TURBOMACHINE MODULE COMPRISING VARIABLE PITCH BLADES AND A VARIABLE PITCH SYSTEM WITH LINKING ELEMENTS

Abstract

The invention relates to a longitudinal-axis turbomachine module, particularly for aircraft, comprising a plurality of variable-pitch blades (2) about the longitudinal axis and a blade pitch-changing system (3) for the blades (2). The pitch-changing system comprises at least one control means connected to a foot (4) of at least one of the blades so as to control its rotation about its pitch axis (A), and connecting elements (32) arranged about the longitudinal axis. According to the invention, each connecting element is arranged between adjacent blades about the longitudinal axis, and each connecting element is connected by hinged links to both the feet (4) of the blades and to an adjacent connecting element. Each connecting element is configured to transmit the rotational motion of the blade controlled by the control means to at least one other blade. (See Fig. 5 for abbreviations.)

Description

Title of the invention: TURBOMACHINE MODULE COMPRISING VARIABLE PITCH BLADES AND A VARIABLE PITCH SYSTEM WITH CONNECTING ELEMENTS Technical field of the invention

[0001] The present invention relates to the aeronautical field, in particular aircraft propulsion. It relates to a turbomachine module comprising variable-pitch blades and more particularly to a system for changing the pitch of the variable-pitch blades. Technological background

[0002] Many turbomachines, such as turbojets or turboprops, are equipped with variable-pitch blades. The different operating modes and positions of the variable-pitch blades allow them to adapt to various turbomachine speeds.

[0003] These pitched vanes may be, for example, stator vanes which are known by the English acronym "OGV" for Outlet Guide Vane and which are arranged around the longitudinal axis of the turbomachine. These stator vanes radially cross a flow and are placed downstream of moving vanes in order to straighten the flow at the outlet of these moving vanes. For this purpose, the variable pitch vanes are connected to a pitch change system which is configured so as to vary the pitches or inclinations of these around their pitch axis during a flight.

[0004] The pitch change system generally comprises a jack which is connected to the variable-pitch blades by means of connecting means. These connecting means can transmit a torque to all of the blades so that they have the same pitch during a given operating mode. These connecting means comprise, for example, a control ring movable in translation or in rotation, connecting rods each connected to the control ring and to a single blade, and levers. An example of this pitch change system is described in document FR-A1-3098788.

[0005] These connecting means, however, have drawbacks. These connecting means require a sufficient annular space to accommodate the control ring and the connecting rods, and which is clean to guarantee the reliability of the timing. With the number of parts in this pitch change system to achieve the kinematics, an accumulation of inaccuracies and defects may appear. Furthermore, the pitch change system is installed in an area where the pylon is located, allowing the turbomachine to be suspended under the wing of the aircraft, and which may complicate the arrangement of the pitch change system.

[0006] There is a need to resolve all or part of the aforementioned drawbacks. Summary of the invention

[0007] The objective of the present invention is to provide a solution for safely and efficiently integrating setting means providing uniform and simultaneous setting on all the variable-pitch blades in a simple, economical and robust manner.

[0008] We achieve this objective in accordance with the invention by means of a longitudinal axis turbomachine module, in particular an aircraft module, the module comprising a plurality of blades with variable pitch around the longitudinal axis and a system for changing the pitch of the variable pitch blades, the pitch change system comprising at least one control means connected to a root of at least one of the variable pitch blades so as to control its rotation around its pitch axis and connecting elements which are arranged around the longitudinal axis, each connecting element being arranged between adjacent variable pitch blades around the longitudinal axis and each connecting element being connected by articulated connections both to the roots of the variable pitch blades and to an adjacent connecting element,each connecting element being configured so as to transmit the rotational movement of the variable-pitch blade controlled by the control means to at least one other variable-pitch blade.

[0009] Thus, this solution makes it possible to achieve the aforementioned objective. In particular, this configuration makes it possible to simplify the timing system by reducing the number of parts that compose it and to make the timing of the blades more reliable. The reduction in the number of parts facilitates the implementation and maintenance of the timing system. The angular timing obtained thanks to this configuration is identical and simultaneous from one variable-pitch blade to another; the kinematics are perfect, that is to say that it retransmits to the theory exactly the same angle from one variable-pitch blade to another without any dispersion. Added to this is the fact that the arrangement of the connecting elements makes it possible to free up certain spaces which make it possible to reduce the mass of the system, or to provide in a simple manner the passage of services.

