Turbine engine comprising an actuator and aircraft comprising such a turbine engine, and corresponding actuation method

Abstract

The invention relates to an actuator (6) which comprises a cylinder (8) comprising a rod (10) provided with a piston (12) defining first and second chambers (14, 16), first and second fluid lines (22, 24) fluidly connected to the first chamber (14), and a resilient return means (26) configured to exert a force on the piston (12), wherein the first fluid line (22) comprises a calibrated port (28), and the actuator (6) comprises a servo-valve (30) fluidly connected to the second fluid line (24), a cross-sectional area of the servo-valve (30) being greater than or equal to ten times a cross-sectional area of the calibrated port (28), or the head loss in the first fluid line (22) being greater than or equal to ten times the head loss in the second fluid line (24).

Description

[0001] DESCRIPTION

[0002] TITLE: TURBOMACHINE COMPRISING AN ACTUATOR AND AIRCRAFT COMPRISING SUCH A TURBOMACHINE, AND CORRESPONDING ACTUATION METHOD

[0003] Technical field

[0004] The present invention relates to the technical field of fast actuators.

[0005] In particular, the present invention relates to an actuator, a turbomachine and an aircraft containing such an actuator, as well as a corresponding actuation method.

[0006] Previous techniques

[0007] Some applications, especially aerial ones, require actuators with fast movement dynamics, which some actuators do not have.

[0008] For example, an electropneumatic actuator has slower motion dynamics than a fuel actuator.

[0009] A fuel actuator is, for example, a hydraulic actuator controlled by pressure taken from a fuel circuit supplying the combustion of a gas turbine.

[0010] Implementing a fuel actuator on a machine requires a complex machine architecture. The fuel requirement of the fuel actuator can cause the machine's fuel system to be oversized, which can lead to leaks or a syringe effect.

[0011] The machine can create an environment of high temperatures and intense vibrations making actuator integration difficult and possibly preventing the implementation of certain types of actuators, such as an electric actuator.

[0012] Statement of the invention

[0013] The present invention therefore aims to overcome all or part of the aforementioned drawbacks and to propose an actuator with rapid movement dynamics compatible with the thermal and vibration conditions of an aircraft.The invention relates to an actuator comprising a cylinder comprising a rod provided with a piston at least partially delimiting a first and a second chamber, the actuator comprising a first and a second fluid conduit fluidly connected to the first chamber, an elastic means for returning to a predetermined position arranged in one of the first and second chambers and configured to exert a force on the piston, the first fluid conduit comprising a calibrated orifice, the actuator comprising a two-way servovalve fluidly connected to the second fluid conduit, a passage section of the servovalve being greater than or equal to ten times a passage section of the calibrated orifice or the pressure drop in the first fluid conduit being greater than or equal to ten times the pressure drop in the second fluid conduit.

[0014] The large passage section of the servovalve compared to the reduced passage section of the calibrated orifice makes it possible to obtain significant dynamics of a movement of the piston in a first direction, in particular during the return of the elastic means to the predetermined position, and lower dynamics of another movement of the piston in a second direction opposite to the first direction.

[0015] The use of the two-way servo valve ensures a simple actuator design.

[0016] The actuator design is compatible with aircraft thermal and vibration conditions.

[0017] The actuator may include a common conduit opening into the first chamber, the first and second fluid conduits being fluidically connected to the common conduit.

[0018] The two-way servo valve may include an electromagnetic control.

[0019] In one embodiment, the two-way servovalve is configured to have at least one on state such that fluid can flow in the second fluid line through the two-way servovalve and a off state such that fluid cannot flow in the second fluid line through the two-way servovalve.

[0020] The two-way servovalve may include a proportional control configured to position the piston in an intermediate position of a piston stroke.

[0021] The piston may be associated with a sealed rolling membrane to sealably separate the first and second chambers.

[0022] The passage section of the two-way servovalve can be greater than twenty times the passage section of the calibrated orifice.

