FR3127533A1 - Wedging system for articulated turbomachine blade, turbomachine blade equipped with this wedging system and method of mounting such wedging system on an articulated blade - Google Patents

Abstract

Wedging system for articulated turbomachine blade, turbomachine blade equipped with this wedging system and method of mounting such wedging system on an articulated blade One aspect of the invention relates to a wedging system (30) for a foot (12) of an articulated turbomachine blade, said blade root being mounted so as to be able to rotate about a stacking axis (XX) of the blade, in a cavity (21) of a disk (20) of turbomachine, said wedging system comprising: a parallelepipedic drive base (31) forming a support for the blade root (12), a device (32) for converting a rotational movement of the blade root into a movement of axial translation, said motion conversion device being mounted at least partially around the drive base (31), anda spacer (33) mounted between the motion conversion device (32) and the disk (20) of so as to axially block the position of the blade root (12) with respect to the disc (20). Other aspects of the invention relate to an articulated blade wedged in the disk by means of this wedging system, a turbomachine equipped with such articulated blades and a method for mounting this wedging system on an articulated blade root. Figure to be published with abstract: Figure 2

Description

Wedging system for articulated turbomachine blade, turbomachine blade equipped with this wedging system and method of mounting such wedging system on an articulated blade

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a wedging system for an articulated turbomachine blade, such as a variable-pitch stator vane. It also relates to an articulated turbomachine blade equipped with such a wedging system as well as a turbomachine comprising such articulated blades. The invention also relates to a method for mounting this wedging system on an articulated blade.

The invention finds applications in the field of turbomachines and, in particular, in the field of variable-pitch stator vanes of a turbomachine.

The invention relates to the field of testing and makes it possible to test different blade angular settings.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

It is known, in aeronautics, that the power of an engine can be improved by using a system of articulated blades, orientable relative to the casing of the compressor of the engine. These articulated vanes, also called variable-pitch vanes, can be pivoted during engine operation in order to adapt their action according to engine speed and flight conditions, so as to regulate the flow of air supplying the compressor stages. located downstream.

An example of a hinged vane (also simply called a vane) is shown in the . An articulated vane 10 generally comprises a blade 11 extending between a blade root 12 and a blade heel 13. Each articulated vane 10 is provided with a control rod, pivotally mounted in an opening passing through the housing of the compressor and extended by a control lever itself connected to a control ring. Actuators make it possible to drive in rotation the control rings of the articulated vanes in order to tilt the levers, and thus orient said vanes.

In the lower part, the articulated blade is held in a cavity of the turbomachine disk by its blade root. The blade root is retained radially in the cavity of the disk by cooperation of shapes between said root, generally in the shape of a dovetail, and the cavity, generally in the form of a complementary cell. In operation, each row of blades is wedged angularly. We call "setting" the adjustment of a chosen angular position and the maintenance of this position set in operation. This chosen position corresponds to an optimal passive angle or orientation of the blade of the blade (relative to the axis of the turbomachine), that is to say its orientation when the compressor is stopped (or out of operation).

Several wedging techniques are generally used to wedge the root of a hinged blade in a disk cavity. One of these techniques consists of tightening the blade root directly in the cavity of the disc. However, this technique presents a compressive force applied to the blade root, which can be problematic when the blade root is made of composite material. In addition, maintaining the wedging by tightening requires a tightening force that is difficult to control and generates a risk of loss of tightening during operation.

Other techniques consist of adding an intermediate piece to the blade root. This intermediate piece can be, for example, a shim machined specifically for each desired angular setting value, this shim making it possible to maintain the orientation of the blade. However, this technique of adding a shim requires anticipating the orientation angles to be obtained and generates uncertainties in the blade-to-blade setting due to the manufacturing tolerances of the shims. This technique also results in play on the timing, substantially equivalent to the play in fitting the shim on the blade plus the play in fitting the blade in the disc.

