feathering of the blade in the event of failure of the pressure generator of the control fluid in the control circuit of the pitch change mechanism.

[0009] In this case, an uncontrolled locking step is carried out during which, due to the failure of the control fluid pressure generator, the pressure in the counterbalancing chamber decreases and is therefore no longer sufficient to counterbalance the stress on the return device, which thus drives the support member towards its locking position.

[0010] This uncontrolled locking step is followed by a blower safety step, during which the backup circuit is activated and supplies the first fluidic chamber with control fluid so as to increase the fluidic pressure in this chamber. Under the effect of this pressure increase, the piston moves towards its retracted position, carrying with it the screw and the support member, which returns to its operating position. The piston is therefore no longer immobilized and can continue to move downstream until the blades reach the feathering position.

[0011] A drawback of this mechanism known from document WO 2023 / 247907 is the presence of potential common failure modes between, on the one hand, the main control fluid circuit consisting of the main pump of the generator and the main reservoir and, on the other hand, the auxiliary control fluid circuit consisting of the auxiliary pump and the auxiliary reservoir (failure of the control fluid chain supplying the cylinder in particular), despite the presence of the spring.

[0012] Other known systems use weights at the base of the blade, which allow the blade to passively return to the feathered position in the event of a loss of hydraulic pressure in the blade actuation hydraulic circuit. A major drawback of these systems is that they lead to an increase in the mass of the turbomachine and therefore to a significant reduction in the overall performance of the turbomachine. These solutions are therefore unsuitable in the current context in which regulations on aircraft energy efficiency are becoming increasingly stringent. Summary of the invention

[0013] An objective of the invention is to obtain a pitch changing device for at least one variable pitch turbine blade, a turbomachine comprising this device, and an aircraft, which overcome the disadvantages mentioned above.

[0014] To this end, a first object of the invention is a pitch-changing device for adjusting the angular pivoting position of at least one variable-pitch turbomachine blade around a first pivoting axis of the blade, the device comprising: a frame fixed relative to the first pivoting axis, an actuating cylinder, having a first part fixed relative to the frame and a second part that can be moved linearly along an actuation direction of the cylinder relative to the first part, a linking mechanism connecting the second part of the cylinder to the blade for converting a linear displacement of the second part of the cylinder along the actuation direction into a rotation of the blade around the first pivoting axis, a pitch-locking device suitable for immobilizing the linear displacement of the second part of the cylinder relative to the first fixed part in a determined direction of the actuation direction of the cylinder,the step locking device comprising: ,

[0015] a screw mounted to rotate freely around the direction of actuation of the cylinder, a nut fixed to the second part of the cylinder and coaxial with the screw, the nut cooperating with the screw such that a translation of the nut along the determined direction of actuation causes the screw to rotate in a determined direction of rotation around the direction of actuation, and another translation of the nut in a different direction opposite to the determined direction causes the screw to rotate in a different direction of rotation opposite to the determined direction of rotation around the direction of actuation, and a braking device, which is capable of being actuated to act on the screw so as to immobilize the rotation of said screw in the determined direction of rotation around the direction of actuating the cylinder; characterized in that The device includes an electric motor mechanically coupled to the screw of the pitch locking device. the electric motor having a control input, the electric motor being configured to rotate the screw in the opposite direction of rotation to the determined direction of rotation in order to linearly move the nut in the opposite direction to the determined direction of actuation, so as to move the second part of the cylinder in the opposite direction to the determined direction of actuation to a first prescribed position relative to the first part, when a prescribed actuation command is present at the control input, the first prescribed position corresponding to an angular position of the blade feathering relative to the first pivot axis.

[0016] Thanks to the invention, the auxiliary system, comprising the electric motor, the screw, and the nut, can ensure the return of the blade to the first prescribed position corresponding to the blade's feathering angular position and is separate from the control fluid circuit, thus avoiding potential common failure modes with the control circuit. The return movement of the variable-pitch blade to the first prescribed position corresponding to the feathering angular position can therefore be controlled independently of the control fluid circuit.

[0017] Furthermore, there is a synergy between this auxiliary system and the pitch locking device. The screw and nut can thus be used both by the pitch locking device so that the latter, through the braking device acting on the screw, immobilizes the linear displacement of the second part of the cylinder relative to the first fixed part in the determined direction of the cylinder's actuation, and also by the electric motor so that, when a When a prescribed actuation command is present at the motor's control input, the motor rotates the screw to linearly move the nut in the opposite direction, thus moving the second part of the cylinder in this other direction until it reaches the first prescribed position, corresponding to the blade's feathering angular position, when a prescribed actuation command is present at the motor's control input. This allows the screw and nut to be integrated into these two systems, which have two different functions.

[0018] In other words, the present invention proposes an auxiliary system for re-feathering the blades which consists of electrically motorizing the screw of the pitch locking device in order to allow re-feathering of the blade independently of other re-feathering systems.

[0019] This solution makes it possible to resolve the technical problems mentioned above by allowing an auxiliary system for the feathering of the control fluid circuit and by not requiring the use of a mass at the base of the blade for the feathering return.

[0020] According to one embodiment of the invention, the angular position of the feathering of the blade corresponds to the angular position in which the angle of attack of the airflow at a leading edge of the blade is minimal.

[0021] The invention is advantageously complemented by the following features, taken individually or in any of their technically possible combinations:

[0022] - the angular position of the feathering of the blade corresponds to the position angular angle in which the angle of attack of the airflow at a leading edge of the blade is minimal;

[0023] - the screw of the pitch locking device has a thread around a second axis of rotation parallel to the direction of actuation and is connected to a shaft of the electric motor so that said screw is driven in rotation around the second axis of rotation when the shaft of the electric motor is rotated; - the nut of the pitch locking device cooperates by screwing with the thread of the screw and is locked in rotation relative to the screw, to drive the nut in translation along the second axis of rotation when the screw is driven in rotation around the second axis of rotation;

[0024] - the device includes a linking mechanism connecting the nut to the second part of the cylinder to convert the translation of said nut along the direction of actuation into the linear displacement of the second part of the cylinder along the direction of actuation;

[0025] - the electric motor is configured to rotate the shaft in the opposite direction of rotation, the opposite of the determined direction of rotation, to cause linear movement the nut in the other direction, opposite to the determined direction of actuation until a second prescribed position corresponding to the first prescribed position of the second part of the cylinder relative to the first part, when the prescribed actuation command is present at the control input;

[0026] - the pitch locking device comprises rotating rollers between the screw and the nut;

[0027] - the pitch locking device comprises rotating balls between the screw and the nut;

[0028] - the second part of the cylinder delimits a first chamber and a second chambers which are separated from each other in a manner sealed against a control fluid by the first part of the cylinder;

