BE1029457B1 - Aircraft turbomachine assembly, compressor, turbomachine and method for determining the angular pitch of blades - Google Patents

Abstract

The invention relates to an aircraft turbine engine assembly (10) comprising variable-pitch vanes (121, 131), movable in rotation around an axis of rotation (11) according to an angular pitch, a lever (12 ) for actuating each blade towards the angular setting, an index (18) whose angular position reflects the angular position of the lever (12), a potentiometer (20) whose output terminal is connected to the index (18) by a cable (21), the position of the index (18) is transmitted by the cable (21) to the potentiometer (20) and is a function of the ratio between the voltages at the output and at the input of the potentiometer (20). The invention also relates to an aircraft turbomachine compressor with such an assembly, a turbomachine with such a compressor and a method for determining the angular pitch of blades in such a turbomachine.

Description

- 1 - Aircraft turbomachine assembly, compressor, turbomachine and method for determining the angular pitch of blades Technical field The present invention relates to an aircraft turbomachine assembly, an aircraft turbomachine compressor with such an assembly, a turbomachine with such a compressor and a method for determining the angular pitch of blades in such a turbomachine.

PRIOR ART Aircraft turbomachine compressors may comprise adjustable blades within fixed blading.

For example, documents EP3382210 and EP3282096 describe variable-pitch turbine engine blades.

The blades include a pivot axis along which the pitch of the blade varies and magnetic means for guiding the blade in rotation along its pivot axis.

To measure the angular position of the blades, various solutions have been described in the state of the art.

The measurement of the angular setting of the blades requires the installation of sensors whose size may be too large in relation to the space available in the compressor casing, as well as in the space available between the casings, external to the primary stream. and internal of the secondary vein, in case it is necessary to carry out high precision measurements.

There is a need for a device which is simple and which makes it possible to obtain precise measurements of the angular setting of the blades without being cumbersome.

Presentation of the invention To this end, the invention proposes an aircraft turbomachine assembly comprising - variable-pitch blades, mobile in rotation around an axis of rotation according to an angular pitch, - an actuating lever for each blade towards the angular setting, - an index whose angular position reflects the angular position of the lever,

- 2 - - a potentiometer, one output terminal of which is connected to the index by a cable, the position of the index is transmitted by the cable to the potentiometer and is a function of the ratio between the output and input voltages of the potentiometer.

According to a variant, the cable is connected to the index by references.

According to a variant, Vindex is made in one piece with the lever.

According to a variant, the lever and Vindex are on either side with respect to the blade.

According to a variant, the index is diametrically opposed to the lever with respect to Taube.

The invention also relates to an aircraft turbine engine compressor comprising - a stator, - the aircraft turbine engine assembly as described previously, the bearings being supported by the stator, - a variable timing system controlling the timing angle of the blades by means of the lever the aircraft turbomachine assembly determining the effective angular setting of the blades according to the position of Vindex transmitted by the cable to the potentiometer and which is a function of the ratio between the voltages at the output and at the input of the potentiometer, the compressor being of the high pressure or low pressure type.

The invention also relates to an aircraft turbomachine comprising a low-pressure compressor and a high-pressure compressor located downstream of the low-pressure compressor along an engine axis, at least one of the compressors being as described above. .

According to a variant, the aircraft turbomachine further comprises - a fan upstream of the compressors along the engine axis, - a combustion chamber, a high pressure turbine and a low pressure turbine downstream of the compressors along the motor axis,

- 3 - - from the mechanical power transmission shafts of the high and low pressure turbines to the compressors and the fan via a reducer.

The invention also relates to a method for determining the angular pitch of blades in the aircraft turbine engine as described above, comprising the steps of - measuring the voltages at the input and output of the potentiometer for each blade whose angular pitch is to be determined, - determination of the effective angular setting of the blades according to the position of Vindex transmitted by the cable to the potentiometer and which is a function of the ratio between the voltages at the output and at the input of the potentiometer.

According to a variant, the method also comprises a step of comparing the actual angular pitch of the blades with the angular pitch controlled by a variable blade pitch system via the lever.

