Actuator cylinder for turbomachine blade

Abstract

This presentation concerns a turbomachinery actuator (200) comprising a cylinder (202) with longitudinal axis (Y), a piston (206) arranged within the cylinder (202) and dividing the cylinder (202) into two chambers (208, 210), and a rod (204) connected to the piston (206). The piston (206) is configured to move along the longitudinal axis (Y) under the effect of a fluid present in one of the chambers (208, 210), and the rod (204) is parallel to the longitudinal axis (Y) and is arranged at a non-zero distance from the longitudinal axis (Y). Figure to be published with the abstract: Figure 3

Description

Description Title of the invention: Actuating cylinder for turbine blade bomachine Technical field of the invention

[0001] = The present description relates to an actuating cylinder, in particular a cylinder actuation for a turbomachine blade. Prior art

[0002] = An assembly for an aircraft turbomachine is shown in [Fig.1], on which the upstream (AM) and downstream (AV) of the structure along a driving axis, i.e. the longitudinal axis The central part of the turbomachine 10, forming the gas turbine engine 12, is located respectively to the left and right of [Fig. 1].

[0003] The central part of the turbomachine 10, forming the gas turbine engine 12, is mounted inside a 14-unit engine nacelle assembly, as is typical of an aircraft designed for subsonic operation, such as a turboprop or a turbofan engine. The nacelle assembly 14 typically includes a engine nacelle 16 and a blower nacelle 18 surrounding a blower 20 located axially upstream of motor 12.

[0004] — The engine 12 comprises, axially in its downstream part, at least one turbine which can to be a low-pressure turbine and, further downstream, an exhaust casing 22 including an internal annular ferrule 22a and an external annular ferrule 22b limiting between them a downstream part of the primary annular vein 24 in which the combustion gases from the combustion chamber of engine 12 circulate according to the direction F.

[0005] The internal annular ferrule 22a is connected, at its downstream end, to the ejection cone 1, which may include an upstream part, substantially cylindrical in shape, and a downstream part 1b of conical shape.

[0006] — The motor 12 includes, axially in its upstream part, at least one compressor. In a twin-spool turbomachine with a twin-compressor configuration Separated axially, the upstream compressor is a low-pressure compressor and the The downstream compressor is a high-pressure compressor. comprises a succession of compression stages, each containing a row annular array of movable blades mounted on a rotor shaft and an annular row variable-pitch stator blades mounted at their radially external ends on an external casing of the high-pressure compressor of the turbomachine 10.