[0010] The turbomachine module also comprises one or more of the following features and / or steps, taken alone or in combination:

[0011] - the pitch change system comprises connection members which are arranged around the longitudinal axis and which are each connected to a foot, the connecting elements being mounted so as to be separated by at least one connecting member and each being articulated to a connecting member.

[0012] - the articulated connection between each connecting element and a connection member is a ball joint.

[0013] - each foot is connected to a connection member by a sliding link.

[0014] - the connecting elements comprise connecting rods.

[0015] - the foot of each variable-pitch blade is mounted to move around an axis of wedging in a support member which is connected to a stator of the turbomachine, each connection member being connected in an articulated manner to the support member.

[0016] - each connection member comprises at least one roller mounted to slide in a guide path carried by the support member.

[0017] - the pitch change system comprises a control arm which is of a part, integral with the foot of a variable-pitch blade controlled by the control means and which is on the other hand connected to the movable body of the control means.

[0018] - the pitch change system comprises several control means distributed around the longitudinal axis and each control means is connected to the root of a single variable-pitch blade via the control arm and each connecting element is connected to a blade root and to an adjacent connecting element around the longitudinal axis.

[0019] - a foot controlled by a control means comprises a control arm and a leg connected to at least one of the connecting elements and a follower foot controlled via at least one of the connecting elements comprises a single leg.

[0020] - a control means is intended to control at least two pitched blades variable.

[0021] The invention relates to a turbomachine, in particular for an aircraft, comprising at least one turbomachine module having any one of the aforementioned characteristics. Brief description of the figures

[0022] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly on reading the detailed explanatory description which follows, of embodiments of the invention given as purely illustrative and non-limiting examples, with reference to the appended schematic drawings in which:

[0023] - [Fig.l] is a perspective view of an annular row of pitched vanes variable according to the invention;

[0024] - [Fig.2] is an upstream view of a set of blade root support members connected to a connecting mechanism of a pitch change system according to the invention;

[0025] - [Fig.3] is a detailed and partial view of an example of a blade root which is connected to a control means and to connecting elements according to the invention;

[0026] - [Fig.4] is a detailed and partial view of a variable pitch blade root cooperating with a pitch change system according to the invention;

[0027] - [Fig.5] is a perspective and partial view of an articulated connection between elements of a pitch change system according to the invention;

[0028] - [Fig.6] is a perspective view of a connecting member connected to a connecting member blade root support according to the invention; and

[0029] - [Fig.7] is a perspective and side view of the connection member according to the [Fig.6]. Detailed description of the invention

[0030] [Fig.l] represents a turbomachine module 1 with longitudinal axis X. The turbomachine is intended to be mounted on an aircraft. The turbomachine may be a turbomotor, a turbojet, a turbofan, or may comprise moving fan blades or moving blades of at least one propeller which are shrouded or unshrouded.

[0031] The turbomachine module 1 comprises a plurality of variable-pitch blades 2 which are distributed around the longitudinal axis X. For this purpose, the turbomachine 1 comprises a pitch-changing system 3 which is configured to change the pitch of the blades 2 depending on the operating mode of the turbomachine. These variable-pitch blades 2 may be moving blades or stator blades.

[0032] In the present invention, the term "stator blade" or "fixed blade" means a blade that is not driven in rotation about the longitudinal axis X of the turbomachine. In other words, the stator blade is distinct from and opposite a moving or rotor blade of the turbomachine. The stator blades and the moving blades are generally arranged in the form of an annular row and the annular rows of stator blades are arranged upstream and / or downstream of the annular rows of moving blades along the longitudinal axis X.

[0033] In the present invention, and generally, the terms "upstream" and "downstream" are defined with respect to the circulation of gases or air flows in the turbomachine and here along the longitudinal axis X. The terms "axial" and "axially" are defined with respect to the longitudinal axis X. The terms "external", "external", "internal", "internal" and "radial" are defined with respect to a radial axis Z which extends from the longitudinal axis X and with respect to the distance from the longitudinal axis X. The radial axis is perpendicular to the longitudinal axis X.

[0034] In an exemplary embodiment, the moving blades are fan blades or propeller blades and the stator blades are outlet guide vanes, known by the English acronym “OGV” for Outlet Guide Vane which are placed downstream of the moving blades.