[0029] - the device further includes a control circuit for the selective sending of the pressurized control fluid from a pressurized control fluid reservoir either to the first chamber to control the linear movement of the second part of the cylinder in the opposite direction to the direction determined according to the actuation direction relative to the first part, or to the second chamber to control the linear movement of the second part of the cylinder in the direction determined according to the actuation direction relative to the first part;

[0030] - the control circuit is specific to the selective sending of the control fluid under pressure from the pressurized control fluid reservoir to the braking device to control the locking of the screw's rotation around the actuation direction in the determined direction of rotation when the braking device is actuation;

[0031] - the braking device, capable of being actuated to act on the screw so as to immobilizing the rotation of said screw in the determined direction of rotation around the direction of actuation of the cylinder, includes a friction braking mechanism;

[0032] - the braking device, which is capable of being actuated to act on the screw so as to immobilizing the rotation of said screw in the determined direction of rotation around the direction of actuation of the cylinder, includes a braking mechanism by roller system;

[0033] - the pitch changing device includes a power supply, suitable for supply electrical power to the electric motor.

[0034] According to another aspect of the invention, a turbomachine is proposed, comprising a stator, a rotor and a rotating part comprising a blower, the blower comprising at least one variable pitch blade and a pastel changing device as described above, the rotating part and the rotor being mounted to rotate about a third axis of rotation relative to the stator.

[0035] An electrical power supply, capable of providing electrical energy to the electric motor, may be provided in the rotating part containing the blower.

[0036] Alternatively or complementaryly, an electrical power supply, capable of providing electrical energy to the electric motor, may be provided in the stator, a rotating link interface, allowing the electrical connection of the electric motor to the electrical power supply, being provided between the rotating part and the stator.

[0037] According to another aspect of the invention, an aircraft is proposed comprising at least one turbomachine as described above, and a computer, which is connected to the control input and capable of generating the prescribed actuation command to send the prescribed actuation command to the control input.

[0038] According to another aspect of the invention, a method is proposed for adjusting the angular position of the pivoting of at least one variable-pitch blade of the aircraft turbomachine as described above around the first pivoting axis, the pitch-changing device further comprising a control circuit for the selective delivery of a pressurized control fluid from a pressurized control fluid reservoir either to the first chamber to control the linear displacement of the second part of the cylinder in the opposite direction to the direction determined along the actuation direction relative to the first part, or to the second chamber to control the linear displacement of the second part of the cylinder in the direction determined along the actuation direction relative to the first part, the method comprising the following steps: sending, by the computer, a first command to the control circuit to send the pressurized control fluid from the pressurized control fluid reservoir to either the first chamber or the second chamber, to cause the linear movement of the second part of the cylinder along the actuation direction relative to the first part until an adjustment position corresponding to a prescribed angular position of the blade around the first pivot axis, sending, by the computer, the prescribed actuation command to the control input of the electric motor, to rotate the screw in the opposite direction of rotation to the determined direction of rotation in order to linearly move the nut in the opposite direction to the determined direction along the actuation direction,in order to linearly move the second part of the cylinder in the opposite direction to the determined direction of actuation until it reaches the first prescribed position relative to the first part, thereby causing the blade to pivot about the first pivot axis, from the angular position of the set position to the angular position of the blade feathering corresponding to the first prescribed position. BRIEF DESCRIPTION OF THE FIGURES

[0039] The invention will be better understood upon reading the following description, given solely by way of non-limiting example with reference to the figures below of the attached drawings.

[0040] [Fig.1] represents a schematic vertical cross-sectional view of an air flow measurement device in an air passage according to an embodiment of the invention in air extraction.

[0041] [Fig.1] represents a schematic axial cross-sectional view of a pitch changing device according to an embodiment of the invention.

[0042] [Fig.2] represents a schematic axial cross-sectional view of a pitch changing device according to an embodiment of the invention.

[0043] [Fig.3] represents a schematic axial cross-sectional view of a first example of a turbomachine in which the pitch change device can be provided according to an embodiment of the invention.

[0044] [Fig.4] represents in perspective an aircraft, where the turbomachine can be provided according to an embodiment of the invention.

[0045] [Fig.5] represents a schematic perspective view of a second example of a turbomachine in which the pitch changing device can be provided according to an embodiment of the invention.

[0046] [Fig.6] represents a cross-sectional view of a variable pitch blade, the angular position of which can be modified by the pitch changing device according to an embodiment of the invention.

[0047] [Fig.7] represents a flowchart of a method for adjusting the angular position of a variable pitch blade according to an embodiment of the invention.

[0048] Embodiments of a pitch-changing device 1 according to the invention are described in more detail below with reference to Figures 1 and 2. DETAILED DESCRIPTION

[0049] The pitch changing device 1 is used to modify an angular pivoting position of one (or more) variable pitch blade 100 of a turbomachine T around a first pivoting axis 110 of this blade 100 relative to a frame 2. The frame 2 is fixed relative to the first pivoting axis 110.

[0050] The pitch changing device 1 includes an actuating cylinder 3 for rotating the blade 100 around the first pivot axis 110 relative to the frame 2. The actuating cylinder 3 has a first part 31, which is fixed relative to the frame 2. The actuating cylinder 3 has a second part 32, which is linearly movable along a direction 33 of actuating the cylinder 3 relative to the first part 31.

[0051] Typically, the second part 32 delimits a first control fluid receiving chamber 34 and a second control fluid receiving chamber 35, which are separated from each other in a manner sealed to the control fluid by the first part 31. The first part 31 is located along the direction 33 of actuation between a first end 36 of the second part 32, delimiting the first chamber 34, and a second end 37 of the second part 32, delimiting the second chamber 35.

[0052] The actuating cylinder 3 can be a hydraulic cylinder. It is connected to a control circuit 5 allowing the selective sending of pressurized control fluid from a pressurized control fluid reservoir 51 either to the first chamber 34 to control a linear displacement, i.e. a translation, of the second part 32 of the cylinder 3 in a first direction S2 of the actuating direction 33 relative to the first part 31, or to the second chamber 35 to control the linear displacement of the second part 32 of the cylinder 3 in a second direction SI of the actuating direction 33 (opposite of the first direction S2) relative to the first part 31.

[0053] The control circuit 5 includes, for example, a block 53 of hydraulic servovalves, which is connected to the reservoir 51 and which allows control fluid to be sent by a pump 54 into control fluid lines 52 either into the first chamber 51 or into the second chamber 35. In an embodiment where the cylinder 3 is a hydraulic cylinder, the control fluid is, for example, pressurized oil. In an alternative embodiment where the cylinder 3 is a pneumatic cylinder, the control fluid could be a compressed gas.

