BE1029455B1 - 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 bearings (12), vanes (121, 131) with variable pitch, guided in rotation by the bearings (12) around an axis of rotation (11) according to an angular setting, potentiometers (20) of which an output terminal is connected to a respective blade guided in rotation by the bearing, the angular setting of the blades being a function of the ratio between the voltages at the output and at the input of the potentiometers respective. 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 position of the blade actuation systems can be measured to deduce therefrom the angular position of the blades or else an offset measurement of an element of the blade such as the position of a lever linked to the blade or of a shaft and gear system for driving the blades.

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.

Also, it must be added elements for measuring the setting of the blades which are complex to adjust and which may have operating clearances.

Each of these constraints, mainly complexity and operating clearances, are antagonistic to the desired measurement precision.

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.

- 2 - Presentation of the invention To this end, the invention proposes an aircraft turbomachine assembly comprising - bearings, - variable-pitch vanes, guided in rotation by the bearings around an axis of rotation along a angular setting, - potentiometers, one output terminal of which is connected to a respective vane guided in rotation by the bearing, the angular setting of the vanes being a function of the ratio between the output and input voltages of the respective potentiometers.

According to a variant, the potentiometer is centered on the axis of rotation of the blade.

According to a variant, the vanes extend through the potentiometer.

According to a variant, the aircraft turbomachine assembly further comprises a support holding the potentiometer at one end of the bearing from which Taube emerges.

According to a variant, the support surrounds the circumference of the bearing.

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, the aircraft turbomachine assembly determining the effective angular setting of the blades as a function of the ratio between the voltages at the output and at the input of the respective potentiometers, the compressor being of the high pressure or low pressure type.

More generally, the compressor is of any type, including intermediate.

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

- 3 - compressors being as previously described. More generally, the turbomachine comprises several compressors with different pressure levels. 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 shaft, - shafts transmitting the mechanical power of the high and low pressure turbines to the compressors and the fan via a reduction gear.

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 of each blade, - determining the effective angular setting of the blades as a function of the ratio between the output and input voltages of the potentiometer.

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

The use, in this document, of the verb "understand", its variants, as well as its conjugations, can in no way exclude the presence of elements other than those mentioned. 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 terms "high pressure" and "low pressure" are used in this document exclusively to differentiate between different compressors, without implying a particular engine architecture.

- 4 - The preferred embodiments as well as the advantages of the aircraft turbomachine assembly according to the invention transpose mutatis mutandis to the compressors, turbomachine, turbines 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; - 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 bearings, variable-pitch vanes, guided in rotation by the bearings around an axis of rotation according to an angular pitch and potentiometers, one output terminal of which is connected to a respective vane guided in rotation by the bearing. The angular setting of the blades is a function of the ratio between the output and input voltages of the respective potentiometers. This makes it possible to take measurements directly at the level of the blade to be monitored, which makes the measurements precise and makes the elements for detecting the effective angular position of the blades simple and less cumbersome. The simplicity of the measuring elements ensures a long service life and insensitivity to temperature.

- 5 -

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 150 and high 140 pressure turbines 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 the 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 tubomachine 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.

The

- 6 - fixed vanes include vanes which can be fixed orientation and/or variable orientation.

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 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 and equipped in the same way.

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, by way of example, of the fixed 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 while being compact in the casing of the compressors.

This is particularly advantageous for the low pressure compressor 120 which is located upstream of the

- 7 - 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. 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 12 of the assembly 10. The bearings 12 are supported by a stator 14 integrated into the casing 170 of the compressors 120,

130. The assembly 10 further comprises potentiometers 20 making it possible to determine the effective angular setting of the respective blades. An output terminal (visible in FIG. 3) of potentiometer 20 is connected to blade 121, 131. This makes it possible to link the potentiometer to the rotational movements of blade 121, 131 and the angular setting of the blade then a function of the ratio between the voltages at the output and at the input of the potentiometer 20. between a negative terminal of the potentiometer and the output terminal of the potentiometer connected to the blade and on the other hand the voltage between the negative terminal of the potentiometer and a positive terminal of the potentiometer. Figure 3 shows a view of an embodiment of the invention. Figure 3 shows the potentiometer 20, which is for example a variohm type sensor. The potentiometer 20 includes a terminal 22 (negative), a terminal 24 (positive) 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 variation of the slider 28 along the resistive track 29 varies the resistance between the terminals 22 and 24. The output terminal 26 is also connected to the blade 121, 131 whose angular setting is to be determined. The

- 8 - rotation movements of the blade 121, 131 involve the displacement of the cursor 28 on the resistive track 29. 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 setting of the blade 121, 131. The output voltage VB therefore depends on the variable resistance between terminals 22 and 24 depending on the position of slider 28. The angular setting of the blade 121, 131 is then a function of the ratio (or ratio) between the voltages VB at the output and VT at the input of the potentiometer 20. In other words, the angular setting a is such that a= f (VB/VT).