The intermediate piece added to the blade root can also be a system of rods with a control ring (as on a conventional turbomachine with its VSV - Variable Stator Vanes system). However, the addition of such a system of rods generates uncertainties in the blade-to-blade setting due to the entire chain of ribs up to the control ring and the associated play, the chain of ribs intervening in the functional dimensioning of the mechanical assembly and making it possible in particular to check assembly clearances. The technique of adding a system of rods presents, in addition to the uncertainties of the wedging, a difficult assembly and installation adjustments. In addition, this technique leads to a certain heterogeneity of the mass and, consequently, an impact on the unbalance.

According to another technique, the intermediate part added can be a set of toothed wheels mounted on each blade root and meshed on a common toothed wheel around the motor shaft. However, this technique presents uncertainties in the blade-to-blade setting due to the entire chain of dimensions up to the control ring and the associated play. It also presents a risk of jamming after operation and difficulties in mounting and adjusting the installation.

There is therefore a real need for a wedging system making it possible to wed and maintain the wedging of the roots of the articulated blades in the cavities of the discs, at least passively (when the compressor is stopped).

To respond to the problems mentioned above of the various known wedging techniques, the applicant proposes a system for wedging an articulated blade root that is compact, evenly distributed and exhibits no play.

• une embase d’entraînement parallélépipédique formant support pour le pied d’aube,
• un dispositif de conversion d'un mouvement de rotation du pied d’aube en un mouvement de translation axiale, ledit dispositif de conversion de mouvement étant monté au moins partiellement autour de l’embase d’entraînement, et
• une entretoise montée entre le dispositif de conversion et le disque de sorte à bloquer axialement la position du pied d’aube par rapport au disque.

According to a first aspect, the invention relates to a wedging system for an articulated turbine engine blade root, said blade root being mounted so as to be able to rotate about a blade stacking axis, in a cavity of a turbomachine disk, said wedging system comprising:

• a parallelepipedal drive base forming a support for the blade root,
• a device for converting a rotational movement of the blade root into an axial translational movement, said movement conversion device being mounted at least partially around the drive base, and
• a spacer mounted between the conversion device and the disc so as to axially block the position of the blade root relative to the disc.

Such a system for wedging an articulated blade in passive mode has the advantage, on the one hand, of not having any play and, on the other hand, of being compact due to the reduced number of parts which are all housed within of a disc cavity.

• le dispositif de conversion de mouvement comporte une vis à billes et un écrou à billes monté autour de ladite vis à billes.
• la vis à billes comporte un orifice recevant au moins partiellement l’embase d’entraînement.
• l’orifice de la vis à billes est un orifice traversant ou un orifice borgne logé à une extrémité de la vis à billes.
• l’entretoise est logée entre l’écrou à billes du dispositif de conversion de mouvement et le disque de la turbomachine.
• l’entretoise est montée autour de la vis à billes.

In addition to the characteristics which have just been mentioned in the previous paragraph, the wedging system according to one aspect of the invention may have one or more additional characteristics among the following, considered individually or according to all technically possible combinations:

• the motion conversion device comprises a ball screw and a ball nut mounted around said ball screw.
• the ball screw has an orifice at least partially receiving the drive base.
• the ball screw hole is a through hole or a blind hole in one end of the ball screw.
• the spacer is housed between the ball nut of the motion conversion device and the disc of the turbomachine.
• the spacer is mounted around the ball screw.

A second aspect of the invention relates to a variable-pitch turbine engine blade comprising a blade extending between a blade heel and a blade root, said blade root being rotatably mounted inside a cavity of a turbomachine disc. This blade is characterized by the fact that it includes a wedging system as defined previously.

Advantageously, the blade wedging system is mounted around the stacking axis inside the cavity of the turbomachine disk.

A third aspect of the invention relates to a turbomachine comprising blades as defined above.

• montage de l’embase d’entraînement sur le pied d’aube,
• montage de l’aube dans le disque de turbomachine,
• montage du dispositif de conversion de mouvement autour de l’embase d’entraînement,
• réglage du calage de l’aube, et
• lorsque l’aube est calée dans le disque selon une configuration choisie, installation de l’entretoise pour maintenir axialement le dispositif de conversion de mouvement.

According to a fourth aspect, the invention relates to a method for mounting a wedging system comprising the following operations:

• assembly of the drive base on the blade root,
• assembly of the blade in the turbomachine disc,
• mounting the motion conversion device around the drive base,
• adjustment of the vane timing, and
• when the blade is keyed in the disc according to a chosen configuration, installation of the spacer to axially hold the motion conversion device.