[0023] The invention also relates to a turbomachine comprising an actuator as defined previously, a first source of fluid and a second source of fluid, one of the first and second fluid lines being configured to take a first fluid from the first source of fluid, the other fluid line being configured to take a second fluid from the second source of fluid, the pressure of the first fluid being greater than the pressure of the second fluid.

[0024] The first fluid source may comprise a compressor, the second fluid comprising air under atmospheric pressure.

[0025] The present invention also relates to an aircraft comprising an actuator as defined previously and / or a turbomachine as defined previously.

[0026] The present invention also relates to an actuation method implemented by an actuator as defined above or by a turbomachine as defined above, or by an actuator included in an aircraft as defined above, comprising the following steps: changing the state of the two-way servovalve so that the two-way servovalve is in a first state; moving the piston and the rod in a first direction at a first speed, said movement being due to a first difference in forces acting on the piston depending at least on the pressure in the first chamber and the force exerted by the elastic return means on the piston; and / or changing the state of the two-way servovalve so that the two-way servovalve is in a second state;and displacement of the piston and the rod in a second direction opposite to the first direction at a second speed different from the first speed, said displacement being due to a second difference in forces acting on the piston depending at least on the pressure in the first chamber and on the force exerted by the elastic return means on the piston.;

[0027] Brief description of the drawings

[0028] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example and made with reference to the appended drawings in which:

[0029] [Fig 1] schematically illustrates an aircraft comprising a turbomachine and an actuator according to the invention;

[0030] [Fig 2] schematically illustrates an actuator according to a first embodiment of the invention;

[0031] [Fig 3] schematically illustrates an actuator according to a second embodiment of the invention; and

[0032] [Fig 4] schematically illustrates an actuation method according to the invention.

[0033] Detailed description

[0034] Figure 1 schematically represents an aircraft 2, for example a helicopter or an airplane, comprising a booster turbomachine 4 such as, for example, the turbomachine of an auxiliary power unit or APU (Auxiliary Power Unit) in English terminology. Such a booster turbomachine 4 is distinct from the turbomachines dedicated to the propulsion of the aircraft, but like the latter it comprises moving members requiring actuation. These moving members, also called “variable geometries”, are for example inlet guide vanes or IGV (Inlet Guide Vane) in English terminology and / or an anti-surge valve. The aircraft 2 comprises, for example, a start valve and / or an auxiliary power unit for regulating pressurized air, requiring actuation. Consequently, the aircraft comprises at least one actuator 6.The use of an actuator 6 according to the invention is however not limited to the scope of a booster turbomachine 4, the actuator 6 can be implemented in a turbomachine of a main engine (i.e. dedicated to the propulsion of the aircraft) or even in an air system of the aircraft (air conditioning, defrosting, etc.) taking pressurized air from a turbomachine.

[0035] Figure 2 schematically represents a first embodiment of the actuator 6.

[0036] The actuator 6 comprises a cylinder 8 comprising a rod 10 provided with a piston 12. The piston 12 delimits within the cylinder 8 a first chamber 14 and a second chamber 16. The rod 10 is configured to perform a longitudinal movement in the cylinder 8. In the example shown, the rod 10 extends from the piston 12 into the second chamber 16 and passes through a first wall 18 of the cylinder 8. Alternatively, the rod 10 could extend from the piston 12 into the first chamber 14 and pass through a second wall 20 of the cylinder 8 opposite the first wall 18, the cylinder 8 then comprising a sealed element to guarantee the sealing of the first chamber 14 at the level of the second wall 20.

[0037] The cylinder 8 comprises a first fluid line 22 fluidly connected to the first chamber 14, the first fluid line 22 here being directly connected to the first chamber 14. The cylinder 8 comprises a second fluid line 24 fluidly connected to the first chamber 14, the second fluid line 24 here being directly connected to the first chamber 14.

[0038] The cylinder 8 comprises an elastic return means 26 in a predetermined position arranged in the second chamber 16 and capable of exerting a force on the piston 12, the elastic return means 26 comprising for example a helical spring surrounding the rod 10 so as to exert a force longitudinally on the piston 12 during the longitudinal movement of the piston 12. As a variant, the elastic return means 26 can be arranged in the first chamber 14.