The use, in this document, of the indefinite article "un", "une", or of the definite article "le", "la" or "l'", to introduce an element does not exclude the presence of a plurality of these elements.

The terms "first", "second", etc. are, for their part, used within the framework of this document exclusively to differentiate between different elements, and this without implying any order between these elements.

The preferred embodiments as well as the advantages of the aircraft turbomachine assembly according to the invention transpose mutatis mutandis to the compressors, turbomachine and method for determining the angular pitch of the blades described.

Brief description of the figures Other characteristics and advantages of the present invention will become apparent on reading the following detailed description for the understanding of which reference will be made to the appended figures which show: - figure 1 illustrates a schematic view of a section two-dimensional view of an aircraft turbomachine on which it is planned to integrate the invention;

- 4 - - Figure 2, a schematic view of an example of an aircraft turbomachine assembly according to the invention; - Figure 3, a view of an embodiment of the invention.

Figure drawings are not to scale.

Like elements are generally denoted by like references in the figures.

In the context of this document, identical or similar elements may bear the same references.

Furthermore, the presence of reference numbers or letters in the drawings cannot be considered as limiting, including when these numbers or letters are indicated in the claims.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION The invention relates to an aircraft turbomachine assembly comprising variable-pitch blades, movable in rotation around an axis of rotation according to an angular pitch, an actuating lever of each blade towards the angular setting, an index whose angular position reflects the angular position of the lever, a potentiometer whose output terminal is connected to the index by a cable, the position of the index is transmitted by the cable to the potentiometer and depends on the ratio between the output and input voltages of the potentiometer.

This makes it possible to take precise measurements in a remote manner, which makes the elements for detecting the effective angular position of the blades compact.

The simplicity of the measuring elements ensures a long service life and insensitivity to temperature.

Figure 1 illustrates, by way of example, a section of an aircraft turbine engine 100 on which it is planned to integrate the aircraft turbine engine assembly according to the invention.

It may be more specifically an axial turbomachine comprising successively, along the engine axis X, a fan 110, a low pressure compressor 120, a high pressure compressor 130, a combustion chamber 160 , a high pressure turbine 140 and a low pressure turbine 150. These elements are known to those skilled in the art.

This is an example of architecture because the invention applies to other turbomachinery architectures.

In operation, the mechanical power of the low turbines

- 5 -

150 and high 140 pressure is transmitted via shafts 101 and 102 to the low 120 and high 130 pressure compressors respectively, as well as to the fan 110 via shaft 101. A reducer 111 can be interposed on shaft 101, so that the speeds of rotation of the fan 110 and of the low pressure compressor 120 are proportional.

The rotors of these compressors turn around the motor axis X allowing them to suck in and compress air to bring it to suitable speeds, pressures and temperatures, up to the inlet of the combustion chamber 160 The fan 110 makes it possible to generate primary 106 and secondary 107 air flows upstream of the low-pressure compressor 120. The primary air flow 106 is mainly intended to pass axially through the aircraft turbomachine 100, thereby supplying the combustion chamber 160, while the secondary air flow 107 is mainly intended to generate a thrust reaction necessary for the flight of the aircraft.

Although not systematically referenced in FIG. 1, each compressor and each turbine comprises one or more axial stages arranged in series.

Each stage comprises a stator or stator with fixed blades and a rotor with moving blades capable of being rotated around the motor axis.

For the low pressure 120 and high pressure 130 compressors, these fixed and mobile blades are respectively referenced by 121, 122 and 131, 132. Within a stage, the rotor draws in and accelerates the flow of primary air 106 by deflecting it with respect to the axis of the motor X and the stator or rectifier which follows straightens the flux in the motor axis X and slows it down by transforming part of its speed into pressure.

Stationary blading includes vanes that can be oriented fixed and/or oriented variable.

These adjustable vanes are also known as variable-pitch vanes, or according to the acronym "VSV" for "Variable Stator Vane". Their particularity is that the inclination of their strings can vary with respect to the axis of the X motor, and the axis of the compressors 120, 130 in particular.