[0054] For example, in Figures 1 and 2, the first part 31 can be formed by an inner piston (or an inner wall) of the cylinder 3, while the second part 32 can be formed by an outer wall of the cylinder 3, this outer wall surrounding the piston (or surrounding the inner wall).

[0055] In other embodiments, not shown, the second part 32 could be formed by an inner piston (or an inner wall) of the cylinder 3, while the first part 31 could be formed by an outer wall of the cylinder 3, this outer wall surrounding the piston (or surrounding the inner wall).

[0056] The pitch-changing device 1 includes a linkage mechanism 4 connecting the second part 32 of the cylinder 3 to the blade 100 to convert the linear displacement of the second part 32 of the cylinder 3 along the actuation direction 33 into a pivoting, i.e., a rotation, of the blade 100 about the first pivot axis 110. The first pivot axis 110 may not be oriented in a direction parallel to the actuation direction 33. The linkage mechanism 4 may include one or more joints 41 and / or one or more connecting rods 42 between the second part 32 of the cylinder 3 and the blade 100. The linking mechanism 4 is connected to the foot 111 of the blade 100. The foot 111 of the blade 100 is for example pivotally mounted in a rotating bearing 21 on the outer edge of the frame 2.

[0057] The pitch-changing device 1 includes a pitch-locking device 7. The pitch-locking device 7 is designed to immobilize, i.e., prevent, the linear displacement of the second part 32 of the cylinder 3 relative to the first fixed part 31 in a determined direction of the actuation direction 33 of the cylinder 3, for example, the first direction SL

[0058] The pitch locking device 7 comprises a screw 71, a nut 74 and a braking device 9. The screw 71 is mounted to rotate freely around the direction 33 of actuation of the cylinder 3. The nut 74 is fixed to the second movable part 32 of the cylinder 3 and coaxial with the screw 71.

[0059] The nut 74 cooperates with the screw 71 such that a translation of the nut 74 in the direction determined SI of the actuation direction 33 causes the screw 71 to rotate in a direction determined S10 around the actuation direction 33, and another translation of the nut 74 in a different direction S2, opposite to the direction determined SI, causes the screw 71 to rotate in a different direction S20, opposite to the direction determined S10 around the actuation direction 33. In a first operating mode of the pitch locking device 7, during the movement of the cylinder 3 in nominal operation, for example when the cylinder 3 is actuated by the control circuit 5, the nut 74 translates freely and the screw 71 rotates freely.

[0060] The braking device 9 is capable of being actuated to act on the screw 71 so as to prevent the rotation of the screw 71 in the predetermined direction S10 of rotation around the actuation direction 33 of the cylinder 3. In other words, to trigger the pitch locking device 7, the braking system 9 is hydraulically triggered. In this second operating mode of the pitch locking device 7, the screw 71 is then blocked from rotating, and thus the nut 74, and therefore the cylinder 3, are blocked from translation. This ensures that the blade 100 does not orient itself around its pivot axis towards a so-called small-pitch position.

[0061] For example, the control circuit 5 is included in the pitch changing device 1. In this embodiment, the control circuit 5 is specific to the selective sending of the pressurized control fluid from the pressurized control fluid reservoir 51 to the braking device 9 to control the blocking of the rotation of the screw 71 around the direction 33 of actuation in the determined direction S10 of rotation when the braking device 9 is actuation.

[0062] In a third operating mode of the pitch locking device 7, actuating the screw 71 forces the blade 100 to feather. For To do this, the pitch changing device 1 further includes an electric motor 6 (or an electric actuator 6) mechanically coupled to the screw 71 of the pitch locking device 7.

[0063] An example of the mechanical attachment of the pitch locking device 7 to the electric motor 6 includes, for example, a support member, a return device, and a holding device. The support member can be movable in translation relative to the frame 2 along the actuation direction 33 between a free position corresponding to the first operating mode and a locking position corresponding to the second operating mode. The return device can move the support member towards the locking position, while the holding device is configured to maintain the support member in the free position under nominal conditions.

[0064] The electric motor 6 can be installed at the front of the pitch locking device 7 as illustrated. It has a control input 61 suitable for receiving a command from a computer, as will be detailed later.

[0065] The electric motor 6 is mechanically configured to rotate the screw 71 in the opposite direction of rotation S20 to the determined direction S10 of rotation to linearly move the nut 74 in the opposite direction S2 to the determined direction SI along the direction 33 of actuation, so as to move the second part 32 of the cylinder 3 in the opposite direction S2 to the determined direction SI of the direction 33 of actuation up to a first prescribed position 320 relative to the first part 31, when a prescribed actuation command C2 is present at the control input 61 of the electric motor 6.

[0066] The first prescribed position 320 of the second part 32 of the cylinder 3 corresponds to an angular position 112 of feathering of the blade 100 with respect to the first pivot axis 110.

[0067] The electric motor 6 thus allows the blade 100 to be returned to the feathering angular position 112. This may be the case, for example, when the actual angular position of the blade 100 around the first pivot axis 110 is unsatisfactory and / or does not correspond to the prescribed angular position ANG for the blade's pitch and / or when it is desired to stop the turbomachine T in flight and / or when a problem has been detected on the turbomachine T. This makes it possible to compensate for failures in the control circuit 5, particularly in the event of a rupture of the control fluid lines 52, or a malfunction of the hydraulic servovalve block 53 or the other rotary linkage interface 55 of the hydraulic circuit 5.The invention thus allows the elimination of common failure modes between the main system formed by the hydraulic circuit 5 allowing adjustment of the angular position of the blade 100 in nominal operation, and the auxiliary system formed by the electric motor. 6 and the link pitch locking device 7 allowing the blade 100 to be brought back into the feathering angular position 112, with less impact in terms of mass and integration.

[0068] According to one embodiment of the invention, the angular position 112 of feathering of the blade 100 represents the position in which the angle of attack of the gas flow (for example of the secondary air flow FS1 described below with reference to Figures 3 and 5) at the leading edge 113 of the blade 100 is minimal, as illustrated in [Fig.6], where this angular position 112 of feathering is symbolized by dashed lines ([Fig.6] being a cross-sectional view of the blade 100 perpendicular to the first pivot axis 110, the blade 100 being symbolized by a segment but being able of course to have a curvature from its leading edge 113 to its trailing edge 114). Thus, in this angular position 112 of feathering of the blade 100, the drag or aerodynamic disturbance generated by the blade 100 is minimal.The angular position 112 of the feathering of the blade 100 can be an extreme angular position of the blade 100 around the first pivot axis 110.