[0039] The first and second fluid conduits 22, 24 are, for example, tubular pipes of constant section.

[0040] The first fluid line 22 comprises a calibrated orifice 28 comprising, for example, a restriction orifice locally reducing the cross-section of the first fluid line 22 so that the first fluid line 22 locally has a cross-section smaller than a constant cross-section of the second fluid line 24. The calibrated orifice 28 is in particular capable of modifying the pressure and / or the flow rate of a fluid circulating in the first fluid line 22, said fluid preferably being gaseous. The actuator 6 comprises a two-way servovalve 30 fluidically connected to the second fluid line 24.In a particular embodiment, the two-way servovalve 30 is connected directly to the second fluid line 24 so that a fluid flowing from a first end 32 of the second fluid line 24 to a second end 34 of the second fluid line 24 necessarily flows through the two-way servovalve 30, the first end 32 here being directly connected to the first chamber 14.

[0041] The circulation of a fluid through the first fluid line 22 is limited by a passage section of the calibrated orifice 28, the circulation of a fluid through the second fluid line 24 being limited by a passage section of the two-way servovalve 30, the passage section of the two-way servovalve 30 being greater than or equal to ten times a passage section of the calibrated orifice. Alternatively, the ratio of the two passage sections may be less than ten provided that the pressure drop in the first fluid line 22 is greater than or equal to ten times the pressure drop in the second fluid line 24.

[0042] Preferably, the two-way servovalve 30 comprises an electromagnetic actuator 36. The electromagnetic actuator 36 is compact, requires low electrical operating power and offers high responsiveness. Alternatively, the two-way servovalve 30 may comprise a hydraulic or electric actuator.

[0043] In this first embodiment, the two-way servovalve 30 comprises only a first state and a second state. For example, the first state corresponds to a passing state of the two-way servovalve 30, i.e. a state in which a fluid can flow through the two-way servovalve 30 and therefore through the second fluid line 24, the second state corresponding to a blocking state of the two-way servovalve 30, i.e. a state in which a fluid cannot flow through the two-way servovalve 30 and therefore through the second fluid line 24.

[0044] Advantageously, the piston 12 comprises a sealed element configured to prevent a circulation of fluid between the first and second chambers 14, 16. In the example shown, the actuator 6 comprises a sealed rolling membrane 38 associated with the piston 12, the piston 12 and the rolling membrane 38 delimiting the first and second chambers 14, 16 and preventing a transfer of fluid between the first and second chambers 14, 16.

[0045] The actuator 6 comprises a first fluid source 40 and a second fluid source 42.

[0046] The first fluid line 22 is capable of taking a first fluid under a first pressure. The first fluid is for example air under a high pressure, in particular air under a pressure at least twice as high as air at atmospheric pressure. The first fluid is for example taken from the first fluid source 40. Preferably, the first fluid source 40 is located close to the actuator 6 so as to reduce the length of the first fluid line 22. In the example shown, the first fluid is taken from a compressor, not shown, of a propulsion engine of the aircraft 2. Alternatively, the first fluid can be taken from another fluid source of the propulsion engine, for example taken from a fan. Advantageously, the calibrated orifice 28 of the first fluid line 22 allows the actuator 6 to be very little disruptive to the first fluid source 40.The first fluid line 22 then draws a small quantity of fluid from the first fluid source 40, the energy requirement of the first fluid source 40 being slightly increased.

[0047] The second fluid line 24 is capable of drawing a second fluid under a second pressure. The second fluid is for example drawn from the second fluid source 42. In the example shown, the second fluid source 42 is the atmosphere, the second fluid being the air in which the aircraft 2 is moving, the second fluid therefore being under a pressure lower than the pressure of the first fluid. The second fluid line 24 then discharges the fluid coming from the first chamber 14 and from the first fluid line 22 to the atmosphere.