The intrados and extrados faces of the blades can be more or less exposed to the primary airflow 106. The intrados surfaces extend more or less facing the primary airflow 106 in order to modulate the deflection, and therefore the recovery which is

- 6 - imposed on the primary air flow 106. The compressors may comprise one or more stages of adjustable blades.

The angular pitch (or orientation or position) of the vanes within the fixed vane stator is controlled by a variable pitch system.

In Figure 1, a variable valve timing system 123 may be mounted on the housing of the low pressure compressor 120; a variable timing system 133 can also be mounted on the crankcase of the high pressure compressor 130. It should be noted that this representation is in no way limiting of the number or position of the variable timing systems that the compressors 120 may include , 130. This type of architecture is given as an example, an intermediate compressor could be present.

The angular pitch of the blades with variable orientation within the fixed blades is controlled by the variable pitch systems 123, 133. An aircraft turbomachine assembly 10 illustrated schematically in FIGS. 2 and 3 makes it possible to determine the effective angular position of the blades variable orientation.

The assembly 10 makes it possible to know whether the blades have actually reached the controlled pitch.

FIG. 2 shows the assembly 10 with a vane 121, 131, with variable pitch, in cross section, among the stationary blades of the low pressure 120 and/or high pressure 130 compressor. An advantage of the assembly 10 is that it makes it possible to determine by simple and precise measurements the effective angular position of the blades thanks to a cable making it possible to deport the measuring devices in a free space of the casing 170. This is particularly advantageous for the low pressure compressor 120 which is located upstream of the motor, in the direction of flow of the primary and secondary air flows.

Indeed, the casing of the low pressure compressor 120 cannot be bulky because it is located in a location where the space is very small; the space is limited by the proximity of other engine elements, for example the presence of an air flow or the proximity of the outer casing in the radial direction of the engine.

The space can also be reduced due to the aerodynamic constraint of the aircraft, or even the constraint of integrating the engine into the aircraft.

- 7 - The variable-pitch vanes 121, 131 are mounted so as to rotate about an axis of rotation 11 according to an angular pitch. The blades 121, 131 are each rotatably mounted on a bearing of the assembly 10. The bearings are supported by a stator 14 integrated into the casing 170 of the compressors 120, 130.

The assembly 10 comprises a lever 12 for actuating the blade 121, 131 towards the controlled angular setting. The lever 12 is activated by the variable pitch system 123, 133 which activates a plurality of levers each actuating a blade towards an angular pitch. The system 123, 133 activates the lever 12 by a finger 13 located at one end of the lever 12. The lever 12 is connected to the blade 121, 131 by a conformation of the blade to actuate it in rotation towards the angular setting controlled by the system 123, 133. The lever 12 is activated in rotation by the system 123, 133 according to the arrow 16 around the axis of rotation 11 of the blade 121, 131 towards an angular position corresponding to the controlled angular setting of of dawn 121, 131.

According to Figure 2, the assembly 10 further comprises an index 18 whose position depends on that of the lever 12. The index 18 is rotatable around the axis of rotation 11 of the blade 121, 131 and its angular position reflects the angular position of the lever 12 and therefore the angular pitch of the blade. The circular movement of the index 18 is intended to cover the same angular stroke as the lever 12etlaube.

The assembly 10 further comprises a potentiometer 20 making it possible to determine the angular position of the index 18 and therefore the effective angular setting of the respective blades. An output terminal (visible in FIG. 3) of potentiometer 20 is connected to index 18 via a cable 21. The position of index 18 is transmitted to potentiometer 20 by cable 21, this position being a function of the ratio between the voltages at the output and at the input of the potentiometer 20. The arrow 40 in FIG. 2 shows the displacement of the cable 21 according to the movements of the index

18. Thus, the system 123, 133 activates the lever 12 towards an angular position to control an angular setting of the blade; the index 18 reflects the angular position of the lever 12 and the position of the index 18 is transmitted by the cable 21 to the potentiometer. The ratio between the output and input voltages of the potentiometer