[0035] In another exemplary embodiment, the turbomachine 1 comprises a compressor assembly (not shown) and a turbine assembly (not shown) which are placed on either side of a combustion chamber (not shown) along the longitudinal axis X. The compressor assembly and the turbine assembly each comprise several rows of moving blades and stator blades which are alternated along the longitudinal axis X. The stator blades are known under the term "straightener" or by the English acronym "VSV" for Variable Stator Vane. These make it possible to straighten the flow which passes through them. The stator blades of the compressor assembly or of the turbine may be variable-pitch.

[0036] Preferably, the variable-pitch blade is a stator blade.

[0037] With reference to [Fig. 1], each variable-pitch blade 2 comprises a root 4 and a blade 5 which extends radially from the root 4. Each blade 5 comprises a leading edge 5a and a trailing edge 5b which are connected by an extrados surface 5e and a intrados surface 5i.

[0038] The root 4 of each blade 2 is typically in the form of a pivot which is pivotally mounted along a setting axis A in an internal housing 6. The setting axis A extends substantially parallel to the radial axis Z. The setting axis A may have an inclination of between 5° and 10° relative to the radial axis Z. The pivoting of the variable-pitch blades 2 makes it possible to modify their setting angle and for one of the intrados surfaces 5i and extrados surface 5e to be more or less exposed to the air flow depending on the speed of the turbomachine.

[0039] [Fig. 2] illustrates several roots 4 of variable-pitch blades 2 which are each pivotally mounted in a support member 7 and which are adjacent in the circumferential direction around the longitudinal axis X. For this, each support member 7 comprises a substantially cylindrical wall 8 having an axis of revolution which is centered on a setting axis A. Each cylindrical wall 8 delimits the internal housing 6 respectively receiving a blade root 4. Each cylindrical wall 8 is open at each of its opposite ends 8a, 8b along the setting axis A and the openings open into the internal housing 6 (see [Fig. 6]).

[0040] At least one bearing (not shown) is mounted in each internal housing 6 to ensure the centering and guiding of a foot 4. Preferably, two bearings are mounted in each internal housing 6 and are superimposed along the wedging axis A. In particular, each bearing comprises an internal ring and an external ring between which rolling members are arranged. The latter may be balls or rollers. Each internal ring may be secured to an external surface of the foot 4 and each external ring may be secured to the internal surface of the cylindrical wall 8 of the support member 7.

[0041] With reference to [Fig.3], the support members 7 are distinct from one another. This configuration makes it possible to reduce the space between the blades 2, which makes it possible to install other members there. Advantageously, each support member 7 is connected to a stator 9 of the turbomachine. That is to say, these are fixed in rotation and in translation. The turbomachine 1 comprises an annular casing 10 centered on the longitudinal axis X. The annular casing 10 comprises an annular flange 11 which extends radially outwards. Each support member 7 comprises at least one protrusion 12 which is fixed to the annular flange 11 using fixing members (not shown). In the present example, four protrusions 12 extend transversely from the cylindrical wall 8 of each support member 7. The annular flange 11 may also comprise, as is the case in the example of [Fig. 3], corresponding protrusions 13 of the protrusions 12. These corresponding protrusions 13 extend axially from the flange 11.The fixing members may be screws, nuts, bolts, etc. The fixing members cooperate with the protrusions 12 and corresponding protrusions 13 for fixing the support members 7.

[0042] Advantageously, but not limitingly, each foot 4 comprises a barrel 15 which extends along the setting axis A and to which the or each internal ring of a bearing is secured. Advantageously, but not limitingly, each foot 4 comprises a plate 14 which is intended to be fixed to a platform (not shown) which is located at one end of the root of the blade 5. The fixing between the platform and the plate 14 can be achieved by bolt-type fixing members or other suitable means. Each plate 14 and each platform comprise for this purpose orifices cooperating with the fixing members. Each plate 14 extends radially from one end of the barrel 15 of the foot 4. As a variant, the root 4 and the blade 5 are formed from a single piece (made in one piece) and the plate 14 is formed between the root 4 and the blade 5.

[0043] In the example shown, each plate 14 has a circular shape centered on the wedging axis A. Of course, each plate 14 could have a rectangular or other shape which does not hinder its movement and which is not bulky.