[0048] When the two-way servovalve 30 is in the blocking state, the flow rate of fluid circulating in the second fluid line 24 is zero or very low, only the first fluid line 22 is able to inject pressurized fluid into the first chamber 14. The pressure in the first chamber 14 increases when the first fluid is injected into the first chamber 14, thus exerting a force on the piston 12 against the elastic return means 26 and an external force of the member controlled by the actuator 6. If the force exerted by the pressure in the first chamber 14 on the piston is sufficiently high, then the piston 12 is set in motion in the direction of the first wall 18.This movement continues until a balance of forces on the piston 12 depends on the force exerted by the elastic return means 26 on the piston 12, the flow rate of fluid circulating in the first fluid line 22 and the flow rate of fluid circulating in the second fluid line 24.

[0049] When the two-way servovalve 30 is in the on state, the fluid contained in the first chamber 14 is able to flow from the first end 32 of the second fluid line 24 to the second end 34 of the second fluid line 24. If the pressure of the fluid in the first chamber 14 is sufficiently high, the fluid contained in the first chamber 14 suddenly escapes from the first chamber 14 through the second fluid line 24, the pressure in the first chamber 14 then decreasing rapidly. The force exerted by the elastic return means 26 on the piston 12 is then greater than the force exerted by the pressure of the fluid in the first chamber 14 on the piston 12.The piston 12 then moves rapidly towards the second wall of the cylinder 20, the rapid movement of the piston 12 depending at least on the force exerted by the elastic return means 26 on the piston 12, on the difference in passage section of the first and second fluid lines 22, 24 linked to the calibrated orifice 28 and to the two-way servovalve 30 and on an external force of the member controlled by the actuator 6. This movement continues until a balance of forces on the piston 12 depends at least on the force exerted by the elastic return means 26 on the piston 12, on the flow rate of fluid circulating in the first fluid line 22 and on the flow rate of fluid circulating in the second fluid line 24.

[0050] In the example of Figure 2, the movement of the piston 12 towards the first wall 18 when the two-way servovalve 30 changes from the on state to the blocking state is slower than the movement of the piston 12 towards the second wall 20 when the two-way servovalve 30 changes from the blocking state to the on state. The difference in speed between these two movements depends mainly on the ratio between a section of the first fluid line 22 comprising the calibrated orifice 28 and a section of the second fluid line 24 comprising the two-way servovalve 30 as well as on the ratio between the first pressure and the second pressure. The stiffness of the elastic return means 26 can also influence this difference in speed.The greatest speed of movement of the piston 12 towards the second wall 20 when the two-way servovalve 30 passes into the passing state is guaranteed by the passage section of the two-way servovalve 30 greater than or equal to ten times the passage section of the calibrated orifice 28. Simultaneously or alternatively to guarantee the desired speed difference between these two movements, it can be provided that the pressure drop in the first fluid line 22 is greater than or equal to ten times the pressure drop in the second fluid line 24. Optionally, the passage section of the two-way servovalve 30 is greater than twenty times the passage section of the calibrated orifice 28 to ensure a movement of the piston 12 towards the second wall 20, when the two-way servovalve 30 passes into the passing state, much faster than the movement of the piston 12 towards the first wall 18, when the two-way servovalve 30 passes into the blocking state.For example, the passage section of the two-way servovalve 30 is of the order of twenty-five times the passage section of the calibrated orifice 28.

[0051] Preferably, the cylinder 8 comprises a position sensor 44 measuring the position of the rod 10 of the cylinder 8, the actuator 6 comprising a control unit 46 configured to emit a control signal for controlling the state of the two-way servovalve 30. For example, the position sensor 44 communicates the position of the rod 10 of the cylinder 8 to the control unit 46, the control unit 46 emitting the control signal as a function of the communicated position.

[0052] Advantageously, the two-way servovalve 30 is configured so that in the absence of the control signal, for example during an electrical failure of the control unit 46 or of the two-way servovalve 30, the actuator 6 is placed in a rest position, the rest position making it possible in particular to respond to safety issues by positioning the rod 10 of the cylinder 8 in a position reducing the risks of damage to the actuator 6 and / or the turbomachine 4 and / or the aircraft 2. For example, the two-way servovalve 30 is configured to be in the on state in the absence of a command in order to quickly place the actuator 6 in the rest position.