- 8 - makes it possible to know the actual position of the index 18. If this actual position does not reflect the angular position of the lever 12 corresponding to the angular setting of the blade 121, 131 controlled by the system 123, 133 then there is a fault in the control by the system. A signal is issued for this purpose for corrective action. The potentiometer 20 is connected to the index 18 by the cable 21 via referrals. The transmissions allow the cable 21 to be routed from the potentiometer 20 to the index 18 inside the casing 170, taking into account the size in the latter. The geometry of the transmissions is chosen according to their rigidity and their sensitivity to vibrations in order to obtain precise measurements. In Figure 2, three references 31, 32, 33 are shown by way of example. The number of transmissions and their position are chosen so as to place the potentiometer 20 in a free space in the casing 170. The location of the first transmission 31 is at a distance D from the axis of rotation 11 of the blade 121, 131 (And at a height H relative to the plane of rotation of the index 18, when the reference point 31 is not in the plane of rotation of the index 18).

The index 18 can be in one piece with the lever 12. This makes it possible to manufacture the index and the lever in one piece, which also facilitates the positioning of the parts on the blade 121, 131. The lever 12 and the indexes 18 are on either side relative to the blade 121, 131. The advantage is that any deformation of the lever 12 during operation does not affect the index 18 in the same way. The angular position of the index 18 will not reflect the angular position of the lever 12 following the control of the system 123, 133 and therefore the angular setting of the actual blade will not correspond to the angular setting commanded by the angular setting system 123, 133 . Preferably, the index 18 is diametrically opposed to the lever 12 with respect to the tab 121, 131. This allows a simpler formation of the lever and the index.

Figure 3 shows a view of an embodiment of the invention. Figure 3 shows the potentiometer 20 comprising a terminal 22, a terminal 24 and an output terminal 26. The output terminal 26 is connected to a slider 28 of the potentiometer which moves on a resistive track 29 terminated by the two terminals 22 and 24.

The output terminal 26 is also connected to the index 18 via the cable 21. The rotational movements of the index 18 involve the movement of the cursor 28

- 9 - on resistive track 29 via cable 21, according to arrow 40 in FIG. 1. A voltage VT is applied between terminal 22 and terminal 24 of potentiometer 20. The output voltage VB between terminal 22 and the output terminal 26 depends on the position of the cursor 28 on the resistive track 29, the position of the cursor 28 on the resistive track 29 itself depending on the angular position of the index 18.

The position of the index 18 transmitted by the cable 21 to the potentiometer 20 can be determined as a function of the ratio between the voltages at the output and at the input of the potentiometer 20. More specifically, the angular position a of the index 18 can be determined by using the following formula (when the point of reference is in the plane of rotation of the index) U = arccos ( D” + R° 1” )

2.R.D 2.R.D with D the distance between the axis 11 of rotation of the blade 121, 131 and the first transmission 31, R the length between the axis 11 of rotation of the blade 121, 131 and the attachment point of the cable 21 to the index 18 and L the distance between the first transmission 31 and the point of attachment of the cable 21 to the index 18. Depending on the position of the index 18, L is determined using the potentiometer 20 and is a function of the ratio between VB and VT, that is, L = f(VB/VT).

The assembly 10 further comprises bushings (not visible in the figures) made of diamagnetic material ensuring the rotation of the blades in the bearings while avoiding metal/metal contact between the blades and the bearings. The advantage of the invention is that the measurement allows play (off-centering) linked to the presence of the bushings in the bearings.

The invention also relates to a method for determining the angular setting of the blades 121, 131 in the turbine engine 100 of the aircraft. The variable pitch system 123, 133 controls the angular pitch of the blades and the method makes it possible to know whether the blades have actually reached this angular pitch. The system 123, 133 controls an angular setting of the blades via the lever 12 for actuating each blade. The method comprises a step of measuring the voltages at the input VT and at the output VB of the potentiometer 20 for each blade 121, 131 whose angular setting is to be determined. Then the process includes

- 10 - a step of determining the effective angular setting of the blades 121, 131 according to the position of Vindex transmitted by the cable to the potentiometer; this position is a function of the ratio between the output and input voltages of the potentiometer.

This makes it possible to know the real position of the index 18 and therefore the effective angular setting of the blade.

Then the method comprises a step of comparing the actual angular pitch of the blades with the angular pitch controlled by the variable pitch system 123, 133 of the blades via the lever 12. An action can be taken according to the result of this comparison to modify the angular setting of the blades — or even carry out a maintenance step.