[0044] With reference to Figures 2 and 3, the pitch change system 3 comprises at least one control means 20 which is connected to a root 4 of at least one of the variable-pitch blades 2 so as to control its rotation about its pitch axis A. Advantageously, but not limitingly, the control means 20 comprises a fixed body 21 and a body 22 which is movable relative to the fixed body 21. The control means 20 is connected to a fluid supply source (not shown) for supplying pressurized oil to chambers (not shown) which are formed between the fixed body 21 and the movable body 22.

[0045] The mobile body 22 moves here in translation along the longitudinal axis X. Avanta Conveniently, the movable body 22 is connected to a foot 4 via a control arm 23. In other words, the control arm 23 is integral with the foot 4 of the blade which is controlled (directly) by the control means 20.

[0046] The control arm 23 may extend from a peripheral edge 24 of the plate 14 or from an internal surface 25 (see FIGS. 2 and 6) of the plate 14. The control arm 23 is for example formed in a single piece with the foot 4 so as to facilitate manufacturing and assembly. The free end 26 of the control arm 23 secured to the foot 4 is connected for example to a rod 27 of the movable body 22. The rod 27 extends along the longitudinal axis X. Here, the rod 27 is arranged circumferentially between two adjacent variable-pitch vanes 2.

[0047] Advantageously, but not limitingly, the free end 26 of the control arm 23 comprises a fixing clevis 28 formed of two mounting lugs 28a, 28b which are parallel to each other. Alternatively, the free end 26 can comprise a single mounting lug. Each mounting lug 28a, 28b is pierced with an orifice passing through it on either side. The axis of the orifices is here parallel to the radial axis. Here the free end 27a of the rod 27 is also pierced by an orifice with a radial axis. The orifices of the lugs 28a, 28b and of the free end 26 are crossed for example by a fixing pin 29. In this way, when the movable body 22 moves in translation, a rotational movement is transmitted to the plate 14 via the control arm 23 which is integral with the controlled foot. The foot 4 of the blade which carries this plate 14 pivots in the corresponding support member 7.

[0048] As illustrated in [Fig. 3], the fixed body 21 is connected to a stator of the turbomachine so as to be immobile in rotation and in translation. In the present example, the stator is the annular casing 10. The latter may comprise holding means (such as panels) to hold the control means 20 in position and make the assembly more reliable. Advantageously, but not limitingly, the flange 11 comprises an opening 30 which passes through its wall on either side along the longitudinal axis X and which is crossed by the rod 27. A portion of the fixed body 21 may be held at the opening 30 of the flange 11.

[0049] According to an advantageous characteristic, the pitch change system 3 comprises several control means 20 which are distributed around the longitudinal axis X. Each control means 20 is advantageously arranged along the longitudinal axis X and acts directly on the roots 4 of the variable-pitch blades 2. However, the number of control means 20 is less than that of the variable-pitch blades 2.

[0050] In the present example illustrated in [Fig.2], there are two control means 21. A third control means may be envisaged. Each control means 20 is connected to a single variable-pitch blade root 4 via a control arm. control 23. Each root 4 of a variable-pitch blade 2 which is connected to a control means 20 is considered to be a controlled blade root or a master root. In other words, not all the blades 2 (or roots 4) are connected to the control means 20 via control arms 23 but only some of them. The other blade roots 4 not directly connected to the control means 21 via the control arm 23 are considered to be follower blade roots or slave roots. In particular, the number of controlled blade roots 4 is equal to the number of control means 20 installed in the turbomachine module.

[0051] The pitch change system 3 comprises at least one connecting mechanism 31 which makes it possible to connect at least one control means 20 to at least one blade root 4.

[0052] With reference to Figures 1 and 4, several connecting elements 32 are arranged around the longitudinal axis X. Advantageously, the connecting elements 32 are arranged between the roots of the variable-pitch blades 2. Each connecting element 32 is connected by articulated connections both to the variable-pitch blades 2 (in particular the roots 4) and to an adjacent connecting element 32 around the longitudinal axis X. Each connecting element 32 is configured so as to transmit the rotational movement of the variable-pitch blade 2 controlled (or blade root controlled) by a control means 20 to at least one other variable-pitch blade 2.

[0053] For this purpose, the pitch change system 3 comprises connection members 33 which are arranged around the longitudinal axis X. The connection members 33 are distinct from one another. Each connection member 33 is connected to a blade root 4. Advantageously, but not limitingly, each connection member 33 is mounted in a sliding connection with a root 4. As can be seen in [Fig. 4], each plate 14 is optionally provided with a tab 34 which here extends transversely from the peripheral edge 24 of the plate 14. Optionally, each tab 34 is formed in a single piece with the root 4. In the case where the root 4 carries a control arm 23, the tab 34 is arranged at a distance from it and preferably at an angle of approximately 90°. In other words, a controlled blade root comprises a control arm 23 and a single lug 34 while a follower root is provided with only a single lug 34.