[0053] Figure 3 schematically represents a second embodiment of the actuator 6.

[0054] The actuator 6 comprises a common conduit 48 opening into the first chamber 14. The first and second fluid conduits 22, 24 are fluidically connected to the common conduit 48, the first end 32 of the second fluid conduit 24 being connected directly to the common conduit 48. This embodiment simplifies the production of the actuator 6 and is also compatible with the embodiment of FIG. 2.

[0055] The first fluid line 22 is capable of drawing the second fluid under the second pressure from the second fluid source 42, the second fluid line 24 being capable of drawing the first fluid under the first pressure from the first fluid source 40. The first fluid line 22 comprises the calibrated orifice 28.

[0056] The two-way servovalve 30 includes the on state and the off state.

[0057] Advantageously, the two-way servovalve 30 is configured to be in a blocking state in the absence of a command in order to quickly place the actuator 6 in the rest position.

[0058] When the two-way servovalve 30 is in the on state, the first fluid taken from the first fluid source 40 is able to flow from the second end 34 of the second fluid line 24 to the first end 32 of the second fluid line 24, then from the first end 32 of the second fluid line 24 to the first chamber 14. If the pressure of the first fluid is sufficient, then the first fluid suddenly enters the first chamber 14, the pressure in the first chamber 14 then increasing rapidly. The force exerted by the pressure of the fluid in the first chamber 14 on the piston 12 is then greater than the sum of the force exerted by the elastic return means 26 on the piston 12 and the external force of the member controlled by the actuator 6.The piston 12 then moves rapidly towards the first wall 18 of the cylinder 8, the rapid movement here being against the force exerted by the elastic return means 26 on the piston 12. This movement continues until a balance of forces on the piston 12 depends at least on the force exerted by the elastic return means 26 on the piston 12, the flow rate of fluid circulating in the first fluid line 22 and the flow rate of fluid circulating in the second fluid line 24. When the two-way servovalve 30 is in the blocking state, the flow rate of fluid circulating in the second fluid line 24 is zero or very low, only the first fluid line 22 is able to allow the fluid from the first chamber 14 to escape from the cylinder 8. The pressure in the first chamber 14 decreases when the fluid from the first chamber 14 escapes from the first chamber 14 through the first fluid line 22.If the force exerted by the elastic return means 26 on the piston 12 is sufficiently high compared to the force exerted by the pressure of the fluid in the first chamber 14 on the piston 12, then the piston 12 is set in motion towards the second wall 20. This movement continues until a balance of forces on the piston 12 depends at least on the force exerted by the elastic return means 26 on the piston 12, the flow rate of fluid circulating in the first fluid conduit 22 and the flow rate of fluid circulating in the second fluid conduit 24.

[0059] In the example of Figure 3, the movement of the piston 12 toward the first wall 18 when the two-way servovalve 30 enters the on state is faster than the movement of the piston 12 toward the second wall 20 when the two-way servovalve 30 enters the off state. The greatest speed of the movement of the piston 12 toward the first wall 18 when the two-way servovalve 30 enters the on state is guaranteed by the passage section of the two-way servovalve 30 being greater than or equal to ten times the passage section of the calibrated orifice 28. Simultaneously or alternatively to guarantee the desired speed difference between these two movements, it can be provided that the pressure drop in the first fluid line 22 is greater than or equal to ten times the pressure drop in the second fluid line 24.The pressure drop in the common pipe 48 will preferably be comparable to or less than that in the second fluid pipe 24. Optionally, the passage section of the two-way servovalve 30 is greater than twenty times the passage section of the calibrated orifice 28 to ensure a movement of the piston 12 towards the first wall 18 when the two-way servovalve 30 passes into the passing state that is much faster than the movement of the piston 12 towards the second wall 20 when the two-way servovalve 30 passes into the blocking state.