[0069] The actuation cylinder 3 is configured to modify, by moving the second part 32 linearly along the direction 33 of actuation relative to the first part 31 up to the setting position PI, the angular position ANG of the blade 100 around the first pivot axis 110 in an angular range having as its minimum (or extreme angular position) the feathering angular position 112 (i.e. ANG > 0, where ANG is the angular position ANG of the blade 100 taken relative to this feathering angular position 112).In Figures 1 and 2, the first prescribed position 320 corresponding to the angular position 112 of feathering of the blade 100 is symbolized by dashed lines as an example for the first end 36 of the second part 32 having been moved in the second direction S2 towards the first part 31 in this first prescribed position 320, and the angular position ANG of the blade 100 moving away from the angular position 112 of feathering corresponds to the setting position PI of the first end 36 of the second part 32, which is represented by solid lines in Figures 1 and 2 and in which the first end 36 of the second part 32 is further away from the first part 31 than in the first prescribed position 320.

[0070] Of course, it could be the opposite (referred to below as the opposite case): the first prescribed position 320 corresponding to the angular position 112 of the feathering of the blade 100 could be symbolized by dashed lines as an example for the second end 37 of the second part 32 having been moved in the first direction SI towards the first part 31 in this first prescribed position 320, and the angular position ANG of the blade 100 deviating from the angular position 112 The flagging position could correspond to the PI setting of the second end 37 of the second part 32, which is shown in solid lines in figures 1 and 2 and in which the second end 37 of the second part 32 is further away from the first part 31 than in the first prescribed position 320.

[0071] According to one embodiment of the invention, the screw 71 of the pitch locking device 7 has a thread 72. The thread 72 extends about a second axis 73 of rotation parallel to the direction 33 of actuation. The screw 71 is connected to a shaft 63 of the electric motor 6, such that when the shaft 63 of the electric motor 6 is rotated, the screw 71 is driven in rotation by the shaft 63 about the second axis 73 of rotation.

[0072] Preferably, the nut 74 of the pitch locking device 7 cooperates by screwing with the thread 72 of the screw 71. The nut 74 is locked in rotation relative to the screw 71. Thus, when the screw 71 is driven in rotation around the second axis 73 of rotation, it drives the nut 74 in translation along the second axis 73 of rotation.

[0073] Preferably, the pitch-changing device 1 comprises a linkage mechanism 8 connecting the nut 74 to the second part 32 of the cylinder 3 to convert the linear displacement, i.e., the translation S1, S2, of the nut 74 along the actuation direction 33 into the linear displacement of the second part 32 of the cylinder 3 along the actuation direction 33. The linkage mechanism 8 may be a rigid connection by one or more fixing parts 81 between the nut 74 and the second part 32 of the cylinder 3.

[0074] When the prescribed actuation command C2 is present at the control input 61 of the motor 6, the electric motor 6 rotates the shaft 63 in a determined direction 630 of rotation, typically in the opposite direction S20 of rotation to the determined direction S10 of rotation, which causes the nut 74 to move linearly along the second axis 73 of rotation to a second prescribed position 322 (represented by way of example in dashed lines in Figures 1 and 2) corresponding to the first prescribed position 320 of the second part 32 of the cylinder 3 relative to the first part 31, for example here in the opposite direction S2, opposite to the determined direction S1, as illustrated in Figures 1 and 2, which corresponds to the feathering of the blade 100.

[0075] Of course, in the case mentioned above, when the prescribed actuation command C2 is present at the control input 61 of the motor 6, the electric motor 6 could rotate the shaft 63 in a determined direction 630 of rotation, which causes the nut 74 to move linearly along the direction 33 of actuation to a second prescribed position (not shown in figures 1 and 2) corresponding to the first prescribed position 320 of the second part 32 of the cylinder 3 relative to the first part 31, in the first direction SI, which corresponds to the feathering of the blade 100.

[0076] The braking device 9 is configured to prevent the rotation of the screw 71 around the actuation direction 33 in the predetermined direction S10 of rotation, corresponding to a pivoting of the blade 100 towards a so-called small-pitch position, and to allow the rotation of the screw 71 around the actuation direction 33 in the opposite direction S20 of rotation, corresponding to a pivoting of the blade 100 towards a so-called large-pitch position, i.e., feathering, without engaging in order to allow the blades to return to the feathering position. In other words, the braking device 9 is capable of being actuated to act on the screw 71 so as to prevent the rotation of said screw 71 in the predetermined direction S10 of rotation around the actuation direction 33 of the cylinder 3.

[0077] In a first embodiment, the braking device 9 comprises a friction braking mechanism with a freewheel. In an alternative embodiment, the braking device 9 comprises a roller braking mechanism.

[0078] According to one embodiment of the invention, the locking device of the linkage pitch 7 may include rotating rollers between the screw 71 and the nut 74, the locking device of the linkage pitch 7 being said to be of the roller screw type.

[0079] According to another embodiment of the invention, the locking device of the linkage pitch 7 may comprise rotating balls between the screw 71 and the nut 74, the locking device of the linkage pitch 7 being said to be of the ball screw type.

[0080] According to one embodiment of the invention, the step change device 1 includes an electrical power supply 62, capable of supplying electrical energy to the electric motor 6.

[0081] Figures 1, 2, 3 and 5 describe examples of turbomachinery T on which the device 1 for changing the pitch of one (or more) variable pitch blade 100 can be provided.

[0082] The turbomachine T comprises a stator 210, a rotor 202 and a rotating part 203 comprising a fan 280. The fan 280 comprises the variable pitch blade(s) 100 and the device 1 for changing the pitch of the variable pitch blade(s) 100.

[0083] The rotating part 203, the blower 280 and the rotor 202 are mounted to rotate about a third axis AX of rotation relative to the stator 210.

[0084] The invention also relates to an aircraft A comprising the turbomachine(s) T, as illustrated in [Fig. 4]. The turbomachine(s) T is, for example, a propulsion system of the aircraft A, and may be, for example, a turbojet or a turboprop, or other.

[0085] The invention also relates to a method of controlling the angular pivoting position of the variable pitch blade(s) 100 of the turbomachine T around the first pivoting axis 110.

[0086] According to one embodiment of the invention, the aircraft A comprises a computer 301, which is connected to the control input 61 and is capable of generating the prescribed actuation command C2. Connection means are provided on the aircraft for sending the prescribed actuation command C2 to the control input 61 of the engine 6. The computer 301 may be or comprise one or more computers, one or more processors, one or more microprocessors, one or more control circuits, or other components. The computer 301 may have been programmed by a computer program comprising code instructions for implementing the method.