[0054] Each leg 34 comprises, towards its free end, a guide element 35 which is provided with a through hole 36 with axis B parallel to the wedging axis A. Each connection member 33 comprises a pin 37 (visible in [Fig. 3]) intended to engage in the through hole 36 to carry out a translation along the axis B. Alternatively, each leg 34 comprises the pin 37 which engages in a hole (through or non-through) of the connection member 33. The axial section of the guide element 35, in the form of an L for example, makes it possible to guide the movement of the connection member 33. This configuration makes it possible to ensure that the center of the ball joints (at the level of the connecting member 33) is always at the same radial distance from the longitudinal axis.

[0055] The connecting elements 32 and the connecting member 33 are part of the connecting mechanism 31.

[0056] As illustrated in [Fig. 4], the connecting elements 32 are articulated with the connecting members 33. More precisely, the connecting elements 32 are regularly arranged alternating with the connecting members 33 around the longitudinal axis X. Even more precisely, the connecting elements 32 are separated by a connecting member 33. In other words, each connecting element 32 is articulated with two connecting members 33. The articulated connection is preferably a ball joint. Indeed, ball joints offer better precision and reduce the train effect. We consider the train effect in the present application by the fact that a connecting rod which is not connected to a connecting rod which is closest or connected to a controlled blade root will move or start moving when the clearance between the intermediate connecting rods is filled.

[0057] The connecting elements 32 advantageously comprise connecting rods 38. Each connecting rod 38 extends between a first end 39a and a second end 39b. According to an exemplary embodiment, the connecting rods 38 are adjustable connecting rods. That is to say that the length measured between the first end and the second end can vary.

[0058] With reference to [Fig. 5], each first end 39a and second end 39b comprises a sphere 40. Each connecting member 33 comprises at least one spherical surface 41 complementary to the surface of the sphere 40 of each connecting rod 38 to produce the ball joint. In other words, each connecting member 33 comprises two spherical surfaces 41 which are opposite in the circumferential direction. The spherical surfaces 41 are formed in a body 42 of each connecting member 33. The body 42 here has a cubic shape. In this way, the rotational movement of a blade root 4 is transmitted to all the variable-pitch blades.

[0059] With reference to Figures 6 and 7, each connection member 33 is connected to a support member 7 of the plurality of variable-pitch blades 2. Advantageously, an articulation is provided between each support member 7 and each connection member 33. The articulation is achieved using at least one roller 45 or pad slidably mounted in a guide path 46. In the present exemplary embodiment, the roller 45 is carried by the connection member 33 while the guide path 46 is carried by the support member 7. Of course, the connection member 33 could carry the guide path 46 and the support member 7 carry the roller. This configuration makes it possible to completely eliminate the train effect between the different connecting rods of the connecting elements 32.

[0060] Each connecting member 33 comprises a wing 47 which extends transversely from the body 42 of a connecting member 33. The wing 47 is oriented opposite the cylindrical wall 8 of the support member 7. Advantageously, each wing 47 is arranged on a face perpendicular to the faces in which the peripheral surfaces 41 are provided for the ball joint connection. Here, a roller 45 is arranged on either side of the wing 47. Alternatively, the or each roller 45 is carried by a rod secured to the body 42. Each guide path 46 is arranged in an external surface 48 of the cylindrical wall 8 of the support member 7.

[0061] Optionally, the guide path 46 has multiple directions. Each guide path 46 comprises a central portion 46a which is oriented parallel to a circumferential direction around the setting axis A. A first portion 46b and a second portion 46c extend at each end of the central portion 46a. The directions of the first and second portions 46b, 46c of each guide path 46 are opposite and have an angle of inclination with the direction of the central portion 46a. Alternatively, the guide path is in the shape of an arc of a circle around the axis A and is concentric with the longitudinal axis X. All of the arcs of a circle form a circle centered on the longitudinal axis X. The guide path makes it possible, with this configuration, to simulate a circular control ring and to constrain the connection member 33 to move on a cylinder. This provides precision in the kinematics.