[0060] Advantageously, the two-way servovalve 30 comprises a proportional control 50 capable of positioning the piston 12 in an intermediate position of the stroke of the piston 12. For example, the control unit 46 of the actuator 6 controls the proportional control 50 of the two-way servovalve 30 in an intermediate flow state so as to control the flow of air passing through the two-way servovalve 30 and therefore the second fluid line 24.

[0061] The control unit 46 is configured to control the position of the piston 12 of the cylinder 8. The control unit 46 comprises a control algorithm for controlling the position of the piston 12 in particular as a function of the position data of the position sensor 44. The control unit 46 makes it possible to quickly position the piston 12 in an intermediate position of the stroke of the piston 12.

[0062] The two-way servovalve 30 cooperates with the first and second fluid lines 22, 24 and with the elastic return means 26 to place the piston 12 in the intermediate position of the stroke of the piston 12 when the two-way servovalve 30 is in the intermediate flow state.

[0063] The intermediate position corresponds to a balance of the forces exerted on the piston 12 depending on a stiffness of the elastic return means 26, a flow rate of fluid circulating in the first fluid conduit 22 and a flow rate of fluid circulating in the second fluid conduit 24 when the two-way servovalve 30 is in the intermediate flow state.

[0064] Figure 4 schematically represents an actuation method implemented by the actuator 6.

[0065] During a first state change step 52 of the two-way servovalve 30, the operating state of the two-way servovalve 30 is modified so that the two-way servovalve 30 is in a first state. The first state comprises, for example, a passing state or a blocking state or an intermediate flow state of the two-way servovalve 30.

[0066] Then, during a first displacement step 54 of the piston 12, the piston 12 and the rod 10 of the jack 8 are moved in a first direction at a first speed, for example to bring the piston 12 closer to the first wall 18 or the second wall 20. The displacement of the piston 12 during step 54 is due to a first difference in forces acting on the piston 12 depending at least on the pressure in the first chamber 14 and the force exerted by the elastic return means 26 on the piston 12. An external force is also to be taken into account, for example an external force of the member controlled by the actuator 6. Preferably, the displacement of the piston 12 during step 54 ends when a balance of the forces acting on the piston 12 is reached.

[0067] Subsequently, during a second state change step 56 of the two-way servovalve 30, the operating state of the two-way servovalve 30 is modified so that the two-way servovalve 30 is in a second state.

[0068] The second state comprises, for example, a passing state or a blocking state or an intermediate flow state of the two-way servovalve 30.

[0069] Finally, during a second displacement step 58 of the piston 12, the piston 12 and the rod 10 of the jack 8 are moved in a second direction opposite to the first direction at a second speed, for example to bring the piston 12 closer to the second wall 20 or to the first wall 18. The displacement of the piston 12 during step 58 is due to a second difference in forces acting on the piston 12 depending at least on the pressure in the first chamber 14 and the force exerted by the elastic return means 26 on the piston 12, without taking into account the external force. Preferably, the displacement of the piston 12 during step 58 ends when a balance of the forces acting on the piston 12 is reached.

[0070] Step 52 comprises, for example, in the case of the exemplary embodiment of FIG. 2, the transition from the on state to the off state of the two-way servovalve 30 when the piston 12 is in an established on state position corresponding to the end of a first transient regime of the movement of the piston 12. Step 54 then comprises the movement of the piston 12 from the established on state position towards the first wall of the cylinder 18, the movement of the piston 12 ending when the piston 12 is in an established off state position corresponding to the end of a second transient regime of the movement of the piston 12.

[0071] Step 56 comprises, for example, in the case of the exemplary embodiment of FIG. 2, the transition from the blocking state to the passing state of the two-way servovalve 30 when the piston 12 is in the established blocking state position. Step 58 then comprises the movement of the piston 12 from the established blocking state position towards the second wall of the cylinder 20, the movement of the piston 12 ending when the piston 12 is in the established passing state position. In this example, the movement of the piston 12 during step 54 is slower than the movement of the piston during step 58.