[0087] According to an embodiment of the invention, illustrated in [Fig. 1], the power supply 62, capable of supplying electrical energy to the electric motor 6, is provided in the rotating part 203 comprising the blower 280 or in the blower 280. Electrical wires 621, present in the rotating part 203 comprising the blower 280 or in the blower 280, connect the electric motor 6 to the power supply 62. The power supply 62 may be or include one (or more) electric battery or an alternating current source or a local electric generator. This embodiment allows the electrical energy to be supplied as close as possible to the electric motor 6, which has advantages from the point of view of the operational safety of the electric motor 6. A local electric generator in the rotating part 203 containing the blower 280 or in the blower 280 has the advantage of optimizing the mass of the system.

[0088] According to another embodiment of the invention, illustrated in [Fig.2], the power supply 62, capable of supplying electrical energy to the electric motor 6, is provided in the stator 210. A rotating link interface 206, allowing the electrical connection of the electric motor 6 to the power supply 62, is provided between the rotating part 203 and the stator 210. First electrical wires 622, present in the rotating part 203 comprising the blower 280 or in the blower 280, connect the electric motor 6 to the rotating link interface 206. Second electrical wires 623, present in the stator 210, connect the rotary link interface 206 to the power supply 62. The power supply 62 may be or include one (or more) electric battery or an alternating current power source or a local electric generator or a power supply from the turbomachine T.

[0089] The invention also relates to a method for adjusting the angular pivoting position of at least one variable-pitch blade 100 of the turbomachine T around of the first pivot axis 110, which is described below with reference to figures 1, 2, 6 and 7.

[0090] This process comprises the following steps.

[0091] During the first step El, the control unit 301 sends a first command Cl to the control circuit 5 to send the pressurized control fluid from the pressurized control fluid reservoir 51 to either the first chamber 34 or the second chamber 35, causing the linear movement of the second part 32 of the cylinder 3 along the actuation direction 33 relative to the first part 31 to the setting position PI corresponding to the angular position ANG of the blade 100 around the first pivot axis 110. This angular position ANG is specified in the control unit 301 and corresponds, for example, to a calculated operating point of the turbomachine T. The control unit 301 is connected by electrical conductors 302 to a control input 56 of the hydraulic circuit 5 to send it the first command Cl.

[0092] In the embodiment described in Figures 1 and 2, the linear displacement of the second part 32 of the cylinder 3 along the actuation direction 33 relative to the first part 31, up to the adjustment position PI corresponding to the angular position ANG of the blade 100 around the first pivot axis 110 during the first step 11, causes the nut 74 to move along the second axis 73 of rotation, which rotates the screw 71 and the shaft 63 freely around the second axis 73 of rotation. This corresponds to the first operating mode of the pitch locking device 7.

[0093] During a second step E2 subsequent to the first step E1, the computer 301 sends the prescribed actuation command C2 to the control input 61 of the electric motor 6, to rotate the screw 71 in the opposite direction of rotation S20, the opposite of the determined direction S10 of rotation, in order to linearly move the nut 74 in the opposite direction S2, the opposite of the determined direction SI, along the actuation direction 33, so as to linearly move the second part 32 of the cylinder 3 in the opposite direction S2 to the determined direction SI of the actuation direction 33, to the first prescribed position 320 relative to the first part 31, to cause the blade 100 to pivot relative to the first pivot axis 110, from the angular position ANG of the setting to the angular position 112 of the feathering of the blade 100 corresponding to the first prescribed position. 320. This corresponds to the third operating mode of the step locking device 7.

[0094] According to one embodiment of the invention, the computer 301 is connected by electrical conductors 303 to the control input 61 of the electric motor 6 to send it the prescribed actuation command C2. The computer 301 can to be fixed relative to the stator 210, the electrical conductors 303 can pass through a rotating link interface 207, which allows the electrical connection of the electric motor 6 to the computer 301 and which is provided between the rotating part 203 and the stator 210, this interface 207 being able to be the interface 206 in [Fig.2].

[0095] According to another embodiment of the invention, not shown, the computer 301 is connected by wireless communication means to the control input 61 of the electric motor 6 to send it the prescribed actuation command C2. These wireless communication means comprise a transmitter with a transmitting antenna, which is connected by electrical conductors to the computer 301, and a receiver with a receiving antenna, which is connected by electrical conductors to the control input 61 of the electric motor 6. The transmitter with a transmitting antenna is located away from the receiver with a receiving antenna and is capable of transmitting the prescribed actuation command C2 to the receiver with a receiving antenna by free waves (for example, by Wi-Fi or radio frequency, or other means).

[0096] According to one embodiment of the invention, the pitch change device 1 includes a sensor 304 for measuring the actual angular position of the blade 100 around the first pivot axis 110. The sensor 304 is connected to the computer 301 and provides the computer 301 sensor 304 with the actual angular position of the blade 100, having been measured by the sensor 304. The second step E2 includes a substep E21, during which the computer 301 determines whether the actual angular position of the blade 100, having been measured by the sensor 304, is equal to the prescribed angular position ANG of the blade 100, having been commanded by the first command CL

[0097] In the case where the computer 301 determines that the actual angular position of the blade 100, having been measured by the sensor 304, is equal to the prescribed angular position ANG of the blade 100, having been commanded by the first command Cl, the second step E2 is not carried out.

[0098] If the computer 301 determines that the actual angular position of the blade 100, as measured by the sensor 304, is not equal to the prescribed angular position ANG of the blade 100, as commanded by the first command Cl, the second step E2 is performed to bring the blade 100 to the feathering angular position 112 via the electric motor 6. This case corresponds, for example, to a disturbance affecting the blade 100, causing it to adopt an angular position different from the prescribed angular position ANG calculated for the first command CL. In this case, the actual operating point of the turbomachine T may be degraded compared to the calculated operating point of the turbomachine T. Step E2 may correspond to a shutdown of the turbomachine T.

[0099] According to one embodiment of the invention, the prescribed actuation command C2 can be carried out by sending an electric current through the power supply 62 to the electric motor 6. The power supply 62 can in this case be controlled by the computer 301. The absence of the prescribed actuation command C2 corresponds in this case to the absence of sending an electric current through the power supply 62 to the electric motor 6.

[0100] According to an embodiment of the invention, illustrated in figures 1 and 2, the hydraulic circuit 5 can be provided in the stator 210. In this case, the control fluid lines 52 of the hydraulic circuit 5 are connected via another rotating link interface 55 to the first chamber 34 and to the second chamber 35, to ensure the transfer of the control fluid between on the one hand the control fluid lines 52 of the hydraulic circuit 5 and on the other hand the first chamber 34 and the second chamber 35.

[0101] A first example of an aeronautical turbomachine T is described in more detail below with reference to [Fig.3], in which the pitch change device 1 can be used to adjust an angular pivoting position of one (or more) variable pitch blade 100 of the turbomachine T according to the invention.