[0007] — Adjusting the angular timing of the stator blades in the high-pressure compressor The pressure of turbomachine 10 is intended to optimize the efficiency of this tur- bomachine and to reduce its fuel consumption in the different phases of flight. Variable-pitch stator blades each include at their outer radial end a radial pivot that is centered and guided for rotation within an opening in the outer casing. Each blade pivot is connected by a connecting rod to a control ring that extends around the outer casing of the compressor and is rotatable around the longitudinal axis of the compressor by actuation means to transmit rotational motion to the blades around the axes of their pivots. To move the control ring, it is generally connected by a lever to a control shaft actuated by at least one actuator. However, the mounting of the control ring and its connection to at least one cylinder remain complicated to implement due to the lack of space around the compressor, particularly in the inter-vein compartment located between the primary annular vein 24 and a secondary annular vein arranged between the blower nacelle 18 and the engine nacelle 16. There is a need to simplify the mounting of the cylinders in the turbomachine. Summary of the invention To this end, the present exposition proposes a turbomachine cylinder comprising a longitudinal axis cylinder, a piston arranged in the cylinder and separating the cylinder into two chambers, and a rod connected to the piston, the piston being configured to move along the longitudinal axis under the effect of a fluid present in one of the chambers, and in which the rod extends along an axis parallel to the longitudinal axis and arranged at a non-zero distance from the longitudinal axis. Unlike the known technique, this cylinder features an actuating rod that is not coaxial with the cylinder forming the cylinder body. This allows the cylinder to be mounted in a turbomachine compartment near a wall, such as a cowling delimiting an aerodynamic duct of the turbomachine, particularly the secondary duct, while the cylinder body is positioned at a sufficient distance from the wall to provide acceptable clearance. This prevents, in particular, collisions between the cylinder and the wall during operation due to their relative displacements caused by vibrations and thermal variations. Despite the necessary clearance between the cylinder and the wall, the fact that the actuating rod is offset from the cylinder body allows the actuating rod to interface with a kinematic chain whose position within the compartment is fixed and which can be relatively close to the wall. In comparison, a conventional cylinder with a non-offset actuating rod interfaced with the same kinematic chain would require the cylinder body to be moved closer to the wall, since the position of the rod relative to the kinematic chain must remain unchanged. This would involve either reducing the clearance between the cylinder and the wall, but in this case the clearance would be unacceptable, or moving the wall away from the cylinder body to maintain an acceptable clearance, but at the expense of the cross-section of the aerodynamic duct concerned, which would then be reduced. The cylinder can be arranged in a compartment of the turbomachine in the vicinity of a wall, for example a hood delimiting an aerodynamic duct of the turbomachine, in particular a secondary duct arranged between a fan and a turbomachine engine. The cylinder can be a right cylinder with a convex base, more specifically a right circular cylinder. The cylinder may include a wall which has an inner surface having a cylindrical portion along which the piston can move. The distance between the stem and the longitudinal axis can be between 50% and 90% of the radius of the cylindrical portion. The cylinder may include a wall which has an inner surface having a cylindrical portion along which the piston moves, and the distance between the axis of the rod and the longitudinal axis may be between 50% and 90% of the radius of said cylindrical portion. The fluid can be a hydraulic or pneumatic fluid. The cylinder may include means for guiding the piston in translation along its longitudinal axis. For example, the guiding means may include a guide bearing surrounding the rod and arranged in an opening provided in the cylinder to receive the rod. One or more seals mounted around the moving piston and in contact with an inner wall of the cylinder may also constitute means for guiding the piston. The present presentation still concerns a turbomachine comprising at least one cylinder as mentioned above. In particular, the turbomachine includes at least one compressor, for example a high-pressure compressor. The compressor comprises a series of compression stages, each having an annular row of moving blades mounted on a rotor shaft and an annular row of stator blades, in particular stator blades with variable pitch. At least one cylinder is arranged to control the orientation of the variable-pitch stator blades. The compressor may include a variable-pitch stator vane control ring associated with a connecting rod, one end of which is connected to the control ring and the other to an external radial rod of the radially external end of at least one or all of the stator vanes. The rotation of the ring under the effect of the cylinder can move some or all of the connecting rods and therefore the blades around their respective axes. At least one cylinder can be connected to the variable-pitch stator vane control ring. In particular, the rod of at least one cylinder can be connected to the external radial rod. The turbomachine may include two cylinders diametrically opposed to each other with respect to an axis of rotation of the rotating parts, namely the axis of rotation of the annular rows of stator blades. Brief description of the figures [Fig.1] The [Fig.1], already described, represents a schematic profile section of an aircraft turbomachine. [Fig.2] [Fig.2] is a partial schematic half-view in axial section of a high-pressure compressor of a turbojet engine equipped with a variable-pitch blade control system, [Fig. 3] [Fig. 3] is a schematic representation of an example of an embodiment of a cylinder that can be used to control variable-pitch blades. Detailed description of the invention With reference to [Fig. 2], which represents a schematic half-view of the upstream part of a compressor 100, for example a high-pressure compressor, of a turbomachine, in cross-section along a plane passing through the axis of rotation X of the turbomachine, which may be the turbomachine of [Fig. 1]. The high-pressure compressor 100 comprises alternating annular rows of movable blades 112, or rotor wheels, and annular rows of fixed blades 114, also called the stator. The term "stator" in the expression "stator blade" refers to a blade that does not move around the longitudinal axis X of the turbomachine. The stator blades 116 are of the variable-pitch type in order to adjust their position, in particular their angle of rotation, around their axes A to optimize the gas flow in the turbomachine engine. Each variable-pitch stator blade 116 comprises a blade 118 connected to a cylindrical pivot 120, 122 at each of its radially internal and external ends. These internal pivots 120 and external pivots 122 define the axis A of rotation of the variable-pitch stator blade 116. The radially external pivot 122 is engaged in a cylindrical chimney 124 of an external annular housing 126 of the turbomachine. For each annular row 114 of blades, the external pivots 122 are connected by a connecting rod 128 to a control ring 130 mounted around the housing 126. The control ring 130 can rotate about an axis B. The radially internal pivot 120 of each variable-pitch stator blade 116 is engaged in an opening of an annular ferrule. Internal 132. As can be seen in [Fig. 2], each row of variable-pitch stator blades 114 is longitudinally interposed between an upstream rotor wheel 112 and a downstream rotor wheel 112. The rotor wheels 112 are internally connected by connecting means extending radially within the annular rows 114 of stator blades. These connecting means include, in particular, a ring of annular scrapers cooperating with an abradable material integral with the annular shell 132. To facilitate the rotation of the external pivots 122 of the blades 116 in the external housing 126, the external pivots 122 are mounted in bushings 138 housed in the chimneys 124 of the external housing 126. In addition, clearances are provided between the external pivots 122 and the bushings 138 to ensure proper mounting of the external pivots 122 in the bushings 138 and the correct rotation of the external pivots 122. These clearances are dimensioned to prevent the radially inner end of the blade row 114 from moving longitudinally. Each control ring 130 is mounted around the housing 126 and is connected by a lever to a control shaft actuated by a cylinder. Alternatively, a single cylinder is used to actuate all the control rings 130 simultaneously. The angular pitch adjustment of the stator blades 26 of a stage is ensured by means of the connecting rods 128 which are driven in rotation by the control ring 130 mounted pivotally relative to the housing 126 around an axis B. The total travel of the control ring is, for example, between 5 and 20°. The control ring 130, for example, is formed of two parts assembled to each other by means of fasteners fixed to the ends of said parts. When the control ring 130 rotates around its axis B, it causes the connecting rods 128 and the stator blades 114 to pivot around the axis of the pivots 120,122 of the stator blades 114. All, or part of, the stator blades 114 are then in the same angular position, for a given angular position of the control ring 130. For example, the connecting rods 128 can all have the same length. Generally, the end of each connecting rod 128 fixed to the stator blade pivot 122 114 is held radially on a rim of the bushing 138 by a nut screwed onto the end of the pivot 120. The other end of the connecting rod 128 includes an orifice in which a radial cylindrical pin mounted in a cylindrical hole of the control ring 130 is guided in rotation. As can be seen in [Fig.2], many control and motion transmission elements are arranged around the annular rows of stator blades 114, which complicates the assembly of the compressor 100, in particular the assembly of the cylinders controlling the connecting rods 128. A cylinder 200 is shown in [Fig.3] suitable for mounting in the compressor 100 to order the 128 connecting rods while facilitating the assembly of the 100 compressor. The cylinder 200 comprises a cylinder 202 with axis Ÿ having an internal volume and a rod 204 connected to a movable piston 206 in the cylinder 202. The rod 204 extends along an axis Z parallel to the axis Y and arranged at a non-zero distance from the latter. Thus, unlike the known design, cylinder 200 has a rod that is not coaxial with the cylinder. This reduces the overall size of the cylinder, particularly the rod on one side of cylinder 200. Cylinder 200 can be mounted more easily in compressor 100. The cylinder 200 includes a wall which has an inner surface 216 having a cylindrical portion along which the piston moves. The distance between the rod and the axis Ÿ of the cylinder 202 is preferably between 50% and 90% of the radius of the cylindrical portion of the inner surface 216. The movable piston 206 separates the internal volume of the cylinder 202 into two chambers 208, 210 delimited by said movable piston 206. To ensure the seal between the two chambers 208, 210, a sealing gasket 212 is mounted around the movable piston 206 and is in contact with an internal wall of the cylinder 202. Each chamber 208, 210 can be equipped with chamber purging means or fluid admission means. The fluid admitted into chamber 208 or 210 allows the movable piston to move in one direction or the other along the Z-axis and can be a hydraulic or pneumatic fluid. The rod 204 can be connected to the drive shaft driving the rotation of the drive ring 130 of at least one annular row of stator blades 114. To ensure that the rod 204 remains aligned along the Z-axis, guide means can be installed in the cylinder 200. These guide means may include a guide bearing arranged in an orifice 214 of the cylinder 202 that receives the rod 204. More specifically, as shown in the figure, the guide bearing may consist of a cylindrical bore forming the orifice 214 and located in an axially projecting portion 218 of the cylinder body 200. This projecting portion 218 is situated on a base of the cylinder 202 and extends outward from the base in the direction of the Z-axis. This cylindrical bore may be provided with at least one seal against the rod 204 to prevent the fluid in the chamber 208 from escaping through the necessary operating clearance provided between the rod 204 and the cylindrical bore. Cylinder 202 can be a right cylinder with a convex base, more particularly a right circular cylinder. Advantageously, the compressor 100 can comprise two cylinders 200 arranged around one or more annular rows of blades. The two cylinders can be diametrically opposed to each other with respect to the axis of rotation X of the compressor. presser 100. The applications of the present invention in a turbomachine are not limited to valve actuation cylinders. All cylinders present in a turbomachine can potentially be concerned, including cylinders of a variable area nozzle system, cylinders of an LPTACC (“Low Pressure Turbine Active Clearance Control”) or HPTACC (“High Pressure Turbine Active Clearance Control”) system, or cylinders of a thrust reversal system.