[0072] Of course, steps 54 and 58 may include moving the piston 12 from the intermediate position of the stroke of the piston 12 to another position, or moving the piston 12 from the other position to the intermediate position of the stroke of the piston 12 or any other movement of the piston 12.

[0073] The actuation method comprises in order steps 52, 54, 56 and 58. Alternatively, such an actuation method may comprise only steps 52 and 54 or 56 and 58. Alternatively, the method may also comprise in order steps 56, 58, 52 and 54.

Claims

CLAIMS 1. Turbomachine (4) comprising an actuator (6) comprising a cylinder (8) comprising a rod (10) provided with a piston (12) delimiting at least partially within the cylinder (8) a first and a second chamber (14, 16), the actuator (6) comprising a first and a second fluid line (22, 24) fluidly connected to the first chamber (14), an elastic return means (26) in a predetermined position arranged in one of the first and second chambers (14, 16) and configured to exert a force on the piston (12), the first fluid line (22) comprising a calibrated orifice (28), the actuator (6) comprising a two-way servovalve (30) fluidly connected to the second fluid line (24),a passage section of the two-way servovalve (30) being greater than or equal to ten times a passage section of the calibrated orifice (28) or the pressure drop in the first fluid line (22) being greater than or equal to ten times the pressure drop in the second fluid line (24), the turbomachine (4) comprising a first fluid source (40) and a second fluid source (42), one of the first and second fluid lines (22, 24) being configured to take a first fluid from the first fluid source (40), the other fluid line (24, 22) being configured to take a second fluid from the second fluid source (42), the pressure of the first fluid being greater than the pressure of the second fluid, characterized in that the first fluid source (40) comprises a compressor of the turbomachine (4), the second fluid comprising air under atmospheric pressure.

2. Turbomachine (4) according to claim 1, in which the actuator (6) comprises a common pipe (48) opening into the first chamber (14), the first and second fluid pipes (22, 24) being fluidically connected to the common pipe (48).

3. Turbomachine (4) according to one of claims 1 and 2, in which the two-way servovalve (30) comprises an electromagnetic control (36).

4. Turbomachine (4) according to any one of claims 1 to 3, wherein the two-way servovalve (30) is configured to have at least one passing state such that a fluid can flow in the second fluid line (24) through the two-way servovalve (30) and a blocking state such that a fluid cannot flow in the second fluid line (24) through the two-way servovalve (30).

5. Turbomachine (4) according to any one of claims 1 to 4, wherein the two-way servovalve (30) comprises a proportional control (50) configured to position the piston (12) in an intermediate position of a stroke of the piston (12).

6. Turbomachine (4) according to any one of claims 1 to 5, in which the piston (12) is associated with a sealed rolling membrane (38) to sealably separate the first and second chambers (14, 16).

7. Turbomachine (4) according to any one of claims 1 to 6, in which the passage section of the two-way servovalve (30) is greater than twenty times the passage section of the calibrated orifice (28).

8. Aircraft (2) comprising a turbomachine (4) according to any one of the preceding claims.

9. Actuation method implemented by an actuator (6) included in a turbomachine (4) according to any one of claims 1 to 7, or by an actuator (6) included in a turbomachine (4) included in an aircraft (2) according to claim 8, comprising the following steps: changing the state of the two-way servovalve (30) so that the two-way servovalve (30) is in a first state; moving the piston (12) and the rod (10) in a first direction at a first speed, said movement being due to a first difference in forces acting on the piston (12) depending at least on the pressure in the first chamber (14) and the force exerted by the elastic return means (26) on the piston (12); and / or changing the state of the two-way servovalve (30) so that the two-way servovalve (30) is in a second state; and moving the piston (12) and the rod (10) in a second direction opposite to the first direction at a second speed different from the first speed, said movement being due to a second difference in forces acting on the piston (12) depending at least on the pressure in the first chamber (14) and the force exerted by the elastic return means (26) on the piston (12).

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