[0102] In the embodiment of [Fig.3], the turbomachine T is shrouded (presence of a fan housing 300 around the fan 280 and presence of a shroud 200 around the housing 360).

[0103] As is known, the turbomachine T shown in [Fig.3] is intended to be installed on an aircraft A to propel it through the air, as shown in [Fig.4],

[0104] The turbomachine T extends around the axis AX or axial direction AX (or first longitudinal direction AX mentioned below) oriented from upstream to downstream. In [Fig. 3], the terms "upstream", respectively "downstream" or "front", respectively "back", or "left", respectively "right", or "axially" are taken along the general direction of the gases flowing in the turbomachine along the axis AX. The direction from the inside to the outside is the radial direction DR (or third height direction DR mentioned below) from the axis AX.

[0105] The turbomachine T is, for example, a twin-spool turbomachine. The turbomachine T comprises a first stage consisting of a rotary fan 280 and a gas generator 130, located downstream of the rotary fan 280. Central to the turbomachine, the gas generator 130 comprises, from upstream to downstream in the direction of gas flow, a low-pressure compressor CBP1, a high-pressure compressor CHP1, a combustion chamber 160, a high-pressure turbine THP1, and a low-pressure turbine TBP1, which define a primary gas flow FPL

[0106] The pitch changing device 1 is provided for adjusting an angular pivoting position of at least one variable pitch blade 100 of the turbomachine T, which is rotating about the axis AX, such as for example at least one (or several or all) of the blades 100 (or vanes 100) of the blower 280 (or of the rotating part 203) in [Fig.3].

[0107] The rotary fan 280 comprises variable-pitch blades 100, which extend radially outwards from a rotary fan hub 250 and are distributed on this hub around the axis of rotation AX, the hub 250 being upstream of the housing 360. The housing 360 forms the stator 210 of the turbomachine T. The rotary hub 250 of the fan 280 and the blades 100 are capable of rotating about the axis AX. The rotary fan blades 100 are externally surrounded by the fan housing 300. The first pivot axis 110 of each variable-pitch blade 100 can be radial in the direction DR.

[0108] The angular position of each blade 100 of the rotary blower 280 around its first pivot axis 110 relative to the rotary blower hub 250 (forming the frame 2) can be adjusted by the pitch changing device 1 according to the invention, provided in the blower 280.

[0109] The turbomachine T includes downstream of the fan hub 250 and in the casing 360 a motor assembly 500 enabling the fan hub 250 and therefore the fan blades 100 to rotate around the axis AX of rotation.

[0110] The turbomachine T has an upstream inlet end 290 located upstream of the fan 280, and a downstream exhaust end 311. The casing 360 of the turbomachine T delimits a primary channel in which the primary flow FP1 flows which passes downstream of the fan 280 through the low pressure compressor CBP1, the high pressure compressor CHP1, the high pressure turbine THP1 and the low pressure turbine TBP1.

[0111] The engine assembly 500 comprises in the casing 360, from upstream to downstream in the direction of gas flow, a casing 361 of the low pressure compressor CBP1, an intermediate casing 260, which is interposed between the low pressure compressor CBP1 and the high pressure compressor CHP1, a casing 362 of the high pressure compressor CHP1, a casing 363 of the high pressure turbine THP1 and a casing 190 of the low pressure turbine TBP1.

[0112] The low pressure compressor CBP1 and the high pressure compressor CHP1 can each comprise one or more stages, each stage being formed by a set of fixed blades (or stator blades) and a set of rotating blades forming part of the rotor 202 (or rotor blades).

[0113] The fixed vanes 101 of the low-pressure compressor CBP1 are fixed to the casing 361. The rotating vanes 102 (forming part of the rotor 202) of the low-pressure compressor CBP1 are fixed to a first rotating transmission shaft 410.

[0114] The fixed blades 103 of the high-pressure compressor CHP1 are fixed to the casing 362. The rotating blades 104 (forming part of the rotor 202) of the high-pressure compressor CHP1 are fixed to a second rotating transmission shaft 400.

[0115] The high pressure turbine THP1 and the low pressure turbine TBP1 can each comprise one or more stages, each stage being formed by a set of fixed blades (or stator blades) and a set of rotating blades forming part of the rotor 202 (or rotor blades).

[0116] The fixed blades 105 of the high-pressure turbine THP1 are fixed to the casing 363. The rotating blades 106 (forming part of the rotor 202) of the high-pressure turbine THP1 are fixed to the second rotating transmission shaft 400.

[0117] The fixed blades 107 of the low-pressure turbine TBP1 are fixed to the casing 190. The rotating blades 108 (forming part of the rotor 202) of the low-pressure turbine TBP1 are fixed to the first rotating transmission shaft 410.

[0118] The rotating blades 108 of the low-pressure turbine TBP1 drive the rotating blades 102 of the low-pressure compressor CBP1 in rotation around the axis AX under the effect of the thrust of the gases from the combustion chamber 160. The rotating blades 106 of the high-pressure turbine THP1 drive the rotating blades 104 of the high-pressure compressor CHP1 in rotation around the axis AX under the effect of the thrust of the gases from the combustion chamber 160.

[0119] The blades 100 of the blower 280 are upstream of the blades 101, 102, 103, 104, 105, 106, 107 and 108 and are of a different shape from them.

[0120] In operation, air flows through the rotary fan 280 and a first portion FP1 (primary flow FP1) of the airflow is routed through the low-pressure compressor CBP1 and the high-pressure compressor CHP1, where the airflow is compressed and sent to the combustion chamber 160. The hot combustion products (not shown in the figures) from the combustion chamber 160 are used to drive the turbines THP1 and TBP1 and thus produce the thrust of the turbomachine T. The turbomachine T also includes a secondary duct 390 which is used to route a secondary flow FS1 of the airflow discharged from the rotary fan 280 around the casing 360. More specifically, the secondary duct 390 extends between an inner wall 201 of the shroud 200 or nacelle 200 and the casing 360 surrounding the gas generator 130, the the 300 blower housing being the upstream part of this 200 fairing or 200 nacelle.

[0121] Arms 340 connect the intermediate housing 260 to the inner wall 201 of the fairing 200 in the secondary vein 390 of the secondary flow FS1. A fixing arm 364 external or an external means of attachment connects the fairing 200 to the aircraft A, as shown in [Fig.4].