Claims

Demands

1. Cylinder (200) for turbomachine (100) comprising a cylinder (202) with longitudinal axis (ŸY), a piston (206) arranged in the cylinder (202) and separating the cylinder (202) into two chambers (208, 210), and a rod (204) connected to the piston (206), the piston (206) being configured to move along the longitudinal axis (Ÿ) under the effect of a fluid present in one chambers (208, 210), and in which the rod (204) extends along an axis {Z) parallel to the longitudinal axis (Y) and arranged at a non-zero distance of the latter.

2. Cylinder (200) according to claim 1, wherein the cylinder (202) includes a wall which has an interior surface (216) having a cylindrical portion along which the piston (206) moves, and the distance between the axis (Z) of the rod (204) and the longitudinal axis (ŸY) is comprising between 50% and 90% of the radius of said cylindrical portion.

3. Cylinder (200) according to claim 1 or 2, wherein the fluid is a hydraulic fluid.

4. Cylinder (200) according to claim 1 or 2, wherein the fluid is a pneumatic fluid.

5. Cylinder (200) according to any one of claims 1 to 4, comprising means of guiding the piston (206) in translation along the longitudinal axis gitudinal (Y).

6. Turbomachine comprising at least one cylinder (200) according to one of the re- previous demands.

7. Turbomachine according to the preceding claim, wherein the at least a cylinder (200) is connected to a stator blade control ring (114) with variable calibration.

8. Turbomachine according to claim 6 or 7, comprising two cylinders (200) diametrically opposed to each other with respect to an axis rotation (X) of the rotating parts.

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