A control unit implements the process; it receives the voltages VT and VB and determines the effective angular pitch of the blades in order to compare it with the ordered angular pitch.

The invention is of particular interest in the low pressure compressor of the turbomachine comprising the reducer 111 on the mechanical power transmission shaft 101 of the turbines 150, 140. The reducer making it possible to increase the speed of rotation of the low pressure compressor 120 compared to that of the fan 110, the determination of the effective angular setting of the blades 121 of the low pressure compressor is all the more critical.

The housing of the low pressure compressor having little space available, the use of assembly 10 in the low pressure compressor is advantageous because the cable makes it possible to deport the potentiometer in a free space.

The position of the potentiometer can even be moved away from the respective vane.

The present invention has been described in relation to specific embodiments, which are purely illustrative and should not be construed as limiting.

In general, it will appear obvious to a person skilled in the art that the present invention is not limited to the examples illustrated and/or described above.

For example, the assembly described can be mounted on a turbine and the same advantages as described above apply.

Claims (10)

- 11 - Claims 1. Aircraft turbomachine assembly (10) comprising - vanes (121, 131) with variable pitch, movable in rotation about an axis of rotation (11) according to an angular pitch, - a lever (12) of actuation of each blade towards the angular setting, - an index (18) whose angular position reflects the angular position of the lever (12), - a potentiometer (20) whose output terminal is connected to the index (18) by a cable (21), the position of index (18) is transmitted by the cable (21) to the potentiometer (20) and is a function of the ratio between the voltages at the output and at the input of the potentiometer (20). 2 aircraft turbine engine assembly (10) according to claim 1, wherein the cable (21) is connected to the index (18) by references (31, 32, 33). 3. Aircraft turbine engine assembly (10) according to claim 1 or 2, in which the index (18) is integral with the lever (12). 4. Aircraft turbomachine assembly (10) according to one of claims 1 to 3, in which the lever (12) and the index (18) are on either side relative to the blade (121 , 131). 5. Aircraft turbine engine assembly (10) according to one of claims 1 to 4, wherein the index (18) is diametrically opposed to the lever (12) with respect to the blade (121, 131). 6. Aircraft turbomachine compressor (120, 130) comprising - a stator (14), - 12 - - the aircraft turbine engine assembly (10) according to one of claims 1 to 5, the bearings (12) being supported by the stator (14), - a variable pitch system (123, 133) controlling the angular setting of the blades (121, 131) via the lever (12), the aircraft turbine engine assembly (10) determining the effective angular setting of the blades (121, 131) according to the position of the index (18) transmitted by the cable (21) to the potentiometer (20) and which is a function of the ratio between the voltages at the output and at the input of the potentiometer, the compressor being of the high pressure or low pressure type. 7. Aircraft turbomachine (100) comprising a low pressure compressor (120) and a high pressure compressor (130) located downstream of the low pressure compressor (120) along an engine axis, at least one of the compressors (120, 130) being according to claim 6. 8. Aircraft turbomachine (100) according to claim 7, further comprising - a fan (110) upstream of the compressors (120, 130) along the engine axis, - a combustion chamber (160), a high pressure turbine (140) and a low pressure turbine (150) downstream of the compressors (120, 130) along the engine shaft, - shafts (101, 102) for transmitting the mechanical power of the high and low turbines pressure (140, 150) to the compressors (120, 130) and to the fan (110) via a reducer (111). 9. Method for determining the angular pitch of blades in the aircraft turbine engine (100) according to claim 7 or 8, comprising the steps of - measuring the voltages at the input and output of the potentiometer (20) for each blade (121 , 131) whose angular setting is to be determined, - 13 - - determination of the effective angular setting of the blades (121, 131) according to the position of the index (18) transmitted by the cable (21) to the potentiometer (20) and which is a function of the ratio between the output voltages and at the input of the potentiometer (20). 10. Method according to claim 9, further comprising a step of comparing the actual angular pitch of the blades with the angular pitch controlled by a variable pitch system (123, 133) of the blades via the lever (12).