[0122] Of course, the pitch-changing device 1 could also be provided for adjusting the angular pivot position of at least one other variable-pitch blade 100 of the turbomachine T, which is rotatable about the axis AX, such as, for example, at least one (or more or all) of the rotating blades 102 of the low-pressure compressor CBP1 and / or at least one (or more or all) of the rotating blades 104 of the high-pressure compressor CHP1 and / or at least one (or more or all) of the rotating blades 106 of the high-pressure turbine THP1 and / or at least one (or more or all) of the rotating blades 108 of the low-pressure turbine TBP1. In this case, the first pivot axis 110 of this variable-pitch blade 100 can be radial in the direction DR.

[0123] A second example of an aeronautical turbomachine T is described in more detail below with reference to [Fig.5], in which the pitch change device 1 can be used to adjust an angular pivoting position of at least one variable pitch blade 100 of the turbomachine T according to the invention.

[0124] The pitch changing device 1 is provided for adjusting an angular pivoting position of at least one variable pitch blade 100 of the turbomachine T, which is rotating about the axis AX, such as for example at least one (or several or all) of the blades 100 (or vanes 100) of the blower 280 (or of the rotating part 203) in [Fig.5].

[0125] The rotary fan 280 includes the variable-pitch blades 100, which extend radially outwards from the rotary fan hub 250 and are distributed on it around the axis of rotation AX, the hub 250 being upstream of the housing 360. The housing 360 forms the stator 210 of the turbomachine T. The rotary hub 250 of the fan 280 and the blades 100 are able to rotate around the axis AX.

[0126] In the embodiment of [Fig.5], the turbomachine T is uncased (absence of a casing around the fan 280 and absence of a fairing around the casing 360).

[0127] The angular position of each blade 100 of the rotary blower 280 around its first pivot axis 110 relative to the rotary blower hub 250 can be adjusted by the pitch changing device 1 according to the invention, provided in the blower 280.

[0128] This second example of [Fig.5] is analogous to the first example described above with reference to Figures 3 and 4, with the differences described below.

[0129] The blower hub 250 has a downstream hub portion 253, which is surrounded by an inner surface 402 of an upstream portion 403 of the housing 360 and which protrudes from the upstream portion 403 of the housing 360.

[0130] The turbomachine T further comprises secondary flow straightener blades 150, the mounting side 11 of which is movably mounted or fixed on an outer wall 404 of the upstream part 403 of the casing 360. The secondary flow straightener blades 150 are located downstream with respect to the fan blades 100 280. The straightener blades 150 are therefore placed in the secondary airflow FS1, which is created downstream of the fan blades 100 280 around the outer wall 404 of the casing 360, when the fan blades 100 280 are rotated about the axis AX.

[0131] The aeronautical turbomachine T is uncased, which means that the stator blade 150 is fixed or mounted only by its mounting side 151 (or blade foot 151) on the outer wall 404 of the upstream part 403 of the casing 360. The head 152 of the stator blade 150, which is located at the end of the blade 150 away from its mounting side 151 along the radial DR direction, is left bare in the secondary airflow FS1, without being mounted or fixed to a casing, no casing or nacelle surrounding the stator blades 150 and the casing 360.

[0132] The motor assembly 500 in the casing 360 is analogous to the first example described above with reference to [Fig.3] and has not been shown in [Fig.5].

[0133] The engine assembly 500 comprises in the casing 360, from upstream to downstream in the direction of gas flow, the low pressure compressor, the high pressure compressor, the combustion chamber, the high pressure turbine and the low pressure turbine, which delimit the primary gas flow in the casing 360 from an air inlet 405, which is located between the upstream part 403 of the casing 360 and the blower hub 250 and downstream of the blower blades 100 280.

[0134] In operation, air flows through the rotary fan 280, and a first portion FP1 (primary flow FP1) of the airflow is routed through the low-pressure compressor and the high-pressure compressor, where the primary flow FP1 is compressed and sent to the combustion chamber. The hot combustion products from the combustion chamber are used to drive the high-pressure turbine and the low-pressure turbine, thus producing the thrust of the turbomachine T, and are discharged through a nozzle 368 located at the downstream end of the downstream portion 407 of the casing 360, which is located downstream of the upstream portion 403 of the casing 360. The secondary airflow FS1 is discharged from the rotary fan 280 around the casing 360 from upstream to downstream.The straightener blade 150 has a shape configured to concentrate the secondary airflow FS1 against the outer surface 406 of the downstream part 407 of the housing 360, located downstream of the outer wall 404 of the upstream part 403 of the housing 360. An external mounting arm 364 or external mounting means connects the housing 360 to the aircraft A, as shown in [Fig.4].

[0135] Of course, the embodiments, features, possibilities and examples described above can be combined with each other or selected independently of each other.

Claims

1. Demands Pitch changing device (1) for adjusting the angular pivoting position of at least one variable-pitch turbomachine blade (100) about a first pivoting axis (110) of the blade (100), the device (1) comprising: a frame (2) fixed relative to the first pivot axis (110), an actuating cylinder (3), having a first part (31) fixed relative to the frame (2) and a second part (32) linearly movable along a direction (33) of actuating the cylinder (3) relative to the first part (31), a linkage mechanism (4) connecting the second part (32) of the cylinder (3) to the blade (100) to convert a linear displacement of the second part (32) of the cylinder (3) along the direction (33) of actuation into a rotation of the blade (100) around the first pivot axis (110), a step locking device (7) adapted to immobilize the linear displacement of the second part (32) of the cylinder (3) relative to the first fixed part (31) in a determined direction (SI) of the direction (33) of actuation of the cylinder (3), the step locking device (7) comprising: a screw (71) mounted to rotate freely around the direction (33) of actuation of the cylinder (3), a nut (74) integral with the second part (32) of the cylinder (3) and coaxial with the screw (71), the nut (74) cooperating with the screw (71) such that a translation of the nut (74) along the determined direction (SI) of the actuation direction (33) causes the screw (71) to rotate in a determined direction (S10) of rotation around the actuation direction (33), and another translation of the nut (74) along another direction (S2) opposite to the determined direction (SI) causes the screw (71) to rotate in another direction (S20) opposite to the determined direction (S10) of rotation around the actuation direction (33), and a braking device (9), which is capable of being actuated to act on the screw (71) so as to immobilize the rotation of said screw (71) in the determined direction (S 10) of rotation around the direction of actuation (33) of the cylinder (3); characterized in that The device (1) comprises an electric motor (6) mechanically coupled to the screw (71) of the pitch locking device (7). The electric motor (6) has a control input (61). The electric motor (6) is configured to rotate the screw (71) in the opposite direction (S20) to the determined direction (S10) of rotation in order to linearly move the nut (74) in the opposite direction (S2) to the determined direction (SI) along the actuation direction (33), so as to move the second part (32) of the cylinder (3) in the opposite direction (S2) to the determined direction (SI) of the actuation direction (33) to a first prescribed position (320) relative to the first part (31). When a prescribed actuation command (C2) is present at the control input (61), the first prescribed position (320) corresponding to an angular position (112) of feathering. of the blade (100) relative to the first pivot axis (110).