Advantageously, the motion conversion device is mounted by shrinking on the drive base.

• une étape de montage de la vis à billes sur l’embase d’entraînement, et
• une étape de vissage de l’écrou à billes autour de la vis à billes jusqu’à une butée prédéfinie sur le disque.

According to certain embodiments, the motion conversion device comprises a ball screw and a ball nut mounted around said ball screw, the operation of mounting the motion conversion device then comprising:

• a step for mounting the ball screw on the drive base, and
• a step of screwing the ball nut around the ball screw to a predefined stop on the disc.

BRIEF DESCRIPTION OF FIGURES

Other advantages and characteristics of the invention will appear on reading the following description, illustrated by the figures in which:

There , already described, schematically represents an example of a variable-pitch stator vane seen in profile;

There shows a schematic sectional view of an embodiment of the wedging system according to the invention for wedging an articulated blade root mounted in a disc cavity;

There shows an example of a ball screw used in one embodiment of the wedging system according to the invention;

There shows a schematic view of another example of a hinged blade root wedging system; And

There represent several schematic views of the wedging system according to the invention during its assembly on an articulated blade root.

Claims (12)

Wedging system (30) for an articulated turbine engine blade root (12), said blade root being mounted so as to be able to rotate about a stacking axis (XX) of the blade, in a cavity (21 ) of a turbine engine disc (20), said wedging system comprising:

• a parallelepipedal drive base (31) forming a support for the blade root (12),
• a device (32) for converting a rotational movement of the blade root into an axial translational movement, said movement conversion device being mounted at least partially around the drive base (31), and
• a spacer (33) mounted between the motion conversion device (32) and the disc (20) so as to axially lock the position of the blade root (12) relative to the disc (20).

Wedging system according to claim 1, characterized in that the motion conversion device (32) comprises a ball screw (321) and a ball nut (322) mounted around said ball screw. Wedging system according to Claim 2, characterized in that the ball screw (321) comprises an orifice (321c) at least partially receiving the drive base (31). Wedging system according to Claim 3, characterized in that the orifice (321c) of the ball screw (321) is a through orifice or a blind orifice housed at one end of the ball screw. Wedging system according to any one of Claims 2 to 4, characterized in that the spacer (33) is housed between the ball nut (322) of the motion conversion device and the disk (20) of the turbomachine. . Wedging system according to any one of Claims 2 to 5, characterized in that the spacer (33) is mounted around the ball screw (321). Variable-pitch turbomachine blade (10) comprising a blade (11) extending between a blade root (13) and a blade root (12), said blade root being rotatably mounted at the interior of a cavity (21) of a turbomachine disc (20),
characterized in that it includes a wedging system (30) according to any one of claims 1 to 6. Turbomachine blade according to Claim 7, characterized in that the wedging system (30) is mounted around the stacking axis (XX) inside the cavity (21) of the turbomachine disc. Turbomachine comprising blades according to any one of claims 7 and 8. Method for mounting a wedging system (30) according to any one of claims 1 to 6 on a foot (12) of an articulated turbine engine blade, said method comprising the following operations:

• mounting the drive base (31) on the blade root (12),
• mounting of the articulated blade (10) in the disc (20) of the turbomachine,
• mounting (A, B) of the motion conversion device (32) around the drive base (31),
• adjustment (C) of the setting of the hinged blade, and
• when the articulated blade (10) is keyed in the disc (20) according to a chosen configuration, installation of the spacer (33) to axially hold the motion conversion device.

Mounting method according to Claim 10, characterized in that the motion conversion device (32) is mounted by shrink-fitting on the drive base (31). Mounting method according to Claim 10 or 11, characterized in that the movement conversion device (32) comprises a ball screw (321) and a ball nut (322) mounted around the said ball screw, the operation mounting of the motion conversion device (32) then comprising:

• a step (A) of mounting the ball screw on the drive base, and
• a step (B, C) of screwing the ball nut (322) around the ball screw (321) up to a predefined stop (25) on the disc.