FIG. 2 shows an example of the position of the potentiometer 20 for determining the angular setting of a blade 121, 131. The potentiometer 20 is preferably centered on the axis of rotation 11 of the blade 121, 131 whose angular setting is determined. This makes it possible to accurately measure the movement of the blade 121, 131. According to the example of FIG. 2, the blade 121, 131 extends through the potentiometer 20. This position allows simple connection of the output terminal 26 at dawn 121, 131 without recourse to intermediate parts. In addition, this position is of limited size. By way of example, and along axis 11, the height of potentiometer 20 is less than 15 mm.

The potentiometer 20 is for example held in position by a support 30. The support 30 can surround the circumference of the bearing 12 and rest on the stator

14. The advantage of such a support 30 is that it involves little or no modification of the existing bearing 12. Support 30 can thus hold potentiometer 20 centered on axis of rotation 11 of blade 121, 131. Potentiometer 20 is for example held in position at one end of bearing 12 from which blade 121 emerges. , 131 by the support 30. This allows easy access to the blade 121, 131 to connect the output terminal 26 of the potentiometer 20 thereto. Thus, such a support 30 makes it possible to directly equip the bearing with the potentiometer 20 and to record the movements of the blade in a simple and precise way. Fixing elements 32, such as screws, hold the potentiometer 20 in position on the support 30.

- 9 - Thus, the detection of the effective angular position of each blade is carried out by means which do not require additional elements.

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 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 method comprises a step of measuring the voltages at the input VT and at the output VB of the potentiometer 20 of each blade 121, 131 whose angular setting is to be determined; then the method comprises a step of determining the effective angular setting of the blades 121, 131 as a function of the ratio between the voltages at the output and at the input of the respective potentiometers 20. This makes it possible to know the real position of the blades 121, 131. 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. Depending on the result of this comparison, action can be taken to modify the angular setting of the blades — or even carry out a maintenance step. A control unit implements the method; 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. Since the 10 assembly is precise and space-saving and the housing of the low pressure compressor has little space available, the use of the 10 assembly in the low pressure compressor is advantageous.

- 10 -

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 - bearings (12), - vanes (121, 131) with variable pitch, guided in rotation by the bearings (12) around an axis of rotation (11) according to an angular setting, - potentiometers (20) of which an output terminal is connected to a respective blade guided in rotation by the bearing, the angular setting of the blades being a function of the ratio between the voltages at the output and at the input of the respective potentiometers. 2. Aircraft turbomachine assembly (10) according to claim 1, in which the potentiometer (20) is centered on the axis of rotation (11) of the blade (121, 131). 3. Aircraft turbomachine assembly (10) according to claim 1 or 2, in which the blades (121, 131) extend through the potentiometer (20). 4. Aircraft turbomachine assembly (10) according to one of claims 1 to 3, further comprising a support (30) holding the potentiometer (20) at one end of the bearing (12) from which the blade emerges (121, 131). 5. Aircraft turbomachine assembly (10) according to claim 4, in which the support (30) surrounds the circumference of the bearing (12). 6. Aircraft turbine engine compressor (120, 130) comprising - a stator (14), - the aircraft turbine engine assembly (10) according to one of claims 1 to 5, the bearings (12) being supported by the stator (14), - 12 - - a variable pitch system (123, 133) controlling the angular pitch of the blades (121, 131), the aircraft turbine engine assembly (10) determining the effective angular pitch of the blades (121, 131) by depending on the ratio between the output and input voltages of the respective potentiometers, 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) of each blade, - determination of the effective angular setting of the vanes (121, 131) as a function of the ratio between the voltages at the output and at the input of the potentiometer (20). - 13 - 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.