2. Device according to claim 1, characterized in that the angular position (112) of feathering of the blade (100) corresponds to the angular position in which the angle of attack of the airflow to a leading edge of the blade is minimal.

3. A device according to any one of the preceding claims, characterized in that the screw (71) of the pitch locking device (7) has a thread (72) about a second axis (73) of rotation parallel to the direction (33) of actuation and is connected to a shaft of the electric motor (6) so that said screw (71) is driven in rotation about the second axis (73) of rotation when the shaft (63) of the electric motor (6) is rotated.

4. Device according to claim 3, characterized in that the nut (74) of the pitch locking device (7) cooperates by screwing with the thread (72) of the screw (71) and is locked in rotation relative to the screw (71), to drive in translation the nut (74) along the second axis (73) of rotation when the screw (71) is driven in rotation around the second axis (73) of rotation.

5. A device according to any one of the preceding claims, characterized in that the device comprises a linking mechanism (8) connecting the nut (74) to the second part (32) of the cylinder (3) for converting the translation (S1, S2) of said nut (74) along the direction (33) of actuation into linear displacement of the second part (32) of the cylinder (3) along the direction (33) of actuation.

6. Device according to any one of the preceding claims, characterized in that the electric motor (6) is configured to rotate the shaft (63) in the opposite direction of rotation (S20) to the determined direction (S10) of rotation to linearly move the nut (74) in the opposite direction (S2) to the determined direction (SI) of the direction (33) of actuation to a second prescribed position (322) corresponding to the first prescribed position (320) of the second part (32) of the cylinder (3) relative to the first part (31), when the prescribed actuation command (C2) is present at the control input (61).

7. Device according to any one of claims 1 to 6, characterized in that the pitch locking device (7) comprises rotating rollers between the screw (71) and the nut (74).

8. Device according to any one of claims 1 to 6, characterized in that the pitch locking device (7) comprises rotating balls between the screw (71) and the nut (74).

9. Device according to any one of the preceding claims, wherein the second part (32) of the cylinder (3) delimits a first chamber (34) and a second chamber (35) which are separated from each other in a manner sealed against a control fluid by the first part (31) of the cylinder (3).

10. Device according to claim 9, further comprising a control circuit (5) for the selective sending of the pressurized control fluid from a pressurized control fluid reservoir (51) either to the first chamber (34) to control the linear movement of the second part (32) of the cylinder (3) in the other direction (S2) opposite to the determined direction (SI) along the direction (33) of actuation relative to the first part (31), or to the second chamber (35) to control the linear movement of the second part (32) of the cylinder (3) in the determined direction (SI) along the direction (33) of actuation relative to the first part (31).

11. Device according to claim 10, characterized in that the control circuit (5) is adapted for the selective delivery of pressurized control fluid from the pressurized control fluid reservoir (51) to the braking device (9) to control the locking of the rotation of the screw (71) around the direction (33) of actuation in the determined direction (S 10) of rotation during the actuation of the braking device (9).

12. Device according to any one of the preceding claims, characterized in that the braking device (9), which is capable of being actuated to act on the screw (71) so as to immobilize the rotation of said screw (71) in the determined direction (S 10) of rotation around the direction of actuation (33) of the cylinder (3) comprises a friction braking mechanism.

13. Device according to any one of claims 1 to 11, characterized in that the braking device, which is capable of being actuated to act on the screw (71) so as to immobilize the rotation of said screw (71) in the determined direction (S 10) of rotation around the direction of actuation (33) of the cylinder (3) comprises a braking mechanism by means of a roller system.

14. Device according to any one of the preceding claims, characterized in that the step change device (1) comprises an electrical power supply (62), capable of supplying electrical energy to the electric motor (6).

15. Turbomachine (T), comprising a stator (210), a rotor (202) and a rotating part (203) comprising a blower (280), the blower (280) comprising at least one variable pitch blade (100) and a pitch changing device (1) according to any one of the preceding claims, the rotating part (203) and the rotor (202) being mounted to rotate about a third axis (AX) of rotation relative to the stator (210).

16. Turbomachine (T) according to claim 15, characterized in that an electrical power supply (62), capable of supplying electrical energy to the electric motor (6), is provided in the rotating part (203) comprising the blower (280).

17. Turbomachine (T) according to claim 15 characterized in that an electrical power supply (62), suitable for supplying electrical energy to the electric motor (6), is provided in the stator (210), a rotating link interface (206), allowing the electrical connection of the electric motor (6) to the electrical power supply (62), being provided between the rotating part (203) and the stator (210).

18. Aircraft (A) comprising at least one turbomachine (T) according to any one of claims 15 to 17 and a computer (301),

19. which is connected to the control input (61) and which is capable of generating the prescribed actuation command (C2) to send the prescribed actuation command (C2) to the control input (61). Method for adjusting the angular pivoting position of at least one variable-pitch blade (100) of the turbomachine (T) of the aircraft (A) according to claim 18 about the first pivoting axis (110), the pitch-changing device (1) further comprising a control circuit (5) for selectively sending pressurized control fluid from a pressurized control fluid reservoir (51) either to the first chamber (34) to control the linear displacement of the second part (32) of the cylinder (3) in the opposite direction (S2) to the determined direction (SI) along the actuation direction (33) relative to the first part (31), or to the second chamber (35) to control the linear displacement of the second part (32) of the cylinder (3) in the determined direction (SI) along the actuation direction (33) relative to the first part (31), the method comprising the following steps: The computer (301) sends a first command (C1) to the control circuit (5) to send pressurized control fluid from the pressurized control fluid reservoir (51) to either the first chamber (34) or the second chamber (35), causing linear movement of the second part (32) of the cylinder (3) along the actuation direction (33) relative to the first part (31) to an adjustment position (PI) corresponding to a prescribed angular position (ANG) of the blade (100) around the first pivot axis (110). The computer (301) then sends the prescribed actuation command (C2) to the control input (61) of the electric motor (6), to rotate the screw (71) in the opposite direction (S20) to the determined direction (S10) of rotation, thus linearly moving the nut (74) in the opposite direction. (S2) inverse of the determined direction (SI) along the direction (33) of actuation,so as to linearly move the second part (32) of the cylinder (3) in the opposite direction (S2) to the determined direction (SI) of the actuation direction (33) to the first prescribed position (320) by, in relation to the first part (31), to cause the pivoting of the blade (100) with respect to the first pivot axis (110), from the angular position (ANG) of the setting to the angular position (112) of the feathering of the blade (100) corresponding to the first prescribed position (320).

Images