[0062] According to an exemplary embodiment, an angular zone 50 located at noon (with reference to a clock face) is devoid of variable-pitch blades so as to take into account the installation of a pylon of the turbomachine. The pylon (not shown) connects the nacelle of the turbomachine to the aircraft for example. The angular zone 50 is between +25° and -25° relative to a radial plane passing at noon and containing the longitudinal axis X.

[0063] We will now describe the kinematic operation of the pitch change system 3. When the or each control means 20 is controlled to change the pitch of the blades 2, the movable body 22 moves in translation which causes the pivoting of the or each control arm 23 and thus of the controlled blade root 4. The pivoting of the controlled blade root 4 2 about its pitch axis A simultaneously causes the movement of all the connecting rods 38. The connecting rods 38 transmit the movement and the angular pitch to the roots of the other variable-pitch blades (follower blade roots).

[0064] A single control means 20 makes it possible to directly control (via the control arm 23) a single blade root 2 and to control via one or more connecting rods 38 at least two roots 4 of variable-pitch blades 2 arranged adjacently around of the longitudinal axis. Advantageously, a control means 20 can control via one or more connecting rods 38 at least two variable-pitch blades 2. However, several control means 20 make it possible to better distribute the forces.

[0065] In this way, the connecting elements 32 make it possible to obtain precise and reliable timing of all the variable-pitch blades in the same direction.

Claims

Claims

1. A turbomachine module with a longitudinal axis (X), in particular for an aircraft, the module comprising a plurality of variable-pitch blades (2) around the longitudinal axis (X) and a pitch-changing system (3) for the variable-pitch blades (2), the pitch-changing system (3) comprising at least one control means (20) connected to a root (4) of at least one of the variable-pitch blades so as to control its rotation around its pitch axis (A) and connecting elements (32) which are arranged around the longitudinal axis (X), characterized in that each connecting element (32) is arranged between adjacent variable-pitch blades around the longitudinal axis (X) and each connecting element (32) is connected by articulated connections both to the roots (4) of the variable-pitch blades (2) and to an adjacent connecting element (32),each connecting element (32) being configured so as to transmit the rotational movement of the variable-pitch blade (2) controlled by the control means (20) to at least one other variable-pitch blade (2).,

2. Turbomachine module according to the preceding claim, characterized in that the pitch change system (3) comprises connection members (33) which are arranged around the longitudinal axis (X) and which are each connected to a foot (4), the connection elements (32) being mounted so as to be separated by at least one connection member (33) and each being articulated to a connection member (33).

3. Turbomachine module according to the preceding claim, characterized in that the articulated connection between each connecting element (32) and a connection member (33) is a ball joint connection.

4. Turbomachine module according to one of claims 2 and 3, characterized in that each foot (4) is connected to a connection member (33) by a sliding connection.

5. Turbomachine module according to one of the preceding claims, characterized in that the connecting elements (32) comprise connecting rods (38).

6. Turbomachine module according to one of claims 2 to 5, characterized in that the root (4) of each variable-pitch blade (2) is mounted to move about a pitch axis (A) in a support member (7) which is connected to a stator of the turbomachine, each connection member (33) being connected in an articulated manner to the support member (7).

7. Turbomachine module according to the preceding claim, characterized in that each connection member (33) comprises at least one roller (45) mounted to slide in a guide path (46) carried by the support member (7).

8. Turbomachine module according to one of the preceding claims, characterized in that the pitch change system (3) comprises a control arm (23) which is, on the one hand, integral with the root (4) of a variable-pitch blade (2) controlled by the control means (20) and which is, on the other hand, connected to the movable body (22) of the control means (21).

9. Turbomachine module according to the preceding claim, characterized in that the pitch change system (3) comprises several control means (20) distributed around the longitudinal axis (X) and in that each control means (20) is connected to the root (4) of a single variable-pitch blade (2) via the control arm (23) and each connecting element (32) is connected to a blade root and to an adjacent connecting element (32) around the longitudinal axis.

10. Turbomachine module according to one of the preceding claims, characterized in that a foot (2) controlled by a control means (20) comprises a control arm (23) and a lug (34) connected to at least one of the connecting elements (32) and a follower foot controlled by means of at least one of the connecting elements (32) comprises a single lug (34).

11. Turbomachine module according to any one of the preceding claims, characterized in that a control means (20) is intended to control at least two variable-pitch blades (2).

12. A turbomachine (1) comprising a turbomachine module according to any one of the preceding claims.

Images